II. MOTIVATION
3G phones offer better services compared to 2G phones, especially regarding bit rate when downloading or uploading data. Moreover they can support data and voice traffic at the same time allowing video calls, for example. However, use of data services is only slowly becoming more widespread, and many costumers still use their phone mainly for voice and Short Message Service (SMS) and in a small portion for data services. Moreover, many areas still have limited 3G coverage and the phone continuously makes hand-offs from 2G to 3G network and vice versa as the mobile phones moves into and out of 3G coverage. Therefore being connected to a 3G network, especially when no data transmission is needed, has an high cost in terms of energy consumption. In this paper we present the results of the measurements made for the most widely used services, namely SMS, voice and data services. SMS is one of the most remarkable success stories in the world of data communication. Already in January 2007 the number of active users of SMS text messaging exceeded two billion. The first SMS typed on a GSM phone was sent in late 1993. The initial growth was slow, but it had an incredible boost over the years. GSM Association reported that in the first three months 2001 more than 50 billion SMS were sent over the world’s GSM networks. In November 2007 Gartner [7] forecasted 2:3 trillion messages will be sent across major markets worldwide in 2008, a 19:6% increase from 2007.