earticle

영어

IEEE 802.16-series are expected to provide broadband wireless access for a variety of multimedia services. The WiMAX Forum has defined a two-tiered mobility management to minimize handover delay and packet loss. The standards only define the Access Service Network Gateway ASN GW relocation procedures without specifying when the ASN GW relocation should be performed. So to address it previously Gateway Relocation Admission Control (GRAC) was developed, which combines ASN GW relocation and Admission Control (AC) algorithm to maximize system capacity. GRAC incorporates traditional Admission Control (AC) and Wiener Process (WP)-based prediction algorithms to determine when to carry out ASN GW relocation. Unfortunately, it is suitable only for Inter-ASN communications because of the inability to support vertical hand off communications (heterogeneous networks). The decision for vertical handover depends on many factors (cost, load, network bandwidth, coverage, security speed, power consumption etc.) that need to be considered together with the signal strength in the complex heterogeneous wireless environment. Therefore, we propose to use a vertical handover decision algorithm based on the user’s speed and session’s priority (non-real-time or real-time service) of the mobile nodes. Delivers had better channel utilization and preserves QoS requirements of the mobile subscribers and a practical implementation validates our claim.