Broadcast channel


  • codeblk = lteBCH(enb,trblk)



codeblk = lteBCH(enb,trblk) returns a vector of BCH transport channel coded bits.

The input argument, trblk, is a vector of 24 bits. It represents the information bits delivered to the broadcast channel (BCH) every 40 ms. The coded output vector, codeblk, contains 1920 bits for normal cyclic prefix or 1728 bits for extended cyclic prefix.

Given the small input size, which is 24, compared with the large output size, which is 1920 or 1728, the rate matching internal to the coding results in a large number of repetitions of the coded block. This repetition is deliberate so that part of a received block can be successfully decoded in isolation. For example, the receiver can recover the BCH bits from the reception of just one frame, ¼ of the transmitted block, rather than waiting 40 ms, or 4 frames, for the full block to be received.


collapse all

Encode BCH Information Bits

Generate a BCH-coded block of length 1920.

enb = struct('CellRefP',1,'CyclicPrefix','Normal');
bchCoded = lteBCH(enb,ones(24,1));
        1920           1

Input Arguments

collapse all

enb — eNodeB cell-wide settingsscalar structure

eNodeB cell-wide settings structure that can contain these parameter fields.

Parameter FieldRequired or OptionalValuesDescription

1, 2, 4

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


'Normal' (default), 'Extended'

Cyclic prefix length

trblk — Transport blocknumeric 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.

Output Arguments

collapse all

codeblk — BCH transport channel coded bitsnumeric column vector

BCH transport channel coded bits, returned as an integer column vector.

Data Types: int8

Introduced in R2014a

Was this topic helpful?