Automatic RF transmit power control for over the air testing

1. A computer-implemented method for setting RF transmit power of a wireless device, the computer-implemented method comprising:

obtaining, by a computing system comprising one or more computing devices, power response data for a power detector of the wireless device, the power response data providing a relationship between power detector readings from the power detector and measured transmit power of a transmitter of the wireless device;

identifying, by the computing system, a target power detector reading value corresponding to a target transmit power based at least in part on the power response data by:

accessing, by the computing system, the power response data to determine a target power detector reading associated with the target transmit power in a first channel;

obtaining, by the computing system, a channel correction factor based at least in part on a characterization of power detector reading with respect to frequency; and

applying, by the computing system, the channel correction factor to the target power detector reading to correct the target power detector reading to a second channel, the second channel being different from the first channel;

initializing, by the computing system, a transmitter gain of the transmitter to an initial transmitter gain value;

obtaining, by the computing system, a power detector reading value from the power detector;

determining, by the computing system, that a difference between the power detector reading value and the target power detector reading value is greater than a tolerance margin; and

adjusting, by the computing system, a transmitter gain value of the transmitter in a direction of the difference between the power detector reading value and the target power detector reading value.

2. The computer-implemented method of claim 1 , the method further comprising:

determining, by the computing system, that the difference between the power detector reading value and the target power detector reading value is less than the tolerance margin; and

configuring the wireless device for wireless communications based on the transmitter gain value.

3. The computer-implemented method of claim 1 , the power response data comprising a power response lookup table, the power response lookup table correlating reference transmit power values to reference power detector reading values.

4. The computer-implemented method of claim 3 , the power response lookup table comprising a first column comprising the reference transmit power values and a second column comprising the reference power detector reading values.

5. The computer-implemented method of claim 3 , the power response lookup table comprising 16 entries corresponding to an upper quarter of a dynamic range of the transmitter.

6. The computer-implemented method of claim 1 , the power detector comprising an analog-to-digital converter coupled to a transmit path of the transmitter.

7. The computer-implemented method of claim 1 , a band over which the transmitter being configured to communicate comprises a low channel, a middle channel, and a high channel, the first channel comprising a reference frequency, and the second channel comprising one of the low channel, the middle channel, or the high channel.

8. The computer-implemented method of claim 1 , adjusting the transmitter gain value comprising one of incrementally increasing or incrementally decreasing the transmitter gain value.

9. The computer-implemented method of claim 1 , the power response data being established during an RF calibration stage.

10. The computer-implemented method of claim 1 , the device being placed into a factory test mode such that the transmitter gain of the device can be controlled.

11. The computer-implemented method of claim 1 , the initial transmitter gain value being an average gain value established based at least in part on over-the-air testing of a plurality of other wireless devices.

12. The computer-implemented method of claim 1 , the wireless device comprising a wearable device.

13. The computer-implemented method of claim 1 , the transmitter comprising an LTE transmitter.

14. The computer-implemented method of claim 1 , the transmitter gain value comprising a transmitter automatic gain control (Tx AGC) value.

15. A wearable device, comprising:

a transmitter comprising a power detector;

one or more processors; and

one or more nonvolatile memory devices storing computer-readable instructions, that, when implemented, cause the one or more processors to perform operations, the operations comprising:

obtaining power response data for the power detector, the power response data providing a relationship between power detector readings from the power detector and measured transmit power of the transmitter;

identifying a target power detector reading value corresponding to a target transmit power based at least in part on the power response data by:

accessing the power response data to determine a target power detector reading associated with the target transmit power in a first channel;

obtaining a channel correction factor based at least in part on a characterization of power detector reading with respect to frequency; and

applying the channel correction factor to the target power detector reading to correct the target power detector reading to a second channel, the second channel being different from the first channel;

initializing a transmitter gain of the transmitter to an initial transmitter gain value;

obtaining a power detector reading value from the power detector;

determining, by the computing system, that a difference between the power detector reading value and the target power detector reading value is greater than a tolerance margin; and

adjusting a transmitter gain value of the transmitter in a direction of the difference between the power detector reading value and the target power detector reading value.

16. The wearable device of claim 15 , the operations further comprising:

determining that the difference between the power detector reading value and the target power detector reading value is less than the tolerance margin; and

configuring the wireless device for wireless communications based on the transmitter gain value.

17. The wearable device of claim 15 , the power response data comprising a power response lookup table, the power response lookup table correlating reference transmit power values to reference power detector reading values.

18. The wearable device of claim 15 , the power response data being established during an RF calibration stage.