Investigation of the UMTS to GSM handover procedure

UMTS is a third generation (3G) mobile communications system, currently being standardized and developed by many mobile technology manufacturers and operators. Unlike the second generation systems such as GSM, which provide voice and low speed data services, 3G promises to provide high speed data as well as multiple-data rate services, which is opening doors to many exciting multimedia applications. The initial deployment of UMTS is expected to be in cities, providing islands of coverage. Therefore, effective handover from UMTS to GSM is imperative for mobiles when they roam out of UMTS coverage. The paper presents the results of system simulations which provide some insights into the conditions and parameters involved in inter-system handover from UMTS-FDD to GSM.