The Radio Resource Control (RRC) protocol is used in
UMTS
The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the Inte ...
,
LTE and
5G on the
Air interface
The air interface, or access mode, is the communication link between the two stations in mobile or wireless communication. The air interface involves both the physical and data link layers (layer 1 and 2) of the OSI model for a connection.
Physi ...
. It is a layer 3 (Network Layer) protocol used between UE and Base Station. This protocol is specified by
3GPP in TS 25.331 for
UMTS
The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the Inte ...
, in TS 36.331 for
LTE and in TS 38.331
3GPP TS 38.331 NR; Radio Resource Control (RRC); Protocol specification
/ref> for 5G New Radio. RRC messages are transported via the PDCP Packet Data Convergence Protocol (PDCP) is specified by 3GPP in TS 25.323 for UMTS, TS 36.323 for LTE and TS 38.323 for 5G. PDCP is located in the Radio Protocol Stack in the UMTS/LTE/5G air interface on top of the RLC layer.
PDCP provides its ...
-Protocol.
The major functions of the RRC protocol include connection establishment and release functions, broadcast of system information, radio bearer establishment, reconfiguration and release, RRC connection mobility procedures, paging notification and release and outer loop power control.
By means of the signalling functions the RRC configures the user and control planes according to the network status and allows for Radio Resource Management strategies to be implemented.
The operation of the RRC is guided by a state machine which defines certain specific states that a UE may be present in. The different states in this state machine have different amounts of radio resources associated with them and these are the resources that the UE may use when it is present in a given specific state. Since different amounts of resources are available at different states the quality of the service that the user experiences and the energy consumption of the UE are influenced by this state machine.
RRC inactivity timers
The configuration of RRC inactivity timers in a W-CDMA network has considerable impact on the battery life of a phone when a packet data connection is open.
The RRC idle mode (no connection) has the lowest energy consumption. The states in the RRC connected mode, in order of decreasing power consumption, are CELL_DCH (Dedicated Channel), CELL_FACH (Forward Access Channel), CELL_PCH (Cell Paging Channel) and URA_PCH ( URA Paging Channel). The power consumption in the CELL_FACH is roughly 50 percent of that in CELL_DCH, and the PCH states use about 1-2 percent of the power consumption of the CELL_DCH state.
The transitions to lower energy consuming states occur when inactivity timers trigger. The T1 timer controls transition from DCH to FACH, the T2 timer controls transition from FACH to PCH, and the T3 timer controls transition from PCH to idle.
Different operators have different configurations for the inactivity timers, which leads to differences in energy consumption.[L. de Bruynseels, “Tuning Inactivity Timer Settings in UMTS”, white
paper, Commsquare Ltd., 2005] Another factor is that not all operators use the PCH states.
See also
* Radio Resource Management Radio resource management (RRM) is the system level management of co-channel interference, radio resources, and other radio transmission characteristics in wireless communication systems, for example cellular networks, wireless local area networks, ...
* Mobility management
Mobility management is one of the major functions of a GSM or
a UMTS network that allows mobile phones to work. The aim of mobility management is to track where the subscribers are, allowing calls, SMS and other mobile phone services to be deli ...
* Radio Network Controller
The Radio Network Controller (RNC) is a governing element in the UMTS radio access network (UTRAN) and is responsible for controlling the Node Bs that are connected to it. The RNC carries out radio resource management, some of the mobility managem ...
* UMTS
The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the Inte ...
* WCDMA
The Universal Mobile Telecommunications System (UMTS) is a 3G, third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the I ...
References
{{Mobile telecommunications standards
3GPP standards