A Pre-authentication Scheme on WiMAX for QoS Improvement of Mobile Services

IEEE 802.16j mobile relay station (MRS) is used to extend the coverage area of WiMAX. The MRS provides a fixed access link to mobile terminals riding on a vehicle. When a mobile station (MS) moving together with MRS changes its associated base station (BS), it performs network layer handover while MRS performs link layer handover. It usually causes a long service disruption time (SDT) that seriously affects the real-time mobile services such as VoIP. In this article, we proposed a pre-authentication scheme that reduces the disruption time of link layer handover by performing the authentication procedures before the MS roams to another BS. Through both analysis and simulation, we show that with Fast Mobile IPv6, our proposed scheme is able to reduce the SDT significantly in both predictive mode and reactive mode. Therefore it is able to improve the quality of service (QoS) for real-time mobile services.