The causal cognitive interference channel
Shraga I. Bross, Yossef Steinberg, Stephan Tinguely
Abstract
The (non-causal) cognitive interference channel, studied recently by Liang et.al., is a model for a classical twouser discrete memoryless interference channel, over which two transmitters send a pair of independent messages.It is assumed that the first message is shared by both encoders, whereas the second message in known only to Encoder 2 -the cognitive transmitter.Receiver 2 needs to decode both messages, and Receiver 1 should decode only the first message while Message 2 should be kept as secret as possible from Receiver 1.The level of secrecy is measured by the equivocation rate.For this model the capacity-equivocation region has been derived by Liang et.al..In this work we dispense of the assumption that Message 1 is shared a-priori by both encoders.Instead, we study the case in which Encoder 2 cribs causally from Encoder 1.We derive an achievable rate-equivocation region for this model and establish the capacity-equivocation region for a degraded interference channel.