Uncoordinated beamforming for cognitive networks

Simon Yiu, Chan Byoung Chae, Kai Yang, Doru Calin

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


In this paper, we propose jointly-optimized beamforming algorithms for cognitive networks to maximize the achievable rates, where primary and cognitive users share the same spectrum and are equipped with multiple antennas. We consider the transmission of a single information stream in both primary and secondary links. No coordination is required between the primary and cognitive users and the interference cancellation is done at the cognitive user. Specifically, the beamforming vectors of the cognitive link are designed to maximize the achievable rate under the condition that the interference both at the primary and cognitive receivers is completely nullified. Furthermore, it is proved that the achievable rate of a general N C t × 2 (N t C transmit antennas at the cognitive transmitter and 2 receive antennas at the cognitive receiver) cognitive multiple-input multiple-output (MIMO) link employing the optimal proposed beamformers (which completely nullifies the interference to and from the primary link while maximizing its own achievable rate) is the same as the rate of an interference-free (N t C-1) × 1 multiple-input single-output (MISO) link employing an optimal maximal ratio transmission beamforming vector. The sum rate performance of the proposed algorithms is evaluated by Monte Carlo simulations. The impact of the number of transmit and receive antennas on the proposed algorithm is also discussed.

Original languageEnglish
Article number6168185
Pages (from-to)1390-1397
Number of pages8
JournalIEEE Transactions on Communications
Issue number5
Publication statusPublished - 2012 May

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering


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