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A practical implementation of ternary query tree for RFID tag anti-collision
Abstract
A tag-collision problem (or missed reads) in Radio Frequency Identification (RFID) system is the event that a reader cannot identify the tag if many tags respond to a reader at the same time. The so-called M-ary (M=2, 4, 8, ...) query tree protocols were proposed for tag collision arbitration. Mathys et al. showed that ternary (M=3) query tree will bring about the optimum performance for tag identification. However, a ternary tree is impossible in the query tree protocol. In this paper, we propose a practical implementation of a ternary query tree (TQT) for identifying a binary EPC. Simulation results reveal our TQT outperforms the M-ary query tree.
... TQT protocol is hard to implement from binary EPC. In [14], the authors adopted a conversion of 3B2T (3 binary code to 2 ternary code), to practically implement TQT protocol. ...
A tag-collision (or missed reads) in RFID system (Radio Frequency Identification) system degrades the identification efficiency. The so-called tag collision is that a reader cannot identify a tag when more than one tags respond to a reader at the same time. There are some major anti-collision protocols on resolving tag collision, e.g., ALOHA-based protocol, binary tree protocol, and Query Tree (QT) protocol. Up to date, most tag anti-collision protocols are QT protocols. QT protocols are categorized into M-ary query tree (QT). In the previous literature, choosing M = 3 (i.e., a ternary QT (TQT)) was proven to have the optimum performance for tag identification. Recently, Yeh et al. used parallel response approach to reduce the number of collisions. In this paper, we combine the partial response and TQT to propose an effective parallel response TQT (PRTQT) protocol. Simulation results reveal that our PRTQT outperforms Yeh et al.’s protocol and TQT protocol.
... ), the reader generates four new prefixes by setting the first two collided bits 00, 01, 10 or 11, respectively:the new query prefix=the old query prefix + 00, 01, 10 or 11. Then the four new prefixes are pushed into the query stack for the following use [17,18]. b) If it is a CS case(z <0.75 ), the reader generates two new prefixes by setting the first one collided bits 0 and 1, respectively:the new query prefix=the old query prefix + 0 or 1. ...
A novel anti-collision algorithm in RFID wireless network is proposed. As it is put forward on the basis of collision tree(CT) and improved collision tree(ICT) anti-collision protocols, we call it adaptive collision tree protocol(ACT). The main novelty of this paper is that the AD strategy is introduced and used in ACT to decrease collisions and improve the tag system throughput. AD strategy means that query strings will divide into two or four branches adaptively according to the label quantity. This scheme can decrease both depth of query and collision timeslots, and avoid producing too much idle timeslots at the same time. Both theoretical analysis and simulation results indicate that the novel proposed anti-collision protocol ACT outperforms the previous CT and ICT protocols in term of time complexity, system throughput, and communication complexity.
... Tags are allowed to transmit their IDs in the given time slot, and thus the number of probability of tag collision will reduce. Query-tree (QT) [21,22,23,24,25] is another popular protocol for tag anti-collision. In tree-based algorithms, each tag corresponds to the leaf-node of a full binary-tree, and each query string of the reader matches each node of the tree. ...
The rapid proliferation of Radio Frequency IDentification (RFID) systems
realizes integration of physical world with the cyber ones. One of the most
promising is the Internet of Things (IoT), a vision in which the Internet
extends into our daily activities through wireless networks of uniquely
identifiable objects. Given that modern RFID systems are being deployed in
large-scale for different applications, without optimizing reader's
distribution, many of the readers will be redundant, resulting waste of energy.
Additionally, eliminating redundant eaders can also decrease probability of
reader collisions, as a result, enhancing system performance and efficiency. In
this paper, an overlap aware (OA) technique is proposed for eliminating
redundant readers. The OA is a distributed approach, which does not need to
collect global information for centralizing control, aims to detect maximum
amount of redundant readers could be safely removed or turned off with
preserving original RFID network coverage. A significant improvement of the OA
scheme is that the amount of "write-to-tag" operations could be largely reduced
during the redundant reader identification phase. In order to accurately
evaluate the performance of the proposed method, it was performed in a variety
of scenarios. The experiment results show that the proposed method can provide
reliable performance with detecting higher redundancy and has lower algorithm
overheads as compared with several well known methods, such as the RRE, LEO,
the hybrid algorithm (LEO+RRE) and the DRRE.
A tag collision problem (or missed reads) in Radio Frequency Identification (RFID) system happens when multiple tags respond to a reader simultaneously. At this time, the reader cannot differentiate these tags correctly. This problem is often seen whenever a large volume of RFID tags are read together in the same radio frequency field. Tag collisions will degrade identification efficiency, and this unreliable identification will compromise the usefulness of RFID system. This chapter introduces tag collision problem and discusses tag anti-collision protocols, including ALOHA-based protocol, Binary Tree (BT) protocol, and Query Tree (QT) protocol. To date, most tag anti-collision protocols are QT protocols. Thus, in this chapter, the authors briefly describe some elegant researches on QT protocols, and also introduce their recent research results on QT protocols.
In this letter, we present a dynamic adaptive multi-tree search (DAMS) algorithm which is an improvement of a multi-tree search algorithm (AMS). In order to reduce collisions, the multi-tree search algorithm adjusts the search tree through collision factor (CF). The proposed algorithm puts forward a new CF critical value and stipulates that the length of EPC which tags replied dynamically. The simulation results show that the DAMS search timeslots decrease about 20% than AMS, meanwhile DAMS reduces 70% transmission data than AMS.
A theory to allocate a wavelength in the tree networks coordinated arrangement in m-arity networks is proposed. Wavelength required equations to support all-to-all unicasting in the network according to its depth are presented. Three cases are examined: when nodes are only targets, sources or target and source in the same time. The trade-off between wavelength cost and wavelength conversion cost is considered; therefore, concentration is on wavelength allocation without conversion.
A reader must be able to identify tags as quickly as possible, so tag anti-collision is a significant issue for the RFID system. In this paper, we propose a novel tag anti-collision protocol (ACQT), which is suitable for a large mobile tags environment. Based on a 3-ary tree, it has the optimal capacity to identify for tree-based protocols. Using a combination query tree, it can solve the problem of not being able to generate a 3-ary tree when the length of a tag's ID is not a multiple of 3. The joining and leaving strategies can efficiently be applied for tag mobility. The simulation results show that the protocol we present can achieve better performance than previous protocols by decreasing identification delay, collision cycles and idle cycles.
In this paper, we propose a hybrid query tree protocol that combines a tree based query protocol with a slotted backoff mechanism. The proposed protocol decreases the average identification delay by reducing collisions and idle time. To reduce collisions, we use a 4-ary query tree instead of a binary query tree. To reduce idle time, we introduce a slotted backoff mechanism to reduce the number of unnecessary query commands. For static scenarios of tags, we extended the proposed protocol by adopting two phases. First, in leaf query phase for existing tags, the interrogator queries leaf -nodes directly to reuse query strings in the previous session. Second, in root query phase for new arriving tags, the interrogator starts the query process from the roof -node. Simulation reveals that the proposed protocol achieves lower identification delay than existing tag collision arbitration protocols regardless of whether tags are mobile or not.
In this paper we present a new tree search-based protocol for the anti-collision problem of RFID systems. This protocol builds a binary search tree according to the prefixes chosen randomly by tags rather than using their ID-based prefixes. Therefore, the tag identification time of the proposed protocol is no longer limited by the tag ID distribution and ID length as the conventional tree search protocol. The time complexity of the protocol is derived and shown that it can identify tags faster than the Query-Tree protocol.
Tag identification is an important tool in RFID systems with ap- plications for monitoring and tracking. A RFID reader recognizes tags through communication over a shared wireless channel. When multiple tags simultaneously transmit their IDs to a reader, the tag signals collide and this collision disturbs the reader's iden- tification process. Therefore, tag collision arbitration for passive RFID tags is a significant issue for fast identification. This paper presents two adaptive tag anti-collision protocols, an Adaptive Query Splitting protocol (AQS), which is an improvement on the query tree protocol and an Adaptive Binary Splitting protocol (ABS), which is based on the binary tree protocol, which is a de facto standard for RFID anti-collision protocols. To reduce colli- sions and identify tags efficiently, adaptive splitting protocols use information obtained from the last process of tag identification. Our performance evaluation shows that AQS and ABS outper- form other tree based tag anti-collision protocols.
Tag identification is an important tool in RFID systems with applications for monitoring and tracking. A RFID reader recognizes tags through communication over a shared wireless channel. When multiple tags transmit their IDs simultaneously, the tag-to-reader signals collide and this collision disturbs a reader's identification process. Therefore, tag collision arbitration for passive tags is a significant issue for fast identification. This paper presents two adaptive tag anticollision protocols: an Adaptive Query Splitting protocol (AQS), which is an improvement on the query tree protocol, and an Adaptive Binary Splitting protocol (ABS), which is based on the binary tree protocol and is a de facto standard for RFID anticollision protocols. To reduce collisions and identify tags efficiently, adaptive tag anticollision protocols use information obtained from the last process of tag identification. Our performance evaluation shows that AQS and ABS outperform other tree-based tag anticollision protocols.
The throughput characteristics of contention-based random-access systems (RAS's) which use Q -ary tree algorithms (where Q geq 2 is the number of groups into which contending users are split) of the Capetanakis-Tsybakov-Mikhailov-Vvedenskaya type are analyzed for an infinite population of identical users generating packets according to a Poisson process. Both free and blocked channel-access protocols are considered in combination with Q -ary collision resolution algorithms that exploit either binary ("collision/no collision") or ternary ("collision/ success / idle") feedback. For the resulting RAS's, functional equations for transformed generating functions of the first two moments of the collision resolution interval length are obtained and solved. The maximum stable throughput as a function of Q is given. The results of a packet-delay analysis are also given, and the analyzed RAS's are compared among themselves and with the slotted ALOHA system in terms of both system throughput and packet delay. It is concluded that the "practical optimum" RAS (in terms of ease of implementation combined with good performance) uses free (i.e., immediate) channel access and ternary splitting (i.e., Q = 3 ) with binary feedback.
A so-called tag-collision problem (or missed reads) in Radio Frequency Identification (RFID) system is the event that a reader cannot identify the tag if many tags respond to a reader at the same time. In this paper, we propose an adaptive query tree (AQT) protocols that combine the multiple M-ary trees. The large M reduces collisions, while the small M avoids the unnecessary inquiries. Our AQT protocol successfully decreases the identification time by reducing the collisions and the idle time simultaneously. Two variant modes were proposed in our AQT, the base AQT (BAQT) and the modified AQT (MAQT), designed for the random electronic product code (EPC) and the very similar EPC with the first half bits are identical. Simulation results reveal that the proposed BAQT and MAQT outperform the base query tree.
One of the challenges in designing modern RFID systems is that when more than one tag exists in an RFID environment, it may occurs collisions so that the whole system becomes inefficient and increases the time for identifying RFID Tags. In order to simultaneously recognize several tags within a reader interrogation zone, an anti-collision algorithm should be applied. In this paper, we present an Enhanced Query Tree (EQT) protocol for memoryless tag anti-collision in RFID networks. The EQT is an enhanced technique based on the query tree protocol. The main advantage of EQT is that it can dynamically adjust length of prefix code to avoid unnecessary inquiry and reduce collisions. To evaluate performance of the proposed techniques, we have implemented the EQT along with the query tree protocol. The experimental results show that the EQT outperforms other tree based protocols in terms of the identification efficiency and its overhead, including number of collisions and time cost. Particularly, the EQT performs very well in neutral RFID systems.
Radio Frequency Identification (RFID) technology uses radio-frequency waves to automatically identify people or objects. A large volume of data, resulting from the fast capturing RFID readers and a huge number of tags, poses challenges for data management. This is particularly the case when a reader simultaneously reads multiple tags and Radio Frequency (RF) collisions occur, causing RF signals to interfere with each other and therefore preventing the reader from identifying all tags. This problem is known as Missed reads, which can be solved by using anti-collision techniques to prevent two or more tags from responding to a reader at the same time. he current probabilistic anti-collision methods are suffering from Tag starvation roblems so not all tags can be identified, while the deterministic methods suffer from too long Identification delay. In this paper, a “Unified Q-ary Tree Protocols” based on Query tree is presented. In empirical study compared with the Query tree and 4-ary tree, we show that the proposed method performs better, it requires less number of queries per complete identification, which results in less total identification time. Yes Yes
Unified q-ary tree for RFID tag anticollision resolution
- P Pupunwiwat
- B Stantic
P. Pupunwiwat, B.Stantic, "Unified q-ary tree for RFID tag anticollision resolution," in 2009 Proc.20th Australasian Database
Conference, pp. 49-58.