Optimum number and optimal location of readers for RFID power tags in buildings inhabitant control applications

Active RFID devices are gaining popularity in usage in many applications such as building evacuation, disaster monitoring, cargo tracking and so on. Equipped with batter cells and ability to send and receive signals distinguished active RFIDs from passive ones and convert them to smart network devices. Power tag is one of a kind in active RFID devices where the tag sends the information when it is in the range of a trigger antenna. RFID devices have long been used for inhabitant monitoring such as monitoring the number of people in the rooms of a building and power tag could play a great role here. However, the problem of finding the best location for trigger antenna to read power tag information is a challenging issue. Moreover, reducing the number of trigger antenna not only saves the cost of installation, it reduces the radio interference between various readers. In this paper, using the simulated annealing, an algorithm was developed to find the minimum number of trigger antennas to have full coverage on all exit passages.