A High Throughput CDMA-Based Reader Collision Avoidance Protocol for RFID Networks (HRCP)

A typical Radio frequency identification system (RFID) includes one reader and a number of tags. The reader transmit to commands to the tags with interrogation radio signals, and tags receive the command and then respond with their identification. Readers with interrogation signals can read tags’ responses. In RFID systems, when multiple tags respond to one reader simultaneously, tag collision can occur. In addition, multiple reader to tag collision occurs when more than one reader wants to read one tag at the same time. RFID collision problems are a group of the open research topics. In this paper, a high-throughput reader collision avoidance protocol based on code division multiple access (CDMA) has been proposed to solve the reader collision problem with the help of RFID network systems based on orthogonal codes, which allow all readers to read the tags at the same time and frequency. Comparison of this protocol with the pulse protocol shows great improvement on the average read throughput.