Optimal Transmission Strategy and Explicit Capacity Region for Broadcast Z Channels

TL;DR

This paper derives an explicit capacity region for the two-user broadcast Z channel, showing that independent encoding and nonlinear turbo codes can achieve near-optimal performance with low complexity.

Contribution

It provides the first explicit expression for the capacity region of the broadcast Z channel and demonstrates that independent encoding achieves the optimal boundary.

Findings

Explicit capacity region derived for the two-user broadcast Z channel.

Independent encoding of users achieves the optimal boundary.

Nonlinear turbo codes enable low-complexity near-optimal transmission schemes.

Abstract

This paper provides an explicit expression for the capacity region of the two-user broadcast Z channel and proves that the optimal boundary can be achieved by independent encoding of each user. Specifically, the information messages corresponding to each user are encoded independently and the OR of these two encoded streams is transmitted. Nonlinear turbo codes that provide a controlled distribution of ones and zeros are used to demonstrate a low-complexity scheme that operates close to the optimal boundary.