Two-Step Interference Cancellation for Energy Saving in Irregular Repetition Slotted ALOHA

TL;DR

This paper proposes a two-step interference cancellation method for IRSA that reduces energy consumption by early transmission termination, especially effective at low loads, without sacrificing throughput.

Contribution

It introduces a novel energy-saving technique for IRSA involving intermediate decoding and early termination, validated through analysis and simulation.

Findings

33% energy saving at 10% load

Maintains throughput comparable to standard IRSA

Effective in low-load scenarios

Abstract

We evaluate a modification of irregular repetition slotted ALOHA (IRSA) involving intermediate decoding and early transmission termination by some nodes, upon their decoding success. This is meant to avoid unnecessary transmissions, thereby reducing energy consumption. We expect this to be particularly useful at low loads, where most transmissions can be avoided as they do not often result in a collision and are therefore redundant. To validate this proposal, we observe that most of the literature related to IRSA considers an asymptotic heavily loaded regime; thus, we also present a model of energy consumption and success probability for frames of limited length and low offered loads. Thanks to our analysis, also confirmed by simulation, we are able to show that the proposed technique is able to reduce IRSA energy consumption by minimizing transmissions, while preserving performance gains over standard ALOHA. For example, we are able to get a 33% energy saving at offered loads around 10% without affecting throughput.