An analytical approach to evaluate the performance of the 3G/ad hoc integrated network is presented. A channel model capturing both path loss and shadowing is applied to the analysis so as to characterize power fallof...An analytical approach to evaluate the performance of the 3G/ad hoc integrated network is presented. A channel model capturing both path loss and shadowing is applied to the analysis so as to characterize power falloff vs. distance. The 3G/ad hoc integrated network scenario model is introduced briefly. Based on this model, several performances of the 3G/ ad hoc integrated network in terms of outage probability, call dropping probability and new call blocking probability are evaluated. The corresponding performance formulae are deduced in accordance with the analytical models. Meanwhile, the formula of the 3G/ad hoc integrated network capacity is deduced on the basis of the formula of the outage probability. It is observed from extensive simulation and numerical analysis that the 3G/ad hoc integrated network remarkably outperforms the 3G network with regards to the network performance. This derived evaluation approach can be applied into planning and optimization of the 3G/ad hoc network.展开更多
In order to save the energy and reduce the latency of the end-to-end transmission in mobile ad hoc networks an adaptive and distance-driven power control ADPC scheme is proposed by means of distance research in random...In order to save the energy and reduce the latency of the end-to-end transmission in mobile ad hoc networks an adaptive and distance-driven power control ADPC scheme is proposed by means of distance research in random geometrics. Through mathematical proof the optimal number of relay nodes and the optimal location of each node for data transmission can be obtained when a distance is given.In the ADPC first the source node computes the optimal number and the sites of the relay nodes between the source and the destination nodes.Then it searches feasible relay nodes around the optimal virtual relay-sites and selects one link with the minimal total transmission energy consumption for data transmission.Simulation results show that the ADPC can reduce both the energy dissipation and the end-to-end latency of the transmission.展开更多
An improved internetworking approach is proposed to enhance the Internet connectivity which is deteriorated due to unidirectional links and blind rebroadcasting of gateway discovery packets for mobile ad hoc networks....An improved internetworking approach is proposed to enhance the Internet connectivity which is deteriorated due to unidirectional links and blind rebroadcasting of gateway discovery packets for mobile ad hoc networks. The hybrid gateway discovery scheme that combined the advantages of a proactive and reactive gateway discovery approach is used to achieve high connectivity while keeping overhead costs low. By exchanging ad hoc on-demand distance vector （AODV） hello packet which includes additional fields named symmetric neighbor list and asymmetric neighbor list, unidirectional links are removed from route computation and broadcast storm can also be relieved simultaneously. Performance results using ns-2 simulations, under varying numbers of unidirectional links and node speeds, show that this improved Internet connectivity approach can provide better performance than others.展开更多
MANET routing is critical and routing decision should be made sooner before the node leaves the network.Fast decisions always compensate network performance.In addition,most MANET routing protocols assume a friendly a...MANET routing is critical and routing decision should be made sooner before the node leaves the network.Fast decisions always compensate network performance.In addition,most MANET routing protocols assume a friendly and cooperative environment,and hence are vulnerable to various attacks.Trust and Reputation would serve as a major solution to these problems.Learning the network characteristics and choosing right routing decisions at right times would be a significant solution.In this work,we have done an extensive survey of fault tolerant protocols and ant colony algorithms applied to routing in MANETs.We propose a QoS constrained fault tolerant ant lookahead routing algorithm which attempts to identify valid route and look-ahead route pairs which might help in choosing the alternate path in case of valid route failure.The results prove that the proposed algorithm takes better routing decisions with 20-30 percent improvement compared with existing ant colony algorithms.展开更多
Mobile Ad hoc Networks(MANETs) play an important role in emergency communications where network needs to be constructed temporarily and quickly.Since the nodes move randomly,routing protocols must be highly effective ...Mobile Ad hoc Networks(MANETs) play an important role in emergency communications where network needs to be constructed temporarily and quickly.Since the nodes move randomly,routing protocols must be highly effective and reliable to guarantee successful packet delivery.Based on the data delivery structure,most of the existing multicast routing protocols can be classified into two folders:tree-based and mesh-based.We observe that tree-based ones have high forwarding efficiency and low consumptions of bandwidth,and they may have poor robustness because only one link exists between two nodes.As a treebased multicast routing protocol,MAODV(Multicast Ad hoc On-demand Vector) shows an excellent performance in lightweight ad hoc networks.As the load of network increases,QoS(Quality of Service) is degraded obviously.In this paper,we analyze the impact of network load on MAODV protocol,and propose an optimized protocol MAODV-BB(Multicast Ad hoc On-demand Vector with Backup Branches),which improves robustness of the MAODV protocol by combining advantages of the tree structure and the mesh structure.It not only can update shorter tree branches but also construct a multicast tree with backup branches.Mathematical analysis and simulation results both demonstrate that the MAODV-BB protocol improves the network performance over conventional MAODV in heavy load ad hoc networks.展开更多
The scalability of routing architectures for large networks is one of the biggest challenges that the Internet faces today.Greedy routing,in which each node is assigned a locator used as a distance metric,recently rec...The scalability of routing architectures for large networks is one of the biggest challenges that the Internet faces today.Greedy routing,in which each node is assigned a locator used as a distance metric,recently received increased attention from researchers and is considered as a potential solution for scalable routing.In this paper,LMD—a local minimum driven method is proposed to compute the topology-based locator.To eliminate the negative effect of the " quasi" greedy property—transfer routes longer than the shortest routes,a two-stage routing strategy is introduced,which combines the greedy routing with source routing.The greedy routing path discovered and compressed in the first stage is then used by the following source-routing stage.Through extensive evaluations,based on synthetic topologies as well as on a snapshot of the real Internet AS(autonomous system)topology,it is shown that LMD guarantees 100%delivery rate on large networks with low stretch.展开更多
基金The National Natural Science Foundation of China(No.60872004)the Research Fund of National Mobile Communications Research Laboratory of Southeast University(No.2010A08)the Fundamental Research Funds for the Central Universities(No.2009B21814)
文摘An analytical approach to evaluate the performance of the 3G/ad hoc integrated network is presented. A channel model capturing both path loss and shadowing is applied to the analysis so as to characterize power falloff vs. distance. The 3G/ad hoc integrated network scenario model is introduced briefly. Based on this model, several performances of the 3G/ ad hoc integrated network in terms of outage probability, call dropping probability and new call blocking probability are evaluated. The corresponding performance formulae are deduced in accordance with the analytical models. Meanwhile, the formula of the 3G/ad hoc integrated network capacity is deduced on the basis of the formula of the outage probability. It is observed from extensive simulation and numerical analysis that the 3G/ad hoc integrated network remarkably outperforms the 3G network with regards to the network performance. This derived evaluation approach can be applied into planning and optimization of the 3G/ad hoc network.
基金The National Basic Research Program of China(973 Program)(No.2009CB320501)the National Natural Science Foundation of China(No.61370209,61272532)the Natural Science Foundation of Jiangsu Province(No.BK2010414,BK2011335)
文摘In order to save the energy and reduce the latency of the end-to-end transmission in mobile ad hoc networks an adaptive and distance-driven power control ADPC scheme is proposed by means of distance research in random geometrics. Through mathematical proof the optimal number of relay nodes and the optimal location of each node for data transmission can be obtained when a distance is given.In the ADPC first the source node computes the optimal number and the sites of the relay nodes between the source and the destination nodes.Then it searches feasible relay nodes around the optimal virtual relay-sites and selects one link with the minimal total transmission energy consumption for data transmission.Simulation results show that the ADPC can reduce both the energy dissipation and the end-to-end latency of the transmission.
基金The National Natural Science Foundation of China(No60362001)
文摘An improved internetworking approach is proposed to enhance the Internet connectivity which is deteriorated due to unidirectional links and blind rebroadcasting of gateway discovery packets for mobile ad hoc networks. The hybrid gateway discovery scheme that combined the advantages of a proactive and reactive gateway discovery approach is used to achieve high connectivity while keeping overhead costs low. By exchanging ad hoc on-demand distance vector （AODV） hello packet which includes additional fields named symmetric neighbor list and asymmetric neighbor list, unidirectional links are removed from route computation and broadcast storm can also be relieved simultaneously. Performance results using ns-2 simulations, under varying numbers of unidirectional links and node speeds, show that this improved Internet connectivity approach can provide better performance than others.
文摘MANET routing is critical and routing decision should be made sooner before the node leaves the network.Fast decisions always compensate network performance.In addition,most MANET routing protocols assume a friendly and cooperative environment,and hence are vulnerable to various attacks.Trust and Reputation would serve as a major solution to these problems.Learning the network characteristics and choosing right routing decisions at right times would be a significant solution.In this work,we have done an extensive survey of fault tolerant protocols and ant colony algorithms applied to routing in MANETs.We propose a QoS constrained fault tolerant ant lookahead routing algorithm which attempts to identify valid route and look-ahead route pairs which might help in choosing the alternate path in case of valid route failure.The results prove that the proposed algorithm takes better routing decisions with 20-30 percent improvement compared with existing ant colony algorithms.
基金This work is supported by the NSFC （National Natural Science Foundation of China） No. 61371068 and No. 61172130, the National 863 program No.2011AA11A102-04-02 and Shenzhen Technology Research and Development Program No. CXZZ20120830100839333.
文摘Mobile Ad hoc Networks(MANETs) play an important role in emergency communications where network needs to be constructed temporarily and quickly.Since the nodes move randomly,routing protocols must be highly effective and reliable to guarantee successful packet delivery.Based on the data delivery structure,most of the existing multicast routing protocols can be classified into two folders:tree-based and mesh-based.We observe that tree-based ones have high forwarding efficiency and low consumptions of bandwidth,and they may have poor robustness because only one link exists between two nodes.As a treebased multicast routing protocol,MAODV(Multicast Ad hoc On-demand Vector) shows an excellent performance in lightweight ad hoc networks.As the load of network increases,QoS(Quality of Service) is degraded obviously.In this paper,we analyze the impact of network load on MAODV protocol,and propose an optimized protocol MAODV-BB(Multicast Ad hoc On-demand Vector with Backup Branches),which improves robustness of the MAODV protocol by combining advantages of the tree structure and the mesh structure.It not only can update shorter tree branches but also construct a multicast tree with backup branches.Mathematical analysis and simulation results both demonstrate that the MAODV-BB protocol improves the network performance over conventional MAODV in heavy load ad hoc networks.
基金Supported by the National High Technology Research and Development Program of China(No.2013AA013501)the National Program on Key Basic Research Project(No.2012CB315801)+1 种基金the National Natural Science Foundation of China(No.61133015)the Science and Technology on Information Transmission and Dissemination in Communication Networks Laboratory,CETC54
文摘The scalability of routing architectures for large networks is one of the biggest challenges that the Internet faces today.Greedy routing,in which each node is assigned a locator used as a distance metric,recently received increased attention from researchers and is considered as a potential solution for scalable routing.In this paper,LMD—a local minimum driven method is proposed to compute the topology-based locator.To eliminate the negative effect of the " quasi" greedy property—transfer routes longer than the shortest routes,a two-stage routing strategy is introduced,which combines the greedy routing with source routing.The greedy routing path discovered and compressed in the first stage is then used by the following source-routing stage.Through extensive evaluations,based on synthetic topologies as well as on a snapshot of the real Internet AS(autonomous system)topology,it is shown that LMD guarantees 100%delivery rate on large networks with low stretch.
