True for 2G, but for 3G and 4G most deployments are using full duplex (FDD) where reception and transmissions can happen concurrently and use different frequenc

True for 2G, but for 3G and 4G most deployments are using full duplex (FDD) where reception and transmissions can happen concurrently and use different frequencies. The only exception for 3G is China with its TD-SCDMA standard. Everywhere else, 3G is FDD. For 4G, there is a TDD variant. It's mostly used in China and on some specific high bands (2.3/2.5 GHz around Wifi, 3.5 GHz). But in western countries when one use 4G it's FDD.