Channel Impulse Response Multilevel Quantization for Power Line Communications

Physical layer security (PLS) has become a popular topic in the research community as a complement to traditional security schemes. Particularly, by taking advantage of the channel's symmetry, a robust ecosystem of security applications has developed in wireless communications. However, in power line communications (PLC), the general lack of channel symmetry has limited and hampered the development of physical layer techniques. In this paper, we address the cited constraint, by deriving a symmetric virtual channel impulse response (CIR) from the corresponding asymmetric PLC channel state information (CSI). In view of this, we propose a low-complexity and, to the best of our knowledge, the first CIR multilevel quantization algorithm that can be used in various PLC applications. While we contextualize our solution within the PLS domain, it has a wide applicability. Specifically, we start by analyzing the PLC channel path delays reciprocity, its relationship with topology changes, and its independence from all other power line characteristics. Then, the quality and viability of the proposed scheme are quantified, by comparing the bit mismatch rate (BMR) with its one-level quantization counterpart. The simulation results, under different topologies, confirm the performance of the proposed approach that can reduce the BMR by at least three orders of magnitude with respect to the one-level quantization, for noise levels below 90 dBuV. Finally, we conclude the paper by showing a few applications of the proposed solution and highlighting some future research directions.