Collision Resolution in RFID Systems Using Antenna Arrays and Mix Source Separation

TL;DR

This paper introduces a novel mix source separation algorithm for RFID collision resolution that leverages antenna arrays and a hybrid objective function to improve tag message recovery without pilot symbols.

Contribution

It presents a new hybrid objective function combining ZCM and ambiguity-raising criteria for better separation of colliding RFID tags.

Findings

Effective separation of colliding RFID tags demonstrated

Hybrid criterion reduces ambiguities in beamformer design

Algorithm improves collision resolution efficiency

Abstract

In this letter, we propose an efficient mix source separation algorithm for collision resolution in radio frequency identification (RFID) systems equipped with an antenna array at the reader. We first introduce an approach that exploits the zero constant modulus (ZCM) criterion to separate colliding tags through gradient descent, without using pilot symbols. We show that the ZCM characteristic, considered alone, in the design of the objective function can lead to significant ambiguities in the determination of the beamformers used in the recovery of tag messages. To address this limitation, we propose a more sophisticated approach, relying on a hybrid objective function, incorporating a new ambiguity-raising criterion in addition to the ZCM criterion.