多码组合扩频通信中软解调解扩算法研究  

Research on Soft Demodulation and Despreading Algorithms in Parallel Combinatory Spread Spectrum

作　　者：陈盈 窦高奇[1] 王青波[1] 邓冉[1] CHEN Ying;DOU Gao-qi;WANG Qing-bo;DENG Ran(Institute of Electronic Engineering,Naval University of Engineering,Wuhan 430033,China)

机构地区：[1]海军工程大学电子工程学院,武汉430033

出　　处：《火力与指挥控制》2020年第6期13-17,共5页Fire Control & Command Control

基　　金：国防重点实验室基金(61421020405);海军工程大学科研发展基金资助项目(425317Q024)。

摘　　要：多码组合扩频通过采用多条PN序列叠加传输的方式,在相同带宽条件下相比多进制扩频可有效提高信息承载能力,然而,多条PN序列并行叠加会造成检测性能下降。从解调解扩联合处理角度,提出基于最大似然解调检测的联合解调解扩的软判决算法,该算法通过对接收组合序列进行最大似然网络图相关值路径搜索,完成解调解扩联合处理。从而既克服了硬判决解调导致的信道信息损失,又节省了常规软判决算法中相关器的数量需求。仿真结果表明:所提算法在相同误码率情况下相比硬判决算法提升约6 dB。Multi-code combined spread spectrum can effectively improve the information carrying capacity compared to M-ary spread spectrum over the same bandwidth by methods of using multiple PN sequence superposition and transmission.However,the parallel superposition of multiple PN sequences will result in a decrease in detection performance.In this paper,a soft decision algorithm based on maximum likelihood demodulation detection for joint demodulation and despreading is proposed.The algorithm performs the maximum likelihood network graph correlation value path search on the received combined sequence to complete the demodulation and despreading joint processing.Thereby,the loss of channel information caused by hard decision demodulation is overcome,and the number of correlators in the conventional soft decision algorithm is saved.The simulation results show that proposed algorithm compared with hard decision algorithm improves by 6 dB at the same bit error rate in the case of the same bit error rate.

关 键 词：多码组合扩频 软判决 解调解扩 路径搜索 

分 类 号：TN919.6[电子电信—通信与信息系统]