# US 2021/0242974 A1 · Radio communication method and apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0242974 A1 - Document ID: US20210242974A1 - Status: Published application - Kind: A1 - Application number: 17/237,148 - Filed: 2021-04-22 - Published: 2021-08-05 - Earliest claimed: 2018-10-30 - Assignees: KYOCERA Corporation - Applicants: KYOCERA Corporation - Inventors: Masato FUJISHIRO - Web page: https://patentgrep.com/patent/US20210242974A1 ## CPC - 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 80/02: Data link layer protocols - 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 radio communication method is used in a mobile communication system, the method includes: generating, by a PDCP entity corresponding to a PDCP layer, a packet; transmitting, by a first transmission entity, the packet; and based on unsuccessful transmission of the packet by the first transmission entity, performing duplicate transmission of the packet, including: retransmitting, by the first transmission entity, the packet and transmitting, by a second transmission entity different from the first transmission entity, the packet. Each of the first transmission entity and the second transmission entity corresponds to a layer lower than the PDCP layer. ## Claims ### Claim 1 A radio communication method used in a mobile communication system, the method comprising: generating, by a PDCP entity corresponding to a PDCP layer, a packet; transmitting, by a first transmission entity, the packet; and based on unsuccessful transmission of the packet by the first transmission entity, performing duplicate transmission of the packet, including: retransmitting, by the first transmission entity, the packet, and transmitting, by a second transmission entity different from the first transmission entity, the packet; wherein each of the first transmission entity and the second transmission entity corresponds to a layer lower than the PDCP layer. ### Claim 2 (depends on 1) The radio communication method according to claim 1, wherein the first transmission entity is configured to transmit the packet to a receiving side via a transmission path corresponding to a first carrier, and the second transmission entity is configured to transmit the packet to the receiving side via a transmission path corresponding to a second carrier different from the first carrier. ### Claim 3 (depends on 1) The radio communication method according to claim 1, wherein the layer lower than the PDCP layer that corresponds to each of the first transmission entity and the second transmission entity is an RLC layer. ### Claim 4 (depends on 1) The radio communication method according to claim 1, further comprising: storing, by the PDCP entity, the generated packet; and providing, by the PDCP entity, the stored packet to the second transmission entity in response to the unsuccessful transmission of the packet by the first transmission entity, wherein in the performing duplicate transmission, the second transmission entity transmits the packet provided by the PDCP entity. ### Claim 5 (depends on 4) The radio communication method according to claim 4, further comprising: notifying, by the first transmission entity, the PDCP entity of NACK information including a sequence number of the packet which has been unsuccessfully transmitted. ### Claim 6 (depends on 1) The radio communication method according to claim 1, further comprising: providing, by the PDCP entity, the generated packet to both the first transmission entity and the second transmission entity; and storing, by the second transmission entity, the generated packet provided by the PDCP entity, wherein in the performing duplicate transmission, the second transmission entity is configured to transmit the stored packet in response to the unsuccessful transmission of the packet by the first transmission entity. ### Claim 7 (depends on 6) The radio communication method according to claim 6, further comprising: notifying, by the first transmission entity, the second transmission entity of NACK information including a sequence number of the packet that has been unsuccessfully transmitted. ### Claim 8 (depends on 6) The radio communication method according to claim 6, further comprising: notifying, by the first transmission entity, the second transmission entity of ACK information including a sequence number of the packet that has been successfully transmitted; and discarding, by the second transmission entity, the stored packet in response to the notification of the ACK information. ### Claim 9 (depends on 6) The radio communication method according to claim 6, further comprising: starting a timer when the second transmission entity stores the packet; and discarding, by the second transmission entity, the stored packet in response to expiration of the timer. ### Claim 10 (depends on 1) The radio communication method according to claim 1, further comprising: counting, by the first transmission entity, a number of unsuccessful transmissions of the packet, wherein the performing duplicate transmission is performed when the number reaches a predetermined number. ### Claim 11 (depends on 1) The radio communication method according to claim 1, further comprising: transmitting, by the second transmission entity, a next packet, when, in the performing duplicate transmission, the first transmission entity unsuccessfully retransmits the packet, and the second transmission entity successfully transmits the packet. ### Claim 12 (depends on 1) The radio communication method according to claim 1, wherein the PDCP entity and the first transmission entity and the second transmission entity are provided in one user apparatus. ### Claim 13 (depends on 1) The radio communication method according to claim 1, wherein the PDCP entity and the first transmission entity and the second transmission entity are provided in one base station. ### Claim 14 (depends on 1) The radio communication method according to claim 1, wherein the PDCP entity and the first transmission entity are provided in a first base station, and the second transmission entity is provided in a second base station different from the first base station. ### Claim 15 An apparatus used in a mobile communication system, the apparatus comprising: a PDCP entity corresponding to a PDCP layer and configured to generate a packet; a first transmission entity configured to transmit the packet; and a second transmission entity different from the first transmission entity, wherein wherein each of the first transmission entity and the second transmission entity corresponds to a layer lower than the PDCP layer, and based on unsuccessful transmission of the packet by the first transmission entity, the first transmission entity is configured to retransmit the packet, and the second transmission entity is configured to transmit the packet to perform duplicate transmission of the same packet by the first transmission entity and the second transmission entity.