Adaptive Bit-Loading and Channel Estimation with IMN For Plain Line and Line with Bridge Taps in Broadband PLC

The concept of transmitting VDSL2 broadband over power lines has gained substantial attention recently, particularly for its utility in distributing broadband within residential properties. Power lines and telephone lines exhibit distinct characteristics, such as differences in topology and load impedance. In this article, we employ the ABCD parameters of various sections to analyze the power line channel, specifically examining scenarios with up to 10 bridge taps over a 600-meter distance. We consider noise profiles that include periodic impulse noise, which is commonly observed in power line sections, as well as additive white Gaussian noise (AWGN). We also calculate the power spectral density (PSD) of impulse noise.Tone loading profiles are determined through the use of Discrete Multitone Transmission (DMT) in the context of VDSL2, with a bandwidth of 30 MHz. Our findings suggest that a lower Transmit Power Spectral Density (PSD) can be sufficient to achieve comparable data speeds to conventional VDSL2 technology, especially in the presence of bridge taps. However, in situations involving inductive loads in the bridge taps, which is common in residential settings, we propose a two-step strategy. Firstly, we recommend enhancing existing VDSL2 modem frontend hybrids by incorporating adjustable impedances that closely match the loaded line. Secondly, we suggest incorporating the ability to incrementally increase the Transmit Power Spectral Density (PSD) and add sub-bands to effectively achieve the desired data rates, similar to the seamless approach used in VDSL2.