METHOD AND DEVICE FOR PERFORMING FAST FALLBACK IN ORDER TO AVOID LINK DISCONNECTION IN WIRELESS ACCESS SYSTEM SUPPORTING MILLIMETER WAVE (MMWAVE)

• US 20170272998A1
• Filed: 09/21/2015
• Published: 09/21/2017
• Est. Priority Date: 09/21/2014
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: CHOI, Kukheon, CHUNG, Jaehoon, HAHN, Genebeck, LEE, Eunjong, KIM, Jinmin, NOH, Kwangseok
• Granted Patent: US 10,313,950 B2
• Time in Patent Office: Days
• CPC Class Codes: H04W 36/0072 of resource information of target access point
• CPC Class Codes: H04W 36/0079 in case of hand-off failure or rejection
• CPC Class Codes: H04W 76/10 Connection setup

Abstract

The present invention relates to a wireless access system supporting a millimeter wave (mmWave), and provides methods for performing a fast fallback in order to avoid a link disconnection and devices supporting the same. As an embodiment of the present invention, a method for performing a fast fallback by a terminal in a wireless access system supporting a millimeter wave (mmWave) may comprise the steps of: establishing radio resource control (RRC) connections with a mmWave base station and a legacy base station, respectively; receiving downlink data transmitted from the mmWave base station; receiving, from the legacy base station, resource-related information associated with a resource to be allocated for a fast fallback; detecting whether a non-light of sight (NLoS) transition occurs in a mmWave link with the mmWave base station; and when the NLoS transition occurs, transmitting a fallback request message to the legacy base station in order to perform the fast fallback.

Claims

1-10. -10. (canceled)

11. A method of performing fast fallback at a user equipment (UE) in a wireless access system supporting millimeter wave (mmWave), the method comprising:

establishing a radio resource control (RRC) connection with an mmWave base station (BS) and a legacy BS;

receiving downlink data from the mmWave BS;

receiving resource related information related to resources to be allocated for fast fallback from the legacy BS;

detecting whether non-line of sight (NLoS) transition occurs in an mmWave link with the mmWave BS; and

transmitting a fallback request message in order to perform fast fallback to the legacy BS when NLoS transition occurs.

12. The method according to claim 11, wherein the resource related information includes a temporary cell identifier and downlink transmit power strength information of the legacy BS.

13. The method according to claim 12, wherein the resource related information further includes resource allocation information for allocating a resource region in which the fallback request message is transmitted.

14. The method according to claim 11, wherein the fallback request message includes sequence number (SN) status transfer information, UE-aggregate maximum bit rate (AMBR) information, UE security capability information and an access stratum (AS) security base key for the legacy BS.

15. The method according to claim 11, further comprising:

receiving downlink data from the legacy BS after performing fallback to the legacy BS,

wherein the UE continuously maintains the RRC connection with the mmWave BS even after fallback to the legacy BS.

16. A user equipment (UE) for performing fast fallback in a wireless access system supporting millimeter wave (mmWave), the UE comprising:

a transmission unit;

a reception unit; and

a processor functionally connected to the transmission unit and the reception unit to support fast fallback,

wherein the processor is configured to;

establish a radio resource control (RRC) connection with an mmWave base station (BS) and a legacy BS;

receive downlink data from the mmWave BS through the reception unit;

receive resource related information related to resources to be allocated for fast fallback from the legacy BS through the reception unit;

detect whether non-line of sight (NLoS) transition occurs in an mmWave link with the mmWave BS; and

transmit a fallback request message through the transmission unit in order to perform fast fallback to the legacy BS when NLoS transition occurs.

17. The UE according to claim 16, wherein the resource related information includes a temporary cell identifier and downlink transmit power strength information of the legacy BS.

18. The UE according to claim 17, wherein the resource related information further includes resource allocation information for allocating a resource region in which the fallback request message is transmitted.

19. The UE according to claim 16, wherein the fallback request message includes sequence number (SN) status transfer information, UE-aggregate maximum bit rate (AMBR) information, UE security capability information and access stratum (AS) security base key for the legacy BS.

20. The UE according to claim 16, wherein the processor is configured to receive downlink data from the legacy BS through the reception unit after performing fallback to the legacy BS,

wherein the UE continuously maintains the RRC connection with the mmWave BS even after fallback to the legacy BS.