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Vehicular Technology, IEEE Transactions on

Issue 4 • Date Nov 1995

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Displaying Results 1 - 9 of 9
  • A digital coherent receiver suitable for land-mobile satellite communications

    Publication Year: 1995 , Page(s): 771 - 778
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (848 KB)  

    Describes an advanced coherent demodulation technique suitable for land-mobile satellite communications. The proposed technique features a combined narrow/wide band dual open loop (DOL) carrier phase estimator, which effectively enables the coherent receiver to track fast phase fluctuations caused by fading, without degradation in phase slip characteristics. Additionally, an open loop phase estimator has inherent quick recovery performance. Its bit error rate (BER) performance is shown to be superior to that for existing detection schemes, achieving a 10-2 BER at 6.3 dB Eb/N0 (0.9 dB greater than the theoretical Eb/N0 condition for perfect carrier phase tracking) for QPSK over a Rician fading channel with the 10 dB Rician factor and the 1/16 baud rate fading pitch. The paper also describes a quick bit timing recovery scheme, with interpolation, featuring an open loop structure. Further, it presents an experimental digital modem developed through the use of digital signal processors View full abstract»

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  • A single-layer slotted leaky waveguide array antenna for mobile reception of direct broadcast from satellite

    Publication Year: 1995 , Page(s): 749 - 755
    Cited by:  Papers (32)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (680 KB)  

    This paper proposes a single-layer slotted leaky waveguide array antenna for mobile DBS reception. A single-layer feed structure is proposed, where the feed waveguide is in the same layer as the radiating waveguides. This results in the simple fabrication of slotted waveguide arrays, suitable for mass production. Short radiating leaky waveguides are used to get a large beam-tilting angle of about 50° for the horizontal installation of the antenna and a beamwidth broad enough to dispense with mechanical steering in the elevation plane. A prototype antenna sized 30 cm by 21 cm has a maximum of 74% efficiency and more than 69% efficiency within the DBS band. It also has a broad l-dB beamwidth of 7.5° in the elevation plane, which enables clear DBS reception by a picture tube display over about one-third the area of Japan without elevation tracking View full abstract»

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  • Diagnosis of multiple sensor and actuator failures in automotive engines

    Publication Year: 1995 , Page(s): 779 - 789
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (836 KB)  

    Unlike cases where only a single failure occurs, fault detection and isolation of multiple sensor and actuator failures for engines are difficult to achieve because of the interactive effects of the failed components. If faults all appear either in sensors only or in actuators only, many existing residual generators which provide decoupled residual signals can be employed directly to obtain proper fault detection and isolation. However, when both sensor and actuator failures occur at the same time, their mutual effects on residuals make fault isolation particularly difficult. Under such circumstances, further decision logic is required. In the paper, the authors propose a hexadecimal decision table to relate all possible failure patterns to the residual code. The residual code is obtained through simple threshold testing of the residuals, which are the output of a general scheme of residual generators. The proposed diagnostic system incorporating the hexadecimal decision table has been successfully applied to automotive engine sensors and actuators in both simulation and experimental analyses. Enhancement of the present diagnostic performance by implementing an additional sensor is also described View full abstract»

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  • Calculating the mean and variance of power sums with two log-normal components

    Publication Year: 1995 , Page(s): 756 - 762
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    An efficient method for accurately calculating the mean and variance of power sums with two log-normal components is presented. It involves numerical quadrature with integrands consisting of Gaussian probability density functions. Only the technique of transformation and the trapezoidal rule are used in the evaluation. The whole computational work and roundoff error are much lower than the one by Schwartz and Yeh (1982). Because of its high efficiency, no least-squares fit is necessary View full abstract»

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  • Optical recognition of motor vehicle license plates

    Publication Year: 1995 , Page(s): 790 - 799
    Cited by:  Papers (64)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (992 KB)  

    A system for the recognition of car license plates is presented. The aim of the system is to read automatically the Italian license number of a car passing through a tollgate. A CCTV camera and a frame grabber card are used to acquire a rear-view image of the vehicle. The recognition process consists of three main phases. First, a segmentation phase locates the license plate within the image. Then, a procedure based upon feature projection estimates some image parameters needed to normalize the license plate characters. Finally, the character recognizer extracts some feature points and uses template matching operators to get a robust solution under multiple acquisition conditions. A test has been done on more than three thousand real images acquired under different weather and illumination conditions, thus obtaining a recognition rate close to 91% View full abstract»

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  • Channel coding strategies for cellular radio

    Publication Year: 1995 , Page(s): 763 - 770
    Cited by:  Papers (17)  |  Patents (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (788 KB)  

    To improve re-use of time/frequency slots in a cellular radio system, it is desirable for the average interference levels seen by all users to be made approximately equal. The authors provide constructions based on orthogonal latin squares that guarantee different sets of users will interfere in successive slots. When signal to interference ratios are independent from successive symbols, channel codes can provide a large diversity gain which is far in excess of the gain against additive noise. Consequently, coding with interleaving fits together very naturally with this construction. The authors illustrate how to achieve large performance improvement using convolutional codes with low decoding delay in a slow hopped system View full abstract»

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  • An intelligent multimode voice communications system for indoor communications

    Publication Year: 1995 , Page(s): 735 - 748
    Cited by:  Papers (7)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1240 KB)  

    A novel high-quality, low-complexity dual-rate 4.7 and 6.5 kbits/s algebraic code excited linear predictive codec is proposed for adaptive multi-mode speech communicators, which can drop their source rate and speech quality under network control in order to invoke a more error resilient modem amongst less favorable channel conditions. Source-matched binary Bose-Chaudhuri-Hocquenghem (BCH) codecs combined with unequal protection diversity- and pilot-assisted 16and 64-level quadrature amplitude modulation (16-QAM, 64-QAM) are employed in order to accommodate both the 4.7 and the 6.5 kbits/s coded speech bits at a signaling rate of 3.1 kBd. Assuming an excess bandwidth of 100%, in a bandwidth of 200 kHz 32 time slots can be created, which allows us to support in excess of 50 users, when employing packet reservation multiple access (PRMA). Good communications quality speech is delivered in an equivalent bandwidth of 4 kHz, if the channel signal-to-noise ratio (SNR) and signal-to-interference ratio (SIR) of the benign indoors cordless channel are in excess of about 15 and 25 dB for the lower and higher speech quality 16-QAM and 64-QAM systems, respectively, and the PRMA time-slots are sufficiently uninterfered due to using time-slot classification algorithms and due to the attenuation of partitioning walls and ceilings View full abstract»

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  • Improved post-detection processing for limiter-discriminator detection of CPM in a Rayleigh, fast fading channel

    Publication Year: 1995 , Page(s): 729 - 734
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (408 KB)  

    A simple, robust processing strategy, called the fading magnitude-integrate sample and dump (FM-ISD) processor, is proposed for use with limiter-discriminator detection of CPM signals in Rayleigh, fast fading channels. The FM-ISD processor is introduced as a simplification of an optimal estimator-correlator receiver. The performance is compared to a standard integrator processor and found to provide an improvement in performance for all values of signal-to-noise ratio. The FM-ISD processor is also shown to be robust to changes in modulation format, channel fading rate and pre-detection filter type View full abstract»

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  • Performance of the noncoherent biquadratic and GLRT receivers over two-path channels with known amplitudes and Rayleigh fading

    Publication Year: 1995 , Page(s): 715 - 728
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1000 KB)  

    Noncoherent detection over Rayleigh fading diversity channels with known or perfectly estimated amplitudes is studied for binary, uniformly orthogonal signaling. The optimum receiver is well known, but is too difficult to implement. Hence, two suboptimal receivers are considered: the “biquadratic” receiver, optimum at low signal-to-noise ratios (SNR's), and the “bilinear” receiver (optimum at high SNR's) which is also a generalized likelihood ratio test (GLRT) receiver for this case. We analyze the performances of the two suboptimal receivers over two-path channels and compare them to the basic quadratic receiver. For this purpose we present a general method for computing the error probability that can be applied to any dual-diversity binary detection problem whenever the method of characteristic functions fails. We present the exact analytical expressions for the biquadratic receiver, and the numerically computed results for the GLRT receiver, in terms of the conditional, average and asymptotic error probabilities. It is shown that the two receivers are rather close in performance in most of the SNR ranges of interest 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.

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Meet Our Editors

Editor-in-Chief
Yuguang Michael Fang
University of Florida