Hardware Implementation of Filtered OFDM for BB-PLC using Software Defined Radio

Abstract

Among several in-home communication systems, broadband over power line communication (BB-PLC) provides better connectivity at cheaper installation cost without disturbing the existing infrastructure. Conventional broadband systems, including BB-PLC, use the orthogonal frequency division modulation (OFDM) to combat the issue of frequency selective fading at the cost of extra bandwidth. However, it is proposed and shown that the spectral efficiency of the OFDM can be improved either by using filter bank multi-carrier (FBMC) or filtered OFDM (F-OFDM). In the former, all the sub-carriers of an OFDM symbol are filtered, however, in the latter, only the final OFDM symbol is filtered. Thus, it is a cost-effective solution to use the F-OFDM over the FBMC. This paper presents the hardware implementation of the F-OFDM for BB-PLC. Different prototype low-pass filters are used for comparative analysis, especially for the BB-PLC. The simulations are carried out in National Instruments' LabVIEW software and the hardware implementation of the transceiver is done on National Instruments' Software Defined Radio (SDR) set called USRP 2920. Polycab 1.5 SQ mm home wiring power cable is used as the communication channel in testing the BB-PLC system. From the power spectral density analysis, it is concluded that the F-OFDM has better spectral efficiency than the conventional OFDM. Further, it is observed that as the length of the filter increases the better spectral efficiency is achieved but at the cost of increased complexity.