IMPROVED LEAST SQUARE CHANNEL ESTIMATION ALGORITHM FOR OFDM BASED COMMUNICATION OVER POWER LINES

摘要

As the low power electrical distribution network may be utilized for data transfer, it should be considered as a good candidate for "last mile solution". However, the power line medium strongly depends on its own characteristics (frequency selectivity, multi-path, and non-linearity) and on the environment (noise). The realization of a power line communication (PLC) system is performed with the coded Orthogonal Frequency Division Multiplexing (OFDM) modulation technique, because of its properties in adverse environment for signal transmission. To combat these harsh properties of power line medium (attenuation, phase errors and noise) and its impact on data transmission, improved Least Square (LS) channel estimation technique is typically used. The introduced channel estimation algorithm is based on the combination of comb- and block-type pilot sub-carrier arrangement, while the channel interpolation is done using linear and cubic spline interpolation. Further, the computer based simulation of PLC OFDM model is introduced and used to verify proposed channel estimation technique.