NR-V2X

Concepts

Sidelink Definition

The sidelink (SL) is used for communication between UEs, this is the link used for NR V2X.

NR sidelink will support: Unicast, groupcast and broadcast
- For unicast: HARQ feedback and HARQ combining are supported
- For groupcast: HARQ feedback and HARQ combining are supported
NR sidelink is expected to work in licensed and unlicensed bands
NR sidelink should be able to operate:
- Out of coverage
- Partial coverage
- In-coverage
NR supports SL transmissions in cell-specific UL resources
NR sidelink supports the same subcarrier spacings as Uu:
- FR1: 15, 30, 60 kHz
- FR2: 60, 120 kHz

The following physical channels are defined for NR sidelink:

S-SSB/PSBCH
- Carries information for NR sidelink synchronization and are periodically transmitted, it includes:
  - Sidelink PSS (S-PSS)
  - Sidelink SSS (S-SSS)
  - PSBCH

S-SSB time/frequency structure for Normal CP
S-SSB time/frequency structure for Extended CP
The S-SSB within the period of 160ms are distributed with the same interval with the following pre-configured parameters:
- N_offset: The offset from the start of the S-SSB period to the first S-SSB
- N_{_}interval: The interval between neighboring S-SSBs
Example of time/frequency structure for PSCCH, PSFCH and PSSCH Multiplexing.
For AGC purposes, 1st Sidelink symbol in a slot is a copy of 2nd Sidelink symbol of the slot, 2^nd SL symbol in the slot is used as starting symbol of PSSCH
Tx/Rx switching time means that a time is needed after a transmission until a UE is able to receive. A gap is needed at the end of the slot. One gap symbol is introduced after PSSCH transmission, one gap symbol is introduced after PSFCH transmission.