LTE - Fundamentals

Legacies

1G -> AMPS
Had only voice services.

2G -> GSM/CDMA
Had both voice and data services
GSM -> used Time Division multiplexing
CDMA -> used Code Division multiplexing

3G -> WCDMA/TDSCDMA/EVOD
Higher data rates

4G -> LTE

5G -> NR

Control Plane Protocols ->

User Plane Protocols ->

RRC SIB's

High Level View of PDCP

High Level View of RLC

High Level View of MAC

QOS in LTE

Data Flow in UE

Data Flow in eNodeB

Radio Resource Protocol(RRC) is used to configure and control the radio resource between UE and eNB

Signaling Radio Bearers(SRBs) are used for the transmission of RRC and NAS Message between eNodeB and UEs