Accessing the hidden available spectrum in cognitive radio networks under GSM-based primary networks

Abstract

The Global System for Mobile Communications (GSM) system is generally considered to be one of the most successful cellular standards. However, in the cognitive radio (CR) research community, the GSM system is rarely considered as the primary network. Because of the popularity and the significance of GSM, in this paper, we investigate the spectrum access issue in CR networks under GSM-based primary networks. One unique novelty of this paper is that the special features of the GSM system (i.e., frequency division duplex (FDD) and time division multiple access (TDMA)) are simultaneously considered and utilized to further enhance the spectrum access performance of CR networks. By incorporating the location information, a novel dynamic spectrum access scheme is proposed to access the available spectrum vacancies which are usually hidden by traditional schemes. In addition, a queuing model is designed to analyze the network performance as well as to optimize system parameters. Extensive simulation results show that the proposed dynamic spectrum access scheme outperforms the traditional scheme in terms of higher throughput. To the best of our knowledge, this is the first paper that simultaneously utilizes the TDMA and FDD features to enhance the spectrum access performance in CR networks.