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Vehicular Technology, IEEE Transactions on

Issue 1 • Date Feb 1990

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Displaying Results 1 - 10 of 10
  • High-reliability data transfer over the land mobile radio channel using interleaved hybrid-ARQ error control

    Publication Year: 1990 , Page(s): 48 - 55
    Cited by:  Papers (27)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (584 KB)  

    Several coding techniques are combined to create a simple error control system capable of providing very low end-to-end symbol error rates over a digital mobile phone link. Interleaving is used to spread out the impact of deep fades, allowing for the use of shorter block codes with correspondingly simple encoders and decoders. The degree of error control provided by these block codes is then substantially improved through the adoption of a type-1 hybrid-ARQ protocol. The performance of this system is explored in detail for implementation based on Reed-Solomon codes View full abstract»

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  • The performance enhancement of multibeam adaptive base-station antennas for cellular land mobile radio systems

    Publication Year: 1990 , Page(s): 56 - 67
    Cited by:  Papers (213)  |  Patents (50)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1040 KB)  

    The problem of meeting the proliferating demands for mobile telephony within the confinement of the limited radio spectrum allocated to these services is addressed. A multiple-beam adaptive base-station antenna is proposed as a major system component in an attempt to solve this problem. The approach is demonstrated by employing an antenna array capable of resolving the angular distribution of the mobile users as seen at the base-station site, and then using this information to direct beams toward either lone mobiles, or groupings of mobiles, for both transmit and receive modes of operation. The energy associated with each mobile is thus confined within the addressed volume, greatly reducing the amount of cochannel interference experienced from and by neighboring cochannel cells. To ascertain the benefits of such an antenna, the conventional and proposed antenna systems are modeled in a typical mobile radio environment. For a given performance criterion, the theoretical results indicate that a significant increase in the spectral efficiency, or capacity, of the network is obtainable with the proposed antenna View full abstract»

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  • Decoding performance of linear block codes using a trellis in digital mobile radio

    Publication Year: 1990 , Page(s): 68 - 74
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (532 KB)  

    Trellis decoding of linear block codes in a Rayleigh fading channel is discussed. Two methods for calculating metric values for each bit in a received block are considered: the values are calculated from the received signal envelope sample and from the demodulator output. Bit error rate (BER) performances of hard decision and trellis decoding are compared using Hamming (7, 4) and Golay (24, 12) codes in computer simulations and laboratory experiments. A simplified trellis decoding algorithm, in which the hard decision output of a bit with an envelope sample greater than the threshold value is accepted as correct, is presented. Laboratory experimental results for trellis decoding in combination with Gaussian minimum-shift-keying (GMSK) modulation and frequency detection are shown. The effect of n-bit A/D-conversion in signal envelope sampling is investigated experimentally. The results show that the trellis decoding algorithm improves BER performance View full abstract»

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  • Electromagnetic levitation system by means of salient-pole type magnets coupled with laminated slotless rails

    Publication Year: 1990 , Page(s): 83 - 87
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (316 KB)  

    An electromagnetic levitation (EML) system that has bogie-trucks magnetically levitated along laminated rails and driving linear induction motors of short stator type onboard is discussed. The levitation magnets are salient-pole type with laminated iron cores. The salient-pole-type magnet is lighter and has much smaller coil impedance that the U-shaped magnet. Results for trial designs of the EML bogie-trucks are given, and it is shown that the control performance of the new system is much better than that of the EML system which uses U-shaped magnets and unlaminated iron paths for magnets and rails View full abstract»

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  • A novel demodulator/detector for digital and analog signals on LMR channels

    Publication Year: 1990 , Page(s): 6 - 16
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (868 KB)  

    The design, implementation, and performance of an all-digital demodulator/detector suitable for differential phase-shift keying (DPSK), continuous-phase frequency-shift keying (CPFSK), frequency-shift keying (FSK), and analog FM are discussed. In this modulator/detector, two detectors, one noncoherent and another differentially coherent, operate simultaneously to provide data detection and automatic frequency control (AFC). Test results indicate that the system provides improved performance over the conventional analog quadrature detector for two-period raised-cosine (2RC) CPFSK modulation in additive white Gaussian noise (AWGN) and Rayleigh fading channels. Being all-digital, the demodulator/detector is well suited for integrated circuit implementation. In addition, the system performs as well as the analog quadrature detector for analog FM voice transmissions, thereby maintaining full compatibility with analog land mobile radio (LMR) transmissions View full abstract»

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  • An integrated voice/data system for mobile indoor radio networks

    Publication Year: 1990 , Page(s): 75 - 82
    Cited by:  Papers (29)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (608 KB)  

    A centralized, integrated voice/data radio network for fading multipath indoor radio channels is proposed and analyzed. The packets of voice and data are integrated through a movable boundary method. The uplink channel access uses a framed-polling protocol whereas the downlink uses a time-division multiple-access (TDMA) scheme. This system dynamically switches between two transmission rates and uses multiple antennas to maximize the throughput in the fading multipath indoor environment. Throughput and delay characteristics of the system are analyzed using four different techniques. The results are compared with those of Monte Carlo computer simulations. A simple relationship between the number of voice terminals and the throughput of the data traffic are derived for an upper bound of 10-ms delay for the data packets View full abstract»

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  • Code division multiple access versus frequency division multiple access channel capacity in mobile satellite communication

    Publication Year: 1990 , Page(s): 17 - 26
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (716 KB)  

    A comparison between frequency-division multiple access (FDMA) and code-division multiple access (CDMA) when both methods operate in the mobile satellite communication environment is presented. The mobile satellites under consideration use multiple beams or scan beam antennas and employ frequency reuse of the allocated L-band frequency spectrum. Because CDMA can better absorb Doppler and multipath effects and permits higher rate coding, it appears in general, with practical considerations set aside, to be the more capable system View full abstract»

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  • Convolutionally interleaved PSK and DPSK trellis codes for shadowed, fast fading mobile satellite communication channels

    Publication Year: 1990 , Page(s): 37 - 47
    Cited by:  Papers (28)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (784 KB)  

    Using a model from the literature, the performance of convolutionally interleaved phase-shift-keying (PSK) and differential phase-shift-keying (DPSK) trellis codes for digital speech transmission over shadowed mobile satellite communication channels is determined by computer simulation. First the characteristics of fading channels are examined and analyzed in terms of the probability distributions of amplitude, phase, and burst errors. A statistical method, using a histogram approach, is utilized along with the simulations of fading channels to generate these probability distributions. A test for channel burst error behavior is presented. A periodic convolutional interleaver/deinterleaver to be used with trellis coding to combat slow fading in digital, shadowed mobile satellite channels is designed. This interleaver ha less than half the time delay for the same bit error performance than a block interleaver. The results show that the periodic convolutional interleaver provides considerable improvement in the error and time delay performance of mobile satellite communication channels for up to average shadowing conditions as compared to other techniques View full abstract»

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  • Intersymbol interference reduction for differential MSK by nonredundant error correction

    Publication Year: 1990 , Page(s): 27 - 36
    Cited by:  Papers (3)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (628 KB)  

    A theoretical analysis and experimental results for differential detection of minimum-shift keying (MSK) with nonredundant error correction are described. The proposed demodulator utilizes the output detected from the difference in phase over two or three time slot intervals along with the conventional detector output. A single error can be corrected by using two differential detectors, and a single and a double error can be corrected by using three detectors. It is shown that the error rate performance is improved, especially in the presence of intersymbol interference (ISI), without the addition to the transmitted data of redundant bits. Simulation and experimental results agree with the theoretical analysis, which shows that the degradation of differential detection relative to coherent detection is reduced from 2.2 dB without error correction to 1.2 dB with single error correction and to 0.7 dB with double error correction. The method can be applied effectively to mobile communications over a fading channel or to time-division multiple-access (TDMA) communications using burst mode transmission View full abstract»

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  • An experimental study on the intensity of scattering wave by automobile body as multipath source in mobile communications

    Publication Year: 1990 , Page(s): 2 - 5
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (308 KB)  

    The measurement of the electromagnetic wave scattering pattern of a reduced automobile model by means of a microwave simulation experiment in an electromagnetic anechoic chamber is discussed. The results show that the maximum level of the automobile's scattering pattern reaches -10 to -22 dB compared with the incident wave intensity. This indicates that when a mobile station is in a heavy-traffic city zone, the scattering from vehicles in the vicinity of the station must be taken into account as a source of multipath 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