基于Schmidt正交化的多天线选择复用

该文从提高信道传输有效性的角度,提出了一种新的多天线选择发送策略--贪婪搜索(GS)法,使用这种方法挑选出使容量最大化的发送天线组合作为传输信号的天线.此法在结合注水(waterfilling)法进行天线功率分配的情况下,与理想的全天线注水法相比,可以减小发射机的复杂度,在独立信道下传输容量略有损失,在相关信道下可以提高传输容量,并且所付出的代价是仅需要对信道矩阵进行Schmidt正交化变换.这种方法一般用于信道矩阵列不满秩,即发送端天线数大于接收端天线数,发送端已知信道矩阵的情况(与注水法结合)或者接收端已知信道矩阵的情况(等功率分配).

Selected Transmission of Multiple Antennas Based on Schmidt Orthogonalization

A new selected transmission scheme of multiple antennas is proposed, named Greedy Search (GS) method. The transmit antennas selected from all antennas can be used as the active transmit antennas. When used with waterfilling power allocation, GS method can decrease the complexity of signal design on antennas, compared with Waterfilling power allocation on all Antennas (WA). The capacity loss over WA in independent fading channels is rather small, moreover, this method can get capacity gain over WA in spatial dependent fading channels. The cost of capacity gain of GS is the necessity of Schmidt orthogonalization on the channel matrix. GS can be used when the channel matrix is not column-full-rank, i.e., the number of transmit antennas is greater than that of receive antennas, and the transmitter can get the full channel matrix information (used with waterfilling power allocation); or; the receiver can get the full channel matrix information (used with equal power allocation).