| 1. |
- Ahlberg, M., et al.
(författare)
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Downlink propagation measurements in the GSM 900 and 1800 MHz bands
- 1999
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Ingår i: IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010). ; , s. 1506-1509 vol.3
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Konferensbidrag (refereegranskat)abstract
- The authors investigate radio propagation in the GSM 900 and 1800 MHz bands in a typical Swedish suburban environment to determine whether or not it is practically feasible to co-site GSM 900 with GSM 1800 systems. They show that propagation in the GSM 1800 band is considerable higher (about 12 dB) than in the old GSM 900. In many cases this difference can be reduced by using dual band sector antennas with 3 dB higher gain at 1800 MHz. However, they also show that in small cells (radius <1000 m) this difference is of little concern and therefore it is possible to co-locate GSM 1800 sites within existing 900 MHz sites as a cost-effective way to increase the system capacity.
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| 2. |
- Alasali, Mohammad, et al.
(författare)
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LTE MIMO Performance Measurements on Board Passenger Trains
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Providing passenger internet on board trains with continuous connectivity at high speeds and over large rural distances is a challenging issue. A frequently used solution to the problem is to use an on board WiFi network connected to the 3G or 4G networks deployed outside the train. In order to be able to provide the capacity and the data rates that tomorrow's business travelers are expecting it has been suggested to use a combination of MIMO and carrier aggregation in the LTE-Advance standard. In this study, we practically investigate the plausibility of using MIMO functionality in an 900 LTE system when the receive antennas are mounted at a train roof about 4m above ground and the base stations antennas are on average placed 2.3km away from the track in towers with an average height of 45m and, hence, most of the time in line of site. It is found that along our test route MIMO is in practice supported by the radio channel at around 70% of the time when the train is travelling with an average speed of 185km/h and the MIMO antennas are mounted 10.5m apart.
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| 3. |
- Andersson, Daniel, et al.
(författare)
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M-Sequence UWB Radar for Industrial Applications
- 2010
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Ingår i: Program of GigaHertz Symposium 2010, March 9-10, at Lund University.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Ultra Wideband Radar has the potential of dramatically improving the control and surveillance of industrial processes in confined areas. An example is the application of UWB radar for surveillance of furnaces for heath treatment of steel billets developed by Radarbolaget in Gävle. In our installation at AB Sandvik Materials Technology, we have shown that by using a non-destructive UWB Radar technique it is possible to visualize in real-time the ongoing process inside the furnace behind a 0.5 m thick ceramic wall. Since the operating temperature inside the furnace is 1200 °C, there is today no other known method capable of visualizing the process for the operator of the furnace. The system is therefore designed to sustain high temperatures and powerful electromagnetic disturbances while performing measurement with wide dynamics and high stability. The design of this radar is based on the idea of transmitting a continuous m-sequence and then detecting the correlated impulse response (see figure below). The wide bandwidth is a requirement for obtaining high spatial accuracy and resolution but puts further requirements on the design of the antennas and the electronics. Our results show that with this technique it is possible to determine the deformation of the steel billets inside the furnace with an accuracy of less than 5 mm. The radar system is also able to detect deformations in the furnace wall The m-sequence radar has many advantages over other UWB radar technologies since it e.g. does not require many analogue components. Its performance is a result of the choice of code length, sampling rate and averaging. However, the resolution is still limited by the impulse response of the analogue antenna (ringing). In this paper system parameters that affect the overall performance of an m-sequence radar are reviewed and means of enhancing its performance are discussed.
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| 4. |
- Beckman, Claes, 1962-
(författare)
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5G and its Implication for Rail
- 2019
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Ingår i: Train Communicatins Systems 2019. - London.
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Konferensbidrag (populärvet., debatt m.m.)
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| 5. |
- Beckman, Claes, 1962-, et al.
(författare)
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Antenna diversity for mobile telephones
- 1998
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Ingår i: <em>IEEE Antennas and Propagation Society International Symposium. 1998 Digest. Antennas: Gateways to the Global Network. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.98CH36</em>, Atlanta, GA, 1998, pp. 2220-2223 vol.4.. ; , s. 2220-2223
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Konferensbidrag (refereegranskat)abstract
- There have been several studies made on new diversity antennas for the mobile telephones. The main idea has been to have a built-in (planar) antenna working together with the conventional external. The purpose of this paper is to examine the concept of diversity further and to design two different concepts, one with two external antennas and one with an external antenna combined with an in-built. For evaluation a MATLAB program developed by the Center for Personkommunikation, CPK, in Aalborg, Denmark, is used. Given the radiation pattern from each antenna and the incoming field distribution from the environment, this program calculates the diversity performance of the system assuming that selection combining is used to combine the signals
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| 6. |
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| 7. |
- Beckman, Claes, 1962-
(författare)
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Antenna-to-Antenna Isolation Measurements
- 1999
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- 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 GSM1800 band. However, since this band is relatively close to the IMT-2000 band it is reasonable to assume similar results for antennas to be used in this band.In this report we present measurement results from antennas with both vertical and slanted dual polarisation, and different horizontal beamwidths. The different antennas are shown in Table 1. The isolation is measured with the antennas positioned for some different configurations.
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| 8. |
- Beckman, Claes, 1962-, et al.
(författare)
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Base station antennas for mobile communications
- 2007
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Ingår i: 2007 IEEE International Symposium on Antennas and Propagation.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This course gives the participants a general overview of the application, implementation and design of current and future base station antennas for mobile communications. It is aimed at microwave, RF- and antenna engineers in the wireless area, but also useful for researchers looking for relevant research topics and system engineers needing a deeper understanding of the antenna component of their system. The course explains underlying theoretical and practical implementation aspects of base station antennas in mobile communication networks of today and the future. The course is divided into three main parts: (i) System Aspects, (ii) BTS Antenna Design, (iii) Diversity and MIMO In the first part the fundamental parameters of a base station antenna are discussed in the context of radio network design. In particular we discuss parameters such as gain, radiation patterns, frequency bands and power handling and put them in the context of cell planning, propagation and capacity. In the second part a general overview of base station antenna design is given. In particular the design aspects of radiators, feed networks and reflectors are discussed. Furthermore, a general discussion of array synthesis for base station antennas is given. In the final part of the course we give an overview of the underlying theory of diversity and MIMO systems. In particular we discuss the requirements that these systems put on the base station antennas in order to be able to deliver the data rates expected from WiMAX and the long term evolution of 3G systems.
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| 9. |
- Beckman, Claes, Professor, 1962-, et al.
(författare)
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Betänkande av Utredningen om radiospektrumanvändning i framtiden – Frekvenser i samhällets tjänst (SOU 2018:92)
- 2019
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Annan publikation (populärvet., debatt m.m.)abstract
- KTH, har ombetts att ge sin syn på Betänkandet enligt ovan, ert diarienummer N2019/00192/D.Frågeställningarna faller innanför den utbildning och forskning som bedrivs inom KTH. Skolan har under lång tid varit ett nav inom utbildning, utveckling och forskning inom radiokommunikation och även hela system för trådlösa tjänster. Ett exempel är ”Wireless@kth”, som i samarbete med industri och myndigheter bedrivit forskning inom området trådlösa system sedan 2001. Forskare inom denna konstellation har berett frågan och lämnar nedanstående yttrande.
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| 10. |
- Beckman, Claes, Professor, 1962-, et al.
(författare)
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Can local 5G networks using local spectrum be used as platform for digitalization of industrial systems and services?
- 2022
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Ingår i: Proceedings 31st European Regional ITS Conference, Gothenburg, Sweden, June 2022.
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Konferensbidrag (refereegranskat)abstract
- Local 5G spectrum licenses has recently attracted a great deal of attention and expectations from both industry and governments all over the world. One reason is the expectation that 5G local industrial networks using local spectrum can be used to support digitalization of industrial processes, and hence increase productivity of industrial use cases. In support of these expectations, governments all over the world have allocated spectrum for local 5G licensing in the 3.5GHz band with various conditions.This paper focuses on local 5G networks for "private" use, these non-public networks are commonly referred to as Non-Public Networks (NPNs). We present results and discussion about implications in three areas: Network capacity and cost for 5G NPN for industrial use; Allocation of local spectrum licenses; Ecosystem analysis of business models and value networks. For the two first areas our analysis indicates that previously identified questions related to radio-interference and co-existence between NPN and operator macro cell networks still seem to be challenging. It is unclear if 5G NPN using Time-Division Duplex (TDD) at the 3.5 GHz band can satisfy performance and operational needs in the field of industrial radio systems. Hence, the value of this type of local 5G licenses need to be further discussed.For the third area and the question “what actor is doing what?” we see a need to look more into solutions where different types of actors cooperate and contribute to different parts of the value network. This is in contrast to what is described in many papers and reports where the assumption is that one type of actor will take care of all or most of the roles.
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