Circular Trellis based Low Density Parity Check Codes
Irina Anitei · OhioLink ETD Center (Ohio Library and Information Network) · 2008
Tail biting circular trellis block codes (TBC) 2 used along with iterative Maximum A-Posteriori (MAP) decoders achieve performance very close to the Shannon limit.A Low Density Parity Check (LDPC) code using a Sum Product Algorithm (SPA) decoder is also known to achieve comparable performance.In this work the performance of (TBC) 2 encoder used with an SPA decoder is presented.The goal of this research is to compare the performance of (TBC) 2 encoder with different iterative decoders.In order to use the SPA for decoding, a parity check (H) matrix representation of the (TBC) 2 is developed.It is shown that for small block lengths this H matrix achieves comparable performance.For larger block sizes the H matrix representation of the (TBC) 2 encoder is found non-optimal for SPA decoding and the performance of the code is degraded.