基于虚拟子阵列的多用户大规模MIMO混合预编码

Hybrid Precoding Based on Virtual Subarray for Multiuser Massive MIMO Systems

为了在多用户大规模多入多出系统中获得更高空间分集增益,提出一种基于虚拟子阵列的部分连接结构模数混合预编码方案.此方案允许射频链路动态连接发射天线.首先通过提取空口信道的共轭相位设计模拟预编码矩阵,并提出逐元最大化虚拟子阵列增益算法以获得更大模拟预编码增益,然后对等效信道实施迫零数字预编码.仿真结果表明,Rayleigh衰落信道中所提虚拟子阵列方案比传统的部分连接结构方案能取得更高的频谱效率,且对相位量化误差不敏感.

In order to obtain more spatial diversity gain in multiuser massive multiple-input multiple-output(MIMO)systems,a hybrid precoding scheme based on virtual subarray(VSA)for partially-connected structure(PCS)is proposed in this paper.The scheme allows the RF chain to be connected with the transmitting antennas dynamically.The analog precoding matrix is firstly designed by extracting the conjugate phase of the air interface channel,and an algorithm maximizing the VSA gain element-by-element is proposed to obtain greater analog precoding gain.Then a zero-forcing digital precoding is performed for the equivalent channel.Simulation results show that the VSA scheme achieves much higher spectral efficiency than the conventional PCS ones in Rayleigh fading channels,and is also insensitive to the phase quantized error.