Error detection based on correlation analysis for BCH encoded UHF RFID communication

Abstract

To accomplish a reliable detection of goods and items over a couple of meters Long Range Radio Frequency Identification (RFID) is a common used wireless transmission technique. Most of the commercial systems use a transmission with passive transponders (tags) which backscatter their information back to a processing unit (reader). This communication is realized in the Electronic Product Code (EPC) Class-1 Gen-2 protocol. In the Gen-2 protocol only a CRC code is used, which can detect transmission errors very reliably but can not correct any errors. So a possible extension to this protocol is the implementation of Forward Error Correction (FEC). Because of its similarity with the CRC code a BCH code can be used. For the small scale fading characteristic and the dyadic backscatter channel a coding gain up to 8 dB regarding the bit error rate can be achieved during an RFID transmission. The disadvantage of a BCH decoding without any additonal error detection is however, that the decoder can not decide if a decoded package is false when the erroneous codeword is wronly detected as another correct codeword. This may lead to falsely detected packages especially for low SNR. This paper shows a simple technique which uses the information of the spreading sequences in the Gen-2 protocol for a detection of erroneous packets. It is shown that the combination of BCH FEC and reliability detection outperforms the conventional CRC-based transmission regarding the time to read a particular tag population in many cases.

Improving UHF RFID read rates by juggling selected bits

“…Alternative approaches replace the CRC by codes which provide error correction functionality but do not conform to the standard: In [17] BCH codes are used for FEC as they are supposed to be similar to the used CRC codes and are therefore easily implemented. The proposed approach provides a coding gain of up to 8 dB for the BER.…”

“…A common approach uses a less accurate but simpler common Rayleigh fading channel with AWGN (e.g., in [13], [17], [18]). As small scale fading is highly specific for the considered scenario and not generally transferable, the authors of [1] focus on AWGN and Burst Noise instead.…”

Survey of Security Challenges in NFC and RFID for E-Health Applications

“…For example, channel models have been proposed for RFID networks in (Smietanka & Gotze, 2012;Choudhury & Smith, 2014;Malison et al, 2008;Arnitz et al, 2010;Li et al, 2011;Chen et al, 2011). The goal of those studies is to determine optimal communication performance in terms of lower OSI layer metrics such as antenna diversity gain, signal-to-noise ratio, bit error rate, path loss, etc.…”

Forward error correction in passive UHF Gen2 communications

“…Smietanka et al [38] propose the implementation of the BCH FEC codes into passive UHF RFID protocols. The au-thors argue BCH could be easily adapted to the Gen2 protocol because of BCH code's similarity to CRC.…”