CSI Compression for Distributed-MIMO With Centralized Precoding and Power Allocation

In distributed multiple-input multiple-output (D-MIMO), a large number of distributed antenna points (APs) are coordinated by a central processing unit (CPU) to serve a limited number of users at the same time/frequency resources, which brings improvements in spectral efficiency. The success of D-MIMO relies on precoding and power allocation, where they can be performed fully centralized on the CPU or distributed in the APs. The centralized approach presents higher spectral efficiency than the distributed implementation but requires a significant peak fronthaul traffic due to channel state information (CSI) exchange between APs and CPU. In this letter, we propose CSI compression schemes in order to enable practical centralized D-MIMO implementation. It is shown that depending on the compression configuration, the spectral efficiency can be as good as the case without compression.