Goodbye, ALOHA!

©2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The vision of the Internet of Things (IoT) to interconnect and Internet-connect everyday people, objects, and machines poses new challenges in the design of wireless communication networks. The design of medium access control (MAC) protocols has been traditionally an intense area of research due to their high impact on the overall performance of wireless communications. The majority of research activities in this field deal with different variations of protocols somehow based on ALOHA, either with or without listen before talk, i.e., carrier sensing multiple access. These protocols operate well under low traffic loads and low number of simultaneous devices. However, they suffer from congestion as the traffic load and the number of devices increase. For this reason, unless revisited, the MAC layer can become a bottleneck for the success of the IoT. In this paper, we provide an overview of the existing MAC solutions for the IoT, describing current limitations and envisioned challenges for the near future. Motivated by those, we identify a family of simple algorithms based on distributed queueing (DQ), which can operate for an infinite number of devices generating any traffic load and pattern. A description of the DQ mechanism is provided and most relevant existing studies of DQ applied in different scenarios are described in this paper. In addition, we provide a novel performance evaluation of DQ when applied for the IoT. Finally, a description of the very first demo of DQ for its use in the IoT is also included in this paper.Peer ReviewedPostprint (author's final draft

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

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

Simulation on probabilistic anti collision protocols of RFID using variable delay

In RFID System, it is important to avoid tag collision for identifying tag faster. In this paper, we proposed concept of variable delay for tag estimation & identification. The scheme is based on the Multi-level dynamic framed ALOHA protocol. Simulation results indicate that the time delay is added to each tag for avoiding collision. The main advantage of this is the delay is in microseconds which will not create problem of more time consumption

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

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 aware improved least and most significant bit arbitration algorithm for WORM tags

AbstractPassive Radio Frequency Identification systems have gained enormous attention and popularity especially after its adoption in time and data critical systems. Theoretically, these systems have the potential to read over 100 tags per second in applications which are well insulated from RF noise. Nevertheless, this may not be the case in practical systems, as tag collision is one of the major deterrents affecting the recognition rate. This paper exhaustively analyses the existing probabilistic, deterministic and hybrid algorithms on collision resolutions. In probabilistic algorithms, tags send their entire ID to the RFID reader in respective slots while tags in deterministic algorithms respond bit by bit based on the RFID reader’s query. To minimize identification delay, tag communication overhead and high energy consumption, a new energy efficient collision resolution strategy named Improved Least and Most Significant Bit Algorithm (LaMSBA) is introduced to effectively singulate a tag and increase the identification efficiency in changing tag population even when the bits in tag ID’s are randomly or uniformly distributed. Extensive simulation studies show that LaMSBA can be chosen as better alternatives for dense time and data critical RFID enabled systems. In addition, M/G/1 Queuing model is suitably identified and the the analytical results concluded that LaMSBA is able to maintain the steady state condition even when Class 1 tags arrive at the rate of 15 tags/second in the reader’s interrogation zone

Energy efficient tag identification algorithms for RFID: survey, motivation and new design

RFID is widely applied in massive tag based applications, thus effective anti-collision algorithms to reduce communication overhead are of great importance to RFID in achieving energy and time efficiency. Existing MAC algorithms are primarily focusing on improving system throughput or reducing total identification time. However, with the advancement of embedded systems and mobile applications, the energy consumption aspect is increasingly important and should be considered in the new design. In this article, we start with a comprehensive review and analysis of the state-of-the-art anti-collision algorithms. Based on our existing works, we further discuss a novel design of anti-collision algorithm and show its effectiveness in achieving energy efficiency for the RFID system using EPCglobal C1 Gen2 UHF standard