DADC: A Novel Duty-cycling Scheme for IEEE 802.15.4 Cluster-tree-based IoT Applications

The IEEE 802.15.4 standard is one of the widely adopted specifications for realizing different applications of the Internet of Things. It defines several physical layer options and Medium Access Control (MAC) sub-layer for devices with low-power operating at low data rates. As devices implementing this standard are primarily battery-powered, minimizing their power consumption is a significant concern. Duty-cycling is one such power conserving mechanism that allows a device to schedule its active and inactive radio periods effectively, thus preventing energy drain due to idle listening. The standard specifies two parameters, beacon order and superframe order, which define the active and inactive period of a device. However, it does not specify a duty-cycling scheme to adapt these parameters for varying network conditions. Existing works in this direction are either based on superframe occupation ratio or buffer/queue length of devices. In this article, the particular limitations of both the approaches mentioned above are presented. Later, a novel duty-cycling mechanism based on MAC parameters is proposed. Also, we analyze the role of synchronization schemes in achieving efficient duty-cycles in synchronized cluster-tree network topologies. A Markov model has also been developed for the MAC protocol to estimate the delay and energy consumption during frame transmission.

Researching, building the routing algorithm in Zigbee networks

Zigbee wireless network built on IEEE 802.15.4 standard is becoming one of the most popular wireless networks in modern IoT devices. One of the disadvantages of Zigbee networks is the short transmission distance between devices. This paper focuses on researching and comparing routing algorithms in Zigbee networks, thereby building the optimal routing algorithm in the existing system. The paper’s objective is to form the basis for making Zigbee tree and mesh networks, which improves the transmission distance for Zigbee networks better than the star network.

Implementation and evaluation of a 2.4 GHz multi-hop WSN: LoS, NLoS, different floors, and outdoor-to-indoor communications

In this paper, the communication reliability of a 2.4 GHz multi-hop wireless sensor network (WSN) in various test scenarios is evaluated through experiments. First, we implement an autonomous communication procedure for a multi-hop WSN on Tmote sky sensor nodes; 2.4 GHz, an IEEE 802.15.4 standard. Here, all nodes including a transmitter node (Tx), forwarder nodes (Fw), and a base station node (BS) can automatically work for transmitting and receiving data. The experiments have been tested in different scenarios including: i) in a room, ii) line-of-sight (LoS) communications on the 2nd floor of a building, iii) LoS and non-line-of-sight (NLoS) communications on the 1st floor to the 2nd floor, iv) LoS and NLoS communications from outdoor to the 1st and the 2nd floors of the building. The experimental results demonstrate that the communication reliability indicated by the packet delivery ratio (PDR) can vary from 99.89% in the case of i) to 14.40% in the case of iv), respectively. Here, the experiments reveal that multi-hop wireless commutations for outdoor to indoor with different floors and NLoS largely affect the PDR results, where the PDR more decreases from the best case (i.e., the case of a)) by 85.49%. Our research methodology and findings can be useful for users and researchers to carefully consider and deploy an efficient 2.4 GHz multi-hop WSN in their works, since different WSN applications require different communication reliability level.

Potential Security Vulnerabilities of the IEEE 802.15.4 Standard and a Proposed Solution Against the Dissociation Process

Many different networks that rely on short-distance wireless technology for their functions utilize the IEEE 802.15.4 Standard, especially in the case of systems that experience a low level of traffic. The networks using this standard are typically based on the Low-Rate Wireless Personal Area Network, herein called the LR-WPAN; this network is used for the provision of both the physical layer, herein referred to as the PHY, and the media access control, herein abbreviated as the MAC. There are four security features in the IEEE 802.15.4 Standard that are designed to ensure the safe and secure transmission of data through the network. Disconnection from the network is managed and controlled by the message authentication code, herein referred to as the MAC, while the coordinator personal area network, herein abbreviated as the PAN, is also able to trigger the disconnection. However, the process of disconnection from the network is one area of vulnerability to denial-of-service attacks, herein referred to as DoS; this highlights a major shortcoming of the IEEE 802.15.4 Standard’s security features. This paper is intended to contribute to the improvement of security for the IEEE network by conducting a specific and in-depth review of available literature as well as conducting an analysis of the disassociation process. In doing so, potential new threats will be highlighted, and this data can be used to improve the security of the IEEE 802.15.4 Standard. Overall, in this paper, the role of the Castalia tool in the OMNET++ environment is analysed and interpreted for these potential new threats. Also, this paper proposes a solution to such threats to improve the security IEEE 802.15.4 disassociation process. Keywords: Disassociation vulnerability of IEEE 802.15.4 Standard, DoS attack, IoT security.

TSCH Evaluation under Heterogeneous Mobile Scenarios

Time Slotted Channel Hopping (TSCH) is a medium access protocol defined in the IEEE 802.15.4 standard. It has proven to be one of the most reliable options when it comes to industrial applications. TSCH offers a degree of high flexibility and can be tailored to the requirements of specific applications. Several performance aspects of TSCH have been investigated so far, such as the energy consumption, reliability, scalability and many more. However, mobility in TSCH networks remains an aspect that has not been thoroughly explored. In this paper, we examine how TSCH performs under mobility situations. We define two mobile scenarios: one where autonomous agriculture vehicles move on a predefined trail, and a warehouse logistics scenario, where autonomous robots/vehicles and workers move randomly. We examine how different TSCH scheduling approaches perform on these mobility patterns and when a different number of nodes are operating. The results show that the current TSCH scheduling approaches are not able to handle mobile scenarios efficiently. Moreover, the results provide insights on how TSCH scheduling can be improved for mobile applications.

A Novel Energy-Safe Algorithm for Enhancing the Battery Life for IoT Sensors’ Applications

Energy safe is mandatory for all isolated IoT tools, such as in long way roads, mountains, or even in smart cities. If increasing the lifetime of these tools, the rentability of the global network loop becomes more efficient. Therefore, this paper presents a new approach for saving energy inside the source nodes by supervising the state of energy inside each source node and calculating the duty cycle factor. The relationship between these parameters is based on an optimization problem formulation. In this respect, the present paper is designed to propose a new approach that deals with increasing the lifetime of the wireless sensor network (WSN)-attached nodes, as fixed in the application. The newly devised design is based on implementing the IEEE 802.15.4 standard beacon-enabled mode, involving a cluster tree topology. Accordingly, every subgroup is allotted to apply a specifically different duty cycle, depending on the battery’s remaining energy level, which contributes to creating a wide range of functional modes. Hence, various thresholds are defined. Simulation results prove the efficiency of the proposed approach and show the energetic benefit. The proposed flowchart has minimized the consumed energy for the WSN, which improves the battery lifetime and enhances the IoT application’s robustness. Simulations and experiments have been carried out under different conditions and the results prove that the proposed method is a viable solution.

Identifying Misbehaving Greedy Nodes in IoT Networks

One of the central communication infrastructures of the Internet of Things (IoT) is the IEEE 802.15.4 standard, which defines Low Rate Wireless Personal Area Networks (LR- WPAN). In order to share the medium fairly in a non-beacon-enabled mode, the standard uses Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). The nature of connected objects with respect to various resource constraints makes them vulnerable to cyber attacks. One of the most aggressive DoS attacks is the greedy behaviour attack which aims to deprive legitimate nodes to access to the communication medium. The greedy or selfish node may violate the proper use of the CSMA/CA protocol, by tampering its parameters, in order to take as much bandwidth as possible on the network, and then monopolize access to the medium by depriving legitimate nodes of communication. Based on the analysis of the difference between parameters of greedy and legitimate nodes, we propose a method based on the threshold mechanism to identify greedy nodes. The simulation results show that the proposed mechanism provides a detection efficiency of 99.5%.

The Integration Of IEEE 802.11 (WLAN) With RFID Systems in ISM (2.45 GHz) Frequency Band Environment Using Framed Slotted ALOHA And IEEE 802.15.4

In this thesis, we attempt to solve the problem of WLAN/RFID coexistence and integration in frequency band of GHz or ISM band. Our solution to this problem is to allow the WLAN access and RFID access in a time-sharing manner by making the WLAN Access Point aware of the RFID neighbor-network at MAC layer. The time-sharing function is implemented using IEEE 802.11 PCF mechanism. RFID network is implemented using two different standards. The first one is Framed Slotted Aloha standard and the second one is IEEE 802.15.4 standard. We have simulated both models using Artifex simulator and compared their performance using some performance metrics like collision probability and average number of collision in each superframe. It is shown that IEEE 802.15.4 based model outperforms the Framed Slotted Aloha based model.

The Integration Of IEEE 802.11 (WLAN) With RFID Systems in ISM (2.45 GHz) Frequency Band Environment Using Framed Slotted ALOHA And IEEE 802.15.4

In this thesis, we attempt to solve the problem of WLAN/RFID coexistence and integration in frequency band of GHz or ISM band. Our solution to this problem is to allow the WLAN access and RFID access in a time-sharing manner by making the WLAN Access Point aware of the RFID neighbor-network at MAC layer. The time-sharing function is implemented using IEEE 802.11 PCF mechanism. RFID network is implemented using two different standards. The first one is Framed Slotted Aloha standard and the second one is IEEE 802.15.4 standard. We have simulated both models using Artifex simulator and compared their performance using some performance metrics like collision probability and average number of collision in each superframe. It is shown that IEEE 802.15.4 based model outperforms the Framed Slotted Aloha based model.

Machine Learning in Wireless Sensor Networks for Smart Cities: A Survey

Artificial intelligence (AI) and machine learning (ML) techniques have huge potential to efficiently manage the automated operation of the internet of things (IoT) nodes deployed in smart cities. In smart cities, the major IoT applications are smart traffic monitoring, smart waste management, smart buildings and patient healthcare monitoring. The small size IoT nodes based on low power Bluetooth (IEEE 802.15.1) standard and wireless sensor networks (WSN) (IEEE 802.15.4) standard are generally used for transmission of data to a remote location using gateways. The WSN based IoT (WSN-IoT) design problems include network coverage and connectivity issues, energy consumption, bandwidth requirement, network lifetime maximization, communication protocols and state of the art infrastructure. In this paper, the authors propose machine learning methods as an optimization tool for regular WSN-IoT nodes deployed in smart city applications. As per the author’s knowledge, this is the first in-depth literature survey of all ML techniques in the field of low power consumption WSN-IoT for smart cities. The results of this unique survey article show that the supervised learning algorithms have been most widely used (61%) as compared to reinforcement learning (27%) and unsupervised learning (12%) for smart city applications.