# lteEPDCCHIndices

Enhanced physical downlink control channel (EPDCCH) resource element indices

## Syntax

``````[ind,info] = lteEPDCCHIndices(enb,chs)``````
``````[ind,info] = lteEPDCCHIndices(enb,chs,opts)``````

## Description

example

``````[ind,info] = lteEPDCCHIndices(enb,chs)``` returns the subframe resource element (RE) indices for the Enhanced Physical Downlink Control Channel (EPDCCH) and information related to EPDCCH indices, given the cell-wide settings structure, `enb`, and the EPDCCH transmission configuration, `chs`.```

example

``````[ind,info] = lteEPDCCHIndices(enb,chs,opts)``` formats the returned indices using options specified by `opts`.```

## Examples

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This example generates RE Indices of localized transmission in default and subscripted formats.

Specify the cell-wide settings in parameter structure, `enb`.

```enb.NDLRB = 6; enb.NSubframe = 0; enb.NCellID = 0; enb.CellRefP = 1; enb.CyclicPrefix = 'Normal'; enb.DuplexMode = 'FDD'; enb.NFrame = 0; enb.CSIRSPeriod = 'Off'; enb.ZeroPowerCSIRSPeriod = 'Off';```

Specify the channel transmission configuration in parameter structure, `chs`.

```chs.EPDCCHECCE = [0 7]; chs.EPDCCHType = 'Localized'; chs.EPDCCHPRBSet = 2:3; chs.EPDCCHStart = 2; chs.RNTI = 1;```

Generate 1-based linear resource element indices of a localized transmission.

```[ind,info] = lteEPDCCHIndices(enb,chs); size(ind)```
```ans = 1×2 228 1 ```

Display the size and the first 10 indices of `ind`.

`ind(1:10)`
```ans = 10x1 uint32 column vector 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 ```

Generate 1-based resource element indices in the subscript format [ `subcarrier`, `symbol`, `antenna` ].

```[ind,info] = lteEPDCCHIndices(enb,chs,'sub'); size(ind)```
```ans = 1×2 228 3 ```

Display the size and the first 10 indices of `ind`.

`ind(1:10,:)`
```ans = 10x3 uint32 matrix 25 3 2 26 3 2 27 3 2 28 3 2 29 3 2 30 3 2 31 3 2 32 3 2 33 3 2 34 3 2 ```

## 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. (${N}_{\text{RB}}^{\text{DL}}$)

`NCellID`Required

Integer from 0 to 503

Physical layer cell identity

`CyclicPrefix`Optional

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

Cyclic prefix length

`CellRefP`Required

1, 2, 4

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

`NSubframe`Required

0 (default), nonnegative scalar integer

Subframe number

The following parameter is only read when `chs.EPDCCHStart` is absent.

`CFI`Required

1, 2, or 3
Scalar or if the CFI varies per subframe, a vector of length 10 (corresponding to a frame).

Control format indicator (`CFI`) value. In TDD mode, `CFI` varies per subframe for the RMCs (`'R.0', 'R.5', 'R.6', 'R.6-27RB', 'R.12-9RB'`)

`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)

`NFrame`Optional

0 (default), nonnegative scalar integer

Frame number

`CSIRSPeriod`Optional

`'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.

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.

`CSIRSConfig`Required

Nonnegative scalar integer

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

`CSIRefP`Required

1 (default), 2, 4, 8

Array of number of CSI-RS antenna ports

`ZeroPowerCSIRSPeriod`Optional

`'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.

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 applicable if one or more of the above zero power subframe configurations are set to any value other than `'Off'`.

`ZeroPowerCSIRSConfig`Required

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.

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

Parameter FieldRequired or OptionalValuesDescription
`EPDCCHECCE`Required

1- or 2- element vector specifying the zero-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 of 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

`EPDCCHStart`Optional

integer from 0 to 4

If this parameter is not present, then the cell-wide CFI parameter is used for the starting symbol.

EPDCCH starting symbol

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

`RNTI`Required only for the `'Localized'` transmission type

0 (default), scalar integer

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

Index 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
Indexing style

`'ind'` (default), `'sub'`

Style for the returned indices, specified as one of the following options.

• `'ind'` — returns the indices in linear index form as a column vector (default)

• `'sub'` — returns the indices in `[subcarrier, symbol, antenna]` subscript row style. The number of rows in the output, `ind`, is the number of resource elements (NRE). Thus, `ind` is an NRE-by-3 matrix.

Index base

`'1based'` (default), `'0based'`

Base value of the returned indices. Specify `'1based'` to generate indices where the first value is 1. Specify `'0based'` to generate indices where the first value is 0.

Whether in linear or subscript format style, the indices are always formed out of `[subcarrier, symbol, antenna]` subscripts. These subscripts identify the used resource elements in each subframe resource grid per antenna port.

For the EPDCCH, the antenna subscripts have the possible range 1...4 (if index is one-based), which represents antenna ports p = 107...110. For a localized EPDCCH transmission, the antenna subscripts are a single value out of 1...4, dependent on the RNTI and ECCEs selected. For a distributed EPDCCH transmission, the antenna subscripts alternate between one of two values: {1,3} (p = 107,109) for normal cyclic prefix, and {1,2} (p = 107,108) for extended cyclic prefix. See TS 36.211 [1], Section 6.8A.5. Use these indices to index the subframe grid directly. The grid comprises the four possible EPDCCH antenna ports (p = 107...110) and is represented as an.NSC-by-NSYM-by-4 array.

Example: `'ind 1based'`, `"ind 1based"`, `{'ind','1based'}`, or `["ind","1based"]` specify the same formatting options.

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

## Output Arguments

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EPDCCH subframe resource element indices, returned by default in one-based linear indexing form as a numeric column vector of length NRE-by-1. NRE is the number of subframe resource elements. Optionally, for subscript-specific indexing style [`subcarrier`, `symbol`, `antenna`], `ind` is returned as a numeric matrix of size NRE-by-3. The grid comprises the four possible EPDCCH antenna ports (p = 107,...,110) and is represented as an NSC-by-NSYM-by-4 array. NSC is the number of subcarriers, NSYM is the number of symbols, and `4` is the number of antenna ports.

The indices are for a single transmission instance of the EPDCCH. The order of the indices is the same as required for the complex EPDCCH symbols mapping. Generate these symbols using `lteEPDCCH`. The indices are parameterized in terms of a configured PRB pair set that 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 within the set of EPDCCH candidates.

The EPDCCH can use either localized or distributed transmission, differing in the mapping of ECCEs to REs, active PRB pairs, and antenna ports.

Data Types: `double`

Dimensional information related to EPDCCH indices, returned as a scalar structure. The structure `info` contains the following fields.

Parameter FieldDescriptionValuesData Type
`EPDCCHG`

EPDCCH data bit capacity

Integerint32
`EPDCCHGd`

EPDCCH QPSK symbol capacity

Integerint32
`nEPDCCH`

Number of REs in a PRB pair configured for possible EPDCCH transmission. See TS 36.211. [1], Section 6.8A.1.

Integerint32
`NECCE`

Number of ECCE available for transmission of EPDCCHs in the PRB pair set

Integerint32
`NECCEPerPRB`

Number of ECCE per PRB pair

Integerint32
`NEREGPerECCE`

Number of EREG per ECCE

Integerint32
`EPDCCHPorts`

A vector indicating the set of antenna subscripts used by REs for this transmission instance of the EPDCCH. The subscripts are one-based (default) or zero-based as specified by `opts`.

Vector of integersint32

## 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.