comm.OFDMModulator

Modulate signal using OFDM method

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Description

TheOFDMModulatorobject modulates a signal using the orthogonal frequency division modulation method. The output is a baseband representation of the modulated signal.

To modulate a signal using OFDM:

Create thecomm.OFDMModulatorobject and set its properties.
Call the object with arguments, as if it were a function.

To learn more about how System objects work, seeWhat Are System Objects?

Creation

Syntax

hMod = comm.OFDMModulator

hMod = comm.OFDMModulator(Name,Value)

hMod = comm.OFDMModulator(hDemod)

Description

example

hMod= comm.OFDMModulatorcreates an OFDM modulator System object™.

example

hMod= comm.OFDMModulator(Name,Value)specifiesPropertiesusing one of more name-value pair arguments. Enclose each property name in quotes. For example,comm.OFDMModulator('NumSymbols',8)specifies eight OFDM symbols in the time-frequency grid.

example

hMod= comm.OFDMModulator(hDemod)sets the OFDM modulator system object properties based on the specified OFDM demodulator system objectcomm.OFDMDemodulator.

Properties

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Unless otherwise indicated, properties arenontunable, which means you cannot change their values after calling the object. Objects lock when you call them, and thereleasefunction unlocks them.

If a property istunable, you can change its value at any time.

For more information on changing property values, seeSystem Design in MATLAB Using System Objects.

`FFTLength`—Number of FFT points
`64`(default) |positive integer

Number of Fast Fourier Transform (FFT) points, specified as a positive integer. The length of the FFT,N_FFT, must be greater than or equal to 8 and is equivalent to the number of subcarriers.

Data Types:double

`NumGuardBandCarriers`—Number of subcarriers to the left and right guard bands
`[6;5]`(default) |two-element column vector of integers

Number of subcarriers allocated to the left and right guard bands, specified as a two-element column vector of integers. The number of subcarriers must fall within [0,⌊N_FFT/2⌋ − 1]. This vector has the form [N_leftG,N_rightG], whereN_leftGandN_rightGspecify the left and right guard bands, respectively.

Data Types:double

`InsertDCNull`—Option to insert DC null
`false`or`0`(default) |`true`or`1`

Option to insert DC null, specified as a numeric or logical0(false) or1(true). The DC subcarrier is the center of the frequency band and has the index value:

(FFTLength/ 2) + 1 whenFFTLengthis even
(FFTLength+ 1) / 2 whenFFTLengthis odd

`PilotInputPort`—Option to specify pilot input
`false`or`0`(default) |`true`or`1`

Option to specify pilot input, specified as a numeric or logical0(false) or1(true). If this property is1(true), you can assign individual subcarriers for pilot transmission. If this property is0(false), pilot information is assumed to be embedded in the input data.

`PilotCarrierIndices`—Pilot subcarrier indices
`[12; 26; 40; 54]`(default) |column vector

Pilot subcarrier indices, specified as a column vector. If thePilotCarrierIndicesproperty is set to1(true), you can specify the indices of the pilot subcarriers. You can assign the indices to the same or different subcarriers for each symbol. Similarly, the pilot carrier indices can differ across multiple transmit antennas. Depending on the desired level of control for index assignments, the dimensions of the property vary. Valid pilot indices fall in the range

$[N_{leftG} + 1, N_{FFT} / 2] \cup [N_{FFT} / 2 + 2, N_{FFT} - N_{rightG}],$

where the index value cannot exceed the number of subcarriers. When the pilot indices are the same for every symbol and transmit antenna, the property has dimensionsN_pilot-by-1. When the pilot indices vary across symbols, the property has dimensionsN_pilot-by-N_sym. If you transmit only one symbol but multiple transmit antennas, the property has dimensionsN_pilot-by-1-by-N_t., whereN_t.是发射天线的数量。如果指数vary across the number of symbols and transmit antennas, the property has dimensionsN_pilot-by-N_sym-by-N_t. If the number of transmit antennas is greater than one, ensure that the indices per symbol must be mutually distinct across antennas to minimize interference.

To enable this property, set thePilotInputPortproperty to1(true).

`CyclicPrefixLength`—Length of cyclic prefix
`16`(default) |positive integer|row vector

Length of cyclic prefix, specified as a positive integer. If you specify a scalar, the prefix length is the same for all symbols through all antennas. If you specify a row vector of lengthN_sym, the prefix length can vary across symbols but remains the same through all antennas.

Data Types:double

`Windowing`—Option to apply raised cosine window between OFDM symbols
`false`or`0`(default) |`true`or`1`

Option to apply raised cosine window between OFDM symbols, specified astrueorfalse. Windowing is the process in which the OFDM symbol is multiplied by a raised cosine window before transmission to more quickly reduce the power of out-of-band subcarriers. Windowing reduces spectral regrowth.

`WindowLength`—Length of raised cosine window
`1`(default) |positive scalar

Length of raised cosine window, specified as a positive scalar. This value must be less than or equal to the minimum cyclic prefix length. For example, in a configuration of four symbols with cyclic prefix lengths 12, 14, 16, and 18, the window length must be less than or equal to 12.

To enable this property, set theWindowingproperty to1(true).

`NumSymbols`—Number of OFDM symbols
`1`(default) |positive integer

Number of OFDM symbols in the time-frequency grid, specified as a positive integer.

`NumTransmitAntennnas`—Number of transmit antennas
`1`(default) |positive integer

发射天线的数量,用于传输OFDM modulated signal, specified as a positive integer.

Usage

Syntax

waveform = hMod(insignal)

waveform = hMod(data,pilot)

Description

waveform= hMod(insignal)applies OFDM modulation the specified baseband signal and returns the modulated OFDM baseband signal.

waveform= hMod(data,pilot)assigns the pilot signal,pilot, into the frequency subcarriers specified by thePilotCarrierIndicesproperty value of thehModsystem object. To enable this syntax set thePilotCarrierIndicesproperty totrue.

Input Arguments

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`insignal`—Input baseband signal
matrix|3-D array

Input baseband signal, specified as a matrix or 3-D array of numeric values. The input baseband signal must be of sizeN_f-by-N_sym-by-N_t.whereN_fis the number of frequency subcarriers excluding guard bands and DC null.

Data Types:double
Complex Number Support:Yes

`data`—Input data
matrix|3-D array

Input data, specified as a matrix or 3-D array. The input must be a numeric of sizeN_d-by-N_sym-by-N_t.whereN_dis the number of data subcarriers in each symbol. For more information on howN_dis calculated, see thePilotCarrierIndicesproperty.

Data Types:double
Complex Number Support:Yes

`pilot`—Pilot signal
3-D array

Pilot signal, specified as a 3-D array of numeric values. The pilot signal must be of sizeN_pilot-by-N_sym-by-N_t.

Data Types:double
Complex Number Support:Yes

Output Arguments

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`waveform`— OFDM Modulated baseband signal
2-D array

OFDM Modulated baseband signal, returned as a 2-D array. If theCyclicPrefixLengthproperty is a scalar, the outputwaveformis of size((N_FFT+CP_len)⁎N_sym)-by-N_t. Otherwise, the size is(N_FFT⁎N_sym+∑(CP_len))-by-N_t.

Data Types:double
Complex Number Support:Yes

Object Functions

To use an object function, specify the System object as the first input argument. For example, to release system resources of a System object namedobj, use this syntax:

release(obj)

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Specific to`comm.OFDMModulator`

`info`	Provide dimensioning information for OFDM modulator
`showResourceMapping`	Show the subcarrier mapping of the OFDM symbols created by the OFDM modulatorSystem object

Common to All System Objects

`step`	RunSystem objectalgorithm
`release`	Release resources and allow changes toSystem objectproperty values and input characteristics
`reset`	Reset internal states ofSystem object

Examples

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Create and Modify OFDM Modulator

Open Live Script

Create and display an OFDM modulator System object™ with default property values.

hMod = comm.OFDMModulator

hMod = comm.OFDMModulator with properties: FFTLength: 64 NumGuardBandCarriers: [2x1 double] InsertDCNull: false PilotInputPort: false CyclicPrefixLength: 16 Windowing: false NumSymbols: 1 NumTransmitAntennas: 1

Modify the number of subcarriers and symbols.

hMod.FFTLength = 128; hMod.NumSymbols = 2;

Verify that the number of subcarriers and the number of symbols changed.

disp(hMod)

comm.OFDMModulator with properties: FFTLength: 128 NumGuardBandCarriers: [2x1 double] InsertDCNull: false PilotInputPort: false CyclicPrefixLength: 16 Windowing: false NumSymbols: 2 NumTransmitAntennas: 1

Use theshowResourceMappingobject function to show the mapping of data, pilot, and null subcarriers in the time-frequency space.

showResourceMapping(hMod)

Figure OFDM Subcarrier Mapping for All Tx Antennas contains an axes object. The axes object with title OFDM Subcarrier Mapping for All Tx Antennas contains an object of type image.

Create OFDM Modulator from OFDM Demodulator

Open Live Script

Create an OFDM demodulator System object™ with default property values. Then, specify pilot indices for a single symbol and two transmit antennas.

Setting thePilotCarrierIndicesproperty of the demodulator affects the number of transmit antennas in the OFDM modulator when you use the demodulator in the creation of the modulator. The number of receive antennas in the demodulator is uncorrelated with the number of transmit antennas.

ofdmDemod = comm.OFDMDemodulator; ofdmDemod.PilotOutputPort = true; ofdmDemod.PilotCarrierIndices =...cat(3,[12; 26; 40; 54],[13; 27; 41; 55]);

Use the OFDM demodulator to construct the OFDM modulator.

ofdmMod = comm.OFDMModulator(ofdmDemod);

Display the properties of the OFDM modulator and demodulator, verifying that the applicable properties match.

disp(ofdmMod)

comm.OFDMModulator with properties: FFTLength: 64 NumGuardBandCarriers: [2x1 double] InsertDCNull: false PilotInputPort: true PilotCarrierIndices: [4x1x2 double] CyclicPrefixLength: 16 Windowing: false NumSymbols: 1 NumTransmitAntennas: 2

disp(ofdmDemod)

comm.OFDMDemodulator with properties: FFTLength: 64 NumGuardBandCarriers: [2x1 double] RemoveDCCarrier: false PilotOutputPort: true PilotCarrierIndices: [4x1x2 double] CyclicPrefixLength: 16 NumSymbols: 1 NumReceiveAntennas: 1

Visualize Time-Frequency Resource Assignments for OFDM Modulator

Open Live Script

TheshowResourceMappingmethod displays the time-frequency resource mapping for each transmit antenna.

Construct an OFDM modulator.

mod = comm.OFDMModulator;

Apply theshowResourceMappingmethod.

showResourceMapping(mod)

Figure OFDM Subcarrier Mapping for All Tx Antennas contains an axes object. The axes object with title OFDM Subcarrier Mapping for All Tx Antennas contains an object of type image.

Insert a DC null.

mod.InsertDCNull = true;

Show the resource mapping after adding the DC null.

showResourceMapping(mod)

Figure OFDM Subcarrier Mapping for All Tx Antennas contains an axes object. The axes object with title OFDM Subcarrier Mapping for All Tx Antennas contains an object of type image.

Create OFDM Modulator and Specify Pilots

Open Live Script

Create an OFDM modulator and specify the subcarrier indices for the pilot signals. Specify the indices for each symbol and transmit antenna. When the number of transmit antennas is greater than one, set different pilot indices for each symbol between antennas.

Create an OFDM modulator System object, specifying two symbols and inserting a DC null.

mod = comm.OFDMModulator('FFTLength',128,'NumSymbols',2,...'InsertDCNull',true);

Enable the pilot input port so you can specify the pilot indices.

mod.PilotInputPort = true;

Specify the same pilot indices for both symbols.

mod.PilotCarrierIndices = [12; 56; 89; 100];

Visualize the placement of the pilot signals and nulls in the OFDM time-frequency grid by using theshowResourceMappingobject function.

showResourceMapping(mod)

Figure OFDM Subcarrier Mapping for All Tx Antennas contains an axes object. The axes object with title OFDM Subcarrier Mapping for All Tx Antennas contains an object of type image.

Specify different indices for the second symbol by concatenating a second column of pilot indices to thePilotCarrierIndicesproperty.

mod.PilotCarrierIndices = cat(2,mod.PilotCarrierIndices,...[17; 61; 94; 105]);

Verify that the pilot subcarrier indices differ between the two symbols.

showResourceMapping(mod)

Figure OFDM Subcarrier Mapping for All Tx Antennas contains an axes object. The axes object with title OFDM Subcarrier Mapping for All Tx Antennas contains 2 objects of type image, line.

Increase the number of transmit antennas to two.

mod.NumTransmitAntennas = 2;

Specify the pilot indices for each of the two transmit antennas. To provide indices for multiple antennas while minimizing interference among the antennas, set thePilotCarrierIndices房地产作为一个三维数组的索引each symbol differ among antennas.

mod.PilotCarrierIndices = cat(3,[20; 50; 70; 110], [15; 60; 75; 105]);

Display the resource mapping for the two transmit antennas. The gray lines denote the insertion of custom nulls. The nulls are created by the object to minimize interference among the pilot symbols from different antennas.

showResourceMapping(mod)

Figure OFDM Subcarrier Mapping for Tx Antenna 1 contains an axes object. The axes object with title OFDM Subcarrier Mapping for Tx Antenna 1 contains an object of type image.

Figure OFDM Subcarrier Mapping for Tx Antenna 2 contains an axes object. The axes object with title OFDM Subcarrier Mapping for Tx Antenna 2 contains an object of type image.

Create OFDM Modulator with Varying Cyclic Prefix Lengths

Open Live Script

Specify the length of the cyclic prefix for each OFDM symbol.

Create an OFDM modulator, specifying five symbols, four left and three right guard-band subcarriers, and the cyclic prefix length for each OFDM symbol.

mod = comm.OFDMModulator('NumGuardBandCarriers',[4;3],...'NumSymbols',5,...'CyclicPrefixLength',[12 10 14 11 13]);

Display the properties of the OFDM modulator, verifying that the cyclic prefix length changes across symbols.

disp(mod)

comm.OFDMModulator with properties: FFTLength: 64 NumGuardBandCarriers: [2x1 double] InsertDCNull: false PilotInputPort: false CyclicPrefixLength: [12 10 14 11 13] Windowing: false NumSymbols: 5 NumTransmitAntennas: 1

Determine OFDM Modulator Data Dimensions

Open Live Script

Get the OFDM modulator data dimensions by using theinfoobject function.

Construct an OFDM modulator System object™ with user-specified pilot indices, an inserted DC null, and specify two transmit antennas.

hMod = comm.OFDMModulator('NumGuardBandCarriers',[4;3],...'PilotInputPort',true,...'PilotCarrierIndices',cat(3,[12; 26; 40; 54],...[11; 25; 39; 53]),...'InsertDCNull',true,...'NumTransmitAntennas',2);

Use theinfoobject function to get the modulator input data, pilot input data, and output data sizes.

info(hMod)

ans =struct with fields:DataInputSize: [48 1 2] PilotInputSize: [4 1 2] OutputSize: [80 2]

Create OFDM Modulated Data

Open Live Script

Generate OFDM modulated symbols for use in link-level simulations.

Construct an OFDM modulator with an inserted DC null, seven guard-band subcarriers, and two symbols having different pilot indices for each symbol.

mod = comm.OFDMModulator(...'NumGuardBandCarriers',[4;3],...'PilotInputPort',true,...'PilotCarrierIndices',[12 11; 26 27; 40 39; 54 55],...'NumSymbols',2,...'InsertDCNull',true);

Determine input data, pilot, and output data dimensions.

modDim = info(mod);

Generate random data symbols for the OFDM modulator. The structure variable,modDim, determines the number of data symbols.

dataIn = complex(...randn(modDim.DataInputSize),randn(modDim.DataInputSize));

Create a pilot signal that has the correct dimensions.

pilotIn = complex(...rand(modDim.PilotInputSize),rand(modDim.PilotInputSize));

Apply OFDM modulation to the data and pilot signals.

modData = mod(dataIn,pilotIn);

Use the OFDM modulator object to create the corresponding OFDM demodulator.

demod = comm.OFDMDemodulator(mod);

Demodulate the OFDM signal and output the data and pilot signals.

[dataOut, pilotOut] = demod(modData);

Verify that, within a tight tolerance, the input data and pilot symbols match the output data and pilot symbols.

isSame = (max(abs([dataIn(:) - dataOut(:);...pilotIn(:) - pilotOut(:)])) < 1e-10)

isSame =logical1

More About

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Orthogonal Frequency Division Modulation

OFDM operation divides a high-rate data stream into lower data rate substreams by decomposing the transmission frequency band intoNcontiguous individually modulated subcarriers. Multiple parallel and orthogonal subcarriers carry the samples with almost the same bandwidth as a wideband channel. By using narrow orthogonal subcarriers, the OFDM signal gains robustness over a frequency-selective fading channel and eliminates adjacent subcarrier interference. Intersymbol interference (ISI) is reduced because the lower data rate substreams have symbol durations larger than the channel delay spread.

The Frequency domain representation of orthogonal subcarriers in an OFDM waveform looks as follows:

The transmitter applies inverse fast Fourier transform (IFFT) toNsymbols at a time. The output of the IFFT is the sum of theNorthogonal sinusoids:

$x (t) = \sum_{k = 0}^{N - 1} X_{k} e^{j 2 π k Δ f t}, 0 \leq t \leq T,$

where {X_k} are data symbols, andTis the OFDM symbol time. The data symbolsX_kare typically complex and can be from any digital modulation alphabet (for example, QPSK, 16-QAM, 64-QAM).

The subcarrier spacing is Δf= 1/T; ensuring that the subcarriers are orthogonal over each symbol period, as shown below:

$\frac{1}{T} \int_{0}^{T} {(e^{j 2 π m Δ f t})}^{*} (e^{j 2 π n Δ f t}) d t = \frac{1}{T} \int_{0}^{T} e^{j 2 π (m - n) Δ f t} d t = 0 for m \neq n .$

An OFDM modulator consists of a serial-to-parallel conversion followed by a bank ofNcomplex modulators, individually corresponding to each OFDM subcarrier.

Subcarrier Allocation, Guard Bands and Guard Intervals

Individual OFDM subcarriers are allocated as data, pilot, or null subcarriers.

As shown here, subcarriers are designated as data, DC, pilot, or guard band subcarriers.

Data subcarriers transmit user data.
Pilot subcarriers are used for channel estimation.
Null subcarriers transmit no data. Subcarriers with no data are used to provide a DC null and serve as buffers between OFDM resource blocks.
- The null DC subcarrier is the center of the frequency band with an index value of (nfft/2 + 1) ifnfftis even, or ((nfft+ 1) / 2) ifnfftis odd.
- The guard bands provide buffers between consecutive OFDM symbols to protect the integrity of transmitted signals by reducing intersymbol interference.

Null subcarriers enable you to model guard bands and DC subcarrier locations for specific standards, such as the various 802.11 formats, LTE, WiMAX, or for custom allocations. You can allocate the location of nulls by assigning a vector of null subcarrier indices.

Similar to guard bands, guard intervals are used in OFDM to protect the integrity of transmitted signals by reducing intersymbol interference.

Assignment of guard intervals is analogous to the assignment of guard bands. You can model guard intervals to provide temporal separation between OFDM symbols. The guard intervals help preserve intersymbol orthogonality after the signal passes through time-dispersive channels. Guard intervals are created by using cyclic prefixes. Cyclic prefix insertion copies the last part of an OFDM symbol as the first part of the OFDM symbol.

As long as the span of the time dispersion does not exceed the duration of the cyclic prefix, the benefit of cyclic prefix insertion is maintained.

Inserting a cyclic prefix results in a fractional reduction of user data throughput because the cyclic prefix occupies bandwidth that could be used for data transmission.

Raised Cosine Windowing

While the cyclic prefix creates a guard period in time domain to preserve orthogonality, an OFDM symbol rarely begins with the same amplitude and phase exhibited at the end of the prior OFDM symbol causing spectral regrowth and therefore, spreading of signal bandwidth due to intermodulation distortion. To limit this spectral regrowth, it is desired to create a smooth transition between the last sample of a symbol and the first sample of the next symbol. This can be done by using a cyclic suffix and raised cosine windowing.

To create the cyclic suffix, the firstN_WIN样本给定符号添加到结束of that symbol. However, in order to comply with the 802.11g standard, for example, the length of a symbol cannot be arbitrarily lengthened. Instead, the cyclic suffix must overlap in time and is effectively summed with the cyclic prefix of the following symbol. This overlapped segment is where windowing is applied. Two windows are applied, one of which is the mathematical inverse of the other. The first raised cosine window is applied to the cyclic suffix of symbolkand decreases from 1 to 0 over its duration. The second raised cosine window is applied to the cyclic prefix of symbolk+1 and increases from 0 to 1 over its duration. This process provides a smooth transition from one symbol to the next.

The raised cosine window,w(t), in the time domain can be expressed as:

$w (t) = {\begin{cases} 1, 0 \leq | t | < \frac{T - T_{W}}{2} \\ \frac{1}{2} {1 + \cos [\frac{π}{T_{W}} (| t | - \frac{T - T_{W}}{2})]}, \frac{T - T_{W}}{2} \leq | t | \leq \frac{T + T_{W}}{2} \\ 0, otherwise \end{cases}$

where:

Tis the OFDM symbol duration including the guard interval.
T_Wis the duration of the window.

Adjust the length of the cyclic suffix via the window length setting property, with suffix lengths set between 1 and the minimum cyclic prefix length. While windowing improves spectral regrowth, it does so at the expense of multipath fading immunity. This occurs because redundancy in the guard band is reduced because the guard band sample values are compromised by the smoothing.

The following figures display the application of raised cosine windowing.

References

[1] Dahlman, Erik, Stefan Parkvall, and Johan Sköld. 4G LTE/LTE-Advanced for Mobile Broadband. Amsterdam: Elsevier, Acad. Press, 2011.

[2] Andrews, J. G., A. Ghosh, and R. Muhamed.Fundamentals of WiMAX. Upper Saddle River, NJ: Prentice Hall, 2007.

[3] Agilent Technologies, Inc., "OFDM Raised Cosine Windowing",https://rfmw.em.keysight.com/wireless/helpfiles/n7617a/ofdm_raised_cosine_windowing.htm.

[4] Montreuil, L., R. Prodan, and T. Kolze. "OFDM TX Symbol Shaping 802.3bn",https://www.ieee802.org/3/bn/public/jan13/montreuil_01a_0113.pdf. Broadcom, 2013.

[5] "IEEE Standard 802.16™-2009." New York: IEEE, 2009.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

SeeSystem Objects in MATLAB Code Generation(MATLAB Coder).

Version History

Introduced in R2014a

comm.OFDMModulator

Description

Creation

Syntax

Description

Properties

FFTLength—Number of FFT points64(default) |positive integer

NumGuardBandCarriers—Number of subcarriers to the left and right guard bands[6;5](default) |two-element column vector of integers

InsertDCNull—Option to insert DC nullfalseor0(default) |trueor1

PilotInputPort—Option to specify pilot inputfalseor0(default) |trueor1

PilotCarrierIndices—Pilot subcarrier indices[12; 26; 40; 54](default) |column vector

CyclicPrefixLength—Length of cyclic prefix16(default) |positive integer|row vector

Windowing—Option to apply raised cosine window between OFDM symbolsfalseor0(default) |trueor1

WindowLength—Length of raised cosine window1(default) |positive scalar

NumSymbols—Number of OFDM symbols1(default) |positive integer

NumTransmitAntennnas—Number of transmit antennas1(default) |positive integer

Usage

Syntax

Description

Input Arguments

insignal—Input baseband signalmatrix|3-D array

data—Input datamatrix|3-D array

pilot—Pilot signal3-D array

Output Arguments

waveform— OFDM Modulated baseband signal2-D array

Object Functions

Specific tocomm.OFDMModulator

Common to All System Objects

Examples

Create and Modify OFDM Modulator

Create OFDM Modulator from OFDM Demodulator

Visualize Time-Frequency Resource Assignments for OFDM Modulator

Create OFDM Modulator and Specify Pilots

Create OFDM Modulator with Varying Cyclic Prefix Lengths

Determine OFDM Modulator Data Dimensions

Create OFDM Modulated Data

More About

Orthogonal Frequency Division Modulation

Subcarrier Allocation, Guard Bands and Guard Intervals

Raised Cosine Windowing

References

Extended Capabilities

C/C++ Code GenerationGenerate C and C++ code using MATLAB® Coder™.

Version History

See Also

Functions

Objects

Blocks

`FFTLength`—Number of FFT points
`64`(default) |positive integer

`NumGuardBandCarriers`—Number of subcarriers to the left and right guard bands
`[6;5]`(default) |two-element column vector of integers

`InsertDCNull`—Option to insert DC null
`false`or`0`(default) |`true`or`1`

`PilotInputPort`—Option to specify pilot input
`false`or`0`(default) |`true`or`1`

`PilotCarrierIndices`—Pilot subcarrier indices
`[12; 26; 40; 54]`(default) |column vector

`CyclicPrefixLength`—Length of cyclic prefix
`16`(default) |positive integer|row vector

`Windowing`—Option to apply raised cosine window between OFDM symbols
`false`or`0`(default) |`true`or`1`

`WindowLength`—Length of raised cosine window
`1`(default) |positive scalar

`NumSymbols`—Number of OFDM symbols
`1`(default) |positive integer

`NumTransmitAntennnas`—Number of transmit antennas
`1`(default) |positive integer

`insignal`—Input baseband signal
matrix|3-D array

`data`—Input data
matrix|3-D array

`pilot`—Pilot signal
3-D array

`waveform`— OFDM Modulated baseband signal
2-D array

Specific to`comm.OFDMModulator`

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.