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Vehicular Technology, IEEE Transactions on

Issue 4 • Date July 2007

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Displaying Results 1 - 25 of 45
  • Table of contents

    Page(s): C1 - C4
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  • IEEE Transactions on Vehicular Technology publication information

    Page(s): C2
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  • Effects of Bandwidth on Observable Multipath Clustering in Outdoor/Indoor Environments for Broadband and Ultrawideband Wireless Systems

    Page(s): 1913 - 1923
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (795 KB) |  | HTML iconHTML  

    A multipath-clustering phenomenon, which is caused by the fact that scatterers tend to group together in realistic environments, has a significant impact on the channel capacity. For a band-limited system, due to the limitation of the signal time resolution, observable multipath-clustering is affected not only by propagation environments but also by the signal bandwidth. Since a larger bandwidth gives better time resolution, it is possible to observe more multipath components and, therefore, stronger clustering effects. In this paper, a new method based on the Delta-K model for multipath times of arrival (TOAs) is proposed to investigate and quantify the effect of signal bandwidth on observable multipath clustering. Furthermore, to completely characterize the time dispersion characteristics of the channel, a statistical model using a power ratio, a decay constant, and the Rician factor to describe multipath averaged power decay and amplitude fading is proposed. Newly derived formulas are given to relate the model parameters of a wideband signal, including those of the multipath TOA, averaged power decay, and amplitude fading, to those of a narrowband signal. The channel parameter estimation methods have been extensively validated by comparing the computed channel parameters with the ones extracted from the measured channel responses of 1.95 and 2.44 GHz broadband radios in metropolitan and suburban areas, and of 3-5 GHz ultrawideband signals in indoors. View full abstract»

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  • Simplified Spatial Correlation Models for Clustered MIMO Channels With Different Array Configurations

    Page(s): 1924 - 1934
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (696 KB) |  | HTML iconHTML  

    An approximate spatial correlation model for clustered multiple-input multiple-output (MIMO) channels is proposed in this paper. The two ingredients for the model are an approximation for uniform linear and circular arrays to avoid numerical integrals and a closed-form expression for the correlation coefficients that is derived for the Laplacian azimuth angle distribution. A new performance metric to compare parametric and nonparametric channel models is proposed and used to show that the proposed model is a good fit to the existing parametric models for low angle spreads (i.e., smaller than 10deg). A computational-complexity analysis shows that the proposed method is a numerically efficient way of generating the spatially correlated MIMO channels. View full abstract»

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  • Wiener-System Subspace Identification for Mobile Wireless mm-Wave Networks

    Page(s): 1935 - 1948
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (755 KB) |  | HTML iconHTML  

    We discuss the feasibility of wireless terahertz communications links deployed in a metropolitan area and model the large-scale fading of such channels. The model takes into account reception through direct line of sight, ground and wall reflection, as well as diffraction around a corner. The movement of the receiver is modeled by an autonomous dynamic linear system in state space, whereas the geometric relations involved in the attenuation and multipath propagation of the electric field are described by a static nonlinear mapping. A subspace algorithm in conjunction with polynomial regression is used to identify a single-output Wiener model from time-domain measurements of the field intensity when the receiver motion is simulated using a constant angular speed and an exponentially decaying radius. The identification procedure is validated by using the model to perform q-step ahead predictions. The sensitivity of the algorithm to small-scale fading, detector noise, and atmospheric changes are discussed. The performance of the algorithm is tested in the diffraction zone assuming a range of emitter frequencies (2, 38, 60,100,140, and 400 GHz). Extensions of the simulation results to situations where a more complicated trajectory describes the motion of the receiver are also implemented, providing information on the performance of the algorithm under a worst case scenario. Finally, a sensitivity analysis to model parameters for the identified Wiener system is proposed. View full abstract»

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  • Time-Varying MIMO Channels: Parametric Statistical Modeling and Experimental Results

    Page(s): 1949 - 1963
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (938 KB) |  | HTML iconHTML  

    Accurate characterization of multiple-input multiple-output (MIMO) fading channels is an important prerequisite for the design of multiantenna wireless-communication systems. In this paper, a single-bounce two-ring statistical model for the time-varying MIMO flat fading channels is proposed. In the model, both the base and mobile stations are surrounded by their own ring of scatterers. For the proposed model, a closed-form expression for the spatio-temporal cross-correlational function between any two subchannels is derived, assuming single-bounce scattering. The new analytical expression includes several key physical parameters of interest such as the mean angle-of-departure, the mean angle-of-arrival, the associated angle spreads, and the Doppler spread in a compact form. The model includes many existing correlation models as special cases. Its utility is demonstrated by a comparison with collected MIMO data in terms of the spatio-temporal correlations, level crossing rate, average fade duration, and the instantaneous mutual information. View full abstract»

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  • Analytical Evaluation and Optimization of the Analog-to-Digital Converter in Software Radio Architectures

    Page(s): 1964 - 1970
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (303 KB) |  | HTML iconHTML  

    The software radio concept is a topic of widespread interest in wireless cellular systems. Due to the high sampling ratio and quantization requirements, the analog-to-digital converter (ADC) is used as a key component of any software radio architecture. In this paper, we present an analytical tool for evaluating the quantization requirements within the ADC that is used in software radio architectures. For this purpose, we take advantage of the Gaussian behavior of the multiband/multiuser signal at the input of the wideband ADC and employ results on Gaussian signals and memoryless nonlinearities. This characterization is then used for the performance evaluation and optimization of different quantization characteristics. View full abstract»

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  • Analysis of an Adaptive Wideband Duplexer With Double-Loop Cancellation

    Page(s): 1971 - 1982
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (631 KB) |  | HTML iconHTML  

    An active wideband duplexer reduces the need for multiple switched duplexing filters in multiband software radio implementations. The technique is based on a two-step isolation process: 1) a low isolation device and 2) an active double-loop canceling technique that leads to two nulls, one at the desired receive frequency and the other at the transmit frequency. Two cancellation paths generate replicas of the residual transmitter interference signal and noise signal for subtraction from the output of the low isolation device. The feasibility of wideband cancellation mainly depends on the duplexing offset and the operating range of delays in the main path and the cancellation paths. The adjustment range of the coefficients in the cancellation path puts further constraints on these delays. This paper presents a theoretical analysis of double-loop cancellation using geometrical representations. The delay boundaries are derived for a given adjustment range of the vector attenuators (coefficients) used in the cancellation paths. The relationship between cancellation bandwidth and residual cancellation level is shown to be linear (6 dB/octave) and related to the loop delays and the duplexing offset. View full abstract»

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  • Occupant Classification Using Range Images

    Page(s): 1983 - 1993
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (429 KB) |  | HTML iconHTML  

    Static occupant classification is an important requirement in designing so-called "smart airbags." Systems for this purpose can be either based on pressure sensors or vision sensors. Vision-based systems are advantageous over pressure-sensor-based systems as they can provide additional functionalities like dynamic occupant-position analysis or child-seat orientation detection. The focus of this paper is to evaluate and analyze static occupant classification using a low-resolution range sensor, which is based on the time-of-flight principle. This range sensor is advantageous, since it provides directly a dense range image that is independent of the ambient illumination conditions and object textures. Herein, the realization of an occupant-classification system, using a novel low-resolution range image sensor, is described, methods for extracting robust features from the range images are investigated, and different classification methods are evaluated for classifying occupants. Bayes quadratic classifier, Gaussian mixture-model classifier, and polynomial classifier are compared to a clustering-based linear-regression classifier using a polynomial kernel. The latter one shows improved results compared to the first-three classification methods. Full-scale tests have been conducted on a wide range of realistic situations with different adults and child seats in various postures and positions. The results prove the feasibility of low-resolution range images for the current application. View full abstract»

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  • Robust Active Vibration Control for Rail Vehicle Pantograph

    Page(s): 1994 - 2004
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (639 KB) |  | HTML iconHTML  

    This paper deals with vibration control for a light rail vehicle's pantographs. The concepts of force cancellation, skyhook damper, and contact wire-following spring are jointly applied to constitute an effective controller for vibration suppression. Performance of the control system is evaluated on the basis of variations of displacement and acceleration between the pantograph and contact wire. An active control law is developed by means of a linear quadratic regulator design to derive a stabilizing control law for the pantograph system with the time-varying contact force between the pantograph shoe and catenary. A systematic optimization process with Pareto set and variable weights for the design of active suspension parameters of the pantograph using a constrained multiobjective evolutionary algorithm is developed. Extensive simulations are well performed to verify our proposed design. View full abstract»

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  • Negative Impedance Stabilizing Pulse Adjustment Control Technique for DC/DC Converters Operating in Discontinuous Conduction Mode and Driving Constant Power Loads

    Page(s): 2005 - 2016
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (563 KB) |  | HTML iconHTML  

    Multiconverter power-electronics-based power systems are being increasingly used in advanced vehicles. Stability of these power electronics-intensive systems is a significant design consideration because of the potential for negative impedance instability. In this paper, in order to mitigate the problem of negative impedance instability, pulse adjustment, which is a novel fixed frequency digital control technique for converters operating with constant power loads (CPLs), is presented. This novel digital control approach treats the converter as a digital system and achieves output voltage regulation by choosing high- and low-power pulses instead of using conventional pulsewidth modulation scheme. A comparator compares the actual output voltage with the reference voltage and then switches between the appropriate states. Therefore, the digital control task is to deliver the right amount of energy to the converter by right numbers of state operations so that the average power delivery matches the required power. It needs few logic gates and comparators to implement this digital control, thus making it extremely simple and easy to develop using low-cost application specific integrated circuits. It is simple, cost effective, and dynamically fast. In this paper, a model to analyze the dc/dc buck-boost converter that is controlled by the pulse adjustment approach in the discontinuous conduction mode is derived. Stability of the buck-boost converter driving CPLs is analyzed using the introduced model. Furthermore, comprehensive sensitivity analyses of applying the pulse adjustment method to control dc/dc converters that are loaded by CPLs are presented. In addition, this paper gives design considerations to assess performance and stability robustness of the pulse adjustment method to control buck-boost converters that are loaded by CPLs. Analytical, simulation, and experimental results are presented to describe and verify the proposed technique. View full abstract»

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  • High-Intensity Contact Opening Under 36-V DC Voltage Application for Mild Hybrid Vehicles

    Page(s): 2017 - 2027
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1771 KB) |  | HTML iconHTML  

    This paper concerns the study of contact opening under dc voltage in the case of high-intensity current (a few hundred amperes). The application fields are mainly automotive and aeronautical systems. An experimental device has been designed in order to study the opening of contacts under various conditions. The influence of several parameters on contact opening is studied. These are the following: the opening velocity, the current intensity through the closed contact, the nature of the contact materials (Ag, Ag-12wt%SnO2), the value of the inductance in the electrical circuit. The measured parameters characterizing the opening phase are as follows: the arc duration, the value of the electrode gap when the arc extinguishes, the arc energy, the maximal value of the contact voltage during the opening phase, and the electrode erosion. The study of the erosion is achieved with the help of a 3-D profllometer enabling the measurement of mass transfer and, for instance, of the amount of molten or evaporated metal. View full abstract»

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  • Nonparametric Approaches for Estimating Driver Pose

    Page(s): 2028 - 2041
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (678 KB) |  | HTML iconHTML  

    To better understand driver behavior, the Federal Highway Administration and the National Highway Traffic Safety Administration have collected several thousands of hours of driver video. There is now an immediate need for devising automated procedures for analyzing the video. In this paper, we look at the problem of estimating driver pose given a video of the driver as he or she drives the vehicle. A complete system is proposed to perform feature extraction and classification of each frame. The system uses a Fisherface representation of video frames and a nearest neighbor and neural network classification scheme. Experimental results show that the system can achieve high accuracy and reliable performance. View full abstract»

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  • Blind Channel Estimation for Orthogonal STBC in MISO Systems

    Page(s): 2042 - 2050
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (277 KB) |  | HTML iconHTML  

    This paper presents a closed-form blind channel estimation scheme for orthogonal space-time block codes in multiple-input single-output (MISO) systems, with specific focus on Alamouti's code for two transmit antennas. The channel matrix is estimated from the eigenvalue decomposition of the fourth-order cumulant matrix of the received signal. Unlike previous blind estimation schemes for MISO systems, the proposed algorithm is tested with block and slowly fading channels. The proposed scheme performs very well in both cases. A single pilot tuple is required to correctly assign the estimated to the actual channels and to resolve the sign ambiguity common to all blind estimators. It is shown that this scheme outperforms the only other available blind channel estimation scheme for this scenario. To achieve good performance in terms of bit error rate, 100-300 sample points are sufficient to provide accurate channel estimates. The main disadvantage of the proposed scheme is the complexity associated with the estimation of fourth-order cumulants. This complexity is reduced by exploiting the symmetry inherent in the cumulant matrix. View full abstract»

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  • A Unified Analysis of Diversity Exploitation in Multicarrier CDMA

    Page(s): 2051 - 2062
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (337 KB) |  | HTML iconHTML  

    Since the introduction of multicarrier code-division multiple access (MC-CDMA), several publications have presented various detection concepts for efficient and robust multiuser communications in the up- and downlink. System concepts, which either exploit channel knowledge at the transmitter or at the receiver, have been investigated. The approach, which exploits channel knowledge at the transmitter and at the receiver simultaneously, referred to as combined-equalization, is a new approach that targets a common optimization of data transmission and reception. In this paper, we introduce a unified analysis for optimally exploiting diversity. We apply this analysis exemplarily to MC-CDMA systems exploiting any of the aforementioned concepts. It should be noted that this analysis could be applied to numerous other systems that exploit diversity. The presented approach analytically derives the theoretical lower performance bounds for pre-, post-, and combined-equalization achievable with MC-CDMA in up- and downlink. This fundamental investigation of lower bounds will serve as a benchmark for future optimization of MC-CDMA in multiuser scenarios. Moreover, we exemplarily present multiuser performance results with combined-equalization for the uplink which approach the lower bound derived in this paper. View full abstract»

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  • On the Optimal Sequences and Total Weighted Square Correlation of Synchronous CDMA Systems in Multipath Channels

    Page(s): 2063 - 2072
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (305 KB) |  | HTML iconHTML  

    We generalize the total square correlation and the total weighted square correlation (TWSC) for a given signature set used in synchronous code division multiple access (S-CDMA) systems. We define the extended TWSC measure for multipath channels in the presence and the absence of the colored noise. The main results of this paper are the following: 1, the necessary and sufficient conditions of the received Gram matrix to maximize the sum capacity in the presence of multipath; 2, the conditions on the channel such that the received multipath sequences in the presence of the colored noise are Welch bound equality (WBE) sequences; 3, a decentralized method for obtaining generalized WBE sequences that minimize the TWSC in the presence of multipath and colored noise. Using this method, the optimal sequences, which achieve sum capacity for overloaded S-CDMA systems, in the presence of multipath are obtained. Numerical examples that illustrate the mathematical formalism are also included. View full abstract»

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  • On Linear Predictive Detection for Communications With Phase Noise and Frequency Offset

    Page(s): 2073 - 2085
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (716 KB) |  | HTML iconHTML  

    In this paper, by applying the concept of linear prediction, which is widely used for fading channels, to phase- uncertain communications, we generalize existing linear predictive detection algorithms for transmission over channels with phase noise and frequency offset. This approach leads to the derivation of detection algorithms, which are referred to as phasor linear predictive (pLP), for trellis-based maximum a posteriori (MAP) sequence detection (based on the Viterbi algorithm) and MAP symbol detection: trellis-based (using the forward- backward algorithm) and graph-based (using the sum-product algorithm). The effectiveness of the proposed pLP detection algorithms is evaluated for several communication schemes. The derived algorithms outperform previously appeared finite- memory detection solutions in terms of robustness against fast channel dynamics. Moreover, the proposed detection strategy lends itself to attractive extensions to adaptive schemes. View full abstract»

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  • Time-Division-Based Cyclic Scheduling for UMTS High-Speed Downlink Shared-Channels

    Page(s): 2086 - 2094
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (480 KB) |  | HTML iconHTML  

    Third Generation Partnership Project working group proposes the high-speed downlink packet access to speed up downlink transmission for the universal mobile telecommunication system, where the time-division-based high-speed downlink shared-channel (HS-DSCH) approach is adopted. Our previous work proposed the shared-channel assignment and scheduling (SCAS) scheme to efficiently schedule the DSCH to serve different connections, which guarantees the requested transmission rate for each connection. However, limitations exist in the SCAS scheme: 1) the requested transmission rates of connections must be two's power numbers of the basic transmission rate and 2) all served connections should be rescheduled while a new request is granted, which introduces extra rescheduling overhead to the system. This paper proposes the elastic shared-channel assignment and scheduling (eSCAS) scheme to overcome these limitations. We formally prove the correctness of the eSCAS scheme. An analytical model and simulation experiments are conducted to compare the performance for eSCAS and SCAS. Our study shows that eSCAS can significantly improve the acceptance rate for new connections without increasing the rescheduling overhead. View full abstract»

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  • Channel Assignment and Time Sharing for Multiple Access in Multicarrier Communication Systems

    Page(s): 2095 - 2107
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (294 KB) |  | HTML iconHTML  

    In this paper, we present a general 2-D multiple-access scheme, namely, code time division multiple access (CTDMA), on the downlink of multicarrier communication systems. CTDMA combines the idea of CDMA in the code domain and TDMA in the time domain. We consider suitable resource allocation strategies with our CTDMA scheme in the code domain and the time domain jointly. Under the total transmission-power minimization criterion, we propose a near optimal approach to allocate codes and transmission time to users appropriately, while the data rate of each user is guaranteed. To reduce the computational complexity, we also give some simplified suboptimal approaches for certain types of systems, namely, the one-to-one approach for the fully loaded system and the multiple-to-one approach for the nonfully loaded systems. To check the differences between our approaches and the optimal allocation strategy, we derive a pair of lower and upper bounds on the optimal resource allocation solution. Simulation results show that major improvement can be obtained by the near optimal approach, while the suboptimal approaches only cause minor performance degradation. We also show that our approaches will all converge to the lower bound as well as the optimal allocation solution, when the system size increases. View full abstract»

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  • Noncoherent Constant False-Alarm Rate Schemes With Receive Diversity for Code Acquisition Under Homogeneous and Nonhomogeneous Fading Circumstances

    Page(s): 2108 - 2120
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (389 KB) |  | HTML iconHTML  

    In this paper, we address the cell averaging (CA), greatest of (GO), and smallest of (SO) constant false-alarm rate (CFAR) processors for code acquisition in a homogeneous and a nonhomogeneous environment. The performance characteristics of the CA, GO, and SO processors are analyzed and compared when receiving antenna diversity is employed in the pseudonoise code acquisition of direct-sequence code-division multiple-access systems. From the simulation results, it is observed that the GO CFAR scheme has the best performance in a nonhomogeneous environment and has almost the same performance as the CA CFAR scheme in a homogeneous environment. View full abstract»

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  • Log-Shifted Gamma Approximation to Lognormal Sum Distributions

    Page(s): 2121 - 2129
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (978 KB) |  | HTML iconHTML  

    This paper proposes the log-shifted gamma (LSG) approximation to model the sum of M lognormally distributed random variables (RVs). The closed-form probability density function of the resulting LSG RV is presented, and its parameters are directly derived from those of the M individual lognormal RVs by using an iterative moment-matching technique without the need for curve fitting of computer-generated distributions. Simulation and analytical results on the cumulative distribution function (cdf) of the sum of M lognormal RVs in different conditions indicate that the proposed LSG approximation can provide better accuracy than other lognormal approximations over a wide cdf range, especially for large M and/or standard deviation. View full abstract»

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  • Self-Matching Space-Time Block Codes for Matrix Kalman Estimator-Based ML Detector in MIMO Fading Channels

    Page(s): 2130 - 2142
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (409 KB) |  | HTML iconHTML  

    This paper presents a unifying framework for designing a joint channel-estimation-and-data-detection (CE/DD) scheme and space-time block code (STBC) that improves the performances in a multiple-input-multiple-output (MIMO) slow flat Rayleigh fading channel. Modeling the channel using the continuous-fading model, a matrix state-space model, which naturally represents the temporal and spatial dimensions of a MIMO system, is introduced. A consistent and novel matrix CE/DD scheme is developed using a matrix Kalman filter and a matrix normalized-innovations-based maximum-likelihood detector. In MIMO CE/DD in multiplicative fading, symmetric STBCs (S-STBCs) cause isometric data sequences, which lead to a detection error floor. Motivated by the minimization of the probability of error, two asymmetric STBCs are introduced to be used with these S-STBCs to mitigate isometry. To further improve detection performance, a self-matching STBC (SM-STBC), which mitigates isometry using asymmetry, improves estimation performance using training, and improves detection performance by adapting its code properties, is introduced. This SM-STBC generalizes a limited version that was previously proposed. A comprehensive analysis, which is supported by some simulation studies, indicates that the proposed framework of transceiver and STBC designs offers excellent detection performance. View full abstract»

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  • Minimum Error-Rate Linear Dispersion Codes for Cooperative Relays

    Page(s): 2143 - 2157
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (335 KB) |  | HTML iconHTML  

    Cooperative diversity systems have recently been proposed as a solution to provide spatial diversity for terminals where multiple antennas are not feasible to be implemented. As in multiple-input-multiple-output systems, space-time codes can be used to efficiently exploit the increase in capacity provided in cooperative diversity systems. In this paper, we propose a two-layer linear dispersion (LD) code for cooperative diversity systems and derive a simulation-based optimization algorithm to optimize the LD code and power allocation in terms of block error rate. The proposed code design paradigm can obtain optimal codes under arbitrary fading statistics. Performance comparisons are made to other cooperative diversity schemes. The effect that distances between source, relays, and destination terminals have on the energy allocation between the broadcast and cooperative intervals is also studied. Cooperative diversity, gradient estimation, linear dispersion (LD) codes, multiple-input-multiple-output (MIMO), stochastic approximation. View full abstract»

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  • Iterative Methods for Cancellation of Intercarrier Interference in OFDM Systems

    Page(s): 2158 - 2167
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (797 KB) |  | HTML iconHTML  

    We consider orthogonal frequency-division multiplexing systems with intercarrier interference (ICI) due to insufficient cyclic prefix and/or temporal variations. Intersymbol interference (ISI) and ICI lead to an error floor in conventional receivers. We suggest two techniques for the equalization of ICI. The first, called "operator-perturbation technique" is an iterative technique for the inversion of a linear system of equations. Alternatively, we show that serial or parallel interference cancellation can be used to drastically reduce the error floor. Simulations show that, depending on the SNR and the origin of the ICI, one of the schemes performs best. In all cases, our schemes lead to a drastic reduction of the bit error rate. View full abstract»

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  • Analysis of Multiantenna Architectures for Non-LOS Mobile-to-Mobile Communications in Cochannel Interference

    Page(s): 2168 - 2179
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1122 KB) |  | HTML iconHTML  

    The performance of multiantenna receivers in cochannel interference is investigated for narrowband links in a non-line-of-sight mobile-to-mobile channel. Channel impairments include Doppler spread and angular spread originating from scatterers in the vicinity of both the transmitter and the receiver. The analysis employs a two-ring scattering model and compares the performance of a sectored system employing selection combining (SC) to the performance of adaptive arrays implemented with both omnidirectional antennas and sectored antennas. Performance is estimated for environments with cochannel interference and is measured in terms of output signal-to-interference-plus-noise ratio (SINR). An ensemble of random scattering realizations is utilized in the analysis to estimate the average output SINR. The results demonstrate the improved performance offered by adaptive arrays over sectored systems with SC. Configurations involving both SC and adaptive array processing were also evaluated and found to yield improvements over conventional adaptive array architectures. View full abstract»

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Aims & Scope

IEEE Transactions on Vehicular Technology covers land, airborne, and maritime mobile services, vehicular electrotechnology, equipment, and systems identified with the automotive industry.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Yuguang Michael Fang
University of Florida