6 Protocol data units, formats, and parameters
37.3243GPPEvolved Universal Terrestrial Radio Access (E-UTRA) and NRRelease 17Service Data Adaptation Protocol (SDAP) specificationTS
6.1 Protocol data units
6.1.1 Data PDU
The SDAP Data PDU is used to convey one or more of followings:
– SDAP header;
– user plane data.
6.1.2 Control PDU
a) End-Marker Control PDU
End-Marker control PDU is used by the SDAP entity at UE to indicate that it stops the mapping of the SDAP SDU of the QoS flow indicated by the QFI/PQFI to the DRB/SL-DRB on which the End-Marker control PDU is transmitted.
6.2 Formats
6.2.1 General
A SDAP 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 first and most significant bit is the left most bit of the first line of the table, the last and least significant bit is the rightmost bit of 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.
SDAP SDUs are bit strings that are byte aligned (i.e. multiple of 8 bits) in length. An SDAP SDU is included into a SDAP PDU from the first bit onward.
For groupcast and broadcast of NR sidelink communication, only SDAP data PDU without SDAP header is supported.
6.2.2 Data PDU
6.2.2.1 Data PDU without SDAP header
An SDAP PDU consists only of a data field and does not consist of any SDAP header, as described in Figure 6.2.2.1-1.
Figure 6.2.2.1-1: SDAP Data PDU format without SDAP header
6.2.2.2 DL Data PDU with SDAP header
Figure 6.2.2.2 – 1 shows the format of SDAP Data PDU of DL with SDAP header being configured.
Figure 6.2.2.2-1: DL SDAP Data PDU format with SDAP header
6.2.2.3 UL Data PDU with SDAP header
Figure 6.2.2.3 – 1 shows the format of SDAP Data PDU of UL with SDAP header being configured.
Figure 6.2.2.3-1: UL SDAP Data PDU format with SDAP header
6.2.2.4 SL Data PDU with SDAP header for unicast of NR sidelink communication
Figure 6.2.2.4–1 shows the format of SDAP Data PDU for unicast of NR sidelink communication with SDAP header being configured.
Figure 6.2.2.4-1: SL SDAP Data PDU format with SDAP header for unicast of NR sidelink communication
6.2.3 End-Marker Control PDU
Figure 6.2.3-1 shows the format of End-Marker Control PDU.
Figure 6.2.3-1: End-Marker Control PDU
6.3 Parameters
6.3.1 General
If not otherwise mentioned in the definition of each field, then the bits in the parameters shall be interpreted as follows: the left most bit is the first and most significant bit and the right most bit is the last and least significant bit.
Unless otherwise mentioned, integers are encoded in standard binary encoding for unsigned integers. In all cases the bits appear ordered from MSB to LSB when read in the PDU.
6.3.2 Data
Length: Variable
This field includes the SDAP SDU.
6.3.3 D/C
Length: 1 bit,
The D/C bit indicates whether the SDAP PDU is an SDAP Data PDU or an SDAP Control PDU.
Table 6.3.3-1: D/C field
|
Bit |
Description |
|
0 |
Control PDU |
|
1 |
Data PDU |
6.3.4 QFI
Length: 6 bits
The QFI field indicates the ID of the QoS flow (TS 23.501 [4]) to which the SDAP PDU belongs.
6.3.5 R
Length: 1 bit
Reserved. In this version of the specification reserved bits shall be set to 0. Reserved bits shall be ignored by the receiver.
6.3.6 RQI
Length: 1 bit,
The RQI bit indicates whether NAS should be informed of the updated of SDF to QoS flow mapping rules (TS 23.501 [4]).
Table 6.3.6-1: RQI field
|
Bit |
Description |
|
0 |
No action |
|
1 |
To inform NAS that RQI bit is set to 1. |
6.3.7 RDI
Length: 1 bit,
The RDI bit indicates whether QoS flow to DRB mapping rule should be updated.
Table 6.3.7-1: RDI field
|
Bit |
Description |
|
0 |
No action |
|
1 |
To store QoS flow to DRB mapping rule. |
6.3.8 PQFI
Length: 6 bits
The PQFI field indicates the ID of the PC5 QoS flow (as specified in TS 24.587[6]) to which the SDAP PDU belongs.
Annex A (informative):
Change history
|
Change history |
|||||||
|
Date |
Meeting |
TDoc |
CR |
Rev |
Cat |
Subject/Comment |
New version |
|
06/2017 |
RAN2 NR AH |
– |
– |
– |
First version |
0.1.0 |
|
|
08/2017 |
RAN2#99 |
– |
– |
– |
To capture agreements made in RAN2#99 |
0.2.0 |
|
|
09/2017 |
RAN#77 |
– |
– |
– |
Presented to RAN#77 for information |
1.0.0 |
|
|
10/2017 |
RAN2#99bis |
To capture agreements made in RAN2#99bis |
1.1.0 |
||||
|
11/2017 |
RAN2#100 |
To remove editor’s notes. |
1.2.0 |
||||
|
01/2018 |
RAN2 NR AH |
To capture agreements made in RAN2 NR AH |
1.3.0 |
||||
|
04/2018 |
RAN2#101bis |
To capture agreements made in RAN2#101 |
1.4.0 |
||||
|
RAN2#101bis |
To capture agreements made in RAN2#101bis |
1.5.0 |
|||||
|
05/2018 |
RAN2#102 |
To capture agreements made in RAN2#102 |
1.6.0 |
||||
|
06/2018 |
RP-80 |
RP-181256 |
Provided to RAN #80 for approval |
2.0.1 |
|||
|
RP-80 |
RP-181266 |
Provided to RAN #80 for approval (update as RP-181256 was misused for another Tdoc) |
2.0.2 |
||||
|
Upgraded to Rel-15 after the plenary approval |
15.0.0 |
||||||
|
09/2018 |
RP-81 |
RP-181940 |
0006 |
1 |
F |
Miscellaneous corrections for SDAP |
15.1.0 |
|
RP-81 |
RP-181939 |
0007 |
– |
D |
Miscellaneous corrections to SDAP |
15.1.0 |
|
|
RP-81 |
RP-181942 |
0008 |
1 |
F |
Correction on flow remapping from default DRB |
15.1.0 |
|
|
03/2020 |
RP-87 |
RP-200346 |
0014 |
1 |
B |
Introduction of 5G_V2X_NRSL to 37.324 |
16.0.0 |
|
07/2020 |
RP-88 |
RP-201176 |
0016 |
1 |
F |
Capture latest agreements on SDAP |
16.1.0 |
|
09/2020 |
RP-89 |
RP-201927 |
0019 |
– |
F |
37.324 corrections on Sidelink |
16.2.0 |
|
06/2021 |
RP-92 |
RP-211470 |
0020 |
2 |
F |
Correction of PQFI terminology in SDAP |
16.3.0 |
|
03/2022 |
RP-95 |
RP-220484 |
0022 |
1 |
B |
Introduction of NR MBS |
17.0.0 |