A Method of Selective Mapping SLM for Space-Frequency Coded SFBC MIMO-OFDM System Based on f Matrix

Abstract

The invention discloses an SLM (Selected Mapping) method of an SFBC (Space Frequency Block Coding) MIMO-OFDM (Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing) system based on an F matrix, solving the problems of high peak-to-average power ratio and high computation complexity of SFBCMIMO-OFDM signals in the MIMO-OFDM system. An algorithm for lowering the peak-to-average ratio and the calculation complexity of the system is provided by researching the orthogonality of SFBC coding-based signals on antennas in an MIMO system. According to the SLM method of the SFBC MIMO-OFDM system based on the F matrix, the SFBC signals are processed by utilizing the F matrix of a given phase sequence; an obtained optimal phase factor is subjected to quadrature encoding and acts on the SFBC signal of each antenna; in such a way, the to-be-sent signal on each antenna can be prevented from being subjected to IFFT (Inverse Fast Fourier Transform) for multiple times; and therefore, the calculation complexity of the system is lowered. Meanwhile, by the adoption of the F matrix, the MIMO-OFDM system obtains a good peak-to-average ratio performance.

Description

technical field [0001] The invention relates to the field of mobile communication, in particular to a selective mapping (SLM) method for reducing the peak-to-average ratio of a multiple-input multiple-output-orthogonal frequency division multiplexing (MIMO-OFDM) system based on space-frequency coding (SFBC). Background technique [0002] Orthogonal Frequency Division Multiplexing (OFDM) is widely used in Digital Audio Broadcasting (DAB), Digital Video Broadcasting (DVB), and Wireless Local Area Network (WLAN). Its advantages of high spectrum utilization and anti-multipath interference can effectively eliminate signal interference. , so it has received more and more attention. Multiple-Input Multiple-Output (MIMO) can improve channel transmission rate and obtain higher diversity gain or capacity gain by configuring multiple antennas on both sides of the transceiver. The combination of the two technologies in wireless communication is MIMO-OFDM (Multiple-Input Multiple-Output...

AI Technical Summary

Problems solved by technology

[0004] For OFDM systems, techniques for reducing PAPR can be roughly divided into three categories: one is coding techniques, document "Chen, HLiang, HPAPR Reduction of OFDM Signal Using Partial Transmit Sequences and Reed-Muller Codes, IEEE Communications Letters, vol.11, no.6, pp.528-530, Sep.2007 ", the algorithm idea is to use different encoding methods to avoid the occurrence of symbols that may produce higher PAPR, but the encoding process is more complicated

The second category is signal predistortion technology, including clipping method and companding method. This technology is the simplest and most direct nonlinear method to reduce the peak-to-average ratio, but the in-band distortion and out-of-band radiation introduced by the former will seriously reduce the system performance. performance

The third category is scrambling technology, including selective mapping SLM and partial transmission sequence PTS. This technology uses different scrambling sequences to weight OFDM symbols. By setting the PAPR threshold condition, select the minimum PAPR from the sequence to be transmitted. A group is used for transmission, which significantly reduces the probability of high peak power signals, but due to the use of too many IFFTs, the computational complexity increases sharply, and the transmission of side information also causes the loss of data transmission rate

The patent "Zhang Chaoyang et al., A Peak-to-Average Ratio Control Method, Receiver and Transmitter" describes a method for reducing the PAPR of the system through the combination of linear and nonlinear methods, but the algorithm process is too complicated

Patent "CN102075222A, Jiang Tao, Li Si, Qu Daiming, a method for reducing the peak-to-average power ratio of space-frequency coded MIMO-OFDM signals", although there is no need to send sideband information, the algorithm has a large amount of calculation

The CARI and its improved algorithm proposed by the patent "CN101073217A, TANM, ZORANLZ, YEHESKELBN.STBCMIMO-OFDMPeak-to-AveragePowerRatioReduction by Cross-AntennaRotationandInversion" do not have complex multiplication operations in each iteration, and the computational complexity is reduced. However, if the algorithm is directly extended to more In systems with transmitting antennas, the additional degrees of freedom provided by adding antennas cannot be fully utilized

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