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Time-domain clustered transmit power adaptation for OFDM system in fading channels
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作者 甘小莺 徐友云 +1 位作者 管云峰 宋文涛 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第2期135-140,共6页
This paper proposes a time-domain clustered transmitter power adaptation scheme for orthogonal frequency division multiplexing (OFDM) system, which can significantly reduce the feedback amount during power adaptation ... This paper proposes a time-domain clustered transmitter power adaptation scheme for orthogonal frequency division multiplexing (OFDM) system, which can significantly reduce the feedback amount during power adaptation comparison with conventional frequency-domain adaptation schemes. It was found that the cluster size plays an important role on the adaptation performance, especially for the vehicular environment. Simulation results showed that using Lagrange interpolation to obtain an explicit curve of Doppler frequency vs cluster size yields good trade-off between the resulted bit error rate (BER) and the amount of feedback. 展开更多
关键词 Power adaptation Orthogonal frequency division multiplexing (OFDM) time-domain cluster Coherence time
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Time–energy high-dimensional one-side device-independent quantum key distribution
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作者 包海泽 鲍皖苏 +4 位作者 汪洋 陈瑞柯 马鸿鑫 周淳 李宏伟 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第5期60-65,共6页
Compared with full device-independent quantum key distribution(DI-QKD), one-side device-independent QKD(1s DI-QKD) needs fewer requirements, which is much easier to meet. In this paper, by applying recently develo... Compared with full device-independent quantum key distribution(DI-QKD), one-side device-independent QKD(1s DI-QKD) needs fewer requirements, which is much easier to meet. In this paper, by applying recently developed novel time–energy entropic uncertainty relations, we present a time–energy high-dimensional one-side device-independent quantum key distribution(HD-QKD) and provide the security proof against coherent attacks. Besides, we connect the security with the quantum steering. By numerical simulation, we obtain the secret key rate for Alice's different detection efficiencies. The results show that our protocol can performance much better than the original 1s DI-QKD. Furthermore, we clarify the relation among the secret key rate, Alice's detection efficiency, and the dispersion coefficient. Finally, we simply analyze its performance in the optical fiber channel. 展开更多
关键词 secret coherent proof steering coincidence time Alice applying uncertainty entangled
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Interrogation of optical Ramsey spectrum and stability study of an ^(87)Sr optical lattice clock 被引量:1
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作者 Jing-Jing Xia Xiao-Tong Lu Hong Chang 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第3期306-310,共5页
The optical Ramsey spectrum is experimentally realized in an ^(87)Sr optical lattice clock, and the measured linewidth agrees well with theoretical expectation. The coherence time between the clock laser and the atoms... The optical Ramsey spectrum is experimentally realized in an ^(87)Sr optical lattice clock, and the measured linewidth agrees well with theoretical expectation. The coherence time between the clock laser and the atoms, which indicates the maximum free evolution period of using Ramsey detection to measure the atom-laser phase information, is determined as 340(23) ms by measuring the fringe contrasts of the Ramsey spectrum as a function of the free evolution period. Furthermore, with the same clock duty cycle of about 0.1, the clock stability is measured by using the Ramsey and Rabi spectra,respectively. The experimental and theoretical results show approximately the same stability as the two detection methods, which indicates that Ramsey detection cannot obviously improve the clock stability until the clock duty cycle is large enough. Thus, it is of great significance to choose the detection method of a specific clock. 展开更多
关键词 optical Ramsey spectrum optical lattice clock stability coherence time
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A novel timing synchronization for CO-OFDM systems using CAZAC sequences 被引量:3
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作者 李莉 姚望 +1 位作者 韩力 胡贵军 《Optoelectronics Letters》 EI 2017年第3期225-228,共4页
A novel symbol timing synchronization algorithm based on constant amplitude zero auto correlation(CAZAC) sequences is proposed for coherent optical orthogonal frequency division multiplexing(CO-OFDM) systems. The trai... A novel symbol timing synchronization algorithm based on constant amplitude zero auto correlation(CAZAC) sequences is proposed for coherent optical orthogonal frequency division multiplexing(CO-OFDM) systems. The training symbol of the proposed algorithm is comprised of four different parts, utilizing even symmetry property of each part to accomplish timing synchronization. The performance of the proposed algorithm is demonstrated by means of simulations in OFDM and CO-OFDM systems. The proposed algorithm is shown to eliminate the timing sidelobes of Park's algorithm and has a more accurate timing estimation. In the condition of chromatic dispersion(CD), the timing metric of the proposed method still maintains its peak value at the correct timing point, while the values are almost 0 at all the other positions. Meanwhile, the timing mean square error(MSE) of the proposed algorithm remains around 10^(-6). 展开更多
关键词 timing multiplexing utilizing eliminate accomplish symbol chromatic coherent symmetry plateau
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