Mobile WiMAX is one of the most promising technologies for broadband wireless communication. The IEEE 802.16e standard for Mobile WiMAX, the enhanced version of the IEEE 802.16 standard with mobility support, defines the implementation of hard handover is mandatory. However, the long interruption of hard handover is horrible for delay and packet loss sensitive real-time applications such as IPTV, VolP, SatTV. To solve this problem without many changes to 802.16e equipments, we propose an enhanced link-layer QoS aware handover scheme- Passport Handover to accelerate handover process. We also propose a connection CID assignment strategy to avoid confliction of CIDs of handing over services with that of ongoing services in the target BS. Simulation results prove that the scheme makes real-time downlink data transmission interruption so brief that users will not perceive the interruption. And it also greatly reduces uplink data transmission delay and packet loss probability.
