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In mobile ad hoc networks (MANETs), the provision of quality of service (QoS) guarantees is much more challenging mainly due to node mobility and resource constraints. Therefore it is important that routing protocols incorporate QoS metrics in route finding and maintenance to support end-to-end QoS. The traditional AODV protocol seems less satisfactory in terms of routing data to end systems. Many revisions are done to the traditional AODV protocol to meet QoS challenges focused on bandwidth, end to end delay, Packet delivery ratio, energy and mechanism overheads. Hence , it becomes very necessary for MANETS to have an efficient routing and QoS mechanism to support various application. This article extensively and exclusively studies the issues involved with QoS routing and presents an overview and comparison of existing QoS based revisions done on AODV protocol, thus providing the reader with insight into their differences and allows to highlight trends in protocol design and identify areas for future research.

Attention in the region of Mobile Ad-hoc Network (MANET) is increasing because of its realistic applications and necessity of communication in mobile devices. A mobile ad hoc network consists of mobile self configuring wireless nodes and these nodes communicate between them without any centralized management. The dynamic characteristics of MANET, has made it fairly demanding to uphold connectivity and guarantee Quality of Service (QoS). The trust based routing is one way to form cooperation among nodes for performing an efficient routing between nodes. In this paper a trust and energy based AODV is presented where nodes are selected for routing based on its trust and energy value. Trust is calculated based on the nodes success and failure rate. Energy calculated based on consumed and remaining energy values. A threshold value is defined and nodes are preferred for routing only if its trust and energy levels are higher than threshold. The work is implemented and simulated on NS-2. The simulation results have shown improvement on QoS metrics when compared with traditional AODV and DSR.

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Cognitive Radio technology holds great promise in solving the problem of spectrum scarcity.A plethora of routing protocols exist for Cognitive Radio networks,however most of them relay on establishing an end-to-end path using a Common Control Channel.This paper focuses on scenarios where the Primary User traffic is very high and erratic and therefore trying to set up end-to-end paths is not feasible.A novel solution to this problem is proposed where the cognitive users form a Cognitive Delay Tolerant Network through a modification in the network stack.Well researched delay tolerant networking routing protocols designed for networks with unreliable links, configured for multiple channel can used for routing in high primary user traffic environments.Through extensive simulation we show the that proposed architecture provides very high delivery ratio (close to 1) in the presence of very high primary user traffic with negligible computational complexity and the absence of a common control channel. We also show that trying to rely on routing protocols that try to establish end to end paths such as Multi-Channel AODV is not feasible. The performance of Multi-Channel AODV and proposed architecture is compared and analyzed with bundle/packet delivery ratio, end-to-end delay and hop count as performance metrics.

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