WO2006136981A2

WO2006136981A2 - Apparatus and method for relaying broadcast singals

Info

Publication number: WO2006136981A2
Application number: PCT/IB2006/051917
Authority: WO
Inventors: Rob James Davies; Kairaz Contractor
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2005-06-21
Filing date: 2006-06-15
Publication date: 2006-12-28
Also published as: WO2006136981A3

Abstract

The present invention provides a method / an apparatus for relaying broadcast signals to a broadcast receiver. The apparatus comprises receiving means for receiving the broadcast signals, a steerable antenna for receiving location signals related to the location of the broadcast receiver, locating means for locating the direction of the broadcast receiver, and controlling means for controlling the steerable antenna to transmit the broadcast signals in the direction of the broadcast receiver. In this way, the relayed broadcast signals could become more concentrated, and its attenuation and interference could be reduced, especially for digital signal due to its strong directionality, thus the signal quality received by the broadcast receiver could be improved significantly.

Description

APPARATUS AND METHOD FOR RELAYING BROADCAST SINGALS

FIELD OF THE INVENTION

This invention relates generally to the technology of receiving broadcast signals, and more particularly to apparatus/method for relaying broadcast signals.

BACKGROUND OF THE INVENTION

The advent of digitally transmitted terrestrial television systems present exciting opportunities for consumer electronics manufacturers and their suppliers. Broadcasters in some countries (such as UK) already offer digital services in parallel with existing analogue offerings and there is much pressure, political and commercial, to switch over completely towards digital transmission within the next decade or so. The potential market for replacement or conversion (set-top box) receivers is likely to be huge and new applications will only serve to increase demand.

A possible spoiler is weak reception within buildings, including residential homes. In Europe, where DVB-T is widely deployed, existing analogue terrestrial networks were planned for roof-top reception and indoor reception is often unreliable and sometimes impossible. The situation looks to be similar for DVB-T transmissions, particularly during the transition period during which they have to co-exist with analogue transmissions without causing degradation of analogue reception. Increasing the transmission power might resolve many problems but is likely to be impracticable for many years.

Various proposals exist that implement the concept of a relay apparatus to improve the reception quality of broadcast signals within building. US patent application US

2004/0237117 Al (Filing Date: Dec. 30 2003, Inventor: Sung-IK Park, et al. ) discloses some of the various proposals, which is incorporated herein by reference.

Fig. 1 illustrates a simple version of a conventional relay apparatus for relaying DVB-T (Digital Video Broadcast Terrestrial) signals within a house. The roof-top reception antenna 110 receives RF (radio frequency) broadcast signal from a main transmitter (not shown), the filter 120 filters the received RF broadcast signal to let the RF signals only at a desired signal band pass through, the amplifier 130 amplifies the filtered RF signals and the transmission antenna 140 transmits the amplified RF signals within the house.

The advent of portable receivers (such as reliable TV receiver) makes the disadvantage of the current relay apparatus obvious. The relayed RF signals normally need to cover all areas of the house including kitchen and garden. But due to the intervening structure of the house, the attenuation is significant. One simple way to reduce the attenuation is to increase the transmission power of the relay apparatus, but by doing this the relayed RF signals may go far beyond the house and intervene with the relayed RF signals of the neighbors.

Therefore, there is a need to provide a new relay apparatus/method for relaying broadcast signals that could provide better signal quality for the portable broadcast receiver.

OBJECT AND SUMMARY OF THE INVENTION

It is an object of the invention to provide a new relay apparatus/method for relaying broadcast signals that could provide better signal quality for the portable broadcast receiver.

The object is achieved in an apparatus for relaying broadcast signals to a broadcast receiver. The apparatus comprises receiving means for receiving the broadcast signals, a steerable antenna for receiving location signals related to the location of the broadcast receiver, locating means for locating the direction of the broadcast receiver, and controlling means for controlling the steerable antenna to transmit the broadcast signals in the direction of the broadcast receiver.

According to one embodiment of the invention, the steerable antenna sends searching signals for searching for the broadcast receiver, and the location signals are response signals of the searching signals.

According to another embodiment of the invention, the location signals are leakage signals from a local oscillator of the broadcast receiver.

According to still another embodiment of the invention, the location signals carry the radio frequency channel information, the relay apparatus further comprises filtering means for filtering the broadcast signals, whereby the filtered broadcast signals only carry the information concerning the selected radio frequency channel, and the steerable antenna transmits the filtered broadcast signal in the direction of the broadcast receiver.

The object is also achieved in a method for relaying broadcast signals to a broadcast receiver. The method comprises the steps of receiving the broadcast signals, receiving location signals related to the location of the broadcast receiver, locating the direction of the broadcast receiver, and transmitting the broadcast signals in the direction of the broadcast receiver.

It is another object of the invention to provide a new apparatus for locating a broadcast receiver so that the relay apparatus could transmit broadcast signals in the direction of the broadcast receiver.

The object is achieved in an apparatus for locating a broadcast receiver. The apparatus comprises detecting means for detecting whether the broadcast receiver is on, and transmitting means for transmitting radio frequency signal indicating that the broadcast receiver is on.

According to one embodiment of the invention, the locating apparatus further comprises obtaining means for obtaining radio frequency channel selection information of the broadcast receiver, and the radio frequency signal carry the radio frequency channel selection information.

By using such a mechanism of locating the direction of a broadcast receiver and relaying broadcast signals in the said direction, the relayed broadcast signals could become more concentrated, and its attenuation and interference could be reduced, especially for digital signal due to its strong directionality, thus the signal quality received by the broadcast receiver could be improved significantly.

In addition, the relay apparatus could change its relay direction along with the location change of a portable broadcast receiver. Therefore, there is no rigorous sitting requirements with which the user of the portable broadcast receiver must comply. Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in further detail, and by way of example, with reference to the accompanying drawings wherein:

Fig. 1 illustrates a simple version of a conventional relay apparatus,

FIG 2 is a schematic diagram of a relay apparatus according to one embodiment of the invention,

FIG 3 is a schematic diagram of a locating apparatus according to another embodiment of the invention, and

FIG 4 is a schematic diagram of a broadcast receiver with locating function according to still another embodiment of the invention.

Throughout the drawings, the same reference numerals indicate similar or corresponding features or functions.

DETAILED DESCRIPTION OF THE INVENTION

FIG 2 is a schematic diagram of a relay apparatus according to one embodiment of the invention.

Apparatus 200 for relaying broadcast signals to a broadcast receiver (not shown) includes an antenna 110, a steerable antenna 250, a locating unit 210 and a control unit 220. It further includes a filter 110 and an amplifier 130. The broadcast receiver is a portable digital television receiver. It could also a portable digital audio receiver.

Antenna 110 receives RF broadcast signal from a main transmitter (not shown). Antenna 110 is roof-mounted (or, possibly, mounted inside the roof space) of a house. The RF signals are characterized as being either a COFDM multiplex conformant with the DVB-T recommendations (ETSI EN 300744) in one or both of the frequency ranges 170- 230MHz and 470-860Mhz or a conventional analogue television signal conformant with the relevant ITU-R recommendation in the same frequency bands.

Filter 120 filters the received RF broadcast signal to let the RF signals only at a desired signal band (such as 470-860Mhz) pass through, the amplifier 130 amplifies the filtered RF signals.

Steerable antenna 250 receives RF location signals related to the location broadcast receiver. The RF location signals are directly originated from the broadcast receiver, for example, a component inside the broadcast receiver. The RF location signals could be leakage signals from a local oscillator of the broadcast receiver.

The RF location signals could also be indirectly originated from a device (not shown) coupled to the broadcast receiver or a wireless tag (not shown) attached on the broadcast receiver.

Locating unit 210 locates the direction of the broadcast receiver according to the RF location signals.

One example is to achieve the location purpose mechanically. The steerable antenna 250 is rotateable, the angle that the steerable antenna receives the stongest RF location signals is the direction of the broadcast receiver.

Another example is to achieve the location purpose electronically. The steerable attenna 250 is physically fixed, and it includes several simple antennas for example, dipoles) which are arranged as an array. By analyzing the relative phases of the received RF location signals, the direction of the broadcast receiver could be obtained.???

The control unit 220 controls the steerable antenna 140 to transmit the amplified RF broadcast signals in the direction of the broadcast receiver. One example is the control unit 220 mechanically adjusts the gesture of the steerable antenna 140 to face the direction of the broadcast receiver.

Another example is the control unit 220 electrically adjusts the steerable antenna 140, for instance, by beamforming technology.

In a beamforming system, radiated power can be concentrated into one or more beams whose direction can be altered in a continuous or switched manner. In this context, the 'location' of a target receiver is defined as the beam setting that provides the best quality signal to the target receiver.

One electronic beam-forming system is the phased array approach. Several simple antennas (for example, dipoles) are arranged as an array and fed with substantially the same signal. By arranging for the relative phases of the inputs to be altered, the net radiation pattern of the array can be shaped into, for example, various directional patterns.

Appropriate adjustment of the phases allows directional beams (and nulls) to be steered. Other electronic beam-forming arrangements are known to exist.

Although beamforming is assumed here, other adaptive antenna mechanisms are well known to those skilled in the art and may alternatively be deployed.

Apparatus 200 could pro-actively send searching signals via the steerable antenna 250 to search for any broadcast receivers within its coverage. The searching signals could carry the information indication the existence of apparatus 200. The searching signals could be a stimulus signal to get response signals from the broadcast receiver indicating the location of the broadcast receiver. Extensive prior art in this area will be found in the domain of radar transponders, which return the identity of the vessel they are being carried in when illuminated by a radar beam. Modern RF ID tags operate on similar principles and could form the basis of such a system.

It is understandable that the antenna 110 could be replaced by a DVB-C or DVB-S connector, thus the DVB-C or DVB-S signals could be relayed within the house. It is also understandable that filter 110 and amplifier 130 could be replaced by other arrangements of processing the broadcast signals.

Optionally, apparatus 200 could further include a channel selection filter 230 and/or an equalizer 240. Under this circumstance, the filter RF broadcast signals will not go directly to the amplifier 130, but via the channel selection filter 230 and/or the equalizer 240.

The RF location signals may carry the RF channel selection information indicating the broadcast receiver is tuned to, for example, Leakage signals from a local oscillator of the broadcast receiver. The locating unit 210 could extract the RF channel selection information (for example, RF channel 21, 470-478Mhz) from the RF location signals, the channel selection filter 230 further filters the filtered RF broadcast signals (470-860Mhz) to only let the broadcast signals at 470-478Mhz pass through.

Equaliser 240 is arranged and dynamically adjusted to cancel any interference resulting from local feedback. The DVB-T signal itself provides the necessary synchronisation words to enable this and the ability to actively remove the local signal will provide some extra transmission headroom.

FIG 3 is a schematic diagram of a locating apparatus according to another embodiment of the invention.

Apparatus 300 includes a detecting unit 310 and a transmitting unit 320. it further includes a obtaining unit 330.

Apparatus 300 is a separate device coupled to the broadcast receiver, and could be sold together with apparatus 200 and placed in the proximity of the broadcast receiver (for example, on the top of the broadcast receiver).

Detecting unit 310 detects whether the broadcast receiver is on. Some approaches could be arranged that at least the power status of the broadcast receiver is known and can be communicated to apparatus 200, either continuously or in response to a stimulus signal. Power is sometimes available via a 12v outlet. Video outputs are often available via phono, SCART or other connectors. Detecting unit 310 could be developed to exploit these signals.

Transmitting unit 320 includes an antenna 340. When the detecting unit 310 finds the broadcast receiver is on, transmitting unit 320 transmits RF location signals via antenna 340 at a very specific frequency to apparatus 200. The specific frequency would ideally be a frequency immediately adjacent to or within the broadcast band so that the antenna's directional properties are similar for the pilot location signal and the DTV signals. In Europe, the 433 MHz or 868 MHz bands are possible, both lying just outside the UHF TV band. Other bands, for example, the 2.4 GHz ISM band, are possible (with some consideration to the antenna's directional properties) and may facilitate the use of standards such as ZigBee.

The RF location signals indicate the existence of the broadcast receiver. It may carry some information, such as the information indicating the broadcast receiver is a TV set.

Obtaining unit 330 obtains the RF channel selection information of the broadcast receiver. The UHF and VHF TV band are divided into 40-50 RF channels, and each RF channel corresponds to 3-4 program channels. When a user select one program channel, for example, BBC, The corresponding RF channel could be RF channel 21 (470-478Mhz).

The RF channel selection information could be communicated to apparatus 300 from the broadcast receiver via SCART or other connectors. The broadcast receiver's firmware can be updated (DTV receivers can typically be updated over-the-air) so that this SCART data channel can be used to provide data to apparatus 300.

FIG 4 is a schematic diagram of a broadcast receiver with locating function according to still another embodiment of the invention. Apparatus 400 is a portable broadcast receiver.

Like a conventional broadcast receiver, apparatus 400 includes an antenna 450, a digital RF signal processing unit 410, a control processor 430, a power circuitry 420 and a user input unit 440. Digital broadcast signals received by antenna 450 are processed by digital RF signal processing unit 410 under the control of control processor 430, then are sent for display.

The digital RF signal processing unit 410 includes a RF tuner 412, a demodulator 416 and a baseband processor 418. The RF tuner 412 includes a local oscillator 413. The leakage signals of the local oscillator could be detected by apparatus 200 so that apparatus 200 could know the direction of apparatus 400.

Apparatus further includes a detecting unit 310 and a transmitting unit 320. It could still further include an obtaining unit 330. The transmitting unit 320 includes an antenna 340.

When apparatus 400 is power on, the power circuitry provides power to all the components of apparatus 400. The detecting unit 310 automatically knows the power status of apparatus 400. Then the transmitting unit 320 transmits RF location signals at a very specific frequency to apparatus 200.

The RF location signals indicate the power circuitry is power on, which also mean that the broadcast receiver exists and is power on. It may carry some information, such as the information indicating the broadcast receiver is a TV set.

The user input unit 440 receives user input, for example, program channel selection information (program channel BBC), then the control processor 430 finds the RF channel (RF channel 21, 470-478Mhz) corresponding to the program channel, and control the RF tuner 412 to the RF channel. At this time, the leakage signals of the local oscillator carry the RF channel information.

The obtaining unit 330 obtains the RF channel selection information from either control processor 430 or RF tuner 412. The RF location signals transmitted by transmitting unit 320 may also carry the RF channel selection information. It is understandable that antenna 340 and antenna 450 could be combined into one antenna.

Although the above embodiments refer to a portable broadcast receiver, the relay apparatus of this invention also could relay signals to a non-portable broadcast receiver.

And although the above embodiments describe a system oriented towards television systems, in particular, digital television systems. It will be apparent that the same principles can also be exploited for other digital/analogue broadcast radio systems, including, but not limited to: Sound FM broadcast, Digital Audio Broadcast (DAB), digital television systems including other terrestrial systems (e.g., ATSC) and cable systems and satellite broadcast systems.

While the invention has been described in conjunction with specific embodiments, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and scope of the appended claims.

Claims

1. An apparatus for relaying broadcast signals to a broadcast receiver, comprising: receiving means for receiving the broadcast signals, a steerable antenna for receiving location signals related to the location of the broadcast receiver, locating means for locating the direction of the broadcast receiver, and controlling means for controlling the steerable antenna to transmit the broadcast signals in the direction of the broadcast receiver.

2. The apparatus of claim 1, wherein the broadcast signals are digital radio broadcast signals, and the broadcast receiver is a digital radio receiver.

3. The apparatus of claim 1, the steerable antenna sends searching signals for searching for the broadcast receiver, wherein the location signals are response signals of the searching signals.

4. The apparatus of claim 1, the location signals are leakage signals from a local oscillator of the broadcast receiver.

5. The apparatus of claim 1, wherein the location signals carry the radio frequency channel information, further comprising filtering means for filtering the broadcast signals, whereby the filtered broadcast signals only carry the information concerning the selected radio frequency channel, wherein the steerable antenna transmits the filtered broadcast signal in the direction of the broadcast receiver.

6. The apparatus of claim 1, further comprising an equalizer for canceling interference resulting from local feedback.

7. A method for relaying broadcast signals to a broadcast receiver, comprising the steps of: receiving the broadcast signals, receiving location signals related to the location of the broadcast receiver, locating the direction of the broadcast receiver, and transmitting the broadcast signals in the direction of the broadcast receiver.

8. The method of claim 7, further comprising the step of sending searching signals for searching for the broadcast receiver, wherein the location signals are response signals of the searching signals.

9. The method of claim 7, the location signals are leakage signals from a local oscillator of the broadcast receiver.

10. The method of claim 7, wherein the location signals carry the radio frequency channel information, further comprising the step of filtering the broadcast signals, whereby the filtered broadcast signals only carry the information concerning the selected radio frequency channel, wherein the transmitting step comprising the step of transmitting the filtered broadcast signal in the direction of the broadcast receiver.

11. An apparatus for locating a broadcast receiver, comprising: detecting means for detecting whether the broadcast receiver is on, and transmitting means for transmitting radio frequency signal indicating that the broadcast receiver is on.

12. The apparatus of claim 11, further comprising obtaining means for obtaining radio frequency channel selection information of the broadcast receiver, wherein the radio frequency signal carry the radio frequency channel selection information.

13. The apparatus of claim 11, the transmitting means comprising an antenna.

14. A broadcast reciever, comprising: an antenna for receiving broadcast signals carrying program information , a power circuitry for providing power, a processing unit for processing the broadcast signals to present the program information, detecting means for detecting whether the power circuitry is on, and transmitting means for transmitting radio frequency signal indicating the power circuitry is on.

15. The broadcast receiver of claim 14, wherein the program information is multi-channel program information, further comprising: user input means for receiving program channel selection information, and obtaining means for obtaining radio frequency channel selection information corresponding to the program channel selection information, wherein the radio frequency signal carry the radio frequency channel selection information.