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In wireless sensor networks, sensing tags are battery powered, which also limits the battery life. Therefore, it is particularly important to study self powered sensing tags. At present, passive wireless identification systems can achieve self powered communication through tags. However, wireless power supply sensing systems have problems such as low efficiency and short communication distance. To reduce the power consumption of sensing tags and improve the efficiency of sensing systems, a passive wireless low-power hydrogen concentration sensing system is designed. To further reduce the power consumption of sensing tags, a passive wireless magnetic field intensity sensing system is developed. In addition, to solve the low efficiency of multiple sensing labels in wireless power supply sensing systems, an efficient anti-collision algorithm based on dynamic binary query trees is designed. According to the research results, in the cold start indoor environment, the energy collection rate of the sensing tag designed in the research was 0.081mJ/s, and the energy collection efficiency was 25.7%. In single/dual sensor mode, the maximum values of sensing error were 2.1% and 5.2%, respectively. The maximum recognition time of the anti-collision algorithm based on dynamic multi base query tree was 2.78s, and the minimum value was 1.31s. The research results can provide methodological and technical support for the improvement of wireless power supply sensing systems, expanding the application range of wireless power supply sensing systems.

With radio frequency identification (RFID) becoming a popular wireless technology, more and more relevant applications are emerging. Therefore, anti-collision algorithms, which determine the time to tag identification and the accuracy of identification, have become very important in RFID systems. This paper presents the algorithms of ALOHA for randomness, the binary tree algorithm for determinism, and a hybrid anti-collision algorithm that combines these two algorithms. To compensate for the low throughput of traditional algorithms, RFID anti-collision algorithms based on blind source separation (BSS) are described, as the tag signals of RFID systems conform to the basic assumptions of the independent component analysis (ICA) algorithm. In the determined case, the ICA algorithm-based RFID anti-collision method is described. In the under-determined case, a combination of tag grouping with a blind separation algorithm and constrained non-negative matrix factorization (NMF) is used to separate the multi-tag mixing problem. Since the estimation of tag or frame length is the main step to solve the RFID anti-collision problem, this paper introduces an anti-collision algorithm based on machine learning to estimate the number of tags. [ABSTRACT FROM AUTHOR]

The basis of the novel anti-collision algorithm is a software implementation that allows theUAV to avoid collisions with environmental obstacles, as well as with other flying objects. The paperuses simplified equations describing the dynamics of the quadcopter to facilitate the modelling ofthe simulation structure. The software implementation of the quadcopter model together with thecontroller is the basis for the operation of the anti-collision algorithm. The model control system usesa three-stage proportional-integral-differential controller. The inspiration of the resulting program ismagnetic interaction. The obstacle avoidance algorithm is based on the measurement of angular valuesand the selection of a proportional virtual force. The force repelling a quadcopter from an obstacle isa parameter that depends on its linear velocity, bearing on the obstacle and distance to the obstacle.The heat maps obtained reflect the scaling of the value and direction of the repulsive force. Afterdefining the target point and the position of the obstacle, the necessary parameters are measured andthe collision course correcting coordinates are selected on-board the quadcopter. The flight parametersof the quadcopter and the control coefficients of the anti-collision algorithm were analysed. Thecorrectness of the program’s operation was checked by simulation using numerous characteristics.Keywords: Unmanned Aerial Vehicle, obstacle avoidance, anti-collision algorithm, UAV dynamicsmodel, quadcopter

In the radio frequency identification technology system, there are too many time slots which are caused by tag collision, and the communication complexity is high. On the basis of the anti-collision algorithm of the binary tree and the quadtree query tree, the methods of locking the collision bit and predicting the child node are used, a new lock-bit hybrid querytree (novel lock-bit hybrid query tree, NLHQT) algorithm is proposed. In the algorithm, the collision bit information is extracted through the lock instruction, and the extracted collision bit information is predicted. While reducing the collision time slot, the reader generates a new query prefix through prediction, thereby avoiding the generation of idle child nodes. Compared with the improved hybrid query tree (IHQT) anti-collision algorithm and the regression lock adaptive multi-tree search (RLAMS), the algorithm in this paper is more effective in reducing the total number of time slots and communication complexity, and the efficiency of identifying tags can be effectively improved. [ABSTRACT FROM AUTHOR]

This paper presents a scalable uplink multiple access (SUMA) protocol for bistatic Wi-Fi backscatter systems, composed of a Wi-Fi reader, Wi-Fi helper, and multiple Wi-Fi backscatter tags. SUMA uses a Wi-Fi reader-initiated dynamic framed slotted ALOHA (DFSA)-based multiple access protocol to minimize collisions caused by simultaneous Wi-Fi backscatter uplink traffic from multiple Wi-Fi backscatter tags. In SUMA, the Wi-Fi helper first estimates the number of tags at the start of network operation and derives an appropriate slot-count parameter (i.e., Q), based on which the frame size is specified. Then, the Wi-Fi helper adaptively adjusts the value of Q to maximize network performance while continuously monitoring the number of remaining Wi-Fi backscatter tags to detect information. An experimental simulation was performed to verify the superiority of SUMA. The results demonstrated that SUMA obtained higher performance in terms of the number of collided and empty slots, delay, and throughput compared with the legacy DFSA approach adopted in the EPCglobal Class 1 Gen 2 standard.

To address the problems of high computational complexity, inflexible frame length adjustment, and sub-optimal system efficiency of the RFID tag anti-collision algorithms in the Internet-of-Things systems, a low-complexity, and universal fast RFID tag anti-collision algorithm is proposed in this paper. A faster and less-complex tag number estimation method depends less on computing and storage resources, making it easier to integrate into the Internet of Things. Using the concepts of sub-frame and system efficiency priority, after each sub-frame is identified, the number of tags is estimated quickly and the frame length is adjusted dynamically to ensure the algorithm's efficiency. Moreover, the proposed algorithm is fully compatible with the EPC Class-1 Generation-2 standard, which ensures its universality and compatibility with the existing systems. The simulation results show that the proposed algorithm can achieve a system efficiency of 0.3554, a time efficiency of 0.7851, and an identification speed of 433 n/s. Compared with the standard Q algorithm, the performance is improved by 9.691%, 5.002%, and 8.250%, respectively. It is, hence, demonstrated that the proposed algorithm meets the requirements for the rapid identification of the RFID tags in the Internet-of-Things applications.

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The work aims at the problem of multi-tag collision in RFID system, then analysis the binary tree algorithm and ALOHA and points out their shortcomings, we proposed a Hybrid of ALOHA and Tree (HAMT) Algorithm. The algorithm first uses the DFSA algorithm for tag identification, and dynamically selects the multi-fork tree algorithm for tag identification based on the number of unidentified tags secondly, thus ensuring that the tag is 100% identified, and improves recognition efficiency and shortens recognition time. The results of the simulation show that when the number of tags is about 1000, the recognition efficiency of the HAMT algorithm can reach around 0.72. So the HAMT algorithm can solve the multi-tag collision problem. [ABSTRACT FROM AUTHOR]

In order to further increase the speed of tag identification, for solving the insensitivity of the frame adjustment in dynamic frame slot aloha algorithm and the high computing complexity of the Q value adjustment in Q algorithm, a new anti-collision algorithm, called continuous slot detection(CSD), is proposed. The idea of algorithm and the process of operation are introduced. In this algorithm, the optimal efficient is obtained by detecting the status of consecutive slots in frame and setting frame length by rules. The simulation results show that compared with other anti-collision algorithm, the proposed algorithm can decrease identification delay by 4% and increase identification speed by 6%.

Anti-collision algorithm is one of key technologies of RFID. This paper proposes a new anti-collision algorithm called InnerQ, based on the Q-algorithm in the EPC Gen2 standard. The proposed algorithm solves the problem of Q value changed frequently and improves the throughput of the system breaking the bottleneck of the ALOHA-based algorithm whose throughput is limited to 36.8%, using the method of reprocessing the collision slots, thus improves the system performance.

This paper studies a novel anti-collision algorithm that is proposed in view of the problem, i.e., label reading collision in radio-frequency identification for Internet of Things. Based on the theoretical foundation of label grouping, the algorithm introduces the Mahalanobis distance and density function to traditional fuzzy C-means clustering grouping algorithm by using EPC code and effectively solves the problem of isolated points of clustering and the optimization problem of initial clustering center. Then, the algorithm realizes effective grouping of labels and distributing identification serial numbers to labels upon the distance from interior labels to the center of clustering. Meanwhile, the efficiency of algorithm can be improved through dynamically setting the frame slot time of readers upon the grouping condition to prevent collision. This paper analyzes the throughput rate theoretically in detail. The simulation results of throughput capacity, throughout rate, and slot efficiency of the algorithm manifest that the algorithm is superior to the most commonly used dynamic binary-tree algorithm and current dynamic ALOHA algorithm in performance.

In order to further improve the accuracy of the tag number estimation algorithms in dense tags environment, based on the analysis and comparison of the tradition al bit estimation algorithms, a novel optimized bit estimation algorithm is proposed. Firstly, based on the binomial distribution theory, the observation of non-selected bits is used to calculate the idle bit rate. Then, a tag number estimation model in dense tags environment is established by determining the threshold of idlebit rate. Finally, the mathematical expression of the relationship between the estimated tag number and the slot consumption is derived. The simulation results show that the proposed algorithm has better estimation accuracy than the traditional bit estimation algorithms and is stable under different numbers of tags. [ABSTRACT FROM AUTHOR]

As an important part of economic development, warehousing logistics also needs to be transformed and upgraded in order to adapt to the development of the new situation. The RFID reader records the related information of the goods to improve the efficiency of warehouse operation by identifying the RFID tags attached to the goods in batches. This paper also proposes an improved group-based anti-collision algorithm (GMQT) to solve the problem of tag collision in the process of Radio Frequency Identification (RFID) identification. The simulation results show that the GMQT algorithm improves the recognition efficiency of the system. The algorithm has the advantages of small data transmission and stable performance; in particular, the recognition efficiency is not affected by the number of tags. [ABSTRACT FROM AUTHOR]

In order to further decrease the probability of the collision and reduce communication complexity, a new low complexity anti-collision algorithm for RFID is proposed using Query Tree. The proposed algorithm can reduce the probability of collision and the traffic of data communication by using tag grouping and setting rules, respectively. The simulation results show that the proposed scheme consumes fewer slots and has lower communication complexity. [ABSTRACT FROM AUTHOR]

RFID technology is an important technology of the Internet of Things. The key to realizing large-scale applications is to improve the efficiency of the system. For this reason, a novel RFID anti-collision Q-value algorithm is proposed, which changes the Q-rounding of the original Q-value algorithm to 2Q rounding, so that the adjusted frame length is closer to the theoretical optimal value, thereby the convergence is effectively reduced. Slot utilization of time is improved. By comparison, the actual throughput of the improved algorithm remains at a high level (average is 0.311 3), the total number of time slots is reduced by 26.7% when it is compared with the original Q-value algorithm. [ABSTRACT FROM AUTHOR]

This paper proposes a type of improved adaptive N-tree anticollision algorithm based on the traditional one for RFID system by combination with maximum likelihood estimation and probe pre-detection. This algorithm inherits some features from Alpha- and tree-based anti-collision algorithms and effectively restrain the star-vation of the two algorithms. It has also filled in the gaps of tag collision with higher probability. The study turns out that the improved adaptive N-tree anti-collision algorithm as proposed can feature adaptive choice of the value N of the tree, length breaks of free timeslots, restraints on defects such as more tag classification and higher collision probability just as what the traditional tree-based algorithm has. N-tree built by level to- level frame identification eliminates the free timeslots, and improves the tag identification precision for the RFID system. The results from simulation experiment reveal that the algorithm proposed in this paper has lower Error Sampling Reckon (ESR) and Throughput Rate Deviation (TRD), and features large throughput rate (87%), low delay of tag recognition and minimum timeslots, and etc. hence to be better applied in large-scale logistics and other fields where fast information recognition is involved. [ABSTRACT FROM AUTHOR]

Copyright of Telecommunication Engineering is the property of Telecommunication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In view of the problem that the recognition efficiency of the system is reduced due to the tag collision in the highly dense radio frequency identification (RFID) system, this paper proposed a lock-bit dual prefix probe anti-collision algorithm. Based on the dual prefix probe anti-collision algorithm .the new algorithm took advantage of the features of Manchester encoding, through lock-bit instructions lock the collision bit, extracted the collision information, and only transmitted part of the information during the subsequent identification process,combined with idea of dual prefix query, in reducing collision slots, while reducing the amount of data transmission. In the design process.it considered three important performance indexes, which were the total timeslots,throughtput and identification efficiency. Theoretical analysis and computer simulations show that the new algorithm has higher recognition efficiency and throughput than the existing algorithms, and is more suitable for RFID identification system. [ABSTRACT FROM AUTHOR]

In order to solve the problem of tag collision in Radio Frequency Identification (RFID) system, the paper proposes a Multi-Bit Identification Collision Tree (MICT) algorithm based on a collision tree. The algorithm uses an array scheme to mark the collision bits in the identification process, and determines the collision information according to the first few bits of the tag, which can effectively reduce the number of recognitions and the amount of communication data. The testing results show that the proposed algorithm reduces the time complexity by about 38% and the communication complexity by about 27% compared to existing collision-tree-based algorithms. Through theoretical analysis and experimental evaluation, the MICT algorithm has obvious advantages in terms of time and communication complexity compared to the other typical algorithms. The algorithm can be applied to the field of RFID-related systems to significantly improve the system efficiency. [ABSTRACT FROM AUTHOR]

As an important part of economic development, warehousing logistics also needs to be transformed and upgraded in order to adapt to the development of the new situation. The RFID reader records the related information of the goods to improve the efficiency of warehouse operation by identifying the RFID tags attached to the goods in batches. This paper also proposes an improved group-based anti-collision algorithm (GMQT) to solve the problem of tag collision in the process of Radio Frequency Identification (RFID) identification. The simulation results show that the GMQT algorithm improves the recognition efficiency of the system. The algorithm has the advantages of small data transmission and stable performance; in particular, the recognition efficiency is not affected by the number of tags.

In the communication process of multiple tags and reader, the tag can not be recognized because of collision during data transmission. In order to solve the problem, this paper analyses the principle of the basic binary algorithm, dynamic binary algorithm and regressive-style binary algorithm. A new algorithm is proposed based on improved regressive-style binary algorithm. The algorithm combines the regressive-style binary algorithm with the dynamic binary search algorithm. In addition, it adopts two collision bits, and introduces the counter. Compared with the original binary search algorithm, the experimental simulation results show that the improved algorithm not only reduces the number of searches, but also improves the algorithm throughput rate. [ABSTRACT FROM AUTHOR]

Traditional anti-collision algorithms determine slot size of initial frame based on the information of number of collision slots , idle slots, and success slots. Since there is no information about collision at the beginning of tag information collection, traditional anti-collision algorithms can not determine the initial frame size. Considering that performance of anti-collision algorithm is very sensitive to initial slot size traditional anti-collision algorithms need some improvements. In this study two methods are proposed to determine slot size of initial frame efficiently, through which we can improve the performance of dynamic frame slotted aloha algorithm. To verify the performance of proposed algorithms, 2.4GHz RFID system is used. Throughput and delay time are derived through simulation, which is developed using JAVA. We have seen that proposed algorithm improves throughput by 9.6% and delay time by 9.8%. [ABSTRACT FROM AUTHOR]

In radio frequency identification systems, some applications require tags to be identified repeatedly. To achieve this, many protocols have been proposed that use information obtained from the previous tag identification process to quickly re-identify tags remaining within the communication range of the reader. However, none of these protocols consider the capture effect, and thus may not be effective in real wireless communication environments. When multiple tags simultaneously reply to a reader, the reader may consider the strongest signal to be a successful transmission rather than a collision and ignore all other replies. In this paper, we propose a new capture-aware anti-collision protocol based on the couple-resolution blocking (CRB) protocol that efficiently identifies tags repeatedly. We demonstrate that the CRB protocol suffers from the capture effect in which some tags may not be identified in practical environments. To solve this problem of the capture effect, we modify the CRB protocol by adopting the state-of-the-art capture-aware anti-collision protocol known as the multi-round collision tree (MRCT) protocol. Through computer simulation, we show that the proposed protocol with MRCT can reduce the number of slots required by approximately 50% in a random topology where most tags remain in the communication range of the reader. [ABSTRACT FROM AUTHOR]

In this paper, we propose a simplified tag collection algorithm to improve the performances of ISO/IEC 18000-7, which is a standard for an active RFID system. The proposed algorithm modifies the collection command that enables to start a tag collection round. The modified collection command includes the results of the listen period response for the previous collection round. Tags that receive the collection command check the collision status for their responses. If there is no collision, tags transmit their additional data and go into the sleep mode without the point-to-point read command and sleep command. A collection round for the standard consists of a collection command and response, a read command and response, and sleep command. On the other hand, in the proposed algorithm, a collection round consists of a collection command and response. The simulation results showed that the proposed algorithm can improve the identification delay about 16% compared with the standard when the number of tags are 300. [ABSTRACT FROM AUTHOR]

In order to solve the problem of tag collision in Radio Frequency Identification (RFID) system, the paper proposes a Multi-Bit Identification Collision Tree (MICT) algorithm based on a collision tree. The algorithm uses an array scheme to mark the collision bits in the identification process, and determines the collision information according to the first few bits of the tag, which can effectively reduce the number of recognitions and the amount of communication data. The testing results show that the proposed algorithm reduces the time complexity by about 38% and the communication complexity by about 27% compared to existing collision-tree-based algorithms. Through theoretical analysis and experimental evaluation, the MICT algorithm has obvious advantages in terms of time and communication complexity compared to the other typical algorithms. The algorithm can be applied to the field of RFID-related systems to significantly improve the system efficiency.

In the fields of production, manufacturing and supply chain management, Radio Frequency Identification (RFID) is regarded as one of the most important technologies. Nowadays, Mobile RFID, which is often installed in carts or forklift trucks, is increasingly being applied to the search for and checkout of items in warehouses, supermarkets, libraries and other industrial fields. In using Mobile RFID, since the readers are continuously moving, they can interfere with each other when they attempt to read the tags. In this study, we suggest a Time Division Multiple Access (TDMA) based anti-collision algorithm for Mobile RFID readers. Our algorithm automatically adjusts the frame size of each reader without using manual parameters by adopting the dynamic frame size adjustment strategy when collisions occur at a reader. Through experiments on a simulated environment for Mobile RFID readers, we show that the proposed method improves the number of successful transmissions by about 228% on average, compared with Colorwave, a representative TDMA based anti-collision algorithm.

RFID applications such as monitoring an object for a long time need to identify tags repeatedly within the scope of the reader. Re-identification process can be improved using the information obtained from the previous tag identification process. Couple-resolution blocking (CRB) protocol utilizes the blocking technique that prevents staying tags from being collided by newly arriving tags. Staying tags can be efficiently re-identified by utilizing the retained information. After staying tags are separately all identified, arriving tags are identified. In this paper, we argue that CRB may work more poorly than other protocols which do not consider the repeated tag identification, such as query tree (QT) and collision tree (CT) protocol, when only few tags stay. To tackle the problem, we propose an adaptive CRB (ACRB) protocol. In ACRB, the reader estimates the tag staying ratio during the re-identification process for staying tags. If the estimated ratio is lower than a certain threshold, the blocking technique is immediately abandoned. Instead, staying tags and arriving tags are identified together without considering the retained information. In addition, we propose to improve CRB further using CT protocol, instead of QT protocol. Through computer simulation, we show that ACRB improves the identification efficiency of CRB, especially when the tag staying ratio is low. [ABSTRACT FROM AUTHOR]

In order to further improve the identification speed of the tag, we propose a new anti-collision algorithm, called double idle factors parameter (DIFP) based on several typical dynamic frame slot aloha (DFSA) algorithms. The idea of the algorithm, the process of operation and determination of key parameters are elaborated in this paper. In this algorithm, the idle slots cannot only be detected but largely reduced through slot scanning. Meanwhile the collided tags can be immediately processed based on idle ratio as well to avoid multiple operations for tag collision. Simulation results show that compared with the standard QA algorithm, the proposed algorithm can decrease identification delay by 19% and increase identification speed by 10%. [ABSTRACT FROM AUTHOR]

The PS algorithm divides the number of tags within the identification range of reader into smaller groups by increasing the transmission power incrementally and identifies them. It limits the number of responding tags by grouping the tags within the identification range of the reader, and thus can reduce the probability of tag collision. Also, in the PS algorithm, the reader takes advantages of the difference of identification ranges. This algorithm uses the fixed frame size at every scan. Therefore, it has problems that the performance can be shown variously according to the number of tags and frame size. In this paper, we propose an EPS algorithm that allocates the optimal frame size by estimating the number of tags at each scan, and apply it into the STAC protocol. The simulation results showed that STAC/EPS algorithm can improve the identification delay about 45% compared with STAC protocol. Also, it provides a stable identification delay regardless of power level increase. [ABSTRACT FROM AUTHOR]

Aiming at solving the problem of tag collision in radio frequency identification ( RFID) system , this paper proposed a lock-bit adjustive multi-tree anti-collision algorithm. The new algorithm used the basic principle of adjustive anti-collision algorithm, taking advantage of the features of Manchester encoding, sent lock-hit instructions to determine the information of the collision bit and extracts collision bit, and the non-collision bit infonnation is no longer transmitted in subsequent tag identification, combined with idea of automatic recognition, in reducing collision slots, wiiile reducing the amount of data transmission. The newr algorithm fully considered three important performance parameters of the total timeslots, throughput and communication complexity. Theoretical analysis and computer simulations showr that the newr algorithm has higher throughput and search efficiency, which can further improve the performance of RFID system. [ABSTRACT FROM AUTHOR]

Copyright of Journal of the Tianjin Polytechnic University / Tianjin Gongye Daxue Xuebao is the property of Journal of Tianjin Polytechnic University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For ultra high frequency (UHF) radio frequency signals in the frequency range of 860-960 MHz, a novel RFID system anti-collision algorithm based on ICA and framed-slot is proposed. When the framed-slot number is rationally chosen, each slot contains tags less than or equal to its antenna number, thus several tags can be identified simultaneously by using ICA algorithm. Simulation results show that the tag identification rate of the proposed algorithm is obviously higher than that of the traditional anti-collision algorithms and the blind separation and dynamic bit-slot grouping anti-collision (BSDBG) algorithm. As antenna number increases, the tag identification time of the proposed algorithm is much less than that of the BSDBG algorithm. The algorithm further validates the feasibility and efficiency of the blind sources separation technology for tag identification. And it has potential application value in the engineering fields that require high efficient and intelligent management. [ABSTRACT FROM AUTHOR]