UHF RFID transmission with soft-input BCH decoding

Radio Frequency Identification (RFID) is a wireless communication method mostly used in rough indoor environments. In such environments Forward Error Correction (FEC) is a popular method to improve the transmission quality. However, the common RFID protocol (EPCglobal) only provides error detection based on Cyclic Redundancy Check (CRC) codes. The replacement of this code with an arithmetically similar FEC code improves the transmission and requires only minor changes to the protocol structure. A BCH code fulfills this requirement. Nevertheless, this code has the disadvantage that it uses only hard-coded bits for the decoding process. This work presents a BCH decoding using the Chase algorithm which also takes the soft information of the received sequence into account. It is shown that a coding gain of 1 dB is achievable in an RFID transmission application, compared to a transmission with a common BCH code. Also an estimation of the computational complexity when using the Chase algorithm is given as this complexity generally increases with this modification.