Performance of dynamic spectrum access with opportunistic selection mechanisms

Performance of a dynamic spectrum access system is analyzed for the realistic case when several multiple-antenna secondary base-stations (SRBS) serving their own users exist in the operating region of the primary system. The primary and the secondary systems co-exist in a symbiotic frame-work so that one SRBS opportunistically shares the spectrum with the primary, while another relays the primary signal. The SRBSs employ antenna-selection and user-selection. The secondary systems are assumed to have a peak power constraint, and use peak interference control to limit interference to the PR. The secondary users may employ interference cancellation. It is demonstrated that increasing number of users improves performance at all SNRs, while increasing number of SRBSs improves performance at high SNRs. Interference cancellation is shown to improve performance at low SNR. Expressions are derived for the outage probability of the DSA system. Performance obtained by computer simulations matches with that predicted by the derived expressions.