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  • 1. Ahlberg, M.
    et al.
    Lindmark, B.
    Simons, J.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Downlink propagation measurements in the GSM 900 and 1800 MHz bands1999In: IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010), 1999, Vol. 3, p. 1506-1509 vol.3Conference paper (Refereed)
    Abstract [en]

    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.

  • 2.
    Alasali, Mohammad
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    LTE MIMO Performance Measurements on Board Passenger Trains2013Conference paper (Other academic)
    Abstract [en]

    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.

  • 3.
    Alasali, Mohammad
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    LTE MIMO performance measurements on trains2013In: 2013 7th European Conference on Antennas and Propagation (EuCAP), New York: IEEE , 2013, p. 2327-2330Conference paper (Refereed)
    Abstract [en]

    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.

  • 4.
    Alasali, Mohammad
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Karlsson, M.
    Providing internet to trains using MIMO in LTE networks2014In: 2014 International Conference on Connected Vehicles and Expo, ICCVE 2014 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2014, p. 810-814Conference paper (Refereed)
    Abstract [en]

    Providing broadband passenger internet on board trains with continuous connectivity at high speeds and over large rural distances is a challenging issue. One solution to the problem is to use an onboard WiFi network connected to multiple 3G and 4G networks deployed outside the train and aggregate their combined capacity at the IP protocol level. In order to be able to provide the capacity and the data rates that tomorrow’s travelers are expecting, the future 4G standard (LTE-Advance) uses a combination of high order MIMO and carrier aggregation. In this study we use the Swedish company Icomera’s passenger internet system for our investigation. The system provides aggregation of multiple carrier and handover on an IP level. For about 10 years the system has in Sweden primarily been using multiple 3G communication links. However, here we present analysis and onboard measurements of a 2×2 MIMO channel to fast moving train in a live LTE 900 network. The results indicate that MIMO works surprisingly well and it is discussed that by combining 8×8 MIMO with carrier aggregation in future releases of 4G, it may be possible to bring gigabit internet connections to trains.

  • 5.
    Andersson, Daniel
    et al.
    Radarbolaget, Gävle.
    Wallin, Kjell
    Radarbolaget, Gävle.
    Javashvili, Otar
    Högskolan i Gävle, Radio Center Gävle.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    M-Sequence UWB Radar for Industrial Applications2010In: Program of GigaHertz Symposium 2010, March 9-10, at Lund University, 2010Conference paper (Other academic)
    Abstract [en]

    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.

  • 6.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Antenna systems for polarization diversity1997In: Microwave JournalArticle in journal (Refereed)
  • 7.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Antenna-to-Antenna Isolation Measurements1999Report (Other academic)
    Abstract [en]

    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.

  • 8.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Comparison of three methods of evaluating glare.1992In: Acta ophthalmologica, ISSN 0001-639X, Vol. 70, no 1, p. 53-9Article in journal (Refereed)
    Abstract [en]

    A Humphrey Automatic Refractor Model 570 was used to measure the impairment of visual acuity for low contrast optotypes as a result of glare for normal subjects and for subjects with cataracts. This was compared with a direct measure of intraocular light scatter as measured by a compensating technique and with a subjective assessment of glare determined by a questionnaire. Only a weak correlation (r = 0.28) was found between the decrease in low contrast letter acuity and intraocular light scatter. The subjective assessment of glare sensitivity was not correlated with the decrease in low contrast letter acuity, but correlated to some extent (r = 0.55) with the measurement of intraocular light scatter.

  • 9.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Comparison of two glare measurement methods through light scattering modeling.1992In: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 69, no 7, p. 532-7Article in journal (Refereed)
    Abstract [en]

    Two methods used for evaluation of glare in patients with opacities of the ocular media are compared. One is a low contrast letter test and the other is a direct light scattering meter. Theoretical expressions for the measures obtained from the two different glare tests are derived in terms of the point spread function. Measurements on healthy test persons wearing diffusive glasses with known light scattering properties were in good agreement with the theory. Data from 26 cataractous eyes are presented and discussed in light of the theory.

  • 10.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Disputing Viking navigation by polarized skylight.1994In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 33, no 21, p. 4754-5Article in journal (Refereed)
    Abstract [en]

    The widely held notion that the Vikings utilized polarization of skylight on overcast days for navigational purposes is demonstrated to have no scientific basis. The use of polarized skylight for navigation under partly cloudfree skies should be treated with caution and skepticism.

  • 11.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Dual polarised multibeam antenna1999In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 35, no 25, p. 2158-2160Article in journal (Refereed)
    Abstract [en]

    A dual polarised four-beam antenna array for the 1850-1990 MHz frequency band is presented. The polarisations are &plusmn;45&deg; to vertical. The antenna has eight inputs corresponding to two orthogonal polarisations and four beams. The return loss and cross-polar isolation for a single Butler beam exceeds 15 and 22 dB, respectively. The radiation pattern is similar to an ideal Butler pattern and the cross-polarisation level is &lt;-21 dB in the beams

  • 12.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Evaluation of a clinical glare test based on estimation of intraocular light scatter.1991In: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 68, no 11, p. 881-7Article in journal (Refereed)
    Abstract [en]

    A glare test based on psychophysical estimation of intraocular light scatter and using a flickering, annular glare source was evaluated. The parameters determining the accuracy of the test were studied. In particular the influence of background light and flicker frequency were investigated and optimum values for best accuracy were found. Based on these findings a versatile and simple apparatus was constructed. Forty patients with various degrees of cataract were investigated in a clinical study. Patients, who subjectively experience severe glare problems, indeed show high glare values as measured with the apparatus. No obvious relation between visual acuity and glare score was found. In comparison with glare tests using a stationary glare source the use of a flickering glare source is advantageous in terms of sensitivity and accuracy.

  • 13.
    Beckman, Claes
    KTH, School of Electrical Engineering and Computer Science (EECS), Centres, Center for Wireless Systems, Wireless@kth.
    Examining the performance of dul band base station antennas: What progress is being made?1996In: Integrating GSM & DCS 1800: Exploiting the business potential of, London: IIR , 1996Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    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 future 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 basestation antennas, operators are not keen to install more. Therefore, dual-band antennas have gained an increased interest. They would allow the operators to replace two antennas for separate frequency bands with one only, thus, reducing the windload of the towers and perhaps most importantly reducing the cost of installation.

  • 14.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Fiber optic point-source for in vivo measurement of light transmission and scattering in the eye1994In: OphthalmicTechnologies, Proc. SPIE 2126, 324-330 (Societ of Photo-Optical Engineers, Bellingham WA, 1994). / [ed] Societ of Photo-Optical Engineers, Bellingham WA, 1994, Vol. 2126, p. 324-330Conference paper (Refereed)
    Abstract [en]

    A fiber optic point-source was designed for in vivo measurement of light transmission and scattering. The point-source consists of an optical fiber, with a core diameter of about 8 um, mounted in a stainless steel cannula. At the tip of the cannula the entrance face of a 1 mm micro prism is fixed. The hypotenuse face of the prism is coated with aluminum and acts as a mirror reflecting the light out through the exit face. The arrangement allows light fed into the optical fiber to be emitted in a direction perpendicular to the axis of the cannula. The cannula is bent to allow its in vivo introduction into the eye at the posterior pole. The prism is positioned close to the retina along the optical axis of the eye. The light is transmitted through the eye in a reversed beam path (from vitreous towards cornea). In the vitreous, the light source emits within a numerical aperture of about 0. 1 allowing the exiting light to be well confined through the dilated pupil. After careful calibration of the light source, accurate measurements can easily be performed by positioning detector equipment outside the eye. The small size of the point-source (in the range of the eye's resolution) allows measurement of light scatter at both wide and narrow angles. With this intraocular fiber optic technique, it is possible to perform several types of experiments, including measurements of light transmission and scattering, and also studies of fluorescence phenomena in different parts of the ocular media.

  • 15.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Glare and contrast sensitivity before and after Nd: YAG laser capsulotomy.1994In: Acta ophthalmologica, ISSN 0001-639X, Vol. 72, no 1, p. 27-32Article in journal (Refereed)
    Abstract [en]

    The benefits of Nd:YAG laser capsulotomy on visual performance were evaluated in 13 patients with after-cataract following extracapsular cataract extraction. Besides clinical evaluation we measured: visual acuity, letter contrast sensitivity with and without the presence of a circular glare source (glare angle: 8 degrees). Finally, the patients were asked to evaluate their subjective glare problems. In all patients, visual acuity had decreased markedly compared to measurements 2 months after cataract surgery. Before capsulotomy we observed impaired letter contrast sensitivity and increased intraocular light scatter compared to normals. Following capsulotomy, VA and contrast sensitivity both improved by a factor of 2. The subjective glare problems diminished, although most patients showed minor decreases in intraocular light scatter. The limited glare induced loss of letter contrast sensitivity, present before capsulotomy, remained after treatment. Our study indicates that after-cataract impairs resolution and contrast sensitivity without necessarily causing a marked increase in light scatter as measured at a large angle.

  • 16.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Glare measurements before and after cataract surgery.1993In: Acta ophthalmologica, ISSN 0001-639X, Vol. 71, no 4, p. 471-6Article in journal (Refereed)
    Abstract [en]

    The efficacy of cataract surgery in improving visual performance was evaluated in 10 patients by measuring changes in intraocular light scatter, contrast sensitivity and glare induced visual loss. Two different methods were used to estimate these functions before and after cataract extraction with implantation of a monofocal posterior intraocular lens. By one method intraocular light scattering was assessed. By the other, letter contrast sensitivity and glare induced visual loss were determined. Preoperatively most patients had various glare problems, glare induced visual loss and increased intraocular light scatter. Following surgery the letter contrast sensitivity increased by a factor of 3 or more (mean 4.3). The glare problems diminished or disappeared after surgery, although several patients still had increased intraocular light scattering and glare induced visual loss compared to normals. Postoperatively the contrast sensitivity both with and without glare had increased to a level where the glare induced visual loss did not create any visual problems.

  • 17.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Imaging through light scattering eye media: letter identification1994In: Proc.SPIE, Vol. 2079, p. 2079-2079Article in journal (Refereed)
    Abstract [en]

    The influence of intraocular light scatter on letter identification in the absence and presence of glaring light is studied through computer simulations and simple experiments on healthy test subjects wearing diffusive glasses with known light scattering properties. An explicit expression for the point-spread function of a cataractous eye is used to calculate retinal images. For estimating resolution in the calculated images an assumed neural contrast sensitivity function is needed. The function used is derived from measurements by Campbell and Green. Experimental results are in agreement with theory. The analysis shows that visual acuity is quite insensitive even to substantial diffusive scattering provided that glare sources are not present in the field of view. Comparing measurements of ‘letter size’ with measurements of ‘letter contrast’ the latter method is found to measure intraocular light scattering more sensitively.

  • 18. Beckman, Claes
    Implications of Dual Band Functionality on Base Station Antenna Development1997In: Dual Band/Multi Band '97 / [ed] Center for EuroTelecomms, London, 1997Conference paper (Other academic)
    Abstract [en]

    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.

  • 19.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Intraocular light scattering in vision, artistic painting, and photography.1994In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 33, no 21, p. 4749-53Article in journal (Refereed)
    Abstract [en]

    Light scattering in the eye is reviewed, and its influence on vision is discussed in some detail. Isotropic scattering and formation of halos around point sources are described with reference to theory and experiments. Artists usually take intraocularly scattered light into account when painting natural scenes. A method to achieve similar effects in photography by the use of diffraction filters in front of the camera lens is demonstrated. A number of photos that illustrate the effects of such filters are shown.

  • 20.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Letter imaging through light scattering eye media in the absence and presence of glaring light1994In: Vision and its application: OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1994). / [ed] Optical Society of America, Washington, 1994, p. 94-97Conference paper (Refereed)
    Abstract [en]

    In cataractous eyes, part of the incomming light is directly transmitted through the optical media and part is scattered or absorbed by opacities in the lens. Wide angle, diffusively scattered light results in a veiling luminance which mhich mainly reduces

  • 21.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Optical properties of diffractive, bifocal, intraocular lenses.1992In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 31, no 13, p. 2377-84Article in journal (Refereed)
    Abstract [en]

    The resolution of diffractive, bifocal, intraocular lenses was studied with regard to pupil displacement and diameter size through computer simulations, bench measurements, and patient vision-acuity measurements. Good agreement was obtained between these three methods of investigation. In particular, we find that pupil displacements of the order of 1 mm reduce the resolution considerably for these lenses.

  • 22.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Performance analysis of applying up-link estimates in the down-link beamforming using a dual polarized array2000In: VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026), 2000, Vol. 2, p. 690-694 vol.2Conference paper (Refereed)
    Abstract [en]

    Most of the current and future mobile communications systems are frequency duplex systems, i.e. the up- and down-link are separated in frequency. Since the effect of the radio channel is not constant with frequency, this potentially limits the capacity gain using adaptive antennas. We use 150 MHz measurement data to simulate adaptive beamforming in a suburban environment. The information from the up-link at 1741 MHz is used for beamforming at this frequency as well as on the down-link at 1839 MHz. Our results show a reduction in C/I improvement of up to 10 dB between the up- and down-link

  • 23.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Plausibility of assuming ideal arrays for direction of arrival estimation1996In: IEEE Antennas and Propagation Society International Symposium. 1996 Digest, 1996, Vol. 2, p. 1364-1367 vol.2Conference paper (Refereed)
    Abstract [en]

    In order to fulfil the increasing demands on capacity and coverage of mobile communication systems smart or intelligent antennas have been suggested. These antennas increase the spectral efficiency of a wireless system by using arrays of antenna elements to shape RF signals in particular directions. Generally, smart antennas can be divided into two approaches: switched multi-beam and adaptive. Adaptive antennas utilize sophisticated signal processing algorithms to continuously distinguish between the desired signal, multipath and interfering signal as well as to calculate their direction of arrival (DOA). This makes it possible to smoothly track users with main lobes and interferers with nulls and thereby constantly maximizing the SINR (signal-to-interference and noise ratio). The DOA is one of the most important parameter for an adaptive antenna system to estimate. It is also the main subject of this paper. We establish whether or not it is plausible to assume the array to be ideal (which is often assumed in array signal processing theory) when the received signals are actually collected with a physical array consisting of standard folded dipoles. In doing so we first measured the element patterns (or steering vectors) of a twelve element antenna array. The results were then used in array signal processing simulations. The performance of two DOA estimation algorithms, MUSIC and ESPRIT, are studied and compared.

  • 24.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Polarization diversity in CDMA1998In: 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, 1998, Vol. 4, p. 2236-2239 vol.4Conference paper (Refereed)
    Abstract [en]

    Since down-town areas are rapidly becoming littered with antennas, it is of great interest for operators to keep their contribution of antennas to a minimum. Dual polarized antennas may be a solution to reduce the number of antennas, and still obtain a satisfactory antenna diversity gain. However, in order for them to be competitive with space diversity configurations, the diversity gain obtained using dual polarized antennas must be comparable to the that obtained from space diversity. The purpose of this study is to analyse the diversity performance of a DS-CDMA system employing /spl plusmn/45 /spl deg/ dual polarized antennas, for different environments. A system model is presented and analysed.

  • 25.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Remissvar: Från analog till digital marksänd radio: en plan från digitalradiosamordningen (SOU 2014:77)2015Other (Other (popular science, discussion, etc.))
  • 26.
    Beckman, Claes
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS. KTH, School of Electrical Engineering and Computer Science (EECS), Centres, Center for Wireless Systems, Wireless@kth.
    Svar till PTS konsultation inför planerad tilldelning av frekvensutrymme i 2,3- och 3,5 GHz-banden samt tilldelning av frekvensutrymme för lokala tillstånd2019Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    KTH, Skolan för elektroteknik och datavetenskap (EECS) har beretts möjlighet att ge sin syn på PTS ”Konsultation inför planerad tilldelning av frekvensutrymme i 2,3- och 3,5 GHz-banden samt tilldelning av frekvensutrymme för lokala tillstånd”, PTS DNR 18-8496.

    KTH anser att det är olyckligt att PTS frångår principen om teknikneutrala band. Vi förstår att i detta fall finns inga alternativ men råder PTS att arbeta för att framtida spektrumtilldelning sker på teknikneutral basis då inlåsning av frekvensband till specifika tekniker inte bidrar till innovation.

    TDD medger ett mer effektivt utnyttjande av spektrum i fallet då nedlänkstrafik dominerar. Denna vinst måste dock vägas mot det faktum att co-ordinering och synkronisering av och mellan operatörernas nät hämmar konkurrensen. En möjlig framtida lösning är att 3.5 bandet enbart används för nedlänk och att upplänk sker i annat band (tex 1800 bandet). 

    Slutligen så bör spektrumvillkoren vara oberoende av de nu existerande aktörerna. För att även öppna upp för flera och ev nya operatörer så föreslår vi att hela bandet 3,4 - 3,8GHz bjuds ut vid denna auktion.

  • 27.
    Beckman, Claes
    University of Waterloo.
    The influence of increased interocular lightscatter on the contrast in a confocal scanning laserophthalmoscope image1995In: Vision Science and Its Application, Vol. 1 of 1995 OSA Technical Digest Series (Optical Society of America, 1995) / [ed] Optical Society of America, Washington, 1995, Vol. 1, p. 106-109Conference paper (Refereed)
    Abstract [en]

    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.

  • 28.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    The 'light scattering factor'. Importance of stimulus geometry, contrast definition, and adaptation.1995In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 36, no 11, p. 2313-7Article in journal (Refereed)
    Abstract [en]

    PURPOSE: Paulsson and Sjöstrand have suggested that the light scattering factor (LSF) can be estimated by using the equation: LSF = L/E (M2/M1-1). Here L is the space average luminance of the target, E is the illuminance of the glare source, and M2 and M1 are modulation contrast thresholds in the presence and absence of the glare source. To compensate for change of adaptation. Abrahamsson and Sjöstrand later modified the above equation by introducing a correction factor (CF): LSF = L/E ((CF) (M2/M1-1). The purpose of this study is to analyze the validity of the above equations.

    METHODS: The importance of stimulus geometry, contrast definition, background luminance, and glare illumination is studied through theoretical analysis and comparison with earlier studies. Stimulus geometry and contrast definition are studied through optical modeling. Adaptation is modeled according to the laws of Weber and DeVries-Rose.

    RESULTS: The choice of contrast definition may corrupt the result by a factor of 2. At background luminance levels above approximately 10 cd/m2, the Paulsson-Sjöstrand equation agrees well with theory. At lower background levels, the Abrahamsson-Sjöstrand equation is used with correction factors derived from adaptation measurements. Using this equation and earlier published data from glare testing performed at 2 cd/m2, the results are found to be in fair agreement with the light scattering theory.

    CONCLUSIONS: Glare testing using the Paulsson-Sjöstrand equation is found to be valid as long as the measurements are performed at high luminance levels (above 10 cd/m2), with targets of low spatiotemporal frequencies (e.g., 2 cpd and 1 Hz) and with the use of a properly chosen definition of contrast. At lower luminance levels, the Abrahamsson-Sjöstrand equation may be used with well-derived correction factors.

  • 29.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    The performance of polarization diversity antennas at 1800 MHz1997In: IEEE Antennas and Propagation Society International Symposium 1997. Digest, 1997, Vol. 2, p. 1368-1371 vol.2Conference paper (Refereed)
    Abstract [en]

    Cellular radio systems have been in operation since the early 1970s and are experiencing tremendous growth. However, a major problem for cellular systems is the multipath, or short-term fading. One way to combat multipath fading on the uplink is to implement a diversity scheme at the base station. Until recently this was done by using two separate antennas positioned some distance apart from each other. The disadvantage with this method, however, is that the antennas have to be separated by several wavelengths to receive "independently fading" signals. Thus the antenna systems become large. With polarization diversity two antennas are also used but there is no need for any physical separation between them. Instead the two antennas are polarized in two orthogonal polarizations, e.g., horizontal/vertical or /spl plusmn/45 degrees slanted. In a study by Lotse et al. (see IEEE VTS 46th Vehicular Technology Conference Proceedings, vol.3, p.1643-46, 1996) it was found that space diversity yields typically about 1 dB better "diversity gain" than polarization diversity. However, how different antenna parameters affect the results has to our knowledge never been studied. The authors aim to fill this void.

  • 30.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Verifying 3G License Coverage Requirements2011In: Advances in Vehicular Networking Technologies / [ed] Miguel Almeida, InTech , 2011, p. 339-356Chapter in book (Other academic)
    Abstract [en]

    In the beginning of the 21’st century, the 3rd generation mobile phone systems, 3G, were introduced all around the world. In most countries, spectrum for this technology was allocated through some kind of licensing procedure. In Europe, the prevailing approach was to allocatespectrum through auctions, a process which led to a situation where the European operators found themselves committed to pay a staggering 130Bilion Euros for their 3G licenses.However, in most European countries, the fee was not the only obligation put on thelicensee: A coverage, “roll-out” requirement was in many cases also connected to the license(Northstream, 2002). Typically, these coverage requirements required that the licenseescover a certain area at a certain point in time after that the licenses had been awarded.In order for the regulators to verify that the licensees had met the coverage requirement and,hence, complied with the regulation, a method for coverage verification was needed. Suchmethods have therefore since then been developed by several European regulators (e.g. PTS2004; ECC 2007). In this book chapter we describe some general underlying consideration for the verification of radio coverage in UMTS systems and in particular we describe the Swedishmethodology developed by the Swedish Telecom regulator Post & Telestyrelsen (PTS).

  • 31. Beckman, Claes
    Vision and light scattering in the living eye1993In: Light and Color in the Open Air, 13: 28-31, OSA Technocal Digest Series (Optical Society of America, Washington, D.C.,1993 / [ed] Optical Society of America, Washington, 1993, Vol. 13, p. 28-31Conference paper (Refereed)
  • 32.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Wave propagation in curved road tunnels1998In: 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, 1998, Vol. 4, p. 1876-1879 vol.4Conference paper (Refereed)
    Abstract [en]

    In the early seventies much work was done in order to understand the propagation loss of UHF waves in rectangular mine tunnels, using either waveguide methods or image techniques based on geometrical optics (GO). A simple and accurate model is needed for planning the deployment of mobile phone networks. The method presented a simple GO extension to the standard hybrid waveguide solution.

  • 33.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Bergek, Martin
    Wireless communication system for moving vehicles2013Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    A wireless communication system for a moving vehicle, such as trains, is disclosed. The system includes at least one router in the moving vehicle for receiving and transmitting wireless voice communication and data communication to and from a stationary communication server outside the moving vehicle through an exterior mobile network. Further, the system includes at least one femtocell provided within the moving vehicle, and being connected to the router for wireless transferring of wireless voice communication and data communication between mobile terminals within the moving vehicle and the router. The at least one femtocell is controlled by a femtocell controller directly or indirectly connected to the communication server outside the moving vehicle.

  • 34.
    Beckman, Claes
    et al.
    Center for RF-Measurement Technology, University of Gävle.
    Belkow, Elena
    Post och Telestyrelsen.
    Eklund, Lars
    Post och Telestyrelsen.
    Landmark, Urban
    Post och Telestyrelsen.
    Wirdemark, Per
    Canaima International.
    Verifying 3G License Requirements: some Preliminary Swedish Results2008In: The 68th IEEE Vehicular Technology Conference: VTC2008-Fall, IEEE , 2008, p. 1-4Conference paper (Refereed)
    Abstract [en]

    In the year 2000, the Swedish Telecom regulator “Post&Telestyrelsen” (PTS) granted in a “beauty contest” four licenses for operation of 3G mobile networks. Through this process, the licensees committed themselves to cover 8.860.000 inhabitants of the Swedish population. In order to verify the coverage and confirm compliance with the license requirements, PTS, developed a test procedure in close collaboration with the licensees.

    The present paper gives an overview of the considerations behind the design of the test method and presents some preliminary results. Today all Swedish 3G operators comply with the licence requirement and it is concluded that a method for verifying the requirement accepted by the licensees is an important tool for successful licensing of spectrum and fulfilment of licensing obligations.

  • 35. Beckman, Claes
    et al.
    Christian, Braun
    Engblom, Gunnar
    Antenna diversity for mobile telephones1998In: 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, Atlanta, GA, 1998, pp. 2220-2223 vol.4. / [ed] IEEE Antennas and Propagation Society, 1998, Vol. 4, p. 2220-2223Conference paper (Refereed)
    Abstract [en]

    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

  • 36. Beckman, Claes
    et al.
    Curt, Roslund
    Göteborgs Universitet.
    Disputing Viking Navigation by Polarized skylight1993In: Light and Color in the Open Air, OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1993 / [ed] Optical Society of America, Washington DC, 1993, Vol. 13, p. 34-37Conference paper (Refereed)
  • 37.
    Beckman, Claes
    et al.
    University of Gävle.
    Eklund, Lars
    Karlsson, Bo
    Lindmark, Björn
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Ribbenfjärd, David
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Wirdemark, Per
    Verifying 3G licence requirements when every dB is worth a billion2006In: First European Conference on Antennas & Propagation: EuCAP 2006 / [ed] H. Lacoste & L. Ouwehand, 2006, p. 1-4Conference paper (Refereed)
    Abstract [en]

    In the year 2000, the Swedish Telecom regulator: “Post&Telestyrelsen”, PTS, granted in a “beauty contest” four licenses for operations of 3G systems. To verify the coverage and the license requirements, PTS, has developed a test procedure where the field strength of the primary Common Pilot Channel, CPICH, is measured in a drive test. Designing such a test constitutes a number of challenges mainly due to the fact that in 3G the accuracy in the measurement needs to be extremely high since even a small systematic error of ~1dB could in Sweden have the consequence that each operator would have to build an extra +1000 sites at a staggering cost of ~1billion SEK!

    The present paper gives an overview of the considerations behind the design of the test method used for verification of the 3G licence requirements in Sweden.

  • 38.
    Beckman, Claes
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Eriksson, Jon
    Mutual coupling effects on direction of arrival estimation1996In: In Radiovetenskaplig konferens, Luleå, Sweden 1996 / [ed] Lars H Zetterberg, 1996, p. 410-414Conference paper (Refereed)
  • 39.
    Beckman, Claes
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Garcia, J.
    Alfredsson, S.
    Brunström, A.
    On the impact of velocity on the train-to-earth MIMO propagation channel: Statistical observations and qualitative analysis2017In: 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings, IEEE conference proceedings, 2017, p. 1865-1866Conference paper (Refereed)
    Abstract [en]

    We provide measured data collected from 97 trains completing over 7000 journeys in Sweden showing that the throughput over LTE is impacted by train velocity. In order to explain these observations we assume that the underlying causes can be found in the implementation of the MIMO system into LTE Rel. 8 and the diffuse scattering of signals from ground reflections.

  • 40. Beckman, Claes
    et al.
    Jörgen, Thaung
    Göteborgs Universitet.
    Johan, Sjöstrand
    Göteborgs Universitet.
    In vitro Lens Scatter Measurements and Glare Testing1994In: The Association for Research in Vision and Ophthalmology Annual Meeting. Sarasota, Florida, May 1-6, 1994. Abstracts. Investigative Ophthalmology & Visual Science March 1994, Vol.35, 1254-2383., 1994, Vol. 35, p. 1803-Conference paper (Refereed)
  • 41.
    Beckman, Claes
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Karlsson, B.
    The story of Allgon: HF, VHF, cellular and microwave antennas during allmost 60 years2013In: 2013 7th European Conference on Antennas and Propagation (EuCAP), IEEE , 2013, p. 3171-3173Conference paper (Refereed)
    Abstract [en]

    Allgon, 'The Antenna Specialist', was a leading international design house and manufacturer of antennas for almost 60 years. The company was started in Stockholm in 1947 under the name of 'Antennspecialisten', by the Swedish engineer Torbjörn Cramner and his wife Veronica. In 1951 the company moved to Åkersberga north of Stockholm where its main facilities where located until the late 90's. During its life time the company designed and produced antennas for HF, VHF, Cellular and Microwave frequency bands, and for military, emergency, private and cellular radio systems. The company was in 2004 acquired by the US based company Powerwave but still today many of its original antenna designs are in production and many thousands of its base station antennas for mobile networks are still deployed all around the World.

  • 42.
    Beckman, Claes
    et al.
    Högskolan i Gävle.
    Klahr, Stefan
    Ett ödesval för regionen2009In: Gefle Dagblad, ISSN 1103-9302, no 6 februariArticle in journal (Other (popular science, discussion, etc.))
  • 43.
    Beckman, Claes
    et al.
    University of Gävle.
    Lindmark, Björn
    Base station antennas for mobile communications2007In: 2007 IEEE International Symposium on Antennas and Propagation, 2007Conference paper (Other academic)
    Abstract [en]

    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.

  • 44.
    Beckman, Claes
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Lindmark, Björn
    The evolution of base station antennas for mobile communications2007In: International Conference on Electromagnetics in Advanced Applications: ICEAA 07, IEEE conference proceedings, 2007, p. 85-92Conference paper (Refereed)
    Abstract [en]

    This paper gives a general overview of the design of base station antennas for mobile communications. It explains underlying theoretical and practical implementation aspects in mobile communication networks of today and the future. 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 final parts of the paper we give an overview of the underlying theory of diversity and MIMO systems.

  • 45.
    Beckman, Claes
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Lindmark, Björn
    Ahlberg, Mikael
    Dual Band Base Station Antenna Systems1998In: Broad Band Radio Access, Linköping, 1998, p. 69-74, article id 9Conference paper (Other academic)
    Abstract [en]

    An analysis of the possibilities of using dualband antennas in cellular radio is presented. Results from simultaneous measurements at 900 MHz and 1800 MHz are presented and analyzed. Based on the measured results, a dual polarized, dual band base station antenna has been designed. Such an antenna proveides the opportunity to replace a 4 antenna space diversity installation with a single antenna, thereby reducing costs and tower space.

  • 46.
    Beckman, Claes
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Lundgren, L.
    Roos, D.
    Dielectric-loaded circular ridge waveguide applicator for hyperthermia1988In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 1, no 6, p. 221-223Article in journal (Refereed)
    Abstract [en]

    An applicator for intracavitary hyperthermia treatment of cancer has been designed and tested. The applicator is a section of a dielectric-loaded circular ridge waveguide closed at both ends to form a transmission cavity. An aperture in the cavity wall can produce a directed heating of a tumor growing in the wall of a body cavity such as the vagina.

  • 47. Beckman, Claes
    et al.
    Martin, Nilsson
    Jesper, Slettenmark
    Radio Propagation in Curved Road Tunnels1998In: Nordic Radio Symposium on Broadband Radio Access, NRS98 (Saltsjöbaden), 1998., 1998, p. 41-46Conference paper (Other academic)
    Abstract [en]

    This report investigates radio propagation in curved road tunnels at a mobile communications frequency of 925 MHz. This is done by comparing simulations with measurements taken in Norwegian road tunnels. The simulations are based on a simple model derived from geometrical optics and hybrid waveguide modes. The simulations agree well with measurements, indicating that the proposed model is reasonably good.

  • 48.
    Beckman, Claes
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Nilson, Mats
    Remissvar: "Betänkande av Utredningen om radiospektrumanvändningi framtiden – Frekvenser i samhällets tjänst" (SOU 2018:92): Diarie nummer N2019/00192/D2019Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Betänkandet slår fast att frekvensspektrum är en viktig naturresurs som ur samhällets synpunkt måste användas så effektivt som möjligt. När olika användningsmöjligheter står mot varandra blir det svårt att avgöra vilken användning som ger störst samhällsnytta. Detta eftersom teknologi och innehåll för många tjänster är oklar eller tom okänd i det tidsperspektiv som anges. En fortsättning av pågående evolution är dock säkert, gäller också för metodiken runt spektrumallokering. Det är viktigt att spektrumallokering hantereras av en myndighet som i varje tidsskede har kompetens och inflytande för att utföra uppgiften på samma sätt som PTS gör idag.

     

    KTH instämmer med konstaterandet att utvecklingen inom radio och kommunikation för tidsperioden 2027-2047 är omöjlig att förutse. Med detta följer också att metodiken för tilldelning av spektrum också kommer att behöva förändras över tid. Vi kommer att se nya tekniker för adaptivt val av frekvenser och effektiv delning av spektrum. Nya satellitbaserade system är under införande vilket förändrar distribution av ägande och tjänster i en global riktning.

     

    Betänkandet är drivet av antagande om att efterfrågan på spektrum kommer att öka och därmed kommer bristen att öka dramatiskt. Huvudlösningen som förs fram är nya avgifter för att spegla nyttan. Vi inser att nya avgifter kan lösa en del av problemet men ser också att spektrumtilldelning är ett hantverk där många hänsyn måste tas. Helt olika motiv för användning måste vägas mot varandra. I det läget räcker inte en enda optimeringsmetod till, dvs nya avgifter. Vi ser ett stort behov av en myndighet som har nödvändig kompetens för att ta in alla dessa behov och göra de avvägningar som krävs.

     

    Ömmande behov av säkerhet och trygghet i samhället, försvar, vetenskap, är näst intill omöjliga att hantera via en prissättning. De operatörer som idag har stor omsättning inom mobilt Internet har i regel betalt stora summor via auktion och betalar löpande operatörsavgifter i relation till omsättning (PTSFS 2018:06). Att mer eller mindre överföra denna princip på statliga organisationer och på så sätt rotera pengar runt mellan dem känns inte meningsfullt, däremot skall givetvis väl underbyggda hänsyn tas vid varje allokering.

  • 49.
    Beckman, Claes
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Nilsson, Kristoffer
    The Technical and Economic Consequences of Protecting GSM-R in Sweden2016In: 2016 IEEE 83RD VEHICULAR TECHNOLOGY CONFERENCE (VTC SPRING), IEEE, 2016Conference paper (Refereed)
    Abstract [en]

    A number of protection criteria were implemented by the Swedish regulator PTS in order to protect the GSM-R operations in Sweden. In order to protect the GSM-R receivers from interference and blocking, two different constraints were implemented: First, a limitation of the "out-of-band" emissions from the mobile operators' existing base stations operating in the 900MHz band was implemented. Secondly, a limitation of the aggregated power received over the railroad within the operator's spectrum allocation in the 900 band was added. In this study, the background of these protection criteria is presented and their technical and economic consequences estimated. Regarding "out-of-band" emissions from base stations, four alternative protection levels have been investigated: -92, -95, -98 and -107 dBm. It is found that in order to meet these requirements, safety distances of between 280 and 1200m need to be introduced, which means that between 1500 and 2700 base stations would be needed to be taken out of service. In order to avoid blocking, the received power over the embankment from each base station within the public GSM band would also be needed to be limited. The consequences of limiting the received power levels to either -10, -23 or -40 dBm were here investigated. Given the level of blocking protection, it is found that between 1085 and 2330 base stations within the vicinity of the railway track would be affected and possibly needed to be shut down To avoid causing interference, all operators - with the exception of Hi3G - may limit their "out-of-band" emissions by installing filters on the base stations. The cost of such installations is estimated at 50 000 SEK per base station. Depending on the protection level that is applied, the estimated total cost for the mobile operators is between 67 and 113 million SEK (about 12 million Euros). In order to protect the GSM-R receivers from blocking, some 3500 locomotives would need to be equipped with additional filters at a total cost of around 130 million SEK (about 14 million Euros).

  • 50.
    Beckman, Claes
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS.
    Nilsson, Mats
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS.
    Betänkande av Utredningen om radiospektrumanvändning i framtiden – Frekvenser i samhällets tjänst (SOU 2018:92)2019Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    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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