Design and Implementation Issues of Soft IP for All-Digital Broadband Modems

摘要

This paper will briefly overview common modulation schemes and digital realizations from an implementation viewpoint. Concepts and issues commonly encountered in ASIC-based implementations of broadband communications systems will be highlighted. An intellectual-property-based design flow will be described which offers the turn-around necessary to keep pace with the emerging broadband communications market. The tremendous market potential for low-cost broadband communications in the home has fueled increased activity around digital implementations of various modulation schemes. There are several viable transmission media for delivering broadband digital communications services into the home: satellite, cable, twisted-pair copper, HFC, wireless local loop, and terrestrial communications channels. In addition, there are many types of modulation schemes being explored for these various applications. Each of these schemes has alternative implementations and design issues specific to the intended application. Further complicating the implementation issue is a plurality of emerging standards which specify differing physical layer requirements. Market pressures dictate very short design cycles in response to new standards. This situation strains the capabilities of traditional top-down ASIC design methods to a point where alternative flows are becoming commonplace: intellectual property (IP) based flows.