The Wireless/Power-line Diversity Channel

Wireless devices are often connected to power outlets in residential data and smart-home networks. As a result, physical layer performance can be improved by using the power distribution tree as a diversity channel. This paper proposes a hardware-efficient, low intermediate-frequency (low-IF) transceiver architecture which allows existing wireless protocols to be used over both wireless and power-line communication (PLC) channels. A signal model for this form of hybrid transmission is presented assuming Rayleigh flat-fading and Middleton Class A impulsive noise in the wireless and PLC channels, respectively. Analysis of maximal-ratio combining (MRC) reveals that detector input noise is also Class A-distributed. Expressions for average bit-error rate (BER) of a BPSK subcarrier show that BER is a function of PLC impulsiveness and significant improvement can be achieved with diversity and PLC SNR > 10 dB. In regions of low and high wireless SNR, BER curves are approximately linear with slope of 0 and -1, respectively. The inflection point between these two regions can be used by transceivers to select between PLC-only and hybrid transmission modes.