CELLULAR SERVICE WITH IMPROVED SERVICE AVAILABILITY
BACKGROUND
[0001] Mobile wireless devices, such as cellular telephones, are widely used. In addition
to allowing users to carry on voice telephone calls, mobile wireless devices allow users to
access data services through which users can obtain many forms of digital content. Users
may surf the Internet, download video clips or send electronic messages, to name a few of
the possible uses of mobile wireless devices.
[0002] Frequently, mobile wireless devices connect to data sources through cellular
networks. The cellular networks include base stations distributed throughout an area in
which cellular service is provided. In urban areas, the base stations may be spaced by
about 300 meters. In rural areas, the base stations may be spaced by a distance of between
about 1.5 and 2 Kilometers. Regardless of the spacing, the geographic regions around the
base stations define "cells," with mobile devices in each cell connecting to the base station
in that cell.
[0003] A mobile device, to connect to a data source, first makes a connection to a base
station in its cell. The base station provides access to a network, such as the Internet, over
which the mobile wireless device can then access data sources that are also coupled to the
network. As mobile devices move from one cell to another, the base stations in those cells
communicate to "handover" responsibility for continuing communication with the mobile
device, such that communication is not lost even as the mobile device move out of the cell.
[0004] To support download of digital content and a growing number of other services,
cellular networks have been upgraded to support higher bandwidth communications. State
of the art networks communicating using a 3G wireless standard can support data
communications at rates in excess of 1 Megabit per second (Mbps). However, it has been
found that when many users are in the same cell - such as may occur in an urban area - a
base station may become overloaded.
[0005] Overload can occur if the cumulative bandwidth that would be consumed if all of
the devices communicated at the maximum data rate of the 3G service exceeds the
capacity of the base station. When the base station is overloaded, each device is only able
to communicate at a fraction of the rated bandwidth of the cellular service or admission to
the network is rejected, causing frustration to the user. There are also common situations
when mobile devices are at the edge of coverage of a cell where either less spectrum is
available (such was mentioned earlier) or there is enough spectrum but providing
broadband data requires high transmitted power. This is particularly problematic for
portable devices (slate, Netbook, or a smart phone) where even 2 Mbps can drain the
battery in less than 30 minutes at the edge of coverage. The same problem arises in
building with link loss of 15 dB or higher; this can easily occur in buildings with metal
tinted glass windows if devices are even a few meters away from the window, for instance.
SUMMARY
[0006] An improved experience for users of a cellular service is provided by providing a
mechanism to, upon detection of a trigger condition —such as (1) an overloaded base
station, (2) degradation in performance, (3) low battery level, and/or (3) increase in RF
power from the mobile device —alter the frequency spectrum used by the base station to
communicate with selected wireless devices. The frequency spectrum may be altered by
moving to a lower licensed spectrum or unlicensed use of TV whitespace. Wireless
devices may be selected based on being associated with users who agree to use of an
alternative frequency spectrum. The users who continue to communicate with the base
station using the assigned frequency spectrum of the base station may experience
improved bandwidth for their communications because the load on the base station may be
reduced. Though, users communicating over the alternative frequency spectrum may
receive lower bandwidth for their communications.
[0007] Incentives may be offered to users to encourage then to accept lower bandwidth
communication. The incentives may be financial, such as a discount or rebate associated
with their cellular service. Though, other forms of incentives, such as free download of
digital content at a future time may be offered.
[0008] Users contacted with an offer to communicate using the alternative frequency
spectrum, and in some embodiments offered incentives to agree to use the alternative
frequency spectrum, may be identified in any suitable way. For example, users offered the
option to accept a lower bandwidth connection using the alternative frequency spectrum
may be identified by time of first access to the cellular service or by range from the base
station. If selected based on time, users attempting access to a network through a cellular
base station that is already overloaded or is already communicating with wireless devices
that in the aggregate consume more than a threshold percentage of bandwidth of the base
station, may be offered an incentive to connect at a lower bandwidth. Alternatively or
additionally, if selected by range, those users closest to a base station when an overload
condition is detected may be offered an incentive.
[0009] The foregoing is a non-limiting summary of the invention, which is defined by the
attached claims.
BRIEF DESCRIPTION OF DRAWINGS
[0010] The accompanying drawings are not intended to be drawn to scale. In the
drawings, each identical or nearly identical component that is illustrated in various figures
is represented by a like numeral. For purposes of clarity, not every component may be
labeled in every drawing. In the drawings:
[0011] FIG. 1 is a conceptual sketch of a communication system according to some
embodiments operating at a first time;
[0012] FIG. 2 is a conceptual sketch of a cell of the communication system of FIG. 1
operating at a second time;
[0013] FIG. 3 is a sketch of a user interface of a mobile device operating in the
communication system of FIG. 1;
[0014] FIG. 4 is a conceptual illustration of a handover between base stations in the
communication system of FIG. 1;
[0015] FIG. 5 is a flow chart of a method of operation of a base station in the
communication system of FIG. 1;
[0016] FIG. 6 is a flow chart of a method of operation of a mobile device associated with
a base station in the communication system of FIG. 1; and
[0017] FIG. 7 is a functional block diagram of a base station in the communication system
of FIG. 1
DETAILED DESCRIPTION
[0018] The inventors have recognized and appreciated that the frustrations some cellular
users experience when they seemingly are unable to access high speed data services to
which they have subscribed is sometimes the result of overloaded base stations. The
inventors have further recognized and appreciated that these frustrations may be lessened
by encouraging some users to communicate with a cellular base station using an
alternative frequency spectrum. White space within the digital TV spectrum provides a
suitable alternative frequency spectrum, particularly for users who are within a relatively
short range of a base station.
[0019] Accordingly, in some embodiments, cellular base stations may be equipped to
identify times when at least some users are offered an option to connect through an
alternative frequency spectrum. Various approaches for determining when such offers are
made and for selecting the users to receive such offers.
[0020] To determine the time when such offers are made, the base station may monitor
aggregate bandwidth usage of all mobile devices in its cell. When aggregate usage
approaches a threshold, the base station may be triggered to select users willing to accept
communication using the alternative frequency spectrum.
[0021] Users willing to accept communications using an alternative frequency spectrum
may be selected in any suitable way. For example, the base station may send an offer to
the user, which the user's mobile device may display. In some embodiments, users may
pre-agree, as part of a service contract or other contractual exchange with the cellular
service provider, to accept communications over the alternative frequency spectrum.
Though, embodiments are also possible where agreement may be implied - such as when
the allocated frequency for the base station is so congested that, even if the user were
admitted to communicate with the base station using the allocated frequency spectrum, the
user would receive such a small amount of bandwidth for communication with the base
station that the user could be inferred to prefer to use the alternative frequency spectrum.
[0022] In some scenarios, a connection over the alternative frequency spectrum may not
provide as high a bandwidth as a rated or target bandwidth for the cellular service. In
some instances, the bandwidth achieved using the alternative frequency spectrum may be
less than what could be achieved with communications using the assigned spectrum for the
base station, even with congestion. In such scenarios, absent other incentives, the offer to
use the alternative frequency spectrum may not result in a sufficient number of users
accepting the offer to reduce congestion on the base station. Accordingly, users offered the
option to connect on an alternative spectrum also may be offered incentives to agree to the
alternative frequency .
[0023] The offered incentives may be financial, may relate to services provided by the
cellular service provider or may be some other type of incentive. The nature of incentives
also may depend on the nature of a service agreement between a user and the cellular
service provider. As one example, if a user has a service agreement under which the user
pays for data transfer, the user may be charged at a lower rate, or not at all, for data
transfers made using the alternative frequency spectrum.
[0024] Users that receive an offer to communicate using the alternative frequency
spectrum may be identified in any suitable way. For example, users may be identified
based on total available bandwidth for the base station already consumed by other mobile
devices at the time a new mobile device associates with the base station or, to preserve a
consistent level of service as mobile devices move from cell to cell, at the time the mobile
device associates with the cellular network. If total available bandwidth exceeds a
threshold, all new users may be offered the option to use the alternative frequency
spectrum. Alternatively or additionally, the users that receive an offer may be identified
based on their usage at the time available bandwidth for the base station consumed
exceeds the threshold. For example, those users who are engaging in low bandwidth
communications, such as sending SMS messages, may be identified to receive the offer.
[0025] Alternatively or additionally, users may be identified to receive the offer based on
location relative to the base station. Users who are closer to the base station may be
preferentially receive the offer. As a specific example, users within a radius of 50 meters,
may be identified to receive the offer. Because signal strengths for communications
between nearby devices may be greater than if comparable communication equipment is
used to communicate at a longer range, the devices that are closer together can
communicate with less errors. Lower errors, in turn, results in greater percentage of the
possible throughput for a channel being achieved for devices that are communicating at
shorter ranges. Even though available throughput may be less using the alternative
spectrum, achieving a greater percentage of that throughput may result in adequate
communication, meaning that users close to the base station may experience less
degradation in performance upon switching to the alternative frequency spectrum than
users further away.
[0026] Turning to FIG. 1, an example of a communication system 100 according to some
embodiments is illustrated. FIG. 1 illustrates a cellular communication system 100. In
this example, two cells, cells 110A and HOB are illustrated. Though, one of skill in the
art will appreciate that a cellular communication system may have numerous cells but that
only two cells are shown for simplicity.
[0027] Each of the cells 110A and HOB includes a base station. Cell 110A includes base
station 120A. Cell HOB includes base station 120B. Each base station is shown to
contain a controller portion, 122A and 122B, respectively, and a transceiver portion 124A
and 124B, respectively. Transceiver portions 124A and 124B transmit and receive signals
carrying communications between the base station and mobile devices of users within the
respective cells. For example, transceiver portion 124A exchanges wireless signals with
mobile devices 140A, 142A and 144A, associated with users 130A, 132A and 134A,
respectively. Transceiver portion 124B exchanges wireless communications with mobile
devices 140B and 142B, which are associated with users 130B and 132B, respectively.
[0028] Communications exchanged between a base station and a mobile device may be
controlled by the controller portions 122A and 122B of the base stations. According to
some embodiments, controller portions 122A and 122B may exchange control messages
with mobile devices within their cells to determine which mobile devices are admitted to
communicate through the base station and to control other parameters of communication.
Such control messages may be of the type that is conventionally controlled in a cellular
communication system, though any suitable control scheme may be used. In addition,
controller portions 1 A and 122B may exchange control messages with mobile devices
to specify a frequency spectrum that the mobile devices use for communications with the
base station.
[0029] In a conventional cellular communication system, a cellular service provider may
have an assigned frequency spectrum that is a portion of a frequency band allocated for
use for cellular communications. Communications with mobile devices may be based on
wireless communications occurring in that assigned frequency spectrum, though different
devices may use different specific frequencies within the spectrum. Each of the base
stations may communicate over such an assigned cellular communication spectrum. In
accordance with some embodiments of the invention, each of the base stations additionally
may be configured for communicating with mobile devices using an alternative frequency
spectrum.
[0030] The specific frequency ranges associated with the assigned frequency spectrum
and alternative frequency spectrum are not critical to the invention. However, in some
embodiments, communication system 100 is configured to offer 3G cellular
communication service. Accordingly, the assigned spectrum may be in the frequency
range allocated for 3G communication.
[0031] The alternative frequency spectrum may encompass any suitable frequency range.
Though, in some embodiments, the alternative frequency spectrum does not encompass
frequencies assigned to the base station, and therefore does not overlap with the licensed
frequency spectrum. In some embodiments, the alternative frequency spectrum may be a
portion of a frequency spectrum allocated to another type of service other than cellular
communication but unused in the geographic region of communication system 100. In
some embodiments, the alternative frequency spectrum is white space within a frequency
spectrum allocated for digital TV communication. Accordingly, transceiver portions
124A and 124B may be adapted to communicate both within the 3G frequency spectrum
and the digital TV frequency spectrum. Controllers 122A and 122B may be adapted to
control the operation of transceivers 124A and 124B such that communications with
different ones of the mobile devices within each cell communicate using either frequencies
within the assigned frequency spectrum or frequencies within the alternative frequency
spectrum.
[0032] In order to coordinate communications with the mobile devices, controller portions
122A and 122B may cause transceiver portions 124A and 124B, respectively, to exchange
control messages with the mobile devices. These control messages may perform functions
associating with selecting mobile devices to communicate in the alternative frequency
spectrum. Such functions may include instructing a mobile device to display an offer to a
user to communicate using the alternative frequency spectrum, receiving from the mobile
device a control message representing a user's response to the display of the offer or
commanding the mobile device to communicate using either the alternative frequency
spectrum or the assigned frequency spectrum for the cellular communication system.
These control messages may be sent over a control channel associated with the cellular
communication system. Though, the format and protocol used for exchanging such
control messages is not critical to the invention and any suitable protocol may be used.
[0033] Once a mobile device is admitted for communication through a base station based
on exchanged control messages, the mobile device may utilize the communication system
to send and receive information through communications with the base station. The nature
of the information communicated between mobile devices and the base stations also is not
critical to the invention. In some scenarios, the information communicated will be high
speed digital communications such as may be used to represent movie clips or other audio
visual information or that may be used to represent graphical content on web pages.
Though, digital data, which may be communicated through communication system 100,
may represent many other items. Moreover, it is not a requirement of the invention that
the mobile devices be accessing digital content. For example, communications may entail
voice communications. Accordingly, the nature of the communications is not critical to
the invention.
[0034] Regardless of the nature of communications, at any given time, the number of
users within a cell and the nature of their usage may be such that the base station in the
cell may be regarded as not congested and may operate in a normal mode. For example,
cell 110A contains three users 130A, 132A and 134A. Those three users, in the example
of FIG. 1, may not be using their respective mobile devices in such a way that, in the
aggregate, they consume the total available bandwidth of base station 120A.
[0035] As a specific numerical example, base station 120A may be constructed to support
communications that in the aggregate involves 100 megabits per second (Mbps). During a
first time, as illustrated in FIG. 1, mobile devices 140A, 142A and 144A may subscribe to
cellular service in accordance with data plans that each provides five Mbps data rates.
Accordingly, even if mobile devices 140A, 142A and 144A are communicating at the
maximum data rates of their services, they will collectively consume less than 100 Mbps
and will not overload base station 120. Thus, in this scenario, controller 120A has
sufficient bandwidth to support communications with all the mobile devices within cell
110A using the assigned frequency spectrum.
[0036] Likewise, controller 120B in the state illustrated in FIG. 1, may have sufficient
bandwidth to support communications on the assigned frequency spectrum with all of the
devices within cell HOB. In the state illustrated in FIG. 1, all of the illustrated mobile
devices may be communicating as in a conventional 3G communication system.
[0037] Congestion may occur if the mobile devices of all the users within a cell, in the
aggregate, consume or are projected to consume more than the total available bandwidth
the base station has for communication using the assigned frequency spectrum. FIG. 2
illustrates cell 110B at a second time at which such congestion may occur.
[0038] Between the first time, illustrated in FIG. 1, and the second time, illustrated in
FIG. 2, additional users have entered cell HOB. For simplicity of illustration, FIG. 2
shows three users, users 130B, 132B and 134B, in cell HOB. This number of users is
shown for simplicity of illustration. One of skill in the art will recognize that more than
three users may, in many embodiments of a cellular communication system, operate
within a cell without overloading a base station. Nonetheless, in the simple example of
FIG. 2, adding a third user, user 134B, represents an increase in the load on base station
120B. When the load on base station 120B increases to the point that the base station is
congested, controller portion 122B may enter a mode in which it attempts to switch one or
more users to communicate using an alternative frequency spectrum. In this way,
bandwidth may be offloaded from the assigned frequency spectrum to the alternative
frequency spectrum.
[0039] The addition of user 134B at a second time represented by FIG. 2 may be taken as
an example of a triggering event for a base station entering an offload mode of operation.
Other events may trigger controller portion 122B to enter a mode of offloading
communications from the assigned frequency spectrum. For example, a time of day
known from historical data to result in congestion may be regarded as a triggering event.
An aggregate number of users within a cell exceeding a threshold or an aggregate number
of users with a certain type of data plan, such as a data plan having a service guarantee for
a relatively high bandwidth, may each be regarded as triggering events in some
embodiments. As a further example, it is not a requirement tha the triggering event be
based on actual usage. In some embodiments, a triggering event may be based on a
projected load.
[0040] Regardless of the triggering event, controller portion 122B may then select one or
more users to communicate using the alternative frequency spectrum. In some
embodiments, the selected users may be those who agree to use the alternative frequency
spectrum. For example, base station 122B may select mobile devices to communicate
using the alternative frequency spectrum by sending control messages to one or more
mobile devices, commanding the mobile devices to prompt their respective users for
agreement to communicate using the alternative frequency spectrum.
[0041] The mobile devices to which such control messages are sent may be identified in
any suitable way. In some embodiments, each mobile device seeking to associate with
base station 120B at a time when total load on the base station exceeds a threshold
indicating congestion exists or is likely to occur, may receive such a control message.
Accordingly, in the embodiment illustrated in FIG. 2, mobile device 144B may receive
such a control message when user 134B enters cell HOB and mobile device 144B attempts
to associate with base station 120B.
[0042] Though, in the embodiment illustrated in FIG. 2, range is used as a criterion for
identifying mobile devices to receive control messages commanding display of an offer to
a user. In the embodiment of FIG. 2, devices are identified based on proximity to base
station 120B. As a specific example, mobile devices within a region 230 immediately
surrounding base station 120 may receive a control message. In contrast, mobile devices
in region 232 may not receive such a control message.
[0043] The region 230 in which mobile devices receive the control message may be
determined in any suitable way. In the embodiment illustrated, the region 230 is
determined based on range to base station 120B. Here, any mobile device that has a range
less than Ri may receive a control message instructing the mobile device to present to its
user an offer to communicate using the alternative frequency spectrum. The range Ri may
be determined in any suitable way. In some embodiments, the range Ri may be a
predetermined amount, such as 50 meters, and may be the same for all cells. In other
embodiments, the range Ri may be selected in proportion to the size of the cell. In yet
other embodiments, the range Ri may be dynamically selected to yield a number of users
accepting an offer to communicate over the alternative frequency spectrum such that load
on the base station is reduced below a level associated with congestion. Regardless of
how range Ri is selected, in the embodiment illustrated in FIG. 2, only mobile device 142
is within range Ri of base station 120B. Accordingly, only mobile device 142B receives a
control message conveying an offer to accept communication in the alternative frequency
spectrum.
[0044] Though, it is not a requirement that a single approach be used by a base station for
identifying mobile devices to receive such a control message. For example, base station
120B may be programmed to initially attempt to solicit users of mobile devices within
region 230 to communicate using the alternative frequency spectrum. If the load on base
station 120B exceeds some threshold, even after soliciting users of devices within region
230 to use the alternative frequency spectrum, controller 120B may solicit devices outside
of region 230 to communicate using the alternative frequency spectrum. Moreover, it
should be recognized that any suitable combination of selection techniques may be
employed with any suitable order of precedence. For example, base station 120B may be
programmed to first select devices associated with a specific service plan within a
predetermined range of base station 120. If soliciting such devices does not result in a
sufficient number of mobile devices using the alternative frequency spectrum that the load
on base station 120B is reduced below a congestion threshold, base station 120B may
solicit devices with other service plans within a defined range or may select other devices,
outside the region, based on other criteria.
[0045] Regardless of the manner in which devices are identified, identified devices may
receive a control message that triggers the device to solicit user agreement to
communication using the alternative frequency spectrum. FIG. 3 is an example of a
mobile device 340 soliciting user agreement. In the example of FIG. 3, user agreement is
solicited based on a message presented through a graphical user interface 320 on display
310.
[0046] In this example, graphical user interface 320 may display a message in text format,
alerting the user of mobile device 340 to network congestion. This message may be
communicated as text, though icons or other graphical elements may be used to alert the
user of network congestion. FIG. 3 illustrates a simple message, presented in text, but it
should be recognized that any suitable message format with any suitable level of detail
may be used to communicate information concerning network congestion to the user.
[0047] In conjunction with the message alerting the user to network congestion, graphical
user interface 320 may include one or more mechanisms through which a user of device
340 may consent to communications using the alternative frequency spectrum. In this
example, the mechanism is text presenting an offer 322 to the user. In this example, the
text states "will you accept a lower bandwidth connection?" this text does not expressly
identify that the lower bandwidth connection is provided using the alternative frequency
spectrum, and express identification of the alternative frequency spectrum is not a
requirement of the invention. Though, in other embodiments, different or additional
information my be presented to the user which may describe the mechanism by which the
lower bandwidth connection is provided.
[0048] Additionally, offer 322 is not, in this example, expressly shown to include an
incentive. Though, offer 322 may include an express description of an incentive for the
user to consent to a lower bandwidth connection.
[0049] Regardless of the form and content of an offer, once an offer is made to a user
input reflecting consent or rejection of the offer may be obtained in any suitable way. In
the example of FIG. 3, in which the offer is presented through graphical user interface
320, user input may be obtained through one or more controls. As an example, graphical
user interface 320 is shown to contain controls 324 and 326. Controls 324 and 326 may be
implemented user technology as is known in the art for implementing a graphical user
interfaces. Selection of control 324 by a user may signify consent to communication using
the alternative frequency spectrum. Selection of control 326 by the user may signify
rejection of the offer to communicate over the alternative frequency spectrum.
[0050] One of skill in the art will recognize that FIG. 3 illustrates just one example of a
user interface through which an offer may be presented to a user an in response user input
may be obtained. Such an exchange may occur using other forms of graphical user
interfaces or other forms of interface entirely. For example, the exchange may be made
based on generated speech and the user input may be obtained through speech recognition.
[0051] Regardless of the manner in which the exchange of offer and user input occurs, if
the user consents to communication using the alternative frequency spectrum, mobile
device 340 may be configured to communicate using the alternative frequency spectrum.
In some embodiments, consenting to communication using the alternative frequency
spectrum may temporarily limit the functions performed by mobile device 340. For
example, mobile device 340 may temporarily not perform operations that require
communication of large amounts of data. As a specific example, when mobile device 340
is configured for communication in the alternative spectrum, it may not process user
request to download multi-media files or stream multi-media content. Though, in other
embodiments, when mobile device 340 is configured to communicate using the alternative
frequency spectrum, it may provide all functions, though performance of those functions
involving transfers of large amounts of data may be degraded by limited bandwidth
available using the alternative frequency spectrum.
[0052] Once a user has consenting to communicate using the alternative frequency
spectrum, this consent may remain in effect for a limited period of time after which mobile
device 340 may again communicate using the assigned frequency of cellular
communication system 100. That limited amount of time may be a predetermined fixed
amount of time or may be determined dynamically. That time could be determined
dynamically based on congestion within the cell containing mobile device 340, for
example. Accordingly, if aggregate bandwidth usage within the cell containing mobile
device 340 decreases or mobile device moves into a different cell, mobile device 340 may
revert to communicating using the assigned frequency spectrum. In other embodiments,
that limited time may be until mobile device 340 is turned off, resets, receives user input
indicating that the user would like a higher bandwidth connection or other triggering event
associated with user device 340.
[0053] In some embodiments, users may be offered an option to communicate using an
alternative frequency spectrum based on congestion in a region of communication system
100 that extends beyond a single cell. Such a region may have any suitable boundaries.
The boundaries, for example, may be based on distance from a cell or may be tied to
geopolitical boundaries. In such a scenario, if a user consents to communicating using the
alternative frequency spectrum, communications with that user's mobile device may occur
over the alternative frequency spectrum for as long as the user is within the larger region
and overall network usage in that larger region indicates congestion. As a specific
example, a larger region may be a city or metropolitan area such that a user who accepts
communication over the alternative frequency spectrum while at any location within that
larger region may continue to communicate over the alternative frequency spectrum even
as the user moves from cell to cell within that larger geographic region.
[0054] FIG. 3 illustrates a manner by which user consent to communicate over the
alternative frequency spectrum may follow the user as a the user moves from cell to cell.
FIG. 4 illustrates a mobile device 140 that a user moves from a cell 110A to cell HOB.
While in cell 110A, mobile device 140 may communicate with base station 120A. When
mobile device 140 moves to HOB, mobile device 140 may communicate through bay
station 120B. In passing from cell 110A to HOB, base station 120A may hand over
responsibility for communication with mobile device 140 to base station 120B.
[0055] Handover of mobile devices from a base station to an adjacent base station is
known in the art. Accordingly, base stations in a cellular communication system are
themselves networked such that information may be readily passed from one base station
to another. FIG. 4 illustrates handover information 410 passing over such a network from
base station 120A to base station 120B. Handover information 410 may represent
information as is known in the art.
[0056] Though, FIG. 4, illustrates that, in addition to handover information 410, base
station 120A provides spectrum type information 412 associated with the handover of
mobile device 140 to base station 120B. Spectrum type information 412 may signify to
base station 120B whether the user of mobile device 140 has selected the option of
communicating using the alternative frequency spectrum. In this way, if the user of
mobile device 140 has consented to communicate using the alternative frequency
spectrum, when base station 120B establishes communication with mobile device 140, it
will do so using the alternative frequency spectrum.
[0057] In addition, FIG. 4 illustrates that base stations may communicate other
information useful in implementing spectrum offload in accordance with some
embodiments of the invention. As shown in FIG. 4, base stations may exchange
bandwidth usage information 414. Such information may allow base stations to determine
aggregate network usage such that each base station may determine whether cellular
communications system 100 in the aggregate is operating above a congestion threshold.
Such information may be useful in embodiments in which users of mobile devices are
offered an option to communicate in an alternative frequency spectrum based on
congestion in the communication system or a larger region of the cellular communication
system, instead of or in addition to congestion in a single cell. Such information may also
be useful in embodiments in which mobile devices, once they begin communicating over
the alternative frequency spectrum continue to communicate over that alternative
frequency spectrum so long as the communication system, in at least a relevant region
operates in a congested state.
[0058] FIG. 4 provides a conceptual sketch of information that may be exchanged
between base stations. One of skill in the art will recognize that the information need not
be communicated directly between base stations. For example, though not shown in FIG.
4, handover information or other types of information may be conveyed from one base
station to another through one or more other network control devices. Though, the
mechanism by which information is communicated between base stations is not critical to
the invention and any suitable mechanism may be employed.
[0059] Turning now to FIG. 5, a flow chart of an exemplary process by which a base
station may operate according to some embodiments is illustrated. The process of FIG. 5,
begins when the base station receives an admission request from a mobile unit. Such an
admission request may be an admission request of the type known in the art for use in
cellular communication systems. The admission request may be associated with a mobile
device moving into the cell containing the base station. Though, in some embodiments, an
admission request may indicate that a mobile device has been powered on or for other
reason is seeking admission to enable use of the communication system.
[0060] Regardless of the reason that the device is seeking admission, the device may
generate a signal to the base station, which may be received at block 510.
[0061] In response to a received admission request, the base station may determine
whether a trigger condition for offering the user of the mobile device an option to
communicate over the alternative frequency spectrum exists. In the example illustrated in
FIG. 5, the trigger condition is based on both aggregate network usage and range between
the base station and the mobile device. Accordingly, in processing at block 512, the base
station may determine the range to the mobile device seeking admission.
[0062] Any suitable technique may be used to determine range. For example, many
communication systems include circuitry to make time of flight measurements that can be
converted into an estimate of range. In other scenarios, cellular communication systems
may use triangulation approaches to determine a location of a mobile device, which in turn
indicates a range to the device. Regardless of the manner in which the range is
determined, processing may proceed to block 514.
[0063] At block 514, the base station may determine a level of usage within the network.
The level of usage may be associated with any portion of the communication system. For
example, in some embodiments, usage may be determined solely within the cell occupied
by the base station performing the process of FIG. 5. In other embodiments, the usage
may be an aggregate usage over a region containing that cell. Regardless, the level of
usage may be determined in any suitable way. In embodiments in which the level of usage
is tied to the cell containing the base the station, the usage may be determined by
parameters of active communications with all of the mobile devices in that cell. In other
embodiments, a projected usage level may be determined at block 514. The projected
usage level may be based on an aggregate allocated bandwidth for the number of mobile
devices actively communicating with the base station. Though, any other suitable metric
may be used as an indication of a level of usage.
[0064] Regardless of how the usage is determined, the process may proceed to decision
block 520. At decision block 520, the process may branch, depending on whether a
trigger condition exists. In this trigger condition is based on the determined range at block
512 and the determined level of usage at block 514. If the determined level of usage
exceeds a threshold, such that the network or base station is deemed to be in a congested
state, and the device is within a range meeting a range criterion, the mobile device seeking
admission may be identified as a device to receive an offer for communication over the
alternative frequency spectrum.
[0065] Accordingly if a trigger condition exists such that the mobile device is to receive
an offer, the process may branch at decision block 520 to block 522. At block 522 the
base station may send one or more control message signifying an offer to communicate
using a lower bandwidth. If the offer is accepted by the user of the device, the process
may branch at decision block 530. The processing at decision block 530 may be based on
one or more control messages received from the mobile device. If those received control
messages indicate that the offer of lower bandwidth is accepted, the process may proceed
to block 532.
[0066] At block 532 the base station may establish communication with the mobile device
using the alternative frequency spectrum. In the embodiment illustrated in FIG. 5, the
alternative frequency spectrum is the digital television (DTV) spectrum. To avoid
interfering with DTV communications, the base station may establish communication
within white space of the DTV spectrum.
[0067] Once communication is established using the alternative frequency spectrum, the
process may proceed to block 534 where the base station records billing information. The
billing information recorded at block 534 may factor in an incentive offered to a user to
consent to communication using a lower bandwidth, alternative frequency spectrum. Such
an incentive, for example, may be reflected in a lower rate recorded for data
communications using the alternative frequency spectrum. However, any suitable
incentive may be offered and the processing at block 534 may reflect billing in accordance
with the incentives.
[0068] Conversely, if it is determined at decision block 520 that the mobile device seeking
admission does not satisfy the trigger conditions used to identify devices to receive an
offer of lower bandwidth communication, the process may branch from decision block 520
to block 540. At block 540, the base station may establish communication using the
assigned frequency spectrum for the base station. In the example of FIG. 5, the base
station is communicating using a 3G wireless standard and communication is established
at block 540 based on the frequency spectrum allocated for such 3G wireless
communications .
[0069] The process may proceed to block 542 where billing information is recorded . In
this example, the billing information recorded may be based on a service agreement of the
user of the mobile device without incentives. Accordingly, the billing information
recorded at block 542 may indicate a higher usage charge for data communications than
the billing information recorded at block 534.
[0070] Similarly, if it is determined at decision block 530 that the user of the mobile
device seeking admission does not consent to using the alternative frequency spectrum, the
process may branch from decision block 530 to block 540. At block 540, communication
may be established with the mobile device using the allocated frequency spectrum for the
base station. The process then may proceed to block 542 as described above.
[0071] FIG. 6 illustrates a corresponding process that may be performed on mobile device
seeking admission for communication through a base station. The process of FIG. 6 may
begin at block 610 where the mobile device may send an admission request to the base
station.
[0072] Processing on the mobile device may branch at decision block 620, depending on
whether the mobile device receives a control message indicating an offer to the user of the
mobile device to use lower bandwidth. If such a control message is received, the process
may branch to block 622. At block 622, the mobile device may display to its user the
offer for communication using lower bandwidth. The process may again branch at
decision block 630, depending on whether the user provides input indicating acceptance of
the lower bandwidth offer. If the user accepts the offer for lower bandwidth
communication, the process may proceed from decision block 630 to block 632. At block
632, the mobile device may establish communication using DTV white space.
[0073] Conversely, if it is determined at block 630 that the user has rejected the offer or
otherwise has not consented to communication at a lower bandwidth, the process may
branch from decision block 630 to block 640. At block 640, the mobile device may
establish communication using the allocated frequency spectrum of the base station. In
the example in which the mobile device is a 3G wireless device, processing at block 640
may entail establishing communication using the 3G wireless standard.
[0074] Conversely, if the mobile device does not meet criteria for receiving a bandwidth
for an offer of lower bandwidth communication or a congestion condition is not present,
the process may branch from decision block 620 to block 640. As described, when the
process reaches block 640, the mobile device may establish communication using the
assigned frequency spectrum of the base station, which is the 3G wireless spectrum in this
example.
[0075] Processing illustrated by the flow charts of FIGs. 5 and 6 may be performed in any
suitable way. The processing of FIG. 5, for example, may be implemented by
programming within a base station. Likewise, processing illustrated by the flowchart of
FIG. 6 may be performed using programming in a wireless device. Though, it should be
recognized that one or more of the steps of the processes in FIG. 5 and/or FIG. 6 may
implemented in hardware, firmware or some combination of hardware firmware, and
software or may be implemented in any suitable way.
[0076] A base station adapted for performing the process illustrated in FIG. 5 may be
constructed in any suitable way. Construction techniques as are known in the art for
constructing components of a communication system may be employed. Though, a base
station may be adapted to implement spectrum off load from an assigned spectrum to an
alternative frequency spectrum as illustrated in FIG. 7. FIG. 7 illustrates a base station
720. In the example of FIG. 7, base station 720 includes a 3G transceiver 724. 3G
transceiver 724 is coupled to antenna 722 through which 3G transceiver 724 may
communicate with multiple mobile devices using a frequency spectrum corresponding to
the frequency spectrum assigned to a cellular communication system. In this example, the
cellular communication system is a 3G wireless system and 3G transceiver 724 is adapted
to communicate using the frequency spectrum associated with 3G communications.
Accordingly, transceiver 724 may be a transceiver as is known in the art for a 3G wireless
communication system.
[0077] Additionally, base station 720 is illustrated as containing a DTV transceiver 726.
DTV transceiver 726 is configured for communication in an alternative frequency
spectrum, in this case, the DTV spectrum. DTV transceiver 726 may be constructed using
techniques as are known in the art. Though, rather than communicating DTV information,
DTV transceiver 726 communicates in portions of the DTV spectrum that are unused for
DTV signals. Accordingly, DTV transceiver 726 includes a mechanism to identify unused
portions of the DTV spectrum. In this example, DTV transceiver 726 is shown coupled to
whites space database 742. Whites space database 742 may contain information about
unused portions of the DTV spectrum in the vicinity of base station 720, and therefore
may be used to identify the frequency spectrum that may be used for lower bandwidth
communication.
[0078] Further, though DTV transceiver 726 may operate in the same spectrum that is
used to communicate DTV information, may not communication using the same format or
protocol that is used to communicate DTV signals. Rather, DTV transceiver 726 may be
configured, as one example, to communicate digital data in a standard conventionally used
for wireless communications between computing devices. As a specific example, DTV
transceiver 726 may be configured for communications using a WiFi or WiMAX standard.
Though it should be recognized that any protocol, whether standard or custom, may be
used.
[0079] Base station 720 may also contain a control portion 730. Control portion 730 may
be constructed using known construction techniques. Though, control portion 730 may be
constructed in any other suitable way. Control portion 730 may contain components that
perform processing as in a conventional base station. For example, admission control
component 734 may exchange control messages with a mobile device seeking admission
for communication through base station 720.
[0080] Admission control component 734 may access subscriber data 740 to determine
whether a mobile device seeking admission is authorized for communication. Admission
control components 734 may access subscriber data 740 to determine whether the mobile
device is associated with an authorized user. Accordingly, subscriber data 740 may
include subscriber data as is known in the art. Additionally, subscriber date 740 may
contain information indicating whether a user has consented to communicate using a lower
bandwidth during intervals when a congestion condition exists in a communication
system. Alternatively or additionally, subscriber data 740 may include information on a
subscribers' service plans which, alternatively or additionally may be used to identify
mobile devices to receive offers for communicating using lower bandwidth.
[0081] Band allocator component 736 may access this subscriber data to determine
whether a mobile device is to be provided an offer to communicate using a lower
bandwidth. Band allocator component 736 may also track congestion conditions to
determine when an offer to communicate at lower bandwidth is to be made. Band
allocator component 736 may also receive input from other sources that may be used to
identify mobile devices to receive such an offer. In the example of FIG. 7, control portion
730 is shown with a range detector component 732. Range detector component 732 may
measure a range between the base station and a mobile device seeking admission to the
network. This range information may be provided to band allocator component 736 for
use in identifying which mobile devices receive an offer for lower bandwidth
communication.
[0082] In the embodiment of FIG. 7, 3G transceiver 724, DTV transceiver 726 and control
portion 730 are shown coupled to a network 710. Network 710 may be one or more
different networks allowing base station 720 to exchange multiple types of information
with other components that form a communication system. For example, network 710
may provide a gateway to the Internet such that network messages from a mobile device
received either through 3G transceiver 724 or DTV transceiver 726 may be routed to
servers or other components accessible through the Internet. Likewise, information may
be routed from those component through either 3G transceiver 724 or DTV transceiver
726 to a mobile device. Alternatively or additionally, network 710 may allow control
portion 730 to interact with other base stations or components that control the
communication system. Such a network connection, for example, may facilitate sharing of
congestion information and handover information. Also, it should be appreciated that
FIG. 7 illustrates subscriber data 740 and white space data base 742 being local to base
station 720. Either or both of these sources of data may be resident on a component
accessible through network 710. Accordingly, it should be appreciated that FIG. 7 is an
illustration of a possible configuration for a base station, but other configuration are
possible.
[0083] Though not expressly illustrated in FIG. 7, a mobile device communicating with
base station 720 may have components corresponding to 3G transceiver 724, DTV
transceiver 726 and control portion 730. These components in a mobile device may be
constructed using techniques as are known in the art. Though, in combination, they
provide a mobile device an ability to communicate over an assigned frequency spectrum
for a cellular communication or communicate over an alternative frequency spectrum.
Additionally, such components may be adapted to control the mobile device to receive
commands indicating an offer is to be presented to a user of the device and receive and
convey user consent to or rejection of that offer.
[0084] Having thus described several aspects of at least one embodiment of this invention,
it is to be appreciated that various alterations, modifications, and improvements will
readily occur to those skilled in the art.
[0085] For example, it was described that congestion on a base station was determined
based on actual usage of mobile devices within a cell. In some embodiments, congestion
may be determined in other ways. As one example, congestion may be based on aggregate
bandwidth allocated or budgeted for devices operating within a cell. For example, each
mobile device associated with a base station may be allocated an amount of bandwidth. In
some embodiments, all mobile devices may be allocated the same amount of bandwidth.
Though, amounts of bandwidth may be allocated based on a subscription plan of a user of
a device, such that different devices have different allocations. As another example, each
device may be allocated an amount of bandwidth based on the characteristics of a device,
such at that each device receives an allocation equal to the full or a fractional amount of
the maximum bandwidth it could consume. Regardless of how bandwidth is allocated,
congestion could be detected if the sum of the allocated bandwidth for all mobile devices
exceeds the capacity of the base station.
[0086] As an example of another variation, congestion could be predicted rather than
measured. Prediction could be based on historical usage pattern. For example, a base
station could be deemed overloaded such that users are selected to receive an offer to
communicate using the alternative frequency spectrum at times of day that have
historically been congested, even if actual usage at that time is below the capacity of the
base station.
[0087] Also, trigger conditions for changing frequency spectrum used by the base station
were described in relation to cell or network congestion. Other suitable events may
constitute trigger conditions. For example, degradation in performance, low battery level,
and/or increase in RF power required for the mobile device to communicate effectively
with the base station.
[0088] These trigger conditions may be detected solely by components operating on the
base station. Though, it should be appreciated that the a mobile device may identify a
trigger condition and signal the trigger condition to the base station. For example, either
or both the base station and the mobile device may detect a bit error rate exceeding a
threshold as an indication of performance degradation.
[0089] Further, embodiments are described in which, upon detection of a trigger
condition, a base station switches from using a licensed spectrum to using an unlicensed
spectrum for communication with a portion of the mobile devices in its cell. The
alternative frequency spectrum need not be unlicensed. As an alternative, the alternative
frequency spectrum may be a lower quality licensed spectrum,
[0090] Such alterations, modifications, and improvements are intended to be part of this
disclosure, and are intended to be within the spirit and scope of the invention.
Accordingly, the foregoing description and drawings are by way of example only.
[0091] The above-described embodiments of the present invention can be implemented in
any of numerous ways. For example, the embodiments may be implemented using
hardware, software or a combination thereof. When implemented in software, the
software code can be executed on any suitable processor or collection of processors,
whether provided in a single computer or distributed among multiple computers.
[0092] Further, it should be appreciated that a computer may be embodied in any of a
number of forms, such as a rack-mounted computer, a desktop computer, a laptop
computer, or a tablet computer. Additionally, a computer may be embedded in a device
not generally regarded as a computer but with suitable processing capabilities, including a
Personal Digital Assistant (PDA), a smart phone or any other suitable portable or fixed
electronic device.
[0093] Also, a computer may have one or more input and output devices. These devices
can be used, among other things, to present a user interface. Examples of output devices
that can be used to provide a user interface include printers or display screens for visual
presentation of output and speakers or other sound generating devices for audible
presentation of output. Examples of input devices that can be used for a user interface
include keyboards, and pointing devices, such as mice, touch pads, and digitizing tablets.
As another example, a computer may receive input information through speech
recognition or in other audible format.
[0094] Such computers may be interconnected by one or more networks in any suitable
form, including as a local area network or a wide area network, such as an enterprise
network or the Internet. Such networks may be based on any suitable technology and may
operate according to any suitable protocol and may include wireless networks, wired
networks or fiber optic networks.
[0095] Also, the various methods or processes outlined herein may be coded as software
that is executable on one or more processors that employ any one of a variety of operating
systems or platforms. Additionally, such software may be written using any of a number
of suitable programming languages and/or programming or scripting tools, and also may
be compiled as executable machine language code or intermediate code that is executed on
a framework or virtual machine.
[0096] In this respect, the invention may be embodied as a computer readable medium (or
multiple computer readable media) (e.g., a computer memory, one or more floppy discs,
compact discs (CD), optical discs, digital video disks (DVD), magnetic tapes, flash
memories, circuit configurations in Field Programmable Gate Arrays or other
semiconductor devices, or other non-transitory, tangible computer storage medium)
encoded with one or more programs that, when executed on one or more computers or
other processors, perform methods that implement the various embodiments of the
invention discussed above. The computer readable medium or media can be transportable,
such that the program or programs stored thereon can be loaded onto one or more different
computers or other processors to implement various aspects of the present invention as
discussed above.
[0097] The terms "program" or "software" are used herein in a generic sense to refer to
any type of computer code or set of computer-executable instructions that can be
employed to program a computer or other processor to implement various aspects of the
present invention as discussed above. Additionally, it should be appreciated that
according to one aspect of this embodiment, one or more computer programs that when
executed perform methods of the present invention need not reside on a single computer or
processor, but may be distributed in a modular fashion amongst a number of different
computers or processors to implement various aspects of the present invention.
[0098] Computer-executable instructions may be in many forms, such as program
modules, executed by one or more computers or other devices. Generally, program
modules include routines, programs, objects, components, data structures, etc. that
perform particular tasks or implement particular abstract data types. Typically the
functionality of the program modules may be combined or distributed as desired in various
embodiments.
[0099] Also, data structures may be stored in computer-readable media in any suitable
form. For simplicity of illustration, data structures may be shown to have fields that are
related through location in the data structure. Such relationships may likewise be achieved
by assigning storage for the fields with locations in a computer-readable medium that
conveys relationship between the fields. However, any suitable mechanism may be used
to establish a relationship between information in fields of a data structure, including
through the use of pointers, tags or other mechanisms that establish relationship between
data elements.
[00100] Various aspects of the present invention may be used alone, in
combination, or in a variety of arrangements not specifically discussed in the embodiments
described in the foregoing and is therefore not limited in its application to the details and
arrangement of components set forth in the foregoing description or illustrated in the
drawings. For example, aspects described in one embodiment may be combined in any
manner with aspects described in other embodiments.
[00101] Also, the invention may be embodied as a method, of which an example
has been provided. The acts performed as part of the method may be ordered in any
suitable way. Accordingly, embodiments may be constructed in which acts are performed
in an order different than illustrated, which may include performing some acts
simultaneously, even though shown as sequential acts in illustrative embodiments.
[00102] Use of ordinal terms such as "first," "second," "third," etc., in the claims to
modify a claim element does not by itself connote any priority, precedence, or order of one
claim element over another or the temporal order in which acts of a method are performed,
but are used merely as labels to distinguish one claim element having a certain name from
another element having a same name (but for use of the ordinal term) to distinguish the
claim elements.
[00103] Also, the phraseology and terminology used herein is for the purpose of
description and should not be regarded as limiting. The use of "including," "comprising,"
or "having," "containing," "involving," and variations thereof herein, is meant to
encompass the items listed thereafter and equivalents thereof as well as additional items.
CLAIMS
What is claimed is:
1. A method of operating a communication service of the type that comprises
at least one base station adapted for exchanging communications with multiple mobile
devices within a region, the method comprising:
during a first interval, exchanging communications with each of a first plurality of
mobile devices within the region, the communications with the plurality of devices
collectively using a first amount of bandwidth within a licensed spectrum assigned to the
base station;
in a second interval during which the region contains a second plurality of mobile
devices, determining that a trigger condition exists based on the second plurality of mobile
devices; and
when it is determined that a trigger condition exists, exchanging communications
with a first portion of the second plurality of mobile devices using the licensed spectrum
and exchanging communications with a second portion of the second plurality of mobile
devices using an alternative frequency, the alternative frequency spectrum being different
than the first licensed spectrum.
2. The method of claim 1, wherein:
exchanging communications with a first portion of the second plurality of
mobile devices using the licensed spectrum comprises communicating in
accordance with a 3G standard; and
exchanging communications with a second portion of the second plurality
of mobile devices using the alternative frequency spectrum comprises exchanging
communications using a digital TV channel that is unassigned in the region.
3. The method of claim 1, further comprising:
selecting the second portion of the second plurality of mobile devices based at least
in part on position within the region.
4. The method of claim 3, wherein the selecting the second portion comprises
identifying mobile devices of the second plurality of mobile devices that are less than a
threshold distance from the base station.
5. The method of claim 4, further comprising:
determining the threshold distance based on one or more of time of day and
total bandwidth used by communications exchanged with the base station at the
second time.
6. A base station for a communication system providing a first service, the
base station comprising:
at least one transceiver adapted for exchanging communications with a
plurality of mobile devices using a first bandwidth in a first licensed spectrum and
using a second bandwidth in a second licensed spectrum, the first bandwidth in the
first licensed spectrum being allocated for use by the communication system in
providing the first service and the second bandwidth in a second licensed spectrum
allocated for use in providing a second service, different than the first service;
a control module, the control module adapted to:
determine cumulative bandwidth consumption in the first licensed
spectrum by mobile devices having a connection to the base station;
determine whether the cumulative bandwidth consumption is above
a threshold; and
when the cumulative bandwidth consumption is above the
threshold, configure the at least one transmitter for communication with a
first set of mobile devices using the first bandwidth and a second set of
mobile devices using the second bandwidth.
7. The base station of claim 6, wherein:
the control module further comprises a range detection component, the
range detection component being adapted to determine a range between the base
station and a mobile device in the vicinity of the base station;
the control module comprises a band allocation component, the band
allocation component assigning mobile devices of the plurality of devices to the
second set based on a range determined by the range detection component for each
device assigned to the second set being below a second threshold.
8. The base station of claim 6, wherein:
the control module comprises a band allocation component, the band allocation
component assigning mobile devices of the plurality of devices to the second set based on
a requested bandwidth received from each device assigned to the second set being below a
threshold.
9. The base station of claim 6, wherein:
the control module further comprises a range detection component, the
range detection component being adapted to determine a range between the base
station and a mobile device in the vicinity of the base station;
the control module comprises:
an admission control component, the admission control component
being adapted to exchange communications with mobile devices seeking a
connection to the base station, the communications comprising requests to
accept a lower bandwidth sent from the admission control component and a
responses from mobile devices indicating acceptance of the lower
bandwidth; and
a band allocation component, the band allocation component being
adapted to assign mobile devices of the plurality of devices to the second
set based on responses from the mobile devices indicating acceptance of the
lower bandwidth.
10. The base station of claim 6, wherein:
at least one transceiver is adapted for exchanging communications with mobile
devices assigned to the first group at a data rate in excess of 2 Mps and for exchanging
communications with mobile devices assigned to the second group at a data rate less than
1 Mps.