This book introduces cooperative spectrum sensing using OSTBC in order to achieve cooperative diversity in cognitive radio networks. Transmit diversity or gain is achieved by using cognitive relays between primary and cognitive controller. The signals received from the primary users are amplied by the cognitive relays and further forwarded to the cognitive controller where decisions are made on the basis of the information collected from each cognitive relay. The cooperative relaying protocol used here in cognitive relays is based on an amplifying-forward scheme. The energy detector ...