The Capacity Region of the Broadcast Channel with Non-Signaling Assistance
arXiv:2607.27434
The paper determines the exact set of achievable communication rates for a K‑user discrete memoryless broadcast channel when the transmitter and all receivers can use non‑signaling correlations, showing it matches Sato’s classic sum‑rate bound region.
Abstract
The capacity region of the -user discrete memoryless broadcast channel is fully characterized when non-signaling (NS) assistance is available to the transmitter and all receivers. The NS-assisted capacity region is shown to coincide with Sato's region, i.e., the region defined by sum-rate bounds over all subsets of messages, where each bound corresponds to full cooperation among that subset of receivers under a worst-case joint channel law consistent with the marginal channels.