# Frequency Selective Fading Model2

From GNU Radio

This block implements a basic fading model simulator that can be used to help evaluate, design, and test various signals, waveforms, and algorithms.

- 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

## Parameters

(*R*): *Run-time adjustable*

- Num Sinusoids (Stochastic SoS model + delay drift)
- Number of sinusoids used to simulate gain on each ray

- Normalized Max Doppler (fD*Ts) (
*R*) - Normalized maximum doppler frequency (f_doppler / f_samprate)

- LOS Model
- LOS path exists? chooses Rician (LOS) vs Rayleigh (NLOS) model.

- Rician factor (K) (
*R*) - Rician factor (ratio of the specular power to the scattered power)

- Seed
- Noise seed

- PDP Delays (samp)
- Time delay in the fir filter (in samples) for each arriving WSSUS Ray

- PDP Delay StdDev (per samp)
- A vector of values that specify the gaussian step size std of delays

- PDP Delay Max-Dev (per samp)
- A vector of values that specify the max deviation of each delay component

- PDP Magnitudes
- Magnitude corresponding to each WSSUS Ray

- Num Taps
- Number of FIR taps to use in selective fading model

## Example Flowgraph

Insert description of flowgraph here, then show a screenshot of the flowgraph and the output if there is an interesting GUI. Currently we have no standard method of uploading the actual flowgraph to the wiki or git repo, unfortunately. The plan is to have an example flowgraph showing how the block might be used, for every block, and the flowgraphs will live in the git repo.

## Source Files

- C++ files
- [1]

- Header files
- [2]

- Public header files
- [3]

- Block definition
- [4]