# A Model-Based Engineering Approach for Evaluating Software-Defined Radio Architecture
## 2 Descriptive Models  
[PERSON] et al. [2017] compared six widely recognized MBSE methodologies, IBM's Rational Unified Process for System Engineering, NASA Jet Propulsion Lab's State Analysis, Dori's Object-Process Methodology, IBM's Harmony-System Engineering, Vitech's MBSE, and INCOSE's Object-Oriented Systems Engineering Method (OOSEM). The OOSEM, which covers both software and hardware development within a single framework, was found to be well suited for modeling complex and multi-domain systems. Additionally, it utilizes a standardized, iterative, and recursive procedure that aligns with the systems engineering Vee process model, making it ideal for system modeling at each level of system abstraction. Due to the complex and multi-disciplinary engineering nature, including both software and hardware, of the SDR-MM, the OOSEM Specify and Design System process described in [20] was selected to develop the descriptive model for this problem. The OOSEM is a comprehensive approach to systems engineering that is based on a top-down, scenario-driven methodology. This method uses SysML to support the various stages of systems development. It encompasses key systems engineering activities such as model set-up, stakeholder needs analysis, use case definition, system requirements analysis, logical and physical architecture definition, optimization and evaluation of alternatives, management of requirements traceability, and system verification and validation. These activities help ensure that the final system meets the stakeholders' needs and is effective in achieving its goals. Before starting the Analyze Stakeholder Needs process, a Concept of Operation (CONOP) or multiple CONOPs would have been prepared describing the assumptions or intent regarding the enterprise's overall operation or series of operations. The main activities of OOSEM are summarized below [21; 25; 26]. _Model Set-up._ This step involves organizing the model using a SysML package diagram, which includes the analysis of stakeholder needs, system requirements, the definition of the logical and physical architecture, and traceability of requirements. This step also includes defining modeling conventions and standards to maintain a consistent appearance and approach to modeling. _Analyze Stakeholder Needs._ In this step, based upon the CONOPs, stakeholders are identified, their problems are analyzed and understood, external systems and users are identified, and top-level use cases and MOEs are defined. _Analyze System Requirements._ This step involves specifying the functional requirements, interfaces, critical system properties, performance characteristics, and design constraints. High-level (enterprise) use cases from the previous step can be modeled and analyzed, and an IBD can be created to describe the system's interactions with other systems. _Define Logical Architecture._ The process of defining a logical architecture involves creating a comprehensive overview of the system, including its functional components, their interactions, and relationships. This step also involves breaking down functions and assigning them to the logical elements of the system for better clarity and organization. Further information about this stage can be found in Section 4. _Synthesize Candidate Physical Architectures._ This step involves converting the logical architecture into physical components and subsystems. It also entails specifying the physical connections between components and the physical relationships between them, making sure they are aligned with the established requirements and the CONOPs. For more information about this step, refer to Section 4. _Optimize and Evaluate Alternatives._ The analysis is conducted to determine the best system architecture that meets the requirements and has the best MOEs. This step is used throughout Sections 4 and 5. The OOSEM also includes requirement traceability to ensure that the solutions meet the needs and fulfill the requirements.