WHAT IS THE BEARER CONCEPT SUPPORTED BY THE EPS?

The concept of Evolved Packet System (EPS) bearer in LTE exists for supporting end user data services. EPS bearer is defined between UE and Packet Data Network Gateway (P-GW) in the Evolved Packet Core (EPC).

E-UTRA Radio Bearer and E-UTRAN Access Bearer

From the diagram above , you can see EPS bearer is further sub-divided into an E-UTRA Radio bearer (between the eNodeB and UE over the radio interface) and E-UTRAN Access Bearer ( between eNodeB and SGW over the S1 – interface ) .

Multiplexed Services

When it comes to providing multiplexed services on different EPS bearers. There is many to one mapping between End to End services and EPS Bearers.

Mapping

There is one to one mapping between EPS Bearer , E-UTRAN Access Bearers and E-UTRAN Radio bearer.

GTP Tunnel

Each E-UTRAN Access Bearer is associated with a GTP tunnel over S1 interface.

RLC instance

Each E-UTRAN Radio bearer over the radio air interface is associated with RLC instance. Radio bearers represent different priority queues over the radio interface.