Configuration and application of sidelink identification in wireless communication system

A method comprising:

• receiving, by a first wireless user device, a radio resource control (RRC) message indicating a sidelink (SL) identifier (ID) value;
• determining, based on a least significant bit (LSB) part of a layer-2 source ID, a layer-1 source ID;
• determining, based on a least significant bit (LSB) part of a layer-2 destination ID, a layer-1 destination ID;
• receiving, from a second wireless user device and based on the layer-1 destination ID, at least one data packet via a physical sidelink shared channel (PSSCH);
• generating an orthogonal sequence for a physical sidelink feedback channel (PSFCH) format, based on:
• the SL ID value;
• and
• the layer-1 source ID;
• and
• transmitting, to the second wireless user device and based on the orthogonal sequence, SL feedback control information (SFCI) via a PSFCH.