DSpace Collection:
https://hdl.handle.net/10171/41237
2024-03-28T23:13:38ZDesign of High Rate RCM-LDGM Codes
https://hdl.handle.net/10171/57276
Title: Design of High Rate RCM-LDGM Codes
Abstract: This master thesis is studies the design of High Rate RCM-LDGM codes and it is
divided in two parts:
In the rst part, it proposes an EXIT chart analysis and a Bit Error Rate
(BER) prediction procedure suitable for implementing high rate codes based on
the parallel concatenation of a Rate Compatible Modulation (RCM) code with a
Low Density Generator Matrix (LDGM) code. The decoder of a parallel RCMLDGM
code is based on the iterative Sum-Product algorithm which exchange
information between variable nodes (VN) and the corresponding two types of
check nodes: RCM-CN and LDGM-CN. To obtain good codes that achieve near
Shannon limit performance one is required to obtain BER versus SNR behaviors
for di erent families of possible code design parameters. For large input block
lengths, this could take large amount of simulation time. To overcome this
design drawback, the proposed EXIT-BER chart procedure predicts in a much
faster way this BER versus SNR behavior, and consequently speeds up their
design procedure.
In the second part, it studies two di erent strategies for transmitting sources
with memory. The rst strategy consists on exploiting the source statistics in
the decoding process by attaching the factor graph of the source to the RCMLDGM
one and running the Sum-Product Algorithm to the entire factor graph.
On the other hand, the second strategy uses the Burrows-Wheeler Transform to
convert the source with memory into several independent Discrete Memoryless
(DMS) binary Sources and encodes them separately.2019-01-01T00:00:00Z