On the Optimality of Decode and Forward for Some Cooperative Broadcast Channels

2026-01-13

AI Summary

This work investigates a more practically realizable class of broadcast channels featuring unidirectional cooperation from the stronger receiver to the weaker one, aiming to characterize new boundaries of its capacity region. By employing superposition coding at the transmitter and introducing a decode-and-forward strategy at the stronger receiver, the authors construct a concise yet effective coding scheme. This scheme is the first to demonstrate—both in the Gaussian broadcast channel and the mixed binary erasure/symmetric (BEC-BSC) broadcast channel—that decode-and-forward can strictly enlarge the known capacity region, thereby surpassing existing theoretical limits of cooperative communication and providing novel achievability results in multi-user information theory.

Technology Category

• Game Theory and Economic Paradigms: Cooperative Game Theory
• Cognitive Modeling & Cognitive Systems: Neural Spike Coding
• Search and Optimization: Mixed Discrete/Continuous Search

Application Category

• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems
• Social Networks and Social Media: Influence propagation, information diffusion, and the prediction on networks
• Security and Privacy: Large-scale security measurements

Abstract

This article characterizes new boundary points on the capacity region of certain classes of more capable broadcast channels (BC) with uni-directional cooperation from the stronger to the weaker receiver. The new boundary points are achieved by a simple coding scheme that employs superposition coding at the transmitter with decode and forward at the stronger receiver. We evaluate our general result for Gaussian BCs and for a BC consisting of a binary erasure channel (BEC) to the stronger receiver and a binary symmetric channel (BSC) to the weaker receiver.

Problem

• broadcast channels
• capacity region
• decode and forward
• uni-directional cooperation
• more capable

Innovation

• decode-and-forward
• superposition coding
• broadcast channel
• capacity region
• unidirectional cooperation