Problem: The listener associates itself with the ``wrong'' space identifier

Figure 2.3: Incorrect placement of beacons to for boundary detection between two spaces.

Figure 2.4: Correct beacon placement.

When using Cricket beacons to delimit spaces that are not separated by a wall, both RF and ultrasound from the beacons in the two different spaces may traverse the other space. Because the listener associates itself with the space advertised by the nearest beacon, you need to place beacons with some care to achieve proper spatial demarcation. Figure 2.3 illustrates a bad configuration of beacons, where a listener on the left side of the partition could be closer to the beacon on the right, causing it to associate itself with the wrong space.

Place the beacons corresponding to the different spaces at equal distances from the boundary between the spaces, as shown in Figure 2.4.