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  • 1.
    Abbasi, Mahdi
    University of Gävle, Department of Technology and Built Environment.
    Characterization of a 5GHz Modular Radio Frontend for WLAN Based on IEEE 802.11p2008Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The number of vehicles has increased significantly in recent years, which causeshigh density in traffic and further problems like accidents and road congestions.A solution regarding to this problem is vehicle-to-vehicle communication, wherevehicles are able to communicate with their neighboring vehicles even in the absenceof a central base station, to provide safer and more efficient roads and toincrease passenger safety.The goal of this thesis is to investigate basic physical layer parameters of ainter-vehicle communication system, like emission power, spectral emission, errorvector magnitude, guard interval, ramp-up/down time, and third order interceptpoint. I also studied the intelligent transportation system’s channel layout inEurope, how the interference of other systems are working in co-channel and adjacentchannels, and some proposals to use the allocated frequency bands. On theother hand, the fundamentals of OFDM transmission and definitions of OFDMkey parameters in IEEE 802.11p are investigated.The focus of this work is on the measurement of transmitter frontend parametersof a new testbed designed and fabricated in order to be used at inter-vehiclecommunication based on IEEE 802.11p.

  • 2.
    Abrego peris, Iñaki
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Antenna with medical applications for tumour cancer: hyperthermia function2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The idea is to improve or help the treatments that exist in the market in the medical field. Treatments such as mammography or radiotherapy make use of X-rays. X-rays are electromagnetic radiation in a high frequency band, this type of electromagnetic is dangerous to health because ionizing radiation is used, ionized atoms interact with matter. For this reason, in our work we give alternative solution to these treatments without any risk to health. This project consists in the use of non-harmful frequencies such as microwave. In this way, we will make an antenna with medical applications whose frequency range will be between 300 MHz and 30 GHz, specifically between 950MHz and 2.45GHz (medical range). The first step will be the detection of the tumour and classification of this, but our work is about another technique called hyperthermia. This technique consists in increase the temperature with a value of 40-43 degrees in the tumour area. Tumour resistance decreases when heat is applied to this. When combining a treatment with oncologic hyperthermia, the effect of radiotherapy is most effective (between 1.5-5 times). The most important part is study antenna in body tissues characteristics as SAR, depth penetration and antenna size; this theory part is essential to know the best parameters and what case use this. In work development we will choose and design antennas for the different parts of the body in some specific frequencies and choose circular antennas in frequencies of 915 MHz and 1.8 GHz. Finally, we will take measurements about temperature increase with meat and say some conclusions.

  • 3.
    Afzal, Nauman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. tet10nal@student.hig.se.
    Udata, Ramakrishna
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. tet10rua@student.hig.se.
    Designing and measurement of routing module for transceiver system at 3.125GHz2014Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    This report intends to impart a good understanding of routing modules used in modern transceiver systems. The radar system at RadarBolaget AB needed to have a good routing module for its newly designed transceiver antenna. In this report, studies have been done related to two majorly used routing modules in modern electronics industry; Microwave Circulator and RF/Microwave Switch. First off, different characteristics of routing modules are discussed. After having discussed important design parameters, practical design considerations for two routing modules are presented in a profound way. Theoretical knowledge for both of these two devices is presented in the beginning, followed by their practical designs using standard simulation software like HFSS and ADS. The report concludes its findings in a way that at the end of this report, reader becomes acquainted with ample information to be able to choose the best option available among all of the discussed designs. An FET RF Switch is chosen at the end of this project to be used for transceiver system which should be able to satisfy specifications specified by RadarBolaget AB. This project was carried out by two students of Master Program in Electronics/Telecommunications at Högskolan i Gävle in collaboration with RadarBolaget AB, Gävle, Sweden.    

  • 4.
    AHMAD, FAHEEM
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    KAKKERLA, PRAMOD
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    FOCUSING OF UWB RADAR SIGNALS USING TIME REVERSAL2013Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Focusing techniques and detection of targets is usually associated to defense and military use. However in recent past things have moved ahead. Now target detection using UWB radars is being done in many industries and corporations. Radarbolaget AB is one of them; one of their projects uses UWB radars to detect steel strips inside a furnace. This research solves a potential problem of detecting middle steel strip out of total three strip edges which can be seen by radar placed on the front. For better understanding of the reader, existing system and introductory UWB radar principles are discussed. As there can be many solutions to focusing of targets here (steel strip edge detection). Available focusing techniques have been discussed in detail along with the possible physical and simulation setups. Later in the document, detection methods have been proposed. UWB time reversed signal detection is a fairly new method and a very limited research has been done so far. PRBS sequence has been focused on in detection mechanism. Results section show that the pulse of the PRBS works better and produces more promising results rather than a repetitive signal. Time reversal methods for locating the target have been used to find the approximate location of the target. Manual distance calculations from target to the transmitter and receiver have been done. Comparison of actual distance from target to the transmitter is compared with simulation results. Different model simulation setups and their results have proved that using UWB Time reversed signals; a still or moving target can be detected with centimeter window precision.

  • 5.
    Ahmed Mohamed Ahmed, Mazz
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Traffic Model Based Energy Efficient Radio Access Network2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As the concerns about global energy consumption increased the matter of energy consumption in Radio Access Networks (RANs) became an important issue especially with the exponential growth in demanded traffic. This interest of developing innovative technologies to reduce the expected energy consumption by the mobile communication sector was driven by environmental concerns and cost reduction.

    The aim of this thesis is to introduce a new methodology to make the Radio Access Network (RAN) more energy efficient based on jointly the demanded throughput and a realistic traffic profile. Furthermore, to find a metric that quantifies the relation between the Energy Efficiency (EE), Spectrum Efficiency (SE) and demanded throughput.

    The proposed methodology for reducing the energy consumption in the RAN characterizes the offered throughput in order to determine the sufficient energy needed. The manner for reducing the energy consumed by the RAN is simply by switching (OFF/ON) Base Stations (BSs) based on the demanded throughput which introduces an energy efficient RAN.

    The results show a significant reduction in the energy consumption with regard to the demanded traffic. Moreover, it gives a measure of the EE with consideration to the SE which enhances the performance evaluation from an EE point of view during the RAN planning phase.

  • 6.
    Alfaro Zavala, Juan Wilfredo
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Improving Error Performance in Bandwidth-Limited Baseband Channels2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Channel coding has been largely used for the purpose of improving error performance on a communications system. Typical methods based on added redundancy allow for error detection and correction, this improvement however comes at a cost of bandwidth. This thesis focuses on channel coding for the bandwidth-limited channel where no bandwidth expansion is allowed.

    We first discuss the idea of coding for the bandwidth-limited channel as seen from the signal space point of view where the purpose of coding is to maximize the Euclidian distance between constellation points without increasing the total signal power and under the condition that no extra bits can be added. We then see the problem from another angle and identify the tradeoffs related to bandwidth and error performance.

    This thesis intends to find a simple way of achieving an improvement in error performance for the bandwidth-limited channel without the use of lattice codes or trellis-coded modulation.

    The proposed system is based on convolutional coding followed by multilevel transmission. It achieved a coding gain of 2 dB on Eb/No or equivalently, a coding gain of approximately 2.7 dB on SNRnorm without increase in bandwidth. This coding gain is better than that obtained by a more sophisticated lattice code Gosset E8 at the same error rate.

  • 7.
    Al-Tahir, Hibah
    University of Gävle, Department of Technology and Built Environment.
    Multidimensional Measurements: on RF Power Amplifiers2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    Abstract

    In this thesis, a measurement system was set to perform comprehensive measurements on RF power amplifiers. Data obtained from the measurements is then processed mathematically to obtain three dimensional graphs of the basic parameters affected or generated by nonlinearities of the amplifier i.e. gain, efficiency and distortion. Using a class AB amplifier as the DUT, two sets of signals – both swept in power level and frequency - were generated to validate the method, a two-tone signal and a WCDMA signal. The three dimensional plot gives a thorough representation of the behavior of the amplifier in any arbitrary range of spectrum and input level. Sweet spots are consequently easy to detect and analyze. The measurement setup can also yield other three dimensional plots of variations of gain, efficiency or distortion versus frequencies and input levels. Moreover, the measurement tool can be used to plot traditional two dimensional plots such as, input versus gain, frequency versus efficiency etc, making the setup a practical tool for RF amplifiers designers.

    The test signals were generated by computer then sent to a vector signal generator that generates the actual signals fed to the amplifier. The output of the amplifier is fed to a vector signal analyzer then collected by computer to be handled. MATLAB® was used throughout the entire process.

    The distortion considered in the case of the two-tone signals is the third order intermodulation distortion (IM3) whereas Adjacent Channel Power Ratio (ACPR) was considered in the case of WCDMA.

  • 8.
    Amin, Shoaib
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Zenteno, Efrain
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Landin, Per
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Isaksson, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Händel, Peter
    ACCESS Linnaeus Centre, Signal Processing Lab, KTH Royal Institute of Technology.
    Noise Impact on the Identification of DigitalPredistorter Parameters in the Indirect LearningArchitecture2012In: 2012 Swedish Communication Technologies Workshop (Swe-CTW), IEEE conference proceedings, 2012, 36-39 p.Conference paper (Refereed)
    Abstract [en]

    The indirect learning architecture (ILA) is the mostused methodology for the identification of Digital Pre-distorter(DPD) functions for nonlinear systems, particularly for highpower amplifiers. The ILA principle works in black box modelingrelying on the inversion of input and output signals of thenonlinear system, such that the inverse is estimated. This paperpresents the impact of disturbances, such as noise in the DPDidentification. Experiments were performed with a state-of-artDoherty power amplifier intended for base station operationin current telecommunication wireless networks. As expected,a degradation in the performance of the DPD (measured innormalized mean square error (NMSE)) is found in our experiments.However, adjacent channel power ratio (ACPR) canbe a misleading figure of merit showing improvement in theperformance for wrongly estimated DPD functions.

  • 9.
    Andersson, Fredrik
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Utveckling av GIS-applikation för effektivisering av planeringsarbeten för infrastruktur2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Planeringsarbeten för infrastruktur sker ofta med hjälp av speciella programvaror som CAD för att skapa ritningar på kartor över områden där tänkta infrastrukturer skall utvecklas. Som en effektivisering för dessa arbeten handlar denna studie om implementering av en GIS-applikation för att motivera fördelar med GIS och sättet för hantering samt visualisering av geografisk information. En webbapplikation som hanterar baskartor samt överliggande vektorlager för infrastruktur utvecklas, samt även att samma kartdata över infrastrukturen kopplas till en mobilapplikation för att effektivisera eventuella inventeringsarbeten av infrastrukur med hjälp av GPS för att kunna positionera infrastruktur på ett bra sätt. Tekniken bakom utvecklingen bygger på HTML, CSS och JavaScript samt molntjänstlagrin av infrastruktursdata i en geodatabas . GIS-applikationen sammanställer svar på frågor som bevisar hur GIS på ett tillfredställande sätt mycket väl skulle kunna implementeras och användas praktiskt i ett utvecklingsarbete för infrastruktur i dagens morderna samhälle. 

  • 10.
    Björsell, Niclas
    et al.
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Nader, Charles
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. Signal Processing Lab, Royal Institute of Technology, Stockholm, Sweden.
    Händel, Peter
    Signal Processing Lab, Royal Institute of Technology, Stockholm, Sweden.
    Multi-tone design for out-of-band characterization of nonlinear RF modules using harmonic sampling2010In: 2010 IEEE International Instrumentation and Measurement Technology Conference, I2MTC 2010: Proceedings, Piscataway, NJ: IEEE Service Center , 2010, 620-623 p., 5488231Conference paper (Refereed)
    Abstract [en]

    In this paper we evaluate the generation of a multi-tone set for characterizing the behavior of nonlinear radio frequency (RF) modules in its out-of-band when harmonic sampling is used as digitizer. The purpose is to provide the reader with a tool to select proper frequencies and record length for a given application and test-bed. The method is based on simulations and the use of Sidon sequences. The proposed method is applicable to sparse discrete frequency multi-tones.

  • 11.
    Björsell, Niclas
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Van Moer, Wendy
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Adding errors to reduce the PAPR and BER of OFDM-based transmissions2013In: 2013 IEEE International Instrumentation and Measurement Technology Conference (I2MTC 2013), New York: IEEE , 2013, 743-746 p.Conference paper (Refereed)
    Abstract [en]

    When transmitting signals, one of the most important issues is to keep the transmission errors as low as possible. Or in other words, to obtain a reliable transmission link, the bit-error-rate (BER) should be kept within certain limits. However, the probability of transmission errors strongly depends on the signal-to-noise ratio (SNR) of the transmitted signals. Hence, the power amplifier plays a key role in the sender part: the more power, the higher the SNR, the lower the probability of transmission errors. Unfortunately, this is a too simple vision.

    One should take care to keep the peak-to-average power ratio (PAPR) of the transmitted signal low in order not to push the power amplifier into its nonlinear operation region. Classical techniques use clipping or backing-off the input signal to reduce the PAPR of the transmitted signal. However, these techniques have a negative influence on the SNR and hence on the BER.

    In this paper, we present a technique to reduce the PAPR of the transmitted signals and hence to reduce the BER, by introducing errors into Orthogonal Frequency Division Multiplexing (OFDM) signals in a controlled way. Channel coding will be used to compensate for the introduced errors.

  • 12.
    Chani Cahuana, Jessica Adaid
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Pulse Modulated Transmitter Architectures: Carrier Bursting2012Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
  • 13.
    Condo Neira, Edith Graciela
    University of Gävle, Department of Technology and Built Environment.
    Multidimensional Measurements on RF Power Amplifiers2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    Measurements are important to specify and verify properties for components, modules and systems. The specifications for a certain figure of merit are usually given in a numerical value or a two dimensional plot. However, there are some devices, like power amplifiers with certain figure of merits that depends on two or more working conditions, requiring a three dimensional plot.

    This thesis presents a measurement method including graphical user interface of three parameters gain, efficiency and distortion when two-tone or WCDMA signals are used as an input to the PA.

  • 14.
    cui, qiaofeng
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Suppression of impulsive noise in wireless communication2014Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    This report intends to verify the possibility that the FastICA algorithm could be applied to the GPS system to eliminate the impulsive noise from the receiver end. As the impulsive noise is so unpredictable in its pattern and of great energy level to swallow the signal we need, traditional signal selection methods exhibit no much use in dealing with this problem. Blind Source Separation seems to be a good way to solve this, but most of the other BSS algorithms beside FastICA showed more or less degrees of dependency on the pattern of the noise. In this thesis, the basic mathematic modelling of this advanced algorithm, along with the principles of the commonly used fast independent component analysis (fastICA) based on fixed-point algorithm are discussed. To verify that this method is useful under industrial use environment to remove the impulsive noises from digital BPSK modulated signals, an observation signal mixed with additive impulsive noise is generated and separated by fastICA method. And in the last part of the thesis, the fastICA algorithm is applied to the GPS receiver modeled in the SoftGNSS project and verified to be effective in industrial applications. The results have been analyzed.

  • 15.
    Dahal, Robi
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Mercan, Demet
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Design and performance analysis of purely textile antenna for                                                   wireless applications2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis work is concerned with the design and performance analysis of purely textile antenna for wireless applications. The materials used for radiating element, ground plane and dielectric substrate are purely textile. Two types of antennas are studied, the microstrip patch antenna and RFID tag antenna. Each type of antenna is designed and fabricated using two different conductive textile materials as radiating element.

     The radiating element and ground plane of conventional printed antenna is manufactured with the metal plating on a solid dielectric substrate. The radiating element which is used in this thesis work has different characteristics as compared to printed antenna because it is made of conductive textile material which is less conductive than metal and elastic in nature. Each conductive textile material has different surface resistivity. The study has been made to analyze the effect on gain and radiation efficiency of the antenna when different conductive textile material is used as the radiating element. The measured results of the fabricated antennas present the full potential of conductive textile materials to be used as an antenna.

  • 16.
    Dolz, Jose
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Marzal, Silvia
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    A new Propagation Model for Industrial Environments2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis is a project carried out at the “Centre for RF measurements Technology“at the University of Gävle. The first aim was basically the characterization of different industrial indoor environments to get a model that describes dispersive features of each environment.

     

    The results of previous measurements campaign on three industrial environments as steel mill, storage paper and industrial process mill are used. Also new Power Delay Profile (PDP) on corridor and laboratory has been developed.

     

    Measurements for three frequency bands are done (183-683 MHz, 1640-2140MHz and 2200-2700MHz) and for line-of-sight (LOS) and non-line-of-sight (NLOS) industrial and laboratory scenaries cases are presented.

     

    All these models have been compared with other existing models as Saleh-Valenzuela Model, Two Cluster Model and Indoor Power Delay Profile Model (IPDP Model) and fit-line, typical deviation are shown.

     

    Finally we present a study of the different systems used in the industry and the best suited system to the conditions is chosen.

     

  • 17.
    Englund, Johan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Determining suitability of the IEEE1609 standard for PRT systems2010Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Personal Rapid Transit systems have high demands on its reliability and security. Many of the fundamental functions needed by a PRT system can be provided by a wireless radio communication link. The goal of this thesis is to determine if the emerging radio standard for intelligent transportation systems is suitable for providing some of the needed functions. The emphasis of this work is to understand the features of the standard that are important for a PRT system and to verify them with simulation.

  • 18.
    Feng, Tianyang
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Studying Noise Contributions in Nonlinear Vector Network Analyzer (NVNA) Measurements2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Noise contribution in nonlinear systems is very different from that in linear systems. The noise effects in nonlinear systems can be complicated and not obvious to predict. In this thesis, the focus was on the noise contribution in nonlinear systems when measuring with the nonlinear vector network analyzer (NVNA). An additional noise source together with a single sinewave signal was fed into the input of the amplifier and the performance was studied. The input power of the amplifier is considered to be the sum of the noise power and the signal power. The variation of the 1 dB compression point and the third order interception point as functions of the added noise power were studied. From the measured results in this thesis, the 1 dB compression point referred to the output power will decrease when increasing the added noise power at the input of the amplifier. The contribution of the added noise to the 1 dB compression point of an amplifier is considered dual: with the added noise the linear regression lines of the AM/AM curves are changed, and due to hard clipping the useful output power is reduced. As a result of those two effects, the added noise made the compression start at a lower power level. When the added noise reaches a certain level, the 1 dB compression point is hard to measure.

    Thus when performing nonlinear measurements, the noise effects should be taken into considerations and further studies are required to get better understanding of the system’s behavior in noisy environment.

  • 19.
    Ferrer Coll, Javier
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. KTH, Radio Systems Laboratory (RS Lab).
    Channel Characterization and Wireless Communication Performance in Industrial Environments2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The demand for wireless communication systems in industry has grown in recent years. Industrial wireless communications open up a number of new possibilities for highly flexible and efficient automation solutions. However, a good part of the industry refuses to deploy wireless solutions products due to the high reliability requirements in industrial communications that are not achieved by actual wireless systems. Industrial environments have particular characteristics that differ from typical indoor environments such as office or residential environments. The metallic structure and building dimensions result in time dispersion in the received signal. Moreover, electrical motors, vehicles and repair work are sources of electromagnetic interference (EMI) that have direct implications on the performance of wireless communication links. These degradations can reduce the reliability of communications, increasingthe risk of material and personal incidents. Characterizing the sources of degradations in different industrial environments and improving the performance of wireless communication systems by implementing spatial diversity and EMI mitigation techniques are the main goals of this thesis work.

    Industrial environments are generally considered to be environments with a significant number of metallic elements and EMI sources. However, with the penetration of wireless communication in industrial environments, we realize that not all industrial environments follow this rule of thumb. In fact, we find a wide range of industrial environments with diverse propagation characteristics and degradation sources. To improve the reliability of wireless communication systems in industrial environments, proper radio channel characterization is needed for each environment. This thesis explores a variety of industrial environments and attempts to characterize the sources of degradation by extracting representative channel parameters such as time dispersion, path loss and electromagnetic interference. The result of this characterization provides an industrial environment classification with respect to time dispersion and EMI levels, showing the diverse behavior of propagation channels in industry.

    The performance of wireless systems in industrial environments can be improved by introducing diversity in the received signal. This can be accomplished by exploiting the spatial diversity offered when multiple antennas are employed at the transmitter with the possibility of using one or more antennas at the receiver. For maximum diversity gain, a proper separation between the different antennas is needed. However, this separation could be a limiting factor in industrial environments with confined spaces. This thesis investigates the implication of antenna separation on system performance and discusses the benefits of spatial diversity in industrial environments with high time dispersion conditions where multiple antennas with short antenna separations can be employed.

    To ensure reliable wireless communication in industrial environments, all types of electromagnetic interference should be mitigated. The mitigation of EMI requires interference detection and subsequent interference suppression.This thesis looks at impulsive noise detection and suppression techniques for orthogonal frequency division multiplexing (OFDM) based on wide-band communication systems in AWGN and multi-path fading channels. For this,a receiver structure with cooperative detection and suppression blocks is proposed.This thesis also investigates the performance of the proposed receiver structure for diverse statistical properties of the transmitted signal and electromagnetic interference.

  • 20.
    Ferrer Coll, Javier
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. University of Gävle, Center for RF Measurement Technologies. KTH, KTH Center för Trådlösa System, Wireless@kth.
    RF Channel Characterization in Industrial, Hospital and Home Environments2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The rapid development of electronic components has resulted in the emergence of newmobile applications targeted at industry and hospital sectors. Moreover, a lack of availablewireless frequencies as result of the growth of wireless systems is becoming a problem.In this thesis we characterize industrial and hospital environments in order to provide theknowledge necessary to asses present and future development of critical wireless applications.Furthermore, we investigate the possibility of using TV white space by analysingthe interference from secondary to primary user in home environments.

    Some of the wireless solutions used in industries and hospitals come directly fromsystems designed for home or office, such asWLAN and Bluetooth. These systems are notprepared to handle problems associated with interference of impulsive character found inindustrial processes and electrical systems.

    Typically, industrial environments have been classified as reflective environments dueto the metallic structure present in the buildings. In this thesis, we demonstrate that althoughthis may be generally true, some locations in the industry may have special propertieswith wave propagation characteristics in the opposite direction. Stored materials canabsorb wireless signals, resulting in a coverage problem. From the measurement campaignwe are able to distinguish three main classes of indoor environments (highly reflective,medium reflective and low reflective) with different propagation characteristics.

    Improving spectrum efficiency can be a solution to the growing demand for wirelessservices and can increase a system’s robustness against interference, particularly in criticalapplications in industrial and hospital environments. One improvement in spectrum efficiencycan be for secondary consumers to reuse unassigned portions of the TV spectrum ata specific time and geographical location. This thesis studies the effect of inserting whitespace devices in the TV broadcast spectrum. Note that any new model must state the maximumpower allocated to secondary users to avoid harmful interference with the primarysignal.

    The content of this thesis is divided into three parts. The first part is the most comprehensiveand addresses electromagnetic interference and multipath characterization ofindustrial environments. In this part, we have developed a method for channel characterizationfor complex electromagnetic environments and have produced results from differentindustrial environments. The second part presents a preliminary study that characterizesthe electromagnetic interference in a hospital environment. The third part is a study ofsecondary users reusing the TV white spaces.

  • 21.
    Ferrer-Coll, Javier
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. School of ICT, KTH Royal Institute of Technology, Stockholm, Sweden .
    Slimane, Ben
    School of ICT, KTH Royal Institute of Technology, Stockholm, Sweden .
    Chilo, José
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Stenumgaard, Peter
    School of ICT, KTH Royal Institute of Technology, Stockholm, Sweden; Department of Electrical Engineering (ISY), Linköping University, Linköping, Sweden .
    Detection and Suppression of Impulsive Noise in OFDM Receiver2015In: Wireless personal communications, ISSN 0929-6212, E-ISSN 1572-834X, Vol. 85, no 4, 2245-2259 p.Article in journal (Refereed)
    Abstract [en]

    In recent years, the use of wireless systems in industrial applications has experienced spectacular growth. Unfortunately, industrial environments often present impulsive noise which degrades the reliability of wireless systems. OFDM is an enhanced technology used in industrial communication to monitor the work and movement of employees using high quality video. However, OFDM is sensitive to high amplitude impulsive noise because the noise energy spreads among all OFDM sub-carriers. This paper proposes a receiver structure consisting of two stages: a detector stage combining Fisher’s Quadratic discriminant and Gaussian Hypothesis techniques, and a suppression stage optimized by setting well defined thresholds. The receiver structure has been tested by simulations and measurements providing an increment in the probability of detection and improving the system performance.

  • 22.
    Ferrer-Coll, Javier
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Ängskog, Per
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Elofsson, Carl
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Chilo, José
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Stenumgaard, Peter
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. FOI.
    Antenna Cross Correlation and Ricean K-Factor Measurements in Indoor Industrial Environments at 433 and 868 MHz2013In: Wireless personal communications, ISSN 0929-6212, E-ISSN 1572-834X, Vol. 73, no 3, 587-593 p.Article in journal (Refereed)
    Abstract [en]

    The Ricean K-factor and antenna diversity properties for indoor industrial environments have been characterized for 433 and 868 MHz. The high amount of metallic structures gives a multipath environment that heavily differs from other environments e.g. indoor office environments. The results show that low correlation between receiving antennas can be achieved for shorter antenna distances than in other environments.

  • 23.
    Flattery, Kyle
    et al.
    Indiana University - Purdue University Fort Wayne, Fort Wayne, USA.
    Amin, Shoaib
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. ACCESS Linnaeus Centre, Signal Processing Dept, KTH Royal Institute of Technology, Stockholm, Sweden.
    Mahamat, Yaya
    Indiana University - Purdue University Fort Wayne, Fort Wayne, USA..
    Eroglu, Abdullah
    Indiana University - Purdue University Fort Wayne, Fort Wayne, USA..
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    High Power Combiner/Divider Design for Dual Band RF Power Amplifiers2015In: Proceedings of the 2015 International Conference on Electromagnetics in Advanced Applications: ICEAA 2015, IEEE Press, 2015, 1036-1039 p.Conference paper (Refereed)
    Abstract [en]

    Design of low loss with an enhanced thermal profile power divider/combiner for high power dual-band Radio Frequency (RF) power amplifier applications is given. The practical implementation, low loss and substrate characteristics make this type of combiner ideal for high power microwave applications. The combiner operational frequencies are chosen to operate at 900 MHz and 2.14 GHz, which are common frequencies for concurrent dual band RF power amplifiers. The analytical results are verified with simulation results for various cases and agreement has been observed on all of them.

  • 24.
    Fraile, F
    et al.
    Universidad Politécnica de Valencia.
    Nader, Charles
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. University of Gävle, Center for RF Measurement Technologies.
    Guerri, J. C.
    Universidad Politécnica de Valencia.
    Björsell, Niclas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. University of Gävle, Center for RF Measurement Technologies.
    On the reuse of DVB-T transmitter infrastructure for DVB-T22011Conference paper (Refereed)
    Abstract [en]

    The new DVB-T2 standard was specifically designed to allow the reuse of DVB-T infrastructure if required. This paper presents measurement results that verify the correct performance of a commercial DVB Power Amplifier with DVB-T2 waveforms. Furthermore, the paper includes configuration guidelines and performance evaluation of the Tone Reservation PAPR reduction algorithm included in the DVB-T2 standard. PAPR reduction is key technology when reusing DVB-T amplifiers for DVB-T2 transmissions without penalizing amplifier efficiency.

  • 25.
    Fritzin, Jonas
    et al.
    Linköping University.
    Jung, Ylva
    Linköping University.
    Landin, Per Niklas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. University of Gävle, Center for RF Measurement Technologies.
    Händel, Peter
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Enqvist, Martin
    Linköping University.
    Alvandpour, Atila
    Linköping University.
    Phase predistortion of a class-D outphasing RF amplifier in 90 nm CMOS2011In: IEEE Transactions on Circuits and Systems - II - Express Briefs, ISSN 1549-7747, Vol. 58, no 10, 642-646 p.Article in journal (Refereed)
    Abstract [en]

    This brief presents a behavioral model structure and5a model-based phase-only predistortion method that are suitable for outphasing RF amplifiers. The predistortion method is based on a model of the amplifier with a constant gain factor and phase rotation for each outphasing signal, and a predistorter with phase rotation only. The method has been used for EDGE and wide-band code-division multiple-access (WCDMA) signals applied to a Class-D outphasing RF amplifier with an on-chip transformer used for power combining in 90-nm CMOS. The measured peak power at 2 GHz was +10.3 dBm with a drain efficiency and power-added efficiency of 39% and 33%, respectively. For an EDGE 8 phase-shift-keying (8-PSK) signal with a phase error of 3 degrees between the two input outphasing signals, the measured power at 400 kHz offset was −65.9 dB with predistortion, compared with −53.5 dB without predistortion. For a WCDMA signal with the same phase error between the input signals, the measured adjacent channel leakage ratio at 5-MHz offset was -50.2 dBc with predistortion, compared with -38.0 without predistortion.

  • 26.
    Fu, Xubo
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Characterization of NI-USRP System2014Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Nowadays the rapid developments of wireless communication technologies there are more and more

    ways to look into the RF measurements and designs in detail such as Universal Software Radio

    Peripheral(USRP) from LabVIEW, Advance Design System(ADS),etc.Moreover a lack of

    measurements what compared with different digital modulation schemes is becoming a problem. In

    this thesis by building the simulations of communication system in NI-USRP system and measuring

    the results then compare with the different PSK system in order to give a deeper insight of this new

    software of USRP from LabVIEW. and in the end analyze bit error rate varus signal to noise ratio

    from the PSK system.

    To get the characterizations of NI-USRP system the first step is to build multiple simulations such as

    FM receiver, PSK wireless communication systems. By performing the FM receiver is to analyze the

    quality of the receiving and baseband FM signal. And from the simulation of different PSK

    communications through the analysis of the performance of BPSK,QPSK,OQPSK and compared with

    bit error rate it could give an insight of characterization of NI-USRP system and in the end the

    conclusions give in which kind of prototype or simulation that suit the best of NI-USRP system.

  • 27.
    Gaddam, Nagavenkat kumar
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    BLUETOOTH / ZIGBEE NETWORKS AND DEVELOPMENT OF PORTABLE 6LOWPAN STACK2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Wireless sensor networks (WSN’s) are becoming popular in military and civilian applications such as surveillance, monitoring, disaster recovery, home automation and many others. Prolonged network lifetime, scalability, node mobility and load balancing are important requirements for many WSN applications.

    This thesis work presents the investigation of scalability and power consumption in different wireless module such as Bluetooth, Zigbee to deploy in the large scale wireless sensor network application by simulation the network topologies, analysis and comparison of both the wireless module in OPNET and running the WSN application using Zigbee in Real environment.

    In order to increase the scalability and reduce the power consumption we use the Internet protocol version 6 (IPv6) over Low Power Wireless Personal Area Network (6LoWPAN), we worked on the programming of the 6LoWPAN protocol stack and analysis of the results using the perytons network protocol analyzer. 

     

  • 28.
    Gonzales Fuentes, Lee
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    HELPING COGNITIVE RADIO IN THE SEARCH FOR FREE SPACE2012Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Spectrum sensing is an essential pre-processing step of cognitive radio technology for dynamic radio spectrum management. One of the main functions of Cognitive radios is to detect the unused spectrum and share it without harmful interference with other users. The detection of signal components present within a determined frequency band is an important requirement of any sensing technique. Most methods are restricted to the detection of the spectral lines. However, these methods may not comply with the needs imposed by practical applications. 

    This master thesis work presents a novel method to detect significant spectral components in measured non-flat spectra by classifying them in two groups: signal and noise frequency lines. The algorithm based on Fisher’s discriminant analysis, aside from the detection of spectral lines, estimates the magnitude of the spectral lines and provides a measure of the quality of classification to determine if a spectral line was incorrectly classified. Furthermore, the frequency lines with higher probability of misclassification are regrouped and the validation process recomputed, which results in lower probabilities of misclassification.

    The proposed automatic detection algorithm requires no user interaction since any prior knowledge about the measured signal and the noise power is needed. The presence or absence of a signal regardless of the shape of the spectrum can be detected. Hence, this method becomes a strong basis for high-quality operation mode of cognitive radios.

    Simulation and measurement results prove the advantages of the presented technique. The performance of the technique is evaluated for different signal-to-noise ratios (SNR) ranging from 0 to -21dB as required by the IEEE standard for smart radios. The method is compared with previous signal detection methods.

  • 29.
    Gonzales Fuentes, Lee
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. Vrije Universiteit Brussel.
    Barbe, Kurt
    Vrije Universiteit Brussel.
    Van Moer, Wendy
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. Vrije Universiteit Brussel.
    Björsell, Niclas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. University of Gävle, Center for RF Measurement Technologies.
    Cognitive radios: discriminant analysis finds the free space2012In: 2012 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), New York: IEEE conference proceedings, 2012, 2242-2247 p.Conference paper (Refereed)
    Abstract [en]

    Spectrum sensing is an essential pre-processing step for cognitive radio technology. This paper presents a novel method to detect the significant spectral components in measured nonflat spectra, and to estimate the magnitude of the spectral components. Furthermore, the probability that the spectral component was incorrectly classified is available. The algorithm is able to detect the presence or absence of signals in any kind of spectrum since no prior knowledge about the measured signal is needed. Hence, this method becomes a strong basis for a high-quality operation mode of cognitive radios. Simulation results prove the advantages of the presented technique.

  • 30.
    Hailong, Liang
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Evaluation of two Doppler radar systems for proximity sensing2014Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Most of Doppler Radar systems are expensive to build and hard to take out for the testing.Therefore a portable and easy building Doppler Radar system has been implemented in recent years.For this thesis two Doppler radar systems which working in different frequency ranges (24 GHz and 2.4 GHz) shall be implemented with evaluating the possibilities regarding proximity sensing based on radar technology. There are two designs including. One is based on an ‘all-in-one’ chip from RF-beam Microwave and the other is based on components from Mini-Circuits.Those Radar kit were developed by using a frequency modulated continuous wave(FMCW) architecture.

    The radar works in three different modes:Doppler Time Intensity testing,Range Time Intensity and Synthetic Aperture Radar imaging.The whole system work with Matlab by recording the data.Doppler time intensity (DTI) plots with Doppler spectrum of passing vehicles and range-time intensity(RTI) plots with measuring the moving target versus time will be discussed.Synthetic Aperture Radar(SAR) image of urban terrain is acquired. 

  • 31.
    Hamid, Mohamed
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. University of Gävle, Center for RF Measurement Technologies. Communications Systems Lab (CoS), Royal Institute of Technology (KTH), Stockholm, Sweden .
    Barbe, Kurt
    Vrije Universiteit Brussel, ELEC.
    Björsell, Niclas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. University of Gävle, Center for RF Measurement Technologies. Communications Systems Lab (CoS), Royal Institute of Technology (KTH), Stockholm, Sweden .
    Van Moer, Wendy
    Vrije Universiteit Brussel.
    Spectrum sensing through spectrum discriminator and maximum minimum eigenvalue detector: a comparative study2012In: 2012 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), New York: IEEE conference proceedings, 2012, 2252-2256 p.Conference paper (Refereed)
    Abstract [en]

    In this paper we present a new spectrum sensing technique for cognitive radios based on discriminant analysis called spectrum discriminator and compare it with the maximum minimum eigenvalue detector. The common feature between those two techniques is that neither prior knowledge about the system noise level nor the primary user signal, that might occupy the band under sensing, is required. Instead the system noise level will be derived from the received signal. The main difference between both techniques is that the spectrum discriminator is a non-parametric technique while the maximum minimum eigenvalue detector is a parametric technique. The comparative study between both has been done based on two performance metrics: the probability of false alarm and the probability of detection. For the spectrum discriminator an accuracy factor called noise uncertainty is defined as the level over which the noise energy may vary. Simulations are performed for different values of noise uncertainty for the spectrum discriminator and different values for the number of received samples and smoothing factor for the maximum minimum eigenvalue detector.

  • 32.
    Hamid, Mohamed
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Björsell, Niclas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Frequency Hopping for Fair Radio Resources Allocation in TVWS2015In: ICWMC 2015: The Eleventh International Conference onWireless and Mobile Communications / [ed] Carlos Becker Westphall, Iwona Pozniak-Koszalka, Eugen Borcoci & Dragana Krstic, 2015, 71-76 p.Conference paper (Refereed)
    Abstract [en]

    Using frequency hopping for fair resources allocation in TV white spaces is proposed and evaluated in this paper. The degree of fairness is judged by the achieved throughput by different secondary users. The throughput of the secondary users is determined by their permissible transmission power and the interference from the TV and other secondary users. The permissible transmission power for secondary users in TV white spaces in different channels is investigated. The main concern of calculating the permissible secondary user transmission power is protecting the primary TV receivers from harmful interference. With the aid of SPLAT (RF Signal Propagation, Loss, And Terrain analysis tool), the received TV signal power in a study case of the surroundings of the city of Gävle is fetched. The interference from the TV transmission into the free channels is measured in six different locations. The simulated system is a deployed Wi-Fi access points in a building representing an office environment in an urban area. Moreover, the size of the hopping set and the number of APs influences are investigated.

  • 33.
    Hamid, Mohamed
    et al.
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Björsell, Niclas
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Geo-location Spectrum Opportunities Database in Downlink Radar Bands for OFDM Based Cognitive Radios2011Conference paper (Refereed)
    Abstract [en]

    In this paper a model to investigate the spectrum opportunities for cognitive radio networks in three radar frequency bands L, S and C at a specific location is introduced. We consider underlay unaware spectrum sharing model. The Secondary System we assume is an OFDM based system. The followed strategy is built upon defining a specific co or adjacent channel as a spectrum opportunity if -and only if- the interference generated by the secondary system occupying that channel  into the radar system is less than the permissible interference defined by the value of Interference to Noise ratio (INR) and the radar receiver inherited noise level. The simulation results show that for the same transmission parameters C band offer more spectrum opportunities than S band which is itself offers more spectrum opportunities than L band.

  • 34.
    Hamid, Mohamed
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Björsell, Niclas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Maximum Minimum Eigen Values Based Spectrum Scanner in GNU Radio2011In: RFMTC11, Gävle, 2011Conference paper (Other academic)
  • 35.
    Hamid, Mohamed
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. University of Gävle, Center for RF Measurement Technologies.
    Björsell, Niclas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. University of Gävle, Center for RF Measurement Technologies.
    Maximum Minimum Eigenvalues Based Spectrum Scanner for Cognitive Radios2012In: 2012 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), New York: IEEE conference proceedings, 2012, 2248-2251 p.Conference paper (Refereed)
    Abstract [en]

    In this paper we introduce a technique for spectrum scanning with the maximum minimum eigenvalue detection based spectrum sensing. The fundamental problem we address in this paper is the inability of using maximum minimum eigenvalue detection with filtering in time domain where the white noise becomes coloured. The solution we propose here is based on frequency domain rectangular filtering. By frequency domain rectangular filtering we take the spectral lines inside each sub-band and throw out the rest. After doing the frequency domain rectangular filtering, we generate the corresponding time domain signal and inject it to the maximum minimum eigenvalue detector. An experimental verification has been performed and the obtained results show that the technique is implementable with a performance better than the energy detector as a reference technique in terms of the probability of detection when both technique have the same probability of false alarm.

  • 36.
    Hamid, Mohamed
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. KTH.
    Björsell, Niclas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Van Moer, Wendy
    Vrije Universiteit Brussel.
    Barbé, Kurt
    Vrije Universiteit Brussel.
    Slimane, Ben
    KTH.
    Blind Spectrum Sensing for Cognitive Radios Using Discriminant Analysis: A Novel Approach2013In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, Vol. 62, no 11, 2912-2921 p.Article in journal (Refereed)
    Abstract [en]

    In this paper, we present a new spectrum sensing technique for cognitive radios based on discriminant analysis called spectrum discriminator. The presented technique uses the knowledge of the noise uncertainty and a probabilistic validation to overcome the limitations of the discriminant analysis. A comparative study between the proposed technique and the maximum-minimum eigenvalue detection has been performed based on two performance metrics: the probability of false alarm and the probability of detection. The spectrum discriminator has been further developed to a peel-off technique where all primary users can be detected. The performance of the spectrum discriminator and the peel-off technique has been tested on simulations and experimentally verified. The comparative study is based on simulations as well as measurements.

  • 37.
    He, Shabai
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Simulation of wireless communications in underground tunnels2012Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    The new released 4G standard wireless communication reminds us that higher transmission data rate and more reliable service are required urgently. However, to fulfill the demand can face problems in a complex environment like mines. In this thesis, characterization of underground tunnel mines with the idea of combating intersymbol interference effect is presented.

               Ray tracing simulation method is applied to characterize channel impulse response in different positions of an underground tunnel. From this channel impulse response, we can obtain how intersymbol interference affects different wireless systems. Intersymbol interference occurs due to multipath propagation of time dispersion channel.

              Adaptive Equalization is the most effective way to compensate intersymbol interference. Adaptive filter adapts filter coefficients to compensate the channel so that the combination of the filter and channel offers a flat frequency response and linear phase. The bit error rate performance without using adaptive equalization is compared with using equalizer. Moreover, adaptive equalization approaches using RLS and LMS algorithms are compared with each other. The tradeoff between convergence rate, computation cost instability and ensemble averaged minimum squared errors are analyzed to determine how to select the optimum adaptive equalizer.

  • 38.
    Hossain, Md.Maruf
    University of Gävle, Department of Technology and Built Environment.
    ''Design of RF Front End for Multi-Band Multi-System GNSS Receiver''2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    The up growing wireless communication field always need such a system which is simple but more reliable for multiple applications. To fulfill these demands the modern receiver RF frontend can play an important role. A successful design could be a better solution, not only simple but also modern receiver architecture topology is necessary.The main objective of this dissertation is to design a simple RF-Front end for both multi-band multi-systems Global Navigation Satellite System (GNSS i.e. GPS and Galileo) receiver which

    will provide civil signals on multiple frequencies, similar to those currently available for only military purpose and finally implement and test the receiver front end. Different topologies have been investigated and finally the direct digitization RF front end receiver topology is chosen for simplicity, cost and performance. The entire RF front receiver consists of a broad band LNA, a broad band pass filter and a band stop filter. This kind of receiver needs a minimum feasible sampling frequency which is 434 MHz for designed methodology.A simple receiver RF front end for GNSS application is designed to demonstrate and it has been implemented and tested. The receiver is yield the minimum power consumption which is 26mA

    current from 3V power supply.Although, there are no such a specifications for combined future GPS/Galileo receiver, the

    simple design performance is satisfactory and it will be an interesting future work from commercial point of view.

  • 39.
    Hossain, Zakir
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Planar Antennas for Terahertz Detectors2012Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    The use of the millimeter-wave and terahertz (THz) systems are becoming very important in various scientific and military applications. In many applications i.e. radio-astronomy, THz imaging, remote sensing, secure communication links, THz radars, plasma diagnostics etc. the use millimeter-wave and THz technologies are increasing rapidly and in these applications, integreted lens antennas are porividing attractive solutions. But perfect modeling  and simulation of the lens antenna and beam pattern calculation is still a challenge for the antenna engineers.

     

                In this thesis project thorough investigation has been done to optimize the simulation technique in the EM simulator CST MWS to get reliable and accurate simulation results which may replace the time consuming, complex and expensive measurements in sub-millimeter/THz frequency range. Different experiments are done by retriving from the publications related to this project for the result comparison.

     

                Later on with this optimized simulation process an extended hemispherical lens antenna integrated with log-spiral feed is designed for THz frequency range. Most of the desired goals are achieved during the design process as the design goal is to produce a constant radiation beam and polarization over the a broad bandwidth (500GHz-750GHz)

  • 40.
    Ikram, Amna
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Design and development of a multiband loop antenna for cellular mobile handsets2010Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
  • 41.
    Ikram, Amna
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. University of Gävle, Center for RF Measurement Technologies.
    Beckman, Claes
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. University of Gävle, Center for RF Measurement Technologies.
    Irmscher, Stefan
    Laird Technologies.
    Design and Development of a Multiband Loop Antenna for Cellular Mobile Handsets2011In: IEEE International Workshop on Antenna Technology, 2011, 251-254 p.Conference paper (Refereed)
    Abstract [en]

    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.

  • 42.
    Jabita, Abdul-Nafiu Abiodun
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Design of Singly Split Single Ring Resonator for Measurement of Dielectric Constant of Materials using Resonant Method2013Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Scientists and engineers measure dielectric constant because it gives them better understanding of materials and helps them to know how to integrate these materials into their design processes;it also helps them to shorten design life cycle,and aside these two functions,it has numerous uses all of which cannot be enumerated in this section.Owing to its usefulness,various measurement methods of dielectric constant of materials have been developed over the years.Each method has its limitations which affect the accuracy of the measurement;these limitations range from frequency,temperature,and  mearsurement environment to material under test.

     

    In this thesis,four most common methods of measuring dielectric constant were discussed and the most accurate one,the resonant method,was chosen and worked on .The project was executed by making a mathematical analysis of the ring resonator which was later simulated in HFSS to get results which would be comparable to ones obtained in  laboratory measurements.

     

    The ring was fabricated and taken to the laboratory for measurement.Two monopole antennas were connected to the two ports of a VNA with one antenna serving as the transmitter and the other serving as the receiver.

     

    The resonant frequencies obtained were combined with the geometric parameters of the ring resonator and that of the MUT in equations written into MATLAB scripts;this equations were used to extract the dielectric constant of the MUT.

  • 43.
    Jawdat, Suzan
    University of Gävle, Department of Technology and Built Environment.
    Dynamic nonlinear pre-distortion of signal generators for improved dynamic range2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis, a parsimoniously parameterized digital predistorter is derived for linearization of the IQ modulation mismatch and the amplifier imperfection in the signal generator [1]. It is shown that the resulting predistorter is linear in its parameters, and thus they may be estimated by the method of least-squares. Spectrally pure signals are an indispensable requirement when the signal generator is to be used as part of a test bed. Due to the non-linear characteristic of the IQ modulator and power amplifier, distortion will be present at the output of the signal generator. The device under test was the IQ modulation mismatch and power amplifier deficiencies in the signal generator.

    In [2], the dynamic range of low-cost signal generators are improved by employing model based digital pre-distortion and the designed predistorter seems to give some improvement of the dynamic range of the signal generator.

    The goal of this project is to implement and verify the theory parts [1] using data program (Matlab) to improve the dynamic range of the signal generator. The design digital pre-distortion that is implemented in software so that the dynamic range of the signal generator output after predistortion is superior to that of the output prior to it. In this project, we have observed numerical problems in the proposed theory and we have found other methods to solve the problem.

    The polynomial model is commonly used in power amplifier modeling and predistorter design. However, the conventional polynomial model exhibits numerical instabilities when higher order terms are included, we have used the conventional and orthogonal polynomial models. The result shows that the orthogonal polynomial model generally yield better power amplifier modeling accuracy as well as predistortion linearization performance then the conventional polynomial model.

  • 44.
    Khan, Jahanzeb
    University of Gävle, Department of Technology and Built Environment.
    Design of Microstrip Patch Antenna on Liquid Crystal Polymer (LCP) for Applications at 70GHz2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    The demand of small size electronic systems has been increasing for several decades. The physical size of systems is reduced due to advancements in integrated circuits. With reduction in size of electronic systems, there is also an increasing demand of small and low cost antennas. Patch antennas are one of the most attractive antennas for integrated RF front end systems due to their compatibility with microwave integrated circuits. To fulfil the demand of integrated RF front end systems, a design of microstrip patch antenna with optimum performance at 70GHz is investigated. The procedure could be extended to design other planar antennas that act in a similar way.

    In this work, three different design methods to design patch antennas for applications at 70GHz are investigated that include use of analytical models, numerical optimization, and numerical variation of dimensions. Analytical models provide a basic understanding of the operation of a patch antenna and they also provide approximate dimensions of a patch antenna for a targeted frequency without using numerical simulations. However, as the operating frequencies of RF systems reach mm-wave frequencies, we expect that the accuracy of analytical models become less accurate. For example, the excitation of substrate modes and effect of ground size are not predicted in simple analytical models.

    Due to these expected limitations of the analytical design methods, the accuracy of these models is investigated by numerical electromagnetic field simulations. In this work, CST Microwave Studio Transient Solver is used for that purpose. In order to make sure that the appropriate settings of the solver are applied, the simulation settings such as mesh density, boundary conditions and the port dimensions are investigated. The simulation settings may affect computation time and convergence of the results. Here, in this work, the accuracy of the simulator for a specific design of inset feed rectangular patch antenna is verified. The patch dimensions obtained from analytical calculations are optimized at 70GHz by using the optimizer of the transient solver. The patch dimensions obtained from optimizer are verified by varying the patch dimensions in equidistant steps around the found result of the optimizer.

    In a rectangular microstrip patch antenna design, the use of a width of 1.5 times the length is an approximate rule of thumb [1] for low dielectric constant substrates. It is also investigated how the performance properties of a microstrip patch antenna are affected by varying the width to length ratio of the patch. There are occasions where a different ratio is required because of space limitations, or to change the input impedance. The patch designs having various width to length ratios were optimized with the feed location.

    The analytically calculated dimensions provided good initial values of the rectangular patch antenna for further optimization using more accurate techniques. The design have been optimized at 70GHz for the investigated mesh density, boundary conditions and the port dimensions. The numerical variation of dimensions is found to be most reliable among the investigated design methods but it is more complicated with many parameters.

  • 45.
    Kota, Madhava Reddy
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development.
    Shrestha, Binod
    University of Gävle, Faculty of Engineering and Sustainable Development.
    Global Backprojection for Imaging of Targets Using M-sequence UWB radar system2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Synthetic Aperture Radar (SAR) is an emerging technique in remote sensing. The technology is capable of producing high-resolution images of the earth surface in all-weather conditions. Thesis work describes the present available methods for positioning and imaging targets using M-sequence UWB (Ultra-Wideband) radar signals with moving antennas and SAR algorithm to retrieve position and image of the target.

    M-sequence UWB radar technology used as signal source for transmission and receiving echoes of target. Pseudo random binary sequence is used as a transmitted signal. These radars have an ability to penetrate signal through natural and unnatural objects. It offers low cost and quality security system. Among a number of techniques of image retrieval in Synthetic Aperture Radar, study of Global back projection (GBP) algorithm is presented. As a time domain algorithm, GBP possesses inherent advantages over frequency domain algorithm like ability to handle long integration angle, wider bandwidth and unlimited aperture size. GBP breaks the full synthesis aperture into numbers of sub-apertures. These sub-apertures are treated pixel by pixel. Each sub-aperture is converted to a Cartesian image grid to form an image.  During this conversion the signal is treated with linear interpolation methods in order to achieve the best quality of the images.

    The objective of this thesis is the imaging of target using M-sequence UWB radar and processing SAR raw data using Global back projection algorithm. 

  • 46.
    Landin, Per
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. KTH, Signalbehandling.
    Digital Baseband Modeling and Correction of Radio Frequency Power Amplifiers2012Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Aspects related to behavioral modeling and correction of distortions for radio frequency (RF) power amplifiers (PAs) are treated in the thesis.   

    When evaluating the performance of a behavioral model it is important to, first of all, use an evaluation criterion, and second, make sure that the criterion actually tells something about the behavior one wishes to describe. This is used in the weighted error spectral power ratio (WESPR) criterion by means of a frequency dependent weighting function. When the parameters of the models are estimated a suitable error criterion should likewise be used. The frequency weighting function in the WESPR is used in the extraction of the parameters. It is shown on two types of PAs that the model performance measured as WESPR can be improved while the model complexity is reduced compared to the standard frequency neutral criterion.   

    When building a model of a system it is advantageous to take account of the physical structure and incorporate this knowledge into the model. It can improve model performance and possibly reduce the number of parameters. By starting from a physically motivated nonlinear model of a RF PA, the commonly used memory polynomial (MP) models are derived. Additionally, three novel MP model structures are derived. Using data measured on a PA it is found that two of these model structures have lower model errors while using fewer parameters than models previously published in the literature.   

    Methods to increase the power efficiency and the linearity of RF PAs have been investigated. One of these methods is digital predistortion (DPD) which improves the linearity, thus facilitating operation at higher power levels which improves power efficiency. The other method is a signal shaping method that makes the signal more favorable to the PA by reducing the highest peaks to lower values. It is experimentally shown that the combination of DPD and signal shaping results in an increase of power efficiency in the order of 2-4 times. An instability in the feedback loop that updates the parameters of the DPD was also identified and two solutions were proposed. One solution changes the parameters of the DPD in such a way that the instability is avoided and the other changes the signal to avoid high amplitudes.   

    The nonlinear effects of class-D outphasing amplifiers are considered. Four model structures are proposed and evaluated on data measured from two amplifiers. In order to reduce the distortions in the output signal from the amplifiers an algorithm using constant envelope amplitude (purely phase-modulated) signals is proposed. The DPD is evaluated and found to reduce the distortions in a state-of-the-art 32 dBm class-D outphasing PA to make it fulfill the linearity requirements for downlink signals used in the universal mobile telecommunications system (UMTS).

  • 47.
    Landin, Per
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Barbé, Kurt
    Vrije Universiteit Brussel.
    Van Moer, Wendy
    Vrije Universiteit Brussel.
    Isaksson, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Händel, Peter
    KTH Royal Institute of Technology.
    Proofs of Derivations in Memory Polynomial Baseband Modeling of RF Power Amplifiers2011Report (Other academic)
    Abstract [en]

    This paper contains supporting derivations for the paperMemory Polynomial Baseband Modeling of RF Power Am-plifiers. All references to numbered equations, propositionsand assumptions are to the corresponding number inMemoryPolynomial Baseband Modeling of RF Power Amplifiers.

  • 48.
    Landin, Per
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Keskitalo, Niklas
    University of Gävle, Center for RF Measurement Technologies.
    Tornblad, Olof
    Infineon Technologies.
    Sideband asymmetries in RF Power LDMOS Before and After Digital Predistortion2009Conference paper (Other academic)
    Abstract [en]

     The merging of the fields of RF engineering and signal processing has introduced concepts such as behavioral modeling and enabled digital linearization schemes for wireless devices, such as power amplifiers (PAs). Despite that this process has been going on for a number of years much work remains to be done. The links between physical behavior and mathematical models are far from well-understood as are the optimum strategies for device design. This study focus on digital predistortion properties of a one-stage PA consisting of a power transistor mounted in a test fixture. The device under test (DUT) is an Infineon PTF210451E, a 45W transistor intended for usage in the frequency bands 2010-2025 MHz and 2110-2170 MHz. The test fixture is also designed by Infineon Technologies.  The signal types used in the measurements are single and double carrier wideband code division multiple access (WCDMA) signals. The double carrier WCDMA signals have tone-spacings of 5, 10 and 15 MHz. Normal two-tone measurements are also presented. 

  • 49.
    Landin, Per
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Nader, Charles
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Van Moer, Wendy
    Vrije Universiteit Brussel.
    Björsell, Niklas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Isaksson, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Händel, Peter
    KTH Royal Institute of Technology.
    Overview of Synergetic OFDM Crest Factor Reduction and DigitalPre-Distortion for RF PAs2011In: RFMTC11, 2011Conference paper (Other academic)
    Abstract [en]

    Digital baseband pre-distortion (DPD) is used tolinearize nonlinear RF PAs, crest factor reduction (CFR) toincrease the maximum output power level of RF PAs. Togetherthey result in increased output power with maintained, or even,better linearity. This paper discuss some of the techniquesfor DPD and CFR methods currently under investigation.Measured results for a class-AB PA using OFDM signalsindicate a possibility to increase the power added efficiency(PAE) by at least 15%-points, from 30%to 45%, and a poweroutput increase of 6 dB while maintaining specified ACLRrequirements.

  • 50.
    Landin, Per Niklas
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Barbé, Kurt
    Vrije Universiteit Brussel.
    Van Moer, Wendy
    Vrije Universiteit Brussel.
    Isaksson, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Händel, Peter
    KTH Royal Institute of Technology.
    Memory Polynomial Baseband Modeling of RF Power AmplifiersIn: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456Article in journal (Refereed)
123 1 - 50 of 103
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