Compared to single-hop networks such as WiFi, multihop infrastructure wireless mesh networks (WMNs) can potentially embrace the broadcast benefits of a wireless medium in a more flexible manner. Rather than being poin...
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Compared to single-hop networks such as WiFi, multihop infrastructure wireless mesh networks (WMNs) can potentially embrace the broadcast benefits of a wireless medium in a more flexible manner. Rather than being point-to-point, links in the WMNs may originate from a single node and reach more than one other node. Nodes located farther than a one-hop distance and overhearing such transmissions may opportunistically help relay packets for previous hops. This phenomenon is called opportunistic overhearing/listening. With multiple radios, a node can also improve its capacity by transmitting over multiple radios simultaneously using orthogonal channels. Capitalizing on these potential advantages requires effective routing and efficient mapping of channels to radios (channel assignment (CA)). While efficient channel assignment can greatly reduce interference from nearby transmitters, effective routing can potentially relieve congestion on paths to the infrastructure. Routing, however, requires that only packets pertaining to a particular connection be routed on a predetermined route. Random network coding (RNC) breaks this constraint by allowing nodes to randomly mix packets overheard so far before forwarding. A relay node thus only needs to know how many packets, and not which packets, it should send. We mathematically formulate the joint problem of random network coding, channel assignment, and broadcast link scheduling, taking into account opportunistic overhearing, the interference constraints, the coding constraints, the number of orthogonal channels, the number of radios per node, and fairness among unicast connections. Based on this formulation, we develop a suboptimal, auction-based solution for overall network throughput optimization. Performance evaluation results show that our algorithm can effectively exploit multiple radios and channels and can cope with fairness issues arising from auctions. Our algorithm also shows promising gains over traditional routing
Catering to the public nature of Ad hoc network in open channel and data communication being easily eavesdropped,this paper proposed an antieavesdropping algorithm which is based on network *** algorithm is based on t...
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Catering to the public nature of Ad hoc network in open channel and data communication being easily eavesdropped,this paper proposed an antieavesdropping algorithm which is based on network *** algorithm is based on the RSA signature algorithm introducing the timestamp and homomorphic mechanism to detect tampering and replay attacks,as the basis for calculating safety,being used as one of measurement indicators in router by node safety to establish t pieces of routing *** generates encoding vectors by introducing the random number when the source node is encoded and the random number will be divided into n *** long as the sink node receives t pieces of fragments,we can restore the original encoding vector and decode *** the eavesdropper wiretaps are less than t,they can not get any meaningful *** is designed for increasing the number of linearly independent coded *** can improve the decoding efficiency by adopting generational grouping strategy while being *** and theoretical analysis shows that the anti-eavesdropping algorithm based on network coding improves network performance and security by coding gain.
This paper is a sequel of previous work, in which we have studied the problem of congestions on the typically overloaded downlink channels in UMTS (Universal Mobile Telecommunication System) networks. Our concept is b...
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ISBN:
(纸本)9781424415571
This paper is a sequel of previous work, in which we have studied the problem of congestions on the typically overloaded downlink channels in UMTS (Universal Mobile Telecommunication System) networks. Our concept is based on the uplink/downlink traffic imbalance in 3G wireless networks and is realized by organizing seamless cooperation between peer-to-peer and cellular networks using a unified radio interface for both systems. The primary goal is to improve the spectral efficiency of cellular networks by enabling direct mobile-to-mobile (m2m) communication on temporarily unused uplink channels for the distribution of a large popular content in a non-real time multicast manner. The aim of this work is to further improve the interaction between cellular and peer-to-peer networks by generalizing the traditional scheduling paradigm. A network coding technique is embedded as a solution to the scheduling problem in the distributed dynamic environment of wireless large-scale networks. We investigate the performance of the system in terms of dependability of information distribution among m2m users. Simulations demonstrate the enhanced performance of the Me distribution in terms of Me download time. Furthermore, the obtained results highlight that network coding based m2m data transfer allows distribution of popular files to a large number of users while placing minimal bandwidth requirements on the central server.
network coding is a communication paradigm that allows intermediate nodes to mix packets instead of simply relaying them. Motivated by applications in military tactical networks, this paper explores the use of the net...
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ISBN:
(纸本)9788393484850
network coding is a communication paradigm that allows intermediate nodes to mix packets instead of simply relaying them. Motivated by applications in military tactical networks, this paper explores the use of the network coding. It has been proved that network coding has many benefits in wireless communications such as optimal capacity achievement and packet loss recovery. In this paper, we present a generic architecture for network coding for broadcast in wireless networks called GardiNet. GardiNet is generic;its design is divided into building blocks in order to enable it to adapt to different application scenarios. In this paper, we start by describing GardiNet for wireless ad hoc networks and in particular for wireless sensor networks (WSNs). Then, we present experiment results of GardiNet in FIT IoT-LAB, a real testbed of WSNs. Results show that network coding performs well under real wireless conditions. In addition, we highlight the benefit of the Sliding Encoding Window scheme of GardiNet (SEW) to allow sensors to decode packets in real time.
Most existing studies on Delay/Disruption Tolerant networks (DTNs) consider pair-wise node encountering that assumes nodes only meet in pairs. In many mobile wireless networks, a group of nodes, instead of only a pair...
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ISBN:
(纸本)9781467385909
Most existing studies on Delay/Disruption Tolerant networks (DTNs) consider pair-wise node encountering that assumes nodes only meet in pairs. In many mobile wireless networks, a group of nodes, instead of only a pair of nodes, may meet each other. In this paper, we study how to effectively transmit a set of packets from a source to a destination in such group meeting scenarios. The optimization goal is to minimize the delay for the packets to reach the destination while limiting the energy consumption. We first assume that node encountering is known beforehand, and develop an algorithm to obtain the minimum delay. We then develop two practical network coding based schemes. Both schemes use a token technique to limit the total number of transmissions, and only incur signaling at the beginning of a group meeting. One scheme requires nodes in a group to exchange their encoding matrices with each other, while the other only requires exchanging rank information. Simulation results demonstrate that both schemes achieve delays close to the minimum delay for moderate number of tokens. They present different tradeoffs in the number of transmissions and the signaling overhead.
In this paper, we focus on the intra-cluster information exchange problem and propose some novel solutions. We only concern about how to exchange information inside cluster of sensor networks efficiently and do not co...
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ISBN:
(纸本)9781424402632
In this paper, we focus on the intra-cluster information exchange problem and propose some novel solutions. We only concern about how to exchange information inside cluster of sensor networks efficiently and do not consider cluster forming process and MAC layer scheme. Firstly, the intra-cluster information exchange problem is introduced. And secondly, the circular and random cluster models are presented, based on which some algorithms are proposed, such as routing, flooding, relaying and network coding. After theoretical analysis and packet-level simulation comparison, we find that network coding algorithm allows to realize significant energy and time savings.
network coding may improve network efficiency. However, it is not necessary to code every link to meet a given transmission rate. In this paper, we consider the NP-hard problem of minimizing the number of coding links...
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ISBN:
(纸本)9781424492688
network coding may improve network efficiency. However, it is not necessary to code every link to meet a given transmission rate. In this paper, we consider the NP-hard problem of minimizing the number of coding links of a network for a given target transmission rate. Chemical Reaction Optimization (CRO) is a general purpose metaheuristic, which have been demonstrated to be effective in many optimization problems. We adopt the CRO framework to develop an algorithm to solve this NP-hard problem. Simulation results show that CRO outperforms existing algorithms with two sets of test network topologies.
The broadcast nature of satellite networks such as DVB-RCS based systems provides a highly effective medium for content distribution, especially in the case of geographically scattered clients. Non-real-time services ...
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ISBN:
(纸本)9781424442447
The broadcast nature of satellite networks such as DVB-RCS based systems provides a highly effective medium for content distribution, especially in the case of geographically scattered clients. Non-real-time services typically rely on application level protocols that often use forward error correction (FEC) and carousel data cycling schemes in unidirectional links. The presence of a feedback channel in satellite networks is mostly unexploited in the context of reliable multicast services. We show that network coding protocols offer a native and transparent solution for reliable multicast over satellites. When employing a feedback channel, network coding can reach near real-time performance at an efficiency level close to known theoretical bounds for lossy satellite links.
network coding is a technique in cooperative networks by allowing intermediate nodes to mix messages from multiple sources. In this paper, we consider network coding application in wireless multiple access relay chann...
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ISBN:
(纸本)9781467358293;9781467358309
network coding is a technique in cooperative networks by allowing intermediate nodes to mix messages from multiple sources. In this paper, we consider network coding application in wireless multiple access relay channels with and without direct links. The relays are equipped with multiple antennas for both system models. We investigate several different network coding techniques applicable for each system model, including analog network coding (ANC), space-time analog network coding (STANC), physical-layer network coding (PLNC), space-time decode-and-forward (STDF), etc. We describe in details those different schemes in two system models with transmission time slots constraints, and compare the error rate performance. Interestingly, simulation studies show that those schemes with network coding have not better performance than the schemes with decode-and-forward (DF).
network coding for two-way relaying in a three-node network is considered. The achievable rate regions under both traditional four-slot multi-hopping (FSMH) and network coding (MAC-XOR) are characterized, showing a co...
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ISBN:
(纸本)9781424420742
network coding for two-way relaying in a three-node network is considered. The achievable rate regions under both traditional four-slot multi-hopping (FSMH) and network coding (MAC-XOR) are characterized, showing a combination between the two is needed for a larger region. This is accomplished by an opportunistic network coding scheduling which requires minimal information. Queuing analysis shows that for any pair of random Poisson arrivals with rates within the convex hull of FSMH and MAC-XOR regions is stabilizable. Next we consider how traffic pattern, described by the rate ratio between uplink and downlink, influences the sum rate. It is analyzed and compared with that of FSMH. It is shown that network coding achieves the maximum gain when traffic is symmetric, while it could be worse than FSMH when the traffic is very asymmetric. How multiple antennas influence the performance of network coding is also discussed. Finally, simulations based on Erceg fading model under a WiMAX setting are presented, which shows that the network coding gain (vs FSMH) improves further under MIMO.
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