| Faced with the impact and challenges brought by Internet OTT applications,operators have proposed the concept of 5G new calling,which provides richer and more reliable real-time interactive communication services.However,the existing implementation in the IMS network only supports two channels,audio and video,to support multimedia services,and there is limited optimization space under the existing architecture.In order to improve the overly single original mobile calling function,this thesis introduces a data channel to be superimposed on the existing audio and video channels,and fully utilizes the computing power of terminals.This method can not only maintain the security of calls,but also provide more stable and higher-quality real-time communication services than OTT.In addition,this method can transform basic voice and video communication into an interactive communication experience,thus solving the problems of real-time business and high computing power consumption.This thesis designs and implements an IMS data channel server,introduces a brand-new data channel and superimposes it with audio and video channels,and supports new calling-related businesses.According to the characteristics of the new calling business scenario,this thesis proposes a new congestion control mechanism that comprehensively considers bandwidth and priority.By combining bandwidth estimation-based congestion control with flow priority management,the aim is to provide fair bandwidth allocation and reduce congestion.The bandwidth changes are monitored in real-time during the SCTP congestion control process,so as to accurately adjust the parameters of congestion control and improve the performance of congestion control.In the case of multiple data channels superimposed,different priorities are assigned to data channels of different business types,and different rate priorities are implemented to reduce overall latency and packet loss and improve fairness.Through comparative experiments and data analysis in simulated IMS networks,the feasibility of the IMS data channel server and the effectiveness of the proposed algorithm are verified.The experimental results show that the bandwidth-based congestion control and flow priority management increase the average utilization of the bandwidth by 23.5%and improve the overall average QoS of the server by 44.7%. |
