CN1242629C - A multi-user self-adaptive packet layering spacetime signal sending-receiving system - Google Patents

A multi-user self-adaptive packet layering spacetime signal sending-receiving system Download PDF

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CN1242629C
CN1242629C CN 03131964 CN03131964A CN1242629C CN 1242629 C CN1242629 C CN 1242629C CN 03131964 CN03131964 CN 03131964 CN 03131964 A CN03131964 A CN 03131964A CN 1242629 C CN1242629 C CN 1242629C
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CN1568026A (en
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龚明
邱玲
朱近康
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University of Science and Technology of China USTC
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Abstract

The present invention relates to a signal transmitting and receiving system during multi-user self-adapting grouping and delamination. The present invention is characterized in that antennae of users are grouped in a self-adaptive mode in a base station according to the estimated value of a signal channel response matrix from all users to the base station with a total system theory capacity or the condition number of a signal channel as an optimization target. Grouping information is fed back to the users through a down signal channel, and the antennae of the users are multiplied by orthogonal codes corresponding to a grouping on carrying data. A receiver in the base station divides data signals transmitted through the antennae into a plurality of groups by decoding the orthogonal codes, and a plurality of transmitting antennae in every group and receiving antennae in the base station form a delamination space-time system. Every antenna data demodulated by cancelling a demodulation algorithm is newly ordered to obtain the data of all the users. The present invention combines a traditional uplink multi-user code division multiple access mode, and the performance of the system is enhanced by using the freedom degree of a space signal channel. Particularly, under the condition of a bad space signal channel, the deterioration of the performance of the system can be avoided.

Description

Multi-user self-adaptive grouping layering space-time signal transceiving system
The technical field is as follows:
the invention belongs to the technical field of mobile communication Multiple Input Multiple Output (MIMO) antenna signal processing technology and mobile communication uplink multiple access, and particularly relates to a multi-user self-adaptive grouping and layering space-time signal transceiving system for improving system performance under a non-ideal spatial channel and a grouping optimization method thereof.
Background art:
multiple Input Multiple Output (MIMO) antenna signal processing techniques can increase system capacity and improve system performance by exploiting the degrees of freedom of spatial channels. MIMO technology has become one of the hot spots of research in recent years and has begun to find application in practical systems.
According to the introduction of the proceedings of the International Symposium on Signal, Systems and electronics 1998 (29 Sep-20ct 1998; Page(s): 295-. The multi-path independent data is concurrently transmitted on the multi-path antennas of the transmitting end, the receiving end performs combined processing on all signals received by the multiple antennas, and all the transmitted data is demodulated by utilizing a multi-user interference cancellation algorithm. Because all data are transmitted simultaneously in the same frequency band, no extra communication bandwidth resource is occupied, and the system adopting the V-BLAST technology obviously improves the utilization efficiency of frequency spectrum. However, the V-BLAST technology is a point-to-point communication technology and does not support simultaneous communication by a plurality of users.
The International society of Electrical and electronics Engineers 2001 International Conference on (Communications, IEEE International Conference on, 2001; Page(s): 565-; the multi-user synchronous V-BLAST system utilizes the freedom degree of a space channel, thereby improving the capacity of the system to a certain extent.
However, the orthogonal codes group all antennas, and there are many possible grouping combinations, and under the same channel condition, the system performance caused by various grouping combinations is different; especially, in the case of non-ideal spatial channels, for example, in the case of strong channel correlation between partial transmit-receive antenna pairs, or in the case of "KEYHOLE" (KEYHOLE) phenomenon in the spatial channels, the performance difference caused by different packets is especially significant. Under certain channel conditions, a grouping combination with better performance exists, and how to select the grouping combination with better performance is a problem which is not solved in the prior art; in addition, the channel in the actual system is constantly changing, so the grouping and combining mode of the channel needs to be changed along with the change of the channel, and the performance of the system can be ensured to be optimized all the time. However, there is no report on how to obtain a packet combining mode which is beneficial to improving the system performance.
The technical content is as follows:
aiming at the defects of the prior art, the invention provides a self-adaptive multi-user grouping layering space-time signal receiving and transmitting system applied to an uplink synchronous link of a mobile communication system, wherein a base station selects one of two grouping optimization methods provided by the invention according to the current channel condition from each user to the base station, and can adaptively optimize and group the antennas of each user so as to effectively improve the system performance.
The invention is applied to the multi-user self-adaptive grouping layering space-time signal receiving and transmitting system of the uplink synchronous link of the mobile communication system, which comprises a mobile user transmitting module and a base station receiver (10);
the system is set to comprise K users with numbers of U _1, … and U _ K; the kth mobile subscriber transmission module has mkA transmitting antenna, wherein the K users in the system have M transmitting antennas in total, and the transmitting antenna is marked as [ A ]1,A2,...,AM];
The kth mobile user sending module modulates the data (1) to be sent by the modulating module (2), and the serial-parallel conversion module (3) takes out mk·NdThe continuous modulated data is a data block, which is set as the nth block and converted into mkRoad length of NdEach path of data stream corresponds to one transmitting antenna; the multiplexing module (5) inserts a length N for channel estimation into each data stream in a time division multiplexing mannerpForming a training sequence (4) of length NB=Nd+NpA data stream (7) with training sequences; let T be the duration of each data symbol, and the length of time for the transmission of the nth block of data be TB=NBT, in the time period (n-1) TB~nTBEach data stream (7) with training sequence is multiplied by an orthogonal code sequence (6) assigned to it by the base station for each data symbol duration to form a transmitted signal, this step being called the channelA chemical process; the signals simultaneously transmitted by all the transmitting antennas (8) reach a base station receiver (10) through an uplink channel (9);
an antenna (12) of the base station receiver (10) transmits the received signals of all the users to a de-orthogonal code module (13); the orthogonal code sequences (6) used by the antennas of all users share G different sequences, and the orthogonal code decoding module (13) decomposes the signals of all users into corresponding G grouped signals according to the G different orthogonal code sequences by using the orthogonal code decoding technology, wherein each grouped signal comprises a received signal (15) corresponding to a training sequence and a received signal (14) corresponding to transmission data; for any one of the grouped signals, a channel estimation module (16) takes a received signal (15) corresponding to the training sequence as input, and performs channel estimation for a time period (n-1) T from each transmitting antenna (8) to each base station receiving antenna (12) in the groupB~nTBInner channel HpPerforming channel estimation to obtain a channel estimation value (17); the V-BLAST data demodulation module (19) utilizes the channel estimation value (17) and the receiving signal (14) corresponding to the transmission data and calls a multi-user interference cancellation demodulation algorithm to demodulate the T signal in the time period (n-1)B~nTBData (20) transmitted on all transmit antennas;
the method is characterized in that:
the base station receiver (10) also uses the time period (n-1) T obtained by the channel estimation module (16)B~nTBThe channel estimation value (17) is inputted to an optimization grouping module (18), and the optimization grouping module (18) selects one of the grouping optimization methods (24) given below according to the channel condition, and the selected grouping optimization method is used for the time period nTB~(n+1)TBAll antennas are optimally grouped, and M transmitting antennas (A) of K users are transmitted1,A2,...,AM]Divided into G groups, with scoring group vector F ═ F1,F2,...,FM](25) In which F isiMeans that the ith antenna is divided into FiGroup FiE {1, 2.., G }; the base station informs each user of the time period nT through a downlink feedback channel (11)B~(n+1)TBIn which each antenna is locatedIf the mobile subscriber knows that the ith antenna is classified as p ═ FiIn a group, and setting the unique orthogonal code sequence corresponding to the group as WpLength L, taken from a set of G WALSH (WALSH) codes, W ═ W1,W2,...,WG]At time period nTB~(n+1)TBIn the channelization process, the orthogonal code sequence (6) multiplied by the data stream (7) with the training sequence corresponding to the 1 st antenna is Si=Wp(ii) a The optimized grouping module (18) also transmits the grouping vectors in each time period to a recombination and parallel-serial conversion module (21), and the recombination and parallel-serial conversion module (21) utilizes the grouping vectors (25) of the users corresponding to the data transmission time period to carry out the sequence rearrangement on the data (20) demodulated by the V-BLAST data demodulation module (19), and recovers the data (22, 23) of each corresponding user after the parallel-serial conversion.
One of the grouping optimization methods proposed by the invention for the optimized grouping module (18) is to take the total system theoretical capacity as an optimization target, calculate the sum of weighted channel theoretical capacities in various grouping modes, and select the grouping vector F for maximizing the sumcapI.e. by
F cap = arg max F { C = 1 M Σ p = 1 G M p C p }
Parameters in the formula: packet vector Fcap=[F1,F2,...,Fi,...,FM],FiE {1, 2.., G }; g is the number of packets; m is the total number of transmit antennas in the system; the optimization objective is G capacity values CpThe weighted sum of (a) and (b),
C p = log 2 { det ( I N + ρ p M p H p H p * ) }
is all M in group ppThe transmitting antennas and the N receiving antennas of the base station form an equivalent MpVolume of the V-BLAST subsystem of XN, where INIs a unit array of nxn; mpIs the number of transmit antennas of the pth group; H p = [ h p 1 , h p 2 , . . . , h p M p ] is the channel response matrix of the p-th packet whose elements are also vectors, hi=[h1,ih2,i,...,hN,i]T,[v]TRepresenting the transpose of the vector v, hj,iIs the channel response coefficient from the transmitting element i to the receiving element j; (p)1,p2,...,pMp) Are their corresponding positions in the transmitted sequence; rhopIs the signal-to-noise ratio at the receive antenna of the V-BLAST subsystem formed by the p-th packet.
The second grouping optimization method for the optimized grouping module (18) provided by the invention is to take the condition number of the channel as an optimization target, calculate the sum of the weighted channel matrix condition numbers under various grouping modes, and select the grouping vector F which minimizes the sumcondI.e. by
F cond = arg min F { Cond = 1 M Σ p = 1 G M p · Cond ( H p ) }
Parameters in the formula: packet vector Fcond=[F1,F2,...,Fi,...,FM],FiE {1, 2.., G }; g is the number of packets; cond (H)p) Is HpThe condition number of (1); wherein H p = [ h p 1 , h p 2 , . . . , h p M p ] Is the channel response matrix of the p-th packet whose elements are also vectors, hi=[h1,ih2,i,...,hN,i]T,hi=[h1,ih2,i,...,hN,i]T=[v]T,[v]TRepresenting the transpose of the vector v, hj,iIs the channel response coefficient from the transmitting element i to the receiving element j; (p)1,p2,...,pMp) Are their corresponding positions in the transmitted sequence; h is to bepPerforming SVD singular value decomposition to obtain HpU Λ V, U, V being unitary matrix, diagonal matrix Λ ═ diag { Λ1,Λ2,...,ΛrThe diagonal element in 0pSingular values of, saidThe condition number of the channel is defined as the ratio of the largest singular value to the smallest singular value.
The optimized grouping module (18) can also select other grouping optimization methods according to the channel condition.
Compared with the prior art, the multi-user packet layered space-time signal transceiving system of the invention utilizes the freedom degree of the space channel in a self-adaptive manner, obviously improves the performance of the multi-user system, and can effectively avoid the performance deterioration of the multi-user system especially under the condition that the space channel is not ideal. The wireless communication channel is complex and changeable, and under the same channel, various packet combinations of the multi-user packet layered space-time transceiving system can cause different system performances. In the case of non-ideal spatial channels, for example, the channel correlation between partial transmit-receive antenna pairs is strong, or when KEYHOLE phenomenon occurs, the performance difference between different packets is especially significant, and improper packets may result in the system failing to perform effective communication. If only the conventional multiple access method is used, each user uses a fixed orthogonal code, the system using the multiple antenna technique cannot ensure that the system performance is improved, and when the spatial channel is not ideal, the system performance suffers from serious deterioration. The two grouping optimization methods provided by the invention can ensure that the grouping made by the base station each time is optimized, and the grouping mode based on one of the two methods can divide the antennas with strong correlation into different groups as much as possible and divide the antennas seriously influenced by KEYHOLE into different groups; in each equivalent sub V-BLAST system, an equivalent channel response matrix has a good structure, and the bit error rate is favorably reduced. The channel in a real system varies and the way the packets are combined also needs to vary. The self-adaptive grouping and layering space-time transceiving system provided by the invention provides a self-adaptive grouping platform, can ensure that the optimized grouping result is correctly and timely executed, and ensures that the performance of the system is always optimized. Compared with a fixed grouping mode or a random grouping mode, the multi-user self-adaptive grouping V-BLAST system can effectively improve the performance of the system and improve the reliability of wireless communication.
Description of the drawings:
FIG. 1 is a block diagram of an adaptive packet V-BLAST system for a multi-user transmission section;
fig. 2 is a block diagram of an adaptive packet V-BLAST system of a receiving part of a base station.
FIG. 3 is a graph comparing the performance of the adaptive packet V-BLAST system.
The specific implementation mode is as follows:
embodiments of the present invention are described below with reference to the drawings.
Example 1:
this embodiment takes a synchronous uplink system with K-4 users as an example, and describes the application of the present invention to a multiuser adaptive packet-layered space-time signal transceiving system of an uplink synchronous link in a mobile communication system.
Let each user have 3 transmit antennas, K-4 users have M-12 transmit antennas, and be denoted as [ a1,A2,...,A12]They perform uplink timing synchronization by means of system information. The base station has 4 receiving antennas.
The sending module of the kth user modulates the data (1) to be sent by the modulation module (2), and the serial-parallel conversion module (3) takes 3. NdThe continuous modulated data is a data block, which is set as the nth block and converted into mkLength of 3 channels is NdEach path of data stream corresponds to a transmitting antenna, and the multiplexing module (5) inserts the length N for channel estimation into each path of data stream in a time division multiplexing modepForming a data stream (7) with a training sequence, the length of which is NB=Nd+Np(ii) a Let T be the duration of each data symbol, and the length of time for the transmission of the nth block of data be TB=NBT,Np,NdNeed to be combinedThe speed of channel change is reasonably set, and the requirement is NpGreater than the number of transmitting antennas, TBLess than the channel correlation time, Nd/NpAs large as possible to improve system channel utilization efficiency. At a time period (n-1) TB~nTBEach data stream (7) with training sequence is multiplied by an orthogonal code sequence (6) assigned to it by the base station for each data symbol duration, which is called channelization process; all transmit antennas (8) transmit simultaneously and the signal reaches the base station receiver (10) via an uplink channel (9).
The antennas of all users are arranged in sequence, and the uplink multi-antenna is defined in a time period (n-1) TB~nTBInner channel response matrix: h ═ H1,h2,h3,h4,...,h12]Whose elements are also vectors, hi=[h1,ih2,i...,h4,i]T,hj,iIs the channel response coefficient for the transmit element i to the receive element j. The data streams (7) with training sequences corresponding to the respective multi-antenna channels are arranged in such a way that B ═ B1,b2,b3,...,b12]. Due to the ideal power control in the multi-user system, the difference of the average fading of each user can be not considered, and equivalently, each user transmits data with the same power. A matrix T formed by orthogonal code sequences (6) used by all antennas of all users is set as diag (S)1,S2,...,Si,...,S12)T,SiAn orthogonal code sequence used by the ith antenna is indicated. The signal vector r received on all antennas of the base station (10) is (r ═ r1,r2,...,r4)TComprises the following steps:
r=HTB+n
n is white gaussian noise.
The antenna (12) of the base station receiver (10) sends the received signals of all users to the de-orthogonal code module (13). The orthogonal code sequence (6) used by the antennas of all users has 4 antennasThe same sequence, antennas using different orthogonal code sequences are considered in different groups, assuming that all members of the pth group use orthogonal code WpGroup p has MpAn antenna, their corresponding positions in the transmission sequence are (p)1,p2,...,pMp) The orthogonal code W for the orthogonal code decoding module (13)pAnd a reception signal (12) on the antenna (12): r ═ r (r)1,r2,...,r4)TMake correlation calculation
Figure C0313196400081
The signals of the pth group can be extracted:
rp=(rp1,rp2,...,rp4)T
this MpData stream of one transmitting antenna and r received by N-4 receiving antennas of base stationp=(rp1,rp2,...,rp4)TForm an equivalent MpX 4V-BLAST subsystem:
rp=HpBp+np
wherein n ispIs white gaussian noise and is generated by the noise, B p = [ b p 1 , b p 2 , . . . , b p M p ] T is the data to be transmitted in the subsystem, H p = [ h p 1 , h p 2 , . . . , h p M p ] is the channel response matrix for the p-th packet. Such equivalent V-BLAST subsystems have a total of 4G.
For any one packet, setting the p-th packet, the separated group signal comprises two parts: a received signal (15) corresponding to the training sequence and a received signal (14) corresponding to the transmission data; a channel estimation module (16) receives a received signal (15) corresponding to the training sequence as an input, and performs channel estimation on channels H from each transmission antenna (8) to each base station reception antenna (12) in the p-th packetpPerforming channel estimation to obtain a channel estimation value (17); the V-BLAST data demodulation module (19) utilizes the channel estimation value (17) and the receiving signal (14) corresponding to the transmission data and calls a multi-user interference cancellation demodulation algorithm to demodulate the T signal in the time period (n-1)B~nTBGrouping the data on all antennas in the p-th group, and performing similar demodulation processes on all groups to obtain the data on all antennas in the system (20); the recombination and parallel-serial conversion module (21) utilizes a user grouping vector (25) which is obtained from the following optimized grouping module (18) and corresponds to a sending data time period to carry out the order-sorting of the data (20) demodulated by the V-BLAST data demodulation module (19), and restores the data after the parallel-serial conversion into the corresponding time period (n-1) TB~nTBData (22, 23) of individual users;
the channel estimation module (16) of the present embodiment obtains a time period (n-1) TB~nTBThe channel estimation values (17) from all the transmitting antennas (8) to the receiving antennas (12) of each base station are input into an optimized grouping module (18) besides being used as the input of a V-BLAST data demodulation module (19), and the optimized grouping module (18) selects one of the following 2 grouping optimization methods (24) to carry out the next time period nT according to the channel conditionB~(n+1)TBAll antennas in the antenna are optimally grouped, and the optimized grouping is performed every TBIs carried out once. An optimized grouping module (18) sets K to 4 usersM-12 transmitting antennas [ a ═ a1,A2,...,AM]Dividing into 4 groups, scoring group vector F ═ F1,F2,...,Fi,...,F12]In which F isi∈{1,2,...,4},FiMeans that the ith antenna is divided into FiGroup (d);
grouping vectors when selecting a total system theoretical capacity as an optimization target
F cap = arg max F { C = 1 M Σ p = 1 G M p C p }
Wherein, C p = log 2 { det ( I N + ρ p M p H p H p * ) } ; parameters in the formula: packet vector Fcap=[F1,F2,...,Fi,...,FM],FiE {1, 2,. G },; g is 4 is the number of packets; rhopIs the signal-to-noise ratio at the receive antenna of the p-th packet forming the V-BLAST subsystem; mpIs the number of transmit antennas in the p-th packet; H p = [ h p 1 , h p 2 , . . . , h p M p ] is the channel response matrix of the p-th packet, hi=[h1,ih2,i,...,hN,i]T,hj,iIs the channel response coefficient from the transmitting element i to the receiving element j; i isNIs a 4 × 4 unit array; m-12 is the total number of transmit antennas in the system; f ═ F1,F2,...,F12]Is a grouping vector. The method is to calculate the sum of weighted channel theoretical capacities under various grouping modes and select a grouping mode F which maximizes the sum.
Grouping vectors when selecting a condition number for a channel as an optimization target
F cond = arg min F { Cond = 1 M Σ p = 1 G M p · Cond ( H p ) }
Parameters in the formula: packet vector Fcond=[F1,F2,...,Fi,...,FM],FiE {1, 2.., G }; g is 4 is the number of packets; cond (H)p) Is HpCondition number of (2). The condition number is defined as: h is to bepSingular Value Decomposition (SVD) is carried out to obtain HpU Λ V, U, V being unitary matrix, diagonal matrix Λ ═ diag { Λ1,Λ2,...,Λr0. } has the diagonal element of HpThe condition number is defined as the maximumThe ratio of the singular value of (a) to the smallest singular value. The method is to calculate the sum of weighted channel matrix condition numbers under various grouping modes and select the grouping mode F which minimizes the sum.
The optimized grouping module (18) can also select other grouping optimization methods according to the channel condition.
The optimized grouping module (19) outputs grouping vectors (25), and the base station informs each user of the next time period nT through a downlink feedback channel (11)B~(n+1)TBThe mobile user knows that the ith antenna is divided into the p-th and F-th antennasiWithin a group, the only orthogonal code sequence corresponding to that group is WpLength L4, from a set containing G4 WALSH codes, W ═ W1,W2,...,W4]At the next time period nTB~(n+1)TBIn the channelization process, the orthogonal code sequence (6) multiplied by the corresponding data stream with training sequence (7) on the ith antenna is Si=Wp(ii) a At the same time, time period nTB~(n+1)TBIs also input to the reassembly and parallel-to-serial conversion module (21) such that the time period nT is equal toB~(n+1)TBThe module can correctly recover the data of each user.
The key of the system is that the base station optimizes the packet combination, and the optimization aims are as follows: under the condition of given power and modulation mode, the capacity of the system is given, and the error rate of the system is enabled to be as small as possible. Because the V-BLAST demodulation algorithm has a non-linear interference cancellation process, the bit error rate of the system cannot be quantitatively expressed, and the optimal grouping scheme cannot be accurately found in the grouped V-BLAST. The total system theoretical capacity or the condition number of the channel is two numbers indirectly related to the error rate, and the two numbers are optimized by adopting one of the 2 grouping methods respectively, so that a practical and feasible approximately optimal grouping scheme is obtained, and the performance of the system is obviously improved.
To evaluate the improvement of the present invention to multi-user system performance, computer numerical simulations were performed on a synchronized uplink system with K-4 users. In the simulation, all users adopt a 16QAM digital modulation scheme, the adopted wireless channel model is a quasi-static flat rayleigh fading model, and the spatial channel model with M being 12 transmitting antennas to receiving antennas is a hybrid model, and includes independent channel conditions, related channel conditions, and KEYHOLE channel conditions.
H=[H1,H2,H3,H4,...,H12]=[A,B,C,D],Hi=[H1,iH2,i...,H4,i]T,Hj,iIs the channel response coefficient for the transmit element i to the receive element j. Wherein A ═ H1,H2,H3]And B ═ H4,H5,H6]Each element in the system is a complex Gaussian random variable which is independently and identically distributed. C ═ H7,H8,H9]Is a channel with spatial correlation, D ═ H10,H11,H12]Is the channel model in the presence of the KEYHOLE phenomenon. If each antenna of the same user uses the same orthogonal code according to user grouping, the corresponding grouping vector is F ═ 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4]This is exactly the same as in the conventional multi-user multiple access case, where orthogonal codes are used to distinguish users. The channel matrices for each equivalent V-BLAST subsystem are exactly A, B, C, D. This way of grouping by users serves as a reference comparison case at the time of evaluation. Similarly, randomly grouping M-12 transmit antennas is also a reference comparison case. A comparison of the performance of the adaptive packet V-BLAST system is given in FIG. 3. The abscissa of the graph is the average signal-to-noise ratio in dB and the ordinate is the average bit error rate of the system. Curve 1 gives the performance of the system grouped with method 1, curve 2 gives the performance of the system grouped with method 2, curve 3 gives the performance of the system grouped randomly, and curve 4 gives the performance of the system grouped by user. As can be seen, the fixed user-grouped approach degrades performance extremely under such non-ideal channel conditions. The performance of the random grouping approach is also not ideal. For more fixed or random packet mode, multi-user adaptationThe packet V-BLAST system can effectively improve the system performance and the reliability of wireless communication under two optimization methods provided by the invention.

Claims (3)

1. A multi-user adaptive packet layered space-time signal transceiving system applied to an uplink synchronous link of a mobile communication system includes a mobile user transmission module and a base station receiver (10);
the system is set to comprise K users with the numbers of U _ 1., U _ K; the kth mobile subscriber transmission module has mkA transmitting antenna, wherein the K users in the system have M transmitting antennas in total, and the transmitting antenna is marked as [ A ]1,A2,...,AM];
The kth mobile user sending module modulates the data (1) to be sent by the kth mobile user sending module by a modulation module (2)The serial-parallel conversion module (3) takes out mk·NdThe continuous modulated data is a data block, which is set as the nth block and converted into mkRoad length of NdEach path of data stream corresponds to one transmitting antenna; the multiplexing module (5) inserts a length N for channel estimation into each data stream in a time division multiplexing mannerpForming a training sequence (4) of length NB=Nd+NpA data stream (7) with training sequences; let T be the duration of each data symbol, and the length of time for the transmission of the nth block of data be TB=NBT, in the time period (n-1) TB~nTBEach data stream (7) with training sequence is multiplied by an orthogonal code sequence (6) assigned to it by the base station for each data symbol duration to become a transmitted signal, which is called channelization process; the signals simultaneously transmitted by all the transmitting antennas (8) reach a base station receiver (10) through an uplink channel (9);
an antenna (12) of the base station receiver (10) transmits the received signals of all the users to a de-orthogonal code module (13); the orthogonal code sequences (6) used by the antennas of all users are set to share G different sequences, and the orthogonal code decoding module (13) decomposes the signals of all users into G corresponding grouped signals according to the G different orthogonal code sequences, wherein each grouped signal comprises a received signal (15) corresponding to a training sequence and a received signal (14) corresponding to transmission data; for any one of the grouped signals, a channel estimation module (16) takes a received signal (15) corresponding to the training sequence as input, and performs channel estimation for a time period (n-1) T from each transmitting antenna (8) to each base station receiving antenna (12) in the groupB~nTBInner channel HpPerforming channel estimation to obtain a channel estimation value (17); a layered space-time data demodulation module (19) utilizes the channel estimation value (17) and the receiving signal (14) corresponding to the transmission data and calls a multi-user interference cancellation demodulation algorithm to demodulate the signal in the time period (n-1) TB~nTBData (20) transmitted on all transmit antennas;
the method is characterized in that:
the base station receiver (10) further obtains a channel estimation module (16)Time period (n-1) TB~nTBThe channel estimation value (17) in the time slot is input into an optimized grouping module (18), and the optimized grouping module (18) selects a grouping optimization method (24) for the time slot nTB~(n+1)TBAll antennas are optimally grouped, and M transmitting antennas (A) of K users are transmitted1,A2,...,AM]Divided into G groups, with scoring group vector F ═ F1,F2,...,FM](25) In which F isiMeans that the ith antenna is divided into FiGroup FiE {1, 2.., G }; the base station informs each user of the time period nT through a downlink feedback channel (11)B~(n+1)TBThe mobile user knows that the ith antenna is divided into the p-th and F-th antennasiIn a group, and setting the unique orthogonal code sequence corresponding to the group as WpLength L, taken from a set of G walsh codes, W ═ W1,W2,...,WG]At time period nTB~(n+1)TBIn the channelization process, the orthogonal code sequence (6) multiplied by the data stream (7) with the training sequence corresponding to the ith antenna is S1=Wp(ii) a The optimized grouping module (18) also transmits the grouping vectors in each time period to a recombination and parallel-serial conversion module (21), and the recombination and parallel-serial conversion module (21) utilizes the grouping vectors (25) of the users corresponding to the data sending time period to orderly recombine the data (20) demodulated by the layered space-time data demodulation module (19) and recover the data (22, 23) of each corresponding user after parallel-serial conversion.
2. The multi-user adaptive packet-layered space-time signal transmission and reception system according to claim 1, wherein the packet optimization method (24) selected by the optimized packet module (18) is to calculate the sum of the weighted channel theoretical capacities in various packet modes and to select the packet vector F that maximizes the sumcapI.e. by
F acp = arg max F { C = 1 M Σ p = 1 G M p C p }
Parameters in the formula: packet vector Fcap=[F1,F2,...,Fi,...,FM],FiE {1, 2.., G }; g is the number of packets; m is the total number of transmit antennas in the system; the optimization objective is G capacity values CpThe weighted sum of (a) and (b),
C p = log 2 { det ( I N + ρ p M p H p H p * ) }
is all M in group ppThe transmitting antennas and the N receiving antennas of the base station form an equivalent MpX N capacity of a layered space-time subsystem, wherein INIs a unit array of nxn; mpIs the number of transmit antennas of the pth group; H p = [ h p 1 , h p 2 , · · · , h pM p ] is the channel response matrix of the p-th packet whose elements are also vectors, hi=[h1,ih2,i,...,hN,i]T=[v]T,[v]TRepresenting the transpose of the vector v, hj,iIs the channel response coefficient from the transmitting element i to the receiving element j; (p)1,p2,...,pMp) Are their corresponding positions in the transmitted sequence; rhopIs the signal-to-noise ratio at the receive antenna of the layered space-time subsystem formed by the p-th packet.
3. The multi-user adaptive packet-layered space-time signal transceiving system according to claim 1, wherein said packet optimization method (24) selected by said optimized packet module (18) is a method of calculating a sum of weighted channel matrix condition numbers for each packet mode and selecting a packet vector F that minimizes the sumcondI.e. by
F cond = arg min F { Cond = 1 M Σ p = 1 G M p · Cond ( H p ) }
Parameters in the formula: packet vector Fcond=[F1,F2,...,Fi,...,FM],FiE {1, 2.., G }; g is the number of packets; cond (H)p) Is HpThe condition number of (1); wherein H p = [ h p 1 , h p 2 , · · · , h pM p ] Is the channel response matrix for the p-th packet,its elements are also vectors, hi=[h1,ih2,i,...,hN,i]T,hi=[h1,ih2,i,...,hN,i]T=[v]T,[v]TRepresenting the transpose of the vector v, hj,iIs the channel response coefficient from the transmitting element i to the receiving element j; (p)1,p2,...,pMp) Are their corresponding positions in the transmitted sequence; h is to bepSingular value decomposition is carried out to obtain HpU Λ V, U, V being unitary matrix, diagonal matrix Λ ═ diag { Λ1,Λ2,...,ΛrThe diagonal element in 0pThe condition number of the channel is defined as the ratio of the largest singular value to the smallest singular value.
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