Showing papers on "Fading distribution published in 1973"
TL;DR: A simple device to simulate the Rayleigh distributed fast fading encountered in mobile radio is described and a design is given whose performance is shown to agree very closely with theory.
Abstract: A simple device to simulate the Rayleigh distributed fast fading encountered in mobile radio is described and evaluated. The Rayleigh envelope statistics are obtained by adding two independent Gaussian noise sources in quadrature. The theoretical spectrum of the received signal is approximated by shaping the spectrum of the noise sources with filters. A design is given whose performance is shown to agree very closely with theory.
102 citations
TL;DR: A simple device to simulate the Rayleigh distributed fast fading encountered in mobile radio is described and a design is given whose performance is shown to agree very closely with theory.
Abstract: A simple device to simulate the Rayleigh distributed fast fading encountered in mobile radio is described and evaluated. The Rayleigh envelope statistics are obtained by adding two independent Gaussian noise source in quadrature. The theoretical spectrum of the received signal is approximated by shaping the spectrum of the noise sources with filters. A design is given whose performance is shown to agree very closely with theory.
52 citations
TL;DR: It is shown that on moderately dispersive channels the equalizer nearly achieves optimum one-shot performance, and an adaptive version of this equalizer exists, this means data transmission on slowly fading channels is possible at rates above the natural rate suggested by the channel dispersion spread without bandwidth expansion and with small intersymbol interference penalty.
Abstract: The reception and detection of a single digit under known channel conditions are investigated. The probability of error for an optimum one-shot receiver instantaneously matched to the channel state is averaged over an ensemble of dispersive diversity channels. The average probability of error as a function of energy to noise ratio is found to be solely dependent on the ratio of rms dispersion width to data symbol width. For these dispersive channels an implicit diversity effect is qualitatively explained in terms of eigenvalues that depend on the ensemble statistic. The one-shot receiver performance provides a bound for practical receivers. In a comparison with a decision feedback equalizer, it is shown that on moderately dispersive channels the equalizer nearly achieves optimum one-shot performance. Since an adaptive version of this equalizer exists, this means data transmission on slowly fading channels is possible at rates above the natural rate suggested by the channel dispersion spread without bandwidth expansion and with small intersymbol interference penalty. The use of one-shot receiver performance curves can also be used as estimates of equalizer performance in situations where computation of the latter is impractical.
40 citations
TL;DR: A novel feature of selective diversity is that, for moderate SNR, the error probability decreases to zero as a strong inverse power of L , the order of diversity, which contrasts with behavior of conventional systems in which increasing L causes the error probabilities to decrease to a nonzero lower bound.
Abstract: A feedback scheme for regulating error probability on slowly fading communication channels is described and analyzed. In this selective diversity system, only the best R of L available diversity subchannels are used, the selection being revised from moment to moment. Comparison with conventional diversity transmission on an 8-channel system shows a performance improvement ranging from 20.8 to 9.5 dB, where the low figure corresponds to constant power operation of the transmitter and a typical value of round-trip delay. A novel feature of selective diversity is that, for moderate SNR, the error probability decreases to zero as a strong inverse power of L , the order of diversity, which contrasts with behavior of conventional systems in which increasing L causes the error probability to decrease to a nonzero lower bound. The implication is that the figures quoted above can be improved indefinitely by increasing the order of diversity.
28 citations
TL;DR: A bound on the probability of error is obtained for an M -ary direct-detection optical communications system consisting of an amplitude-stabilized source, a lognormal atmospheric channel, and a photocounting detector array.
Abstract: A bound on the probability of error is obtained for an M -ary direct-detection optical communications system consisting of an amplitude-stabilized source, a lognormal atmospheric channel, and a photocounting detector array. Equal-energy, equiprobable, orthogonal signaling, and fiat independent fading at all detectors is assumed. The result reduces to that obtained previously in the absence of fading. A comparison is made with the analogous solution for the heterodyne array receiver.
5 citations
TL;DR: A performance analysis of a digital radio-relay system during fading periods, and results seem to indicate the feasibility of the frequency reuse technique.
Abstract: The planning of a digital radio network requires an evaluation of the effect of quite a large number of interfering sources. These in turn are dependent upon many parameters, such as the network structure, channel arrangement, antenna patterns, and so on. This paper presents a performance analysis of a digital radio-relay system during fading periods. The possibility of attaining a required fading margin is analyzed when many co-channel and interchannel interferences are simultaneously present, both for long-haul and shorthaul radio relay systems. A comparison is presented between two possible techniques for the reusing of the same frequency band in each hop, by taking advantage of the cross-polarization discrimination (XPD). The reduction of the XPD expected during fading periods is also taken into account. Binary and quaternary coherent PSK modulations are considered, with realizable filters (of the Butterworth type), both at the transmitter and at the receiver. The error probability calculations were performed with a combined analytical and computer simulation approach. The results seem to indicate the feasibility of the frequency reuse technique.
5 citations
01 Aug 1973
3 citations
TL;DR: In this paper, the total bit-error probability using square-law detection of an on-off keyed carrier received through a fading medium is calculated, and it is shown that the use of diversity will recover much of the performance loss caused by the fading, provided that an optimum decision threshold is used.
Abstract: In this paper the total bit-error probability using square-law detection of an on-off keyed carrier received through a fading medium is calculated. It is shown that the use of diversity will recover much of the performance loss caused by the fading, provided that an optimum decision threshold is used. Consideration is given to the performance obtained with a fixed optimum threshold (depending only on the mean-square signal strength) and to that obtained with two forms of variable threshold, assumed to follow the instantaneous fading signal strength. Compared to the fixed optimum threshold, the best variable threshold results in a 5- or 2.5-dB reduction in the required rms SNR for a 10-4error rate with two- or four-branch diversity, respectively; as compared to the no fading case, use of the fixed threshold requires 3 dB more SNR for a 10-4error rate with four-branch diversity, and requires 32 dB more SNR if only a single branch is used. A calculation of the average fade duration of the diversity-combiner output-signal component shows that diversity reduces the average time that the signal component spends below the threshold according to N-1/2for N branches. This is true for both the fixed or the best variable threshold, but the average duration with the fixed threshold is larger by about [log (1+σ ρ 2)]1/2, where σ ρ 2is the mean-square SNR per branch.
1 citations
TL;DR: A feedback-rate control scheme recently proposed by Cavers for the incoherent detection of binary signals transmitted over a slowly fading Rayleigh channels is shown to be optimum for coherent systems.
Abstract: A feedback-rate control scheme recently proposed by Cavers for the incoherent detection of binary signals transmitted over a slowly fading Rayleigh channels is shown to be optimum for coherent systems