2018 Fiscal Year Research-status Report
Novel fronthaul technology for massive and ultra-dense radio access networks
| Project/Area Number |
18K04156
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| Research Institution | National Institute of Information and Communications Technology |
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Principal Investigator |
PHAM TIENDAT 国立研究開発法人情報通信研究機構, ネットワークシステム研究所ネットワーク基盤研究室, 研究員 (50636321)
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| Co-Investigator(Kenkyū-buntansha) |
梅沢 俊匡 国立研究開発法人情報通信研究機構, ネットワークシステム研究所ネットワーク基盤研究室, 主任研究員 (20636047)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | wireless- wired / optical and mobile / Millimeter wave / Signal processing / communication systems |
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| Outline of Annual Research Achievements |
A subcarrier multiplexing intermediate frequency over fiber system was developed for transmission of three multiband signals in the microwave, 25-GHz, and 96-GHz bands over the system. A low phase noise carrier signal generation was also developed and distributed remotely to antenna sites for signal up-conversion to millimeter-wave bands. Using the developed technologies, we transmitted 10-Gb/s radio signals at 90-GHz band over 100 switched fiber links.
We also developed Nyquist-SCM signal processing for spectral-efficiency transmission of 10-subband 45-Gb/s mobile signal at 90 GHz over an optical system.
We also designed and fabricated a 100-GHz UTC-PD excluding a bias circuit with a responsivity over 0.13 A/W. 100-Gbaud NRZ signal was transmitted over a fiber link with good eye diagram performance.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
We successfully developed key techniques for a spectral-efficiency and high-speed FDM RoF for transmission of multiband and multiple-input multiple-output signals in the millimeter-wave bands over an optical fronthaul system. We also designed and fabricated a 100-GHz broadband UTC-PD that can be integrated into a receiver module for carrier signal generation. The achieved results have been presented in domestic and international conferences and published in international journals.
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| Strategy for Future Research Activity |
We will improve the algorithms developed in the first year for aggregating a large number of IF signals, mapping IF signals to several FDM RoF systems, and transmitting them over different parallel optical channels. We also will develop pre-emphasis techniques to compensate for nonlinear distortions and non-flat channel response of the FDM RoF systems. For the integrated receiver module, we will design, fabricate, and evaluate a receiver module including design and fabrication of the integrated receiver module with a photodetector chip and evaluate the characteristics and performance of the developed module. We will then conduct proof-of-concept experiments for high-speed FDM RoF system transmission.
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| Causes of Carryover |
In last year, I had some budget for travel expense to attend international conferences and buying some devices for experiments. Thus, I wanted to move the planned budget for last fiscal year to this year so that I can buy expensive items for experiments.
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