DVB-S2 LDPC Decoding Using Robust Check Node Update Approximations

Broadband satellite services to fixed terminals are currently offered in the forward link by the 2nd generation (2G) digital video broadcasting satellite (DVB-S2) standard. For this standard the use of powerful low-density parity-check (LDPC) error correcting codes has been adopted performing within approximately 1 dB from the Shannon capacity limit. This paper studies and compares for the first time in a systematic manner different approximation methods used in check node update computation of DVB-S2 LDPC decoding with the aim of reducing computational complexity. Various performance evaluation results are presented for a wide range of DVB-S2 parameters, such as LDPC codeword size, coding rate, modulation format and including several decoding algorithms. It is shown that the proposed check node update approximations have a robust behavior, i.e. the resulting performance is quite independent of the DVB-S2 modulation and coding parameters. It is further shown that these approximations perform very close to the optimal sum-product algorithm (SPA) in degradation, which is less than 0.2 dB. Despite this small degradation, the reduction in computational complexity compared to the optimal SPA is significant and can be as high as 40% in computational time savings.

[1]  Mustafa Eroz,et al.  DVB‐S2 low density parity check codes with near Shannon limit performance , 2004, Int. J. Satell. Commun. Netw..

[2]  Jian Song,et al.  Technical Review on Chinese Digital Terrestrial Television Broadcasting Standard and Measurements on Some Working Modes , 2007, IEEE Transactions on Broadcasting.

[3]  Rüdiger L. Urbanke,et al.  The capacity of low-density parity-check codes under message-passing decoding , 2001, IEEE Trans. Inf. Theory.

[4]  Riccardo De Gaudenzi,et al.  DVB‐S2 modem algorithms design and performance over typical satellite channels , 2004, Int. J. Satell. Commun. Netw..

[5]  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.

[6]  Dae-Ik Chang,et al.  Low computational complexity algorithms of LDPC decoder for DVB-s2 systems , 2005, VTC-2005-Fall. 2005 IEEE 62nd Vehicular Technology Conference, 2005..

[7]  Frank Kienle,et al.  A synthesizable IP core for DVB-S2 LDPC code decoding , 2005, Design, Automation and Test in Europe.

[8]  Robert G. Gallager,et al.  Low-density parity-check codes , 1962, IRE Trans. Inf. Theory.

[9]  Alberto Morello,et al.  DVB-S2: The Second Generation Standard for Satellite Broad-Band Services , 2006, Proceedings of the IEEE.

[10]  Vincent Berg,et al.  Low cost LDPC decoder for DVB-S2 , 2006, Proceedings of the Design Automation & Test in Europe Conference.

[11]  Pascal Urard,et al.  Based on 64800b LDPC and BCH Codes , 2005 .

[12]  Niclas Wiberg,et al.  Codes and Decoding on General Graphs , 1996 .

[13]  Ajay Dholakia,et al.  Reduced-complexity decoding of LDPC codes , 2005, IEEE Transactions on Communications.

[14]  Giovanni Giambene,et al.  Towards the Revision of DVB-S2/RCS Standard for the Full Support of Mobility , 2006 .

[15]  Stefano Cioni,et al.  On the adaptive DVB-S2 physical layer: design and performance , 2005, IEEE Wireless Communications.

[16]  D.J.C. MacKay,et al.  Good error-correcting codes based on very sparse matrices , 1997, Proceedings of IEEE International Symposium on Information Theory.

[17]  Barry G. Evans,et al.  Modified sum-product algorithms for decoding low-density parity-check codes , 2007, IET Commun..

[18]  Jun Sun,et al.  An Introduction of the Chinese DTTB Standard and Analysis of the PN595 Working Modes , 2007, IEEE Transactions on Broadcasting.

[19]  Sae-Young Chung,et al.  On the design of low-density parity-check codes within 0.0045 dB of the Shannon limit , 2001, IEEE Communications Letters.

[20]  Takashi Yokokawa,et al.  A Low Complexity and Programmable Encoder Architecture of the LDPC Codes for DVB-S2 , 2006 .

[21]  Robert Michael Tanner,et al.  A recursive approach to low complexity codes , 1981, IEEE Trans. Inf. Theory.

[22]  M. Luby,et al.  Improved low-density parity-check codes using irregular graphs and belief propagation , 1998, Proceedings. 1998 IEEE International Symposium on Information Theory (Cat. No.98CH36252).