Methods, apparatus and systems for monitoring a presence or a motion of an object in a proximity of an apparatus are described. In one example, a described apparatus is in a venue for wireless proximity monitoring. The apparatus comprises: a transmitter, a receiver, and a processor. The transmitter is configured for transmitting a wireless signal through a wireless multipath channel, wherein the wireless multipath channel is impacted by a motion of an object within a proximity of the apparatus. The receiver is configured for: receiving the wireless signal through the wireless multipath channel between the transmitter and the receiver, and obtaining a time series of channel information (TSCI) of the wireless multipath channel based on the wireless signal received by the receiver. The processor is configured for monitoring the motion of the object within the proximity of the apparatus based at least partially on the TSCI.