Fuzzy clustering based Group Vertical Handover decision for heterogeneous wireless networks

In overlay heterogeneous wireless networks, many mobile terminals may operate vertical handover simultaneously which is defined as Group Vertical Handover (GVHO). Conventionally, handover decision schemes designed for a single user may cause network congestion and increasing handover blocking probability in GVHO scenario. To provide seamless handover with QoS guarantee, a fuzzy clustering method (FCM) is proposed by combining the concurrent traffic attributes of GVHO users and the status of available candidate networks. After the combination, users are able to select the proper network based on the dynamic diagram, which is generated by FCM. The collision probability can also be decreased through allocating handover request properly in a specific time window. Compared to the other two schemes, the simulation results show that the proposed scheme reduces the handover blocking probability about 17% and 25% (the maximum rate) respectively.