Main Content

ltePBCH

Physical broadcast channel

collapse all in page

Syntax

sym = ltePBCH(enb,cw)

Description

sym = ltePBCH(enb,cw) returns a matrix containing the complex symbols of the Physical Broadcast Channel (PBCH) for cell-wide settings structure enb and codeword cw. The function performs all physical channel processing steps, including scrambling, QPSK modulation, layer mapping, and precoding as defined in TS 36.211 [1], Section 6.6.

The BCH transport channel consumes information bits every 40 ms. The coded transport block is then passed to PBCH for physical channel processing. The PBCH is transmitted in the first subframe of every frame, so four successive frames are required to transmit one transport block. As the scrambling sequence is initialized at the boundary of every 40 ms, this function expects 40 ms worth of data. For example, it expects 1920 bits for normal cyclic prefix, or 1728 bits for extended cyclic prefix. Demultiplex the output of this function into quarter length blocks for transmission on the first subframe in each 10 ms frame.

Note

When you are using this function together with the ltePBCHIndices function, you must account for the fact that one transport block is transmitted over four frames. See the Create Resource Grid Containing PBCH Symbols example for details.

example

Examples

collapse all

Open Live Script

Generate physical broadcast channel (PBCH) symbols using the MIB.

Create cell-wide configuration structure initialized to RMC R.0. Generate the MIB. Pass the MIB through broadcast channel (BCH) transport channel coding.

enb = lteRMCDL('R.0');
mib = lteMIB(enb);
bchCoded = lteBCH(enb,mib);

Generate and display the PBCH symbols.

pbchSymbols = ltePBCH(enb,bchCoded);
pbchSymbols(1:10)
ans = 10×1 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
Open Live Script

Create a cell-wide configuration structure initialized to RMC R.0. Generate the MIB. Pass the MIB through BCH transport channel coding.

enb = lteRMCDL("R.0");
mib = lteMIB(enb);
bchCoded = lteBCH(enb,mib);

Generate the PBCH symbols and their indices.

pbchSymbols = ltePBCH(enb,bchCoded);
pbchIndices = ltePBCHIndices(enb,{'1based'});

Isolate the number of PBCH symbols.

numPBCHSymbols = size(pbchIndices,1);

Populate a four-frame resource grid containing the entire PBCH transmission.

grid = [];
for frameIndex = 0:3
    gridTmp = lteResourceGrid(enb);
    startIdx = mod(frameIndex,4) * numPBCHSymbols + 1;
    endIdx = (mod(frameIndex,4) + 1) * numPBCHSymbols;
    gridTmp(pbchIndices) = pbchSymbols(startIdx:endIdx,:);
    grid = [grid gridTmp];
end

Input Arguments

collapse all

Cell-wide settings, specified as a structure. enb must contain the following fields.

Physical layer cell identity, specified as a scalar integer.

Data Types: double

Number of cell-specific reference signal antenna ports, specified as 1, 2, or 4.

Data Types: double

Data Types: struct

PBCH codeword, specified as a vector. cw contains the bit values of the PBCH codeword for modulation.

Data Types: double | single | uint8 | uint16 | uint32 | uint64 | int8 | int16 | int32 | int64

Output Arguments

collapse all

PBCH symbols, returned as a numeric matrix. sym contains the complex symbols of the Physical Broadcast Channel (PBCH) for cell-wide settings, enb, and codeword, cw. Its size is N-by-CellRefP, where N is the number of modulation symbols for one antenna port and CellRefP is the number of antenna ports.

Data Types: double
Complex Number Support: Yes

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.

[2] 3GPP TS 36.101. “Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) Radio Transmission and Reception.” 3rd Generation Partnership Project; Technical Specification Group Radio Access Network. URL: https://www.3gpp.org.

Version History

Introduced in R2014a

See Also

| | |