面向实用物理层网络编码的基础理论与算法研究

Physical layer network coding (PNC) is a novel transmission strategy that we proposed in 2006. Currently, PNC is attracting a lot of attention from all over the world for its capability of boosting the throughput of wireless networks and approaching the capacity of two-way relay channel (TWRC). To our knowledge, most of the research on PNC were theoretical and weresed on many ideal assumptions, such as perfect synchronization, perfect channel information and high processing capability. However, these ideal assumptions can not be satisfied in real wireless systems. Therefore, it is urgent and valuable to study the praticable PNC without those ideal assumptions. This project will concentrate on the fundamental theories and algorithms for practical PNC. In particularly, we will study the encoding algorithms at the relay node for finite field PNC, and prove that the new algorithms can achieve full diversity gain and near optimal performance. After that, we will mainly discuss the decoding algorithms at the two end nodes for infinite field PNC, based on the proposed blind known interference cancellation scheme which does not need the channel information. Then,we will explore the superiorty of the new algorithms, show its significant impact on information theory. Finally, we will compare both finite and infinite field PNC in a deep way and propose an adaptive PNC by combining them together. We believe that this project will lay a solid fundation for the application of PNC in real systems.

物理层网络编码（PNC）是申请人提出来的一种全新的无线传输方案，该方案不仅可以显著提高无线网络的吞吐量，还可以逼近双向中继信道的信道容量,引起了国内外学者的广泛研究。目前有关PNC的研究主要集中在理论领域，且通常假设节点拥有精确同步、完全信道信息、无限处理能力等。然而，这些理想假设在实际系统中却不能实现，非理想条件下的高效PNC方案是本领域亟需研究的课题。 本项目主要研究实际条件下的高性能PNC算法及其理论性能。具体而言：针对有限域PNC，本项目主要研究中继节点在单/多天线情况的编码算法，证明新算法可以得到全部分集增益、逼近理想条件下的性能；针对无限域PNC，本项目主要研究两端节点的的解码方法，提出无需信道信息的盲已知干扰消除算法，阐明新算法优秀的性能并揭示其对信息理论的重要意义；之后，将对两类PNC方案进行深入比较与自适应融合，以便更全面地理解双向中继信道，为PNC的应用建立理论基础。

在自然科学基金项目“面向实用物理层网络编码的基础理论与算法研究”的资助下，完成了申请书的主要研究内容，取得了一系列的重要研究成果。主要研究成果包括（1）首次建立了已知干扰信道的信道容量，指出利用盲已知干扰消除算法（此算法仅需要符号级的时间同步和频率同步）可以逼近此信道容量；（2）对不可信中继信道，首次提出了取模-转发的物理层网络编码策略，在不需要严格时间同步与频率同步的情况可以逼近不可信中继信道的安全容量；（3）提出了多天线信道采样的物理层网络编码策略，降低了系统的同步要求，达到了理论最大信道容量。在项目完成过程中，一共发表IEEE Transaction论文13篇，其中包括影响因子最高的通信技术杂志IEEE JSAC3篇，其他SCI期刊论文9篇，国际会议论文11篇。申请发明专利6项，举办国际学术workshop两次，招收博士后三名，毕业博士生一名，在读博士生3名，毕业硕士研究生11名，在读硕士研究生8名。项目负责人张胜利晋升为教授，项目成员代明军晋升为副教授。张胜利还应邀担任IEEE Transaction on Vehicle Technology的编委会成员，成为IEEE高级会员。