JP4037384B2 - Wireless communication apparatus, wireless AV system, wireless transmission method, operation control program, and recording medium recording the program - Google Patents

Description

  The present invention relates to a wireless communication apparatus, a wireless AV system, a wireless transmission method, an operation control program, and a recording medium on which the program is recorded.

  In recent years, with the explosive spread of the Internet, the number of cases in which a LAN (Local Area Network) is constructed in an office, a home, or the like is increasing. Thanks to the advancement of digital wireless communication technology, the need for so-called wireless LAN, which builds a wireless LAN due to the inconvenience of cabling, has increased greatly. In addition, the mobile environment represented by mobile terminals such as laptop computers It also helps us to use it below, and in the future, a considerable number of disseminated vehicles are expected. As a typical technology of this wireless LAN, there is IEEE 802.11 which has already been standardized by the Institute of Electrical and Electronics Engineers (IEEE). This standardized technology defines Ethernet from the physical layer to the MAC (Media Access Control) layer, which is the lower layer of the data link, in the OSI model, and is a wired LAN transmission path. In addition, it is a specification that can provide a roaming function as an additional function because it is wireless.

  By the way, in a wireless network, when a transmitter and receiver are communicating at a specific frequency (communication channel), when another transmitter / receiver pair uses the same communication channel, the data transmission bandwidth is reduced. Therefore, it is necessary to automatically change the device that uses the communication channel later to a free communication channel.

  As a wireless communication device for changing a communication channel, for example, in Patent Document 1, a wireless communication unit is provided with a 2.4 GHz band front end circuit and a 5 GHz band front end circuit, and two 2.4 GHz band and 5 GHz band signals are provided. By adapting to the frequency band, the wireless LAN system greatly increases the number of channels that can be set simultaneously in the same area, and reduces the possibility that the communication link will be interrupted by jamming radio waves.

Also, in Patent Document 2, information communication devices capable of information communication are searched to establish information communication, contents that can be processed by the terminal of the information terminal device are determined and collected, and a content information list is generated. An information processing system is disclosed. This information processing system displays at least one of compression format information, bit rate information, sampling rate information, and extension information on a display unit.
JP 2002-33676 A (FIG. 1) Japanese Patent Laying-Open No. 2003-50589 (FIG. 1)

  However, in such a conventional wireless communication device, when the communication state deteriorates, the error rate of data increases and the number of retransmission requests increases. Unusable block noise appears. In such a case, if the transmission rate (bit rate) is lowered, the error rate is reduced and the block noise can be reduced, but the image quality is deteriorated.

  The present invention has been made in view of such problems, and even when the communication state deteriorates, the deterioration of video and audio data can be minimized and data transmission can be maintained as much as possible. An object is to provide a wireless communication apparatus, a wireless AV system, a wireless transmission method, an operation control program, and a recording medium on which the program is recorded.

  The wireless communication device of the present invention is a wireless communication device that transmits video and audio data at a predetermined bit rate, and a communication status detection means for detecting a communication status, and content identification for identifying a content type of video and audio data to be transmitted Means and transmission rate setting means for setting a transmission rate of video and audio data to be transmitted based on the detected communication state and the identified content type.

  The communication state detection means may detect the communication state based on the field strength of the received radio wave, the error rate, or the number of retransmission requests based on the error rate.

  The communication state detection unit may detect a communication state between wireless communication devices with which communication links are established.

  As a more preferred specific mode, the content identification means identifies at least one of movie, news, drama, and music program content.

  More preferably, the transmission rate setting means sets a bit rate and a maximum number of retransmissions set for each content type.

  More preferably, the transmission rate setting means sets the bit rate and the maximum number of retransmissions at the maximum transfer rate set for each content type, and the bit rate and the maximum number of retransmissions at the minimum transfer rate.

  The video and audio data may be transmitted by an MPEG stream conforming to the MPEG encoding method.

  The video and audio data may be transmitted by an SS wireless method.

Wireless AV system of the present invention is characterized in that a wireless AV system for connecting a plurality of the wireless communication device through a wireless network.

  As a specific aspect, the wireless communication device is a television receiver including a display device and a broadcast receiving tuner and a center device that transmits video and audio data to the display device.

  In the wireless transmission method of transmitting video and audio data at a predetermined bit rate, the wireless transmission method of the present invention detects a communication state, and identifies a content type of video and audio data to be transmitted. The method includes a step of setting a transmission rate of video and audio data to be transmitted based on the communication state, and a step of changing the set transmission rate based on the identified content type.

  Further, the present invention provides a wireless transmission method for transmitting video and audio data at a predetermined bit rate, a step of detecting a communication state, a step of identifying a content type of video and audio data to be transmitted, and a detected communication state A program for causing a computer to execute a step of setting a transmission rate of video and audio data to be transmitted and a step of changing the set transmission rate based on the identified content type.

  Furthermore, the present invention provides a wireless transmission method for transmitting video and audio data at a predetermined bit rate, a step of detecting a communication state, a step of identifying a content type of video and audio data to be transmitted, and a detected communication state And recording a program for causing a computer to execute a step of setting a transmission rate of video and audio data to be transmitted and a step of changing the set transmission rate based on the identified content type. This is a computer-readable recording medium.

  As described above in detail, according to the present invention, even when the communication state deteriorates, the deterioration of video and audio data can be minimized and data transmission can be maintained as much as possible. Thereby, it is possible to maintain the optimum communication state as much as possible in the entire network.

  Hereinafter, preferred embodiments of a wireless communication apparatus, a wireless AV system, and a wireless transmission method according to the present invention will be described in detail with reference to the accompanying drawings.

  First, the basic concept of the present invention will be described.

  FIG. 1 is a diagram showing a basic configuration of a wireless communication apparatus provided with a transmission rate changing method of the present invention. In FIG. 1, a transmitter 100 includes a transmission unit 110 that transmits video and audio data (hereinafter referred to as AV data), a reception unit 120 that receives AV data, a transmission rate determination unit 130 that determines a transmission rate from the received data, AV data output means 140 for outputting transmission AV data, transmission rate changing means 150 for changing the transmission rate based on the content information added to the received data, and content information indicating the content of the transmission AV data in the transmission AV data. Content information adding means 160 to be added and packet generating means 170 for generating a packet from AV data to which the content information is added are configured.

  The receiver 200 includes a receiving unit 210 that receives AV data, a transmitting unit 220 that transmits AV data according to the determined transmission rate, a decoding unit 230 that decodes the received data, and an error that determines an error rate of the decoded received data. Rate determining means 240, content adding means 250 for adding content information to transmission AV data, radio wave state determining means 260 for determining the radio wave state, and transmission rate determining means 270 for determining the transmission rate according to the determination results of the radio wave state determining means 260 It is configured with.

  The transmitter 100 is a wireless center of a liquid crystal TV described later, and the receiver 200 is a TV body.

  As a technique for realizing a wireless AV system, for example, there is a standard specification called HAVi (Home Audio / Video Interoperability) Architecture that has been standardized in January 2000. As described in the HAVi V1.0 Specification version overview (1.1 General's 1.1 Scope), this specification connects home appliances and computers, and allows a user to use another device to connect another device. Provides an interface for operation. In the HAVi specification, as an example, it is assumed that a network is constructed by household appliances compliant with IEEE 1394 and IEC (International Electrotechnical Commission) 61883. Moreover, as in the same outline part of the specification, all users can freely use devices connected to the network realized by HAVi. In this way, by connecting AV devices in the home and constructing an AV network, the user can use any combination of devices in remote rooms.

  In addition to such a home AV network, the transmitter 100 and the receiver 200 are, for example, a mobile phone / PHS (Personal Handy-Phone System) or a personal digital assistant (hereinafter referred to as PDA (Personal Digital Assistants) that performs wireless communication. ))) Or the like.

  In the above configuration, when the communication state deteriorates, if the transmission rate (bit rate) is lowered, the error rate can be reduced and noise can be reduced, but the image quality is deteriorated. The inventors focused on the content of data to be transmitted and considered changing the bit rate according to the content. There are content that can be tolerated even if a little block noise is superimposed (for example, still images, image data close to still images, news data, etc.), and content that is better moving smoothly even with poor image quality (for example, sports program data) The bit rate is varied according to the contents.

  As described above, when the communication state changes (especially when it deteriorates), control is performed to vary the bit rate according to the content of the content of the transmission AV data, instead of uniformly reducing the bit rate. In FIG. 1, the transmission rate changing unit 150 of the transmitter 10 or the transmission rate determining unit 270 of the receiver 200 executes transmission rate change control based on the content content.

  FIG. 2 is a block diagram showing a configuration of a wireless communication apparatus and a wireless AV system according to the embodiment of the present invention based on the above basic concept. This is an example in which the present invention is applied to a display-separated wireless TV receiver as the wireless communication apparatus and wireless AV system of this embodiment.

  In FIG. 2, a wireless AV system 1 includes a wireless center unit (hereinafter referred to as a wireless center) 2 as a base device and a television (TV) main unit (hereinafter referred to as a TV main body) 3 as a portable terminal. The wireless center 2 (wireless communication device, center device) and the TV body 3 (wireless communication device, display device) are paired to form a wireless transmission network.

  The wireless center 2 includes a BS terminal 11, a U / VHF antenna terminal 12, and a diversity terminal 13, and a video 1 input terminal 14 with an S terminal for connecting devices such as a digital VTR and a DVD player, a decoder input / video 2 An input terminal 15, a monitor / BS output / video 3 input terminal 16, an AC power supply unit 17 and a Car-DC power supply unit 18 are provided.

  The TV main body 3 includes a TV output / video 4 input terminal 21 for connecting devices such as a digital VTR and a DVD (Digital Versatile Disc) player, an AC power supply unit 22 and a Car-DC power supply unit 23.

  The TV main body 3 is a thin display device that is separable from the wireless center 2 and can be carried or carried by a built-in battery. The display device is a wide concept including the display device and is not limited by the display mechanism. In this specification, the TV main body 3 mainly has a display function, an acoustic function, and the like, while the wireless center 2 mainly stores a control function for controlling the tuner unit and the TV main body 3. The TV main body 3 according to the present embodiment will be described using a liquid crystal television as an example of a thin display device.

  Data is transmitted and received between the wireless center 2 and the TV main body 3 by an SS (Spread Spectrum) wireless system compliant with the IEEE 802.11 standard. Recently, the 5 GHz band is released as a frequency band, and a mode using the 5 GHz band instead of the 2.4 GHz band may be used. Data transmission from the wireless center 2 to the TV main body 3 uses moving picture expert group (MPEG) 2 video compression format to transmit moving image transmission, DVD-Video, and digital broadcasting over a communication line exceeding 10 Mbps. Further, command transmission between the wireless center 2 and the TV main body 3 is performed by the SS wireless method.

  When applying to an actual application including MPEG video and MPEG audio encoded streams (bit strings) and other encoded streams, the encoded streams are multiplexed and integrated into a single unit including synchronization. At the same time, it is necessary to make the stream a data format conforming to a specific physical format or protocol possessed by the storage medium or network.

  The MPEG2 system includes a program stream (MPEG2-PS, PS: Program Stream) that constitutes one program, and a transport stream (MPEG2-TS, TS: Transport Stream) that can constitute a plurality of programs, as in MPEG1. There is.

  The MPEG stream is a byte stream that is byte-aligned for each unit such as a header although there are many 1-bit flags. As a structure common to the entire MPEG system, the data portion that is not fixed length is preceded by information indicating the length. If unnecessary, that portion is skipped or the head of the next data group is confirmed and trusted. It has a data structure that enables highly-separated separation processing.

  An apparatus for receiving compressed video and audio signals in conformity with the MPEG2 encoding system is designed to receive video and audio sampling frequencies on the encoding side in order to prevent overflow and underflow of video and audio data on the decoding side. And the video, audio sampling frequency or STC (System Time Clock) on the decoding side must be matched.

  Therefore, the decoding apparatus uses PCR (Program Clock Reference) or SCR (System Clock Reference) defined by the MPEG2 system standard (ISO / IEC standard 13818-1). Thus, the video and audio sampling frequencies on the encoding side are matched with the video and audio sampling frequencies on the decoding side.

  FIG. 3 is a block diagram showing a configuration of the wireless center 2 of the wireless AV system.

  In FIG. 3, a wireless center 2 is connected to a BS terminal 11 and receives and selects a BS broadcast by a channel selection signal, and a U / VHF broadcast by a channel selection signal connected to a U / VHF antenna terminal 12. A U / VHF tuner 32 that receives and selects, a video / audio demodulator 33 that demodulates a video / audio (AV) signal received and selected by the BS tuner 31 or the U / VHF tuner 32, and an audio switching signal. Audio switching unit 34 for switching between received audio and information related to a program such as an EPG (Electrical Program Guide), video / audio information received by a source selection signal, information related to a program, video 1 input terminal 14, decoder A first selector 3 for selecting external input information from the input / video 2 input terminal 15 and the monitor / BS output / video 3 input terminal 16 An SS transmission unit 36 (communication means) that transmits / receives a TV command, converts the data selected by the first selector 35 into an MPEG2 video compression format, and transmits the data to the TV body 3 by the SS wireless method; A wireless center microcomputer (hereinafter referred to as a microcomputer) 37 (content identification means, transmission rate setting) which transmits a signal 41, an audio switching signal 42, a source selection signal 43, etc., and transmits / receives a TV command 44 to control the entire apparatus. Means), a control program for the wireless center microcomputer 37, communication control data, and an EEPROM (electrically erasable programmable ROM) which is an electrically rewritable non-volatile memory for storing various data of MPEG rates set for each content. 38.

  The wireless center 2 may include a plurality of broadcast receiving tuners (two in this case), and at least one of the plurality of BS tuners 31 and the U / VHF tuner may be a tuner capable of receiving terrestrial digital broadcasting.

  The SS transmission unit 36 includes an A / D conversion unit 51 that converts the data selected by the first selector 35 into a digital signal, an MPEG2 encoder 52 that converts the data into an MPEG2 video compression format, and transmission data according to the SS wireless system. An SS radio transmission engine 53 including an SS radio device and a radio control unit for transmission, and each part of the SS transmission unit are controlled, and a first SS-CPU 54 (communication state detection means) for detecting a radio wave state is provided. .

  The EEPROM 38 stores the MPEG rate set for each content in a table as shown in FIG. Various specifications in the wireless center 2 and the TV main body 3 can be changed by changing a program written in the EEPROM 38. That is, recently, in order to avoid the time loss of changing the mask ROM for each debugging of the system development, the program ROM is a non-volatile memory, for example, EPROM, EEPROM, and the time for program development / modification time is greatly reduced. . Further, if the program is downloaded and the program contents of the EEPROM are rewritten, it is possible to easily upgrade functions or change functions.

  The SS wireless transmission engine 53 has a transmission function for transmitting an MPEG2 stream, a command, and the like to an SS reception unit 61 (described later in FIG. 4) of the TV main body 3 and a reception function for receiving a command and the like from the SS reception unit 61. Prepare.

  In particular, the first SS-CPU 54 detects a radio wave state detection that detects the communication state (the strength of the radio wave, the interference of the communication path) between the wireless center 2 and the TV body 3 by a retransmission request based on the electric field strength of the received radio wave and the error rate. A function as a means is provided. Information indicating the detected radio wave state is sent to the wireless center microcomputer 37 as a TV command 44. In the present embodiment, the configuration in which the first SS-CPU 54 of the wireless center microcomputer 37 has the above-described radio wave state detection function is shown. However, the second SS-CPU 84 of the TV main body 3 has the same function and is detected. A mode in which information indicating the radio wave state is transmitted from the TV main body 3 to the TV main body 3 may be used. Alternatively, both the first SS-CPU 54 and the second SS-CPU 84 may have a radio wave state detection function. Furthermore, the aspect which the TV microcomputer 64 or the wireless center microcomputer 37 performs the said electromagnetic wave state detection function may be sufficient.

  The wireless center microcomputer 37 controls the entire apparatus, identifies the content type of video and audio data to be transmitted based on the EPG, and determines the transmission rate of the video and audio data to be transmitted based on the detected communication state. In addition to setting, transmission rate change control is performed to change the set transmission rate based on the identified content type. A specific example of the transmission rate change control will be described later with reference to FIG.

  FIG. 4 is a block diagram showing a configuration of the TV main body 3 of the wireless AV system.

  In FIG. 4, the TV main body 3 receives and transmits the TV command and receives the MPEG2 stream and command transmission data transmitted from the SS transmission unit 36 of the wireless center 2, and decodes (restores) the received MPEG2 stream to the original data. ) SS receiving unit 61 (communication means), a second selector 62 for selecting data restored by the SS receiving unit 61 and an AV signal input from the outside via the TV output / video 4 input terminal 21; The TV display unit 63 including an LCD or the like that displays a video signal and outputs an audio signal transmits / receives a TV command 71, and transmits a source selection signal 72, an OSD (on-screen display) 73, etc. TV microcomputer 64 for controlling, control program for TV microcomputer 64, communication EEPROM 65, which is an electrically rewritable non-volatile memory for storing various data such as control data and a communication channel change program, and a remote controller for receiving control commands from a remote control device (not shown) (hereinafter referred to as a remote control device). A light receiving unit 66, a battery 67, and a battery charger microcomputer 68 that controls charging / discharging of the battery 67 are provided.

  The SS reception unit 61 includes an SS radio reception engine 81 including an SS radio and a radio control unit that receives data transmitted by the SS radio system, an MPEG2 decoder 82 that decodes the received MPEG2 stream, and an analog signal for the decoded data. The D / A conversion unit 83 that converts the signal to the signal and each part of the SS receiving unit are controlled, and the second SS-CPU 84 (communication state detection means) that detects the radio wave state is provided.

  The SS radio reception engine 81 has a reception function for receiving an MPEG2 stream, a command and the like from the SS transmission unit 36 of the wireless center 2 and a transmission function for transmitting a command and the like from the SS reception unit 61.

  The TV microcomputer 64 has an OSD generation function unit inside, and displays information such as a channel, time, and volume on a screen of a television or the like. In an electronic apparatus such as a video apparatus such as a TV or a video conference system, information such as a channel, time, and volume is generally displayed on a TV screen. The OSD data is not an image, but is stored in a format called a bitmap. This bitmap is converted into YUV format pixel values represented by Y, Cb, and Cr, and the converted pixels are used for television broadcasting or the like. Is superimposed on the original image. Further, if an image playback device such as a DVD (not shown) is connected to the TV output / video 4 input terminal 21, OSD display is possible by superimposing the playback image on the display screen.

  Although not shown, the TV main unit 3 includes a speaker, a key input unit, a slot for inserting / removing a card type external expansion storage medium, and the like. It is good also as a structure which reads directly. The card-type external extended storage medium includes, for example, an SRAM (Static RAM) card that holds information written by power backup, a compact flash (registered trademark) (CF) including a flash memory that does not require power backup, smart media, memory It is a micro hard disk drive (HDD) or the like that can be mounted on a stick, or a compact flash (registered trademark) or a PC card Type II.

  The remote control light receiving unit 66 is an optical communication port unit that uses IR (Infrared Rays) and receives optical signals from a remote control device that performs various operations on the TV body 3 or the wireless center 2. Specifically, it is a standard for transmitting data using infrared rays, an I / O port for performing optical communication in accordance with IrDA (Infrared Data Association), ASK, or the like, or a wireless communication port using radio waves. .

  The battery 67 supplies predetermined power to each part of the TV main body 3. When the battery 67 is in a chargeable state, the battery charger microcomputer 68 detects, for example, that the TV main body 3 is attached to the wireless center 2 or other cradle, and supplies a power supply terminal ( In either case, charging / discharging is controlled via a not shown). Specifically, the battery charger microcomputer 68 integrates the discharge current of the battery pack and starts charging when it is determined that the remaining capacity of the battery pack has become a predetermined value or less. The charging is stopped when it is determined that the battery pack has been fully charged. The charged battery 67 becomes the main power source of the portable TV when the TV main body 3 is disconnected from the commercial power source, and supplies power to each part of the main body.

  The operation of the wireless AV system configured as described above will be described below.

  FIG. 5 is a flowchart showing the transmission rate changing operation of the wireless AV system, which is executed by the wireless center microcomputer 37. In the figure, S indicates each step of the flow.

  FIG. 6 is a diagram showing a specific configuration example of the MPEG rate referred to when AV data is transmitted.

  In FIG. 6, the MPEG rate (Mbps) and the maximum number of retransmissions are set for the MPEG rate for the setting value set for each content type. Content includes movie, news, drama, and music program types, and has a maximum / minimum transfer rate setting value and an MPEG rate (Mbps) for each type. For example, when the content is “movie”, the set value of the maximum transfer rate is “0x11”, the maximum transfer rate is 6.67 (Mbps), the set value of the minimum transfer rate is “0x0B”, and the minimum transfer rate is 5.63. (Mbps). The maximum transfer rate is a rate when the communication state is good, and the minimum transfer rate is a rate when the communication state is deteriorated.

  Also, as shown in the example of the MPEG rate in FIG. 6, the MPEG rate (Mbps) and the maximum number of retransmissions are set according to the set value. For example, when the contents are “movie” and “news”, the setting value of the maximum transfer rate used when the communication state is good is “0x11” and the maximum number of retransmissions is “3”, but the communication state is the same. When it gets worse, the setting value of the minimum transfer rate of the content “movie” is “0x0B”, the maximum number of retransmissions is “5”, the setting value of the minimum transfer rate of the content “news” is “0x05”, and the maximum number of retransmissions is “15”. Is set. In the case of “movies”, if the communication state deteriorates, it is meaningless to transmit until the video quality is greatly reduced. Therefore, the transmission rate is kept at a predetermined level of 5.63 (Mbps). On the other hand, in the case of “news”, data transmission is performed as much as possible by setting the maximum number of retransmissions to “15” instead of greatly reducing the minimum transfer rate to 3.48 (Mbps) with emphasis on information transferability rather than video quality. “Drama” and “music program” have an intermediate transfer rate between “movie” and “news”. The content type and the MPEG rate are examples and are not limited to these. In this way, the bit rate is made variable according to the contents by changing the communication state.

  In the flow of FIG. 5, first, the communication state between the wireless center 2 and the TV main body 3 is detected in flow step S1, and the content of AV data to be transmitted is identified in step S2. This content is identified by the video / audio demodulator 33 shown in FIG. 3 based on information about the program such as EPG extracted from the AV data. Here, as shown in FIG. 6, the content types of movies, news, dramas, and music programs are identified. Next, the transmission rate and the maximum number of retransmissions are set based on the radio wave state detected in step S3, and the transmission rate and the maximum number of retransmissions set in step S4 are determined according to the content type with reference to the MPEG rate in FIG. To change. Next, in step S5, a transmission AV data packet is generated, this packet is transmitted at the set / changed transmission rate, and this flow is finished.

  As described above, the wireless AV system 1 according to the present embodiment includes the wireless center 2 as a base device and the TV main body 3, and the wireless center 2 includes the BS tuner 31 and the U / VHF tuner 32. A video / audio demodulator 33 that demodulates the received / selected video / audio signal, an audio switching unit 34 that switches between audio received by the audio switching signal and information related to a program such as EPG, and AV data in MPEG2 video compression format The SS transmission unit 36 for transmitting to the TV main body 3 by the SS wireless system, the wireless center microcomputer 37 for controlling the entire apparatus, the EEPROM 38 for storing the MPEG rate set for each content, and the electric field intensity of the received radio wave , Between the wireless center 2 and the TV main unit 3 by a retransmission request based on the error rate The wireless center microcomputer 37 includes a first SS-CPU 54 that detects the communication state, and the wireless center microcomputer 37 identifies the content type of the video and audio data to be transmitted based on the EPG, and the video to be transmitted based on the detected communication state Since the transmission rate of the audio data is set and the transmission rate change control for changing the transmission rate set with reference to the MPEG rate shown in FIG. 6 is performed based on the identified content type, the communication state has changed. Sometimes (especially when it deteriorates) even if the communication state deteriorates by changing the bit rate according to the content of the AV data content instead of lowering the bit rate uniformly as in the conventional example It is possible for data that requires information transmission, such as news programs, with minimal degradation of video and audio data. It is possible to maintain the data transmission.

  Note that the wireless communication device and the wireless AV system of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. For example, a portable TV is used as a wireless AV device, but the present invention is not limited to a TV receiver, and can be applied to a device having a wireless communication function or a combination thereof. For example, as an AV device, in addition to a VTR (Video Tape Recorder), a recording / reproducing apparatus for recording on an HDD or a DVD may be used. In addition, as a device that can transmit and receive data, a device that is integrated with an information device function represented by a personal computer may be used, and it can be applied to all systems. The contents of the transmitted / received data may be anything.

  In this embodiment, the TV receiver has been described. However, the present invention is not limited to this, and as described above, the present invention can be applied to a tuner, a personal computer, and other AV devices using the tuner.

  In addition, the types of processing units and the like, the type / format of setting information, and the like constituting the wireless communication device and the wireless AV system are not limited to the above-described embodiments. In particular, it is suitable for application to a device that complies with HAVi.

  The AV data is transmitted by an MPEG stream conforming to the MPEG2 encoding system, but the data transmission can be similarly applied to data transmission other than an MPEG stream or an MPEG stream according to another MPEG system. Further, the content type and the MPEG rate shown in FIG. 6 are examples and are not limited to these.

  In this embodiment, the names wireless communication device, wireless AV system, and wireless transmission method are used. However, this is for convenience of explanation, and may be a wireless communication device, an AV device, an information communication method, or the like.

  The wireless communication device and the wireless AV system described above are also realized by a program for causing the wireless communication device and the wireless AV system to function. This program is stored in a computer-readable recording medium. In the present invention, as the recording medium, the main memory itself may be a program medium, or a program reading device is provided as an external storage device and can be read by inserting the recording medium therein. May be. In either case, the stored program may be configured to be accessed and executed by the CPU, or in any case, the program is read and the read program is not shown in a program storage area. The program may be downloaded and executed by the program. It is assumed that this download program is stored in the main device in advance.

  Here, the program medium is a recording medium configured to be separable from the main body, such as a tape system such as a magnetic tape or a cassette tape, a magnetic disk such as a floppy (registered trademark) disk or a hard disk, or a CD-ROM / MO /. It may be a medium carrying a fixed program including a disk system of an optical disk such as MD / DVD, a card system such as an IC card / optical card, or a semiconductor memory such as a mask ROM, EPROM, EEPROM, flash ROM or the like. .

  Furthermore, although not shown in the figure, when a means capable of connection to an external communication network is provided, the program is fluidly supported so that the program is downloaded from the communication network via the communication connection means. It may be a medium. When the program is downloaded from the communication network in this way, the download program may be stored in the main device in advance, or may be installed from another recording medium. The content stored in the recording medium is not limited to a program, and may be data.

It is a figure which shows the basic composition of a radio | wireless communication apparatus provided with the transmission rate change method of the radio | wireless communication apparatus and wireless AV system of embodiment of this invention. It is a block diagram which shows the structure of the radio | wireless communication apparatus and wireless AV system of embodiment of this invention. It is a block diagram which shows the structure of the wireless center of the radio | wireless communication apparatus and wireless AV system of this Embodiment. It is a block diagram which shows the structure of TV main body of the radio | wireless communication apparatus and wireless AV system of this Embodiment. It is a flowchart which shows the transmission rate change operation | movement of the radio | wireless communication apparatus and wireless AV system of this Embodiment. It is a figure which shows the specific structural example of the MPEG rate referred at the time of AV data transmission of the radio | wireless communication apparatus and wireless AV system of this Embodiment.

Explanation of symbols

1 Wireless AV System 2 Wireless Center Unit (Wireless Center) (Radio Communication Device, Center Device)
3. Television main unit (TV main unit) (wireless communication device, display device)
11 BS terminal 12 U / VHF antenna terminal 13 Diversity terminal 14 Video 1 input terminal with S terminal 15 Decoder input / Video 2 input terminal 16 Monitor / BS output / Video 3 input terminal 17 AC power supply unit 18 Car-DC power supply unit 21 TV Output / video 4 input terminal 22 AC power supply unit 23 Car-DC power supply unit 31 BS tuner 32 U / VHF tuner 33 Video / audio demodulation unit 34 Audio switching unit 35 First selector 36 SS transmission unit (communication means)
37 Wireless Center Microcomputer (Wireless Center Microcomputer)
(Content identification means, transmission rate setting means)
38,65 EEPROM
51 A / D converter 52 MPEG2 encoder 53 SS wireless transmission engine 54 SS-CPU
61 SS receiving unit (communication means)
62 second selector 63 TV display unit 64 TV microcomputer 66 remote control light receiving unit 67 battery 68 battery charger microcomputer 81 SS wireless reception engine 82 MPEG2 decoder 83 D / A conversion unit 84 second SS-CPU (communication state detection means)
100 transmitter (wireless communication device)
110, 220 Transmission means 120, 210 Reception means 130 Transmission rate determination means 140 AV data output means 150 Transmission rate change means 160 Content information addition means 170 Packet generation means 200 Receiver (wireless communication apparatus)
230 Decoding unit 240 Error rate determining unit 250 Content adding unit 260 Radio wave state determining unit 270 Transmission rate determining unit

Claims (13)

In a wireless communication device that transmits video and audio data at a predetermined bit rate,
Communication state detecting means for detecting a communication state;
Content identification means for identifying the content type of video and audio data to be transmitted;
Transmission rate setting means for setting a transmission rate of video and audio data to be transmitted based on the detected communication state and the identified content type ;
The transmission rate setting means sets a bit rate set for each content type and a maximum number of retransmissions . In a wireless communication device that transmits video and audio data at a predetermined bit rate,
Communication state detecting means for detecting a communication state;
Content identification means for identifying the content type of video and audio data to be transmitted;
Transmission rate setting means for setting a transmission rate of video and audio data to be transmitted based on the detected communication state and the identified content type;
The transmission rate setting means sets the bit rate and the maximum number of retransmissions at the maximum transfer rate set for each content type, and sets the bit rate and the maximum number of retransmissions at the minimum transfer rate . The communication state detection unit, the field strength of the received radio wave, or an error rate, or a wireless communication device according to claim 1 or 2, characterized in that detecting the communication state by the number of retransmission requests based on the error rate. The wireless communication device according to any one of claims 1 to 3, wherein the communication state detection unit detects a communication state between wireless communication devices with which a communication link is established. The content identification means, movies, news, drama, of the content of the music program, the radio communication apparatus according to any one of claims 1 to 4, wherein identifying one or more at least one. The video and audio data, the radio communication apparatus according to any one of claims 1 to 5, characterized in that transmitted by the MPEG stream conforming to the MPEG coding method. The video and audio data, the radio communication apparatus according to any one of claims 1 to 6, characterized in that it is transmitted by the SS wireless method. A wireless AV system for connecting a plurality of wireless communication devices through a wireless network,
The wireless communications apparatus, the wireless AV system, being a radio communication device according to any one of claims 1 to 7. 9. The television receiver according to claim 8 , wherein the wireless communication device is a television receiver including a display device and a broadcast receiving tuner, and a center device that transmits video and audio data to the display device. Wireless AV system. In a wireless transmission method for transmitting video and audio data at a predetermined bit rate,
Detecting a communication state;
Identifying the content type of the video and audio data to be transmitted;
Setting the transmission rate of video and audio data to be transmitted based on the detected communication state;
Setting a bit rate and a maximum number of retransmissions set for each content type based on the identified content type;
A wireless transmission method comprising: In a wireless transmission method for transmitting video and audio data at a predetermined bit rate,
Detecting a communication state;
Identifying the content type of the video and audio data to be transmitted;
Setting the transmission rate of video and audio data to be transmitted based on the detected communication state;
The step of setting the bit rate and the maximum number of retransmissions at the maximum transfer rate set for each content type , and the bit rate and the maximum number of retransmissions at the minimum transfer rate based on the identified content type. Wireless transmission method. An operation control program for executing the wireless transmission method according to claim 10 or 11, wherein the operation control program causes a computer to execute the above steps. A computer-readable recording medium in which the operation control program according to claim 12 is recorded.

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