CW Wireless Heritage SIG
‘Liberating the laptop: an overview of
cellular data communications'
Andy Sutton
Visiting Professor
Department of Computing, Science and Engineering
Thursday 27th November 2014
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Contents
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Cellular mobile communications - the
mobile telephone - voice…
•
Nomadic working, pre-mobile
•
GSM - clear digital voice,
international roaming and the
introduction of SMS
•
GSM circuit switched data
•
GPRS – introducing IP packet to
cellular networks
•
UMTS, data built in..
•
High speed packet data – HSDPA
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Summary
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Cellular mobile
communications - the mobile
telephone - voice…
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Analogue cellular
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A typical analogue FM TACS/ETACS mobile phone had just a few kilobytes
of memory
•
Every phone took 8 hours to complete RF testing
Motorola 8500X - 1983
Nokia-Mobira Cityman 1320 - 1987
Motorola 7600X - 1994
Source: http://www.cntr.salford.ac.uk/comms/etacs_mobiles.php
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Laptop computers
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Source: http://oldcomputers.net
PCMCIA…
•
•
•
•
The PCMCIA (Personal Computer Memory Card International Association)
industry organisation was based on the original initiative of the British
mathematician and computer scientist Ian Cullimore
Ian was one of the founders of the Sunnyvale-based Poqet Computer Corporation,
who was seeking to integrate some kind of memory card technology as storage
medium into their early DOS-based palmtop PCs, when traditional floppy drives
and hard-disks were found to be too power-hungry and large to fit into their
battery-powered handheld devices.
In July 1989 Poqet contacted Fujitsu for their existing but still non-standardised
SRAM memory cards, and Intel for their flash technology, the necessity and
potential of establishing a worldwide memory card standard became obvious to
the parties involved
This led to the foundation of the PCMCIA organisation in September 1989
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Source: http://en.wikipedia.org/wiki/PC_Card
Nomadic working
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1, GSM - clear digital voice,
international roaming and
the introduction of SMS
2, GSM circuit switched data
3, GPRS - introducing IP
packet to cellular networks
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Early GSM phones
Nokia 1011
Orbitel 901
Nokia’s
first
venture
into the
GSM
market
they
came to
dominate
Source: http://www.gsmhistory.com/vintage-mobiles/
Motorola
International 3200
The first GSM
mobile handportable phone
DCS1800 (later GSM1800)
Nokia 2140
Siemens m200 & Motorola m300
Motorola mr1
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Nokia dominated the GSM
market
Nokia 1011
Nokia 2140
Nokia 3210e Nokia 6230i
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GSM with Circuit Switched
data
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Data over GSM
•
•
•
•
•
When first considered it was assumed that the vast majority of GSM data
users would wish to communicate with a host on the PSTN
Therefore, an audio modem must appear somewhere in the GSM
network to ensure data is sent in the correct 3.1kHz audio format
With TACS data implementations it was possible to place the modem at
the mobile side, however this is not possible with GSM as the modem
tones would be corrupted if passed through the voice codec
So, to send data over the Um interface it is necessary for it to remain in a
digital format
The solution is to place the audio modem at the gateway between the
GSM PLMN and the PSTN known as the Inter-Working Function (IWF)
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Data over GSM
BSC
TRAU
MSC
IWF
PSTN
PLMN
ISDN
Internet
Etc.
BTS
• Available GSM CS user data rates are:
– 300bps, 600bps, 1.2kbps, 4.8kbps & 9.6kbps
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Data over GSM
BSC
TRAU
MSC
PSTN
PLMN
ISDN
Internet
Etc.
IWF
BTS
9.6kbps
12kbps
16kbps
16kbps
64kbps
64kbps
9.6kbps
• Available GSM CS user data rates are:
– 300bps, 600bps, 1.2kbps, 4.8kbps & 9.6kbps
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An interface between the
mobile phone and laptop…
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14k4 & HSCSD
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•
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•
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GSM Phase 2+
An improved C/I ratio is required for 14k4 data as
less error correction is applied
A multi-frame structure is required to transfer status
and control information due to limited spare
capacity within the frame
Actual user Um interface rate increases from
12kbps to 14.5kbps
HSCSD uses multiple slots of 14k4 to achieve data
rates of between 28k8 & 57.6kbps (19.2kbps 38.4kbps without sufficient C/I ratio)
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HSCSD two-slot operation
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GSM
Data
Nokia 2140 with CS data card (9k6)
Nokia HSCSD data card (28k8)
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GSM with Circuit and Packet
Switched data
PCU - Packet Core interface (Gb) was implemented using Frame Relay technology
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Option GPRS data card
GPRS Coverage
Coding Schemes




CS1 = 9.05kbps
CS2 = 13.4kbps
CS3 = 15.6kbps
CS4 = 21.4kbps
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GPRS – Coding Schemes
Service
1 slot
Class
2 slot
3 slot
4 slot
5 slot
6 slot
7 slot
8 slot
CS1
9.05
18.1
27.15
36.2
45.25
54.3
63.35
72.4
CS2
13.4
26.8
40.2
53.6
67
80.4
93.8
107.2
CS3
15.6
31.2
46.8
62.4
78
93.6
109.2 124.8
CS4
21.4
42.8
64.2
85.6
107
128.4 149.8 171.2
Data rates in kbps
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CSD - HSCSD - GPRS - EDGE
Nokia 7110
Ericsson
R380
Nokia 9210
Nokia 6230i
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IEEE802.11a/b/g - WiFi
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UMTS, data built in..
High speed packet data –
HSDPA, HSUPA, HSPA,
HSPA+
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UMTS timeline
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•
•
•
•
•
1991 – ETSI establishes SMG5 to develop standards for UMTS
1992 – Global radio frequencies are reserved for UMTS
(92/93/94 – UK GSM networks launch)
1998 – ETSI & ARIB unite to form 3GPP
1999 – 3GPP published first version of UMTS standards (R99)
2000 – UK Spectrum auction
2001 – NTT DoCoMo launches the World’s first WCDMA network
2003 – First UMTS networks launch in UK
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UMTS with Circuit and Packet
Switched data
UMTS terrestrial interfaces were implemented with ATM technology
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Mobile data cards
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Mobile data growth
(Pre-smartphones and tablets)
8000
3G/HSDPA dongles
7000
3G (UMTS) launch
6000
TB/month
5000
4000
3000
2000
1000
0
2002
2003
2004
2005
2006
2007
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Source: Caroline Gabriel @ Rethink Technology Research Ltd
Introduction to HSDPA
 HSDPA = High Speed Downlink Packet Access
 3GPP standard since Release 5 (2002)
 It is the first step in what’s known as ‘WCDMA Evolved’
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HSDPA channel
 Each code (physical channel) is known as a HS-PDSCH (High Speed Physical Downlink Shared Channel)
 The 3G channel rate is 240ksps
 Therefore the channel bit rate is:
– 480kbps with QPSK applied
– 960kbps with 16QAM applied
 A fixed spreading factor of 16 suggests 15 codes available at this level
(control information further down the chain on the 16th)
 Therefore the maximum physical layer bit rate is:
– (240 x 4) 960 x 15 = 14.4Mbps
 Not an actual user data rate!!!
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The need for higher
order modulation
 Since it’s possible to achieve a high C/I ratio the capacity of the HSDSCH can easily be exhausted
 Due to the channel structure it is not possible to send at higher data rates
even if the radio environment allows it
 Therefore a higher level modulation scheme is introduced in HSDPA thus
allowing higher data rates to be achieved under favourable radio
conditions
 Although used as a compliment to QPSK, 16QAM is therefore mandatory
if really high data rates are to be achieved
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Mobile data dongles
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Mobile data rate evolution
300Mbps
today,
>400Mbps
next year and
then speeds
of 1Gbps and
greater…
14.4Mbps
7.2Mbps
3.6Mbps
1.8Mbps
384kbps
171kbps
28.8kbps
14.4kbps
9.6kbps
1992
-
1997
-
2002
-
2007
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Mobile data growth
(Pre-smartphones and tablets)
8000
3G/HSDPA dongles
7000
3G (UMTS) launch
6000
TB/month
5000
4000
3000
2000
1000
0
2002
2003
2004
2005
2006
2007
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Source: Caroline Gabriel @ Rethink Technology Research Ltd
Summary
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•
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This talk focused on mobile data evolution between 1992 and
2007 - just 15 years!
Future historians will likely commemorate the current era as
The Technological Revolution - it’s important that we document
and conserve artefacts of this period, given the speed of
change and desire to always have the latest gadget - what
happens to the ‘old stuff’
GSM supported circuit switched data from the early to mid
1990’s
GPRS network appeared from the year 2000 onwards and
enhanced with EDGE technology a few years later
UMTS networks launched from 2003 while HSDPA
enhancements started to appear from 2006
Mobile data services have truly liberated the laptop!
Check out: http://www.engagingwithcommunications.com/
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Thank You!
Any question?
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