# US 2021/0281981 A1 · Communications Method, Apparatus and System > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0281981 A1 - Document ID: US20210281981A1 - Status: Published application - Kind: A1 - Application number: 17/331,303 - Filed: 2021-05-26 - Published: 2021-09-09 - Earliest claimed: 2018-11-27 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Meng Li; Yanmei Yang - Web page: https://patentgrep.com/patent/US20210281981A1 ## CPC - H04W 4/06: Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services - H04L 12/1836: {with heterogeneous network architecture} - H04L 12/189: {in combination with wireless systems (selective distribution or broadcast in wireless communication networks H04W4/06)} - H04L 65/1069: Session establishment or de-establishment - H04L 65/611: for multicast or broadcast (systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06) - H04N 21/6131: {involving transmission via a mobile phone network (wireless downlink channel access H04W74/006)} - H04N 21/6405: Multicasting {(data broadcast and multicast in packet switching networks H04L12/18)} - H04W 4/02: Services making use of location information - H04W 76/11: Allocation or use of connection identifiers - H04W 76/15: Setup of multiple wireless link connections - H04W 76/40: for selective distribution or broadcast - H04W 16/18: Network planning tools - H04W 88/18: Service support devices; Network management devices - 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) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Embodiments of this application disclose a communications method, apparatus, and system. Specifically, after receiving information about a multicast area from a sender of a multicast service, a first core network device in a first network obtains, based on the information, indication information indicates that the first network cannot support the multicast service in the multicast area, or indicates that the first network supports the multicast service in a portion of areas of the multicast area; and sends the indication information to the sender. In this way, the sender of the multicast service can determine whether the first network supports the multicast service in the multicast area. ## Claims ### Claim 1 A communication method, comprising: sending, by a sender of a multicast service, information about a multicast area to a first core network device, wherein the first core network device belongs to a first network; and receiving, by the first core network device, the information about the multicast area; obtaining, by the first core network device based on the information about the multicast area, indication information, wherein the indication information is used to indicate that the first network cannot support the multicast service in the multicast area, or is used to indicate that the first network supports the multicast service in a portion of areas of the multicast area; sending, by the first core network device, the indication information to the sender; and receiving, by the sender, the indication information. ### Claim 2 (depends on 1) The communication method according to claim 1, wherein the information about the multicast area is carried in a first message, and the first message is used to request to establish a first multicast session in the multicast area. ### Claim 3 (depends on 2) The communication method according to claim 2, wherein the indication information is used to indicate that the first network supports the multicast service in the portion of areas of the multicast area; and the indication information comprises information about a first area, wherein the first area is an area in which the first network supports the multicast service in the multicast area; or the indication information comprises information about a second area, and the second area is an area in which the first network does not support the multicast service in the multicast area. ### Claim 4 (depends on 3) The communication method according to claim 3, wherein the indication information further comprises information about a second multicast session, the second multicast session is a multicast session established in the first area, and the second multicast session belongs to the first network. ### Claim 5 (depends on 2) The communication method according to claim 2, wherein the indication information is used to indicate that the first network supports the multicast service in the portion of areas of the multicast area; and the indication information comprises information about a first area and information about a third area, wherein the first area is an area in which the first network supports the multicast service in the multicast area, and the third area is an area in which a second network supports the multicast service in the multicast area. ### Claim 6 (depends on 2) The communication method according to claim 2, wherein the indication information comprises information about a third multicast session, the third multicast session is a multicast session established in the multicast area, and the third multicast session belongs to a second network. ### Claim 7 (depends on 2) The communication method according to claim 2, wherein the indication information is used to indicate that the first network supports the multicast service in the portion of areas of the multicast area; and the indication information comprises information about a second multicast session and information about a fourth multicast session, wherein the second multicast session is a multicast session established in a first area, and the second multicast session belongs to the first network; the fourth multicast session is a multicast session established in a second area, and the fourth multicast session belongs to a second network; the first area is an area in which the first network supports the multicast service in the multicast area; and the second area is an area in which the first network does not support the multicast service in the multicast area. ### Claim 8 (depends on 1) The communication method according to claim 1, wherein when the indication information is used to indicate that the first network cannot support the multicast service in the multicast area, the communication method further comprises: initiating, by the sender, establishment of a unicast session of the first network in the multicast area; or initiating, by the sender, establishment of a multicast session of a second network in the multicast area. ### Claim 9 (depends on 1) The communication method according to claim 1, wherein when the indication information is used to indicate that the first network supports the multicast service in the portion of areas of the multicast area, the indication information comprises information about a first area or comprises information about a second area, wherein the first area is an area in which the first network supports the multicast service in the multicast area, and the second area is an area in which the first network does not support the multicast service in the multicast area; and the communication method further comprises: initiating, by the sender, establishment of a unicast session of the first network in the multicast area; or initiating, by the sender, establishment of a multicast session of a second network in the multicast area; or initiating, by the sender, establishment of a multicast session of the first network in the first area and establishment of a unicast session of the first network in the second area; or initiating, by the sender, establishment of a multicast session of the first network in the first area. ### Claim 10 (depends on 1) The communication method according to claim 1, wherein when the indication information is used to indicate that the first network supports the multicast service in the portion of areas of the multicast area, the indication information comprises information about a first area and information about a third area, wherein the first area is an area in which the first network supports the multicast service in the multicast area, and the third area is an area in which a second network supports the multicast service in the multicast area; and the communication method further comprises: initiating, by the sender, establishment of a multicast session of the first network in the first area; or initiating, by the sender, establishment of a multicast session of the second network in the third area; or initiating, by the sender, establishment of a unicast session of the first network in the multicast area; or initiating, by the sender, establishment of a unicast session of the second network in the multicast area. ### Claim 11 A communication system, comprising: a sender of a multicast service and a first core network device, wherein the sender, configured to send information about a multicast area to the first core network device, wherein the first core network device belongs to a first network; and the first core network device, configured to receive the information about the multicast area, and obtain, based on the information about the multicast area, indication information, wherein the indication information is used to indicate that the first network cannot support the multicast service in the multicast area, or is used to indicate that the first network supports the multicast service in a portion of areas of the multicast area; and send the indication information to the sender; and the sender, further configured to receive the indication information. ### Claim 12 (depends on 11) The communication system according to claim 11, wherein the information about the multicast area is carried in a first message, and the first message is used to request to establish a first multicast session in the multicast area. ### Claim 13 (depends on 12) The communication system according to claim 12, wherein the indication information is used to indicate that the first network supports the multicast service in the portion of areas of the multicast area; and the indication information comprises information about a first area, wherein the first area is an area in which the first network supports the multicast service in the multicast area; or the indication information comprises information about a second area, and the second area is an area in which the first network does not support the multicast service in the multicast area. ### Claim 14 (depends on 13) The communication system according to claim 13, wherein the indication information further comprises information about a second multicast session, the second multicast session is a multicast session established in the first area, and the second multicast session belongs to the first network. ### Claim 15 (depends on 12) The communication system according to claim 12, wherein the indication information is used to indicate that the first network supports the multicast service in the portion of areas of the multicast area; and the indication information comprises information about a first area and information about a third area, wherein the first area is an area in which the first network supports the multicast service in the multicast area, and the third area is an area in which a second network supports the multicast service in the multicast area. ### Claim 16 (depends on 12) The communication system according to claim 12, wherein the indication information comprises information about a third multicast session, the third multicast session is a multicast session established in the multicast area, and the third multicast session belongs to a second network. ### Claim 17 (depends on 12) The communication system according to claim 12, wherein the indication information is used to indicate that the first network supports the multicast service in the portion of areas of the multicast area; and the indication information comprises information about a second multicast session and information about a fourth multicast session, wherein the second multicast session is a multicast session established in a first area, and the second multicast session belongs to the first network; the fourth multicast session is a multicast session established in a second area, and the fourth multicast session belongs to a second network; the first area is an area in which the first network supports the multicast service in the multicast area; and the second area is an area in which the first network does not support the multicast service in the multicast area. ### Claim 18 (depends on 11) The communication system according to claim 11, wherein when the indication information is used to indicate that the first network cannot support the multicast service in the multicast area, the sender is further configured to: initiate establishment of a unicast session of the first network in the multicast area; or initiate establishment of a multicast session of a second network in the multicast area. ### Claim 19 (depends on 11) The communication system according to claim 11, wherein when the indication information is used to indicate that the first network supports the multicast service in the portion of areas of the multicast area, the indication information comprises information about a first area or comprises information about a second area, wherein the first area is an area in which the first network supports the multicast service in the multicast area, and the second area is an area in which the first network does not support the multicast service in the multicast area; and the sender is further configured to: initiate establishment of a unicast session of the first network in the multicast area; or initiate establishment of a multicast session of a second network in the multicast area; or initiate establishment of a multicast session of the first network in the first area and establishment of a unicast session of the first network in the second area; or initiate establishment of a multicast session of the first network in the first area. ### Claim 20 (depends on 11) The communication system according to claim 11, wherein when the indication information is used to indicate that the first network supports the multicast service in the portion of areas of the multicast area, the indication information comprises information about a first area and information about a third area, wherein the first area is an area in which the first network supports the multicast service in the multicast area, and the third area is an area in which a second network supports the multicast service in the multicast area; and the sender is further configured to: initiate establishment of a multicast session of the first network in the first area; or initiate establishment of a multicast session of the second network in the third area; or initiate establishment of a unicast session of the first network in the multicast area; or initiate establishment of a unicast session of the second network in the multicast area.