Analysis of two-stage precoding schemes for massive multi-user MIMO downlink systems

Abstract

Massive MIMO has been regarded as one of the most promising technologies for the 5G system, where precoding schemes have large potential to improve the network efficiency. However, substantial antennas deployment in massive MIMO systems make the generalized precoding schemes too complex to implement, while two-stage precoding strategies embrace flexible antenna structure and reduce both hardware complexity and computation complexity. For this reason, we present an exhaustive analysis of two-stage precoding designs under distinctive antenna structures, meanwhile, both precoding performance gains and hardware complexity are studied. Our simulation results reveal that precoding performance is still subject to hardware complexity. However, there is a tradeoff between precoding performance attained and hardware cost imposed. We also provide a guideline on antenna structure selection to achieve a better balance between the performance and cost.