Energy-Efficient Design and Optimization of Wireline Access Networks

TL;DR

This paper formalizes the design and optimization of energy-efficient wireline access networks, proposing optimal solutions for transforming existing copper networks and heuristic methods for green-field deployments to minimize power consumption.

Contribution

It introduces a formal optimization framework for remote DSLAM placement, including polynomial-time solutions for existing networks and heuristic approaches for new deployments.

Findings

Optimal solutions for transforming copper to fiber-copper networks.

NP-complete nature of access network layout and placement problem.

Heuristic approach achieves near-optimal power and cost savings.

Abstract

Access networks, in particular, Digital Subscriber Line (DSL) equipment, are a significant source of energy consumption for wireline operators. Replacing large monolithic DSLAMs with smaller remote DSLAM units closer to customers can reduce the energy consumption as well as increase the reach of the access network. This paper attempts to formalize the design and optimization of the "last mile" wireline access network with energy as one of the costs to be minimized. In particular, the placement of remote DSLAM units needs to be optimized. We propose solutions for two scenarios. For the scenario where an existing all-copper network from the central office to the customers is to be transformed into a fiber-copper network with remote DSLAM units, we present optimal polynomial-time solutions. In the green-field scenario, both the access network layout and the placement of remote DSLAM units must be determined. We show that this problem is NP-complete. We present an optimal ILP formulation and also design an efficient heuristic-based approach to build a power-and-cost-optimized access network. Our heuristic-based approach yields results that are very close to optimal. We show how the power consumption of the access network can be reduced by carefully laying the access network and introducing remote DSLAM units.