Coding and modulation techniques for high speed data services by satellite

Data traffic in satellite systems is likely to increase, similar to the trend in terrestrial systems. In particular, demand for high speed data services will increase. These new services require more power and bandwidth than is currently required for speech and low rate data/fax services. High order modulation schemes such as 8 PSK and 16 QAM, when combined with turbo coding provide a good solution in terms of both power and bandwidth efficiency. Moreover, the low operating signal to noise ratio (SNR) of such schemes increases their robustness to interference and distortion. Key issues such as delay, complexity and performance are discussed indicating that significant gains are possible for current and future high speed data services provided by satellite.