Joint Bandwidth and Power Allocation for MIMO Two-Way Relays-Assisted Overlay Cognitive Radio Systems

Ahmad Alsharoa, Hakim Ghazzai, Elias Yaacoub, Mohamed-Slim Alouini, Ahmed Kamal

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


This paper studies the achievable cognitive sum rate of an overlay cognitive radio (CR) system assisted with multiple antennas two-way relays in which primary users (PUs) cooperate with cognitive users (CUs) for mutual benefits. In this context, the problem of both bandwidth and power allocation is investigated. We propose that the CUs are allowed to allocate a part of the PUs spectrum to perform their cognitive transmission. In return, acting as amplify-and-forward two-way relays, they are exploited to support PUs to reach their target data rates over the remaining bandwidth. Power expressions for optimal transmit power allocated per PU and CU antenna are derived under primary quality-of-service constraint in addition to bandwidth and power budget constraints. More specifically, CUs act as relays for the PUs transmission and gain some spectrum as long as they respect these constraints. After deriving the optimal transmit powers, we employ a strong optimization tool based on swarm intelligence to optimize the full and complex relay amplification gain matrices in addition to the bandwidths released to primary and cognitive transmission. Furthermore, three different utility functions are considered in our optimization problems depending on the level of fairness among CUs.
Original languageEnglish (US)
Pages (from-to)383-393
Number of pages11
JournalIEEE Transactions on Cognitive Communications and Networking
Issue number4
StatePublished - Oct 8 2015

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01


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