Physical Downlink Control Channel (PDCCH)

This module implements the physical downlink control channel. The implementation of these modules is based on [3GPPTS38211pdcch].

PDCCH Transmitter

class toolkit5G.PhysicalChannels.PDCCH(K, E, rnti, nID)

Generates the QPSK symbols processed by PBCH chain as per Section 7.3.2.5 of [3GPPTS38211pdcch]. The PBCH symbols generated by the chain can be directly inserted into SSB Grid.

Parameters:

• K (int) – Size of payload input to the PDCCH chain.

• E (int) – Number of target bits for PDCCH chain (output of the Polar rate matcher).

• rnti (int) – It defines the radio network temporary identifier (RNTI) \(\in \{1,2,..,65519\}\).

• nID (int) – It is defined by pdcch-DMRS-ScramblingID \(\in \{0,1,2,..,65535\}\).

Important

All the parameters (K, E, rnti and nID) are same for all the N payload vectors.

Input:

dciPayload ([N, K], np.int - denoting N PDCCH payload vectors each of size K.)

Output:

[N, E/2], np.complex64 - denoting N PDCCH coded vectors of \(\frac{\text{E}}{2}\) QPSK symbols each.

property dciBIL

Defines the output of Sub Block Interleaver. This is passed as input to Bit Selection.

property dciCRC

Defines the output of Cyclic Redundancy Check. This is passed as input to RNTI Masking.

property dciIBI

Defines the output of Input Block Interleaver. This is passed as input to Polar Encoder.

property dciRM

Defines the output of Bit Selection. This is passed as input to PDCCH Scrambler.

property dciRNTI

Defines the output of RNTI Masking. This is passed as input to Input Block Interleaver.

property dciSCR

Defines the output of PDCCH Scrambler. This is passed as input to QPSK Symbol Mapper.

property encBits

Defines the output of Polar Encoder. This is passed as input to Sub Block Interleaver.

PDCCH Receiver

class toolkit5G.PhysicalChannels.PDCCHDecoder(K, E, rnti, nID, decoderType='SC', demappingMethod='maxlog')

Generates the QPSK symbols processed by PBCH chain as per Section 7.3.2.5 of [3GPPTS38211pdcch]. The PBCH symbols generated by the chain can be directly inserted into SSB Grid.

Parameters:

• K (int) – Size of payload input to the PDCCH chain.

• E (int) – Number of target bits for PDCCH chain (output of the Polar rate matcher).

• rnti (int) – It defines the radio network temporary identifier (RNTI) \(\in \{1,2,..,65519\}\).

• nID (int) – It is defined by pdcch-DMRS-ScramblingID \(\in \{0,1,2,..,65535\}\).

• polarDecType (str) – Defines the Polar Decoder Type used in PBCH receiver chain.

• symbolDemapperType (str) – Defines the Symbol Demapper Type used for demapping QPSK symbols.

Important

All the parameters (K, E, rnti and nID) are same for all the N payload vectors.

Input:

• equalizedSymbols ([N, E/2], np.int - denoting N PDCCH vectors each having \(\frac{\text{E}}{2}\) equalized QPSK symbols.)

• snr (float - Signal to noise ratio (SNR).)

Output:

[N, K], np.complex64 - denoting N PDCCH decoded payload vectors of K bits each.

property check

Defines the output of CRC Decoder and indicates whether DCI information is erroneous or not!

property dciBits

Defines the output of CRC Decoder and PDCCH Decoder.

property decodedBits

Defines the output of Polar Decoder. This is passed as input to Input Bit De-Interleaver.

property dematchedBits

Defines the output of Bit De-Selection. This is passed as input to Input Bit De-Interleaver.

property descrambledLLRs

Defines the output of Descrambler. This is passed as input to Input Block Interleaver.

property ibDILBits

Defines the output of Input Bit De-Interleaver. This is passed as input to RNTI De-Masking.

property llr

Defines the output of Log Likelihood Ratio (LLR). This is passed as input to Descrambler.

property sbdBits

Defines the output of Sub Block De-Interleaver. This is passed as input to Polar Decoder.

property unmaskedBits

Defines the output of RNTI De-Masking. This is passed as input to Cyclic Redundancy Check Decoder.

PDCCH Components

• Cyclic Redundency Check
  • Cyclic Redundancy Check
• RNTI Masking
  • RNTI Masking
    • RNTImasking
      • RNTImasking.rnti
• Input Bit Interleaver
  • Code-block Processing: Transmitter
    • Code-block Segmentation
      • CodeBlockSegmentation
    • Code-block Concatenation
      • CodeBlockConcatenation
  • Code-block Processing: Receiver
    • Code-block Segregation
      • CodeBlockSegregation
    • Code-block Aggregation
      • CodeBlockAggregation
  • Input Bit Interleavers
    • Input Bit Interleaver
      • InputBitInterleaver
    • Input Bit Deinterleaver
      • InputBitDeInterleaver
• Polar Coder
  • Polar Codes
    • Polar Encoder
      • PolarEncoder5G
        • PolarEncoder5G.N
    • Polar Decoder
      • PolarDecoder5G
        • PolarDecoder5G.E
        • PolarDecoder5G.K
        • PolarDecoder5G.N
        • PolarDecoder5G.dec_type
        • PolarDecoder5G.llr_max
        • PolarDecoder5G.output_dtype
    • Polar Codec Components
• Rate Matching
  • Sub Block Interleaver
    • Sub Block Interleaver for Polar Coder
      • Sub-block Interleaver
        • Subblock_Interleaver
      • Sub-block De-interleaver
        • Subblock_DeInterleaver
  • Bit Selection
    • Bit Selection for Polar Coder
      • Bit Selection
        • BitSelection
      • Bit De-selection
        • BitDeSelection
  • Channel Interleaver
    • Channel Interleaver for Polar Coder
      • Channel Interleaver
        • ChannelInterleaver
      • Channel De-interleaver
        • ChannelDeInterleaver
• Scrambling: PDCCH
  • Scrambling
  • Scrambler
    • Scrambler
      • Scrambler.Lmax
      • Scrambler.c_init
      • Scrambler.id
      • Scrambler.mu
      • Scrambler.nID
      • Scrambler.purpose
      • Scrambler.q
      • Scrambler.rnti
      • Scrambler.ssbIndex
  • Descrambler
    • DeScrambler
      • DeScrambler.Lmax
      • DeScrambler.c_init
      • DeScrambler.id
      • DeScrambler.mu
      • DeScrambler.nID
      • DeScrambler.purpose
      • DeScrambler.q
      • DeScrambler.rnti
      • DeScrambler.ssbIndex
• Modulation
  • Symbol Mapping
  • Mapper
    • Mapper
  • Demapper
    • Demapper

References:

[3GPPTS38211pdcch] (1,2,3)

(3GPP TS 38.211 version 17.1.0 Release 17) 5G;NR;Physical channels and modulation.