Abstract
Cognitive radio (CR) technology enables the opportunistic use of the vacant licensed fre-quency bands, thereby improving the spectrum utilization. Cooperative communication is another promising technique that it can increase the capacity of relay links, and also brings some benefits in wireless networks. Recently, most of researches applying cooperative com-munications in CR networks are on infrastructure communications. Therefore, considering end-to-end throughput in CR ad-hoc networks is an important research issue because the availability of local spectrum resources may change frequently with the time and node loca-tions. In this thesis, we propose a cooperative routing protocol in CR ad-hoc networks. An on-demand routing protocol is used to find an end-to-end minimum cost path between a pair of source and destination. We define some performance metrics to estimate the maximum achievable capacity and transmission cost between two nodes with cooperative improvement via a relay. The simulation results show that our proposed cooperative routing protocol not only obtains higher end-to-end throughput, but also reduces the end-to-end delay and the amount of control messages compared to previous work.