Reducing impact of clock drift in wireless devices

Abstract

Described are systems and methods for obtaining synchronization at a clock maintained at a wireless device having a respective clock drift. The wireless device may obtain one or more messages indicating two or more clock errors corresponding to two more access points. The wireless device may then establish communication with an access point corresponding to the smallest clock error of the two or more clock errors by synchronizing the clock maintained at the wireless device based on the smallest clock error.

What is claimed is: 
     
         1 . A first wireless device, the first wireless device comprising:
 a receiver to receive frames from the communication network; and   a processor configured to:   obtain two or more clock errors received at the receiver corresponding to two or more access points, wherein the two or more clock errors are broadcasted by the corresponding two or more access points;   determine a smallest clock error of the two or more clock errors; and   establish communication with an access point corresponding to the smallest clock error, by synchronizing a clock of the wireless device based on the smallest clock error.   
     
     
         2 . The first wireless device of  claim 1 , wherein the two or more clock errors are obtained in a fine timing measurement request exchange between the first wireless device and the two or more access points. 
     
     
         3 . The first wireless device of  claim 1 , wherein the two or more clock errors comprise maximum clock errors of the two or more access points. 
     
     
         4 . The first wireless device of  claim 1 , wherein the access point corresponding to the smallest clock error is configured to establish itself as a master access point of the two or more access points. 
     
     
         5 . The first wireless device of  claim 1 , wherein the two or more clock errors are broadcasted in one or more beacons. 
     
     
         6 . The first wireless device of  claim 1 , wherein the processor is further configured to:
 compute a round-trip time of a message exchange with a second wireless device based, at least in part, on the synchronized clock of the first wireless device.   
     
     
         7 . The first wireless device of  claim 1 , wherein the two or more clock errors are expressed as parts per million (ppm). 
     
     
         8 . A first wireless device, the first wireless device comprising:
 means for receiving two or more clock errors corresponding to two or more access points, wherein the two or more clock errors are broadcasted by the two or more access points;   means for determining a smallest clock error of the two or more clock errors; and   means for establishing communication with an access point corresponding to the smallest clock error, by synchronizing a clock of the first wireless device based on the smallest clock error.   
     
     
         9 . The first wireless device of  claim 8 , wherein the two or more clock errors are obtained in a fine timing measurement request exchange between the first wireless device and the two or more access points. 
     
     
         10 . The first wireless device of  claim 8 , wherein the two or more clock errors comprise maximum clock errors of the two or more access points. 
     
     
         11 . The first wireless device of  claim 8 , wherein the access point corresponding to the smallest clock error is configured to establish itself as a master access point of the two or more access points. 
     
     
         12 . The first wireless device of  claim 8 , wherein the two or more clock errors are broadcasted in one or more beacons. 
     
     
         13 . The first wireless device of  claim 8 , wherein the processor is further configured to:
 compute a round-trip time of a message exchange with a second wireless device based, at least in part, on the synchronized clock of the first wireless device.   
     
     
         14 . The first wireless device of  claim 8 , wherein the two or more clock errors are expressed as parts per million (ppm). 
     
     
         15 . A non-transitory computer-readable storage medium comprising program instructions, which are executable by a processor of a first wireless device to direct the first wireless device to:
 obtain two or more clock errors corresponding to two or more access points, wherein the two or more clock errors are broadcasted by the two or more access points;   determine a smallest clock error of the two or more clock errors; and   establish communication with an access point corresponding to the smallest clock error, by synchronizing a clock of the first wireless device based on the smallest clock error.   
     
     
         16 . The non-transitory computer-readable storage medium of  claim 15 , wherein the two or more clock errors are obtained in a fine timing measurement request exchange between the first wireless device and the two or more access points. 
     
     
         17 . The non-transitory computer-readable storage medium of  15 , wherein the two or more clock errors comprise maximum clock errors of the two or more access points. 
     
     
         18 . The non-transitory computer-readable storage medium of  claim 15 , wherein the access point corresponding to the smallest clock error is configured to establish itself as a master access point of the two or more access points. 
     
     
         19 . The non-transitory computer-readable storage medium of  claim 15 , wherein the two or more clock errors are broadcasted in one or more beacons. 
     
     
         20 . The non-transitory computer-readable storage medium of  claim 15 , wherein the program instructions are implementable by the processor to further direct the first wireless device to:
 compute a round-trip time of a message exchange with a second wireless device based, at least in part, on the synchronized clock of the first wireless device.