Iterativ decodierbare Codes und Anwendungen zu ungleichem Fehlerschutz
Zusammenfassung der Projektergebnisse
The present report describes the development of a multi-edge-type analysis of unequal error protecting low-density parity-check (UEP LDPC) and Luby transform (UEP LT) codes. Regarding UEP LDPC codes, such analysis gave rise to a more detailed description of the error-control performance of the different protection classes defined within a codeword. It also allowed the development of an optimization algorithm for the connectivity profile among the defined classes. Additionally, the developed algorithm enables the construction of UEP LDPC codes where the difference between the error rate performance of the protection classes can be adjusted by means of a single parameter. The optimized codes have a better performance than the ones already present in the literature for applications where either a low or high number of decoding iterations is needed. In addition, the developed optimization can generate codes with UEP capabilities which do not depend on the number of decoding iterations or on the parity-check matrix construction algorithm applied. Prior to our work, this feature was regarded as being dependent of the chosen parity-check matrix construction algorithm. Finally, we introduced a multi-edge analysis for UEP LT codes providing a general framework for the description of the techniques already present in the literature. Furthermore, we developed a novel construction algorithm for unequal error protecting LT codes and evaluated its performance by means of a multi-edge-type asymptotic analysis and finite-length simulations. Regarding the multi-edge UEP LDPC codes, a clear objective for further research is the application of our developed algorithm for data streams where more than two priority classes are defined. In this case, finite-length effects deserve further attention, since for a fixed blocklength the higher the number of protection classes, the lower is the number of bits within each one of them. Additionally, the investigation of codes with irregular check node degree distributions in conjunction with the optimization of the connections between protection classes can provide further room for performance improvement. Another possible investigation for both UEP LDPC and LT codes would be the development of an optimization algorithm that has a target bit error rate as optimization parameter. The results we present herein consist of new techniques that aim at improving the performance of systems where unequal error protecting LDPC and LT codes are desirable, e.g., packet based transmission, scalable video, and the transmission of videos or images compressed with layered source codes.
Projektbezogene Publikationen (Auswahl)
- “Design of Unequal Error Protection LDPC Codes for Higher Order Constellations”. IEEE International Conference on Communications (ICC 2007), Glasgow, Scottland, UK, June 24-28, 2007
N. von Deetzen and S. Sandberg
- “Unequal Error Protection Multilevel Codes and Hierarchical Modulation for Multimedia Transmission”. IEEE International Symposium on Information Theory 2008 (ISIT 2008), Toronto, Canada, July 6-11, 2008
N. von Deetzen and W. Henkel
- “Design of Bandwidth-Effcient Unequal Error Protection LDPC Codes”. IEEE Transactions on Communications, Vol. 58, No. 3, pp. 802-811, March 2010
S. Sandberg and N. von Deetzen
- “Leaking Interleavers for UEP Turbo Codes”. 6th International Symposium on Turbo Codes & Iterative Information Processing, Brest, France, September 6-10, 2010
A. Wakeel, D. Kronmueller, W. Henkel, H. Beltrão Neto
- “On the UEP Capabilities of Several LDPC Construction Algorithms”. IEEE Transactions on Communications, Vol. 58, No. 11, pp. 3041-3046, November 2010
N. von Deetzen and S. Sandberg
- “Relation between Global and Local EXIT Charts in Hybrid Turbo Codes”. 8th International ITG Conference on Source and Channel Coding, Siegen, Germany, January 18-21, 2010
H. Beltrão Neto and W. Henkel
- “UEP Concepts in Modulation and Coding”. Hindawi, Advances in Multimedia, Vol. 2010, Article ID 416797, 14 pages, 2010
W. Henkel, K. Hassan, N. von Deetzen, S. Sandberg, L. Sassatelli, and D. Declercq
(Siehe online unter https://dx.doi.org/10.1155/2010/416797) - “Multi-edge framework for unequal error protecting LT codes”. IEEE Information Theory Workshop, October 2011, Paraty, Brazil
H. V. Beltrão Neto, W. Henkel, and V. C. da Rocha Jr.
- “Multi-edge type unequal error protecting low-density parity-check codes”. IEEE Information Theory Workshop, October 2011, Paraty, Brazil
H. V. Beltrão Neto, W. Henkel, and V. C. da Rocha Jr.
