5G/NR - PDSCH/PUSCH Mapping Type                              Home : www.sharetechnote.com

 

 

 

 

 

PDSCH/PUSCH Mapping Type

 

Both PDSCH and PUSCH has two different types of mapping called Type A and Type B. These types are characterized by DMRS type (PDSCH DMRS type and PUSCH DMRS type) and SLIV table as shown below.

 

< 38.214-Table 5.1.2.1-1: Valid S and L combinations >

 

< 38.214-Table 6.1.2.1-1: Valid S and L combinations >

 

 

 

< PDSCH Mapping Type >

 

Type A :

  • PDSCH DMRS is Type A
    • The DMRS location is fixed to 3rd (pos2) or 4th(pos3)
  • PDSCH Starting Symbol can be 0~3
  • PDSCH Length can be 3~14 in case of normal CP and 3~12 in case of extended CP
  • the DMRS symbol can start only at symbol 2 or 3 regardless of PDSCH start and length. It implies this cannot be used when PDSCH start symbol is greater than 3. This is related to the row 'Type A' in PDSCH SLIV table. This type is used for slot based scheduling.

 

Type B :

  • PDSCH DMRS is Type B
    • The DMRS location is fixed to the first symbol of the allocated PDSCH
  • PDSCH Starting Symbol can be 0~12 in case of Normal CP and 0~10 in case of extended CP
  • PDSCH Length can only be 2 or 4 or 7 in case of Normal CP and 2 or 4 or 6 in case of extended CP
  • the DMRS symbol can start at the first PDSCH symbol regardless of PDSCH start. This is related to the row 'Type B'  in PDSCH SLIV table. This type is used for mini-slot based scheduling

 

 

 

< PUSCH Mapping Type >

 

Type A :

  • PUSCH DMRS is Type A
    • The DMRS location is fixed to 3rd (pos2) or 4th(pos3)
  • PUSCH Starting Symbol is always 0
  • PDSCH Length can be 4~14 in case of normal CP and 4~12 in case of extended CP

 

Type B :

  • PUSCH DMRS is Type B
    • The DMRS location is fixed to the first symbol of the allocated PUSCH
  • PUSCH Starting Symbol can be 0~13 in case of Normal CP and 0~12 in case of extended CP
  • PUSCH Length can only be 1~14 in case of Normal CP and 1~12 in case of extended CP

 

 

 

UE Capability

 

UE would inform NW of it's supportability about PDSCH Mapping Type via UE Capability Information message.

 

Phy-ParametersCommon ::=    SEQUENCE {

    ...

    pdsch-MappingTypeA                  ENUMERATED {supported}          OPTIONAL,

    pdsch-MappingTypeB                  ENUMERATED {supported}          OPTIONAL,

    ...

    ...

}

 

 

 

 

Reference

 

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