International Journal of Wireless & Mobile Networks (IJWMN) Vol. 4, No. 6, December 2012 DOI : 10.5121/ijwmn.2012.4605 61           Saied M. Abd El-atty 1 and Z. M. Gharsseldien 2 1 Department of Computer Science and Information, Arts and Science College, Salman Bin Abdulaziz University, 54-11991,Wadi Adwassir, Kingdom of Saudi Arabia s.soliman@sau.edu.sa 2 Department of Mathematics, Arts and Science College, Salman Bin Abdulaziz University, 54-11991,Wadi Adwassir, Kingdom of Saudi Arabia z.gharsseldien@sau.edu.sa ABSTRACT In this paper we investigate the performance of mobile user connectivity in femtocell/macrocell networks. The femto user equipment (FUE) can connect to femto access point (FAP) with low communication range rather than higher communication range to macro base station (MBS). Furthermore, in such emerging networks, the spatial reuse of resources is permissible and the transmission range can be decreased, then the probability of connectivity is high. Thereby in this study, we propose a tractable analytical model for the connectivity probability based on communication range and the mobility of mobile users in femtocell/macrocell networks. Further, we study the interplays between outage probability and spectral efficiency in such networks. Numerical results demonstrate the effectiveness of computing the connectivity probability in femtocell/macrocell networks. KEYWORDS Femtocell, Macrocell, Connectivity, Mobility, Communication range. 1. INTRODUCTION Integration of femtocell technology with the existing macrocell mobile networks is a promising solution not only to improve indoor coverage but also to increase capacity of cellular mobile networks. Therefore, the deployment of femtocells technology will be useful for both users and mobile network operators, since femtocell networks introduce better quality wireless services and data transmission. Furthermore, the users make use of femtocell networks to receive strong signals, and high capacity, as well as low transmission range and power wasting [1]. As a result, the mobile network operators will have the solutions for radio resources limitations, reduction macrocell traffic load and infrastructure cost by saving lots of money by offloading most of the capital expenditure (CAPEX) and operational expenditure (OPEX) onto users [2]. In femtocell networks, the smaller size of femtocell not only provides high spectrum efficiency by using spatial reuse of resources but also decreases the transmission range and then provides high probability of connectivity. The permanent address of the authors is 1 The Dept. of Electronics and Electrical Communications, Faculty of Electronic Engineering, Menoufia University, 32952, Menouf, Egypt. 2 The Dept. of Math., Fac. Sci., Al-Azhar Uni., Nasr City,11884, Cairo, Egypt