A recent approach COPE, presented by Katti etal. (Proc. ACM SIGCOMM 2006, pp. 243-254) for improving the throughput of unicast traffic in wireless multihop networks exploits the broadcast nature of the wireless medium...
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A recent approach COPE, presented by Katti etal. (Proc. ACM SIGCOMM 2006, pp. 243-254) for improving the throughput of unicast traffic in wireless multihop networks exploits the broadcast nature of the wireless medium through opportunistic networkcoding. In this paper, we analyze throughput improvements obtained by COPE-type networkcoding in wireless networks from a theoretical perspective. We make two key contributions. First, we obtain a theoretical formulation for computing the throughput of networkcoding on any wireless network topology and any pattern of concurrent unicast traffic sessions. Second, we advocate that routing be made aware of networkcoding opportunities rather than, as in COPE, being oblivious to it. More importantly, our model considers the tradeoff between routing flows close to each other for utilizing coding opportunities and away from each other for avoiding wireless interference. Our theoretical formulation provides a method for computing source destination routes and utilizing the best coding opportunities from available ones so as to maximize the throughput. We handle scheduling of broadcast transmissions subject to wireless transmit/receive diversity and link interference in our optimization framework. Using our formulations, we compare the performance of traditional unicast routing and networkcoding with coding-oblivious and coding-awarerouting on a variety of mesh network topologies, including some derived from contemporary mesh network testbeds. Our evaluations show that a route selection strategy that is aware of networkcoding opportunities leads to higher end-to-end throughput when compared to coding-oblivious routing strategies.
networkcoding, as one of the foremost techniques boosting the performance of the wireless networks, has recently acquired notable popularity. As a result, a new category of routing approaches named as the coding-awar...
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networkcoding, as one of the foremost techniques boosting the performance of the wireless networks, has recently acquired notable popularity. As a result, a new category of routing approaches named as the coding-awarerouting scheme, has been emerged. In such routing schemes, the possible coding opportunities are identified prior to the path establishment, and paths containing coding opportunities are prioritized to be established. Motivated by the appreciable efficiency of the coding-awarerouting schemes, this paper leverages fuzzy logic and proposes a novel coding-awarerouting approach alluded to as Fuzzy-logic-based network coding-aware routing (FNCR) protocol. Notwithstanding a number of previously proposed coding-awarerouting schemes which merely endeavor to establish paths including more coding opportunities, FNCR suggests embedding a purposefully designed fuzzy system in each node in order to calculate the overall desirability of the nodes in terms of some momentous factors such as the coding capability, the remaining energy, and the workload of the node. In addition to a new routing metric which utilizes the calculated overall desirability, the previously proposed coding conditions are modified such that more possible coding opportunities can now be identified. Simulation results demonstrate that FNCR outperforms the formerly proposed approaches employing networkcoding, in terms of throughput, end to end delay, packet delivery ratio, and lifetime of the network.
network coding-aware routing attempts to find coding opportunities between an incoming flow and existing flows in wireless ad hoc networks. However, we find that a problem of most proposed coding-awarerouting schemes...
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network coding-aware routing attempts to find coding opportunities between an incoming flow and existing flows in wireless ad hoc networks. However, we find that a problem of most proposed coding-awarerouting schemes is that they may misidentify the coding opportunities. Specifically, the opportunity misidentification may appear when a packet is about to be re-encoded. We call this the re-encoding problem. To solve this problem, we propose a principle called consistency of encoding and overhearing (CEO). By adhering to CEO, the encoding node is able to avoid misidentifying coding opportunities, thus ensuring the successful decoding of all encoded packets. In this letter, we first show the importance of CEO by analysis in a simple topology. Then, we introduce a distributed way to apply CEO to a coding-awarerouting scheme, and show the improved network performance with CEO by simulation in different scenarios.
networkcoding and opportunistic routing are two recognized innovative ideas to improve the performance of wireless networks by utilizing the broadcast nature of the wireless medium. In the last decade, there has been...
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networkcoding and opportunistic routing are two recognized innovative ideas to improve the performance of wireless networks by utilizing the broadcast nature of the wireless medium. In the last decade, there has been considerable research on how to synergize inter-flow networkcoding and opportunistic routing in a single joint protocol outperforming each in any scenario. This paper explains the motivation behind the integration of these two techniques, and highlights certain scenarios in which the joint approach may even degrade the performance, emphasizing the fact that their synergistic effect cannot be accomplished with a naive and perfunctory combination. This survey paper also provides a comprehensive taxonomy of the joint protocols in terms of their fundamental components and associated challenges, and compares existing joint protocols. We also present concluding remarks along with an outline of future research directions.
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