| 1. |
- Cabrera Molero, Inés, et al.
(författare)
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Cross-layer adaptation for TCP-based applications in WCDMA systems
- 2005
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Konferensbidrag (refereegranskat)abstract
- In this paper, we consider TCP-based applications over a high bandwidth wireless channel, such as the High-Speed Downlink Packet Access (HSDPA) channel in aWCDMAsystem, in two setups: a nominal one that employs end-to-end TCPReno and a new one that employs Cross-Layer Adaptation (CLA) in the form of Radio Network Feedback (RNF). For theCLAsetup, the Radio Resource Management unit in the Radio Network Controller (RNC) provides a proxy with reports on the radio link bandwidth and the queue level. The proxy transport layer takes appropriate actions on these reports. By doing so, it utilizes the air-interface spectrum more efficiently and keeps the layer-2 queue in the RNCclose a predetermined level. These new control mechanisms are evaluated through ns-2 simulations. In a number of realistic use cases it is shown that the new CLAsetup reduces the time to serve users, and substantially increases the radio link utilization and decreases the required buffer size in the RNC.
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| 2. |
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| 3. |
- Haas, Rüdiger, 1966, et al.
(författare)
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Status of the Onsala Twin Telescopes – One Year After the Inauguration
- 2019
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Ingår i: IVS 2018 General Meeting Proceedings "Global Geodesy and the Role of VGOS – Fundamental to Sustainable Development". ; NASA/CP-2019-219039, s. 17-19
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Konferensbidrag (refereegranskat)abstract
- We briefly describe the status of the Onsala twin telescopes and the experience gained since the official inauguration in May 2017.
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| 4. |
- Haas, Rüdiger, 1966, et al.
(författare)
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Status of the Onsala Twin Telescopes – Two Years After the Inauguration
- 2019
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Ingår i: Proceedings of the 24th European VLBI Group for Geodesy and Astrometry Working Meeting. - 9788441656345 ; , s. 5-9
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Konferensbidrag (refereegranskat)abstract
- We give a brief overview on the status of the Onsala twin telescopes (OTT), two years after their inauguration. The dierent components of the VGOS systems are briefly described, and the development towards routine operations.
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| 5. |
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| 6. |
- Möller, Niels, et al.
(författare)
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Supporting end-to-end applications over HSDPA by cross-layer signalling
- 2007
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Ingår i: IEEE WIRELESS COMMUNICATIONS & NETWORKING CONFERENCE, VOLS 1-9. - NEW YORK : IEEE. - 9781424406586 ; , s. 3858-3863
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Konferensbidrag (refereegranskat)abstract
- A new control structure is proposed to improve user experience of wireless Internet. Information on radio bandwidth and queue length available in the radio network, close to the base station, is used in a proxy that resides between the Internet and the cellular system. The control algorithm in the proxy sets the window size according to event-triggered information on radio bandwidth changes and time-triggered information on the queue length at the wireless link. The mechanism is compared to TCP Reno in two simulation scenarios. The first scenario models a dedicated channel with stepwise changes in the bandwidth, while the second scenario models the High-speed Downlink Shared Channel recently introduced by 3GPP. The proposed mechanism significantly reduces the amount of buffer space needed in the radio network, and it also gives modest improvements to user response time and link utilization. Reduced buffering is particularly beneficial for third-party end-to-end real-time services such as voice, video, and online gaming.
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| 7. |
- Möller, Niels, et al.
(författare)
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Using radio network feedback to improve TCP performance over cellular networks
- 2005
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Ingår i: Proceedings of the 44th IEEE Conference on Decision and Control, and the European Control Conference 2005. - : IEEE. - 0780395689 ; , s. 7434-7439
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Konferensbidrag (refereegranskat)abstract
- A new control structure is proposed to improve user experience of wireless Internet. Information on radio bandwidth and queue length available in the radio network controller (RNC), close to the base station, is used in a proxy that resides between the Internet and the cellular system. The control algorithm in the proxy sets the window size according to event-triggered information on radio bandwidth changes and time-triggered information on the queue length of the RNC. A stability analysis of the hybrid control system is performed. In a number of realistic use cases evaluated in ns-2, the new control structure is compared to a nominal one that employs end-to-end TCP Reno. It is shown that the proposed solution reduces the time to serve users, increases the radio link utilization, and decreases the required buffer size in the RNC.
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| 8. |
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| 9. |
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| 10. |
- Pantaleev, Miroslav, 1970, et al.
(författare)
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Onsala Space Observatory – IVS Technology Development Center
- 2011
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Ingår i: International VLBI Service for Geodesy and Astrometry 2010 Annual Report, edited by D. Behrend and K.Baver. ; :NASA/TP-2011-215880, s. 280-283
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This report briefly describes the technical development relevant for geodetic/astrometric VLBI done during 2010 at the Onsala Space Observatory.
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| 11. |
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| 13. |
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| 14. |
- Risacher, C., et al.
(författare)
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A 279-381 GHz SIS Receiver for the APEX Telescope
- 2006
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Ingår i: Proceedings of the 16th International Symposium on Space Terahertz Technology, Chalmers University of Technology, Gothenburg, Sweden, May 2-4, 2005. ; , s. 432-437
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 15. |
- Tuccari, Gino, et al.
(författare)
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DBBC3 — The new wide-band backend for VLBI
- 2018
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Ingår i: Proceedings of Science. - 1824-8039. ; 344
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Konferensbidrag (refereegranskat)abstract
- The DBBC3 VLBI digital backend is the successor of the most widely adapted digital VLBI backend DBBC2. The DBBC3 offers much wider bandwidth and integrated Ethernet output. Three different firmwares for observing have been implemented until now: Direct Sampling Conversion (DSC), arbitrary selection of bands (OCT), and Digital Down Conversion (DDC). These modes cover all the requirements of the astronomical, VGOS and legacy geodetic VLBI of today, but also of the near future. In addition the DBBC3 offers unsurpassed compatibility to the relatively large number of other existing VLBI backends. A number of DBBC3 systems have been deployed and more are currently under construction, with the number of 4 GHz bands ranging from 2 up to 8 with resulting typical output data-rates from 32 Gbps to 128 Gbps. Laboratory and field tests have been performed.
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| 16. |
- Tuccari, Gino, et al.
(författare)
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DBBC3 Towards the BRAND EVN Receiver
- 2019
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Ingår i: Proceedings of the 24th European VLBI Group for Geodesy and Astrometry Working Meeting. ; , s. 27-30
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Konferensbidrag (refereegranskat)abstract
- The DBBC3 is a flexible VLBI backend and environment that supports a wide range of observational needs via a suite of FPGA firmware types. The hardware can sample up to eight 4 GHz-wide baseband signals and convert to digital streams over multiple 10GE links on fibre. The development team has an ongoing development programme that has enhanced existing modes and introduced new desired modes as user requirements evolve. Three dierent firmware types for observing have been implemented which will be briefly summarised: Direct Sampling Conversion (DSC), arbitrary selection of bands (OCT), Digital Down Conversion (DDC). These modes cover all the requirements of astronomical, VGOS and legacy geodetic VLBI of the present, but also of the near future. At the same time the DBBC3 is an important platform for additional new modes to be implemented for the BRAND receiver. This paper describes the use of the DBBC3 for the receiver development, pointing out which element in the current DBBC3 structure will be part of the BRAND receiver in order to simplify its introduction into the existing VLBI environment at telescopes with a DBBC3 backend.
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| 17. |
- Tuccari, Gino, et al.
(författare)
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New Observing Modes for the DBBC3
- 2019
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Ingår i: International VLBI Service for Geodesy and Astrometry 2018 General Meeting Proceedings “Global Geodesy and the Role of VGOS – Fundamental to Sustainable Development” (NASA/CP–2019-219039). ; NASA/CP-2019-219039, s. 47-49
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Konferensbidrag (refereegranskat)abstract
- The DBBC3 was further enhanced by introducing new modes. Three different firmwares have recently been implemented for observing: Direct Sampling Conversion (DSC), arbitrary selection of bands (OCT), and Digital Down Conversion (DDC). These modes cover all the requirements of astronomical, VGOS, and legacy geodetic VLBI for the time being and the immediate future. In addition, the DBBC3 offers unsurpassed compatibility to the relatively large number of other existing VLBI backends. A number of test observations were performed in the last months to achieve the best performance of the VGOS modes, and similar tests are planned for the EVN network. At the same time the DBBC3 is an important platform for additional new modes to be implemented for the BRAND receiver. Several DBBC3 systems are deployed in the field and more are under construction, with the number of 4-GHz bands ranging from two up to eight with resulting output data rates from 32 Gbps to 128 Gbps.
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