Seamless vertical handover schemes based on pre-registration and pre-authentication in heterogeneous wireless networks

Abstract

The network architecture for next-generation communications is expected to be an integrated heterogeneous environment in order to enable a user to access a particular network depending on application needs and types of radio access networks available. In addition, next-generation network provides an ad hoc network environment using the revolutionary paradigm of a peer-to-peer communication, which allows direct communication between mobile nodes without the use of base station. In this heterogeneous network environments, it is very important for users to provide seamless service while satisfying quality-of-service (QoS) even though they are connected with any access point. Therefore, this dissertation deals with seamless vertical handover schemes and a reliable neighbor discovery scheme for seamless and fast handover in the heterogeneous network environments. First, we propose a seamless vertical handover scheme using interworking between two heterogeneous networks. We present a practical UMTS-WLAN interworking architecture based on 3GPP standards and propose a seamless vertical handover method that guarantees low delay and low packet loss during UMTS-WLAN handover. For low handover delay, the proposed handover scheme performs pre-registration and pre-authentication processes before layer 2 handover. Moreover, it uses packet buffering and forwarding functions in order to reduce packet loss during the handover period. On the above basis, detailed signaling procedures are presented, together with system requirements when a mobile terminal moves from UMTS to WLAN and vice-versa. Numerical and simulation results show that the proposed scheme performs well with respect to signaling cost, handover delay, and packet loss compared with conventional schemes. Second, we propose a new vertical handover scheme using relay concept, in which an ad hoc node takes over and assists some parts of the vertical handover procedures for the fast handover of mobile nodes in he...