In one aspect, a method of wireless communications includes: storing identification information of a portable wireless communications device in memory coupled to a processing unit of the portable wireless communications device; determining a current location of the wireless communications device using a global positioning system (GPS); performing wireless communications with a cellular communications system using a cellular receiver controlled by the processing unit; generating a random number using an identification device controlled by the processing unit; and modulating a carrier provided from an interrogator wirelessly coupled to the identification device to provide the identification information, including the random number.