Abstracts Category : Other

Efficient Distributed Rendezvous Schemes And Spectrum Management For Cognitive Radio Networks

by Ji Li

Cognitive radio emerges as a technology to realize the dynamic spectrum access by dynamically configuring its transmission parameters. In a cognitive radio network (CRN), there are two types of users: primary users (PUs) and secondary users (SUs). PUs are the licensed users or the traditional wireless users who can access a specific licensed spectrum band. SUs are the unlicensed users equipped with cognitive radios that can opportunistically use currently unoccupied channels to transmit, but have to vacate channels for the returning PUs, and then switch to other available channels for continuous transmissions. When two SUs want to establish a link, they have to meet on the same channel that must be available for both of them simultaneously. This process is called <i>rendezvous.</i> Past research works on rendezvous only focused on designing the channel hopping sequence for the rendezvous process while ignoring some practical problems like rendezvous in wide-band CRNs, rendezvous without a predetermined sender and receiver, rendezvous considering directional antennas, and how to maximize the number of common available channels. In this dissertation, we propose five schemes to realize efficient rendezvous and spectrum management considering these practical problems under different scenarios. We first propose a rendezvous and communication framework for wide-band CRNs. Furthermore, we propose two efficient rendezvous schemes without predetermined sender and receiver. Moreover, we propose a rendezvous scheme specifically for SUs equipped with directional antennas. Last, we propose a power control protocol to maximize the number of common available channels. All of the proposed schemes can realize both efficient rendezvous and spectrum management with practical assumptions under different scenarios.