A MIMO-based backscattering RFID with interleave division multiple access for real-time sensing applications

Radio Frequency Identification (RFID) enabled wireless sensing applications require reliable multi-parameter and multi-tag sensory data transmission in real-time manner. This paper presents a MIMO-based backscattering RFID system, aiming at enhancing the communication robustness by means of a deterministic anti-collision scheme. The proposed interleave division multiple access (IDMA) mechanism not only avoids complex channel estimator but also eliminates synchronization requirements between tags and the reader, significantly simplifying tag implementation complexity. In addition, the adoption of cascaded interleaver saves channel bandwidth efficiently, and the use of Expectation Maximization algorithm broadens the application scope when Channel State Information (CSI) is unknown. The simulation results show that the proposed scheme can improve BER by 20dB under 1/8 coding rate than conventional RFID sensor systems, and support joint detection of up to 48 tags.