What is the concept of 4G
1. 4G refers to the fourth-generation mobile communication technology. 2. In the choice of 4G international technical standards, China has adopted LTE, which has two communication modes: TD-LTE and LTE-FDD. 3. LTE is a high-speed wireless communication standard applied to mobile phones and data card terminals. On December 6, 2010, the International Telecommunication Union officially called LTE 4G. 4. The LTE system has two standards: LTE-FDD and TDD-LTE, namely frequency division duplex LTE system and time division duplex LTE system. The main difference between the two technologies lies in the physical layer of the air interface. (1) LTE-FDD system air interface uplink and downlink transmission adopts a pair of symmetrical frequency bands to receive and send data. (2) The uplink and downlink of the TDD-LTE system use the same frequency band to transmit on different time slots. (3) Compared with FDD duplex mode, TDD has a higher spectrum utilization rate.