一种改进的喷泉多选择序列峰均比降低算法

针对非连续正交频分复用(NC_OFDM)系统具有边带功率(Sidelobe power)大及峰均比(PAPR)高等问题,提出一种基于喷泉编码(Fountain code)的改进算法,同时考虑认知无线电环境下NC_OFDM系统旁瓣干扰及峰均联合优化.采用喷泉多选择序列算法,通过喷泉编码及序列映射的思想,降低边带功率及系统PAPR.仿真表明,喷泉编码改进算法能有效减少NC_OFDM系统中感知用户对于授权用户(licensed user)的干扰,通过喷泉编码设定目标PAPR将NC_OFDM系统PAPR控制在合理范围内,从而有效解决NC_OFDM信号放大失真问题,提升系统整体误比特率性能.

An Improved Fountain Multi-choice Sequence Algorithm for Peak-to-Average Power Ratio Reduction

Non-continuous orthogonal frequency division multiplexing (NC_OFDM) has large sidelobe power and high peak-to-average power ratio (PAPR).In this paper, an improved algorithm with Fountain coding was proposed, in which the sidelobe interference in NC-OFDM system and high peak to average ratio were both taken into consideration in the joint optimization algorithm under the circumstance of cognitive radio system.Fountain multi-choice sequence algorithm, by the ideal of Fountain coding and sequence mapping, was adopted for sidelobe suppression and PAPR reduction.The simulation results show that the improved algorithm can significantly reduce the band interference to licensed user (LUs) and make the system PAPR less than target PAPR, so as to solve the problem of NC_OFDM signal distortion caused by power amplifier and eventually enhance the performance of the bit error rate effectively.