Dual stream transmission to improve mobile VoIP services over HSPA: A practical test bed

As we already know, perceived speech quality of mobile VoIP applications depends on the individual telephone operator where the radio link is not always reliable for the entire duration of a conversation. Moreover, the quality of voice traffic over IP is greatly reduced due to the strong current limitations in terms of requirements regarding delay and guaranteed bandwidth. In particular, the scope of the paper is to present the architecture and the performance evaluation of a dual stream approach to mobile VoIP applications. Test results, obtained via practical test bed, in which a duplicate copy of a voice packet is sent using two different HSPA operators, present an average packet loss reduction of 60% and an average improvement of speech quality of about 0,8 MOS.