Method for adjusting contention window size on basis of HARQ-ACK information in wireless access system supporting unlicensed band, and device for supporting same

• US 10,212,738 B2
• Filed: 05/12/2016
• Issued: 02/19/2019
• Est. Priority Date: 05/12/2015
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Seonwook, Ahn, Joonkui, Yang, Suckchel, Kim, Kijun, Kim, Byounghoon, Seo, Hanbyul, Park, Hanjun, Hwang, Daesung
• Primary Examiner(s): Mew, Kevin D
• Application Number:
  US15/573,435
• Publication Number:
  US 20180139779A1
• Time in Patent Office: 1,013 Days
• CPC Class Codes: H04L 1/00 Arrangements for detecting or preventing errors in the information received correcting synchronisation H04L7/00
• CPC Class Codes: H04L 1/18 Automatic repetition systems, e.g. Van Duuren systems
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 1/187 Details of sliding window management
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 5/00 Arrangements affording multiple use of the transmission path
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861
• CPC Class Codes: H04W 28/0289 Congestion control load shedding arrangements in network planning H04W16/08; performing reselection for handling the traffic H04W36/22; wireless traffic scheduling H04W72/12
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 74/085 collision avoidance
• CPC Class Codes: H04W 76/28 Discontinuous transmission [DTX]; Discontinuous reception [DRX]

Abstract

The present invention relates to a wireless access system that supports an unlicensed band, and provides various methods for adjusting a contention window size, methods for determining the time when the adjusted contention window size is applied, methods for distinguishing between a collision and a channel error, and devices for supporting the same. As an embodiment of the present invention, a method for adjusting a contention window size in a wireless access system supporting an unlicensed band may comprise the steps of: performing a channel access procedure; when it is determined through the performed channel access procedure that a serving cell (Scell) in the unlicensed band is in an idle state, transmitting a transmission burst including a downlink signal through the unlicensed band; receiving hybrid automatic repeat and request acknowledgment (HARQ-ACK) information corresponding to the transmission burst; and adjusting the CWS using the number of DTX states in the HARQ-ACK information when the transmission burst is scheduled in a self-carrier scheduling scheme.

Claims

1. A method for adjusting a contention window size (CWS) in a wireless access system supporting an unlicensed band, the method comprising:

performing a channel access procedure;

transmitting a transmission burst including a downlink signal in the unlicensed band, when it is determined as a result of the channel access procedure that a serving cell (SCell) of the unlicensed band is an idle state;

receiving hybrid automatic repeat and request acknowledgment (HARQ-ACK) information corresponding to the transmission burst; and

adjusting the CWS based on a number of discontinuous transmission (DTX) states in the HARQ-ACK information, when the transmission burst is scheduled by a self-carrier scheduling.

2. The method according to claim 1, wherein a DTX state is counted as a negative ACK (NACK) state for adjusting the CWS.

3. The method according to claim 2, wherein a NACK/DTX state and an ANY state in the HARQ-ACK information are also counted as the NACK state.

4. The method according to claim 1, wherein the DTX states in the HARQ-ACK information are not used for adjusting the CWS, when the transmission burst is scheduled by a cross-carrier scheduling.

5. The method according to claim 1, wherein the HARQ-ACK information used for adjusting the CWS is HARQ-ACK information corresponding to a first subframe of the transmission burst.

6. A transmission node configured to adjust a contention window size (CWS) in a wireless access system supporting an unlicensed band, the transmission node comprising:

a transmitter;

a receiver; and

a processor for supporting CWS adjustment,

wherein the processor controls the transmitter and the receiver in order to perform a channel access procedure, controls the transmitter to transmit a transmission burst including a downlink signal in the unlicensed band when it is determined as a result of the channel access procedure that a serving cell (SCell) of the unlicensed band is an idle state, controls the receiver to receive hybrid automatic repeat and request acknowledgment (HARQ-ACK) information corresponding to the transmission burst, and adjusts the CWS based on a number of discontinuous transmission (DTX) states in the HARQ-ACK information, when the transmission burst is scheduled by a self-carrier scheduling.

7. The transmission node according to claim 6, wherein a DTX state is counted as a negative ACK (NACK) state to adjust the CWS.

8. The transmission node according to claim 7, wherein a NACK/DTX state or an ANY state in the HARQ-ACK information is also counted as the NACK state.

9. The transmission node according to claim 6, wherein the DTX states in the HARQ-ACK information are not used for the CWS adjustment when the transmission burst is scheduled by a cross-carrier scheduling.

10. The transmission node according to claim 6, wherein the HARQ-ACK information used for the CWS adjustment is HARQ-ACK information corresponding to a first subframe of the transmission burst.