The MCSE Methodology

The MCSE methodology (Méthodologie de Conception des Systèmes Electroniques, also known as CoMES -Co-design Methodology for Electronic Systems) is based on a top-down design process.

A design process consists of a series of steps that transform an input (specifications) into an output (solution)
passed as input to the next step. The organization of the steps is done according to a design process model.
Several process models have been suggested and experimented: waterfall model, V model, spiral model, contractual model, etc. If any design process model can be defined and applied, it is crucial that the meaning, goal, inputs and outputs for each step are clearly defined.

The MCSE design process organizes the required steps in a top-down manner. Designers can work simultaneously on several steps given that they respect dependencies between steps and design choices. The flow is not continuous as additional verification activities, resulting in a backward flow, are necessary to correct and/or enhance solutions.
System designers proceed according to a minimum of 5 steps:
1. Requirements definition
2. System specification
3. Functional design
4. Architectural design
5. Prototyping
In addition, the MCSE design process enables design traceability as well as IP capitalization and reuse at every
design stage.
Forward and backward traceability between steps is enforced to:
- Capture the relations between initial requirements and all subsequent design models;
- Manage potential changes in requirements.

Capitalization and reuse are essential activities for a correct and efficient use of IP components. Reusing components is useful during functional and architectural design, but also during prototyping. It helps designers shorten the design process.

It is facilitated in two ways:
- Outside-in: identifying external functional or architectural components that satisfy the required functionality and are interconnectable;
- Inside-out: identifying internal components of the solution under design to be reused in other projects.

To be reused, a component needs to be well-defined, correctly encapsulated, validated and conform to an interchange standard.

Requirements traceability is potentially a one-to-many relation between a requirement and elements of the design. It implies the ability to follow the whole design process in forward and backward directions. A correct record of traceability between requirements and system components enables customers and project managers to monitor progress in the project.

Requirements management deals with evolutive requirements. Modifications, changes, improvements and corrections in requirements are inevitable. Taking modifications into account is facilitated by a clear procedure applied to the whole design process and by appropriate tools.