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2015
This document presents a network coding approach that allows coding decisions to be based on the instantaneous conditions at the network nodes. It uses dynamic rates and coefficients to constantly adapt to local conditions and to allow for provider and application differentiation.
In lossy environment like wireless networks, random losses are treated by TCP as signals of congestion and TCP cuts down the sending rate, leading to the performance degradation. The practical network coding system TCP/NC can address this problem. TCP/NC masks the random losses by allowing the destination to acknowledge every degree of freedom even though original data is not decoded yet. Consequently, TCP smoothly reacts to random losses without reducing the performance. The sole problem from TCP/NC is that TCP/NC sends redundant traffic every pre-set interval which does not recover random losses in time. We suggest an end-to-end adaptive redundancy control based on re-designing the coding scheme from TCP/NC, called Dynamic Coding (DynCod). Our main idea is how the destination can inform to the source whether the latest data sent from the source is decodable or not and how many packet losses occur via acknowledgement packets. Particularly, we change the principle of the information delivered by TCP ACKs: the destination does not only acknowledge every degree of freedom, but also announces how many unseen packets (≥ 0) remain in the coding window. The source can be informed via TCP ACKs and adjust the number of redundant packets accordingly. We have compared the performances of DynCod and TCP/NC using NS-2. The simulation results show that DynCod outperforms the original TCP/NC in terms of throughput and packet delivery time.
Abstract We survey a representative subset of applications that use network coding techniques in different environments. We identified two major scenarios in which such applications are used: distributed information storage and retrieval, and content distribution. Moreover, we survey how the inherent properties of network coding can be applied to security and network monitoring, and study existing applications that use network coding in sensor networks. Last, we conclude with directions for future research.
At present, video delivery over the wired or wireless packet-switched networks has been motivating a series of researches into video encoding, quality of service (QoS), multimedia communication, and service models of networks. However, most of researchers lack a suitable video delivery simulation platform closer to the real video delivery system. Different from other existing simulation mechanisms, a simulation mechanism is proposed in this paper, based on an existing simulation tool, NS-2. With the proposed mechanism, the video encoder/decoder component, the application layer QoS control component, and the simulated network have been fully integrated. This guarantees that the simulation procedures outside the simulated network like video encoding/decoding, do not affect simulation results. Finally, experimental results consolidate the fact that this mechanism is useful for video researchers when they evaluate new encoding algorithms and transmission protocols of video delivery.
EURASIP Journal on Advances in Signal Processing, 2017
Future networks are expected to depart from traditional routing schemes in order to embrace network coding (NC)-based schemes. These have created a lot of interest both in academia and industry in recent years. Under the NC paradigm, symbols are transported through the network by combining several information streams originating from the same or different sources. This special issue contains thirteen papers, some dealing with design aspects of NC and related concepts (e.g., fountain codes) and some showcasing the application of NC to new services and technologies, such as data multi-view streaming of video or underwater sensor networks. One can find papers that show how NC turns data transmission more robust to packet losses, faster to decode, and more resilient to network changes, such as dynamic topologies and different user options, and how NC can improve the overall throughput. This issue also includes papers showing that NC principles can be used at different layers of the networks (including the physical layer) and how the same fundamental principles can lead to new distributed storage systems. Some of the papers in this issue have a theoretical nature, including code design, while others describe hardware testbeds and prototypes.
2008
Network coding promises to significantly impact the way communications networks are designed, operated, and understood. This book presents a unified and intuitive overview of the theory, applications, challenges, and future directions of this emerging field, and is a must-have resource for those working in wireline or wireless networking. • Uses an engineering approach - explains the ideas and practical techniques • Covers mathematical underpinnings, practical algorithms, code selection, security, and network management • Discusses key topics of inter-session (non-multicast) network coding, lossy networks, lossless networks, and subgraph-selection algorithms Starting with basic concepts, models, and theory, then covering a core subset of results with full proofs, Ho and Lun provide an authoritative introduction to network coding that supplies both the background to support research and the practical considerations for designing coded networks. This is an essential resource for gradu...
In recent years, network coding has become one of the most interesting fields and has attracted considerable attention from both industry and academia. The idea of network coding is based on the concept of allowing intermediate nodes to encode and combine incoming packets instead of only copy and forward them. This approach, by augmenting the multicast and broadcast efficiency of multi-hop wireless networks, increases the capacity of the network and improves its throughput and robustness. While a wide variety of papers described applications of network coding in different types of networks such as delay tolerant networks, peer to peer networks and wireless sensor networks, the detailed practical implementation of network coding has not been noted in most papers. Since applying network coding in real scenarios requires an acceptable understanding of mathematics and algebra, especially linear equations, reduced row echelon matrices, field and its operations, this paper provides a comprehensive guidance for the implementation of almost all required concepts in network coding. The paper explains the implementation details of network coding in real scenarios and describes the effect of the field size on network coding.
2007
Network coding is a new paradigm that is promising to change the way networking is done. In network coding intermediate nodes combine different packets to exploit more bandwidth and throughput. In addition, network coding reduces both delay and energy requirements.
MILCOM 2007 - IEEE Military Communications Conference, 2007
This paper investigates the interaction between network coding and link-layer transmission rate diversity in multihop wireless networks. By appropriately mixing data packets at intermediate nodes, network coding allows a single multicast flow to achieve higher throughput to a set of receivers. Broadcast applications can also exploit link-layer rate diversity, whereby individual nodes can transmit at faster rates at the expense of corresponding smaller coverage area. We first demonstrate how combining rate-diversity with network coding can provide a larger capacity for data dissemination of a single multicast flow, and how consideration of rate diversity is critical for maximizing system throughput. We also study the impact of both network coding and rate diversity on the dissemination latency for a class of quasi real-time applications, where the freshness of disseminated data is important. Our results provide evidence that network coding may lead to a latency-vs-throughput tradeoff in wireless environments, and that it is thus necessary to adapt the degree of network coding to ensure conformance to both throughput and latency objectives. There is an increasing interest in understanding the potential performance gains accruing from the use of network coding in multi-hop wireless environments. In particular, many military battlefield scenarios exhibit two characteristics that appear to motivate the use of network coding: a) the reliance on bandwidth-constrained, ad-hoc wireless links (e.g. using MANETs formed by vehicle-mounted radios in urban insurgencies) and b) the need to disseminate information (e.g., maps, mission commands) to multiple recipients. The initial results on the power of network coding NC, such as the original demonstration in [1] of how in-network mixing of packets by intermediate nodes helps to achieve a communication capacity that is not achievable solely through routing, were obtained for the case of a lossless, wireline network. More recently, several groups have investigated the potential performance gains realized by network coding for both
EURASIP Journal on Advances in Signal Processing, Special Issue on Network Coding, 2017
Future networks are expected to depart from traditional routing schemes in order to embrace network coding (NC)-based schemes. These have created a lot of interest both in academia and industry in recent years. Under the NC paradigm, symbols are transported through the network by combining several information streams originating from the same or different sources. This special issue contains thirteen papers, some dealing with design aspects of NC and related concepts (e.g., fountain codes) and some showcasing the application of NC to new services and technologies, such as data multi-view streaming of video or underwater sensor networks. One can find papers that show how NC turns data transmission more robust to packet losses, faster to decode, and more resilient to network changes, such as dynamic topologies and different user options, and how NC can improve the overall throughput. This issue also includes papers showing that NC principles can be used at different layers of the networks (including the physical layer) and how the same fundamental principles can lead to new distributed storage systems. Some of the papers in this issue have a theoretical nature, including code design, while others describe hardware testbeds and prototypes.
We consider the problem of optimizing the performance of a network coding router with two stochastic flows. We develop a queueing model which accounts for the fact that coding is not performed when packets are transmitted, but is done by a separate program or hardware which operates independently of the hardware that sends packets out over links. We formulate and solve a constrained optimization problem which provides the optimal time that the router should wait before sending the information that it has uncoded, so that the average response time of the system is minimized. The trade-offs between delay and bandwidth or energy associated with the choice of the waiting time are also investigated, and the results indicate that network coding offers significant performance gains in a moderate to heavily loaded system.
This document summarizes recommended terminology for Network Coding concepts and constructs. It provides a comprehensive set of terms in order to avoid ambiguities in future IRTF and IETF documents on Network Coding.
2016
Network Coding is a relatively new forwarding paradigm where intermediate nodes perform a store, code, and forward operation on incoming packets. Traditional forwarding approaches, which employed a store and forward operation, have not been able to approach the limit of the max-flow min-cut throughput wherein sources transmitting information over bottleneck links have to compete for access to these links. With Network Coding, multiple sources are now able to transmit packets over bottleneck links simultaneously, achieving the max-flow min-cut through-put and increasing network capacity. While the majority of the contemporary literature has fo-cused on the performance of Network Coding from a capacity perspective, the aim of this research has taken a new direction focusing on two Quality of Service metrics, e.g., Packet Delivery Ratio (PDR) and Latency, in conjunction with Network Coding protocols in Mobile Ad Hoc Networks (MANETs). Simulations are performed on static and mobile envi...
The paper proposes a congestion control protocol based on Network Coding (NC) operations for the butterfly topology. The proposed protocol defines XOR-based coding and decoding algorithms adapted to streams having different rates and characteristics, as well as a signalling protocol required for dynamic activation and deactivation of NC operations. Some general principles related to the integration of NC operations into data transmission protocols are also discussed. The congestion control protocol proposed was simulated in OMNeT++ and implemented in a real network to demonstrate its feasibility and to test the functioning of the proposed coding and signalling algorithm in different scenarios.
2010 Proceedings of 19th International Conference on Computer Communications and Networks, 2010
We propose a framework for optimizing the quality of service of multiple simultaneous flows in wireless access networks via network coding. Specifically, we consider the typical scenario in which multiple flows originate from multiple sources in the Internet and terminate at multiple users in a wireless network. In the current infrastructure, the wireless base station is responsible for relaying the packets from the Internet to the wireless users without any modification to the packet content. On the other hand, in the proposed approach, the wireless base station is allowed to perform network coding by appropriate linear mixing and channel coding of packets from different incoming flows before broadcasting a single flow of mixed or coded packets to all wireless users. Each user then uses an appropriate decoding method to recover its own packets from the set of coded packets that it receives. We show that in principle, for the given channel conditions and QoS requirements, appropriate mixing and channel coding of packets across different flows can lead to substantial quality improvement for both real-time and non-real time flows. On the other hand, blind mixing can be detrimental. We formulate this mixing problem as a combinatorial optimization problem, and propose a heuristic algorithm based on simulated-annealing method to approximate the optimal solution. Simulation results verify the performance improvement resulting from the proposed approach over the non-network coding and the state-of-the-art network coding approaches.
International Journal of Computers Communications & Control, 2019
Practical experience of using opportunistic network coding has already been gained in several real network deployments, indicating the influence of some of the fundamental characteristics of the network and the traffic load. However, these aspects have not been systematically investigated in the scope of the construction of efficient and robust large-scale network-coding-enabled wireless mesh networks. In this paper we focus on these aspects using an example of two opportunistic networkcoding procedures: the well-known COPE and the Bearing Opportunistic Network coding (BON). In addition, the design aspects for network-coding-enabled wireless mesh networks and applications are discussed. We have shown that opportunistic network coding can improve the performance of different networks and supported applications in terms of throughput, delay and jitter, although the benefits are not significant in all the cases. Thus, the use of opportunistic network coding should be considered upfront during the wireless network design phase in order to obtain the greatest benefits.
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