Electronic devices with time domain radio-frequency exposure averaging
An electronic device may include a radio that generates a first maximum power based on a radio-frequency exposure (RFE) budget. The radio may transmit signals subject to the first maximum power during a subperiod of an averaging period and may generate an instantaneous RFE metric value based on an antenna coefficient and the conducted transmit power of the antenna during the subperiod. The radio may generate a consumed RFE value by averaging the instantaneous RFE metric value with previous instantaneous RFE values from the averaging period, may generate a remaining budget based on the consumed RFE value, may generate a second maximum transmit power based on the remaining budget, and may transmit signals during a subsequent subperiod subject to the second maximum power. Time-averaging the RFE metric may serve to optimize performance of the radio relative to scenarios where the radio performs time-averaging of conducted TX power.
1. A method of operating an electronic device subject to a regulatory limit on transmitted power over an averaging period, the regulatory limit having a first level when an external object is located at a first position relative to the electronic device and a second level that is lower than the first level when the external object is located at a second position relative to the electronic device, the method comprising:
with one or more antennas, transmitting radio-frequency signals at a first transmit power level that is less than the first level during a first portion of the averaging period when the external object is at the first position relative to the electronic device; and
with the one or more antennas, transmitting radio-frequency signals at a second transmit power level that exceeds the second level during a second portion of the averaging period when the external object is at the second position relative to the electronic device.
2. The method of claim 1 , wherein the second position is closer to the electronic device than the first position.
3. The method of claim 1 , wherein the radio-frequency signals are at a frequency greater than 6 GHz.
4. The method of claim 1 , wherein the radio-frequency signals are at a frequency less than 6 GHz.
5. The method of claim 1 , wherein the second portion of the averaging period is after the first portion of the averaging period.
6. The method of claim 1 , wherein the first transmit power level is at or below a first maximum transmit power level that is based on an antenna coefficient of the one or more antennas.
7. The method of claim 6 , wherein the first maximum transmit power level is based on a radio-frequency exposure (RFE) budget.
8. The method of claim 7 , wherein the second transmit power level is at or below a second maximum transmit power level that is based on an instantaneous RFE metric value associated with the one or more antennas during the first portion of the averaging period and a consumed RFE metric value associated with the one or more antennas.
9. An electronic device subject to a regulatory limit on transmitted power over an averaging period, the regulatory limit having a first level when an external object is located at a first position relative to the electronic device and a second level that is lower than the first level when the external object is located at a second position relative to the electronic device, the electronic device comprising:
a radio; and
one or more antennas coupled to the radio, wherein the radio is configured to use the one or more antennas to
transmit radio-frequency signals at a first transmit power level that is less than the first level during a first portion of the averaging period when the external object is at the first position relative to the electronic device; and
transmit radio-frequency signals at a second transmit power level that exceeds the second level during a second portion of the averaging period when the external object is at the second position relative to the electronic device.
10. The electronic device of claim 9 , further comprising:
a sensor configured to measure whether the external object is at the first position or the second position relative to the electronic device.
11. The electronic device of claim 10 , wherein the sensor comprises a radio-frequency sensor coupled to the one or more antennas.
12. The electronic device of claim 9 , wherein the radio-frequency signals are at a frequency greater than 6 GHz.
13. The electronic device of claim 9 , wherein the radio-frequency signals are at a frequency less than 6 GHz.
14. The electronic device of claim 9 , wherein the second portion of the averaging period is after the first portion of the averaging period.
15. The electronic device of claim 9 , wherein the first transmit power level is at or below a first maximum transmit power level that is based on an antenna coefficient of the one or more antennas.
16. The electronic device of claim 15 , wherein the first maximum transmit power level is based on a radio-frequency exposure (RFE) budget.
17. The electronic device of claim 16 , wherein the second transmit power level is at or below a second maximum transmit power level that is based on an instantaneous RFE metric value associated with the one or more antennas during the first portion of the averaging period and a consumed RFE metric value associated with the one or more antennas.
18. An electronic device comprising:
one or more antennas; and
a radio communicably coupled to the one or more antennas, the radio being configured to
transmit first radio-frequency signals using the one or more antennas during a first subperiod of an averaging period while subject to a first maximum transmit power level that is based on a radio-frequency exposure (RFE) budget assigned to the radio and an antenna coefficient associated with the one or more antennas antenna, and
transmit second radio-frequency signals using the one or more antennas during a second subperiod of the averaging period subsequent to the first subperiod while subject to a second maximum transmit power level that is based on a remaining RFE budget and the antenna coefficient.
19. The electronic device of claim 18 , wherein the remaining RFE budget comprises a remaining RFE budget for the averaging period that is based on a consumed RFE metric value and the RFE budget.
20. The electronic device of claim 19 , wherein the consumed RFE metric value is based on an instantaneous RFE metric value that is based on a conducted transmit power of the one or more antennas during the first subperiod.