Sidelink SC-FDMA modulation information
Calculate the sampling rate of a 5 MHz sidelink waveform after sidelink SC-FDMA modulation.
Create a UE settings structure. Specify 25 resource blocks, which corresponds to 5 MHz channel bandwidth.
ue = struct('NSLRB',25);
For the specified channel bandwidth, find the sidelink SC-FDMA modulation sampling rate.
slscfdmaInfo = lteSLSCFDMAInfo(ue); samplingRate = slscfdmaInfo.SamplingRate
samplingRate = 7680000
ue— User equipment settings
User equipment settings, specified as a parameter structure containing these fields:
The sidelink SC-FDMA modulation processing
IFFT calculation, half-subcarrier shifting, cyclic prefix insertions,
and optional raised-cosine windowing and overlapping of adjacent sidelink
SC-FDMA symbols. TS 36.211 specifies that for PSSCH (Section 9.3.6),
PSCCH (9.4.6), PSDCH (9.5.6) and PSBCH (9.6.6), resource elements
in the last SC-FDMA symbol within a subframe should be counted in
the mapping process but not transmitted. Therefore, before performing
the IFFT, the last SC-FDMA symbol of each subframe in the input resource
grid is set to zero.
For sidelink SC-FDMA modulation, calling
a multi-subframe array of resource grids is recommended.
When the resource element grid input to
lteSLSCFDMAModulate spans multiple subframes,
the windowing and overlapping is applied between all adjacent SC-FDMA
symbols, including the last symbol of the previous subframe and the
first symbol of the next subframe. Multi-subframe modulation processing
results in a waveform that does not have discontinuities between subframes.
A time-domain waveform that concatenates individually modulated subframes has discontinuities at the start and end of each subframe. To avoid these discontinuities, the resulting multi-subframe time-domain waveform must be created by manually overlapping symbols at the subframe boundaries.
If the value for windowing is zero, issues concerning concatenation of subframes before sidelink SC-FDMA modulation do not apply.
Windowing is absent,
Windowing returns a default value chosen
as a function of NRB. The chosen value is a compromise between:
The effective duration of cyclic prefix, and therefore the channel delay spread tolerance
The spectral characteristics of the transmitted signal, not considering any additional FIR filtering