SLM method for lowering peak-to-average power ratio of SFBC MIMO-OFDM system

Abstract

The invention discloses an SLM method for lowering the peak-to-average power ratio of an SFBC MIMO-OFDM system. Information source bits of each antenna pass through a baseband modulation unit and a series-parallel-connection conversion unit, are subjected to different phase rotation, and then are subjected to IFFT modulation to obtain time domain signals, time domain odd-even signals are obtained through the circulation shift property of time domain signals of an FFT, and the time domain odd-even signals are subjected to different lengths of time domain circulation shifts and then subjected to time domain equivalent SFBC encoding to obtain alternative sequence pairs with different PAPRs. On the basis of a traditional SLM algorithm, more alternative sequence sets with different PAPRs can be obtained only through circulation shift and phase rotation of the time domain signals, and the PAPR inhibition performance is improved. Meanwhile, a receiving end recovers the odd-even signals, circulation shift factors and phase rotation factors by comparing the distance between a reverse rotation sequence and a nearest signal constellation point, and sideband secondary information does not need to be transmitted.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, in particular to an SLM method for reducing the peak-to-average power ratio of an SFBC MIMO-OFDM system. Background technique [0002] As we all know, the multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM for short) system obtains diversity gain by using frequency, time and different antennas, which can effectively resist multipath and noise in wireless communication, and become the future mobile One of the main candidate technologies for multimedia communication. [0003] The MIMO-OFDM signal is a multi-carrier modulation signal, and one of its main disadvantages is that the signal peak power to average power ratio (PAPR for short) is relatively high. At present, a mainstream method for reduced space-frequency block coding (SFBC) MIMO-OFDM system is selective mapping method (abbreviated as SLM method). Without loss of generality, a two transmit...

AI Technical Summary

Problems solved by technology

In the SFBC MIMO-OFDM system, one disadvantage of the traditional SLM method is that in order to obtain better PAPR suppression performance, it is usually necessary to select a sequence pair with the smallest PAPR from multiple candidate pairs for transmission, and each candidate signal Both need to be obtained by IFFT modulation, and the computational complexity of the algorithm is relatively high

Another shortcoming of the traditional SLM method is that in order for the system to restore the original signal at the receiving end, the transmitting end needs to transmit the sideband side information of the phase factor used, and the transmission of the sideband side information reduces the spectrum utilization efficiency of the system

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