Multiplex communications – Duplex – Communication over free space
Reexamination Certificate
1997-12-17
2001-07-03
Hsu, Alpus H. (Department: 2738)
Multiplex communications
Duplex
Communication over free space
C359S199200, C359S199200, C375S222000, C379S056300
Reexamination Certificate
active
06256296
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to communication networks, and specifically to wireless communication networks based on infrared radiation.
BACKGROUND OF THE INVENTION
The Internet is the world's fastest developing mass media channel. Not only are increasing numbers of home computer users using the Internet, but most major television manufacturers are also developing or introducing Internet-connectable television sets. Since Internet connections are made primarily over telephone lines, any Internet-connectable device, whether a television or a conventional computer, must generally be placed in proximity to an existing telephone outlet, or telephone wires must be run to the location of the device.
Wireless computer communication devices and systems are known in the art. For example, cellular modems may be used without the need for telephone wires, but such modems are expensive both to purchase and to use. Elcom Technologies, of Canada, has recently announced the “EZONLINE” modem, which operates by modulating AC power lines, but this new technology is not yet widely used or available, nor is it really wireless, since it simply uses the AC lines in place of the telephone wires.
A number of industry standards have also been developed for wireless infrared (IR) computer communications, including ASK, IrDA 1.0/1.1 and new, emerging standards, such as an IR bus for control of computer peripherals. Existing IR wireless communications links generally operate at low speed, however, and carry only limited digital signals, rather than video and voice information. A clear line of sight (LOS) is generally required between the two ends of the link.
Computer local area networks (LANs) based on diffuse infrared transmission are also known in the art, for example, the ControLan System, produced by Moldat of Lod, Israel, and the AndroDat System produced by Androdat GmbH of Puchheim, Germany. Diffuse signals, in contrast to direct signals, are transmitted in all directions, and therefore can create a communication link with any receiver within a given radius of the transmitter. However, the above-mentioned diffuse IR systems require ceiling-mounted relay units, which need to be fixedly mounted and connected to a source of electrical power. Generally speaking, they are not suited for connection of a single computer or Internet-enabled television to a communication line in a home or small office.
SUMMARY OF THE INVENTION
It is an object of some aspects of the present invention to provide improved devices and systems for wireless computer communications.
It is another object of some aspects of the present invention to provide a wireless link between a television set and a computer network, such as the Internet.
It is a further object of some aspects of the present invention to provide a wireless control link between a television set or a computer and peripheral devices associated therewith.
It is still a further object of some aspects of the present invention to provide devices and systems for wireless telephone communications within a home or office.
It is an additional object of some aspects of the present invention to provide wireless communication devices and systems that do not require a clear line of sight between the communication devices.
In preferred embodiments of the present invention, a wireless IR communications link comprises a base unit and one or more remote units. The base and remote units communicate with one another by transmitting and receiving modulated, diffuse IR radiation. The base unit is connected to a wired communication line, such as a telephone line. Each of the remote units is preferably connected to a respective audiovisual device, such as a PC or a suitably-equipped television set, or to a peripheral device, such as a keyboard, associated with such an audiovisual device. The communications link allows the audiovisual device or devices to receive and send signals over the communications line, without any wired connection to the line. The peripheral device may be used to control and interact with the audiovisual device, similarly without the need for a wired connection therewith.
Unlike IR data links known in the art, the communications link of the present invention operates at high speed, preferably between 192 kbps and 2 Mbps, most preferably at least 1 Mbps, suitable for interactive multimedia transmission. The link may therefore be used to couple the audiovisual device to a network, such as the Internet, via the telephone line or other suitable data line, including ISDN and PTSN lines, as are known in the art. The link is also suitable for conveying voice communications.
Furthermore, because the link is based on transmission and reception of diffuse IR radiation, there need not be a clear line of sight between the base and remote units. The radiation transmitted by one of the units is received by the other unit after reflection (generally diffuse reflection) from one or more surfaces in a vicinity of the units. The link is preferably used in an enclosed, indoor area, in which the IR radiation is reflected from the walls and ceiling of the area. There is no need for IR relay units mounted on the ceiling or on other surfaces, as in diffuse IR systems known in the art, and no requirement for any special wiring or installation.
In some preferred embodiments of the present invention, the base unit is fixed to a telephone wall outlet, and one of the one or more remote units is fixed to a personal computer (PC) or an Internet-enabled television set. The communications link enables a user of the PC or television set to connect to a computer network, preferably the Internet, and to browse and view multimedia programs transmitted on the network.
Although in some preferred embodiments, only a single remote unit may be used, in other preferred embodiments of the present invention, the link connects the base unit with multiple remote units simultaneously. The base unit may communicate with the multiple remote units one at a time, in sequence, or over multiple, parallel channels. One of the units, preferably one of the remote units that is connected to a PC or Internet-enabled television, is assigned to serve as a master unit, which synchronizes and monitors transmissions from the other units. Preferably, each of the units transmits during a predetermined time slot, in accordance with a time-division multiple access (TDMA) scheme. In this manner, multiple units, preferably up to four units, but alternatively even greater numbers of units, can be linked simultaneously substantially without mutual interference.
Although preferred embodiments are described herein with reference to certain types of audiovisual devices and their connection primarily to telephone communication lines, it will be appreciated that the principles of the present invention may similarly be applied to produce wireless, diffuse IR communication links for other purposes. For example, such communications links may be used to connect a cordless telephone handset to a receiver, or to connect a portable Personal Digital Assistant (PDA) to a desktop computer, or to connect a digital camera to a PC or a printer. IR communication links in accordance with the principles of the present invention may carry either digital or analog data, and may operate in either half-duplex or full-duplex mode.
There is therefore provided, in accordance with a preferred embodiment of the present invention, a wireless communications link, including:
a base unit, which is connected to a wired communications line, so as to receive electrical signals from the line and transmit diffuse infrared radiation, modulated responsive to the received electrical signals, and to receive modulated infrared radiation and transmit electrical signals over the communications line responsive to the received infrared radiation; and
at least one remote unit, which is connected to an audiovisual device, and which couples the device to the communications line by receiving the modulated infrared radiation transmitted by the bas
Eder Haim
Ruziak Yaron
Amster Rothstein & Ebenstein
Hsu Alpus H.
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