Anti-collision techniques for RFID systems.

Chiang Kong Wa.Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.Includes bibliographical references (leaves 74-79).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 2 --- Technology Overview --- p.4Chapter 2.1 --- Components of RFID Systems --- p.5Chapter 2.1.1 --- Tag --- p.6Chapter 2.1.2 --- Reader --- p.9Chapter 2.1.3 --- Software systems --- p.10Chapter 2.1.4 --- Communication infrastructure --- p.11Chapter 2.2 --- Frequency Regulations and Standards --- p.11Chapter 2.2.1 --- RFID frequency bands --- p.11Chapter 2.2.2 --- Standards --- p.12Chapter 2.3 --- Advantages and Limitations of RFID Technology --- p.14Chapter 2.4 --- Applications --- p.17Chapter 3 --- Background of Research --- p.20Chapter 3.1 --- Anti-collision methods for RFID systems --- p.22Chapter 3.1.1 --- Stochastic Anti-collision Protocols --- p.25Chapter 3.1.2 --- Deterministic Anti-collision Protocols --- p.27Chapter 4 --- Even-Odd Binary Tree Protocol --- p.30Chapter 4.1 --- Protocol Description --- p.31Chapter 4.2 --- Time Complexity Analysis --- p.34Chapter 4.3 --- Performance Evaluation --- p.37Chapter 4.4 --- Summary --- p.41Chapter 5 --- Prefix-Randomized Query-Tree Protocol --- p.44Chapter 5.1 --- Tag Identification - Known Tag Set Size --- p.45Chapter 5.1.1 --- Protocol Description --- p.45Chapter 5.1.2 --- Time Complexity Analysis --- p.47Chapter 5.1.3 --- Optimal Initial Prefix Length --- p.50Chapter 5.1.4 --- Optimal Number of Level-1 Nodes --- p.52Chapter 5.2 --- Tag Identification - Unknown Tag Set Size --- p.53Chapter 5.2.1 --- Initial Prefix Length Adaptation Algorithm --- p.54Chapter 5.2.2 --- Computing r*Δ(l) --- p.55Chapter 5.2.3 --- Optimal Choice of Step Size Δ --- p.56Chapter 5.3 --- Performance Evaluation --- p.59Chapter 5.4 --- Summary --- p.64Chapter 6 --- Conclusion and Future Work --- p.68Chapter 6.1 --- Conclusion --- p.68Chapter 6.2 --- Future Work --- p.70Bibliography --- p.7

Protocol-level performance analysis and implementation for anti-collision protocols in RFID systems

In this thesis, we provide an analytical approach to evaluate the performance of anti-collision protocols in Radio-frequency identification RFID systems. The analysis is given at protocol-level using performance metrics such as the number of state transitions and clock cycles involved in the protocols\u27 state diagrams, their power and energy consumption. Different protocols were also implemented at different level of abstractions and accurate power analysis was performed in layout level. Discussion and comparison are based on worst-case scenario that represents the process of identifying the last tag when multiple tags are simultaneously available in the system. In particular, a new protocol is proposed for performance improvement. This protocol not only provides fast tag identification mechanism but also reduces tag\u27s power and energy consumptions as compared to other protocols that were covered in this study

Perfect tag identification protocol in RFID networks

Radio Frequency IDentification (RFID) systems are becoming more and more popular in the field of ubiquitous computing, in particular for objects identification. An RFID system is composed by one or more readers and a number of tags. One of the main issues in an RFID network is the fast and reliable identification of all tags in the reader range. The reader issues some queries, and tags properly answer. Then, the reader must identify the tags from such answers. This is crucial for most applications. Since the transmission medium is shared, the typical problem to be faced is a MAC-like one, i.e. to avoid or limit the number of tags transmission collisions. We propose a protocol which, under some assumptions about transmission techniques, always achieves a 100% perfomance. It is based on a proper recursive splitting of the concurrent tags sets, until all tags have been identified. The other approaches present in literature have performances of about 42% in the average at most. The counterpart is a more sophisticated hardware to be deployed in the manufacture of low cost tags.Comment: 12 pages, 1 figur

From M-ary Query to Bit Query: a new strategy for efficient large-scale RFID identification

The tag collision avoidance has been viewed as one of the most important research problems in RFID communications and bit tracking technology has been widely embedded in query tree (QT) based algorithms to tackle such challenge. Existing solutions show further opportunity to greatly improve the reading performance because collision queries and empty queries are not fully explored. In this paper, a bit query (BQ) strategy based Mary query tree protocol (BQMT) is presented, which can not only eliminate idle queries but also separate collided tags into many small subsets and make full use of the collided bits. To further optimize the reading performance, a modified dual prefixes matching (MDPM) mechanism is presented to allow multiple tags to respond in the same slot and thus significantly reduce the number of queries. Theoretical analysis and simulations are supplemented to validate the effectiveness of the proposed BQMT and MDPM, which outperform the existing QT-based algorithms. Also, the BQMT and MDPM can be combined to BQMDPM to improve the reading performance in system efficiency, total identification time, communication complexity and average energy cost

From M-ary Query to Bit Query: a new strategy for efficient large-scale RFID identification

The tag collision avoidance has been viewed as one of the most important research problems in RFID communications and bit tracking technology has been widely embedded in query tree (QT) based algorithms to tackle such challenge. Existing solutions show further opportunity to greatly improve the reading performance because collision queries and empty queries are not fully explored. In this paper, a bit query (BQ) strategy based Mary query tree protocol (BQMT) is presented, which can not only eliminate idle queries but also separate collided tags into many small subsets and make full use of the collided bits. To further optimize the reading performance, a modified dual prefixes matching (MDPM) mechanism is presented to allow multiple tags to respond in the same slot and thus significantly reduce the number of queries. Theoretical analysis and simulations are supplemented to validate the effectiveness of the proposed BQMT and MDPM, which outperform the existing QT-based algorithms. Also, the BQMT and MDPM can be combined to BQMDPM to improve the reading performance in system efficiency, total identification time, communication complexity and average energy cost

Probabilistic DCS: An RFID reader-to-reader anti-collision protocol

The wide adoption of radio frequency identification (RFID) for applications requiring a large number of tags and readers makes critical the reader-to-reader collision problem. Various anti-collision protocols have been proposed, but the majority require considerable additional resources and costs. Distributed color system (DCS) is a state-of-the-art protocol based on time division, without noteworthy additional requirements. This paper presents the probabilistic DCS (PDCS) reader-to-reader anti-collision protocol which employs probabilistic collision resolution. Differently from previous time division protocols, PDCS allows multichannel transmissions, according to international RFID regulations. A theoretical analysis is provided in order to clearly identify the behavior of the additional parameter representing the probability. The proposed protocol maintains the features of DCS, achieving more efficiency. Theoretical analysis demonstrates that the number of reader-to-reader collisions after a slot change is decreased by over 30%. The simulation analysis validates the theoretical results, and shows that PDCS reaches better performance than state-of-the-art reader-to-reader anti-collision protocol

Evaluation Criteria for Reader-to-Reader Anti-collision Protocols

Technical Repor

An effective frame breaking policy for dynamic framed slotted aloha in RFID

The tag collision problem is considered as one of the critical issues in RFID system. To further improve the identification efficiency of an UHF RFID system, a frame breaking policy is proposed with dynamic framed slotted aloha algorithm. Specifically, the reader makes effective use of idle, successful, and collision statistics during the early observation phase to recursively determine the optimal frame size. Then the collided tags in each slot will be resolved by individual frames. Simulation results show that the proposed algorithm achieves a better identification performance compared with the existing Aloha-based algorithms