6 Protocol data units, formats, and parameters
38.3513GPPNRRelease 17Sidelink Relay Adaptation Protocol (SRAP) SpecificationTS
6.1 Protocol data units
6.1.1 Data PDU
The SRAP Data PDU is used to convey the following with or without the PDU header:
– upper layer data.
6.2 Formats
6.2.1 General
An SRAP Data PDU is a bit string that is byte aligned (i.e. multiple of 8 bits) in length. The formats of SRAP Data PDUs are described in clause 6.2.2 and their parameters are described in clause 6.3.
6.2.2 Data PDU
Figure 6.2.2-1 shows the format of the SRAP Data PDU with SRAP header being configured. This SRAP Data PDU format is applicable to SRAP SDU except those for SRB0 delivered over PC5 interface.
Figure 6.2.2-1: SRAP Data PDU format with SRAP header
Figure 6.2.2-2 shows the format of the SRAP Data PDU consisting only of a data field without any SRAP header. This SRAP Data PDU format is applicable to SRAP SDU for SRB0 delivered over PC5 interface.
Figure 6.2.2-2: SRAP Data PDU format without SRAP header
6.3 Parameters
6.3.1 General
If not otherwise mentioned in the definition of each field the bits in the parameters shall be interpreted as follows: the left most bit is the first and most significant 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 UE ID
Length: 8 bits.
This field carries local identity of U2N Remote UE.
6.3.3 BEARER ID
Length: 5 bits.
This field carries Uu radio bearer identity for U2N Remote UE.
6.3.4 Data
Length: Variable
This field carries the SRAP SDU (i.e. PDCP PDU or RRC PDU).
6.3.5 R
Length: 1 bit
Reserved. In this release, reserved bits shall be set to 0. Reserved bits shall be ignored by the receiver.
6.3.6 D/C
Length: 1 bit
This field indicates whether the corresponding SRAP PDU is an SRAP Data PDU or an SRAP Control PDU (not used in this release).
Table 6.3.6-1: D/C field
|
Bit |
Description |
|
0 |
SRAP Data PDU |
|
1 |
SRAP Control PDU (not used in this release) |
Annex A (informative):
Change history
|
Change history |
|||||||
|
Date |
Meeting |
TDoc |
CR |
Rev |
Cat |
Subject/Comment |
New version |
|
11/2021 |
RAN2#116 |
R2-2109400 |
Skeleton |
0.0.0 |
|||
|
11/2021 |
RAN2#116 |
R2-2111485 |
Skeleton update |
0.0.1 |
|||
|
11/2021 |
RAN2#116 |
R2-2111489 |
Capture the agreement till R2#116 |
0.1.0 |
|||
|
01/2022 |
RAN2#116bis |
R2-2200364 |
Capture the agreement till R2#116 that related to the 38.331 running CR |
0.2.0 |
|||
|
01/2022 |
RAN2#116bis |
R2-2201996 |
Capture the agreement during R2#116bis |
0.3.0 |
|||
|
02/2022 |
RAN2#117 |
R2-2202276 |
Capture the agreement till R2#116bis that related to the 38.331 running CR |
0.4.0 |
|||
|
02/2022 |
RAN2#117 |
R2-2203594 |
Capture the agreement during R2#117 |
0.5.0 |
|||
|
03/2022 |
RAN#95 |
RP-220794 |
Submit to RAN for approval |
1.0.0 |
|||
|
03/2022 |
RP-95 |
Upgraded to Rel-17 by MCC |
17.0.0 |
||||
|
06/2022 |
RP-96 |
RP-221732 |
0001 |
1 |
F |
Correction on SRAP for L2 UE-to-Network Relay |
17.1.0 |
|
09/2022 |
RP-97 |
RP-222524 |
0009 |
2 |
F |
Correction on SRAP for L2 U2N Relay |
17.2.0 |