Abstract: A method, apparatus, and system for using a user device to communicate with a touch-screen of an electronic device includes generating, by an electronic circuit of the user device, a signal by encoding a data sequence that may be stored in a memory of the user device and communicating the signal from the user device, to the electronic device by varying a capacitance of the touch-screen thereof. The electronic device receives the signal to obtain the data sequence. The electronic device may use the data sequence to at least authenticate a user of the user device.

Abstract: We consider a problem of radio frequency (RF) signal analysis where one sensing node observes a frequency band possibly used by multiple packet based radio transmitters. Analysis of the received signal includes two steps. In the first step we use a spectrogram to perform temporal segmentation of the received nonstationary signal. This task may be formulated as a clustering problem. In the second step we compute a certain 2-D slice of the fourth order spectrum for each of the segments found in the first step. These fourth order spectrum slices are arraigned in a three-way array. One aspect of the second step is to use uniqueness properties of the low rank decomposition of the three-way array to recover spectra and associated activity sequences of individual components in the received signal. We derive a numerical algorithm for the low rank decomposition, which computes estimates of the spectra and activity sequences by optimizing certain weighted least squares criterion under application specific constraints.

Abstract: We consider a problem of radio frequency (RF) signal analysis where one sensing node observes a frequency band possibly used by multiple packet based radio transmitters. Analysis of the received signal includes two steps. In the first step we use a spectrogram to perform temporal segmentation of the received nonstationary signal. This task may be formulated as a clustering problem. In the second step we compute a certain 2-D slice of the fourth order spectrum for each of the segments found in the first step. These fourth order spectrum slices are arraigned in a three-way array. One aspect of the second step is to use uniqueness properties of the low rank decomposition of the three-way array to recover spectra and associated activity sequences of individual components in the received signal. We derive a numerical algorithm for the low rank decomposition, which computes estimates of the spectra and activity sequences by optimizing certain weighted least squares criterion under application specific constraints.

Abstract: Doppler correction system and method comprising receiving a Doppler effected signal comprising a preamble signal (32). A delayed preamble signal (48) may be generated based on the preamble signal (32). The preamble signal (32) may be multiplied by the delayed preamble signal (48) to generate an in-phase preamble signal (60). The in-phase preamble signal (60) may be filtered to generate a substantially constant in-phase preamble signal (62). A plurality of samples of the substantially constant in-phase preamble signal (62) may be accumulated. A phase-shifted signal (76) may also be generated based on the preamble signal (32). The phase-shifted signal (76) may be multiplied by the delayed preamble signal (48) to generate an out-of-phase preamble signal (80). The out-of-phase preamble signal (80) may be filtered to generate a substantially constant out-of-phase preamble signal (82). A plurality of samples of the substantially constant out-of-phase signal (82) may be accumulated.