Specific Absorption Rate Mitigation

Abstract

Specific Absorption Rate (SAR) mitigation techniques are described herein. In one or more embodiments, a host device is configured to implement a SAR mitigation algorithm to maintain compliance with regulatory requirements. The SAR mitigation algorithm may be configured to control radio frequency transmissions (e.g., output levels) for one or more antennas of the host device based at least in part upon an arrangement of an accessory device relative to the host device. By so doing, the SAR mitigation algorithm accounts for adverse influences that accessory devices may have upon radio frequency (RF) emissions from the antennas in some arrangements. The SAR mitigation algorithm may be further configured to account for user presence indications along with accessory device arrangements and adapt transmission power levels accordingly.

What is claimed is: 
     
         1 . A method comprising:
 detecting an arrangement of an accessory device relative to a host computing device to which the accessory device is physically connectable; and   setting transmission power levels for one or more antennas of the host computing device in dependence upon the detected arrangement of the accessory device.   
     
     
         2 . A method as described in  claim 1 , wherein setting the transmission power levels comprises reducing a transmission power level of at least one of said antennas in dependence upon the detected arrangement to maintain compliance with a legal limit established for specific absorption rate (SAR). 
     
     
         3 . A method as described in  claim 1 , wherein setting the transmission power levels comprises enforcing a maximum transmission power level for each of the one or more antennas established with respect to the detected arrangement of the accessory device. 
     
     
         4 . A method as described in  claim 1 , setting the transmission power levels comprises:
 obtaining accessory identification data indicative of an identity of the accessory device;   looking-up antenna operational parameters for the one or more antennas based upon the detected arrangement and the identity of the accessory device; and   setting the transmission power levels in accordance with the antenna operational parameters.   
     
     
         5 . A method as described in  claim 1 , wherein the accessory device is removably connectable communicatively and physically to the host computing device via an interface. 
     
     
         6 . A method as described in  claim 5 , wherein the interface in configured to enable manipulation of the accessory device relative to the host computing device into multiple different arrangements, the multiple different arrangements each associated with respective operational parameters for the one or more antennas. 
     
     
         7 . A method as described in  claim 1 , wherein detecting the arrangement comprises recognizing the arrangement from multiple possible arrangements via one or more accessory detectors provided with the host computing device. 
     
     
         8 . A method as described in  claim 7 , wherein the accessory detectors comprise one or more of a capacitive sensor, a pressure sensor, a gyroscope, an accelerometer, an optical detector, or a magnetic field detector. 
     
     
         9 . A method as described in  claim 1 , wherein the one or more antennas include at least a pair of cellular antennas for cellular communications. 
     
     
         10 . A computing device comprising:
 one or more antennas configured to provide wireless communication functionality;   one or more hardware elements configured to implement a specific absorption rate manager module operable to:
 obtain accessory identification data indicative of an identity of an accessory device communicatively and physically coupled to the host computing device via the interface; 
 detect an arrangement of the accessory device relative to the host computing device; 
 identify antenna control actions indicated for the one or more antennas with respect to the detected arrangement and the identity of the accessory device; and 
 control operations of the one or more antennas in accordance with the identified antenna control actions. 
   
     
     
         11 . The computing device as described in  claim 10 , wherein the antenna control actions comprise one or more of setting transmission power limits, throttling of one or more antennas, prioritization of antenna communications, power back-off adjustments, intentional radio degradation, or radiation pattern modifications. 
     
     
         12 . The computing device as described in  claim 10 , wherein control of the operations includes applying control actions to mitigate potential for exceeding legal specific absorption rate (SAR) limits be applied for antennas that contribute to SAR emissions in relation to the detected arrangement. 
     
     
         13 . The computing device described in  claim 10 , wherein control of the operations includes applying control actions to boost or maintain performance for antennas that do not significantly contribute to SAR emissions in relation to the detected arrangement. 
     
     
         14 . The computing device described in  claim 10 , wherein identification of the antenna control actions comprises referencing a mapping data structure to look-up control actions associated with the one or more antennas in relation to the detected arrangement and the identity of the accessory device, the mapping data structure configured to associate antenna operational parameters and corresponding control actions with accessory device arrangements for multiple different accessory devices connectable to the host computing device at different times via the interface. 
     
     
         15 . The computing device described in  claim 10 , wherein the antennas include at least a pair of cellular antennas to provide cellular communications, a pair of Wi-Fi antennas for Wi-Fi communications, and a global navigation satellite system (GNSS) antenna to provide global navigation. 
     
     
         16 . A host computing device comprising:
 a processing system;   an interface to communicatively and physically couple different accessory devices to the host computing device;   multiple antennas to provide wireless communication functionality;   one or more computer readable media comprising instructions that, when executed via the processing system, implement a specific absorption rate (SAR) mitigation algorithm configured to perform operations to control operations of the multiple antennas comprising:
 obtaining accessory identification data indicative of an identity of an accessory device communicatively and physically coupled to the host computing device via the interface; 
 detecting an arrangement of the accessory device relative to the host computing device; 
 identifying antenna control actions indicated for the one or more antennas with respect to the detected arrangement and the identity of the accessory device; and 
 controlling operations of the one or more antennas in accordance with the identified antenna control actions. 
   
     
     
         17 . The host computing device as recited in  claim 16 , wherein the antenna control actions comprise one or more of setting transmission power limits, throttling of one or more antennas, prioritization of antenna communications, power back-off adjustments, intentional radio degradation, or radiation pattern modifications. 
     
     
         18 . The host computing device as recited in  claim 16 , wherein controlling operations of the one or more antennas in accordance with the identified antenna control actions comprises:
 applying control actions to mitigate potential for exceeding legal specific absorption rate (SAR) limits be applied for antennas that contribute to SAR emissions in relation to the detected arrangement; and   applying control actions to boost or maintain performance for antennas that do not significantly contribute to SAR emissions in relation to the detected arrangement.   
     
     
         19 . A host computing device recited in  claim 16 , wherein identifying the antenna control actions comprises referencing a mapping data structure to look-up control actions associated with the one or more antennas in relation to the detected arrangement and the identity of the accessory device, the mapping data structure configured to associate antenna operational parameters and corresponding control actions with accessory device arrangements for multiple different accessory devices connectable to the host computing device at different times via the interface. 
     
     
         20 . The host computing device as recited in  claim 16 , wherein the antennas include at least a pair of cellular antennas to provide cellular communications, a pair of Wi-Fi antennas for Wi-Fi communications, and a global navigation satellite system (GNSS) antenna to provide global navigation.