Some Results on Physical-Layer Raptor Codes
Date Issued
2015
Date
2015
Author(s)
Wu, Hsuan-Kuan
Abstract
This thesis describes a study into coding and modulation techniques for incremental redundancy automatic repeat request (IR-HARQ) and high order modulation schemes designed to increase throughput over the AWGN channel. The research is based on two major classes in IR-HARQ: Raptor Codes and Punctured LDPC codes. In the first part of this thesis, an analysis of the conventional optimizing method is conducted for both schemes before presenting an efficient approach to combining systematic Raptor Codes and Punctured LDPC codes in order to construct a code that provides an improvement in SNR ranges lower than the specific optimized SNR compared with the same pre-code as conventional systematic Raptor Codes. In the second part, the linear programming in Raptor Codes is applied to the high order modulation. Adaptive degree distribution is used on Gray-mapped 4PAM and 8PAM modulation, which can be easily implemented on 16QAM and 64QAM modulation. The simulation shows the adaptive degree distribution is able to retain a high channel efficiency for wide SNR regions.
Subjects
Rateless codeing
Raptor code
Puncdured LDPC
Channel capacity
AWGN channel
EXIT analysis
Type
thesis