Ahmed El-Awamry

Novel notch modulation algorithm for enhancing the chipless RFID tags coding capacity

The main objective of this contribution is to introduce a novel technique for increasing the coding capacity of the Frequency Coded (FC) chipless RFID system. The proposed scheme encodes 4 bits per single resonator exploiting the notch bandwidth and its corresponding frequency position. Hence, 72-bits could be achieved from 2 to 5 GHz preserving the operating frequency bandwidth. Furthermore, a Smart Singular Value Decomposition (SSVD) technique is utilized to estimate the notch bandwidth and ensure low probability of error. Consequently, high encoding efficiency and accurate detection could be achieved with simplified reader design. Likewise, a novel 4 × 5 cm2 tag is designed to fit the requirements of the devised coding technique. Different tag configurations are manufactured and validated with measurements using Software Defined Radio (SDR) platform. The introduced coding methodology is conclusively validated using Electromagnetic (EM) simulations and real world testbed measurements.

Novel Pseudo-Noise coded chipless RFID system for clutter removal and tag detection

In this contribution a novel Frequency Coded (FC) chipless RFID system is introduced to significantly enhance the tag detection. The proposed system exploits the properties of Pseudo Noise (PN) random sequence, as a transmitted signal, to accurately estimate the Channel Impulse Response (CIR). Consequently, the undesired environmental clutter is filtered by a Selective-RAKE receiver. Hence, the tag is accurately identified in a heavily dense multipath environment using neither reference tags for calibration nor the non-practical no-tag deduction process. A real world simulation, based on ray-tracing tool is performed for to verify the system performance. Furthermore, the system testbed is realized on Software Defined Radio (SDR) platforms, where the tag detection is achieved with minimum latency and optimal precision.

A novel co/cross-polarizing chipless RFID tags for high coding capacity and robust detection

The aim of this work is to introduce a novel tag design enhancing the coding efficiency for the Frequency Coded (FC) chipless RFID system. The proposed approach relies on exploiting the backscattered co/cross-polarized signals from a tag excited with a linear-polarized wave. Consequently, the tag signature is encoded into Notch/Peak (N/P) format in two orthogonal planes. Furthermore, the introduced tag design exhibits narrow resonance bandwidth ensuring best utilization of the operating frequency range and sufficient coding capacity with compact tag size. Hence, 80-bit coding capacity is reached employing physical amplitude On Off-N/P (OO-N/P) modulation and N/P-Position (N/P-P) modulation principles. The presence or absence of a resonator resembles the OO-N/P modulation while the shift in the frequency position imitates the (N/P-P) modulation. In addition, the depolarization property increases the probability of tag detection in a real-world heavily dense multi-path environment. An asymmetry crossed dipole structure is employed to facilitate coding in both divergent polarities separately. The manufactured tags are verified in indoor real-world environment to proof the robustness of the introduced tag design and encoding algorithm. In the full paper, various parameters such as reading range, tag miniaturization and angular stability will be investigated.

Novel adaptive sliding window algorithm reducing latency for multi-tag chipless RFID systems

The main contribution of this work is to introduce a novel technique for reducing the latency of multi-tag Frequency Coded (FC) chipless RFID systems, which is defined as the time required for the reader to identify the tagged objects within the same interrogation zone. The frequency scanning methodology, windowing and notch detection are the three main processing blocks that significantly affect the overall system latency.

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

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%.

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

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.

Printable, high coding capacity chipless RFID tags for low-cost item tagging

This work presents two completely printable chipless RFID tags for low-cost item labeling. The first developed tag is based on circular ring resonators where each resonator codifies a tag coding notch position. Therefore, the tag structure is scalable, printable and compact size. Moreover, a novel encoding methodology is employed to preserve the notch width and position while coding. The second developed tag is a depolarizing tag, where the polarization isolation between the reader interrogation signal and the tag response is utilized to minimize the environmental clutter reflections. Furthermore, the tag is scalable, printable and compact size within the credit card format. The proposed tags and their associated physical encoding schemes are validated using EM simulations and real-world testbed measurements.

A novel adaptive spectrum scanning technique for reducing the identification time of the UWB chipless RFID system

The main objective of this contribution is to introduce a novel technique for reducing the time taken from the reader to identify the Frequency Coded (FC) chipless RFID tags existed in the readers interrogation region, system latency. The frequency scanning methodology, number of averaging for clutter removal and hop duration are the three main parameters that significantly affect the overall system latency. Consequently, the Adaptive Frequency Hopping (AFH) methodology is proposed and proofed to be efficient for the chipless RFID systems from the latency and accuracy perspectives. Likewise, the performance of the designed AFH technique is compared with the classical Fixed Frequency Hopping (FFH) methodology with a fine frequency step to validate the accuracy of the proposed technique. A real-world testbed is designed including a Software Defined Radio (SDR) platform by which the proposed adaptive algorithm and classical FFH methodology are implemented. All the measurements are performed in an indoor realized scenario, including the environmental effects. The experiments show that the proposed AFH algorithm significantly reduce the system latency by 58%.

Novel notch detection techniques for Frequency Coded chipless RFID

Notch identification is a major challenge in Frequency Coded (FC) chipless RFID. The main objective of this contribution is to introduce three signal processing techniques for notch identification and detection. The three algorithms are Matched Filter(MF), Window Based- Singular Value Decomposition (WB-SVD) and Dynamic Time Warping (DTW). The algorithms should be able to detect both notch bandwidth and shift in a real environment, where the notch is likely to be highly distorted. In this work both a simulation model and a testbed is performed to analyze and verify each algorithm using fabricated tags.