Broadcast signal retransmission system and method using illuminating visible-light communication

[0001] This application claims priority, pursuant to 35 USC 119, to that patent application entitled “Broadcast Signal Retransmission System And Method Using Illuminating Visible-Light Communication,” filed in the Korean Intellectual Property Office on Jan. 3, 2006 and assigned Serial No. 2006-0000345, the contents of which are incorporated herein by reference.

[0002] 1. Field of the Invention

[0003] The present invention relates generally to a broadcast signal retransmission system and method and, more particularly, to using illuminating visible-light communication system, wherein individual broadcast signals of available channels from a received multi-channel broadcast signal are transmitted using illuminating visible-light communication over power lines.

[0004] 2. Description of the Related Art

[0005] In recent years, radio communication systems have come into widespread use with the popularization of portable terminals. Owing to a shortage of available frequency resources, infrared communication systems using infrared rays, which have wavelengths shorter than those of radio waves, have been actively developed. However, in addition to the shortage of frequency resources, it has been confirmed that radio waves have detrimental influence on various medical or precision instruments. Infrared rays may also be detrimental to the human body in particular circumstances. In safety aspects of communication, visible-light communication systems attract much attention.

[0006] Development of blue light-emitting diodes (LEDs) has enabled realization of white LEDs. Compared with an incandescent lamp or fluorescent lamp, a white LED consumes much less power, is smaller, and has a longer lifetime. Research efforts are ongoing to transmit signals using white LEDs by controlling on/off operations or the light amount of the white LEDs.

[0007] Active research is taking place to integrate a signal transmission function of white LEDs with a power line communication (PLC) system. Such an integrated communication system utilizing visible light is not detrimental to the human body, enables safe communication, and is expected to provide worthwhile applications.

[0008] FIG. 1 is a block diagram showing a conventional broadcast signal retransmission system.

[0009] As shown in FIG. 1, the broadcast signal retransmission system comprises an information source 10, a power line modem 12, outlets 14 and 16 interconnected by a power line, an LED lighting fixture 20, and a light-receiving terminal 30.

[0010] The information source 10 is an information output apparatus providing various kinds of information, and may be a computer or a device composed of a tuner and receiver for television, cable television and radio broadcasting. Hence, broadcast information may be a video, audio, voice, still image, character data and others.

[0011] The power line modem 12 modulates information from the information source 10 and superimposes the modulated information on a power wave carried on the power line interconnecting the outlets 14 and 16 to transmit the modulated information through the power line. Although an ordinary PLC system includes a demodulating means to support two-way communication, the broadcast signal retransmission system is one-way and does not include a demodulating means. Frequency division multiplexing may be used for multiplexing information. The power line may be an indoor or outdoor electric power transmission line.

[0012] The LED lighting fixture 20 is connected to the power line, and illuminates the vicinity thereof. The LED lighting fixture 20 may be installed at the indoor ceiling of a house and may be used for various types of illumination including spot illumination.

[0013] The LED lighting fixture 20 includes an AC/DC converter 22, a band pass filter (BPF) 24, a coupler 26, and a plurality of LEDs 28. Because DC power is needed to drive the LEDs 28 to emit light, the AC/DC converter 22 converts AC power from the power line into DC power. The AC/DC converter 22 adjusts the voltage level of the DC power according to an operating voltage of the LEDs 28, and supplies operating power to the BPF 24.

[0014] The BPF 24 acts to extract an information signal superimposed on the power line, and may selectively extract a single information signal from multiple information signals.

[0015] The coupler 26 couples the information signal extracted by the BPF 24 to the wave of the DC power converted by the AC/DC converter 22. Hence, the level of the voltage fed to the LEDs 28 can be changed according to the information signal, thereby making it possible to control the amount of light of the LEDs 28 and an on/off operation thereof. For example, the power from the AC/DC converter 22 can be controlled by the information signal from the BPF 24 to turn on and off the LEDs 28.

[0016] The LEDs 28 are primarily light sources for illumination, and may be white LEDs or a combination of red, green and blue LEDs. The LEDs 28 are driven by the power from the coupler 26 to emit light. Because LED(s) 28 has a fast response time, the amount of light of LED(s) 28 or the on/off operation thereof can be controlled by an information signal, enabling transmission of the information signal in the form of light produced by the LED 28 or LEDs (e.g., combination of red, green and blue).

[0017] The light-receiving terminal 30 includes a light-receiving means to receive light emitted from the LED lighting fixture 20, and extracts an information signal from the received light and demodulates the extracted information signal to produce desired information. The light-receiving terminal 30 may be any appliance having a light-receiving means, such as a personal computer, portable terminal, mobile phone, audio instrument or television set.

[0018] However, in the conventional broadcast retransmission system, the broadcast signal transmitted through the power line from the information source 10 is a single channel signal; therefore identical information is distributed along available power lines. Consequently, users have no choice but to receive the same information retransmitted by the retransmission system through the light-receiving terminals 30. That is, a user cannot selectively receive a retransmitted broadcast signal of a desired channel according to the user's taste.

[0019] The present invention has been made in view of the above problems and provides additional advantages, by providing a broadcast signal retransmission system and method using illuminating visible-light communication, wherein two or more broadcast channel signals are selectively transmitted along different transmission paths.

[0020] Another aspect of the present invention is to provide a broadcast signal retransmission system and method using illuminating visible-light communication wherein a broadcast channel signal is selectively switched and transmitted to a desired location according to a user request.

[0021] In one embodiment, there is provided a broadcast signal retransmission system using illuminating visible-light communication, comprising at least one light-emitting diode (LED) lighting fixtures, which converts a broadcast channel signal received through a power line into a light signal and outputs the converted light signal as illumination light, at least one smart communicator, which performs a request message transmit operation for a desired channel, and decodes illumination light from a corresponding LED lighting fixture into a reply broadcast signal and outputs the reply broadcast signal and a home server for receiving a multi-channel broadcast signal, and for, upon reception of a channel signal request message containing a desired channel index and location reference from a particular smart communicator, setting a signal switching path on the basis of the location reference and transmitting a broadcast channel signal of the requested channel through a power line connected with the signal switching path to an LED lighting fixture installed at the site indicated by the location reference.

[0022] Preferably, the smart communicator comprises a short-range communication module for connecting to the home server to perform a signal request message transmit operation, a light-receiving section for receiving illumination light from a corresponding LED lighting fixture, a broadcast signal decoder for decoding the received illumination light into a reply broadcast signal and a user interface for outputting the decoded reply broadcast signal.

[0023] Preferably, the user interface includes at least one of a display section for displaying a video part of the decoded reply broadcast signal and an audio processor for outputting an audio part of the decoded reply broadcast signal.

[0024] Preferably, the smart communicator further comprises a key interface for inputting a channel signal request containing a location reference.

[0025] Preferably, the smart communicator further comprises a memory section for storing a reply broadcast signal transmitted from the home server and channel information of the reply broadcast signal.

[0026] The home server may comprise a communication module for signal request message reception from the smart communicators, a radio frequency (RF) coupler for outputting the received multi-channel broadcast signal to one or more output lines, one or more RF tuners, each of which tunes to a multi-channel broadcast signal from the RF coupler to detect a broadcast channel signal of an available channel according to an input command, at least one demodulator for demodulating the broadcast channel signals from the related RF tuners, a switching section for setting, according to the channel signal request message containing a desired channel index and location reference, a signal switching path to route a selected one of the broadcast channel signals demodulated by the demodulators and a power line modem for superimposing the selected broadcast channel signal routed along the signal switching path on a power wave carried on a power line to transmit the broadcast channel signal through the power line.

[0027] The home server may further comprise a channel information detector for detecting channel information from the demodulated broadcast channel signals, and a path controller for controlling a switching path setting operation of the switching section using the detected channel information.

[0028] In another embodiment, there is provided a broadcast signal retransmission method using illuminating visible-light communication, comprising the steps of: a) receiving a multi-channel broadcast signal, and demodulating the received multi-channel broadcast signal into broadcast channel signals by available channels, b) receiving a channel signal request message containing a desired channel index and location reference from a smart communicator, c) setting, according to the received channel signal request message, a signal switching path to route a selected one of the broadcast channel signals and d) superimposing the selected broadcast channel signal of the requested channel on a power wave carried on a power line connected to the signal switching path, and transmitting the broadcast channel signal through the power line to an LED lighting fixture installed at the site indicated by the location reference.

[0029] The broadcast signal retransmission method may further comprise the steps of: e) converting, on reception of the broadcast channel signal by the LED lighting fixture, the broadcast channel signal into illumination light and outputting the converted illumination light, and f) receiving, by the smart communicator, the outputted illumination light, and decoding the received illumination light into a reply broadcast signal to output the decoded reply broadcast signal.

[0030] The broadcast signal retransmission method may further comprise the step of: g) detecting channel information from the demodulated broadcast channel signals, and wherein, at the step c), the signal switching path is set through identifying the requested channel and detecting the broadcast channel signal of the requested channel, using the detected channel information.

[0031] Preferably, the step a) includes the steps of receiving the multi-channel broadcast signal to output the received multi-channel broadcast signal to one or more output lines, tuning to the multi-channel broadcast signal to detect the broadcast channel signals of the available channels, and demodulating the detected broadcast channel signals.

[0032] In a feature of the present invention, broadcast channel signals extracted from a received multi-channel broadcast signal can be routed along different signal paths. In response to a signal transfer request for a desired channel from a particular site, a selected broadcast channel signal is switched between the signal paths and transmitted via a power line leading to an LED lighting fixture installed at the particular site, and outputted through the LED lighting fixture. As a result, the user at a current location can selectively receive a desired broadcast channel signal through a nearby LED lighting fixture.

[0033] FIG. 1 is a block diagram showing a conventional broadcast signal retransmission system.

[0034] FIG. 2 is a block diagram showing a broadcast signal retransmission system using illuminating visible-light communication according to an embodiment of the present invention.

[0035] FIG. 3 is a block diagram showing the configuration of a home server in FIG. 2.

[0036] FIG. 4 is a block diagram showing the configuration of a smart communicator in FIG. 2.

[0037] FIG. 5 is a flow diagram showing a broadcast signal retransmission method using illuminating visible-light communication according to another embodiment of the present invention.

[0038] Hereinafter, embodiments of the present invention are described in detail with reference to the accompanying drawings. The same reference symbols identify the same or corresponding elements in the drawings. For the purposes of clarity and simplicity, some constructions or processes known in the art are not described to avoid obscuring the invention with unnecessary detail.

[0039] FIG. 2 shows the configuration of a broadcast signal retransmission system using illuminating visible-light communication according to an embodiment of the present invention.

[0040] As shown in FIG. 2, the broadcast signal retransmission system comprises a home server 100, a display device 400, one or more smart communicators 500 connectable for communication to the home server 100, and one or more LED lighting fixtures 700 installed at different locations.

[0041] The home server 100 controls operations of home-networked electronic appliances, and performs a required operation in response to a control command from a smart communicator 500. Additionally, in the present embodiment, the home server 100 receives a multi-channel broadcast signal via a receive antenna, detects broadcast channel signals of available channels in the received multi-channel broadcast signal using tuners, and decodes the detected broadcast channel signals. In the event of a channel signal request for a desired channel, the home server 100 transmits a selected one of the decoded broadcast channel signals through a power line to an LED lighting fixture 700 installed at a location indicated by the channel signal request. To this end, the home server 100 switches the selected broadcast channel signal between transmission paths, converts the format of the selected broadcast channel signal into a format transferable through power lines, and transmits the format-converted broadcast channel signal through a power line leading to a destination.

[0042] The display device 400 is connected to the home server 100, and represents a display appliance such as a television set to display a broadcast signal received by the home server 100.

[0043] The smart communicator 500 is an information appliance that can remotely control and monitor the home-networked electronic appliances through the home server 100 in real time and support not only voice and image communication but also portable Internet access. To this end, the smart communicator 500 includes a platform for supporting wireless broadband (WiBro), ZigBee, radio frequency identification (RFID) and global positioning system (GPS), and a user interface for controlling the home-networked electronic appliances. In the home, the smart communicator 500 controls the home server 100 through short-range communication utilizing, for example, infrared rays. From outside the home environment, the smart communicator 500 sends a control command, voice data and image data to the home server 100 through long-range Internet communication using, for example, WiBro over the communication network 50.

[0044] Additionally, in the present embodiment, the smart communicator 500 controls broadcast-signal reception of the home server 100, and broadcast-signal retransmission by demanding the home server 100 to transmit a desired broadcast channel signal to an LED lighting fixture 700 near to the smart communicator 500.

[0045] The LED lighting fixtures 700 are located at different sites. Each LED lighting fixture 700 receives a broadcast channel signal via an associated power line from the home server 100, converts the received broadcast channel signal into a light signal, and outputs the light signal.

[0046] Each smart communicator 500 further includes a light-receiving means for receiving light emitted from a nearby LED lighting fixture 700. The smart communicator 500 receives the emitted light, extracts a broadcast channel signal from the received light, and demodulates the extracted broadcast channel signal to output broadcast information of a requested channel.

[0047] To this end, the smart communicator 500 residing at a site (for example a first room, second room, kitchen or rest room) sends a channel signal request message containing a desired channel index and location reference to the home server 100 through short-range wireless communication. In return, the home server 100 switches the corresponding broadcast channel signal in the received multi-channel broadcast signal to a power line leading to the LED lighting fixture 700 installed at the site where the smart communicator 500 is currently present. The smart communicator 500 then receives a light signal emitted from the LED lighting fixture 700, extracts a broadcast channel signal from the received light signal, and demodulates the extracted broadcast signal to output desired information of the requested channel.

[0048] FIG. 3 is a block diagram showing a configuration of the home server 100 in FIG. 2.

[0049] As shown in FIG. 3, the home server 100 comprises a radio frequency (RF) coupler 105 for outputting a multi-channel broadcast signal received by an antenna to one or more output lines, one or more RF tuners 110 for tuning to the multi-channel broadcast signal from the RF coupler 105 to detect broadcast channel signals of available channels, one or more demodulators 120 for demodulating the extracted broadcast channel signals from the associated RF tuners 110, a switching section 140 for switching the demodulated broadcast channel signals between signal switching paths according to inputted commands, and a power line modem 150 for superimposing the broadcast channel signals on power waves carried on power lines to transmit the broadcast channel signals through the power lines.

[0050] The home server 100 further comprises a channel information detector 160 for detecting channel information of the demodulated broadcast channel signals from the demodulators 120, a channel information memory 170 for storing the detected channel information, a path controller 180 for controlling the switching section 140 to set the signal switching paths for routing the broadcast channel signals from the demodulators 120, a path information memory 185 for storing path information regarding the power lines leading from the home server 100 to the individual LED lighting fixtures 700, and a communication module 190 for connecting to the individual smart communicators 500 via the communication network 50 to perform communication operations.

[0051] Upon reception of a channel signal request message containing a desired channel index and location reference from a smart communicator 500, the path controller 180 selects a power-line path leading to the LED lighting fixture 700 indicated by the location reference from the path information stored in the path information memory 185, and controls the switching section 140 to route the requested broadcast channel signal to the LED lighting fixture 700 (see FIG. 2) through the selected power-line path. The requested broadcast channel signal is superimposed by the power line modem 150 on a power wave carried on a power line corresponding to the power-line path, and transmitted through the power line to the LED lighting fixture 700.

[0052] Although, in the present embodiment, broadcast channel signals are obtained using a combined structure of a single antenna receiving a multi-channel broadcast signal, the RF coupler 105 outputting the received multi-channel broadcast signal to multiple output lines, and the RF tuners 110 detecting individual broadcast signals of available channels, they may also be obtained using a combined structure of a plurality of antennas and a plurality of corresponding RF tuners.

[0053] FIG. 4 is a block diagram showing the configuration of a smart communicator 500 in FIG. 2.

[0054] As shown in FIG. 4, the smart communicator 500 comprises a controller 510, a short-range communication module 520, a long-range communication module 530, a key input section 540, a light-receiving section 550, a broadcast signal decoder 560, a display section 570, an audio processor 580, and a memory section 590.

[0055] The controller 510 controls the overall operation of the smart communicator 500. In the present embodiment, the controller 510 also controls the smart communicator 500 to connect to the home server 100 through the communication network 50 (see FIG. 2) for transmission of a channel signal request message containing a desired channel index and location reference of the smart communicator 500. In addition, the controller 510 controls regeneration of the requested broadcast channel signal from a light signal emitted by a corresponding LED lighting fixture 700 (see FIG. 2) indicated by the location reference.

[0056] The short-range communication module 520 provides a capability of short-range wireless communication using, for example, infrared rays to control the operation of the home server 100 in the home. In the present embodiment, the short-range communication module 520 transmits a channel signal request message containing a desired channel index and location reference of the smart communicator 500 to the home server 100.

[0057] Outside the home, the long-range communication module 530 provides a capability of a wireless Internet access to the home server 100 using, for example, the WiBro technology via the communication network 50.

[0058] The key input section 540 includes keys for inputting commands to control operations of the smart communicator 500 through the controller 510 and to remotely control operations of the home server 100 in or outside the home. In the present embodiment, the key input section 540 also includes keys for inputting a channel signal request containing a desired channel index and location reference of the smart communicator 500 to be transmitted to the home server 100.

[0059] The light-receiving section 550 receives a light signal from the corresponding LED lighting fixture 700.

[0060] The broadcast signal decoder 560 decodes the light signal received by the light-receiving section 550 into a broadcast channel signal. The display section 570 displays status information on operations of the smart communicator 500. In the present embodiment, the display section 570 also displays a video part of the decoded broadcast channel signal. For a voice communication capability of the smart communicator 500, under the control of the controller 510, the audio processor 580 converts an analog audio signal from a microphone MIC into a digital signal, and converts a digital audio signal from the controller 510 into an analog signal and outputs the analog signal through a speaker SPK. In the present embodiment, the audio processor 580 also outputs an audio part of the decoded broadcast channel signal.

[0061] The memory section 590 stores executable programs needed to operate the smart communicator 500, and may also store operation setting information of the home server 100. In the present embodiment, the memory section 590 also stores channel information 592 regarding broadcast channels available from the home server 100, and broadcast data 594 received from the home server 100.

[0062] FIG. 5 is a flow diagram showing a broadcast signal retransmission method using illuminating visible-light communication according to another embodiment of the present invention. As shown in FIG. 5, the method comprises the following steps.

[0063] Firstly, the RF coupler 105 of the home server 100 outputs a multi-channel broadcast signal received by the antenna to the individual RF tuners 110 in step S110.

[0064] According to an input command, the RF tuners 110 tune to the multi-channel broadcast signal from the RF coupler 105 to detect broadcast channel signals of available channels, and output the detected broadcast channel signals to the corresponding demodulators 120 in step S120.

[0065] Each of the demodulators 120 demodulates the broadcast channel signal outputted from the corresponding RF tuner 110, and outputs the demodulated broadcast channel signal in step S125. The channel information detector 160 detects channel information from the demodulated broadcast channel signals and stores the detected channel information in step S130.

[0066] In response to a user command, a smart communicator 500 sends a channel signal request message containing a desired channel index and location reference to the home server 100 in step S140. The path controller 180 of the home server 100 sets a signal switching path to route a broadcast channel signal of the requested channel based on the location reference in step S150.

[0067] To transmit the requested broadcast channel signal, the home server 100 superimposes, using the power line modem 150, the broadcast channel signal from the signal switching path on a power wave carried on a power line leading to the LED lighting fixture 700 installed at the site indicated by the location reference in step S160. The LED lighting fixture 700 outputs a light signal corresponding to the broadcast channel signal from the home server 100 in step S170.

[0068] The smart communicator 500 receives the light signal from the LED lighting fixture 700 in step S180, decodes the received light signal into a broadcast channel signal in step S190, and outputs the decoded broadcast channel signal as the requested broadcast channel signal in step S195.

[0069] Accordingly, when a user at a site in the home sends a channel signal request message to the home server 100, the home server 100 transmits a requested broadcast channel signal to the user. Therefore, the user can selectively receive a desired broadcast channel signal at any site in the home.

[0070] As apparent from the above description, the present invention provides a broadcast signal retransmission system and method wherein broadcast channel signals extracted from a received multi-channel broadcast signal can be routed along different signal paths so that, in reply to a channel signal request from a particular site, a selected broadcast channel signal is switched between the signal paths and transmitted via a power line leading to an LED lighting fixture installed at the particular site, and outputted through the LED lighting fixture. As a result, the user at a current location can selectively receive a desired broadcast channel signal through a nearby LED lighting fixture.

[0071] The present invention is disclosed in the preferred embodiments shown in this specification and in the accompanying drawings. This disclosure is not intended to limit the scope of the invention, but to serve only for illustrative purposes. It should be understood to the ordinary person skilled in the art that various changes or modifications of the embodiments are possible without departing from the spirit of the invention.