# A Model-Based Engineering Approach for Evaluating Software-Defined Radio Architecture
## 5 Multi-Criteria Decision-Making Analysis
The next step is to compare the criteria in pairs and assign relative weights to each criterion based on its importance relative to the other criterion. The experts make pairwise comparisons, and then the answers are consolidated and normalized into a set of weights. Then, the options or alternatives are assessed against each criterion using relative weights derived through expert elicitation. Finally, the scores for each option are combined across all criteria, using the relative weights assigned to the criteria to adjust the scores. A decision is then made by comparing the overall scores for each option. The AHP utilizes a technique called pairwise comparison to assign relative importance to different criteria or options. The pairwise comparison involves comparing each criterion or option with every other criterion or option, and assigning a rating based on the relative importance of one element compared to the other. The commonly used rating scale for pairwise comparison includes a range of values such as 1 to 9, where 1 indicates equal importance, 3 indicates moderately more important, 5 indicates strongly more important, 7 indicates very strongly more important and 9 indicates extremely more important. Additionally, intermediate values can be used to indicate importance levels between any two of these ratings that the relative importance between two criteria or options is not extremely different or extremely similar, but somewhere in between. It is important to use the scale consistently throughout the process and avoid arbitrary values or personal biases while comparing criteria or options. By using pairwise comparison in a systematic and consistent manner, the decision maker can ensure that the relative weights assigned to the criteria or options are accurate and reliable [32; 33]. It is important to note that a consistency check of the pairwise comparisons is critical to ensure the accuracy of the final decision. One measure of consistency is the Consistency Ratio (CR), which can be used to determine if the judgments of the evaluators are consistent. According to [33], a CR of 0.1 or less is considered acceptable and indicates that the judgments of the evaluators are consistent. Therefore, the decision maker should check the CR and ensure that it meets this threshold before making a final decision. The AHP process helps to make trade-off decisions between conflicting requirements. Having multiple individuals participate in the completion of AHP pairwise comparison matrices can lead to reduced bias and improved accuracy of results. This approach also allows for various perspectives to be considered, resulting in a more comprehensive decision-making process [32; 33; 34]. Therefore, we asked three SMEs to complete the pairwise survey. One SME is a university professor who instructs courses related to System Engineering, while the other two SMEs are industry representatives from the aerospace sector, one having extensive practical design experience with communications. In the assessment process, the importance of various criteria to stakeholders and the alternative priorities were quantified using pairwise comparisons from three SMEs. For the four criteria, a \(4\times 4\) square pairwise comparison matrix A was created. In this matrix, each entry \(a_{ij}\) represents the relative importance of criterion \(i\) over criterion \(j\), rated on a scale of 1 to 9. To calculate the weights of the criteria, matrix \(A\) was first normalized by dividing each element \(a_{ij}\) by the sum of its respective column, as defined by Equation (10). The average row scores (ARS) were then calculated using Equation (11), approximating the eigenvector of the pairwise comparison matrix, the results of which are presented in Table 3. This process was carried out for each SME. Similarly, for the three architectural alternatives and four assessment criteria, four 3 \(\times\) 3 matrices were created for each SME. This was performed to determine the priority (or score) for each alternative architecture against each criterion.