State of the Cognitive Interference Channel: A New Unified Inner Bound

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The capacity region of the interference channel in which one transmitter non-causally knows the message of the other, termed the cognitive interference channel, has remained open since its inception in 2005. A number of subtly differing achievable rate regions and outer bounds have been derived, some of which are tight under specific conditions. In this paper, the authors present a new unified inner bound for the discrete memoryless cognitive interference channel. They show explicitly how it encompasses all known discrete memoryless achievable rate regions as special cases. The presented achievable region was recently used in deriving the capacity region of the linear high-SNR deterministic approximation of the Gaussian cognitive interference channel.