On the Performance of Cognitive Underlay SIMO Networks over Equally Correlated Rayleigh Fading Channels

The performance of single-input multiple-output (SIMO) cognitive spectrum sharing networks with the presence of equally correlated Rayleigh fading channels is investigated. In particular, based on the truncated infinitive series of cumulative distribution function (CDF) and probability density function (PDF) of the end-to-end signal-to-noise ratios (SNRs), close-form expressions are provided for the system outage performance, bit error rate and ergodic capacity. It is shown that the system performance merely depends on the correlation coefficient between antennas. Monte-Carlo simulations are also contributed to confirm the accuracy of our analysis

HARQ Feedback in Spectrum Sharing Networks

This letter studies the throughput and the outage probability of spectrum sharing networks utilizing hybrid automatic repeat request (HARQ) feedback. We focus on the repetition time diversity and the incremental redundancy HARQ protocols where the results are obtained for both continuous and bursting communication models. The channel data transmission efficiency is investigated in the presence of both secondary user peak transmission power and primary user received interference power constraints. Finally, we evaluate the effect of secondary-primary channel state information imperfection on the performance of the secondary channel. Simulation results show that, while the throughput is not necessarily increased by HARQ, substantial outage probability reduction is achieved in all conditions.Comment: Published in IEEE Communications Letter