A new outer bound on the capacity region of a class of Z-interference channels

Following the work of Liu and Goldsmith in 2009, we study a class of Z-interference channels that satisfy the shift-invariant condition but not the maximum entropy condition. We provide a new capacity region outer bound for this class of Z-interference channels. We show the tightness of the proposed outer bound by finding the capacity region of certain Z-interference channels which were not previously known.