On the Design of Multi-Hop Tag-to-Tag Routing Protocol for Large-Scale Networks of Passive Tags

Abstract

Recently, tag-to-tag (T2T) backscattering technique in a passive RFID system has received broad attention due to its superiority for large-scale network applications. If used to implement a Network of Tags, use of T2T communication allows inherent communication parallelism, thus supporting orders of magnitude larger capacity than centralized RFID reader-based systems. To unleash the potential of T2T communication, turbo backscattering operation enables the implementation of a multihop network of tags, which supports larger network coverage of a Network of Tags. However, due to asymmetric communication links and interferences among tags' transmissions in such a T2T backscattering based network, the routing protocol design has become one of the main technical challenges, especially for large-scale networks. Furthermore, the computation time of T2T routing protocols increases exponentially with the number of tags, greatly limiting the practicability of such large-scale backscattering networks. In this paper, we present the design of a Network of Tags model to address these challenges, and we propose novel routing protocols for three distinct types of tags with different hardware capabilities. To address the issue of computational processing time of the routing protocol for large-scale T2T networks, we propose a new scheme with linear time complexity. We evaluate and compare the performance of the proposed protocols, as well as investigate the impact of network parameters on the performance. Keywords-backscattering communications; Internet of Things; large-scale networks; multi-hop routing protocol; Network of Tags; RFID passive tag; tag-to-tag communication I. INTRODUCTIONOWADAYS, RFID systems have become increasingly prevalent, and it is predicted that in the future massively deployed IoT objects will be tagged for communication and control for various applications such as e-Health, Smart Cities, Smart Spaces, and Intelligent Transportation Systems. A typical RFID system, which consists of an RFID reader and a number of tags, has become one of the most widely used systems to facilitate automatic object identification ([1]). Each tag is uniquely differentiated through its identification code, which can be recognized by the reader. RFID tags fall mainly into three categories: active, passive, and semi-passive tags. As the names imply, passive tags are solely powered by RF radiation of a reader. A typical passive RFID link between a tag and the reader operates through an interrogation process: when a passive RFID tag receives an activation signal from the reader, the signal energizes the circuits of its RFID chip, and the tag responds to the reader by backscattering the received waveform signal from the reader. What differentiates passive tags from active tags is that passive tags have neither significant energy storage nor traditional transmitters. Thus, they have advantages such as lower cost, smaller dimensions, physical flexibility, longer lifetime, environmental safety, and no need for power sources ([2]).Direct ...

An IPv6 Passive‐Aware Network Routing Algorithm Based on Utility Value Combined with Deep Neural Network

“…In order to verify the effectiveness of the trained model in node routing, we use the trained model and other algorithms to compare the total energy consumption of routing transmission and the total end-to-end trans-mission delay. The comparison algorithms are the passive network multipath routing proposed in the literature [15] (here, we abbreviate it as PNMR for the convenience of expression) and the passive label network multihop routing protocol proposed in the literature [16] (here for the convenience of expression, we referred to it as PTNMT) for comparison. Among them, literature [15] conducts network multipath routing detection from link average delay and load balancing, and literature [16] considers the problems of asymmetry of communication links and transmission interference in passive sensing networks.…”

Backscatter communications with passive receivers: from fundamentals to applications

“…The challenges of designing routing and MAC protocols for BTTN arise from the unique characteristics of the backscattering environment, including the extreme lowpower operation and from the intended BTTN applica-tions [21]. In this section, we discuss these challenges and propose some solutions that have been considered in this field.…”

“…Interference is generally not a problem in sparse networks or networks with infrequent communications among the network nodes. But in the envisioned applications of BTTN ( [21]), such as those for densely deployed IoT systems, even a simple query might cause at least some message flooding among the tags, significantly affecting the throughput of big portions of the network. This problem is further intensified in real-time IoT applications.…”

“…Furthermore, in the case of a zero-intelligence exciter, distributed processing is especially a challenge, since the BTTN tags operate at extremely low energy levels, significantly limiting their processing capabilities. Depending on the limited processing capabilities of the tags and their extreme lowpower operation, there is a need for new approaches to design very simple MAC and routing protocols [20,21], such as by trading the protocols' performance for processing complexity.…”

“…In applications such as IoT, the network of tags should facilitate interactions among smart objects, each tagged with a passive tag that stores information about the object, such as the object's identity, its capabilities, attributes, and past history of interactions with other objects. As an example, if the BTTN is designed to track infectious contacts among individuals, as to alert them of possible infection ( [21]), the lists of contacts need to be stored and maintained in the tags. Routing among such passive tags, each being associated with a particular object, requires creation of a suitable routing infrastructure and appropriate protocols.…”