SLM (Selected Mapping) method of SFBC (Space Frequency Block Coding) MIMO-OFDM (Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing) 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 an SLM method for reducing the peak-to-average ratio of MIMO-OFDM systems based on SFBC. Background technique [0002] Orthogonal frequency division multiplexing technology (OFDM) is widely used in digital audio broadcasting (DAB), digital video broadcasting (DVB), wireless local area network (WLAN), and its high spectrum utilization rate, anti-multipath interference and other advantages can effectively eliminate signal interference , so it has received more and more attention. Multiple-input multiple-output (MIMO) can increase the channel transmission rate and obtain higher diversity gain or capacity gain by configuring multiple antennas on both the transmitting and receiving sides. The combination of the two technologies in wireless communication is MIMO-OFDM (Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing), in which OFDM can convert frequency-sel...

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, as described in the document "Chen, H Liang, H PAPR 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 idea of ​​the algorithm is to use different encoding methods to avoid the occurrence of symbols that may generate 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.STBC MIMO-OFDMPeak-to-Average Power Ratio Reduction by Cross-Antenna Rotation and Inversion" do not have complex multiplication operations in each iteration, and the computational complexity is reduced, but If the algorithm is directly extended to a system with more transmitting antennas, it cannot take full advantage of the additional degrees of freedom provided by adding antennas

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