Founder & CTO
Ashtonbrooke.com
broughturner@gmail.com
http://blogs.broughturner.com
Original slides: http://images.tmcnet.com/expo/west-09/presentations/4g3-01-turner-ashtonbrook.ppt

2
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

3
Source: ITU World ICT Indicators, June 2008

4
G
Summary
1 Analog
2 Digital – TDMA, CDMA
2.5
GPRS – mux packets in voice timeslots
Data Rates
Typical 2.4 Kbps; max 22 Kbps
9.6 - 14.4 Kbps (circuit data)
15 - 40 Kbps
3
4
Improved modulation, using CDMA variants
3.5
More modulation tweaks
New modulation (OFDMA);
Multi-path (MIMO); All IP
50 – 144 Kbps (1xRTT);
200 – 384 Kbps (UMTS);
500 Kbps – 2.4 Mbps (EVDO)
2 –14 Mbps (HSPA), then 28 Mbps
& 42/84 Mbps future evolution
LTE: potentially >100 Mbps with adequate spectrum (20 MHz)

5
Courtesy of Rich Howard

6
 Antenna diversity
 Cellular concept
● 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
1
2
2
3
4
5
3
1
2
4
5
6
7
7
5
6
7
1
2
3
4
5
1
2
6
7
3

7
• 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

8
• 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
– IS-54/ IS-136 Digital AMPS; PDC (Japan)
– DECT and PHS; iDEN
– IS-95 CDMA (cdmaOne)
– GSM

9
• 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)

10
• 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

11
• 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

12
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

Max rate
Error
Delay
Energy
Priority
Voice
Less sensitive
Sensitive
Low
High
Data
Sensitive
Less sensitive
High
Low
Voice
Data
Data limit
Voice
Data
Voice + Data System
(shared)
Separate system
(e.g., EVDO)

14
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)

15
• 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

16
Courtesy of Suresh Goyal & Rich Howard

17
• 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

18
– 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

19
• 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

Japan
USA
20
• Partnership of 6 regional standards groups, which translate 3GPP specifications to regional standards
• Controls evolution of GSM, 3GSM
(UMTS, WCDMA, HSPA) & LTE

21
• 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…

22
• 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

23
• 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

24
• 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

25

26

27
1970
First cell phones
AMPS
2G
OFDM
→
OFDMA MIMO
3G
4G
Wi-Fi
WiMAX
LTE
UMTS/HSPA
GSM
CDMA
1980 1990 2000 2010

ITU Framework
28
Pervasive connectivity
WLAN - WMAN - WWAN
ITU – United Nations telecommunications standards organization
Accepts detailed standards contributions from 3GPP, IEEE and other groups
3GPP – WWAN (wireless wide area network)
IEEE 802.16
– WMAN (wireless metropolitan area network)
IEEE 802.11
– WLAN (wireless local area network)

29
• 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

30
• 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

31
• 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

32
– Many closely-spaced sub-carriers, chosen to be orthogonal, thus eliminating inter-carrier interference
– Varies bits per sub-carrier based on instantaneous received power

33
• 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

34
• OFDMA more frequency efficient
• Dynamically map traffic to frequencies based on their instantaneous throughput
Guard band
Channel
FDMA OFDMA

35
 Multiple Input Multiple Output smart antenna technology
 Multiple paths improve link reliability and increase spectral efficiency (bps per Hz), range and directionality

36

37
• 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
2x2 Collaborative MIMO give 2x peak data rate by transmitting two data streams

38
• 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

39
• 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
FDD
Paired channels

40
HSPA (today)
HSPA (Release 7) MIMO 2x2
HSPA + (MIMO, 64QAM
Downlink)
WiMAX Release 1.0 TDD (2:1
UL/DL ratio), 10 MHz channel
LTE (Release 8), 5+5 MHz channel
Peak Data Rate (Mbps)
Downlink Uplink
14 Mbps
28 Mbps
42 Mbps
2 Mbps
11.6 Mbps
11.6 Mbps
40 Mbps
43.2 Mbps
10 Mbps
21.6 Mbps
Access time
(msec)
50-250 msec
50-250 msec
50-250 msec
40 msec
30 msec

41
• 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

42
LTE
• Deployments likely slower than projected
But
• Eventual migration path for GSM/3GSM, i.e. for >
80% share
• Will be lowest cost & dominant in 2020
WiMAX
• 2-3 year lead, likely maintained for years
• Dedicated spectrum in many countries
But
• Likely < 15% share by
2020 & thus more costly

43
Release
98
99
4
5
6
7
8
Defines migration GSM to UMTS/ 3GSM to LTE
Specs complete
1998
1Q 2000
2Q 2001
1Q 2002
4Q 2004
4Q 2007
4Q 2008 *
First deployed Major new features defined
Last purely 2G GSM release
2003 W-CDMA air interface
2004 Softswitching IP in core network
2006 HSDPA & IP Multimedia System (IMS)
2007 HSUPA, MBMS, GAN, PoC & WLAN integration future HSPA+, Better latency & QoS for VoIP future LTE, All-IP
W-CDMA
– Wideband CDMA modulation
HSxPA – High Speed (Download/Upload) Packet Access
MBMS
– Multimedia Broadcast Multicast Service
GAN – Generic Access Network
*
Rush job?
PoC – Push-to-talk over Cellular
LTE
– Long Term Evolution, a new air interface based on OFDM modulation

44
• 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

45
CO
BTS
BSC
BSC
MSC/VLR
CO
Tandem
PSDN
BSC
HLR
PLMN
SMS-SC
MSC/VLR
BSC
BTS Base Transceiver Station
BSC Base Station Controller
GMSC
PSTN
Tandem
CO
MSC Mobile Switching Center
VLR Visitor Location Register
HLR Home Location Register

46
• 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, …
MSC
MSC
HLR SMS-SC
VLR MSC
Signaling Plane (SS7)
Transport Plane (Voice)

47
• 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

48
PLMN
(Visitor)
PLMN
(Home)
(SCP) HLR
Signaling over SS7
MAP/ IS41 (over TCAP)
ISUP
(STP)
4
Provide Roaming
MS
VMSC
BSS
VLR
(SSP)
Where is the subscriber?
3
5
Routing Info
6
IAM
2
GMSC
(SSP)
514 581 ...
SCP
1
PSTN
(SSP)

49
MS
BTS
Abis
BSS
BSC
BSS Base Station System
BTS Base Transceiver Station
BSC Base Station Controller
MS Mobile Station
A
NSS
E
MSC
B
VLR
D
HLR
H
C
GMSC
SS7
AuC
PSTN
PSTN
NSS Network Sub-System
MSC Mobile-service Switching Controller
VLR Visitor Location Register
HLR Home Location Register
AuC Authentication Server
GMSC Gateway MSC
GSM Global System for Mobile communication

2G MS (voice only)
Abis
BSS
BSC
MS
BTS
2G+ MS (voice&data)
50
BSS Base Station System
BTS Base Transceiver Station
BSC Base Station Controller
A
Gb
NSS
E
B
MSC
Gs
VLR
D
SGSN
C
GMSC
SS7
H
Gr HLR
Gn
AuC
Gc
IP
GGSN
PSTN
Gi
PSTN
PSDN
NSS Network Sub-System
MSC Mobile-service Switching Controller
VLR Visitor Location Register
HLR Home Location Register
AuC Authentication Server
GMSC Gateway MSC
SGSN Serving GPRS Support Node
GGSN Gateway GPRS Support Node
GPRS General Packet Radio Service

2G MS (voice only)
Abis
BSS
CN
PSTN
A
E PSTN
BTS
2G+ MS (voice & data)
BSC
Gb
B
MSC
Gs
VLR
D
H
C
GMSC
SS7
IuCS
RNS
Gr HLR
AuC
Gc
Iub
ATM
IuPS
Gn Gi
PSDN
RNC
Node B
3G UE (voice & data)
BSS Base Station System
BTS Base Transceiver Station
BSC Base Station Controller
RNS Radio Network System
RNC Radio Network Controller
51
SGSN
IP
GGSN
CN Core Network
MSC Mobile-service Switching Controller
VLR Visitor Location Register
HLR Home Location Register
SGSN Serving GPRS Support Node
GGSN Gateway GPRS Support Node
UMTS Universal Mobile Telecommunication System
AuC Authentication Server
GMSC Gateway MSC

2G MS (voice only)
Abis
BSS
BTS
2G+ MS (voice & data)
Iub
BSC
RNS
CN
Nb
A/IuCS
CS-MGW
Mc
B
Gb/IuPS
IuCS
ATM
MSC Server
Gs
VLR
D
Gr
IuPS
Nc
HSS
Gn
H
C
AuC
Gc
IP/ATM
CS-MGW
Mc
PSTN
SS7
GMSC server
Gi
RNC
SGSN
Node B
3G UE (voice & data)
IM IP Multimedia sub-system
MRF Media Resource Function
CSCF Call State Control Function
MGCF Media Gateway Control Function (Mc=H248,Mg=SIP)
IM-MGW IP Multimedia-MGW
52
IM
MRF
Gs
CSCF
GGSN
IP
Mg
Mc
MGCF
IM-MGW
PSTN
PSTN
IP Network

53
• 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
• 1xRTT – IP packets (like GPRS)
• 1xEVDO – Evolution data-optimized
• 1xEVDV – abandoned
• 3x – Triples radio data rates
• Universal Mobile Broadband (UMB) – abandoned

54
• 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

55
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)
Diagram by Huawei

56
• > $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

57
• 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