| 摘要 |
Communicating between stations over a shared medium comprises: transmitting a waveform from a first station over the shared medium at a time that is based on a shared time reference shared by multiple of the stations, the waveform including at least a first symbol, having a predetermined symbol length, comprising a first set of frequency components at predetermined carrier frequencies modulated with preamble information stored in a second station and a second set of frequency components at predetermined carrier frequencies modulated with information to be communicated to at least one station, with the carrier frequencies of the first and second sets of frequency components being integral multiples of a frequency interval determined by the inverse of the symbol length; monitoring the shared medium at a second station, before transmission of the waveform from the first station, to detect a start of the first symbol of the waveform at one of multiple time slot boundaries, the monitoring including, after each of multiple time slot boundaries, periodically sampling a series of values received over the shared medium starting at the beginning of the most recent time slot boundary and processing the sampled values to generate a metric value that indicates whether the start of the first symbol of the waveform has been detected; and in response to detecting the start of the first symbol of the waveform, demodulating the first symbol of the waveform from values sampled based on the shared time reference.
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