Computationally Efficient Robust Beamforming for SINR Balancing in Multicell Downlink

TL;DR

This paper introduces a computationally efficient robust beamforming method for SINR balancing in multicell downlink systems with imperfect channel estimates, using SOCP approximation to reduce complexity and handle various uncertainties.

Contribution

It presents a novel SOCP-based approximation for robust beamforming that significantly reduces computational complexity and broadens applicability to different uncertainty models.

Findings

SOCP-based design reduces computational complexity compared to SDP.

Proposed methods perform well with massive antenna arrays.

Numerical results confirm effectiveness in practical scenarios.

Abstract

We address the problem of downlink beamformer design for signal-to-interference-plus-noise ratio (SINR) balancing in a multiuser multicell environment with imperfectly estimated channels at base stations (BSs). We first present a semidefinite program (SDP) based approximate solution to the problem. Then, as our main contribution, by exploiting some properties of the robust counterpart of the optimization problem, we arrive at a second-order cone program (SOCP) based approximation of the balancing problem. The advantages of the proposed SOCP-based design are twofold. First, it greatly reduces the computational complexity compared to the SDP-based method. Second, it applies to a wide range of uncertainty models. As a case study, we investigate the performance of proposed formulations when the base station is equipped with a massive antenna array. Numerical experiments are carried out to confirm that the proposed robust designs achieve favorable results in scenarios of practical interest.