Title: Dynamic Spectrum Access in heterogeneous unlicensed wireless networks

Authors: Jianhua He, Yan Zhang, Dritan Kaleshi, Alistair Munro, Joseph McGeehan

Addresses: Institute of Advanced Telecommunications, Swansea University, Wales, SA2 8PP, UK. ' Simula Research Laboratory, PO Box 134, 1325 Lysaker, Norway. ' Centre for Communications Research, Bristol University, Bristol, BS8 1UB, UK. ' Centre for Communications Research, Bristol University, Bristol, BS8 1UB, UK. ' Centre for Communications Research, Bristol University, Bristol, BS8 1UB, UK

Abstract: Existing wireless systems are normally regulated by a fixed spectrum assignment strategy. This policy leads to an undesirable situation that some systems may only use the allocated spectrum to a limited extent while others have very serious spectrum insufficiency situation. Dynamic Spectrum Access (DSA) is emerging as a promising technology to address this issue such that the unused licensed spectrum can be opportunistically accessed by the unlicensed users. To enable DSA, the unlicensed user shall have the capability of detecting the unoccupied spectrum, controlling its spectrum access in an adaptive manner, and coexisting with other unlicensed users automatically. In this article, we propose a radio system Transmission Opportunity-based spectrum access control protocol with the aim to improve spectrum access fairness and ensure safe coexistence of multiple heterogeneous unlicensed radio systems. In the scheme, multiple radio systems will coexist and dynamically use available free spectrum without interfering with licensed users. Simulation is carried out to evaluate the performance of the proposed scheme with respect to spectrum utilisation, fairness and scalability. Comparing with the existed studies, our strategy is able to achieve higher scalability and controllability without degrading spectrum utilisation and fairness performance.

Keywords: cognitive radio; dynamic spectrum access; DSA; unlicensed wireless networks; spectrum access control; simulation; spectrum utilisation; fairness; scalability.

DOI: 10.1504/IJAACS.2008.019204

International Journal of Autonomous and Adaptive Communications Systems, 2008 Vol.1 No.1, pp.148 - 163

Published online: 02 Jul 2008 *

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