Curtailed-Gaussian and Cosine Functions for Multihop Doppler Spectrum Modeling
Abstract: Wireless channels
are characterized among others by their Doppler spectrum. In the cooperative
diversity, one of diversity branch may consist of several mobile relays forming
multihop link which each hop introduced Doppler shift. With employing
amplify-and-forward (AF) relays, the Doppler shift keeps accumulating to the
end of the link. Doppler shift value affects the time varying channel rate,
which is a challenge in broadband mobile communication system. Hence, the
Doppler parameter is very important and must be considered in broadband mobile
communication system design and analysis. Unfortunately, it is hard to derive
the expressions of this Doppler spectrum in a closed form since a special
function under integration such as complete elliptic integral exists. To solve this problem, curve-fitting method
base on least-square is used. In this process, curtailed-Gaussian and cosine
functions are proposed as an approximation function. Then, from Kullback-Leiber
divergence test, it is showed that both proposed functions, i.e.,
curtailed-Gaussian and cosine functions have a good approximation as Doppler
spectrum modeling of Multihop mobile channel with all gain relays assumed as 1
and all mobile terminals are assumed move with almost same velocity.
Author: Titiek Suryani,
Gamantyo Hendrantoro
Kode Jurnal: jptkomputergg110013