Softswitch Network Ip Transmission Quality Assessment Methods

With the issuance of 3G licenses in China,the quantity of softswitch nodes in network has been increasing rapidly,and softswitch technology has also been widely used by major operators.Meanwhile,the benefits of IP bearer in mobile network are more and more widely recognized,which make the IP transformation of mobile network become inevitable.On the other hand,IP bearer also brings new problems for mobile network due to its weakness in QoS control.This thesis described the IP transmission quality impact on softswitch core network,especially on the negative effects of IP delay, jitter,and package loss.The main methods of improving IP transmission quality in mobile networks were introduced,including bandwidth saving, data buffering,package loss processing and admission controlling.Since operator relies on KPI to evaluate the performance of network,after IP transformation of mobile core network,IP related KPI system must be reconstructed,and its evaluation method must be rebuilt.The protocols of IP signaling and IP voice were analyzed,and some suggestions on KPI establishment were given.Statistic sources,as well as calculation methods for both MSC server and MGW were given discussed.Finally,an evaluation method based on end-user perception for IP transmission quality in softswitch network was proposed,A simplified softswitch network in test plant was designed to measure the actual impact of IP delay,jitter and package loss.IP disturbances were added intentionally,and test calls were made.The experimental data obtained in the test could be used for reference as IP disturbance indicator.The method based on end-user perception could also be helpful when complete KPI system is established in the future.