Chance-Constrained Optimization of Reliable Fixed Broadband Wireless Networks

Abstract

In this paper, we extend our former investigation on conceiving reliable fixed point-topoint wireless networks under outage probability constraints [CCKN11b; CCKN11a]. We consider the problem of determining the minimum cost bandwidth assignment of a network, while guaranteeing a reliability level of the solution. If the optimal bandwidth assignment and routing of traffic demands are accomplished, the reliability criterion requires that network flows remain feasible with high probability, regarding that the performance of microwave links is prone to variations due to external factors, e.g., weather. We introduce a chance-constrained programming approach to tackle this problem and we present reformulations to standard Integer Linear Programming (ILP) models, including a budget constrained formulation. To improve the solving performance, we propose new valid inequalities and a primal heuristic. Computational results present a performance analysis of the valid inequalities and the heuristic. Further, the outperformance of the novel model compared to more traditional approaches is documented.

Dimensioning microwave wireless networks

“…Recently, the problem of determining the minimum cost bandwidth assignment of a network while guaranteeing a reliability level of the solution was studied in [9], [14], [15]. The authors propose a chance-constrained programming approach in which, if the optimal bandwidth assignment and routing of traffic demands are met, the reliability criterion guarantees that network flows remain feasible with high probability.…”

“…In [9], the authors proposed as well an alternative budget constrained formulation for which they present a reliability analysis based on different budgets. Instead of minimizing bandwidth costs, their model aims to maximize the reliability of the network while some budget B is not exceeded.…”

“…Note however that, in the new proposed model, the definition of the probability distribution associated with the pairs in BM is slightly different. Instead of using the cumulative probability distribution as in [9], we use a set of modulation distributions:…”

Computing and maximizing the exact reliability of wireless backhaul networks

“…In particular, in case of bad weather, adaptive modulation technology (i.e., the ability to change modulation on the fly) enables preserving functionality of a network link by reducing its capacity. This characteristic makes it very difficult to compute the exact reliability of a network [7] and several methods to approximate this value have recently been proposed [1,2,5].…”

“…We consider a model as in [1,2,5] in which the available capacity on each link is a random variable given by a discrete probability distribution, which depends on the chosen modulation and the possible weather conditions of the link. The available capacities on the links are assumed to be independent of each other.…”