A Grant-based Random Access Protocol in Extra-Large Massive MIMO System

TL;DR

This paper introduces a grant-based random access protocol tailored for extra-large massive MIMO systems, leveraging spatial non-stationarities and visibility regions to enhance access efficiency and reduce latency.

Contribution

It proposes a modified SUCRe protocol that exploits overlapping visibility regions in XL-MIMO, improving access attempts and acceptance rates.

Findings

Increased number of successful access attempts.

Reduced latency in pilot allocation.

Enhanced utilization of spatial non-stationarities.

Abstract

Extra-large massive multiple-input multiple-output (XL-MIMO) systems is a new concept, where spatial non-stationarities allow activate a high number of user equipments (UEs). This paper focuses on a grant-based random access (RA) approach in the novel XL-MIMO channel scenarios. Modifications in the classical Strongest User Collision Resolution (SUCRe) protocol have been aggregated to explore the visibility regions (VRs) overlapping in XL-MIMO. The proposed grant-based RA protocol takes advantage of this new degree of freedom for improving the number of access attempts and accepted UEs. As a result, the proposed grant-based protocol for XL-MIMO systems is capable of reducing latency in the pilot allocation step.