{"title":"可靠的地面无线通信系统,实现更高的比特率","authors":"S. Muhammad, C. Chlestil, E. Leitgeb, M. Gebhart","doi":"10.1109/CONTEL.2005.185942","DOIUrl":null,"url":null,"abstract":"S ignificant advances have been made in the field of Free Space Optics (FSO) over the last few years in response to a need for greater bandwidth and improved communication systems. FSO systems are generally designed as bandwidth and protocol transparent physical layer connections. FSO has mainly evolved as the broadband wireless solution for the \"Last Mile\" connectivity gap throughout the metropolitan networks. At the Institute of Broadband Communications several FSO-systems have been developed and some newer systems are under development currently. In the previous systems, the main emphasis was on using LEDs instead of laser diodes and systems were developed for distances of about 300 ma t as pecific margin of 25 dB/km. Currently, we are developing systems that will provide data rates up-to 1 Gbps, thus providing an opportunity to fully utilize the gigabit optical backbone. Additionally, investigations are being carried out into employing better and well suited modulation and channel coding techniques to enhance the performance of the current systems. Applications of FSO besides the \"last-mile broadband access\" lie in disaster recovery, Tele-medicine, Tele-teaching and in explorations at unusual locations. Free Space Optics (FSO) is a fibreless, laser-driven technology that supports high bandwidth, with easy to install connections for the last mile access. Free Space Optics systems are starting to gain acceptance in the private market place as a solution to replace expensive fibre-optic based solutions. Optical wireless now allows service providers to cost-effectively provide optical band- width for networks, reducing Capex and Opex. Today, the modern internet users are very much inclined towards the high bandwidth demanding applications, like Video on Demand, Video Conferencing, Voice services, etc. and FSO is a well-suited technology to make the high bandwidth of the backbone (Fibre network) available to the end-user. The workgroup for Optical Communications (Optikom) at the Institute of Broadband Communications, Technical University Graz, has carried out research in the field of Free Space Optics (FSO) over a period of ten years. The work included the development of equipment for research purposes and the evaluation of commercially available FSO systems for the climate in Graz (Austria) in co-operation with industrial partners. In this paper, we present some of our earlier developed systems for short range reliable FSO links, and the uti- lization of robust, high rate LEDs in our systems instead of the more common laser diodes for developing cost effective systems. We also highlight the current work we are carrying out into the development of very high-speed Gigabit Free Space Optics Systems, to make the Gigabit backbone accessible for the end-user. An important aspect in FSO developments has always been the influence of the atmosphere and the doubts about the availability and reliability of the FSO links. We are investigating possi- bilities of enhancing the performance of the FSO systems by using more suitable modulation and channel coding techniques, and we present some preliminary work in this regard. The applications of FSO are very diversified and the paper shows some important aspects of the application areas and possibilities of using the technology not only for the last mile access but also in disaster recovery and management.","PeriodicalId":265923,"journal":{"name":"Proceedings of the 8th International Conference on Telecommunications, 2005. ConTEL 2005.","volume":"22 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2005-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"10","resultStr":"{\"title\":\"Reliable terrestrial FSO systems for higher bit rates\",\"authors\":\"S. Muhammad, C. Chlestil, E. Leitgeb, M. Gebhart\",\"doi\":\"10.1109/CONTEL.2005.185942\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"S ignificant advances have been made in the field of Free Space Optics (FSO) over the last few years in response to a need for greater bandwidth and improved communication systems. FSO systems are generally designed as bandwidth and protocol transparent physical layer connections. FSO has mainly evolved as the broadband wireless solution for the \\\"Last Mile\\\" connectivity gap throughout the metropolitan networks. At the Institute of Broadband Communications several FSO-systems have been developed and some newer systems are under development currently. In the previous systems, the main emphasis was on using LEDs instead of laser diodes and systems were developed for distances of about 300 ma t as pecific margin of 25 dB/km. Currently, we are developing systems that will provide data rates up-to 1 Gbps, thus providing an opportunity to fully utilize the gigabit optical backbone. Additionally, investigations are being carried out into employing better and well suited modulation and channel coding techniques to enhance the performance of the current systems. Applications of FSO besides the \\\"last-mile broadband access\\\" lie in disaster recovery, Tele-medicine, Tele-teaching and in explorations at unusual locations. Free Space Optics (FSO) is a fibreless, laser-driven technology that supports high bandwidth, with easy to install connections for the last mile access. Free Space Optics systems are starting to gain acceptance in the private market place as a solution to replace expensive fibre-optic based solutions. Optical wireless now allows service providers to cost-effectively provide optical band- width for networks, reducing Capex and Opex. Today, the modern internet users are very much inclined towards the high bandwidth demanding applications, like Video on Demand, Video Conferencing, Voice services, etc. and FSO is a well-suited technology to make the high bandwidth of the backbone (Fibre network) available to the end-user. The workgroup for Optical Communications (Optikom) at the Institute of Broadband Communications, Technical University Graz, has carried out research in the field of Free Space Optics (FSO) over a period of ten years. The work included the development of equipment for research purposes and the evaluation of commercially available FSO systems for the climate in Graz (Austria) in co-operation with industrial partners. In this paper, we present some of our earlier developed systems for short range reliable FSO links, and the uti- lization of robust, high rate LEDs in our systems instead of the more common laser diodes for developing cost effective systems. We also highlight the current work we are carrying out into the development of very high-speed Gigabit Free Space Optics Systems, to make the Gigabit backbone accessible for the end-user. An important aspect in FSO developments has always been the influence of the atmosphere and the doubts about the availability and reliability of the FSO links. We are investigating possi- bilities of enhancing the performance of the FSO systems by using more suitable modulation and channel coding techniques, and we present some preliminary work in this regard. 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Reliable terrestrial FSO systems for higher bit rates
S ignificant advances have been made in the field of Free Space Optics (FSO) over the last few years in response to a need for greater bandwidth and improved communication systems. FSO systems are generally designed as bandwidth and protocol transparent physical layer connections. FSO has mainly evolved as the broadband wireless solution for the "Last Mile" connectivity gap throughout the metropolitan networks. At the Institute of Broadband Communications several FSO-systems have been developed and some newer systems are under development currently. In the previous systems, the main emphasis was on using LEDs instead of laser diodes and systems were developed for distances of about 300 ma t as pecific margin of 25 dB/km. Currently, we are developing systems that will provide data rates up-to 1 Gbps, thus providing an opportunity to fully utilize the gigabit optical backbone. Additionally, investigations are being carried out into employing better and well suited modulation and channel coding techniques to enhance the performance of the current systems. Applications of FSO besides the "last-mile broadband access" lie in disaster recovery, Tele-medicine, Tele-teaching and in explorations at unusual locations. Free Space Optics (FSO) is a fibreless, laser-driven technology that supports high bandwidth, with easy to install connections for the last mile access. Free Space Optics systems are starting to gain acceptance in the private market place as a solution to replace expensive fibre-optic based solutions. Optical wireless now allows service providers to cost-effectively provide optical band- width for networks, reducing Capex and Opex. Today, the modern internet users are very much inclined towards the high bandwidth demanding applications, like Video on Demand, Video Conferencing, Voice services, etc. and FSO is a well-suited technology to make the high bandwidth of the backbone (Fibre network) available to the end-user. The workgroup for Optical Communications (Optikom) at the Institute of Broadband Communications, Technical University Graz, has carried out research in the field of Free Space Optics (FSO) over a period of ten years. The work included the development of equipment for research purposes and the evaluation of commercially available FSO systems for the climate in Graz (Austria) in co-operation with industrial partners. In this paper, we present some of our earlier developed systems for short range reliable FSO links, and the uti- lization of robust, high rate LEDs in our systems instead of the more common laser diodes for developing cost effective systems. We also highlight the current work we are carrying out into the development of very high-speed Gigabit Free Space Optics Systems, to make the Gigabit backbone accessible for the end-user. An important aspect in FSO developments has always been the influence of the atmosphere and the doubts about the availability and reliability of the FSO links. We are investigating possi- bilities of enhancing the performance of the FSO systems by using more suitable modulation and channel coding techniques, and we present some preliminary work in this regard. The applications of FSO are very diversified and the paper shows some important aspects of the application areas and possibilities of using the technology not only for the last mile access but also in disaster recovery and management.