Robust distributed cognitive relay beamforming

Ubaidulla Pandarakkottilil, Sonia Aissa

Research output: Chapter in Book/Report/Conference proceedingConference contribution

10 Scopus citations


In this paper, we present a distributed relay beamformer design for a cognitive radio network in which a cognitive (or secondary) transmit node communicates with a secondary receive node assisted by a set of cognitive non-regenerative relays. The secondary nodes share the spectrum with a licensed primary user (PU) node, and each node is assumed to be equipped with a single transmit/receive antenna. The interference to the PU resulting from the transmission from the cognitive nodes is kept below a specified limit. The proposed robust cognitive relay beamformer design seeks to minimize the total relay transmit power while ensuring that the transceiver signal-to-interference- plus-noise ratio and PU interference constraints are satisfied. The proposed design takes into account a parameter of the error in the channel state information (CSI) to render the performance of the beamformer robust in the presence of imperfect CSI. Though the original problem is non-convex, we show that the proposed design can be reformulated as a tractable convex optimization problem that can be solved efficiently. Numerical results are provided and illustrate the performance of the proposed designs for different network operating conditions and parameters. © 2012 IEEE.
Original languageEnglish (US)
Title of host publication2012 IEEE 75th Vehicular Technology Conference (VTC Spring)
PublisherInstitute of Electrical and Electronics Engineers (IEEE)
ISBN (Print)9781467309905
StatePublished - May 2012


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