Wi-Fi radar detection using synchronized wireless access point

A Wireless Local-Area Network (WLAN) access point, comprising:

• a WLAN transmitter, configured to transmit WLAN packets via one or more transmit antennas, and to send a timing-synchronization signal over an internal interface;
• a WLAN receiver, configured to receive, via one or more receive antennas, echo packets comprising reflections from an object of a selected subset of the WLAN packets transmitted by the WLAN transmitter, to receive the timing-synchronization signal from the WLAN transmitter over the internal interface, and to time-synchronize the echo packets and the corresponding WLAN packets using the timing-synchronization signal;
• and
• a processor, configured to estimate one or more parameters of the object based on the time-synchronized echo packets and WLAN packets, including estimating a distance between the access point and the object by:
• for a given WLAN packet transmitted by the WLAN transmitter, identifying (i) an echo packet received from the target in response to the given WLAN packet, and (ii) a direct leakage of the given WLAN packet from the WLAN transmitter to the WLAN receiver;
• measuring a time delay between the echo packet and the direct leakage;
• and
• estimating the distance based on the time delay, and to output the estimated parameters to a user.

A method for communication in a Wireless Local-Area Network (WLAN) access point, the method comprising:

• in a WLAN transmitter of the access point, transmitting WLAN packets, comprises both communication packets and channel-sounding packets, via one or more transmit antennas, and sending a timing-synchronization signal over an internal interface;
• in a WLAN receiver of the access point, receiving echo packets comprising reflections from an object of a selected subset of the WLAN packets transmitted by the WLAN transmitter and the timing-synchronization signal, and time-synchronizing the echo packets and the corresponding WLAN packets using the timing-synchronization signal;
• and
• estimating one or more parameters of the object based on the channel-sounding packets and on the time-synchronized echo packets corresponding to the channel-sounding packets, and outputting the estimated parameters to a user.