US 10,342,050 B2
Method for performing a random access procedure in a carrier aggregation with at least one scell operating in an unlicensed spectrum and a device therefor
Sunyoung Lee, Seoul (KR); Seungjune Yi, Seoul (KR); and Sangwon Kim, Seoul (KR)
Assigned to LG ELECTRONICS INC., Seoul (KR)
Appl. No. 15/565,117
Filed by LG ELECTRONICS INC., Seoul (KR)
PCT Filed Mar. 31, 2016, PCT No. PCT/KR2016/003342
§ 371(c)(1), (2) Date Oct. 6, 2017,
PCT Pub. No. WO2016/163687, PCT Pub. Date Oct. 13, 2016.
Claims priority of provisional application 62/145,468, filed on Apr. 9, 2015.
Prior Publication US 2018/0098353 A1, Apr. 5, 2018
Int. Cl. H04W 74/08 (2009.01); H04L 5/00 (2006.01); H04W 56/00 (2009.01); H04W 4/08 (2009.01); H04W 72/04 (2009.01); H04W 72/12 (2009.01)
CPC H04W 74/085 (2013.01) [H04L 5/0053 (2013.01); H04L 5/0073 (2013.01); H04W 4/08 (2013.01); H04W 56/00 (2013.01); H04W 72/0446 (2013.01); H04W 72/1215 (2013.01); H04W 74/08 (2013.01); H04L 5/001 (2013.01); H04W 56/0005 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A method for a User Equipment (UE) operating in a wireless communication system, the method comprising:
configuring with a Timing Advance Group (TAG) to which at least two uplink (UL) cells belong;
receiving a Physical Downlink Control Channel (PDCCH) order from an eNodeB (eNB) on a downlink (DL) cell associated with a first UL cell in the TAG, wherein the PDCCH order triggers a random access procedure by informing a random access preamble;
determining whether the first UL cell is available for transmitting the random access preamble;
selecting one of the at least two UL cells which is available for transmitting the random access preamble if the first cell is determined as unavailable; and
transmitting the informed random access preamble on the selected one of the at least two UL cells,
wherein the first UL cell is determined as unavailable if it is occupied by other transmitters as a result of a Listen Before Talk (LBT) procedure.