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Modeling Time-Varying Aggregate Interference in Cognitive Radio Systems, and Application to Primary Exclusive Zone Design

Ali, Mohd Shabbir and Mehta, Neelesh B (2014) Modeling Time-Varying Aggregate Interference in Cognitive Radio Systems, and Application to Primary Exclusive Zone Design. In: IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, 13 (1). pp. 429-439.

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Official URL: http://dx.doi.org/10.1109/TWC.2013.113013.130762


Accurately characterizing the time-varying interference caused to the primary users is essential in ensuring a successful deployment of cognitive radios (CR). We show that the aggregate interference at the primary receiver (PU-Rx) from multiple, randomly located cognitive users (CUs) is well modeled as a shifted lognormal random process, which is more accurate than the lognormal and the Gaussian process models considered in the literature, even for a relatively dense deployment of CUs. It also compares favorably with the asymptotically exact stable and symmetric truncated stable distribution models, except at high CU densities. Our model accounts for the effect of imperfect spectrum sensing, which depends on path-loss, shadowing, and small-scale fading of the link from the primary transmitter to the CU; the interweave and underlay modes or CR operation, which determine the transmit powers of the CUs; and time-correlated shadowing and fading of the links from the CUs to the PU-Rx. It leads to expressions for the probability distribution function, level crossing rate, and average exceedance duration. The impact of cooperative spectrum sensing is also characterized. We validate the model by applying it to redesign the primary exclusive zone to account for the time-varying nature of interference.

Item Type: Journal Article
Additional Information: copyright for this article belongs to IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA
Keywords: Cognitive radio; interference; spectrum sensing; underlay; interweave; shadowing; fading; time-variations; random process; lognormal; primary exclusive zone
Department/Centre: Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited: 19 Mar 2014 05:00
Last Modified: 19 Mar 2014 05:00
URI: http://eprints.iisc.ac.in/id/eprint/48645

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