JP2004320762A - Radio communication apparatus, wireless av system, operation control program and recording medium with its program recorded thereon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication apparatus which can improve user's facility of use by eliminating user's sense of incongruity even if the display of an image is not interrupted due to the change, etc. of a communication channel, and to provide a wireless AV system etc. <P>SOLUTION: A TV body 3 includes an SS receiving unit 61 receiving an MPEG 2 stream and a command transmission data transmitted from an SS transmission unit 36 of a wireless center 2 to decode the received MPEG 2 stream, etc., a TV display unit 63 for outputting the image and a voice signal, a TV microcomputer 64 for controlling the apparatus entirety, and a second SS-CPU 84 for detecting a communication state between the wireless center 2 and the TV body 3 by a re-transmission request based on an electric field strength of received radio wave and an error rate. The TV microcomputer 64 OSD displays messages of the interruption of the image and the voice data, changing of a channel, connecting and receiving sensitivity information on the TV display unit 63 based on the communication state. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wireless communication device, a wireless AV system, an operation control program, and a recording medium storing the program.

  2. Description of the Related Art In recent years, with the explosive spread of the Internet, cases where a LAN (Local Area Network) is constructed in offices, homes, and the like have been increasing. With the advance of digital wireless communication technology, the need for so-called wireless LAN, which constructs a wireless LAN, has been greatly increased due to the cumbersome cable wiring, and the mobile environment for mobile terminals typified by notebook computers. Underneath is that it can also be used, and a considerable number of popular vehicles are expected in the future. As a typical technology of the wireless LAN, there is already IEEE 802.11 standardized in IEEE (Institute of Electrical and Electronics Engineers). This standardized technology defines a layer from a physical layer to a MAC (Media Access Control) layer which is a lower layer of a data link in an OSI model, and is a wired LAN transmission path, Ethernet. The specification is such that a roaming function can be provided as an additional function because it is wireless.

  In addition, preparations for a new terrestrial digital broadcast that will replace the analog terrestrial broadcast currently being viewed nationwide are in progress. This digital terrestrial broadcasting was started in the three major metropolitan areas of Kanto, Kinki and Tokai in 2003, and is planned to be expanded nationwide in 2006. Accordingly, the current analog broadcasting will be abolished in 2011.

  ISDB (Integrated Services Digital Broadcasting) is a concept of next-generation integrated digital broadcasting that handles all information such as video, audio, and data as digital data. As specific services of ISDB, digital television broadcasting, digital audio broadcasting, facsimile broadcasting, multimedia broadcasting, and the like have been studied. As an ISDB transmission line, use of a satellite broadcast wave, a terrestrial broadcast wave, or a wired transmission line of a coaxial cable or an optical fiber is considered.

  This terrestrial digital broadcasting technical standard ISDB-T (Terrestrial) adopts OFDM (Orthogonal Frequency Division Multiplexing) which uses a large number of carriers for the modulation method, and uses multiple propagation paths (multipath) such as reflection from a building. Ghost disturbance can also be suppressed. Further, ISDB-T defines a plurality of transmission modes for defining carrier intervals, a modulation method for each carrier, and a plurality of guard intervals in the time axis direction provided for each effective symbol length. Is acceptable. In practice, an optimum format is selected from these services according to services such as fixed reception and mobile reception.

  In ISDB-T, one channel (band of about 5.6 MHz) is divided into 13 segments (1 segment = about 430 kHz), and the modulation method is changed in units of this. Thus, the broadcasting station can arbitrarily determine the signal configuration such as audio broadcasting and high-definition broadcasting, standard fixed broadcasting and mobile broadcasting in one channel.

  Furthermore, ISDB-T incorporates interleaving in the time axis direction, and the radio waves used are also suitable for transmission to mobile objects. Therefore, mobile receivers such as in-vehicle televisions, PDAs (Personal Digital Assistants), and mobile phones One of the great features is that stable reception is possible even with a portable terminal such as the one described above. In the future, services that assume such mobile reception are also expected to be highly expected.

  By the way, in a wireless network, when a transmitter and a receiver are communicating with a specific frequency (communication channel), and when the same communication channel is used by another pair of a transmitter and a receiver, the band of data transmission is reduced. Therefore, devices that use the communication channel later need to automatically change to a vacant 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 to provide two 2.4 GHz band and 5 GHz band. By supporting the frequency band, the number of channels that can be set simultaneously in the same area in the wireless LAN system is greatly increased, and the possibility that the communication link is interrupted by the interfering radio wave is reduced.
JP-A-2002-33676 (FIG. 1)

  However, in such a conventional wireless communication device, when the communication channel is switched, the communication state is interrupted, so that the image is not displayed, and the user has changed the communication channel because the image is interrupted. There was a problem of not knowing.

  The present invention has been made in view of such a problem, and improves user-friendliness by preventing a user from feeling uncomfortable even when display of video is interrupted due to a change in a communication channel or the like. It is an object of the present invention to provide a wireless communication device, a wireless AV system, an operation control program, and a recording medium storing the program.

  Another object of the present invention is to provide a wireless communication device, a wireless AV system, an operation control program, and a recording medium on which the program is recorded, which can maintain an optimal communication state as possible over the entire network.

  A wireless communication device according to the present invention includes a communication unit that transmits and receives a control command including video and audio data or communication channel change information, a communication state detection unit that detects a communication state, and a communication detected by the communication state detection unit. And notifying means for notifying at least the transmission status of the video and audio data based on the state.

  Further, the communication channel may be measured by measuring the time when the communication is interrupted and until a predetermined time elapses after the communication is interrupted.

  The communication means may transmit the video and audio data or the control command by an SS (Spread Spectrum) wireless system.

  The communication means may transmit the video and audio data by an MPEG stream conforming to the MPEG2 encoding method.

  The communication means may be low-power short-range two-way wireless communication.

  Further, as a more preferable specific mode, the communication means is Bluetooth, UWB, or wireless LAN.

  More preferably, the communication state detecting means detects the communication state based on the electric field strength of the received radio wave, the error rate, or the number of retransmission requests based on the error rate.

  More preferably, the communication state detecting means detects a communication state between wireless communication devices with which a communication link has been established.

  Further, the notifying unit notifies at least one of at least one of the video and audio data being interrupted, the communication channel being changed, the connection being established, and the reception sensitivity information including out of communication range. May be used.

  The notification means may be a message display by a display means or a message sounding by a voice output means.

  A wireless AV system according to the present invention is a wireless AV system that connects a plurality of wireless communication devices via a wireless network, wherein the wireless communication device is the wireless communication device according to any one of claims 1 to 10. It is characterized by:

  As a more preferable specific mode, the wireless communication device is a television receiver including a display device, a center device having a broadcast receiving tuner, and transmitting video and audio data to the display device. .

  Also, the present invention provides a method for transmitting and receiving a control command including video and audio data or communication channel change information in a plurality of wireless communication devices constituting a wireless network, detecting a communication state, and detecting a communication state based on the detected communication state. A program for causing a computer to execute at least a control process for notifying the transmission status of the video and audio data.

  Further, the present invention provides, in a plurality of wireless communication devices constituting a wireless network, transmitting and receiving a control command including video and audio data or communication channel change information, detecting a communication state, and based on the detected communication state. A computer-readable recording medium having recorded thereon a program for causing a computer to execute at least a control process for notifying a transmission state of the video and audio data.

  As described in detail above, according to the present invention, even when the display of video is interrupted due to a change in communication channel or the like, it is possible to prevent the user from feeling uncomfortable, and to improve the usability of the user. Can be.

  Further, it is possible to prevent frequent switching of channels and maintain an optimal communication state as possible over the entire network.

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

  FIG. 1 is a block diagram illustrating a configuration of a wireless communication device and a wireless AV system according to an embodiment of the present invention. This is an example in which the wireless communication device and the wireless AV system according to the present embodiment are applied to a display-separated wireless TV receiver.

  In FIG. 1, 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 unit) 3 as a portable terminal. The wireless center 2 (wireless communication device, center device) and the TV main body 3 (wireless communication device, display device) form a pair to form a wireless transmission network.

  The wireless center 2 includes a video 1 input terminal 14 with an S terminal for connecting devices such as a digital VTR and a DVD player to a BS terminal 11, a U / VHF antenna terminal 12, and a diversity terminal 13, and 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 is portable or portable with a built-in battery. , And is not limited by the display mechanism. Further, in this specification, the TV main body 3 mainly has a display function, an audio function, and the like, while the wireless center 2 mainly accommodates a control function for controlling the tuner section, the TV main body 3, and the like. 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 conforming to the IEEE 802.11 standard. Recently, a 5 GHz band has been opened as a frequency band, and a mode in which a 5 GHz band is used instead of the 2.4 GHz band may be used. The data transmission from the wireless center 2 to the TV main body 3 uses a video compression format of MPEG (Moving Picture Expert Group) 2 to transmit moving image transmission, DVD-Video, and digital broadcast over a communication line exceeding 10 Mbps. Command transmission between the wireless center 2 and the TV main body 3 is performed by the SS wireless system.

  When applied to an actual application including an encoded stream (bit string) of MPEG video or MPEG audio, and other encoded streams, the encoded streams including synchronization are multiplexed and integrated into one. At the same time, it is necessary to convert the stream into a data format suitable for a unique physical format or protocol of a storage medium, a network, or the like.

  In the MPEG2 system, a program stream (MPEG2-PS, PS: Program Stream) constituting one program and a transport stream (MPEG2-TS, TS: Transport Stream) capable of constituting a plurality of programs as in MPEG1. There is.

  The MPEG stream is a byte stream that has many 1-bit flags but is byte-aligned for each unit such as a header. As a structure common to the entire MPEG system, information indicating the length is preceded in a data portion that is not a fixed length, and when unnecessary, the portion is skipped, or the head of the next data group is checked and reliable. It has a data structure that allows highly-separable separation processing.

  A device that receives a compressed video and audio signal in conformity with the MPEG2 encoding system requires a video and audio sampling frequency on the encoding side to prevent overflow and underflow of video and audio data on the decoding side. And the video and audio sampling frequencies or STC (System Time Clock) on the decoding side.

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

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

  In FIG. 2, a wireless center 2 is connected to a BS terminal 11 to receive and select a BS broadcast by a tuning signal, and is connected to a U / VHF antenna terminal 12 to transmit a U / VHF broadcast by a tuning signal. A U / VHF tuner 32 for receiving and selecting a channel, a video / audio demodulator 33 for demodulating a video / audio (AV) signal received and selected by the BS tuner 31 or the U / VHF tuner 32, and an audio switching signal An audio switching section 34 for switching between received audio and information on a program such as an EPG (Electrical Program Guide); video / audio information received by a source selection signal; information on a program; video 1 input terminal 14; First selector 3 for selecting external input information from input / video 2 input terminal 15 and monitor / BS output / video 3 input terminal 16 An SS transmission unit 36 (communication means) for transmitting and receiving a TV command, converting the data selected by the first selector 35 into a video compression format of MPEG2, and transmitting the data to the TV main body 3 by the SS wireless system. A wireless center microcomputer (hereinafter referred to as a microcomputer) 37 for transmitting a signal 41, a voice switching signal 42, a source selection signal 43, etc., and transmitting and receiving a TV command 44 to control the entire apparatus; An EEPROM (electrically erasable programmable ROM) 38, which is an electrically rewritable nonvolatile memory for storing various data such as a program, communication control data, and a communication channel change program, is provided.

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

  The SS transmission unit 36 includes an A / D converter 51 that converts the data selected by the first selector 35 into a digital signal, an MPEG2 encoder 52 that converts the data into a video compression format of MPEG2, and transmits the transmission data by the SS wireless system. An SS wireless transmission engine 53 including an SS wireless device and a wireless control unit for transmitting, and a first SS-CPU 54 that controls each unit of the SS transmission unit and detects a radio wave state are provided.

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

  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, an EPROM or an EEPROM, and the program development / correction time is greatly reduced. . Also, if the program is downloaded and the program content of the EEPROM is rewritten, the function can be easily upgraded or changed.

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

  In FIG. 3, the TV main body 3 receives and transmits a TV command, receives an 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 and the like into original data. An 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; A TV display unit 63 (part of a notifying unit), such as an LCD, which displays a video signal and outputs an audio signal, transmits and receives a TV command 71, a source selection signal 72, an OSD (on-screen display) 73, and the like. TV microcomputer 64 (a part of the notifying means) for transmitting the An EEPROM 65, which is an electrically rewritable nonvolatile memory for storing various data such as a control program of the microcomputer 64, communication control data, and a communication channel change program, and a remote control device (not shown) (not shown). And a battery charger microcomputer 68 for controlling charging and discharging of the battery 67.

  The SS reception unit 61 includes an SS radio reception engine 81 including an SS radio and a radio control unit for receiving data transmitted by the SS radio scheme, an MPEG2 decoder 82 for decoding a received MPEG2 stream, and an analog signal for decoding the decoded data. And a second SS-CPU 84 (communication state detecting means) for controlling each part of the SS receiving unit and detecting a radio wave state.

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

  In particular, the second SS-CPU 84 detects a radio wave state that detects a communication state between the wireless center 2 and the TV main body 3 (intensity of a radio wave, disturbance of a communication path) by a retransmission request based on an electric field strength of a received radio wave and an error rate. It has a function as a means. Information indicating the detected radio wave state is sent to the TV microcomputer 64 as a TV command 71. In the present embodiment, the second SS-CPU 84 of the TV main body 3 has a configuration in which the above-described radio wave state detecting function is provided. However, the first SS-CPU 54 of the wireless center 2 has the same function and detects the detected radio wave. A mode in which information indicating the state is transmitted from the wireless center 2 to the TV main body 3 by a command may be used. Alternatively, both the first SS-CPU 54 and the second SS-CPU 84 may have a radio wave state detecting function. Furthermore, a mode in which the TV microcomputer 64 or the wireless center microcomputer 37 performs the radio wave state detection function may be used.

  The TV microcomputer 64 controls the entire apparatus and includes, based on the detected communication state, that the video and audio data are interrupted, that the communication channel is being changed, that the connection is being made, and that the area is out of the communication range. It has a function as notification means for notifying each message of the reception sensitivity information.

  In addition, the TV microcomputer 64 measures the time when the communication is interrupted, and performs communication channel change control for holding the communication channel until a predetermined time elapses after the communication is interrupted. A specific example of the communication channel change control will be described later with reference to FIGS. In addition, the TV microcomputer 64 has an OSD generation function unit therein, and displays information such as a channel, time, and volume on a screen of a television or the like. 2. Description of the Related Art In a video device such as a TV and an electronic device such as a video conference system, information such as a channel, time, and volume is generally displayed on a television screen. The OSD data is stored not in an image but in a format called a bitmap, and the bitmap is converted into YUV format pixel values represented by Y, Cb, and Cr. Is superimposed on the original image. If an image reproducing device such as a DVD (not shown) is connected to the TV output / video 4 input terminal 21, OSD display can be performed by superimposing the reproduced image on the display screen.

  Although not shown, the TV main body 3 is provided with a speaker, a key input unit, a slot for inserting and removing a card-type external expansion storage medium, and the like. May be directly read. The card-type external expansion storage medium is, for example, a Compact Flash (registered trademark) (CF) including a SRAM (Static RAM) card that holds information written by power backup or a flash memory that does not require power backup, smart media, and memory. Stick, or an ultra-compact hard disk drive (HDD) that is about the same size as CompactFlash (registered trademark) or that can be mounted on a PC card Type II.

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

  The battery 67 supplies a predetermined power to each part of the TV main body 3. When the battery 67 becomes chargeable, the battery charger microcomputer 68 detects, for example, that the TV main body 3 is mounted on the wireless center 2 or another cradle or the like, and supplies a power supply terminal ( Charge / discharge control is performed via the respective components (not shown). Specifically, the battery charger microcomputer 68 integrates the discharge current of the battery pack, starts charging when it determines that the remaining capacity of the battery pack has become equal to or less than a predetermined value, and reduces the charging current to the battery pack during charging. The charging is stopped when it is determined that the battery packs have been fully charged and integrated. The charged battery 67 becomes the main power supply of the portable TV when the TV main body 3 is disconnected from the commercial power supply, and supplies electric power to each part of the main body.

  Hereinafter, the operation of the wireless AV system configured as described above will be described.

4 to 7 are diagrams showing state transitions for explaining a communication channel changing method of the wireless AV system. FIG. 4 shows (1) transitions at the time of startup, and FIG. 5 shows (2) normal viewing ( 6 shows a transition from (3) reception sensitivity degradation, and FIG. 7 shows a transition from (4) out of service area. This communication channel change control is executed by the TV microcomputer 64 of the TV main body 3. In the drawings, reference numerals indicate reference numbers for explanation.
(1) Transition at Startup When the power of the TV main body 3 is turned on (No. 101), “Connecting” is displayed on the TV display unit 63 by the OSD output 73 (No. 102), and the system waits for start-up (No. 103). ). The display of “connecting” is displayed only when the RC “ON TIMER” and “OFF TIMER” are input. The “Clock not set” display is not displayed at the time of startup.

  When the TV main unit 3 is started, a channel is selected by receiving a control command from the remote control device (number 104). This tuning operation will be described in detail. As shown in FIG. 3, the TV microcomputer 64 which has received the control command from the remote control device transmits a control command relating to the tuning to the SS receiving unit 61 as a TV command transmission / reception signal 71, The SS receiving unit 61 of the TV main body 3 transmits to the SS transmitting unit 36 of the wireless center 2 shown in FIG. The SS transmission unit 36 transmits the received control command related to channel selection to the wireless center microcomputer 37 as a TV command transmission / reception signal 44. Upon receiving this control command, the wireless center microcomputer 37 transmits a tuning signal 41 to the BS tuner 31 or the U / VHF tuner 32, and the corresponding tuner 31 or 32 performs tuning. As described above, basically, data is sent from the wireless center 2 to the TV body 3 as an MPEG2 stream by the SS wireless system between the wireless center 2 and the TV body 3, but command transmission is performed between the wireless center 2 and the TV body 3. The command data is transmitted and received by the command. The above is an example of command transmission for channel selection, but similar command transmission is performed for voice and source selection.

  Returning to the description of the transition at the time of (1) startup in FIG. 4, the TV microcomputer 64 determines the communication state between the wireless center 2 and the TV main body 3 detected by the second SS-CPU 84 (the strength of radio waves, It is determined whether or not the reception sensitivity is good based on the information of “interference” (No. 105). If the reception sensitivity is good, the mute is released (No. 106), "Connecting" is erased (No. 107), and a transition is made to the transition state of (2) Normal viewing (good reception sensitivity) in FIG. 108). This mute is a non-video / no-sound processing for eliminating noise of video and audio when switching the signal connection.

  As a result, after the power of the TV main unit 3 is turned on, “connected” is displayed on the TV display unit 63 by the OSD output 73 until the channel selection is completed. However, “connected” is displayed immediately because the reception sensitivity is good. Disappears, and the process shifts to (2) normal viewing in FIG.

  If the receiving sensitivity is not good in the determination of the above No. 105, it is determined whether or not the receiving sensitivity has deteriorated (No. 109). If the reception sensitivity is degraded, the mute is released (No. 110), and "The radio wave is hard to reach" is displayed on the TV display unit 63 by the OSD output 73 (No. 111), and (3) in FIG. The state shifts to a transition state from reception sensitivity deterioration (number 112).

  If the reception sensitivity is not degraded in the determination of the above No. 109, it is determined that the reception sensitivity is degraded (No. 113), and if the reception sensitivity is degraded, the mute is not released and the OSD output is outputted to the TV display unit 63 "Out of service area" is displayed by 73 (No. 114), and transition is made to (4) Transition from out of service area in FIG. 7 (No. 115).

As described above, after the TV main unit 3 is turned on, “Connecting” is displayed. If the receiving sensitivity is good, the “Connecting” display disappears. Is out of reach "or" Out of service area "is displayed. Therefore, when switching the communication channel, the user can easily know whether the connection is established, the reception state is poor, the video is interrupted, or the communication terminal has changed the communication channel.
(2) Transition from Normal Viewing (Good Receiving Sensitivity) When in the normal viewing state (No. 201), information on the communication state (intensity of radio waves, disturbance of the communication path) is input by the second SS-CPU 84. Then, the deterioration of the receiving sensitivity is determined (No. 202). If the reception sensitivity is degraded, the "radio wave is difficult to reach" is displayed by the OSD output 73 on the TV display unit 63 (No. 203), and a transition is made to (3) FIG. (No. 204).

If the reception sensitivity is not degraded in the determination of the above No. 202, it is determined whether the reception sensitivity is degraded (No. 205). If the reception sensitivity is degraded, mute is performed (No. 206), "Out of service" is displayed on the TV display unit 63 by the OSD output 73 (No. 207), and the state transitions to (4) Transition from out of service area in FIG. (No. 208). If the reception sensitivity is not degraded in the determination of No. 205, no transition is made as no change (No. 209).
(3) Transition from “The radio wave is hard to reach” (reception sensitivity deterioration) When the reception sensitivity is in the deterioration state (No. 301), the reception sensitivity is changed based on the communication state information from the second SS-CPU 84. It is determined whether or not improvement has been made (No. 302). If the reception sensitivity has been improved, the "radio wave is difficult to reach" display is erased (No. 303), and a transition is made from (2) normal viewing (good reception sensitivity) in FIG. 5 (No. 304). ).

If the reception sensitivity has not been improved in the determination of the above number 302, it is determined whether or not the reception sensitivity has deteriorated (number 305). If the reception sensitivity is degraded, mute is performed (No. 306), and the display is switched from “It is difficult to reach the radio wave” to “Out of service area” by the OSD output 73 on the TV display unit 63 (No. 307). The state transitions from the state (7) (4) outside the service area (number 308). If the reception sensitivity has not deteriorated in the determination of the above number 305, it is determined whether or not a predetermined time (here, 10 seconds) has elapsed (number 309). After 10 seconds have elapsed, the "radio wave is difficult to reach" display is deleted (No. 310). If 10 seconds have not elapsed, it is determined whether the reception sensitivity deterioration state has elapsed for a predetermined time (here, 15 minutes) (No. 311). If 15 minutes have elapsed, it is determined that communication has been interrupted and the predetermined time has elapsed. Judgment is made, and "the radio wave is hard to reach" is displayed again on the TV display unit 63 by the OSD output 73 (number 312). If 15 minutes have not elapsed in the determination of the above number 311, no processing is performed (number 313).
(4) Transition from out of service area When the reception sensitivity is degraded due to “out of service area” (No. 401), it is determined whether or not the reception sensitivity is improved based on the communication state information from the second SS-CPU 84 ( No. 402). If the reception sensitivity is improved, the display is switched to "connecting" because "the radio wave is hard to reach" (number 403), and the channel is selected (number 404). The specific operation of channel selection has already been described. Next, the mute is released (No. 405), the “connected” is erased (No. 406), and a transition is made to the transition state of (2) Normal viewing (good reception sensitivity) in FIG. 5 (No. 407).

  If the reception sensitivity is not improved or is in a deteriorated state in the determination of the above-mentioned number 402, no processing is performed (number 408). At this time, the "out of service" display is continued.

  The above-described state transition will be described in more detail by taking a case where a plurality of transceivers exist as an example.

  FIG. 8 is a diagram illustrating transmission and reception of data by the plurality of transceivers A, B, and C, and FIG. 9 is a diagram illustrating an example of use of communication channels by the plurality of transceivers A, B, and C.

  8 and 9, a transmitter A is, for example, the above-described liquid crystal TV wireless center 2, and a receiver A is a TV main body 3. The transmitters B and C are wireless centers of devices other than the above-described liquid crystal TV of the wireless AV system, and the receivers B and C are their portable terminals and the like.

  As a technology for realizing a wireless AV system, for example, there is a standard specification called HAVi (Home Audio / Video Interoperability) Architecture standardized in January 2000. This specification describes how to connect a household appliance or computer and connect another device using one device, as described in the outline section of the HAVi V1.0 Specification version (1.1 Scope of 1 General). Provides an interface to operate. In the HAVi specification, as an example, it is assumed that a network is constructed using home appliances conforming to IEEE 1394 and IEC (International Electrotechnical Commission) 61883. Further, as described in the outline of the specification, all users can freely use devices connected to the network realized by HAVi. As described above, by connecting the AV devices in the home and constructing the AV network, the user can freely use the devices even in remote rooms.

  In addition to such a home AV network, the transceivers A, B, and C include, for example, a mobile phone / PHS (Personal Handy-Phone System) and a portable information terminal (hereinafter, PDA (Personal Digital Assistants) for performing wireless communication. )).

  On the other hand, a wireless LAN, Bluetooth, and UWB (Ultra Wide Band) are used as a wireless AV system. Wireless LANs are widely used in portable information terminals such as portable notebook personal computers and PDAs having a wireless LAN function. For mobile phones that require lower power consumption, low-power short-range two-way wireless communication systems such as Bluetooth and UWB have attracted attention. Bluetooth is a system that performs short-distance two-way wireless communication between a master (server) and a slave (client), and enables communication between devices anywhere on the earth. Use frequency bands. The communication speed in the current standard is 1 Mbps, and a version upgrade to 2 Mbps is planned in the future. The practical channel rate is synchronous voice communication up to three channels, or simultaneous voice and data communication on one channel. Asynchronous channels support 721 Kbps bi-directional connections and 57.6 Kbps return connections, or symmetric links at 432.6 Kbps.

  FIG. 9 is a diagram illustrating a communication channel changing method of the wireless AV system. When the wireless AV system complies with the IEEE802.11 standard, 14 channels from channel 1 to channel 14 are allocated in the 2.4 GHz band of 2.400 to 2.483 GHz, but the same area is used. When a plurality of channels are set at the same time, the frequency interval between adjacent channels is set to 25 MHz or more. This is because the transmitted / received high-frequency signal has a modulated fixed band, so that when the frequencies of adjacent channels are close to each other, the signals of the respective channels become interference radio waves to each other. Because. Therefore, the number of channels that can be set simultaneously in the same area is limited to a maximum of three channels as shown in channels A, B, and C (channel C is not shown) as shown in FIG. If an attempt is made to construct a wireless LAN system for each house or room in an area where there is a high density of buildings or in a building where rooms are close to each other, a shortage of channels will occur.

  Therefore, in a wireless network, when a transmitter and a receiver are communicating with a specific frequency (communication channel), when the same communication channel is used by another transmitter and receiver pair, the communication channel is used later. It is necessary to change the communication device to a vacant communication channel.

  In the example of FIG. 9, the transmitter A performs packet communication with the receiver A using the channel A. At this time, when the transmitter B intends to perform communication, the transmitter A uses the channel A, and the transmitter B performs packet communication with the receiver B using the channel B other than the channel A. Will be. Here, when the transmitter C further attempts to perform communication, since the transmitter A uses the channel A and the transmitter B uses the channel B, the communication is performed using the channel C other than the channels A and B. Become.

  However, from the viewpoint of the transmitter C, it may not be easily determined whether or not another transmitter (for example, the transmitter A) is performing packet communication. That is, when the stream is not transmitted for some reason in the transmitter A (for example, when the video is stopped by pressing the stop button), the transmitter C determines that the channel A is empty, and When transmitter A starts communicating again, transmitter A has to go looking for a new channel because channel A has been used by transmitter C. It may take about 3 seconds to switch channels because processing such as initialization is included.

  Originally, the stream is interrupted during the channel change. Therefore, in the present embodiment, as described in detail with reference to FIGS. 4 to 7, when the communication state is interrupted, for example, when switching the communication channel, it is determined whether the video has been interrupted or the transceiver has changed the communication channel. , "Connecting", "Searching for a channel", "Signal is hard to reach", "Out of service" and other messages (display message, voice message, or a combination of these) It is possible to prevent the user from feeling uncomfortable.

  Further, in the present embodiment, the time during which communication is interrupted in a certain channel is measured, and if the time during which communication is interrupted is within a predetermined timeout period, control is performed to determine that the channel is in use. This control is performed by the control unit of the transceiver. For example, in the case of the wireless AV system shown in FIGS. 1 to 3, the wireless center microcomputer 37 and / or the TV microcomputer 64 execute the control.

  In the example of FIG. 9, when the transmitter A is performing packet communication with the receiver A using the channel A and the transmitter B intends to perform communication, since the transmitter A is using the channel A, The transmitter B performs packet communication with the receiver B using the channel B other than the channel A. Here, at the time shown in FIG. 9, when the transmitter C further attempts to perform communication, the packet communication of the transmitter A and the packet communication of the transmitter B are interrupted, but both are within the set timeout time. Channel A and channel B are both determined to be in use, and channel A or channel B is not used by transmitter C. As a result, frequent switching of channels can be prevented beforehand, and an optimal communication state can be maintained in the entire network.

  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 TV main body 3 transmits from the SS transmission unit 36 of the wireless center 2. An SS receiving unit 61 that receives the received MPEG2 stream and command transmission data and decodes the received MPEG2 stream and the like, a TV display unit 63 that displays video signals and outputs audio signals, and a TV that controls the entire apparatus. The TV microcomputer 64 includes a microcomputer 64 and a second SS-CPU 84 that detects a communication state between the wireless center 2 and the TV main body 3 in response to a retransmission request based on an electric field strength of a received radio wave and an error rate. Based on the status, video and audio data is interrupted, communication channel is being changed OSD display on the TV display unit 63 each message of the reception sensitivity information including the fact that the connection is being established and the reception sensitivity information including out of the communication range. Therefore, when the communication channel is switched or the radio wave condition is poor, the communication status is interrupted. In addition, an appropriate message indicating the transmission status will be displayed, and the user can determine whether the video has been interrupted, whether the communication terminal has changed the communication channel, or whether the communication condition has deteriorated due to jamming radio waves such as using a microwave oven. Can be easily known, and the user's discomfort can be resolved. For example, since a message such as "Connecting" is displayed by the OSD display even when the video is not displayed, the user can intuitively understand the reason why the video is not displayed and wait until the video is displayed, It is possible to prevent useless channel operation for avoiding a state in which no video is displayed. By avoiding unnecessary channel operations and the like by the user, the time until image display can be further reduced.

  In the present embodiment, as described in (4) Transition from out of service area in FIG. 7, the content of the message is changed according to the communication state, so that the user can know the transition of the communication state. These messages are examples, and any content may be notified at any step. For example, when deterioration or recovery of the communication state can be expected, it is easier to understand if the approximate time until the video is displayed and the image character indicating the time are notified.

  Also, when the reception condition is deteriorating, the user is prompted to take the next action guideline (for example, "Reception condition is getting worse. Please move to a place where radio waves are easy to reach." Please get away from obstacles such as microwave ovens. ") If you make announcements by display / voice, a more friendly system will be achieved.

  In the present embodiment, a message indicating the transmission status of video and audio data and the like is displayed on the TV display unit 63 by OSD to notify the transmission status message of video and audio data and the like. May be notified by voice using a combination of the above, or may be notified in combination. In addition, any display method is not limited to the OSD display.

  Further, in the present embodiment, the time when communication is interrupted is measured, and the communication channel is held until a predetermined set time elapses after the communication is interrupted, so that frequent switching of the channel is prevented. It is possible to maintain an optimal communication state in the entire network.

  Note that the wireless communication device and the wireless AV system of the present invention are not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the spirit 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 an integrated device thereof. For example, in addition to a VTR (Video Tape Recorder), a recording / reproducing device for recording on an HDD or DVD may be used as the AV device. Further, as a device capable of transmitting and receiving data, a device integrated with an information device function represented by a personal computer may be used, and is applicable to all systems. Further, the content of the transmission / reception data may be any.

  Further, in the present embodiment, a TV receiver has been described, but the present invention is not limited to this, and as described above, the present invention can be applied to a tuner and a personal computer, or other AV equipment using the tuner.

  In addition, the types of the processing units and the like and the types and formats of the setting information that constitute the wireless communication device and the wireless AV system are not limited to the above-described embodiments. In particular, it is suitable to be applied to a device conforming to HAVi.

  Further, as the tuners, two broadcasts, a BS tuner and a U / V tuner, are taken as examples, but the types and number of broadcasts such as CS tuners are not limited to these.

  Although the names of the wireless communication device and the wireless AV system are used in the present embodiment, this is for convenience of explanation, and may be a wireless communication device, an AV device, a broadcast station selection device, 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 the program medium can be read by inserting the recording medium into the program reading device. You may. In any case, the stored program may be configured to be accessed and executed by the CPU, or the program may be read in any case, and the read program may be stored in a program storage area (not shown). And the program may be executed. It is assumed that this download program is stored in the main unit 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 disk system of an optical disk such as an MD / DVD, a card system such as an IC card / optical card, or a fixed medium including a semiconductor memory such as a mask ROM, EPROM, EEPROM, or flash ROM. .

  Further, although not shown, when a device capable of connecting to an external communication network is provided, the program is fluidly loaded so that the program is downloaded from the communication network via the communication connection device. Media. When the program is downloaded from the communication network as described above, 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, but may be data.

FIG. 1 is a block diagram illustrating a configuration of a wireless communication device and a wireless AV system according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration of a wireless communication apparatus and a wireless center of a wireless AV system according to the present embodiment. FIG. 2 is a block diagram illustrating a configuration of a TV main body of the wireless communication device and the wireless AV system according to the present embodiment. FIG. 4 is a diagram showing state transitions for describing a communication channel changing method of the wireless communication device and the wireless AV system according to the present embodiment. FIG. 4 is a diagram showing state transitions for describing a communication channel changing method of the wireless communication device and the wireless AV system according to the present embodiment. FIG. 4 is a diagram showing state transitions for describing a communication channel changing method of the wireless communication device and the wireless AV system according to the present embodiment. FIG. 4 is a diagram showing state transitions for describing a communication channel changing method of the wireless communication device and the wireless AV system according to the present embodiment. FIG. 2 is a diagram illustrating transmission and reception of data by a plurality of transceivers A, B, and C of the wireless communication device and the wireless AV system according to the present embodiment. FIG. 3 is a diagram illustrating an example of using communication channels of a plurality of transceivers A, B, and C of the wireless communication device and the wireless AV system according to the present embodiment.

Explanation of reference numerals

1 wireless AV system 2 wireless center unit (wireless center) (wireless communication device, center device)
3 Television main unit (TV main unit) (wireless communication device, display device)
DESCRIPTION OF SYMBOLS 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 18 Car-DC power supply 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)
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 (part of notification means)
64 TV microcomputer (part of notification means)
66 Remote control light receiving section 67 Battery 68 Battery charger microcomputer 81 SS wireless reception engine 82 MPEG2 decoder 83 D / A conversion section 84 Second SS-CPU (communication state detecting means)

Claims (14)

Communication means for transmitting and receiving control commands including video and audio data, or communication channel change information,
Communication state detection means for detecting a communication state;
And a notifying unit for notifying at least the transmission state of the video and audio data based on the communication state detected by the communication state detecting unit.   2. The wireless communication apparatus according to claim 1, further comprising measuring a time when the communication is interrupted, and holding the communication channel until a predetermined time elapses after the communication is interrupted.   The wireless communication device according to claim 1, wherein the communication unit transmits the video and audio data or the control command by an SS wireless system.   4. The wireless communication apparatus according to claim 1, wherein the communication unit transmits the video and audio data using an MPEG stream conforming to an MPEG2 encoding scheme. 5.   The wireless communication device according to claim 1, wherein the communication unit is a low-power short-range two-way wireless communication.   The wireless communication device according to claim 1, wherein the communication unit is one of Bluetooth, UWB, and a wireless LAN.   The wireless communication device according to any one of claims 1 to 6, wherein the communication state detection means detects a communication state based on an electric field strength of a received radio wave, an error rate, or the number of retransmission requests based on the error rate. Communication device.   The wireless communication device according to claim 1, wherein the communication state detection unit detects a communication state between wireless communication devices with which a communication link has been established.   The notifying unit notifies at least one or more of the interruption of the video and audio data, the change of the communication channel, the connection, and the reception sensitivity information including out of the communication range. The wireless communication device according to claim 1, wherein:   The wireless communication device according to claim 1, wherein the notification unit is configured to display a message by a display unit or generate a message by a voice output unit. A wireless AV system for connecting a plurality of wireless communication devices through a wireless network,
The wireless AV system according to claim 1, wherein the wireless communication device is the wireless communication device according to claim 1.   The wireless communication device according to claim 11, wherein the wireless communication device is a television receiver including a display device, a center device having a tuner for broadcast reception, and transmitting video and audio data to the display device. Wireless AV system.   In a plurality of wireless communication devices constituting a wireless network, video and audio data, or send and receive a control command including communication channel change information, to detect the communication state, based on the detected communication state, at least the video and A program for causing a computer to execute a control process of notifying a transmission status of audio data.   In a plurality of wireless communication devices constituting a wireless network, video and audio data, or send and receive a control command including communication channel change information, to detect the communication state, based on the detected communication state, at least the video and A computer-readable recording medium having recorded thereon a program for causing a computer to execute a control process of notifying a transmission status of audio data.

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