HYPER-CELLULAR COMMUNICATION SYSTEM
CLAIM OF PRIORITY
The present application claims priority from Chinese patent
5 application No. 201310106539.0 filed on March 29, 2013, the content of
which is hereby incorporated by reference into this application.
BACKGROUND
This invention relates to a hyper-cellular communication system.
10 Diversified services involved in smart phone and
machine-to-machine (M2M) applications have greatly affected the current
mobile cellular network. In particular, the proportion of the
medium-to-small traffic (background services of instant messages and
M2M services) in the current network is increasing gradually, and
15 signaling overheads produced thereby occupy even more than 60%
resources at the air interfaces. Here, the concept of the hyper-cell is
adopted to simplify signaling and to improve throughput. At present,
comprehensive studies have not been made on the mechanism of
optimizing the use of system resources by using a scheduling design of
20 diversified services in the mobile cellular network.
NTT Docomo has proposed the concept of phantom cell in 3rd
generatien partnership project. (3CPP) RAN. Thc rcscarchers have
considered the separation and optimization scenarios of control plane
and user plane, in which different cells had different signaling
25 configurations. However, the effect brought by diversified services and
the corresponding solutions have not been considered.
Further, 3GPP RAN work group has already started the study on
small cell enhancement, and the architecture of the hyper-cell has been
been considered. However, the types of diversified services have not
been considered. Therefore, this patent application is very necessary
also for the study on small cell enhancement.
Moreover, 3GPP has already set the definition for quality of service
5 (QoS) and the standard for Policy and Charging Control (PCC). However,
the load of the air interface produced by small data packets has not been
considered in the QCI table. In other words, the existing PCC
mechanism cannot resolve the problem of massive signaling overhead
produced by small data packets in the network.
10 Lastly, International Patent W020 1 1 / 14382412 has proposed a
scheduling mechanism for optimizing QoS within rhe orthogonal.
frequency division multiple access (OFDMA) system, and has mainly
researched the types of services of different applications and the
allocation of resource blocks at the air interface. However, the research
15 is limited to point-to-point link transmissions. Signaling overhead
produced by different types of services has not been considered.
SUMMARY
In the architecture of the heterogeneous cellular network, in
20 consideration of the coexistence of various types of services, especially
small traffics, the inventors of this invention have studied the selection of
base station and resource allocation for different users in this case. The
object of this invention is to provide a hyper-cellular communication system
and a hyper-cellular communication method for improving base station
25 association and resource allocation of differentiated services.
According to one embodiment of this invention, there is provided a
hyper-cellular communication system for associating a user to one of a
macro cell base station and a micro cell base station, the hyper-cellular
service classification index table including two parameters, namely user
mobility and signaling overhead; and a resource optimization function
unit for making decisions on base station association and wireless
resource allocation by referring to the quality of service classification
5 index table.
The hyper-cellular communication system according to one
embodiment of this invention can reduce frequent switches of the high
mobility user among micro cells and thereby balance the signaling traffics in
macro cells and micro cells.
10
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram illustrating the topology of the hyper-cell.
FIG. 2 is a diagram illustrating one method of measuring user
mobility.
15 FIG. 3 is a diagram illustrating the other method of measuring user
mobility.
FIG. 4 is a diagram illustrating the system architecture of the
hyper-cellular communication system.
FIG. 5 shows an example of a quality of service classification index
20 table QCI after adding two parameters, namely user mobility and signaling
overhead.
FIG. 6 is a structurc diagram schcmatica!ly illustrating a resource
optimization function unit ROF.
FIG. 7 is a structure diagram schematically illustrating a policy and
25 charging rules function unit PCRF.
FIG. 8 is a structure diagram schematically illustrating a module of a
gateway GW.
FIG. 9 is a flowchart used for the resource optimization function unit
FIG. 10 is a typical signaling interaction diagram of the hyper-cellular
communication system of this invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
One embodiment provides a hyper-cellular communication system
for associating a user to one of a macro cell base station and a micro cell
base station. The hyper-cellular communication system includes: a
gateway, including a user quality of service classification index table
including two parameters, namely user mobility and signaling overhead;
10 and a resource optimization function unit for making decisions on base
station association and wireless resource allocation by referring tc the
quality of service classification index table.
Further, in the hyper-cellular communication system according to
one embodiment, the resource optimization function unit may include:
15 an inquiry part for inquiring the user mobility in the quality of service
classification index table; and a decision-making part for selecting and
modulating a mode of associating the user and allocating data resources
and signaling resources based on a query result of the inquiry part.
Further, in the hyper-cellular communication system according to
20 one embodiment, the decision-making part may couple the user to a macro
cell when the query result of the inquiry part indicates that the user
rnobiiiey is higher than a first threshold value; and the decision-il-iaking
part may couple the user to a micro cell when the query result of the
inquiry part indicates that the user mobility is lower than the first
25 threshold value.
Further, in the hyper-cellular communication system according to
one embodiment, when the signaling overhead in the macro cell is higher
than a second threshold value, the inquiry part may inquire the signaling
table and determine whether the signaling overhead of the user's service
is higher than a third threshold value or not, and the decision-making
part may couple the user to the micro cell when it is determined that the
signaling overhead of the user's service is higher than the third threshold
5 value.
Further, the hyper-cellular communication system according to
one embodiment may further include a policy and charging rules function
unit, and the policy and charging rules function unit may include: a
measuring part for measuring the user mobility and the signaling
10 overhead of the user's service; and a requesting part for requesting the
gateway to update the quality s f service classification index table based
on a measurement result of the measuring part.
Further, in the hyper-cellular communication system according to
one embodiment, the measuring part may measure a switching frequency
15 of the user among micro cells per unit time; and the measuring part may
determine that the user is a high mobility user when a result of the
switching frequency is higher than a fourth threshold value, and determine
that the user is a low mobility user when the result of the switching
frequency is lower than the fourth threshold value.
20 Further, in the hyper-cellular communication system according to
one embodiments, the measuring part may measure a frequency of
changes in signal strength per unit time; and the measuring part iimy
determine that the user is a high mobility user when the frequency of
changes in signal strength per unit time is higher than a fifth threshold
25 value, and determine that the user is a low mobility user when the
frequency of changes in signal strength per unit time is lower than the fifth
threshold value.
According to one embodiment, there is provided a hyper-cellular
station and a micro cell base station, including: inquiring user mobility in a
quality of service classification index table including two parameters,
namely user mobility and signaling overhead; and selecting and
modulating a mode of associating the user and allocating data resources
5 and signaling resources based on a query result of the inquiring.
Further, the hyper-cellular cornmunication method according to
one embodiment may further include: coupling the user to a macro cell
when the query result indicates that the user mobility is higher than a
first threshold value; and coupling the user to a micro cell when the query
10 result indicates that the user mobility is lower than the first threshold
value.
Further, the hyper-cellular communication method according to
one embodiment may further include: inquiring the signaling overhead of
the user's service in the quality of service classification index table when
15 the signaling overhead in the macro cell is higher than a second threshold
value; and determining whether the signaling overhead of the user's
service is higher than a third threshold value or not, and then coupling
the user to a micro cell when it is determined that the signaling overhead
of the user's service is higher than the third threshold value.
Further, the hyper-cellular communication method according to
one embodiment may further include: measuring the user mobility and
the signaling overhead of the uscr's scrvicc; and requesting the gateway
to update the quality of service classification index table based on a
result of the measuring.
25 Further, in the hyper-cellular communication method according to
one embodiment, the measuring may include: measuring a switching
frequency of the user among micro cells per unit time; and determining that
the user is a high mobility user when a result of the switching frequency is
mobility user when the result of the switching frequency is lower than the
fourth threshold value.
Further, in the hyper-cellular communication method according to
one embodiment, the measuring may include: measuring a frequency of
5 changes in signal strength per unit time; and determining that the user is a
high mobility user when the frequency of changes in signal strength per
unit time is higher than a fifth threshold value, and determining that the
user is a low mobility user when the frequency of changes in signal
strength per unit time is lower than the fifth threshold value.
10 The hyper-cellular communication system according to one
embodiment can reduce frequent switches of the high mobility user among
micro cells and thereby balance the signaling traffics in macro cells and
micro cells. Moreover, the hyper-cellular communication system
according to one embodiment optimizes the resources in the mobile
15 cellular network for "actual" various user data services, and the
operating time (including battery consumption) of the user terminal is
not influenced. The novel architecture proposed in this invention is in
good compatibility with the current network system, in other words, the
novel architecture proposed can be supported without bulk update of
20 network equipment.
Hereinafter, the present inventions are described in detail with
reference :c the drawings. FIG. 1 is a diagram illustrating the topology- of
the hyper-cell. The macro cells and the micro cells form an overlapping
coverage area within the hyper-cellular communication system. The
25 coverage area of the macro cells is much larger than that of the micro
cells. However, the resource consumption of the macro cells is also
obviously higher than that of the micro cells.
The wireless resources within both the macro cells and the micro
because the total bandwidth is limited, the allocation ratio needs to be
optimized. In this case, considerations need to be made for service delay,
service optimum rate, channel status and interference level in the
well-known art, as well as signaling overhead of service and mobility of users
5 requesting for service.
In evaluating the selection of access threshold based on user mobility,
it is necessary to select the suitable parameters through the optimization of
the system.
Similarly, in evaluating signaling overhead of the macro cell, it is
10 necessary to optimize the design of the specific load transfer threshold
depending on the actual system parameters.
It is easy to estimate the signaling overhead of a service, but some
special measuring methods need to be considered for mobility of a user.
FIG. 2 and FIG. 3 illustrate separate two methods of measuring the mobility
15 of one user.
FIG. 2 is a diagram illustrating one method of measuring user
mobility. The ID of a user to be associated with each micro cell, which
varies with time, is recorded. The switching frequency of the user among
micro cells per unit time is calculated. The user is determined as a high
20 mobility user when the result of the switching frequency is higher than a
given threshold value, and the user is determined as a low mobility user
when the result of the sya7itching frequency is lower than the given threshold
value. Measurement of the mobility is carried out by a measuring part 21
of a policy and charging rules function unit PCRF as described later, and the
25 detailed contents are described later.
FIG. 3 is a diagram illustrating the other method of measuring user
mobility. The changes in the strength of the signal received from the
macro cell base stations by the user are recorded. A higher frequency of
higher user mobility. The user is determined as a high mobility user when
the frequency of changes in signal strength per unit time is higher than a
given threshold value, and the user is determined as a low mobility user
when the frequency of changes in signal strength per unit time is lower
5 than the given threshold value. Measurement of the mobility is carried out
by the measuring part 21 of the policy and charging rules function unit
PCRF as described later, and the detailed contents are described later.
FIG. 4 is a diagram illustrating the system architecture of the
hyper-cellular communication system. The hyper-cellular communication
10 system includes a resource optimization function unit ROF, a policy and
charging rules function unit PCRF, an access network discovery and
selection function unit ANDSF, a mobility management entity unit MME,
a gateway GW, a user entity unit UE, a macro cell base station, and a
micro cell base station. The gateway GW is provided with a quality of
15 service (QoS) classification index table QCI. These units may be
configured by processors operable according to programs and/or dedicated
hardware circuits.
FIG. 5 shows an example of the quality of service classification index
table QCI after adding two parameters, namely user mobility and signaling
20 overhead.
FIG. 5 exemplifies four types of users, respectively being high
rnobilitjr and high throughput rate (IIMIIT), low- mobility and high
throughput rate (LMHT), high mobility and low throughput rate (HMLT),
low mobility and low throughput rate (LMLT). Here, high throughput
25 rate represents low signaling overhead, and low throughput rate
represents high signaling overhead. The user with high mobility and
high throughput rate (HMHT), for example, is UE1, UE2, for which the
signaling overhead is 15% as an example and the mobility is high. The
UE3, for which the signaling overhead is 6% as an example and the
mobility is low. The user with high mobility and low throughput rate
(HMLT), for example, is UE5, UE6, for which the signaling overhead is
60Yo as an example and the mobility is high. The user with low mobility
5 and low throughput rate (LMLT), for example, is UE4, UE7 to UEn, for
which the signaling overhead is 40% as an example and the mobility is
low.
FIG. 6 is a structure diagram schematically illustrating the resource
optimization function unit ROF. The resource optimization function unit
10 mainly has the function of making decisions on base station association
and wireless resource allocation, and also has the functions of inquiring
system status and sending result of decisions. The resource optimization
function unit ROF includes an inquiry part 11, a decision-making part 12,
and a sending part 13. The inquiry part 11 is used for inquiring the QCI
15 information of the user, current system traffic, channel status, and
interference level. The decision-making part 12 is used for selecting and
modulating the mode of associating the user and for allocating data
resources and signaling resources. The sending part 13 is used for
sending the result of decisions to the policy and charging rules function
20 unit PCRF. These parts may be configured by processors operable
according to programs and/or dedicated hardware circuits.
FIG. 7 is a structure diagram schcmaticalljr illustrating the policy and
charging rules function unit PCRF. Besides the functions in the
well-known art, the policy and charging rules function unit PCRF is further
25 in charge of measuring user mobility and signaling overhead of service.
Further, as the core of the network, the policy and charging rules funetion
unit PCRF is the functional entity for producing and transmitting a large
number of signals and data.
measuring part 2 1, a receiving part 22, a sending part 23 and a requesting
part 24. These parts may be configured by processors operable according
to programs and/or dedicated hardware circuits.
The measuring part 21 is used for measuring user mobility and
5 signaling overhead of service. The measuring part 21 has two
measuring methods illustrated in FIG. 2 and FIG. 3.
According to the measuring method as illustrated in FIG. 2, the
measuring part 2 1 records the ID of a user to be associated with each micro
cell, which varies with time, and calculates the switching frequency of the
10 user among micro cells per unit time. The measuring part 21 determines
that the user is a high mobility user when the result of rhe switching
frequency is higher than a given threshold value, and determines that the
user is a low mobility user when the result of the switching frequency is
lower than the given threshold value.
15 According to the measuring method as illustrated in FIG. 3, the
measuring part 2 1 records changes in the strength of the signals received
from the macro cell base stations by the user. A higher frequency of
changes in signal strength per unit time with a larger change indicates
higher user mobility. The user is determined as a high mobility user when
20 the frequency of changes in signal strength per unit time is higher than a
given threshold value, and the user is determined as a low mobility user
.tvher, the frequency of changes in signal strength per unit time is loweithan
the given threshold value.
The receiving part 22 is used for receiving the result of the decision
25 sent by the sending part of the resource optimization function unit ROF.
The sending part 23 is used for scnding the result of down-link
decision to the mobile management entity unit MME, sending the result
of up-link decision to the access network discovery and selection
user entity unit UE.
The requesting part 24 requests the gateway GW to update the
user quality of service classification index table QCI based on the
measuring result of the measuring part 2 1.
5 FIG. 8 is a structure diagram schematically illustrating the gateway
GW. The gateway GW includes a reporting part 31, an updating part 32,
and a user quality of service classification index table QCI. These parts
may be configured by processors operable according to programs and/or
dedicated hardware circuits. The reporting part 31 is used for reporting
10 the user quality of service classification index table QCI to the resource
optimization function unit ROF.
The updating part 32 is used for updating the user quality of
service classification index table QCI.
Two parameters are added to the user quality of service
15 classification index table QCI, namely user mobility and signaling
overhead of service.
FIG. 9 is a flowchart used for the resource optimization function unit
ROF to provide the selection service of associating the base stations.
In Step S1, the user requests the policy and charging rules function
20 unit PCKF for base station association. In Step S2, the inquiry part of
the resource optimization function unit ROF inquires the user mobility in
the user quality of service classification index tablc QCI and deteri~~ines
whether the user mobility is high or not. When it is determined that the
user mobility is high, the flow proceeds to Step S3, in which the
25 decision-making part of the resource optimization function unit ROF
couples the user to a macro cell. On the other hand, when it is
determined in Step S2 that the user mobility is low, the flow proceeds to
Step S4, in which the decision-making part of the resource optimization
switches of a high mobility user among micro cells can be reduced.
Further, after proceeding to Step S3 of coupling the user to a macro
cell, the flow proceeds to Step S5, in which it is determined whether the
signaling overhead in the macro cell is too large or not, in other words,
5 exceeds a given threshold value or not. When it is determined that the
signaling overhead in the macro cell is too large, in other words, exceeds a
given threshold value, the flow proceeds to Step S6, in which the inquiry
part of the resource optimization function unit ROF inquires the
signaling overhead of the user's service in the user quality of service
10 classification index table QCI, and determines whether the signaling
overhead of the user's service is too large or not, in other words, exceeds
a given threshold value or not. When it is determined that the signaling
overhead of the user's service is too large, in other words, exceeds a given
threshold value, the flow proceeds to Step S4, in which the
15 decision-making part of the resource optimization function unit ROF
couples the user to a micro cell.
In this way, the signaling traffics in macro cells and micro cells can
be balanced.
On the other hand, when it is determined in Step S5 that the
20 signaiing overhead in the macro cell is not too large, in other words, lower
than a given threshold value, the flow returns to Step S3 and repeats the
determination of Step S5. When it is determined in Step S6 that the
signaling overhead of the user's service is not too large, in other words,
lower than a given threshold value, the flow returns to Step S3 and repeats
25 the determination of Step S6.
FIG. 10 is a typical signaling interaction diagram of the hyper-cellular
communication system. Here, the ROF carries out the user association and
the resource allocation, and the other modules are in charge of reporting the
The user entity unit UE requests the policy and charging rules
function unit PCRF for base station association. The policy and
charging rules function unit PCRF requests the gateway GW to update
the user quality of service classification index table QCI. The policy and
5 charging rules function unit PCRF requests the resource optimization
function unit ROF for selection of associating the user. The gateway GW
reports the user quality of service classification index table QCI to the
resource optimization function unit ROF. The resource optimization
function unit ROF selects the mode of associating the user. The policy
10 and charging rules function unit PCRF informs the gateway GW and the
mobile management entity unit MME of the result of down-link decision
and sends the result of up-link decision to the access network discovery
and selection function unit ANDSF. The access network discovery and
selection function unit ANDSF informs the user entity unit UE of the
15 mode of up-link association.
When the user quality of service classification index table QCI
changes, for example, when the user mobility changes, the resource
optimization function unit ROF makes decisions on the mode of the
resource association and the band width distribution, and informs the
20 policy and charging rules function unit PCRF of the result of decisions.
The policy and charging rules function unit PCRF requests the gateway
GW to update the user quality of scrvicc classification index table QCI.
The policy and charging rules function unit PCRF informs the mobile
management entity unit MME of the result of down-link decision, and
25 informs the access network discovery and selection function unit ANDSF
of the result of up-link decision. The access network discovery and
selection function unit ANDSF informs the user entity unit UE of the
result of up-link decision.
includes various modifications. The above-described embodiments are
explained in details for better understanding and are not limited to those
including all the configurations described above. A part of the configuration
of one embodiment may be replaced with that of another embodiment; the
5 configuration of one embodiment may be incorporated to the configuration of
another embodiment. A part of the configuration of each embodiment may
be added, deleted, or replaced by that of a different configuration.
The above-described configurations, functions, and processors, for all
or a part of them, may be implemented by hardware: for example, by
10 designing an integrated circuit. The above-described configurations and
functions may be implemented by software, which means that a processor
interprets and executes programs providing the functions. The information
of programs, tables, and files to implement the functions may be stored in a
storage device such as a memory, a hard disk drive, or an SSD (Solid State
15 Drive), or a storage medium such as an IC card, or an SD card.

WHAT IS CLAIMED IS:
1. A hyper-cellular communication system for associating a user to
one of a macro cell base station and a micro cell base station, the
hyper-cellular communication system comprising:
a gateway comprising a user quality of service classification index
table including two parameters, namely user mobility and signaling
overhead; and
a resource optimization function unit for making decisions on
base station association and wireless resource allocation by referring to
10 the quality of service classification index table.
2. The hyper-cellular communication system according to claim 1,
wherein the resource optimization function unit comprises:
an inquiry part for inquiring the user mobility in the quality of
15 service classification index table; and
a decision-making part for selecting and modulating a mode of
associating the user and allocating data resources and signaling
resources based on a query result of the inquiry part.
3. The hyper-cellular communication system according to claim 2,
wherein:
-ehe decision-making part couples the user to a macro cell when the
query result of the inquiry part indicates that the user mobility is higher
than a first threshold value; and
25 the decision-making part couples the user to a micro cell when the
query result of the inquiry part indicates that the user mobility is lower
than the first threshold value.
wherein:
when the signaling overhead in the macro cell is higher than a
second threshold value, the inquiry part inquires the signaling overhead
of the user's service in the quality of service classification index table and
5 determines whether the signaling overhead of the user's service is higher
than a third threshold value or not; and
the decision-making part couples the user to the micro cell when it
is determined that the signaling overhead of the user's service is higher
than the third threshold value.
5. The hyper-cellular commu~ications ystem according to claim I,
further comprising a policy and charging rules function unit,
wherein the policy and charging rules function unit comprises:
a measuring part for measuring the user mobility and the
15 signaling overhead of the user's service; and
a requesting part for requesting the gateway to update the
quality of service classification index table based on a measurement
result of the measuring part.
6. The hyper-cellular communication system according to claim 5,
wherein:
the measuring part measures a switching fi-equency of the user
among micro cells per unit time; and
the measuring part determines that the user is a high mobility user
25 when a result of the switching frequency is higher than a fourth threshold
value, and determines that the user is a low mobility user when the result of
the switching frequency is lower than the fourth threshold value.
wherein:
the measuring part measures a frequency of changes in signal
strength per unit time; and
the measuring part determines that the user is a high mobility user
when the frequency of changes in signal strength per unit time is higher
than a fifth threshold value, and determines that the user is a low mobility
user when the frequency of changes in signal strength per unit time is
lower than the fifth threshold value.
10 8. A hyper-cellular communication method for associating a user
to one of a macro cell base station and a micro cell base station, comprising:
inquiring user mobility in a quality of service classification index
table including two parameters, namely user mobility and signaling
overhead; and
15 selecting and modulating a mode of associating the user and
allocating data resources and signaling resources based on a query
result of the inquiring.
9. The hyper-cellular communication method according to claim 8,
20 further comprising:
coupling the user to a macro cell when the query result indicates
that the user mobility is highcr than a first threshold value; and
coupling the user to a micro cell when the query result indicates
that the user mobility is lower than the first threshold value.
10. The hyper-cellular communication method according to claim 9,
further comprising:
inquiring the signaling overhead of the user's service in the quality
macro cell is higher than a second threshold value; and
determining whether the signaling overhead of the user's service
is higher than a third threshold value or not, and then coupling the user
to a micro cell when it is determined that the signaling overhead of the
5 user's service is higher than the third threshold value.
11. The hyper-cellular communication method according to claim 8,
further comprising:
measuring the user mobility and the signaling overhead of the
10 user's service; and
requesting the gateway to update the quality of service
classification index table based on a result of the measuring.
12. The hyper-cellular communication method according to claim
15 1 1, wherein the measuring comprises:
measuring a switching frequency of the user among micro cells per
unit time; and
determining that the user is a high mobility user when a result of the
switching frequency is higher than a fourth threshold value, and
20 determining that the user is a low mobility user when the result of the
switching frequency is lower than the fourth threshold value.
13. The hyper-cellular communication method according to claim
1 1, wherein the measuring comprises:
25 measuring a frequency of changes in signal strength per unit time;
and
determining that the user is a high mobility user when the frequency
of changes in signal strength per unit time is higher than a fifth threshold
frequency of changes in signal strength per unit time is lower than the fifth
threshold value.
14. A hyper-cellular communication system, substantially as
5 herein described with reference to accompanying drawings and
examples.
15. A hyper-cellular communication method, substantially as
herein described with reference to accompanying drawings and
10 examples.