The Experts below are selected from a list of 15336 Experts worldwide ranked by ideXlab platform
Mamoru Sawahashi - One of the best experts on this subject based on the ideXlab platform.
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performance of fde using Cyclic Shifted cdm based pilot signal multiplexing for single carrier los mimo
Vehicular Technology Conference, 2019Co-Authors: Kana Aono, Bin Zheng, Mamoru Sawahashi, Norifumi KamiyaAbstract:This paper presents the bit error rate (BER) performance of frequency domain equalization (FDE) using Cyclic-Shifted code division multiplexing (CDM) pilot signals for single-carrier line-of- sight (LOS) - multiple-input multiple-output (MIMO) multiplexing. We use different Cyclic-Shift resources of the same Zadoff-Chu sequence for transmission-stream-specific pilot signals that are essential for estimating the channel response for FDE and phase noise in LOS-MIMO. Computer simulation results show that the required received signal-to-noise power ratio satisfying the BER of 10^(-4) by averaging approximately 4 channel responses after despreading the pilot signal in the frequency domain is decreased by approximately 2.0 dB compared to that without averaging of the channel response for 256QAM, 1024QAM, and 4096QAM in 2x2 and 4x4 LOS-MIMO. Through the simulation results, we show that CDM-based pilot signal multiplexing with different Cyclic Shifts and the frequency domain averaging of the estimated channel response are effective in achieving accurate channel estimation with a short delay and a low pilot-overhead loss for single-carrier LOS- MIMO.
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Orthogonal Pilot Channel Using Combination of FDMA and CDMA in Single-Carrier FDMA-Based Evolved UTRA Uplink
IEICE Transactions on Communications, 2008Co-Authors: Teruo Kawamura, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru SawahashiAbstract:In the Evolved UTRA (UMTS Terrestrial Radio Access) uplink, single-carrier frequency division multiple access (SC-FDMA) radio access was adopted owing to its advantageous low peak-to-average power ratio (PAPR) feature, which leads to wide coverage area provisioning with limited peak transmission power of user equipments. This paper proposes orthogonal pilot channel generation using the combination of FDMA and CDMA in the SC-FDMA-based Evolved UTRA uplink. In the proposed method, we employ distributed FDMA transmission for simultaneous accessing users with different transmission bandwidths, and employ CDMA transmission for simultaneous accessing users with identical transmission bandwidth. Moreover, we apply a code sequence with a good auto-correlation property such as a Constant Amplitude Zero Auto-Correlation (CAZAC) sequence employing a Cyclic Shift to increase the number of sequences. Simulation results show that the average packet error rate performance using an orthogonal pilot channel with the combination of FDMA and CDMA in a six-user environment, i. e., four users each with a 1.25-MHz transmission bandwidth and two users each with a 5-MHz transmission bandwidth, employing turbo coding with the coding r of R=1/2 and QPSK and 16QAM data modulation coincides well with that in a single-user environment with the same transmission bandwidth. We show that the proposed orthogonal pilot channel structure using the combination of distributed FDMA and CDMA transmissions and the application of the CAZAC sequence is effective in the SC-FDMA-based Evolved UTRA uplink.
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orthogonal pilot channel using combination of fdma and cdma in single carrier fdma based evolved utra uplink
Wireless Communications and Networking Conference, 2007Co-Authors: Teruo Kawamura, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru SawahashiAbstract:In the evolved UTRA (UMTS terrestrial radio access) uplink, single-carrier frequency division multiple access (SC-FDMA) radio access was adopted owing to its advantageous low peak-to-average power ratio (PAPR) feature, which leads to wide coverage area provisioning with limited peak transmission power of a set of user equipment (UE). This paper proposes orthogonal pilot channel generation using the combination of FDMA and CDMA in the SC-FDMA-based evolved UTRA uplink. In the proposed method, we employ distributed FDMA transmission for simultaneous accessing users with different transmission bandwidths, and employ CDMA transmission for simultaneous accessing users with identical transmission bandwidths. Moreover, we apply a code sequence with a good auto-correlation property such as a constant amplitude zero auto-correlation (CAZAC) sequence employing a Cyclic Shift to increase the number of sequences. Simulation results show that the average packet error rate (PER) performance using an orthogonal pilot channel with the combination of FDMA and CDMA in a six-user environment, i.e., four users each with a 1.25-MHz transmission bandwidth and two users each with a 5-MHz transmission bandwidth, employing turbo coding with the coding rate of R = 1/2 and QPSK and 16QAM data modulation coincide well with those in a single-UE environment with the same transmission bandwidth. We show that the proposed orthogonal pilot channel structure using the combination of distributed FDMA and CDMA transmissions and the application of the CAZAC sequence is effective in the SC-FDMA-based evolved UTRA uplink.
Xingyuan Wang - One of the best experts on this subject based on the ideXlab platform.
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a novel chaotic algorithm for image encryption utilizing one time pad based on pixel level and dna level
Optics and Lasers in Engineering, 2020Co-Authors: Xingyuan Wang, Yu Wang, Xiaoqiang Zhu, Chao LuoAbstract:Abstract This paper proposes a new chaotic image encryption, which is based on the coupled map lattices (CML system) and DNA diffusion sequences, and it's also a new one-time pad scheme. The initial values and control parameters of the CML system and logistics map are served as keys for one-time pad and calculated by utilizing the SHA-256 hash algorithm and the plaintext. In the pixel level, we utilize the CML system and sort function to encrypt according to the way from diffusion to scrambling; each pixel is encrypted by randomly DNA encoding, it means that a pixel consists of 4 bases in the DNA level; the Hamming distance and Cyclic Shift function are utilized to scramble, and the DNA encoding rules, the DNA complementary rules, the DNA operation rules and other operations are combined with the chaotic map for the diffusion process. Security analysis shows that the new algorithm has good security and can resist common attacks.
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fast image encryption algorithm based on parallel computing system
Information Sciences, 2019Co-Authors: Xingyuan Wang, Le Feng, Hongyu ZhaoAbstract:Abstract To ensure security, image encryption algorithms generally include two stages: permutation and diffusion. The traditional image permutation algorithms include the sort-based permutation algorithm, Arnold-based permutation algorithm, Baker-based permutation algorithm and the Cyclic Shift permutation algorithm, etc. However, these algorithms have the disadvantages of either high time complexity or poor permutation performance. Therefore, in combination with Cyclic Shift and sorting, this paper proposes a permutation algorithm that can not only guarantees good permutation performance but also guarantee low time and space complexity. Most importantly, this paper proposes a parallel diffusion method. This method ensures the parallelism of diffusion to the utmost extent and achieves a qualitative improvement in efficiency over traditional streaming diffusion methods. Finally, combined with the proposed permutation and diffusion, the paper proposes a computational model for parallel image encryption algorithms.
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a novel chaotic image encryption scheme based on hash function and Cyclic Shift
Iete Technical Review, 2019Co-Authors: Xingyuan Wang, Siwei Wang, Na Wei, Yingqian ZhangAbstract:A novel chaotic image encryption scheme based on hash function and Cyclic Shift is designed. The key streams are dependent on the hash value of the plain text and changed in every encryption proces...
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image encryption algorithm based on multiple mixed hash functions and Cyclic Shift
Optics and Lasers in Engineering, 2017Co-Authors: Xingyuan Wang, Xiaoqiang Zhu, Yingqian ZhangAbstract:Abstract This paper proposes a new one-time pad scheme for chaotic image encryption that is based on the multiple mixed hash functions and the Cyclic-Shift function. The initial value is generated using both information of the plaintext image and the chaotic sequences, which are calculated from the SHA1 and MD5 hash algorithms. The scrambling sequences are generated by the nonlinear equations and logistic map. This paper aims to improve the deficiencies of traditional Baptista algorithms and its improved algorithms. We employ the Cyclic-Shift function and piece-wise linear chaotic maps (PWLCM), which give each Shift number the characteristics of chaos, to diffuse the image. Experimental results and security analysis show that the new scheme has better security and can resist common attacks.
Sennur Ulukus - One of the best experts on this subject based on the ideXlab platform.
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wiretap channels implications of the more capable condition and Cyclic Shift symmetry
IEEE Transactions on Information Theory, 2013Co-Authors: Omur Ozel, Sennur UlukusAbstract:Characterization of the rate-equivocation region of a general wiretap channel involves two auxiliary random variables: $U$ , for rate splitting and $V$ , for channel prefixing. In this paper, we explore specific classes of wiretap channels for which the evaluation of the rate-equivocation region is simpler. We show that if the wiretap channel is more capable, $V=X$ is optimal and the boundary of the rate-equivocation region is achieved by varying rate splitting $U$ alone. Conversely, we show under a mild condition that if the wiretap channel is not more capable, then $V=X$ is strictly suboptimal. Next, we focus on the class of Cyclic Shift symmetric wiretap channels. We show that optimal rate splitting $U$ that achieves the boundary of the rate-equivocation region is uniform with cardinality $\vert{\cal X}\vert$ and the prefix channel between optimal $U$ and $V$ is expressed as Cyclic Shifts of the solution of an auxiliary optimization problem over a single variable. We provide a special class of Cyclic Shift symmetric wiretap channels for which $U=\phi$ is optimal. We apply our results to the binary-input Cyclic Shift symmetric wiretap channels and thoroughly characterize the rate-equivocation regions of the BSC-BEC and BEC-BSC wiretap channels.
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wiretap channels implications of the more capable condition and Cyclic Shift symmetry
arXiv: Information Theory, 2011Co-Authors: Omur Ozel, Sennur UlukusAbstract:Characterization of the rate-equivocation region of a general wiretap channel involves two auxiliary random variables: U, for rate splitting and V, for channel prefixing. Evaluation of regions involving auxiliary random variables is generally difficult. In this paper, we explore specific classes of wiretap channels for which the expression and evaluation of the rate-equivocation region are simpler. In particular, we show that when the main channel is more capable than the eavesdropping channel, V=X is optimal and the boundary of the rate-equivocation region can be achieved by varying U alone. Conversely, we show under a mild condition that if the main receiver is not more capable, then V=X is strictly suboptimal. Next, we focus on the class of Cyclic Shift symmetric wiretap channels. We explicitly determine the optimal selections of rate splitting U and channel prefixing V that achieve the boundary of the rate-equivocation region. We show that optimal U and V are determined via Cyclic Shifts of the solution of an auxiliary optimization problem that involves only one auxiliary random variable. In addition, we provide a sufficient condition for Cyclic Shift symmetric wiretap channels to have U=\phi as an optimal selection. Finally, we apply our results to the binary-input Cyclic Shift symmetric wiretap channels. We solve the corresponding constrained optimization problem by inspecting each point of the I(X;Y)-I(X;Z) function. We thoroughly characterize the rate-equivocation regions of the BSC-BEC and BEC-BSC wiretap channels. In particular, we find that U=\phi is optimal and the boundary of the rate-equivocation region is achieved by varying V alone for the BSC-BEC wiretap channel.
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wiretap channels roles of rate splitting and channel prefixing
International Symposium on Information Theory, 2011Co-Authors: Omur Ozel, Sennur UlukusAbstract:Csiszar and Korner's characterization of the rate-equivocation region of a general wiretap channel involves two auxiliary random variables: U, which represents rate splitting and V, which represents channel prefixing. For some channels, one or both of these auxiliary random variables are unnecessary, simplifying the expression and evaluation of the rate-equivocation region. In this paper, we provide new conditions under which channel prefixing or rate splitting does not improve the rate-equivocation region. In particular, we show that when the main channel is more capable than the eavesdropping channel, channel prefixing is unnecessary; the entire rate-equivocation region can be achieved by rate splitting alone. Conversely, we show under a mild assumption that if the main receiver is not more capable, then channel prefixing is strictly necessary. Moreover, we show that if the main channel is more capable but not less noisy, then rate splitting is strictly necessary. Next, we focus on the set of Cyclic Shift symmetric channels. We prove that for these channels, if in addition I(X; Y) − I(X;Z) is maximized at the uniform distribution, then rate splitting is unnecessary. Our results apply to BSC-BEC and BEC-BSC wiretap channels. We identify the conditions on the parameters of the BSC and BEC under which channel prefixing and/or rate splitting are unnecessary.
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rate equivocation region of Cyclic Shift symmetric wiretap channels
Allerton Conference on Communication Control and Computing, 2011Co-Authors: Omur Ozel, Sennur UlukusAbstract:In this paper, we study Cyclic Shift symmetric wiretap channels in which the channels between Alice and Bob and Alice and Eve are both Cyclic Shift symmetric. We characterize the rate-equivocation region by determining the optimal selection of rate splitting U and channel prefixing V for these channels. We show that optimal U and V are determined via Cyclic Shifts of the solution of an auxiliary optimization problem that involves only one auxiliary random variable. We find the cardinality bound on the necessary auxiliary variable and formulate the problem as a constrained optimization problem. We determine the optimality conditions for the binary-input Cyclic Shift symmetric wiretap channels. We find the optimum by inspecting each point of the I(X; Y) — I(X; Z) function and ruling out the sub-optimal candidates that satisfy the optimality conditions. In particular, we address BSC-BEC and BEC-BSC wiretap channels. By using the optimality conditions, we determine the optimal selections of U and V for the rate-equivocation regions of these channels.
Teruo Kawamura - One of the best experts on this subject based on the ideXlab platform.
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Orthogonal Pilot Channel Using Combination of FDMA and CDMA in Single-Carrier FDMA-Based Evolved UTRA Uplink
IEICE Transactions on Communications, 2008Co-Authors: Teruo Kawamura, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru SawahashiAbstract:In the Evolved UTRA (UMTS Terrestrial Radio Access) uplink, single-carrier frequency division multiple access (SC-FDMA) radio access was adopted owing to its advantageous low peak-to-average power ratio (PAPR) feature, which leads to wide coverage area provisioning with limited peak transmission power of user equipments. This paper proposes orthogonal pilot channel generation using the combination of FDMA and CDMA in the SC-FDMA-based Evolved UTRA uplink. In the proposed method, we employ distributed FDMA transmission for simultaneous accessing users with different transmission bandwidths, and employ CDMA transmission for simultaneous accessing users with identical transmission bandwidth. Moreover, we apply a code sequence with a good auto-correlation property such as a Constant Amplitude Zero Auto-Correlation (CAZAC) sequence employing a Cyclic Shift to increase the number of sequences. Simulation results show that the average packet error rate performance using an orthogonal pilot channel with the combination of FDMA and CDMA in a six-user environment, i. e., four users each with a 1.25-MHz transmission bandwidth and two users each with a 5-MHz transmission bandwidth, employing turbo coding with the coding r of R=1/2 and QPSK and 16QAM data modulation coincides well with that in a single-user environment with the same transmission bandwidth. We show that the proposed orthogonal pilot channel structure using the combination of distributed FDMA and CDMA transmissions and the application of the CAZAC sequence is effective in the SC-FDMA-based Evolved UTRA uplink.
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orthogonal pilot channel using combination of fdma and cdma in single carrier fdma based evolved utra uplink
Wireless Communications and Networking Conference, 2007Co-Authors: Teruo Kawamura, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru SawahashiAbstract:In the evolved UTRA (UMTS terrestrial radio access) uplink, single-carrier frequency division multiple access (SC-FDMA) radio access was adopted owing to its advantageous low peak-to-average power ratio (PAPR) feature, which leads to wide coverage area provisioning with limited peak transmission power of a set of user equipment (UE). This paper proposes orthogonal pilot channel generation using the combination of FDMA and CDMA in the SC-FDMA-based evolved UTRA uplink. In the proposed method, we employ distributed FDMA transmission for simultaneous accessing users with different transmission bandwidths, and employ CDMA transmission for simultaneous accessing users with identical transmission bandwidths. Moreover, we apply a code sequence with a good auto-correlation property such as a constant amplitude zero auto-correlation (CAZAC) sequence employing a Cyclic Shift to increase the number of sequences. Simulation results show that the average packet error rate (PER) performance using an orthogonal pilot channel with the combination of FDMA and CDMA in a six-user environment, i.e., four users each with a 1.25-MHz transmission bandwidth and two users each with a 5-MHz transmission bandwidth, employing turbo coding with the coding rate of R = 1/2 and QPSK and 16QAM data modulation coincide well with those in a single-UE environment with the same transmission bandwidth. We show that the proposed orthogonal pilot channel structure using the combination of distributed FDMA and CDMA transmissions and the application of the CAZAC sequence is effective in the SC-FDMA-based evolved UTRA uplink.
Omur Ozel - One of the best experts on this subject based on the ideXlab platform.
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wiretap channels implications of the more capable condition and Cyclic Shift symmetry
IEEE Transactions on Information Theory, 2013Co-Authors: Omur Ozel, Sennur UlukusAbstract:Characterization of the rate-equivocation region of a general wiretap channel involves two auxiliary random variables: $U$ , for rate splitting and $V$ , for channel prefixing. In this paper, we explore specific classes of wiretap channels for which the evaluation of the rate-equivocation region is simpler. We show that if the wiretap channel is more capable, $V=X$ is optimal and the boundary of the rate-equivocation region is achieved by varying rate splitting $U$ alone. Conversely, we show under a mild condition that if the wiretap channel is not more capable, then $V=X$ is strictly suboptimal. Next, we focus on the class of Cyclic Shift symmetric wiretap channels. We show that optimal rate splitting $U$ that achieves the boundary of the rate-equivocation region is uniform with cardinality $\vert{\cal X}\vert$ and the prefix channel between optimal $U$ and $V$ is expressed as Cyclic Shifts of the solution of an auxiliary optimization problem over a single variable. We provide a special class of Cyclic Shift symmetric wiretap channels for which $U=\phi$ is optimal. We apply our results to the binary-input Cyclic Shift symmetric wiretap channels and thoroughly characterize the rate-equivocation regions of the BSC-BEC and BEC-BSC wiretap channels.
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wiretap channels implications of the more capable condition and Cyclic Shift symmetry
arXiv: Information Theory, 2011Co-Authors: Omur Ozel, Sennur UlukusAbstract:Characterization of the rate-equivocation region of a general wiretap channel involves two auxiliary random variables: U, for rate splitting and V, for channel prefixing. Evaluation of regions involving auxiliary random variables is generally difficult. In this paper, we explore specific classes of wiretap channels for which the expression and evaluation of the rate-equivocation region are simpler. In particular, we show that when the main channel is more capable than the eavesdropping channel, V=X is optimal and the boundary of the rate-equivocation region can be achieved by varying U alone. Conversely, we show under a mild condition that if the main receiver is not more capable, then V=X is strictly suboptimal. Next, we focus on the class of Cyclic Shift symmetric wiretap channels. We explicitly determine the optimal selections of rate splitting U and channel prefixing V that achieve the boundary of the rate-equivocation region. We show that optimal U and V are determined via Cyclic Shifts of the solution of an auxiliary optimization problem that involves only one auxiliary random variable. In addition, we provide a sufficient condition for Cyclic Shift symmetric wiretap channels to have U=\phi as an optimal selection. Finally, we apply our results to the binary-input Cyclic Shift symmetric wiretap channels. We solve the corresponding constrained optimization problem by inspecting each point of the I(X;Y)-I(X;Z) function. We thoroughly characterize the rate-equivocation regions of the BSC-BEC and BEC-BSC wiretap channels. In particular, we find that U=\phi is optimal and the boundary of the rate-equivocation region is achieved by varying V alone for the BSC-BEC wiretap channel.
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wiretap channels roles of rate splitting and channel prefixing
International Symposium on Information Theory, 2011Co-Authors: Omur Ozel, Sennur UlukusAbstract:Csiszar and Korner's characterization of the rate-equivocation region of a general wiretap channel involves two auxiliary random variables: U, which represents rate splitting and V, which represents channel prefixing. For some channels, one or both of these auxiliary random variables are unnecessary, simplifying the expression and evaluation of the rate-equivocation region. In this paper, we provide new conditions under which channel prefixing or rate splitting does not improve the rate-equivocation region. In particular, we show that when the main channel is more capable than the eavesdropping channel, channel prefixing is unnecessary; the entire rate-equivocation region can be achieved by rate splitting alone. Conversely, we show under a mild assumption that if the main receiver is not more capable, then channel prefixing is strictly necessary. Moreover, we show that if the main channel is more capable but not less noisy, then rate splitting is strictly necessary. Next, we focus on the set of Cyclic Shift symmetric channels. We prove that for these channels, if in addition I(X; Y) − I(X;Z) is maximized at the uniform distribution, then rate splitting is unnecessary. Our results apply to BSC-BEC and BEC-BSC wiretap channels. We identify the conditions on the parameters of the BSC and BEC under which channel prefixing and/or rate splitting are unnecessary.
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rate equivocation region of Cyclic Shift symmetric wiretap channels
Allerton Conference on Communication Control and Computing, 2011Co-Authors: Omur Ozel, Sennur UlukusAbstract:In this paper, we study Cyclic Shift symmetric wiretap channels in which the channels between Alice and Bob and Alice and Eve are both Cyclic Shift symmetric. We characterize the rate-equivocation region by determining the optimal selection of rate splitting U and channel prefixing V for these channels. We show that optimal U and V are determined via Cyclic Shifts of the solution of an auxiliary optimization problem that involves only one auxiliary random variable. We find the cardinality bound on the necessary auxiliary variable and formulate the problem as a constrained optimization problem. We determine the optimality conditions for the binary-input Cyclic Shift symmetric wiretap channels. We find the optimum by inspecting each point of the I(X; Y) — I(X; Z) function and ruling out the sub-optimal candidates that satisfy the optimality conditions. In particular, we address BSC-BEC and BEC-BSC wiretap channels. By using the optimality conditions, we determine the optimal selections of U and V for the rate-equivocation regions of these channels.
