[waveform,info] = lteSCFDMAModulate(ue,grid)
[waveform,info] = lteSCFDMAModulate(ue,grid,windowing)
IFFT calculation, half-subcarrier shifting, and cyclic prefix insertions.
It optionally performs raised-cosine windowing and overlapping of
adjacent SC-FDMA symbols of the complex symbols in the resource array,
For a block diagram that illustrates the steps in SC-FDMA modulation, see Algorithms.
Perform SC-FDMA modulation of one subframe of random uniformly-distributed noise, using a 10MHz configuration.
ue = struct('NULRB',50); dims = lteULResourceGridSize(ue); reGrid = reshape(lteSymbolModulate(randi([0,1],prod(dims)*2,1), ... 'QPSK'),dims); waveform = lteSCFDMAModulate(ue,reGrid);
ue— UE-specific settings
UE-specific settings, specified as a structure.
the following fields.
|Parameter Field||Required or Optional||Values||Description|
Scalar integer from 6 to 110
Number of uplink resource blocks. ()
Cyclic prefix length
Nonnegative scalar integer
Default value is absent.
The number of time-domain samples over which windowing and overlapping of SC-FDMA symbols is appliedSee Note
The number of samples used for windowing depends on the cyclic prefix length (normal or extended) and the number of resource blocks, and is chosen in accordance with the maximum values implied in TS 36.104, Tables E.5.1-1 and E.5.1-2 . The number of windowing samples is a compromise between the effective duration of cyclic prefix (and therefore the channel delay spread tolerance) and the spectral characteristics of the transmitted signal (not considering any additional FIR filtering). For a larger amount of windowing, the effective duration of the cyclic prefix is reduced but the transmitted signal spectrum has smaller out of band emissions.
grid— Resource grid
Resource grid, specified as an M-by-N-by-P numeric
array array. The grid input contains M number of
subcarriers, N number of SC-FDMA symbols, and P number
of transmission antennas. The array contains resource elements (REs)
for a number of subframes across all configured antenna ports, as
described in Data Structures.
Alternatively, it contains multiple such matrices concatenated to
give multiple subframes (concatenation across the columns or 2nd dimension).
The antenna planes in
grid are each OFDM modulated
to give the columns of
Dimension M must be 12 ×
NULRB must be an integer from 6 to 110. Dimension N must
be a multiple number of symbols in a subframe L,
where L=14 for normal cyclic prefix and L=12
for extended cyclic prefix. Dimension P must be
grid can span multiple subframes and
windowing and overlapping is applied between all adjacent SC-FDMA
symbols, including the last of one subframe and the first of the next.
Therefore a different result is obtained than if
called on individual subframes and then those time-domain waveforms
concatenated. The resulting waveform in that case would have discontinuities
at the start/end of each subframe. Therefore it is recommended that
all subframes for SC-FDMA modulation first be concatenated before
lteSCFDMAModulate on the resulting multi-subframe
array. However, individual subframes can be OFDM modulated and the
resulting multi-subframe time-domain waveform created by manually
Complex Number Support: Yes
windowing— Number of windowed and overlapped samples
Number of windowed and overlapped samples, specified as a positive
scalar integer. This argument controls the number of windowed and
overlapped samples used in time-domain windowing. If present, it is
used for the SC-FMDA modulation (instead of
and it is the value output for
waveform— SC-FDMA modulated waveform
SC-FDMA modulated waveform, returned as a numeric matrix of
size T-by-P, where T is
the number of time-domain samples and P is the
number of transmission antennas. where Nfft is
the IFFT size and K is the number of subframes
in the input
grid. Nfft is
a function of the Number of Resource Blocks (NRB).
In general, Nfft is
the smallest power of 2 greater than or equal to
It is the smallest FFT that spans all subcarriers and results in a
bandwidth occupancy (12×NRB/Nfft)
of no more than 85%.
Complex Number Support: Yes
info— Information about SC-FDMA modulated waveform
Information about SC-FDMA modulated waveform, returned as a
info contains the following
SamplingRate— Sampling rate of time-domain waveform
Sampling rate of time-domain waveform,
returned as a positive numeric scalar. The sampling rate of the waveform
is given by the equation: SamplingRate = 30.72
MHz / 2048 × NFFT.
Nfft— Number of FFT points
Number of FFT points, returned as a positive scalar integer.
Windowing— Number of time-domain samples over which windowing and overlapping of SC-FDMA symbols is applied
Number of time-domain samples over which windowing and overlapping of SC-FDMA symbols is applied, returned as a positive scalar integer.
CyclicPrefixLengths— Cyclic prefix length
Cyclic prefix length (in samples) of each OFDM symbol in a subframe.
|for ||for |
|2048||[160 144 144 144 144 144 144 160 144 144 144 144 144 144]||[512 512 512 512 512 512 512 512 512 512 512 512]|
|1024||[80 72 72 72 72 72 72 80 72 72 72 72 72 72]||[256 256 256 256 256 256 256 256 256 256 256 256]|
|512||[40 36 36 36 36 36 36 40 36 36 36 36 36 36]||[128 128 128 128 128 128 128 128 128 128 128 128]|
|256||[20 18 18 18 18 18 18 20 18 18 18 18 18 18]||[64 64 64 64 64 64 64 64 64 64 64 64]|
|128||[10 9 9 9 9 9 9 10 9 9 9 9 9 9]||[32 32 32 32 32 32 32 32 32 32 32 32]|
As shown in this table, for
The following diagram illustrates the processing performed by SC-FDMA modulation.
 3GPP TS 36.104. "Base Station (BS) radio transmission and reception." 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA). URL: http://www.3gpp.org.