Digital Radio Microphone in Japan

1. [gsc12_grsc5_15] Digital Radio Microphone in Japan Studies for use in the 800 MHz band in Japan Shouhei Taniguchi (ARIB)

2. [Digital Radio Microphone in Japan] □ 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. Background

3. [Digital Radio Microphone in Japan] □ 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 Digital Specification in Japan: The basics

4. F.S.L [Digital Radio Microphone in Japan] RF Characteristics of the prototype Dynamic Range @BER=1e-6: 65dB 100m 10m 1m

5. [Digital Radio Microphone in Japan] Maximum number of channels for simultaneous operation Analogue 6 channels /4 MHz Channel allocation have to be considered 3rd-order distortion at receiver Digital 10 channels /4 MHz Channel could be allocated with equal spacing

6. [Digital Radio Microphone in Japan] Minimum distance between service areas to avoid interference Definition of service area and interfered area 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. Comparison of no interfered area between Analogue vs. Digital Analogue Digital Required D/U ratio: 40dB Required D/U ratio: 20 dB Interference-free distance: 30m Interfered area Radius: 90m Interference-free distance: 180m 干渉 エリア Interfered area Radius: 240m 干渉 エリア ： Service area Radius: 60m サービスエリア Service area Radius: 60m Radio barrier Attenuation: 15dB Radio barrier Attenuation: 15dB Minimum distance: 30m Minimum distance: 180m Comparison of interference-free distance between digital and analogue systems: 1/6 (30m/180m)

7. [Digital Radio Microphone in Japan] Capable number of interference-free areas Analogue Digital Minimum distance 180 m Minimum distance 30 m Required D/U ratio: 40 dB Required D/U ratio: 20 dB 300 m 150 m Number of interference-free areas: 19 Number of interference-free areas: 7 Possible number of interference-free areas in digital: 2.7 times (19/7)

8. 300m 150m [Digital Radio Microphone in Japan] Capable number of interference-free areas at Interleave allocation Definition of service area and interfered area Analogue Digital Coverage Radius: 60m Minimum distance 180 m Minimum distance 30 m Interleave allocation: No Interleave Allocation: Yes Received Antenna Not permitted area to use at 250kHz frequency interleave allocation Radius: 6m Service Area under basic channel allocation Increased Service Area under basic channel allocation in Digital Service Area under 250kHz frequency interleave allocation Number of interference-free areas: 31 Number of interference-free areas: 7 Possible number of interference-free areas in digital: 4.4 times (31/7)

9. [Digital Radio Microphone in Japan] Audio Quality 1: SNR Audio response @ 1kHz sign wave input Analogue Digital SNR is improved more than 20 dB

10. ◆Mean Value 95% Confidence Interval [Digital Radio Microphone in Japan] Audio Quality 2: transparent codec examination based on ITU-R BS1116-1 Result as the transparent quality To achieve the transparent quality for audio at Codec Delay : 3.7083ms and 192kbps

11. ◆Mean Value 95% Confidence Interval [Digital Radio Microphone in Japan] Audio Quality 3: transparent codec examination based on ITU-R BS1116-1 Result as the transparent quality To achieve the transparent quality for human voice at Codec Delay : 5.5625ms and 128kbps

12. [Digital Radio Microphone in Japan] □ 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 ) The Conclusion of Digital Advantages