The Experts below are selected from a list of 17283 Experts worldwide ranked by ideXlab platform
Meng Zheng - One of the best experts on this subject based on the ideXlab platform.
-
Relay Node placement in wireless sensor networks from theory to practice
IEEE Transactions on Mobile Computing, 2021Co-Authors: Wei Liang, Meng Zheng, Longxiang LuoAbstract:The increasingly wide utilization of Wireless Sensor Networks (WSNs) in industrial applications outstands the significance of the Delay Constrained Relay Node Placement (DCRNP) problem. The unreliable and unpredictable wireless links in WSNs may lead existing algorithms to fail in practice. Therefore, we first conduct extensive real-world deployments under the guidance of existing algorithms to evaluate their performance and to gain some insights for designing practical deployment algorithms. Based on the experiences learned from practical experiments, we first devise a Set-Covering-based Algorithm (SCA) which figures out the DCRNP problem while trying to make the quality of each link better than a given threshold. As our experiments also show that the fault-tolerant topology can significantly improve network reliability, we then design a $k$ -Set-Covering-based Algorithm ( $k$ SCA) to build fault-tolerant WSNs based on the methodology of SCA. Furthermore, the elaborate analysis proves that both SCA and $k$ SCA are polynomial-time algorithms, and their approximation ratios are $\text{O}(\ln n)$ and $\text{O}(\lg n)$ , respectively, where $n$ is the number of sensor Nodes. Finally, extensive experiments are performed under the guidance of SCA and $k$ SCA to demonstrate the effectivenesses of these two algorithms.
-
Relay Node placement in wireless sensor networks from theory to practice
IEEE Transactions on Mobile Computing, 2021Co-Authors: Wei Liang, Meng Zheng, Longxiang LuoAbstract:The increasingly wide utilization of Wireless Sensor Networks (WSNs) in industrial applications outstands the significance of the Delay Constrained Relay Node Placement (DCRNP) problem. Existing algorithms to the DCRNP problem are designed based on the ideal geometric disk wireless channel model, and no real-world deployments are performed to verify the effectiveness of these algorithms. However, the unreliable and unpredictable wireless links in WSNs may lead these algorithms to fail in practice. Therefore, we first conduct extensive real-world deployments under the guidance of existing algorithms to evaluate their performance and to gain some insights for designing practical deployment algorithms. The results exhibit that the WSNs built by existing algorithms have a favorable performance in end-to-end delay but a poor performance in reliability, which is mainly due to the lack of methods ensuring high-quality links. To this end, we first devise a Set-Covering-based Algorithm (SCA) which figures out the DCRNP problem while ensuring the quality of each link better than a given threshold. As our experiments also show that the fault-tolerant topology can significantly improve network reliability, we then design a $k$ k -Set-Covering-based Algorithm ( $k$ k SCA) to build fault-tolerant WSNs based on the methodology of SCA. Furthermore, the elaborate analysis proves that both SCA and $k$ k SCA are polynomial-time algorithms, and their approximation ratios are both O( $\ln n$ ln n ), where $n$ n is the number of sensor Nodes. Finally, extensive experiments are performed under the guidance of SCA and $k$ k SCA to demonstrate the effectiveness of these two algorithms.
-
delay constrained Relay Node placement in two tiered wireless sensor networks a set covering based algorithm
Journal of Network and Computer Applications, 2017Co-Authors: Wei Liang, Meng ZhengAbstract:Abstract As Wireless Sensor Networks (WSNs) are widely used in time-critical applications, e.g., factory automation and smart grid, the importance of Delay Constrained Relay Node Placement (DCRNP) problem is becoming increasingly noticeable. Considering the benefits in terms of energy efficiency and scalability brought by the two-tiered topology, this paper studies the DCRNP problem in two-tiered WSNs. To address the NP-hardness, a Two-phase Set-Covering-based Algorithm (TSCA) is proposed to approximately solve this problem. To be specific, in the first phase, a Connectivity-aware Covering Algorithm (CCA) places Relay Nodes (RNs) to fully cover distributed sensor Nodes with respect to delay constraints, and meanwhile CCA tries to reduce the number of connected components in the topology constructed in this phase so as to save the RNs deployed to build network connectivity. In the second phase, the network connectivity is built in obedience to delay constraints by a Set-Covering-based Algorithm (SCA) through an iterative manner, which formulates the deployment of RNs at each iteration as the set covering problem and solves this problem using a classic set covering algorithm. In addition, the elaborated analysis of time complexity and approximation ratio of the proposed algorithms is given out. Finally, extensive simulations demonstrate that TSCA can significantly save deployed RNs in comparison to existing algorithms.
-
set covering based algorithm for delay constrained Relay Node placement in wireless sensor networks
International Conference on Communications, 2016Co-Authors: Wei Liang, Meng ZhengAbstract:As Wireless Sensor Networks (WSNs) are widely used in time-critical applications, e.g., factory automation and smart grid, the importance of Delay Constrained Relay Node Placement (DCRNP) problem is becoming increasingly noticeable. This paper proposes a Set-Covering-based Approximation (SCA) algorithm to solve the DCRNP problem. The SCA deploys Relay Nodes by levels from the sink to sensor Nodes. To avoid the limitation suffering by existing algorithms and ensure a polynomial time complexity, SCA employs a novel approach to formulate the deployment of Relay Nodes at each level as the set covering problem subject to delay constraints, and based on the classic greedy-set-covering algorithm, a set of Relay Nodes are placed to connect the Nodes (sensor Nodes and Relay Nodes) that are already connected to the sink. Since delay constraints are met at each level, all the sensor Nodes will be connected to the sink via feasible paths fulfilling delay constraints. In addition, the elaborated analysis of the time complexity and the approximation ratio of the SCA algorithm is given out. Extensive simulations show that SCA can significantly save deployed Relay Nodes in comparison to existing algorithms.
-
a connectivity aware approximation algorithm for Relay Node placement in wireless sensor networks
IEEE Sensors Journal, 2016Co-Authors: Wei Liang, Meng Zheng, Hamid SharifAbstract:In two-tiered wireless sensor networks (WSNs), Relay Node placement is one of the key factors impacting the network energy consumption and the system overhead. In this paper, a novel connectivity-aware approximation algorithm for Relay Node placement in the WSNs is proposed to offer a major step forward in saving system overhead. In particular, a unique local search approximation algorithm (LSAA) is introduced to solve the Relay Node single cover (RNSC) problem. In this proposed LSAA approach, the sensor Nodes are allocated into groups and then a local set cover (SC) for each group is achieved by a local search algorithm. The union set of all the local SCs constitutes a SC of the RNSC problem. The approximation ratio and the time complexity of the LSAA are analyzed by rigorous proof. In addition, the LSAA approach has been extended to solve the Relay Node double cover problem. Then, a Relay location selection algorithm (RLSA) is proposed to utilize the resulting SC from the LSAA in combining RLSA with the minimum spanning tree heuristic to build the high-tier connectivity. As the RLSA searches for a nearest location to the sink Node for each Relay Node, the high-tier network built by the RLSA becomes denser than that by existing works. As a result, the number of added Relay Nodes for building the connectivity of the high-tier WSN can be significantly saved. Simulation results clearly demonstrate that the proposed LSAA outperforms the approaches reported in literature and the RLSA-based algorithm can noticeably save Relay Nodes newly deployed for the high-tier connectivity.
Wei Liang - One of the best experts on this subject based on the ideXlab platform.
-
Relay Node placement in wireless sensor networks from theory to practice
IEEE Transactions on Mobile Computing, 2021Co-Authors: Wei Liang, Meng Zheng, Longxiang LuoAbstract:The increasingly wide utilization of Wireless Sensor Networks (WSNs) in industrial applications outstands the significance of the Delay Constrained Relay Node Placement (DCRNP) problem. The unreliable and unpredictable wireless links in WSNs may lead existing algorithms to fail in practice. Therefore, we first conduct extensive real-world deployments under the guidance of existing algorithms to evaluate their performance and to gain some insights for designing practical deployment algorithms. Based on the experiences learned from practical experiments, we first devise a Set-Covering-based Algorithm (SCA) which figures out the DCRNP problem while trying to make the quality of each link better than a given threshold. As our experiments also show that the fault-tolerant topology can significantly improve network reliability, we then design a $k$ -Set-Covering-based Algorithm ( $k$ SCA) to build fault-tolerant WSNs based on the methodology of SCA. Furthermore, the elaborate analysis proves that both SCA and $k$ SCA are polynomial-time algorithms, and their approximation ratios are $\text{O}(\ln n)$ and $\text{O}(\lg n)$ , respectively, where $n$ is the number of sensor Nodes. Finally, extensive experiments are performed under the guidance of SCA and $k$ SCA to demonstrate the effectivenesses of these two algorithms.
-
Relay Node placement in wireless sensor networks from theory to practice
IEEE Transactions on Mobile Computing, 2021Co-Authors: Wei Liang, Meng Zheng, Longxiang LuoAbstract:The increasingly wide utilization of Wireless Sensor Networks (WSNs) in industrial applications outstands the significance of the Delay Constrained Relay Node Placement (DCRNP) problem. Existing algorithms to the DCRNP problem are designed based on the ideal geometric disk wireless channel model, and no real-world deployments are performed to verify the effectiveness of these algorithms. However, the unreliable and unpredictable wireless links in WSNs may lead these algorithms to fail in practice. Therefore, we first conduct extensive real-world deployments under the guidance of existing algorithms to evaluate their performance and to gain some insights for designing practical deployment algorithms. The results exhibit that the WSNs built by existing algorithms have a favorable performance in end-to-end delay but a poor performance in reliability, which is mainly due to the lack of methods ensuring high-quality links. To this end, we first devise a Set-Covering-based Algorithm (SCA) which figures out the DCRNP problem while ensuring the quality of each link better than a given threshold. As our experiments also show that the fault-tolerant topology can significantly improve network reliability, we then design a $k$ k -Set-Covering-based Algorithm ( $k$ k SCA) to build fault-tolerant WSNs based on the methodology of SCA. Furthermore, the elaborate analysis proves that both SCA and $k$ k SCA are polynomial-time algorithms, and their approximation ratios are both O( $\ln n$ ln n ), where $n$ n is the number of sensor Nodes. Finally, extensive experiments are performed under the guidance of SCA and $k$ k SCA to demonstrate the effectiveness of these two algorithms.
-
delay constrained Relay Node placement in two tiered wireless sensor networks a set covering based algorithm
Journal of Network and Computer Applications, 2017Co-Authors: Wei Liang, Meng ZhengAbstract:Abstract As Wireless Sensor Networks (WSNs) are widely used in time-critical applications, e.g., factory automation and smart grid, the importance of Delay Constrained Relay Node Placement (DCRNP) problem is becoming increasingly noticeable. Considering the benefits in terms of energy efficiency and scalability brought by the two-tiered topology, this paper studies the DCRNP problem in two-tiered WSNs. To address the NP-hardness, a Two-phase Set-Covering-based Algorithm (TSCA) is proposed to approximately solve this problem. To be specific, in the first phase, a Connectivity-aware Covering Algorithm (CCA) places Relay Nodes (RNs) to fully cover distributed sensor Nodes with respect to delay constraints, and meanwhile CCA tries to reduce the number of connected components in the topology constructed in this phase so as to save the RNs deployed to build network connectivity. In the second phase, the network connectivity is built in obedience to delay constraints by a Set-Covering-based Algorithm (SCA) through an iterative manner, which formulates the deployment of RNs at each iteration as the set covering problem and solves this problem using a classic set covering algorithm. In addition, the elaborated analysis of time complexity and approximation ratio of the proposed algorithms is given out. Finally, extensive simulations demonstrate that TSCA can significantly save deployed RNs in comparison to existing algorithms.
-
set covering based algorithm for delay constrained Relay Node placement in wireless sensor networks
International Conference on Communications, 2016Co-Authors: Wei Liang, Meng ZhengAbstract:As Wireless Sensor Networks (WSNs) are widely used in time-critical applications, e.g., factory automation and smart grid, the importance of Delay Constrained Relay Node Placement (DCRNP) problem is becoming increasingly noticeable. This paper proposes a Set-Covering-based Approximation (SCA) algorithm to solve the DCRNP problem. The SCA deploys Relay Nodes by levels from the sink to sensor Nodes. To avoid the limitation suffering by existing algorithms and ensure a polynomial time complexity, SCA employs a novel approach to formulate the deployment of Relay Nodes at each level as the set covering problem subject to delay constraints, and based on the classic greedy-set-covering algorithm, a set of Relay Nodes are placed to connect the Nodes (sensor Nodes and Relay Nodes) that are already connected to the sink. Since delay constraints are met at each level, all the sensor Nodes will be connected to the sink via feasible paths fulfilling delay constraints. In addition, the elaborated analysis of the time complexity and the approximation ratio of the SCA algorithm is given out. Extensive simulations show that SCA can significantly save deployed Relay Nodes in comparison to existing algorithms.
-
a connectivity aware approximation algorithm for Relay Node placement in wireless sensor networks
IEEE Sensors Journal, 2016Co-Authors: Wei Liang, Meng Zheng, Hamid SharifAbstract:In two-tiered wireless sensor networks (WSNs), Relay Node placement is one of the key factors impacting the network energy consumption and the system overhead. In this paper, a novel connectivity-aware approximation algorithm for Relay Node placement in the WSNs is proposed to offer a major step forward in saving system overhead. In particular, a unique local search approximation algorithm (LSAA) is introduced to solve the Relay Node single cover (RNSC) problem. In this proposed LSAA approach, the sensor Nodes are allocated into groups and then a local set cover (SC) for each group is achieved by a local search algorithm. The union set of all the local SCs constitutes a SC of the RNSC problem. The approximation ratio and the time complexity of the LSAA are analyzed by rigorous proof. In addition, the LSAA approach has been extended to solve the Relay Node double cover problem. Then, a Relay location selection algorithm (RLSA) is proposed to utilize the resulting SC from the LSAA in combining RLSA with the minimum spanning tree heuristic to build the high-tier connectivity. As the RLSA searches for a nearest location to the sink Node for each Relay Node, the high-tier network built by the RLSA becomes denser than that by existing works. As a result, the number of added Relay Nodes for building the connectivity of the high-tier WSN can be significantly saved. Simulation results clearly demonstrate that the proposed LSAA outperforms the approaches reported in literature and the RLSA-based algorithm can noticeably save Relay Nodes newly deployed for the high-tier connectivity.
Chienchung Shen - One of the best experts on this subject based on the ideXlab platform.
-
fault tolerant Relay Node placement in heterogeneous wireless sensor networks
IEEE Transactions on Mobile Computing, 2010Co-Authors: Xiaofeng Han, Errol L Lloyd, Xiang Cao, Chienchung ShenAbstract:Existing work on placing additional Relay Nodes in wireless sensor networks to improve network connectivity typically assumes homogeneous wireless sensor Nodes with an identical transmission radius. In contrast, this paper addresses the problem of deploying Relay Nodes to provide fault tolerance with higher network connectivity in heterogeneous wireless sensor networks, where sensor Nodes possess different transmission radii. Depending on the level of desired fault tolerance, such problems can be categorized as: 1) full fault-tolerant Relay Node placement, which aims to deploy a minimum number of Relay Nodes to establish k(k ? 1) vertexdisjoint paths between every pair of sensor and/or Relay Nodes and 2) partial fault-tolerant Relay Node placement, which aims to deploy a minimum number of Relay Nodes to establish k(k ? 1) vertex-disjoint paths only between every pair of sensor Nodes. Due to the different transmission radii of sensor Nodes, these problems are further complicated by the existence of two different kinds of communication paths in heterogeneous wireless sensor networks, namely, two-way paths, along which wireless communications exist in both directions; and one-way paths, along which wireless communications exist in only one direction. Assuming that sensor Nodes have different transmission radii, while Relay Nodes use the same transmission radius, this paper comprehensively analyzes the range of problems introduced by the different levels of fault tolerance (full or partial) coupled with the different types of path (one-way or two-way). Since each of these problems is NP-hard, we develop O(?k2)-approximation algorithms for both one-way and two-way partial fault-tolerant Relay Node placement, as well as O(?k3)-approximation algorithms for both one-way and two-way full fault-tolerant Relay Node placement (? is the best performance ratio of existing approximation algorithms for finding a minimum k-vertex connected spanning graph). To facilitate the applications in higher dimensions, we also extend these algorithms and derive their performance ratios in d-dimensional heterogeneous wireless sensor networks (d ? 3). Finally, heuristic implementations of these algorithms are evaluated via QualNet simulations.
-
fault tolerant Relay Node placement in heterogeneous wireless sensor networks
IEEE International Conference Computer and Communications, 2007Co-Authors: Xiaofeng Han, Errol L Lloyd, Xiang Cao, Chienchung ShenAbstract:Existing work on placing additional Relay Nodes in wireless sensor networks to improve network connectivity typically assumes homogeneous wireless sensor Nodes with an identical transmission radius. In contrast, this paper addresses the problem of deploying Relay Nodes to provide fault-tolerance with higher network connectivity in heterogeneous wireless sensor networks, where sensor Nodes possess different transmission radii. Depending on the level of desired fault-tolerance, such problems can be categorized as: (1) full fault-tolerance Relay Node placement, which aims to deploy a minimum number of Relay Nodes to establish k (k ges 1) vertex-disjoint paths between every pair of sensor and/or Relay Nodes; (2) partial fault-tolerance Relay Node placement, which aims to deploy a minimum number of Relay Nodes to establish k (k ges 1) vertex-disjoint paths only between every pair of sensor Nodes. Due to the different transmission radii of sensor Nodes, these problems are further complicated by the existence of two different kinds of communication paths in heterogeneous wireless sensor networks, namely two-way paths, along which wireless communications exist in both directions; and one-way paths, along which wireless communications exist in only one direction. Assuming that sensor Nodes have different transmission radii, while Relay Nodes use the same transmission radius, this paper comprehensively analyzes the range of problems introduced by the different levels of fault-tolerance (full or partial) coupled with the different types of path (one-way or two-way). Since each of these problems is NP-hard, we develop O(sigmak2)-approximation algorithms for both one-way and two-way partial fault-tolerance Relay Node placement, as well as O(sigmak3)-approximation algorithms for both one-way and two-way full fault-tolerance Relay Node placement (sigma is the best performance ratio of existing approximation algorithms for finding a minimum k-vertex connected spanning graph). To facilitate the applications in higher dimensions, we also extend these algorithms and derive their performance ratios in d-dimensional heterogeneous wireless sensor networks (d ges 3). Finally, heuristic implementations of these algorithms are evaluated via simulations.
Guoliang Xue - One of the best experts on this subject based on the ideXlab platform.
-
two tiered constrained Relay Node placement in wireless sensor networks computational complexity and efficient approximations
IEEE Transactions on Mobile Computing, 2012Co-Authors: Dejun Yang, Satyajayant Misra, Xi Fang, Guoliang Xue, Junshan ZhangAbstract:In wireless sensor networks, Relay Node placement has been proposed to improve energy efficiency. In this paper, we study two-tiered constrained Relay Node placement problems, where the Relay Nodes can be placed only at some prespecified candidate locations. To meet the connectivity requirement, we study the connected single-cover problem where each sensor Node is covered by a base station or a Relay Node (to which the sensor Node can transmit data), and the Relay Nodes form a connected network with the base stations. To meet the survivability requirement, we study the 2-connected double-cover problem where each sensor Node is covered by two base stations or Relay Nodes, and the Relay Nodes form a 2-connected network with the base stations. We study these problems under the assumption that R \ge 2r > 0, where R and r are the communication ranges of the Relay Nodes and the sensor Nodes, respectively. We investigate the corresponding computational complexities, and propose novel polynomial time approximation algorithms for these problems. Specifically, for the connected single-cover problem, our algorithms have {\cal O}(1)-approximation ratios. For the 2-connected double-cover problem, our algorithms have {\cal O}(1)-approximation ratios for practical settings and {\cal O}(\ln n)-approximation ratios for arbitrary settings. Experimental results show that the number of Relay Nodes used by our algorithms is no more than twice of that used in an optimal solution.
-
constrained Relay Node placement in wireless sensor networks formulation and approximations
IEEE ACM Transactions on Networking, 2010Co-Authors: Satyajayant Misra, Guoliang Xue, Seung Don Hong, Jian TangAbstract:One approach to prolong the lifetime of a wireless sensor network (WSN) is to deploy some Relay Nodes to communicate with the sensor Nodes, other Relay Nodes, and the base stations. The Relay Node placement problem for wireless sensor networks is concerned with placing a minimum number of Relay Nodes into a wireless sensor network to meet certain connectivity or survivability requirements. Previous studies have concentrated on the unconstrained version of the problem in the sense that Relay Nodes can be placed anywhere. In practice, there may be some physical constraints on the placement of Relay Nodes. To address this issue, we study constrained versions of the Relay Node placement problem, where Relay Nodes can only be placed at a set of candidate locations. In the connected Relay Node placement problem, we want to place a minimum number of Relay Nodes to ensure that each sensor Node is connected with a base station through a bidirectional path. In the survivable Relay Node placement problem, we want to place a minimum number of Relay Nodes to ensure that each sensor Node is connected with two base stations (or the only base station in case there is only one base station) through two Node-disjoint bidirectional paths. For each of the two problems, we discuss its computational complexity and present a framework of polynomial time O(1)-approximation algorithms with small approximation ratios. Extensive numerical results showthat our approximation algorithms can produce solutions very close to optimal solutions.
-
constrained Relay Node placement in wireless sensor networks to meet connectivity and survivability requirements
International Conference on Computer Communications, 2008Co-Authors: Satyajayant Misra, Guoliang Xue, Seung Don Hong, Jian TangAbstract:The Relay Node placement problem for wireless sensor networks is concerned with placing a minimum number of Relay Nodes into a wireless sensor network to meet certain connectivity and survivability requirements. In this paper, we study constrained versions of the Relay Node placement problem, where Relay Nodes can only be placed at a subset of candidate locations. In the connected Relay Node placement problem, we want to place a minimum number of Relay Nodes to ensure the connectivity of the sensor Nodes and the base stations. In the survivable Relay Node placement problem, we want to place a minimum number of Relay Nodes to ensure the biconnectivity of the sensor Nodes and the base stations. For each of the two problems, we discuss its computational complexity, and present a framework of polynomial time O(1) -approximation algorithms with small approximation ratios.
-
fault tolerant Relay Node placement in wireless sensor networks problems and algorithms
IEEE International Conference Computer and Communications, 2007Co-Authors: Weiyi Zhang, Guoliang Xue, Satyajayant MisraAbstract:Two fundamental functions of the sensor Nodes in a wireless sensor network are to sense its environment and to transmit sensed information to a basestation. One approach to prolong sensor network lifetime is to deploy some Relay Nodes whose main function is to communicate with the sensor Nodes, other Relay Nodes, and the basestations. It is desirable to deploy a minimum number of Relay Nodes to achieve certain connectivity requirement. In this paper, we study four related fault-tolerant Relay Node placement problems, each of which has been previously studied only in some restricted form. For each of them, we discuss its computational complexity and present a polynomial time O(1)-approximation algorithm with a small approximation ratio. When the problem reduces to a previously studied form, our algorithm either improves the previous best algorithm or reduces to the previous best algorithm.
-
Relay Node placement in wireless sensor networks
IEEE Transactions on Computers, 2007Co-Authors: Errol L Lloyd, Guoliang XueAbstract:A wireless sensor network consists of many low-cost, low-power sensor Nodes, which can perform sensing, simple computation, and transmission of sensed information. Long distance transmission by sensor Nodes is not energy efficient since energy consumption is a superlinear function of the transmission distance. One approach to prolonging network lifetime while preserving network connectivity is to deploy a small number of costly, but more powerful, Relay Nodes whose main task is communication with other sensor or Relay Nodes. In this paper, we assume that sensor Nodes have communication range r>0, while Relay Nodes have communication range Rgesr, and we study two versions of Relay Node placement problems. In the first version, we want to deploy the minimum number of Relay Nodes so that, between each pair of sensor Nodes, there is a connecting path consisting of Relay and/or sensor Nodes. In the second version, we want to deploy the minimum number of Relay Nodes so that, between each pair of sensor Nodes, there is a connecting path consisting solely of Relay Nodes. We present a polynomial time 7-approximation algorithm for the first problem and a polynomial time (5+epsi)-approximation algorithm for the second problem, where epsi>0 can be any given constant
Longxiang Luo - One of the best experts on this subject based on the ideXlab platform.
-
Relay Node placement in wireless sensor networks from theory to practice
IEEE Transactions on Mobile Computing, 2021Co-Authors: Wei Liang, Meng Zheng, Longxiang LuoAbstract:The increasingly wide utilization of Wireless Sensor Networks (WSNs) in industrial applications outstands the significance of the Delay Constrained Relay Node Placement (DCRNP) problem. The unreliable and unpredictable wireless links in WSNs may lead existing algorithms to fail in practice. Therefore, we first conduct extensive real-world deployments under the guidance of existing algorithms to evaluate their performance and to gain some insights for designing practical deployment algorithms. Based on the experiences learned from practical experiments, we first devise a Set-Covering-based Algorithm (SCA) which figures out the DCRNP problem while trying to make the quality of each link better than a given threshold. As our experiments also show that the fault-tolerant topology can significantly improve network reliability, we then design a $k$ -Set-Covering-based Algorithm ( $k$ SCA) to build fault-tolerant WSNs based on the methodology of SCA. Furthermore, the elaborate analysis proves that both SCA and $k$ SCA are polynomial-time algorithms, and their approximation ratios are $\text{O}(\ln n)$ and $\text{O}(\lg n)$ , respectively, where $n$ is the number of sensor Nodes. Finally, extensive experiments are performed under the guidance of SCA and $k$ SCA to demonstrate the effectivenesses of these two algorithms.
-
Relay Node placement in wireless sensor networks from theory to practice
IEEE Transactions on Mobile Computing, 2021Co-Authors: Wei Liang, Meng Zheng, Longxiang LuoAbstract:The increasingly wide utilization of Wireless Sensor Networks (WSNs) in industrial applications outstands the significance of the Delay Constrained Relay Node Placement (DCRNP) problem. Existing algorithms to the DCRNP problem are designed based on the ideal geometric disk wireless channel model, and no real-world deployments are performed to verify the effectiveness of these algorithms. However, the unreliable and unpredictable wireless links in WSNs may lead these algorithms to fail in practice. Therefore, we first conduct extensive real-world deployments under the guidance of existing algorithms to evaluate their performance and to gain some insights for designing practical deployment algorithms. The results exhibit that the WSNs built by existing algorithms have a favorable performance in end-to-end delay but a poor performance in reliability, which is mainly due to the lack of methods ensuring high-quality links. To this end, we first devise a Set-Covering-based Algorithm (SCA) which figures out the DCRNP problem while ensuring the quality of each link better than a given threshold. As our experiments also show that the fault-tolerant topology can significantly improve network reliability, we then design a $k$ k -Set-Covering-based Algorithm ( $k$ k SCA) to build fault-tolerant WSNs based on the methodology of SCA. Furthermore, the elaborate analysis proves that both SCA and $k$ k SCA are polynomial-time algorithms, and their approximation ratios are both O( $\ln n$ ln n ), where $n$ n is the number of sensor Nodes. Finally, extensive experiments are performed under the guidance of SCA and $k$ k SCA to demonstrate the effectiveness of these two algorithms.