Adaptive spectrum scanning techniques for reducing the identification time of the frequency coded chipless RFID system

Abstract

The main objective of this contribution is to introduce novel techniques for reducing the time taken from the reader to identify the frequency coded chipless radio frequency identification tags existed in the reader's interrogation region, system latency. The frequency scanning methodology, number of averaging for clutter removal, and hop duration are the 3 main parameters that significantly affect the overall system latency. Consequently, the adaptive frequency hopping (AFH) and adaptive sliding window (ASW) methodologies are proposed and proofed to be efficient for the chipless radio frequency identification systems from the latency and accuracy perspectives. Likewise, the performance of the designed AFH and ASW techniques are compared with the classical fixed frequency hopping methodology with a fine frequency step to validate the accuracy of the proposed methods. Moreover, 4 different coded frequency coded chipless tags are manufactured and used in the measurements. A real-world testbed is designed including a software-defined radio platform by which the proposed adaptive algorithms and traditional fixed frequency hopping methodology are implemented. All the measurements are performed in an indoor realized scenario, including the environmental effects. The experiments show that the proposed AFH combined with ASW algorithms significantly reduce the system latency by 58%.

A Review of Chipless RFID Measurement Methods, Response Detection Approaches, and Decoding Techniques

“…When it comes to custom-designed frequency-domain systems, scalar, homodyne, and superheterodyne architectures have also been reducing read time/system latency, and mitigating selfinterference due to signals from the transmitter leaking into the receiver sub-section of the reader. By the virtue of lacking phase information, scalar readers also suffer from calibrationbased limitations and high receiver noise power [82,86,186,254,[258][259][260][261][262][263]. In addressing the issue of self-interference, selfinterference cancellation boards [86], an UWB compensation unit based on a polyphase power divider [186,235], a compensation unit based on wideband differential phase shifters [264], and a wideband directive filter have been proposed [260].…”

“…For both frequency-domain and time-domain readers, numerous techniques have been proposed in the literature for increasing performance. These include implementing features like a handshaking algorithm for detecting if a tag is present in order to reduce power consumption [276], selectively silencing the transmitter to allow for increased radiated power while interrogating the tag [235], using a fast locking phase-locked loop (PLL) to allow for higher transmitted power [186], including adaptive frequency hopping and adaptive sliding window methods to reduce read time [262,263], and using ZF equalization to improve the tag detection rate [277]. Increasing the number of receiver antennas to increase receiver diversity, using a Selective-RAKE receiver to filter clutter, using dual signal sources to intentionally create different interrogating wave polarizations, and creating a reader that can read tags in two polarizations without changing the orientation of the reader antenna have also been proposed [98,242,278,279].…”