An Analytical Model for S-ALOHA Performance Evaluation in M2M Networks

TL;DR

This paper develops an accurate analytical model for S-ALOHA in M2M networks, considering capture effects and power diversity, to improve network performance evaluation and design.

Contribution

It introduces a low-complexity analytical model that accounts for capture effect and power diversity, aiding in S-ALOHA network dimensioning and optimization.

Findings

The model accurately predicts packet loss, throughput, and energy efficiency.

Imperfect power control can enhance performance when combined with capture effects.

Power diversity strategies should consider cost, control precision, and capture ratio.

Abstract

The S-ALOHA (i.e. slotted-ALOHA) protocol is recently regaining interest in Lower Power Wide Area Networks (LPWAN) handling M2M traffic. Despite intensive studies since the birth of S-ALOHA, the special features of M2M traffic and requirements highlight the importance of analytical models taking into account performance-affecting factors and giving a thorough performance evaluation. Fulfilling this necessity is the main focus of this paper: we jointly consider the impact of capture effect, diversity of transmit power levels with imperfect power control. We propose a low-complexity but still accurate analytical model capable of evaluating S-ALOHA in terms of packet loss rate, throughput, energy-efficiency and average number of transmissions. The proposed model is able to facilitate dimensioning and design of S-ALOHA based LPWAN. The comparison between simulation and analytical results confirms the accuracy of our proposed model. The design guides about S-ALOHA based LPWAN deduced from our model are: the imperfect power control can be positive with capture effect and and appropriate transmit power diversity strategy. The transmit power diversity strategy should be determined by jointly considering network charges level, power control precision and capture ratio to achieve optimal performance of S-ALOHA.