2021 International Wireless Communications and Mobile Computing (IWCMC)
Long Range Wide Area Network (LoRaWAN) introduces the Adaptive Data rate (ADR) mechanism [1] aimi... more Long Range Wide Area Network (LoRaWAN) introduces the Adaptive Data rate (ADR) mechanism [1] aiming to maximize both battery life of the end-devices and overall network capacity. ADR performs adaptive tuning of radio configurations of the nodes by adjusting bandwidth, spreading factor, coding rate and transmission power parameters whenever the signal quality changes. The ADR algorithm was established for stable radio channel environments and is not efficient when conditions dramatically change (e.g. mobility). So, we have previously proposed an Enhanced-ADR (E-ADR) [2] that deals mobile nodes in case of predefined mobility patterns. However, several Internet Of Thing (IoT) applications, such as smart cattle ranching in smart farms [3], require sensors travelling with unknown or undefined trajectories. So, this paper extends E-ADR to unknown mobility pattern. This E-ADR extension, called VHMM-based E-ADR, is based on a Variable order Hidden Markov Model (VHMM) to predict the node trajectory. It has been implemented on Waspmote SX1272 hardware platform. Experimental results show its high efficiency in terms of the packet loss rate (PLR) and the energy consumption.
Together with the CPU and the network, storage plays an essential role in the overall performance... more Together with the CPU and the network, storage plays an essential role in the overall performance of applications, especially in the context of big data applications, that can deal with enormous datasets. However, testbeds have scarce support for experiments involving storage performance. Experimenters can use the storage devices provided on the testbed directly, but (1) they might not provide the suitable performance characteristics for their experiments; (2) it might leave an uncontrolled bias over the experiments' results. In this paper, we explore the feasibility of using Linux's control groups to emulate I/O performance for testbed experiments. We then use it in the Distem emulator to create a customizable I/O experimental environment. Using Distem, we perform experiments on Hadoop to highlight the advantage of emulating I/O performance. Results obtained from a cluster of 25 nodes show how the performance of Hadoop changes according to emulated storage performance.
HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci-entific ... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et a ̀ la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. PMCMTP’s implementation (in nesC/TinyOS2.x) and Testbed for its operation validation
This poster introduces how eBPF is used as an experimental method to discover I/O issue of a clus... more This poster introduces how eBPF is used as an experimental method to discover I/O issue of a clustered MongoDB. We show how such a tracing method addresses the limitation of high-level evaluation where the focus is limited on high-level metrics.
In the era of Big Data & Clouds distributed databases such as NoSQL databases are taking their pl... more In the era of Big Data & Clouds distributed databases such as NoSQL databases are taking their places among the most used storage systems. Benchmarking could be used to evaluate NoSQL databases. However, most benchmarks such as YCSB focus on high-level metrics like the throughput for evaluating Cloud systems, including NoSQL databases. As a result, some low-level metrics, which give an idea about how the databases are efficient at performing their different operations and interacting with the operating system, could not be evaluated. For example, various internal behaviors such as how the data is accessed on disks are considered as black boxes since tools to analyze them are lacking. We focus on MongoDB and study its I/O system, as MongoDB has a good reputation and is located at the top of document-based NoSQL databases. Its flexible data model and its worthy integrated tools make it a very favorable choice for different kinds of applications. We designed generic tracing tools to st...
Proceedings of the 1st International Workshop on Mobilizing Health Information to Support Healthcare-related Knowledge Work, 2009
The Utra Wide Band physical layer specified by the IEEE 802.15.4a standard [1] presents numerous ... more The Utra Wide Band physical layer specified by the IEEE 802.15.4a standard [1] presents numerous advantages comparing with its original IEEE 802.15.4 standard, namely high accuracy positioning ability, high data rate up to 27 mbps, extended communication range, low power consumption and low complexity. Actually, many research and development activities focus on the design of UWB sensor nodes entities. However nodes interactions or network configuration are neglected. For that, we propose in this paper to investigate the use of UWB for large scale Wireless Hospital Sensor Networks (WHSNs) to benefit from the advantages offered by the UWB technology. This evolving networking paradigm promises to revolutionize healthcare by allowing inexpensive, non-invasive, pervasive and ubiquitous, ambulatory health monitoring. We present the design of new system architecture, based on IEEE 802.15.4a compliant sensors, suitable for health monitoring application in high dense hospital environment. The proposed system architecture is intended to support large-scale deployment and to improve the network performance in terms of energy efficiency, real-time guarantees and Quality-of-Service (QoS).
The IEEE 802.15.4 has been studied for its possible use to support networked control systems. A c... more The IEEE 802.15.4 has been studied for its possible use to support networked control systems. A careful management of the network resources allows the enhancement of the quality of control (QoC) of the controlled system. This can be achieved by a co-design approach to manage the interaction between the WNCS and the wireless network in order to online adapt the QoC. This approach allows control loops to have access to the communication medium according to the state of the controlled system meanwhile attempting to optimize the overall control performance. When the QoC of the controlled system is not sufficient, the quality of service of the network is adapted online. This adaptation is realized by modifying the macMinBE parameter of the MAC protocol of the IEEE 802.15.4. Moreover, an implementation way of this scheme using the IEEE 802.15.4 protocol is presented. Simulation results show that this approach improves the control performance.
2012 9th IEEE International Workshop on Factory Communication Systems, 2012
Existing low-power MAC protocols only provide low throughput because of the fixed low duty-cycle.... more Existing low-power MAC protocols only provide low throughput because of the fixed low duty-cycle. This often leads to poor performance when dealing with timeconstrained burst traffic. In this paper, we propose a new hybrid CSMA/TDMA MAC protocol, called Queue-MAC, that dynamically adapts the duty-cycle according to the current network traffic. The queue length of nodes is used as the network traffic indicator. When the traffic increases, the active CSMA period is accordingly extended by adding dynamic TDMA slots, allowing thus to efficiently handle burst traffic under real-time constraints. This protocol is implemented on the STM32W108 SOC chips and compared with both a fixed duty-cycle reference protocol and an optimized IEEE802.15.4 MAC protocol. Through extensive experimental measurements, we showed that our queuelength aware hybrid CSMA/TDMA MAC protocol largely outperforms the compared protocols. The proposed protocol can be easily implemented through slight adaptation of the IEEE802.15.4 standard. It presents an optimal bandwidth and energy allocation scheme according to the traffic to be carried. In fact, low-duty cycle, so low power consumption is preserved during light traffic load period, while high throughput is obtained during heavy burst load period.. 1
2015 IEEE World Conference on Factory Communication Systems (WFCS), 2015
Many WSN industrial applications impose requirements in terms of end to end delay. However, the e... more Many WSN industrial applications impose requirements in terms of end to end delay. However, the end to end delay estimation in WSNs is not a simple task because of the high dynamic of networks, the use of duty-cycled MAC protocols as well as the impact of the routing protocols. Markov-based modelling is an interesting approach to deal with this problem aiming to provide an analytical model useful for understanding protocol's behavior and to estimate the end to end delay, among other performance parameters. However, existing Markov-based analytic models abstract the reality simplifying the analysis and thus resulting models are not accurate enough for estimating the end to end delay. Furthermore, establishing an accurate Markov model using classic approaches is very difficult considering the highly dynamic behavior of the sensor nodes. In this paper, we propose a novel approach to obtain the Markov chain model of sensor nodes by means of Process Mining techniques through the code execution trace. End to end delay is then computed based on this Markov chain. Experimentations were done using IoT-LAB testbed platform. Comparisons in terms of delay are presented for two different metrics of the RPL protocol (hop count and ETX).
Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, 2010
Providing service differentiation in wireless sensor networks while proposing simple and highly s... more Providing service differentiation in wireless sensor networks while proposing simple and highly scalable solution is a challenging problem. We retain the use of CSMA/CA as access protocol because of its simplicity, versatility and good scalability properties. We developed CoSenS on the top of it to address its weaknesses while facilitating the implementation of scheduling policies. In this article, we propose a simple and scalable service differentiation solution; we implement fixed priority and earliest deadline first on the top of CoSenS. The simulation analysis shows that our solution greatly enhances end-to-end delay, reliability and deadline meet ratio for urgent traffic while not degrading best effort traffic compared to IEEE 802.15.4 original protocol and IEEE 802.15.4 implementing these scheduling policies.
2008 IEEE International Workshop on Factory Communication Systems, 2008
A two-hop neighborhood information based routing protocol is proposed for real-time wireless sens... more A two-hop neighborhood information based routing protocol is proposed for real-time wireless sensor networks. The approach of mapping packet deadline to a velocity is adopted as SPEED; however, our routing decision is made based on the novel 2-hop velocity. Energyefficient probabilistic drop is embedded to enhance energy utilization efficiency while reducing packet deadline miss ratio. In case packet deadline requirement is not stringent, a new mechanism is included to release nodes which are frequently chosen as forwarders. Improvement on energy consumption balance throughout the network is observed. The true characteristics of physical and MAC layers are captured in the simulation. A real lossy link model is drawn from extensive experiments through Mica2 Motes. Simulation results show that the new protocol has achieved lower packet deadline miss ratio and higher energy efficiency. * This work was partially carried out during the tenure of an ERCIM "Alain Bensoussan" Fellowship Programme.
2013 IEEE International Conference on Sensing, Communications and Networking (SECON), 2013
Duty-cycling technique has been widely adopted in MAC protocols for wireless sensor networks to c... more Duty-cycling technique has been widely adopted in MAC protocols for wireless sensor networks to conserve energy. However, low duty-cycle also leads to limited throughput in most of existing solutions. In this paper, we propose iQueue-MAC to provide immediate yet energy-efficient throughput enhancement for dealing with burst or heavy traffic. Combined with CSMA/CA, iQueue-MAC makes use of queue length of each sensor node and allocates suitable TDMA slots to them for packets transmission. During light traffic period, no extra slots will be allocated; iQueue-MAC acts like other low duty-cycle MACs to conserve power. While in burst or heavy traffic period, iQueue-MAC senses the build up of packet queues and dynamically schedules adequate number of slots for packet transmission. We have implemented iQueue-MAC on STM32W108 chips that offer IEEE 802.15.4 standard communication. We set up several realworld experimental scenarios, including a 46 nodes multi-hop test-bed for simulating a general application, and conducted numerous experiments to evaluate iQueue-MAC, in comparison with other traffic adaptive duty-cycle protocols, such as multichannel version RI-MAC and CoSenS. Results clearly show that iQueue-MAC outperforms multi-channel version of RI-MAC and CoSenS in terms of packet delay and throughput.
IEEE 802.15.4 MAC protocol is the basis of many wireless sensor networks. Several studies have fo... more IEEE 802.15.4 MAC protocol is the basis of many wireless sensor networks. Several studies have focused on analyzing the MAC layer by means of mathematical models such as Markov chain in order to be able to estimate the protocol performance parameters. Normally, simulation is used in order to validate the accuracy of the model. Unfortunately, real life is not always as easy as we would expect and extra considerations must be taken into account when considering real scenarios. In this paper our objective is to determine the existing gap between theoretical models and measurement analysis in real scenarios. We compare results obtained by an a priori accurate mathematical framework modeling the slotted IEEE 802.15.4 MAC protocol with experimental results obtained in Telosb motes and an implementation of the protocol over TinyOS. Comparision was made in terms of average delay. We also present some implementation considerations that needs to be taken into account when designing theoretical models for evaluating the delay in WSN.
13th IFAC Symposium on Information Control Problems in Manufacturing, 2009
In this paper, the use of wireless sensor networks for networked control loop is analyzed. As the... more In this paper, the use of wireless sensor networks for networked control loop is analyzed. As the non beacon-enabled mode of IEEE 802.15.4/ZigBee does not ensure the stability for the control loop since non mechanism can prevent the perturbation coming from other applications sharing the same network, the quality of control has to be guaranteed for the control loop. Several possible solutions are investigated. The first one is the CSMA/CA with probabilistic priority by adjusting the minimum waiting time. The second one consists on a deterministic priority black burst mechanism in IEEE 802.15.4/ZigBee. The third one is the beacon-enabled mode using the Guaranteed Time Slot (GTS) mechanism.
2009 1st International Conference on Communications and Networking, ComNet 2009, 2009
This paper addresses a new prioritized multichannel multi-time slot MAC protocol (PMCMTP) for lar... more This paper addresses a new prioritized multichannel multi-time slot MAC protocol (PMCMTP) for large-scale WSNs especially for Ultra-Wide Band (UWB) based networks. To reduce the complexity of resource sharing, the global network is composed of a set of Personal Area Networks (PANs) or cells. According to available resource and PANs duty cycle, PMCMTP can dynamically assign several data channels per PAN and efficiently allocate time slots to each PAN's members. This significantly decreases delay and increases throughput. Through some simulations, we evaluate the performance of the proposed protocol. The results show that PMCMTP ensures an efficient and fair channels allocation between cells permitting, on the one hand, an enhancement of quality-of-service inside each PAN and, on the other hand, a maximization of channel utility.
2009 IEEE 34th Conference on Local Computer Networks, 2009
This article presents SCSP (for "Sleep Collect and Send Protocol") for wireless sensor networks, ... more This article presents SCSP (for "Sleep Collect and Send Protocol") for wireless sensor networks, a network-MAC cross layer design that resolves the inherent conflict between energy efficiency and throughput. The protocol uses in its MAC layer a new paradigm that we call "sleep, collect and send". The idea of SCSP is that a router sleeps for a given amount of time, wakes up and collects data from its children and other routers and then send them into a burst during a period of time that we call transmission period. In its network layer, the protocol uses a hierarchical tree structure as network architecture and a tree routing protocol. SCSP does not require synchronization between routers and dynamically calculates the sleep and collect periods according to the amount of incoming traffic. The protocol is implemented and simulated in OPNET simulator.
2014 IEEE International Conference on Distributed Computing in Sensor Systems, 2014
In the current protocol stack for Internet of Things in general and wireless sensor network in pa... more In the current protocol stack for Internet of Things in general and wireless sensor network in particular, many devices rely on the ContikiMAC protocol at their MAC layer. This protocol is widely used and enabled by default for several industrial environments and time sensitive monitoring and control applications. However, few work exists regarding the performance of this protocol because it lacks of an underlying theoretical model for analysing its performance. In this paper, we propose a novel approach relying on process mining technique that aims to obtain a Markov chain model for networks running the ContikiMAC protocol. In particular, we present a comprehensive specification of the protocol and a Markov chain model obtained through the analysis and instrumentation of its reference implementation. We used the obtained Markov chain to analyze and estimate the end to end delay distribution for a multi-hops transmission with static routing. The approach can also be extended to a wide range of protocols.
2021 International Wireless Communications and Mobile Computing (IWCMC)
Long Range Wide Area Network (LoRaWAN) introduces the Adaptive Data rate (ADR) mechanism [1] aimi... more Long Range Wide Area Network (LoRaWAN) introduces the Adaptive Data rate (ADR) mechanism [1] aiming to maximize both battery life of the end-devices and overall network capacity. ADR performs adaptive tuning of radio configurations of the nodes by adjusting bandwidth, spreading factor, coding rate and transmission power parameters whenever the signal quality changes. The ADR algorithm was established for stable radio channel environments and is not efficient when conditions dramatically change (e.g. mobility). So, we have previously proposed an Enhanced-ADR (E-ADR) [2] that deals mobile nodes in case of predefined mobility patterns. However, several Internet Of Thing (IoT) applications, such as smart cattle ranching in smart farms [3], require sensors travelling with unknown or undefined trajectories. So, this paper extends E-ADR to unknown mobility pattern. This E-ADR extension, called VHMM-based E-ADR, is based on a Variable order Hidden Markov Model (VHMM) to predict the node trajectory. It has been implemented on Waspmote SX1272 hardware platform. Experimental results show its high efficiency in terms of the packet loss rate (PLR) and the energy consumption.
Together with the CPU and the network, storage plays an essential role in the overall performance... more Together with the CPU and the network, storage plays an essential role in the overall performance of applications, especially in the context of big data applications, that can deal with enormous datasets. However, testbeds have scarce support for experiments involving storage performance. Experimenters can use the storage devices provided on the testbed directly, but (1) they might not provide the suitable performance characteristics for their experiments; (2) it might leave an uncontrolled bias over the experiments' results. In this paper, we explore the feasibility of using Linux's control groups to emulate I/O performance for testbed experiments. We then use it in the Distem emulator to create a customizable I/O experimental environment. Using Distem, we perform experiments on Hadoop to highlight the advantage of emulating I/O performance. Results obtained from a cluster of 25 nodes show how the performance of Hadoop changes according to emulated storage performance.
HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci-entific ... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et a ̀ la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. PMCMTP’s implementation (in nesC/TinyOS2.x) and Testbed for its operation validation
This poster introduces how eBPF is used as an experimental method to discover I/O issue of a clus... more This poster introduces how eBPF is used as an experimental method to discover I/O issue of a clustered MongoDB. We show how such a tracing method addresses the limitation of high-level evaluation where the focus is limited on high-level metrics.
In the era of Big Data & Clouds distributed databases such as NoSQL databases are taking their pl... more In the era of Big Data & Clouds distributed databases such as NoSQL databases are taking their places among the most used storage systems. Benchmarking could be used to evaluate NoSQL databases. However, most benchmarks such as YCSB focus on high-level metrics like the throughput for evaluating Cloud systems, including NoSQL databases. As a result, some low-level metrics, which give an idea about how the databases are efficient at performing their different operations and interacting with the operating system, could not be evaluated. For example, various internal behaviors such as how the data is accessed on disks are considered as black boxes since tools to analyze them are lacking. We focus on MongoDB and study its I/O system, as MongoDB has a good reputation and is located at the top of document-based NoSQL databases. Its flexible data model and its worthy integrated tools make it a very favorable choice for different kinds of applications. We designed generic tracing tools to st...
Proceedings of the 1st International Workshop on Mobilizing Health Information to Support Healthcare-related Knowledge Work, 2009
The Utra Wide Band physical layer specified by the IEEE 802.15.4a standard [1] presents numerous ... more The Utra Wide Band physical layer specified by the IEEE 802.15.4a standard [1] presents numerous advantages comparing with its original IEEE 802.15.4 standard, namely high accuracy positioning ability, high data rate up to 27 mbps, extended communication range, low power consumption and low complexity. Actually, many research and development activities focus on the design of UWB sensor nodes entities. However nodes interactions or network configuration are neglected. For that, we propose in this paper to investigate the use of UWB for large scale Wireless Hospital Sensor Networks (WHSNs) to benefit from the advantages offered by the UWB technology. This evolving networking paradigm promises to revolutionize healthcare by allowing inexpensive, non-invasive, pervasive and ubiquitous, ambulatory health monitoring. We present the design of new system architecture, based on IEEE 802.15.4a compliant sensors, suitable for health monitoring application in high dense hospital environment. The proposed system architecture is intended to support large-scale deployment and to improve the network performance in terms of energy efficiency, real-time guarantees and Quality-of-Service (QoS).
The IEEE 802.15.4 has been studied for its possible use to support networked control systems. A c... more The IEEE 802.15.4 has been studied for its possible use to support networked control systems. A careful management of the network resources allows the enhancement of the quality of control (QoC) of the controlled system. This can be achieved by a co-design approach to manage the interaction between the WNCS and the wireless network in order to online adapt the QoC. This approach allows control loops to have access to the communication medium according to the state of the controlled system meanwhile attempting to optimize the overall control performance. When the QoC of the controlled system is not sufficient, the quality of service of the network is adapted online. This adaptation is realized by modifying the macMinBE parameter of the MAC protocol of the IEEE 802.15.4. Moreover, an implementation way of this scheme using the IEEE 802.15.4 protocol is presented. Simulation results show that this approach improves the control performance.
2012 9th IEEE International Workshop on Factory Communication Systems, 2012
Existing low-power MAC protocols only provide low throughput because of the fixed low duty-cycle.... more Existing low-power MAC protocols only provide low throughput because of the fixed low duty-cycle. This often leads to poor performance when dealing with timeconstrained burst traffic. In this paper, we propose a new hybrid CSMA/TDMA MAC protocol, called Queue-MAC, that dynamically adapts the duty-cycle according to the current network traffic. The queue length of nodes is used as the network traffic indicator. When the traffic increases, the active CSMA period is accordingly extended by adding dynamic TDMA slots, allowing thus to efficiently handle burst traffic under real-time constraints. This protocol is implemented on the STM32W108 SOC chips and compared with both a fixed duty-cycle reference protocol and an optimized IEEE802.15.4 MAC protocol. Through extensive experimental measurements, we showed that our queuelength aware hybrid CSMA/TDMA MAC protocol largely outperforms the compared protocols. The proposed protocol can be easily implemented through slight adaptation of the IEEE802.15.4 standard. It presents an optimal bandwidth and energy allocation scheme according to the traffic to be carried. In fact, low-duty cycle, so low power consumption is preserved during light traffic load period, while high throughput is obtained during heavy burst load period.. 1
2015 IEEE World Conference on Factory Communication Systems (WFCS), 2015
Many WSN industrial applications impose requirements in terms of end to end delay. However, the e... more Many WSN industrial applications impose requirements in terms of end to end delay. However, the end to end delay estimation in WSNs is not a simple task because of the high dynamic of networks, the use of duty-cycled MAC protocols as well as the impact of the routing protocols. Markov-based modelling is an interesting approach to deal with this problem aiming to provide an analytical model useful for understanding protocol's behavior and to estimate the end to end delay, among other performance parameters. However, existing Markov-based analytic models abstract the reality simplifying the analysis and thus resulting models are not accurate enough for estimating the end to end delay. Furthermore, establishing an accurate Markov model using classic approaches is very difficult considering the highly dynamic behavior of the sensor nodes. In this paper, we propose a novel approach to obtain the Markov chain model of sensor nodes by means of Process Mining techniques through the code execution trace. End to end delay is then computed based on this Markov chain. Experimentations were done using IoT-LAB testbed platform. Comparisons in terms of delay are presented for two different metrics of the RPL protocol (hop count and ETX).
Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, 2010
Providing service differentiation in wireless sensor networks while proposing simple and highly s... more Providing service differentiation in wireless sensor networks while proposing simple and highly scalable solution is a challenging problem. We retain the use of CSMA/CA as access protocol because of its simplicity, versatility and good scalability properties. We developed CoSenS on the top of it to address its weaknesses while facilitating the implementation of scheduling policies. In this article, we propose a simple and scalable service differentiation solution; we implement fixed priority and earliest deadline first on the top of CoSenS. The simulation analysis shows that our solution greatly enhances end-to-end delay, reliability and deadline meet ratio for urgent traffic while not degrading best effort traffic compared to IEEE 802.15.4 original protocol and IEEE 802.15.4 implementing these scheduling policies.
2008 IEEE International Workshop on Factory Communication Systems, 2008
A two-hop neighborhood information based routing protocol is proposed for real-time wireless sens... more A two-hop neighborhood information based routing protocol is proposed for real-time wireless sensor networks. The approach of mapping packet deadline to a velocity is adopted as SPEED; however, our routing decision is made based on the novel 2-hop velocity. Energyefficient probabilistic drop is embedded to enhance energy utilization efficiency while reducing packet deadline miss ratio. In case packet deadline requirement is not stringent, a new mechanism is included to release nodes which are frequently chosen as forwarders. Improvement on energy consumption balance throughout the network is observed. The true characteristics of physical and MAC layers are captured in the simulation. A real lossy link model is drawn from extensive experiments through Mica2 Motes. Simulation results show that the new protocol has achieved lower packet deadline miss ratio and higher energy efficiency. * This work was partially carried out during the tenure of an ERCIM "Alain Bensoussan" Fellowship Programme.
2013 IEEE International Conference on Sensing, Communications and Networking (SECON), 2013
Duty-cycling technique has been widely adopted in MAC protocols for wireless sensor networks to c... more Duty-cycling technique has been widely adopted in MAC protocols for wireless sensor networks to conserve energy. However, low duty-cycle also leads to limited throughput in most of existing solutions. In this paper, we propose iQueue-MAC to provide immediate yet energy-efficient throughput enhancement for dealing with burst or heavy traffic. Combined with CSMA/CA, iQueue-MAC makes use of queue length of each sensor node and allocates suitable TDMA slots to them for packets transmission. During light traffic period, no extra slots will be allocated; iQueue-MAC acts like other low duty-cycle MACs to conserve power. While in burst or heavy traffic period, iQueue-MAC senses the build up of packet queues and dynamically schedules adequate number of slots for packet transmission. We have implemented iQueue-MAC on STM32W108 chips that offer IEEE 802.15.4 standard communication. We set up several realworld experimental scenarios, including a 46 nodes multi-hop test-bed for simulating a general application, and conducted numerous experiments to evaluate iQueue-MAC, in comparison with other traffic adaptive duty-cycle protocols, such as multichannel version RI-MAC and CoSenS. Results clearly show that iQueue-MAC outperforms multi-channel version of RI-MAC and CoSenS in terms of packet delay and throughput.
IEEE 802.15.4 MAC protocol is the basis of many wireless sensor networks. Several studies have fo... more IEEE 802.15.4 MAC protocol is the basis of many wireless sensor networks. Several studies have focused on analyzing the MAC layer by means of mathematical models such as Markov chain in order to be able to estimate the protocol performance parameters. Normally, simulation is used in order to validate the accuracy of the model. Unfortunately, real life is not always as easy as we would expect and extra considerations must be taken into account when considering real scenarios. In this paper our objective is to determine the existing gap between theoretical models and measurement analysis in real scenarios. We compare results obtained by an a priori accurate mathematical framework modeling the slotted IEEE 802.15.4 MAC protocol with experimental results obtained in Telosb motes and an implementation of the protocol over TinyOS. Comparision was made in terms of average delay. We also present some implementation considerations that needs to be taken into account when designing theoretical models for evaluating the delay in WSN.
13th IFAC Symposium on Information Control Problems in Manufacturing, 2009
In this paper, the use of wireless sensor networks for networked control loop is analyzed. As the... more In this paper, the use of wireless sensor networks for networked control loop is analyzed. As the non beacon-enabled mode of IEEE 802.15.4/ZigBee does not ensure the stability for the control loop since non mechanism can prevent the perturbation coming from other applications sharing the same network, the quality of control has to be guaranteed for the control loop. Several possible solutions are investigated. The first one is the CSMA/CA with probabilistic priority by adjusting the minimum waiting time. The second one consists on a deterministic priority black burst mechanism in IEEE 802.15.4/ZigBee. The third one is the beacon-enabled mode using the Guaranteed Time Slot (GTS) mechanism.
2009 1st International Conference on Communications and Networking, ComNet 2009, 2009
This paper addresses a new prioritized multichannel multi-time slot MAC protocol (PMCMTP) for lar... more This paper addresses a new prioritized multichannel multi-time slot MAC protocol (PMCMTP) for large-scale WSNs especially for Ultra-Wide Band (UWB) based networks. To reduce the complexity of resource sharing, the global network is composed of a set of Personal Area Networks (PANs) or cells. According to available resource and PANs duty cycle, PMCMTP can dynamically assign several data channels per PAN and efficiently allocate time slots to each PAN's members. This significantly decreases delay and increases throughput. Through some simulations, we evaluate the performance of the proposed protocol. The results show that PMCMTP ensures an efficient and fair channels allocation between cells permitting, on the one hand, an enhancement of quality-of-service inside each PAN and, on the other hand, a maximization of channel utility.
2009 IEEE 34th Conference on Local Computer Networks, 2009
This article presents SCSP (for "Sleep Collect and Send Protocol") for wireless sensor networks, ... more This article presents SCSP (for "Sleep Collect and Send Protocol") for wireless sensor networks, a network-MAC cross layer design that resolves the inherent conflict between energy efficiency and throughput. The protocol uses in its MAC layer a new paradigm that we call "sleep, collect and send". The idea of SCSP is that a router sleeps for a given amount of time, wakes up and collects data from its children and other routers and then send them into a burst during a period of time that we call transmission period. In its network layer, the protocol uses a hierarchical tree structure as network architecture and a tree routing protocol. SCSP does not require synchronization between routers and dynamically calculates the sleep and collect periods according to the amount of incoming traffic. The protocol is implemented and simulated in OPNET simulator.
2014 IEEE International Conference on Distributed Computing in Sensor Systems, 2014
In the current protocol stack for Internet of Things in general and wireless sensor network in pa... more In the current protocol stack for Internet of Things in general and wireless sensor network in particular, many devices rely on the ContikiMAC protocol at their MAC layer. This protocol is widely used and enabled by default for several industrial environments and time sensitive monitoring and control applications. However, few work exists regarding the performance of this protocol because it lacks of an underlying theoretical model for analysing its performance. In this paper, we propose a novel approach relying on process mining technique that aims to obtain a Markov chain model for networks running the ContikiMAC protocol. In particular, we present a comprehensive specification of the protocol and a Markov chain model obtained through the analysis and instrumentation of its reference implementation. We used the obtained Markov chain to analyze and estimate the end to end delay distribution for a multi-hops transmission with static routing. The approach can also be extended to a wide range of protocols.
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Papers by Ye-Qiong Song