Communications device and related method that detects radio frequency (RF) interferer on a communications channel

A communications device, comprising:

• a transceiver configured to transmit and receive communications signals over a communications channel and comprising:
• a demodulator configured to demodulate a received communications signal into complex time domain samples;
• a processor coupled to the demodulator and having a buffer and configured to:
• normalize all complex time domain samples within the buffer to fractional amplitude values,
• determine the variance over time domain magnitude samples based on a computed mean over all normalized time domain samples,
• perform a complex Fast Fourier Transform (CFFT) on all complex time domain samples as magnitude and phase to obtain frequency domain samples, and
• determine the variance over the frequency domain samples based on a computed mean over all frequency domain magnitude samples;
• and
• a comparator configured to compare a variance ratio of the variance in the time domain magnitude samples and the variance in the frequency domain samples with a threshold to determine if a radio frequency (RF) interferer is present, indicative that the communications channel is busy, wherein in response to the indication that the communications channel is busy, the transceiver will not transmit a communications signal over the communications channel.

A method of detecting a radio frequency (RF) interferer signal on a communications channel, comprising:

• receiving a communications signal within a receiver;
• demodulating the communications signal within a demodulator and obtaining a plurality of complex time domain samples;
• normalizing all complex time domain samples within a buffer to fractional amplitude values;
• determining the variance over time domain magnitude samples based on a computed mean over all normalized time domain samples;
• performing a complex Fast Fourier Transform (CFFT) on all complex time domain samples as magnitude and phase to obtain frequency domain samples;
• determining the variance over the frequency domain samples based on a computed mean over all frequency domain magnitude samples;
• and
• comparing a variance ratio of the variance in the time domain magnitude samples and the variance in the frequency domain samples with a threshold to determine if a RF interferer is present, indicative that the communications channel is busy.