Abstract:
A communications device includes: a light-emitting diode (LED) or LED array; an internet protocol (IP)-based radiofrequency (RF) wireless unit, configured to transmit and receive data over a RF wireless communications network; a visible light communication (VLC) unit, configured to drive the LED or LED array and modulate light generated by the LED or LED array with data; a control unit, connected to the IP-based RF wireless unit and the VLC unit, configured to facilitate communications between the VLC unit and IP-based RF wireless unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application claims the benefit of U.S. Provisional Patent Application No. 61/967,423, filed Mar. 18, 2014, which is incorporated by reference. 
     
    
     FIELD 
       [0002]    Embodiments of the invention relate to a multi-functional smart LED system architecture, and in particular, to a smart LED system having several integrated capabilities, including illumination, Internet Protocol (IP)-based radiofrequency (RF) connectivity and visible light communication (VLC). 
       BACKGROUND 
       [0003]    Light-emitting diodes (LEDs) represent an eco-friendly illumination technology which features high luminous efficiency, long lift time and high reliability. LEDs, which are growing in popularity due to increasing performance and decreasing costs, are often used for lighting, display and signage applications. 
         [0004]    In addition, the high response speed of LEDs makes them suitable for electronic modulation, allowing them to be used in visible light communication (VLC) applications. The modulation frequency for LEDs can be set high enough to achieve meaningful data rates and to greatly exceed the flicker fusion threshold of human beings, such that the LEDs&#39; basic illumination function is not affected by the modulation. Compared with traditional wireless radiofrequency (RF) communications, VLC is advantageous in terms of higher security, no RF radiation, wide available spectrum and transceiver simplicity. For example, for downlink communications, VLC is able to reach data rates at the Gb/s level, and, for indoor positioning, VLC is able to achieve accuracy at the sub-meter level. 
         [0005]    However, there are also drawbacks to conventional VLC systems. For example, conventional VLC systems lack an effective way to integrate a backhaul system for data delivery to the source of the VLC downlink. For VLC to be used in downlink communications, the data to be transmitted over visible light needs to be delivered to the illumination fixture. Given that the LEDs are always connected to the power line, power line communication (PLC) has been recognized as a potential mechanism for providing a backhaul system. However, PLC devices are expensive and would significantly increase the costs associated with such a LED VLC system. Further, in terms of performance, PLC devices are sensitive to the noise from power grids, resulting in potential drops in data rate and communication interruptions. There is also a limit on the quantity of PLC devices allowed within one power grid, which is another obstacle to deployment of a LED VLC system using PLC technology for a backhaul. 
         [0006]    Another drawback relating to VLC systems is that conventional VLC systems lack a mechanism for VLC receivers to request data or other services via an uplink connection. 
       SUMMARY 
       [0007]    Embodiments of the invention provide for a multi-functional, smart LED device for a variety of applications, including but not limited to solid-state lighting, display and signage applications. The LED device provides VLC capabilities integrated with IP-based RF wireless connectivity, and includes, for example, a VLC unit, an IP-based RF wireless unit, a control unit with a memory (e.g., a non-volatile memory), and a LED array. 
         [0008]    With respect to the VLC capabilities, light from LEDs of the LED array is modulated at a high frequency such that any flickering associated therewith is imperceptible to the human eye. The modulated signal can thus be captured and decoded by nearby VLC receivers without any degradation to the LEDs&#39; lighting functionality. 
         [0009]    The IP-based RF wireless connectivity provides a data backhaul and/or uplink for the VLC-based communications, and further allows the VLC-based communications to be utilized as a bridge to extend RF signal coverage for an RF wireless communications network. 
         [0010]    Thus, embodiments of the multi-functional, smart LED device discussed herein provide for VLC communications integrated with RF wireless connectivity, while at the same time providing for illumination for various applications (e.g., lighting, display, signage, etc.). Further, the synergy and meshed usage of LED-based VLC and IP-based RF wireless connectivity allows for additional advantages to be achieved, including but not limited to high power efficiency, high reliability and low costs (including overall system costs as well as installation costs). 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0011]    While the appended claims set forth the features of the present invention with particularity, the invention, together with its objects and advantages, may be best understood from the following detailed description taken in conjunction with the accompanying drawings of which: 
           [0012]      FIGS. 1A-1B  are schematic diagrams illustrating exemplary smart LED systems. 
           [0013]      FIG. 2  is a block diagram illustrating components of an exemplary smart LED device. 
           [0014]      FIGS. 3A-3B  are block diagrams illustrating data pathways in various contexts for the exemplary smart LED device depicted in  FIG. 2 . 
           [0015]      FIG. 4  is a block diagram illustrating components of another exemplary smart LED device. 
           [0016]      FIGS. 5A-5C  are block diagrams illustrating data pathways in various contexts for the exemplary smart LED device depicted in  FIG. 4 . 
           [0017]      FIGS. 6-8  are flowcharts illustrating operations performed by exemplary smart LED devices. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    Embodiments of the invention provide for a multi-functional, smart LED device for a variety of applications, including but not limited to solid-state lighting, display and signage applications. The LED device provides VLC capabilities integrated with IP-based RF wireless connectivity, and includes, for example, a VLC unit, an IP-based RF wireless unit, a control unit with a memory (e.g., a non-volatile memory), and a LED array. 
         [0019]    In an exemplary embodiment, information received via an IP-based RF wireless connectivity interface of the IP-based RF wireless unit is used to program, control and monitor the VLC unit (e.g., including setting the operating frequency of the VLC unit, setting the light intensity of the VLC unit, and determining/transmitting the operating status of VLC unit). Communications between the VLC unit of a device with the VLC of another device are used to extend signal coverage of the RF wireless communications network (i.e., allowing the devices to serve as VLC-based access points to the RF wireless communications network and/or allowing the devices to provide bridges via VLC links to extend coverage of the RF wireless communications network). Alternatively or additionally, the IP-based RF wireless unit may provide a backhaul for the VLC as well as an uplink connection for the VLC. This allows the IP-based RF wireless unit to serve as an RF-based access points to the VLC network and/or allows RF links to act as bridges that extends coverage of a VLC network. In addition, the IP-based RF wireless unit itself may serve as an RF access point to communicate with RF clients and/or communicate with other the IP-based RF wireless units to extent the RF signal coverage. Thus, it will be appreciated that by utilizing the multifunctional, smart LED devices according to embodiments of the invention, a hybrid VLC and IP-based RF system can be formed that utilizes the smart LED devices to provide VLC communication and extend an IP-based RF wireless communication network, as well as provide additional forms of access for both networks. The system may further include smart LED servers, which also provide illumination, bi-directional VLC, and IP-based RF wireless connectivity. 
         [0020]      FIG. 1A  is a diagram providing an exemplary illustration of the configuration of a multi-functional smart LED system, with smart LED devices  10  having integrated VLC and IP-based RF capabilities being used for lighting applications. A terminal  11  (for example, a computing device with VLC and IP-based RF communication capabilities) near one or more smart LED devices  10  can communicate with a server  13  through an RF gateway  12  via multiple different pathways, which may include, for example, VLC or IP-based RF communications between the terminal  11  and a smart LED device  10 , as well as RF communications between smart LED devices  10  and RF communications between a smart LED device  10  and the RF gateway  12 . 
         [0021]      FIG. 1B  is a diagram providing an exemplary illustration of the configuration of a multi-functional smart LED system, with smart LED devices  10  having integrated VLC and IP-based RF capabilities and being used for a display or signage application. In an exemplary display application, the illumination from multi-functional smart LED devices  10  is used as backlight  14  for a display panel such as LCD. In an exemplary signage application, the illumination from multi-functional smart LED devices  10  is used as backlight  14  for a sign such as an advertisement board. Similar to the discussion above with respect to  FIG. 1A , a terminal  11  near the smart LED devices  10  can communicate with a server  13  through an RF gateway  12  via multiple different pathways, which may include, for example, VLC or IP-based RF communications between the terminal  11  and a smart LED device  10 , as well as RF communications between a smart LED device  10  and the RF gateway  12 . 
         [0022]      FIG. 2  is a block diagram showing components of a multi-functional smart LED device  200  in an exemplary embodiment. The smart LED device  200  includes an IP-based RF wireless unit  20  for providing IP-based wireless connectivity functions, a LED or LED array  24  with a VLC unit  23  for utilizing the LED or LED array  24  for VLC, and a control unit  21  for integrating RF-based communications carried out by the IP-based RF wireless unit  20  with VLC-based communications carried out by the VLC unit  23  with LED or LED array  24 . 
         [0023]    The IP-based RF wireless unit  20  includes, for example, a wireless transceiver (e.g., a WiFi-capable transceiver), and it is capable of receiving and transmitting signals at RF-level frequencies. Internet Protocol (IP) is the set of standards responsible for ensuring that data packets transmitted over the Internet are routed to their intended destinations. The VLC unit  23  includes, for example, a LED driver to power up the LEDs, a VLC modulator to switching the LEDs on/off corresponding to its input data (which may be implemented as or similar to the digital dimming port of a LED driver). The control unit  21  includes, for example, a processor (e.g., a microcontroller) to process commands and data communicated among the RF wireless unit  20 , the VLC unit  23  and other devices, and to coordinate their operations. The memory  22 , for example, a non-volatile memory (e.g., flash memory or EEPROM), is used to store program(s) and data for the control unit  21 . Once the whole smart LED system is powered up, the control unit  21  reads the program and data in the memory  22 . The LED or LED array  24  may be a single LED or arrangement of LEDs suitable for various applications, such as lighting, display and signage applications. Depending on the LED driver in the VLC unit  23 , the LEDs may be connected in series or in parallel or both. 
         [0024]      FIG. 3A  is a block diagram illustrating communication pathways for the exemplary smart LED device depicted in  FIG. 2  in a situation where the VLC functionality of the smart LED device is being used for information broadcasting or data transmission (e.g., including broadcasting address, position, and/or identification information). The control unit  21  controls the IP-based RF wireless unit  20  (e.g., to set it to be in transmit mode or in receive mode). The memory  22  stores instructions (e.g., processor-executable instructions, part of a program) for the control unit  21  to execute. The memory  22  may also be used to store data to be used in a VLC information broadcast or to be transmitted via VLC (e.g., the data for broadcast or transmission, as well as commands related thereto, may be received via the IP-based RF wireless unit  20 , with the control unit  21  causing the data and/or commands to be stored at the memory  22 ). The control unit  21  further controls the VLC unit  23  (e.g., pursuant to a received command) to utilize the LED or LED array  24  for the VLC information broadcast or VLC data transmission (e.g., by instructing a LED driver of the VLC unit  23  to modulate light from the LED or LED array  24  with the data for broadcast or transmission from the memory  22 ). 
         [0025]    It will be appreciated that the LED light is modulated to broadcast or transmit information without visibly affecting the illumination function performed by the LED or LED array  24 . It will further be appreciated that the specific pathways described above and depicted in  FIG. 3A  are merely exemplary, and that other implementations of these pathways and smart LED device components are achievable without departing from the inventive principles (e.g., by setting up a direct connection between VLC unit  23  and memory  22  such that the VLC unit  23  directly obtains the data for broadcast; or by using a separate buffer for the data to be broadcast such that the data for broadcast does not need to be stored at memory  22 ). This also applies to other figures of the application that will be discussed further below, which are also merely exemplary and not intended to limit the scope of the invention to only the depicted pathways and configurations. 
         [0026]      FIG. 3B  is a block diagram illustrating communication pathways for the exemplary smart LED device depicted in  FIG. 2  in a situation where the VLC functionality of the smart LED device is being used for bi-directional communication. The operation of the smart LED device  200  according to  FIG. 3B  is similar to  FIG. 3A  as discussed above, except that  FIG. 3B  further illustrates that information and/or commands may also be carried from the VLC unit  23  to the IP-based RF wireless unit  20  via the control unit  21 . Such information and/or commands may be received via a VLC receiver of the VLC unit  23 . Like in  FIG. 3A , the control unit  21  buffers the data, performs reformatting as needed for the VLC unit  23  and the IP-based RF wireless unit  20  to interact, and sets the operation of the VLC unit  23  and the IP-based RF wireless unit  20  independently either in transmit mode or receive mode.  FIG. 3B  further depicts that the IP-based RF wireless unit  20  is able to act as an uplink backhaul for the VLC link established by the VLC unit  23  (in addition to being a downlink backhaul as depicted in both  FIGS. 3A and 3B ). In this example, the VLC unit  23  includes a LED driver, a VLC modulator and a VLC receiver. 
         [0027]      FIG. 4  is a block diagram showing components of a multi-functional smart LED device  400  in a further exemplary embodiment. The smart LED device  400  of  FIG. 4  is similar to the smart LED device  200  of  FIG. 2 , except that it further includes an image sensor  25  (e.g., a CMOS image sensor). The image sensor  25  device may be, for example, a camera through which pictures or videos can be captured. 
         [0028]      FIG. 5A  is a block diagram illustrating communication pathways for the exemplary smart LED  400  depicted in  FIG. 4  in a situation where the VLC functionality of the smart LED device is being used for information broadcasting or data transmission. The operation of the smart LED device  400  as illustrated in  FIG. 5A  is similar to the operation of smart LED device  200  as depicted in  FIG. 3A  and described above, except that smart LED device  400  further provides for image and/or video information captured by the image sensor  25  to be sent to a server via IP-based RF wireless unit  20 , and for the control unit  21  to be able to control the image sensor  25 . 
         [0029]      FIG. 5B  is a block diagram illustrating communication pathways for the exemplary smart LED device  400  depicted in  FIG. 4  in a situation where the VLC functionality of the smart LED device is being used for bi-directional communication. The operation of the smart LED device  400  as illustrated in  FIG. 5A  is similar to the operation of smart LED device  200  as depicted in  FIG. 3B  and described above, except that smart LED device  400  further provides for image and/or video information captured by the image sensor  25  to be sent to a server via IP-based RF wireless unit  20 , and for the control unit  21  to be able to control the image sensor  25 . 
         [0030]      FIG. 5C  is a block diagram illustrating communications pathways for the exemplary smart LED device  400  depicted in  FIG. 4  in another exemplary embodiment where the image sensor  25  is alternatively be connected to the VLC unit  23 , such that images/data captured by the image sensor  25  is relayed to the control unit via the VLC unit  23 . 
         [0031]      FIGS. 6-8  are exemplary flowcharts illustrating functions that the exemplary smart LED devices discussed above are capable of.  FIG. 6  illustrates a process by which communications including data and/or commands received by the smart LED device via the IP-based RF wireless unit of the smart LED device (stage  601 ) are processed by the control unit (stage  603 ) and broadcasted or transmitted to other smart LED devices and/or networked devices via the VLC unit of the smart LED device (stage  605 ). Processing the data and/or commands via the control unit at stage  603  further includes determining the destination of the data and/or commands (e.g., whether a command is intended for execution by the VLC unit, the IP-based RF wireless unit, or for other devices), reformatting the data and/or commands as needed, and routing/transmitting the data and/or commands to the appropriate destination. 
         [0032]      FIG. 7  illustrates a process by which communications including data and/or commands received by the smart LED device via the VLC unit of the smart LED device (stage  701 ) are processed by the control unit (stage  703 ) and transmitted to other smart LED devices and/or networked devices via the IP-based RF wireless unit of the smart LED device (stage  705 ). Processing the data and/or commands via the control unit at stage  703  further includes determining the destination of the data and/or commands (e.g., whether a command is intended for execution by the VLC unit, the IP-based RF wireless unit, or for other devices), reformatting the data and/or commands as needed, and routing/transmitting the data and/or commands to the appropriate destination. 
         [0033]      FIG. 8  illustrates a process for using the image sensor of a smart LED device, which includes receiving commands for the image sensor via the IP-based RF wireless unit of the smart LED device or the VLC unit of the smart LED device (stage  801 ), executing those commands via the control unit and/or image sensor (stage  803 ) to cause the image sensor to capture image or video information, and transmitting data from the image sensor to other smart LED devices and/or other networked device via the IP-based RF wireless unit of the smart LED device or the VLC unit of the smart LED device (stage  805 ). In an exemplary implementation, the commands sent to the image sensor to control and data received from the image sensor for transmission are routed through the control unit of the smart LED device (e.g., as depicted in  FIGS. 5A and 5B ). 
         [0034]    Further, in exemplary embodiments of the invention, data communicated via the VLC unit and the IP-based RF wireless unit can include address information, position information, and/or identity information associated with various terminals. Smart LED devices as described above can thus be used in “location-aware” applications, such as indoor positioning and/or location-based broadcasting, where address, position, and/or identity information corresponding to terminals is exchanged. 
         [0035]    It will be appreciated that, although the exemplary embodiments discussed above utilize IP-based RF wireless connectivity and VLC, the principles of the invention are not limited thereto. Other Non-Line-of-Sight (NLOS) and Line-of-Sight (LOS) access protocols may be integrated into network devices that are able to extend the coverage and functionality of each of the respective NLOS and LOS protocols used. 
         [0036]    All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
         [0037]    The use of the terms “a” and “an” and “the” and “at least one” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
         [0038]    Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.