U.S. patent application number 16/361244 was filed with the patent office on 2019-07-18 for wireless communication device for controlling a target transmission power of a target cell using a classification of an overall .
This patent application is currently assigned to SONY CORPORATION. The applicant listed for this patent is SONY CORPORATION. Invention is credited to Qimei CUI, Zhilin LI, Yang LIU, Hui TIAN, Meng WANG.
Application Number | 20190223112 16/361244 |
Document ID | / |
Family ID | 54169398 |
Filed Date | 2019-07-18 |
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United States Patent
Application |
20190223112 |
Kind Code |
A1 |
TIAN; Hui ; et al. |
July 18, 2019 |
WIRELESS COMMUNICATION DEVICE FOR CONTROLLING A TARGET TRANSMISSION
POWER OF A TARGET CELL USING A CLASSIFICATION OF AN OVERALL CHANNEL
QUALITY IN A CELL CLUSTER
Abstract
A wireless communication device, a wireless communication method
and a wireless communication system. The wireless communication
device includes: a classification unit, used for, based on the
channel qualities of downlinks of a target cell and other cells in
a cell cluster on a specific resource block, classifying the
overall condition of the channel quality; and a control unit, used
for controlling, so as to determine the target transmitting power
of the target cell on the specific resource block by using a power
distribution method adapting to the classification. According to
the scheme, the system throughput of a wireless network on the
specific resource block under dense cell distribution can be
maximized.
Inventors: |
TIAN; Hui; (Beijing, CN)
; CUI; Qimei; (Beijing, CN) ; WANG; Meng;
(Beijing, CN) ; LI; Zhilin; (Beijing, CN) ;
LIU; Yang; (Beijing, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SONY CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
SONY CORPORATION
Tokyo
JP
|
Family ID: |
54169398 |
Appl. No.: |
16/361244 |
Filed: |
March 22, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15122557 |
Aug 30, 2016 |
10313985 |
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PCT/CN2015/073702 |
Mar 5, 2015 |
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16361244 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 52/265 20130101;
H04W 72/044 20130101; H04W 52/241 20130101; H04W 52/24 20130101;
H04W 52/244 20130101 |
International
Class: |
H04W 52/26 20060101
H04W052/26; H04W 72/04 20060101 H04W072/04; H04W 52/24 20060101
H04W052/24 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 28, 2014 |
CN |
201410123043.9 |
Claims
1. A wireless communication device, comprising: circuitry
configured to classify an overall channel quality based on the
channel qualities of downlinks, on a specific resource block, of a
target cell and other cells in a cell cluster; and control a target
transmission power, on the specific resource block, of the target
cell using the classification of the overall channel quality so
that the target cell operates with the target transmission
power.
2. The wireless communication device of claim 1, wherein according
to a predetermined classification criterion, the classification of
the overall channel quality comprises at least one of a first
classification (good), a second classification (normal), and a
third classification (bad).
3. The wireless communication device of claim 2, wherein each of
the channel qualities is characterized by a signal to interference
plus noise ratio (SINR).
4. The wireless communication device of claim 3, wherein the
predetermined classification criterion comprises: the overall
channel quality is classified as the first classification (good) if
SINRs of the target cell and the other cells are greater than a
threshold value by a first predetermined amount; the overall
channel quality is classified as the third classification if SINRs
of the target cell and the other cells are less than a threshold
value by a predetermined amount; and the overall channel quality is
classified as the second classification in other cases.
5. The wireless communication device of claim 1, wherein the
circuitry is configured to calculate an inter-cell SINR of the
target cell with respect to a first other cell on the specific
resource block.
6. The wireless communication device of claim 5, wherein the
inter-cell SINR is defined as: a ratio of the interference on the
first other cell from the target cell versus a sum of all
interference and noise the first other cell is subjected to, on the
specific resource block.
7. The wireless communication device of claim 6, wherein the
circuitry is configured to calculate a sum of inter-cell SINRs of
the target cell with respect to all of other cells in the cell
cluster on the specific resource block.
8. The wireless communication device of claim 7, wherein the
circuitry is configured to control so as to: determine the target
transmission power by decreasing, by a certain step length,
transmission power of the target cell on the specific resource
block if it is determined that the sum of the inter-cell SINRs is
greater than 1.
9. A wireless communication method, comprising: classifying, using
circuitry, an overall channel quality based on the channel
qualities of downlinks, on a specific resource block, of a target
cell and other cells in a cell cluster; and controlling a target
transmission power, on the specific resource block, of the target
cell using the classification of the overall channel quality so
that the target cell operates with the target transmission
power.
10. A wireless communication device, comprising: circuitry
configured to classify a user equipment in a cell cluster based on
average channel quality of downlinks to the user equipment in a
predetermined time period; allocate a resource block set to the
user equipment at least partly based on a classification of the
user equipment, wherein the resource block set is allocated to user
equipments of the same classification; and control a target
transmission power of a target cell on a specific resource block
using the classification of the user equipment scheduled by the
target cell on the specific resource block so that the target cell
operates with the target transmission power.
11. The wireless communication device of claim 10, wherein the
average channel quality is characterized by an average SINR of the
user equipment in the predetermined time period.
12. The wireless communication device of claim 11, wherein the
circuitry is further configured to: classify the user equipment
into a first type if the average SINR is greater than a threshold
value by a first predetermined amount; classify the user equipment
into a second type if the average SINR is less than the threshold
value by a second predetermined amount; and classify the user
equipment into a third type if it is not classified as the first
type or the second type.
13. The wireless communication device of claim 10, wherein the
circuitry is configured to allocate the resource block set to the
user equipment at least partly based on the numbers of user
equipments of different types.
14. The wireless communication device of claim 13, wherein the
circuitry is configured to allocate the resource block set at least
partly based on service requirements of the user equipments of
different types.
15. The wireless communication device of claim 13, wherein the
circuitry is configured to calculate an inter-cell SINR of the
target cell with respect to a first non-target cell on the specific
resource block, wherein the inter-cell SINR is defined as: a ratio
of the interference on the first non-target cell from the target
cell versus a sum of all interference and noise the first
non-target cell is subjected to, on the specific resource
block.
16. The wireless communication device of claim 15, wherein the
circuitry is configured to calculate a sum of inter-cell SINRs of
the target cell with respect to all of non-target cells in the cell
cluster on the specific resource block.
17. The wireless communication device of claim 16, wherein the
circuitry is configured to: determine whether the sum of the
inter-cell SINRs is less than 1 if the user equipment is of the
first type; and determine the target transmission power of the
target cell on the specific resource block, by making a first-order
partial derivative of a total throughput of all cells in the cell
cluster on the specific resource block with respect to transmission
power of the target cell on the specific resource block equal to 0,
if it is determined that the sum of the inter-cell SINRs is less
than 1.
18. The wireless communication device of claim 16, wherein the
circuitry is configured to: determine whether the sum of the
inter-cell SINRs is less than 1 if the user equipment is of the
first type; and determine the target transmission power by
decreasing, by a certain step length, transmission power of the
target cell on the specific resource block, if it is determined
that the sum of the inter-cell SINRs is not less than 1.
19. The wireless communication device of claim 12, wherein the
circuitry is configured to determine the target transmission power
of the target cell on the specific resource block by making a
first-order partial derivative of a total throughput of all cells
in the cell cluster on the specific resource block with respect to
transmission power of the target cell on the specific resource
block equal to 0, if the user equipment is of the second type.
20. The wireless communication device of claim 12, wherein the
circuitry is configured to: respectively compare values of
first-order and second-order partial derivatives of a total
throughput of all cells in the cell cluster on the specific
resource block with respect to transmission power of the target
cell on the specific resource block with 0; and determine the
target transmission power of the target cell on the specific
resource block by making the first-order partial derivative equal
to 0, in a case that the user equipment is of the third type and it
is determined by the calculation unit via the comparison that the
value of the first-order partial derivative is greater than 0 and
the value of the second-order partial derivative is less than 0.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 15/122,557, filed Aug. 30, 2016, which is based on PCT filing
PCT/CN2015/073702, filed Mar. 5, 2015, and claims priority to CN
201410123043.9, filed Mar. 28, 2014, the entire contents of each
are incorporated herein by reference.
FIELD
[0002] The disclosure generally relates to the technical field of
wireless communication, and in particular to a wireless
communication device, a wireless communication method and a
wireless communication system, which can perform an efficient power
control between cells.
BACKGROUND
[0003] In order to further solve the problem of data service
requirement of a wireless cellular network, 3GPP (The 3rd
Generation Partnership Project) proposed, in the latest LTE-A
evolution version Release 12, a solution for denser small cell
deployment. By deploying small cells, a system throughput can be
improved, a more effective coverage can also be provided, so as to
realize a load balancing. In a whole LTE-A network, the small cells
are mainly deployed in the following three scenarios: deployed with
a frequency same as a macro base station, deployed with a frequency
different from a macro base station, or deployed without a macro
base station. In a scenario of being deployed in the frequency
different from the macro base station, the small cell operates with
a frequency different from the macro base station, and thus
cross-layer interference between the macro base station and the
small cell may be ignored, which is consistent with the research
method for the scenario of deployment without a macro base station.
Therefore, from a perspective of network interference analysis, the
small cell deployment may be classified into two types: a
same-frequency deployment with only cross-layer interference
between the small cell and the macro base station, and a
different-frequency deployment with only same-layer interference.
And the different-frequency deployment of the small cell is a
hotspot in 3GPP research.
[0004] Although a dense small cell deployment can greatly improve
the spectrum efficiency of a network, it may bring serious
same-layer interference, and increase the operation cost. In
another aspect, interference of a small cell network, especially
interference in a dense deployment, is a bottleneck of a further
improvement of system performance. Therefore, interference
management and energy efficiency are currently research focuses of
a small cell project group of 3GPP. In a case of the
different-frequency deployment, that is, in a case that the
cross-layer interference between the macro base station and the
small cell is not taken into account, the dense deployment of small
cells may make a user equipment be interfered by many other small
cells at the same time. Therefore, the same-layer interference is a
main constraint on system performance improvement.
SUMMARY
[0005] A wireless communication device is provided according to an
aspect of the present disclosure. The wireless communication device
includes: a classification unit, configured to classify, based on
channel qualities of downlinks of a target cell and other cells in
a cell cluster on a specific resource block, an overall channel
quality; and a control unit, configured to perform a control to
determine a target transmission power of the target cell on the
specific resource block by a power allocating method adaptive to a
classification of the overall channel quality.
[0006] A wireless communication method is provided according to
another aspect of the present disclosure. The wireless
communication method includes: classifying, based on channel
qualities of downlinks of a target cell and other cells in a cell
cluster on a specific resource block, an overall channel quality;
and performing a control to determine a target transmission power
of the target cell on the specific resource block by a power
allocating method adaptive to a classification of the overall
channel quality.
[0007] A wireless communication device is provided according to
another aspect of the present disclosure. The wireless
communication device includes: a classification unit, configured to
classify a user equipment in a cell cluster based on average
channel quality of downlinks to the user equipment in a
predetermined time period; an allocating unit, configured to
allocate a resource block set to the user equipment at least partly
based on a classification of the user equipment, wherein the
allocating unit allocates a same resource block set to user
equipments of the same classification; and a control unit,
configured to perform a control to determine a target transmission
power of a target cell on a specific resource block by a power
allocating method adaptive to a classification of the user
equipment scheduled by the target cell on the specific resource
block.
[0008] A wireless communication method is provided according to
another aspect of the present disclosure. The wireless
communication method includes: classifying a user equipment in a
cell cluster based on average channel quality of downlinks to the
user equipment in a predetermined time period; allocating a
resource block set to the user equipment at least partly based on a
classification of the user equipment, wherein the allocating unit
allocates a same resource block set to user equipments of the same
classification; and performing a control to determine a target
transmission power of a target cell on a specific resource block by
a power allocating method adaptive to a classification of the user
equipment scheduled by the target cell on the specific resource
block.
[0009] A wireless communication system is further provided
according to anther aspect of the present disclosure. The wireless
communication system includes the wireless communication device
according to the present disclosure.
[0010] With the wireless communication device and the wireless
communication method according to the present disclosure, a system
throughput of a wireless network on a specific resource block in a
dense small cell deployment can be maximized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The above and other objectives, features and advantages will
be more easily understood with reference to the following
descriptions of embodiments of the present disclosure in
conjunction with the drawings. In the drawings, same or
corresponding reference numerals indicate same or corresponding
technical features or parts. In the drawings, sizes and relative
positions of units may not be drawn to scale.
[0012] FIG. 1 is a block diagram illustrating a functional
configuration of a wireless communication device according to an
embodiment of the present disclosure;
[0013] FIG. 2 is a flowchart illustrating a process of a wireless
communication method according to an embodiment of the present
disclosure;
[0014] FIG. 3 is a block diagram illustrating a functional
configuration of a wireless communication device according to an
embodiment of the present disclosure;
[0015] FIG. 4 is a schematic diagram illustrating a variation
characteristic that a total throughput of a network varies with a
transmission power of a target cell in a case that an overall
channel quality is good;
[0016] FIG. 5 is a sequence diagram illustrating a data transfer
between a user equipment and a cell base station in a case that a
wireless communication device according to an embodiment of the
present disclosure is integrated into the cell base station;
[0017] FIG. 6 is a block diagram illustrating a functional
configuration of a wireless communication device according to an
embodiment of the present disclosure;
[0018] FIG. 7 is a sequence diagram illustrating interactions
between base stations and interactions between a base station and a
user equipment in a case that a wireless communication device
according to an embodiment of the present disclosure is implemented
as a base station;
[0019] FIG. 8 is a flowchart illustrating a process of a wireless
communication method according to another embodiment of the present
disclosure;
[0020] FIG. 9 is a block diagram illustrating a functional
configuration of a wireless communication device according to
another embodiment of the present disclosure;
[0021] FIG. 10 is a sequence diagram illustrating a data transfer
between a user equipment and a base station and a data transfer
between a base station and a manager in a case that a wireless
communication device according to an embodiment of the present
disclosure is implemented as the manager; and
[0022] FIG. 11 is a sequence diagram illustrating an implementation
of a power allocating solution according to the present disclosure
in a wireless communication network.
DETAILED DESCRIPTION OF EMBODIMENTS
[0023] In the following, embodiments of the present disclosure are
described in conjunction with the drawings. It should be noted
that, for clarity, representations and descriptions of parts and
processes, which are independent of the present disclosure and
known by those skilled in the art, are omitted in the drawings and
the descriptions.
[0024] A high efficient power control solution is provided by the
present disclosure, for a scenario of different-frequency
deployment of small cell, so as to improve a system throughput.
Specifically, in an embodiment, with a wireless communication
device and a wireless communication method according to the present
disclosure, transmission power is determined in a corresponding
manner based on an overall channel quality of downlinks of a cell
on which a transmission power control is to be performed (also
referred to as "target cell" hereinafter) in a cell cluster and
other cells (also referred to as "non-target cell" hereinafter) in
the cell cluster on a specific resource block.
[0025] FIG. 1 is a block diagram illustrating a functional
configuration of a wireless communication device 100 according to
an embodiment of the present disclosure. The wireless communication
device 100 may be arranged independently as a controller
controlling transmission power of all cells in a cell cluster, or
arranged in each of cells in the cell cluster, or arranged in a
specified cell.
[0026] The wireless communication device 100 includes a
classification unit 101 and a control unit 102. The classification
unit 101 is configured to classify, based on channel qualities of
downlinks of a target cell and other cells in a cell cluster on a
specific resource block, an overall channel quality. For example,
the classification unit 101 may classify the overall channel
quality as good, normal, bad. The channel quality of the downlinks
of respective cells in the cell cluster on the specific resource
block may be characterized with any conventional indicators or
parameters in the art. And the overall channel quality may be
classified according to a predetermined classification criterion,
for example, by comparing these indicators or parameters with
thresholds predetermined based on practical experiences. In the
present disclosure, for example, the channel quality may be
characterized with signal to interference plus noise ratios (SINRs)
fed back by user equipments (UE) which occupy the specific resource
block and are within coverage ranges of the respective cells.
[0027] It is assumed that in a certain network scenario, a cell
cluster includes N cells SC.sub.n (n=1, 2, . . . , N). S resource
blocks (RBs) are shared by the cells in the cell cluster and an RB
of one cell can only be occupied by one user equipment. A user
equipment served by a target cell CS.sub.i and scheduled on a
resource block k is represented with UE.sub.i.sup.k, and the SINR
of UE.sub.i.sup.k is represented with .gamma..sub.i.sup.k.
Similarly, a user equipment served by a non-target cell CS.sub.j
(j=1, 2, . . . , N and j.noteq.i) and scheduled on the resource
block k is represented with UE.sub.j.sup.k, and the SINR of
UE.sub.j.sup.k is represented with .gamma..sub.j.sup.k. Then the
classification unit 101 may be configured to: classify an overall
channel quality of downlinks of the cell cluster on the resource
block k as good in a case that .gamma..sub.i.sup.k and
.gamma..sub.j.sup.k are both much greater than 1(>>1);
classify the overall channel quality of the downlinks of the cell
cluster on the resource block k as bad in a case that
.gamma..sub.i.sup.k and .gamma..sub.j.sup.k are both much less than
1(<<1); and classify the overall channel quality as normal in
other cases.
[0028] In an embodiment, the classification unit 101 may classify
the overall channel quality based on predetermined thresholds. For
example, for pre-stored thresholds Th1=0.5 and Th2=5, the
classification unit 101 may be configured to: classify the overall
channel quality of the downlinks of the cell cluster on the
resource block k as good in a case that .gamma..sub.i.sup.k>5
and .gamma..sub.j.sup.k>5, where it is considered that
.gamma..sub.i.sup.k and .gamma..sub.j.sup.k are both much greater
than 1; classify the overall channel quality as bad in a case that
.gamma..sub.i.sup.k<0.5 and .gamma..sub.j.sup.k<0.5, where it
is considered that .gamma..sub.i.sup.k and .gamma..sub.j.sup.k are
both much less than 1; and classify the overall channel quality as
normal in other cases.
[0029] The control unit 102 performs a control to determine
transmission power p.sub.i.sup.k by a power allocating method
adaptive to a classification determined by the classification unit
101, as a target transmission power of the target cell CS.sub.i on
the specific resource block k. In view of different system
requirements such as a requirement of maximizing a system
throughput or a requirement of ensuring an accurate reception of a
signal transferred under a bad channel quality, the control unit
102 may be configured to determine the target transmission power of
the target cell CS.sub.i on the specific resource block k by
different power allocating methods. For example, in a case that it
needs to be ensured that user equipments can reliably receive
downlink signals under a bad overall channel quality of downlinks
of cells in a cell cluster on a certain resource block, the control
unit 102 may be configured to determine power allocations for the
target cell on respective resource blocks in such a way that power
determined with a power determination method used for a resource
block with channel quality of downlinks classified as "bad" is
higher than that determined with a power determination method used
for a resource block with channel quality of downlinks classified
as "good". The specific method may be determined by those skilled
in the art as needed.
[0030] FIG. 2 is a flowchart illustrating a process of a wireless
communication method according to an embodiment of the present
disclosure. In step S201, based on channel qualities of downlinks
of a target cell CS.sub.i and other cells CS.sub.j (j=1, 2, . . . ,
N and j.noteq.i) in a cell cluster on a specific resource block k,
an overall channel quality is classified by a wireless
communication device 100 according to the present disclosure. For
example, the wireless communication device 100 may classified the
overall channel quality based on acquired SINRs .gamma..sub.n.sup.k
(n=1, 2, . . . , N) fed back to a cell base station from user
equipments UEs in the cell cluster which occupy the resource block
k. The SINRs .gamma..sub.n.sup.k may be used to characterize the
channel quality of the downlinks of the respective cells on the
resource block k.
[0031] For example, in step S201, the overall channel quality may
be classified as good, normal, bad. For example, the overall
channel quality may be determined by determining the relations
("much greater", "much less" and the like) of SINRs of the target
cell and other cells and 1. Whether it is "much greater" or "much
less" may be determined with a predetermined threshold. The details
thereof are omitted herein as they have already been described
above.
[0032] In step S202, a control is performed such that a target
transmission power of the target cell CS.sub.i on the specific
resource block k is determined by a power allocating method
adaptive to the classification of step S201. The Power allocating
methods adaptive to different classifications may be designed based
on system requirements, which have been described briefly above by
examples. Hereinafter, an embodiment of a power allocating solution
designed for maximizing a system throughput is described in detail
with reference to FIGS. 3 to 5.
[0033] FIG. 3 is a block diagram illustrating a functional
configuration of a wireless communication device 300 according to
an embodiment of the present disclosure. The wireless communication
300 includes a classification unit 301, a control unit 302 and a
calculation unit 303. Functions and structures of the
classification unit 301 are the same as those of the classification
unit 101 described in conjunction with FIG. 1, which are not
described in detail hereinafter.
[0034] The calculation unit 303 calculates inter-cell SINR of a
target cell CS.sub.i with regard to a respective non-target cell
CS.sub.j (j=1, 2, . . . , N and j.noteq.i) on a specific resource
block k, which is referred to as "inter-cell SINR" hereinafter. The
inter-cell SINR is defined as a ratio of interference of the target
cell on a certain non-target cell versus a sum of all interference
and noise the non-target cell is subjected to, on a certain
resource block. An inter-cell SINR .lamda..sub.i,j.sup.k of the
target cell CS.sub.i (a cell to be allocated with power) with
regard to a user equipment UE.sub.j.sup.k scheduled by the
non-target cell (a cell other than the target cell) CS.sub.j on the
resource block k may be represented with the following formula
(1):
.lamda. i , j k = p i k g i , j k I ( p - j k ) + .sigma. 2 ( 1 )
##EQU00001##
where p.sub.i.sup.k represents the transmission power of the target
cell CS.sub.i on the resource block k, and g.sub.i,j.sup.k
represents a channel gain from the target cell CS.sub.i to the user
equipment UE.sub.j.sup.k of the non-target cell CS.sub.j.
Therefore, the numerator p.sub.i.sup.k g.sub.i,j.sup.k represents
the interference on the user equipment UE.sub.j.sup.k by a
transmission of the cell CS.sub.i, i.e. the received power of the
transmission of the cell CS.sub.i at the user equipment
UE.sub.j.sup.k, which may be obtained by the user equipment
UE.sub.j.sup.k via a measurement. In addition, I(p.sub.-j.sup.k)
represents the interference on the non-target cell CS.sub.j from
all other cells in the cell cluster on the resource block k, and
.sigma..sup.2 represents all noises the non-target cell CS.sub.j is
subjected to. I(p.sub.-j.sup.k) may be calculated according to the
following formula (2):
I ( p - j k ) = n .noteq. j , n = 1 N p n k g n , j k ( 2 )
##EQU00002##
[0035] It can be seen that, I(p.sub.-j.sup.k) is a sum of received
powers of transmissions of all the cells other than the non-target
cell CS.sub.j at the user equipment UE.sub.j.sup.k, on the resource
block k. Similarly, the received power may be obtained by the user
equipment UE.sub.j.sup.k via a measurement.
[0036] In an actual implementation, the value of I(p.sub.-j.sup.k)
may not be calculated exactly. The denominator of formula (1)
indicates a sum of power of interference and noises, i.e., useless
power. Therefore, the denominator can be obtained as long as the
user equipment UE.sub.j.sup.k reports its SINR and the received
power of its serving base station. This manner is more simple and
accurate than a calculation with formula (2).
[0037] After calculating the inter-cell SINR of the target cell
CS.sub.i with regard to each non-target cell CS.sub.j on the
resource block k, the calculation unit 303 may further calculate a
sum of the inter-cell SINRs of the target cell CS.sub.i with regard
to all of the non-target cells CS.sub.j (j=1, 2, . . . , N and
j.noteq.i). The sum may be represented as
j .noteq. i .lamda. i , j k . ##EQU00003##
And the calculated sum of the inter-cell SINRs,
j .noteq. i .lamda. i , j k , ##EQU00004##
may be used in the power allocating solution described below.
[0038] In order to maximize the system throughput, the control unit
302 is configured to perform a control to determine a target
transmission power of the target cell on the specific resource
block by a power allocating method adaptive to a classification
made by the classification unit 301.
[0039] Specifically, the control unit 301 may be configured to
determine whether the sum of the inter-cell SINRs,
j .noteq. i .lamda. i , j k , ##EQU00005##
is less than 1, in a case that the overall channel quality is
classified as good, for example, when .gamma..sub.i.sup.k an
.gamma..sub.j.sup.k are both much greater than 1. If it is
determined that the sum of the inter-cell SINRs is not less than 1,
the target transmission power may be determined by decreasing, by a
certain step length, the transmission power of the target cell
CS.sub.i on the resource block k. In addition, in some embodiments,
if it is determined by the control unit 302 that the sum of the
inter-cell SINRs is less than 1, the target transmission power of
the target cell CS.sub.i on the resource block may be determined by
making a first-order partial derivative of a total throughput
R.sup.k of all cells in the cell cluster on the specific resource
block k with respect to the transmission power p.sub.i.sup.k of the
target cell CS.sub.i on the resource block k equal to 0.
[0040] In the following, description is to be made in conjunction
with specific formulas. In the network scenario assumed in the
above, the total throughput R.sup.k of all of the cells in the cell
cluster on the resource block k may be represented with, for
example, formula (3):
R k = i = 1 N log 2 ( 1 + p i k g i , i k j .noteq. i , j = 1 N p j
k g j , i k + .sigma. 2 ) ( 3 ) ##EQU00006##
where meanings of superscripts and subscripts of parameters are
similar to those described in the above and thus are not described
repeatedly herein. In an embodiment in which a quality of downlinks
is represented with a SINR, first-order and second-order partial
derivatives of R.sup.k with respect to the transmission power
p.sub.i.sup.k may be represented with formula (4) and formula
(5):
.differential. R k .differential. p i k = 1 1 + .gamma. i k g i , i
k I ( p - i k ) + .sigma. 2 + j .noteq. i N 1 1 + .gamma. j k ( - p
j k g j , j k ( I ( p - j k ) + .sigma. 2 ) 2 ) g i , j k = .gamma.
i k p i k ( 1 + .gamma. i k ) - j .noteq. i N g i , j k ( .gamma. j
k ) 2 p j k g j , j k ( 1 + .gamma. j k ) , p i k .noteq. 0 and p j
k .noteq. 0 ( 4 ) .differential. 2 R k .differential. ( p i k ) 2 =
[ - 1 ( 1 + .gamma. i k ) 2 g i , i k I ( p - i k ) + .sigma. 2 ] g
i , i k I ( p - i k ) + .sigma. 2 - j .noteq. i N g i , j k p j k g
j , j k 2 .gamma. j k ( 1 + .gamma. j k ) - ( .gamma. j k ) 2 ( 1 +
.gamma. i k ) 2 [ - p j k g j , j k ( I ( p - j k ) + .sigma. 2 ) 2
] g i , j k = - ( .gamma. i k ) 2 ( p i k ) 2 ( 1 + .gamma. i k ) 2
+ j .noteq. i N ( g i , j k p j k g j , j k ) 2 ( .gamma. j k ) 4 +
2 ( .gamma. j k ) 3 ( 1 + .gamma. j k ) 2 , p i k .noteq. 0 and p j
k .noteq. 0 ( 5 ) ##EQU00007##
[0041] Formula (4) and formula (5) may be simplified in a case that
the overall channel quality is classified as good, i.e.
.gamma..sub.i.sup.k and .gamma..sub.j.sup.k, are both much greater
than 1 (generally, .gamma..sub.i.sup.k and .gamma..sub.j.sup.k are
both much greater than 1 in a case that the overall channel quality
of the downlinks is good). In addition, by substituting the
inter-cell SINR .lamda..sub.i,j.sup.k, the first-order and
second-order partial derivatives of the total throughput R.sup.k
with respect to p.sub.i.sup.k may be converted into:
.differential. R k .differential. p i k .apprxeq. 1 P i k - j
.noteq. i N g i , j k .gamma. j k p j k g j , j k = 1 - j .noteq. i
N .lamda. i , j k p i k ( 6 ) .differential. 2 R k .differential. (
p i k ) 2 .apprxeq. - 1 ( P i k ) 2 + j .noteq. i N ( g i , j k
.gamma. j k p j k g j , j k ) 2 = - 1 ( P i k ) 2 + j .noteq. i N [
g i , j k I ( p - j k ) + .sigma. 2 ] 2 = j .noteq. i N ( .lamda. i
, j k ) 2 - 1 ( P i k ) 2 ( 7 ) ##EQU00008##
[0042] With formulas (6) and (7), the variation characteristic of a
total throughput of the network varying with the transmission power
of the target cell may be obtained. FIG. 4 is a schematic diagram
illustrating the variation characteristic of the total throughput
of the network varying with the transmission power of the target
cell in a case that .gamma..sub.i.sup.k and .gamma..sub.j.sup.k are
both much greater than 1.
[0043] If the sum of the inter-cell SINRs,
j .noteq. i N .lamda. i , j k , ##EQU00009##
is less than 1 (i.e.
.differential. R k .differential. p i k > 0 ) , ##EQU00010##
then .lamda..sub.i,j.sup.k<1 for any values of j. Then
j .noteq. i N ( .lamda. i , j k ) 2 ##EQU00011##
is less than 1,
.differential. 2 R k .differential. ( p i k ) 2 < 0.
##EQU00012##
It can be seen that, R.sup.k(p.sub.i.sup.k) is a convex function,
as shown in (a) of FIG. 4. Therefore, when
.differential. R k .differential. p i k = 0 , ##EQU00013##
R.sup.k(p.sub.i.sup.k) has an optimum solution, which is
represented by "P". Otherwise, if the sum of inter-cell SINRs,
j .noteq. i N .lamda. i , j k , ##EQU00014##
is not less than 1, then the function R.sup.k(p.sub.i.sup.k) is a
concave function, as shown in (b) of FIG. 4, of which an optimum
solution can not obtained directly.
[0044] Similarly, in a case that the overall channel quality is
classified as bad, for example, in a case that the channel quality
is represented with a SINR and .gamma..sub.i.sup.k and
.gamma..sub.j.sup.k are both much less than 1 (i.e.
.gamma..sub.i.sup.k<<1 and .gamma..sub.h.sup.k<<1), it
may be deduced that
.differential. R k .differential. p i k > 0 and .differential. 2
R k .differential. ( p i k ) 2 < 0 ##EQU00015##
based on formulas (4) and (5). Therefore, an optimum solution of
R.sup.k(p.sub.i.sup.k) may also be obtained when
.differential. R k .differential. p i k = 0. ##EQU00016##
Therefore, the control unit 302 may be configured to perform a
control to, in a case that the overall channel quality is
classified as bad, determine the target transmission power of the
target cell CS.sub.i on the resource block k by making the
first-order partial derivative of the total throughput R.sup.k of
all of the cells in the cell cluster on the resource block k with
respect to the transmission power p.sub.i.sup.k of the target cell
CS.sub.i on the resource block k equal to 0.
[0045] In a case that the overall channel quality is normal, for
example, in a case that when the channel quality are represented by
.gamma..sub.i.sup.k and .gamma..sub.j.sup.k, .gamma..sub.i.sup.k
and .gamma..sub.j.sup.k are neither both much less than 1 nor both
much greater than 1, it is difficult to directly determine the
variation characteristic of R.sup.k(p.sub.i.sup.k) based on the
SINRs .gamma..sub.i.sup.k and .gamma..sub.j.sup.k and the sum of
inter-cell SINRs,
j .noteq. i N .lamda. i , j k . ##EQU00017##
Therefore, the variation characteristic of R.sup.k(p.sub.i.sup.k)
may be obtained by directly calculating the first-order and
second-order partial derivatives of R.sup.k with respect to
p.sub.i.sup.k by, for example, formula (4) and formula (5), and
comparing them with 0 respectively.
[0046] In an embodiment, the calculation unit 303 may have the
following function: compare values of the first-order and
second-order partial derivatives of the total throughput R.sup.k of
all of the cells in the cluster on the resource block k with
respect to the transmission power p.sub.i.sup.k of the target cell
CS.sub.i on the resource block k,
.differential. R k .differential. p i k and .differential. 2 R k
.differential. ( p i k ) 2 , ##EQU00018##
with 0, and provide the comparison result to the control unit 302.
The control unit 302 may be configured to perform a control to
determine the target transmission power of the target cell CS.sub.i
on the resource block k by making the first-order partial
derivative
.differential. R k .differential. p i k = 0 , ##EQU00019##
in a case that the overall channel quality is classified as normal
and it is determined by the calculation unit 303 via the comparison
that the value of the first-order partial derivative
.differential. R k .differential. p i k ##EQU00020##
is greater than 0 and the value of the second-order partial
derivative
.differential. 2 R k .differential. ( p i k ) 2 ##EQU00021##
is less than 0. In addition, the control unit 302 may be further
configured to perform a control to determine the target
transmission power by decreasing, by a certain step length, the
transmission power of the target cell CS.sub.i on the resource
block k, in a case that the overall channel quality is classified
as normal and it is determined by the calculation unit 303 via the
comparison that the value of the first-order partial derivative
.differential. R k .differential. p i k ##EQU00022##
is less than 0.
[0047] In the following, taking an embodiment of integrating
(implementing) the wireless communication device 300 into (as) a
cell base station as an example, a data transfer between a user
equipment and a cell base station in a wireless communication
system using a power allocating solution according to the present
disclosure is described in conjunction with FIG. 5.
[0048] FIG. 5 is a sequence diagram illustrating a data transfer
between a user equipment and a cell base station in a case that the
wireless communication device 300 according to the embodiment of
the present disclosure is integrated into the cell base
station.
[0049] It can be seen from the above analysis that, the wireless
communication device 300 needs to acquire the following contents to
select a proper power allocating solution: SINRs
.gamma..sub.n.sup.k (n=1, 2, . . . , N) of the cells in the cell
cluster on the resource block k, and inter-cell SINRs
.lamda..sub.i,j.sup.k (referred to as "inter-cell SINR"
hereinafter) of the target cell CS.sub.i with respect to all of the
other cells CS.sub.j (j=1, 2, . . . , N and j.noteq.i) on the
resource block k.
[0050] Here, the SINR .gamma..sub.n.sup.k may be obtained by
feeding back from user equipments to their serving cells and
interactions between cells. For example, in FIG. 5, user equipments
UE.sub.i.sup.k in the target cell scheduled on the resource block k
and UE.sub.j.sup.k in other cells scheduled on the resource block k
measure SINRs of their serving cells on the resource block k,
.gamma..sub.i.sup.k and .gamma..sub.j.sup.k, and feedback
.gamma..sub.i.sup.k and .gamma..sub.j.sup.k to base stations of
their serving cells. In the embodiment, the non-target cell
CS.sub.j provides its SINR .gamma.) to the target cell CS.sub.i.
Then, the wireless communication device 300 included in the base
station of the target cell CS.sub.i may classify an overall channel
quality of downlinks on the resource block k.
[0051] In addition, it can be seen from definition formulas (1) and
(2) of inter-cell SINR .lamda..sub.i,j.sup.k that, interferences on
the cell CS.sub.j by all cells other than the cell CS.sub.j on the
resource block k, i.e. received power p.sub.m,j.sup.k (m=1, 2, . .
. , N and m.noteq.j) received by the user equipment UE.sub.j.sup.k
respectively from all the cells other than the cell CS.sub.j,
p.sub.m,j.sup.k=p.sub.m.sup.kg.sub.m,j.sup.k, needs to be acquired
to calculate .lamda..sub.i,j.sup.k. In FIG. 5, the user equipment
UE.sub.j.sup.k measures p.sub.m,j.sup.k and delivers
p.sub.m,j.sup.k to a base station of the cell CS.sub.j. Then, the
inter-cell SINR .lamda..sub.i,j.sup.k may be calculated in the base
station of the cell CS.sub.j according to formulas (1) and (2)
using all of received power p.sub.m,j.sup.k (m=1, 2, . . . , N and
m.noteq.j) received. Then, the cell CS.sub.j provides
.lamda..sub.i,j.sup.k to the cell CS.sub.i, for the wireless
communication device 300 included in the base station of the target
cell CS.sub.i to calculate the sum of inter-cell SINRs,
j .noteq. i N .lamda. i , j k . ##EQU00023##
[0052] In a case that the overall channel quality is classified as
normal, it is needed to compare respectively, with zero, the values
of the first-order and second-order partial derivatives of the
total throughput R.sup.k of all the cells in the cell cluster on
the resource block k with respect to the transmission power
p.sub.i.sup.k of the target cell CS.sub.i on the resource block
k,
.differential. R k .differential. p i k and .differential. 2 R k
.differential. ( p i k ) 2 . ##EQU00024##
Therefore, it can be seen from formulas (4) and (5) that, the
wireless communication device 300 needs to further obtain channel
gains g.sub.i,j.sup.k, g.sub.i,i.sup.k, and g.sub.j,j.sup.k. It can
be appreciated by those skilled in the art that these gains may be
obtained in various known manners, for example, by calculating a
ratio of transmission power versus corresponding received
power.
[0053] After obtaining sufficient data, the wireless communication
device 300 included in the target cell CS.sub.i may determine a
target transmission power with a corresponding method. In a case
that the method in which the first-order derivative
.differential. R k .differential. p i k = 0 ##EQU00025##
is adopted to determine the target transmission power, the
following deduced formula (8) may be adopted:
.differential. R k .differential. p i k = 1 1 + .gamma. i k g i , i
k I ( p - i k ) + .sigma. 2 + j .noteq. i N 1 1 + .gamma. j k ( - p
j k g j , j k ( I ( p - j k ) + .sigma. 2 ) 2 ) g i , j k = .gamma.
i k 1 + .gamma. i k 1 p i k - 1 p i k j .noteq. i N .gamma. j k 1 +
.gamma. j k .lamda. i , j k = 0 .gamma. i k 1 + .gamma. i k = j
.noteq. i N .gamma. j k 1 + .gamma. j k .lamda. i , j k p i k = A H
( 1 - A ) , where A = j .noteq. i N .gamma. j k 1 + .gamma. j k
.lamda. i , j k , H = g i , i k I ( p - i k ) + .sigma. 2 ( 8 )
##EQU00026##
where meanings of symbols are the same as or similar to those
described in the above, and thus are not described herein.
[0054] It should be noted that, the timing sequence of measuring,
feeding back and providing related parameters and the timing
sequence of operations of classification, calculation and
determination, etc., shown in FIG. 5 are only examples without
intending to limit the present disclosure, and can be adjusted in
any ways as needed. In addition, a subject performing the
operations such as classification, calculation and determination
may be changed as needed. For example, the inter-cell SINR may be
directly calculated by the user equipment or may be all calculated
in the base station of the target cell.
[0055] With the wireless communication device and the wireless
communication method corresponding to the operations performed by
the wireless communication device described above, a target
transmission power of a target cell on a specific resource block
may be determined by a power allocating method adaptive to a
classification of an overall channel quality of downlinks on the
specific resource block, thereby maximizing a system throughput of
a wireless network on the specific resource block in a dense small
cell deployment.
[0056] In the following, another embodiment according to the
present disclosure is described in conjunction with FIGS. 6 to 10.
FIG. 6 is a block diagram illustrating a functional configuration
of a wireless communication device 600 according to an embodiment
of the present disclosure. The wireless communication device 600
includes a classification unit 601, an allocating unit 602 and a
control unit 603.
[0057] The classification unit 601 is configured to classify a user
equipment UE (classifying the user equipment into different types)
based on average channel quality of downlinks to the user equipment
UE in a cell cluster in a predetermined time period. The average
channel quality of the user equipment UE in the predetermined time
period may be acquired by using any type of data capable of
indicating the channel quality of the downlink. The average channel
quality of the downlink to the user equipment UE in the
predetermined time period may be characterized by, for example, but
not limited to, an average SINR of the user equipment UE in the
predetermined time period.
[0058] FIG. 7 is a sequence diagram illustrating an interaction
between a base station and a user equipment and an interaction
between the base station and the wireless communication device 600
(manager) in a case that the wireless communication device 600
according to the embodiment of the present disclosure is arranged
separately from the base station (in other words, implemented as a
manager of the cell cluster). A cell CS represents each of the
cells in a cell cluster, and UE represents a user equipment served
by the cell CS. The user equipment UE measures a SINR .gamma. which
can characterize the quality of downlinks to the user equipment UE,
and feeds .gamma. back to a base station of its serving cell. The
base station may calculate an average value .gamma. of SINRs
received in the predetermined time period and provide the obtained
average value to a manager. Alternatively, the base station may
directly provide the SINRs fed back from the user equipment to the
manager, and the manager calculates the average value of the SINRs
centrally. Then, the manager may classify the user equipment based
on the calculated average value.
[0059] In an example, the classification unit 601 may be configured
to: classify the user equipment into a first type (also referred to
as a type of "good" hereinafter) in a case that the average SINR is
much greater than 1; classify the user equipment into a second type
(also referred to as a type of "bad" hereinafter) in a case that
the average SINR is much less than 1; and classify the user
equipment into a third type (also referred to as a type of "normal"
hereinafter) in a case that the average SINR is neither much
greater than nor much less than 1.
[0060] In a specific implementation, predetermined threshold Th3
and Th4 (Th3<Th4) may be set previously. If the average SINR
.gamma.>Th4, it is considered that .gamma.>>1 and the user
equipment is determined to be in the first type. If .gamma.<Th3,
it is considered that .gamma.<<1 and the user equipment is
determined to be in the second type. If
Th3.ltoreq..gamma..ltoreq.Th4, it is considered that .gamma. is
neither much greater than nor much less than 1, and the user
equipment is determined to be in the third type. For example, Th3
and Th4 may have the same values as Th1 and Th2 respectively. For
example, Th3=0.5 and Th4=5.
[0061] In an example, if a cell cluster includes totally 12 user
equipments UE1 to UE12, and Th3=1 and Th4=10, then classification
results of the user equipments are as shown in Table 1:
TABLE-US-00001 TABLE 1 USER EQUIPMENT .gamma. TYPE UE1 0.4 bad UE2
0.3 bad UE3 5 normal UE4 11 good UE5 0.8 bad UE6 4.2 normal UE7
10.8 good UE8 0.6 bad UE9 3.5 normal UE10 4.6 normal UE11 7.8
normal UE12 13.4 good
[0062] After the classification unit 601 classifies the user
equipment UE based on the average channel quality in the
predetermined time period, the allocating unit 602 may allocate a
resource block set to the user equipment at least partly based on
the type of the user equipment. In the embodiment, the allocating
unit 602 may allocate a same resource block set for user equipments
of the same classification. For example, in a case of totally
having 50 resource blocks, as shown in FIG. 2, user equipments of
the type of "bad" may be allocated with resource blocks RB1 to RB
10, user equipments of the type of "normal" may be allocated with
resource blocks RB15 to RB40, and user equipments of the type of
"good" may be allocated with resource blocks RB41 to RB50.
TABLE-US-00002 TABLE 2 Type of user equipment RB BAD RB1~RB10
NORMAL RB15~RB40 GOOD RB41~RB50
[0063] Table 2 shows an example of a resource block set allocation
to the user equipments. In a specific implementation, the resource
block set may be allocated to user equipments of the same type
based on different requirements and using different criterions. For
example, the allocating unit 602 may be configured to allocate a
resource block set to a user equipment at least partly based on the
numbers of user equipments of different types. Besides, for
example, the allocating unit 602 may be further configured to
allocate a resource block set at least partly based on service
requirements of the user equipments of different types.
[0064] As shown in FIG. 7, in addition to the average value of the
SINRs, the base station may further provide information such as
service requirements of the user equipments to the manager. After
classifying the user equipments, the manager may allocate resource
block sets to the user equipments of different types by combining
information such as the types of the user equipments, the numbers
of the user equipments of different types, and the service
requirements of the user equipments of different types. Then, the
manager informs the base stations of the cells of an allocating
result of resource block sets.
[0065] Upon receiving the allocating results of resource block set,
the base station schedules user equipments of a corresponding type
on a resource block based on the allocating result. In this way,
the user equipment UE communicates on the allocated resource
block.
[0066] It should be noted that, the timing sequence of measuring,
feeding back and providing related parameters and the timing
sequence of operations such as classification, calculation and
determination shown in FIG. 7 are only examples without intending
to limit the present disclosure, and can be adjusted in any ways as
needed. In addition, a subject performing the operations such as
classification, calculation and determination may be changed as
needed.
[0067] The control unit 603 is configured to perform a control to
determine a target transmission power of the target cell on the
specific resource block by a power allocating method adaptive to a
classification of a user equipment UE.sub.i.sup.k scheduled by the
target cell CS.sub.i (a cell on which a power control is to be
performed) on the specific resource block k.
[0068] In view of different system requirements such as a
requirement of maximizing a system throughput or a requirement of
ensuring an accurate reception of a signal transferred under a bad
channel quality, the control unit 603 may be configured to
determine the target transmission power of the target cell CS.sub.i
on the specific resource block k by different power allocating
methods. For example, in a case that a user equipment even
classified as the type of "bad" needs to be ensured to receive a
downlink signal reliably, the control unit 603 may be configured to
determine power of the target cell on the resource blocks allocated
to user equipments of different types in such a way that the power
determined with a power determination method for a resource block
occupied by user equipments of the type of "bad" is higher than the
power determined with a power determination method for a resource
block occupied by user equipments of the type of "good". The
specific method may be determined by those skilled in the art as
needed.
[0069] FIG. 8 is a flowchart illustrating a process of a wireless
communication method according to an embodiment of the present
disclosure. In step S801, a user equipment is classified based on
average channel quality of downlinks to the user equipment in a
cell cluster in a predetermined time period. In step S802, a
resource block set is allocated to the user equipment at least
partly based on a classification of the user equipment, wherein a
same resource block set is allocated to user equipments of the same
classification. And in step S803, a control is performed to
determine a target transmission power of the target cell on the
specific resource block by a power allocating method adaptive to a
classification of the user equipment scheduled by the target cell
on the specific resource block. The details of the respective steps
have been described in conjunction with the wireless communication
device 600 above, and thus are not described herein.
[0070] FIG. 9 is a block diagram illustrating a functional
configuration of a wireless communication device 900 according to
an embodiment of the present disclosure. The wireless communication
device 900 includes: a classification unit 901, an allocating unit
902, a control unit 903 and a calculation unit 904. Functions and
structures of the classification unit 901 and the allocating unit
902 are the same as those of the classification 601 and the
allocating unit 602 described in conjunction with FIG. 6, and thus
are not described in detail hereinafter.
[0071] The calculation unit 904 calculates inter-cell SINRs of the
target cell CS.sub.i with respect to each non-target cell CS.sub.j
(j=1, 2, . . . , N and j.noteq.i) on a specific resource block k,
which is referred to as "inter-cell SINR" hereinafter. Inter-cell
SINR is defined as a ratio of interference of the target cell on a
certain non-target cell versus a sum of all interference and noise
the non-target cell is subjected to, on a certain resource block.
An inter-cell SINR .lamda..sub.i,j.sup.k of the target cell
CS.sub.i to the user equipment UE.sub.j.sup.k scheduled by the
non-target cell CS.sub.j on the resource block k may be represented
with the above formula (1), and thus is not described repeatedly
herein. The inter-cell SINR .lamda..sub.i,j.sup.k may be calculated
based on received power at the user equipment UE.sub.j.sup.k from a
transmission of the cell CS.sub.i, which is obtained by the user
equipment UE.sub.j.sup.k via a measurement, and a sum of received
power on the user equipment UE.sub.j.sup.k from transmissions of
each of cells other than the non-target cell CS.sub.j on the
resource block k, which is obtained by the user equipment
UE.sub.j.sup.k via a measurement.
[0072] After calculating the inter-cell SINR of the target cell
CS.sub.i with respect to each non-target cell CS.sub.j on the
resource block k, the calculation unit 904 may further calculate a
sum of the inter-cell SINRs of the target cell CS.sub.i with
respect to all of the non-target cells CS.sub.j (j=1, 2, . . . , N
and j.noteq.i). The sum may be represented as
j .noteq. i .lamda. i , j k . ##EQU00027##
The calculated sum of the inter-cell SINRs,
j .noteq. i .lamda. i , j k , ##EQU00028##
may be used in a power allocating solution described below.
[0073] The control unit 903 may be configured, based on the object
of maximizing a system throughput, to perform a control to
determine whether the sum of the inter-cell SINRs,
j .noteq. i .lamda. i , j k , ##EQU00029##
is less than 1 in a case that the user equipment UE.sub.i.sup.k is
of the type of good ("the first type"); and determine a target
transmission power by decreasing, by a certain step length, the
transmission power p.sub.i.sup.k of the target cell CS.sub.i on the
resource block k if it is determined that the sum of the inter-cell
SINRs,
j .noteq. i .lamda. i , j k , ##EQU00030##
is not less than 1; or determine a target transmission power of the
target cell CS.sub.i on the specific resource block by making a
first-order partial derivative of a total throughput R.sup.k of
cells in the cell cluster on the resource block k with respect to
the transmission power p.sub.i.sup.k of the target cell CS.sub.i on
the specific resource block k equal to 0, if it is determined that
the sum of the inter-cell SINRs,
j .noteq. i .lamda. i , j k , ##EQU00031##
is less than 1.
[0074] Actually, the wireless communication device 900 corresponds
to the wireless communication device 300 described above in
conjunction with the FIG. 3 in that: the wireless communication
device 300 selects a proper power determination method based on a
classification (for example, by comparing .gamma..sub.i.sup.k and
.gamma..sub.j.sup.k respectively with 1) of an overall channel
quality; while the wireless communication device 900 classifies the
user equipment based on a channel quality of downlinks on a whole
frequency band, then allocates a same resource block set to user
equipments of the same classification, and selects a proper power
determination method based on the classifications of the user
equipments. Actually, the user equipment classification and
resource block allocating performed by the latter wireless
communication device ensures, in a probability as high as possible,
that downlinks to the user equipments scheduled by different
serving cells on the same resource block have similar quality. That
is to say, in a case that the quality of the downlink is
characterized with a SINR, the user equipment classification and
resource block allocating performed by the latter wireless
communication device ensure, in a probability as high as possible,
that a comparison result between .gamma..sub.i.sup.k and 1 is the
same as a comparison result between .gamma..sub.i.sup.k and 1 (for
example, .gamma..sub.i.sup.k and .gamma..sub.j.sup.k are both much
greater than 1, or both much less than 1).
[0075] Therefore, in an embodiment, the control unit 903 may also
be configured to perform a control to determine the target
transmission power of the target cell CS.sub.i on the resource
block k by making the first-order partial derivative of the total
throughput R.sup.k of all the cells in the cell cluster on the
resource block k with respect to the transmission power
p.sub.i.sup.k of the target cell CS.sub.i on the specific resource
block k equal to 0, in a case that the user equipment is of the
type of "bad" ("the second type"), that is, in a high probability,
.gamma..sub.i.sup.k of the user equipment UE.sub.i.sup.k and
.gamma..sub.j.sup.k of a user equipment UE.sub.j.sup.k scheduled on
the same resource block k as the user equipment UE.sub.i.sup.k are
both much less than 1.
[0076] If the user equipment UE.sub.i.sup.k is of the type of
"normal" ("the third type"), it can be seen that, in a high
probability, the quality of downlinks to the user equipment and the
quality of downlinks to a user equipment UE.sub.j.sup.k scheduled
on the same resource block k as the user equipment UE.sub.i.sup.k
are both normal. For example, the SINRs .gamma..sub.i.sup.k and
.gamma..sub.j.sup.k may both be neither much greater than 1 nor
much less than 1. In this case, similar to the wireless
communication device 300, the calculation unit 904 of the wireless
communication device 900 may be configured to compare values of
first-order and second-order partial derivatives of the total
throughput R.sup.k of all of the cells in the cell cluster on the
resource block k with respect to the transmission power
p.sub.i.sup.k of the target cell CS.sub.i on the resource k with
zero. And the control unit 903 may be configured to determine the
target transmission power of the target cell CS.sub.i on the
resource block k by making the first-order partial derivative equal
to 0, in a case that the user equipment is of the type of "normal"
("the third type") and it is determined by the calculation unit 904
via the comparison that the value of the first-order partial
derivative is greater than 0 and the value of the second-order
partial derivative is less than 0.
[0077] Alternatively, the control unit 903 may be configured to
determine a target transmission power by decreasing, by a certain
step length, transmission power of a target cell on a specific
resource block in a case that the user equipment is of the type of
"normal" ("the third type") and it is determined by the calculation
unit 904 via the comparison that the value of the first-order
partial derivative is less than 0.
[0078] In the following, still taking the embodiment in which the
wireless communication device 900 is implemented as a network
manager as an example, a data transfers between a user equipment
and a cell base station and between a cell base station and the
manager, in a wireless communication system using the power
allocating solution according to the present disclosure are
described in conjunction with FIG. 10.
[0079] FIG. 10 is a sequence diagram illustrating data transfers
between a user equipment and a base station and between a base
station and a manager in a case that the wireless communication
device 900 is implemented as a manager according to the embodiment
of the present disclosure. Transfers and operations shown in FIG.
10 are performed following the resource block allocating operation
shown in FIG. 7. In other words, as compared with FIG. 7, user
equipments in FIG. 10 have been scheduled on specific resource
blocks (k) adaptive to types of the user equipments.
[0080] The embodiment shown in FIG. 10 differs from the embodiment
shown in FIG. 5 in that: in the embodiment shown in FIG. 10, it is
unnecessary to determine an overall downlinks since types of the
user equipments have been determined; in addition, the operations
of calculating the inter-cell SINR .lamda..sub.i,j.sup.k, the sum
of inter-cell SINRs,
j .noteq. i N .lamda. i , j k , ##EQU00032##
and various gains (such as g.sub.i,j.sup.k, g.sub.i,i.sup.k, and
g.sub.j,j.sup.k) are all done at the manager. And the operation of
determining the target transmission power of the target cell
CS.sub.i is done at the manager. Then, the target cell CS.sub.i is
informed of the determined target transmission power.
[0081] Due to these differences, the data transfer is changed
accordingly. For example, after a user equipment UE.sub.j.sup.k of
a non-target cell CS delivers to the cell CS.sub.j the measured
received power p.sub.m,j.sup.k (m=1, 2, . . . , N and m.noteq.j)
which are received from all cells other than the cell CS.sub.j, the
cell CS.sub.j provides the received power to the manager for
calculating by the manager the sum of inter-cell SINRs,
j .noteq. i N .lamda. i , j k , ##EQU00033##
and various gains.
[0082] The operation of "determining the power" performed in the
manager generally includes: all operations in the above control
unit 903, and the operations in the calculation unit 904 of
calculating the values of the first-order partial derivative
.differential. R k .differential. p i k ##EQU00034##
and the second-order partial derivative
.differential. 2 R k .differential. ( p i k ) 2 , ##EQU00035##
comparing the values of the first-order and second-order partial
derivatives with zero, and the like.
[0083] It should be noted that, the timing sequence of measuring,
feeding back and providing related parameters and the timing
sequence of operations such as calculation and determination shown
in FIG. 10 are only examples without intending to limit the present
disclosure, and can be adjusted in any ways as needed. In addition,
in a case that the wireless communication device 900 is implemented
as a base station (being included in a base station), similar data
transmission is made between a user equipment and the base station
and between base stations.
[0084] FIG. 11 is a sequence diagram illustrating an implementation
of a power allocating solution according to the present disclosure
in a wireless communication network. As shown in FIG. 11, in a time
period of implementing the solution, the power allocating solution
according to the present disclosure, a state determination and a
power allocating are performed based on information acquired in
preceding time, and subsequently, the information acquisition,
state determination and power allocating are performed
iteratively.
[0085] With the wireless communication devices and the wireless
communication method corresponding to the operations performed by
the wireless communication devices described above, a user
equipment may be classified based on average quality of downlinks
in a predetermined time period, and a same resource block set is
provided to user equipments of the same classification in a cell
cluster. Then, a target transmission power of the target cell on a
specific resource block is determined by a power allocating method
adaptive to the type of the user equipment, thereby maximizing a
system throughput of a wireless network on the specific resource
block under a dense small cell deployment.
[0086] Furthermore, a computer program may be created, which enable
hardware (such as Central Processing Unit (CPU), a Read-Only Memory
(ROM) and a Random Access Memory (RAM)) mounted in a base station,
a communication terminal or a network manager to perform functions
equivalent to those of parts of the base station, the communication
terminal or the network manager. In addition, a storage medium
storing the computer program is also provided.
[0087] In the above description of the embodiments of the present
disclosure, a feature described and/or shown for an embodiment may
be used in one or more other embodiments in a same or similar
manner, and may be combined with a feature of another embodiments
or replace a feature of another embodiment.
[0088] It should be noted that, the term "include/contain", when
used in the present disclosure, is to specify the presence of a
feature, an element, a step or a component, but do not exclude the
presence or addition of one or more other features, elements, steps
or components.
[0089] In addition, the method according to the present disclosure
is not limited to be performed in the time order described in the
description, and may be performed sequentially, in parallel or
independently in other time orders. Therefore, the technical scope
of the present disclosure is not limited to the performing order of
the method described in the specification.
[0090] In the above, the present disclosure is disclosed with the
descriptions of the embodiments thereof. However, it should be
understood that, various modifications, improvements or equivalents
thereof may be designed for the present disclosure by those skilled
in the art within the spirit and scope of the appended claims.
These modifications, improvements or equivalents thereof should be
considered to fall within the protection scope of the present
disclosure.
[0091] The following embodiments are further described in the
present disclosure:
[0092] 1. A wireless communication device, including:
[0093] a classification unit, configured to classify, based on
channel qualities of downlinks of a target cell and other cells in
a cell cluster on a specific resource block, an overall channel
quality; and
[0094] a control unit, configured to perform a control to determine
a target transmission power of the target cell on the specific
resource block by a power allocating method adaptive to a
classification of the overall channel quality.
[0095] 2. The wireless communication device according to embodiment
1, wherein according to a predetermined classification criterion,
the classification of the overall channel quality includes: good,
normal, and bad.
[0096] 3. The wireless communication device according to embodiment
2, wherein each of the channel qualities is characterized by a
SINR.
[0097] 4. The wireless communication device according to embodiment
3, wherein the predetermined classification criterion includes:
[0098] the overall channel quality is classified as good in a case
that SINRs of the target cell and the other cells are all much
greater than 1;
[0099] the overall channel quality is classified as bad in a case
that SINRs of the target cell and the other cells are all much less
than 1; and
[0100] the overall channel quality is classified as normal in other
cases.
[0101] 5. The wireless communication device according to any one of
embodiments 1-4, further including a calculation unit, wherein the
calculation unit is configured to calculate an inter-cell SINR of
the target cell with respect to a first other cell on the specific
resource block, and the inter-cell SINR is defined as: a ratio of
the interference on the first other cell from the target cell
versus a sum of all interference and noise the first other cell is
subjected to, on the specific resource block.
[0102] 6. The wireless communication device according to embodiment
5, wherein the calculation unit is further configured to calculate
a sum of inter-cell SINRs of the target cell with respect to all of
the other cells in the cell cluster on the specific resource
block.
[0103] 7. The wireless communication device according to embodiment
6, wherein the control unit is configured to performed the control
to determine whether the sum of the inter-cell SINRs is less than 1
if the overall channel quality is classified as good, and determine
the target transmission power by decreasing, by a certain step
length, transmission power of the target cell on the specific
resource block if it is determined that the sum of the inter-cell
SINRs is not less than 1.
[0104] 8. The wireless communication device according to embodiment
6 or 7, wherein the control unit is configured to perform a control
to determine whether the sum of the inter-cell SINRs is less than 1
if the overall channel quality is classified as good; and determine
the target transmission power of the target cell on the specific
resource block by making a first-order partial derivative of a
total throughput of all cells in the cell cluster on the specific
resource block with respect to the transmission power of the target
cell on the specific resource block equal to 0 if it is determined
that the sum of the inter-cell SINRs is less than 1.
[0105] 9. The wireless communication device according to any one of
embodiments 2-8, wherein the control unit is configured to perform
a control to determine the target transmission power of the target
cell on the specific resource block by making a first-order partial
derivative of a total throughput of all cells in the cell cluster
on the specific resource block with respect to the transmission
power of the target cell on the specific resource block equal to 0
if the overall channel quality is classified as bad.
[0106] 10. The wireless communication device according to any one
of embodiments 2-9, wherein the calculation unit is further
configured to compare values of first-order and second-order
partial derivatives of a total throughput of all cells in the cell
cluster on the specific resource block with respect to the
transmission power of the target cell on the specific resource
block with zero; and
[0107] the control unit is configured to perform a control to
determine the target transmission power of the target cell on the
specific resource block by making the first-order partial
derivative equal to 0, in a case that the overall channel quality
is classified as normal and it is determined by the calculation
unit via the comparison that the value of the first-order partial
derivative is greater than 0 and the value of the second-order
partial derivative is less than 0.
[0108] 11. The wireless communication device according to
embodiment 10, wherein the control unit is configured to perform a
control to determine the target transmission power of the target
cell on the specific resource block by decreasing, by a certain
step length, the transmission power of the target cell on the
specific resource block, in a case that the overall channel quality
is classified as normal and it is determined by the calculation
unit via the comparison that the value of the first-order partial
derivative is less than 0.
[0109] 12. The wireless communication device according to any one
of embodiments 8-11, wherein the first-order partial derivative is
represented as
.differential. R k .differential. p i k , ##EQU00036##
wherein
R k = i = 1 N log 2 ( 1 + p i k g i , i k j .noteq. i , j = 1 N p j
k g j , i k + .sigma. 2 ) ##EQU00037##
represents th total throughput of all the cells in the cell cluster
on the specific resource block k, p.sub.i.sup.k represents the
transmission power of a cell CS.sub.i on the resource block k,
g.sub.i,j.sup.k represents a channel gain from a cell CS.sub.j to a
user equipment in the cell CS.sub.i occupying the resource block k,
.sigma..sup.2 represents power of white Gaussian noise.
[0110] 13. A wireless communication method, including:
[0111] classifying an overall channel quality based on channel
qualities of downlinks of a target cell and other cells in a cell
cluster on a specific resource block; and
[0112] perform a control to determine a target transmission power
of the target cell on the specific resource block by a power
allocating method adaptive to a classification of the overall
condition.
[0113] 14. The wireless communication method according to
embodiment 13, wherein according to a predetermined classification
criterion, the classification of the overall channel quality
includes: good, normal, and bad.
[0114] 15. The wireless communication method according to
embodiment 14, wherein each of the channel qualities is
characterized by a SINR.
[0115] 16. The wireless communication method according to
embodiment 15, wherein the predetermined classification criterion
includes:
[0116] the overall channel quality is classified as good if SINRs
of the target cell and the other cells are all much greater than
1;
[0117] the overall channel quality is classified as bad if SINRs of
the target cell and the other cells are all much less than 1;
and
[0118] the overall channel quality is classified as normal in other
cases.
[0119] 17. The wireless communication method according to any one
of embodiments 13-16, further including: calculating an inter-cell
SINR of the target cell with respect to a first other cell on the
specific resource block, wherein the inter-cell SINR is defined as:
a ratio of the interference on the first other cell from the target
cell versus a sum of all interference and noise the first other
cell is subjected to, on the specific resource block.
[0120] 18. The wireless communication method according to
embodiment 17, further including: calculating a sum of inter-cell
SINRs of the target cell with respect to all of other cells in the
cell cluster on the specific resource block.
[0121] 19. The wireless communication method according to
embodiment 18, wherein the controlling includes: determining
whether the sum of the inter-cell SINRs is less than 1 in a case
that the overall channel quality is classified as good; and
determining the target transmission power by decreasing, by a
certain step length, transmission power of the target cell on the
specific resource block, if it is determined that the sum of the
inter-cell SINRs is not less than 1.
[0122] 20. The wireless communication method according to
embodiment 18 or 19, wherein the controlling includes: determining
whether the sum of the inter-cell SINRs is less than 1 in a case
that the overall channel quality is classified as good; and
determining the target transmission power of the target cell on the
specific resource block by making a first-order partial derivative
of a total throughput of all cells in the cell cluster on the
specific resource block with respect to the transmission power of
the target cell on the specific resource block equal to 0, if it is
determined that the sum of the inter-cell SINRs is less than 1.
[0123] 21. The wireless communication method according to any one
of embodiments 14-20, wherein the controlling includes: determining
the target transmission power of the target cell on the specific
resource block by making a first-order partial derivative of a
total throughput of all cells in the cell cluster on the specific
resource block with respect to transmission power of the target
cell on the specific resource block equal to 0, in a case that the
overall channel quality is classified as bad.
[0124] 22. The wireless communication method according to any one
of embodiments 14-21, further including: comparing values of
first-order and second-order partial derivatives of a total
throughput of all cells in the cell cluster on the specific
resource block with respect to transmission power of the target
cell on the specific resource block with 0; and
[0125] the controlling includes: determining the target
transmission power of the target cell on the specific resource
block by making the first-order partial derivative equal to 0, in a
case that the overall channel quality is classified as normal and
it is determined via the comparison that the value of the
first-order partial derivative is greater than 0 and the value of
the second-order partial derivative is less than 0.
[0126] 23. The wireless communication method according to
embodiment 22, wherein the controlling includes: determining the
target transmission power of the target cell on the specific
resource block by decreasing, by a certain step length, the
transmission power of the target cell on the specific resource
block, in a case that the overall channel quality is classified as
normal and it is determined by the comparison that the value of the
first-order partial derivative is less than 0.
[0127] 24. The wireless communication method according to any one
of embodiments 20-23, wherein the first-order partial derivative is
represented as
.differential. R k .differential. p i k , ##EQU00038##
wherein
R k = i = 1 N log 2 ( 1 + p i k g i , i k j .noteq. i , j = 1 N p j
k g j , i k + .sigma. 2 ) ##EQU00039##
represents the total throughput of all the cells in the cell
cluster on a specific resource block k, p.sub.i.sup.k represents
the transmission power of a cell CS.sub.i on the resource block k,
g.sub.i,j.sup.k represents a channel gain from a cell CS.sub.j to a
user equipment in the cell CS.sub.i occupying the resource block k,
and .sigma..sup.2 presents power of white Gaussian noise.
[0128] 25. A wireless communication device, including:
[0129] a classification unit, configured to classify a user
equipment in a cell cluster based on average channel quality of
downlinks to the user equipment in a predetermined time period;
[0130] an allocating unit, configured to allocate a resource block
set to the user equipment at least partly based on the
classification of the user equipment, wherein the allocating unit
allocates a same resource block set to user equipments of the same
classification; and
[0131] a control unit, configured to perform a control to determine
a target transmission power of a target cell on a specific resource
block by a power allocating method adaptive to a classification of
the user equipment scheduled by the target cell on the specific
resource block.
[0132] 26. The wireless communication device according to
embodiment 25, wherein the average channel quality is characterized
by an average SINR of the user equipment in the predetermined time
period.
[0133] 27. The wireless communication device according to
embodiment 26, wherein the classification unit is configured to:
classify the user equipment into a first type if the average SINR
is much greater than 1;
[0134] classify the user equipment into a second type if the
average SINR is much less than 1; and
[0135] classify the user equipment into a third type if the average
SINR is neither much greater than 1 nor much less than 1.
[0136] 28. The wireless communication device according to any one
of embodiments 25 to 27, wherein the allocating unit allocates the
resource block set to the user equipment at least partly based on
the numbers of user equipments of different types.
[0137] 29. The wireless communication device according to
embodiment 28, wherein the allocating unit allocates the resource
block set at least partly based on service requirements of the user
equipments of different classifications.
[0138] 30. The wireless communication device according to
embodiment 29, further including: a calculation unit, wherein the
calculation unit is configured to calculate an inter-cell SINR of
the target cell with respect to a first non-target cell on the
specific resource block, wherein the inter-cell SINR is defined as:
a ratio of the interference on the first non-target cell from the
target cell versus a sum of all interference and noise the first
non-target cell is subjected to, on the specific resource
block.
[0139] 31. The wireless communication device according to
embodiment 30, wherein the calculation unit is further configured
to calculate a sum of inter-cell SINRs of the target cell with
respect to all non-target cells in the cell cluster.
[0140] 32. The wireless communication device according to
embodiment 31, wherein the control unit is configured to: determine
whether the sum of the inter-cell SINRs is less than 1 in a case
that the user equipment is classified into the first type; and
determine the target transmission power of the target cell on the
specific resource block by making a first-order partial derivative
of a total throughput of all cells in the cell cluster on the
specific resource block with respect to transmission power of the
target cell on the specific resource block equal to 0, if it is
determined that the sum of the inter-cell SINRs is less than 1.
[0141] 33. The wireless communication device according to
embodiment 31 or 32, wherein the control unit is configured to:
determine whether the sum of the inter-cell 1 SINRs is less than 1
in a case that the user equipment is classified into the first
type; and determine the target transmission power by decreasing, by
a certain step length, transmission power of the target cell on the
specific resource block, if the sum of the inter-cell signal to
interference plus noise is not less than 1.
[0142] 34. The wireless communication device according to any one
of embodiments 27 to 33, wherein the control unit is configured to:
determine the target transmission power of the target cell on the
specific resource block by making a first-order partial derivative
of a total throughput of all cells in the cell cluster on the
specific resource block with respect to the transmission power of
the target cell on the specific resource block equal to 0, if the
user equipment is classified into the second type.
[0143] 35. The wireless communication device according to any one
of embodiments 27 to 34, wherein the calculation unit is further
configured to compare values of first-order and second-order
partial derivatives of a total throughput of all cells in the cell
cluster on the specific resource block with respect to the
transmission power of the target cell on the specific resource
block with 0; and
[0144] the control unit is configured to determine the target
transmission power of the target cell on the specific resource
block by making the first-order partial derivative equal to 0, in a
case that the user equipment is classified into the third type and
it is determined by the calculation unit via the comparison that
the value of the first-order partial derivative is greater than 0
and the value of the second-order partial derivative is less than
0.
[0145] 36. The wireless communication device according to
embodiment 35, wherein the control unit is configured to determine
the target transmission power of the target cell on the specific
resource block by decreasing, by a certain step length, the
transmission power of the target cell on the specific resource
block, in a case that the user equipment is classified into the
third type and it is determined by the calculation unit via the
comparison that the value of the first-order partial derivative is
less than 0.
[0146] 37. A wireless communication method, including:
[0147] classifying a user equipment in a cell cluster based on
average channel quality of downlinks to the user equipment in a
predetermined time period;
[0148] allocating a resource block set to the user equipment at
least partly based on a classification of the user equipment,
wherein a same resource block set is allocated to user equipments
of the same classification; and
[0149] performing a control to determine a target transmission
power of a target cell on a specific resource block by a power
allocating method adaptive to a classification of the user
equipment scheduled by the target cell on the specific resource
block.
[0150] 38. The wireless communication method according to
embodiment 37, wherein the average channel quality is characterized
by an average SINR of the user equipment in the predetermined time
period.
[0151] 39. The wireless communication method according to
embodiment 38, wherein the classifying includes:
[0152] classifying the user equipment into a first type if the
average SINR is much greater than 1;
[0153] classifying the user equipment into a second type if the
average SINR is much less than 1; and
[0154] classifying the user equipment into a third type if the
average SINR is neither much greater than 1 nor much less than
1.
[0155] 40. The wireless communication method according to any one
of embodiments 37 to 39, wherein the resource block set is
allocated to the user equipment at least partly based on the
numbers of user equipments of different types.
[0156] 41. The wireless communication method according to
embodiment 40, wherein the resource block set is allocated at least
partly based on service requirements of the user equipments of
different types.
[0157] 42. The wireless communication method according to
embodiment 41, further including: calculating an inter-cell SINR of
the target cell with respect to a first non-target cell on the
specific resource block, wherein the inter-cell SINR is defined as:
a ratio of the interference on the first non-target cell from the
target cell versus a sum of all interference and noise the first
non-target cell is subjected to, on the specific resource
block.
[0158] 43. The wireless communication method according to
embodiment 42, further including: calculating a sum of inter-cell
SINRs of the target cell with respect to all of non-target cells in
the cell cluster.
[0159] 44. The wireless communication method according to
embodiment 43, wherein the controlling includes: determining
whether the sum of the inter-cell SINRs is less than 1 in a case
that the user equipment is classified into the first type; and
determining the target transmission power of the target cell on the
specific resource block by making a first-order partial derivative
of a total throughput of all cells in the cell cluster on the
specific resource block with respect to transmission power of the
target cell on the specific resource block equal to 0, if it is
determined that the sum of the inter-cell SINRs is less than 1.
[0160] 45. The wireless communication method according to
embodiment 43 or 44, wherein the controlling includes: determining
whether the sum of the inter-cell SINRs is less than 1 in a case
that the user equipment is classified into the first type; and
determining the target transmission power by decreasing, by a
certain step length, transmission power of the target cell on the
specific resource block, if it is determined that the sum of the
inter-cell signal to interference plus noise is not less than
1.
[0161] 46. The wireless communication method according to any one
of embodiments 39 to 45, wherein the controlling includes:
determining the target transmission power of the target cell on the
specific resource block by making a first-order partial derivative
of a total throughput of all cells in the cell cluster on the
specific resource block with respect to transmission power of the
target cell on the specific resource block equal to 0, if the user
equipment is classified into the second type.
[0162] 47. The wireless communication method according to any one
of embodiments 39 to 46, further including: comparing values of
first-order and second-order partial derivatives of a total
throughput of all cells in the cell cluster on the specific
resource block with respect to transmission power of the target
cell on the specific resource block with 0; and
[0163] the controlling includes: determining the target
transmission power of the target cell on the specific resource
block by making the first-order partial derivative equal to 0, in a
case that the user equipment is classified into the third type and
it is determined via the comparison that the value of the
first-order partial derivative is greater than 0 and the value of
the second-order partial derivative is less than 0.
[0164] 48. The wireless communication method according to
embodiment 47, wherein the controlling includes: determining the
target transmission power of the target cell on the specific
resource block by decreasing, by a certain step length,
transmission power of the target cell on the specific resource
block, in a case that the user equipment is classified into the
third type and it is determined via the comparison that the value
of the first-order partial derivative is less than 0.
[0165] 49. A wireless communication system, including the wireless
communication device according to any one of embodiments 1-12 and
embodiments 25-36.
[0166] 50. The wireless communication system according to
embodiment 49, wherein the wireless communication device is
arranged in a base station of the wireless communication system, or
is arranged separately from the base station.
[0167] 51. The wireless communication system according to
embodiment 50, wherein a user equipment in the wireless
communication system measures and provides received power received
by the user equipment from all cells other than a serving cell of
the user equipment.
* * * * *