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> Introduction
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Why learn about
› Understand the protocols andprocedures involved within the
Evolved Packet System
(EPS).
› Understand how signaling is
performed between the UE,
eNodeB, MME, Serving-
Gateway and Packet Data
Network Gateway.
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Course Objectives
After the completion of this course you will be able to:
› Explain the RRC Protocol
› Explain the PDCP Protocol
› Explain the RLC and MAC Protocols
› Explain the X2/S1 Interface and the X2AP/S1AP Protocol
› Describe attach procedure and UE states and the difference
between connected and idle mode› Describe call setup
› Describe mobility over X2 and S1 Interfaces
› Describe IRAT Mobility
› Describe CS Fallback
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Module Scope and Objectives
› Describe the Evolved Packet System Architecture.
› List the Control and user plane protocols
› Explain the General Protocol model and Protocol
interactions
› Describe the various traffic cases in EPS
Objectives
Scope
› Evolved Packet System Architecture
› Control and user plane protocols
› General Protocol model and Protocol interactions
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> LTE Protocols and Procedures
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3GPP LTE and SAE & Work Items
LTEEUTRAN Specifications
(36 series)
TSG RAN
Specification Group Work ItemResult
SAEEPC Specifications
(From Rel 8 onwards)
TSG SA
Specification Group Work ItemResult
LTE: Long Term Evolution
EUTRAN: Evolved UMTS Terrestrial Radio Access Network
SAE: System Architecture Evolution
EPC: Evolved Packet Core
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Evolved Packet System Architecture
eNB
eNB
eNB
S1
X2
X2
X2
SAE
(System Architecture
Evolution)
LTE
(Long Term Evolution)
EPC
(Evolved
Packet Core)
E-UTRAN
EPS
(Evolved Packet System)
UE
Uu
MME MME
HSS
P/S-GW P/S-GW
S6a
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EPS Protocol Categories
L3 Signalling L2 Transport
• Non Access Stratum (NAS)
Communication between UE and MME
• Radio Resource Control (RRC)
Communication between UE and eNodeB
• Packet Data Convergence Protocol (PDCP)
- Ciphering and integrity protection for RRC messages
- IP header compression/decompression for user plane
•
Radio Link Control (RLC)- Transfer of RRC messages and user data using:
* Acknowledged Mode (AM)
* Transparent Mode (TM) or
* Unacknowledged Mode (UM)
- Error Correction (ARQ)
• Medium Access Control (MAC)
- Error Correction (HARQ)
- Transfer of RRC messages and user data using:- Priority handling (scheduling)
- Transport Format selection• GPRS Tunneling Protocol Control (GTP-C)
- Communication between MME and SGW
- Communication between SGW and PGW
- Communication between MME and MME
• S1 Application Protocol (S1AP)
Communication between eNodeB and MME
• X2 Application Protocol (X2AP)
Communication between eNodeB and eNodeB
• GPRS Tunneling Protocol User (GTP-U)Transfers data between GPRS tunneling endpoints
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General Protocol Model
›
For each layer the payload is called SDU (Service Data Unit)› For each layer SDU+Protocol Header is called PDU (Packet Data Unit)
› Layer n PDU = Layer n+1 SDU
› E.g. A PDCP PDU = RLC SDU and RLC PDU = RLC Header+RLC SDU
PayloadHeader
Layer n SDU
Layer n PDU
Layer n
Layer
n+1
Layer n+1 SDU
Payload
Layer n+1 PDU
Header
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EPS Bearer Service (S1-UP)
EPS Bearer service & Signaling Connection
UE
RBS MME S/P-GW
Data RadioBearer
Signalling
Radio Bearer
NAS Signalling Connection
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UE Protocol Stack
Header
Compression
TM AM
UM
Physical Layer
L2
PDCP
RLC
MAC
RRC
NAS
Integrity/
Ciphering
System Info
Aquisition
Cell
Selection
Paging
Reception
Mobility
Management
Session
Management
Connected
Mode
Mobility
NAS
Security
IP
Application
AS SecurityRRC
Connection
RB
Managementv
Measurement
Reporting
C o n t r o l / R e p o r t S A P s
RA ControlHARQ
ControlRA Control
HARQ
Control
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Segmentation, ARQ
Ciphering
Header Compr.
Hybrid ARQHybrid ARQ
MAC multiplexing
Antenna and
resrouce mapping
Coding + RM
Data modulation
Antenna and
resource mapping
Coding
Modulation
Antenna and
resource
assignment
Modulation
scheme
M A C
s c h e d u
l e r
Retransmission
control
Priority handling,
payload selection
Payload selection
RLC#i
PHY
PDCP#i
User #i User # j
MAC
Concatenation, ARQ
Deciphering
Header Compr.
Hybrid ARQHybrid ARQ
MAC demultiplexing
Antenna andresrouce mapping
Coding + RM
Data modulation
Antenna and
resource demapping
Decoding
Demodulation
RLC
PHY
PDCP
MAC
eNodeB UE
R e d u n d a n c y
v e r s i o n
IP packet IP packet
EPS bearers
E-UTRAN Radio
Bearers
Logical Channels
Transport
Channels
Physical Channels
Protocol Interaction
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UE – MME Control Plane
L1
IP
SCTP
S1-MME
MME
S1-AP
NAS
SCTP
L2
L1
IP
eNodeB
S1- AP
MAC
RLC
PDCP RRC
Relay
MAC
L1
RLC
PDCP
UE
RRC
NAS
L2
Uu
L1
UE P k D NW
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UE–
Packet Data NW
Gateway User Plane
Serving GW PDN GW
S5/S8
UDP/IP UDP/IP
L2 L2
L1 L1
UDP/IP
L2
L1
GTP-U
IP
SGi S1 - U Uu
eNodeB
RLC
L2
PDCP
MAC
L1 L1
PDCP
RLC
MAC
L1
IP
Application
UE
UDP/IP
GTP-U
Relay
GTP-U
Relay
GTP-U
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> Summary
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Summary
UE control planeprotocols
RLC
MAC
PDCP
L1
IP
Application
UE user plane
protocols
PDCP
RLC
MAC
L1
RRC
NASThe control signaling between the UE
and the Evolved Packet Core is done
with NAS protocol.
The control signaling between the UE
and the E-UTRAN (eNodeB) is done
with the RRC protocol.
LTE
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More Information
›
3GPP Technical Specifications 36-series – 3GPP TS 36.331 E-UTRA; RRC Protocol specification
– 3GPP TS 36.323 E-UTRA; Packet Data Convergence Protocol
(PDCP) specification
– 3GPP TS 36.322 E-UTRA; Radio Link Control (RLC) protocol
specification
– 3GPP TS 36.321 E-UTRA; Medium Access Control (MAC) protocol
specification
– 3GPP TS 36.300 E-UTRA; Overall description
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