Empirical Data from Mobile and IP Telephony

Over the recent years enormous changes in the telecommunication services, techniques, regulations and markets have taken place. However, even with many new exciting services the telephony service is still popular. This paper provides empirical traffic data and observations of telephony traffic patterns in mobile and IP telephony. They are presented and compared with old telephony patterns from Public Switched Telephone Networks (PSTN). The question is whether the characterization of telephony traffic should be reconsidered because new technology and markets might have changed the service and usage. How is the telephony usage patterns influenced by technology changes from fixed to mobile phones, changes in quality from fixed-line phone to mobile and IP telephone, changes in tariffs from usage based to flat-rate subscriptions, and appearance of alternative message based communication means? This paper presents a comparison between recent mobile and IP telephony measurements and telephony measurement obtained nearly four decades ago. The traffic patterns are compared and significant changes in the daily and weekly traffic profiles are observed. In particular, the profile of international calls has significantly changed and does not resemblance any of the standard traffic profiles from ITU E.523. The busy hour call holding times are fitted a log-Normal distribution for domestic and Hyper-Exponential for international calls. Furthermore, the average call holding times show significant variations over the day in flat-rate subscriptions. Finally, the results indicate that the Short Message Service (SMS) seems to serve as a supplement to phone calls, in particular in the evenings, which might change call holding time distribution and traffic intensities.