FM0 decode for collided RFID tag signals with frequency drift

In a UHF RFID system, frequency drift is very common and will affect to decode RFID tag signals. When the frequency drift occurs, the performance of traditional decoding algorithms will degrade. In this paper, we introduce an FM0 decoding algorithm against the frequency drift. The introduced algorithm could effectively decode from the collided signals into a tag's ID through where a true positive or negative edge is. From experimental results, the performance of bit error rate (BER) for the introduced algorithm is better than the traditional algorithms under the condition of frequency drift.