# US 11,310,290 B2 · System and method for establishing first-to-answer call in mission critical push to talk communication > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,310,290 B2 - Document ID: US11310290B2 - Status: Granted - Kind: B2 - Application number: 16/317,466 - Filed: 2017-07-14 - Published: 2021-11-04 - Granted: 2022-04-19 - Earliest claimed: 2016-07-15 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd - Inventors: Basavaraj Jayawant Pattan; Suresh Chitturi; Nishant Gupta - Web page: https://patentgrep.com/patent/US11310290B2 ## CPC - H04L 65/1069: Session establishment or de-establishment - H04L 65/4061: Push-to services, e.g. push-to-talk or push-to-video - H04W 4/10: Push-to-Talk [PTT] or Push-On-Call services - H04W 12/06: Authentication - H04W 12/08: Access security - H04W 76/10: Connection setup - H04W 76/45: for Push-to-Talk [PTT] or Push-to-Talk over cellular [PoC] services - 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 The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. Embodiments herein provide a system for establishing a first-to-answer call in a Mission Critical Push to Talk (MCPTT) communication. The system includes a MCPTT originating client configured to initiate a first-to-answer call and transmit a first-to-answer call request to a MCPTT server. The system includes the MCPTT server configured to receive the first-to-answer call request from the MCPTT client. ## Claims ### Claim 1 A method performed by a mission critical push to talk (MCPTT) server in a communication system, the method comprising: receiving, from an MCPTT originating client, a first MCPTT first-to-answer call request message; identifying at least one MCPTT user to transmit a second MCPTT first-to-answer call request message based on the first MCPTT first-to-answer call request message; transmitting, to at least one MCPTT recipient client of the at least one MCPTT user, the second MCPTT first-to-answer call request message; receiving, from a first MCPTT recipient client among the at least one MCPTT recipient client, a first MCPTT first-to-answer call response message; and transmitting, to a second MCPTT recipient client among the at least one MCPTT recipient client, an MCPTT first-to-answer call request message. ### Claim 2 (depends on 1) The method of claim 1, wherein the first MCPTT first-to-answer call request message includes at least one of an MCPTT identifier associated with the at least one the plurality of MCPTT recipient client associated with the at least one MCPTT receipt client. ### Claim 3 (depends on 2) The method of claim 2, wherein the first MCPTT first-to-answer call request message further includes a session description protocol (SDP) offer including at least one media parameter. ### Claim 4 (depends on 1) The method of claim 1, further comprising: transmitting, to the MCPTT originating client, a second MCPTT first-to-answer call response message indicating that an MCPTT user of the first MCPTT recipient client has accepted a call. ### Claim 5 (depends on 4) The method of claim 4, wherein the second MCPTT first-to-answer call response message includes a session description protocol (SDP) answer including a media parameter selected from at least one media parameter, and wherein the at least one media parameter is included in the first MCPTT first-to-answer call request message. ### Claim 6 A mission critical push to talk (MCPTT) server comprising: a communication unit; and a controller coupled with the communication unit and configured to: receive, from an MCPTT originating client, a first MCPTT first-to-answer call request message, identify at least one MCPTT user to transmit a second MCPTT first-to-answer call request message based on the first MCPTT first-to-answer call request message, transmit, to at least one MCPTT recipient client of the at least one MCPTT user, the second MCPTT first-to-answer call request message, receive, from a first MCPTT recipient client among the at least one MCPTT recipient client, a first MCPTT first-to-answer call response message, and transmit, to a second MCPTT recipient client among the at least one MCPTT recipient client, an MCPTT first-to-answer call cancel request message. ### Claim 7 (depends on 6) The MCPTT server of claim 6, wherein the first MCPTT first-to-answer call request message includes at least one of an MCPTT identifier associated with the MCPTT originating client, or an MCPTT identifier associated with the at least one MCPTT recipient client. ### Claim 8 (depends on 7) The MCPTT server of claim 7, wherein the first MCPTT first-to-answer call request message further includes a session description protocol (SDP) offer including at least one media parameter. ### Claim 9 (depends on 6) The MCPTT server of claim 6, wherein the controller is configured to transmit, to the MCPTT originating client, a second MCPTT first-to-answer call response message indicating that an MCPTT user of the first MCPTT recipient client has accepted a call. ### Claim 10 (depends on 9) The MCPTT server of claim 9, wherein the second MCPTT first-to-answer call response message includes a session description protocol (SDP) answer including a media parameter selected from at least one media parameter, and wherein the at least one media parameter is included in the first MCPTT first-to-answer call request message. ### Claim 11 A method performed by a terminal for a mission critical push to talk (MCPTT) service in a communication system, the method comprising: receiving, from an MCPTT server, an MCPTT first-to-answer call request message of an MCPTT originating client; transmitting, to the MCPTT server, an MCPTT first-to-answer call response message in response to the MCPTT first-to-answer call request message; and receiving, from the MCPTT server, an MCPTT first-to-answer call cancel request message. ### Claim 12 (depends on 11) The method of claim 11, further comprising: transmitting, to the MCPTT server, an MCPTT first-to-answer call cancel response message. ### Claim 13 (depends on 11) The method of claim 11, wherein the MCPTT first-to-answer call request message includes a session description protocol (SDP) offer including at least one media parameter. ### Claim 14 (depends on 11) The method of claim 11, wherein the MCPTT first-to-answer call response message indicates that an MCPTT user of the terminal has accepted a call. ### Claim 15 (depends on 14) The method of claim 14, wherein the MCPTT first-to-answer call response message includes a session description protocol (SDP) answer including a media parameter selected from at least one media parameter, and wherein the at least one media parameter is included in the MCPTT first-to-answer call request message. ### Claim 16 A terminal for a mission critical push to talk (MCPTT) service in a communication system, the terminal comprising: a transceiver; and a controller coupled with the transceiver and configured to: receive, from an MCPTT server, an MCPTT first-to-answer call request message of an MCPTT originating client, transmit, to the MCPTT server, an MCPTT first-to-answer call response message in response to the MCPTT first-to-answer call request message, and receive, from the MCPTT server, an MCPTT first-to-answer call cancel request message. ### Claim 17 (depends on 16) The terminal of claim 16, wherein the controller is further configured to transmit, to the MCPTT server, an MCPTT first-to-answer call cancel response message. ### Claim 18 (depends on 16) The terminal of claim 16, wherein the MCPTT first-to-answer call request message includes a session description protocol (SDP) offer including at least one media parameter. ### Claim 19 (depends on 16) The terminal of claim 16, wherein the MCPTT first-to-answer call response message indicates that an MCPTT user of the terminal has accepted a call. ### Claim 20 (depends on 19) The terminal of claim 19, wherein the MCPTT first-to-answer call response message includes a session description protocol (SDP) answer including a media parameter selected from at least one media parameter, and wherein the at least one media parameter is included in the MCPTT first-to-answer call request message.