The Estimation of the Best R Factor of the Path and the Application in the Multipath Transmission

In the VOIP system, the researches on using the multipath transmission method to enhance speech quality of the system have been seen in reports. But there is no much report on how to estimate the link and how to choose the optimal path. In this paper, according to the mentioned problem, the research on the E-model (the model for predicting voice quality) of the ITU-T is carried out. The relationship among the R factor, the delay and packet-loss rate is derived from the simulating curves and formulas. A method and the steps of realization of estimating the best R factor of each path based on the characteristics of the link delay and the E-model are proposed. Firstly, we can get the network delay sequence T_N by the RTP; Secondly, the statistical characteristics of the link are obtained by means of the maximum likelihood law and it is estimated. Lastly, the best path is chosen by the RTCP and the best buffer delay is set up to get the best quality of speech on each single path.