分布式MIMO系统发送天线选择与预编码联合设计

Joint transmit antenna selection and pre-coding in distributed MIMO systems

摘要:

为了抑制多用户分布式多入多出(MIMO)系统中的同道干扰(CCI)，使系统同时服务于更多用户，提出一种发送天线选择与预编码的联合设计方法。该方法立足于分布式MIMO系统基站端天线较多的特点，将下行发送天线选择与信漏噪比(SLNR)预编码相结合，通过为用户选择不同天线，从根本上减少CCI；在为每个用户选择天线时，先以信道子矩阵的迹为依据进行端口选择，再采用逐减的方法选择使SLNR损失值最小的天线，以保证每个用户对其他用户的干扰尽量小，从而达到进一步抑制CCI的目的。复杂度分析和仿真结果表明，该方法在具有较低复杂度同时，其容量性能仍可逼近最优算法；较之单纯的SLNR预编码，在相同的容量性能约束下，其能够有效增加系统同时服务的用户数。

Abstract:

To suppress the Co-Channel Interference(CCI) and increase the number of served users in multi-user distributed Multiple Input Multiple Output(MIMO) systems, a joint transmit antenna selection and pre-coding scheme is proposed based on the characteristics that there are a large amount of antennas at the base station in distributed MIMO systems. In the proposed scheme, downlink transmits antenna selection and Signal to Leakage and Noise Ratio(SLNR) pre-coding are combined together. On the one hand, it selects different antennas for each user to radically decrease the CCI. On the other hand, during the antenna selection process, antenna ports are firstly selected according to the trace of the channel sub-matrices. Then antennas which minimize the SLNR loss for each user are selected with an elimination method in order to make interference to other users as small as possible and further suppress the CCI. Compared with the optimal algorithm, the proposed algorithm shows great superiority on complexity with a capacity performance similar to the optimal algorithm. It can make the system provide service to more users than SLNR pre-coding under the same capacity constraint.