In this paper, we analyze the performance of a peer-to-peer (P2P) distributed storage network based on the overlay architecture defined by the Wuala project. Although the original system is based on efficient erasure ...
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ISBN:
(纸本)9781424471898;9781424471904
In this paper, we analyze the performance of a peer-to-peer (P2P) distributed storage network based on the overlay architecture defined by the Wuala project. Although the original system is based on efficient erasure codes, e.g., Reed-Solomon codes, we investigate the use of a "simple" network coding strategy, which leverages on the well-known idea of randomized network coding. In particular, when a resource is published in the network, the fragments are randomly encoded with a predetermined overhead, which is consistent with the erasure coding strategy. Moreover, no regular network maintenance is scheduled to guarantee that a client node is able to successfully complete a resource download. We instead propose that a client node generates new fragments, to be stored in the network, when it is able to successfully download the entire resource. Our simulation results show that this simple coding strategy reduces the amount of data flowing in the network, thus obtaining more free disk space on storage nodes.
We introduce a technique for establishing and amplifying gaps between parameters of network coding and index coding problems. The technique uses linear programs to establish separations between combinatorial and codin...
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We introduce a technique for establishing and amplifying gaps between parameters of network coding and index coding problems. The technique uses linear programs to establish separations between combinatorial and coding-theoretic parameters and applies hyper graph lexicographic products to amplify these separations. This entails combining the dual solutions of the lexicographic multiplicands and proving that this is a valid dual solution of the product. Our result is general enough to apply to a large family of linear programs. This blend of linear programs and lexicographic products gives a recipe for constructing hard instances in which the gap between combinatorial or coding-theoretic parameters is polynomially large. We find polynomial gaps in cases in which the largest previously known gaps were only small constant factors or entirely unknown. Most notably, we show a polynomial separation between linear and non-linear network coding rates. This involves exploiting a connection between matroids and index coding to establish a previously unknown separation between linear and non-linear index coding rates. We also construct index coding problems with a polynomial gap between the broadcast rate and the trivial lower bound for which no gap was previously known.
In the secure network coding for multicasting, there is loss of information rate due to inclusion of random bits at the source node. We show a method to eliminate that loss of information rate by using multiple statis...
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In the secure network coding for multicasting, there is loss of information rate due to inclusion of random bits at the source node. We show a method to eliminate that loss of information rate by using multiple statistically independent messages to be kept secret from an eavesdropper. The proposed scheme is an adaptation of Yamamoto et al.'s secure multiplex coding [14] to the secure network coding [4], [5], [20].
This paper deals with the design of transmit scheme for the network with two source-destination pairs. A joint network coding (NC) and superposition coding (JNS) scheme is proposed to realize a cooperative transmissio...
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This paper deals with the design of transmit scheme for the network with two source-destination pairs. A joint network coding (NC) and superposition coding (JNS) scheme is proposed to realize a cooperative transmission between two pairs. The use of NC is able to improve spectral efficiency over classical decode and forward (DF) relaying strategy by relaxing the orthogonality constraint between different data streams and mitigating the resultant interference through precoding /beamforming. In contrast to using the channel state information (CSI) based beamforming scheme which can achieve near-optimal performance but involves huge computational complexity, we propose to design the beamforming vector using the form of superposition coding, such that CSI at the transmitters are not required and the involved computation is greatly reduced. The theoretical analysis and simulation results reveal that the proposed scheme shows throughput and BER performances close to the near-optimal CSIT based scheme, while having a much lower implementation complexity.
In vehicular ad hoc networks (VANETs), due to the limited radio propagation range of wireless devices, many safety applications require a multihop broadcast protocol to disseminate traffic warning information. However...
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In vehicular ad hoc networks (VANETs), due to the limited radio propagation range of wireless devices, many safety applications require a multihop broadcast protocol to disseminate traffic warning information. However, providing an efficient multihop forwarding of broadcast messages has been a challenging problem due to vehicle movement, limited wireless resources, and unstable signal strength. In this paper we propose a broadcast protocol that can provide a low message overhead and a high packet dissemination ratio. The proposed scheme uses a fuzzy logic algorithm to choose the next hop relay nodes and uses network coding to improve the packet dissemination ratio without increasing the message overhead. By using the fuzzy logic algorithm, the protocol can choose the best relay node by taking intervehicle distance, vehicle velocity, and link quality into account. network coding is used to improve the packet reception ratio by utilizing the broadcast nature of wireless channels. We show the effectiveness of the proposed scheme by using both theoretical analysis and computer simulations.
Considering the problem of how to efficiently transmit unknown quantum states in multi-unicast networks, we propose a nonlinear quantum network coding scheme with classical communication resource. On the conditions of...
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ISBN:
(纸本)9781467395274
Considering the problem of how to efficiently transmit unknown quantum states in multi-unicast networks, we propose a nonlinear quantum network coding scheme with classical communication resource. On the conditions of free classical communication between adjacent nodes in a network, as well as unlimited capacities of classical channels, perfect quantum network coding is available. By means of local phase deviation correction, we design the encoding procedure of nonlinear coding scheme. Moreover, we provide the upper bound on the total number of classical communication which is required to achieve quantum communication, as well as the analysis of scheme property.
We compare the reliability performance gain of Random Linear network coding (RLNC) with Automatic Repeat Request (ARQ) for a wireless relay network taking into account overhead and complexity of feedback mechanism as ...
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We compare the reliability performance gain of Random Linear network coding (RLNC) with Automatic Repeat Request (ARQ) for a wireless relay network taking into account overhead and complexity of feedback mechanism as well as overhead due to encoding vector embedded in packet header under RLNC. Our goal is not to propose a new ARQ or RLNC error control protocol, but rather to study the fundamental properties of ARQ and RLNC under condition of finite block sizes. We consider an Enhanced ARQ (ARQ-E) scheme that exploits sender side path diversity between the sender and the relays as well as a Single Path Routing (ARQ-SPR) scheme that uses a hop-by-hop ARQ protocol. The performance metric of interest is reliability gain, the expected number of channel uses per data bit received at the receiver. In the case of AWGN channels, we compare the reliability performance of these protocols with each other and observe the fact that RLNC provides limited performance gains.
In this work we compare scheduling and coding strategies for a source node serving multiple multicast flows in a network. The coding strategy we consider is a form of random coding proposed in [6] and involves coding ...
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In this work we compare scheduling and coding strategies for a source node serving multiple multicast flows in a network. The coding strategy we consider is a form of random coding proposed in [6] and involves coding across flows, as treated in [2]. We show that there are configurations for which the coding strategy outperforms any scheduling strategy that uses channel state information.
Considering a wireless relay network composed of a source, several relays and a destination, a linear block network coding (LBNC) scheme is proposed to combat the lossy nature of wireless channel. The relays not only ...
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Considering a wireless relay network composed of a source, several relays and a destination, a linear block network coding (LBNC) scheme is proposed to combat the lossy nature of wireless channel. The relays not only replicate the messages received but also perform network coding according to a linear block generator matrix. A special case of LBNC, parity-check network coding (PCNC) scheme is firstly theoretically analyzed and the explicit Average Outage Probability (AOP) and Block Outage Probability (BOP) are derived. For comparison, advanced relay cooperation (ARC), where relays only replicate and forward messages without coding them, is also presented and analyzed. Numerical results show that PCNC performs better than ARC when SNR is high and the s - r link is in good condition. For general LBNC scheme, it is very complicated to calculate the precise outage probability due to the difference of generator matrices, and we turn to simulation to evaluate the outage performance. The result shows that the performance of (M + C, M) LBNC can be estimated by ([M/C] + 1, [M/C]) and ([M/C] + 1, [M/C]) PCNC.
coding opportunity is crucial to the practical XOR coding scheme which can utilize these opportunities to improve the throughput of wireless networks. While the coding opportunity discovery scheme has been proposed fo...
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coding opportunity is crucial to the practical XOR coding scheme which can utilize these opportunities to improve the throughput of wireless networks. While the coding opportunity discovery scheme has been proposed for link-state routing protocols, there still lacks fundamental analysis on how to discover the coding opportunity effectively. In the paper we introduce the importance of coding opportunity discovery. Then in pursuit of generality we theoretically analyze the condition that all the coding opportunities can be discovered when relay node has a chance to transmit. This condition fits into not only link-state routing protocols but also distance-vector ones. In addition, we present how to implement the condition for Ad-hoc On-demand Distance Vector (AODV) routing protocol which is a representative distance-vector one. Our results can be particularly useful for coding-related routing protocol design and analysis.
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