The advance in wireless sensor technologies has resulted in many new applications for military and/or civilian purposes. Many cases of these applications rely on the information of personal locations, for example, surveillance and location systems. These location dependent systems are realized by using either identity sensors or counting sensors. For identity sensors, for example, bat and cricket, each individual has to carry a signal sender/receiver unit with a globally unique identifier. With identity sensors, the system can pinpoint the exact location of each monitored person. On the other hand, counting sensors, for example, photoelectric sensors, and thermal sensors, are deployed to report the number of persons located in their sensing areas to a server.