The problem of two sources wanting to share information through a potentially untrustworthy relay node is considered. The two sources transmit symbols simultaneously, and the relay node employs Physical-layer network ...
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The problem of two sources wanting to share information through a potentially untrustworthy relay node is considered. The two sources transmit symbols simultaneously, and the relay node employs Physical-layer network coding (PNC) to forward information back to the two sources in order to increase throughput. In such a system using PNC, the relay node can easily fool the source nodes by manipulating the PNC output symbols. To enable relay maliciousness detection, a class of variable-rate codes, called certification codes, is introduced. In a certification code, redundancy is added to the source message to act as a certificate, allowing a node to determine if the relay is behaving in a malicious manner. A simple binary certification code is designed and analyzed to demonstrate the proposed approach.
Error control is significant to network coding, since when unchecked, errors greatly deteriorate the throughput gains of network coding and seriously undermine both reliability and security of data. Two families of co...
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Error control is significant to network coding, since when unchecked, errors greatly deteriorate the throughput gains of network coding and seriously undermine both reliability and security of data. Two families of codes, subspace and rank metric codes, have been used to provide error control for random linear network coding. In this paper, we enhance the error correction capability of these two families of codes by using a novel two-tier decoding scheme. While the decoding of subspace and rank metric codes serves a second-tier decoding, we propose to perform a first-tier decoding on the packet level by taking advantage of Hamming distance properties of subspace and rank metric codes. This packet-level decoding can also be implemented by intermediate nodes to reduce error propagation. To support the first-tier decoding, we also investigate Hamming distance properties of three important families of subspace and rank metric codes, Gabidulin codes, Kotter-Kschischang codes, and Mahdavifar-Vardy codes. Both the two-tier decoding scheme and the Hamming distance properties of these codes are novel to the best of our knowledge.
A network-compressive transmission protocol is developed in which correlated sensor observations belonging to a finite alphabet are linearly combined as they traverse the network on their way to a sink node. Statistic...
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A network-compressive transmission protocol is developed in which correlated sensor observations belonging to a finite alphabet are linearly combined as they traverse the network on their way to a sink node. Statistical dependencies are modeled using factor graphs. The sum-product algorithm is run under different modeling assumptions to estimate the maximum a posteriori set of observations given the compressed measurements at the sink node. Error exponents are derived for cyclic and acyclic factor graphs using the method of types, showing that observations can be recovered with arbitrarily low probability of error as the network size grows. Simulated tests corroborate the theoretical claims.
The usage of random linear network coding in wireless sensor network is consistent with sociality, for this feature, proposed a network coding scheme for sociality for wireless sensor networks. Analyzed the process of...
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ISBN:
(纸本)9781467307215
The usage of random linear network coding in wireless sensor network is consistent with sociality, for this feature, proposed a network coding scheme for sociality for wireless sensor networks. Analyzed the process of coding and decoding of random linear network coding and summarized the advantages and disadvantages of the scheme in practical application, at last through NS2 to compare the scheme of using random linear network coding and traditional coding, the random linear network is better at network performance.
The performance of a joint Hierarchical Modulation (HM) and network coding (NC) scheme for two way relay networks is introduced and evaluated in this paper. The proposed scheme uses selective relaying based on a signa...
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The performance of a joint Hierarchical Modulation (HM) and network coding (NC) scheme for two way relay networks is introduced and evaluated in this paper. The proposed scheme uses selective relaying based on a signal-to-noise (SNR) threshold at the relay. In particular, a two way cooperative network with two sources and one relay is considered. Two different protection classes are modulated by a hierarchical 4/16-Quadrature Amplitude Modulation (QAM) constellation at the source. Based on the instantaneous received SNR at the relay, the relay decides to retransmit both classes by using a hierarchical 4/16-QAM constellation, the more- protection class by using a Quadrature Phase Shift Keying (QPSK) constellation, or remains silent. These thresholds at the relay give rise to multiple transmission scenarios in a two way cooperative network. Simulation results verify our analysis and efficacy of the scheme.
Short message noisy network coding (SNNC) transmits independent short messages in blocks rather than using long message repetitive encoding. SNNC is shown to achieve the same rates as noisy network coding (NNC) for di...
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ISBN:
(纸本)9781467325806
Short message noisy network coding (SNNC) transmits independent short messages in blocks rather than using long message repetitive encoding. SNNC is shown to achieve the same rates as noisy network coding (NNC) for discrete memoryless networks where each node transmits a multicast message. One advantage of SNNC is that backward decoding may be used which simplifies the analysis and understanding of the achievability proof. The analysis reveals that each decoder may ignore certain other nodes rather than including their message in the decoding procedure. Additionally, SNNC enables early decoding at nodes if the channel quality happens to be good.
A new spreading code based on a prime code for synchronous optical code-division multiple-access networks that can be used in monitoring applications has been proposed. The new code is referred to as "extended gr...
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A new spreading code based on a prime code for synchronous optical code-division multiple-access networks that can be used in monitoring applications has been proposed. The new code is referred to as "extended grouped new modified prime code." This new code has the ability to support more terminal devices than other prime codes. In addition, it patches subsequences with "0s" leading to lower power consumption. The proposed code has an improved cross-correlation resulting in enhanced BER performance. The code construction and parameters are provided. The operating performance, using incoherent on-off keying modulation and incoherent pulse position modulation systems, has been analyzed. The performance of the code was compared with other prime codes. The results demonstrate an improved performance, and a BER floor of 10(-9) was achieved.
network coding is a new technique which appeared in recent years. By employing the inherent broadcast nature of the wireless channel, it can achieve higher network throughput in wireless networks. Butterfly network mo...
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network coding is a new technique which appeared in recent years. By employing the inherent broadcast nature of the wireless channel, it can achieve higher network throughput in wireless networks. Butterfly network model depicts the basic component unit of wireless local area networks （WLANs）. In this paper, we propose an algorithm of MAC-based network coding specific to Butterfly networks - MBNC （MAC-Based network coding）. According to the differences of numbers of the buffered packets for upstream flows in the coding node’s FIFO output queue, it can increase coding opportunity as largely as possible by dynamically adjusting the contention windows of the MAC layers of upstream nodes, thus improves network performance. Performance analysis and simulation test proved that MBNC can greatly improve network throughput.
With the increasing popularity of online video streaming and broadcasting applications, video transmission has become the most bandwidth consumed application in the Internet. Unless resource utilisation is further opt...
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With the increasing popularity of online video streaming and broadcasting applications, video transmission has become the most bandwidth consumed application in the Internet. Unless resource utilisation is further optimised, existing networks would not be able to accommodate the forecasted demand for high volume video traffic. Random Linear network coding (RLNC) is a promising approach to increase the network throughput and robustness in order to facilitate high volume traffic. However, the performance gain obtained using RLNC decreases when the network packet loss rate increases. In response, this paper proposes to incorporate RLNC with a combined interleaving and a coding technique to improve the effectiveness of generating redundant packet combinations over classical RLNC to enhance the robustness against packet losses. Simulation results illustrate that the proposed method improves the probability of recovering lost data over the classical RLNC and the video transmission simulation results exhibit up to 5dB increase in PSNR and up to 14% increase in VQM utilising the same network resources at the same network conditions.
Recently, wireless communication methods that exploit the broadcast nature of the wireless medium have been attracting growing attention. Among these methods, opportunistic routing and network coding are regarded as t...
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Recently, wireless communication methods that exploit the broadcast nature of the wireless medium have been attracting growing attention. Among these methods, opportunistic routing and network coding are regarded as the most promising techniques. While there have been some attempts to combine opportunistic routing with network coding to capture the advantages of both techniques, none of these attempts has considered bit-rate selection for data transmission in multi-rate wireless networks. In this paper, we study the potential benefits of the combination of opportunistic routing and network coding with the bit-rate selection mechanism from an optimization perspective. We develop a theoretical model and algorithm for finding the optimal forwarding scheme for a multi-rate combination of opportunistic routing and network coding in a given network. MIT Roofnet trace-based simulations show that considering bit-rate selection in combination with opportunistic routing and network coding has substantial benefits in terms of the expected transmission time compared to multi-rate opportunistic routing, multi-rate network coding, and a fixed-rate combination approach.
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