Content for TS 38.323 Word version: 18.3.0
6 Protocol data units, formats, and parameters
6.1 Protocol data units
6.1.1 Data PDU
6.1.2 Control PDU
6.2 Formats
6.2.1 General
6.2.2 Data PDU
6.2.2.1 Data PDU for SRBs
6.2.2.2 Data PDU for DRBs and MRBs with 12 bits PDCP SN
6.2.2.3 Data PDU for DRBs and MRBs with 18 bits PDCP SN
6.2.2.4 Data PDU for sidelink DRBs for groupcast and broadcast, for the sidelink SRB0 and for the sidelink SRB4
6.2.2.5 Data PDU for sidelink SRBs for unicast
6.2.2.6 Data PDU for sidelink DRBs for unicast with 12 bits PDCP SN
6.2.2.7 Data PDU for sidelink DRBs for unicast with 18 bits PDCP SN
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6 Protocol data units, formats, and parameters p. 36
6.1 Protocol data units p. 36
6.1.1 Data PDU p. 36
The PDCP Data PDU is used to convey one or more of followings in addition to the PDU header:
- user plane data;
- control plane data;
- a MAC-I.
6.1.2 Control PDU p. 36
The PDCP Control PDU is used to convey one of followings in addition to the PDU header:
- a PDCP status report;
- an interspersed ROHC feedback;
- an EHC feedback;
- a UDC feedback;
- a PDCP SN gap report.
6.2 Formats p. 36
6.2.1 General p. 36
A PDCP PDU is a bit string that is byte aligned (i.e. multiple of 8 bits) in length. In the figures in clause 6.2, bit strings are represented by tables in which the most significant bit is the leftmost bit of the first line of the table, the least significant bit is the rightmost bit on the last line of the table, and more generally the bit string is to be read from left to right and then in the reading order of the lines. The bit order of each parameter field within a PDCP PDU is represented with the first and most significant bit in the leftmost bit and the last and least significant bit in the rightmost bit.
PDCP SDUs are bit strings that are byte aligned (i.e. multiple of 8 bits) in length. A compressed or uncompressed SDU is included into a PDCP Data PDU from the first bit onward.
6.2.2 Data PDU p. 37
6.2.2.1 Data PDU for SRBs p. 37
Figure 6.2.2.1-1 shows the format of the PDCP Data PDU with 12 bits PDCP SN. This format is applicable for SRBs.
6.2.2.2 Data PDU for DRBs and MRBs with 12 bits PDCP SN p. 37
Figure 6.2.2.2-1 shows the format of the PDCP Data PDU with 12 bits PDCP SN. This format is applicable for UM DRBs, AM DRBs, UM MRBs and AM MRBs.
6.2.2.3 Data PDU for DRBs and MRBs with 18 bits PDCP SN p. 38
Figure 6.2.2.3-1 shows the format of the PDCP Data PDU with 18 bits PDCP SN. This format is applicable for UM DRBs, AM DRBs, UM MRBs and AM MRBs.
6.2.2.4 Data PDU for sidelink DRBs for groupcast and broadcast, for the sidelink SRB0 and for the sidelink SRB4 |R16| p. 38
Figure 6.2.2.4-1 shows the format of the PDCP Data PDU with 12 bits PDCP SN. This format is applicable for sidelink DRBs for groupcast and broadcast, for the sidelink SRB0 and for the sidelink SRB4.
6.2.2.5 Data PDU for sidelink SRBs for unicast |R16| p. 39
Figure 6.2.2.5-1 shows the format of the PDCP Data PDU with 12 bits PDCP SN. This format is applicable for sidelink SRB1, SRB2 and SRB3 for unicast.
6.2.2.6 Data PDU for sidelink DRBs for unicast with 12 bits PDCP SN |R16| p. 39
Figure 6.2.2.6-1 shows the format of the PDCP Data PDU with 12 bits PDCP SN. This format is applicable for sidelink DRBs for unicast.
6.2.2.7 Data PDU for sidelink DRBs for unicast with 18 bits PDCP SN |R16| p. 40
Figure 6.2.2.7-1 shows the format of the PDCP Data PDU with 18 bits PDCP SN. This format is applicable for sidelink DRBs for unicast.
