Streaming Erasure Codes over Multi-Access Relayed Networks

TL;DR

This paper develops and analyzes streaming erasure codes for a multi-access relayed network with two sources, a relay, and a destination, optimizing data transmission under strict delay constraints.

Contribution

The paper introduces a novel framework for streaming codes in multi-access relayed networks, including two schemes that improve achievable rate regions and establish optimality conditions.

Findings

Achievable rate region derived with a closed-form expression.

Proposed schemes outperform baseline single-user codes.

Conditions identified when the first scheme is optimal.

Abstract

Many emerging multimedia streaming applications involve multiple users communicating under strict latency constraints. In this paper we study streaming codes for a network involving two source nodes, one relay node and a destination node. In our setting, each source node transmits a stream of messages, through the relay, to a destination, who is required to decode the messages under a strict delay constraint. For the case of a single source node, a class of streaming codes has been proposed by Fong et al. [2], using the concept of {\em delay-spectrum}. In the present work we present an in-depth analysis of the properties of delay-spectrum and apply them to develop streaming codes for our proposed setting through a novel framework. Our first scheme involves greedily selecting the rate on the link from relay to destination and using properties of the delay-spectrum to find feasible streaming codes that satisfy the required delay constraints. We provide a closed form expression for the achievable rate region and identify conditions when the proposed scheme is optimal by establishing a natural outer bound. Our second scheme builds upon this approach, but uses a numerical optimization-based approach to improve the achievable rate region over the first scheme. We demonstrate that our proposed schemes achieve significant improvements over baseline schemes based on single-user codes.