Robust Design of Spectrum-Sharing Networks

TL;DR

This paper addresses spectrum-sharing network reliability by optimizing backup channel assignments to minimize additional bandwidth needs, demonstrating that scalable solutions can be effective even as network size grows.

Contribution

It introduces a novel optimization framework for backup channel assignment in spectrum-sharing networks, including structural characterization and approximation algorithms.

Findings

Optimal assignment structure characterized

Bi-criteria approximation algorithms developed

Recovery capacity becomes negligible in large networks

Abstract

In spectrum-sharing networks, primary users have the right to preempt secondary users, which significantly degrades the performance of underlying secondary users. In this paper, we use backup channels to provide reliability guarantees for secondary users. In particular, we study the optimal white channel assignment that minimizes the amount of recovery capacity (i.e., bandwidth of backup channels) needed to meet a given reliability guarantee. This problem is shown to be coupled by two NP-hard objectives. We characterize the structure of the optimal assignment and develop bi-criteria approximation algorithms. Moreover, we investigate the scaling of the recovery capacity as the network size becomes large. It is shown that the recovery capacity is negligible as compared to the total traffic demands in a large-scale network.