A simplified diversity communication system for beyond-the-horizon links

Altman, F. J.; Sichak, W.

doi:10.1109/tcom.1956.1097266

Cited by 49 publications

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“…A variant of this, suitable for use in systems operating at UHF and above, uses two separated transmitting antennas, one of which transmits vertically polarized radiation and the other of which transmits horizontally polarized radiation, and a single receiving reflector with two feed horns or dipoles to separate the vertical and horizontal received signals. By combining these two methods, Altman and Sichak [8] obtained a fourth-order, bidirectional, full duplex space diversity system that requires only two reflectors at each end, as indicated in Fig. 1.…”

Section: Basic Assumptions and Other Preliminariesmentioning

confidence: 99%

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Linear diversity combining techniques

2003

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This paper provides analyses of three types of diversity combining systems in practical use. These are: selection diversity, maximal-ratio diversity, and equal-gain diversity systems. Quantitative measures of the relative performance (under realistic conditions) of the three systems are provided. The effects of various departures from ideal conditions, such as non-Rayleigh fading and partially coherent signal or noise voltages, are considered. Some discussion is also included of the relative merits of predetection and postdetection combining and of the problems in determining and using long-term distributions. The principal results are given in graphs and tables, useful in system design. It is seen that the simplest possible combiner, the equal-gain system, will generally yield performance essentially equivalent to the maximum obtainable from any quasilinear system. The principal application of the results is to diversity communication systems and the discussion is set in that context, but many of the results are also applicable to certain radar and navigation systems.

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Section: Basic Assumptions and Other Preliminariesmentioning

confidence: 99%

“…However, very few of these have provided quantitative comparative data on the relative performance of the various techniques, especially the two significant techniques (maximal-ratio and equal-gain) investigated since 1954. The major exception to this is a paper by Altman and Sichak [8], which is not widely known and even less understood.…”

Section: Introductionmentioning

confidence: 99%

Linear diversity combining techniques

2003

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“…To find the variance of y[n] under H 1 , it is required to compute the expectations of all the terms in (29). We have, E{z…”

Section: Discussionmentioning

confidence: 99%

Polarity-Coincidence-Array Based Spectrum Sensing for Multiple Antenna Cognitive Radios in the Presence of Non-Gaussian Noise

Wimalajeewa

Varshney

2011

IEEE Trans. Wireless Commun.

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ABSTRACT:One of the main requirements of the cognitive radio (CR) systems is the ability to perform spectrum sensing in a reliable manner in challenging environments that arise due to propagation channels which undergo multipath fading and non-Gaussian noise. While most existing literature on spectrum sensing has focused on impairments introduced by additive white Gaussian noise (AWGN), this assumption fails to model the behavior of certain types of noise in practice. In this paper, the use of a non-parametric and easily implementable detection device, namely polarity-coincidence-array (PCA) detector, is proposed for the detection of weak primary signals with a cognitive radio equipped with multiple antennas. Its performance is evaluated in the presence of heavy-tailed noise. The detector performance in terms of the probabilities of detection and false alarm is derived when the communication channels between the primary user transmitter and the multiple antennas at the cognitive radio are AWGN as well as when they undergo Rayleigh fading. From the numerical results, it is observed that a significant performance enhancement is achieved by the PCA detector compared to that of the energy detector with AWGN as well as fading channels as the heaviness of the tail of the non-Gaussian noise increases. KEYWORDS:Cognitive radio, spectrum sensing, non-Gaussian noise, Rayleigh fading, polarity-coincidencearray detectors AbstractOne of the main requirements of the cognitive radio (CR) systems is the ability to perform spectrum sensing in a reliable manner in challenging environments that arise due to propagation channels which undergo multipath fading and non-Gaussian noise. While most existing literature on spectrum sensing has focused on impairments introduced by additive white Gaussian noise (AWGN), this assumption fails to model the behavior of certain types of noise in practice. In this paper, the use of a non-parametric and easily implementable detection device, namely polarity-coincidence-array (PCA) detector, is proposed for the detection of weak primary signals with a cognitive radio equipped with multiple antennas. Its performance is evaluated in the presence of heavy-tailed noise. The detector performance in terms of the probabilities of detection and false alarm is derived when the communication channels between the primary user transmitter and the multiple antennas at the cognitive radio are AWGN as well as when they undergo Rayleigh fading. From the numerical results, it is observed that a significant performance enhancement is achieved by the PCA detector compared to that of the energy detector with AWGN as well as fading channels as the heaviness of the tail of the non-Gaussian noise increases.

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“…The probability distribution function (pdf) of a dual diversity EGC output in Rayleigh fading [2]. Cumulative distribution function (cdf) of the output envelope of dual-diversity EGC over independent non-identical Rayleigh paths [3].…”

Section: Introductionmentioning

confidence: 99%

Impact of Noise Imbalance on the Performance of Predetection Dual-EGC Receivers Over Rayleigh Fading Channels

Patel

Chaturvedi

2007

IEEE GLOBECOM 2007-2007 IEEE Global Telecommunications Conference

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A new expression for the probability density function of the signal-to-noise ratio (SNR) at the output of a predetection dual-equal-gain-combining (dual-EGC) receiver over independent but non-identical Rayleigh fading paths with different noise levels is derived. A closed-form expression for the average bit error rate (ABER) for coherent binary modulation schemes is also derived. The effect of the degree of noise imbalance on ABER is studied. From the results we determine the ranges of noise imbalance for a given average SNR per path over which the performance of predetection dual-EGC is better or worse than SC and single path receivers.

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A simplified diversity communication system for beyond-the-horizon links

Cited by 49 publications

References 0 publications

Linear diversity combining techniques

Linear diversity combining techniques

Polarity-Coincidence-Array Based Spectrum Sensing for Multiple Antenna Cognitive Radios in the Presence of Non-Gaussian Noise

Impact of Noise Imbalance on the Performance of Predetection Dual-EGC Receivers Over Rayleigh Fading Channels

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