Energy and throughput optimization occupies an important place in the research area of Wireless Sensor Networks (WSNs). These networks are a class of useful but challenging networks. Combining Network coding (NC) and ...
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ISBN:
(纸本)9781467387590
Energy and throughput optimization occupies an important place in the research area of Wireless Sensor Networks (WSNs). These networks are a class of useful but challenging networks. Combining Network coding (NC) and efficient scheduling in the MAC layer of such networks gives more efficiency and copes with the problem of energy waste and inefficiency management as well as transmission's lose and collision. Our work's concern is to assess the contribution of the network coding technique's introduction to improve the efficiency and optimize the energy consumption in the MAC layer of IR-UWB based WSNs. Therefore, we tested this new technique using WideMac Protocol;which is a relevant MAC protocols dedicated to WSNs based on IR-UWB. Furthermore, we used xor coding to fit low computational capabilities requirement in such networks. The obtained results are very encouraging and the proposed MAC scheme's improvements have demonstrated the positive impact of using NC in terms of both used metrics.
TCP over wireless networks is challenging due to random losses and DATA-ACK interference. Random linear coding schemes have been proposed to improve TCP robustness against extreme random losses, but a critical issue s...
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ISBN:
(纸本)9781467300810
TCP over wireless networks is challenging due to random losses and DATA-ACK interference. Random linear coding schemes have been proposed to improve TCP robustness against extreme random losses, but a critical issue still remains of DATA-ACK interference. To address this problem, we use inter-flow coding between DATA and ACK at potential intersecting nodes to mitigate self-interference. In addition, a pipelined random linear coding scheme with adaptive redundancy is introduced to overcome high loss rates over unreliable links. The resulting coding scheme, Combocoding, combines inter-flow and intra-flow coding to provide robust, fair TCP communication in multi-flow disruptive wireless networks. Simulation results show that TCP with Combocoding delivers higher throughput than other coding options in high loss scenarios. Moreover, we study the behavior of multiple TCP flows intersecting and interfering with each other in the same ad hoc network. The results show that Combocoding consistently provides better fairness among multiple co-existing TCP sessions when compared with TCP without coding. The main contributions of this paper are: the practical design of random linear coded packets and xor coded packets on bi-directional streams (DATA and ACK), the adaptive redundancy control scheme, and the multiple coded TCP sessions fairness evaluation.
With the rapid development of wireless network and multimedia technology, the efficient transmission over unreliable channel is becoming more and more important. The error control technique for video coding and transm...
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ISBN:
(纸本)9781509017812
With the rapid development of wireless network and multimedia technology, the efficient transmission over unreliable channel is becoming more and more important. The error control technique for video coding and transmission has drawn considerable attention, tries to recover the data loss and bit errors due to congestion or physical channel fading. Currently, there are three kinds of error control schemes, namely, error resilient coding at the encoder, error concealment at the decoder and the retransmission in the transport layer. In this paper, an error control scheme is proposed which uses the soft information in channel decoding to recover the corrupted bit stream. When bit error is detected in a slice, soft information of channel decoding is employed to locate it, and the wrong bits are flipped and decoded again at the beginning of the slice. The combination of xor at source and the syntax checking of H.264 decoder has increased the error detection rate from around 60% to 99% without increasing source redundancy. Simulation results show that, when the same error concealing algorithm is used, the PSNR of the proposed scheme using soft information of channel decoding at the decoder is 1-2dB higher than that using the traditional method.
TCP over Mobile Ad-hoc Networks (MANETs) is challenging due to frequent route breaks, high random errors, and DATA-ACK interference. Network coded multipath approaches have been shown in several previous studies to be...
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ISBN:
(纸本)9781467324335;9781467324328
TCP over Mobile Ad-hoc Networks (MANETs) is challenging due to frequent route breaks, high random errors, and DATA-ACK interference. Network coded multipath approaches have been shown in several previous studies to be an effective transmission paradigms in disruptive networks. However, most of the previous studies either have no adaptive redundancy control or rely on theoretical models that require knowledge at all relays of the entire network state. In this paper, we propose a network coded multipath scheme for conventional TCP-CodeMP-that adapts to frequent link changes in MANET and requires no explicit control messages. The scheme exploits multiple-path redundancy and maintains total transparency to transport layer protocols. The proposed coding scheme is based on three components: (1) random linear coding scheme with adjustable redundancy, (2) multipath routing, (3) ACK Piggy coding. Simulation results show that in a 3-hop static scenario, the proposed multipath scheme improves TCP flows goodput by 70% compared to our previous single-path scheme. In an extreme MANET scenario where two TCP sessions co-exists and nodes are moving as fast as 25 m/s with up to 40% packet error rate (an environment in which regular TCP collapses completely), CodeMP achieves at least 700Kbps aggregate TCP goodput, with a Jain's fairness index of 0.99.
Energy and throughput optimization occupies an important place in the research area of Wireless Sensor Networks (WSNs). These networks are a class of useful but challenging networks. Combining Network coding (NC) and ...
详细信息
Energy and throughput optimization occupies an important place in the research area of Wireless Sensor Networks (WSNs). These networks are a class of useful but challenging networks. Combining Network coding (NC) and efficient scheduling in the MAC layer of such networks gives more efficiency and copes with the problem of energy waste and inefficiency management as well as transmission's lose and collision. Our work's concern is to assess the contribution of the network coding technique's introduction to improve the efficiency and optimize the energy consumption in the MAC layer of IR-UWB based WSNs. Therefore, we tested this new technique using WideMac Protocol;which is a relevant MAC protocols dedicated to WSNs based on IR-UWB. Furthermore, we used xor coding to fit low computational capabilities requirement in such networks. The obtained results are very encouraging and the proposed MAC scheme's improvements have demonstrated the positive impact of using NC in terms of both used metrics.
With the rapid development of wireless network and multimedia technology,the efficient transmission over unreliable channel is becoming more and more *** error control technique for video coding and transmission has d...
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With the rapid development of wireless network and multimedia technology,the efficient transmission over unreliable channel is becoming more and more *** error control technique for video coding and transmission has drawn considerable attention,tries to recover the data loss and bit errors due to congestion or physical channel ***,there are three kinds of error control schemes,namely,error resilient coding at the encoder,error concealment at the decoder and the retransmission in the transport *** this paper,an error control scheme is proposed which uses the soft information in channel decoding to recover the corrupted bit *** bit error is detected in a slice,soft information of channel decoding is employed to locate it,and the wrong bits are flipped and decoded again at the beginning of the *** combination of xor at source and the syntax checking of H.264 decoder has increased the error detection rate from around 60%to 99%without increasing source *** results show that,when the same error concealing algorithm is used,the PSNR of the proposed scheme using soft information of channel decoding at the decoder is 1-2dB higher than that using the traditional method.
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