Patent Publication Number: US-2012042102-A1

Title: Portable electric device and display mirroring method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This U.S. non-provisional patent application claims priority under 35 U.S.C. §119 of Korean Patent Application No. 10-2010-0078476, filed on Aug. 13, 2010, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND 
     1. Field of the Invention 
     The present disclosure herein relates to a portable electric device, and more particularly, to a portable electric device capable of sharing multimedia contents by a wireless communication and a display mirroring method of the portable electric device. 
     2. Description of the Related Art 
     Advances in digital signal processing, storage media, and transmission methods have made it possible to change from voice information services to multimedia services. Various multimedia services such as digital TV services, internet protocol television (IPTV) services, and video on demand (VOD) services, and advances in terminal technology have caused increasing demands for user devices such as portable electric devices for freely accessing and displaying multimedia contents such as digitalized videos, graphics, and audio data. Along with this, new techniques such as a wireless data sharing technology and a display mirroring technique for sharing a screen by wireless connection are applied to recent user devices. 
     For wireless data sharing and display mirroring, it is necessary to transmit data smoothly between remote user devices. For smooth data transmission between user devices, limiting factors such as data transmission rate, bandwidth, and power consumption should be considered. If such limiting factors as data transmission rate, bandwidth, and power consumption are not sufficiently considered, there may be a time delay between user devices during wireless data sharing or display mirroring. In addition, due to the resolution difference between user devices, the quality of a screen shared or mirrored by wireless connection may be decreased. 
     SUMMARY 
     The present disclosure provides a portable electric device formed with a single board to simultaneously decode encoded data and transmit the encoded data. 
     The present disclosure provides a portable electric device capable of sharing multimedia contents by wireless without time delay or image deterioration, and a display mirroring method of the portable electric device. 
     The present disclosure also provides a portable electric device not requiring a transcoding operation during data transmission, and a display mirroring method of the portable electric device. 
     The present disclosure also provides a portable electric device that can perform bidirectional display mirroring and data sharing, and a display mirroring method of the portable electric device. 
     Additional aspects and utilities of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present general inventive concept 
     The foregoing and other features and utilities of the present general inventive concept can be achieved by providing an electronic apparatus including a transceiver, a decoding unit, and a controller to control the transceiver and the decoding unit to simultaneously transmit a source file having encoded data to an external apparatus without decoding the encoded data of the source file and decode the encoded data of the source file. 
     The transceiver, the decoding unit, and the controller may be embedded in a single integrated chip. 
     The apparatus may further include a storage unit having a single common terminal connected to the transceiver and the decoding unit of the single integrated chip such that the source file is read and simultaneously transmitted to both the transceiver and the decoding unit. 
     The source file comprises a first portion and a second portion, the decoding unit may receive and decode the first portion of the stored source file, and the transceiver may receive and transmit the second portion of the stored source file when the decoding unit receives and decodes the second portion of the stored source file. 
     The source file may be selected to be transmitted to the external apparatus according to a selection signal during decoding the first portion of the stored source file so that the second portion of the source file is simultaneously decoded and transmitted to the external apparatus. 
     The apparatus may further include a selection unit to generate a selection signal as a command corresponding to selection of one of mirroring modes. 
     The controller may select the external apparatus and read the source file and simultaneously transmit the read source file to the transceiver and the decoding unit according to the selection of the external apparatus. 
     The transceiver may receive a second source file having encoded data from the external apparatus, and the decoding unit may decode the encoded data of the received second source file and output the decoded data to be displayed as a second image on a screen. 
     The foregoing and other features and utilities of the present general inventive concept can be achieved by providing an electronic apparatus including a single integrated chip formed with a transceiver, a decoding unit, and a controller as a single monolithic body, wherein the controller to control the transceiver and the decoding unit to simultaneously transmit a source file having encoded data to an external apparatus without decoding the encoded data of the source file and decode the encoded data of the source file. 
     The apparatus may further include a single integrated chip having a common terminal to be connected to a storage unit storing the source file so that the transceiver and the decoding unit simultaneously receives the source file from the storage unit. 
     The apparatus may further include a storage unit to store the source file, wherein the controller controls the storage unit, the transceiver, and the decoding unit such that the source file is read from the storage unit and the read source file is simultaneously transmitted the transceiver and the decoding unit. 
     The source file may include a first portion and a second portion, the decoding unit may receive and decode the first portion of the stored source file, and the transceiver may receive and transmit the second portion of the stored source file when the decoding unit receives and decodes the second portion of the stored source file. 
     The apparatus may further include a selection unit to select at least one of the first portion and the second portion. 
     The source file may include source files, and at least one of the source files may be selected according to a selection of a selection unit connected to the single integrated chip such that the selected source file is simultaneously transmitted to the transceiver and the decoding unit. 
     The controller may control the transceiver to transmit the source file without decoding by the decoding unit to the external apparatus in a first mirroring mode, and the controller may control the transceiver to receive another source file from the external apparatus in a second mirroring mode. 
     The source file may include sub-source files, and the controller may generate a list signal representing the sub-source files, select at least one of the sub-source files, and control the selected at least one of the sub-files to be simultaneously transmitted to the transceiver and the decoding unit. 
     The apparatus may further include a selection unit to select the external apparatus and the source file such that the selected source file is simultaneously transmitted to the decoding unit and the selected external apparatus through the transceiver. 
     The foregoing and other features and utilities of the present general inventive concept can be achieved by providing an electronic apparatus including a storage unit to store a source file with encoded data, a single integrated chip connected to the storage unit, and having a transceiver, a decoding unit, and a controller to control the transceiver and the decoding unit to simultaneously receive the source file and decode the source file and transmit the source file to an external apparatus; and a display unit connected to the single integrated chip to display the decoded source file. 
     The transceiver may be an RF transceiver to wirelessly communicate with an external apparatus. 
     The apparatus may further include a housing to accommodate the storage unit, the single integrated chip, and the display unit therein, and to communicate with the external apparatus through the transceiver. 
     The apparatus may further include a selection unit connected to the single integrated chip to select the external apparatus and the source file. 
     The display unit may be a touch screen to display the decoded source file, and the selection unit may be included in the touch screen to generate a selection signal to select the apparatus and the source file. 
     The foregoing and other features and utilities of the present general inventive concept can be achieved by providing a method of an electronic apparatus, the method including storing a source file with encoded data in a storage unit, and transmitting the stored source file from the storage unit to a single integrated chip having transceiver, a decoding unit, and a controller to control the transceiver and the decoding unit to receive the source file and simultaneously decode the source file and transmit the source file to an external apparatus. 
     The method may further include displaying the decoded source file on a display unit. 
     The method may further include selecting the external apparatus and the source file using a selection unit connected to the signal integrated chip. 
     Embodiments of the inventive concept provide display mirroring methods of a user device including: performing an operation of transmitting compressed first source files and first display information corresponding to the first source files to another user device by wireless in response to a first type display mirroring request in parallel with an operation of decoding the first source files; and displaying a decoding result of the first source files based on the first display information in parallel with a displaying operation of the other user device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and/or other aspects and features of the present general inventive concept will become apparent and more readily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a view illustrating an exemplary structure of a wireless sharing system according to an embodiment of the inventive concept; 
         FIG. 2  is a view illustrating frequency characteristics of wireless universal serial bus (USB) that can be used for display mirroring according to an embodiment of the inventive concept; 
         FIG. 3  is a view illustrating exemplary overall structures of first and second user devices illustrated in  FIG. 1 ; 
         FIGS. 4 through 6  are views illustrating a first type display mirroring operation according to embodiments of the inventive concept; 
         FIGS. 7 through 9  are views illustrating a second type display mirroring operation according to embodiments of the inventive concept; 
         FIG. 10  is a flowchart illustrating an exemplary bidirectional display mirroring method carried out by the first user device according to according to an embodiment of the inventive concept; 
         FIG. 11  is a flowchart illustrating an exemplary bidirectional display mirroring method carried out by the second user device according to an embodiment of the inventive concept; 
         FIGS. 12A  and  FIG. 12B  are flowcharts illustrating an exemplary data streaming/downloading method carried out by the first user device according to embodiments of the inventive concept; and 
         FIG. 13  is a flowchart illustrating an exemplary data streaming/downloading method carried out by the second user device according to an embodiment of the inventive concept. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Reference will now be made in detail to the embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present general inventive concept by referring to the figures. In the following description, exemplary circuit structures and operations of user devices are described, and the user devices may be changed or modified within the scope of the inventive concept. For example, in the following description of the inventive concept, an explanation is given on exemplary user devices that can compress/decompress and display digital multimedia contents such as video, graphic, and audio data transmitted through a wireless network. 
     During a wireless data sharing or display mirroring operation of a wireless sharing system of the inventive concept, compressed source files stored in a transmitting user device can be directly transmitted to a receiving user device before the compressed source files are decoded. That is, during the wireless data sharing or display mirroring operation, the transmitting user device (for example, a portable electric device) is not necessary to decode the compressed source files and transcode display data which are results of decoding, and the receiving user device is not necessary to decode transcoded data received from the transmitting user device. Therefore, the display mirroring operation and wireless sharing operation for sharing source files may be efficiently carried out without a time delay under limiting conditions such as the data transmission rate and bandwidth of a wireless network and power consumption limitation. In addition, display mirroring and wireless data sharing of multimedia contents may be possible without deterioration of image quality caused by the resolution of the other device. The inventive concept is not limited to the above-described examples. That is, the inventive concept may be applied to various user devices, and the wireless sharing method and display mirroring method of the inventive concept are not limited to particular user devices but may be applied to various user devices. 
       FIG. 1  is a view illustrating an exemplary structure of a wireless data sharing system according to an embodiment of the inventive concept. 
     Referring to  FIG. 1 , user devices may include a portable electric device (hereinafter referred to as a first user device  1000 ) such as a cellular phone, a smart phone, a personal digital assistant (PDA), a portable multimedia player (PMP), a digital camera, a camcorder, a voice recorder, an MP3 player, and a game unit, and an audio/video (NV) device (hereinafter referred to as a second user device  2000 ) capable of displaying TV images through a large display and reproducing multichannel audio data. In addition, the user devices may further include a third user device  3000  such as a personal computer (PC), a digital camera, a printer, and a storage medium connectable to the PC. It is possible that the first user devise  1000  may be same as at least one of the second user device  2000  and the third user device  3000 , and it is also possible that the first user device  1000  is different from the second user device  2000  and the third user device  3000 . The above-mentioned user devices are exemplary user devices to which the inventive concept can be applied. That is, various user devices may be used. The user devices, and the wireless sharing method and display mirroring method of the inventive concept are not limited to particular devices. 
     The user devices  1000 ,  2000 , and  3000  may transmit and receive multimedia data by wireless communication. In some embodiments, the user devices  1000 ,  2000 , and  3000  may be connected to each other by small-size, low-power-consumption, and inexpensive wireless personal area network (WPAN) technology. The WPAN technology may include ZigBee, Bluetooth, and ultra-wideband (UWB) based wireless universal serial bus (WUSB) technologies. These technologies are exemplary technologies to which the inventive concept may be applied. That is, the inventive concept may be applied to various radio transmission technologies. 
       FIG. 2  is a view illustrating frequency characteristics of WUSB that can be used for display mirroring according to an embodiment of the inventive concept. 
     Referring to  FIG. 2 , UWB on which WUSB is based may be defined as radio transmission technology having a spectrum that occupies a bandwidth greater than 20 percent of the center frequency, or a bandwidth of at least 500 MHz. The most distinguished features of USB are the use of an ultra wideband and relatively low output power. That is, as shown in  FIG. 2 , a UWB system may be configured based on a very low spectrum power density over an extremely broad bandwidth as compared with a narrowband system or a wideband code division multiple access (CDMA) system. A UWB system can send a signal by spreading the signal over several GHz of bandwidth to prevent interference with signals of other communication systems. Therefore, a UWB system can carry out communications with less frequency limitation and low power consumption without causing interference with other narrowband signals. 
     Since UWB is more advantageous than wireless local area network (WLAN) and Bluetooth in features such as high transmission rate and low power consumption, UWB draws attention as communication technology between high-performance portable devices. Particularly, the low power consumption feature of UWB may be useful to solve the battery capacity problem of portable devices. In addition, the high transmission rate of UWB reaching several hundreds of Mbps may be considered as the most important merit of UWB because it allows smooth transmission of almost all kinds of data such as high-quality image data. However, due to low output power of UWB, UWB may be suitable as a service solution using WPAN rather than a service solution using a public network. 
     In the following description of the inventive concept, explanations will be given on examples of wireless data sharing and display mirroring that use UWB based WUSB among various wireless network technologies. However, these are only examples of the inventive concept. That is, the inventive concept is not limited to a particular wireless network but may be applied to various wireless networks. Devices communicating with each other through the wireless network and a wireless communication may have units to perform the networking and communicating operations between the devices. Since the units to perform the networking and communicating operations are well known, and also a wireless network and a wireless communication are well known, detail descriptions thereof will be omitted. 
     The wireless sharing system of the inventive concept may include the different kinds of user devices  1000 ,  2000 , and  3000  as shown in  FIG. 1 . According to the inventive concept, wireless data sharing and display mirroring operations may be carried out among the different kinds of user devices  1000 ,  2000 , and  3000  unidirectionally or bidirectionally. 
     For example, during a display mirroring operation, the first user device  1000  (such as a portable electric device) including a small display may operate as a transmitting user device, and the second user device  2000  including a display of equal or greater size may operate as a receiving user device. In this disclosure, this will be referred to as a first type display mirroring operation. In the first type display mirroring operation, a screen which is being displayed on the first user device  1000  may be shared with the second user device  2000  by wireless connection so that the same screen can be displayed on the first and second user devices  1000  and  2000 . 
     In a display mirroring operation of the inventive concept, the second user device  2000  which is operating as a receiving user device can be changed to a transmitting user device in response to a user&#39;s request or manipulation, and the first user device  1000  which is operating as a transmitting user device can be changed to a receiving user device. In this disclosure, this will be referred to as a second type display mirroring operation. In the second type display mirroring operation, a multimedia source stored in the second user device  2000  or a screen which is being displayed on the second user device  2000  may be shared with the first user device  1000  by wireless connection so that the same screen can be displayed on the first and second user devices  1000  and  2000 . 
     In the wireless data sharing operation and display mirroring operation of the inventive concept, compressed source files stored in a transmitting user device can be directly transmitted to a receiving user device before the transmitting user device decodes the compressed source files to display the source files (this will be described later in more detail). This source file transmission operation may be carried by WUSB based on UWB. 
     Since UWB is much more advantageous than WLAN or Bluetooth in features such as high transmission rate and low power consumption, it may take very short time to transmit source files from the first user device  1000  to the second user device  2000 . Therefore, transmitting user device and receiving user device may decode compressed source files almost at the same time, and thus display mirroring may be performed without a time delay. 
     Instead of transmitting compressed source files directly from a transmitting user device, data of a screen which is being displayed on the transmitting user device (that is, data obtained by decoding compressed source files) may be transmitted to a receiving user device so as to perform a display mirroring operation. In this case, however, since the screen which is being displayed on the transmitting user device is a result obtained by decoding the source files, more data have to be transmitted. Therefore, to transmit decoded source files by wireless, the decoded source files may have to be compressed again by using a certain compression format according to a bandwidth and a transmission rate. Such an additional compressing operation for transmitting data of a display screen is called “transcoding.” 
     In a display mirroring method based on transcoding, a transmitting user device decodes compressed source files and performs a transcoding operation to compress the decoded compressed source files again. Then, a receiving user device has to decode the transcoded data received from the transmitting user device. However, according to the inventive concept, since compressed source files are directly transmitted to a receiving user device before the compressed source files are decoded, an additional transcoding operation is unnecessary. 
     In an exemplary embodiment, compressed source files stored in a transmitting user device may be decoded after the compressed source files are transmitted by wireless from the transmitting user device to a receiving user device. In another exemplary embodiment, compressed source files stored in a transmitting user device may be decoded while the compressed source files are being transmitted by wireless from the transmitting user device to a receiving user device. Decoding of compressed source files stored in a transmitting user device, and wireless transmission of the source files from the transmitting user device to a receiving user device are not limited to the orders explained in the above embodiments but may be carried out in different orders or manners. 
     According to the above-described configurations of the inventive concept, during wireless data sharing and display mirroring operations, before compressed source files stored in a transmitting user device are decoded, the compressed source files can be directly transmitted to a receiving user device without having to perform an additional transcoding operation. Therefore, display mirroring and wireless sharing of the source files can be effectively performed without a time delay even under limiting conditions such as the data transmission rate and bandwidth of a wireless network and power consumption limitation. In addition, since user devices can decode source files individually according to their display resolutions, decoded data can be properly displayed on the user devices according to the resolutions of the user devices without deterioration of image quality. 
       FIG. 3  is a view illustrating exemplary overall structures of the first and second user devices  1000  and  2000  illustrated in  FIG. 1 . 
     Referring to  FIG. 3 , the first and second user devices  1000  and  2000  may be different kinds of devices. In the example shown in  FIG. 3 , the first user device  1000  is a portable electric device such as a cellular phone, a smart phone, a personal digital assistant (PDA), a portable multimedia player (PMP), a digital camera, a camcorder, a voice recorder, an MP3 player, and a game unit, and the second user device  2000  is an audio/video (NV) device supporting TV image transmission and multichannel audio data. In this case, the second user device  2000  may be a non-portable device and include a large display (hereinafter referred to as a second display  290 ). On the other hand, the first user device  1000  may include a display (hereinafter referred to as a first display  190 ) smaller than the second display  290 . The first and second displays  190  and  290  may be different kinds of displays having different operational characteristics. Examples of the first and second displays include a liquid crystal display (LCD), a plasma display panel (PDP), an electro luminescent display (ELD), a light emitting diode (LED) display, a vacuum fluorescent display (VFD), and a touch screen. Due to different sizes, kinds, and operational characteristics of the first and second displays  190  and  290 , the first and second displays  190  and  290  may have different resolutions. 
     In the case where the second user device  2000  is a non-portable device, the second user device  2000  may use AC power as main power. On the other hand, the first user device  1000  which is a portable electric device may use a battery as a main power supply. Detailed structures of the first and second user devices  1000  and  2000  are as follows. 
     The first user device  1000  may include a first RF transceiver (first signal transceiver)  110 , a first main storage  130 , a first controller (or first CPU)  150 , and a first display  190 , and a first input unit (or first selection unit)  195 . 
     The first main storage  130  may include a nonvolatile memory such as a flash memory to store various source files such as audio/video/graphic files and display information of the source files. In an exemplary embodiment, audio/video/graphic files may be stored in the first main storage  130  after being compressed by a predetermined method. Display information of the audio/video/graphic files may be stored in the form of metadata. 
     For example, video files may be compressed by a format such as Moving Picture Export Group (MPEG), Real Video, Motion-JPEG (AVI), Advanced Streaming Format (ASF), and H.264. Graphic files may be compressed by a format such as PSD, PCX, PDF, TIFF (TIF), GIF, TGA, PICT, EPS, JPEG, PNG (Portable Network Graphics), and WMF (Window Meta File). Audio files may be compressed by a format such as MP3, WAV (Waveform-Audio Format), APE, OGG, AAC (Advanced Audio Coding), and FLAC (Free Lossless Audio Codec). Display information of audio/video/graphic files may be stored in the form of metadata. In addition, source files stored in the first main storage  130  may include text files. The various kinds (or formats) of source files that can be stored in the first main storage  130  and compressing methods of the source files are not limited to particular kinds or methods but can be varied. The first main storage  130  may be configured by a hard disk drive (HDD) or semiconductor memory chips to store source files. 
     In the current embodiment, the first main storage  130  is configured by a flash memory (semiconductor chip) which is a nonvolatile memory. However, the kind of a memory and operational characteristics of the memory that can be used to constitute the first main storage  130  are not limited to particular kinds or characteristics but can be varied. For example, as well as a flash memory, a nonvolatile memory such as MRAM and PRAM may be used to constitute the first main storage  130 . In addition, examples of memories that can be used to constitute the first main storage  130  include volatile memories such as DRAM. For example, the first main storage  130  may be constituted by at least one nonvolatile memory and at least one volatile memory, or at least two kinds of nonvolatile memories. 
     The number of data bits that can be stored in each memory cell of the first main storage  130  may be varied. For example, one bit may be stored in each cell of the flash memory, or a plurality of bits may be stored in each cell of the flash memory. A memory cell in which one bit is stored is called a single-bit cell or single-level cell (SLC). A memory cell in which a plurality of bits are stored is called a multi-bit cell, multi-level cell (MLC), or multi-state cell. 
     The flash memory may include various kinds or types of memory cells. For example, the flash memory may be a NAND flash memory or NOR flash memory, and a flash memory core and a memory controller may be included in a single chip. The flash memory may be a hybrid type flash memory in which at least two kinds of flash memories are combined. 
     Charge storage layers of flash memory cells may have various structures. For example, the charge storage layers of the flash memory cells may be constituted by conductive floating gates. The charge storage layers may be constituted by Si 3 N 4 , Al 2 O 3 , HfAlO, or HfSiO films. Particularly, the charge storage layers may be constituted by films that can have charge trap sites. A flash memory including such films as charge trap layers is called a charge trap flash (CTF) memory. 
     The first CPU  150  may control operations of the first user device  1000 . In an exemplary embodiment, the first CPU  150  may be a commercially available or custom-made microprocessor. The first CPU  150  may include a decoder to decode compressed audio/video/graphic files stored in the first main storage  130  or provided from an outside device (for example, the second user device  2000  or internet service provider (ISP)). A decoding result of the first CPU  150  may be displayed on the first display  190 . 
     In a first type display mirroring (or sharing) operation, the first user device  1000  may transmit source files (i.e., audio/video/graphic files and display information of the audio/video/graphic files) stored in the first main storage  130  directly to the second user device  2000  through the first RF transceiver  110  before the force files are decoded. In an exemplary embodiment, the first RF transceiver  110  may transmit and receive data by wireless according to UWB based WUSB. 
     Furthermore, in a second type display mirroring (or sharing) operation, the first RF transceiver  110  may receive source files from the second user device  2000  and transfer the received source files to the first CPU  150 . The first CPU  150  may decode the source files provided from the second user device  2000  by using its decoder, and the decoding result may be displayed on the first display  190 . 
     The first input unit (first selection unit)  195  may be connected to the first CPU  150  through wired or wireless communications. The first input unit  195  may generate signals or commands to select one of the source files to be decoded or transmitted to an external device or to select one of external devices for transmitting or receiving of the source files. The first input unit  195  may be implemented as a touch screen of the display  190  to perform the input function or selection function. 
     The first CPU  150  may generate a list of source files and control the display  190  to display a menu and/or a list of source files such that a user can select one of the source files using the first input unit  195 . The first RF transceiver  110  may receive a list of source files stored in the second user device  2000 , and the list of the source files can be displayed on the screen of the display  190  such that a user can select one of the displayed source files using the input unit  195 . 
     The first CPU  150  may generate a list of one or more external devices including the second user device  2000  or the third user device  3000  and controls the display  190  to display the list such that a user can select one of the external devices using the first input unit  195 . In this case, the source file and an ID of the selected device can be transmitted to the second user device  2000 , and the second user device  2000  can recognize the ID to receive, store, and/or decode the transmitted source file to be displayed on a screen thereof. 
     When a source file is selected without designating or selecting a particular external device, the selected source file can be transmitted to any one of one or more external devices through the RF transceiver  110  such that a user of the respective external device can determine whether to receive, store, and/or decode the transmitted source file from the first user device  1000 . 
     The first main storage  130  may include additional memory spaces or additional memory unit to store source files or data input from the first input unit  195  or received from the second user device  2000  through the first RF transceiver  110 . 
     The first input unit  195  can select one of the first type display mirroring (or sharing) operation and the second type display mirroring (or sharing) operation. The first CPU  150  may generate a menu or a list of the operations and control the display  190  to display the menu or the list such that a user can select the one of the first type display mirroring (or sharing) operation and the second type display mirroring (or sharing) operation through the displayed menu or list on a screen of the display  190 . When the first type display mirroring operation is selected, the source file is decoded and also transmitted to the second user device  2000 . When the second type display mirroring operation is selected, a signal corresponding to the second type display mirroring operation is transmitted to the second user device  2000  such that a menu or list of source files stored in the second user device  2000  can be transmitted to the first user device  1000 . The first user device  1000  displays the received menu or list on a screen of the display  190  such that selection of the source files is performed, and transmission of the selected source file is transmitted from the second user device  2000  to the first user device  1000 . 
     The first RF transceiver  110 , the first controller  150 , and the decoding unit may be included in a single integrated chip. The first user device  1000  may further include a housing to accommodate the single integrated chip. The housing of the first user device  1000  may accommodate the main storage  130 , the display  190 , and/or the buffer  140  therein or thereon. 
     The second user device  2000  may include a second RF transceiver (or second signal transceiver)  210 , a second main storage  230 , a second controller (or second CPU)  250 , a video/graphic processor  270 , a second display  290 , and a second input unit (or second selection unit)  295 . 
     Like the first main storage  130  of the first user device  1000 , the second main storage  230  may include a nonvolatile memory such as a flash memory. Various source files, such as audio/video/graphic files and text files, may be stored in the second main storage  230  after being compressed by a predetermined format, and display information of the source files may be stored in the second main storage  230  in the form of metadata. 
     In a first type display mirroring operation, the second RF transceiver  210  may receive audio/video/graphic files from the first user device  1000 , and in a second type display mirroring operation, source files to be displayed on the second user device  2000  may be transmitted to the first user device  1000  through the second RF transceiver  210 . In an exemplary embodiment, the second RF transceiver  210  may transmit and receive data by wireless according to UWB based WUSB. 
     The second CPU  250  may control operations of the second user device  2000 . The video/graphic processor  270  may connected to the second CPU  250 . In a first type display mirroring operation, the video/graphic processor  270  may decode source files received from the first user device  1000  or an outside device (through a wired/wireless network or an internet service provider (ISP)). In the second type display mirroring operation, compressed source files and display information of the source files stored in the second main storage  230  may be transmitted to the first user device  1000  through the second RF transceiver  210  before the source files are decoded by the video/graphic processor  270 . 
     The second input unit (or second selection unit)  295  may be connected to the second CPU  250  through wired or wireless communications. The second input unit  295  may generate signals or commands to select one of the source files to be decoded or transmitted to an external device or to select one of external devices for transmitting or receiving of the source files. The second input unit  295  may be implemented as a touch screen of the display  290  to perform the input function or selection function. 
     The second CPU  250  may generate a list of source files and control the display  290  to display a menu and/or a list of source files such that a user can select one of the source files using the second input unit  295 . The second RF transceiver  210  may receive a list of source files stored in the first user device  1000 , and the list of the source files can be displayed on the screen of the display  290  such that a user can select one of the displayed source files using the second input unit  195   
     The second CPU  250  may generate a list of one or more external devices including the first user device  1000  or the third user device  3000  and controls the display  290  to display the list such that a user can select one of the external devices using the second input unit  295 . In this case, the source file and an ID of the selected device can be transmitted to the first user device  1000 , and the first user device  1000  can recognize the ID to receive, store, and/or decode the transmitted source file to be displayed on a screen thereof. 
     When a source file is selected without designating or selecting a particular external device, the selected source file can be transmitted to any one of one or more external devices through the RF transceiver  210  such that a user of the respective external device can determine whether to receive, store, and/or decode the transmitted source file from the second user device  2000 . 
     The second main storage  230  may include additional memory spaces or additional memory unit to store source files or data input from the second input unit  295  or received from the first user device  1000  through the second RF transceiver  210 . 
     The second input unit  195  can select one of the first type display mirroring (or sharing) operation and the second type display mirroring (or sharing) operation. The second CPU  250  may generate a menu or a list of the operations and control the display  290  to display the menu or the list such that a user can select the one of the first type display mirroring (or sharing) operation and the second type display mirroring (or sharing) operation through the displayed menu or list on a screen of the display  290 . When the first type display mirroring operation is selected, the source file is decoded and also transmitted to the second user device  1000 . When the second type display mirroring operation is selected, a signal corresponding to the second type display mirroring operation is transmitted to the first user device  1000  such that a menu or list of source files stored in the first user device  1000  can be transmitted to the second user device  2000 . The second user device  2000  displays the received menu or list on a screen of the display  290  such that selection of the source files is performed, and transmission of the selected source file is transmitted from the first user device  1000  to the second user device  2000 . 
     The second RF transceiver  210 , the second controller  250 , and the decoding unit may be included in a single integrated chip. The second user device  2000  may further include a housing to accommodate the single integrated chip. The housing of the second user device  2000  may accommodate the main storage  230 , the display  290 , and/or buffer  240  therein or thereon. 
     In the above description, a display mirroring operation among a plurality of user devices ( 1000 ,  2000 ) has been explained as an example of wireless data sharing. However, the display mirroring operation is merely an example of the inventive concept. That is, the wireless data sharing of the inventive concept can be applied to other operations such as a wireless data downloading operation and a wireless data streaming operation as well as the display mirroring operation. In addition, the inventive concept can be applied to other type of data such as text files as well as source files such as audio/video/graphic files. 
     The first user device  1000  or the second user device  2000  may include a user interface to communicate with another interface of another one of the first user device  1000  and the second user device  2000  to perform wired or wireless communications, for example, a telephone function, an Internet function, a text function, etc., other than the above describe operations. However, the present general inventive concept is not limited thereto. The above-described operations and functions can be performed a single interface or a signal transceiver. 
     The first user device  1000  and the second user device  2000  may recognize the data corresponding to the source file by using a particular signal included in the data or by a selecting or requesting operation of selecting or requesting the source file to be transmitted. Therefore, when the source file is selected or requested, the first user device  1000  and the second user device  2000  can recognize the source file to be transmitted between the first user device  1000  and the second user device  2000  so that the first user device  1000  and the second user device  2000  can transmit, receive, store, and/or decode the data (or signal) of the source file. It is possible that the data of the source file may include the particular signal indicating the source file to be transmitted between the first user device  1000  and the second user device  2000 . Using the particular signal, the first user device  1000  and the second user device  2000  can transmit, receive, store, and/or decode the data (or signal) of the source file. 
       FIGS. 4 through 6  are views illustrating a first type display mirroring operation according to embodiments of the inventive concept. 
       FIG. 4  illustrates data transmitting and receiving processes during a first type display mirroring operation according to an embodiment of the inventive concept.  FIG. 5  illustrates a detailed structure of a first user device  1000  configured to perform a first type display mirroring operation according to an embodiment of the inventive concept.  FIG. 6  illustrates a detailed structure of a second user device  2000  configured to perform a first type display mirroring operation according to an embodiment of the inventive concept. 
     Referring to  FIG. 5 , the first user device  1000  may include a first RF transceiver  110 , a first RF interface  120 , a first main storage  130 , a first buffer  140 , a first CPU  150 , a decoder  170 , a first display interface  180 , and a first display  190 . The first RF transceiver  110 , the first main storage  130 , the first CPU  150 , and the first display  190  may have the same structures as those illustrated in  FIG. 3 . Thus, descriptions thereof will not be repeated. 
     Referring to  FIGS. 4 and 5 , if a user requests mirroring during a first type display mirroring operation, compressed audio/video/graphic files and display information stored in the first main storage  130  of the first user device  1000  may be provided to the first CPU  150  (S 1000 ) and the first RF transceiver  110  through the first RF interface  120  (S 1100 ). 
     The first RF interface  120  may be connected between the first RF transceiver  110  and the first main storage  130 . The first RF interface  120  may multiplex the compressed audio/video/graphic files and display information stored in the first main storage  130  and provide the multiplexing result to the first RF transceiver  110 . The first RF interface  120  is not limited to a particular multiplexing method. That is, the first RF interface  120  may use various multiplexing methods. The multiplexing result provided from the first RF interface  120  to the first RF transceiver  110  may be transmitted to the second user device  2000  by wireless through a wireless network such as WUSB (S 1200 ). The first RF transceiver  110  may include the RF interface  120  to form a single unit. In an exemplary embodiment, the audio/video/graphic files to be displayed on the first user device  1000  may be provided to the second user device  2000  through the first RF transceiver  110  before or while the audio/video/graphic files are decoded by the first CPU  150 . 
     After or while the compressed audio/video/graphic files and display information are transmitted by a wireless communication through the first RF transceiver  110 , the first CPU  150  may decode the compressed audio/video/graphic files. Then, under the control of the first CPU  150 , the decoding result may be displayed on the first display  190  based on the display information in operation S 1300 . For this, the first CPU  150  may include the decoder  170  that can decode audio/video/graphic files compressed by predetermined formats. A decoding result of the decoder  170  may be stored in the first buffer  140 . 
     The first buffer  140  may store data temporarily while the data are transmitted between the first CPU  150  and the first display interface  180 . The data may include the result of decoding of the audio/video/graphic files and the display information of the audio/video/graphic files. The first buffer  140  may include a random access memory such as a DRAM or SRAM. In the current embodiment, the first buffer  140  includes a DRAM. 
     The first display interface  180  may provide the audio/video/graphic files decoded by the decoder  170  and the display information of the audio/video/graphic files to the first display  190 . The first display  190  may display the data provided from the first display interface  180  on a screen. 
     The first display interface  180  may include an LCD interface, a high-definition multimedia interface (HDMI), and a DisplayPort. HDMI is one of high-definition digital TV interface standards that can be included in various user devices such as a smart phone, a camcorder, and a digital camera. DisplayPort is a recent digital display interface standard. DisplayPort makes it possible to easily output HD audio data and HD video data and supports connection to various PCs as well as connection to a USB HUB and a webcam. 
     Although not shown in  FIG. 5 , the first user device  1000  may further include a general-purpose interface such as USB and PCI express (PCIe). The wireless sharing method of the inventive concept may be applied to other operations such as a streaming operation or a downloading operation for a device connected through the general-purpose interface as well as a display mirroring operation for the first display  190  connected through the first display interface  180 . 
     In the case where the first user device  1000  is a portable electric device, the first RF transceiver  110 , the first RF interface (I/F)  120 , the first CPU  150 , the decoder  170 , and the first display interface  180  may be integrated into a single chip or a system on chip (SOC). In this case, the size of the first user device  1000  can be reduced owing to the integration. 
     As illustrated in  FIG. 5 , the SOC may be a circuit board with components, for example, the first RF transceiver  110 , the first RF interface  120 , the first CPU  150 , the decoder  170 , and/or the first display interface  180  which are electrically connected through a circuit thereof. The SOC may have a plurality of terminals T 1 , T 2 , T 3 , T 4 , and/or T 5 , for example, formed thereon. The SOC may be a signal unit, an integrated unit, or a monolithic device which is formed with the above described terminals. The first main storage  130  is connected to the terminal T 1  of the SOC. The terminal T 1  of the SOC may be a common terminal through which data or signal, for example, the source file, can be transmitted from the first main storage  130  to both the first CPU  150  and the RF I/F  120 . The data or signals, for example, a source file received from the second user device  2000  can be transmitted to the first main storage  130  through the common terminal T 1 . 
     The terminals T 2  and T 3  can be used to connect the SOC and the buffer  140 . The terminal T 4  can be used to connect the SOC and the display  190 . The terminal T 5  can be used to connect the SOC and the first input unit  195 . When the first input  195  is formed with the display  190 , the terminal T 4  can be used to connect the SOC and both the display  190  and the first input unit  195 . In this case, the terminal T 5  can be omitted. However, the present general inventive concept is not limited thereto. The terminal T 5  can be used to connect the SOC and other component or device to receive data or signals to control the first CPU  150 . It is also possible that the terminal T 5  is used as an interface terminal to connect the SOC and an interface to provide wired or wireless communication between the first CPU  150  and external device. It is possible that the buffer  140  may be installed on the SOC. In this case, the terminals T 2  and T 3  may not be used. 
     Since the SOC includes the common terminal T 1 , a conductive signal line may have a first line connected to the common terminal T 1 , and second lines extended from the first line to each of the first CPU  150  and the RF I/F  120 . Therefore, the source file can be read from the first main storage  130  and then distributed to the first CPU  150  and the RF I/F  120 . In this case, the SOC may not require two terminals to connect the main storage  130  to the first CPU  150  and the RF I/F  120 . 
     It is possible that a conductive line includes a first line connected to the main storage  130  and second lines extended from the first line and connected to two terminals (two of T 1 ), for example, T 11  and T 12 , formed on the SOC. In this case the two terminals (two of T 1 ), for example, T 11  and T 12 , are connected to the first CPU  150  and the RF I/F  120 , respectively. Accordingly, data or signals, for example, the source file, is read from the first main storage  130  and then distributed to each of the first CPU  150  and the RF I/F  120  such that the source file can be simultaneously decoded and transmitted. The source file can be transmitted through the RF transceiver  110  without being decoded. 
     The antenna may be connected to the SOC through a terminal connected to the first RF transceiver  110 . However, it is possible that the antenna can be installed on the SOC. 
     Referring to  FIGS. 4 and 6 , the compressed audio/video/graphic files and the display information transmitted by wireless through the first RF transceiver  110  may be provided to the second user device  2000  through a second RF transceiver  210 . 
     The second user device  2000  may include the second RF transceiver  210 , a second RF interface  220 , a second main storage  230  (refer to  FIGS. 3 and 8 ), a second buffer  240 , a second CPU  250 , a video/graphic processor  270 , a second display interface  280 , and a second display  290 . The second RF transceiver  210 , the second main storage  230 , the second CPU  250 , the video/graphic processor  270 , and the second display  290  may have the same structures as those shown in  FIG. 3 . Thus, descriptions thereof will not be repeated. 
     The compressed audio/video/graphic files and the display information received through the second RF transceiver  210  may be provided to the second RF interface  220  and may be demultiplexed. The demultiplexing result of the second RF interface  220  may be provided to the video/graphic processor  270  in operation S 1400 . 
     The video/graphic processor  270  may decode the compressed audio/video/graphic files under the control of the second CPU  250 . The decoding result of the video/graphic processor  270  and the display information may be temporarily stored in the second buffer  240 . The second buffer  240  may include a random access memory. In the current embodiment, the second buffer  240  includes a DRAM. 
     The decoding result and the display information stored in the second buffer  240  may be provided to the second display  290  through the second display interface  280  in operation S 1500 . The second display interface  280  may include an LCD interface, a high-definition multimedia interface (HDMI), and a DisplayPort. The second display  290  may display data received through the second display interface  280  on a screen. The second display  290  may include an LCD or a touch screen. The second display interface  280  and the second display  290  are not limited to particular structures but may have various structures. 
     Although not shown in  FIG. 6 , the second user device  2000  may further include a general-purpose interface such as USB and PCIe, and a large-capacity storage such as a HDD. The wireless sharing method of the inventive concept may be applied to other operations such as a streaming operation or a downloading operation for a device connected through the general-purpose interface as well as a display mirroring operation. The general-purpose interface may include a wired/wireless transceiver such as a wired/wireless LAN interface. 
     The second user device  2000  may perform a wireless data sharing operation for source files provided by an internet service provider (ISP) as well as for source files received by wireless from the first user device  1000 . That is, the second user device  2000  may perform a wireless data sharing operation for various kinds of source files and source providers. 
     As described above, in a first type display mirroring operation of the inventive concept, compressed source files to be displayed on the first user device  1000  may be transmitted to the second user device  2000  before the compressed source files are decoded at the first user device  1000 . Then, a decoding operation of the first user device  1000  for the compressed source files to be displayed on the first user device  1000  may be performed in parallel with or substantially at the same time with a decoding operation of the second user device  2000  for the compressed source files received from the first user device  1000 . Therefore, a wireless data sharing operation such as the display mirroring operation can be performed without a time delay. 
     In the inventive concept, the first and second displays  190  and  290  of the first and second user devices  1000  and  2000  may have different resolutions. For example, the resolution of the second display  290  which is a large display may be higher than that of the first display  190  which is a small display. 
     If a first type display mirroring operation is performed based on transcoding as described above, the resolution of a screen mirrored to the second user device  2000  is determined by the resolution of the first display  190 . In this case, although the resolution of the second display  290  is higher than the resolution of the first display  190 , the second display  290  displays the screen with a resolution determined by the resolution of the first display  190 . 
     However, in a first type display mirroring operation of the inventive concept, transcoding is not performed, and thus the second user device  2000  can carry out decoding according to the resolution of the second display  290  regardless of the resolution of the first display  190 . Therefore, according to the first type display mirroring method of the inventive concept, a high-quality display screen can be provided to users without image degradation. These display characteristics of the inventive concept may be the same in a second type display mirroring operation and a first type display mirroring operation. 
     When the source file is selected according to a selection unit or an input unit, the selected source file is transmitted to the first CPU  150  and the first RF transceiver  110  such that the first CPU  150  decodes the source file upon receiving, and the first RF transceiver  110  transmits the source file to an external apparatus or device upon receiving without a decoding process. 
     When the source file is transmitted from the first storage  130  to the first CPU  150  and then decoded to be displayed on a screen of the display  190 , the source file can be selected to be transmitted to an external apparatus or device. In this case, a first portion of the source file has been already transmitted to the first CPU  150  and then decoded to be displayed on a screen of the display  190 . Accordingly, a second portion (remaining portion) of the source file is read from the main storage  1130  and then transmitted to both the first CPU  150  and the first RF transceiver  110  such that the first CPU decodes the second portion of the source file to be displayed on a screen of the display  190  and the first RF transceiver  110  transmits the second portion of the source file to the external apparatus or device. In this case, the external apparatus, for example, the second user device  2000  receives the second portion of the source file and decodes the second portion of the source file to be displayed on a screen of the display  290 . 
     When the source file stored in the second user device  2000  is transmitted from the second user device  2000  to the first user device  1000 , and decoded in both the second user device  2000  and the first user device  1000  to be simultaneously displayed on the screens thereof, another source file stored in the first user device  1000  can be selected or determined to transmit to both the first CPU and the first RF transceiver  110 . In this case, the another source file can be decoded in the first CPU  150  and also transmitted to the second user device  2000  through the first RF transceiver  110  and the second RF transceiver  210 . 
       FIGS. 7 through 9  are views illustrating a second type display mirroring operation according to embodiments of the inventive concept. 
       FIG. 7  illustrates data transmitting and receiving processes during a second type display mirroring operation according to an embodiment of the inventive concept.  FIG. 8  illustrates a detailed structure of a second user device  2000  configured to perform a second type display mirroring operation according to an embodiment of the inventive concept.  FIG. 9  illustrates a detailed structure of a first user device  1000  configured to perform a second type display mirroring operation according to an embodiment of the inventive concept. 
     According to the inventive concept, a display mirroring operation can be bidirectionally performed. For example, the second user device  2000  operating as a receiving user device in a first type display mirroring operation may start to operate as a transmitting user device if a user requests a second type display mirroring operation. 
     Referring to  FIGS. 7 and 8 , if a user requests a second type display mirroring operation, the second user device  2000  provides source files (compressed audio/video/graphic files and display information) stored in a second main storage  230  to a second RF transceiver  210  through a second RF interface  220  in operation S 2000  and to a video/graphic processor  270  in operation S 2100  under the control of a second CPU  250 . The compressed audio/video/graphic files and display information provided to the second RF transceiver  210  may be transmitted to the first user device  1000  through a wireless network such as WUSB in operation S 2200 . 
     After or while the compressed audio/video/graphic files and display information are transmitted to the first user device  1000  through the second RF transceiver  210 , the video/graphic processor  270  may decode the compressed audio/video/graphic files. The decoding result of the video/graphic processor  270  may be displayed on the second display  290  through the second display interface  280  in operation S 2300 . 
     Referring to  FIGS. 7 and 9 , the compressed audio/video/graphic files and display information transmitted through the second RF transceiver  210  may be received by the first user device  1000  through a first RF transceiver  110  of the first user device  1000 . The compressed audio/video/graphic files and display information may be provided to a first CPU  150  through a first RF interface  120  in operation S 2400 . 
     The first CPU  150  may include a decoder  170  to decode the compressed audio/video/graphic files. The first CPU  150  may create a screen based on the decoding result of the decoder  170  and the display information, and then the first CPU  150  may display the screen on a first display  190  through a first display interface  180  in operation S 2500 . 
     As described above, in a second type display mirroring operation of the inventive concept, the second user device  2000  which operates as a receiving user device in a first type display mirroring operation can be changed to operated as a transmitting user device, and the first user device  1000  which operates as a transmitting user device in a first type display mirroring operation can be changed to operated as a receiving user device. 
     Furthermore, in a second type display mirroring operation of the inventive concept, source files to be displayed on the second user device  2000  can be transmitted to the first user device  1000  before the source files are decoded at the second user device  2000 . Then, a decoding operation of the second user device  2000  for the source files may be performed in parallel with or substantially at the same time with a decoding operation of the first user device  1000  for the source files. Therefore, a wireless data sharing operation, such as the display mirroring operation, can be performed without a time delay. In this case, the first user device  1000  and the second user device  2000  can perform decoding operations according to their own resolutions regardless of the resolution of the other user device. Therefore, according to the first type display mirroring method of the inventive concept, high-quality display images can be provided to users without image degradation. 
       FIG. 10  is a flowchart illustrating an exemplary bidirectional display mirroring method carried out by the first user device  1000  according to according to an embodiment of the inventive concept. 
     Referring to  FIG. 10 , the first user device  1000  determines whether there is a display mirroring request from a user in operation S 3000 . If it is determined that there is a display mirroring request from a user in operation S 3000 , it is determined whether the display mirroring request is for a first type display mirroring operation or a second type display mirroring operation in operation S 3100 . 
     When it is determined that the display mirroring request is for a first type display mirroring operation in operation S 3100 , the first user device  1000  may decode compressed source files stored in the first main storage  130  in operation S 3200 , and in parallel with this, the first user device  1000  may transmit the compressed source files (e.g., audio/video/graphic files) and corresponding display information to the second user device  2000  by a wireless communication in operation S 3300 . In the first type display mirroring operation, the first user device  1000  operates as a transmitting user device, and the second user device  2000  operates as a receiving user device. 
     In an exemplary embodiment, decoding in operation S 3200  and wireless transmitting in operation S 3300  of the first user device  1000  may be simultaneously performed. In another example, decoding in operation S 3200  may be performed after wireless transmitting in operation S 3300 . In the current embodiment of the inventive concept, wireless transmitting of the source files may be performed by UWB based WUSB that allows a high transmission rate of several hundreds of Mbps. In this case, since it takes very short time to transmit the source files from the first user device  1000  to the second user device  2000  by a wireless communication, decoding operations of the first and second user devices  1000  and  2000  may be performed substantially at the same time. The source files decoded by the first user device  1000  are displayed on the first display  190  of the first user device  1000  based on the corresponding display information in parallel with a displaying operation of the second user device  2000  in operation S 3400 . 
     When the display mirroring request is for a second type display mirroring operation in operation S 3100 , the first user device  1000  interrupts its current operation in operation S 3500  and receives source files and display information of the source files transmitted by wireless from the second user device  2000  in operation S 3600 . In the second type display mirroring operation, the first user device  1000  operates as a receiving user device, and the second user device  2000  operates as a transmitting user device. The first user device  1000  decodes the received source files in operation S 3700 . The source files decoded by the first user device  1000  are displayed on the first display  190  of the first user device  1000  based on the display information of the source files in parallel with a displaying operation of the second user device  2000  in operation S 3800 . 
       FIG. 11  is a flowchart for explaining an exemplary bidirectional display mirroring method carried out by the second user device  2000  according to an embodiment of the inventive concept. 
     Referring to  FIG. 11 , the second user device  2000  determines whether there is a display mirroring request from a user in operation S 4000 . In operation S 4000 , if it is determined that there is a display mirroring request from a user, it is determined whether the display mirroring request is for a first type display mirroring operation or a second type display mirroring operation in operation S 4100 . In a first type display mirroring operation, the first user device  1000  operates as a transmitting user device, and the second user device  2000  operates as a receiving user device. 
     When it is determined that the display mirroring request is for a first type display mirroring operation in operation S 4100 , the second user device  2000  receives compressed source files (e.g., audio/video/graphic files) and display information of the source files from the first user device  1000  by a wireless communication in operation S 4200 . The compressed source files and the corresponding display information may be transmitted from the first user device  1000  to the second user device  2000  before or while the first user device  1000  decodes the source files for displaying the source files. Next, the second user device  2000  decodes the received source files in operation S 4300 . The source files decoded by the second user device  2000  are displayed on the second display  290  of the second user device  2000  based on the corresponding display information in parallel with a displaying operation of the first user device  1000  in operation S 4400 . Then, the method proceeds to operation S 5500 . 
     On the other hand, in operation S 4100 , if it is determined that the display mirroring request is for a second type display mirroring operation, the second user device  2000  may decode compressed source files to be displayed in operation S 4500 , and in parallel with this, the second user device  2000  may transmit the compressed source files and corresponding display information to the first user device  1000  by a wireless communication in operation S 4600 . In a second type display mirroring operation, the second user device  2000  operates as a transmitting user device, and the first user device  1000  operates as a receiving user device. 
     In an exemplary embodiment, decoding in operation S 4500  and wireless transmitting in operation S 4600  of the second user device  2000  may be simultaneously performed. In another example, decoding in operation S 4500  may be performed after wireless transmitting in operation S 4600 . In the current embodiment of the inventive concept, wireless transmitting of the source files may be performed by UWB based WUSB. In this case, since it takes very short time to transmit the source files from the second user device  2000  to the first user device  1000  by wireless, decoding operations of the first and second user devices  1000  and  2000  may be performed substantially at the same time. 
     The source files decoded by the second user device  2000  in operation S 4500  may be displayed on the second display  290  of the second user device  2000  based on the corresponding display information in parallel with a displaying operation of the first user device  1000  in operation S 4700 . 
     When is determined whether there is a new command from a user during the display mirroring in operation S 5500 . If it is determined that there is a new command from a user in operation S 5500 , it may be determined whether the second user device  2000  has a picture in picture (PIP) function in operation S 5600 . The PIP function is technology of displaying a plurality of screens on a single display. In an exemplary embodiment, the second user device  2000  may be an A/V device including a large display and capable of displaying a plurality of screens on the display by technology such as PIP and picture by picture (PBP). 
     When it is determined that the second user device  2000  has a PIP function in operation S 5600 , the second user device  2000  may execute an operation corresponding to the users&#39; new command while executing the display mirroring in operation S 5700 . As a result, a display mirroring screen and at least one screen corresponding to the user&#39;s new command may be simultaneously displayed on the second display  290 . In this way, while performing a display mirroring operation, the second user device  2000  can executes another function or functions in response to a user&#39;s command. 
     On the other hand, in operation S 5600 , it is determined that the second user device  2000  does not has a PIP function, the second user device  2000  may interrupt its display mirroring operation selectively and perform an operation corresponding to the user&#39;s new command in operation S 5800 . For example, if a first type display mirroring operation in which the second user device  2000  operates as a receiving user device is currently performed, the second user device  2000  may interrupt its current display mirroring operation to operate in response to the user&#39;s new command. If a second type display mirroring operation in which the second user device  2000  operates as a transmitting user device is currently performed, the second user device  2000  may operate according to the user&#39;s new command without interrupting its current display mirroring operation. In this case, a result of the new operation of the second user device  2000  may be provided to the first user device  1000  by a display mirroring operation. 
     As described above, in the display mirroring method of the inventive concept, compressed source files and corresponding display information are directly transmitted from a transmitting user device to a receiving user device before the transmitting user device decodes the source files for displaying the source files. Therefore, during a display mirroring operation, it is unnecessary to compress source files again before transmitting the source files, and thus, decoding of re-compressed source files is unnecessary. As a result, bidirectional display mirroring is possible between different user devices without a time delay. 
     In addition, since user devices can decode source files individually according to their operational characteristics or display resolutions, display mirroring can be carried out without image deterioration caused by influence of the resolution of the other user device. Furthermore, if a user device has a multi-display function such as a PIP function, the user device can perform at least one additional function in response to a user&#39;s request without affecting its current display mirroring operation. 
     With reference to  FIG. 11 , an explanation has been given on the case where a new command is input from a user while a second type display mirroring operation is performed. This case is merely an example of the inventive concept. For example, operation S 5500  to operation S 5800  shown in  FIG. 11  may also be performed during a first type display mirroring operation. 
     The above-described display mirroring method may be an exemplary display mirroring method of the inventive concept. For example, the display mirroring method of the inventive concept can be applied to other operations such as a data streaming operation and a downloading operation among different kinds of user devices as well as the same kinds of user devices. 
       FIGS. 12A  and  FIG. 12B  are flowcharts for explaining an exemplary data streaming/downloading method carried out by the first user device  1000  according to embodiments of the inventive concept.  FIGS. 12A and 12B  illustrates an exemplary case where a wireless data streaming/downloading operation and a display mirroring operation are combined by a wireless data sharing method executable by the first user device  1000 . 
     Referring to  FIG. 12A , the first user device  1000  may determine whether a user requests a data streaming/downloading operation for transmitting multimedia contents from the second user device  2000  to the first user device  1000  in operation S 6000 . For example, various source files may be stored in the second user device  2000  which is configured as an A/V device having a large display. Source files of the multimedia contents may be stored in the main storage of the second user device  2000  after being compressed. In response to a user&#39;s request, various source files stored in the second user device  2000  may be selectively streamed/downloaded to the first user device  1000 . 
     Streaming is a method of transmitting and reproducing audio, video, or multimedia data. In the streaming method, data are transmitted like a continuous stream of wafer. According to the streaming method, although audio, video, or multimedia data are not completely downloaded, they can be displayed while receiving data packets in real time. 
     In operation S 6000 , if it is determined that there is a streaming/downloading request from a user, the source files of multimedia contents and corresponding display information are streamed/downloaded from the second user device  2000  to the first user device  1000  in operation S 6100 . In operation S 6100 , wireless transmission of the source files may be performed according to UWB based WUSB for guaranteeing a high transmission rate. However, this is an example of the inventive concept. That is, the inventive concept is not limited thereto. Various wireless networks may be used. 
     The source files stored in the second user device  2000  in a compressed state may be directly transmitted to the first user device  1000  without an additional transcoding operation. In this case, a receiving user device (that is, the first user device  1000 ) is not necessary to decode transcoded data, and thus high-rate wireless data sharing is possible among user devices without a time delay. 
     The source files of multimedia contents and the corresponding display information streamed/downloaded from the second user device  2000  in operation S 6100  are stored in the main storage or buffer of the first user device  1000  in operation S 6200 . The source files stored in operation S 6200  may be reproduced in real time or later according to a user&#39;s request. In the case where the source files stored in the first user device  1000  are reproduced later according to a user&#39;s request, the first user device  1000  is used as storage. In this case, as well as multimedia contents, other kinds of source files such as text files and data files may be stored in the first user device  1000 . 
     Referring to  FIG. 12B , before reproducing the source files stored in the first user device  1000 , the first user device  1000  may determine whether a user requests reproduction of the source file(s) stored in the first user device  1000  in operation S 7000 . If it is determined in operation S 7000  that a user requests reproduction of the source files streamed/downloaded to the first user device  1000 , it may be determined whether display mirroring is requested for the source files to be reproduced in operation S 7100 . 
     When it is determined that display mirroring is not requested for the source files to be displayed on the first user device  1000  (that is, for the source files streamed/downloaded from the second user device  2000  to the first user device  1000 ) in operation S 7100 , the source files are decoded in operation S 7200 , and the decoding result is displayed on the first user device  1000  with reference to the display information corresponding to the decoded source files in operation S 7300 . 
     When it is determined that display mirroring is requested for the source files to be displayed on the first user device  1000  in operation S 7100 , it is determined whether the display mirroring operation is performed in association with the second user device  2000  in operation S 7400 . 
     When it is determined that the display mirroring operation is performed in association with the second user device  2000  in operation S 7400 , the source files to be displayed on the first user device  1000  are decoded by the first user device  1000  in operation S 7500 . In this case, since the source files to be displayed on the first user device  1000  are already stored in the second user device  2000 , transmission of the source files from the first user device  1000  to the second user device  2000  is not necessary. Although not shown in  FIG. 12B , while the source files to be displayed on the first user device  1000  are decoded, the second user device  2000  may decode the source files stored in the second user device  2000 . These operations of the second user device  2000  may be controlled by a predetermined request signal transmitted from the first user device  1000  to the second user device  2000  in response to a user&#39;s request. Various kinds of requests signals may be transmitted between the first and second user devices  1000  and  2000  to perform a display mirroring operation. 
     The source files decoded by the first user device  1000  in operation S 7500  may be displayed on the first display  190  based on the corresponding display information. While the decoded source files are displayed on the first display  190 , a decoding result of the same source files may be displayed on the second user device  2000  in operation S 7600 . 
     If it is determined that the display mirroring operation is not performed in association with the second user device  2000  in operation S 7400 , the source files to be displayed on the first user device  1000  (that is, the source files streamed/downloaded from the second user device  2000  to the first user device  1000 ) may be decoded by the first user device  1000  in operation S 7700 , and in parallel with this, the source files and the display information corresponding to the source files may be transmitted to a third user device by wireless in operation S 7800 . In this case, the first user device  1000  operates as a transmitting user device, and the third user device operates as a receiving user device. The third user device may be any user device except for the second user device  2000  which is the first provider of the source files. For example, the third user device may be the same kind of device as the first user device  1000  or different in kind from the first user device  1000  and the second user device  2000 . In another example, the third user device may be the same kind of device as the second user device  2000  but a device not having the source files. The third user device is not limited to a particular device but can be selected from various devices. 
     In an exemplary embodiment, the decoding operation S 7700  of the first user device  1000  and the wireless transmission operation S 7800  may be simultaneously performed. In another embodiment, the decoding operation S 7700  may be performed after the wireless transmission operation S 7800  is performed. Although not shown in  FIG. 12B , while the source files to be displayed on the first user device  1000  are decoded, the third user device may decode the source files transmitted from the first user device  1000 . 
     In the current embodiment of the inventive concept, wireless transmission of the source files may be carried out by UWB based WUSB for a high transmission rate of several hundreds of Mbps. In this case, since it takes very short time to transmit the source files from the first user device  1000  to the third user device by wireless, decoding operations of the first user devices  1000  and the third user device may be performed substantially at the same time. The source files decoded by the first user device  1000  are displayed on the first display  190  of the first user device  1000  based on the corresponding display information in parallel with a displaying operation of the third user device in operation S 7900 . 
     Next, an explanation will be given on a data streaming/downloading method for the second user device  2000  that provides source files. 
       FIG. 13  is a flowchart for explaining an exemplary data streaming/downloading method carried out by the second user device  2000  according to an embodiment of the inventive concept. 
       FIG. 13  is a flowchart for explaining an exemplary data streaming/mirroring method carried out by the second user device  2000  according to an embodiment of the inventive concept.  FIG. 13  illustrates an exemplary case where a wireless data streaming/downloading operation and a display mirroring operation are combined by a wireless data sharing method executable by the second user device  2000 . 
     Referring to  FIG. 13 , the second user device  2000  may determine whether a user requests a data streaming/downloading operation for transmitting multimedia contents from the second user device  2000  to the first user device  1000  in operation S 8000 . 
     When it is determined that there is a streaming/downloading request from a user in operation S 8000 , the second user device  2000  transmits compressed source files of the multimedia contents stored in its main storage to the first user device  1000  by wireless without an additional transcoding operation in operation S 8100 . When the source files are transmitted in operation S 8100 , display information corresponding to the source files may be transmitted together with the source files. 
     In operation S 8100 , wireless transmission of the source files may be performed according to UWB based WUSB for a high transmission rate. According to the data transmission features of the current embodiment of the inventive concept, compressed source files stored in a transmitting user device (the second user device  2000 ) are directly transmitted to a receiving user device (the first user device  1000 ), and thus additional transcoding and resultant decoding are not necessary. Therefore, wireless data sharing between the first and second user devices  1000  and  2000  are possible without a time delay. 
     The wireless data sharing operation of the current embodiment can be performed together with the above-described display mirroring operation. 
     For this, the second user device  2000  may determine whether a user requests display mirroring in operation S 8200 . In operation S 8200 , if it is determined that a user requests display mirroring, the method may proceed to operation S 4100  of  FIG. 11  (refer to “B” in  FIGS. 13  and  FIG. 11 ) to perform a display mirroring operation. At this time, the second user device  2000  performs the same display mirroring operation as that shown in  FIG. 11 . Thus, a description thereof will not be repeated. 
     With reference to  FIGS. 12 and 13 , an explanation has been given on the case where a first or second type display mirroring operation is performed when stored data are displayed by a streaming/downloading operation. However, this is a mere example of the inventive concept. For example, according to the inventive concept, a streaming/downloading operation may be performed in parallel with a first or second type display mirroring operation. 
     The present general inventive concept can also be embodied as computer-readable codes on a computer-readable medium. The computer-readable medium can include a computer-readable recording medium and a computer-readable transmission medium. The computer-readable recording medium is any data storage device that can store data as a program which can be thereafter read by a computer system. Examples of the computer-readable recording medium include read-only memory (ROM), random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, and optical data storage devices. The computer-readable recording medium can also be distributed over network coupled computer systems so that the computer-readable code is stored and executed in a distributed fashion. The computer-readable transmission medium can transmit carrier waves or signals (e.g., wired or wireless data transmission through the Internet). Also, functional programs, codes, and code segments to accomplish the present general inventive concept can be easily construed by programmers skilled in the art to which the present general inventive concept pertains. 
     As described above, according to the wireless sharing system of the inventive concept, compressed source files stored in a transmitting user device can be directly transmitted from a receiving user device during a wireless data sharing or display mirroring operation. As a result, in a wireless data sharing or display mirroring operation, a transmitting user device is not necessary to decode compressed source files and transcode decoded display data, and a receiving user device is not necessary to decode received transcoded data. Therefore, display mirroring and wireless sharing of source files can be effectively performed without a time delay under limiting conditions such as the data transmission rate and bandwidth of a wireless network and power consumption limitation. 
     In addition, during a wireless data sharing or display mirroring operation, transmitting user device and receiving user device can decode source files individually without influence of the resolution of the other device. Therefore, display mirroring and wireless data sharing of multimedia contents can be performed without image deterioration. The display mirroring and wireless data sharing operations of the inventive concept can be bidirectionally performed among different kinds of user devices. The inventive concept is not limited to a particular user device but can be applied to various user devices, and the wireless sharing method and display mirroring method of the inventive concept can be applied to various user devices. 
     According to the inventive concept, display mirroring and wireless sharing of source files can be effectively performed in a portable electric device without time delay and image deterioration under limiting conditions such as data transmission rate and bandwidth of a wireless network and power consumption limitation. 
     In addition, according to the inventive concept, bidirectional display mirroring and multimedia contents sharing are possible among a portable electric device and the same or different kinds of devices. 
     Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the claims and their equivalents.