# US 10,484,991 B2 · User terminal, radio base station and radio communication method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,484,991 B2 - Document ID: US10484991B2 - Status: Granted - Kind: B2 - Application number: 15/753,686 - Filed: 2016-08-19 - Published: 2019-01-10 - Granted: 2019-11-19 - Earliest claimed: 2015-08-21 - Assignees: Ntt Docomo, Inc. - Applicants: Ntt Docomo, Inc. - Inventors: Kazuaki Takeda; Hiroki Harada; Satoshi Nagata - Web page: https://patentgrep.com/patent/US10484991B2 ## CPC - H04W 72/0453: Resources in frequency domain, e.g. a carrier in FDMA - H04W 28/0215: {based on user or device properties, e.g. MTC-capable devices (services for machine-to-machine communication [M2M] or machine type communication [MTC] H04W4/70; wireless resource selection or allocation plan definition based on terminal or device properties H04W72/51)} - H04W 56/00: Synchronisation arrangements - H04W 56/0015: {one node acting as a reference for the others} - H04W 72/04: Wireless resource allocation - H04W 72/51: based on terminal or device properties - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract The present invention is designed so that synchronization can be adequately established even when a band to use is limited to a narrow band than the minimum system bandwidth (1.4 MHz) that is supported in existing LTE. According to one aspect of the present invention, a user terminal, in which a band to use is limited to a narrower band than the minimum system bandwidth supported in an existing LTE (Long Term Evolution) system, has a receiving section that receives a signal that is divided into a plurality of periods and transmitted, in a predetermined narrow band that overlaps a frequency band in which an existing synchronization signal is transmitted, and a control section that performs a synchronization process by identifying the signal that is divided into the plurality of periods and transmitted as being a synchronization signal that is generated by using a predetermined sequence, wherein the signal that is transmitted in at least one period in the plurality of periods is a portion of the existing synchronization signal. ## Claims ### Claim 1 A user terminal, in which a band to use is limited to a narrower band than a minimum system bandwidth supported in an existing LTE (Long Term Evolution) system, the user terminal comprising: a receiving section that receives a signal that is divided into a plurality of periods and transmitted, in a predetermined narrow band that overlaps a frequency band in which an existing synchronization signal is transmitted; and a control section that performs a synchronization process by identifying the signal that is divided into the plurality of periods and transmitted as being a synchronization signal that is generated by using a predetermined sequence, wherein a signal that is transmitted in at least one period in the plurality of periods is a portion of the existing synchronization signal, the portion being mapped to the predetermined narrow band. ### Claim 2 (depends on 1) The user terminal according to claim 1, wherein a length of the predetermined sequence is shorter than a length of a sequence that is used to generate the existing synchronization signal. ### Claim 3 (depends on 1) The user terminal according to claim 1, wherein the predetermined sequence is a sequence that is given by puncturing the sequence that is used to generate the existing synchronization signal. ### Claim 4 (depends on 1) The user terminal according to claim 1, wherein, after the synchronization process in the control section is complete, the receiving section receives another synchronization signal and/or reference signal in a narrow band that is at least partly different from the predetermined narrow band. ### Claim 5 (depends on 4) The user terminal according to claim 4, wherein the receiving section identifies the narrow band that is at least partly different from the predetermined narrow band based on the synchronization signal that is generated by using the predetermined sequence. ### Claim 6 (depends on 1) The user terminal according to claim 1, wherein the predetermined narrow band does not overlap a center frequency of the minimum system bandwidth. ### Claim 7 (depends on 1) The user terminal according to claim 1, wherein the predetermined narrow band overlaps a channel raster of a predetermined interval. ### Claim 8 (depends on 7) The user terminal according to claim 7, wherein the predetermined narrow band overlaps one of frequency locations that are provided at intervals of a least common multiple of the channel raster of a 100-kHz interval and a resource block size of 180 kHz. ### Claim 9 A radio base station that communicates with a user terminal, in which a band to use is limited to a narrower band than a minimum system bandwidth supported in an existing LTE (Long Term Evolution) system, the radio base station comprising: a generating section that generates a synchronization signal by using a predetermined sequence; and a transmission section that transmits the synchronization signal, by dividing the synchronization signal into a plurality of periods, in a predetermined narrow band that overlaps a frequency band in which an existing synchronization signal is transmitted, wherein the transmission section transmits the existing synchronization signal, which includes a divided portion of the synchronization signal, in at least one period in the plurality of periods, the portion being mapped to the predetermined narrow band. ### Claim 10 A radio communication method for a user terminal, in which a band to use is limited to a narrower band than a minimum system bandwidth supported in an existing LTE (Long Term Evolution) system, the radio communication method comprising the steps of: receiving a signal that is divided into a plurality of periods and transmitted, in a predetermined narrow band that overlaps a frequency band in which an existing synchronization signal is transmitted; and performing a synchronization process by identifying the signal that is divided into the plurality of periods and transmitted as being a synchronization signal that is generated by using a predetermined sequence, wherein a signal that is transmitted in at least one period in the plurality of periods is a portion of the existing synchronization signal, the portion being mapped to the predetermined narrow band.