Dynamic power adjustment for speeding up tag identification time in a RFID System

Anti-collision algorithm is very important in the RFID system, because it decides tag identification time and tag identification accuracy. We propose improved anti-collision algorithms using Bin slot in RFID system. In the proposed algorithms, if the reader memorizes the Bin slot information, it can reduce the repetition of unnecessary PingID command and the time to identify tags. If we also use ScrollAllID command in the proposed algorithm, the reader knows the sequence of collided ID bits. Using this sequence, the reader can reduce the repetition of PingID command and tag identification time. We analyze the performance of the proposed anti-collision algorithms and compare the performance of the proposed algorithms with that of the conventional algorithm. We also validate analytic results using simulation. According to the analysis, for the random tag ID, comparing the proposed algorithms with the conventional algorithm, the performance of the proposed algorithms is about 130% higher when the number of the tags is 200. And for the sequential tag ID, the performance of the conventional algorithm decreases. On the contrary, the performance of the proposed algorithm using ScrollAUID command is about 16% higher than the case of using random tag ID.

Radio-frequency identification (RFID) systems have been deployed to detect and identify missing products by affixing them with cheap passive RFID tags and monitoring them with RFID readers. Existing missing tag detection and identification protocols require the tag population to contain only those tags whose IDs are already known to the reader. However, in reality, tag populations often contain tags with unknown IDs, called unexpected tags. These unexpected tags cause unexpected false positives, i.e. , due to them, missing tags are detected as present. We take the first step toward addressing the problem of detecting and identifying missing tags from a population that contains unexpected tags. Our protocol, RUN, uses standardized frame slotted Aloha for communication between tags and readers. It executes multiple frames with different seeds to reduce the effects of unexpected false positives. At the same time, it minimizes the missing tag detection and identification time by first estimating the number of unexpected tags in the population and then using it along with the false-positive probability to obtain optimal frame sizes and minimum number of times Aloha frames should be executed to mitigate the effects of false positives. RUN works with multiple readers with overlapping regions. It is easy to deploy, because it is implemented on readers as a software module and does not require any modifications to tags or to the communication protocol between the tags and the readers. We implemented RUN along with four major missing tag detection and identification protocols, namely, TRP, IIP, MTI, and SFMTI, and the fastest tag ID collection protocol TH and compared them side by side. Our performance evaluation results show that RUN is the only protocol that achieves required reliability in the presence of unexpected tags, whereas the best existing protocol achieves a maximum reliability of only 67%. RUN identifies 100% of missing tags in the presence of unexpected tags, whereas the best existing protocol identifies a maximum of only 60% of missing tags.

Radio Frequency IDentification (RFID) systems have rich applications in daily life. A crucial problem in RFID systems is to estimate the cardinality of RFID tags. Most exiting probabilistic RFID cardinality estimation algorithms utilize a certain pattern hidden in the response vector formed by the tag responses to make estimators. In this paper, we argue that finding the patterns is actually not necessary! In this paper, we present a novel approach to RFID cardinality estimation by making the full use of the whole response vector. We characterize the critical relationship between the number of RFID tags and the specific distribution of the bits in the response vector. In this paper, we consider two kinds of responses, i.e., empty / non-empty responses and empty / singleton / collision responses. To cater for RFID systems with a very large number of tags, we also generalize our estimation approach to handle geometrically distributed response vectors. Both rigid theoretical analysis and extensive simulations have been conducted and the conclusive results demonstrate that our approach is more accurate than existing state-of-the-art RFID estimation approaches.

RFID 시스템에서 다수의 태그가 동시에 자신의 ID를 리더기에 전송하게 되면 충돌로 인해 리더기의 태그 인식시간이 지연 된다. 따라서 리더기의 태그 인식시간을 줄이기 위한 효율적인 충돌방지 기술이 필요하다. 본 논문에서는 QT(Query Tree) 방식을 기반으로 DFSA(Dynamic Framed Slotted Aloha) 방식을 추가한 hybrid 충돌 회피 방법에 대해서 제안하고 시뮬레이션을 통하여 기존의 방법과 성능을 비교한다. If multiple Tags in the RFID System transmit their IDs to the Reader at the same time, tag identification time is delayed due to collisions. Therefore, to reduce the reader's identification time, an efficient anti-collision technology is needed. In this paper, we propose a hybrid anti-collision method based on the QT and DFSA. Then, the performances of proposed method are compared with the existing method through extensive simulations.

The dynamic frame slot ALOHA (DFSA) algorithm is a typical anti-collision. For the shortcomings of DFSA algorithm, this paper presents an improved algorithm - IDFSA. On the one hand, IDFSA algorithm to improve the label estimation algorithm, so as to achieve dynamic adjustment. On the other hand, through the analysis of mathematics, the new grouping of labels is improved, and the phenomenon of landslide is improved. The simulation results show that the throughput of IDFSA algorithm is higher, and the total operations time is less. RFID (radio frequency identification, RFID) is widely used in logistics, identification, anti-theft and other fields. A traditional RFID system mainly includes two parts: the reader and the tag. In the case of the number of tags more dense, the reader must use the anti-collision to identify the individual tags. So, anti collision algorithm is very important in multi label application field. Tag anti-collision protocols (1) can be categorized into two groups: probabilistic anti-collision methods and deterministic anti-collision methods. The probabilistic anti-collision methods are Aloha-based protocols (2) such as pure Aloha protocol, Slotted ALOHA (SA) protocol, Framed Slotted ALOHA (FSA) protocol and Dynamic Framed Slotted ALOHA (DFSA) (3, 4) protocol. In this paper, an improved dynamic frame slot ALOHA (IDFSA) algorithm is proposed. 2. Related work Frame slotted ALOHA algorithm will be a plurality of time slots set as a frame, for a fixed frame length, when the tag number is less than the length of the frame appears waste the time slot, when the frame length is less than or equal to the number of tags conflict too frequent . In view of this situation, according to the number of tags in the reader range, dynamic adjustment of the next frame length, by a decrease or increase the length of the frame, you can solve the slot waste and tag identification time increased, this method is called dynamic frame slotted ALOHA (DFSA). The analysis of DFSA algorithm shows that the throughput of the system is mainly determined by the estimation of the number of tags and the adjustment of the frame length. The estimation of the number of tags plays a key role in the performance of the algorithm. At present, there are three kinds of label estimation algorithms, Vogt, Schoute and Lowbound

Radio Frequency IDentification (RFID) technology successfully integrates radio transmitter and receiver, small size memory space and control circuitry to remotely store and retrieve data via wireless RF transceiver. As low-cost RFID tag can be massively manufactured by semiconductor industry, new applications associated with RFID technology have emerged rapidly such as inventory tracking, book storage and management, and airport baggage handling. Generally an RFID system is composed of many RFID tags (or tagged objects), at least one RFID reader, and one backend application system with database. An RFID tag gains its operation energy from query signals that are radio waves transmitted by RFID reader. Once a tag responds the query with its stored information to RFID reader, usually a unique identity number or string, the RFID system can recognize the tag carrier and perform required business logic operation. As RFID technique is widely used in supply chain management, the corresponding RFID application systems are expected to process and manage large amount of tagged objects at a predefined period of time regularly. Therefore, for large-scaled RFID applications, tag reading throughput is very critical since it will affect the total data processing time. To measure tag reading throughput of a RFID system, two performance criteria are usually adopted: tag reading delay and reader energy consumption [5]. As RFID reader and tag always communicate over a shared wireless channel, it is very easy to have signal collisions during a normal tag identification process when multiple tags exist in reader’s interrogation area. Signal collision results in query or data retransmission and eventually increases communication overhead and time delay of tag identification. Hence, an efficient tag collision arbitration mechanism is very important and critical for RFID systems to achieve effective performance. Existing RFID tag identification schemes can be classified into aloha-based solutions [3, 10, 12-13, 16, 21, 23-24] and tree-based solutions [1, 2, 4, 6-9, 14-15, 17-20, 22]. In aloha-based schemes, a reader estimates the number of tags in its interrogation area and broadcasts the total number of timeslots to each tag. Then each RFID tag randomly selects its own timeslot to transmit its ID without knowing which timeslots have been selected by other tags. By distributing tag responses to distinct timeslots instead of getting all tag responses at the same time, aloha-based schemes effectively reduce the probability of signal collision. However, aloha-based schemes have tag starvation problem in which certain tags may not

The most important research in the world in these days, research that looking at the internet of thing's (IoT) topics and their applications. Most of these applications depend on RFID system, which includes RFID readers and tags. The important issues in RFID system or network are how we can reduce anti-collision between readers to identify and read tags data. In these paper, we suggest an Improved anti-collision protocol, which can be used to connect RFID readers with RFID tags and reduce the number of RFID tag's collisions. The simulation shows that an Improved Class-1 Generation 2 algorithm is better than Slotted Aloha, Class-1 Generation-2 (Number of Tags Known), Class-1 Generation-2 (Number of Tags Unknown) algorithms.

In this paper, we focus on configuring a low cost RFID (Radio Frequency IDentification) system with less RFID readers and low density RFID tag textiles for stable and accurate self-localization for an omni-directional mobile robot. An RFID system using multiple RFID readers and high density RFID tags has already been applied to an indoor mobile robot self-localization. However, the system production cost is relatively high. To reduce the production cost of the system while maintaining the self-localization performance, we redesign two new RFID systems configured with 20 RFID readers and 5 RFID readers enlarging the size of an RFID reader antenna. Particularly, a new likelihood function of the tag detection with the redesigned large size RFID reader antenna is proposed for Monte Carlo Localization (MCL). Furthermore, we come up with a novel arrangement of RFID tags installed in a hexagon pattern. The new arrangement of ID tags enables both low cost ID tag installation and high performance of self-localization. We examine the performances of robot self-localization with less RFID readers and lower density RFID tags installed on the floor based on MCL(Monte Carlo localization). The simulation demonstrates the validity of our proposed configuration of the RFID based self-localization.

In recent years, numerous authentication protocols for radio frequency identification (RFID) systems have been proposed to protect privacy. Due to the hardware resource limitation on RFID tags, the majority of these protocols are based on symmetric-key ciphers. However, most of them lack scalability at the reader side as they require a linear or logarithmic search proportional to the number of tags in the system in order to authenticate a tag. Recently proposed scalable protocols require a constant-time search and utilize hash look-up tables. However, the storage requirement of the hash-table in these protocols is very large, therefore not practical. Moreover, previous proposals do not support dynamic resizing where the number of tags changes during the life time of the RFID system. In this paper, a new Re-Hash technique is presented to reduce the hash-table storage in constant-time authentication protocols. To the best of our knowledge, it offers the smallest storage cost in comparison to previous proposals. The Re-Hash technique is also further adapted to support the dynamic scalability for RFID systems.

This paper discusses the separation of signals in multiple-tag radio frequency identification (RFID) systems. First, a model for the RFID system in both single and multiple tag environments is presented. Then, an analytical constant modulus algorithm (ACMA) for the blind source separation problem is reviewed. An alternative approach to the traditional ACMA using joint diagonalization is considered. Finally, both the ACMAs are applied to the multiple-tag RFID environment and performance of the system is studied. Simulations are carried out for 4-QAM and 16-QAM modulations at tag and analyses of the simulation results reveal that the ACMA with joint diagonalization takes lesser CPU time to execute compared to the traditional ACMA, but with higher average modulus error (AME). The variation of system performance with the number of measurements, SNR (signal to noise ratio), number of tags and number of antennas at the reader is also studied. Based on these, some design guidelines are presented. Interestingly both the ACMA algorithms work for the 16-QAM case and yield trends similar to those of 8-PSK and 4-QAM.

Dynamic time slot frame ALOHA algorithm is currently the most widely used anti-collision technology in radio frequency identification (RFID) system. Based on the traditional ALOHA algorithm analysis, we propose an improved algorithm. The algorithm is based on a packet adaptive ALOHA anti-collision algorithm (PA-ALOHA). First, the reader scans and counts the time slots which are randomly selected by tags, and sends it to each tag. The tags, then, adjust accordingly the time slot that enable the reader to skip idle slots and collision slots, adaptively allocate effective slots, and then identify tags rapidly. The algorithm employs packet and dynamically adjusts the frame size and other strategies, in order to reduce the time of processing slots. Simulation results show that PA-ALOHA algorithm improves the efficiency and stability of the system and reduce the transmission overhead. Especially, when the number of tags is over 1000, the algorithm throughput is still above 70% that has been greatly improved system efficiency than conventional ALOHA algorithm.

Under-determined blind separation becomes poorer with increasing number of tags, to the point where it cannot separate source tag signals, reducing overall system performance. This paper proposes a parallelizable identification anti-collision algorithm based on non-negative matrix factorization and adaptive ID sequence grouping of binary tree slots. The number of tags in each group can be controlled within the optimum range by selecting a reasonable number to retained source signal separation in the RFID system, which will greatly improve system performance. With the Matlab software numerical calculation and simulation, the results show that tag identification rate improves from 152.8% to 359.2% compared with the blind separation and dynamic bit-slot group algorithm using the same multi-antenna technology for 4–16 antennas, while increasing tag identification speed from 60% to 78.4%. Thus, the proposed algorithm provides high efficiency and low cost and will have very good application for fast identification of large numbers of tags.

This study presents a distributed antenna structure operating at a frequency of 915 MHz to increase the tag identification sensitivity for passive radio frequency identification (RFID) systems. An experimental RFID system is set up to demonstrate the proposed structure. Experimental results indicate that using four distributed patch antennae can improve tag identification in passive RFID systems.

Anti-collision protocols for radio frequency identification (RFID) tag reading processes are designed to reduce the frequency of collisions and to quickly identify all RFID tags during a tag reading collision process. In this paper, we propose a tree-based anti-collision algorithm using a bit change sensing unit (TABCS) based on the bi-slotted collision tracking tree algorithm (BSCTTA) algorithm. The proposed algorithm can identify bits returned from tags using a bit change sensing unit, even in the event of multiple collisions. The algorithm rapidly generates a unique prefix that identifies each tag and reduces the total number of bits. Simulation results show that the proposed algorithm reduces the cost of tag identification compared with legacy algorithms, such as the query tree algorithm with a bit change sensing unit (QT-BCS) or BSCTTA. When the number of tags is 10000, the average number of tags identified per second in TABCS is improved by 4%, and TABCS requires 28% fewer steps to successfully identify one tag compared to BSCTTA.

This paper describes the cluster well central controlled energy-saving device developed for aiming at low efficiency, large energy consumption characteristics of the cluster apheresis well group. The search is based on the oil well production parameters, takes account of the main factor influencing the efficiency of the system of machine production wells, and integrates the following energy-saving innovation technologies: the soft-start control, the dynamic power factor compensation, a common DC bus, stepless frequency converter parameters, and dynamic power adjustment. It realizes the following purposes: optimizing the well production parameters, solving the low running efficiency and large power consumption of the pumping unit, improving the group of low-yielding plexus wells pumping system efficiency, saving energy in scale.