78 research outputs found
Idle-slots elimination based binary splitting anti-collision algorithm for RFID
Tag collision avoidance is critical to the success of data communications in radio frequency identification (RFID) system. This paper presents an efficient idle-slots elimination based binary splitting (ISE-BS) algorithm to improve the performance of RFID system. In ISE-BS, by introducing 1 bit random number Q and 16-bits random number serial identifier (SID)which are transmitted before data exchange, tag collisions can be informed and unnecessary data exchange between reader and tags can be further eliminated. Moreover, ISE-BS exploits Q to separate conflicting tags into ‘0-1’ subsets randomly. Specifically, the tags in subset ‘0’ will start to transmit in the next period, where the success flag signal reflects the immediate data transmission. The tags in subset ‘1’ will wait in the pipeline. In such a way, the idle slots introduced by conventional binary splitting anti-collision algorithms can be removed with schedule of ISEBS. Extensive simulation results show that ISE-BS outperforms the existing proposed algorithms
A collision resolution algorithm for RFID using modified dynamic tree with Bayesian tag estimation
© 1997-2012 IEEE. A new tree-based anti-collision protocol for radio-frequency identification systems is proposed to achieve a very high tag identification efficiency. The proposed algorithm works in two phases. In the first phase, the number of competing tags is estimated through the proposed Bayesian estimation technique, while in the second phase, tags are identified using our modified dynamic tree algorithm. The system efficiency is mathematically derived and verified through simulation. Numerical results show that the proposed algorithm achieves a tag identification system efficiency of 45% and a time system efficiency of 78.5%, thus outperforming any existing collision resolution algorithms
Energy efficient tag identification algorithms for RFID: survey, motivation and new design
RFID is widely applied in massive tag based applications, thus effective anti-collision algorithms to reduce communication overhead are of great importance to RFID in achieving energy and time efficiency. Existing MAC algorithms are primarily focusing on improving system throughput or reducing total identification time. However, with the advancement of embedded systems and mobile applications, the energy consumption aspect is increasingly important and should be considered in the new design. In this article, we start with a comprehensive review and analysis of the state-of-the-art anti-collision algorithms. Based on our existing works, we further discuss a novel design of anti-collision algorithm and show its effectiveness in achieving energy efficiency for the RFID system using EPCglobal C1 Gen2 UHF standard
Mobile Tag Reading in a Multi-reader Rfid Environment
Radio Frequency Identification (RFID) refers to an emerging technology that intends, but not limited to replace barcode technology. RFID system assures to provide an effective inventorying, tracking and monitoring of any sorts of products in any field of applications. Recently, the large scale deployment of RFID system in supply chain management has necessities the use of multiple readers. Unfortunately, multi-reader RFID system suffers from reader collision problems that severely affect the system performance. Hence, this thesis aims to propose a novel framework for multi-reader RFID system based on Framed Slotted ALOHA protocol. The proposed framework is specific to a scenario in supply chain where a tag affixed to an item is in motion that moves on a conveyor belt and multiple readers which are fixed around the conveyor belt are supposed to read all the items. This work also determines the best pattern for the distribution of the tags on the conveyor belt.Computer Science Departmen
Survey on Lightweight Primitives and Protocols for RFID in Wireless Sensor Networks
The use of radio frequency identification (RFID) technologies is becoming widespread in all kind of wireless network-based applications. As expected, applications based on sensor networks, ad-hoc or mobile ad hoc networks (MANETs) can be highly benefited from the adoption of RFID solutions. There is a strong need to employ lightweight cryptographic primitives for many security applications because of the tight cost and constrained resource requirement of sensor based networks. This paper mainly focuses on the security analysis of lightweight protocols and algorithms proposed for the security of RFID systems. A large number of research solutions have been proposed to implement lightweight cryptographic primitives and protocols in sensor and RFID integration based resource constraint networks. In this work, an overview of the currently discussed lightweight primitives and their attributes has been done. These primitives and protocols have been compared based on gate equivalents (GEs), power, technology, strengths, weaknesses and attacks. Further, an integration of primitives and protocols is compared with the possibilities of their applications in practical scenarios
Improving Group Integrity of Tags in RFID Systems
Checking the integrity of groups containing radio frequency identification (RFID) tagged objects or recovering the tag identifiers of missing objects is important in many activities. Several autonomous checking methods have been proposed for increasing the capability of recovering missing tag identifiers without external systems. This has been achieved by treating a group of tag identifiers (IDs) as packet symbols encoded and decoded in a way similar to that in binary erasure channels (BECs). Redundant data are required to be written into the limited memory space of RFID tags in order to enable the decoding process. In this thesis, the group integrity of passive tags in RFID systems is specifically targeted, with novel mechanisms being proposed to improve upon the current state of the art.
Due to the sparseness property of low density parity check (LDPC) codes and the mitigation of the progressive edge-growth (PEG) method for short cycles, the research is begun with the use of the PEG method in RFID systems to construct the parity check matrix of LDPC codes in order to increase the recovery capabilities with reduced memory consumption. It is shown that the PEG-based method achieves significant recovery enhancements compared to other methods with the same or less memory overheads. The decoding complexity of the PEG-based LDPC codes is optimised using an improved hybrid iterative/Gaussian decoding algorithm which includes an early stopping criterion. The relative complexities of the improved algorithm are extensively analysed and evaluated, both in terms of decoding time and the number of operations required. It is demonstrated that the improved algorithm considerably reduces the operational complexity and thus the time of the full Gaussian decoding algorithm for small to medium amounts of missing tags.
The joint use of the two decoding components is also adapted in order to avoid the iterative decoding when the missing amount is larger than a threshold. The optimum value of the threshold value is investigated through empirical analysis. It is shown that the adaptive algorithm is very efficient in decreasing the average decoding time of the improved algorithm for large amounts of missing tags where the iterative decoding fails to recover any missing tag. The recovery performances of various short-length irregular PEG-based LDPC codes constructed with different variable degree sequences are analysed and evaluated. It is demonstrated that the irregular codes exhibit significant recovery enhancements compared to the regular ones in the region where the iterative decoding is successful. However, their performances are degraded in the region where the iterative decoding can recover some missing tags.
Finally, a novel protocol called the Redundant Information Collection (RIC) protocol is designed to filter and collect redundant tag information. It is based on a Bloom filter (BF) that efficiently filters the redundant tag information at the tag’s side, thereby considerably decreasing the communication cost and consequently, the collection time. It is shown that the novel protocol outperforms existing possible solutions by saving from 37% to 84% of the collection time, which is nearly four times the lower bound. This characteristic makes the RIC protocol a promising candidate for collecting redundant tag information in the group integrity of tags in RFID systems and other similar ones
Modern Random Access for Satellite Communications
The present PhD dissertation focuses on modern random access (RA) techniques.
In the first part an slot- and frame-asynchronous RA scheme adopting replicas,
successive interference cancellation and combining techniques is presented and
its performance analysed. The comparison of both slot-synchronous and
asynchronous RA at higher layer, follows. Next, the optimization procedure, for
slot-synchronous RA with irregular repetitions, is extended to the Rayleigh
block fading channel. Finally, random access with multiple receivers is
considered.Comment: PhD Thesis, 196 page
Advanced Radio Frequency Identification Design and Applications
Radio Frequency Identification (RFID) is a modern wireless data transmission and reception technique for applications including automatic identification, asset tracking and security surveillance. This book focuses on the advances in RFID tag antenna and ASIC design, novel chipless RFID tag design, security protocol enhancements along with some novel applications of RFID
Intelligent Sensor Networks
In the last decade, wireless or wired sensor networks have attracted much attention. However, most designs target general sensor network issues including protocol stack (routing, MAC, etc.) and security issues. This book focuses on the close integration of sensing, networking, and smart signal processing via machine learning. Based on their world-class research, the authors present the fundamentals of intelligent sensor networks. They cover sensing and sampling, distributed signal processing, and intelligent signal learning. In addition, they present cutting-edge research results from leading experts
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DISTRIBUTED PHASED ARRAY ANTENNAS IN WIDE AREA RFID
Ultra High Frequency (UHF) Radio Frequency Identification (RFID) has gained importance over the past two decades in many applications such as stock management, asset
tracking and access control. For wide area applications, Distributed Antenna Systems
(DAS) have been used to obtain good coverage with few antennas by making use of
multiple spatially distributed antennas and phase dithering. This implements a far-field
beamforming that maximises the instantaneous power at a tag. Separately, phased array
antennas have also been used to increase the read range by increasing the effective field
of view of an antenna and overcoming multipath fading through beam steering. This
dissertation explores a combination of both approaches to improve RFID read ranges in
wide interrogation zones.
Distributed antenna arrays are explored in the context of delivering high tag detection
probabilities in a multi-cell RFID system, while maximising inter-antenna separations.
A Distributed Antenna Array System (DAAS) is designed and shown to be capable of
providing comparable performance to a fixed DAS system with fewer antennas. The properties of the system are further studied and its upper performance limit is explored by
modelling a hypothetical perfectly steerable antenna array. The concept of using perfectly
steerable arrays is further explored to propose a cell-less RFID system, in which cell allocation in wide area RFID is replaced with a tag location-based interrogation requiring the
global reader antenna population to be used for interrogation of all tags, leading to significant potential increases in inter-antenna separation, and consequently good coverage
with fewer antennas. It is also argued that this system leads to the avoidance of complex
reader anti-collision policies, since only a single central reader is now required. Finally,
the design of a wide-scan-angle antenna array is presented as a compromise solution for
perfectly steerable antennas, whist still keeping the desired property of being flat panel.
A 3D RFID multi-antenna model is presented and used for simulating and analysing the
various described systems and for system planning
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