Delay Optimal Scheduling for Chunked Random Linear Network Coding Broadcast

TL;DR

This paper analyzes the optimal scheduling of chunked Random Linear Network Coding for broadcast, demonstrating the optimality of the Least Received policy and refining key performance metrics under delay constraints.

Contribution

It proves the optimality of the LR scheduling policy for chunked RLNC in broadcast scenarios and refines related performance bounds and parameters.

Findings

LR policy is optimal for expected file transfer time

Refined bounds on transfer completion time and coding window size

Experimental validation with reduced feedback settings

Abstract

We study the broadcast transmission of a single file to an arbitrary number of receivers using Random Linear Network Coding (RLNC) in a network with unreliable channels. Due to the increased computational complexity of the decoding process (especially for large files) we apply chunked RLNC (i.e. RLNC is applied within non-overlapping subsets of the file). In our work we show the optimality of the Least Received (LR) batch scheduling policy (which was introduced in our prior work) with regards to the expected file transfer completion time. Furthermore, we refine some of our earlier results, namely the expected file transfer completion time of the LR policy and the minimum achievable coding window size in the case of a user defined delay constraint. Finally, we experimentally evaluate a modification of the LR policy in a more realistic system setting with reduced feedback from the receivers.