System and method for vehicle occupancy detection

1 . A system for detecting one or more occupants in a vehicle, the system comprising:

a plurality of wireless modules, wherein one or more of the plurality of wireless modules is at least one of: a digital wireless local area network (WLAN) transceiver system configured to implement a wireless communication protocol and a signal conversion device configured to convert signals between at least two frequency bands, wherein one or more of the plurality of wireless modules are located within a passenger compartment of the vehicle, and wherein a location of each of the plurality of wireless modules is determined based at least in part on an estimated sensing signal-to-noise ratio (SSNR) at one or more target locations within the passenger compartment of the vehicle;

a controller in electrical communication with the plurality of wireless modules, wherein the controller is programmed to:

perform one or more sensing rounds, wherein each of the one or more sensing rounds includes communication between at least two of the plurality of wireless modules; and

determine a presence of the one or more occupants in the vehicle based at least in part on the one or more sensing rounds.

2 . The system of claim 1 , wherein to perform the one or more sensing rounds, the controller is further programmed to:

determine a plurality of participating wireless modules, wherein the plurality of participating wireless modules is a subset of the plurality of wireless modules, and wherein the plurality of participating wireless modules includes at least two of the plurality of wireless modules;

transmit one or more signals between at least two of the plurality of participating wireless modules; and

determine a plurality of channel state information (CSI) values based at least in part on the one or more signals.

3 . The system of claim 2 , wherein to determine the plurality of participating wireless modules, the controller is further programmed to:

determine a predicted location of the one or more occupants within the passenger compartment of the vehicle; and

determine the plurality of participating wireless modules based at least in part on the predicted location of the one or more occupants within the passenger compartment of the vehicle.

4 . The system of claim 3 , further comprising one or more vehicle sensors in electrical communication with the controller, wherein to determine the predicted location of the one or more occupants within the passenger compartment of the vehicle, the controller is further programmed to:

perform one or more measurements using the one or more vehicle sensors; and

determine the predicted location of the one or more occupants within the passenger compartment of the vehicle based at least in part on the one or more measurements.

5 . The system of claim 2 , wherein to transmit the one or more signals between the at least two of the plurality of participating wireless modules, the controller is further programmed to:

transmit the one or more signals between each combination of two of the plurality of participating wireless modules.

6 . The system of claim 2 , wherein to transmit the one or more signals between the at least two of the plurality of participating wireless modules, the controller is further programmed to:

vary a frequency band of the one or more signals between at least two of the one or more sensing rounds.

7 . The system of claim 2 , wherein to determine the presence of the one or more occupants in the vehicle, the controller is further programmed to:

perform an inverse Fourier transform on the plurality of CSI values to determine a time-domain power delay profile;

identify a motion marker based at least in part on the time-domain power delay profile; and

determine a presence of the one or more occupants in the vehicle based at least in part on the motion marker.

8 . The system of claim 1 , wherein the SSNR at a target location within the passenger compartment of the vehicle is defined by:

S

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S

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N

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R

T

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γ

1

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2

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γ

1

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T

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γ

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wherein SSNR T is the SSNR at the target location within the passenger compartment of the vehicle, γ 12 is a distance between a first of the plurality of wireless modules and a second of the plurality of wireless modules, γ 1T is a distance between the first of the plurality of wireless modules and the target location, and is a distance between the second of the plurality of wireless modules and the target location.

9 . A method for detecting one or more occupants in a vehicle, the method comprising:

performing one or more sensing rounds, wherein each of the one or more sensing rounds includes communication between at least two of a plurality of wireless modules, wherein performing the one or more sensing rounds further comprises:

determining a plurality of participating wireless modules, wherein the plurality of participating wireless modules is a subset of the plurality of wireless modules, and wherein the plurality of participating wireless modules includes at least two of the plurality of wireless modules;

transmitting one or more signals between at least two of the plurality of participating wireless modules;

determining a plurality of channel state information (CSI) values based at least in part on the one or more signals; and

determining a presence of the one or more occupants in the vehicle based at least in part on the one or more sensing rounds.

10 . The method of claim 9 , wherein determining the plurality of participating wireless modules further comprises:

determining a predicted location of the one or more occupants within a passenger compartment of the vehicle; and

determining the plurality of participating wireless modules based at least in part on the predicted location of the one or more occupants within the passenger compartment of the vehicle.

11 . The method of claim 10 , wherein determining the predicted location of the one or more occupants within the passenger compartment of the vehicle further comprises:

performing one or more measurements using one or more vehicle sensors, wherein the one or more vehicle sensors includes at least one of: a vehicle camera, a vehicle microphone, and a vehicle seat occupancy sensor; and

determining the predicted location of the one or more occupants within the passenger compartment of the vehicle based at least in part on the one or more measurements.

12 . The method of claim 11 , wherein transmitting the one or more signals between at least two of the plurality of participating wireless modules further comprises:

transmitting the one or more signals between each combination of two of the plurality of participating wireless modules.

13 . The method of claim 11 , wherein transmitting the one or more signals between at least two of the plurality of participating wireless modules further comprises:

varying a frequency band of the one or more signals between at least two of the one or more sensing rounds.

14 . The method of claim 11 , wherein determining the presence of the one or more occupants in the vehicle further comprises:

performing an inverse Fourier transform on the plurality of CSI values to determine a time-domain power delay profile;

identifying a motion marker based at least in part on the time-domain power delay profile; and

determining the presence of the one or more occupants in the vehicle based at least in part on the motion marker.

15 . A system for detecting one or more occupants in a vehicle, the system comprising:

a plurality of wireless modules;

one or more vehicle sensors, wherein the one or more vehicle sensors includes at least one of: a vehicle camera, a vehicle microphone, and a vehicle seat occupancy sensor; and

a controller in electrical communication with the plurality of wireless modules and the one or more vehicle sensors, wherein the controller is programmed to:

perform one or more measurements using the one or more vehicle sensors;

determine a predicted location of the one or more occupants within a passenger compartment of the vehicle based at least in part on the one or more measurements;

determine a plurality of participating wireless modules based at least in part on the predicted location of the one or more occupants within the passenger compartment of the vehicle, wherein the plurality of participating wireless modules is a subset of the plurality of wireless modules, and wherein the plurality of participating wireless modules includes at least two of the plurality of wireless modules;

transmit one or more signals between at least two of the plurality of participating wireless modules;

determine a plurality of channel state information (CSI) values based at least in part on the one or more signals; and

determine a presence of the one or more occupants in the vehicle based at least in part on the plurality of CSI values.

16 . The system of claim 15 , wherein to determine the presence of the one or more occupants in the vehicle, the controller is further programmed to:

perform an inverse Fourier transform on the plurality of CSI values to determine a time-domain power delay profile, wherein the time-domain power delay profile includes one or more reflections of the one or more signals;

identify a motion marker based at least in part on the one or more reflections in the time-domain power delay profile; and

determine the presence of the one or more occupants in the vehicle based at least in part on the motion marker.

17 . The system of claim 16 , wherein one or more of the plurality of wireless modules are located within a passenger compartment of the vehicle, and wherein a location of each of the plurality of wireless modules is determined based at least in part on an estimated sensing signal-to-noise ratio (SSNR) at one or more target locations within the passenger compartment of the vehicle.