3G provides higher bandwidth enabling new applications like video streaming and calling. Key 3G standards include WCDMA, CDMA2000, and TD-SCDMA. These standards evolved from 2G technologies like GSM and CDMA to support higher data rates up to several megabits per second. The transition involved technologies like GPRS, EDGE, EV-DO, and HSPA that served as intermediates between 2G and full 3G.