Development of robust and fault-tolerant routing protocols for cognitive radio ad hoc networks /lcby Zamree Che-Aron
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 unlicense...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
Kuala Lumpur :
Kulliyyah of Engineering, International Islamic University Malaysia,
2015
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| Subjects: | |
| Online Access: | Click here to view 1st 24 pages of the thesis. Members can view fulltext at the specified PCs in the library. |
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| Summary: | 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. |
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| Physical Description: | xvii, 212 leaves : ill. ; 30cm. |
| Bibliography: | Includes bibliographical references (leaves 155-159). |