Real‐world testbed for multi‐tag UWB chipless RFID system based on a novel collision avoidance MAC protocol

Abstract

Chipless radio frequency identification (RFID) tags are dummy, memoryless, with limited number of bits, very low backscattered power, and short reading range. Therefore, the existing RFID standards and protocols designed for the chipped RFID systems are not applicable for the chipless systems. Main objective of this contribution is to introduce a novel real‐world testbed for multi‐tag ultra‐wideband (UWB) chipless RFID system. In this testbed, a new Notch Position Modulation scheme is implemented as the first medium access control algorithm for handling the multi‐tag identification scenario of the frequency signature based chipless RFID tags. This intelligent Notch Position Modulation algorithm reduces the sensing and identification time and accordingly the overall system latency. The proposed protocol enables fetching the frequency signatures of the chipless RFID tags through the whole UWB range effectively. Moreover, an advanced signaling scheme is designed for the RFID reader in order to make the best use of the Federal Communications Commission UWB regulations for increasing the maximum transmitted power and the corresponding reading range. The signaling scheme, real‐time channel estimation, and clutter removal technique are implemented on the software defined radio platform in a heavily dense multipath indoor environment. Based on the medium access control protocol, the mitigation of the undesired environmental reflections as well as the interference between the chipless RFID tags is well demonstrated in the developed testbed.

A new UHF/ultra wideband‐radio frequency identification system to solve coexistence issues of ultra wideband‐radio frequency identification and other in‐band narrowband systems

“…In RFIDs for those applications, the reader sends power, data, and commands to the tag 9 . A hybrid architecture composed of impulse radio Ultra Wideband‐Radio Frequency Identification (IR‐UWB) and narrowband (NB) Ultra High Frequency (UHF) technologies is a promising candidate for RFID systems because of the data transfer capability from the tag to the reader and precise localization using autonomous tags 10 . The new architecture introduces aggressively duty‐cycling and ultra‐low power UWB transmitter in the tag (for energy saving) while shifting the power‐hungry and complicated UWB receiver to the reader side.…”

Long reading range for the frequency coded Chipless RFID system based on reflectarray antennas

“…The second challenge, is the environmental reflections which are contaminating the tag backscattering signal [2] and this makes the tag unreadable even if it is within the reader reading range. The last major problem is the multi-tag interference [3]. The superposition of the tags responses within a specified interrogation zone cannot be discriminated if the number of tags exceeds an absolute limit.…”

“…The superposition of the tags responses within a specified interrogation zone cannot be discriminated if the number of tags exceeds an absolute limit. These limitations are addressed in the literature from the signal processing point of view [3, 5, 6]. Moreover, the spatial division multiple access is proposed for the time coded chipless RFID tags [7].…”

“…This RA antenna system plays a significant role in increasing the tag reading range and enables the tag detection in a real environment. Furthermore, the contamination of tag response due to the multi-path clutter components is dramatically reduced while exploiting the pencil beam provided by the RA antenna. Chipless RFID Tags: The designed tag is implementing the collision avoidance medium access control (MAC) protocol introduced in [3], which mitigates the multi-tag interference by introducing notch position modulation (NPM) scheme for the tag code.…”

“…Chipless RFID Tags: The designed tag is implementing the collision avoidance medium access control (MAC) protocol introduced in [3], which mitigates the multi-tag interference by introducing notch position modulation (NPM) scheme for the tag code.…”