Performances of Low SNR DVB-RCS Modem Suing Test Frequency Algorithm

Burst demodulation at low signal to noise ratio represents a key issue, especially for satellite return link MF-TDMA access. Besides inherent coding performances, modem implementation losses and reference symbol overhead have to be minimized for a system efficiency objective. This paper presents a new demodulation algorithm, called test frequency, and its implementation in a modem prototype called "turbocode mock-up". The measured performances of this modem applied to a DVB-RCS (digital video broadcasting - return channel by satellite) transmission scheme are presented for realistic channel conditions. The reference symbol dimensioning and positioning are discussed, and recommendations for DVB-RCS standard evolutions are proposed