Adrien Van den Bossche

An advanced study of energy consumption in an IEEE 802.15.4 based network: Everything but the truth on 802.15.4 node lifetime

In this paper, the authors present a global study on energy considerations in the context of a wireless network based on the well-known IEEE 802.15.4 technology. Various tests have been carried out on a node prototype powered by Lithium batteries in order to determine the lifetime of this network element, in several cases including 802.15.4 coordinator or end device configurations but also non-802.15.4 protocols. The results show that the lifetime is clearly dependent on the node receiving state time, which has a big impact on not only the network performance like throughput and latency but also the energy budget of the battery. The paper also illustrates the non-linear characteristic of the battery capacity. Finally, it identifies drawbacks which may be avoided in the future design of MAC (Medium Access Control) protocols in order to maximize node lifetime.

Cross-layering in an Industrial Wireless Sensor Network: Case Study of OCARI

Wireless sensor networks are adapted to monitoring applications. Specific solutions have to be developed for industrial environments in order to deal with the harsh radio conditions and the QoS (quality of service) requirements of industrial applications. In this paper, we present the main protocols used in the OCARI project, and we describe their use of cross-layering techniques. We show how it enables us to improve the performance of the network. For each protocol, we give a performance evaluation of its main characteristic.

PROTOTYPING AND PERFORMANCE ANALYSIS OF A QoS MAC LAYER FOR INDUSTRIAL WIRELESS NETWORK

Abstract Todays industrial sensor networks require strong reliability and guarantees on messages delivery. These needs are even more important in real time applications like control/command, such as robotic wireless communications where strong temporal constraints are critical. For these reasons, classical random-based Medium Access Control (MAC) protocols present a non-null frame collision probability. In this paper we present an original full deterministic MAC-layer for industrial wireless network and its performance evaluation thanks to the development of a material prototype. Copyright

SISP: A lightweight synchronization protocol for Wireless Sensor Networks

This paper presents a new synchronization protocol suitable for light nodes in a Wireless Sensor Network. This protocol, called SISP, is detailed with its algorithm and its sequence diagram. The simulation results obtained with a dedicated simulator are completed by the results of prototyping. The results show the effectiveness of SISP. Several prospects are discussed in conclusion.

Comparison of Indoor Localization Systems Based on Wireless Communications

Localization using a Wireless Sensor Network (WSN) has become a field of interest for researchers in the past years. This information is expected to aid in routing, systems maintenance and health monitoring. For example, many projects aiming to monitor the elderly at home include a personal area network (PAN) which can provide current location of the patient to the medical staff. This article presents an overview of the current trends in this domain. We introduce the mathematical tools used to determine position then we introduce a selection of range-free and range-based proposals. Finally, we provide a comparison of these techniques and suggest possible areas of improvement.

Performance evaluation of IEEE 802.15.6 CSMA/CA-based CANet WBAN

In the recent few years, Wireless Body Area networks (WBANs) showed what can be done remotely to greatly improve healthcare systems and facilitate the life to elderly. One of the recent ehealth projects is CANet which aims at embedding a WBAN into a cane to monitor elderly/patients. Our main goal in this paper is to evaluate the performances of the emerging standard IEEE 802.15.6 when applied on different sensors from CANet eHealth project. At this end, we defined a small scenario extracted from CANet, and we assigned IEEE 802.15.6 priorities to the selected cane sensors according to their inherent characteristics. We considered further the mandatory RAP period of IEEE 802.15.6 superframe under the beacon period with superframes mode since it supports both normal and urgent traffic. Our results showed that the contention access behavior of this considered model of simulation depends on several constraints (including the nature of the studied application and the traffic types and frequency). This would be necessarily taken into account to get the most advantage of all features offered by WBANs standard IEEE 802.15.6.

Indoor self-localization in a WSN, based on Time Of Flight: Propositions and demonstrator

IEEE 802.15.4 is a widely adopted foundation for the lower layers of wireless sensor networks. This standard has recently started to take localization into account. This has led to the addition of two new PHY layers, Ultra-Wide Band (UWB) and Chirp Spread Spectrum (CSS), but also the specification of a Time Of Flight-based ranging protocol named Symmetric Double-Sided Two-Way Ranging (SDS-TWR). This paper describes the results obtained from a CSS-based prototype using a variant of SDS-TWR. Our solution differs from others exploiting the same tools by not involving a localization server. The location estimation algorithm is executed by the mobile node, right after the ranging phase. The obtained localization error is generally under 200cm in 90% of the situations and the mean error is around 1m.

OpenWiNo: An open hardware and software framework for fast-prototyping in the IoT

The Internet of Things promises an always-connected future where the objects surrounding us will communicate in order to make our lives easier, more secure, etc. This evolution is a research opportunity as new solutions must be found to problems ranging from network interconnection to data mining. In the networking community, innovative solutions are being developed for the Device Layer of the Internet of Things, which includes the IoT wireless protocols. In order to study their performance, researchers turn more often to real world platforms, commonly designated by the term “testbeds”, on which they may implement and test the protocols and algorithms. This is even more important in the Industrial IoT field, where environments are perturbed by industrial systems like automated production systems. In this paper, after a brief presentation of the context of testbeds, we introduce WiNo and OpenWiNo, an open hardware and software framework for fast-prototyping in the field of the Internet of Things. Compared to existing platforms, the solution WiNo+OpenWiNo offers a wide array of Physical layers and easy integration of various sensors as it is developed as part of the Arduino ecosystem. It also allows research teams to easily and quickly deploy their own testbed into real environments.

An experimental performance study of an original ranging protocol based on an IEEE 802.15.4a UWB testbed

In this article, we study the behaviour of an Ultra-Wide Band (UWB) physical layer when executing our protocol Parallel Symmetric Double-Sided Two-Way Ranging. We compare it to the reference protocol introduced in IEEE 802.15.4a Symmetric Double-Sided Two-Way Ranging, in terms of precision of the obtained estimates and to other existing protocols such as SDS-TWR-MA and D-TWR in terms of overhead. These samples were obtained using a testbed made of IEEE 802.15.4a UWB nodes. From these first experiments, we derive a simple correction mechanism which reduces the localisation error compared to the case where no dynamic correction takes place. The location error reduction varies between 41 and 60% while the algorithm manages to estimate the position 99.9% of the time with the addition of the correction.

Towards an optimised traffic-aware routing in wireless mesh networks

In this paper we study through simulations the impact of PHY/MAC protocols on higher layers. In a comparative way, we investigate the effectiveness of some protocols when they coexist on a wireless mesh network environment. Results show that PHY/MAC parameters have an important impact on routing performances. Based on these results, we propose two tra c-aware routing metrics based on link availability. The information about the link availability/occupancy is picked up from lower layers using a cross-layer approach. The rst metric is load-sensitive and aims to balance the tra c load according to the availability of a link to support additional ows. The second metric reproduces better the capacity of a link since it is based on its residual bandwidth. Using several real experiments, we have shown that our proposals can accurately determine better paths in terms of throughput and delay. Our experiments are carried out into an heterogeneous IEEE 802.11n based network running with OLSR routing protocol.