Functionality of E-UTRAN Logical Entities

Functionality of E-UTRAN

As shown in this post, E-UTRAN can be explained as E-UTRAN logical nodes and E-UTRAN interfaces

E-UTRAN Logical Nodes

1. eNB (evolved NodeB)
2. MME (Mobility Management Entity)
3. S-GW (Serving Gateway)

E-UTRAN Interfaces

1. X2 Interface (Interface between eNB's)

2. S1 Interface

   1. S1-MME Interface (Interface between eNB and MME)

   2. S1-U Interface (Interface between eNB and S-GW)

eNB Functionality

1. Functions for Radio Resource Management: Radio Bearer Control, Radio Admission Control, Connection

2. Mobility Control, Dynamic allocation of resources to UEs in both uplink and downlink (scheduling)

3. IP header compression and encryption of user data stream

4. Selection of an MME at UE attachment when no routing to an MME can be determined from the information

5. provided by the UE

6. Routing of User Plane data towards Serving Gateway

7. Scheduling and transmission of paging messages (originated from the MME)

8. Scheduling and transmission of broadcast information (originated from the MME or O&M)

9. Measurement and measurement reporting configuration for mobility and scheduling

10. Scheduling and transmission of PWS (which includes ETWS and CMAS) messages (originated from the MME)

11. CSG (Closed Subscriber Group) handling

12. Transport level packet marking in the uplink

MME Functionality

1. NAS signalling

2. NAS signalling security

3. AS Security control

4. Inter CN node signalling for mobility between 3GPP access networks

5. Idle mode UE Reachability (including control and execution of paging retransmission)

6. Tracking Area list management (for UE in idle and active mode)

7. PDN GW and Serving GW selection

8. MME selection for handovers with MME change

9. SGSN selection for handovers to 2G or 3G 3GPP access networks

10. Roaming

11. Authentication

12. Bearer management functions including dedicated bearer establishment

13. Support for PWS (which includes ETWS and CMAS) message transmission

14. Optionally performing paging optimization

S-GW Functionality

1. The local Mobility Anchor point for inter-eNB handover

2. Mobility anchoring for inter-3GPP mobility

3. E-UTRAN idle mode downlink packet buffering and initiation of network triggered service request procedure

4. Lawful Interception

5. Packet routing and forwarding

6. Transport level packet marking in the uplink and the downlink

7. Accounting on user and QCI granularity for inter-operator charging

8. UL and DL charging per UE, PDN, and QCI

Functionality and other details of the Interfaces will be explained in next post