# US 2021/0345447 A1 · 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 2021/0345447 A1 - Document ID: US20210345447A1 - Status: Published application - Kind: A1 - Application number: 16/317,466 - Filed: 2017-07-14 - Published: 2021-11-04 - 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/US20210345447A1 ## 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 for managing a first-to-answer call by a mission critical push to talk (MCPTT) server in a wireless communication system, the method comprising: receiving, from a MCPTT originating client, a first-to-answer call request; transmitting, to a plurality of MCPTT recipient clients, the first-to-answer call request; receiving, from a first MCPTT recipient client among the plurality of MCPTT recipient clients, a first-to-answer call response; and transmitting, to the MCPTT originating client, the first-to-answer call response for the MCPTT originating client to establish a media plane with the first MCPTT recipient client. ### Claim 2 (depends on 1) The method of claim 1, wherein the first-to-answer call request comprises at least one of a group identifier, the plurality of MCPTT recipient clients, a resource list, a uniform resource identifier (URI), and a group URI. ### Claim 3 (depends on 1) The method of claim 1, further comprising: identifying that MCPTT users of the plurality of MCPTT recipient clients are authorized for the first-to-answer call. ### Claim 4 (depends on 1) The method of claim 1, further comprising: determining a list of MCPTT users to transmit the first-to-answer call request based on information obtained from the first-to-answer call request. ### Claim 5 (depends on 1) The method of claim 1, further comprising: receiving, from a second MCPTT recipient client among the plurality of MCPTT recipient clients, a first-to-answer call response; transmitting, to the second MCPTT recipient client, a first-to-answer call cancel request, if the first-to-answer call response from the first MCPTT recipient client is already accepted; and receiving, from the second MCPTT recipient client, a first-to-answer call cancel response. ### Claim 6 A method for managing a first-to-answer call by a mission critical push to talk (MCPTT) originating client in a wireless communication system, the method comprising: transmitting, to a MCPTT server, a first-to-answer call request; receiving, from the MCPTT server, a first-to-answer call response corresponding to the first-to-answer call request, wherein the first-to-answer call response is for a first MCPTT recipient client among a plurality of MCPTT recipient clients; and establishing a media plane with the first MCPTT recipient client through the MCPTT server. ### Claim 7 (depends on 6) The method of claim 6, wherein the first-to-answer call request comprises at least one of a group identifier, the plurality of MCPTT recipient clients, a resource list, a uniform resource identifier (URI), and a group URI. ### Claim 8 A method for managing a first-to-answer call by a mission critical push to talk (MCPTT) recipient client in a wireless communication system, the method comprising: receiving, from a MCPTT server, a first-to-answer call request of a MCPTT originating client; and transmitting, to the MCPTT server, a first-to-answer call response corresponding to the first-to-answer call request, for the MCPTT originating client to establish a media plane with the MCPTT recipient client. ### Claim 9 (depends on 8) The method of claim 8, wherein the first-to-answer call request comprises at least one of a group identifier, the plurality of MCPTT recipient clients, a resource list, a uniform resource identifier (URI), and a group URI. ### Claim 10 A mission critical push to talk (MCPTT) server for managing a first-to-answer call in a wireless communication system, the MCPTT server comprising: a transceiver; and a controller, coupled to the transceiver, configured to receive, from a MCPTT originating client, a first-to-answer call request, transmit, to a plurality of MCPTT recipient clients, the first-to-answer call request, receive, from a first MCPTT recipient client among the plurality of MCPTT recipient clients, a first-to-answer call response, and transmit, to the MCPTT originating client, the first-to-answer call response for the MCPTT originating client to establish a media plane with the first MCPTT recipient client. ### Claim 11 (depends on 10) The MCPTT server of claim 10, wherein the first-to-answer call request comprises at least one of a group identifier, the plurality of MCPTT recipient clients, a resource list, a uniform resource identifier (URI), and a group URI. ### Claim 12 (depends on 10) The MCPTT server of claim 10, wherein the controller is configured to: identify that MCPTT users of the plurality of MCPTT recipient clients are authorized for the first-to-answer call; and determine a list of the MCPTT users to transmit the first-to-answer call request based on information obtained from the first-to-answer call request. ### Claim 13 (depends on 10) The MCPTT server of claim 10, wherein the controller is configured to: receive, from a second MCPTT recipient client among the plurality of MCPTT recipient clients, a first-to-answer call response, transmit, to the second MCPTT recipient client, a first-to-answer call cancel request, if the first-to-answer call response from the first MCPTT recipient client is already accepted, and receive, from the second MCPTT recipient client, a first-to-answer call cancel response. ### Claim 14 A mission critical push to talk (MCPTT) originating client for managing a first-to-answer call in a wireless communication system, the MCPTT originating client comprising: a transceiver; and a controller, coupled to the transceiver, configured to transmit, to a MCPTT server, a first-to-answer call request, receive, from the MCPTT server, a first-to-answer call response corresponding to the first-to-answer call request, wherein the first-to-answer call response is for a first MCPTT recipient client among a plurality of MCPTT recipient clients, and establish a media plane with the first MCPTT recipient client through the MCPTT server. ### Claim 15 A mission critical push to talk (MCPTT) recipient client for managing a first-to-answer call in a wireless communication system, the MCPTT recipient client comprising: a transceiver; and a controller, coupled to the transceiver, configured to receive, from a MCPTT server, a first-to-answer call request of a MCPTT originating client, and transmit, to the MCPTT server, a first-to-answer call response corresponding to the first-to-answer call request, for the MCPTT originating client to establish a media plane with the MCPTT recipient client.