Distributed Precoding with Local Power Negotiation for Coordinated Multi-Point Transmission

Coordinated multi-point (CoMP) transmission has recently received much attention due to its promise in effectively mitigating the inter-cell interference in a cellular network. In this paper, we compare two different architectures for CoMP transmission. The first architecture partitions all basestations in the network into disjoint clusters with signal transmissions within each cluster being coordinated independently of one another at a centralized location of each cluster. In the second architecture, the processing for coordinated transmission is distributed among overlapping clusters, each centered around one cell. For this architecture, we propose a simple method for computing linear multi-user precoders for all clusters in a distributed manner, where the precoders are chosen not only to maximize throughput to the served users but also to reduce interference with other users in overlapping clusters. A low-complexity iterative algorithm is proposed for negotiating transmit power levels among adjacent clusters to ensure the power constraints at all transmission points are satisfied. Through system simulations using practical channel models, we show that the distributed architecture substantially outperforms the cluster-wise centralized architecture in maximizing the user data throughputs in the network.