Improving the standard coding system for deep space missions

The European Space Agency (ESA) and the US National Aeronautics and Space Administration (NASA) are currently using a concatenated coding system consisting of an outer (255,223) Reed-Solomon code in the Galois field GF(2/sup 8/) and an inner rate R = 1/2 convolutional code with memory M = 6 for the transmission of images in deep space missions. Improvements of the standard coding system which can be separated in two groups are presented. The first group is composed of modifications concerning only the receiver, which can be used in current missions, such as the Galileo Mission, where every tenth of a decibel is needed. The second group comprises additional modifications on code parameters at the transmitter side and should be viewed as recommendations for future deep space missions. In the first group, additional coding gains of about 0.3 dB to 0.4 dB, and, in the second group, of about 0.6 dB to 0.9 dB can be achieved compared to the standard coding system. The increase of complexity is only in the receiver, not in the spacecraft.<<ETX>>