Alex Leith

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—Feedback delay can severely affect the performance of transmit beamforming (TB) and the analytical quantification of the performance degradation has attracted much research interest recently. In this letter, we study the effect of delayed and limited-rate codebook index feedback on the error rate performance of TB systems over Rayleigh fading channels. We(More)
— In this paper, we study the weighted sum rate maximization of multicell cellular cognitive radio networks (CRNs) which are overlaid with multicell primary radio networks (PRNs). We assume each CRN cell is collocated with a PRN cell and has a cellular structure with access point (AP) and multiple secondary users (SUs). We propose a unified framework to(More)
—In this paper, we study the sum-rate maximization algorithms for downlink and uplink orthogonal frequency division multiple access (OFDMA) systems under proportional-rate constraint (PRC) and minimum-rate constraint. We develop a low-complexity weighted channel signal-to-noise ratio (w-SNR)-based ranking scheme for user selection on each subchannel in(More)
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