A High Throughput Pilot Allocation for M2M Communication in Crowded Massive MIMO Systems

TL;DR

This paper introduces SUCR-IPA, a novel pilot allocation scheme for crowded massive MIMO systems that significantly improves throughput and reduces access attempts by resolving intra-cell pilot collisions in M2M communication.

Contribution

The paper proposes the SUCR-IPA scheme, combining collision resolution with idle pilot contention, and provides an analytical method to evaluate its performance.

Findings

SUCR-IPA increases system throughput significantly.

The scheme reduces the number of access attempts.

Simulation results match analytical predictions.

Abstract

A new scheme to resolve the intra-cell pilot collision for M2M communication in crowded massive multiple-input multiple-output (MIMO) systems is proposed. The proposed scheme permits those failed user equipments (UEs), judged by a strongest-user collision resolution (SUCR) protocol, to contend for the idle pilots, i.e., the pilots that are not selected by any UE in the initial step. This scheme is called as SUCR combined idle pilots access (SUCR-IPA). To analyze the performance of the SUCR-IPA scheme, we develop a simple method to compute the access success probability of the UEs in each random access slot (RAST). The simulation results coincide well with the analysis. It is also shown that, compared to the SUCR protocol, the proposed SUCR-IPA scheme increases the throughput of the system significantly, and thus decreases the number of access attempts dramatically.