CCK demodulation via symbol decision feedback equalizer
AssigneeDSP Group Ltd.
InventorsYounggyun Kim, Jaekyun Moon
Life of this patent
Estimating the term…
Abstract
Demodulation techniques for a wireless communication system make use of a decision feedback equalization (DFE) technique to mitigate the effects of multipath channel characteristics on receiver performance. The techniques may be particularly useful in the demodulation of complementary code keying (CCK) symbols. A demodulator that performs such techniques may include a time-variant or time-invariant matched filter, a feedback intersymbol interference (ISI) canceller, a transform unit, a phase rotation estimator and corrector, a pattern-dependent bias canceller, and a maximum picker for symbol decisions. The transform unit may include a bank of correlators, or alternatively a fast Walsh transform unit.
Claims26
A method comprising:
- generating a feedback signal based on a first symbol decision for a first wireless signal observation;
- applying the feedback signal to a received wireless signal to produced a second wireless signal observation;
- correlating the second wireless observation with a plurality of candidate modulation patterns;
- estimating and correcting a phase rotation for each of the modulation patterns;
- selecting one of the modulation patterns based on a maximum likelihood function;
- and
- generating a second symbol decision based on the estimated phase rotation and the selected modulation pattern.
A wireless communication device comprising:
- a feedback loop that generates a feedback signal based on a first symbol decision for a first wireless signal observation, and applies the feedback signal to a received wireless signal to produced a second wireless signal observation;
- a correlator that correlates the second wireless observation with a plurality of candidate modulation patterns;
- a phase estimator that estimates a phase rotation of each of the modulation patterns;
- a phase corrector that corrects the phase rotation for each of the modulation patterns based on the estimated phase rotation;
- a maximum picker that selects one of the modulation patterns based on a maximum likelihood function;
- and
- a symbol estimator that generates a second symbol decision based on the estimated phase rotation and the selected modulation pattern.
A wireless communication device comprising:
- means for generating a feedback signal based on a first symbol decision for a first wireless signal observation;
- means for applying the feedback signal to a received wireless signal to produced a second wireless signal observation;
- means for correlating the second wireless observation with a plurality of candidate modulation patterns;
- means for estimating and correcting a phase rotation for each of the modulation patterns;
- means for selecting one of the modulation patterns based on a maximum likelihood function;
- and
- means for generating a second symbol decision based on the estimated phase rotation and the selected modulation pattern.
A wireless communication device comprising:
- a receiver to receive a wireless signal;
- a symbol estimator to generate a symbol decision for the received wireless signal;
- and
- a symbol decision feedback equalization system to reduce multipath channel effects on the symbol decision based on past symbol decisions.
Dependencies are inferred from the claim text.