US 11,743,787 B2
Handover management in communication systems using unlicensed frequency bands
Henry Chang, San Diego, CA (US); and Masato Fujishiro, Yokohama (JP)
Assigned to Kyocera Corporation, Kyoto (JP)
Appl. No. 17/262,139
Filed by Kyocera Corporation, Kyoto (JP)
PCT Filed Aug. 6, 2019, PCT No. PCT/US2019/045239
§ 371(c)(1), (2) Date Jan. 21, 2021,
PCT Pub. No. WO2020/033364, PCT Pub. Date Feb. 13, 2020.
Claims priority of provisional application 62/716,713, filed on Aug. 9, 2018.
Prior Publication US 2021/0352547 A1, Nov. 11, 2021
Int. Cl. H04W 36/00 (2009.01); H04W 36/30 (2009.01); H04W 76/27 (2018.01); H04W 36/08 (2009.01)
CPC H04W 36/00837 (2018.08) [H04W 36/0079 (2018.08); H04W 36/08 (2013.01); H04W 36/30 (2013.01); H04W 76/27 (2018.02)] 10 Claims
OG exemplary drawing
 
1. A method performed at a communication device, the method comprising:
receiving, from a serving gNB, measurement report trigger information indicative of criteria for sending a measurement report, the criteria comprising:
a measurement report trigger threshold indicative of at least one of a minimum received signal strength threshold and a minimum received signal quality threshold;
a measurement report trigger validity period indicative of a time period that the measurement report trigger threshold is valid, the time period from receipt of the measurement report trigger information; and
a threshold offset value indicative of a maximum offset below the measurement report trigger threshold after expiration of the measurement report trigger validity period;
evaluating a channel occupancy level of an unlicensed channel to the serving gNB; and
transmitting, if the channel occupancy level is below a channel occupancy threshold and only if the criteria are met, a measurement report over the unlicensed channel to the serving gNB, the measurement report indicative of at least one of a received signal strength and a received signal quality at the communication device of at least one received signal transmitted from the target gNB;
receiving, from the serving gNB, a handover command with an inactivity indicator, the handover command identifying a handover procedure to a target gNB;
in response to failing the handover procedure at least partially as a result of another unlicensed channel to the target gNB being occupied, transitioning to a New Radio (NR) Radio Resource Control (RRC) Inactive state; and
executing an RRC Resume procedure to transition to the RRC Connected state to establish communication service with a new serving gNB located within a same Radio Access Network (RAN)-based Notification Area (RNA) as the serving gNB.