水声正交频分复用异步多用户接入方法  

Asynchronous multiuser reception for underwater acoustic orthogonal frequency division multiplexing communications

作　　者：马璐[1,2] 刘凇佐[1,2] 乔钢[1,2] 李雪[1,2] 

机构地区：[1]哈尔滨工程大学水声技术重点实验室,哈尔滨150001 [2]哈尔滨工程大学水声工程学院,哈尔滨150001

出　　处：《声学学报》2017年第4期436-444,共9页Acta Acustica

基　　金：国家自然科学基金重点项目(61431004);国家自然科学基金面上项目(11274079);国家自然科学基金青年基金项目(61601136;61401114;61601137;61601138)资助

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。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.

关 键 词：正交频分复用 用户接入 信道估计误差 水声通信 水听器 多用户检测 循环前缀 水声信道 干扰消除 多用户信道 

分 类 号：TN929.3[电子电信—通信与信息系统]