## 3 Spectrum Management for CR-VANET Using MCDM
### Channel Decision Based on Channel Ranking
#### 3.2.2 Qualitative Analysis for AHP
Due to the high mobility of cars, identifying the available network and routing of vehicles is a critical task that can be performed using vertical handoff and the OpenFlow SDN controller. DAHP-TOPSIS is used to analyze the packet delivery ratio and channel selection for CR-VANET by comparing it to other techniques, such as DAHP-TOPSIS, DAHP-MOORA, DAHP-SAW, random packet loss, and rank-based channel selection. Proposed DHAP-TOPSIS has been validated along with parallel competing techniques in the MCDA domain. Due to the speed and route failure of the vehicle in terms of low traffic of 0.2 and high traffic of 0.6, the decision of rank-based channel selection and packet delivery ratio fluctuates from time to time. CR-VANET delivers various data services, such as audio, video, and text, on roughly 20 to 200 channels in various scenarios. Text services perform better in the CR-VANET than audio and video services when employing DAHP-TOPSIS, and they cost less than audio and video services. Tables 20 and 21 provide the findings on the number of handoff conditions and computation time in the CR-VANET. The proposed DAHP-TOPSIS system employs CR-VANET to provide communication to vehicle users. It may be used to address a variety of societal and environmental issues, including traffic congestion control, safety applications, such as driver assistance and automatic crash area notification, and transportation safety in handoff circumstances using an SDN-controlled vehicular network. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline  & & & \multicolumn{10}{c}{**Number of Spectrum Handoffs**} \\ \cline{3-13}
**PU Traffic** & **Service Type** & \multicolumn{3}{c}{\begin{tabular}{c} **DAHP–TOPSIS** \\ **No. of Channels** \\ \end{tabular} } & \multicolumn{3}{c}{\begin{tabular}{c} **DAHP–SAW** \\ **No. of Channels** \\ \end{tabular} } & \multicolumn{3}{c}{\
\begin{tabular}{c} **DAHP–MOORA** \\ **No. of Channels** \\ \end{tabular} } & \multicolumn{3}{c}{
\begin{tabular}{c} **Random** \\ **No. of Channels** \\ \end{tabular} } \\ \cline{3-13}  & & **20** & **100** & **200** & **20** & **100** & **200** & **20** & **100** & **200** & **20** & **100** & **200** \\ \hline \multirow{3}{*}{Low Traffic (0.2)} & Text & 295 & 257 & 239 & 318 & 277 & 257 & 251 & 218 & 203 & 452 & 393 & 365 \\  & Audio & 339 & 295 & 274 & 365 & 317 & 295 & 288 & 250 & 233 & 519 & 451 & 419 \\  & Video & 395 & 346 & 320 & 424 & 372 & 345 & 377 & 332 & 309 & 598 & 521 & 485 \\  & Text & 577 & 482 & 455 & 622 & 519 & 490 & 488 & 407 & 384 & 891 & 744 & 702 \\  & Audio & 653 & 545 & 514 & 704 & 587 & 554 & 552 & 461 & 434 & 1007 & 841 & 794 \\  & Video & 865 & 725 & 684 & 929 & 780 & 736 & 825 & 692 & 652 & 1325 & 1109 & 1048 \\ \hline \hline \end{tabular}
\end{table} 
Table 21: Various handoff processes for comparing traffic, data service and channel size decision. Figure 10: Channel selection vs. handoff schemes for PU low traffic = 0.6. **Author Contributions:** V.D.K. and M.A., writing, original draft preparation, designing, analysis, editing. L.J., I.U., D.I. and O.G., review, editing, investigation. All the authors also contributed to writing, reviewing, and structuring the work. All authors have read and agreed to the published version of the manuscript. **Funding:** No funding was involved in this research. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** Not applicable. **Conflicts of Interest:** The authors declare no conflict of interest. ## References

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