Cross-layer design of multi-hop wireless networks

MULTI -hop wireless networks are usually defined as a collection of nodes equipped with radio transmitters, which not only have the capability to communicate each other in a multi-hop fashion, but also to route each others’ data packets. The distributed nature of such networks makes them suitable for a variety of applications where there are no assumed reliable central entities, or controllers, and may significantly improve the scalability issues of conventional single-hop wireless networks. This Ph.D. dissertation mainly investigates two aspects of the research issues related to the efficient multi-hop wireless networks design, namely: (a) network protocols and (b) network management, both in cross-layer design paradigms to ensure the notion of service quality, such as quality of service (QoS) in wireless mesh networks (WMNs) for backhaul applications and quality of information (QoI) in wireless sensor networks (WSNs) for sensing tasks. Throughout the presentation of this Ph.D. dissertation, different network settings are used as illustrative examples, however the proposed algorithms, methodologies, protocols, and models are not restricted in the considered networks, but rather have wide applicability. First, this dissertation proposes a cross-layer design framework integrating a distributed proportional-fair scheduler and a QoS routing algorithm, while using WMNs as an illustrative example. The proposed approach has significant performance gain compared with other network protocols. Second, this dissertation proposes a generic admission control methodology for any packet network, wired and wireless, by modeling the network as a black box, and using a generic mathematical 0. Abstract 3 function and Taylor expansion to capture the admission impact. Third, this dissertation further enhances the previous designs by proposing a negotiation process, to bridge the applications’ service quality demands and the resource management, while using WSNs as an illustrative example. This approach allows the negotiation among different service classes and WSN resource allocations to reach the optimal operational status. Finally, the guarantees of the service quality are extended to the environment of multiple, disconnected, mobile subnetworks, where the question of how to maintain communications using dynamically controlled, unmanned data ferries is investigated

QoS in Node-disjoint Routing for Ad Hoc Networks

PhDA mobile ad hoc network (MANET) is a collection of mobile nodes that can communicate with each other without using any fixed infrastructure. It is necessary for MANETs to have efficient routing protocol and quality of service (QoS) mechanism to support multimedia applications such as video and voice. Node-Disjoint Multipath Routing Protocol (NDMR) is a practical protocol in MANETs: it reduces routing overhead dramatically and achieves multiple node-disjoint routing paths. Because QoS support in MANETs is important as best-effort routing is not efficient for supporting multimedia applications, this thesis presents a novel approach to provide that support. In this thesis NDMR is enhanced to provide a QoS enabled NDMR that decreases the transmission delay between source and destination nodes. A multi-rate mechanism is also implemented in the new protocol so that the NDMR QoS can minimise the overall delays. It is shown that these approaches lead to significant performance gains. A modification to NDMR is also proposed to overcome some of the limitations of the original

Multipath optimized link state routing for mobile ad hoc networks

International audienceMultipath routing protocols for Mobile Ad hoc NETwork (MANET) address the problem of scalability, security (confidentiality and integrity), lifetime of networks, instability of wireless transmissions, and their adaptation to applications. Our protocol, called MP-OLSR (MultiPath OLSR), is a multipath routing protocol based on OLSR. The Multipath Dijkstra Algorithm is proposed to obtain multiple paths. The algorithm gains great flexibility and extensibility by employing different link metrics and cost functions. In addition, route recovery and loop detection are implemented in MP-OLSR in order to improve quality of service regarding OLSR. The backward compatibility with OLSR based on IP source routing is also studied. Simulation based on Qualnet simulator is performed in different scenarios. A testbed is also set up to validate the protocol in real world. The results reveal that MP-OLSR is suitable for mobile, large and dense networks with large traffic, and could satisfy critical multimedia applications with high on time constraints

Improving routing performance of multipath ad hoc on-demand distance vector in mobile add hoc networks.

The aim of this research is to improve routing fault tolerance in Mobile Ad hoc Networks (MANETs) by optimising mUltipath routing in a well-studied reactive and single path routing protocol known as Ad hoc On-demand Distance Vector (AODV). The research also aims to prove the effect of varying waiting time of Route Reply (RREP) procedure and utilising the concept of efficient routes on the performance of multipath extensions to AODV. Two novel multipath routing approaches are developed in this thesis as new extensions to AODV to optimise routing overhead by improving Route Discovery Process (RDP) and Route Maintenance Process (RMP) of multipath AODV. The first approach is a Iinkdisjoint multipath extension called 'Thresho)d efficient Routes in multipath AODV' (TRAODV) that optimises routing packets ~verhead by improving the RDP of AODV which is achieved by detecting the waiting time required for RREP procedure to receive a threshold number of efficient routes. The second approach is also a link-disjoint mUltipath extension called 'On-demand Route maintenance in Multipath AoDv' (ORMAD) which is an extension to TRAODV that optimises routing packets and delay overhead by improving the RMP of TRAODV. ORMAD applies the concepts of threshold waiting time and efficient routes to both phases RDP and RMP. It also applies RMP only to efficient routes which are selected in the RDP and when a route fails, it invokes a local repair procedure between upstream and downstream nodes of the broken link. This mechanism produces a set of alternative subroutes with less number of hops which enhances route efficiency and consequently minimises the routing overhead. TRAODV and ORMAD are implemented and evaluated against two existing multipath extensions to,AODV protocol and two traditional multipath protocols. The existing extensions to AODV used in the evaluation are a well-known protocol called Ad hoc On-demand Multipath Distance Vector (AOMDV) and a recent extension called Multiple Route AODV (MRAODV) protocol which is extended in this thesis to the new approach TRAODV while the traditional multipath protocols used in the evaluation are Dynamic Source Routing (DSR) and Temporally Ordered Routing Algorithm (TORA). Protocols are implemented using NS2 and evaluated under the same simulation environment in terms of four performance metrics; packet delivery fraction, average end-to-end delay, routing packets overhead, and throughput. Simulation results of TRAODV evaluation show that the average number of routes stored in a routing table of MRAODV protocol is always larger than the average number of routes in TRAODV. Simulation results show that TRAODV reduces the overall routing packets overhead compared to both extensions AOMDV and MRAODV, especially for large network size and high mobility. A vital drawback of TRAODV is that its performance is reduced compared to AOMDV and MRAODV in terms of average end-to-end delay. Additionally, TORA still outperforms TRAODV and the other extensions to AODV in terms of routing packets overhead. In order to overcome the drawbacks of TRAODV, ORMAD is developed by improving the RDP of TRAODV. The performance of ORMAD is evaluated against RREP waiting time using the idea of utilising the efficient routes in both phases RDP and RMP. Simulation results of ORMAD show that the performance is affected by varying the two RREP waiting times of both RDP and RMP in different scenarios. As shown by the simulation results, applying the short and long waiting times in both phases tends to less performance in terms of routing packets overhead while applying the moderate waiting times tends to better performance. ORMAD enhances routing packets overhead and the average end-to-end delay compared to TRAODV, especially in high mobility scenarios. ORMAD has the closest performance to TORA protocol in terms of routing packets overhead compared to ~M~a~M~OW . Relevant concepts are formalised for ORMAD approach and conducted as an analytical model in this thesis involving the\vhole process of multipath routing in AODV extensions. ORMAD analytical model describes how the two phases RDP and RMP interact with each other with regard to two performance metrics; total number of detected routes and Route Efficiency.EThOS - Electronic Theses Online ServiceGBUnited Kingdo