Method of effecting channel estimation for a fading channel when transmitting symbol sequences
AssigneeTelefonaktiebolaget L M Ericsson
InventorLars G. Larsson
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AssigneeTelefonaktiebolaget L M Ericsson
InventorLars G. Larsson
Estimating the term…
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.
A method for effecting channel estimation for a fading channel when transmitting a signal comprising symbol sequences, wherein each of the symbol sequences has at least one synchronizing sequence and one data sequence, said method comprising the steps of:
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