Reliable, Real-Time Routing in Wireless Sensor and Actuator Networks

Martin Krogmann,Mike Heidrich,Daniel Bichler,Guido Stromberg,Daniel Barisic

doi:10.5402/2011/943504

Abstract

We present a novel Reliable, Real-time Routing protocol (3R) based on multipath routing for highly time-constrained Wireless Sensor and Actuator Networks (WSANs). The protocol consists of a newly designed routing metric and a routing algorithm utilizing this metric. Our routing metric enables strong Quality-of-Service (QoS) support based on parallel transmissions which significantly reduces transmission delays in WSANs. A routing algorithm utilizing this metric is presented based on Dijkstra's shortest path. A novel Medium Access Control (MAC) layer that supports dynamical adjustments of retransmission limits, reduces traffic overhead in multipath routing protocols. Thorough simulations have been performed to evaluate the routing protocol, and the results show that real-time performance of WSANs can be vastly improved.

Highlights

Wireless Sensor Networks (WSNs) have moved into realworld applications, and their extension to wireless sensor and actuator networks (WSANs) is in progress
After that we present an algorithm utilizing this metric and a trafficreducing Medium Access Control (MAC) layer exploiting the characteristics of our routing protocol
Our approach to reduce transmission latencies below those latencies achieved with state-of-the-art routing metrics is to send packets at the same time via several disjoint routes and have immediate retransmissions on parallel routes, which takes no additional time

Summary

Introduction

Wireless Sensor Networks (WSNs) have moved into realworld applications, and their extension to wireless sensor and actuator networks (WSANs) is in progress. In the industrial sector many applications for WSANs can be found that have hard real-time requirements such as open- or closed-loop controlled systems [3]. These applications use the WSAN for measuring and processing data and for controlling the system if necessary. The lack of reliable, real-time protocols for WSANs state a big problem for enabling WSANs in such control systems. One reason for this lack of suitable protocols might be that energy awareness and real-time performance are often conflicting objectives [4]

Results

Discussion

Conclusion