The application of the CMA blind equalization in UHF RFID system

The "Gen2" specification for UHF passive RFID system released by EPC global has been paid great attention in recent years. A Gen2 tag derives its power from the RF wave emitted by a Gen2 RFID reader and responds reader\´s interrogation command with its modulated backscatter signals. The readability of a Gen2 tag is often influenced by the problem of multipath fading and inter-symbol interference (ISI). In the paper, the constant-modulus blind equalization algorithm (CMA) is used to reduce the bit error rate (BER) of RFID transmission and to strengthen the channel adaptation capability. The CMA blind equalization algorithm is of low computational complexity, easy real-time realization and good convergence performance, which made it suitable for the request towards the computation of RFID system. Compared with the method without using any signal processing, the proposed algorithm is of lower BER and better channel adaptation capability, which is confirmed by computer simulation.