scholarly journals Differential OFDM Employing AFC for Doubly-Selective Channels in the Presence of Time-Varying Doppler Shifts

2021 ◽  
Vol 25 (5) ◽  
pp. 175-185
Author(s):  
Yui Nakai ◽  
Yuka Tanaka ◽  
Hiroshi Kubo
Keyword(s):  
Time Varying ◽  
Doubly Selective Channels ◽  
Doppler Shifts

scholarly journals The Fast Simulation of Scattering Characteristics from a Simplified Time Varying Sea Surface

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Yiwen Wei ◽  
Lixin Guo ◽  
Xiao Meng
Keyword(s):  
Realistic Model ◽  
Short Wave ◽  
Capillary Waves ◽  
Long Waves ◽  
Sea Surface ◽  
Surface Model ◽  
Time Varying ◽  
Resonant Condition ◽  
Scattering Coefficients ◽  
Doppler Shifts

This paper aims at applying a simplified sea surface model into the physical optics (PO) method to accelerate the scattering calculation from 1D time varying sea surface. To reduce the number of the segments and make further improvement on the efficiency of PO method, a simplified sea surface is proposed. In this simplified sea surface, the geometry of long waves is locally approximated by tilted facets that are much longer than the electromagnetic wavelength. The capillary waves are considered to be sinusoidal line superimposing on the long waves. The wavenumber of the sinusoidal waves is supposed to satisfy the resonant condition of Bragg waves which is dominant in all the scattered short wave components. Since the capillary wave is periodical within one facet, an analytical integration of the PO term can be performed. The backscattering coefficient obtained from a simplified sea surface model agrees well with that obtained from a realistic sea surface. The Doppler shifts and width also agree well with the realistic model since the capillary waves are taken into consideration. The good agreements indicate that the simplified model is reasonable and valid in predicting both the scattering coefficients and the Doppler spectra.

Time-varying FIR equalization for doubly selective channels

2005 ◽  
Vol 4 (1) ◽  
pp. 202-214 ◽  
Author(s):  
I. Barhumi ◽  
G. Leus ◽  
M. Moonen
Keyword(s):  
Time Varying ◽  
Doubly Selective Channels
Sign in / Sign up

Export Citation Format

Share Document