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A method of conducting Push-To-Talk (PTT) group call in a packet based network without dispatch server

IP.com Disclosure Number: IPCOM000242460D
Original Publication Date: 2015-Jul-16
Included in the Prior Art Database: 2015-Jul-16
Document File: 5 page(s) / 55K

Publishing Venue

Motorola

Related People

Gong, Ya.Hui.: INVENTOR [+6]

Abstract

A method to conduct Push-To-Talk (PTT) group call in a packet based network without adding additional dispatch server is introduced here. An algorithm to calculate unique multicast address for the PTT group call is introduced with two procedures to detect and solve the potential access conflicts for both outside and inside of a group call. The procedure to detect and resolve the potential access conflict for outside of a group call is to avoid conflict with other multicast services. The procedure to detect and resolve the potential access conflict for inside of a group call is to avoid multiple users talk problem. The later communication of the PTT group call is conducted by using multicast protocol.

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A method of conducting Push-To-Talk (PTT) group call in a packet based network without dispatch server

Gong YaHui, Tian Yong, Chen DaJun, Tang Yi, Liang ShiQiang, Wei Zhong

Motorola Solutions, Inc.

 

ABSTRACT

       A method to conduct Push-To-Talk (PTT) group call in a packet based network without adding additional dispatch server is introduced here. An algorithm to calculate unique IP multicast address for the PTT group call is introduced with two procedures to detect and solve the potential access conflicts for both outside and inside of a group call. The procedure to detect and resolve the potential access conflict for outside of a group call is to avoid conflict with other multicast services. The procedure to detect and resolve the potential access conflict for inside of a group call is to avoid multiple users talk problem. The later communication of the PTT group call is conducted by using multicast protocol.

PROBLEM

       Group call is a major functionality of two way radio systems. To implement this functionality in packet based network normally requires additional dispatch server to dispatch group calls to group members and arbitrate access conflicts.

This disclosure introduces a simple and effective way to conduct PTT group call without a dispatch server or when the existing dispatch server is down.

SOLUTION

The method introduced by this paper comprises of an algorithm to dynamically generate a unique multi cast IP address for a talk group, a procedure to detect and solve potential access conflicts with other multicast services in the same network, a procedure to detect and solve potential access conflict from the same group members, a procedure to detect and solve transmitting audio conflict within same talk group.

      

       A new multicast IP address is re-generated according to the address conflict resolution rule, if the multicast IP address generated dynamically is employed by another multicast service.

      Vote window and Vote Window Reminder are used to solve potential PTT access conflict from other member(s) in the same group.

Figure – 1 illustrates the work flow of this solution.

              Figure – 1 Solution work flow

OPERATION

1.    Overview

Figure-2 shows radio 1 initiating group call after generating multicast IP address and resolving potential conflict with other multicast services, other three radios receive group call in packet based network without dispatch server. These four radios, belong to the same talk group, can generate the same multicast IP address and join the same multicast group 206. Group call voice is IP multicast to all members of the 206 group.

Figure – 2 Group Call in packet based network

2.    Generate unique multicast IP address

Figure – 3 shows an algorithm for converting Talk Group ID to unique multicast IP address which includes multicast IP address confliction resolution between different multicast services. This algorithm is executed when th...