多用户MIMO系统在有限反馈下结合预编码与调度算法的研究

Study of Joint Precoding and Scheduling Algorithm for Multiuser MIMO System with Limited Feedback

研究了多用户多输入多输出(MIMO)系统在有限反馈下的一种结合单位预编码与用户调度算法的方案。在该系统中每一用户都具有多个接收天线,该方案具有较大的多用户分集增益和较小的计算复杂度,从而能够减少系统中的用户间干扰。每个用户独立地决定自己的天线合并矢量,并将最优波束矢量以及对应的估计信干噪比通过有限反馈信道反馈给基站,此时基站获取了相应的用户信道信息和用户间干扰信息。基于接收到的反馈信息,基站从预定义的码本中选取和速率最大的最优子集进行系统预编码,然后依照预编码矩阵调度欧氏距离最小的用户且用户个数不超过发送天线的数目。仿真结果显示该方案有效地改善了系统速率,特别是在用户数目较多或者信道环境较好的情况下。

This paper studies a project combining unit pre-coding and user scheduling algorithm of multiuser multi-input multi-output （MIMO） system with limited feedback. In the system, each user is equipped with multiple reception antennas. The low computational complexity and big multiuser diversity gain is fetched in this project,which can reduce inter-user interferences in the system. Each user independently determines its antenna combination vector and feeds back its optimum beam vector and corresponding estimated signal to interference plus noise ratio （SINR） to the base station through the limited feedback channel,then the base station （BS） fetches the corresponding user channel information and inter-user jamming information. Based on received feedback informa- tion,the optimum subset with maximal sum-speed in predefined codebook is selected by the base station to be pre-coded, then according to precoding matrix, users with the minimized Euclidean dis- tance are dispatched and the number of selected users is less than the number of transmission an- tennas. Simulation results show that the proposed project effectively improves the system speed, es- pecially in the status that the number of users is big or channel environment is well.