Rank-Two Beamforming and Power Allocation in Multicasting Relay Networks

TL;DR

This paper introduces a novel relay beamforming scheme using Alamouti coding and direct links to enhance multicasting performance, optimizing power allocation to maximize the minimum quality-of-service across destinations.

Contribution

It proposes a new relay multicasting scheme with Alamouti coding, considering direct links, and develops an iterative convex approximation algorithm for optimization.

Findings

Significant performance improvements over existing schemes.

Effective power allocation enhances minimum QoS.

Outperforms semidefinite relaxation-based algorithms.

Abstract

In this paper, we propose a novel single-group multicasting relay beamforming scheme. We assume a source that transmits common messages via multiple amplify-and-forward relays to multiple destinations. To increase the number of degrees of freedom in the beamforming design, the relays process two received signals jointly and transmit the Alamouti space-time block code over two different beams. Furthermore, in contrast to the existing relay multicasting scheme of the literature, we take into account the direct links from the source to the destinations. We aim to maximize the lowest received quality-of-service by choosing the proper relay weights and the ideal distribution of the power resources in the network. To solve the corresponding optimization problem, we propose an iterative algorithm which solves sequences of convex approximations of the original non-convex optimization problem. Simulation results demonstrate significant performance improvements of the proposed methods as compared with the existing relay multicasting scheme of the literature and an algorithm based on the popular semidefinite relaxation technique.