Filter input signal through SISO multipath fading channel
Communications Toolbox / Channels
The SISO Fading Channel block filters an input signal using a singleinput/singleoutput (SISO) multipath fading channel. This block models both Rayleigh and Rician fading. For processing details, see the Algorithms section.
in
— Input data signalInput data signal, specified as an N_{S}by1 vector. N_{S} represents the number of samples in the input signal.
Data Types: double
 single
Complex Number Support: Yes
Out1
— Output data signal for fading channelOutput data signal for the fading channel, returned as an N_{S}by1 vector. N_{S} represents the number of samples in the input signal.
Gain
— Discrete path gainsDiscrete path gains of the underlying fading process, returned as an N_{S}byN_{P} matrix.
N_{S} represents the number of samples in the input signal.
N_{P} represents the number of channel paths.
To enable this port, on the Main tab, select Output channel path gains.
Delay
— Channel filter delayChannel filter delay, returned as a scalar.
To enable this port, on the Main tab, select Output channel filter delay.
Inherit sample rate from input
— Option to inherit the sample rate from inputSelect this parameter to use the sample rate of the input signal when processing. When
Inherit sample rate from input
is selected, the sample rate is
N_{S}/T_{S},
where N_{S} is the number of input samples, and
T_{S} is the model sample time.
Sample rate (Hz)
— Input signal sample rate1
(default)  positive scalarInput signal sample rate in hertz, specified as a positive scalar. To match the model settings, set the sample rate to N_{S}/T_{S}, where N_{S} is the number of input samples, and T_{S} is the model sample time.
This parameter appears when Inherit sample rate from input is not selected.
Data Types: double
Discrete path delays (s)
— Delays for each discrete path0
(default)  nonnegative scalar  row vectorDelays for each discrete path in seconds, specified as a nonnegative scalar or row vector.
When you set Discrete path delays (s) to a scalar, the SISO channel is frequency flat.
When you set Discrete path delays (s) to a vector, the SISO channel is frequency selective.
Data Types: double
Average path gains (dB)
— Average gain for each discrete path0
(default)  scalar  row vectorAverage gain for each discrete path in decibels, specified as a scalar or row vector. Average path gains (dB) must have the same size as Discrete path delays (s).
Data Types: double
Normalize average path gains to 0 dB
— Option to normalize average path gains to 0 dBSelect this parameter to normalize the fading processes so that the total power of the path gains, averaged over time, is 0 dB.
Fading distribution
— Fading distribution of channel Rayleigh
(default)  Rician
Select the fading distribution of the channel, either
Rayleigh
or Rician
.
Kfactors
— Kfactor of Rician fading channel3
(default)  positive scalar  row vector Kfactor of a Rician fading channel, specified as a positive scalar or a 1byN_{P} vector of positivevalued elements. N_{P} equals the value of the Discrete path delays (s) parameter.
If you set Kfactors to a scalar, the first discrete path is a Rician fading process with a Rician Kfactor of Kfactors. Any remaining discrete paths are independent Rayleigh fading processes.
If you set Kfactors to a row vector, the discrete path corresponding to a positive element of the Kfactors vector is a Rician fading process with a Rician Kfactor specified by that element. The discrete path corresponding to a zerovalued element of the Kfactors vector is a Rayleigh fading process.
This parameter appears when Fading distribution is Rician
.
Data Types: double
LOS path Doppler shifts (Hz)
— Doppler shifts for lineofsight components0
(default)  scalar  row vectorDoppler shifts for the lineofsight components of the Rician fading channel in hertz, specified as a scalar or row vector. This parameter must have the same size as Kfactors.
If you set LOS path Doppler shifts (Hz) to a scalar, it represents the lineofsight component Doppler shift of the first discrete path that is a Rician fading process.
If you set LOS path Doppler shifts (Hz) to a row vector, the discrete path that is a Rician fading process has its lineofsight component Doppler shift specified by the elements of LOS path Doppler shifts (Hz) that correspond to positive elements in the Kfactors vector.
This parameter appears when Fading distribution is Rician
.
Data Types: double
LOS path initial phases (rad)
— Initial phases for lineofsight components0
(default)  scalar  row vectorInitial phases for the lineofsight component of the Rician fading channel in radians, specified as a scalar or row vector. This parameter must have the same size as Kfactors.
If you set LOS path initial phases (rad) to a scalar, it is the lineofsight component initial phase of the first discrete path that is a Rician fading process.
If you set LOS path initial phases (rad) to a row vector, the discrete path that is a Rician fading process has its lineofsight component initial phase specified by the elements of LOS path initial phases (rad) that correspond to positive elements in the Kfactors vector.
This parameter appears when Fading distribution is Rician
.
Data Types: double
Maximum Doppler shift (Hz)
— Maximum Doppler shift for all channel paths0.001
(default)  nonnegative scalarMaximum Doppler shift for all channel paths in hertz, specified as a nonnegative scalar.
Maximum Doppler shift (Hz) must be smaller than (f_{s}/10)/f_{c} for each path. f_{s} is the sampling rate at the input to the SISO Fading Channel block. f_{c} is the cutoff frequency factor of the path. For more information, see Cutoff Frequency Factor.
Data Types: double
Doppler spectrum
— Doppler spectrum shape for all channel pathsdoppler('Jakes')
(default)  doppler('Flat')
 doppler('Rounded', ...)
 doppler('Bell', ...)
 doppler('Asymmetric Jakes', ...)
 doppler('Restricted Jakes', ...)
 doppler('Gaussian', ...)
 doppler('BiGaussian', ...)
Doppler spectrum shape for all channel paths, specified as a single Doppler spectrum
structure returned from the doppler
function or a
1byN_{P} cell array of such structures. The default
value of this parameter is the Jakes Doppler spectrum (doppler('Jakes')
).
If you assign a single call to doppler
, all paths have the same specified Doppler spectrum.
If you assign a 1byN_{P} cell array of calls
to doppler
using any of the specified syntaxes,
each path has the Doppler spectrum specified by the corresponding Doppler spectrum
structure in the array. In this case, N_{P} equals
the value of the Discrete path delays (s) parameter.
This parameter applies when Maximum Doppler shift (Hz) is greater than zero.
Initial seed
— Random number generator initial seed73
(default)  nonnegative integerRandom number generator initial seed for this block, specified as a nonnegative integer.
Output channel path gains
— Option to output channel path gainsSelect this parameter to add the Gain output port to the block and output the channel path gains of the underlying fading process.
Output channel filter delay
— Option to output channel filter delaySelect this parameter to add the Delay output port to the block and output the channel filter delay of the underlying fading process.
Simulate using
— Compilation typeInterpreted execution
(default)  Code generation
Compilation type, specified as Interpreted execution
or
Code generation
.
Interpreted execution
— Simulate model using the
MATLAB^{®} interpreter. This option shortens startup time but has slower simulation
speed than Code generation
.
Code generation
— Simulate model using generated C
code. The first time you run a simulation, Simulink^{®} generates C code for the block. The C code is reused for subsequent
simulations, as long as the model does not change. This option requires additional startup
time but provides faster simulation speed than Interpreted
execution
.
Channel visualization
— Select the channel visualizationOff
(default)  Impulse response
 Frequency response
 Doppler spectrum
 Impulse and frequency responses
Select the channel visualization: Off
, Impulse
response
, Frequency response
, Doppler
spectrum
, or Impulse and frequency responses
. When
visualization is on, the selected channel characteristics, such as impulse response or
Doppler spectrum, display in a separate window. For more information, see Channel
Visualization.
Percentage of samples to display
— Percentage of samples to display25%
(default)  10%
 50%
 100%
Select the percentage of samples to display: 10%
,
25%
, 50%
, or
100%
. Increasing the percentage improves display accuracy at the
expense of simulation speed.
This parameter appears when Channel visualization is Impulse response
,
Frequency response
, or Impulse and frequency
responses
.
Path for Doppler spectrum display
— Path for which Doppler spectrum is displayed1
(default)  positive integerPath for which the Doppler spectrum is displayed, specified as a positive integer from 1 to N_{P}, where N_{P} equals the value of the Discrete path delays (s) parameter.
This parameter appears when Channel visualization is Doppler spectrum
.
Data Types 

Multidimensional Signals 

VariableSize Signals 

The fading process for the SISO channel is described in Methodology for Simulating Multipath Fading Channels.
The following information explains how the cutoff frequency factor, f_{c}, is determined for different Doppler spectrum types:
For any Doppler spectrum type other than Gaussian and BiGaussian,
f_{c} equals 1
.
For a doppler
('Gaussian')
spectrum type,
f_{c} equals
NormalizedStandardDeviation∙sqrt(2∙log(2))
.
For a doppler
('BiGaussian')
spectrum type:
If the PowerGains(1)
and
NormalizedCenterFrequencies(2)
field values are
both 0
, then f_{c}
equals NormalizedStandardDeviation(1)∙sqrt(2∙log(2))
.
If the PowerGains(2)
and
NormalizedCenterFrequencies(1)
field values are
both 0
, then f_{c}
equals NormalizedStandardDeviation(2)∙sqrt(2∙log(2))
.
If the NormalizedCenterFrequencies
field value is
[0,0]
and the
NormalizedStandardDeviation
field has two identical
elements, then f_{c} equals
NormalizedStandardDeviation(1)∙sqrt(2∙log(2))
.
In all other cases, f_{c} equals
1
.
[1] Oestges, C., and B. Clerckx. MIMO Wireless Communications: From RealWorld Propagation to SpaceTime Code Design. Academic Press, 2007.
[2] Correira, L. M. Mobile Broadband Multimedia Networks: Techniques, Models and Tools for 4G. Academic Press, 2006.
[3] Kermoal, J. P., L. Schumacher, K. I. Pedersen, P. E. Mogensen, and F. Frederiksen. "A stochastic MIMO radio channel model with experimental validation." IEEE Journal on Selected Areas of Communications. Vol. 20, Number 6, 2002, pp. 1211–1226.
[4] Jeruchim, M., P. Balaban, and K. S. Shanmugan. Simulation of Communication Systems. Second Edition. New York: Kluwer Academic/Plenum, 2000.
[5] Pätzold, Matthias, ChengXiang Wang, and Bjorn Olav Hogstand. "Two New SumofSinusoidsBased Methods for the Efficient Generation of Multiple Uncorrelated Rayleigh Fading Waveforms." IEEE Transactions on Wireless Communications. Vol. 8, Number 6, 2009, pp. 3122–3131.
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