The Experts below are selected from a list of 75 Experts worldwide ranked by ideXlab platform
Mark M. Wilde - One of the best experts on this subject based on the ideXlab platform.
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ISIT - Polar coding to achieve the Holevo capacity of a pure-loss optical channel
2012 IEEE International Symposium on Information Theory Proceedings, 2012Co-Authors: Saikat Guha, Mark M. WildeAbstract:In the low-energy high-energy-efficiency regime of classical optical communications — relevant to deep-space optical channels — there is a big gap between reliable communication rates achievable via conventional optical receivers and the ultimate (Holevo) capacity. Achieving the Holevo capacity requires not only optimal codes but also receivers that make collective measurements on long (modulated) Codeword waveforms, and it is impossible to implement these collective measurements via symbol-by-symbol detection along with classical postprocessing [1], [2]. Here, we apply our recent results on the classical-quantum polar code [3] — the first near-explicit, linear, symmetric-Holevo-rate achieving code — to the lossy optical channel, and we show that it almost closes the entire gap to the Holevo capacity in the low photon number regime. In contrast, Arikan's original polar codes, applied to the DMC induced by the physical optical channel paired with any conceivable structured optical receiver (including optical homodyne, heterodyne, or direct-detection) fails to achieve the ultimate Holevo limit to channel capacity. However, our polar code construction (which uses the quantum fidelity as a channel parameter rather than the classical Bhattacharyya quantity to choose the “good channels” in the polar-code construction), paired with a quantum successive-cancellation receiver — which involves a sequence of collective non-destructive binary projective measurements on the joint quantum state of the Received Codeword waveform — can attain the Holevo limit, and can hence in principle achieve higher rates than Arikan's polar code and decoder directly applied to the optical channel. However, even a theoretical recipe for construction of an optical realization of the quantum successive-cancellation receiver remains an open question.
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Polar coding to achieve the Holevo capacity of a pure-loss optical channel
IEEE International Symposium on Information Theory - Proceedings, 2012Co-Authors: Saikat Guha, Mark M. WildeAbstract:In the low-energy high-energy-efficiency regime of classical optical communications---relevant to deep-space optical channels---there is a big gap between reliable communication rates achievable via conventional optical receivers and the ultimate (Holevo) capacity. Achieving the Holevo capacity requires not only optimal codes but also receivers that make collective measurements on long (modulated) Codeword waveforms, and it is impossible to implement these collective measurements via symbol-by-symbol detection along with classical postprocessing. Here, we apply our recent results on the classical-quantum polar code---the first near-explicit, linear, symmetric-Holevo-rate achieving code---to the lossy optical channel, and we show that it almost closes the entire gap to the Holevo capacity in the low photon number regime. In contrast, Arikan's original polar codes, applied to the DMC induced by the physical optical channel paired with any conceivable structured optical receiver (including optical homodyne, heterodyne, or direct-detection) fails to achieve the ultimate Holevo limit to channel capacity. However, our polar code construction (which uses the quantum fidelity as a channel parameter rather than the classical Bhattacharyya quantity to choose the "good channels" in the polar-code construction), paired with a quantum successive-cancellation receiver---which involves a sequence of collective non-destructive binary projective measurements on the joint quantum state of the Received Codeword waveform---can attain the Holevo limit, and can hence in principle achieve higher rates than Arikan's polar code and decoder directly applied to the optical channel. However, even a theoretical recipe for construction of an optical realization of the quantum successive-cancellation receiver remains an open question.
Saikat Guha - One of the best experts on this subject based on the ideXlab platform.
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ISIT - Polar coding to achieve the Holevo capacity of a pure-loss optical channel
2012 IEEE International Symposium on Information Theory Proceedings, 2012Co-Authors: Saikat Guha, Mark M. WildeAbstract:In the low-energy high-energy-efficiency regime of classical optical communications — relevant to deep-space optical channels — there is a big gap between reliable communication rates achievable via conventional optical receivers and the ultimate (Holevo) capacity. Achieving the Holevo capacity requires not only optimal codes but also receivers that make collective measurements on long (modulated) Codeword waveforms, and it is impossible to implement these collective measurements via symbol-by-symbol detection along with classical postprocessing [1], [2]. Here, we apply our recent results on the classical-quantum polar code [3] — the first near-explicit, linear, symmetric-Holevo-rate achieving code — to the lossy optical channel, and we show that it almost closes the entire gap to the Holevo capacity in the low photon number regime. In contrast, Arikan's original polar codes, applied to the DMC induced by the physical optical channel paired with any conceivable structured optical receiver (including optical homodyne, heterodyne, or direct-detection) fails to achieve the ultimate Holevo limit to channel capacity. However, our polar code construction (which uses the quantum fidelity as a channel parameter rather than the classical Bhattacharyya quantity to choose the “good channels” in the polar-code construction), paired with a quantum successive-cancellation receiver — which involves a sequence of collective non-destructive binary projective measurements on the joint quantum state of the Received Codeword waveform — can attain the Holevo limit, and can hence in principle achieve higher rates than Arikan's polar code and decoder directly applied to the optical channel. However, even a theoretical recipe for construction of an optical realization of the quantum successive-cancellation receiver remains an open question.
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Polar coding to achieve the Holevo capacity of a pure-loss optical channel
IEEE International Symposium on Information Theory - Proceedings, 2012Co-Authors: Saikat Guha, Mark M. WildeAbstract:In the low-energy high-energy-efficiency regime of classical optical communications---relevant to deep-space optical channels---there is a big gap between reliable communication rates achievable via conventional optical receivers and the ultimate (Holevo) capacity. Achieving the Holevo capacity requires not only optimal codes but also receivers that make collective measurements on long (modulated) Codeword waveforms, and it is impossible to implement these collective measurements via symbol-by-symbol detection along with classical postprocessing. Here, we apply our recent results on the classical-quantum polar code---the first near-explicit, linear, symmetric-Holevo-rate achieving code---to the lossy optical channel, and we show that it almost closes the entire gap to the Holevo capacity in the low photon number regime. In contrast, Arikan's original polar codes, applied to the DMC induced by the physical optical channel paired with any conceivable structured optical receiver (including optical homodyne, heterodyne, or direct-detection) fails to achieve the ultimate Holevo limit to channel capacity. However, our polar code construction (which uses the quantum fidelity as a channel parameter rather than the classical Bhattacharyya quantity to choose the "good channels" in the polar-code construction), paired with a quantum successive-cancellation receiver---which involves a sequence of collective non-destructive binary projective measurements on the joint quantum state of the Received Codeword waveform---can attain the Holevo limit, and can hence in principle achieve higher rates than Arikan's polar code and decoder directly applied to the optical channel. However, even a theoretical recipe for construction of an optical realization of the quantum successive-cancellation receiver remains an open question.
Mohammad A Khojastepour - One of the best experts on this subject based on the ideXlab platform.
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ldpc code design for half duplex cooperative relay
IEEE Transactions on Wireless Communications, 2008Co-Authors: Guosen Yue, Xiaodong Wang, Mohammad A KhojastepourAbstract:The authors consider the design of LDPC codes for cooperative relay systems in the half-duplex mode. The capacity of halfduplex relay channels has been studied previously but the design of good channel codes for such channels remains a challenging problem. Employing an efficient relay protocol, we transform the half-duplex relay code design problem into a problem of ratecompatible LDPC code design where different code segments experience different SNRs. The density evolution with conventional Gaussian approximation for single user channels, which assumes invariant SNR within one Codeword, is not capable of accurately predicting the code performance for this system. Here we develop a density evolution with a modified Gaussian approximation that takes into account the SNR variation in one Received Codeword as well as the rate-compatibility constraint. We then optimize the code ensemble using a modified differential evolution procedure. Extensive simulations are carried out to demonstrate that the proposed algorithm offers more accurate prediction of code performance in half-duplex relay channels than the conventional methods, and the optimized codes achieve a significant gain over existing codes.
Guosen Yue - One of the best experts on this subject based on the ideXlab platform.
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ldpc code design for half duplex cooperative relay
IEEE Transactions on Wireless Communications, 2008Co-Authors: Guosen Yue, Xiaodong Wang, Mohammad A KhojastepourAbstract:The authors consider the design of LDPC codes for cooperative relay systems in the half-duplex mode. The capacity of halfduplex relay channels has been studied previously but the design of good channel codes for such channels remains a challenging problem. Employing an efficient relay protocol, we transform the half-duplex relay code design problem into a problem of ratecompatible LDPC code design where different code segments experience different SNRs. The density evolution with conventional Gaussian approximation for single user channels, which assumes invariant SNR within one Codeword, is not capable of accurately predicting the code performance for this system. Here we develop a density evolution with a modified Gaussian approximation that takes into account the SNR variation in one Received Codeword as well as the rate-compatibility constraint. We then optimize the code ensemble using a modified differential evolution procedure. Extensive simulations are carried out to demonstrate that the proposed algorithm offers more accurate prediction of code performance in half-duplex relay channels than the conventional methods, and the optimized codes achieve a significant gain over existing codes.
Xiaodong Wang - One of the best experts on this subject based on the ideXlab platform.
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ldpc code design for half duplex cooperative relay
IEEE Transactions on Wireless Communications, 2008Co-Authors: Guosen Yue, Xiaodong Wang, Mohammad A KhojastepourAbstract:The authors consider the design of LDPC codes for cooperative relay systems in the half-duplex mode. The capacity of halfduplex relay channels has been studied previously but the design of good channel codes for such channels remains a challenging problem. Employing an efficient relay protocol, we transform the half-duplex relay code design problem into a problem of ratecompatible LDPC code design where different code segments experience different SNRs. The density evolution with conventional Gaussian approximation for single user channels, which assumes invariant SNR within one Codeword, is not capable of accurately predicting the code performance for this system. Here we develop a density evolution with a modified Gaussian approximation that takes into account the SNR variation in one Received Codeword as well as the rate-compatibility constraint. We then optimize the code ensemble using a modified differential evolution procedure. Extensive simulations are carried out to demonstrate that the proposed algorithm offers more accurate prediction of code performance in half-duplex relay channels than the conventional methods, and the optimized codes achieve a significant gain over existing codes.
