Global Standards Collaboration (GSC) 14. Broadband Wireless Communication System for Public Safety. Homare Murakami, Masayuki Oodo, Hiroshi Harada NICT / ARIB. - PowerPoint PPT Presentation
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Fostering worldwide interoperabilityGeneva, 13-16 July 2009
Broadband Wireless Communication Systemfor Public Safety
Fostering worldwide interoperability 2Geneva, 13-16 July 2009
Background – frequency band–
In Japan, digitalization of terrestrial TV broadcasting service to be completedin July, 2011 == > reduce the total bandwidth for terrestrial TV broadcasting
current
after July, 2011
current analog TV broadcasting (total: 370 MHz)
90 108 170 205 222 470 710 720 730 770[MHz]
3.ITS 4.cellular system
terrestrial digital TV broadcasting (240 MHz)
==> 130 MHz newly available2. Broadband mobile communications for public safety
90 108 170 222 470 770 [MHz]
1.mobile multimediabroadcasting
Fostering worldwide interoperability 3Geneva, 13-16 July 2009
Strategic Direction– current and expected systems for public safety–
broadbandshared by multiple public organizations
narrow band
fire department
local government(prefectural/city/municipal)
police agencies
narrow band
difficulty in interoperability
current system-- narrow band voice low data rate transmission-- difficulty in interoperability
-- shared by multiple public organizations-- broadband access service (several Mbps) for mobile users (main application: moving pictures transmission)-- highly-efficient spectrum use => OFDM-based system
expected system
Fostering worldwide interoperability 4Geneva, 13-16 July 2009
Challenges for reliability(1/2) – Radio Propagation Field Tests –
0 5 10 15 20 25 30-50
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delay spread: => ~ 10usec
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fading performance:=> slow temporal variation
RSSI measurement=> coverage ~ 5 km
P4
Fostering worldwide interoperability 5Geneva, 13-16 July 2009
Challenges for reliability (2/2) – Transmission Experiments –
In order to investigate adequate OFDM parameters, following combinations were tested.
For long-delayed (~ 20μsec) channel environment,Mode2 (narrower subcarrier interval, resulted in good transmission performance.
For short-delayed (~ 5μsec) channel environment, no large differences among all modes were seen.
Fostering worldwide interoperability 6Geneva, 13-16 July 2009
Toward the realization of broadband wireless communication system for public safety using the VHF bands (a portion of vacant lots after retirement of analog TV broadcasting service),
R & D of the system have been progressed.Indoor and Field experiments have been conducted
to decide the system parameters (service coverage, PHY parameters etc.).