JP2912253B2 - Antenna failure detection circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna failure detection circuit of a radio base station apparatus provided with an electric field monitoring receiver of an adjacent radio base station apparatus.

[0002]

2. Description of the Related Art FIG. 4 shows a configuration of a conventional mobile communication system, in particular, a radio base station apparatus used in the Japanese digital system.
Shown in This apparatus receives a transmission / reception antenna 2, a reception-only antenna 3, and a communication channel designation signal, and receives a signal at a predetermined frequency corresponding to the channel designation signal.
Via the transmitting / receiving antenna 2 and the receiving-only antenna 3,
It comprises a call transceiver 6 for intercommunicating with the mobile terminal 9 and a downstream electric field monitoring receiver 7 for monitoring the downstream radio wave state of the adjacent radio base station device 8 via the reception-only antenna 2. ing. One example is disclosed in
There is a mobile radio communication system disclosed in Japanese Patent No. 268697.

[0005] An example of a zone configuration of a wireless base station system using the wireless base station device 1 is as shown in FIG. For example, a case where the adjacent wireless base station device 8 in the adjacent wireless zone is communicating with the mobile terminal 16 (the line frequency at this time uses f2) will be described. First, the downlink electric field monitoring receiver 7 of the radio base station apparatus 1 is activated, the electric field value of the downlink radio wave (f2) of the adjacent radio base station apparatus 8 is detected, and the electric field value of the frequency and the radio wave generation rate are determined. Measure. In consideration of this result, the line frequency of the call transceiver 6 of the radio base station apparatus 1 is dynamically determined, and the line frequency (f2) of the mobile terminal 16 and a frequency of not less than Δf that does not receive radio interference. The wireless section communication is performed using the line frequency (f1) from which.

[0004] As a method of detecting an antenna failure of the wireless base station apparatus 1 having such a downlink electric field monitoring receiver 7,
On the transmission / reception antenna 2 side, using the transmission radio wave of the call transmission / reception transceiver 6, the signal is received by the downlink electric field monitoring receiver 7 via the reception-only antenna 3 using spatial propagation, and the magnitude of the input electric field value is increased. (Hereinafter, referred to as RSSI), it can be easily estimated that the antenna failure can be determined.

On the other hand, the reception-only antenna 3 can use external equipment such as a test transmitter to determine the presence or absence of reception and determine the antenna failure.

One example of this is a car telephone disclosed in Japanese Patent Application Laid-Open No. 63-269628.

[0007]

As a method for detecting an antenna failure in the above-mentioned conventional radio base station apparatus, the transmitting and receiving antenna side uses a radio wave transmitted from a telephone transceiver to receive data by utilizing inter-antenna space propagation. Via a dedicated antenna,
Antenna failure can be determined based on the magnitude of the input electric field value (hereinafter, referred to as RSSI) received by the downlink electric field monitoring receiver.

On the other hand, the reception-only antenna side can receive using an external facility such as a test transmitter, and determine the antenna failure based on the RSSI value.

[0009] Therefore, since the failure detecting means for each antenna is provided independently, there is a drawback that the wireless base station apparatus is prevented from being reduced in size and cost.

[0010] It is an object of the present invention to provide an antenna failure detection circuit which can independently detect a failure in a transmitting / receiving antenna and a receiving-only antenna with one detection function.

According to the present invention, in a radio base station apparatus, a communication channel designation signal is input, and an uplink / downlink radio wave of a predetermined frequency corresponding to the communication channel designation signal passes through a transmission / reception antenna and a reception only antenna. A communication transceiver for intercommunicating with the mobile terminal, and a downlink electric field monitoring receiver that receives an electric field monitoring channel designation signal and monitors the state of a downlink radio wave of a predetermined frequency corresponding to the electric field monitoring channel designation signal. In the antenna failure detection circuit provided, it is connected in series between the transceiver for communication and the transmission / reception antenna, and inputs the down-stream radio wave of the transceiver for communication to the first terminal and passes through the second terminal with low loss. To the transmitting and receiving antennas, and the downlink radio waves from the transmitting and receiving antennas
A circulator that inputs to the terminal of the circulator and outputs a low loss from the third terminal; a downstream radio wave that passes through the circulator is input to the first input terminal; And an antenna changeover switch that conducts and outputs any one of the input terminals according to a changeover signal, and detects a failure of the reception-only antenna.
In the case of the confirmation operation, set the antenna changeover switch to the second input terminal.
Switch to a receive-only antenna by conducting with the
When the antenna is normal, the antenna selector switch is
Of the electric field monitoring receiver conducted to the antenna for
The value increases, and in the event of an abnormality, the receive-only antenna is totally reflected
Mode and the power value of the downlink electric field monitoring receiver is low.
Antenna, check the failure of the transmitting and receiving antennas.
Switch is connected to the first input terminal to transmit and receive
When the transmitting and receiving antennas are normal,
The power value of the monitoring receiver decreases, and the
Always check that the electric power value of the
Using the door, an antenna failure detection circuit which is characterized in that the transmission and reception antenna and the reception antenna failure detection autonomously.

It is preferable that failure detection of a transmitting / receiving antenna and a receiving antenna is performed based on an input electric field value corresponding to input power.

Further, it is preferable that a value to be detected at the time of a failure is preset as an input electric field value, and that a failure is determined when an actually measured input electric field value is close to a value to be detected at the time of a failure.

As a criterion for this determination, a failure can be determined when the actually measured input electric field value is ± 1 V with respect to a preset value.

[0015]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of an antenna failure detection circuit according to the present invention. The radio base station device 1 includes a transmitting / receiving antenna 2 and a receiving-only antenna 3,
A call transceiver 6 for intercommunicating with a mobile terminal 9 having a diversity function through an up / down radio wave of a predetermined frequency corresponding to a call channel designation signal via a transmission / reception antenna 2 and a reception antenna 3; It is connected in series between the call transceiver 6 and the transceiver antenna 2,
The downstream radio wave of the call transceiver 6 is input to the first terminal 11 and supplied to the transmitting / receiving antenna 2 via the second terminal 12 with low loss, and the transmitting / receiving antenna 2 transmits the radio wave of the adjacent radio base station apparatus 8 to the transmitting / receiving antenna 2. A circulator 4 which inputs a 0-system downstream radio wave to its second terminal 12 and outputs it from the third terminal 13 with low loss, and a 0-system downstream radio wave of an adjacent wireless base station device 8 passing through the circulator 4 Is input to the first input terminal 14, and the downstream radio wave of the first system of the adjacent radio base station apparatus 8 input from the reception-only antenna 3 is input to the second input terminal 15, and any one of the An antenna changeover switch that conducts and outputs a terminal, and an antenna changeover switch having a predetermined frequency corresponding to an electric field monitoring channel designation signal.
It comprises a downstream electric field monitoring receiver 7 for monitoring the downstream radio wave state of the adjacent base station device 8 via the.

FIGS. 2A and 2B are diagrams for explaining the operation of the antenna failure detection circuit according to the present invention. FIG. 2A is for a reception-only antenna (the antenna switch is electrically connected to the second input terminal side), and FIG. ) Is for a transmitting / receiving antenna (the antenna switch is electrically connected to the first input terminal).

First, as an operation for detecting the failure of the reception-only antenna 3, the communication transceiver 6 is set to a predetermined frequency f1 by a communication channel designation signal, and a constant power (10 dB) is set.
m) is emitted. At the same time, the antenna changeover switch 5 is electrically connected to the second input terminal 15 by the changeover signal, and switches to the reception-only antenna 3 side. Next, the downlink electric field monitoring receiver 7 sets the local oscillation unit to f2 (f2) so that f1 can be received by the electric field monitoring channel designation signal.
= F1 + 1f) is set. That is, the downlink radio frequency of the telephone transceiver 6 and the downlink radio frequency of the downlink electric field monitoring receiver 7 match. Therefore, a loop of radio waves is established through spatial propagation loss by the communication transceiver 6, the circulator 4, the transmission / reception antenna 2, the reception-only antenna 3, the antenna changeover switch 5, and the downlink electric field monitoring receiver 7.

For example, as shown in the mode A of FIG. 2A, when the reception-only antenna 3 is in a normal state where there is no failure, the antenna changeover switch 5 is conducted to the reception-only antenna 3 by a switching signal. First, when a constant electric power (10 dBm = fixed value) is output from the transmitting / receiving antenna 2 to the downlink radio wave of the telephone transceiver 6, the gain of the receiving antenna 3 and the physical distance between the antennas are fixed in advance. Therefore, the spatial propagation loss between the antennas having an approximate value (−40 dB = fixed value) and the antenna changeover switch 5
Only the transmission line with an insertion loss of (-1 dB) is attenuated, and the receiver 7 for monitoring the downstream electric field (10 dBm-40 dB-1d)
B) An electric field value of −39 dBm is input, and RS corresponding to the electric field value of the downlink electric field monitoring receiver 7 as shown in FIG.
The SI value (3.0 V) is detected. As a result, since the receiving antenna 3 is extremely higher than the RSSI value (1.2 V) to be detected at the time of failure, the receiving-only antenna 3 is determined to be normal.

When an abnormality such as breakage of the receiving antenna 3 occurs as shown in mode B of FIG. 2A, the VSWR at the input terminal of the receiving antenna 3 of the radio base station apparatus 1 is infinite. The down radio wave of the call transceiver 6 is output at a constant power (10 dBm) from the transmission / reception antenna 2 due to great care, but the reception antenna 3 is in the total reflection mode, and the reception antenna 3 A predetermined input power is not supplied, and a power value (−69 dBm) about 30 dB lower than the normal state by the total reflection amount of the antenna is obtained.
It is input to the downstream electric field monitoring receiver 7 and detects an RSSI value (1.0 V) corresponding to the input power value. As a result, when the reception-only antenna 3 is
It is determined that it is almost equal to the SI value (1.2 V), and the reception-only antenna 3 is determined to be abnormal. Since the RSSI value detected at the time of failure is affected by how the reception-only antenna 3 is bent or a natural environment such as rain, it is necessary to set the RSSI value to about 1.2V ± 1V.

On the other hand, as an operation for confirming the failure detection of the transmitting / receiving antenna 2, the antenna switching SW5 is conducted to the first input terminal 14 by the switching signal, and is switched to the transmitting / receiving antenna 2 side. In other words, switching to the circulator 4 side,
A radio wave loop is established by the call transceiver 6, the circulator 4, the antenna changeover switch 5, and the receiver 7 for monitoring a down electric field.

For example, as shown in a mode C of FIG. 2B, when the transmitting / receiving antenna 2 outputs a down radio wave (−20 dBm) of the communication transmitter / receiver 6 in a normal state where there is no failure, the transmitting / receiving antenna 2 , The reflected power is small, the coupling amount with the circulator 4 is low (−20 dB), only the transmission path is attenuated via the insertion loss (−1 dB) of the antenna changeover switch 5, and (−20 dBm−20 dB-1)
dB) = − 41 dBm is input, and the RSSI value (2.8) is input.
V) is detected. As a result, since the transmitting / receiving antenna 2 is extremely lower than the RSSI value (4.5 V) detected at the time of failure, the transmitting / receiving antenna 2 is determined to be normal.

As shown in mode D of FIG. 2B, when an abnormality such as a break of the transmitting / receiving antenna 2 occurs, the VSWR at the input end of the transmitting / receiving antenna 2 of the radio base station apparatus 1 is infinite. As a result, the downstream radio wave (−20 dBm) of the communication transceiver 6 is not supplied to the transmission / reception antenna 2 but enters the total reflection mode, and the coupling amount of the circulator 4 decreases (−1 dB). Therefore, a power value that is about 20 dB higher than the normal state is transmitted to the downlink electric field monitoring receiver 7 by (−20 dBm−1 dB−1 dB) =
-22 dBm is input, and the RSSI value (4.5 V) is detected. As a result, it is determined in advance that the transmitting / receiving antenna 2 is equal to the RSSI value (4.5 V) detected at the time of failure, and the transmitting / receiving antenna 2 is determined to be abnormal.

FIG. 3 is a graph showing the input power and the RSSI characteristic of the receiver for monitoring a down electric field of the present invention. An abnormality occurs near the transmission / reception antenna failure level set value of 4.5 V indicated by the dotted line in the figure and near the reception-only antenna failure level set value of 1.2 V also indicated by the dotted line.

[0025]

As described above, according to the present invention, the failure detection of the transmission / reception antenna and the reception-only antenna can be determined only by the reception failure for monitoring the down electric field using the transmission radio wave of the communication transceiver. There is an advantage that it can contribute to miniaturization and cost reduction of the base station device.

Further, according to the present invention, the receiver for monitoring a down electric field can have an antenna switching diversity function,
There is an advantage that it can also contribute to improvement in the reliability of the receiver for monitoring the downlink electric field of the wireless base station device.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the structure of a wireless base station device provided with an antenna failure detection circuit according to the present invention.

FIGS. 2A and 2B are diagrams for explaining the operation of the antenna failure circuit of the present invention, wherein FIG. 2A is for a reception-only antenna and FIG.

FIG. 3 shows the input power and R of the downlink electric field monitoring receiver of the present invention.
5 is a graph showing SSI characteristics.

FIG. 4 is a block diagram showing the structure of a conventional radio base station device.

FIG. 5 is a diagram showing a configuration of a wireless communication zone.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Radio base station apparatus 2 Transmission / reception antenna 3 Reception only antenna 4 Circulator 5 Antenna switch 6 Communication transceiver 7 Downstream electric field monitoring receiver 8 Adjacent radio base station apparatus 9 Mobile terminal 10 Line zone 11 First terminal 12 First 2 terminal 13 3rd terminal 14 1st input terminal 15 2nd input terminal 16 Mobile terminal

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04B 7/24-7/26 H04B 17/00-17/02 H04Q 7/00-7/38

Claims (4)

(57) [Claims] A radio base station apparatus receives a communication channel designation signal as input, and transmits and receives a predetermined frequency corresponding to the communication channel designation signal via an uplink / downlink radio wave via a transmission / reception antenna and a reception-only antenna. A communication transceiver for intercommunicating with the mobile terminal, and a downlink electric field monitoring receiver that receives an electric field monitoring channel designation signal as input and monitors the state of a downlink radio wave of a predetermined frequency corresponding to the electric field monitoring channel designation signal. An antenna failure detection circuit comprising: a second terminal connected in series between the transceiver for communication and the transmission / reception antenna to receive a radio wave transmitted from the transceiver for transmission to a first terminal and to have a low loss at a second terminal; To the transmission / reception antenna via the transmission / reception antenna, and input a down radio wave from the transmission / reception antenna to the second terminal and output from the third terminal with low loss. A circulator, and a downstream radio wave passing through the circulator is input to a first input terminal, and a downstream radio wave input from the reception-only antenna is input to a second input terminal. Further comprising an antenna changeover switch for conducting and outputting the signal , in the case of a failure detection confirmation operation of the reception-only antenna,
Making the antenna change-over switch conductive with the second input terminal;
Switch to the reception only antenna side, and
When the antenna is normal, the antenna selector switch
To the antenna for exclusive use to monitor the downlink electric field.
If the power value of the equipment becomes high and the
The tena is in the total reflection mode, and the
In the case where the power value becomes low and the transmission / reception antenna malfunctions, the antenna
The switch is turned on with the first input terminal to
Switch to the transmitting and receiving antenna side, the transmitting and receiving antenna is normal
Sometimes, the power value of the downlink electric field monitoring receiver is low.
When the transmitting / receiving antenna is abnormal, the
By utilizing the fact that the power value of the visual receiver increases, the transmission <br/> receiving antenna and the antenna failure detection circuit and performs autonomously failure detection of the reception antenna. 2. The antenna failure detection circuit according to claim 1, wherein failure detection of said transmission / reception antenna and reception-only antenna is performed based on an input electric field value corresponding to said input power. 3. A method in which a value to be detected at the time of a failure is preset as the input electric field value, and a failure is determined when the actually measured input electric field value is close to the value to be detected at the time of the failure. The antenna failure detection circuit according to claim 2, wherein: 4. The antenna failure detection according to claim 2, wherein a failure is determined when the actually measured input electric field value is ± 1 V with respect to the preset value. circuit.