LTE (LONG TERM EVOLUTION) ARCHITECTURE
HISTORY
|
- Two Systems that impacted almost every Human Life
- (i) Mobile Communication Via 2G Networks.
- (ii) Wired & Wireless Data Connectivity via xDSL & WLAN 802.11 a/b/g standards.
- 3G Networks is the first major step towards the convergence of both these technologies
THE WAY TO LTE-3G
LIMITATIONS
•
The
‘Maximum Bit Rates’ are still in the range of
20mbps
•
This is way behind the other popular wireless
technologies like
•
WiFi:
802.11 a/b/g/n
•
WiMax:
802.16 e/m
•
The ‘Latency’ of User Plane Traffic (UMTS
> 30ms) and Resource
• Management Procedures (UMTS > 100ms) is
still too high
•
The
‘Terminal Complexity’ of WCDMA systems is quite high, and resulting
(i)
Expensive Equipment
(ii)
Poor Performance
LTE GOALS
•
The
‘Terminal Complexity’ of WCDMA systems is quite high, and resulting
•
It shall
Compete especially with 802.16e/m in data rates
•
It must
retain the high mobility features of GSM/UMTS
LTE
SAE DIAGRAM AND FEATURES
LTE SAE DIAGRAM
LTE FEATURES:
·
Simplify the RAN: Reduced the number of RAN
Nodes and Interfaces.
·
Reduce Latency.
·
Increase Throughput and Improve Spectrum
Efficiency.
·
Flexibility in using Frequency Bands.
·
Migrate to Optimized PS Domain with no CS
Domain.
·
Flat Architecture: Minimize the risk of
single point of failures in the network.
·
Efficient Inter-working between 3G and Non-3G
specified systems.
·
Improve Terminal Power Efficiency.
·
All IP Transport Network.
WIRELESS
TECHNOLOGY COMPARISON
LTE
/SAE INTERFACE ARCHITECTURE
NETWORK
ELEMENT FUNCTIONS
eNODE B Functons:
·
Only Network Element in EUTRAN.
·
eNB Can Handle Several Cells.
·
Radio Admission Control & Radio Resource
Management(RRM) Dynamic Resource Allocation(Scheduler).
·
Radio Bearer Mgmt: Setup, Modification and
Release.
·
UE Connection State Management and UE-MME
Connection MME Selection at the Attach of the UE.
·
Measurements Collection and Evaluation.
·
Handover Decisions and Triggering. eNB-eNB
Connections to Handle HO Ciphering and Integrity Protection.
·
IP Header Compression and Decompression User
Data Routing between UE and SAE-GW System Information Broadcasting.
·
Transmission of Paging Messages to UEs.
MME Functons:
·
Pure Signalling Entity in EPC. Contains VLR
Functionality with-in!
·
Subscriber Attach/Detach: Non-Access Signalling
(NAS).
·
Idle State Mobility Handling: Tracking Area
Updates.
·
MME-MME Connections to Handle Handovers &
TAUs.
·
Signalling Co-Ordination For SAE Bearer Setup
& Modification & Release.
·
Security (Authentication, Ciphering,
Integrity Protection.
·
Trigger and Distribution of Paging Messages
to Enb.
·
Roaming Control with the Connection to HSS.
·
A UE can use the Services of only one MME At
Any Given Time!
HSS Functons:
·
Permanent and Central subscriber Database.
·
Stores
Mobility and Service Data For Each Subscriber.
·
Contains Authentication Centre Functionality
also.
EIR Functons:
·
IMEI Validation.
·
MME Interacts with EIR to Validate the IMEI
of a UE.
·
Maintains White, Grey, and Black Lists of
IMEIs.
PCRF Functons:
·
QoS Handling Function
·
QoS Policy Negotiation with PDN
·
Validates the QoS of EPS Bearers Requested by
EPC As well
·
Charging Policy: Determines how the Packets
should be Accounted
·
PCRF to Provide Policy and Charging Rules
Every time a Bearer is Se!
SGW Functons:
·
Packet Data Anchoring Function With in EPC.
·
Receives UL Data From eNB/SGSN and Transmits
to PGW.
·
Receives DL Data From PGW and Transmits to
eNB/SGSN.
·
local Mobility Anchor point for inter-eNodeB
handover.
·
Mobility anchoring for inter-3GPP mobility.
·
“End Marker" Notification to Source eNB
or SGSN after Path Switch.
·
Downlink Packet Buffering and Initiation of
Network Triggered Service.
·
Packet Marking W.R.T QOS Implementation
Required for a EPS Bearer.
·
Bearer Binding Functions.
·
A UE can use the Services of only one SGW At
Any Given Time!
PGW Functons:
·
Packet Data Anchoring Function With in EPC
·
Receives UL Data From SGW And Transmits to
PDN
·
Receives DL Data From PDN and Transmits to
SGW
·
Mobility Anchor point for Non-3GPP Mobility
·
DHCP Function: IP Address Allocation TO UE
·
Deal with PCRF for Finalizing PCC Rule for a
EPS Bearer
·
Packet Marking W.R.T QOS Implementation
Required for a EPS Bearer
·
Policy and Charging Enforcement Function
[PCEF]: Billing Generation
·
Bearer Binding Functions
·
UE Can use Services of Many PDN GWs to
Connect to Multiple PDNs
