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WiMAX and WiFi Heterogeneous Networks 1281
gate the impact of key pre-distribution misses, the proposed scheme stores keys onto a local
trusted key holder from which BSs or APs are tasked to retrieve the required key. By the
approaches of pre-authentication, it will not suffer a longer delay. However, since an AAA
server is normally located far away from the BS/AP, it may incur various accidents to degrade
the system performance such as a connection loss between the BS/AP and the AAA server.
In this paper, we propose a new fast and secure HO authentication scheme based on cre-
dential ticket for WiMAX and WiFi heterogeneous networks. Our proposed scheme achieves
outstanding performance compared to Shidhani et al.’s scheme [21] and Huang et al.’s scheme
[22] in terms of communication and computation cost, while fulfilling essential HO security
requirements such as mutual authentication and protection against Man-in-the-Middle attack.
3 Preliminaries
In this section, the network model, adversary model and flow chart of our proposed scheme
based on different HO situations are presented.
3.1 Network Model
Figure 1 depicts a simplified interworking architecture under discussion, where a WiMAX
network is interconnected with WLANs through the WiFi Interworking Function (WIF)
predefined by the WiMAX forum for roaming support [24]. According to the network model,
we can see that its topology is Point-to-multipoint (PMP). It is noted that the Ad Hoc networks
Fig. 1 The WiMAX-WiFi interworking architecture
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