Perspectives in risk management in Italy: the impact of WiMAX and WiFi

1
Perspectives in risk management in Italy the
impact of WiMAX and WiFi

• Dr. Ing. M. Mozzo, Dr. Ing. F. Boella, Dr. Ing.
  F. Panin, Prof. L.Giuliani
• Istituto Superiore per la Prevenzione e la
  Sicurezza del Lavoro
• 17/12/07

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Summary

• What is Wi-Fi?
• What is WiMAX?
• Wi-MAX tender in Italy
• capacity of WIMAX
• WIMAX scenario
• another scenario
• increasing the frequency ...
• bibliography

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What is Wi-Fi?

• Stands for Wireless Fidelity (1997)
• Wireless network extension of already existent
  successful Ethernet LAN.
• 2,4 GHz Free frequency band with limited power
  emission.
• Multiple Access with collision avoidance.
• prone to interference signals by other
  access-point
• DS and FH Spread-spectrum modulation and OFDM
  multiplexing
• Portable and mobile stations

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Wi-Fi Cell coverage and throughput (declared by
manufacturer )

• Access Point (Outdoor)
• Frequency bands 100 MHz near 2.4 and 5.7 GHz
• Transmit Power up to 100 mW (20 dBm)
• Minimum useful signal
• -94 dBm (1 Mbps) -72 dBm (54 Mbps)
• Throughput and range
• 54 Mbps 4560 m
• 11 Mbps 190235 m
• Antenna gain at access point 5 13 dBi

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Impact of Wi-Fi to radio environment

• The scenario is going to be hot-spotted isolated
  coverage with 100mW at 2,4GHz
• unlicensed ISM bands (industrial, scientific
  medical)
• freely maintained by local administrators
• in public areas (airport, train station, office,
  school park, etc.)

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What is WiMAX?

• Stands for World-wide Interoperability for
  Microwave Access.
• also known as Wi-fi maximized
• The industry trade group WiMAX ForumTM has
  defined WIMAX as the last mile broadband
  wireless access (BWA) alternative to ADSL
  service.

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specifications

• 2004 Air Interface for Fixed Broadband Wireless
  Access Systems (IEEE 802.16) whose primary bands
  of interest are 10-66 GHz, where line-of-sight
  (LOS) is necessary and multipath negligible.
• Frequency below 11GHz provide a physical
  environment where, due to longer wavelength, LOS
  is not necessary and multipath may be
  significant.
• many physical layer specifications (PHY)

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specification (continued)

• The ability to support near-LOS and non-LOS
  (NLOS) scenarios requires additional
  functionality, such as the support of advanced
  power management techniques, interference
  mitigation/coexistence and multiple antennas
• the wirelessMAN-OFDM is based on OFDM modulation
  and designed for NLOS operations in the frequency
  bands below 11GHz
• 2005 Mobile amendment (IEEE 802.16e) .

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some technical details

• At 3,5GHz, wavelength is 8cm and radiowave can
  reach 50Km, pass through trees and rain
  (drizzle).
• Robust narrow-band modulations (QPSK,QAM)
• 100 sub-carrier
• frequency or time duplexing

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Wi-MAX tender in Italy

• Published on 19th October 2007
• To licence the use of frequency bands allocated
  at 3.5 GHz using Broadband Wireless Access (BWA)
  systems
• Constrains to radio emissions (Maximum EIRP and
  Block Edge Mask as usual) in Raccomandazione n.
  ECC/REC(04)05
• 48 applicants

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Possible applications of Wi-MAX

• Besides last mile broadband wireless access in
  rural areas to overcome the digital divide,
  possible application are
• fixed telephony competitor
• mobile telephony competitor
• Transport network (backhaul) competitor of radio
  links or fibre between Wi-fi access points or
  mobile telephony towers

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Tipical Cell coverage and throughput (declared
goals)

• 10Km NLOS point-to-multipoint 40Mbps to mobile,
  portable and fixed
• 50Km LOS point-to-point 72Mbps to portable and
  fixed only.
• anyway these features become of second order as
  far as regards maximizing subscribers gt capacity
  constrains.

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capacity of WIMAX

• (21)x2 frequency bands of 21MHz
• adaptable bit/symbol depending by radio-path
  impairments (one symbol can use many carriers)
• Telco operators usually makes maximum use of
  limited spectrum assets gt cellular system

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WIMAX scenario

• Telco operators could implement a cellular system
  to substitute telephone copper wire to subscriber
  home, system that resembles the already existent
  one for the mobile telephony

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system profile

• example of an implementation case
• Antennas, receivers, powers, radio paths and
  above all interference are almost the same as GSM
  mobile scenario

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another scenario

• Telco operators could provide broadband wireless
  access in rural areas
• paraboloidal antenna can be used even though at
  3,5GHz they are not so well performing (with a
  diameter of 80cmgtonly 25dB gain, beamwidth 10 )
• Rabio base-subscriber home radio channel
  resembles a radio link

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increasing the frequency ...

• Operators could reuse the spectrum deploying the
  narrow beam of very directional antennas
  (paraboloidal) from a high tower
• In this case also the user antenna should be
  paraboloidal gt fixed (not mobile)
• In this scenario, a narrow beam covers a village
  from a distant high tower.

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Link budget example for DL mobile WiMAX

• Total TX Power 20 W
• Power used for link budget 10 W
• Penetration Loss 15 dB
• Minimum useful signal -75 dBm (68 dBµV/m)

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UMTS tech overview

• Frequency bands
• 19201980 MHz (UL) and 21102170 MHz (DL)
• Max number of (voice) channels on 2x5MHz 196
• Max user data rate offered 2 Mbps (DL)
• Antenna directional gain 1718.5 dBi

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Link budget example for DL UMTS

• Total sector TX Power 43 dBm (20 W)
• PCPICH 33 dBm (2 W)
• Penetration Loss 15 dB
• Minimum useful signal -78 dBm (66 dBµV/m)

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Ray-tracing simulation techniqueQuick_PlanTM by
TeS

• Full 3D ray-tracing
• Integrated Geographical Information System (GIS)
• Oracle DBMS
• Integrated 3D cartography
• (terrain buildings)

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UMTS coverage
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UMTS far-field exposition
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WiMAX coverage
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WiMAX far-field exposition
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bibliography

• ANSI/IEEE Std 802.11, 1999 Edition (R2003) Part
  11 Wireless LAN Medium Access Control (MAC) and
  Physical Layer (PHY) Specifications
• Cisco Aironet Antennas and Accessories
• IEEE standard 802.16-2004 Part16Air Interface
  for fixed broadband wireless Access System
• Eklund IEEE standard 802.16 A technical
  overwiev of he wirelessMAN air interface for
  broadband wireless access June 2002
• Webb Broadband fixed wireless access as a key
  component of the future integrated communication
  environment 2001