Method and system for circuit switched fallback, server and mobile terminal

Abstract

The invention provides a method for circuit switched fallback, a CSCF (Call Session Control Function) server, a mobile terminal, a mobility management entity and a system for circuit switched fallback. The method comprises the following steps of receiving protocol signaling for initiating VoLTE (Voice over LTE) voice service from the mobile terminal; determining whether to send a service query command to the mobility management entity of the mobile terminal according to the protocol signaling; and receiving a query result from the mobility management entity and sending a circuit switched fallback command to the mobile terminal according to the query result in order to make the mobile terminal execute a circuit switched fallback operation. Through the technical scheme of the invention, the mobile terminal can be effectively guided to execute the circuit switched fallback operation to guarantee continuity of a voice call, so that the voice call quality of the mobile terminal supporting IMS (IP Multimedia Subsystem) service is effectively improved, the user experience is promoted, and meanwhile, an LTE (Long Term Evolution) network can select the voice communication mode of the mobile terminal according to the current network state.

Description

technical field [0001] The present invention relates to the technical field of terminals, in particular to a voice call fallback method, a CSCF server, a mobile terminal, a mobility management entity and a voice call fallback system. Background technique [0002] In the case that the current LTE (Long Term Evolution, Long Term Evolution) network coverage is incomplete and the IMS (IP Multimedia Subsystem, IP (Internet Protocol, Internet Protocol, interconnection protocol) multimedia system) service has not been fully developed, in order to ensure the voice service of mobile terminals Reliability, the LTE network provides CSFB (CircuitSwitchedFallback, voice call fallback) and SRVCC (SingleRadioVoiceCallContinuity, dual-mode single-standby wireless voice call continuity) two technologies. [0003] In the related technology, when the mobile terminal or the LTE network cannot support the IMS service, the mobile terminal falls back to 2G from the LTE network through the Voice Ca...

AI Technical Summary

Problems solved by technology

[0004] However, whether to choose CSFB mode or SRVCC mode needs to be configured on the mobile terminal side, which is not conducive to the deployment of IMS services: if the mobile terminal configuration does not support IMS services, the mobile terminal must Initiate CSFB through the OTA (OverTheAir, "Over The Air" technology used by mobile terminals such as mobile phones) signaling on the LTE network. Then, with the gradual maturity of IMS service deployment on the network side, it will take a lot of time and effort to upgrade mobile terminals to support IMS services. At the same time, it also affects the migration of the original 2G / 3G network to the LTE network; if the mobile terminal supports IMS services, the mobile terminal and the LTE network will not initiate CSFB, but use VoLTE (VoiceOverLTE, IMS-based voice service) and SRVCC technology If you want to make voice calls, then, in areas where the deployment of LTE network and IMS services is not yet mature, there will be a large number of call failures and dropped calls, and the quality of voice calls cannot be guaranteed

Images