25 research outputs found
MEES-WuR: Minimum Energy Coding with Early Shutdown for Wake-up Receivers
International audienceOne of the main challenges of wireless sensor networks is to maintain sensor nodes alive as long as possible, and a lot of efforts are dedicated to enable energy efficient communications. Wake-Up Receivers (WuRs) represent a promising solution for reducing the power consumption of nodes by enabling asynchronous communications. However, to achieve an ultra-low power consumption, WuRs circuits are kept as simple as possible, inducing a low sensitivity and thus a short range communication. As channel coding improves sensitivity, we propose to take advantage of the computing capability of the WuRs to apply a specific channel coding. The novelty resides in applying Minimum Energy coding with an Early Shutdown (MEES) of WuRs based on On-Off Keying (OOK) detectors. Both theoretical derivations and Monte-Carlo simulations show that the proposed coding scheme improves the reliability. Moreover, Moreover, MEES has been implemented on a non-coherent WuR prototype, and it is shown through experimentation that WuR reliability can be raised up to 22% compared to uncoded communications. Moreover, both the energy consumption and the latency can be significantly decreased thanks to the shutdown mechanism of MEES
Enhancing Wake-Up Radio Range Through Minimum Energy Coding
International audienceA substantial part of the research on wireless sensor networks is focused on the optimization of the energy consumption through either hardware or protocol communication stacks. Wake-up Receivers (WuRs) represent a new paradigm that offers both ultra low power consumption and low latency through asynchronous communications. However, WuRs have a low sensitivity and thus can misinterpret the received signal inducing a performance degradation of the whole communicating system. To tackle this issue, low power channel coding techniques can be used and we propose in this work to apply Hamming coding and Minimum Energy Coding (ME) to enhance WuR range. A performance study of these two types of coding shows that ME coding outperforms Hamming code in reducing both bit error rate and energy consumption. At a range of 28 m, ME coding saves about 3 times the energy at a bit error rate of compared to uncoded scheme. Furthermore, experimentation on the missed wake-ups when applying ME coding was done, showing a gain of 22% in reliability compared to uncoded scheme
Implémentation du codage à minimum d'énergie pour les wake-up radios
National audienceWake-up Radios (WuRs) represent one of the most promising solutions for allowing an ultra-low power consumption in wireless sensor networks. However, WuRs have several limitations such as low sensitivity, inducing a miss-interpret of the wake-up signal, and thus a performance degradation of the whole system. This work introduces the use of minimum energy coding in order to enhance the WuR reliability while being energy efficient. The decoding is implemented on the micro-controller of the used WuR platform. It is shown, by combining analytical models and experimental measurements, an enhancement on the reliability up to 22% and a total energy saving of 42% while applying minimum energy coding.Les Wake-up Radios (WuR) sont une des solutions les plus prometteuses pour permettre une consommation d'énergie ultra faible dans les réseaux de capteurs sans fil. Cependant, les WuR ont plusieurs limitations telles que leur faible sensibilité, induisant une mauvaise réception du signal de réveil, et donc une dégradation des performances de l'ensemble du systÚme. Ce travail introduit l'utilisation d'un codage à minimum d'énergie afin d'améliorer la fiabilité des WuR tout en étant économe en énergie. Le décodage est implémenté sur le micro-contrÎleur faible consommation de la WuR utilisée. Il est démontré, en combinant des modÚles analytiques et des mesures expérimentales, une amélioration de la fiabilité jusqu'à 22% et une économie d'énergie totale de 42% lorsque le codage à minimum d'énergie est utilisé
The revenge of asynchronous protocols: Wake-up Radio-based Multi-hop Multi-channel MAC protocol for WSN
International audienceSynchronized MAC protocols are now considered as the ultimate solution to access the medium in wireless sensor networks. They guarantee both high throughout and constant latency and achieve reasonable energy consumption performance. However, synchronization is achieved at the cost of a complex framework with low flexibility on its parameters that is not suitable for some network topologies or application requirements. By contrast, asynchronous MAC protocols are versatile by nature but suffer from the tradeoff between energy consumption and latency. However, the addition of Wake-up Radio (WuR) can reduce the energy consumption of such protocols while maintaining very low latency thanks to its always-on feature and ultra-low power consumption. In this article, we present WuR- based Multi-hop Multi-channel (W2M), an asynchronous MAC protocol for wireless sensor networks. We also provide a fair comparison with Time Synchronized Channel Hopping (TSCH) through an extensive simulation campaign based on Contiki-NG and Cooja. Our results show that in low traffic scenarios, W2M outperforms TSCH in reducing both the energy consumption and the latency (at least 68% of energy is saved), but at the cost of slightly lower reliability
Gestion d'énergie et conception de protocoles pour les réseaux IoT hétérogÚnes utilisant les wake-up radios
The Wake-up Radios (WuRs) are a new promising solution allowing asynchronous communications with ultra low power consumption and low latency. WuR is however a matter of tradeoffs since to reduce as much energy consumption comes at the cost of low sensitivity and thus short range communications. In this thesis, we propose to enhance the performances of the WuR by using an adequate channel coding. This channel coding is called minimum energy coding and allows to increase the sensitivity. We also propose an improved version of minimum energy coding for additional reduction in both energy consumption and latency. Improving the performance of only the device is not always sufficient. As several devices are deployed in a network to form a wireless sensor network, it is important to pay attention to the design of the MAC protocol in order to obtain additional gains in range and energy consumption. We propose in this thesis a novel MAC protocol that allows long range communications while being energy efficient by combining WuR and LoRa. Another technique allowing to increase the range has been proposed by integrating the WuRs in a multi-hop network. Finally, devices resilience is limited when the devices are battery powered. Energy harvesting, that converts energy from environmental sources, is a viable alternative to ensure sustainable operation and improve the quality of service of the network. We propose in this thesis an energy manager adapted to the heterogeneous architecture that combines WuR and LoRa.Les Wake-up Radios (WuRs) sont une nouvelle solution prometteuse permettant des communications asynchrones Ă trĂšs faible puissance de consommation et trĂšs faible latence. Cependant, lâutilisation des WuRs repose sur un compromis vu que la rĂ©duction de la consommation dâĂ©nergie engendre une rĂ©duction de la sensibilitĂ© et donc une courte portĂ©e de communication. Dans cette, thĂšse nous proposons dâamĂ©liorer les performances de la WuR en utilisant un codage de canal adĂ©quat. Ce codage de canal est appelĂ© "Minimum Energy Coding" et permet dâaugmenter la sensibilitĂ© de la WuR. Nous proposons aussi une version amĂ©liorĂ©e de minimum energy coding pour une rĂ©duction supplĂ©mentaire de lâĂ©nergie consommĂ©e et de la latence. Cependant, lâamĂ©lioration des performances du nĆud seul nâest pas toujours suffisante. Comme le nĆud est dĂ©ployĂ© dans un rĂ©seau pour former un rĂ©seau de capteurs sans fil, il est important de prendre en considĂ©ration le protocole MAC afin dâobtenir des gains supplĂ©mentaires en portĂ©e et en consommation dâĂ©nergie. Nous proposons dans cette thĂšse un nouveau protocole MAC permettant une communication longue portĂ©e tout en Ă©tant efficace en Ă©nergie en combinant WuR et LoRa. Une autre technique permettant dâaugmenter la portĂ©e a Ă©tĂ© proposĂ©e en intĂ©grant les WuRs dans un rĂ©seau multi-sauts. Enfin, la rĂ©silience des nĆuds est limitĂ©e lorsque les nĆuds sont alimentĂ©s par des batteries. La rĂ©cupĂ©ration dâĂ©nergie, qui utilise lâĂ©nergie prĂ©sente dans lâenvironnement, est une alternative pour assurer un fonctionnement durable et augmenter la qualitĂ© de service du rĂ©seau. Nous proposons dans cette thĂšse un gestionnaire d'Ă©nergie adaptĂ© Ă lâarchitecture de rĂ©seau hĂ©tĂ©rogĂšne combinant WuR et LoRa
Gestion d'énergie et conception de protocoles pour les réseaux IoT hétérogÚnes utilisant les wake-up radios
Les Wake-up Radios (WuRs) sont une nouvelle solution prometteuse permettant des communications asynchrones Ă trĂšs faible puissance de consommation et trĂšs faible latence. Cependant, lâutilisation des WuRs repose sur un compromis vu que la rĂ©duction de la consommation dâĂ©nergie engendre une rĂ©duction de la sensibilitĂ© et donc une courte portĂ©e de communication. Dans cette, thĂšse nous proposons dâamĂ©liorer les performances de la WuR en utilisant un codage de canal adĂ©quat. Ce codage de canal est appelĂ© "Minimum Energy Coding" et permet dâaugmenter la sensibilitĂ© de la WuR. Nous proposons aussi une version amĂ©liorĂ©e de minimum energy coding pour une rĂ©duction supplĂ©mentaire de lâĂ©nergie consommĂ©e et de la latence. Cependant, lâamĂ©lioration des performances du nĆud seul nâest pas toujours suffisante. Comme le nĆud est dĂ©ployĂ© dans un rĂ©seau pour former un rĂ©seau de capteurs sans fil, il est important de prendre en considĂ©ration le protocole MAC afin dâobtenir des gains supplĂ©mentaires en portĂ©e et en consommation dâĂ©nergie. Nous proposons dans cette thĂšse un nouveau protocole MAC permettant une communication longue portĂ©e tout en Ă©tant efficace en Ă©nergie en combinant WuR et LoRa. Une autre technique permettant dâaugmenter la portĂ©e a Ă©tĂ© proposĂ©e en intĂ©grant les WuRs dans un rĂ©seau multi-sauts. Enfin, la rĂ©silience des nĆuds est limitĂ©e lorsque les nĆuds sont alimentĂ©s par des batteries. La rĂ©cupĂ©ration dâĂ©nergie, qui utilise lâĂ©nergie prĂ©sente dans lâenvironnement, est une alternative pour assurer un fonctionnement durable et augmenter la qualitĂ© de service du rĂ©seau. Nous proposons dans cette thĂšse un gestionnaire d'Ă©nergie adaptĂ© Ă lâarchitecture de rĂ©seau hĂ©tĂ©rogĂšne combinant WuR et LoRa.The Wake-up Radios (WuRs) are a new promising solution allowing asynchronous communications with ultra low power consumption and low latency. WuR is however a matter of tradeoffs since to reduce as much energy consumption comes at the cost of low sensitivity and thus short range communications. In this thesis, we propose to enhance the performances of the WuR by using an adequate channel coding. This channel coding is called minimum energy coding and allows to increase the sensitivity. We also propose an improved version of minimum energy coding for additional reduction in both energy consumption and latency. Improving the performance of only the device is not always sufficient. As several devices are deployed in a network to form a wireless sensor network, it is important to pay attention to the design of the MAC protocol in order to obtain additional gains in range and energy consumption. We propose in this thesis a novel MAC protocol that allows long range communications while being energy efficient by combining WuR and LoRa. Another technique allowing to increase the range has been proposed by integrating the WuRs in a multi-hop network. Finally, devices resilience is limited when the devices are battery powered. Energy harvesting, that converts energy from environmental sources, is a viable alternative to ensure sustainable operation and improve the quality of service of the network. We propose in this thesis an energy manager adapted to the heterogeneous architecture that combines WuR and LoRa
Sélection opportuniste des cluster heads dans des réseaux hétérogÚnes basse consommation
International audienceLes objets connectĂ©s utilisant la norme LoRaWAN peuvent rĂ©duire leur consommation d'Ă©nergie en quittant leurĂ©tat de veille uniquement pour envoyer leurs donnĂ©es. Cependant, cette technique induit une latence forte de la liaison descendante qui n'est pas compatible avec les applications contraintes en latence comme le contrĂŽleĂ distance ou celles utilisant des actuateurs. Afin de surmonter ce compromis entre la consommation d'Ă©nergie et la latence, nous proposons dans cet article un protocole MAC exploitant une architecture de rĂ©seau hĂ©tĂ©rogĂšne composĂ©e de radio longue portĂ©e LoRaWAN et de radio courte portĂ©e utilisant la wake-up radioĂ trĂšs faible consommation. GrĂąceĂ cette nouvelle architecture de rĂ©seau et au protocole MAC appropriĂ©, la latence peutĂȘtre rĂ©duite tout en maintenant ou mĂȘme en augmentant l'efficacitĂ©Ă©nergĂ©tique. Pour un cluster composĂ© de dix noeuds, des gains simultanĂ©s de 3.33 et de 2.11 peuventĂȘtre obtenus respectivement en latence et en consommation d'Ă©nergie
Adaptive relaying for wireless sensor networks leveraging wake-up receiver
International audienceEnergy management is a perennial issue in the design of wireless sensor networks that require long-term sustainability. Radio transmissions being the main energy consuming tasks, adaptive transmission power and relaying protocols represent promising solutions to increase network lifetime. In this work, a novel MAC protocol leveraging emerging wake up receivers is proposed for multihop wireless sensor networks. It uses energy-based back-off mechanism to allow nodes to choose the best transmission schemes (relay or not) and corresponding transmission powers. The proposed approach has been implemented on a real hardware platform. Performance evaluation combining analytical models and microbenchmarks demonstrates a potential lifetime gain up to 1.7 when two relays are used