JP2010098438A - Radio communication device, and radio communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication system in which a UWB device arranged in a cabin speedily structures a beacon group by reducing an influence from an adjacent beacon group that a user does not intend when entering an active state, and also reduces the influence from the adjacent beacon group even after the beacon group is structured to secure stable communication. <P>SOLUTION: The UWB device 10 is constituted such that each time electric power is supplied, a reset control unit 4 resets a UWB transmission/reception processing unit 3 in optional timing given from a control unit 5, and can optionally change the timing of a beacon scan under media access control. Further, a plurality of UWB devices 10 are installed in the cabin, and the control unit 5 of a predetermined UWB device 10 generates timing earlier than control units 5 of the remaining UWB devices 10 to quickly start beacon scanning and beacon output. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wireless communication apparatus that uses an access control method used in MB-OFDM (Multiband Orthogonal Division Multiplexing) standardized by WiMedia Alliance, and a wireless communication system that performs communication between the wireless communication apparatuses. .

MB-OFDM, which is standardized by WiMedia Alliance, is a short-range wireless communication system that performs effective communication within a short distance of about 10 m or less. In the access control method used there, an autonomous distributed media access control method is defined.
In addition, the operation of a UWB (Ultra Wide Band) device corresponding to MB-OFDM is defined for each superframe in units of 65.536 msec. The super frame includes a beacon period for transmitting a beacon signal from the UWB device and a data transmission / reception enabled period for performing data communication between the UWB devices.

  The UWB device transmits a beacon signal at a unique BS (Beacon Slot) timing in the beacon period, and exchanges various parameters with UWB devices existing in the vicinity. UWB devices that exist within a range in which beacon signals can be received from each other are established in synchronization at the same beacon start time for the superframe, and share information with each other to construct a network. A network in which peripheral UWB devices are synchronously established in the same superframe period is called a beacon group. Such a wireless communication system is described in Non-Patent Document 1.

Since the WiMedia Alliance does not have a specific provision for the scan time, generally, when a UWB device enters an active state (operational state), whether or not a beacon defined in the WiMedia Alliance exists in the vicinity is optional. The beacon scan was confirmed for an arbitrary period at the scan timing.
When the presence of a beacon is confirmed, the UWB device performs synchronization processing so that the own device also synchronizes with the synchronization timing of the superframe shared by the beacon group. That is, the UWB device determines its own unique BS from the free BS of the superframe shared by the beacon group whose existence has been confirmed, transmits a beacon signal, and joins the beacon group.
On the other hand, if the presence of a beacon cannot be confirmed, the own device transmits a beacon to generate superframe timing, establishes a beacon group, and waits for a beacon signal to be transmitted from another UWB device.

On the other hand, a conventional wireless communication device performs an authentication confirmation operation between wireless communication devices that can communicate in a wireless communication system in which a plurality of wireless networks are adjacent and the communication range of each other overlaps. A connection list for registering wireless communication devices that should communicate and a non-connection list for registering wireless communication devices that should not communicate were created and stored. In wireless communication, the wireless communication apparatus appropriately maintains the wireless communication network by referring to these lists (see, for example, Patent Document 1).
The wireless communication device of Patent Document 1 is basically targeted for a wireless LAN system, and by receiving a mutual beacon signal, a stored connection list and a non-connection list are stored while avoiding access control conflicts. By referring, data communication is performed by recognizing each other in the same wireless network, and interference is avoided by not performing data communication even if the existence of each other is recognized by a beacon in different wireless networks.

WiMedia Alliance Japanese Patent Laid-Open No. 2004-228926 (FIG. 3)

  For example, when such a conventional UWB device is arranged in a vehicle, it is assumed that the active state and the inactive state (inoperable state) are frequently repeated. For example, in the case of an ordinary automobile, power is supplied to all UWB devices in the vehicle when the accessory switch is on, and the engine is operating. To accessory UWB devices in the vehicle when the accessory switch is off when the engine is stopped. The power supply of is cut off. When active / inactive is frequently repeated, the UWB device performs an operation of constructing a beacon group by performing a beacon scan every time it enters an active state.

  When another beacon group exists in the same frequency band as a beacon group constructed by a plurality of UWB devices, that is, when a plurality of beacon groups exist in a range where UWB devices of different beacon groups can communicate with each other, Communication becomes possible by receiving a beacon signal from a beacon group other than the beacon group to which the own device belongs, and communication in the unintended beacon group competes with communication in the beacon group to which the own device belongs. have done.

FIG. 15 shows a beacon group BG8 constructed by UWB devices 81, 82, 83 arranged in a vehicle and a beacon group constructed by UWB devices 91, 92 arranged in another vehicle and existing in the same frequency band. It is explanatory drawing which shows the positional relationship of BG9, The said subject is demonstrated in detail using this figure.
In the figure, an area where the beacon group BG8 can transmit and receive a beacon signal is indicated by a dotted line, and an area where the beacon group BG9 can transmit and receive a beacon signal is indicated by a dashed line. The beacon group BG9 of another vehicle approaches the beacon group BG8, and the UWB devices 83 and 91 can receive the beacon signals of the beacon groups of each other.
In a UWB device compliant with WiMedia Alliance, in a state where an active state and a beacon group are established, resynchronization of all UWB devices included in this beacon group is performed in units of synchronized beacon groups.
Therefore, when the beacon group BG9 is considered as a center, both the UWB devices 81 and 82 are assigned to the unique BS of the superframe of the beacon group BG9 through the UWB device 83 that can receive the beacon signal of the beacon group BG9. It will be resynchronized with the group BG9. Similarly, when the beacon group BG9 is resynchronized with the beacon group BG8, the UWB device 92 is assigned to the unique BS of the superframe of the beacon group BG8 through the UWB device 91, so that the beacon group BG9 is taken into the beacon group BG8. Will be.
There is no clear definition in the WiMedia Alliance regarding how the beacon group is captured by resynchronization in units of beacon groups. Therefore, when another beacon group not intended by the user exists in the vicinity of the beacon group to which the own device belongs, the influence of the other beacon group cannot be excluded.

Therefore, when adjacent beacon groups are integrated into one beacon group as a result of resynchronization, a part of the transmission band is used due to access from a UWB device that is not intended by the user.
Moreover, even when not integrated, since the same frequency band is used between adjacent beacon groups, a beacon signal can be transmitted and received. For this reason, the two beacon groups communicate at superframe timing in an asynchronous relationship, and in some cases, a communication collision occurs due to access from the beacon group to be excluded, and the access within the beacon group intended by the user is prevented. It had an influence.

  Further, in the conventional wireless communication system such as Patent Document 1, when the first network in which the connection / disconnection list is not created is constructed, there is no specific procedure, so the beacon signal from each wireless communication device is not The transmission timing is not controlled, a beacon is started to be transmitted from an arbitrary wireless communication device, and the other wireless communication devices construct a network so as to be synchronized with the beacon. For this reason, depending on the wireless communication device that first transmits a beacon (for example, when beacon transmission is started from a wireless communication device that is not a connection list candidate that the user does not intend to connect to), the network intended by the user is quickly There were cases where it could not be built.

FIG. 16 is an explanatory diagram showing the positional relationship between UWB devices 81, 82, and 83 arranged in the vehicle and UWB devices 91 and 92 that are arranged in another vehicle near the UWB devices 91 and BG9. . In the figure, the UWB devices 81, 82, 83 are in an inactive state and are not operating. Further, it is assumed that the UWB device 83 is in a position where the beacon signal transmitted from the UWB device 91 of the beacon group BG9 can be weakly received.
In this state, when the vehicle on which the UWB devices 81, 82, and 83 are arranged is in the engine start or accessory switch on state, the UWB devices 81, 82, and 83 start beacon scans and receive surrounding beacon signals. Explore. Since the UWB device 83 can receive the beacon signal of the beacon group BG9 even though the reception power is low, if the beacon signal cannot be received, the UWB device 83 performs processing synchronized with the beacon group BG9. In addition, when the UWB device 83 first transmits a beacon signal synchronized with the beacon group BG9, the UWB device 81, 82 joins the beacon group BG9 via the UWB device 83 by receiving this beacon signal. It will be.

  Furthermore, if the vehicles of the beacon group BG9 move after the UWB devices 81, 82, 83 synchronize with the beacon group BG9, the distance between the vehicles increases, and transmission / reception of beacon signals becomes impossible. Then, the UWB devices 81, 82, and 83 start processing again from the beacon scan, and a new beacon group is reconstructed only by the UWB devices 81, 82, and 83. If large-capacity data communication is performed between any of the UWB devices 81, 82, and 83 before reconstruction, data communication may be temporarily disabled during reconstruction.

  As described above, since the conventional UWB device has an arbitrarily set beacon scan period, when the in-vehicle UWB device can receive the beacon signal of the UWB device outside the vehicle, the beacon group is based on the UWB device outside the vehicle. Is assumed to be built.

  Similarly, in a conventional wireless communication system such as Patent Document 1, when a beacon is transmitted when a different network already exists outside, a beacon from a different external network is set when the first network is constructed. Therefore, there is a case where the network intended by the user cannot be quickly constructed by performing construction based on the received different external beacons.

  From the above, when a UWB device is placed in a vehicle, a beacon group newly constructed every time the active / inactive state is repeated is affected by an adjacent beacon group not intended by the user. There was a problem of ending up.

  The present invention has been made to solve the above-described problems, and when an UWB device arranged in a vehicle is in an active state, it can reduce the influence from adjacent beacon groups not intended by the user. It is an object of the present invention to provide a wireless communication system that can quickly construct a beacon group and reduce the influence from adjacent beacon groups even after constructing a beacon group to ensure stable communication.

A wireless communication apparatus according to the present invention resets a UWB transmission / reception processing unit at a timing generated by a UWB transmission / reception processing unit that performs baseband processing and media access control, a control unit that generates arbitrary timing, and the control unit Thus, a reset control unit for controlling the timing of the beacon scan in the media access control is provided.
The wireless communication system according to the present invention includes a plurality of wireless communication devices mounted on a mobile body to form a network, and a control unit of a specific wireless communication device is a wireless communication device other than the specific wireless communication device. The timing is generated quickly.

  According to the present invention, since the timing of the beacon scan in the media access control is made arbitrary, the wireless communication device that outputs the beacon signal by performing the timing control in consideration of the arrangement of each wireless communication device mounted on the mobile body Can be specified arbitrarily. As a result, it is possible to quickly and surely construct a network of wireless communication devices inside the mobile body with as little influence as possible from the network outside the mobile body.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of a UWB device 10 according to Embodiment 1 of the present invention. A UWB device 10 used as a wireless communication device is a wireless communication antenna 1 for transmitting and receiving data, amplifies a received high-frequency signal, converts it into a baseband signal, and converts a transmitted baseband signal into a high-frequency signal. High-frequency radio processing unit 2, UWB transmission / reception processing unit 3 that performs PHY processing (baseband processing) and MAC processing (media access control) compliant with WiMedia, and a reset control unit that controls the active / inactive state of UWB transmission / reception processing unit 3 4. A control unit 5 for giving arbitrary timing to the reset control unit 4 and a memory 6 for holding timing information are provided.

FIG. 2 is an explanatory diagram showing a superframe configuration of UWB communication compliant with WiMedia. In the MB-OFDM system for performing wireless communication, an operation is defined for each superframe of 65.536 msec unit shown in FIG. One superframe is subdivided into 256 MASs (Media Access Slots), so 1 MAS is 256 μsec. Of the 256 MAS slots, the first half slot defined by the beacon period is used as a timing at which each UWB device transmits a beacon signal.
Slots other than the beacon signal are used for data transmission / reception, and become a data transmission / reception enabled period. In this data transmission / reception enabled slot, a UWB apparatus reserves an arbitrary number of MASs as a data transmission method in advance, and can be transmitted only by the reserved MAS, and a MAS that is not secured by DRP. The PCA (Priorized Content Access) method that can be freely transmitted using the PC can be used.

  The BS, which is an allocation period for transmitting a beacon signal output from each UWB device, is defined as an 85 μsec period, and 3 BSs are allocated to 1 MAS. The beacon period is determined depending on the number of UWB devices existing around the constructed network, and can be set up to a maximum of 96 BS. That is, a maximum of 32 MASs out of 256 MASs in the superframe can be used as the BS.

FIG. 3 is an explanatory diagram showing a PHY frame structure of UWB communication compliant with WiMedia. Data of the PHY frame structure transmitted and received by the UWB device is composed of a fixed-length PLCP (Physical Layer Convergence Protocol) preamble and a PLCP header, and a variable-length PSDU (PHY Service Data Unit). The beacon signal has a frame structure shown in the beacon payload.
When beacon frame information is written in the frame type data of the MAC header in the PLCP header, the frame payload becomes a beacon frame, that is, a beacon payload, and when data frame information is written, it becomes a data payload.

  The beacon payload includes unique information of the device that transmitted the beacon signal, BS number to be used, BS usage information, and PCA usage information, and these information are broadcast to the surroundings. In the example of FIG. 3, only Beacon Parameter, BPO (Beacon Period Occupancy) _IE (Information Elements), and PCA Availability_IE are shown as beacon payloads, but other information elements (IEs) can be arbitrarily added / deleted. is there.

Next, the operation of the UWB device 10 will be described. In the UWB device 10, the memory 6 holds the timing intended by the user in advance as timing information. The control unit 5 generates a timing intended by the user based on the timing information held in the memory 6 and gives the timing to the reset control unit 4. The reset control unit 4 releases the reset of the UWB transmission / reception processing unit 3 according to the timing, and sets the active state.
When the UWB transmission / reception processing unit 3 becomes active, a beacon scan is first performed. When performing a beacon scan, a beacon signal is received by the antenna 1, converted by the high-frequency radio processing unit 2, and output to the UWB transmission / reception processing unit 3. The UWB transmission / reception processing unit 3 starts processing under the control of the reset control unit 4 and analyzes the received beacon signal to confirm the existence of a UWB device in the communicable range.

When the presence of a UWB device other than the own device is confirmed by the beacon scan, the UWB transmission / reception processing unit 3 synchronizes at the same beacon start time as the superframe of the UWB device, and uses the free BS of the superframe for the own device. The unique BS is determined. Thereafter, the UWB transmission / reception processing unit 3 outputs a beacon signal with the determined unique BS. The beacon signal is converted by the high frequency radio processing unit 2 and transmitted from the antenna 1.
On the other hand, if the presence of a UWB device other than the own device is not confirmed even after performing a beacon scan for a predetermined period, the UWB transmission / reception processing unit 3 generates a beacon signal with the unique BS for the own device. The UWB device synchronized by the super frame transmits and receives a beacon frame having the frame structure shown in FIG. 3 as a beacon signal.

  Next, the operation of a wireless communication system that builds a beacon group by mounting a plurality of UWB devices on a moving body will be described. FIG. 4A is an explanatory diagram showing beacon groups constructed by the UWB devices 10a, 10b, and 10c according to Embodiment 1 of the present invention. The UWB devices 10a, 10b, and 10c shown in FIG. 4A have the same internal configuration as the UWB device 10 shown in FIG. Further, an area where the UWB device 10a can transmit and receive a beacon is indicated by a dotted line, an area where the UWB device 10b can transmit and receive a beacon is indicated by a one-dot chain line, and an area where the UWB device 10c can transmit and receive a beacon is indicated by a two-dot chain line. These UWB devices 10a, 10b, and 10c constitute a wireless communication system.

Hereinafter, the operation of the wireless communication system will be described using an example in which the wireless communication system including the UWB devices 10a, 10b, and 10c illustrated in FIG.
In order to reliably construct a beacon group between UWB devices in a vehicle, other UWB devices (for example, UWB devices 10b, 10b, etc.) in the vehicle are based on UWB devices (for example, UWB devices 10a) that are less susceptible to influence from outside the vehicle. The timing information may be set so that 10c) is synchronized with the reference. In the present embodiment, as an example, the control unit 5 of the UWB device 10a generates the earliest timing and causes the UWB transmission / reception processing unit 3 to start the processing first, and then the control unit 5 of the UWB device 10b performs the timing. The UWB transmission / reception processing unit 3 starts processing, and the control unit 5 of the UWB device 10c generates the latest timing to cause the UWB transmission / reception processing unit 3 to start the latest processing. Consider a case in which different timing information is set in each of the memories 6, 10 b and 10 c.

  The UWB devices 10a, 10b and 10c reset the timing intended by the user based on the timing information held in the memory 6 when the power is supplied when the engine of the car is started or the accessory switch is turned on. This is given to the control unit 4. Therefore, first, the UWB transmission / reception processing unit 3 of the UWB device 10a is activated and performs a beacon scan. Since the UWB devices 10b and 10c have not yet transmitted a beacon signal due to the reset timing control of the reset control unit 4, the UWB device 10a cannot confirm the existence of a UWB device other than its own device even after performing a beacon scan for a predetermined period. Start transmitting a beacon signal.

FIG. 4B is an explanatory diagram illustrating a superframe in which beacon groups constructed by the UWB devices 10a, 10b, and 10c are synchronized. The UWB device 10a transmits a beacon signal at BS2 (in accordance with WiMedia Alliance regulations).
Subsequently, the UWB transmission / reception processing unit 3 of the UWB device 10b starts processing and performs a beacon scan. When the UWB device 10b receives the beacon signal from the UWB device 10a, the UWB device 10b synchronizes with the superframe based on the beacon signal, and transmits the beacon signal using BS4 of the free BS. On the other hand, the UWB device 10a continues transmission of a beacon signal and beacon scan for each superframe, and confirms the presence of the UWB device 10b.

  Subsequently, the UWB transmission / reception processing unit 3 of the UWB device 10c starts processing, and performs a beacon scan. When the UWB device 10c receives the beacon signals from the UWB devices 10a and 10b, the UWB device 10c synchronizes with these superframes and transmits the beacon signal at the BS 5 of the free BS. On the other hand, the UWB devices 10a and 10b continue the beacon scan together with the transmission of the beacon signal to confirm the presence of the UWB device 10c.

  In this way, the UWB devices 10a, 10b, and 10c construct a beacon group synchronized with the superframe timing shown in FIG. 4B. The UWB device 10a is in BS2, the UWB device 10b is in BS4, and the UWB device 10c is in BS5. A beacon group is maintained by transmitting its own beacon signal. In addition, data communication between the UWB devices 10a, 10b, and 10c is all synchronized with the same superframe, and each UWB device secures and transfers in advance a DRP method, that is, an arbitrary MAS in a data transmission / reception enabled period. By performing communication using such a method, efficient communication control that does not cause an access failure such as a collision is performed.

Next, the operation of the wireless communication system when another beacon group BG2 approaches the beacon group BG1 of the UWB devices 10a, 10b, and 10c will be described. FIG. 5 is an explanatory diagram showing the positional relationship between a beacon group BG1 and another beacon group BG2 in the wireless device system according to Embodiment 1 of the present invention. An area where the beacon group BG1 can transmit and receive a beacon signal is indicated by a dotted line, and an area where the beacon group BG2 can transmit and receive a beacon signal is indicated by a dashed line. The beacon group BG2 is constructed by the UWB devices 20a and 20b. The UWB devices 20a and 20b include at least an antenna, a high-frequency wireless processing unit, and a UWB transmission / reception processing unit, and perform UWB wireless communication compliant with WiMedia Alliance.
FIG. 5 illustrates a state in which a beacon signal of a beacon group can be received by some UWB devices when a car of the beacon group BG2 approaches the car of the beacon group BG1.

  As described above, the UWB devices 10a and 10b perform beacon scans in order to construct the beacon group BG1, but the subsequent UWB device 10c includes a beacon signal from the UWB devices 10a and 10b and a beacon signal from the UWB devices 20a and 20b. Will be received. However, due to the characteristics of UWB wireless communication, each UWB device can only perform near field communication. Therefore, the beacon signal in the beacon group BG1 closer to the UWB device 10c is received power than the beacon signal in the beacon group BG2 farther away. Becomes larger. Therefore, the UWB device 10c can reliably construct a beacon group between UWB devices arranged in the vehicle of the beacon group BG1 by performing synchronization processing with the superframes of the UWB devices 10a and 10b that have already transmitted beacon signals. .

As described above, according to the first embodiment, every time power is supplied to the UWB device 10 installed in the vehicle, the UWB transmission / reception processing unit 3 is reset at an arbitrary timing given from the control unit 5. A reset control unit 4 for controlling the timing of the beacon scan in the media access control is provided. Also, a plurality of UWB devices 10 are installed in the vehicle, and the control unit 5 of a specific UWB device 10a generates timing earlier than the control units 5 of the remaining UWB devices 10b and 10c, and performs beacon scanning and beacon output. I started it early.
Therefore, the optimum beacon scan and beacon output can be performed in consideration of the arrangement of UWB devices in the vehicle, and the beacon group of each UWB device in the vehicle can be quickly and reliably constructed by reducing the influence from the outside of the vehicle. It becomes possible.

In the first embodiment, the reset control unit 4 cancels the reset of the UWB transmission / reception processing unit 3 and performs a series of processes starting from beacon cancellation at the timing according to the timing information held in the memory 6. Instead of the reset control unit 4, a configuration including a power control unit may be used. The power control unit controls the timing of applying power to the UWB transmission / reception processing unit 3.
Specifically, after the power is supplied to the UWB device 10, the control unit 5 gives the timing to the power control unit at a timing according to the timing information held in the memory 6, and the power control unit performs the UWB transmission / reception processing unit 3 at that timing. By applying power to the UWB transmission / reception processing unit 3, the UWB transmission / reception processing unit 3 becomes active and performs a series of processes starting from a beacon scan.

  Further, a configuration may be adopted in which a switch or the like is provided instead of the control unit 5 and the reset timing of the UWB transmission / reception processing unit 3 is controlled by giving timing information from the outside by a user operating the switch. Alternatively, a configuration may be adopted in which a switch or the like is provided instead of the power supply control unit, and the timing at which power is applied to the UWB transmission / reception processing unit 3 by giving timing information from the outside by the user operating the switch.

  Further, the information set in the memory 6 may be information specifying the number of beacon scans instead of the timing information. By setting a different number of beacon scans for each UWB device according to the arrangement of each UWB device in the moving body, the UWB device with a small number of beacon scans starts to transmit a beacon signal quickly, Many UWB devices start transmitting beacon signals late, and can arbitrarily control the timing of beacon scanning and beacon transmission.

Embodiment 2. FIG.
In the first embodiment, the wireless communication system is configured by the UWB device that can arbitrarily control the beacon scan timing. However, in this embodiment, the antenna directivity of the UWB device is changed in addition to the control of the beacon scan timing. Let
FIG. 6 is a block diagram showing a configuration of the UWB device 30 according to the second embodiment of the present invention. The UWB device 30 includes a high-frequency wireless processing unit 2a that changes the antenna directivity so that the received power of the received beacon signal is the highest. In FIG. 6, the same or corresponding parts as in FIG.

In the UWB device 30 capable of controlling the antenna directivity, the high-frequency radio processing unit 2a controls the antenna directivity to be omnidirectional until the first beacon signal is received after the power is first supplied. The beacon signal can be received.
After receiving the beacon signal, the high-frequency radio processing unit 2a controls the antenna directivity so that the beacon signal that should be received in the next superframe can be received most strongly.

Hereinafter, the operation of the UWB device 30 and the radio communication system will be described by taking a radio communication system including a plurality of UWB devices 30 as an example. FIG. 7 is an explanatory diagram showing the positional relationship between a beacon group BG3 and another beacon group BG2 in the wireless communication system according to Embodiment 2 of the present invention. The beacon group BG3 is constructed by the UWB devices 30a and 30b that can control the antenna directivity and the UWB device 10a that cannot control the antenna directivity described in the first embodiment. Each of the UWB devices 30a and 30b shown in FIG. 7 has the same internal configuration as the UWB device 30 shown in FIG. The beacon group BG2 has the same configuration as the beacon group BG2 shown in FIG.
In addition, an area where the beacon group BG3 can transmit and receive a beacon signal is indicated by a dotted line, and an area where the beacon group BG2 can transmit and receive a beacon signal is indicated by a one-dot chain line.

In the beacon group BG3, it is assumed that the UWB device 10a is set to start the beacon scan earliest, and then the UWB devices 30a and 30b start the beacon scan.
When the UWB device 10a that has finished the beacon scan earliest transmits a beacon signal at BS2, the UWB devices 30a and 30b receive the first beacon signal with the antenna directivity non-directional. Each high frequency radio processing unit 2a of the UWB devices 30a and 30b controls the antenna directivity based on the received first beacon signal so that the received power becomes the highest. Thereby, the antenna directivity as shown by a two-dot chain line in FIG. 7 is formed in the UWB devices 30a and 30b. As a result, the UWB devices 30a and 30b are difficult to receive beacon signals from other beacon groups BG2 outside the vehicle. Further, when the UWB devices 30a and 30b transmit beacon signals, they are most efficiently transmitted in the arrangement direction of the UWB device 10a, so that the beacon signal transmission power to the outside of the vehicle is low. As a result, resynchronization from a beacon group outside the vehicle that is not intended by the user can also be reduced.

FIG. 8 is an explanatory diagram showing an example in which a wireless communication system including the UWB devices 10a, 30a, and 30b shown in FIG. The UWB device 10a is disposed on the console near the center of the vehicle, the UWB device 30a is disposed on the window side of the rear seat (the seat other than the driver seat and the passenger seat), and the UWB device 30b is disposed near the rear glass at the rear of the vehicle. .
As a result of the antenna directivity of the UWB devices 30a and 30b being controlled by the respective high-frequency radio processing units 2a, the antenna directivity from the UWB devices 30a and 30b to the center of the vehicle is formed as shown by the two-dot chain line in FIG. Is done. Therefore, the influence from beacon group BG2 which exists outside the vehicle which a user does not intend at the time of transmission / reception of a beacon signal is reduced.
Even if the beacon group BG2 moves to the window side of the vehicle side surface, the antenna directivity of the UWB device 30a is directed to the vicinity of the center of the vehicle, so that the influence from the beacon group BG2 is reduced.

  For example, when the arrangement of each UWB device is determined in advance as shown in FIG. 8, the directivity of the antenna 1 is set near the center of the vehicle, even if the high-frequency radio processing unit 2 a does not control the antenna directivity. Fix it. In this case, the UWB device 30 includes the high-frequency wireless processing unit 2a and does not perform advanced antenna directivity control, and the same configuration may be provided with the inexpensive high-frequency wireless processing unit 2 as in the first embodiment. An effect is produced.

  When each UWB device is in an active state to build a beacon group, or when each UWB device is in an active state and a beacon group is built, the high-frequency radio processing unit 2a of each UWB device receives beacon transmission power and beacon reception. Sensitivity may be controlled. By carrying out like this, the influence from the external beacon group which a user does not intend and the leakage of the beacon signal from the beacon group in a vehicle can be reduced.

When a UWB device transmits a beacon signal, WiMedia Alliance stipulates that the slowest base rate of 53.3 Mbps is used. In this case, although the transmission rate is low, the longest communication distance can be expected. For this reason, during the period during which each UWB device transmits and receives beacon signals, beacon signal transmission output (lower output than during normal data communication) and beacon reception sensitivity (lower sensitivity than during normal data communication) according to the required in-vehicle distance ), The influence of the beacon signal from the external beacon group and the leakage of the beacon signal from the inside of the vehicle to the outside can be further reduced. As a result, the beacon group built in the vehicle becomes more stable.
Moreover, the influence from the external beacon group which a user does not intend can be reduced by making beacon reception sensitivity of the UWB apparatus previously arrange | positioned in the position close | similar to the vehicle body periphery small.

  As described above, according to the second embodiment, the high-frequency radio processing unit 2a of the UWB device 30 is configured for the UWB device that transmitted the beacon signal based on the beacon signal received first when the beacon group is constructed. The antenna directivity was controlled so that the maximum received power was achieved. Therefore, the in-vehicle wireless communication system configured using the UWB device 30 can reduce the influence of beacons from the beacon group outside the vehicle and the leakage of beacons from the inside of the vehicle to the outside of the vehicle. As a result, each UWB device in the vehicle can quickly and reliably construct a beacon group each time it enters an active state. In addition, after each UWB device in the vehicle constructs a beacon group, the influence of the beacon group from outside the vehicle can be eliminated.

Embodiment 3 FIG.
In the first and second embodiments, the beacon scan timing and antenna directivity of the UWB device are controlled to reduce the influence from an external beacon group, and a wireless communication system is constructed that performs reliable beacon group construction. In the present embodiment, in addition to these controls, the frequency band of wireless communication is changed.

  FIG. 9 is an explanatory diagram showing the frequency configuration of the MB-OFDM scheme defined in the WiMedia Alliance. The MB-OFDM system defined in the WiMedia Alliance has a frequency configuration in which a frequency band with a bandwidth of 528 MHz is divided into 15 bands. With this frequency configuration, band groups 1 to 5 divided into three bands are formed, and a TFC (Time Frequency Code) is determined for each band group. For example, if TFC = 1 in band group 1, frequency hopping is performed in the order of band # 1, band # 2, band # 3, and band # 1 in units of OFDM symbols. Become. Information about the band group and TFC is included in the PLCP header.

  FIG. 10 is a block diagram showing the configuration of the UWB device 40 according to Embodiment 3 of the present invention. The UWB device 40 includes a UWB transmission / reception processing unit 3a that changes the TFC of the beacon group to which the own device belongs, and a memory unit 7 that stores information about each UWB device of the beacon group to which the own device belongs. 10, parts that are the same as or equivalent to those in FIGS. 1 and 6 are given the same reference numerals, and descriptions thereof are omitted.

The UWB transmission / reception processing unit 3a constructs a beacon group by performing a beacon scan and a beacon signal transmission based on information stored in the memory unit 7. The UWB transmission / reception processing unit 3a performs a beacon scan during a period during which data communication is not performed during a data transmission / reception period excluding the beacon period in the superframe after the beacon group is constructed. When the presence of another beacon group is detected after construction, the UWB transmission / reception processing unit 3a arbitrarily changes the band group and TFC of its own beacon group based on the detected TFC. Furthermore, the UWB transmission / reception processing unit 3a stores information necessary for building a beacon group in the memory unit 7 immediately before the power supply to each device in the vehicle is stopped.
The memory unit 7 holds information necessary for constructing the beacon group BG4. This information includes beacon information in a beacon frame, information for controlling antenna directivity, PLCP header information including TFC information, unique identification information of each UWB device in the beacon group BG4, and the like.

  Hereinafter, the operation of the UWB device 40 and the wireless communication system will be described by taking a wireless communication system including a plurality of UWB devices 40 as an example. FIG. 11 is an explanatory diagram showing the positional relationship between a beacon group BG4 and another beacon group BG2 in the wireless communication system according to Embodiment 3 of the present invention. The beacon group BG4 is constructed by UWB devices 40a, 40b, and 40c having the same internal configuration as the UWB device 40 shown in FIG. The beacon group BG2 has the same configuration as the beacon group BG2 shown in FIG. Further, an area where the beacon group BG4 can transmit and receive beacon signals is indicated by a dotted line, an area where the beacon group BG2 can transmit and receive beacon signals is indicated by a one-dot chain line, and antenna directivities of the UWB devices 40b and 40c are indicated by two-dot chain lines.

  When the UWB device 40a disposed in the vehicle starts a beacon scan for the first time, the UWB transmission / reception processing unit 3a refers to the memory unit 7 to obtain a band group and TFC, which are information related to the communication frequency, and in accordance with this information, the beacon scan Send a signal. Thereafter, the UWB devices 40b and 40c also start a beacon scan and construct a beacon group BG4. Thereafter, each UWB transmission / reception processing unit 3a of the UWB devices 40a, 40b, and 40c performs a beacon scan of an arbitrary TFC of an arbitrary band group in a period other than the transmission of the beacon signal of the own device or the data transmission / reception, and the beacon group BG4 Check if there is a beacon signal other than the TFC to be used.

FIG. 12 is an explanatory diagram showing a superframe of beacon group BG4 in the wireless communication system according to Embodiment 3 of the present invention. As shown in FIG. 11, when the beacon group BG2 and the beacon group BG4 exist, the communication performed between the UWB devices 40a, 40b, and 40c of the beacon group BG4 is in the state shown in FIG. That is, the UWB devices 40a, 40b, and 40c synchronize with the super frame shown in FIG. 12, and each UWB device transmits a beacon signal at the unique BS in the beacon period.
At this time, the UWB device 20a belonging to the beacon group BG2 synchronizes with the superframe of the beacon group BG2 that is asynchronous with the beacon group BG4, and transmits the beacon signal of the own device using the unique BS of the superframe. In FIG. 12, the beacon signal of the UWB device 20a is transmitted during the data transmission and reception possible period of the superframe of the beacon group BG4.

When the UWB device 40c is close to the UWB device 20a and can transmit / receive a beacon signal to / from the UWB device 20a, as shown in FIG. 12, the UWB device 40c is connected to the UWB device 20a from the UWB device 20a during the data transmission / reception period. Influenced by beacon signal.
If the UWB device 40c is performing data communication with any UWB device in the beacon group BG4, the data communication in the beacon group BG4 is impossible in the worst case due to the influence of the beacon signal from the UWB device 20a. Become.
In order to avoid this, when detecting the presence of a beacon signal other than the TFC used by the beacon group BG4, the UWB transmission / reception processing unit 3a of the UWB device 40c determines that there is an influence other than the beacon group to which the own device belongs.

The UWB transmission / reception processing unit 3a of the UWB device 40c specifies an arbitrary TFC of an arbitrary band group, and uses the specified TFC by performing a beacon scan other than the BS transmission period and the data communication period of the own device in subsequent superframes. Confirm that there is no beacon group in the vicinity. Then, the UWB device 40c transmits information for changing the TFC to the UWB devices 40a and 40b, and simultaneously changes the TFC in the beacon group BG4 in units of superframes. The UWB transmission / reception processing unit 3a of each of the UWB devices 40a, 40b, and 40c stores information necessary for constructing the beacon group BG4 such as the changed TFC immediately before the power supply to each device in the vehicle is stopped. Save in part 7.
The UWB transmission / reception processing unit 3a is connected to the beacon according to the band group and TFC based on the information obtained from the memory unit 7 when power is supplied to each device in the vehicle and the UWB devices 40a, 40b, and 40c are activated next time. Group BG4 is constructed.
If it is confirmed that another beacon group in the vicinity is communicating in the same frequency band after building the beacon group BG4 with the changed TFC, each UWB device of the beacon group BG4 again It may be changed to any TFC.

Since WiMedia Alliance specifies that the frequency band of the band group 1 is indispensable to support, it is highly likely that the beacon group BG2 outside the vehicle also uses the TFC in the indispensable band group 1.
If each UWB device 40a, 40b, 40c and UWB device 20a, 20b initially establish a beacon group and the default frequency setting is band group 1 and TFC = 7, each UWB device in beacon group BG4 Every time it becomes active, it is influenced by the beacon group BG2 outside the vehicle using the same frequency band. Therefore, after the construction of the beacon group BG4, the UWB transmission / reception processing unit 3a uses the TFC other than the default setting set in the memory unit 7, for example, the band # 10, the band # 11, and the band # 12 which are support options in the WiMedia Alliance. Band group 4 to be changed to TFC = 6 (fixed at band # 11).
Thereafter, every time each UWB device in the vehicle becomes active, the beacon group BG4 can be constructed with the changed TFC, so that the influence from the beacon group BG2 outside the vehicle can be further reduced.

  As described above, according to the third embodiment, after the first beacon group BG4 is constructed, when the TFC (including the band group) is the same for the beacon group BG4 to which the own device belongs and the other beacon groups, UWB The UWB transmission / reception processing unit 3a of the device 40 is configured to change each UWB device of the beacon group BG4 to an arbitrary TFC of an arbitrary band group. In addition, the UWB device 40 stores information for constructing the beacon group BG4, antenna directivity information, and the like in the memory unit 7. For this reason, when the UWB device 40 becomes active after the second time and constructs the beacon group BG4, the influence from the unintended beacon group of the user in the vicinity is reduced, and the construction can be quickly performed. In addition, even after the construction of the beacon group BG4, it is difficult to be influenced by nearby beacon groups, so that a stable beacon group can be established.

Embodiment 4 FIG.
In this embodiment, when a new UWB device to be added to this beacon group is brought into a vehicle in which a plurality of UWB devices are installed and a beacon group is constructed, this new UWB device and the beacon group outside the vehicle And only the new UWB device is added to the beacon group in the vehicle.

  FIG. 13 is a block diagram showing the configuration of the UWB device 50 according to Embodiment 4 of the present invention. The UWB device 50 determines that a new UWB device has been brought in after the beacon group has been constructed, and the UWB device is brought in according to instructions from the UWB transmission / reception processing unit 3b and the UWB transmission / reception processing unit 3b that display the information on the display unit 8. A display unit 8 is provided for displaying the information on the screen. This UWB transmission / reception processing unit 3b also performs TFC change processing in the same manner as the UWB transmission / reception processing unit 3a of the third embodiment. In FIG. 13, the same or corresponding parts as those in FIGS. 1, 6, and 10 are denoted by the same reference numerals and description thereof is omitted.

  Hereinafter, the operation of the UWB device 50 and the wireless communication system will be described by taking a wireless communication system including a plurality of UWB devices as an example. FIG. 14 is an explanatory diagram showing the positional relationship between a beacon group BG5 and another beacon group BG2 in the wireless communication system according to Embodiment 4 of the present invention. The beacon group BG5 is constructed by the UWB device 50 shown in FIG. 13 and the UWB devices 40b and 40c described in the third embodiment. The beacon group BG2 has the same configuration as the beacon group BG2 shown in FIG. In addition, an area where the beacon group BG5 can transmit and receive beacon signals is indicated by a dotted line, an area where the beacon group BG2 can transmit and receive beacon signals is indicated by a one-dot chain line, and antenna directivities of the UWB devices 40b and 40c are indicated by two-dot chain lines.

  When the carry-in UWB device 60 is brought into the vehicle in which the beacon group BG5 is constructed, the following two ways are conceivable. One is a case where the power is supplied to the carry-in UWB device 60 in the vehicle, and the other is a case where the power is supplied to the carry-in UWB device 60 in the vehicle. The UWB device 60 has the same internal configuration as the UWB devices 20a and 20b.

  First, consider the case where the power is turned on to the carry-in UWB device 60 in the vehicle. The brought-in UWB device 60 first performs a beacon scan when the power is turned on in the vehicle, and detects the presence of the beacon group BG5 by receiving the beacon signal of any UWB device in the beacon group BG5. Then, the brought-in UWB device 60 secures its own unique BS from the free BS in synchronization with the superframe of the beacon group BG5 and joins the beacon group BG5.

  At this time, since the UWB devices 50, 40b, and 40c that have already built the beacon group BG5 in the vehicle are located in the close range of the carry-in UWB device 60 existing in the vehicle, the beacon signal can be directly received. Therefore, information indicating that the beacon signal of the brought-in UWB device 60 can be directly received is added to each beacon signal transmitted from the UWB devices 50, 40b, and 40c. Since the beacon signals of these UWB devices 50, 40b, and 40c are multicast in the beacon group BG5, any UWB device in the beacon group BG5 can receive the beacon signals of all UWB devices.

When the UWB devices 50, 40b, 40c can simultaneously receive the beacon signal of the brought-in UWB device 60 within one superframe, the UWB transmission / reception processing unit 3b of the UWB device 50 is brought into the vehicle. It is determined that 60 is turned on and has entered the beacon group BG5.
Then, the UWB transmission / reception processing unit 3b causes the display unit 8 to display that the new UWB device has been recognized in the vehicle, and to display a processing method for handling the new UWB device.

  When the user decides to add the brought-in UWB device 60 to the beacon group BG5 according to the display on the display unit 8, the brought-in UWB device 60 and the UWB devices 50, 40b, and 40c maintain communication as they are.

When the user decides not to add the brought-in UWB device 60 to the beacon group BG5 according to the display unit 8, data communication from the brought-in UWB device 60 while the UWB devices 50, 40b, 40c maintain the synchronization relationship. Cancel all DRP MAS reservation requests. Thus, the brought-in UWB device 60 does not perform data communication with the UWB devices 50, 40b, and 40c, and does not affect the frequency band of data communication used by the beacon group BG5.
As another method, when the user decides not to add the brought-in UWB device 60 to the beacon group BG5 according to the display unit 8, the UWB transmission / reception processing unit 3b continues to turn off the brought-in UWB device 60 on the display unit 8. To display. Since the beacon signal of the brought-in UWB device 60 is not transmitted when the user turns off the power of the brought-in UWB device 60 according to the display unit 8, the brought-in UWB device 60 is automatically deleted from the beacon group BG5.

  Next, consider a case where the brought-in UWB device 60 in a state where the power is turned on is brought into the vehicle. Since the brought-in UWB device 60 in the power-on state outputs a beacon signal, the UWB devices 50, 40b, and 40c in the beacon group BG5 are the beacon signals of the brought-in UWB device 60 in order of distance from the brought-in UWB device 60. Will continue to receive. In other words, as the brought-in UWB device 60 approaches from outside the vehicle, the number of UWB devices in the beacon group BG5 that can receive the beacon signal of the brought-in UWB device 60 increases, and when brought into the vehicle, all the UWB devices 50, 40b, 40c A beacon signal can be received. Therefore, the UWB devices 50, 40b, and 40c sequentially start transmitting beacon signals to which information indicating that the beacon signal of the brought-in UWB device 60 has been directly received can be added.

  The UWB transmission / reception processing unit 3a of the UWB device 50 analyzes the beacon signals of the UWB devices 40b and 40c, and all UWB devices 50, 40b and 40c in the beacon group BG5 continuously bring in the UWB device at any given time. When a beacon signal different from that of the UWB devices 50, 40b, and 40c can be received at a timing other than the beacon period of the superframe of the beacon group BG5, the UWB device 60 is brought into the vehicle. Judge that Similarly to the above, the UWB transmission / reception processing unit 3b displays on the display unit 8 that the new UWB device has been recognized in the vehicle, and also displays the processing method for the treatment of the new UWB device.

When the user decides to add the brought-in UWB device 60 to the beacon group BG5 according to the display on the display unit 8, the UWB transmission / reception processing unit 3b continues to display the procedure for resynchronization of the brought-in UWB device 60 on the display unit 8. To prompt the user to join the beacon group BG5 of the brought-in UWB device 60.
As the resynchronization processing, for example, in order to cause the carry-in UWB device 60 to perform a beacon scan, the UWB transmission / reception processing unit in the carry-in UWB device 60 is reset and the process is restarted.

If the user decides not to add the brought-in UWB device 60 to the beacon group BG5 according to the display unit 8, the communication of the brought-in UWB device 60 is likely to affect the communication in the beacon group BG5. The UWB devices 50, 40b, and 40c simultaneously change to a band group and TFC different from the band group and TFC used by the carry-in UWB device 60 in units of superframes. Alternatively, the power of the brought-in UWB device 60 may be turned off.
Thereby, the brought-in UWB device 60 does not affect the communication of the UWB devices 50, 40b, and 40c.

  Note that there is a high possibility that all UWB devices 50, 40b, and 40c in the beacon group BG5 in the vehicle cannot normally receive a beacon signal from the beacon group BG2 outside the vehicle that is not intended by the user. Therefore, even if a beacon signal different from the UWB devices 50, 40b, and 40c is transmitted at a timing other than the beacon period of the beacon group BG5, all the UWB devices 50, 40b, and 40c of the beacon group BG5 are within a certain time. If the signals cannot be received continuously or simultaneously, the UWB device that transmitted the beacon signal is not the brought-in UWB device 60 brought in the vehicle, but the UWB devices 20a and 20b belonging to the beacon group BG2 outside the vehicle not intended by the user. It can be distinguished.

As described above, according to the fourth embodiment, when the carry-in UWB device 60 is brought into the vehicle from the outside, it is detected that the beacon of the carry-in UWB device 60 has been received, and the new carry-in UWB device 60 is installed in the vehicle. The UWB transmission / reception processing unit 3b that determines that the data has been brought in and the display unit 8 that displays information about the determination result input from the UWB transmission / reception processing unit 3b to the user are provided.
Therefore, it is appropriately determined whether the communication is from a temporary beacon group BG2 outside the vehicle or from the brought-in UWB device 60, and the user is notified whether the brought-in UWB device 60 can join the in-car beacon group BG5. Can show. As a result, each UWB device in the in-vehicle beacon group BG5 executes a process intended by the user for the brought-in UWB device 60, an erroneous resynchronization process to the brought-in UWB device 60, and a data communication band from the brought-in UWB device 60. It is possible to prevent the execution of the acquisition process and the like, further reduce the influence from the external beacon group, and realize a stable beacon group.

  It is assumed that the UWB transmission / reception processing unit 3a of the UWB device 50 receives a vehicle speed pulse signal from the vehicle and the newly detected UWB is assumed on the assumption that the UWB device brought in from outside the vehicle is not brought in from the outside of the vehicle. Even a UWB device that brings in a device may be configured not to permit joining without distinguishing between beacon groups outside the vehicle.

  As described above, by making the wired network in the vehicle wireless in the first to fourth embodiments, there is no restriction on the arrangement of each UWB device, and there are no more wires for transmitting / receiving data between the UWB devices. Therefore, the weight of the entire vehicle can be reduced.

It is a block diagram which shows the structure of the UWB apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the structure of the super-frame of UWB communication based on WiMedia in the radio | wireless communications system which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the PHY frame structure of UWB communication based on WiMedia in the radio | wireless communications system which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the beacon group which the UWB apparatus which concerns on Embodiment 1 of this invention comprises. It is explanatory drawing which shows the super-frame timing of the beacon group which the UWB apparatus which concerns on Embodiment 1 of this invention comprises. It is explanatory drawing which shows the positional relationship of the beacon group of the radio | wireless communications system which concerns on Embodiment 1 of this invention, and another beacon group. It is a block diagram which shows the structure of the UWB apparatus which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows the positional relationship of the beacon group of the radio | wireless communications system which concerns on Embodiment 2 of this invention, and another beacon group. It is explanatory drawing which shows an example which arrange | positions the radio | wireless communications system which concerns on Embodiment 2 of this invention in a normal vehicle. It is explanatory drawing which shows the frequency structure of the MB-OFDM system prescribed | regulated to WiMedia Alliance which the radio | wireless communications system which concerns on Embodiment 3 of this invention uses. It is a block diagram which shows the structure of the UWB apparatus which concerns on Embodiment 3 of this invention. It is explanatory drawing which shows the positional relationship of the beacon group of the radio | wireless communications system which concerns on Embodiment 3 of this invention, and another beacon group. It is explanatory drawing which shows the super frame of the beacon group of the radio | wireless communications system which concerns on Embodiment 3 of this invention. It is a block diagram which shows the structure of the UWB apparatus which concerns on Embodiment 4 of this invention. It is explanatory drawing which shows the positional relationship of beacon group BG5 and another beacon group BG2 of the radio | wireless communications system which concerns on Embodiment 4 of this invention. It is explanatory drawing which shows the positional relationship of the some beacon group constructed | assembled by the conventional UWB apparatus. It is explanatory drawing which shows the positional relationship of the conventional UWB apparatus of the non-active state, and the conventional UWB apparatus which has constructed the beacon group in the vicinity.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Antenna, 2, 2a High frequency radio | wireless processing part, 3, 3a, 3b UWB transmission / reception processing part, 4 Reset control part, 5 Control part, 6 Memory, 7 Memory part, 8 Display part 8, 10, 10a, 10b, 10c, 30, 30a, 30b, 40, 40a, 40b, 40c, 50 UWB device, 60 carry-in UWB device.

Claims (9)

In a wireless communication apparatus that is mounted on a mobile body and forms a network with another wireless communication apparatus mounted on the mobile body and performs UWB communication in accordance with WiMedia Alliance,
A UWB transmission / reception processing unit for performing baseband processing and media access control;
A control unit for generating an arbitrary timing;
A wireless communication apparatus comprising: a reset control unit that controls a timing of a beacon scan in the media access control by resetting the UWB transmission / reception processing unit at a timing generated by the control unit. In a wireless communication apparatus that is mounted on a mobile body and forms a network with another wireless communication apparatus mounted on the mobile body and performs UWB communication in accordance with WiMedia Alliance,
A UWB transmission / reception processing unit for performing baseband processing and media access control;
A control unit for generating an arbitrary timing;
A wireless communication apparatus comprising: a power control unit that controls a beacon scan timing in the media access control by supplying power to the UWB transmission / reception processing unit at a timing generated by the control unit.   3. The wireless communication apparatus according to claim 1, wherein the control unit generates timing according to timing information given from outside.   The high-frequency wireless processing unit that changes the antenna directivity in a direction in which a beacon transmitted from another wireless communication device constituting the network to which the device belongs can be received is provided. 4. The wireless communication device according to claim 1.   The wireless communication device according to claim 4, wherein the high-frequency wireless processing unit changes the beacon transmission power and the beacon reception sensitivity according to the internal distance of the moving body.   The UWB transmission / reception processing unit, when the frequency band of communication used by the other wireless communication device constituting the network to which the own device belongs and the frequency band of communication used by the wireless communication device other than the network are the same, 6. The wireless communication apparatus according to claim 4, wherein a frequency band of communication used by the other wireless communication apparatus is changed.   Before the power source of the moving body stops, the power supply to the other wireless communication devices constituting the network to which the own device belongs is shut off, and information on the network configuration and the antenna directivity of the own device The wireless communication apparatus according to claim 4, further comprising: a memory unit that stores information regarding the wireless communication device. A display unit for displaying information input from the UWB transmission / reception processing unit;
When the UWB transmission / reception processing unit detects that all wireless communication devices constituting the network to which the own device belongs has received a new beacon, the display indicates that the new wireless communication device has been brought into the mobile body. The wireless communication apparatus according to claim 7, wherein the wireless communication apparatus is displayed on a screen. A wireless communication system that forms a network by mounting a plurality of wireless communication devices according to any one of claims 1 to 8 on a mobile body,
The control unit of the specific wireless communication device generates a timing for beacon scanning earlier than the wireless communication devices other than the specific wireless communication device.

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