Communicating Embedded Systems: Networks Applications

Chapter 2

Quality-of-Service Routing in Mobile Ad Hoc Networks ¹

2.1. Introduction

Ad hoc networks were introduced to provide connectivity between nodes in environments where it would be impossible to install an infrastructure (due to prohibitive costs or time constraints), or where existing facilities have been destroyed or taken out of service following an accident or earthquake, for example. The applications that can benefit from the capabilities offered by ad hoc networks are numerous, the most widespread being military applications, emergency and rescue operations, personal exchanges, and leisure uses. The strategic importance of these networks has led to a large number of research ventures in the field in the last 10 years.

The characteristics of ad hoc networks (particularly node mobility, the weakness of radio signals, collisions between nodes, and battery lifetimes), and the need to fulfill quality of service (QoS) requirements, make it very difficult to design and deploy these networks. In particular, the deployment of real-time multimedia applications (demanding in terms of time constraints, bandwidth, and packet loss rate) on ad hoc networks creates many challenges. Among the numerous problems encountered, we are interested in that of QoS routing. That is to say, protocols that allow us to select and maintain routes between sources and destinations for data exchange, while providing QoS guarantees (essentially in terms of delay and bandwidth).

The problem of QoS routing ...