EchoRing: A Low-Latency, Reliable Token-Passing MAC Protocol for Wireless Industrial Networks

Spurred by recent industrial trends, such as factory automation or phase synchronization in the smart grid, there is a significant interest for wireless industrial networks lately. In contrast to traditional applications, the focus is on carrying out communication at very short latencies together with high reliabilities. Meeting such extreme requirements with wireless networks is challenging. A potential candidate for such a network is a token-passing protocol, as it allows to bound latencies. However, it lacks mechanisms to cope with the dynamics of wireless channels. In this paper, we present EchoRing, a novel wireless token-passing protocol. Cooperative communication and an improved fault tolerance allow this decentralized protocol to support industrial applications over wireless networks. Based on experimental results, we demonstrate the suitability of EchoRing to support demands of industrial applications. EchoRing outperforms other schemes by several orders of magnitude in terms of reliability for latencies of and below 10 ms.