| 1. |
- 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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| 2. |
- 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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| 3. |
- Beckman, Claes, 1962-
(författare)
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Verifying 3G License Coverage Requirements
- 2011
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Ingår i: Advances in Vehicular Networking Technologies. - : InTech. - 9789533072418 ; , s. 339-356
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- 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).
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| 4. |
- Beckman, Claes, 1962-
(författare)
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Wireless communication system for moving vehicles
- 2013
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Patent (populärvet., debatt m.m.)abstract
- 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.
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| 5. |
- Bratu, Vlad-Ioan, et al.
(författare)
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Base Station Antenna Tilt for Load Balancing and Potential use in Self-Optimizating Networks
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The coverage shaping and interference reduction ability of base station antenna tilt are important tools in cellular network optimization. Through tilt changes, the coverage area of a serving cell may also be either reduced or expanded. Therefore, antenna tilt has the potential to be used for load balancing purposes. With the introduction of Self-Organizing Networks (SON) in the mobile communications, this parameter may now be used also in the context of self-optimization, to address the common situation where traffic has an uneven spatial distribution between serving cells. This work gives an overview of base station antennas and antenna tilt. Simulations are performed in order to determine the impact of tilt changes when used for load balancing. The effect of tilt angle, vertical beam width and handover offset are analyzed also. The results show that there is a direct relation between these parameters and the number of users that can be shifted towards neighboring cells. In conclusion, it is found that using antennas with narrow vertical beam widths together with small hand over offsets is an efficient way of performing load balancing but results also in high SIR. Although antenna tilt load balancing can improve the Grade of Service (GoS) in a congested cell, it will also influence the user bit rates and total cell throughput for both the congested cell and the neighbors.
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| 6. |
- Ikram, Amna, et al.
(författare)
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Design and Development of a Multiband Loop Antenna for Cellular Mobile Handsets
- 2011
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Ingår i: IEEE International Workshop on Antenna Technology. - 9781424491339 ; , s. 251-254
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Konferensbidrag (refereegranskat)abstract
- This paper presents the results of the design and characterization of a loop antenna for mobile cellularh andsets. Based on a typical smart phone antenna geometry, a bottom mounted off-ground meanderline loop antennah as been designed, which has the potential to cover the required bands of Long Term Evolution (LTE) US 700MHz, Global System for Mobile communications (GSM) 824-960MHz, Digital Communication System (DCS) 1710-1880 MHz, Personal Communication Services PCS 1850-1990 MHz, Universal Mobile Telecommunications System (UMTS) 1920-2170MHz and LTE EU 2500. The carrier volume of 50*10*5mm3 and ground plane of length 100mm is used. The carrier permittivity εr is 2.66 and loss tangent tanδ is 0.00629 @2.44GHz. Copper is used as a metal part of the antenna having conductivity of 5.8e7 S/m and thickness of 0.1mm. The antenna supports balanced and unbalanced modes for certain frequencies. It is highly efficient in terms of small volumetric size for a given bandwidth of operations. The antenna generates weak near field electric and magnetic fields complying with the standards for the Specific Absorption Rate (SAR) and Hearing Aid Compability (HAC). The impact of body effects on the radiation efficiency has been quantified. The measured results of the prototype are in good agreement with the simulated results.
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| 7. |
- Popovsk, Petar, et al.
(författare)
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EU FP7 INFSO-ICT-317669 METIS, D1.1 Scenarios, requirements and KPIs for 5G mobile and wireless system
- 2013
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This deliverable introduces generic scenarios based on fundamental challenges, and the specific problem description of test cases that will be relevant for beyond future radio access. Specific characteristics of each scenario and each test case include the key assumptions regarding requirements and key performance indicators. In order not to constrain the potential solutions, the requirements are specified from an end-user perspective. The deliverable will not only serve as the guideline for the technical work and system concept design in METIS, but also can serve in external research communities to help to harmonize the work towards the future radio access system including the new generation system of 5G
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| 8. |
- Prasad, Sathyaveer, et al.
(författare)
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Comparison of Four Different Methods to Estimate the Radiated Power from Mobile Phones
- 2010
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Ingår i: Comparison of Four Different Methods to Estimate the Radiated Power from Mobile Phones. - 9781424473052 ; , s. 425-428
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Konferensbidrag (refereegranskat)abstract
- In this paper, the radiated power is estimated for various commercially available mobile phones using the Telia Scattered Field Measurement method (TSFM), In-Network performance estimation and the EMSCAN near field scanner: "Lab-Express". The results are then compared with the radiated power measured using the Satimo Star Gate 64/24 system. Our measurement results suggest that the radiated power measured in the TSFM method correlates to a great extent both with the Star Gate System and the In-network method suggesting that the TSFM method can be used an alternative tool to in-network measurements and also can be used for standard reference measurements provided accuracy and repeatability are accounted according to the standards. However, the results from the Star Gate system were weakly correlated to the results from the Lab-Express suggesting that Lab-Express cannot replace Star Gate System for standard reference measurements but can only serve as a good tool for testing antennas during design and development phases.
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| 9. |
- Ramachandran, Prasadh, et al.
(författare)
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Adaptive penta-band handset antenna with hand effect compensation
- 2012
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Ingår i: IET Microwaves, Antennas & Propagation. - : The Institution of Engineering and Technology. - 1751-8725 .- 1751-8733. ; 6:1, s. 79-86
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Tidskriftsartikel (refereegranskat)abstract
- Theincrease in the number of cellular operating bands and theever-increasing criteria antenna size reduction has pushed the need touse switchable antenna structures. Further, the presence of a handin the close vicinity of the antenna causes deterioration inperformance. The authors present a switchable antenna technique, evaluate theeffect of the human hand on it and discuss anovel method to compensate for the mismatch. A penta-band switchableplanar inverted-F antenna covering 824–960 and 1710–2170 MHz has been usedin this study. The presence of the hand was observedto cause 2.0–6.0 dB loss in efficiency for the low band.Using the proposed extra-ground antenna switching method and the dynamicantenna matching, technique the total efficiency of the antenna canbe improved by 0.5–2.5 dB compared to the mismatched case
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| 10. |
- Tecsor, Irina, et al.
(författare)
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Initial Investigations into the Effects of Mutual Coupling and Architecture of the EISCAT3D array
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- To study the layers of the ionosphere and also the interactions between Earth and Sun, the EISCAT association will build a three dimensional imaging radar: EISCAT3D. The infrastructure of the radar system will include 5 sites with ~10000 antenna elements each.For such arrays, the electromagnetic interaction between radiating elements (coupling effects) and the influence of the ground plane cannot be neglected. In addition, for array applications requiring a large number of elements, a process called thinning is most often applied to remove elements while maintaining much of the same characteristics for the antenna. When the density of components decreases, the coupling in the array will decrease as well.The relative position of elements doesn’t have a great influence on the performance of main beam. It has, however, on the mutual coupling that changes the input impedance of the radiators and the characteristics of the radiation pattern. The challenge is to find a layout where radiating elements will be separated enough for them not to couple but close enough to not disturb the performance of the array antenna.For the purpose of analyzing the performance of the EISCAT3D array, a simulation tool has been developed in Matlab/ Mathematica. In this initial study, thinned arrays with three types of elements: isotropic, half wavelength dipoles and an antenna element designed and simulated at Luleå Technical University are investigated. The latter element was designed with the ambition to meet the rigorous requirements put on the EISCAT3D array when deployed in the Northern part of Scandinavia in order to withstand the harsh environment. The radiation pattern of the single radiator is provided by an EM simulation tool (NEC2) andincludes the mutual coupling to identical elements. Thus, analyzing the radiation pattern of the array with Luleå elements, the mutual coupling effects are taken into consideration.In the simulations an attempt is made to, in a realistic manner and for different scanning angles, calculate performance indicators such as Directivity and Sidelobe level. When the main beam is directed towards the zenith, it was found that between the three elements analyzed, dipoles will result in the lowest directivity and the smallest side lobe level. The directivity of the array with isotropic elements and Luleå elements increases with a regular pattern with increasing number of elements. Between the three types of radiators, Luleå elements will results in the highest average side lobe level and the peak side lobe level gets better than isotropic elements when more than 60% of elements are active.
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