Sensor data compression

In one embodiment, a method includes receiving motion data from a motion sensor during a packet-transmission interval of a wireless protocol. The motion data corresponds to a first pre-determined number of samples measured at a first sampling frequency. Each sample is associated with a first timestamp corresponding to a measurement time of that sample during the packet-transmission interval. The method also includes converting the motion data to correspond to a second pre-determined number of samples. The second pre-determined number is fewer than the first pre-determined number. The method also includes determining a second timestamp for each of the second pre-determined number of samples. The second timestamps are within the packet-transmission interval and represent measurement times at a second sampling frequency that is lower than the first sampling frequency. The method also includes combining the converted motion data and the corresponding second timestamps into a first data packet.