Modeling the access to a wireless network at hot spots

In teletraffic engineering, the effective design of wireless networks providing voice and data services at hot spots is of great practical importance. This paper presents a model of such networks in terms of a BMAP/ PH/N retrial queue. Due to the batch occurrence and high correlation of the traffic, it is decisive to choose the correct Batch Markovian Arrival (BMAP) representation of the empirically observed streams of call requests. The numerical results show that there are great differences in important performance measures due to different structures of the chosen BMAP which have the same fundamental rate and the same coefficient of variation of the inter-arrival times. The paper again provides evidence that 'correlation matters'. Yet, further examples show that the coefficient of correlation is not the single characteristic (besides the fundamental rate and coefficient of variation) of the arrival process that has an influence on the performance of the network.