一种降低OFDM信号峰均比的低复杂度双层搜索算法

摘要

The traditional partial transmit sequences (PTS) algorithm for Peak to Average Power Ratio (PAPR) reduction of OFDM signals has a problem that when the length of the phase rotation factor increase,the search of the factor will brings a lot of complexity. In order to reduce the PAPR more effectively.The paper proposed a novel low complexity search algorithm for PAPR reduction.The algorithm applies the traditional Hamming distance algorithm into the Dual Layered Phase Sequencing search algorithm,uses different search method in each layer according to the length of phase rotation factor.The simulation result shows that the improved algorithm reduces PAPR about 0.1dB based on the traditional method when they use the same search time.The decline become more obviously as the length of the phase rotation factor increase. In addition ,the algorithm is more flexible than the original method in the tradeoff of the system performance and search times.%在OFDM峰均比抑制技术中,采用传统的PTS算法得到的相位旋转因子随着长度的增加,存在搜索代价过高的问题,从而影响了系统的性能.为有效降低系统的峰均比,同时避免过多的搜索代价,设计了一种新的峰均比抑制算法.与传统算法相比较,该算法将汉明距离的概念应用到传统双层搜索算法中,针对不同的相位旋转因子长度,在每一层进行不同策略的搜索,得到不同的改进方案.仿真结果表明,在搜索次数相近的情况下,该算法相较传统算法能将峰均比在原有基础上再降低0.1dB左右,而且随着相位旋转因子长度的增加,效果更加明显.同时,该算法在系统性能与搜索次数上的平衡相对传统算法也更为灵活.