B.2 UDC packet format and parameters
38.3233GPPNRPacket Data Convergence Protocol (PDCP) specificationRelease 17TS
B.2.1 UDC Header and UDC Data Block format
Figure B.2.1-1 shows the format of UDC Header and UDC Data Block.
Figure B.2.1-1: UDC header and UDC data block format
B.2.2 UDC parameters
B.2.2.1 FU
Length: 1 bit
Indication of whether this packet is compressed by UDC protocol or not. Value ‘1’ means the packet is compressed by UDC protocol.
Table B.2.2.1-1: FU field
|
Bit |
Description |
|
0 |
Packet is not compressed using UDC protocol |
|
1 |
Packet is compressed using UDC protocol |
B.2.2.2 FR
Length: 1 bit
Indication of whether UDC compression buffer is reset or not. Value ‘1’ means this is the first compressed packet after UDC buffer reset.
Table B.2.2.2-1: FR field
|
Bit |
Description |
|
0 |
Compression buffer is not reset. |
|
1 |
Compression buffer has been reset. |
B.2.2.3 Checksum
Length: 4 bits
This field contains the validation bits for the compression buffer content: The checksum is calculated by the content of current compression buffer before the current packet is put into buffer.
The checksum is derived from the values of the first 4 bytes and the last 4 bytes in the whole compression buffer. The calculation is described as follows:
– Each byte is divided into two 4-bit numbers.
– The 16 4-bit numbers are added together to obtain a sum;
– The checksum is one’s complement of the right-most 4 bits (i.e. 4 LSB) of the sum.
An example of checksum calculation is shown in Annex B.2.3.
B.2.3 An example of UDC Checksum calculation
The current UDC compression/decompression buffer has the following binary values for example:
Header <1,1,0,0,0,1,0,1,0,0,1,1,1,1,1,1,0,0,0,1,1,0,0,1,0,1,0,1,0,0,0,1, ……, 0,1,1,1,1,1,0,1,1,0,0,0,1,0,1,0,1,0,0,1,1,1,1,1,1,0,0,1,1,1,0,0> Tail
The sum of the first 4 bytes and the last 4 bytes can be calculated:
1100+0101+0011+1111+0001+1001+0101+0001+0111+1101+1000+1010+1001+1111+1001+1100 = 10000110;
And checksum value will be one’s complement of the right-most 4 bits (i.e. 4 LSB) of the above sum. Hence checksum is 1001.
Annex C (informative):
Change history
|
Change history |
|||||||
|
Date |
Meeting |
TDoc |
CR |
Rev |
Cat |
Subject/Comment |
New Version |
|
2017.03 |
RAN2#97bis |
R2-1703512 |
– |
– |
– |
First version. |
x.y.z |
|
2017.04 |
RAN2#97bis |
R2-1703916 |
– |
– |
– |
Change clause name "Retransmission" to "Data recovery" |
0.0.1 |
|
2017.05 |
RAN2#98 |
R2-1704076 |
– |
– |
– |
Initial draft TS capturing outcome of e-mail discussion [97bis#24] |
0.0.5 |
|
2017.06 |
RAN2 NR AH |
R2-1706868 |
– |
– |
– |
Capture agreements made in RAN2#98 |
0.1.0 |
|
2017.08 |
RAN2 NR AH |
R2-1707507 |
– |
– |
– |
Capture agreements made in RAN2 NR AH#2 |
0.2.0 |
|
2017.08 |
RAN2#99 |
R2-1709097 |
– |
– |
– |
Adding integrity protection in section 5.1.2 |
0.2.1 |
|
2017.08 |
RAN2#99 |
R2-1709753 |
– |
– |
– |
Capture agreements made in RAN2#99 |
0.3.0 |
|
2017.09 |
RANP#77 |
RP-171993 |
– |
– |
– |
Provided for information to RAN |
1.0.0 |
|
2017.10 |
RAN2#99bis |
R2-1713660 |
– |
– |
– |
Capture agreements made in RAN2#99bis |
1.0.1 |
|
2017.11 |
RAN2#100 |
R2-1714273 |
– |
– |
– |
Capture agreements made in RAN2#100 |
1.1.0 |
|
2017.12 |
RP-78 |
RP-172335 |
– |
– |
– |
Provided for approval to RAN |
2.0.0 |
|
2017/12 |
RP-78 |
Upgraded to Rel-15 (MCC) |
15.0.0 |
||||
|
2018/03 |
RP-79 |
RP-180440 |
0002 |
1 |
F |
Corrections to PDCP specification |
15.1.0 |
|
2018/06 |
RP-80 |
RP-181215 |
0006 |
3 |
F |
Corrections to PDCP specification |
15.2.0 |
|
RP-80 |
RP-181215 |
0009 |
1 |
B |
Introduction of PDCP duplication |
15.2.0 |
|
|
2018/09 |
RP-81 |
RP-181942 |
0011 |
4 |
F |
Clarification on PDCP transmission |
15.3.0 |
|
2018/12 |
RP-82 |
RP-182650 |
0022 |
1 |
F |
Suspend and resume of security |
15.4.0 |
|
RP-82 |
RP-182655 |
0023 |
– |
F |
Introducing PDCP suspend procedure |
15.4.0 |
|
|
RP-82 |
RP-182656 |
0024 |
– |
F |
Clarification on ciphering MAC-I |
15.4.0 |
|
|
2019/03 |
RP-83 |
RP-190544 |
0025 |
2 |
F |
Correction on the PDCP re-establishment for AM DRB |
15.5.0 |
|
RP-83 |
RP-190540 |
0027 |
1 |
F |
Correction on PDCP SN length |
15.5.0 |
|
|
2019/06 |
RP-84 |
RP-191375 |
0031 |
1 |
F |
PDCP association with RLC for RBs configured with PDCP duplication |
15.6.0 |
|
2020/03 |
RP-87 |
RP-200346 |
0038 |
2 |
B |
38.323 CR for NR V2X |
16.0.0 |
|
RP-87 |
RP-200352 |
0039 |
3 |
B |
Introduction of NR IIOT |
16.0.0 |
|
|
RP-87 |
RP-200347 |
0042 |
2 |
B |
Introduction of DAPS handover |
16.0.0 |
|
|
2020/07 |
RP-88 |
RP-201190 |
0032 |
6 |
F |
PDCP security issue about duplicate detection |
16.1.0 |
|
RP-88 |
RP-201195 |
0045 |
3 |
C |
CR on 38.323 for NR mobility enhancement |
16.1.0 |
|
|
RP-88 |
RP-201176 |
0048 |
1 |
F |
38.323 CR for NR V2X |
16.1.0 |
|
|
RP-88 |
RP-201181 |
0049 |
1 |
F |
NR PDCP corrections for NR IIOT |
16.1.0 |
|
|
2020/09 |
RP-89 |
RP-201963 |
0050 |
2 |
F |
Correction on receive operation when both EHC and out-of-order delivery are configured for a DRB |
16.2.0 |
|
RP-89 |
RP-201932 |
0052 |
1 |
F |
PDCP entity associated with AM RLC entity |
16.2.0 |
|
|
RP-89 |
RP-201927 |
0056 |
– |
F |
38.323 corrections on Sidelink |
16.2.0 |
|
|
2021/03 |
RP-91 |
RP-210692 |
0064 |
1 |
F |
Correction on PDCP transmit operation |
16.3.0 |
|
2021/06 |
RP-92 |
RP-211485 |
0074 |
1 |
A |
Correction on suspended AM DRB in PDCP re-establishment |
16.4.0 |
|
RP-92 |
RP-211470 |
0078 |
1 |
F |
PDCP miscellaneous corrections |
16.4.0 |
|
|
2021/09 |
RP-93 |
RP-212442 |
0080 |
1 |
F |
CR for the ciphering of EHC header |
16.5.0 |
|
2021/12 |
RP-94 |
RP-213342 |
0082 |
1 |
F |
Correction to Window_Size for SLRB |
16.6.0 |
|
2022/03 |
RP-95 |
RP-220495 |
0085 |
1 |
B |
Introducing support of UP IP for EPC connected architectures using NR PDCP |
17.0.0 |
|
RP-95 |
RP-220491 |
0086 |
2 |
B |
Introduction of SL Relay in 38.323 |
17.0.0 |
|
|
RP-95 |
RP-220489 |
0087 |
1 |
B |
Introduction of the support for UDC in NR |
17.0.0 |
|
|
RP-95 |
RP-220484 |
0088 |
– |
B |
Introduction of NR MBS into 38.323 |
17.0.0 |
|
|
2022/06 |
RP-96 |
RP-221712 |
0092 |
– |
A |
Correction on PDCP SN setting for SLRB transmit operation |
17.1.0 |
|
RP-96 |
RP-221732 |
0093 |
1 |
F |
Correction on PDCP for SL relay |
17.1.0 |
|
|
RP-96 |
RP-221731 |
0094 |
1 |
F |
Corrections to UDC |
17.1.0 |
|
|
RP-96 |
RP-221712 |
0095 |
– |
A |
Corrections on receiving PDCP entity establishment for SL-SRB0/SL-SRB1 |
17.1.0 |
|
|
RP-96 |
RP-221754 |
0096 |
– |
F |
PDCP Corrections for MBS |
17.1.0 |
|
|
2022/09 |
RP-97 |
RP-222524 |
0097 |
1 |
F |
Correction on PDCP for L2 U2N Relay |
17.2.0 |
|
RP-97 |
RP-222523 |
0098 |
1 |
F |
Corrections for MBS 38.323 |
17.2.0 |
|