Distributed coordinated multi-point downlink transmission with over-the-air communication

Base station cooperation transmission, which is also known as coordinated multi-point (CoMP) transmission, is a promising technique to improve system spectrum efficiency in cellular networks, especially for multiple antenna systems. However, the performance gain is significant only when cooperative base stations can gather channel state information (CSI) from all their serving users and can share CSI without delay. In this paper, we propose a distributed downlink CoMP transmission scheme through over-the-air communication among all base stations, which can reduce not only the infrastructural overhead but also the delay of acquiring CSI. We first analyze the CSI acquisition methods in centralized and decentralized CoMP framework. Then we propose a distributed multi-user scheduling and precoding method. Simulation results show that the proposed framework and scheduling algorithm outperforms the centralized and decentralized CoMP when the outdated CSI led by backhaul latency is considered.