Minimum Symbol-Error Rate Based Adaptive Decision Feedback Equalizer in Underwater Acoustic Channels
Minimum Symbol-Error Rate Based Adaptive Decision Feedback Equalizer in Underwater Acoustic Channels
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水下声学通道中基于最小误码率的自适应判决反馈均衡器
DOI：
10.1109/access.2017.2772302
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发表时间：
2017
期刊：
影响因子：
3.9
通讯作者：
Zheng BX
中科院分区：
文献类型：
--
作者：
Chen;Fangjiong;Lin;Shaoe;Zheng;Beixiong;Li;Qiang;Wen;Miaowen;Liu;Yun;Ji;Fei;Chen Fangjiong;Lin Shaoe;Zheng Beixiong;Li Qiang;Wen Miaowen;Liu Yun;Ji Fei;Zheng BX
自适应线性均衡器是一种简单而有效的自适应信道衰落补偿技术，其均衡系数可根据信道冲激响应进行调整。然而，传统的自适应线性均衡器的性能下降，收敛速度慢，在水声信道的大延迟扩展。为了解决这个问题，在本文中，我们提出了一种新的自适应判决反馈均衡器（DFE）的最小符号错误率（MSER）标准的基础上。具体地，通过考虑逐个样本的自适应，该问题首先被公式化为在最新的自适应将为当前和过去的符号提供正确检测的约束下，最小化两个连续自适应之间的范数。然后，我们解决了优化问题，通过使用拉格朗日乘子法获得自适应DFE，最大限度地减少了序列符号检测误差，具有快速收敛速度。仿真结果表明，所提出的基于MSER的自适应均衡器在收敛速度和稳态性能方面明显优于现有的均衡器，用于水声信道。
Adaptive linear equalizer, whose coefficients are designed to be adjustable to the channel impulse response, has emerged as a simple and efficient technique to adaptively compensate for the channel fading. However, conventional adaptive linear equalizers suffer from performance degradation and slow convergence in the underwater acoustic channel with large delay spread. To solve this problem, in this paper, we propose a novel adaptive decision-feedback equalizer (DFE) based on the minimum symbol-error rate (MSER) criterion. Specifically, by taking the sample-by-sample adaptation into account, the problem is first formulated as minimizing the norm between two consecutive adaptations under the constraint that the latest adaptation will provide correct detection for both the current and past symbols. Then we solve the optimization problem by using the Lagrange multiplier method to obtain the adaptive DFE that minimizes the sequential symbol detection error with a fast convergence rate. Simulation results show that the proposed MSER-based adaptive DFE significantly outperforms the existing equalizers in terms of convergence speed and steady-state performance for underwater acoustic channels.