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Radioelektronika, 2008 18th International Conference

Date 24-25 April 2008

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  • Proceedings of the 18th international conference radioelektronika 2008

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    The following topics are dealt with: signal processing; audio-video technologies; image processing; radio communication and navigation system; RF circuit and measurement. View full abstract»

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  • Session index

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    Freely Available from IEEE
  • An adaptive filter based on multigrid linear equation solvers

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (358 KB) |  | HTML iconHTML  

    A recent and novel approach to the development of adaptive filtering algorithms is based on the theory of stationary iterative linear equation solvers: A classical Richardson iteration, possibly preconditioned, is applied to the Wiener-Hopf equation. Substituting estimates for various statistical quantities in the resulting recursion, a large number of classical and modern adaptive filters are developed with ease within a unified framework. Taking further inspiration from the field of numerical linear algebra, in this paper we make use of the multigrid paradigm, mostly used in the numerical solution of partial differential equations and their corresponding discretized linear equation sets, to devise a simple, yet robust adaptive filter with better performance than the NLMS algorithm. View full abstract»

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  • Data transmission over voice dedicated channels using digital modulations

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    With the actual expansion in communication systems, data channels are taking more importance, especially in mobile data networks. But in some cases the transmission over data channels is not possible or not convenient, which makes the data transmission over voice channel an interesting alternative. Firstly, the operators of mobile phone networks (GSM, GPRS) tend to limit the access to the Internet in order to prevent Voice over IP (VoIP) for economical reasons. Secondly, the cross- networks bridges used in VoIP (VoIP-ISDN, VoIP-GSM, VoIP-PSTN) give an opportunity to transmit data over this voice channel without any additional data bridges. Thirdly, for security matters, transiting data dissimulated in a voice-like signal is more discrete. Lastly, some communication networks such as THURAYA are dedicated to voice communications. View full abstract»

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  • Blind receiver based on the LCCMA algorithm for MC-CDMA signals detection over the 3-states channel model

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (785 KB) |  | HTML iconHTML  

    Blind detection is one of the most perspective techniques in signal processing theory. In this paper we describe blind detector based on the linearly constrained constant modulus algorithm (LCCMA). Simulations are oriented on multi-carrier code division multiple access (MC-CDMA) signals when turbo codes are used for error correction of transmitted images. We had investigated the system bit error rate (BER) performance in 3-states channel enlarged with a complex AWGN (additive white Gauss noise) noise. The channel model is assigned for land mobile satellite (LMS) communications. The application of turbo coding strengthens the system ability to cope with multi-path fading and multi-access interference (MAI) significantly. View full abstract»

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  • Architecture of invariant transform based traffic sign recognition system

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (509 KB) |  | HTML iconHTML  

    Driver assistance system try to help driver in driving process, support him with all possible information, that can be obtained from different sensors installed in the car, or take control over the car if it is necessary. Many of these systems are in develop, and many groups of scientist (engineers) are searching for new methods to solve different problems in this field (vehicle detection, traffic sign detection, license plate recognition, pedestrian's detection, etc.). In this paper we focus on traffic sign recognition. New developed invariant transform based traffic sign recognition system is here described. The architecture of proposed system involves fast processing method and method based on invariant transform. Experiments are shown and potential application of this system is discussed. View full abstract»

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  • Realization of arbitrary transfer current characteristic using transconductors CDTA

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (460 KB) |  | HTML iconHTML  

    Active RC circuits with arbitrary transfer characteristics in current mode are presented in this paper. The given circuits are based on the multiple-loop feedback structure, namely on the follow-the-leader feedback structure with output summation. Modeling by signal flow graph technique is used to modify and transform the structure in current mode. Implementations by multi-output current-differencing-input transconductors (CDTA) are given. Verification and illustration are shown. The designed circuits have been simulated in PSpice and SNAP, resulting responses are confirming the theoretical assumptions. View full abstract»

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  • OFDM PAPR reduction by Partial Transmit Sequences and Simplified Clipping with Bounded Distortion

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (452 KB) |  | HTML iconHTML  

    This paper is focused in the domain of peak to average power ratio (PAPR) reduction of orthogonal frequency division multiplex (OFDM) signals. Combination of partial transmit sequences (PTS) and simplified clipping and filtering with bounded distortion (SCAFBD) is proposed. The first mentioned method is distortionless, but needs to transmit a side information in every OFDM symbol. The second method introduces signal distortion. The combination of methods results in better PAPR reduction and lower bit error rate (BER). The performance is evaluated in AWGN channel. View full abstract»

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  • Throughwall imaging of the objects scanned by M-sequence UWB radar system

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1087 KB) |  | HTML iconHTML  

    UWB radar system facilitates us to estimate positions and shapes of objects behind the wall. We have made real through the wall SAR measurements with bistatic M-sequence UWB radar system. A metal plate, an aquarium filled with water and a wooden cupboard inside the room with concrete wall have been scanned. The simple and fast algorithm for compensation of different wave velocity inside the wall is described. Measured data are processed with 2-dimensional geometrical based SAR migration in time domain. Conductive materials behind the wall scanned with M-sequence UWB radar system are clearly visible. View full abstract»

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  • FM demodulation of IQ baseband signals using Kalman filters

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (599 KB) |  | HTML iconHTML  

    Frequency or phase modulated electrical signals arise in multiple applications in communication systems as well as in measurement setups such as interferometry / vibrometry, velocimetry etc. Common demodulation techniques are often based on analog techniques (e.g. a PLL in the RF band) or - after mixing into the base band and generating IQ signals - on digital signal processing algorithms. Two DSP based algorithms for the frequency demodulation of lQ baseband signals will be presented and compared in this paper. One of them is the synthetic heterodyne approach, based on the digital derivation of the arctan of the angle described by the I and Q component. It will be shown, that this algorithm is very sensitive to noise in the baseband signals. The other, more modern algorithm uses a Kalman filter as an "optimal" estimator of the instantaneous phase and frequency of the two signals. It will be shown that the Kalman filter shows a drastically improved noise performance. View full abstract»

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  • Object localization using round trip propagation time measurements

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (549 KB) |  | HTML iconHTML  

    The object localization belongs to the basic tasks solved within wireless sensor networks (WSN). It can be shown, that for WSN based on UWB radar systems, localization methods using round trip propagation times can be used with advantages [1]. In this paper we introduce three localization methods of that kind, i.e., a direct calculation, a conventional and weighted least-squares methods and a Taylor series method. It is expected, that these methods can be applied especially for UWB WSN. The properties of the proposed methods will be illustrated by using computer simulations. It will be shown, that Taylor series method can provide the best estimate of object location. View full abstract»

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  • Optimalization of GMM for text independent speaker verification system

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (482 KB) |  | HTML iconHTML  

    This paper presents automatic verification system based on the voice recognition technology. System works as text independent and is designed to verify a person using a short utterance. GMM method is used for speaker modeling and GMM-UBM classifier is used for process of decision. The main goal of experiments in this paper is to finding the optimum size of the GMM and UBM models (optimum numbers of components). Experimental evaluation of the system is conducted on the database of 24 people, where around 6 minutes of speech data from one person is available for training and 3 types of utterances with different lengths from 1 to 9 seconds are available for testing. View full abstract»

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  • Simulation and experimental testing of the DVB-T broadcasting in the SFN networks

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    This paper deals with the transmission of the digital television signal according to the DVB-T standard in SFN network and fixed reception. The laboratory transmission system for simulated broadcasting based on R&S RF test and measurement equipments is presented. The results of bit-error rates and S/N ration in the channel of simulated DVB-T broadcasting in SFN using two transmitters and SFN echo interference are presented and discussed with the theory. View full abstract»

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  • Estimating PSNR without reference for real H.264/AVC sequence intra frames

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2367 KB) |  | HTML iconHTML  

    The paper describes a novel metric for video quality measurement. The metric is capable of estimating peak signal-to-noise ratio (PSNR) values of pictures in compressed bit streams conforming to the H.264/AVC standard. It is designed and has been tested for intra predicted pictures with varying encoder settings. The metric uses an artificial neural network to estimate PSNR examining the compressed bit stream only. In other words, we do not need to decode the actual pixels within the pictures being evaluated. View full abstract»

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  • Robust image watermarking based on the synchronization template

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1520 KB) |  | HTML iconHTML  

    Digital watermarking is a potential effective method for authentication and ownership rights protection. The digital watermark is hidden information added into the multimedia. This paper presents robust digital watermarking in images. One robust digital watermarking based on the synchronization template is presented and some experimental results are presented too. View full abstract»

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  • Signal processing for through wall moving target tracking by M-sequence UWB radar

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (716 KB) |  | HTML iconHTML  

    In this paper, through wall moving target tracking by UWB radar is described as a complex process with all required phases of radar signal processing. For particular phases of that process, i.e. for raw radar data preprocessing, background subtraction, detection, trace estimation, localization and tracking itself, the phase significance and its corresponding representative methods are outlined. The complete process is illustrated by the results of processing of real data acquired by M-sequence UWB radar. View full abstract»

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  • MEMS technology in head tilt monitoring after vitreoretinal surgery

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (838 KB) |  | HTML iconHTML  

    Presented paper is focused on a new developing device intended for monitoring of patient's head position during the post-operative period after vitreoretinal surgery. Keeping the head in an optimal position after this operation is crucial for optimal results of the recovery process. Head tilt monitoring is a complicated task during the normal life. Described device is based on a modern micro-electro-mechanical systems (MEMS) acceleration sensor. MEMS sensors are used for sensing gravitational acceleration. A microcontroller is used for data processing, logging and controlling user interface. View full abstract»

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  • Non-line-of-sight mitigation technique in wireless location system

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (450 KB) |  | HTML iconHTML  

    Non-line-of-sight (NLOS) error is the most common and also a major source of errors in wireless location system. This paper presents an approach to ameliorate the effect of the NLOS using Time Difference Of Arrival (TDOA) with more than minimum number of base stations (BSs). This algorithm makes use of the redundant TDOA measurements to formulate a problem as a test of hypothesis in order to get a hard decision to discard the NLOS-BSs, comparing with one certain ratio proposed in this paper, and it has no use for the distributing probability of the NLOS noise. Numerical simulations show that the proposed algorithm can completely discard the NLOS-BSs when NLOS error is higher than the measurement noise. View full abstract»

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  • MC-CDMA performance analysis for different spreading codes at HPA Saleh model

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (567 KB) |  | HTML iconHTML  

    Multi-carrier code division multiple access (MC- CDMA) is a powerfull modulation technique that is being considered in many emerging broadband communication systems. However the high peak to average power ratio (PAPR) of the MC-CDMA signal, a special drawback of multicarrier transmission, has limited its wider aplication due to inefficient use of power amplifiers. PAPR strongly depends on particular spreading sequences considered for transmission. Therefore, the performance analysis of uplink MC-CDMA for different spreading sequences and for different receivers in the presence of Saleh model of high power amplifier (HPA) is presented. The results of our analysies show that the aplication of Golay codes in conduction with micro statistic multi-user receiver (MSF-MUD) provide significant better result as the other investigated spreading sequences and receivers. View full abstract»

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  • Air traffic control radar tester

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (696 KB) |  | HTML iconHTML  

    Our aim is to develop a radar tester equipment for commercial and military services. The task is to create one (or more) target or clutter on the radar screen with given distance, velocity and fluctuation. This equipment is placed within few hundred meters from the radar, so it is able to analyze the whole radar system from the antenna, via microwave hardware elements, to the DSP unit. We have some experience in this field, included in the references but also briefly introduced in this paper. View full abstract»

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  • DS-CDMA signal blind MMSE detector adaptation

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (485 KB) |  | HTML iconHTML  

    The contribution is focused on multiuser detection of code-division multiplexed signals - direct- sequence CDMA. A very efficient detection of an individual signal within synchronous CDMA mitigating multiuser interference as well as additive noise is MMSE multiuser detection. Its adaptive version minimizes the prior information necessary for an optimized detector design. In the contribution the optimization of parameters of detectors based on steepest descent of target MMSE penalty function is summarized. View full abstract»

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  • Packet scheduling in UMTS

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    This paper deals with the bit rate allocation methods, which are parts of the packet scheduling process. This process, together with access control, congestion control and others, ensures QoS in UMTS. In this paper, a fair throughput packet scheduling algorithm and two versions of fair resources packet scheduling algorithm are described. Simple simulations show a comparison of these three algorithms. View full abstract»

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  • Bluetooth EDR Physical Layer modeling

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (525 KB) |  | HTML iconHTML  

    This paper deals with the Bluetooth Physical Layer simulation in Mathworks Matlab. Models for basic rate and enhanced data rate mode were made. Simulations for 1, 2 and 3 Mbit/s data rates are presented. All of the Physical Layer processing including scrambling, forward error correction and packetization is simulated. Baseband simulations of transmission over AWGN channel are introduced and graphical results are compared with the theory. All Bluetooth simulations are part of the Bluetooth and Wi-Fi coexistence research. View full abstract»

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  • The optimized concentrator placement problem solution using GIS

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (427 KB) |  | HTML iconHTML  

    The goal of this paper is to introduce an algorithm for optimized repeater station placement using a digital terrain profile taken from the GIS (Geographic information system) database of Slovak Republic. Not only are the terrain profile and the radio link range included into consideration, but also the power source availability. The algorithm can be used to design a radio-communication access network of a UMTS/GSM mobile provider or any network using radio links. The basic optimization criterion is the network cost. Secondary also network reliability is taken into account. So a cost effective and computer supported optimized design of radio network topology became possible. View full abstract»

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  • Noncoherent recognition of OFDM modulation

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (444 KB) |  | HTML iconHTML  

    This paper deals with noncoherent recognition of modulation types. The main goal is to discriminate a multi-carrier OFDM modulation type from some single-carrier analog and digital modulation types. The proposed solution uses statistics of the received signal, which is observed on the signal amplitude at the output of the intermediate-frequency stage. Not only AWGN noise is used to verify the properties of the recognizer, but also presence of the multi-path propagation. View full abstract»

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