Digital Radio Microphone in Japan

Digital Radio Microphone in Japan

Studies for use in the 800 MHz band

in Japan

Shouhei Taniguchi (ARIB)

[gsc12_grsc5_15]

SOURCE: ARIB

TITLE: Digital Radio Microphones in Japan

AGENDA ITEM: GRSC-5 5.6

CONTACT: [email protected]

□ Application: broadcast and non-broadcast.□ Popularization: the amount units are currently over the 2.4 million units as

general and various purpose and tends growth in Japan.□ Operational problem: the interference between the each operation and a lack

of channel at urban crowded area has been more serious recently, the analogue, however, had no way to solve these problems.

□ Latency Problem: The transparent codec that has less than 10ms latency and 1/5 compression has been successfully developed and its ability has been confirmed at official examination.

□ Transmission Reliability: To achieve the acceptable transmission error caused by fading used to be hard in high frequency transmission over 1GHz, or the propagation of wide band width over 500kHz, but the reliability of transmission in 800MHz has been confirmed at the official examination.

□ Functional requirements: the secured transmission at concert and conference, and remote and automatic operation by duplex communication.

□ Japanese Standardization: The digital radio law and the standard for general purpose will be comprised based on this results in Japan.

SOURCE: ARIB



CONTACT: [email protected] [Digital Radio Microphone in Japan]

Background

□ Applications: general purpose for broadcast, concerts, conventions, and various events at public halls, hotels, universities, school, shopping malls, department stores, etc.□ Frequency: 806.125MHz – 809.750MHz□ Antenna Power: Less than 10mW□ Modulation: QPSK, FSK, ASK, QAM ( without carrier modulation)□ Transmission data speed: 128ksps□ Audio performance: Dynamic Range more than 96dB, Frequency up to 15kHz □ Latency: Less than 10msec

SOURCE: ARIB




Digital Specification in Japan: The basics

1.00E- 07

1.00E- 06

1.00E- 05

1.00E- 04

1.00E- 03

1.00E- 02

1.00E- 01

5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85

Received Input Voltage[dBμ V]

ＢＥ

Ｒ

SOURCE: ARIB




RF Characteristics of the prototype

Dynamic Range @BER=1e-6: 65dB

10m 1m100m

F.S.L

SOURCE: ARIB




Maximum number of channels for simultaneous operation

806.125

806.500

806.750

807.000

807.250

807.500

806.250

807.750

808.000

808.250

808.500

808.750

809.000

809.250

809.500

809.750

810.000Minimum Spacing

250kHzOBW

110kHz

Channel allocation have to be considered 3rd-order distortion at receiver

806.125

806.500

806.750

807.000

807.250

807.500

806.250

807.750

808.000

808.250

808.500

808.750

809.000

809.250

809.500

809.750

810.000

Minimum Spacing375kHz

OBW192kHz

AnalogueAnalogue

DigitalDigital

6 channels/4 MHz

6 channels/4 MHz

10 channels/4 MHz

10 channels/4 MHz

Channel could be allocated with equal spacing

Analogue Analogue

Comparison of no interfered area between Analogue vs. Digital

Comparison of no interfered area between Analogue vs. Digital

Digital Digital

Minimum distance: 180mMinimum distance: 180m

Minimum distance: 30mMinimum distance: 30m

干渉エリア：

サービスエリア

干渉エリア Interference-free distance: 180m

Interference-free distance: 30m

Service areaRadius: 60m

Service areaRadius: 60m

Interfered area

Radius: 240m

Interfered area

Radius: 90m

Required D/U ratio: 40dB Required D/U ratio: 40dB Required D/U ratio: 20 dB Required D/U ratio: 20 dB

Radio barrierAttenuation: 15dB

Radio barrierAttenuation: 15dB

Comparison of interference-free distance between digital and analogue systems: 1/6 (30m/180m)

Comparison of interference-free distance between digital and analogue systems: 1/6 (30m/180m)

Service area: Whole operable area around a receiving antenna. (Radius is 60 m) Interfered area: Area where operation of two radio microphones at the same frequency is impossible. Assumed attenuation by obstacles is 15dB （ Area where D/U for a radio microphone at the circumference cannot be satisfied.

Definition of service area and interfered area


SOURCE: ARIB




Minimum distance between service areas to avoid interference

SOURCE: ARIB




Capable number of interference-free areas

Minimum distance 180 mMinimum distance 180 m Minimum distance 30 mMinimum distance 30 m

Required D/U ratio: 40 dBRequired D/U ratio: 40 dB

Required D/U ratio: 20 dBRequired D/U ratio: 20 dB

150 m300 m

Analogue Analogue

Possible number of interference-free areas in digital: 2.7 times (19/7)


Number of interference-free areas: 7




Digital Digital

SOURCE: ARIB




Capable number of interference-free areas at Interleave allocation

Minimum distance 180 mMinimum distance 180 m Minimum distance 30 mMinimum distance 30 m

Interleave allocation: NoInterleave allocation: No Interleave Allocation: YesInterleave Allocation: Yes

Analogue Analogue







Digital Digital

Service Area under basic channel allocation Increased Service Area under basic channel allocation in Digital Service Area under 250kHz frequency interleave allocation

Service Area under basic channel allocation Increased Service Area under basic channel allocation in Digital Service Area under 250kHz frequency interleave allocation

300m 150m

Coverage Radius: 60m

Received Antenna

Not permitted area to use at 250kHz frequency interleave allocation Radius: 6m



SOURCE: ARIB




Audio Quality 1: SNR

Analogue Analogue Digital Digital

Audio response @ 1kHz sign wave input

SNR is improved more than 20 dBSNR is improved more than 20 dB

SOURCE: ARIB




Audio Quality 2: transparent codec

Esti mated del ay=3. 7083msec

-4. 000

-3. 500

-3. 000

-2. 500

-2. 000

-1. 500

-1. 000

-0. 500

0. 000

0. 500

1. 000

192kbps 128kbps 192kbps 128kbps 192kbps 128kbps 192kbps 128kbps 192kbps 128kbps

Orig

inal

Sou

rce

- Av

erag

e of

est

imat

ed s

ound

Qual

ity

Femal e Vocal s Mal e Speech Femal e Speech Base Sol o Drums sol o

To achieve the transparent quality for audio at Codec Delay : 3.7083ms and 192kbps

To achieve the transparent quality for audio at Codec Delay : 3.7083ms and 192kbps

95% Confidence Interval

◆ Mean Value

Result as the transparent quality

examination based on ITU-R BS1116-1

SOURCE: ARIB




Audio Quality 3: transparent codec

Esti mated del ay: 5. 5625msec

-4. 000

-3. 500

-3. 000

-2. 500

-2. 000

-1. 500

-1. 000

-0. 500

0. 000

0. 500

1. 000

128kbps 96kbps 128kbps 96kbps 128kbps 96kbps 128kbps 96kbps 128kbps 96kbpsOriginal Source - Average of estimated sound Qualit

Femal e Vocal s Mal e Speech Femal e Speech Base Sol o Drums sol o

To achieve the transparent quality for human voice at Codec Delay : 5.5625ms and 128kbps

To achieve the transparent quality for human voice at Codec Delay : 5.5625ms and 128kbps

95% Confidence Interval

◆ Mean Value

Result as the transparent quality

examination based on ITU-R BS1116-1

□ Maximum number of simultaneous operable channel: 10 channels (vs. analogue: 6 channels )□ Minimum distance to avoid interference: 30m (vs. analogue: 180m )□ Capable number of interference-free areas : 19 ( vs. Analogue: 7 )□ Capable number of interference-free areas considering the

placement by frequency interleave : ( vs. Analogue: No )□ Secured communication : Yes ( vs. Analogue: No )□ Remote operation and the other transmitted information: Possible ( vs. Analogue: Impossible )

SOURCE: ARIB



CONTACT: [email protected][Digital Radio Microphone in Japan]

The Conclusion of Digital Advantages

Digital Radio Microphone in Japan

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