两跳MIMO级联中继网络自由度研究

Degree of freedom for the two-hop cascaded MIMO relay networks

未来移动通信系统的发展和演进涉及的两个基本方面是提高系统的吞吐量和覆盖率,为了实现这两个目标,多输入多输出(MIMO)中继技术成为主流的解决办法。因此模拟现实情况,使用了TDD模式下的由源节点、中继节点、目的节点组成的两跳MIMO级联中继网络模型。采用改进的最大流-最小割定理方法得到中继网络的该模型自由度的上界;采用解码-转发与迫零信号处理得到了该模型自由度的下界。最后得到各对应情况下自由度下界与上界相等的结论,且其自由度均为天线数的函数。

The MIMO relay networks will be used as a main solution to improve the throughput and the coverage of a network in the future. In order to simulate the real situation, we consider a two-hop cascaded MIMO relay network composed of a source node, a relay node and a destination node which works under time -division-duplex（TDD） mode. The upper bound is obtained by using the modified max-flow rain-cut theorem and the lower bound is gotten by using decode-forward and zero-forcing approach. We can conclude that the upper bound of the DoF equals to the lower bound of the DoF through some demonstration and we also get a conclusion that the DoF is a function of antennas.