In this paper, we investigate the channel estimation problem for ambient backscatter communication system where the backscatter device utilizes large intelligent surface (LIS). For the considered LIS-assisted system, ...
详细信息
ISBN:
(纸本)9781728135557
In this paper, we investigate the channel estimation problem for ambient backscatter communication system where the backscatter device utilizes large intelligent surface (LIS). For the considered LIS-assisted system, a general system model for ambient backscatter with LIS features is presented. Based on the general mathematical framework we proposed, we design an estimator consisting of initial estimation and subsequent iteration to acquire the channel parameters. To further evaluate the performance of the suggested estimator, we derive the corresponding Cramer-Rao lower bounds (CRLBs) for channel estimates. Simulation results are then provided to corroborate the proposed studies.
We investigate the optimal carrier sensing threshold in random CSMA/CA networks considering the effect of binary exponential backoff. We propose an iterative algorithm for optimizing the carrier sensing threshold and ...
详细信息
We investigate the optimal carrier sensing threshold in random CSMA/CA networks considering the effect of binary exponential backoff. We propose an iterative algorithm for optimizing the carrier sensing threshold and hence maximizing the area spectral efficiency. We verify that simulations are consistent with our analytical results.
Design of infinite impulse response (IIR) digital filters to approximate some desired magnitude-frequency response is a classical research topic in signal processing. When a pole radius constraint is imposed, however,...
详细信息
ISBN:
(纸本)9781479981311
Design of infinite impulse response (IIR) digital filters to approximate some desired magnitude-frequency response is a classical research topic in signal processing. When a pole radius constraint is imposed, however, the problem becomes challenging and few solution methods are available. This paper converts the magnitude-response approximation problem into another problem that approximates the desired magnitude response and an accompanied phase response simultaneously. By iteratively updating the accompanied phase response. a solution to the original magnitude-response approximation problem can be obtained. A striking feature of the proposed method is that the pole radius constraint can be easily incorporated in the problem. Simulations and comparisons demonstrate the effectiveness of the method.
With the increasing demand for electricity, accurate prediction of power load is of great significance for improving the quality of power grid planning and construction. Traditional saturated load forecasting method i...
详细信息
ISBN:
(纸本)9781450372930
With the increasing demand for electricity, accurate prediction of power load is of great significance for improving the quality of power grid planning and construction. Traditional saturated load forecasting method is greatly affected by historical information. This paper proposed an improved spatial load forecasting(SLF) method based on error model transformation. Considering the nature and development time of urban land, each district is divided into different blocks, the blocks are classified into two categories: homogeneous blocks and simultaneous blocks. An iterative load forecasting system architecture is proposed, which transforms blocks load forecasting problem into two sub-problems: multi-level gridding parameter training and model integrative prediction. Land utility and historical data are both investigated during the load forecasting procedure. Simulation result indicates that accuracy of calculated prediction result is higher and less affected by the noise.
We propose a gradient based iterative algorithm with multiple iterative factors(MGI) to find the solutions of the Sylvester discrete-time periodic matrix equations Aj Xj + Xj+1 Bj = Cj(j = 1, 2, ···, T)...
详细信息
We propose a gradient based iterative algorithm with multiple iterative factors(MGI) to find the solutions of the Sylvester discrete-time periodic matrix equations Aj Xj + Xj+1 Bj = Cj(j = 1, 2, ···, T). It is proved that the exact solution of the periodic matrix equations can be converged by the MGI method for any initial matrices. Then, we study the optimal convergence rate of gradient based iterative algorithm with single iterative factor(SGI). Nextly, we compare the convergence rate of the two algorithms, and find that MGI is faster than SGI when the appropriate convergence factors μj are selected. Finally, a numerical example is given to verify that MGI is superior to SGI in both speed and iterative steps.
In this paper, a new system of generalized mixed implicity equilibrium problems involving non-monotone set-valued mappings is introduced and studied in real reflexive Banach spaces. Following the idea of Moudafi, we c...
详细信息
In this paper, a new system of generalized mixed implicity equilibrium problems involving non-monotone set-valued mappings is introduced and studied in real reflexive Banach spaces. Following the idea of Moudafi, we consider a system of generalized equations problems and show its equivalence with the system of generalized mixed implicity equilibrium problems. By using a fixed point formulation of the system of generalized equation problems, a new iterative algorithm for solving the system of generalized mixed implicity equilibrium problems is suggested and analyzed. The strong convergence of the iterative sequences generated by the algorithm is proved under suitable conditions. These results are new and unify and generalize some recent results in this field. (C) 2011 Elsevier Inc. All rights reserved.
The sensitivity of phase-shifting interferometers (PSIs) to vibration impairs their application in unsteady environment. iterative algorithms were developed to desensitise the effect of vibration on PSIs, but their de...
详细信息
The sensitivity of phase-shifting interferometers (PSIs) to vibration impairs their application in unsteady environment. iterative algorithms were developed to desensitise the effect of vibration on PSIs, but their desensitising capability is restricted by the estimated initial value. In this paper, a spatial carrier-assisted method is proposed, in which a wavefront phase retrieved from an additional spatial-carrier interferogram is used as the initial value. Because of the benefits of spatial carrier, vibration immunity and sign determination, iteration could converge to accurate value even when interferometers are under severe vibration. To reduce the possibility of transverse movement of the measured surface, subsampling strategy is further proposed to decrease the required tilt angle, with the additional benefit of decreasing the calculation time of iteration. Computer simulations and experiments are performed to verify the effectiveness of the proposed method. Results indicate that the vibration desensitising capability of an iterative algorithm is significantly enhanced by the proposed method. The proposed method improves the vibration desensitising capability with low cost and is thus highly compatible. (C) 2017 Elsevier Ltd. All rights reserved.
In this paper, we introduce parallel and cyclic iterative algorithms for solving the multiple-set split equality common fixed-point problem of demicontractive operators. We propose a way of selecting the stepsizes suc...
详细信息
In this paper, we introduce parallel and cyclic iterative algorithms for solving the multiple-set split equality common fixed-point problem of demicontractive operators. We propose a way of selecting the stepsizes such that the implementation of our algorithms does not need any prior information about operator norms. It thus avoids the difficult task of estimating the operator norms. We also combine the process of cyclic and parallel together and propose two mixed iterative algorithms without prior knowledge of operator norms. The weak convergence theorems of the proposed algorithms are established under some suitable control conditions in a real Hilbert space. Some numerical experiments are given for the proposed iterative algorithms.
A problem of studying parametric oscillations with damping is reduced to a spectral problem for a linear bundle of operators in a Hilbert space. This spectral problem is solved by an efficient algorithm. The boundarie...
详细信息
A problem of studying parametric oscillations with damping is reduced to a spectral problem for a linear bundle of operators in a Hilbert space. This spectral problem is solved by an efficient algorithm. The boundaries of the first stability domain for different values of a damping factor and a special form of a periodic function in the equation are calculated.
In this paper, an efficient thermal analysis method is presented for large scale compound semiconductor integrated circuits based on a heterojunction bipolar transistor with considering the change of thermal conductiv...
详细信息
In this paper, an efficient thermal analysis method is presented for large scale compound semiconductor integrated circuits based on a heterojunction bipolar transistor with considering the change of thermal conductivity with *** influence caused by the thermal conductivity can be equivalent to the increment of the local temperature surrounding the individual device. The junction temperature for each device can be efficiently calculated by the combination of the semianalytic temperature distribution function and the iteration of local temperature with high accuracy, providing a temperature distribution for a full chip. Applying this method to the InP frequency divider chip and the GaAs analog to digital converter chip, the computational results well agree with the results from the simulator COMSOL and the infrared thermal imager respectively. The proposed method can also be applied to thermal analysis in various kinds of semiconductor integrated circuits.
暂无评论