Research On PAPR Reduction Algorithm In SFBC MIMO-OFDM System

MIMO-OFDM (Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing) technology uses space, time, frequency diversity technique, it can obviously increase the capacity of wireless communication system in AWGN and multi-path channels. It has tremendous potential in strengthen the validity and reliability of wireless links. But the higher Peak-to-Average Power Ratio of OFDM systems can seriously worsen the performance of the MIMO-OFDM systems.The research is focused on the PAPR reduction algorithm in SFBC (Space-Frequency Blocking Coding) MIMO-OFDM system. SF-SLM (Space Frequency Selecting Mapping) and SF-PTS (Space Frequency Partial Transmit Sequence) algorithm are proposed first, these two algorithm solve the problem of how to flitting the typical algorithm-SLM and PTS in OFDM system to SFBC MIMO-OFDM system. Then the explicit analyses of the two algorithms are put forward. Then aiming at the property of SFBC coding, a novel PAPR reduction method named T-PTS(Twice PTS) algorithm are proposed, it is a further improved algorithm of SF-PTS algorithm, and RT-PTS(Reduced T-PTS) is a suboptimum method of T-PTS algorithm. T-PTS algorithm treats all transmit antennas as a whole, by dividing, rotating, and shifting the sequence twice, the method fully makes use of the character of conjugation and shifting of all the antennas'sub carriers, meanwhile reducing the complexity of calculation by using the character of IFFT.Large amounts of theoretical analysis and simulation experiment are done to do research of PAPR reduction method in SFBC MIMO-OFDM system, and a feasible algorithm in practical system is proposed at last, named RT-PTS algorithm. The simulation result proves that RT-PTS algorithm can achieve very good PAPR performance at lower complexity and less assist information.