Capacity region of a class of Gaussian cognitive degraded broadcast channel

This paper studies the cognitive broadcast channel in which the primary user communicates to the primary receiver, while the secondary user has noncausal knowledge of the primary radio´s codeword and expects to communicate to two secondary receivers. Comparing with the existing cognitive radio channel which considers only one secondary receiver, cognitive broadcast channel studies the case that there are multiple secondary receivers. To this end, we investigate the fundamental limits of the performance of the Gaussian cognitive broadcast channel from the information theoretic perspective. Specifically, we derive the capacity region of the Gaussian cognitive degraded broadcast channel with weak interference.