Method and apparatus of source indication for sidelink transmission in a wireless communication system

A method of a receiving device to perform sidelink reception, comprising:

• the receiving device is configured or allocated with an identity;
• the receiving device receives a control information;
• the receiving device acquires a first part of a source identity from the control information;
• the receiving device decodes a data packet based on the control information;
• the receiving device acquires a second part of the source identity from the data packet;
• and
• the receiving device determines the source identity associated with the data packet, wherein the source identity comprises the first part of the source identity and the second part of the source identity.

A transmitting device, comprising:

• a control circuit;
• a processor installed in the control circuit;
• and
• a memory installed in the control circuit and operatively coupled to the processor, wherein the processor is configured to execute a program code stored in the memory to perform operations, the operations comprising:
• being configured or allocated with an identity of the transmitting device, wherein the identity of the transmitting device comprises a first part of the identity of the transmitting device and a second part of the identity of the transmitting device and wherein the identity of the transmitting device is a layer-2 identity of the transmitting device;
• generating a data packet for sidelink transmission, wherein the data packet comprises the second part of the identity of the transmitting device;
• generating a control information associated with the data packet, wherein the control information comprises the first part of the identity of the transmitting device;
• and
• transmitting:
• the control information comprising the first part of the identity of the transmitting device;
• and
• the data packet comprising the second part of the identity of the transmitting device.