CDMA demodulator and demodulation method
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United States of America Patent
Stats
-
Dec 2, 1997
Grant Date -
N/A
app pub date -
Nov 22, 1995
filing date -
Jun 23, 1994
priority date (Note) -
In Force
status (Latency Note)
Importance
Abstract
A CDMA demodulator which can follow fast fading, and reduce interference components from other users in the same cell. A received input spread signal is despread by an orthogonal filer (103). The orthogonal filer provides the input spread signal with successive delays each of an amount of 1/m of the chip interval of a spreading code, multiplies the delayed signals by tap coefficients, and sums up the products, thereby outputting the despread signal. Pilot symbols in the despread signal are compared with known pattern pilot symbols by an absolute phase estimator/phase error compensator (107) to obtain phase fluctuations of the received pilot symbols. The phase fluctuations are interpolated to each information symbol, and each information symbol is phase compensated. The phase compensated information symbols are decided by a decision block (108). The tap coefficients are calculated by a tap coefficient controller (110) so that the mean square error of differences between signals before and after the decision is kept minimum, and the calculated values are fed back to the orthogonal filter.
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