Abstract: To suppress multiple access interference in MC-CDMA system，an algorithm based on adaptive parallel subgradient projection has been proposed.Stochastic property convex set which contains the optimal interference suppression filter coefficients is established by the receiving signal model firstly.Then parallel subgradient projection is adopted to convert projection onto convex sets to projection into multiple closed halfspaces.Finally，the updated interference suppression filter coefficients vector is projected onto the constrained set.Theoretical analysis and simulation results conclude that this algorithm has fast convergence，steady interference suppression performance，and exhibits lower bit error rate and higher robustness in different noise intensity.

Key words: MC-CDMA system, adaptive parallel subgradient projection, multiple access interference suppression

摘要： 为了抑制多载波码分多址（MC-CDMA）系统中的多址干扰，提出了一种基于自适应并行次梯度投影的多址干扰抑制算法。它首先根据接收端信号模型建立包含最优干扰抑制滤波器系数并具有随机属性的凸集，然后运用并行次梯度投影的思想将对该凸集的投影转化为对多个闭合半平面的投影，最后将更新后的干扰抑制滤波器系数矢量投影到限定集合上。理论分析和仿真结果表明，该算法具有快速收敛性和稳定的干扰抑制性能，在不同的噪声强度下都具有较低的误码率和较高的鲁棒性。

关键词: MC-CDMA系统, 自适应并行次梯度投影, 多址干扰抑制