SR Technologies, Inc.

A method for detecting a preamble waveform of a received signal is described. The method includes dividing a correlation into a plurality of sub-correlations, for a plurality of frequency offset indices, k, covering a range of frequency offsets. The correlation has a correlation length equal to N, and a plurality of sub-correlations has a sub-correlations quantity equal to I, each sub-correlation of the plurality of sub-correlations has a sub-correlation length equal to M. A complex oscillation for a template frequency offset associated with k is approximated, the approximation is to be constant over an M-sample interval and is a piece-wise approximation. The approximated complex oscillation has length I. A quantity I of sub-correlations at each k is assembled using the approximated complex oscillation of length I. The method further includes determining that the received signal comprises the preamble based on the assembled sub-correlations and a correlation threshold.

A method for detecting a preamble waveform of a received signal is described. The method includes dividing a correlation into a plurality of sub-correlations, for a plurality of frequency offset indices, k, covering a range of frequency offsets. The correlation has a correlation length equal to N, and a plurality of sub-correlations has a sub-correlations quantity equal to I, each sub-correlation of the plurality of sub-correlations has a sub-correlation length equal to M. A complex oscillation for a template frequency offset associated with k is approximated, the approximation is to be constant over an M-sample interval and is a piece-wise approximation. The approximated complex oscillation has length I. A quantity I of sub-correlations at each k is assembled using the approximated complex oscillation of length I. The method further includes determining that the received signal comprises the preamble based on the assembled sub-correlations and a correlation threshold.

A method in a monitoring station configured for communication with a wireless device is described. The method includes determining a round trip time, RTT, that corresponds to a first packet transmitted to the wireless device; receiving a second packet from the wireless device; determining the second packet from the wireless device has been received without error based at least in part on an error-detecting field; and receiving a subsequent packet from the wireless device. The method further includes determining that the subsequent packet received is a second packet retransmission; determining a preamble receipt time of the subsequent packet; determining a delay value based in part on the RTT of the first packet, the length field of the subsequent packet, and data rate field of the subsequent packet. The first acknowledgement packet is transmitted timed at the delay value after the preamble receipt time of the subsequent packet.

A method and waveform handling apparatus for capturing and storing data waveforms and metadata for analysis. The method includes receiving waveform data and metadata, the waveform data corresponding to a demodulated data burst, creating a waveform data record from the received waveform data, associating the waveform data with corresponding metadata, and creating a metadata record from the corresponding metadata. The method allows the waveform data in the waveform data record to be stored in a first data repository and the corresponding metadata in the metadata record to be stored in a second data repository, the waveform data and the corresponding metadata accessible for analysis.