A variable-phase-shifter (VPS) architecture with hybrid precoding for mixture use of phase shifters and switches, is proposed for millimeter wave massive multiple-input multiple-output communications. For the VPS architecture, a hybrid precoding design (HPD) scheme, called VPS-HPD, is proposed to optimize the phases according to the channel state information by alternately optimizing the analog precoder and digital precoder. To reduce the computational complexity of the VPS-HPD scheme, a low-complexity HPD scheme for the VPS architecture (VPS-LC-HPD) including alternating optimization in three stages is then proposed, where each stage has a closed-form solution and can be efficiently implemented. To reduce the hardware complexity introduced by the large number of switches, we consider a group-connected VPS architecture and propose a HPD scheme, where the HPD problem is divided into multiple independent subproblems with each subproblem flexibly solved by the VPS-HPD or VPS-LC-HPD scheme. Simulation results verify the effectiveness of the propose schemes and show that the proposed schemes can achieve satisfactory spectral efficiency performance with reduced computational complexity or hardware complexity.
翻译:为混合使用相位移器和开关,建议为毫米波大规模多输出多输出多输出通信建立一个多阶段混合编码的多阶段交替转换器(VPS)结构。对于光波结构,建议采用称为VPS-HPD的混合预编码设计(HPD)计划,根据频道状态信息优化各个阶段,为此,可同时优化模拟预码器和数字预码器;为降低VPS-HPD计划的计算复杂性,然后为VPS结构(VPS-LC-HPD)提出低复杂性的HDPD计划,包括三个阶段的交替优化,每个阶段都有封闭式解决方案,并可以高效实施。为减少大量开关带来的硬件复杂性,我们考虑一个组合相连的VPS结构,并提议一个HPD计划,将HPD问题分为多个独立的子问题,每个子问题由VPS-HDD或VPS-LDPD计划灵活解决。模拟结果验证了拟议计划的有效性,并显示拟议复杂度的硬度计算方法能够实现令人满意的光谱效率。