Method and apparatus for transmitting RA preamble in NR system

Patent metadata

Field	Value
Publication number	US-10609736-B2
Application number	US-201815934140-A
Country	US
Kind code	B2
Filing date	Mar 23, 2018
Priority date	Mar 24, 2017
Publication date	Mar 31, 2020
Grant date	Mar 31, 2020

Abstract

A method and an apparatus for transmitting a message used to access a base station (BS) in a random access (RA) procedure by user equipment (UE) are provided. The method includes: determining a first RA preamble resource corresponding to an SSB index which corresponds to a transmission beam among a plurality of transmission beams of BS; and transmitting a message 1 of the RA procedure by using a first RA preamble format which includes the first RA preamble resource and at least one second RA preamble resource which neighbors the first RA preamble resource.

First claim

What is claimed is:

1. A method for transmitting, from a user equipment (UE) to a base station, a message 1 of a random access (RA) procedure, comprising:
determining a first RA preamble resource corresponding to an index of a synchronization signal block (SSB), wherein the SSB is received through one or more transmission beams among a plurality of transmission beams of the BS; and
transmitting the message 1 of the RA procedure by using a first RA preamble format through the first RA preamble resource and at least one second RA preamble resource which is adjacent to the first RA preamble resource, wherein the first RA preamble format includes the first RA preamble resource and the at least one second RA preamble resource.

2. The method of claim 1 ,
wherein an index of the at least one second RA preamble resource is i−1 or i+1 if an index of the first RA preamble resource is i.

3. The method of claim 1 ,
wherein a guard time (GT) period is allocated at an end of the first RA preamble resource and the at least one second RA preamble resource on a time axis.

4. The method of claim 1 ,
wherein the message 1 includes a cyclic prefix (CP) and a preamble sequence, and the preamble sequence includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols.

5. The method of claim 1 ,
wherein the first RA preamble format is a long RA preamble format or a short RA preamble format, and a time length of the long RA preamble format is an integer multiple of a time length of the short RA preamble format.

6. The method of claim 5 , wherein the transmitting the message 1 comprises
transmitting the message 1 by using the long RA preamble format if a coverage of a cell of the BS is relatively wide; or transmitting the message 1 by using the short RA preamble format if the coverage of the cell is relatively small.

7. The method of claim 1 , further comprising:
re-transmitting the message 1 by using a second RA preamble format having a longer time length than the first RA preamble format if the BS fails to receive the message 1.

8. The method of claim 1 , further comprising:
receiving a synchronization signal in the SSB through the plurality of transmission beams from the BS; and
measuring a reception strength of the plurality of transmission beams.

9. User equipment (UE) for transmitting a message 1 of a random access (RA) procedure, comprising:
a processor, a memory, and a radio frequency (RF) unit,
wherein the processor executes a program stored in the memory to perform:
determining a first RA preamble resource of which an index is the same as an index of a synchronization signal block (SSB), wherein the SSB is received through one or more transmission beams among a plurality of transmission beams of the BS; and
transmitting, by using the RF unit, the message 1 of the RA procedure by using a first RA preamble format through the first RA preamble resource and at least one second RA preamble resource which is adjacent to the first RA preamble resource, wherein the first RA preamble format includes the first RA preamble resource and the at least one second RA preamble resource.

10. The UE of claim 9 ,
wherein an index of the at least one second RA preamble resource is i−1 or i+1 if an index of the first RA preamble resource is i.

11. The UE of claim 9 ,
wherein a guard time (GT) period is allocated at an end of the first RA preamble resource and the at least one second RA preamble resource on a time axis.

12. The UE of claim 9 ,
wherein the message 1 includes a cyclic prefix (CP) and a preamble sequence, and the preamble sequence includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols.

13. The UE of claim 9 ,
wherein the first RA preamble format is a long RA preamble format or a short RA preamble format, and a time length of the long RA preamble format is an integer multiple of a time length of the short RA preamble format.

14. The UE of claim 13 ,
wherein when the transmitting of the message 1, the processor performs
transmitting, by using the RF unit, the message 1 by using the long RA preamble format if a coverage of a cell of the BS is relatively wide; or transmitting the message 1 by using the short RA preamble format if the coverage of the cell is relatively small.

15. The UE of claim 9 ,
wherein the processor executes the program to further perform
re-transmitting, by using the RF unit, the message 1 by using a second RA preamble format having a longer time length than the first RA preamble format if the BS fails to receive the message 1.

16. The UE of claim 9 ,
wherein the processor executes the program to further perform:
receiving, by using the RF unit, a synchronization signal in the SSB through the plurality of transmission beams from the BS; and
measuring the reception strength of the plurality of transmission beams.

17. A method for receiving a message 1 during a random access (RA) procedure from user equipment (UE), comprising:
transmitting a synchronization signal and a physical broadcasting channel (PBCH) through a plurality of transmission beams to the UE; and
receiving the message 1 through a first RA preamble resource and at least one second RA preamble resource being adjacent to the first RA preamble resource which are determined based on a reception strength of the plurality of transmission beams by performing a reception beam sweeping.

Assignees

• Electronics & Telecommunications Res Inst

Inventors

• Hui Bing
• Kim Il Gyu
• Kim Junhyeong
• Noh Gosan
• Chung Hee Sang
• Choi Sung Woo

Classifications

• H04W74/002

  Transmission of channel access control information · CPC title

• H04W88/08

  Access point devices · CPC title

• H04W4/70

  Services for machine-to-machine communication [M2M] or machine type communication [MTC] · CPC title

• H04W16/28

  using beam steering · CPC title

• H04L27/261

  Details of reference signals · CPC title