Capacity for Spectrum Sharing Cognitive Radios with MRC Diversity at the Secondary Receiver under Asymmetric Fading

In this paper we study the capacity of spectrum sharing cognitive radios (CR) with Maximal Ratio Combining (MRC) diversity at the secondary receiver under asymmetric fading, where the channel from secondary transmitter to primary receiver suffer Nakagami-m fading while the one from secondary transmitter to its receiver follows Rayleigh Multipath fading. Our mathematical analysis and numerical results show that with MRC combining diversity at the secondary receiver, more capacity is achieved. In addition, when the SU_tx-PU_rx channel has less severe fading which strongly affects the capacity of CR channel, utilizing MRC combining technique for CR system could reduce the effects.