Method for selecting of sidelink grant for a D2D UE in a D2D communication system and device therefor

1. A method for transmitting sidelink data by a User Equipment (UE) in a wireless communication system, the method comprising:

determining whether more sidelink data is available in a Sidelink Traffic Channel (STCH) than can be transmitted in a current Sidelink Control (SC) period; and

selecting a sidelink grant from a resource pool based on that more sidelink data is available in the STCH than can be transmitted in the current SC period,

wherein the sidelink grant is for a next SC period after the current SC period,

wherein the next SC period is a first available SC period which starts at least N time intervals after a time interval in which the sidelink grant was selected

where N is a positive integer, and

wherein the selected sidelink grant is considered to be a configured sidelink grant occurring in those time intervals starting at the beginning of the first available SC period.

2. The method according to claim 1 , further comprising:

receiving a resource pool configuration,

wherein the resource pool configuration includes information on the resource pool for the sidelink grant.

3. A User Equipment (UE) transmitting sidelink data in a wireless communication system, the UE comprising:

a transceiver; and

a processor configured to:

determine whether more sidelink data is available in a Sidelink Traffic Channel (STCH) than can be transmitted in a current Sidelink Control (SC) period, and

select a sidelink grant from a resource pool when more sidelink data is available in the STCH than can be transmitted in the current SC period,

wherein the sidelink grant is for a next SC period after the current SC period,

wherein the next SC period is a first available SC period which starts at least N time intervals after a time interval in which the sidelink grant was selected, and

wherein the selected sidelink grant is considered to be a configured sidelink grant occurring in those time intervals starting at the beginning of the first available SC period.

4. The UE according to claim 3 , wherein the processor is further configured to control the transceiver to receive a resource pool configuration, and

wherein the resource pool configuration includes information on the resource pool for the sidelink grant.

5. A device for performing sidelink communication in a wireless communication system, the device comprising:

at least one processor; and

at least one computer memory that is operably connectable to the at least one processor and that has stored thereon instructions which, when executed, cause the at least one processor to perform operations comprising:

determining whether more sidelink data is available in a Sidelink Traffic Channel (STCH) than can be transmitted in a current Sidelink Control (SC) period, and

selecting a sidelink grant from a resource pool when more sidelink data is available in the STCH than can be transmitted in the current SC period,

wherein the sidelink grant is for a next SC period after the current SC period,

wherein the next SC period is a first available SC period which starts at least N time intervals after a time interval in which the sidelink grant was selected

where N is a positive integer, and

wherein the selected sidelink grant is considered to be a configured sidelink grant occurring in those time intervals starting at the beginning of the first available SC period.

6. The device according to claim 5 , wherein the operations further comprising:

receiving a resource pool configuration,

wherein the resource pool configuration includes information on the resource pool for the sidelink grant.