PTT (Push-To-Talk) collision avoidance method for center-free commanding and dispatching communication system

Abstract

The invention discloses a PTT (Push-To-Talk) collision avoidance method for a center-free commanding and dispatching communication system based on the IP (Internet Protocol). The PTT collision avoidance method comprises the following steps: a user A presses a PTT key and requires a PTT talk; a timer Tr is started and the system broadcasts or multicasts a PTT request to a whole network; the system can delay to wait for a certain waiting interval Tw to monitor whether PTT requests of other users reach or not during the time period; and if no any request of the other users reaches in the waiting interval Tw, the A is accessed to a service channel to indicate that the user can speak. The invention provides a PTT arbitration method applied to the center-free commanding and dispatching communication system; with the adoption of the method, a PTT arbitration central node does not need to exist in the network and the PTT request can be sent by all terminal users in the system; and the whole network avoids PTT collision based on a certain rule and authorizes the certain user to carry out PTT talk. Meanwhile, a multi-priority service is realized.

Description

technical field [0001] The invention relates to a PTT collision avoidance method, in particular to a PTT collision avoidance method for an IP-based non-central command and dispatch communication system. Background technique [0002] In the command and dispatch system, PTT is a half-duplex service, that is, only the user who presses the PTT key can speak, and other users can only answer. Therefore, the PTT voice preemption function must be uniformly controlled to ensure that the system can Only one person is authorized for PTT push-to-talk. [0003] In the traditional command and dispatch system, the arbitration function of the PTT talk right is completed by a central network element in the network. For example, the arbitration of the PTT service in the digital trunking system may be completed by the MSC, and the arbitration of the PoC service in the IMS system is performed by the PoC Server Completed, that is, there must be a central node in the network, and the central poi...

AI Technical Summary

Problems solved by technology

[0004] It can be seen that the PTT talk right arbitration in the traditional system is completed by a certain central node, but for the non-central system, there is no central node in the network, and it is impossible to perform unified arbitration management, and it is impossible to aggregate the PTT of all users like the traditional system The request goes to the central node, and then the central node conducts unified arbitration, so it is necessary to find a PTT talk right arbitration method suitable for the non-central command and dispatch system

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