A Linear Network Code Construction for General Integer Connections Based on the Constraint Satisfaction Problem

TL;DR

This paper introduces a linear network coding construction for general integer connections using constraint satisfaction problems, enabling distributed implementation and resource minimization in capacity-constrained networks.

Contribution

It generalizes random linear network coding for multicast to broader connections and proposes distributed algorithms with convergence guarantees.

Findings

Distributed algorithms achieve near-optimal resource minimization.

Approach outperforms existing methods in numerical simulations.

Guarantees no greater cost than traditional routing.

Abstract

The problem of finding network codes for general connections is inherently difficult in capacity constrained networks. Resource minimization for general connections with network coding is further complicated. Existing methods for identifying solutions mainly rely on highly restricted classes of network codes, and are almost all centralized. In this paper, we introduce linear network mixing coefficients for code constructions of general connections that generalize random linear network coding (RLNC) for multicast connections. For such code constructions, we pose the problem of cost minimization for the subgraph involved in the coding solution and relate this minimization to a path-based Constraint Satisfaction Problem (CSP) and an edge-based CSP. While CSPs are NP-complete in general, we present a path-based probabilistic distributed algorithm and an edge-based probabilistic distributed algorithm with almost sure convergence in finite time by applying Communication Free Learning (CFL). Our approach allows fairly general coding across flows, guarantees no greater cost than routing, and shows a possible distributed implementation. Numerical results illustrate the performance improvement of our approach over existing methods.