Testing the IQX Hypothesis for Exponential Interdependency between QoS and QoE of Voice Codecs iLBC and G.711

Document type: Conference Papers
Peer reviewed: Yes
Author(s): Tobias Hossfeld, David Hock, Phuoc Tran-Gia, Kurt Tutschku, Markus Fiedler
Title: Testing the IQX Hypothesis for Exponential Interdependency between QoS and QoE of Voice Codecs iLBC and G.711
Translated title: Testning av IQX hypotesen för exponentiell beroende mellan QoS och QoE i fall av röst-kodarna iLBC och G.711
Conference name: 18th ITC Specialist Seminar on Quality of Experience
Year: 2008
Pagination: 105-114
ISBN: ISSN 1103-1581
Publisher: BTH
City: Karlskrona
Organization: Blekinge Institute of Technology
Department: School of Engineering - Dept. of Telecommunication Systems (Sektionen för teknik – avd. för telekommunikationssystem)
School of Engineering S- 372 25 Ronneby
+46 455 38 50 00
Authors e-mail: markus.fiedler@bth.se
Language: English
Abstract: Given the growing importance of quantitative relationships between user-perceived Quality of Experience (QoE) and network Quality of Service (QoS), this paper investigates the IQX hypothesis for two voice codecs, iLBC and G.711. This hypothesis expresses QoE as an exponential function of QoS degradation. The experiments are carried out in a controlled environment using the softphone SJPhone, the network emulator NIST Net, and a tool calculating the PESQ (Perceptual Evaluation of Speech Quality) from sent and received audio files. The IQX hypothesis is confirmed exactly for disturbances perceived on applications level, packet loss and packet reordering, which clearly correlate to the main sensitivities of the used softphone to packet-level disturbances such as loss, jitter and reordering. So, besides of providing a unified relationship between QoE and QoS, the IQX also proved to be capable of identifying the QoS parameters of relevance for QoE degradations. The study also points out interesting tracks for future work in terms of QoS degradations and related QoE evaluations.
Summary in Swedish: Pappret belyser den exponentiella påverkan av tjänstekvalitetsstörningar (såsom dataförlust, fördröjningar och reordering) på upplevt tjänstekvalitet, fokusserat på populära röst-kodningsalgoritmer såsom G.711 och iLBC (som används av Skype). QoS, QoE, upplevt tjänstekvalitet, mätningar, nätverksemulering
Subject: Telecommunications\General
Computer Science\Networks and Communications
Keywords: IQX hypothesis, QoS, QoE, measurements, VoIP, iLBC, G.711, network emulation, NIST Net
Note: Published in: 18th ITC Specialist Seminar on Quality of Experience http://www.bth.se/fou/forskinfo.nsf/3efcc0263496fe93c125681f0031bfd0/3640415508145c5fc12574fe0052d5a4!OpenDocument