Communication security is a critical aspect of QoS provisioning in wireless mesh network (WMN). Because of the inherent characteristics of WMN, conventional security mechanisms cannot be applied. In order to guarant...Communication security is a critical aspect of QoS provisioning in wireless mesh network (WMN). Because of the inherent characteristics of WMN, conventional security mechanisms cannot be applied. In order to guarantee the communication security, a novel communication security mechanism is proposed. The mechanism uses a communication encryption scheme to encrypt data packets and employs a risk avoidance scheme to avoid the malicious nodes during communications. Simulation results indicate that the mechanism is able to provide secure communication effectively and reduce the damage of attacks through multiple paths.展开更多
Intrusion is any unwanted activity that can disrupt the normal functions of wired or wireless networks. Wireless mesh networking technology has been pivotal in providing an affordable means to deploy a network and all...Intrusion is any unwanted activity that can disrupt the normal functions of wired or wireless networks. Wireless mesh networking technology has been pivotal in providing an affordable means to deploy a network and allow omnipresent access to users on the Internet. A multitude of emerging public services rely on the widespread, high-speed, and inexpensive connectivity provided by such networks. The absence of a centralized network infrastructure and open shared medium makes WMNs particularly susceptible to malevolent attacks, especially in multihop networks. Hence, it is becoming increasingly important to ensure privacy, security, and resilience when designing such networks. An effective method to detect possible internal and external attack vectors is to use an intrusion detection system. Although many Intrusion Detection Systems (IDSs) were proposed for Wireless Mesh Networks (WMNs), they can only detect intrusions in a particular layer. Because WMNs are vulnerable to multilayer security attacks, a cross-layer IDS are required to detect and respond to such attacks. In this study, we analyzed cross-layer IDS options in WMN environments. The main objective was to understand how such schemes detect security attacks at several OSI layers. The suggested IDS is verified in many scenarios, and the experimental results show its efficiency.展开更多
Cognitive Wireless Mesh Networks(CWMN) is a novel wireless network which combines the advantage of Cognitive Radio(CR) and wireless mesh networks.CWMN can realize seamless in-tegration of heterogeneous wireless networ...Cognitive Wireless Mesh Networks(CWMN) is a novel wireless network which combines the advantage of Cognitive Radio(CR) and wireless mesh networks.CWMN can realize seamless in-tegration of heterogeneous wireless networks and achieve better radio resource utilization.However,it is particularly vulnerable due to its features of open medium,dynamic spectrum,dynamic topology,and multi-top routing,etc..Being a dynamic positive security strategy,intrusion detection can provide powerful safeguard to CWMN.In this paper,we introduce trust mechanism into CWMN with intrusion detection and present a trust establishment model based on intrusion detection.Node trust degree and the trust degree of data transmission channels between nodes are defined and an algorithm of calcu-lating trust degree is given based on distributed detection of attack to networks.A channel assignment and routing scheme is proposed,in which selects the trusted nodes and allocates data channel with high trust degree for the transmission between neighbor nodes to establish a trusted route.Simulation re-sults indicate that the scheme can vary channel allocation and routing dynamically according to network security state so as to avoid suspect nodes and unsafe channels,and improve the packet safe delivery fraction effectively.展开更多
The Wireless Mesh Network (WMN) has become a focus in research of wireless broadband communications . In a switching technologies - based wireless Mesh network, the entire network is regarded as an IP subnet, so it ca...The Wireless Mesh Network (WMN) has become a focus in research of wireless broadband communications . In a switching technologies - based wireless Mesh network, the entire network is regarded as an IP subnet, so it cannot be applied in situations where large coverage is required . The use of cooperative relaying technologies can improve the transmission rate and reliability of wireless link; while the wireless Mesh network, once integrated with cooperative relaying technologies and routing technologies , can improve its spectrum efficiency and cover a wide area . However, there are many problems to be solved with respect to standardization, key technologies research and industrialization. Therefore , the application of cooperative relaying technologies in wireless Mesh networks is still a great challenge .展开更多
The continuous increase of data transmission density in wireless mobile communications has posed a challenge to the system performance of Wireless Mesh Networks (WMNs ). There is a rule for wireless Ad hoc networks th...The continuous increase of data transmission density in wireless mobile communications has posed a challenge to the system performance of Wireless Mesh Networks (WMNs ). There is a rule for wireless Ad hoc networks that the average node capacity decreases while the number of nodes increases , so it is hard to establish a large - scale wireless Mesh network. Network scalability is very important for enhancing the adaptive networking capability of the wireless Mesh network. This article discusses key scalability technologies for Mesh Base Stations (BSs ) and Mesh Mobile Stations (MSs ), such as channel allocation, intelligent routing , multi- antenna , node classification, Quality of Service (QoS) differentiation and cooperative transmission.展开更多
Although the wireless broadband access system is developing rapidly, its development is limited due to some disadvantages , such as small capacity of bandwidth and small coverage . The Wireless Mesh Network (WMN) is o...Although the wireless broadband access system is developing rapidly, its development is limited due to some disadvantages , such as small capacity of bandwidth and small coverage . The Wireless Mesh Network (WMN) is one of the important technologies for 'last mile 'broadband wireless access . The WMN can integrate with multiple wireless systems , such as Wireless Local Area Network (WLAN), Wireless Personal Area Network (WPAN), and Wireless Metropolitan Area Network (WMAN), to improve the performance of the wireless network and enlarge the coverage range . With the wide applications of the WMN, the IEEE 802 standard group is devoted to promoting the development of the WMN technology and establishing the related technical standards . At present, WMN standards have appeared in IEEE 802.11s , 802.15, 802.16, and 802.20.展开更多
The convergence of heterogeneous wireless networks is a trend in the evolution of wireless networks.A new architecture for network convergence,named Wireless Cooperative Mesh Network,is proposed to solve such emerging...The convergence of heterogeneous wireless networks is a trend in the evolution of wireless networks.A new architecture for network convergence,named Wireless Cooperative Mesh Network,is proposed to solve such emerging problems in convergence as transmission mode selection,load balancing,routing and handover.The new architecture is based on the structure of Wireless Mesh Networks(WMNs),and cooperative communication is also employed to further optimize its structure and upgrade its performance.It can thus obtain advantages of both the Mesh technology(high spectrum efficiency and dynamic self-organization) and cooperative communication(high diversity gain and high energy efficiency).The new architecture serves as an efficient solution for wireless network convergence.展开更多
The Wireless Mesh Network (WMN) is a special kind of Ad hoc network with a hierarchical network structure . Its backbone transmission network has such characteristics as multi- hop , topology stability, no electricity...The Wireless Mesh Network (WMN) is a special kind of Ad hoc network with a hierarchical network structure . Its backbone transmission network has such characteristics as multi- hop , topology stability, no electricity supply constraints , convergence of flows . Improving the spatial reuse of spectrum is an effective approach to increase network capacity. The linchpin of this approach is to effectively control the interference range between wireless links . The multi- channel networking technology is one of the key technologies of WMN, and its core is the channel allocation through which the channel utilization can be maximized . The mutual interference between multi- hop wireless links should be considered when choosing the routing metrics in WMN. Through the load - balancing routing method , the network capacity and throughput of nodes can be improved .展开更多
A proactive routing protocol CL-OLSR (cross-layer based optimized link state routing) by using a brand-new routing metric CLM (cross-layer metric) is proposed. CL-OLSR takes into account four link quality impact f...A proactive routing protocol CL-OLSR (cross-layer based optimized link state routing) by using a brand-new routing metric CLM (cross-layer metric) is proposed. CL-OLSR takes into account four link quality impact factors in route calculation through the cross-layer operation mechanism: the node available bandwidth, the node load, the link delivery rate, and the link interference, and thus the effect of route selection is optimized greatly. The simulation results show that the proposed CL-OLSR protocol can not only improve the network throughput to a large extent, but also reduce the end-to-end delay, while achieving load balance route results.展开更多
In order to study the behavior and interconnection of network devices,graphs structures are used to formulate the properties in terms of mathematical models.Mesh network(meshnet)is a LAN topology in which devices are ...In order to study the behavior and interconnection of network devices,graphs structures are used to formulate the properties in terms of mathematical models.Mesh network(meshnet)is a LAN topology in which devices are connected either directly or through some intermediate devices.These terminating and intermediate devices are considered as vertices of graph whereas wired or wireless connections among these devices are shown as edges of graph.Topological indices are used to reflect structural property of graphs in form of one real number.This structural invariant has revolutionized the field of chemistry to identify molecular descriptors of chemical compounds.These indices are extensively used for establishing relationships between the structure of nanotubes and their physico-chemical properties.In this paper a representation of sodium chloride(NaCl)is studied,because structure of NaCl is same as the Cartesian product of three paths of length exactly like a mesh network.In this way the general formula obtained in this paper can be used in chemistry as well as for any degree-based topological polynomials of three-dimensional mesh networks.展开更多
In this paper, we propose an aware-based adaptive opportunistic retransmission control scheme for wireless multimedia Mesh networks. The proposed scheme provides maximum retransmis-sion count optimization based on env...In this paper, we propose an aware-based adaptive opportunistic retransmission control scheme for wireless multimedia Mesh networks. The proposed scheme provides maximum retransmis-sion count optimization based on environment-aware to improve packet relay probability. The scheme discriminates the types of packet loss in wireless link by means of environment information and selects the retransmission count by taking the IEEE 802.11 wireless channel characteristics into consideration. Furthermore, the maximum retransmission count of MAC is adjusted adaptively. Extensive simulations demonstrate that the proposed scheme significantly reduces packet collision probability and packet loss rate, and thus improves network throughput.展开更多
IEEE 802.11 based wireless mesh networks with directional antennas are expected to be a new promising technology and an economic approach for providing wireless broadband services in rural areas.In this paper,we discu...IEEE 802.11 based wireless mesh networks with directional antennas are expected to be a new promising technology and an economic approach for providing wireless broadband services in rural areas.In this paper,we discuss interference models and address how they can affect the design of channel assignment in rural mesh networks.We present a new channel assignment framework based on graph coloring for rural wireless mesh networks.The goal of the framework is to allow synchronously transmitting or receiving data from multiple neighbor links at the same time,and continuously doing full-duplex data transfer on every link,creating an efficient rural mesh network without interference.Channel assignment is shown to be NP-hard.We frame this channel allocation problem in terms of Adjacent Vertex Distinguishing Edge Coloring(AVDEC).Detailed assignment results on grid topology are presented and discussed.Furthermore,we design an algorithm.Finally,we evaluate the performance of the proposed algorithm through extensive simulations and show the algorithm is effective to the regular grid topologies,and the number of colors used by the algorithm is upper bounded by+1.Hence the algorithm guarantees that the number of channels available in standards such as IEEE802.11a is sufficient to have a valid AVDEC for many grid topologies.We also evaluate the proposed algorithm for arbitrary graphs.The algorithm provides a lower upper bound on the minimum number of channels to the AVDEC index channel assignment problem.展开更多
Wireless Mesh Network (WMN) is a new-type wireless network. Its core idea is that any of its wireless equipment can act as both an Access Point (AP) and a router. Each node in the network can send and receive signals ...Wireless Mesh Network (WMN) is a new-type wireless network. Its core idea is that any of its wireless equipment can act as both an Access Point (AP) and a router. Each node in the network can send and receive signals as well as directly communicate with one or several peer nodes. One important issue to be considered in wireless Mesh networks is how to secure reliable data transmission in multi-hop links. To solve the problem, the 3GPP system architecture proposes two functionalities: ARQ and HARQ. This paper presents two HARQ schemes, namely hop-by-hop and edge-to-edge, and three ARQ schemes: hop-by-hop, edge-to-edge, and last-hop. Moreover, it proposes three solutions for WMNs from the perspective of protocol stock design: layered cooperative mechanism, relay ARQ mechanism and multi-hop mechanism.展开更多
Wireless Mesh Network is a promising technology with many challenges yet to be addressed. Novel and efficient algorithms need to be developed for routing and admission control with the objective to increase the accept...Wireless Mesh Network is a promising technology with many challenges yet to be addressed. Novel and efficient algorithms need to be developed for routing and admission control with the objective to increase the acceptance ratio of new calls without affecting the Quality of Service (QoS) of the existing calls and to maintain the QoS level provided for the mobile calls. In this paper, a novel Markov Decision-based Admission Control and Routing (MDACR) algorithm is proposed. The MDACR algorithm finds a near optimal solution using the value iteration method. To increase the admission rate for both types of calls, a multi-homing admission and routing algorithm for handoff and new calls is proposed. This algorithm associates the user with two different access points which is beneficial in a highly congested network and proposes a new routing metric to assure seamless handoff in the network. Our proposed algorithm outperforms other algorithms in the literature in terms of handoff delay, blocking probability, and number of hard handoff.展开更多
Wireless Mesh Networks (WMNs) are vulnerable to various security threats because of their special infrastructure and communication mode, wherein insider attacks are the most challenging issue. To address this problem ...Wireless Mesh Networks (WMNs) are vulnerable to various security threats because of their special infrastructure and communication mode, wherein insider attacks are the most challenging issue. To address this problem and protect innocent users from malicious attacks, it is important to encourage cooperation and deter malicious behaviors. Reputation systems constitute a major category of techniques used for managing trust in distributed networks, and they are effective in characterizing and quantifying a node's behavior for WMNs. However, conventional layered reputation mechanisms ignore several key factors of reputation in other layers; therefore, they cannot provide optimal performance and accurate malicious node identification and isolation for WMNs. In this paper, we propose a novel dynamic reputation mechanism, SLCRM, which couples reputation systems with a cross-layer design and node-security-rating classification techniques to dynamically detect and restrict insider attacks. Simulation results show that in terms of network throughput, packet delivery ratio, malicious nodes identification, and success rates, SLCRM implements security protection against insider attacks in a more dynamic, effective, and efficient manner than the subjective logic and uncertainty-based reputation model and the familiarity-based reputation model.展开更多
In this paper, we propose a multi-source multi-path video streaming system for supporting high quality concurrent video-on-demand (VoD) services over wireless mesh networks (WMNs), and leverage forward error correctio...In this paper, we propose a multi-source multi-path video streaming system for supporting high quality concurrent video-on-demand (VoD) services over wireless mesh networks (WMNs), and leverage forward error correction to enhance the error resilience of the system. By taking wireless interference into consideration, we present a more realistic networking model to capture the characteristics of WMNs and then design a route selection scheme using a joint rate/interference-distortion optimiza- tion framework to help the system optimally select concurrent streaming paths. We mathematically formulate such a route selec- tion problem, and solve it heuristically using genetic algorithm. Simulation results demonstrate the effectiveness of our proposed scheme.展开更多
Wireless Mesh Network (WMN) is seen as an effective Internet access solution for dynamic wireless applications. For the low mobility of mesh routers in WMN, the backbone topography can be effectively maintained by pro...Wireless Mesh Network (WMN) is seen as an effective Internet access solution for dynamic wireless applications. For the low mobility of mesh routers in WMN, the backbone topography can be effectively maintained by proactive routing protocol. Pre-proposals like Tree Based Routing (TBR) protocol and Root Driven Routing (RDR) protocol are so centralized that they make the gateway become a bottleneck which severely restricts the network performance. We proposed an Optimized Tree-based Routing (OTR) protocol that logically separated the proactive tree into pieces. Route is partly computed by the branches instead of root. We also discussed the operation of multiple Internet gateways which is a main issue in WMN. The new proposal lightens the load in root, reduces the overhead and improves the throughput. Numerical analysis and simulation results confirm that the performance of WMN is improved and OTR is more suitable for large scale WMN.展开更多
This paper proposes a new Energyefficient Survivable Routing Protocol(ESRP)based on solar energy and wind mixed for power supply in green wireless mesh networks(WMNs).The ESRP combines hop penalty strategy and floodin...This paper proposes a new Energyefficient Survivable Routing Protocol(ESRP)based on solar energy and wind mixed for power supply in green wireless mesh networks(WMNs).The ESRP combines hop penalty strategy and flooding delaying strategy to improve the performances of traditional routing protocol.This paper uses QualNet to simulate and verify the performances of proposed ESRP.Compared with the traditional routing protocol,the simulation results show that the energy utilization of ESRP is more efficient by 13%.At the same time,ESRP is more load-balanced to postpone the appearance of the first energy depletion node and reduce the number of energy depletion nodes,and thus it effectively improves network survivability.展开更多
基金This project was supported by the National Natural Science Foundation of China (60573129).
文摘Communication security is a critical aspect of QoS provisioning in wireless mesh network (WMN). Because of the inherent characteristics of WMN, conventional security mechanisms cannot be applied. In order to guarantee the communication security, a novel communication security mechanism is proposed. The mechanism uses a communication encryption scheme to encrypt data packets and employs a risk avoidance scheme to avoid the malicious nodes during communications. Simulation results indicate that the mechanism is able to provide secure communication effectively and reduce the damage of attacks through multiple paths.
文摘Intrusion is any unwanted activity that can disrupt the normal functions of wired or wireless networks. Wireless mesh networking technology has been pivotal in providing an affordable means to deploy a network and allow omnipresent access to users on the Internet. A multitude of emerging public services rely on the widespread, high-speed, and inexpensive connectivity provided by such networks. The absence of a centralized network infrastructure and open shared medium makes WMNs particularly susceptible to malevolent attacks, especially in multihop networks. Hence, it is becoming increasingly important to ensure privacy, security, and resilience when designing such networks. An effective method to detect possible internal and external attack vectors is to use an intrusion detection system. Although many Intrusion Detection Systems (IDSs) were proposed for Wireless Mesh Networks (WMNs), they can only detect intrusions in a particular layer. Because WMNs are vulnerable to multilayer security attacks, a cross-layer IDS are required to detect and respond to such attacks. In this study, we analyzed cross-layer IDS options in WMN environments. The main objective was to understand how such schemes detect security attacks at several OSI layers. The suggested IDS is verified in many scenarios, and the experimental results show its efficiency.
基金Supported by the National High Technology Research and Development Program (No. 2009AA011504)
文摘Cognitive Wireless Mesh Networks(CWMN) is a novel wireless network which combines the advantage of Cognitive Radio(CR) and wireless mesh networks.CWMN can realize seamless in-tegration of heterogeneous wireless networks and achieve better radio resource utilization.However,it is particularly vulnerable due to its features of open medium,dynamic spectrum,dynamic topology,and multi-top routing,etc..Being a dynamic positive security strategy,intrusion detection can provide powerful safeguard to CWMN.In this paper,we introduce trust mechanism into CWMN with intrusion detection and present a trust establishment model based on intrusion detection.Node trust degree and the trust degree of data transmission channels between nodes are defined and an algorithm of calcu-lating trust degree is given based on distributed detection of attack to networks.A channel assignment and routing scheme is proposed,in which selects the trusted nodes and allocates data channel with high trust degree for the transmission between neighbor nodes to establish a trusted route.Simulation re-sults indicate that the scheme can vary channel allocation and routing dynamically according to network security state so as to avoid suspect nodes and unsafe channels,and improve the packet safe delivery fraction effectively.
文摘The Wireless Mesh Network (WMN) has become a focus in research of wireless broadband communications . In a switching technologies - based wireless Mesh network, the entire network is regarded as an IP subnet, so it cannot be applied in situations where large coverage is required . The use of cooperative relaying technologies can improve the transmission rate and reliability of wireless link; while the wireless Mesh network, once integrated with cooperative relaying technologies and routing technologies , can improve its spectrum efficiency and cover a wide area . However, there are many problems to be solved with respect to standardization, key technologies research and industrialization. Therefore , the application of cooperative relaying technologies in wireless Mesh networks is still a great challenge .
基金This work was funded by Special Standardization Foundation of the Science and Technology Commission of Shanghai Municipality under Grant 07DZ05018the Natural Science Foundation of Shanghai Municipality under Grant 07ZR14104
文摘The continuous increase of data transmission density in wireless mobile communications has posed a challenge to the system performance of Wireless Mesh Networks (WMNs ). There is a rule for wireless Ad hoc networks that the average node capacity decreases while the number of nodes increases , so it is hard to establish a large - scale wireless Mesh network. Network scalability is very important for enhancing the adaptive networking capability of the wireless Mesh network. This article discusses key scalability technologies for Mesh Base Stations (BSs ) and Mesh Mobile Stations (MSs ), such as channel allocation, intelligent routing , multi- antenna , node classification, Quality of Service (QoS) differentiation and cooperative transmission.
文摘Although the wireless broadband access system is developing rapidly, its development is limited due to some disadvantages , such as small capacity of bandwidth and small coverage . The Wireless Mesh Network (WMN) is one of the important technologies for 'last mile 'broadband wireless access . The WMN can integrate with multiple wireless systems , such as Wireless Local Area Network (WLAN), Wireless Personal Area Network (WPAN), and Wireless Metropolitan Area Network (WMAN), to improve the performance of the wireless network and enlarge the coverage range . With the wide applications of the WMN, the IEEE 802 standard group is devoted to promoting the development of the WMN technology and establishing the related technical standards . At present, WMN standards have appeared in IEEE 802.11s , 802.15, 802.16, and 802.20.
基金the National Natural Science Foundation of China under Grant No.60672079the Natural Science Foundation of Jiangsu Province under Grant No.BK2006701
文摘The convergence of heterogeneous wireless networks is a trend in the evolution of wireless networks.A new architecture for network convergence,named Wireless Cooperative Mesh Network,is proposed to solve such emerging problems in convergence as transmission mode selection,load balancing,routing and handover.The new architecture is based on the structure of Wireless Mesh Networks(WMNs),and cooperative communication is also employed to further optimize its structure and upgrade its performance.It can thus obtain advantages of both the Mesh technology(high spectrum efficiency and dynamic self-organization) and cooperative communication(high diversity gain and high energy efficiency).The new architecture serves as an efficient solution for wireless network convergence.
文摘The Wireless Mesh Network (WMN) is a special kind of Ad hoc network with a hierarchical network structure . Its backbone transmission network has such characteristics as multi- hop , topology stability, no electricity supply constraints , convergence of flows . Improving the spatial reuse of spectrum is an effective approach to increase network capacity. The linchpin of this approach is to effectively control the interference range between wireless links . The multi- channel networking technology is one of the key technologies of WMN, and its core is the channel allocation through which the channel utilization can be maximized . The mutual interference between multi- hop wireless links should be considered when choosing the routing metrics in WMN. Through the load - balancing routing method , the network capacity and throughput of nodes can be improved .
基金supported by the Fundamental Research Funds for the Central Universities under Grant No.ZYGX2009j006Foundation of Science & Technology Department of Sichuan Province under Grant No.2011GZ0192
文摘A proactive routing protocol CL-OLSR (cross-layer based optimized link state routing) by using a brand-new routing metric CLM (cross-layer metric) is proposed. CL-OLSR takes into account four link quality impact factors in route calculation through the cross-layer operation mechanism: the node available bandwidth, the node load, the link delivery rate, and the link interference, and thus the effect of route selection is optimized greatly. The simulation results show that the proposed CL-OLSR protocol can not only improve the network throughput to a large extent, but also reduce the end-to-end delay, while achieving load balance route results.
文摘In order to study the behavior and interconnection of network devices,graphs structures are used to formulate the properties in terms of mathematical models.Mesh network(meshnet)is a LAN topology in which devices are connected either directly or through some intermediate devices.These terminating and intermediate devices are considered as vertices of graph whereas wired or wireless connections among these devices are shown as edges of graph.Topological indices are used to reflect structural property of graphs in form of one real number.This structural invariant has revolutionized the field of chemistry to identify molecular descriptors of chemical compounds.These indices are extensively used for establishing relationships between the structure of nanotubes and their physico-chemical properties.In this paper a representation of sodium chloride(NaCl)is studied,because structure of NaCl is same as the Cartesian product of three paths of length exactly like a mesh network.In this way the general formula obtained in this paper can be used in chemistry as well as for any degree-based topological polynomials of three-dimensional mesh networks.
基金Supported by the National Natural Science Foundation of China (No. 60972038)the Jiangsu Province Universities Natural Science Research Key Grant Project (07KJA-51006)+1 种基金the Open Research Fund of National Mobile Communications Research Laboratory, Southeast University (N200911)Jiangsu Province Graduate In-novative Research Plan (CX09B_149Z)
文摘In this paper, we propose an aware-based adaptive opportunistic retransmission control scheme for wireless multimedia Mesh networks. The proposed scheme provides maximum retransmis-sion count optimization based on environment-aware to improve packet relay probability. The scheme discriminates the types of packet loss in wireless link by means of environment information and selects the retransmission count by taking the IEEE 802.11 wireless channel characteristics into consideration. Furthermore, the maximum retransmission count of MAC is adjusted adaptively. Extensive simulations demonstrate that the proposed scheme significantly reduces packet collision probability and packet loss rate, and thus improves network throughput.
基金Supported by the National Natural Science Foundation of China(No.71231004 and No.61004086)
文摘IEEE 802.11 based wireless mesh networks with directional antennas are expected to be a new promising technology and an economic approach for providing wireless broadband services in rural areas.In this paper,we discuss interference models and address how they can affect the design of channel assignment in rural mesh networks.We present a new channel assignment framework based on graph coloring for rural wireless mesh networks.The goal of the framework is to allow synchronously transmitting or receiving data from multiple neighbor links at the same time,and continuously doing full-duplex data transfer on every link,creating an efficient rural mesh network without interference.Channel assignment is shown to be NP-hard.We frame this channel allocation problem in terms of Adjacent Vertex Distinguishing Edge Coloring(AVDEC).Detailed assignment results on grid topology are presented and discussed.Furthermore,we design an algorithm.Finally,we evaluate the performance of the proposed algorithm through extensive simulations and show the algorithm is effective to the regular grid topologies,and the number of colors used by the algorithm is upper bounded by+1.Hence the algorithm guarantees that the number of channels available in standards such as IEEE802.11a is sufficient to have a valid AVDEC for many grid topologies.We also evaluate the proposed algorithm for arbitrary graphs.The algorithm provides a lower upper bound on the minimum number of channels to the AVDEC index channel assignment problem.
文摘Wireless Mesh Network (WMN) is a new-type wireless network. Its core idea is that any of its wireless equipment can act as both an Access Point (AP) and a router. Each node in the network can send and receive signals as well as directly communicate with one or several peer nodes. One important issue to be considered in wireless Mesh networks is how to secure reliable data transmission in multi-hop links. To solve the problem, the 3GPP system architecture proposes two functionalities: ARQ and HARQ. This paper presents two HARQ schemes, namely hop-by-hop and edge-to-edge, and three ARQ schemes: hop-by-hop, edge-to-edge, and last-hop. Moreover, it proposes three solutions for WMNs from the perspective of protocol stock design: layered cooperative mechanism, relay ARQ mechanism and multi-hop mechanism.
文摘Wireless Mesh Network is a promising technology with many challenges yet to be addressed. Novel and efficient algorithms need to be developed for routing and admission control with the objective to increase the acceptance ratio of new calls without affecting the Quality of Service (QoS) of the existing calls and to maintain the QoS level provided for the mobile calls. In this paper, a novel Markov Decision-based Admission Control and Routing (MDACR) algorithm is proposed. The MDACR algorithm finds a near optimal solution using the value iteration method. To increase the admission rate for both types of calls, a multi-homing admission and routing algorithm for handoff and new calls is proposed. This algorithm associates the user with two different access points which is beneficial in a highly congested network and proposes a new routing metric to assure seamless handoff in the network. Our proposed algorithm outperforms other algorithms in the literature in terms of handoff delay, blocking probability, and number of hard handoff.
基金supported by the Program for Changjiang Scholars and Innovative Research Team in University under Grant No.IRT1078the Key Program of NSFC-Guangdong Union Foundation under Grant No.U1135002+1 种基金Major National S&T Program under Grant No.2011ZX03005-002the Fundamental Research Funds for the Central Universities under Grant No.JY10000903001
文摘Wireless Mesh Networks (WMNs) are vulnerable to various security threats because of their special infrastructure and communication mode, wherein insider attacks are the most challenging issue. To address this problem and protect innocent users from malicious attacks, it is important to encourage cooperation and deter malicious behaviors. Reputation systems constitute a major category of techniques used for managing trust in distributed networks, and they are effective in characterizing and quantifying a node's behavior for WMNs. However, conventional layered reputation mechanisms ignore several key factors of reputation in other layers; therefore, they cannot provide optimal performance and accurate malicious node identification and isolation for WMNs. In this paper, we propose a novel dynamic reputation mechanism, SLCRM, which couples reputation systems with a cross-layer design and node-security-rating classification techniques to dynamically detect and restrict insider attacks. Simulation results show that in terms of network throughput, packet delivery ratio, malicious nodes identification, and success rates, SLCRM implements security protection against insider attacks in a more dynamic, effective, and efficient manner than the subjective logic and uncertainty-based reputation model and the familiarity-based reputation model.
基金Acknowledgements Project supported by the National Natural Science Foundation of China (Grant No.60932003), the National High Technology Development 863 Program of China (Grant No.2007AA01Z452, No. 2009AA01 Z118 ), Project supported by Shanghai Municipal Natural Science Foundation (Grant No.09ZRI414900), National Undergraduate Innovative Test Program (091024812).
文摘In this paper, we propose a multi-source multi-path video streaming system for supporting high quality concurrent video-on-demand (VoD) services over wireless mesh networks (WMNs), and leverage forward error correction to enhance the error resilience of the system. By taking wireless interference into consideration, we present a more realistic networking model to capture the characteristics of WMNs and then design a route selection scheme using a joint rate/interference-distortion optimiza- tion framework to help the system optimally select concurrent streaming paths. We mathematically formulate such a route selec- tion problem, and solve it heuristically using genetic algorithm. Simulation results demonstrate the effectiveness of our proposed scheme.
基金Acknowledgements This paper was supported by the Major National Science and Technology program under Grant No. 2011ZX03005-002 the National Natural Science Foundation of China under Grant No. 61100233 the Fundamental Universities under Grant No Research Funds for the Central K50510030010.
文摘Wireless Mesh Network (WMN) is seen as an effective Internet access solution for dynamic wireless applications. For the low mobility of mesh routers in WMN, the backbone topography can be effectively maintained by proactive routing protocol. Pre-proposals like Tree Based Routing (TBR) protocol and Root Driven Routing (RDR) protocol are so centralized that they make the gateway become a bottleneck which severely restricts the network performance. We proposed an Optimized Tree-based Routing (OTR) protocol that logically separated the proactive tree into pieces. Route is partly computed by the branches instead of root. We also discussed the operation of multiple Internet gateways which is a main issue in WMN. The new proposal lightens the load in root, reduces the overhead and improves the throughput. Numerical analysis and simulation results confirm that the performance of WMN is improved and OTR is more suitable for large scale WMN.
基金This work was supported in part by the National Natural Science Foundation of China (61172051, 61071124), the Fok Ying Tung Education Foundation (121065), the Program for New Century Excellent Talents in University (11-0075), the Fundamental Research Funds for the Central Universities (N110204001, N110604008), and the Specialized Research Fund for the Doctoral Program of Higher Education (20110042110023, 20110042120035).
文摘This paper proposes a new Energyefficient Survivable Routing Protocol(ESRP)based on solar energy and wind mixed for power supply in green wireless mesh networks(WMNs).The ESRP combines hop penalty strategy and flooding delaying strategy to improve the performances of traditional routing protocol.This paper uses QualNet to simulate and verify the performances of proposed ESRP.Compared with the traditional routing protocol,the simulation results show that the energy utilization of ESRP is more efficient by 13%.At the same time,ESRP is more load-balanced to postpone the appearance of the first energy depletion node and reduce the number of energy depletion nodes,and thus it effectively improves network survivability.