Storing modem parameters for motion detection

1. A motion detection method comprising:

accessing stored modem parameters from a memory of a wireless sensor device, the stored modem parameters representing a radio state previously used by a radio subsystem of the wireless sensor device in processing a first motion detection signal;

applying the stored modem parameters to the radio subsystem of the wireless sensor device;

processing a second motion detection signal at the wireless sensor device using the radio state represented by the stored modem parameters; and

by operation of one or more processors, detecting motion based on the first and second motion detection signals.

2. The method of claim 1 , wherein the modem parameters include one or more of a gain setting, an RF filter setting, an RF front end switch setting, a DC offset setting, or an IQ compensation setting.

3. The method of claim 1 , wherein applying the stored modem parameters to the radio subsystem of the wireless sensor device comprises holding one or more modem parameters of the radio subsystem constant.

4. The method of claim 1 , wherein the modem parameters further represent a baseband processing state previously used by a baseband subsystem of the wireless sensor device in processing the first motion detection signal, and the method comprises applying the stored modem parameters to the baseband subsystem of the wireless sensor device.

5. The method of claim 4 , wherein the modem parameters include one or more of a digital DC correction setting, a digital gain setting, or a digital filtering setting.

6. The method of claim 1 , comprising storing the modem parameters in response to receiving the first motion detection signal at the wireless sensor device.

7. The method of claim 6 , wherein the first motion detection signal comprises a packet comprising a header and a payload, and the method comprises reading the header to determine that the first motion detection signal has been received at the wireless sensor device.

8. The method of claim 1 , wherein the stored modem parameters are first modem parameters representing a first radio state, and the method comprises:

applying second modem parameters to the radio subsystem of the wireless sensor device, the second modem parameters representing a second, different radio state;

processing additional motion detection signals at the wireless sensor device using the second radio state parameters; and

detecting motion based on the additional motion detection signals and independent of the first and second motion detection signals.

9. The method of claim 1 , wherein the first and second motion detection signals are based on wireless signals transmitted from a wireless transmitter device to the wireless sensor device, and detecting motion comprises detecting motion of an object in a space accessed by the wireless signals between the wireless transmitter device and the wireless sensor device.

10. A wireless sensor device comprising:

a modem comprising a radio subsystem configured to process signals received by the wireless sensor device;

a memory configured to store modem parameters representing a radio state used by the radio subsystem in processing a first motion detection signal received by the wireless sensor device;

one or more processors configured to perform operations comprising:

accessing the modem parameters from the memory;

applying the modem parameters to the radio subsystem;

receiving a second motion detection signal processed by the radio subsystem using the radio state represented by the stored modem parameters; and

detecting motion based on the first and second motion detection signals.

11. The wireless sensor device of claim 10 , wherein the modem parameters include one or more of a gain setting, an RF filter setting, an RF front end switch setting, a DC offset setting, or an IQ compensation setting.

12. The wireless sensor device of claim 10 , wherein applying the modem parameters to the radio subsystem comprises holding one or more modem parameters constant.

13. The wireless sensor device of claim 10 , wherein the modem further comprises a baseband subsystem, the modem parameters further represent a baseband processing state used by the baseband subsystem in processing the first motion detection signal, and the operations comprise applying the modem parameters to the baseband subsystem.

14. The wireless sensor device of claim 13 , wherein the modem parameters include one or more of a digital DC correction setting, a digital gain setting, or a digital filtering setting.

15. The wireless sensor device of claim 10 , wherein the operations comprise storing the modem parameters in response to receiving the first motion detection signal at the wireless sensor device.

16. The wireless sensor device of claim 15 , wherein the first motion detection signal comprises a packet comprising a header and a payload, and the operations comprise reading the header to determine that the first motion detection signal has been received at the wireless sensor device.

17. The wireless sensor device of claim 10 , wherein the modem parameters are first modem parameters representing a first radio state, and the operations comprise:

applying second modem parameters to the radio subsystem, the second modem parameters representing a second, different radio state;

processing additional motion detection signals at the wireless sensor device using the second radio state parameters; and

detecting motion based on the additional motion detection signals and independent of the first and second motion detection signals.

18. The wireless sensor device of claim 10 , wherein detecting motion comprises detecting motion of an object in a space accessed by the first and second motion detection signals between a wireless transmitter to the wireless sensor device.

19. A non-transitory computer-readable medium storing instructions that are operable when executed by the data processing apparatus to perform operations comprising:

accessing stored modem parameters from a memory of a wireless sensor device, the stored modem parameters representing a radio state previously used by a radio subsystem of the wireless sensor device in processing a first motion detection signal;

applying the stored modem parameters to the radio subsystem of the wireless sensor device;

processing a second motion detection signal at the wireless sensor device using the radio state represented by the stored modem parameters; and

detecting motion based on the first and second motion detection signals.

20. The computer-readable medium of claim 19 , wherein the modem parameters further represent a baseband processing state previously used by a baseband subsystem of the wireless sensor device in processing the first motion detection signal, and the operations comprise applying the stored modem parameters to the baseband subsystem of the wireless sensor device.