On the study of network coding with diversity
On the study of network coding with diversity
复制标题
DOI：
10.1109/twc.2009.07051022
复制
发表时间：
2009-03
影响因子：
10.4
通讯作者：
Z. Ding;K. Leung;D. Goeckel;D. Towsley
中科院分区：
文献类型：
--
作者：
Z. Ding;K. Leung;D. Goeckel;D. Towsley
最近提出的物理层网络编码（PNC）已被证明有希望显着提高无线网络的吞吐量，其链路可以建模为加性白色高斯噪声（AWGN）信道。然而，扩展到多径信道是有问题的，因为该技术将需要在每个发射机处进行幅度和相位补偿。相位补偿需要精确的分布式相位跟踪，而所需的幅度补偿甚至更麻烦，因为它导致即使在存在完美信道估计的情况下也不产生分集的低效系统。在这里，一个系统，避免这些限制是通过达到一个更高的层次，在网络层次结构和执行分布式中继选择与认知的PNC技术，我们将采用在物理层。由于所得到的方案将实现一种形式的选择多样性，我们称之为ldquetwork编码与diversityrdquo（NCD）。为了便于性能评估，两个信息理论的指标，中断和遍历容量，进行了研究。我们的分析和仿真结果表明，该协议实现了更强大的性能和更高的系统吞吐量比同类计划。最后，将所提出的网络编码方法推广到协作多址信道中，得到了一种新的协作协议，与现有的传输方案相比，该协议具有更大的中断和遍历容量。
Recently proposed physical-layer network coding (PNC) has demonstrated the promise to significantly improve the throughput of wireless networks whose links can be modeled as additive white Gaussian noise (AWGN) channels. However, the extension to multipath channels is problematic, since the technique would then require both amplitude and phase compensation at each transmitter. Phase compensation requires accurate distributed phase tracking, whereas the required amplitude compensation is even more troubling, as it leads to an inefficient system that yields no diversity even in the presence of perfect channel estimates. Here, a system that avoids these limitations is obtained by reaching up one level higher in the network hierarchy and performing distributed relay selection with cognizance of the PNC technique that we will employ at the physical layer. Since the resulting scheme will achieve a form of selection diversity, we term it ldquonetwork coding with diversityrdquo (NCD). To facilitate performance evaluation, two information-theoretic metrics, the outage and ergodic capacity, are studied. Our analytical and simulation results show that the proposed protocol achieves more robust performance and higher system throughput than comparable schemes. Finally, the proposed network coding is extended to the context of cooperative multiple access channels, which yields a new cooperative protocol with larger outage and ergodic capacity compared with existing transmission schemes.