Low-power Wireless Networks Research Articles

SA-RPL: a scheduling-aware forwarding mechanism in RPL/TSCH-operated networks

Wireless sensor networks have shown to be a promising technology for industrial automation in which continuous monitoring is a critical requirement. Deploying an energy-aware sensor network permits increasing the network lifetime and prolonging the monitoring operation. IEEE 802.15.4e and RPL have been used as de-facto protocols at the access and network layer in low power and low-rate wireless networks. Specifically, the time slotted channel hopping (TSCH) of 802.15.4e has been designed to provide a reliable access method in low power and lossy networks. More importantly, the combination of TSCH and RPL facilitates providing load-balancing together with energy-saving in such networks. This paper proposes schedule aware RPL (SA-RPL) which aims at prolonging the network lifetime while improving load balancing. It periodically collects scheduling matrix information form TSCH to compute a new measure for selecting the next hop at the network layer. More precisely, the parent with minimum number of occupied cells is more likely to be chosen as the preferred parent. To evaluate the performance of SA-RPL, we modified a distributed management scheme already developed in NS2 simulator. Simulation results show that SA-RPL, compared with other methods, prolongs the network lifetime up to two times and achieves a more uniform energy consumption distribution without decreasing other performance metrics.

SA-RPL: a scheduling-aware forwarding mechanism in RPL/TSCH-operated networks

Wireless sensor networks have shown to be a promising technology for industrial automation in which continuous monitoring is a critical requirement. Deploying an energy-aware sensor network permits increasing the network lifetime and prolonging the monitoring operation. IEEE 802.15.4e and RPL have been used as de-facto protocols at the access and network layer in low power and low-rate wireless networks. Specifically, the time slotted channel hopping (TSCH) of 802.15.4e has been designed to provide a reliable access method in low power and lossy networks. More importantly, the combination of TSCH and RPL facilitates providing load-balancing together with energy-saving in such networks. This paper proposes schedule aware RPL (SA-RPL) which aims at prolonging the network lifetime while improving load balancing. It periodically collects scheduling matrix information form TSCH to compute a new measure for selecting the next hop at the network layer. More precisely, the parent with minimum number of occupied cells is more likely to be chosen as the preferred parent. To evaluate the performance of SA-RPL, we modified a distributed management scheme already developed in NS2 simulator. Simulation results show that SA-RPL, compared with other methods, prolongs the network lifetime up to two times and achieves a more uniform energy consumption distribution without decreasing other performance metrics.

Guest Editorial: Special Issue on Large-Scale Wireless-Powered Networks With Backscatter Communications

The Proliferation of connected and embedded devices has played a critical role in the development of next generation Internet of Things (IoT), and consequently, the diffusion of low power networks. The sustainability of such networks entails energy aware devices that are capable of self-sustainable operations by harvesting and recycling energy from various sources. Accordingly, integration of wireless-powered networks (WPN) with ambient backscatter communications (AmBC), in which a backscatter transmitter conveys data to a destination by backscattering ambient signals, has recently emerged as a promising key technology for low power wireless networks. However, these technologies are not optimized and/or designed for large-scale networks and a massive number of IoT devices.

Know when to listen: SDN-based protocols for directed IoT networks

Low-power wireless networks are an integral part of the Internet of Things, composed of resource-constrained devices harvesting ambient information. The appearance of unidirectional links is characteristic of low power wireless networking due to physical effects, device heterogeneity and manufacturing imperfections. Despite the prevalence of unidirectional links, most routing and radio duty cycling protocols designed for these networks do not account for such links. We provide unidirectional-link-capable protocols and study the impact of using such links on network performance indicators, such as the data delivery ratio, delay and energy consumption. Our protocols are flexible and flooding-free, leveraging centralized knowledge provided by the Software-Defined Networking paradigm. Our experiments reveal that, while unidirectional links must be detected, using them for routing enhances network performance only if the unidirectional links are long.

Fast Feedback Control over Multi-hop Wireless Networks with Mode Changes and Stability Guarantees

Closing feedback loops fast and over long distances is key to emerging cyber-physical applications; for example, robot motion control and swarm coordination require update intervals of tens of milliseconds. Low-power wireless communication technology is preferred for its low cost, small form factor, and flexibility, especially if the devices support multi-hop communication. Thus far, however, feedback control over multi-hop low-power wireless networks has only been demonstrated for update intervals on the order of seconds. To fill this gap, this article presents a wireless embedded system that supports dynamic mode changes and tames imperfections impairing control performance (e.g., jitter and message loss), and a control design that exploits the essential properties of this system to provably guarantee closed-loop stability for physical processes with linear time-invariant dynamics in the presence of mode changes. Using experiments on a cyber-physical testbed with 20 wireless devices and multiple cart-pole systems, we are the first to demonstrate and evaluate feedback control and coordination with mode changes over multi-hop networks for update intervals of 20 to 50 milliseconds.

An Internet of Things (IoT) Application on Volcano Monitoring.

In the last few years, there has been a huge interest in the Internet of Things (hereinafter IoT) field. Among the large number of IoT technologies, the low-power wide-area network (hereinafter LPWAN) has emerged providing low power, low data-rate communication over long distances, enabling battery-operated devices to operate for long time periods. This paper introduces an application of long-range (hereinafter LoRa) technology, one of the most popular LPWANs, to volcanic surveillance. The first low-power and low-cost wireless network based on LoRa to monitor the soil temperature in thermal anomaly zones in volcanic areas has been developed. A total of eight thermometers (end devices) have been deployed on a Teide volcano in Tenerife (Canary Islands). In addition, a repeater device was developed to extend the network range when the gateway did not have a line of sight connection with the thermometers. Combining LoRa communication capabilities with microchip microcontrollers (end devices and repeater) and a Raspberry Pi board (gateway), three main milestones have been achieved: (i) extreme low-power consumption, (ii) real-time and proper temperature acquisition, and (iii) a reliable network operation. The first results are shown. These results provide enough quality for a proper volcanic surveillance.

Application research on Interner access of smart home network based on 6LoWPAN

With the rapid development of Internet of things technology and the increasing diversity and number of devices connected to home Network, the technology of 6LoWPAN (IPv6 over low-power Wireless Personal Area Network) has been widely used in smart home Network. According to the actual needs of users, it will be of more practical significance to connect the smart home network to the Internet (IPv4) so that users can obtain the information in the home network instantly and realize remote control through the mobile application platform.Based on 6 lowpan overall design scheme of smart home network access to the Internet, including the system gateway hardware and software design, and combining the transition technology analysis of the 6 lowpan network access of the Internet technology difficulty, according to the current technical background, we have analyzed based on 6 lowpan technology of smart home network to access the Internet in the next generation Internet development foreground and research significance.

Mobile Edge Aided Data Dissemination for Wireless Healthcare Systems

Recent advances in microelectronic technologies have enabled the design and proliferation of low-power wireless networks for autonomously monitoring and control of wireless healthcare systems. In order to control and update the network nodes (e.g., bug fixing, command distribution, software update) in the healthcare system, reliable and efficient data dissemination is one of the key building blocks. However, traditional data dissemination relies mainly on the Internet of Things (IoT) nodes and thus much energy is wasted. With the development of 5G communication technologies, especially the mobile edge computing (MEC), it is believed that the edge server will become promising and more pervasively deployed. Despite computational offloading, the edge servers are also capable of communicational offloading. Therefore, to achieve data dissemination in an efficient way, we propose an edge-aided data dissemination system, in which the mobile edge servers are used to disseminate different segments of data objects. After that, IoT nodes exchange segments with each other to collect the entire data objects. In our work, we design the installation mechanism and data propagation protocol to not only ensure integrality of the data objects transmitted but also avoid the transmission conflicts. Furthermore, we design an adaptive protocol to achieve efficient data dissemination for heterogeneous IoT networks. We conduct extensive experiments and large-scale simulations. The results demonstrate that with the help of mobile edge servers, the energy efficiency is significantly improved compared to traditional dissemination approaches.

An Improved spectral graph partition intelligent clustering algorithm for low-power wireless networks

Aiming at the problem of energy imbalance and low-energy efficiency in wireless sensor network, a novel energy-balanced clustering routing algorithm based on spectral graph partition is proposed in this paper, which firstly calculates the optimum single-hop distance, balances the energy consumption of cluster heads, and avoids that the number of cluster heads is not fixed and cluster heads are clustered by using the traditional probability function. In addition, the transmission cost function is designed to construct the optimum transmission path to reduce energy consumption. The experimental results show that the network performance of our proposed algorithm is improved, which achieves on low-energy network for loss reduction and load balancing.

Experimental Interference Robustness Evaluation of IEEE 802.15.4-2015 OQPSK-DSSS and SUN-OFDM Physical Layers for Industrial Communications

In this paper, we experimentally evaluate and compare the robustness against interference of the OQPSK-DSSS (Offset Quadrature Phase Shift Keying-Direct Sequence Spread Spectrum) and the SUN-OFDM (Smart Utility Network-Orthogonal Frequency Division Multiplexing) physical layers, as defined in the IEEE 802.15.4-2015 standard. The objective of this study is to provide a comprehensive analysis of the impact that different levels of interference produce on these modulations, in terms of the resulting PDR (Packet Delivery Ratio) and depending on the length of the packet being transmitted. The results show that the SUN-OFDM physical layer provides significant benefits compared to the ubiquitous OQPSK-DSSS in terms of interference robustness, regardless of the interference type and the packet length. Overall, this demonstrates the suitability of choosing the SUN-OFDM physical layer when deploying low-power wireless networks in industrial scenarios, especially taking into consideration the possibility of trading-off robustness and spectrum efficiency depending on the application requirements.

Multicast improvement for LOADng in Internet of Things networks

The Lightweight On-demand Ad hoc Distance-vector Routing Protocol – Next Generation (LOADng) is an emerging routing solution for low-power wireless networks, which is receiving much attention and is being adopted in Internet of Things (IoT) networks. Although the current literature has introduced improvements to allow the protocol to fulfill the requirements of a higher set of IoT applications, the multicast support stills a deficiency of the protocol. Thus, to overcome this limitation, this study proposes a multicast improvement for LOADng. The proposal, named Multicast LOADng (M-LOADng) introduces a new route discovery process to enable the construction of a multicast routing tree and perform forwarding multicast data messages. The proposed solution also introduces mechanisms to reduce the control message overhead and increase the reliability of the route discovery process. Further, M-LOADng allows multicast data transmission in three different modes. The conducted experiments, through a real testbed, show that the proposed solution can reach a reliable and constant performance in terms of quality-of-service, energy consumption, and memory usage, even when increasing the multicast group size.

RapidNet IP: A synchronized, high throughput, low power wireless networking solution for ESL

Electronic shelf labels (ESL) are electronic equivalent of price tags in retail stores, product id labels in large warehouses, and instruction sheets in manufacturing assembly lines. The volume of labels varies up to 1000-12000 in numbers depending on the application. This paper describes novel wire

Control-Guided Communication: Efficient Resource Arbitration and Allocation in Multi-Hop Wireless Control Systems

In future autonomous systems, wireless multi-hop communication is key to enable collaboration among distributed agents at low cost and high flexibility. When many agents need to transmit information over the same wireless network, communication becomes a shared and contested resource. Event-triggered and self-triggered control account for this by transmitting data only when needed, enabling significant energy savings. However, a solution that brings those benefits to multi-hop networks and can reallocate freed up bandwidth to additional agents or data sources is still missing. To fill this gap, we propose control-guided communication, a novel co-design approach for distributed self-triggered control over wireless multi-hop networks. The control system informs the communication system of its transmission demands ahead of time, and the communication system allocates resources accordingly. Experiments on a cyber-physical testbed show that multiple cart-poles can be synchronized over wireless, while serving other traffic when resources are available, or saving energy. These experiments are the first to demonstrate and evaluate distributed self-triggered control over low-power multi-hop wireless networks at update rates of tens of milliseconds.

Optimization of a Piezoelectric Energy Harvester and Design of a Charge Pump Converter for CMOS-MEMS Monolithic Integration.

The increasing interest in the Internet of Things (IoT) has led to the rapid development of low-power sensors and wireless networks. However, there are still several barriers that make a global deployment of the IoT difficult. One of these issues is the energy dependence, normally limited by the capacitance of the batteries. A promising solution to provide energy autonomy to the IoT nodes is to harvest residual energy from ambient sources, such as motion, vibrations, light, or heat. Mechanical energy can be converted into electrical energy by using piezoelectric transducers. The piezoelectric generators provide an alternating electrical signal that must be rectified and, therefore, needs a power management circuit to adapt the output to the operating voltage of the IoT devices. The bonding and packaging of the different components constitute a large part of the cost of the manufacturing process of microelectromechanical systems (MEMS) and integrated circuits. This could be reduced by using a monolithic integration of the generator together with the circuitry in a single chip. In this work, we report the optimization, fabrication, and characterization of a vibration-driven piezoelectric MEMS energy harvester, and the design and simulation of a charge-pump converter based on a standard complementary metal–oxide–semiconductor (CMOS) technology. Finally, we propose combining MEMS and CMOS technologies to obtain a fully integrated system that includes the piezoelectric generator device and the charge-pump converter circuit without the need of external components. This solution opens new doors to the development of low-cost autonomous smart dust devices.

RSS ranging based indoor localization in ultra low power wireless network

Advances in ultra low power based wireless networks have enabled developments of a variety of applications including indoor localization systems. Considering the commercial 2.4 GHz wireless devices choose lower and lower power consumption strategy, it is challenging to design an ultra low power based real time indoor localization system. In ultra low power channel conditions, the rapid increase of received signal strength (RSS) measurement variabilities for the minimum RSS value ranges, the spatiotemporally different RSS attenuations, and the common non-line of sight (NLOS) problems make the indoor localization system significantly inefficient. Considering the practical dynamics of ultra low power indoor wireless channel environments, we propose the indoor localization algorithm which can accommodate the environmental dynamics automatically in real time.

Reduced Overhead Routing in Short-Range Low-Power and Lossy Wireless Networks.

In this paper we present enhanced routing protocol for low-lower and lossy networks (ERPL), a reduced overhead routing protocol for short-range low-power and lossy wireless networks, based on RPL. ERPL enhances peer-to-peer (P2P) route construction and data packet forwarding in RPL’s storing and non-storing modes of operation (MoPs). In order to minimize source routing overhead, it encodes routing paths in Bloom Filters (BF). The salient features of ERPL include the following: (i) optimized P2P routing and data forwarding; (ii) no additional control messages; and (iii) minimized source routing overhead. We extensively evaluated ERPL against RPL using emulation, simulation, and physical test-bed based experiments. Our results demonstrate that ERPL outperforms standard RPL in P2P communication and its optimized P2P route construction and data forwarding algorithms also positively impact the protocol’s performance in multi-point to point (MP2P) and point to multi-point (P2MP) communications. Our results demonstrate that the BF-based approach towards compressed source routing information is feasible for the kinds of networks considered in this paper. The BF-based approach results in 65% lower source routing control overhead compared to RPL. Our results also provide new insights into the performance of MP2P, P2MP, and P2P communications relative to RPL’s destination-oriented directed a-cyclic graph (DODAG) depth, i.e., a deeper DODAG negatively impacts the performance of MP2P and P2MP communications, however it positively impacts P2P communication, while the reverse holds true for a relatively shallow DODAG.

6LoWPAN Fragment Forwarding

Low-power wireless technologies have been applied to industrial fields not only to monitor facilities but also to control them. There is a legitimate requirement to integrate low-power wireless networks with existing IP-enabled networks such as the Internet. The 6LoWPAN standard makes this happen easily by enabling low-power wireless networks to transport IPv6 packets. A challenge is that an IPv6 packet might not fit in a link-layer frame. The answer is fragmentation: the IPv6 packet is cut into fragments, each fitting in a frame. In a typical implementation, the IPv6 packet is fragmented and reassembled at every hop. Such per-hop reassembly causes low endto- end reliability and high end-to-end latency. This article presents a new implementation technique that results in fragment forwarding without changing any of the standards. Simulation results show how, when going from per-hop reassembly to fragment forwarding, end-to-end reliability goes from 40 percent to 100 percent, memory requirements go from 1280 B to 160 B, and end-to-end latency is halved.

Understanding Path Reconstruction Algorithms in Multihop Wireless Networks

Low-power and multihop wireless networking is envisioned as a promising technology to achieve both energy efficiency and easy deployment for many Internet of Things (IoT) applications. Measuring packet-level path is crucial for managing large-scale multihop wireless networks. Packet-level path information encodes the routing path, a packet that takes through a network. The availability of packet-level path information can greatly facilitate many network management tasks. It is challenging to reconstruct packet-level paths using a small overhead, especially for large-scale networks. While there is a long list of existing path reconstruction algorithms, these algorithms focus on specific network scenarios, e.g., periodic monitoring networks or event detection networks. There lacks a unified model for systematically understanding and comparing the performance of these algorithms in different network scenarios. In this paper, we fill this gap by proposing an abstract model. Using this model, it is possible to derive a decision space for selecting the best algorithm for different networks. Furthermore, this model also guides us to devise better path reconstruction algorithms (cPath <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">τ,</sub> cPath <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s,</sub> and cPath <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sT</sub> ) with respect to path reconstruction ratio. Extensive experiments demonstrate the prediction power of our model as well as the advantages of our proposed algorithms. The results show that our algorithm (cPath <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sT</sub> ) improves a path reconstruction ratio from 94.4%, 34.3%, and 30.8% to 98.9%, 99.9%, and 60.1% on average in three network scenarios, respectively, compared with the best state-of-the-art algorithms.

A Review of An Energy Efficient Communication Scheme for Low Power Wireless Network

A Review of An Energy Efficient Communication Scheme for Low Power Wireless Network

Energy Depletion Attacks in Low Power Wireless Networks

Low Power Wireless (LPW) networks have recently been emerging as key candidates to offer affordable connectivity for the constrained devices in the Internet of Things (IoT). However, they also raise major security concerns due to the inherent security vulnerabilities of built-in communication protocols. By exploiting these flaws, an adversary can attack sensors or actuators in an LPW network and force them to execute energy-hungry tasks such as verifying unauthenticated garbage messages repeatedly. This attack, namely energy depletion attack (EDA), can drain the batteries of the devices rapidly and lead to soaring network-wide energy expenditure. Consequently, the offense can leave the victims disabled, and even shut down the whole network due to the battery exhaustion of all the devices. In this paper, we investigate existing studies and provide a systematic review of EDAs and defenses in LPW networks. Through this work, we conclude that most existing LPW technologies are vulnerable to EDAs. This paper also indicates the security challenges in LPW networks related to EDAs along with the potential research directions. While LPW technologies have already hit the market with the promising deployment schedules, our attempt can inspire the research community to enhance the security of underlying protocols that will shape the connectivity of billions of devices in the future IoT ecosystem.