IVHS and broadcasting: Applications and opportunities

The intelligent vehicle/highway system (IVHS) concept needs significant radio spectrum if it is to succeed. Driven by this need, the IVHS community discovered subcarriers on broadcast stations as potential one-way communications channels. Broadcast signals cover North America with a high positive correlation between population density and usable signals. Broadcast subcarriers are a unique medium with engineering tradeoffs unfamiliar to most communications engineers. The technical aspects of broadcast subcarriers on FM, AM and television stations are explored from an historical, current and future viewpoint. Differences in broadcast styles around the world and their potential impact on subcarrier operation are discussed.