Operations Research Letters 33 (2005) 134–142 Operations Research Letters www.elsevier.com/locate/dsw A two-phase greedy algorithm to locate and allocate hubs for xed-wireless broadband access Ramesh Bollapragada a; b , Jerey Camm c , Uday S. Rao c ; ∗ , Junying Wu c a College of Business, San Francisco State University, San Francisco, CA 94132, USA b Bell Laboratories, Lucent Technologies, Holmdel, NJ 07733, USA c QAOM Department, Lindner Hall, College of Business, University of Cincinnati, Cincinnati, OH 45221, USA Received 18 March 2003; received in revised form 1 February 2004; accepted 6 May 2004 Abstract We study a two-phase, budget-constrained, network-planning problem with multiple hub types and demand scenarios. In each phase, we install (or move) capacitated hubs on selected buildings. We allocate hubs to realized demands, under technological constraints. We present a greedy algorithm to maximize expected demand covered and computationally study its performance. c  2004 Elsevier B.V. All rights reserved. Keywords: Telecommunications; Fixed-wireless; Location; Greedy algorithm; Stochastic programming 1. Introduction In the broadband-access business, xed-wireless technology is gaining popularity as a fast, cost- eective alternative to other telecommunication technologies. Worldwide service revenues for xed-wireless access are expected to exceed $41 billion in 5 years, according to the ARC Group (www.arcgroup.com; see the report titled “Broadband access: opportunities in xed-wireless”). Faced with the challenge of designing and expanding wireless networks to balance coverage, capacity, time to mar- ket, and cost, both practitioners and researchers have extensively studied problems in deploying telecom- munication networks. * Corresponding author. E-mail address: uday.rao@uc.edu (U.S. Rao). This paper focuses on a last-mile, xed-wireless network-planning problem with a two-phase planning horizon. At the beginning of each phase, the main decision is to determine the number, type, and loca- tion of hubs (aggregation nodes) to be installed. There are multiple hub types, diering in cost and capac- ity. An installation budget is specied for each phase. In the second phase, some of the hubs installed in the rst phase may be moved at a fraction of the cost of installing new hubs. It may be desirable to move hubs when the geographical distribution of de- mand changes over time, when move costs are low, and when the second-phase budget is limited. We for- mulate the problem as a stochastic program with re- course actions contingent on realized demand: after each phase of hub-installation or move decisions are made, demand for the wireless service materializes at the dierent buildings. The available hubs are then 0167-6377/$ - see front matter c  2004 Elsevier B.V. All rights reserved. doi:10.1016/j.orl.2004.05.007