Method and apparatus for device-to-device sidelink resource selection in a wireless communication system

A method of a first device performing sidelink transmission in a sidelink resource pool, comprising:

• the first device has a configuration of the sidelink resource pool, wherein the sidelink resource pool is enabled with resource reservation for different Transport Blocks (TBs);
• the first device has a configuration of a list of reserved periods;
• the first device selects or determines a first reserved period from the list of reserved periods;
• the first device randomly selects a first integer in a first interval, wherein the first interval is starting at a first integer number times a scaling factor and ending at a second integer number times the scaling factor, and the scaling factor is derived based on a third value different from the value of the first reserved period, and wherein the first integer is used for deriving or determining a number of transmission opportunities of different TBs with the first reserved period;
• and
• the first device performs sidelink transmission on one transmission opportunity from the number of transmission opportunities.

A first device for performing sidelink transmission in a sidelink resource pool, 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:
• have a configuration of the sidelink resource pool, wherein the sidelink resource pool is enabled with resource reservation for different Transport Blocks (TBs);
• have a configuration of a list of reserved periods;
• select or determine a first reserved period from the list of reserved periods, wherein the first selected or determined reserved period is within a first set of reserved periods;
• select randomly a first integer in a first interval, wherein the first interval is starting at a first integer number times a scaling factor and ending at a second integer number times the scaling factor, and the scaling factor is derived based on a largest reserved period in the first set of reserved periods, and wherein the first integer is used for deriving or determining a number of transmission opportunities of different TBs with the first reserved period;
• and
• perform sidelink transmission on one transmission opportunity from the number of transmission opportunities.