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Technical Papers
This page provides a sample of representative technical papers documenting the foundations, testing, and uses of Wi-SUN related standards and technology.
2022
A Straightforward Method to Promote Effective Interoperability in Wi-SUN FAN Smart Grid Networks (2022)
Claudio Ferreira Dias;Lucas Diogo De Mendonça;Karoline Ferreira Tornisiello;Andre Saito Guerreiro;Eduardo Rodrigues De Lima;Gustavo Fraidenraich
With the growing power grid needs in recent years, several different Smart Meters (SMs) have evolved to address diverse challenges. However, interoperability for SMs suppliers is challenging due to the diversity of protocols, data models, and interfaces. In this way, the Wireless Smart Ubiquitous Network (Wi-SUN) is the straightforward solution to address such issue.In this work, we present a simple, low-cost, open-source platform to assess the interoperability with Wi-SUN Field Area Network (FAN) devices. This platform allows the testing of devices under different conditions to check their conformance with the Wi-SUN standard.
Development of Evaluation Systems for Large-Scale Wi-SUN FAN-Based IoT Applications (2022)
Yoshio Kashiwagi;Hiroshi Harada;Hiroko Masaki;Kazuki Osumi
In this study, we developed a USB-type radio board equipped with a wireless smart ubiquitous network (Wi-SUN) field area network (FAN) wireless module capable of performing multi-hops for hundreds of units and an integrated evaluation board to evaluate the transmission performance of Wi-SUN FAN with hundreds of wireless devices in the laboratory. The USB-type radio board achieves low power consumption by controlling the operation of the Wi-SUN FAN wireless module mounted on the board from the outside. Therefore, this study measured the current consumption characteristics. Furthermore, fundamental evaluations of the transmission performance, such as the network configuration time and packet transmission success rate, were performed by configuring a large-scale wireless evaluation system with tree and star topologies using 100 USB-type radio boards and the integrated evaluation boards. A transmission success rate of 95% or higher was achieved continuously for 12 h when all terminals sent a UDP data with a packet length of 200 bytes to the border router of Wi-SUN FAN with a data rate of 100 kbps at the intervals of 150 s.
2021
Wi-SUN Device Authentication using Physical Layer Fingerprint (2021)
Mi-Kyung Oh;Sangjae Lee;Yousung Kang
This paper aims to identify Wi-SUN devices using physical layer fingerprint. We first extract physical layer features based on the received Wi-SUN signals, especially focusing on device-specific clock skew and frequency deviation in FSK modulation. Then, these physical layer fingerprints are used to train a machine learning-based classifier and the resulting classifier finally identifies the authorized Wi-SUN devices. Preliminary experiments on Wi-SUN certified chips show that the authenticator with the proposed physical layer fingerprints can distinguish Wi-SUN devices with 100 % accuracy. Since no additional computational complexity for authentication is involved on the device side, our approach can be applied to any Wi-SUN based IoT devices with security requirements.
A Novel Routing Method with Load-Balancing in Wi-SUN FAN Network (2021)
Rei Hirakawa;Ryota Okumura;Keiichi Mizutani;Hiroshi Harada
This paper proposes a novel routing method considering load balancing to improve transmission characteristics of a large-scale Wi-SUN field area network (Wi-SUN FAN) based on IEEE 802.15.4. Wi-SUN FAN is a wireless communication standard that enables the interconnection of many Internet-of-Things (IoT) devices outdoors. Wi-SUN FAN prevents packet collisions by frequency hopping in the media access control (MAC) layer. Besides, Wi-SUN FAN constructs multi-hop networks autonomously using Internet protocol version 6 routing protocol for low-power and lossy networks (RPL) at the network layer. In RPL, each node determines its parent node based on the quality of communication. Therefore, many nodes are likely to choose the same parent node with good radio reachability, resulting in many packets being sent to the parent node. The heavy load for the specific node makes frequency hopping not work effectively, and transmission characteristics deteriorate. The proposed routing method with a load-balancing algorithm eliminates the load concentration and improves the average transmission success rate by approximately 9.4% on the specific nodes.
Enhancing Wi-SUN AMI Network Resilience by using Emergency Gateway with Optimal Placement (2021)
Amnart Boonkajay;Peng Hui Tan;Lee Kee Goh;Syed Naveen Altaf Ahmed;Sumei Sun
Radio interference or jamming can cause isolated area in advanced metering infrastructure (AMI) based on Wire-less smart utility network (Wi-SUN), in which conventional recovery techniques cannot cope with. In this paper, we deploy narrowband internet-of-things (NB-IoT) interface to some smart meters to act as emergency gateway, called ResiLite. An optimal ResiLite placement algorithm for enhancing network resilience is proposed. We define an implicit resilience metric based on path diversity and cluster closeness. The defined metric is used to form an integer linear programming (ILP) problem, then we solve the ILP to obtain optimal ResiLite placement. Simulation results show that the optimal ResiLite placement improves Wi-SUN AMI network resilience (defined as the number of surviving nodes with packet delivery ratio (PDR) above 99% under disturbance) by up to 167% compared to an AMI without ResiLite, and up to 29% compared to uniformly random ResiLite placement, respectively.
2020
A Home Area Heterogeneous Wireless Management Scheme by Wi-SUN FAN and Wi-Fi Systems (2020)
Kiyoshi Mizutani;Ryota Okumura;Keiichi Mizutani;Hiroshi Harada
In this paper, we propose a heterogeneous wireless management scheme for a home area network (HAN) system. The HAN system integrates multiple wireless systems (e.g., the Wi-Fi operating in the 2.4 GHz-band and the Wi-SUN field area network (Wi-SUN FAN) operating in the sub-GHz-band) for the in-home health care management system. The system assumes a medical care and proactive health management, and a variety of data such as the vital data, the environment data, and the user activity data are collected to a coordinator by using IoT gateways (IoT-GWs). For the transmission scheme between the loT-GWs, we compare two schemes; the conventional FAN scheme and the proposed fast-path scheme. In the FAN scheme, all of the measured data are collected by using the Wi-SUN FAN multi-hop transmission. On the other hand, the proposed fast-path scheme uses both the Wi-Fi and the Wi-SUN FAN, and a part of the data is offloaded to the Wi-Fi from the Wi-SUN FAN. These two schemes are evaluated by computer simulations. In the case that only the vital and environmental data are collected to the coordinator, these data can be collected with the end-to-end (E2E) transmission success rate of 98 % in the proposed fast-path scheme compared with 92 % in the conventional FAN scheme.
An Interference-Aware Optimal Data Collection Scheduling for Wi-SUN Advanced Metering Infrastructure Network (2020)
Amnart Boonkajay;Peng Hui Tan;Lee Kee Goh;Syed Naveen Altaf Ahmed;Sumei Sun
Advanced metering infrastructure (AMI) based on Wireless Smart Utility Network (Wi-SUN) employs carrier sense multiple access (CSMA), hence suffers from poor network performance when the number of nodes increases but without proper design of data collection scheduling. In this paper, we introduce an interference-aware TDMA-like optimal data collection scheduling, in which a link-timeslot assignment problem is formed by considering interference constraint to achieve better spatial timeslot reuse. A constraint for achieving consecutive flow for multi-hop transmission is also introduced to avoid modifications on the original CSMA protocol, and hence the proposed scheduling is standard compliant. Our results show that the proposed scheduling reduces the total data collection time of Wi-SUN AMI network with 100(200) smart meters by 59%(48%), 33%(32%), and 19%(13%), respectively, when compared with conventional Wi-SUN AMI, conventional TDMA scheduling and heuristic scheduling based on 2-rank distance interference model.
Video Transmission Trial by Wireless Multi-hop Network based on Wi-SUN FAN (2020)
Reo Gakumi;Hiroko Masaki;Keiichi Mizutani;Hiroshi Harada
The wireless smart ubiquitous network field area network (Wi-SUN FAN), a wireless communication standard for Internet of Things (IoT) applications, such as smart metering and monitoring, has been attracting attention. Conventionally, the information transmitted by the Wi-SUN FAN is numerical values and/or character strings, such as metering information. It has been thought that the Wi-SUN FAN cannot transmit video images because the data rate is at most in hundreds of kbps. However, owing to improvements in video compression and transmission technologies in recent years, video images can be transmitted at a transmission rate of hundreds of kbps. In this study, the feasibility of video transmission over the Wi-SUN FAN is evaluated using low-rate video compression and transmission technology. First, several network topologies for video transmission by the current Wi-SUN FAN with multi-hop are evaluated by computer simulations. Consequently, adequate numbers of nodes and multi-hops in the Wi-SUN FAN are recommended. Subsequently, using a recommended value, an experimental system is configured and the video transmission performance over the Wi-SUN FAN is evaluated experimentally.
A High-speed Wi-SUN FAN Network by Highly-Dense Frequency Hopping (2020)
Hidetomo Ochiai;Kiyoshi Mizutani;Ryota Okumura;Keiichi Mizutani;Hiroshi Harada
The wireless smart ubiquitous network (Wi-SUN) field area network (FAN) attracts attention as a wireless communication standard for large-scale Internet of Things (IoT) systems. Currently, frequency shift keying (FSK) defined in IEEE 802.15.4 is adopted in the physical layer of the Wi-SUN FAN. To improve the network performance toward next-generation IoT systems, a data rate enhancement scheme for FSK has been proposed. However, there is no evaluation of data rate improvement effect by adopting the data rate enhanced FSK on the transmission characteristics of the Wi-SUN FAN. Besides, introducing the data rate enhanced FSK causes the bandwidth to increase. For multiple systems to coexist in limited frequency bands, it is necessary to achieve high spectral efficiency even when the Wi-SUN FAN adopts the data rate enhanced FSK. In this paper, we evaluate the transmission characteristics of the Wi-SUN FAN adopting the high-speed FSK of 600 kbps by computer simulations. The simulation results show that the system throughput improves by 2.5 times, but the bandwidth also increases by 2.5 times compared to the existing system. Furthermore, we propose highly-dense frequency hopping based on a novel channel arrangement scheme to improve spectral efficiency and compatibility with the existing system design while the data rate enhanced FSK is adopted. The evaluation results show that the system throughput in the proposed scheme is 2.4 times of the existing system while using less than half of the bandwidth compared to the conventional channel arrangement scheme.
A Scheduling Scheme For Channel Hopping In Wi-Sun Fan Systems Toward Data Throughput Enhancement (2020)
Robby Wayong;Ryota Okumura;Keiichi Mizutani;Hiroshi Harada
Wireless smart utility network field area network (Wi-SUN FAN), which configures very large-scale multi-hop networks, has been standardized to promote interoperable open standards for machine-to-machine (M2M) communication. In the media access control (MAC) layer, Wi-SUN FAN adopts a carrier sense multiple access with collision avoidance (CSMA/CA) and a channel hopping (CH) to avoid interferences between devices. A channel schedule controls the operational channel of CH and it is dominant for both unicast and broadcast transmission performances. In this paper, the impact of channel schedule on the network performance is studied to enhance the unicast transmission throughput. The transmission throughput of a Wi-SUN FAN system in four multiple tandem topologies are evaluated by computer simulations in various channel schedule schemes. The simulation results show that by adopting CH and setting the broadcast interval (BI) coefficient to the optimal value that depends on the network topology, higher unicast throughput can be achieved and the transmission interval of broadcast control frames can be preserved at 131 s. In the case of a multiple tandem topology that consists of 33 devices, by adopting CH and setting the BI coefficient to be 30, the unicast throughput increases by up to 12.2% compared to the case of default parameter configuration recommended in Wi-SUN FAN standard.
Prior to 2020
A dynamic routing protocol supporting mobile nodes in Wi-SUN FAN systems (2017)
Thidarut Junjalearnvong; Takuya Habara; Ryota Okumura; Keiichi Mizutani; Hiroshi Harada
Wireless Smart Utility Network (Wi-SUN) has been standardized to provide Machine-to-Machine (M2M) communication in Low power and Lossy Networks (LLNs). Wi-SUN Field Area Network (FAN) is the specification that maintains a wireless multi-hop communication on the advanced smart city infrastructure. Wi-SUN FAN has adopted the Internet Protocol version 6 (IPv6) Routing Protocol for LLNs (RPL) which has been successfully optimized in fixed terminals. To establish the embedded smart city, mobile nodes are required to implement the RPL as well. Nevertheless, the RPL fails to choose the appropriate routing node when the terminal moves, resulting in high packet loss. To improve the transmission performance, the system simulator of Wi-SUN FAN with the Expected Transmission Count (ETX) based algorithm is firstly developed to evaluate the end-to-end transmission success rate via multi-hop transmission and the simulation result clarifies that the critical factor causing low transmission performance is the unsmooth handover of the receiver node at first hop. Then, a dynamic routing algorithm based on ETX transition is proposed and the simulation result finally assures the smooth handover, resulting in the improved transmission performance.