ltePSBCHDRS

PSBCH demodulation reference signal

Syntax

[seq,info] = ltePSBCHDRS(ue)

Description

[seq,info] = ltePSBCHDRS(ue) returns a 144-by-1 complex column vector sequence containing PSBCH demodulation reference signal (DM-RS) values and an associated information structure for the specified UE settings structure. For more information, see PSBCH Demodulation Reference Signal.

Examples

Generate PSBCH DM-RS Sequence

Generate a PSBCH DM-RS sequence associated with both DM-RS SC-FDMA symbols in a subframe.

ue.NSLID = 170;
[psbchdrs_seq,info] = ltePSBCHDRS(ue);

Plot the DM-RS sequence (real vs. imaginary).

plot(psbchdrs_seq,'o')

Input Arguments

ue — User equipment settings

structure

User equipment settings, specified as a parameter structure containing this field:

SidelinkMode — Sidelink mode

'D2D' (default) | 'V2X' | optional

Sidelink mode, specified as 'D2D' or 'V2X'.

Data Types: char | string

NSLID — Physical layer sidelink synchronization identity

integer from 0 to 355

Physical layer sidelink synchronization identity, specified as an integer from 0 to 355. ($$N_{\text{ID}}^{\text{SL}}$$)

Data Types: double

Data Types: struct

Output Arguments

seq — PSBCH DM-RS values

column vector

PSBCH DM-RS values, returned as a column vector. For the D2D sidelink mode, seq is a 144-length column containing the values for each DM-RS symbol in each slot in a subframe. For V2X, it is a 216-by-1 complex column containing the concatenated values for the three DM- RS symbols in a subframe.

Data Types: double
Complex Number Support: Yes

info — PSBCH DM-RS information

structure

PSBCH DM-RS information about the intermediate variables used to create the DM-RS, returned as a parameter structure containing these fields:

Alpha — Reference signal cyclic shift for each slot

two-column vector

Reference signal cyclic shift for each slot, returned as a two-column vector. (α)

Alpha is proportional to NCS, where $$\alpha =\frac{2\pi n_{cs,\lambda }}{12}$$.

SeqGroup — Base sequence group number for each slot

two-column vector

Base sequence group number for each slot, returned as a two-column vector. (u)

SeqIdx — Base sequence number for each slot

two-column vector

Base sequence number for each slot, returned as a two-column vector. (v)

RootSeq — Root Zadoff-Chu sequence index for each slot

two-column vector

Root Zadoff-Chu sequence index for each slot, returned as a two-column vector. (q)

NCS — Cyclic shift values for each slot

two-column vector

Cyclic shift values for each slot, returned as a two-column vector. ($$n_{\text{cs,}\lambda }$$)

NZC — Zadoff-Chu sequence length

integer

Zadoff-Chu sequence length, returned as an integer. ($$N_{ZC}^{RS}$$)

OrthSeq — Orthogonal cover value for each slot

matrix

Orthogonal cover value for each slot, returned as a matrix. ($$\overline{w}$$)

Data Types: struct

More About

PSBCH Demodulation Reference Signal

The PSBCH demodulation reference signal (DM-RS) is transmitted alongside the ltePSBCH values in the central 72 resource elements and in two SC-FDMA symbols in a synchronization subframe for D2D sidelink mode and three SC-FDMA symbols for V2X.. For zero-based indexing, the SC-FDMA symbol indices are {3,10} for normal cyclic prefix and {2,8} for extended cyclic prefix. These are the same symbols used by the PUSCH DM-RS, see ltePUSCHDRSIndices. For the V2X sidelink mode, the symbol indices are {4,6,9}.

Note

The indicated symbol indices are based on TS 36.211, Section 9.8, but expanded from symbol index per slot to symbol index per subframe to align with the LTE Toolbox™ subframe orientation. For more information on mapping symbols to the resource element grid, see Resource Grid Indexing.

PSBCH Demodulation Reference Signal Indexing

Use the indexing function, ltePSBCHDRSIndices, and the corresponding sequence function, ltePSBCHDRS, to index the resource grid for any synchronization subframe number. The indices are ordered as the PSBCH DM-RS symbols should be, applying frequency-first mapping, into the two DM-RS SC-FDMA symbols. 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.

Version History

Introduced in R2016b