HK1160317A - Wireless transmission system and wireless transmission method - Google Patents

Description

Wireless transmission system and wireless transmission method

Technical Field

The present invention relates to a wireless transmission system and a wireless transmission method, and more particularly, to a wireless transmission system and a wireless transmission method for wirelessly relaying CEC (consumer electronics control) communication of the HDMI (high definition multimedia interface) standard.

Background

A digital interface of the HDMI standard is widely used as a digital interface for transmitting video/audio and the like. The HDMI standard is arranged for AV (audio visual) devices by adding an audio transmission function and a copyright protection function to the DVI (digital visual interface) standard, which is a digital connection standard between a computer main body and a display. In the case of the HDMI standard, image (video) data/audio data is transmitted in a mode called TMDS (transition minimized differential signaling).

After version 1.2a, the CEC rule is added to the HDMI standard (see "Consumer Electronics Control (CEC) supplement 1" of non-patent document 1). The CEC protocol is a control protocol that performs control between devices connected through an HDMI cable. The CEC protocol implements various controls based on unique physical and logical addresses assigned to devices present on the HDMI network. For example, when watching digital broadcasting on a television apparatus, if a user starts reproduction by a DVD (digital versatile disc) player connected to HDMI, the television apparatus itself automatically switches an input to a terminal connected to the DVD player. The operation of the menu displayed by the DVD player, power on/off, and the like may be performed by a remote controller of the television apparatus.

Terms related to CEC are defined in non-patent document 1; those devices having HDMI inputs are defined as sink devices; and those having an HDMI output for outputting an AV stream are defined as source devices. A device defined as a repeater device has an HDMI input and an output for inputting/outputting an AV stream, and functions as both a sink device and a source device. The sink device mainly includes a display device; the source device includes an STB (set top box), various players for DVD, BD (blu-ray disc), and the like, and various recorders for DVD, BD, and the like; and a repeater including an AV amplifier, and the like.

Recently, wireless transmission of video/audio and CEC messages between a display device and a source device has been attempted. However, when the CEC message is transmitted by wireless, a problem is how to transmit ACK (acknowledgement) bits (ACK bits when CEC is supplied).

In this regard, patent document 1 proposes a radio transmission method in which a radio transmission apparatus transmits an ACK bit to realize radio transmission. In the wireless transmission method, when a first wireless transmission apparatus transmits a CEC message to a second wireless transmission apparatus, the first wireless transmission apparatus samples a wire interface at predetermined intervals, wirelessly transmits the sampled data to the second wireless transmission apparatus, holds a "0" output in the wire interface when the wire interface detects the start of an ACK bit of a header block or a data block, and holds a "0" output in the wire interface for a specified period of time when a wireless ACK packet indicating successful reception is received from the second wireless transmission apparatus.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No.2007 and 214952

Non-patent document

Non-patent document 1: high definition multimedia interface specification, version 1.3a, 2006, 11/10

Disclosure of Invention

Problems to be solved by the invention

However, only transmission of the ACK bit is performed in the wireless transmission method described in patent document 1, and thus the CEC protocol may fail under the influence of transmission delay, buffering delay, and the like of wireless communication. If a wireless channel without sufficient frequency band is used, useless transmission may occur.

These problems will be described more specifically. First, CEC is a communication protocol based on the assumption that metal lines are physically connected in an HDMI network. In communication using CEC, pulses are generated by lowering a common metal line that is pulled up to high (3.3V) and the opposite action, and therefore, if there is a section that does not share a metal line as in the case of a wireless transmission section, a delay always occurs and a correction pulse cannot be generated. Therefore, in the wireless transmission technology of HDMI, it is impossible to realize communication of CEC complying with the protocol.

Even if the wireless transmission method described in patent document 1 is applied, in part because all CEC messages must be exchanged between all devices, a response within a specified response time cannot be expected due to transmission delay (including response time delay) of wireless communication, and the CEC protocol may fail. Particularly in a system that transmits non-compressed video in HD (high definition) resolution, since it is necessary to allocate the maximum possible range of transmission frequency band to video/audio, a sufficient frequency band cannot be secured for other communications including CEC communication and a response within a specified response time cannot be expected. If a sufficient frequency band cannot be secured as described above, wireless transmission of the CEC message is wasted. If the buffering is simply used, the arrangement of the buffering itself causes a large delay because CEC communication is extremely slow communication, and therefore a response satisfying the response time cannot be made in a protocol (such as CEC) specifying the response time.

Even if the wireless transmission system described in patent document 1 is applied, the system may collapse when the wireless channel becomes too unstable to perform communication. More specifically, if such a situation occurs, if the ACK bit is returned to the CEC-message transmitting side, even if the CEC-message receiving side does not receive the CEC message, the CEC-message transmitting side judges that the transmission of the CEC message has been completed, which causes inconsistency and system crash.

The present invention has been conceived in view of these circumstances, and therefore it is an object of the present invention to provide a wireless transmission system and a wireless transmission method capable of preventing a CEC protocol from failing under the influence of a transmission delay, a buffering delay, and the like of wireless communication when CEC communication of the HDMI standard is wirelessly performed.

Means for solving the problems

In order to solve the above problem, a first technical means of the present invention is a wireless transmission system including: a first wireless communication device having a CEC control portion capable of transmitting/receiving CEC messages to/from the display device in HDMI, and a second wireless communication device having a CEC control portion capable of transmitting/receiving CEC messages to/from the AV device in HDMI, the wireless transmission system performs transmission/reception of a CEC message between the display apparatus and the AV apparatus through wireless communication between the first wireless communication apparatus and the second wireless communication apparatus, wherein the CEC control section of the first wireless communication device transmits/receives CEC messages to/from the CEC control section provided in the display device using a logical address corresponding to the device type of the AV device, and the CEC control section of the second wireless communication device transmits/receives CEC messages to/from the CEC control section provided in the AV device using a logical address corresponding to the device type of the display device.

A second technical means is the wireless transmission system of the first technical means, wherein the first wireless communication device determines whether transmission to the AV device is necessary or not depending on a type of the CEC message received from the display device and performs wireless transmission to the second wireless communication device only for the CEC message determined to have transmission need, and wherein the second wireless communication device determines whether transmission to the display device is necessary or not depending on the type of the CEC message received from the AV device and performs wireless transmission to the first wireless communication device only for the CEC message determined to have transmission need.

A third technical means is the wireless transmission system of the first or second technical means, wherein the first wireless communication device determines whether the CEC message received from the display device needs to have a response time period to the display device shorter than a predetermined time and makes a response to the CEC message that needs to have a shorter response time period, as a substitute for the AV device to respond to the display device, and wherein the second wireless communication device determines whether the CEC message received from the AV device needs to have a response time period to the AV device shorter than a predetermined time and makes a response to the CEC message that needs to have a shorter response time period, as a substitute for the display device to respond to the AV device.

A fourth technical means is the wireless transmission system of any one of the first to third technical means, wherein the CEC control portion of the first wireless communication device does not return the ACK bit to the display device even when receiving the CEC message from the display device when in a condition in which the first wireless communication device is unable to perform wireless communication with the second wireless communication device, and wherein the CEC control portion of the second wireless communication device does not return the ACK bit even when receiving the CEC message from the AV device when in a condition in which the second wireless communication device is unable to perform wireless communication with the first wireless communication device.

A fifth technical means is the wireless transmission system of any one of the first to fourth technical means, wherein the CEC control portion of the first wireless communication device is externally connected to a CEC control portion provided in the display device or is embedded in the display device and is connected to a CEC control portion provided in the display device, and wherein the CEC control portion of the second wireless communication device is externally connected to a CEC control portion provided in the AV device or is embedded in the AV device and is connected to a CEC control portion provided in the AV device.

A sixth technical means is a wireless transmission method of performing transmission/reception of a CEC message between a display device and an AV device through wireless communication between a first wireless communication device having a CEC control portion capable of transmitting/receiving a CEC message to/from the display device with HDMI and a second wireless communication device having a CEC control portion capable of transmitting/receiving a CEC message to/from the AV device with HDMI, using the first wireless communication device and the second wireless communication device, the method comprising the steps of: the CEC message is transmitted/received to/from the CEC control section provided in the display device by the CEC control section of the first wireless communication device using the logical address corresponding to the device type of the AV device, and the CEC message is transmitted/received to/from the CEC control section provided in the AV device by the CEC control section of the second wireless communication device using the logical address corresponding to the device type of the display device.

Effects of the invention

According to the present invention, when CEC communication of the HDMI standard is wirelessly performed, it is possible to prevent the CEC protocol from failing under the influence of transmission delay, buffering delay, and the like of wireless communication.

Brief Description of Drawings

Fig. 1 is a block diagram of an exemplary configuration of a wireless transmission system according to the present invention.

Fig. 2 is a diagram for explaining transmission/reception of CEC messages between devices in the wireless transmission system of fig. 1.

Fig. 3 is a flowchart for explaining an example of a process of a pretense operation from the time of power-on in the wireless transmission system of fig. 1.

Fig. 4 is a flowchart for explaining an example of a process when the remote controller is operated after the process at the time of power-on in the wireless transmission system of fig. 1.

Fig. 5 is a flowchart for explaining a case of delaying a response when a specific CEC message is transmitted/received after a process at power-on in the wireless transmission system of fig. 1.

Fig. 6 is a flowchart for explaining an example of a procedure when a CEC message is transmitted from a STB after the procedure when power is on in the wireless transmission system of fig. 1.

Fig. 7 is a flowchart for explaining an example of a procedure when a CEC message is transmitted from a STB after the procedure when power is on in the wireless transmission system of fig. 1.

Fig. 8 is a flowchart for explaining an example of a procedure when a CEC message is transmitted from a STB after the procedure when power is turned on in the wireless transmission system of fig. 1.

Fig. 9 is a flowchart for explaining an example of a procedure when a CEC message is transmitted from a STB after the procedure when power is turned on in the wireless transmission system of fig. 1.

Fig. 10 is a flowchart for explaining an example of a procedure when a CEC message is transmitted from a STB after the procedure when power is turned on in the wireless transmission system of fig. 1.

Fig. 11 is a flowchart for explaining an example of a procedure when a CEC message is transmitted from a STB after the procedure when power is turned on in the wireless transmission system of fig. 1.

Fig. 12 is a schematic diagram for explaining a case where a CEC message between devices cannot be communicated through a wireless transmission channel in the wireless transmission system of fig. 1.

Embodiments of the invention

A wireless transmission system according to the present invention (hereinafter referred to as the system) includes: the display apparatus includes a first wireless communication apparatus having a CEC control portion capable of transmitting/receiving CEC messages to/from the display apparatus, and a second wireless communication apparatus having a CEC control portion capable of transmitting/receiving CEC messages to/from the AV apparatus.

This system is a system that transmits a CEC message between the display apparatus and the AV apparatus through wireless communication between the first wireless communication apparatus and the second wireless communication apparatus (i.e., by relaying through wireless communication between the wireless communication apparatuses), and the method described in patent document 1 is available as a method of transmitting a CEC message including an ACK bit through wireless.

However, the method described in patent document 1 is mainly characterized in that the first wireless communication device and the second wireless communication device are each disguised as another device (a CEC-compatible device and another wireless communication device on the other side across the wireless transmission channel) because there is a possibility that the delay may fail as described above. The masquerading can establish two CEC networks divided into sections by a wireless transmission channel, and delay causing breakdown hardly occurs in this CEC network.

Although the present invention will now be described with reference to a system employing a monitor as a display device, the display device may be a television apparatus having a tuner. Although description will be made with reference to a system employing an STB as an AV device (AV device other than a display device), the AV device is not limited to the STB, and may be various recorders and players such as BDs, DVDs, and the like, simple tuner devices, Personal Computers (PCs), and game devices. The AV device is not limited to the source device, and may be a repeater device (such as an AV amplifier, and an STB and recorder having an HDMI input). However, as described below in an exemplary configuration, these display and AV devices are assumed to be CEC-compatible devices.

< exemplary configuration of Wireless Transmission System according to the present invention >

Fig. 1 is a block diagram of an exemplary configuration of a wireless transmission system according to the present invention. In fig. 1, 1 designates an STB as one example of an AV device; label the transmitter as one example of a second wireless communication device; 3 designating the receiver as an example of a first wireless communication device; and 4 designates a monitor as one example of the display device.

(apparatus on the conveying side)

The STB1 includes a wired (wired) connection section 11, a control section 12, and a storage section 13 for supporting CEC, and also includes other components for implementing functions such as an STB, such as a main control section 14 and a tuner section 15. The main control section 14 controls the entire STB1, including the control section 12. The tuner section 15 has: a tuner that receives a broadcast, a demodulation section that demodulates a broadcast, a demodulator that decodes demodulated video/audio data, and the like.

The wired connection portion 11 is an HDMI interface (I/F) for connecting an HDMI cable. Thus, the wired connection portion 11 is connected to the following lines included in the HDMI cable. The HDMI cable includes a CEC line that is a bidirectional bus that transmits a control signal (CEC message) common to the devices. In the CEC protocol, the transmission side can transmit a CEC message to a desired device by designating a logical address determined depending on a device type as a destination (transmission destination). If a logical address of the reception side (the logical address may be included as a broadcast transmission or the like) is described as a destination in the CEC message, the reception side receives the CEC message, and the transmission side can be identified from the logical address of the transmission source described in this CEC message.

In addition to the CEC line, the HDMI cable includes: a TMDS cable for transmitting a stream of video/audio signals as digital signals in a differential mode, a DDC (display data channel) line for transmitting EDID (extended display identification data), and the like. The EDID includes information on the type of signal that the display device can process, information such as the resolution of the display panel, and information such as the pixel clock, the horizontal effective period, and the vertical effective period. EDID is acquired by the video transmission side (STB 1 in this example) from the video display side (monitor 4 in this example) to transmit a video signal (display panel in monitor 4 in this example) adapted to the resolution of the display panel to be used.

The control section 12 is connected to the CEC line in the wired connection section 11. The control section 12 decodes the CEC message transmitted through the CEC line and received by the wired connection section 11, and returns an ACK bit or a response (status response or the like) to the CEC-message transmission source (the transmitter 2 in this example) through the CEC line as a response to the CEC message as necessary. The control part 12 delivers the decoded CEC message to the main control part 14 as needed, and the main control part 14 controls the entire STB1 to perform a process corresponding to the CEC message. For example, at the time of power-on or at the time of accepting an operation on the STB1, the control section 12 receives an instruction from the main control section 14, generates a CEC message corresponding to the instruction, and transmits the CEC message through the wired connection section 11.

The storage section 13 stores programs and information read from the control section 12 as needed. The control section 12 and the storage section 13 correspond to a CEC control section, and may be constituted by, for example, a microcomputer. The information includes a response table for specifying the operation. The programs include a CEC driver and a CEC manager.

The CEC driver is a program for transmitting and receiving CEC messages through the CEC line, and specifically performs control for reading the voltage of the CEC line in the wired connecting portion 11, short-circuiting the CEC line, and the like. Although described as a program, the CEC driver may be constituted of only hardware. The CEC management program is a program that instructs the CEC driver to return an ACK bit or a response to the main control section 14, or to transfer an instruction corresponding to a CEC message, by interpreting a CEC message received by the CEC driver and referring to a response table. The CEC management program also includes a program that receives an instruction from the main control section 14, generates a CEC message corresponding to the instruction that refers to the response table, and delivers the CEC message to the CEC driver via the wired connection section 11 for transmission.

An HDMI transmitter (not shown) is connected between the main control section 14 and the wired connection section 11. The HDMI transmitter transmits the packet stream of the video/audio signal received by the tuner section 15 from the wired connection section 11 to the wired connection section 21 of the transmitter 2 in the TMDS mode. In this case, the packet stream is transmitted through the TMDS channel of the TMDS line in the HDMI cable. The video signal transmitted by the HDMI transmitter is a signal having a resolution converted and adapted to the display panel of the monitor 4 as described above, and may be a video signal subjected to another video processing depending on the configuration of the STB 1. The audio signal transmitted through the HDMI transmitter may be an audio signal subjected to audio processing depending on the configuration of the STB 1.

The transmitter 2 includes a wired connecting section 21, a control section 22, and a storage section 23 for supporting CEC, and also includes a wireless connecting section (wireless communication section) 24 for realizing wireless communication. The wired connection portion 21 is an HDMI I/F for connecting an HDMI cable, and is connectable to the wired connection portion 11 of the STB1 via this HDMI cable. The STB1 and the transmitter 2 can transmit and receive CEC messages by the connection between the wired connection portion 11 and the wired connection portion 21 through the HDMI cable.

The control section 22 is connected to the CEC line of the HDMI cable via the wired connection section 21, and is also connected to the wireless connection section 24. The control section 22 decodes a CEC message transmitted through the CEC line and received by the wired connection section 21, and returns an ACK bit or a response to the CEC message transmission source (STB 1 in this example) through the CEC line as a response to the CEC message, and transmits the decoded CEC message to the receiver 3 through the wireless connection section 24 by wireless as needed. The control section 22 decodes the wireless transmission information (information indicating CEC information) received by the wireless connection section 24, and transmits (transfers) the decoded CEC message to the STB1 through the CEC line in the wired connection section 21.

In such transmission/reception of the CEC message, transmission/reception between the STB1 and the transmitter 2 is performed with the transmitter 2 pretending to be the monitor 4. The configuration for this disguise is the main feature of the present invention and will be described.

The storage section 23 stores programs and information read from the control section 22 as needed. The control section 22 and the storage section 23 may be constituted by a microcomputer, for example. The information stored in the storage section 23 includes a response table 23c for specifying an operation. The response table 23c is used for masquerading.

In the response table 23c of the transmitter 2, an operation for working as a CEC compliant device to be disguised (in this case, "TV" corresponding to the monitor 4) is preset in advance. The operation is defined as: the CEC message is transmitted/received to/from the CEC control section of the AV device (STB 1 in this case) by using the logical address (0) corresponding to the device Type (TV) of the monitor 4 and the receiver 3 on the other side across the wireless transmission channel. If a response to the STB1 is required, a response may be returned to the STB1, essentially after waiting for information from the monitor 4 (actually the receiver 3) indicating a CEC message of the response. The CEC control section of the transmitter 2 mainly corresponds to the control section 22, CEC driver 23a, and CEC manager 23b, while the CEC control section of the STB1 mainly corresponds to the control section 12 and storage section 13.

By using the logical address "0" in the transmitter 2, it is possible to transmit/receive CEC messages to/from the STB1 as defined in the CEC protocol (including vendor commands). The vendor command identifies the command specified by the vendor specific command, such as < vendor command > and < vendor command with ID > that allow the vendor (manufacturer) to uniquely specify the operation. The specification can be described with vendor-specific data in these commands (messages) when the operation is uniquely specified.

Although the transmitter 2 transmits information indicating a CEC message (i.e., a wireless message corresponding to CEC information) to the receiver 3, the transmitter 2 transmits only information indicating a CEC message received from the STB1 (a CEC message including a logical address of the STB1 as a transmission source) by wireless, without performing transmission to the receiver 3 by using the logical address (0) used by the transmitter 2 itself as a transmission source.

The programs stored in the storage section 23 include a CEC driver 23a, a CEC manager 23b, a wireless communication driver 23d, and the like. The CEC driver 23a is the same as that of the STB1, and is a driver for transmitting/receiving CEC messages over the CEC line. The CEC management program 23b interprets the CEC message received by the CEC driver 23a from the STB1 and refers to the response table 23c to instruct the CEC driver 23a to return an ACK bit or a response, or refers to the response table 23c to deliver information indicating the CEC message to the wireless communication driver 23d to drive the wireless connection section 24 to transmit information wirelessly. The wireless communication driver 23d is a driver that drives the wireless connection section 24 to wirelessly transmit information indicating a CEC message based on an instruction from the CEC management program 23b, and although it is described that the program may be constituted of only hardware.

The wireless communication driver 23d also performs processing for delivering information indicating a CEC message received by the wireless connection section 24 from the receiver 3 to the CEC management program 23 b. When receiving information indicating a CEC message from the wireless communication driver 23d, the CEC manager 23b interprets (extracts) the CEC message and refers to the response table 23c to instruct the CEC driver 23a to transmit CEC information to the STB 1.

An HDMI sink (not shown) is connected between the wireless connection section 24 and the wired connection section 21. This HDMI receiver receives a video/audio packet transmitted from the HDMI transmitter of the STB1 via the wired connection portion 11 through the TMDS line through the wired connection portion 21, and delivers the packet to the wireless connection portion 24. The video/audio packets received by the HDMI receiver of the transmitter 2 are configured to be transmitted by wireless via the wireless connection section 24. The video/audio packets can be transmitted wirelessly by allocating TMDS channels in the same manner as done in transmission through the TDMS line.

(apparatus on receiving side)

The monitor 4 includes a wired connection section 41, a control section 42, and a storage section 43 for supporting CEC, and also includes other components for realizing functions as a monitor, such as a main control section 44, a video processing section 45 such as a video processor, a display section 46 having a display panel such as an LCD, and a light receiving section 47. The main control section 44 controls the entire monitor 4, including the control section 42. The light receiving section 47 receives an operation signal from the remote controller 5 and delivers the operation signal to the main control section 44.

The wired connection portion 41 is an HDMI interface (I/F) for connecting an HDMI cable. The control section 42 is connected to the CEC line in the wired connection section 11. The control section 42 transmits the EDID to the receiver 3, and the EDID is transmitted to the STB1 via the transmitter 2 to enable the STB1 to transmit a video signal adapted to the display resolution of the display section 46. The control section 42 decodes the CEC message transmitted through the CEC line and received by the wired connection section 41, and returns an ACK bit or a response to the CEC-message transmission source (the receiver 3 in this example) through the CEC line as needed. The control section 42 delivers the decoded CEC message to the main control section 44 as needed, and the main control section 44 controls the entire monitor 4 to perform processing according to the CEC message. For example, upon power-on or upon receiving an operation signal of a user operation through the light receiving section 47, the control section 42 receives an instruction from the main control section 44, generates a CEC message depending on the instruction, and transmits the CEC message through the wired connection section 41.

The storage section 43 stores programs and information read from the control section 42 as needed. The control section 42 and the storage section 43 correspond to a CEC control section, and may be constituted by a microcomputer, for example. The information includes a response table for specifying the operation. The programs include a CEC driver and a CEC manager.

The CEC driver is a program for transmitting and receiving CEC messages through the CEC line, and specifically, it reads the voltage of the CEC line in the wired connecting portion 41 and controls the applied voltage. Although described as a program, the CEC driver may be constituted of only hardware. The CEC management program is a program that instructs the CEC driver to return an ACK bit or a response to the main control section 44, or to transfer an instruction corresponding to a CEC message, by interpreting a CEC message received by the CEC driver and referring to a response table. The CEC management program also includes a program that receives an instruction from the main control section 44, generates a CEC message corresponding to the instruction that refers to the response table, and delivers the CEC message to the CEC driver via the wired connection section 41 for transmission.

An HDMI receiver (not shown) is connected between the video processing section 45 and the wired connection section 41. The HDMI receiver receives a stream of video/audio signals (signals originally acquired by the tuner section 15 of the STB 1) from the receiver 3 via the wired connection section 41, demultiplexes the stream into video/audio signals, and outputs the video signals (video signals adapted to the resolution of the display section 46) to the video processing section 45. The video processing section 45 gives various types of video processing to the video signal based on an instruction from the main control section, and shows the video signal to the display section 46, and the display section 46 displays the video. The HDMI receiver outputs the demultiplexed audio signal to an audio processing section (not shown); the audio processing section performs various types of audio processing based on instructions from the main control section 44 and outputs an audio signal to a speaker (not shown), and the speaker outputs a sound.

The receiver 3 includes a wired connecting section 31, a control section 32, and a storage section 33 for supporting CEC, and further includes a wireless connecting section (wireless communication section) 34 for realizing wireless communication. The wired connection portion 31 is an HDMI I/F for connecting an HDMI cable, and it can be connected to the wired connection portion 41 of the monitor 4 via this HDMI cable. By the connection between the wired connection portion 31 and the wired connection portion 41 through the HDMI cable, the receiver 3 and the monitor 4 can transmit and receive CEC messages.

The control section 32 is connected to the CEC line of the HDMI cable via the wired connection section 31, and is also connected to the wireless connection section 34. The control section 32 decodes a CEC message transmitted through the CEC line and received by the wired connection section 31, and returns an ACK bit or a response to the CEC message transmission source (the monitor 4 in this example) through the CEC line as a response to the CEC message as needed, and transmits the decoded CEC message to the transmitter 2 through the wireless connection section 24 by wireless as needed. The control section 32 decodes the wireless transmission information (information indicating a CEC message) received by the wireless connection section 34, and transmits the decoded CEC message to the monitor 4 through the CEC line in the wired connection section 31.

In such transmission/reception of the CEC message, transmission/reception between the monitor 4 and the receiver 3 is performed with the receiver 3 pretended to be the STB 1. The configuration for this disguise is the main feature of the present invention and will be described.

The storage section 33 stores programs and information read from the control section 32 as needed. The control section 32 and the storage section 33 may be constituted by a microcomputer, for example. The information stored in the storage section 33 includes a response table 33c for specifying an operation. For masquerading, masquerading with this response table 33c is performed on the receiving side in addition to masquerading on the transmitting side (response table 23c of transmitter 2).

In the response table 33c of the receiver 3, an operation for working as a CEC-compatible device to be disguised (in this case, a "tuner" corresponding to the STB 1) is preset in advance. The operation is defined as: the receiver 3 transmits/receives a CEC message to/from the CEC control section of the display device (monitor 4 in this example) by using a logical address (any of 3, 6, 7 and 10) corresponding to the device type (tuner) of the STB1 and the transmitter 2 on the other side across the wireless transmission channel. If a response to the monitor 4 is required, the response may be returned to the monitor 4, substantially after waiting for information from the STB1 (actually the transmitter 2) indicating the CEC message of the response. The CEC control section of the receiver 3 mainly corresponds to the control section 32, CEC driver 33a, CEC manager 33b, and response table 33c, while the CEC control section of the monitor 4 mainly corresponds to the control section 42 and storage section 43.

By using any of the logical addresses "3, 6, 7 and 10" in the receiver 3, it is possible to transmit/receive CEC messages to/from the monitor 4 as defined in the CEC protocol (including vendor commands). Although the receiver 3 transmits information indicating a CEC message (i.e., a wireless message corresponding to CEC information) to the transmitter 2, the receiver 3 performs transmission to the transmitter 2 only by wirelessly transmitting information indicating a CEC message received from the monitor 4 (a CEC message including the logical address "0" of the monitor 4 as a transmission source), without using the logical address (any one of 3, 6, 7, and 10) used by the receiver 3 itself as a transmission source.

The programs stored in the storage section 33 include a CEC driver 33a, a CEC management program 33b, a wireless communication driver 33d, and the like, which are the same as the CEC driver 23 a. The CEC management program 33b interprets the CEC message received by the CEC driver 33a from the monitor 4 and refers to the response table 33c to instruct the CEC driver 33a to return an ACK bit or a response, or refers to the response table 33c to deliver information indicating the CEC message to the wireless communication driver 33d to drive the wireless connection section 34 to transmit the information wirelessly. The wireless communication driver 33d is a driver that drives the wireless connection section 34 to wirelessly transmit information indicating a CEC message based on an instruction from the CEC management program 33b, and although it is described that the program may be constituted of only hardware.

The wireless communication driver 33d also performs processing for delivering information indicating a CEC message received by the wireless connection section 34 from the transmitter 2 to the CEC management program 33 b. When receiving the information indicating the CEC message from the wireless management driver 33d, the CEC manager 33b interprets (extracts) the CEC message and refers to the response table 33c to instruct the CEC driver 33a to transmit the CEC message to the monitor 4.

In the case of the receiver 3, unlike the transmitter 2, the operations to be set in advance differ depending on whether it is necessary to implement a CEC connection by wireless by the STB1 as exemplarily shown in fig. 1 or a CEC connection by wireless by the recorder or player. Therefore, the response table 33c may preliminarily store operations corresponding to each of all or a plurality of devices as AV devices except the display device, so that the user can select a device (a device to be communicated) with, for example, a switch button provided on the receiver 3. Only operations corresponding to the devices selected by the user may be set to be enabled in the response table 33 c.

In the CEC protocol, 3, 6, 7, and 10 are arranged as logical addresses corresponding to the tuners, and the receiver 3 can set any of these addresses as described above. If there is a tuner device other than the STB1 in the lower layer of the STB1 of the cable CEC network on the transmission side, the logical address of the STB1 may be "6" in some cases. Although it can be specified that: as long as the first declaration tuner 1 (logical address 3) is absent in the wired CEC network on the receiver side, it is detected from the CEC message (vendor command) that a tuner device other than STB1 on the receiver side has this tuner 1 and is preset as tuner 2 (logical address 6), but even if an operation of presetting logical address 3 (a value different from the logical address of STB 1) to receiver 3, when the transmitter 2 interprets a wireless message of the CEC message indicating logical address 3 and transmits the message through the CEC line, the transmission can be performed with the logical address rewritten from 3 to 6 (because it is known that STB1 corresponds to "6") without problems.

An HDMI transmitter (not shown) is connected between the wireless connection section 34 and the wired connection section 31. The HDMI transmitter converts the video/audio packets received by the wireless connection portion 34 into a TDMS format, and transmits the video/audio packets to the monitor 4 (HDMI receiver of the monitor 4) via the wired connection portion 31 and TDMS line for each TDMS channel.

(outline of exemplary configuration)

As described above, the wireless transmission system of fig. 1 introduces the following mechanism: in wireless transmission between the STB1 and the monitor 4, the transmitter (Tx)2 performs communication as the monitor 4, and the receiver (Rx)3 performs communication as the STB 1.

More specifically, for the masquerading device in the response table 23c (/ response table 33c), an operation for working as a masquerading device is set in advance; the transmitter 2(/ receiver 3) acquires a logical address of the monitor 4(/ STB 1) located on the other side, and receives a CEC message from the STB 1(/ monitor 4) to transmit the received CEC message to the monitor 4(/ STB 1) side; and CEC messages received from the monitor 4(/ STB 1) side can also be transmitted to the STB 1(/ monitor 4). The CEC management program 23b (/33b) receives data each received by the CEC driver 23a (/33a) and the wireless communication driver 23d (/33d) to perform control of determining "a CEC message to be transmitted as a wireless message to the other side (CEC-message transmission destination) of the CEC message to be replied to" from the response table 23c (/33c) (and communication history information stored in the communication memory 23e/33e as in an example described later) and delivering it to the wireless communication driver 23d, and perform control of determining an ACK bit of the CEC message or a response to the CEC-message transmission source from the response table 23 CEC (/33c) (and communication history information) and delivering it to the CEC driver 23 a.

A description will be made with reference to fig. 2. Fig. 2 is a diagram for explaining transmission/reception of CEC messages between devices in the wireless transmission system of fig. 1. From STB1, transmitter 2 is considered as monitor 4 with logical address 0; from the monitor 4, the receiver 3 is seen as a STB1 with any one of the logical addresses 3, 6, 7 and 10 ("3" in this example); and CEC messages (CEC commands) received from the STB1 and the monitor 4 may be interchanged between the transmitter 2 and the receiver 3. Accordingly, the transmitter 2 returns an ACK bit from the STB1 to the logical address of the TV in response to the CEC message and transmits the CEC message to the receiver 3, and the receiver 3 serves as a tuner to transmit the CEC message to the monitor 4. Instead, the receiver 3 returns an ACK bit from the TV to the logical address of the STB in response to the message and transmits the message to the transmitter 2, and the transmitter 2 transmits the message to the STB1 as the TV.

This configuration enables CEC communication through a wireless transmission channel in both the monitor 4 and the STB1, which has conventionally been regarded as impossible without changing the protocol because of delay or the like. In particular, the transmitter 2 and the receiver 3 may ignore CEC messages to a disguised device (pretended device) because of disguising (emulation), and thus it is no longer necessary to perform wireless transmission for all CEC messages to the other side, and at least more delay is eliminated in this respect because transmissions from multiple devices may be congested. This masquerading also allows implementation of "a procedure corresponding to the type of CEC message" described later and "processing in which a response is returned by the transmitter 2 or the receiver 3 as an alternative depending on the time limit for responding to a CEC message".

< example of transmission/reception of CEC message in exemplary configuration >

Fig. 3 is a flowchart for explaining an example of a procedure of the masquerading operation from the time of power-on in the wireless transmission system of fig. 1. In fig. 3 and fig. 4-11 described later, arrows are shown to represent transmissions between devices; the solid arrow indicates that an ACK bit is returned; and the dashed arrow indicates that no ACK bit is returned; for example, step S4 of fig. 3 indicates that no ACK bit is returned, while step S13 indicates that there is a return of an ACK bit from STB1 to transmitter 2. However, although the ACK bit is not transmitted in the communication between the transmitter 2 and the receiver 3, since the communication conforms to a protocol dedicated to wireless communication and is different from CEC, it is assumed that the communication is ensured in some way. The illustrated rule does not apply to arrows other than transmission, such as steps S1, S2, and S15, and step S24 of fig. 4.

The transmitter 2 has a response table 23c preset to operate as the monitor 4 (step S1), and the receiver 3 has a response table 33c preset to operate as the STB1 (step S2).

In this state, when a CEC connection is realized between the STB1 and the transmitter 2 through the HDMI cable and a CEC connection is realized between the receiver 3 and the monitor 4 through the HDMI cable, upon power-on (power-up) of the respective devices (step S3), the STB1 checks whether another STB (device corresponding to the tuner) is present in order to declare itself as an STB (assumed to have the logical address 3) (step S4). The receiver 3 checks whether another STB (a device corresponding to the tuner) is present in order to declare itself an STB (assumed to have logical address 3) (step S6). Therefore, in steps S4 and S6, it is confirmed that no ACK bit is returned through CEC communication destined to the STB. This communication may be performed by, for example, < Polling message >.

In the same manner, the transmitter 2 checks whether there is another TV in order to declare itself as a TV (logical address 0) (step S5), and the monitor 4 checks whether there is another TV in order to declare itself as a TV (logical address 0) (step S7). Therefore, in steps S5 and S7, it is confirmed that no ACK bit is returned through CEC communication destined for the TV. This confirmation processing (any of steps S4 to S7) may be performed from when the device is powered on and connected to the HDMI cable, regardless of the order of the powering on of step S3 and the fact that which of the powering on and the connection to the HDMI cable was performed first. Although each of the devices 1 to 4 can determine a logical address through the processes of steps S4 to S7 in the exemplary configuration of fig. 1, if an ACK bit is returned because another device is connected, it may be attempted to set another logical address of the same device type in the same manner.

Although not shown in fig. 3, an arrangement is made to transmit < device vendor ID > after steps S4 to S7, which is a message for broadcast transmission of vendor IDs (unique vendor IDs defined by the IEEE organization) stored in the respective devices. At least the monitor 4 completes this transfer before transmitting the vendor command as described below. Between the devices 1 to 3, before transmitting a vendor command as described below, notification of a vendor ID can be made by a device whose vendor ID is not received by the < give device vendor ID > drive monitor 4. The vendor command described below can be received substantially when the vendor IDs are the same (or when a process in which the vendor IDs can be regarded as the same is performed).

Once the logical addresses have been determined in the devices 1 to 4 as described above, the transmitter 2 and the receiver 3 start the disguise operation according to the invention. Thus, once the logical address is determined, the transmitter 2 starts operating as the monitor 4 on the CEC line to which the transmitter 2 is connected, and the receiver 3 starts operating as the STB1 on the CEC line to which the receiver 3 is connected. Since some kind of mechanism for confirming the presence must be introduced to the mutually cooperative devices, in the example shown in fig. 3, it is assumed that the monitor 4 and the STB1 perform a search by transmitting a vendor (ping) (vendor (ping)) defined as a vendor command at predetermined intervals until returning a vendor (acknowledgement) (vendor (ack)) as a response to the vendor (ping) confirms the mutual presence regardless of the presence or absence of a wireless section. In this step, the intercommunication can be divided into a plurality of steps in a more complex manner. First, even if there is a wireless section, the monitor 4 performs a search by transmitting a provider (ping) defined as a provider command at predetermined intervals until the provider (confirmation) is returned as a response to the provider (ping) (step S11). This search process can be described as a process for starting an operation in the response table in the storage section 43 of the monitor 4.

In step S11, a vendor (ping) is first transmitted through the CEC line (step S11 a). When receiving the provider (ping) at step S11a, the receiver 3 refers to the response table 33c to return the ACK bit as the STB1 and transmits information indicating the provider (ping), i.e., a wireless message indicating the provider (ping) by wireless (step S12). In step S12, a process of storing the logical address to which the provider (ping) is transmitted (the logical address of the transmission source included in the provider (ping), in this example, "0" of the monitor 4) in the communication memory 33e is also performed. The device having the logical address stored at this step is judged as the corresponding device, i.e., the opposite party of the pairing operation, when pretended (emulated) as STB 1. It is assumed that the response table 33c of the receiver 3 includes specifications for this operation, i.e., specifications for returning an ACK bit to the provider (ping), storing a logical address, and performing wireless transmission of information indicating the provider (ping).

Upon receiving the wireless message, the transmitter 2 extracts the provider (ping) from the wireless message and transmits the provider (ping) through the CEC line (step S13). It is assumed that the response table 23c of the transmitter 2 includes specifications for such an operation. Upon receiving the provider (ping), the STB1 refers to the response table in the storage section 13 to return an ACK bit, and transmits the provider (acknowledgement) as a response to the provider (ping) through the CEC line (step S14). It is assumed that the response table in the storage section 13 of the STB1 includes a specification for such an operation, i.e., a specification for returning an ACK bit to the provider (ping) and returning a provider (acknowledgement) to the provider (ping) as a response (using the transmission source in the provider (ping) as a destination).

Upon receiving the provider (acknowledgement), the transmitter 2 refers to the response table 23c to return the ACK bit, and stores in the communication memory 23e the logical address of the return provider (acknowledgement) (the logical address of the transmission source included in the provider (acknowledgement), "3" of the STB1 in this example). The device having the logical address stored at this step is judged as the target device, i.e., the counterpart of the pairing operation, when pretending (emulating) to be the monitor 4. The transmitter 2 wirelessly transmits information indicating the provider (confirmation), i.e., a wireless message indicating the provider (confirmation) (step S16). It is assumed that the response table 23c of the transmitter 2 includes specifications for returning an ACK bit to the provider (acknowledgment), storing a logical address of a transmission source in the communication memory 23e, starting a pairing operation of accepting the logical address, and transmitting a wireless message indicating the provider (acknowledgment) by wireless.

Upon receiving the wireless message, the receiver 3 extracts the provider (confirmation) from this wireless message, and transmits the provider (confirmation) through the CEC line (step S17). It is assumed that the response table 23c of the receiver 3 includes specifications for such an operation.

Upon receiving the provider (acknowledgement), the monitor 4 refers to the response table in the storage section 43 to return the ACK bit, and stores the logical address of the return provider (acknowledgement) (the logical address of the transmission source included in the provider (acknowledgement), in this case, "3" of the STB 1) in the communication memory of the storage section 43, and starts accepting the pairing operation for the STB1 at this timing (step S18). Therefore, the device having the logical address stored at this step is determined as the opposite party of the pairing operation. It is assumed that the response table in the storage section 43 of the monitor 4 includes a specification for such an operation as returning an ACK bit to a vendor (acknowledge), storing a logical address of a transmission source in the communication memory, and starting a pairing operation of accepting the logical address.

As described above, by using authentication communication such as vendor (ping) between devices operating in cooperation with each other, a device to be disguised in the present invention can be searched. If there is no such mechanism between the devices, this can be achieved by performing a preset operation using the fixed logical addresses of the devices operating in cooperation with each other. Although it has been described that the notification of the vendor ID must be given in advance before the vendor (ping) is issued, if the vendor (ping) is issued by using < vendor command with ID > instead of < vendor command >, the notification of the vendor ID does not have to be given in advance. In this case, it is recommended to transmit < device vendor ID >, and then perform communication through < vendor command > after issuing a vendor (ping) to check the vendor (confirmation).

Fig. 4 is a flowchart for explaining an example of a process when the remote controller is operated after the process at the time of power-on in the wireless transmission system of fig. 1. It is described how the light receiving section 47 operates when the light receiving section 47 receives an operation signal corresponding to a Vendor Remote controller Down (Vendor Remote Down) from the Remote controller 5. Such operations may be stored in a response table of the device, as described with reference to FIG. 3.

First, the monitor 4 interprets the operation signal and refers to the response table to transmit a CEC command called vendor remote controller down through the CEC line (step S21). Upon receiving this downward movement of the provider remote controller, the receiver 3 refers to the response table 33c to return the ACK bit as the STB1, and transmits information (wireless message) indicating that the provider remote controller is downward by wireless (step S22). Upon receiving the wireless message, the transmitter 2 extracts the vendor remote controller down, and refers to the response table 23c to transmit the vendor remote controller down (by using the logical address of the monitor 4 as the transmission source) as the monitor 4 through the CEC line to the destination, which is the logical address stored in the communication memory 23e (the logical address stored at step S15) (step S23). Upon receiving the downward direction of the provider remote controller, the STB1 refers to the response table to return the ACK bit and performs a process (e.g., a process such as changing a channel) corresponding to the downward direction of the provider remote controller (step S24). The STB1 can be operated in this way from the remote control 5 of the monitor 4.

Fig. 5 is a flowchart for explaining a case of delaying a response when transmitting/receiving a specific CEC message after processing at power-on in the wireless transmission system of fig. 1. Although the masquerading of the transmitter 2 and the receiver 3 as described with reference to fig. 1 to 4 is extremely effective in preventing delay, all CEC messages transmitted to the masquerading device (not all CEC messages on the CEC line) must be transmitted only when this masquerading is used. In the description of fig. 1 and the like, the portion described as "on-demand-based" transmission means that the transmission is performed on an on-demand basis in conformity with the CEC protocol.

If all CEC messages to the disguised device are transmitted in this manner, the band on the link is consumed and some of the commands that need to be responded to within a certain period of time become unsupported (e.g., response < set flow path > to command < change of route >). In the present description, it is assumed that the command sequence taken as an example uses a command requiring 100ms from the start of transmission to the end of transmission and requires a response within 300 ms. As exemplarily shown in fig. 5, when the transmitter 2 performs reception while buffering and performs transmission to the receiver 3 after completion, it takes an additional 100ms after the transmitter 2 completes reception until the receiver 3 can complete transmission to the monitor 4 (although communication delay is generated in the wireless transmission section strictly speaking, communication delay is ignored for the sake of simplicity). It is assumed that the monitor 4 responds within 200ms, which is within the scope of the standard. When the receiver 3 completely receives the response and performs transmission to the transmitter 2 in the same manner, it takes an additional 100ms after the receiver 3 completes reception until the transmitter 2 completes transmission. Thus, although a response is made within 200ms (within the range of the standard) on the CEC line to which the receiver 3 is connected, it takes more than 400ms of the standard on the CEC line to which the transmitter 2 is connected.

As a countermeasure, it is necessary for some of the CEC messages to skip wireless transmission to the disguised device. Such a process will be described. If the delay described with reference to fig. 5 occurs (including a case where the delay is caused due to insufficient band), the following processing may be performed.

The CEC control section of the receiver 3 determines whether transmission to the STB1 (transmitter 2) is necessary depending on the type of CEC message (including the case of vendor command) received from the monitor 4, and transmits the CEC message to the transmitter 2 by wireless via the wireless connection section 34 only when it is determined that transmission is necessary. The CEC control section of the transmitter 2 also determines whether transmission to the monitor 4 (receiver 3) is necessary depending on the type of CEC message received from the STB1, and transmits the CEC message to the receiver 3 by wireless via the wireless connection section 24 only when it is determined that transmission is necessary. Such operations may be described in response tables 23c, 33c and performed by CEC managers 23b, 33 b.

More specifically, assuming that a device to be emulated is identified, because the response of the CEC may be returned as a fixed value or a value determined from the content of the previous communication, the transmitter 2/receiver 3 responds by itself without the transmitter 2/receiver 3 communicating with the other side to obtain the result. Therefore, the problem of response time can be solved, and the amount of communication between the transmitter 2 and the receiver 3 can be reduced. The amount of communication can be further reduced by transmitting only the parameters necessary for this response, and by receiving only and not transmitting commands that are unnecessary as a reaction when the TV or STB is operating.

Examples of such processing will be described with reference to fig. 6-11. Fig. 6 to 11 are flowcharts for explaining an example of a procedure when a CEC message is transmitted from an STB after processing at the time of power-on in the wireless transmission system of fig. 1.

As shown in fig. 6, the transmitter 2 receives the CEC message from the STB1 (step S31), and if the CEC message is determined to be a CEC message that does not require a response, the transmitter 2 returns only the ACK bit and ignores the CEC message.

As shown in fig. 7, the transmitter 2 receives the CEC message from the STB1 (step S41), and if it is determined that the response may be the preceding communication content (or a fixed value) on the assumption that the device to be disguised has been identified although the CEC message requires the response, the transmitter 2 returns an ACK bit and returns only a response (or a response having a preset value) determined from the history of communication with the monitor 4 in the communication memory 23 (step S42) without performing wireless communication. < power state given > may be cited as an example of a case where the preceding communication content can be used, and the response determined from the communication history in this case is < power state reported >. < given vendor ID > can be cited as an example of a case where a fixed value can be used, and the response with a preset value in this case is < device vendor ID >.

As shown in fig. 8, the transmitter 2 receives the CEC message from the STB1 (step S51), and if it is determined that the CEC message allows communication with the monitor 4 to be performed subsequently after the response is returned first, the transmitter 2 returns an ACK bit, performs wireless transmission of information indicating the message (step S52), and returns a response having a preset value to the STB1 through the CEC line (step S53). An example of such CEC information is < route change > (only when the STB1 is a repeater device, since this example is assumed based on transmission from the STB1 side), and a response having a preset value in this case is < setup flow path >. The order of step S52 and step S53 is not limited as long as the response of step S53 is made within the range of the standard. Upon receiving the wireless message of step S52, the receiver 3 transmits a CEC message indicated by the wireless message to the monitor 4 through the CEC line (step S54), and acquires a response thereto from the monitor 4 (step S55). This response is not necessary for the receiver 3 and is therefore negligible.

As shown in fig. 9, the transmitter 2 receives a CEC message from the STB1 (step S61), and if the CEC message is determined to be a CEC message that can be transmitted in a unique direction (e.g., < image view on >, i.e., a power-on instruction), the transmitter 2 returns an ACK bit and transmits information indicating the message by wireless (step S62). Upon receiving the information (wireless message), the receiver 3 extracts the message and transmits the message to the monitor 4 through the CEC line (step S63).

As shown in fig. 10, the transmitter 2 receives the CEC message from the STB1 (step S71), and if the CEC message requires a response that cannot be determined according to a preset value, communication contents, and the like, performs a normal procedure without skipping (steps S72 to S76). The transmitter 2 returns the ACK bit and performs wireless transmission of information indicating the message (step S72), and when receiving the information, the receiver 3 extracts the message and transmits the message to the monitor 4 through the CEC line (step S73). The monitor 4 transmits a response thereto to the receiver 3 through the CEC line (step S74); the receiver 3 wirelessly transmits information indicating a response (step S75); and, upon receiving the information, the transmitter 2 extracts the response and transmits the response to the STB1 through the CEC line (step S76). An example of such CEC information is < vendor command >, which depends on the arrangement in the vendor. The response thereto is predefined and stored in the response table of the monitor 4.

As shown in fig. 11, the transmitter 2 receives the CEC message from the STB1 (step S81), and if it is determined that the CEC message is communicated to a device other than the masquerading device (i.e., the monitor 4), the transmitter 2 does not return the ACK bit and does not perform wireless transmission.

Although the process example in the case of transmitting a CEC message from the STB1 has been described with reference to fig. 6 to 11, the process example in the case of transmitting a CEC message from the monitor 4 is described in the same manner in the opposite direction.

The transmitter 2 or the receiver 3 may control whether to perform wireless transmission and whether the transmitter 2 or the receiver 3 returns a response instead depending on a time limit (response time) of the response defined in the CEC protocol, i.e., a response time limit.

Accordingly, the receiver 3 determines whether the CEC message received from the monitor 4 needs to have a response time limit to the monitor 4 shorter than a predetermined time. As a result of the determination, for CEC messages that need to have a shorter response time limit, the receiver 3 responds instead of the STB1 (in a sense the transmitter 2) responding to the monitor 4. In this case, wireless transmission to the transmitter 2 may not be performed. The wireless transmission may be performed for other CEC messages. The CEC management program 33b may be enabled to make the determination by referring to the response table 33c, and the response may be a preset message defined in advance for each CEC message in the response table 33 c.

Also, the transmitter 2 determines whether the CEC message received from the STB1 needs to have a response time limit to the STB1 shorter than a predetermined time, and makes a response to the CEC message that needs to have a shorter response time limit instead of the response of the monitor 4 to the STB 1. In this case, wireless transmission to the receiver 3 may not be performed. The wireless transmission may be performed for other CEC messages. The CEC management program 23b may be enabled to make the determination by referring to the response table 23c, and the response may be a preset message defined in advance in the response table 23c for each CEC message.

Whether to perform wireless transmission or to return a response by itself depending on the response time limit of the received CEC message (i.e., the type of CEC message related to the response time limit) control of this form may be implemented independently of the examples described with reference to fig. 6 to 10, or may be applied to the examples described with reference to fig. 7 and 8. In the latter case, the examples described with reference to fig. 7 and 8 are applicable only to CEC messages that need to have a shorter response time limit. In the examples of fig. 9 and 10, a tentative response may be made by setting the appropriate response to a preset value without exceeding the standard range of response implementation. In the case where the CEC message does not require wireless transmission as in the example of fig. 6 in the case where wireless transmission is not required in this form of control whether wireless transmission is performed or a response is returned by itself, the CEC message may also be unconditionally ignored without returning a response and performing wireless transmission, and if the CEC message is destined for a device other than its own disguised device as in fig. 11, the CEC message may be ignored in the same format.

Fig. 12 is a diagram for explaining a case where a wireless transmission channel cannot communicate by transmission/reception of a CEC message between devices in the wireless transmission system of fig. 1. In the case of wireless communication, the communication may be interrupted due to radio wave conditions. If a message is received in this state, the devices cannot communicate messages therebetween. The reception of the message means that an ACK bit is returned and it is determined that the communication is successful on the transmitting side. As a result, the state that the transmitting side knows becomes different from the state that the receiving side knows, causing a breakdown.

Therefore, when in a situation where it is impossible to make wireless transmission, it is preferable not to return the ACK bit even when the CEC communication is received. When in a condition in which the receiver 3 cannot perform wireless communication with the transmitter 2, the CEC control section of the receiver 3 does not return the ACK bit to the monitor 4 even if the CEC message is received from the monitor 4, and when in a condition in which the transmitter 2 cannot perform wireless communication with the receiver 3, the CEC control section of the transmitter 2 does not return the ACK bit even if the CEC message is received from the STB 1. Such operations may be described in response tables 23c, 33c and performed by CEC managers 23b, 33 b. The availability/unavailability of wireless communication can be determined by storing a history of wireless communication (communication history for determining whether communication is interrupted or available) in advance in the communication memory 23e or the communication memory 33e in the transmitter 2 or the receiver 3 and referring to the communication memory. In this case, the transmitter 2 and the receiver 3 may periodically attempt wireless communication.

By adopting this procedure, the CEC-compatible device recognizes this condition as a state equivalent to the HDMI cable being dropped, and after communication is resumed, the CEC-compatible device can be operated without collapsing.

< Another exemplary configuration of Wireless Transmission System according to the present invention >

Although in the exemplary configuration depicted in the system the transmitter 2 is coupled externally to the STB1 and the receiver 3 is coupled externally (externally connected) to the monitor 4 as shown in fig. 1, an embedded configuration may be employed for one or both of the transmitter 2 and the receiver 3. The CEC control section of the receiver 3 may be embedded in the monitor 4 and connected to the CEC control section provided in the monitor 4. The wireless connection section 34 of the receiver 3 may be embedded as well as the CEC control section. The CEC control section of transmitter 2 may be embedded in STB1 and connected to a CEC control section provided in STB 1. The wireless connection section 24 of the transmitter 2 may be embedded as well as the CEC control section.

< Wireless Transmission method according to the present invention >

The present invention may adopt a wireless transmission method in the following form as a method for transmitting/receiving a CEC message using a program or information. The program or information may be distributed via a portable recording medium, broadcast waves, an internet line, or the like. Describing with the exemplary configuration of fig. 1, the wireless transmission method according to the present invention uses the receiver 3 and the transmitter 2 to transmit/receive CEC messages between the monitor 4 and the STB1 through wireless communication between the receiver 3 and the transmitter 2, the receiver 3 having a CEC control section capable of transmitting/receiving CEC messages to/from the monitor 4, and the transmitter 2 having a CEC control section capable of transmitting/receiving CEC messages to/from the STB 1.

The wireless transmission method is mainly characterized by comprising the steps of transmitting/receiving, by the CEC control section of the receiver 3, a CEC message to/from the CEC control section provided in the monitor 4 using a logical address corresponding to the device type of the STB1, and transmitting/receiving, by the CEC control section of the transmitter 2, a CEC message to/from the CEC control section provided in the STB1 using a logical address corresponding to the device type of the monitor 4. Other applications are the same as described for the wireless transmission system and will not be described.

Reference numerals

An STB; 2. a transmitter; 3. a receiver; 4. a monitor; 5. a remote controller; 11, 21, 31, 41: a wired connection portion; 12, 22, 32, 42: a control section; 13, 23, 33, 43: a storage section; 14, 44: a main control section; 15. a tuner section; 23a, 33 a: a CEC driver; 23b, 33 b: a CEC management program; 23c, 33 c: a response table; 23d, 33 d: a wireless communication driver; 23e, 33 e: a communication memory; 24, 34: a wireless connection section; 45. a video processing section; 46. a display section; and 47. light receiving section.

Claims (6)

1. A wireless transmission system, comprising:

a first wireless communication device having a CEC control portion capable of transmitting/receiving CEC messages to/from a display device in HDMI; and

a second wireless communication device having a CEC control portion capable of transmitting/receiving CEC messages to/from the AV device in HDMI,

the wireless transmission system performs transmission/reception of a CEC message between the display apparatus and the AV apparatus through wireless communication between the first wireless communication apparatus and the second wireless communication apparatus,

wherein the CEC control portion of the first wireless communication device transmits/receives a CEC message to/from the CEC control portion provided in the display device using a logical address corresponding to the device type of the AV device,

the CEC control section of the second wireless communication device transmits/receives a CEC message to/from the CEC control section provided in the AV device, using a logical address corresponding to the device type of the display device.

2. The wireless transmission system of claim 1,

the first wireless communication device determines whether transmission to the AV device is necessary depending on the type of the CEC message received from the display device, and performs wireless transmission to the second wireless communication device only for the CEC message determined to be necessary for transmission, an

The second wireless communication device determines whether transmission to the display device is necessary depending on the type of the CEC message received from the AV device, and performs wireless transmission to the first wireless communication device only for the CEC message for which it is determined that transmission is necessary.

3. The wireless transmission system according to claim 1 or 2,

the first wireless communication device determines whether the CEC message received from the display device needs to have a response time period to the display device shorter than a predetermined time, and makes a response to the CEC message that needs to have a shorter response time period, instead of the AV device responding to the display device,

the second wireless communication device determines whether the CEC message received from the AV device needs to have a response time period to the AV device shorter than a predetermined time, and makes a response to the CEC message that needs to have a shorter response time period, instead of the display device responding to the AV device.

4. Wireless transmission system according to one of the claims 1 to 3,

when in a condition in which the first wireless communication device cannot perform wireless communication with the second wireless communication device, the CEC control portion of the first wireless communication device does not return an ACK bit to the display device even when receiving a CEC message from the display device, an

When in a condition in which the second wireless communication apparatus cannot perform wireless communication with the first wireless communication apparatus, the CEC control portion of the second wireless communication apparatus does not return the ACK bit even when receiving a CEC message from the AV apparatus.

5. Wireless transmission system according to one of the claims 1 to 4,

the CEC control portion of the first wireless communication device is externally connected to the CEC control portion provided in the display device or embedded in the display device and connected to the CEC control portion provided in the display device, and

the CEC control section of the second wireless communication device is externally connected to the CEC control section provided in the AV device, or is embedded in the AV device and connected to the CEC control section provided in the AV device.

6. A wireless transmission method for performing transmission/reception of a CEC message between a display device and an AV device through wireless communication between a first wireless communication device having a CEC control portion capable of transmitting/receiving a CEC message to/from the display device with HDMI and a second wireless communication device having a CEC control portion capable of transmitting/receiving a CEC message to/from the AV device with HDMI, using the first wireless communication device and the second wireless communication device, the method comprising the steps of:

transmitting/receiving, by the CEC control part of the first wireless communication device, a CEC message to/from the CEC control part provided in the display device using a logical address corresponding to the device type of the AV device, an

Transmitting/receiving, by the CEC control portion of the second wireless communication device, a CEC message to/from the CEC control portion provided in the AV device using a logical address corresponding to the device type of the display device.