Coexistence of Heterogeneous Cognitive Radio Systems

The purpose of this project is to establish how broadband terrestrial and HAPs systems should use the same spectral allocation in order to maximise system capacity and quality of service. Currently, in order to tightly control interference, most licensed spectrum is allocated to an operator on a geographical basis. This approach is inefficient due to its inflexibility. Over the last few years 'unlicensed' bands have become popular, where different operators and users share common spectrum provided they obey appropriate spectrum etiquettes, but this approach provides less control and restricts quality of service guarantees that can be given by operators for different applications.

WiMAX (IEEE 802.16a) has been proposed as the new way to deliver broadband for terrestrial non-line of sight, long-range systems, operating in 3-11GHz bands. The similarities between terrestrial and High Altitude Platform (HAP) systems also mean that it is a good candidate for delivering broadband from HAPs. To date much of the HAP broadband research has been restricted to the mm-wave bands, largely owing to regulatory constraints, but there is no fundamental reason why WiMAX should not be extended to HAP systems.

This project will examine a range of possibilities to allocate spectrum falling within these two extremes, using the WiMAX standard and parameters as a starting basis. The project will aim to show that dynamic spectrum sharing, and possibly more sophisticated cognitive radio techniques will provide the best approach. In this case spectrum will be allocated from a common pool to one or more of the services on a dynamic basis. Techniques based on game theory, coexistence etiquettes and bandwidth broker(s) will be examined. One option is to consider that the user "owns" the spectrum, rather than the operator, and understanding the benefits/drawbacks such an approach can bring.

This project will involve Monte Carlo simulation, using MATLAB and/or C and/or OPNET. As well as game theory, other possible analytical techniques could include queuing theory and set theory.

Project outputs

Dynamic spectrum sharing techniques based on game theory, spectrum etiquettes, bandwidth broker(s), using WiMAX as a basis
Simulation(s) illustrating the effects
Statistical distributions of performance for HAP and terrestrial systems
Conference (and contributions to journal) papers, and potentially reports to regulators

Coexistence of Heterogeneous Cognitive Radio Systems

Project outputs

Members

Dates

Research