基于分布式空时干扰对齐的MIMO干扰信道自由度研究

摘要

In the context of K-user MIMO interference channel (IC),achievable degrees of freedom (DoF) were investigated with distributed space-time interference alignment (DSTIA).By precoding with distributed current and outdated channel state information at the transmitters (CSIT),new tradeoff regions between achievable DoF and CSI feedback delay/frequency were achieved for MISO system.The impact of the number of transmit antennas on achievable DoF in the MISO system was analyzed,revealing that DoF results approach to the outer bound as the number of transmit antennas increases.Further,the impact of the number of receive antennas on achievable DoF was characterized,deriving the range of CSI feedback delay that preserves achievable DoF in the MIMO system.Theoretical and numerical analyses show that,the proposed DSTIA scheme can achieve better sum-DoFs by eliminating inter-user interference perfectly,tighten the gap between achievable DoF and outer bound,as well as improve the achievable rate of the system.%针对K个用户MIMO干扰信道(IC),研究基于分布式空时干扰对齐(DSTIA)的信道可达自由度.利用分布式当前和过期发射端信道状态信息(CSIT)设计预编码,分别给出MISO系统可达自由度关于CSI反馈时延和反馈频率的折中域;分析发射端天线数对MISO系统可达自由度的影响,导出逼近系统自由度外界的条件.进一步研究MIMO系统接收端天线数对系统自由度的影响,给出保持系统可达自由度的CSI反馈时延范围.理论和数值分析表明,所提DSTIA方案能充分消除用户间干扰,获得更高的自由度增益,缩小可达界与外界的差距,提高系统的可达速率.