JP3337015B2 - Wireless local loop system and its fault detection / reporting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless local loop system and a method of detecting and reporting a failure thereof, and more particularly to a fixed subscriber terminal (SU) from a wireless base station.
r Unit) is connected wirelessly, and the subscriber terminal and the subscriber telephone organization are wired cables (subscriber line)
Wireless local loop (WLL: Wireless)
The present invention relates to an ess Local Loop) system and a method for detecting and reporting a failure thereof.

[0002]

2. Description of the Related Art A conventional WLL system of this type and a method of detecting a failure thereof will be described with reference to the drawings.

FIG. 6 is a schematic diagram showing an example of a conventional WLL system, FIG. 7 is a diagram for explaining a first test in the conventional WLL system shown in FIG. 6, and FIG. 8 is a conventional WLL system shown in FIG.
FIG. 9 is a diagram illustrating a second test in the LL system.

Referring to FIGS. 6, 7 and 8, this conventional WLL system and its test method are disclosed in
No. 5444 is disclosed, and in the case of the first test, a control signal of the base station controller (BSC) 101 or a signal of a communication channel is output from a desired port. The LE side I of the base station controller (BSC) 101
The / O unit 133 has a plurality of ports for transmitting and receiving call signals and the like, one of which is a local exchange (LE) 11
1 and the other one is connected to the maintenance console 103. The LE-side I / O unit 133 includes an analog switch 151. The analog switch 151 is
It outputs a call signal and the like under the control of the control unit 120.

[0005] In the first test, a communication path signal or the like is output to, for example, the maintenance console 103. Then, the maintenance console 103 analyzes the call signal and the like to check the normality of the call path. In the first test, a call signal or the like can be output to another arbitrary device.

[0006] Next, in the case of the second test, a signal from one subscriber terminal (SU) is transferred to another desired subscriber terminal (SU), and whether a signal can be transmitted and received between them is determined. The normality of the communication path is checked based on the above.

When the base station controller (BSC) 101 receives a signal (for example, SETUP) from the base station (BTS) 102 in a state where the operation mode is off-line and the second test is set as the test type, It works as follows. That is, the control unit 120 transmits the local exchange (L) received by the LE side I / O unit 133 from the exchange unit 131.
E) The analog switch 151 is controlled so that the signal to be transmitted to the 111 is looped back to the exchange 131. The control unit 120 also controls the switching unit 131 to transfer the loop-backed signal to a desired subscriber terminal (SU).
Control.

[0008]

In this conventional WLL system, the communication path test is performed by setting the operation mode to the offline mode. Therefore, the communication path test cannot be performed in the online mode. There is a problem.

In the test in the off-line mode, the telephone number of the inspection subscriber telephone is first input from the maintenance terminal of the maintenance person to test the communication path to the subscriber terminal. The user has to input the telephone number of the subscriber telephone set to be inspected for each test and perform the test, and there is a problem that the test takes time.

Further, in the test mode in this conventional example,
This is a test between the subscriber terminal and the base station controller, and there is a problem that a test on the wired line between the subscriber terminal and the subscriber telephone organization is not performed.

[0011]

According to the wireless local loop system of the present invention, each subscriber terminal is connected to a subscriber telephone via a subscriber line, and each subscriber terminal is connected via a wireless line. Connected to a wireless base station, the wireless base station connected to a wireless control device via a first wired line, and the wireless control device connected to a telephone exchange connected to a public telephone network via a second wired line. In the wireless local loop system, each of the subscriber terminals has a line failure detecting means for detecting a failure of a subscriber line with the subscriber telephone to which the subscriber terminal is connected. A receiving message is received from the telephone exchange, and the called terminal is connected via the radio base station to a subscriber terminal connected to a subscriber telephone corresponding to the subscriber number stored in the receiving message. When a failure of the subscriber line connected to the subscriber terminal is received via the radio base station after transmitting the message, a notification unit for reporting to the maintenance person that the subscriber line has failed is provided, The radio controller notifies the telephone exchange of the failure information of the subscriber line, and also notifies the maintenance terminal connected to the radio controller of the failure information of the subscriber line as the reporting means. The terminal has display means for displaying the fault information of the subscriber line, and the telephone exchange, upon receiving the fault information of the subscriber line from the preceding wireless control device, issues a call to a subscriber telephone connected to the subscriber line. An announcement device for transmitting a message indicating a failure of the subscriber line to the calling subscriber telephone set via the public telephone network, wherein the subscriber terminal DC-48V via line to the subscriber telephone set connected to the subscriber telephone set
A subscriber circuit having functions of power supply, ON / OFF-hook detection, ringing from a signal sound generation circuit and transmission of various tones, the signal sound generation circuit for generating the ringing and various tones, and an antenna A radio circuit that receives a digital radio signal from the radio base station and demodulates the analog signal into an analog signal, modulates an analog signal from the subscriber circuit into a digital radio signal, and transmits the signal. A failure detection circuit for detecting a failure of the subscriber circuit via a subscriber circuit, and transmitting the subscriber line information to the wireless circuit upon receiving a detection signal of failure detection of the subscriber line from the failure detection circuit. And a CPU for controlling the subscriber circuit, the wireless circuit, the signal tone generation circuit, and the failure detection circuit.

In the method for detecting and reporting a failure in a wireless local loop system according to the present invention, each subscriber terminal is connected to a subscriber telephone set via a subscriber line, and each subscriber terminal is connected via a wireless line. Connected to a wireless base station, the wireless base station connected to a wireless control device via a first wired line, and the wireless control device connected to a telephone exchange connected to a public telephone network via a second wired line. A wireless local loop system connected to a subscriber telephone connected to a subscriber telephone corresponding to a subscriber number stored in the incoming call message when the wireless control device receives an incoming call message from the telephone exchange. The subscriber terminal, which has transmitted to the terminal via the radio base station and received the incoming call message, tests the presence or absence of a failure of the connected subscriber line by the line failure detecting means. When a failure is detected, a failure message of the subscriber line is transmitted to the wireless control device via the wireless base station, and the wireless control device reports the failure of the subscriber line to a maintenance person via a reporting unit. Then, the radio control apparatus transmits a failure message of the subscriber line to the telephone exchange, and upon receiving the failure message of the subscriber line, the telephone exchange calls the subscriber telephone connected to the subscriber line. A message indicating that there is a failure in the subscriber line is transmitted from the announcement device to the calling subscriber telephone set via the public telephone network.

In the method for detecting and reporting a failure in a wireless local loop system according to the present invention, each subscriber terminal connects to a subscriber telephone set via a subscriber line, and each subscriber terminal connects via a wireless line. Connected to a wireless base station, the wireless base station connected to a wireless control device via a first wired line, and the wireless control device connected to a telephone exchange connected to a public telephone network via a second wired line. A wireless local loop system connected to a subscriber telephone connected to a subscriber telephone corresponding to a subscriber number stored in the incoming call message when the wireless control device receives an incoming call message from the telephone exchange. The subscriber terminal transmitting to the terminal via the radio base station and then receiving the incoming call message returns an incoming call response message via the radio base station, Receiving the incoming call response message, sends a radio communication channel assignment to the subscriber terminal via the radio base station, and then the subscriber terminal transmits the radio communication channel to the radio control device. After responding to the reception of the channel assignment, the radio control apparatus makes a ringing transmission request of the subscriber telephone to the subscriber terminal. Next, the subscriber terminal having received the ringing transmission request is connected to the line. The failure detecting means tests the presence or absence of a failure in the connected subscriber line, and when a failure is detected, transmits a failure message of the subscriber line to the wireless control device via the wireless base station, and The device causes the connected maintenance terminal to indicate that the subscriber line is faulty, and the radio control device sends a fault message of the subscriber line to the telephone exchange. And Shin, when the telephone exchange receives a fault message of the subscriber line,
A message indicating that there is a failure in the subscriber line is transmitted from the announcement device to the calling subscriber telephone that has made a call to the subscriber telephone connected to the subscriber line via the public telephone network.

[0014]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a wireless local loop system according to an embodiment of the present invention, and FIG.
3 is a block diagram illustrating a subscriber terminal according to the present embodiment, FIG. 3 is a block diagram illustrating a wireless base station according to the present embodiment, and FIG. 4 is a block diagram illustrating a wireless control device according to the present embodiment.

In FIG. 1, a wireless local loop system (WLL) according to the present embodiment includes a subscriber telephone (TEL) 5 for making a call and a subscriber line (SL) 6 connected to the TEL 5.
, And a call signal from the TEL 5 and a signal related to a call such as a dial are modulated into a digital radio signal and transmitted.
Terminal (SU) that demodulates to an analog signal to be sent to
4, a radio base station (BS) 3 connected to a plurality of subscriber terminals including the SU 4 via a radio line to transmit and receive digital radio signals, and a plurality of radio base stations (B) including the BS 3
S) and a wireless controller (BSC) 2 which is connected by a wired line (optical fiber cable or metallic cable) and performs call processing such as connection control to a plurality of SUs via a plurality of wireless base stations (BS). , BSC 2 and a local exchange (LS) connected to the public telephone network 9.

Also, a maintenance terminal (MAT) for displaying a message of a result of detection of a failure to each subscriber telephone under the control of the BSC 2 under the control of the BSC 2 is provided in the BSC 2.
The local exchange (LS) 1 further includes an announcement device (ANW) for transmitting a failure message received from the BSC 2 to the caller involved in the failure by voice under the control of the LS1. 8 are connected.

In FIG. 2, a subscriber terminal (SU) 4 in the present embodiment is such that a subscriber telephone (TEL) 5 is connected to a subscriber circuit 20 of the subscriber terminal (SU) 4. The subscriber circuit 42 supplies DC-48V to TEL5 and is ON.
/ Off-hook detection, transmission of ringing from the signal tone generation circuit 45, and transmission of a tone.
The voice signal transmitted from the TEL 5 is transmitted to the radio circuit 43 via the subscriber circuit 42, digitized and modulated by the voice signal, and transmitted to the BS 3 via the antenna 46 connected to the radio circuit 43. You. The digital wireless audio signal transmitted from the BS 3 is demodulated and decoded into an analog signal by the wireless circuit 43 and transmitted to the TEL 5 via the subscriber circuit 42. The failure detection circuit 44 detects a failure of the subscriber line 6 and notifies the CPU 41 of the failure of the subscriber line 6. The CPU 41 is configured by a microcomputer that operates according to a storage program method, and controls the subscriber circuit 42, the wireless circuit 43, the failure detection circuit 44, and the signal generation circuit 45.

In FIG. 3, a radio base station (BS) 3 according to the present embodiment receives a digital signal from a BSC 2 connected by a wired circuit in a bipolar state and converts it into a unipolar signal. B to convert digital signal of state to bipolar and transmit to BSC2
/ U38-1, 38-2 and the ATM signal from BSC2 as a digital signal and the digital signal from SU4 as AT
An ATM CLAD 36 for converting to an M signal, a digital switch 35 for performing an exchange connection for transmitting and receiving digital signals,
A distribution circuit 31 for receiving radio digital signals from a plurality of subscriber terminals via an antenna 39, transmitting a radio signal from the BS 3 via an antenna 39, and receiving a radio signal from the distribution circuit 31 Receive amplifier 3 to amplify
3, a transmission amplifier 32 for amplifying a radio signal to be sent to each of the plurality of subscriber terminals, a radio signal from the reception amplifier 33, and a radio signal from the BSC 2 for the transmission amplifier 32.
34 for transmitting to BS and C for controlling the whole inside BS3
PU37.

In FIG. 4, a radio controller (BSC) 2 according to the present embodiment transmits / receives a digital signal between LS1 and BSC2 in a bipolar state and a digital signal in BSC2 in a unipolar state. 1, B
/ U28-2 and the ATM signal between the BS3 and the BSC2 in the bipolar state and the unipolar state in the BSC2 in the A state.
B / U27-1, B / U27- for transmitting and receiving TM signals
, A digital switch 22 for performing exchange connection of digital signals, and an ATM switch 2 for performing exchange connection of ATM signals
1 and a Variable CODEC 23- which exchanges ATM signals and digital signals by exchanging signal speeds.
, 23-2, a memory 25 storing a program for controlling the program in the BCS 2 and storing a predetermined message in the event of a system failure; an ATM switch 21 via a control bus 26; Switch 22, Variable CODEC 23-1, 2-32
And a CPU 24 for controlling the Also, BSC2
Is a maintenance terminal (MA
T) 7 is connected to the control bus 26.

FIG. 5 is a sequence diagram showing a flow of operation at the time of receiving a call to the subscriber terminal according to the present embodiment.

Next, an operation of receiving a call to the subscriber's telephone and a method of detecting and reporting a failure in the subscriber line at that time according to the present embodiment will be described with reference to FIGS.

However, description of the internal operation of the BSC and BS3 is omitted.

In FIGS. 1 and 5, when the LS 1 detects an incoming call to the TEL 5 from the public telephone network 9, the LS 1 transmits an incoming call message (S0) including the subscriber number of the TEL 5 to the BSC 2 that controls the TEL 5. The BSC 2 stores the TEL 5 based on the received call message (S 0).
The BS3 transmits an incoming call message (S1) to the
, An incoming call message (S1) is transmitted to the SU 4 connected to the subscriber line (SL) 6 via a wireless transmission path.

When the SU4 receives the incoming message (S1), the SU4 sends the incoming response message (S2) via the BS3 to the BS.
Return to C2. The BSC 2 that has received the incoming call response message (S2) selects a communication channel on the wireless transmission path to be used for voice signal transmission from the available communication channels, and allocates the communication channel to the SU 3 via the BS 3 and the wireless transmission path. Assign a number to a wireless communication channel (S3)
And send it. The SU 4 having received the wireless communication channel assignment (S3) via the BS 3 transmits a wireless communication channel assignment response (S4) to the BS 3 via wireless transmission, and the BS 3 transmits the received wireless communication channel assignment response (S4) to the BSC 2. Send. The BSC 2 transmits a ringing transmission request (S5) to the SU4 via the BS3 and the wireless transmission path in order to ring the TEL5 connected to the SU4.

Next, an example of the operation of SU4 after receiving the ringing transmission request (S5) will be described with reference to FIGS.
This will be described with reference to FIG.

In FIG. 2, the ringing transmission request (S5) received by the radio circuit 43 via the radio transmission path is sent to the CPU.
Send to 41. The CPU 41 sends an instruction to the failure detection circuit 44 to confirm the normality of the subscriber line (SL) 6. The failure detection circuit 44 checks the normality of the subscriber line (SL) 6 via the subscriber circuit 42 (S6 in FIG. 5), and indicates whether the subscriber line 6 is normal or a failure has occurred. Is returned to the CPU 41. If a failure has occurred in the subscriber line 6, the CPU 41 transmits an instruction to the wireless circuit 43 to transmit a disconnection message (S7) storing the failure information of the subscriber line 6 to the BS 3 via the wireless transmission path. I do. Wireless circuit 43 that has received an instruction from CPU 41
Transmits a disconnection message (S7) storing failure information of the subscriber line 6 to the BS 3 via the wireless transmission path.

The failure detection circuit 44 is a subscriber circuit (SL) 6
As a method of detecting a failure, the failure detection circuit 44 includes a TEL from the subscriber circuit 44 via a subscriber line (SL).
5 or a predetermined normal impedance range from the 48 V DC power supply of the subscriber circuit 42 to TE.
A preset normal DC current range flowing in L5 is stored, and a ringing transmission request (S5) is stored.
Is received from the subscriber circuit 42 to the TEL 5, the result of the measurement of the impedance or the DC current value from the subscriber circuit 42 to the TEL 5 is compared with the respective normal ranges shown above. The normality of the user line 6 is determined.

Next, an example of the operation after the radio circuit 43 of the SU 4 transmits a disconnection message (S7) storing the failure information of the subscriber line 6 to the BS 3 via the radio transmission path will be described with reference to FIGS.
This will be described with reference to FIG.

BS3, which has received the disconnection message (S7) storing the failure information of the subscriber line 6 from the SU4 via the radio transmission path, transmits it to the BSC2. BSC2 is BS
C2 reads the failure information of the subscriber line 6 stored in the disconnection message (S7) received from the BS 3, and recognizes that the subscriber line 6 has a failure. BSC2 transmits a disconnection response message (S8) to BS3 as a response to the disconnection message (S7), and BS3 transmits it to SU4 via a wireless transmission path. Due to the transmission and reception of the disconnection message (S7) and the disconnection response message (S8), the incoming call processing is canceled halfway.

After transmitting the disconnection response message S8 to release the incoming call processing, the BSC 2 notifies the LS 1 and the maintenance terminal 6 of the failure of the subscriber line 6 (S9 in FIG. 5). The maintenance terminal 6 receiving the failure of the subscriber line 6 displays on the display device incorporated in the maintenance terminal 6 that the failure has occurred in the subscriber line 6, and notifies the maintenance person of the failure of the subscriber line 6. I do.
(S10 in FIG. 5) When the LS1 receives the failure of the subscriber line 6, it activates the announcement device (ANW) 8 and sends a voice message corresponding to the failure of the subscriber line via the public telephone network 9 to the caller. Notify to

Another service system on the LS1 side is that when the failure of the subscriber line 6 is recovered, the telephone numbers of a plurality of subscriber telephones that have made calls to the TEL 5 at the time of the failure are stored at the time of the incoming call. Is restored, a call can be made to all the subscriber telephones that made a call to TEL5 at the time of the failure, and a message indicating that the failure of the subscriber line from ANW8 to TEL5 has been recovered can be transmitted.

[0033]

As described above, according to the present invention, each subscriber terminal is connected to a subscriber telephone set via a subscriber line, and each subscriber terminal is connected to a radio base station via a radio line. The wireless base station connects to a wireless control device via a first wired line, and the wireless control device connects to a telephone exchange connected to a public telephone network via a second wired line. In the loop system, each subscriber terminal has a line failure detecting means for detecting a failure of a subscriber line to a subscriber telephone to which the subscriber terminal is connected, and the radio controller receives an incoming message from the telephone exchange and After transmitting the incoming call message via the base station to the subscriber terminal connected to the subscriber telephone number corresponding to the subscriber number stored in the incoming call message, there is no failure in the subscriber line to which the subscriber terminal is connected. By providing a notifying means for notifying the maintenance person that the subscriber line has failed when received via the base station, the subscriber terminal is connected to the subscriber line every time an incoming call message is received. When a failure is detected by checking the normality, the maintenance person is notified online and the failure is reduced. There is an effect that can be done.

Further, in the event of a failure of the subscriber line, a message regarding the failure of the subscriber line is notified from the announcement device to the caller in a response waiting state, so that the anxiety of the caller can be eliminated. There is.

Further, since a message at the time of a failure of the subscriber line from the subscriber terminal can be inserted into a normal process at the time of an incoming call, a special message for the failure can be defined and maintained without occurrence. Has the effect of notifying the user.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a wireless local loop system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a subscriber terminal according to the present embodiment shown in FIG.

FIG. 3 is a block diagram illustrating a wireless base station according to the present embodiment.

FIG. 4 is a block diagram illustrating a wireless control device according to the present embodiment.

FIG. 5 is a sequence diagram showing an example of an operation flow at the time of receiving a call to a subscriber terminal according to the present embodiment.

FIG. 6 is a schematic diagram showing an example of a conventional WLL system.

FIG. 7 shows a first example of the conventional WLL system shown in FIG.
FIG. 2 is a diagram illustrating a test system of FIG.

FIG. 8 shows a second example of the conventional WLL system shown in FIG.
FIG. 2 is a diagram illustrating a test system of FIG.

[Explanation of symbols]

 1 Local exchange (LS) 2 Radio control unit (BSC) 3 Radio base station (BS) 4 Subscriber terminal (SU) 5 Subscriber telephone (TEL) 6 Subscriber line (SL) 7 Maintenance terminal (MAT) 8 Announcement Device (ANW) 9 Public telephone network 21 ATM switch 22 Digital switch 23-1, 23-2 Variable CODEC 24 CPU 25 Memory 26 Control bus 27-1, 27-2, 28-1, 28-2 B / U 31 Distribution Circuit 32 Transmission amplifier 33 Receiving amplifier 34 Transceiver 35 Digital switch 36 ATM CLAD 37 CPU 38-1, 38-2 B / U 41 CPU 42 Subscriber circuit 43 Radio circuit 44 Failure detection circuit 45 Signal tone generation circuit 46 Antenna

Claims (7)

(57) [Claims] 1. Each subscriber terminal is connected to a subscriber telephone set via a subscriber line, and each subscriber terminal is connected to a radio base station via a radio line, and the radio base station is connected to a radio base station. A wireless local loop system connected to a wireless switching device connected to a public telephone network via a second wired line, wherein the wireless local loop system is connected to the wireless control device via one wired line; The subscriber terminal includes a line failure detecting means for detecting a failure in a subscriber line between the subscriber terminal and the subscriber telephone to which the subscriber terminal is connected, and the radio control device receives an incoming call message from the telephone exchange to receive the incoming call. Subscription to which the subscriber terminal is connected after transmitting the incoming call message via the radio base station to a subscriber terminal connected to the subscriber telephone corresponding to the subscriber number stored in the call message When a failure in the line is received through the radio base station, a wireless local loop system, characterized in that it comprises a notification means for notifying that said subscriber line becomes impaired to maintenance personnel. 2. The radio control apparatus notifies the telephone exchange of fault information of the subscriber line and also transmits the fault information of the subscriber line to a maintenance terminal connected to the radio control apparatus as the reporting means. 2. The wireless local loop system according to claim 1, wherein said maintenance terminal has display means for displaying failure information of said subscriber line. 3. The telephone exchange device, upon receiving fault information of the subscriber line from the preceding radio control device, connects the public telephone network to a calling subscriber telephone which has made a call to a subscriber telephone connected to the subscriber line. 3. The wireless local loop system according to claim 1, further comprising: an announcement device for transmitting a message indicating that the subscriber line is faulty via the network. 4. The subscriber terminal is connected to the subscriber telephone via the subscriber line and a DC is connected to the subscriber telephone.
-48 V power supply, ON / OFF-hook detection, ringing from signal sound generation circuit and transmission of various tones, subscriber circuit, signal sound generation circuit for generating the ringing and various tones, and antenna A radio circuit for receiving and demodulating a digital radio signal from the radio base station into an analog signal, modulating an analog signal from the subscriber circuit into a digital radio signal, and transmitting the signal. A failure detection circuit that detects a failure in the subscriber circuit via the subscriber circuit; and, upon receiving a detection signal of failure detection of the subscriber line from the failure detection circuit, transmits the subscriber line information to the wireless circuit. And a CPU for transmitting the subscriber circuit, the radio circuit, the signal tone generating circuit, and the fault detecting circuit. Wireless local loop system according. 5. Each subscriber terminal is connected to a subscriber telephone set via a subscriber line, and each subscriber terminal is connected to a radio base station via a radio line. A wireless local loop system connected to a telephone exchange connected to a public telephone network via a second wired line, wherein the wireless local loop system is connected to the wireless controller via a first wired line; When the control device receives an incoming call message from the telephone exchange, the control device transmits the incoming call message to a subscriber terminal connected to a subscriber telephone set corresponding to the subscriber number stored in the incoming call message via the radio base station, The subscriber terminal that has received the incoming call message tests the presence or absence of a failure in the connected subscriber line by the line failure detection means. Of a fault message is transmitted to the radio network controller, the radio controller failure detection and reporting method of a wireless local loop system, characterized in that the notification to the maintenance person a failure of the subscriber line via a notification means. 6. Each subscriber terminal is connected to a subscriber telephone set via a subscriber line, and each subscriber terminal is connected to a radio base station via a radio line. A wireless local loop system connected to a telephone exchange connected to a public telephone network via a second wired line, wherein the wireless local loop system is connected to the wireless controller via a first wired line; When the control device receives the incoming call message from the telephone exchange, the control device transmits the incoming call message to the subscriber terminal connected to the subscriber telephone number corresponding to the subscriber number stored in the incoming call message via the radio base station, The subscriber terminal having received the incoming call message returns an incoming call response message via the radio base station, and the radio control apparatus having received the incoming call response message returns Sending a wireless communication channel assignment to the subscriber terminal via a base station, and then the subscriber terminal responds to the radio controller that the radio communication channel assignment has been received, and When the apparatus makes a ringing transmission request for the subscriber telephone set to the subscriber terminal, the subscriber terminal that has received the ringing transmission request determines whether there is a failure in the subscriber line connected by the line failure detection means. And when a failure is detected, a failure message of the subscriber line is transmitted to the wireless controller via the wireless base station, and the wireless controller transmits a failure of the subscriber line to a connected maintenance terminal. A method for detecting and reporting a failure in a wireless local loop system. 7. The radio control unit transmits a failure message of the subscriber line to the telephone exchange, and the telephone exchange, upon receiving the failure message of the subscriber line, connects the subscriber telephone to the subscriber line. 7. The wireless local loop according to claim 5, further comprising transmitting a message indicating a failure of the subscriber line from the announcement device to the calling subscriber's telephone set via the public telephone network. System failure detection / reporting method.