A turbo/MAP decoder for use in satellite circuits

The implementation and performance of a turbo/MAP decoder is described. A serial block MAP decoder operating in the logarithm domain is used to obtain a very high performance turbo decoder. Programmable gate arrays and EPROMs allow the decoder to be programmed for almost any code from 4 to 512 states, rate 1/3 to rate 1/7 (higher rates are achieved with puncturing), and interleaver block sizes to 65,536 bits. Seven decoding stages were implemented in parallel. For rate 1/3 and 1/7 16 state codes with an interleaver size of 65,536 bits and operating at up to 356 kbit/s the codec achieved an E/sub b//N/sub 0/ of 0.32 and -0.30 dB, respectively for a BER of 10/sup -5/. BERs down to 10/sup -7/ were also achieved for a small increase in E/sub b//N/sub 0/.

[1]  D. Divsalar,et al.  Multiple turbo codes for deep-space communications , 1995 .

[2]  S. S. Pietrobon Implementation and performance of a turbo/MAP decoder , 1998 .

[3]  D. Divsalar,et al.  On the Design of Turbo Codes , 1995 .

[4]  A. Glavieux,et al.  Near Shannon limit error-correcting coding and decoding: Turbo-codes. 1 , 1993, Proceedings of ICC '93 - IEEE International Conference on Communications.

[5]  Sergio Benedetto,et al.  Unveiling turbo codes: some results on parallel concatenated coding schemes , 1996, IEEE Trans. Inf. Theory.

[6]  S. S. Pietrobon,et al.  A Simplification of the Modified Bahl Decoding Algorithm for Systematic Convolutional Codes , 1994 .

[7]  Alain Glavieux,et al.  Reflections on the Prize Paper : "Near optimum error-correcting coding and decoding: turbo codes" , 1998 .

[8]  Sergio Benedetto,et al.  Design of parallel concatenated convolutional codes , 1996, IEEE Trans. Commun..

[9]  Patrick Robertson,et al.  A comparison of optimal and sub-optimal MAP decoding algorithms operating in the log domain , 1995, Proceedings IEEE International Conference on Communications ICC '95.

[10]  S. S. Pietrobon Implementation and performance of a serial MAP decoder for use in an iterative turbo decoder , 1995, Proceedings of 1995 IEEE International Symposium on Information Theory.

[11]  Van Nostrand,et al.  Error Bounds for Convolutional Codes and an Asymptotically Optimum Decoding Algorithm , 1967 .

[12]  Daniel J. Costello,et al.  A Bandwidth Efficient Coding Scheme for the Hubble Space Telescope , 1991 .

[13]  Jean Yves Couleaud High Gain Coding Schemes for Space Communications , 1995 .

[14]  John Cocke,et al.  Optimal decoding of linear codes for minimizing symbol error rate (Corresp.) , 1974, IEEE Trans. Inf. Theory.