Evaluation of Mobile WiMAX handover procedure

This paper presents the impact of handover parameters value and an error-prone radio channel over the IEEE 802.16e CDMA-based handover procedure performance. We analytically analyzed the handover latency and connection dropping probability. The results were compared with the experimental measurements conducted on a protocol prototype specially developed for this purpose by using Specification and Description Language. The following parameters were investigated: value of the contention window minimal and maximal size, number of transmission allocations per frame, number of available CDMA ranging codes, timers and maximum retransmission limits used in the processes of ranging, basic capabilities negotiation and registration. We have found that all these parameters need to be carefully adjusted in accordance to the number of stations performing handover at a same time, WiMAX physical layer working parameters, and frame-error rate in the uplink and downlink radio channel.