Abstract-Typically, scatterers in an environment are not spread and rms delay spread (RDS). We use a geometric distributed uniformly but rather observed to occur in clusters. channel model based on COST259 for an outdoor radio enviIdentification of clusters is an issue under discussion. To this ronment. Note that in the COST259 model, NoC is a random end, we study the effect of number of clusters on channel .. ' model through computer simulations. We focus on a geometric parameter. However, in this paper, fixng a scatterer scenario, stochastic directional channel model based on COST259. Fixing we group the scatterers into varying NoC and compute the a scatterer scenario, we calculate root mean square delay and rms angular and delay spreads of the corresponding channel angular spreads when scatterers are grouped into varying num-model.bers of clusters and study how sensitive these parameters are to the number of clusters used in this channel model. II. STRUCTURE OF THE SYSTEM I. INTRODUCTION We consider a circular cell of radius Rceii where base station For the improvement of existing mobile radio systems, real-(BS) is placed at the center of the cell (origin). Mobile station istic channel models are required. In this work, we concentrate (MS) can be assumed to be located at any point in the cell. on a geometric stochastic channel model based on COST259 We assume a number of scatterers are distributed over the cell [1]. In this model the ray paths are coming from the scatterers area. These scatterers are grouped into clusters. Each scatterer distributed in the cell. Number and the density of scatterers inside the cluster represents a single multi-path component. differ according to the environment. From the experimental The geometrical representation is given in Fig. 1. data, it is observed that scatterers tend to occur in groups [2]. Therefore, the scatterers are grouped into clusters. Handling the channel by clustering of scatterers enables us to get a more simplified approach and physically appealing picture.Clusters of scatterers in a propagation environment are typiFar cluster m cally identified through channel measurements. To estimate the of scatterers location of clusters throughout the cell, one approach is to use BS the angle of arrival data from the measurements. The clusters are then specified according to their contribution to the total R received power [3]. According to measurement results, cluster cell locations and parameters such as propagation delays, angles of arrival and departure for the scatterers within each cluster can be modeled using appropriate probability distribution functions. Afterwards, the impulse response of the geometry based stochastic channel model is evaluated using these parameters [4]. COST259 is one of the geometric channel models and its parameters are based on the number and the location of at tranmoite s.ign alav the bas saion daies clusters, and the existence of visibility regions [5]. Since the athemblsaiowthaprcurdlywihdpns clusters, and .. of..visibility.region se...