What are bearers in LTE?
What are bearers in LTE?
In a mobile network using the Long Term Evolution (LTE) architecture, bearers are the tunnels used to connect the user equipment to Packet Data Networks (PDNs) such as the Internet. In practice, bearers are concatenated tunnels that connect the user equipment to the PDN through the Packet Data Network Gateway (P-GW).
What is default and dedicated bearers in LTE?
The first EPS bearer that is activated when a PDN connection is established in LTE is called the “default bearer”. This bearer remains established during the lifetime of the PDN connection. Additional EPS bearers that may be activated for a PDN connection are called “dedicated bearers”.
How many EPS bearers are used in LTE?
As seen in Figure 1, an EPS bearer actually is a concatenation of the following three bearers (DRB, S1 bearer and S5 bearer): [UE] – [eNB]: Data Radio Bearer (DRB)
What is GBR and non GBR bearer in LTE?
Dedicated bearers can be either GBR (Guaranteed Bit Rate) or non-GBR. A GBR bearer has a guaranteed bit rate and MBR (Maximum Bit Rate) while more than one non-GBR bearer belonging to the same UE shares an AMBR (Aggregate Maximum Bit Rate).
What is S1 bearer in LTE?
An S1 bearer is the connection between the eNodeB and the MME/SGW. An uplink TFT is used to map the UE uplink traffic to specific QoS parameters, with the mapping carried out at both the eNodeB and the UE. Mapping for the downlink TFT is carried out at the SGW or the PGW.
What are different bearer services?
The bearer services include the following: Rate adapted sub-rate information like circuit switched asynchronous and synchronous duplex data, 300-9600 bits. Speech and data swapping during a call, i.e. alternate speech and data. Modem selection, i.e. selection of 3.1 kHz audio service when inter-working with ISDN.
What is EPS bearer?
EPS bearer is a combination of several sub bearers which are E-RAB bearer, Radio bearer, S1 bearer, S5 bearer and S8 bearer: E-RAB bearer: transports the packets of an EPS bearer between UE and SGW. External bearer: transports the user packets between PGW and external networks.
What is IMS bearer?
The two default bearer allow redirecting flows to either the IMS operator APN or Internet APN. In this typical example, the Default bearer 1 is used for signalling messages (SIP signalling) related to the IMS network. It uses QCI 5. The Dedicated bearer is used for VoLTE VoIP traffic.
What is bearer QoS?
‘Bearer’ is basically a virtual concept and is a set of network configuration to provide special treatment to set of traffic. e.g. VoIP packets are prioritized by network compared to web browser traffic. In LTE, QoS is applied on Radio bearer, S1.
What is X2 and S1 interface?
eNodeBs have two interfaces, the X2 interface permits eNodeBs to intercommunicate with each other directly, and the S1 interface permits communication with the “Packet Core”. The X2 is the interconnecting interface between two eNodeBs in LTE network and supports both Control Plane and User Plane.
What is S5 interface?
S5 interface It provides user plane tunnelling and tunnel management between Serving GW and PDN GW. It is used for Serving GW relocation due to UE mobility and if the Serving GW needs to connect to a non-collocated PDN GW for the required PDN connectivity.
What are the two types of bearer services of GSM?
GSM – User Services
- Telephony services or teleservices.
- Data services or bearer services.
- Supplementary services.
What are the bearers of the LTE system?
LTE system provides end to end service using the hierarchy of LTE bearers shown in the figure. An LTE EPS bearer provides user plane connectivity between the UE and PDN gateway. EPS is the short form of Evolved Packet System. An initial EPS bearer is established when the UE registers with the network using ‘attach procedure’.
What is an’eps bearer’in LTE?
During ‘LTE attach’ procedure, the network establishes this EPS Bearer between the UE and the PGW. The PGW assigns an IP address for this Bearer. The UE uses this IP address, in order to communicate with the PDN. In addition, the PGW assigns a QoS for this Bearer, which guarantees the QoS for the data passing in this Bearer.
What is the LTE signalling radio bearer used for?
LTE Signalling radio bearers ( SRB) are used for the transfer of RRC and NAS signalling messages. • RRC messages are used as signalling between UE and eNodeB. • NAS (Non Access Stratum) messages are used as signalling between UE and MME.
When is default bearer established in LTE network?
In an LTE mobile network, one default bearer is established to a default P-GW whenever the user equipment device is activated (this means the user equipment is on and has performed authentication).