Transcript mslab.kaist.ac.kr

Our G-enealogy
Brough Turner
Founder & CTO
Ashtonbrooke.com
[email protected]
http://blogs.broughturner.com
Original slides: http://images.tmcnet.com/expo/west-09/presentations/4g3-01-turner-ashtonbrook.ppt
Our G-enealogy
How the history of cellular technology helps us
understand 4G technology and business models
and their likely impact on wireless broadband
• Brief history of cellular wireless telephony
– Radio technology: TDMA, CDMA, OFDMA
– Mobile core network architectures
• Demographics & market trends today
– 3.5G, WiMAX, LTE & 4G migration paths
• Implications for the next 2-5 years
2
Mobiles overtake fixed
Source: ITU World ICT Indicators, June 2008
3
Mobile Generations
G
Data Rates
1
Analog
Typical 2.4 Kbps; max 22 Kbps
2
Digital – TDMA, CDMA
9.6 - 14.4 Kbps (circuit data)
2.5
GPRS – mux packets in
voice timeslots
15 - 40 Kbps
Improved modulation,
using CDMA variants
50 – 144 Kbps (1xRTT);
200 – 384 Kbps (UMTS);
500 Kbps – 2.4 Mbps (EVDO)
More modulation tweaks
2–14 Mbps (HSPA), then 28 Mbps
& 42/84 Mbps future evolution
New modulation (OFDMA);
Multi-path (MIMO); All IP
LTE: potentially >100 Mbps with
adequate spectrum (20 MHz)
3
3.5
4
4
Summary
First Mobile Radio Telephone,
1924
Courtesy of Rich Howard
5
Cellular Mobile Telephony

Antenna diversity

Cellular concept
2
● Bell Labs (1957 & 1960)

Frequency reuse
● typically every 7 cells


Handoff as caller moves
Modified CO switch
● HLR, paging, handoffs

Sectors improve reuse
● every 3 cells possible
6
5
3
1
2
1
7
2
5
1
6
4
7
5
3
2
2
3
6
4
7
3
6
1
4
7
5
First Generation (nearly all
retired)
• Advanced Mobile Phone Service (AMPS)
– US trials 1978; deployed in Japan (’79) & US (’83)
– 800 MHz; two 20 MHz bands; TIA-553
• Nordic Mobile Telephony (NMT)
– Sweden, Norway, Demark & Finland
– Launched 1981
– 450 MHz; later at 900 MHz (NMT900)
• Total Access Communications System (TACS)
– British design; similar to AMPS; deployed 1985
7
2nd Generation – digital systems
• Leverage technology to increase capacity
– Speech compression; digital signal processing
• Utilize/extend “Intelligent Network” concepts
– Improve fraud prevention; Add new services
• Wide diversity of 2G systems
–
–
–
–
8
IS-54/ IS-136 Digital AMPS; PDC (Japan)
DECT and PHS; iDEN
IS-95 CDMA (cdmaOne)
GSM
2G “CDMA” (cdmaOne)
• Code Division Multiple Access
– all users share same frequency band
– discussed in detail later as CDMA is basis for 3G
• Qualcomm demo in 1989
– claimed improved capacity & simplified planning
• First deployment in Hong Kong late 1994
• Major success in Korea (1M subs by 1996)
• Adopted by Verizon and Sprint in US
• Easy migration to 3G (same modulation)
9
GSM – Global System for Mobile
• Originally “Groupe Spécial Mobile ”
– joint European effort beginning 1982
– Focus: seamless roaming all Europe
• Services launched 1991
– time division multiple access (8 users per 200KHz)
– 900 MHz band; later 1800 MHz; then 850/1900 MHz
• GSM – dominant world standard today
– well defined interfaces; many competitors; lowest
cost to deploy
– network effect took hold in late 1990s
10
GSM Dominant Today
• GSM+3GSM used by 88% of subscribers worldwide
• Asia leads with 42% of all mobile subscriptions
– AT&T and T-Mobile use GSM/3GSM in US today
GSM Subscribers
Source: Wireless Intelligence / GSM Association
11
GSM substantially enhanced
Widely deployed  significant payback for enhancements
• HSCSD - high speed circuit-switched data
• GPRS - general packet radio service
• Synchronization between cells
– Minimize interference; help fix mobile’s location
• AMR vocoder – increase capacity (& fidelity)
• Frequency hopping (to overcome fading)
• Discontinuous transmission (more calls/ cell)
• Cell overlays with reuse partitioning
12
Voice vs. Data
Voice
Data
Error
Less sensitive
Sensitive
Delay
Sensitive
Less sensitive
Energy
Low
High
Priority
High
Low
Max rate
Data
Data
Data
limit
Voice
Voice + Data System
(shared)
Voice
Separate system
(e.g., EVDO)
1G, 2G, 3G Multi-Access Technologies
Courtesy of Petri Possi, UMTS World
4G and future wireless systems optimize a
combination of frequency, time and coding
e.g. OFDMA & SC-FDMA (discussed later)
14
2G & 3G – Code Division Multiple
Access
• Spread spectrum modulation
– originally developed for the military
– resists jamming and many kinds of interference
– coded modulation hidden from those w/o the code
• All users share same (large) block of spectrum
– one for one frequency reuse
– soft handoffs possible
• All 3G radio standards based on CDMA
– CDMA2000, W-CDMA and TD-SCDMA
15
Courtesy of Suresh Goyal & Rich Howard
16
The 3G Vision
• Universal global roaming
– Sought 1 standard (not 7), (but got 3:
3GSM, CDMA 2000 & TD-SCDMA)
• Increased data rates
• Multimedia (voice, data & video)
• Increased capacity (more spectrally efficient)
• Data-centric architecture (ATM at first, later IP)
• But deployment took much longer than expected
– No killer data app; new spectrum costly; telecom bubble
burst; much of the vision was vendor-driven
17
3G Radio technology today
• CDMA 2000 – Multi Carrier CDMA
– Evolution of IS-95 CDMA; but now a dead end
• UMTS (W-CDMA, HSPA) – Direct Spread CDMA
– Defined by 3GPP Paired spectrum bands
• TD-SCDMA – Time Division Synchronous CDMA
– Defined by Chinese Academy of Telecommunications
Technology under the Ministry of Information Industry
Single spectral band with time division duplexing
18
Why CDMA 2000 lost out
• Had better migration story from 2G to 3G
– Evolution from original Qualcomm CDMA (IS-95)
– cdmaOne operators didn’t need additional spectrum
• Higher data rates than UMTS, at least at first
• Couldn’t compete with GSM’s critical mass
– Last straw when Verizon Wireless selected 3GPP’s
Long Term Evolution (LTE) for their 4G network
– Verizon selection 11/07
– Qualcomm abandons further development 11/08
19
3GPP (3rd Generation Partnership
Project)
Japan
USA
• Partnership of 6 regional standards groups, which
translate 3GPP specifications to regional standards
• Controls evolution of GSM, 3GSM (UMTS, WCDMA, HSPA) & LTE
20
UMTS (3GSM) is market leader
• GSM evolution: W-CDMA, HSDPA, HSPA, +…
– leverages GSM’s dominant position
• Legally mandated in Europe and elsewhere
• Requires substantial new spectrum
– 5 MHz each way (symmetric) at a minimum
• Slow start (was behind CDMA 2000), but now the
accepted leader
– Network effect built on GSM’s >80% market share
– Surely LTE will benefit in the same fashion…
21
TD-SCDMA
(Time division synchronous CDMA)
• Chinese development
– IPR bargaining tool with West? Late to market, but
big deployment plans
• Single spectral band
– unpaired spectrum; as little as 1.6 MHz; time
division duplex (TDD) with high spectral efficiency;
good match for asymmetrical traffic!
• Power amplifiers must be very linear
– relatively hard to meet specifications
22
China 3G
• Largest mobile market in world (630 M subs)
– Largest population in world (1.3 billion)
• Home-brew 3G standard: TD-SCDMA
– 3G licenses were delayed until TD-SCDMA worked
– 2008 trials: 10 cities, 15K BSs & 60K handsets
• 3G granted January 2009
– China Mobile: TD-SCDMA
– China Unicom: 3GSM (UMTS)
– China Telecom: CDMA 2000
23
3G Subscribers (2Q 2008)
• 18% on 3G; 82% on 2G; 0.01% on 1G
• EU & US 3G penetration approaching 30%
• US penetration rate soaring
3-month averages
ending June 2008
& June 2007
All mobile
subscribers
ages 13+
Source: comScore MobiLens
24
Diverse Mobile Wireless Spectrum
25
Wireless Migration
26
OFDM
→OFDMA MIMO
Wireless capacity / throughput
4G
LTE
3G
2G
UMTS/HSPA
CDMA
First cell
phones
GSM
AMPS
1970
27
WiMAX
Wi-Fi
1980
1990
2000
2010
ITU Framework
Pervasive connectivity
WLAN - WMAN - WWAN
ITU – United Nations
telecommunications standards
organization
Accepts detailed standards
contributions from 3GPP, IEEE
and other groups
28
3GPP – WWAN (wireless wide
area network)
IEEE 802.16 – WMAN (wireless
metropolitan area network)
IEEE 802.11 – WLAN (wireless
local area network)
ITU-R Mobile Telecommunications
• IMT-2000
– Global standard for third generation (3G) wireless
– Detailed specifications from 3GPP, 3GPP2, ETSI and others
• IMT-Advanced
– New communications framework: deployment ~2010 to 2015
– Data rates to reach around 100 Mbps for high mobility and
1 Gbps for nomadic networks (i.e. WLANs)
– High mobility case via either or both evolved LTE & WiMAX
– 802.11ac and 802.11ad
addressing the nomadic case
29
LTE highlights
• Sophisticated multiple access schemes
– DL: OFDMA with Cyclic Prefix (CP)
– UL: Single Carrier FDMA (SC-FDMA) with CP
• Adaptive modulation and coding
– QPSK, 16QAM, and 64QAM
– 1/3 coding rate, two 8-state constituent encoders,
and a contention-free internal interleaver
• Advanced MIMO spatial multiplexing
– (2 or 4) x (2 or 4) downlink and uplink
30
4G Technology – OFDMA
• Orthogonal Frequency Division Multiple Access
– Supercedes CDMA used in all 3G variants
• OFDMA = Orthogonal Frequency Division
Multiplexing (OFDM) plus statistical multiplexing
– Optimization of time, frequency & code multiplexing
• OFDM already deployed in 802.11a & 802.11g
– Took Wi-Fi from 11 Mbps to 54 Mbps & beyond
31
Orthogonal Frequency Division
Multiplexing
– Many closely-spaced sub-carriers, chosen to be orthogonal,
thus eliminating inter-carrier interference
– Varies bits per sub-carrier based on instantaneous received
power
32
Statistical Multiplexing
(in OFDMA)
• Dynamically allocate user data to sub-carriers based
on instantaneous data rates and varying sub-carrier
capacities
• Highly efficient use of spectrum
• Robust against fading, e.g. for mobile operation
33
FDMA vs. OFDMA
• OFDMA more frequency efficient
• Dynamically map traffic to frequencies
based on their instantaneous
throughput
Guard
band
Channel
FDMA
34
OFDMA
4G Technology - MIMO
35

Multiple Input Multiple Output smart antenna technology

Multiple paths improve link reliability and increase
spectral efficiency (bps per Hz), range and directionality
Municipal Multipath Environment
36
SDMA = Smart Antenna Technologies
• Beamforming
– Use multiple-antennas to
spatially shape the beam
• Spatial Multiplexing a.k.a.
Collaborative MIMO
– Multiple streams transmitted
– Multi-antenna receivers
separate the streams to
achieve higher throughput
– On uplink, multiple singleantenna stations can transmit
simultaneously
• Space-Time Codes
– Transmit diversity such as
Alamouti code reduces fading
37
2x2 Collaborative MIMO
give 2x peak data rate by
transmitting two data
streams
4G Technology – SC-FDMA
• Single carrier multiple access
– Used for LTE uplinks
– Being considered for 802.16m uplink
• Similar structure and performance to OFDMA
– Single carrier modulation with DFT-spread
orthogonal frequency multiplexing and FD
equalization
• Lower Peak to Average Power Ratio (PAPR)
– Improves cell-edge performance
– Transmit efficiency conserves handset battery life
38
Key Features of WiMAX and LTE
•
•
•
•
OFDMA (Orthogonal Frequency Division Multiple Access)
Users are allocated a slice in time and frequency
Flexible, dynamic per user resource allocation
Base station scheduler for uplink and downlink resource allocation
– Resource allocation information conveyed on a frame‐by frame basis
•
Support for TDD (time division duplex) and FDD (frequency division
duplex)
TDD: single frequency channel for uplink and downlink
DL
UL
DL
UL
39
FDD
Paired channels
3G/4G Comparison
Peak Data Rate (Mbps)
40
Access time
(msec)
Downlink
Uplink
HSPA (today)
14 Mbps
2 Mbps
50-250 msec
HSPA (Release 7) MIMO 2x2
28 Mbps
11.6 Mbps
50-250 msec
HSPA + (MIMO, 64QAM
Downlink)
42 Mbps
11.6 Mbps
50-250 msec
WiMAX Release 1.0 TDD (2:1
UL/DL ratio), 10 MHz channel
40 Mbps
10 Mbps
40 msec
LTE (Release 8), 5+5 MHz
channel
43.2 Mbps
21.6 Mbps
30 msec
WiMAX vs. LTE
• Commonalities
– IP-based
– OFDMA and MIMO
– Similar data rates and channel widths
• Differences
– Carriers are able to set requirements for LTE
through organizations like NGMN and LSTI, but
cannot do this as easily at the IEEE-based 802.16
– LTE backhaul is, at least partially, designed to
support legacy services while WiMAX assumes
greenfield deployments
41
Commercial Issues
LTE
• Deployments likely
slower than projected
• 2-3 year lead, likely
maintained for years
But
• Dedicated spectrum in
many countries
• Eventual migration path
for GSM/3GSM, i.e. for >
80% share
• Will be lowest cost &
dominant in 2020
42
WiMAX
But
• Likely < 15% share by
2020 & thus more costly
3G Partnership Project
Defines migration GSM to UMTS/ 3GSM to LTE
Release
Specs
complete
First
deployed Major new features defined
98
1998
99
1Q 2000
2003
W-CDMA air interface
4
2Q 2001
2004
Softswitching IP in core network
5
1Q 2002
2006
HSDPA & IP Multimedia System (IMS)
6
4Q 2004
2007
HSUPA, MBMS, GAN, PoC & WLAN integration
7
4Q 2007
future
HSPA+, Better latency & QoS for VoIP
8
4Q 2008 *
future
LTE, All-IP
Last purely 2G GSM release
W-CDMA – Wideband CDMA modulation
* Rush job?
HSxPA – High Speed (Download/Upload) Packet Access
MBMS – Multimedia Broadcast Multicast Service
GAN – Generic Access Network
PoC – Push-to-talk over Cellular
LTE – Long Term Evolution, a new air interface based on OFDM modulation
43
Core Network Architectures
• Two widely deployed architectures today
• 3GPP evolved from GSM-MAP
– Used by GSM & 3GSM operators (88% of subs globally)
– “Mobile Application Part” defines signaling for mobility,
authentication, etc.
• 3GPP2 evolved from ANSI-41 MAP
– ANSI-41 used with AMPS, TDMA & CDMA 2000
– GAIT (GSM ANSI Interoperability Team) allowed
interoperation, i.e., roaming
• Evolving to common “all IP” vision based on 3GPP
44
Typical 2G Mobile Architecture
PSDN
BSC
BTS
BSC
HLR
SMS-SC
PLMN
MSC/VLR
BSC
MSC/VLR
BSC
BTS Base Transceiver Station
BSC Base Station Controller
GMSC
Tandem
CO
Tandem
CO
CO
45
PSTN
MSC Mobile Switching Center
VLR Visitor Location Register
HLR Home Location Register
Separation of Signaling &
Transport
• Like PSTN, 2G mobile networks have one network
plane for voice circuits and another network plane for
signaling
• Some elements reside only in the signaling plane
– HLR, VLR, SMS Center, …
HLR
MSC
MSC
SMS-SC
VLR MSC
Signaling Plane (SS7)
Transport Plane (Voice)
46
Signaling in Core Network
• Based on SS7
– ISUP and specific Application Parts
• GSM MAP and ANSI-41 services
– mobility, call-handling, O&M, authentication,
supplementary services, SMS, …
• Location registers for mobility management
– HLR: home location register has permanent data
– VLR: visitor location register – local copy for
roamers
47
PSTN-to-Mobile Call
PLMN
PLMN
(Visitor)
(Home)
PSTN
(SCP) HLR
Signaling
over SS7
SCP
Where is the subscriber?
MAP/ IS41 (over TCAP)
(STP)
ISUP
4
Provide Roaming
2
3
5
Routing Info
VMSC
MS
BSS
(SSP)
6
IAM
1
GMSC
IAM
(STP)
(SSP)
VLR
514 581 ...
48
(SSP)
GSM 2G Architecture
NSS
BSS
E
Abis
PSTN
A
PSTN
B
BSC
MS
BTS
C
MSC
VLR
D
GMSC
SS7
H
HLR
BSS Base Station System
NSS Network Sub-System
BTS Base Transceiver Station
MSC Mobile-service Switching Controller
BSC Base Station Controller
VLR Visitor Location Register
MS Mobile Station
HLR Home Location Register
AuC Authentication Server
GMSC Gateway MSC
49
AuC
GSM Global System for Mobile communication
2.5G Architectural Detail
2G MS (voice only)
NSS
BSS
E
Abis
PSTN
A
PSTN
B
BSC
MS
C
MSC
BTS
Gs
GMSC
D
VLR
SS7
H
Gb
2G+ MS (voice&data)
Gr
HLR
AuC
Gc
Gn
SGSN
IP
PSDN
GGSN
BSS Base Station System
NSS Network Sub-System
SGSN Serving GPRS Support Node
BTS Base Transceiver Station
MSC Mobile-service Switching Controller
GGSN Gateway GPRS Support Node
BSC Base Station Controller
VLR Visitor Location Register
HLR Home Location Register
AuC Authentication Server
50
Gi
GMSC Gateway MSC
GPRS General Packet Radio Service
3G rel99 Architecture (UMTS)
2G MS (voice only)
CN
BSS
E
Abis
PSTN
A
PSTN
B
BSC
Gb
BTS
C
MSC
Gs
GMSC
D
VLR
SS7
H
2G+ MS (voice & data)
IuCS
RNS
Gr
HLR
ATM
Iub
IuPS
RNC
AuC
Gc
Gn
SGSN
Gi
IP
PSDN
GGSN
Node B
3G UE (voice & data)
BSS Base Station System
CN Core Network
SGSN Serving GPRS Support Node
BTS Base Transceiver Station
MSC Mobile-service Switching Controller
GGSN Gateway GPRS Support Node
BSC Base Station Controller
VLR Visitor Location Register
HLR Home Location Register
RNS Radio Network System
RNC Radio Network Controller
51
AuC Authentication Server
GMSC Gateway MSC
UMTS Universal Mobile Telecommunication System
3GPP rel5 ― IP Multimedia
2G MS (voice only)
CN
CS-MGW
A/IuCS
Abis
Nc
Mc
BSC
Gb/IuPS
BTS
2G+ MS (voice & data)
IuCS
C
VLR
GMSC server
D
SS7
H
ATM
Gr
IuPS
HSS
AuC
IP/ATM
Gc
Gn
Gi
SGSN
GGSN
Node B
3G UE (voice & data)
IM-MGW
IM
Gs
IM IP Multimedia sub-system
PSTN
MRF Media Resource Function
IP
CSCF Call State Control Function
Mg
MGCF Media Gateway Control Function (Mc=H248,Mg=SIP)
MRF
Mc
MGCF
IM-MGW IP Multimedia-MGW
CSCF
52
PSTN
B
RNS
RNC
PSTN
Mc
MSC Server
Gs
Iub
CS-MGW
Nb
BSS
IP Network
3GPP2 Defines IS-41 Evolution
• 3rd Generation Partnership Project “Two”
– Evolution of IS-41 to “all IP” more direct (skips ATM
stage), but not any faster
– Goal of ultimate merger (3GPP + 3GPP2) remains
•
•
•
•
•
53
1xRTT – IP packets (like GPRS)
1xEVDO – Evolution data-optimized
1xEVDV – abandoned
3x – Triples radio data rates
Universal Mobile Broadband (UMB) –
abandoned
LTE and IMS
• LTE is an all-IP network
– Not compatible with legacy voice services
– Assumes the use of IP Multimedia System (IMS)
• Initial LTE networks will be data only
• Initial LTE handsets will be
multi-modal, supporting HSPA and
earlier systems for voice telephony
• VOLGA Forum working on a fix
– Voice over LTE via Generic Access
54
LTE’s System Architecture Evolution
(SAE)
RAN (Radio access network)
SGSN (Serving GPRS Support Node)
PCRF (policy and charging function)
HSS (Home Subscriber Server)
MME (Mobility Management Entity)
SAE (System Architecture Evolution)
55
Diagram by Huawei
Mobile Service Revenues
• > $800 billion in 2007, growing 6%-7% per year
– > $1 trillion by 2012
• Voice services dominate: 81%
• SMS services: 9.5% ; All other non-voice services: 9.5%
Source: Portio Research
56
Mobile Services Futures
• Affordable open mobile Internet access coming
– Five competing 3.5G operators in US by 2010
– Smart phone penetration soaring
• Operators’ control of handset software slipping
– iPhone and Android application stores, initiatives for
Symbian, WinMobile, Adobe AIR, etc.
• The Internet is the killer platform
– Mobile Internet access driving 3G data usage
57