Transcript UMTS

Mobile Communications:
Long Term Evolution
Part 1
Part 2
• Motivation for LTE
• Evolution of the standards
• Requirements and targets
• Competing standards
• Frequency bands
• System architecture
• LTE enabling technologies
– OFDM
– MIMO
– SC-FDMA
Motivation for LTE
• For consumers
– Fast data access (several megabytes in just some seconds)
– Flexible media access (access to any media content from everywhere)
– Real time services (streaming, VoIP, videoconferencing, etc.)
• For network operators
– Flexibility (scalable bandwidth from 1.25MHz to 20MHz)
– Efficiency (more standard voice customers, more data, more services)
– Cost savings (cheaper infrastructure, migration to an All-IP-Network)
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 2
Chair Systems
www.tu-cottbus.de/systeme
IMT-2000 to IMT-Advanced
(source: ITU-R M. 1645)
Mobility
New
Mobile
Access
High
IMT-2000
new capabilities of
systems beyond
IMT-2000
Enhanced
IMT-2000
IMT-A
Enhancement
New Nomadic / Local
Area Wireless Access
Low
1
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
10
100
Page 3
1000
Peak useful
datarate (Mbps)
Chair Systems
www.tu-cottbus.de/systeme
Cellular wireless system evolution
4G
3.9G
3.5G /
3.75G
2.5G /
2.75G
2G
1G
Analog
Cellular
·
·
Voice
AMPS, TACS
Digital
Cellular
·
·
·
·
·
Voice
Pager
10kbps data
3GPP: GSM
3GPP2: cdmaOne
Digital
Cellular
·
·
·
·
·
·
·
Voice
E-mail
Photos
·
Web
·
~100kbps data
3GPP: GPRS, EDGE
3GPP2: CDMA 2000 1x
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
·
·
·
Wide-Band
Digital
Cellular
·
·
·
·
Wide-Band
Digital
Cellular
Wide-Band
Digital
Cellular
3G
Video
Mobile broadband
3GPP: HSPA
(HSDPA / HSUPA)
3GPP2: CDMA 2000
1x EV-DO Rev. A / B
IEEE: Mobile WiMAX
(IEEE 802.16e)
Video
·
M-pixel cam.
·
3D
300kbps
14Mbps
3GPP: W-CDMA (UMTS)
3GPP2: CDMA 2000 1x EV-DO
Page 4
Wide-Band
Network
·
·
·
·
·
·
·
·
Video
High-end gaming
100Mbps, 10msec
Flexible bandwidth
All IP Network
3GPP: Super 3G / LTE
3GPP2: UMB
IEEE: Mobile WiMAX
(802.16e)
·
·
·
·
·
·
·
·
Ubiquitous data
Flexible Spectrum use
Enhanced apps.
100Mbps – 1Gbps
OFDM
Meet IMT-A requirements
3GPP: LTE-A
IEEE: 802.16m
Chair Systems
www.tu-cottbus.de/systeme
Evolution of UMTS towards packet
only system
Release
Rel-99
Rel-4
Rel-5
Rel-6
Rel-7
Functional
freeze
Mar 2000
Mar 2001
Jun 2002
Mar 2005
Dec 2007
Rel-8
Dec 2008
Main features of release
·
·
·
·
·
·
·
·
·
Basic 3.84 Mcps W-CDMA (FDD & TDD)
1.28 Mcps narrow band version of W-CDMA (TD-SCDMA)
HDSPA as packet-based data services for UMTS
Completion of packet data service with HSUPA (E-DCH)
first work on LTE / SAE with completion of feasibility studies
HSPA+ (downlink MIMO, 64QAM downlink, 16QAM uplink)
LTE work item – OFOMA/SC-FDMA air interface
SAE work item – new IP core network
HSPA features (dual cell HSDPA, 64QAM with MIMO)
• First version of LTE is documented in 3GPP specifications Rel-8
• Former specifications of LTE are known as E-UTRA and E-UTRAN
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 5
Chair Systems
www.tu-cottbus.de/systeme
Requirements and targets
(source: TR 25.912 and 25.913)
• Peak data rate
FDD downlink peak data rates (64QAM, 20MHz bandwidth)
Antenna configuration
SISO
2x2 MIMO
4x4 MIMO
Peak data rate Mbps
100
172.8
326.4
FDD uplink peak data rates (single antenna, 20MHzandwidth)
Modulation depth
QPSK
16QAM
64QAM
Peak data rate Mbps
50
57.6
86.4
• Latency
 C-Plane latency: less than 100ms camped-to-active transition and less
than 50ms dormant-to-active transition (excluding DL and paging delay)
 U-Plane latency: less than 5ms in upload condition
• Capacity
 at least 200 active users per cell for spectrum allocations up to 5 MHz
 at least 400 users for higher spectrum allocations
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 6
Chair Systems
www.tu-cottbus.de/systeme
Requirements and targets
(source: TR 25.913)
• Average user throughput per MHz and spectrum efficiency
 DL: 3 to 4 times Release 6 HSDPA.
 UL: 2 to 3 times Release 6 Enhanced Uplink
• Mobility
 Optimized for low mobile speed at 0 – 15km/h
 Support 15 – 120km/h with high performance
 120 – 350km/h main mobility (500km/h depending on frequency band)
• Coverage
 Up to 5km: meet targets for throughput, spectrum efficiency and mobility
 Up to 30km: support full mobility, slight degradations of throughput and
more significant degradation of spectrum efficiency are acceptable
• Further enhanced MBMS
 Improved cell edge performance
 Defined interruption time when changing between different streams
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 7
Chair Systems
www.tu-cottbus.de/systeme
Requirements and targets
(source: TR 25.913)
• Deployment Scenarios
 Standalone (no interworking with UTRAN/GERAN)
 Integrated (existing UTRAN and/or GERAN in same geographical area)
• Spectrum flexibility
 Support for spectrum allocations of different size (1.25 (1.4?) – 20MHz)
 Support for diverse spectrum arrangements
• Spectrum deployment
 Co-existence and co-location with GERAN/3G and between operators
on adjacent channels
• Co-existence and interworking with 3GPP RAT
 Interruption time during handover between E-UTRAN and 3GPP-RAN
(real-time service < 300msec, non real-time service < 500msec)
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 8
Chair Systems
www.tu-cottbus.de/systeme
Requirements and targets
(source: TR 25.913)
• Architecture and migration
 Single E-UTRAN architecture (packet based)
 Simplified and minimized number of interfaces
 Minimized delay variation (jitter)
• Radio resource management requirements
 Enhanced end-to-end QoS
 Support efficient transmission and operation of higher layer protocols
over the radio interface (e.g. IP header compression)
 Support of load sharing and policy management across different Radio
Access Technologies
• Complexity
 Minimized number of options
 No redundant mandatory features
 Optimized terminal complexity and power consumption
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 9
Chair Systems
www.tu-cottbus.de/systeme
Parameters in context
(source: www.radio-electronics.com)
WCDMA
HSPA
HSPA+
(UMTS) HSDPA / HSUPA
Maximum downlink speed
384 kbps
14 Mbps
28 Mbps
Maximum uplink speed
128 kbps
5.7 Mbps
11 Mbps
Latency round trip time approx. 150 ms
100 ms
50 ms (max)
3GPP releases
Rel 99/4
Rel 5/6
Rel 7
Approx. years of initial roll out
2003/4
2005/6 HSDPA
2008/9
2007/8 HSUPA
Access methodology
CDMA
CDMA
CDMA
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 10
LTE
100 Mbps
50 Mbps
~10 ms
Rel 8
2009/10
DL: OFDMA
UL: SC-FDMA
Chair Systems
www.tu-cottbus.de/systeme
Complementary Access Systems
Some existing standards and
technologies for the different layers
IEEE 802.16
3GPP LTE
3GPP2 UMB/
IEEE 802.20
IEEE 802.21
IEEE 802.11
Bluetooth*
IEEE 802.15
UWB
mmWave
IEEE 802.3
Source ITU-R M.1645
Switching between the layers need to be transparent to the user
Monday, 11 April 2016
winter
11 term 2010/11 – Mobile Communication Systems II
Page 11
Chair Systems
www.tu-cottbus.de/systeme
Competing 3.9G standards
• Different organizations - different standards?
– 3GPP: LTE
– 3GPP2: UMB (discontinued)
– IEEE and WiMAX Forum: Mobile WiMAX™ (IEEE 802.16e)
• All have similar goals
– Improved spectral efficiency
– Wide bandwidth
– Very high data rates
• Goals shall be achieved primarily by
– Higher-order modulation schemes
– Multi-antenna technology
– Simplified network architecture
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 12
Chair Systems
www.tu-cottbus.de/systeme
Comparison of the competitors
(source: Technical overview of 3GPP LTE by Hyung G. Myung in May 2008)
3GPP LTE
3GPP2 UMB
Mobile WiMAX R1 (802.16e)
5, 7, 8.75, 10 MHz
OFDMA
OFDMA
TDD
localized, distributed
yes
QPSK, 16QAM, 64QAM
10.94 kHz
512
target: up to 120 km/h
convolutional and
convolutional turbo, block
turbo and LDPC (optional)
beamforming, space-time
coding and spatial multiplexing
Channel bandwidth
DL multiple access
UL multiple access
Duplexing
Subcarrier mapping
Subcarrier hopping
Data modulation
Subcarrier spacing
FFT size (5 MHz)
Mobility support
Channel coding
1.4, 3, 5, 10, 15, 20 MHz
OFDMA
SC-FDMA
FDD, TDD
localized
yes
QPSK, 16QAM, 64QAM
15 kHz
512
target: up to 350 km/h
convolutional, turbo
1.25, 2.5, 5, 10, 20 MHz
OFDMA
OFDMA, CDMA
FDD, TDD
localized, distributed
yes
QPSK, 8PSK, 16QAM, 64QAM
9.6 kHz
512
target: up to 300 km/h
convolutional, turbo, LDPC
MIMO
multi-layer precoded spatial
multiplexing, space-time /
frequency block coding,
switched transmit diversity and
cyclic delay diversity
multi-layer precoded spatial
multiplexing, space-time
transmit diversity, spatial
division multiple access and
beamforming
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 13
Chair Systems
www.tu-cottbus.de/systeme
E-UTRA operating bands
(source: TS 36.101)
E-UTRA
Operating
Band
Downlink (DL) operating band
BS transmit
UE receive
FDL_low – FDL_high
2110 MHz – 2170 MHz
1930 MHz – 1990 MHz
1805 MHz – 1880 MHz
2110 MHz – 2155 MHz
869 MHz – 894MHz
875 MHz – 885 MHz
2620 MHz – 2690 MHz
925 MHz – 960 MHz
1844.9 MHz – 1879.9 MHz
2110 MHz – 2170 MHz
1475.9 MHz – 1495.9 MHz
728 MHz – 746 MHz
746 MHz – 756 MHz
758 MHz – 768 MHz
734 MHz – 746 MHz
Duplex
Mode
1
2
3
4
5
6
7
8
9
10
11
12
13
14
17
Uplink (UL) operating band
BS receive
UE transmit
FUL_low – FUL_high
1920 MHz – 1980 MHz
1850 MHz – 1910 MHz
1710 MHz – 1785 MHz
1710 MHz – 1755 MHz
824 MHz – 849 MHz
830 MHz – 840 MHz
2500 MHz – 2570 MHz
880 MHz – 915 MHz
1749.9 MHz – 1784.9 MHz
1710 MHz – 1770 MHz
1427.9 MHz – 1447.9 MHz
698 MHz – 716 MHz
777 MHz – 787 MHz
788 MHz – 798 MHz
704 MHz – 716 MHz
33
34
35
36
37
38
39
40
1900 MHz – 1920 MHz
2010 MHz – 2025 MHz
1850 MHz – 1910 MHz
1930 MHz – 1990 MHz
1910 MHz – 1930 MHz
2570 MHz – 2620 MHz
1880 MHz – 1920 MHz
2300 MHz – 2400 MHz
1900 MHz – 1920 MHz
2010 MHz – 2025 MHz
1850 MHz – 1910 MHz
1930 MHz – 1990 MHz
1910 MHz – 1930 MHz
2570 MHz – 2620 MHz
1880 MHz – 1920 MHz
2300 MHz – 2400 MHz
TDD
TDD
TDD
TDD
TDD
TDD
TDD
TDD
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
FDD
FDD
FDD
FDD
FDD
FDD
FDD
FDD
FDD
FDD
FDD
FDD
FDD
FDD
FDD
Page 14
FDD LTE frequency bands
- Paired bands for simultaneous
transmission on UL and DL
- Separation reduces the impact
of signals to the receiver
performance
TDD LTE frequency bands
- Unpaired because UL and DL
share the same frequency but
time separated
Overlapping frequency bands
- (roaming) UE needs to detect
whether to use TDD or FDD on
a particular band
Chair Systems
www.tu-cottbus.de/systeme
Additional information
(source: www.radio-electronics.com)
1
2
3
4
5
6
7
8
9
10
11
12, 13, 14
15, 16
17
20
21
24
FDD
Description
IMT Core Band (one of the paired bands defined for 3G UTRA and 3GPP Rel-99)
PCS 1900
GSM 1800
AWS (US & other, DL overlaps with DL for band 1 this facilitates roaming)
850
850 (Japan)
IMT Extension
GSM 900
1700 (Japan, overlaps with band 3 but has different band limits, enables roaming to be achieved more easily
3G Americas (extension to band 4, not available everywhere but allocated globally, increases bandwidth from 45 to 60 MHz (paired))
(Japan, also allocated globally to the mobile service on a co-primary basis)
(previously for broadcasting, released as a result of the “digital dividend”, reversed duplex)
(defined by ETSI for Europe, not adopted by 3GPP, combines two nominally TDD bands to provide one FDD band)
(previously for broadcasting, released as a result of the “digital dividend”)
(reversed duplex)
(Japan, also allocated globally to the mobile service on a co-primary basis)
(reversed duplex)
Band
33, 34
35, 36
37, 38
39, 40
TDD
Description
TDD 2000 (defined for unpaired spectrum in Rel 99 of the 3GPP specifications)
TDD 1900
PCS Center Gap (center band spacing between UL and DL pairs of LTE band 7)
IMT Extension Center Gap
Band
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 15
Chair Systems
www.tu-cottbus.de/systeme
Frequency division in Germany
(source: www.bundesnetzagentur.de 30.8.2010)
Frequency bands at 800 MHz and 900 MHz
12,4
MHz
GSM-R
5
5
MHz MHz
FDD-uplink
12,4
MHz
MHz
12,4
MHz
959,9
FDD-uplink
5
5
MHz MHz
925,1
FDD-downlink
GSM-R
918,1
5
5
5
5
5
5
MHz MHz MHz MHz MHz MHz
914,9
B-F
5
5
5
5
5
5
MHz MHz MHz MHz MHz MHz
880,1
A
873,1
862,0
B-F
837,0
832,0
821,0
796,0
791,0
790,0
A
12,4
MHz
FDD-downlink
Frequency bands at 1,8 GHz
E
5
5
MHz MHz
FDD-uplink
17,4
MHz
5,4
MHz
5
MHz
MHz
D
1875,5
5
5
5
MHz MHz MHz
1858,1
A-C
17,4
MHz
1853,1
5
MHz
1830,1
5,4
MHz
1825,1
17,4
MHz
1820,0
E
5
5
MHz MHz
1805,0
1780,5
D
1763,1
1758,1
1735,1
1730,1
1725,0
1710,0
A-C
5
5
5
MHz MHz MHz
17,4
MHz
FDD-downlink
Frequency bands at 2 GHz
D
4,95 4,95
MHz MHz
9,9
MHz
MHz
2170,0
2169,7
C
9,9
MHz
2149,9
2144,95
B
4,95 4,95
MHz MHz
TDD / FDDuplink (extern)
FDD-uplink
2140,0
A
9,9
MHz
2130,1
2125,15
2120,2
14,2
MHz
2110,3
2110,0
D
2025,0
9,9
MHz
2024,7
2010,0
9,9
MHz
2010,5
D
4,95 4,95
MHz MHz
1980,0
1979,7
TDD/
FDD-uplink (extern)
C
9,9
MHz
1959,9
B
4,95 4,95
MHz MHz
1954,95
A
9,9
MHz
1950,0
1940,1
1935,15
1930,2
5
5
5
5
MHz MHz MHz MHz
1920,3
1920,1
1905,1
1900,1
1900,0
E
9,9
MHz
FDD-downlink
Frequency bands at 2,6 GHz
MHz
2690,0
2620,0
2570,0
2500,0
A-N
O-X
A-N
5
5
5
5
5
5
5
5
5
5
5
5
5
5
MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz
5
5
5
5
5
5
5
5
5
5
MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz
5
5
5
5
5
5
5
5
5
5
5
5
5
5
MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz MHz
FDD-uplink / TDD
TDD / FDD-downlink (extern)
FDD-downlink / TDD
Telekom Deutschland
E-Plus-Gruppe
Telefónica O2 Germany
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Vodafone
Page 16
konkret vergeben
abstrakt vergeben
Chair Systems
www.tu-cottbus.de/systeme
LTE network coverage in
Germany (December 2011)
•
•
E-Plus-Group (intended
network expansion)
Source: http://offensivenetzausbau.redaktionsserv
ice-eplus-gruppe.de/4gdatennetz.php
•
•
Vodafone
Source: www.vodafonelte.de/zumonlineshop/netzabdeckun
g/vodafone-ltenetzabdeckung.htm)
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 17
•
•
•
Telekom Deutschland
Source: http://www.tmobile.de/funkversorgung/inland/0,
12418,15400-_,00.html)
Telefónica O2 Germany
(no map provided)
Chair Systems
www.tu-cottbus.de/systeme
2G and 3G cellular network today
(source: TR 23.882)
TE
MT
R
MSC
GERAN
HLR/AuC*
HSS*
EIR
C
SMS-GMSC
SMS-IWMSC
SMS-SC
Um
Gs
Gd
Gf
Iu
TE
MT
R
Rx+ (Rx / Gq)
Gr
Gb, Iu
PCRF
Gx+ (Go / Gx)
Gc
Gmb
SGSN
The 3GPP project
“System Architecture
Evolution” (SAE)
shall simplify this
complex architecture
by defining an all-IP
network called the
Evolved Packet
Core (EPC).
•
The EPC is required
for specific features
of LTE
•
The EPC supports
LTE, UTRAN,
GERAN and non3GPP radio access
networks such as
cdma2000, 802.16
Gi
GGSN
PDN
Mb
Uu
Gn
Ga
Billing
system*
Ga
Mb
Gy
IMSMGW
MRFP
SGSN
UE
•
BM-SC
Gi
Gn / Gp
UTRAN
AF
Wi
OCS*
CGF*
Gm
IMS
P-CSCF
CSCF
Mw
Cx
HLR/
AuC*
CDF
D / Gr
Wf
WLAN Access
Network
Wu
3GPP AAA
Server
OCS*
Wo
Wy
Wm
Wa
Ww
SLF
Dw
Wd
Wa
WLAN
UE
HSS*
Wx
Wf
3GPP AAA
Proxy
Intranet/
Internet
Dx
WAG
Wn
**
Wg
PDG
Wp
Traffic and signaling
Signaling
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Wz
CGF*
Page 18
Billing
system*
* Elements duplicated for
picture layout purposes
only, they belong to the
same logical entity in the
architecture baseline
** is a reference point
currently missing
Chair Systems
www.tu-cottbus.de/systeme
Logical high level architecture
(source: TR 23.882)
GERAN
Gb
GPRS Core
SGSN
PCRF
Rx+
Iu
UTRAN
S7
S3
S4
HSS
S5a
Evolved RAN
(LTE)
S1
MME
UPE
S5b
3GPP
anchor
S6
SAE
anchor
Op.
IP
Serv.
(IMS,
PSS,
etc …)
SGi
S2b
ePDG
Trusted non 3GPP
IP access
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
WLAN
Access NW
Page 19
• User Plane Entity (UPE)
manages and stores UE
context, DL UP termination in
LTE_IDLE, ciphering, mobility
anchor, packet routing and
forwarding, initiation of paging
• 3GPP anchor is the mobility
anchor between 2G/3G and
LTE access systems
S2a
Evolved Packet Core
(SAE)
• Mobility Management Entity
(MME) manages and stores
the UE control plane context,
generates temporary Id, UE
authentication, authorisation
of TA/PLMN, mobility
management
WLAN
3GPP IP
access
• SAE anchor is the mobility
anchor between 3GPP and
non 3GPP access systems
(WLAN, WiMAX, etc.)
Chair Systems
www.tu-cottbus.de/systeme
Interfaces
(source: TS 23.401)
•
S1:
– S1-MME is reference point between E-UTRAN and MME
– S1-U is reference point between E-UTRAN and Serving GW for per bearer U-Plane
tunneling and inter eNB path switching during handover
•
S2: mobility support between WLAN 3GPP IP access or non 3GPP access
•
S3: user and bearer information exchange for inter 3GPP access system mobility
•
S4: control and mobility support between GPRS Core and Inter AS Anchor
•
S5: user plane tunneling and tunnel management between Serving GW and PDN GW
•
S6: transfer of subscription and authentication data for user access to the evolved system
•
S7:Transfer of (QoS) policy and charging rules from PCRF
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 20
Chair Systems
www.tu-cottbus.de/systeme
The evolution of UTRAN
EPC and E-UTRAN (LTE)
UTRAN (UMTS)
GGSN
EPC
MME / S-GW / P-GW
MME / S-GW / P-GW
SGSN
S1
S1
RNC
S1
S1
RNC
X2
eNB
X2
NB
NB
NB
E-UTRAN
X2
eNB
NB
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
eNB
Page 21
Chair Systems
www.tu-cottbus.de/systeme
System architecture of LTE-Rel8
(source: TR 36.300)
•
eNB provides E-UTRA
U-Plane and C-Plane
protocol terminations
towards the UE
•
X2 connects eNBs as
mesh network, enabling
direct communication
between the elements
and eliminating the need
to tunnel data back and
forth through a (RNC)
•
S1 connects E-UTRAN
to EPC (eNBs are
connected to MME and
S-GW elements through
a “many-to-many”
relationship)
EPC
MME / S-GW / P-GW
MME / S-GW / P-GW
S1
S1
S1
S1
X2
eNB
X2
E-UTRAN
eNB
X2
eNB
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 22
Chair Systems
www.tu-cottbus.de/systeme
Overview of the functional split
(source: TR 36.300)
Inter cell RRM
•
Yellow boxes depict
the logical nodes
•
white boxes depict
the functional entities
of the control plane
•
blue boxes depict
the radio protocol
layers
RB control
Connection mobility cont.
Radio admission control
eNB measurement
configuration & provision
MME
NAS security
Dynamic resource
allocation (schedule)
Idle state mobility
handling
RRC
SAE bearer control
PDCP
RLC
Serving gateway
MAC
PHY
S1
Mobility
anchoring
PND Gateway
UE IP address allocation
Packet filtering
internet
E-UTRAN
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
EPC
Page 23
Chair Systems
www.tu-cottbus.de/systeme
Functions of the eNodeB
(source: TR 36.300)
•
•
•
•
•
Radio resource management
IP header compression and encryption
Selection of MME at UE attachment
Routing of user plane data towards S-GW
Scheduling and transmission of paging messages and broadcast
information
• Measurement and measurement reporting configuration for mobility
and scheduling
• Scheduling and transmission of ETWS messages
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 24
Chair Systems
www.tu-cottbus.de/systeme
Functions of the MME
(source: TR 36.300)
•
•
•
•
•
•
•
•
•
•
•
•
Non-access stratum (NAS) signaling and NAS signaling security
Access stratum (AS) security control
Inter CN node signalling for mobility between 3GPP access networks
Idle mode UE Reachability
Tracking Area list management (for UE in idle and active mode)
PDN GW and Serving GW selection
MME selection for handovers with MME change
SGSN selection for handovers to 2G or 3G 3GPP access networks
Roaming
Authentication
Bearer management functions including dedicated bearer establishment
Support for ETWS message transmission
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 25
Chair Systems
www.tu-cottbus.de/systeme
Functions of the S-GW
(source: TR 36.300)
• Local mobility anchor point for inter eNB handovers
• Mobility anchoring for inter 3GPP mobility
• E-UTRAN idle mode DL packet buffering and initiation of network
triggered service request procedure
• Lawful interception
• Packet routing and forwarding
• Transport level packet marking in the uplink and the downlink
• Accounting on user and QCI granularity for inter-operator charging
• UL and DL charging per UE, PDN and QCI
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 26
Chair Systems
www.tu-cottbus.de/systeme
Functions of the P-GW
(source: TR 36.300)
•
•
•
•
•
•
Per-user-based packet filtering
Lawful interception
UE IP address allocation
Transport level packet marking in the downlink
UL and DL service level charging, ating and rate enforcement
DL rate enforcement based on APN-AMBR
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 27
Chair Systems
www.tu-cottbus.de/systeme
Erweiterungen an dieser Stelle für
das nächste Semester
• Protocol Stack
– C-Plane
– U-Plane
• Attach Procedure
• Detach Procedure
• Mobile Terminating Call
• Mobile Originating Call
• Handover
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 28
Chair Systems
www.tu-cottbus.de/systeme
Identities of the UE
• International Mobile Subscriber Identity (IMSI)
– unique permanent identity of the SIM card, stored in HSS
– used as little as possible when UE is communicating with the network
• Temporary Mobile Subscriber Identity (TMSI)
– Alias used instead of IMSI
– temporary ID, allocated by the MME during the attach procedure
• Radio Network Temporary ID (RNTI)
– To identify the UE on the radio
– Handed out by eNodeB, when UE establishes radio contact with eNodeB
• Access Point Name (APN)
– IP address, allocated by PDN-Gateway as soon as UE is powered on
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 29
Chair Systems
www.tu-cottbus.de/systeme
Attach procedure
MME
HSS
2.
UE
Internet
3.
1.
eNodeB
4.
S-GW
1.
2.
3.
4.
PDN-GW
UE contacts eNB it hears the strongest
eNB will then select an MME for the UE
MME will select a serving gateway
S-GW selects a PDN-GW which provides an IP to the UE (PDN-GW is
selected from the APN parameter provided by the enduser or the operator)
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 30
Chair Systems
www.tu-cottbus.de/systeme
LTE enabling technologies
•
•
•
•
Orthogonal Frequency Division Multiple Access (OFDMA)
Single Carrier FDMA (SC-FDMA)
Multiple Input Multiple Output (MIMO)
…
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 31
Chair Systems
www.tu-cottbus.de/systeme
OFDM
Single carrier
• Available spectrum is divided into multiple
narrowband parallel channels (subcarriers)
f
W
• Information is transmitted on the subcarriers
at a reduced signal rate
Multi carrier
• Frequency responses of the subcarriers are
overlapping and orthogonal
f
W/N
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 32
Chair Systems
www.tu-cottbus.de/systeme
OFDM
(source: F. Khan, LTE for 4G Mobile Broadband, ISBN 978-0-521-88221-7)
• Example shows 5 OFDM subcarriers
– Each subcarrier is modulated by a data
symbol
– The OFDM symbol is formed by adding
the modulated subcarrier signals
– Here all subcarriers are modulated by
data symbols 1‘s
+
• Resulting OFDM symbol signal has
much larger signal amplitutde
variations than the individual
subcarriers
– This characteristic of OFDM signal
leads to larger signal peakness
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 33
Chair Systems
www.tu-cottbus.de/systeme
OFDM
(source: F. Khan, LTE for 4G Mobile Broadband, ISBN 978-0-521-88221-7)
• Application of rectangular pulse
in OFDM results in a sincsquare shape power spectral
density
• This allows minimal subcarrier
separation with overlapping
spectra where signal peak for a
given subcarrier corresponds to
spectrum nulls for the
remaining subcarriers
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 34
Chair Systems
www.tu-cottbus.de/systeme
Cyclic prefix
(source: F. Khan, LTE for 4G Mobile Broadband, ISBN 978-0-521-88221-7)
• Orthogonality of OFDM subcarriers
can be lost when the signal passes
through a time-dispersive radio
channel due to inter-OFDM symbol
interference (multipath propagation)
• A cyclic prefix extension of the OFDM
signal can be performed to avoid this
interference
• Cyclic prefix length is generally
chosen to accomodate the maximum
delay spread of the wireless channel
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 35
Chair Systems
www.tu-cottbus.de/systeme
OFDM signal representation
(source: TR 25.892)
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 36
Chair Systems
www.tu-cottbus.de/systeme
OFDMA
(source: http://cp.literature.agilent.com/litweb/pdf/5989-8139EN.pdf)
• Orthogonal Frequency Division Multiple Access (OFDMA) is a DL
multi carrier transmission scheme for E-UTRA FDD and TDD modes
based on conventional OFDM
• Incorporates elements of time division multiple access (TDMA) to
avoid narrowband fading and interference
• OFDMA allows subsets of the subcarriers to be allocated
dynamically among the different users on the channel
(Frequency selective scheduling)
• Result is a more robust system with increased capacity
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 37
Chair Systems
www.tu-cottbus.de/systeme
OFDM vs. OFDMA
• Data is modulated over sub-carriers and time slots
 Enables high data rate in a wireless channel
• Each subscriber can get different quantity of data
 Enables optimal balance of data forwarding between subscribers
OFDM
OFDMA
user 3
subcarriers
user 2
subcarriers
user 1
symbols (time)
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
symbols (time)
Page 38
Chair Systems
www.tu-cottbus.de/systeme
SC-FDMA
(source: http://cp.literature.agilent.com/litweb/pdf/5989-8139EN.pdf)
• Single Carrier – Frequency Division Multiple Access (SC-FDMA) is
UL transmission scheme for LTE with structure and performance
similar to OFDMA
• It combines the low Peak-to-Average Ratio (PAR) techniques of
single-carrier transmission systems (GSM and CDMA), with the
multi-path resistance and flexible frequency allocation of OFDMA
• Brief description:
– Convert data symbols from time to frequency domain via DFT
– Map data symbols to desired location in overall channel bandwidth
before they are converted back to time domain via IFFT
– Inserted cyclic prefix
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 39
Chair Systems
www.tu-cottbus.de/systeme
OFDMA vs. SC-FDMA
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 40
Chair Systems
www.tu-cottbus.de/systeme
SC-FDMA signal generation
(source: http://cp.literature.agilent.com/litweb/pdf/5989-8139EN.pdf)
• Create time domain waveform (IQ representation) of SC-FDMA symbol
• Represent the symbol in frequency domain via DFT
– DFT sampling frequency is chosen such that the time-domain waveform of
one SC-FDMA symbol is fully represented by M=4 DFT bins spaced 15 kHz
apart, with each bin representing one subcarrier in which amplitude and
phase are held constant for 66.7 μs
• Shift the symbol to the desired part of the overall channel bandwidth
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 41
Chair Systems
www.tu-cottbus.de/systeme
MIMO
(source: http://www.cs.wustl.edu/~jain/cse574-08/ftp/lte/index.html)
• Multiple antenna schemes that help to achieve higher spectral
efficiency (throughput ) and link reliability (data quality)
• Key idea: Tx sends multiple data streams on multiple antennas
and each stream goes through different paths to reach each Rx
antenna
• The different paths taken by the same stream to reach multiple Rx
allow canceling errors using superior signal processing techniques
• MIMO also achieves spatial multiplexing to distinguish among
different symbols on the same frequency
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 42
Chair Systems
www.tu-cottbus.de/systeme
MIMO formats
• Multipath propagation causes destructive interference (fading)
– Affects SNR and error rate of the channel
• MIMO utilizes the different paths to improve
– the robustness of the channel
• use multiple antennas to send the same signal on different paths
• signals on the different paths will be affected in different ways
• probability that all signals will be affected simultaneously is reduced
– the throughput
• use the additional paths as additional channels for data transmission
• Use spatial (antenna) diversity to transmit high quality data
• Use spatial multiplexing to transmit many data
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 43
Chair Systems
www.tu-cottbus.de/systeme
The different antenna schemes
(source: www.radio-electronics.com)
• SISO – Single Input Single Output
– No diversity, no additional processing
– (+) simple, (-) channel performance is limited, (-) impact
of interference and fading is significant
Tx
Rx
• SIMO – Single Input Multiple Output
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 44
...
– Receive diversity (smart antennas)
– Types: switched diversity and maximum ratio combining
– (+) simple implementation, (+) reduces effects of fading,
(-) processing needs to be done in Tx and Rx
Tx
Rx
Chair Systems
www.tu-cottbus.de/systeme
The different antenna schemes
(source: www.radio-electronics.com)
• MISO
...
– Transmission diversity
– Rx can receive optimum signal
– (+) multiple antennas and redundancy coding /
processing is moved from Rx to Tx, (+) size, cost and
battery consumption of the UE
Tx
Rx
• Full MIMO
Page 45
Tx
...
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
...
– more than one antenna on both sides (Tx and Rx)
– Channel coding to separate data from different paths
– (+) can improve robustness and throughput of the
channel, (-) additional cost for processing and antennas
Rx
Chair Systems
www.tu-cottbus.de/systeme
Shannon‘s Law
(source: www.radio-electronics.com)
• MIMO spatial multiplexing provides additional data capacity
• Achieved by using multiple paths as additional data channels
• Shannon’s Law defines maximum data rate on a radio channel
received signal power
[W] or [V]
 S
C B log 21 
 N
channel capacity [bps]
bandwidth [Hz]
noise over the bandwidth
[W] or [V]
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 46
Chair Systems
www.tu-cottbus.de/systeme
MIMO spatial multiplexing
(source: www.radio-electronics.com)
• MIMO systems utilize a matrix mathematical approach
h11
...
1
t1
h21
t2
...
...
hnn
...
MIMO Channel
...
data streams to transmit
2
...
n
t1
MIMO-Rx
processing
2
...
...
tn
MIMO-Tx
processing
t2
1
n
tn
received data streams
• Transmit a number of n data streams t from n antennas
• Each path has different channel properties h
• Properties are processed to enable Rx to be able to differentiate
between the different data streams
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 47
Chair Systems
www.tu-cottbus.de/systeme
MIMO spatial multiplexing
(source: www.radio-electronics.com)
...
r1 = h11t1 + h12t2 + … + h1ntn
...
r2 = h21t1 + h22t2 + … + h2ntn
[R] = [H] x [T]
...
...
rn = hn1t1 + hn2t2 + … + hnntn
...
• rn is the signal received at antenna n
• To recover transmitted data stream tn
– Estimate individual channel transfer characteristic hij to determine
the channel transfer matrix [H]
– Multiply received vector with inverse of the transfer matrix [H]
[T] = [H]-1 x [R]
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 48
Chair Systems
www.tu-cottbus.de/systeme
Enabling Technologies for LTEAdvanced
•
Peak Data Rate improvement
– DL 4x4 : LTE baseline 2x2
– UL 2x4 : LTE baseline 1x2
– 8 Tx antennas at eNode-B including 8x8 MIMO spatial multiplexing is
also considered
•
Sector/cell throughput improvement
– Advanced Downlink MU-MIMO: 8 Tx beam-forming
– Uplink SU-MIMO
– Hybrid OFDMA and SC-FDMA in uplink
– Multi-stream MIMO SFN broadcast
– Superposition of unicast and broadcast traffic
•
Cell edge performance improvement
– Multi-hop relay – coverage extension
– Multi-cell MIMO (Network MIMO) – toward a cell without cell edge?
Monday, 11 April 2016
winter term 2010/11 – Mobile Communication Systems II
Page 49
Chair Systems
www.tu-cottbus.de/systeme