基于信道跟踪的异步多用户OFDM系统接收机

本文针对空分多址接入OFDM系统上行链路提出了一种基于信道跟踪的异步多用户OFDM系统接收机,在每帧数据的开头设置导频符号得到初始信道估计,然后针对每一个数据符号在逐子载波的MMSE检测器、干扰抵消和信道估计之间迭代,得到最终的符号输出.仿真和分析结果表明这种接收机在保留了逐子载波处理简单结构的同时可以有效地跟踪信道.同时,用户在一定的移动速度下,异步时延越小,用户间干扰越弱,系统性能越好;帧长越短,信道跟踪能力越强.

An asynchronous multi-user OFDM receiver based on channel tracking

In this paper,an asynchronous multi-user OFDM receiver based on the channel state information(CSI) tracking is proposed for the space division multiple access(SDMA) OFDM systems.The initial values of channel estimation come from pilots,and then per-carrier MMSE detection,interference cancellation and channel re-estimation are iteratively conducted.The simulation and analysis show that the receiver can track the variation of fast fading channels effectively with a simple structure,and that when users are traveling at a fixed speed,the less asynchronous the delay is and the shorter the frame length is,the better the performance is.