Pub Date : 2011-05-11DOI: 10.1109/ICSOS.2011.5783685
A. Puryear, Rui Jin, Edward A. Lee, V. Chan
Clear air atmospheric turbulence causes significant fading for terrestrial-terrestrial and terrestrial-satellite free space optical communication systems. Typically extra link margin is used to assure link availability and reliability, however this extra margin is an inefficient and expensive use of resources. In this paper, we analyze data collected by an experimental system with a single laser transmitter located 250 meters from two coherent receivers. We first use the data to validate the use of a two-state continuous time Markov process to model outage statistics of the diversity system. In the two-state channel model, symbols received during an outage are assumed to be lost, and symbols received during a non-outage are assumed to be received correctly. This channel model can be used to analyze the performance of the transport layer. Next, we use statistical and spectral analysis techniques to create a linear prediction model for signal attenuation for both the single-receiver and diversity systems. The prediction model is an optimal estimator that predicts signal attenuation 1 ms into the future to 1.5 dB accuracy for the single-receiver cases and to 1 dB accuracy for the diversity case. The maximum amount of time the estimator can predict into the future with some confidence is about 5-10 ms. This channel prediction and adaptation can be used to greatly improve the efficiency of free-space optical communication systems in the atmosphere.
{"title":"Experimental analysis of the time dynamics of coherent communication through turbulence: Markovianity and channel prediction","authors":"A. Puryear, Rui Jin, Edward A. Lee, V. Chan","doi":"10.1109/ICSOS.2011.5783685","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783685","url":null,"abstract":"Clear air atmospheric turbulence causes significant fading for terrestrial-terrestrial and terrestrial-satellite free space optical communication systems. Typically extra link margin is used to assure link availability and reliability, however this extra margin is an inefficient and expensive use of resources. In this paper, we analyze data collected by an experimental system with a single laser transmitter located 250 meters from two coherent receivers. We first use the data to validate the use of a two-state continuous time Markov process to model outage statistics of the diversity system. In the two-state channel model, symbols received during an outage are assumed to be lost, and symbols received during a non-outage are assumed to be received correctly. This channel model can be used to analyze the performance of the transport layer. Next, we use statistical and spectral analysis techniques to create a linear prediction model for signal attenuation for both the single-receiver and diversity systems. The prediction model is an optimal estimator that predicts signal attenuation 1 ms into the future to 1.5 dB accuracy for the single-receiver cases and to 1 dB accuracy for the diversity case. The maximum amount of time the estimator can predict into the future with some confidence is about 5-10 ms. This channel prediction and adaptation can be used to greatly improve the efficiency of free-space optical communication systems in the atmosphere.","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":"121127854","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.2011.5783672
M. Gregory, S. Badri-Hoeher
The growing demand on high speed data transmission as well as the bandwidth limitation of microwave (RF) transmission has stimulated the development of free-space optical (FSO) laser communication links during the last years. Making the data transmission reliable is one of the challenging problems that have to be solved to establish a communication system suitable for commercial usage. Optical transmission is highly impacted by different channel conditions, leading from signal damping to turbulence effects due to the atmosphere. In this paper a hybrid RF/FSO maritime channel is investigated. The link distance under investigation is about 14 km. Transmitted data collected during a 6 months measurement campaign is evaluated and theoretically analyzed. The correlation between weather and atmospheric impacts to the large amount of RF and FSO transmission data available, will provide an insight into the capability of estimating channel quality.
{"title":"Characterization of maritime RF/FSO channel","authors":"M. Gregory, S. Badri-Hoeher","doi":"10.1109/ICSOS.2011.5783672","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783672","url":null,"abstract":"The growing demand on high speed data transmission as well as the bandwidth limitation of microwave (RF) transmission has stimulated the development of free-space optical (FSO) laser communication links during the last years. Making the data transmission reliable is one of the challenging problems that have to be solved to establish a communication system suitable for commercial usage. Optical transmission is highly impacted by different channel conditions, leading from signal damping to turbulence effects due to the atmosphere. In this paper a hybrid RF/FSO maritime channel is investigated. The link distance under investigation is about 14 km. Transmitted data collected during a 6 months measurement campaign is evaluated and theoretically analyzed. The correlation between weather and atmospheric impacts to the large amount of RF and FSO transmission data available, will provide an insight into the capability of estimating channel quality.","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":"129120517","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}
Digital coherent methods are anticipated in next - generation optical communications. This paper discusses development of digital coherent optical transceivers for satellite laser communications. We attempt to apply digital filters, which have already shown results in ground optical fiber communications, to phase variations with atmospheric turbulence. For testing purposes, we developed phase modulators, 90-degrees hybrids for orthogonal polarization detection, an automatic optical frequency control circuit (AFC) and a digital signal processing (DSP) board based on field programmable gate array (FPGA). Communication performance is measured with QPSK at a transmission data rate of 12Gbps.
{"title":"Digital coherent optical receiver for satellite laser communication","authors":"Takashi Sasaki, M. Toyoshima, H. Takenaka","doi":"10.2514/6.2011-8065","DOIUrl":"https://doi.org/10.2514/6.2011-8065","url":null,"abstract":"Digital coherent methods are anticipated in next - generation optical communications. This paper discusses development of digital coherent optical transceivers for satellite laser communications. We attempt to apply digital filters, which have already shown results in ground optical fiber communications, to phase variations with atmospheric turbulence. For testing purposes, we developed phase modulators, 90-degrees hybrids for orthogonal polarization detection, an automatic optical frequency control circuit (AFC) and a digital signal processing (DSP) board based on field programmable gate array (FPGA). Communication performance is measured with QPSK at a transmission data rate of 12Gbps.","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":"122428131","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.2011.5783676
C. Rivera, J. Cabrero, P. Munuera, F. Aragón
Calculations based on the k·p perturbation approach have been used to study the properties of GaN-based electroabsorption modulators. The results indicate that optical transitions are dominated by the effect of piezoelectrically-induced electric fields. The measured extinction ratio of non-optimized devices is higher than 3 and 2.5 for modulators operating around 475 nm and 400 nm, respectively. In addition to applied voltage, carrier-induced screening seems an efficient method to drive the modulation.
{"title":"GaN-based technology for MQW modulating retro-reflectors operating in the visible and ultraviolet spectral ranges","authors":"C. Rivera, J. Cabrero, P. Munuera, F. Aragón","doi":"10.1109/ICSOS.2011.5783676","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783676","url":null,"abstract":"Calculations based on the k·p perturbation approach have been used to study the properties of GaN-based electroabsorption modulators. The results indicate that optical transitions are dominated by the effect of piezoelectrically-induced electric fields. The measured extinction ratio of non-optimized devices is higher than 3 and 2.5 for modulators operating around 475 nm and 400 nm, respectively. In addition to applied voltage, carrier-induced screening seems an efficient method to drive the modulation.","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":"129408855","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.2011.5783699
B. Moision, S. Piazzolla
Many photon-counting photo-detectors have the property that they become inoperative for some time after detection event. We say the detector is blocked during this time. Blocking produces losses when using the detector as a photon-counter to detect a communications signal. In this paper, we characterize blocking losses for single detectors and for arrays of detectors. For arrays, we discuss conditions under which the output may be approximated as a Poisson point process, and provide a simple approximation to the blocking loss. We show how to extend the analysis to arrays of non-uniformly illuminated arrays and provide numerical methods to accurately predict count rates for detectors with exponential recovery from the blocked state.
{"title":"Blocking losses on an optical communications link","authors":"B. Moision, S. Piazzolla","doi":"10.1109/ICSOS.2011.5783699","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783699","url":null,"abstract":"Many photon-counting photo-detectors have the property that they become inoperative for some time after detection event. We say the detector is blocked during this time. Blocking produces losses when using the detector as a photon-counter to detect a communications signal. In this paper, we characterize blocking losses for single detectors and for arrays of detectors. For arrays, we discuss conditions under which the output may be approximated as a Poisson point process, and provide a simple approximation to the blocking loss. We show how to extend the analysis to arrays of non-uniformly illuminated arrays and provide numerical methods to accurately predict count rates for detectors with exponential recovery from the blocked state.","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":"117101041","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.2011.5783673
S. Piazzolla, Janet P. Wu, M. Franco, D. Hoppe
A number of criteria need to be considered for site selection of a deep space optical link receiver station. Some of the factors used to identify suitable locations include whether site conditions are favorable in the atmospheric optical channel, geographical convenience of the location, and (possible) existing facilities (e.g. roads, power, communication networks etc.). Recently, NASA/JPL has been conducting studies to evaluate whether the NASA's Deep Space Network (DSN) Goldstone, California site is a viable candidate location for an optical deep space communications downlink station. Some reasons in considering Goldstone are quite evident: 1) the existing facilities would ease the integration of an optical ground station into the DSN; 2) it is conveniently near a NASA center (Jet Propulsion Laboratory or JPL); and 3) it is located in a desert region with possible high Cloud Free Line of Sight (CFLOS) statistics. Evaluating location suitability requires characterization of the atmospheric optical channel of the site, namely atmospheric loss and clear sky turbulence statistics. A suite of sensors has been installed at Goldstone to collect the necessary data to produce these statistics. The instruments include a sun-photometer, seeing monitor, and a dust particle profiler. This work presents initial results based on the data gathered at Goldstone to provide a preliminary assessment of the atmospheric optical channel and its implication on the data throughput for a hypothetical optical deep space mission.
{"title":"Preliminary assessement of the atmospheric optical channel at goldstone (CA)","authors":"S. Piazzolla, Janet P. Wu, M. Franco, D. Hoppe","doi":"10.1109/ICSOS.2011.5783673","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783673","url":null,"abstract":"A number of criteria need to be considered for site selection of a deep space optical link receiver station. Some of the factors used to identify suitable locations include whether site conditions are favorable in the atmospheric optical channel, geographical convenience of the location, and (possible) existing facilities (e.g. roads, power, communication networks etc.). Recently, NASA/JPL has been conducting studies to evaluate whether the NASA's Deep Space Network (DSN) Goldstone, California site is a viable candidate location for an optical deep space communications downlink station. Some reasons in considering Goldstone are quite evident: 1) the existing facilities would ease the integration of an optical ground station into the DSN; 2) it is conveniently near a NASA center (Jet Propulsion Laboratory or JPL); and 3) it is located in a desert region with possible high Cloud Free Line of Sight (CFLOS) statistics. Evaluating location suitability requires characterization of the atmospheric optical channel of the site, namely atmospheric loss and clear sky turbulence statistics. A suite of sensors has been installed at Goldstone to collect the necessary data to produce these statistics. The instruments include a sun-photometer, seeing monitor, and a dust particle profiler. This work presents initial results based on the data gathered at Goldstone to provide a preliminary assessment of the atmospheric optical channel and its implication on the data throughput for a hypothetical optical deep space mission.","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":"126779376","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.2011.5783678
J. Schoolcraft, K. Wilson
Disruption-tolerant networks (DTNs) are groups of network assets connected with a suite of communication protocol technologies designed to mitigate the effects of link delay and disruption. Application of DTN protocols to diverse groups of network resources in multiple sub-networks results in an overlay network-of-networks with autonomous data routing capability. In space environments where delay or disruption is expected, performance of this type of architecture (such as an interplanetary internet) can increase with the inclusion of new communications mediums and techniques. Space-based optical communication links are therefore an excellent building block of space DTN architectures. When compared to traditional radio frequency (RF) communications, optical systems can provide extremely power-efficient and high bandwidth links bridging sub-networks. Because optical links are more susceptible to link disruption and experience the same light-speed delays as RF, optical-enabled DTN architectures can lessen potential drawbacks and maintain the benefits of autonomous optical communications over deep space distances. These environment-driven expectations - link delay and interruption, along with asymmetric data rates - are the purpose of the proof-of-concept experiment outlined herein. In recognizing the potential of these two technologies, we report an initial experiment and characterization of the performance of a DTN-enabled space optical link. The experiment design employs a point-to-point free-space optical link configured to have asymmetric bandwidth. This link connects two networked systems running a DTN protocol implementation designed and written at JPL for use on spacecraft, and further configured for higher bandwidth performance. Comparing baseline data transmission metrics with and without periodic optical link interruptions, the experiment confirmed the DTN protocols' ability to handle real-world unexpected link outages while maintaining capability of reliably delivering data at relatively high rates. Finally, performance characterizations from this data suggest performance optimizations to configuration and protocols for future optical-specific DTN space link scenarios.
{"title":"Experimental characterization of space optical communications with disruption-tolerant network protocols","authors":"J. Schoolcraft, K. Wilson","doi":"10.1109/ICSOS.2011.5783678","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783678","url":null,"abstract":"Disruption-tolerant networks (DTNs) are groups of network assets connected with a suite of communication protocol technologies designed to mitigate the effects of link delay and disruption. Application of DTN protocols to diverse groups of network resources in multiple sub-networks results in an overlay network-of-networks with autonomous data routing capability. In space environments where delay or disruption is expected, performance of this type of architecture (such as an interplanetary internet) can increase with the inclusion of new communications mediums and techniques. Space-based optical communication links are therefore an excellent building block of space DTN architectures. When compared to traditional radio frequency (RF) communications, optical systems can provide extremely power-efficient and high bandwidth links bridging sub-networks. Because optical links are more susceptible to link disruption and experience the same light-speed delays as RF, optical-enabled DTN architectures can lessen potential drawbacks and maintain the benefits of autonomous optical communications over deep space distances. These environment-driven expectations - link delay and interruption, along with asymmetric data rates - are the purpose of the proof-of-concept experiment outlined herein. In recognizing the potential of these two technologies, we report an initial experiment and characterization of the performance of a DTN-enabled space optical link. The experiment design employs a point-to-point free-space optical link configured to have asymmetric bandwidth. This link connects two networked systems running a DTN protocol implementation designed and written at JPL for use on spacecraft, and further configured for higher bandwidth performance. Comparing baseline data transmission metrics with and without periodic optical link interruptions, the experiment confirmed the DTN protocols' ability to handle real-world unexpected link outages while maintaining capability of reliably delivering data at relatively high rates. Finally, performance characterizations from this data suggest performance optimizations to configuration and protocols for future optical-specific DTN space link scenarios.","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":"126531194","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.2011.5783686
J. Gealy, M. Lessard, P. Riley
The results of an exploration regarding the novel use of free-space optics (FSO) between sounding rockets and their sub-payloads are presented. This includes an evaluation of optoelectronic and optical devices against environmental and system level criteria. A preliminary test using available in-house components and bench-top equipment was also performed to determine potential distances and data rates of FSO in this environment. Using a light emitting diode with an optical power output of approximately six milliwatts, and a photomultiplier tube originally purposed for use on the Compton Gamma Ray Observatory, a pulse rate of ten kilohertz was transmitted over a distance of four-hundred meters in-atmosphere. Transmission distance was increased to five-hundred meters using an optical bandpass filter, and nine-hundred meters using a baffle. It is expected that even greater distances and data rates can be achieved in the final design by using more transmitters, each with greater optical power output.
{"title":"Exploration of a free-space optical communications system for sounding rocket sub-payloads","authors":"J. Gealy, M. Lessard, P. Riley","doi":"10.1109/ICSOS.2011.5783686","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783686","url":null,"abstract":"The results of an exploration regarding the novel use of free-space optics (FSO) between sounding rockets and their sub-payloads are presented. This includes an evaluation of optoelectronic and optical devices against environmental and system level criteria. A preliminary test using available in-house components and bench-top equipment was also performed to determine potential distances and data rates of FSO in this environment. Using a light emitting diode with an optical power output of approximately six milliwatts, and a photomultiplier tube originally purposed for use on the Compton Gamma Ray Observatory, a pulse rate of ten kilohertz was transmitted over a distance of four-hundred meters in-atmosphere. Transmission distance was increased to five-hundred meters using an optical bandpass filter, and nine-hundred meters using a baffle. It is expected that even greater distances and data rates can be achieved in the final design by using more transmitters, each with greater optical power output.","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":"121538706","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.2011.5783664
P. Christopher
We estimate worldwide zenith attenuation for 10 micron laser satellite communication systems. The attenuation may be lowered with the aid of switched ground diversity. However, real satellite systems tend to sharply raise the attenuation with low elevation angles and long atmospheric path lengths. Brandon Molniya satellite concepts are expected to give good worldwide laser satellite performance. Four Brandon satellite replacements for geostationary systems are emphasized. The Brandon4 offers relatively low atmospheric attenuation north of 40N, and it allows laser communications to be considered.
{"title":"Satellite laser communication with Brandon orbits","authors":"P. Christopher","doi":"10.1109/ICSOS.2011.5783664","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783664","url":null,"abstract":"We estimate worldwide zenith attenuation for 10 micron laser satellite communication systems. The attenuation may be lowered with the aid of switched ground diversity. However, real satellite systems tend to sharply raise the attenuation with low elevation angles and long atmospheric path lengths. Brandon Molniya satellite concepts are expected to give good worldwide laser satellite performance. Four Brandon satellite replacements for geostationary systems are emphasized. The Brandon4 offers relatively low atmospheric attenuation north of 40N, and it allows laser communications to be considered.","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":"131285305","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.2011.5783692
I. Djordjevic
In order to achieve multi-gigabit transmission (projected for 2020) for the use in interplanetary communications, the usage of large number of time slots in pulse-position modulation (PPM), typically used in deep-space applications, is needed, which imposes stringent requirements on system design and implementation. As an alternative satisfying high-bandwidth demands of future interplanetary communications, while keeping the system cost and power consumption reasonably low, in this invited paper, we describe the use of orbital angular momentum (OAM) as an additional degree of freedom. The OAM is associated with azimuthal phase of the complex electric field. Because OAM eigenstates are orthogonal the can be used as basis functions for multidimensional signaling. The OAM modulation and multiplexing can, therefore, be used, in combination with other degrees of freedom, to solve the high-bandwidth requirements of future deep-space and near-Earth optical communications. The main challenge for OAM deep-space communication represents the link between a spacecraft probe and the Earth station because in the presence of atmospheric turbulence the orthogonality between OAM states is not longer preserved. We will show that in combination with LDPC codes, the OAM-based modulation schemes can operate even under strong atmospheric turbulence regime.
{"title":"LDPC-coded OAM modulation and multiplexing for deep-space and near-Earth optical communications","authors":"I. Djordjevic","doi":"10.1109/ICSOS.2011.5783692","DOIUrl":"https://doi.org/10.1109/ICSOS.2011.5783692","url":null,"abstract":"In order to achieve multi-gigabit transmission (projected for 2020) for the use in interplanetary communications, the usage of large number of time slots in pulse-position modulation (PPM), typically used in deep-space applications, is needed, which imposes stringent requirements on system design and implementation. As an alternative satisfying high-bandwidth demands of future interplanetary communications, while keeping the system cost and power consumption reasonably low, in this invited paper, we describe the use of orbital angular momentum (OAM) as an additional degree of freedom. The OAM is associated with azimuthal phase of the complex electric field. Because OAM eigenstates are orthogonal the can be used as basis functions for multidimensional signaling. The OAM modulation and multiplexing can, therefore, be used, in combination with other degrees of freedom, to solve the high-bandwidth requirements of future deep-space and near-Earth optical communications. The main challenge for OAM deep-space communication represents the link between a spacecraft probe and the Earth station because in the presence of atmospheric turbulence the orthogonality between OAM states is not longer preserved. We will show that in combination with LDPC codes, the OAM-based modulation schemes can operate even under strong atmospheric turbulence regime.","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":"130485246","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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