1. LTE Signaling Flow

2. Content Interface and protocol Signaling Flow of S1 Interface
Signaling Flow of X2 Interface
Signaling Flow of Basic Service

3. Network architecture and interfaces

4. Functional division of EPC and E-UTRAN

5. Control Plane Protocol

6. User Plane Protocol

7. Signaling and data flow
Signaling flow
Data flow

8. What is bearer ? Non-GBR bearer E-RAB Data Radio Bearer Default Bearer
EPS bearer
Non-GBR bearer
E-RAB
Data Radio Bearer
Default Bearer
EPS bearer: An EPS bearer uniquely identifies traffic flows that receive a common QoS treatment between a UE and a PDN GW
E-RAB: An E-RAB uniquely identifies the concatenation of an S1 Bearer and the corresponding Data Radio Bearer. When an E-RAB exists, there is a one-to-one mapping between this E-RAB and an EPS bearer of the Non Access Stratum.
Data Radio Bearer: the Data Radio bearer transports the packets of an E-RAB between a UE and an eNB. There is an one-to-one mapping between the E-RAB and the Data Radio Bearer.
Default Bearer: The EPS bearer which is first established for a new PDN connection and remains established throughout the lifetime of the PDN connection.
Non-GBR bearer: An EPS bearer that uses network resources that are not related to a guaranteed bit rate (GBR) value.
GBR bearer: related to a guaranteed bit rate (GBR) value.
An EPS bearer uniquely identifies traffic flows that receive a common QoS treatment between a UE and a PDN GW

9. EPS Bearer Service Architecture

10. NAS signaling connection UE-associated logical S1-connection
Concept of Connection
Uu（X1）interface
S1 interface
NAS signaling connection
UE-associated logical S1-connection
Uu（X1）: interface between an UE and E-UTRAN.
S1: interface between an eNB and an EPC, providing an interconnection point between the E-UTRAN and the EPC.
UE-associated logical S1-connection: The UE-associated logical S1-connection uses the identities MME UE S1AP ID and eNB UE S1AP ID according to definition in [23.401]. For a received UE associated S1-AP message the MME identifies the associated UE based on the MME UE S1AP ID IE and the eNB identifies the associated UE based on the eNB UE S1AP ID IE. The UE-associated logical S1-connection may exist before the S1 UE context is setup in eNB.
NAS signaling connection: is a peer to peer S1 mode connection between UE and MME. A NAS signaling connection consists of the concatenation of an RRC connection via the "LTE-Uu" interface and an S1AP connection via the S1 interface.

11. Content Interface and protocol Signaling Flow of S1 Interface
Signaling Flow of X2 Interface
Signaling Flow of Basic Service

12. S1 Setup
The purpose of the S1 Setup procedure is to exchange application level data needed for the eNB and MME to interoperate correctly on the S1 interface. This procedure shall be the first S1AP procedure triggered after the TNL association has become operational. The procedure uses non-UE associated signalling.
This procedure erases any existing application level configuration data in the two nodes and replaces it by the one received. This procedure also re-initialises the E-UTRAN S1AP UE-related contexts (if any) and erases all related signalling connections in the two nodes like a Reset procedure would do, and clears MME overload state information at the eNB. If the eNB initiating the S1 Setup procedure supports a CSG cell, the procedure shall report the CSG ID(s) of the supported CSGs.

13. eNB Configuration Update
The purpose of the eNB Configuration Update procedure is to update application level configuration data needed for the eNB and MME to interoperate correctly on the S1 interface. This procedure does not affect existing UE-related contexts, if any.

14. MME Configuration Update
The purpose of the MME Configuration Update procedure is to update application level configuration data needed for the eNB and MME to interoperate correctly on the S1 interface. This procedure does not affect existing UE-related contexts, if any.

15. Content Interface and protocol Signaling Flow of S1 Interface
Signaling Flow of X2 Interface
Signaling Flow of Basic Service

16. X2 Setup
The purpose of the X2 Setup procedure is to exchange application level configuration data needed for two eNBs to interoperate correctly over the X2 interface. This procedure erases any existing application level configuration data in the two nodes and replaces it by the one received. This procedure also resets the X2 interface like a Reset procedure would do.
The procedure uses non UE-associated signalling

17. eNB Configuration Update
The purpose of the eNB Configuration Update procedure is to update application level configuration data needed for two eNBs to interoperate correctly over the X2 interface.
The procedure uses non UE-associated signalling.

18. Load Indication
The purpose of the Load Indication procedure is to transfer load and interference co-ordination information between eNBs controlling intra-frequency neighboring cells.
The procedure uses non UE-associated signalling

19. Resource Status Request
This procedure is initiated by eNB2 to report the result of measurements requested by eNB1 using the Resource Status Reporting Initiation.
The procedure uses non UE-associated signalling

20. Resource Status Reporting Initiation
This procedure is used by an eNB to request the reporting of load measurements to another eNB.
The procedure uses non UE-associated signalling.

21. Content Interface and protocol Signaling Flow of S1 Interface
Signaling Flow of X2 Interface
Signaling Flow of Basic Service

22. PLMN selection and cell selection

23. System Information Broadcast
3GPP

24. Random access procedure
每个小区64个preamble，而preamble是由ZC序列产生

25. UE Attach
3GPP

26. UE Detach( power off in idle)
3GPP

27. UE Detach( power off in connected)
3GPP

28. UE Detach(no power off in idle)
3GPP

29. UE Detach(no power off in connected)
3GPP

30. Paging(system information changed)
3GPP

31. Paging(MME trigger)
3GPP

32. Service Request(UE trigger)
3GPP

33. TAU in Idle(no active identifier)
3GPP

34. TAU in Idle(setup active identifier)
3GPP

35. TAU in Connected
3GPP

36. E-RAB Setup
3GPP

37. E-RAB Release
3GPP

38. RRC Connection Re-establishment
3GPP

39. UE Handover between one eNB’s cells
3GPP

40. UE Handover between the different eNB’s cells(through X2 interface)
3GPP

41. UE Handover between the different eNB’s cells(through S1 interface)
3GPP