Channel estimation based on frame control symbol re-encoding and re-mapping

This work focuses on channel estimation in power line communications (PLC) systems. Considering the IEEE Standard 1901-2010 frame structure, data-aided channel estimation is performed on the preamble sequence. However, resolution of the preamble symbols compared to the Frame Control (FC) symbol and payload symbols (256 vs. 2048 subcarriers) leads to interpolation errors that tend to increase in presence of narrow-band interference (NBI). This work addresses channel estimation in standard IEEE 1901-2010 by re-encoding and re-mapping the FC symbol. The main contribution on this paper is to show that re-estimation of only the noise power spectral density (PSD) (and not the channel frequency response (CFR)) significantly improves system performance by using FC symbol as a new reference. This conclusion provides a feasible implementation in practical systems because the proposed solution does not lead to delays nor additional computational costs. Gain obtained by this update compared to preamble based channel estimation is substantial and system behavior, especially in the presence of NBI, improves considerably. A PLC system according to the standard IEEE 1901-2010 is used to evaluate our proposal. System performance is tested on multipath channels and narrow-band noise.