Abstract: In a general aspect, detected motion is localized based on channel response characteristics. In some aspects, channel responses based on wireless signals transmitted through a space between wireless communication devices are obtained. A motion detection process is executed to detect motion of an object in the space based on the channel responses, and the channel responses are analyzed to identify a location of the detected motion within one of a plurality of regions within the space.

Abstract: In a general aspect, a wireless communication channel is selected based on signal quality metrics. In some aspects, a first wireless communication device receives a first set of signals based on wireless signals transmitted through a space on a set of wireless communication channels from a second wireless communication device. A signal quality metric value is computed for each wireless communication channel based on the first set of signals, and one of the wireless communication channels is selected based on a comparison of the signal quality metric values for the respective wireless communication channels. The first wireless communication device receives a second set of signals based on wireless signals transmitted through the space on the selected wireless communication channel from the second wireless communication device, and a motion detection process is executed to detect motion of an object in the space based on the second set of signals.

Abstract: In a general aspect, a wireless communication channel is selected based on signal quality metrics. In some aspects, a first wireless communication device receives a first set of signals based on wireless signals transmitted through a space on a set of wireless communication channels from a second wireless communication device. A signal quality metric value is computed for each wireless communication channel based on the first set of signals, and one of the wireless communication channels is selected based on a comparison of the signal quality metric values for the respective wireless communication channels. The first wireless communication device receives a second set of signals based on wireless signals transmitted through the space on the selected wireless communication channel from the second wireless communication device, and a motion detection process is executed to detect motion of an object in the space based on the second set of signals.

Abstract: In a general aspect, a wireless communication channel is selected based on signal quality metrics. In some aspects, a first wireless communication device receives a first set of signals based on wireless signals transmitted through a space on a first wireless communication channel from a second wireless communication device. A signal quality metric value is computed based on the first set of signals, and a second wireless communication channel is selected based on a determination that the value of the signal quality metric does not meet a quality criterion for a motion detection process. The first wireless communication device receives a second set of signals based on wireless signals transmitted through the space on the second wireless communication channel from the second wireless communication device, and the motion detection process is executed to detect motion of an object in the space based on the second set of signals.

Abstract: In a general aspect, the radio state of a wireless communication device is controlled. In some aspects, a first set of motion detection signals is processed by operation of a radio subsystem of a wireless communication device in a first radio state. An amount of variation in the first set of motion detection signals is determined based on values of a parameter of the motion detection signals. A counter is updated in response to a determination that the variation is greater than a first threshold, and the radio subsystem is changed to a second radio state based on comparing the value of the counter with a second threshold. A motion detection process is executed to detect motion of an object in the space based on a second set of motion detection signals processed by operation of the radio subsystem in the second radio state.

Abstract: In a general aspect, motion detected using wireless signals is categorized. In some aspects, frequency response signals are obtained. The frequency response signals are based on wireless signals that were transmitted through a space and received at a wireless sensor device over a time period. Values of a statistical parameter are determined for the time period, with the statistical parameter for the time period being based on a function applied to frequency components of the frequency response signals over the time period. A category of motion that occurred in the space during the time period is identified based on the values of the statistical parameter.

Abstract: In a general aspect, motion is detected by processing wireless signals using stored modem parameters. In some aspects, stored modem parameters are accessed from a memory of a wireless sensor device. The stored modem parameters represent a radio state previously used by a radio subsystem of the wireless sensor device in processing a first motion detection signal. The stored modem parameters are applied to the radio subsystem of the wireless sensor device, a second motion detection signal is processed at the wireless sensor device using the radio state represented by the stored modem parameters, and motion is detected based on the first and second motion detection signals.

Abstract: In a general aspect, motion of an object is detected based on wireless signals. In some aspects, a receiver in a space receives wireless signals; the wireless signals are based on transmissions of a reference signal by a transmitter. Each of the received wireless signals is based on a respective transmission of the reference signal at a distinct time. Channel responses are determined based on the received wireless signals and the reference signal. Each channel response is determined based on a respective one of the received wireless signals. Motion of an object in the space is detected based on the channel responses.

Abstract: In a general aspect, motion is detected based on wireless signals. In some aspects, a modulation type of a first signal is identified at a motion detector device. The first signal is based on a wireless signal transmitted through a space by a transmitter device and received by the motion detector device. A demodulator at the motion detector device generates a second signal from the first signal by demodulating the first signal according to the identified modulation type. A modulator at the motion detector device generates a third signal from the second signal by modulating the second signal according to the identified modulation type. A channel response is generated based on the first signal and the third signal. The channel response is used to detect motion of an object in the space.

Abstract: A method for controlling a transmitter power control system in communication networks that include a modulation scheme having a non-constant amplitude envelope. The method includes generating a transmission signal and transitioning the transmission signal from a first specified power level to a second specified power level and having a transition period therebetween, and generating a constant amplitude envelope modulation of the transmission signal during the transition period. The method may further include generating a non-constant amplitude envelope modulation of the transmission signal at the first specified power level, switching to the constant amplitude envelope modulation of the transmission signal during the transition period and generating the non-constant amplitude envelope modulation of the transmission signal at the second specified power level. A mobile communication device may be used to perform the method.

Abstract: Function approximation circuitry approximates an arbitrary function F over discrete inputs. Discrete values of the function F are stored in a lookup table (LUT) component for various inputs. An addressing module generates an address from an input. An interpolation factor module generates an interpolation factor from the input. An interpolation module generates an output, which is an approximate value of the function F for the input, from the interpolation factor, and from outputs of the LUT component when the LUT component is addressed by the address.

Abstract: A system and method of pre-distorting a signal applied to a power amplifier to compensate for distortion introduced by the power amplifier at different power settings, comprising pre-distorting the signal according to a pre-distortion polynomial, prior to amplification of the signal by the power amplifier; adaptively estimating and applying pre-distortion polynomial coefficients to the pre-distorter by saving successive iterations of adaptive estimation of the pre-distortion polynomial coefficients; and regularizing estimation of the pre-distortion polynomial coefficients over successive iterations according to a modified objective function that initially constrains growth in the magnitude of the pre-distortion polynomial coefficients and then relaxes the constraint in growth over successive iterations until estimation is reduced to a steady-state least squares estimation.

Abstract: A pre-distortion method. A signal to be transmitted Tx is pre-distorted to compensate for nonlinearities of a transmitter. The pre-distorted signal is filtered by an EBEE filter and a baseband filter. The EBEE filter has a filter characteristic of that cancels the baseband filter response over the range of frequencies from a first corner frequency of the baseband filter to a frequency of N*fB where N is a highest order of distortion component being cancelled and fB is the bandwidth of the original signal to be transmitted. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Abstract: A system and method for controlling envelope tracking in a transmitter with closed loop power control, including up-converting and pre-amplifying a baseband signal to a pre-amplified RF signal, amplifying the pre-amplified RF signal, converting the envelope of the baseband signal into a shaped envelope signal, adjusting the gain of the pre-amplified RF signal, and adjusting the shape of the envelope signal in response to changes in the gain of the pre-amplified RF signal.

Abstract: A mobile wireless communications device may include a processor configured to generate a baseband signal, a modulator coupled downstream from the processor, a power amplifier coupled downstream from the modulator, an antenna, and a tunable antenna matching network coupled between the power amplifier and the antenna and configured to match an impedance of the antenna and thereby causing a phase change in an output from the antenna. The processor may be configured to provide upstream phase change compensation in the baseband signal for the phase change in the output from the antenna.

Abstract: A pre-distortion method. A signal to be transmitted Tx is pre-distorted to compensate for nonlinearities of a transmitter. The pre-distorted signal is filtered by an EBEE filter and a baseband filter. The EBEE filter has a filter characteristic of that cancels the baseband filter response over the range of frequencies from a first corner frequency of the baseband filter to a frequency of N*fB where N is a highest order of distortion component being cancelled and fB is the bandwidth of the original signal to be transmitted. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Abstract: A system and method for method of pre-distorting a signal applied to a power amplifier to compensate for distortion introduced by the power amplifier at different power settings, comprising pre-distorting the signal according to a pre-distortion polynomial, prior to amplification of the signal by the power amplifier; adaptively estimating and applying pre-distortion polynomial coefficients to the pre-distorter by saving successive iterations of adaptive estimation of the pre-distortion polynomial coefficients; and regularizing estimation of the pre-distortion polynomial coefficients over successive iterations according to a modified objective function that initially constrains growth in the magnitude of the pre-distortion polynomial coefficients and then relaxes the constraint in growth over successive iterations until estimation is reduced to a steady-state least squares estimation.

Abstract: In a radio receiver, a method of reducing second order distortion components, involves at a first mixer, mixing an input signal with an oscillator signal to generate an I component of a received radio signal; at a second mixer, mixing the input signal with a phase shifted oscillator signal to generate a Q component of the received radio signal; where the I and Q components of the received signal have a receive bandwidth; computing an estimate of second order distortion components as a power output of the I and Q components between approximately the receive bandwidth and twice the receive bandwidth of the received radio signals; and adjusting an operational parameter of the radio receiver to reduce the estimated value of second order distortion components. This abstract is not to be considered limiting.

Abstract: A system and method for controlling envelope tracking in a transmitter with closed loop power control, including up-converting and pre-amplifying a baseband signal to a pre-amplified RF signal, amplifying the pre-amplified RF signal, converting the envelope of the baseband signal into a shaped envelope signal, adjusting the gain of the pre-amplified RF signal, and adjusting the shape of the envelope signal in response to changes in the gain of the pre-amplified RF signal.

Abstract: In a radio receiver, a method of reducing second order distortion components, involves at a first mixer, mixing an input signal with an oscillator signal to generate an I component of a received radio signal; at a second mixer, mixing the input signal with a phase shifted oscillator signal to generate a Q component of the received radio signal; where the I and Q components of the received signal have a receive bandwidth; computing an estimate of second order distortion components as a power output of the I and Q components between approximately the receive bandwidth and twice the receive bandwidth of the received radio signals; and adjusting an operational parameter of the radio receiver to reduce the estimated value of second order distortion components. This abstract is not to be considered limiting.