Coded Random Access: Applying Codes on Graphs to Design Random Access Protocols

TL;DR

This paper introduces coded random access protocols that leverage graph-based coding techniques and successive interference cancellation to significantly improve performance in machine-to-machine communication networks.

Contribution

It proposes a novel framework that maps access protocols to erasure-correcting codes on graphs, enabling the design of more efficient random access protocols.

Findings

Coded random access outperforms traditional ALOHA in efficiency.

The framework allows upgrading legacy ALOHA systems with coding techniques.

Use of graph-based codes enables better handling of collisions.

Abstract

The rise of machine-to-machine communications has rekindled the interest in random access protocols as a support for a massive number of uncoordinatedly transmitting devices. The legacy ALOHA approach is developed under a collision model, where slots containing collided packets are considered as waste. However, if the common receiver (e.g., base station) is capable to store the collision slots and use them in a transmission recovery process based on successive interference cancellation, the design space for access protocols is radically expanded. We present the paradigm of coded random access, in which the structure of the access protocol can be mapped to a structure of an erasure-correcting code defined on graph. This opens the possibility to use coding theory and tools for designing efficient random access protocols, offering markedly better performance than ALOHA. Several instances of coded random access protocols are described, as well as a case study on how to upgrade a legacy ALOHA system using the ideas of coded random access.