Optimal Steerable mmWave Mesh Backhaul Reconfiguration

TL;DR

This paper presents a software-defined framework for optimally reconfiguring mmWave mesh backhaul networks in 5G, minimizing traffic disruption and packet loss during topology changes.

Contribution

It introduces a MILP-based model for optimal reconfiguration and backup path creation in steerable mmWave mesh backhaul networks, considering mechanical antenna alignment.

Findings

Increasing BH interfaces per SC reduces packet loss by over 50%.

More reconfiguration time allows for additional backup paths, lowering traffic impact.

The framework effectively minimizes traffic disruption during network reconfiguration.

Abstract

Future 5G mobile networks will require increased backhaul (BH) capacity to connect a massive amount of high capacity small cells (SCs) to the network. Because having an optical connection to each SC might be infeasible, mmWave-based (e.g. 60 GHz) BH links are an interesting alternative due to their large available bandwidth. To cope with the increased path loss, mmWave links require directional antennas that should be able to direct their beams to different neighbors, to dynamically change the BH topology, in case new nodes are powered on/off or the traffic demand has changed. Such BH adaptation needs to be orchestrated to minimize the impact on existing traffic. This paper develops a Software-defined networking-based framework that guides the optimal reconfiguration of mesh BH networks composed by mmWave links, where antennas need to be mechanically aligned. By modelling the problem as a Mixed Integer Linear Program (MILP), its solution returns the optimal ordering of events necessary to transition between two BH network configurations. The model creates backup paths whenever it is possible, while minimizing the packet loss of ongoing flows. A numerical evaluation with different topologies and traffic demands shows that increasing the number of BH interfaces per SC from 2 to 4 can decrease the total loss by more than 50%. Moreover, when increasing the total reconfiguration time, additional backup paths can be created, consequently reducing the reconfiguration impact on existing traffic.