Iterative Multiuser Detection for Underwater Acoustic Channels
Iterative Multiuser Detection for Underwater Acoustic Channels
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DOI：
10.1109/joe.2011.2164954
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发表时间：
2011-09
影响因子：
4.1
通讯作者：
S. Aliesawi;C. Tsimenidis;B. Sharif;Martin Johnston
中科院分区：
文献类型：
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作者：
S. Aliesawi;C. Tsimenidis;B. Sharif;Martin Johnston
两种不同的同步下行链路多访问方案，Interleave-Division多元访问（IDMA）和代码分割多重访问（CDMA），用于务实的水下水下通信通道，表现出延长的多路径传播和时间可变性。提出了两个单元素DFE-IDMA和DFE-CDMA接收器，利用芯片级的自适应决策反馈均衡（DFE）和载体相跟踪以及迭代干扰取消（IC）和通道编码。描述检测算法的接收器方程是得出的，并研究了其性能并比较。为了跟踪和补偿通道效应，DFE和载体相跟踪单元是根据均方根误差（MSE）标准共同优化的，并通过与涡轮增压的估计来互换软信息，并通过迭代进行改编。处理阶段。检测是通过使用软芯片取消来删除用户之间的多元访问干扰（MAI）效应来实现检测的。使用在北海海上试验期间获得的信号的离线处理，研究并比较了拟议的接收器结构的性能。同步多源场景的结果，每个用户的有效速率为439.5 b/s，表明基于DFE的IDMA和CDMA接收器可以提供大约10-5的位表现（BER）平均信噪比和噪声比（SINR）为11 dB。实验结果还表明，这些直接自适应接收器具有更好的性能，并显着减轻与通道估计（CE）基于基于频道的IDMA和CDMA接收器相关的位误差，同时保持较低的复杂性。此外，在某些情况下，具有部分知识的接收器对来人的模式或代码仍然可以达到与具有全面知识的人相当的绩效。
Two different synchronous downlink multiple-access schemes, interleave-division multiple access (IDMA) and code-division multiple access (CDMA), are considered for pragmatic underwater communications channels exhibiting extended multipath spread and time variability. Two single-element DFE-IDMA and DFE-CDMA receivers are proposed that utilize chip-level adaptive decision feedback equalization (DFE) and carrier phase tracking along with iterative interference cancellation (IC) and channel coding. The receiver equations describing the detection algorithms are derived and their performance is investigated and compared. To track and compensate for the channel effects, the DFE and carrier phase tracking units are jointly optimized based on the mean square error (MSE) criterion and adapted iteratively by exchanging soft information in terms of log-likelihood ratio (LLR) estimates with the turbo processing stage. The detection is implemented by using soft chip cancellation to remove multiple-access interference (MAI) effects between users. The performance of the proposed receiver structures is investigated and compared in short-range shallow-water acoustic channels using offline processing of signals acquired during sea trials in the North Sea. Results for synchronous multiuser scenarios, with two and four users at an effective rate of 439.5 b/s per user, demonstrate that the proposed DFE-based IDMA and CDMA receivers can provide bit error rate (BER) performances of approximately 10-5 at an average signal-to-interference-and-noise ratio (SINR) of 11 dB . The experimental results also demonstrate that these direct adaptive receivers have better performance and significantly mitigate the bit errors associated with the channel estimation (CE)-based IDMA and CDMA receivers with Rake reception while maintaining lower complexity. Furthermore, in some cases, the receivers with partial knowledge of the interleavers' patterns or codes can still achieve performance comparable to those with full knowledge.