Method and user equipment for performing random access procedure

• US 10,349,449 B2
• Filed: 10/26/2017
• Issued: 07/09/2019
• Est. Priority Date: 10/30/2016
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Hong, Jongwoo, Lee, Sunyoung, Yi, Seungjune
• Primary Examiner(s): Elhag, Magdi
• Application Number:
  US15/794,523
• Publication Number:
  US 20180124836A1
• Time in Patent Office: 621 Days
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/51 based on terminal or device properties
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 74/0866 using a dedicated channel for access

Abstract

In the present invention, a user equipment (UE) receives physical random access channel (PRACH) configuration information. The UE determines a part of PRACH resources among PRACH resources configured based on the PRACH configuration information, if a random access (RA) procedure is triggered. The UE performs the RA procedure using only the determined part of the PRACH resources. The PRACH configuration information includes a periodicity value N, expressed in number of configured PRACH resources. The determined part of PRACH resources are every N-th configured PRACH resource, starting from a specific PRACH resource for the RA procedure, among the PRACH resources configured based on the PRACH configuration information.

Claims

1. A method for performing, by a user equipment (UE), a random access (RA) procedure in a wireless communication system, the method comprising:

receiving, by the UE, physical random access channel (PRACH) configuration information;

determining, by the UE, a part of PRACH resources among PRACH resources configured based on the PRACH configuration information; and

performing, by the UE, the RA procedure using only the determined part of the PRACH resources,

wherein the PRACH configuration information includes a periodicity value N, expressed in number of configured PRACH resources,

wherein the determined part of PRACH resources are every N-th configured PRACH resource, starting from a starting PRACH resource for the RA procedure, among the PRACH resources configured based on the PRACH configuration information,

wherein the starting PRACH resource is a K-th configured PRACH resource after the RA procedure is triggered, and

wherein K=(an identity of the UE) modulo N.

2. The method according to claim 1,

wherein the starting PRACH resource is a configured PRACH resource occurring first after the RA procedure is triggered.

3. The method according to claim 1,

wherein the starting PRACH resource is determined based on the identity of the UE.

4. The method according to claim 1,

wherein N>

1.

5. The method according to claim 1,

wherein the UE is a narrowband internet of things (NB-IoT) UE.

6. The method according to claim 1,

wherein an RA preamble of the RA procedure is transmitted using only the determined part of the PRACH resources.

7. The method according to claim 1,

wherein the PRACH configuration information includes the periodicity value N for indicating time intervals at which the PRACH resources are configured based on the PRACH configuration information and information on when the configured PRACH resources start.

8. A user equipment (UE) for performing a random access (RA) procedure in a wireless communication system, the UE comprising:

a transmitter and receiver, and

a processor, operatively coupled to the transmitter and receiver, wherein the processor is configured to;

control the receiver to receive physical random access channel (PRACH) configuration information;

determine a part of PRACH resources among PRACH resources configured based on the PRACH configuration information; and

perform the RA procedure using only the determined part of the PRACH resources,

wherein the PRACH configuration information includes a periodicity value N, expressed in number of configured PRACH resources,

wherein the determined part of PRACH resources are every N-th configured PRACH resource, starting from a starting PRACH resource for the RA procedure, among the PRACH resources configured based on the PRACH configuration information,

wherein the processor is configured to determine that a K-th configured PRACH resource after the RA procedure is triggered is the starting PRACH resource, and

wherein K=(an identity of the UE) modulo N.

9. The UE according to claim 8,

wherein the starting PRACH resource is a configured PRACH resource occurring first after the RA procedure is triggered.

10. The UE according to claim 8, wherein the processor is further configured to:

determine the starting PRACH resource based on the identity of the UE.

11. The UE according to claim 8,

wherein N>

1.

12. The UE according to claim 8,

wherein the UE is a narrowband internet of things (NB-IoT) UE.

13. The UE according to claim 8, wherein the processor is further configured to:

control the transmitter to transmit an RA preamble of the RA procedure using only the determined part of the PRACH resources.

14. The UE according to claim 8, wherein the PRACH configuration information includes the periodicity value N for indicating time intervals at which the PRACH resources are configured based on the PRACH configuration information and information on when the configured PRACH resources start.