Introduction

Abstract

The universal mobile telecommunications system (umts) is a technical standard for a third generation (3g) telecommunication system. umts provides data rates more than three times higher than its second generation (2g) predecessors.1 The increased speed enables, for example, video calls, music downloads, or fast web surfing. The technology is already widely available. In 2007, a total of 166 commercial umts radio networks are operational in 66 countries covering all continents (umts Forum, 2007), and there are already more than 100 million umts subscribers (3GToday.com, 2007; umts Forum, 2006). The market for mobile telecommunication is, however, increasingly competitive, therefore operators need to invest effectively In Western Europe, mobile phone penetration has reached 100% in 2006 and the average revenue per customer is declining (3G.co.uk, 2007). Besides spectrum license fees, the main cost driver is network infrastructure (Ellinger et al., 2002). Radio network planning can cut operational and capital expenditure by up to 30% (Dehghan, 2005).