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EVERYTHING YOU EVER WANTED TO KNOW ABOUT LTE(BUT WERE AFRAID TO ASK)SEMINAR –
PART 2/2
Jonathan BuschmannEricsson ItalyRome, April 27, 2011
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 2 (23)
Objectives of the seminar Answer these questions
› How have mobile networks evolved over the years? › What are the main performance targets for LTE/SAE? › What is the new core architecture?› How does mobility work in LTE?› How are some key services supported?› What is LTE physical layer like?› How will 3G operators evolve their network?
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 3 (23)
› 1G FDMA (NMT, AMPS, TACS) 80’s - Voice (analog traffic, digital signaling)
› 2G TDMA (GSM, D-AMPS, PDC) and CDMA (IS-95) 90’s - Voice, SMS, CS data transfer ~ 9.6 kbit/s (50 kbit/s HSCSD)
› 2.5G TDMA (GPRS) 00’s - PS data transfer ~ 50 kbit/s
2.75G TDMA (GPRS+EDGE) 00’s - PS data ~ 150kbit/s
› 3-3.5G WCDMA (UMTS) and CDMA 2000 00’s - PS & CS data transfer ~ 14-42 Mbit/s (HSPA/HSPA+), Voice, SMS
› 3.9G OFDMA (LTE/SAE) 10’s - PS Data and Voice (VoIP) ~ 100Mbit/s
› 4G IMT Advanced
History of Mobile Communications
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 4 (23)
• Peak Data Rate
WCDMA comparison(Release 6)
• Peak Spectral Efficiency DL ≥5 bps/Hz UL ≥
2.5 bps/Hz DL = 2.9 bps/HzUL = 1.2 bps/Hz
1.4; 3; 5; 10 ;15; 20 MHz 5 MHz (single layer)• Spectrum Flexibility
• User Plane Latency
UL ≥
50 Mbps (@ 20 MHz) UL = 5.8 Mbps (5 MHz)
DL ≥
100 Mbps (@ 20 MHz) DL = 14.4 Mbps (5 MHz)
< 10 ms (two way latency) 50 ms
• Mobility Speeds up to 350 km/h
• Coverage
Cell radius up to 30 km • Interworking
with existing 2G/3G radio access networks
LTE/SAE Main Targets
• Packet Network >60 VoIP
calls / MHz CS & PS layers
40 voice calls / MHz
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 5 (23)
CN SAE CN (EPC)
RNC RNC
NodeB NodeB e-NodeB e-NodeB
WCDMA LTE/SAE
Moving RNC functions to e-NodeB
UE UE
A flat architecture for optimized performance and cost efficiency
SGSN
GGSN
P/S-GW
Architecture EvolutionTowards a simpler architecture
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 6 (23)
eNB eNB
eNB
MME/S-GW MME/S-GW
S1
X2
X2
X2
SAE (System Architecture Evolution)
LTE (Long Term Evolution)
EPC (Evolved Packet Core)
E-UTRAN
EPS (Evolved Packet System)
UE
EPS Architecture
Uu
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 7 (23)
LTE/SAE USER & CONTROL PLANES
PHY
MAC
RLC
PDCP
RRC
UE
PHY
MAC
RLC
PDCP
eNB
RRC
NAS NAS
CONTROL Plane
MME
Uu
SCTP
S1-AP
IP
L2
L1
SCTP
S1-AP
IP
L2
L1
SCTP
S1-AP
IP
SCTP
S1-AP
L2
IP
SCTP
S1-AP
L1
L2
IP
SCTP
S1-AP
S1-CP
S5/S8
PHY
MAC
RLC
PDCP
IP
UE
PHY
MAC
RLC
PDCP
eNBAPPLICATION
USER Plane
PDN GW
Uu
GTP-U
UDP/IP
L2
L1
SCTP
S1-AP
IP
L2
L1
SCTP
S1-AP
IP
SCTP
S1-AP
L2
IP
SCTP
S1-AP
L1
L2
UDP/IP
GTP-U
IP
S1-UP
Serving GW
GTP-U
UDP/IP
L2
L1
GTP-U
UDP/IP
L2
L1
Peer Entity
S1-AP
L2
L1
S1-APS1-AP
L2
S1-AP
L1
L2
IP
APPLICATION
IP PACKET
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 8 (23)
S1-UP
Internet
eNodeB
Gi
S-GW
P-GW
S5/S8
EPC & E-UTRAN Detailed Architecture
S11MME
S1-CP
eNodeB• Radio Resource Management• Radio Physical layer • Encryption of UP & CP• Measurement ctrl & reporting• Mobility Control
Serving Gateway• Packet routing & forwarding • Mobility anchor• Collecting information for charging• Buffering U-plane packets while paging
PDN Gateway• UE IP Address Allocation• QoS Enforcement• Packet filtering (QoS)• Lawful Interception• Charging (Service)• Non-3GPP Mobilty Anchor • Not seen by terminal
Mobility Management Entity• Idle mode mobility management • EPS Bearer Management (QoS)• Security –
AAA (both data and signalling)• UE attach/detach
eNodeB
E-UTRAN
LTE
MME
S10
Evolved Packet Core
SAE
X2-UP
X2-CP
UE
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 9 (23)
S1-UP
eNodeB
Gi
S-GW
P-GW
S5/S8S4/S11
SGSN/MME
S1-CP
eNodeB
LTE
SAE
X2-UP
X2-CP
UE
Implementation of SAE/LTEIntegration with 2G/3G
Iub
UTRAN
Node B
Iu-CP
BTS
Gb
Abis
BSC
S4-UPIu-UP
RNC
GRAN
3G
Internet
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 10 (23)
User Equipment States
DETACHED• No UE-MME connection• UE not known by MME
REGISTERED(UE attached)
DEREGISTERED(UE not attached)
ATTACH !
CONNECTED• UE-MME connection• Data transfer possible
UE OFF
IDLE• UE-MME connection released
• No data transfer • UE stands by for paging
Signalling Connection release
Signalling Connection re-activation
TA update
DETACH !
eNodeB
MME
UE position known on Cell level in eNB
Handover
eNB
MME Tracking Area (TA)
UE ON (active)UE ON (idle)
UE ON (active)UE OFF
DETACH !
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 11 (23)
S1
X2
Intra-LTE Handover with no MME relocation
Source e-NB
VII
Target e-NB
Gi
MME/S-GW
I
III
II
HANDOVER REQUEST I
HANDOVER REQUEST ACK II
HANDOVER COMMANDIIIVI
HANDOVER CONFIRM V
V
PACKET FORWARDING IV
PATH SWITCH REQUEST VI
PATH SWITCH ACK VII
RELEASE RESOURCE VIII
VIII
IV
Internet
P-GW
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 12 (23)
IP/Ethernet transport
IP/Ethernet transport
Gi
S5
Gi1 2IP PoP
S-GW(2)S-GW(1)S-GW S-GW S-GWS-GW S-GW
P-GW
S10 MMEMMEMME MMEMMEMME
Internet
Handower
in LTE (Inter-pool example)
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 13 (23)
EPS services IP Multimedia Subsystem
› IP Multimedia Subsystem (IMS)› IMS is an all-IP network for multimedia
services › 3GPP standard› SIP – main protocol from IETF› IMS is access independent› The only 3GPP standardized means to
support voice› 3GPP One-Voice
profile promotes IMS
SIP
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 14 (23)
› Application: Mobile TV› Broadcast/Multicast Services ⇒Point-To-Multipoint transmission in downlink
- saves network resources› New entities
–
Broadcast Multicast Service Center (BM-SC) in the IP network–
MBMS Gateway in the EPC Network–
MCE (Multicell Coordination Entity) in the E-UTRAN (may be integrated in the E-NB)BM-SC
Content Provider
EPS servicesMultimedia Broadcast Multicast Service
MCE
E-UTRAN
eNBeNB
MBMS Gateway
EPC
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 15 (23)
LTE PHYSICAL LAYER Multiple Access TECHNIQUES
Frequency Division Multiple Access
Each User has a unique frequency (1 voice channel per user).
All users transmit at the same time
Each User has a unique scrambling code Many users share the same frequency and time
Code Division Multiple Access
Each User has a unique time slot
Several users share the same frequency.
Time Division Multiple Access
time
frequency
timefrequency
frequency
Orthogonal Frequency Division Multiple Access
Each User and has a unique Time and Frequency Resource
Many users are separated in frequency and/or time
1G (i.e.TACS) 2G (i.e. GSM) 3G (i.e. WCDMA) 4G (i.e. LTE)
FDMATDMACDMAOFDMA
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 16 (23)
› Flexible bandwidth
› Uplink: SC-FDMA with dynamic bandwidth
–
Low PAPR Higher power efficiency
–
Reduced uplink interference
› Downlink: Adaptive OFDM–
Channel-dependent scheduling and link adaptation
› Multi-Antennas, both RBS and terminal
–
Interference rejection
–
High bit rates
–
Coverage
TXTX RXRX
time
frequency
time
frequency
› FDD, TDD & Half Duplex TDD
10 15 20 MHz3
fDL
fUL
FDDFDD--onlyonlyfDL
fUL
HalfHalf--duplex FDDduplex FDDfDL/UL
TDDTDD--onlyonly
∆f=15kHz
1 ms
180 kHz
1.4 5
LTE PHYSICAL LAYER MAIN ASPECTS
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 17 (23)
Advanced Antenna Communications–
Tx & Rx Diversity
–
Multi-Layer Transmission (Spatial Multiplexing)
–
Beam-Forming
TX
TX
MIMO 2x2 ⇒ channel capacity x ~ 2
MIMO 4x4 ⇒ channel capacity x ~ 4
LTE PHYSICAL LAYER MULTI ANTENNA TECHNIQUEs
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 18 (23)
e-NB
Example of Spatial Multiplexing
Layer 1
Layer 2
Layer 2
UE
LTE PHYSICAL LAYER MULTI ANTENNA TECHNIQUES
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 19 (23)
› Bandwidth flexibility LTE physical-layer specification supports any bandwidth in the range 6 RBs to 100 RBs in steps of one RB
6 RB (≈1.1 MHz)
100 RB (≈20 MHz)
› Radio requirements only specified for a limited set of bandwidths
› Relatively straighforward to extend to additional bandwidths
› All UEs must support the maximum bandwidth of each supported band
LTE PHYSICAL LAYER RF Spectrum flexibility
10 15 20 MHz31.4 5
› Radio requirements only specified for a limited set of bandwidths
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 20 (23)
Category 1 2 3 4 5
DL peak rate 10 50 100 150 300
UL peak rate 5 25 50 50 75
Max DL mod 64QAM
Max UL mod 16QAM 64QAM
Layers for spatial mux. 1 2 4
› All UEs support 4 Tx antennas at eNodeB› Soft buffer sizes under discussion› MBMS is a separate capability› FDD, HD-FDD and TDD are independent capabilities
LTE Devices
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 21 (23)
Simple deployment & Management Automated Neighbor Relations (ANR)
Cell ANcell list;- CGI 17- CGI 22
Cell BPCI = 5CGI =19
X2
UE
OSS-RC
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 22 (23)
Simple deployment & Management Node selection
› DNS used for node selection
› EPS uses S-NAPTR (RFC 3958) to map services and protocols (i.e. interfaces) to CNAMEs
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 23 (23)
What frequencies for LTE?
› First deployments in Europe in 2.6 GHz band (Sweden and Norway)
› Most “appetizing” band is the Digital Dividend – 800 MHz› Re-farming of UMTS and GSM bands also will happen
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 24 (23)
What frequencies for LTE? In italy
› Re-farming for 900 MHz already agreed:–
TI, VFE, WIND: 10 MHz
–
Extra 5 MHz destined to H3G
› AGCOM just announced preliminary rules and public consultation for auction for 800, 1800, 2000 and 2600
–
Single auction for all spectrum–
1800 spectrum liberated by DoD and GSM (25 MHz FDD)
–
2000 (UMTS TDD band left from IPSE)–
2600 (70 MHz)
–
800 (digital dividend)
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 25 (23)
MetroAccess Core
RNC
Mobile Broad Band State of the Art & Evolution
Fibre/MW
CopperIub
ATM
xDSL
Microwave
WCDMAIub
ATM
PDH
RNC
MSC
CS core
PS core
SGSNGGSN
MGW
Node B
e-Node B
OFDMA/SC-FDMA up to nx100 Mbpsw MIMO (n=2, 3)
S1 /X2
IP
ETH
Node B
LTELong Term Evolution
P/S-GWSGSN/MME
SAESystem Architecture Evolution
EPCWCDMA
HSPA/HSPA+up to 14/42 Mbps
Iub
ATM
PDH
Iub
IP
ETH
IP Network
ETH
SDH
ATM
SDH
IP TRANSFORMATIONHSPA EVOLUTIONLTE/SAE Transformation
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 26 (23)
references
› SAE and the Evolved Packet Core (Academic Press)–
Magnus Olsson, Shabnam Sultana, Stefan Rommer, Lars Frid, Catherine Mulligan
› 3G Evolution: HSPA and LTE for Mobile Broadband (Academic Press)
–
Erik Dahlman, Stefan Parkvall, Johan Skold, Per Beming
› 4G LTE/LTE-Advanced for Mobile Broadband (Academic Press)
–
Erik Dahlman, Stefan Parkvall, Johan Skold
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 27 (23)
Everything You Ever Wanted to Know About LTE | Public | © Ericsson AB 2011 | 2011-03-15 | Page 28 (23)
ATM Asynchronous Transfer Mode
CS Core Circuit Switched Core
e-Node B Evolved Node B (refers to LTE Access Network)
DNS Domain Name System
EPC Evolved Packet Core
EPS Evolved Packet System
E-UTRAN Evolved UMTS Radio Access Network
HSPA High Speed Packet Access (UMTS Broadband Technology)
IMS IP Multimedia Systems
LTE Long Term Evolution (refers to radio interface and network functionalities evolution in RAN)
OFDM Orthogonal Frequency Division Multiplexing
OFDMA Orthogonal Frequency Division Multiple Access
MBMS Multimedia Broadcast Multicast Service
MIMO Multiple Input Multiple Output (multiple port antenna systems both at Node B and User Equipment)
PS Core Packed Switched Core
SAE System Architecture Evolution (refers to Core network evolution)
Acronyms