For many emerging mobile broadband services and applications, the source and destination are located in the same local region. Consequently, it is very important to design access networks to facilitate efficient local...
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ISBN:
(纸本)9781467399531
For many emerging mobile broadband services and applications, the source and destination are located in the same local region. Consequently, it is very important to design access networks to facilitate efficient local data exchange. In the past few years, most existing studies focus on either the wired or wireless domains. In this paper, we aim to exploit both the wired and wireless domains. Specifically, we consider a Fiber-Wireless access network in which a passive optical network (PON) connects densely deployed base stations. In such a scenario, we propose a novel access scheme, namely, NCDA, where the main idea is to utilize both network coding and device association. To understand the potentials of NCDA, we first formulate a mixed integer nonlinear programming (MINLP) to minimize the weighted number of packet transmissions (WNT), which is related to both the system capacity and energy consumption. We then theoretically analyze the tight upper bounds of the minimal WNT in the PON, which helps us to approximate the original problem by a mixed integer linear programming (MILP). Next, we develop efficient algorithms based on linear programming relaxation to solve the optimal NCDA problem. To validate our design, we conduct extensive simulation experiments, which demonstrate the impact of important network parameters and the promising potentials of the proposed scheme.
network coding has been proven to be an effective technique to increase the throughput and enhance robustness of various wireless networks including tactical heterogeneous wireless networks. Usually, the tactical hete...
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ISBN:
(纸本)9781509028603
network coding has been proven to be an effective technique to increase the throughput and enhance robustness of various wireless networks including tactical heterogeneous wireless networks. Usually, the tactical heterogeneous wireless networks consist of different wireless links including high bandwidth links like IEEE 802.11 and low bandwidth links like UHF and VHF. Load balancing is an effective way to mitigate the network loading and improve overall performance of heterogeneous network. Traditional flow-based load balancing scheme performs poor and has a negative effect when applying network coding in tactical heterogeneous wireless networks. How to enhance the performance of network coding over tactical heterogeneous network is worthy of research. In this paper, with full consideration of different channel propagation characteristics and distinct transmission demands of different packets in a single stream, we propose a packet based load balancing scheme, making appropriate use of highly unbalanced links by transmitting different types of packets on different channels. By making full use of the propagation characteristics of low bandwidth channels, our scheme can significantly shorten the end to end delay of feedback packets and improve the transmission reliability of feedback packets. Compared with flow -based load balancing, our scheme can reduce 63.47% of the redundant transmissions on average and achieve 15.53% improvement of throughput.
Road Side Units (RSUs) installed alongside the road in Vehicular Ad Hoc networks (VANETs) act as buffer points and alleviate the frequent vehicle-to-vehicle connectivity problem. In VANETs, submitting multi-item query...
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ISBN:
(纸本)9781509024797
Road Side Units (RSUs) installed alongside the road in Vehicular Ad Hoc networks (VANETs) act as buffer points and alleviate the frequent vehicle-to-vehicle connectivity problem. In VANETs, submitting multi-item query is a common phenomenon, for instance, a query with required traffic information of multiple routes. Unlike the single item query, a multi-item query only be satisfied successfully if all the required data items are served within the stipulated deadline. In serving multi-item query, the system also needs to address the query starvation problem which causes due to the presence of less popular data items in the same query with the high popular data items. In this paper, for serving multi-item queries efficiently, we have proposed an approach which integrates network coding with on-demand broadcasting in multi-RSU VANETs. The traditional on-demand broadcast only disseminates a single data item in a broadcast tick which restricts the maximum channel bandwidth utilization. On the contrary, our proposed approach uses network coding through which multiple data items can be broadcast in a single broadcast. Again, our proposed network coding based approach learns the cache information of vehicles intrinsically which cuts the overhead of network coding, namely avoids uploading cache information of vehicles to the RSU server explicitly. In addition, the proposed approach is equally good to integrate both with the item-level and query-level on-demand scheduling algorithms for maximizing the system performance. Finally, we have performed an extensive simulation experiment to demonstrate the superiority of our proposed approach against the traditional broadcasting system for a number of on-demand scheduling algorithms.
In this work, we study the Yeung network coding entropic function outer bound and prove an equivalence relationship between its tightness and the edge removal problem. In addition, we derive an implicit characterizati...
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ISBN:
(纸本)9781509018062
In this work, we study the Yeung network coding entropic function outer bound and prove an equivalence relationship between its tightness and the edge removal problem. In addition, we derive an implicit characterization of the 0-error capacity region using restricted sets of entropic vectors.
network coding improves transmission efficiency by combining packets at relay nodes and thus reduces the number of packets sent to the network. It is a network layer solution to improve network throughput and transmis...
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ISBN:
(纸本)9781479966646
network coding improves transmission efficiency by combining packets at relay nodes and thus reduces the number of packets sent to the network. It is a network layer solution to improve network throughput and transmission efficiency. However, a coded packet must be decodable by the destination, otherwise it is a waste of resource to combine them together and to deliver the coded packet. This paper addresses how to find the coding solution that guarantees decodability at the destination. We first quantify the coding gain as the number of transmissions reduced, and then provide a method for runtime check whether a coding pair can be separated at the destination. The optimal coding solution is selected as the one that provides the maximum coding gain among all the decodable pairs. The algorithms can be applied to both unicast and multicast traffic. Simulation results show the number of transmissions can be reduced significantly, especially for multicast traffic where there are rich opportunities to apply network coding.
In this work we characterize the capacity region for multi-source multi-terminal acyclic network coding with dependent information sources. We show that a full characterization of the capacity region can be derived in...
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ISBN:
(纸本)9781509018062
In this work we characterize the capacity region for multi-source multi-terminal acyclic network coding with dependent information sources. We show that a full characterization of the capacity region can be derived in terms of entropy functions.
In traditional wireless networks, physical layer network coding (PNC) exploits the inverse additivity property of broadcast signals in the medium, an idea which is not directly applicable to molecular networks. In thi...
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ISBN:
(纸本)9781509019229
In traditional wireless networks, physical layer network coding (PNC) exploits the inverse additivity property of broadcast signals in the medium, an idea which is not directly applicable to molecular networks. In this paper, to make the natural XOR operation possible at the physical layer, we exploit the reaction of different molecule types and we propose a PNC scheme in diffusion-based molecular relay networks. For comparison, we consider the straightforward network coding (SNC) scheme in molecular networks. Assuming the ligand-receptor binding process at the receivers, we investigate the error performance of both schemes. It is observed that in addition to the simplicity of the proposed scheme, it improves the performance compared to the SNC scheme.
State of the art Random Linear network coding (RLNC) schemes assume that data streams generate packets with equal sizes. This is an assumption that results in the highest efficiency gains for RLNC. A typical solution ...
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ISBN:
(纸本)9781509019908
State of the art Random Linear network coding (RLNC) schemes assume that data streams generate packets with equal sizes. This is an assumption that results in the highest efficiency gains for RLNC. A typical solution for managing unequal packet sizes is to zero-pad the smallest packets. However, the efficiency of this strategy depends heavily on the packet size distribution and can significantly curb the gains of network coding in practice. The work by Compta et al. showed that this strategy could introduce an overhead as high as 100% for Internet traffic. Our work advocates for an alternative encoding and decoding designs, focused on processing macro-symbols (composed by a number of symbols in the appropriate finite field) instead of full zero-padded packets. Our proposed schemes provide on-the-fly decoding strategies to manage heterogeneous packet sizes without the need for fragmentation or bundling of packets, which are strategies that require additional signaling. Performance is evaluated using CAIDA TCP packets and 4k video traces. Our results show that our mechanisms reduce significantly the padding overhead even for small field sizes. Finally, our strategies provide a natural trade-off between computational complexity and overhead due to the low density of the code when decoded at a macro-symbol level.
Needs of content mass distribution in wireless networks are rapidly increasing. Due to wireless capacity limitation, CCN is considered as a promising future Internet technology because of its natural multicast enabled...
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ISBN:
(纸本)9781467383646
Needs of content mass distribution in wireless networks are rapidly increasing. Due to wireless capacity limitation, CCN is considered as a promising future Internet technology because of its natural multicast enabled architecture. To overcome multicast limitations, MNC based multicast schemes are also considered as optimal approaches. We propose an enhanced system architecture combining CCN and MNC for reliable wireless multicast, and present experimental results demonstrating its effectiveness.
network coding (NC) is an efficient way to decline the retransmission and provides a reliable connection in the wireless multicast network. However, in the NC schemes based on XOR, if one coded packet is lost, the tra...
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ISBN:
(纸本)9781467398039
network coding (NC) is an efficient way to decline the retransmission and provides a reliable connection in the wireless multicast network. However, in the NC schemes based on XOR, if one coded packet is lost, the transmitter must retransmit the same one until all the receivers correctly receive it. This strategy falls into the routine of ARQ (Automatic Repeat Request), which has already been proved with low bandwith efficiency. Accordingly, in this paper we proposed a dynamic linear combining retransmission(DLCR) strategy and fixed linear combining retransmission (FLCR) strategy based on the random network coding to improve the bandwidth efficiency in wireless multicast network. The key idea of the proposed schemes is to form the coded packet dynamically according to the real-time network status during the retransmission. Besides, we also analyzed the proposed schemes and get the corresponding theory analysis results. The simulations show that our schemes can well improve the efficiency of transmission.
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