Design, Performance Evaluation And Comparison Of Turbo Codes And Bch Codes For Telecommand Applications

increased bit rates (up to some hundreds of kbit/s) and limited link budgets. The only error correcting code currently included in the Consultative Committee for Space Data Systems (CCSDS) [1] and the European Cooperation for Space Standardization (ECSS) [2] recommendations for TC links is the BCH(63, 56) code. In order to improve such TC coding, substantial work has been recently done within CCSDS Working Groups, to investigate solutions that take into account the recent progress in channel coding. Among the most attractive options that can be considered for upgrading TC coding, a prominent role is certainly played by Low-Density Parity-Check (LDPC) codes, proposed both in binary and non-binary form. Indeed, LDPC codes show very good performance, not far from the theoretical limits. In this paper we present a study on parallel turbo codes and soft-decoded BCH codes, as possible alternatives to LDPC codes. We show that both these schemes are highly competitive against LDPC codes for TC applications. Turbo codes (which are already part of the CCSDS Telemetry recommendation) are very close to non-binary LDPC codes. BCH codes can be soft-decision decoded by applying the Most Reliable Basis (MRB) algorithm, providing nearly optimal performance, superior to LDPC iterative decoding performance. The MRB algorithm can be usefully applied to short LDPC codes, too: its advantages and disadvantages are discussed. This paper is focused on new results in Additive White Gaussian Noise (AWGN) channel. A companion paper [3] presents results under jamming, i.e., intentional interference.