A system may include one or more processors and a host unit installed in a support structure of a building, the host unit including a communication module configured to send or receive communication data with at least one or more additional host units installed in the building, where the one or more processors are configured to measure an attribute of the sent or received communication data and detect a presence of an object based on a threshold change in the measured attribute of the sent or received communication data between the host unit and the one or more additional host units. The attribute can be an angle-of-signal (AoS) arrival of the communication between the host unit and each of the one or more additional host units, where the threshold change in the measured attribute is a threshold change in the measured AoS arrival.