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Please follow the links to view the publication.Theory and practice for modelling the broadband acquisition in HF transmissions
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0401
Traditional use of the HF band is limited mostly to 3 KHz for both voice and data transmission, and therefore, most of the transceivers bandwidths are also adapted to this profile. However, there are some initiatives that clearly state that much broader bandwidths may be use with the corresponding data rate increase and performance improvement in the HF band [1,5]. Due to the increased bandwidth, a broadband transceiver receiver has to cope with a broader acquisition bandwidth with strong signals that degrade the Analog to Digital Converter (ADC) performance while receiving our (often) much weaker desired signals. This current paper has three main steps in order to evaluate under which circumstances the degradation is noticeable regarding the interchannel separation and the powers ratio. Indeed, our objective is to determine how much the interference has to be mitigated in the analog domain in order to split its cancellation partly before the ADC, and partly after it in the digital domain where much powerful techniques are available. (5 pages)A practical method of calculating delay spread from VOACAP predictions
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0375
In this paper, a Monte Carlo method has been applied to calculating the multipath spread of HF signals from VOACAP predictions. This method uses the predicted SNR probability distribution functions rather than just taking the median SNR to provide a probability distribution of multipath spread values. Predictions are compared with measurements over two paths, one at mid-latitudes and the second at sub- auroral latitudes. At mid-latitudes, the predictions are generally consistent with observation at higher frequencies, but underestimate the spread at lower frequencies during the day. For the sub-auroral path, the predicted spreads are higher than those observed at all times of day. The new method will be useful to those planning or operating digitally modulated radio systems in the HF band since these can be adversely affected by multipath spread. (5 pages)Gaussian mixture PHD filter for multi-target tracking using passive Doppler-only measurements
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0417
In this paper, we analyze the performance of the Gaussian mixture probability hypothesis density (GM-PHD) filter in tracking multiple non-cooperative targets using a passive sensor network. Non-cooperative transmissions from illuminators of opportunity like GSM base stations, FM radio transmitters or digital broadcasters are exploited by non-directional separately located Doppler measuring sensors. Clutter, missed detections and multi-static Doppler variances are incorporated into a realistic multi-target scenario. Simulation results show that the GM-PHD filter success fully tracks multiple targets using only Doppler shift measurements in a passive multi-static scenario. (6 pages)Track degradation as a consequence of distributed sensor fusion
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0408
It is often taken for granted that measurement-level data fusion must necessarily give rise to an improvement in the track picture, particularly in situations where the sensors are spatially distributed. In many cases, this assumption is justified - an obvious example is where each sensor individually produces too sparse a set of plots to support a track, whereas multiple sensors can provide a sufficient density of measurements. Another example is where complementary viewing angles can permit more precise target localisation. There are, however, situations in which the provision of information from multiple sensors can actually be detrimental to the tracking of closely-spaced objects. This behaviour has been observed using very high-fidelity simulations of a set of high-range-resolution radars observing closely-spaced ballistic targets. It is shown that the complementary viewing angles provided by distributed sensors can actually increase the likelihood of miscorrelation, in situations in which the closely-spaced objects (CSOs) are resolvable in range but not in angle. An attempt to exploit the individual sensor resolution capabilities by using track-associated plot processing was found to be fragile. An MHT (Multi-Hypothesis Tracking) approach, however, is shown to be a robust solution. (6 pages)Time-varying waveform analysis for power transformer protection using frequency shift empirical mode decomposition
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0053
Empirical mode decomposition (EMD) method is a novel time-frequency analysis tool to analyse non-stationary signals, which decomposes the signal concerned into intrinsic mode functions (IMFs) modulated in terms of both amplitude and frequency. The original version of EMD, however, suffers from an algorithm difficulty to separate two individual components, frequencies of which are within an octave. To improve the frequency resolution, a signal pre-processing method is used to shift the frequencies apart based on signal communication theory. This proposed frequency shift EMD has been successfully applied to extract modal parameters of low frequency oscillations for power systems. In this paper, this method is used to analyse the transient signals (inrush current) in the field of power transformer protection. Comparing with low frequency oscillation signals, these signals include more frequency components with faster dynamics. Numerical simulations are conducted to verify the frequency shift EMD. The results show that this method is adequate for time-varying waveform analysis for power transformer protection, and with the information provided by this frequency shift EMD, more robust protection schemes for power transformer could be proposed. (6 pages)Arc suppression coil preset compensation method by using injection signal
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0127
Most of current arc suppression coil compensation system works based on the magnitude of post-fault distributed capacitance. This system can not offer compensation before fault, so in power system with large distributed capacitance current, short circuit shock is inevitable. This paper proposes an automatic arc suppression coil compensation technology based on fixed-frequency signal injection, it can calculate system equivalent distributed capacitance accurately in normal operation status and then adjust arc suppression coil according to pre-determined compensation degree. This system can offer compensation before the occurrence of single-phase ground fault, and possesses preferable compensation effect for distribution system with flexible operation manner and variable distributed capacitance. This method can also calculate insulation resistor to monitor the insulation status of power system. Laboratory simulation test and field test results indicate that arc suppression coil compensation system based on fixed-frequency signal injection method can offer ideal compensation effect for distribution system. (6 pages)Superiority of decision tree classifier on complicated cases for power system protection
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0054
Diagnosis of power system faults requires identification and classification of voltage disturbances in power systems and smart grids. The objective of this approach is to develop state of art signal classification algorithms for classifying different types of power quality disturbances (faults) based on latest improvements in signal processing and pattern recognition techniques. This paper proposes a new solution for power system monitoring against all possible power quality issues. S-transform is used for analyzing distorted power signal. As a classifier, decision tree algorithm is used and its performance is compared to other classifiers. The proposed hybrid power system monitoring system is able to detect common power system disturbances such as voltage sag/swell/, flicker, DC component, electro-magnetic interference, harmonics, transients and blackouts. (6 pages)Zero location study of the beam response of the maximum output SINR beamformer
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0157
Based on the uniform linear array (ULA) structure, zero locations of the beam pattern of the maximum output SINR (signal-to-interference-plus-noise ratio) beamformer are investigated. It is shown that for an M-sensor array, M - 1 nulls have to be formed in the optimum beam response and all of them are located on the unit circle. Furthermore, the nulls of the beamformer may shift from the real interference DOA angles to achieve the optimum output SINR. Analysis based on a 3-element ULA is provided, supported by simulations. (5 pages)Array shape calibration using a single multi-carrier pilot
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0173
In this paper, a novel single pilot array shape calibration algorithm is proposed for an arbitrary planar array. The method requires a single multi-carrier pilot operating at a known location with respect to the arbitrary array reference point. Typically two or more sources are required to calibrate the shape of a planar array. However, by exploiting the difference in the array response model when the source operates in the "near-far" and "far" field of the array, it is shown how this can be reduced to just one. Simulation results exhibiting the performance of the proposed method are also presented. (6 pages)Characterization of vibrating targets in bistatic SAR
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0146
Motions and micro-motions of objects in an illuminated scene introduces Doppler and micro-Doppler effects in the received echoes. Combining the advantages introduced by the bistatic SAR (BSAR) configuration and the usefulness of the micro-Doppler signature characterization will provide a powerful tool for military and civil applications such as target recognition and classification. In this paper a vibrating micro-Doppler signature for a BSAR system with fixed receiver is analyzed and compared to the signature obtained in a monostatic SAR system. The micro-Doppler effect in a Bistatic SAR system for vibrating targets is analyzed and the derived mathematical model is confirmed with simulations. (5 pages)A calibration methodology for an acoustical array
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0163
A simple "ad hoc" method that allows the calibration of both sensor arrays, in transmission and in reception, for narrow-band acoustic radar systems using beamforming techniques is presented in this paper. This system uses low cost sensors and amplifiers, and for them there are not calibration data of phase and gain characteristics. Using a reference sensor system, auto-calibration procedures for a transmission array and for a reception array have been implemented. Finally, the proposed methodology has been tested on a real system, based on a uniform linear array with 15 lambda/2-equispaced sensors. The degradation that is introduced on beampatterns with and without compensation for several steering angles has been analysed. This methodology can be extrapolated to 2D arrays. (5 pages)Data latency compensation for distributed multi-sensor source localization
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0155
In this publication we propose consensus schemes compensating for data latency and apply these methods for localizing noise sources through distributed sensor networks. The solution generalizes past results on multiple aspects, especially by dealing with time-varying non-uniform delays with an unknown upper bound. In particular, this publication presents a relatively simple edge-weight adaptation scheme improving consensus for situations where sensors have either synchronized or unsynchronized clocks. Simulations of a source localization mission are used to demonstrate and quantify benefits. (5 pages)NG-distribution radar sea clutter embedded with thermal noise
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0166
In this paper we investigate and study the performance of a high resolution cell-average constant false alarm rate (CA-CFAR) radar of a Swerling II target embedded in sea clutter plus additive Gaussian thermal noise. The sea clutter is modelled as NG-distribution. Closed form expressions for probabilities of false alarm and detection are derived. Also, Monte Carlo simulations are carried out to assess the system performance both theoretically and by simulations. (4 pages)A switched-order FLOM STAP algorithm in heterogeneous clutter environment
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0160
The normalized fractionally-lower order moment (NFLOM) algorithm exhibits fast convergence but low steady- state signal-to-interference-plus noise ratio (SINR) when the order is less than two. In this paper, we propose a switched-order NFLOM algorithm to adaptively select the best order to achieve both fast convergence and good steady-state performance. The basic idea is to constrain the order within a range of appropriate values, to compute the space-time adaptive processing (STAP) the best order that maximizes the output SINR. The proposed algorithm is assessed with simulated data considering a heterogeneous clutter environment. The simulation results illustrate that our proposed algorithm outperforms the normalized least mean squares (NLMS) algorithm and the NFLOM algorithm, and has an easier parameter setting than the existing variable-order algorithms. (5 pages)Compressive sensing reconstruction techniques with magnitude prior information
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0151
This paper considers compressive sensing (CS) reconstruction with magnitude prior information. The magnitude prior information is described by mean and covariance of the unknown signal. Towards a reconstruction with minimum mean square errors (MMSE), we propose several CS reconstruction algorithms that use the magnitude prior information. Numerical simulations demonstrate that our approach reduces the reconstruction distortion. Potential applications of the proposed techniques include radio spectrum surveillance, sensor networks, etc. (5 pages)Sparsity-aware STAP algorithms for airborne radar based on conjugate gradient techniques
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0142
In this paper, new sparsity-aware space-time adaptive processing (STAP) algorithms based on conjugate gradient (CG) techniques are proposed. The idea of sparsity-aware STAP algorithms is based on the incorporation of a sparse regularization (l<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">1</sub>-norm) constraint to the minimum variance (MV) design criterion. To solve this optimization problem, two different l<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">1</sub>-based algorithms based on the conventional CG and the modified CG are derived. An analysis of the computational complexity shows that the proposed algorithms have nearly the same cost as the conventional algorithms. It is also demonstrated that the proposed STAP algorithms outperform the conventional algorithms using the simulated airborne radar data. (5 pages)Performance analysis of the data subtraction based robust beamfromer
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0158
Performance of the sample matrix inversion (SMI) beamformer degrades severely due to the finite sample size effect and the arrival angle mismatch problem. A simple technique to provide robustness to the conventional SMI beamformer is to block the desired signal from the received data before calculating the beamformer's weight vector, which leads to the data subtraction based SMI (S-SMI) beamformer. In this paper,d we analyse the performance of the S-SMI beamformer in term of its output signal-to-interference-plus-noise ratio (SINR) in the presence of both finite sample size effect and arrival angle mismatch problem. (5 pages)Low complexity robust beamformer for general-rank signal model based on uniform linear array
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0165
Based on the uniform linear array (ULA) structure and the resultant persymmetric structure of its covariance matrices, a low complexity robust beamformer for an incoherently general-rank signal model is proposed by introducing a preprocessing transformation matrix. The computational complexity is reduced significantly due to a real-valued close-form solution for the optimum weight vector. Moreover, the proposed algorithm can achieve a higher output signal-to-interference-plus-noise ratio (SINR). (4 pages)Remote sensing of a geographical environment with portable radars and satellite link
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0064
The environments such as inaccessible places in forests and deserts obstruct free access to human beings and call for remote access by electronic means to get the geographical nature. This research project deals with the establishment of a system for remotely sensing and gathering the information. Three locations, which reveal the geography in a better manner is decided first and three portable radars are launched into the spots from air As soon as the radars stabilize their positions they start functioning to scan electronically the environment. Beam sweeping is performed for complete coverage of 360 degrees and the action is repeated continuously to get the PPI information of the surroundings. The target information collected at these radar receivers are transferred to satellite link through distributed wireless sensor network. In the remote ground station the information from three radars are processed to extract information about the static and moving objects in the spotted area.Towards assisted living via probabilistic vital-sign monitoring in the home
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0022
This paper describes the development of a reliable multi-sensor data fusion system for monitoring patient vital-signs in the home. Initial investigatory work has taken place using ambulatory hospital patients, in the Oxford Cancer Hospital. Our monitoring approach is based on a probabilistic model of normality learned from a data-set of vital signs acquired from a representative group of high-risk patients. Alerts are provided to carers whenever patient vital signs are deemed "abnormal" with respect to the model of normality. We show examples of how this approach correctly detects physiological deterioration in the target patient group, and describe future work in further validation of the technology in home monitoring applications. (6 pages)DE-noising of EEG signals using Bayes shrink based on Coiflet transform
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0048
The Electroencephalogram (EEG) is a biological signal that represents the electrical activity of the brain. However, the presence of artifacts like Electro-oculogram (EOG), Electrocardiogram (ECG), Electromyogram (EMG) and power-line noise in the EEG signal is a major problem in the study of brain potentials. Hence, these superfluous signals are needed to be removed. There are various methods for removal of artifacts. This paper discusses a wavelet-based approach for correcting the artifacts generated by eye blinks, eyeball movements and facial muscle movements in EEG using threshold called Bayes Shrink based on Coiflet Transform.A wireless approach to device-free localisation (DFL) for indoor environments
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0024
Determining the location of individuals within indoor locations can be useful in various scenarios including security, gaming and ambient assisted living for the elderly. Healthcare services globally are seeking to allow people to stay in their familiar home environments longer due to the multitude of benefits associated with living in non-clinical environments. Technology to determine an individual's movements or lack of movement is key to ensuring that home emergencies are detected and responded to promptly. This paper proposes a device-free wireless-based localisation (DFL) system which would enable the individual to proceed with normal daily activities without the constraint of having to wear a traceable device. The principal behind this is that the human body absorbs/reflects the radio signal being transmitted from a transmitter to one or more receiving stations. The system design procedure facilitates the use of a minimum number of wireless nodes with the aid of a principle component analysis (PCA) based intelligent signal processing technique. Results demonstrate that human detection and tracking are possible to within 1m resolutions with a minimal wireless hardware infrastructure. (6 pages)Brain Music System: standardized brain music therapy
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0029
The paper discusses a standardized therapeutic treatment using the Brain Music System, a system that uses Sonified Neurofeedback accurately and cost effectively to convert brainwaves into musical sound using Digital Signal Processing algorithms. A standard course of sonified neurofeedback therapy (for example 15 sessions), tailored specifically to individual patients, is a realistic possibility due to the inexpensive and portable nature of the system, and could be used both inside or even outside of a traditional clinical setting for subjects suffering from a wide array of mental and neurological conditions. In a pilot study to test the algorithms and output of the Brain Music System, the distribution of the Alpha, Beta and Theta waves in normal subjects corresponds closely to that in published studies using standard high-end equipment (confined to expensive clinical setups). These results allows the Brain Music System to align its protocol to practice standards, and to better associate standard algorithmic tasks to each of the three mentioned brainwave types. (4 pages)Design and implementation of efficient multiplier using Vedic mathematics
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0071
Multiplication is an important fundamental function in arithmetic operations. Multiplication-based operations such as Multiply and Accumulate(MAC) and inner product are among some of the frequently used computation Intensive Arithmetic Functions(CIAF) currently implemented in many Digital Signal Processing (DSP) applications such as convolution, Fast Fourier Transform(FFT), filtering and in microprocessors m its arithmetic and logic unit. Since multiplication dominates the execution tune of most DSP algorithms, so there is a need of high speed multiplier. Currently, multiplication time is still the dominant factor in determining the instruction cycle time of a DSP chip. The demand for high speed processing has been increasing as a result of expanding computer and signal processing applications. Higher throughput arithmetic operations are important to achieve the desired performance in many real-time signal and image processing applications . One of the key arithmetic operations in such applications is multiplication and the development of fast multiplier circuit has been a subject of interest over decades. Multiplier based on Vedic Mathematics is one of the fast and low power multiplier. Employing this technique in the computation algorithms will reduce the complexity, execution time, power etc. This vedic based multiplier is compared with binary multiplier(partial products method).A novel modulation classification for PSK and QAM signals in wireless communication
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0636
In this paper, we proposed a new modulation classification algorithm in AWGN channel using fourth order cumulants and improved clustering density spectrum. First, subtractive clustering algorithm is used to classify MPSK and MQAM. Then, a novel algorithm based on the density spectrum of digital signal constellations and cumulants is proposed to internally identify MQAM and MPSK respectively. The peak numbers of in-phase and quadrature density envelope are derived to classify MQAM based on haar wavelet transform. Compared with the existing methods, it is a simple solution with a smaller number of symbols and more modulation types. Simulation results prove the efficiency of the proposed classification algorithm.A combined interpolation method for waveform reconstruction in beacon transmitter detector
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0889
When beacon transmitter detector making measurements on high speed beacon signal, interpolation is required to reconstruct waveform from sampled waveform data for optimal waveform viewing. In this paper, the linear interpolation and sine interpolation are introduced and analyzed firstly. Then utilizing the characteristics of beacon transmitter detector, a combined interpolation method which consists of the linear interpolation and sine interpolation is proposed. Simulation results show that the proposed combined method has good waveform reconstruction performance and relatively low computational complexity. It is very suitable for implementation of waveform reconstruction in beacon transmitter detector.Audio fingerprinting based on local energy centroid
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0907
Audio fingerprint is an effective representation of an audio signal using low-level features and can be used to identify unlabeled audio based on its content. In this paper, we introduce a robust audio feature, local energy centroid (LEC), which can represent the energy conglomeration degree of the relative small region in the spectrum. Our audio fingerprint is generated based on the LEC feature which is conducive to enhance the robustness of system. In audio retrieval processing, an improved scoring strategy is proposed to resist the linear speed change. Experimental results show that the new fingerprinting system is quite robust in the present of noise and the proposed method can achieve satisfying recognition accuracy.Investigation on a NLOS error mitigation algorithm for TDOA mobile location
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0787
In typical Urban environment, non-Line-Sight (NLOS) propagation between the base station (BS) and mobile station (MS) became the main factor of the positioning error. As a result, the study on the mitigation of its negative influence becomes a focus. Base on Chan algorithm, this paper presents a TDOA mobile location algorithm, which can improve the positioning accuracy effectively. The positioning process includes NLOS error identification and its mitigation. First, the Wylie algorithm is used to identify the existence of NLOS. And then, the time of arrival (TOA) is update based on the difference of TOA and the distance between BS and MS. This coordinate of the MS is estimated by using Chan algorithm in the process of this distance calculating. Simulation results show that this algorithm can mitigate the NLOS error and improve the location accuracy in different environment effectually.An improved algorithm of synchronization based on maximum correlation for GSM signals
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0691
Several traditional algorithms of synchronization of GSM signal first discussed in this paper. They do not work well at low signal-noise-ratio. An improved algorithm based on maximum correlation is proposed in this paper. This paper compares and analyses the proposed algorithm with the traditional algorithm. Finally, a simulation has been taken to show the performance of different algorithm. The simulation shows that the proposed algorithm can conquer the strong interfere and synchronize accurately.Sensing, processing and application of EMG signals for HAL (Hybrid Assistive Limb)
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0463
Hybrid Assistive Limb (HAL) is an assistive technology device for supporting physically disabled persons by understanding the percentage of their disability. This work aims to design and develop a HAL based on Electromyogram (EMG) signals. The EMG signal is a biomedical signal that measures electrical currents generated by muscles. These signals can be used for clinical/biomedical applications if advanced methods for detection, decomposition, processing, and classification are available. The pattern of the EMG signal produced may differ depending on the activity of the muscle movement. Four types of biceps muscle activities are identified using the signal pattern generated from raw surface EMG data. Threshold detection method and pattern recognition method were carried out and it is found that pattern recognition method is more generalized method for classification as threshold method is user dependent. The overall classification rate of about (80-83) % obtained using LDA and a classification rate of more than 90% obtained using ANN. Control commands for a stepper motor used for driving artificial limb are developed from the classified EMG signal and stepper motor control is achieved through computer parallel port.Tunable and reconfigurable microwave photonic signal processors
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.1357
Recent developments in microwave photonic signal processing featuring tunability and reconfigurablity are presented in the paper, with emphasis on the realisation of multi-tap microwave photonic filters, and programmable signal processing functions based on photonic approaches. (2 pages)Developing a disaster surveillance system based on wireless sensor network and cloud platform
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0770
Typically, today's WSN disaster surveillance system operates poorly in its accuracy and timeliness and can only detect a single type of disasters. This owes largely to the congestion brought about by excessive communication traffic and the processing limitation of the server which dramatically restrict the development of disaster surveillance systems. In order to solve these problems, this paper proposes a new scheme in improving the traditional disaster surveillance systems. At the data collection and transmission layer, orthogonal neural network algorithm, which is based on the wavelet transform, is introduced to promote the surveillance accuracy and reduce the network congestion. At the data storage and computing layer, cloud storage and distributed parallel computing are used to overcome the limitation of the previous storage and computation. At last, the paper gives the concrete implementation plan and verifies the superiority of the system.Decreasing the influence of dispersive wave modes in long-range ultrasonic rail testing using wavelets
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0617
The sensitivity and the resolution of long-range ultrasonic testing (LRUT) are significantly limited by the presence of dispersive wave modes, commonly inherent to the acquired ultrasonic signals. This paper presents a signal processing technique based on the discrete wavelet transform (DWT) for reducing the effect of dispersive wave modes in LRUT of rails. A comparative study of different type of wavelet, thresholding procedures and threshold selection rules is presented. The proposed concept has been evaluated in the presence of high level of additive dispersive waveform at signal to noise ratio (SNR) from -20dB to 20dB. The results show that the effect of dispersion can be reduced in great extent even in the case of extremely high SNR level. (6 pages)Effective channel estimation for sparse multipath OFDM systems
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0628
Coherent detection and demodulation need channel state information at receivers for orthogonal frequency division multiplexing systems. Conventional channel estimations, such as least squares (LS), are widely adopted under the assumption of rich multipath. Recently, numerous physical measurements have verified that many wireless multipath channels encountered in practice tend to exhibit sparse structures. Exploiting the inherent sparsity, a novel channel estimation method based on compressive sensing is proposed, which reduces the number of pilots so as to improve the bandwidth efficiency. Simulation results confirm that the proposed method has a 5-dB lower mean square error in channel estimation when compared to the conventional approach. In addition, the complexity of the proposed method is acceptable.A modified ESPRIT algorithm for signal DOA estimation
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0647
We propose a new algorithm to estimate the 2-D direction of arrival (DOA) of narrowband sources lying in the far field of the array. The algorithm requires no reference signal, which consists of two stage processes. The algorithm of the first stage using the method of ESPRIT acquires data. At the second stage, the method using the space-time DOA matrix method to processing the data. The method transfers the observed data from space domain to 2-D space-time domain by exploiting the cross-correlation of the array outputs. Simulation results show a good improvement in processor performance.DOA estimation in MIMO radar based on coherent signal-subspace method [signal read signal]
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0840
MIMO radar in this paper uses sparse-array to transmit the FMCW signals of multiple carrier frequencies, and an array to receive the echoes. Due to transmit signals of multiple carrier frequencies, the Doppler frequency of the received signals after separated is not in a Doppler cell, and then the traditional supper-resolution algorithms work ineffectively, the parameters of the target can't be obtained. One method is presented in this paper. Firstly the data of different frequency is transformed into the data of the same frequency using focusing transformation, and then the spatial spectrum estimation algorithms are applied. The simulation results indicate the validity of the methods presented in this paper.Performance study of multi-way wireless relay network coding algorithm based on precoding technology
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0641
In order to save the frequency resource and have better anti-noise characteristics in multi-way relay wireless communication system, this paper proposes three adaptive network coding algorithms based on precoding technology which meet transmission capacity maximization of communication system. The three network coding algorithms proposed in this paper are the Beamforming (BM-NC), Space-multiplexing(SM-NC) and the Space-time (ST-NC) network coding. We also contrast the anti-noise performance of three network coding algorithms by communication system simulation experiment.Target monitoring in wireless sensor networks using compressive sensing
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0304
The events are relatively sparse compared with the number of sources in wireless sensor networks. In order to reduce deployment cost, the number of sensors is limited, because sensor has limit energy, so not all the sensors are turned on all the time. In this paper, a model is introduced to formulate the problem of target detection in wireless sensor networks through a compressive sensing method. The number of wake-up sensors can be greatly reduced accompany with the number of sparse events decrease; sparse event is much smaller than the total number of sources. We use binary nature to indicates a target is found or not, and use OPM algorithm to recovery sample signal .Finally, we analyze and compare the performance of the model through compressive sensing algorithms at different condition. Simulation result show that the sampling rate can reduce accompany with the target reduce without sacrificing performance. With further decreasing the sampling rate, the performance is gradually reduced. (4 pages)A de-noising method for heart sound signal using Otsu's threshold selection
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0848
In this research, Otsu's method methods is quoted and applied to de-noise heart sounds so that unwanted noises can be separated from a combined set of noises extracted through an electronic stethoscope. The noise was analyzed by applying a random but suitable threshold section method, the unwanted noise was reduced and the useful sound was reconstructed. The initial result shows that the method applied is effective and the reconstructed signal appears to be providing a better quality of heart sound.Characterisation of ballast materials in trackbed using ground penetrating radar: Part 1
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0593
In recent years the use of high frequency GPR antennas such as the 2GHz horn antenna have become popular for railway trackbed evaluation due to their ability to help determine the extent of fouling within the ballast layer. Fouling of the ballast affects both its strength and drainage properties. The theory is based on the scattering behaviour of GPR signals in an inhomogeneous media, comprising evenly distributed particles and air voids. Whilst GPR has been successfully implemented as a tool for mapping ballast quality, the relation between the GPR scattering response and the physical properties of the ballast and fouling materials have not been examined and studied in detail up until now the method has been mainly empirical, based on measured correlations. This paper conducts an investigation of the GPR scattering response to the railway ballast aggregate layer by providing a comprehensive study of factors affecting the radar signal including; ballast grading (particle size distribution), particle shape, void size and the electromagnetic properties of the ballast (dielectric, conductivity, magnetic permeability). Sample analysis, numerical simulations, laboratory tests and real-world data collection have been conducted in this research. Detailed analysis and discussions are provided on factors contributing to the observed signal scattering and attenuation. This is the first in a series of papers looking at the influence of various factors on the response of GPR within ballasted trackbed. (8 pages)New coordinated beamforming scheme for multi-cell multi-user MIMO systems
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0625
As the development of next-generation wireless broadband cellular networks, base station (BS) cooperation has become a promising tool to increase the per-cell spectral efficiency as well as cell-edge user throughput. In this paper, we introduce a new multi-cell cooperation strategy, where each cooperating BS simultaneously serves two co-channel users, one from the cell edge and the other from the cell center. Three distributed coordinated beamforming schemes together with user pairing for the considered cooperative multi-cell multi-user MIMO system are proposed. Simulation results show that the signa- to-leakage-and-noise ratio (SLNR) based scheme and the ZF-SLNR scheme are able to considerably improve both the system total throughput and edge user throughput.PQ events classification and detection - a survey
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0412
This paper carries out a comprehensive review of various techniques used in the recent years in PQ event classification. Within this context, artificial intelligence and optimization techniques as well as their fusion have been reviewed in the field of PQ. The important techniques used in past are also provided in tabular form. Although this review cannot be collectively exhaustive, it may be considered as a valuable guide for researchers who are interested in the domain of PQ and wish to explore the opportunities offered by these techniques for further improvement in the same field. It is also analysed that still more research is to be done for online analysis of PQ events.SpaceAnnotator: a high precision location based asset management system in indoor environment
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0748
Asset management is urgently needed in supply chain which requires to solve two basic problems 1) what assets do we have; and 2) where they are? Existing methods exploit barcode and RFID technologies to retrieve the information and quantity of assets. However, the location of asset is still hard to obtain for the lack of suitable location technologies. In this paper, a high precision location based asset management system named SpaceAnnotator is proposed. SpaceAnnotator is implemented based on TOA positioning method using Ultrasound and RF signals. Leveraging the centimeter level positioning accuracy provided by the positioning system, SpaceAnnotator maps the IDs of objects to their locations. Based on the location information, location based service (LBS) in provided for asset management. Compared with conventional location based asset management system, SpaceAnnotator works well even in managing small volume objects for its high accuracy.A high speed turbo decoder implementation for CPU-based SDR system
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0622
More and more CPU-based SDR systems appear in recent two years. Such system requires high speed real-time signal processing. In this paper, we present our effort on the speed optimization of Turbo decoder, the most computation-demanding module in all baseband modules. We jointly consider the algorithm parallelism and the processor architecture. Single Instruction Multiple Data (SIMD) instruction is used for software implementation. The evaluation results show that this proposed design can achieve a maximum of 124 Mbps throughput for single Soft Input Soft Output (SISO) module with Max-Log-MAP algorithm.Soft spatial-frequency reuse based on minimum interference leakage
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0673
Coordinated Scheduling/Beamforming is proposed as an attractive technology to enhance the cell edge performance. However, the performance gain comes at the cost of explicit exchange of Channel State Information (CSI) and scheduling/ precoding information over the backhaul links. In this paper, a decentralized scheme named as soft spatial-frequency reuse scheme is proposed. Different from centralized schemes, which mitigate interference from other cells, SSFR minimizes the interference leakage to adjacent cells. Compared with the traditional interference coordination scheme, the SSFR could improve the cell-edge throughput by 30%, and total cell throughput by 2-10%.An improved complementary matching pursuit algorithm for compressed sensing signal reconstruction
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.1497
The complementary matching pursuit (CMP) algorithm is analogous to the classical matching pursuit (MP), but performs the complementary action. It deletes (N-1) atoms from the sparse approximation at each iteration and keeps only one atom while other algorithms select one atom and add it into the sparse approximation, which makes CMP have better reconstruction quality. However, remaining only one atom at each iteration costs more time in CMP. In this work, an improved CMP algorithm is proposed to shorten the reconstruction time. The proposed CMP algorithm selects more than one atoms at each iteration following a certain rule from Sparsity Adaptive Matching Pursuit(SAMP). In which, the number of selected atoms changes with Adaptive Size (AS) every iteration. The experiment results show that the improved method could achieve better reconstruction quality with less time than the Gradient Pursuit (GP), Orthogonal Matching Pursuit (OMP) and original CMP.A new PAPR reduction scheme for OFDM signals based on GDFT signal processing theory
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0634
Peak-to-average-power ratio (PAPR) is a key design concern of an orthogonal frequency division multiplexing (OFDM) system as it determines the system's power efficiency. In this paper, we propose a PAPR reduction method for an OFDM system based on the Generalized Discrete Fourier Transform (GDFT) signal processing theory proposed by AH N. Akansu. GDFT is a generalized framework for DFT with nonlinear phase by exploiting the phase space. There are infinitely many possible GDFT sets available in the phase space with constant power where one can design the optimal basis for the desired figure of merit. Our proposed GDFT-OFDM combines the advantage of GDFT with the traditional OFDM system, providing a new way to solve the problem of PAPR reduction in OFDM system. In simulation results, the PAPR performance of GDFT-OFDM is proved to be well improved with different form of GDFT.Improved UWB pulse shaping method based on Gaussian derivatives
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0925
In order to maximize the power spectrum utilization (PSU) while satisfying the Federal Communications Commission (FCC) emission mask, an improved two-stage ultra-wideband (UWB) pulse shaping method based on Gaussian derivatives is presented. Firstly, sub-pulses are designed by optimal combination of Gaussian derivatives over specific sub bands with the condition of maximizing the PSU allowed by emission mask. Secondly, the full band UWB pulse is shaped by the combination of the outputs of parallel band-pass filters (BPFs) bank with the sub pulses as inputs to these BPFs. Simulation results show that the UWB pulse shaped not only meets the FCC emission mask in full band, but also uses the limited power capacity more effectively, improving the PSU rate to enhance the performance of received UWB signal processing possibly. The proposed idea of sub band pulse design may be useful in narrow band interference mitigation as well in application of UWB technology.DOA estimation algorithm of MIMO system
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0649
In this paper, we propose a method of direction of arrival (DOA) estimation which is called complex spatial specturm method (CSM). Advantages and disadvantages of the multiple signal classification (MUSIC) algorithm and the Reciprocal Weighted of Signal subspace principal eigenvalue Projection (RWSP) algorithm are discussed in the paper. By combing the advantages of two algorithms, the information of signal subspace and noise subspace are used in CSM. The feasibility of CSM which uses spatial spectrum estimation is proved theoretically. Simulation results indicate that the CSM is a high resolution and robustness algorithm for resolving multiple incoherent and coherent signals that are incident on an array of antenna.A novel implementation of timing synchronization based on convolution for GBPS OFDM trial system
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0792
In this paper, a novel timing synchronization algorithm and its implementation scheme are presented. Although conventional synchronization algorithm with correlation method has good performance, it is difficult to implement in hardware due to its high resource consumption and long capture time. The proposed method focuses on addressing these problems for practical application in orthogonal frequency division multiplexing (OFDM) systems. Instead of correlation, the novel algorithm based on preamble adopts convolution to accelerate the frame capture procedure. Implemented on a Virtex-5 series Xilinx FPGA, at least 85% of block RAMs are saved while comparable or even better performance is achieved by using the algorithm. Finally, the scheme is proven stable and efficient in a Gbps OFDM trial system.