Orthogonal Chirp-Division Multiplexing for Power Line Sensing via Time-Domain Reflectometry

In this study, a time-domain reflectometry (TDR) system based on the orthogonal chirp-division multiplexing (OCDM) scheme is proposed for power line sensing. After the system model description, a multiple access scheme that exploits the convolution theorem of the modified discrete Fresnel transform for enabling distributed reflectometric and transferometric power line sensing is introduced. Next, the effects of the parametrization of the proposed OCDM-based TDR system on range resolution and maximum unambiguous range are assessed. A comparison with multiple access schemes based on the Hermitian symmetric orthogonal frequency-division multiplexing (HS-OFDM) is then performed, being the number of measurements obtained over time and signal-to-interference-plus-noise ratio (SINR) used as performance metrics. Numerical results show that the proposed multiple access scheme achieves the highest number of measurements over time, besides yielding the same range resolution as the HS-OFDM-based counterparts. Finally, the proposed multiple access scheme is slightly outperformed by the HS-OFDM based on code-division multiple access and by the HS-OFDM based on frequency-division multiple access at some power line modems (PLMs) consisting the distributed sensing system, although its yielded SINR values at distinct PLMs are at a same level.