Patent Publication Number: US-2022217650-A1

Title: Apparatus and method for adaptively controlling rf transmission power in wireless av system

Description:
BACKGROUND OF THE DISCLOSURE 
     Field of the Disclosure 
     The present disclosure relates to a wireless audio/video (AV) system and, most particularly, to a device and method for adaptively controlling RF transmit power in a wireless AV system. 
     Related Art 
     Recently, there has been a growing demand for high-resolution and high-quality pictures, such as high definition (HD) pictures and ultra-high definition (UHD) pictures, in various fields. With the appearance of new applications, the demands for technology allowing data streams including audio, video (or pictures), or at least a combination thereof, to be wirelessly transmitted, have been increasing. An application field to which such technology can be applied is a wireless audio/video (AV) system. 
     In the wireless AV system, since video data having higher resolution and higher picture quality has relatively more increased information size or bit size being transmitted, as compared to the existing (or conventional) video data, extensive research for wirelessly transmitting high-capacity data at a high speed is being carried out. For example, a wireless AV system may transmit or receive high-capacity data based on wireless communication, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11ad or IEEE 802.11ay, or any other similar ultra-high speed wireless communication. 
     Since the devices that configure the wireless AV system are based on wireless communication, the degree of freedom in installation or deployment is relatively higher than devices being connected via wired connection. Conversely, the unconstrained installation or deployment of devices configuring a wireless AV system includes an issue of degrading RF signal performance. Therefore, a design enabling RF transmit power to be controlled adaptively to a distance and angle between devices, signal interference, and so on, is required in a wireless AV system. 
     SUMMARY OF THE DISCLOSURE 
     Technical Objects 
     A technical object of the present disclosure is to provide a device and method for adaptively controlling RF transmit power in a wireless AV system. 
     Another technical object of the present disclosure is to provide a device and method for transmitting wireless data that can adaptively control RF transmit power in a wireless AV system. 
     A further technical object of the present disclosure is to provide a device and method for receiving a wireless AV signal based on RF transmit power that is adaptively controlled in a wireless AV system. 
     Technical Solutions 
     According to an aspect of the present disclosure, provided herein is a wireless data transmitting device adaptively controlling a radio frequency (RF) transmit power in a wireless audio/video (AV) system. The device includes a controller configured to configure an RF transmit power based on location information of a wireless data receiving device, and a wireless communication unit configured to transmit a wireless AV signal to the wireless data receiving device at the configured RF transmit power, to adjust the configured RF transmit power based on RF reception sensitivity of the wireless data receiving device, and to transmit the wireless AV signal to the wireless data receiving device at the adjusted RF transmit power. 
     In an aspect, the location information of the wireless data receiving device may include information on a distance and angle from the wireless data transmitting device to the wireless data receiving device. 
     In another aspect, the wireless data transmitting device may further include a location information collector collecting location information of the wireless data receiving device. 
     In yet another aspect, the location information collector may transmit a reference signal for collecting the location information to the wireless data receiving device, and the location information collector may collect the location information of the wireless data receiving device based on a frequency that is changed due to a Doppler effect when the reference signal is reflected from the wireless data receiving device. 
     In yet another aspect, the wireless communication unit may transmit a reference signal for collecting the location information to the wireless data receiving device, and the wireless communication unit may collect the location information of the wireless data receiving device based on a frequency that is changed due to a Doppler effect when the reference signal is reflected from the wireless data receiving device. 
     In yet another aspect, the wireless communication unit may be configured to receive information related to the RF reception sensitivity from the wireless data receiving device. 
     In yet another aspect, when a distance from the wireless data transmitting device to the wireless data receiving device is smaller than or equal to a reference distance, the controller may configure the RF transmit power to a low power level. 
     In yet another aspect, the wireless communication unit may increase the configured RF transmit power as the RF reception sensitivity becomes lower, and the wireless communication unit may decrease the configured RF transmit power as the RF reception sensitivity becomes higher. 
     According to another aspect of the present disclosure, provided herein is a wireless data receiving device in a wireless audio/video (AV) system. The device includes a wireless communication unit configured to receive a wireless AV signal being transmitted at a radio frequency (RF) transmit power from a wireless data transmitting device, to measure RF reception sensitivity corresponding to the wireless AV signal, and to transmit information on the measured RF reception sensitivity to the wireless data transmitting device, and a controller configured to reconstruct a video (or picture) and audio from the wireless AV signal. Herein, the RF transmit power may be configured based on location information of the wireless data receiving device and may be adjusted based on information on the measured RF reception sensitivity. 
     In an aspect, the location information of the wireless data receiving device may include information on a distance and angle from the wireless data transmitting device to the wireless data receiving device. 
     In another aspect, the wireless data receiving device may further include a location information responder being used for providing location information of the wireless data receiving device. 
     In yet another aspect, the location information responder may receive a reference signal for collecting the location information from the wireless data transmitting device, and the location information responder may transmit a reflected signal corresponding to the reference signal to the wireless data transmitting device. 
     In yet another aspect, the wireless communication unit may receive a reference signal for collecting the location information from the wireless data transmitting device, and the wireless communication unit may transmit a reflected signal corresponding to the reference signal to the wireless data transmitting device. 
     In yet another aspect, when a distance from the wireless data transmitting device to the wireless data receiving device is smaller than or equal to a reference distance, the RF transmit power may be a low power. 
     In yet another aspect, the RF transmit power may increase as the RF reception sensitivity becomes lower, and the RF transmit power may decrease as the RF reception sensitivity becomes higher. 
     Effects of the Disclosure 
     According to the present disclosure, even if a change occurs in locations of devices, such as distance and angle between devices, re changed, by transmitting a wireless AV signal at an optimal RF transmit power, implementation of a wireless AV system that can increase power consumption efficiency becomes possible. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of a wireless AV system according to an embodiment of the present disclosure. 
         FIG. 2  is a block diagram showing a wireless data transceiving system according to an embodiment of the present disclosure. 
         FIG. 3  is a conceptual diagram of a case where the wireless data transceiving system according to an embodiment of the present disclosure is implemented according to an IEEE 802.11 series communication protocol. 
         FIG. 4  shows a machine state of a wireless AV system according to an embodiment of the present disclosure. 
         FIG. 5  shows a device processing and transmitting pictures (or images) in a wireless AV system according to an embodiment of the present disclosure. 
         FIG. 6  is an exemplary diagram showing a distance and angle from a wireless data transmitting device to a wireless data receiving device. 
         FIG. 7  is a diagram describing a method for measuring a distance and/or angle between a wireless data transmitting device and a wireless data receiving device according to an example of the present disclosure. 
         FIG. 8  is a diagram describing a method for measuring a distance and/or angle between a wireless data transmitting device and a wireless data receiving device according to another example of the present disclosure. 
         FIG. 9  shows a lookup table according to an example of the present disclosure. 
         FIG. 10  is a flowchart showing a method for controlling RF transmit power that is performed by a wireless data transmitting device according to an embodiment of the present disclosure. 
         FIG. 11  is a flowchart showing a method for configuring an RF transmit power according to an embodiment of the present disclosure. 
         FIG. 12  is a flowchart showing a method for controlling an RF transmit power according to an embodiment of the present disclosure. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The following detailed description illustrates embodiments of a device and method for transmitting wireless data and embodiments of a device and method for receiving wireless data that are provided according to the present disclosure. And, such embodiments do not represent the only forms of the present disclosure. The characteristics and features of the present disclosure are described with reference to exemplary embodiments presented herein. However, functions and structures that are similar or equivalent to those of the exemplary embodiments described in the present specification may be included in the scope and spirit of the present disclosure and may be achieved by other intended embodiments. Throughout the present specification, similar reference numerals will be used to refer to similar components or features. Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. 
     In recent years, the design of display devices, such as TVs, has become important, and display panels have become thinner with the development and evolution of technologies for display panels, such as OLED. However, due to the thickness of a driving circuit that is required in order to drive a display panel, there have been restrictions (or limitations) in manufacturing and designing thinner display panels. Therefore, a technology that is capable of separating components excluding components that are mandatorily required to be physically and electrically connected to the display panel, from the display panel, and equipping the physically or electrically separated components to a separate device (hereinafter referred to as a “main device”) is being considered as a promising technology. In this case, a main device and a display device may be configured to exchange image signals and audio signals based on a wireless communication between the main device and the display device. The present disclosure relates to a wireless AV system, or a wireless display system being equipped with a main device and a display device that are provided as physically and/or electrically independent components, wherein media may be played (or reproduced) based on a wireless communication between the devices. 
       FIG. 1  is a block diagram of a wireless AV system according to an embodiment of the present disclosure. 
     Referring to  FIG. 1 , a wireless AV system  10  may include a main device  10 , a display panel device  200 , and a remote control device  300 . 
     The main device  100  may perform an operation of receiving an external signal in a wired or wireless format that is related to audio, video, pictures, images, multimedia, or at least one combination thereof, processing the received external signal by using various methods, so as to generate a data stream or a bitstream, and transmitting the generated data stream or bitstream to the display device  200 . 
     In order to perform such operation, the main device  100  may include an external signal receiver  110 , an external device interface unit  115 , a storage unit  120 , a main controller  130 , a wireless communication unit  140 , and a power supply unit  150 . 
     The external signal receiver  110  may include a tuner  111 , a demodulator  112 , and a network interface unit  113 . 
     The tuner  111  receives an external signal in a wired or wireless format that is related to audio, video, pictures, images, multimedia, or at least one combination thereof. For example, the tuner  111  may select a specific broadcast channel in accordance with a channel selection command and may receive a broadcast signal corresponding to the selected specific broadcast channel. 
     The demodulator  112  may separate the received broadcast signal to a video signal, an image signal, a picture signal, an audio signal, and a data signal related to a broadcast program. And, then, the demodulator  112  may reconstruct (or restore or recover) the separated video signal, image signal, picture signal, audio signal, and data signal to a format that can be outputted. 
     The external device interface unit  115  may receive an application or an application list of a nearby (or neighboring) external device and may deliver (or communicate) the application or application list to the main controller  130  or storage unit  120 . 
     The external device interface unit  115  may provide a connection path between the wireless AV system  100  and an external device. The external device interface unit  115  may receive an external input signal including audio, video, pictures, images, multimedia, or at least one combination thereof from an external device, which is connected to the main device  100  via wired or wireless connection, and may then deliver the received external input signal to the main controller  130 . The external device interface unit  115  may include multiple external input terminals. The multiple external input terminals may include an RF terminal, an RGB terminal, one or more High Definition Multimedia Interface (HDMI) terminals, a USB terminal, a component terminal, an AV terminal, a CI terminal. 
     An external device that is connectable to the external device interface unit  115  may be any one of a set-top box, a Bluray player, a DVD player, a gaming system, a sound bar, a smart phone, a PC, a USB memory, a home theater system. However, these are merely exemplary. 
     The network interface unit  113  may provide an interface for connecting the main device  100  to a wired/wireless network including an internet network. The network interface unit  113  may transmit or receive data to or from another user or another electronic device through an accessed network or another network that is linked to the accessed network. 
     Additionally, some content data stored in the main device  100  may be transmitted to a user or an electronic device, which is selected from other users or other electronic devices that are pre-registered in the main device  100 . 
     The network interface unit  113  may access a predetermined webpage through an accessed network or another network that is linked to the accessed network. That is, the network interface unit  113  may transmit or receive data to or from a corresponding server by accessing a predetermined webpage through the network. 
     Also, the network interface unit  113  may receive contents or data provided from a content provider or a network operator. That is, the network interface unit  113  may receive contents such as movies, advertisements, games, VODs, and broadcast signals, which are provided from a content provider or a network provider, and related information through the network. 
     Additionally, the network interface unit  113  may receive firmware update information and update files provided from a network operator and may transmit data to an internet or content provider or a network operator. 
     The network interface unit  113  may select and receive a wanted application among applications that are open to public, through the network. 
     The storage unit  120  may store programs for performing processing and control of each signal within the main controller  130 , and then the storage unit  120  may store signal-processed image, voice, or data signals. 
     Additionally, the storage unit  120  may perform a function for temporarily storing image, voice, or data signals that are inputted from the external device interface unit  115  or network interface unit  113 , and the storage unit  120  may also store information related to a predetermined image through a channel memory function. 
     The storage unit  120  may store an application or an application list that is inputted from the external device interface unit  115  or network interface unit  113 . 
     The main controller  130  may control the main device  100  by using a user instruction (or command) that is inputted through the remote control device  300 , or by using an internal program, and may access a network in order to be capable of downloading an application or an application list that is wanted by a user to the main device  100 . 
     The main controller  130  enables user-selected channel information to be outputted along with a processed image or audio signal through a display device  200  or an audio output unit  250 . 
     Additionally, the main controller  130  enables an image signal or audio signal, which is inputted from an external device, e.g., a camera or camcorder, through the external device interface unit  115 , to be outputted through the display device  200  or audio output unit  250  in accordance with according to an external device image playback instruction (or command) that is received through the remote control device  300 . 
     The main controller  130  may perform a control operation so that content stored in the storage unit  120 , received broadcast content, or externally input content can be played back (or reproduced). Such content may be configured in various formats, such as a broadcast image, an externally inputted image, an audio file, a still image, an accessed (or connected) web screen, a document file, and so on. 
     The main controller  130  may decode a video, an image, a picture, a sound, or data related to a broadcast program being inputted through the demodulator  112 , the external device interface unit  115 , or the storage unit  120 . Then, the main controller  130  may process the decoded data in accordance with encoding/decoding methods supported by the display device  200 . Thereafter, the main controller  130  may process the encoded data by using various video/audio processing methods, such as compression and encoding, so as to transmit the corresponding data through a wireless channel, thereby generating a data stream or bitstream. Finally, the main controller  130  may transmit the generated data stream or bitstream to the display device  200  through the wireless communication unit  140 . 
     Depending upon the embodiments, the main controller  130  may also bypass the decoded data, without encoding the decoded data in accordance with the encoding/decoding methods supported by the display device  200 , and may directly transmit the decoded data to the display device  200  through the wireless communication unit  140 . 
     The main controller  130  may be configured to implement the functions, procedures, and/or methods of a processor  1130  of a wireless data transmitting device  1100  that are to be described with reference to each embodiment of the present specification. Layers of the wireless interface protocol may be implemented in the processor  1130 . The main controller  130  may be provided in the form of a system on chip (SoC). 
     The wireless communication unit  140  may be operatively coupled to the main controller  130 , for example, as a combination of a wireless communication chip and an RF antenna. The wireless communication unit  140  may receive a data stream or bitstream from the main controller  130 , may generate a wireless stream by encoding and/or modulating the data stream or bitstream into a format that can be transmitted through a wireless channel, and may transmit the generated wireless stream to the display device  200 . The wireless communication unit  140  establishes a wireless link, and the main device  100  and the display device  200  are connected through the wireless link. The wireless communication unit  140  may be configured based on various wireless communication modes, such as short-range wireless communication including Wi-Fi, Bluetooth, NFC, and RFID, or a mobile communication network (e.g., 3G, 4G, and 5G cellular networks). For example, the wireless communication unit  140  may perform communication by using a communication protocol, such as a standard of the IEEE 802.11 series. 
     Depending upon the embodiments, the wireless communication unit  140  may include a picture processor performing picture processing (encoding, decoding, and so on) functions. In this case, the wireless communication unit  140  may perform an operation of encoding the picture, which is received from the main controller  130 , in accordance with the picture format of the display device  200 . Alternatively, the picture processor may be provided in the main controller  130  and not in the wireless communication unit  140 . In this case, the main controller  130  may perform an operation of encoding the picture of the externally inputted signal in accordance with the picture format of the display device  200 . Alternatively, the picture processor may be provided as an independent body each being connected to the wireless communication unit  140  and the main controller  130 . In this case, the main controller  130  may transmit a picture signal, which is inputted through the external device interface unit  115 , to the picture processor, the picture processor may encode the picture signal and transmit the encoded picture signal to the wireless communication unit  140 , and the wireless communication unit  140  may wirelessly transmit the encoded picture signal to the display device  200 . 
     The power supply unit  150  supplies power to the external signal receiver  110 , the external device interface unit  115 , the storage unit  120 , the main controller  130 , and the wireless communication unit  140 . Methods for receiving power from an external source performed by the power supply unit  150  may include a terminal method and a wireless method. In case the power supply unit  150  receives power by using a wireless method, the power supply unit  150  may include a separate configuration in order to wirelessly receive power. For example, the power supply unit  150  may include a power pick-up unit configured to be magnetically coupled with an external wireless power transmitting device so as to receive wireless power, and a separate communication and control unit configured to perform communication with the wireless power transmitting device in order to receive wireless power and to control transmission and reception of wireless power. 
     The wireless communication unit  140  may also be wirelessly connected to the remote control device  300 , thereby being capable of transferring (or delivering) signals inputted by the user to the main controller  130  or transmitter (or delivering) signals from the main controller  130  to the user. For example, the wireless communication unit  140  may receive or process control signals, such as power on/off, screen settings, and so on, of the main device  100  from the remote control device  300  or may process control signals received from the main controller  130  so that the processed signals can be transmitted to the remote control device  300  in accordance with various communication methods, such as Bluetooth, Ultra Wideband (WB), ZigBee, Radio Frequency (RF), or Infrared (IR) communication, and so on. 
     Additionally, the wireless communication unit  140  may deliver (or communicate) control signals that are inputted from a local key (not shown), such as a power key, a volume key, a setup key, and so on, to the main controller  130 . 
     Subsequently, the display device  200  may process a wireless stream, which is received from the main device  100  through a wireless interface, by performing a reverse process of a signal processing operation that is performed by the main device  100 , and, then, the display device  200  may output a display or audio (or sound). In order to perform such operation, the display device  200  may include a wireless communication unit  210 , a user input interface unit  220 , a panel controller  230 , a display unit  240 , an audio output unit  250 , and a power supply unit  260 . 
     The wireless communication unit  210  may be configured as a combination of a wireless communication chip and an RF antenna. The wireless communication unit  210  is connected to the wireless communication unit  140  of the main device  100  through a wireless link and performs wireless communication with the wireless communication unit  140  of the main device  100 . More specifically, the wireless communication unit  210  receives a wireless stream from the wireless communication unit  140  of the main device  100 , demodulates the received wireless stream, and transmits the demodulated wireless stream to the panel controller  230 . The wireless communication unit  210  may be configured based on various wireless communication modes, such as short-range wireless communication including Wi-Fi, Bluetooth, NFC, and RFID, or a mobile communication network (e.g., 3G, 4G, and 5G cellular networks). For example, the wireless communication unit  210  may perform communication by using a communication protocol, such as a standard of the IEEE 802.11 series. 
     Depending upon the embodiments, the wireless communication unit  210  may include a picture processor performing picture processing (encoding, decoding, and so on) functions. In this case, the wireless communication unit  210  may perform an operation of decoding the picture, which is received from the main device  100 . Alternatively, the picture processor may be provided in the panel controller  230  and not in the wireless communication unit  210 . In this case, the panel controller  230  may perform an operation of decoding the picture, which is received from the wireless communication unit  210 . Alternatively, the picture processor may be provided as an independent body each being connected to the wireless communication unit  210  and the panel controller  230 . In this case, the wireless communication unit  210  may wirelessly receive a picture signal, which is then transmitted to the picture processor. And, the picture processor may decode the picture signal and then transmit the decoded picture signal to the panel controller  230 . 
     The panel controller  230  decodes a signal that is demodulated by the wireless communication unit  210  so as to reconstruct (or recover) a bitstream or data stream. At this point, in case the bitstream or data stream is a compressed stream, the panel controller  230  may decompress or reconstruct the bitstream or data stream. Thereafter, the panel controller  230  may output the bitstream or data stream as a video signal, an image signal, a picture signal, an audio signal, or a data signal related to a broadcast program, and may transmit the signals to the display unit  240 , the audio output unit  250 , and the user input interface unit  220 . 
     The video signal, the picture signal, the image signal, and so on, that are inputted to the display unit  240  may be displayed as a picture corresponding to the inputted picture signal. Alternatively, the picture signal that is processed by the panel controller  230  may be transmitted back to the main device  100  through the wireless communication unit  210  and may then be inputted to an external output device through the external device interface unit  115  of the main device  100 . 
     The audio signal that is processed by the panel controller  230  may be audio-outputted to the audio output unit  250 . Moreover, the audio signal that is processed by the panel controller  230  may be transmitted back to the main device  100  through the wireless communication unit  210  and may then be inputted to an external output device through the external device interface unit  115  of the main device  100 . 
     Meanwhile, the panel controller  230  may control the display unit  240  so as to display a picture (or image). For example, the panel controller  230  may perform control operation, so that a broadcast picture (or image) that is inputted through the tuner  111 , an externally inputted picture (or image) that is inputted through the external device interface unit  115 , a picture (or image) that is inputted through the network interface unit, or a picture (or image) that is stored in the storage unit  120  can be displayed on the display unit  240 . In this case, the picture (or image) that is displayed on the display unit  240  may be a still picture (or image) or a video, and may be a 2D image or a 3D image. 
     The panel controller  230  may be provided (or equipped) with a frame rate conversion (FRC) function. For example, based on the FRC function, the panel controller  230  may convert a reconstructed (or recovered) picture (or image) signal, which is reconstructed (or recovered) by the wireless communication unit  210  or panel controller  230  at a frame rate corresponding to an  8 K display, and may then transfer the converted signal to a T-Con board. 
     The panel controller  230  may be configured to implement the functions, procedures, and/or methods of a processor  1230  included in a wireless data receiving device  1200 , which will be described with reference to each embodiment of the present specification. Additionally, the processor  1230  may be configured to implement the functions, procedures, and/or methods of the wireless data receiving  1200  that will be described with reference to each embodiment of the present specification. 
     The user input interface unit  220  may transmit a signal that is inputted, by the user, to the panel controller  230  or may transmit a signal from the panel controller  230  to the user. For example, the user input interface  220  may receive and process control signals, such as power on/off, screen settings, and so on, of the display device  200  from the remote control device  300 , or may process control signals received from the panel controller  230  so that the processed signals can be transmitted to the remote control device  300  in accordance with various communication methods, such as Bluetooth, Ultra Wideband (WB), ZigBee, Radio Frequency (RF), or Infrared (IR) communication, and so on. 
     The user input interface unit  220  may transmit a control signal, which is inputted through a local key (not shown), such as a power key, a volume key, a setup key, and so on, to the panel controller  230 . 
     The power supply unit  260  supplies power to the wireless communication unit  210 , the user input interface unit  220 , the panel controller  230 , the display unit  240 , and the audio output unit  250 . Methods for receiving power from an external source performed by the power supply unit  260  may include a terminal method and a wireless method. In case the power supply unit  260  receives power by using a wireless method, the power supply unit  260  may include a separate configuration in order to wirelessly receive power. For example, the power supply unit  260  may include a power pick-up unit configured to be magnetically coupled with an external wireless power transmitting device so as to receive wireless power, and a separate communication and control unit configured to perform communication with the wireless power transmitting device in order to receive wireless power and to control transmission and reception of wireless power. 
     The remote control device  300  performs an operation of remotely controlling various features of the main device  100  or the display device  200 , such as power on/off, channel selection, screen setup, and so on. Herein, the remote control device  300  may also be referred to as a “remote controller (or remote)”. 
     Meanwhile, since the main device  100  and the display device  200 , which are shown in  FIG. 1 , are provided only as an example of one embodiment of the present disclosure, some of the illustrated components may be integrated or omitted, or other components may be added according to the specifications of the main device  100  and the display device  200 , which are actually implemented. That is, as necessary, two or more components may be integrated into one component, or one component may be divided into two or more components. In addition, a function that is performed in each block is presented to describe an embodiment of the present disclosure, and a specific operation or device will not limit the scope and spirit of the present disclosure. 
     According to another embodiment of the present disclosure, unlike the example shown in  FIG. 1 , the main device  100  may receive and play-back (or reproduce) an image (or picture) through the network interface unit  113  or the external device interface unit  115  without including the tuner  111  and the demodulator  112 . 
     For example, the main device  100  may be implemented by being divided into an image processing device, such as a set-top box, for receiving broadcast signals or content according to various network services, and a content playback device for playing content input from the image processing device. 
     In this case, an operating method of the wireless AV system  10  according to an embodiment of the present disclosure that will hereinafter be described may be performed not only by the main device  100  and the display device  200 , as described above with reference to  FIG. 1 , but also by one of the divided image processing device, such as the set-top box, or content playback device, which includes an audio output unit  250 . 
     In light of system input/output, the main device  100  may be referred to as a wireless source device that wirelessly provides a source, and the display device  200  may be referred to as a wireless sink device that wirelessly receives a source. The wireless source device and the wireless sink device may implement wireless display (WD) communication technologies that are compatible with standards such as wireless HD, wireless home digital interface (WHDI), WiGig, wireless USB, and Wi-Fi display (WFD, which also known as Miracast). 
     In light of the applications, the main device  100  may be integrated to a form that configures part of a wireless set-top box, a wireless gaming console, a wireless digital video disc (DVD) player, a wireless router, or the like. In this case, the main device  100  may be provided as a wireless communication module or a chip. The display device  200  may be integrated to a form that configures part of a user device or electronic device (e.g., a wireless TV, a wireless monitor, a wireless projector, a wireless printer, a wireless vehicle dashboard display, a wearable device, an augmented-reality (AR) headset, a virtual-reality (VR) headset, or the like) having a display panel so as to display an image and a video. In this case, the display device  200  may be provided in the form of a wireless communication module or chip. 
     The main device  100  and the display device  200  may be integrated to forms that configure parts of a mobile device. For example, the main device  100  and the display device  200  may be integrated into a mobile terminal including a smartphone, a smartpad, a tablet PC, or other types of wireless communication devices, a portable computer having a wireless communication card, a personal digital assistant (PDA), a portable media player, a digital image capturing device, such as a camera or camcorder, or other flash memory devices having wireless communication capabilities. In this case, the main device  100  and the display device  200  may be provided in the form of wireless communication modules or chips. 
     Smartphone users may perform streaming or mirroring of a video and an audio, which are outputted by the users&#39; smartphones, tablet PCs, or other computing devices, to another device, such as a television or a projector, in order to provide a higher resolution display or other enhanced user experience. 
     As described above, the main device  100  may receive an external signal in a wired or wireless format that is related to a medium, such as audio, video, a picture, an image, multimedia, or at least one combination thereof, and the main device  100  may process the received external signal by using various methods, so as to generate a data stream or bitstream, and may transmit the data stream or bitstream to the display device  200  through a wireless interface. 
     Hereinafter, image (or picture)/video/audio data that are transmitted through a wireless interface will be collectively referred to as wireless data. That is, the main device  100  may wirelessly communicate with the display device  200  and may transmit wireless data. Therefore, in light of a wireless data transceiving system  1000 , the main device  100  may be referred to as a wireless data transmitting device  1100 , and the display device  200  may be referred to as a wireless data receiving device  1200 . Hereinafter, the present disclosure will be described in more detail in light of the wireless data transceiving system  1000 . Firstly, a detailed block diagram of the wireless data transceiving system  1000  will be illustrated. 
       FIG. 2  is a block diagram showing a wireless data transceiving system according to an embodiment of the present disclosure. 
     Referring to  FIG. 2 , a wireless data transceiving system  1000  refers to a system that wirelessly transmits and receives a data stream. And, the wireless data transceiving system  1000  includes a wireless data transmitting  1100  and at least one wireless data receiving device  1200 . The wireless data transmitting device  1100  is communicatively coupled to the at least one wireless data receiving device  1200 . 
     According to an aspect, the data may be configured of an audio, a video, a picture, an image, multimedia, or at least one combination thereof. 
     According to another aspect, the data may include a bitstream in the form of a compressed audio, a bitstream in the form of a compressed video, a bitstream in the form of a compressed picture, a bitstream in the form of compressed multimedia, or at least one combination thereof. In this case, the wireless data transceiving system  1000  may also be referred to as a wireless compressed data stream transceiving system. Additionally, the wireless compressed data stream transceiving system  1000  may further include a functional or physical unit for compressing data. 
     Referring to the detailed configuration of each device, the wireless data transmitting device  1100  includes a processor  1130 , a memory  1120 , and a communication unit  1140 , and the wireless data receiving device  1200  includes a communication unit  1210 , a memory  1220 , and a processor  1230 . 
     The processor  1130  may be configured to implement the functions, procedures, and/or methods of the wireless data transmitting device  1100  that are to be described with reference to each embodiment of the present specification. Also, the processor  1230  may also be configured to implement the functions, procedures, and/or methods of the wireless data receiving device  1200  that are to be described with reference to each embodiment of the present specification. Layers of the wireless interface protocol may be implemented in the processors  1130  and  1230 . 
     In light of the display system in  FIG. 1 , the processor  1130  may be configured to perform the function of the main controller  130 . For example, the processor  1130  may decode a video, an image, a picture, a sound, or data related to a broadcast program that are inputted through the demodulator  112 , the external device interface unit  115 , or the storage unit  120 , may process the decoded data by using various video/audio processing methods, such as compression and encoding, so as to transmit the data through a wireless channel, thereby generating a data stream or bitstream, and may transmit the generated data stream or bitstream to the display device  200  through the communication unit  1140 . 
     The memories  1120  and  1220  are operatively coupled with the processors  1130  and  1230  and store various types of information for operating the processors  1130  and  1230 . 
     The communication units  1140  and  1210  are operatively coupled with the processors  1130  and  1230  and wirelessly transmit and/or receive data. The communication units  1140  and  1210  establish a wireless link  11 , and the wireless data transmitting device  1100  and the wireless data receiving device  1200  are inter-connected through the wireless link  11 . The communication units  1140  and  1210  may be configured based on various wireless communication modes, such as short-range wireless communication including Wi-Fi, Bluetooth, NFC, and RFID, or a mobile communication network (e.g., 3G, 4G, and 5G cellular networks). For example, the wireless communication units  1140  and  1210  may perform communication by using a communication protocol, such as a standard of the IEEE 802.11 series. 
       FIG. 3  is a conceptual diagram of a case where the wireless data transceiving system according to an embodiment of the present disclosure is implemented according to an IEEE 802.11 series communication protocol. 
     Referring to  FIG. 3 , a wireless data transceiving system  20  in (A) of  FIG. 3  may include at least one basic service set (hereinafter referred to as ‘BSS’)  21  and  25 . A BSS is a set consisting of an access point (hereinafter referred to as ‘AP’) and a station (STA) that are successfully synchronized and, thus, capable of communicating with each other. Herein, the BSS does not refer to a specific region (or area). 
     For example, a first BSS  21  may include a first AP  22  and one first STA  21 - 1 . A second BSS  25  may include a second AP  26  and one or more STAs  25 - 1  and  25 - 2 . Herein, the first AP  22  may correspond to the communication unit  1140  of  FIG. 2 , and the one or more STAs  25 - 1  and  25 - 2  may correspond to the communication unit  1210  of  FIG. 2 . 
     An infrastructure BSS  21  and  25  may include at least one STA, APs  22  and  26  providing a distribution service, and a distribution system (DS)  27  connecting multiple APs. 
     The distribution system  27  may implement an extended service set (hereinafter referred to as ‘ESS’)  28 , which is extended by being connected to multiple BSSs  21  and  25 . The ESS  28  may be used as a term indicating one network that is configured by connecting one or more APs  22  and  26  through the distribution system  27 . At least one AP being included in one ESS  28  may have a same service set identification (hereinafter referred to as ‘SSID’). 
     A portal  29  may perform the role of a bridge, which connects the wireless LAN network (IEEE 802.11) with another network (e.g., 802.X). 
     In a WLAN having the structure shown in (A) of  FIG. 3 , a network between the APs  22  and  26  and a network between the APs  22  and  26  and the STAs  21 - 1 ,  25 - 1 , and  25 - 2  may be implemented. 
     Meanwhile, unlike the system shown in (A) of  FIG. 3 , the wireless data transceiving system  30  shown in (B) of  FIG. 3  may be capable of performing communication by establishing a network between the STAs without any APs  22  and  26 . A network that is capable of performing communication by establishing a network between the STAs without any APs  22  and  26  is defined as an Ad-Hoc network or an independent basic service set (hereinafter referred to as ‘IBSS’). 
     Referring to (B) of  FIG. 3 , the wireless data transceiving system  30  is a BSS that operates in the Ad-Hoc mode, i.e., an IBSS. Since the IBSS does not include any AP, a centralized management entity that performs a management function at the center does not exist. Therefore, in the wireless data transceiving system  30 , STAs  31 - 1 ,  31 - 2 ,  31 - 3 ,  32 - 4 , and  32 - 5  are managed in a distributed manner. Here, the STAs  31 - 1 ,  31 - 2 ,  31 - 3 ,  32 - 4 , and  32 - 5  may correspond to the communication unit  1140  or the communication unit  1210  of  FIG. 2 . 
     All STAs  31 - 1 ,  31 - 2 ,  31 - 3 ,  32 - 4 , and  32 - 5  included in the IBSS may be configured as mobile STAs and are not allowed to access a distributed system. All of the STAs included in the IBSS establish a self-contained network. 
     An STA that is mentioned in the present specification is a random functional medium including a medium access control (hereinafter referred to as ‘MAC’) and a physical layer interface for a wireless medium according to the regulations of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard and may be used to broadly refer to both an AP and a non-AP STA. 
     An STA that is mentioned in the present specification may be referred to by using various terms, such a mobile terminal, a wireless device, a wireless transmit/receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile subscriber unit, and, simply, a user. 
     Referring back to  FIG. 2 , a communication channel that is established by the communication units  1140  and  1210  may be a network communication channel. In this case, the communication units  1140  and  1210  may establish a tunneled direct link setup (TDLS) in order to avoid or reduce network congestion. Wi-Fi Direct and TDLS are used for setting up relatively short-range communication sessions. The communication channel that establishes a wireless link  11  may be a communication channel of a relatively short range or a communication channel that is implemented by using a physical channel structure, such as Wi-Fi using a variety of frequencies including 2.4 GHz, 3.6 GHz, 5 GHz, 60 GHz, or ultra-wideband (UWB), Bluetooth, and so on. 
     While techniques disclosed in the present specification may generally be described in relation with communication protocols, such as the IEEE 802.11 series standard, it will be apparent that aspects of such techniques may also be compatible with other communication protocols. Illustratively and non-restrictively, wireless communication between the communication units  1140  and  1210  may use orthogonal frequency-division multiplexing (OFDM) schemes. Other various wireless communication schemes including, but not limited to, time-division multiple access (TDMA), frequency-division multiple access (FDMA), code-division multiple access (CDMA), or any random combination of OFDM, FDMA, TDMA, and/or CDMA may also be used. 
     The processors  1130  and  1230  may include an application-specific integrated circuit (ASIC), a different chipset, a logic circuit, and/or a data processor. The memories  1120  and  1220  may include a read-only memory (ROM), a random access memory (RAM), a flash memory, a memory card, a storage medium, and/or another storage device. The communication units  1140  and  1210  may include a baseband circuit for processing radio frequency signals. When an embodiment is implemented as software, the techniques described herein may be implemented as a module (e.g., a procedure, function, and so on) that performs the functions described in the present specification. The module may be stored in the memories  1120  and  1220  and may be executed by the processors  1130  and  1230 . The memories  1120  and  1220  may be implemented inside the processors  1130  and  1230 . Alternatively, the memories  1120  and  1220  may be implemented outside of the processors  1130  and  1230 , and the memories  1120  and  1220  may be communicatively connected to the processors  1130  and  1230  via various well-known means that are disclosed in this technical field. 
     In light of a wireless communication system (i.e., WLAN, Wi-Fi), the wireless data transmitting device  1100  may be referred to as an AP or a personal basic service set control point (PCP) station, and the wireless data receiving device  1200  may be referred to as an STA or a non-personal basic service set control point (non-PCP) station. 
     In light of the input/output of a data stream, the wireless data transmitting device  1100  may be referred to as a wireless source device that wirelessly provides a source, and the wireless data receiving device  1200  may be referred to as a wireless sink device that wirelessly receives a source. The wireless source device and the wireless sink device may implement wireless display (WD) communication technologies that are compatible with standards such as wireless HD, wireless home digital interface (WHDI), WiGig, wireless USB, and Wi-Fi display (WFD, which also known as Miracast). 
     In light of the applications, the wireless data transmitting device  1100  may be integrated to a form that configures part of a wireless set-top box, a wireless gaming console, a wireless digital video disc (DVD) player, a wireless router, or the like. In this case, the wireless data transmitting device  1100  may be provided as a wireless communication module or a chip. And, the wireless data receiving device  1200  may be integrated to a form that configures part of a user device or electronic device (e.g., a wireless TV, a wireless monitor, a wireless projector, a wireless printer, a wireless vehicle dashboard display, a wearable device, an augmented-reality (AR) headset, a virtual-reality (VR) headset, or the like) having a display panel so as to display an image and a video. In this case, the wireless data receiving device  1200  may be provided in the form of a wireless communication module or chip. 
     The wireless data transmitting device  1100  and the wireless data receiving device  1200  may be integrated to forms that configure parts of a mobile device. For example, the wireless data transmitting device  1100  and the wireless data receiving device  1200  may be integrated into a mobile terminal including a smartphone, a smartpad, a tablet PC, or other types of wireless communication devices, a portable computer having a wireless communication card, a personal digital assistant (PDA), a portable media player, a digital image capturing device, such as a camera or camcorder, or other flash memory devices having wireless communication capabilities. In this case, the wireless data transmitting device  1100  and the wireless data receiving device  1200  may be provided in the form of wireless communication modules or chips. 
     Smartphone users may perform streaming or mirroring of a video and an audio, which are outputted by the users&#39; smartphones, tablet PCs, or other computing devices, to another device, such as a television or a projector, in order to provide a higher resolution display or other enhanced user experience. 
       FIG. 4  shows a machine state of a wireless AV system according to an embodiment of the present disclosure. 
     Referring to  FIG. 4 , a wireless AV system may enter or operate in a power off mode  400 , an initial connection establishment mode  410 , a data transfer mode  420 , a stand-by mode  430 , and a connection re-establishment mode  440 . The initial connection establishment mode may also be referred to as an initial wakeup mode, and the connection re-establishment mode may also be simply referred to as a connection establishment mode. 
     The operation mode of the wireless AV system may be changed or transitioned (or shifted) in accordance with a direction of the arrows. For example, the wireless AV system may operate in the power off mode  400 . Thereafter, when power is applied to the wireless AV system, the wireless AV system may enter or shift to the initial connection establishment mode  410 . Additionally, the wireless AV system may operate in the initial connection establishment mode  410 , and, when connection setup is completed, the wireless AV system may enter or shift to the data transfer mode  420 . Additionally, the wireless AV system may operate in the data transfer mode  420 , and, when the wireless AV system is deactivated, connection is cancelled (or the wireless AV system is disconnected), and the wireless AV system may enter or shift to the stand-by mode  430 . Additionally, the wireless AV system may operate in the stand-by mode  430 , and, when the wireless AV system is activated, the wireless AV system wakes up and may, then, enter or shift to the connection re-establishment mode  440 . Furthermore, the wireless AV system may operate in the connection re-establishment mode  440 , and, when connection setup is completed, the wireless AV system may, once again, enter or shift to the data transfer mode  420 . 
     Since the wireless AV system may be configured of a wireless data transmitting device and a wireless data receiving device, a state machine according to  FIG. 4  may be identically applied to each device. That is, each of the wireless data transmitting device and the wireless data receiving device may enter or operate in a power off mode  400 , an initial connection establishment mode  410 , a data transfer mode  420 , a stand-by mode  430 , and a connection re-establishment mode  440 . Furthermore, the mode shift or entering of the wireless data transmitting device and the wireless data receiving device may also be carried out according to the same method as the above-described mode shift or entering of the wireless AV system. 
     The operation of the wireless data transmitting device for each mode may be performed by the main controller  130  of  FIG. 1  or the processor  1130  of  FIG. 2 , and by the wireless communication unit  140  of  FIG. 1  or the communication unit  1140  of  FIG. 2 . 
     Additionally, the operation of the wireless data receiving device for each mode may be performed by the panel controller  230  of  FIG. 1  or the processor  1230  of  FIG. 2 , and by the wireless communication unit  210  of  FIG. 1  or the communication unit  1210  of  FIG. 2 . 
     In the present specification, activation of the wireless data transmitting device may include operations or functions or meanings according to various embodiments. As an example, the activation of the wireless data transmitting device may include an operation of turning on a picture-related data transmission function (turn on operation). As another example, the activation of the wireless data transmitting device may include an operation of receiving a power on signal from a remote controller and turning on the power of the wireless data transmitting device (power on operation). 
     In the present specification, deactivation of the wireless data transmitting device may include operations or functions or meanings according to various embodiments. As an example, the deactivation of the wireless data transmitting device may include an operation of turning off a picture-related data transmission function (turn off operation). As another example, the deactivation of the wireless data transmitting device may include an operation of receiving a power off signal from a remote controller and turning on the power of the wireless data transmitting device (power off operation). In any case, even if the wireless data transmitting device is deactivated, the communication unit of the wireless data transmitting device is normally operated. And, therefore, basic communication between the wireless data transmitting device and the wireless data receiving device may continue to be maintained. 
     The activation or deactivation of the wireless data transmitting device may be detected and managed by the main controller  130  of  FIG. 1  or the processor  1130  of  FIG. 2 . 
     In the present specification, activation of the wireless data receiving device may include operations or functions or meanings according to various embodiments. As an example, the activation of the wireless data receiving device may include an operation of turning on a picture-related data reception function (turn on operation). As another example, the activation of the wireless data receiving device may include an operation of receiving a power on signal from a remote controller and turning on the power of the wireless data receiving device (power on operation). As yet another example, the activation of the wireless data receiving device may include an operation of turning on the power of a display unit (power on operation). 
     In the present specification, deactivation of the wireless data receiving device may include operations or functions or meanings according to various embodiments. As an example, the deactivation of the wireless data receiving device may include an operation of turning off a picture-related data reception function (turn off operation). As another example, the deactivation of the wireless data receiving device may include an operation of receiving a power off signal from a remote controller and turning off the power of the wireless data receiving device (power off operation). As yet another example, the deactivation of the wireless data receiving device may include an operation of turning off the power of a display unit (power off operation). In any case, even if the wireless data receiving device is deactivated, the communication unit of the wireless data receiving device is normally operated. And, therefore, basic communication between the wireless data transmitting device and the wireless data receiving device may continue to be maintained. 
     The activation or deactivation of the wireless data receiving device may be detected and managed by the panel controller  230  of  FIG. 1  or the processor  1230  of  FIG. 2 . 
     Hereinafter, a device and method for adaptively controlling a RF transmit power in a wireless AV system will be disclosed. 
       FIG. 5  shows a device processing and transmitting pictures (or images) in a wireless AV system according to an embodiment of the present disclosure. 
     Referring to  FIG. 5 , a wireless AV system  50  includes a wireless data transmitting device  510  and a wireless data receiving device  520 . The wireless data transmitting device  510  according to the present embodiment may be the main device  100  of  FIG. 1 , and the wireless data receiving device  520  may be the display device  200  of  FIG. 1 . 
     The wireless data transmitting device  510  includes a location information collector  511 , a controller  512 , a picture processor  513  performing picture encoding or decoding function(s), and a wireless communication unit  514 . The picture processor  513  may be provided as a functional element of the controller  512 , or may be provided as a functional element of the wireless communication unit  514 . The wireless communication unit  514  may perform the same function as the wireless communication unit  140  of  FIG. 1 . The controller  512  perform the same function as the main controller  130  of  FIG. 1 . 
     The wireless data receiving device  520  includes a wireless communication unit  521 , a location information responder  522 , a controller  523 , and a picture processor  524  performing picture encoding or decoding function(s). The picture processor  524  may be provided as a functional element of the controller  523 , or may be provided as a functional element of the wireless communication unit  521 . The wireless communication unit  521  may perform the same function as the wireless communication unit  210  of  FIG. 1 . The controller  523  may perform the same function as the panel controller  230  of  FIG. 1 . 
     Hereinafter, organic connectivity relation and operation between each component will be described in more detail. 
     The location information collector  511  of the wireless data transmitting device  510  is configured to collect location information of the wireless data receiving device  520 . Herein, the location information of the wireless data receiving device  520  may include information on a distance or angle or distance and angle from the wireless data transmitting device  510  to the wireless data receiving device  520 , as shown in  FIG. 6 . 
       FIG. 6  is an exemplary diagram showing a distance and angle from a wireless data transmitting device to a wireless data receiving device. That is, the location information collector  511  may collect information on a distance or angle or distance and angle from the wireless data transmitting device  510  to the wireless data receiving device  520 . 
     As an example, the location information collector  511  may collect information on the distance and/or angle by measuring a distance or angle from the wireless data transmitting device  510  to the wireless data receiving device  520 . 
     There may exist various methods for measuring the distance and/or angle. 
     In an aspect, the location information collector  511  may measure the distance and/or angle by using a Doppler effect. 
       FIG. 7  is a diagram describing a method for measuring a distance and/or angle between a wireless data transmitting device and a wireless data receiving device according to an example of the present disclosure. This is a case where a separate antenna for the location information is used. 
     Referring to  FIG. 7 , the location information collector  511  may be provided with a separate antenna for performing location information collection, and the location information responder  522  may be provided with a separate antenna for performing location information response. 
     The location information collector  511  transmits a reference signal for collecting location information. Herein, the reference signal has a specific frequency Fo, which, for example, may belong to an ultra-high frequency band having strong directivity (i.e., 60 GHz). A reference signal that is transmitted from the location information collector  511  is reflected after reaching the location information responder  522 , and the frequency of such reflected signal is transitioned (or changed) to Fr by the Doppler effect. That is, a reference signal of frequency Fo becomes a reflected signal having its frequency transitioned (or changed) to Fr, by the location information responder  522 , which is then returned to the location information collector  511 . 
     At this point, when a time starting from a time point where the reference signal is transmitted from the location information collector  511  to a time point where a reflected signal is returned (i.e., time of flight) is given as Tf, a distance between the wireless data transmitting device  510  and the wireless data receiving device  520  may be represented as 3×10 8  (m/s)×Tf. Additionally, the location information collector  511  may determine angles and locations of the wireless data transmitting device  510  and the wireless data receiving device  520  based on a relationship between frequencies Fo and Fr. The above-described location information collector  511  may be provided as a functional element of the controller  512 , or may be provided as a functional element of the wireless communication unit  514 . 
       FIG. 8  is a diagram describing a method for measuring a distance and/or angle between a wireless data transmitting device and a wireless data receiving device according to another example of the present disclosure. This is a case where a separate antenna for the location information is not provided. 
     Referring to  FIG. 8 , the location information collector  511  may use an antenna of the wireless communication unit  514  in order to perform location information collection, and the location information responder  522  may use an antenna of the wireless communication unit  521  in order to perform location information response. In this case, the location information collector  511  may be provided as a functional element of the controller  512 , and the location information responder  522  may be provided as a functional element of the controller  523 . 
     The location information collector  511  performs control operation enabling the wireless communication unit  514  to transmit a reference signal for collecting location information. Herein, the reference signal has a specific frequency Fo, which, for example, may belong to an ultra-high frequency band having strong directivity (i.e., 60 GHz). A reference signal that is transmitted from the wireless communication unit  514  is reflected after reaching the wireless communication unit  521 , and the frequency of such reflected signal is transitioned (or changed) to Fr by the Doppler effect. That is, a reference signal of frequency Fo becomes a reflected signal having its frequency transitioned (or changed) to Fr, by the wireless communication unit  521 , which is then returned to the wireless communication unit  514 . 
     Additionally, the location information collector  511  may calculate a distance, angle, and location between the wireless data transmitting device  510  and the wireless data receiving device  520  based on a time Tf starting from a time point where the reference signal is transmitted to a time point where a reflected signal is returned, and a relationship between frequencies Fo and Fr. For example, a distance between the wireless data transmitting device  510  and the wireless data receiving device  520  may be represented as 3×10 8  (m/s)×Tf. 
     In another aspect, the location information collector  511  may measure the distance by using long-range voice recognition. 
     In yet another aspect, the location information collector  511  may collect information related to the distance and/or angle through an external input (GPS and/or other location sensing equipment). 
     Referring back to  FIG. 5 , when the location information collector  511  collects the location information, the location information collector  511  inputs the collected location information to the controller  512  and the wireless communication unit  514 . 
     The controller  512  may, for example, store or manage a lookup table indicating the RF transmit power according to the location information. 
       FIG. 9  shows a lookup table according to an example of the present disclosure. 
     Referring to  FIG. 9 , an actual RF transmit power may be determined by functions of a reference RF transmit power, a power correction coefficient, and an angle correction coefficient. Herein, the power correction coefficient and angle correction coefficient may be determined by distance and/or angle information that is collected by the location information collector  511 . For example, when the distance is 1 m, the power correction coefficient is 0.1, and when the distance is 2 m, the power correction coefficient is 0.15. 
     Additionally, according to 4 different angular ranges, the angle correction coefficient may be defined as 5, 7, 9, and 10. For example, when the angle is within a range of 0˜30 degrees, the angle correction coefficient=5, when the angle is within a range of 30˜60 degrees, the angle correction coefficient=7, when the angle is within a range of 60˜90 degrees, the angle correction coefficient=9, and when the angle is within a range of 90˜180 degrees, the angle correction coefficient=10. 
     Therefore, when the distance is 1 m and the angle correction coefficient is 7, the actual RF transmit power becomes 10 dBm (reference RF transmit power)*0.1 (power correction coefficient)*7 (angle correction coefficient)=7 dBm. 
     The controller  512  may calculate the actual RF transmit power by substituting the distance and/or angle information, which is provided by the location information collector  511 , into the lookup table. According to the present embodiment, when a distance that is measured by the location information collector  511  is equal to or less than a reference distance (e.g., when Distance=1 m, in the lookup table of  FIG. 9 ), the controller  512  configures the RF transmit power to a low power (e.g., 5, 7, 9 dBm) that is lower than the reference RF transmit power (10 dBm). 
     Values of the reference RF transmit power, the power correction coefficient and angle correction coefficient according to the distance, and the RF transmit power corresponding to the correction coefficients, which are given in the lookup table of  FIG. 9 , are merely exemplary. And, therefore, it will be apparent that such values may be variously modified and designed. 
     The controller  512  configures the RF transmit power, which is based on the lookup table, as the RF transmit power of the wireless communication unit  514 . And, the wireless communication unit  514  transmits a wireless AV signal at the configured RF transmit power. 
     The RF transmit power, which is configured as described above, may be fixed during an initial installation and may be stored in the location information collector  511  or the controller  512 . And, when a location relationship between the wireless data transmitting device  510  and the wireless data receiving device  520  is changed (e.g., when a physical movement (or relocation) of the wireless data transmitting device  510  or wireless data receiving device  520  occurs), the controller  512  may correct the RF transmit power as much as a difference value between the location information during the initial installation and the changed location information. 
     Referring back to  FIG. 5 , the wireless communication unit  514  transmits a wireless AV signal, at an RF transmit power, which is configured by the controller  512 , to the wireless data receiving device  520 . In this case, the wireless data receiving device  520  receives the wireless AV signal, which is being transmitted at the configured RF transmit power, from the wireless data transmitting device  510 . 
     The wireless communication unit  521  measures an RF reception sensitivity corresponding to the received wireless AV signal, so as to generate feedback information related to the measured RF reception sensitivity, and, then, transmits the generated feedback information to the wireless data transmitting device  510 . Regarding the measurement of the RF reception sensitivity, the wireless communication unit  521  may also be provided with a separate transmission antenna for measuring the RF reception sensitivity and transmitting feedback information, which corresponds to the measured result. 
     The wireless communication unit  514  may receive the feedback information related to the RF reception sensitivity and may adjust the configured RF transmit power based on the RF reception sensitivity. Thereafter, the wireless communication unit  514  performs an operation of transmitting the wireless AV signal to the wireless data receiving data  520  at the adjusted RF transmit power. For example, the wireless communication unit  514  may increase the configured RF transmit power as the RF reception sensitivity becomes lower, and the wireless communication unit  514  may decrease the configured RF transmit power as the RF reception sensitivity becomes higher. That is, the wireless communication unit  514  may determine an optimal RF transmit power by combining the collected location information and the RF reception sensitivity. 
     By calculating the distance between the wireless data transmitting device and the wireless data receiving device and the corresponding locations, as described above, when the distance is closer, or when the RF reception sensitivity is satisfactory (or good), the wireless data transmitting device may operate in a low power mode. Furthermore, even if the distance and locations change, the RF transmit power may be corrected in comparison with the existing distance and locations. When the user installs or deploys a wireless data transmitting device and a wireless data receiving device, the user may know the location or distance that ensures optimal RF performance. 
       FIG. 10  is a flowchart showing a method for controlling RF transmit power that is performed by a wireless data transmitting device according to an embodiment of the present disclosure. 
     Referring to  FIG. 10 , a wireless data transmitting device collects location information of a wireless data receiving device (S 1000 ). Herein, the location information of a wireless data receiving device may include information on a distance or angle or distance and angle from the wireless data transmitting device to the wireless data receiving device, as shown in  FIG. 6 . That is, the wireless data transmitting device may collect information on a distance or angle or distance and angle from the wireless data transmitting device to the wireless data receiving device. 
     As an example, the wireless data transmitting device may collect information on the distance and/or angle by measuring a distance or angle from the wireless data transmitting device to the wireless data receiving device. There may exist various methods for measuring the distance and/or angle. 
     In an aspect, the wireless data transmitting device may measure the distance and/or angle by using a Doppler effect. For example, the wireless data transmitting device may measure and collect location information according to the method described in  FIG. 7  to  FIG. 8 . 
     In another aspect, the wireless data transmitting device may measure the distance by using long-range voice recognition. 
     In yet another aspect, the wireless data transmitting device may collect information related to the distance and/or angle through an external input (GPS and/or other location sensing equipment). 
     The wireless data transmitting device configures an RF transmit power based on the collected location information (S 1005 ). 
     As an example, the wireless data transmitting device may configure the RF transmit power based on the lookup table shown in  FIG. 9  and the corresponding embodiment. 
     As another example, the wireless data transmitting device may configure the RF transmit power according to the method shown in  FIG. 11 . 
       FIG. 11  is a flowchart showing a method for configuring an RF transmit power according to an embodiment of the present disclosure. 
     Referring to  FIG. 11 , the wireless data transmitting device determines whether a distance is greater than, equal to, or smaller than a specific threshold value x (S 1100 ). 
     If the distance is smaller than x, the wireless data transmitting device may configure the RF transmit power to a low power level (S 1105 ). Conversely, if the distance is greater than or equal to x, the wireless data transmitting device may configure the RF transmit power to a high power level (S 1110 ). 
     Referring back to  FIG. 10 , the wireless data transmitting device transmits a wireless AV signal to the wireless data receiving device at the configured RF transmit power (S 1010 ). 
     The wireless data transmitting device receives feedback information related to the RF reception sensitivity from the wireless data receiving device (S 1015 ). 
     The wireless data transmitting device adjusts the RF transmit power based on the feedback information (S 1020 ). For example, the wireless data transmitting device may increase the configured RF transmit power as the RF reception sensitivity becomes lower, and the wireless data transmitting device may decrease the configured RF transmit power as the RF reception sensitivity becomes higher. 
       FIG. 12  is a flowchart showing a method for controlling an RF transmit power according to an embodiment of the present disclosure. 
     Referring to  FIG. 12 , the wireless data transmitting device determines whether an RF reception sensitivity is greater than, equal to, or smaller than a specific threshold value y (S 1200 ). 
     If the RF reception sensitivity is greater than y, the wireless data transmitting device may adjust the RF transmit power to a decreased level (S 1205 ). Conversely, if the RF reception sensitivity is less than or equal to y, the wireless data transmitting device may adjust the RF transmit power to an increased level (S 1210 ). 
     Referring back to  FIG. 10 , Thereafter, the wireless data transmitting device transmits the wireless AV signal, to the wireless data receiving data, at the adjusted RF transmit power (S 1025 ). 
     Since the device and method for receiving wireless data or the device and method for transmitting wireless data according to the above-described embodiments of the present disclosure do not mandatorily require all of the components or operations that are described above, the device and method for receiving wireless data or the device and method for transmitting wireless data may be performed by including all or part of the above-described components or operations. Additionally, the above-described embodiments of the device and method for receiving wireless data or the device and method for transmitting wireless data may be performed in combination with each other. Furthermore, the above-described components or operations are not mandatorily required to be performed in the order that is described above, and, therefore, it is also possible for components or operations (or process steps) that are described in a later order to be performed before the components or operations (or process steps) that are described in an earlier order. 
     The foregoing description has been presented merely to provide an exemplary description of the technical idea of the present disclosure, and it will be apparent to those skilled in the art to which the present disclosure pertains, that various changes and modifications in the embodiments described herein can be made without departing from the scope and spirit of the present disclosure. Therefore, the embodiments of the present disclosure described above can be implemented separately or in combination with each other. 
     The embodiments disclosed herein are provided not to limit the technical idea of the present disclosure but to describe the present disclosure, and the scope of the technical idea of the present disclosure should not be limited to these embodiments. The scope of the present disclosure should be interpreted by the following claims, and all technical ideas within the scope of equivalents thereto should be construed as being included in the scope of the present disclosure.