# ltePSSS

Primary sidelink synchronization signal

## Syntax

``s = ltePSSS(ue)``

## Description

example

````s = ltePSSS(ue)` returns a 124-by-1 complex column vector containing the primary sidelink synchronization signal (PSSS) values for user equipment settings in the `ue` structure. For more information, see Primary Sidelink Synchronization Signal.```

## Examples

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Generate PSSS values for in-coverage and out-of-coverage identities.

```psss_net = ltePSSS(struct('NSLID',0)); psss_oon = ltePSSS(struct('NSLID',168));```

Plot the returned synchronization signal for the in-coverage identities (blue, +) and the out-of-coverage identities (red, o).

```scatPlot = scatterplot(psss_net,1,0,'b+'); grid hold on scatterplot(psss_oon,1,0,'ro',scatPlot)```

## Input Arguments

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UE-specific settings, specified as a structure containing this parameter field:

Physical layer sidelink synchronization identity, specified as an integer from 0 to 335. (${N}_{\text{ID}}^{\text{SL}}$)

Example: 6

Data Types: `double`

## Output Arguments

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PSSS values, returned as a 124-by-1 complex-valued numeric column vector. These values are created for the user equipment settings in the `ue` structure. For more information, see Primary Sidelink Synchronization Signal.

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### Primary Sidelink Synchronization Signal

The primary sidelink synchronization signal (PSSS) is transmitted in the central 62 resource elements of two adjacent SC-FDMA symbols in a synchronization subframe. The same sequence of 62 complex values is repeated in each of the symbols, resulting in a 124-by-1 element vector returned by the `ltePSSS` function. The values of this sequence are ordered as they should be mapped into the resource elements of the adjacent symbols using `ltePSSSIndices`. If a terminal is transmitting PSSS, then the PSSS should be sent every 40 ms with the exact subframe dependent on the RRC signaled subframe number offset (syncOffsetIndicator-r12).

The PSSS is sent on antenna port 1020, along with the secondary sidelink synchronization signal (SSSS). A synchronization subframe also contains the PSBCH, which is sent on antenna port 1010. The transmission power of the PSSS symbols should be the same as the PSBCH therefore they should be scaled by $\sqrt{72}{62}}$ in a subframe. No PSCCH or PSSCH transmission will occur in a sidelink subframe configured for synchronization purposes.

As specified in TS 36.211, Section 9.7, the PSSS identity assignment depends on the network coverage. The set of all ${N}_{\text{ID}}^{\text{SL}}$ is divided into two sets, id_net {0, ..., 167} and id_oon {168, ..., 335}, which are used by terminals that are in-network and out-of-network coverage, respectively. The sidelink physical layer cell identity number, ${N}_{\text{ID}}^{\text{SL}}$, corresponds to the `ltePSSS` input UE settings structure field `ue`.`NSLID`. Within each set, all identities result in the same PSSS. For an in-network terminal, the `ue`.`NSLID` value corresponds to the RRC sidelink synchronization signal identity (slssid-r12) associated with the cell.

### Primary Sidelink Synchronization Signal Indexing

Use the indexing function, `ltePSSSIndices`, and the corresponding sequence function, `ltePSSS`, to populate the resource grid for the desired subframe number. The PSSS values are output by `ltePSSS`, ordered as they should be mapped, applying frequency-first mapping into the resource elements of the adjacent symbols using `ltePSSSIndices`. When indexing is zero-based, the SC-FDMA symbols used are {1,2} for normal cyclic prefix and {0, 1} for extended cyclic prefix.

Note

The indicated symbol indices are based on TS 36.211, Section 9.7. 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.

## 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.