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lteCSIRS

Channel state information reference signal

Description

sym = lteCSIRS(enb) returns the channel state information reference signal (CSI-RS) symbols for transmission in a single subframe on up to eight antenna ports (p = 15,...,22). See lteCSIRS Processing.

sym = lteCSIRS(enb,opts) formats the returned symbols using options specified by opts.

example

Examples

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Generate CSI-RS symbols and combine them with a 10 MHz, release 8, port 0 PDSCH subframe resource grid.

Initialize a reference channel structure. Create a 10 MHz, release 8, port 0 PDSCH configuration parameter structure. Set subframe number to 1, number of CSI-RS antenna ports to 8, CSI-RS configuration to 0, and CSIRSPeriod to 6.

rmc = lteRMCDL('R.2','FDD',1);
rmc.NSubframe = 1;
rmc.CSIRefP = 8;
rmc.CSIRSConfig = 0;
rmc.CSIRSPeriod = 6;

The 8 antenna ports are ports 15 to 22. The setting for CSIRSPeriod is Icsi-rs, which equals [ Tcsi-rs Dcsi-rs]=[10 1].

Create a 3-D resource grid to contain the subframes for all eight CSI-RS ports.

rgrid = lteResourceGrid(rmc,rmc.CSIRefP);

Write the release 8 port 0 transmission into the first plane of the resource grid.

[wave,rgrid(:,:,1)] = lteRMCDLTool(rmc,[1,0,0,1]);

Create the CSI-RS symbols for ports 15 to 22. Overwrite all ports included in the port 0 transmission with the actual CSI-RS and unused RE.

rgrid(lteCSIRSIndices(rmc,'rs+unused')) = lteCSIRS(rmc,'rs+unused');

Input Arguments

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eNodeB cell-wide settings, specified as a structure containing these parameter fields:

Parameter FieldRequired or OptionalValuesDescription
NDLRBRequired

Scalar integer from 6 to 110

Number of downlink resource blocks (NRBDL)

NCellIDRequired

Integer from 0 to 503

Physical layer cell identity

NSubframeRequired

0 (default), nonnegative scalar integer

Subframe number

NFrameOptional

0 (default), nonnegative scalar integer

Frame number

CellRefP is only used when the Indexing format option for indexing generation is'rs+unused'
  CellRefPOptional

1 (default), 2, 4

Number of cell-specific reference signal (CRS) antenna ports

CyclicPrefixOptional

'Normal' (default), 'Extended'

Cyclic prefix length

DuplexModeOptional

'FDD' (default), 'TDD'

Duplexing mode, specified as either:

  • 'FDD' for Frequency Division Duplex

  • 'TDD' for Time Division Duplex

The following parameters apply when DuplexMode is set to 'TDD'.

  TDDConfigOptional

0, 1 (default), 2, 3, 4, 5, 6

Uplink–downlink configuration

  SSCOptional

0 (default), 1, 2, 3, 4, 5, 6, 7, 8, 9

Special subframe configuration (SSC)

CSIRSPeriodOptional

'On' (default), 'Off', Icsi-rs (0,...,154), [Tcsi-rs Dcsi-rs]. You can also specify values in a cell array of configurations for each resource.

See note.

CSI-RS subframe configurations for one or more CSI-RS resources. Multiple CSI-RS resources can be configured from a single common subframe configuration or from a cell array of configurations for each resource.

The following CSI-RS resource parameters apply only when CSIRSPeriod sets one, or more CSI-RS subframe configurations to any value other than 'Off'. Each parameter length must be equal to the number of CSI-RS resources required.

  CSIRSConfigRequired

Nonnegative scalar integer

Array CSI-RS configuration indices. See TS 36.211, Table 6.10.5.2-1.

  CSIRefPRequired

1 (default), 2, 4, 8

Array of number of CSI-RS antenna ports

  NCSIIDOptional

Nonnegative scalar integer

CSI-RS scrambling identity. If this field is not present, then NCellID is used as the identity.

ZeroPowerCSIRSPeriodOptional

'Off' (default), 'On', Icsi-rs (0,...,154), [Tcsi-rs Dcsi-rs]. You can also specify values in a cell array of configurations for each resource.

See note.

Zero power CSI-RS subframe configurations for one or more zero power CSI-RS resource configuration index lists. Multiple zero power CSI-RS resource lists can be configured from a single common subframe configuration or from a cell array of configurations for each resource list.

The following zero power CSI-RS resource parameter is only required if one, or more of the above zero power subframe configurations are set to any value other than 'Off'.

  ZeroPowerCSIRSConfigRequired

16-bit bitmap character vector or string scalar (truncated if not 16 bits or '0' MSB extended), or a numeric list of CSI-RS configuration indices. You can also specify values in a cell array of configurations for each resource.

Zero power CSI-RS resource configuration index lists (TS 36.211 Section 6.10.5.2). Specify each list as a 16-bit bitmap character vector or string scalar (if less than 16 bits, then '0' MSB extended), or as a numeric list of CSI-RS configuration indices from TS 36.211 Table 6.10.5.2-1 in the '4' CSI reference signal column. Multiple lists can be defined using a cell array of individual lists.

[1]

Note:

  1. CSIRSPeriod and ZeroPowerCSIRSPeriod parameters control the downlink subframes in which the different CSI-RS resources are present. Valid settings include:

    • always 'On'

    • always 'Off'

    • scalar subframe configuration index Icsi-rs from 0 through 154

    • explicit subframe periodicity and offset pair [Tcsi-rs Dcsi-rs]

    The subframes containing CSI-RS are located with NSubframe and the optional NFrame parameters. NSubframe can be greater than 10; thus NSubframe = 11 is equivalent to setting NSubframe to 1 and NFrame to 1.

    For more information, see TS 36.211 [1], Section 6.10.5.3.

Symbol generation options, 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):

OptionValuesDescription
Symbol style

'ind' (default), 'mat'

Style for returning CSI-RS symbols, specified as one of the following options.

  • 'ind' — returns the CSI-RS symbols as a column vector (default)

  • 'mat' — returns the CSI-RS symbols as a matrix, where each column contains symbols for an individual port and CSI-RS configuration. To form a matrix, a column can contain duplicate entries.

Symbol format

'rsonly' (default), 'rs+unused'

Format for the returned symbols, specified as one of the following options.

  • 'rsonly' — returns only defined CSI-RS symbols (default), both zero and non-zero

  • 'rs+unused' — also includes zeros for the resource element (RE) locations that should be unused because they are reserved for CSI-RS on another port.

Note

Returned symbols specify the CSI-RS resource values within an N-by-M-by-antennas array. The number of antennas is max(CSIRefP) or if zero power CSI-RS are also defined number of antennas is max(max(CSIRefP),4). For the 'rs+unused' option, the number of antennas used to define the empty REs (either because they are zero power or they are unused in another port) is max(max(CSIRefP),CellRefP).

Example: 'ind rsonly', "ind rsonly", {'ind','rsonly'}, or ["ind","rsonly"] specify the same formatting options.

Data Types: char | string | cell

Output Arguments

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CSI-RS symbols for transmission in a single subframe on up to eight antenna ports, returned as a column vector or matrix of concatenated CSI-RS symbol sequences for each of the enb.CSIRefP ports based on the cell-wide parameter settings. The length of sym is the number of resource elements. See lteCSIRS Processing.

Data Types: double
Complex Number Support: Yes

More About

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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 R2014a