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.

翻译：本文提出了一种高效的混合源分离算法，用于解决配备天线阵列的射频识别（RFID）系统中的碰撞问题。我们首先介绍了一种利用零常数模（ZCM）准则、通过梯度下降分离碰撞标签的方法，无需使用导频符号。研究表明，在目标函数设计中仅考虑ZCM特性，可能导致用于恢复标签信息的波束成形器存在显著模糊性。为克服这一局限，我们提出了一种更精细的方法，采用混合目标函数，在ZCM准则基础上引入了新的模糊性提升准则。