Abstract: Various embodiments relate to a method for estimating a breathing rate, including: receiving a plurality of channel state information (CSI) from a wireless device; selecting an initial reference CSI from the plurality of CSI; computing a perturbation index using the initial reference CSI and a portion of the plurality of CSI; determining an optimal reference CSI based upon the perturbation index; re-computing the perturbation index using the optimal reference CSI on a portion of the plurality of CSI subsequent to the optimal reference CSI; and determining a breathing rate from the perturbation index using a frequency analysis of the perturbation index.

Abstract: This disclosure describes systems and methods for detecting motion based on channel correlation in wireless communication signals. A receiver at a first wireless communication device is capable of wirelessly communicating with a second wireless communication device. The first wireless communication device is configured to receive from the second wireless communication device via two or more subcarriers a first packet and a channel correlation for the first packet across the two or more subcarriers. Control circuitry is configured to estimate a channel energy difference for the receiver based on the channel correlation for the first packet. A motion detection decision is then made based on the estimated channel energy difference.

Abstract: This disclosure describes systems and methods for detecting motion based on channel correlation in wireless communication signals. A receiver at a first wireless communication device is capable of wirelessly communicating with a second wireless communication device. The first wireless communication device is configured to receive from the second wireless communication device via two or more subcarriers a first packet and a channel correlation for the first packet across the two or more subcarriers. Control circuitry is configured to estimate a channel energy difference for the receiver based on the channel correlation for the first packet. A motion detection decision is then made based on the estimated channel energy difference.

Abstract: Embodiments described herein provide a method for detecting motion. At a first wireless communication device capable of wirelessly communicating with a second wireless communication device, channel state information (CSI) for the wireless channel between the first and second wireless communication devices is received. A nulling matrix is calculated based on the received CSI. The calculated nulling matrix is applied to a plurality of short packets scheduled to be periodically transmitted from the first wireless communication device to the second wireless communication device. The first wireless communication device receives, from the second wireless communication device, received signal strength information (RSSI) determined for each of the transmitted plurality of short packets. The method further includes detecting motion based on detecting a change in the RSSI received from the second wireless communication device.

Abstract: Embodiments described herein provide a method for detecting motion. At a first wireless communication device capable of wirelessly communicating with a second wireless communication device, channel state information (CSI) for the wireless channel between the first and second wireless communication devices is received. A nulling matrix is calculated based on the received CSI. The calculated nulling matrix is applied to a plurality of short packets scheduled to be periodically transmitted from the first wireless communication device to the second wireless communication device. The first wireless communication device receives, from the second wireless communication device, received signal strength information (RSSI) determined for each of the transmitted plurality of short packets. The method further includes detecting motion based on detecting a change in the RSSI received from the second wireless communication device.

Abstract: Systems, methods, and other embodiments associated with estimating noise in a receiver device based on related properties of order statistics are described. According to one embodiment, a method includes generating an initial set of magnitude squared values from a time domain impulse response of a receiver device. The method also includes generating an initial noise power estimate based on a modified set of magnitude squared values and generating a threshold value based on the initial noise power estimate. The method generates a final noise power estimate by averaging values of the initial set of magnitude squared values that are less than the threshold value and removing a thresholding bias from the resulting average.

Abstract: Systems, apparatus and methods are provided for detecting the mode of a received OFDM signal. A received signal may be correlated with one or more time-delayed version of itself resulting in a set of correlation signals. Each correlation signal may be analyzed for one or more characteristics that can be used to determine the symbol length of the received signal. In order to minimize the number of correlations performed, one or more correlations can be used with varying symbol lengths and a fixed guard interval length. The correlation signals can be processed by filters, and the characteristics of the filtered correlation signals can be analyzed to determine the guard interval length of the received signal. In addition to detecting symbol length, the present invention can be used to detect receiver impairment and perform any appropriate compensations.

Abstract: A control system including a DC/DC converter and a control module. The DC/DC converter includes a first inductor and a second inductor. The DC/DC converter is configured to i) receive a first DC voltage and ii) output a second DC voltage. The control module is configured to, during a first operation mode, charge the first inductor while discharging the second inductor, and, during a second operation mode, one of i) charge the first inductor while charging the second inductor and ii) discharge the first inductor while discharging the second inductor. The control module is further configured to initiate the second operation mode in response to detecting a current transient in the DC/DC converter.

Abstract: A digital signal processor includes an up-sampling module that samples an input signal and generates up-sampling points. A natural sampling module includes a reference signal generation module that generates a reference signal. A crossing point detection module receives the up-sampling points and the reference signal and uses interpolation to detect intersection points of the input signal and the reference signal. The crossing point detection module determines values of the input signal at first and second evaluation times. The crossing point detection module estimates a current intersection point of the input signal and the reference signal as an intersection of the reference signal and a line that extends between first and second points on the input signal that correspond with the first and second evaluation times. A frequency of the reference signal is variable and a current switching period of the reference signal is not equal to a previous switching period.

Abstract: Systems and techniques relating to image cancellation in received communications signals are described. A described technique includes receiving a communications signal including a desired signal and an image signal; generating a leakage tracing signal at a frequency band of the image signal, the leakage tracing signal including a noise signal, a frequency of the leakage tracing signal being within the frequency band of the image signal; and removing the image signal from a signal that is based on the communications signal and the leakage tracing signal to resolve the desired signal, where the removing is based on an addition of the leakage tracing signal to the communications signal. Removing the image signal can include using one or more weights to control one or more filters to resolve the desired signal. The one or more weights can be determined based on the noise signal.

Abstract: Systems, apparatus and methods are provided for detecting the mode of a received OFDM signal. A received signal may be correlated with one or more time-delayed version of itself resulting in a set of correlation signals. Each correlation signal may be analyzed for one or more characteristics that can be used to determine the symbol length of the received signal. In order to minimize the number of correlations performed, one or more correlations can be used with varying symbol lengths and a fixed guard interval length. The correlation signals can be processed by filters, and the characteristics of the filtered correlation signals can be analyzed to determine the guard interval length of the received signal. In addition to detecting symbol length, the present invention can be used to detect receiver impairment and perform any appropriate compensations.

Abstract: A system includes a first buffer configured to receive data at a first rate, and output the data at a second rate. A processing module configured to receive the data from the first buffer at the second rate, convert the data into processed data, and output the processed data at a third rate. A second buffer is configured to receive the processed data from the processing module at the third rate, and output the processed data at a fourth rate. The third rate is faster than the fourth rate to avoid a buffer underflow condition in the second buffer. In response to the second buffer reaching a predetermined capacity, the processing module is further configured to enter into a break state in which the processing module temporarily stops both receiving data from the first buffer and outputting the processed data and adjusts the second rate to avoid a buffer overrun condition in the first buffer.

Abstract: A control system comprises a DC/DC converter that includes first and second inductances, that receives a first DC voltage and that generates a second DC voltage. A control module selectively charges or discharges the first inductance while discharging or charging the second inductance during a first mode and one of charges both of the first and second inductances or discharges both of the first and second inductances during a second mode.

Abstract: Systems and techniques relating to image cancellation in received communications signals are described. In one aspect, a received communications signal can include a desired signal and an image signal. A leakage tracing signal can be generated, and the image signal can be removed from the communications signal using the leakage tracing signal mixed with the communications signal. Implementations can include generating a first channel signal and a second channel signal, generating a first filter using the first channel signal and the leakage tracing signal, and generating a second filter using the second channel signal and the leakage tracing signal. Removing the image signal from the communications signal can include filtering the first channel signal using the second filter to obtain a first filtered signal, filtering the second channel signal using the first filter to obtain a second filtered signal, and subtracting the second filtered signal from the first filtered signal.

Abstract: A control system comprises a DC/DC converter that includes first and second inductances, that receives a first DC voltage and that generates a second DC voltage. A control module selectively charges or discharges the first inductance while discharging or charging the second inductance during a first mode and one of charges both of the first and second inductances or discharges both of the first and second inductances during a second mode.

Abstract: An input/output data rate synchronization system includes a first data buffer that receives input data at a first rate, that temporarily stores the input data, and that outputs the input data at a second rate. A data processing module receives the input data from the first data buffer and outputs processed data at a third rate. A second data buffer receives the processed data from the data processing module at the third rate, temporarily stores the processed data, and outputs the processed data at a fourth rate. The data processing module temporarily stops receiving the input data and generating the processed data when the second data buffer exceeds a first predetermined capacity. The data processing module increases the second rate when the first data buffer exceeds a second predetermined capacity and decreases the second rate when a difference between the second and first rates is greater than a predetermined rate.

Abstract: A control system comprises a DC/DC converter that includes first and second inductances, that receives a first DC voltage and that generates a second DC voltage. A control module selectively charges or discharges the first inductance while discharging or charging the second inductance during a first mode and one of charges both of the first and second inductances or discharges both of the first and second inductances during a second mode.

Abstract: A closed-loop control system for a DC/DC converter includes a DC/DC converter that receives a first DC voltage and that generates a second DC voltage. The DC/DC converter includes first and second inductances. A control module receives the second DC voltage and generates at least one control signal to one of charge or discharge the first and second inductances. The control module has first and second modes. During the first mode the control module alternately charges one of the first and second inductances and discharges the other of the first and second inductances. During the second mode the control module one of charges or discharges both of the first and second inductances. The control module initiates the second mode when a transient condition occurs in the DC/DC converter. The transient condition is based on one of the second DC voltage and current through an output capacitance in the DC/DC converter.

Abstract: A closed-loop control system for a DC/DC converter includes a DC/DC converter that receives a first DC voltage and that generates a second DC voltage. The DC/DC converter includes first and second inductances. A control module receives the second DC voltage and generates at least one control signal to one of charge or discharge the first and second inductances. The control module has first and second modes. During the first mode the control module alternately charges one of the first and second inductances and discharges the other of the first and second inductances. During the second mode the control module one of charges or discharges both of the first and second inductances. The control module initiates the second mode when a transient condition occurs in the DC/DC converter. The transient condition is based on one of the second DC voltage and current through an output capacitance in the DC/DC converter.