Apparatus and method of random access procedure
A communication method and system for converging a fifth generation (5G) communication system for supporting higher data rates beyond a fourth generation (4G) system with a technology for Internet of things (IoT) are provided. The communication method and system may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. A method for performing a random access procedure in a wireless communication system is provided.
1. A method performed by a terminal in a wireless communication system, the method comprising:
receiving, from a base station, information on a random access channel (RACH) configuration including first information on a number of preambles per a synchronization signal block (SSB) and second information on a start preamble index; and
identifying a set of preambles for a random access procedure associated with small data transmission (SDT) based on the first information and the second information.
2. The method of claim 1 , further comprising:
identifying whether a number of SSBs per physical random access channel (PRACH) occasion is smaller than 1,
wherein information on the number of the SSBs per PRACH occasion is included in the information on the RACH configuration.
3. The method of claim 2 ,
wherein, in case that the number of the SSBs per PRACH occasion Y is smaller than 1, the set of the preambles is identified based on the number of preambles X with consecutive indexes associated with a SSB index per valid PRACH occasion start from the start preamble index S.
4. The method of claim 2 ,
wherein, in case that the number of the SSBs per PRACH occasion Y is larger than or equal to 1, the set of the preambles is identified based on the number of preambles X with consecutive indexes associated with a SSB index n per valid PRACH occasion start from a n·N preamble total /Y+S preamble index, where S is the start preamble index, and N preamble total is a total number of preambles used for the random access procedure.
5. The method of claim 4 ,
wherein information on the total number of preambles used for the random access procedure is included in the information on the RACH configuration.
6. The method of claim 1 , further comprising:
selecting an SSB from at least one SSB received from the base station, the set of the preambles corresponding to the selected SSB;
selecting a preamble from the set of the preambles; and
transmitting, to the base station, the selected preamble to initiate the random access procedure.
7. The method of claim 1 , wherein a type of the random access procedure associated with the SDT is one of a 4-step random access procedure or a 2-step random access procedure.
8. A method performed by a base station in a wireless communication system, the method comprising:
transmitting, to a terminal, information on a random access channel (RACH) configuration including first information on a number of preambles per a synchronization signal block (SSB) and second information on a start preamble index; and
receiving, from the terminal, a preamble from a set of preambles for a random access procedure associated with small data transmission (SDT),
wherein the set of the preambles is identified based on the first information and the second information.
9. The method of claim 8 ,
wherein, in case that a number of SSBs per PRACH occasion Y is smaller than 1, the set of the preambles is identified based on the number of preambles X with consecutive indexes associated with a SSB index per valid PRACH occasion start from the start preamble index S.
10. The method of claim 8 ,
wherein, in case that a number of SSBs per PRACH occasion Y is larger than or equal to 1, the set of the preambles is identified based on the number of preambles X with consecutive indexes associated with a SSB index n per valid PRACH occasion start from a n·N preamble total /Y+S preamble index, where S is the start preamble index, and N preamble total is a total number of preambles used for the random access procedure.
11. A terminal in a wireless communication system, the terminal comprising:
a transceiver; and
a controller configured to:
control the transceiver to receive, from a base station, information on a random access channel (RACH) configuration including first information on a number of preambles per a synchronization signal block (SSB) and second information on a start preamble index, and
identify a set of preambles for a random access procedure associated with small data transmission (SDT) based on the first information and the second information.
12. The terminal of claim 11 ,
wherein the controller is further configured to identify whether a number of SSBs per physical random access channel (PRACH) occasion is smaller than 1, and
wherein information on the number of the SSBs per PRACH occasion is included in the information on the RACH configuration.
13. The terminal of claim 12 ,
wherein, in case that the number of the SSBs per PRACH occasion Y is smaller than 1, the set of the preambles is identified based on the number of preambles X with consecutive indexes associated with a SSB index per valid PRACH occasion start from the start preamble index S.
14. The terminal of claim 12 ,
wherein, in case that the number of the SSBs per PRACH occasion Y is larger than or equal to 1, the set of the preambles is identified based on the number of preambles X with consecutive indexes associated with a SSB index n per valid PRACH occasion start from a n·N preamble total /Y+S preamble index, where S is the start preamble index, and N preamble total is a total number of preambles used for the random access procedure.
15. The terminal of claim 14 ,
wherein information on the total number of preambles used for the random access procedure is included in the information on the RACH configuration.
16. The terminal of claim 11 ,
wherein the controller is further configured to select an SSB from at least one SSB received from the base station, the set of the preambles corresponding to the selected SSB, select a preamble from the set of the preambles, and control the transceiver to transmit, to the base station, the selected preamble to initiate the random access procedure.
17. The terminal of claim 11 , wherein a type of the random access procedure associated with the SDT is one of a 4-step random access procedure or a 2-step random access procedure.
18. A base station in a wireless communication system, the base station comprising:
a transceiver; and
a controller configured to:
control the transceiver to transmit, to a terminal, information on a random access channel (RACH) configuration including first information on a number of preambles per a synchronization signal block (SSB) and second information on a start preamble index, and
control the transceiver to receive, from the terminal, a preamble from a set of preambles for a random access procedure associated with small data transmission (SDT),
wherein the set of the preambles is identified based on the first information and the second information.
19. The base station of claim 18 ,
wherein, in case that a number of SSBs per PRACH occasion Y is smaller than 1, the set of the preambles is identified based on the number of preambles X with consecutive indexes associated with a SSB index per valid PRACH occasion start from the start preamble index S.
20. The base station of claim 18 ,
wherein, in case that a number of SSBs per PRACH occasion Y is larger than or equal to 1, the set of the preambles is identified based on the number of preambles X with consecutive indexes associated with a SSB index n per valid PRACH occasion start from a n·N preamble total /Y+S preamble index, where S is the start preamble index, and N preamble total is a total number of preambles used for the random access procedure.