Single Frequency Networks in Digital Radio

Not too surprisingly, a Digital Radio Single Frequency Network (SFN) shares the same properties as a Digital Television SFN. For this reason some of this paper has been taken from [1]. The main differences between radio and TV SFN are due to the different S/N requirements and guard intervals. SFNs do offer significant potential advantages including better coverage, less interference, less power, higher reliability and a more efficient spectrum use. These properties are derived from basic propagation models. Potential problems that must be considered, and are specific to SFNs, are discussed. They all relate back to receiver performance. In addition, some basic discussion about how antenna patterns can be used to combat delay problems is included. The “hybrid” mode of HD Radio has some significant differences in its requirements for SFN distribution since both the digital and analog components must be considered. For a digital-only SFN overlaid on the coverage area of a hybrid FM station, there would still be analog implications to consider. Since hybrid transmission is likely to be the reality for many years to come, it raises special issues on which we elaborate later in the paper.