Estratégias de codificação de canal para enlaces de transmissão óptica.

Abstract

This dissertation presents a study on the application of low-density parity-check codes (LDPC) to optical superchannels operating at very high transmission rates. In order to contextualize the focus of the work, the first four chapters contain tutorial reviews about dense wavelength division multiplexing (DWDM) optical networks, aspects of the physical layer for DWDM networks, and LDPC. This class of codes, known to deliver excellent performance when applied in a variety of communication channels, is based on sparse parity checking matrices. When compared to other coding schemes, LDPC result in improved error correction capability along with a less complex decoding algorithm. A Matlab code to evaluate the bit error rate (BER) performance for optical superchannels has been developed. Results recently published have been used to validate this code. A hypothetical 11 node optical network has been conceived to serve as a virtual testbed for the Matlab code. Several BER versus bit energy per noise energy curves have been obtained for specific optical transmission links. By applying LDPC, a coding gain of 8 dB at BER = 10−15 has been achieved for one of the simulated links.