Möller, Sebastian; Wältermann, Marcel; Lewcio, Blazej; Kirschnick, Niklas; Vidales, Pablo (Deutsche Telekom Laboratories, TU Berlin, Ernst-Reuter-Platz 7, 10587 Berlin)
Next Generation Networks provide seamless access to speech and multimedia transmission services at different bandwidths. Depending on the audio bandwidth of the speech codecs used in the respective networks, as well as on network degradations resulting from the handover, coding, and packet loss, the quality experienced by the user will differ within a single call. In this paper, we present initial results from a series of subjective listening-only and conversational experiments in which speech quality is quantified as a function of handover, codec change, and network characteristics. The results show when and under which circumstances a handover should be scheduled in order to obtain best speech quality. They are important for the development of high-quality handover strategies.