交织多址接入系统定点Logistic交织序列生成算法

Fixed-point Logistic interleaving sequence generationalgorithm for interleave division multiple access system

交织多址接入(interleave division multiple access,IDMA)技术作为典型的非正交多址接入技术,受到学术界和产业界的广泛关注。为降低IDMA系统多用户检测过程存储空间和计算复杂度,采用双极性化的定点Logistic序列与待(解)交织序列对应相乘方式完成(解)交织;同时,为降低任意量化比特长度的定点Logistic序列生成过程时延,采用现场可编程逻辑门阵列进行生成。利用Logistic系统李雅普诺夫指数,确定处于混沌状态的定点Logistic序列量化比特长度;基于平衡度和互相关门限,确定定点Logistic序列开始位置和初值;采用查表法构建非对称基本乘法器,并采用移位相加法计算总乘法器。仿真结果表明,所提算法可以充分利用Logistic序列混沌、平衡度、相关等特性,具有较好的误码率性能。

Interleave division multiple access(IDMA)technology,as a typical non-orthogonal multiple access technology,has been widely concerned by academia and industry.In order to reduce storage space and computational complexity of the multi-user detection process of the IDMA system,a dual-polarized fixed-point Logistic sequence is multiplied with the corresponding(de-)interleaving sequence to complete the(de-)interleaving.In order to reduce the time delay in the fixed-point Logistic sequence generation process with arbitrary quantization bit accuracy,a field programmable gate array(FPGA)is used for sequence generation.Firstly,the quantization bit length of the fixed-point Logistic sequence in a chaotic state is determined by using the Lyapunov exponent of the Logistic system;then the initial value and start position of the fixed-point Logistic sequence are determined based on the equilibrium degree and cross correlation threshold;finally,the non-symmetric basic multiplier is constructed by the table look-up(LUT)method,and the total multiplier is calculated by the shift-addition method.Simulation results show that the proposed algorithm can sufficiently use the chaos,equilibrium and correlation properties of Logistic sequences and has a good bit error rate(BER)performance.