JP3730950B2 - Digital radio equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention is suitable for a digital wireless device, particularly when a wireless circuit is incorporated into an existing wired network provided with a monitoring control device that switches a signal transmission route when an input data disconnection failure caused by a cable disconnection continues for a certain time. The present invention relates to a digital radio apparatus.
[0002]
[Prior art]
When a line is expanded in an existing network of a wired network constructed by a wired device, a wireless line may be newly introduced into a part of the line to be expanded due to the installation environment of the user. For example, in the ring network shown in FIG. 4, the stations 101, 102, 103, 104, and 105 are connected by a wired line, and this time, a wireless line is introduced to one line between the stations 101 and 105. is there.
[0003]
The data transmission route between the stations 101, 102, 103, 104, and 105 is duplexed with an existing wired line so that data can be transmitted in two directions of “A” and “B”. The directions “a” and “b” are usually route-selected with one of the directions as the main and the other as the slave. A network monitoring control device 100 is connected to the station 104 to perform monitoring of data transmission status and route switching control in order to maintain desired data transmission quality.
[0004]
In FIG. 4, it is assumed that a station 101 and a station 105 are connected by a wired line and initially data is transmitted through a route “A”. At this time, the data transmission status monitoring data (hereinafter referred to as “status information”) is also transmitted to the network monitoring control device 100 through the route “a”. If a cable disconnection failure occurs between the stations 101 and 105, the network monitoring control device 100 cannot receive status information from the stations 101, 102, and 103. If this state lasts for a preset time, the network monitoring and control device 100 determines that the cable disconnection failure has occurred, determines that data transmission is impossible on the current data transmission route “A”, and sets the status on the spare “A” route. Transmission route switching control is performed so that information can be transmitted. The above is the operation of line switching control in a wired network constructed with wired lines.
[0005]
FIG. 5 shows one line connecting two stations extracted from FIG. FIG. 5A shows a case where the wire station M1 and the wire station M2 are connected by wire and data is transmitted in the direction from the wire station M1 to the wire station M2. Indicates that a cable disconnection failure has occurred. In such a case, data transmission can be continued without any problem by the above-described transmission route switching control. The “conventional” column in the upper “wired line” of FIG. 6 collectively displays the above results.
[0006]
As shown in FIG. 5B, when a wireless line is introduced by providing a wireless station R1 and a wireless station R2 between the wired station M1 and the wired station M2, the input data interruption at the point C is a cable on the wired line. Measures similar to the above are sufficient.
[0007]
When a cable disconnection failure occurs at point A, the radio station R1 fixes all data output to the opposite radio station R2 to “1”, modulates it, converts it to a radio signal, and transmits it. This all “1” signal is detected as an alarm in the radio station R2, and the radio station R2 can recognize that the input data disconnection state of the radio station R1 has occurred.
[0008]
However, the radio station R2 outputs the data fixed to “1” including the status information and the route switching control data (hereinafter referred to as “all“ 1 ”data”) as it is to the wired station M2. For this reason, the wired station M2 cannot detect the input data disconnection state, and the above-described data transmission state monitoring becomes impossible and the route switching control becomes impossible. Therefore, erroneous control such as recognizing an incorrect state or executing an incorrect route switching control occurs.
[0009]
Now, in the wireless communication section at point B, a failure may occur due to deterioration of the reception level of the wireless signal of the wireless device due to weather conditions such as fading and rain attenuation. This radio-specific failure mode is a radio-specific data error in which a reproduction error occurs when data demodulated from a received radio signal is reproduced when the reception level of the radio signal decreases due to weather conditions.
[0010]
For example, when “1” data was transmitted on the transmitting side and “0” data was accidentally reproduced on the receiving side, or when “0” data was transmitted on the transmitting side, This is a case where “1” data is reproduced. Error correction is performed for such a data reproduction error, but if the error cannot be corrected, data including the error is transmitted to a subsequent device (wired device or monitoring control device). In this case, the wireless station R2 receives the error data and sends the error data as it is to the wired station M2. Here, if the error data is for status information or route switching control data, the above-described erroneous control occurs.
[0011]
When the input level of radio reception further decreases, it becomes impossible to identify a radio frame unit which is a data multiplexing period, and a frame asynchronous failure occurs. Asynchronous frame failure is a redundant bit for error correction necessary to correct a reproduction error, a signal for a meeting line between radio facing devices, a parity bit for monitoring data quality of a transmission line, or additional information such as status information Is a failure in which a multiplexing cycle (frame unit) in which the signal is multiplexed with the main signal data cannot be found. The main signal data refers to data that is an original communication target.
[0012]
Conventionally, when a frame asynchronous failure is detected by the radio station R2, the radio apparatus of the radio station R2 operates using an internal clock and outputs all “1” data. For this reason, the wired station M2 has no response from the monitoring target, and it can be seen that the current transmission route is in an abnormal state, but the input data disconnection state cannot be detected. Therefore, when the abnormal state of the opposite device due to the detection of the input data disconnection state is received as the state information, the monitoring control device that performs transmission route switching cannot perform normal route switching.
[0013]
In addition, when an SDH-compliant wireless device that conforms to the ITU-T (TELECOMMUNICATION STANDARDIZATION SECTOR of INTERNATIONAL TELECOMMUNICATION UNION) recommendation is introduced to the wired network, frame synchronization pattern data peculiar to wireless communication is detected for frame asynchronous failures. After synchronization pull-in, the possibility of a pseudo pull-in phenomenon that the input data is pulled to the wrong data position by reducing the number of mismatches that determine out-of-frame synchronization by comparing the frame sync pattern data with the input data for a certain period of time. (See, for example, Patent Document 1).
[0014]
In some cases, detection is performed under LOF (Loss Of Frame) determination conditions using A1 and A2 bytes described in the ITU-T recommendation instead of the frame synchronization pattern, and synchronous / asynchronous determination is performed based on the result of detecting the LOF. (Refer nonpatent literature 1).
[0015]
In the case of a radio frame asynchronous failure, in the case of a radio device that does not support SDH, the data to the subsequent wired device or the monitoring control device is fixed to all “1” data (see Non-Patent Document 2). On the other hand, a radio apparatus corresponding to SDH newly generates an SDH data frame for the monitoring and control apparatus in the subsequent stage, and uses MS-AIS (multiplex section alarm indication signal) as signaling notifying that a failure has occurred in the radio transmission path. ) Is transmitted (see Non-Patent Document 3). Also in this case, the supervisory control device receives all “1” data, and thus enters an erroneous control state. The “conventional” column in the “wireless line” in the lower part of FIG. 6 collectively displays the above results.
[0016]
[Patent Document 1]
JP-A-5-14336 (first to third pages, FIG. 1)
[Non-Patent Document 1]
ITU-T recommendation G783
[Non-Patent Document 2]
ITU-T recommendation G775
[Non-Patent Document 3]
ITU-T recommendation G707
[0017]
[Problems to be solved by the invention]
As described above, the failure mode that occurs in the wired network is a cable disconnection failure, and the cable disconnection failure is detected in the form of disconnection of input data to the monitoring control device. However, since radio-specific failures occur due to weather conditions, the degradation of data quality may be maintained for a certain period of time due to a data reproduction error demodulated from a signal with a reduced radio reception level. There may be an asynchronous state.
[0018]
Therefore, in the case of a wireless line, since the form of output data caused by a wireless-specific failure such as a data error failure or a wireless frame asynchronous failure is different from that at the time of a cable disconnection failure, It has been developed so that it can be monitored only in response to this, and there is a problem that transmission route switching control becomes impossible when a wireless data transmission line data error failure and a frame asynchronous failure are not taken into consideration.
[0019]
That is, in a state where the quality deterioration state of the input data to the monitoring control device continues, an error also occurs in the state information multiplexed and transmitted to the wireless data. For this reason, normal monitoring may become impossible. In a state where radio frame asynchrony occurs, all “1” data is input from the wireless device to the monitoring control device, and data from the monitoring target is not normally input, so that monitoring is disabled.
[0020]
As a result, when a wireless line is introduced into a part of a wired network, a significant correction of the monitoring and control device is performed for a line failure such as deterioration of a data error rate specific to a wireless transmission line or asynchronous frame asynchronousness, or There is a problem that it is necessary to replace the supervisory control device adapted to the line failure.
[0021]
Therefore, an object of the present invention is to incorporate a wireless line into a wired network in which a monitoring control device that switches a signal transmission route under a condition that the input data disconnection caused by the cable disconnection as a failure of the wired network continues for a certain time is already installed. To provide a wireless device that can cope with the occurrence of a radio-specific failure by switching to a backup route in the same manner as a wired cable disconnection without requiring modification or replacement of the monitoring and control device. is there.
[0024]
The digital radio apparatus of the present invention In a digital wireless device incorporated in an existing wired network provided with a monitoring and control device that switches the signal transmission route when the input data disconnection failure caused by the cable disconnection continues for a certain time, the input data disconnection failure from the wired device is detected. Means for detecting, means for transmitting the input data failure information to the opposing digital radio apparatus, means for detecting the input failure information from the received signal, and counting the time during which the input failure state is continued Means for detecting that the counting time has exceeded a preset duration, and means for stopping data output from the digital radio apparatus when the input interruption failure state exceeds the duration. The monitoring control device switches the signal transmission route when the data output is stopped.
[0025]
More specifically, the digital wireless device of the present invention is an existing wired network provided with a monitoring control device (100 in FIG. 4) for switching a signal transmission route when an input data disconnection failure caused by a cable disconnection continues for a certain time. In the digital wireless device incorporated in the wireless signal transmission side, on the wireless signal transmission side, an input interruption detection circuit (10 in FIG. 1) for detecting an interruption in the input data from the wired device, and input data interruption information are multiplexed with the main signal data. And a multiplexing circuit (11 in FIG. 1) for transmitting to the opposing digital radio apparatus via a radio transmission path, and a signal for detecting input data disconnection failure information from the multiplexed signal on the radio signal receiving side A separation circuit (12 in FIG. 1), a first counting circuit (14 in FIG. 1) that counts the time during which the input data disconnection failure state continues according to the detected input data disconnection failure information, A first duration monitoring circuit (16 in FIG. 1) that detects that the power data failure condition has exceeded a preset duration threshold, and an error rate of data errors occurring in the wireless transmission path is preset. An error rate detection circuit (13 in FIG. 1) for detecting whether the error rate threshold is exceeded, and a second counting circuit (15 in FIG. 1) for counting the time during which the detected error rate threshold is exceeded. ), A second duration monitoring circuit (17 in FIG. 1) for detecting that the state exceeding the error rate threshold exceeds a preset duration threshold, and the first duration monitoring circuit or the second continuation A data conversion circuit (19 in FIG. 1) for stopping the data output from the digital wireless device by the output from the time monitoring circuit, and the monitoring control device switches the signal transmission route by stopping the data output. And
[0026]
In addition, the digital wireless device of the present invention is a monitoring controller that switches the signal transmission route when the input data disconnection failure caused by the cable disconnection continues for a certain time. In a digital wireless device incorporated in an existing wired network provided with a monitoring control device (100 in FIG. 4) that performs switching, an input interruption that detects a interruption in the input data from the wired device is detected on the wireless signal transmission side. A detection circuit (10 in FIG. 2), and a multiplexing circuit (11 in FIG. 2) that multiplexes the input data disconnection failure information with the main signal data and transmits the information to the opposing digital wireless device via a wireless transmission path, The signal receiving side includes a signal separation circuit (12 in FIG. 2) for detecting input data disconnection failure information from the multiplexed signal, and the detected input data disconnection. A first counting circuit (14 in FIG. 2) that counts the time during which the input data disconnection failure state is continued based on harm information, and detects that the input data failure failure state has exceeded a preset duration threshold value. A first duration monitoring circuit (16 in FIG. 2), a frame asynchronous determination circuit (20 in FIG. 2) that determines that the frame asynchronous pattern error state occurring in the wireless transmission path is frame asynchronous, and the frame asynchronous state continues. A second counting circuit (15 in FIG. 2) that counts a certain time, a second duration monitoring circuit (17 in FIG. 2) that detects that the counted time exceeds a preset duration threshold, A data conversion circuit (19 in FIG. 2) for stopping the data output from the digital radio apparatus by the output from the first duration monitoring circuit or the second duration monitoring circuit; Visual control device and performs the switching of the signal transmission route.
[0027]
Furthermore, when an input interruption detection result is input from the input interruption detection circuit, a frame synchronization pattern conversion circuit that converts the frame synchronization pattern into random data or a fixed pattern different from normal and outputs it to the multiplexing circuit as input data interruption failure information. It may be provided.
[0028]
In the present invention, when a failure peculiar to the radio generated in the radio transmission path is detected by reception of the digital radio apparatus, data is output from the digital radio apparatus to a subsequent apparatus (wired apparatus or monitoring control apparatus). Is configured in the same way as the data disconnection state that occurs at the time of a cable disconnection failure, so that even if a radio-specific failure occurs in the added wireless line, the redundant data transmission path remains in the same state as the conventional monitoring control device. Switch to the root.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0030]
In the ring network shown in FIG. 4, the stations 101, 102, 103, 104, and 105 are connected by a wired line as described above, and data transmission between the stations 101, 102, 103, 104, and 105 is performed. The route is duplexed with an existing wired line so that data can be transmitted in two directions, A and B. A network monitoring control device 100 is connected to the station 104 to perform monitoring of data transmission status and route switching control in order to maintain desired data transmission quality.
[0031]
This time, in such an existing ring network, a part of the wired network between the stations 101 and 105 is replaced with a wireless line to reconstruct the ring network. One wireless connection line is extracted and shown in FIG.
[0032]
[Configuration of Example]
FIG. 1 is a block diagram showing a first embodiment of a digital radio apparatus according to the present invention. In this embodiment, input data is interrupted at point A between the wired station M1 and the wireless station R1, or data peculiar to wireless at the point B of the wireless transmission pole connecting the transmitting-side wireless station R1 and the receiving-side wireless station R2. Even if an error occurs, it can be dealt with by selecting a backup route, as in the case of a cable disconnection failure in a wired transmission line.
[0033]
Regardless of whether it is a wired station or a wireless station, in general, the status information j1 such as the line quality and alarm detected by the devices constituting the communication network is the main signal data transmitted from the device as well as the input data disconnection information. And transmitted to the monitoring control apparatus 100.
[0034]
The supervisory control device 100 separates and analyzes the state information j1 multiplexed on the main signal data, and detects a transmission path in which a line failure has occurred. That is, the supervisory control device 100 analyzes the link establishment state and the state information about which line of the monitoring target has failed, and determines whether a failure has been detected in the previous line from the state signal of the device that has established the link. Check. As a result, the route selection is switched from the “A” direction to the “A” direction so as not to use a route including a transmission path for which a link has not been established. The link establishment can be determined from the status information and the response status when collecting the status sequentially.
[0035]
The digital radio apparatus according to the present embodiment is provided in each of the radio stations R1 and R2 in FIG. 5B, and transmits and receives data via a radio line to form a part of the ring network as shown in FIG. FIG. 1A shows a transmission side circuit, and FIG. 1B shows a reception side circuit. When data is transmitted from the radio station R1 to the radio station R2 as shown in FIG. 5B, the transmission side circuit functions in the radio station R1 and the reception side circuit functions in the radio station R2.
[0036]
The transmission side circuit of FIG. 1A includes an input disconnection detection circuit 10 and a multiplexing circuit 11. The input disconnection detection circuit 10 detects input data disconnection (input data disconnection at point A in FIG. 5B). This detection condition is that, for example, the input level falls below a threshold value as described in the LOS (Loss Of Signal) detection condition of ITU-T recommendation G775. The input disconnection detection result is sent to the multiplexing circuit 11 as input disconnection failure information. The multiplexing circuit 11 multiplexes and modulates main signal data, which is the original communication target data, and state information, and transmits the multiplexed data as radio transmission data to the opposite radio station R2.
[0037]
In the digital radio apparatus of radio station R2, the received signal is demodulated and converted into a digital signal, and synchronization is established by finding a frame synchronization pattern for the demodulated data. Further, the digital radio apparatus of the radio station R2 performs error detection and error correction on the demodulated and synchronized digital signal. This error refers to an error at point B in FIG.
[0038]
1B includes a signal separation circuit 12, an error rate detection circuit 13, two counters 14 and 15, two duration monitoring circuits 16 and 17, an OR circuit 18, and data conversion. Circuit 19.
[0039]
The signal separation circuit 12 detects input disconnection failure information from the demodulated digital signal whose synchronization is established, and sends it to the counter 14. The counter 14 counts the time t0 during which the input data disconnection failure state continues based on the input disconnection failure information. On the other hand, the error rate detection circuit 13 detects whether or not the data error r1 that could not be corrected by the error correction exceeded a preset data error rate threshold value r1s, and sends it to the counter 15. The counter 15 counts the time t1 during which the state where the data error exceeds the data error rate threshold value r1s continues.
[0040]
The duration monitoring circuit 16 compares the time t0 counted by the counter 14 with a preset duration threshold t0s. The duration monitoring circuit 17 compares the time t1 counted by the counter 15 with a preset duration threshold t1s. The OR circuit 18 synthesizes the comparison results in the duration monitoring circuit 16 and the duration monitoring circuit 17 and sends them to the data conversion circuit 19.
[0041]
The data conversion circuit 19 normally outputs the demodulated data as transmission data to the wired station or the monitoring control device. However, if t0> t0s or t1> t1s, the data to be output is stopped for a preset time t5. As described above, it is necessary to continue for a certain period of time (t0s, t1s) to stop the data. As mentioned above, radio-specific failures are caused by weather conditions, so they are demodulated from signals with low radio reception levels. The data quality deterioration state due to a data reproduction error may be maintained for a certain period of time, or may suddenly become a radio frame asynchronous state, so that the determination is waited for.
[0042]
[Operation of the embodiment]
Next, the operation of the first embodiment will be described. A data error rate threshold r1s is set in the error rate detection circuit 13 in FIG. 1, a duration threshold t0s is set in the duration monitoring circuit 16, and a duration threshold t1s is set in the duration monitoring circuit 17.
[0043]
In FIG. 4, it is assumed that the main signal data is transmitted through the route “A” and the status information is also transmitted to the monitoring control device 100 through the route “A”. When the input data disconnection occurs between the wired station M1 and the wired station M2, when the connection is made with a cable (FIG. 5A), it is a cable disconnection failure. To the “A” route. As shown in FIG. 5B, the same applies to the case where the input data disconnection occurs at the point C between the wireless station R2 and the wired station M2. These controls are displayed in the “present invention” column in the upper “wired line” in FIG. 6 and the “present invention” column for the failure occurrence point “point C” in the lower “wireless line”.
[0044]
When a failure due to cable disconnection occurs at point A between the wired station M1 and the wireless station R1, the digital wireless device of the wireless station R1 located at the transmission end of the wireless transmission path detects the input data disconnection (LOS), The input data disconnection information is multiplexed in the signal data. In the digital radio apparatus of the radio station R2 located at the receiving end, the data separation information of the opposite side is extracted from the received data multiplexed by the signal separation circuit 12, and the time t0 counted by the counter 14 is set in advance. The duration monitoring circuit 16 determines that the duration is longer than the time threshold t0s. When the input data disconnection failure has continued for the duration threshold value t0s or more, when the determination result is input via the OR circuit 18, the data conversion circuit 19 controls to stop the output data to the wired station M2. I do. This control is displayed in the “present invention” column for the failure occurrence point “A point” in the “wireless line” in the lower part of FIG.
[0045]
Next, when a transmission path failure occurs in the wireless line (point B in FIG. 5B), a data error failure or a frame asynchronous failure is detected on the receiving side of the digital wireless device. From the direction, since data on the transmission path does not arrive at the monitoring control device 100 from a station farther away from the wireless device of the wireless station R1, the state of the device cannot be monitored. The failure at point B is peculiar to radio, and is a failure in which a data error occurs due to a decrease in the radio input level of the radio station R2, and further frame asynchrony is detected. This data error causes the status information j from the stations 101, 102, 103 to be incorrect.
[0046]
In the digital radio apparatus of the receiving end radio station R2, the error rate detection circuit 13 detects the data error rate r1. The data error rate r1 is detected by calculating the parity for the data at the sending end, multiplexing the corresponding calculation result with the data, and performing the same parity calculation at the receiving end as for the sending end on the data containing errors. This can be detected by comparing the result obtained with the result calculated at the sending end separated from the data. Further, when error correction is performed, detection can also be made from the number of corrections at the time of error correction.
[0047]
Data of the data error rate r1 is input to the monitoring control device 100. The state information j separated from this data is also the error rate r1. On the other hand, the monitoring control apparatus 100 separates and extracts information (for example, input data disconnection information detected by the wired station M2) from the monitoring target station from the status information j for each item. Furthermore, the monitoring and control apparatus 100 has a function of protecting against errors in the separated and extracted state information j (for example, majority decision or continuous detection of the same value).
[0048]
This protection function has an effect that information from the monitoring target station can be correctly reproduced if the error rate r1 of the input data is equal to or less than the error rate threshold r2 unique to the monitoring control device 100 (r1 <= r2). Conversely, when the error rate r1 of the input data exceeds the error rate threshold r2 (r1> r2), information from the monitoring target station is erroneously recognized, resulting in erroneous control in route selection. Therefore, the error rate detection circuit 13 has a data error rate threshold value r1s (r1s <r2) less than the error rate threshold value r2.
[0049]
The counter 15 counts a time t1 during which the state in which the data error rate r1 is deteriorated from the data error rate threshold value r1s (r1> r1s) continues. The duration monitoring circuit 17 monitors whether the time t1 is longer than the duration threshold t1s. This is to prevent the data output from being controlled when the data error rate r1 deteriorates from the data error rate threshold value r1s only instantaneously (time less than t1s) due to radio-specific selectivity fading. When the time t1 at which the data error rate r1 is equal to or greater than the data error rate threshold r1s continues for the duration threshold value t1s or longer, when the result is input via the OR circuit 18, the data conversion circuit 19 sets in advance. Output data disconnection control is performed during the control time t5. The control time t5 is a time sufficient for the monitoring and control apparatus 100 to determine the occurrence of a line failure and to switch to the backup route.
[0050]
Control of output data disconnection can be realized by stopping the operation of an output device such as an optical device that outputs data from the digital radio apparatus. Specifically, the power supply to the output device is turned off, or the output cutoff control function of the output device is used.
[0051]
As a result of the output data disconnection control of the radio station R2, the input disconnection failure information detected by the wired station M2 is included in the state information and multiplexed with the main signal data and transmitted. When the input disconnection failure information is input, the supervisory control device 100 knows that this is due to a transmission path failure in the wireless line (point B in FIG. 5B), and selects the backup route. This control is displayed in the column of “present invention” for the failure location “point B” and “data error” in the lower “wireless line” of FIG.
[0052]
In this way, when a data error occurs at point B in FIG. 5B, the same phenomenon as the failure state monitored by the monitoring control device 100 can be obtained, so that it is possible to switch to a normal route. Become. Therefore, even when a wireless line is introduced into an existing wired network, the network monitoring operation can be performed by the dedicated monitoring control device 100 without modifying or replacing the monitoring control device 100.
[0053]
The same applies to the case where data was initially transmitted in the “A” direction. In this case, it goes without saying that the transmission side circuit of FIG. 1A functions in the radio station R1, and the reception side circuit of FIG. 1B functions in the radio station R2.
[0054]
[Other embodiments]
FIG. 2 is a block diagram showing a second embodiment of the digital radio apparatus of the present invention. In this embodiment, a frame asynchronous determination circuit 20 is provided instead of the error rate detection circuit 13 in the first embodiment shown in FIG. Other configurations are not different from those of the first embodiment. Components having the same reference numerals in FIGS. 2 and 1 have the same functions.
[0055]
As described above, when the data error further increases due to fading on the wireless transmission path or an increase in rainfall, an error may occur in the frame asynchronous pattern that is a part of the additional information multiplexed at the transmission end. The frame asynchronous determination circuit 20 determines that such an error state of the frame asynchronous pattern is frame asynchronous.
[0056]
In frame asynchronous determination, a determination protection condition can be set. The determination protection condition is, for example, that the bits constituting the frame synchronization pattern are determined to be frame asynchronous when there is a k-bit continuous error or an n-bit error in m bits. Originally, in a digital radio apparatus that transmits a continuous signal with stable frequency accuracy, reception timing does not easily shift due to a change in the state of the radio transmission path. Therefore, the above-described determination protection condition can be set as a condition for starting re-drawing that means re-establishment of reception timing. In this case, the frame asynchronous determination circuit 20 determines that the frame is asynchronous when it deviates from the determination protection condition from the state where the frame synchronization is established, and performs redrawing.
[0057]
The counter 15 counts the time t3 during which the frame asynchronous state continues. The duration monitoring circuit 17 detects that this counting time has exceeded a preset duration threshold t3s. Then, the data conversion circuit 19 stops the data output from the digital radio apparatus for a preset time t5. Subsequent processing does not differ from the first embodiment. This control is displayed in the column of “present invention” for the failure occurrence point “point B” and “frame asynchronous” in the lower “wireless line” of FIG.
[0058]
In this way, when a frame asynchronous failure occurs at point B in FIG. 5 (B), the failure can be made the same phenomenon as the failure state monitored by the monitoring control device 100, so it is possible to switch to a normal route. become. Therefore, even when a wireless line is introduced into an existing wired network, the network monitoring operation can be performed by the dedicated monitoring control device 100 without modifying or replacing the monitoring control device 100.
[0059]
The same applies to the case where data was initially transmitted in the “A” direction. In this case, it goes without saying that the transmission side circuit of FIG. 1A functions in the radio station R1, and the reception side circuit of FIG. 1B functions in the radio station R2.
[0060]
By the way, in the SDH-compatible digital radio apparatus that wirelessly transmits SDH data recommended by ITU-T, the SDH frame synchronization pattern is defined as A1, A2 bytes (F628 hex) separately from the frame synchronization signal, and further, the B1 byte Is defined as a parity byte for data quality monitoring. In data transmission on the wireless transmission path, A1 and A2 are multiplexed and transmitted by the digital wireless device at the sending end, and SDH frame synchronization is established by detecting the A1 and A2 bytes at the receiving end. After establishing the SDH frame synchronization, the data quality of the wireless transmission path is determined by the error of the B1 parity calculation result.
[0061]
Further, since the subsequent wired device needs to be a device compatible with SDH, data transmitted from the digital wireless device at the receiving end also transmits / receives data subjected to SDH framing. Therefore, the wired device also establishes SDH frame synchronization and further determines the data quality by calculating B1 bytes.
[0062]
In the case of an SDH-compatible wired device, instead of detecting an input data disconnection at the time of a cable disconnection failure, a route may be selected when an SDH frame asynchronous failure in which A1 and A2 bytes cannot be detected continues. In this case, instead of the SDH-compatible digital wireless device stopping output data to the subsequent device, route selection switching is executed if the A1 and A2 bytes can be output with a random pattern or a fixed pattern that cannot establish SDH frame synchronization. it can.
[0063]
Focusing on this point, the third embodiment can be realized. The third embodiment is applied only to an SDH-compatible device, and its configuration is not different from that in FIG. 1 or FIG. Instead of stopping output data, the data conversion circuit 19 outputs a random pattern or a fixed pattern for the A1 and A2 bytes so that SDH frame synchronization cannot be established.
[0064]
FIG. 3 is a block diagram showing a fourth embodiment of the digital radio apparatus of the present invention. In this embodiment, a frame synchronization pattern conversion circuit 30 is provided in the transmission side circuit (FIG. 2A) of the second embodiment, and other configurations are the same as those of the second embodiment. Components having the same reference numerals in FIGS. 3 and 2 have the same functions.
[0065]
When the input interruption detection result is input from the input interruption detection circuit 10, the frame synchronization pattern conversion circuit 30 converts the frame synchronization pattern into random data or a fixed pattern different from normal. The multiplexing circuit 11 multiplexes such random data or a fixed pattern with input data and outputs it as transmission data. For this reason, frame synchronization cannot be established at the opposite receiving end, and as a result, the data output to the subsequent apparatus is controlled to stop.
[0066]
In addition, the 5th Example which applied the 4th Example to the SDH corresponding | compatible apparatus is realizable. The fifth embodiment detects the input LOS (Loss of signal) at the transmitting end in order to stop the data output from the wireless device to the subsequent device when the failure determination in the monitoring and control device 100 is performed by the continuation of the LOF. The frame synchronization pattern conversion circuit 30 has a function of converting A1 and A2 transmitted to the receiving end into a random pattern or a fixed pattern in which SDH frame synchronization cannot be established.
[0067]
As a result, the SDH frame synchronization cannot be established for the data including the SDH frame demodulated and reproduced by the digital radio device at the receiving end, and it is determined that the frame is asynchronous and the output data is stopped. .
[0068]
The sixth embodiment in which the first embodiment and the second embodiment are combined, that is, the error rate detection circuit 13 and the frame asynchronous determination circuit 20 coexist can be easily realized. In this embodiment, it is possible to cope with both data errors and frame asynchronous failures in the wireless transmission path.
[0069]
【The invention's effect】
As described above, the digital radio apparatus according to the present invention is configured to be in the same state as the cable disconnection in the case of wired even when a radio-specific fault occurs, so that the input data disconnection fault caused by the cable disconnection is constant. When a wireless line is added to a wired network that already has a monitoring control device that switches the signal transmission route over time, it is not necessary to modify or replace the monitoring control device, making it easy to add a wireless line Have
[Brief description of the drawings]
FIG. 1 is a block diagram showing configurations of a transmission side (A) and a reception side (B) in a digital radio apparatus according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a transmitting side (A) and a receiving side (B) in a digital radio apparatus according to a second embodiment of the present invention.
FIG. 3 is a block diagram showing a configuration of a transmitting side (A) and a receiving side (B) in a digital radio apparatus according to a fourth embodiment of the present invention.
FIG. 4 is a diagram for explaining a general ring network;
FIG. 5 is a diagram for explaining operations in a wired line section (A) and a wireless line section (B) in FIG. 4;
FIG. 6 is a diagram showing the control in the prior art and the present invention for each failure location for a wired line and a wireless line.
[Explanation of symbols]
10 Input data break detection circuit
11 Multiplexing circuit
12 Signal separation circuit
13 Error rate detection circuit
14 counter
15 counter
16 Duration monitoring circuit
17 Duration monitoring circuit
18 OR circuit
19 Data conversion circuit
20 frame asynchronous decision circuit
30 frame synchronization pattern conversion circuit
100 Network monitoring and control device
101-105 stations
M1, M2 cable station
R1, R2 radio stations

Claims (5)

In a digital wireless device incorporated in an existing wired network provided with a monitoring control device for switching a signal transmission route when an input data disconnection failure caused by a cable disconnection continues for a certain time,
Means for detecting disconnection failure of input data from a wired device;
Means for transmitting the input data disconnection failure information to the opposing digital wireless device;
Means for detecting the input disconnection failure information from the received signal;
Means for counting the time during which the input disconnection failure state continues;
Means for detecting that the counting time exceeds a preset duration;
Means for stopping data output from the digital wireless device when the input disconnection fault state exceeds a duration time;
The digital radio apparatus according to claim 1, wherein the monitoring control apparatus switches the signal transmission route when the data output is stopped. In a digital wireless device incorporated in an existing wired network provided with a monitoring control device for switching a signal transmission route when an input data disconnection failure caused by a cable disconnection continues for a certain time,
On the wireless signal transmission side,
An input disconnection detection circuit for detecting a disconnection failure of input data from a wired device;
A multiplexing circuit that multiplexes the input data disconnection failure information with the main signal data and transmits the multiplexed data to the opposing digital wireless device via a wireless transmission path;
On the wireless signal receiver side,
A signal separation circuit for detecting input data failure information from the multiplexed signal;
A first counting circuit for counting a time during which an input data failure condition is continued according to the detected input data failure information;
A first duration monitoring circuit for detecting that the input data disconnection fault state exceeds a preset duration threshold;
An error rate detection circuit for detecting whether an error rate of a data error occurring in a wireless transmission path exceeds a preset error rate threshold;
A second counting circuit that counts the time during which the detected error rate threshold is exceeded;
A second duration monitoring circuit for detecting that a state exceeding the error rate threshold exceeds a preset duration threshold;
A data conversion circuit for stopping data output from the digital wireless device by an output from the first duration monitoring circuit or the second duration monitoring circuit;
The digital radio apparatus according to claim 1, wherein the monitoring control apparatus switches the signal transmission route when the data output is stopped. In a digital wireless device incorporated in an existing wired network provided with a monitoring control device for switching a signal transmission route when an input data disconnection failure caused by a cable disconnection continues for a certain time,
On the wireless signal transmission side,
An input disconnection detection circuit for detecting a disconnection failure of input data from a wired device;
A multiplexing circuit that multiplexes the input data disconnection failure information with the main signal data and transmits the multiplexed data to the opposing digital wireless device via a wireless transmission path;
On the wireless signal receiver side,
A signal separation circuit for detecting input data failure information from the multiplexed signal;
A first counting circuit for counting a time during which an input data failure condition is continued according to the detected input data failure information;
A first duration monitoring circuit for detecting that the input data disconnection fault state exceeds a preset duration threshold;
A frame asynchronous determination circuit that determines that an error state of a frame asynchronous pattern generated in a wireless transmission path is frame asynchronous;
A second counting circuit for counting a time during which the frame asynchronous state continues;
A second duration monitoring circuit for detecting that the counted time exceeds a preset duration threshold;
A data conversion circuit for stopping data output from the digital wireless device by an output from the first duration monitoring circuit or the second duration monitoring circuit;
The digital radio apparatus according to claim 1, wherein the monitoring control apparatus switches the signal transmission route when the data output is stopped. A frame synchronization pattern conversion circuit for converting a frame synchronization pattern into random data or a fixed pattern different from normal and outputting the input data disconnection failure information to the multiplexing circuit when an input interruption detection result is input from the input interruption detection circuit 4. The digital radio apparatus according to claim 2 , wherein the digital radio apparatus is provided. In the SDH-compliant device compliant with the ITU-T recommendation, the data conversion circuit outputs a random pattern or a fixed pattern such that SDH frame synchronization cannot be established for the A1 and A2 bytes instead of stopping the output data. The digital radio apparatus according to any one of claims 2 to 4 , wherein

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