Positioning techniques for narrowband wireless signals under dense multipath conditions
First Claim
1. A method comprising:
- receiving, at a wireless device, signals that are transmitted at different times, each of the signals having a different carrier frequency and representing a different subchannel of a wireless channel;
determining estimated magnitudes of the subchannels based respectively on the signals;
determining estimated group delays of the subchannels based respectively on the signals, wherein determining the estimated group delays comprises computing phase angles of a respective subchannel of the subchannels based on a Fourier transformation of a respective signal of the signals and a Fourier transformation of a reference signal, and applying a fit function to the phase angles to produce an estimated group delay of the respective subchannel;
determining an estimated channel frequency response of the wireless channel based on the estimated magnitudes and the estimated group delays;
determining a propagation delay of the signals based on the estimated channel frequency response; and
generating position information based on the propagation delay.
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Abstract
Techniques and systems for position determination using narrowband signals are disclosed. A disclosed technique includes receiving, at a wireless device, signals that are transmitted at different times, each of the signals having a different carrier frequency and representing a different subchannel of a wireless channel; determining estimated magnitudes of the subchannels based respectively on the signals; determining estimated group delays of the subchannels based respectively on the signals; determining an estimated channel frequency response of the wireless channel based on the estimated magnitudes and the estimated group delays; determining a propagation delay of the signals based on the estimated channel frequency response; and generating position information based on the propagation delay.
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Citations
23 Claims
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1. A method comprising:
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receiving, at a wireless device, signals that are transmitted at different times, each of the signals having a different carrier frequency and representing a different subchannel of a wireless channel; determining estimated magnitudes of the subchannels based respectively on the signals; determining estimated group delays of the subchannels based respectively on the signals, wherein determining the estimated group delays comprises computing phase angles of a respective subchannel of the subchannels based on a Fourier transformation of a respective signal of the signals and a Fourier transformation of a reference signal, and applying a fit function to the phase angles to produce an estimated group delay of the respective subchannel; determining an estimated channel frequency response of the wireless channel based on the estimated magnitudes and the estimated group delays; determining a propagation delay of the signals based on the estimated channel frequency response; and generating position information based on the propagation delay. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method comprising:
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receiving, at a wireless device, narrowband signals transmitted over a wireless channel, each narrowband signal having a frequency that is different from frequencies of the other narrowband signals, each narrowband signal representing a subchannel of the wireless channel; estimating, by the wireless device, a subchannel frequency response for each narrowband signal, wherein estimating the subchannel frequency response comprises computing a group delay by determining a phase difference between the received narrowband signal and the transmitted narrowband signal, and integrating the group delay to obtain an approximated phase component; estimating, by the wireless device, a wireless channel frequency response based on the subchannel frequency responses; and estimating, by the wireless device, a propagation delay of the narrowband signals based on the wireless channel frequency response. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A device comprising:
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a receiver configured to receive signals that are transmitted at different times, each of the signals having a different carrier frequency and representing a different subchannel of a wireless channel; and a processor coupled with the receiver, wherein the processor is configured to determine estimated magnitudes of the subchannels based respectively on the signals, determine estimated group delays of the subchannels based respectively on the signals, determine an estimated channel frequency response of the wireless channel based on the estimated magnitudes and the estimated group delays, determine a propagation delay of the signals based on the estimated channel frequency response, and generate position information based on the propagation delay, wherein the processor is configured to compute phase angles of a respective subchannel of the subchannels based on a Fourier transformation of a respective signal of the signals and a Fourier transformation of a reference signal, and apply a fit function to the phase angles to produce an estimated group delay of the respective subchannel. - View Dependent Claims (16, 17)
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18. A device comprising:
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a receiver configured to receive narrowband signals that are transmitted at different times, each narrowband signal having a frequency that is different from frequencies of the other narrowband signals, each narrowband signal representing a subchannel of the wireless channel; and a processor coupled with the receiver, wherein the processor is configured to perform operations comprising; estimating a subchannel frequency response for each narrowband signal, wherein estimating the subchannel frequency response comprises computing a group delay by determining a phase difference between the received narrowband signal and the transmitted narrowband signal, and integrating the group delay to obtain an approximated phase component; estimating a wireless channel frequency response based on the subchannel frequency responses; and estimating a propagation delay of the narrowband signals based on the wireless channel frequency response. - View Dependent Claims (19, 20, 21, 22, 23)
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Specification