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Vehicular Technology, IEEE Transactions on

Issue 4 • Date July 2008

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Displaying Results 1 - 25 of 70
  • Table of contents

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

    Page(s): C2
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    Freely Available from IEEE
  • Characterizing Temporal SNR Variation in 802.11 Networks

    Page(s): 2002 - 2013
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (488 KB) |  | HTML iconHTML  

    The analysis and design of wireless medium access control (MAC) protocols, coding schemes, and transmission algorithms can significantly benefit from an understanding of the channel quality variation. We attempt to represent channel quality variation using a finite-state birth-death Markov model. We outline a method to compute the parameters of the model based on measured traces obtained using common wireless chipsets. Using this Markov chain, we statistically evaluate the performance based on the channel quality, long-term correlations, and burst length distributions. Such a model significantly performs better than a traditional two-state Markov chain in characterizing 802.11 networks while maintaining the simplicity of a birth-death model. We interpret the variation of the model parameters across different locations and different times. A finite-state stationary model is amenable to analysis and can substantially benefit the design of efficient algorithms and make simulations for wireless network protocols faster. View full abstract»

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  • The 5-GHz Airport Surface Area Channel—Part I: Measurement and Modeling Results for Large Airports

    Page(s): 2014 - 2026
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1969 KB) |  | HTML iconHTML  

    We describe results from a channel measurement and modeling campaign for the airport surface environment in the 5-GHz band. Using a 50-MHz bandwidth test signal, thousands of power delay profiles (PDPs) were obtained and processed to develop empirical tapped-delay line statistical channel models for large airports. A log-distance path loss model was also developed. The large airport surface channel is classified into three propagation regions, and models are presented for each of the regions for two values of bandwidth. Values of the median root-mean-square (RMS) delay spread range from 500 to 1000 ns for these airports, with the 90 th percentile RMS delay spreads being approximately 1.7 ms. Corresponding correlation bandwidths (i.e., correlation value 1/2) range from approximately 1.5 MHz in non-line-of-sight (NLOS) settings to 17.5 MHz in line-of-sight (LOS) settings. Two types of statistical nonstationarity were also observed: 1) multipath component persistence and 2) propagation region transitions. We provide the multipath component probability of occurrence models and describe Markov chains that are used for modeling both phenomena. Channel tap amplitude statistics are also provided, using the flexible Weibull probability density function (pdf). This pdf was found to best fit fading tap amplitude data, particularly for frequently observed severe fading, which is characterized by fade probabilities that are worse than the commonly used Rayleigh model. Fading parameters equivalent to Nakagami-m-model values of m near 0.7 were often observed (with m = 1 being Rayleigh and m < 1 being worse than Rayleigh). We also provide channel tap amplitude correlation coefficients, which typically range from 0.1 to 0.4 but occasionally take values greater than 0.7. View full abstract»

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  • The 5-GHz Airport Surface Area Channel—Part II: Measurement and Modeling Results for Small Airports

    Page(s): 2027 - 2035
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1310 KB) |  | HTML iconHTML  

    This paper describes results from a channel measurement campaign performed at several small airports in the U.S. in the 5-GHz band. This paper is a companion to another paper, which describes channel models for large airports. We classify the small airport surface channel into three propagation regions based upon different delay dispersion conditions. The channel characteristics of these regions in the delay and frequency domains are discussed with examples. We provide empirical stochastic channel models (of different bandwidths) to accurately represent the channel on the airport surface area for all propagation regions. The models are provided in the form of tapped delay lines, and complete statistical tap descriptions are given. Several key observations, including the presence of severe amplitude fading, some correlated scattering, and statistically nonstationary behavior, are also discussed. View full abstract»

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  • Evaluation of Vehicle Penetration Loss at Wireless Communication Frequencies

    Page(s): 2036 - 2041
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB) |  | HTML iconHTML  

    Measurements and simulations of the vehicle penetration loss (VPL) at 600, 900, 1800, and 2400 MHz are presented. The measured average penetration loss varies from 3.2 to 23.8 dB, depending on frequency, illuminated vehicle side, and in-vehicle antenna orientation. VPL tends to follow a lognormal distribution. Reported penetration loss values are compared to previous measurements from the literature. View full abstract»

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  • Three-Dimensional Modeling, Simulation, and Capacity Analysis of Space–Time Correlated Mobile-to-Mobile Channels

    Page(s): 2042 - 2054
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (594 KB) |  | HTML iconHTML  

    A 3-D reference model is proposed for multiple-input multiple-output (MIMO) mobile-to-mobile (M-to-M) multipath-fading channels. From this model, a closed-form joint space-time correlation function is derived for a 3-D nonisotropic scattering environment. Two sum-of-sinusoids-based 3-D simulation models for MIMO M-to-M multipath-fading channels are proposed. The statistics of the simulation models are verified by simulation. Finally, these simulation models are used to evaluate the effect of the space-time correlation on the outage capacity of uniform linear antenna arrays and to compare the capacities of linear, circular, and spherical antenna arrays. View full abstract»

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  • Modeling and Hardware Implementation Aspects of Fading Channel Simulators

    Page(s): 2055 - 2069
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2490 KB) |  | HTML iconHTML  

    A channel simulator is an essential component in the development and accurate performance evaluation of wireless systems. Two major approaches have been widely used to produce statistically accurate fading variates, namely shaping the flat spectrum of Gaussian variates using digital filters and sum-of-sinusoids (SOS)-based methods. Efficient design and implementation techniques for these schemes are of particular importance in the design and verification of wireless systems with a relatively large number of channels, such as ad hoc networks. This paper considers the modeling and implementation aspects of fading channel simulators. First, we present a novel computationally efficient implementation of a filter-based fading channel simulator on a single field-programmable gate array (FPGA) device. The new technique significantly alleviates the challenges of real-world testing of communication systems by introducing a fast and area-efficient FPGA implementation of the fading channel. Our fixed-point implementation of a Rayleigh-fading channel simulator on an FPGA utilizes only 3% of the configurable slices, 10% of the dedicated multipliers, and 1% of the available memories on a Xilinx Virtex-II Pro XC2VP100-6 FPGA, while the simulator operates 12.5 times faster than the example sample rate. Then, we describe a compact implementation of the SOS-based fading simulator that uses only 1% of the configurable slices and 1% of the available memories on the same FPGA device while generating over 200 million complex Rayleigh-fading variates per second. View full abstract»

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  • Multistage MMSE PIC Space–Time Receiver With Non-Mutually Exclusive Grouping

    Page(s): 2070 - 2080
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (425 KB) |  | HTML iconHTML  

    The arrival of new data services for wireless mobile communications requires an efficient use of the available bandwidth. Interference-limited cellular systems based on code-division multiple access (CDMA) can benefit from multiuser detection (MUD) and beamforming with antenna array to reduce multiple-access interference. Group-based techniques have been proposed to reduce the complexity of space-time MUD and have been shown to provide a performance-complexity tradeoff between matched filtering and full MUD. In this paper, the intergroup interference, which is a limiting factor in group-based systems, is reduced using multistage parallel interference cancellation after group-based minimum mean square error (MMSE) linear filtering. In addition, the extra resources that are available at the receiver are exploited by sharing users among groups. The proposed receiver is shown to converge, as the number of stages increases, to the full space-time MMSE linear MUD filter. The results show that the new approach provides bit error rate (BER) performance close to the full MUD receiver at a fraction of the complexity. View full abstract»

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  • Switched Causal Modeling of Transmission With Clutch in Hybrid Electric Vehicles

    Page(s): 2081 - 2088
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1216 KB) |  | HTML iconHTML  

    Certain difficulties arise when attempting to model a clutch in a power train transmission due to its nonlinear behavior. Two different states have to be taken into account-the first being when the clutch is locked and the second being when the clutch is slipping. In this paper, a clutch model is developed using the energetic macroscopic representation, which is, in turn, used in the modeling of complete hybrid electric vehicles (HEVs). Two different models are used, and a specific condition defining the commutation between both models with respect to the physical energy flow is proposed. A Petri net is employed to activate one of the models, depending on the clutch state (locked or slipping). This model allows us to implement without difficulty a simulation of the clutch with a relatively short computation time. View full abstract»

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  • A Suitable Method for Ecovehicles to Control Surge Voltage Occurring at Motor Terminals Connected to PWM Inverters and to Control Induced EMI Noise

    Page(s): 2089 - 2098
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1683 KB) |  | HTML iconHTML  

    A method that is suitable for ecovehicles, which controls the surge voltage appearing at motor terminals that are connected to a pulsewidth modulation inverter with short leads that are less than the critical cable length (i.e., the shortest length at which full reflection may occur), is described here. Also, a method to control electromagnetic interference (EMI) noise, which is induced by the surge voltage, is discussed. Ecovehicles have the problem where insulation degradation of motors occurs due to the surge voltage being repeatedly applied to motor terminals during long lifecycles. EMI noise such as the shaft current and the radiated noise, which are induced by the generated surge voltage, easily diffuse into other electric devices due to the high-density packaging structure. The diffused EMI noise may cause a malfunction of the vehicle controller. An EMI noise controller is studied, which can meet the high-density packaging requirements for ecovehicles like electric vehicles. The EMI noise controller is attached on the motor terminals and simultaneously suppresses the surge voltage and the noise. After clarifying surge voltage characteristics and a circuit model for expressing the surge phenomenon through experiments and simulations, an EMI noise controller is proposed, which uses a multilayer printed power circuit technique. It is verified through simulations and experiments that the proposed controller has the ability to simultaneously control the surge voltage and the EMI noise, such as the radiated noise and the shaft current (the bearing current), which are induced by the surge voltage. View full abstract»

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  • Circularity-Based I/Q Imbalance Compensation in Wideband Direct-Conversion Receivers

    Page(s): 2099 - 2113
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (686 KB) |  | HTML iconHTML  

    Communication receivers that utilize I/Q downconversion are troubled by amplitude and phase mismatches between the analog I and Q branches. These mismatches are unavoidable in practice and reduce the obtainable image frequency attenuation to the 20-40-dB range in practical receivers. In wideband multichannel receivers, where the overall bandwidths are in the range of several megahertz and the incoming carriers located at each other's mirror frequencies have a high dynamic range, the image attenuation of the analog front-end (FE) alone is clearly insufficient. In this paper, two novel blind low-complexity I/Q imbalance compensation techniques are proposed and analyzed to digitally enhance the analog FE image attenuation in wideband direct-conversion receivers. The proposed algorithms are grounded on the concept of circular or proper complex random signals, and they are, by design, able to handle the often overlooked yet increasingly important case of frequency-dependent I/Q mismatches. The first technique is an iterative one, stemming from adaptive filtering principles, whereas the second one is a moment-estimation-based block method. The performance of the algorithms is evaluated through computer simulations, as well as real-world laboratory signal measurement examples in practical multicarrier receiver cases. Based on the obtained results, the proposed compensation techniques can provide very good compensation performance with low computational resources and are robust in the face of different imbalance levels and dynamics of the received signals, as well as many other crucial practical aspects such as the effects of the communications channel and carrier synchronization. View full abstract»

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  • Finger Replacement Schemes for RAKE Receivers in the Soft Handover Region With Multiple Base Stations

    Page(s): 2114 - 2122
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1333 KB) |  | HTML iconHTML  

    We propose and analyze new finger replacement techniques for RAKE reception in the soft handover (SHO) region with multiple base stations. The proposed schemes are basically based on the block comparison among groups of resolvable paths from different base stations and lead to the reduction of complexity while offering commensurate performance in comparison with previously proposed schemes. Relying on the newly derived analytical expressions, we investigate not only the complexity in terms of the average number of required path estimations/comparisons and the SHO overhead but the error performance of the proposed scheme over independent identically distributed (i.i.d.) fading channels as well. We also examine, via computer simulations, the effect of path unbalance/correlation as well as outdated/imperfect channel estimation and show the robustness of our proposed scheme to these practical limitations. View full abstract»

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  • Overloaded Array Processing Using Genetic Algorithms With Soft-Biased Initialization

    Page(s): 2123 - 2131
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (326 KB) |  | HTML iconHTML  

    The application of genetic algorithm (GA) techniques to the problem of overloaded arrays, in which the number of transmitted narrowband signals is greater than the number of receiver array elements, is explored. A new receiver algorithm is presented, which achieves nearly optimal performance but requires significantly less complexity than the maximum-likelihood joint detection (MLJD) receiver. It uses GA techniques with soft-biased initialization, which is efficiently generated using spatial filtering, providing dramatic convergence improvements compared with other initialization schemes. Simulations using both idealized channel models and measured channel responses are used to investigate the impact of spatial correlation and imperfect channel state information (CSI). View full abstract»

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  • An Efficient Design Methodology for Constant Power Link Adaptation Schemes in Short-Range Scenarios

    Page(s): 2132 - 2144
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (544 KB) |  | HTML iconHTML  

    The energy-efficient design of short-distance wireless communication systems requires the inclusion of circuit energy consumption in the system's total energy budget. We consider the design of constant power link adaptation schemes in which circuit energy consumption is included in the total energy budget and in which the system's instantaneous bit error rate (BER) must never exceed a predefined threshold. We show how-in numerous cases of practical importance-the dimensionality of the associated nonlinear optimization problem can be reduced from N + 1 to 1, where N denotes the number of available transmission schemes. The main contribution-a methodology that significantly simplifies the design of such constant power link adaptation schemes-is then illustrated by an example. View full abstract»

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  • Joint Adaptive Modulation and Diversity Combining With Downlink Power Control

    Page(s): 2145 - 2152
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (326 KB) |  | HTML iconHTML  

    We consider the problem of finding low-complexity, bandwidth-efficient, and processing-power-efficient transmission schemes for a downlink scenario under the framework of diversity combining. Capitalizing on recent results for joint adaptive modulation and diversity combining (AMDC) schemes, we design and analyze two AMDC schemes that utilize power control to reduce the radiated power and, thus, the potential interference to other systems/users. Based on knowledge of channel fading, the proposed schemes adaptively select the signal constellation, diversity combiner structure, and transmit power level. We show that the novel schemes also provide significant average transmit power gains compared to existing joint adaptive quadratic-amplitude modulation (QAM) and diversity schemes. In particular, over a large signal-to-noise ratio (SNR) range, the transmitted power is reduced by 30%-50%, yielding a substantial decrease in interference to coexisting systems/users, while maintaining high average spectral efficiency, low combining complexity, and compliance with bit-error-rate constraints. View full abstract»

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  • Direction-of-Arrival Estimation System for Multipath Propagation in Code-Division Multiple-Access Systems With Synthesized Virtual Planar Array Using Pilot Signals

    Page(s): 2153 - 2163
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1120 KB) |  | HTML iconHTML  

    Here, we propose a method for estimating the direction of arrival (DOA) using pilot signals in code-division multiple-access (CDMA) systems. We also report the evaluation of the performance of the proposed method by conducting simulations and experiments in an anechoic chamber and an outdoor environment. This method estimates the DOA of the arrival waves by synthesizing the data received by a virtual planar array using pilot signals. First, we describe a method for synthesizing the data received by the virtual planar array using pilot signals. Next, we present simulation results that confirmed that the accuracy of the estimation based on the virtual planar array was the same as that based on a real planar array. Last, we describe the effectiveness of the proposed system that is demonstrated through experiments in both the anechoic chamber and in an outdoor environment. View full abstract»

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  • MAI and ICI of Asynchronous Uplink MC-CDMA With Frequency Offset

    Page(s): 2164 - 2179
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (713 KB) |  | HTML iconHTML  

    In this paper, we analyze the performance of random spreading code-division multiple-access (CDMA) systems with a multicarrier in asynchronous uplink channels. We first derive the probability density function (pdf) of the multiple-access interference (MAI) plus noise and then extend the results to orthogonal frequency division multiplexing (OFDM) with intercarrier interference (ICI) that is caused by a frequency offset. We obtain the pdf of the MAI and the ICI plus noise under Rayleigh and frequency-selective fading as a function of the number of users and the spreading factor, as well as the number of subcarriers and the frequency offset. The bit-error-rate (BER) analysis shows that the power penalty from the frequency offset increases with the system loading. We develop the Gaussian approximation that provides an accurate estimation of the BER with reduced computational complexity comparing to the direct calculations using the pdf. View full abstract»

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  • Infrastructure Relay Transmission With Cooperative MIMO

    Page(s): 2180 - 2188
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (343 KB) |  | HTML iconHTML  

    An infrastructure relay system that transfers information from a base station to a randomly located mobile station (MS) using fixed-location relay stations (RSs) is studied. Transmission rates are derived for serial, parallel, and hybrid relay transmissions, considering the utilization of RSs as a means to extend the dimensionality of a multiple-input-multiple-output (MIMO) transmission. The derived transmission rate for the serial relay transmission is optimized by determining the optimal locations of the RSs and the number of hops. In addition, selection schemes for determining which RSs to activate to maximize the transmission rate are provided for parallel and hybrid relay topologies. Based on the analytic findings, numerical results are obtained for various deployment scenarios to compare and evaluate different relay topologies and design characteristics of a relay system. View full abstract»

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  • A Novel Nonlinear Joint Transmitter-Receiver Processing Algorithm for the Downlink of Multiuser MIMO Systems

    Page(s): 2189 - 2204
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (851 KB) |  | HTML iconHTML  

    This paper focuses on signal processing algorithms for the downlink of multiuser multiple-input multiple-output (MIMO) systems with multiple-antenna mobiles. A novel nonlinear joint transmitter-receiver processing algorithm is proposed based on the zero-forcing (ZF) criterion. In this algorithm, nonlinear Tomlinson-Harashima precoding (THP) is applied at the base station, whereas linear receiver processing and modulo operation are applied at each mobile. It is first shown that the proposed algorithm effectively decomposes the multiuser MIMO channel into parallel independent single-user MIMO channels, and then, the performance of each mobile can be separately optimized. Subsequently, closed-form expressions for the transmitter and receiver processing matrices are derived to optimize the asymptotic bit error rate (BER) of each mobile. When used on the downlink of multiuser MIMO systems with multiple-antenna mobiles, this algorithm achieves significantly better performance than the ZFcriterion-based nonlinear preprocessing algorithm designed for the multiuser MIMO systems with single-antenna mobiles, because it effectively utilizes the processing capabilities of the mobiles. Moreover, the proposed algorithm achieves a much higher sum capacity at a high signal-to-noise ratio (SNR) than the known block diagonalization technique due to the effective application of the nonlinear preprocessing at the transmitter. When the proposed algorithm is applied, it is found that better system performance can be achieved by suitably ordering the channel matrices of different mobiles, and a combined optimal diversity and best-first (CODBF) ordering method is proposed to perform the ordering. Simulation is used to show the advantages of the proposed algorithm and the CODBF ordering method. View full abstract»

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  • A Data Modem for GSM Voice Channel

    Page(s): 2205 - 2218
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (470 KB) |  | HTML iconHTML  

    This paper introduces a novel approach to data communication over the global system for mobile communications (GSM) voice channel. It is based on the concept of ldquosymbolsrdquo-a set of predefined signals with finite bandwidths. Data are encoded into the symbols, and the symbols are voice coded as they were speech, modulated into the GSM signal, sent over the air, GSM demodulated, voice decoded, and converted back to data. The symbols are synthesized by a genetic algorithm with the aim of maintaining separability after passing them through the voice codec. This method enables data transfer over communication networks that do not have dedicated data channels and could also be used in conjunction with other data services to balance the system load between data and voice channels, allowing optimization of system resources. We present the full algorithmic structure of the system, which performs data communications over the GSM voice channel, and we also give the results of the performance tests. View full abstract»

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  • Semi-Blind Time-Domain Equalization for MIMO-OFDM Systems

    Page(s): 2219 - 2227
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (303 KB) |  | HTML iconHTML  

    In this paper, a semi-blind time-domain equalization technique is proposed for general multiple-input-multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) systems. The received OFDM symbols are shifted by more than or equal to the cyclic prefix (CP) length, and a blind equalizer is designed to completely suppress both intercarrier interference (ICI) and intersymbol interference (ISI) using second-order statistics of the shifted received OFDM symbols. Only a one-tap equalizer is needed to detect the time-domain signals from the blind equalizer output, and one pilot OFDM symbol is utilized to estimate the required channel state information for the design of the one-tap equalizer. The technique is applicable irrespective of whether the CP length is longer than, equal to, or shorter than the channel length. Computer simulations show that the proposed technique outperforms the existing techniques, and it is robust against the number of shifts in excess of the CP length. View full abstract»

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  • Spatial Modulation

    Page(s): 2228 - 2241
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2009 KB) |  | HTML iconHTML  

    Spatial modulation (SM) is a recently developed transmission technique that uses multiple antennas. The basic idea is to map a block of information bits to two information carrying units: 1) a symbol that was chosen from a constellation diagram and 2) a unique transmit antenna number that was chosen from a set of transmit antennas. The use of the transmit antenna number as an information-bearing unit increases the overall spectral efficiency by the base-two logarithm of the number of transmit antennas. At the receiver, a maximum receive ratio combining algorithm is used to retrieve the transmitted block of information bits. Here, we apply SM to orthogonal frequency division multiplexing (OFDM) transmission. We develop an analytical approach for symbol error ratio (SER) analysis of the SM algorithm in independent identically distributed (i.i.d.) Rayleigh channels. The analytical and simulation results closely match. The performance and the receiver complexity of the SM-OFDM technique are compared to those of the vertical Bell Labs layered space-time (V-BLAST-OFDM) and Alamouti-OFDM algorithms. V-BLAST uses minimum mean square error (MMSE) detection with ordered successive interference cancellation. The combined effect of spatial correlation, mutual antenna coupling, and Rician fading on both coded and uncoded systems are presented. It is shown that, for the same spectral efficiency, SM results in a reduction of around 90% in receiver complexity as compared to V-BLAST and nearly the same receiver complexity as Alamouti. In addition, we show that SM achieves better performance in all studied channel conditions, as compared with other techniques. It is also shown to efficiently work for any configuration of transmit and receive antennas, even for the case of fewer receive antennas than transmit antennas. View full abstract»

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  • A Train-Once Approach for Location Estimation Using the Directional Propagation Model

    Page(s): 2242 - 2256
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1633 KB) |  | HTML iconHTML  

    Location estimation that is based on the mobile phone network has drawn considerable attention in the field of wireless communications. Among the different mobile location estimation methods, the one that estimates a mobile station location with reference to a wave propagation model is shown to be effective and is applicable to different kinds of cellular networks, including Global System for Mobile Communications (GSM), cdmaOne, CDMA2000, and the Universal Mobile Telecommunications System. We have designed a train-once approach for location estimations using the directional propagation model (DPM). The DPM is an improved model that is based on the traditional free-space wave propagation model with the directional gain and environmental factors integrated in the estimation. The train-once approach works because we observe that different types of antennas are designed for different types of environments. Thus, a parameter estimation is related to the antenna type and, in turn, related to the environment. In this paper, we report our study of the train-once approach with the DPM for location estimations. We have tested our model with 192 177 sets of real-life data that have been collected from a major mobile phone operator in Hong Kong. Experimental results show that the train-once approach with the DPM is practical and outperforms the existing location estimation algorithms in terms of accuracy, stability among different types of terrains, and success rates. View full abstract»

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  • Average BER Analysis for M -ary FSK Signals in Nakagami- q (Hoyt) Fading With Noncoherent Diversity Combining

    Page(s): 2257 - 2267
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (413 KB) |  | HTML iconHTML  

    This paper analyzes the average bit error rate (BER) of noncoherent M-ary frequency-shift keying (FSK) signals over multichannel nonidentically distributed Nakagami-q (Hoyt) fading employing diversity combining. The first part of the paper considers the conventional postdetection noncoherent equal-gain combiner (NC-EGC), in which a Fourier series inversion formula is employed to derive a simple and rapidly converging series-based expression for the system average BER. This expression is valid for arbitrary values of received average signal-to-noise ratios (SNRs) and fading parameters. The derived expression is then compared with some existing ones in the literature, and the results show a large reduction in computational complexity, particularly when M and/or the diversity order increases. In the second part, a new noncoherent combiner is proposed to achieve improvements over the conventional NC-EGC. It is also shown that this new combiner results in a simple closed-form expression for the system average BER that is given in terms of elementary functions; hence, it can be easily numerically evaluated with noticeable computation efficiency. 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