Modeling and simulation of MISO diversity for UHF RFID communication

Radio Frequency Identification (RFID) is used in high scattering environments where deep fading exists. This makes diversity particularly interesting for this communication scenario. In this paper the potential of using multiple tag antennas for RFID-communication is shown. The bit error rate (BER) and packet error rate (PER) is presented, which include the backscattering answer of a RFID-Tag according to the EPC Class-1 Gen-2 protocol. The rates are regarded in combination with the relevant fading channel models for RFID communication such as the Rician- and the Dyadic Backscatter Channel. It is shown that the possible diversity gain from the signal according to EPC Class-1 Gen-2 protocol is several dB regarding the error rates. It is also shown that this diversity gain increases with the correlation of the forward and backward link and decreases with the usage of a more robust encoding scheme and a correlation between the several transmission paths. Additionally the performance of Multiple Input Single Output (MISO) system with different spatial and forward/backward correlation situations is regarded to have a detailed view on a correlated RFID transmission system using diversity. The performance of this model is verified, using simulations of this propagation system.