QoS Routing Solutions for Mobile Ad Hoc Network

Abstract

For the past decade, the field of mobile ad hoc networks (MANETs) [1] has been accepted as a legitimate area of research. It avoids the need for base station infrastructure by being able to self-organized and self-configuring. Hence it provides a spontaneous and yet robust wireless communication systems. Initially, MANETs researchers were focused mainly on designing distributed and dynamic communications protocols for shared channel and for route discovery. It offers best-effort protocols to ensure optimum network operation in an unpredictable wireless environment. Additionally it maintained a network topology view and routes in the face of disruption of links, failure mobile devices and short residual connectivity time. Nonetheless one could not actually experienced any successful practical implementation of MANETs in the real world. Entertainment and some other multimedia services usually made an impact on any technological breakthrough but the potential of MANETs are not truly realized. They must be able to deliver such services, for which besteffort protocols are not adequate. This is because multimedia applications often have stringent delay and reliability sensitive service requirements. Subsequently, the research focus has shifted from best-effort services to the provision of better defined QoS in MANET. QoS routing protocols then play an essential role in a QoS mechanism, since it is their task to find which nodes, if any, can serve an application's requirements. It plays a major part in session admission control (SAC), due to its dependence on the route discovery that support the requested QoS. Alternatively, some QoS routing solutions may not attempt to serve applications' requirements directly, rather to improve QoS under a particular metrics. Most of the solutions proposed in the literature, until now have focused on providing QoS based on throughput and delay. Throughput is the most common metric used. This is due to its character as the lowest common denominator requirement. It is noted that, most voice or video applications require some level of guaranteed throughput in addition to their other constraints. However, many other useful metrics are also used to quantify QoS. In this work we cover most of them and provide examples of their use. The remainder of this article is structured as follows. In Section 2 we discuss related work in terms of QoS routing surveys and summarize their main points. Section 3 describes the problem statement of QoS routing. Section 4 explains in detail the existing heuristics of QoS routing protocol. Section 5 describes a brief review of the challenges posed by the provision of QoS on the MANET environment. Section 6 presents the factors that need to be considered in designing a viable QoS routing protocol, QoS routing protocol performance, the network resources consumable