Patent ID: 8941472
Filing Date: 2015-01-27
Classification: G06K,H03M,H04L

Abstract:
1. A method for decoding an RFID data signal received from an interrogated RFID tag using an RFID receiver, comprising: sampling a received signal including the RFID data signal comprising a sequence of symbols transmitted from the interrogated RFID tag; providing a first set of predetermined probabilities of the received sequence of symbols related to a transition between data states in a first direction, where each predetermined probability is related to data, timing and baud rate variables affecting the received signal; applying the first set of predetermined probabilities to each of a plurality of pairs of signal sample subsequences to determine first probabilities of the received RFID data signal making the specific transition between data states in the first direction; providing a second set of predetermined probabilities of the received sequence of symbols related to the transition between data states in a second opposite direction; applying the second set of predetermined probabilities to each of the plurality of pairs of signal sample subsequences to determine second probabilities of the received RFID data signal making the specific transition between data states in the second opposite direction; and processing the first and second determined probabilities to recover the RFID data signal.