On the capacity region of the degraded Z channel

In this paper, we consider the two-user Z Channel (ZC). There are two senders and two receivers in the model. One of the senders transmits information to its intended receiver, while the other sender transmits information to both receivers. We establish a new achievable rate region for the ZC, using Marton´s binning technique. At the receivers, we use joint decoding strategy. To illustrate the tightness of the proposed inner bound, we consider the degraded ZC which was first introduced by Chong et. al. We then characterize the capacity region of this type of degraded ZC.