The Internet of Things(IoT)has witnessed a significant surge in adoption,particularly through the utilization of Wireless Sensor Networks(WSNs),which comprise small internet-connected devices.These deployments span va...The Internet of Things(IoT)has witnessed a significant surge in adoption,particularly through the utilization of Wireless Sensor Networks(WSNs),which comprise small internet-connected devices.These deployments span various environments and offer a multitude of benefits.However,the widespread use of battery-powered devices introduces challenges due to their limited hardware resources and communication capabilities.In response to this,the Internet Engineering Task Force(IETF)has developed the IPv6 Routing Protocol for Low-power and Lossy Networks(RPL)to address the unique requirements of such networks.Recognizing the critical role of RPL in maintaining high performance,this paper proposes a novel approach to optimizing power consumption.Specifically,it introduces a developed sensor motes topology integrated with a Radio Duty Cycling(RDC)mechanism aimed at minimizing power usage.Through rigorous analysis,the paper evaluates the power efficiency of this approach through several simulations conducted across different network topologies,including random,linear,tree,and elliptical topologies.Additionally,three distinct RDC mechanisms—CXMAC,ContikiMAC,and NullRDC—are investigated to assess their impact on power consumption.The findings of the study,based on a comprehensive and deep analysis of the simulated results,highlight the efficiency of ContikiMAC in power conservation.This research contributes valuable insights into enhancing the energy efficiency of RPL-based IoT networks,ultimately facilitating their widespread deployment and usability in diverse environments.展开更多
Wake-up radio (WuR) system is often presented as the best candidate for replacing traditional duty cycled Medium Access Control (MAC) protocols in Wireless Sensor Networks (WSNs). The Double Radio (DoRa) protocol is a...Wake-up radio (WuR) system is often presented as the best candidate for replacing traditional duty cycled Medium Access Control (MAC) protocols in Wireless Sensor Networks (WSNs). The Double Radio (DoRa) protocol is a new MAC protocol for in-band WuR system with addressing capabilities. While the DoRa protocol improves the WSNs energy efficiency, it still suffers from an overhearing problem when the WuR system is very often requested. The WuR wastes a noticeable amount of energy when overhearing to wake-up demand intended to other nodes, but it is neither measured nor solved in other works. In this paper, an adaptive duty-cycled DoRa (DC-DoRa) is then proposed to solve the overhearing problem. The primary concept of the work is to enable the WuR functionality before the node is addressed and to disable the WuR after the node sent data. Extensive simulations under OMNeT++ using real input parameters are then performed to show the significant energy-savings through the two protocols and the nearly suppression of overhearing with DC-DoRa. In fact, the mean power consumption is three-order below using the DoRa protocol compared to traditional MAC protocols. While overhearing can represent up to 93% of the WuR energy consumption with the DoRa protocol, it is reduced to only 1% with the DC-DoRa protocol.展开更多
Due to the usable frequency becomes more and more crowed, dynamic spectrum access （DSA） is a new hope to solve this problem. However, DSA in China requires a quantitative analysis of the current spectrum utilization...Due to the usable frequency becomes more and more crowed, dynamic spectrum access （DSA） is a new hope to solve this problem. However, DSA in China requires a quantitative analysis of the current spectrum utilization in frequency, temporal and spatial domains. In order to free the precious spectrum, spectrum regulation organizations must have a clear, detailed, up-to-date understanding of where, how and by whom spectrum is currently being used--such data is essential to sound policy decisions in the context of cognitive radio （CR）. In this paper, a concurrent spectrum occupancy measurement in south China was conducted to evaluate the practical spectrum occupancy with a digital wideband receiver covering from 20 MHz to 3 GHz. We also propose systemic spectrum measurement methodology, matrix format data storage, duty cycle （DC） evaluation metric and data mining process which can be a guideline for other researchers when they conduct the similar experiments. Quantitative analysis and characterization of the 4 different measurement locations are evaluated to promote the popularization of CR application in China. And a uniform Beta distribution channel occupancy model is also validated using real-scene measurement data. The experimental results demonstrate that there is a significant scope for license-exemption use of the released spectrum using CR technology.展开更多
文摘The Internet of Things(IoT)has witnessed a significant surge in adoption,particularly through the utilization of Wireless Sensor Networks(WSNs),which comprise small internet-connected devices.These deployments span various environments and offer a multitude of benefits.However,the widespread use of battery-powered devices introduces challenges due to their limited hardware resources and communication capabilities.In response to this,the Internet Engineering Task Force(IETF)has developed the IPv6 Routing Protocol for Low-power and Lossy Networks(RPL)to address the unique requirements of such networks.Recognizing the critical role of RPL in maintaining high performance,this paper proposes a novel approach to optimizing power consumption.Specifically,it introduces a developed sensor motes topology integrated with a Radio Duty Cycling(RDC)mechanism aimed at minimizing power usage.Through rigorous analysis,the paper evaluates the power efficiency of this approach through several simulations conducted across different network topologies,including random,linear,tree,and elliptical topologies.Additionally,three distinct RDC mechanisms—CXMAC,ContikiMAC,and NullRDC—are investigated to assess their impact on power consumption.The findings of the study,based on a comprehensive and deep analysis of the simulated results,highlight the efficiency of ContikiMAC in power conservation.This research contributes valuable insights into enhancing the energy efficiency of RPL-based IoT networks,ultimately facilitating their widespread deployment and usability in diverse environments.
文摘Wake-up radio (WuR) system is often presented as the best candidate for replacing traditional duty cycled Medium Access Control (MAC) protocols in Wireless Sensor Networks (WSNs). The Double Radio (DoRa) protocol is a new MAC protocol for in-band WuR system with addressing capabilities. While the DoRa protocol improves the WSNs energy efficiency, it still suffers from an overhearing problem when the WuR system is very often requested. The WuR wastes a noticeable amount of energy when overhearing to wake-up demand intended to other nodes, but it is neither measured nor solved in other works. In this paper, an adaptive duty-cycled DoRa (DC-DoRa) is then proposed to solve the overhearing problem. The primary concept of the work is to enable the WuR functionality before the node is addressed and to disable the WuR after the node sent data. Extensive simulations under OMNeT++ using real input parameters are then performed to show the significant energy-savings through the two protocols and the nearly suppression of overhearing with DC-DoRa. In fact, the mean power consumption is three-order below using the DoRa protocol compared to traditional MAC protocols. While overhearing can represent up to 93% of the WuR energy consumption with the DoRa protocol, it is reduced to only 1% with the DC-DoRa protocol.
基金sponsored by the National Basic Research Program of China (2011CB302900)Postgraduate Innovation Fund of R&S-BUPT 2011+1 种基金National Key Technology R&D Program of China(2012ZX03003006)Shenzhen Bureau of Trade and Industry(JC200903170458A, JC201006010739A)
文摘Due to the usable frequency becomes more and more crowed, dynamic spectrum access （DSA） is a new hope to solve this problem. However, DSA in China requires a quantitative analysis of the current spectrum utilization in frequency, temporal and spatial domains. In order to free the precious spectrum, spectrum regulation organizations must have a clear, detailed, up-to-date understanding of where, how and by whom spectrum is currently being used--such data is essential to sound policy decisions in the context of cognitive radio （CR）. In this paper, a concurrent spectrum occupancy measurement in south China was conducted to evaluate the practical spectrum occupancy with a digital wideband receiver covering from 20 MHz to 3 GHz. We also propose systemic spectrum measurement methodology, matrix format data storage, duty cycle （DC） evaluation metric and data mining process which can be a guideline for other researchers when they conduct the similar experiments. Quantitative analysis and characterization of the 4 different measurement locations are evaluated to promote the popularization of CR application in China. And a uniform Beta distribution channel occupancy model is also validated using real-scene measurement data. The experimental results demonstrate that there is a significant scope for license-exemption use of the released spectrum using CR technology.
