多天线双向中继网络利用中继节点辅助两个源节点进行信息交换，具有大容量，广覆盖的优点，是4G无线通信系统的一个重要网络拓扑结构，有广泛的应用前景。本项目拟研究其两个关键点:首先，研究多天线双向中继系统的信息论基础问题，通过建立不同天线配置的多天线双向中继网络模型，分析系统的空间自由度，信道容量，及分集与复用增益的折中关系。其次，为获取系统的空间复用增益，本项目将提出新的双向MIMO物理层网络编码矩阵，它将复杂的双向MIMO信道分解为独立的PNC子信道，并考虑绿色通信需求，通过建立能够反映中继策略的能量效率函数，研究节点的能量分配，使系统在满足业务需求的前提下，能耗最小。本项目的研究内容，不仅推动了无线中继网络理论的发展，也为绿色通信的研究提供一条有效途径。

Multi-antenna two-way relay network that using the relay nodes assists two source nodes exchange their information has the advantages of large capacity and wide coverage. It is an important network topology for 4G wireless communication system, and has a wide range of application prospects. This research project intends to study the two key points: First, the information theory foundation issues of the multi-antenna two-way relay system would be studied. Through establishing the multi-antenna two-way relay network models under different antenna configurations, the spatial degrees of freedom, the capacity of the channel, and the tradeoff of diversity the multiplexing gain would be anaylzed. Secondly, in order to obtain the maximum space multiplexing gain of the system, the project will propose a new bi-directional MIMO physical-layer network coding matrix, which can decompose a complex two-way MIMO channel into several independent PNC subchannels. Futhermore, considering the requirment of green communications, we'll study the energy allocation among the communication nodes. Using a new energy-efficiency function that can reflect relay strategy, a resource allocation method that meet users' rate requirments with minimum energy consumption is proposed. The content of the project, not only to promote the development of wireless relay network theory, and also provide an effective way for green communications research.