On Multiuser Switched Diversity Transmission for Spectrum Sharing Systems
In this paper, the authors develop multiuser access schemes for spectrum sharing systems whereby secondary users share the spectrum with primary users. In particular, they devise two schemes for selecting the user among those that satisfy the interference constraints and achieve an acceptable Signal-to-Noise Ratio (SNR) level. The first scheme selects the user with the maximum SNR at the receiver, whereas in the second scheme the users are scanned in a sequential manner until an acceptable user is found. In addition, they consider two power adaptive settings. In the on/off power adaptive setting, the users transmit based on whether the interference constraint is met or not while in the full power adaptive setting, the users vary their transmission power to satisfy the interference constraint.