The capacity region of classes of product broadcast channels

Abstract

We establish a new outer bound for the capacity region of product broadcast channels. This outer bound matches Marton's inner bound for a variety of classes of product broadcast channels whose capacity regions were previously unknown. These classes include product of reversely semi-deterministic and product of reversely more-capable channels. A significant consequence of this new outer bound is that it establishes, via an example, that the previously best known outer-bound is strictly suboptimal for the general broadcast channel. Our example is comprised of a product broadcast channel with two semi-deterministic components in reverse orientation.

full version of the ISIT paper that is published in the Transactions of Information Theory. This revision fixes an incorrect channel diagram in Figure 2. The calculations in the original version were correct, but corresponded to the channel depicted in this version