Reduced power synchronisation of wireless device

Synchronizing at least one wireless sensor includes sending at least one reference message along with a request for acquired data from an access point to the at least one wireless sensor, where the reference message includes a first timestamp indicating when the reference message was sent according to time of a clock of the access point, receiving from the at least one wireless sensor a response that includes the requested data, the first timestamp, and at least one other timestamp corresponding to time of a clock of the at least one wireless sensor, and determining a relative clock offset of the at least one wireless sensor using the timestamps.