Code Block Concatenation

Code Block Concatenation: Transmitter

Each codeblock is individually channel coded and broken further into 1 or 2 codeblock segments. All these codeblock segments are concatenated by the last module of the upper physical layer chain. The implementation is compliant with section 5.5 of [3GPPTS38212]. An example to demonstrate the implementation is shown below:

Example:

numBatches = 5    # Number of user equipments
numCBs     = 2    # Number of code blocks
#bit generation
bits = np.random.randint(2, size = (numBatches, numCBs, 200))

numTargetBits  = 4224  # Number of target bits

cbConcatenated = CodeBlockConcatenation(numTargetBits)(bits) # Returns the concatenated code blocks

The details of the API of codeblock concatenation is detailed below.

class toolkit5G.ChannelCoder.PolarCoder.CodeBlockConcatenation(numTargetBits)[source]

This modules implements the codeblock concatenation for Polar codes as described in section of []_

Code Block Segregation: Receiver

The block performs the opposite of code-block concatenation. It breaks the received codeword into multiple codeblock-segments for rate matching.

Example:

numInfoBits   = 1555  # Payload size (Number of Information bits)
numOfSegments = 2     # Number of codeblocks
E             = 2112  # Rate matching output sequence length

#bit generation
bits = np.random.randint(2, size = (numBatches, 4224))


codewordSegregation = CodeBlockSegregation(numInfoBits)(bits, E, numOfSegments) # Returns the code blocks

The details of the input output interface of codeblock segregation is shown below:

class toolkit5G.ChannelCoder.PolarCoder.CodeBlockSegregation[source]
Parameters:

None

Input:

inputBits ([\(\dots, \text{N}_\text{cb}, \text{K}\)], np.float32) – code-blocks, where \(\text{N}_\text{cb}\) defines the number of code blocks and \(\text{K}\) defines the length of LDPC encoded code-block.

Output:

[ \(\dots, \text{N}_\text{cb} \times \text{K'}\)] – returns the transport block having a size \(\text{N}_\text{cb} \times \text{K'}\) where \(\text{K'}\): includes code block CRC and few 0s. The detailed relation between \(\text{K'}\) and \(\text{K}\) is defined in section 5.2.2 of [3GPPTS38212_LDPC].

Raises:

  • ValueError – “[Error-CodeBlockAggregation]: ‘inputBits’ must be an Numpy array of numbers!”

  • ValueError – “[Error-CodeBlockSegmentation]: ‘codeRate’ should either be an float!”

  • ValueError – “[Error-CodeBlockSegmentation]: ‘codeRate’ should be in (0,1]!”

  • ValueError – “[Error-CodeBlockAggregation]: ‘tbSize’ should either be an int!”

  • ValueError – “[Error-CodeBlockAggregation]: ‘tbSize’ should be non-zero +ve number!”