Pulse or digital communications – Systems using alternating or pulsating current – Plural channels for transmission of a single pulse train
Reexamination Certificate
2000-07-28
2004-07-06
Ghayour, Mohammad H. (Department: 2631)
Pulse or digital communications
Systems using alternating or pulsating current
Plural channels for transmission of a single pulse train
C375S220000
Reexamination Certificate
active
06760384
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
An object of the present information is a method for the distribution of binary information at high bit rates. It is aimed at using existing infrastructures to transmit information. The invention is more particularly useful in a small environment even if its use can be envisaged in a very big geographical area
2. Description of the Related Art
In the field of information transmission, the article by John M. Cioffi et al, “Very High Speed Digital Subscriber Lines” the IEEE Communications Magazine, April 1999, pp 72 to 79, lists all the techniques that can be used to transmit information at a high bit rate on a subscriber line consisting typically of a pair of copper wires, especially twisted copper wires. It is known that successive statements have been issued in this field, laying down the limits of transmissible bit rates and extending these limits each time. In practice, in these techniques, we distinguish between HDSL (High Speed Digital Subscriber Line) techniques that can be used with bit rates of the order of 100 Kbit per second over hundreds of kilometres, ADSL (Asymmetrical Digital Subscriber Line) techniques which are asymmetrical subscriber lines permitting bit rates of 1 to 2 Mbit per second over several kilometres, and VDSL (Very High Speed Digital Subscriber Line) techniques that allow bit rates of about 10 Mbit per second over very short distances, for example distances of 300 m.
Furthermore, especially in the field of home automation, there are known infrastructural problems related to the installation of high bit-rate connections in houses and office buildings. Indeed, the arrival of a coaxial cable head, a twisted pair, an optic fibre or a satellite port for television distribution opens the door to uses of the Internet through the access offered by the cable operator who has installed the cable. The drawback of this technique is that the coaxial cable thus brought in provides only one head, i.e. only one place of use. In home use, it may be useful to have a pending connector available at several points in a house for the connection, on demand, of a piece of equipment or making it possible, with this connection, to obtain a high bit rate accessible with a coaxial cable of this kind. A coaxial cable of this kind may furthermore be used on a multipoint basis by providing each end that is left unconnected with a circuit having a characteristic impedance. These circuits generally take the form of a plug that can be connected to a BNC type connector. This type of distribution is used especially in the field of office information technology systems for small local-area networks.
The drawback of this coaxial cable technique however is that the distribution of the access points through a dwelling or a building implies infrastructural works, cable passages and the making of connection outlets.
There are also possibilities of using a telephone line that comes into a subscriber's home. In this case two problems persist. Firstly, the distribution of the access points is not as general as users might wish even if, in modern dwellings, the presence of telephone sockets in each room of the dwelling is becoming a norm. However, this method of transmission suffers from the existing passband limits in the subscriber line concentrators used to connect several dwellings in an area of dwellings to a telephone exchange. In practice, the circuits of the concentrators have passbands that are below 100 KHz, thus making it possible to attain the high bit rates envisaged above, namely bits rates of the order of 10 Mbits per second.
OBJECTS AND SUMMARY OF THE INVENTION
To resolve this problem, the invention makes use chiefly of a technique of carrier currents. To set up a carrier current channel, it is necessary first of all that a sender unit or a receiver of signals to be transmitted should be coupled to an existing conductive line, generally the electrical power supply line of a building, or possibly on of the many telephone distribution lines subdivided into a tree structure in this building. A coupling of this type is known. It has the effect of isolating the sender unit and the receiver from the power signals distributed on the line which, in the present case, are of the order of 50 Hz for the electrical power supply or from the telephone signals whose frequency is below 30 KHz. At the same time, it has the effect of giving rise to an electrical decoupling in order to prevent the high voltage present on the line, an electrical supply voltage of about 220 Volts or 110 Volts, or an 80-volt pulse voltage in the case of a ringing sound conveyed by a telephone line, from disturbing the working of this sender unit and its receiver. Furthermore, a coupler of this kind couples the line in use, which may be the electrical power supply line or the existing telephone line, of the information to be transmitted or received.
In this case, the passband of this transmission is offset. In a preferred example of the invention, this passband will range from 150 KHz to a little more than 5 MHz. Indeed, beyond 5 or 6 MHz, the carrier current channel does not propagate the signals properly unless very complex solutions are contrived. In the invention, binary information elements at high bit rate are then received at a point of access to a global network, especially by a coaxial cable, an optical fibre, a twisted pair or the like, in a specialised receiver, for example a decoder provided by a cable operator. This binary information at high bit rate may be, firstly, television signals in the known passbands and, secondly, data signals resulting for example from an Internet connection on the part of the user and a transmission of the results of a request made by this user. The decoder or master device of the invention decodes the received signals and sends them to a user terminal, typically a microcomputer in the context of an Internet use, by means of a carrier current link. This network master device thus distributes the access to the total network, throughout the building, in carrier currents.
In this respect, an object of the invention is a method of distribution of binary information elements at high bit rate coming from a remote sender unit wherein:
a stream of information elements is received in a specialised receiver linked to the remote sender unit,
this stream of information elements is transmitted from the specialised receiver to a user terminal located in the vicinity, characterised in that:
the stream of information elements, after decoding in the specialised receiver, is retransmitted between the specialised receiver and the user terminal on a network, for example an electrical power supply network.
In another field, namely that of DMT or Discrete MultiTone mode modulation, there are known ways of transmitting information elements between a sender unit and a receiver by separating a wide passband, herein typically ranging from 150 KHz to more than 5 MHz in the example, into a large number of contiguous elementary frequency bands. In the example which will be taken hereinafter in the invention, a number of frequencies equal to 128 is chosen. The width for each of these frequencies is 39.0625 KHz giving a total bandwidth of 5 MHz. In this context, a specific problem appears because of a tree-structure network such as an electrical power supply mains network in a house. This specific problem is that of the numerous reflections to which the terminations of this network subject the signals that propagate therein. The channel thus constituted between two given points of this network is not very comfortable to use because it is the site of these reflections, also because it has a changing nature and finally because it is highly noise-ridden.
It is furthermore changing in nature because it is enough for the user to connect an electrical instrument to a current outlet or, quite simply, light up a lamp for the circuit of the distributed reflections to be overturned and cause other disturbances or different disturbances. Finally, a carrier curr
Fernandez Thierry
Garreau Dominique
Ghayour Mohammad H.
Kurtosis Ingenierie S.A.
Nguyen Dung X.
Patterson Thuente Skaar & Christensen P.A.
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