Adaptive channel estimation by means of variation of the integration length during the despreading of spread-coded training symbol sequences
First Claim
1. A method for adaptive channel estimation for the transmission of spread-coded radio signals by reception and evaluation of a training symbol sequence, comprising the steps of:
- a) correlating the received spread-coded signal sequence with the spread-coded training symbol sequence in such a way that the influence of the transmitted training symbols is eliminated,b) despreading the signal sequence which results from the correlation,c) producing a sequence of data symbols by integrating the despread signal sequence over a number of signal values, with the number being set as a function of the channel dynamic range,d) filtering the sequence of data symbols in a digital filter with fixed or variable filter coefficients in order to produce channel estimation values.
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Abstract
In the method, the received spread-coded signal sequence rk(i) is first of all correlated with the spread-coded training symbol sequence in a correlator (24) so as to counteract the influence of the transmitted training symbols. The signal sequence which results from the correlation process is then despread in a despreading apparatus (21, 22). The despread signal sequence is integrated over a number (N_MF) of signal values, with the number (N_MF) being set as a function of the channel dynamic range (λ). The sequence of data symbols produced in this way is filtered with fixed or variable filter coefficients in a digital filter (25) in order to produce channel estimation values ({tilde over (H)}(l)).
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Citations
13 Claims
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1. A method for adaptive channel estimation for the transmission of spread-coded radio signals by reception and evaluation of a training symbol sequence, comprising the steps of:
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a) correlating the received spread-coded signal sequence with the spread-coded training symbol sequence in such a way that the influence of the transmitted training symbols is eliminated, b) despreading the signal sequence which results from the correlation, c) producing a sequence of data symbols by integrating the despread signal sequence over a number of signal values, with the number being set as a function of the channel dynamic range, d) filtering the sequence of data symbols in a digital filter with fixed or variable filter coefficients in order to produce channel estimation values. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for adaptive channel estimation for the transmission of spread-coded radio signals by reception and evaluation of a training symbol sequence, having
a means for correlation of the received spread-coded signal sequence with the spread-coded training symbol sequence in such a way that the influence of the transmitted training symbols is eliminated, a means for despreading of the signal sequence which results from the correlation, a means for integration of the signal sequence which is produced by the despreading means over a number (integration length) of signal values, and for production of a sequence of data symbols, a means for calculation of the number and for supplying the numerical value to the integration means, a digital filter for production of channel estimation values from the sequence of data symbols which is supplied from the integration means, with fixed or variable filter coefficients.
Specification