China Telecom VoLTE Network Testing And Optimization In Shanghai Area

VoLTE is the solution for voice over LTE network which utilizes EPC as access network and IMS as service control network.VoLTE technology can provide better service perceived experience,and improve frequency efficiency of wirless resource simultaneously.This thesis presents a comprehensive research on VoLTE network testing and optimization network,based on China Telecom in Shanghai area.Firstly,this thesis gives a brief introduction of principles and key technologies of VoLTE including main composition of IMS,IMS signaling process,and EVS coding,etc.Then,the detailed VoLTE network implementation scheme is analyzed such as network element configuration,anchoring scenario,voice routing,domain selection,MRPF,respectively.Based on China Telecom overall planning and Shanghai area current situation,this thesis presents a indepth research on VoLTE testing and optimization strategy,along with the proposed solution for SBC disaster tolerance and similar different failure response measures.The proposed solution has been verified in actual network project which will provide good support for VoLTE commercial deployment in China Telecom.Cosidering the calling anchoring scheme is not perfect which met some problems after the testing network deployment,this thesis presents various solutions.For example,the format of the calling number sent by MGCF of Shanghai Alcatel-Bell is inconsistent with the number format of the contract signed in Huawei HSS,which leads the user number cannot be found when querying the HSS.Aiming at this kind of inter-vendor adaptation problem,this thesis adopts adding an ADG calling distribution network element in the routing process.The routing scheme is optimized by referring to the existing CDMA intelligent network user routing strategy in Shanghai.The optimized solution can be distributed through ADG network elements which can distinguish CDMA intelligent network users from VoLTE users.Furthermore,it can also deploy the number regularization function to unify the calling number format for successfully querying the HSS.This thesis also proposed optimizaztion issue for current P-CSCF disaster recovery program.The existing disaster recovery scheme will take up to 50 minutes to restore services when a P-CSCF fails and the terminal needs to wait for the re-registration process.The optimization shceme will provide the user service recovery time shortened to a maximum of two times when a P-CSCF fails.Thus the reliability of the existing network can be improved obviously.The proposed optimized scheme for the VoLTE in Shanghai has effectively improved the network quality and user perception through service testing and actual operation,which rovides strong support for China Telecom's large-scale VoLTE commercial deployment.