基于自适应演化算法的DS-CDMA多用户检测

提出了一种新的自适应演化算法，用来解决码分多址系统中的多用户检测问题．该算法采用最大似然判决来检测用户发送的比特序列，根据当前变异的成功概率来自适应调整子代种群规模．仿真结果表明，基于自适应演化算法的多用户检测器总能在指定的迭代次数内收敛到与最优多用户检测器相一致的结果．该算法与未采用自适应机制的进化规划相比，当用户数从10增加到20时，收敛所需的代数相应减少37．5％到47．8％．该算法的计算复杂度是与用户数相关的多项式复杂度，与最优多用户检测器的指数复杂度相比，具有较好的可行性和实用性．

Multiuser Detection for DS-CDMA Systems Using Adaptive (1+λ) Evolutionary Algorithm

An adaptive evolutionary algorithm(EA) based multiuser detector for direct sequence code division multiple access(DS-CDMA) systems is presented in this paper.The adaptive EA adopts maximum likelihood decision rule to detect the user bit sequences and adaptively adjusts its offspring population size according to the current mutation success probability.The major advantage of the adaptive EA based multiuser detector is that it obtains rather good bit error rate(BER) performance with less generations.Simulation results show the adaptive EA based multiuser detector can always converge to the optimal solution with a smaller number of generations.Compared to ecolutionary programming(EP),when user nurnber increases from 10 to 20,the corresponding convergence generation decreases from 37.5% to 47.8%.Its BER performance is close to that of the optimal multiuser detector and the computational complexity is polynomial complexity.