The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
Ming Xiao - One of the best experts on this subject based on the ideXlab platform.
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Performance Analysis of Cognitive User Cooperation Using Binary Network Coding
IEEE Transactions on Vehicular Technology, 2018Co-Authors: Lars K. Rasmussen, Ming XiaoAbstract:We consider a cognitive radio Network where a primary and a secondary transmitter, respectively, communicate a message to their primary and secondary receivers over a packet-based wireless link, using a joint automatic-repeat-request (ARQ) error control scheme. The secondary transmitter assists in the retransmission of the primary message, which improves the primary performance, and as a reward it is granted limited access to the transmission resources. Conventional ARQ, as well as two Network-coding schemes are investigated for applications in the retransmission phase; namely the static Network-coding scheme and the adaptive Network-coding scheme. For each scheme we analyze the transmission process by investigating the distribution of the number of transmission attempts. We divide every frame into three transmission sessions and in each session we discover that the number of transmission attempts follows a certain negative binomial distribution, in which case can be further approximated by a normal distribution. Considering both the cases of an adaptive frame size and a truncated frame size, we derive analytical results on system performances and discuss the comparison of three schemes. Besides, the approximation method greatly reduces the complexity of transmission analysis, especially in the truncated frame-size case. Numerical results show that our analysis are valid and closely match the simulations.
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Design of Binary Network Codes for Multiuser Multiway Relay Networks
IEEE Transactions on Vehicular Technology, 2013Co-Authors: Ang Yang, Ming Xiao, Zesong Fei, Chengwen Xing, Jinhong Yuan, Jingming KuangAbstract:We study multiuser multiway relay Networks where N user nodes exchange their information through a single-relay node. We use Network coding (NC) in the relay to increase the throughput. Due to the limitation of complexity, we only consider the Binary multiuser NC (BMNC) in the relay. We study the BMNC matrix [in GF(2)] and propose several design criteria on the BMNC matrix to improve the symbol error probability (SEP) performance. Closed-form expressions of the SEP of the system are provided. Moreover, an upper bound of the SEP is also proposed to provide further insights into system performance. Then, BMNC matrices are designed to minimize error probabilities.
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Design and Analysis of Relay-aided Broadcast using Binary Network Codes
Journal of Communications, 2011Co-Authors: Ming Xiao, Lars K. RasmussenAbstract:We consider a base-station broadcasting a set of order-insensitive packets to a user population over packet-erasure channels. To improve efficiency we propose relay-aided transmission using instantaneously-decodable Binary Network coding. The proposed coding schemes have the benefits of minimal decoding delay and low complexity. We further analyze the performance of the resulting broadcast schemes, and show that significant improvements in transmission efficiency are obtained as compared to previously proposed ARQ and Network-coding-based schemes.
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ICCCN - Relay-Aided Broadcasting with Instantaneously Decodable Binary Network Codes
2011 Proceedings of 20th International Conference on Computer Communications and Networks (ICCCN), 2011Co-Authors: Ming Xiao, Lars K. RasmussenAbstract:We consider a base-station broadcasting a set of order-insensitive packets to a user population over packet-erasure channels. To improve efficiency we propose a relay-aided transmission scheme using instantaneously-decodable Binary Network coding. Our proposed scheme ensures that a coded packet can be immediately decoded at the user side without delay. Moreover, only Binary operations are required in the encoding and decoding processes, which decrease the computational complex. We further analyze the performance of the resulting broadcast scheme, and show that significant improvements in transmission efficiency are obtained as compared to previously proposed ARQ and Network-coding- based schemes.
Fabio Graziosi - One of the best experts on this subject based on the ideXlab platform.
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On Diversity Order and Coding Gain of Multisource Multirelay Cooperative Wireless Networks With Binary Network Coding
IEEE Transactions on Vehicular Technology, 2013Co-Authors: M. Di Renzo, Michela Iezzi, Fabio GraziosiAbstract:In this paper, a multisource multirelay cooperative wireless Network with Binary modulation and Binary Network coding is studied. The system model encompasses 1) a Demodulate-and-Forward (DemF) protocol at the relays, where the received packets are forwarded, regardless of their reliability, and 2) a maximum-likelihood optimum demodulator at the destination, which accounts for possible demodulation errors at the relays. An asymptotically tight and closed-form expression of the end-to-end error probability is derived, which showcases the diversity order and coding gain of each source. Unlike other papers available in the literature, the proposed framework has three main distinguishable features: 1) It is useful for general Network topologies and arbitrary Binary encoding vectors; 2) it shows how Network code and two-hop forwarding protocol affect diversity order and coding gain; and 3) it accounts for realistic fading channels and demodulation errors at the relays. The framework provides four main conclusions: 1) Each source achieves a diversity order equal to the separation vector of the Network code; 2) the design of diversity-achieving Network codes is equivalent to the design of systematic block codes over fully interleaved point-to-point links; 3) the coding gain of each source decreases with the number of mixed packets at the relays; and 4) if the destination cannot take into account demodulation errors at the relays, it loses approximately half of the diversity order. Our theoretical findings are validated through extensive Monte Carlo simulations.
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Error Performance and Diversity Analysis of Multi-Source Multi-Relay Wireless Networks with Binary Network Coding and Cooperative MRC
IEEE Transactions on Wireless Communications, 2013Co-Authors: M. Di Renzo, Michela Iezzi, Fabio GraziosiAbstract:In this paper, we contribute to the theoretical understanding, the design, and the performance evaluation of multi-source multi-relay Network-coded cooperative diversity protocols. These protocols are useful to counteract the spectral inefficiency of repetition-based cooperation. We provide a general analytical framework for analysis and design of wireless Networks using the Demodulate-and-Forward (DemF) protocol with Binary Network Coding (NC) at the relays and Cooperative Maximal Ratio Combining (C-MRC) at the destination. Our system model encompasses an arbitrary number of relays which offer two cooperation levels: i) full-cooperative relays, which postpone the transmission of their own data frames to help the transmission of the sources via DemF relaying and Binary NC; and ii) partial-cooperative relays, which exploit NC to transmit their own data frames along with the packets received from the sources. The relays can apply NC on different subsets of sources, which is shown to provide the sources with unequal diversity orders. Guidelines to choose the packets to be combined, i.e., the Network code, to achieve the desired diversity order are given. Our study shows that partial-cooperative relays provide no contribution to the diversity order of the sources. Theoretical findings and design guidelines are validated through extensive Monte Carlo simulations.
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On the Diversity Order and Coding Gain of Multi-Source Multi-Relay Cooperative Wireless Networks with Binary Network Coding
arXiv: Information Theory, 2011Co-Authors: M. Di Renzo, Michela Iezzi, Fabio GraziosiAbstract:In this paper, a multi-source multi-relay cooperative wireless Network with Binary modulation and Binary Network coding is studied. The system model encompasses: i) a demodulate-and-forward protocol at the relays, where the received packets are forwarded regardless of their reliability; and ii) a maximum-likelihood optimum demodulator at the destination, which accounts for possible demodulations errors at the relays. An asymptotically-tight and closed-form expression of the end-to-end error probability is derived, which clearly showcases diversity order and coding gain of each source. Unlike other papers available in the literature, the proposed framework has three main distinguishable features: i) it is useful for general Network topologies and arbitrary Binary encoding vectors; ii) it shows how Network code and two-hop forwarding protocol affect diversity order and coding gain; and ii) it accounts for realistic fading channels and demodulation errors at the relays. The framework provides three main conclusions: i) each source achieves a diversity order equal to the separation vector of the Network code; ii) the coding gain of each source decreases with the number of mixed packets at the relays; and iii) if the destination cannot take into account demodulation errors at the relays, it loses approximately half of the diversity order.
Philippe Thomas - One of the best experts on this subject based on the ideXlab platform.
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Raman spectra and third-order nonlinear optical Z-scan properties of MO-Nb2O5-TeO2 (M=Zn, Mg, Ca, Sr, Ba) glasses
physica status solidi (c), 2011Co-Authors: T. Hayakawa, T. Suhara, Taiga Fujiwara, M. Nogami, Philippe ThomasAbstract:In this paper, the third-order nonlinear optical susceptibilities, χ(3), of tellurite glasses with MO-Nb2O5-TeO2 system (M= Zn, Mg, Ca, Sr, Ba) was investigated by Zscan measurement using Ti:Sapphire femtosecond laser pulses. The relationship between the nonlinear optical properties and the glass structures, estimated by Raman spectroscopy, was discussed. The experimental results revealed that when alkaline-earth ions (M2+) was doped in Nb2O5-TeO2 Binary Network system the break in TeIVeqOax- TeIV chain structure necessarily occurred but the terminations of -TeIV-Oeq-NbVI-O- + M2+ + -Oax-TeIV- or -TeIV-Oeq - + M2+ + -O-NbVI-Oax-TeIV- were more preferentially induced with an assist of NbO6 polyhedron, which produced TeO3+1 units or stabilized TeIVO4 units.
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Nonlinear optical properties and glass structure for MO–Nb2O5–TeO2 (M = Zn, Mg, Ca, Sr, Ba) glasses
Optical Materials, 2010Co-Authors: T. Hayakawa, M. Nogami, M. Hayakawa, Philippe ThomasAbstract:The third-order nonlinear optical susceptibilities v(3) of tellurite(TeO2)-based ternary glasses of MO–Nb2O5–TeO2 (M = Zn, Mg, Ca, Sr, Ba) were investigated by Z-scan measurement using Ti:Sapphire femtosecond laser pulses. The relationship between the nonlinear optical properties and the glass structures estimated by Raman spectroscopy was discussed. The nonlinear susceptibilities v(3) of these tellurite glasses increased as the stretching Raman band of TeIV–Oax in TeO4 (trigonal bipyramids (tbp), the roman superscript denotes the coordination number) increased, while the stretching band of TeIII–O in TeO3 (trigonal pyramid (tp)) decreased. This indicates that the amount of TeO4 (tbp) units was deeply related to the value of v(3), which was consistent with the theoretical calculation of higher hyperpolarizabilities of TeO4 than TeO3 unit. It was also found that higher v(3) was obtained with decreasing TeIV– eqOax–TeIV Raman band, indicating that when divalent cations (M2+) was doped in Nb2O5–TeO2 Binary Network system the cleavage of TeIV–eqOax–TeIV chain structure necessarily occurred but the terminations of –TeIV–eqO M2+ O–NbVI–Oax–TeIV–, which importantly stabilized TeO4 units even in the presence of the Network modifier M2+, were more preferentially induced with an assist of NbO6 octahedron than –TeIV–eqO M2+ O = TeIII–O–.
M. Di Renzo - One of the best experts on this subject based on the ideXlab platform.
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Multiple-Access Relaying with Network Coding: Iterative Network/Channel Decoding with Imperfect CSI
EURASIP Journal on Advances in Signal Processing, 2013Co-Authors: M. Di Renzo, Pierre DuhamelAbstract:In this paper, we study the performance of the four-node multiple-access relay channel with Binary Network Coding (NC) in various Rayleigh fading scenarios. In particular, two relay protocols, decode-and-forward (DF) and demodulate-and-forward (DMF) are considered. In the first case, channel decoding is performed at the relay before NC and forwarding. In the second case, only demodulation is performed at the relay. The contributions of the paper are as follows: (1) two joint Network/channel decoding (JNCD) algorithms, which take into account possible decoding error at the relay, are developed in both DF and DMF relay protocols; (2) both perfect channel state information (CSI) and imperfect CSI at receivers are studied. In addition, we propose a practical method to forward the relays error characterization to the destination (quantization of the BER). This results in a fully practical scheme. (3) We show by simulation that the number of pilot symbols only affects the coding gain but not the diversity order, and that quantization accuracy affects both coding gain and diversity order. Moreover, when compared with the recent results using DMF protocol, our proposed DF protocol algorithm shows an improvement of 4 dB in fully interleaved Rayleigh fading channels and 0.7 dB in block Rayleigh fading channels.
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On Diversity Order and Coding Gain of Multisource Multirelay Cooperative Wireless Networks With Binary Network Coding
IEEE Transactions on Vehicular Technology, 2013Co-Authors: M. Di Renzo, Michela Iezzi, Fabio GraziosiAbstract:In this paper, a multisource multirelay cooperative wireless Network with Binary modulation and Binary Network coding is studied. The system model encompasses 1) a Demodulate-and-Forward (DemF) protocol at the relays, where the received packets are forwarded, regardless of their reliability, and 2) a maximum-likelihood optimum demodulator at the destination, which accounts for possible demodulation errors at the relays. An asymptotically tight and closed-form expression of the end-to-end error probability is derived, which showcases the diversity order and coding gain of each source. Unlike other papers available in the literature, the proposed framework has three main distinguishable features: 1) It is useful for general Network topologies and arbitrary Binary encoding vectors; 2) it shows how Network code and two-hop forwarding protocol affect diversity order and coding gain; and 3) it accounts for realistic fading channels and demodulation errors at the relays. The framework provides four main conclusions: 1) Each source achieves a diversity order equal to the separation vector of the Network code; 2) the design of diversity-achieving Network codes is equivalent to the design of systematic block codes over fully interleaved point-to-point links; 3) the coding gain of each source decreases with the number of mixed packets at the relays; and 4) if the destination cannot take into account demodulation errors at the relays, it loses approximately half of the diversity order. Our theoretical findings are validated through extensive Monte Carlo simulations.
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Error Performance and Diversity Analysis of Multi-Source Multi-Relay Wireless Networks with Binary Network Coding and Cooperative MRC
IEEE Transactions on Wireless Communications, 2013Co-Authors: M. Di Renzo, Michela Iezzi, Fabio GraziosiAbstract:In this paper, we contribute to the theoretical understanding, the design, and the performance evaluation of multi-source multi-relay Network-coded cooperative diversity protocols. These protocols are useful to counteract the spectral inefficiency of repetition-based cooperation. We provide a general analytical framework for analysis and design of wireless Networks using the Demodulate-and-Forward (DemF) protocol with Binary Network Coding (NC) at the relays and Cooperative Maximal Ratio Combining (C-MRC) at the destination. Our system model encompasses an arbitrary number of relays which offer two cooperation levels: i) full-cooperative relays, which postpone the transmission of their own data frames to help the transmission of the sources via DemF relaying and Binary NC; and ii) partial-cooperative relays, which exploit NC to transmit their own data frames along with the packets received from the sources. The relays can apply NC on different subsets of sources, which is shown to provide the sources with unequal diversity orders. Guidelines to choose the packets to be combined, i.e., the Network code, to achieve the desired diversity order are given. Our study shows that partial-cooperative relays provide no contribution to the diversity order of the sources. Theoretical findings and design guidelines are validated through extensive Monte Carlo simulations.
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On the Diversity Order and Coding Gain of Multi-Source Multi-Relay Cooperative Wireless Networks with Binary Network Coding
arXiv: Information Theory, 2011Co-Authors: M. Di Renzo, Michela Iezzi, Fabio GraziosiAbstract:In this paper, a multi-source multi-relay cooperative wireless Network with Binary modulation and Binary Network coding is studied. The system model encompasses: i) a demodulate-and-forward protocol at the relays, where the received packets are forwarded regardless of their reliability; and ii) a maximum-likelihood optimum demodulator at the destination, which accounts for possible demodulations errors at the relays. An asymptotically-tight and closed-form expression of the end-to-end error probability is derived, which clearly showcases diversity order and coding gain of each source. Unlike other papers available in the literature, the proposed framework has three main distinguishable features: i) it is useful for general Network topologies and arbitrary Binary encoding vectors; ii) it shows how Network code and two-hop forwarding protocol affect diversity order and coding gain; and ii) it accounts for realistic fading channels and demodulation errors at the relays. The framework provides three main conclusions: i) each source achieves a diversity order equal to the separation vector of the Network code; ii) the coding gain of each source decreases with the number of mixed packets at the relays; and iii) if the destination cannot take into account demodulation errors at the relays, it loses approximately half of the diversity order.
T. Hayakawa - One of the best experts on this subject based on the ideXlab platform.
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Raman spectra and third-order nonlinear optical Z-scan properties of MO-Nb2O5-TeO2 (M=Zn, Mg, Ca, Sr, Ba) glasses
physica status solidi (c), 2011Co-Authors: T. Hayakawa, T. Suhara, Taiga Fujiwara, M. Nogami, Philippe ThomasAbstract:In this paper, the third-order nonlinear optical susceptibilities, χ(3), of tellurite glasses with MO-Nb2O5-TeO2 system (M= Zn, Mg, Ca, Sr, Ba) was investigated by Zscan measurement using Ti:Sapphire femtosecond laser pulses. The relationship between the nonlinear optical properties and the glass structures, estimated by Raman spectroscopy, was discussed. The experimental results revealed that when alkaline-earth ions (M2+) was doped in Nb2O5-TeO2 Binary Network system the break in TeIVeqOax- TeIV chain structure necessarily occurred but the terminations of -TeIV-Oeq-NbVI-O- + M2+ + -Oax-TeIV- or -TeIV-Oeq - + M2+ + -O-NbVI-Oax-TeIV- were more preferentially induced with an assist of NbO6 polyhedron, which produced TeO3+1 units or stabilized TeIVO4 units.
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Nonlinear optical properties and glass structure for MO–Nb2O5–TeO2 (M = Zn, Mg, Ca, Sr, Ba) glasses
Optical Materials, 2010Co-Authors: T. Hayakawa, M. Nogami, M. Hayakawa, Philippe ThomasAbstract:The third-order nonlinear optical susceptibilities v(3) of tellurite(TeO2)-based ternary glasses of MO–Nb2O5–TeO2 (M = Zn, Mg, Ca, Sr, Ba) were investigated by Z-scan measurement using Ti:Sapphire femtosecond laser pulses. The relationship between the nonlinear optical properties and the glass structures estimated by Raman spectroscopy was discussed. The nonlinear susceptibilities v(3) of these tellurite glasses increased as the stretching Raman band of TeIV–Oax in TeO4 (trigonal bipyramids (tbp), the roman superscript denotes the coordination number) increased, while the stretching band of TeIII–O in TeO3 (trigonal pyramid (tp)) decreased. This indicates that the amount of TeO4 (tbp) units was deeply related to the value of v(3), which was consistent with the theoretical calculation of higher hyperpolarizabilities of TeO4 than TeO3 unit. It was also found that higher v(3) was obtained with decreasing TeIV– eqOax–TeIV Raman band, indicating that when divalent cations (M2+) was doped in Nb2O5–TeO2 Binary Network system the cleavage of TeIV–eqOax–TeIV chain structure necessarily occurred but the terminations of –TeIV–eqO M2+ O–NbVI–Oax–TeIV–, which importantly stabilized TeO4 units even in the presence of the Network modifier M2+, were more preferentially induced with an assist of NbO6 octahedron than –TeIV–eqO M2+ O = TeIII–O–.