# Error Resilient Coding Techniques for Video Delivery over Vehicular Networks
## 5 Real Scenarios Evaluation
### Analysis of Results
#### 5.2.3 Background Traffic Conditions without FEC Protection  
In this section, we present the results of the tests for a moderate and a high background traffic loads.  
In Table 6, the PLR and TLR values for the bit streams without FEC protection, averaged for all the encoding modes in the three zones under consideration, and under both traffic loads, are shown. It can be generally observed that, as the number of tiles per frame increases, the PLR value diminishes, and again, the poor performance of layouts with a low number of tiles per frame appears.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Zone I**} & \multicolumn{2}{c}{**Zone II**} & \multicolumn{2}{c}{**Zone III**} \\ \cline{2-7}
**62 pps/512 B** & **PLR** & **TLR** & **PLR** & **TLR** & **PLR** & **TLR** \\ \hline
1 til/frm & 7.82\% & 28.10\% & 16.87\% & 40.21\% & 27.32\% & 43.55\% \\
2 til/frm & 6.80\% & 14.56\% & 15.42\% & 26.06\% & 26.60\% & 34.14\% \\
4 til/frm & 5.49\% & 7.44\% & 13.77\% & 17.16\% & 25.65\% & 28.04\% \\
6 til/frm & 4.43\% & 5.13\% & 12.15\% & 13.49\% & 24.72\% & 25.33\% \\
8 til/frm & 3.73\% & 4.00\% & 10.99\% & 11.68\% & 24.01\% & 24.22\% \\
10 til/frm & 3.26\% & 3.42\% & 9.94\% & 10.34\% & 23.56\% & 23.61\% \\ \hline \hline \multicolumn{7}{c}{**Zone I**} & \multicolumn{2}{c}{**Zone II**} & \multicolumn{2}{c}{**Zone III**} \\ \cline{2-7}
**125 pps/512 B** & **PLR** & **TLR** & **PLR** & **TLR** & **PLR** & **TLR** \\ \hline
1 til/frm & 14.32\% & 44.63\% & 24.89\% & 54.02\% & 31.26\% & 54.17\% \\
2 til/frm & 14.01\% & 28.43\% & 24.71\% & 39.85\% & 30.78\% & 42.24\% \\
4 til/frm & 12.68\% & 16.88\% & 24.03\% & 29.37\% & 29.69\% & 33.40\% \\
6 til/frm & 10.69\% & 12.35\% & 21.75\% & 23.92\% & 27.65\% & 28.84\% \\
8 til/frm & 8.82\% & 9.52\% & 19.52\% & 20.53\% & 26.68\% & 27.16\% \\
10 til/frm & 7.43\% & 7.79\% & 17.80\% & 18.35\% & 25.82\% & 25.97\% \\ \hline \hline \end{tabular}
\end{table}
Table 6: PLR and TLR for non-protected bit streams under 62 pps and 125 pps background traffic conditions for zones I, II and III for every til/frm layout averaged over all the encoding modes.  
In Zone I, the PLR obtained is exclusively due to background traffic (for this zone in the absence of background traffic, a PLR value of 0% is obtained). Only when using six or more tiles per frame with a 62 pps background network load, the TLR values keep under reasonable limits. The quality of video sequences for this zone at moderate background traffic loads is depicted in Figure 10(a). The LP, IPs, and IPX25 pctCTU encoding modes show poor performance, in line with the previous tests. The IPIP encoding mode turns out to be the most effective (for a high number of tiles per frame). For dense traffic conditions, 125 pps (Figure 10(b)), nearly all of the PSNR values for the different modes and til/rm layouts are under 29 dB and are considered of very low quality. So, for dense traffic conditions, FEC protection becomes mandatory.  
In Zone II and Zone III, the PLR value results from the combination of isolated packet losses and bursty packet losses. The high TLR values for these two zones clearly show that all the bit streams received in these two zones are completely useless, since the received packets produce very low quality video sequences.