Hi,
From the introduction of the ITU models, I find the spectrum for each tap is specified, e.g. classic, flat. Are there any specification on the distribution for each tap? In other words, the distribution of each tap is required to be Gaussian or Gaussian plus LOS for In-phase/Quadrature components? Thanks,
Pengda
Interesting question. Referring to the the recommendation here: http://www.itu.int/dms_pubrec/itu-r/rec/m/R-REC-M.1225-0-199702-I!!PDF-E.pdf , I assume you are talking about table 4 etc, which do not specify the fading type. However, paragraph 1.1.1 states: "Fading ranges from Rician to Rayleigh....", for indoor models. Paragraph 1.1.2 and 1.1.3 have similar guidelines for outdoor and vehicular environments.
My interpretation is that you should try to judge whether the environment you are modelling has a strong (line-of-sight) component or not, and choose the Rician or Gaussian distribution accordingly.
You can also find an interesting overview of other channel models here: http://www.cse.wustl.edu/~jain/cse574-08/ftp/channel_model_tutorial.pdf
Hope this helps.
In case that you would have a one dominant line of sight only the first tap ( least delay ) should be considered and the other taps are still Gaussian (central limit theory).
The multipath fading is modeled as a tapped-delay line with 6 taps with non-uniform delays. The gain associated with each tap is characterized by a distribution (Ricean with a K-factor>0, or Rayleigh with K-factor=0) and the maximum Doppler frequency. For each tap, the method of filtered noise is used to generate channel coefficients with the specified distribution and spectral power density.
Thank you for your responses. I am bright on this question.
@Gert Cuypers
It seems that there is an presumption-only Rician or Gaussian distributions are the model for describing the statistical feature of the each channel tap. I am wondering whether some other distributions, like Suzuki, Nakagami, Weibull, can also be applied to the channel taps?
@Keivan Bahmani
LOS component determines the channel type is Rayleigh or Rician. Besides the two, how about the other channel types?
@Aamir Habib
I can understand how to emulate/simulate the fading channels. My question is whether ITU channel models consider not only Rician/Rayleigh, but also the other distributions?
- Badges
- Science topic