中文摘要：

水声信道传播时延大导致水声通信网中上行用户同步困难,因此需要接收端具备异步多用户检测能力。针对水声正交频分复用（OFDM）异步多用户系统提出一种基于滑动迭代的异步多用户接入方法,包括重叠截断、干扰消除、频域过采样、多用户信道估计与解码、以及干扰重构5个处理模块,并通过滑动迭代结构同时消除前向干扰和后向干扰影响。仿真结果表明,所提方法在不同异步到达时延,以及有、无信道估计误差下的误比特率均明显低于逐块解调异步接收算法。水池实验结果表明,滑动迭代异步接收算法在多径扩展18 ms、异步到达时延大于或等于循环前缀1.5倍时实现了两用户异步接入的可靠通信。

英文摘要：

Due to the large propagation delays in underwater acoustic channels, uplink synchronization is a great challenge in underwater acoustic sensor network, and thus the ability of asynchronous multiuser detection at the receiver is highly desired. A sliding iteration based asynchronous multiuser reception approach is proposed for the orthogonal frequency division multiplexing （OFDM） system, including overlapped truncation, interference cancellation, frequency- domain oversampling, multiuser channel estimation and data decoding, and interference reconstruction, which works in a sliding iteration fashion to eliminate the interference from the preceding and succeeding processing units. Simulation results show that the proposed method outperforms in terms of the bit-error-rate the block-by-block asynchronous multiuser receiver under different relative delays, and with or without channel estimation error. Pool experimental results show that the proposed approach achieves reliable two-user communications when the relative delay is no less than 1.5 times the CP duration in a multipath channel of 18 ms spreading delay.