| 摘要: |
| 传统稀疏码分多址（Sparse Code Division Multiple Access,SCMA）系统在固定时频资源块（Resource Block,RB）上传输信息，系统性能易受到信道污染（外在干扰和信道衰落）的影响。为了解决这一问题，提出一种基于资源块间跳频（Frequency Hopping,FH）的SCMA系统（FH-SCMA系统）。借助跳频技术实现动态SCMA码字复用，使得各用户能够均匀、随机地使用所有资源块。同时，基于素数序列设计了一种动态码字正交复用的跳频策略（跳频码），提升了FH-SCMA系统容量以及抗干扰能力。该系统接收端采用对数域消息传递（MAX-log-MPA）多用户检测算法，推导了该FH-SCMA系统的理论误码率上界。对比传统的SCMA系统，该资源块间FH-SCMA系统能均匀化资源块被污染对用户性能的影响，使得每个用户的传输误码率达到可接受的程度;相比传统SCMA系统和采用完全随机跳频策略的FH-SCMA系统（干扰时频资源占比η=25%时），设计的跳频策略及FH-SCMA系统在误码平层处分别获得4 dB和8 dB的信噪比增益。 |
| 关键词: SCMA系统 资源块跳变 高可靠传输 抗干扰设计 |
| DOI：10.20079/j.issn.1001-893x.230602004 |
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| 基金项目:四川省重点实验室开放式基金资助项目（2023-0529-04-02）；四川省科技计划资助项目（2023NSFSC0480）；抗干扰国家重点实验室开放基金项目（2022-JCJQ-LB-079） |
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| Design and Analysis of a Reliable SCMA System Based on Inter-RBs Frequency Hopping |
| ZENG Qi,YANG Kun,FANG Ke,HAO Lihong,NIU Xianhua,ZHONG Jun,LIU Xing |
| (1.College of Electrical Engineering,Sichuan University,Chengdu 610040,China;2.Southwest China Institute of Electronic Technology,Chengdu 610036,China;3.School of Computer and Software Engineering,Xihua University,Chengdu 610039,China) |
| Abstract: |
| The prototypical sparse code division multiple access(SCMA) system always transmits the non-zero code-words over the fixed resource blocks (RBs),thus likely suffering from severe performance degradation due to the contaminated RBs (jamming attacks or channel fading).For this problem,an improved SCMA system based on inter-RBs hopping is proposed.With the help of the frequency hopping (FH) technology,dynamic code word multiplexing is realized,which enables users to use all RBs uniformly and randomly.To implement the optimal inter-RBs FH-SCMA,a pseudo-random hopping strategy is designed via prime code and interleave ring operations.To reduce the complexity,a logarithmic domain messaging multi-user detection algorithm (MAX-log-MPA) is used at the receiver.The theoretical up-bound of bit error rate of the proposed FH-SCMA system is derived.Compared with the traditional SCMA system,the proposed system can average the effect of contaminated RBs on BER performance,and obtain signal-to-noise ratio gains of 4 dB and 8 dB at the error-floor under the ratio of jammed time-frequency resources η=25%. |
| Key words: SCMA system inter-RBs hopping reliable transmission anti-jamming design |
