# US 2018/0323931 A1 · Base station, user apparatus, reference signal transmission method and signal reception method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0323931 A1 - Document ID: US20180323931A1 - Status: Published application - Kind: A1 - Application number: 15/774,110 - Filed: 2016-11-08 - Published: 2018-11-08 - Earliest claimed: 2015-11-10 - Assignees: Ntt Docomo, Inc. - Applicants: Ntt Docomo, Inc. - Inventors: Kohei Kiyoshima; Naoto Ookubo; Sadayuki Abeta; Satoshi Nagata; Hiroki Harada - Web page: https://patentgrep.com/patent/US20180323931A1 ## CPC - H04L 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal} - H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals} - H04W 56/001: {Synchronization between nodes} - H04W 72/04: Wireless resource allocation - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - 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 according to an embodiment is provided. The base station communicates with a user apparatus in an LTE-supported wireless communication system. The base station includes a generation unit configured to generate a signal in which a UE specific reference signal is mapped according to a first pattern in which, in a range of resource elements enclosed by a segment in the time direction indicated by a predetermined subframe in which a synchronization signal is mapped and by a segment in the frequency direction in which the synchronization signal is mapped, a UE specific reference signal is mapped onto a resource element other than a resource element onto which the synchronization signal is mapped; and a transmission unit configured to transmit the generated signal. ## Claims ### Claim 1 A base station that communicates with a user apparatus in an LTE-supported wireless communication system, the base station comprising: a generation unit configured to generate a signal in which a UE specific reference signal is mapped according to a first pattern in which, in a range of resource elements enclosed by a segment in the time direction indicated by a predetermined subframe in which a synchronization signal is mapped and by a segment in the frequency direction in which the synchronization signal is mapped, a UE specific reference signal is mapped onto a resource element other than a resource element onto which the synchronization signal is mapped; and a transmission unit configured to transmit the generated signal. ### Claim 2 (depends on 1) The base station according to claim 1, wherein the generation unit generates a signal in which a UE specific reference signal is mapped according to a second pattern different from the first pattern onto a resource element in a range enclosed by a segment in the time direction indicated by the predetermined subframe and a segment in the frequency direction in which the synchronization signal is not mapped. ### Claim 3 (depends on 1) The base station according to claim 1, wherein the generation unit generates a signal in which a specific reference signal is mapped according to the first pattern onto a resource element in a range enclosed by a segment in the time direction indicated by the predetermined subframe and a segment in the frequency direction in which the synchronization signal is not mapped. ### Claim 4 (depends on 3) The base station according to claim 3, wherein the generation unit generates a signal in which a UE specific reference signal is mapped according to the first pattern onto a resource element in a subframe in which a synchronization signal is not mapped in the time direction. ### Claim 5 (depends on 1) The base station according to claim 1, wherein the generation unit generates a signal in which a UE specific reference signal is mapped according to a second pattern different from the first pattern onto a resource element in a segment in the time direction indicated by the predetermined subframe in the case where a channel state information reference signal is mapped in a segment in the time direction indicated by the predetermined subframe. ### Claim 6 (depends on 1) The base station according to claim 1, further comprising: a management unit configured to transmit information indicating that a UE specific reference signal, which is mapped according to the first pattern, will be transmitted. ### Claim 7 A base station that communicates with a user apparatus in an LTE-supported wireless communication system, the base station comprising: a generation unit configured to generate a signal in which a UE specific reference signal is mapped according to a predetermined pattern onto resource elements in a range enclosed by a segment in the time direction indicated by a predetermined subframe in which a synchronization signal is mapped and by a segment in the frequency direction in which the synchronization signal is mapped, and, in the resource elements onto which a UE specific reference signal is mapped according to the predetermined pattern in the range, onto a resource element consecutive to a symbol onto which the synchronization signal is mapped, a physical downlink shared channel signal is mapped instead of a UE specific reference signal; and a transmission unit configured to transmit the generated signal. ### Claim 8 A user apparatus that communicates with a base station in an LTE-supported wireless communication system, the user apparatus comprising: a first reception unit configured to receive a UE specific reference signal mapped onto resource elements consecutive in the time direction in UE specific reference signals mapped according to a predetermined pattern onto resource elements in a range enclosed by a segment in the time direction indicated by a predetermined subframe in which a synchronization signal is mapped and a segment in the frequency direction in which the synchronization signal is mapped; and a second reception unit configured to receive a physical downlink shared channel signal by using the UE specific reference signal received by the first reception unit. ### Claim 9 A reference signal transmission method performed by a base station that communicates with a user apparatus in an LTE-supported wireless communication system, the reference signal transmission method comprising: generating a signal in which a UE specific reference signal is mapped according to a first pattern in which, in a range of resource elements enclosed by a segment in the time direction indicated by a predetermined subframe in which a synchronization signal is mapped and by a segment in the frequency direction in which the synchronization signal is mapped, a UE specific reference signal is mapped onto a resource element other than a resource element onto which the synchronization signal is mapped; and transmitting the generated signal. ### Claim 10 A signal reception method performed by a user apparatus that communicates with a base station in an LTE-supported wireless communication system, the signal reception method comprising: receiving, in UE specific reference signals mapped according to a predetermined pattern onto resource elements in a range enclosed by a segment in the time direction indicated by a predetermined subframe in which a synchronization signal is mapped and by a segment in the frequency direction in which the synchronization signal is mapped, a UE specific reference signal mapped onto resource elements consecutive in the time direction; and receiving a physical downlink shared channel signal by using the received UE specific reference signal. ### Claim 11 (depends on 2) The base station according to claim 2, wherein the generation unit generates a signal in which a UE specific reference signal is mapped according to a second pattern different from the first pattern onto a resource element in a segment in the time direction indicated by the predetermined subframe in the case where a channel state information reference signal is mapped in a segment in the time direction indicated by the predetermined subframe. ### Claim 12 (depends on 3) The base station according to claim 3, wherein the generation unit generates a signal in which a UE specific reference signal is mapped according to a second pattern different from the first pattern onto a resource element in a segment in the time direction indicated by the predetermined subframe in the case where a channel state information reference signal is mapped in a segment in the time direction indicated by the predetermined subframe. ### Claim 13 (depends on 4) The base station according to claim 4, wherein the generation unit generates a signal in which a UE specific reference signal is mapped according to a second pattern different from the first pattern onto a resource element in a segment in the time direction indicated by the predetermined subframe in the case where a channel state information reference signal is mapped in a segment in the time direction indicated by the predetermined subframe. ### Claim 14 (depends on 2) The base station according to claim 2, further comprising: a management unit configured to transmit information indicating that a UE specific reference signal, which is mapped according to the first pattern, will be transmitted. ### Claim 15 (depends on 3) The base station according to claim 3, further comprising: a management unit configured to transmit information indicating that a UE specific reference signal, which is mapped according to the first pattern, will be transmitted. ### Claim 16 (depends on 4) The base station according to claim 4, further comprising: a management unit configured to transmit information indicating that a UE specific reference signal, which is mapped according to the first pattern, will be transmitted. ### Claim 17 (depends on 5) The base station according to claim 5, further comprising: a management unit configured to transmit information indicating that a UE specific reference signal, which is mapped according to the first pattern, will be transmitted.