JP2010034831A - Wireless communication device and central control wireless communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication system in which a wireless communication device transmitting data can flexibly vary a data compression rate and/or data rate used for data coding. <P>SOLUTION: A wireless communication device transmitting data transmits a beacon slot complying with multiband orthogonal frequency division multiplexing (MB-OFDM) system predetermined by WiMedia Aliance to a transmission side wireless communication device encoding the data, the slot including data compression rate information and/or data rate information. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wireless communication apparatus, and more particularly to a wireless communication apparatus using a WiMedia Alliance multiband orthogonal frequency division multiplexing (MB-OFDM) system.

  A wireless communication system in which a wireless communication device that transmits video and audio data and a wireless communication device that receives the data is arranged at a short distance of about 10 meters is mounted on a moving means such as a vehicle, a ship, and an aircraft. Or it can be installed and used indoors such as at home or office.

  As the above communication system, a wireless communication system suitable for video and audio data communication at a short distance of about 10 meters is an ultra wideband wireless (UWB) capable of high-speed transmission at a short distance. In particular, there is a multiband orthogonal frequency division multiplexing (MB-OFDM) system defined by the WiMedia Alliance.

  As a conventional example in a wireless communication system of the multi-band orthogonal frequency division multiplexing (MB-OFDM) scheme of WiMedia Alliance, as a management method of beacon information for controlling communication between wireless communication devices, a beacon position transmitted by itself is used. There is a system in which communication between wireless communication devices is controlled by managing beacon information from other wireless communication devices on the basis of (beacon slot). (See Patent Document 1)

Japanese Patent Laid-Open No. 2007-243749 (Summary FIG. 15)

  In general, in a communication system that wirelessly communicates large data such as video and audio, data is compressed by data encoding using a codec or the like. When using this wireless communication system in a vehicle, such as when the communication environment changes due to disturbances, etc., or when the required data rate changes, data encoding is performed in accordance with those changes. It is necessary to flexibly change the data compression rate and / or data rate used for the data.

  The present invention has been made in view of the above circumstances, and a wireless communication system in which a wireless communication apparatus that transmits data can flexibly change a data compression rate and / or data rate used for data encoding. The purpose is to provide.

  In the wireless communication apparatus according to the present invention, the data compression rate information and / or the beacon slot of the multiband orthogonal frequency division multiplexing (MB-OFDM) system defined by the WiMedia Alliance is transmitted to the transmitting wireless communication apparatus that performs data encoding. Added data rate information.

  According to the wireless communication apparatus of the present invention, the data compression rate and / or data rate used for data encoding can be flexibly changed.

Hereinafter, the present invention will be described in detail based on embodiments.
Embodiment 1 FIG.
FIG. 1 is a diagram illustrating an in-vehicle multimedia wireless communication system according to the present embodiment. In the figure, dotted arrows indicate video / audio data transmission paths between wireless communication apparatuses in the present embodiment.
1, the in-vehicle multimedia wireless communication system includes a central control unit 1, a rear seat entertainment (hereinafter referred to as RSE) 2, and a rear camera (hereinafter referred to as CMR) 3 as wireless communication devices in the present embodiment. And monitors 4-8. The central control unit 1, RSE2, CMR3, and monitors 4 to 8 form a beacon group using the Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) method of UWB (Ultra Wide Band) Wimedia Alliance. It has a function of wirelessly communicating with each other within a group. Details of the beacon group will be described later. In the present embodiment, these wireless communication devices 1, 2, 4 to 8 transmit data including the data compression rate information and / or data rate information in the beacon slot, thereby transmitting data to the wireless communication device. A data compression rate and / or data rate used for encoding the transmission data is designated for the transmitting side wireless communication apparatuses 1 to 3 to be transmitted.

  The central control unit 1 has a video / audio source such as a DVD or a CD, encodes the video / audio data, and wirelessly transmits them to the RSE 2 and the front seat monitors 4 to 6. Further, the central control unit 1 has a function of receiving a captured image in the CMR 3 wirelessly transmitted from the CMR 3 and displaying it on an attached display device. The RSE 2 relays the video / audio data wirelessly transmitted from the central control unit 1 and wirelessly transmits the encoded video / audio data to the rear seat monitors 7 and 8, and the RSE 2 itself is also a DVD or CD. The video / audio source is encoded, and the video / audio data is encoded and wirelessly transmitted to the rear seat monitors 7 and 8. The central control unit 1 and the RSE 2 each have an interface that can be operated by a front seat occupant and a rear seat occupant, whereby each occupant can arbitrarily select a favorite content. The central control unit 1 and the RSE 2 communicate with each other to wirelessly transmit a control signal corresponding to the occupant's operation and video / audio data corresponding to the control signal.

  FIG. 2 is a block diagram showing a configuration of the monitor 4 shown in FIG. The monitors 5 to 8 have the same configuration as that shown in FIG. In FIG. 2, the monitor 4 includes an antenna 200, a receiving unit 201, a decoding unit 202, a video / audio output unit 203, an encoded information generation unit 204, a communication environment index value calculation unit 210, and a transmission unit 205. The UWB device 206 is configured by the receiving unit 201 and the transmitting unit 205, and this UWB device 206 can perform transmission and reception corresponding to the UWB WiMedia Alliance multiband orthogonal frequency division multiplexing (MB-OFDM) system, which will be described later. It is. The MB-OFDM PHY and MAC structures are defined in the standard ECMA-368 “High Rate Ultra Wideband PHY and MAC Standard”, for example. The antenna 200 is an antenna that can transmit and receive at a frequency approved for use from 3 GHz to 10 GHz band suitable for the UWB communication. The video / audio output unit 203 is connected to a display device (not shown), a speaker, and the like.

  FIG. 3 is a block diagram showing a configuration of the central control unit 1 shown in FIG. In FIG. 3, the central control unit 1 includes an antenna 300, a receiving unit 301, a decoding unit 302, a video / audio input / output unit 303, an encoded information generating unit 304, a communication environment index value calculating unit 310, an encoding unit 305, A control unit 306 and a transmission unit 308 are included. Similarly to the UWB device 206 of the monitor 4, the UWB device 309 including the reception unit 301 and the transmission unit 308 can perform transmission and reception corresponding to the UWB WiMedia Alliance multiband orthogonal frequency division multiplexing (MB-OFDM) system. is there. The video / audio input / output unit 303 is connected to a display device (not shown), a speaker, and the like, and has a video / audio source such as a DVD or a CD. The central control unit 1, monitors 4 to 8, RSE2, etc. The video / audio data instructed by the user via a user operation unit (not shown) provided in is output to the encoding unit 305. The above is the configuration of the central control unit 1. The RSE 2 has the same configuration as the central control unit 1.

  FIG. 4 is a block diagram showing the configuration of the CMR 3 shown in FIG. In the figure, the CMR 3 includes an antenna 400, a reception unit 401, a camera unit 403, an encoding unit 405, a control unit 406, and a transmission unit 408. The UWB device 409 including the receiving unit 401 and the transmitting unit 408 can also perform transmission and reception corresponding to the UWB WiMedia Alliance multiband orthogonal frequency division multiplexing (MB-OFDM) system. Video data behind the vehicle imaged by the camera unit 403 is encoded by the encoding unit 405 and transmitted to the central control unit 1 via the transmission unit 408 and the antenna 400.

  Next, transmission / reception of the WiMedia Alliance multiband orthogonal frequency division multiplexing (MB-OFDM) system performed by the UWB devices 206, 309, and 409 shown in FIGS. In the wireless communication system, a superframe in units of 65.536 msec shown in FIG. 5 is defined. One super frame is subdivided into 256 MASs (Media Access Slots), and 1 MAS has a period of 256 usec. Of the 256 MAS slots, a slot in the first half period defined as a beacon period is used as a timing at which each wireless communication device transmits a beacon. A beacon slot that is an allocation period for transmitting the beacon is defined as an 85 usec period, and 3 beacon slots are allocated to 1 MAS. Also, the beacon period is set for a period of a required length depending on the number of UWB wireless communication devices existing in the surroundings, and can be set up to a maximum of 96 slots. (In other words, up to 32 MAS can be used as a beacon slot.) A period other than the beacon period in the superframe is a data transmission / reception enabled period, and the MAS during that period is used for communication of data such as video / audio. used.

  There are two types of data communication methods in the MB-OFDM method: a DRP (Distributed Reservation Protocol) transfer method and a PCA (Prioritized Contention Access) transfer method. In the DRP transfer method, communication is performed by negotiating between wireless communication devices in a beacon period and reserving a MAS in a data transmission / reception enabled period in advance, and communicating data using the reserved MAS when the data transmission / reception enabled period starts. It is a method. On the other hand, the PCA transfer method is a communication method in which data is communicated using a vacant MAS in which a data transmission / reception available period is not reserved.

  Further, as shown in FIG. 6, the MB-OFDM PHY frame structure includes a fixed-length PLCP (Physical Layer Convergence Protocol) preamble, a PLCP header, and a variable-length PSDU (PHY Service Data Unit). When beacon frame information is written in Frame Type data of the MAC header in the PLCP header, Frame Payload becomes Beacon Frame (Beacon Payload). FIG. 6 shows a configuration example of Beacon Parameter, BPO (Beacon Period Occupancy) _IE (Information Elements), and PCA Availability_IE as an example of Beacon Payload. If data frame information is written in Frame Type data of the MAC header in the PLCP header, Frame Payload becomes Data Payload.

  For example, the beacon payload includes the unique information of the device that transmitted the beacon, the beacon slot number to be used, the usage information of the beacon slot, and the usage information of the PCA, and these information is broadcast to the periphery by the beacon. In the example of FIG. 6, Beacon Parameter, BPO_IE (Beacon Period Occupancy Information Elements) and PCA Availability_IE are shown as examples of the beacon payload. It is possible to do.

  Each UWB device 206, 309, 409 as shown in FIGS. 2 to 4 uses one or a plurality of beacon slots unique to one device, and various parameters are set for the surrounding UWB devices. By broadcasting, control information is notified to each other. The UWB devices 206, 309, and 409 are synchronized with each other at the same beacon start time in the superframe. A group in which a plurality of peripheral UWB devices are synchronously established in the same superframe period is called a beacon group.

  FIG. 9 shows an example in which a plurality of UWB devices 206a, 206b, and 309 construct a beacon group. Here, the UWB devices 206 of the monitors 5 and 6 are denoted by 206a and 206b, respectively, and an example in which these UWB devices 206a and 206b and the UWB device 309 of the central control unit 1 configure the same beacon group is shown. Note that the UWB devices of the monitors 4, 7, and 8 arranged in the same vehicle and the UWB devices of RSE2 and CMR3 described later also constitute the same beacon group, but the illustration is omitted here. The communicable area by UWB is a short range because the RF frequency used by UWB is the GHZ band, and is suitable for covering only the same vehicle. The communicable range of the UWB device 206a is 81, the communicable range of the UWB device 206b is 82, the communicable range of the UWB device 309 is 83, and the communicable range of the UWB device 441 located outside the same vehicle is, for example, 84, the UWB devices 206a, 206b, and 309 are within the communication range of each other, can transmit and receive beacons, and one beacon group that is synchronized and established in the same superframe is constructed. However, since none of the UWB devices 206a, 206b, and 309 are included in the communicable range of the UWB device 441 outside the vehicle, the UWB device 441 cannot enter the same beacon group.

  The UWB devices 206a, 206b, 309, etc. that make up one beacon group receive each other's beacon frames, and synchronize with the same superframe to send MAS specified by DRP or MAS not specified. Used to transmit / receive video / audio data using DRP or PCA transfer method.

  The DRP transfer method is suitable for the case where the data to be transmitted is streaming such as an image and has a high data rate, and the required MAS for the data rate of the video / audio data transmitted by the central control unit 1 is determined by DRP. By securing in advance, it is possible to receive image data at a high data rate without failure on the monitor 4-8 side.

  However, conventionally, the data rate output from each UWB device is UWB communication of high-rate image data as it is without being aware of the communication environment. For this reason, when there are a plurality of UWB devices in a beacon group and there are a plurality of communications between the devices, there is a case where all communications cannot be processed at a data rate that can be transmitted in a communication environment within the beacon group.

For example, the UWB devices 206a, 20 which constitute the beacon group in FIG.
6b and 309, when MAS = 200 required for data transmission from the UWB device 309 to the UWB device 206a and MAS = 100 required for data transmission from the UWB device 309 to the UWB device 206b, the beacon group The total number of MASs required for all of the communication is 300, and the MAS cannot be set in the 256 MAS in the superframe, and the MAS cannot be set, or one of the communication is likely to fail.

  In this way, when there are a plurality of communications between UWB devices in a beacon group, if video / audio data having a high data rate is communicated at the same data rate, the amount of communication is often excessive. Therefore, in the present embodiment, when the transmitting-side wireless communication apparatus transmits data such as video / audio using the MB-OFDM method, the data is converted into a predetermined data compression rate and data rate. To send. In particular, the transmitting-side wireless communication device receives data compression rate information (ie, data compression rate information) and / or data rate information (ie, data rate information) from other wireless communication devices in the same beacon group. Then, the data compression rate and data rate of the data to be transmitted are changed based on the data compression rate information and / or data rate information. The reception-side wireless communication device includes the data compression rate information and the data rate information in a beacon slot of the MB-OFDM scheme and transmits the information to the transmission-side wireless communication device.

  For example, in order to compress data to be transmitted and received, a codec such as MPEG is used as an algorithm for encoding / decoding data. In the MPEG codec, video data is differentially processed in units of frames using a frame memory or the like. As a result, although the amount of delay increases due to the processing time in units of frames, the compression rate can be increased and compressed data at a low rate can be created. Also, by reducing or eliminating the number of frames used for differential processing, it is possible to produce compressed data with a relatively high data rate with low delay, although the compression rate is reduced.

  Now, it is assumed that a plurality of wireless communication devices of the wireless communication system of FIG. 1 establish the same beacon group and perform communication. The operation will be described below by taking data communication between the monitor 4 shown in FIG. 2 and the central control unit 1 shown in FIG. 3 as an example.

  The video / audio input / output unit 303 of the central control unit 1 that is a transmitting side wireless communication device outputs encoded data such as MPEG2 read from, for example, a DVD to the encoding unit 305. The control unit 306 controls the encoding in the encoding unit 305 based on the data compression rate information and / or the data rate information in the beacon slot received by the receiving unit 301, and thereby the code output from the encoding unit 305 Control the data compression rate and data rate of digitized data. The encoding performed by the encoding unit 305 may be, for example, converting input MPEG2 encoded data into data of different data rates in the same MPEG2 system, or converting MPEG2 encoded data to MPEG4 or the like. May be converted into coded data of a different codec type. The encoded data output from the encoding unit 305 is transmitted from the transmission unit 308 using the MB-OFDM MAS described above.

  The encoded data transmitted from the central control unit 1 is received by the reception unit 201 of the monitor 4 that is a reception-side wireless communication device, and is output to the decoding unit 202. If the encoded data is compressed data obtained by compressing an image such as MPEG, the information necessary for decoding the data is written in the header information in the encoded data. The unit 202 does not need to receive special data separately in order to decrypt the data.

  Here, the number of MASs already secured in the superframe established in the beacon group is MH, and the number of MASs not secured is MF. When performing communication, if the number of MASs required for the communication is MD, the control unit 306 specifies a data rate and a data compression rate that satisfy the relationship MD <MF to the encoding unit 305. The monitor 4 which is the receiving side wireless communication apparatus transmits information necessary for calculating the MD in the beacon slot to the transmitting side wireless communication apparatus as data compression rate information or data rate information. Alternatively, the central control which is the transmission side wireless communication apparatus includes calculating the MD in the reception side wireless communication apparatus and including the data compression rate or the data rate itself satisfying MD <MF in the beacon slot as the data compression rate information and the data rate information. Send to the control unit.

  Next, while the central control unit 1 which is the transmitting side wireless communication device is transmitting data to the monitor 4 which is the receiving side wireless communication device, the data compression rate and data rate required for the data in the monitor 4 The case where changes will be described. Such a request for changing the data compression rate or data rate is caused by a change in image quality, display size, communication environment, or the like assumed by the receiving-side wireless communication apparatus.

  For example, it is assumed that the communication environment between the central control unit 1 and the monitor 4 has deteriorated. At this time, the monitor 4 selects a new data compression rate and / or data rate required for the central control unit 1 and informs the central control unit 1 of this, and this is performed as follows. In the monitor 4 shown in FIG. 2, the communication environment index value calculation unit 210 calculates a value that is an index of the communication environment based on the error rate of the communication and inputs the value to the encoded information generation unit 204. Next, the encoding information generation unit 204 selects the data compression rate and / or data rate based on the communication environment index value input from the communication environment index value calculation unit 210, and the data compression rate information and / or Alternatively, data rate information is generated. The data compression rate information and / or data rate information is transmitted from the antenna 200 in the beacon slot in the beacon group in the UWB device 206.

  The central control unit 1 shown in FIG. 3 receives the data compression rate information and / or data rate information transmitted by being included in the beacon slot from the antenna 300, extracts it by the UWB device 309, and requests the data requested by the monitor 4 The compression rate and / or data rate can be known. Next, the control unit 306 sets the data compression rate and / or data rate in the encoding unit 305 based on the received data compression rate information and / or data rate information. The encoding unit 305 encodes the data output from the video / audio input / output unit 303 at the set data compression rate and / or data rate. The encoded data is transmitted from the antenna 300 to the monitor 4 via the UWB device 309.

  Next, the monitor 4 receives the encoded data sent from the central control unit 1 from the antenna 200. The encoded data is sent to the decoding unit 202 via the UWB device 206, where it is decoded. The decoded data is output from the video / audio output unit 203, and the video / audio included in the data is reproduced from a display device (not shown) and a speaker.

  Although the case where the communication environment deteriorates is assumed here, the situation where the data compression rate / data rate should be changed is not limited to this. It is also possible to change the image display size or image / audio quality, or when the communication is congested and there are fewer free MASs. Therefore, the encoding information generation unit 204 changes the information in consideration of the necessary image display size, image / audio quality, MAS reservation status or usage status information sent in the beacon slot of another UWB device. The previous data compression rate and / or data rate may be selected.

  Next, the position where the data compression rate information and / or the data rate information are included in the beacon slot when the data compression rate information and / or the data rate information is transmitted in the beacon slot will be described. FIG. 7 is a diagram showing types of information elements defined in the WiMedia Alliance multiband orthogonal frequency division multiplexing (MB-OFDM) system. FIG. 7 is a diagram showing the ID numbers of the information elements and their contents, and FIG. 8 is a diagram showing the structure of each information element. As a position where the data compression rate information and / or data rate information is included in the beacon slot, for example, any one of ElementID252 to 255 in the Information Element arranged in the beacon payload shown in FIG. 7 or FIG. The IE-specific field is a candidate. As another candidate, you may include in the Device control field arrange | positioned in a beacon payload.

  Here, the operation has been described by taking the data communication between the central control unit 1 and the monitor 4 as an example, but the data communication between the central control unit 1 and the RSE2, CMR3, and the front seat monitors 4 to 6, the RSE2 and the rear seat. The operation of data communication with the monitors 7 and 8 is the same.

  As described above, in the wireless communication apparatus according to the present embodiment, in the WiMedia Alliance multiband orthogonal frequency division multiplexing (MB-OFDM) system, information regarding the data compression rate / data rate is transmitted by being included in the beacon slot. Therefore, even if the required data rate changes, such as when the communication environment deteriorates due to disturbances, etc., the data compression rate and / or data rate is flexibly changed between each UWB communication accordingly. It becomes possible. As a result, data communication between the wireless communication devices can be made difficult to fail.

Embodiment 2. FIG.
In the present embodiment, there is a MAS that can be used as PCA transfer after the generation of data compression rate information and / or data rate information to be transmitted to the transmitting-side wireless communication apparatus and before the transmission timing of the next beacon slot. The data compression rate information and / or data rate information is transmitted by the PCA transfer method using the MAS instead of the beacon slot transmission.

  That is, in the first embodiment, the transmission unit 205 of the monitors 4 to 8 shown in FIG. 2 and the transmission unit 308 of the central control unit 1 (or RSE 2) shown in FIG. The data compression rate information and / or data rate information generated in step 1 is transmitted using a beacon slot. However, in the present embodiment, the transmission unit 205 or the transmission unit 308 uses the transmission timing of the beacon slot. If there is a MAS that can be used as PCA transfer before, the data compression rate information and / or data rate information is transmitted by PCA transfer using the MAS.

  In the first embodiment, the receiving unit 301 of the central control unit 1 (or RSE 2) shown in FIG. 3 and the receiving unit 401 of the CMR 3 shown in FIG. 4 store the data compression rate information and / or data rate information. In this embodiment, when data compression rate information and / or data rate information is transmitted by PCA transfer, the data is transferred from the beacon slot only to the control units 306 and 406. Data compression rate information and / or data rate information is received and output to the control units 306 and 406. The other points are the same as in the first embodiment. When there is no MAS that can be used for such PCA transfer, the data compression rate information and / or the data rate information is transmitted in a beacon slot.

  FIG. 10 is a diagram illustrating a PCA transfer method used for transmission of data compression rate information and / or data rate information in the present embodiment. Here, MASs 32 to 36 and 40 to 42 during a data transmission / reception enabled period are reserved for the DRP transfer method by beacons transmitted from each wireless communication device using a beacon period. For example, communication from the central control unit 1 to the monitor 4 is reserved in the MASs 32 to 36, and communication from the RSE 2 to the central control unit 1 is reserved in the MASs 40 to 42. On the other hand, the MAS indicated as PCA OK in the figure is a MAS that is not reserved and can be used for PCA transfer.

  In Embodiment 1 described above, the data compression rate information and data rate information from the reception-side wireless communication device are transmitted using the beacon slot in the superframe, so the compression rate and data rate in the transmission-side wireless communication device are This change is performed in units of superframe = 65.536 msec. Accordingly, the communication bandwidth (for example, the bandwidth of the DRP period of the MAS 32 to 36) secured between the devices at an arbitrary timing during the data transmission / reception possible period (minimum 65.536-8.192 = 57.344 msec). Even if you try to change the data compression rate and data rate to the maximum (for example, the same compression method for image data, generally the higher the data rate, the higher the image quality. It is better to change to higher data), and since the data compression rate and data rate can only be changed in units of superframes, it is assumed that the changes in each device will be delayed in response to those changes. Is done.

  On the other hand, in the present embodiment, there is an MAS that can be used as PCA transfer after the generation of data compression rate information and / or data rate information to be transmitted to the transmitting-side wireless communication device and before the beacon slot transmission timing. In this case, in order to transmit the data compression rate information and / or data rate information by the PCA transfer method using the MAS instead of the transmission by the beacon slot, the data compression rate information and the data rate information are quickly transmitted. Can be sent to. Also, when all MASs are reserved for DPR transfer and there is no MAS that can be used for PCA transfer, or when the beacon slot transmission timing arrives earlier than MAS that can be used for PCA transfer, the PCA transfer method Instead, by transmitting the data compression rate information and data rate information using the same beacon slot as in the first embodiment, the present invention can be applied to cases where there is no or no MAS available for PCA transfer.

  In other words, in the WiMedia Alliance multiband orthogonal frequency division multiplexing (MB-OFDM) system, communication by the PCA transfer system can be performed between any wireless communication apparatuses other than the MAS secured as the DRP. A non-reserved MAS, for example, a MAS in which “PCA OK” such as MAS 30 and 31 and MAS 37 to 39 in FIG. 10 is entered is a MAS that can perform communication by a PCA transfer method between arbitrary wireless communication apparatuses. Now, assume that the data rate of data received by a certain wireless communication device in the beacon group is to be changed. At this time, in this embodiment, if there is a MAS that can be used in communication by the PCA transfer method, the wireless communication device adds data compression rate information and / or data rate information to communication data by the PCA transfer method. Thereby, it is possible to notify other wireless communication devices in the beacon group as soon as possible of the request for changing the data compression rate and / or the data rate even in the data transmission / reception possible period other than the beacon period.

  Here, it is assumed that a plurality of wireless communication devices of the wireless communication system shown in FIG. 1 establish the same beacon group and perform communication. The operation will be described below by taking data communication between the monitor 4 shown in FIG. 2 and the central control unit 1 shown in FIG. 3 as an example.

It is assumed that the communication environment of the communication has deteriorated while the central control unit 1 that is the transmission side wireless communication device is transmitting data to the monitor 4 that is the reception side wireless communication device. At this time, the monitor 4 selects a new data compression rate and / or data rate required for the central control unit 1 and informs the central control unit 1 of this, and this is performed as follows. In the monitor 4, the communication environment index value calculation unit 210 calculates a value serving as an index of the communication environment based on the error rate of the communication and inputs the value to the encoded information generation unit 204. Next, the encoding information generation unit 204 selects the data compression rate and / or data rate based on the communication environment index value input from the communication environment index value calculation unit 210, and the data compression rate information and / or Alternatively, data rate information is generated. The data compression rate information and / or data rate information is included in the communication data of the beacon period or PCA transfer method in the UWB device 206 and transmitted from the antenna 200.

  The central control unit 1 receives the data compression rate information and / or data rate information transmitted in the beacon slot or PCM transfer type communication data from the antenna 300, extracts it by the UWB device 309, and requests the monitor 4 It is possible to know the data compression rate and / or data rate to be performed. Next, the control unit 306 sets the encoding unit 305 based on the received data compression rate information and / or data rate information. The encoding unit 305 encodes the data output from the video / audio input / output unit 303 at a set data compression rate and / or data rate. The encoded data is transmitted from the antenna 300 to the monitor 4 via the UWB device 309.

  Next, the monitor 4 receives the encoded data sent from the central control unit 1 from the antenna 200. The encoded data is sent to the decoding unit 202 via the UWB device 206, where it is decoded. The decoded data is output from the video / audio output unit 203, and the video / audio included in the data is reproduced from a display device (not shown) and a speaker.

  In this embodiment, as a method for transmitting data compression rate information and / or data rate information using a beacon slot or PCM transfer method in this way, MAS that can be used as PCA transfer rather than beacon slot transmission timing. If the transmission timing of the beacon slot arrives earlier than the MAS that can be used for PCA transfer, the information is transmitted using the beacon slot. By transmitting, it is possible to transmit such information quickly.

  If there is a MAS that can be used for PCA transfer, the data compression rate information and / or data rate information is always transmitted using only PCA transfer without using any beacon slot. Control for transmission may be simplified.

  Alternatively, after transmitting data compression rate information and / or data rate information by PCA transfer, the same information as that information is transmitted again using the transmission timing of the beacon slot, so that only the information included in the beacon slot is transmitted. The present invention can also be applied to a case where inexpensive wireless communication devices that can receive signals and do not have the function of receiving the information by PCA transfer are mixed in the same beacon group.

  Here, the operation has been described by taking the data communication between the central control unit 1 and the monitor 4 as an example, but the data communication between the central control unit 1 and the RSE2, CMR3, and the front seat monitors 4 to 6, the RSE2 The operation of data communication with the rear seat monitors 7 and 8 is the same.

  As described above, according to the wireless communication device in the present embodiment, it is possible to transmit / receive a request to change the data compression rate and / or data rate from each wireless communication device without waiting for the beacon period of the superframe. Therefore, the response of changing the data compression rate and / or data rate is improved.

Embodiment 3 FIG.
In the present embodiment, one wireless communication device in the beacon group receives data compression rate information and / or data rate information from a plurality of wireless communication devices in the beacon group from the beacon slot, and these are received. Based on the information, the MAS assigned to the communication of each wireless communication device is determined. The determined MAS arrangement is notified to each wireless communication device from the one wireless communication device using the subsequent beacon slot.

The configuration of the in-vehicle multimedia wireless communication system in the present embodiment is the same as that in the first embodiment, as shown in FIG. FIG. 11 is a diagram showing the configuration of the central control unit 1 according to the present embodiment. The difference from the central control unit 1 according to the first embodiment shown in FIG. 3 is that the central control unit 1 includes a determining unit 311. Is a point. The configurations of the monitors 4 to 8, RSE2, and CMR3, which are other wireless communication apparatuses, are the same as those in the first embodiment, and are as shown in FIGS. 2, 3, and 4, respectively.

  In FIG. 1, each wireless communication device is arranged in an area where one beacon group can be constructed. Here, for comparison with the present embodiment, a method will be described in which necessary MAS is reserved after receiving MAS reservation information in units of superframes, and data communication is performed using the DRP transfer method. Now, assume that a plurality of wireless communication devices form a beacon group. The MAS reservation for the DRP transfer method is performed by negotiating the MAS reservation request and the response process with respect to the MAS reservation between the wireless communication apparatuses constituting any communication. The reservation information is notified to other wireless communication devices by beacons. Thereafter, the same processing is performed between the wireless communication apparatuses that perform other communications that have not yet been reserved, and the number of MAS necessary for communication by the DRP transfer method is secured for the free MAS, and the communication bandwidth is increased. Secure.

  For example, in FIG. 1, after the beacon group is established, in order to perform communication between the central control unit 1 and the monitor 4, the MAS quantity necessary for communication by the DRP transfer method is secured, and the central control unit 1 and the monitor The reservation information is transmitted to other devices in the beacon slot after negotiation between the four. Thereafter, the MAS quantity necessary for DRP transfer is secured from the free MAS for communication between the CMR 3 which is one of the other communications and the central control unit 1. As described above, it is necessary to reserve the MAS in the same procedure for communication between all the wireless communication apparatuses scheduled to perform communication within the beacon group. When constructing a plurality of communications having different transmission devices (central control unit 1, RSE2, CMR3 in FIG. 1) in the beacon group, this method requires MAS reservation to be performed in order for each communication, and the beacon slot In order to establish all of the communication, a considerable time of several units is generally required for each superframe.

  Therefore, in this embodiment, in order to facilitate all communication in the beacon group, one wireless communication device in the beacon group manages communication between the wireless communication devices in an integrated manner, Determine allocation of MAS to each communication. Hereinafter, the wireless communication apparatus according to the present embodiment will be described.

In the present invention, data compression rate information and / or data rate information requested from all devices in the beacon group is multicast when the beacon group is established or immediately thereafter. In general, among devices in a vehicle, there is a device serving as the center of a network having a function of controlling each device, and a central control unit having a video / audio source such as a DVD often has the function. . In the present embodiment, the central control unit 1 serving as the center of such a network receives data compression rate information and / or data rate information transmitted from each device when a beacon group is established, and receives them. Based on this, a determination unit 311 for determining the MAS arrangement necessary for communication by the DRP transfer method between the wireless communication devices in the beacon group is provided.

  Next, the operation will be described. In FIG. 11, the central control unit 1 receives data compression rate information and / or data rate information transmitted from other wireless communication devices in the beacon group included in the beacon slot from the antenna 300, and transmits the UWB device. In step 309, data compression rate information and / or data rate information required by a plurality or all of the wireless communication devices in the beacon group are acquired. Next, the determination part 311 determines MAS arrangement | positioning of each communication in a beacon group based on those received information. The determined MAS arrangement is included in the beacon slot via the UWB device 309 and transmitted from the antenna 300 to the RSE 2 and the CMR 3.

  The RSE 2 and the CMR 3 that have received the determined MAS arrangement perform data transmission according to the DRP transfer method accordingly. When the central control unit 1 transmits data, data transmission is performed by the DRP transfer method according to the MAS arrangement determined by the determination unit 311 of the own apparatus.

  The central control unit 1 preferably uses the rearmost beacon slot among the beacon slots used by each wireless communication device of the beacon group in the beacon period of each superframe. The information of the beacon slot is transmitted to each wireless communication device in the beacon group including the determined MAS arrangement.

  As described above, in the wireless communication device in the present embodiment, one wireless communication device in the beacon group receives data compression rate and data rate information requested by each wireless communication device in the beacon group, Since the MAS arrangement determined based on this is included in the beacon period and transmitted, communication between each wireless communication device can be quickly established. In particular, the determined MAS arrangement is transmitted in the beacon period of each superframe by including it in the rearmost beacon slot among the beacon slots used by each wireless communication device of the beacon group. Communication between devices can be established more quickly.

Embodiment 4 FIG.
In the present embodiment, the DRP-based MAS is prioritized for communication in which the central control unit requires low delay by including information on the delay amount allowed by each wireless communication device in the beacon from each wireless communication device. Allow placement.

  FIG. 12 is a diagram illustrating a difference between the case of communication I having a large allowable delay amount and the case of communication having a small amount Ia in communication within a beacon group according to the present embodiment. In the case of the communication I having a large allowable delay amount, for example, 6 MASs can be arranged together. In this case, since data for 6 MAS is temporarily buffered, data communication is delayed by the amount of data to be buffered. On the other hand, in order to reduce the buffering amount, the data is not arranged in a lump, but the transmission is divided into several parts, thereby enabling communication with a small delay amount. The communication Ia when the allowable delay amount is small takes a method of transmitting the same data amount as that of the communication I by dividing it into several as an example of a method of communicating with a low delay. In communication I, 6 MASs were collectively communicated, but by dividing the communication into 3 times at regular intervals every 2 MASs, the delay amount can be reduced to 1/3 with respect to the delay amount at the time of 6 MAS. Here, when the amount of delay allowed by communication II, which is communication between different devices, is large, by using any MAS other than the DRP MAS arranged in communication Ia, Communication can be optimized.

  11, 13, 14, and 15 are diagrams showing the configurations of the central control unit 1, the monitors 4 to 8, the RSE2, and the CMR3 in the present embodiment, respectively. The basic configuration of the in-vehicle multimedia wireless communication system in the present embodiment is the same as that in the third embodiment. The difference from the third embodiment is that the RSE 2, the monitors 4 to 8, and the CMR 3 output the allowable delay amount of communication involving the own device from the allowable delay amount calculation units 213, 313, and 413, and the output allowable delays. The amount is included in the beacon slot and transmitted from the transmission units 205, 308, and 408, and the determination unit 311 of the central control unit 1 determines the MAS arrangement based on the information on the allowable delay amount transmitted. is there.

  Next, the operation of the central control unit 1 shown in FIG. 11 will be described. The central control unit 1 receives from the antenna 300 the allowable delay amount transmitted from other wireless communication devices in the beacon group included in the beacon slot, and takes out the reception unit 301. The determination unit 311 determines communication that requires low delay based on the allowable delay amount of each of the extracted devices, and preferentially arranges MAS for communication that is determined to require low delay. . For example, for communication determined to require low delay, as shown in communication Ia in FIG. 12, a DRP MAS is distributed so that MASs for the communication are distributed in one superframe. Deploy. The determined MAS arrangement is included in the beacon slot via the transmission unit 308, and transmitted from the antenna 300 to the RSE2 and CMR3.

  The RSE 2 and the CMR 3 that have received the determined MAS arrangement perform data transmission according to the DRP transfer method accordingly. Also, when the central control unit 1 transmits data, data transmission is performed by the DRP transfer method according to the MAS arrangement determined by the determination unit 311 of the own apparatus.

  About the position to include the delay amount allowed in the beacon slot, IE-specific field of any of ElementID 252 to 255 in the Information Element arranged in the beacon payload, or Device control arranged in the beacon payload Send it in the field.

  As described above, the beacon signal includes information on the delay amount allowed by each wireless communication device, and the MRP arrangement of the DRP transfer method is arranged with a low delay priority, so a low delay is required in the beacon group. Even when there are a plurality of communications including data communications to be performed, MAS reservation for communications by the DRP transfer method can be optimized.

Embodiment 5 FIG.
Next, a communication environment index value such as RSSI (ReceiveSignalStrengthIndicator) or LQI (LinkQualityIndicator) calculated by the receiving side device in communication between each wireless communication device is used as a WiMedia Alliance multiband orthogonal frequency division multiplexing (MB-OFDM) type beacon. Embodiment 5 will be described with reference to FIG. 16 and the like, in which the transmission side device detects the deterioration of the communication environment by performing transmission in the slot and performs control so that the communication quality can be maintained even when the communication environment deteriorates. To do.

  The basic configuration is the same as in the third embodiment, and the configuration of the in-vehicle multimedia wireless communication system in the present embodiment is as shown in FIG. The configurations of the central control unit 1, the monitors 4 to 8, and the RSE 2 are shown in FIGS. 11, 17, and 18, respectively. The difference from the third embodiment is that the central control unit 1, the RSE 2 and the monitors 4 to 8 that receive data include the communication environment index value of the communication involving the own device in the beacon slot and transmit, The central control unit 1, RSE2, and CMR3 that transmit data change the communication method based on the transmitted communication environment index value.

  The transmission data rate of the WiMedia Alliance multiband orthogonal frequency division multiplexing (MB-OFDM) system is defined as 53.3 Mbps, 80 Mbps, 106.7 Mbps, 160 Mbps, 200 Mbps, 320 Mbps, 400 Mbps, and 480 Mbps. The modulation scheme of 200 Mbps or higher employs DCM (Dual Carrier Moduration), and the lower modulation scheme employs QPSK (quadri-phase shift keying) modulation, and the coding rate is defined for each transmission rate. In addition, FDS (Frequency Domain Spreading), which improves the resistance against frequency selective fading by transmitting the same data using different frequency carriers, is adopted in 53.3 and 80 Mbps, and the same data is time-divided twice. Introducing TDS (Time Domain Spreading) that increases the resistance to interference between adjacent beacon groups at a transmission data rate of 200 Mbps, for example, to cope with the deterioration of the communication environment for each transmission data rate of 200 Mbps or less It is included.

  “Communication III DRP transfer example when communication environment is good” in FIG. 16 is a communication method capable of data rate communication of a maximum of 400 Mbps in a favorable communication environment of any communication III in the beacon group, and uses 6 MAS. This is an example in which communication is performed using the DRP transfer method. On the other hand, “Communication IIIa DRP transfer example 1 when the communication environment deteriorates” is 12 MAS in a communication method capable of data rate communication of a maximum of 200 Mbps in a state where the communication environment of any wireless communication device communication III in the beacon group is deteriorated. "Communication when communication environment deteriorates IIIb DRP transfer example 2" in a state where DRP transfer is performed using a data rate of up to 200 Mbps when communication between any wireless communication devices in a beacon group is in a deteriorated communication environment This shows a state in which communication is performed by a DRP transfer method using 6MAS in a communication method capable of communication.

  When communicating between each wireless communication device, the RSSI and LQI are normally calculated by the receiving device. Generally, RSSI is the signal strength of the received signal. If this value is large, the level of the received signal is high = the quality of the received signal is high. The LQI is considered to be the S / N of the received signal, and in an environment where the LQI is low, it is considered an environment where there are many noise components. For this reason, when RSSI becomes low or LQI becomes low, the communication quality between apparatuses may not be maintained, and it is necessary to perform control to cope with the deterioration of the communication environment in the transmitting side wireless communication apparatus.

  As a means for transmitting the RSSI or LQI calculated on the receiving side to the transmitting side, there is a method of including RSSI or LQI in data communication by the PCA transfer method. However, in the PCA transfer method, communication is performed during a data transmission / reception enabled period. Somewhat consumes communication bandwidth. Therefore, by including it in the beacon slot transmitted in the beacon period, it is possible to notify the transmission-side wireless communication device of information regarding the communication environment without consuming the communication band during the data transmission / reception possible period.

  If the transmission side device that knows the deterioration of the communication environment from the communication environment index value sent in the beacon from the reception side device determines that the communication quality cannot be ensured at 400 Mbps of communication III, it secures the communication band. If sufficient MAS is left, the modulation method is changed from DCM to QPSK and the transmission rate adopts TDS as shown in the figure “Communication IIIa DRP transfer example 1 when communication environment deteriorates”. The transmission rate is changed to 1/2 of 200 Mbps. In order to secure the data transfer capacity in units of superframes, the number of used MASs is doubled to 12, thereby ensuring the communication quality against the deterioration of the communication environment.

  In addition, when the compression rate is increased and the data rate is lowered to 1/2 in the transmission side wireless communication device, the necessary MAS is set to “when the communication environment is good” as in “Communication IIIb DRP transfer example 2 when communication environment deteriorates”. Can be the same as “Communication III DRP transfer example”. For this reason, the number of unreserved MASs is larger than that in the transfer example 1, and therefore, retransmission performed when an error occurs on the receiving side is performed in the unreserved MAS, so that more retransmissions can be performed. It becomes like this. As a method for facilitating retransmission, it is possible to make the data frame smaller.

  Further, when a wireless communication device is mounted on a vehicle, it is considered that many reception paths are generated due to reflection in the vehicle. In particular, when the transmitting side is arranged at a position that cannot be directly seen when viewed from the receiving-side wireless communication device side, communication between devices is established by reflected waves in the vehicle. When communication environment deterioration information is passed to the transmission side in such a situation, the RF frequency used in the beacon group is changed to a lower RF frequency (which RF frequency in the beacon group The TFC (Time Frequency Code) is used as a value indicating whether or not to use, and the RF frequency to be used is determined by this value. The level goes up. Since UWB uses RF frequencies over a wide range from about 3.5 GHz to about 10 GHz, it is possible to reduce losses due to reflection and the like by switching from 10 GHz communication to communication using 3.5 GHz RF frequency. .

  Regarding the position to include the communication environment index value in the beacon slot, any IE-specific field of ElementID252 to 255 in the Information Element arranged in the beacon payload, or Device control arranged in the beacon payload Send it in the field.

  As described above, by including a communication environment index value such as RSSI or LQI calculated by the receiving side in the beacon slot, the transmitting side wireless communication device can determine the communication environment between the devices, and the transmission method can be further improved. Maintaining the communication quality within the beacon group even in a deteriorated communication environment by changing to a method that is resistant to deterioration, changing the data frame to be easy to retransmit, and controlling the RF frequency to be used I can do it.

  In addition, if it is found that the data content of communication between wireless communication devices is terrestrial digital broadcast content and the communication environment between devices communicating terrestrial digital broadcast content has deteriorated, the transmitting side wireless communication device Instead of changing the compression rate, changing the data rate from full seg to one seg data rate reduces the transmission data rate from about 20 Mbps to several hundred kbps, enabling more retransmissions, It may be possible to control to change to a transmission data rate that is resistant to changes in the communication environment.

  In terrestrial digital broadcasting, both full seg with a data rate of about 20 Mbps and one seg with low image quality of several hundred kbps but capable of mobile reception are transmitted from broadcast stations for high-quality broadcasting. For this reason, Full Seg and One Seg have the same content with different image quality. If the deterioration of the communication environment can be detected between devices communicating digital terrestrial broadcast content in the beacon group using this simulcast broadcast, the transmitting-side wireless communication device changes from full segment to one segment. In this way, if the data rate to be transmitted is lowered and a stronger modulation method is selected against the deterioration of the communication environment, or if an error occurs on the receiving side, more retransmissions can be performed to transmit the same data again. In addition, the data frame configuration is reduced.

  For example, the central control unit receives a communication environment index value such as RSSI or LQI transmitted from a wireless communication device in the same beacon group using a beacon slot, and the communication environment index value indicates a deterioration of the communication environment. If there is, the central control unit instructs one of the wireless communication apparatuses that transmit full segment data in the same beacon group to switch from transmission of full segment data to transmission of one segment data. The switching instruction from the full segment data to the one segment data is transmitted from the central control unit to the wireless communication apparatus that transmits the full segment data using the beacon slot. A signal indicating that the transmitting side wireless communication device that transmits full segment data or the receiving side wireless communication device that receives the data uses the beacon slot during transmission / reception of full segment data and that the device is transmitting / receiving full segment data. Is notified to the central control unit in advance, so that the central control unit can recognize in advance the wireless communication apparatus that is transmitting full segment data.

  Alternatively, a receiving wireless communication device that receives full segment data transmits a communication environment index value to the transmitting wireless communication device that transmits the full segment data using a beacon slot, and the transmitting wireless communication device transmits the communication environment index value. When the deterioration of the communication environment is detected by the value, the transmission of the own full-segment data may be switched to the transmission of the one-segment data based on the determination of the transmitting side wireless communication device itself, not the central control unit. When the transmission side wireless communication apparatus switches from full segment data transmission to one segment data transmission, a signal indicating that the transmission side wireless communication apparatus switches from full segment data transmission to one segment data transmission is a beacon. You may make it transmit to a receiving side radio | wireless communication apparatus using a slot.

  As described above, by including information on whether the communication data content between devices is terrestrial digital broadcast content full-segment or one-segment, in the beacon slot, the compression rate can be changed when the communication environment between devices deteriorates. First, by changing the data on the sending side from full seg to one seg, the data rate is lowered, it is changed to a stronger transmission data rate against the deterioration of the communication environment, or it is made communication that allows more retransmission, When the communication environment deteriorates, the image quality can be lowered and communication between devices can be maintained before normal communication cannot be performed.

Embodiment 6 FIG.
Next, content type information indicating whether the content of data to be communicated is content such as DVD, CD, game, broadcast, telephone, portable terminal, camera video, other video, other audio, etc. 19 in the beacon transmitted from each wireless communication device, and when the communication environment is detected to be deteriorated, control is performed so that the communication band is secured in preference to the communication of the content with high priority as shown in FIG. It explains using.

  The basic configuration is the same as that of the third embodiment. In the in-vehicle wireless communication system of FIG. 1, each occupant can arbitrarily select a favorite content from contents such as DVD, CD, game, broadcast, telephone, mobile terminal, camera video, other video, and other audio. It is like that. The difference from the third embodiment is that the RSE 2 and the monitors 4 to 8 indicate the content type information indicating which type of communication content the own apparatus is involved in, among the content types, the beacon slot. And the determination unit 311 of the central control unit 1 determines the MAS arrangement based on the transmitted content type information.

  FIG. 19 shows an example of “transmission of communication IVDRP when the communication environment is good” in which communication IV and communication V are performed when the communication environment is good. Diagram of “Communication VaDRP transfer example when communication environment deteriorates” changed to maintain communication quality by temporarily changing communication method to maintain communication quality of communication Va and increasing communication bandwidth It is. Based on this figure, an example of the MAS arrangement determination method performed by the determination unit 311 will be described below.

  For example, the communication IV has a DVD_HD content playback function on the transmission side by the beacon transmitted from each wireless communication device, the communication transmits content data of HD image quality, and communicates video from the in-vehicle camera. When the presence of the communication V is broadcast in the beacon group, when the RSSI or LQI on the receiving side of the communication IV or V is lowered due to disturbance, between devices including a function that can be temporarily stopped Priority is given to the communication of and paused.

  The policy for stopping communication is communication between devices that also have a function of reproducing data from the paused position when data is first paused on the transmission side and then restored, and communication with a high transmission data rate is given first priority. Therefore, the communication is temporarily stopped. In addition, communication between devices that maintains communication as much as possible is considered to be broadcast, in-vehicle camera, telephone, or the like that can be considered as continuous streaming data.

Temporarily stop communication temporarily in order of highest priority (highest priority) DVD_HD>DVD_SD>game> CD ...
The order of the highest priority to maintain communication (highest priority) phone (mobile)> in-vehicle camera>broadcast> ...
And

  For example, assuming that communication IV = DVD_HD and communication V = vehicle-mounted camera in FIG. 16, the playback operation of DVD_HD having the operation pause function is temporarily stopped, and communication IV is temporarily stopped. By temporarily stopping, the MAS reserved in communication IV is released. Therefore, in order to ensure the communication quality of communication V including this vacant band, the transmission data rate is halved and retransmitted. By reducing the data frame so that it is easy to occur, it is possible to maintain the remaining communication (Va) as much as possible by changing to a transmission method that is more resistant to changes in the communication environment.

  In the present embodiment, the central control unit 1 shown in FIG. 11 receives the content type information included in the beacon slot and transmitted from the antenna 300 from other wireless communication devices in the beacon group, and receives the receiving unit. In 301, it is possible to know the type of communication content involved in each wireless communication device. Next, the determination unit 311 determines the MAS arrangement by the method as described above based on the information. The determined MAS arrangement is included in the beacon slot via the transmission unit 308, and transmitted from the antenna 300 to the RSE2 and CMR3. The RSE2 and CMR3 that have received the determined MAS arrangement perform data transmission accordingly.

  As described above, the content type information of the data to be communicated is included in the beacon slot transmitted from each wireless communication device. Therefore, when the communication environment deteriorates, the MAS arrangement is prioritized according to the content type. By doing so, it is possible to change to a communication system having resistance due to changes in the communication environment. In particular, by temporarily suspending communication from a device with a pause function and releasing the number of MAS used, other communications can be changed to a communication method that is more resistant to changes in the communication environment. Can do.

Embodiment 7 FIG.
Next, in the vehicle as shown in FIG. 1, the number of passengers in the vehicle is detected, and the detection result is input to a wireless communication device having a function such as control that is central in the vehicle. In the seventh embodiment, the communication data quality within the beacon group can be maintained by changing the transmission data rate to a method more resistant to changes in the communication environment by changing the data compression rate, etc. To do.

  The in-vehicle wireless communication devices of the central control unit 1, RSE2, CMR3, and monitors 4 to 8 in the vehicle shown in FIG. 1 form one beacon group and perform communication by UWB between the wireless communication devices. . Since UWB is a wireless system that can realize high-speed data communication even in short-distance communication, a state in which communication is performed between wireless communication devices that are communicating with each other is considered a good communication environment. In addition, when placed outside the line-of-sight, compared to the case where it can be received within the line-of-sight, communication will be established by a delayed wave in which power loss occurs due to reflection, etc. However, the communication environment is thought to be worse.

  When a total of four people (two front seats / two rear seats) get on the vehicle shown in FIG. 7, for example, communication from the CMR 3 to the central control unit 1 may be out of sight. If the communication is out of line of sight, the central control unit 1 receives the delayed wave generated by the reflection in the vehicle from the signal from the CMR 3, and it is assumed that the quality of the received signal is deteriorated.

  If the central control unit 1 is a device having a control function or the like which is central in the vehicle, information on the number of passengers in the vehicle is concentrated on the central control unit 1 and a beacon is transmitted by a beacon transmitted by the central control unit 1. Information on the number of passengers in a group can be multicast. When CMR3 obtains the information and recognizes the number of passengers and determines that there is a high possibility of non-line-of-sight communication between the central control unit 1 and the CMR3, the compression rate is increased and the data rate of the in-vehicle camera is decreased. The communication of the camera can be maintained by controlling the transmission method to be more resistant to changes in the communication environment and changing to a data frame that allows more retransmission.

  As described above, the number of passengers is detected, information on the number of passengers is input to the central control unit 1, and the information is multicast to each wireless communication device in the beacon group by using a beacon. When it is determined that there is a high possibility of non-line-of-sight communications from internal communications, by increasing the compression rate and lowering the transmission data rate, it is possible to change to a transmission method that is more resistant to changes in the communication environment. Even in communications that are likely to be out-of-line communications, communication quality can be maintained.

  Here, a case has been described in which the central control unit multicasts information on the number of passengers and the CMR changes the data rate based on the multicast information. However, the present invention is not limited to this, and the central control unit determines whether the number of passengers in the vehicle to be input. Based on this, priority is given to a device that affects safety, such as CMR, and a DRP transfer MAS to be assigned to each wireless communication device is determined, and the central control unit includes the information on the MAS arrangement in a beacon slot for multicasting. May be.

Embodiment 8 FIG.
Next, by inputting vehicle information such as vehicle speed information, back gear operation, turn signal operation, and side brake operation information to a device with functions such as control at the center of the vehicle, an image is output from the in-vehicle camera. Embodiment 8 will be described in which a communication band necessary for the communication of the video data is preferentially secured.

  In conventional in-vehicle communication devices, when using a back gear or using a blinker at low speed, an in-vehicle camera mounted on the vehicle is used to display the vehicle rear area on the monitor, Displaying the area on the monitor may assist the driver's viewing angle. If communication of this video data is delayed or video displayed at an extremely low data rate may lead to an accident, it is desirable to secure MAS in preference to other communications. Therefore, the central control unit 1 detects an operation such as using a back gear or using a blinker at a low speed, and if detected, a low delay is required for the MAS arrangement immediately before the in-vehicle camera is added. Place the MAS giving priority to the in-vehicle camera video.

  The basic configuration is the same as in the third embodiment, and the configuration of the in-vehicle multimedia wireless communication system in the present embodiment is as shown in FIG. The configurations of the central control unit 1 and the CMR 3 are shown in FIGS. 20 and 4, respectively. The difference from the third embodiment is that the central control unit 1 has a vehicle information detection unit 315, and the determination unit 311 detected there refers to vehicle speed information, back gear operation, turn signal operation, and side brake operation information. Thus, the MAS arrangement is determined.

  Next, the operation will be described. In the central control unit 1 shown in FIG. 20, the vehicle information detection unit 315 detects that the back gear is used or the winker is used at a low speed, and sends an input signal to the determination unit 311. The determination unit 311 prioritizes data communication of the CMR 3 and determines the MAS arrangement. Subsequent operations are the same as those in the third embodiment.

  As described above, vehicle information such as vehicle speed information, back gear operation, turn signal operation, and side brake operation is input to a device having a control function or the like in the vehicle, and the device performs wireless communication based on the information. Since the MAS for DRP transfer assigned to communication between devices is determined and the determined MAS arrangement is transmitted to each wireless communication device using a beacon slot, the priority order of the vehicle-mounted camera or the like is given to the communication within the beacon group. It is possible to determine in advance that high video communication will be added. Prior to video output from the in-vehicle camera, the communication bandwidth required for communication between devices in the BG will be given priority to in-vehicle camera communication. Secure and display on-board camera video quickly.

It is a block diagram which shows the multimedia wireless communication system for vehicles in this invention. 3 is a block diagram illustrating a configuration of a monitor according to Embodiment 1. FIG. It is a block diagram which shows the structure of the central control unit in Embodiment 1, and a rear seat entertainment. 1 is a block diagram illustrating a configuration of an in-vehicle camera in Embodiment 1. FIG. It is a block diagram of a super frame of WiMedia Alliance. It is the figure which showed the structural example of the PHY frame structure of WiMedia Alliance. It is the figure which showed the kind of Information element prescribed | regulated with the multiband orthogonal frequency division multiplexing (MB-OFDM) system of WiMedia Alliance. It is the figure which showed the structure of Information element. It is the figure which showed the structure of the beacon area and beacon group of the some UWB apparatus in Embodiment 1. FIG. FIG. 10 is a layout diagram of a superframe configuration and PCA transfer for the second embodiment. FIG. 10 is a block diagram showing a configuration of a central control unit in a third embodiment. FIG. 10 is a diagram of a MAS arrangement example of a superframe configuration and a DRP transfer method for the fourth embodiment. FIG. 10 is a block diagram illustrating a configuration of a monitor according to a fourth embodiment. It is a block diagram which shows the structure of the rear seat entertainment in Embodiment 4. FIG. FIG. 10 is a block diagram illustrating a configuration of an in-vehicle camera in a fourth embodiment. FIG. 10 is a diagram of a MAS arrangement example of a superframe configuration and a DRP transfer scheme for the fifth embodiment. FIG. 10 is a block diagram illustrating a configuration of a monitor according to a fifth embodiment. FIG. 10 is a block diagram showing a configuration of rear seat entertainment in a fifth embodiment. FIG. 10 is a diagram of a MAS arrangement example of a superframe configuration and a DRP transfer scheme for the fifth embodiment. FIG. 20 is a block diagram showing a configuration of a central control unit in an eighth embodiment.

Explanation of symbols

1 central control unit, 2 rear seat entertainment, 3 on-board camera, 4 monitor, 5 monitor, 6 monitor, 7 monitor, 8 monitor, 200 antenna, 201 receiving unit, 202 decoding unit, 203 video / audio output unit, 204 encoding Information generation unit, 205 transmission unit, 206 UWB device, 210 communication environment index value calculation unit, 213 allowable delay amount calculation unit, 300 antenna, 301 reception unit, 302 decoding unit, 303 video / audio input / output unit, 304 encoding Information generation unit, 306 control unit, 308 transmission unit, 309 UWB device, 310 communication environment index value calculation unit, 311 determination unit, 313 allowable delay amount calculation unit, 315 vehicle information detection unit, 400 antenna, 401 reception unit, 403 camera Unit, 405 encoding unit, 406 control unit, 408 transmission unit, 409 WB device, 413 allowable delay amount calculation unit, 441 UWB device existing outside vehicle, communication range of 81 UWB device 206a, communication range of 82 UWB device 206b, communication range of 83 UWB device 309, 84 UWB device 441 Communication range.

Claims (18)

A receiver for receiving the encoded data;
An encoding information generation unit for generating data compression rate information and / or data rate information for instructing a data compression rate and / or data rate used for the encoding to another wireless communication device that transmits the data; ,
A transmission unit that transmits data compression rate information and / or data rate information output from the encoded information generation unit in a beacon slot of a multiband orthogonal frequency division multiplexing (MB-OFDM) system;
A wireless communication apparatus comprising: a decoding unit that decodes data received by the receiving unit. 2. The wireless communication apparatus according to claim 1, wherein the MB-OFDM beacon slot is a WiMedia Alliance multi-band orthogonal frequency division multiplexing (MB-OFDM) beacon slot. The transmitting unit transmits the data compression rate information and / or data rate information by including it in an IE-specific field of ElementID 252 to 255 among information elements arranged in a beacon payload in the beacon slot. The wireless communication apparatus according to claim 2. The radio according to claim 2, wherein the transmission unit includes the data compression rate information and / or the data rate information in a Device control field arranged in a beacon payload in the beacon slot. Communication device. The transmission unit transmits data compression rate information and / or data rate information output from the encoded information generation unit by selectively using one of a beacon slot and a PCA transfer slot. The wireless communication apparatus according to claim 1. Data compression rate information and / or data rate information transmitted from each of the plurality of wireless communication devices in the same beacon group including the wireless communication device according to any one of claims 1 to 5 in a beacon slot. , Determine a DRP transfer MAS to be allocated to communication between the wireless communication devices based on the received information, and transmit the determined MAS arrangement to each wireless communication device using a beacon slot A centrally controlled wireless communication device characterized by: A receiver for receiving the encoded data;
An allowable delay amount calculation unit that outputs delay information relating to an allowable delay amount; and
A transmission unit for transmitting the delay information output from the allowable delay amount calculation unit in a beacon slot of a multiband orthogonal frequency division multiplexing (MB-OFDM) system;
A wireless communication apparatus comprising: a decoding unit that decodes data received by the receiving unit. The wireless communication device according to claim 7 receives delay information transmitted by being included in a beacon slot, and based on the received delay information, among the communication between any wireless communication devices of the same beacon group, a low delay request A central control radio communication apparatus characterized in that a plurality of MASs are distributed and assigned in a superframe preferentially for the selected low-delay request communication. A receiver for receiving the encoded data;
A calculation unit that outputs an index value of the communication environment;
A transmitter that includes the calculated index value of the communication environment in a beacon slot of a multiband orthogonal frequency division multiplexing (MB-OFDM) scheme;
A wireless communication apparatus comprising: a decoding unit that decodes data received by the receiving unit. The wireless communication device according to claim 9, wherein the wireless communication device receives an index value of the communication environment that is included in a beacon slot and transmits the beacon slot, and based on the received communication environment index value, At least one of a modulation method used in communication between wireless communication apparatuses, a transmission rate, the number of MAS used in the communication, a data compression rate, a data rate, a data frame capacity, a used transmission frequency, and a selection of full segment / one segment. A central control wireless communication apparatus characterized by the above. The radio communication apparatus according to claim 9 or 10, wherein full-segment / one-segment selection information is included in a beacon slot of a multiband orthogonal frequency division multiplexing (MB-OFDM) scheme and transmitted. 10. The wireless communication device according to claim 9, wherein the wireless communication device receives the index value of the communication environment that is transmitted by being included in a beacon slot, and based on the received communication environment index value, at least one of the wireless communication devices And decides to switch the full-segment data transmission in the communication between the full-seg system to the one-segment system, and includes the instruction to switch from the full-segment system to the one-segment system in the beacon slot of the multiband orthogonal frequency division multiplexing (MB-OFDM) system. A central control wireless communication device for transmitting data to a wireless communication device on a transmission side and / or a wireless communication device on a reception side of system data transmission. A receiver for receiving the encoded data;
A transmitter that transmits content type information of data to be communicated in a beacon slot of a multiband orthogonal frequency division multiplexing (MB-OFDM) system;
A wireless communication apparatus comprising: a decoding unit that decodes data received by the receiving unit. Receiving type information of contents transmitted or received by each wireless communication device included in a beacon slot and transmitted from a plurality of wireless communication devices in the same beacon group including the wireless communication device according to claim 13 Then, based on the received information, a central control radio communication apparatus that determines a DRP transfer MAS to be assigned to communication between the radio communication apparatuses. A wireless communication device including the wireless communication device according to claim 13 that is included in a beacon slot and transmitted from a plurality of wireless communication devices in the same beacon group. Central control wireless communication characterized in that information is received and, based on the received information, priority is given to content that cannot be paused, and a MRP for DRP transfer assigned to communication between wireless communication devices is determined. apparatus. 16. Information on the number of passengers in a vehicle is input, and the input information is included in a beacon slot of a multiband orthogonal frequency division multiplexing (MB-OFDM) system and transmitted. A wireless communication device according to 1. 17. A wireless communication apparatus that receives information on the number of passengers included in the beacon slot from the wireless communication apparatus according to claim 16, and switches communication of the own apparatus to a different transmission method based on the received information. Any information of change information to back gear, vehicle speed information, turn signal state information, and / or side brake state information is input, and each wireless communication device in the same beacon group based on the input information A central control radio communication apparatus characterized by determining a DRP transfer MAS to be allocated to communication between the two, and transmitting the determined MAS arrangement to each radio communication apparatus using a beacon slot.

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