# lteEPDCCHDMRS

EPDCCH demodulation reference signals

## Syntax

``sym = lteEPDCCHDMRS(enb,chs)``
``sym = lteEPDCCHDMRS(enb,chs,opts)``

## Description

example

````sym = lteEPDCCHDMRS(enb,chs)` returns the Enhanced Physical Downlink Control Channel Demodulation Reference Signal (EPDCCH DM-RS) symbols for transmission in a single subframe. By default the symbols are returned as a column vector. The order of the symbols is the same as the order that results when you use `lteEPDCCHDMRSIndices` to map them into an N-by-M-by-4 array. This array represents the resource element subframe grid across the four possible EPDCCH antenna ports (p = 107...110). The symbols are parameterized in terms of a configured PRB pair set which defines:the overall set of possible EPDCCH candidates and the aggregation of one or more consecutive enhanced control channel elements (ECCE). This aggregation identifies the specific EPDCCH instance that the DM-RS is associated with.The DM-RS symbols are created only for the specific PRB pairs and antenna ports that the corresponding EPDCCH is mapped to. For a localized EPDCCH transmission, the EPDCCH is associated with a single antenna port from p = 107...110, dependent on the `chs`.`RNTI` and ECCEs selected. Thus, the DM-RS antenna port symbols are output only for that single port. For a distributed transmission, the EPDCCH is mapped to two antenna ports in an alternating fashion. Therefore, the DM-RS symbols are generated for the PRBs in both ports: p = 107,109 for normal cyclic prefix and p = 107,108 for extended cyclic prefix. The output is ordered so that the symbols for the lowest antenna ports index come first. This order matches that of the DM-RS RE indices produced by `lteEPDCCHDMRSIndices`.```

example

````sym = lteEPDCCHDMRS(enb,chs,opts)` allows control of the format of the symbols through the options specified by `opts`. You can use this syntax to return the symbols as a numeric matrix, where each column contains symbols for an active antenna port.This function performs no precoding. If necessary, apply precoding externally.```

## Examples

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Specify the cell-wide settings and channel transmission configuration in parameter structures `enb` and `chs`.

```enb.NDLRB = 6; enb.NSubframe = 0; chs.EPDCCHECCE = [0 7]; chs.EPDCCHType = 'Localized'; chs.EPDCCHPRBSet = 2:3; chs.EPDCCHNID = 0; chs.RNTI = 1;```

Generate EPDCCH demodulation reference signal symbols.

`sym = lteEPDCCHDMRS(enb,chs)`
```sym = 12×1 complex 0.7071 - 0.7071i 0.7071 + 0.7071i 0.7071 + 0.7071i -0.7071 + 0.7071i 0.7071 - 0.7071i 0.7071 - 0.7071i 0.7071 + 0.7071i 0.7071 - 0.7071i 0.7071 + 0.7071i -0.7071 - 0.7071i ⋮ ```

Note: The warning messages generated simply advise you that default values are available and being used for uninitialized parameters. To suppress warnings for defaulted lte parameter settings, precede code with the following command: `lteWarning('off','DefaultValue')`

Specify the cell-wide settings and channel transmission configuration in parameter structures `enb` and `chs`.

```enb.NDLRB = 6; enb.NSubframe = 0; chs.EPDCCHECCE = [0,7]; chs.EPDCCHType = 'Distributed'; chs.EPDCCHPRBSet = 2:3; chs.EPDCCHNID = 0; chs.RNTI = 1;```

Generate DM-RS symbols for an EPDCCH having a distributed transmission. Return the symbols as a matrix, where each column contains symbols for an active antenna.

`sym = lteEPDCCHDMRS(enb,chs,'mat')`
```sym = 12×2 complex 0.7071 - 0.7071i 0.7071 - 0.7071i -0.7071 - 0.7071i -0.7071 - 0.7071i 0.7071 + 0.7071i 0.7071 + 0.7071i 0.7071 - 0.7071i 0.7071 - 0.7071i 0.7071 - 0.7071i 0.7071 - 0.7071i -0.7071 + 0.7071i -0.7071 + 0.7071i -0.7071 - 0.7071i -0.7071 - 0.7071i 0.7071 - 0.7071i 0.7071 - 0.7071i -0.7071 - 0.7071i -0.7071 - 0.7071i -0.7071 - 0.7071i -0.7071 - 0.7071i ⋮ ```

Note: The warning messages generated simply advise you that default values are available and being used for uninitialized parameters. To suppress warnings for defaulted lte parameter settings, precede code with the following command: `lteWarning('off','DefaultValue')`

## Input Arguments

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

Parameter FieldRequired or OptionalValuesDescription
`NDLRB`Required

Scalar integer from 6 to 110

Number of downlink resource blocks. (${N}_{\text{RB}}^{\text{DL}}$)

`CyclicPrefix`Optional

`'Normal'` (default), `'Extended'`

Cyclic prefix length

`NSubframe`Required

0 (default), nonnegative scalar integer

Subframe number

`DuplexMode`Optional

`'FDD'` (default), `'TDD'`

Duplexing mode, specified as one of the following:

• `'FDD'` — Frequency division duplex (default)

• `'TDD'` — Time division duplex

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

`TDDConfig`Optional

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

`SSC`Optional

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

Special subframe configuration (SSC)

Channel-specific transmission configuration, specified as a structure that can contain the following parameter fields.

Parameter FieldRequired or OptionalValuesDescription
`EPDCCHECCE`Required

1-element or 2-element vector specifying the 0-based ECCE index or inclusive [`begin`, `end`] ECCE index range according to the aggregation level `L` (```L = end – begin + 1```). The number of ECCEs in the candidate must be a power of 2.

If no transmission is required, leave this parameter empty.

The set of one or several consecutive ECCEs defining the EPDCCH transmission candidate in the overall EPDCCH set.

`EPDCCHType`Required

`'Localized'`, `'Distributed'`

EPDCCH transmission type

`EPDCCHPRBSet`Required

Vector of zero-based indices for the PRB pairs corresponding to the EPDCCH PRB set. The number of PRB pair indices must be a power of 2.

If no transmission is required, leave this parameter empty.

EPDCCH PRB pair indices

`EPDCCHNID`Required

Nonnegative scalar integer

EPDCCH nID parameter for scrambling sequence initialization

The following parameters apply when `EPDCCHType` is set to `'Localized'`.

`RNTI`Required

0 (default), scalar integer

Radio network temporary identifier (RNTI) value (16 bits)

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 the returned symbols, specified as one of the following:

• `'ind'` — returns the symbols as a column vector (default)

• `'mat'` — returns the symbols as a matrix in which each column contains symbols for an active antenna port from the set p = 107...110

Symbol format

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

Format of the returned symbols.

• `'rsonly'` — returns only active DM-RS symbols (default)

• `'rs+unused'` — also returns zeros for the RE locations, which should be unused because of EPDCCH DM-RS transmission on other EPDCCH antenna ports p = 107...110 that are not used by this EPDCCH transmission.

Example: `'ind rs+unused'`, `"ind rs+unused"`, `{'ind','rs+unused'}`, or `{"ind","rs+unused"}` specify the same formatting options.

Data Types: `char` | `string` | `cell`

## Output Arguments

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EPDCCH demodulation reference signal symbols, returned as a column vector containing the non-precoded DM-RS symbol sequences concatenated for all active PRB pairs and antenna ports. Optionally, the function returns `sym` as a numeric matrix, where each column contains symbols for an active antenna port.

Data Types: `double`

## Version History

Introduced in R2014b