Wireless sensor network(WSN) is a typical kind of low-power and lossy network,in where ARQ(Automatic Repeat reQuest)schemes are often used to improve packets reliability.However,the ARQ related packets may incur signi...Wireless sensor network(WSN) is a typical kind of low-power and lossy network,in where ARQ(Automatic Repeat reQuest)schemes are often used to improve packets reliability.However,the ARQ related packets may incur significant load and consume more energy.This paper proposes a novel energy efficient ARQ protocol called ARQ+,which uses the nearest-first scheme and NAK aggregation scheme to reduce the amount and transmission hops of the ARQ related packets.Consequently,the energy consumption is significantly decreased.Theoretical analyses of ARQ+ on energy consumption,packet arrive ratio and latency are provided.Performance improvement of ARQ+ is validated by extensive simulations.They both show that ARQ+ has satisfactory energy efficiency,good packets arriving ratio and reasonable average packet delay comparing to traditional ARQ schemes.展开更多
The smart grid has caught great attentions in recent years, which is poised to transform a centralized, producer-controlled network to a decentralized, consumer- interactive network that＇s supported by fine-grained m...The smart grid has caught great attentions in recent years, which is poised to transform a centralized, producer-controlled network to a decentralized, consumer- interactive network that＇s supported by fine-grained monitoring. Large-scale WSNs （Wireless Sensor Networks） have been considered one of the very promising technologies to support the implementation of smart grid. WSNs are applied in almost every aspect of smart grid, including power generation, power transmission, power distribution, power utilization and power dispatch, and the data query processing of ＇WSNs in power grid＇ become an hotspot issue due to the amount of data of power grid is very large and the requirement of response time is very high. To meet the demands, top-k query processing is a good choice, which performs the cooperative query by aggregating the database objects＇ degree of match for each different query predicate and returning the best k matching objects. In this paper, a framework that can effectively apply top-k query to wireless sensor network in smart grid is proposed, which is based on the cluster-topology sensor network. In the new method, local indices are used to optimize the necessary query routing and process intermediate results inside the cluster to cut down the data traffic, and the hierarchical join query is executed based on the local results.Besides, top-k query results are verified by the clean-up process, and two schemes are taken to deal with the problem of node＇s dynamicity, which further reduce communication cost. Case studies and experimental results show that our algorithm has outperformed the current existing one with higher quality results and better efficiently.展开更多
基金partly supported by the National Key Technology Research and Development Program of China under Grant No.2011BAK12B02the National Natural Science Foundation of China under Grant No.61104042+2 种基金the National S&T Major Project of China under Grant No.2010ZX03005-003the Program for New Century Excellent Talents in University(NCET-10-0294),Chinathe National Natural Science Foundation of China under Grant No.60832007
文摘Wireless sensor network(WSN) is a typical kind of low-power and lossy network,in where ARQ(Automatic Repeat reQuest)schemes are often used to improve packets reliability.However,the ARQ related packets may incur significant load and consume more energy.This paper proposes a novel energy efficient ARQ protocol called ARQ+,which uses the nearest-first scheme and NAK aggregation scheme to reduce the amount and transmission hops of the ARQ related packets.Consequently,the energy consumption is significantly decreased.Theoretical analyses of ARQ+ on energy consumption,packet arrive ratio and latency are provided.Performance improvement of ARQ+ is validated by extensive simulations.They both show that ARQ+ has satisfactory energy efficiency,good packets arriving ratio and reasonable average packet delay comparing to traditional ARQ schemes.
文摘The smart grid has caught great attentions in recent years, which is poised to transform a centralized, producer-controlled network to a decentralized, consumer- interactive network that＇s supported by fine-grained monitoring. Large-scale WSNs （Wireless Sensor Networks） have been considered one of the very promising technologies to support the implementation of smart grid. WSNs are applied in almost every aspect of smart grid, including power generation, power transmission, power distribution, power utilization and power dispatch, and the data query processing of ＇WSNs in power grid＇ become an hotspot issue due to the amount of data of power grid is very large and the requirement of response time is very high. To meet the demands, top-k query processing is a good choice, which performs the cooperative query by aggregating the database objects＇ degree of match for each different query predicate and returning the best k matching objects. In this paper, a framework that can effectively apply top-k query to wireless sensor network in smart grid is proposed, which is based on the cluster-topology sensor network. In the new method, local indices are used to optimize the necessary query routing and process intermediate results inside the cluster to cut down the data traffic, and the hierarchical join query is executed based on the local results.Besides, top-k query results are verified by the clean-up process, and two schemes are taken to deal with the problem of node＇s dynamicity, which further reduce communication cost. Case studies and experimental results show that our algorithm has outperformed the current existing one with higher quality results and better efficiently.
