Pulse or digital communications – Spread spectrum – Frequency hopping
Reexamination Certificate
1999-11-23
2004-06-08
Chin, Stephen (Department: 2634)
Pulse or digital communications
Spread spectrum
Frequency hopping
C375S135000, C375S136000, C375S267000, C375S299000, C375S347000, C348S492000, C348S496000
Reexamination Certificate
active
06748005
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to improvements in remote video transfer for personal computers and other applications. More particularly, the invention relates to methods and apparatus highly suitable for providing a wireless interface for a handheld or portable unit to a remote personal computer.
BACKGROUND OF THE INVENTION
The personal computer (PC) has been one of the major technological innovations of the last several years. Initially, PCs were available only in a desktop configuration consisting of the following components: a separate display or monitor, such as a cathode ray tube, a separate enclosure for the processing electronics, various storage devices, such as hard disk, floppy disk and CD ROM, and a separate keyboard and mouse to enable user input to the PC.
In the desktop configuration, the PC components are typically arranged on a desk and are interconnected with cables to provide the electrical communication necessary for overall PC operation. Consumer demand for mobile PCs led to the development of laptop PCs in which a liquid crystal display (LCD), processing electronics, the keyboard, mouse and battery are integrated into a single, portable, compact enclosure. The requisite technology and integration underlying the successful commercialization of the laptop PC is such that the cost of the laptop PC greatly exceeds the cost of a comparably performing desktop PC. The consequences of such a cost differential are that the mobility and convenience offered by laptop PCs are typically enjoyed only by individuals whose businesses or employers require such mobility and can afford to pay the higher costs of a laptop compared to a desktop PC. The vast majority of home users, or consumers who use a PC within their homes for Internet access and for other PC applications, purchase desktop configured PCs.
Even for those home users who own and use a laptop PC, Internet access from any location within or outside of a home user's house typically requires connection to an Internet service provider through a standard landline telephone or cable, or a cellular telephone network. Both scenarios are undesirable to the home user for the following reasons. In the first scenario, it is highly unlikely that a landline telephone or cable port will be conveniently available at every location within and around the house from which the home user may wish to access the Internet. In the second scenario, the home user is forced to subscribe to cellular service, which is likely to result in substantial cellular “air time” costs during the time the user browses the Internet, as compared with a “free” local call.
Accordingly, it would be highly desirable and advantageous to provide a wireless, handheld, portable device for interfacing with a nearby personal computer, allowing low cost access to the Internet and other information services.
SUMMARY OF THE INVENTION
The present invention, working in conjunction with a desktop personal computer (PC) provides methods and apparatus to provide cost effective, portable and convenient access to the Internet and other PC applications from any location within a certain desired distance from the desktop. In one aspect, the present invention includes a compact handheld terminal which functions as a user interface device and communicates via a radio link with a base station which is located near and connected with a home user's desktop PC. The handheld terminal contains user interface components, such as a flat panel display, a pointing device, a stereo audio output connector, a microphone input connector and an optional keyboard. In addition, the handheld terminal contains a compact radio subsystem which receives appropriate video and stereo audio signals and transmits keyboard, mouse, radio channel probing and adaptive differential pulse-code modulation (ADPCM) encoded microphone signals. This subsystem includes a transmitter and a receiver, as well as an antenna. A microcontroller is also utilized to control the operation of the radio transmitter and receiver, in an advantageous frequency hopping arrangement referred to as “direct frequency modulation (FM) frequency-hopping” or “FM frequency-hopping”.
The display of the handheld terminal may suitably be any compact flat panel display capable of displaying video signals. The audio output of the handheld terminal provides stereo audio signals for earphones that may be worn by the user, ensuring both high quality audio and privacy when using the handheld terminal in locations where other people are present. The handheld terminal may suitably have similar dimensions and the form factor of a typical laptop PC, except that it is of lighter weight since it will typically not have many of the additional components of a laptop, such as hard disk drives and floppy drives.
According to one aspect of the present invention, the base station is connected through cables to keyboard, mouse, audio input, audio output and video ports of the desktop PC. The base station contains suitable electronic circuitry to allow radio transmission of video graphics adapter (VGA) video and stereo audio from the desktop's VGA and audio cards to the handheld terminal using the direct FM frequency-hopping approach, thereby ensuring high quality video, audio and privacy. The base station also includes a radio receiver for receiving and demodulating keyboard, mouse, radio channel probing and microphone signals transmitted from the handheld terminal and a decoder to decode the encoded microphone signals. A microcontroller is also utilized in the base station to control the operation of the radio transmitter and receiver.
According to one aspect of the present invention, the handheld terminal serves as a portable multimedia user interface device with capabilities and features which include a video display consisting of an integral flat LCD panel, voice input with an external or internal microphone, audio output with a stereo listening device, pointing device for on screen object selection and command, an alphanumeric input device such as a keyboard, access to all the features available at the PC, and a wireless interface with the base station.
The handheld terminal of the present invention enables home users to conveniently and remotely interface with their desktop PC while maintaining the convenience and portability typical of the use of a laptop PC. The remote wireless interface is enabled by the radio link between the handheld terminal and base station which carries the appropriate video, audio, keyboard and mouse signals between the desktop PC and the handheld terminal. The rugged, lightweight handheld terminal may be easily carried around by the user and, if desired, may be left in any convenient location such as on a night table next to the home user's bed or in the recreation room.
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Riazi Habib
Zuniga Michael Anthony
Chin Stephen
Lucent Technologies - Inc.
Lugo David B.
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