A mobile device comprising: i) receive path circuitry configured to detect signals transmitted by a plurality of wall-mounted beacons in a structure in which the mobile device is located, the receive path circuitry further configured to determine a received signal strength indicator (RSSI) value associated with each detected beacon and to determine an identification (ID) value transmitted by each detected beacon; ii) a memory configured to store a floor plan of the structure; and iii) processing circuitry configured to identify a first detected beacon and a second detected beacon mounted on opposing sides of a first wall using the floor plan and the transmitted ID values of the first and second detected beacons. The processing circuitry uses the RSSI value of the first detected beacon and the RSSI value of the second detected beacon to determine if the mobile phone is on the same side of the first wall as the first detected beacon or the second detected beacon.