DocumentCode :
803677
Title :
Use of DS/SS signaling to mitigate Rayleigh fading in a dense scatterer environment
Author :
Amoroso, Frank
Author_Institution :
Omnipoint Corp., Colorado Springs, CO, USA
Volume :
3
Issue :
2
fYear :
1996
fDate :
4/1/1996 12:00:00 AM
Firstpage :
52
Lastpage :
61
Abstract :
The issues discussed are summarised by a minimal checklist which should be applied to any DS/SS link architecture for use in a dense scatterer environment. For effective mitigation of fading the chip interval T, should be at most equal to the RMS delay spread Δ, indeed preferably much smaller. For minimal intersymbol interference the symbol duration Ts should be much longer than Δ. On a fast-moving antenna platform the distance traversed by the antenna during one symbol interval should be much less than 0.38 λ. Otherwise, coherent symbol correlation becomes difficult, and a high irreducible error rate may result. The so-called mean bit error rates are just that. They are probabilistic means over the full range of antenna travel. If the antenna tends to remain stationary or travel very slowly, then perhaps it is more meaningful to speak of the maximum (or worst-case) error rate over a specified large fraction of all antenna locations. The chip stream should be as random as possible; that is, the chip values should be statistically uncorrelated. A chip-matched filter, adaptive to the continual metamorphoses of the arriving chip pulse shape and the mean chip arrival time, is essential to symbol detection at those frequently occurring antenna locations where the received power is a minimum, dispersion is a maximum, and the chip pulses arrive with essentially zero mean value. Such situations crop up roughly once per wavelength of antenna travel. In DPSK signaling the matched filter could be as simple as a single time delay of duration Ts
Keywords :
Rayleigh channels; adaptive filters; differential phase shift keying; electromagnetic wave scattering; error statistics; fading; filtering theory; intersymbol interference; land mobile radio; matched filters; multipath channels; pseudonoise codes; radiofrequency interference; radiowave propagation; spread spectrum communication; DPSK signalling; DS/SS link architecture; DS/SS signaling; RMS delay spread; Rayleigh fading; adaptive chip matched filter; antenna locations; chip interval; chip pulse shape; chip stream; coherent symbol correlation; dense scatterer environment; dispersion; fast moving antenna platform; intersymbol interference; irreducible error rate; maximum error rate; mean bit error rates; mean chip arrival time; multipath; probabilistic means; received power; symbol detection; symbol duration; Adaptive arrays; Adaptive filters; Bit error rate; Delay effects; Error analysis; Intersymbol interference; Pulse shaping methods; Rayleigh channels; Rayleigh scattering; Shape;
fLanguage :
English
Journal_Title :
Personal Communications, IEEE
Publisher :
ieee
ISSN :
1070-9916
Type :
jour
DOI :
10.1109/98.490752
Filename :
490752
Link To Document :
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