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Zhang H.,Nanjing University of Aeronautics and Astronautics | Song X.,Nanjing University of Aeronautics and Astronautics | Zhu Y.,The 63rd Research Institute of the General Staff Headquarters | Tu S.,Nanjing University of Aeronautics and Astronautics
Shuju Caiji Yu Chuli/Journal of Data Acquisition and Processing | Year: 2015

The signal sparsity is often unknown, or even changed with time in spectrum sensing. Therefore, a variable step-size sequential compressed detection algorithm is proposed by combining the adaptive theory with the sequential compressed spectrum sensing technology. The functional relationship is established between step-size factor of the next needed measurement numbers and current distance from the likelihood ratio and the detection thresholds. In addition, the shortcoming of the fixed step size of the measurement increment in the existing sequential compressed sensing is overcomed in the proposed algorithm. Theoretical analysis and computer simulations are conducted by introducing the rules of step size adjustment with piecewise function and parabolic function, respectively. Simulations prove that, the proposed algorithm has the faster detection speed, less measurements number and lower computational complexities, compared with the existing sequential compressed detection scheme. ©, 2015, Journal of Data Acquisition and Processing. All right reserved. Source


Zhu Y.-G.,PLA University of Science and Technology | Yao F.-Q.,The 63rd Research Institute of the General Staff Headquarters | Xu J.-Y.,The 63rd Research Institute of the General Staff Headquarters | Liu Y.-X.,The 63rd Research Institute of the General Staff Headquarters | Zhu Y.-Y.,PLA Commanding Communications Academy
Jiefangjun Ligong Daxue Xuebao/Journal of PLA University of Science and Technology (Natural Science Edition) | Year: 2010

The convergence rate of the NLMS adaptive equalizer is affected seriously in the presence of strong narrowband interference. To solve this problem, based on the higher order Butterweck solution, the convergence performance of the NLMS adaptive equalizer was analyzed in the presence of narrowband interference. The analytical expression of convergence time was proposed for the ideal channel, while the effects of the equalizer length, ri, s, multipath factor and interference frequency were analyzed for the multipath channel. The results of theoretical analysis and simulation show that the convergence time of the NLMS adaptive equalizer in the ideal channel is proportional to the length of the equalizer while the ri, s, is independent of the interference frequency and that over the multipath channel, the convergence time is in proportional to ri, s, but has a non-linear relationship with the equalizer length, the multipath characteristics and the interference frequency. Source

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