## 5 5G FWA Field Trials
### Performance Evaluation of FWA System
#### 5.4.5 Network Quality Evaluation
As most of the current services are multimedia-based, in this tutorial, we focus on the ITU-T G.1070 framework for the multimedia communication quality assessment model illustrated in Figure 20. The framework focuses on multimedia \(QoE\) and performance in which both generic and user-related aspects are considered. In this model, essential \(QoE/QoS\) planning strictures which are video and speech quality are the input parameters. Furthermore, it comprises three functions: speech quality estimation, video quality estimation, and multimedia quality integration functions. Note that the instigated degradation by pure delay is considered only in the latter function [357]. Additionally, the model offers three outputs (quality metrics): the multimedia quality (\(MM_{q}\)), the speech quality influenced by video quality (\(S_{q}\) (\(V_{q}\))), and the video quality influenced by speech quality (\(V_{q}\) (\(S_{q}\))). Furthermore, note that owing to variations in the coding parameter settings and decoder characteristics, a number of coding technology (e.g., MPEG-4 codecs) can be implemented. Based on this, this model exploits the existing tables prepared for each video and speech codec to determine the coefficients of video and speech quality estimation functions. Besides, the objective measurement of speech quality (\(S_{q}\)), \begin{table}
\begin{tabular}{l c} \hline \hline \multicolumn{1}{c}{**Experience**} & **Score** \\ \hline Bad & 1 \\ \hline Poor & 2 \\ \hline Fair & 3 \\ \hline Good & 4 \\ \hline Excellent & 5 \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Subjective mean opinion score evaluation. Figure 20: Multimedia communication quality assessment model (Adapted from [357]). video quality (\(V_{q}\)), and multimedia quality considering the influences of speech and video regarding quality and delay (\(MM_{q}\)) can be expressed, respectively, as [357]  
\[S_{q}=\left\{ \begin{array}{ll}1&\text{ if }Q<0\\ 1+0.035Q+Q(Q-60)(100-Q)7\times 10^{-6},&\text{ if }0<Q<100\\ 4.5&\text{ if }Q>100\end{array} \right., \tag{10a}\] \[V_{q}=1+l_{coding}\exp\left\{\frac{P_{p}l_{V}}{D_{p_{p}l_{V}}} \right\},\] (10b) \[MM_{q}=m_{1}MM_{SV}+m_{2}MM_{T}+m_{3}MM_{SV}MM_{T}+m_{4}, \tag{10c}\]  
where \(P_{p}l_{V}\) denotes the video packet-loss rate, \(D_{p_{p}l_{V}}\) is the degree of video quality robustness against packet loss, \(l_{coding}\) represents objective measurement of basic video quality accounting for coding distortion, \(MM_{SV}\) is the audio-visual quality, \(MM_{T}\) denotes the audio-visual delay impairment factor, \(Q\) is the speech quality index, and \(m_{i}\) are coefficients that dependent on the video display size and conversational task. Note that \(MM_{q}\) is constrained between 1 and 5. The audio-visual quality, \(MM_{SV}\), and the audio-visual delay impairment factor, \(MM_{T}\), are expressed as  
\[MM_{SV}=m_{5}S_{q}+m_{6}V_{q}+m_{7}S_{q}V_{q}+m_{8}, \tag{11a}\] \[MM_{T}=\max\{AD+MS,1\}, \tag{11b}\]  
where \(MS\) is the audio-visual media synchronization and \(AD\) denotes the absolute audio-visual delay are defined, respectively, as  
\[AD=m_{9}(T_{S}+T_{V})+m_{10}, \tag{12a}\] \[MS=\left\{ \begin{array}{ll}\min\{m_{11}(T_{S}-T_{V})+m_{12},0\}& \text{ if }T_{S}\geq T_{V}\\ \min\{m_{13}(T_{V}-T_{S})+m_{14},0\}&\text{ if }T_{S}<T_{V}\end{array} \right., \tag{12b}\]  
where \(T_{S}\) and \(T_{V}\) are the speech and video delays, respectively.