Subband Random Sensing Grant Free Uplink for URLLC in Unlicensed Spectrum

TL;DR

This paper introduces a novel subband random sensing scheme for grant-free uplink in unlicensed spectrum, significantly improving reliability and reducing collisions for URLLC applications.

Contribution

It proposes a new SRS scheme that combines subband sensing, user grouping, and random access to enhance spectrum efficiency and reliability in unlicensed bands.

Findings

Lower collision probability compared to contention-based schemes

Higher reliability demonstrated through analysis and simulations

Reduces spectrum wastage in sporadic traffic scenarios

Abstract

In this paper, we propose a novel scheme called subband random sensing (SRS) grant free uplink for ultra-reliable low-latency communication (URLLC) in unlicensed spectrum. The SRS grant free uplink creatively combines the subband sensing, user grouping and random access, which allows a user sensing the unlicensed spectrum to use available sub-resources in a wideband and reduce collisions with other users. The new scheme overcomes the severe spectrum wastage problem of the semi-persistent scheduling (SPS) uplink adopted by new radio (NR) release 16 in applications with sporadic traffic. Compared with the contention based grant free uplink, the new scheme achieves much lower collision probability, which directly leads to higher reliability. Analysis and simulations are provided to prove the exceptional performances.