CONCATENATED CODING FOR LOW DATE RATE SPACE COMMUNICATIONS

Abstract

In deep space communications with distant planets, the data rate as well as the operating signal-to-noise ratio may be very low. To maintain the error rate also at a very low level, it is necessary to use a sophisticated coding system (longer code) without excessive decoding complexity. The concatenated coding has been shown to meet such requirements in that the error rate decreases exponentially with the overall length of the code while the decoder complexity increases only algebraically. Three methods of concatenating an inner code with an outer code are considered. Performance comparison of the three concatenated codes is made. It is shown that the concatenated code with inner code a convolutional code and outer code a Reed-Solomon code performs the best among the three.