Single frequency networks in DTV

Single Frequency Networks (SFNs) offer many advantages including better coverage, less interference, less power, and higher reliability. SFNs can also free up extra TV channels, resulting in more efficient use of the spectrum. The paper presents an overview of the advantages of SFNs and some basics about how to implement them. The significantly improved Signal to Interference performance and less radiated power in SFNs are derived from simple propagation models. Some potential problems that must be considered are discussed, including limitations due to receiver performance. Several simple formulas that should be helpful in quickly estimating and evaluating an SFN system are also presented. Finally, the likely implications of SFNs are covered, in particular the need for changed FCC rules and increased competition through a higher frequency reuse. The idea of the FCCs only limiting the power outside of the service area and letting the broadcasters decide on transmitter locations, number of transmitters and power levels is proposed.