We propose a competitive approach for analysis and optimization of optical fiber performance. Taking into account the standard fiber fabrication cycle, we develop a model of highly multistepped optical fiber. We intro...
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We propose a competitive approach for analysis and optimization of optical fiber performance. Taking into account the standard fiber fabrication cycle, we develop a model of highly multistepped optical fiber. We introduce a fast and accurate algorithm which allows one to obtain propagation constants and transverse fields for systems with thousands of steps within seconds. The approach relies on both the exact analytical formulation of the corresponding eigenvalue problem and an original solving algorithm of linear complexity with respect to the number of steps. The model accurately represents arbitrary smooth profiles with azimuthal symmetry, which, together with low computation time, opens up ample opportunities for various optimization schemes. Obtained results are compared with those of other numerical and analytical methods.
In this note, we describe a reduced-complexity solution to the nonlinear H-infinity control problem. This reduction applies to systems where some of the states are perfectly known, and is an intermediate problem betwe...
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In this note, we describe a reduced-complexity solution to the nonlinear H-infinity control problem. This reduction applies to systems where some of the states are perfectly known, and is an intermediate problem between full state feedback and the standard measurement feedback problem. The reduction of computational complexity is significant and of practical importance. Online implementation is feasible with 2003 computer technology for a range of practical engineering design problems.
For reduction of computational complexity in the 1A algorithm, the thinned-out 1A algorithm in which only one step size is updated every iteration is proposed and is complementarily switched with the HA algorithm acco...
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For reduction of computational complexity in the 1A algorithm, the thinned-out 1A algorithm in which only one step size is updated every iteration is proposed and is complementarily switched with the HA algorithm according to the convergence. The switching is determined by using the gradient of the error signal power. These are investigated through the computer simulations.
This paper discusses the channel estimation algorithm in the adaptive maximum likelihood sequence estimation (MLSE) and proposes the variable-gain least square (VLMS) algorithm that can realize a fast acquisition by a...
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This paper discusses the channel estimation algorithm in the adaptive maximum likelihood sequence estimation (MLSE) and proposes the variable-gain least square (VLMS) algorithm that can realize a fast acquisition by a simple configuration. When the sent code is a random sequence, VLMS is represented by a deterministic canonical equation based on the fact that a deterministic autocorrelation matrix for VLMS can be diagonalized. It is shown that VLMS can be realized with nearly the same computationalcomplexity as least-mean square (LMS) algorithm. It is shown theoretically by analysis that VLMS can realize the same fast acquisition and tracking characteristics as those of the recursive least square (RLS) algorithm. An algorithm also is derived which is an extension of the basic idea of VLMS and can be used for the fractional MLSE equalizer. It is shown experimentally that the fractional MLSE equalizer with VLSE algorithm can compensate the performance deterioration due to the sampling phase error. In the two-wave Rayleigh fading environment with f(d)T = 4.0 x 10(-4), the floor error can be suppressed below 10(-4). It is shown also experimentally that the proposed equalizer has an excellent synchronization performance in which the initial acquisition can be completed in approximately six symbols.
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