Proof-of-Concept System for Opportunistic Spectrum Access in Multi-user Decentralized Networks

Abstract

Poor utilization of an electromagnetic spectrum and ever increasing demand for spectrum have led to surge of interests in opportunistic spectrum access (OSA) based paradigms like cognitive radio and unlicensed LTE. In OSA for decentralized networks, frequency band selection from wideband spectrum is a challenging task since secondary users (SUs) do not share any information with each other. In this paper, a new decision making policy (DMP) has been proposed for OSA in the multi-user decentralized networks. First contribution is an accurate characterization of frequency bands using Bayes-UCB algorithm. Then, a novel SU orthogonization scheme using Bayes-UCB algorithm is proposed replacing randomization based scheme. At the end, USRP testbed has been developed for analyzing the performance of DMPs using real radio signals. Experimental results show that the proposed DMP offers significant improvement in spectrum utilization, fewer subband switching and collisions compared to other DMPs.

Keywords

• Cognitive radio
• opportunistic spectrum access
• online learning algorithm
• USRP testbed