Nonlinear Equalization Approaches for Physical Layer Network Coding
Nonlinear Equalization Approaches for Physical Layer Network Coding
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DOI：
10.1109/twc.2016.2630694
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发表时间：
2017-02
影响因子：
10.4
通讯作者：
A. Schmidt;R. Schober;W. Gerstacker
中科院分区：
文献类型：
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作者：
A. Schmidt;R. Schober;W. Gerstacker
我们考虑一个双向中继系统采用物理层网络编码信道遭受频率选择性衰落。我们研究了判决反馈均衡（DFE），一种基于延迟判决反馈序列估计（DDFSE）的技术，以及Tomlinson-Harashima预编码（THP）方法，用于减轻信道引入的失真。对于DFE，我们引入发送滤波方案，产生相同的整体源到中继信道冲激响应的两个源节点，同时实现最大的信号-噪声比均衡后的迫零和最小均方误差标准，分别。所提倡的DDFSE方法还依赖于源节点处的发送滤波。对于THP方案，我们推导出最佳的预编码滤波器，保证了无符号间干扰的源到中继传输。为了获得一个双向中继系统，它使用相同的均衡技术在两个传输方向，我们设计了一个基于THP的折衷预编码方案的中继到目的地的传输。所提出的技术的性能进行了比较，与基准计划与简单的过滤/预编码，其中相同的整体源中继信道脉冲响应执行直接的，但次优的选择发送滤波器。我们的研究结果表明，开发的计划，使显着的收益相比，基准计划。
We consider a two-way relaying system employing physical layer network coding in channels suffering from frequency-selective fading. We study decision-feedback equalization (DFE), a technique based on delayed decision-feedback sequence estimation (DDFSE), and Tomlinson-Harashima precoding (THP) approaches for mitigating the distortions introduced by the channel. For DFE, we introduce transmit filtering schemes that generate identical overall source-to-relay channel impulse responses for both source nodes, while achieving the maximum signal-to-noise ratio after equalization for the zero-forcing and the minimum mean-squared error criterion, respectively. The advocated DDFSE approach also relies on transmit filtering at the source nodes. For the THP scheme, we derive the optimal precoding filters that guarantee an intersymbol interference free source-to-relay transmission. In order to obtain a two-way relaying system, which uses the same equalization techniques in both transmission directions, we design a THP-based compromise precoding scheme for the relay-to-destination transmission. The performance of the proposed techniques is compared with that of benchmark schemes with simpler filtering/precoding, where identical overall source-to-relay channel impulse responses are enforced by straightforward but suboptimum choices for the transmit filters. Our results reveal that the developed schemes enable significant gains compared with the benchmark schemes.