JP2000201164A - Wireless communication method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continue communication with high reliability despite a local rainfall by setting the transmission capacity of a stand-by circuit smaller than that of an active circuit that secure the connection among the communication nodes and switching the active circuit to the standby circuit to continue the communication if the active circuit has its abnormality. SOLUTION: In this radio communication network system, the communication nodes 10-1, 10-2, 10-3 and 10-4 are connected to each other in a ring shape via the working circuits (radio transmission lines of a working system) 21-1, 21-2, 21-3 and 21-4 and the standby circuits (radio transmission lines of a standby system) 22-1, 22-2, 22-3 and 22-4, respectively. Then the transmission capacity of the circuits 22-1 to 22-4 is reduced compared with that of the circuits 21-1 to 21-4. Thus, the necessary reception input levels of circuits 22-1 to 22-4 can be reduced by a degree equivalent to the reduced transmission capacity to secure the desired circuit quality.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication network in which a plurality of communication nodes each accommodating one or a plurality of terminals are connected in a ring by an active radio transmission line and a protection radio transmission line having different transmission directions. More specifically, the transmission capacity of the standby radio transmission path is set to be smaller than the transmission capacity of the working radio transmission path, and if a line abnormality occurs in the working radio transmission path, The present invention relates to a wireless communication method and apparatus capable of switching from a transmission path to a standby transmission path and continuing communication.

[0002]

2. Description of the Related Art Recently, a plurality of communication nodes each accommodating one or a plurality of terminals are connected in a ring shape using a radio transmission line in order to relatively easily and quickly construct a subscriber transmission line. A wireless communication network has been proposed.

In this type of wireless communication network, in order to ensure the reliability of the transmission path, the above-mentioned wireless transmission path is doubly connected by an active transmission line and a protection transmission line having different transmission directions. Configuration is considered.

FIG. 10 is a block diagram showing an example of this type of wireless network.

In FIG. 10, this wireless network includes a plurality of communication nodes 10-1, 10-2, 10-3,
Reference numeral 10-4 denotes a working wireless transmission path (hereinafter, referred to as a working line) 21-1, 21-2, 21-3, 21-4 and a protection system wireless transmission path (hereinafter, referred to as a protection line) 22-1,
22-2, 22-3 and 22-4 are connected in a ring shape.

Here, the data transmission directions of the working lines 21-1 to 21-4 and the protection lines 22-1 to 22-4 are as follows.
22-4 are set in opposite directions such as counterclockwise.

The reason why the data transmission directions of the working lines 21-1 to 21-4 and the protection lines 22-1 to 22-4 are set to be opposite to each other is, for example, that the working lines 21-1 to 21-4
When a failure occurs in any one of 21-4, the failure can be remedied by turning back the line at two communication nodes sandwiching the failure location, thereby ensuring reliability. Because.

FIG. 11 shows the configuration shown in FIG.
FIG. 9 is a diagram illustrating a state of a loopback when a failure occurs.

That is, in FIG. 11, for example, when a failure occurs in the working line 21-1, the communication nodes 10 at both ends of the working line 21-1 in which the failure has occurred are considered.
The working line 21-4 is replaced by the protection line 22-4 by -1 and 10-2.
Loopback 23-1 and backup line 22-
Loopback 23-2 that loops back 1 to working line 21-2
Is formed.

According to such a configuration, the working line 21-
1 between the communication node 10-1 and the communication node 10-2, the protection line 22-4, the communication node 10-4, the protection line 22-3, and the communication node 10-
3. Communication becomes possible via the protection line 22-2, the working line 21-2, the communication node 10-3, the working line 21-3, the communication node 10-4, and the working line 21-4, and the reliability of communication is improved. Can be improved.

[0011]

A signal of a frequency in the millimeter wave band is usually used as a radio transmission line of this type of subscriber system. However, a large amount of rainfall occurs, and this causes a predetermined rainfall margin to be reduced. Beyond that, signal propagation loss occurs, which may cause a line break.

When a large amount of rainfall occurs between communication nodes, this line break can be remedied by performing a line return as shown in FIG. 11, but a specific communication node, for example, FIG. Considering a case where a large amount of rainfall or the like occurs around the communication node 10-1 of 11 and a failure of the working line 21-1 is detected, the working line 21-4 and the protection line are similar to the working line 21-1. It is conceivable that the line quality is also deteriorated in 22-4, which caused a problem that the communication reliability could not be ensured even if the line was looped back as shown in FIG.

It is an object of the present invention to provide a wireless communication method and apparatus capable of continuing communication with high reliability even in the case of local rainfall.

[0014]

In order to achieve the above object, according to the present invention, a plurality of communication nodes each accommodating one or a plurality of terminals are provided with an active wireless transmission line and a protection line having different transmission directions. In a wireless communication method in a wireless communication network connected in a ring by a system wireless transmission line, the transmission capacity of the standby system wireless transmission line is set smaller than the transmission capacity of the working system wireless transmission line, When a line abnormality occurs, the communication is continued by switching from the working wireless transmission line to the protection transmission line.

According to a second aspect of the present invention, in the first aspect, the wireless network is connected to one of the plurality of communication nodes.
A network management device that manages the overall operation of the wireless network, wherein the communication node detects a signal error rate of the working wireless transmission line as a line abnormality when the signal error rate exceeds a predetermined threshold. Notifying the network management device, the network management device switches from the working radio transmission line to the protection radio transmission line on the condition that no line abnormality has occurred in the protection radio transmission line. Features.

According to a third aspect of the present invention, in the first aspect of the present invention, when the signal error rate of the working radio transmission line exceeds a predetermined threshold, the communication node transmits the signal to the communication node. An abnormality is detected, and switching from the working wireless transmission line to the standby wireless transmission line is performed on the condition that no line abnormality has occurred in the working wireless transmission line.

According to a fourth aspect of the present invention, there is provided a wireless communication system in which a plurality of communication nodes each accommodating one or a plurality of terminals are connected in a ring by an active wireless transmission line and a standby wireless transmission line having different transmission directions. In a wireless communication device in a communication network, a transmission capacity of the protection-type wireless transmission path is set to be smaller than a transmission capacity of the working-type wireless transmission path.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, a network management device is connected to any one of the plurality of communication nodes and manages the entire operation of the wireless network. When the network management device receives a notification of a line abnormality of the working wireless transmission line from any one of the plurality of communication nodes, the network management device connects to the working wireless transmission line. A line switching means is provided for switching from the working wireless transmission path to the standby wireless transmission path on condition that no abnormality has occurred.

According to a sixth aspect of the present invention, in the fourth aspect of the present invention, when the signal error rate of the working radio transmission line exceeds a predetermined threshold, the communication node transmits the signal to the communication node. When a line abnormality of the working wireless transmission line is detected by the line abnormality detecting means for detecting as an abnormality and the line abnormality detecting means, the condition is that no line abnormality has occurred in the working wireless transmission line. Line switching means for switching from the working wireless transmission path to the protection wireless transmission path.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a radio communication method and apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of a wireless communication network system configured by applying a wireless communication method and apparatus according to the present invention.

In FIG. 1, portions having the same functions as in the configuration shown in FIG. 10 are denoted by the same reference numerals for convenience of explanation.

In FIG. 1, the wireless communication network system includes a plurality of communication nodes 10-1, 10-2, 1
0-3 and 10-4 are working lines (working wireless transmission paths) 2
1-1, 21-2, 21-3, 21-4 and protection line (protection wireless transmission path) 22-1, 22-2, 22-
3, 22-4 and are connected in a ring shape.

Here, the data transmission directions of the working lines 21-1 to 21-4 and the protection lines 22-1 to 22-4 are as follows.
22-4 are set in opposite directions such as counterclockwise.

The communication node 10-1 is connected to a network management device 30 for managing the entire wireless communication network system.

The wireless communication network system shown in FIG. 1 is significantly different from the configuration shown in FIG. 10 in that the transmission capacity of the protection lines 22-1 to 22-4 is smaller than that of the working lines 21-1 to 21-4. This is a point that is set smaller than the transmission capacity.

According to such a configuration, the working line 21-
Signals transmitted through 1-2-4 and protection lines 22-1 through 22-22
In the case where the same modulation scheme is used for the signal transmitting -4, the protection lines 22-1 to 22-4 reduce the reception input level necessary to secure the desired line quality by the reduced transmission capacity. It becomes possible.

For example, when the transmission capacity of the protection lines 22-1 to 22-4 is reduced to 1/10 of the transmission capacity of the working lines 21-1 to 21-4, the protection lines 22-1 to 22-4 are considered.
The occupied frequency bandwidth of the working line 22-4 is
This is 1/10 of the occupied frequency bandwidth of 1-4. As a result, the working lines 21-1 to 21-4 and the protection lines 22-1 to 22-1
When trying to ensure the same line quality with 22-4,
In the protection lines 22-1 to 22-4, the working line 21-
A reception input level that is 10 dB lower than 1-21-4 will suffice.

For this reason, for example, the working lines 21-1 to 21-2
Protection lines 22-1 to 22-4 for the transmission capacity of 1-4
When the transmission capacity is reduced to 1/10, 10 dB can be allocated to the rainfall margin with respect to the reception input level, and the protection line 22-2 is more reliable than the working lines 21-1 to 21-4. 1 to 22-4 can be secured.

That is, as shown in FIG. 1, the transmission capacities of the protection lines 22-1 to 22-4 are changed to the working lines 21-1 to 21-2.
If it is set smaller than the transmission capacity of 1-4, the protection line 22
-1 to 22-4 can provide a larger rainfall margin than the working lines 21-1 to 21-4. For example, if the working lines 21-1 to 21-4 are disconnected due to a large amount of rain, etc. Even if it is determined, the communication can be continued by using the protection lines 22-1 to 22-4.

Therefore, in the present invention, the protection lines 22-1 to 22-2 connecting the communication nodes 10-1 to 10-4 are connected.
The transmission capacity of 2-4 is set smaller than the transmission capacity of the working lines 21-1 to 21-4, and if a line abnormality occurs in the working lines 21-1 to 21-4, the working lines 21-1 to 21-
4 to the protection lines 22-1 to 22-4 to continue communication.

In the above configuration, the protection lines 22-1 to 22-4 are connected to the working lines 21-1 to 21-.
Since the transmission capacity is smaller than in No. 4, if a path is established between communication nodes as in the case of circuit switching, the initial bandwidth cannot be secured, but a logical path is established as in the case of packet switching. In that case, the processing speed is only slightly reduced. However, for communications that require real-time properties such as voice calls, it is necessary to perform processing such as raising the priority.

FIG. 2 is a block diagram showing a schematic configuration of the communication node shown in FIG.

FIG. 2 shows the configuration of the communication node 10-1 of the communication nodes 10-1 to 10-4 shown in FIG. The other communication nodes 10-2 to 10-4
Has the same configuration as the communication node 10-1 except that the network management device 30 is connected.

In FIG. 2, the communication node 10-1
Are transmission units 12-1 and 12 for performing transmission processing of signals exchanged by the ATM switching unit 11;
-1 as a radio wave using the signal transmitted at -1
1, an antenna 13-2 for receiving a radio wave from the protection line 22-1, and an antenna 13-2.
Receiving section 12-2 for processing the signal received by
An antenna 15-1 for receiving radio waves from 1-4, a receiving unit 14-1 for processing a signal received by the antenna 15-1,
A transmitting unit 14-2 for transmitting a signal exchanged by the ATM switching unit 11, and an antenna 1 for transmitting the signal transmitted by the transmitting unit 14-2 as a radio wave to the protection line 22-4;
5-2.

FIG. 3 is a block diagram showing a detailed configuration of the transmitting section and the receiving section shown in FIG.

In FIG. 3, the modulation / demodulation section 120 and the radio section 140 correspond to the transmission section 12-1 and the reception section 12-2 shown in FIG. 2, and the antenna 13 is the antenna 13-1 shown in FIG. And 13-2.

In FIG. 3, the ATM switching unit 11
M switch 110, control unit 111, interface (I
/ F) 112 and an interface (I / F) 113. The ATM switch 110 includes a control unit 11
1. The interface (I / F) 112, the interface (I / F) 113, and the network management device 30 are connected.

The modem 120 is connected to the interface (I / F) 112 and interface (I / F) 113 of the ATM switching unit 11 via optical fibers 114 and 115, and is connected to an optical-electrical converter (O / E). 121, a modulator 122, a mixer 123, a local oscillator 124, a bandpass filter 125, a bandpass filter 126, a mixer 127, a local oscillator 128, a demodulator 129, and an electro-optical converter 130.

The radio section 140 is connected to the modem section 120, and includes a mixer 141, a local oscillator 142, a bandpass filter 143, a power amplifier 144, a bandpass filter 145, a circulator 146, a bandpass filter 147, an amplifier 148, and a mixer. 149, local oscillator 1
50 and a band pass filter 151.

Here, the optical signal output from the interface (I / F) 112 of the ATM switching unit 11 is transmitted via an optical fiber 114 to the optical-electrical conversion unit (O) of the modulation / demodulation unit 120.
/ E) 121, where it is converted to an electrical signal,
Predetermined modulation is performed by the modulator 122. The signal modulated by the modulator 122 is converted by the mixer 141 into a local oscillator 142.
Are mixed and up-converted, and passed through the band-pass filter 125 to the mixer 141 of the radio unit 140.
Is added to

In the mixer 141 of the radio section 140, the output of the local oscillator 142 is mixed with the output of the band-pass filter 125 of the modem section 120 and further up-converted, and the band-pass filter 143, the power amplifier 144, the band-pass filter 144, The signal is transmitted from the antenna 13 to the working line 21-1 via the circulator 146 as a radio wave. The above configuration corresponds to the transmission unit 12-1 shown in FIG.
Is equivalent to

The radio wave from the protection line 22-1 is received by the antenna 13 and is applied to the mixer 149 via the circulator 146, the band-pass filter 147 and the amplifier 148 of the radio unit 140.
The outputs of 0 are mixed and down-converted, and applied to the mixer 127 via the band-pass filter 151 and the band-pass filter 126 of the modem 120.

Here, the signal is mixed with the output of the local oscillator 128 and further down-converted.
The signal is added to the interface (I / F) 113 of the ATM switching unit 11 via the optical conversion unit 130 and the optical fiber 115. The above configuration corresponds to the receiving unit 12-2 shown in FIG.

In the above configuration, the pass band of the band pass filter 126 of the modem unit 120 is set narrower than the pass band of the band pass filter 125, thereby reducing the transmission capacity of the protection lines 22-1 to 22-4 to the working line. 21
It is possible to set smaller than the transmission capacity of -1 to 21-4.

FIG. 4 is a diagram showing a normal data flow in the wireless communication network system shown in FIG.

As shown in FIG. 4, in the wireless communication network system shown in FIG.
In a state where all of the nodes 1-4 are normal, the communication node 1
0-1 to 10-4 transmit data between the communication nodes 10-1 to 10-4 using the working lines 21-1 to 21-4.

FIG. 5 is a diagram showing the flow of data when an abnormality occurs in the working line in the wireless communication network system shown in FIG.

As shown in FIG. 5, the working lines 21-1 to 21-2
If a failure occurs in any of the communication nodes 1-4 and is detected as an abnormality, each of the communication nodes 10 through the working lines 21-1 to 21-4 under the control of the network management device 20.
From the state where data transmission between -1 to 10-4 is being performed, each of the communication nodes 10 using the protection lines 22-1 to 22-4.
The state is switched to a state in which data transmission between -1 to 10-4 is performed.

That is, in the state shown in FIG. 5, the protection line 22-1 replaces the working lines 21-1 to 21-4.
To 22-4, each communication node 10-1 to 10-1
Transmission of data between 0 and 4 is continued.

Next, a procedure for switching from the working lines 21-1 to 21-4 to the protection lines 22-1 to 22-4 will be described with reference to flowcharts shown in FIGS.

FIG. 6 is a flowchart showing the processing of the communication node in the wireless communication network system shown in FIG.

Each of the communication nodes 10-1 to 10-4 of the wireless communication network system shown in FIG. 1 is in a normal state where communication is performed using the working lines 21-1 to 21-4 shown in FIG. The data error rates of the working lines 21-1 to 21-4 are monitored (step 501).

Then, it is checked whether the monitored data error rate has exceeded a predetermined threshold value (step 502). Here, if the monitored data error rate does not exceed the predetermined threshold value (NO in step 502), step 50
Returning to 1, if it exceeds the predetermined threshold (YES in step 502), an alarm is sent to the network management device 30 indicating that the working line is abnormal.

Next, it is checked whether or not an inquiry has been received from the network management apparatus 30 as to whether the protection line is normal (step 504). Here, the network management device 3
If no inquiry has been received from 0 since the protection line is normal (NO in step 504), step 50
Returning to step 4, when it is determined that an inquiry has been received from the network management apparatus 30 as to whether the protection line is normal (YES in step 504), an alarm for the protection line is confirmed (step 505). If there is a line alarm (YES in step 506), the network management device 3
A warning of the protection line is sent to 0 (step 507).

However, if it is determined in step 506 that there is no alarm for the protection line (NO in step 506), the flow advances to step 508.

In step 508, it is checked whether a line switching instruction has been received from the network management device 30. Here, if the line switching instruction has not been received from the network management device 30 (NO in step 508), this process ends. If the line switching instruction has been received from the network management device 30 (step 508). And YE
S) The switching from the working line to the protection line is executed (step 509).

Next, the status of the switched protection line is notified to the network management device 30. Then, it is checked whether there is an instruction from the network management device 30 to switch back from the protection line to the working line (step 511). Here, if there is no instruction from the network management apparatus 30 to switch back from the protection line to the working line (NO in step 511), this processing is terminated as line switching end. However, if there is an instruction from the network management apparatus 30 to switch back from the protection line to the working line (YES in step 511), the switching back from the protection line to the working line is executed, and this processing is terminated.

FIG. 7 corresponds to FIG. 1 corresponding to the processing shown in FIG.
6 is a flowchart showing a process performed by the network management device of the wireless communication network system shown in FIG.

In FIG. 7, the network management device 30
First, it is checked whether or not an alert for the working line has been received from the communication node (step 521). Here, if it is determined that an alert for the working line has not been received from the communication node (NO in step 521), the process returns to step 521, but if it is determined that an alert for the working line has been received from the communication node. (YES in step 521), and then inquire of each communication node whether the protection line is normal.

Then, it is checked whether or not a protection line alarm has been received from the communication node responding to the inquiry (step 523). Here, when an alarm for the protection line has not been received from the communication node (NO in step 523), a switching instruction for instructing switching from the working line to the protection line is transmitted to each communication node (step 524). .

Next, by this switching, it is checked whether or not the protection lines are normal for all communication nodes (step 525). Here, if it is determined that the protection line is normal for all communication nodes (YES in step 525), the process is terminated as line switching is completed. If it is determined that the protection line is not normal for all communication nodes, (NO in step 525), a switchback instruction to switch back from the protection line to the working line is transmitted to each communication node, and the process ends.

In step 523, when an alarm of the protection line is received from the communication node (Y in step 523)
ES), since there is an abnormality in the protection line, the process of switching from the working line to the protection line is stopped, and this processing ends.

In the above-described processing, the case where the line switching is performed under the initiative of the network management device 30 has been described. However, when a line abnormality occurs, each communication node is configured to autonomously perform the line switching. Is also good.

Next, when each communication node autonomously switches the line, the protection line 2 is switched from the working lines 21-1 to 21-4.
The procedure for switching to 2-1 to 22-4 will be described with reference to the flowcharts shown in FIGS.

FIG. 8 is a flowchart showing the processing of the communication node in the wireless communication network system shown in FIG.

In FIG. 8, first, the data error rate of the working line is monitored (step 601), and it is checked whether the monitored data error rate exceeds a predetermined threshold value (step 602). If the monitored data error rate does not exceed the predetermined threshold value (N in step 602)
O) Return to step 601, but if the threshold is exceeded (YES in step 602), a request is made to each communication node to switch from the working line to the protection line using the protection line (step 603). ).

Then, it is determined whether all communication nodes are normal based on information from other communication nodes (step 604).
Here, if it is determined that all communication nodes are not normal (NO in step 604), the process of switching from the working line to the protection line ends, but if it is determined that all communication nodes are normal (step 604). If YES in step 604), switching from the working line to the protection line is executed (step 605).

Next, based on information from other communication nodes, it is checked whether or not the protection lines are normal for all communication nodes (step 60).
6) Here, if all the protection lines are normal, the line switching is completed and the process is terminated.

However, if it is determined in step 606 that the protection lines are not normal for all communication nodes (step 60)
6), a switchback instruction is sent to each communication node to switch back from the protection line to the working line, and the process ends.

FIG. 9 corresponds to FIG. 1 corresponding to the processing shown in FIG.
6 is a flowchart showing a process performed in another communication node of the wireless communication network system shown in FIG.

In FIG. 9, first, it is checked whether a request for switching from the working line to the protection line has been received from another communication node (step 611). Here, if a request to switch from the working line to the protection line has not been received (step 611).
NO), the process returns to step 611, but if a request to switch from the working line to the protection line has been received (step 61).
It is checked whether the protection line is normal (YES at 1) (step 6).
13).

If it is determined that the protection line is normal (YES in step 613), the switching from the working line to the protection line is performed (step 614), and then the protection line related to this switching is performed. And the other communication nodes are notified of the state of the protection line (step 61).
6).

Then, it is checked whether an instruction to switch back from the protection line to the working line has been received from another communication node (step 617). Here, if no instruction to switch back from the protection line to the working line is received from another communication node (NO in step 617), this processing is terminated as line switching completion.

However, in step 617, when an instruction to switch back from the protection line to the working line is received from another communication node (YES in step 617), switching back from the protection line to the working line is executed (step 617). 618), this process ends.

If it is determined in step 613 that the protection line is not normal (NO in step 613), a notification of the protection line abnormality is sent to another communication node (step 615), and this processing ends.

As described above, according to the present invention, the communication node 1
Protection lines 22-1 to 22 connecting between 0-1 to 10-4
-4 is set smaller than the transmission capacity of the working lines 21-1 to 21-4, and when a line abnormality occurs in the working lines 21-1 to 21-4, the working lines 21-1 to 21-4 are set.
Is provided so that communication can be continued by switching to the protection lines 22-1 to 22-4 from the above, so that communication can be continued with high reliability even when local rainfall occurs. can do.

[0078]

As described above, according to the present invention, the transmission capacity of the protection line connecting the communication nodes is set to be smaller than the transmission capacity of the working line. Since the communication is switched from the working line to the protection line to continue the communication, it is possible to provide a wireless communication method and apparatus capable of continuing the communication with high reliability even in the case of local rainfall. It works.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a wireless communication network system configured by applying a wireless communication method and device according to the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a communication node shown in FIG. 1;

FIG. 3 is a block diagram illustrating a detailed configuration of a transmission unit and a reception unit illustrated in FIG. 2;

FIG. 4 is a diagram showing a normal data flow in the wireless communication network system shown in FIG. 1;

FIG. 5 is a diagram showing a data flow when an abnormality occurs in a working line in the wireless communication network system shown in FIG. 1;

FIG. 6 is a flowchart showing processing of a communication node in the wireless communication network system shown in FIG. 1;

FIG. 7 is a flowchart showing processing performed by the network management device of the wireless communication network system shown in FIG. 1 corresponding to the processing shown in FIG. 6;

FIG. 8 is a flowchart showing processing of a communication node in the wireless communication network system shown in FIG. 1;

FIG. 9 is a flowchart showing processing performed by another communication node of the wireless communication network system shown in FIG. 1 corresponding to the processing shown in FIG. 8;

FIG. 10 is a block diagram showing an example of this type of wireless network.

FIG. 11 is a diagram showing a state of line return when a failure occurs in the configuration shown in FIG. 10;

[Explanation of symbols]

10-1, 10-2, 10-3, 10-4 Communication node 21-1, 21-2, 21-3, 21-4 Working line (working wireless transmission line) 22-1, 22-2, 22-3, 22-4 Protection line (protection wireless transmission path) 30 Network management device 11 ATM switching unit 12-1 Transmission unit 12-2 Receiving unit 13 Antenna 13-1 Antenna 13-2 Antenna 14-1 Receiving unit 14-2 Transmission unit 15-1 Antenna 15-2 Antenna 110 ATM switch 111 Control unit 112 Interface (I / F) 113 Interface (I / F) 120 Modulation / demodulation unit 121 Optical-electrical conversion unit (O / E) 122 Modulation unit 123 mixer 124 local oscillator 125 bandpass filter 126 bandpass filter 127 mixer 128 local oscillator 129 demodulator 130 - optical conversion unit 140 radio unit 141 mixer 142 local oscillator 143 band-pass filter 144 power amplifier 145 band-pass filter 146 circulator 147 band-pass filter 148 amplifier 149 Mixer 150 local oscillator 151 band-pass filter

Claims (6)

[Claims] 1. A wireless communication method in a wireless communication network in which a plurality of communication nodes each accommodating one or a plurality of terminals are connected in a ring by an active wireless transmission line and a standby wireless transmission line having different transmission directions. The transmission capacity of the protection system wireless transmission path is set to be smaller than the transmission capacity of the working system wireless transmission path.If a line abnormality occurs in the working system wireless transmission path, the protection system transmission A wireless communication method characterized by switching to a road and continuing communication. 2. The wireless network includes a network management device connected to any one of the plurality of communication nodes and managing an overall operation of the wireless network. When the signal error rate of the system wireless transmission line exceeds a predetermined threshold, this is detected as a line abnormality and notified to the network management device, and the network management device transmits a line to the standby system wireless transmission line. 2. The wireless communication method according to claim 1, wherein the wireless communication path is switched from the working wireless transmission path to the standby wireless transmission path on condition that no abnormality occurs. 3. The communication node detects that a signal error rate of the working wireless transmission line exceeds a predetermined threshold as a line abnormality, and detects a line abnormality in the working wireless transmission line. 2. The wireless communication method according to claim 1, wherein the wireless communication path is switched from the working wireless transmission path to the standby wireless transmission path on the condition that no such transmission has occurred. 4. A wireless communication apparatus in a wireless communication network in which a plurality of communication nodes each accommodating one or a plurality of terminals are connected in a ring by an active wireless transmission line and a standby wireless transmission line having different transmission directions. A wireless communication apparatus, wherein the transmission capacity of the standby wireless transmission path is set smaller than the transmission capacity of the working wireless transmission path. 5. A network management device connected to any one of the plurality of communication nodes and managing an overall operation of the wireless network, the network management device comprising: When a notification of a line abnormality of the working wireless transmission line is received from any one of the communication nodes, the working wireless transmission line is provided on the condition that no line abnormality has occurred in the working wireless transmission line. 5. The wireless communication apparatus according to claim 4, further comprising a line switching unit for switching from a wireless communication path to the standby wireless transmission path. 6. The communication node comprising: a line abnormality detecting unit that detects a signal error rate of the working radio transmission line as a line abnormality when the signal error rate exceeds a predetermined threshold value; When a line abnormality of the working wireless transmission line is detected, a line that switches from the working wireless transmission line to the standby wireless transmission line on the condition that no line abnormality has occurred in the working wireless transmission line. The wireless communication device according to claim 4, further comprising a switching unit.