Communications: electrical – Systems – Selsyn type
Reexamination Certificate
2000-07-11
2001-08-14
Lieu, Julie (Department: 2632)
Communications: electrical
Systems
Selsyn type
C340S315000, C340S315000, C340S315000, C340S315000, C340S870180, C340S870190, C340S870310
Reexamination Certificate
active
06275144
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to the field of power-line communication (PLC) transmission. This new communication transmission method will operate at transmission rates up to 1.6 gigabits per second capability.
The existing methods for transmitting data communication over the power-line uses various modulation techniques that manipulate a carrier(s) by phase, amplitude and/or frequency.
FIG. 1
illustrates a diagram of the conventional modulation techniques used in today's transmission technology.
Referring to
FIG. 1
, data
10
includes information that may be transmitted over the power line using one of the illustrated transmission techniques. Data
10
is represented by digital signals that are transmitted in strings of binary 1s and 0s. When amplitude modulation technique
20
is used to transmit data
10
, the data signal is blended into a carrier by varying the amplitude of the carrier. Specifically, the amplitude is modulated when it corresponds to a binary 0 of the data signal. On-off modulation technique
30
uses a transmitter which is turned off every time the transmitted data signal is represented by a binary 0. When frequency modulation using frequency shift keying (FSK) technique
40
is used, the data signal is blended into a carrier by modulating (shifting) the frequency of the carrier. The frequency shift occurs when a binary 0 in the data signal is encountered. Phase modulation using phase shift keying (PSK) technique
50
shifts the phase (e.g., 180°) when the data signal represented by a binary 0 is transmitted.
Using various modulation techniques, the power-line communication industry has obtained data rates of up to 10 megabits. Some of the above techniques use multiple carrier frequency such as DSS (Digital Spread Spectrum) or OFDM (Orthogonal Frequency Division Multiplexing). The use of spread spectrum and chirping signals used in transmission systems of today also limits the capacity. Using extended duration signaling techniques limits the theoretical transmission rate and rates faster than 40 megabits per second are not practical using such methods.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a power-line communications transmission system that can transmit information at extremely high rates with high quality of service (QoS). By using a differential voltage transmitting an offset low frequency sinusoidal signal, that uses an on-off keying (OOK) modulator at the rate of the data being transmitted, high bandwidth transmission speeds can be achieved. The On/Off state of the low frequency can be injected as an additive magnetic (Passive) element into the power-line alternating current or can be transmitted using an electro magnetically coupled injector (Active) into the magnetic field of the AC power. Using Active coupling, the transmitted information will require the power-line to be energized, however, using the Passive coupling method also allows for communication transmission with the power turned off. One advantage of this invention is that the system is dual coupled and transmits a transverse electromagnetic (T.E.M.) wave with an ultra-wide bandwidth. It is extremely important to be able to transmit reliable, high QoS information, in the home or office with or without the electrical power being on. When using this transmission technique for video, voice and data communications, the invention will provide the QoS required for each service provided. To provide telephone (voice) services to, from and within the home or office, the telephone must work for emergency services when power is out. This invention provides the ability to not only transmit and receive highspeed information, but to do so in any state that the electrical service is in. The transmission of information over power-lines within buildings or a campus environment and over the utility power grid is part of this invention. By modulating a low frequency, offset signal, using OOK differentially, information over the existing power-line infrastructure, speeds of up to 1.6 gigabits per second could be realized.
Another object of the present invention is to provide cable television-type service capabilities over the power-line. If a TV is equipped with this technology of the present invention, all you would need to do is plug the TV set into an AC power source and the TV network interface device will send out a signal to search for compatible devices on the power-line.
Another object of the present invention is to transmit high volumes of voice transmissions (telephone conversations) over power-lines and interconnect this transmission to the existing public telephone network system.
Another object is to use the power-line transmission technology to interface into the wireless transmission equipment environment. This will provide a wireless device, such as a gas meter monitor, to transmit and the power-line device to receive information that can be sent to a network operations center for billing, control and other services that are typical of services required by utility companies.
Another object of the invention is the ability for this technology to be channelized to provide isochronous, asynchronous, synchronous, and bisynchronous transmissions in a time division format. Video and voice would be isochronous and high-speed data transfers between computers would be asynchronous. All information will normally be sent serially.
Another object of the invention is the ability for video, voice and data to be intermixed in the power-line communication system. This will allow applying the invention to, for example, satellite, radio, cellular, microwave, PCS, telephone, audio, Internet & television communication, and to provide transmission from and reception by the corresponding devices over the powerline.
Another object of the invention is the ability to provide a network control hub that will synchronize and allocate the channels for the service requested. This network control hub would provide universal interfaces that would be plugged into the power-line and communicate to such other compatible devices as Microsoft Corporation's “UPnP” and Sun Microsystem's “JINI”
The present invention provides differential voltage offset frequency OOK as a transmission technology using a base frequency of 1000 hertz. This base frequency can be adjusted to take advantage of the best signal to noise ratio. This 1000-hertz frequency is turned to the ON position when a binary 1 (one) is sent from a computer and turned to the OFF position when a 0 (zero) is present. Using conventional Manchester encoding and decoding, all control and timing information can be transmitted within the serial bit stream, however, other coding can be used. The information/data from a digital source (PC, Computer, Audio System, VCR, etc.) is transmitted into a buffer and then sent to the OOK modulator. This modulator controls the ON and OFF states of the base frequency transmissions. Each ON state of the base frequency transmitted is then sent as a forward biased low frequency sine wave with enough current to drive the circuit for the duration of the ON symbol. The signal is then sent into a Passive or Active coupler to be connected to the power-line bus. Only one of the above two couplers is active and attached to the power-line at a time. The transmitted signal is then received at the far end and decoupled using the Active or Passive decoupling device. The signal is received having a resistive load and input into an optocoupler device to convert and isolate the circuit. The receiver senses current and converts the current to voltage. Once the current has been converted to voltage, the voltage is sent to a differential operational amplifier (Op Amp) circuit and the signal is then amplified. Using a Low Voltage Differential Signal receiver, the wave form is converted into a square wave that the receiving communication device can convert into a binary 1 (one) logic state. The transmission is detected as a differential current event using the transmission initial conditi
Blakely , Sokoloff, Taylor & Zafman LLP
Lieu Julie
TeleNetwork, Inc.
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