Patent Application
20080022324
The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references indicate similar elements.
The following description and drawings are illustrative of the invention and are not to be construed as limiting the invention. Numerous specific details are described to provide a thorough understanding of the present invention. However, in certain instances, well-known or conventional details are not described in order to avoid obscuring the description of the present invention. References to one or an embodiment in the present disclosure are not necessarily references to the same embodiment; and, such references mean at least one.
One embodiment of the invention provides a system which uses the existing television broadcasting band to transmit video content, via wirelessly radio frequency (RF) television (TV) signals, from consumer apparatuses such as a personal computer (PC), a set top box (STB), a game console, a portable video player, to television signal receivers such as a television set. The video content may be a television program or a multimedia stream.
In one embodiment, the system has a limited transmission power (e.g., a few miliwatts to less then a few Watts) for personal, home, or office use, without interference with existing television broadcasting systems. The personal area television signal broadcaster (111) is designed to be equipped with an antenna having a size in the order of a few inches for transmission. For example, a personal TV broadcasting system may be used for entertainment purpose in private homes, or for training or meeting in offices. Thus, video content can be broadcast in a personal area via existing or emerging television technologies and/or broadcasting bands to provide new services.
In this description, the term personal area is used to refer to a limit broadcasting area (e.g., having a range less then 100 meters, 20 meters, or even 10 meters), as oppose to a transitional wide area of broadcasting.
A conventional PC, STB, game console or video player is not capable of transmitting RF TV signals. One embodiment of the invention provides a RF TV transmitter in such devices for a personal area television broadcasting system.
In one embodiment, a transmitter of the system is integrated with a video source, such as a personal computer, a set top box, a game console, or a video player. Thus, a personal computer, a Set Top Box (STB), a game console or a portable video player can be used to transmit video content via RF TV signals.
Alternatively, the transmitter can be a device which is separate from the video source and which received input video signals via a cable (e.g., as a component video signal, a s-video signal, or a composite video signal). The transmitter includes a port for interfacing with such a cable to a video source.
In one embodiment, the RF TV transmitter uses the existing TV broadcasting band to transmit the television signals to avoid the need for additional frequency resource. In one embodiment, an unused channel is identified, automatically via a built-in receiver in the transmitter or manually. An unused channel can be identified when the signal level of detected existing broadcasting signals in that channel is lower than a threshold.
In one embodiment, to allow the receivers distinguish the RF TV signal of the transmitter from other signals detected in the same band, the strength of the RF TV signal is automatically tuned to be larger than that of other signals. In one embodiment, the strength of the RF signal is tunable to adjust the cover range of the personal TV system (e.g., to avoid delivering the content to neighbors, or to reduce the number of neighbors who can receive the transmitted RF TV signal).
The RF TV signal from the transmitter can be either analog or digital, and in compliance with the existing or future analog TV standards or digital TV standards. Thus, standard receivers, such as television receivers with a built-in TV signal tuner/demodulator, can be used to receive the TV signal.
For example, analog TV signals can be in accordance with a NTSC or PAL standard. Digital TV signals can be in accordance with a DVB-T, ATSC, TDS-OFDM, or DMB standard. Modulation parameters of the digital TV signal can be chosen accordingly.
Alternatively, the RF TV signals may be transmitted in a custom formats. Thus, corresponding custom receives can be used to receive the RF TV signals from such transmitters.
In one embodiment, a transmitter may add access control to the RF TV signal.
In one embodiment, a personal area television broadcasting system includes one or more features as described above. For example, a transmitter may include an access controller, a signal level controller, and/or a channel selector. Various combinations of the features describe herein can be implemented.
In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will be evident that various modifications may be made thereto without departing from the broader spirit and scope of the invention as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.
