Hideaki Kimura General Manager, NTT Corporation kimura.hideaki@lab.ntt.co.jp

1. “Workshop on Disaster Relief Systems, Network Resilience and Recovery” (Istanbul, Turkey, 11 December 2012) Research and Development Technologies for Disaster Resistance Improvement- Voice Communication System without Power Supply - Hideaki Kimura General Manager, NTT Corporation kimura.hideaki@lab.ntt.co.jp

2. Presentation Outline 1. Background of research and development 2. Subjects in optical communication systems 3. Voice communication system without power supply 3.1. Technology for downstream signal 3.2. Technology for upstream signal 4. Conclusions and recommendations

3. Background of research and development Optical access system based on PON

4. Subject in optical communication systems Problem communication blackout during power failures

5. Subject in optical communication systems Possible solutions and required functions for PON

6. Voice communication systemwithout power supply System configuration

7. Voice communication systemwithout power supply Downstream system configuration

8. Voice communication systemwithout power supply Feasibility study of downstream system

9. Voice communication systemwithout power supply Upstream system configuration

10. Sparse  rarely overlap Frequency 800 Delay Dt 400 Time frame Voice communication systemwithout power supply Upstream system configuration - Blind Speech Separation (BSS) Technique - Histogram Mask width Mask Phase difference Mixing process model Phase difference clustering Sparseness of speech - Utilizing phase differences (delays) of each source (user) - Voice signals have sparseness property in the time-frequency domain * Phase differences clustering * Designing binary mask to pick up slots from each cluster

11. Voice communication systemwithout power supply • Upstream system configuration • Utilizing Multi Wavelength Light Sources • and Phase Difference Caused by GVD-

12. Voice communication systemwithout power supply Upstream system configuration - Frequency up-conversion-

13. Voice communication systemwithout power supply Upstream system configuration - System design with BSS and frequency up-conversion-

14. Voice communication systemwithout power supply Feasibility study - Simulation conditions-

15. Voice communication systemwithout power supply Feasibility study - Simulation results-

16. Voice communication systemwithout power supply Feasibility study - Experimental conditions-

17. Voice communication systemwithout power supply Feasibility study - Experimental results-

18. Conclusions and recommendations We introduced an optical access system that enables voice communication without power supply, which is an important problem of optical communication systems, during power failure in a user’s house. Proposed system employees low threshold Ge-diode radio technique and SCM for downstream signal and DSP techniques for upstream signal. Now, optical communication system is one of life lines such as water, electric, gas and so on. Furthermore, we think that an importance of communication system will be increase, certainly although there is habitat segregation with a mobile system.