New Results on the Capacity of the Gaussian Cognitive Interference Channel

The capacity of the two-user Gaussian cognitive interference channel, a variation of the classical interference channel where one of the transmitters has knowledge of both messages, is known in several parameter regimes but remains unknown in general. In this paper, the authors consider the following achievable scheme: the cognitive transmitter pre-codes its message against the interference created at its intended receiver by the primary user, and the cognitive receiver only decodes its intended message, similar to the optimal scheme for "Weak interference"; the primary decoder decodes both messages, similar to the optimal scheme for "Very strong interference".