Asynchronous Multiuser Reception for OFDM in Underwater Acoustic Communications
Asynchronous Multiuser Reception for OFDM in Underwater Acoustic Communications
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DOI：
10.1109/twc.2013.011713.120075
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发表时间：
2013-01
影响因子：
10.4
通讯作者：
Zhaohui Wang;Shengli Zhou;J. Catipovic;Peter Willett
中科院分区：
文献类型：
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作者：
Zhaohui Wang;Shengli Zhou;J. Catipovic;Peter Willett
近年来，点到点水声通信技术取得了显著的进展，人们对多用户通信的应用也越来越感兴趣，而多用户通信的异步特性对多用户通信提出了巨大的挑战。提出了一种适用于水声信道的正交频分复用（OFDM）传输的时间异步多用户接收方法。接收到的数据突发被分段并以重叠的方式分配给多个处理单元，其中处理单元的长度取决于OFDM块级上用户之间的最大复用。采用干扰消除来减少重叠处理单元之间的块间干扰。在每个处理单元内，来自多个用户的残留块间干扰被聚合为可以被参数化的一个外部干扰。多用户信道估计，数据检测和干扰缓解，然后进行迭代的方式。仿真和仿真实验结果表明，该接收机在时不变和时变环境下均具有多用户信号互扰的鲁棒性。研究表明，接收机解码性能随着信道时变和用户间最大相对时延的增加而下降。
Recently significant progress has been made on point-to-point underwater acoustic communications, and the interest has grown on the application of those techniques in multiuser communication settings, where the asynchronous nature of multiuser communication poses a grand challenge. This paper develops a time-asynchronous multiuser reception approach for orthogonal frequency-division multiplexing (OFDM) transmissions in underwater acoustic channels. The received data burst is segmented and apportioned to multiple processing units in an overlapped fashion, where the length of the processing unit depends on the maximum asynchronism among users on the OFDM block level. Interference cancellation is adopted to reduce the interblock interference between overlapped processing units. Within each processing unit, the residual inter-block interference from multiple users is aggregated as one external interference which can be parameterized. Multiuser channel estimation, data detection, and interference mitigation are then carried out in an iterative fashion. Simulation and emulated experimental results demonstrate the robustness of the proposed receiver with signal asynchronism among multiple users in both time-invariant and time-varying environments. It is observed that the receiver decoding performance degrades as the channel time variation and the maximum relative delay among users increase.