Pulse Position Modulation for Active RFID System

Radio frequency identification (RFID) enables everyday objects to be identified, tracked, and recorded. This paper presents a design of N-ary pulse position modulation transmission-only active RFID system for monitoring of large number and high density objects. A burst frame from tag consists of multiple duplicated blink units and the interval between them is randomly selected from predefined interval steps to avoid continuous collision. The reader segments composite pulse streams and performs cross-correlation to recover the overlapped blink unit. The tag can be read in registration state or pattern matching state. Simulations show that the system is power efficient, large capacity, and fast reactive