stdchan

Construct channel System object from set of standardized channel models

Syntax

chan = stdchan(chantype,rs,fd)

Description

chan = stdchan(chantype,rs,fd) constructs a fading channel object chan according to the specified chantype. chantype is chosen from the channel models listed in Supported Standards. rs is the sampling rate of the input signal and fd is the maximum Doppler shift.

example

Examples

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Filter Signal Through CDMA Channel

Open Live Script

Set the sample rate and the maximum Doppler shift.

rs = 20e6;
fd = 3;

Create a CDMA Typical Urban channel model (TUx) channel object and turn on frequency response visualization.

chan = stdchan('cdmaTUx',rs,fd);
chan.Visualization = 'Frequency response';

Generate random data and apply QPSK modulation.

data = randi([0 3],10000,1);
txSig = pskmod(data,4,pi/4);

Filter the QPSK signal through the CDMA channel.

y = chan(txSig);

GSM and EDGE Channel Model

Open Live Script

Create a channel model useful for GSM and EDGE simulations. Experiment with low speed and high speed conditions.

Configure Parameters and System Objects

Define variables for the frame configuration.

M = 8;               % Modulation order, 8-PSK
phaseoffset = 0;     % Phase offset for 8-PSK symbols
Rbit = 9600;         % Input bit rate
Rs = Rbit / log2(M); % Symbol rate
Nsamples = 5e2;      % Number of samples per frame
Nframes = 10;        % Number of frames

Define the channel configuration for low speed mobile and create a standard channel System object for the equalization test (EQx) with 6 taps profile.

v = 10 * 1e3 / 3600;         % Mobile speed (m/s)
fc = 1800e6;                 % Carrier frequency
c = physconst('LightSpeed'); % Speed of light in free space
fd = v * fc / c;         % Maximum Doppler shift of diffuse component

channel = stdchan('gsmEQx6',Rs,fd);
channel.RandomStream = 'mt19937ar with seed'; % set for reproducibility
channel.Visualization = 'Impulse and frequency responses';
channel.SamplesToDisplay = '100%';

Create a constellation diagram System object.

refC = pskmod(0:M-1,M,phaseoffset);
constDiagram = comm.ConstellationDiagram( ...
    ReferenceConstellation=refC, ...
    XLimits=[-3 3], ...
    YLimits=[-3 3]);

Simulate at Low Speed

for iFrames = 1:Nframes
    msg = randi([0 M-1],Nsamples,1);
    modSignal = pskmod(msg,M,phaseoffset);
    chanOut = channel(modSignal);
    constDiagram(chanOut);
end

Simulate at High Speed

Release and reconfigure the channel and constellation diagram objects.

release(constDiagram);
release(channel);

v = 120 * 1e3 / 3600; % Mobile speed (m/s)
fd = v * fc / c;      % Maximum Doppler shift of diffuse component

channel.MaximumDopplerShift = fd; % Adjust maximum doppler shift

for iFrames = 1:Nframes
    msg = randi([0 M-1],Nsamples,1);
    modSignal = pskmod(msg,M,phaseoffset);
    chanOut = channel(modSignal);
    constDiagram(chanOut);
end

Input Arguments

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`chantype` — Channel type
string | character vector

Channel type, specified as a string or character vector. Valid options are listed in Supported Standards.

Example: stdchan('gsmRAx6c1',rs,fd), configures a channel model for the GSM typical case for rural area (RAx), 6 taps, case 1, with a sample rate rs, and maximum Doppler shift fd

Data Types: char | string

`rs` — Sample rate
scalar

Sample rate in Hertz, specified as a scalar.

Data Types: double

`fd` — Maximum Doppler shift
scalar

Maximum Doppler shift in Hertz, specified as a scalar.

Data Types: double

Output Arguments

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`chan` — Channel object
System object™

Channel object, returned as a comm.RayleighChannel or comm.RicianChannel System object.

More About

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Supported Standards

For GSM, CDMA, and ITU-R HF standards, call stdchan to return a comm.RayleighChannel or comm.RicianChannel System object modeling one of these profiles.

GSM/EDGE channel models (3GPP TS 45.005 V7.9.0 (2007-2), 3GPP TS 05.05 V8.20.0 (2005-11)):

Channel model	Profile
`gsmRAx6c1`	Typical case for rural area (RAx), 6 taps, case 1
`gsmRAx4c2`	Typical case for rural area (RAx), 4 taps, case 2
`gsmHTx12c1`	Typical case for hilly terrain (HTx), 12 taps, case 1
`gsmHTx12c2`	Typical case for hilly terrain (HTx), 12 taps, case 2
`gsmHTx6c1`	Typical case for hilly terrain (HTx), 6 taps, case 1
`gsmHTx6c2`	Typical case for hilly terrain (HTx), 6 taps, case 2
`gsmTUx12c1`	Typical case for urban area (TUx), 12 taps, case 1
`gsmTUx12c1`	Typical case for urban area (TUx), 12 taps, case 2
`gsmTUx6c1`	Typical case for urban area (TUx), 6 taps, case 1
`gsmTUx6c2`	Typical case for urban area (TUx), 6 taps, case 2
`gsmEQx6`	Profile for equalization test (EQx), 6 taps
`gsmTIx2`	Typical case for very small cells (TIx), 2 taps

CDMA channel models for deployment evaluation (3GPP TR 25.943 V6.0.0 (2004-12)):

Channel model	Profile
`cdmaTUx`	Typical Urban channel model (TUx)
`cdmaRAx`	Rural Area channel model (RAx)
`cdmaHTx`	Hilly Terrain channel model (HTx)

ITU-R HF channel models (ITU-R F.1487 (2000)) (FD must be 1 to obtain the correct frequency spreads for these models.):

Channel model	Profile
`iturHFLQ`	Low latitudes, Quiet conditions
`iturHFLM`	Low latitudes, Moderate conditions
`iturHFLD`	Low latitudes, Disturbed conditions
`iturHFMQ`	Medium latitudes, Quiet conditions
`iturHFMM`	Medium latitudes, Moderate conditions
`iturHFMD`	Medium latitudes, Disturbed conditions
`iturHFMDV`	Medium latitudes, Disturbed conditions near vertical incidence
`iturHFHQ`	High latitudes, Quiet conditions
`iturHFHM`	High latitudes, Moderate conditions
`iturHFHD`	High latitudes, Disturbed conditions

Version History

Introduced in R2007b

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R2020b: Syntax has been removed

stdchan(ts,fd,chanType) syntax has been removed.

Compatibility considerations for the stdchan function includes addition of a function syntax, removal of a function syntax, and removal of configuration support for several channel models.

The syntax chan = stdchan(ts,fd,chantype) has been removed. A System object is returned using the new syntax.

stdchan has removed support for configuration of several channel models by supported standards and associated syntax, compatibility considerations are indicated here:

Standard	Previous Syntax	New Syntax to Return System Object	Notes
3GPP, CDMA	`stdchan(ts,fd,'3gppXXX')`	`stdchan('cdmaXXX',rs,fd)`	Prefix changed from '`3gpp`' to '`cdma`'. `ts` and `rs` are reciprocal values.
GSM	`stdchan(ts,fd,'gsmXXX')`	`stdchan('gsmXXX',rs,fd)`	`ts` and `rs` are reciprocal values.
ITU-R HF	`stdchan(ts,fd,'iturHFXXX')`	`stdchan('iturHFXXX',rs,fd)`	`ts` and `rs` are reciprocal values.
COST207	`stdchan(ts,fd,'cost207XXX')`	N/A	In the future `stdchan` will not configure these channels. Use `comm.RayleighChannel` or `comm.RicianChannel` to configure the channel models for COST207, ITU-R 3G, JTC, HIPERLAN/2, and 802.11a/b/g standards. For guidance mapping parameters, see Rayleigh Channel Compatibility Considerations and Rician Channel Compatibility Considerations.
ITU-R 3G	`stdchan(ts,fd,'itur3GXXX')`	N/A
JTC	`stdchan(ts,fd,'jtcXXX')`	N/A
HIPERLAN/2	`stdchan(ts,fd,'hiperlan2XXX')`	N/A
802.11a/b/g	`stdchan(ts,fd,'802.11X')`	N/A

Rayleigh Channel Compatibility Considerations

Replace instances of rayleighchan with a comm.RayleighChannel System object. Note the mapping between function parameters and object properties:

Comparison Between rayleighchan and comm.RayleighChannel
rayleighchan		comm.RayleighChannel		Notes
Properties	Associated functions	Properties	Object functions	Notes
`ChannelType`				Indicated by System object name
`InputSamplePeriod`		`SampleRate`		Value is reciprocal
`DopplerSpectrum`		`DopplerSpectrum`
`MaxDopplerShift`		`MaximumDopplerShift`
`PathDelays`		`PathDelays`
`AvgPathGaindB`		`AveragePathGains`
`NormalizePathGains`		`NormalizePathGains`
`StoreHistory`				Adjacent with the `plot` function of `rayleighchan`
`PathGains`			object call (`step`)	Second output returned by a call of the object (`step`)
`ChannelFilterDelay`			`info`	Returned by a call to `info`
`ResetBeforeFiltering`			`reset`	Call `reset` before each object function call (`step`)
`NumSamplesProcessed`			`info`	Returned by a call to `info`
	`filter`		object call (`step`)	First output returned by a call of the object (`step`)
	`reset`		`reset`
	`plot`	`Visualization` `SamplesToDisplay` `PathsForDopplerDisplay`	object call (`step`)	The `Visualization` property setting controls display of graphics during an object call (`step`).
`StorePathGains`		`PathGainsOutputPort`

Rician Channel Compatibility Considerations

Replace instances of ricianchan with a comm.RicianChannel System object. Note the mapping between function parameters and object properties:

Comparison Between ricianchan and comm.RicianChannel
ricianchan		comm.RicianChannel		Notes
Properties	Associated functions	Properties	Object functions	Notes
`ChannelType`				Indicated by System object name
`InputSamplePeriod`		`SampleRate`		Value is reciprocal
`DopplerSpectrum`		`DopplerSpectrum`
`MaxDopplerShift`		`MaximumDopplerShift`
`PathDelays`		`PathDelays`
`KFactor`		`KFactor`
`DirectPathDopplerShift`		`DirectPathDopplerShift`
`DirectPathInitPhase`		`DirectPathInitialPhase`
`AvgPathGaindB`		`AveragePathGains`
`NormalizePathGains`		`NormalizePathGains`
`StoreHistory`				Adjacent with the `plot` function of `ricianchan`
`StorePathGains`		`PathGainsOutputPort`
`PathGains`			object call (`step`)	Second output returned by a call of the object (`step`)
`ChannelFilterDelay`			`info`	Returned by a call to `info`
`ResetBeforeFiltering`			`reset`	Call `reset` before each object function call (`step`)
`NumSamplesProcessed`			`info`	Returned by a call to `info`
	`filter`		object call (`step`)	First output returned by a call of the object (`step`)
	`reset`		`reset`
	`plot`	`Visualization` `SamplesToDisplay` `PathsForDopplerDisplay`	object call (`step`)	The `Visualization` property setting controls display of graphics during an object call (`step`).

stdchan

Syntax

Description

Examples

Filter Signal Through CDMA Channel

GSM and EDGE Channel Model

Input Arguments

`chantype` — Channel type
string | character vector

`rs` — Sample rate
scalar

`fd` — Maximum Doppler shift
scalar

Output Arguments

`chan` — Channel object
System object™

More About

Supported Standards

Version History

R2020b: Syntax has been removed

See Also

Functions

Objects

stdchan

Syntax

Description

Examples

Filter Signal Through CDMA Channel

GSM and EDGE Channel Model

Input Arguments

chantype — Channel type string | character vector

rs — Sample rate scalar

fd — Maximum Doppler shift scalar

Output Arguments

chan — Channel object System object™

More About

Supported Standards

Version History

R2020b: Syntax has been removed

See Also

Functions

Objects

`chantype` — Channel type
string | character vector

`rs` — Sample rate
scalar

`fd` — Maximum Doppler shift
scalar

`chan` — Channel object
System object™