Due to the rapid advancement of wireless technologies, the radio spectrum is one of the most heavily used and costly natural resources. Cognitive Radio (CR) has been proposed as a promising technology to solve the problem of radio spectrum shortage and spectrum underutilization by enabling unlicensed users to opportunistically access the available licensed bands for data communications in an intelligent and cautious manner. In Cognitive Radio Ad Hoc Networks (CRAHNs), which operate without centralized infrastructure support, the data routing is one of the most important issues to be taken into account and requires more studies. Moreover, in such networks, a path failure can easily occur during data transmission caused by an activity of licensed users, node mobility, node fault, or link degradation. Also, the network performance is severely degraded due to a large number of path failures. In addition, with the unique characteristics of CRAHNs, another main issue is related with the establishment of appropriate path for data transmission which does not cause harmful interference to PUs’ communications and reflects accurate path characteristics in order to improve network performance. In this thesis, the Fault-Tolerant Cognitive Ad-hoc Routing Protocol (FTCARP) is proposed to provide fast and efficient route recovery in presence of path failures during data delivery in CRAHNs. In FTCARP, a backup path is immediately utilized in case a failure occurs over a primary transmission route in order to transfer the next coming data packets without severe service disruption. The protocol uses different route recovery mechanism to handle different cause of a path failure. Besides, this thesis also proposes a robustness aware routing protocol for CRAHNs, referred to the Robustness Aware Cognitive Ad-hoc Routing Protocol (RACARP), with an aim to provide robust paths for data delivery. The Expected Path Delay (EPD) routing metric used for path decision is introduced and applied in the protocol. The metric takes account of the link delay and the effect of packet loss on wireless links. Furthermore, the protocol avoids creating a transmission path that uses Primary User (PU)’s channel in PU regions in order to counteract the impact of PU activities which can simply cause communication interruptions. Both proposed routing protocols jointly exploit path and spectrum diversity in routing process in order to provide multi-path and multi-channel routes. The performance evaluation is conducted through simulation using NS-2 simulator. The protocol performance is benchmarked against the Dual Diversity Cognitive Ad-hoc Routing Protocol (D2CARP). The simulation results prove that the FTCARP and RACARP protocol achieve better performance in terms of average throughput, percentage of packet loss, average end-to-end delay, and average jitter as compared to the D2CARP protocol. In the network with 7 path failures, the FTCARP protocol achieves a throughput enhancement of 13.51%, a packet loss enhancement of 97.16%, an end-to-end delay enhancement of 26.48% and a jitter enhancement of 82.53% over the D2CARP protocol. In the network with 14 data traffic connections, the RACARP protocol achieves a throughput enhancement of 15.19%, a packet loss enhancement of 79.15%, an end-to-end delay enhancement of 48.94%, and a jitter enhancement of 48.42% over the D2CARP protocol. However, the proposed routing protocols produce more routing overhead to the network compared to the D2CARP protocol.

The fast growing of the Internet applications and the need of the continuous ongoing connection brought new challenges for researchers to provide new solutions to guarantee the Internet access for mobile hosts and networks. The globally reachable, Home-Agent based, and infrastructure Network Mobility (NEMO) and the local, multi-hop, and infrastructure-less Mobile Ad hoc Network (MANET) developed by Internet Engineering Task Force (IETF) are supporting different topologies of the mobile networks. A new architecture was proposed to deal with the inefficiency of the Nested NEMOs as well as the global connectivity issues of MANET by combining both topologies to obtain Mobile Ad Hoc NEMO (MANEMO). However, the integration of NEMO and MANET introduces many challenges such as the redundant tunnel problem and Exit Router selection when multiple Exit Routers to the Internet exist. This research aims to propose MANEMO Gateway Discovery and Selection Scheme (MGDSS) which discovers and selects the gateway which improves the performance and the robustness of the network regardless of routing protocol used. This is done by extending the Tree Discovery Protocol (TDP) used by NEMO BSP and the Neighborhood Discovery protocol used by MANET. Every Mobile Router (MR) receives the information about all the Internet gateways in the network and selects the gateway based on multiple criteria: the hop count, the nested level, the stable time and the number of nodes registered at the intermediate nodes. The routing of packets in the MANEMO is proposed to be based on the selected gateway, as for NEMO gateway the tree structure will be used and for MANET gateway it depends on the routing protocol used. The OPNET Modeler 14.5 is used to evaluate the proposed scheme as well as the mathematical approach to benchmark with the standard NEMO BSP and the Multihomed MANEMO (M-MANEMO) approach. The results show that the average data packets dropped in WLAN connecting the MRs of the proposed scheme is 28.6% less compared to the NEMO BSP and 63% compared to the M-MANEMO. With fast mobility, the average WLAN delay of M-MANEMO is 14.3% more than the other two approaches. Also in a larger scale MANEMO with high traffic load and fast mobility, the MGDSS outperforms the M-MANEMO with reduced end-to-end delay around 21.6%. Whereas NEMO BSP has 68.7% more end-to-end delay compared to MGDSS. These delays cause the MGDSS to have 66.6% less voice jitter compared to M-MANEMO.

Mobile Ad hoc Networks (MANETs) have gained significant interest and popularity since they have enormous potential in several fields of applications. Infrastructure-free, self-configuring and mobility are the main reasons behind this popularity. As the necessity of the group-oriented applications over MANET increases, Quality of Service (QoS) support is getting attention as one of the critical issues. Multicast communication is the ideal communication technique for supporting these types of applications. However, QoS multicast routing in large-scale networks faces several difficulties and challenges that need to be addressed. These challenges include dynamic MANET topology, multicast packet forwarding and shared wireless medium. Thus, it is necessary to design an efficient multicast routing protocol to support multimedia multicast applications in large networks with large group sizes. In this research, the problem of scalability of multicast routing protocols to support QoS over MANETs is investigated. In particular, a new Scalable QOS Multicast Routing Protocol (SQMRP) has been developed. The main objective of this protocol is to design a lightweight scalable QoS multicast routing scheme irrespective of the number of multicast members and network size. This is achieved by applying the following strategies: First, designing a novel and scalable virtual architecture that takes advantage of the geometric information of the mobile nodes, which provides efficient cluster management to handle dynamic movement of mobile nodes. Second, developing a new location service algorithm which reduces redundant propagation of packets between clusters. Third, proposing a simple and efficient hierarchical structure to manage the multicast members to further enhance the scalability. And finally, setting up a multicast forwarding tree through developing a route discovery algorithm guided by the geographic information which incurs lower overhead. The performance of the proposed protocol is evaluated through developing both an analytical investigation and extensive simulation using the GloMoSim simulator environment. The obtained results are compared with the well-known multicast protocol On-Demand Multicast Routing Protocol (ODMRP). It has been found that the proposed virtual construction can scale to large MANETs and effectively reduces the communication overhead for location service and multicast routing discovery. The simulation results showed that, the average PDR of SQMRP is higher by 7.9% and the NPO is reduced by an average of 57.7% compared to ODMRP considering different network sizes. Also, PDR is improved by 8.3% and the NPO is reduced by 55.6% for different multicast group sizes. In fact, it is observed that SQMRP out performs ODMRP protocol in most of the studied metrics and scenarios.