ABSTRACT
The system’s spectral efficiency can be improved significantly if multiple transmitters employ the same frequency. Frequencies used in a cell will not be allocated in adjacent cells. As an alternative, Single frequency networks (SFN) broadcasting systems, where several transmitters transmit the same signal simultaneously and over the same bands, can be employed. To deal with the severe distortion inherent to SFN, digital broadcasting standards such as digital video broadcasting and digital audio broadcasting use Orthogonal Frequency-Division Multiplexing (OFDM) modulations which are known to be suitable for severely time-dispersive channels. Typically the SFN systems employ a large number of OFDM subcarriers, to ensure that the guard interval is large enough to cope with the maximum delay spread that can be handled by receivers. The chapter considers OFDM-based broadcasting systems with SFN operation and proposes an efficient channel estimation method that takes advantage of the sparse nature of the equivalent channel impulse response.
