一种基于维特比解码的超高频RFID读写器解码器设计

A Decoder Design for UHF RFID Reader Based on the Viterbi Decoding Algorithm

车辆管理和生产管理等应用对超高频射频识别(UHF RFID)读写器的灵敏度有很高的要求.读写器数字基带解码器作为接收链路的关键环节,其误码率(BER)性能直接影响读写器的接收灵敏度.维特比解码是一种广泛应用于卷积码的解码算法,利用卷积码中码元间的相互联系实现纠错解码.本文首次将维特比解码移植应用于UHF RFID系统中的FM0编码的解码算法中.该解码器利用FM0编码的记忆性,结合维特比解码的纠错能力来降低误码率.仿真结果表明,该解码器在信噪比(SNR)为7.3dB的条件下,可以将误码率降至10-5.相对于最优接收机结构,该解码算法有2.5dB的信噪比优势.

The applications on the vehicle management and the production management of the ultra-high frequency（UHF）radio frequency identification（RFID）system have high requirement on the sensitivity of the reader.The decoder in the digital baseband is a crucial part of the receive link,the bit error rate（BER）of which has a direct influence on the sensitivity of the reader.The Viterbi decoding is a decoding algorithm widely used in the convolutional code decoding,taking advantage of the interaction of different encoded bits and realizing the forward error correcting.As far as what we learnt from the literature,it is the first time that the Viterbi decoding algorithm is applied to the FM0 decoding in the UHF RFID system.Based on the error correcting ability of the Viterbi decoding,the decoder decreases the BER by exploiting the memory property of the FM0 code.Simulation results show that the Viterbi decoder achieves a BER of 10^（-5） under the Singnal to Noise Ratio（SNR）of 7.3 dB.Compared with the traditional optimal receiver structure,the Viterbi decoder has an SNR benefit of 2.5 dB.