Efficient Decoding Algorithms for Low-Density Parity-Check Codes
Independent thesis Basic level (professional degree)Student thesisAlternative title
Effektiva avkodningsalgoritmer för low density parity check-koder (Swedish)
Low-density parity-check codes have recently received much attention because of their excellent performance and the availability of a simple iterative decoder. The decoder, however, requires large amounts of memory, which causes problems with memory consumption.
We investigate a new decoding scheme for low density parity check codes to address this problem. The basic idea is to define a reliability measure and a threshold, and stop updating the messages for a bit whenever its reliability is higher than the threshold. We also consider some modifications to this scheme, including a dynamic threshold more suitable for codes with cycles, and a scheme with soft thresholds which allow the possibility of removing a decision which have proved wrong.
By exploiting the bits different rates of convergence we are able to achieve an efficiency of up to 50% at a bit error rate of less than 10^-5. The efficiency should roughly correspond to the power consumption of a hardware implementation of the algorithm.
Place, publisher, year, edition, pages
Institutionen för systemteknik , 2005.
Electronics, LDPC, Low Density Parity Check, Tanner graph, decoding, sum-product, probability propagation, early decision, threshold
Other Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:liu:diva-2794ISRN: LITH-ISY-EX--05/3691--SEOAI: oai:DiVA.org:liu-2794DiVA: diva2:20136