tailieunhanh - Femtocell selection scheme for reducing unnecessary handover and enhancing downlink QoS in cognitive femtocell networks

In the paper, we propose a femtocell selection scheme for femtocell-tofemtocell handover, named Mobility Prediction and Capacity Estimation based scheme (MPCE-based scheme), which has the advantages of the mobility prediction and femtocell’s available capacity estimation methods. Performance results obtained by computer simulation show that the proposed MPCE-based scheme can reduce unnecessary femtocell-tofemtocell handovers, maintain low data delay and improve the throughput of femtocell users. | Research and Development on Information and Communication Technology Femtocell Selection Scheme for Reducing Unnecessary Handover and Enhancing DownLink QoS in Cognitive Femtocell Networks Nhu-Dong Hoang1 , Nam-Hoang Nguyen2 , Trong-Minh Hoang3 and Takahiko Saba4 Viettel R&D Institute, Hanoi, Vietnam 2 University of Engineering and Technology, Vietnam National University Hanoi, Vietnam 3 Post and Telecommunications Institute of Technology, Hanoi, Vietnam 4 Chiba Institute of Technology, Chiba, Japan 1 E-mail: donghoang93@, hoangnn@, hoangtrongminh@, saba@ Correspondence: Nam-Hoang Nguyen Communication: received 24 July 2017, revised 7 August 2017, accepted 30 August 2017 handovers during its connection lifetime because femtocells have small coverage radius and high density [5, 6]. Femtocell selection is an important function of femtocellto-femtocell handover which has to find an accurate target femtocell. An efficient femtocell selection scheme should be able to reduce the number of unnecessary handovers and avoid overloading femtocells. We can find a number of femtocell selection methods in literature such as [7–10] which commonly use mobility prediction or signal strength for selecting a target femtocell. However, to our best knowledge, the problems of unnecessary handovers and FU’s QoS support are still open challenging research issues. Abstract: Femtocell networks have been proposed for indoor communications as the extension of cellular networks for enhancing coverage performance. Because femtocells have small coverage radius, typically from 15 to 30 meters, a femtocell user (FU) walking at low speed can still make several femtocell-to-femtocell handovers during its connection. When performing a femtocell-to-femtocell handover, femtocell selection used to select the target handover femtocell has to be able not only to reduce unnecessary handovers and but also to support FU’s quality of service (QoS). In the .