CN102223342A - Downlink multi-input single-output-OFDMA (Orthogonal Frequency Division Multiplex Access) multicast system resource allocation method - Google Patents

Downlink multi-input single-output-OFDMA (Orthogonal Frequency Division Multiplex Access) multicast system resource allocation method Download PDF

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CN102223342A
CN102223342A CN2011101737153A CN201110173715A CN102223342A CN 102223342 A CN102223342 A CN 102223342A CN 2011101737153 A CN2011101737153 A CN 2011101737153A CN 201110173715 A CN201110173715 A CN 201110173715A CN 102223342 A CN102223342 A CN 102223342A
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user
group
subcarrier
candidate set
wave beam
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CN102223342B (en
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季飞
邓校成
江兴祥
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South China University of Technology SCUT
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South China University of Technology SCUT
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Abstract

The invention relates to a downlink multi-input single-output-OFDMA (Orthogonal Frequency Division Multiplex Access) multicast system resource allocation method which comprises the following steps that in an OFDMA multicast system, a plurality of antennas are arranged at base station equipment, a single antenna is arranged at user terminal equipment, a base station allocates subcarriers for user groups according to channel conditions of the user groups, simultaneously determines transmitting terminal precodings corresponding to the subcarriers for different user groups; through power water injection, power is allocated for the subcarriers allocated to the user groups; the subcarriers and the power allocation are subject to reasonable adjustment to meet the user groups which are not met in data rate requirements. By adopting the method disclosed by the invention, the higher data rate and higher user fairness can be realized, and simultaneously, the lower complexity of the downlink multi-input single-output-OFDMA multicast system resource allocation can be maintained.

Description

A kind ofly descendingly go into singly to go out-OFDM multicast system resource allocation methods more
Technical field
The present invention relates to many transmitting antennas be arranged and the user has only the resource allocation of the descending multicast system of a transmitting antenna, particularly a kind of descendingly go into singly to go out-OFDM multicast system resource allocation methods more in the base station.
Background technology
Multiple Input Multiple Output (hereinafter to be referred as the MIMO technology) can significantly improve the power system capacity of wireless system by spatial reuse.In the mimo system, it is the parallel channel of feature that the mutual independent user of each channel is existed with mutually orthogonal spatial signature vectors (SSV), can transmission simultaneously under the situation that does not have cochannel interference (CCI) through the data of spatial signature vectors precoding.If the space vector of different user is a mutually orthogonal, Chuan Shu user data can be multiplexed in the spatial domain simultaneously.In order to improve the link performance of mimo system, need utilize the knowledge of mimo channel and carry out precoding at transmitting terminal.As a kind of special circumstances of MIMO, in the MISO system, receiving terminal has only a reception antenna, so can only carry out precoding at transmitting terminal.
Orthogonal frequency division multiplexi (OFDM) is a kind of multi-carrier communication mode, main thought is by broad-band channel being divided into the subchannel (subcarrier) of a lot of bandwidth much smaller than the correlated bandwidth of channel, high-speed data-flow is divided into the data flow of a plurality of low speed and is modulated to respectively in the independent subcarrier.Channel distribution reduces the selectivity of channel frequency decline, and data flow is divided the intersymbol interval that has increased data flow in each carrier wave, has reduced intersymbol interference.
Go into singly (MISO) system also can dispatch the user on the spatial domain by the many antennas on the base station more; OFDM (OFDMA) system allows on time-frequency domain the user to be carried out data dispatch.Recycling OFDM OFDMA running time-frequency resource means a plurality of data flow of transmission on the same time-frequency on the spatial domain.For the cochannel of eliminating different pieces of information on the same time-frequency fully disturbs, the space vector of different user must be a mutually orthogonal.Therefore, OFDMA provides the time frequency grid of orthogonal channel between different user, and the MIMO technology is further divided the channel that available channel produces mutually orthogonal in the spatial domain.
In the wireless multicast system, the user is divided into a plurality of user's groups, and the usefulness of each user's group receives identical data per family.Have only unique user when every group, system is converted into unicast system; And but have only a group or all in the system with belonging to same user's group per family, then system is converted into broadcast system.The same with unicast system, the mechanism of distinguishing different pieces of information must be arranged in the multicast system; Similar with broadcast system, multicast system must guarantee that all users of every group can both reach this and organize desired data rate.Therefore, the resource allocation methods of existing clean culture and broadcast system all can not be applied in the multicast system.
Summary of the invention
For overcoming the deficiency of existing correlation technique, main purpose of the present invention is to provide a kind of and descending goes into singly to go out-OFDM multicast system resource allocation methods more, be to go into singly (MISO) multicast system in descending OFDM (OFDMA) more, it is a kind of resource allocation methods in the descending MISO-OFDMA multicast system in frequency domain and spatial domain, this method can realize higher data speed and higher user fairness, reduces simultaneously descendingly to go into singly to go out-complexity of OFDM multicast system resource allocation more.
Purpose of the present invention is achieved by following technical proposals:
1), the power that presets all subcarriers estimates initial value, putting subcarrier, just to distribute iterations be 1, is limited to 4 on the iteration, beginning first run subcarrier just distributes iteration;
Described power estimates that the formula that presets of initial value is:
If sub-carrier number is
Figure 517505DEST_PATH_IMAGE001
, each subcarrier on average by
Figure 234926DEST_PATH_IMAGE002
Individual user organizes shared, and system's gross power is
Figure 630135DEST_PATH_IMAGE003
, the power that then presets estimates that initial value is
Figure 382190DEST_PATH_IMAGE004
,
Figure 142336DEST_PATH_IMAGE005
2), each user's group has its data rate requirement in the system, all users form users and organize candidate collection;
3), for any one current subcarrier that is not assigned with, each user of each user group has corresponding channel fading coefficient in the system, with the group channel fading coefficient of channel fading coefficient minimum in each user's group as this user's group; The user is organized the group channel fading coefficient of each user's group in the candidate collection and do descending; With user's group is that unit divides group channel fading coefficient behind the descending to form an above wave beam candidate set;
4), from the wave beam candidate set that produces, select a wave beam candidate set that comprises minimum inactive users; Described inactive users be come from different user groups but have the different user of the channel matrix of linear correlation, if the wave beam candidate set only comprises a group, then do not have inactive users;
5), if the wave beam candidate set selected only comprises user's group, then this user organizes the current subcarrier that acquisition is not assigned with; Start transmitting terminal precoding algorithm then, ask for the transmitting terminal precoding of the unique user's group that has obtained current subcarrier;
6), if the velocity of wave candidate set of selecting comprises a plurality of user's groups, then the user group that comprises of this wave beam candidate set all obtains current subcarrier, then each user's channel matrix in each the user's group that has obtained current subcarrier is made BD and decompose, organize corresponding transmitting terminal precoding to ask for these users;
7), for the user group that has obtained current subcarrier, calculate the data rate that this subcarrier provides with the shannon formula of correction; The current data rate that all subcarriers provided of having distributed to this user group that adds up obtains the current data speed of this user's group; Judge whether current data speed satisfies the data rate requirement of this user group,, this user's group organized the candidate collection from the user remove name from the rolls if satisfy; If do not satisfy, this user's group still is retained in the user and organizes in the candidate collection; Repeating step 3) to step 7), all subcarriers all obtain distributing in system, and execution in step 8 again);
8), statistical system subcarrier allocation situation, calculate sub-carrier power thus and estimate final value; Judge current subcarrier just distributes iterations whether to equal its upper limit; If equal, then execution in step 9); Otherwise, all sub-carrier power estimate that initial value is updated to the average that former sub-carrier power is estimated initial value and sub-carrier power estimation final value, and make subcarrier just distribute iterations to increase 1, return execution in step 2 then), estimate that with new sub-carrier power initial value carries out distributing iteration at the beginning of next wheel carries;
Described sub-carrier power estimates that the calculating formula of final value is:
The system gross power of setting up departments is , the user organizes number and is in the system
Figure 483635DEST_PATH_IMAGE006
, the The sub-carrier number that individual user organizes acquisition is
Figure 83561DEST_PATH_IMAGE008
, then the subcarrier allocation number of system after multiplexing is
Figure 778503DEST_PATH_IMAGE009
, sub-carrier power estimates that final value is
Figure 718777DEST_PATH_IMAGE010
Like this, step 2) form complete one to step 8) and take turns iteration, so through after 4 iteration, subcarrier just distributes iterations will finally arrive the upper limit, and no longer carry out subcarrier and just distribute iteration and turn to step 9) this moment;
9), the base station gross power is assigned on the subcarrier of each user's group with water-filling algorithm; According to the power division situation, calculate the actual data rate of each user's group, and check whether actual data rate satisfies the data rate requirement of each user's group; If all satisfy, then resource allocation process finishes; Otherwise, execution in step 10);
10), resource allocation adjustment: check whether user's group that data rate requires to be met has the subcarrier of monopolizing; If user group has the subcarrier of monopolizing, and remove that the data rate of this user's group requires still to be met behind this subcarrier, then extract this subcarrier; So all data rates of traversal require each user who is met to organize, and the subcarrier that extracts is heavily distributed to data rate require the user who is not met to organize, and heavily distribute to finish subcarrier; Again carry out the power water filling then, system resource allocation finishes.
The invention provides the method for an above wave beam candidate set of the described formation of a kind of step 3), concrete steps are:
, wave beam candidate set of definition, will organize the channel fading coefficient and do descending, and the user who ranks first in the descending organized add this wave beam candidate set, this user is organized from descending, remove name from the rolls then; At this moment, if the number of users that comprises of this wave beam candidate set is greater than number of transmit antennas, then the current unique user who comprises of this wave beam candidate set organizes and has constituted this wave beam candidate set, step 3) leave it at that, and only formed a wave beam candidate set; If the customer volume of this wave beam candidate set smaller or equal to number of transmit antennas, is carried out
Figure 219477DEST_PATH_IMAGE012
And step
Figure 461103DEST_PATH_IMAGE013
, the wave beam candidate set customer volume during smaller or equal to number of transmit antennas, seek user's group the residue descending after removing name from the rolls through user's group, make that adding this user organizes the customer volume of back wave beam candidate set still smaller or equal to number of transmit antennas; If find, then this user's group is also added in the wave beam candidate set, again this user's group is removed name from the rolls from the residue descending; If can not find, the current user who comprises of wave beam candidate set organizes and has constituted this wave beam candidate set, defines a new wave beam candidate set then;
Figure 317380DEST_PATH_IMAGE013
, repeating step
Figure 855809DEST_PATH_IMAGE012
Up to the descending of group channel coefficients is empty, produces more than one wave beam candidate set thus.
The invention provides the described transmitting terminal precoding of a kind of step 5) algorithm, be specially:
If user's group has
Figure 256834DEST_PATH_IMAGE014
Individual user , each user is corresponding to the channel matrix and the channel fading coefficient difference of current subcarrier With
Figure 540027DEST_PATH_IMAGE017
(
Figure 428348DEST_PATH_IMAGE018
), wherein
Figure 310853DEST_PATH_IMAGE019
For
Figure 601021DEST_PATH_IMAGE020
The dimension matrix, and
Figure 543569DEST_PATH_IMAGE021
,
Figure 919186DEST_PATH_IMAGE022
Be the matrix norm computing; If the optimum precoding of transmitting terminal is
Figure 543066DEST_PATH_IMAGE023
(
Figure 750056DEST_PATH_IMAGE024
), then for other arbitrary transmitting terminal precodings
Figure 801189DEST_PATH_IMAGE025
(
Figure 726420DEST_PATH_IMAGE026
) and arbitrarily
Figure 888411DEST_PATH_IMAGE018
All satisfy:
Figure 215487DEST_PATH_IMAGE027
Wherein,
Figure 171941DEST_PATH_IMAGE028
Be the computing of Matrix Conjugate transposition,
Figure 584468DEST_PATH_IMAGE029
In scope
Figure 564799DEST_PATH_IMAGE018
In get the expression formula minimum operation; Produce several transmitting terminal precodings at random
Figure 746381DEST_PATH_IMAGE025
, therefrom find out the transmitting terminal precoding that to satisfy following formula , be of the transmitting terminal precoding of this user's group corresponding to current subcarrier.
Sub-carrier power estimation initial value value during the described subcarrier of step 10) heavily distributes is taken turns subcarrier for last and is just distributed the sub-carrier power of iteration gained to estimate initial value; In the heavy assigning process, subcarrier is directly distributed to user's group that first wave beam candidate set comprises, and does not reexamine the inactive users of wave beam candidate set.
Compared with prior art, the present invention has the following advantages:
(1) the present invention serves as according to the distribution of determining this subcarrier with the subscriber channel coefficient of the different user groups of subcarrier correspondence and the inactive users amount that does not comprise on the same group, has well utilized the multi-user diversity of system;
(2) the present invention estimates initial value by adjusting sub-carrier power, makes power estimation and user organize speed and estimates that realistic preferably sub-carrier power is distributed and the user organizes speed;
(3) the present invention is by determining corresponding not on the same group transmitting terminal precoding, and the cochannel of having eliminated between a plurality of data flow on the same subcarrier disturbs, and has reduced computation complexity simultaneously;
(4) data rate that has guaranteed each user's group that heavily distributes of resource of the present invention requires and can be met, thereby has obtained the fairness between user's group.
Description of drawings
Fig. 1 goes into singly to go out for the present invention is descending more-machine that the transmits and receives structure of OFDM multicast system;
Fig. 2 goes into singly to go out for the present invention is descending more-the wireless resource allocation methods flow chart of OFDM multicast system;
Fig. 3 is the algorithm flow chart that subcarrier of the present invention just distributes;
Fig. 4 is the algorithm flow chart of resource re-allocation of the present invention.
Embodiment
The present invention is described further below in conjunction with the drawings and specific embodiments, but be not limited thereto.
One of embodiment of the invention is the resource allocation of the down link MISO-OFDMA multicast system from the base station to user.
Certain sending/receiving type constantly is as follows on certain subcarrier of MISO-OFDMA multicast system:
Figure 773560DEST_PATH_IMAGE030
Formula (1)
Figure 277354DEST_PATH_IMAGE031
Wherein
Figure 579022DEST_PATH_IMAGE032
Be user in user's group
Figure 142859DEST_PATH_IMAGE033
The received signal in a certain moment,
Figure 264398DEST_PATH_IMAGE034
Be the channel fading coefficient of this user corresponding to this subcarrier,
Figure 571883DEST_PATH_IMAGE035
(
Figure 728058DEST_PATH_IMAGE036
, promptly For
Figure 71631DEST_PATH_IMAGE037
The dimension matrix,
Figure 917228DEST_PATH_IMAGE038
Be number of transmit antennas) be the user Channel matrix,
Figure 833548DEST_PATH_IMAGE039
Be user's group
Figure 929680DEST_PATH_IMAGE040
Power division on subcarrier,
Figure 576038DEST_PATH_IMAGE041
Be user's group
Figure 441225DEST_PATH_IMAGE040
Corresponding transmitting terminal precoding,
Figure 517766DEST_PATH_IMAGE042
(
Figure 38877DEST_PATH_IMAGE043
) for sending to user's group
Figure 554172DEST_PATH_IMAGE040
All users' information,
Figure 211549DEST_PATH_IMAGE044
Be the user
Figure 521308DEST_PATH_IMAGE033
The white Gaussian noise that receives.
The base station receives the channel information of each user group, be user's set of dispense subcarrier according to the channel conditions of user and relative users group thereof, and determines the transmitting terminal precoding of each group correspondence.
For the subcarrier of monopolizing by the unique user group, by produce a series of random vectors and find out in the middle of the superior's method obtain the transmitting terminal precoding, detailed process is as follows:
If this user's group has
Figure 529715DEST_PATH_IMAGE014
Individual user
Figure 583122DEST_PATH_IMAGE045
, the channel matrix of corresponding subcarrier is respectively
Figure 360585DEST_PATH_IMAGE046
, wherein
Figure 841245DEST_PATH_IMAGE047
(
Figure 336948DEST_PATH_IMAGE018
) be
Figure 928467DEST_PATH_IMAGE048
Dimension matrix (channel vector), and ,
Figure 477577DEST_PATH_IMAGE050
Be the matrix norm computing; Corresponding channel fading coefficient is
Figure 197927DEST_PATH_IMAGE051
If the optimum precoding of transmitting terminal is (
Figure 345191DEST_PATH_IMAGE048
The dimension matrix), then for other arbitrary transmitting terminal precodings
Figure 167654DEST_PATH_IMAGE025
(
Figure 372370DEST_PATH_IMAGE026
) and arbitrarily
Figure 571270DEST_PATH_IMAGE018
All satisfy:
Figure 177832DEST_PATH_IMAGE052
Formula (2)
Wherein,
Figure 171196DEST_PATH_IMAGE053
Be the computing of Matrix Conjugate transposition,
Figure 863209DEST_PATH_IMAGE054
For getting the minimum operation in the prescribed limit.
Organize shared subcarrier for a plurality of users,, need that then the channel matrix of a plurality of user's groups is made BD and decompose, to obtain the transmitting terminal precoding for the cochannel of eliminating on the same subcarrier disturbs.
BD decomposes reference literature (Quentin H. Spencer, A. Lee Swindlehurst, and Martin Haardt, Zero-forcing methods for downlink spatial multiplexing in multiuser MIMO channels, IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 52, NO. 2, and FEBRUARY 2004.
Lai-U Choi and Ross D. Murch, A Transmit Preprocessing Technique for Multiuser MIMO Systems Using a Decomposition Approach, IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 3, NO. 1, JANUARY 2004.), concrete decomposable process is as follows:
Be provided with
Figure 600220DEST_PATH_IMAGE006
Individual user's group (is respectively that the user organizes ) share same subcarrier, the number of users of each user's group is respectively
Figure 428816DEST_PATH_IMAGE056
, have
Figure 670442DEST_PATH_IMAGE057
If the
Figure 883248DEST_PATH_IMAGE058
Group the
Figure 526719DEST_PATH_IMAGE059
Individual user's channel matrix is respectively
Figure 796639DEST_PATH_IMAGE060
( ), then this
Figure 542058DEST_PATH_IMAGE006
The channel matrix that individual user organizes all users constitutes matrix, for:
Figure 40036DEST_PATH_IMAGE062
?（ ）
In order to obtain
Figure 637687DEST_PATH_IMAGE058
Individual user organizes corresponding transmitting terminal precoding, from matrix
Figure 520193DEST_PATH_IMAGE064
In extract the out
Figure 810360DEST_PATH_IMAGE058
After organizing the channel vector of each user's correspondence, again the channel vector of all the other user's groups is formed new matrix, carry out matrix transpose then, obtain Formula (3)
Wherein
Figure 128526DEST_PATH_IMAGE066
For the matrix transpose computing, right
Figure 549143DEST_PATH_IMAGE067
Make SVD and decompose:
Figure 959395DEST_PATH_IMAGE068
Formula (4)
Obtain
Figure 72845DEST_PATH_IMAGE069
The transmitting terminal precoding that group is corresponding
Figure 935759DEST_PATH_IMAGE070
, in like manner can arrive its user and organize corresponding transmitting terminal precoding.
For the user's group that has obtained subcarrier, calculate the data rate that this subcarrier provides with the shannon formula of revising; The current data rate that all subcarriers provided of having distributed to this user group that adds up obtains the current data speed of this user's group.(the reference literature Goldsmith A J of system for the M-QAM modulation system, Chua S. Variable-rate variable-power MQAM for fading channels. IEEE Transactions on Communications.1997.45 (10): 1218-1230), calculate user's group by following formula
Figure 160067DEST_PATH_IMAGE040
Present rate:
Figure 150458DEST_PATH_IMAGE071
Formula (5)
Figure 434808DEST_PATH_IMAGE072
Wherein
Figure 785018DEST_PATH_IMAGE073
, Be respectively and obtain the forward and backward data rate of subcarrier,
Figure 932283DEST_PATH_IMAGE075
For the power of subcarrier is estimated initial value,
Figure 121956DEST_PATH_IMAGE076
Be the bandwidth of subcarrier,
Figure 959462DEST_PATH_IMAGE077
,
Figure 525572DEST_PATH_IMAGE078
Be respectively
Figure 764924DEST_PATH_IMAGE040
The user's that the group channel conditions is the poorest channel coefficients (
Figure 125498DEST_PATH_IMAGE040
The group channel coefficients of group) and channel matrix,
Figure 450300DEST_PATH_IMAGE079
Be transmitting terminal precoding to organizing,
Figure 820101DEST_PATH_IMAGE080
The variance of white Gaussian noise,
Figure 648380DEST_PATH_IMAGE081
Be error rate requirement.
Step of the present invention as shown in Figure 2, after the grouping information and channel information of base station by all users in the dedicated channel acquisition system, this resource allocation algorithm is from following steps:
Step 1: carry out subcarrier and just distribute iteration, and determine respectively to organize the transmitting terminal precoding of corresponding different sub carrier;
Step 2: distribute power by the respective sub that the power water filling is distributed for each group;
Step 3: the data rate that judges whether all user's groups requires all to be met, if algorithm finishes, otherwise, execution in step 4;
Step 4: implement resource re-allocation, algorithm finishes.
The described subcarrier of step 1 just distributes iterative process figure as shown in Figure 3:
(1): initialization first round subcarrier just distributes iteration: preset sub-carrier power and estimate initial value; It is 1 that the initialization subcarrier just distributes iterations, and sets and be limited to 4 on it.The system sub-carrier number of setting up departments is
Figure 445435DEST_PATH_IMAGE001
, on average each subcarrier by
Figure 991954DEST_PATH_IMAGE002
Individual group share (
Figure 165446DEST_PATH_IMAGE005
,
Figure 110881DEST_PATH_IMAGE002
But value 2), system's gross power is , then can preset sub-carrier power and estimate that initial value is
Figure 174969DEST_PATH_IMAGE004
Figure 824256DEST_PATH_IMAGE002
Size only influence the convergence rate that sub-carrier power is estimated initial value, do not influence its convergence;
(2): all users of system organize the formation user and organize candidate collection, and first subcarrier of pointing system;
(3): the user is organized each user group in the candidate collection, select the user of the channel fading coefficient minimum of current subcarrier correspondence, and with the group channel coefficients of its channel coefficients as this group; The group channel coefficients will be used for calculating the current data speed of user's group in subsequent step;
(4): arrange each user's group that the user organizes candidate collection by the descending of group channel fading coefficient;
(5): divide above-mentioned arrangement to form an above wave beam candidate set, partition process is as follows:
Figure 689444DEST_PATH_IMAGE011
Organize the group channel coefficients that interior minimum subscriber channel coefficient is organized as this user with the user; Arrange user's group by the descending of group channel coefficients;
Define a wave beam candidate set, and the user who ranks first in the descending is organized adding wave beam candidate set, this user's group is removed name from the rolls from arrange then; At this moment, if the customer volume of wave beam candidate set greater than number of transmit antennas
Figure 349413DEST_PATH_IMAGE038
, the current unique user who comprises of wave beam candidate set organizes and has constituted this wave beam candidate set, and step (5) leaves it at that; Otherwise, carry out
Figure 536811DEST_PATH_IMAGE013
With
Figure 522085DEST_PATH_IMAGE082
The customer volume of wave beam candidate set smaller or equal to
Figure 840251DEST_PATH_IMAGE038
The time, in arrangement, seek a group, make add this group back wave beam candidate set customer volume still smaller or equal to
Figure 831341DEST_PATH_IMAGE038
If find, then this group also adds in the wave beam candidate set, and this group is removed name from the rolls from arrange; If can not find, the current user who comprises of wave beam candidate set organizes and has constituted this wave beam candidate set, defines a new wave beam candidate set then;
Repeat
Figure 89464DEST_PATH_IMAGE013
Up to the descending of group channel coefficients is empty, produces a plurality of wave beam candidate set thus.
(6): subcarrier allocation: if only formed a wave beam candidate set in the step (5), then the group that comprises of this wave beam candidate set obtains current subcarrier; If formed a plurality of velocity of wave candidate set in the step (5), then therefrom select and comprise a minimum wave beam candidate set of inactive users, its each user who comprises organizes and obtains current subcarrier pointed; The number of users of channel matrix linear correlation obtains the inactive users quantity Calculation by calculating not on the same group;
(7): organize the transmitting terminal precoding of determining corresponding current subcarrier for the user who obtains subcarrier.Here, if subcarrier is monopolized by user's group, then ask for according to formula (2); If it is shared that subcarrier has a plurality of users to organize, then ask for according to formula (3), (4);
(8): the current data speed of calculating each group that has obtained current subcarrier according to formula (5);
(9):, judge that can its present rate satisfy the rate requirement of this group for each user's group that has obtained current subcarrier; If satisfy execution in step (10); Otherwise execution in step (11);
(10): each user group that current data speed can satisfy its data rate requirement is organized the candidate collection from the user and is removed name from the rolls, then execution in step (11);
(11): judge current whether last subcarrier of pointing system; If, execution in step (12); Otherwise, execution in step (13);
Step (12): last subcarrier of current sensing, then the epicycle subcarrier allocation is finished to this, can obtain the distribution condition of subcarrier and calculate sub-carrier power estimation final value;
The user organizes number and is in the system
Figure 381905DEST_PATH_IMAGE006
, the
Figure 176685DEST_PATH_IMAGE007
The sub-carrier number that individual user organizes acquisition is
Figure 870972DEST_PATH_IMAGE008
, then the subcarrier allocation number of system after multiplexing is
Figure 463146DEST_PATH_IMAGE009
, sub-carrier power estimates that final value is
Figure 508462DEST_PATH_IMAGE010
(13): current is not to point to last subcarrier, and then the next subcarrier of pointing system returns execution in step (3) then;
(14): judge subcarrier just distributes the iterations counting whether to equal its upper limit.If step 1 finishes, subcarrier has just assigned; Otherwise sub-carrier power estimates that initial value is updated to the average of initial value and final value, and makes subcarrier just distribute iterations to increase 1, returns execution in step (2) then;
Fig. 4 has shown the flow process of resource re-allocation algorithm, realize the distribution of base station gross power after, organize and do not reach its rate requirement if be checked through the user, then carry out resource re-allocation, detailed process is presented below:
A: take out such subcarrier from user's group that all data rates require to be met: this subcarrier satisfies group by one to be monopolized, and after removing this subcarrier, this data rate that satisfies group requires still to be met.All subcarriers that meet this condition constitute heavy allocation of subcarriers set, for not satisfying group selection;
B: point to first subcarrier in the heavy allocation of subcarriers set;
C: all do not satisfy group and constitute heavy assign group Candidate Set;
D: arrange each group in the heavy assign group Candidate Set by the descending of the group channel coefficients of the subcarrier correspondence of current sensing;
E: form a wave beam candidate set according to arranging, its user who comprises organizes and obtains current subcarrier, and the formation of wave beam candidate set can just distribute the step (5) of iterative process referring to subcarrier;
F: determine that the user who obtains subcarrier organizes corresponding transmitting terminal precoding, method is just distributed the step (7) of iterative process with subcarrier;
G: the current data speed of calculating each the user's group that obtains heavy allocation of subcarriers according to formula (5).In the formula (5), user's group at existing data rate is , and subcarrier last is taken turns the sub-carrier power that iteration obtains and estimates that initial value is in just distributing
Figure 390148DEST_PATH_IMAGE083
H: judge whether the estimation rate that does not satisfy group that obtains subcarrier reaches requirement; If, execution in step i; Otherwise, carry out j;
I: the estimation rate that does not satisfy group that obtains subcarrier reaches requirement, and then this group is removed name from the rolls from the group Candidate Set, then execution in step j;
J: judge last in the whether heavy allocation of subcarriers set of subcarrier of current sensing; If, execution in step l; Otherwise, execution in step k;
K: the subcarrier of current sensing is not last in the heavy allocation of subcarriers set, then points to the next subcarrier in the heavy allocation of subcarriers set;
L: the subcarrier of current sensing is last in the heavy allocation of subcarriers set, and then subcarrier has heavily assigned, by the power water filling to finish power division.Arrive this, resource re-allocation is finished.

Claims (4)

1. descendingly go into singly to go out-OFDM multicast system resource allocation methods for one kind more, it is characterized in that step is as follows:
1), the power that presets all subcarriers estimates initial value, putting subcarrier, just to distribute iterations be 1, is limited to 4 on the iteration, beginning first run subcarrier just distributes iteration;
Described power estimates that the formula that presets of initial value is:
If sub-carrier number is
Figure 591882DEST_PATH_IMAGE001
, each subcarrier on average by
Figure 29816DEST_PATH_IMAGE002
Individual user organizes shared, and system's gross power is
Figure 385187DEST_PATH_IMAGE003
, the power that then presets estimates that initial value is
Figure 857757DEST_PATH_IMAGE004
,
Figure 908889DEST_PATH_IMAGE005
2), each user's group has its data rate requirement in the system, all users form users and organize candidate collection;
3), for any one current subcarrier that is not assigned with, each user of each user group has corresponding channel fading coefficient in the system, with the group channel fading coefficient of channel fading coefficient minimum in each user's group as this user's group; The user is organized the group channel fading coefficient of each user's group in the candidate collection and do descending; With user's group is that unit divides group channel fading coefficient behind the descending to form an above wave beam candidate set;
4), from the wave beam candidate set that produces, select a wave beam candidate set that comprises minimum inactive users; Described inactive users be come from different user groups but have the different user of the channel matrix of linear correlation, if the wave beam candidate set only comprises a group, then do not have inactive users;
5), if the wave beam candidate set selected only comprises user's group, then this user organizes and obtains this current subcarrier that is not assigned with; Start transmitting terminal precoding algorithm then, ask for the transmitting terminal precoding of the unique user's group that has obtained current subcarrier;
6), if the velocity of wave candidate set of selecting comprises a plurality of user's groups, then the user group that comprises of this wave beam candidate set all obtains current subcarrier, then each user's channel matrix in each the user's group that has obtained current subcarrier is made BD and decompose, organize corresponding transmitting terminal precoding to ask for these users;
7), for the user group that has obtained current subcarrier, calculate the data rate that this subcarrier provides with the shannon formula of correction; The current data rate that all subcarriers provided of having distributed to this user group that adds up obtains the current data speed of this user's group; Judge whether current data speed satisfies the data rate requirement of this user group,, this user's group organized the candidate collection from the user remove name from the rolls if satisfy; If do not satisfy, this user's group still is retained in the user and organizes in the candidate collection; Repeating step 3) to step 7), all subcarriers all obtain distributing in system, and execution in step 8 again);
8), statistical system subcarrier allocation situation, calculate sub-carrier power thus and estimate final value; Judge current subcarrier just distributes iterations whether to equal its upper limit; If equal, then execution in step 9); Otherwise, all sub-carrier power estimate that initial value is updated to the average that former sub-carrier power is estimated initial value and sub-carrier power estimation final value, and make subcarrier just distribute iterations to increase 1, return execution in step 2 then), estimate that with new sub-carrier power initial value carries out distributing iteration at the beginning of next wheel carries;
Described sub-carrier power estimates that the calculating formula of final value is:
The system gross power of setting up departments is
Figure 834120DEST_PATH_IMAGE003
, the user organizes number and is in the system
Figure 996111DEST_PATH_IMAGE006
, the
Figure 57608DEST_PATH_IMAGE007
The sub-carrier number that individual user organizes acquisition is
Figure 279642DEST_PATH_IMAGE008
, then the subcarrier allocation number of system after multiplexing is
Figure 692169DEST_PATH_IMAGE009
, sub-carrier power estimates that final value is
Figure 657851DEST_PATH_IMAGE010
9), the base station gross power is assigned on the subcarrier of each user's group with water-filling algorithm; According to the power division situation, calculate the actual data rate of each user's group, and check whether actual data rate satisfies the data rate requirement of each user's group; If all satisfy, then resource allocation process finishes; Otherwise, execution in step 10);
10), check whether user's group that data rate requires to be met has the subcarrier of monopolizing; If user group has the subcarrier of monopolizing, and remove that the data rate of this user's group requires still to be met behind this subcarrier, then extract this subcarrier; So all data rates of traversal require each user who is met to organize, and the subcarrier that extracts is heavily distributed to data rate require the user who is not met to organize, and heavily distribute to finish subcarrier; Again carry out the power water filling then, system resource allocation finishes.
2. according to claim 1 descendingly go into singly to go out-OFDM multicast system resource allocation methods more, it is characterized in that the concrete steps of an above wave beam candidate set of the described formation of step 3) are:
Figure 839433DEST_PATH_IMAGE011
, wave beam candidate set of definition, will organize the channel fading coefficient and do descending, and the user who ranks first in the descending organized add this wave beam candidate set, this user is organized from descending, remove name from the rolls then; At this moment, if the number of users that comprises of this wave beam candidate set is greater than number of transmit antennas, then the current unique user who comprises of this wave beam candidate set organizes and has constituted this wave beam candidate set, step 3) leave it at that, and only formed a wave beam candidate set; If the customer volume of this wave beam candidate set smaller or equal to number of transmit antennas, is carried out
Figure 966789DEST_PATH_IMAGE012
And step
Figure 866612DEST_PATH_IMAGE013
Figure 370406DEST_PATH_IMAGE012
, the wave beam candidate set customer volume during smaller or equal to number of transmit antennas, seek user's group the residue descending after removing name from the rolls through user's group, make that adding this user organizes the customer volume of back wave beam candidate set still smaller or equal to number of transmit antennas; If find, then this user's group is also added in the wave beam candidate set, again this user's group is removed name from the rolls from the residue descending; If can not find, the current user who comprises of wave beam candidate set organizes and has constituted this wave beam candidate set, defines a new wave beam candidate set then;
Figure 672074DEST_PATH_IMAGE013
, repeating step Up to the descending of group channel coefficients is empty, produces more than one wave beam candidate set thus.
3. according to claim 1 and 2 descendingly go into singly to go out-OFDM multicast system resource allocation methods more, it is characterized in that the described transmitting terminal precoding of step 5) algorithm is specially:
If user's group has
Figure 357450DEST_PATH_IMAGE014
Individual user
Figure 667865DEST_PATH_IMAGE015
, each user is corresponding to the channel matrix and the channel fading coefficient difference of current subcarrier
Figure 558460DEST_PATH_IMAGE016
With
Figure 293198DEST_PATH_IMAGE017
(
Figure 902034DEST_PATH_IMAGE018
), wherein For
Figure 23891DEST_PATH_IMAGE020
The dimension matrix, and
Figure 991847DEST_PATH_IMAGE021
, Be the matrix norm computing; If the optimum precoding of transmitting terminal is
Figure 674949DEST_PATH_IMAGE023
(
Figure 540137DEST_PATH_IMAGE024
), then for other any transmitting terminal precodings
Figure 616677DEST_PATH_IMAGE025
(
Figure 200105DEST_PATH_IMAGE026
) and arbitrarily
Figure 387504DEST_PATH_IMAGE018
All satisfy:
Figure 372778DEST_PATH_IMAGE027
Wherein,
Figure 682536DEST_PATH_IMAGE028
Be the computing of Matrix Conjugate transposition,
Figure 690944DEST_PATH_IMAGE029
In scope
Figure 744350DEST_PATH_IMAGE018
In get the expression formula minimum operation;
Produce several transmitting terminal precodings at random
Figure 518884DEST_PATH_IMAGE025
, therefrom find out the transmitting terminal precoding that to satisfy following formula
Figure 999544DEST_PATH_IMAGE023
, be of the transmitting terminal precoding of this user's group corresponding to current subcarrier.
4. according to claim 3ly descendingly go into singly to go out-OFDM multicast system resource allocation methods more, it is characterized in that the sub-carrier power estimation initial value value during subcarrier described in the step 10) heavily distributes is taken turns subcarrier for last and just distributed the sub-carrier power of iteration gained to estimate initial value; In the heavy assigning process, subcarrier is directly distributed to user's group that first wave beam candidate set comprises, and does not reexamine the inactive users of wave beam candidate set.
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