Voice Packet Loss Concealment Algorithm Based On VOIP

In China,The development of internet technology is changing everyday,at the same time,the application which is based on internet technology has been constan-tly launched.Along with the advance of digital voice signal processing technolo-gy,the application that using the IP to transmit real-time voice information and finish the voice calls has also been launched constantly.This application has very obvious advantage compared with the traditional telephone voice so that it is wide-ly used.The voice messages need to be grouped and packaged while they are transm-ited in the IP network.But,it often appears jitter,packet loss and delay as the unstable transmission characteristics of the IP network which will lead to the voice data will not be able to accurately reach the receiver,then the call quality will be influenced.The real time requirement for the voice information is very high in the proess of phone call,so we can not ask the sender to send it again when some voice packets loss.Then,we need to take the corresponding technology of voice information repair to make up for the voice lost which comes from the packet loss.For the existing packet loss repair methods,the packet loss recovery technique which is mainly used at the sender is better than the packet loss concealment technique which is used at the receiver.But the packet loss recovery technique is relatively too complicated,and it will introduce more bandwidth and delay to network. In the case of high packet loss rate the packet loss concealment also can get better voice quality when using the better packet loss concealment algorithm. WSOLA algorithm which is based on the temporal scale is a kind of packet loss concealment method that can get the better repair effect.But the standard WSOLA algotithm required a lot of calculation when calculating the cross correlation coefficient,it will introduce too much calculation delay and affect the quality of repair voice.According to the above problem,this paper expounds the principle of VoIP in detail; introducing the digital voice and network transmission technology which are related to the VoIP network;analysing the relevant methods which are used to solve the problem of VoIP packet loss;the temporal scale which belongs to the packet loss concealment methods is mainiy studied;Further studing the WSOLA algorithm’s principle and putting forward an improved cross correlation coefficient calculation method.Finally,this paper through the software simulation experiment to analysis the WSOLA algorithm and the improved algorithm,also the experiment is used to determine the speech repair effecf of them.The experiment result shows that the improved algorithm requires less compulation,at the same time the improved algorithm can better guarantee the repair voice quality.