ltePSCCHDRSIndices
PSCCH DM-RS resource element indices
Description
returns a column vector of PSCCH demodulation reference signal (DM-RS) resource
element indices for the specified UE settings structure. For more information, see
PSCCH Demodulation Reference Signal Indexing.ind
= ltePSCCHDRSIndices(ue
)
Examples
Create PSCCH DM-RS Values
Write the complex PSCCH DM-RS values into the PSCCH DM-RS resource elements in a PSCCH subframe for both D2D normal cyclic prefix and V2X. Display an image of their locations to compare both sidelink modes.
Create a user equipment settings structure and an empty resource grid subframe for 10 MHz bandwidth and D2D normal cyclic prefix. Assign a PRB set index of 5.
ue.NSLRB = 50;
ue.CyclicPrefixSL = 'Normal';
ue.NSLID = 1;
subframe_D2D = lteSLResourceGrid(ue);
ue.PRBSet = 5;
Generate PSCCH DM-RS indices and write PSCCH DM-RS values into subframe
.
pscchdrs_indices = ltePSCCHDRSIndices(ue); subframe_D2D(pscchdrs_indices) = ltePSCCHDRS();
Change user equipment settings to V2X sidelink mode. Assign a PRB set indices of 5 and 6.
ue.SidelinkMode = 'V2X';
subframe_V2X = lteSLResourceGrid(ue);
ue.PRBSet = [5 6]';
Generate PSCCH DM-RS indices and write PSCCH DM-RS values into subframe
.
pscchdrs_indices = ltePSCCHDRSIndices(ue); subframe_V2X(pscchdrs_indices) = ltePSCCHDRS(ue);
Display the PSCCH DM-RS locations for both sidelink modes.
subplot(2,1,1); imagesc(100*abs(subframe_D2D)) axis xy title('D2D'); subplot(2,1,2); imagesc(100*abs(subframe_V2X)); axis xy; title(ue.SidelinkMode)
Compare PSCCH DM-RS Resource Element Indexing
Compare PSCCH DM-RS resource element indexing formats.
Create a UE settings structure.
ue = struct('NSLRB',15,'CyclicPrefixSL','Normal','PRBSet',5);
One-based linear indexing, this is the default output style
Generate PSCCH DM-RS indices, using the default one-based linear indexing style.
ind1 = ltePSCCHDRSIndices(ue); ind1(1)
ans = uint32
601
Zero-based linear indexing
Generate PSCCH DM-RS indices, using zero-based linear indexing style.
opts = '0based';
ind0 = ltePSCCHDRSIndices(ue,opts);
ind0(1)
ans = uint32
600
For zero-based indexing, the first assigned index is one lower than the one-based indexing.
One-based indexing in [subcarrier,symbol,port]
subscript row style
Generate PSCCH DM-RS indices, one-based subscript row style.
opts = {'sub','1based'}; ind1sub = ltePSCCHDRSIndices(ue,opts); size(ind1sub)
ans = 1×2
24 3
ind1sub(1,:)
ans = 1x3 uint32 row vector
61 4 1
The subscript row style outputs a 24-by-3 matrix. Viewing the first row you can see symbol number 4 is occupied.
Two PSCCH subframe symbols are reserved for transmission of the PSCCH DM-RS. Inspecting the output matrix for unique symbol values, shows that the PSCCH DM-RS occupy symbols 4 and 11 for one-based indexing.
unique(ind1sub(:,2,:))
ans = 2x1 uint32 column vector
4
11
Input Arguments
ue
— User equipment settings
structure
User equipment settings, specified as a parameter structure containing these fields:
SidelinkMode
— Sidelink mode
'D2D'
(default) | 'V2X'
| optional
Sidelink mode, specified as 'D2D'
or
'V2X'
.
Data Types: char
| string
NSLRB
— Number of sidelink resource blocks
integer scalar from 6 to 110
Number of sidelink resource blocks, specified as an integer scalar from 6 to 110.
Example: 6
, which corresponds to a channel
bandwidth of 1.4 MHz.
Data Types: double
CyclicPrefixSL
— Cyclic prefix length
'Normal'
(default) | 'Extended'
| optional
Cyclic prefix length, specified as 'Normal'
or 'Extended'
.
Data Types: char
| string
PRBSet
— Zero-based physical resource block index
integer | integer column vector | two-column integer matrix
Zero-based physical resource block (PRB) index, specified as an integer, an integer column vector, or a two-column integer matrix.
For D2D sidelink, the PSCCH is intended to be transmitted in a single PRB in a subframe and
therefore, specifying PRBSet
as a scalar PRB index is recommended.
For V2X sidelink, the PSCCH is intended to be transmitted in a pair of consecutive PRB
in a subframe, therefore PRBSet
must be a column vector containing
two consecutive indices. However, for a more general nonstandard multi-PRB allocation,
PRBSet
can be a set of indices specified as an integer column
vector or as a two-column integer matrix corresponding to slot-wise resource allocations
for PSCCH.
Data Types: double
Data Types: struct
opts
— Output format options for resource element indices
character vector | cell array of character vectors | string array
Output format options for resource element indices, specified as a character vector, cell
array of character vectors, or string array. For convenience, you can
specify several options as a single character vector or string scalar by a
space-separated list of values placed inside the quotes. Values for
opts
when specified as a character vector include
(use double quotes for string) :
Category | Options | Description |
---|---|---|
Indexing style |
| The returned indices are in linear index style. |
| The returned indices are in | |
Index base |
| The returned indices are one-based. |
| The returned indices are zero-based. |
Example: 'ind 1based'
, "ind 1based"
,
{'ind','1based'}
, or ["ind","1based"]
specify
the same formatting options.
Data Types: char
| string
| cell
Output Arguments
ind
— PSCCH DM-RS resource element indices
integer column vector | three-column integer matrix
PSCCH DM-RS resource element indices, returned as an integer column vector or a three-column
integer matrix. For D2D sidelink, the returned vector or matrix has 24 PSCCH
DM-RS resource element indices. For a V2X configured PSCCH,
ind
is a 96-by-1 vector with indices of the
resource elements in the four DRS symbols in a subframe. For more
information, see PSCCH Demodulation Reference Signal Indexing.
Data Types: uint32
More About
PSCCH Demodulation Reference Signal Indexing
Use the indexing function, ltePSCCHDRSIndices
, and the corresponding
sequence function, ltePSCCHDRS
,
to populate the resource grid for any PSCCH subframe. The PSCCH DM-RS
is transmitted in the available SC-FDMA symbols in a PSCCH subframe,
using a single layer on antenna port 1000.
The indices are ordered as the PSCCH DM-RS QPSK modulation symbols
should be, applying frequency-first mapping. One-based linear indexing
is the default return format but you can also generate alternative
indexing formats by using the opts
input.
The resource elements in the last SC-FDMA symbol within a subframe are counted in the mapping process but should not be transmitted. The sidelink-specific SC-FDMA modulation creates the last symbol, which serves as a guard symbol.
For D2D sidelink, in zero-based indexing, the SC-FDMA symbol indices used are {3,10} for
normal cyclic prefix and {2,8} for extended cyclic prefix. The same symbols are used by the
ltePUSCHDRSIndices
function. For V2X sidelink, there are four DM-RS SC-FDMA
symbols with indices {2,5,8,11}, defined for normal cyclic prefix only.
Note
The indicated symbol indices are based on TS 36.211, Section 9.8. However to align with the LTE Toolbox™ subframe orientation, these indices are expanded from symbol index per slot to symbol index per subframe.
For more information on mapping symbols to the resource element grid, see Resource Grid Indexing.
PSCCH Demodulation Reference Signal
The PSCCH demodulation reference signal (DM-RS) sequence is transmitted
alongside the ltePSCCH
values using the two SC-FDMA symbols
allocated to DM-RS in a PSCCH subframe. By default, the output vector is the repetition of
a 12-element sequence and specified in TS 36.211, Section 9.8. The output vector is mapped
onto the 12 subcarriers of the DM-RS SC-FDMA symbol in each slot of the single PSCCH
physical resource block (PRB) transmission on antenna port 1000. For a V2X configured PSCCH,
the output will be a 96-by-1 vector to be mapped onto the 24 subcarriers in each of the pair
of DRS SC-FDMA symbols per slot for two consecutive resource blocks.
The single-PRB PSCCH DM-RS is transmitted using a short base
QPSK reference sequence instead of the Zadoff-Chu sequence that is
normally used for reference signals. Because the Zadoff-Chu sequence
is not used, the RootSeq
and NZC
fields
are set to –1 in the info
structure returned
by ltePSCCHDRS
.
References
[1] 3GPP TS 36.211. “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation.” 3rd Generation Partnership Project; Technical Specification Group Radio Access Network. URL: https://www.3gpp.org.
Version History
Introduced in R2016b
See Also
MATLAB Command
You clicked a link that corresponds to this MATLAB command:
Run the command by entering it in the MATLAB Command Window. Web browsers do not support MATLAB commands.
Select a Web Site
Choose a web site to get translated content where available and see local events and offers. Based on your location, we recommend that you select: .
You can also select a web site from the following list:
How to Get Best Site Performance
Select the China site (in Chinese or English) for best site performance. Other MathWorks country sites are not optimized for visits from your location.
Americas
- América Latina (Español)
- Canada (English)
- United States (English)
Europe
- Belgium (English)
- Denmark (English)
- Deutschland (Deutsch)
- España (Español)
- Finland (English)
- France (Français)
- Ireland (English)
- Italia (Italiano)
- Luxembourg (English)
- Netherlands (English)
- Norway (English)
- Österreich (Deutsch)
- Portugal (English)
- Sweden (English)
- Switzerland
- United Kingdom (English)