Hybrid Analog-Digital Millimeter-Wave MU-MIMO Transmission With Virtual Path Selection

In this letter, we propose a low-complexity hybrid precoding and combining design for the millimeter-wave MU-MIMO transmission, applicable to both fully connected and sub-connected structures. Analog precoding and combining schemes are first designed, where a joint approach, a decoupled approach, and a sub-optimal approach are proposed to harvest the array gain. Virtual path selection is performed to maximize the channel gain of the analog effective channel. Then, based on the effective channel, a low-dimensional zero-forcing precoding is applied in the baseband to manage the interference. The simulation results show that the proposed techniques offer an enhanced performance-complexity tradeoff compared with both existing hybrid schemes and fully digital schemes.