Pulse or digital communications – Repeaters – Testing
Patent
1990-12-03
1993-04-20
Safourek, Benedict V.
Pulse or digital communications
Repeaters
Testing
375 94, H04L 2701
Patent
active
052048780
ABSTRACT:
Symbols in a symbol sequence transmitted via a fading channel are estimated in an equalizer having a channel estimating filter. An error signal influences an adaptation circuit which controls adjustable coefficients so as to form a channel estimate, which is adapted during the whole of the symbol sequence. The adaptation circuit performs an adaptation algorithm, which is influenced by mean energy values obtained from the channel estimate in a mean-value-forming circuit. Subsequent to fading the adaptation algorithm is able to control the coefficients so that one of the coefficients will erroneously dominate the channel estimate, with erroneous estimation of symbols as a result. This is counteracted by selecting the largest of the mean energy values, this largest value influencing the adaptation algorithm. When the signal strength of the transmitted symbols falls beneath a threshold value, the coefficient which dominated the channel estimate, for instance the first coefficient is sustained to also dominate after fading and the remaining coefficients are set to zero.
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Safourek Benedict V.
Telefonaktiebolaget L M Ericsson
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