SQNR Improvement Enabled by Nonuniform DAC Output Levels for IM-DD OFDM Systems
We propose and demonstrate via both simulation and experiment a scheme for a low-bit resolution digital-to-analog convertor (DAC) to improve the signal-to-quantification noise ratio (SQNR) of an intensity-modulated direct-detection (IM-DD) orthogonal frequency division multiplexing (OFDM) signal. In...
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| Language: | English |
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IEEE
2017-01-01
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| Series: | IEEE Photonics Journal |
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| Online Access: | https://ieeexplore.ieee.org/document/7845673/ |
| _version_ | 1819168342616834048 |
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| author | Jizong Peng Lei Han Qingming Zhu Ciyuan Qiu Yong Zhang Christine Tremblay Yikai Su |
| author_facet | Jizong Peng Lei Han Qingming Zhu Ciyuan Qiu Yong Zhang Christine Tremblay Yikai Su |
| author_sort | Jizong Peng |
| collection | DOAJ |
| description | We propose and demonstrate via both simulation and experiment a scheme for a low-bit resolution digital-to-analog convertor (DAC) to improve the signal-to-quantification noise ratio (SQNR) of an intensity-modulated direct-detection (IM-DD) orthogonal frequency division multiplexing (OFDM) signal. In this scheme, the discrete output levels of a DAC are nonuniform and properly assigned based on the distribution of the OFDM signal. Such nonuniformity allows a better exploitation of output levels for the OFDM signal so that low-level waveforms that appear much more frequently experience mitigated quantization noise. To calculate these optimized output levels with the distribution of an OFDM signal, a numerical algorithm is proposed and verified. Our proposed scheme is proven effective in the simulations for Gaussian-distributed signals and brings over 3.6-dB and ~2.5-dB improvements on SQNR and receiver sensitivity, respectively. The feasibility is also verified by a proof-of-concept experiment with ~7.4-Gbps quadrature phase shift keying (QPSK)-modulated OFDM signals output by a 3-bit DAC. Our scheme enables transmission of such signals with no further optimization with ~-25-dBm receiver sensitivity, while it is impossible using a conventional way. Both simulation and experimental results validate our scheme as a promising way to be implemented in low-bit resolution DACs for IM-DD OFDM applications. |
| first_indexed | 2024-12-22T19:02:05Z |
| format | Article |
| id | doaj.art-a87011d8b82a48bdb85335fa7defaff0 |
| institution | Directory Open Access Journal |
| issn | 1943-0655 |
| language | English |
| last_indexed | 2024-12-22T19:02:05Z |
| publishDate | 2017-01-01 |
| publisher | IEEE |
| record_format | Article |
| series | IEEE Photonics Journal |
| spelling | doaj.art-a87011d8b82a48bdb85335fa7defaff02022-12-21T18:15:54ZengIEEEIEEE Photonics Journal1943-06552017-01-019211110.1109/JPHOT.2017.26649187845673SQNR Improvement Enabled by Nonuniform DAC Output Levels for IM-DD OFDM SystemsJizong Peng0Lei Han1Qingming Zhu2Ciyuan Qiu3Yong Zhang4Christine Tremblay5Yikai Su6State Key Laboratory of Advanced Optical Communication Systems and Networks, Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, ChinaState Key Laboratory of Advanced Optical Communication Systems and Networks, Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, ChinaState Key Laboratory of Advanced Optical Communication Systems and Networks, Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, ChinaState Key Laboratory of Advanced Optical Communication Systems and Networks, Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, ChinaState Key Laboratory of Advanced Optical Communication Systems and Networks, Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, ChinaLaboratoire de technologies de réseaux, École de technologie supérieure, Montréal, CanadaState Key Laboratory of Advanced Optical Communication Systems and Networks, Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, ChinaWe propose and demonstrate via both simulation and experiment a scheme for a low-bit resolution digital-to-analog convertor (DAC) to improve the signal-to-quantification noise ratio (SQNR) of an intensity-modulated direct-detection (IM-DD) orthogonal frequency division multiplexing (OFDM) signal. In this scheme, the discrete output levels of a DAC are nonuniform and properly assigned based on the distribution of the OFDM signal. Such nonuniformity allows a better exploitation of output levels for the OFDM signal so that low-level waveforms that appear much more frequently experience mitigated quantization noise. To calculate these optimized output levels with the distribution of an OFDM signal, a numerical algorithm is proposed and verified. Our proposed scheme is proven effective in the simulations for Gaussian-distributed signals and brings over 3.6-dB and ~2.5-dB improvements on SQNR and receiver sensitivity, respectively. The feasibility is also verified by a proof-of-concept experiment with ~7.4-Gbps quadrature phase shift keying (QPSK)-modulated OFDM signals output by a 3-bit DAC. Our scheme enables transmission of such signals with no further optimization with ~-25-dBm receiver sensitivity, while it is impossible using a conventional way. Both simulation and experimental results validate our scheme as a promising way to be implemented in low-bit resolution DACs for IM-DD OFDM applications.https://ieeexplore.ieee.org/document/7845673/Orthogonal frequency division multiplexing (OFDM)modulation |
| spellingShingle | Jizong Peng Lei Han Qingming Zhu Ciyuan Qiu Yong Zhang Christine Tremblay Yikai Su SQNR Improvement Enabled by Nonuniform DAC Output Levels for IM-DD OFDM Systems IEEE Photonics Journal Orthogonal frequency division multiplexing (OFDM) modulation |
| title | SQNR Improvement Enabled by Nonuniform DAC Output Levels for IM-DD OFDM Systems |
| title_full | SQNR Improvement Enabled by Nonuniform DAC Output Levels for IM-DD OFDM Systems |
| title_fullStr | SQNR Improvement Enabled by Nonuniform DAC Output Levels for IM-DD OFDM Systems |
| title_full_unstemmed | SQNR Improvement Enabled by Nonuniform DAC Output Levels for IM-DD OFDM Systems |
| title_short | SQNR Improvement Enabled by Nonuniform DAC Output Levels for IM-DD OFDM Systems |
| title_sort | sqnr improvement enabled by nonuniform dac output levels for im dd ofdm systems |
| topic | Orthogonal frequency division multiplexing (OFDM) modulation |
| url | https://ieeexplore.ieee.org/document/7845673/ |
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