Optimal Power Allocation and Optimal Precoding with Multi-Cell Processing

In this paper, we investigate the optimal power allocation and optimal precoding for a cluster of two base stations(BS) which cooperate to jointly maximize the achievable rate for two users connecting to each BS in a multi-cell processing (MCP) framework. We provide a generalized fixed point equation of the optimal precoder in the asymptotic regimes of the low- and high-snr. We introduce a new iterative approach that leads to a closed form expression for the optimal precoding matrix in the high-snr regime which is known to be an NP-hard problem. Two MCP distributed algorithms have been introduced, a power allocation algorithm for the uplink (UL), and a precoding algorithm for the downlink (DL).