Efficient resource allocation schemes for cognitive radio networks: agile spectrum sharing and enabling technologies

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In recent years, wireless applications have become increasingly crucial while the number of wireless users has constantly been growing. However, the radio spectrum is a scarce natural resource; and its majority is allocated to well-identified licensed users. In general, licensed users are unwilling to share their spectrum with other unknown users and a large part of the licensed spectrum is not fully utilised. Cognitive Radio (CR) technology (based on software defined radio) presents a practical approach to spectrum scarcity and to its underutilisation. This is achieved by implementing the concept of dynamic spectrum access such that unlicensed CR users can dynamically access the licensed spectrum, without causing harmful interference to licensed users. This research program focuses on developing original and innovative efficient resource allocation schemes for the integration of CR technology in emerging wireless networking techniques. First, we will investigate CR nodes operating with cooperative communication - that builds a virtual multi-antenna system by making use of the antennas available in the neighbour nodes. This integration creates a cognitive cooperative system where efficient resource allocation algorithms are critical for extracting the benefits of both the cognition and the cooperation. Second, we will study the integration of dynamic spectrum access into femtocell cellular systems. Femtocell systems provide a high-throughput high-mobility service to answer the more-challenging requirements of new wireless applications. Each femtocell contains one low-power low-cost high-throughput base station connected to the wide cellular network through a reliable high speed connection. Femtocell benefits can be significantly curtailed without efficient resource allocation, spectrum access and interference control schemes.