Laboratory: IRISA – GRANIT Team (Lannion)
Thesis Title: Energy management and protocol design for wake-up radio nodes in heterogeneous IoT networks
Key Words: Wireless sensor networks, wake-up radio, microcontroller, energy management, MAC protocols
Starting date: October 2017
Low power communication has evolved towards multi-kilometer ranges and low bit-rate schemes in recent years, triggering increasing interests for Internet of Things (IoT) networks. Using these technologies, a trade-off must be made between power consumption and latency for message transfer from the gateway to the nodes. However, domains such as industrial applications in which sensors and actuators are part of the control loop require predictable latency, as well as low power consumption. These requirements can be fulfilled using pure-asynchronous communication allowed by emerging Ultra-Low-Power (ULP) wake-up receivers (WUR). On the other hand, state-of-the-art wake-up receivers present low sensitivity compared to traditional wireless node receivers, thus allowing short-range communication (few tens of meters), so they have to be combined with other radios to reach longer ranges. This PhD is part of the ANR Wake-up collaborative project (with CEA LETI, Wi6Labs and the University of Strasbourg), aiming at proposing a low latency and energy efficient network architecture composed of heterogeneous radio nodes (long-range communication and ULP short-range WUR) with dedicated access and network protocols.
In previous works, we proved that the use of wake-up radio radically changes the design of the MAC layer and enhances both latency and energy consumption [aitaoudia16ieeeton][le13ensys]. A preliminary study [aitaoudia16dsd] showed that a MAC protocol that combines wake-up radio and LoRa™ can improve downlink latency at a low energy cost. However, an important barrier to be lifted is the robustness of wake-up radios, which are by nature very sensitive and therefore subject to noise perturbations. The wake-up design should both avoid multiple useless wake-ups of the main micro-controllers and radio transceivers of the wireless node while preserving its adaptation capability that will make it very efficient for a whole class of applications. The energy is a crucial point since the more nodes will be deployed the less batteries should be changed to bring companies return on investment for industrial deployments. This means efficient power management policies have to be designed at both node and network levels to ensure the longest possible lifetime for the nodes.
The ambitious nature of this thesis is mainly twofold. On one hand we aim at proposing a new methodology for wake-up radio design, leading to hardware platforms able to deal with different applications within a class, whereas current wake-up radio solutions are very focused in terms of energy consumption and radio range. On the other hand new access and network protocols will be implemented to take profit of this emerging technology. A particular attention is paid to the low complexity of the protocol stack, since the current planning of heterogeneous networks is most often very difficult to deal with. The bidirectional HW/SW cross-layer optimization is also a significant challenge to really make wake-up radios a breakthrough in IoT networking.
The first phase of this work will be dedicated to the bibliography study on energy management and protocol for low-power WSN; a particular attention on WUR-related recent works will be paid.
Then, in order to achieve an efficient cross layer optimization of the IoT node, the communication protocols and the targeted applications/networks, the second phase of the PhD will be to propose an energy modeling of the IoT node leveraging analytical expressions, network simulations and experimental micro-benchmarks [alam11jes].
Finally, the main contribution of this work will be the design of an energy manager (EM) to optimize the energy efficiency of the node. The EM aims at dynamically adapting the power consumption of the node to maximize its performance (latency, sensivity, lifetime… ). A non-trivial challenge is to design efficient adaptation algorithms, suitable for the limited resources provided by wake-up radio nodes in terms of memory, computation power, and energy storage. To operate properly, the PM requires an accurate control of the spent energy according to the possible node’s configurations. To this aim, the models defined in the first phase will be used and embedded in the node to track at run time the consumed energy. The EM will consequently tune wake-up node parameters (wake-up interval, turn on/off wake-up sensor…) according to performance specifications.
The best EM strategy will be implemented on a real wireless sensor platform such as the PowWow platform developed by IRISA [granit13powwow]. A network composed of heterogeneous nodes will be also deployed to confirm this superiority in terms of energy management and quality of service .
The PhD Candidate should have skills in microcontroller programming and wireless communications,. He should be autonomous for the experimental part and have capacities for team work and easy integration.
[akyildiz02jcn] I. Akyildiz, W. Su, Y. Sankarasubramaniam, and E. Cayirci. Wireless sensor networks: a survey. Journal on Computer Networks, 38(4):393–422, 2002.
[alam11jes] M.-M. Alam, O. Berder, D. Ménard et O. Sentieys, A Hybrid Model for Accurate Energy Analysis for WSN, EURASIP Journal on Embedded Systems, 2011.
[le13pimrc] T.N. Le, A. Pégatoquet, O. Sentieys, O. Berder, C. Belleudy. Duty-Cycle Power Manager for Thermal-Powered Wireless Sensor Networks, in 24th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), Londres, United Kingdom, September 2013, pp. 1645-1649.
[le13ensys] T. N. Le, M. Magno, A. Pegatoquet, O. Berder, O. Sentieys, and E. Popovici, “Ultra Low Power Asynchronous MAC Protocol Using Wake-up Radio for Energy Neutral WSN,” in Proceedings of the 1st ACM International Workshop on Energy Neutral Sensing Systems (ENSSys), November 2013.
[aitaoudia16js] F. Aït Aoudia, M Gautier, O Berder, OPWUM: Opportunistic MAC Protocol Leveraging Wake-Up Receivers in WSNs, Journal of sensors, 2016
[aitaoudia16ieeeton] F. Ait Aoudia, M. Gautier, M. Magno, O. Berder, L. Benini , A Generic Framework for Modeling MAC Protocols in Wireless Sensor Networks, IEEE/ACM Transactions on Networking, December 2016, p. 1 – 12
[aitaoudia16dsd] F. Ait Aoudia, M. Magno, M. Gautier, O. Berder, and L. Benini, A Low Latency and Energy Efficient Communication Architecture for Heterogeneous Long-Short Range Communication, 2016 Euromicro Conference on Digital System Design (DSD), August 2016.
(c) GdR 720 ISIS - CNRS - 2011-2015.