Development of the ubiquitous network by the cable and radio fusion type high-speed power-line communication

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Research and development of ubiquitous networks have been done energetically. As the communication method, power-line communication (PLC) was used in this research. Although the conventional PLC transmitters inject signals between 100V lines, called the normal-mode injection, the proposed transmitters inject signals between a 100V line and the earth, called the phantom-mode injection. By using these two injection methods, the twice improvement of the channel capacity is aimed.Since the power-line cable has been designed for energy transmission, the injected signals with high spectrum components cannot be sealed in the cable, but the signals are emitted though feeble to space. Then the cable works as a kind of an antenna. If many lines are wired in a closed space like the interior of a room, a weak electric-magnetic field will be filled, so that radio communications can be realized. The communication performed in such a situation is called "a cable and radio fusion type PLC". It is the purpose of this research to realize the residential ubiquitous network about 100Mbps by PLC.Phantom-mode currents mainly contribute to the electromagnetic field radiation from power lines. Even if the injected mode was normal, the mode would be partly converted to the phantom mode depending on the degree of en electrical unbalance of the power-lines. Therefore it is very important to realize an accurate measurement of the degree of en electrical unbalance. The measured unbalance can affect the channel modeling.A probe for measuring LCL (Longitudinal Conversion Loss) which is the measure of the unbalance was developed in 2003. The channel modeling technique containing the degree of balance was examined in 2004, and it showed the validity experimentally using the above-mentioned LCL probe. By using this probe, the injection/extraction method of the phantom-mode signal could realize easily.