双选择性信道中OFDM信号的均衡

OFDM Signal′s Equalization Over Double-Selective Channels

正交频分复用(OFDM)技术是一种多载波调制方式,由于他易于实现并且能够有效对抗频率选择性衰落,因此受到了人们极大的重视。他将数据在相互正交的子载波上并行发送,同时在数据的前端引入循环前缀,可以有效地对抗频率选择性信道,消除符号间的干扰,实现数据的高速传输。但是当他在频率选择性和时间选择性信道条件下,也就是双选择性信道条件传输时,子载波之间的正交性会遭到破坏。文章讨论了双选择性信道条件下,在时域采用自适应均衡器来消除信道时变带来的载波间干扰,保证各个子载波的正交性。仿真结果表明,信号可以被正确的恢复。

Orthogonal Frequency Division Multiplexing （OFDM） is a multicarrier modulation （MCM） technology. It has attracted a lot of attention due to its simple implementation and robustness against frequency-selective channels. The data was transmitted in parallel using different subcarriers which are orthogonal to each other. And a cyclic prefix （CP） is added at the start of each symbol, so it can reject the frequency-selective channels effectively. But when the signal is transmitted in a frequency-selective and time-selective channel, i.e. double-selective channel, the channel was varying with time; the orthogonality was destroyed between subcarriers. In this paper, we discussed using time domain equalization to eliminate the effect of varying channel in time domain. The simulation result shows that the signal can be correctly recovered.