# US 2021/0243841 A1 · Terminal, base station, system, and feedback method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0243841 A1 - Document ID: US20210243841A1 - Status: Published application - Kind: A1 - Application number: 17/237,691 - Filed: 2021-04-22 - Published: 2021-08-05 - Earliest claimed: 2014-11-14 - Assignees: Ntt Docomo, Inc. - Applicants: Ntt Docomo, Inc. - Inventors: Shimpei Yasukawa; Kazuaki Takeda; Hiroki Harada; Satoshi Nagata; Qun Zhao - Web page: https://patentgrep.com/patent/US20210243841A1 ## CPC - H04W 92/18: between terminal devices - H04L 1/1864: {ARQ related signaling (H04L1/1607 takes precedence)} - H04L 1/1887: {Scheduling and prioritising arrangements} - H04L 1/189: {Transmission or retransmission of more than one copy of a message} - H04L 1/1896: {ARQ related signaling} - H04W 28/04: Error control - H04W 72/04: Wireless resource allocation - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A terminal is disclosed that includes a receiver that receives sidelink control information and data in sidelink and a transmitter that transmits a feedback signal corresponding to the data on a sidelink feedback channel. The transmitter determines a resource for transmitting the feedback signal based on a correspondence between a resource of the data and a resource for feedback. In other aspects, a base station, systems, and feedback methods are also disclosed. ## Claims ### Claim 1 A terminal comprising: a receiver that receives sidelink control information and data in sidelink; and a transmitter that transmits a feedback signal corresponding to the data on a sidelink feedback channel; wherein the transmitter determines a resource for transmitting the feedback signal based on a correspondence between a resource of the data and a resource for feedback. ### Claim 2 (depends on 1) The terminal according to claim 1, wherein the transmitter determines the resource for transmitting the feedback signal based on a correspondence between the sidelink control information and the resource for feedback. ### Claim 3 (depends on 1) The terminal according to claim 1, wherein, when the receiver receives the sidelink control information including a CSI request, the transmitter performs CSI reporting in sidelink. ### Claim 4 (depends on 3) The terminal according to claim 3, wherein the transmitter reports CQI or RI, as the CSI. ### Claim 5 (depends on 1) The terminal according to claim 1, wherein the receiver receives, from a base station, configuration information of a resource pool, the configuration information being configured with presence or absence of feedback. ### Claim 6 (depends on 1) The terminal according to claim 1, wherein, when the feedback signal only includes NACK, the transmitter transmits the feedback signal. ### Claim 7 (depends on 1) The terminal according to claim 1, wherein the receiver receives configuration information of a resource for sidelink feedback through RRC signaling. ### Claim 8 (depends on 1) The terminal according to claim 1, wherein a plurality of candidates for a resource for feedback transmission is determined, and the transmitter changes a resource used for feedback transmission depending on a content included in the sidelink control information. ### Claim 9 (depends on 2) The terminal according to claim 2, wherein the correspondence between the sidelink control information and the resource for feedback is preconfigured in the terminal. ### Claim 10 (depends on 1) The terminal according to claim 1, wherein the transmitter transmits a sequence multiplexed with the feedback signal. ### Claim 11 A terminal comprising: a transmitter that transmits sidelink control information and data in sidelink; and a receiver that receives a feedback signal for the data on a sidelink feedback channel, wherein the receiver receives the feedback signal on a resource determined based on a correspondence between a resource for the data and a resource for feedback. ### Claim 12 (depends on 11) The terminal according to claim 11, wherein the receiver receives the feedback signal on the resource determined based on a correspondence between the sidelink control information and the resource for feedback. ### Claim 13 (depends on 11) The terminal according to claim 11, wherein the transmitter transmits, based on the feedback signal received by the receiver, a feedback signal through a PUCCH. ### Claim 14 (depends on 11) The terminal according to claim 11, wherein the transmitter transmits a scheduling request to a base station, and sidelink transmission is performed using a resource assigned by the base station. ### Claim 15 (depends on 11) The terminal according to claim 11, wherein the receiver receives, from a base station, a DCI for sidelink scheduling, and the DCI includes a retransmission index, an NDI, and a feedback transmission resource indicator. ### Claim 16 A base station comprising: a receiver that receives a scheduling request from a terminal; and a transmitter that transmits, to the terminal, a DCI for sidelink scheduling, wherein the DCI includes a retransmission index, an NDI, and a feedback transmission resource indicator. ### Claim 17 A system comprising: a base station that includes a receiver that receives a scheduling request from a terminal, and a transmitter that transmits, to the terminal, a DCI for sidelink scheduling; and a terminal that includes a transmitter that performs sidelink transmission using a resource assigned by the DCI for the sidelink scheduling, wherein the DCI includes a retransmission index, an NDI, and a feedback transmission resource indicator. ### Claim 18 A system comprising: a first terminal that includes a receiver that receives sidelink control information and data in a sidelink, and a transmitter that transmits a feedback signal for the data on a sidelink feedback channel, wherein the transmitter determines a resource for transmitting the feedback signal based on a correspondence between a resource for the data and a resource for feedback; and a second terminal that includes a transmitter that transmits the sidelink control information and the data in the sidelink, and a receiver that receives the feedback signal for the data on the sidelink feedback channel, wherein the receiver receives the feedback signal on the resource determined based on the correspondence. ### Claim 19 A feedback method executed by a terminal, the method comprising: a receiving step of receiving sidelink control information and data in a sidelink; and a transmitting step of transmitting a feedback signal corresponding to the data on a sidelink feedback channel; wherein, in the transmitting step, a resource for transmitting the feedback signal is determined based on a correspondence between a resource of the data and a resource for feedback. ### Claim 20 A feedback method executed by a terminal, the method comprising: a transmitting step of transmitting sidelink control information and data in a sidelink; and a receiving step of receiving a feedback signal corresponding to the data on a sidelink feedback channel; wherein, in the receiving step, the feedback signal is received on a resource determined based a correspondence between a resource for the data and a resource for feedback.