A green handover protocol in two-tier OFDMA macrocell-femtocell networks

Femtocells are a promising technology to improve network performance with the short-range, low-power, and cost-beneficial small base stations. A femtocell is a low-power wireless access point that operates in licensed spectrum to connect a standard device to an operator's network using a digital subscriber line (DSL) connection. Most of the energy consumption of the telecommunication networks is caused by the base stations. It is important to reduce the energy consumption of the base stations for green ICT (information and communication technology). A two-tier orthogonal frequency-division multiple access (OFDMA) macro-femtocell network is a key issue to significantly reduce the total power consumption of the base stations. In this paper, we develop a green handover protocol in two-tier OFDMA macrocell-femtocell networks. The green handover protocol allows the femtocell base station to completely switch off its radio communication and associated processing when not involved in an active call. To improve the energy efficiency of femtocell base station, the proposed green handover protocol intelligently switches on its radio communication and associated processing, or called a "wake up" from the idle mode, if the remaining data of a mobile host can be completely uploaded through the wake-up femtocell base station. Finally, the mathematical analysis and the performance simulation illustrate that the proposed protocol provides a more power-saving result compared with existing energy-saving handover protocols. (C) 2012 Elsevier Ltd. All rights reserved.