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Wireless Sensor Networks have become a key enabler for Industrial Internet of Things (IoT) applications; however, to adapt to the derived robust communication requirements, deterministic and scheduled medium access should be used, along with other features, such as channel hopping and frequency diversity. Implementing these mechanisms requires a co...
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... simulations have been carried out for this purpose using the Cooja simulator that is included in the Contiki OS, which allows us to compare the operation of different parameter configurations. A network that is formed by a grid of 16 nodes has been defined, in which only one of them takes on the role of coordinator (node 1 in Figure 6). This node, which is located in the upper left corner, is responsible for initiating the synchronization process by disseminating the EBs and RPL control messages. ...
Context 2
... simulations have been carried out for this purpose using the Cooja simulator that is included in the Contiki OS, which allows us to compare the operation of different parameter configurations. A network that is formed by a grid of 16 nodes has been defined, in which only one of them takes on the role of coordinator (node 1 in Figure 6). This node, which is located in the upper left corner, is responsible for initiating the synchronization process by disseminating the EBs and RPL control messages. ...
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... articles have addressed the issue of scalability by increasing the number of advertiser nodes [21,24,28,29]. However, for a topology in which the nodes are evenly distributed, such as the grid shown in Figure 6, the maximum number of neighbours of a node sending EB messages remains constant and the probability of success is not affected by the quality difference between the links, which allows us to see the improvements in the mechanism clearly. Irregular topologies have not been taken into account because these scenarios could generate nodes that are out of range and other undesirable characteristics that affect the reproducibility and usefulness of the results. ...
Context 4
... articles have addressed the issue of scalability by increasing the number of advertiser nodes [21,24,28,29]. However, for a topology in which the nodes are evenly distributed, such as the grid shown in Figure 6, the maximum number of neighbours of a node sending EB messages remains constant and the probability of success is not affected by the quality difference between the links, which allows us to see the improvements in the mechanism clearly. Irregular topologies have not been taken into account because these scenarios could generate nodes that are out of range and other undesirable characteristics that affect the reproducibility and usefulness of the results. ...
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Citations
... Implementing these techniques needs synchronization of all devices in the network. Thus, the authors in (Vera-Pérez et al., 2018) attempted to find a new beacon advertising mechanism depending on the trickle algorithm for the MAC TSCH layer and the timers in the network and network layers. The new solution combines IEEE802.15.4e with its TSCH modes and RPL. ...
In the course of time, the Internet of Things (IoT) has attracted significant research interest. However, IoT devices have limited resources available in terms of battery power, processing capacity, memory, bandwidth, etc. In an attempt to provide connectivity and Internet Protocol version 6 (IPv6) support to IoT devices, the IPv6 routing protocol for Low-Power and Lossy Networks (RPL) was officially launched as the standard routing protocol for IoT in 2012. Despite being reputed and used in diverse applications, several recent studies have revealed RPL's drawbacks and limitations. The main objective of this work is to help the IoT research community understand all aspects of RPL. The paper also provides a detailed description of the operation of the RPL protocol. What is more, this work includes novel and thorough examples, thereby gaining practical knowledge of the pros and cons of this protocol. In addition, this paper reviews and summarizes relevant RPL-based protocols and conducts comprehensive comparisons among them from the perspectives of reliability, robustness, energy efficiency, and flexibility. Technically speaking, after studying and reviewing the majority of the proposed RPL solutions, we are ultimately capable, in this work, of highlighting all the challenges faced by IoT researchers while enhancing RPL and providing what is expected to be dealt with professionally. The present work also gives more details about RPL simulation platforms and RPL applications. Not only to this extent, but rather the historical bibliometric analysis of RPL, which shows the trends in the area of research to be focused on, has been professionally analyzed based on RPL challenges over the years 2010 and 2021. To this end, the conclusions and recommendations of this study are presented along with the effective directions for future RPL, and their applicability. As a result, the authors believe that this work will be a valuable reference for all RPL researchers and designers.
... Thus, collisions that occur in CSMA when multiple nodes transmit at similar time instants are avoided. In addition, TSCH uses multiple channels, which allows frequency hopping for each transmission, reducing interference and path fading [21]. Scalability in TSCH is an understudied topic that is not directly addressed in the current literature [22], probably due to its industrial approach in which the number of nodes has been more limited. ...
Industry 4.0 digitization requirements have led to widespread adoption of industrial wireless sensor networks (IWSNs) in manufacturing environments. These require strict control of the traffic flowing over the network to ensure the quality of service. Software-defined networks (SDNs) can address this challenge, as their centralized operation allows routing and media access control (MAC) protocols to be optimized. In addition, in many cases a massive deployment of metering devices is necessary, therefore the network must be scalable, to allow an increase in the number and density of nodes in the network. This implies an increase in the control traffic required by SDNs, generating a significant reduction in the throughput available for data. This is because the length of the timeslot limits the throughput of the network in protocols that uses time division, such as the Time Slotted Channel Hopping (TSCH), conditioning the number of nodes that the network can have and its data sending rate. In this paper, we propose to exploit the integration and reconfiguration capabilities of SDN to extend the number of nodes in the network through the use of multi-radio sinks called virtual sinks, orchestrated from the SDN controller, and extending their use to multiple SD-IWSNs to take full advantage of the radio spectrum. To optimize bandwidth usage, the SDN controller will allocate network slices, allowing nodes to send data with a high frequency using dedicated channels. The results obtained show that the use of multi-radio sinks provides for increasing the maximum number of nodes that can be deployed while preserving the quality of service (QoS) requirements. A linear increase in nodes at least 0.7 times for each radio interface is obtained compared to an SD-IWSN with a traditional sink. In addition, the use of virtual sinks increases the packet frequency of the network by a factor equal to the number of radio interfaces. Moreover, the total number of nodes is improved through the coexistence of multiple SD-IWSNs, where up to 13.7 times more nodes can be scheduled using all the available spectrum orchestrated from the same SDN controller.
... Implementing these techniques needs to synchronize all devices in the network. Thus, the authors in [42] attempted to find a new beacon advertising mechanism depending on the Trickle Timer algorithm for the MAC Time-Slotted Channel Hopping (TSCH) layer and the timers in the MAC and network layers. The new solution combines IEEE802.15.4e with its TSCH modes along the RPL. ...
... This involves the joining nodes as a cooperative part of the association process. Accordingly, an active scan procedure can accelerate the network formation without affecting the energy consumption of the joining nodes because broadcasting EBRs do not lead to additional energy consumption since nodes consume less energy in TX mode than in RX mode [9]. EBR, however, had never, to our knowledge, been used in the literature. ...
... Another beacon advertising method was proposed by Vera et al. in [9]. This solution aims to manage the EB sending interval by using a custom trickle timer. ...
The Time Slotted Channel Hopping (TSCH) mode of the IEEE 802.15.4 standard is expected to revolutionize the Industrial Internet of Things. Indeed, it can achieve high reliability and deterministic latency with a very low duty cycle. Nevertheless, forming a TSCH network with the standard approach might not be as efficient, constituting, thus, one of the TSCH’s major issues. Such a network formation process relies on nodes passively scanning for advertised Enhanced Beacon (EB) frames to join the network. Doing so, a node wishing to join a TSCH network may stay awake randomly scanning for EBs for a considerable period of time, leading to a lengthy formation process with excessive energy consumption. To deal with these issues, this paper presents a practical and effective Radio duty-cycled, Active-Scan based network formation process for TSCH networks (RAST). Our proposal leans on active-scan procedures combined with radio duty cycling mechanisms to shorten joining delays and reduce energy consumption. Obtained results from extensive and realistic simulations show that our solution is efficient and outperforms state-of-the-art solutions, regarding the association time and energy consumption by up to two orders of magnitude.
... Most of these solutions assume that all of the nodes are part of the network and have discovered the optimal routes to the sink. The algorithms related to EB scheduling are generally shared cell based solutions and they assume that nodes have only omni-directional antennas [24]. 6TiSCH minimal configuration is the standard strategy for the allocation of cells for the control frame transmission [21]. ...
Steerable directional antennas are increasingly utilised to improve the overall performance of the traditional wireless sensor networks. Steerable directional antenna based networking solutions increase the network capacity by providing a longer range of transmission and reduced interference as compared to networking solutions with omni-directional antennas. However, the use of smart antennas requires complex algorithms and such algorithms may not be easily leveraged in low power Internet of Things (IoT) networks. This study presents mechanisms for integrating low complexity smart antenna solutions into IETF 6TiSCH protocol with the aim of creating scalable and reliable industrial IoT networks. The solution defines extensions to MAC layer and scheduling mechanisms of IETF 6TiSCH protocol to enable its seamless integration with low complexity steerable smart antennas. The results of this study show that smart antenna enabled 6TiSCH protocol stack outperforms the legacy 6TiSCH stack in terms of data delivery performance especially in high density scenarios.
... That helps reduce the points of interference and path fading, thus increasing reliability. The problem here is that a large number of channels (N ch ) have a longer synchronization time [9]. ...
... In this scheduling shown in Fig. 2, 5 shared slots can be seen, 1 for each node (red). In addition, multiple inputs from the Mobile node (M) at different points of the slotframe (6,9,12; green) and a single arrival timeslot at the Sink node (11; yellow). Therefore, this solution uses 5 shared slots in a slotframe of 13. ...
The growing use of mobile nodes in manufacturing environments is increasing the Quality of Service (QoS) requirements of the communications infrastructures that support them, as is the case with Industrial Wireless Sensor Networks (IWSN). Managing networks using Software Defined Networks (SDN) addresses the challenge of handling multiple sources in a satisfactory manner. The global vision of the topology that the SDN controller has allows a logical segmentation of the network, through the allocation of dedicated resources for each information flow, thus ensuring independent service levels and complete isolation. Mobile nodes produce constant changes in topology, which lead to instability for routing protocols. Traditional routing solutions with protocols such as Routing Protocol for Low-Power and Lossy Networks (RPL) require additional time to make the parent node change. This paper proposes Mobile Multicast Forwarding with Software Defined Network (MMF-SDN), an approach using Software Defined Networking solution for WIreless SEnsor Network (SDN WISE) protocol that exploits the advantages of SDN and Time Slotted Channel Hopping (TSCH) synchronism. The mobile nodes are managed as multicast sources, through a cumulative allocation of resources from the controller. This allows reception states to be synchronized at the parent nodes to provide network stability, avoiding subsequent recalculations in the routing protocol. Parent node changes are transparent and immediate. This proposal improves on other SDN based solutions, reducing energy consumption in reception by up to 50%, 70% end-to-end delay and improving scalability with a 30% reduction in slotframe occupancy.
... Most of these solutions assume that all of the nodes are part of the network and have discovered the optimal routes to the sink. The algorithms related to EB scheduling are generally shared cell based solutions and they assume that nodes have only omni-directional antennas [24]. 6TiSCH minimal configuration is the standard strategy for the allocation of cells for the control frame transmission [21]. ...
Steerable directional antennas are increasingly utilised to improve the overall performance of the traditional wireless sensor networks. Steerable directional antenna based networking solutions increase the network capacity by providing a longer range of transmission and reduced interference as compared to networking solutions with omni-directional antennas. However, the use of smart antennas requires complex algorithms and such algorithms may not be easily leveraged in low power Internet of Things (IoT) networks. This study presents mechanisms for integrating low complexity smart antenna solutions into IETF 6TiSCH protocol with the aim of creating scalable and reliable industrial IoT networks. The solution defines extensions to MAC layer and scheduling mechanisms of IETF 6TiSCH protocol to enable its seamless integration with low complexity steerable smart antennas. The results of this study show that smart antenna enabled 6TiSCH protocol stack outperforms the legacy 6TiSCH stack in terms of data delivery performance especially in high density scenarios.<br
... However, no information is given on how long the network formation takes or the energy impact cased by the increase in EB messages. The authors of [24,25] carried out a study in which they validate how the synchronization time improves in TSCH-RPL networks by using a dynamic EB transmission period, proposing a cyclic algorithm that they call Bell-X, with windows of opportunity in which the probability of a node connecting rapidly increases. ...
Wireless sensor networks (WSNs) play a key role in the ecosystem of the Industrial Internet of Things (IIoT) and the definition of today’s Industry 4.0. These WSNs have the ability to sensor large amounts of data, thanks to their easy scalability. WSNs allow the deployment of a large number of self-configuring nodes and the ability to automatically reorganize in case of any change in the topology. This huge sensorization capacity, together with its interoperability with IP-based networks, allows the systems of Industry 4.0 to be equipped with a powerful tool with which to digitalize a huge amount of variables in the different industrial processes. The IEEE 802.15.4e standard, together with the access mechanism to the Time Slotted Channel Hopping medium (TSCH) and the dynamic Routing Protocol for Low-Power and Lossy Networks (RPL), allow deployment of networks with the high levels of robustness and reliability necessary in industrial scenarios. However, these configurations have some disadvantages in the deployment and synchronization phases of the networks, since the time it takes to synchronize the nodes is penalized compared to other solutions in which access to the medium is done randomly and without channel hopping. This article proposes an analytical model to characterize the behavior of this type of network, based on TSCH and RPL during the phases of deployment along with synchronization and connection to the RPL network. Through this model, validated by simulation and real tests, it is possible to parameterize different configurations of a WSN network based on TSCH and RPL.
... This might become a serious problem knowing that the process does not only show up during initial deployment but can also occur during network operations due to node churn, connectivity loss, mobility, battery replacement, and unexpected disassociation from the network [6]. In addition, within this process, nodes far from the coordinator may lose a considerable amount of energy before joining the TSCH network, which might impact their lifetime [7]. ...
... Authors of [7] proposed a new beacon advertising algorithm based on a custom Trickle timer that allows nodes to increase or decrease the EB period periodically. However, this customized Trickle timer is not adaptive. ...
... For instance, according to [7] and the implementation proposed by [30], a TSCH node turns its radio only for T rx = 5.452ms with a 10ms RX timeslot to receive a packet. Accordingly, we just need to ensure that we can get at least two EBR strobes within this T rx time. ...
The IEEE 802.15.4 TSCH standard is designed to improve the reliability, timeliness, and energy efficiency of short-range wireless communications in industrial applications. TSCH relies upon a network formation process to efficiently create and maintain a synchronized reliable mesh network. The standard adopts a purely passive scan mechanism enabling joining nodes to listen to periodic Enhanced Beacons (EBs) in order to locate a TSCH network and associate to it. Nevertheless, the standard defines neither the advertisement strategy nor the rate at which the EBs should be sent. Consequently, long (re)association times might be observed, which postpones the proper functioning of the network and might have devastating consequences on the industrial application. In this paper, we propose a Fast and Active Network formation scheme (FAN) that leans on active scan procedures and Trickled beacon advertising strategies to accelerate the (re)association process. To do so, FAN equips joiners with a collision avoidance mechanism and allows them to initiate EB requests, on free channels, to trigger EBs. FAN is implemented in Contiki and evaluated through extensive realistic simulations and public testbed experiments. Obtained results assert the robustness of FAN compared to state-of-the-art solutions in terms of association times and overhead.
... This generates a rotation of the physical channels in each slot frame that helps reduce the points of interference and path fading, increasing reliability. The problem here is that a large number of channels have a longer synchronization time [21]. ...
IWSNs (Industrial Wireless Sensor Networks) have become the next step in the evolution of WSN (Wireless Sensor Networks) due to the nature and demands of modern industry. With this type of network, flexible and scalable architectures can be created that simultaneously support traffic sources with different characteristics. Due to the great diversity of application scenarios, there is a need to implement additional capabilities that can guarantee an adequate level of reliability and that can adapt to the dynamic behavior of the applications in use. The use of SDNs (Software Defined Networks) extends the possibilities of control over the network and enables its deployment at an industrial level. The signaling traffic exchanged between nodes and controller is heavy and must occupy the same channel as the data traffic. This difficulty can be overcome with the segmentation of the traffic into flows, and correct scheduling at the MAC (Medium Access Control) level, known as slices. This article proposes the integration in the SDN controller of a traffic manager, a routing process in charge of assigning different routes according to the different flows, as well as the introduction of the Time Slotted Channel Hopping (TSCH) Scheduler. In addition, the TSCH (Time Slotted Channel Hopping) is incorporated in the SDN-WISE framework (Software Defined Networking solution for Wireless Sensor Networks), and this protocol has been modified to send the TSCH schedule. These elements are jointly responsible for scheduling and segmenting the traffic that will be sent to the nodes through a single packet from the controller and its performance has been evaluated through simulation and a testbed. The results obtained show how flexibility, adaptability, and determinism increase thanks to the joint use of the routing process and the TSCH Scheduler, which makes it possible to create a slicing by flows, which have different quality of service requirements. This in turn helps guarantee their QoS characteristics, increase the PDR (Packet Delivery Ratio) for the flow with the highest priority, maintain the DMR (Deadline Miss Ratio), and increase the network lifetime.
