scholarly journals A virtual slotframe technique for reliable multi-hop IEEE 802.15.4e time-slotted channel hopping network

2018 ◽  
Vol 14 (7) ◽  
pp. 155014771879075
Author(s):  
Yuvin Ha ◽  
Sang-Hwa Chung
Keyword(s):  
Access Control ◽  
Conventional Method ◽  
High Reliability ◽  
Data Traffic ◽  
Medium Access ◽  
Dynamic Changes ◽  
Link Failures ◽  
Channel Hopping ◽  
Simulation Results ◽  
Ieee 802.15.4E

Time-slotted channel hopping is one of the medium access control modes defined in IEEE 802.15.4e. Although time-slotted channel hopping provides high reliability, it cannot be achieved automatically. A time-slotted channel hopping should be configured properly according to the dynamic changes in a network. When new devices participate in the network or the data traffic is increased, link allocation may not be possible due to the fixed slotframe length. The simplest way to acquire additional links is to change the length. However, the conventional method to change this length involves significant overhead and the possibility of link failures. In this article, we evaluate the performance of the conventional IEEE 802.15.4e method and analyze the problems that can occur when changing the slotframe length. To resolve these problems, we propose a virtual slotframe technique that forms a logical slotframe by connecting multiple slotframes. A slot scheduler will then perceive the virtual slotframe as merely a long slotframe. The devices can translate the schedules made for the longer slotframe into real links using the virtual slotframe technique. These features allow the time-slotted channel hopping network to allocate additional slots without reconfiguration. The simulation results show that the proposed technique is a maximum of 18 times and an average of 10 times faster than the conventional method.

scholarly journals Collision-Free Advertisement Scheduling for IEEE 802.15.4-TSCH Networks

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1789 ◽  
Author(s):  
Apostolos Karalis ◽  
Dimitrios Zorbas ◽  
Christos Douligeris
Keyword(s):  
Power Consumption ◽  
Ieee 802.15.4 ◽  
Mac Protocol ◽  
High Reliability ◽  
Mobile Nodes ◽  
Medium Access ◽  
Worst Case ◽  
Channel Hopping ◽  
Transmission Schedule ◽  
Scheduling Method

IEEE802.15.4-time slotted channel hopping (TSCH) is a medium access control (MAC) protocol designed to support wireless device networking, offering high reliability and low power consumption, two features that are desirable in the industrial internet of things (IIoT). The formation of an IEEE802.15.4-TSCH network relies on the periodic transmissions of network advertising frames called enhanced beacons (EB). The scheduling of EB transmissions plays a crucial role both in the joining time and in the power consumption of the nodes. The existence of collisions between EB is an important factor that negatively affects the performance. In the worst case, all the neighboring EB transmissions of a node may collide, a phenomenon which we call a full collision. Most of the EB scheduling methods that have been proposed in the literature are fully or partially based on randomness in order to create the EB transmission schedule. In this paper, we initially show that the randomness can lead to a considerable probability of collisions, and, especially, of full collisions. Subsequently, we propose a novel autonomous EB scheduling method that eliminates collisions using a simple technique that does not increase the power consumption. To the best of our knowledge, our proposed method is the first non-centralized EB scheduling method that fully eliminates collisions, and this is guaranteed even if there are mobile nodes. To evaluate our method, we compare our proposal with recent and state-of-the-art non-centralized network-advertisement scheduling methods. Our evaluation does not consider only fixed topology networks, but also networks with mobile nodes, a scenario which has not been examined before. The results of our simulations demonstrate the superiority of our method in terms of joining time and energy consumption.

scholarly journals Enhancing SDN WISE with Slicing Over TSCH

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1075
Author(s):  
Federico Orozco-Santos ◽  
Víctor Sempere-Payá ◽  
Teresa Albero-Albero ◽  
Javier Silvestre-Blanes
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Control Level ◽  
Wireless Sensor ◽  
Delivery Ratio ◽  
Data Traffic ◽  
Medium Access ◽  
Industrial Wireless Sensor Networks ◽  
Channel Hopping ◽  
Industrial Level

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.

scholarly journals A Reservation Protocol Analysis for Multi-Channel Wireless Networks

2017 ◽  
Vol 2 (4) ◽  
pp. 340
Author(s):  
Peristera A. Baziana ◽  
Ioannis E. Pountourakis
Keyword(s):  
Access Control ◽  
Network Performance ◽  
Mac Protocol ◽  
Local Area ◽  
Substantial Contribution ◽  
Data Traffic ◽  
Medium Access ◽  
Reservation Protocol ◽  
Single Radio ◽  
Multi Access

A synchronous multi-channel multi-access Medium Access Control (MAC) protocol for Wireless Local Area Networks (WLANs) is studied in this paper. The proposed protocol introduces an access control reservation scheme and requires a single radio per station. The receiver collisionsphenomenon characterizes the performance of the proposedmulti-channel system. A priority scheme is considered in order to primary serve the time-sensitive traffic such as voice, as compared to the delay tolerant data traffic. The innovation of this paper is the extensive and accurate study of the receiver collisions effect on the network performance in multi-traffic environment. An analytic discrete time Markovian model is developed for finite number of stations and channels. The performance measures of throughput, delay, and average rejection probability at destination are analytically estimated. Numerical results are presented for comparison for various numbers of channels and stations. The proposed MAC protocol provides a substantial contribution to the understanding of wireless multi-channel multi-traffic environments.

Timeslot Allocation Scheme for Cognitive Satellite Networks

2011 ◽  
Vol 230-232 ◽  
pp. 40-43 ◽  
Author(s):  
Li Na Wang
Keyword(s):  
Access Control ◽  
Medium Access Control Protocol ◽  
Satellite Networks ◽  
Prediction Algorithm ◽  
Random Allocation ◽  
Allocation Scheme ◽  
Medium Access ◽  
Primary Users ◽  
Backoff Algorithm ◽  
Simulation Results

In this paper, we investigated timeslot allocation scheme in medium access control protocol for cognitive satellite networks. The timeslots for satellite primary users were allocated according to the reserve channel with priority fit algorithm and the timeslots for cognitive users were allocated according to the prediction algorithm. Compared to random allocation scheme, the correction ratio of timeslot allocation using the prediction algorithm was improved. The proposed timeslot allocation scheme adopted the combined backoff algorithm to avoid collisions. And then the improved throughput and the reduced delay could be obtained. Simulation results verify the effectiveness of the proposed timeslot allocation scheme.

scholarly journals Transmission Scheduling of Periodic Real-Time Traffic in IEEE 802.15.4e TSCH-Based Industrial Mesh Networks

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Ke Shi ◽  
Lin Zhang ◽  
Zhiying Qi ◽  
Kang Tong ◽  
Hongsheng Chen
Keyword(s):  
Real Time ◽  
Mesh Networks ◽  
High Reliability ◽  
Industrial Applications ◽  
Maximum Matching ◽  
Mesh Topology ◽  
Dynamic Priority ◽  
Real Time Traffic ◽  
Channel Hopping ◽  
Ieee 802.15.4E

Time-slotted channel hopping (TSCH) is a part of an emerging IEEE 802.15.4e standard to enable deterministic low-power mesh networking, which offers high reliability and low latency for wireless industrial applications. Nonetheless, the standard only provides a framework, but it does not mandate a specific scheduling mechanism for time and frequency slot allocation. This paper focuses on a centralized scheme to schedule multiple concurrent periodic real-time flows in TSCH networks with mesh topology. In our scheme, each flow is assigned a dynamic priority based on its deadline and the hops remaining to reach the destination. A maximum matching algorithm is utilized to find conflict-free links, which provides more chances to transfer high-priority flows at each time slot. Frequency allocation is implemented by graph coloring to make finally selected links interference free. Simulation results show that our algorithm clearly outperforms the existing algorithms on the deadline satisfaction ratio with a similar radio duty cycle.

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