Physical Broadcast Channel (PBCH)

This module implements the physical broadcast channel. The implementation of these modules is based on [3GPPTS38211pbch].

PBCH Transmitter

class toolkit5G.PhysicalChannels.PBCH(carrierFreq, choiceBit, subCarrierSpacingCommon, DMRSTypeAPosition, controlResourceSet0, searchSpace0, cellBarred, intraFrequencyReselection, systemFrameNumber, ssbSubCarrierOffset, hrfBit, ssbIndex, cellID, nssbCandidatesInHrf)

Generates the QPSK symbols processed by PBCH chain as per Section 7.3.2.5 of [3GPPTS38211pbch]. The PBCH symbols generated by the chain can be directly inserted into SSB Grid.

Parameters:

• carrierFreq (number) – Defines the carrier frequency considered for simulation \(\in [0.5, 52.6]\) GHz.

• choiceBit (number) – Defines the choice bit from MIB information \(\in \{0, 1\}\).

• subCarrierSpacingCommon (number) – Defines subCarrierSpacingCommon information for SSB which \(\in \{15000, 30000\}\) for frequency range-1 (carrierFreq < 6 GHz) and \(\in \{120000, 240000\}\) for frequency range-1 (6 GHz <carrierFreq < 52.6 GHz). Indicates the Subcarrier spacing for SIB1, Msg.2/4 for initial access and SI-messages.

• DMRSTypeAPosition (str) – Defines dmrs-TypeA-Position information in MIB. It is used to indicate position of (first) DL DM-RS. \(\in \{\text{"pos2", "pos3"}\}\)

• controlResourceSet0 ((N,), int) – Defines common ControlResourceSet (CORESET). It is one of the most crucial information for UE to decode the SIB1.

• searchSpace0 ((N,), int) – Defines searchSpace0 in MIB. It is one of the most crucial information for UE to decode the SIB1.

• cellBarred (int) – Defines cellBarred in MIB \(\in \{0, 1\}\). This field indicates whether or not UEs in the cell are allowed to access the cell; ‘barred’ indicates, the UEs are not allowed to access the cell.

• intraFrequencyReselection (int) – Defines intraFrequencyReselection in MIB \(\in \{0, 1\}\). This field controls cell selection/reselection to intra-frequency cells when the highest ranked cell is barred (as indicated by cellBarred) or treated as barred by the UE.

• systemFrameNumber (int) – Defines system frame number \(\in \{0, 1, \dots, 1023\}\) requires 10 bits for representation. The 6 MSB bits of the 10-bit SFN are carried by MIB-IE from higher layers and the 4 LSB bits of the SFN are conveyed in the PBCH transport block as part of channel coding (i.e. outside the MIB encoding).

• ssbSubCarrierOffset ((N,), int) – Defines \(\text{k}_{SSB}\) indicates the frequency domain offset between SSB and the overall resource block grid in number of subcarriers. For FR1, it takes 24 values \(\in \{0, 1, \dots, 23\}\) and for FR2 it takes 12 values \(\in \{0, 1, \dots, 11\}\). This field may indicate that this cell does not provide SIB1 and that there is hence no common CORESET. In this case, the field pdcch-ConfigSIB1 may indicate the frequency positions where the UE may (not) find a SS/PBCH with a control resource set and search space for SIB1

• hrfBit (int) – Defines the half frame bit \(\in \{0, 1\}\). This bit is cleared (set to 0) if SSB is broadcasted in the first half-frame or set to 1 otherwise. This information is combined with SSB index for frame synchronization.

• ssbIndex ((N,), int) – Defines the index of the SSB within SSB burst set \(\in \{0, 1, \dots, \text{L}_\text{max}-1\}\).

• cellID (int) – Defines the cell-ID \(\in \{0, 1, \dots, 1007\}\).

• nssbCandidatesInHrf (int) – Defines the maximum number of candidate SSBs (\(\text{L}_\text{max}\)) within an SS burst set. The values of this parameter depends upon the carrier frequency.

Important

The size of controlResourceSet0, searchSpace0, ssbIndex and ssbSubCarrierOffset must be consistent.

Input:

No input required.

Output:

[N, 432], np.complex64 where N denotes the number of MIBs. Its value depends on size of controlResourceSet0, searchSpace0, ssbSubCarrierOffset , and ssbIndex.

Attributes:

• mib (Object of Class MIBGeneration)

• pbchIL (Object of Class PBCHInterleaver)

• pbchScr (Object of Class Scrambler)

• crcEncoder (Object of Class CRCEncoder)

• pbch_IiL (Object of Class InputBitInterleaver)

• encoder (Object of Class PolarEncoder5G)

• sbBIL (Object of Class Subblock_Interleaver)

• rateMatch (Object of Class BitSelection)

• scr2 (Object of Class Scrambler)

• payloadMIB ((…, 32), np.integer) – Defines MIB Payload.

• mibSequence ((…, 32), np.integer) – Defines the Requenced MIB Payload as per section of 3GPP TS 38.211.

• ilBits ((…, 32), np.integer) – Defines the PBCH interleaved Payload as per section of 3GPP TS 38.211.

• scrBits ((…, 32), np.integer) – Defines the PBCH-1 scrambled Payload as per section of 3GPP TS 38.211.

• payloadCRC ((…, 56), np.integer) – Defines the CRC encoded Payload as per section of 3GPP TS 38.211.

• iILBits ((…, 56), np.integer) – Defines the input bit interleaved Payload as per section of 3GPP TS 38.211.

• encBits ((…, 512), np.integer) – Defines the polar encoded Payload as per section of 3GPP TS 38.211.

• sBIL_bits ((…, 512), np.integer) – Defines the sub-block interleaved Payload as per section of 3GPP TS 38.211.

• rmBits ((…, 864), np.integer) – Defines the rate-matched Payload as per section of 3GPP TS 38.211.

• scr2bits ((…, 864), np.integer) – Defines the PBCH-2 scrambled Payload as per section of 3GPP TS 38.211.

property chIL_bits

Defines the output of Channel Interleaver. This is passed as input to PBCH Scrambler.

property encBits

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

property iILBits

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

property ilBits

Defines the output of PBCH Interleaver. This is passed as input to PBCH Scrambler-1.

property mib

Defines the object of MIB Generation!

property payloadCRC

Defines the output of Cyclic Redundancy Check. This is passed as input to Input Block Interleaver.

property payloadMIB

Defines the output of MIB Generator. This is passed as input to PBCH Interleaver.

property rmBits

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

property sBIL_bits

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

property scr2bits

Defines the output of PBCH Scrambler-2. This is passed as input to QPSK Symbol Mapper.

property scrBits

Defines the output of PBCH Scrambler-1. This is passed as input to Cyclic Redundancy Check.

PBCH Receiver

class toolkit5G.PhysicalChannels.PBCHDecoder(carrierFreq, cellID, nssbCandidatesInHrf, ssbIndex, polarDecType, symbolDemapperType)

Generates the QPSK symbols processed by PBCH chain as per Section 7.3.2.5 of [3GPPTS38211pbch]. The PBCH symbols generated by the chain can be directly inserted into SSB Grid.

Parameters:

• carrierFreq (number) – Defines the carrier frequency considered for simulation \(\in [0.5, 52.6]\) GHz.

• cellID (int) – Defines the cell-ID \(\in \{0, 1, \dots, 1007\}\).

• nssbCandidatesInHrf (int) – Defines the maximum number of candidate SSBs (\(\text{L}_\text{max}\)) within an SS burst set. The values of this parameter depends upon the carrier frequency.

• ssbIndex ((N,), int) – Defines the index of the SSB within SSB burst set \(\in \{0, 1, \dots, \text{L}_\text{max}-1\}\).

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

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

Input:

• [N, 432], np.complex64 where N denotes the number of MIBs to be recovered.

• SNR (np.number) – Signal to noise ratio in linear scale

• mibFlag (bool) – Flag to decode MIB information from PBCH payload bits

Output:

(MIBExtraction, crcCheck) where –

• MIBExtraction is None if mibFlag is False and object of MIBExtraction class otherwise.

• crcCheck is (N, 1) boolean array where N is number of PBCH payloads.

Attributes:

• mib (Object of Class MIBGeneration)

• pbchIL (Object of Class PBCHInterleaver)

• pbchScr (Object of Class Scrambler)

• crcEncoder (Object of Class CRCEncoder)

• pbch_IiL (Object of Class InputBitInterleaver)

• encoder (Object of Class PolarEncoder5G)

• sbBIL (Object of Class Subblock_Interleaver)

• rateMatch (Object of Class BitSelection)

• scr2 (Object of Class Scrambler)

• payloadMIB ((…, 32), np.integer) – Defines MIB Payload.

• mibSequence ((…, 32), np.integer) – Defines the Requenced MIB Payload as per section of 3GPP TS 38.211.

• ilBits ((…, 32), np.integer) – Defines the PBCH interleaved Payload as per section of 3GPP TS 38.211.

• scrBits ((…, 32), np.integer) – Defines the PBCH-1 scrambled Payload as per section of 3GPP TS 38.211.

• payloadCRC ((…, 56), np.integer) – Defines the CRC encoded Payload as per section of 3GPP TS 38.211.

• iILBits ((…, 56), np.integer) – Defines the input bit interleaved Payload as per section of 3GPP TS 38.211.

• encBits ((…, 512), np.integer) – Defines the polar encoded Payload as per section of 3GPP TS 38.211.

• sBIL_bits ((…, 512), np.integer) – Defines the sub-block interleaved Payload as per section of 3GPP TS 38.211.

• rmBits ((…, 864), np.integer) – Defines the rate-matched Payload as per section of 3GPP TS 38.211.

• scr2bits ((…, 864), np.integer) – Defines the PBCH-2 scrambled Payload as per section of 3GPP TS 38.211.

Note

These Attributes are Accessible only when mibFlag is set to True

Raises:

• ValueError – [PBCHDecoder-Error]: ‘pbchE’ must be a numPy array of size (…, 432)!

• ValueError – [PBCHDecoder-Error]: ‘snr’ must be a np.number!

• ValueError – [PBCHDecoder-Error]: ‘mibFlag’ must be a bool!

property channelDeInterleaverBits

Defines the output of Channel DeInterleaver. This is passed as input to Bit De-Selection.

property crcCheck

Defines the output of CRC Decoder and indicates whether PBCH Payload bits are erroneous or not!

property deCRCBits

Defines the output of CRC Decoder. It is passed as input to PBCH De-Interleaver.

property deScrambledBits

Defines the output of De-Scrambler-1. This is passed as input to Cyclic Redundancy Check Decoder.

property descrambled2LLRs

Defines the output of Descrambler-2. This is passed as input to Channel DeInterleaver.

property inputDeinteleavedBits

Defines the output of Input Bit De-Interleaver. This is passed as input to De-Scrambler-1.

property llr

Defines the Log Likelihood Ratio (LLR) (output of Demapper). This is passed as input to Descrambler-2.

property mibRx

Defines the object of MIB Extraction!

property pbchDeInterleavedBits

Defines the output of PBCH De-Interleaver. It is passed as input to MIB Extraction.

property polarDecodedBits

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

property rateDematedBits

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

property subBlockDeinterleavedBits

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

PBCH 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:

[3GPPTS38211pbch] (1,2,3)

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