A New Scheme for Network Selection in Heterogeneous Wireless Network using Fuzzy Logic

Abstract

ABSTRACT Ensuring seamless and reliable switching across different constituent technologies is the basic requirement of heterogeneous wireless networks. IEEE 802.21 standard is recommended for 4G networks for coordinating among different mobile network for better services. Still, there exists a scope of further improving its performance by introducing the fuzzy logic concepts in it. The present work aims in this direction where a fuzzy interface system is designed using four different parameters viz. speed of mobile terminal, available bandwidth, received signal strength and number of users. The simulation result show that the number of vertical handoffs in the proposed technique reduced by 27% as compared to the existing fuzzy approach and by 42% as compared to the classical approach. Keywords Heterogeneous networks, seamless mobility, fuzzy logic, handoff. 1. INTRODUCTION The heterogeneous wireless network is a collection of different wireless technologies like cellular networks, wireless metropolitan area network (WiMax) and wireless local area network (WiFi). Besides traditional handoff (between cells of same technology), a vertical handoff (between cells of different technology) is the primary requirement for the proper functioning of heterogeneous networks. The most desiring features are to maintain best quality of service (QOS) by connecting to most fascinating network among the available networks. Figure 1 shows the integrated network structure of cellular networks, Wi-Fi and WiMax. In WiFi or WiMax the point of attachment through which a user gets connected is called an access point and in cellular network is termed as base station. The three basic steps in the vertical handover process are network discovery, handover decision and handover execution process [1]. In the traditional cellular system also known as GSM, the threshold comparison of different specific parameter metrics is used to make handover decisions [2]. The inter-system handovers are not only supposed to maintain ongoing connections but also to provide users with better services and to meet their individual requirements. In contrast to horizontal handover, vertical handover considers not only the received signal strength (RSS) but also the service class Mapping between handoff-in and handoff-out networks [3].The IEEE 802.21 standard defines the basic requirement for heterogeneous mobility. Quality of service is measured with the performance of transmission of data, network technologies and service accuracy [4]. The idea is to provide good connectivity with different network, reduction in call dropping and good quality of service. A cell phone call may be interrupted or drop after an unnecessary handover or incorrect handover. An unnecessary handover decision can degrade the quality of service and can also interrupt the ongoing communication. So it is essential that the handover process execute seamlessly and accurately to improve the quality of service. The multimedia applications like video streaming, VOIP, web browsing requires good quality of service. Therefore it is mandatory to indicate the quality of a vertical handover network selection and the network performance. In the vertical handover quality can be define as reduction in ping-pong effect, reduction in interruption in the ongoing call during handover and enhancing the throughput of the system [5].The scheme presented in this work shows better performance in this regard.