Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783698
H. Matsuo, E. Okamoto, Y. Iwanami, Y. Shoji, M. Toyoshima, Y. Takayama
We propose a new transmission scheme of multi-rate low density generator matrix (LDGM) code suitable for optical satellite communications. Since the proposed scheme doesn't utilize a preamble transmission of the rate information nor the repeat request scheme, a long feedback delay in the satellite link and a decrease of transmission efficiency can be avoided. Then, an adaptive rate transmission only with forward error correction (FEC) is achieved and the transmitter can choose the quality or the rate-efficiency of transmission from the transmitter-side state. In the receiver, an exact rate-decision and decoding are conducted without the preamble. It is shown that the proposed scheme is effective in the satellite-to-ground optical link by the computer simulations.
{"title":"Multi-rate low density generator matrix code for satellite laser communications","authors":"H. Matsuo, E. Okamoto, Y. Iwanami, Y. Shoji, M. Toyoshima, Y. Takayama","doi":"10.1109/ICSOS.2011.5783698","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783698","url":null,"abstract":"We propose a new transmission scheme of multi-rate low density generator matrix (LDGM) code suitable for optical satellite communications. Since the proposed scheme doesn't utilize a preamble transmission of the rate information nor the repeat request scheme, a long feedback delay in the satellite link and a decrease of transmission efficiency can be avoided. Then, an adaptive rate transmission only with forward error correction (FEC) is achieved and the transmitter can choose the quality or the rate-efficiency of transmission from the transmitter-side state. In the receiver, an exact rate-decision and decoding are conducted without the preamble. It is shown that the proposed scheme is effective in the satellite-to-ground optical link by the computer simulations.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125613518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783697
Jingyuan Fan, Xiaolin Zhou, Jun Liu
In this paper, we illustrate our attempt in an effective method of free space optical (FSO) communications. Firstly, a pulse-position modulated (PPM) optical interleave-division multiple-access (OIDMA) system is designed. Secondly, to alleviate the degrading effects of atmospheric turbulence, cooperative relay technique is adopted by OIDMA for achieving spatial diversity and robust transmission performance. Thirdly, to study the convergence behavior of the proposed relay-assisted optical PPM-OIDMA system, extrinsic information transfer (EXIT) charts are analyzed. By deriving the trajectories of the exchanged extrinsic information from EXIT charts, the time of iterations required for convergence can be easily predicted. The effects of scintillation, thermal noise, background noise and multi-user interference have been taken into consideration.
{"title":"Design and evaluation of an IDMA cooperative relay free-space optical system","authors":"Jingyuan Fan, Xiaolin Zhou, Jun Liu","doi":"10.1109/ICSOS.2011.5783697","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783697","url":null,"abstract":"In this paper, we illustrate our attempt in an effective method of free space optical (FSO) communications. Firstly, a pulse-position modulated (PPM) optical interleave-division multiple-access (OIDMA) system is designed. Secondly, to alleviate the degrading effects of atmospheric turbulence, cooperative relay technique is adopted by OIDMA for achieving spatial diversity and robust transmission performance. Thirdly, to study the convergence behavior of the proposed relay-assisted optical PPM-OIDMA system, extrinsic information transfer (EXIT) charts are analyzed. By deriving the trajectories of the exchanged extrinsic information from EXIT charts, the time of iterations required for convergence can be easily predicted. The effects of scintillation, thermal noise, background noise and multi-user interference have been taken into consideration.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130291281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783707
R. Cesarone, D. Abraham, S. Shambayati, J. Rush
Current key initiatives in deep-space optical communications are treated in terms of historical context, contemporary trends, and prospects for the future. An architectural perspective focusing on high-level drivers, systems, and related operations concepts is provided. Detailed subsystem and component topics are not addressed. A brief overview of past ideas and architectural concepts sets the stage for current developments. Current requirements that might drive a transition from radio frequencies to optical communications are examined. These drivers include mission demand for data rates and/or data volumes; spectrum to accommodate such data rates; and desired power, mass, and cost benefits. As is typical, benefits come with associated challenges. For optical communications, these include atmospheric effects, link availability, pointing, and background light. The paper describes how NASA's Space Communication and Navigation Office will respond to the drivers, achieve the benefits, and mitigate the challenges, as documented in its Optical Communications Roadmap. Some nontraditional architectures and operations concepts are advanced in an effort to realize benefits and mitigate challenges as quickly as possible. Radio frequency communications is considered as both a competitor to and a partner with optical communications. The paper concludes with some suggestions for two affordable first steps that can yet evolve into capable architectures that will fulfill the vision inherent in optical communications.
{"title":"Deep-space optical communications","authors":"R. Cesarone, D. Abraham, S. Shambayati, J. Rush","doi":"10.1109/ICSOS.2011.5783707","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783707","url":null,"abstract":"Current key initiatives in deep-space optical communications are treated in terms of historical context, contemporary trends, and prospects for the future. An architectural perspective focusing on high-level drivers, systems, and related operations concepts is provided. Detailed subsystem and component topics are not addressed. A brief overview of past ideas and architectural concepts sets the stage for current developments. Current requirements that might drive a transition from radio frequencies to optical communications are examined. These drivers include mission demand for data rates and/or data volumes; spectrum to accommodate such data rates; and desired power, mass, and cost benefits. As is typical, benefits come with associated challenges. For optical communications, these include atmospheric effects, link availability, pointing, and background light. The paper describes how NASA's Space Communication and Navigation Office will respond to the drivers, achieve the benefits, and mitigate the challenges, as documented in its Optical Communications Roadmap. Some nontraditional architectures and operations concepts are advanced in an effort to realize benefits and mitigate challenges as quickly as possible. Radio frequency communications is considered as both a competitor to and a partner with optical communications. The paper concludes with some suggestions for two affordable first steps that can yet evolve into capable architectures that will fulfill the vision inherent in optical communications.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116692919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783715
M. Grein, A. Kerman, E. Dauler, O. Shatrovoy, R. Molnar, D. Rosenberg, J. Yoon, C. Devoe, D. V. Murphy, B. Robinson, D. Boroson
In this paper we present a design for a photoncounting optical receiver—based on superconducting NbN nanowire detector arrays—that will be employed in the ground terminal for the NASA Lunar Laser Communications Demonstration. The ground receiver is designed with four, 40 cm apertures, each coupled to a novel multi-mode polarization-maintaining fiber. The receiver is designed to receive a variable-rate pulse-position-modulated signal with a maximum data rate of 622 Mb/s.
{"title":"Design of a ground-based optical receiver for the lunar laser communications demonstration","authors":"M. Grein, A. Kerman, E. Dauler, O. Shatrovoy, R. Molnar, D. Rosenberg, J. Yoon, C. Devoe, D. V. Murphy, B. Robinson, D. Boroson","doi":"10.1109/ICSOS.2011.5783715","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783715","url":null,"abstract":"In this paper we present a design for a photoncounting optical receiver—based on superconducting NbN nanowire detector arrays—that will be employed in the ground terminal for the NASA Lunar Laser Communications Demonstration. The ground receiver is designed with four, 40 cm apertures, each coupled to a novel multi-mode polarization-maintaining fiber. The receiver is designed to receive a variable-rate pulse-position-modulated signal with a maximum data rate of 622 Mb/s.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116824248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783693
A. Waseda, M. Sasaki, M. Takeoka, M. Fujiwara, M. Toyoshima, A. Assalini
We numerically evaluate the deep-space communication performance in a broadband lossy channel of coherent pulse position modulation (PPM) with on/off receiver. We also consider quadrature amplitude modulation (QAM) signal and phase-shift keying (PSK) signal with dyne-type detections. We find that for an extremely weak signal input power, multilevel PPM system is good strategy, while for an extremely strong signal, multilevel QAM system is recommended.
{"title":"Numerical evaluation of coherent signals for deep-space links","authors":"A. Waseda, M. Sasaki, M. Takeoka, M. Fujiwara, M. Toyoshima, A. Assalini","doi":"10.1109/ICSOS.2011.5783693","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783693","url":null,"abstract":"We numerically evaluate the deep-space communication performance in a broadband lossy channel of coherent pulse position modulation (PPM) with on/off receiver. We also consider quadrature amplitude modulation (QAM) signal and phase-shift keying (PSK) signal with dyne-type detections. We find that for an extremely weak signal input power, multilevel PPM system is good strategy, while for an extremely strong signal, multilevel QAM system is recommended.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115491771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783689
D. Raible, Brian Fast, D. Dinca, T. Nayfeh, Andrew Jalics
In an effort to further advance a realizable form of wireless power transmission (WPT), high intensity laser power beaming (HILPB) has been developed for both space and terrestrial applications. Unique optical-to-electrical receivers are employed with near infrared (IR-A) continuous-wave (CW) semiconductor lasers to experimentally investigate the HILPB system. In this paper, parasitic feedback, uneven illumination and the implications of receiver array geometries are considered and experimental hardware results for HILPB are presented. The TEM00 Gaussian energy profile of the laser beam presents a challenge to the effectiveness of the receiver to perform efficient photoelectric conversion, due to the resulting non-uniform illumination of the photovoltaic cell arrays. In this investigation, the geometry of the receiver is considered as a technique to tailor the receiver design to accommodate the Gaussian beam profile, and in doing so it is demonstrated that such a methodology is successful in generating bulk receiver output power levels reaching 25 W from 7.2 cm2 of photovoltaic cells. These results are scalable, and may be realized by implementing receiver arraying and utilizing higher power source lasers to achieve a 1.0 m2 receiver capable of generating over 30 kW of electrical power. This type of system would enable long range optical ‘refueling’ of electric platforms, such as MUAV's, airships, robotic exploration missions and provide power to spacecraft platforms which may utilize it to drive electric means of propulsion. In addition, a smaller HILPB receiver aperture size could be utilized to establish a robust optical communications link within environments containing high levels of background radiance, to achieve high signal to noise ratios.
{"title":"Comparison of square and radial geometries for high intensity laser power beaming receivers","authors":"D. Raible, Brian Fast, D. Dinca, T. Nayfeh, Andrew Jalics","doi":"10.1109/ICSOS.2011.5783689","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783689","url":null,"abstract":"In an effort to further advance a realizable form of wireless power transmission (WPT), high intensity laser power beaming (HILPB) has been developed for both space and terrestrial applications. Unique optical-to-electrical receivers are employed with near infrared (IR-A) continuous-wave (CW) semiconductor lasers to experimentally investigate the HILPB system. In this paper, parasitic feedback, uneven illumination and the implications of receiver array geometries are considered and experimental hardware results for HILPB are presented. The TEM00 Gaussian energy profile of the laser beam presents a challenge to the effectiveness of the receiver to perform efficient photoelectric conversion, due to the resulting non-uniform illumination of the photovoltaic cell arrays. In this investigation, the geometry of the receiver is considered as a technique to tailor the receiver design to accommodate the Gaussian beam profile, and in doing so it is demonstrated that such a methodology is successful in generating bulk receiver output power levels reaching 25 W from 7.2 cm2 of photovoltaic cells. These results are scalable, and may be realized by implementing receiver arraying and utilizing higher power source lasers to achieve a 1.0 m2 receiver capable of generating over 30 kW of electrical power. This type of system would enable long range optical ‘refueling’ of electric platforms, such as MUAV's, airships, robotic exploration missions and provide power to spacecraft platforms which may utilize it to drive electric means of propulsion. In addition, a smaller HILPB receiver aperture size could be utilized to establish a robust optical communications link within environments containing high levels of background radiance, to achieve high signal to noise ratios.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122610567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783719
H. Hemmati, W. Farr, A. Biswas, K. Birnbaum, W. Roberts, K. Quirk, S. Townes
We report on engineering trades that led to the conceptual design of a laser communications terminal for a spacecraft orbiting Mars. The flight terminal, the ground receiver and the ground transmitter subsystems are described. The designed system is capable of 0.25 Gb/s downlink data-rate, 0.3 Mb/s uplink data-rate, and ranging with a 30 cm precision when the distance to the flight terminal is the Earth-Mars close range (0.42 AU).
{"title":"Deep-space optical terminals","authors":"H. Hemmati, W. Farr, A. Biswas, K. Birnbaum, W. Roberts, K. Quirk, S. Townes","doi":"10.1109/ICSOS.2011.5783719","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783719","url":null,"abstract":"We report on engineering trades that led to the conceptual design of a laser communications terminal for a spacecraft orbiting Mars. The flight terminal, the ground receiver and the ground transmitter subsystems are described. The designed system is capable of 0.25 Gb/s downlink data-rate, 0.3 Mb/s uplink data-rate, and ranging with a 30 cm precision when the distance to the flight terminal is the Earth-Mars close range (0.42 AU).","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124099016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783705
T. Takano
Optical antennas or light-wave antennas have partly similarities and differences with optical telescopes and radio-wave antennas, respectively. This paper first describes the features of light-wave antennas and seeks for the direction of their R&D in the future. Then, the research works that we achieved in laboratory so far will be explained. Those results are expected to bridge the gap between the light-wave antennas and both of light-wave application systems and radio-wave antennas.
{"title":"Light-wave antenna: Is it a simple extension of optical telescopes?","authors":"T. Takano","doi":"10.1109/ICSOS.2011.5783705","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783705","url":null,"abstract":"Optical antennas or light-wave antennas have partly similarities and differences with optical telescopes and radio-wave antennas, respectively. This paper first describes the features of light-wave antennas and seeks for the direction of their R&D in the future. Then, the research works that we achieved in laboratory so far will be explained. Those results are expected to bridge the gap between the light-wave antennas and both of light-wave application systems and radio-wave antennas.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117216932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783701
E. Luvsandamdin, G. Mura, A. Wicht, A. Sahm, S. Spiessberger, H. Wenzel, G. Erbert, G. Trankle
We present a micro-integrated, high power, narrow linewidth extended cavity diode laser (ECDL) for precision quantum optics experiments at 780 nm onboard a sounding rocket. Although micro-integrated ECDL is based on a Littrow configuration, it features an excellent mechanical stability because any moveable parts were omitted. It provides an overall tuneability of 40 GHz and a continuous tuneability of 4 GHz. We have demonstrated a maximum output power of more than 120 mW, an intrinsic linewidth of approximately 3.6 kHz full-width-at-half-maximum (FWHM) at an output power of 62 mW and less than 50 kHz FWHM short term (10 µs) linewidth including technical noise. An upgraded version will provide an overall tuneability of 100 GHz and continous tuneability in excess of 20 GHz.
{"title":"Micro-integrated ECDLs for precision spectroscopy in space","authors":"E. Luvsandamdin, G. Mura, A. Wicht, A. Sahm, S. Spiessberger, H. Wenzel, G. Erbert, G. Trankle","doi":"10.1109/ICSOS.2011.5783701","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783701","url":null,"abstract":"We present a micro-integrated, high power, narrow linewidth extended cavity diode laser (ECDL) for precision quantum optics experiments at 780 nm onboard a sounding rocket. Although micro-integrated ECDL is based on a Littrow configuration, it features an excellent mechanical stability because any moveable parts were omitted. It provides an overall tuneability of 40 GHz and a continuous tuneability of 4 GHz. We have demonstrated a maximum output power of more than 120 mW, an intrinsic linewidth of approximately 3.6 kHz full-width-at-half-maximum (FWHM) at an output power of 62 mW and less than 50 kHz FWHM short term (10 µs) linewidth including technical noise. An upgraded version will provide an overall tuneability of 100 GHz and continous tuneability in excess of 20 GHz.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134096687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783695
Jiang Liu, Wasinee Noonpakdee, H. Takano, S. Shimamoto
In this paper, we present a novel relay system in which a radio frequency (RF) signal is relayed over optical media to provide wireless communications in RF sensitive areas. We refer to this as RF over Optical (RFoO). Different from conventional relay systems, we adopt RF band phase shift beamforming to adjust the initial phases of the RF signal before modulating it into the optical band. As a benefit, we are able to control the energy of the transmitted signal to concentrate it in desired areas. To reduce overhead and device loss we designed a simplified beamforming process which is based upon a predefined beam codebook. The relay station sends a series of ‘training sequences’ using each pre-defined beam pattern. Mobile devices estimate the Signal-To-Noise (SNR) ratio of these ‘training sequences’ to determine the optimal beam pattern, then informs the relay station of the optimal pattern. By properly designing the beam codebook, the proposed system is capable of providing wider coverage of a service area with multiple beams, and achieving stronger received power at the mobile terminal than non-beamformed radiation system. Compared to other beam control schemes, the proposed scheme is easy to implement and allows for very quick beam changes. We provide a theoretical analysis followed by computer simulation. Our simulation results show that this system can effectively enhance the received power and improve the BER performance of Optical Wireless Communications.
在本文中，我们提出了一种新的中继系统，其中射频(RF)信号在光介质上中继，以提供射频敏感区域的无线通信。我们将其称为RF over Optical (RFoO)。与传统中继系统不同，我们采用射频波段移相波束形成，在将射频信号调制到光波段之前对其初始相位进行调整。作为一个好处，我们能够控制传输信号的能量，将其集中在所需的区域。为了减少开销和器件损耗，我们设计了一种基于预定义波束码本的简化波束形成过程。中继站使用每个预先定义的波束模式发送一系列“训练序列”。移动设备估计这些“训练序列”的信噪比(SNR)，以确定最佳波束方向图，然后通知中继站最佳方向图。通过合理设计波束码本，所提出的系统能够以多波束覆盖更广的服务区域，并且在移动终端获得比非波束形成辐射系统更强的接收功率。与其他波束控制方案相比，该方案易于实现，并允许非常快速的波束变化。我们首先进行了理论分析，然后进行了计算机模拟。仿真结果表明，该系统能有效地提高无线光通信的接收功率，提高误码率。
{"title":"A novel RF signal beamforming scheme over Optical Wireless Communications","authors":"Jiang Liu, Wasinee Noonpakdee, H. Takano, S. Shimamoto","doi":"10.1109/ICSOS.2011.5783695","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783695","url":null,"abstract":"In this paper, we present a novel relay system in which a radio frequency (RF) signal is relayed over optical media to provide wireless communications in RF sensitive areas. We refer to this as RF over Optical (RFoO). Different from conventional relay systems, we adopt RF band phase shift beamforming to adjust the initial phases of the RF signal before modulating it into the optical band. As a benefit, we are able to control the energy of the transmitted signal to concentrate it in desired areas. To reduce overhead and device loss we designed a simplified beamforming process which is based upon a predefined beam codebook. The relay station sends a series of ‘training sequences’ using each pre-defined beam pattern. Mobile devices estimate the Signal-To-Noise (SNR) ratio of these ‘training sequences’ to determine the optimal beam pattern, then informs the relay station of the optimal pattern. By properly designing the beam codebook, the proposed system is capable of providing wider coverage of a service area with multiple beams, and achieving stronger received power at the mobile terminal than non-beamformed radiation system. Compared to other beam control schemes, the proposed scheme is easy to implement and allows for very quick beam changes. We provide a theoretical analysis followed by computer simulation. Our simulation results show that this system can effectively enhance the received power and improve the BER performance of Optical Wireless Communications.","PeriodicalId":107082,"journal":{"name":"2011 International Conference on Space Optical Systems and Applications (ICSOS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132734735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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