Introduction

Due to the complexity of modern communication systems and the environment in which they are deployed, standard analytical techniques must be supplemented by computer-aided techniques in the design and testing process. Properly developed simulations are much like a hardware testbed in that they can be used to support system development in the following areas:

• to collect waveforms at various points in the system in order to validate performance and to gain insight into system operation,
• to perform parametric studies,
• to test design alternatives (play “what if” games), and
• to evaluate overall system performance.

A properly developed simulation requires the following:

• models must be valid,
• the simulation methodology must be correct and appropriate for the problem under study,
• the simulation code must be validated, and
• the overall simulation must be sanity checked.

The most important and error-prone part of this process is model development. Models of hardware can sometimes be based on the mathematical equation of the process implemented by the hardware. However, in many circumstances the hardware model must be developed from measurements of the input-output characteristics of the hardware being measured. The measurements must be obtained over the ranges of voltage, current, power, temperature, frequency, etc., that reflect the operating environment of the hardware.

Modeling and simulation methodologies are fundamental tools that are used in most research efforts at MPRG. However, modeling and simulation are research activities in their own right, and projects with both industry and government have been granted to MPRG for the purpose of developing modeling and simulation methodologies. In addition, in the important area of software radios the boundary between the simulation of the radio and the hardware that implements the radio is blurred since the simulation of the radio, when downloaded to the appropriate chip sets, becomes the radio.