Full duplex cognitive radio: a new design paradigm for enhancing spectrum usage



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IEEE Communications Magazine


With the rapid growth of demand for ever increasing data rates, spectrum resources have become more and more scarce. As a promising technique to increase the efficiency of the spectrum utilization, cognitive radio has great potential to meet such a requirement by allowing unlicensed users to coexist in licensed bands. In conventional CR systems, spectrum sensing is performed at the beginning of each time slot before data transmission. Unfortunately, this results in two major problems: transmission time reduction due to sensing, and sensing accuracy impairment due to data transmission. To tackle these problems, in this article we present a new design paradigm for future CR by exploring full duplex techniques to achieve simultaneous spectrum sensing and data transmission. With FD radios equipped at secondary users (SUs), the SUs can simultaneously sense and access the vacant spectrum, and thus significantly improve sensing performance while increasing data transmission efficiency. The aim of this article is to transform the promising conceptual framework into a practical wireless network design by addressing a diverse set of challenges such as protocol design and theoretical analysis. Several application scenarios with FD-enabled CR are elaborated, and key open research directions and novel algorithms in these systems are discussed.



Full duplex communication, Cognitive radio, Throughput, Relays, Data communication, Interference, Transmitting antennas


Copyright 2015 IEEE Communications Magazine. This is a pre-print version of a published paper that is available at: https://ieeexplore.ieee.org/abstract/document/7105652. Recommended citation: Liao, Yun, Lingyang Song, Zhu Han, and Yonghui Li. "Full duplex cognitive radio: a new design paradigm for enhancing spectrum usage." IEEE Communications Magazine 53, no. 5 (2015): 138-145. doi: 10.1109/MCOM.2015.7105652. This item has been deposited in accordance with publisher copyright and licensing terms and with the author's permission.