Types of fading

Viewing 4 posts - 1 through 4 (of 4 total)
  • Author
    Posts
  • #8287
    Darren
    Participant

    Dear community,

    Could you please help me telling me what is the difference between macroscopic fading and shadow fading? As far as I knew, they’re similar and both are caused by shadowing effects of buildings and other big obstructions, so I was wondering why you made a distinction between them.

    Thank you,
    Darren

    #8289
    Sherif
    Participant

    Hi Darren,

    In the implementation, macroscopic fading refers to signal attenuation based on BS-UE separation distance (i.e., pathloss) while shadow fading models the deviations from the average pathloss values due to structural/environmental features such as terrain, buildings and obstacles, as you rightly said. Both are distance-dependent with pathloss modeled using the usual pathloss equation and shadow fading modeled as a log-normal distribution with zero mean and frequency-dependent standard deviation value. A combination of both is sometimes referred to as effective pathloss.

    In terms of terminology, however, the combination of pathloss, shadow fading, antenna gain and minimum coupling loss is referred to as MACROSCALE FADING, distinguishing it from the time-varying SMALL-SCALE/MICROSACLE/FAST FADING.

    I hope this clarifies the distinction between them. Just a try, the developers will provide further clarification if need be!

    The Doctoral Dissertation in the link should also provide further guide.
    https://publik.tuwien.ac.at/files/PubDat_226618.pdf

    Best regards,

    Sherif

    #8296
    Darren
    Participant

    Dear Sherif,

    Thank you so much for your response! I have one more question, though, I hope you can help me with that as well. Do you happen to know whether the simulator considers both flat and/or linear attenuations? I’ve been going through the codes, but can’t find anything. If flat/linear attenuations have been considered, I need to know their corresponding values.

    I appreciate your time.

    Best regards,
    Darren

    #8397

    Dear Darren,

    In Vienna LTE-A System Level Simulator, large scale fading effects (macroscopic path-loss and shadow fading) are denoted by specific models, e.g., for distance dependent path-loss you can find several models under +macroscopic_pathloss_models such as the ones described in 3GPP TR 36.873, TR 25.814, etc.; for modeling shadow fading, a so called ‘claussen’ method is implemented. This method is set with the following command: LTE_config.shadow_fading_type = ‘claussen’, and creates a correlated map of the shadow fading based on the given standard deviation.

    More details about ‘claussen’ method is given in the original paper of H. Claussen “Efficient modeling of channel maps with correlated shadow fading in mobile radio systems”.

    Best regards,
    Fjolla

Viewing 4 posts - 1 through 4 (of 4 total)
  • You must be logged in to reply to this topic.