Outage Probability of Equal Gain Combining for Backscatter Communication Systems Over Nakagami-m Fading Channels

In this paper, we propose a multi-tag equal gain combining (EGC) scheme for the radio frequency identification (RFID) communication system. Different from the traditional communication systems, the forward link channel and backscatter link channel in RFID system can be fully correlated, partially correlated and uncorrelated for the special architectures. We have derived the exact outage probabilities of the proposed scheme by using the characteristic function (CHF) for the three channel correlation cases. Furthermore, we also present the asymptotic CHF expression, from which the diversity order of the proposed scheme can be obtained directly. The EGC diversity scheme applied in the multi-tag scenario can mitigate the double fading of the RFID channel and improve the system performance. Finally, simulation results are provided to verify our theoretical analysis.