Patent attributes
Methods, apparatus and systems for wireless writing tracking are described. In one example, a described system comprises: a transmitter configured for transmitting a first wireless signal through a wireless multipath channel of a venue; a receiver configured for receiving a second wireless signal through the wireless multipath channel; and a processor. The second wireless signal comprises a reflection of the first wireless signal by a tip of a writing instrument in the venue. The processor is configured for: obtaining a time series of channel information (CI) of the wireless multipath channel based on the second wireless signal, wherein each CI comprises at least one of: a channel state information (CSI), channel impulse response (CIR), channel frequency response (CFR), or received signal strength index (RSSI); and tracking a movement of the tip of the writing instrument based on the time series of CI (TSCI).