QoE Simulation Analysis of VoIP Traffic Support under Nakagami-m Fading Channels
Ramon Sanchez-Iborra, Maria-Dolores Cano, Joan Garcia-Haro
Signals and Telecommunication Journal, Vol. 2, No. 2, 2013.
DOI: 
Link: http://www.dline.info/stj/fulltext/v2n2/2.pdf
Abstract:
The expansion of the wireless networks is one of the main reasons of the doubtless growth of the VoIP communications during the last years. This technology has been extensively studied by the research community from several points of views, such as, (i) the effect of delay, packet loss rate, jitter, etc. on the quality of the VoIP calls, or (ii) the systems capacities evaluating different bandwidths and coding schemes. However, very few works detailing the effect of the wireless physical layer can be found in the related literature. In this work we employ the Nakagami-m propagation model in order to evaluate the effect of fading channels on VoIP traffic for IEEE 802.11 systems and its influence on the Quality of user Experience (QoE). The results obtained employing this propagation model, which permit us to characterize the wireless channel with different levels of hostility (fading), are compared with those attained in a Free Space environment. We simulate several scenarios, with different codecs, different packetization time-intervals, and different bandwidths in order to study the impact of fading over system capacity, coverage range, and QoE, which is estimated by the E-Model. From our results, we observe that fading channels provoke a noticeable decrease in the system maximum capacity and coverage range. Furthermore, VoIP communications suffer a noticeable drop on the achieved QoE in scenarios affected by fading channels, mainly affecting to low bit-rate codecs.