Alamouti-Like Transmission Schemes in Distributed MIMO Networks

TL;DR

This paper explores the use of Alamouti-like STFBC in distributed MIMO networks to enhance diversity at the user end without requiring channel state information, aiming to improve robustness and spectral efficiency.

Contribution

It introduces a novel STFBC-based approach for distributed MIMO systems that operates without channel knowledge, optimizing clustering and demonstrating potential performance gains.

Findings

Enhanced diversity at UE without CSI

Robust mode maintains data rate under poor channels

Performance gains over traditional precoding techniques

Abstract

The purpose of the study is to investigate potential benefits of using Alamouti-like orthogonal space-time-frequency block codes (STFBC) in distributed multiple-input multiple-output (D-MIMO) systems to increase the diversity at the UE side when instantaneous channel state information (CSI) is not available at radio units (RUs). Most of the existing transmission techniques require instantaneous CSI to form precoders which can only be realized together with accurate and up-to-date channel knowledge. STFBC can increase the diversity at UE side without estimating the downlink channel. Under challenging channel conditions, the network can switch to a robust mode where a certain data rate is maintained for users even without knowing the channel coefficients by means of STFBC. In this study, it will be mainly focused on clustering of RUs and user equipment, where each cluster adopts a possibly different orthogonal code, so that overall spectral efficiency is optimized. Potential performance gains over known techniques that can be used when the channel is not known will be shown and performance gaps to sophisticated precoders making use of channel estimates will be identified.