Narrowband OFDM power line communication challenges, standardization, and semiconductor's role

In this paper, we focus on narrowband (NB) OFDM PLC standards and associated implementations operating in frequency bands below 500 kHz. With the emergence of the Smart Grid Automated Meter Infrastructure (AMI), an international PLC standards gap was identified requiring new technology to serve market needs for higher bitrates and increased robustness [1]. This paper provides a brief history of PLC technology alternatives and the emergence of NB OFDM PLC solutions that fill this “standards gap”. We discuss power line channel impairments (e.g., noise, impedance) that we have measured on power grids and in dwellings such as in high rise buildings [2]. These studies have influenced emerging international NB OFDM PLC standards [3][4] and existing NB OFDM PLC solutions[5][6]. An important topic beyond NB PLC standardization is defining how the new modems coexist with legacy PLC modems operating in the same frequency band. SGIP PAP-15 [6] has done considerable work coordinating PLC coexistence requirements with IEEE P1901.2, ITU-T G.990x standards development; and PRIME and G3-PLC Alliances. Semiconductor's role is then to provide a hardware and software platform to realize a robust communications solution that can be deployed around the world. So then another important topic addressed is computational complexity. We roughly estimate modem computations as a function of signal bandwidth. This analysis shows that NB OFDM PLC standards can be implemented in software using a simple microprocessor; and in addition the same hardware platform can be used to implement the various standards.