New Protocol for QoS Routing in Mobile Ad-Hoc Networks by ProQuest


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International Journal of Communication Networks and Information Security (IJCNIS)                          Vol. 1, No. 3, December 2009

   New Protocol for QoS Routing in Mobile Ad-Hoc
                                                  *Shahid Mumtaz, Alitio Gamerio
                                                       University of Aveiro, Portugal

   Abstract— Provision of quality of service (QoS) in an ad hoc         uncorrelated so as to have the maximum usage in terms of
network is a challenging task. The challenge comes due the inherent     throughput and bandwidth utilization. However, identifying
characteristics of mobile ad hoc networks. In this paper, we describe   multiple node disjoint paths that are uncorrelated or
the provision of QoS using node-disjoint multipath routing. We          independent is a challenging task. In [1], it is pointed out that
discuss how one can have probabilistic QoS guarantees using a
                                                                        the problem of finding two node-disjoint paths that do not
protocol where nodes are aware of their neighbors that may
interfere while relaying packets to other nodes along the paths         interfere with one another in a connected network is NP-
towards the destination. We analyze the computational and               complete. The problem of finding the maximum number of
communication overheads incurred in identifying correlation aware       node-disjoint paths between a given source and a destination
multiple node-disjoint paths, and the probability that the packets      such that there are no cross links between nodes that belong
arrive at the destination before their respective deadlines.            to different paths has already been proved to be NP complete
                                                                        in [2].
   Keywords— Quality of service, node-disjoint multi-path routing,      In other words, one may not be able to identify not only the
path independence.                                                      maximum number of uncorrelated node-disjoint paths but
                                                                        also even two node-disjoint paths that are uncorrelated in a
1. Introduction                                                         reasonable amount of time. Finding multiple uncorrelated
An ad hoc network can be formed instantaneously enabling                node-disjoint paths between a given pair of nodes in an
the participants to communicate without the required                    adhoc network is the same as finding a chordless cycle in a
intervention of a centralized infrastructure or an access point.        graph that contains source and destination nodes [3]. The
Those who want to bypass the infrastructure for some                    later problem is an NP-complete problem [4]. Some
reasons and still want to communicate may form an ad hoc                specialized methods that use directional antennas to mitigate
network. An ad hoc network may provide cheaper and cost-                path correlation among node-disjoint paths are described in
effective ways to share information among many mobile                   [5]. In [7], the maximum flow problem is formulated as an
hosts. Some of the characteristics of an ad hoc network                 optimization problem using switched beam directional
differentiate it from other classes of wired and wireless               antenna for sensor networks that have limited interference.
networks. In an ad hoc network, the transmission range of               How to select multiple paths based on channel aware
mobile devices is limited, therefore, routes are often                  multipath metric in mesh networks is described in [8]. An
multihop. There are no separate routers, therefore, nodes in            interference-aware metric for path selection for reliable
the network cooperate to forward packets of one another                 routing in wireless mesh networks is presented in [9]. An
towards their ultimate destinations. The devices used to form           interference-minimized multipath routing for high rate
such a network are often powered through batteries whose                streaming in wireless sensor networks is presented in [10]. In
power depletion may cause node failures. Further, nodes                 this paper, we propose a routing protocol that provides a
may move about randomly and therefore the topology of the               probabilistic QoS in mobile ad hoc networks. In our
network may vary dynamically. It is desirable to have a                 protocol, the ensuing data packets may flow through
provision of quality of service (QoS) in an ad hoc network.             multiple node disjoint paths, one along one path. However,
However, there are many peculiar characteristics of an ad               at each hop the service received by the packet depends upon
hoc network that hinder in providing QoS. For example, the              the following factors: how much bandwidth is available, how
absence of any centralized infrastructure and the                       urgent the packet is, and if assigned a higher priority whether
dynamically varying topology of a mobile ad hoc networks                the packet can meet the deadline till the destination. The rest
make the provision of quality of service (QoS) a c
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