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Carrier Synchronization for Very Low SNR
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作者 Jun-Hui Xu Zhao Wang Zhong-Jie Gao Zhong-Pei Zhang 《Journal of Electronic Science and Technology》 CAS 2010年第2期103-107,共5页
The Turbo decoding performance will suffer serious degradation under low signal-to-noise ratios (SNR) conditions for the reason of residual frequency and phase offset in the carrier. In this paper, an improved resid... The Turbo decoding performance will suffer serious degradation under low signal-to-noise ratios (SNR) conditions for the reason of residual frequency and phase offset in the carrier. In this paper, an improved residual carrier frequency offset estimation algorithm based on a priori probability aided (APPA) phase estimation is proposed. A carrier synchronization loop that combines the iterative turbo decoder and the phase estimator together is constructed, where the extrinsic information obtained from the Turbo decoder is used to aid an iterative phase estimation process. The simulation results show that the algorithm performs successfully under very low SNR conditions (for example, less than -7.4 dB) with large frequency offset and phase error and the performance of this algorithm is very close to the optimally synchronized system. 展开更多
关键词 Index Terms- Carrier synchronization frequency offset phase error signal-to-noise ratios (snr).
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Optimizing Optical Attocells Positioning of Indoor Visible Light Communication System
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作者 Mohammed S.M.Gismalla Asrul I.Azmi +5 位作者 Mohd R.Salim Farabi Iqbal Mohammad F.L.Abdullah Mosab Hamdan Muzaffar Hamzah Abu Sahmah M.Supa’at 《Computers, Materials & Continua》 SCIE EI 2023年第2期3607-3625,共19页
Visible light communication(VLC),which is a prominent emerging solution that complements the radio frequency(RF)technology,exhibits the potential to meet the demands of fifth-generation(5G)and beyond technologies.The ... Visible light communication(VLC),which is a prominent emerging solution that complements the radio frequency(RF)technology,exhibits the potential to meet the demands of fifth-generation(5G)and beyond technologies.The random movement of mobile terminals in the indoor environment is a challenge in the VLC system.The model of optical attocells has a critical role in the uniform distribution and the quality of communication links in terms of received power and signal-to-noise ratio(SNR).As such,the optical attocells positions were optimized in this study with a developed try and error(TE)algorithm.The optimized optical attocells were examined and compared with previous models.This novel approach had successfully increased minimum received power from−1.29 to−0.225 dBm,along with enhanced SNR performance by 2.06 dB.The bit error rate(BER)was reduced to 4.42×10−8 and 6.63×10−14 by utilizing OOK-NRZ and BPSK modulation techniques,respectively.The optimized attocells positions displayed better uniform distribution,as both received power and SNR performances improved by 0.45 and 0.026,respectively.As the results of the proposed model are optimal,it is suitable for standard office and room model applications. 展开更多
关键词 Visible light communication(VLC) optical attocell received power signal-to-noise ratio(snr) bit error rate(BER) coefficient of variation(CV)
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Target tracking methods based on a signal-to-noise ratio model 被引量:2
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作者 Dai LIU Yong-bo ZHAO +2 位作者 Zi-qiao YUAN Jie-tao LI Guo-ji CHEN 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2020年第12期1804-1814,共11页
In traditional target tracking methods,the angle error and range error are often measured by the empirical value,while observation noise is a constant.In this paper,the angle error and range error are analyzed.They ar... In traditional target tracking methods,the angle error and range error are often measured by the empirical value,while observation noise is a constant.In this paper,the angle error and range error are analyzed.They are influenced by the signalto-noise ratio(SNR).Therefore,a model related to SNR has been established,in which the SNR information is applied for target tracking.Combined with an advanced nonlinear filter method,the extended Kalman filter method based on the SNR model(SNR-EKF)and the unscented Kalman filter method based on the SNR model(SNR-UKF)are proposed.There is little difference between the SNR-EKF and SNR-UKF methods in position precision,but the SNR-EKF method has advantages in computation time and the SNR-UKF method has advantages in velocity precision.Simulation results show that target tracking methods based on the SNR model can greatly improve the tracking performance compared with traditional tracking methods.The target tracking accuracy and convergence speed of the proposed methods have significant improvements. 展开更多
关键词 signal-to-noise ratio(snr)model Target tracking Angle error Range error Nonlinear filter
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Hardware implementation of adaptive filter for noise cancellation using TMS320C6713
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作者 Swati S Godbole Sanjay B Pokle 《Journal of Measurement Science and Instrumentation》 CAS 2014年第3期38-47,共10页
Daily, we experience the effects of audio noise, which contaminates the original information bearing signal with noise from its surrounding environment. This paper focuses on real-time hardware implementation of multi... Daily, we experience the effects of audio noise, which contaminates the original information bearing signal with noise from its surrounding environment. This paper focuses on real-time hardware implementation of multi-tap adaptive noise cancellation (ANC) system by using the least mean square (LMS) algorithm on TMS320C6713 to remove undesired noise from a received signal for various audio related applications. Three different experiments are carried out by considering different audio inputs to test the efficiency of the designed ANC system. The 'C' code implementation of LMS algorithm is introduced and simulated in code composer studio (CCS), then realized on the digital signal processor (DSP) C6713. The 300 Hz, 500 Hz, 800 Hz, 1 kHz and 3 kHz of tone signals and male speech signal are used as the reference inputs to trace the noise of signal until it is eliminated. The performance of ANC system is studied in terms of convergence speed, order of the filter and signal-to-noise ratio (SNR). The experimentam results demonstrate that the designed system shows a consider- able improvement in SNR. 展开更多
关键词 adaptive noise cancellation (ANC) digital signal processor (DSP) mean square error (MSE) least mean squarealgorithm (LMS) TMS320C6713 DSK code composer studio (CCS) signal-to-noise ratio (snr
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带前置光放大的星间微波光子链路性能优化 被引量:4
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作者 朱子行 赵尚弘 +4 位作者 李勇军 楚兴春 张辉 王翔 赵顾颢 《光电子.激光》 EI CAS CSCD 北大核心 2013年第3期500-507,共8页
考虑发射机和接收机对准误差引起的信号衰落,推导出带前置光放大的星间微波光子链路输出信噪比(SNR)的解析表达式,并建立了基于平均SNR原则的链路优化模型。在给定SNR要求及对准误差条件下,对Mach-Zehnder调制器(MZM)直流偏置相移进行... 考虑发射机和接收机对准误差引起的信号衰落,推导出带前置光放大的星间微波光子链路输出信噪比(SNR)的解析表达式,并建立了基于平均SNR原则的链路优化模型。在给定SNR要求及对准误差条件下,对Mach-Zehnder调制器(MZM)直流偏置相移进行了优化,使所需激光器(LD)输出功率最小,并进一步分析了前置放大器参数对最小LD输出功率和最优直流偏置相移的影响。数值仿真结果表明,与增益相比,前置放大器噪声系数决定了指定SNR所需的最小LD输出功率。当对准误差角标准差为0.4μrad时,噪声系数加倍会使SNR达到15.56dB时所需的最小LD输出功率增加6.73dB。然而,前置放大器噪声系数对最优的直流偏置相移几乎无影响,噪声系数加倍后最优直流偏置相移的变化不会超过0.003π。 展开更多
关键词 星间微波光子链路 前置光放大器 信噪比(snr) 对准误差
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