Comunicação cooperativa e em diversidade para power line communication

Abstract

This thesis aims at investigating and analyzing cooperative communication as well as communication with diversity to improve the coverage and the performance of power line communication (PLC) systems in outdoor and low-voltage distribution electric grids. In this context, the performance of cooperative protocols, such as amplify and forward (AF); amplify, equalize, and forward (AEF); and decode and forward (DF), are analyzed when only one relay, between the source node and destination node, is considered. The orthogonal frequency division multiplexing (OFDM) and single carrier with cyclic prefix (SC-CP) schemes; 4-QAM coherent modulation; linear and time invariant PLC channels, additive noise modeled as additive white Gaussian noise (AWGN) and additive impulsive Gaussian noise (AIGN) constitute the end-to-end communication link for performance evaluation. The performance results show that cooperation can offer benefits to PLC systems and, as a consequence, its introduction in new generations of PLC transceivers could be beneficial. Additionally, by taking into account the OFDM scheme, 4-QAM coherent modulation and the same constraints applied to analyze the cooperative communication, the communication with diversity, in which a subcarrier selection criterion is adopted, was also investigated and analyzed. The purpose of addressing diversity is to highlight what kind of gains can be obtained to improve the reliability and robustness of PLC transceivers, in order to fulfill the requirements of smart grid communication, such as smart metering. The numerical results verify that diversity can indeed increase the reliability and robustness of PLC transceivers, however it reduces the throughput. For smart metering, communication with diversity seems to be promising because reliability and robustness are much more important requirement than higher throughput.