A New Approach to Parameter Estimation
of Time-Varying Systems,
Applied to Fading Digital Mobile Radio Channels
Report UPTEC 90052R, May 1990.
Report In Postscript (no figures) (209K).
In Pdf (222K).
Parameters of time-varying dynamic systems may sometimes
be modelled as deterministic functions of time.
This is shown to be feasible, and to improve the estimation
accuracy, in the estimation of fading digital mobile radio channels.
Such systems may be described as finite impulse responses,
with coefficients varying, on a short time-scale, as
We propose to estimate the phase, amplitude and frequency of
these sinusoids, in each data burst in a TDMA system.
A prediction error identification algorithm has been developed,
assuming each data burst to begin with a known training sequence.
The parameter estimation is separated from the equalizer
design and the equalization phase.
The parameter estimation was tested on simulated data,
generated by a two ray channel model, with 10dB SNR.
The proposed algorithm provided very accurate channel models,
also in time intervals with severe fading.
In contrast, the alternative approach of using recursive
identification with a sliding data window was found not
to behave well.
- Related publications:
NUTEK 1991, which presented the results.
by L Lindbom, 1992, which develops the algorithm further.
Conference paper in IEEE
ICASSP'93 on using stochastic models of time-variations .
PhD Thesis by L Lindbom,
presenting an improved general design methodology.