Traffic behavior simulation of a DECT technology network A. Dimitriou, T. Vasiliadis, G. Sergiadis Aristotle University of Thessaloniki, School of Engineering, Dept. of Electrical & Computer Engineering, Telecommunications Division, 540 06 Thessaloniki, Greece Tel. +30 31 996314, e-mail: sergiadi@eng.auth.gr ABSTRACT In this paper we present the results of a simulation we performed in order to examine DECT’s behavior as far as its traffic capabilities are concerned. Therefore, we consider a network that uses the DECT radio access technology and try to simulate a realistic traffic scenario. We are trying to involve DECT’s characteristics as those were defined by the DECT ETSI specification. The results show a satisfactory capacity behavior for indoor applications. I. INTRODUCTION Towards the final implementation of 3 rd generation telecommunication systems and the early planning of the 4 th generation systems, DECT, a 2 nd generation technology, seems to reflect certain characteristics that should be considered for indoor applications. Considered by many industry and wireless market specialists as a 2,5G system, DECT has been strongly involved in the process of 3G systems standardization. Therefore it poses as the ideal candidate for gaining insight into next generation’s challenges [1]. It uses a radio access technology especially designed for indoor applications. Through the use of Dynamic Channel Allocation scheme, it allows a dynamic adaptation to many different harsh radio environments and assures the use of the best channel available [2-4]. Its Multi Carrier/TDMA/TDD structure permits the avoidance of frequency planning [5]. All base stations use the same channels. It allows an easy network installation, since it adapts to the unexpected needs of the various indoor environments. In this paper we are especially concerned about the behavior of a network that uses the DECT radio access technology in matters of capacity and traffic. Before we moved on to the realization of this simulation we had performed several measurements in a “rough” indoor environment. The results kept us from our original ideas of performing a simple “probability”-based simulation. We were particularly interested in simulating in the best possible way the handover mechanism. In order, however, to do that, we found out that it would be necessary not only to simulate the fast fading indoor environment, but also the randomness of the people’s movement. We believe that the result of this effort has been a realistic approach to simulate the traffic behavior of a network; it produces reliable results and can easily be generalized to simulate the traffic behavior of other systems. II. SIMULATION SCENARIO We consider a square building, where 4 DECT base stations are positioned on the four acmes of another square inside the building, as shown in Figure 1 (the numbers represent the points where the base stations are positioned). Figure 1. Schematic representation of the simulation scenario. Any subscriber can appear in any one of the nine regions that exist in the building (Figure 1). Depending on the region where one appears, one can move towards any direction within the boundaries that are defined by the arrows in Figure 1. Those boundaries are placed in order to keep the subscribers moving towards the inner part of the building, thus provoking more handovers and a more complex traffic situation. 20% of the subscribers are standing still and 80% of them are moving maintaining the same velocity throughout their call. If anyone reaches the boundaries of the building he returns towards the opposite direction.