GSM TOWARDS LTE NETWORKS
Lecture # 6
LTE
Many names ...
LTE - Long Term Evolution eUTRAN
SAE - System Architecture Evolution EPS (Evolved Packet System)
Introduction
LTE/SAE
What is 3GPP? 3GPP stands for 3rd Generation Partnership Project It is a partnership of 6 regional SDOs (Standards Development Organizations)
These SDOs take 3GPP specifications and transpose them to regional standards
Japan
USA
Towards LTE
LTE Access LTE radio access
Downlink: OFDM Uplink: SC-FDMA
Advanced antenna solutions Diversity Beam-forming Multi-layer transmission
(MIMO)
Spectrum flexibility Flexible bandwidth New and existing bands Duplex flexibility: FDD and
TDD
20 MHz1.4 MHz
TX TX
SC-FDMA
OFDMA
Terminology Updates
EPC = Evolved Packet core (earlier SAE=System Architecture Evolution).
e UTRAN = Evolved UTRAN (earlier LTERAN = Long Term Evolution).
EPS = Evolved Packet Systems including EPC and Terminals.
LTE Offer’s
Performance and capacity
DL 100 Mbps AND UL 50 Mbps
Simplicity
Flexible Bandwidths (5Mhz-20Mhz),
FDD and TDD
plug-and-play Devices
self-configuration Devices
self-optimization Devices
LTE (Long Term Evolution) Radio Side (LTE – Long Term Evolution)
Improvements in spectral efficiency, user throughput, latency
Simplification of the radio network Efficient support of packet based services
Network Side (SAE – System Architecture Evolution) Improvement in latency, capacity, throughput Simplification of the core network Optimization for IP traffic and services Simplified support and handover to non-3GPP access
technologies
LTE Objectives Reduced cost per bit
Improve spectrum efficiency ( e.g. 2-4 x Rel6) Reduce cost of backhaul (transmission in UTRAN)
Increased service provisioning – more services at lower cost with better user experience
Focus on delivery of services utilising ”IP” Reduce setup time and round trip time Increase the support of QoS for the various types of services
(e.g. Voice over IP) Increase peak bit rate (e.g. above 100Mbps DL and above
50Mbps UL) Allow for reasonable terminal power consumption
Evolution Path Architecture
The pay load is to be directed to a tunnel (eUTRAN)
Payload goes directly from the evolved node B to the Gateway
Control plane is directed at the Mobility management end.
LTE
Core Nodes of LTE Serving GPRS Support Node (SGSN) - to provide connections for
GERAN (GSM Radio Access Network) and UTRAN Networks (UMTS Terrestrial Radio
Access Network) Serving Gateway - to terminate the interface toward the 3GPP radio-access networks
PDN Gateway - to control IP data services like routing, addressing, policy enforcing and providing access to non-3GPP access networks
Mobility Management Entity (MME) - to manage control plane context, authentication and authorization
3GPP anchor - to manage mobility for 2G/3G and LTE systems
SAE anchor - to manage mobility for non 3GPP RATs
Policy Control and Charging Rules Function (PCRF) - to manage Quality of Service (QoS) aspects
PDN GWServing GW
MME
S1-MME S1-U
LTE
IP networks
eNodeB
SGSN
Iu CPGb
2G 3G
S3
BSC
BTS
RNC
Node B
HLR/HSS
PCRF
Iu UP
S11
Gr
S10
S6a
SGi
X2
Iur
S7
Non-3GPP access
S2a/b
The PDN and Serving GW may be separate nodes in some scenarios
(S5 in-between)Only PS Domain shown
S4
From 3GPP to LTE/SAE
PDN Gateway - to control IP data services like routing, addressing, policy enforcing and providing access to non-3GPP access networks
MME Functionality Roaming (S6a towards home HSS) Authentication SAE GW selection Idle mode mobility handling
Tracking Area Update Paging
Mobility handling of inter-MME (pool) handover (triggered by eNodeB) inter-RAT handover (triggered by eNodeB)
QoS “negotiation” with UE and eNodeB Security
Ciphering and integrity protection of NAS signalling Secure control signalling transport on S1 interface (unless taken care of
by a SEG (Security Gateway)) O&M security (?)
SAE CN ArchitectureSGi
MME
S1-MME S1-U
S11
X2
S10
eNodeB
S3
S4
SGSNSAE GW
SAE GW Functionality PDN SAE GW:
Policy Enforcement Per-user based packet filtering (by e.g. deep packet inspection) Charging Support User plane anchor point for mobility between 3GPP accesses and non-3GPP accesses routing of user data towards the S-GW Security
O&M security (?) Lawful Intercept
Serving SAE GW: User plane anchor point for inter-eNB handover (within one pool) User plane anchor point for inter-3GPP mobility routing of user data towards the eNodeB routing of user data towards the P-GW routing of user data towards the SGSN (2G and 3G) or RNC (3G with “Direct Tunnel”) Security
Secure user data transport on S1 interface (unless taken care of by a SEG (Security Gateway)) O&M security (?)
Lawful Intercept
The PDN SAE GW and the Serving SAE GW may be implemented in one physical node or separated physical nodes.
…
SAE CN ArchitectureSGi
MME
S1-MME S1-U
S11
X2
S10
eNodeB
S3
S4
SGSNSAE GW
Why LTE/SAE?Driving Factors for LTE/SAE
Ensuring that 3G is attractive in comparison with competing technologies (WiFi, WiMax, Flarion, …)
LTE/SAE architecture Competing technologies looks simpler (fewer nodes) OPEX (fewer node types to manage)
Significantly increased peak data rate Competing technologies provide higher data rates End-user experience
Reduced user plane latency Necessary to achieve increased data rates End-user experience
Significantly reduced control plane latency End-user experience
Improved Performance(compared to WCDMA)
Introduction
Perception
LTE – Performance Targets High data rates
Downlink: >100 Mbps Uplink: >50 Mbps Cell-edge data rates 2-3 x HSPA Rel. 6 (@ 2006)
Low delay/latency User plane RTT: Less than 10 ms ( RAN RTT ) Channel set-up: Less than 100 ms ( idle-to-active )
High spectral efficiency Targeting 3 X HSPA Rel. 6 (@ 2006 )
High performance for broadcast services
Spectrum flexibility Operation in a wide-range of spectrum allocations Wide range of Bandwidth Support for FDD, Half-duplex FDD and TDD Modes
Cost-effective migration from current/future 3G systems
Focus on services from the packet-switched domain !
Introduction
LTE/SAE Architecture
LTE/SAE Architecture (release 8)Functional changes compared to the current UMTS Architecture
Moving all RNC functions to the Node B ……, SGSN CP functions to the MME, and GGSN functions to the SAE GW.
GGSN
SGSN
RNC
P-GWS-GW
PDN GateWay Serving GateWay
Node B / HSPA eNodeB
MME Mobility Management Entity(not user plane functions)
LTE/SAE Architecture
LTE Architecture
eNB eNB
eNB
MME/UPE MME/UPE
S1
X2
X2
X2
EPC
E-UTRAN
Evolved Packet Core
MME/UPE = Mobility Management Entity/User Plane Entity
eNB = eNodeB
Evolved Packet Switching Network Architecture
MMEMME
P-GW/S-GWP-GW/S-GW
MMEMME MMEMME
P-GW/S-GWP-GW/S-GW P-GW/S-GWP-GW/S-GW P-GW/S-GWP-GW/S-GW
LTE NODE B LTE NODE B LTE NODE B
LTE NODE BLTE NODE B
S11
S1-Cp
X2
Gi
Interfaces
Air Interface
E
P
C
EUTRAN
LTE/SAE ArchitectureMain SAE interfaces (non-roaming case)
S1-MME S1-U
IP networks
S3 S11
S10
SGi
S4
S5/S8
(SGi)
X2
SAE CN Architecture
OSS-RC
S1-MME: control plane protocol between eNodeB and MME
S1-U: user plane tunneling interface between eNodeB and Serving GW
S5: user plane tunneling interface between Serving GW and PDN GW
S8: user plane tunneling interface between Serving GW and PDN GW for roaming
S10: control plane interface between MME and MME
S11: control plane interface between MME and Serving GW.
S4: *)user plane tunneling interface between SGSN and PDN GW
S3: *)control plane interface between MME and SGSN.
O&M interfaces: OSS-RC – MME OSS-RC – SAE GW
Note: Interfaces non-3GPP accesses not covered.
SAE GWMME
eNodeB
SGSN
SAE GW(in some usecases only)
2G Towards 3G Networks
GGSN
IP networks
SGSN
IuGb
2G 3G
BSC
BTS
RNC
Node B
HLR
PCRFGr
Gi
Iur
Gx
Only PS Domain shown
Gn Gn
•Policy Control and Charging Rules Function (PCRF) - to manage Quality of Service (QoS) aspects
GGSN
IP networks
SGSN
Iu CPGb
2G 3G
BSC
BTS
RNC
Node B
HLR/HSS
PCRF
Iu UP
Gr
Gi
Iur
Gx
Only PS Domain shown
Gn
Optimizing the 3G/HSPA payload plane for Broadband traffic
HSPA (Higher Speed Packet Access)
10 Mb/s
From 3GPP Release 6 to LTE/SAE Improving performance with LTE/SAE; 3GPP Release 8
PDN GWServing GW
MME
S1-MME S1-U
LTE
IP networks
eNodeB
SGSN
Iu CPGb
2G 3G
S3
BSC
BTS
RNC
Node B
HLR/HSS
PCRF
Iu UP
S11
Gr
S10
S6a
SGi
LTE/SAE Architecture
X2
Iur
S7
Non-3GPP access
S2a/b
The PDN and Serving GW may be separate nodes in some scenarios
(S5 in-between)
A flat architecture for optimized performance and cost efficiency
Only PS Domain shown
(Additions/changes in red.)
S4
LTE/SAE Architecture Product dimension
PDN GWServing GW
MME
S1-MME S1-U
LTE
IP networks
eNodeB
SGSN
Iu CPGb
2G 3G
S3
BSC
BTS
RNC
Node B
HLR/HSS
PCRF
Iu UP
S11
Gr
S10
S6a
SGi
LTE/SAE Architecture
X2
Iur
S7
Non-3GPP access
S2a/b
S4PDN GW
Serving GW
”Gateway”
MMESGSN
”Mobility Server”
PCRF
HLR/HSS
”HLR/HSS”
EPC
eNode B
RBS
OSS
PA/DU Core & IMS
PA/DU Radio
+ True high-speed mobile data
+ Full-motion HD video anywhere
+ Stream any content
+ Mobile peer2peer & Web 2.0
(Networking)
+ Triple play
EDGE
EVDO-AHSDPA
LTEFiber
ADSL-2+
ADSL
Mbps
40-100MbpsFiber like speed on mobile
Comparison with Speed
+ Spectral efficiencyBetter utilization of spectrum available
+ Low frequency, Advanced Receivers and Smart AntennaFor improved coverage and reduced cost of ownership
+ Increased CapacityMuch higher user and sector throughput for lower individual cost service delivery
+ Simpler RAN, IP Core & Centralized service deliveryFewer nodes & interfaces (Node-B/RNC/Gateway) One Network & IMS for all access technologies
+ Connect to legacy coresExisting network asset investment protection
+ 3GPP/2 Market tractionEconomy of scale
LTE VoIP cost*
UMTS rel.99 voice call cost$
10%
3GPP subscribers 85% market share
Predicted LTE VoIP voice call cost* - Sound Partners Limited Research
Comparison Cost
10-5msec latencyHighly Responsive Multimedia
+ Improved user experience
+ Fast VoIP call set-up
+ Instantaneous web pages
+ Streaming fast buffering
+ Online mobile gamingEDGE
EVDO-AHSDPA
LTEFiber
ADSL-2+
ADSL
Response Time
LTE Time Line
3G- R’993G- R’99HSPAHSPA
HSPA EvolutionHSPA Evolution
LTELTE
2002 2005 2008/2009 2009
384 kbps 3.6 Mbps 21/28/42 Mbps ~150 MbpsPeak rate
2007
7/14 Mbps
Mobile broadband speed evolution
LTE EvolutionLTE Evolution
2013
1 Gbps
Target
www.lte.yolasite.com
Thanks