Introduction
From time to time, marshalling events occur in stable markets placing difficult new requirements on established system designs. Subsequently, innovative new design tools and processes emerge to address shortcomings in the legacy design flows for the established systems. In the case of wireless systems, the emergence of coexistence represents one of these marshalling events. In particular, the connectivity boom in consumer electronics and the importance of electronic warfare in military environments is requiring radios to perform in spectrally rich environments. As a consequence, system simulation is emerging as a necessary complement to static analysis for designing wireless systems.
Wireless Communication System Design
Wireless communications systems engineers fill the gap between product managers who define product requirements and component design engineers who implement designs to meet a set of specifications. The system engineer’s primary role in the product development process is to select a design architecture capable of meeting the product requirements and to define a set of specifications for the component design teams. The difficulties, and subsequent need for design tools, arise when the product requirements dictate architectures containing coupled subsystems.
Most wireless receiver designs are modular by nature. Figure 1 illustrates a modular low-IF design suitable for narrow band personal area networking (PAN) applications. In the figure, the critical subsystems represent three distinct signal processing disciplines: digital baseband (blue), analog baseband (green), and RF bandpass (orange). Although the design is modular, from the system engineer’s point of view all of the subsystems are coupled by two critical mechanisms: noise and interference.