Capacity Region of Multiple Access Channel with States Known Noncausally at One Encoder and Only Strictly Causally at the Other Encoder

We consider a two-user state-dependent multiaccess channel in which the states of the channel are known non-causally to one of the encoders and only strictly causally to the other encoder. Both encoders transmit a common message and, in addition, the encoder that knows the states non-causally transmits an individual message. We find explicit characterizations of the capacity region of this communication model in both discrete memoryless and memoryless Gaussian cases. In particular the capacity region analysis demonstrates the utility of the knowledge of the states only strictly causally at the encoder that sends only the common message in general. More specifically, in the discrete memoryless setting we show that such a knowledge is beneficial and increases the capacity region in general. In the Gaussian setting, we show that such a knowledge does not help, and the capacity is same as if the states were completely unknown at the encoder that sends only the common message. Furthermore, we also study the special case in which the The material in this paper was presented in part at the IEEE International Symposium on Information Theory, Saint-Petersburg, Russia, August 2011. This work has been supported by the European Commission in the framework of the FP7 Network of Excellence in Wireless Communications (NEWCOM++). The work of S. Shamai has also been supported by the CORNET consortium. Abdellatif Zaidi is with Université Paris-Est Marne La Vallée, 77454 Marne la Vallée Cedex 2, France. Email: [email protected] Pablo Piantanida is with the Department of Telecommunications, SUPELEC, 91190 Gif-sur-Yvette, France. Email: [email protected] Shlomo Shamai is with the Department of Electrical Engineering, Technion Institute of Technology, Technion City, Haifa 32000, Israel. Email: [email protected] December 21, 2013 DRAFT