Layer Mapper

The layer mapper divides the symbols across

Layer Mapper: Transmitter

Example

coderate = 0.650390625 #Code Rate
#crcTBlock ---> Transport Block with CRC bits attached

cbSegment   = CodeBlockSegmentation(coderate) # Object for processing the code blocks
codeblocks  = cbSegment(crcTBlock) # Attach the segment the TB and attach the CRC to TB based on 38.212

class toolkit5G.PhysicalChannels.PDSCH.LayerMapper(numCodewords, numLayers)

Defines the layer mapper for physical downlink shared channel and physical uplink shared channel. The implementation details are provided in section 7.3.1.3 of [3GPPTS38211pdsch].

Parameters:

• numCodewords (int) – Number of codewords to be layer mapped $\in \{1,2\}$

• numLayers (int) – Number of layer to which these codewords will be mapped $\in \{1,2,3,4,5,6,7,8\}$

Important

The numLayers should be less $\le 4$ if numCodewords is 1 otherwise it should be $4\le$ numLayers $\le 8$.

Tip

For numCodewords $=2$, the distribution of layers across the codewords is shown in table-1 demonstrated above.

Input:

• codeword1 ([…, ${\text{E}}_1$], np.complex64) – Codeword-1 to be mapped to the layers.

• codeword2 ([…, ${\text{E}}_2$], np.complex64 or None) – Codeword-2 to be mapped to the layers. It should be passed only when the numCodewords is 2. Default value is None.

Note

For numCodewords $=1$, ${\text{E}}_1$ should be multiple of numLayers. For numCodewords $=2$, ${\text{E}}_1$ and ${\text{E}}_2$ should be multiple of ${\text{N}}_{\text{L}}^1$ and ${\text{N}}_{\text{L}}^2$ repectively where ${\text{N}}_{\text{L}}^1+{\text{N}}_{\text{L}}^2=$ numLayers.

Output:

[…, numLayers, $\text{E}$], np.complex64 – Layer mapped symbols.

Note

For numCodewords $=1$, $\text{E}=\frac{{\text{E}}_1}{{\text{N}}_{\text{L}}}$ where ${\text{N}}_{\text{L}}$ is numLayers. For numCodewords $=2$, $\text{E}=\frac{{\text{E}}_2}{{\text{N}}_{\text{L}}^2}=\frac{{\text{E}}_1}{{\text{N}}_{\text{L}}^1}$ where ${\text{N}}_{\text{L}}^1+{\text{N}}_{\text{L}}^2=$ numLayers.

Raises:

• ValueError – [Error-LayerMapper]: numSymbols in ‘codeword1’ is not matching (numSymbolPerLayer x numLayers)!

• ValueError – [Error-LayerMapper]: numSymbols in ‘codeword1’ is not matching (numSymbolPerLayer x numLayers)!

• ValueError – [Error-LayerMapper]: ‘codeword1’ should be 2-dimension array (numBatch x numSymbols)!

• ValueError – [Error-LayerMapper]: ‘codeword2’ should be passed for 2 codewords!

• ValueError – [Error-LayerMapper]: numSymbols in ‘codeword2’ is not matching (numSymbolPerLayer x numLayers)!

• ValueError – [Error-LayerMapper]: numSymbols in ‘codeword2’ is not matching (numSymbolPerLayer x numLayers)!

• ValueError – [Error-LayerMapper]: ‘codeword2’ should be 2-dimension array (numBatch x numSymbols)!

• ValueError – [Error-LayerMapper]: Inconsistent dimensions and size for both two codewords!

• ValueError – [Error-LayerMapper]: number of symbols per layer must be same for both the codewords!

• ValueError – [Error-LayerMapper]: ‘numCodewords’ should either be an integer!

• ValueError – [Error-LayerMapper]: ‘numCodewords’ should be either 1 or 2!

• ValueError – [Error-LayerMapper]: ‘numLayers’ should either be an integer!

• ValueError – [Error-LayerMapper]: For “+str(self.__numCodewords)+” ‘Codewords’, ‘numLayers’ should either be from interval [1, “+str(numLayerperCW[self.__numCodewords])+”]!

Layer Demapper: Receiver

Example

# rmBits ---> Rate Matched Output Block after Interleaving

codeword   = CodeBlockConcatenation()(rmBits) #Performs Code Block Concatenation

class toolkit5G.PhysicalChannels.PDSCH.LayerDemapper(numCodewords, numLayers)

Defines the layer demapper for physical downlink shared channel and physical uplink shared channel. It performs opposite operation to layer mapping. The implementation details are provided in section 7.3.1.3 of [3GPPTS38211pdsch].

Parameters:

• numCodewords (int) – Number of codewords to be layer mapped $\in \{1,2\}$

• numLayers (int) – Number of layer to which these codewords will be mapped $\in \{1,2,3,4,5,6,7,8\}$

Important

The numLayers should be less $\le 4$ if numCodewords is 1 otherwise it should be $4\le$ numLayers $\le 8$.

Tip

For numCodewords $=2$, the distribution of layers across the codewords is shown in table-1 demonstrated above.

Input:

payload ([…, numLayers, $\text{E}$], np.complex64) – Layer mapped symbo

Output:

• […, ${\text{E}}_1$], np.complex64 – Layer demapped symbol Codeword-1.

• […, ${\text{E}}_2$], np.complex64 or None – Layer demapped symbol Codeword-2. It should be passed only when the numCodewords is 2. Default value is None.

Note

For numCodewords $=1$, ${\text{E}}_1={\text{N}}_{\text{L}}\times \text{E}$ where ${\text{N}}_{\text{L}}=$ numLayers. For numCodewords $=2$, ${\text{E}}_1={\text{N}}_{\text{L}}^1\times \text{E}$ and ${\text{E}}_2={\text{N}}_{\text{L}}^2\times \text{E}$ where ${\text{N}}_{\text{L}}^1+{\text{N}}_{\text{L}}^2=$ numLayers.

Raises:

• ValueError – [Error-LayerDemapper]: payload has “+str(numLayers)+” layers, codeword-1 and codeword-2 are expected to consists of “+str(self.__numLayers1)+” and “+str(self.__numLayers2)+” respectively

• ValueError – [Error-LayerDemapper]: ‘Input Array’ should be a 3 dimension array (numBatches x numLayers x numSymbolsPerLayers)!

• ValueError – [Error-LayerDemapper]: ‘numCodewords’ should either be an integer!

• ValueError – [Error-LayerDemapper]: ‘numCodewords’ should be either 1 or 2!

• ValueError – [Error-LayerDemapper]: ‘numLayers’ should either be an integer!

• ValueError – [Error-LayerDemapper]: For “+str(self.__numCodewords)+” ‘Codewords’, ‘numLayers’ should either be from interval [1, “+str(numLayerperCW[self.__numCodewords])+”]!