A greedy approach for mmWave hybrid precoding with subarray architectures

We consider a point-to-point mmWave link with hybrid digital-analog transceivers, where the analog stage is realized with a network of phase shifters. Moreover, we concentrate on a case particularly relevant from the practical perspective. Namely, we constrain the analog stage such that disjoint antenna subarrays are processed separately in the analog domain. In this work, a novel precoding and combining strategy is developed. In order to exploit the inherent modularity of the analog stage in the subarray architectures, we separate the design of the digital and analog processing and concentrate on the latter. Namely, for the design of the analog stage we propose a subspace-arrangement based greedy algorithm.