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WO2012088993A1 - Procédé de transmission basé sur un précodage sans livre de codes dans un système mimo - Google Patents

Procédé de transmission basé sur un précodage sans livre de codes dans un système mimo Download PDF

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Publication number
WO2012088993A1
WO2012088993A1 PCT/CN2011/083374 CN2011083374W WO2012088993A1 WO 2012088993 A1 WO2012088993 A1 WO 2012088993A1 CN 2011083374 W CN2011083374 W CN 2011083374W WO 2012088993 A1 WO2012088993 A1 WO 2012088993A1
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WO
WIPO (PCT)
Prior art keywords
channel
signal
matrix
decomposition
precoding
Prior art date
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Ceased
Application number
PCT/CN2011/083374
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English (en)
Chinese (zh)
Inventor
李立华
张平
高向川
孙奇
宋磊
徐晓亮
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Beijing University of Posts and Telecommunications
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Beijing University of Posts and Telecommunications
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Filing date
Publication date
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Publication of WO2012088993A1 publication Critical patent/WO2012088993A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0621—Feedback content
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/02—Arrangements for detecting or preventing errors in the information received by diversity reception
    • H04L1/06—Arrangements for detecting or preventing errors in the information received by diversity reception using space diversity
    • H04L1/0618—Space-time coding
    • H04L1/0631—Receiver arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/02—Arrangements for detecting or preventing errors in the information received by diversity reception
    • H04L1/06—Arrangements for detecting or preventing errors in the information received by diversity reception using space diversity
    • H04L1/0618—Space-time coding
    • H04L1/0637—Properties of the code
    • H04L1/0656—Cyclotomic systems, e.g. Bell Labs Layered Space-Time [BLAST]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/0204—Channel estimation of multiple channels

Definitions

  • the present invention relates to the field of communications technologies, and in particular, to a non-codebook precoding (SLQD) based transmission method for use in a MIMO system.
  • SQD non-codebook precoding
  • MIMO Multiple Input Multiple-Output
  • the laboratory's Fosdiini et al. proposed a simple vertical layered space-time code (1 ⁇ 2iica), and its experimental system achieved a spectral efficiency of up to: 20 40 Bits/Hz. (4 transmitting antennas and 8 receiving antennas).
  • the maximum likelihood detection is optimal reception in the sense that the bit error rate is the smallest, but the decoding complexity increases exponentially with the number of antennas and the number of modulation constellation points.
  • the ZF-OSIC (ZF-OSIC, zero forcing-optimal successive interference cancellation), based on the zero-forcing quasi-interference cancellation, detects the signal of each layer separately, and can achieve better performance, but it is necessary to detect each layer.
  • the signal needs to calculate the matrix pseudo-inverse, the process complexity is high, which is difficult to apply in the actual system.
  • a sorted QL (SQLD, non-codebook precoding) decomposition detection algorithm is proposed, the algorithm The detection complexity of the system is reduced, but the detection algorithm is usually difficult to obtain an optimal detection order, and since the error propagation has a great influence on the system performance, the BER performance is also normal, when the transmitter knows the channel.
  • Frequency Division Duplexing and Time Division Duplexing (TDD) are two kinds of current, commonly used in communication systems.
  • Duplex mode In the FDD mode mobile 3 ⁇ 4f system, it receives and transmits on two separate symmetric frequency channels. The frequency band is protected to separate the receiving and transmitting channels, and in the TDD mode mobile communication system, different time slots using the same frequency carrier are received and transmitted as bearers of the channel, and the separation of the receiving and transmitting channels is ensured by the time interval.
  • the channel parameters of the uplink and downlink are basically the same, and this property is called channel reciprocity of the TDD system. Therefore, in the FDD MIMO system.
  • the base station can obtain partial or complete channel information through feedback to implement precoding technology. In the TDD MIMO system, based on the existence of the reciprocity of the foregoing channel, the base station can be in need of anti-township.
  • the receiving end obtains channel state information 13 through channel estimation, and the received signal is ⁇ :: H f x + , Liu Dao estimated knot.:
  • M 0 VBLAST system includes M s subchannels, and the receiving end detects the MM0 subchannel layer by layer, wherein the detection sequence is from the subchannel 1 to the subchannel. M f , and the detected transmission signal of the / / subchannel is detected.
  • X the process is as follows:
  • the element representing the /th row and the /column of the lower triangular matrix L is the processed 1 signal of the first subchannel, and represents a constellation decision operation for demodulating the signal.
  • the serial interference cancellation (SIC) technique involved in the above description is an interference cancellation technique, and the detection order is critical to the performance of the SIC.
  • the MIMO signal is converted into different gains ; the subchannels _, the interference of the front layer is removed in order from the top layer to the bottom layer, and then the traceback is performed.
  • Layer data flow if the front layer data stream can be correctly decoded, the interference to the current layer can be completely eliminated without causing interference.
  • the spatial freedom of each subchannel is proportional to the number of layers.
  • the first layer of KP does not fully utilize the diversity gain of multiple antennas, and the spatial freedom is minimal. Because it is the first detection layer, it has the greatest influence on the error propagation of the latter layer, which limits the bit error rate performance of its 3 ⁇ 4 layers, thus limiting the overall bit error rate performance of the system, which is mentioned in the above. Bottleneck effect.
  • the existing technology includes adding a sorting process in the QL decomposition step, which requires QL decomposition of the column vector with the largest gain in the channel matrix, that is, the subchannel with the largest gain.
  • a MIMO-VBLAST transmission system with 8 transmit antennas and 8 receive antennas is studied, wherein the abscissa indicates the detection order of each layer subchannel, and the vertical coordinate indicates that a sufficient number of channel matrix information is performed.
  • the average of the gains of the sub-channels obtained by the SQLD is a statistical average, which is the technique used by the conventional receiver. It can be clearly seen from the towel that the sub-channel access detection order of each layer after the SQLD operation is still basically from the small to the large, which is still very disadvantageous for suppressing the error propagation.
  • the technical problem to be solved by the present invention is how to design a precoding matrix by using known channel information at the transmitting end, and then precoding the data symbols and pilots, thereby improving the error propagation effect when the SIC detection is applied at the receiving end, thereby reducing Interference between subchannels of small MMOs.
  • the present invention provides a non-codebook precoding based transmission method for a MIMO system, where the method specifically includes:
  • S11 acquiring the channel state information of the time and sorting the LQ decomposition operation, obtaining the unitary matrix and the lower triangular matrix and setting the 3 ⁇ 4 as the precoding matrix;
  • the channel-coded and symbol-modulated signal to be transmitted X and the inserted pilot are simultaneously pre-coded, and the pre-coded signal is sent to the ⁇ time transmission channel;
  • S22 Perform a serial interference cancellation on the received signal according to the lower triangular matrix L, and perform symbol demodulation and decoding in sequence.
  • the sender obtains the state of the message at the time according to the reciprocity of the uplink and downlink channels of the time division duplex TDD.
  • the process of performing the QR decomposition on the matrix Hf specifically includes:
  • the process of the symbol-modulated signal to be transmitted X and the pilot inserted into the to-be-transmitted signal simultaneously pre-coding the pre-coding includes: simultaneously transmitting the to-be-transmitted signal X and the pilot Multiplying the precoding matrix 3 ⁇ 4 obtained in the step Sli.
  • the row ', the element of the column of the lower triangular matrix Lf , and the processed signal of the first subchannel are indicated, and the decision operation of the constellation for demodulating the signal is indicated.
  • step S11 and the lower triangular matrix involved in step S22 the elements on the diagonal line are large by probability.
  • Figure 1 is a schematic diagram showing the comparison of the average bit error rate performance of a conventional QL and SQLD operation system
  • FIG. 2 is a schematic diagram of an embodiment of transmission in a MIMO system based on SLQD operation
  • FIG. 3 is a flow chart of a non-codebook precoding based transmission method in a MIMO system according to the present invention
  • FIG. 4 is a schematic diagram showing a comparison of gain average values of sub-channels obtained by performing QL SQLD, LQ, and SLQD on a sufficient number of channel matrix information;
  • FIG. 5 is a schematic diagram showing the comparison of the average bit error rate performance of a system operated by LQ and SLQD according to the technical solution of the present invention. detailed description
  • the present invention provides a sorted LQ decomposition precoding technique, which arranges the MIMO layer subchannel gains at the receiving end in descending order with maximum probability, which is beneficial to suppress the error of the receiving end in performing continuous interference cancellation detection.
  • Code propagation; and by adding rows to make the gain of each layer tend to be consistent, improve the bottleneck effect in SIC detection, and effectively improve the BER performance of the system.
  • the core idea of the technical solution is that the sender uses the obtained channel information for SLQD decomposition (sorted LQ decomposition) to obtain a precoding matrix, and according to the precoding matrix, the precoding is performed simultaneously on the transmission signal and the inserted pilot;
  • the receiving end performs channel estimation on the pilot signal that completes the precoding, and obtains a lower triangular matrix L obtained by decomposing the SLQD at the transmitting end, and then processes the received signal by using the SIC technique to eliminate a certain layer of subchannel signals from the front layer.
  • the data stream detection of each subchannel is completed layer by layer; wherein the lower triangular matrix is used: the diagonal elements of L are arranged in descending order of probability, and serial interference is removed for the received signal Processing, and obtaining the final MIMD decoded signal.
  • the non-codebook precoding based transmission method in the MIMO system according to the present invention includes the following steps:
  • the transmitting end can obtain channel state information by channel reciprocity
  • S202 Sorting the acquired channel state information by L ( ⁇ , ie, SLQD operation, obtaining a unitary matrix and a lower triangular matrix and setting the precoding matrix; the step specifically includes:
  • the channel state information H is conjugate-transposed to obtain Hf, and then the QR is sorted, specifically Process such as
  • S203 performing, by using a unitary matrix, a signal that is encoded and symbol-modulated, and a pilot that is inserted into the transmission signal, and performing precoding, where the signal to be transmitted X and the pilot are simultaneously related to the step.
  • precoding matrix obtained by multiplying S202; complete and then the current pre-coded signal into the 'transmission channel at time t H; in;
  • S204 Perform channel estimation according to the pilot that completes the precoding, and obtain a channel estimation result ⁇ ⁇ ⁇ ⁇ ⁇ , Q t ⁇ L ⁇ ⁇ Q t - , and the superscript conjugate transpose; wherein the channel estimation algorithm that can be used includes: Least squares method, minimum mean square error method and channel estimation algorithm based on Fourier transform;
  • SIC scrambling serial interference cancellation
  • the serial interference cancellation process may be completed by layer-by-layer detection of the sub-channel; the multiple-input multiple-output system includes sub-channels, and the detection sequence may be from sub-channel 1 to sub-channel, and The detected transmission signal of the first subchannel is
  • the elements representing the first row and the second column of the lower triangular matrix L are processed and received signals of the first subchannel, and represent a decision operation on the constellation of signal demodulation.
  • the elements on the diagonal are real numbers arranged in descending order of probability.
  • the abscissa indicates the detection order of each layer subchannel
  • the vertical coordinate indicates the average value of the gain of each layer subchannel obtained by performing QL, SQLD, LQ, and SLQD operations on a sufficient number of channel matrix information. Look at the order
  • FIG. 5 is a transmission model diagram of an embodiment of the present invention.
  • the transmitting end obtains channel information by using channel reciprocity of the TDD system, and the specific step is:
  • the transmitting end performs channel coding on the initial bit-level transmitting signal b.
  • the Turbo code and the equal channel coding manner are used;
  • S502 The transmitting end performs symbol modulation on the channel-coded bit-level signal to obtain ⁇ ⁇ 1 ⁇ 2 , ..3 ⁇ 4; Can adopt QPSK:, I6QAM, 64QAM and other modulation methods;
  • the transmitting end inserts a pilot; preferably, the frequency division, the time division, the code division, etc. may be implemented;
  • the transmitting end directly utilizes the channel reciprocity of the TDD to obtain the channel state information at the moment ⁇ ;
  • S505 The sender side performs SLQD to obtain a unitary matrix, and the elements on the diagonal are real numbers and are arranged in descending order of probability: L f ;
  • the receiving end feeds back the equivalent channel information ⁇ ;
  • L 'M t M t where, representing the elements of the . / row, column of the lower triangular matrix L, ⁇ is the processed / / subchannel of the processed 0 Receive signal, ⁇ G) represents the constellation decision operation for signal demodulation;
  • Step 509 The receiving end completes symbol demodulation of the signal after the MIMO sub-signal detection; wherein, the demodulation mode corresponds to the symbol modulation mode of the transmitting end;
  • Step 510 The receiving end performs channel decoding on the demodulated bit-level signal to obtain a decoded signal 6; wherein, the signal decoding mode corresponds to the signal encoding mode of the transmitting end.
  • the present invention combines a transmitter precoding and a receiving end MIMO subchannel SIC detection algorithm, wherein the transmitting end performs a SLQD (sorted LQ decomposition) operation according to channel state information to obtain a unitary matrix Q, and the elements on the diagonal are basically The lower triangular matrix arranged in descending order: L, taking Q as a precoding matrix, and then using the precoding matrix to complete precoding of the transmitted signal and the pilot; the receiving end performs channel estimation on the pilot signal that completes the precoding, and obtains the transmitting end.
  • SLQD sorted LQ decomposition
  • the layer completes the data stream detection of each subchannel; wherein the properties of the diagonal elements of the lower triangular matrix L in descending order of probability ensure the performance of the SIC technique. Therefore, in the present invention, the receiving end does not need to perform any sorting and decomposing operations, and the SIC detecting sequence which is large to the subchannel gain can be completed with a large probability, and the error propagation effect is effectively expanded.
  • the complexity of the receiving algorithm is reduced; the technical solution of the present invention reduces the operation complexity of the processing at the receiving end while effectively improving the performance of the MMO subchannel detection at the receiving end.
  • the transmission method of the technical scheme of the present invention is compared with the average BER performance of the traditional ZF QLD, ZF-SQLD, ZF OSIC detection algorithms. It can be seen from the figure that the transmission method according to the technical solution of the present invention can effectively suppress the error propagation effect in the SIC detection and improve the average bit error rate performance of the system.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Radio Transmission System (AREA)

Abstract

La présente invention se rapporte à un procédé de transmission basé sur un précodage sans livre de codes dans un système MIMO. Le procédé selon l'invention comprend les étapes suivantes : un terminal de transmission acquiert les données de canal d'un moment antérieur via la rétroaction ou la réciprocité de canaux spécifiques au système TDD, il acquiert une matrice unitaire Q et une matrice triangulaire inférieure L dont les éléments diagonaux sont agencés dans un ordre de probabilité descendant en exécutant une opération de décomposition SLQD sur les données de canal, et il accomplit ensuite le précodage pour envoyer un signal et le signal pilote au moyen de la matrice unitaire Q ; un terminal de réception exécute une estimation de canal sur le signal pilote pour lequel un précodage a été accompli, de sorte à acquérir la matrice triangulaire inférieure L dont les éléments diagonaux sont agencés dans un ordre de probabilité descendant, ceci faisant suite à l'exécution de l'opération de décomposition SLQD par le terminal de transmission ; et le terminal de réception traite ensuite le signal reçu selon la technologie SIC, de sorte à éliminer les interférences sur un signal de sous-canal dans une couche appartenant aux couches précédentes de sous-canaux. De cette manière, une détection de flux de données est accomplie pour chaque sous-canal selon le principe d'une couche après l'autre. La solution technique de la présente invention permet d'améliorer de façon significative la performance de détection de sous-canaux MIMO sur le côté du terminal de réception. Dans le même temps, la complexité opérationnelle du traitement sur le côté du terminal de réception est également réduite.
PCT/CN2011/083374 2010-12-31 2011-12-02 Procédé de transmission basé sur un précodage sans livre de codes dans un système mimo Ceased WO2012088993A1 (fr)

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CN201010624033.5 2010-12-31
CN2010106240335A CN102123114A (zh) 2010-12-31 2010-12-31 用于mimo系统中的基于非码本预编码的传输方法

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Families Citing this family (6)

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CN102123114A (zh) * 2010-12-31 2011-07-13 北京邮电大学 用于mimo系统中的基于非码本预编码的传输方法
CN102340377A (zh) * 2011-10-17 2012-02-01 中兴通讯股份有限公司 一种非线性预编码处理方法、装置和系统
CN102769510B (zh) * 2012-06-14 2016-04-13 北京邮电大学 联合非码本与码本的多用户预编码方法及装置
CN107094124B (zh) * 2016-02-18 2020-02-14 北京信威通信技术股份有限公司 一种下行多用户多天线数据传输方法、装置及系统
CN109995401B (zh) * 2017-12-29 2022-02-11 南京北冶机电设备有限公司 一种双向qr分解检测方法和装置
CN110460360B (zh) * 2018-05-08 2020-06-30 上海朗帛通信技术有限公司 一种被用于无线通信的用户设备、基站中的方法和装置

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