Effective Delay Control in Online Network Coding

TL;DR

This paper develops online network coding algorithms that guarantee timely data delivery over erasure channels, improving delay performance by re-encoding strategies and uncoded packet transmissions.

Contribution

It introduces a new encoding framework that ensures delay guarantees in online network coding with perfect feedback and heterogeneous erasure probabilities.

Findings

Existing ARQ schemes fail for weak channels.

Re-encoding breaks unresolvable linear chains.

Uncoded packets at key times meet delay requirements.

Abstract

Motivated by streaming applications with stringent delay constraints, we consider the design of online network coding algorithms with timely delivery guarantees. Assuming that the sender is providing the same data to multiple receivers over independent packet erasure channels, we focus on the case of perfect feedback and heterogeneous erasure probabilities. Based on a general analytical framework for evaluating the decoding delay, we show that existing ARQ schemes fail to ensure that receivers with weak channels are able to recover from packet losses within reasonable time. To overcome this problem, we re-define the encoding rules in order to break the chains of linear combinations that cannot be decoded after one of the packets is lost. Our results show that sending uncoded packets at key times ensures that all the receivers are able to meet specific delay requirements with very high probability.