A technique for decoding information from multiple, simultaneously-transmitted RFID tags using direct sequence spread spectrum

Radio frequency identification (RFID) is currently being employed in several applications particularly objects tracking and inventory control. A technique that enables simultaneous reading of multiple RFID tags will improve speed and accuracy of tracking and identifying processes. However, an RFID system with simultaneously transmitting tags is limited to interference due to collisions. Direct sequence spread spectrum is proved to be a simple and effective method to solve the collision problem especially in a fading multipath environment. The fewest error cancellation algorithm can improves the system performance by reducing errors in direct sequence spread spectrum systems. The power level estimation is an important process to determine the signal powers in the system. Future research will offer wider possibilities for multiple access RFID to be developed and employed in new applications.