@conference {2997, title = {Interference Management in LTE Femtocell Systems Using an Adaptive Frequency Reuse Scheme}, booktitle = {Wireless Telecommunications Symposium (WTS 2012), London, UK}, year = {2012}, month = {18-20 April}, abstract = {Long Term Evolution (LTE) has developed a new technology in order to enhance indoor coverage. This new technology is called femtocells and is achieved with the use of access points installed by home users. However, interference problem between the femtocell and the macrocell decreases the system{\textquoteright}s capacity and as a result users{\textquoteright} throughput. In this paper we study the interference mitigation techniques in femtocell/macrocell networks and we propose a frequency reuse mechanism that leads to increased overall system performance. In particular, the mechanism aims to maximize throughput via a variety of combinations between inner cell radius and frequency allocation to the macrocell. Additionally, a position minded frequency allocation to the femtocells targets to further optimize the total throughput of the cell.}, keywords = {Femtocell, FFR, LTE}, author = {Christos Bouras and Andreas Papazois and Vasileios Kokkinos and Georgios Kavourgias} } @conference {3012, title = {Power Management over Co-channel Femtocells in LTE-A Systems}, booktitle = {IFIP Wireless Days 2012, Dublin, Ireland}, year = {2012}, month = {21-23 November}, abstract = {The use of femtocells has been an attractive solution since it achieves better coverage and capacity and low cost for deployment and maintenance. However, their performance can be compromised by the cross-tier interference with existing macrocell infrastructure or between adjacent femtocells, especially in the case of co-channel deployment. One way to address this, is adjusting the transmit power of every femto base station with respect for overall performance. To this direction, we have implemented a framework that simulates femtocell overlays over LTE-Advanced (LTE-A) macrocellular systems. The framework allows power management over user-defined femtocell deployment, deciding their power levels according to three different power schemes. The resulting throughput is presented for every point of the macrocell in a user-friendly GUI. In this paper, we present the design of this framework and discuss the results.}, keywords = {Femtocell, Power Control}, author = {Christos Bouras and Andreas Papazois and Vasileios Kokkinos and Georgios Diles} } @conference {3007, title = {A Simulation Framework for LTE-A Systems with Femtocell Overlays}, booktitle = {ACM PM2HW2N 2012 Workshop, Paphos, Cyprus}, year = {2012}, month = {21 - 25 October}, pages = {85 - 90}, abstract = {The use of femtocells is an efficient way to improve cover- age and quality of service while on the other side the deployment cost for the service provider is kept in extremely low level. Long Term Evolution Advanced (LTE-A) systems with femtocell overlays aim to provide better indoor voice and data coverage and to increase network capacity. One of the major technical challenges that femtocell networks are facing nowadays, is the cross-tier interference, i.e., the interference between the femto base stations and the macrocell infrastructure. To this direction, we have designed and implemented a framework that simulates femtocell overlays integrated over LTE-A macrocellular systems. This framework focuses on the impact of cross-tier interference and furthermore is able to estimate the throughput at every point of integrated femtocell/macrocell LTE-A networks. In this paper, we present the design and implementation of this simulation framework and we provide significant experimental results obtained with the aid of this system.}, keywords = {Femtocell, LTE}, author = {Christos Bouras and Andreas Papazois and Vasileios Kokkinos and Konstantinos Kontodimas} } @conference {2991, title = {Interference Behavior of Integrated Femto and Macrocell Environments}, booktitle = {IFIP Wireless Days 2011, Niagara Falls, Ontario, Canada}, year = {2011}, month = {October 10 \&$\#$8211; 12}, abstract = {Abstract{\textemdash}Femtocells are data access points installed by the subscribers to provide better indoor voice and data coverage and to increase system capacity. The integrated femtocell/macrocell networks offer an efficient way to increase access capacity by improving coverage and quality of service while on the other side the deployment cost for the service provider is kept in extremely low levels. One of the major technical challenges that femtocell networks are facing is their interference behavior when they are placed within macrocells. The study presented in this paper focuses on the impact of integrating femtocells in macrocell networks in terms of adjacent cell interference that the macrocell environment adds to users served by a femto base station and vice versa. To this direction, we have designed and implemented a simulation testbed that estimates the cross-tier interference and the throughput in every point of an integrated femtocell/macrocell Long Term Evolution-Advanced (LTE-A) network.}, keywords = {Femtocell, LTE}, author = {Christos Bouras and Antonios Alexiou and Andreas Papazois and Vasileios Kokkinos and Konstantinos Kontodimas} }