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Vehicular Technology, IEEE Transactions on

Issue 2 • Date May 1993

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Displaying Results 1 - 12 of 12
  • Performance of narrowband CPM systems with limiter-discriminator-integrator detection and decision feedback equalization in mobile radio channels

    Publication Year: 1993 , Page(s): 166 - 176
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (756 KB)  

    A completely analytical approach is presented to achieve error probability analysis of limiter-discriminator-integrator (LDI) detection of binary continuous-phase modulation in a land mobile radio channel characterized by Rayleigh fading and Doppler effects. Optimum choice of the postdetection integration time is carried out when varying both system parameters and propagation characteristics, namely the Doppler shift. The improvements obtainable by means of decision feedback equalization (DFE) are also considered, in the presence of error propagation. The algorithm allows a very general analysis, which can be applied both to a partial and a full response modulation pulse, with narrowband IF filter and multipath propagation. This leads to the optimization of various system parameters, such as filter bandwidth, the modulation index, and the postdetection integration time, whatever the choice of the modulation pulse View full abstract»

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  • Multiple differential detection of continuous phase modulation signals

    Publication Year: 1993 , Page(s): 186 - 196
    Cited by:  Papers (9)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (840 KB)  

    A sequence estimation algorithm for the differential detection of the continuous phase modulation (CPM) signals, yielding significant gains in BER performance and with considerable resistivity to fading, is introduced. These advantages, along with the reduced hardware complexity, low cost, and fast synchronization which characterize the differential detector, make the proposed receiver useful for land mobile radio and mobile-satellite communications. The new receiver is based on multiple differential detection. The multiple differential detection strategy provides the decoder with more information regarding the transmitted data and applies a noise decorrelation process on the received signal, useful to the sequence estimation. The algorithm is derived in a general form, and can be applied on any CPM scheme, with any degree of complexity. The authors have evaluated the receiver for two of the most popular CPM schemes, the tamed frequency modulation (TFM) and Gaussian minimum-shift keying (GMSK) (with B1 T=0.25), in the presence of additive white Gaussian noise (AWGN) and Rician fading. The BER performance evaluation results indicated significant gains and considerable reduction of error floors. In AWGN improvements close to 9 dB have been verified View full abstract»

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  • Mobile radio group communications by satellite

    Publication Year: 1993 , Page(s): 121 - 130
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (948 KB)  

    Mobile radio group communications enable a closed group of users to communicate among themselves using push-to-talk (PTT), half duplex transmissions, such that one's transmission is received by all. New protocol designs are presented which support group communications over mobile satellite systems. A new demand assignment multiple access (DAMA) protocol is necessitated by the inappropriateness of call-based channel assignments. Channels are assigned to individual user-groups engaged in active conversations. As members of a user-group contend for access to the assigned channel, access control by the usual manual methods is ineffective due to the very long round trip delay. A novel signaling protocol which automates access control is proposed. Carrier sensing, signal capture, and collision detection are employed to minimize access contentions. The throughput and holding time of the assigned channel are analyzed. Numerical results show that the access control protocol improves the capacity of the assigned channel by up to 65% View full abstract»

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  • FH-MFSK multiple-access communications systems performance in the factory environment

    Publication Year: 1993 , Page(s): 148 - 155
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (668 KB)  

    A frequency-hopped (FH), M-ary frequency-shift-keyed (MFSK), spread-spectrum (SS) communication system operating over the factory radio channel is described. The performance of the system for Rayleigh, Rician, and log-normal multipath fading for factory environments is investigated. The statistics of these channels, based on recent channel modeling studies, are used to evaluate the performance of the FH-MFSK system. A quadrature rule is employed to calculate the channel error probabilities. The average bit error rate (BER) is formulated and is evaluated approximately using Stirling's formula. The numbers of simultaneous users in terms of the number of hopped frequencies, number of MFSK chips, receiver threshold, signal-to-noise ratio, and channel statistics at a fixed BER for Rayleigh, Rician, and lognormal fading channels are determined View full abstract»

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  • Analysis and measurement of FM click rate in slow Rician fading

    Publication Year: 1993 , Page(s): 197 - 204
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (556 KB)  

    A closed-form expression is derived for the average click rate in an FM system when the transmitted signal experiences Rician fading. Click rate is useful for predicting the bit-error-rate (BER) performance of a digital frequency modulation (FM) signal demodulated by a limiter-discriminator. In the derivations, the assumption is made that the fading is relatively constant over a baud interval (the slow fading case). Also, a definition of the signal-to-noise ratio is used that includes the multipath as a signal component rather than treating it as noise. The validity of the formulae for positive and negative click rates has been verified by experiment View full abstract»

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  • A dual-tone reference digital demodulator for mobile digital communication

    Publication Year: 1993 , Page(s): 156 - 165
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (724 KB)  

    A demodulator applicable to the dual-pilot tone modulation technique is presented. Examination of orthogonal and ISI (intersymbol interference) free pulse shapes leads to the novel demodulator structure. This demodulator is advantageous because the processing is strictly linear, the pilot channel and data channel ideally do not interfere or create self-noise, no differential encoding is required since no phase ambiguity is created with the pilot tone processing, and near ideal bit error probability performance is achieved. This demodulator offers an alternative to the transmitted tone-in-band and the pilot symbol assisted modulation techniques. The author considers π/4-QPSK modulation with 33% excess bandwidth in the isotropic time-varying fading channel as a design example View full abstract»

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  • The areawide real-time traffic control (ARTC) system: a new traffic control concept

    Publication Year: 1993 , Page(s): 212 - 224
    Cited by:  Papers (7)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1160 KB)  

    A traffic control system, called areawide real-time traffic control (ARTC), that addresses frequent occurrences of congestion and provides areawide traffic progression is presented. The signal controllers in ARTC are interconnected through a computer network. By exchanging traffic flow information among the signal controllers, ARTC provides a new concept in areawide traffic control. With a global view of the traffic in the area, ARTC anticipates congestion. Simulation results of the ARTC prototype control algorithm over a linear road topology are also presented, and the results show significant improvement over an optimized fixed time control. The signal controllers and the computer network are designed to support the real-time communication requirements and a sufficient level of fault tolerance View full abstract»

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  • Spread-spectrum path diversity in a shadowed Rician fading land-mobile satellite channel

    Publication Year: 1993 , Page(s): 131 - 136
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (428 KB)  

    The effects of two types of path diversity techniques, namely selection diversity and maximal ratio combining, on the bit error probability are investigated for direct-sequence spread-spectrum (DS/SS) transmission in a land mobile satellite channel using coherent binary phase-shift keying (BPSK) modulation. It is assumed that the channel consists of a log-normally shadowed line-of-sight signal plus Rayleigh distributed multipath signals. The bit error probability is evaluated for light, average, and heavy shadowing. The performance is also measured in terms of the outage probability View full abstract»

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  • In-room transmission BER performance of anti-multipath modulation PSK-VP

    Publication Year: 1993 , Page(s): 177 - 185
    Cited by:  Papers (7)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (728 KB)  

    The BER (bit error rate) performance of an anti-multipath modulation π/4-QPSK-VP is evaluated in comparison to a conventional differential π/4-QPSK, when applied to high-speed digital radio transmission within a room where both transmitting and receiving antennas are set up, using a transmission experiment and a BER calculation. Through this transmission experiment at about 3 and 6 Mb/s, π/4-QPSK-VP was confirmed to improve the BER significantly for both data rates in two test rooms. A delay profile measurement was additionally carried out to characterize the propagation channels of the test rooms and to find out an appropriate channel model. The BER calculation based on the above channel model, which was confirmed to estimate the upper bound of a floor error rate sufficiently in comparison to the transmission experiment, reveals the relationship between the data rate and the BER and indicates an optimum and a maximum data rate for π/4-QPSK-VP with respect to the maximum delay spread of the room. The results show that π/4-QPSK-VP is estimated to raise the available data rate up to about 20 times over that of π/4-QPSK for a BER of 10-4, although π/4-APSK-VP requires twice the transmission bandwidth View full abstract»

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  • Rayleigh fading compensation for QAM in land mobile radio communications

    Publication Year: 1993 , Page(s): 137 - 147
    Cited by:  Papers (128)  |  Patents (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (768 KB)  

    A pilot symbol-aided Rayleigh fading compensation is investigated for M-ary quadrature amplitude modulation (QAM) to achieve highly spectrally efficient land mobile communication systems. The optimum parameters for fading compensation, bit error rate (BER) performance against Eb/N0 (energy per bit to the noise power spectrum density), adjacent channel interference, and cochannel interference for 16-QAM, 64-QAM, and 256-QAM, and the spectral efficiencies for these modulation schemes in Rayleigh fading environments are investigated by computer simulation. To further verify the effect of pilot symbol-aided fading compensation from a a practical point of view, a 16-QAM modem is implemented, laboratory experiments are executed, and the impact of the dynamic range limitation due to the resolution of the analog-to-digital (A/D) converters is evaluated, along with the imperfection of the analog circuits. It is demonstrated by computer simulation and laboratory experiments that the pilot symbol-aided fading compensation can sufficiently compensate for fast varying Rayleigh fading, and 16-QAM gives the highest spectral efficiency in the case of cellular systems View full abstract»

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  • Optimal frame pattern design for a TDMA mobile communication system using a simulated annealing algorithm

    Publication Year: 1993 , Page(s): 205 - 211
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (616 KB)  

    Different relative positions of voice and data slots within the frame of a TDMA (time-division multiple access) mobile communication system may result in different system data throughput. The design of the optimal relative position, namely the frame pattern which can achieve maximum data throughput, is described. This design method can be formulated as solving a combinatorial optimization problem. Generally, the global optimal solution of such a problem is hard to find using conventional methods, which may be computationally intractable. A reliable and effective method called a simulated annealing algorithm is applied to obtaining the global optimum. Numerical results reveal that there exist various optimal frame patterns for different ranges of traffic load and the optimal frame pattern can achieve great throughput improvement over a random frame pattern View full abstract»

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  • Rail track distributed transmission line impedance and admittance: theoretical modeling and experimental results

    Publication Year: 1993 , Page(s): 225 - 241
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1288 KB)  

    Frequency-dependent distributed transmission line self and mutual impedances and admittances for a single-track, power-rail electrified railway are obtained by experiment and modeling. Impedance results obtained by numerical calculation from an electromagnetic minimum energy field solution using the finite-element method are compared with analytic impedance models based on the Carson-Pollaczek equations for a stratified, weakly conducting ground and with practical experimental measurements made on a short length of rail track. The running rail self conductances and the power rail to running rail mutual capacitances are also evaluated by the finite-element method and compared with experimental measurements. A physical interpretation of the results is given in terms of conductive and induced ground currents caused by finite ground conductivity and relative permittivity 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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Editor-in-Chief
Yuguang Michael Fang
University of Florida