Exploring the Non-Overlapping Visibility Regions in XL-MIMO Random Access Protocol

TL;DR

This paper introduces a novel random access protocol for XL-MIMO systems that leverages non-overlapping visibility regions of UEs to enhance sum rate, reduce latency, and improve connectivity in high-density scenarios.

Contribution

The paper proposes the NOVR-XL RA protocol, utilizing non-overlapping VRs of UEs for improved scheduling and performance in XL-MIMO systems.

Findings

Significant sum rate improvements over traditional schemes

Reduced access latency in high-density user scenarios

Enhanced connectivity performance in XL-MIMO systems

Abstract

The recent extra-large scale massive multiple-input multiple-output (XL-MIMO) systems are seen as a promising technology for providing very high data rates in increased user-density scenarios. Spatial non-stationarities and visibility regions (VRs) appear across the XL-MIMO array since its large dimension is of the same order as the distances to the user-equipments (UEs). Due to the increased density of UEs in typical applications of XL-MIMO systems and the scarcity of pilots, the design of random access (RA) protocols and scheduling algorithms become challenging. In this paper, we propose a joint RA and scheduling protocol, namely non-overlapping VR XL- MIMO (NOVR-XL) RA protocol, which takes advantage of the different VRs of the UEs for improving RA performance, besides seeking UEs with non-overlapping VRs to be scheduled in the same payload data pilot resource. Our results reveal that the proposed scheme achieves significant gains in terms of sum rate compared with traditional RA schemes, as well as reducing access latency and improving connectivity performance as a whole.