Noncoherent Relaying in Energy Harvesting Communication Systems
Noncoherent Relaying in Energy Harvesting Communication Systems
复制标题
能量收集通信系统中的非相干中继
DOI：
10.1109/twc.2015.2462838
复制
发表时间：
2015-12-01
影响因子：
10.4
通讯作者：
Kim, Dong In
中科院分区：
文献类型：
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作者：
Liu, Peng;Gazor, Saeed;Kim, Dong In
在能量收集（EH）中继网络中，相干通信需要准确估计/跟踪瞬时信道状态信息（CSI），这会消耗额外的功率。作为一种补救措施，我们提出了两个非相干EH中继协议的基础上放大转发（AF）中继，即功率分裂非相干AF（PS-NcAF）和时间切换非相干AF（TS-NcAF），这不需要任何瞬时CSI。我们开发了一个非相干的框架，同时无线信息和电力传输（SWIPT），拥抱PS-NcAF和TS-NcAF在一个统一的形式。对于任意的M进制非相干频移键控（FSK）和差分相移键控（DPSK），我们得到最大似然检测器（MLD）的PS-NcAF和TS-NcAF在一个统一的形式，其中涉及积分评价，但作为最佳性能基准。为了避免昂贵的积分计算，我们提出了一个封闭形式的检测器使用高斯-勒让德近似，它实现了几乎相同的性能MLD，但在大大降低复杂性。这些基于EH的非相干检测器在瑞利衰落中实现全分集。数值结果表明，我们提出的PS-NcAF和TS-NcAF可以优于传统的电网供电的继电器系统在相同的总功率约束。得到了对实际SWIPT中继系统设计有用的各种见解。有趣的是，PS-NcAF在单中继情况下优于TS-NcAF，而TS-NcAF在多中继情况下优于PS-NcAF。
In energy harvesting (EH) relay networks, the coherent communication requires accurate estimation/tracking of the instantaneous channel state information (CSI) which consumes extra power. As a remedy, we propose two noncoherent EH relaying protocols based on the amplify-and-forward (AF) relaying, namely, power splitting noncoherent AF (PS-NcAF) and time switching noncoherent AF (TS-NcAF), which do not require any instantaneous CSI. We develop a noncoherent framework of simultaneous wireless information and power transfer (SWIPT), embracing PS-NcAF and TS-NcAF in a unified form. For arbitrary M-ary noncoherent frequency-shift keying (FSK) and differential phase-shift keying (DPSK), we derive maximum-likelihood detectors (MLDs) for PS-NcAF and TS-NcAF in a unified form, which involves integral evaluations yet serves as the optimum performance benchmark. To avoid expensive integral computations, we propose a closed-form detector using the Gauss-Legendre approximation, which achieves almost identical performance as the MLD but at substantially lower complexity. These EH-based noncoherent detectors achieve full diversity in Rayleigh fading. Numerical results demonstrate that our proposed PS-NcAF and TS-NcAF may outperform the conventional grid-powered relay system under the same total power constraint. Various insights which are useful for the design of practical SWIPT relaying systems are obtained. Interestingly, PS-NcAF outperforms TS-NcAF in the single-relay case, whereas TS-NcAF outperforms PS-NcAF in the multi-relay case.