Showing papers on "Fading distribution published in 1976"
TL;DR: The performance of short constraint length convolutional codes in conjunction with binary phase-shift keyed (BPSK) modulation and Viterbi maximum likelihood decoding on the classical Rician fading channel is examined in detail and fairly general upper bounds on bit error probability performance in the presence of fading are obtained.
Abstract: The performance of short constraint length convolutional codes in conjunction with binary phase-shift keyed (BPSK) modulation and Viterbi maximum likelihood decoding on the classical Rician fading channel is examined in detail. Primary interest is in the bit error probability performance as a function of E_{b}/N_{0} parameterized by the fading channel parameters. Fairly general upper bounds on bit error probability performance in the presence of fading are obtained and compared with simulation results in the two extremes of zero channel memory and infinite channel memory. The efficacy of simple block interleaving in combating the memory of the channel is thoroughly explored. Results include the effects of fading on tracking loop performance and the subsequent impact on overall coded system performance. The approach is analytical where possible; otherwise resort is made to digital computer simulation.
97 citations
TL;DR: An approach is presented for the analysis of phase-locked loops whose input signal has passed through time-varying channels, which includes the Rice-Nakagami, Rayleigh, and lognormal fading channels.
Abstract: An approach is presented for the analysis of phase-locked loops whose input signal has passed through time-varying channels. The specific channels considered in detail are the Rice-Nakagami, Rayleigh, and lognormal fading channels. Loop performance is characterized in terms of the steady-state probability density function of the reduced phase error process. The basic parameters which characterize performance include the loop signal-to-noise ratio (SNR) and the variance and bandwidth of the fading components introduced by the channel. Particular channel models are used to illustrate the theory for the firstorder loop. The results are also applied to the analysis of the PSK noisy reference problem in the presence of these time-varying channels.
56 citations
TL;DR: In this paper, the authors proposed a root square sum approximation technique to determine the allottment of a small zone high capacity system in the UHF band, where various performance degradation causes, such as signal fading, cochannel interference, intermodulation disturbance, and sensitivity suppression, were considered.
Abstract: For designing a land mobile radio system, particularly a small zone high capacity system in the UHF band, various performance degradation causes, such as signal fading, cochannel interference, intermodulation disturbance, and sensitivity suppression, should be inclusively taken into account. The magnitudes of these degradations vary with time, because of field strength variation due to multipath fading, environmental shadowing effect, and the distance of mobile station from the base. Hence the circuit performance objective given in a probablistic form must be allotted for in each one of these causes. Variabilities of these degradations are estimated in terms of desired and undesired signal field strength variations. In the estimation, path diversity effect is considered and a root square sum approximation technique is employed. Also, the process used to determine the allottment is proposed from the viewpoints of efficient frequency utilization and realizability of base and mobile radio equipment.
13 citations
TL;DR: A new method of producing a discrete-level approximation to a Rayleigh fade by means of a quasi-random digital process that offers considerable advantages over existing methods in cost, simplicity and flexibility, having an exactly repeatable fading pattern and a fading rate which may be easily changed by varying the digital clock rate.
Abstract: The paper describes a new method of producing a discrete-level approximation to a Rayleigh fade by means of a quasi-random digital process. This offers considerable advantages over existing methods in cost, simplicity and flexibility, having an exactly repeatable fading pattern and a fading rate which may be easily changed by varying the digital clock rate. Mathematical analysis and experimental evidence show that the output closely approximates to a Rayleigh fade in all respects. A description is given of a prototype h.f. ionospheric channel simulator incorporating the design. In addition to Riceian fading the prototype allows the simulation of two-path propagation, Doppler shift, and additive Gaussian noise. Some practical applications of the simulator are discussed.
10 citations
TL;DR: This concise paper summarizes the results of the first study of the effect of finite buffers on a variable-rate system for fading channels, focusing on the critical topic of buffer size.
Abstract: Transmission of data with receiver-controlled bit rate is an effective way to reduce the effect of signal-to-noise ratio (SNR) fluctuations, as in a fading channel. All previous publications on this subject ignore the critical topic of buffer size. This concise paper summarizes the results of the first study of the effect of finite buffers on a variable-rate system for fading channels.
9 citations
TL;DR: Approximate solutions for symmetric and asymmetric correlation functions have been obtained and the results plotted for typical ionospheric parameters.
Abstract: Signals in a satellite-earth communication link pass through the ionosphere where there may exist random irregularities. These random irregularities will scatter and distort the Signal, producing a fading channel. Such a channel is generally characterized by the symmetric and asymmetric correlation functions. Approximate solutions for these functions have been obtained and the results plotted for typical ionospheric parameters. Some of the results are shown in terms of coherence bandwidth.
4 citations
TL;DR: The effect of such a finite buffer on system performance is derived and these theoretical results are validated using computer simulation.
Abstract: Intermittent data transmission, that is, sending data only when the signal strength is above a desired threshold, has been shown to be extremely effective at combatting the effects of signal fading. However, such a system must usually interface with a uniform data source and sink by the use of finite buffers. When the buffer fills, transmission must occur during bad signal conditions and when it empties, no transmission can occur. The effect of such a finite buffer on system performance is derived and these theoretical results are validated using computer simulation. Finally, adaptive methods to improve performance are investigated and two areas of application of an intermittent System are examined.
4 citations
TL;DR: In this paper, an analysis of the energy signal degradation of an M-ary p.k.s. system due to intersymbol interference and fading is carried out in the presence of nonselective fading in the channel.
Abstract: The results of an investigation of the evaluation of energy signal degradation of an M-ary p.s.k. system due to intersymbol interference and fading are analysed. Attention is concentrated upon the influence of intersymbol interference caused by the limited band of the receiver filter as well as the transmitter one. As far as the channel is concerned, it has been assumed there is nonselective fading in it. Part 1 presents the analysis method being applied; Part 2 analyses the energy degradation characteristics of M-ary signals resulting from intersymbol interference in the case when no fading occurs in the channel; Part 3 analyses the influence of intersymbol interference and fading jointly.
1 citations
TL;DR: An error in calculating the first and second moments of the "exponential-Rayleigh" distribution appears in a recent paper; this correspondence presents the correct calculations as discussed by the authors. But this correspondence does not address the problem of the first moment of the exponential Rayleigh distribution.
Abstract: An error in calculating the first and second moments of the "exponential-Rayleigh" distribution appears in a recent paper; this correspondence presents the correct calculations.
1 citations
TL;DR: Simulation analysis for an FM system with Rician fading channel shows that a new set of error variance algorithms developed from the filter algorithm assuming a Gaussian distribution for the state estimation errors and taking the effect of high frequency terms into consideration predict the system performance accurately in the threshold region.