METHOD AND APPARATUS FOR MAPPING OPERATING PARAMETER IN
COVERAGE AREA OF WIRELESS NETWORK
BACKGROUND
This disclosure relates to providing wireless service to a mobile station in a
wireless network and more particularly, but not exclusively, to mapping an
operating parameter in a coverage area of a wireless network.
Geographic location information for mobile stations has tremendous value
to mobile applications, network optimization (e.g., self optimized network (SON)),
capacity management, and drive test substitutions, etc. Although many modern
mobile stations can obtain their own locations from integrated GPS modules, it is
still a challenge for the network to track the locations of a large number of
subscribers for an extended period of time. A frequent location update from
mobile stations would increase network overhead and may overwhelm the
network and create bottlenecks. A passive location estimation technique that
leverages measurements from normal network operation is desirable because it
avoids such increases in network overhead.
For example, in third generation (3G) code division multiple access
(CDMA) networks, such as 3G1X, EVDO, UMTS, etc., one can triangulate the
geographic location of a mobile station from the reported round trip delays
between the mobile station and three or more base stations (see FIG. 1). The
corresponding round trip delays are sent back by the mobile stations for call
processing, thus no additional signaling overhead is incurred by the network to
collect measurements for triangulation.
However, this triangulation approach does not work in all networks, such
as the fourth generation (4G) long term evolution (LTE) networks. Unlike 3G
CDMA networks, each measurement report in LTE networks only contains the
round trip delay from one cell (i.e., the serving cell of the mobile). Thus, the
triangulation technique cannot be used at all in conjunction with 4G LTE
networks.
Additionally, geographic location information for mobile stations has
tremendous value in compilation and formulation of RF coverage maps for
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wireless networks. RF coverage maps are useful for management of the network
infrastructure and the wireless services provided to users and subscribers. For
example, RF coverage maps may be useful to network operators and service
providers for troubleshooting and planning for maintenance and upgrades.
However, most of the RF coverage maps are obtained through drive tests.
Accurate RF coverage map take hours of drive tests and are very costly.
Moreover, as network evolve and environment changes, such as adding new
cells or new building construction, the drive tests have to be redone to keep the
coverage information up to date. Thus, maintenance of RF coverage maps using
drive testing adds even more to the cost.
For these and other reasons, there is a need to provide a technique for
estimating a geographic location of a mobile station for at least 4G LTE networks.
Additionally, it is desirable that the technique be compatible with other types of
wireless networks, especially 3G CDMA networks it is also desirable that the
technique be more reliable than the triangulation technique. Additionally, it is
desirable that the technique for estimating a geographic location of a mobile
station support construction or maintenance of RF coverage maps in a more cost
effective manner than the drive testing technique ft is also desirable to map
other types of parameters collected in conjunction with normal operation of the
wireless network in coverage area maps.
SUMMARY
In one aspect, a method for mapping an operating parameter in a
coverage area of a wireless network is provided. In one embodiment, the
method includes: obtaining parameter measurements for a select operating
parameter associated with one or more mobile stations operating in at least a
select portion of a network coverage area for a wireless network, the parameter
measurements having been measured during a select calendar timeframe, the
network coverage area formed by a plurality of base stations, each base station
defining a cellular coverage area within the network coverage area, the select
portion of the network coverage area formed by at least one base station, each at
least one base station including multiple sector antennas, each sector antenna
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defining a sector coverage area within the cellular coverage area for the
corresponding base station; and for each obtained parameter measurement,
estimating an instant geographic location of the corresponding mobile station in
relation to the at least one base station serving the corresponding mobile station,
each instant geographic location based at least in part on a round trip
measurement and at least one signal strength measurement associated with the
corresponding mobile station, each round trip measurement associated with the
at least one base station serving the corresponding mobile station, each round
trip measurement and corresponding at least one signal strength measurement
related in calendar time to the corresponding parameter measurement.
In another aspect an apparatus for mapping an operating parameter in a
coverage area of a wireless network is provided in one embodiment, the
method includes: an input module and a location module. The input module for
obtaining parameter measurements for a select operating parameter associated
with one or more mobile stations operating in at least a select portion of a
network coverage area for a wireless network. The parameter measurements
having been measured during a select calendar timeframe. The network
coverage area formed by a plurality of base stations. Each base station defining
a cellular coverage area within the network coverage area. The select portion of
the network coverage area formed by at least one base station. Each at least
one base station including multiple sector antennas. Each sector antenna
defining a sector coverage area within the cellular coverage area for the
corresponding base station. The location module in operative communication
with the input module for estimating an instant geographic location of the
corresponding mobile station for each obtained parameter measurement in
relation to the at least one base station serving the corresponding mobile station.
Each instant geographic location based at least in part on a round trip
measurement and at least one signal strength measurement associated with the
corresponding mobile station. Each round trip measurement associated with the
at least one base station serving the corresponding mobile station. Each round
trip measurement and corresponding at least one signal strength measurement
related in calendar time to the corresponding parameter measurement.
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ln yet another aspect, a non-transitory computer-readable medium storing
program instructions that, when executed by a computer, cause a corresponding
computer-controlled device to perform a method for mapping an operating
parameter in a coverage area of a wireless network n one embodiment of the
non-transitory computer-readable medium, the method includes: obtaining
parameter measurements for a select operating parameter associated with one
or more mobile stations operating in at least a select portion of a network
coverage area for a wireless network, the parameter measurements having been
measured during a select calendar timeframe, the network coverage area formed
by a plurality of base stations, each base station defining a cellular coverage
area within the network coverage area, the select portion of the network
coverage area formed by at least one base station, each at least one base
station including multiple sector antennas, each sector antenna defining a sector
coverage area within the cellular coverage area for the corresponding base
station; and for each obtained parameter measurement, estimating an instant
geographic location of the corresponding mobile station in relation to the at least
one base station serving the corresponding mobile station, each instant
geographic location based at least in part on a round trip measurement and at
least one signal strength measurement associated with the corresponding mobile
station, each round trip measurement associated with the at least one base
station serving the corresponding mobile station, each round trip measurement
and corresponding at least one signal strength measurement related in calendar
time to the corresponding parameter measurement.
Further scope of the applicability of this the present invention will become
apparent from the detailed description provided below it should be understood,
however, that the detailed description and specific examples, while indicating
preferred embodiments of the invention, are given by way of illustration only,
since various changes and modifications within the spirit and scope of the
invention will become apparent to those skilled in the art.
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DESCR1PT10N OF THE DRAWINGS
The present invention exists in the construction, arrangement, and
combination of the various parts of the device, and steps of the method, whereby
the objects contemplated are attained as hereinafter more fully set forth,
specifically pointed out in the claims, and illustrated in the accompanying
drawings in which:
F G. 1 is a functional diagram showing three cells of a wireless network in
relation to an exemplary embodiment of a triangulation technique for estimating
the geographic location of a mobile station;
FfG. 2 is a functional diagram showing a serving cell of a wireless network
in relation to an exemplary embodiment of another technique for estimating the
geographic location of a mobile station;
FIG. 3 is a graph showing a transmit antenna gain characteristic for a
sector antenna of a base station in which normalized gain in dB is plotted in
relation to look angles from the sector antenna to a mobile station in relation to
azimuth (i.e., horizontal gain) and elevation (i.e., vertical gain) positions from the
orientation of the sector antenna;
FfG. 4 is a flow chart of an exemplary embodiment of a process for
estimating a geographic location of a mobile station within a coverage area of a
wireless network;
FiG. 5, in combination with FIG. 4, is a flow chart of another exemplary
embodiment of a process for estimating a geographic location of a mobile station
within a coverage area of a wireless network;
FIG. 6 is a block diagram of an exemplary embodiment of an apparatus
within a serving base station of a wireless network for estimating a geographic
location of a mobile station within a coverage area of the wireless network;
FiG. 7 is a block diagram of an exemplary embodiment of an apparatus
within a geo-location service node of a wireless network for estimating a
geographic location of a mobile station within a coverage area of the wireless
network;
FiG. 8 is a block diagram of an exemplary embodiment of an apparatus
within a network management node associated with a wireless network for
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estimating a geographic location of a mobile station within a coverage area of the
wireless network;
FiG. 9 is a block diagram of an exemplary embodiment of an angular
position module associated with the apparatus shown in FIGs. 6-8;
FiG. 10 is a flow chart of an exemplary embodiment of a process for
estimating a geographic location of a mobile station within a coverage area of a
wireless network performed by a computer-controlled device executing program
instructions stored on a non-transitory computer-readable medium;
FIG. 11 is a bird's eye view of a coverage area of an exemplary base
station in a wireless network showing an estimated geographic location and a
GPS location for a mobile station;
FiG. 12 is a set of graphs showing azimuth gain parameter characteristics
for two sector antennas of a base station, elevation gain parameter
characteristics for the two sector antennas, a composite graph showing the
difference between gains for the two sector antennas, and a graph of a function
of the angular position of the mobile station in relation to the delta antenna gain
component, a delta transmit parameter component, and a delta signal strength
measurement component;
FiG. 13 is a functional diagram showing three base stations, each with
three sector antennas, in relation to exemplary embodiments of various
techniques for estimating the geographic location of a mobile station;
FiG. 14 is an example of an RF coverage map for a sector antenna of a
base station that is used in relation to an exemplary embodiment of a technique
for estimating the geographic location of a mobile station;
FiG. 15 is another example of an RF coverage map for a sector antenna of
a base station that is updated in conjunction with an exemplary embodiment of a
technique for estimating the geographic location of a mobile station;
FiG. 16 is yet another example of an RF coverage map for a sector
antenna of a base station that is used in relation to another exemplary
embodiment of a technique for estimating the geographic location of a mobile
station;
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FiG. 17 is a flow chart of an exemplary embodiment of a process for
estimating a geographic location of a mobile station within a coverage area of a
wireless network;
F G. 18, in combination with FIG. 17, is a flow chart of another exemplary
embodiment of a process for estimating a geographic location of a mobile station
within a coverage area of a wireless network;
FIG. 19, in combination with FIG. 17, is a flow chart of yet another
exemplary embodiment of a process for estimating a geographic location of a
mobile station within a coverage area of a wireless network;
FfG. 20 is a flow chart of still another exemplary embodiment of a process
for estimating a geographic location of a mobile station within a coverage area of
a wireless network;
FIG. 2 1, in combination with FIG. 20, is a flow chart of still yet another
exemplary embodiment of a process for estimating a geographic location of a
mobile station within a coverage area of a wireless network;
FfG. 22, in combination with FIG. 20, is a flow chart of another exemplary
embodiment of a process for estimating a geographic location of a mobile station
within a coverage area of a wireless network;
FiG. 23 is a flow chart of yet another exemplary embodiment of a process
for estimating a geographic location of a mobile station within a coverage area of
a wireless network;
FIG. 24 is an exemplary set of signaling usage maps for a cluster of
cellular coverage areas for a wireless network showing six 1-hour samples of
signaling usage over a 24-hour period;
FiG. 25 is an exemplary set of data usage maps showing a map for all
devices in the cluster of cellular coverage areas and maps for certain types of
devices during a 1-hour sample of data usage;
FIG. 26 is an exemplary set of signaling usage maps showing a map for all
devices in the cluster of cellular coverage areas and maps for certain types of
devices during a 1-hour sample of signaling usage;
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FiG. 27 is an exemplary set of population maps showing a map for all
active devices in the cluster of cellular coverage areas and maps for certain
types of devices during a 1-hour sample of active devices;
FIG. 28 is a flow chart of an exemplary embodiment of a process for
mapping an operating parameter in a coverage area of a wireless network;
FiG. 29, in combination with FIG. 28, is a flow chart of another exemplary
embodiment of a process for mapping an operating parameter in a coverage
area of a wireless network;
FIG. 30, in combination with FIG. 28, is a flow chart of yet another
exemplary embodiment of a process for mapping an operating parameter in a
coverage area of a wireless network;
FiG. 3 1, in combination with FIGs. 28 and 30, is a flow chart of a further
exemplary embodiment of a process for mapping an operating parameter in a
coverage area of a wireless network;
FIG. 32, in combination with FIGs. 28 and 30, is a flow chart of another
further exemplary embodiment of a process for mapping an operating parameter
in a coverage area of a wireless network;
FiG. 33 is a block diagram of an exemplary embodiment of an apparatus
within a network management node associated with a wireless network for
mapping an operating parameter in a coverage area of the wireless network; and
FiG. 34 is a flow chart of an exemplary embodiment of a process for
mapping an operating parameter in a coverage area of a wireless network
performed by a computer-controlled device executing program instructions stored
on a non-transitory computer-readable medium.
DETAILED DESCRIPTION
Various embodiments of methods and apparatus provide techniques for
mapping an operating parameter in a coverage area of a wireless network. In
one embodiment, parameter measurements associated with operation of a
mobile station in a coverage area of a base station having multiple sector
antennas are obtained for a select operating parameter, obtaining a round trip
measurement and at least one signal strength measurement associated with the
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mobile station, estimating the instant geographic location of the mobile station
based at least in part on the round trip measurement and the at least one signal
strength measurement to relate instant geographic locations with each parameter
measurement. Various techniques for processing and mapping the parameter
measurements in coverage area maps based at least in part on the estimated
geographic locations are also presented. For example, any suitable operating
parameter that is measured in conjunction normal operations of mobile stations
in the wireless network can be mapped, such as signal strength measurements
in RF coverage maps, data or signaling usage for communication sessions in
usage maps, device or application usage in population maps, and throughput,
packet loss, or packet delay in quality of service maps. The various
embodiments described herein provide improved accuracy of information in
location estimates for mobile stations by combining measurements for both the
distance and signaling strength/quality reports in the algorithm for estimating the
location.
The estimating of the geographic location of mobile stations in conjunction
with mapping parameter measurements can be accomplished using any of the
various embodiments of methods and apparatus for estimating a geographic
location of a mobile station described below in the descriptions of FIGs. 1-27.
Depending on the operating parameter, maps can be generated to indicate
network performance, coverage, usage, and end user experience or activities.
The maps are generated based on real user information. Actual users can be
indoors or outdoors, can be in fast moving vehicle or stationary. Conversely, for
measurements obtained from drive test data, the drive test device is normally in a
moving vehicle in an outdoor environment to which the vehicle has access.
Metrics of interest, such as coverage, usage, user experience and activities, etc
can be tracked for all active users during any select calendar time. In fact,
tracking could be continuous using a rolling time window. Limitations on
calendar time for tracking or the size of the rolling time window may arise if
limitations on storage capacity are encountered. On the other hand, drive test
data can only be collected in conjunction with scheduled drive tests that are
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usually set up for a certain time of the day and is one time event. Drive test data
cannot reflect network operation conditions 24 hours a day, seven days a week.
The various embodiments of methods and apparatus for estimating a
geographic location of a mobile station described below in the descriptions of
FIGs. 1-27 can be used to estimate the geographic location of mobile stations in
conjunction with the measurement of operating parameters to be mapped. The
operating parameters can be selected so that the maps indicate network
performance, coverage, usage and end user experience. These maps can be
used for optimizing the wireless network (SON), troubleshooting, network
planning, etc.
The various types of coverage area maps include RF coverage maps,
usage maps, population maps, user experience maps, and user profile maps.
RF coverage maps can provide RF coverage map for a given cell, a given sector
of a cell, or a cluster of cells. If multiple sector antennas of a base station cover
a given sub-sector area of the map, the sector antenna providing the strongest
coverage may be mapped. RF coverage maps that show call drop locations and
handoff zones can be generated.
Usage maps can be generated for all active devices or by device type,
device model, and software application in various combinations. Usage maps
can show data usage or signaling usage for communication sessions.
Population maps can also be generated for all active devices or by device type,
device model, or software applications in various combinations. For example,
population maps plot the number of active devices for a given device model,
such as the number of iPhones active in a 50 meter by 50 meter sub-sector
geographic area (i.e., geo-bin area). User experience maps can be generated
for all active devices or by device type, device model, or software application in
various combinations. User experience maps plot metrics (i.e., parameter
measurements) reflecting quality of service, such as throughput, packet loss, or
packet delay. For example, a throughput map for a YouTube software
application or a packet loss map for a Blackberry device. User profile maps may
be generated per geographic location or geographic area. For example, user
profile maps can show software applications used, web sites visited, etc.
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With reference to FIG. 24, an exemplary set of signaling usage maps for a
cluster of cellular coverage areas for a wireless network shows six 1-hour
samples of signaling usage over a 24-hour period. An exemplary embodiment of
a process for generating data usage maps during different hours of the day
includes dividing an area of interest into sub-sector geographic areas (i.e., geobins).
For example, a geo-bin size can represent a 50 meter by 50 meter subsector
geographic area within the coverage area of a wireless network or a
portion thereof. For a given call record during the given hour, the process
includes estimating the mobile station location by using any suitable embodiment
of the network-based geo-location method discussed below in the descriptions of
FIGs. 1-27. The mapping process also includes extracting data usage
information from the call record and storing the usage amount in the
corresponding geo-bin for the given hour. The data usage information in the
geo-bin can be processed to determine a representative usage value to be
mapped in the sub-sector geographic area of the coverage area map.
With reference to FIG. 25, an exemplary set of data usage maps shows a
map for all devices in the cluster of cellular coverage areas and maps for certain
types of devices during a 1-hour sample of data usage. Similarly, FiG. 26 shows
an exemplary set of signaling usage maps, including a map for all devices in the
cluster of cellular coverage areas and maps for certain types of devices during a
1-hour sample of signaling usage. FIG. 27 shows an exemplary set of population
maps, including a map for all active devices in the cluster of cellular coverage
areas and maps for certain types of devices during a 1-hour sample of active
devices.
With reference to FIG. 28, an exemplary embodiment of a process 2800
for mapping an operating parameter in a coverage area of a wireless network
begins at 2802 where parameter measurements for a select operating parameter
associated with one or more mobile stations operating in at least a select portion
of a network coverage area for a wireless network are obtained. The parameter
measurements having been measured during a select calendar timeframe. The
network coverage area formed by a plurality of base stations. Each base station
defining a cellular coverage area within the network coverage area. The select
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portion of the network coverage area formed by at least one base station. Each
at least one base station including multiple sector antennas. Each sector
antenna defining a sector coverage area within the cellular coverage area for the
corresponding base station. At 2804, for each obtained parameter
measurement, an instant geographic location of the corresponding mobile station
is estimated in relation to the at least one base station serving the corresponding
mobile station. Each instant geographic location based at least in part on a
round trip measurement and at least one signal strength measurement
associated with the corresponding mobile station. Each round trip measurement
associated with the at least one base station serving the corresponding mobile
station. Each round trip measurement and corresponding at least one signal
strength measurement related in calendar time to the corresponding parameter
measurement.
With reference to FIGs. 28 and 29, another exemplary embodiment of a
process 2900 for mapping an operating parameter in a coverage area of a
wireless network includes the process 2800 of FIG. 28 and continues with 2902
where obtained parameter measurements for each instant geographic location
are processed to obtain a representative parameter value for the corresponding
instant geographic location. At 2904, a coverage area map for the wireless
network is populated with the representative parameter values based at least in
part on the instant geographic location associated with the corresponding
representative parameter value. The coverage area map including at least the
select portion of the network coverage area.
in another embodiment of the process 2900, the representative parameter
values are obtained by filtering the corresponding parameter measurements to
remove unreliable measurements, averaging the corresponding parameter
measurements, determining a median value for the corresponding parameter
measurements, selecting a preferred parameter measurement from the
corresponding parameter measurements based at least in part on a preferred
calendar time for the corresponding representative parameter value, any other
suitable processing technique, or any suitable combination thereof.
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ln yet another embodiment of the process 2900, the coverage area map is
an RF coverage area map, a handoff zone coverage area map, a data usage
coverage area map, a signaling usage coverage area map, a population
coverage area map for directory number identification, device identification,
device type, or application program, a quality of service coverage area map for
throughput, packet loss, or packet delay, a user profile coverage area map, any
other suitable coverage area map, or any suitable combination thereof.
With reference to FfGs. 28 and 30, yet another exemplary embodiment of
a process 3000 for mapping an operating parameter in a coverage area of a
wireless network includes the process 2800 of FIG. 28. In this embodiment, at
least the select portion of the network coverage area is represented in a
coverage area map for the wireless network by a plurality of sub-sector
geographic areas. Each sub-sector geographic area uniquely identified and
associated with at least a portion of the sector coverage area for at least one
sector antenna. At 3002, each estimated instant geographic location is
correlated with a sub-sector geographic area of the plurality of sub-sector
geographic areas. Each sub-sector geographic area adapted to represent more
than one instant geographic location. The correlating based at least in part on a
reference location in the coverage area map for the at least one base station
serving the mobile station associated with the corresponding instant geographic
location.
With reference to FIGs. 28, 30, and 3 1, a further exemplary embodiment of
a process 3100 for mapping an operating parameter in a coverage area of a
wireless network includes the processes 2800, 3000 of FIGs. 28 and 30 and
continues with 3102 where obtained parameter measurements for each subsector
geographic area are processed to obtain a representative parameter value
for the corresponding sub-sector geographic area. At 3104, the coverage area
map is populated with the representative parameter values based at least in part
on the sub-sector geographic area associated with the corresponding
representative parameter value.
With reference to FIGs. 28, 30, and 32, another further exemplary
embodiment of a process 3200 for mapping an operating parameter in a
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coverage area of a wireless network includes the processes 2800, 3000 of FIGs.
28 and 30. In this embodiment, each sub-sector geographic area is associated
with a corresponding geographic location bin for storage of parameter
measurements associated with the instant geographic locations represented by
the corresponding sub-sector geographic. At 3202, each obtained parameter
measurement is stored in a geographic location bin associated with the subsector
geographic area representing the instant geographic location associated
with the corresponding parameter measurement. Next, the parameter
measurements stored in each geographic location bin is processed to obtain a
representative parameter value for the corresponding geographic location bin
(3204). At 3206, the coverage area map is populated with the representative
parameter values based at least in part on the geographic location bin associated
with the corresponding representative parameter value and the sub-sector
geographic area associated with the corresponding geographic location bin.
With reference again to FIG. 28, in another embodiment of the process
2800, the parameter measurements are obtained from call records, subscriber
records, service provider records, other suitable types of wireless data records,
or any suitable combination thereof. The records may include data that is
captured and/or maintained during normal operation of the wireless network that
provide wireless services to mobile stations. The records may also include data
that supports accounting and billing functions for the service provider.
in yet another embodiment of the process 2800, the select operating
parameter includes one or more of a signal strength parameter associated with
RF signals received by mobile stations from sector antennas, a handoff
parameter associated with handoffs of mobile stations from serving sector
antennas to neighboring sector antennas of serving base stations or neighboring
base stations, a data usage parameter associated with data usage during call
sessions to and from mobile stations, a signaling usage parameter associated
with setup and teardown of call sessions to and from mobile stations, a directory
number identification parameter associated with telephone numbers for mobile
stations, a device identification parameter associated with serial numbers of
mobile stations, a device type parameter associated with categorizing mobile
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stations into different types by manufacturer, model, or technical feature, an
application identification parameter associated with application programs used by
mobile stations, a throughput parameter associated with call sessions for mobile
stations, a packet loss parameter associated with call sessions for mobile
stations, a packet delay parameter associated with call sessions for mobile
stations, a user profile parameter associated with observed behavior or
preferences of users of mobile stations, or any other suitable operating
parameter.
In still another embodiment of the process 2800, the select portion of the
network coverage area is formed by at least two base stations. In the
embodiment being described, each at least two base stations including multiple
sector antennas in still yet another embodiment of the process 2800, at least
some instant geographic locations are based at least in part on the round trip
measurement and first and second signal strength measurements of the at least
one signal strength measurement. In this embodiment, the first and second
signal strength measurements being from different sector antennas.
In another embodiment of the process 2800, at least some instant
geographic locations are based at least in part on the round trip measurement, a
first signal strength measurement of the at least one signal strength
measurement, and a first RF coverage map for a first sector antenna serving the
mobile station associated with the round trip measurement and with which the
first signal strength measurement is associated in a further embodiment of the
process 2800, one or more instant geographic locations are also based at least
in part on a second signal strength measurement of the at least one signal
strength measurement and a second RF coverage map for a second sector
antenna with which the second signal strength measurement is associated, the
second sector antenna associated with a neighboring base station in relation to
the base station serving the mobile station.
In yet another embodiment of the process 2800, parameter measurements
are obtained and the instant geographic locations are estimated in response to
detection of a dropped call for the one or more mobile stations.
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With reference to FIG. 33, an exemplary embodiment of an apparatus for
mapping an operating parameter in a coverage area of the wireless network
includes an input module 3300 and a location module 3302. The input module
3300 for obtaining parameter measurements for a select operating parameter
associated with one or more mobile stations operating in at least a select portion
of a network coverage area for a wireless network. The input module 3300 may
obtain the parameter measurements from the components of the wireless
network, an operation and maintenance (OAM) system, a charging system, a
billing system, or any suitable combination thereof. The parameter
measurements having been measured during a select calendar timeframe. The
network coverage area formed by a plurality of base stations. Each base station
defining a cellular coverage area within the network coverage area. The select
portion of the network coverage area formed by at least one base station. Each
at least one base station including multiple sector antennas. Each sector
antenna defining a sector coverage area within the cellular coverage area for the
corresponding base station.
The location module 3302 in operative communication with the input
module 3300 for estimating an instant geographic location of the corresponding
mobile station for each obtained parameter measurement in relation to the at
least one base station serving the corresponding mobile station. Each instant
geographic location based at least in part on a round trip measurement and at
least one signal strength measurement associated with the corresponding mobile
station. The round trip and the at least one signal strength measurement
obtained via the input module 3300. The input module 3300 may obtain the
round trip measurements and signal strength measurements from the
components of the wireless network, OAM system, charging system, billing
system, or any suitable combination thereof. Each round trip measurement
associated with the at least one base station serving the corresponding mobile
station, each round trip measurement and corresponding at least one signal
strength measurement related in calendar time to the corresponding parameter
measurement.
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ln the embodiment being described, the apparatus may include a network
management node 3304 associated with the wireless network and in operative
communication with wireless network storage node(s) 3306, OAM storage
node(s) 3308, charging system storage node(s) 3310, and billing system storage
nodes(s) 3312 to obtain parameter measurements for operating parameters
associated with mobile stations, including round trip measurements and signal
strength measurements from call records 3314, subscriber records 3316, service
provider records 3318, or any suitable combination thereof. The network
management node 3304 is in operative communication with a network operator
terminal 3320 to facilitate management of the infrastructure for the core wireless
network by the network operator. The network management node 3304 is also in
operative communication with a wireless service provider terminal 3322 to
facilitate management of a service provided to subscribers via the core wireless
network by the provider of the wireless service.
In another embodiment, the network management node 3304 may also
include a processing module 3324 and a mapping module 3326. The processing
module 3324 in operative communication with the input module 3300 and
location module 3302 for processing the obtained parameter measurements for
each instant geographic location to obtain a representative parameter value for
the corresponding instant geographic location. The mapping module 3326 in
operative communication with the processing module 3324 for populating a
coverage area map for the wireless network with the representative parameter
values based at least in part on the instant geographic location associated with
the corresponding representative parameter value, the coverage area map
including at least the select portion of the network coverage area. The network
management node 3304 may make coverage area maps accessible to
authorized network operators via the network operator terminal 3320 and/or
accessible to authorized wireless service providers via the wireless service
provider terminal 3322. For example, the coverage area maps may be
communicated to the network operator terminal 3320 and/or wireless service
provider terminal 3322 via the mapping module 3326 in as an image of the
coverage area map or as data reflecting the representative parameter values,
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instant geographic locations, and other map information in a form suitable for the
corresponding terminal to construct the image of the coverage area map.
In a further embodiment of the network management node 3304, the
processing module 3324 obtains the representative parameter values by one or
more of filtering the corresponding parameter measurements to remove
unreliable measurements, averaging the corresponding parameter
measurements, determining a median value for the corresponding parameter
measurements, selecting a preferred parameter measurement from the
corresponding parameter measurements based at least in part on a preferred
calendar time for the corresponding representative parameter value, any other
suitable processing technique, or any suitable combination thereof.
In an alternate further embodiment of the network management node
3304, the coverage area map is an RF coverage area map, a handoff zone
coverage area map, a data usage coverage area map, a signaling usage
coverage area map, a population coverage area map for directory number
identification, device identification, device type, or application program, a quality
of service coverage area map for throughput, packet loss, or packet delay, a user
profile coverage area map, any other suitable coverage area map, or any
suitable combination thereof.
In yet another embodiment of the network management node 3304, at
least the select portion of the network coverage area is represented in a
coverage area map for the wireless network by a plurality of sub-sector
geographic areas. Each sub-sector geographic area uniquely identified and
associated with at least a portion of the sector coverage area for at least one
sector antenna. In this embodiment, the network management node 3304 also
includes a correlation module 3328 in operative communication with the location
module 3302 for correlating each estimated instant geographic location with a
sub-sector geographic area of the plurality of sub-sector geographic areas. Each
sub-sector geographic area adapted to represent more than one instant
geographic location. The correlating based at least in part on a reference
location in the coverage area map for the at least one base station serving the
mobile station associated with the corresponding instant geographic location.
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ln a further embodiment, the network management node 3304 also
includes the processing module 3324 and mapping module 3326. In this
embodiment, the processing module 3324 is in operative communication with the
input module 3300 and correlating module 3328 for processing the obtained
parameter measurements for each sub-sector geographic area to obtain a
representative parameter value for the corresponding sub-sector geographic
area. In the embodiment being described, the mapping module 3326 is in
operative communication with the processing module 3324 for populating the
coverage area map with the representative parameter values based at least in
part on the sub-sector geographic area associated with the corresponding
representative parameter value.
In an alternate further embodiment of the network management node
3304, each sub-sector geographic area is associated with a corresponding
geographic location bin for storage of parameter measurements associated with
the instant geographic locations represented by the corresponding sub-sector
geographic in this embodiment, the network management node 3304 also
includes a storage device 3330, processing module 3324, and mapping module
3326. The storage device 3330 in operative communication with the input
module 3300 and the location module 3302 for storing each obtained parameter
measurement in a geographic location bin associated with the sub-sector
geographic area representing the instant geographic location associated with the
corresponding parameter measurement. The storage device 3330 also stores
the round trip and signal strength measurements used by the location module
3302. in this embodiment, the processing module 3324 is in operative
communication with the storage device 3330 and correlating module 3328 for
processing the parameter measurements stored in each geographic location bin
to obtain a representative parameter value for the corresponding geographic
location bin. In the embodiment being described, the mapping module 3326 is in
operative communication with the processing module 3324 for populating the
coverage area map with the representative parameter values based at least in
part on the geographic location bin associated with the corresponding
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representative parameter value and the sub-sector geographic area associated
with the corresponding geographic location bin.
In still another embodiment of the network management node 3304, the
input module 3300 obtains the parameter measurements from call records 3314,
subscriber records 3316, and service provider records 3318 captured or
maintained during normal operation of the wireless network that provide wireless
services to mobile stations or that support accounting and billing functions for the
service provider. The call records 3314, subscriber records 3316, and service
provider records 3318 may be obtained from storage in the wireless network
storage node(s) 3306, OAM storage node(s) 3308, charging system storage
node(s) 3310, billing system storage node(s) 3312, or any suitable combination
thereof.
In still yet another embodiment of the network management node 3304,
the select operating parameter includes one or more of a signal strength
parameter associated with RF signals received by mobile stations from sector
antennas, a handoff parameter associated with handoffs of mobile stations from
serving sector antennas to neighboring sector antennas of serving base stations
or neighboring base stations, a data usage parameter associated with data
usage during call sessions to and from mobile stations, a signaling usage
parameter associated with setup and teardown of call sessions to and from
mobile stations, a directory number identification parameter associated with
telephone numbers for mobile stations, a device identification parameter
associated with serial numbers of mobile stations, a device type parameter
associated with categorizing mobile stations into different types by manufacturer,
model, or technical feature, an application identification parameter associated
with application programs used by mobile stations, a throughput parameter
associated with call sessions for mobile stations, a packet loss parameter
associated with call sessions for mobile stations, a packet delay parameter
associated with call sessions for mobile stations, a user profile parameter
associated with observed behavior or preferences of users of mobile stations, or
any other suitable operating parameter.
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ln another embodiment of the network management node 3304, the select
portion of the network coverage area is formed by at least two base stations. In
the embodiment being described, each at least two base stations including
multiple sector antennas. In yet another embodiment of the network
management node 3304, at least some instant geographic locations estimated by
the location module 3302 are based at least in part on the round trip
measurement and first and second signal strength measurements of the at least
one signal strength measurement. In this embodiment, the first and second
signal strength measurements being from different sector antennas.
In still another embodiment of the network management node 3304, at
least some instant geographic locations estimated by the location module 3302
are based at least in part on the round trip measurement, a first signal strength
measurement of the at least one signal strength measurement, and a first RF
coverage map for a first sector antenna serving the mobile station associated
with the round trip measurement and with which the first signal strength
measurement is associated. In a further embodiment of the network
management node 3304, one or more instant geographic locations estimated by
the location module 3302 are also based at least in part on a second signal
strength measurement of the at least one signal strength measurement and a
second RF coverage map for a second sector antenna with which the second
signal strength measurement is associated, the second sector antenna
associated with a neighboring base station in relation to the base station serving
the mobile station.
In still yet another embodiment of the network management node 3304,
parameter measurements are obtained by the input module 3300 and the instant
geographic locations are estimated by the location module 3302 in response to
detection of a dropped call for the one or more mobile stations.
With reference to FIG. 34, an exemplary embodiment of a non-transitory
computer-readable medium storing program instructions that, when executed by
a computer, cause a corresponding computer-controlled device to perform a
process 3400 for mapping an operating parameter in a coverage area of a
wireless network n one embodiment, the process 3400 begins at 3402 wherein
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parameter measurements for a select operating parameter associated with one
or more mobile stations operating in at least a select portion of a network
coverage area for a wireless network are obtained. The parameter
measurements having been measured during a select calendar timeframe. The
network coverage area formed by a plurality of base stations. Each base station
defining a cellular coverage area within the network coverage area. The select
portion of the network coverage area formed by at least one base station. Each
at least one base station including multiple sector antennas. Each sector
antenna defining a sector coverage area within the cellular coverage area for the
corresponding base station. At 3404, for each obtained parameter
measurement, an instant geographic location of the corresponding mobile station
is estimated in relation to the at least one base station serving the corresponding
mobile station. Each instant geographic location based at least in part on a
round trip measurement and at least one signal strength measurement
associated with the corresponding mobile station. Each round trip measurement
associated with the at least one base station serving the corresponding mobile
station. Each round trip measurement and corresponding at least one signal
strength measurement related in calendar time to the corresponding parameter
measurement.
In another embodiment, the process 3400 may also include processing the
obtained parameter measurements for each instant geographic location to obtain
a representative parameter value for the corresponding instant geographic
location. In this embodiment, a coverage area map for the wireless network is
populated with the representative parameter values based at least in part on the
instant geographic location associated with the corresponding representative
parameter value. In the embodiment being described, the coverage area map
includes at least the select portion of the network coverage area.
In various embodiments, the program instructions stored in the nontransitory
computer-readable memory, when executed by the computer, may
cause the computer-controlled device to perform various combinations of
functions associated with the various embodiments of the processes 2800, 2900,
3000, 3100, and 3200 for mapping an operating parameter in a coverage area of
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a wireless network described above with reference to FIGs. 28-32. In other
words, the various embodiments of the processes 2800, 2900, 3000, 3100, and
3200 described above may also be implemented by corresponding embodiments
of the process 3400 associated with the program instructions stored in the nontransitory
computer-readable memory.
Similarly, the program instructions stored in the non-transitory computerreadable
memory, when executed by the computer, may cause the computercontrolled
device to perform various combinations of functions associated with
the various embodiments of the processes for estimating a geographic location of
a mobile station 400, 500, 1700, 1800, 1900, 2000, 2100, 2200, and 2300 (see
FIGs. 4, 5, and 17-23) in conjunction with estimating the instant geographic
location of a mobile station in 3404. In other words, the various embodiments of
the processes 400, 500, 1700, 1800, 1900, 2000, 2100, 2200, and 2300
described above may also be implemented by corresponding embodiments of
the process 3400 associated with the program instructions stored in the nontransitory
computer-readable memory, particularly the estimating of the instant
geographic location in 3404.
Likewise, in various embodiments, the program instructions stored in the
non-transitory computer-readable memory, when executed by the computer, may
cause the computer-controlled device to perform various combinations of
functions associated with the various embodiments of the apparatus for mapping
an operating parameter in a coverage area of a wireless network described
above with reference to FIG. 33, the apparatus for estimating a geographic
location of a mobile station described above with reference to FIG. 8, and the
angular position module 906 described above with reference to FIG. 9.
For example, the computer-controlled device may include a network
management node (see FIG. 33, item 3304; FIG. 8, item 828), or any suitable
communication node associated with the wireless network. Any suitable module
or sub-module described above with reference to FIGs. 8, 9, and 33 may include
the computer and non-transitory computer-readable memory associated with the
program instructions. Alternatively, the computer and non-transitory computerreadable
memory associated with the program instructions may be individual or
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combined components that are in operative communication with any suitable
combination of the modules and sub-modules described above with reference to
FIGs. 8,9,and 33.
With reference to FIG. 3, a functional diagram shows three base stations,
each with three sector antennas, in relation to exemplary embodiments of various
techniques for estimating the geographic location of a mobile station by dividing
the wireless service area into different categories of circumstances for estimating
the location. Different types of data are available for the different categories.
Thus, the techniques for estimating geographic location are adjusted for each
category based on the type of data available under the corresponding
circumstance.
In a category 1 area, mobile station locations can be determined by an
algorithm that calculates an angular position of the mobile station in relation to a
serving or neighboring base station using signal strength measurements from
multiple sector antennas of the base station in a measurement report from the
mobile station and determines a radial distance of the mobile station from the
serving base station based on a round trip measurement. Various embodiments
of algorithms for the category 1 area are provided below in the descriptions of
FIGs. 1-12 and 17-19.
With continued reference to FIG. 13, category 2 areas are locations in
which the mobile station is only receiving signal strength measurements from one
sector antenna from each of one, two, or more base stations. Category 2 areas
can be viewed as the rest of the coverage area for a given cell (or given sector)
of the wireless network that do not fit under the category 1 circumstances in a
category 2 area, the mobile station location is determined based on the
combination of determining a radial distance of the mobile station from a serving
based station based on a round trip measurement and a strength measurements
from one sector antenna of each of one, two, or more base stations in a
measurement report from the mobile station to identify potential sub-sector
geographic coverage areas in an RF coverage map for a serving sector antenna
of the serving base station populated with an RF coverage level representative of
lacking previous signal strength measurements, and using RF coverage levels in
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the RF coverage map for neighboring sub-sector geographic coverage areas to
estimate the geographic location of the mobile station. Various embodiments of
algorithms for the category 1 area are provided below in the descriptions of FIGs.
6-10 and 20-22.
With continued reference to FIG. 3, for each sub-sector geographic area
in the RF coverage map, a geo-bin is used to store signal strengths for the
corresponding sub-sector geographic area. The RF coverage level for the subsector
geographic area is updated over time by averaging (or by taking a median
value) over multiple records of signal strength measurements. Study has shown
that the longer the observation period, the more accurate the results are for the
corresponding RF coverage level. For example, eight hours of signal strength
measurements results in an RF coverage level that is more accurate than signal
strength measurements spanning one hour for the same area.
An exemplary embodiment of techniques for estimating the geographic
location of a mobile station for category 1 and category 2 circumstances are
described below. RF coverage maps may be built up by taking enough
measurement data over a suitable period of time to generate suitable initial RF
coverage maps. For example, taking eight hours of per call measurement data
(PCMD) in down town busy areas may be used to generate an RF coverage
map. The RF coverage maps my be built up from geographic locations for the
mobile stations obtained using the techniques described herein or by other
suitable location determining techniques.
The measurement data may be divided into category 1 and category 2
circumstances. Category 1 measurements contain signal strength
measurements by the mobile station from the same base station, but different
sectors. The rest of the measurement data belongs to category 2 circumstances.
Each category may be further divided into sub categories. An example of
how to generate an initial RF coverage map for base station 1, sector a for
subcategory 1A circumstances is based on the mobile station seeing two pilots
from different sectors (sector a and sector b) of base station 1. Both pilots may
be used to estimate the mobile station location by using a suitable embodiment
of the algorithm disclosed herein. In addition, the pilot from base stationl , sector
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a may also be used to plot an RF coverage map for the corresponding sector a
antenna based on category A geographic location estimates for the mobile
station.
Similarly, an example of how to generate an initial RF coverage map for
base station , sector a for subcategory B circumstances is based on the mobile
station seeing two pilots from different sectors (sector b and sector g ) of base
station 3 and one pilot from base station 1, sector a . The two pilots from base
station 3, sector b and sector g are used to estimate the mobile location by using
the algorithm disclosed herein. The pilot from base stationl , sector a may be
used to plot an RF coverage map for the corresponding sector a antenna based
on category 1B geographic location estimates for the mobile station.
As for subcategory 2A, the mobile station only sees a single pilot from
base station 1, sector a. Hence, in subcategory 2A circumstances, the mobile
station is around a bore sight area for base station , sector a where it is most
likely that only one pilot is seen by the mobile station. Here, the mobile station
location is estimated by using the pilot information, distance information, and RF
coverage levels and corresponding geo-bin information for sub-sector geographic
areas that are neighboring potential sub-sector geographic areas with RF
coverage levels showing that previous signal strength measurements are lacking.
With the geographic location for the mobile station identified, the pilot from base
station 1, sector a may also be used to supplement (or plot) an RF coverage map
of the sector under category 2 circumstances.
As for subcategory 2B, the mobile station sees one pilot from base station
1, sector a and another pilot from base station 2, sector b. Hence, in
subcategory 2B circumstances, the mobile station is around an area between
base station 1 and base station 2. Here, the mobile station location is estimated
using both pilots information and distance information combined with RF
coverage levels and corresponding geo-bin information for sub-sector geographic
areas that are neighboring potential sub-sector geographic areas with RF
coverage levels showing that previous signal strength measurements are lacking
to get a more accurate estimation of the mobile station location. With the
geographic location for the mobile station identified, the pilot from base station 1,
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sector a may also used to supplement (or plot) an RF coverage map of the sector
under category 2 circumstances.
With reference to FIG. 14, an example of an RF coverage map for a sector
antenna of a base station is shown that can be used in conjunction with an
exemplary embodiment of a technique for estimating the geographic location of a
mobile station. In various exemplary embodiments of techniques for estimating
the geographic location of a mobile station, the category 1 measurements can be
used to build category 1 RF coverage maps (including measurements associated
with subcategory A and subcategory 1B circumstances). Various embodiments
of the algorithm to obtain mobile station geographic location in category 1
circumstances is described in more detail below in the descriptions of FIGs. 1-12
and 17-19.
With continued reference to FIGs. 14 and 15, signal strength
measurements from category 2 circumstances can be combined with category 1
RF coverage maps and/or existing signal strength measurement information
stored in geo-bins associated with neighboring sub-sector geographic areas to
generate category 2 RF coverage maps. For example, in FIG. 14, in a category
1 area, including areas for subcategory 1A and subcategory 1B circumstances,
an RF coverage map for base station A, sector 3 is already built from previous
category 1 signal strength measurements. The category 1 RF coverage map
shows that areas for subcategory 2A and subcategory 2B for base station A,
sector 3 do not currently have valid Ec/lo information.
As for subcategory 2A, the mobile station sees a pilot from base station A,
sector 3 with Ec/lo at -5 dB. In the mean time, base station A, sector 3 measured
the round trip delay associated with the mobile station to be equivalent to
distance d. In this example, there are two sub-sector geographic areas and
corresponding geo-bins that are associated with the distance d criteria in the
area associated with subcategory 2A circumstances. The technique goes on to
determine which sub-sector geographic area or corresponding geo-bin signal
measurements in the area for subcategory 2A circumstances is associated with
the mobile station location.
ln the embodiment being described, the sub-sector geographic area and
corresponding geo-bin in the base station A, sector 3 area just north of the area
associated with subcategory 2A circumstances has Ec/lo at -2 dB. The subsector
geographic area and corresponding geo-bin in the base station A, sector 3
area just south of the area associated with subcategory 2A circumstances has
Ec/lo at -6 dB. In this embodiment, the southern sub-sector geographic area and
corresponding geo-bin in area associated with subcategory 2A circumstances is
chosen to indicate the mobile station location because the measurement report
of pilot Ec/lo at -5 dB is closer to -6dB than -2 dB. The updated overall RF
coverage map for base station A, sector 3 is shown in FIG. 15.
With continued reference to FIG. 14, as for subcategory 2B, the mobile
station sees a pilot from base station A, sector 3 with Ec/lo at -7 dB and another
pilot from base station B, sector 2. In the mean time, base station A, sector 3
measured the round trip delay associated with the mobile station to be equivalent
to distance d. In this example, there are two sub-sector geographic areas and
corresponding geo-bins that are associated with the distance d in the area
associated with subcategory 2B measurements. In the embodiment being
described, the sub-sector geographic areas and corresponding geo-bins
neighboring the areas associated with the category 2B circumstances in the base
station A, sector 3 coverage area have pilot Ec/lo signals around -7dB. The next
step is to determine which sub-sector geographic area and corresponding geobin
in the potential category 2B areas the mobile station is located.
In the embodiment being described, the northern sub-sector geographic
area and corresponding geo-bin is chosen to indicate the mobile station location
because the northern bin is located between base station A and base station B
where it is most likely that pilots from both base stations can be seen by the
mobile station. The updated overall RF coverage map for base station A, sector
3 is shown in FIG. 15.
With reference to FIGs. 14 and 15, the RF coverage level for the subsector
geographic area can continue to be updated in the RF coverage maps for
each individual base station (i.e., sector antenna) by averaging (or by taking the
median value) over multiple records for a corresponding geo-bin.
With reference to FiG. 6, yet another example of an RF coverage map for
a sector antenna of a base station is shown that can be used in conjunction with
another exemplary embodiment of a technique for estimating the geographic
location of a mobile station. In this embodiment, the geographic location of a
mobile station can be estimated based on RF coverage maps for various
circumstances, such as dropped call locations. Study has shown that the longer
the observation period, the more accurate the results are for the corresponding
RF coverage level. On the other hand, for some events, like dropped calls, it is
very important to know where the calls are dropped. However, under normal
circumstances, dropped calls are not experienced very often in the wireless
network. In another exemplary embodiment, a technique for estimating the
location of a mobile station includes an algorithm to estimate dropped call
locations for mobile stations on existing RF coverage maps.
In this embodiment, the mobile station reports Ec/lo of base station A,
sector 3 at -3 dB and Ec/lo of base station B, sector 3 at -4 dB. The distance
between the mobile station and the serving sector antenna (i.e., base station A,
sector 3) is determined to be distance d. The process uses existing RF coverage
maps for these sectors to identify RF coverage levels and corresponding geobins
that closely match these signal strength measurements. Moreover, the
process uses the distance measurement to define a circle centered at base
station A with a radius defined by distance d on which the closely matching RF
coverage levels and corresponding geo-bins are identified.
For example, the closely matching RF coverage levels for sub-sector
geographic areas and corresponding geo-bins in a first RF coverage map for
base station A may have Ec/lo values within a range of -3dB +/- Threshold_s,
where Threshold_s is a threshold for the serving sector antenna (i.e., base
station A, sector 3). For example, Threshold_s can be set at 0.25 dB. Similarly,
the closely matching RF coverage levels for sub-sector geographic areas and
corresponding geo-bins in a second RF coverage map for base station B may
have Ec/lo values within a range of -4dB +/- Threshold_n, where Threshold_n is
a threshold for the neighboring sector antenna (i.e., base station B, sector 3).
For example, Threshold_n can be set at 0.5 dB. The red dot in FIG. 16 shows the
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estimated mobile station location after overlaying the sub-sector geographic area
identified in the second RF coverage map on the first RF coverage map to locate
matching RF coverage levels from both RF coverage maps that intersect.
With reference to FIG. 17, an exemplary embodiment of a process 1700
for estimating a geographic location of a mobile station within a coverage area of
a wireless network begins at 1702 where an instant angular position of an
individual mobile station in relation to a first base station is calculated. The first
base station including multiple sector antennas. The instant angular position
based at least in part on a first signal strength measurement, a second signal
strength measurement, and an angular position reference that extends outward
from the first base station. The first and second signal strength measurements
related in calendar time and representative of power characteristics of respective
RF signals received by the individual mobile station from corresponding first and
second sector antennas of the first base station.
With reference to FIGs. 17 and 18, another exemplary embodiment of a
process 1800 for estimating a geographic location of a mobile station within a
coverage area of a wireless network includes the process 1700 of FfG. 17 and
continues at 1802 where a radial distance of the individual mobile station from
the first base station is determined. The radial distance based at least in part on
a round trip measurement associated with elapsed time between sending an
outgoing signal from the first base station to the individual mobile station and
receiving a corresponding acknowledgement signal from the individual mobile
station at the first base station. The round trip measurement related in calendar
time to the first and second signal strength measurements.
In another embodiment, the process 1800 also includes identifying an
instant geographic location of the individual mobile station in a coverage area of
a wireless network formed by at least the first base station. The instant
geographic location based at least in part on an intersection of a line extending
outward from the first base station at the instant angular position with a circle
having a center defined by the first base station and a radius defined by the
radial distance.
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ln further embodiment, the process 1800 also includes correlating the
instant geographic location of the individual mobile station with a first sub-sector
geographic area in a first RF coverage map for the first sector antenna based at
least in part on a reference location for the first base station in the first RF
coverage map. The first RF coverage map formed by a plurality of sub-sector
geographic areas. Each sub-sector geographic area uniquely identified and
associated with a corresponding geographic location bin for the first RF coverage
map for storage of signal strength measurements from the first sector antenna
associated with the corresponding sub-sector geographic area. In this
embodiment, the process 1800 also includes sending the first signal strength
measurement to a first geographic location bin associated with the unique
identifier for the first sub-sector geographic area for storage in conjunction with
computation of a representative RF coverage level for populating the first subsector
geographic area in the first RF coverage map.
In another further embodiment, the process 1800 also includes correlating
the instant geographic location of the individual mobile station with a second subsector
geographic area in a second RF coverage map for the second sector
antenna based at least in part on a reference location for the first base station in
the second RF coverage map. The second RF coverage map formed by a
plurality of sub-sector geographic areas. Each sub-sector geographic area
uniquely identified and associated with a corresponding geographic location bin
for the second RF coverage map for storage of signal strength measurements
from the second sector antenna associated with the corresponding sub-sector
geographic area. In this embodiment, the process 1800 also includes sending
the second signal strength measurement to a second geographic location bin
associated with the unique identifier for the second sub-sector geographic area
for storage in conjunction with computation of a representative RF coverage level
for populating the second sub-sector geographic area in the second RF coverage
map.
With reference to FiGs. 17 and 19, yet another exemplary embodiment of
a process 1900 for estimating a geographic location of a mobile station within a
coverage area of a wireless network includes the process 1700 of FIG. 17 and
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continues at 902 where a radial distance of the individual mobile station from a
second base station serving the individual mobile station is determined. The
second base station including multiple sector antennas. The radial distance
based at least in part on a round trip measurement associated with elapsed time
between sending an outgoing signal from the second base station to the
individual mobile station and receiving a corresponding acknowledgement signal
from the individual mobile station at the second base station. The round trip
measurement related in calendar time to the first and second signal strength
measurements.
In another embodiment, the process 1900 also includes identifying an
instant geographic location of the individual mobile station in a coverage area of
a wireless network formed by at least the first and second base stations. The
instant geographic location based at least in part on an intersection of a line
extending outward from the first base station at the instant angular position with a
circle having a center defined by the second base station and a radius defined by
the radial distance.
In a further embodiment of the process 1900, a signal strength
measurement report from the individual mobile station comprising the first and
second signal strength measurements also includes a third signal strength
measurement. The third signal strength measurement representative of the
power characteristic of a third RF signal received by the individual mobile station
from a third sector antenna of the second base station. In this embodiment, the
process 1900 also includes correlating the instant geographic location of the
individual mobile station with a third sub-sector geographic area in a third RF
coverage map for the third sector antenna based at least in part on a reference
location for the second base station in the third RF coverage map. The third RF
coverage map formed by a plurality of sub-sector geographic areas. Each subsector
geographic area uniquely identified and associated with a corresponding
geographic location bin for the third RF coverage map for storage of signal
strength measurements from the third sector antenna associated with the
corresponding sub-sector geographic area. In the embodiment being described,
the process 1900 also includes sending the third signal strength measurement to
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a third geographic location bin associated with the unique identifier for the third
sub-sector geographic area for storage in conjunction with computation of a
representative RF coverage level for populating the third sub-sector geographic
area in the third RF coverage map.
With reference to FIG. 20, still another exemplary embodiment of a
process 2000 for estimating a geographic location of a mobile station within a
coverage area of a wireless network begins at 2002 where a radial distance of an
individual mobile station from a first base station serving the individual mobile
station is calculated. The first base station including multiple sector antennas.
The radial distance based at least in part on a round trip measurement
associated with elapsed time between sending an outgoing signal from the first
base station to the individual mobile station and receiving a corresponding
acknowledgement signal from the individual mobile station at the first base
station. Next, the process determines a signal strength report from the individual
mobile station provided to the first base station related in calendar time to the
round trip measurement includes a first signal strength measurement
representative of a power characteristic of a first RF signal received by the
individual mobile station from a first sector antenna of the first base station
(2004). The signal strength report not including other signal strength
measurements for other sector antennas of the first base station.
At 2006, an instant geographic location of the individual mobile station is
identified in a coverage area of a wireless network formed by at least the first
base station. The instant geographic location based at least in part on an
intersection of a circle having a center defined by the first base station and a
radius defined by the radial distance with a first sub-sector geographic area in a
first RF coverage map for the first sector antenna. The first RF coverage map
including a first reference location for the first base station to facilitate correlation
of the circle to the first RF coverage map. The first RF coverage map formed by
a plurality of sub-sector geographic areas. The first RF coverage map populated
with representative RF coverage levels associated with previous signal strength
measurements for the first sector antenna from one or more mobile stations in
previous signal strength reports comprising the corresponding previous signal
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strength measurement and at least one signal strength measurement from
another sector antenna of the first base station. The first sub-sector geographic
area in the first RF coverage map is populated with a first RF coverage level
representative of lacking previous signal strength measurements.
With reference to FIGs. 20 and 2 , still yet another exemplary embodiment
of a process 2100 for estimating a geographic location of a mobile station within
a coverage area of a wireless network includes the process 2000 of FIG. 20. In
this embodiment of the process 2100, each sub-sector geographic area is
uniquely identified and associated with a corresponding geographic location bin
for the first RF coverage map for storage of previous signal strength
measurements from the first sector antenna associated with the corresponding
sub-sector geographic area and a first geographic location bin associated with
the first RF coverage map and the first sub-sector geographic area is void of
previous signal strength measurements (2102).
In another embodiment, the process 2100 also includes identifying
multiple sub-sector geographic areas in the first RF coverage map intersecting
the circle associated with the first base station that are populated with the first RF
coverage level. In this embodiment, the first signal strength measurement is
compared to representative RF coverage levels associated with previous signal
strength measurements stored in corresponding geographic location bins for
corresponding sub-sector geographic areas of the first RF coverage map
neighboring each of the multiple sub-sector geographic areas. In the
embodiment being described, the first sub-sector geographic area is selected
from the multiple sub-sector geographic areas based at least in part on the
neighboring RF coverage level for the first sub-sector geographic area being
associated with previous signal strength measurements that are closer to the first
signal strength measurement than previous signal strength measurements
associated with neighboring RF coverage levels for other sub-sector geographic
areas of the multiple sub-sector geographic areas.
In yet another embodiment, the process 2100 also includes sending the
first signal strength measurement to a first geographic location bin associated
with the unique identifier for the first sub-sector geographic area for storage in
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conjunction with computation of a representative RF coverage ievei for
populating the first sub-sector geographic area in a second RF coverage map for
the first sector antenna. The second RF coverage map formed by a plurality of
sub-sector geographic areas. The second RF coverage map populated with
representative RF coverage levels associated with previous signal strength
measurements for the first sector antenna from one or more mobile stations in
previous signal strength reports.
With reference to FIGs. 20 and 22, another exemplary embodiment of a
process 2200 for estimating a geographic location of a mobile station within a
coverage area of a wireless network includes the process 2000 of FIG. 20 and
continues at 2202 with determining the signal strength report from the individual
mobile station provided to the first base station includes a second signal strength
measurement representative of the power characteristic of a second RF signal
received by the individual mobile station from a second sector antenna of a
second base station. The second base station including multiple sector
antennas. In this embodiment of the process 2200, the first RF coverage map
includes a second reference location for the second base station.
In another embodiment, the process 2200 also includes identifying
multiple sub-sector geographic areas in the first RF coverage map intersecting
the circle associated with the first base station that are populated with the first RF
coverage level. In this embodiment, geographic locations of the multiple subsector
geographic areas in the first RF coverage map are compared to a fixed
location for the second base station in relation to the first RF coverage map. In
the embodiment being described, the first sub-sector geographic area is selected
from the multiple sub-sector geographic areas based at least in part on the
geographic location for the first sub-sector geographic area being closer to the
fixed location for the second base station than the geographic locations for other
sub-sector geographic areas of the multiple sub-sector geographic areas.
In yet another embodiment, the process 2200 also includes correlating the
instant geographic location of the individual mobile station with a second subsector
geographic area in a second RF coverage map for the second sector
antenna based at least in part on a second reference location for the first base
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station in the second RF coverage map. The second RF coverage map formed
by a plurality of sub-sector geographic areas. Each sub-sector geographic area
uniquely identified and associated with a corresponding geographic location bin
for the second RF coverage map for storage of signal strength measurements
from the second sector antenna associated with the corresponding sub-sector
geographic area. In this embodiment, the process 2200 also includes sending
the second signal strength measurement to a second geographic location bin
associated with the unique identifier for the second sub-sector geographic area
for storage in conjunction with computation of a representative RF coverage level
for populating the second sub-sector geographic area in the second RF coverage
map for the second sector antenna.
With reference to FIG. 23, yet another exemplary embodiment of a
process 2300 for estimating a geographic location of a mobile station within a
coverage area of a wireless network begins at 2302 where a radial distance of an
individual mobile station from a first base station serving the individual mobile
station is calculated in response to detection of a dropped call for the mobile
station. The first base station including multiple sector antennas. The radial
distance based at least in part on a round trip measurement preceding detection
of the dropped call and in proximate time relation to detection of the dropped call.
The round trip measurement associated with elapsed time between sending an
outgoing signal from the first base station to the individual mobile station and
receiving a corresponding acknowledgement signal from the individual mobile
station at the first base station. Next, the process determines a signal strength
report from the individual mobile station provided to the first base station
preceding detection of the dropped call, in proximate time relation to detection of
the dropped call, and related in calendar time to the round trip measurement
includes a first signal strength measurement representative of a power
characteristic of a first RF signal received by the individual mobile station from a
first sector antenna of the first base station (2304).
At 2306, an instant geographic location of the individual mobile station is
identified in a coverage area of a wireless network formed by at least the first
base station. Identification of the instant geographic location is based at least in
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part on an intersection of a circle having a center defined by the first base station
and a radius defined by the radial distance with a first sub-sector geographic
area in a first RF coverage map for the first sector antenna. The first RF
coverage map including a first reference location for the first base station to
facilitate correlation of the circle to the first RF coverage map. The first RF
coverage map formed by a plurality of sub-sector geographic areas. The first RF
coverage map populated with representative RF coverage levels associated with
previous signal strength measurements for the first sector antenna from one or
more mobile stations in previous signal strength reports. The first sub-sector
geographic area in the first RF coverage map is populated with an RF coverage
level representative of a first signal strength value within a first predetermined
threshold of the first signal strength measurement.
In another embodiment, the process 2300 also includes identifying
multiple sub-sector geographic areas in the first RF coverage map intersecting
the circle associated with the first base station that are populated with RF
coverage levels representative of first signal strength values within the
predetermined threshold of the first signal strength measurement. In this
embodiment, the process determines the signal strength report from the
individual mobile station provided to the first base station includes a second
signal strength measurement representative of the power characteristic of a
second RF signal received by the individual mobile station from a second sector
antenna of a second base station. The second base station including multiple
sector antennas.
In a further embodiment, the process 2300 also includes comparing
geographic locations of the multiple sub-sector geographic areas in the first RF
coverage map to a fixed location for the second base station in relation to the first
RF coverage map. In this embodiment, the first sub-sector geographic area is
selected from the multiple sub-sector geographic areas based at least in part on
the geographic location for the first sub-sector geographic area being closer to
the fixed location for the second base station than the geographic locations for
other sub-sector geographic areas of the multiple sub-sector geographic areas.
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ln another further embodiment, the process 2300 also includes correlating
the circle associated with the first base station with a second RF coverage map
for the second sector antenna based at least in part on the second RF coverage
map including the first reference location for the first base station and a second
reference location for the second base station. The second RF coverage map
formed by a plurality of sub-sector geographic areas. The second RF coverage
map populated with representative RF coverage levels associated with previous
signal strength measurements for the second sector antenna from one or more
mobile stations in previous signal strength reports. In this embodiment, the
process 2300 also includes identifying a second sub-sector geographic area in
the second RF coverage map based at least in part on the circle associated with
the first base station intersecting at least one sub-sector geographic area in the
second RF coverage map populated with an RF coverage level representative of
a second signal strength value within a second predetermined threshold of the
second signal strength measurement. In the embodiment being described, the
second sub-sector geographic area in the second RF coverage map is correlated
with the first RF coverage map based at least in part on the first and second RF
coverage maps including the first and second reference locations for the first and
second base stations to identify the first sub-sector geographic area.
In yet another further embodiment, the process 2300 also includes
identifying multiple prospective geographic locations for the mobile station in a
second RF coverage map for the second sector antenna. The second RF
coverage map including the first reference location for the first base station and a
second reference location for the second base station. The second RF coverage
map formed by a plurality of sub-sector geographic areas. The second RF
coverage map populated with representative RF coverage levels associated with
previous signal strength measurements for the second sector antenna from one
or more mobile stations in previous signal strength reports. The multiple
prospective geographic locations based at least in part on the corresponding
sub-sector geographic areas in the second RF coverage map being populated
with an RF coverage level representative of a second signal strength value within
a second predetermined threshold of the second signal strength measurement.
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ln this embodiment, the process 2300 also includes correlating the multiple
prospective geographic locations for the mobile station in the second RF
coverage map with the first RF coverage map for the first sector antenna based
at least in part on the first and second RF coverage maps including the first
reference location for the first base station. In the embodiment being described,
identification of the instant geographic location is based at least in part on at least
one of the multiple prospective geographic locations intersecting the circle
associated with the first base station in the first RF coverage map.
With reference to FIG. 2, in one embodiment, the technique for estimating
the geographic location of the mobile station uses a round trip measurement
(e.g., RTD measurement) from a serving base station (i.e., serving cell) to
estimate the distance (d) of the mobile station from the serving base station.
Then, signal strength measurements from serving and/or neighboring sectors of
the serving base station to estimate an azimuth position (F) of the mobile station
in relation to an angular position reference extending outward from the serving
base station. Combining the sector coverage areas of the same base station
forms a corresponding cellular coverage area for the base station. The
individual sector coverage areas may also be referred to as cells in relation to
corresponding sector antennas. If so, the corresponding cells for sector
antennas associated with the same base station are still usually labeled as
sectors (e.g., a, b, g sectors or sectors 1, 2, 3). Normally, the sector antennas
associated with the same base station are mounted on the same cell tower (or
building). Hence, the radio wave travel from these sector antennas to a given
mobile station antenna will experience highly correlated losses (including path
loss and shadow fading). The algorithm described herein uses these RF
characteristics (i.e., highly correlated losses) to estimate an azimuth position of
the mobile station in relation to the serving based station based on the difference
of signal strength measurements from multiple sector antennas of the serving
base station.
In one embodiment, the algorithm for estimating a geographic location of a
mobile station within a coverage area of a wireless network begins with
estimating a distance (d) of the mobile station from the serving base station
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based on a round trip measurement, such as RTD. Next, the azimuth position
(F) of the mobile station in relation to the serving base station is estimated based
on signal strength measurements by the mobile station from multiple sector
antennas of the serving base station that are reported back by the mobile station
to the serving base station via the serving sector antenna. Combining the
distance (d) and azimuth position (F) forms a geographic location of the mobile
station in relation to the serving base station with respect to vector represented
by a displacement (i.e., distance (d)) and an angular position (i.e., azimuth
position (F)). This polar coordinate-type of geographic notation can be
converted to various other forms of geographic notation, including a
latitude/longitude notation, an address notation, or a geo-bin tile grid notation
associated with the coverage area for the wireless network. For example, the
geo-bin tile grid notation may use 50 meter by 50 meter tiles to represent the
coverage area for a sector antenna, base station, cluster of base stations, or the
overall wireless network. In other embodiments, any suitable tile size may be
used to provide a higher or lower resolution of the coverage area.
The approximation algorithm for estimating the geographic location of a
mobile station may be based on certain considerations regarding the mobile
received power (Pr) (i.e., signal strength measurements) from multiple sector
antennas where the sector antennas are located in close proximity to each other,
such as mounted on the same cell tower or on the same physical structure at
relatively the same elevation. For example, the mobile received power (Pr) is
received by the mobile station from multiple sector antennas of the serving base
station. The mobile station measures the signal strength of the mobile received
power (Pr) signals and may report back the corresponding signal strength
measurements in dBm.
Mobile received power (Pr) may be represented by the following equation:
Pr(d, F, Q) = Pt - PL(d) - X + Gt(d, F, Q) + Gr ( 1) ,
where d is a distance between the serving base station and the mobile station in
kilometers (km), F is an azimuth position of the mobile station in relation to an
angular position reference extending outward from the serving base station, Q is
an azimuth position at which the transmit portion of the corresponding sector
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antenna is oriented in relation to the angular reference position, Pt is a transmit
power for the corresponding sector antenna in dBm, and PL(d) is an average
path loss in dB for the corresponding sector antenna. The azimuth position Q of
the sector antenna is known and corresponds to its actual installation. Likewise,
the transmit power Pt for the sector antenna is known at the serving base station
based on known characteristics of the sector antenna or actual measurements by
the base station.
The average path loss PL(d) may be represented by the following
equation:
PL(d) = K 1 + K2 * log10(d) (2),
where K 1 and K2 are propagation parameters such that K 1 is function of
morphology, frequency, cell antenna height, and mobile antenna height and K2 is
function of cell antenna height.
With reference again to equation (1), X is a zero-mean Gaussian
distributed random variable (in dB) with standard deviation s approximately equal
to N(0, o). (in dB). X may be referred to as the shadowing fading effect. Gt(d,
F, Q) is the transmit antenna gain at the sector antenna in dB. Gr is receive
antenna gain at the mobile station in dB.
With reference to FIG. 3, Gt(d, F, Q) reflects that Gt is a function of mobile
distance (d) and an angle between the azimuth position (F) of the mobile station
and the azimuth position (Q) of the corresponding sector antenna. Note, the
distance (d), in combination with the sector antenna height, is used to estimate
an antenna tile and an antenna downtile. The azimuth position (F) of the mobile
station and the azimuth position (Q) of the corresponding sector antenna are
used to determine a horizontal gain portion of Gt, where the look angle is F - Q.
The distance (d) and the height (i.e., elevation) of the corresponding sector
antenna are used to determine a vertical gain component of Gt.
The signal strength measurements for mobile received power Pr may be
reported as received signal reference power (RSRP) measurements, reference
signal received quality (RSRQ) measurements, or Ec/io measurements. RSRQ
is the ratio of received signal reference power to total received power. Ec/lo is
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the ratio in B between the pilot energy accumulated over one PN chip period
("Ec") to the total power spectral density in the received bandwidth ("lo").
Mobile received power Pr1 and Pr2 from two sector antennas of the
serving base station in dBm may be represented by the following equations:
Pr1 (d, F, 1) = Pt1 - PL(d) - X + Gt1 (d, F, 01) + Gr (3),
Pr2 (d, F, Q2) = Pt2 - PL(d) - X + Gt2 (d, F, Q2) + Gr + e (4).
The path loss and shadowing fading effect from different sector antennas
of the same base station can be assumed to be equal where the sector antennas
are mounted on the same cell tower or building. The close proximity of the
sector antennas results in high correlation of between these components of the
mobile received power Pr1 and Pr2. For example, the differences of shadow
fading are expected to be very small and are counted by e in equation (4). As
mentioned above, d, Q1 and Q2 are known values.
Based on the foregoing, an estimate of the azimuth position (F) of the
mobile station may be based on the difference of mobile received power from the
two sector antennas (Pr1-Pr2) in dB. For example, (Pr1-Pr2) can be (RSRP1 -
RSRP2) or (RSRQ1-RSRQ2) in an LTE network. Similarly, (Pr1-Pr2) can be
(Ec/lo) 1 - (Ec/fo) 2 in a CDMA network. Even though the mobile received power
Pr1 and Pr2 are expressed in absolute received power format (i.e., dBm), the
estimation of mobile location does not require the knowledge of absolute
received power information. RSRQ for LTE and pilot Ec/lo for CDMA can be
used in the same manner as mentioned above.
Based on the foregoing, the difference between the mobile received power
Pr1 and Pr2 can be represented by the following equation:
(Pr1 - Pr2) = (Gt1 (F)- Gt2 (F) ) + (Pt1 - Pt2 ) (5),
where F can be substituted with a potential azimuth position Fhi for the mobile
station in the range of 0 to 360 degrees. The potential azimuth position F h that
results in the closest match between the right and left sides of equation (5) can
be used as estimated azimuth position of the mobile station.
Based on the foregoing, the azimuth position of the mobile station can be
represented by the following equation:
F(0)=| (Gt1 (F)- Gt2 (F) )+ (Pt1 - Pt2 )-(Pr1 - Pr2) | (6),
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where F can be substituted with a potential azimuth position <$>m for the mobile
station in the range of 0 to 360 degrees. The potential azimuth position <3>m that
minimizes F(Om) can be used as estimated azimuth position of the mobile
station.
This process can also be expressed in the following equation:
min (Gt1 (F)- Gt2 (F) )+ (Pt1 - Pt2 )-(Pr1 - Pr2) | (7).
Notably, the value selected for the initial potential azimuth position Fih in
equations (5) through (7) can be based at least in part on the knowledge of the
orientation and azimuth position of the serving sector antenna. Subsequent
values selected for the potential azimuth position Fih can be based on whether
the subsequent result is approaching or receding from the desired result.
Various techniques can also be used to select subsequent values for the
potential azimuth position Fih based on the magnitude of the difference between
the subsequent result and the desired result as well as the change in the
difference between consecutive subsequent results and the desired result.
With reference to FIG. 11, a bird's eye view of a coverage area of an
exemplary base station A in a wireless network shows an estimated geographic
location for a mobile station (UE) resulting from the process disclosed herein. A
geographic location for the mobile station (UE) based on GPS location is also
shown for comparison. The X and Y axes for the coverage area reflect distance
in meters from the base station A. Notably, the estimated geographic location is
close to the GPS location.
The base station A includes a first sector antenna oriented at 27 degrees
from north (i.e., an angular position reference representing 0 / 360 degrees) and
a second sector antenna oriented at 267 degrees. The mobile station reported
signal strength measurements from the first and second sector antennas at - 11
dB and -13 dB, respectively. The angular position of the mobile station was
estimated at 330.6 degrees using the process disclosed herein. The
measurements used to estimate the geographic location of the mobile station
were retrieved from per call measurement data (PCMD) for an active call
associated with the mobile station. For example, the PCMD data may be stored
by a wireless service provider during network operations for billing purposes.
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The process disclosed herein may use signal strength measurements and round
trip measurements captured and retained during network operations via any
suitable techniques without requiring additional network overhead for collection of
data to perform the estimate of the geographic location of the mobile station.
With reference to FIG. 12, various data and calculations associated with
the process for estimating the geographic location of a mobile station is provided
in a set of graphs. The upper left graph shows an azimuth gain parameter
characteristic for a first sector antenna of a serving base station. The first sector
antenna is oriented at 27 degrees from north (i.e., an angular position reference
representing 0 / 360 degrees). The middle left graph shows an azimuth gain
parameter characteristic for a second sector antenna of a serving base station.
The second sector antenna is oriented at 267 degrees from north. The azimuth
gain parameter characteristics may be manufacturer's specifications of power
measurements from the sector antennas from relatively close (e.g., 10 meters) to
the base station where little or no path loss is experienced. As shown, the first
and second sector antennas have the same azimuth gain characteristic merely
shifted by the orientation of the antennas. In other base station arrangements,
the sector antennas may have different azimuth gain characteristics.
The upper right graph shows an elevation gain parameter characteristic for
the first sector antenna. The first sector antenna is oriented at 2 degrees down
from horizontal (i.e., an elevation position reference representing 0 / 360
degrees). The middle right graph shows an elevation gain parameter
characteristic for the second sector antenna. The second sector antenna is also
oriented at 2 degrees down from horizontal. The elevation gain parameter
characteristics may be manufacturer's specifications of power measurements
from the sector antennas from relatively close (e.g., 10 meters) to the base
station where little or no path loss is experienced. As shown, the first and
second sector antennas have the same elevation gain characteristic. In other
base station arrangements, the sector antennas may have different elevation
gain characteristics. Also, the sector antennas may be oriented at different
angles from the horizontal in other base station arrangements.
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The lower left graph is a composite graph showing the difference between
gains for the first and second sector antennas. The composite graph takes the
azimuth and elevation gain characteristics into account to form a composite delta
gain characteristic. The composite graph reflects differences in relation to
varying azimuth position that follows the azimuth gain characteristics and a
relatively steady state component from the elevation gain characteristics because
the elevation tilt of the antennas is not changing. The following equation is used
to populate the composite graph:
(Gt1 (O)az + Gt1 e - Gt1 m ax) - (Gt2(0) + Gt2 ei - Gt2 max) (8),
where Gt1(<3>)az is the azimuth gain for the first sector antenna for a given
azimuth angle in relation to the angular position reference, Gt1 e is the elevation
gain for the first antenna associated with the elevation tilt, and Gt1 max is the
maximum gain for the first sector antenna. Similarly, Gt2(0) is the azimuth
gain for the second sector antenna for a given azimuth angle in relation to the
angular position reference, Gt2 e is the elevation gain for the second antenna
associated with the elevation tilt, and Gt2 m ax is the maximum gain for the second
sector antenna.
The lower right graph shows a function of the angular position of the
mobile station in relation to the delta antenna gain component, a delta transmit
parameter component, and a delta signal strength measurement component as
defined above in equation (7).
With reference to FIG. 4 , an exemplary embodiment of a process 400 for
estimating a geographic location of a mobile station within a coverage area of a
wireless network begins at 402 where a radial distance of a mobile station from a
base station serving the mobile station is determined. The base station includes
multiple sector antennas. The radial distance is based at least in part on a round
trip measurement associated with elapsed time between sending an outgoing
signal from the base station to the mobile station and receiving a corresponding
acknowledgement signal from the mobile station at the base station. At 404, a
current angular position of the mobile station in relation to the radial distance
from the serving base station is calculated. The current angular position is based
at least in part on a first signal strength measurement, a second signal strength
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measurement, and an angular position reference that extends outward from the
serving base station. The first and second signal strength measurements
representative of power characteristics of respective RF signals received by the
mobile station from corresponding first and second sector antennas of the
serving base station.
With reference to FIGs. 4 and 5, another exemplary embodiment of a
process 500 for estimating a geographic location of a mobile station within a
coverage area of a wireless network includes the process 400 of FIG. 4 and
continues at 502 where a current geographic location of the mobile station in a
coverage area of the wireless network is identified in a geographic notation. The
geographic notation is based at least in part on combining the radial distance and
current angular position of the mobile station relative to the serving base station.
In one embodiment, the radial distance and current angular position reflect a
polar coordinate-type of geographic notation in reference to the serving base
station. In other embodiments, the radial distance and current angular position
can be converted into various types of geographic notation, such as a
latitude/longitude notation, an address notation, or a geo-bin tile grid notation
associated with the coverage area for the wireless network.
In another embodiment, the process 500 also includes sending the current
geographic location of the mobile station in the geographic notation to a geolocation
storage node associated with the wireless network in a further
embodiment, the determining, calculating, identifying, and sending are performed
by the serving base station.
In yet another embodiment, the process 500 also includes receiving the
round trip measurement, first signal strength measurement, and second signal
strength measurement from the serving base station via the wireless network at a
geo-location service node associated with the wireless network. In this
embodiment, the current geographic location of the mobile station is sent in the
geographic notation to a geo-location storage device associated with the geolocation
service node. In the embodiment being described, the receiving,
determining, calculating, identifying, and sending are performed by the geolocation
service node.
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ln still another embodiment, the process 500 also includes receiving the
round trip measurement, first signal strength measurement, and second signal
strength measurement from the serving base station via the wireless network at a
network management node associated with the wireless network. In this
embodiment, the round trip measurement, first signal strength measurement, and
second signal strength measurement are stored at a measurements storage
device associated with the network management node. In the embodiment being
described, the round trip measurement, first signal strength measurement, and
second signal strength measurement are retrieved from the measurements
storage device in conjunction with the determining and calculating in this
embodiment, the process 500 also includes sending the current geographic
location of the mobile station in the geographic notation to a geo-location storage
device associated with the network management node. The receiving, storing,
retrieving, determining, calculating, identifying, and sending are performed by the
network management node in the embodiment being described.
With reference again to FIG. 4, in another embodiment of the process 400,
the round trip, first signal strength, and second signal strength measurements are
related in calendar time in a further embodiment, the radial distance and current
angular position of the mobile station relative to the serving base station are
indicative of a current geographic location of the mobile station in a coverage
area of the wireless network in relation to the calendar time associated with the
round trip, first signal strength, and second signal strength measurements.
In yet another embodiment of the process 400, the first sector antenna is
serving the mobile station and referred to as a serving sector antenna and the
second sector antenna is disposed near the first sector antenna and referred to
as a neighboring sector antenna in still another embodiment of the process 400,
the round trip measurement is measured by the serving base station. In a further
embodiment, the round trip measurement includes a RTD time measurement. In
still yet another embodiment of the process 400, the first and second signal
strength measurements are measured by the mobile station. In a further
embodiment, the first and second signal strength measurements include RSRP
measurements, RSRQ measurements, or Ec/lo measurements.
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ln another embodiment of the process 400, the calculating in 404 may
include retrieving first and second transmit parameter values from a storage
device associated with the wireless network. The first and second transmit
parameter values representative of power characteristics of respective
communication signals to be transmitted by the corresponding first and second
sector antennas. In this embodiment, the calculating in 404 may also include
determining a difference between the first and second transmit parameter values
to obtain a first angular position component.
In a further embodiment of the process 400, the calculating in 404 may
also include retrieving the first and second signal strength measurements from
the storage device. In this embodiment, the calculating in 404 may also include
determining a difference between the first and second signal strength
measurements to obtain a second angular position component.
In a yet further embodiment of the process 400, the calculating in 404 may
also include retrieving a first antenna elevation gain parameter value, a first
antenna maximum gain parameter value, and a first antenna azimuth gain
parameter characteristic from the storage device. The first antenna azimuth gain
parameter characteristic relating first antenna azimuth gain parameter values to
variable azimuth positions with respect to the angular position reference. The
variable azimuth positions representative of prospective azimuth positions of the
mobile station in relation to the angular position reference. The first antenna
azimuth gain parameter characteristic based at least in part on a first antenna
position value representative of a first azimuth position at which the first sector
antenna is oriented in relation to the angular position reference. In this
embodiment, a second antenna elevation gain parameter value, a second
antenna maximum gain parameter value, and a second antenna azimuth gain
parameter characteristic are also retrieved from the storage device. The second
antenna azimuth gain parameter characteristic relating second antenna azimuth
gain parameter values to the variable azimuth positions. The second antenna
azimuth gain parameter characteristic based at least in part on a second antenna
position value representative of a second azimuth position at which the second
sector antenna is oriented in relation to the angular position reference.
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ln the embodiment being described, an angular value (e.g., not exceeding
360) may be selected for the variable azimuth position. The first and second
antenna azimuth gain parameter characteristics may be used to identify the
corresponding first and second antenna azimuth gain parameter values for the
variable azimuth position associated with the selected angular value. In this
embodiment, the calculating in 404 may continue by determining a difference
between first and second transmit antenna gains for the selected angular value.
The difference may be determined by adding the first antenna azimuth gain
parameter value for the selected angular value to the first antenna elevation gain
parameter value and subtracting the first antenna maximum gain parameter
value to obtain the first transmit antenna gain, adding the second antenna
azimuth gain parameter value for the selected angular value to the second
antenna elevation gain parameter value and subtracting the second antenna
maximum gain parameter value to obtain the second transmit antenna gain, and
subtracting the second transmit antenna gain from the first transmit antenna gain
to obtain a third angular position component.
The angular value selected for the initial variable azimuth position can be
based at least in part on knowledge of which sector antenna is serving the mobile
station and the orientation and azimuth position of the serving sector antenna.
Subsequent values selected for the variable azimuth position can be based on
whether the subsequent result is approaching or receding from the desired result.
Various techniques can also be used to select subsequent values for the variable
azimuth position based on the magnitude of the difference between the
subsequent result and the desired result as well as the change in the difference
between consecutive subsequent results and the desired result.
For example, in a further embodiment of the process 400, the angular
value initially selected for the variable azimuth position may be between the first
and second antenna position values. In this embodiment, the initial angular
value may be representative of a mid-point between the first and second antenna
position values. In other words, if the first antenna is oriented to 120 degrees in
relation to the angular reference position, a second antenna may be oriented to
240 degrees, and 180 may be selected as the initial angular value for the
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variable azimuth position because it is at a midpoint between the first and second
sector antennas. The selection of other angular values for the variable azimuth
position can take into account whether the results are getting better or worse to
select angular values to obtain better results. The iterative selection of angular
values can be incremental or based on a factor of the difference between the
obtained result and the desired result.
In still another further embodiment of the process 400, the calculating in
404 also includes adding the first and third angular position components and
subtracting the second angular position component to form an arithmetic result.
In the embodiment being described, the arithmetic result is converted to an
absolute value. In this embodiment, if the absolute value is within a
predetermined threshold of a desired value (e.g., zero), the process 400
continues by identifying the angular value substituted for the variable azimuth
position as the current angular position for the mobile station. Otherwise, the
process 400 repeats the selecting with a different angular value, repeats the
determining of the difference between the first and second transmit gains to
obtain a new value for the third angular position component, repeats the adding
and subtracting to form the arithmetic result and the determining of the absolute
value, and continues the repeating until the absolute value is within the
predetermined threshold of the desired value.
In still yet another further embodiment of the process 400, the calculating
in 404 also includes adding the first and third angular position components and
subtracting the second angular position component to form an arithmetic result.
In this embodiment, the arithmetic result is converted to an absolute value. In the
embodiment being described, the process 400 repeats the selecting with a
different angular value, repeats the determining of the difference between the
first and second transmit gains to obtain a new value for the third angular position
component, repeats the adding and subtracting to form the arithmetic result and
the determining of the absolute value, and continues the repeating until the
absolute value is minimized. In this embodiment, the process 400 continues by
identifying the corresponding angular value substituted for the variable azimuth
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position for which the absolute value is minimized as the current angular position
for the mobile station.
In another further embodiment of the process 400, the calculating in 404
includes summing the first and third angular position components to form an
arithmetic result and comparing the arithmetic result to the second angular
position component. In this embodiment, if the arithmetic result is within a
predetermined range of the second angular position component, the process 400
continues by identifying the angular value substituted for the variable azimuth
position as the current angular position for the mobile station. Otherwise, the
process 400 repeats the selecting with a different angular value, repeats the
determining of the difference between the first and second transmit gains to
obtain a new value for the third angular position component, repeats the
summing of the first and third angular position components to form the arithmetic
result and the comparing of the arithmetic result to the second angular position
component, and continues the repeating until the arithmetic result is within the
predetermined range of the second angular position component.
With reference to FIG. 6, an exemplary embodiment of an apparatus for
estimating a geographic location of a mobile station 600 within a coverage area
of a wireless network 602 includes a distance module 604 and an angular
position module 606. The distance module 604 determines a radial distance of
the mobile station 600 from a base station 608 serving the mobile station 600.
The base station 608 includes multiple sector antennas (e.g., 610, 612, 614).
The radial distance is based at least in part on a round trip measurement
associated with elapsed time between sending an outgoing signal from the base
station 608 to the mobile station 600 and receiving a corresponding
acknowledgement signal from the mobile station 600 at the base station 608.
The angular position module 606 is in operative communication with the distance
module 604 and calculates a current angular position of the mobile station 600 in
relation to the radial distance from the serving base station 608. The current
angular position is based at least in part on a first signal strength measurement,
a second signal strength measurement, and an angular position reference that
extends outward from the serving base station 608. The first and second signal
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strength measurements representative of power characteristics of respective RF
signals received by the mobile station 600 from corresponding first and second
sector antennas 610, 612 of the serving base station 608. The current angular
position may also be based on additional signal strength measurements from
other sector antennas 614 (e.g., sector antenna N).
In this embodiment, the apparatus may also include a location module 616
in operative communication with the distance module 604 and angular position
module 606 for identifying a current geographic location of the mobile station 600
in a coverage area of the wireless network 602 in a geographic notation based at
least in part on combining the radial distance and current angular position of the
mobile station 600 relative to the serving base station 608. In one embodiment,
the radial distance and current angular position reflect a polar coordinate-type of
geographic notation in reference to the serving base station. In other
embodiments, the radial distance and current angular position can be converted
into various types of geographic notation, such as a latitude/longitude notation,
an address notation, or a geo-bin tile grid notation associated with the coverage
area for the wireless network.
In the embodiment being described, the apparatus may also include an
output module 618 in operative communication with the location module 616 for
sending the current geographic location of the mobile station 600 in the
geographic notation to a geo-location storage node 620 associated with the
wireless network 602. The geo-location storage node 620 may be internal or
external to the wireless network 602. In this embodiment, the apparatus may
include the serving base station 608. In this embodiment, the serving base
station 608 may include the distance module 604, angular position module 606,
location module 616, and output module 618.
With reference to FIG. 7, an exemplary embodiment of an apparatus for
estimating a geographic location of a mobile station 700 within a coverage area
of a wireless network 702 includes a distance module 704 and an angular
position module 706. The distance module 704 determines a radial distance of
the mobile station 700 from a base station 708 serving the mobile station 700.
The radial distance is based at least in part on a round trip measurement
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associated with elapsed time between sending an outgoing signal from the base
station 708 to the mobile station 700 and receiving a corresponding
acknowledgement signal from the mobile station 700 at the base station 708.
The angular position module 706 is in operative communication with the distance
module 704 and calculates a current angular position of the mobile station 700 in
relation to the radial distance from the serving base station 708. The current
angular position is based at least in part on a first signal strength measurement,
a second signal strength measurement, and an angular position reference that
extends outward from the serving base station 708. The first and second signal
strength measurements representative of power characteristics of respective RF
signals received by the mobile station 700 from corresponding first and second
sector antennas 710, 712 of the serving base station 708. The current angular
position may also be based on additional signal strength measurements from
other sector antennas 714 (e.g., sector antenna N).
In this embodiment, the apparatus may also include a location module 716
in operative communication with the distance module 704 and angular position
module 706 for identifying a current geographic location of the mobile station 700
in a coverage area of the wireless network 702 in a geographic notation based at
least in part on combining the radial distance and current angular position of the
mobile station 700 relative to the serving base station 708.
In the embodiment being described, the apparatus may include a geolocation
service node 722 associated with the wireless network 702 and in
operative communication with the serving base station 708. In this embodiment,
the geo-location service node 722 may include the distance module 704, angular
position module 706, and location module 716.
The geo-location service node 722 may also include an input module 724
and an output module 718. The input module 724 in operative communication
with the distance module 704 and angular position module 706 for receiving the
round trip measurement, first signal strength measurement, and second signal
strength measurement from the serving base station 708 via the wireless network
702. The output module 718 in operative communication with the location
module 716 for sending the current geographic location of the mobile station 700
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in the geographic notation to a geo-location storage device 726 associated with
the geo-location service node 722. The geo-location storage device 726 may be
internal or external to the geo-location service node 722. If the geo-location
storage device 726 is external to the geo-location service node 722, the geolocation
storage device 726 may be internal or external to the wireless network
702.
With reference to FIG. 8, an exemplary embodiment of an apparatus for
estimating a geographic location of a mobile station 800 within a coverage area
of a wireless network 802 includes a distance module 804 and an angular
position module 806. The distance module 804 determines a radial distance of
the mobile station 800 from a base station 808 serving the mobile station 800.
The radial distance is based at least in part on a round trip measurement
associated with elapsed time between sending an outgoing signal from the base
station 808 to the mobile station 800 and receiving a corresponding
acknowledgement signal from the mobile station 800 at the base station 808.
The angular position module 806 is in operative communication with the distance
module 804 and calculates a current angular position of the mobile station 800 in
relation to the radial distance from the serving base station 808. The current
angular position is based at least in part on a first signal strength measurement,
a second signal strength measurement, and an angular position reference that
extends outward from the serving base station 808. The first and second signal
strength measurements representative of power characteristics of respective RF
signals received by the mobile station 800 from corresponding first and second
sector antennas 810, 812 of the serving base station 808. The current angular
position may also be based on additional signal strength measurements from
other sector antennas 814 (e.g., sector antenna N).
In this embodiment, the apparatus may also include a location module 816
in operative communication with the distance module 804 and angular position
module 806 for identifying a current geographic location of the mobile station 800
in a coverage area of the wireless network 802 in a geographic notation based at
least in part on combining the radial distance and current angular position of the
mobile station 800 relative to the serving base station 808.
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ln the embodiment being described, the apparatus may include a network
management node 828 associated with the wireless network 802 and in
operative communication with the serving base station 808. In this embodiment,
the network management node 828 may include the distance module 804,
angular position module 806, and location module 816.
The network management node 828 may also include an input module
824, a measurements storage device 830, and an output module 818. The input
module 824 for receiving the round trip measurement, first signal strength
measurement, and second signal strength measurement from the serving base
station 808 via the wireless network 802. The measurements storage device 830
in operative communication with the input module 824, distance module 804, and
angular position module 806 for storing the round trip measurement, first signal
strength measurement, and second signal strength measurement. In this
embodiment, the distance module 804 retrieves the round trip measurement from
the measurements storage device 830 in conjunction with determining the radial
distance. Similarly, the angular position module 806 retrieves the first and
second signal strength measurements from the measurements storage device
830 in conjunction with calculating the current angular position. The output
module 818 in operative communication with the location module 816 for sending
the current geographic location of the mobile station 800 in the geographic
notation to the geo-location storage device 826. The geo-location storage device
826 may be internal or external to the network management node 828. If the
geo-location storage device 826 is external to the network management node
828, the geo-location storage device 826 may be internal or external to the
wireless network 802.
With reference to FIG. 9, an exemplary embodiment of an angular position
module 906 associated with the apparatus of FIGs. 6-8 may include a source
data communication sub-module 932 and a first angular component sub-module
938. The source data communication sub-module 932 for retrieving first and
second transmit parameter values from a storage device 936 associated with the
wireless network. The first and second transmit parameter values representative
of power characteristics of respective communication signals to be transmitted by
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the corresponding first and second sector antennas (e.g., 610, 612). In this
embodiment, the first angular component sub-module 938 is in operative
communication with the source data communication module 932 for determining
a difference between the first and second transmit parameter values to obtain a
first angular position component.
In a further embodiment of the angular position module 906, the source
data communication module may retrieve the first and second signal strength
measurements from the storage device 936. in this embodiment, the angular
position module 906 may also include a second angular component module 940
in operative communication with the source data communication module 932 for
determining a difference between the first and second signal strength
measurements to obtain a second angular position component.
In a yet further embodiment of the angular position module 906, the
source data communication sub-module 932 may also retrieve a first antenna
elevation gain parameter value, a first antenna maximum gain parameter value,
and a first antenna azimuth gain parameter characteristic from the storage device
936. The first antenna azimuth gain parameter characteristic relating first
antenna azimuth gain parameter values to variable azimuth positions with
respect to the angular position reference. The variable azimuth positions
representative of prospective azimuth positions of the mobile station 900 in
relation to the angular position reference. The first antenna azimuth gain
parameter characteristic based at least in part on a first antenna position value
representative of a first azimuth position at which the first sector antenna 910 is
oriented in relation to the angular position reference.
In this embodiment, the source data communication sub-module 932 may
also retrieve a second antenna elevation gain parameter value, a second
antenna maximum gain parameter value, and a second antenna azimuth gain
parameter characteristic from the storage device 936. The second antenna
azimuth gain parameter characteristic relating second antenna azimuth gain
parameter values to the variable azimuth positions. The second antenna
azimuth gain parameter characteristic based at least in part on a second antenna
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position value representative of a second azimuth position at which the second
sector antenna 9 2 is oriented in relation to the angular position reference.
In the embodiment being described, the angular position module 906 may
also include a third angular component sub-module 934 in operative
communication with the source data communication sub-module 932. The third
angular component sub-module 934 for selecting an angular value (e.g., not
exceeding 360) for the variable azimuth position. The third angular component
sub-module 934 using the first and second antenna azimuth gain parameter
characteristics to identify the corresponding first and second antenna azimuth
gain parameter values for the variable azimuth position associated with the
selected angular value.
In this embodiment, the third angular component sub-module 934 may
also determine a difference between first and second transmit antenna gains for
the selected angular value. The difference may be determined by adding the first
antenna azimuth gain parameter value for the selected angular value to the first
antenna elevation gain parameter value and subtracting the first antenna
maximum gain parameter value to obtain the first transmit antenna gain, adding
the second antenna azimuth gain parameter value for the selected angular value
to the second antenna elevation gain parameter value and subtracting the
second antenna maximum gain parameter value to obtain the second transmit
antenna gain, and subtracting the second transmit antenna gain from the first
transmit antenna gain to obtain a third angular position component.
The angular value selected for the initial variable azimuth position can be
based at least in part on knowledge of which sector antenna is serving the mobile
station and the orientation and azimuth position of the serving sector antenna.
Subsequent values selected for the variable azimuth position can be based on
whether the subsequent result is approaching or receding from the desired result.
Various techniques can also be used to select subsequent values for the variable
azimuth position based on the magnitude of the difference between the
subsequent result and the desired result as well as the change in the difference
between consecutive subsequent results and the desired result.
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For example, in a further embodiment of the angular position module 906,
the angular value initially selected for the variable azimuth position by the third
angular component sub-module 934 may be between the first and second
antenna position values. In this embodiment, the initial angular value may be
representative of a mid-point between the first and second antenna position
values. In other words, if the first antenna is oriented to 20 degrees in relation
to the angular reference position, a second antenna may be oriented to 240
degrees, and 180 may be selected as the initial angular value for the variable
azimuth position because it is at a midpoint between the first and second sector
antennas. The selection of other angular values for the variable azimuth position
can take into account whether the results are getting better or worse to select
angular values to obtain better results. The iterative selection of angular values
can be incremental or based on a factor of the difference between the obtained
result and the desired result.
In a yet further embodiment, the angular position module 906 may include
an arithmetic sub-module 942 and a control sub-module 944. In this
embodiment, the arithmetic sub-module 942 is in operative communication with
the first, second, and third angular component modules 938, 940, 934 for adding
the first and third angular position components and subtracting the second
angular position component to form an arithmetic result. In the embodiment
being described, the arithmetic sub-module 942 converts the arithmetic result to
an absolute value. The control sub-module 944 is in operative communication
with the arithmetic sub-module 942 and the third angular component sub-module
934 for identifying the angular value substituted for the variable azimuth position
as the current angular position for the mobile station 900 if the arithmetic result is
within a predetermined threshold of a desired value (e.g., zero). Otherwise, the
control sub-module 944 may causes the third angular component module 934 to
repeat the selecting with a different angular value and the determining of the
difference between the first and second transmit gains to obtain a new value for
the third angular position component, causes the arithmetic sub-module 942 to
repeat the adding and subtracting to form the arithmetic result and the
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determining of the absolute value, and causes the repeating to continue until the
arithmetic result is within the predetermined threshold of the desired value.
In an alternate further embodiment, the arithmetic sub-module 942 may be
in operative communication with the first, second, and third angular component
modules 938, 940, 934 for adding the first and third angular position components
and subtracting the second angular position component to form an arithmetic
result. In the embodiment being described, the arithmetic sub-module 942
converts the arithmetic result to an absolute value. In this embodiment, the
control sub-module 944 may be in operative communication with the arithmetic
sub-module 942 and the third angular component module 934 for causing the
third angular component sub-module 934 to repeat the selecting with a different
angular value and the determining of the difference between the first and second
transmit gains to obtain a new value for the third angular position component,
causing the arithmetic sub-module 942 to repeat the adding and subtracting to
form the arithmetic result and the determining of the absolute value, and causing
the repeating to continue until the absolute value is minimized. In the
embodiment being described, the control sub-module 944 identifies the
corresponding angular value substituted for the variable azimuth position for
which the absolute value is minimized as the current angular position for the
mobile station 900.
In another alternate further embodiment, the arithmetic sub-module 942
may be in operative communication with the first, second, and third angular
component modules 938, 940, 934 for summing the first and third angular
position components to form an arithmetic result. In the embodiment being
described, the arithmetic sub-module 942 compares the arithmetic result to the
second angular position component 940. In this embodiment, the control submodule
944 may be in operative communication with the arithmetic sub-module
942 and the third angular component sub-module 934 for identifying the angular
value substituted for the variable azimuth position as the current angular position
for the mobile station if the arithmetic result is within a predetermined range of
the second angular position component. Otherwise, the control sub-module 944
causes the third angular component module 934 to repeat the selecting with a
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different angular value and the determining of the difference between the first
and second transmit gains to obtain a new value for the third angular position
component, causes the arithmetic sub-module 942 to repeat the summing of the
first and third angular position components to form the arithmetic result and the
comparing of the arithmetic result to the second angular position component, and
cause the repeating to continue until the arithmetic result is within the
predetermined range of the second angular position component.
With reference to FIG. 10, an exemplary embodiment of a non-transitory
computer-readable medium storing program instructions that, when executed by
a computer, cause a corresponding computer-controlled device to perform a
process 1000 for estimating a geographic location of a mobile station within a
coverage area of a wireless network. In one embodiment, the process 1000
begins at 1002 where a radial distance of a mobile station from a base station is
calculated. The base station including multiple sector antennas. The radial
distance is based at least in part on a round trip measurement associated with
elapsed time between sending an outgoing signal from the base station to the
mobile station and receiving a corresponding acknowledgement signal from the
mobile station at the base station. At 1004, the process determines a signal
strength report from the mobile station provided to the base station includes a
signal strength measurement representative of a power characteristic of an RF
signal received by the mobile station from a sector antenna of the base station.
Next, an instant geographic location of the mobile station in a coverage area of
the wireless network may be identified (1006).
In various embodiments, the program instructions stored in the nontransitory
computer-readable memory, when executed by the computer, may
cause the computer-controlled device to perform various combinations of
functions associated with the various embodiments of the processes 400, 500,
1700, 1800, 1900, 2000, 2100, 2200, and 2300 for estimating a geographic
location of a mobile station described above with reference to FIGs. 4, 5, and 17-
23. In other words, the various embodiments of the processes 400, 500, 1700,
1800, 1900, 2000, 2100, 2200, and 2300 described above may also be
implemented by corresponding embodiments of the process 1000 associated
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with the program instructions stored in the non-transitory computer-readable
memory.
Likewise, in various embodiments, the program instructions stored in the
non-transitory computer-readable memory, when executed by the computer, may
cause the computer-controlled device to perform various combinations of
functions associated with the various embodiments of the apparatus for
estimating a geographic location of a mobile station described above with
reference to FIGs. 6-8 and the angular position module 906 described above with
reference to FIG. 9.
For example, the computer-controlled device may include a base station
(see FIG. 6, 608), a geo-location service node (see FIG. 7, 722), a network
management node (see FfG. 8, 828), or any suitable communication node
associated with the wireless network. Any suitable module or sub-module
described above with reference to FiGs. 6-9 may include the computer and nontransitory
computer-readable memory associated with the program instructions.
Alternatively, the computer and non-transitory computer-readable memory
associated with the program instructions may be individual or combined
components that are in operative communication with any suitable combination
of the modules and sub-modules described above with reference to FIGs. 6-9
The above description merely provides a disclosure of particular
embodiments of the invention and is not intended for the purposes of limiting the
same thereto. As such, the invention is not limited to only the above-described
embodiments. Rather, it is recognized that one skilled in the art could conceive
alternative embodiments that fall within the scope of the invention.

We claim
. A method for mapping an operating parameter in a coverage area of a
wireless network, comprising:
obtaining parameter measurements for a select operating parameter
associated with one or more mobile stations operating in at least a select portion
of a network coverage area for a wireless network, the parameter measurements
having been measured during a select calendar timeframe, the network coverage
area formed by a plurality of base stations, each base station defining a cellular
coverage area within the network coverage area, the select portion of the
network coverage area formed by at least one base station, each at least one
base station including multiple sector antennas, each sector antenna defining a
sector coverage area within the cellular coverage area for the corresponding
base station; and
for each obtained parameter measurement, estimating an instant
geographic location of the corresponding mobile station in relation to the at least
one base station serving the corresponding mobile station, each instant
geographic location based at least in part on a round trip measurement and at
least one signal strength measurement associated with the corresponding mobile
station, each round trip measurement associated with the at least one base
station serving the corresponding mobile station, each round trip measurement
and corresponding at least one signal strength measurement related in calendar
time to the corresponding parameter measurement.
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2 . The method of claim , further comprising:
processing the obtained parameter measurements for each instant
geographic location to obtain a representative parameter value for the
corresponding instant geographic location; and
populating a coverage area map for the wireless network with the
representative parameter values based at least in part on the instant geographic
location associated with the corresponding representative parameter value, the
coverage area map including at least the select portion of the network coverage
area.
3. The method of claim 2 wherein the representative parameter values are
obtained by one or more of filtering the corresponding parameter measurements
to remove unreliable measurements, averaging the corresponding parameter
measurements, determining a median value for the corresponding parameter
measurements, and selecting a preferred parameter measurement from the
corresponding parameter measurements based at least in part on a preferred
calendar time for the corresponding representative parameter value.
4. The method of claim 2 wherein the coverage area map is a radio
frequency (RF) coverage area map, a handoff zone coverage area map, a data
usage coverage area map, a signaling usage coverage area map, a population
coverage area map for directory number identification, device identification,
device type, or application program, a quality of service coverage area map for
throughput, packet loss, or packet delay, or a user profile coverage area map.
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5. The method of claim 1 wherein at least the select portion of the network
coverage area is represented in a coverage area map for the wireless network by
a plurality of sub-sector geographic areas, each sub-sector geographic area
uniquely identified and associated with at least a portion of the sector coverage
area for at least one sector antenna, the method further comprising:
correlating each estimated instant geographic location with a sub-sector
geographic area of the plurality of sub-sector geographic areas, each sub-sector
geographic area adapted to represent more than one instant geographic location,
the correlating based at least in part on a reference location in the coverage area
map for the at least one base station serving the mobile station associated with
the corresponding instant geographic location.
6. The method of claim 5, further comprising:
processing the obtained parameter measurements for each sub-sector
geographic area to obtain a representative parameter value for the
corresponding sub-sector geographic area; and
populating the coverage area map with the representative parameter
values based at least in part on the sub-sector geographic area associated with
the corresponding representative parameter value.
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7. The method of claim 5 wherein each sub-sector geographic area is
associated with a corresponding geographic location bin for storage of parameter
measurements associated with the instant geographic locations represented by
the corresponding sub-sector geographic, the method further comprising:
storing each obtained parameter measurement in a geographic location
bin associated with the sub-sector geographic area representing the instant
geographic location associated with the corresponding parameter measurement;
processing the parameter measurements stored in each geographic
location bin to obtain a representative parameter value for the corresponding
geographic location bin; and
populating the coverage area map with the representative parameter
values based at least in part on the geographic location bin associated with the
corresponding representative parameter value and the sub-sector geographic
area associated with the corresponding geographic location bin.
8. An apparatus for mapping an operating parameter in a coverage area of a
wireless network, comprising:
an input module for obtaining parameter measurements for a select
operating parameter associated with one or more mobile stations operating in at
least a select portion of a network coverage area for a wireless network, the
parameter measurements having been measured during a select calendar
timeframe, the network coverage area formed by a plurality of base stations,
each base station defining a cellular coverage area within the network coverage
area, the select portion of the network coverage area formed by at least one
base station, each at least one base station including multiple sector antennas,
each sector antenna defining a sector coverage area within the cellular coverage
area for the corresponding base station; and
a location module in operative communication with the input module for
estimating an instant geographic location of the corresponding mobile station for
each obtained parameter measurement in relation to the at least one base
station serving the corresponding mobile station, each instant geographic
location based at least in part on a round trip measurement and at least one
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signal strength measurement associated with the corresponding mobile station,
the round trip and at least one signal strength measurements obtained via the
input module, each round trip measurement associated with the at least one
base station serving the corresponding mobile station, each round trip
measurement and corresponding at least one signal strength measurement
related in calendar time to the corresponding parameter measurement.
9. The apparatus of claim 8, further comprising:
a processing module in operative communication with the input module
and location module for processing the obtained parameter measurements for
each instant geographic location to obtain a representative parameter value for
the corresponding instant geographic location; and
a mapping module in operative communication with the processing
module for populating a coverage area map for the wireless network with the
representative parameter values based at least in part on the instant geographic
location associated with the corresponding representative parameter value, the
coverage area map including at least the select portion of the network coverage
area.
10. The apparatus of claim 8 wherein at least the select portion of the network
coverage area is represented in a coverage area map for the wireless network by
a plurality of sub-sector geographic areas, each sub-sector geographic area
uniquely identified and associated with at least a portion of the sector coverage
area for at least one sector antenna, the apparatus further comprising:
a correlation module in operative communication with the location module
for correlating each estimated instant geographic location with a sub-sector
geographic area of the plurality of sub-sector geographic areas, each sub-sector
geographic area adapted to represent more than one instant geographic location,
the correlating based at least in part on a reference location in the coverage area
map for the at least one base station serving the mobile station associated with
the corresponding instant geographic location.