gao co2 nong du xiao xing tea co2 ji guang qi

Abstract

Around the year 2000, research in mobile communication focused on the transition from second-generation (2G) digital systems such as GSM to early third-generation (3G) technologies. Key research areas included CDMA, handover mechanisms, spectrum efficiency, error control coding, and mobility management. This period laid the foundation for high-speed mobile data services and global cellular connectivity.