Cognitive aspects in a Multiple Access Channel

This paper is eligible for the student paper award. This paper is classified under Information Theory. In this paper, we investigate a three-user cognitive communication network where a primary two-user Multiple Access Channel (MAC) suffers interference from a secondary point-to-point channel, sharing the same medium. While the secondary channel transmitter causes an interference at the primary MAC receiver, we assume that the primary channel transmitters do not cause any interference at the secondary receiver. It is assumed that one of the primary transmitters has cognitive capabilities and cribs causally from the other MAC transmitter. Furthermore, we assume that the cognitive transmitter knows the message of the secondary transmitter in a non-causal manner and we introduce three-user Multiple Access Cognitive Z-Interference Channel (MA-CZIC). We obtain inner and outer bounds on the capacity region of the three-user MA-CZIC for both strictly and non-strictly causal cribbing cognitive encoders.