部分反馈信息下多用户多输入多输出下行链路的容量优化

Capacity Optimization in Multiuser Multiple Input Multiple Output Downlink with Partial Feedback Information

针对多用户多输入多输出下行链路中,基于部分信道状态信息反馈的联合发送方法不能有效抑制多用户间相互干扰的问题,提出了一种支持各用户信号独立检测的多用户联合发送方案.该方案只需要各用户信道响应矩阵的主右奇异向量作为反馈信息,在计算预处理矩阵时引入正交化操作,与已有方案相比,在增加少量前馈信息的条件下,可以最小化多用户间相互干扰,提升系统容量.仿真结果表明,所提出的方案能够提高检测信干噪比,降低系统的平均误码率,在发送、接收天线数为4、平均发送信噪比为20 dB时,系统容量比无正交化时提高了1倍以上.

Focusing on the problem that joint transmission based on partial feedback channel state information cannot effectively cancel the interuser interference in multiuser multiple input multi ple output downlink systems, a joint transmission scheme that allows independent signal detection for each user was proposed. This scheme requires only the principal right singular vector of each user＇s channel response matrix regarded as feedback information. By introducing orthogo nalization in the computation of the prerocessing matrix, with little increasing of feedforward information, this scheme can minimize interuser interference and improve the system capacity compared with the existing scheme. Simulation results show that the proposed scheme can in crease the detection signal-to-interference-noise ratio, and therefore reduce the bit error rate. At 20 dB average signal-to-noise ratio and with 4 transmitting and 4 receiving antennas, the system capacity increases double as large as that of non-orthogonalization.