Abstract: The number of mobile users and the demand for better communication is increasing day by day. So to meet up customers demand lots of advancement is being done in the field of communication. Latest communication technology LTE pays large emphasis on providing users with faster data rates and better communication quality. LTE has specified two UE states i.e. Idle mode and connected mode to avoid unnecessary signalling. When the UE does not have any data to send it is said to be in idle mode, and when the data is being send or communication is taking place then the UE is said to be in connected state. Idle mode is important as it saves battery life and also reduces unnecessary signalling. This paper gives a brief overview of both these UE states.

Keywords: Long Term Evolution (LTE), User Equipment (UE), Radio Resource Control (RRC), Radio Resource Control idle state (RRC_IDLE), Radio Resource Control connected state (RRC_CONNECTED)