Patent ID: 7844221

Claim:
A reflective communication system, comprising: a plurality of transmitters configured to operate on the same frequency, wherein each transmitter of the plurality of transmitters is physically separate from the rest of the plurality of transmitters, and wherein each transmitter of the plurality of transmitters is configured to transmit a communication signal that is spread with a spread spectrum code associated with the transmitter; a plurality of wireless communication devices located in the transmission field of the plurality of transmitters and configured to receive communication signals transmitted from the plurality of transmitters, wherein the plurality of wireless communication devices are further configured to reflectively modulate the communication signals with data signals having a modulation to form reflected data signals; and a receiver configured to: store, in a receiver memory, a spread spectrum coding sequence containing a plurality of receiver spread spectrum codes, wherein each receiver spread spectrum code correlates to a spread spectrum code respectively associated with a transmitter of the plurality of transmitters; store, in the receiver memory, information indicating a physical location of each transmitter of the plurality of transmitters; receive the communication signals transmitted from the plurality of transmitters; receive the reflected data signals from the plurality of wireless communication devices; and for each reflected data signal that is received: determine the communication signal that was reflectively modulated to form the reflected data signal; determine a time delay between receipt of the reflected data signal and receipt of the determined communication signal; determine the spread spectrum code that was used to spread the determined communication signal, wherein the spread spectrum code is determined using the spread spectrum coding sequence stored in the receiver memory; using the determined spread spectrum code, determine which of the plurality of transmitters transmitted the determined communication signal; and determine an approximate location of the wireless communication device that formed the reflected data signal based on the determination of the transmitter that transmitted the determined communication signal, the determined time delay, and the stored information indicating the physical location of the transmitter that transmitted the determined communication signal.