1. Telecommunications for the future - 3
Rob Parker
CERN IT Division

2. Mobile (wireless) Wide area Local area Very short distance
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3. WIDE AREA WIRELESS
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4. Analogue Cellular Radio
Bell technical proposals following a request from the FCC
key objectives:
large subscriber capacity
efficient use of spectrum
nation-wide compatibility
widespread availability
adaptability to traffic density
service to vehicles and portable stations
telephone quality of service
affordability
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5. Analogue Cellular Radio
Field trials in Chicago of Bell system
Advance Mobile Phone System
1980+ widespread introduction around the world of analogue cellular systems loosely based on AMPS:
Total Access Cellular System (TACS)
900 MHz derivative of AMPS
Nordic Mobile Telephone (NMT)
450 & 900 MHz versions
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6. Basic Cellular Concept
frequency re-use
base station
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7. GSM history international roaming ISDN compatibility
1982 Groupe Speciale Mobile” set up by the CEPT to study a pan-European digital cellular system, with similar aims to the Bell study, plus:
international roaming
ISDN compatibility
GSM renamed “Global System for Mobile communications”
GSM Phase 1 recommendations published
First operational GSM network
GSM Phase 2 recommendations published
5.5 million subscribers in 60 countries
1996 GSM Phase 2+ recommendations published annually
270 million subscribers in Europe alone!
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8. GSM services above all, telephony data services
circuit-switched connections up to 14.4 kbit/s
access to PSTN (modems) and ISDN
Group 3 fax
Short Message Service (SMS)
alphanumeric messages of up to 160 characters
delivery confirmation possible
Supplementary services
call forwarding, call waiting, etc.
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9. GSM Radio Aspects frequency bands
900 MHz & 1800 MHz (except N. America & Japan)
1900 MHz (N. America)
bands divided into 200 kHz carrier frequencies
each carrier frequency is divided into 8 time slots, or channels
TREND: cell sizes are getting smaller, to give higher capacity
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10. Enhancements to GSM (2.5G)
HSCSD
High-speed Circuit-Switched Data
GPRS
General Packet Radio Service
EDGE
Enhanced Data rates for GSM evolution
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11. HSCSD uses GSM air interface uses GSM core network
supports data rates up to 57.6 kbit/s
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12. GPRS uses GSM air interface new packet-switched core network
supports data rates up to kbit/s
always connected
simultaneous voice and data
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13. EDGE uses GSM air interface
8 PSK (eight-phase-shift keying) modulation
allows up to 48 kbit/s per timeslot (so 384 kbit/s if all 8 timeslots in a 200 kHz channel are used)
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14. 3G (Third generation) mobile
officially known as IMT-2000
(IMT = International Mobile Telecommunications)
frequencies: MHz; MHz
(these are not universally allocated, in particular, not yet in the USA)
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15. 3G data requirements circuit- and packet-switched data
symmetric and asymmetric services
data rates of:
up to at least 144 kbit/s in a moving vehicle
up to at least 384 kbit/s elsewhere
up to 2 Mbit/s with low mobility in pico cells (eg. Indoor office)
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16. 3G standards
There are several standards for 3G, the most important of which are:
UMTS (Universal Mobile Telecommunications Service)
CDMA2000
TD-CDMA
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17. LOCAL AREA WIRELESS (WIRELESS LAN)
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18. HIPERLAN 1 standardized by ETSI (EN 300 652) uses 5.15-5.30 GHz band
data rates up to 20 Mbit/s
channel access method: EY-NPMA
Elimination Yield Non-pre-emptive Multiple Access
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19. HIPERLAN 2 standardized by ETSI
IEEE a has only minor differences from HIPERLAN 2
uses GHz
data rates of 6, 9, 12, 18, 27, 36, & 54 Mbit/s
two operating modes
Centralized
Direct
mandatory Forward Error Correction
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20. IEEE 802.11b standardized by IEEE
uses the unlicensed 2.4 GHz ISM (Industrial, Scientific, & Medical band)
data rates: 1, 2, 5.5, & 11 Mbit/s
different transmission powers in N. America and Europe
security
Access Points can be programmed with a list of allowable MAC addresses
optional RSA encryption (40-bit key)
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21. IEEE 802.11b Spread Sprectrum
Two options for spread spectrum operation
FH (Frequency Hopping)
high user density, harsh environment
DS (Direct Sequence)
10BASE-T Ethernet rates, indoor & outdoor
These are fundamentally different, and will not interoperate with one another
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22. IEEE 802.b Operating Modes Infrastructure Ad hoc
also called Basic Service Set (BSS)
at least one Access Point is connected to the cabled network infrastructure; wireless stations have network access
Ad hoc
also called Independent Basic Service Set (IBSS)
a set of wireless stations that communicate only among themselves
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23. Wireless Local Loop (WLL)
useful for areas where ADSL does not, or cannot, reach
can provide a competitive solution
so standard yet in place
Proprietary standards
IEEE b
Later, HIPERLAN 2
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24. VERY SHORT RANGE WIRELESS
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25. Bluetooth
A short-range radio system intended to provide cable-replacement links between devices such as:
laptops
printers
mobile phones
PDAs
headsets
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26. Bluetooth characteristics
uses the unlicensed 2.4 GHz ISM
uses frequency hopping: 1600 hops per second
1 Mbit/s link speed
two link types can be established:
SCO (Synchronous Connection Oriented)
typically for voice
ACL (Asynchronous Connection less)
typically for data
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27. Other Bluetooth features
low cost
low power consumption
low complexity
can handle rapidly changing environment
can discover services within range
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