308 research outputs found

    LPDQ: a self-scheduled TDMA MAC protocol for one-hop dynamic lowpower wireless networks

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    Current Medium Access Control (MAC) protocols for data collection scenarios with a large number of nodes that generate bursty traffic are based on Low-Power Listening (LPL) for network synchronization and Frame Slotted ALOHA (FSA) as the channel access mechanism. However, FSA has an efficiency bounded to 36.8% due to contention effects, which reduces packet throughput and increases energy consumption. In this paper, we target such scenarios by presenting Low-Power Distributed Queuing (LPDQ), a highly efficient and low-power MAC protocol. LPDQ is able to self-schedule data transmissions, acting as a FSA MAC under light traffic and seamlessly converging to a Time Division Multiple Access (TDMA) MAC under congestion. The paper presents the design principles and the implementation details of LPDQ using low-power commercial radio transceivers. Experiments demonstrate an efficiency close to 99% that is independent of the number of nodes and is fair in terms of resource allocation.Peer ReviewedPostprint (author’s final draft

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

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    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

    Energy efficient anti-collision algorithm for the RFID networks

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    Energy efficiency is crucial for radio frequency identification (RFID) systems as the readers are often battery operated. The main source of the energy wastage is the collision which happens when tags access the communication medium at the same time. Thus, an efficient anti-collision protocol could minimize the energy wastage and prolong the lifetime of the RFID systems. In this regard, EPCGlobal-Class1-Generation2 (EPC-C1G2) protocol is currently being used in the commercial RFID readers to provide fast tag identification through efficient collision arbitration using the Q algorithm. However, this protocol requires a lot of control message overheads for its operation. Thus, a reinforcement learning based anti-collision protocol (RL-DFSA) is proposed to provide better time system efficiency while being energy efficient through the minimization of control message overheads. The proposed RL-DFSA was evaluated through extensive simulations and compared with the variants of EPC-Class 1 Generation 2 algorithms that are currently being used in the commercial readers. The results show conclusively that the proposed RL-DFSA performs identically to the very efficient EPC-C1G2 protocol in terms of time system efficiency but readily outperforms the compared protocol in the number of control message overhead required for the operation

    Frame Size Analysis of Optimum Dynamic Tree in RFID Systems

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    In RFID (Radio Frequency Identification) system, an anti-collision algorithm plays a prominent role in the tag identification process in order to reduce the tag identification delay and enhance the RFID system efficiency. In this work, we present a theoretical analysis of optimal frame size assignment for maximizing the system efficiency of a tree-based anti-collision algorithm, called optimum dynamic tree (ODT) algorithm, for RFID tag identification process. Our analysis indicates that the appropriate frame size for a given number of competing tags should not be set to the same value as the number of tags, which is commonly adopted in the literature. Instead, the frame size should be smaller roughly by a factor of 0.871 to maximize system efficiency. The closed-form for calculating system efficiency is derived and the derived simulation results are in a good agreement with the theoretical one. The exact appropriate frame sizes for the number of tags ranging from 2 to 100 are tabulated and compare the tag-identification time of conventional binary tree and ODT algorithms by using the international standard ISO 18000-6B

    Anti-Collision Algorithms for Multi-Tag RFID

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    The application of Radio Frequency Identification (RFID) in speeding up the flow of materials in an industrial manufacturing process

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    Published ArticleRFID can work in conjunction with sensors in material handling especially on a conveyor belt. A dozen different graded tagged products can be picked up by the RFID system in real-time and transported to respective chutes into automatic guided vehicles (AGV) for transportation to specific storage locations. The development of this system is now at an advanced stage. Our predictions to date show that the application of RFID in material handling in a manufacturing environment can assist in the fast flow of components throughout the assembly line beyond what available systems can do
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