毫米波大规模MIMO-NOMA系统中基于动态子连接混合结构的预编码设计

针对毫米波大规模多输入多输出-非正交多址接入(massive multiple input multiple output non-orthogonal multiple access, mMIMO-NOMA)系统硬件成本和功耗过大问题, 基于动态子连接混合结构(dynamically sub-connected hybrid architecture, DSC-HA), 提出一种高效预编码方案。首先，在用户分组的基础上, 基于等效信道增益最大化原则, 利用Kuhn-Munkras算法匹配各NOMA簇用户的信道状态信息, 以实现动态天线分组, 进而完成模拟预编码设计。接着, 利用NOMA簇内强用户的等效信道来实现数字预编码设计, 以减小簇间干扰。最后, 通过优化簇内用户间功率分配来减小簇内用户间干扰。仿真结果表明, 基于DSC-HA的预编码方案不但系统和速率优于基于子连接混合结构的预编码方案, 而且能效明显优于基于全连接混合结构和基于全数字结构的预编码方案。

Precoder design based on dynamically sub-connected hybrid architecture in millimeter wave massive MIMO-NOMA systems

For the issues of the high hardware cost and power consumption in millimeter wave massive multiple input multiple output non-orthogonal multiple access (mMIMO-NOMA) systems, an efficient precoder design scheme, based on dynamically sub-connected hybrid architecture (DSC-HA) is proposed. Firstly, based on the user grouping, Kuhn-Munkras (KM) algorithm is used to match the channel state information of users in each NOMA cluster according to equivalent channel gain maximization criterion, so as to achieve dynamically antenna grouping, and then to complete the analog precoder design. After that, the digital precoder is designed with the equivalent channel of the strong user of each NOMA cluster to eliminate the inter-cluster interference. Finally, the power allocation of intra-cluster users of each NOMA cluster is optimized to reduce the inter-user interference. Simulation results show that the system sum rate of the DSC-HA scheme is not only better than that of the sub-connected hybrid architecture scheme, but also the energy efficiency is significantly higher than that of the fully-connected hybrid architecture-based and full digital architecture-based precoding schemes.