Distributed Precoding for Network MIMO

Abstract

Network MIMO, in which base stations cooperate and coordinate through a centralized design, is an attractive technology that promises higher spectral efficiency and lower inter-cell interference. However, such performance gain comes at the cost of extensive exchange of signal information (SI), channel state information (CSI), and coordinated precoding information over backhaul links. In this paper, we propose a distributed precoding strategy for network MIMO which does not require explicit exchange of SI and CSI among the cooperating base stations. Instead, each base station derives its own precoder to simultaneously minimize the out-of-cell interference as well as maximize the intra-cell sum rate. A robust design is also proposed, to address CSI imperfectness, and which recovers some of the rate reduction due to the CSI uncertainty.