Disclosure of Invention
The invention provides a scheduling method and a scheduling system for a space division multiple access system, which achieve the purpose of improving the throughput of the SDMA system.
The invention provides a scheduling method for a space division multiple access system, which comprises the following steps:
respectively obtaining the maximum of each user on each resource block according to the effective post-processing signal-to-noise ratio of each userA large number of transmission bits; the method specifically comprises the following steps: using formula SINR
i,k=||H
i,k||
2·SNR
iRespectively calculating a plurality of post-processing signal-to-noise ratios of each user; wherein, the SINR
i,kPost-processing signal-to-noise ratio, H, for the ith user on the kth subcarrier
i,kChannel gain matrix, SNR, on k sub-carrier for ith said user
iFor receiving the snr, i is 1, 2, 3, N, K is 1, 2, 3, K, i denotes a user, N denotes the number of users, K denotes a subcarrier, and K denotes the number of subcarriers; effectively combining a plurality of post-processing signal-to-noise ratios of each user to obtain an effective post-processing signal-to-noise ratio of each user on each resource block; according to the effective post-processing signal-to-noise ratio, utilizing a formula r
i,u=log
2(1+βESINR
i,u) Calculating the maximum transmission bit number of each user on each resource block; wherein r is
i,uFor the maximum transmission bit number, ESINR, of the ith user on the u-th resource block
i,uRepresenting the effective post-processing snr for the ith said user on the u-th resource block,
BER is bit error rate;
determining a user to be transmitted for each resource block according to the maximum transmission bit number of each user on each resource block;
carrying out user pairing on the users to be transmitted to obtain a transmission user pair, wherein the transmission user pair simultaneously transmits data on the same resource block;
determining and updating an average transmission rate for a plurality of said users.
The step of determining a user to be transmitted for each resource block according to the maximum transmission bit number of each user on each resource block specifically includes:
using formulas
Calculating a proportional fair scheduling (PF) factor for each of the users, wherein P
iScheduling PF factor, R for the proportional fair
iIs the average transmission rate of the ith said user.
And selecting the user with the maximum proportional fair scheduling PF factor as the user to be transmitted on the u-th resource block.
The step of determining and updating the average transmission rates of the plurality of users specifically includes:
using formulas
And determining and updating the average transmission rate of the users at the current moment, wherein T is the size of an average window, U represents a resource block, and U represents a resource block set. .
The embodiment of the invention also provides a dispatching system for space division multiple access, which comprises:
a maximum transmission bit determining unit, configured to obtain a maximum transmission bit number of each user on each resource block according to an effective post-processing signal-to-noise ratio of each user; the maximum transmission bit determining unit specifically includes: a post-processing signal-to-noise ratio calculation module for utilizing formula SINRi,k=||Hi,k||2·SNRiRespectively calculating a plurality of post-processing signal-to-noise ratios of each user; wherein, the SINRi,kPost-processing signal-to-noise ratio, H, for the ith user on the kth subcarrieri,kChannel gain matrix, SNR, on k sub-carrier for ith said useriFor receiving the snr, i is 1, 2, 3, N, K is 1, 2, 3, K, i denotes a user, N denotes the number of users, K denotes a subcarrier, and K denotes the number of subcarriers; an effective combining module, configured to effectively combine the multiple post-processing signal-to-noise ratios of each user to obtain an effective post-processing signal-to-noise ratio ESINR of each user on each resource block; maximum transmission bit calculation module for using formula ri,u=log2(1+βESINRi,u) Calculating the maximum transmission bit number of each user on each resource block; wherein r isi,uFor the maximum transmission bit number, ESINR, of the ith user on the u-th resource blocki,uRepresenting the effective post-processing snr for the ith said user on the u-th resource block,BER is bit error rate;
a unit for determining the user to be transmitted, which is used for determining the user to be transmitted for each resource block according to the maximum transmission bit number of each user on each resource block;
the user pairing unit is used for carrying out user pairing on the users to be transmitted to obtain transmission user pairs, and the transmission user pairs transmit data on the same resource block simultaneously;
and the average rate updating unit is used for determining and updating the average transmission rate of the plurality of users.
The unit for determining the user to be transmitted specifically includes:
a PF factor calculation module for proportional fair scheduling using a formula
Calculating the proportional fair scheduling PF factor of each user on the u-th resource block, wherein P
iScheduling PF factor, R for the proportional fair
iAn average transmission rate for the ith said user;
and the selecting unit is used for selecting the user with the maximum proportional fair scheduling PF factor as the user to be transmitted on the u-th resource block according to the calculation result of the proportional fair scheduling PF factor calculation module.
In summary, the present invention provides a scheduling method and system for SDMA system, and the scheduling method and system of the present invention can achieve the purpose of improving the throughput of SDMA system on the basis of not affecting the fairness of users.
Detailed Description
The method and system of the embodiments of the present invention are described in detail below.
The process of the invention will first be described in detail.
The method mainly comprises the following steps: respectively obtaining the maximum transmission bit number of a plurality of users according to the effective post-processing signal-to-noise ratios and the channel gain matrix of the users;
determining a user to be transmitted according to the maximum transmission bit number of the users;
carrying out user pairing on the users to be transmitted to obtain a transmission user pair, and simultaneously transmitting data by the output user pair;
updating an average transmission rate for a plurality of said users.
Specifically, as shown in fig. 1, a resource block set is set as U, and for all resource blocks, resource allocation is performed according to the following steps, where the steps include:
step 11, for N users, respectively according to the SNR of the received signal to noise ratioi(i ═ 1, 2, 3.., N) and a channel gain matrix Hi,k(i 1, 2, 3.., N, K1, 2, 3.., K.), calculates the SINR (post-processing signal-to-noise ratio) of each user on resource block u,
SINRi,k=||Hi,k||2·SNRi (1);
step 12, effectively combining all SINRs of each user to obtain ESINR (effective post-processing signal-to-noise ratio);
step 13, according to the ESINR of each user obtained in step 12: ESINRi,k(i 1, 2, 3.., N) calculating the maximum number of transmission bits per user on resource block u
ri,u=log2(1+βESINRi,u) (2)
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step 14, according to the maximum transmission bit number r of each user obtained in step 13i,u(i ═ 1, 2, 3.. the PF factor on resource block u is calculated for each user
Wherein Ri is the average transmission rate of user i;
step 15, selecting the user j with the maximum PF factor (j ═ arg)maxipi) Transmitting data on a resource block u;
step 16, selecting a user group paired with the user j by using a certain user pairing method and simultaneously transmitting data on the resource block u, wherein the user pairing method can be random pairing RPS, orthogonal pairing OPS, determinant pairing DPS, post-processing SINR pairing SINR-PS and the like, the user pairing method has a detailed solution, and details are not repeated herein;
step 17, determining the transmission bit number of each user on all resource block sets at the current moment, and updating the average transmission rate of all users
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Where T is the size of the averaging window.
After obtaining a plurality of the average transmission rates, if the average transmission rates of a plurality of the users are added, the system throughput of the space division multiple access system can be determined.
The method of the present invention is further described below by way of example, where a single-cell system is set, one transmitting antenna is provided for a user, two receiving antennas are provided for a base station, and the set cell includes 60 users, and the users are uniformly distributed in the cell. The system adopts DFT-SOFDMA (discrete Fourier transform spread spectrum orthogonal frequency division multiple access) mode, divides 600 useful subcarriers into 8 mutually orthogonal resource blocks, each resource block continuously occupies 75 subcarriers, and two users are selected on each resource block for paired transmission.
At each scheduling time, the base station knows the received signal-to-noise ratio (SNR) of each useri(i ═ 1, 2, 3.., 60) and the channel gain matrix H for the user on each carrieri,k(i=1,2,3,...,60;k=1,2,3,...,600);
Calculating the SINR of the 60 users on all the subcarriers by using the formula (1) respectively: SINRi,k(i 1, 2.., 60; k 1, 2.., 600); thus each user is 75 SINRs on all carriers;
for 8 resource blocks, each user performs effective SNR combination on all SINR obtained by the user, and obtains ESINR of all users on 8 resource blocks respectively: ESINRi,u(i 1, 2.., 60; u 1, 2.., 8); the specific process of the effective SNR combining is not described herein again because a successful solution exists in the prior art;
the users are allocated for all 8 resource blocks in the following way:
calculating the maximum transmission bit number r of all users on the resource block u according to the formula (2)i,u(i=1,2,...,60);
According to the obtained maximum transmission bit number r of each user on the resource block ui,uCalculating PF factor P of each user on resource block u by using formula (3)i(i=1,2,...,60);
Selecting the user j with the maximum PF factor (j is argmax)ipi) The user to be transmitted on the resource block u is obtained;
selecting one user from the rest user set L (L is 1, 2, 60; L is not equal to j) to pair with the user j to transmit data by using SINR-PS/DPS user pairing algorithm;
updating the average transmission rate R of all users using equation (4)i(i=1,2,3,...,60)。
To illustrate the effectiveness of the present invention, the simulation results obtained for this particular example are given below, with the simulation parameters assumed to be given in the attached table.
TABLE 1 comparison of the present invention with RR Algorithm in DPS user pairing
TABLE 2 comparison of the present invention with RR algorithm in SINR-PS user pairing
From table 1 and table 2, it can be seen that the system throughput performance is greatly improved by using the scheduling method in the SDMA system according to the embodiment of the present invention. Wherein, for the DPS user pairing algorithm, the effective throughput of the system is increased by 39.1%; for the SINR-PS user pairing algorithm, the effective throughput of the system is improved by 27.6%.
The system according to the embodiment of the present invention will be described in detail with reference to fig. 2.
As shown in fig. 2, the system according to the embodiment of the present invention specifically includes: a maximum transmission bit determining unit, a to-be-transmitted user determining unit, a user pairing unit, and an average rate updating unit, which are described in detail below.
A maximum transmission bit determining unit, configured to obtain maximum transmission bit numbers of multiple users according to effective post-processing signal-to-noise ratios and channel gain matrices of the multiple users, respectively; specifically, the maximum transmission bit determining unit includes:
a post-processing signal-to-noise ratio calculation module for calculating the SINR according to the formulai,k=||Hi,k||2·SNRiRespectively calculating post-processing signal-to-noise ratios of a plurality of users; wherein, the SINRi,kFor post-processing of the signal-to-noise ratio, Hi,kChannel gain matrix, SNR, for said useriFor the received signal-to-noise ratio, i is 1, 2, 3., N, K is 1, 2, 3., K;
an effective combination module, which is used for effectively combining the post-processing signal-to-noise ratios of each user according to the post-processing signal-to-noise ratios of each user obtained from the post-processing signal-to-noise ratio calculation module to obtain an effective post-processing signal-to-noise ratio ESINR of each user; the specific process of the effective merging has a successful solution in the prior art, and is not described herein again;
a maximum transmission bit calculation module for utilizing a formula r according to the effective post-processing signal-to-noise ratio
i,u=log
2(1+βESINR
i,u) Calculating the maximum transmission bit number of a plurality of users; wherein r is
i,uIs the maximum number of transmission bits for the user,
the BER is a bit error rate.
A to-be-transmitted user determining unit, configured to determine a to-be-transmitted user according to the maximum transmission bit number of the multiple users; specifically, the transmission user determining unit specifically includes:
a PF factor calculating module for proportional fair scheduling according to a formula
Calculating a proportional fair scheduling (PF) factor for a plurality of said users over a resource block,wherein, P
iScheduling PF factor, R for the proportional fair
iAn average transmission rate for the user;
and the selection unit is used for selecting the user with the maximum proportional fair scheduling PF factor as the user to be transmitted according to the calculation result of the proportional fair scheduling PF factor calculation module.
The user pairing unit is used for carrying out user pairing on the users to be transmitted to obtain a transmission user pair, and the output user pair simultaneously transmits data; specifically, a user group paired with a user j is selected by using a certain user pairing method and data is transmitted on a resource block u, the user pairing method can be a random pairing RPS, an orthogonal pairing OPS, a determinant pairing DPS, a post-processing SINR pairing SINR-PS and the like, the user pairing method has a detailed solution, and details are not repeated here;
and the average rate updating unit is used for updating the average transmission rates of the plurality of users.
After obtaining a plurality of the average transmission rates, if the average transmission rates of a plurality of the users are added, the system throughput of the space division multiple access system can be determined.
To sum up, the embodiments of the present invention provide a scheduling method and system for sdma, which mainly use the formula SINRi,k=||Hi,k||2·SNRiRespectively calculating a plurality of post-processing signal-to-noise ratios of each user, and effectively combining the plurality of post-processing signal-to-noise ratios of each user to obtain an effective post-processing signal-to-noise ratio; according to the ESINR, using the formula ri,u=log2(1+βESINRi,u) Calculating the maximum transmission bit number of a plurality of users; then, scheduling multiple users, selecting one user to be transmitted, pairing the users to obtain a transmission user pair, and transmitting data at the same time; finally, the average transmission rate of a plurality of users is determined and updated. The scheduling method and the scheduling system of the invention achieve the fairness without influencing usersAnd the throughput of the SDMA system is improved.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.