Quality of service for ad hoc on-demand distance vector routing

Quality-of-service (QoS) is a desirable feature for mobile ad hoc networks (MANETs) due to the growth of multimedia applications. However, the mobile nature and dynamic topology of MANETs make it difficult to provide QoS assurance in such networks. In this paper we propose a QoS routing protocol based on AODV (QS-AODV), which creates routes according to application QoS requirements. A local repair mechanism is used to improve the packet delivery ratio. It is shown that QS-AODV provides performance comparable to AODV under light traffic conditions. In heavy traffic, QS-AODV provides higher packet delivery ratios and lower routing overheads, at a cost of slightly longer end-to-end delays. The effects of mobility on performance is also presented.

I. Introduction

A mobile ad hoc network (MANET) is a collection of mobile nodes that form a wireless network without the use of a fixed infrastructure (e.g., base stations or access points), or centralized administration. Quality-of-Service (QoS) is a desirable feature for MANETs due to the growth of multimedia applications [1]. Since the available bandwidth is limited, proper bandwidth management is necessary to accommodate these applications. A number of approaches have been proposed to provide QoS assurance in wired networks [2] [3]. However, due to the characteristics of the wireless medium, wire-based QoS models are not appropriate for ad hoc networks. For example, the dynamic nature of an ad hoc network makes it extremely difficult to obtain accurate knowledge of the network state. Furthermore, constant updates of link state information are required to make optimal routing decisions, which results in extensive control overhead. This can be prohibitive in bandwidth constrained environments.