基础MIMO.pdf

Multiple-Antenna System (MIMO System) 历史、容量和应用 A Little Bit History • Before 1995 STRD Beam forming • 1995 Teladar Capacity in fading channels • 1996 Foschini D-BLAST Algorithm • 1998 Tarokh STC • 1998 Wolniansky V-BLAST: 20 bits/s/Hz(LAB) • 1999~current many researches for MIMO MIMO Capacity Assume that the number of Tx antenna is M and the number of Rx antenna is N, the channels are quasi-static flat Rayleigh fading channels, the elements 0f Tx antennas and Rx antennas are independent each other. 1. Capacity of MIMO in single user case 无线信道的衰落使信道容量的分析在很多 方面都变得复杂起来。如果编码和交织帧足够 长，以至于能够将衰落看作为各态历经的随机 过程，那么衰落AWGN信道容量就是无衰落 AWGN信道容量的期望值，即：(Tad Matsumoto and Markku Juntti,“Overview and Recent Challenges of MIMO Systems”，IEEE Vehicular Technology Society News ，May ， 2003)     H  C E log det I  HQH  H N    R NT  下图说明了上式，其中发送和接收天线数 目相等。可见容量随天线数目呈线性增长。这 种显著的容量增加是MIMO技术的亮点所在。 衰落的MIMO信道容量与收发天线数目(收发天线数相等)的关系 2. MIMO Capacity for Multi-user Access Channel ( Goldsmith Andrea, Capacity limits of MIMO channels[J], IEEE J Select Areas Communication, 2003, 21(6): 684~702 ) C MAC  *  1 Y ( R , , R ) : R  E[log I  H Q H ]