TDM framing for gap filler operation in satellite digital multimedia broadcasting System A

A new satellite digital multimedia broadcasting system is proposed which deploys an additional time division multiplexing (TDM) signal path for gap filler operation over System A. All orthogonal frequency division multiplexing (OFDM) ensembles of System A are multiplexed into one TDM frame with some header information. The OFDM frame boundary is used for the reference of TDM framing. This TDM frame is encoded, interleaved, and modulated once more. Both multiple OFDM signals and one TDM signal are transmitted through separate frequency bands. The proposed system can configure an efficient and flexible complementary terrestrial gap filler system by introducing a mode conversion gap filler which receives the TDM signal through Ku-band and transmits multiple OFDM signals through S-band. This proposed gap filler does not have an oscillation problem inherently and does not degrade the signal quality. It is shown that it is recommended to deploy a large number of gap fillers with low gain power amplifiers rather than a small number of gap fillers with high gain power amplifiers.