In 1987 Webb and co-workers introduced the Confocal Scanning Laser Ophthalmoscope (CSLO) [1]. Thi... more In 1987 Webb and co-workers introduced the Confocal Scanning Laser Ophthalmoscope (CSLO) [1]. This system is similar to the conventional SLO [2] except that a small aperture is positioned in front of the detector, conjugate to the focus of the illumination spot on the retina (confocal). Analogously to the SLO, the influence of scattered light from points other than the point of illumination is strongly reduced. Additionally an ideal confocal scanning laser microscope has lateral resolution 1.4 times better than a conventional microscope [3]. As the aperture blocks any light scattered from layers or points other than the point of illumination, the depth of focus is drastically decreased, permitting optical tomography.
KTH, har ombetts att ge sin syn pa Betankandet enligt ovan, ert diarienummer N2019/00192/D.Frages... more KTH, har ombetts att ge sin syn pa Betankandet enligt ovan, ert diarienummer N2019/00192/D.Fragestallningarna faller innanfor den utbildning och forskning som bedrivs inom KTH. Skolan har under lan ...
In this document we show results from measurements of the antenna-to-antenna isolation between di... more In this document we show results from measurements of the antenna-to-antenna isolation between different types of base station antenna configurations. The measurements are conducted on antennas for ...
the influence of increased intraocular light scatter on image quality in a confocal scanning lase... more the influence of increased intraocular light scatter on image quality in a confocal scanning laserophthalmoscope (CSLO) is quntified through computer simulations and model eye experiments.
Remissvar: Fran analog till digital marksand radio : en plan fran digitalradiosamordningen (SOU 2... more Remissvar: Fran analog till digital marksand radio : en plan fran digitalradiosamordningen (SOU 2014:77)
Betankandet slar fast att frekvensspektrum ar en viktig naturresurs som ur samhallets synpunkt ma... more Betankandet slar fast att frekvensspektrum ar en viktig naturresurs som ur samhallets synpunkt maste anvandas sa effektivt som mojligt. Nar olika anvandningsmojligheter star mot varandra blir det s ...
Center for EuroTelecomms 2nd Annual Event on Dual Band/Multi Band, October 15, 1997, 1997
The recent growth in cellular communications has rapidly created a need for more radio channels. ... more The recent growth in cellular communications has rapidly created a need for more radio channels. In order to make better use of the available frequency bands new access techniques such as TDMA (Time Division Multiple Access), FDMA (Frequency DMA) and CDMA (Code DMA) have been introduced. Still, the need for new channels is strong and new frequency bands have therefore been allocated for wireless communication systems. These new communication systems, e.g. the European Personal Communication Network (PCN: 1710-1880MHz) and the North American Personal Communication System (PCS: 1850-1990MHz), use frequencies about twice as high as their predecessors (e.g. AMPS: 824-894MHz and GSM: 880-960MHz). However, at a time when our downtown areas already are littered with antennas, operators are not keen to install more. One solution could be to replace existing GSM or AMPS antennas with dual band GSM/PCN or AMPS/PCS. This would reduce the windload of the towers, the number of feeder cables and the whole cost of tower installations. If the dual band antennas were to be dual polarized also, the four antennas today being needed for receiving the PCN and GSM bands in a sector, could actually be replaced by one only.QCR 20181212</p
In the wake of the substantial financial commitments incurred by European and other UMTS network ... more In the wake of the substantial financial commitments incurred by European and other UMTS network operators in the form of licence fees, licensees have turned to network sharing as a means of reducing the capital requirements needed to bring 3G services to market. The reception from European regulators has been mixed, due to concerns that this will inhibit competition, slow buildout, or otherwise result in reduced consumer benefits. The authors believe that the generic product life cycle model provides insights that indicate that network sharing, within an appropriately constructed regulatory framework, is not a threat to vigorous competition in the 3G industry, and in fact is one of the keys to stimulating the development of advanced, ubiquitous, affordable services.
KTH, Skolan for elektroteknik och datavetenskap (EECS) har beretts mojlighet att ge sin syn pa PT... more KTH, Skolan for elektroteknik och datavetenskap (EECS) har beretts mojlighet att ge sin syn pa PTS ”Konsultation infor planerad tilldelning av frekvensutrymme i 2,3- och 3,5 GHz-banden samt tilldel ...
# We report an investigation into theinterference rejection capabilities of a dual antennasystem ... more # We report an investigation into theinterference rejection capabilities of a dual antennasystem on a mobile telephone prototype for the 1800MHz band. The investigation is done by meansof narrowband downlink channel measurements in amicrocellular-likeenvironment. Complex signal samplesare used in order to investigate the interference rejectiongain with di#erent diversity combining schemesand with one and twointerferers present. The resultsshow that there is
Providing cellular voice onboard trains has proven to be a challenging task. The metallic chassis... more Providing cellular voice onboard trains has proven to be a challenging task. The metallic chassis and the energysaving coating on the windows act as a radio shield. In combination with sparsely spaced cellular base stations on rural routes, the coverage onboard inter-city trains is under dimensioned. Since the late 1990s, analog “amplify and forward” radio repeaters have been used extensively to provide coverage of cellular voice onboard trains. However, repeater systems have proven to be both expensive and technically problematic for both trains as well as mobile network operators. In this study, three alternative technologies for providing cellular voice onboard trains are investigated and benchmarked. The technologies under investigation are: circuit-switched voice on GSM and 3G; Voice over IP on LTE (VoLTE); Voice over the onboard Wi-Fi network (VoWiFi). To benchmark these systems against each other, measurements were conducted onboard Swedish X2000 trains, en-route between Stockholm and Gothenburg. In particular we measure: the Availability; the Retainability: Geographical Coverage and Voice quality. Our results show that VoWiFi over the onboard Wi-Fi network outperforms GSM, UMTS as well as VoLTE provided over the onboard repeaters, with equal voice quality as VoLTE but nearly 100% availability and nearly 100% retainability.
In 1987 Webb and co-workers introduced the Confocal Scanning Laser Ophthalmoscope (CSLO) [1]. Thi... more In 1987 Webb and co-workers introduced the Confocal Scanning Laser Ophthalmoscope (CSLO) [1]. This system is similar to the conventional SLO [2] except that a small aperture is positioned in front of the detector, conjugate to the focus of the illumination spot on the retina (confocal). Analogously to the SLO, the influence of scattered light from points other than the point of illumination is strongly reduced. Additionally an ideal confocal scanning laser microscope has lateral resolution 1.4 times better than a conventional microscope [3]. As the aperture blocks any light scattered from layers or points other than the point of illumination, the depth of focus is drastically decreased, permitting optical tomography.
KTH, har ombetts att ge sin syn pa Betankandet enligt ovan, ert diarienummer N2019/00192/D.Frages... more KTH, har ombetts att ge sin syn pa Betankandet enligt ovan, ert diarienummer N2019/00192/D.Fragestallningarna faller innanfor den utbildning och forskning som bedrivs inom KTH. Skolan har under lan ...
In this document we show results from measurements of the antenna-to-antenna isolation between di... more In this document we show results from measurements of the antenna-to-antenna isolation between different types of base station antenna configurations. The measurements are conducted on antennas for ...
the influence of increased intraocular light scatter on image quality in a confocal scanning lase... more the influence of increased intraocular light scatter on image quality in a confocal scanning laserophthalmoscope (CSLO) is quntified through computer simulations and model eye experiments.
Remissvar: Fran analog till digital marksand radio : en plan fran digitalradiosamordningen (SOU 2... more Remissvar: Fran analog till digital marksand radio : en plan fran digitalradiosamordningen (SOU 2014:77)
Betankandet slar fast att frekvensspektrum ar en viktig naturresurs som ur samhallets synpunkt ma... more Betankandet slar fast att frekvensspektrum ar en viktig naturresurs som ur samhallets synpunkt maste anvandas sa effektivt som mojligt. Nar olika anvandningsmojligheter star mot varandra blir det s ...
Center for EuroTelecomms 2nd Annual Event on Dual Band/Multi Band, October 15, 1997, 1997
The recent growth in cellular communications has rapidly created a need for more radio channels. ... more The recent growth in cellular communications has rapidly created a need for more radio channels. In order to make better use of the available frequency bands new access techniques such as TDMA (Time Division Multiple Access), FDMA (Frequency DMA) and CDMA (Code DMA) have been introduced. Still, the need for new channels is strong and new frequency bands have therefore been allocated for wireless communication systems. These new communication systems, e.g. the European Personal Communication Network (PCN: 1710-1880MHz) and the North American Personal Communication System (PCS: 1850-1990MHz), use frequencies about twice as high as their predecessors (e.g. AMPS: 824-894MHz and GSM: 880-960MHz). However, at a time when our downtown areas already are littered with antennas, operators are not keen to install more. One solution could be to replace existing GSM or AMPS antennas with dual band GSM/PCN or AMPS/PCS. This would reduce the windload of the towers, the number of feeder cables and the whole cost of tower installations. If the dual band antennas were to be dual polarized also, the four antennas today being needed for receiving the PCN and GSM bands in a sector, could actually be replaced by one only.QCR 20181212</p
In the wake of the substantial financial commitments incurred by European and other UMTS network ... more In the wake of the substantial financial commitments incurred by European and other UMTS network operators in the form of licence fees, licensees have turned to network sharing as a means of reducing the capital requirements needed to bring 3G services to market. The reception from European regulators has been mixed, due to concerns that this will inhibit competition, slow buildout, or otherwise result in reduced consumer benefits. The authors believe that the generic product life cycle model provides insights that indicate that network sharing, within an appropriately constructed regulatory framework, is not a threat to vigorous competition in the 3G industry, and in fact is one of the keys to stimulating the development of advanced, ubiquitous, affordable services.
KTH, Skolan for elektroteknik och datavetenskap (EECS) har beretts mojlighet att ge sin syn pa PT... more KTH, Skolan for elektroteknik och datavetenskap (EECS) har beretts mojlighet att ge sin syn pa PTS ”Konsultation infor planerad tilldelning av frekvensutrymme i 2,3- och 3,5 GHz-banden samt tilldel ...
# We report an investigation into theinterference rejection capabilities of a dual antennasystem ... more # We report an investigation into theinterference rejection capabilities of a dual antennasystem on a mobile telephone prototype for the 1800MHz band. The investigation is done by meansof narrowband downlink channel measurements in amicrocellular-likeenvironment. Complex signal samplesare used in order to investigate the interference rejectiongain with di#erent diversity combining schemesand with one and twointerferers present. The resultsshow that there is
Providing cellular voice onboard trains has proven to be a challenging task. The metallic chassis... more Providing cellular voice onboard trains has proven to be a challenging task. The metallic chassis and the energysaving coating on the windows act as a radio shield. In combination with sparsely spaced cellular base stations on rural routes, the coverage onboard inter-city trains is under dimensioned. Since the late 1990s, analog “amplify and forward” radio repeaters have been used extensively to provide coverage of cellular voice onboard trains. However, repeater systems have proven to be both expensive and technically problematic for both trains as well as mobile network operators. In this study, three alternative technologies for providing cellular voice onboard trains are investigated and benchmarked. The technologies under investigation are: circuit-switched voice on GSM and 3G; Voice over IP on LTE (VoLTE); Voice over the onboard Wi-Fi network (VoWiFi). To benchmark these systems against each other, measurements were conducted onboard Swedish X2000 trains, en-route between Stockholm and Gothenburg. In particular we measure: the Availability; the Retainability: Geographical Coverage and Voice quality. Our results show that VoWiFi over the onboard Wi-Fi network outperforms GSM, UMTS as well as VoLTE provided over the onboard repeaters, with equal voice quality as VoLTE but nearly 100% availability and nearly 100% retainability.
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Papers by Claes Beckman