The growing number of space missions planned in the near future has created a need for a robust communication infrastructure. Such an infrastructure is being developed in the frame of lunar communications by ESA (2023) and NASA (2022) using Delay- and Disruption-Tolerant Networking (DTN) and Bundle Protocol (BP). While their characteristics have made them the standard for future space communications, some areas such as Quality of Service (QoS) or quasi-real-time communications are still to be further developed. This study emphasizes the benefits of using traffic prioritization as a mechanism to enhance QoS and enable quasi-real-time communications between Earth and space. Through a three-state Markov Chain model, the specific channel between Earth and the Moon is modelled realistically, and the impact of traffic prioritization on bundle transmissions is analyzed for several types of transmitting sources. When looking at the amount of high-priority bundles arriving within the 2.5s mark set by ESA for it to be considered quasi-real-time communications, it is shown that there is a significant improvement of up to 23%. This feature is crucial for DTN BP to be able to support the requirements of the upcoming lunar missions, especially those involving extended astronaut stays. Moreover, a priority grid taking into account all the current requirements expressed by both ESA and NASA is presented, as well as implementation proposals to include traffic prioritization in BP as an extension block. Lastly, the need for a common policy for all DTN nodes in order to allow interoperability is highlighted. Therefore, this work contributes to the advancement of DTN BP, bringing it closer to the requirements ahead of us, and paves the way for the needed mechanisms to be implemented.
在不久的将来,越来越多的太空任务计划需要一个强大的通信基础设施。欧空局(2023 年)和美国国家航空航天局(2022 年)正在利用延迟和中断容忍网络(DTN)和捆绑协议(BP)在月球通信框架内开发这样一种基础设施。虽然它们的特点使其成为未来空间通信的标准,但某些领域如服务质量(QoS)或准实时通信仍有待进一步开发。本研究强调了将流量优先级作为一种机制来提高服务质量和实现地球与太空之间准实时通信的好处。通过一个三态马尔可夫链模型,对地球和月球之间的特定信道进行了真实建模,并分析了几类发射源的流量优先级对捆绑传输的影响。在研究欧空局规定的准实时通信 2.5 秒内到达的高优先级捆绑包数量时,结果表明有高达 23% 的显著改善。这一特性对于 DTN BP 能够支持即将到来的月球任务(尤其是涉及宇航员长期停留的任务)的要求至关重要。此外,考虑到欧空局和美国国家航空航天局当前提出的所有要求,还提出了优先级网格,以及将流量优先级作为扩展模块纳入 BP 的实施建议。最后,还强调了为所有 DTN 节点制定通用策略以实现互操作性的必要性。因此,这项工作有助于推动 DTN BP 的发展,使其更接近我们的要求,并为所需机制的实施铺平道路。
{"title":"Enabling Traffic Prioritization for Space Communications Over DTNs","authors":"Teresa Algarra Ulierte;Koojana Kuladinithi;Andreas Timm-Giel;Felix Flentge","doi":"10.1109/JRFID.2024.3415508","DOIUrl":"https://doi.org/10.1109/JRFID.2024.3415508","url":null,"abstract":"The growing number of space missions planned in the near future has created a need for a robust communication infrastructure. Such an infrastructure is being developed in the frame of lunar communications by ESA (2023) and NASA (2022) using Delay- and Disruption-Tolerant Networking (DTN) and Bundle Protocol (BP). While their characteristics have made them the standard for future space communications, some areas such as Quality of Service (QoS) or quasi-real-time communications are still to be further developed. This study emphasizes the benefits of using traffic prioritization as a mechanism to enhance QoS and enable quasi-real-time communications between Earth and space. Through a three-state Markov Chain model, the specific channel between Earth and the Moon is modelled realistically, and the impact of traffic prioritization on bundle transmissions is analyzed for several types of transmitting sources. When looking at the amount of high-priority bundles arriving within the 2.5s mark set by ESA for it to be considered quasi-real-time communications, it is shown that there is a significant improvement of up to 23%. This feature is crucial for DTN BP to be able to support the requirements of the upcoming lunar missions, especially those involving extended astronaut stays. Moreover, a priority grid taking into account all the current requirements expressed by both ESA and NASA is presented, as well as implementation proposals to include traffic prioritization in BP as an extension block. Lastly, the need for a common policy for all DTN nodes in order to allow interoperability is highlighted. Therefore, this work contributes to the advancement of DTN BP, bringing it closer to the requirements ahead of us, and paves the way for the needed mechanisms to be implemented.","PeriodicalId":73291,"journal":{"name":"IEEE journal of radio frequency identification","volume":"8 ","pages":"748-760"},"PeriodicalIF":2.3,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235673","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}
In this paper, we present and deeply characterize a high-speed Optical Wireless Communication (OWC) system designed for use in space applications that operates at 1Gbit/s over a directed optical link for a point-to-point link inside a 3U CubeSat. The OWC transmitter is equipped with a Vertical Cavity Surface Emitting Laser (VCSEL) that emits at 850nm, whilst the receiver uses a PIN Photo-Diode (PD) to detect the modulated signal. We tested the system under extreme conditions including mechanical stresses similar to those experienced during a launch on SpaceX Falcon-9 vehicle, with a realistic spectrum of mechanical vibrations (up to 10G), the temperature variation (between −40 and 80°C), and X-ray irradiation ranges (up to 1Mrad). All of these values were within the expected values (or even much higher) for a Low Earth Orbit (LEO) mission. The results demonstrate that the OWC system can be suitable for use in space applications.
{"title":"High-Speed Optical Wireless System for Extreme Space Conditions","authors":"Giulio Cossu;Lorenzo Gilli;Nicola Vincenti;Ezgi Ertunc;Maurizio Massa;Roberto Dell’Orso;Andrea Moggi;Fabrizio Palla;Ernesto Ciaramella","doi":"10.1109/JRFID.2024.3412413","DOIUrl":"https://doi.org/10.1109/JRFID.2024.3412413","url":null,"abstract":"In this paper, we present and deeply characterize a high-speed Optical Wireless Communication (OWC) system designed for use in space applications that operates at 1Gbit/s over a directed optical link for a point-to-point link inside a 3U CubeSat. The OWC transmitter is equipped with a Vertical Cavity Surface Emitting Laser (VCSEL) that emits at 850nm, whilst the receiver uses a PIN Photo-Diode (PD) to detect the modulated signal. We tested the system under extreme conditions including mechanical stresses similar to those experienced during a launch on SpaceX Falcon-9 vehicle, with a realistic spectrum of mechanical vibrations (up to 10G), the temperature variation (between −40 and 80°C), and X-ray irradiation ranges (up to 1Mrad). All of these values were within the expected values (or even much higher) for a Low Earth Orbit (LEO) mission. The results demonstrate that the OWC system can be suitable for use in space applications.","PeriodicalId":73291,"journal":{"name":"IEEE journal of radio frequency identification","volume":"8 ","pages":"601-608"},"PeriodicalIF":2.3,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141474845","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}
This work presents the design and validation of a compact wireless system, adopting a modular wireless system composed of three co-located antennas operating in the 2.4 GHz band. The system is designed to be exploited for positioning purposes in secondary railway lines where the European railway traffic management system (ERTMS) is not available. An omnidirectional antenna, cross-polarized with respect to the other two, is used for transferring positioning data among the train and intelligent poles placed along the railway, while two directional radiating elements are arranged back-to-back, to perform wagon-to-wagon communication for train integrity purposes. The omnidirectional antenna has a radiation efficiency of 97.8% and a gain of 4.2 dBi, whereas the directive ones have 79.3% and 5.4 dBi, respectively. The data communication is established by using LoRa systems, enabling low-power, long-range communication with acceptable latency for the application purpose. Due to possible adverse environmental conditions, such as presence of dust or ice, a suitable enclosure of the system is designed to be as much as possible electromagnetically transparent. The whole system has been tested both in laboratory environment and on board of the moving train, inside and outside the wagon, demonstrating the successful communication between wagons and with the poles located along the railway. The highest bit error rate monitored was $2.08times 10{^{text {-4}}}$