A Widely Linear MMSE Anti-Collision Method for Multi-Antenna RFID Readers

Abstract

In a multi-tag radio frequency identification (RFID) system, signals sent from different tags are likely to interfere with others, leading to a degradation in the transmission quality. To solve this problem, a novel widely linear minimum-mean-square-error (WLMMSE) anti-collision method is proposed by taking into account the improper second-order statistics of backscattered tag signals, which result from the quadrature nature of RFID readers. The proposed method provides an efficient means to separate multiple overlapping tag signals within a single time slot and can be easily integrated into multi-antenna RFID systems to improve their throughput. Its modeling advantages over conventional linear model-based signal recovery methods are illustrated by both the simulations and real-world experiments.