Performance Evaluation for Mobile WiMAX Handover with a Continuous Scanning Algorithm

With the IEEE 802.16e standard for mobile WiMAX the course for new 4G mobile radio communication systems is set. It offers significantly higher data rates than GSM or WCDMA/UMTS and supports different handover mechanisms and QoS features in contrast to WiFi (IEEE 802.11 g) on the OSI-layer 2 (L2). Since WiMAX-devices are hardly available today and protocol optimizations are strongly restricted with commercially available devices, a simulation model is not far to seek. Thus, we developed and implemented a simulation in OMNeT++ based on the INET framework in order to investigate and evaluate the performance of the new Mobile WiMAX protocol. In this paper we particularly focus on the handover performance on OSI-Layer 2 (L2) for noise affected channels. Beyond the standardized handover we propose a sliding window mechanism for the channel measurements the handover decision is based on. Ultimately a performance evaluation demonstrates the reduction of handover delay for certain noise levels by introducing a continuous scanning process.