channels_selective_fading_model2.block.yml

id: channels_selective_fading_model2
label: Frequency Selective Fading Model2

parameters:
-   id: N
    label: Num Sinusoids (Stochastic SoS model + delay drift)
    dtype: int
    default: '8'
-   id: fDTs
    label: Normalized Max Doppler (fD*Ts)
    dtype: real
    default: 0.2/samp_rate
-   id: LOS
    label: LOS Model
    dtype: enum
    options: ['False', 'True']
    option_labels: [Rayleigh/NLOS, Rician/LOS]
    option_attributes:
        hide_K: [all, '']
-   id: K
    label: Rician factor (K)
    dtype: real
    default: '4.0'
    hide: ${ LOS.hide_K }
-   id: seed
    label: Seed
    dtype: int
    default: '0'
-   id: delays
    label: PDP Delays (in samps)
    dtype: real_vector
    default: (1.0,1.9,2.7)
-   id: delay_std
    label: PDP Delay StdDev (per samp)
    dtype: real_vector
    default: (1e-4,1e-4,1e-4)
-   id: delay_maxdev
    label: PDP Delay Max-Dev (per samp)
    dtype: real_vector
    default: (0.5,0.7,0.9)
-   id: mags
    label: PDP Magnitudes
    dtype: real_vector
    default: (1,0.95,0.8)
-   id: ntaps
    label: Num Taps
    dtype: int
    default: '8'

inputs:
-   domain: stream
    dtype: complex

outputs:
-   domain: stream
    dtype: complex
-   domain: message
    id: taps
    optional: true

templates:
    imports: from gnuradio import channels
    make: channels.selective_fading_model2( ${N}, ${fDTs}, ${LOS}, ${K}, ${seed},
        ${delays}, ${delay_std}, ${delay_maxdev}, ${mags}, ${ntaps} )
    callbacks:
    - set_fDTs(${fDTs})
    - set_K(${K})

documentation: |-
    int d_N=8;          // number of sinusoids used to simulate gain on each ray
        float d_fDTs=0.01   // normalized maximum doppler frequency (f_doppler / f_samprate)
        float d_K=4;        // Rician factor (ratio of the specular power to the scattered power)
        bool d_LOS=true;    // LOS path exists? chooses Rician (LOS) vs Rayleigh (NLOS) model.
        int seed=0;         // noise seed
        int ntaps;          // Number of FIR taps to use in selective fading model

          These two vectors comprise the Power Delay Profile of the signal
        float_vector delays   // Time delay in the fir filter (in samples) for each arriving WSSUS Ray
        float_vector mags     // Magnitude corresponding to each WSSUS Ray

        If using a LOS model, the first delay and mag should correspond with the LOS component

      References:

      The flat-fading portion of the algorithm implements the following
       Compact Rayleigh and Rician fading simulator based on random walk processes
       A. Alimohammad S.F. Fard B.F. Cockburn C. Schlegel
       26th November 2008
        (Algorithm III)
        ( with a novel addition of time delay tap random walk )

      The frequency selective extension of the block roughly implements
       A Low-Complexity Hardware Implementation of Discrete-Time
       Frequency-Selective Rayleigh Fading Channels
       F. Ren and Y. Zheng
       24-27 May 2009

      Implementation by Tim O'Shea

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