# US 2017/0289937 A1 · Base station and user terminal > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0289937 A1 - Document ID: US20170289937A1 - Status: Published application - Kind: A1 - Application number: 15/511,305 - Filed: 2015-09-16 - Published: 2017-10-05 - Earliest claimed: 2014-09-26 - Assignees: KYOCERA Corporation - Applicants: Kyocera Corporation - Inventors: Hiroyuki URABAYASHI; Chiharu YAMAZAKI; Naohisa MATSUMOTO; Noriyoshi FUKUTA; Kugo MORITA; Masato FUJISHIRO - Web page: https://patentgrep.com/patent/US20170289937A1 ## CPC - H04W 56/001: {Synchronization between nodes} - H04W 16/14: Spectrum sharing arrangements {between different networks} - H04W 48/16: Discovering, processing access restriction or access information - H04W 56/00: Synchronisation arrangements - H04W 56/0015: {one node acting as a reference for the others} - H04W 56/0025: {synchronizing potentially movable access points} - H04W 72/04: Wireless resource allocation - H04W 88/02: Terminal devices - H04W 88/08: Access point devices - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A base station manages a first cell and a second cell and communicates with a user terminal by carrier aggregation which is applied to the first cell and the second cell, the first cell being allocated a licensed band requiring a license and a second cell being allocated an unlicensed band not requiring a license. The base station includes: a transmitter configured to transmit a synchronization signal used for synchronization between the second cell and the user terminal, by at least one carrier selected from the unlicensed band based on a result of carrier sensing in the second cell; and a controller configured to instruct the user terminal to perform a detection operation of the synchronization signal for all or part of the carrier through the first cell. ## Claims ### Claim 1 A base station which manages a first cell and a second cell and communicates with a user terminal by carrier aggregation which is applied to the first cell and the second cell, the first cell being allocated a licensed band requiring a license and a second cell being allocated an unlicensed band not requiring a license, the base station comprising: a transmitter configured to transmit a synchronization signal used for synchronization between the second cell and the user terminal, by at least one carrier selected from the unlicensed band based on a result of carrier sensing in the second cell; and a controller configured to instruct the user terminal to perform a detection operation of the synchronization signal for all or part of the carrier through the first cell. ### Claim 2 (depends on 1) The base station according to claim 1, wherein the transmitter is configured to transmit configuration information of the second cell to the user terminal through the first cell, based on a detection report indicating a result of the detection operation from the user terminal, the configuration information including a carrier available for the carrier aggregation among the carriers. ### Claim 3 (depends on 1) The base station according to claim 1, further comprising a carrier sense controller configured to determine whether the carrier sensing is performed, based on a radio resource status of the first cell. ### Claim 4 (depends on 1) The base station according to claim 1, wherein the controller is configured to receive the detection report indicating the result of the detection operation from the user terminal and thereafter, provide the user terminal with a carrier sense instruction for a carrier specified based on the detection report. ### Claim 5 A user terminal which communicates with a base station by carrier aggregation which is applied to a first cell and a second cell, the base station managing the first cell allocated a licensed band requiring a license and the second cell allocated an unlicensed band not requiring a license, the user terminal comprising: a controller configured to perform a detection operation of a synchronization signal on all or part of the carrier, based on an instruction for the detection operation of the synchronization signal used for synchronization with the second cell, which is transmitted by at least one carrier among the unlicensed band, the instruction being performed from the base station through the first cell; and a transmitter configured to transmit a detection report indicating a result of the detection operation to the base station through the first cell. ### Claim 6 (depends on 5) The user terminal according to claim 5, further comprising a carrier sense controller configured to perform carrier sensing on the carrier specified by the instruction, based on a carrier sense instruction performed by the base station through the first cell. ### Claim 7 A base station which manages a first cell and a second cell and communicates with a user terminal by carrier aggregation which is applied to the first cell and the second cell, the first cell being allocated a licensed band requiring a license and a second cell being allocated an unlicensed band not requiring a license, the base station comprising: a transmitter configured to transmit at least one carrier of the unlicensed band, a temporal timing in the carrier, and configuration information of the second cell to the user terminal through the first cell, the at least one carrier being determined based on a result of carrier sensing in the second cell. ### Claim 8 (depends on 7) The base station according to claim 7, wherein the transmitter is configured to transmit a synchronization signal used for synchronization between the second cell and the user terminal and user data in the same subframe by the carrier in a time division manner. ### Claim 9 (depends on 7) The base station according to claim 7, wherein the transmitter is configured to transmit a synchronization signal used for synchronization between the second cell and the user terminal, user data, and the reservation channel including a length of a subframe occupying the unlicensed band in a host station, in the same subframe by the carrier in a time division manner. ### Claim 10 (depends on 7) The base station according to claim 7, wherein the transmitter is configured to transmit a random access preamble transmission instruction to the user terminal through the first cell, the random access preamble transmission instruction including preamble sequence configuration information for the second cell along with the temporal timing and the configuration information of the second cell. ### Claim 11 A user terminal which communicates with a base station by carrier aggregation which is applied to a first cell and a second cell, the base station managing the first cell allocated a licensed band requiring a license and the second cell allocated an unlicensed band not requiring a license, the user terminal comprising: a receiver configured to receive at least one carrier of the unlicensed band, which is determined based on a result of carrier sensing in the second cell, a temporal timing in the carrier, and configuration information of the second cell, the result of carrier sensing being received from the base station through the first cell. ### Claim 12 (depends on 11) The user terminal according to claim 11, wherein the receiver is configured to receive a random access preamble transmission instruction including the preamble sequence configuration information for the second cell along with the carrier, the temporal timing, and the configuration information of the second cell, which are transmitted from the base station through the first cell, and the user terminal further comprises a transmitter configured to transmit a random access preamble to the base station through the second cell in response to reception of the preamble transmission instruction.