Cebus Protocol-based Spread Spectrum Technology In Applied Research, Power Line Carrier Communication

Digital data transmission over the low voltage network has many advantages. Because transmission lines are already present, no new wire is needed. Furthermore, Any load attached to the power circuit can be reached through it. However, Power lines are not the best carrier. In order to implement reliable and robust power line communications, the obstacles of various noises jamming and attenuation must be removed. Spectrum spreading technique which shows high rejection to interference seems suitable for date transmission over power line. Therefore the purpose of this paper is to conduct research on applying spread spectrum technology on the data transmission over power line.After discussion the transmission channel property and noise of power lines, this paper pointed out that the obstacles fall into four categories: variable attenuation and impedance, impedance modulation, impulse noise, narrow-band frequency impairment. Aiming at solving this problem, this paper analyzed and compared all kinds of spread spectrum power-line carrier technologies, discussed the advantages and disadvantages of these technologies, and finally decided to adopt the method of Spread Spectrum Carrier (SSC).After theory analysis in depth, this paper discussed emphatically on the design details of the schemes. CEBus compatible power line carrier IC P300 was applied and a simple point -to-point power line communication system was implemented both in software and hardware. This system can realize half-duplex communication through power lines and obtain the statistics on reliability. The Spread Spectrum Carrier (SSC) technology put forward in the paper has being applied in the environment of laboratory and office building. The result proves that it is suitable for communications over lower voltage power lines, and the system can work well within certain distance.