Bus-based System Design
A 'bus-based system' is the term used to describe a method of connecting functional 'building blocks' of logic into an overall system, using generic buses. In this way, you can quickly assemble a system that incorporates a diverse range of functionality, and that will meet the needs of your intended application.
In Altium Designer, such a system is built using the Wishbone bus interconnect and can be implemented as a high-level, abstract, OpenBus System document, or at the low-level, using Wishbone-compliant components placed on schematic sheets. OpenBus Systems are the favored approach as they provide an environment in which to build your system that is highly intuitive, streamlined and less prone to error.
Figure 1. Example bus-based systems in Altium Designer - OpenBus System-based (top) and Schematic-based (bottom).