System and method for ISI based adaptive window synchronization
AssigneeQUALCOMM Incorporated
InventorsHao-ren Cheng, Chih-yuan Chu
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Abstract
This disclosure is directed to systems and methods for positioning a FFT window using the noise power that is related to ISI By selecting a FFT window position that minimizes the noise power, ISI is reduced or eliminated The techniques can be used in coherent and non-coherent systems Further, noise associated with the Doppler effect is compensated for, allowing the use of these system and methods in time-varying environments, such as mobile applications.
Claims19
A method for reducing inter-symbol interference in a multiple sub-carrier digital communication receiver comprising the steps of:
- selecting a plurality of transform window positions;
- transforming a sequence of time domain samples into a sequence of frequency domain symbols, each frequency domain symbol including a plurality of complex values at a plurality of sub-carrier frequencies, using each of the plurality of transform window positions;
- calculating a noise power proportional to a symbol timing offset and associated with each of the plurality of transform window positions;
- and
- determining an optimized transform window position using the calculated noise powers.
An apparatus in a multiple sub-carrier digital communication receiver for optimizing a transform window position, the apparatus comprising a symbol synchronization block configured to calculate a noise power proportional to a symbol timing offset and associated with each of a plurality of transform window positions and to determine an optimized transform window position using the calculated noise powers and a transform block configured to transform a sequence of time domain samples into a sequence of frequency domain symbols, each frequency domain symbol including a plurality of complex values at a plurality of sub-carrier frequencies, using the optimized transform window position.
Dependencies are inferred from the claim text.