Fostering worldwide interoperabilityGeneva, 13-16 July 2009

Broadband Wireless Communication Systemfor Public Safety

Homare Murakami, Masayuki Oodo, Hiroshi HaradaNICT / ARIB

Global Standards Collaboration (GSC) 14

DOCUMENT #: GSC14-PLEN-071

FOR: Presentation

SOURCE: ARIB

AGENDA ITEM: 6.2

CONTACT(S): homa@nict.go.jp

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

-40

-30

-20

-10

0

time [usec]

rela

tive

am

pli

tud

e [d

B]

@P4d=1.6km

peak time+10sec

peak time+20sec

0

-10

-20

-30

-40

-500 10 20 30

time [sec]

rela

tive

pow

er [d

B]

0 5 10 15 20 25 30-50

-40

-30

-20

-10

0

time [usec]

rela

tive

am

pli

tud

e [d

B]

@P4d=1.6km

peak time+10sec

peak time+20sec

0

-10

-20

-30

-40

-500 10 20 30

time [sec]

rela

tive

pow

er [d

B]

delay spread: => ~ 10usec

@P4

frequency [MHz]

rela

tive

po

we

r [d

B]

5

0

-10

-20

-30

-40

-50

-60-5 0

time[msec]

0

200

100

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.

CNR vs BER（profileA，CTC r=1/ 2，QPSK）

1E-7

1E-6

1E-5

1E-4

1E-3

1E-2

1E-1

1E+0

5 10 15 20 25 30 35 40CNR[dB]

BE

R

mode2

mode3

mode4

CNR [dB]

BE

R

5 10 15 20 25 30

伝搬路モデル：802.22 Profile A

Mode1Mode2Mode3

0

10-1

10-2

10-3

10-4

10-5

10-6

10-7

CNR vs BER（profileA，CTC r=1/ 2，QPSK）

1E-7

1E-6

1E-5

1E-4

1E-3

1E-2

1E-1

1E+0

5 10 15 20 25 30 35 40CNR[dB]

BE

R

mode2

mode3

mode4

CNR [dB]

BE

R

5 10 15 20 25 30

Mode1Mode2Mode3

Mode1Mode2Mode3

0

10-1

10-2

10-3

10-4

10-5

10-6

10-7

CNR vs BER（typicalUrban，CTC，QPSK）

1E-7

1E-6

1E-5

1E-4

1E-3

1E-2

1E-1

1E+0

5 10 15 20 25 30 35 40CNR[dB]

BER

mode2

mode3

mode4

BE

R

伝搬路モデル：Typical Urban

CNR [dB]5 10 15 20 25 30

0

10-1

10-2

10-3

10-4

10-5

10-6

10-7

Mode1Mode2Mode3

CNR vs BER（typicalUrban，CTC，QPSK）

1E-7

1E-6

1E-5

1E-4

1E-3

1E-2

1E-1

1E+0

5 10 15 20 25 30 35 40CNR[dB]

BER

mode2

mode3

mode4

BE

RCNR [dB]

5 10 15 20 25 30

0

10-1

10-2

10-3

10-4

10-5

10-6

10-7

Mode1Mode2Mode3

Mode1Mode2Mode3

Mode # Mode 1 Mode 2 Mode 3Channel bandwidth 5 MHz 5 MHz 5 MHz

FFT Size 512 1024 1024Guard Interval ~10 μsec ~20 μsec ~20 μsec

Pilot symbol occupancy ~30% ~30% ~17%

GSM Typical UrbanIEEE 802.22 Profile A

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.).

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