JP2010141625A - Radio transmitting system, radio base station apparatus, and communication channel selecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio transmitting system, a radio base station apparatus, and a communication channel selecting method for stably transmitting real time data such as image/audio data, etc. and also maintaining higher transmission rate in transmission for non-real time data even in the environment where interference by radar is generated. <P>SOLUTION: The radio transmitting system can transmit data between the radio base station apparatus and radio terminals via a communication path including a first selectable communication channel that is included in the predetermined radio frequency band and is shifted to the other channel upon detection of the radiowave to the relevant channel and a second selectable communication channel not included in the predetermined radio frequency band. The radio transmitting system includes a data determining unit 206 for determining whether the data is real time data or non-real time data and a communication channel selecting unit 205 for selecting the communication channel for transmitting data from the first selectable communication channel or the second selectable communication channel based on the result of determination by the data determining unit 206. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radio transmission system, a radio base station apparatus, and a communication channel selection method using a communication channel that may interfere with a radar wave, and in particular, movie content in a passenger accommodation area of a transport system such as a passenger aircraft or a train. The present invention relates to a radio transmission system, a radio base station apparatus, and a communication channel selection method suitable for providing a video / audio information distribution service.

  Services for distributing entertainment content such as music and movies to each seat in passenger aircraft and train transportation systems are widespread. Conventionally, these services were transmitted by wired cables laid in the passenger accommodation area in the transport system, but from the viewpoint of weight reduction of the system and flexibility in changing seat layout, replacement with a wireless transmission system has been considered. Yes.

  As a wireless transmission system suitable for such a use, there is a wireless LAN system such as IEEE802.11a / b / g / n. Wireless LAN systems are already widely used in enterprises and general households, and have a track record as systems capable of relatively stably realizing high-speed data communication of several tens of Mbps or more. In particular, IEEE802.11a / n uses 5 GHz band radio waves, so there is little interference with other systems, and it is fast at a physical layer transmission speed of 50 Mbps or more in IEEE802.11a and 300 Mbps or more in IEEE802.11n. Data communication can be performed stably. Further, as described above, since the device is widely used, the device price is relatively low.

  However, this 5 GHz band is partly shared with the frequency for weather radar (hereinafter simply referred to as “radar”), so that in areas where the radar is operated, the wireless LAN radio waves do not adversely affect the radar, or It is necessary to select a communication channel so that the wireless LAN is not affected by radar wave interference.

  For this reason, the wireless LAN device incorporates a DFS (Dynamic Frequency Selection) function that dynamically changes the communication channel. When the wireless LAN device detects a radar wave, communication is performed avoiding the communication candidate channel of that frequency. The channel is selected. Radar wave detection is performed not only when the wireless LAN is activated, but also during operation. When a radar wave is detected during the operation, the communication channel is immediately changed.

  FIG. 6 is a diagram showing a frequency map showing the wireless communication channel of IEEE802.11a in Japan. As shown in FIG. 6, eight communication candidate channels having a center frequency from 5.18 GHz to 5.32 GHz every 20 MHz are prepared in a band of 200 MHz from 5.15 to 5.35 GHz. Among these, since 5.25 to 5.35 GHz is used for radar, four communication candidate channels of 5.26 to 5.32 GHz may interfere with radar waves. The wireless LAN device can detect this interference by DFS, select a communication candidate channel having no problem, and continue communication.

  However, when the information to be communicated is real-time data that requires simultaneity (real-time performance) such as video and audio during streaming, data transmission is temporarily interrupted when the communication channel is changed by DFS. Therefore, there has been a problem that the reproduced video / audio is temporarily interrupted or a transient noise is generated.

  Therefore, conventionally, a method has been proposed in which communication is performed while avoiding the use of communication candidate channels in a frequency band shared with the radar in an area where the radar is operated (see, for example, Patent Document 1). Once the geographical location where the wireless LAN device is installed is determined, it is possible to know in advance whether or not the radar is operating in the vicinity of the area. Is operating.

If all the radar operation information in Japan is stored in advance in the storage means in the wireless LAN device, the possibility of interference can be determined in advance by inputting the geographical location information where the wireless LAN device is installed is doing. As a result, when operating the wireless LAN in an area where interference with the radar can be predicted in advance, only the communication candidate channels outside the radar frequency band are used, so that real-time data can be stably transmitted.
JP 2007-53726 A

  As described above, in the method of Patent Document 1, the possibility of interference with the radar is estimated in advance based on the radar operation information and the installation position information of the wireless LAN device, and selection of communication candidate channels existing within the frequency shared with the radar is selected. By prohibiting, it becomes possible to transmit video and audio information that requires simultaneity without interruption. However, the method of Patent Document 1 has the following two problems.

  First, information to be wirelessly transmitted is not limited to video / audio information that requires simultaneity. Even if the video / audio information is not a streaming type but a download type, and the downloaded one can be reproduced and viewed stably from a hard disk or the like, the temporary interruption at the time of download is not a big problem. Rather, it is desirable that the average transmission rate be high in order to download in a short time. It goes without saying that control information that is not video / audio information, e-mails, still images, Web screens, etc. have no problem with temporary interruption of transmission, and that the average transmission speed is important. Thus, it is important to transmit non-real time data that does not require simultaneity as fast as possible.

  If the use of communication candidate channels in the radar frequency band is restricted in advance as in the method of Patent Document 1, only the remaining communication candidate channels are used simultaneously by a plurality of wireless LAN devices. The average transmission speed per unit is greatly reduced. This problem becomes a problem not only when a plurality of wireless access points are used in the system, but also when there are wireless access points of other systems in the vicinity of the system.

  Movie content data such as movies in the in-flight entertainment system of a passenger aircraft may be downloaded in advance from a wireless base station device to a wireless terminal device while parked at a ground airport. In the airport environment, since the probability of radar operation is high, it is assumed that the download must be executed at a low speed only in a part of all the communication candidate channels as described above. In addition, when using frequency hopping technology with meteorological satellites, etc., it is mandatory to implement DFS because one satellite uses multiple channels of the wireless LAN by dynamically changing the frequency. There are cases where a large number of channels cannot be used. In the case of IEEE802.11a shown in FIG. 6, a communication channel is selected and used only from four communication candidate channels out of eight communication candidate channels.

  Secondly, the position of a transport aircraft such as a passenger aircraft changes every moment. Therefore, it is complicated and difficult to input geographical position information that is not a problem with a fixed stationary wireless LAN device as assumed in Patent Document 1. It is practically impossible for a user to input his / her position information that changes every moment, and a system that automatically updates position information using, for example, GPS is required. As a result, the scale and price of the system increases. In addition, because aircraft change the route complicatedly due to the influence of weather conditions etc., even if the position of the aircraft can be grasped by GPS, it is not possible to grasp the influence of radar at all points on the earth and register it in the database Virtually impossible.

  In addition, as a result of updating the location information in this way, the communication channel that was available until immediately before can no longer be used suddenly due to interference with the radar in the new destination area without interrupting the video and audio information The original purpose of transmission cannot be realized.

  The present invention has been made to solve such problems, and can stably transmit real-time data such as video / audio information that requires simultaneity even in an environment where interference with radar exists, and at the same time. An object of the present invention is to provide a radio transmission system, a radio base station apparatus, and a communication channel selection method that can transmit non-real-time data that does not require high-speed performance while maintaining high speed.

  In order to achieve the above object, a wireless transmission system of the present invention includes a first communication candidate channel that is included in a predetermined radio frequency band and shifts to another channel when a radio wave of the channel is detected, and a predetermined radio frequency. A wireless transmission system for transmitting data between a wireless base station device and a wireless terminal device via a communication channel having a second communication candidate channel not included in a band, wherein the data is real-time data or non-real-time Based on the determination result of the data determination means for determining whether it is data, the radio wave detection means for detecting the radio wave of the first communication candidate channel, and the data determination means, the first communication candidate channel or the second communication candidate channel And a communication channel selection means for selecting a communication channel for transmitting data from the inside.

  Accordingly, an appropriate communication channel can be selected from the communication candidate channels depending on whether the data to be transmitted is real-time data or non-real-time data. Therefore, the communication path can be used efficiently. Furthermore, it is not necessary to have a database of radars that can be detected at each location where the device is installed. In addition, even in a moving body such as an aircraft, it is not necessary for the user to input his / her position information that changes every moment, or to acquire from GPS or the like and perform complicated calculation processing. You can build a system.

  In the wireless transmission system of the present invention, when the data determining unit determines that the data is real-time data, the communication channel selecting unit may select a communication channel from the second communication candidate channels.

  As a result, real-time data such as video / audio information during streaming requiring simultaneity can be stably and wirelessly transmitted.

  In the wireless transmission system of the present invention, when the data determination unit determines that the data is non-real time data, the communication channel selection unit determines whether the first communication candidate channel or the communication channel is based on the detection result of the radio wave detection unit. A communication channel may be selected from the second communication candidate channels.

  As a result, in wireless transmission of non-real-time data such as control information that does not require simultaneity and video / audio information at the time of download, transmission is performed while maintaining a high average transmission rate without reducing the number of communication candidate channels. Can do.

  In the wireless transmission system of the present invention, the communication channel selection means may preferentially select a communication channel from the first communication candidate channels.

  Thereby, since the communication candidate channel allocated to the real-time data is not used for the transmission of the non-real-time data, the real-time data can be transmitted more stably.

  In the radio transmission system of the present invention, the predetermined radio frequency band may be a radar radio frequency band.

  As a result, even in an environment affected by radar waves, real-time data can be stably and wirelessly transmitted without interruption.

  In the wireless transmission system of the present invention, the wireless base station device and the wireless terminal device may be installed in a passenger accommodation area of a transportation facility.

  As a result, even when a transport such as a passenger aircraft passes through a place affected by radar waves during operation, real-time data can be wirelessly transmitted stably and without interruption. Therefore, high-quality video and audio content can be provided to passengers in the passenger aircraft entertainment service.

  The radio base station apparatus according to the present invention includes a first communication candidate channel that is included in a predetermined radio frequency band and shifts to another channel when a radio wave of the channel is detected, and a second that is not included in the predetermined radio frequency band. A radio base station apparatus for transmitting data to a radio terminal apparatus via a communication channel having a communication candidate channel, a radio wave detection means for detecting a radio wave of the first communication candidate channel, and whether the data is real-time data Communication channel selection means for selecting a communication channel for transmitting data from the first communication candidate channel or the second communication candidate channel according to whether the data is non-real-time data.

  In the radio base station apparatus of the present invention, when the data is real-time data, the communication channel selection means may select a communication channel from the second communication candidate channels.

  In the radio base station apparatus of the present invention, when the data is non-real-time data, the communication channel selection means can select the first communication candidate channel or the second communication candidate channel based on the detection result of the radio wave detection means. A communication channel may be selected from the list.

  In the radio base station apparatus of the present invention, the communication channel selection means may preferentially select a communication channel from the first communication candidate channels.

  In the radio base station apparatus of the present invention, the predetermined radio frequency band may be a radar radio frequency band.

  Moreover, the radio base station apparatus of the present invention may be installed in a passenger accommodation area of a transportation facility.

  The communication channel selection method of the present invention includes a first communication candidate channel that is included in a predetermined radio frequency band and that shifts to another channel when a radio wave of the channel is detected, and a second that is not included in the predetermined radio frequency band. A communication channel selection method for transmitting data between a wireless base station device and a wireless terminal device via a communication channel having a communication candidate channel, and determining whether the data is real-time data or non-real-time data And a communication channel selection step of selecting a communication channel for transmitting data from the first communication candidate channel or the second communication candidate channel based on the determination result in the data determination step. It is characterized by that.

  In the communication channel selection method of the present invention, when the data determination step determines that the data is real-time data, the communication channel selection step may select a communication channel from the second communication candidate channels. .

  In the communication channel selection method of the present invention, when it is determined in the data determination step that the data is non-real-time data, the communication channel selection step selects the first communication candidate channel or the second communication candidate channel. A communication channel may be selected.

  In the communication channel selection method of the present invention, the communication channel selection step may preferentially select a communication channel from among the first communication candidate channels.

  According to the present invention, even in an environment where there is interference with a radar, real-time data such as video / audio information that requires simultaneity can be stably transmitted, and high-speed can be used for non-real-time data that does not require simultaneity. It is possible to provide a radio transmission system, a radio base station apparatus, and a communication channel selection method that can be transmitted while maintaining reliability.

  According to the present invention, when data is transmitted from a radio base station apparatus to a radio terminal apparatus, real-time data such as video / audio information that requires synchronization is not a communication candidate channel (no DFS function). Select a communication channel from (communication candidate channels), and non-real-time data that does not require simultaneity will be selected from all communication candidate channels, including communication channels that may interfere with radar (communication channels with DFS function). Select a communication candidate channel that does not interfere with. As a result, real-time data can be transmitted stably without interruption during transmission, and non-real-time data can be transmitted while maintaining high speed.

  Hereinafter, a wireless transmission system according to an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
First, a wireless transmission system according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a basic configuration of a video / audio information distribution system to which a wireless transmission system according to the present embodiment is applied. Content to be distributed such as moving image content and music content is stored in the content server 101. The accumulated content is wirelessly transmitted to the wireless terminal devices 104 and 105 and the wireless terminal device 106 via the wireless base station device 103. The number of wireless terminal devices is three for convenience of explanation. However, the number of wireless terminal devices is not particularly limited, and may be set according to the form and scale of the usage system.

  In a large transport such as a large passenger aircraft, it may be difficult to cover the whole area of a passenger cabin with a single radio base station apparatus. Therefore, a system comprising the radio base station apparatus 103 and radio terminal apparatuses 104 to 106 You may install two or more.

  The radio base station apparatus 103 is connected to an external network 102 such as the Internet as necessary. As a result, the wireless terminal devices 104 to 106 can connect to the WEB site to acquire information and send and receive e-mails.

  A configuration in which a plurality of radio base station apparatuses 103 are installed and used separately for real-time data and non-real-time data is also conceivable.

  FIG. 2 is a block diagram showing a configuration of a part related to communication channel selection of radio base station apparatus 103 used in the radio transmission system according to the present embodiment.

  Transmission data to be transmitted to the wireless terminal devices 104 to 106 is first stored in a predetermined frame format by the frame processing unit 201, digital carrier wave modulated by the modulation unit 202, and further converted to an appropriate transmission frequency by the transmission unit 203. After being amplified, it is transmitted as an RF signal in the air. Note that OFDM, BPSK, QPSK, 16QAM, etc. are used as digital carrier wave modulation in a wireless LAN.

  On the other hand, whether the transmission data is real-time data that requires simultaneity such as video / audio information during streaming, or non-real-time data that does not require simultaneity such as control information or video / audio information during download The determination is performed by the unit 206, and the determination result is input to the communication channel selection unit 205 as concurrency identification information. For example, the content server 101 may transmit concurrency identification information for each content and transmit data. Alternatively, a method of transmitting simultaneity identification information with a command in advance for each content may be used. The addition of the concurrency identification information can be manually written in advance by the user in advance according to the contents and usage method of each content. Alternatively, the content server or the like can be automatically assigned according to the content attribute (for example, file extension). Further, the radar wave detection unit 204 detects whether or not an operating radar exists in the vicinity of the radio base station apparatus 103, and the detection result is input to the communication channel selection unit 205.

  A communication channel selection unit (communication channel selection unit) 205 receives the synchronization identification information that is the determination result from the data determination unit (data determination unit) 206 and the radar wave detection result of the radar wave detection unit (radio wave detection unit) 204. The communication channel with the wireless terminal devices 104 to 106 is selected from the first and second communication candidate channels. Here, the first communication candidate channel is a communication candidate channel that is included in a radio frequency band used for radar and that shifts to another channel by the DFS function when a radar wave is detected. A channel is a communication candidate channel that is not included in the radio frequency band used for radar.

  First, when the simultaneity identification information indicates “simultaneity unnecessary”, all communication candidate channels are selected. In the case of FIG. 6, all eight channels are candidates. Under that condition, if there is a communication candidate channel that interferes with the radar wave based on the radar wave detection result, the communication channel is selected avoiding that channel.

  Next, when the simultaneity identification information represents “simultaneity is necessary”, the communication channel selection unit 205 selects a communication candidate channel (second communication candidate channel) outside the radar frequency band as a communication channel selection candidate. To. In the case of FIG. 6, one of the four communication candidate channels of 5.18 to 5.24 GHz is selected. In this case, even if the radar wave is not detected by the radar wave detection unit 204, the communication candidate channel (first communication candidate channel) in the radar frequency band is not selected. When communication candidate channels within the radar frequency band are used, communication is performed using the DFS function when radar operation is started during transmission of video and audio information, or when radar is newly detected due to movement of an aircraft, etc. This is because the channel needs to be changed, and transmission of video / audio information is interrupted.

  In the above description, the data determination unit 206 is included in the radio base station device 103. However, the data determination unit 206 is a content server 101 installed outside the radio base station device 103, a control device that controls the entire system, or the like. (Not shown) may be provided. In this case, the communication channel selection unit 205 directly receives the synchronization identification information from the outside.

  As a specific example, when the data determination unit 206 is provided in the content server 101, the content server 101 can identify whether the data to be transmitted is real-time or non-real-time. Is transmitted to the communication channel selection unit 205 inside the radio base station apparatus 103 via the communication path. Not only this example but various deformation | transformation are possible.

  In general, the communication channel selection unit 205 is mounted in a wireless chip internal or external CPU. Therefore, the CPU receives the radar wave detection unit 204 and the synchronization identification information as input, and the transmission unit 203 should transmit. The channel is selected. Such various mounting methods are possible.

  FIG. 3 is a flowchart showing an operation procedure of the wireless transmission system according to the present embodiment. In FIG. 3, the communication channel selection unit 205 reads the synchronization identification information of the transmission data in step S101, and determines whether or not the transmission data requires synchronization in step S102. If it is determined in step S102 that the information requires simultaneity (in the case of “YES”), it is actually used from the communication candidate channels (second communication candidate channels) outside the radar frequency band in step S103. Select the communication channel to be used.

  On the other hand, if it is determined in step S102 that the information does not require simultaneity (in the case of “NO”), the process proceeds to step S104, and the radar wave detection unit 204 reads the radar wave detection result. After that, in step S105, the communication channel selection unit 205 uses the communication channel actually used from the communication candidate channels excluding the communication candidate channel having the radar wave interference detected in step S104 among all the wireless communication channels. Select.

  When the communication channel is selected by the above operation and transmission data is transmitted, the next transmission data is waited in step S106. Note that when the simultaneity identification information is transmitted to the radio base station apparatus 103 in advance by a command, the processes of step S101 and step S102 may be executed at least once. That is, if the information requires simultaneity, the process of step S103 is executed. If the information does not require simultaneity, the processes of step S104 and step S105 are repeated. At this time, the process of step S106 is skipped.

  Also, since the DFS function (not shown in FIG. 3) by the radar wave detection unit 204 is normally operating, the communication channel selected in step S105 is the communication candidate channel (the first channel in the radar frequency band). In the case of 1 communication candidate channel), when interference with a radar wave is detected by the DFS function, movement to another communication candidate channel within the radar frequency band or communication outside the radar frequency band It is possible to move to a candidate channel.

  In this embodiment, all channels are selected for non-real time information. However, for example, when the amount of non-real time information is small, a channel affected by DFS may be selected in advance. .

(Second Embodiment)
Next, a radio transmission system according to the second embodiment of the present invention will be described with reference to the flowchart showing the operation procedure of FIG. In the flowchart of FIG. 4, the same operation steps as those in the flowchart of FIG. In FIG. 4, when the synchronization identification information of the transmission data needs to be synchronized (in the case of “YES” in step S102), the communication channel is changed along the steps S101 to S103 as in the case of FIG. A communication candidate channel (second communication candidate channel) outside the radar frequency band is selected. On the other hand, when the simultaneity identification information does not need simultaneity (in the case of “NO” in step S102), the communication channel selection unit 205 reads the radar wave detection result from the radar wave detection unit 204 in step S104. In step S107, it is detected whether there is a communication candidate channel that can be used within the radar frequency band.

  As shown in FIG. 6, in the case of the 5 GHz band, four communication candidate channels (first communication candidate channels) are included in the radar frequency band, and one of them has an interference relationship with the radar wave. However, the remaining three are available. When it is determined in step S107 that there is a communication candidate channel that can be used (in the case of “YES”), the process proceeds to step S108 to select a communication channel from communication candidate channels that do not have radar wave interference in the radar frequency band. Do.

  If it is determined in step S107 that all communication candidate channels in the radar frequency band interfere with the radar wave, that is, there is no communication candidate channel available (in the case of “NO”), the process proceeds to step S109. To do. In step S109, the communication channel selection unit 205 selects a communication channel from a communication candidate channel (second communication candidate channel) outside the radar frequency band.

  As a result, when the transmission data does not require simultaneity, the communication channel selection unit 205 first gives priority to the selection of the communication candidate channel (first communication candidate channel) in the radar frequency band. Therefore, it is possible to preserve a communication candidate channel (second communication candidate channel) outside the radar frequency band used in the case of video / audio information that requires high performance.

  Even if the communication candidate channel in the radar frequency band is selected as the communication channel in step S108, if the radar wave detection unit 204 detects a radar wave that interferes with the communication channel from the middle, the DFS is detected. According to the function, the communication channel is selected from other communication candidate channels in the radar frequency band. At this time, wireless transmission is interrupted, but in this embodiment, transmission data that needs to be synchronized is not sent to a communication channel that may be interrupted. It does not occur.

  Note that when the synchronization identification information is transmitted to the radio base station apparatus 103 in advance by a command, the processing is the same as in the first embodiment, except that Steps S107, S108, and S109 are added. It is a point.

  FIG. 5 shows a configuration example when the wireless transmission system according to the embodiment of the present invention is installed and used in a transporting organization such as a passenger aircraft. Screen display units 311 to 313 and sound reproducing headsets 321 to 323 are attached to the passenger seats 301 to 303. That is, each passenger views the video / audio information through the screen display units 311 to 313 and the audio reproduction headsets 321 to 323. A wireless access point 330 is installed on the side wall or ceiling of the passenger accommodation area, and is connected to the content server 101 and other wireless access points by a wired cable 331.

  At this time, the wireless access point 330 is a wireless base station device 103 itself or a wireless transmission / reception unit mainly composed of the wireless base station device 103, and communicates with a plurality of wireless terminal devices 104 to 106.

  The screen display units 311 to 313 are thin display devices using, for example, a liquid crystal display, and are attached to the backs of the backrests of the passenger seats 301 to 303. The screen display units 311 to 313 incorporate wireless terminal devices 104 to 106, respectively, and receive and display various contents transmitted from the wireless access point 330.

  The audio reproduction headsets 321 to 323 are used as stereo headphones for audio information among the video and audio information received by the wireless terminal devices 104 to 106.

  Large passenger aircraft, train vehicles, and the like have a large number of seats of several hundred or more, and therefore it is general to prepare a plurality of sets of configurations as shown in FIG. 5 to cover all seats.

  In the above description, the wireless terminal devices 104 to 106 are built in the screen display units 311 to 313. However, the wireless terminal devices 104 to 106 are built in their own housings, and video signals are transmitted from the housings to the screen display units 311 to 311. It is good also as a structure which outputs audio | voice information to each audio | voice reproduction | regeneration headset 321-323 to 313.

  As described above, according to the wireless transmission system of the embodiment of the present invention, real-time data such as video / audio information that requires simultaneity is a communication candidate channel (no DFS function) that has no possibility of interfering with radar. Select a communication channel from (communication candidate channels), and non-real-time data that does not require simultaneity will be selected from all communication candidate channels, including communication channels that may interfere with radar (communication channels with DFS function). Select a communication candidate channel that does not interfere with. As a result, real-time data such as video / audio information during streaming can be transmitted stably without interruption during transmission, and non-real-time data such as video / audio information during download can be transmitted while maintaining high speed. Can do.

  In addition, it is not necessary to have a radar database that can be detected at each location where the device is installed. Since ground exploration satellites and meteorological satellites move and change the transmission direction in time toward the earth, the conventional method makes the database large and complex. Therefore, the ability to omit the work of creating this database is a great advantage for the system. In addition, it is not necessary for the user to input his / her position information that changes every moment in a moving body such as an aircraft, or to obtain complicated information from GPS or the like. Thereby, a small-scale and low-cost system can be constructed.

  Further, by assigning a communication channel having a DFS function to a non-real time data communication channel preferentially, the communication candidate channel assigned to the real time data is not used for the non real time data transmission. Can be performed.

  In the above-described embodiment, the video terminal information from the content server 101 and the information from the external network 102 such as the WEB screen and e-mail are time-divisionally transmitted from the same wireless base station device 103 (wireless access point 330) to the wireless terminal device. Although described as transmitting to 104 to 106, different radio base station apparatuses may be used depending on the type of information.

  In the above embodiment, the case where the channel (frequency) to be used is changed due to the influence of the radar is taken as an example, but it is obvious that the effect unique to the present invention can be obtained even when the channel is changed by other than the radar. And therefore are not excluded from the scope of the present invention.

  Moreover, although the example which determines the frequency to be used for each individual radio base station apparatus 103 has been described in the above embodiment, when a plurality of radio base station apparatuses are installed, each radio base station as a whole system The frequency used by the device may be determined. As a specific example, the radar detection information is aggregated in the content server 101, the content server 101 determines the frequency used by each radio base station device 103 as a whole system, and sends a command or the like to each radio base station device 103. An instruction may be sent.

  In the above embodiment, an aircraft is used as an example. However, the present invention is not limited to this, and the detected radar changes with time even at a stationary position. Therefore, the radar is not limited to a moving object such as an aircraft. In all cases where it can be detected, the present invention is effective and therefore not excluded from the scope of the present invention.

  INDUSTRIAL APPLICABILITY The present invention is useful for a wireless transmission system, a wireless base station apparatus, and a communication channel selection method for wirelessly transmitting video / audio information that requires synchronization in a passenger transport such as a passenger aircraft.

The block diagram which shows the basic composition of the radio transmission system in the 1st Embodiment of this invention The block diagram which shows the structure of the part in connection with the communication channel selection of the radio base station apparatus in the 1st Embodiment of this invention. The flowchart which shows the operation | movement procedure of the radio transmission system in the 1st Embodiment of this invention. The flowchart which shows the operation | movement procedure of the radio | wireless transmission system in the 2nd Embodiment of this invention. The figure which shows the structural example in the case of installing and using the radio | wireless transmission system in embodiment of this invention in a transport organization The figure which showed the frequency map which shows the radio communication channel of IEEE802.11a in Japan

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Content server 102 External network 103 Wireless base station apparatus 104-106 Wireless terminal device 201 Frame processing part 202 Modulation part 203 Transmission part 204 Radar wave detection part (Radio wave detection means)
205 Communication channel selection unit (communication channel selection means)
206 Data determination unit (data determination means)
301 to 303 Passenger seats 311 to 313 Screen display units 321 to 323 Audio playback headset 330 Wireless access point 331 Wired cable

Claims (16)

A first communication candidate channel that is included in a predetermined radio frequency band and shifts to another channel when radio waves of the channel are detected;
A wireless transmission system for transmitting data between a wireless base station device and a wireless terminal device via a communication path having a second communication candidate channel not included in the predetermined wireless frequency band,
Data determining means for determining whether the data is real-time data or non-real-time data;
Radio wave detecting means for detecting radio waves of the first communication candidate channel;
Communication channel selection means for selecting a communication channel for transmitting the data from the first communication candidate channel or the second communication candidate channel based on the determination result of the data determination means;
A wireless transmission system comprising: When the data determination unit determines that the data is real-time data,
The wireless transmission system according to claim 1, wherein the communication channel selection unit selects a communication channel from the second communication candidate channels. When the data determination means determines that the data is non-real time data,
The communication channel selection unit selects a communication channel from the first communication candidate channel or the second communication candidate channel based on a detection result of the radio wave detection unit. The wireless transmission system described. 4. The wireless transmission system according to claim 3, wherein the communication channel selection unit preferentially selects a communication channel from the first communication candidate channels. The radio transmission system according to claim 1, wherein the predetermined radio frequency band is a radar radio frequency band. The wireless transmission system according to claim 1, wherein the wireless base station device and the wireless terminal device are installed in a passenger accommodation area of a transportation facility. A first communication candidate channel that is included in a predetermined radio frequency band and shifts to another channel when radio waves of the channel are detected;
A wireless base station device that transmits data to a wireless terminal device via a communication path having a second communication candidate channel not included in the predetermined wireless frequency band,
Radio wave detecting means for detecting radio waves of the first communication candidate channel;
Communication channel selection means for selecting a communication channel for transmitting the data from the first communication candidate channel or the second communication candidate channel according to whether the data is real-time data or non-real-time data;
A radio base station apparatus comprising: If the data is real-time data,
The radio base station apparatus according to claim 7, wherein the communication channel selection unit selects a communication channel from the second communication candidate channels. If the data is non-real time data,
The said communication channel selection means selects a communication channel from the said 1st communication candidate channel or the said 2nd communication candidate channel based on the detection result of the said electromagnetic wave detection means. The radio base station apparatus described. The radio base station apparatus according to claim 9, wherein the communication channel selection means preferentially selects a communication channel from the first communication candidate channels. The radio base station apparatus according to claim 7, wherein the predetermined radio frequency band is a radio frequency band for radar. The radio base station apparatus according to claim 7, wherein the radio base station apparatus is installed in a passenger accommodation area of a transportation facility. A first communication candidate channel that is included in a predetermined radio frequency band and shifts to another channel when radio waves of the channel are detected;
A communication channel selection method for transmitting data between a radio base station apparatus and a radio terminal apparatus via a communication path having a second communication candidate channel not included in the predetermined radio frequency band. ,
A data determination step for determining whether the data is real-time data or non-real-time data;
A communication channel selection step of selecting a communication channel for transmitting the data from the first communication candidate channel or the second communication candidate channel based on a determination result in the data determination step;
A communication channel selection method characterized by comprising: In the data determination step, when it is determined that the data is real-time data,
The communication channel selection method according to claim 13, wherein in the communication channel selection step, a communication channel is selected from the second communication candidate channels. In the data determination step, when it is determined that the data is non-real time data,
The communication channel selection method according to claim 13, wherein the communication channel selection step selects a communication channel from the first communication candidate channel or the second communication candidate channel. The communication channel selection method according to claim 15, wherein the communication channel selection step preferentially selects a communication channel from the first communication candidate channels.

Images