Bilinear Precoder Based Efficient Rate Splitting Method in FDD Systems

TL;DR

This paper introduces a low-cost, efficient rate splitting method for FDD multi-user MISO systems that relies on second-order channel statistics and offers reduced complexity through closed-form iterative solutions.

Contribution

It presents a novel iterative optimization algorithm for rate splitting in FDD MISO systems that simplifies design by using second-order statistics and closed-form updates.

Findings

Reduces system design complexity significantly.

Eliminates need for interior point solvers like CVX.

Achieves efficient precoding with low computational cost.

Abstract

In this work, we propose a low-cost rate splitting (RS) technique for a multi-user multiple-input single-output (MISO) system operating in frequency division duplex (FDD) mode. The proposed iterative optimisation algorithm only depends on the second-order statistical channel knowledge and the pilot training matrix. Additionally, it offers a closed-form solution in each update step. This reduces the design complexity of the system drastically as we only need to optimise the precoding filters in every coherence interval of the covariance matrices, instead of doing that in every channel state information (CSI) coherence interval. Moreover, since the algorithm is based on closed-form solutions, there is no need for interior point solvers like CVX, which are typically required in most state-of-the-art techniques.