Abstract
Seamless and reliable switching across different technologies is the basic requirement of heterogeneous wireless
networks. In order to be always best connected for various applications, the network selection procedure in heterogeneous
environment during vertical handover decision is intended to choose the most suitable network for mobile user. In this paper fuzzy
rule based handover decision scheme is proposed that will help to choose the correct network among WLAN, WWAN and
Cellular network and also finds the necessity of handoff. Fuzzy logic concept is applied to find necessity of handoff and for
handoff decision by considering all the possible network parameters such as RSS, bandwidth, user preference, MS-velocity, MSAP
distance, delay, cost, security and no. of users. To calculate the handoff factor four fuzzy logic controllers are designed in
parallel fashion which reduces the number of rule and system complexity. In this work only 27 rules are used instead of 39
rules
that are needed for 9 attributes to find the value of final vertical handoff factor (VHO) for all the three networks i.e. WLAN,
WWAN and cellular network. Also less number of unnecessary handoffs is resulted for the proposed scheme.