US 10,502,810 B1 · Non-linear phase compensation

Abstract

Systems and techniques for compensating for non-linear phase responses and resulting frequency-dependent group delay using data for a specific device are described. The error in the delay value of a channel determined from a received data packet due to frequency-dependent group delay is removed by subtracting a delay value determined from measurements of a specific device from the delay value of the channel. Furthermore, compensated delay values are calculated for multiple training fields in the received data packet, enabling combining of delay values determined from different training fields that may operate at different frequencies (e.g., with different subcarriers). Hence, the systems and techniques described herein are suitable to provide accurate timing estimates that support calculations for location services, including sub-meter location of a device using a wireless network.

Claims20

Dependent claims

A method of compensating for non-linear phase of a filter, the method comprising:

receiving a data packet;
determining, for a plurality of frequencies, channel frequency response values from a training field of the data packet, the plurality of frequencies being a subset of frequencies in a tone map;
forming an inner product of the channel frequency response values and a shifted version of the channel frequency response values;
determining a first delay value based on an angle of the inner product;
obtaining pre-determined frequency response values indicative of a non-linear phase response;
determining a second delay value from at least some of the pre-determined frequency response values, each of the at least some of the pre-determined frequency response values determined for a respective one of the plurality of frequencies in the tone map;
and
subtracting the second delay value from the first delay value to form a compensated delay value.

5 more elements

A device for compensating for non-linear phase of a filter, the device comprising:

a phase roll module configured to:
determine, for a plurality of frequencies, channel frequency response values from a training field of a data packet received by the device, the plurality of frequencies being a subset of frequencies in a tone map;
form an inner product of the channel frequency response values and a shifted version of the channel frequency response values;
determine a first delay value based on an angle of the inner product;
a calibration module configured to obtain frequency response values indicative of a non-linear phase response of a data path of the device;
a tone frequency module configured to select a subset of the frequency response values that correspond to the plurality of frequencies in the tone map;
a non-linear phase module configured to determine a second delay value from the subset of frequency response values;
and
a delay compensation module configured to subtract the second delay value from the first delay value to form a compensated delay value.

6 more elements

Dependencies are inferred from the claim text.

Non-linear phase compensation

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Non-linear phase compensation

Life of this patent

Abstract

Claims20