lteBCH

Broadcast channel

Syntax

codeblk = lteBCH(enb,trblk)

codeblk = lteBCH(trblk,outlen,cellrefp)

Description

codeblk = lteBCH(enb,trblk) returns a vector of BCH transport channel coded bits. The encoding process includes CRC calculation and attachment, convolutional encoding, and rate matching as defined in TS 36.212 [1], Section 5.3.1.

The rate matching internal to the coding results in many repetitions of the coded block. This repetition is deliberate so that part of a received block can be successfully decoded in isolation. Typically, the receiver can recover the BCH bits from the reception of just one frame (¼ of the transmitted block), rather than waiting 40 ms (four frames) for the full block to be received.

codeblk = lteBCH(trblk,outlen,cellrefp) returns the vector rate-matched to the output length outlen. The argument cellrefp controls the CRC port mask.

Examples

Encode BCH Information Bits

Generate the BCH coded vector of length 1920, corresponding to normal cyclic prefix.

enb = struct('CellRefP',1,'CyclicPrefix','Normal');
bchCoded = lteBCH(enb,ones(24,1));
bchCodedSize = size(bchCoded)

bchCodedSize = 1×2

        1920           1

Input Arguments

enb — eNodeB cell-wide settings

scalar structure

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

Parameter Field	Required or Optional	Values	Description
CellRefP	Required	1, 2, 4	Number of cell-specific reference signal (CRS) antenna ports
CyclicPrefix	Optional	'Normal' (default), 'Extended'	Cyclic prefix length

trblk — Transport block

numeric vector

Transport block, specified as a numeric vector of length 24 bits. This argument represents the transport block delivered to the BCH every 40 ms.

outlen — Output length

numeric scalar

Output length, specified as a numeric scalar.

Data Types: double

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

0 | 1 | 2 | 4

Number of cell-specific reference signal (CRS) antenna ports, specified as 0, 1, 2, or 4. To turn the CRC port mask off, set cellrefp to 0.

Output Arguments

codeblk — BCH transport channel coded bits

numeric column vector

BCH transport channel coded bits, returned as an integer column vector with 1920 bits for normal cyclic prefix or 1728 bits for extended cyclic prefix.

Data Types: int8

References

[1] 3GPP TS 36.212. “Evolved Universal Terrestrial Radio Access (E-UTRA); Multiplexing and channel coding.” 3rd Generation Partnership Project; Technical Specification Group Radio Access Network. URL: http://www.3gpp.org.

Version History

Introduced in R2014a