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24th International Teletraffic Congress (ITC)

作者： Gourdin, Eric Wang, Yuhui France T&#x00E9 l&#x00E9

ISBN: (纸本)9780983628347

network coding has been shown to be the solution that allows to reach the theoretical maximum throughput in a capacitated telecommunication network [1]. It has also been shown to be a very appealing and practical alternative to routing-based approaches to send traffic from sources (servers) to terminals (clients) for many different applications. However, the initial theoretical claim of throughput benefit remains relatively unclear, mainly because the multicast throughput maximization problem is difficult to solve (it is closely related to the fractional Steiner tree packing problem which is NP-hard). In this paper, we show that these optimization problems are still tractable even for instances with a significant size (up to 50 nodes and 300 edges). We also propose and solve the multicast maximum throughput problem with an additional constraint on the number of multicast trees. We apply our algorithms on large sets of randomly generated instances, mainly based on bidirected graphs, because they are the most relevant to model fixed telecommunication infrastructures. The main result of our intensive experimental study is that, in practice, network coding does not increase throughput compared to traditional multicast. Instances showing a throughput gain can only be generated somewhat artificially by imposing some structure or trying to maximize the throughput gap. However, when we limit the number of multicast trees, then, most of the times, very significant throughput gaps appeared. Since management constraints often impose on network administrators a very limited use of multicast trees, network coding appears clearly as a very nice alternative for delivering content to customers.

关键词： Throughput network coding Multicast Telecommunication networks redundant constraint Steiner trees Telecommunications

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Flexible and Dynamic network coding for Adaptive Data Transmission in DTNs

Flexible and Dynamic Network Coding for Adaptive Data Transm...

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8th IEEE International Wireless Communications and Mobile Computing Conference (IWCMC)

作者： Radenkovic, Milena Zakhary, Sameh Univ Nottingham Dept Comp Sci Nottingham NG8 1BB England

ISBN: (纸本)9781457713798

Existing network coding approaches for Delay-Tolerant networks (DTNs) do not detect and adapt to congestion in the network. In this paper we describe CafNC (Congestion aware forwarding with network coding) that combines adaptive network coding and adaptive forwarding in DTNs. In CafNC each node learns the status of its neighbours, and their ego-networks in order to detect coding opportunities, and codes as long as the recipients can decode. Our flexible design allows CafNC to efficiently support multiple unicast flows, with dynamic traffic demands and dynamic senders and receivers. We evaluate CafNC with two real connectivity traces and a realistic P2P application, introducing congestion by increasing the number of unicast flows in the network. Our results show that CafNC improves the success ratio, delay and packet loss, as the number of flows grows in comparison to no coding and hub-based static coding, while at the same time achieving efficient utilisation of network resources. We also show that static coding misses a number of coding opportunities and increases packet loss rates at times of increased congestion.

关键词： network coding DTN

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network synchronization scheme for scalable two-way multi-hop network employing MIMO network coding

Network synchronization scheme for scalable two-way multi-ho...

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IEEE 75th Vehicular Technology Conference (VTC Spring)

作者： Kida, Yutaro Mizutani, Keiichi Tran, Gia Khanh Miyamoto, Takehiro Sakaguchi, Kei Araki, Kiyomichi Tokyo Inst Technol Meguro Ku Ookayama 2-12-1 Tokyo 1528552 Japan Nihon Dengyo Kosaku Co Ltd Nissai Hanamizuki Sakado Saitama 3500269 Japan

ISBN: (纸本)9781467309905;9781467309882

In recent years, wireless mesh network functioning as backbone for various sensor network applications has been attracting much of attention. For realization of a high data rate and reliable mesh network, a synchronized mesh network technology employing OFDM has been proposed. However, the conventional scheme is not convenient as it requires network synchronization of all the nodes in the network performed before starting data communication. This paper proposes a novel scalable network synchronization scheme where data transmission and network synchronization setup can be done simultaneously. The proposed algorithm is implemented in developed 950 MHz TDD MIMO two-way relay network prototype hardware, and its behavior is verified.

关键词： Mesh networks wireless multi-hop networks network node data communication Scalability data transmission network coding network

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On Analysis of Wireless Uplink using Analog network coding with Non-Coherent Modulations

On Analysis of Wireless Uplink using Analog Network Coding w...

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IEEE Global Communications Conference (GLOBECOM)

作者： Guan, Wei Liu, K. J. Ray Univ Maryland Dept Elect & Comp Engn College Pk MD 20742 USA

ISBN: (纸本)9781467309219;9781467309202

Analog network coding (ANC) has been widely used in wireless uplink to improve throughput and provide spatial diversity. However, the receiver has to estimate the channel coefficients of all users to perform coherent detection, thus the signaling overhead is sometimes formidable and may even outweigh the performance gain. To reduce the channel estimation overhead, we study non-coherent modulations in this work with emphasis on receiver design and performance analysis. Depending on channel state information, we first develop the coherent, partial coherent and non-coherent receivers based on maximum likelihood (ML) principle. As the ML non-coherent receiver has a non-tractable integral form, we further propose two suboptimum receivers depending on the relative quality of source-relay channel and relay-destination channel. We also study the pairwise error probability, and show that full diversity is still achievable at high signal-to-noise ratios using non-coherent modulations;however, the error rate decreases much slower than that of coherent systems due to the incapability to efficiently suppress multi-user interferences. Extensive simulations are also given to verify our analytical results.

关键词： channel estimation diversity reception error statistics maximum likelihood detection modulation network coding radio receivers

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Infrastructure-Aid Information Forwarding Based on network coding in Vehicular Ad Hoc networks

Infrastructure-Aid Information Forwarding Based on Network C...

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Pacific-Asia Conference on Knowledge Engineering and Software Engineering

作者： Wang, Gang Xu, Yi Dai, Xia Beihang Univ Sch Elect & Informat Engn Beijing Peoples R China

ISBN: (纸本)9783642253485;9783642253492

In this paper, we present an analytical study for data dissemination in vehicular ad hoc networks (VANET) in the urban areas. Without any routing protocol, random linear network coding (RLNC) is an efficient method in practical scenarios contrasted with flooding. In such scenarios, some vehicles cannot communicate with others due to their mobility and non-connection with the neighbors. To tackle this problem, we propose a mechanism using the roadside infrastructure to assist transmission, which allows the majority of vehicles in a connected domain. Through this mechanism, the packets delivery ratio is improved significantly and other properties are minimally affected. Furthermore, the feasibility of this approach is verified through the simulations.

关键词： Infrastructure-aid information forwarding network coding vehicular ad hoc networks urban area

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Reducing Delays by network coding for Wireless Broadcasting in networks Using Relay Stations

Reducing Delays by Network Coding for Wireless Broadcasting ...

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IEEE 23rd International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

作者： Chen, Chao Baek, Seung Jun Korea Univ Dept Comp & Commun Seoul South Korea

ISBN: (纸本)9781467325691

We consider the problem of reducing delays in block transmissions of packets over multicast erasure channels in heterogeneous networks using relay stations. The macro base station performs random linear network coding over a block of packets which are relayed to the relay station which broadcasts the packets to the users. We propose a fluid approximation to our problem, and obtain the optimal solution for the fluid model when the users' channels are homogeneous. For the general case we propose an approximate algorithm which is simple to implement. We observe that it is crucial to explore the trade-off between the opportunity in the users' channels and moving packets out of the system. Simulation results show that our scheme achieves a decoding delay which is close to a theoretical lower bound.

关键词： Relay stations Packet network coding Consumers broadcasting Heterogeneous networks Lower bound optimal solution relay

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Optimal Dedicated Protection Approach to Shared Risk Link Group Failures using network coding

Optimal Dedicated Protection Approach to Shared Risk Link Gr...

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IEEE International Conference on Communications (ICC)

作者： Babarczi, Peter Tapolcai, Janos Ho, Pin-Han Medard, Muriel Budapest Univ Technol & Econ Dept Telecommun & Media Informat Budapest Hungary Univ Waterloo Dept Elect & Comp Engn Waterloo ON N2L 3G1 Canada MIT Elect Res Lab Cambridge MA 02139 USA

ISBN: (纸本)9781457720536

Survivable routing serves as a key role in connection-oriented communication networks for achieving desired service availability for each connection. This is particularly critical for the success of all-optical mesh networks where each lightpath carries a huge amount of data. Currently, 1 + 1 dedicated path protection appears to be the most widely deployed network resilience mechanism because it offers instantaneous recovery from network failures. However, 1 + 1 protection consumes almost twice as much capacity as required, which imposes a stringent constraint on network resource utilization. In addition, finding an SRLG-disjoint path is essential for 1 + 1 protection, which is nonetheless subject to non-trivial computation complexity and may fail in some SRLG scenarios. To address these problems, we introduce a novel framework of 1 + 1 protection, called Generalized Dedicated Protection (GDP), for achieving instantaneous recovery from any SRLG failure event. It is demonstrated, that finding a non-bifurcated optimal solution for GDP is NP-complete. Thus, the paper presents a novel scheme applying Generalized Dedicated Protection and network coding (GDP-NC) to ensure both optimal resource utilization among dedicated protection approaches and instantaneous recovery for single unicast flows, which can be split into multiple parts in all-optical networks. We demonstrate that the proposed GDP-NC survivable routing problem is polynomial-time solvable, owing to the ability to bifurcate flows. This flexibility comes at the expense of additional hardware for linear combination operations for the optical flows.

关键词： network coding

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Comments on Cut-Set Bounds on network Function Computation

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IEEE TRANSACTIONS ON INFORMATION THEORY 2018年第9期64卷 6454-6459页

作者： Huang, Cupjin Tan, Zihan Yang, Shenghao Guang, Xuan Univ Michigan Dept Elect Engn & Comp Sci Ann Arbor MI 48109 USA Univ Chicago Dept Comp Sci Chicago IL 60637 USA Chinese Univ Hong Kong Sch Sci & Engn Shenzhen 518172 Peoples R China Chinese Univ Hong Kong Shenzhen Key Lab IoT Intelligent Syst & Wireless Shenzhen 518172 Peoples R China Shenzhen Res Inst Big Data Shenzhen 518172 Peoples R China Nankai Univ Sch Math Sci Tianjin 300071 Peoples R China Nankai Univ LPMC Tianjin 300071 Peoples R China Chinese Univ Hong Kong Inst Network Coding Hong Kong Hong Kong Peoples R China

A function computation problem over a directed acyclic network has been considered in the literature, where a sink node is required to compute a target function correctly with the inputs arbitrarily generated at multiple source nodes. The network links are error free but capacity limited, and the intermediate nodes perform network coding. The computing rate of a network code is the average number of times that the target function is computed for one use of the network, i.e., each link in the network is used at most once. In the existing papers, two cut-set bounds were proposed on the computing rate. However, we in this paper show that these bounds are not valid for general network function computation problems. We analyze the reason of the invalidity and propose a general cut-set bound by using a new equivalence relation associated with the inputs of the target function. Moreover, some results in the existing papers were proved by applying the invalid upper bound. We also justify the validity of these results.

关键词： network function computation network coding computing capacity general cut-set bound tightness information theory

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Reliable network coding for Minimizing Decoding Delay and Feedback Overhead in Wireless Broadcasting

Reliable Network Coding for Minimizing Decoding Delay and Fe...

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IEEE 23rd International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

作者： Wu, Fei Hua, Cunqing Shan, Hangguan Huang, Aiping Zhejiang Univ Inst Informat & Commun Engn Hangzhou 310027 Peoples R China Zhejiang Prov Key Lab Informat Network Technol Hangzhou 310027 Peoples R China Shanghai Jiao Tong Univ Sch Informat Secur Engn Shanghai 200240 Peoples R China

ISBN: (纸本)9781467325691

network coding techniques have absorbed much attention for providing reliable broadcasting services in wireless networks. However, the intrinsic tradeoff among throughput, decoding delay, and feedback overhead has obstructed the application of the previously proposed schemes in practice. In this paper, we firstly propose a rate-controlled network coding scheme (RANC), which can effectively reduce the decoding delay of the receiver suffering from a poor channel condition, without compromising the system throughput. Based on RANC, we further propose a moving window network coding scheme together with an early loss alarm mechanism (MWNC-ELA), which achieves similar decoding delay performance to RANC, but greatly simplifies its feedback mechanism. As a benchmark of MWNC-ELA, we analyze the decoding delay performance of RANC using the random walk theory. Simulation results show that the proposed schemes outperform the existing solutions in terms of throughput, decoding delay, and feedback overhead.

关键词： Receivers Decoding Delay Throughput network coding Encoding Reliability

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On delay and security in network coding

On delay and security in network coding

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作者： Theodoros K. Dikaliotis California Institute of Technology

学位级别：博士

In this thesis, delay and security issues in network coding are considered. First, we study the delay incurred in the transmission of a fixed number of packets through acyclic networks comprised of erasure links. The two transmission schemes studied are routing with hop-by-hop retransmissions, where every node in the network simply stores and forwards its received packets, and linear coding, where nodes mix their packets by forwarding linear combinations of all their previously received packets. We show that even though the achievable rates of coding and routing are the same, network coding can have an increasingly better performance than routing as the number of packets increases. Secondly, we investigate the security benefits of network coding. We investigate the achievable secrecy rate region in a general network of noisy wiretap channels with general communication demands. The eavesdropper has access to an unknown set of links, and on the wiretapped links observes a degraded version of the intended receiver's observation. While characterizing the capacity in general is an open problem, in the noise-free case there exist inner and outer bounds. In the noisy case, we show how one can change any of the wiretap channels to a noiseless degraded broadcast channel, so that the derived network's rate region bounds, and under certain conditions is equivalent, to that of the initial network. Specifically, we showed that in case the eavesdropper can choose only a single link to wiretap at each time, then one can change all the links in the network with corresponding noiseless ones, creating an equivalent noiseless secrecy problem. In the case where the eavesdropper can wiretap multiple links simultaneously, we derive upper and lower bounding noiseless network problems. Finally, we consider design practical code design for the detection of adversarial errors in a distributed storage system. We build on work of functions that can fool linear polynomials to create and communi

关键词： information theory network coding secrecy

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