Dimensioning microwave wireless networks

Abstract

International audienceWe aim at dimensioning fixed broadband microwave wireless networks under unreliable channel conditions. As the transport capacity of microwave links is prone to variations due to, e.g., weather conditions, such a dimensioning requires special attention. It can be formulated as the determination of the minimum cost bandwidth assignment of the links in the network for which traffic requirements can be met with high probability, while taking into account that transport link capacities vary depending on channel conditions. The proposed optimization model represents a major step forward since we consider dynamic routing. Experimental results show that the resulting solutions can save up to 45% of the bandwidth cost compared to the case where a bandwidth over-provisioning policy is uniformly applied to all links in the network planning. Comparisons with previous work also show that we can solve much larger instances in significantly shorter computing times, with a comparable level of reliability

Advanced Optimization Models For Bandwidth Provisioning And Routing In Fixed Microwave Backhaul Networks

“…Similarly to some previous work [13,15], our dataset is formed by a number of instances of real-world network topologies and traffic demands proposed by SNDLIB [16]. We consider 3 bandwidths (7 MHz, 14 MHz ,28 MHz) having 20, 36 and 48 cost unities, respectively, and 6 modulation schemes (PSK, 16QAM, 32QAM, 64QAM, 128QAM and 256QAM).…”

“…The authors in [12] proposed a methodology to compute the exact reliability of a backhaul wireless network and to optimize its design given a limited budget. Finally, Kodjo et al [13] worked on an optimization model to dimension a backhaul microwave network while considering an dynamic routing scheme. Based on a column-generation framework, the initial problem is divided into two sub-problems: a master problem and a pricing problem.…”

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.…”

“…However, the proposed formulation requires using a unique routing, independently of the conditions, and so the usage of network resources is not fully optimized. Later, a mixedinteger linear programming formulation based on column generation has been proposed [5], where the columns are network configurations (a capacity per link) and the routing may change for each configuration. Hence, it provides a better approximation of the reliability of the network compared to previous works.…”