Device-to-device (D2D) communications has been realized as an effective means to improve network throughput, reduce transmission latency, and extend cellular coverage in 5G systems. network coding is a well establishe...
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Device-to-device (D2D) communications has been realized as an effective means to improve network throughput, reduce transmission latency, and extend cellular coverage in 5G systems. network coding is a well established technique known for its capability to reduce the number of retransmissions. In this article, we review state-of-the-art network coding in relay-based D2D communications, in terms of application scenarios and network coding techniques. We then apply two representative network coding techniques to dual-hop D2D communications and present an efficient relay node selecting mechanism as a case study. We also outline potential future research directions, according to the current research challenges. Our intention is to provide researchers and practitioners with a comprehensive overview of the current research status in this area and hope that this article may motivate more researchers to participate in developing network coding techniques for different relay-based D2D communications scenarios.
A major benefit of employing network coding (NC) in cooperative communications (CCs) is its ability to reduce time-slot overhead. Such approach is called network-coded CC (or NC-CC). Most of the existing works have ma...
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A major benefit of employing network coding (NC) in cooperative communications (CCs) is its ability to reduce time-slot overhead. Such approach is called network-coded CC (or NC-CC). Most of the existing works have mainly focused on exploiting this benefit without considering its potential adverse effect. In this paper, we show that NC may not always benefit CC. We substantiate this important finding with two important scenarios: employing analog network coding (ANC) in amplify-and-forward (AF) CC, and digital network coding (DNC) in decode-and-forward (DF) CC. For both scenarios, we introduce the important concept of network coding noise (NC noise). We analyze the origin of this noise via a careful study of signal aggregation at a relay node and signal extraction at a destination node. We derive a closed-form expression for NC noise at each destination node and show that the existence of NC noise could diminish the advantage of NC in CC. Our results shed new light on how to use NC in CC most effectively.
The exponential growth of the mobile devices market, not only smartphones but also tablets, laptops or wearables, poses a serious challenge for 5G communications. Random linear network coding is a promising solution f...
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The exponential growth of the mobile devices market, not only smartphones but also tablets, laptops or wearables, poses a serious challenge for 5G communications. Random linear network coding is a promising solution for present and future networks as it has been shown to provide increased throughput, security and robustness for the transmission of data through the network. Most of the analysis and the demonstrators have focused on the study of data packets with the same size (number of bytes). This constitutes a best-case scenario as coded packets will incur little overhead to handle such packets. However, packet lengths are quite heterogeneous in real networks, which can cause a high overhead or, alternatively, a high delay in the transmission of data packets. As we show, this can have a severe effect on a variety of applications. This paper proposes a series of mechanisms to manage heterogeneous packet lengths and analyses the induced overhead of those mechanisms using real packet length distributions provided by the Center for Applied Internet Data Analysis (CAIDA) and own measurements using video content. Our results show that an appropriate packetisation of the data packets can reduce the overhead from over 100per cent (zero-padding packets) to below 5per cent for CAIDA packet distributions and that the right choice of parameters can reduce the overhead to less than 10per cent in the case of video data. Copyright (c) 2014 John Wiley & Sons, Ltd.
Due to the broadcast nature of wireless networks they have been a natural platform for applying network coding (NC). Wireless networks can benefit significantly from NC due to their broadcast nature and the opportunit...
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Due to the broadcast nature of wireless networks they have been a natural platform for applying network coding (NC). Wireless networks can benefit significantly from NC due to their broadcast nature and the opportunity of enhancing bandwidth utilization. In this paper, we develop Multi-Generation Mixing (MGM), which is a generalized approach for generation based network coding. With traditional generation based NC sender packets are grouped in generations where encoding and decoding are performed on packets that belong to the same generation. In scenarios where losses cause insufficient reception of encoded packets, NC losses occur. NC losses are expensive;the minimum unit of loss is the loss of one generation. The proposed MGM framework allows the encoding among generations for the purpose of enhancing NC decodability. With MGM in scenarios where insufficient number of encodings received of a generation, it is still possible to recover the generation using data encoded in other generations. We develop MGM encoding and decoding approaches, and demonstrate the improvements in performance achieved by MGM. Further, a canonical analytical model for MGM network coding is developed, and, extensive simulations over random wireless networks experiencing random packet losses are presented.
Content Centric networking (CCN) is a new network architecture around content dissemination and retrieval. Its request-response and in-network caching mechanisms can significantly improve the network performance in re...
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Content Centric networking (CCN) is a new network architecture around content dissemination and retrieval. Its request-response and in-network caching mechanisms can significantly improve the network performance in reducing the transmission delay. However, the in-network caching may prevent the network coding technique from being applied into CCN because cached coded blocks may not be linearly independent to each other such that they cannot be used for responding the future requests. In this paper, we propose a novel request-specified network coding (RSNC) scheme for efficiently encoding and delivering chunks of content. In this scheme, a new Interest coding and forwarding strategy is proposed for specifying network coding requirements and getting linearly independent coded blocks simultaneously from multiple nodes. Our simulation results show that the proposed scheme achieves better performance than conventional CCN in terms of average download time, cache hit ratio, and transmission amount. (C) 2016 Elsevier Ltd. All rights reserved.
It is a great challenge to transmit data in vehicular networks, where the link among nodes is very shaky because of the rapid movement of vehicles. In this paper, we propose a network coding with Crowdsourcing-based T...
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It is a great challenge to transmit data in vehicular networks, where the link among nodes is very shaky because of the rapid movement of vehicles. In this paper, we propose a network coding with Crowdsourcing-based Trajectory Estimation (NC/CTE) method to transmit data in vehicular networks. Key points are designated beforehand in movement area. Every node estimates which of Key points the other nodes in the discovered area close to at the different times. The estimation is completed by every node in crowdsourcing method based on the pre-trajectory of GPS navigation. network coding, recoding and reverse forwarding are used for data transmission according to the result of trajectory estimation. Simulation results show that NC/CTE is able to cut down 1/2 overhead messages of TBNC when mobile nodes have shared their GPS trajectories. It improves the reliability and scalability of vehicular networks. (C) 2016 Elsevier Ltd. All rights reserved.
network coding is an emerging technique known to improve the network performance in many aspects. In Vehicular Ad-hoc networks (VANET), the bandwidth is considered to be one of the most important network resources. In...
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network coding is an emerging technique known to improve the network performance in many aspects. In Vehicular Ad-hoc networks (VANET), the bandwidth is considered to be one of the most important network resources. In this paper, we propose a network coding technique to improve the bandwidth utilization for non-safety applications in VANET. In a scenario where there are two sources broadcasting the data into the same area at the same time, the relay will use the network coding technique to decrease the number of rebroadcasting events and the consumption of the bandwidth, However, a fundamental problem for the relay when it receives a packet, is whether to wait for a coding opportunity and save the bandwidth or send the packet directly and reduce the delay. In order to address such tradeoff, we introduce two versions of our protocol, namely buffer size control scheme (BSCS) and time control scheme (TCS);by both versions we aim to control the delay that is experienced by the packet at each hop, while achieving better bandwidth utilization. Up to 38 % improvement in the bandwidth utilization has been recorded, and both schemes have shown a considerable amount of control on the imposed delay.
Link breakage is one of the critical problems that limit the performance of multicast routing in wireless networks. To ease the problem, we apply network coding to the routing operation. In our proposal, data packets ...
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Link breakage is one of the critical problems that limit the performance of multicast routing in wireless networks. To ease the problem, we apply network coding to the routing operation. In our proposal, data packets are encoded by a random coding scheme. By performing a re-encoding process, the coding scheme is able to keep conveying the data in the network even though link breakage occurs (without the need of waiting for retransmission). To route encoded packets in the network, a disjoint-path tree is used, which is the routing structure constructed by combining a number of multicast trees without the overlapping links among them. Simulation results show that our proposal can effectively ease the impact of link breakage, achieving better packet delivery ratio and higher multicast capacity under different scenarios.
In this paper, we study the problem of distributing a real-time video sequence to a group of partially connected cooperative wireless devices using instantly decodable network coding (IDNC). In such a scenario, the co...
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In this paper, we study the problem of distributing a real-time video sequence to a group of partially connected cooperative wireless devices using instantly decodable network coding (IDNC). In such a scenario, the coding conflicts occur to service multiple devices with an immediately decodable packet, and the transmission conflicts occur from simultaneous transmissions of multiple devices. To avoid these conflicts, we introduce a novel IDNC graph that represents all feasible coding and transmission conflict-free decisions in one unified framework. Moreover, a real-time video sequence has a hard deadline and unequal importance of video packets. Using these video characteristics and the new IDNC graph, we formulate the problem of minimizing the mean video distortion before the deadline as a finite horizon Markov decision process (MDP) problem. However, the backward induction algorithm that finds the optimal policy of the MDP formulation has high modeling and computational complexities. To reduce these complexities, we further design a two-stage maximal independent set selection algorithm, which can efficiently reduce the mean video distortion before the deadline. Simulation results over a real video sequence show that our proposed IDNC algorithms improve the received video quality compared with the existing IDNC algorithms.
The paper proposes a resource efficient solution for network coding (NC) based congestion control consisting in identification around the congested links of multiple butterfly or other low complexity NC-capable topolo...
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The paper proposes a resource efficient solution for network coding (NC) based congestion control consisting in identification around the congested links of multiple butterfly or other low complexity NC-capable topologies by using the Discrete Lagrange Multiplier optimization algorithm. The identification of the NC-capable topologies is based on the resource management capabilities foreseen for the network entities of the Future Internet. The congestion control issue is tackled by separate encoding of appropriately selected groups of data flows passing through the bottleneck link. By optimal selection of the data flows to be encoded, the additional network resources required by the NC operations can be minimized. The encoding is realized by using an XOR-based algorithm adapted for unequal bit rate data flows, and the experimental performances are reported here. Due to its efficient usage of the network resources and high degree of scalability, the congestion control solution proposed in this paper is suitable for large bit rate transmissions, like video streaming.
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