Performance analysis of powerline communication systems using OFDM with coding and diversity techniques

Abstract

Power Lines have been attracting research interests for promising applications as an infrastructure for data communications at a speed comparable to a local area network for the last few decades. Due to the inherent limitations of a power line, data speed is limited to certain kilo-bit per second. The limitations include the effect of non-white power line noise, power line impulsive noise, fading in a power line due to multiple reflections, receiver Gaussian noise, crosstalk due to the coupling of power line conductors and power line attenuation which has a non-flat frequency response characteristic. Significant amount of research works are reported during the last few decades to overcome the limitations. In this dissertation, analytical investigations are carried out on single input single output (SISO) and multiple input multiple output (MIMO) power line communication (PLC) systems to develop analytical approaches for evaluating the bit error rate (BER) performance of PLC systems taking into considerations the limitations imposed by the PLC channel. Primarily the investigations are carried out to evaluate the impact of power line background noise and impulsive noise on the BER performance of a SISO PLC system with a single power line conductor as the transmission line and a single receiver. Orthogonal FDM (OFDM) with binary PSK modulation is considered to carry out the analysis. Diversity in reception by using multiple receiver ports is analyzed to find the BER performance and improvement in receiver sensitivity. Further, several analytical models are proposed to quantify the effect of impulsive noise in a PLC which are based on Middleton’s impulsive noise models. Analytical developments are carried out carried out to find the performance results considering the various impulsive noise models in presence of non-flat Gaussian noise of powerline. Presence of a transformer in a power line deteriorates the performance of a PLC system. Analytical model for a PLC system with a transformer is also developed taking into account the transfer function of the transformer and is used to find the effect of transformer on the BER performance results. Performance results are evaluated without and with receiver diversity in presence of impulsive and non-flat Gaussian noise. Further, investigations are carried out to find an appropriate analytical model to evaluate the effect of multipath fading in a power line communication network in presence in different channel noise components. Performance results without and with receiver diversity in presence of power line fading are evaluated numerically for different system and channel parameters. Power penalty suffered by the system due to fading are also determined at a BER of 10-6. Analytical models are also developed for a MIMO PLC system to evaluate the effect of coupling between conductors of a three phase powerline. Space time block coding (STBC) and space frequency block coding (SFBC) are applied to a MIMO PLC system and analyses are developed to find the BER performance results. The improvement due to diversity in overcoming the limitations imposed by above mentioned channel effects are numerically evaluated. The dissertation provides novel analytical developments for determining the performance of a power line communication with SISO and MIMO configurations with appropriate models for power line non-flat Gaussian noise, impulsive noise, fading, crosstalk due to coupling among the conductors and the transformer effect. The findings of this dissertation will be useful for modeling the power line communication system with application of state of art coding, modulation and diversity techniques in a power communication system which may be a potential candidate for future broadband multimedia communication services.