Transcript L13_Cellular_Tutorialx

Our G-enealogy
Original Slides from
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
• 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
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
First two-way, voice-based radio telephone
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
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
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)
13
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
• All 3G radio standards based on CDMA
– CDMA2000, W-CDMA and TD-SCDMA
14
Courtesy of Suresh Goyal & Rich Howard
15
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
16
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
– Asynchronous CDMA
• 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
17
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 11/2007
– Qualcomm abandons further development 11/2008
18
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
19
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…
20
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
• Power amplifiers must be very linear
– relatively hard to meet specifications
21
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
22
3G Subscribers (Q4 2011)
23
http://kpcb.com/insights/2012-internet-trends
Diverse Mobile Wireless Spectrum
24
Wireless Migration
25
Wireless Subscribers in Korea
2012.2
Changes
+/+/- %
2012.3
방송통신위원회
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
– DownLink: OFDMA with Cyclic Prefix (CP)
– UpLink: 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
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 Architecture
• 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
Core Network Architecture
45
Summary
• Brief history of cellular wireless telephony
– Radio technology: TDMA, CDMA, OFDMA
– Mobile core network architecture
46