JPH0927951A - Radio video communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the transmission speed of video information without increasing the system cost. SOLUTION: A radio video terminal equipment 17 generates control information to request video information. The control information includes a kind of video information on request, a transmission method of video information and a position registration request or the like. The radio video terminal equipment 17 sends the control information to a video server 11 via a control radio station 19 and a network 13 to request the video information. The video server 11 sends the video information on request to the radio video terminal equipment 17 requesting the video information via the network 13, a video information relay section 14 and a video radio station 15 by using a designated channel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless video communication system, and more particularly to avoiding a congestion state on a communication path caused by a huge amount of video information from a video server and control information from a large number of terminal stations. Possible wireless video communication system.

[0002]

2. Description of the Related Art FIG. 13 is a block diagram showing a configuration example of a conventional wireless video communication system. In FIG.
The wireless video communication system includes a video server 121, a video information relay unit 123 connected to the video server 121 via a network 122, a plurality of wireless LAN base stations 124, and a plurality of wireless video terminals 125. There is.
Further, each wireless LAN base station 124 has a unique zone 12
6 and can communicate only with the wireless video terminal 125 existing in the zone 126. However, each wireless video terminal 125 can move across all the zones 126, and the wireless LA having the zones 126 can move.
It is possible to communicate with the N base station 124. Hereinafter, the configuration of each unit of the conventional wireless video communication system will be described in more detail with reference to FIG.

The video server 121 transmits menu information including a title of video information to the wireless LAN base station 124 so that the wireless video terminal 125 can search for video information contained therein. Further, the video server 121 distributes the video information contained therein to the wireless video terminal 125 in accordance with the request from the wireless video terminal 125. Network 1
22 transmits menu information and video information input from the video server 121 to the video information relay unit 123. Also,
The network 122 transmits the control information output from the video information relay unit 123 to the video server 121.

The video information relay section 123 is connected to the network 1
The menu information and the video information transmitted via 22 are distributed to each wireless LAN base station 124 according to their contents. That is, the video information relay unit 123
Including switch function. In addition, the video information relay unit 123
The video server 12 collects control information from each wireless video terminal 125 output from each wireless LAN base station 124.
Output to 1.

The wireless LAN base station 124 directly distributes menu information and video information to the wireless video terminal 125.
In addition, the wireless LAN base station 124 has a wireless video terminal 125 in a zone 126 of the wireless LAN base station 124.
The control information is collected and output to the video information relay unit 123. The wireless video terminal 125 is the wireless LAN base station 12
After determining the video information desired to be transmitted from the menu information distributed from the wireless LAN base station 124, a control signal including a video information request to the video server 121 is transmitted.
Output to

In the wireless video communication system having the above structure, the wireless video terminal 125 is connected to the video server 1.
The procedure from 21 to receiving the video information distribution is as follows.
This will be described in detail.

The video server 121 always outputs the menu information including the title of the video information contained therein to the video information relay section 123 via the network 122. The video information relay unit 123 separates the received menu information into menu information for each wireless LAN base station 124. Then, the video information relay unit 123 outputs the menu information to each wireless LAN base station 124. Each wireless LAN base station 124 outputs the received menu information to the zone 126 managed by itself.

The wireless video terminal 125 has a zone 126.
When entering the, the menu information output in the zone 126 is received. When there is video information that the video server 121 wants to be supplied in the received menu information, the wireless video terminal 125 outputs a control signal designating the video information desired to be transmitted to the wireless LAN base station 124. . From the control signal transmitted via the wireless LAN base station 124, the video information relay unit 123 and the network 122, the video server 121
The user desires to transmit the video information from the wireless video terminal 125, recognizes the corresponding video information, and outputs it. This video information is sent to the wireless video terminal 12 via the network 122, the video information relay unit 123 and the wireless LAN base station 124.
5 will be delivered.

[0009]

As described above, in the conventional wireless video communication system, each wireless LAN base station 124
Performs transmission / reception processing of video information and transmission / reception processing of control information. Since the video information and the control information are transmitted using the same communication path, each wireless LAN base station 12
No. 4 cannot simultaneously perform the transmission / reception processing of the video information and the transmission / reception processing of the control information. Therefore, each wireless LAN base station 124 must interrupt the transmission / reception processing of the video information and execute the transmission processing of the control information every time the control information is received. In this case, the transmission speed of the video information is reduced, and the received video is interrupted in the wireless video terminal 125. In particular, a large number of wireless video terminals 125 within the same zone.
Is present and control information is simultaneously transmitted from a plurality of wireless video terminals 125, this problem becomes serious.

Since the amount of video information is much larger than that of control information, the conventional wireless video communication system for transmitting both via the same communication path does not effectively utilize the band allocated as the communication path. It will be. In addition, each wireless LA
By replacing the CPU of the N base station 124 with a high-speed CPU and increasing the transmission speed of video information, the wireless video terminal 1
It is conceivable to eliminate the discontinuity of the received image at 25, but such a method increases the system cost and is difficult to realize.

In a conventional wireless video communication system,
The control information is transmitted to the video server 121 regardless of the traffic volume of the video information on the network 122. As a result, when a large number of wireless video terminals 125 transmit control signals to the video server 121 at approximately the same time,
The video server 121 must control distribution of a large amount of video information in response to the control signals. However, since the amount of video information data is enormous, the traffic increases over the network 122, and it becomes difficult for the video server 121 to control the distribution of the video information. That is, a congestion state occurs in the video server 121. As described above, the conventional wireless video communication system also has a problem that the load on the video server 121 is increased.

Further, when the wireless video terminal 125 moves to another zone 126 while receiving the supply of the video information, the video server 121 cannot recognize the movement of the wireless video terminal 125 and the zone before the movement. The video information will be continuously transmitted to 126. Therefore, the wireless video terminal 125 that has moved to another zone cannot receive this video information. Therefore, the video server 121 will transmit useless video information. This is also network 1
22 caused an increase in traffic, and the video server 121
This will increase the burden on the

For reference, some of the other conventionally proposed video communication systems will be introduced below.

(1) Japanese Patent Application Laid-Open No. 4-332284 The device disclosed in this publication accommodates incidental signals such as a meeting line signal, a supervisory control signal, and a line switching signal in the same base band as the television video signal. It is a device adapted to send and receive. However, when transmitting digital video information wirelessly, a very wide transmission band is required, and it is difficult to multiplex and transmit control information other than video information.

(2) US Pat. No. 5,325,419 In the system disclosed in this publication, a wireless station to which a mobile terminal is wirelessly connected is connected to an ISDN line, thereby communicating voice, data and images. It is a system that does.
However, since this system multiplexes voice, data, and images on one communication line and sends them, the bandwidth is insufficient when trying to transmit high-quality images.

(3) US Pat. No. 5,172,413 In the system disclosed in this publication, video information is hierarchically distributed and stored according to the frequency of user's access, and video information is requested in response to a plurality of user requests. It is a system that provides information. However, this system is premised on a wired network as a transmission medium, and a user's terminal is fixedly arranged and cannot be freely carried.

(4) US Pat. No. 5,101,267 The system disclosed in this publication analyzes a user's request in real time by satellite broadcasting and responds to the request. In this system, a base station that transmits video information and a base station that transmits control information are different, but video information and control information are transmitted to each base station in the same wireless band.

It is an object of the present invention to provide a wireless video communication system capable of improving the transmission speed of video information without increasing the cost of the system. Another object of the present invention is to provide a wireless video communication system capable of preventing an increase in traffic on the network due to the concentration of control signals and reducing the load on the video server. Still another object of the present invention is to provide a wireless video communication system capable of managing the position of a wireless video terminal and thereby reducing the load on the video server.

[0019]

The present invention is directed to a wireless video communication system for wirelessly distributing various video information to a movable terminal station, and stores a plurality of types of video information. Connected to the video server via the network, the video wireless station transmitting video information supplied from the video server to the terminal station via the first wireless communication path, and the video wireless station from the terminal station to the second station. The control wireless station which receives the control information transmitted via the wireless communication path and notifies the video server of the control information. The terminal station
By transmitting the control information, the fact that the video information is requested and the type of the requested video information are transmitted. The video server, based on the control information received from the control radio station,
It retrieves the corresponding video information and outputs it on the network. A relatively wide band is allocated to the first wireless communication path, and a relatively narrow band is allocated to the second wireless communication path. In this way, the video information and the control information are
It is transmitted via different wireless communication paths. Therefore, the video wireless station does not need to process the control information, and can perform the transmission / reception process of the video information without interruption. As a result, the video wireless station can effectively utilize the allocated band and prevent the transmission speed of the video information from decreasing.

When the video wireless station can use a plurality of communication channels in the first wireless communication channel to transmit the video information, the terminal station receives the video information by transmitting the control information. Specify the communication channel for. In this case, the video wireless station is monitoring the current use status of the communication channel, and when the control wireless station receives the control information, it determines whether the communication channel specified by the control information can be used. Contact the station. Then, if the designated communication channel can be used, control information is transmitted to the video server, and if it cannot be used, the terminal station is requested to reset the communication channel for reception. The video wireless station transmits the video information supplied from the video server to the terminal station using the communication channel designated by the terminal station. As a result, the video server does not have to perform the video information distribution process that exceeds the capacity of the communication channel, so that it is possible to prevent a congestion state and keep the traffic volume on the network appropriate.

In a general operation, a plurality of video radio stations are installed and each has a unique radio zone in which each of them can communicate. Then, the control wireless station can communicate in the area covering the wireless zones of all the video wireless stations. In this case, frequency bands that do not overlap with each other are fixedly allocated to each video wireless station as the first wireless communication path. Then, each video wireless station transmits video information using a plurality of communication channels obtained by dividing the frequency band fixedly allocated. This allows a large number of terminal stations to request video information.

In the preferred embodiment, menu storage means is further provided. The menu storage means is connected to each video wireless station and stores the title information of the video information stored in the video server. In this case, each video wireless station creates menu information created based on the title information stored in the menu storage means, an identification value assigned to each video wireless station, and communication in the first wireless communication channel. The channel usage status is transmitted to the wireless zone of the own station by using a predetermined communication channel in the first wireless communication path. The terminal station creates the control information by referring to the received menu information, the identification value, and the use status of the communication channel.

Preferably, the control information includes a video information number section for storing an identification value for specifying the video information requested to be delivered to the video server, and a terminal station for storing an identification value unique to the terminal station. An ID section, a first transmitting / receiving station ID section that stores an identification value of the video wireless station that has transmitted the menu information,
A use channel designating unit that designates a communication channel for receiving requested video information is included. In this case, the control wireless station inquires of the video wireless station having the identification value stored in the first transmitting / receiving station ID section whether the communication channel stored in the used channel designating section can be used. If the communication channel cannot be used, the terminal station having the identification value stored in the terminal station ID section is requested to reset the communication channel, and if the communication channel can be used,
Transfer control information to the video server. Video server
Refer to the video information number part of the transferred control information,
It retrieves the corresponding video information and outputs it on the network.

Also, in the preferred embodiment, position information storage means is provided. The position information storage means stores the identification value of the terminal station and the identification value of the video wireless station included in the control information received from the control wireless station by the video server. This makes it possible to manage the current position of each terminal. As a result, the video server can quickly and surely deliver the video information to the terminal station that has flown into any of the zones.

Further, the control information may include a position information registration flag portion for notifying the video server whether to request or delete the position information stored in the position information storage means. In this case, the video server
The contents of the position information storage means are changed with reference to the position information registration flag portion of the received control information. As a result, the video server does not perform unnecessary position information update processing.

[0026] Preferably, when the video server recognizes that the terminal station is not located in any zone based on the position information registration flag portion included in the received control information, the position information storage means outputs the terminal. Delete station location information. As a result, even if the video information is distributed in the wireless zone in which the terminal station was previously located, it is possible to cancel this. That is, the video server can control useless distribution of video information and can effectively use a limited number of communication channels.

Further, in a preferred embodiment, history information storage means for storing history of control information received by the video server as history information is provided. By accumulating such history information, investigation / statistics of access frequency,
It can be applied to counting questionnaires.

In another preferred embodiment, the controlling radio station is
Multiple units are provided, and each has its own communicable area. Further, a control device is provided for creating terminal station control information for controlling each terminal station and transmitting the terminal station control information via each control wireless station.
This control device collectively controls all the terminal stations located within the communicable area of all control wireless stations by giving the same shared identification value to each terminal station using the terminal station control information. That is, one terminal station control information can control many terminal stations in an integrated manner. As a result, the amount of traffic on the network is reduced.

The terminal station control information is preferably an identification value storage unit for storing an identification value or a shared identification value unique to each terminal station, and data for storing data for controlling each terminal station. And a storage unit. The control device individually controls each terminal station by using the terminal station control information including the identification value unique to each terminal station, and can communicate with all the control wireless stations by using the terminal station control information including the shared identification value. All terminal stations located in the area are collectively controlled. With this, the control device can individually control the terminal stations as necessary, or can control all the terminal stations.

[0030]

1 is a block diagram showing the overall configuration of a wireless video communication system according to a first embodiment of the present invention. 1, the wireless video communication system includes a video server 11, a position table unit 12 connected to the video server 11, a video information relay unit 14 connected to the video server 11 via a network 13, and a plurality of video information relay units 14. The video wireless station 15, a menu storage unit 16 connected to the video wireless station 15, a plurality of wireless video terminals 17, a control wireless station 19, and a history storage table unit 20 connected to the video server 11 are provided. There is. Although only one control radio station is shown in FIG. 1, it is sufficient to install an optimum number of control radio stations 19 according to the scale of the wireless video communication system. The configuration of each unit of the wireless video communication system according to the embodiment of the present invention will be described below with reference to FIG.

The video server 11 stores a plurality of types of video information, and according to a request from the wireless video terminal 17, retrieves corresponding video information and delivers it to the wireless video terminal 17. Also, the video server 11 is connected to each wireless video terminal 1
The position table section 12 (see FIG. 5) is used to grasp the zone 18 in which 7 is currently located. The position table section 12 will be described in detail later. The network 13 transmits various information used in this wireless video communication system. The video information relay unit 14 distributes various information transmitted via the network 13 to each video wireless station 15 according to the contents thereof.

The menu storage unit 16 connected to the video wireless station 15 stores information such as a title of video information that can be distributed to the zone 18 of each video wireless station 15. The video wireless station 15 has a menu information packet 31 including information stored in the menu storage unit 16 (see FIG. 3A).
Is generated and output to the zone 18 corresponding to the own station. The video wireless station 15 also includes a video information packet 32 including video information requested by the wireless video terminal 17 to the video server 11.
(See FIG. 3B) is created, and the video information is output to the requested wireless video terminal 17 using the free channel (see FIG. 2).

The wireless video terminal 17 includes a receiver 171, a transmitter 172, and a controller 173. Receiver 171
Is a first receiving the menu information packet 31 and the video information packet 32 transmitted from the video wireless station 15.
The receiving unit 171A and the second receiving unit 171B that receives the control wireless station control information transmitted from the control wireless station 19 are included. The control unit 173 displays the program menu included in the menu information packet 31 and the video information included in the video information packet 32 on a display (not shown).
If there is video information to be received, the user carrying the wireless video terminal 17 operates an input operation device (not shown) such as a keyboard to control the controller 173.
The video server 11 is instructed to request the video information. The control unit 173 creates a control information packet 41 (see FIG. 4) including this request and the like, and transmits it from the transmission unit 172 to the control wireless station 19.

The control wireless station 19 receives the control information 41 from the wireless video terminal 17. The control wireless station 19 transmits this control information 41 to the video server 11 via the network 13 and also sends it to the video wireless station 15 that manages the zone 18 to which the wireless video terminal 17 that created this control information packet 41 belongs. Send. The control radio station 19
Has a terminal station controllable area 110. This terminal station control area 110 is provided in all zones so that the position management can be performed even when the wireless video terminal 17 is located at a position where it cannot receive the menu information packet 31 from all the video wireless stations 15. Covers 18.

FIG. 2 is a diagram showing the frequency spectrum 21 of the transmission signal (including the menu information packet 31 or the video information packet 32) of each video wireless station 15 in FIG. In the wireless video communication system according to the present embodiment, each of the video wireless stations 15 does not overlap with each other.
A frequency band of 6 MHz is assigned to each. Further, in this frequency band, 512 carriers are included, and 40 carriers form one channel 2.
Make up 2. For example, in response to a request from the wireless video terminal 17, the video server 11 uses the MPEG of 1.5 Mbps.
(MotionPicture Experts Gr
video information compressed by the OFDM method (orthogonal frequency division multiplexing method: Orthogonal).
Frequency Division Multip
lexing). The video wireless station 15 uses the one unused channel 22 to send the video information packet 32 to the wireless video terminal 1 that has issued the video information request.
Send to 7 by radio wave. Also, the menu information packet 31
Are transmitted to the zone 18 using a preset channel 22.

Information transmission between each video radio station 15 and each radio video terminal 17 may be performed in the form of an analog signal which is AM-modulated or FM-modulated. In addition, information may be transmitted by an optical signal obtained by modulating infrared rays.

FIG. 3 is a diagram showing a detailed frame structure of the menu information packet 31 and the video information packet 32 included in the output signal of each video wireless station 15. FIG.
In (a), the menu information packet 31 includes a first video wireless station ID section 311 and an empty channel flag section 312.
And a program menu section 313. Each video radio station 15
Is assigned a unique identification value in advance. This identification value is stored in the first video / wireless station ID portion 311. As a result, the wireless video terminal 17 that has received the menu information packet 31 is in the zone 1 where it is currently located.
8 can be recognized. Free channel flag section 31
2 stores flag information indicating the usage status of each channel 22 in the frequency spectrum 21 assigned to the video radio station 15. The wireless video terminal 17 designates an unused channel by referring to this flag information and receives the video information packet 32 from the unused channel. In the program menu section 313, each video wireless station 15
A menu of video information that can be distributed is stored. The menu information packet 31 having the above-described configuration is transmitted with the free channel flag section 312 updated every time the video wireless station 15 delivers the video information packet 32 to the wireless video terminal 17.

In FIG. 3B, the video information packet 3
2 includes a video information section 321. This video information section 321
The video information requested by the wireless video terminal 17 to the video server 11 is stored in the. The wireless video terminal 17 demodulates this video information and displays the video on a display (not shown). Here, the video server 11 is the wireless video terminal 1
This video information packet 32 is distributed using the channel 22 requested by the No. 7. Therefore, the video information packet 32 does not require a storage unit for storing the identification value of the wireless video terminal 17 or the like.

FIG. 4 shows each wireless video terminal 17 in FIG.
However, when requesting video information from the video server 11,
6 is a diagram showing a detailed frame configuration of a control information packet 41 transmitted to the control wireless station 19. FIG. In FIG. 4, the control information packet 41 includes a terminal ID section 411, a second video wireless station ID section 412, a program number section 413, a used channel number section 414, a position information registration flag section 415, and a transmission data section. 416 and. The terminal ID section 411 stores the identification value of the wireless video terminal 17 that transmits the control information packet 41. In the second video radio station ID section 412,
The identification value of the video wireless station 15 that manages the zone 18 in which the wireless video terminal 17 is currently located is stored. Program number section 41
In 3, the identification value of the video information requested by the wireless video terminal 17 is stored. The used channel number section 414 stores an identifier such as the number of the channel 22 used when the video information requested by the wireless video terminal 17 is received. The position information registration flag unit 415 stores a flag indicating that the wireless video terminal 17 requests or deletes registration of position information. The transmission data section 416 stores other matters to be notified.

FIG. 5 shows the position table section 12 in FIG.
It is a figure which shows the position management information stored inside. FIG.
In, the position table unit 12 is used by the video server 11 to recognize the zone 18 in which each wireless video terminal 17 is located. The position management information stored in the position table unit 12 is created based on the control information packet 41 transmitted by the wireless video terminal 17. The position table unit 12 uses the terminal ID storage unit 51 as position management information.
And a video wireless station ID storage unit 52. The terminal ID storage unit 51 stores the identification value of the wireless video terminal 17. The video wireless station ID storage unit 52 stores the identification value of the video wireless station 15 that manages the zone 18 in which each wireless video terminal 17 is currently located.

As described above, in the wireless video communication system of this embodiment, the upstream communication path for transmitting the control information packet 41 and the downstream communication path for transmitting the video information packet 31 are completely formed. It is separated. And
A relatively wide band is allocated to the downlink communication channel transmitting the video information having a large amount of information, and a relatively narrow band is allocated to the uplink communication channel transmitting the control information having a small amount of information.

FIG. 6 shows a state in which a certain wireless video terminal 17A moves from the zone 18A to the zone 18B in the system of FIG. 1, and a certain wireless video terminal 17B receives from the zone 18B in an unreceivable area (which zone FIG. 18 is a diagram showing a situation when moving to an area that does not belong to 18). Here, the unreceivable area is an area within the terminal station controllable area 110 and incapable of receiving the menu information packet 31 and the video information packet 32 from all the video wireless stations 15.

FIG. 7 is a flowchart showing the operation of the wireless video terminal 17. FIG. 8 is a flowchart showing the operation of the control radio station 19. FIG. 9 shows the video server 11.
6 is a flowchart showing the operation of the first embodiment. FIG. 10 is a flowchart showing the operation of the video wireless station 15. Hereinafter, with reference to FIGS. 1 to 10, operations from zone movement to image information acquisition of the wireless video communication system according to the embodiment of the present invention will be described in detail.

When the video wireless station 15 receives the video information packet 32 from the video server 11 (FIG. 10; step S1000), it reads out the program menu from the menu storage section 16 of its own station (step S1001) and sends the menu information packet 31. Create (step S1002). At this time, the video / wireless station 15 searches for an empty channel among the channels 22 that can be used in the zone 18 managed by itself, and based on this search result, the menu information packet 31
The empty channel flag part 312 is set. As a result, the video wireless station 15 will now start the video information packet 3
The other unused wireless video terminal 17 cannot use the vacant channel which is about to be used for transmitting 2. Next, the video wireless station 15 sends the created menu information packet 31 and the received video information packet 32 to the zone 18
(Step S1003). At this time, the menu information packet 31 uses the channel 22 fixedly set in advance, and the video information packet 32 uses the channel 22 designated by the wireless video terminal 17 that has requested the video information. Is output to.

As the wireless video terminal 17A (see FIG. 6) located in the zone 18A moves to the zone 18B, the wireless video terminal 17A outputs a signal output by the video wireless station 15 that manages the zone 18A. Cannot be received.
Thereby, the wireless video terminal 17A recognizes that it has moved from the zone 18A (FIG. 7; step S71).
0). At this time, the wireless video terminal 17A cannot receive the menu information packet 31 from the video wireless station 15 that manages the zone 18B because the reception frequencies are not matched. This menu information packet 31 is a frequency band assigned to each video wireless station 15 as described above, and is a channel 22 fixedly set in advance.
Will be sent using. Therefore, the wireless video terminal 17
The first reception unit 171A of A adjusts the reception frequency thereof so that the menu information packet 31 from the video wireless station 15 managing the zone 18B can be received (step S).
711). The reception frequency of the first receiving unit 171A is the channel 22 from which this menu information packet 31 is transmitted.
17A, the wireless video terminal 17A will receive the menu information packet 31 (step S71).
2). The wireless video terminal 17A recognizes that it has moved to the zone 18B based on the identification value of the video wireless station 15 stored in the first video wireless station ID section 311 in the menu information packet 31. Then, the wireless video terminal 17A
A program menu is displayed on the display (not shown) (step S713).

The user carrying the wireless video terminal 17A is
By operating the input operation device (not shown) of the wireless video terminal 17A, the video information to be received is selected from the displayed program menu (step S714). Depending on,
The control unit 173 of the wireless video terminal 17A determines the channel 22 used when receiving the video information packet 32 by referring to the empty channel flag stored in the empty channel flag unit 312 (step S715). Next, the control unit 173 creates the control information packet 41, and the transmission unit 17
2 to the control wireless station 19 (step S71)
6). At this time, the control unit 173 sets the identification value of the wireless video terminal 17A in the terminal ID unit 411, the identification value of the video wireless station 15 managing the zone 18B in the second video wireless station ID unit 412, and the program number unit 413. The program number selected by the wireless video terminal 17A is stored in the used channel number section 414 as an identifier for identifying the used channel 22. Further, since the wireless video terminal 17A has moved in the zone 18, the wireless video terminal 17A stores in the position information registration flag unit 415 that the position registration is requested.
As a result, the wireless video terminal 17A is connected to the video server 1
The zone to which the current station belongs is notified to 1. Next, the control unit 173 of the wireless video terminal 17A matches the reception frequency of the first reception unit 171A with the frequency of the used channel 22 so that the video information packet 32 including the requested video information can be received (step S717). .

When the control wireless station 19 receives the control information packet 41 from the wireless video terminal 17A (FIG. 8; step S810), it determines whether the program information section 413 includes a video information request (step S810). Step S811).
When the control information packet 41 includes the video information request, the control wireless station 19 sends the control wireless station control information for confirming whether the use channel 22 stored in the control information packet 41 is usable or not to the zone. 18B is transmitted to the video wireless station 15 that manages. Note that the control wireless station control information also includes the identification value of the destination wireless video terminal 17.

Here, when a plurality of wireless video terminals 17 transmit the control information packet 41 by designating the same channel to be used at approximately the same time, the wireless video terminal 17 which later transmitted the control information packet 41 makes this designation. Channel unavailable. When the video radio station 15 receives the control radio station control information (FIG. 10; step S1010), the channel 2
The usage status of No. 2 is confirmed (step S1011). Next, the video radio station 15 sends the confirmation result to the control radio station 19
(Step S1012).

Based on the response from the video wireless station 15, the control wireless station 19 determines whether or not the channel 22 designated by the wireless video terminal 17 for acquiring the video information is an empty channel that can be used at the present time (step). S812). If this channel 22 is unavailable, the wireless video terminal 17A must newly designate the channel 22 to acquire the video information. Therefore, the control radio station 1
9 transmits control wireless station control information including a request for resetting the channel 22 to the wireless video terminal 17A (step S81).
4). On the other hand, if the channel 22 designated by the wireless video terminal 17A is available, the control wireless station 19
Transmits the received control information packet 41 to the video server 11
(Step S813).

Here, the control unit 17 of the wireless video terminal 17A
When the second receiving unit 171B receives the control wireless station control information (FIG. 7; step S710), the third receiving unit 171 recognizes that the use channel 22 is requested to be reset, and the control wireless station control information is transmitted to the own station. It is determined whether the address is addressed (step S71).
8). When addressed to its own station, the control station 173 determines that the first receiving unit 17
After releasing the frequency of the used channel set to 1A (step S719), the process returns to the operation of step S710 to re-receive the updated menu information packet 31 and determine another available empty channel. After that, the control unit 173 creates the control information packet 41, transmits it to the control wireless station 19, and waits for the video information packet 32 to be transmitted from the video wireless station 15. On the other hand, when the control wireless station control information is not addressed to itself, the control unit 173 discards the received control wireless station control information (step S720),
Returning to the operation of step S710.

Here, the method of transmitting / receiving the control radio station control information is not particularly limited, but for example, as shown in FIG.
It is also possible to allocate the same use frequency band to the control wireless station 19 and to perform wirelessly. The used frequency band assigned at this time does not overlap with the frequency band used by each video wireless station 15, and the terminal station control area 1
The transmission power is set to be larger than that of each video wireless station 15 so that the data can be transmitted to all ten. The control wireless station 19 transmits the control wireless station control information by using one predetermined channel within the allocated use frequency band.

Upon receiving the control information packet 41 (FIG. 9; step S909), the video server 11 stores the content of the control information packet 41 as history information in the history storage table section 20 (step S910). As shown in FIG. 11, the history accumulation table unit 20 has the same items as the control information packet 41, and stores all the information included in the control packet information 41. The history information stored in the history accumulation table unit 20 is referred to later,
It is used for various purposes. As an example of the usage method, a survey / statistics of the number of times of access, a total of questionnaires, etc. can be considered.

Next, the video server 11 determines whether or not the program number portion 413 of the received control information packet 41 includes a video request (step S911). When the video request is included, the video server 11 further determines whether or not the position information registration flag unit 415 includes the position registration request (step S912). When the position registration request is included, the video server 11 searches the position table unit 12 to update the position information of the wireless video terminal 17A and performs the position registration of the wireless video terminal 17A (step S913). That is, the video server 11
Uses the identification value of the wireless video terminal 17A obtained from the terminal ID section 411 of the control information packet 41 as the terminal identification value storage section 51.
Further, by storing the identification value of the video wireless station 15 obtained from the second video wireless station ID unit 412 in the video wireless station ID storage unit 52, the position information of the wireless video terminal 17 is stored in the position table unit 12. to register. Next, the video server 11 distributes the requested video information to the wireless video terminal 17A in order to deliver the requested video information to the program number section 4 of the control information packet 41.
A video information packet 32 is created based on 13 and sent to the network 13 (step S914). At this time, the video information packet 32 is transmitted using the channel 22 designated by the used channel number portion 414 of the control information packet 41 (step S922).

The video wireless station 15 receives the video information packet 32 via the video information relay unit 14 and performs the same operations as those in steps S1000 to S1003 described above. As a result, the video information packet 32 is transmitted to the wireless video terminal 17A.

The first receiver 171A of the wireless video terminal 17A
Receives the video information packet 32 (step S72
1), the control unit 173 displays the video information packet 32 on the display (not shown) (step S72).
2). After that, the wireless video terminal 17A can continuously receive the video information packet 32 from the designated channel 22. When the wireless video terminal 17A wants to acquire another video information, the menu information packet 31
Should be received and the above procedure should be repeated. At this time,
If the wireless video terminal 17A is located in the same zone 18B, the wireless video terminal 17A transmits the control information packet 41 to the control wireless station 19 without setting the position information registration flag unit 415. Therefore, the video server 11 creates the video information packet 32 and transmits it to the video wireless station 15 without performing the above-described position information update control (step S913) (step S913).
914).

Next, the operation of each section of the present wireless video communication system when the wireless video terminal 17 is located in a place that does not belong to any zone 18 will be described in detail. In FIG. 6, when the wireless video terminal 17B located in the zone 18B moves to the unreceivable area, the wireless video terminal 17B receives the menu information packet 31 output by the video wireless station 15 that manages the zone 18B. It becomes impossible to recognize the departure from the zone 18B (step S710). Next, the wireless video terminal 17
The first receiving unit 171A of B performs frequency adjustment (step S711), but cannot receive the menu information packet 31 from any of the video wireless stations 15. Thereby, the wireless video terminal 17B recognizes that it is located in the unreceivable area. Therefore, the wireless video terminal 17B
The control unit 173 of creates a control information packet 41 for requesting the video server 11 to delete the position information, and transmits the control information packet 41 to the control wireless station 19 (step S723). The control information packet 41 created at this time has the terminal ID section 411.
The identification value of the wireless video terminal 17B is stored in the position information registration flag section 415, and an instruction to request deletion of the position information of the wireless video terminal 17B registered in the position table section 12 is stored in the position information registration flag section 415.

When the control wireless station 19 receives the control information packet 41 for position registration deletion from the wireless video terminal 17B (step S810), this control information packet 4
It is confirmed that 1 includes a location registration deletion request (step S815). Next, the control radio station 19 uses the network 1
3 to the video server 11 via the control information packet 41
Is transmitted (step S816).

The video server 11 receives the control information packet 41 from the control wireless station 19 (step S90).
9) After storing the content in the history storage table section 20 (step S910), the program number section 413 and the position information registration flag section 415 of the control information packet 41 are checked, and this control information packet 41 requests the position information deletion. ,
That is, it is determined whether the request is related to the out-of-service processing request or the video information request (step S91).
1). When the position information registration flag unit 415 stores information indicating that the position information is deleted, the video server 11
Searches the position table section 12 and finds this wireless video terminal 1
The position registration information registered for 7B is deleted (step S915). As a result, the video server 1
1 can manage the wireless video terminal 17 even if the wireless video terminal 17 is located in the unreceivable area. If the wireless video terminal 17 moves to the unreceivable area while receiving the video information packet 32 in the zone 18 in which it was previously located, the subsequent transmission of the video information packet 32 becomes useless. As described above, the video server 11 recognizes that the wireless video terminal 17 is located in the unreceivable area, so that the video information packet 3
2 transmission can be stopped, and useless transmission can be eliminated. When the wireless video terminal 17 moves to any zone 18 again, each unit of the present wireless video system performs the same operation as described above. Step S9 above
After 15, the video server 11 sends a still image transmission instruction,
It transmits to the control radio station 19 via the network 13 (step S916).

When the control wireless station 19 receives a still image transmission instruction from the video server 11 (step S808),
The still image information (previously held in the control wireless station 19) is transmitted to the wireless video terminal 17B that has moved outside the zone 18B (step S809). Various contents can be considered as the still image transmitted at this time. For example,
When the present wireless video communication system is used in museums and museums, the contents of the exhibitions currently held in these museums are included in still images. When the present wireless video communication system is used in a theme park, a map of the park and the like are included in the still image. In addition, the contents included in the still image may be variously developed depending on the operation of the system.

When each wireless video terminal 17 enters the zone 110 of the control wireless station 19, it immediately establishes a communication link with the wireless control station 19. This link may be established using a separate frequency for each wireless video terminal 17, or one frequency may be time-divided into a plurality of slots and established using each slot. In any case, a link is established between the wireless video terminals 17 without interference. In step S809, the still image is transmitted from the control wireless station 19 to the wireless video terminal 17 using this link. Therefore, for example, the wireless video terminal 17B that has moved to the outside of the zone 18B individually receives the still image service from the control wireless station 19.

The wireless video terminal 17, which has received the still image information from the control wireless station 19, displays the still image on a display (not shown). As a result, the user can
Even if the user moves to a position that does not belong to the above, some kind of information provision can be received from the system.

In the above embodiment, the video server 11
Although the control wireless station 19 is provided separately from the above, the function of the control wireless station 19 can be included in the video server 11.
In this case, the video server 11 functions as a center device having a function of processing a video request and a channel setting instruction from each wireless video terminal 17, and a function of supplying the requested video, and the center device and each wireless device. Video terminal 17
The control information packet 41 is directly transmitted and received between and.

FIG. 12 is a block diagram showing the overall structure of a wireless video communication system according to the second embodiment of the present invention. In order to simplify the illustration, FIG. 12 shows the video server 11, the position table unit 12, the video information relay unit 14, the video wireless station 15, the menu storage unit 16, and the history storage table in FIG. Although the unit 20 is not shown, this embodiment has all of these configurations. Further, the present embodiment includes a plurality of control wireless stations 19, and accordingly, a plurality of sets of the video information relay unit 14, the video wireless station 15, and the menu storage unit 16. In addition, the present embodiment includes a control device 7 in addition to the configuration of FIG. The control device 7 creates terminal station control information for controlling all the wireless video terminals 17 in the wireless video communication system. In addition, the control device 7 performs other than the distribution of the video information (for example, turning on the power of the wireless video terminal 17
Off, etc.) are controlled.

Each control wireless station 19 has its own terminal station control area 110 which does not overlap with each other, and the wireless video terminal 1 located in the terminal station control area 110.
It receives the control information packet 41 from the control device 7 and transmits the control information packet 41 to the control device 7. Here, the control wireless station 19 must determine whether to transmit the control information packet 41 to the control device 7 or the video server 11. Therefore, the control wireless station 19 transmits the control information packet 41 to the control device 7 only when the transmission data unit 416 stores the information. In addition, when transmitting to the video server 11, it is as above-mentioned.
Further, the control wireless station 19 transmits the terminal station control information transmitted from the control device 7 to the wireless video terminal 17. The wireless video terminal 17 performs processing according to the content of the received terminal station control information. In addition, the wireless video terminal 17 includes the control device 7
When there is a control request, the control request is stored in the transmission data section 416 of the control information packet 41 created by the own station and transmitted. The terminal station control information transmitted from the control device 7 includes not only control information for a specific wireless video terminal 17 but also control information for all wireless video terminals 17 located in the terminal station control area 110. included.

The operation of the wireless video communication system shown in FIG. 12 will be described below. The control device 7 transmits the terminal station control information including the setting of the shared identification value as necessary so that the terminal station control information for all the wireless video terminals 17 located in the terminal station control area 110 can be transmitted. , To the control radio station 19. The control wireless station 19 transmits the terminal station control information to the terminal station control area 110 managed by the control wireless station 19. The second receiving unit 171B of the wireless video terminal 17 located in the terminal station control area 110 receives the terminal station control information. And the wireless video terminal 1
When the control unit 173 of 7 recognizes the shared identification value, the wireless video terminal 17 is assigned the shared identification value in addition to the unique identification value. As a result, the control device 7 has grouped all the wireless video terminals 17 located in the terminal station control area 110.

As described above, even if the wireless video terminal 17 to which the shared identification value is assigned is located in another zone 18 within the terminal station control area 110, the controlling wireless station 1
9 can control the wireless video terminal 17 by transmitting the terminal station control information including the shared identification value. by this,
When it is necessary to collectively control the grouped wireless video terminals 17 (for example, turning on / off the power of the wireless video terminals 17), the terminal station control information including individual identification values is not collectively transmitted. Then, the wireless video terminal 17 can be controlled. Further, since the wireless video terminal 17 includes two receiving units, it is possible to receive the terminal station control information without hindering the reception of the video information packet 32.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a wireless video communication system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a frequency spectrum of information distributed from a video wireless station 15 to a wireless video terminal 17 in the wireless video communication system shown in FIG.

3 is a diagram showing a frame structure of information distributed from a video wireless station 15 to a wireless video terminal 17 in the wireless video communication system shown in FIG.

4 is a diagram showing a frame structure of information transmitted from a wireless video terminal 17 to a control wireless station 19 in the wireless video communication system shown in FIG.

5 is a diagram showing position registration information stored in a position table section 12 in the wireless video communication system shown in FIG.

6 is a diagram showing how the wireless video terminal moves in the wireless video communication system shown in FIG. 1. FIG.

7 is a flowchart showing the operation of the wireless video terminal in the wireless video communication system shown in FIG.

8 is a flowchart showing an operation of a control wireless station in the wireless video communication system shown in FIG.

9 is a flowchart showing the operation of the video server in the wireless video communication system shown in FIG.

10 is a diagram showing the wireless video communication system shown in FIG.
It is a flowchart which shows operation | movement of a video wireless station.

11 is a diagram showing the wireless video communication system shown in FIG.
5 is a diagram showing history information stored in a history storage table section 20. FIG.

FIG. 12 is a diagram showing a configuration of a wireless video communication system according to a second example of the present invention.

FIG. 13 is a diagram showing a conventional wireless video communication system.

[Explanation of symbols]

 11 ... Video server 12 ... Position table section 13 ... Network 14 ... Video information relay section 15 ... Video radio station 16 ... Program menu section 17 ... Wireless video terminal 18 ... Zone 19 ... Control radio station 110 ... Terminal station control area 31 ... Menu Information packet 32 ... Video information packet 41 ... Control information packet 51 ... Terminal ID storage 52 ... Video wireless station ID storage 7 ... Control device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Wada 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Tanabe Takumi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (12)

[Claims] 1. A wireless video communication system for wirelessly distributing various video information to a mobile terminal station, the video server storing a plurality of types of video information, and the video via a network. A video wireless station connected to the server and transmitting video information supplied from the video server to the terminal station via a first wireless communication path, and a video wireless station transmitted from the terminal station via a second wireless communication path. A control wireless station for receiving the incoming control information and notifying the video server, wherein the terminal station transmits the control information,
Informing that video information is requested and the type of video information requested, the video server searches for corresponding video information based on the control information received from the control wireless station, and outputs the video information on the network, A relatively wide band is allocated to the first wireless communication path, and a relatively narrow band is allocated to the second wireless communication path. 2. The video radio station can use a plurality of communication channels in the first radio communication channel to transmit video information, and the terminal station transmits the control information. By
Further, a communication channel for receiving video information is designated, the video wireless station monitors the current usage status of the communication channel, and the control wireless station is designated by the control information when receiving the control information. Inquiring to the video wireless station as to whether a communication channel is available, transmitting control information to the video server if available, requesting resetting of the receiving communication channel to the terminal station if not available, The wireless video communication system according to claim 1, wherein the video wireless station transmits the video information supplied from the video server to the terminal station using a communication channel designated by the terminal station. 3. A plurality of the video radio stations are installed and each has a unique radio zone in which each of them can communicate, and the control radio station covers the radio zones of all the video radio stations. The wireless video communication system according to claim 1, wherein the wireless video communication system is capable of performing communication within an area. 4. A frequency band that does not overlap with each other is fixedly allocated to each of the video wireless stations as the first wireless communication path, and each of the video wireless stations has a frequency that is fixedly allocated. The wireless video communication system according to claim 3, wherein the video information is transmitted using a plurality of communication channels obtained by dividing the band. 5. A menu storage unit that is connected to each of the video radio stations and stores title information of the video information stored in the video server is further provided, and each of the video radio stations is stored in the menu storage unit. The menu information created based on the displayed title information, the identification value assigned to each video wireless station, and the usage status of the communication channel in the first wireless communication path, To the wireless zone of its own station using a predetermined communication channel in the, the terminal station creates the control information by referring to the received menu information, the identification value and the use status of the communication channel The wireless video communication system according to claim 4, wherein 6. The control information includes at least a video information number part storing an identification value for specifying video information requested to be delivered to the video server, and a terminal storing an identification value unique to the terminal station. A station ID section, a first transmitting / receiving station ID section that stores an identification value of the video wireless station that has transmitted the menu information, and a use channel specifying section that specifies a communication channel for receiving requested video information, The control wireless station inquires of the video wireless station having the identification value stored in the first transmitting / receiving station ID section whether or not the communication channel stored in the use channel designating section is usable, If the channel cannot be used, the terminal station I
The terminal station having the identification value stored in the D section is requested to reset the communication channel, and when the communication channel can be used, the control information is transferred to the video server, and the video server transfers The wireless video communication system according to claim 5, wherein the corresponding video information is searched for by referring to the video information number portion of the control information that has been received, and is output on the network. 7. Position information for storing the identification value of the terminal station and the identification value of the video station included in the control information received from the control station by the video server, as information indicating the current location of the terminal station. 7. The storage device further comprising storage means.
The wireless video communication system according to. 8. The control information further includes a position information registration flag portion for notifying the video server whether registration of the position information stored in the position information storage means is requested or deleted. 8. The wireless video communication system according to claim 7, wherein the video server changes the content of the position information storage means with reference to the position information registration flag part of the received control information. 9. The video server, based on the position information registration flag portion included in the received control information,
9. The wireless video communication system according to claim 8, wherein when recognizing that the terminal station is not located in any zone, the position information of the terminal station is deleted from the position information storage means. 10. The wireless video communication system according to claim 1, further comprising history information storage means for storing history of control information received by the video server as history information. 11. A plurality of the control radio stations are provided, each of which has its own communicable area, and creates terminal station control information for controlling each of the terminal stations. Further comprising a control device for transmitting the terminal station control information via the control radio station, the control device, by using the terminal station control information to give the same shared identification value to each terminal station, The wireless video communication system according to claim 1, wherein all the terminal stations located within the communicable area of the control wireless station are collectively controlled. 12. The terminal station control information stores an identification value storage unit for storing an identification value unique to each terminal station or the shared identification value, and data for controlling each terminal station. And a data storage unit, wherein the control device uses terminal station control information including an identification value unique to each terminal station,
Each terminal station is individually controlled, and all terminal stations located within the communicable area of all controlled radio stations are collectively controlled by using the terminal station control information including the shared identification value. The wireless video communication system according to claim 11.