COMPLEX PULSE FORMING TEACHNIQUE USING AM DETECTOR TYPE CIRCUITRY AND THE APPLICATION OF CDMA TO RFID FOR THE SIMULTANEOUS READING OF MULTIPLE TAGS

A novel complex ultra wideband RF pulse forming technique has been implemented in this research, using the coefficients derived from discrete Fourier transform of a virtual pulse train. Incorporated in this technique is a multiple frequency communication systems designed such that transmitter receiver proximity and the fading effect of the individual frequencies make part of a corresponding modulation technique. A code division multiple access (CDMA) application to RFID to greatly reduce read time, while at the same time eliminating inter tag interference, has been investigated with the analysis of a typical cart aisle scenario. With the current rate of growth of inventory world wide there is a tremendous need for more efficient method of data gathering, data storage, and data retrieval. In this dissertation, the application of the CDMA RFID technology has been analyzed to demonstrate the potentials of integrating the RFID technology to the EPC global numbering system

Performance Analysis of Hybrid ALOHA/CDMA RFID Systems with Quasi-decorrelating Detector in Noisy Channels

In this paper we investigate the performance of a hybrid Aloha/CDMA radio frequency identification (RFID) system with quasi-decorrelating detector (QDD). Motivated by the fact that the QDD outperforms the conventional decorrelating detector (DD) in noisy network scenarios, we study and propose using QDD as one of the most promising candidates for the structure of RFID readers. Performance analysis in terms of bit error rate and the RFID system efficiency is considered considering CDMA code collision and detection error. Computer simulations are also performed, and the obtained results of QDD-based structure are compared with those of DD-based one to confirm the correctness of the design suggestion in different practical applications of tag identification and missing-tag detection

A Control Method to Reduce Interferences and Collisions between Multiple RFID Tags and RFID Readers

Radio frequency identification technology (RFID) is one of the fastest developing technologies today. Although it has significant performance in use of Auto-ID applications, the presence of multiple tags in a RFID system can lead to interferences between each tags which is called Collision. There are many method to overcome this issue and this project introduces the use of DS-CDMA technique to overcome this issue. The Simulink simulation environment is used to simulate the use of DS-CDMA in RFID system. The results obtained clearly show the concept of this method is leading to a solution for RFID collision issues. However, the further improvement in simulations and concept of the method is most recommended in future project work

LPDQ: a self-scheduled TDMA MAC protocol for one-hop dynamic lowpower wireless networks

Current Medium Access Control (MAC) protocols for data collection scenarios with a large number of nodes that generate bursty traffic are based on Low-Power Listening (LPL) for network synchronization and Frame Slotted ALOHA (FSA) as the channel access mechanism. However, FSA has an efficiency bounded to 36.8% due to contention effects, which reduces packet throughput and increases energy consumption. In this paper, we target such scenarios by presenting Low-Power Distributed Queuing (LPDQ), a highly efficient and low-power MAC protocol. LPDQ is able to self-schedule data transmissions, acting as a FSA MAC under light traffic and seamlessly converging to a Time Division Multiple Access (TDMA) MAC under congestion. The paper presents the design principles and the implementation details of LPDQ using low-power commercial radio transceivers. Experiments demonstrate an efficiency close to 99% that is independent of the number of nodes and is fair in terms of resource allocation.Peer ReviewedPostprint (author’s final draft

Towards Extended Bit Tracking for Scalable and Robust RFID Tag Identification Systems

The surge in demand for Internet of Things (IoT) systems and applications has motivated a paradigm shift in the development of viable radio frequency identification technology (RFID)-based solutions for ubiquitous real-Time monitoring and tracking. Bit tracking-based anti-collision algorithms have attracted considerable attention, recently, due to its positive impact on decreasing the identification time. We aim to extend bit tracking to work effectively over erroneous channels and scalable multi RFID readers systems. Towards this objective, we extend the bit tracking technique along two dimensions. First, we introduce and evaluate a type of bit errors that appears only in bit tracking-based anti-collision algorithms called false collided bit error in single reader RFID systems. A false collided bit error occurs when a reader perceives a bit sent by tag as an erroneous bit due to channel imperfection and not because of a physical collision. This phenomenon results in a significant increase in the identification delay. We introduce a novel, zero overhead algorithm called false collided bit error selective recovery tackling the error. There is a repetition gain in bit tracking-based anti-collision algorithms due to their nature, which can be utilized to detect and correct false collided bit errors without adding extra coding bits. Second, we extend bit tracking to 'error-free' scalable mutli-reader systems, while leaving the study of multi-readers tag identification over imperfect channels for future work. We propose the multi-reader RFID tag identification using bit tracking (MRTI-BT) algorithm which allows concurrent tag identification, by neighboring RFID readers, as opposed to time-consuming scheduling. MRTI-BT identifies tags exclusive to different RFIDs, concurrently. The concept of bit tracking and the proposed parallel identification property are leveraged to reduce the identification time compared to the state-of-The-Art. 2013 IEEE.This work was supported by the Qatar National Research Fund (a member of Qatar Foundation) through NPRP under Grant 7-684-1-127. The work of A. Fahim and T. ElBatt was supported by the Vodafone Egypt Foundation.Scopu

Merged Search Algorithms for Radio Frequency Identification Anticollision

Nowadays, the Radio Frequency Identification (RFID) system enables the control of many devices over an open communication infrastructure ranging from a small home area network to the global Internet. Moreover, a variety of consumer products are tagged with remotely low-cost readable identification electromagnetic tags to replace Bar Codes. Applications such as automatic object tracking, inventory and supply chain management, and Web appliances were adopted for years in many companies. The arbitration algorithm for RFID system is used to arbitrate all the tags to avoid the collision problem with the existence of multiple tags in the interrogation field of a transponder. A splitting algorithm which is called Binary Search Tree (BST) is well known for multitags arbitration. In the current study, a splitting-based schema called Merged Search Tree is proposed to capture identification codes correctly for anticollision. Performance of the proposed algorithm is compared with the original BST according to time and power consumed during the arbitration process. The results show that the proposed model can reduce searching time and power consumed to achieve a better performance arbitration

Stability Analysis of Frame Slotted Aloha Protocol

Frame Slotted Aloha (FSA) protocol has been widely applied in Radio Frequency Identification (RFID) systems as the de facto standard in tag identification. However, very limited work has been done on the stability of FSA despite its fundamental importance both on the theoretical characterisation of FSA performance and its effective operation in practical systems. In order to bridge this gap, we devote this paper to investigating the stability properties of FSA by focusing on two physical layer models of practical importance, the models with single packet reception and multipacket reception capabilities. Technically, we model the FSA system backlog as a Markov chain with its states being backlog size at the beginning of each frame. The objective is to analyze the ergodicity of the Markov chain and demonstrate its properties in different regions, particularly the instability region. By employing drift analysis, we obtain the closed-form conditions for the stability of FSA and show that the stability region is maximised when the frame length equals the backlog size in the single packet reception model and when the ratio of the backlog size to frame length equals in order of magnitude the maximum multipacket reception capacity in the multipacket reception model. Furthermore, to characterise system behavior in the instability region, we mathematically demonstrate the existence of transience of the backlog Markov chain.Comment: 14 pages, submitted to IEEE Transaction on Information Theor