Refinements of Rent's rule allowing accurate interconnect complexity modeling

The complexity of the interconnect topology of a circuit is well captured by Rent's rule. This rule can be applied for a priori wire-length estimation, which is useful for improving the quality of generated layouts, and could be used for reducing the number of design iterations. It can also successfully be applied for the generation of synthetic benchmark circuits. However Rent's role is an empirical approximation, and there are many deviations. This paper describes possible extensions to Rent's rule and discusses some of its applications.