Radar Detection Method And System Using Low-Resolution FFTS

A method of identifying radar in a wireless device, the method comprising:

• receiving a signal in the wireless device;
• detecting an event corresponding to receipt of the signal, the event including at least one of an analog to digital converter (ADC) saturation, a radio frequency (RF) saturation, an ADC power high condition, and an ADC power low condition;
• delaying gain change in the wireless device for a first predetermined time period;
• buffering data preceding the event for the first predetermined time period;
• performing a first short fast Fourier transform (FFT) with the buffered data;
• processing the first short FFT;
• determining whether results of the processing indicate the signal is radar;
• and
• when the signal is radar, identifying a type of the radar.

A method of processing a short fast Fourier transform (FFT) for radar detection, the method comprising:

• performing the short FFT on a received signal;
• finding a power and index of a strongest bin using results of the short FFT;
• calculating an in-band power and an out-of-band power using the results of the short FFT;
• determining whether the out-of-band power divided by the in-band power is greater than an FFT in-band threshold;
• when the out-of-band power divided by the in-band power is greater than the FFT in-band threshold, then identifying an out-of-band signal;
• when the out-of-band power divided by the in-band power is not greater than an FFT in-band threshold, then computing a high bin magnitude threshold;
• for each band, count a number of bins with power greater than the high bin magnitude threshold;
• when the number of bins is greater than a narrowband adjacent threshold for any band, then identifying a wideband signal;
• when the number of bins is not greater than the narrowband adjacent threshold for any band, then determining whether the number of bins is greater than a narrowband tone threshold for any band;
• and
• when the number of bins is greater than the narrowband tone threshold for any band, then identifying a narrowband signal, which is a possible radar, and its index.

A radar detect architecture implemented in hardware, the radar detect architecture comprising:

• after detecting one of an ADC (analog to digital converter) saturation, a RF (radio frequency) saturation, and an ADC power high based on a signal, delaying a gain change by a predetermined period and buffering data of the signal during the predetermined period;
• running a first short FFT with the buffered data;
• processing the first short FFT;
• and
• based on the processing, determining whether the signal is an in-band and narrowband signal.