Segmented Cyclic Redundancy Check: a Data Protection Scheme for Fast Reading RFID Tag's Memory

摘要

In the RFID system, a reader recognizes tags through communications over a shared wireless channel. Using the singulation scheme, the reader detects a single tag from a tag population. Further, the reader sometimes requests the memory contents from the tag. The tag responds by backscattering the requested memory words and a CRC-16 is calculated over and attached to the memory words to verify the message. Since CRC is a technique for detecting errors, but not for making corrections when errors are detected, a simple and feasible solution is to retransmit the whole packet if error occurs. Unfortunately, it makes the RFID system very inefficient due to time delay, especially in dense interrogator environment. This paper presents a Segmented Cyclic Redundancy Check (SCRC) algorithm, a simple, efficient and reliable algorithm for fast reading tag's memory. To reduce retransmission times and read tag's memory efficiently, SCRC corrects single-bit errors at first and the whole packet is divided into multiple segments based on the optimal segment length. Our performance evaluation shows that SCRC causes fewer retransmissions and takes shorter delay for reading RFID tag's memory than existing CRC algorithm.