Binary Tree Protocol Research Articles

A High Throughput Anticollision Protocol to Decrease the Energy Consumption in a Passive RFID System

One of the main existing problems in Radio Frequency Identification (RFID) technology is the tag collision problem. When several tags try to respond to the reader under the coverage of the same reader antenna their messages collide, degrading bandwidth and increasing the number of transmitted bits. An anticollision protocol, based on the classical Binary Tree (BT) protocol, with the ability to decrease the number of bits transmitted by the reader and the tags, is proposed here. Simulations results show that the proposed protocol increases the throughput with respect to other recent state-of-the-art protocols while keeping a low energy consumption of a passive RFID system.

Optimal Slot Assignment for Binary Tracking Tree Protocol in RFID Tag Identification

Tag anti-collision has long been an important issue in RFID systems. To accelerate tag identification, some researchers have recently adopted bit tracking technology that allows the reader to detect the locations of collided bits in a collision slot. However, these methods still encounter the problem of too many collisions occurring at the beginning of identification. This paper proposes an optimal binary tracking tree protocol (OBTT) that tries to separate all of the tags into smaller sets to reduce collisions at the beginning of identification. Using bit tracking technology, OBTT mainly adopts three proposed approaches, bit estimation, optimal partition, and binary tracking tree. Bit estimation first estimates the number of tags based on the locations of collided bits. Optimal partition then determines the optimal number of the initial sets based on this estimation. Binary tracking tree lets the tag utilize one counter to achieve the split during the identification process. This paper formally analyzes the slot efficiency of OBTT, which represents how many tags can be identified in a slot. Results show that the slot efficiency is close to 0.614, the highest value published to date. Considering slot lengths, OBTT further determines the optimal number of the initial sets to minimize the identification delay. The analytical results show that the delay efficiency of OBTT achieves 0.750, where delay efficiency represents the number of tags that can be identified in a baseline slot, the length of which is the complete ID sent by the tag. The simulation results show that OBTT outperforms other existing algorithms.

Parallel Response Ternary Query Tree for RFID Tag Anti-Collision

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.

A memoryless binary query tree based Successive Scheme for passive RFID tag collision resolution

The deployments of RFID system are seriously affected by collision caused by multiple tags responding simultaneously. To facilitate the resolution of collisions caused by densely distributed memoryless passive tags in successive cycles, based on the binary query tree protocol, this paper proposes a new Successive Scheme. In this scheme, the binary query tree constructed by the protocol will be reused. In the subsequent cycle, only the successful or idle binary query strings in the tree are adopted directly as the initial binary query strings, and these collision query strings in the tree are skipped. Due to the dynamic entrance and departure of tags, new nodes will be added to and abundant nodes will be removed from the tree. The performance of this Successive Scheme will be analyzed theoretically and examined with numeric simulations. Results indicate that in almost all cases, the Successive Scheme outperforms the commonly used binary query tree protocols in terms of system efficiency, message complexity, time, and time system efficiency. Especially when the tags stay stable, the system efficiency of the scheme is improved to 69.2%. Besides, simulation results also reveal that the scheme can deal efficiently with the case that the binary tag identifiers are in biased distribution.

Error Resilient Estimation and Adaptive Binary Selection for Fast and Reliable Identification of RFID Tags in Error-Prone Channel

In RFID systems, far field passive tags send information using back scattering. The signal level is typically very small, so channel error during transmission may occur frequently. Due to channel error, performance of RFID tag identification under error-prone channel is degraded compared to that under error-free channel. In this paper, we propose a novel error resilient estimation and adaptive binary selection to overcome the problem of channel errors. Our proposed error resilient estimation algorithm can estimate the number of tags and the channel state accurately regardless of frame errors. And our proposed adaptive binary selection reduces the idle slots caused by frame errors. Performance analysis and simulation results show that the proposed algorithm consumes up to 20 percent less time slots than the binary tree protocol and dynamic framed slotted ALOHA (DFSA) in various packet error rate (PER) conditions.

Evaluating the energy consumption of the RFID tag collision resolution protocols

RFID technology acts as a bridge to connect the physical world with the digital space, and RFID system is pervading our daily life in the last few years. The energy consumed by the reader and a tag in resolving the collisions caused by multiple tags is a key issue that affects life time of mobile reader and active tags, as well as the identification accuracy of passive tags. In this paper, the energy consumed by the reader and a tag in resolving the tag collision is examined for the commonly used RFID tag collision resolution protocols, including the frame slotted ALOHA based and the binary query tree based protocols. Numeric evaluation is also performed and the result verifies that regarding to energy consumption, the dynamic frame slotted ALOHA protocol for the Class-1 RFID system performs best among the frame slotted ALOHA protocols, and the modified binary query tree protocol also performs better than the standard binary query tree protocols.

General binary tree protocol for coping with the capture effect in RFID tag identification

Tag anti-collision is an important issue in RFID systems because the reader must recognize all tags efficiently. In RFID wireless communication systems, tag identification will encounter the capture effect, where a reader decodes a tag ID even when multiple tags simultaneously transmit their signals. This letter proposes a tag anti-collision algorithm - the generalized binary tree protocol (GBT). GBT separates the identification process into several binary tree (BT) cycles to solve the problem caused by the capture effect. Unrecognized tags, hidden by the capture effect in a BT cycle, will be identified in subsequent cycles. The formal analysis of identification delay for GBT is derived and simulation and analytical results show that GBT significantly outperforms other existing algorithms.

Tag-Splitting: Adaptive Collision Arbitration Protocols for RFID Tag Identification

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

Tag-Splitting: Adaptive Collision Arbitration Protocols for RFID Tag Identification

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

Identification of RFID Tags in Framed-Slotted ALOHA with Robust Estimation and Binary Selection

In RFID systems, tag collision resolution is significantly important for fast tag identification. In this letter, we propose an accurate and robust tag estimation method and an effective tag anti-collision protocol. Performance analysis and simulation results show that the proposed estimation and anti-collision algorithm consumes 10-15% less time slots than the binary tree protocol and dynamic framed slotted ALOHA (DFSA). The proposed algorithm has also tolerance to the inaccuracy of tag estimation

Adaptive Binary Splitting: A RFID Tag Collision Arbitration Protocol for Tag Identification

In the RFID system, a reader recognizes tags through communications over a shared wireless channel. When multiple tags transmit their IDs at the same time, the tag-to-reader signals lead to collision. Tag collision arbitration for passive RFID tags is significant for fast identification since collisions disturb the reader's identification process. This paper presents an Adaptive Binary Splitting (ABS) protocol which is an improvement on the binary tree protocol. To reduce collisions and identify tags efficiently, ABS uses information which is obtained from the last processes of tag identification. Our performance evaluation shows that ABS outperforms other tree based tag anti-collision protocols.

Collision resolution algorithm for M-priority users

The authors propose and analyse a collision resolution algorithm (CRA) with M (≥2) priority classes in random access communication systems. When it is applied to the clipped binary-tree protocol, it is stable if the total traffic is below 0.473 packets per slot regardless of the value of M. Its maximum throughput is higher than those obtained previously. When the algorithm is applied to the tree protocol with collision detection (Tree/CD) where the length of a packet is longer than one slot, the throughput performance can be enhanced by as much as one. Using the modified M/D/1 priority queueing model, the delay characteristic is evaluated and confirmed by simulations. The proposed priority CRA has advantages in the capability of supporting various priority traffics with high throughput.

Throughput analysis of Tree‐Type protocols

AbstractTree‐type protocols achieve stable throughput even under heavy channel traffic compared with random access protocols such as the ALOHA types which show bistable behavior. Various binary tree‐type protocols have been studied extensively for channel stability and the improvement of throughput performance. In this paper, closed‐form solutions of the collision resolution time of several d‐ary tree type protocols are obtained, and the effect of the degree value of their protocols on the throughput performance is discussed. As d‐ary tree‐type protocols, we consider the tree protocol, improved tree protocol, adaptive tree protocol and tree protocol with control mini‐slot, and compare their performance. Further, by comparing the stability of the binary tree protocol with that of three ALOHA schemes with different backoff algorithms, we show that the binary tree protocol exhibits very stable behavior even for a heavy traffic load.