Coordinated Multicast Beamforming in Multicell Networks

TL;DR

This paper introduces decentralized algorithms for coordinated multicast beamforming in multicell networks, optimizing power and SINR to improve performance with limited inter-base station communication.

Contribution

It proposes novel decentralized algorithms for QoS and max-min SINR beamforming, with convergence guarantees and near-optimal solutions, advancing multicell multicast communication techniques.

Findings

Decentralized algorithm converges to optimal or near-optimal solutions.

Significant performance improvements over conventional schemes.

Effective handling of limited information sharing among base stations.

Abstract

We study physical layer multicasting in multicell networks where each base station, equipped with multiple antennas, transmits a common message using a single beamformer to multiple users in the same cell. We investigate two coordinated beamforming designs: the quality-of-service (QoS) beamforming and the max-min SINR (signal-to-interference-plus-noise ratio) beamforming. The goal of the QoS beamforming is to minimize the total power consumption while guaranteeing that received SINR at each user is above a predetermined threshold. We present a necessary condition for the optimization problem to be feasible. Then, based on the decomposition theory, we propose a novel decentralized algorithm to implement the coordinated beamforming with limited information sharing among different base stations. The algorithm is guaranteed to converge and in most cases it converges to the optimal solution. The max-min SINR (MMS) beamforming is to maximize the minimum received SINR among all users under per-base station power constraints. We show that the MMS problem and a weighted peak-power minimization (WPPM) problem are inverse problems. Based on this inversion relationship, we then propose an efficient algorithm to solve the MMS problem in an approximate manner. Simulation results demonstrate significant advantages of the proposed multicast beamforming algorithms over conventional multicasting schemes.