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To solve the problems of low spectral efficiency and poor performance of physical layer security (PLS) in single-input single-output (SISO) wireless systems with adaptive modulation in the presence of an active eavesdropper, multiple-input multiple-output (MIMO) wireless systems with secure adaptive modulation (SAM) were proposed.The design idea was to improve the spectral efficiency of the main channel by antenna diversity technology, which used the transmit antenna selection (TAS) at the transmitter and the maximal ratio combining (MRC) at the legitimate receiver to improve the signal-to-noise ratio.Simultaneously, the PLS of the legitimate receiver was guaranteed by limiting the bit error rate of the active eavesdropper so that it could not demodulate the confidential information from the main channel.With the joint constraints of the average transmission power and PLS, the optimal switching thresholds and the analytical expressions of spectral efficiency and the eavesdropper’s average bit error rate of the SAM-MIMO systems were derived.Numerical and simulation results show that SAM systems using TAS/MRC technology can not only improve the spectral efficiency of the main channel, but also ensure the PLS against the active eavesdropper, compared with the SAM-SISO systems.

Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Telecommunications Science is the property of Beijing Xintong Media Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Guangdong University of Technology is the property of Journal of Guangdong University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Chongqing University of Posts & Telecommunications (Natural Science Edition) is the property of Chongqing University of Posts & Telecommunications and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to maximize the total spectrum efficiency and improve the Quality of Experience (QoE) on Elastic Optical Network (EON), an adaptive modulation method based on Deep Neural Network (DNN) is proposed. Firstly, the network transmission quality in optical fiber is estimated. Then, the route length, hop number and video quality are taken as the three parameters of the request characteristics, and the deep learning method is adopted to selected the modulation system with the maximum spectrum efficiency according to the desired QoE of each requirement. The simulation results show that the average spectral efficiency of the proposed method is 51%and 32%higher in National Science Foundation (NSF) network than that of distance adaptive method and integer programming method, and 43%and 29%higher in China Network (CN) backbone network. In addition, the blocking probability of the proposed method is 0.01 lower than that of the distance adaptive method and integer programming method.

In order to maximize the total spectrum efficiency and improve the Quality of Experience (QoE) on Elastic Optical Network (EON), an adaptive modulation method based on Deep Neural Network (DNN) is proposed. Firstly, the network transmission quality in optical fiber is estimated. Then, the route length, hop number and video quality are taken as the three parameters of the request characteristics, and the deep learning method is adopted to selected the modulation system with the maximum spectrum efficiency according to the desired QoE of each requirement. The simulation results show that the average spectral efficiency of the proposed method is 51%and 32%higher in National Science Foundation (NSF) network than that of distance adaptive method and integer programming method, and 43%and 29%higher in China Network (CN) backbone network. In addition, the blocking probability of the proposed method is 0.01 lower than that of the distance adaptive method and integer programming method.

Copyright of Telecommunication Engineering is the property of Telecommunication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A novel adaptive modulation based on nondata-aided error vector magnitude (NDA-EVM) was proposed to solve the problem of lower spectral efficiency in device to device (D2D) communication over Nakagami-m fading channel.The NDA-EVM was used to evaluate the channel quality.The relationship between NDA-EVM and symbol error ratio (SER) was derived according to the maximum likelihood method.Thereafter,the adaptive modulation mechanism of MQAM with the SER constraint was designed.Considering the joint effect of finite-length queuing and fading channel,the system packet loss rate and spectral efficiency was analyzed.Theoretical analysis and simulation experiments show that NDA-EVM based adaptive modulation accurately gives the modulation threshold and evaluates the relationship between QoS and packet loss rate,the proposed algorithm improves system spectral efficiency while maintaining low algorithm complexity,spectral efficiency improves by 0.752 bit·(s·Hz)-1,compared with traditional algorithm.

Copyright of Telecommunication Engineering is the property of Telecommunication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A novel nondata-aided error vector magnitude based adaptive modulation(NDA-EVM-AM) was proposed to solve the problem of lower spectral efficiency over rapidly time-varying wireless channels.Namely,NDA-EVM was considered as a metric to reflect the rapid change of time-varying channels.The unified model to calculate different modulation order of NDA-EVM was analytically derived,with which the relationship between NDA-EVM and bit error rate (BER) for each modulation order was presented.Thereafter,the mechanism to adaptively select the modulation orders of multilevel quadrature amplitude modulation (MQAM) signals was designed to guarantee the predefined BER.Taking the two rapidly time-varying channels proposed for high-speed railway scenarios as examples,numerical results are conducted to verify the effectiveness of the proposed algorithm.It shows that NDA-EVM estimation has the lest root mean square error than data-aided error vector magnitude (DA-EVM) estimation and signal to noise ratio estimation.The proposed algorithm has better accuracy in aspects of channel quality estimation and modulation orders adjustment,Compared with conventional data-aided error vector magnitude based-adaptive modulation (DA-EVM-AM),the accuracy improves by 7.9%,spectral efficiency improves by 0.53 bit·s−1·Hz−1,and compared with signal to noise ratio based-adaptive modulation (SNR-AM),the accuracy improves by 15.7%,spectral efficiency improves by 0.82 bit·s−1·Hz−1.

Copyright of Journal on Communication / Tongxin Xuebao is the property of Journal on Communications Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to develop die collection efficiency for power utilization information in low voltage power metering area, a high speed, real-time and bilateral intelligent power utilization information collection system is constructed under the demand of limitation for communication unit power consumption defined in Q/GDW 1379. 4-2013 technical specification. A rate maximization algorithm based on sub-bands for power line carrier is proposed. In the algorithm, signal carrier band is 2 ~ 30 MHz. The adaptive sub-carrier modulation based on Homeplug AV statute is combined to make the neighboring sub-carriers be a unit sub-band. The greedy power allocation is assimilated into the average SNR threshold algorithm to allocate the bite on each sub-band which we set so as to acquire the maximal carrier rate. Simulation results show that the algorithm proposed owns a higher carrier rate compared to the classical SNR threshold algorithm and Homeplug AV method. Although it has weaker rate compared to the classical greedy algorithm, it cuts greatly the calculating complexity and hardware consumption. [ABSTRACT FROM AUTHOR]

A high efficiency algorithm of power and bit allocation for OFDMA system was propose,which including three parts: linear water-filling power allocation,bit allocation and power and bit adjustment. It could quickly achieve the power and bit allocation between users,and would not change the fairness performance between users. Simulation results showed that,the proposed algorithm need not iteration and could obviously decrease the operation complexity with a slight descent in system throughput contrast to other algorithms. It was promising to be used in a practical system for radio resource allocation.

In view of the system BER with fixed subband division algorithm is higher, the uniform dynamic subband division algorithm requires multiple iterations and high algorithm complexity, A non-uniform dynamic subband division adaptive modulation algorithm of OFDM is proposed. The algorithm according to the channel frequency response relationship can complete subband dynamic division without iterations. The random selection scheme was defined subband equivalent SNR. The bit adjustment method selected the priority way used the subband with maximum equivalent SNR. The proposed algorithm can reduce iteration number of bit adjustment, thus the complexity is low. The simulation results show that the algorithm compared SBLA algorithm and 4QAM modulation mode can obtain 2 dB, 2.6 dB SNR gain in BER 10-3. [ABSTRACT FROM AUTHOR]

With the extensive application of adaptive modulation and coding techniques (AMC) and low density parity codes (LDPC), identification technology for LDPC in AMC has drawn more and more researchers' attention. For that problem, the existing methods have been suffering weak identification performance, so this paper presents a new recognition algorithm for LDPC in AMC based on maximum deviation ratio. First, the paper defines the log-likelihood ratio (PLLR)of the parity relationship with the soft-decision sequence, and makes some necessary analysis on its module value's probability distribution. Then, using the statistical differences of the parity log-likelihood ratio on the various parity check matrix, a maximum deviation ratio based decision device is proposed, which takes into account both mean and variation properties of PLLR. Simulation results show that the new recognition algorithm can effectively identify the LDPC codes in AMC, even in the low signal-to-noise ratio channel environments. Especially for the high code rate LDPC codes, the new algorithm is better than existing ones. [ABSTRACT FROM AUTHOR]

This paper proposed a multiuser OFDM subcarrier, bit, and power allocation suboptimal algorithm. In consideration of the distribution principle of the optimal algorithm, it selects suitable time frequency blocks for every user and adjusts their modulation levels according to every user's QoS and channel state imformation. The simulation results show that the proposed algorithm has better performance in reducing transmission power. [ABSTRACT FROM AUTHOR]