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Method and system for reducing codebook search-based precoding feedback bits of MIMO-OFDM system

A MIMO-OFDM, feedback bit technology, applied in the field of precoding methods and devices, can solve the problems of reducing the number of feedback bits, the amount of feedback information is huge, and narrowing the search range of a codebook, and achieves the effect of good flexibility

Inactive Publication Date: 2007-09-19
SHANGHAI JIAO TONG UNIV +1
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Problems solved by technology

[0004] ① When the channel state information is known at the receiving end, perform singular value (SVD) decomposition on the MIMO channel matrix, and use the obtained singular value vector to precode the signal. This method is theoretically able to obtain optimal performance. But to completely feed back the calculated singular value vector to the transmitter, the amount of feedback information is quite huge
These two methods both use the correlation of the codebook vectors. The subspace search method essentially narrows the scope of the codebook search and reduces the number of feedback bits, but compared with method ②, the system performance is reduced. The interpolation method uses the search Several precoding codebook vectors obtained from the complete codebook are calculated to obtain other vectors, which improves the system performance of the complete codebook search precoding, but increases the computational complexity of the system

Method used

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  • Method and system for reducing codebook search-based precoding feedback bits of MIMO-OFDM system
  • Method and system for reducing codebook search-based precoding feedback bits of MIMO-OFDM system

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Embodiment 1

[0075]This embodiment is based on the aforementioned multipath Rayleigh channel model. First, assume that the channel state is quasi-static, that is, the channel state is unchanged during the transmission of a data packet. The data used in this case contains 1920 data bits. After symbol mapping and QPSK modulation, a data packet containing 960 symbols is generated. Assuming that the channel state information has been obtained at the receiving end, the feedback generation unit completes singular value decomposition, pole search, codebook search, sub-channel grouping, sub-codebook generation, sub-codebook search, and formation of precoding codebook sequence numbers according to the channel state information. Feedback information bits and other processes. In this embodiment, one bit is used to generate sub-codebooks, that is, each sub-codebook contains 2 codebook vectors. The precoding codebook sequence number feedback information bits arrive at the transmitter via the feedback chann...

Embodiment 2

[0078] This embodiment is based on the aforementioned 3GPP spatial channel model. This channel model is a fast fading channel model relative to the above-mentioned multipath Rayleigh channel model. Therefore, this embodiment can verify the performance of the present invention under fast fading channel conditions. The specific implementation process of this embodiment is the same as that of the first embodiment. The bit error rate performance curve under the 3GPP spatial channel model shown in Fig. 8 and the feedback bit number comparison curve shown in Fig. 9 show that under the condition of the 3GPP spatial channel model, the present invention achieves a reduction in the number of feedback bits by about 32 Slightly better than the bit error rate performance of the subspace search algorithm that uses 2 bits to generate the sub-codebook; when the number of feedback bits is reduced by 281 to 4 times, the bit error rate performance is only 0.5 compared to the case of the full search ...

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Abstract

Provided is a MIMO-OFDM system codebook search based reducing procode feedback information bit number method and device which is used in the air interface communication between users and the base station. The users include the channel state information acquisition unit and a channel variation tracing unit. According to the channel state information, the corresponding largest singular values of MIMO channel matrix are extracted from each OFDM sub channel and according to the sequence of OFDM sub channel, the largest singular values can be viewed as points on a smooth curve and the pole can be found. The codebook search unit searches the complete codebook to the sub channel corresponding to the pole and obtains the corresponding complete codebook procode vector serial number. The sub channeles which ar not corresponded to the pole are divided into a number of groups according to the sequence of OFDM channel, and the construction and searching methods of sub codebook are used to obtain the procode codebook vector sub codebook serial number for each group of sub channels which are not corresponded to the pole. The feedback information integration unit feedbacks the series of codebook vector serial number information to the transmitting end.

Description

Technical field [0001] The present invention relates to a precoding method and device, in particular to a method and device for MIMO-OFDM system to reduce the number of precoding feedback bits based on codebook search. Used in the field of wireless transmission technology. Background technique [0002] Using multiple antennas on the transmitter and receiver constitutes a multiple-input multiple-output (MIMO) transmission model. This transmission method can enhance the reliability of wireless connections and increase the capacity of wireless communication systems. In a disturbance-rich wireless environment, for a system with MT transmit antennas and MR receive antennas, the contribution of MIMO transmission to the increase in channel capacity is linearly related to the relatively small number of transmit antennas and receive antennas. . For broadband communications, Orthogonal Frequency Division Multiplexing (OFDM) technology divides the frequency selective channel into a set of p...

Claims

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Application Information

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IPC IPC(8): H04B7/08H04B1/707H04L27/26H04L25/03
CPCH04B7/0417H04B7/0639
Inventor 杨博佘峰罗汉文刘仁茂颜重光
Owner SHANGHAI JIAO TONG UNIV
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