A performance evaluation of cognitive radio networks with multi-antenna

In this paper, we consider a multi-antenna technique employed in cognitive radio networks for interference cancellation. A secondary user is equipped with a multi-antenna which will direct its available power in a direction that the interference to the primary user will be canceled. With this technique, the secondary user could transmit at anytime without generating harmful interference to the primary user. If the channel is idle, the secondary user may transmit with the full power, otherwise the secondary user has to allocate part of its available power for interference cancellation. As a result, the secondary user has dual transmission rate depending on whether the channel is busy or idle. The analysis and simulation results show that with multi antenna, the packet delay of the secondary user may be reduced significantly from that with single-antenna in which the secondary user is only allowed to transmit when the channel is idle.