KR20100135155A - Method of messages exchanging and sink devices and source device - Google Patents

Abstract

PURPOSE: A message exchanging method, sync device and a source device are provided to transmit accurate information to the device of the other party by adding a reason code to a response message. CONSTITUTION: A sync device receives current A/V data from an active source device(S501), and transmits an action request message including a set active stream source message to a passive source device(S502). The passive source device transmits a response message to the active source device(S503), and the active source message device transmits the response message(S504).

Description

Method of messages exchanging and sink devices and source device}

The present invention relates to a message exchange method, a sink device and a source device, and more particularly, to a method and a sink device for exchanging messages between devices in a wireless network.

Recently, due to the development of communication, computer and network technology, many kinds of networks have been developed and implemented in real life. Networks exist in large networks that connect the world, such as wired or wireless Internet, while small wired or wireless networks exist that connect home appliances in confined spaces such as homes or workplaces. As the types of networks are diversified, interfacing technologies are also diversified to enable communication between networks and networks or by connecting devices and devices.

FIG. 1 is a diagram schematically illustrating an example of a wireless video access network (WVAN), which is a type of a wireless private access network (WPAN).

WVAN is a wireless network that can support uncompressed transmission of 1080P A / V streams by forming a wireless network between digital devices in a limited space within 10m, such as a home, and having a throughput of 4.5 Gbps or more with a bandwidth of about 7 GHz. to be. Therefore, it is a network configured between personal devices in a limited space, and the devices can be directly communicated between devices to configure a network so that information can be exchanged seamlessly between applications.

Referring to FIG. 1, the WPAN consists of two or more user devices 11-15, one of which acts as a coordinator 11. The coordinator 11 serves to provide basic timing of the WPAN, control quality of service (QoS) requirements, and the like. Devices that can be used as devices include computers, PDAs, notebooks, digital TVs, camcorders, digital cameras, printers, microphones, speakers, headsets, bar code readers, displays, mobile phones, etc., and all digital devices can be used.

The high-capacity video bus uses high-speed digital signal transmission of more than 1 Gbps to deliver 1080p or higher HD picture and high-quality audio data. However, these high-capacity video buses are transmitted through specific cables connected between devices, and there is an increasing demand for wireless real-time data transmission of high-speed A / V buses. The advantage is that the cable can be shortened and the distance between devices is not limited. However, in case of WLAN (IEEE802.11), A / V data and other data are regarded as the same general data in physical layer system and processed. There is difficulty.

Wireless video access network (WVAN), a type of wireless private access network (WPAN), treats A / V data and other data as the same general data in a physical layer system, so that it can be processed at high speed. There is a difficulty in achieving the purpose of transferring data on the bus.

Accordingly, A / V data transmission is attempted using WHDI (Wireless Home Digital Interface) wireless network. When sending <Action Reject> or <Wait> message in response to an AVCL message request, detailed information about the cause It did not tell me or did not tell me the cause.

The present invention has been made to solve the above problems, and proposes a message exchange method including information informing the status of a device that is the cause of transmission of a response message to an AVCL message request.

Technical problems to be achieved in the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

In order to achieve the above technical problem, a message exchange method for switching a source device in a sink device of a wireless network according to an embodiment of the present invention, the audio / video (A / V) receiving data, sending a first command to the second source device to confirm whether a second source device in the wireless network can transmit A / V data, the second source Receiving a second command from the first source device sent by the device in response to the first command, the second command including indication information indicating whether the second source device can transmit A / V data; Determining whether to switch to the second source device according to the indication information included in the second command. .

The indication information included in the second command may indicate that the second source device does not want or cannot transmit A / V data to the sink device. The A / V data received from the first source device may be included in a first downlink PHY data unit (DLPDU). The first command may be included in an uplink control PHY data unit (ULCPDU) and transmitted to the second source device. The second command may be included in a second DLPDU and received from the first source device.

Here, the first downlink physical layer data unit is transmitted during a time interval including a first time interval in which the MAC message and the at least one header are transmitted and a second time interval in which the A / V data is transmitted. Can be. In this case, the uplink control physical layer data unit may be transmitted during the first time interval.

The second command may be multiplexed with A / V data transmitted from the first source device to be included in the second DLPDU. The second DLPDU may include a basic header and an extended header, and the second command may be included in the extended header.

The transmitting of the first command to the second source device may include: a first identifier for identifying the transmitting device from an audio video control (AVC) layer in a medium access control (AVC) layer, and identifying the receiving device. Receiving the first command comprising a second identifier and an operation code (Opcode) for, by configuring a MAC message including a message preamble, a message type and the first command in the MAC layer physical layer ( Transmitting the uplink control physical layer data unit including an uplink control header, the MAC message, and audio / video (A / V) data in the physical layer; It may include transmitting to.

The MAC message may be multiplexed with the A / V data in the physical layer. The MAC message may include a cyclic redundancy check (CRC) code added at the MAC layer to detect an error in the receiving device.

In order to achieve the above technical problem, a sink device for receiving A / V data from a first source device in a wireless network according to an embodiment of the second aspect of the present invention, a first identifier for identifying the sink device And a first identifier received from the AVC layer, a message preamble, a message type, and an AVC layer that generates a first command including a second identifier for identifying a second source device and an operation code. A first physical layer data unit including a medium access control (MAC) layer for generating a MAC message including a command, an uplink control header, and the MAC message and audio / video (A / V) data; Generated and transmitted to the second source device, and transmitted by the second source device in response to the first command; A physical layer receiving a second physical layer data unit from the first source device, the second physical layer data unit including a second command including indication information indicating whether or not the A / V data can be transmitted, The sink device may determine whether to switch to the second source device according to the indication information included in the second command.

When the indication information included in the second command indicates that the second source device does not want or cannot transmit A / V data to the sink device, the A / V data may be received from the first source device. Can be.

Preferably, the first physical layer data unit may be an uplink control physical layer data unit (ULCPDU), and the second physical layer data unit is a downlink physical layer data unit (DLPDU) PHY Data UNIT).

The DLPDU may be transmitted during a time interval including a MAC message, a first time interval in which at least one or more headers are transmitted, and a second time interval in which A / V data is transmitted, and the ULCPDU should be transmitted with a portion of the DLPDU. May be transmitted during the first time interval.

The second command may be included in the DLPDU by being multiplexed with A / V data transmitted from the first source device, and the at least one header includes a basic header and an extended header. The second command may be included in the extension header.

In order to achieve the above technical problem, a sink device of a wireless network according to another embodiment of the present invention includes a receiver for receiving a broadcast signal from a first source device and a decoder for decoding the broadcast signal received by the receiver. A decoding unit, a display unit displaying content according to the broadcast signal decoded by the decoding unit, a broadcast signal received by the receiver unit, and a first command for confirming whether the second source device can transmit A / V data A second physical layer including a second command generated by the second source device in response to the first command by generating a first physical layer data unit including a MAC message; A network control module for receiving and processing a data unit from the first source device And determining whether to switch to a second source device through the second command processed by the network control module, to store the broadcast signal received by the receiver in a local storage device, or to play content stored in the local storage device. It includes a control unit for controlling.

The second command may include indication information indicating whether the second source device can transmit A / V data.

In order to achieve the above technical problem, a message exchange method for switching a source device of a sink device from a first source device in a wireless network according to an embodiment of the third aspect of the present invention, the second source device in the AVC layer In response to the first command sent from the sink device receiving audio / video (A / V) data from the sink device, the first source device including indication information indicating whether or not the A / V data can be transmitted. Generating a second command, constructing and transmitting a MAC message including a message preamble, a message type, and the second command received from the AVC layer to a physical layer in the MAC layer, at least one header in the physical layer , Physical layer data type including the MAC message and audio / video (A / V) data To be in phase and the sink device to be transmitted to the sink device via the second source device comprising: in response to the instruction information included in the second command to determine a switching whether to the first source device.

In order to achieve the above technical problem, the source device for receiving the first command from the sink device in the wireless network according to an embodiment of the fourth aspect of the present invention, the A / V data from the predetermined source device In response to the first command transmitted from the sink device, an AVC layer, message preamble, message type and the AVC layer for generating a second command including indication information indicating whether or not the source device can transmit A / V data; Generate a physical layer data unit including a MAC layer configured to deliver a MAC message including a second command to the physical layer and at least one header, the MAC message, and audio / video (A / V) data; A physical layer for transmitting to the sink device through a source device; In the device according to the instruction information included in the second command it may be to determine whether or not the switching to the first command is the first transmission source device.

In the message exchange requesting a connection for A / V streaming between user devices, the present invention can deliver more accurate information to the counterpart device by adding a code indicating the cause when the device indicates the device state through the response message. Specifically, when transmitting an action reject response message, the code identifying the cause of the reject is differentiated in more detail than before, so that information exchange between devices is accurate and errors can be reduced.

In addition, when the waiting message is transmitted, the message exchange may be performed by including <WaitTime> and <WaitReason>, and thus more accurate signal transmission may be performed through information on the estimated delay time and the cause of the delay.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. There will be.

In order to solve the above technical problem, embodiments of the present invention disclose a wireless path performance test method for A / V data transmission in a wireless home digital interface (WHDI) wireless network.

The following embodiments are a combination of elements and features of the present invention in a predetermined form. Each component or feature may be considered to be optional unless otherwise stated. Each component or feature may be implemented in a form that is not combined with other components or features. In addition, some of the elements and / or features may be combined to form an embodiment of the present invention. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments.

Recently, Wireless Home Digital Interface (WHDI) wireless system is a technology that transmits uncompressed A / V data to 5Ghz U-NII band. WHDI converts high-capacity video bus data into radio more efficiently by processing and modulating A / V data in consideration of human audio-visual characteristics in the PHY layer. At this time, in order to evaluate the wireless performance, a technique such as radar detection of 5Ghz band of wireless signal strength is applied to the receiver. WHDI needs a technique that can properly evaluate the transmission performance of control data or non-A / V data. This is because it is possible to easily implement functions such as setting a wireless path, setting a retransmission window, and evaluating the response performance of the host system.

At least one user device included in the WHDI includes a source device transmitting A / V data and a sink device receiving A / V data from the source device. Here, a source device that actually transmits A / V data may be considered an active source device, and a sink device that receives an audio / video signal does not actually transmit A / V data and is added to the active source device. It includes passively connected passive source devices. Each device may be divided into at least three layers according to its function, and generally includes a PHY layer, a MAC layer, and an AVC layer.

2 is a diagram illustrating an embodiment of a broadcast signal processing system including a broadcast signal receiver as an example of a transmission device in a WHDI network.

The broadcast signal receiver may reproduce A / V data received through an A / V data input through an antenna from a broadcasting station or cable satellite, etc., as described below. In addition, when the broadcast signal receiver operates as a transmitting device on the WHDI network, the broadcast signal receiver may remotely transmit the received A / V data to at least one or more receiving devices.

Referring to FIG. 2, a broadcast signal processing system as an example of a transmission device includes a broadcast signal receiver 21 and a network device 24 connecting a broadcast signal receiver and a remote storage device or another device 25.

The broadcast signal receiver 21 includes a receiver 211, a demodulator 212, a decoder 213, a display 214, a controller 215, a network control module 216, a graphic processor 217, an interface unit. 218 and a control signal communication unit 219. Here, the example of FIG. 2 further includes a local storage device 23, which discloses an example in which the local storage device 23 is directly connected to an interface unit 218 including an input / output port, but the local storage device is a broadcast signal. It may be a storage device mounted inside the receiver 21.

The interface unit 218 may communicate with the wired / wireless network device 24 and may be connected with at least one receiving device 25 present on the wireless network through the network device 24. The control signal communication unit 219 may receive a user control signal according to a user control device, for example, a remote controller 22, and output the received signal to the controller.

The receiver 211 may be a tuner that receives a broadcast signal of a specific frequency through at least one of the terrestrial wave, satellite, cable, and the Internet. The receiver 211 may be provided for each broadcast source, for example, terrestrial wave, cable, satellite, or personal broadcast, or may be an integrated tuner. In addition, assuming that the receiver 211 is a terrestrial broadcast tuner, the receiver 211 may include at least one digital tuner and an analog tuner, or may be a digital / analog tuner.

In addition, the receiver 211 may receive an IP (internet protocol) stream transmitted through wired or wireless communication. When receiving the IP stream, the reception unit 211 may process transmission and reception packets according to an IP protocol for setting source and destination information on the received IP packet and the packet transmitted by the receiver. The reception unit 211 may output a video / audio / data stream included in an IP packet received according to the IP protocol, and generate and output a transport stream to be transmitted to the network as an IP packet according to the IP protocol. . The receiver 211 is a component that receives an externally input video signal. For example, the receiver 211 may receive a video / audio signal input of an IEEE 1394 format or a stream such as HDMI from an external source.

The demodulator 212 demodulates the input broadcast signal in the inverse of the modulation scheme. The demodulator 212 demodulates a broadcast signal and outputs a broadcast stream. When the receiver 211 receives a stream type signal, for example, when receiving the IP stream, the IP stream bypasses the demodulator 212 and is output to the decoder 213.

The decoder 213 includes an audio decoder and a video decoder, and after decoding the broadcast stream output from the demodulator 212 or the stream reproduced through the network control module 216 with each decoding algorithm, the display unit 214. ) At this time, between the demodulator 212 and the decoder 213 may further include a demultiplexer (not shown) for separating each stream according to the corresponding identifier. The demultiplexer may divide a broadcast signal into an audio element stream (ES) and a video element stream (ES), and output the broadcast signal to each decoder of the decoding unit 213. In addition, when a plurality of programs are multiplexed on one channel, only a broadcast signal of a program selected by a user may be selected and divided into a video element stream and an audio element stream. If the demodulated broadcast signal includes a data stream or a system information stream, it is also separated from the demultiplexer and delivered to the corresponding decoding block (not shown).

The graphic processor 217 may control a graphic to be displayed to be displayed on the display unit 214 so that the display unit 214 may display a menu screen or the like on the video image displayed.

The interface unit 218 may interface with at least one receiving device 25 through a wired or wireless network. Examples of the interface unit 218 may include an Ethernet module, a Bluetooth module, a short-range wireless Internet module, a portable Internet module, a home PNA module, an IEEE1394 module, a PLC module, a home RF module, and an IrDA module. Meanwhile, the interface unit 218 may output a control signal for turning on power to the remote storage device. For example, although not illustrated in FIG. 2, the interface unit 218 may turn on the power of the remote storage device by transmitting a WOL signal to a network interface unit where a separate remote storage device communicates.

When the broadcast signal receiver 21 shown in FIG. 2 transmits a broadcast signal received by the network signal receiver 21 to another device on a WHDI network, the network control module 216 may convert the broadcast signal received from the receiver 211 into a MAC message. A module that works together to transmit data through physical layer data units. The network control module 216 may receive a broadcast signal directly from the receiver 211 or a demodulated broadcast signal from the demodulator 212. In the former case, the encoding process may be omitted. In addition, the broadcast signal received by the receiver 211 may be input to the protoco layer module 216 through a process for signal transmission from the controller 215. For example, when receiving a message including a broadcast signal from the reception device 25, the received message is divided into a broadcast signal and a MAC message by the network control module 216, and the separated broadcast signal (or broadcast stream). May be input to the decoding unit 213, decoded by a decoding algorithm, and then output to the display unit 214.

The network control module 216 may include an AVC layer for generating a predetermined AVCL command, a MAC layer for generating a MAC message including an AVCL command received from the AVC layer, and the receiving unit 211 or the demodulator 212. The control unit 215 may control the PHY layer generating the first physical layer data unit including the broadcast signal and the MAC message received from the second control unit. The first physical layer data unit may be transmitted to another device using the network device 24 via the interface 218. In addition, the network control module 216 may receive a second physical layer data unit including a response message transmitted by the receiving device having received the AVCL command in response thereto.

In FIG. 2, an example in which the controller 215 and the network control module 216 are separately provided for convenience of description is described, but may be implemented as one system chip as shown by a dotted line. In detail, in the protocol layer including the AVC layer, the MAC layer, and the PHY layer to be controlled by the network control module 216, the AVC layer and the MAC layer are connected to the message or the received message to be transmitted in the controller 215. Can be made. At this time, the PHY layer forms a block layer data block in the network control module 216. A detailed description of the network control module 216 will be described later with reference to the physical layer data block structure disclosed in FIGS. 9 to 16.

The controller 215 may control operations of the illustrated components (receiver, demodulator, decoder, display, graphics processor, network control module, interface), and the like. Then, the menu for receiving the user's control command can be displayed, and the user can be driven with an application for displaying various information or menus of the broadcast signal processing system.

For example, the controller 215 may read content stored in the local storage device 23 when the local storage device 23 is mounted. When the local storage device 23 is mounted, the controller 215 may control to store the broadcast content received from the receiver 211 in the local storage device 23. In addition, the controller 215 may output a signal for controlling the local storage device 23 to mount according to whether the local storage device 23 is mounted.

In addition, the controller 215 checks the remaining storage capacity of the local storage device 23 and allows the user to display the information on the display unit 214 through the display unit 214 or the graphic processor 217. Can be. When the local storage device 23 lacks the remaining storage capacity, the controller 215 may transfer the content stored in the local storage device 23 to the remote storage device. In this case, when the remaining storage capacity of the local storage device 23 is insufficient, the controller 215 transmits the information to the local storage device 23 to another local storage device (not shown) or a remote storage device through the display unit 214. A menu indicating whether to move and store the stored content can be displayed. And it can receive and process the user's control signal for it. Accordingly, the controller 215 may move and store contents stored in the local storage device 23 and other directly or remotely mounted storage devices.

The display unit 214 may display broadcast content received from the receiver 211 and content stored in the local storage device 23. According to a control command of the controller 215, a menu for displaying information related to whether the storage device is mounted and the remaining capacity may be displayed and operated under the control of the user.

According to one embodiment of the invention, the transmission device structure shown in FIG. 2 is an example of a sink device that receives A / V data from an active source device, and determines switching to another source device (eg, a passive source device). The network control module 216 may generate a command for confirming whether the passive source device can transmit A / V data. In the message exchange for switching of the source device, the receiving device 25 in FIG. 2 will be an example of a passive source device.

3 is a diagram illustrating an example of a protocol hierarchy implemented in a device in a WHDI system, which is performed by the network control module 216 of FIG. 2.

Referring to FIG. 3, the WHDI system may be configured in all four layers.

The uppermost Application Layer 31 is a layer for the user to integrate WHDI in their host system.

The AVCL layer 32 is an upper layer that is responsible for streaming connection and device control for A / V data transmission between a source device and a sink device. AVCL is used to indicate the active source device that the sink device wishes to receive the A / V stream from the particular source device. The sink device may not need to receive and render the A / V stream or further receive the A / V stream. On the other hand, the source device is used to indicate a specific display that the user has requested to display the content on the display unit of the source device. Or, it is used to determine a capacity related to the A / V data of the sink device at the source device, or to transmit metadata related to the A / V data. Alternatively, all devices are used to perform Remote Device Control (RDC), such as controlling the playback or channel variation of a disc player on a set top box.

As such, AVCL includes two types of control schemes: control protocols and metadata delivery. Here, the control protocol (or AVCL protocol) includes bidirectional command transmission between devices on the active network. In general, a message including an AVCL command is mapped to a MAC message through the MAC layer and mixed with other data in the PHY layer, which will be described later.

Next, the media access control (MAC) layer 33 is a lower layer of the data transmission protocol and performs functions such as link setup, connected or disconnected, channel access, and reliable data transmission. That is, it transmits a control / data message or controls a channel.

The MAC layer performs a carrier carrier multiple access with collision avoidance (CSMA / CA) using an ACK frame as a basic channel access scheme, and performs subcarrier detection or clear channel assessment (CCA) before sending a packet. . In addition, in consideration of the direction between the source device and the sink device, it is divided into downlink and uplink. The downlink may be implemented in one long frame as a whole, and the process of receiving and recovering the ACK frame may be omitted. In downlink, the transmission time is determined according to the format of the A / V data to be transmitted because synchronization between the transmitted video frame and the modem (PHY) frame is performed. In general, the entire MAC format includes a Basic Header (BH) and an Extended Header (EH).

Next, the PHY layer 34 can directly process A / V data and simultaneously be processed by the MAC layer 33. In WHDI, the PHY layer is responsible for transmitting and receiving unmodulated A / V data. The PHY layer serves to switch messages requested from higher layers such as the AVCL layer 32 and the MAC layer 33 to take care of the radio signal, thereby allowing the request message to be transmitted between devices by the physical layer. . In addition, the PHY layer has A / V data unidirectional transmission capacity and bidirectional data channel capacity, PHY level encryption and SNR for all A / V data, carrier detection and interference determination Measurement is also possible.

The PHY layer receives or outputs pre-processed video data samples or various forms of pre-processed audio data samples in the form of Y, Cb, Cr streams at 4: 4: 4 ratio of pixels at each source / sink device. All transitions in this form are performed at the application layer 31 on each source / sink device.

4 is a block diagram illustrating an example of a source device in a WHDI system.

Referring to FIG. 4, a host controller 41, which is a kind of processor, integrates and manages the entire system and serves as an AVCL layer, or uses a WHDI baseband module 43 as an inter integrated circuit (I2C). It controls the bus system structure. Because the I2C bus system operates on the I2C protocol, multiple ICs can connect and communicate with each other over a common structured bus. I2C bus systems provide a way to connect a central processing unit (CPU) and associated peripheral ICs (ie, provide communication between them) in a television environment, and are widely used in consumer electronics. I2C systems are generally limited to transmitting data at a set clock rate in accordance with a set protocol, and the main controller IC of the I2C system sets the transfer rate or speed (ie, clock rate or bus speed). Thus, all ICs connected to a particular I2C bus must communicate at the same rate or data rate. The host controller 41 may include a memory therein or use an external memory.

Next, the WHDI baseband module 43 plays the role of the MAC / PHY Layer described above, and receives the A / V data from the A / V source device (A / V source) 42 to the bus such as LVDS to receive the WHDI RF. Transmit to module 44 at intermediate frequency IF. The WHDI RF module 44 converts the intermediate frequency IF into a carrier signal and transmits the converted microwave signal through the multiple antennas 45. It is also possible to transmit as well as receive the control signals other than the A / V data.

5 is a diagram illustrating an example of a sink device in a WHDI system.

Referring to FIG. 5, the host controller 51, which is a kind of processor, plays an integrated role of an application like the above-described source device, and uses a WHDI baseband module 54 to construct an inter integrated circuit (I2C) bus system. Serves as a control. The WHDI RF module 53 converts the RF signal received from the multi-antenna 52 into an intermediate frequency (IF), restores A / V data received from the source device, and outputs LVDS, Transmit A / V bus signals such as I2S.

FIG. 6 is a diagram illustrating a process of converting a general video signal including a vertical blanking period into an RF signal in a WHDI device in which A / V data transmission and reception are performed.

In general, a period in which a source device continuously transmits a radio signal to a sink device is called a downlink period. In this period, a downlink PHY data unit (DLPDU) is transmitted. The downlink period can be largely divided into a vertical blanking period section 61 and an active video section 62. First, the vertical blanking period section 61 includes a section 611 in which the source device transmits a downlink preamble including a channel estimation sequence (CES) to the sink device, and a section 612 in which a downlink header is transmitted. ). CES is a technique for measuring distortion of a received signal, that is, time delay, phase shift and attenuation, which occurs when a transmitted signal passes through an unspecified wireless channel, by using a pilot signal having a constant pattern included in the transmitted signal. In the active video section 62, the source device transmits A / V data to the sink device.

The WHDI source device in A / V data transmission / reception operation may continuously transmit a 5 Ghz signal including control information and video data corresponding to a wireless signal during the downlink period. The time required for the downlink period corresponds to the sum of some of the general vertical blanking period sections of the video bus (component, HDMI, LVTTL, etc.) and one active video section in which actual video data is transmitted. That is, the signal transmission time is determined according to the data type transmitted from the source device, and the PHY signal may be transmitted in units of 10 ms or more longer than other RF communication in the downlink period.

The downlink period is followed by an uplink period. The uplink period is a period in which the PHY layer of the sink device can transmit a radio signal to the source device. The uplink period consists only of a portion 63 of a general vertical blanking period of a video bus (component, HDMI, LVTTL, etc.). An uplink control PHY data unit (ULCPDU), which is an uplink section, includes an RF turn around section 631, a section 632 for transmitting a preamble including a CES, and a section for transmitting an uplink header ( 633), and a section for transmitting uplink data 634 and a slience + RF Turn Around section 635.

An interval 632 for transmitting an uplink preamble including CES is a signal interval for synchronization of a device receiving an uplink radio signal. In addition, the RF Turn Around section 635 corresponds to the time required to switch the transmitting antenna to the receiving antenna or the receiving antenna to the transmitting antenna. That is, the Slience + RF Turn Around section 635 is a period of stopping for a while and corresponds to the time required for the sink device to switch from the transmission mode to the reception mode, and for the source device to switch from the reception mode to the transmission mode.

After the uplink period ends, the preamble / CES transmission section 611 and the downlink header transmission section 612 of the downlink section continue to fill one vertical blanking period section 61.

In this way, the WHDI PHY layer in A / V transmission operation can define the lower transmission interval according to the time configuration (that is, the interval between the vertical blanking period and the active video interval) of the original signal of the video data transmitted. have. In the downlink and the uplink, each transmission period is identical in that it uses OFDM and MIMO techniques, but the PHY signal generation and transmission methods are different from each other.

The source device configures its own voice, video, and control data as a DLPDU using a downlink section consisting of a vertical blanking period section 61 and an active video section 62 in the PHY layer, and transmits it as a wireless signal to the sink device. . The period is mainly divided into a video dependent DLPDU mode for transmitting only video data and a video independent DLPDU mode for transmitting data unrelated to the video data, which will be described below with reference to FIGS. 7 and 8.

7 is a diagram illustrating an example of a DLPDU sequence in a video independent DLPDU mode in a WHDI PHY layer.

Referring to FIG. 7, when a source device starts a network, the source device broadcasts its presence through a Video Independent DLPDU that is not related to A / V data to find a sink device. Video Independent DLPDUs are similar to beacon messages, but control information such as time information for synchronization or device lists in the network is carried in the DLPDU's base header (BH) and extension headers (EH). The difference is that they can be sent at the same time. Another purpose of the Video Independent DLPDU is to shorten the time required for transmitting audio signals only to sink devices. Video Independent DLPDUs require a relatively short time of less than 5ms because they do not need to be synchronized to the video bus signal.

Referring to FIG. 7, when the source device transmits an independent DLPDU without A / V data to find a sink device, the frequency F _DLI [0] indicates different center frequency ranges within the 5Ghz U-NII range. For example, within the 5Ghz U-NII range, F _DLI [0] is 5150Mhz, and F _DLI [1] is 5470Mhz. The source device broadcasts its information over all channels, thereby inducing the sink device in the waiting state to respond.

8 is a diagram illustrating an example of a DLPDU sequence in a video dependent DLPDU mode in a WHDI PHY layer.

Referring to FIG. 8, the purpose of the Video dependent DLPDU is for the source device to synchronize its frequency to the video signal prior to the radio signal. For example, if the source device is transmitting a 1080p 50hz video signal to the sink device using downlink, the DLPDU signal is generated for about 18 ms, which is a signal interval when the active video device, that is, the DE signal is on, from the active source device. Lasts. As shown in FIG. 8, when the first DLPDU is transmitted, the direction of the signal is changed and the first sink device transmits ULCPDU (Uplink Control PHY Data Unit) data using the uplink to the source device. Thereafter, when the ULCPDU signal transmitted from the first sink device is transmitted to the source device, the next DLPDU signal is transmitted, and then the ULCPDU signal is transmitted from the second sink device to the source device, and the same process is repeated. Header information of the ULCPDU and DLPDU is included in the vertical blanking period of the video signal and transmitted. That is, the sink device may transmit the PHY signal for a relatively short time within 500us.

Next, FIG. 9 is a diagram illustrating an example of a PHY structure for transmitting a DLPDU in a WHDI system.

In the DLPDU PHY structure of the WHDI active source device, the radio encoding process may be variously implemented according to the type of data to be transmitted. In particular, in the case of video data, each frame (eg, each image) is decomposed into one or more color components (Y, Cb, Cr), and the decomposed frame of color components is decomposed into frequency components and then quantized. Herein, the error of the quantization result is a video fine stream, and the quantized frequency components are separated into a video coarse bitstream. The video quantization error stream and the video quantization coefficient bitstream are the same. Different video encoding processes are applied to video data.

Referring to FIG. 9, the data transmitted in the WHDI DLPDU PHY structure includes data / control bitstreams, which are message command data requested from the MAC and AVCL layers, and signal accuracy at the receiver. The test bitstream, which is a constant bit pattern mixed with the data, can be classified into an audio bitstream for transmitting audio data and a video bitstream for transmitting video data. The video bitstream may be divided into a video quantization coefficient bitstream which transmits quantized video data and a video error bitstream which is a bitstream of an error value corresponding to each of the quantized data.

The video quantization coefficient bitstream is a bitstream consisting of coefficients quantized after de-correlation transform (DCT) of video data, and the video quantization error bitstream is a quantization error generated after DCT transforming video data. Bitstream.

As described above, the signal generation method differs according to the type of data transmitted from the PHY system. Referring to the example illustrated in FIG. 9, the audio data and the video data pass through the encoders 71 and 72, respectively. Control data such as a data / control bitstream and a test bitstream are transmitted to the bitstream MUX 73 without undergoing an encoding process. The video quantization coefficient bitstream of the video data is also transmitted to the bitstream MUX 73 after the encoding process so that a total of four signals are combined into one bitstream. In this case, the video dependent DLPDU mode includes the video quantization coefficient bitstream, but in the independent DLPDU mode, the quantization coefficient bitstream is excluded.

Next, the Coarse Stream Encryptor 74 combines all the data except the header information BH and EH in the AES-128 method for the signal input by being combined into one bitstream in the bitstream MUX 73. Encrypt The bitstream processer 75 modulates the encrypted signal into a wireless signal (Symbol) based on the QAM scheme and adds an error correction code.

On the other hand, video quantization error is processed independently by the quantization error data processing and encryption module (Fine Data Processing and Encryption module) 76 to transmit the data more securely, unlike the above four data. In this case, the quantization error data processing and encryption module 76 includes a quantization error data scaling module, a quantization error data symbol mapper, and a quantization error data. A fine-data encryptor and a quantization error data scrambler may be included.

In the above example, a total of five data processed through the separate processing described above is the video quantization error data passed through the quantization error data processing and encryption module 76 and the remaining four data combined into one data. Is input to the MIMO OFDM mapper 77. The MIMO OFDM mapper 77 distributes the input signal to the RF-chain module 78 transmitted through a subcarrier or each transmit antenna in order to apply MIMO based on antenna diversity, channel matrix calculation, and inverse transform. Here, dedicated subcarriers may be allocated to carrier signals having different center frequencies according to video quantization coefficients and video quantization errors.

In the Nth transmit chains 78, the downlink IDFT unit 781 performs a process of converting the finally calculated subcarrier signals to the time axis and integrating them. The CP inserter 782 performs a process of copying a block of a predetermined size from the back of the previous symbol to the front of the next symbol to avoid multi-path interference that may occur between OFDM symbols. The preamble Mux 783 rearranges signals so that only preamble data is transmitted in the preamble transmission sections 611 and 632 shown in FIG. 6. In the Symbol Shaper 784, a signal processing process is performed such that the signal strength in the frequency domain falls within the spectral mask required by the WHDI system. The final signal is converted from the analog and RF module (785) to an analog signal via a digital-to-analog converter, and the converted intermediate frequency (IF) is converted into a 5Ghz radio signal (RF) through a mixer. It is converted and transmitted through the antenna.

In the above, the process of transmitting the audio signal and the video signal through the antenna through the DLPDU PHY structure in the WHDI system has been described.

In short, WHDI's active source devices always perform DCT conversion on video data directly received at the PHY layer before transmitting radio signals. In addition, by quantizing the DCT-converted video data, in fact, the transmission data may be compressed to transmit more data within a limited bandwidth. The quantized video data is divided into video quantization coefficient data and video quantization error data, and different error correction encoding processes are applied. Alternatively, different modulation schemes may be applied to the separated video quantization coefficient data and the video quantization error data.

Hereinafter, each component in the subsystem of the DLPDU PHY layer of the WHDI active source device will be described in more detail.

10 is a diagram illustrating a structure of an audio encoder in an example of the DLPDU PHY structure of the WHDI active source device.

Referring to FIG. 10, the audio encoder 71 is composed of two elements, an audio outer encoder 711 and an audio byte interleaver 712. The Audio Outer Encoder 711 uses a Read-Solomon method as preprocessing for audio data. The polynomial used for this is P (x) = 1 + x ^ 2 + x ^ 3 + x ^ 4 + x ^ 8. For example, a total of 255 bytes is added by adding 16 bytes of the same value to 239 bytes of data. Generate the output. This result is again mixed by the convolutional byte-interlever in the audio byte interleaver 712, which can reduce distortion of the voice signal resulting from radio error.

FIG. 11 is a diagram illustrating a structure of a video encoder in an example of the DLPDU PHY structure of the WHDI active source device.

The video encoder 72 DCT-converts the uncompressed Y, Cb, Cr format video data (eg, pixels) into the frequency domain, and quantizes the converted signal into DC and AC components, respectively. An error generated in the quantization process is extracted as a video quantization error stream. The quantized value is extracted as a video quantization coefficient bitstream. After DCT conversion of the frequency, the high energy coefficient of the frequency component as low as the number proportional to the available transmission amount measured in the MAC layer is selected and transmitted to the unit where the next process is performed, and the remaining signals are discarded.

More specifically, referring to FIG. 11, all pixels are first grouped into 8 × 8 blocks in the block grouping unit 721 for DCT conversion of video data. For example, when performing block grouping on a pixel of 1920x1080 full HD size, it may be grouped into 240x135 blocks. Because grouping into 8x8 blocks, the horizontal blanking of the video bus should be buffered by storing at least eight times in the video memory of the transmitter.

The block interleaver 722 interleaves the columns and rows of each block as shown in FIG. 12 for 240x135 blocks or some blocks, for example, on a full screen of 1920x1080 full HD size to avoid cluster errors. (interleaving) to perform the mixing process. FIG. 12 is a diagram illustrating an example of block interleaving performed by the video encoder illustrated in FIG. 11.

Next, in the spatial de-correlation module 723 that performs DCT transformation, the block interleaver 722 converts each block whose column and row permutations are changed into frequency components through DCT transformation. That is, spatial de-correlation in each block is performed to generate a set of coefficients for each block. The performance of the signal converted to the frequency component varies depending on the value of the corresponding coefficient. Referring to FIG. 11, a block type detector for inputting a coefficient parsing and selection module 726 for analyzing and selecting coefficients according to coefficient values, or determining a type of each block; 724, and is input to a coefficient parsing and selection module 726 through a block processing mode controller 725 that controls a processing mode of each block.

The block type detector 724 finds the type of each video block. In this case, two types of block types may be defined as type 0 and type 1. In general, a block having a low energy in a high frequency coefficient after DCT conversion may be set to type 0, and a block having a high energy in a high frequency coefficient may be set as type 1. This particular block type determination criterion may be a specific performer capable of satisfying the required image quality.

Next, the block processing mode controller 725 performs a process by applying one of the first mode and the second mode to all blocks. The first mode is applied to all blocks in basic mode, while the second mode is applied to blocks that do not change through the number of consecutive video frames in refinement mode. The decision criterion for the mode of processing a particular block may be a particular performer capable of meeting video quality requirements. The first mode is to selectively discard high frequency components and apply a quantization process in the DCT converted video signal, thereby generating a relatively small amount of video data. On the other hand, in the second mode, a relatively large amount of image data can be transmitted by selectively discarding a high frequency component in the DCT-converted video signal and performing quantization and error signal extraction. However, in order to apply the second mode when the source device transmits the video data, the refinement mode must support the second mode in the sink device. Uncompressed transmission is also possible if the second mode process is applied to all blocks and there is no process of discarding high frequency components.

Next, in the coefficient parsing and selection module 726, the block type determined by the block type detector 724 and the block processing mode controller 725 are performed. Analyzes and selects coefficients for the video quantization error stream of each block based on block processing mode control indications, coefficient information tables for selecting appropriate coefficients, and available bandwidth provided by the MAC layer.

In the MAC layer, N _{Coeffs _ per _ Block} is set. N _{Coeffs _ per _ Block} is a coefficient value per _{block, which} is determined by combining the current wireless reception sensitivity and other performance values. For example, when the distance between the source device and the sink device is too great and the wireless channel situation is not good, by setting the N _{Coeffs_per_Block} value small, the high frequency component of the coefficient is automatically discarded.

Next, the coefficient quantizer 727 may include a block type detector 725, a block processing mode controller 725, and a coefficient parsing and selection module; Perform quantization on the signal transmitted from 726. To generate a video quantization coefficient bit stream and a video quantization error stream for complex symbol values, based on the type of each block, detailed control indication information, the appropriate quantization table, the available bandwidth provided by the MAC layer, and the like. Coefficients of each block can be quantized.

A subset of the DCT coefficients is quantized for each video block. Each quantized coefficient is represented in two types, such as a sequence of one or more quantized bits and a video fine coefficient. The non-quantized coefficients remain unchanged and are referred to as video quantization error coefficients below.

The quantization process performed by the coefficient quantizer 727 may be performed as follows.

_, 그것의 출력 비트의 개수에 따라 각각의 양자화가 특정된다.1) Nine kinds of standard quantization can be used for the DCT of the DC component of the signal. For example,

_, Each quantization is specified according to the number of its output bits.

_, 그것의 출력 비트의 개수에 따라 각각의 양자화가 특정된다. 2) Three kinds of nonstandard quantization can be used for DCT coefficients for non-DC components, i.e., AC components. For example,

_, Each quantization is specified according to the number of its output bits.

로 양자화되고, 상기 양자화는

에 따른 N-bit 양자기에 의해 양자화된다고 가정한다. 양자화 과정은 다음과 같다.Each N-bit coefficient quantization is defined as a ^2N quantization region including ^2N quantization values corresponding to one quantization region and ^2N N- bit sequences respectively corresponding to one quantization region. DCT coefficient

Quantized by

Assume that it is quantized by an N-bit quantizer according to. The quantization process is as follows.

가 주어진 양자화 영역

을 찾는다. 수학적으로, 이것은

에 따라 수행된다. (where if means if and only if)1) coefficient

Quantization region given

Find it. Mathematically, this is

Is performed according to. (where if means if and only if)

에 해당하는 양자화 값인

를 산출하기 위해 계수

를 양자화한다.2) quantization domain

The quantization value corresponding to

Coefficient to yield

Quantize

를 생성한다. 상기 N-bit 시퀀스는 스트림에서 가장 먼저 출력되는 b₀비트를 포함하는 양자화 과정에서의 비트 시퀀스 출력이다.3) N-bit sequence corresponding to quantization region

. The N-bit sequence is a bit sequence output in the quantization process including the b ₀ bits output first in the stream.

4) Compute the quantization error defined by. The quantization error is a video quantization error coefficient generated during the quantization process.

이 되고, 비트 시퀀스는 생성되지 않는다. For coefficients that are not quantized,

, The bit sequence is not generated.

Hereinafter, quantization bits calculated for each video block will be described with reference to FIG. 13. FIG. 13 is a diagram illustrating quantization bits calculated per video block in a DLPDU PHY structure of a WHDI active source device. FIG.

The selection of quantized coefficients and the number of bits may be allocated according to a first block mode or a second block mode, a video format and a bandwidth limit, and a second block mode that processes all quantization bits. The processed video block is set to zero.

_And, all number of blocks the entire quantized by the MAC layer is N _{Bits per _ _ Block -} is set to be. The MAC layer also makes the value of the parameter N _{Bits _ per _ Block -} less than 0 and less than 64. The value of the parameter N _{Bits _ per _ Block -} is used for rate adjustment by adding a single bit with a value of '0' to the first video block N _{Bits_fraction-} within all groups of 64 video blocks. . At this time, by obtaining a constant bit rate when the average is more than 64 video block groups, rate adjustment is started from the first video block. This bit is referred to as the rate adjustment bit. When adding rate adjustment bits, add all the output bits of the block after quantization. The bit generated for each video block should be determined in advance by a type bit indicating the type of video block. When the type bit is calculated, it must be performed prior to quantization and rate adjustment of any bit. The type bit should have a value of '0' for a type 0 block and a value of '1' for a type 1 block.

Prior to the type bits, quantization bits and rate adjustment bits, processing bits representing the processing of the video block must first be set. The processing bit is set to '0' in the source device of every block when transmitting a signal to a sink device that does not support the above-described second block mode.

After quantization is performed, it is extracted into a video quantization error stream, which is the difference between the quantized coefficients and the value before the quantization is performed.

Next, the bitstream MUX 73 converts four bitstreams (data / control bitstream, audio encoder output bitstream, video quantization coefficient bitstream and test bitstream) into one quantization coefficient bitstream. Mix to process. At this time, the header information (BH, EH) is excluded from the control information. The coarse stream encrytor 74 encrypts the video quantization coefficient bitstream except for the header information BH and EH processed as one stream in the bitstream MUX 73.

Next, the bitstream processer 75 will be described with reference to FIG. 14.

FIG. 14 is a diagram illustrating a bitstream processor in one example of a DLPDU PHY structure of a WHDI active source device. FIG.

The bitstream processer (75) uses the TAIL Bits Inserter (751), Convolution Encoder (752), Bit Interleaver (753), Symbol Mapper (754), Symbol Parser (755), and Space Time Block Code (STBC) Encoder (756). It may include.

The video quantization coefficient bitstream enhances the error correction code rather than the video quantization error stream to be transmitted. Referring to FIG. 14, an error correction code is added to a video quantization coefficient bitstream in a convolution encoder 752 and a space time block code (STBC) encoder 756. At this time, not only the video quantization coefficient bitstream, but also other data streams mixed and encrypted in the bitstream MUX 73 pass through the bitstream processor.

TAIL Bits Inserter 751 adds a '0' as the last bit to receive input from the Convolution Encoder. The encoding rates for each encoder are 1/2, 3/4, 5/6, which can be selected differently depending on the radio state, such as 1/2 if the radio state is good and 5/6 if the radio state is not good. The bitstream passing through the convolutional encoder 752 evenly spreads adjacent bits in the bit interleaver 753. The symbol mapper 754 converts the video quantization coefficient bitstream into coefficients of the IQ quadrature phase in order to convert it into an analog signal. As shown in FIG. 15, the bitstream of the quantization coefficient stream is always coded with 16-QAM only. can do.

FIG. 15 is a diagram illustrating a 16QAM arrangement for converting into coefficients of an IQ quadrature phase of a quantization coefficient stream in an example of a DLPDU PHY structure of a WHDI active source device. FIG. In 16QAM, each of the four bit strings is converted into one symbol.

Next, FIG. 16 is a diagram illustrating an example of a process of parsing an OFDM symbol in a symbol parser in an example of the DLPDU PHY structure of the WHDI active source device.

The DLPDU symbol parser 725 sequentially distributes 16-QAM symbols for each subcarrier and spatial stream allocated to the quantization coefficient stream for the modulated symbol string.

Since DLPDU has a larger amount of transmission than uplink data (200Mbps or more in 1080p), a plurality of spatial streams are used. Referring to FIG. 16, the DLPDU Symbol Parser 725 converts an input sequence of an IQ complex signal into a vector such as an OFDM symbol, a subcarrier, and a spatial stream.

For example, suppose there are four MIMO channels, Nsym OFDM symbols, and Nscc subcarriers. Input data Complex 0, Complex 1,... , Complex T,… <OFDM symbol # 1, Subcarrier # 1, Spatial Stream # 1> <OFDM symbol # 1, Subcarrier # 1, Spatial Stream # 2> <OFDM symbol # 1, Subcarrier # 1, Spatial Stream # 3> < OFDM symbol # 1, Subcarrier # 1, Spatial Stream # 4> <OFDM symbol # 1, Subcarrier # 2, Spatial Stream # 1> <OFDM symbol # 1, Subcarrier # 2, SpatialStream # 2>. <OFDM symbol # 2, Subcarrier # 1, SpatialStream # 1> <OFDM symbol # 2, Subcarrier # 1, SpatialStream # 2>... <OFDM symbol # Nsym, Subcarrier # Nscc, SpatialStream # 3> <OFDM symbol # Nsym, Subcarrier # Nscc, Spatial Stream # 4>.

The STBC Encoder 756 shown in FIG. 14 adds redundant error correction codes for each spatial stream to further enhance error correction possibilities.

Next, a quantization error data processing and encryption process performed by the fine data processing and encryption module 76 will be described with reference to FIG. 17.

FIG. 17 is a diagram illustrating a quantization error data processing and encryption module in an example of a DLPDU PHY structure of a WHDI active source device.

The video quantization error data stream via video encoder 72 is first subjected to quantization error data scaling by a quantization error data processing and encryption module 76. A quantization error data scaling module 761 in which quantization error data scaling is performed applies different scaling factors depending on whether each video block grouped by 8x8 is type 0 or type 1. For example, the size of the video block of type 0 is multiplied by 1.75 for all included quantization error data, and the size of the video block of type 1 is multiplied by 1 for all included quantization error data.

Subsequently, the scaled video data is subjected to a symbol mapping process in the symbol mapper 762. The quantization error data modulation process is distinguished from general digital / analog modulation (BPSK, QPSK, QAM). First, one quantization error data stream is grouped into two quantization error data, for example, a quantization error for the Y component and a quantization error for the Chroma component in one pixel. After the quantization error data processing and encryption process are performed in two groups, one modulation symbol includes two quantization error data. The first quantization error data has a real value and the second quantization error data has an imaginary value. In the modulation process, the (±) code is used as it is before the modulation is performed, and the modulation is performed using a synthesis method of quadrature carriers. For example, if the size of IQ is ± 2047 and the maximum available value of the quantization error data is 1007.5, the first data is +22 and the second data is -24, and I = (22 * 2) + 32 = 76, Q = ( -24 * 2) + 32 = -80. This has the advantage that more than twice as much data can be represented in one symbol than the modulation scheme of the quantization coefficient data stream such as 16QAM or 64QAM. As such, when modulating the quantization error data in the active source device, one corresponding quantization error data element for the Y, Cb, and Cr components of one pixel is not decomposed into I and Q components. Instead, one quantization error data element is connected to the I component and the next quantization error data element is connected to the Q component.

Thereafter, the quantization error data encryptor 763 uses a modulated symbol as a complex input signal and encrypts the AES-128 CTR method according to a key set in the quantization error data encryptor. The encrypted complex output signal is distributed by fine-data scrambler 764 to avoid clustering errors.

Next, the MIMO-OFDM mapper 77 performs appropriate space time streams, subcarriers and OFDM symbols for quantization coefficient data complex value symbols, quantization error data complex value symbols, fixed pilots and varying values. Map the pilot. In addition, a specific subcarrier is allocated as a subcarrier for a fixed pilot and a variable pilot so that a receiver can perform time synchronization or channel measurement using the same.

The preamble MUX 783 then multiplexes between the preamble field and the other fields CES, BH, EH, IQ, and DATA to generate the entire DLPDU. When designing for the preamble field, the preamble is selected as an input signal. On the other hand, when designing for the other fields (CES, BH, EH, IQ, DATA), the output of the OFDM modulator is selected as the input signal.

The symbol shaper 784 performs to satisfy the spectral mask shown in FIG. 18.

18 is a diagram illustrating an example of a spectrum during DLPHY RF transmission in a WHDI active source device.

Overall transmitted baseband signal consists of all field contributions. Here, the following Equation 1 is satisfied.

는 각각

의 필터링된 버전이다. Symbol shaper(784)에서 산출되는 DLPHY 신호는 도 18에 도시된 바와 같은 Spectral Mask 최대치의 주파수 특성을 갖는다. here,

Respectively

Filtered version of. The DLPHY signal calculated by the symbol shaper 784 has a frequency characteristic of a spectral mask maximum as shown in FIG. 18.

Next, an uplink which is a period for transmitting a PHY signal from a sink device or a passive source device to an active source device in a WHDI system will be described.

As described above, the active source device is a source device that transmits video data or audio data to one or more devices, and the passive source device is a source device that is additionally connected to the active source device without transmitting video data. The sink device is also a device that receives video data or audio data from the active source device. The sink device described below is considered to include an active source device.

The uplink period in the PHY period is divided into a mode for generating an Uplink Independent PHY Data Unit (ULIPDU) and a mode for generating an Uplink Control PHY Data Unit (ULCPDU).

ULIPDU transmits a signal to announce its existence by circulating several channels inside the 5Ghz UNII band to search for a source device without a MAC connection, regardless of which source device is connected to the sink device. The ULCPDU is a PHY mode in which a wireless device connected to an active source device transmits a control signal to another device using a short time by avoiding a DLPDU, as described above with reference to FIG. 7.

In detail, the generation of the ULIPDU will be described with reference to FIGS. 19 to 23.

19 is a diagram illustrating an example of a form of transmitting a ULIPDU from a sink device to a source device in a WHDI system.

ULIPDUs are similar to Video Independent DLPDUs that are independent of video data and have a relatively long signal duration. The ULIPDU is performed by continuously transmitting a plurality of signals or by repeatedly transmitting a short idle period and receiving a response again. As shown in FIG. 19, for example, 8750 400 uS ULIPDU signals are transmitted for 3500 msec, and then wait for a signal response for 400 ms, and then transmit 8750 identical ULIPDU signal sets. That is, the group of sink devices of the _ULIPDU forms a single T _uli period and induces the response of the source device while traversing the 5 Ghz U-NII band frequencies such as Fuli [0] and Fuli [1], respectively.

20 is a block diagram illustrating a transmitting device for performing ULIPDU transmission in a WHDI system.

The transmitting device transmitting the ULIPDU includes a bitstream processor 81, an OFDM mapper 82, an uplink IDFT (downlink DFT) 83, a CP inserter 84, a preamble MUX 85, and a Symbol Shaper 86 And analog and RF module 87. Each component processes data only, not audio data or video data. The data transmitted through the ULIPDU includes a device ID (6 bytes value), an ID of a device to be searched for, a vendor ID, and the like.

In WHDI, each device in the addressing scheme has a unique ID. The device ID is a 6-byte MAC address that can identify each and every WHDI device. In general, assuming that the WHDI-HDMI bridge (adapter) is a basic device, the device attached to it (for example, DVD, STB, Blueray, etc.) is called a subdevice, and each 1 byte address of LSA (Logical Sub-Address) is designated. Add. When the network is connected, a 1 byte address called ANA (Active Network Address) is added to each WHDI device. In this way, each device can be distinguished based on a device address system composed of <device ID, LSA, ANA> pairs.

21 is a block diagram illustrating a bitstream processor of a transmitting device for performing ULIPDU transmission in a WHDI system.

가 된다. 변조된 심볼(복소수 신호)은 심볼 파서(812)를 통해 각각의 OFDM 심볼에 할당된다. 하나의 OFDM 심볼은 부반송파 개수만큼의 복소수 신호 입력을 할당할 수 있다. ULIPDU는 MIMO, STBC와 같은 다중 안테나 기술을 사용하지 않고 하나의 공간적 스트림, 공간 시간 스트림으로 전송된다. ULIPDU OFDM 의 부반송파의 개수는 DLPDU OFDM의 부반송파 개수보다 상대적으로 적다. 이는 데이터 레이트가 1080p이상의 비디오 데이터 전송을 위해 200Mbps 이상의 전송량이 필요한 것에 비해 제어 신호의 필요 데이터량이 1Mbps 이하로 적기 때문이다.Referring to FIG. 21, the ULIPDU bitstream processor 81 includes a symbol mapper 811 and a symbol parser 812. The ULIPDU data modulation performed by the symbol mapper 811 is performed using On-Off Keying (OOK). For example, if one phase carrier is used, the carrier size (strength) is 0 when the input bit is 0, and the carrier size (strength) is 1 when the input bit is 0.

Becomes The modulated symbol (complex signal) is assigned to each OFDM symbol via a symbol parser 812. One OFDM symbol may allocate as many complex signal inputs as there are subcarriers. The ULIPDU is transmitted in one spatial stream and space time stream without using multiple antenna technologies such as MIMO and STBC. The number of subcarriers of ULIPDU OFDM is relatively smaller than the number of subcarriers of DLPDU OFDM. This is because the required data amount of the control signal is less than 1 Mbps, while the data rate requires a transmission amount of 200 Mbps or more for video data transmission of 1080p or more.

Next, the OFDM mapper 82 maps a symbol and pilot of a data complex value to subcarriers and OFDM symbols. It is also possible to generate the pilot.

In the WHDI system, the ULIPDU DFT module 83 actually has a function of DFT / IDFT and operates as a DFT when receiving in downlink but as an IDFT when transmitting in uplink. That is, based on the sink device, the ULIPDU DFT module 83 operates as an IDFT when transmitting and as a DFT when receiving.

The ULIPDU CP Inserter 84 adds a cyclic period to the IDFT-transformed signal transmission process in order to avoid multi-path interference between the symbols before and after OFDM. The ULIPDU Preamble MUX 85 generates a ULIPDU by performing multiplexing between the preamble field, the CES, and the data. In the case of designing the preamble field, the preamble is selected as the input signal, whereas in the case of the design of CES and data, the signal output from the OFDM modulator is selected as the input signal.

Subsequently, symbol shaping is performed in the ULIPDU symbol shaper 86 to satisfy a spectrum as illustrated in FIG. 22. 22 is a diagram illustrating an example of a transmission spectrum when 20 Mhz in a WHDI ULIPDU.

Next, the ULCPDU in the uplink will be described with reference to FIGS. 23 to 25.

In general, PHYs are designed to provide robustness and flexibility to support data transfer rates up to 100 Kbps for optimal operation in homes or offices. In this case, various signal processing apparatuses including OFDM modulation and frequency diversity may be used. PHY transmissions can use 20 MHz bandwidth mode and 40 MHz bandwidth mode, with two bandwidth modes mandatory for all WHDI devices.

Sharing and co-existing media with other devices in the 5 GHz band is an important issue for maintaining high performance as avoiding interference to other systems. ULCPDU modulation is designed to coexist with other existing devices through a variety of means including carrier sense, automatic frequency selection, and transmission power control.

The ULCPDU is a period for transmitting data / control information using uplink from a sink device to a source device or a passive source device to an active source device in a PHY for WHDI wireless transmission. That is, the ULCPDU is a PHY signal sent by the sink device or passive source device to deliver a control message to another active source device, sink device, or passive source device after the sink device receives the DLPDU from the active source device. The sink device or passive source device discovers the active source device and then locks the channel and transmits a ULCPDU.

In this case, as shown in FIG. 23, ULCPDU transmission may be transmitted only for a short time between each DLPDU transmission period. FIG. 23 is a diagram illustrating a form of transmitting a video signal according to time between a DLPDU and an ULCPDU in a WHDI system. As described above, the PHY signal transmission in the WHDI uses the 5Ghz band.

24 is a block diagram illustrating a configuration of a transmitting device for transmitting an ULCPDU in a WHDI system.

A reference implementation of the ULCPDU baseband provides an RF signal as a reference to encode the input data / control bitstream.

The ULCPDU transmitting device is similar to the structure of the ULIPDU transmitting device described above in FIG. 21. Referring to FIG. 24, a Bitstream Processer 91 in which a process for processing an input data bitstream is performed, and an OFDM mapper 92 for dividing a processed signal into pilot and data modulation symbols and mapping the same to an OFDM symbol Uplink IDFT module 93 for converting one array point block to a time domain block, CP inserter 94 for adding a cyclic prefix to the modulated signal transmission, preamble field Preamble MUX 95 for different filters and multiplexing, Symbol Shaper 96 for shaping symbols in the time domain to implement the required spectrum, Frequency Corrector 97, and analog and RF modules Analog and RF module 98). Here, the frequency corrector 97 is a component included only in the ULCPDU transmitting device, unlike the ULIPDU transmitting device structure, and performs frequency pre-correction to correct a frequency offset between the transmitting device and the receiving device.

Specifically, the bitstream processor 91 includes a bitstream encryptor 911, a symbol mapper 912, and a symbol parser 913 as shown in FIG. 25. 25 is a block diagram illustrating a configuration of a bitstream processor in a ULCPDU transmitting device in a WHDI system.

The bitstream encryptor 911 encrypts the data bitstream using the AES-128 CTR method. As in the ULIPDU transmitter, the symbol mapper 912 modulates the encrypted data bitstream into a plurality of symbols in an on-off keying scheme. The symbol parser 913 then determines how many OFDM symbols each symbol is to be included.

Next, the frequency corrector 97 is implemented only in the ULCPDU transmitting device. In order to compensate for the frequency offset between the ULCPDU transmitter and the target ULCPDU receiver, it is applied before being transmitted through the analog and RF module 98.

The frequency compensation performed in the frequency corrector 97 is shown in Equation 2.

은 MAC 계층에 의해 설정되는데, 타겟으로 결정한 ULCPDU 수신기를 포함하는 소스 디바이스로부터 수신받은 DLPDU에서 추정될 수 있다. 구체적으로,

은 ULCPDU 송신기와 타겟으로 삼은 ULCPDU 수신기 간 주파수 오프셋이 보상 이후 1325Hz 미만이 되도록 설정된다. ULCPDU의 아날로그 및 RF 모듈(Analog and RF module; 98)에서는 수신측에서 발생하는 수신장애에 따라 반송파 주파수를 1325Hz까지 유동적으로 조정할 수 있다.here,

Is set by the MAC layer, which may be estimated in the DLPDU received from the source device including the ULCPDU receiver determined as the target. Specifically,

Is set such that the frequency offset between the ULCPDU transmitter and the targeted ULCPDU receiver is less than 1325 Hz after compensation. In the analog and RF module (98) of ULCPDU, the carrier frequency may be flexibly adjusted to 1325 Hz according to a reception error occurring at the receiver.

As described above, a source device for transmitting A / V data and a sinking device for receiving the A / V data among user devices belonging to the WHDI have been described in detail. In the device having the structure described above, when signal division, DFT modulation, and quantization are performed, A / V data is transmitted and received.

Hereinafter, a method of transmitting and receiving A / V data between user devices in WHDI will be described.

FIG. 26 is a diagram illustrating AVCL commands and corresponding response message exchanges for A / V data streaming between a transmitting device and a receiving device in WHDI.

In order to stream the A / V data, the transmitting device transmits an AVCL message or command to the receiving device prior to the connection between the devices (S101). Referring to FIG. 3 above, an AVCL message or command is generated in the AVCL 32 of the transmitting device.

The AVCL command message sent via the transmitting device may include the components shown in Table 1.

Field Name Description Size Value Initiator_Addr Initiator_AVCL_Address 2 Bytes Byte 0: Initiator Device_ANA
Byte 1: Initiator Device_LSA Follower_Addr
Follower AVCL_Address
2 Bytes Byte 0: Follower Device_ANA
Byte 1: Follower Device_LSA AVCL_Opcode Opcode 1 Bytes AVCL_Parameter Parameter (s) specific to opcode (Optional, depending on opcode) Depends on Opcode

Referring to Table 1, one AVCL command message may be composed of an AVCL_parameter as a transmitting device address (Initiator_Addr), a receiving device address (Follower_Addr), an AVCL_Opcode, and an identifier. As one or more devices included in the WHDI network need to be distinguished, a bit indicating an address of a transmitting device and a receiving device needs to be added in order to meet the above-described device address scheme. The sender address (Initiator_Addr) is the address of the sender that transmits the AVCL command. The sender address (Initiator_Addr) has a size of 1 byte indicating ANA (the address given by the active source device when the sending device is the active source device) and 1 byte indicating the LSA. Have The receiving device address Follower_Addr is a network address of the receiving device that receives the AVCL command. Similarly, the receiving device address (Follower_Addr) has a size of 2 bytes by allocating 1 byte to the ANA and the LSA.

AVCL_Opcode represents a variety of commands by type of message, which are listed in Table 2.

Command Opcode Command Opcode Command Opcode Command Opcode <Action Reject> <Record On> <EDID Request> <System Audio Mode Request> <Action Accept> <Record Off> <EDID Status> <System Audio Mode> <Wait> <Record Status> <EDID Report> <Audio Control> <Get LSAs> <Record Display> <Get Subdevice Information> <Give Audio Volume> <Report LSAs> <Clear Analog Timer> <Report Subdevice Information> <Report Audio Volume> <Get LSA from OSD Name> <Clear Digital Timer> <Set Subdevice OSD Name> <Set Audio Display> <Report LSA from OSD Name> <Clear External Timer> <Give Deck Status> <Audio Display> <Active Stream Source> <Set Analog Timer> <Deck Status> <Get Audio Display> <Inactive Stream Source> <Set Digital Timer> <Deck Control> <Present OSD String> <Set Active Stream Source> <Set External Timer> <Play> <Present OSD Menu> <Request Active Stream Source> <Set Timer Program Title> <Give Tuner Device Status> <OSD Menu Current Selection> <Switch Stream Source> <Timer Cleared Status> <Tuner Device Status> <OSD Menu Final Selection> <AV Status> <Timer Status> <Select Analog Service> <Present OSD Text Request> <Get AV Status> <User Control Pressed> <Select Digital Service> <OSD Text Response> <Menu Request> <User Control Released> <Tuner Step Decrement> <Get OSD Language> <Menu Status> <User Control Still Pressed> <Tuner Step Increment> <Report OSD Language> <Device Setup> <Standby> <Vendor Command> <Image View On> <Text View On>

Referring to Table 2, various types of AVCL messages may be exchanged between the transmitting and receiving devices. Here, the 'command opcode' is AVCL_Opcode, which indicates the command requested by the transmitting device to the receiving device and the response message that can be responded according to the requested command.

When the AVCL command transmitted in step S101 is a command for requesting an action, when the receiving device that has received the command cannot perform the requested action or is not ready for action, it sends a response message to the transmitting device. In operation S102, the AVCL_Opcode of the response message transmitted by the receiving device may indicate an action reject message among a plurality of commands shown in Table 2 below.

The action reject message is a message responding to the transmitting device when the receiving device cannot perform the requested action, and may include a reason code including information related to the reason for rejecting the action as the AVCL_ parameter. Reason codes are described with reference to Table 3.

Table 3 shows the action reject message, action accept message, and wait message in response to the action request message received by the receiving device when transmitting the action request message AVCL_ message from the transmitting device to the receiving device. Indicates parameters included in the message. In the AVCL message transmission according to an embodiment of the present invention, a reason code is further added as an AVCL parameter.

Command Opcode Params Param Length
[ Byte ] Params Options Addressing Response <Action Reject> [Rejected Opcode] One Initiator and Follower swapped from rejected command No response [Rejected Reason] One 0 × 00_Un-specified 0 × 01_Unrecognized Command 0 × 02
_Invalid Parameter 0 × 03_Command not supported 0 × 04_Cannot perform action at this time 0 × 05_vender not supported 0 × 06_User rejection 0 × 07_No A / V Stream available 0 × 08_Mandatory parameter is missing 0 × 09_Host is in standby mode 0 × 0A_EDID not supported 0 × 11_System shut down 0 × 12_0 × FF <Action Accept> [Accepted Opcode] One Initiator and Follower swapped from accepted command No response <Wait> [Deferred Opcode] One Initiator and Follower swapped from received command No response

Referring to Table 3, the action reject message is a message used as a response when the sink device receiving the message cannot process the requested content for the AVCL message request sent by the source device. The action reject message may include two parameters, [Rejected Opcode] and [Rejected Reason]. [Rejected Opcode] specifies an OPCODE indicating that a message type that cannot be processed as 1 byte is an action reject, and [Rejected Reason] also allocates 1 byte and indicates a reason why the action request received by the receiving device is impossible.

The action accept message in Table 3 indicates that the response processing is completed, and the source device may or may not transmit the message to the sink device. Wait message means that if the sink device requests A / V data transmission to the source device, etc., if the source device does not have time to process the message after receiving the request message, for example, wait 500 ms. As a message, it is a response message for transmitting a message corresponding to [Deffered Opcode] to the sink device. Even when the source device transmits the standby message to the sink device, the reason code cannot be processed as in the action reject message can be indicated by the reason code, which will be described with reference to Table 4 below.

In the above Table 3, the (0 × 0 to 0 × 12) codes generally classify and parameterize the cases that cause the sink device receiving the action request message from the source device to transmit the action reject message. .

The 0x0 parameter indicates a <Un-specified Command> message if the rejection reason of the sink device is not specified or unknown. The 0 × 1 parameter indicates an <Unrecognized Command> message that the command is not recognized if the received command OPCODE is not defined in SPEC. The 0x2 parameter indicates the message <Invalid Parameter>, which is an invalid command if the OPCODE of the message received from the transmitting device is not defined on the SPEC even if it is supported by the receiving device.

The 0 × 3 parameter indicates a <Command not supported> message even when a legal command not defined in the SPEC does not support the received command by the receiving device receiving the action request message. The 0 × 4 parameter is a case where the receiving device receiving the action request message is rejected because the receiving device cannot simultaneously execute the requested action and indicates a <Cannot perform action at this time> message. The 0x5 parameter indicates a <Vender not supported> message when the receiving device that receives the control command specified by the vendor does not support the command requested from the specified vendor. The 0x6 parameter indicates a <User rejection> message that the user refuses to execute the requested commander, for example, when the function according to the received command is not available or when the request message is received.

The 0x7 parameter is then included in the message that the source device responds to in response to the <Set Active Stream Source> command. That is, if the source device receiving the A / V streaming request from the sink device does not want to transmit the A / V stream to the active source device or the A / V stream cannot be transmitted because the audio or video output is not prepared, the sink device is sent to the sink device. Indicates an action reject message that can be sent.

The 0x8 parameter indicates a <Mandatory Parameter is missing> message that transmits an action reject message as an error code when a parameter to be requested is not included in a command received by the receiving device. The 0x9 parameter indicates the message <Host is in standby mode> when the host device of the receiving device is in a low power state in standby mode when receiving a request message from the transmitting device, so that immediate processing of the request is difficult. . The 0 × 10 parameter indicates the message <EDID not supported> when the sink device does not have EDID information when the sink device receives EDID information from the source device. The 0 × 11 parameter indicates a <Host is busy> message that is used when the usage rate of the host control unit of the receiving device is increased and processing of the received request message is not possible. The 0 × 12 parameter indicates a <System shut down> message for rejecting a request message from the transmitting device while the system of the receiving device is currently stopped.

Hereinafter, embodiments of transmitting the above-described AVCL_parameter in the message exchange between the WHDI devices according to the present invention will be described with reference to FIGS. 27 and 28.

FIG. 27 is a diagram illustrating a process of transmitting, by a sink device, a response message to a source device when the WHDI source device requests EDID information from the sink device according to one embodiment of the present invention.

In the step of starting the A / V streaming between the source device and the sink device, the source device may transmit an EDID request message through the DLPDU to request Extended Display Identification Data (EDID) information for the sink device (S201). Here, the EDID information is a standard for delivering display information from the display side to the host side and is a data type for transferring the capability of the display to the host. In WHDI, the display side is seen as the source device and the host as the sink device.

0 × 11 parameter indicating <System shut down> message when the sink device receiving the <EDID Request> message requesting EDID information from the source device is shutting down the system such as turning off the power when receiving a button request from the user. The action reject message including a may be transmitted to the source device (S201). At this time, a response message is transmitted from the sink device to the source device using the ULCPDU. Accordingly, the source device may know that the requested action is denied because the source device is turned off rather than denied because the EDID is not present in the sink device through the AVCL parameter included in the received response message. In addition, by not making a false assumption that the sink device does not have an EDID, errors that may occur in connection or signal transmission and reception between devices can be prevented.

28 illustrates a process of transmitting a response message from a source device to a sink device when the WHDI sink device transmits an <A/V Status> message to the source device to start A / V streaming according to another embodiment of the present invention. It is a figure which shows.

Referring to FIG. 28, the sink device may transmit a <A/V Status> message for requesting an A / V streaming connection to a source device (S301). When the A / V streaming connection request source device does not output an audio signal or a video signal, the source device may transmit an action reject message including a 0 × 7 parameter indicating a <No A / V stream available> message to the sink device. (S302). In this case, the sink device knows that there is no video output from the source device, so wait until the video output comes out upon re-request, or use a separate vendor-specific message to check if the video output is coming from the source device and reconnect the connection. You can try

Next, a case in which the receiving device receiving the message requesting A / V streaming from the transmitting device transmits a wait message to the transmitting device in response thereto will be described with reference to Table 4 below.

As described above, the transmitting device transmitting the request message may be a source device or a sink device, and the receiving device transmitting the response message to the request message may be a sink device or a source device.

The receiving device, which has received the AVCL_command from the transmitting device, may transmit a response message indicating the waiting message to the transmitting device in AVCL_Opcode. Alternatively, the receiving device may transmit a waiting message to the transmitting device even if the AVCL command is not requested from the transmitting device, and may proactively transmit the waiting message to the transmitting device when the status of the receiving device is difficult to accept a new request.

In the following description, for example, when the sink device transmits a <A/V status> command to the source device for A / V stream connection, the source device transmits a standby message to the sink device. Do it. Table 4 shows wait messages including wait response parameters.

Command Opcode Params Param Length
[ Bytes ] Params Options Addressing Response <Wait> [Defferd Opcode] One If 0 × FF, all commands shall be deferred Initiator and Follower swapped from rejected command No response [Wait Time]
Wait Reason One One 0 × 00_Un-specified 0 × 01_Video is not ready 0 × 02_Audio is not ready 0 × 03_System is starting-up 0 × 04_Host busy

Referring to Table 4, a source device generally includes a 0 × FF code including a <all commands shall be deferred> message with [Deferred OPCODE] when processing for AVCL_Opcode received from the sink device is delayed. Send a response message. Conventionally, a response message including a 0 × FF code including a <all commands shall be deferred> message as a standby message is transmitted to the sink device regardless of the cause of the delay of the source device.

According to an embodiment of the present invention, the waiting message may include a [WaitTime] parameter and a [WaitReason] parameter in the [Deferred OPCODE]. Here, the [WaitTime] parameter is 1 byte, and the delay time of the source device can be described up to 2.55 seconds in 10 ms units, which is more accurate than in the case of the conventional 500 ms unit, and can wait to minimize the delay.

Next, the [WaitReason] parameter is for identifying the cause of delay in processing a message requested by the source device to the sink device, and may transmit more accurate delay information to the sink device or the user. The 0 × 0 parameter in the [WaitReason] parameter indicates a <Un-Specified> message when the sink device is not specified or unknown. The 0 × 1 parameter indicates a <Video not ready> message when the source device is delayed because it cannot output a video signal or is not ready to display an image on the screen. The 0 × 2 parameter indicates a <Audio not ready> message when the source device fails to output audio or the sink device is delayed because audio is not ready to be output to the speaker. The 0 × 3 parameter indicates a <System is starting up> message when the sink device should wait because the system is booting when the source device receives the request message. The 0 × 4 parameter indicates the message <Host busy> when the host processor that is the master of the source device in the WHDI system is slow and cannot process the request.

FIG. 29 is a diagram illustrating a process of transmitting a standby message to a sink device by a source device that is requested to transmit A / V data from the sink device according to one embodiment of the present invention.

Referring to FIG. 29, the source device may transmit a standby message to the sink device through the DLPDU even if a request message is received or not received from the sink device (S401). At this time, the wait message includes three pieces of information about the source device. The OPCODE indicates that all commands cannot be received with a 0 × FF code. In addition, the [WaitTime] parameter indicates a delay time of 100 ms, that is, 1 second, which instructs the sink device receiving the wait message to wait for 1 second. The [WaitReason] parameter indicates a <System is starting up> message with a 0 × 3 code, which may indicate that the source device is currently booting the system and thus does not receive A / V streaming requests from the sink device.

On the other hand, when the source device is ready to accept the request prior to the delay notice in advance may transmit a <System Ready> message to the sink device via the DLPDU may indicate that the message is ready to process (S402). In this case, the sink device receiving the <System Ready> message may reduce the processing delay time by transmitting and recovering the <AV Status> message faster through the ULCPDU to the source device (S403). In contrast to sending a <System Ready> message, the source device continuously sends a Wait command to the sink device if it is delayed longer than the previously announced delay or longer than 2.55 seconds (2550ms). Can transmit

As described above, message exchange between WHDI devices may be used as a sink device of a WHDI wireless network as a message exchange for switching of a source device.

30 is a diagram illustrating an example of a WHDI network configuration.

Referring to FIG. 30, one active source device 110 may broadcast A / V data to sink device 1 120 and sink device 2 130 using DLPDU. The active source device 110 stores the device ID (6 bytes) of each device and uses the device ID when transferring the device list to another device.

Meanwhile, the passive source device 140 may receive only an uplink signal from the sink device 1 or the sink device 2 and decode it into data. In addition, the ULCPDU may be used to deliver a message to the active source device 110. Therefore, the transmission path of the control message corresponds to the L1, L2, L3, L4, L5 paths between the nodes of the active source device 110, the sink device 1 120, the sink device 2 130, and the passive source device 140. do.

In general, one WHDI network transmits a DLPDU only by an active source device, and the other WHDI source device cannot decrypt the DLPDU. Therefore, when transmitting a control message such as “remote control path through” from the active source device 110 to the passive source device 140, it must pass through the sink device 1 120 or the sink device 2 130. That is, it should be transmitted to multiple radio paths including several radio paths such as paths <L1, L4> including paths L1 and L4, but paths <L2, L3> including paths L2 and L3.

Meanwhile, the sink device receiving the A / V data from the source device can switch from the currently connected source device to another source device located on the network, which will be described with reference to FIGS. 31 and 32.

31 is a diagram illustrating a path for transmitting a message between devices on a WHDI network.

FIG. 31 illustrates various paths using DLPDUs and ULCPDUs for MAC message transmission between an active source device, a passive source device, and a plurality of sink devices in the aforementioned WHDI network of FIG. 29. The active source device 110 may transmit a radio signal via DLPDU simultaneously or sequentially to at least one or more sink devices 120 and 130 included on the WHDI network. Sink devices 120 and 130 may also transmit radio signals via ULCPDU to active source device 110 and passive source device 140. As described above, the radio signal includes a MAC message or A / V data or the like including the AVCL command.

As described above with reference to FIG. 30, direct message exchange is possible between the active source device 110 and the sink device 1 120 such as the path 1 and the path 2. Although not shown in FIG. 31, direct message exchange between the active source device 110 and another sink device 130 is also possible. However, the passive source device 140 may not directly transmit a signal to the sink devices 120 and 130, but must transmit the signal through the active source device 110 as in the path 3. In addition, even when the sink device 1 120 transmits a signal to the other sink device 130, the signal must be transmitted as the path 5 via the active source device 110.

In this case, the sink device may switch the connected source device to another source device, which will be described with reference to FIG. 32.

32 is a diagram illustrating a process of transmitting a message to switch a source device to which a sink device is connected according to another embodiment of the present invention.

For example, referring to FIG. 32, the sink device 1 120 is currently receiving A / V data from the active source device 110 through the DLPDU (S501).

When the source device connected to the sink device is to be switched from the active source device 110 to the passive source device 140, the sink device 1 generates an action request message including a <Set Active Stream Source> message with an AVCL command. In the interval, it may be transmitted to the passive source device through the ULCPDU (S502).

Here, the AVCL command is generated in the AVCL 32 of the sink device of FIG.

The source device and the sink device may exchange AVCL commands or messages with each other, substantially exchange messages, data, and the like through the PHY layer 34 of each device. For example, if the sink device wants to send an AVCL request message from the sink device to the passive source device as shown in FIG. 32, the AVCL request from the sink device's AVCL 32 via the MAC layer 33 to the passive source device through the PHY layer 34. Send a message.

Referring to FIG. 2, a broadcast signal receiving system including a broadcast signal receiver 21 as an example of a transmission device generates a signal including an AVCL request message from the network control module 216 and inputs the signal to the receiver 211. The external broadcast signal may be transmitted to the reception device 25. In addition, a radio signal including an AVCL command may be received in response to the AVCL request message generated by the reception device 25. Hereinafter, a signal processing process performed by the network control module 216 will be described.

Referring to FIG. 3, all AVCL commands generated at the AVCL 32 of the sink device are sent to the MAC layer 33 to be mapped to the MAC message in an equivalent type. The <Set Active Stream Source> message, which is a kind of AVCL command according to an embodiment of the present invention, is also transmitted from the AVCL 32 to the MAC layer 33. The MAC message of the MAC layer 33 is substantially a medium for transferring information between WHDI devices, and the type and length of the MAC message may be variously set according to each AVCL command.

33 is a diagram illustrating an example of a MAC message form generated at the MAC layer 33 in a transmitting device. The MAC message may be classified into a relatively short MAC message and a long MAC message according to whether the Null field is included. The MAC message illustrated in FIG. 33 is a short MAC message excluding the Null field. The null field is an area allocated for transmitting a null message and has a length of 1 byte, and has a value of 0 × 00.

Referring to FIG. 33, a short MAC message includes a 16-byte long 2 byte MAC message preamble, a bit indicating a 2 byte MAC message type, a 1 byte MAC message length, a variable length MAC message body, and a 16-bit CRC. It includes a 16-bit message check sequence (MCS) field. Here, the MAC message body field may use various lengths from 1 bit to 254 bits according to the AVCL command. That is, when the AVCL command is transmitted from the transmitting device to the receiving device, the AVCL command is included in the MAC body field of the MAC message of the transmitting device and transmitted. According to an embodiment of the present invention, the <Set Active Stream Source> message, which is a kind of AVCL command, is included in the MAC body field and transmitted to the passive source device.

The MCS field may be calculated on all fields of the MAC message except the preamble field, message type, message length, and message body field of the message. Long length MAC messages contain a Null field.

As such, the MAC message containing the AVCL command generated at the AVCL 32 of the sink device is delivered to the PHY layer 34 and transmitted to the passive source device via the ULCPDU.

FIG. 34 is a diagram illustrating a format in which a MAC message including an AVCL command is transmitted from a sink device to a source device through a ULCPDU according to an embodiment of the present invention.

Referring to FIG. 34, a ULCPDU generally includes a preamble, a CES, an uplink control header (ULCH), and a data field for transmitting a data / control bitstream. The AVCL command, which is an action request message included in the MAC message, may be included in the data field for transmitting the data / control bitstream of the ULCPDU and transmitted from the sink device to the active source device or the passive source device. In FIG. 32, the AVCL command is transmitted from the sink device to the passive source device using the ULCPDU. The transmission method through the ULCPDU targets only data that is not related to A / V data. The AVCL command, which is an action request message, is not mixed with A / V data as shown in FIG. 20. In 81, the radio signal is modulated. The data bitstream including the modulated response message is mapped to the OFDM symbol through the OFDM mapper 82, and symbolized with the preamble added by the preamble MUX 85 through the IDFT transformation 83 and then RF. Is transmitted to the source device via module 87.

Next, in FIG. 32, the passive source device receives an ULCPDU including its AVCL command sent from the sink device at its PHY layer 34 and passes the AVCL command to the AVCL 32 via the MAC layer 33. . The AVCL 32 of the passive source device generates a response message in response to the <Set Active Stream Source> command received from the sink device. The response message may include a sending device address, a receiving device address, an AVCL_Opcode and an identifier. At this time, the host controller of the passive source device determines an AVCL_Opcode indicating an action accept message, an action reject message, or a waiting message according to whether the action requested by the sink device can be performed, and the reason code is determined using the AVCL_ parameter. Include.

The passive source device that has received the action request message of the <Set Active Stream Source> command from the sink device in step S502 cannot operate or does not want to be the second active source device to the user if it does not want to act as the active source device. In order to inform the information, the AVCL 32 generates an action reject message as a response message. The action reject message may include a reason code as an error code that specifies a reason why connection between devices is impossible. For example, the 0x07 parameter that means <No A / V stream available> among the various reason codes described in Table 3 may be included in the action reject message as a reason code.

If the current passive source device cannot or cannot act as an active source device, the action reject message containing the reason code of <No A / V stream available> generated in the AVCL 32 of the passive source device is a MAC layer ( 33) and transmitted to the active source device through the ULCPDU in the vertical blanking period interval as described above in Figure 33 (S503). The passive source device cannot send a response message directly to the sink device as described above. Accordingly, first, the passive source device transmits a response message to the active source device through the ULCPDU in the vertical blanking period (S503), and the active source device transmits the response message received from the passive source device to the sink device through the DLPDU. In operation S504, message exchange between the passive source device and the sink device is enabled. That is, the active source device is an intermediate medium for transmitting a message from the passive source device to the sink device.

Step S503 is performed via the ULCPDU in the same manner as the sink device sent the <Set Active Stream available> command to the passive source device in step S502. That is, in the same manner as in FIG. 34, the active source device transmits the MAC message including the AVCL message of the <No A / V stream available> command received from the passive source device to the sink device by including it in the data field of the ULCPDU.

In the case of step S504 of transmitting a message from the active source device to the sink device, the DLPDU is used with reference to FIGS. 35 and 36.

35 and 36 are diagrams illustrating a WHDI active source device transmitting a MAC message to a sink device.

Referring to FIG. 35, when an MAC message is transmitted from an active source device to a sink device, the MAC message is transmitted through a DLPDU, wherein a plurality of MAC messages of the active source device are allocated at least one on a plurality of frames, and each PHY unit is assigned to each frame. A DLPDU is configured at layer 34 and sent to the sink device. Some of the plurality of MAC messages include an AVCL message generated as a response message including an AVCL command received from a passive source device.

The DLPDU includes a header section consisting of a preamble, a CES, a basic header (BH) and an extended header (EH), an IQ section, and a section for transmitting a data / control bitstream. The MAC message may be transmitted as being included in the control bitstream in the data field for transmitting the data / control bitstream of the DLPDU.

Referring to FIG. 9, the data / control bitstream and the test bitstream that have not been subjected to the encoding process, the encoded audio bitstream, and the video quantization coefficient bitstream are converted into one bitstream in the bitstream MUX 73. Are mixed. That is, the MAC message including the <No A / V stream available> command in response to the <Set Active Stream Source> command is included in the control bitstream and mixed with other data streams in the WHDI PHY layer. (Coarse Stream Encryptor; 74). Thereafter, the signal is transmitted to the sink device through the RF module through the signal transmission process described above with reference to FIG. 9.

Meanwhile, when the active source device transmits the MAC message to the sink device through the downlink, the active source device may transmit not only through the data field of the above-described DLPDU but also use an extended header (EH) period.

36 is a diagram illustrating a format in which a MAC message is included in an extension header (EH) and transmitted when an MAC message is transmitted from an active source device to a sink device through a DLPDU.

The <No A / V stream available> command, which is a response message for the <Set Active Stream Source> command included in the extended header (EH) of the DLPDU, is also mixed, encrypted, and modulated in the WHDI PHY together with other bitstreams as shown in FIG. It is transmitted to the sink device through the process.

32, step S501 uses path L2, step S502 uses path L3, step S503 uses path L5, and step S504 uses path L2. That is, a single path may be used to transmit a signal from a sink device to a passive source device, but in the opposite case, multiple paths of <L5 and L2> should be used.

Next, the sink device may determine whether to disconnect the active source device being connected and switch to the passive source device according to the response message type transmitted from the passive source device.

As shown in FIG. 32, when the sink device receives an action reject message from the passive source device, the host processor of the sink device determines to maintain a current connection with the active source device. That is, an action reject message including an error code such as a <No A / V stream available> command when the passive source device that receives the <Set Active Stream Source> command from the sink device cannot or cannot operate as an active source device. When responding to the low sink device, the A / V data is continuously received from the currently connected active source device (S505).

On the other hand, when the passive source device that receives the <Set Active Stream Source> command from the sink device responds to the sink device with an action accept message, the host processor of the sink device disconnects from the active source device currently connected and passive. You can switch to the source device.

The terms used above may be replaced with others. For example, the device can be changed to a user device (or appliance), a station, etc., and the coordinator is a coordinator (or control) device, coordinator (or control) device, coordinator (or control) station, coordinator ), PNC (piconet coordinator) and the like can be used. Alternatively, an AVCL command for transmitting and receiving between devices may be used in the same meaning as an AVCL message. That is, the echo request / report message can be viewed as an echo request / report command.

In addition, in the above embodiment, the technical features of the present invention have been described based on the examples applied to the WVAN, but the technical features of the present invention are applicable to a peer-to-peer communication system or another wireless network system. Do.

The above embodiments are those in which the components and features of the present invention are combined in a predetermined form. Each component or feature is to be considered optional unless stated otherwise. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to combine some of the components and / or features to form an embodiment of the invention. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is also evident that the claims may be incorporated into claims that do not have an explicit citation in the claims, or may be incorporated into new claims by post-application correction.

Embodiments according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of a hardware implementation, embodiments of the invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), and FPGAs (fields). programmable gate arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc. that performs the functions or operations described above. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.

According to the present invention, a signaling process for establishing a connection between devices for transmitting A / V data in a wireless network can be simplified.

Those skilled in the art to which the present invention described above belongs will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, the above-described embodiments are to be understood as illustrative in all respects and not as restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

1 is a diagram illustrating an example of a user device configuring a WVAN.

2 is a diagram illustrating an embodiment of a broadcast signal processing system including a broadcast signal receiver as an example of a transmission device in a WHDI system.

3 is a diagram illustrating an example of a protocol hierarchy implemented in a device in a WHDI system.

4 is a block diagram illustrating an example of a source device in a WHDI system.

5 is a diagram illustrating an example of a sink device in a WHDI system.

FIG. 6 illustrates a process of converting a general video signal including a vertical blanking period into an RF signal in a WHDI device in A / V transmission / reception operation over time.

7 is a diagram illustrating an example of a DLPDU sequence in a video independent DLPDU mode in a WHDI PHY layer.

8 is a diagram illustrating an example of a DLPDU sequence in a video dependent DLPDU mode in a WHDI PHY layer.

9 is a diagram illustrating an example of a PHY structure for transmitting a DLPDU in a WHDI system.

10 is a diagram illustrating a structure of an audio encoder in an example of the DLPDU PHY structure of the WHDI active source device.

11 is a diagram illustrating a structure of a video encoder in an example of a DLPDU PHY structure of a WHDI active source device.

FIG. 12 is a diagram illustrating an example of block interleaving performed by the video encoder illustrated in FIG. 11.

FIG. 13 is a diagram illustrating quantization bits calculated per video block in a DLPDU PHY structure of a WHDI active source device. FIG.

14 is a diagram illustrating a bitstream processor in one example of a DLPDU PHY structure of a WHDI active source device.

FIG. 15 is a diagram illustrating a 16QAM arrangement for converting into IQ quadrature coefficients of a quantization coefficient stream in an example of a DLPDU PHY structure of a WHDI active source device. FIG.

FIG. 16 illustrates an example of a process of parsing an OFDM symbol in a symbol parser in an example of a DLPDU PHY structure of a WHDI active source device.

FIG. 17 is a diagram illustrating a quantization error data processing and encryption module in an example of a DLPDU PHY structure of a WHDI active source device.

18 is a diagram illustrating an example of a spectrum during DLPHY RF transmission in a WHDI active source device.

19 is a diagram illustrating an example of ULIPDU transmission from a sink device to a source device in a WHDI system.

20 is a block diagram illustrating a transmitting device for performing ULIPDU transmission from a WHDI system to a receiving device.

21 is a block diagram illustrating a bitstream processor of a transmitting device for performing ULIPDU transmission in a WHDI system.

22 is a diagram illustrating an example of a transmission spectrum when 20 Mhz in a WHDI ULIPDU.

FIG. 23 is a diagram illustrating a video dependent timing relationship between a DLPDU and an ULCPDU in a WHDI system. As described above, the PHY signal transmission in the WHDI uses the 5Ghz band.

24 is a block diagram illustrating a configuration of an ULCPDU transmitting device in a WHDI system.

25 is a block diagram illustrating a configuration of a bitstream processor in a ULCPDU transmitting device in a WHDI system.

FIG. 26 is a diagram illustrating AVCL commands and corresponding response message exchanges for A / V data streaming between a transmitting device and a receiving device in WHDI.

FIG. 27 is a diagram illustrating a process of transmitting, by a sink device, a response message to a source device when the WHDI source device requests EDID information from the sink device according to one embodiment of the present invention.

28 is a process for transmitting a response message from a source device to a sink device when the WHDI sink device transmits an <A/V Status> message to the source device to start A / V streaming according to another embodiment of the present invention; It is a figure which shows.

FIG. 29 is a diagram illustrating a process of transmitting a standby message to a sink device by a source device that is requested to transmit A / V data from the sink device according to one embodiment of the present invention.

30 is a diagram illustrating an example of a WHDI network configuration.

31 is a diagram illustrating a path for transmitting a message between devices on a WHDI network.

32 is a diagram illustrating a process of transmitting a message to switch a source device to which a sink device is connected according to another embodiment of the present invention.

33 is a diagram illustrating an example of a MAC message type present in the MAC layer 33 in the transmitting device.

FIG. 34 is a diagram illustrating a format in which a MAC message including an AVCL command is transmitted from a sink device to a source device through a ULCPDU according to an embodiment of the present invention.

35 is a diagram illustrating a format in which a WHDI active source device includes a data field when transmitting a MAC message to a sink device.

FIG. 36 is a diagram illustrating a format in which an WHDI active source device includes an extended header (EH) period when transmitting a MAC message to a sink device.

Claims (23)

In the message exchange method for the switching of the source device in the sink device of the wireless network, Receiving audio / video (A / V) data from a first source device; Sending a first command to the second source device to confirm that a second source device in the wireless network can transmit A / V data; A second command transmitted from the first source device by the second source device in response to the first command and including indication information indicating whether the second source device can transmit A / V data; Receiving; And And determining whether to switch to the second source device according to the indication information included in the second command. The method of claim 1, And the indication information included in the second command indicates that the second source device does not want or cannot transmit A / V data to the sink device. 3. The method of claim 2, The A / V data received from the first source device is included in a first downlink physical layer data unit (DLPDU: Downlink PHY Data UNIT), characterized in that the message exchange method. The method of claim 3, wherein And wherein the first command is included in an uplink control PHY data unit (ULCPDU) and transmitted to the second source device. The method of claim 4, wherein And wherein the second command is included in a second DLPDU and received from the first source device. The method of claim 4, wherein The first downlink physical layer data unit, A first time interval in which the MAC message and the at least one header are transmitted; And And transmitting during the time interval including a second time period during which the A / V data is transmitted. The method of claim 6, And the uplink control physical layer data unit is transmitted during the first time interval. The method of claim 5, The second command is multiplexed with A / V data transmitted from the first source device and included in the second DLPDU. The method of claim 5, The second DLPDU includes a basic header and an extended header, and the second command is included in the extended header. The method of claim 4, wherein The step of transmitting the first command to the second source device, And including a first identifier for identifying the transmitting device from an audio video control (AVC) layer in a medium access control (MAC) layer, a second identifier for identifying the receiving device, and an operation code (Opcode). Receiving a first command; Constructing a MAC message including a message preamble, a message type, and the first command in the MAC layer and delivering the MAC message to a physical layer; And Transmitting, at the physical layer, the uplink control physical layer data unit including an uplink control header, the MAC message, and audio / video (A / V) data to the receiving device; How to exchange messages. The method of claim 10, The MAC message is multiplexed with the A / V data in the physical layer. The method of claim 10, And the MAC message includes a Cyclic Redundancy Check (CRC) code added at the MAC layer for error detection at the receiving device. A sink device for receiving A / V data from a first source device in a wireless network, the sink device comprising: An Audio Video Control (AVC) layer for generating a first command comprising a first identifier for identifying the sink device, a second identifier for identifying a second source device, and an operation code; A Medium Access Control (MAC) layer for generating a MAC message including a message preamble, a message type and the first command received from the AVC layer; And A first physical layer data unit including an uplink control header, the MAC message, and audio / video (A / V) data is generated and transmitted to the second source device, and transmitted to the second source device. And a second physical layer data unit transmitted in response to the first command, the second physical layer data unit including a second command including indication information indicating whether the second source device can transmit A / V data. Physical layer receiving from the source device, And the sink device determines whether to switch to the second source device according to the indication information included in the second command. The method of claim 13, Receiving the A / V data from the first source device when the indication information included in the second command indicates that the second source device does not want or cannot transmit A / V data to the sink device; A sink device, characterized in that. 15. The method of claim 14, And the first physical layer data unit is an uplink control physical layer data unit (ULCPDU). The method of claim 15, And the second physical layer data unit is a downlink physical layer data unit (DLPDU). The method of claim 16, The DLPDU is transmitted during a time interval including a MAC message and a first time interval in which at least one header is transmitted and a second time interval in which A / V data is transmitted. And the ULCPDU is transmitted during the first time interval in which a portion of the DLPDU is to be transmitted. The method of claim 16, Wherein the second command is multiplexed with A / V data transmitted from the first source device and included in the DLPDU. The method of claim 17, And the at least one header includes a basic header and an extended header, and the second command is included in the extended header. In the sink device of a wireless network, A receiver which receives a broadcast signal from a first source device; A decoding unit for decoding the broadcast signal received by the receiving unit; A display unit which displays the content according to the broadcast signal decoded by the decoding unit; Generating a first physical layer data unit including a broadcast message received by the receiver and a MAC message including a first command for confirming whether the second source device can transmit A / V data to a second source device; A network control module for transmitting and receiving a second physical layer data unit from the first source device, the second physical layer data unit including a second command transmitted by the second source device in response to the first command; And Determine whether to switch to a second source device through the second command processed by the network control module, or control the receiver to store the received broadcast signal in a local storage device or to play content stored in the local storage device. A sink device comprising a control unit. The method of claim 20, And the second command includes indication information indicating whether the second source device can transmit A / V data. A message exchange method for switching a source device of a sink device from a first source device in a wireless network, the method comprising: In response to a first command sent from the sink device receiving audio / video (A / V) data from a second source device in an AVC layer, whether the first source device is capable of transmitting A / V data. Generating a second command including indicating indication information; Constructing and transmitting a MAC message including a message preamble, a message type, and the second command received from the AVC layer to a physical layer in a MAC layer; Transmitting, at the physical layer, a physical layer data unit including at least one header, the MAC message and audio / video (A / V) data through the second source device to the sink device; And Causing the sink device to determine whether to switch to the first source device according to the indication information included in the second command. A source device for receiving a first command from a sink device in a wireless network, the source device comprising: In response to a first command sent from the sink device receiving A / V data from a predetermined source device, the source device including indication information indicating whether or not the A / V data can be transmitted; An AVC layer for generating two commands; A MAC layer for constructing a MAC message including a message preamble, a message type, and the second command and delivering the MAC message to a physical layer; And A physical layer for generating a physical layer data unit including at least one header, the MAC message, and audio / video (A / V) data and transmitting the same to the sink device through the predetermined source device; And determine whether to switch to the source device to which the first command is transmitted according to the indication information included in the second command in the sink device.

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