Media Independent Handover-based Competitive On-Line CAC for Seamless Mobile Wireless Networks

Abstract

In Media Independent Handover (MIH), Call Admission Control (CAC) and Vertical Handoff (VH) are two important mechanisms in a Mobile Wireless Networks (MWNs) that consists of various types of wireless networks (e.g., WiMAX and WiFi) and cellular communications (e.g., 3G, 3.5G and 4G). First, an adaptive CAC is needed in base stations for achieving high network reward while guaranteeing QoS requirements. Second, an efficient vertical handoff enables mobile stations accomplishing seamless, fast, QoS-aware mobility in MWNs. In CAC, several studies have proposed the mechanisms: the static resource reservation-based, bandwidth borrow-based and Markov chain model-based approaches. They suffer from moderate performance in Grade of Service (GoS), Fractional Reward Loss (FRL) and transmission quality. In VH, it should consider both the received signal strength (RSS) and the service-class mapping between the serving and target networks. Most studies adopted the integration of a RSS-based method with hysteresis to minimize unnecessary handoffs, but high handoff dropping and low network utilization limit the contributions. This work thus proposes a MIH-based competitive on-line (COL) CAC for vertical handoff in a loosely-coupled MWN. First, in a base station (BS) the COL CAC models the resource occupancy of each wireless network in a MWN as a Markov chain model, and then forms a cost-reward CAC for maximizing network reward. Second, in MS the VH scheme adopts a predictive RSS to predict the moving trend of each mobile station to select the optimal target network. Numerical results indicate that the proposed approach outperforms other approaches in GoS, FRL and the number of vertical handoffs while yielding competitive utilization.