JP2003087166A - Antenna switching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable transmission and reception by switching antennas when radio communication equipment is outside a communication area and when the antenna fails. SOLUTION: A first antenna 101 for both transmission and reception, a second antenna 102 for both transmission and reception and an antenna switch 105 for switching the antennas 101 and 102 are included, and a control unit 110 controls the antenna switch 105 to perform switching and selection of the antennas 101 and 102 for both transmission and reception. In the case the radio communication equipment becomes outside the communication area where receiving electric field intensity in a transmitting and receiving part 106 is not higher than prescribed and the outside-area information is inputted to the control unit 110 as the receiving level information 112, an output Q of a JK flip-flop 109 being an antenna switch signal 114 is inverted at the fall timing of a clock signal CLK of a CPU 108, and the antennas 101 and 102 for both transmission and reception are switched from one to the other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna switching device for wireless communication, and more particularly to an antenna switching device for use in a communication system for emergency calls, which is constructed by using a mobile phone, a mobile wireless device, and other wireless communication devices. Regarding

[0002]

2. Description of the Related Art In a radio communication device such as a mobile phone, so-called antenna diversity may be used in order to secure a stable reception state. A wireless communication device that utilizes antenna diversity usually includes a main antenna for both transmission and reception and a sub-antenna for reception only.By comparing the electric field strengths received by each antenna and switching the antennas, reception quality, that is, on the mobile unit side A configuration is adopted that improves the downlink connection quality of.

FIG. 5 is a block diagram showing a configuration example of a wireless communication device in a conventional emergency call communication system. The wireless communication device 500 includes a transmission / reception unit 501 that uses a wireless communication device such as a mobile phone as a module. The transmission / reception unit 501 uses a coaxial cable 502, 503 for a transmission / reception antenna 504 that is a main antenna and a reception-only antenna that is a sub antenna. It is connected to the antenna 505.
Further, a control unit 508, which has a built-in CPU 507 and controls various parts such as antenna switching, is provided, and the control unit 508 and the transmitting / receiving part 501 are connected by a control line 506.

The transmission / reception unit 501 is configured to perform diversity reception for switching between the transmission / reception antenna 504 and the reception dedicated antenna 505 according to the reception electric field strength. With such a configuration, it is possible to improve reception quality and perform stable reception.

Further, as a wireless communication apparatus for performing diversity reception, Japanese Patent Laid-Open No. 11-191750 has two sub-antennas, and one of the two sub-antennas having a higher reception level in an idle period of a reception frame is used. It is disclosed that a diversity effect can be reliably obtained by preselecting a switching sub-antenna and performing diversity reception with the main antenna and the selected switching sub-antenna. In addition, JP-A-1
Japanese Laid-Open Patent Publication No. 1-27190 includes an internal antenna and two external antennas. The internal antenna and the first external antenna are switched and selected according to the connection state of the external device, and the selected antenna and the second external antenna are selected. It has been disclosed that a good reception sensitivity is automatically obtained by automatically selecting one of the external antennas having a larger received electric field strength.

[0006]

However, in the antenna configuration in the conventional wireless communication apparatus such as the conventional example of FIG. 5 and Japanese Patent Application Laid-Open No. 11-191750 and Japanese Patent Application Laid-Open No. 11-27190, for emergency call, When used in a communication system, there is a problem that when the main antenna for both transmission and reception fails, transmission is not possible and the upstream signal from the mobile device does not reach the base station, which makes communication such as emergency notification impossible.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an antenna switching device capable of switching between antennas and transmitting and receiving when outside the communication range or when an antenna fails.

[0008]

According to the present invention, there is provided a first transmitting / receiving antenna and a second transmitting / receiving antenna, and an antenna switching means for selectively connecting and connecting the first and second transmitting / receiving antennas. And a transmitting / receiving unit that performs wireless communication using the first and second antennas for both transmission and reception,
On the basis of the reception level information in the transmitting / receiving means, when the reception electric field strength is equal to or lower than a predetermined value, the antenna switching signal input to the antenna switching means is inverted at a predetermined timing to reverse the first antenna switching signal. It is characterized by further comprising a switching control means for switching the transmission / reception antenna and the second transmission / reception antenna from one to the other.

Further, the switching control means may invert the antenna switching signal at a timing of a clock signal output at a predetermined time when the out-of-range information indicating the out-of-range communication state is output from the transmitting / receiving means. Characterize.

Further, the switching control means, when the reception electric field strength is equal to or more than a predetermined value, is in the communication area state, the first or second transmission / reception selected at that time without changing the antenna switching signal. Hold the dual-purpose antenna connection,
When in the out-of-communication state, the connection between the first transmission / reception dual-use antenna and the second transmission / reception dual-use antenna is switched according to the timing of a clock signal output at a predetermined time.

Further, the present invention further comprises a reception-only antenna, and the transmission / reception means performs diversity reception by the first or second transmission / reception antenna selected at that time and the reception-only antenna. Characterize.

Further, the switching control means is characterized in that the output timing of the clock signal can be changed depending on the reception state.

In the switching control means, the first transmission / reception antenna and the second transmission / reception antenna may be arranged at arbitrary timing.
It is characterized in that it can be set so that any one of the transmitting and receiving antennas of is selected as the initial state.

Further, the switching control means can be set to select either the first transmitting / receiving antenna or the second transmitting / receiving antenna as an initial state when the communication area state continues for a predetermined time. It is characterized by having done.

The switching control means according to the present invention is, for example, C
A control processor such as a PU and a logic circuit such as a JK flip-flop are provided to perform antenna switching control according to the reception state.

According to the present invention, when the reception electric field strength is equal to or less than the predetermined value, the communication state is changed by switching the first transmission / reception antenna and the second transmission / reception antenna from one to the other. Accordingly, the antenna for both transmission and reception is automatically switched, and even if one of the antennas fails, switching to the other antenna enables transmission and reception, and communication such as emergency notification can be secured.

Further, in the case where the reception-only antenna is provided, the reception quality can be improved by the diversity reception by performing the diversity reception by the one reception / transmission antenna and the reception-only antenna selected at that time in the communication area. Even if one antenna fails, the other antenna can perform communication such as an emergency report.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The present embodiment exemplifies the configuration of the antenna switching device in the wireless communication device used for the emergency call communication system and the like.

[First Embodiment] FIG. 1 is a block diagram showing the arrangement of an antenna switching apparatus according to the first embodiment of the present invention.
2 is an operation explanatory view showing an antenna switching sequence by the control unit, and FIG. 3 is an operation explanatory view showing the operation of the JK flip-flop provided in the control unit by a truth table.

The first embodiment comprises a first transmitting / receiving antenna 101 and a second transmitting / receiving antenna 102,
The wireless communication device 100 is configured to switch. The first transmitting / receiving antenna 101 is a coaxial cable 1
03, the second transmission / reception antenna 102 uses the coaxial cable 104 to change terminals 121 and 122 of the antenna changeover switch 105 in the wireless communication apparatus 100, respectively.
It is connected to the. The wireless communication device 100 includes a transceiver 1 that uses a wireless communication device such as a mobile phone as a module.
06, and the antenna connection terminal 1 of the transmission / reception unit 106.
25 is connected to the common terminal 123 of the antenna changeover switch 105 by the coaxial cable 107.

The wireless communication device 100 also includes a CPU 108, which is a control processor, and a JK flip-flop (J
K-FF) 109 is incorporated and a control unit 110 for controlling each part such as antenna switching is provided. The control unit 110 uses the serial control line 111 to transmit / receive the signal to / from the transmitting / receiving unit 1.
The reception level information 112 indicating the reception state is connected to the CPU 108 by the transmission / reception unit 106. The reception level information 112 includes out-of-range information indicating that it is out of the communication range. The control unit 110 also includes an antenna switching control line 113.
Control input terminal 12 of antenna changeover switch 105
4 and the output Q of the JK flip-flop 109 is used as the antenna changeover signal 114 and the antenna changeover switch 1
It is designed to be input to 05. Further, the wireless communication device 100 is provided with a display unit 115 that displays a communication state such as an out-of-service area display when out of the communication area, and an operation unit 116 that inputs operation such as operation settings.

The operation of the antenna switching device of this embodiment constructed in such a wireless communication device will be described. If the wireless communication device 100 moves out of the service area of the base station or if the antenna fails, the transmitting / receiving unit 106
In the case where the received signal strength is less than a predetermined value and the communication area is out of the communication area, a serial signal representing the out-of-area information is received as the reception level information 112 via the serial control line 111.
It is transmitted to U108. The CPU 108, based on the serial signal representing the out-of-range information and the clock signal CLK generated in the CPU 108, the JK flip-flop 10
The operation of the JK flip-flop 109 is controlled by inputting a binary control signal to each of the inputs J, K and CK of 9. Then, the antenna changeover signal 114 from the output Q of the JK flip-flop 109 is used to control the antenna changeover switch 105 to switch between the first transmitting / receiving antenna 101 and the second transmitting / receiving antenna 102.

FIG. 2 shows an antenna switching sequence in the present embodiment. Here, for ease of explanation, a serial signal representing out-of-range information is at a high level (hereinafter referred to as "H") when out of communication range. It is indicated by a binary out-of-service signal OS.

In FIG. 2, t1 and t5 are out-of-service signals OS.
Rise, t3, and t7 indicate respective fall timings of the out-of-service signal OS. Also, t2, t4, t6, t8
Indicates the falling timing of the clock signal CLK. The output Q of the JK flip-flop 109, which is the antenna switching signal 114, is controlled by the logic of the out-of-range signal OS and the clock signal CLK. Here, the logic control is performed such that the output Q is inverted at the falling timing when the out-of-service signal OS is "H" and the clock signal CLK changes from "H" to a low level (hereinafter referred to as "L"). .

FIG. 3 is a truth table showing the logical operation of the JK flip-flop 109 for realizing the antenna switching sequence of FIG. As shown in Figure 3, J
The K flip-flop 109 receives inputs J and K when both the inverted CLR− of the clear input CLR (hereinafter, − after the sign of the signal indicates inversion) and the inverted PR− of the preset input PR are “H”. And the output Q changes according to the clock input CK. In the output Q and the inverted output Q- in FIG. 3,
Qn represents maintaining the previous state, and Qn- represents inversion from the previous state.

When the electric field intensity received by the transmitting / receiving unit 106 is equal to or larger than a predetermined value and the communication area is within the communication range, the CPU 108 is
The input J = “L” and the input K = “L” are input as the control signals corresponding to the “L” of the out-of-service signal OS. Further, when the reception electric field strength in the transmission / reception unit 106 is out of the communication range with a predetermined value or less, the input J = “H” and the input K = “H” are used as the control signals corresponding to the “H” of the out-of-service signal OS in FIG. Enter ".

As a result, during communication, the falling edge of the inverted CK- of the clock input, that is, the clock signal C
Even when LK falls, the output Q does not change and maintains the previous state. Note that the output Q is unchanged regardless of the states of the inputs J and K at the rising edge of the inverted CK− of the clock input, that is, the rising edge of the clock signal CLK. In this case, since the antenna switching signal 114 does not change, of the first transmitting / receiving antenna 101 and the second transmitting / receiving antenna 102, the antenna connected at that time is retained as it is as the used antenna.

On the other hand, outside the communication range, the output Q is inverted from the state immediately before at the fall of the inverted CK- of the clock input, that is, the fall of the clock signal CLK.
In this case, since the antenna switching signal 114 is inverted, one of the first transmitting / receiving antenna 101 and the second transmitting / receiving antenna 102, which is connected at that time, is switched to the other antenna.

Here, the antenna changeover switch 105
Indicates that the output Q input to the control input terminal 124 is "L",
That is, when the antenna switching signal 114 is “L”, the first transmitting / receiving antenna 10 is connected to the switching terminal 121 side.
When 1 is selected and the output Q is "H", that is, the antenna switching signal 114 is "H", the switching terminal 122 is connected to operate to select the second transmitting / receiving antenna 102. In the initial state and normal state when the power is turned on, the first transmitting / receiving antenna 101 is preset to be selected.

The timing cycle of rising and falling of the clock signal CLK that determines the switching timing of the antenna is from when the antenna is switched by the antenna changeover switch 105 until when the transmitting / receiving unit 106 changes from the out-of-communication state to the in-communication state. It should be set longer than the time. As a result, it is possible to prevent a problem in which the antenna is switched many times when it is out of the communication range and the communication state cannot be restored, or the antenna is unnecessarily switched in the out-of-communication state for a short time.

As described above, in the first embodiment, when the transmitter / receiver 106 is out of the communication area when the received electric field strength is below the predetermined level, the CPU 10 is based on the out-of-area information.
8 and the JK flip-flop 109 controls the antenna changeover switch 105 to operate the first transmitting / receiving antenna 10
The first and second transmitting / receiving antennas 102 are switched. This allows the antenna to be automatically switched during wireless communication when it is out of the communication range, depending on the reception status, so even if one of the antennas fails, switching to the other antenna enables transmission and reception, and in an emergency. It is possible to secure communication such as notification of. Further, in the configuration of the present embodiment, the number of antenna changeover switches and changeover circuits does not increase and the circuit scale does not increase, and the antenna changeover function can be realized with a simple configuration.

In the control unit 110 of this embodiment, in addition to the above-mentioned antenna switching when the communication area is out of range or when the antenna fails, the first transmitting / receiving antenna 101 and the second antenna
It is also possible to control the diversity reception by comparing the received electric field strengths of the transmission / reception antenna 102 and selecting the larger antenna. In this case, for example, the transmitting / receiving unit 10
The output Q may be switched by inputting a control signal to the clear input CLR or the preset input PR of the JK flip-flop 109 based on the reception level information from 6.

[Second Embodiment] FIG. 4 is a block diagram showing the arrangement of an antenna switching apparatus according to the second embodiment of the present invention.

The second embodiment is a partial modification of the configuration of the first embodiment described above. In addition to the first transmitting / receiving antenna 101 and the second transmitting / receiving antenna 102,
Further, this is an example in which a reception-only antenna 131 is provided. The reception-only antenna 131 is connected to the antenna connection terminal 133 of the transmission / reception unit 106 by the coaxial cable 132. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the second embodiment, the receive-only antenna 13
1 and the first and second transmitting / receiving antennas 101, 10
It is configured to perform diversity reception with either one of the two. At this time, the transmitting / receiving unit 106 selects the antenna having the larger received electric field strength between the currently selected transmitting / receiving antenna 101 or 102 and the receiving-only antenna 131.

The switching operation between the first transmitting / receiving antenna 101 and the second transmitting / receiving antenna 102 by the control unit 110 and the antenna changeover switch 105 is the same as in the first embodiment. That is, when the communication area where normal transmission / reception is possible is performed, the state in which the first transmitting / receiving antenna 101 in the initial state is selected is held. Then, at the time of reception, the first reception / transmission antenna 101 and the reception-only antenna 131 perform diversity reception.

On the other hand, when the out-of-range information is output from the transmission / reception unit 106 and the communication is out of the communication range, the output Q of the JK flip-flop 109, that is, the antenna switching signal 114 is inverted at the falling timing of the clock signal CLK from the CPU 108. Then, the antenna changeover switch 105 switches the connection from the first transmitting / receiving antenna 101 to the second transmitting / receiving antenna 102. When the communication is switched to the second transmission / reception antenna 102, the second transmission / reception antenna 102 and the reception-only antenna 131 perform diversity reception.

As described above, in the second embodiment, the first transmission / reception antenna 101 and the second transmission / reception antenna 102 are used when the communication area is out of the predetermined reception electric field strength.
To enable transmission / reception so as to return to the communication range, and in the communication range, diversity reception is performed by the transmission / reception antenna 101 or 102 and the reception-only antenna 131 selected at that time. As a result, the reception quality can be improved by diversity reception, and even when one antenna fails, the other antenna can perform communication such as an emergency report.

The following are some modifications of the above-described embodiment. The timing of the clock signal CLK for switching the transmission / reception antenna, which is generated in the CPU 108, can be changed according to the reception state such as the length of the out-of-communication time. For example, when the wireless communication device goes out of the communication range in a short time such as when it enters the tunnel,
By changing the cycle of the clock signal CLK when the antenna is out of the communication area for a relatively long time such as when the antenna is out of the service area or when it goes out of the service area of the base station, the optimum antenna for transmitting and receiving is switched. So that communication can be continued. At this time, in the case of a short out-of-communication range time, the cycle of the clock signal CLK is shortened to switch the antennas quickly, or conversely, the cycle of the clock signal CLK is lengthened to suppress the antenna switching frequency and return to the communication range. The timing can be appropriately set according to the usage situation and settings such as waiting.

The first transmitting / receiving antenna 101 and the second transmitting / receiving antenna 102 are prioritized, and the main transmitting / receiving antenna is given priority as an initial state at an arbitrary timing such as when the power is turned on. It can also be selectable. Also, based on the set priority order, when the communication area state such as standby reception continues, it is possible to preferentially select the main transmission / reception antenna as the initial state at a certain timing. .

The use status of a plurality of antennas, such as the selection state of the first transmitting / receiving antenna 101 and the second transmitting / receiving antenna 102, is displayed on the display unit 115 so that the user can visually judge. You can also

The control unit 11 can switch between the first transmitting / receiving antenna 101 and the second transmitting / receiving antenna 102 by operating the operation unit 116.
When the automatic switching control by 0 is difficult to handle, it is possible to manually switch to an appropriate antenna.

Further, a control signal from a device of a communication partner such as a base station makes it possible to switch between the first transmitting / receiving antenna 101 and the second transmitting / receiving antenna 102, and the transmitting / receiving antenna can be arbitrarily selected by the communication partner. Can be made selectable.

[0044]

As described above, according to the present invention, it is possible to provide an antenna switching device capable of transmitting and receiving by switching the antenna according to the reception state when the communication area is out of range or the antenna is out of order.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an antenna switching device according to a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram showing an antenna switching sequence by the control unit of the present embodiment.

FIG. 3 is an operation explanatory diagram showing the operation of a JK flip-flop provided in a control unit for realizing the antenna switching sequence of FIG. 2 in a truth table.

FIG. 4 is a block diagram showing a configuration of an antenna switching device according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration example of a wireless communication device in a conventional emergency call communication system.

[Explanation of symbols]

100 wireless communication device 101 First transmitting / receiving antenna 102 Second transmitting / receiving antenna 105 antenna selector switch 106 transmitter / receiver 108 CPU 109 JK flip-flop 110 control unit 112 Reception level information 114 antenna switching signal 115 display 116 Operation part 131 reception-only antenna CLK clock signal OS out-of-range signal

Claims (7)

[Claims] 1. A first transmission / reception dual-use antenna and a second transmission / reception dual-use antenna, antenna switching means for selectively connecting and connecting the first and second transmission / reception dual-use antennas, and the first and second A transmission / reception unit that performs wireless communication using a transmission / reception antenna, and based on reception level information in the transmission / reception unit, the antenna switching unit at a predetermined timing when the out-of-communication state in which the reception electric field strength is a predetermined value or less An antenna switching device comprising: a switching control unit that inverts an antenna switching signal input to the switch and switches the first transmitting / receiving antenna and the second transmitting / receiving antenna from one side to the other side. 2. The switching control means, when the out-of-range information indicating the out-of-range communication state is output from the transmitting / receiving means, reverses the antenna switching signal at a timing of a clock signal output for a predetermined time. The antenna switching device according to claim 1, which is characterized in that. 3. The first switching control means selects the first antenna switching signal without changing the antenna switching signal in a communication area state in which the received electric field strength is equal to or higher than a predetermined value.
Alternatively, the connection of the second transmitting / receiving antenna is maintained, and in the out-of-communication state, the first transmitting / receiving antenna and the second transmitting / receiving antenna are connected according to the timing of the clock signal output in a predetermined time. The antenna switching device according to claim 1 or 2, characterized in that the antenna switching device is switched. 4. A reception-only antenna is further provided, and the transmission / reception means performs diversity reception using the first or second transmission / reception antenna selected at that time and the reception-only antenna. The antenna switching device according to any one of Items 1 to 3. 5. The antenna switching device according to claim 2, wherein the switching control means is capable of changing the output timing of the clock signal depending on the reception state. 6. The switching control means can be set so as to select either the first transmitting / receiving antenna or the second transmitting / receiving antenna as an initial state at an arbitrary timing. The antenna switching device according to any one of Items 1 to 4. 7. The switching control means can be set to select either the first transmitting / receiving antenna or the second transmitting / receiving antenna as an initial state when the communication area state continues for a predetermined time. The antenna switching device according to any one of claims 1 to 4, characterized in that.