edu.cmu.emulator.signal
Class GeoFadingSpectrum

java.lang.Object
  edu.cmu.emulator.signal.GeoFadingSpectrum

public class GeoFadingSpectrum
extends Object

Generate Doppler power spectrum Model: Geometrical Model for V2V - Cheng Assumptions: - Model road-side obstacles only - Similar (no) delay for all reflected path

Field Summary

protected double	d_s Roadside scatterers distance
protected double	d0 Reference distance
protected double	dc Two-ray cross-over distance d_c
protected double	density
protected double	dtr Tx-Rx distance
static double	fcarrier_GHz Carrier Frequency
protected double	fm Maximum Doppler frequency
protected double[][]	fSpec Doppler Spectrum
protected double[][]	fSpecI Interpolated doppler spectrum at given freq points
protected Logger	log
protected int	N Frequency Samples
protected Antenna	receiver Receiver
protected double[][]	rho Roadside Object Density
protected Antenna	transmitter Trasmitter
protected double	V_min Minimum Speed
protected double	V_rx Rx speed
protected double	V_tx Tx speed

Constructor Summary

GeoFadingSpectrum(Antenna srcAntenna, Antenna destAntenna)
Constructor.

GeoFadingSpectrum(String specName, int samples)
Constructor for manual use.

Method Summary

protected double[]	gen_Sf(double theta) Calculate frequency shift, response and power density at given angle
void	genDopperSpectrum(double R_tx, double d_tr, double rho) Generate Doppler Spectrum using speed Ratio and default MAX_SPEED
void	genDopplerSpectrum() Generate Doppler Spectrum using default parameters
void	genDopplerSpectrum(double v_tx, double v_rx, double d_tr, double rho) Generate Doppler Spectrum for given set of parameters
protected double	get_density(double theta) Calculate scatterer density at angle theta
double	getDMDistance(double d) Calculate the dual-mode distance
protected double[][]	getFadingSpectrum() Get (frequency shift) Interpolated Doppler Spectrum
protected double[][]	getFadingSpectrumOriginal() Get Original Doppler Spectrum/Power Density
protected double	interp_lin(double f1, double f2, double Sf1, double Sf2, double f) Estimate power density at given frequency shift f Mathod 1: linear interpolation
protected double[]	interp_poly(double[] f0, double[] Sf0, double[] f, int power) Estimate power density at given frequency shift f points Method 2: Spline interpolation
protected void	interpolateSpectrum() Interpolate Spectrum at desired frequency shift points
static void	main(String[] args)
protected void	show(String name, double value) for debug: check parameter values

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

transmitter

protected Antenna transmitter

Trasmitter

receiver

protected Antenna receiver

Receiver

V_tx

protected double V_tx

Tx speed

V_rx

protected double V_rx

Rx speed

V_min

protected double V_min

Minimum Speed

dtr

protected double dtr

Tx-Rx distance

fm

protected double fm

Maximum Doppler frequency

N

protected int N

Frequency Samples

rho

protected double[][] rho

Roadside Object Density

density

protected double density

fcarrier_GHz

public static final double fcarrier_GHz

Carrier Frequency

See Also:

Constant Field Values

d0

protected double d0

Reference distance

dc

protected double dc

Two-ray cross-over distance d_c

d_s

protected double d_s

Roadside scatterers distance

fSpec

protected double[][] fSpec

Doppler Spectrum

fSpecI

protected double[][] fSpecI

Interpolated doppler spectrum at given freq points

log

protected Logger log

Constructor Detail

GeoFadingSpectrum

public GeoFadingSpectrum(Antenna srcAntenna,
                         Antenna destAntenna)

Constructor.

GeoFadingSpectrum

public GeoFadingSpectrum(String specName,
                         int samples)

Constructor for manual use.

Method Detail

genDopplerSpectrum

public void genDopplerSpectrum()

Generate Doppler Spectrum using default parameters

genDopperSpectrum

public void genDopperSpectrum(double R_tx,
                              double d_tr,
                              double rho)

Generate Doppler Spectrum using speed Ratio and default MAX_SPEED

genDopplerSpectrum

public void genDopplerSpectrum(double v_tx,
                               double v_rx,
                               double d_tr,
                               double rho)

Generate Doppler Spectrum for given set of parameters

show

protected void show(String name,
                    double value)

for debug: check parameter values

gen_Sf

protected double[] gen_Sf(double theta)

Calculate frequency shift, response and power density at given angle

Parameters:

theta - scatterer at angle theta with respect to receiver

Returns:

Sf[] Sf[0] : power density Sf at shift f Sf[1] : frequency shift f at this angle Sf[2] : response observed at this angle Sf[3] : probablility distribution p at this angle

get_density

protected double get_density(double theta)

Calculate scatterer density at angle theta

Parameters:

theta - angle with respect to receiver

Returns:

density, between [0,1]

getDMDistance

public double getDMDistance(double d)

Calculate the dual-mode distance

Parameters:

d - original distance

Returns:

dual-model distance D(d)

interpolateSpectrum

protected void interpolateSpectrum()

Interpolate Spectrum at desired frequency shift points

interp_lin

protected double interp_lin(double f1,
                            double f2,
                            double Sf1,
                            double Sf2,
                            double f)

Estimate power density at given frequency shift f Mathod 1: linear interpolation

Parameters:

f1 - frequency shift f1

f2 - frequency shift f2

Sf1 - power density Sf1

Sf1 - power density Sf2

f - given frequency shift f

interp_poly

protected double[] interp_poly(double[] f0,
                               double[] Sf0,
                               double[] f,
                               int power)

Estimate power density at given frequency shift f points Method 2: Spline interpolation

Parameters:

f0 - array of frequency shift f0

Sf0 - array of power density Sf0. the length should match with f0

f - array of desired shift pings f

power - polynomial order. In general 3 (cubic) gives the best trade-off

Returns:

power density at given frequency point f

getFadingSpectrumOriginal

protected double[][] getFadingSpectrumOriginal()

Get Original Doppler Spectrum/Power Density

Returns:

1-step Doppler Spectrum where frequency points are not equally spaced.

getFadingSpectrum

protected double[][] getFadingSpectrum()

Get (frequency shift) Interpolated Doppler Spectrum

Returns:

Normalized Doppler Spectrum where frequency points are evenly spaced.

main

public static void main(String[] args)