# A Model-Based Engineering Approach for Evaluating Software-Defined Radio Architecture
## 2 Descriptive Models
However, based on stakeholder needs and operational concepts, we depict expected interactions, inputs, and outputs to and from the system in the environment. MOEs, which capture essential performance and lifecycle considerations, are used to define measurable outcomes that stakeholders expect to achieve when the SOI is integrated into its operating environment. The initial set of 20 requirements (Table 1) was narrowed down to four key criteria. This reduction focused on independent criteria that uniquely distinguish each architecture, as many of the initial requirements were found to be 'common mode' factors that all architectures met, and thus did not serve as differentiators in the MCDM assessment. For the SDR-MM, MOEs of signal output bandwidth, total cost, total mass, and safe operating temperatures are defined. These criteria will be described in the following paragraphs. _SDR-MM Cost (USD)_: This is the total estimated material and labor cost (money spent) to manufacture the SDR-MM. Manufacturing cost (MC) includes the cost of Commercial-Off-The-Shelf (COTS) hardware (HW), assembly cost, and software (SW) programming cost. The SW cost here is non-recurring engineering to load operational SW into the system. The cost of manufacturing the SDR-MM Enclosure was estimated using the DFMA software (version 2021A) by [PERSON] [27]. The tool requires basic geometry information, such as envelope shape and dimensions, and the number and dimension of features (holes, cuts, etc.). It also requires defining the material and manufacturing processes. If applicable, the cost of the thermal solution hardware and labor for the SDR-MM are added. \[MC(\text{USD})=C_{HW}+C_{enc}+C_{thr-sol}+C_{assy}+C_{SW} \tag{1}\]  
where \(C_{HW}\), \(C_{enc}\), \(C_{the-sol}\), \(C_{assy}\), and \(C_{SW}\) are cost of COTS HW, Enclosure, thermal solution, assembly, and SW, respectively. _SDR-MM Mass (kg)_: This is the total mass (M) of SDR-MM elements, including connectors, power, signal, and data internal wires and cables, Enclosure, RF tuner, Analog to Digital Converter (ADC), Field-programmable Gate Array (FPGA), and miscellaneous electrical components and mounting HW. If applicable, it also includes the mass of a thermal solution. \[M(kg)=M_{enc}+M_{the-sol}+\sum_{i=1}^{n}M_{i} \tag{2}\]  
Figure 3: Activity diagram depicting SDR-MM behavior in its context and environment. where \(M_{enc}\) and \(M_{the\text{-}sol}\) are mass of Enclosure, and thermal solution, respectively, and \(i\) represents the remaining SDR-MM elements. _Signal Processing Performance:_ Number of Equivalent Narrow Bandwidth (NB) Outputs. This refers to the number of equivalent output channels capable of generating NB signals for processing in the external processor. The number of NB output channels determines the number of spectral range of signals that can be received simultaneously. Note: The signal analysis section has more detail on how to calculate this criterion. _SDR-MM Reliability:_ Average Electronic Surface Temperature (AEST). The AEST refers to the average temperature of the electronic components of an SDR-MM. It is used as an indicator of the system's thermal performance and can help predict potential thermal failures. Electronic components must be operated within a certain temperature range to maintain optimal performance, prevent damage, and achieve design life. The AEST measures how close the system or device is to reaching that limit. AEST is often used in the thermal management of electronic systems to ensure that the systems operate within safe temperature ranges. Note: The thermal analysis section has more detail on how to calculate this criterion.