降低OFDM系统峰均比的SI-PTS算法

PAPR reduction in OFDM using a methodology:SI-PTS

针对正交频分复用系统的高峰均功率比问题,在传统子块交织和部分传输序列(partial transmit sequence,PTS)算法的改进基础上提出了联合SI-PTS算法。算法中提出了1个新的子块交织方案,其中的每个子块相互交织。另外,还提出了1个新的相位因子优化方案,方案中的相位因子只有两相序列,迭代次数等于子数据块的数目,极大地降低了计算复杂度。所提算法基于传统PTS算法,利用新的优化方案优化部分传输序列,并结合新的子块交织技术,打乱原正交频分复用(orthogonal frequency division multiplexing,OFDM)信号序列,以降低其相关性,并进而降低OFDM系统的PAPR值。仿真结果表明,SI-PTS算法与传统PTS、SLM算法相比,能有效地改善OFDM系统的PAPR性能,并在保持系统误码率性能的前提下,有效地降低计算复杂度;SI-PTS算法对PAPR的抑制能力随着子载波数目的增加而下降,随着分组数的增加而提高。

To tackle high Peak-to-Average Power Ratio problem in orthogonal frequency division multiplexing, a new algorithm subblocks interleaving-partial transmit sequence （SI-PTS） is proposed, which is based on the combination of subblocks interlea-ving and PTS techniques. In this technique, a new subblocks interleaver is proposed, in which each subblock is interleaved with the others. In addition, a new phase factor optimisation scheme is introduced, which has only two phase sequences, The number of iterations is equal to the number of subblocks,which greatly reduce the computational complexity. The proposed algorithm is based on the traditional PTS algorithm, using the new optimization scheme to optimize part of the transmission sequence, combi-ning with the new subblocks interleaving technology, and disrupting the original OFDM signal sequence to reduce its relevance, thus reducing the PAPR of the OFDM system. The simulation results show that the SI-PTS algorithm can effectively improve the PAPR performance of the OFDM system and can effectively reduce the computational complexity without degrading its BER per-formance. The performance of PAPR by SI-PTS algorithm decreases with the increase of the number of subcarriers？ and increases with the number of groups.