Power line data communication using timed transmission

This paper proposes a timed transmission method for data communication on in-building power conductors. The advantage of using such a system is that the network is easily re-configured and can be accessed through any wall socket without additional wiring cost to the user. Unfortunately, the AC power conductors present a hostile transmission environment for data signals. This is due to high noise levels, low impedance and severe attenuation, all of which change with time. To combat the effects of noise, other authors have used FSK together with spread spectrum and/or forward error correction. In contrast, this paper presents an interference avoidance scheme which recognizes that much of the channel noise appears to be cyclostationary. Transmission is suspended during periods of high interference (or noise) and then continues during quiet intervals. To demonstrate the effectiveness of this scheme, the paper presents noise and bit error rate (BER) measurements as a function of time