有限反馈的联合波束成形和调度方案

Scheme of joint beamforming and scheduling for MIMO downlink with limited feedback

提出一种基于有限反馈的联合波束成形和调度方案:用户利用一种结构化的码本对用户的信道方向信息(CDI)进行量化,采用一种低复杂度算法计算其最大的信号干扰信噪比(SINR),反馈给基站;基站根据接收到的反馈信息,按照和容量最大的准则选择出多个正交波束以及相应的多个用户.此方案不需考虑所有可能的用户子集,因此其复杂度仅随用户数呈线性增加.与Sharif等前人方案相比,该方案具有更高的吞吐量,避免了选择波束成形矢量时的用户冲突,基站不需要将波束成形矢量发给各个用户.

A practical joint beamforming and scheduling scheme is proposed that is foodbackied by quantized channel state information. Each user can quantize its channel direction information with a structured codebook, calculate its maximum signal-to-interference-plus-noise-ratio SINR） with a low complexity algorithm and feedback these information to the base station. Base station selects one set of orthogonal beamforming vectors and the associated users for downlink transmission such that the throughput is maximized based on these feedback information. In this approach, the proposed scheme has computational complexity that increases only linearly with the number of users since it does not require an exhaustive search over all possible subsets of users. Compared with the recently proposed scheme by Sharif etc. , the present scheme achieves higher downlink throughput, avoids multi-user conflicts when selecting beamforming vectors, and requires no broadcast of beamforming vectors.