TDMH-MAC: Real-time and multi-hop in the same wireless MAC

TL;DR

This paper introduces TDMH-MAC, a real-time multi-hop wireless MAC protocol that uses synchronized TDMA scheduling and constructive interference to support deterministic communication in mesh networks.

Contribution

It presents a novel MAC protocol that combines clock synchronization and interference-based flooding to enable real-time multi-hop communication over IEEE 802.15.4.

Findings

Protocol supports multi-hop mesh networks with real-time guarantees

Implemented and tested in simulation and real-world deployment

Achieves deterministic, point-to-point communication with redundancy

Abstract

Supporting real-time communications over Wireless networks (WSNs) is a tough challenge, due to packet collisions and the non-determinism of common channel access schemes like CSMA/CA. Real-time WSN communication is even more problematic in the general case of multi-hop mesh networks. For this reason, many real-time WSN solutions are limited to simple topologies, such as star networks. We propose a real-time multi-hop WSN MAC protocol built atop the IEEE 802.15.4 physical layer. By relying on precise clock synchronization and constructive interference-based flooding, the proposed MAC builds a centralized TDMA schedule, supporting multi-hop mesh networks. The real-time multi-hop communication model is connection-oriented, sing guaranteed time slots, and enables point-to-point communications also with redundant paths. The protocol has been implemented in simulation using OMNeT++, and the performance has been verified in a real-world deployment using Wandstem WSN nodes.