OFDM Modulator

Modulate frequency-domain OFDM subcarriers to time-domain samples for custom communication protocols

Since R2020a

Libraries:
Wireless HDL Toolbox / Modulation

Description

The OFDM Modulator block modulates frequency-domain orthogonal frequency division multiplexing (OFDM) subcarriers to time-domain samples based on the OFDM parameters. The block supports 5G new radio (NR) standard, long term evolution (LTE) [1], wireless local area network (WLAN 802.11a/g/n/ac) [2], WiMAX, digital video broadcast (DVB), and digital audio broadcast (DAB) standards.

The block accepts input data along with a valid control signal and these OFDM parameters: FFT length, CP length, and the number of right and left guard subcarriers. The block outputs modulated data along with valid and ready controls signals. The block samples the corresponding OFDM parameters only when the ready port is 1 (high) and when the first valid port of each OFDM symbol is 1 (high).

The block supports scalar and vector inputs. You can use a vector input to increase the data throughput and achieve a giga-sample-per-second (GSPS) throughput. The block supports windowing for scalar and vector inputs to reduce the spectral regrowth, or adjacent channel leakage ratio (ACLR), of an OFDM signal. The block provides an interface and architecture suitable for HDL code generation and hardware deployment.

Examples

Modulate and Demodulate OFDM Streaming Samples

Modulate and demodulate OFDM streaming samples.

Open Script

Ports

Input

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data — Input data
scalar | column vector

Input data, specified as a scalar or column vector of real or complex values. The vector size must be a power of 2 and in the range from 1 to 64, and less than or equal to the FFT length. For more information on how to specify vector inputs, see Specifying Vector Input.

The software supports double and single data types for simulation, but not for HDL code generation.

Data Types: single | double | int8 | int16 | int32 | signed fixed point
Complex Number Support: Yes

valid — Indicates valid input data
scalar

Indicates valid input data, specified as a scalar.

This port is a control signal that indicates when the sample from the data input port is valid. When this value is 1, the block captures the values on the data input port. When this value is 0, the block ignores the values on the data input port.

Data Types: Boolean

FFTLen — Length of FFT
scalar

Length of the FFT, specified as a scalar. The FFT length must be power of 2 and in the range from 8 to 65,536. This value must be less than or equal to the Maximum FFT length parameter value.

To support the minimum FFT length of 8, the FFTLen data type must be fixdt(0,k,0), where k is greater than or equal to 4.

Dependencies

To enable this port, set the OFDM parameters source parameter to Input port.

CPLen — Length of cyclic prefix
scalar

Length of the cyclic prefix, specified as a scalar in the range from 0 to FFTLen.

To support the minimum FFT length of 8, the CPLen data type must be fixdt(0,k,0), where k is greater than or equal to 4.

Dependencies

To enable this port, set the OFDM parameters source parameter to Input port.

numLgSc — Number of left guard carriers of OFDM symbol
scalar

Number of left guard carriers of the OFDM symbol, specified as a scalar in the range from 0 to (FFTLen/2) – 1.

To support the minimum FFT length of 8, the numLgSc data type must be fixdt(0,k,0), where k is greater than or equal to 2.

Dependencies

To enable this port, set the OFDM parameters source parameter to Input port.

numRgSc — Number of right guard carriers of OFDM symbol
scalar

Number of right guard carriers of the OFDM symbol, specified as a scalar in the range from 0 to (FFTLen/2) – 1.

To support the minimum FFT length of 8, the numRgSc data type must be fixdt(0,k,0), where k is greater than or equal to 2.

Dependencies

To enable this port, set the OFDM parameters source parameter to Input port.

reset — Clear internal states
scalar

Clear internal states, specified as a Boolean scalar. When this value is 1, the block stops the current calculation and clears all internal states.

Dependencies

To enable this port, select the Enable reset input port parameter.

Data Types: Boolean

winLen — Length of window
scalar

Length of the window for overlap-adding of adjacent OFDM symbols, specified as a scalar in the range from 1 to Maximum window length.

Dependencies

To enable this port, set the OFDM parameters source parameter to Input port.

Output

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data — Modulated output data
scalar | column vector

Modulated output data, returned as a complex-valued scalar or a column vector. The data type of the output is dependent on the data type of the input data port.

When you set the OFDM parameters source parameter to Property and clear the Divide butterfly outputs by two parameter, the output word length increases by log₂(FFT length) bits.
When you set the OFDM parameters source parameter to Input port and clear the Divide butterfly outputs by two parameter, the output word length increases by log₂(Maximum FFT length) bits.

To avoid overflow, select the Divide butterfly outputs by two parameter.

Data Types: single | double | int8 | int16 | int32 | signed fixed point
Complex Number Support: Yes

valid — Indicates valid output data
scalar

Indicates valid output data, returned as a scalar.

This port is a control signal that indicates when the data output port is valid. The block sets this value to 1 when the data samples are available on the data output port.

Data Types: Boolean

ready — Indicates block is ready
scalar

Indicates block is ready, returned as a scalar.

This is a control signal that indicates when the block is ready for new input data. When this value is 1, the block accepts input data in the next time step. When this value is 0, the block ignores input data in the next time step.

Data Types: Boolean

Parameters

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Main

OFDM parameters source — Source of OFDM parameters
`Property` (default) | `Input port`

You can set OFDM parameters with an input port or by selecting a value for the parameter.

Select Property to enable the FFT length, Cyclic prefix length, Number of left guard subcarriers, and Number of right guard subcarriers parameters.

Select Input port to enable the FFTLen, CPLen, numLgSc, and numRgSc input ports and the Maximum FFT length parameter. The Maximum FFT length parameter sets the upper bound of the range of valid values for the FFTLen input port.

Maximum FFT length — Maximum length of FFT length
`64` (default) | power of 2 in range from 8 to 65,536

Specify the maximum length of the FFT.

Dependencies

To enable this parameter, set the OFDM parameters source parameter to Input port.

FFT length — Length of FFT
`64` (default) | power of 2 in range from 8 to 65, 536

Specify the FFT length.

When you set the OFDM parameters source parameter to Property, the block uses the FFT length value as the maximum FFT length.

Dependencies

To enable this parameter, set the OFDM parameters source parameter to Property.

Cyclic prefix length — Length of cyclic prefix
`16` (default) | integer in range from 0 to FFT length

Specify the length of the cyclic prefix.

Dependencies

To enable this parameter, set the OFDM parameters source parameter to Property.

Number of left guard subcarriers — Number of guard band subcarriers in left extreme of OFDM symbol
`6` (default) | integer in range from 0 to (FFT length/2) – 1

Specify the number of left guard subcarriers.

Dependencies

To enable this parameter, set the OFDM parameters source parameter to Property.

Number of right guard subcarriers — Number of guard band subcarriers in right extreme of OFDM symbol
`5` (default) | integer in range from 0 to (FFT length/2) – 1

Specify the number of right guard subcarriers.

Dependencies

To enable this parameter, set the OFDM parameters source parameter to Property.

Insert DC Null — Option to insert DC null
`on` (default) | `off`

Select this parameter to insert a null on the DC subcarrier.

Enable reset input port — Reset signal
`off` (default) | `on`

Select this parameter to enable the reset input port.

Windowing — Spectral growth reduction
`off` (default) | `on`

Select this parameter to perform a windowing operation that reduces spectral growth based on the specified window length. Clear this parameter to disable the windowing operation. For more information about windowing, see Windowing.

Window length — Length of window
`4` (default) | even integer in range from 1 to Cyclic prefix length

Specify the window length to overlap-add adjacent OFDM symbols.

Dependencies

To enable this parameter, set the OFDM parameters source parameter to Property and select the Windowing parameter.

Maximum window length — Maximum length of window
`8` (default) | integer in the range from 1 to CPLen

Specify the maximum window length.

Dependencies

To enable this parameter, set the OFDM parameters source parameter to Input port and select the Windowing parameter.

IFFT Parameters

Divide butterfly outputs by two — Divide FFT butterfly outputs by two
`on` (default) | `off`

This parameter controls the scaling option of the IFFT block inside the OFDM Modulator block.

When you select this parameter, the FFT implements an overall 1/N scale factor by dividing the output of each butterfly multiplication by two. This adjustment keeps the output of the IFFT in the same amplitude range as its input. If you clear this parameter, the block avoids overflow by increasing the word length by one bit after each butterfly multiplication.

Rounding Method — Rounding mode for internal fixed-point calculations
`Floor` (default) | `Ceiling` | `Convergent` | `Nearest` | `Round` | `Zero`

This parameter specifies the type of rounding mode for internal fixed-point calculations. For more information about rounding modes, see Rounding Modes. When the input is any integer data type or fixed-point data type, the FFT algorithm uses fixed-point arithmetic for internal calculations. This parameter does not apply when the input is of data type single or double. Rounding applies to twiddle-factor multiplication and scaling operations.

More About

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Specifying Vector Input

The OFDM Modulator block accepts active input subcarriers, which are calculated using the formula FFT length - (Number of left guard subcarriers + Number of right guard subcarriers + Insert DC Null). When you specify a vector input, if the number of active input subcarriers are insufficient to accommodate the vector length of data samples, you must pad zeros to the input to make it a complete vector. For example, if the number of active data subcarriers is 62, and the vector length is 16, you can specify the 48 data samples in 3 valid cycles and the remaining 14 data samples in the 4th valid cycle by padding two zeros to match the vector length of 16. If the number of active data subcarriers is 64, and the vector length is 16, you can specify the complete data samples in 4 valid cycles.

The block outputs Cyclic prefix length + FFT length number of samples. If the output data samples returned are insufficient to accommodate the vector length, the block stores the remaining samples and outputs them along with the data samples in the first valid cycle of the next data symbol. For example, if the number of data samples to be returned is 62, and the specified vector length is 16, the block returns 48 data samples in 3 valid cycles, stores the remaining 14 data samples and outputs them in the first output valid cycle of the next data symbol. If the number of data samples to be returned is 64, and the specified vector length is 16, the block returns data samples in 4 valid cycles.

Example 1

For a vector input of size 32 with block parameter FFT length set to 64, Cyclic prefix length set to 16, Number of left guard subcarriers set to 6, Number of right guard subcarriers set to 5, and Insert DC Null set to off, the block accepts 53 active data subcarriers.

In the figure, D1 and D2 indicate the active data subcarriers, Z indicates padded zeros, and S1 and S2 indicate modulated output data symbols.

To provide 53 active data subcarriers of vector length 32, two cycles are needed. In this case, you must send the first set of data samples as D1(1:32), send the second set of data samples as D1(33:53), and pad the remaining samples with zeros Z(1:11) to make the complete vector. Similarly, the block processes D2 based on the block parameter values.

The block outputs Cyclic prefix length + FFT length number of samples, which means 80 data samples in this example. In the figure, S1(1:16) contains the added cyclic prefix, and S1(17:80) contains the data samples of the first data symbol S1, which is returned as S1(17:32), S1(33:64), and the remaining 16 data samples S1(65:80) stored and returned at the first valid cycle of the second data symbol S2. Similarly, the block outputs S2 based on the block parameter values as shown in the figure.

Example 2

For a vector input of size 32 with block inputs FFTLen, CPLen, numLgSc, and numRgSc specified as 128, 10, 28, and 27, respectively, at the first valid high cycle and with block parameter Insert DC Null set to on, the block accepts 72 active data subcarriers.

In the figure, D1 and D2 indicate the active data subcarriers, Z indicates padded zeros, and S1 and S2 indicate modulated output data symbols.

To provide 72 active data subcarriers of vector length 32, three cycles are needed. In this case, you must send the first set of data samples as D1(1:32), send the second set of data samples as D1(33:64), send the third set of data samples as D1(65:72), and pad the remaining samples with zeros Z(1:24) to make the complete vector. Similarly, the block processes D2 based on the port values.

The block outputs Cyclic prefix length + FFT length number of samples, which means 138 data samples in this example. In the figure, the output S1(1:10) contains the added cyclic prefix, and S1(11:138) contains the data samples of the first data symbol S1, which is returned as S1(11:32), S1(33:64), S1(65:96), S1(97:128), and the remaining 10 data samples S1(129:138) stored and returned at the first valid cycle of the second data symbol S2. Similarly, the block outputs S2 based on the port values shown in the figure.

Algorithms

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The OFDM Modulator block operation sequence is implemented using these blocks: Ready Generator, Symbol Formation, Sample Repeater, IFFT, FFT Shifter, Down Sampler, CP Addition, and Windowing. The windowing feature is supported for scalar and vector inputs. The parameters shown in this figure configure the behavior of the block.

OFDM Modulator Block Diagram

Ready Generator

The Ready Generator subsystem controls input data samples by calculating the number of active data subcarriers based on these input OFDM parameters: FFT length, CP length, number of left and right guard carriers, and DC null insertion status.

When you set the OFDM parameters source parameter to Property, these equations apply.

N_h = ceil((FFT length – (Number of left guard subcarriers + Number of right guard subcarriers + Insert DC Null))/vecLen)
N_l = ceil((FFT length + Cyclic prefix length))/vecLen) – N_h

When you set the OFDM parameters source parameter to Input port, these equations apply.

N_h = ceil((FFTLen – (numLgSc + numRgSc + Insert DC Null))/vecLen)
N_l = ceil((Maximum FFT length + CPLen))/vecLen) – N_h

In these equations,

N_h is the number of high ready clock cycles
N_l is the number of low ready clock cycles
vecLen is the length of the vector

This figure shows the ready signal generation for the default block configuration (FFT length = 64, Cyclic prefix length = 16, Number of left guard subcarriers = 6, Number of right guard subcarriers = 5 and Insert DC Null = on) with a scalar input.

Symbol Formation

The block stores input valid active subcarrier data, reads it, and forms a symbol of FFT length by placing the data at the center, and guard subcarriers at the edges of the symbol based on the number of left and right guard subcarrier values provided.

Sample Repeater

This block repeats FFT-length number of samples until it forms the maximum FFT length. For this operation, the block buffers the input samples first and then repeats the samples based on the maximum FFT length value. This repetition mechanism helps to avoid scaling at the FFT block input. This block is optional and available only when you set the OFDM parameters source parameter to Input port. When you set the OFDM parameters source parameter to Property, the FFT length value provided in the block mask is set as the maximum FFT length. The block does not need to repeat the samples in this context.

For example, if the FFT length is 128 and the maximum FFT length is 2048, each OFDM symbol consists of 128 samples. The block converts these 128 samples to 2048 samples by repeating the 128 samples 16 times. After the block generates 2048 data samples, it sends data and valid input signals to the next block.

IFFT

The IFFT block converts a frequency-domain signal to a time-domain signal. The block supports the FFT length as a power of 2, in the range from 8 to 65, 536.

The Divide butterfly outputs by two parameter sets whether the FFT implements an overall 1/N scale factor by dividing the output of each butterfly multiplication by two. This adjustment keeps the output of the IFFT in the same amplitude range as its input. When you clear the Divide butterfly outputs by two parameter, the block avoids overflow by increasing the word length by 1 bit after each butterfly multiplication.

Time-Domain FFT Shifter

Conventionally, transceivers perform an FFT shift in the frequency domain. However, this method requires memory and introduces latency related to the size of the FFT. Instead, a transceiver can execute the same operation in the time domain by using the frequency shifting property of Fourier transforms. Shifting a function in one domain corresponds to a multiplication by a complex exponential function in the other domain. To reduce hardware resources and latency, this block performs the FFT shift by multiplying the time-domain samples by a complex exponential function.

These equations describe an FFT shift. The equation for an N-point FFT is

$X (k) = F [x (n)] = \sum_{n = 0}^{N - 1} x (n) e^{- \frac{j 2 π n k}{N}}$

For an FFT shift of N/2 carriers in either direction, substitute $k = k - \frac{N}{2}$ , resulting in

$X (k - \frac{N}{2}) = \sum_{n = 0}^{N - 1} x (n) e^{- \frac{j 2 π n (k - \frac{N}{2})}{N}}$

This equation simplifies to

$X (k - \frac{N}{2}) = \sum_{n = 0}^{N - 1} e^{j π n} x (n) e^{- \frac{j 2 π n k}{N}}$

Since $\sum_{n = 0}^{N - 1} x (n) e^{- \frac{j 2 π n k}{N}}$ is equivalent to $F [x (n)]$ , and $e^{j π} = - 1$ , this equation simplifies to

$X (k - \frac{N}{2}) = F [{(- 1)}^{n} x (n)]$

The final equation shows that an FFT shift in the time domain simplifies to multiplication by (-1)ⁿ. Therefore, the block implements the FFT shift by multiplying the time-domain samples by either +1 or –1.

Down Sampler

This block down samples the maximum FFT length number of samples to FFT length number of samples. This block is optional and available only when the OFDM parameters source parameter is set to Input port. When OFDM parameters source is set to Property, the FFT length value provided in the block mask is considered as the maximum FFT length. So, there is no need to downsample the samples in this context.

For example, the block is operating with FFT length as 128 and the maximum FFT length is 2048. Here, the input is 2048 samples and it must be downsampled with respective to the FFT length 128. So, the block samples 1 sample for every 16 samples.

CP Addition

Cyclic prefix addition is the process of adding the last samples of an OFDM symbol as a prefix to each OFDM symbol. This figures shows CP addition for an OFDM symbol with Nfft samples and CP samples N_CP.

When the OFDM Modulator block operates through Input portselection, it uses the Maximum FFT length parameter to avoid multiple IFFTs.

Windowing

Windowing reduces the spectral regrowth, or adjacent channel leakage ratio (ACLR), of an OFDM signal. Windowing is optional and supports scalar and vector inputs. To enable windowing, select the Windowing parameter.

The blocks performs windowing on the CP-added OFDM symbols. For more information about windowing, see the OFDM Modulator Baseband block.

Latency

The latency of the block varies with the type of input: scalar or vector.

Scalar Input

This figure shows a sample output and latency of the OFDM Modulator block when you specify a scalar input, set the OFDM parameters source parameter to Property and use default settings for the other block parameters. FFT length is set to 64, Cyclic prefix length is set to 16, Insert DC null status is set to on, and Number of left guard subcarriers and Number of right guard subcarriers are set to 6 and 5, respectively.

In this example, the latency of the block is calculated using this formula: 2 x FFT length + IFFTLatency + 22, where IFFTLatency is the latency of IFFT block for the specified FFT length, and 22 is the number of pipeline delays.

This calculation shows that the latency of the block is 323 clock cycles, as shown in this figure.

OFDM Modulator Block Latency for Scalar Input Property

This figure shows a sample output and latency of the block when you specify a scalar input and set the OFDM parameters source parameter to Input port. For this example, FFTLen is set to 64, CPLen is set to 16, Insert DC null status is set to on, numLgSc and numRgSc are set to 6 and 5, respectively, and Maximum FFT length is set to 128.

In this example, the latency of the block is calculated using this formula: 2 x FFTLen + IFFTLatency + Maximum FFT length + (Maximum FFT length/FFTLen – 1) + 32, where IFFTLatency is the latency of IFFT block for the specified maximum FFT length, and 32 is the number of pipeline delays.

This calculation shows that the latency of the block is 594 clock cycles, as shown in this figure.

OFDM Modulator Block Latency for Scalar Input Port

The block accepts input only when the ready signal is 1 (high). In this case, the block captures parameters on the first cycle when the input valid signal is 1 (high).

Vector Input

This figure shows a sample output and latency of the OFDM Modulator block when you specify an eight-element column vector input, set the OFDM parameters source parameter to Property and use default settings for the other block parameters. FFT length is set to 64, Cyclic prefix length is set to 16, Insert DC null status is set to on, and Number of left guard subcarriers and Number of right guard subcarriers are set to 6 and 5, respectively.

In this example, the latency of the block is calculated using this formula: 2 x FFT length/vecLen + vecIFFTLatency + 22, where vecIFFTLatency is the latency of IFFT block for the specified FFT length and vector length, vecLen is the length of the vector, and 22 is the number of pipeline delays.

This calculation shows that the latency of the block is 105 clock cycles, as shown in this figure.

OFDM Modulator Block Latency for Vector Input Property

This figure shows a sample output and latency of the OFDM Modulator block when you specify an eight-element column vector input and set the OFDM parameters source parameter to Input port. For this example, FFTLen is set to 64, CPLen is set to 16, Insert DC null status is set to on, numLgSc and numRgSc are set to 6 and 5, respectively, and Maximum FFT length is set to 128.

In this example, the latency of the block is calculated using this formula: 2 x FFTLen/vecLen + vecIFFTLatency + floor((Maximum FFT length/FFTLen) * (vecLen – 1)/vecLen) + ceil(Maximum FFT length/vecLen) – (Maximum FFT length/FFTLen – 1) + 32, where vecIFFTLatency is the latency of IFFT block for the specified maximum FFT length and vector length, vecLen is the length of the vector, and 32 is the number of pipeline delays.

This calculation shows that the latency of the block is 161 clock cycles, as shown in this figure.

OFDM Modulator Block Latency for Vector Input Port

The block accepts input only when the ready signal is 1 (high). In this case, the block captures parameters on the first cycle when the input valid signal is 1 (high).

Performance

The performance of the synthesized HDL code varies with your target and synthesis options. The input data type used in this example for generating HDL code is fixdt(1,16,14).

This table shows the resource and performance data synthesis results when using the block with a default configuration for a scalar input and an eight-element column vector input. The generated HDL is targeted to the AMD^® Zynq^®- 7000 ZC706 evaluation board.

Input Data	Slice LUTs	Slice Registers	DSPs	Block RAMs	Maximum Frequency in MHz
Scalar	2227	3761	8	3	325.5
Vector	10967	19361	56	16	271.4

References

[1] 3GPP TS 36.211 version 14.2.0 Release 14. "Physical channels and modulation." LTE - Evolved Universal Terrestrial Radio Access (E-UTRA).

[2] "Wireless LAN Medium Access Control (MAC) and Physical layer (PHY) Specifications." IEEE Std 802.11 – 2012.

[3] Stefania Sesia, Issam Toufik, and Matthew baker. LTE - THE UMTS Long Term Evolution from theory to practice.

[4] Erik Dahlman, Stefan Parkvall, and Johan Skold. 4G - LTE/LTE - Advanced for Mobile broadband Second edition.

Extended Capabilities

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

This block supports C/C++ code generation for Simulink^® accelerator and rapid accelerator modes and for DPI component generation.

HDL Code Generation
Generate VHDL, Verilog and SystemVerilog code for FPGA and ASIC designs using HDL Coder™.

HDL Coder™ provides additional configuration options that affect HDL implementation and synthesized logic.

This block does not have any HDL Block Properties.

Version History

Introduced in R2020a

OFDM Modulator

Description

Examples

Modulate and Demodulate OFDM Streaming Samples

Ports

Input

data — Input data scalar | column vector

valid — Indicates valid input data scalar

FFTLen — Length of FFT scalar

Dependencies

CPLen — Length of cyclic prefix scalar

Dependencies

numLgSc — Number of left guard carriers of OFDM symbol scalar

Dependencies

numRgSc — Number of right guard carriers of OFDM symbol scalar

Dependencies

reset — Clear internal states scalar

Dependencies

winLen — Length of window scalar

Dependencies

Output

data — Modulated output data scalar | column vector

valid — Indicates valid output data scalar

ready — Indicates block is ready scalar

Parameters

Main

OFDM parameters source — Source of OFDM parameters Property (default) | Input port

Maximum FFT length — Maximum length of FFT length 64 (default) | power of 2 in range from 8 to 65,536

Dependencies

FFT length — Length of FFT 64 (default) | power of 2 in range from 8 to 65, 536

Dependencies

Cyclic prefix length — Length of cyclic prefix 16 (default) | integer in range from 0 to FFT length

Dependencies

Number of left guard subcarriers — Number of guard band subcarriers in left extreme of OFDM symbol 6 (default) | integer in range from 0 to (FFT length/2) – 1

Dependencies

Number of right guard subcarriers — Number of guard band subcarriers in right extreme of OFDM symbol 5 (default) | integer in range from 0 to (FFT length/2) – 1

Dependencies

Insert DC Null — Option to insert DC null on (default) | off

Enable reset input port — Reset signal off (default) | on

Windowing — Spectral growth reduction off (default) | on

Window length — Length of window 4 (default) | even integer in range from 1 to Cyclic prefix length

Dependencies

Maximum window length — Maximum length of window 8 (default) | integer in the range from 1 to CPLen

Dependencies

IFFT Parameters

Divide butterfly outputs by two — Divide FFT butterfly outputs by two on (default) | off

Rounding Method — Rounding mode for internal fixed-point calculations Floor (default) | Ceiling | Convergent | Nearest | Round | Zero

More About

Specifying Vector Input

Algorithms

Ready Generator

Symbol Formation

Sample Repeater

IFFT

Time-Domain FFT Shifter

Down Sampler

CP Addition

Windowing

Latency

Performance

References

Extended Capabilities

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

HDL Code Generation Generate VHDL, Verilog and SystemVerilog code for FPGA and ASIC designs using HDL Coder™.

Version History

See Also

Blocks

Objects

data — Input data
scalar | column vector

valid — Indicates valid input data
scalar

FFTLen — Length of FFT
scalar

CPLen — Length of cyclic prefix
scalar

numLgSc — Number of left guard carriers of OFDM symbol
scalar

numRgSc — Number of right guard carriers of OFDM symbol
scalar

reset — Clear internal states
scalar

winLen — Length of window
scalar

data — Modulated output data
scalar | column vector

valid — Indicates valid output data
scalar

ready — Indicates block is ready
scalar

OFDM parameters source — Source of OFDM parameters
`Property` (default) | `Input port`

Maximum FFT length — Maximum length of FFT length
`64` (default) | power of 2 in range from 8 to 65,536

FFT length — Length of FFT
`64` (default) | power of 2 in range from 8 to 65, 536

Cyclic prefix length — Length of cyclic prefix
`16` (default) | integer in range from 0 to FFT length

Number of left guard subcarriers — Number of guard band subcarriers in left extreme of OFDM symbol
`6` (default) | integer in range from 0 to (FFT length/2) – 1

Number of right guard subcarriers — Number of guard band subcarriers in right extreme of OFDM symbol
`5` (default) | integer in range from 0 to (FFT length/2) – 1

Insert DC Null — Option to insert DC null
`on` (default) | `off`

Enable reset input port — Reset signal
`off` (default) | `on`

Windowing — Spectral growth reduction
`off` (default) | `on`

Window length — Length of window
`4` (default) | even integer in range from 1 to Cyclic prefix length

Maximum window length — Maximum length of window
`8` (default) | integer in the range from 1 to CPLen

Divide butterfly outputs by two — Divide FFT butterfly outputs by two
`on` (default) | `off`

Rounding Method — Rounding mode for internal fixed-point calculations
`Floor` (default) | `Ceiling` | `Convergent` | `Nearest` | `Round` | `Zero`

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

HDL Code Generation
Generate VHDL, Verilog and SystemVerilog code for FPGA and ASIC designs using HDL Coder™.