On the Stability of Contention Resolution Diversity Slotted ALOHA

TL;DR

This paper develops a Markov Chain-based model to analyze the stability and delay characteristics of CRDSA in TDMA-based RA channels with SIC, demonstrating its superior stability and throughput over traditional Slotted ALOHA.

Contribution

It introduces a comprehensive mathematical model for CRDSA stability analysis, enabling prediction of stability regions, delays, and parameter selection, validated by simulations.

Findings

CRDSA outperforms Slotted ALOHA in throughput and stability.

The model accurately predicts stability regions and delays.

CRDSA maintains stability with higher user loads.

Abstract

In this paper a Time Division Multiple Access (TDMA) based Random Access (RA) channel with Successive Interference Cancellation (SIC) is considered for a finite user population and reliable retransmission mechanism on the basis of Contention Resolution Diversity Slotted ALOHA (CRDSA). A general mathematical model based on Markov Chains is derived which makes it possible to predict the stability regions of SIC-RA channels, the expected delays in equilibrium and the selection of parameters for a stable channel configuration. Furthermore the model enables the estimation of the average time before reaching instability. The presented model is verified against simulations and numerical results are provided for comparison of the stability of CRDSA versus the stability of traditional Slotted ALOHA (SA). The presented results show that CRDSA has not only a high gain over SA in terms of throughput but also in its stability.