MIMO Mutli-Cell Processing: Optimal Precoding and Power Allocation

TL;DR

This paper analyzes optimal precoding and power allocation in multi-cell MIMO systems with cooperative base stations, providing new iterative methods and closed-form solutions for high-SNR regimes to maximize user rates.

Contribution

It introduces a novel iterative approach and closed-form expressions for optimal precoding in cooperative MIMO, addressing the NP-hard problem in high-SNR regimes.

Findings

Derived a fixed point equation for optimal precoding in asymptotic regimes.

Developed a closed-form solution for high-SNR precoding matrix.

Proposed distributed algorithms for power allocation and precoding.

Abstract

We investigate the optimal power allocation and optimal precoding for a cluster of two BSs which cooperate to jointly maximize the achievable rate for two users connecting to each BS in a MCP framework. This framework is modeled by a virtual network MIMO channel due to the framework of full cooperation. In particular, due to sharing the CSI and data between the two BSs over the backhaul link. 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 UL, and a precoding algorithm for the DL.