JP2002319879A - Wireless equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a portable communication terminal whose speech quality can be maintained. SOLUTION: The portable terminal selects an antenna A or B with higher reception strength and connects the selected antenna to a reception section 9 or 8 corresponding to use in the case of receiving a signal by the diversity system. A bit error rate of the received signal is monitored and when the bit rate is deteriorated and the difference between the reception strength of both the antennas A, B is small, the terminal discriminates that a disturbing wave with a directivity takes place and selects a beam antenna system. The terminal uses a tuning circuit 6 or 7, sets an electric length of the corresponding antenna, and combines the antennas A, B to produce the directivity. The directivity excludes the disturbing wave from a received wave. Thus, the antennas A, B provided for the diversity system can effectively be used for the beam antenna system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio apparatus provided with a plurality of antennas and appropriately selecting a better one of these antennas to receive a signal.

[0002]

2. Description of the Related Art Wireless devices such as mobile phones (portable communication terminals)
Sets up a radio communication line with radio waves with the base station,
It communicates by transmitting and receiving voice, data, and the like wirelessly. Therefore, there are a plurality of propagation paths from the base station to the portable communication terminal due to the influence of a building or the like existing near the propagation path between the base station and the portable communication terminal, and radio waves propagated by these paths interfere with each other. This causes fading. Some mobile communication terminals employ a diversity scheme to cope with fading due to multipath. The diversity scheme refers to the reception state (received electric field strength, RS
SI) is appropriately checked, and communication is performed using an antenna having a better reception state (higher reception electric field strength).

[0003]

However, the diversity type portable communication terminal can cope with fading, but cannot overcome the obstacle caused by a sudden interference wave arriving from a specific direction. There has been a problem that the reception sensitivity is suppressed by this interference wave, and the communication state is deteriorated.

[0004] The present invention has been made in view of such a problem, and an object of the present invention is to provide a radio which can maintain good reception quality.

[0005]

According to a first aspect of the present invention, there is provided a diversity radio apparatus for receiving a signal depending on which one of the first antenna (A) and the second antenna (B) has good reception. Determining whether the first antenna (A) and the second antenna (B) have directivity based on a result of detecting an error in the data of the received signal, The signal is received by selecting the directivity of the direction in which the error is small.

A second invention is the first invention, wherein the directional pattern is connected to at least one of the first antenna and the second antenna and changes its own frequency characteristic. (For example, the tuning circuits 6 and 7).

In a third aspect based on the second aspect, the characteristic adjustment circuit is capable of changing its own resonance frequency, and the directivity is controlled by the first antenna or the second antenna. The electrical length of the antenna connected to the characteristic adjustment circuit among the antennas changes in accordance with the change in the resonance frequency.

[0008] A fourth invention provides a first antenna (A),
A second antenna (B) and a receiving unit (8, 9);
A diversity-type radio device for appropriately selecting one of the first antenna (A) and the second antenna (B) having good reception and connecting to the reception unit to receive a signal, Receiving means for receiving a signal by the first antenna (A) and the second antenna (B); detecting means for detecting an error in the data of the received signal; A diversity receiving unit that determines which one of the first antenna (A) and the second antenna (B) receives a signal and performs reception, the first antenna (A) and the second antenna (B). When it is determined from the detected errors that the directivity generated by the second antenna (B) is more advantageous for the reception, the directivity in the direction in which the errors in the data to be received are reduced is determined. 1 a And a beam receiving unit for receiving and caused by the antenna (A) and said second antenna (B).

In a fifth aspect, a first antenna (A) includes:
A second antenna (B) and a receiving unit (8, 9);
A diversity-type radio device for appropriately selecting one of the first antenna (A) and the second antenna (B) having good reception and connecting to the reception unit to receive a signal; Based on a data error in a signal received by at least one of the first antenna (A) and the second antenna (B), the first and second antennas point in a direction to reduce the error. A control unit (11) for determining whether or not to generate directivity, and when the control unit determines to generate the directivity, the first antenna (A) and the second antenna (B). ), And a characteristic adjustment circuit (for example, tuning circuits 6 and 7) for generating the directivity by the action described above.

In a sixth aspect based on the fifth aspect, the characteristic adjustment circuit changes the electrical length of the first antenna or the second antenna, thereby changing the first antenna or the second antenna.
And the second antenna has the directivity.

In a seventh aspect based on the sixth aspect, the characteristic adjustment circuit includes an electrical length setting section (for example, electrical length switching circuits 20A, 20A) for setting an electrical length of the connected antenna.
B) and a switching element (SWA, SWB) for conducting one of the first antenna and the second antenna to the receiving unit and the other to the electrical length setting unit.
And.

In an eighth aspect based on the seventh aspect, the electric length setting section includes a resonance circuit having a capacitor and a coil, and the control section controls the capacitance of the capacitor. Sets the electrical length.

In a ninth aspect based on the eighth aspect, the capacitor is a variable capacitance diode, and the control unit sets the electrical length by changing a voltage applied to the variable capacitance diode. .

A tenth invention is any one of the first to ninth inventions, wherein the degree of the error is determined based on a bit error rate.

In the above description, reference numerals in parentheses illustrate correspondence with the configuration of the embodiment. These references are not intended to unnecessarily limit the scope of the claims.

[0016]

According to the first aspect of the present invention, it is determined whether or not the first antenna and the second antenna have directivity based on the result of detecting an error in the data of the received signal. However, since the signal is received by selecting the directivity in the direction with less error in the received data, it is possible to switch the presence or absence of the directivity for the interference wave arriving from a specific direction and perform appropriate reception Becomes This maintains the quality of the reception.

In the second aspect, the directivity is brought about by the change in the frequency characteristic of the characteristic adjustment circuit.
By adding a characteristic adjustment circuit, the wireless device of the present invention can be easily realized.

In the third aspect, the directivity is provided by the change in the electrical length of the first antenna or the second antenna due to the change in the resonance frequency. Since the antenna becomes a reflector or a reflector and has directivity, directivity can be generated by using a plurality of antennas used for diversity reception.

According to a fourth aspect, a receiving means for receiving a signal by the first antenna and the second antenna, a detecting means for detecting an error in data of the received signal, A diversity receiving means for deciding which of the first antenna and the second antenna to receive a signal and performing reception, and generating directivity by the first antenna and the second antenna. If it is determined from the detected error that the reception is more advantageous for reception, the first antenna and the second antenna generate directivity in a direction in which errors in received data are reduced. Since there is provided a beam receiving means for performing reception, it is determined whether a data error of a received signal is detected and diversity reception is performed, or reception (beam reception) is performed with directivity. Constant to, from doing a proper reception, it is possible to maintain the quality of the received successfully.

In the fifth invention, based on a data error of a signal received by at least one of the first antenna and the second antenna, the first and second antennas reduce the error based on the data error. A control unit that determines whether or not to generate directivity, and when the control unit determines to generate the directivity, the directivity is reduced by an action of the first antenna and the second antenna. Since a directivity is provided by the characteristic adjustment circuit connected to the first antenna and the second antenna, a plurality of antennas used for diversity reception are used. Thus, directivity can be generated, and reception with good quality can be performed.

In the sixth aspect, the characteristic adjustment circuit causes the first antenna and the second antenna to have directivity by changing the electrical length of the first antenna or the second antenna. Since one antenna becomes a director or a reflector with respect to the other antenna and has directivity, directivity can be generated using a plurality of antennas used for diversity reception.

[0022]

FIG. 1 is a block diagram illustrating the configuration of a portable communication terminal (an example of a wireless device) according to the present embodiment. The mobile communication terminal is provided with two antennas A and B. As the antenna A and the antenna B, a whip antenna or an inverted F antenna,
It is possible to use a chip antenna in which the inverted F antenna is downsized. In the present embodiment, a configuration in which directivity is generated using a plurality of antennas originally provided for diversity reception will be described.

The antennas A and B in FIG. 1 are used for signal reception, and the antenna B is also used for signal transmission. First, a conventional configuration for transmission will be described. The portable communication terminal is provided with a transmission section 12, where the acoustic signal is converted into an audio signal. The audio signal is sent to the audio processing unit 10 and encoded under the control of the control unit 11 to generate a baseband signal. The baseband signal is then sent to the radio section 3. Specifically, the baseband signal is sent to the transmission unit 5 of the wireless unit 3, and a high-frequency signal is generated. At the time of transmission, the switch 4 connects the antenna B and the transmission unit 5, and a high-frequency signal is emitted from the antenna B as a radio signal.

Next, the components related to reception will be briefly described. Antenna A is connected to tuning circuit 7. The antenna B is switched by the switch 4, and is connected to the transmitting unit 5 at the time of transmission and to the tuning circuit 6 at the time of reception as described above. A receiving circuit 8 and a receiving circuit 9 are connected to the subsequent stage of the tuning circuit 6 and the tuning circuit 7, respectively. The tuning circuit 6 and the tuning circuit 7 are controlled by the control unit 11, and take the following three states, respectively.

The antenna and the receiving circuit are connected. -L Increase the electrical length of the antenna. -H Reduce the electrical length of the antenna.

As described above, since the three states can be selected, the portable communication terminal of the present embodiment has a diversity system in which each antenna is selectively used, and a beam in which directivity is generated by each antenna. Both types of reception can be switched. The mobile communication terminal according to the present embodiment is characterized in that the two systems can be switched. Here, the beam system refers to a system in which the antenna A and the antenna B constitute one directional antenna, and the one antenna has directivity to perform reception. For example, by adjusting the electrical length of one of the antennas A and B and using the antenna as a reflector or a director, it is possible to impart directivity to this set of antennas. Hereinafter, two methods will be described.

When diversity reception is performed, the received signal strength (RSSI) of each of antennas A and B is detected during the antenna switching diversity level measurement time before the reception slot. First,
The tuning circuit 6 and the tuning circuit 7 are set to the above state by the control unit 11. Then, the two high-frequency signals transmitted from the antennas A and B are input to the receiving units 8 and 9, respectively. Receiving section 8 and receiving section 9 respectively receive signals transmitted from the base station. Further, in the receiving unit 8 and the receiving unit 9, amplification and frequency conversion are performed on the extracted high-frequency signal, and a baseband signal is generated.

The control section 11 receives the received signal strengths of the antennas A and B from the receiving sections 9 and 8, respectively. Then, in the reception slot after the antenna switching diversity level measurement time, the control unit 11 instructs the audio processing unit 10 to perform reception by the antenna A or the antenna B having the higher received signal strength. The voice processing unit 10 receives a baseband signal from the receiving unit 8 and the receiving unit 9 corresponding to the designated antenna (the designated receiving unit), generates a voice signal, and sends the voice signal to the receiving unit 13 (speaker). give. And
An acoustic signal is generated in the receiver 13 and the sound is reproduced. In diversity reception, the above processing is repeated for each slot.

The reason why the diversity reception is effective is that the received signal strength temporally fluctuates with the movement due to the spatial fluctuation of the received signal strength of the signal (received wave) transmitted from the base station. And antenna A and antenna B
This is the case where there is a difference between the received signal strengths. Therefore, when such a condition is not satisfied, the diversity system cannot perform good reception. For example, there is a case where the reception state of both antennas A and B deteriorates due to the generation of a sudden interference wave arriving from a specific direction. That is, it is located in the service area, the electric field strength is uniformly high, and the difference between the received signal strengths of the antennas A and B is small,
This is a case where an error has occurred in a received signal due to an interference wave or the like and reception fails.

In order to cope with such a situation, how much error has occurred in the received signal is shown in FIG.
Is configured to be grasped by the control unit 11. The control unit 11 receives the redundant information (for example, an error correction code) given to the signal from the receiving unit 8 or the receiving unit 9 and based on the received redundant information (for example, BE error rate code).
R). If a reception failure occurs due to an interference wave or the like, the received signal strength (RSS
I) is good, but the BER is high. Therefore,
By knowing the BER, it is possible to estimate the occurrence of an interference wave or the like.

In the portable communication terminal of the present embodiment,
The diversity system is configured to switch to the beam system if reception is not successful, which is a feature of the diversity system. That is, by switching to reception with directivity directed in a direction to avoid the interference wave, the influence of the interference wave is avoided. How switching is determined will be described later in detail with reference to FIG.

When the beam system reception is performed, the tuning circuit 6 and the tuning circuit 7 can take any of the above-mentioned states, the state -L or the state -H. The control unit 11 performs control such that one of the antennas A and B having a good reception state is connected to the reception unit and used as a feed element, and the other is used as a reflector or a director to generate directivity. Do. In order to realize such a configuration, each of the tuning circuit 7 and the tuning circuit 6 may be configured as exemplified in FIGS. 2 and 3, for example.

FIGS. 2 and 3 are schematic diagrams illustrating the circuit configurations of the tuning circuit 7 and the tuning circuit 6, respectively. The tuning circuit 7 and the tuning circuit 6 have the same configuration as each other, and are different in that the connection destinations are different and that the control is performed independently. Therefore, the tuning circuit 7 will be described first with reference to FIG. 2, and then the tuning circuit 6 will be described with reference to FIG. 3 focusing on the difference from the tuning circuit 7.

As exemplarily shown in FIG. 2, the tuning circuit 7 is provided with a switching element SWA.
The antenna A is connected to either the (switch position 1 side) or the electrical length switching circuit 20A (switch position 2 side). The electric length switching circuit 20A has a coil having one end connected to the switch position 2 side, and a plurality of electric elements connected in parallel to each other connected in series to the other end. And these components constitute a resonance circuit.

The portion of the resonance circuit where the electric elements are connected in parallel includes a portion where a coil and a capacitor for cutting current are connected in series, and a portion where a variable capacitor (in this example, a varicap is used) for changing the resonance frequency. (Implemented by a diode) and a capacitor connected in parallel to secure the capacity of the resonance circuit even when the capacity of the variable capacitor is reduced. One end of these circuit elements is grounded, and the other end is connected to a resistor in addition to the coil described above. The other end of the resistor is a terminal of the electrical length switching circuit 20A, and two kinds of voltages can be applied by a voltage source such as a D / A converter controlled by the control circuit 11.

The two types of voltages are an "H" level voltage (e.g., 4 V) higher than a reference voltage (e.g., 2.5 V) and a "L" level voltage (e.g., 1 V) lower than a reference voltage (e.g., 1 V).
V). When the magnitude of the applied voltage is changed in two ways, the capacitance of the variable capacitor changes, thereby changing the resonance frequency of the resonance circuit. When the antenna A is connected to the position 2 of the switching element SWA, the resonance frequency of the antenna A changes, and the electrical length of the antenna at the reception frequency changes.

More specifically, when an H-level voltage is applied to the terminal TA, the capacitance of the variable capacitor decreases, the electrical length of the antenna A decreases, and the antenna A Functions as a vessel. On the other hand, when an L-level voltage is applied, the capacitance of the variable capacitor increases, the electrical length of antenna A increases, and antenna A functions as a reflector for antenna B.

The tuning circuit 6 shown in FIG. 3 also has the tuning circuit 7 shown in FIG.
The switching element SWB connects the antenna B to either the receiving unit 8 or the electrical length switching circuit 20B. Terminal TB of electric length switching circuit 20B
Is supplied with an H level or L level voltage under the control of the control circuit 11, and the antenna B functions as a director or a reflector with respect to the antenna A.

In the example of FIG. 1, a tuning circuit 7 and a tuning circuit 6 and a receiving section 9 and a receiving section 8 are provided for the antennas A and B, respectively.
Only one tuning circuit and one receiving unit may be provided, and these may be switched and connected to the antenna A and the antenna B for common use. In this case, a switch for switching the connection of the antenna A and the antenna B to the tuning circuit and the receiving circuit, respectively, is required.

In this case, when measuring the antenna switching diversity level, the antennas A and B
Are sequentially connected to obtain the received signal strength and BER of each antenna, and these are compared by the control circuit 11. When receiving by the beam system, one of the antennas A and B may be connected to a receiving unit to serve as a feed element, and the other may be connected to a tuning circuit to change its electrical length.

The following describes how to set the switching elements SWA and SWB of FIGS. 2 and 3 and the level of the voltage applied to the terminals TA and TB to properly use the antennas A and B. A description will be given of the possibility.

FIG. 4 is a diagram exemplifying specific settings for the diversity system and the beam system. When performing reception by the diversity scheme, as illustrated in FIG.
Both the switching element SWA and the switching element SWB in FIGS. 2 and 3 are set to the position 1 side. Thereby, antenna A and antenna B
Are connected to the receiving circuit 9 and the receiving circuit 8, respectively, to enable diversity reception.

When performing reception by the beam method, four settings are possible. This depends on which of the antenna A and the antenna B is used as the feed element,
This is because in each case, two cases occur depending on whether the remaining one is used as a reflector or a waveguide, resulting in four cases.

First, the case where the antenna B is used as a feeding element and the antenna A is used as a reflector will be described as an example. As for the antenna B used as the feed element, the switching element SWB shown in FIG.
Is set to the position 1 side, and the antenna B is connected to the receiving unit 8. For the antenna A used as a reflector, the switching element SWA in FIG. 2 is set to the position 2 side to connect to the electric length switching circuit 20A, and the L level signal is connected to the terminal TA in order to increase the electric length. give.

On the other hand, when the antenna A is used as a director, the signal applied to the terminal TA in the above setting may be changed to the H level. That is, the switching element SWB is set to the position 1 side, and the antenna B is connected to the receiving unit 8. As for the antenna A used as a reflector, in order to shorten the electrical length, the switching element SWA is set to the position 2 and connected to the electrical length switching circuit 20A, and an H level signal is given to the terminal TA. As a result, the electrical length of the antenna A is shortened, and the antenna A
Functions as a director.

As understood from the above description, the switching element may be set to the position 1 side for the antenna serving as the feed element. For the remaining antennas, the switching element is set on the position 2 side, and the level of the signal applied to the terminals TA and TB is "L" when used as a reflector, and "L" when used as a director. H ”.

With the configuration described above, the diversity system and the beam system are automatically switched under the control of the control circuit 11 in FIG. 1 according to the reception state. here,
There are various ideas about which of the four combinations in the beam system of FIG. 4 is to be selected. For example, the control circuit 11 obtains the BER for all four combinations, and the control circuit 1 determines the combination that gives the minimum BER.
1 can be selected for reception. In addition, the reception state (B
ER) is measured, and if a combination that gives a BER smaller than the value set in advance as a criterion is found, this combination is adopted, and B is used for the remaining combinations.
It is also possible to adopt a method that does not require the ER. As an example, a description will be given below of the processing procedure in the latter case.

FIG. 5 is a flowchart illustrating a processing procedure in the portable communication terminal of the present embodiment. As shown in the figure, when the power is turned on, step S1 is executed.
At 01, the control circuit 11 of FIG. 1 selects the antenna A or the antenna B designated in the initial setting as the current receiving antenna.

Next, in step S102, the control circuit 11 receives a signal from the base station, and determines whether or not the signal from the base station has been received. It is determined whether it exists in the service area. If “YES” is determined, it is determined that the mobile communication terminal is in the service area and a call is possible, and a call is started in step S103. On the other hand, if "NO" is determined, the mobile communication terminal is in a range where radio waves from the base station do not reach (outside the service area) and a call is not possible, so the mobile communication terminal moves into the service area. Until you can make a call
Subsequently, in step S102, the process of searching for a radio wave from the base station is repeated.

Step S1 subsequent to step S103
At 04, the received signal levels of the antennas A and B are measured during the antenna switching diversity level measurement. Subsequent step S10
In 5, the control circuit 11 determines whether or not the BER is 10 ⁻³ or more in order to know whether or not an interference wave exists. The reason why the occurrence of an interference wave is determined using the BER is that when an interference wave is generated, it is naturally expected that the BER will deteriorate even if the received signal strength (RSSI) does not deteriorate. is there. Here, “10 ⁻³ ” is set as an example of the upper limit of the allowable error, and another value can be adopted.

If "NO" is determined in the step S105, it is determined that the BER is within the allowable range and a call of sufficient quality is possible even with the current setting, and the process proceeds to the step S108 without changing the setting. I do. On the other hand, “YES”
If it is determined that the BER is out of the permissible range and the quality of the call is low in the current setting, it is determined that the antenna setting needs to be changed to an appropriate antenna setting to obtain a good received signal. Proceed to S106. If the received signal strength is high, but the BER is bad (out of the permissible range), it is presumed that an interference wave exists for the desired wave from the base station, and the interference wave is removed effectively. It is necessary to set the state of the antenna.

Even if the occurrence of an interfering wave is estimated in step S105, if the difference in the intensity of the received signal between antennas A and B is large, the interruption of the radio wave due to fading is more effective for the reception than the interfering wave. A large impact. In such a case, it is preferable to perform reception not by the beam method but by the diversity method. Therefore, in step S106, it is determined whether or not the difference in reception intensity between antenna A and antenna B is 10 dB or more. Also here, the value of “10 dB” is an example as a measure of the occurrence of an interfering wave or the like, and another value can be adopted according to circumstances. Step S1
In 06, it is determined whether to receive in a diversity system or to receive with directivity in a beam system based on the "difference" of the received signal for each antenna, but whether to receive in a diversity system based on the received signal strength itself. Alternatively, it may be determined whether the reception is performed with the directivity provided by the beam method. In other words, when the received signal strength is high, but the quality of the received signal is poor (the BER is bad), it can be determined that the influence of the interference wave has occurred. To receive the signal from the base station.

If the effect of fading is dominant, the control circuit 11 determines "Y" in step S106.
ES ”is determined, and the process shifts to step S107. Under the diversity scheme, the setting is switched such that the antenna A or the antenna B with the higher received signal strength is connected to the receiver, and reception is performed. On the other hand, if the influence of the directional interfering wave or the like is dominant and the reception cannot be performed satisfactorily, "NO" is determined in the step S106, and the process shifts to the step S110 to perform the reception by the beam system.

In the steps after step S110, reception is sequentially performed using the above-described four combinations of the beam system, the reception quality is checked, and a predetermined reference (BE
R is smaller than 10 ⁻³ ), and the processing is performed in such a manner that the combination is adopted at the time of finding one satisfying the condition. Here, for example, there are two combinations of giving directivity from antenna B to antenna A, such that (antenna A, antenna B) = (director, feed element) or (feed element, reflector). There are two combinations that provide directivity suitable for reception. Therefore, FIG.
In the example, the combination that should have been tried after the combination actually selected may have better reception quality.

First, in step S110, BER is obtained with antenna A set as a reflector and antenna B set as a feed element. In step S111, it is determined whether this BER is less than 10 ^-3 . “Y
ES ”, it is determined that the reception quality is sufficient, and in order to perform reception in this combination, step S1 is performed.
Move to 19. If "NO" is determined, the next combination is tried, assuming that reception cannot be performed satisfactorily with the current combination.

Thus, after step S112,
A combination of antenna B as a reflector, antenna A as a feed element (step S112), antenna A as a director,
Combination of antenna B and feed element (step S
114), a combination of antenna B as a director and antenna A as a feed element (step S116) is tried in order based on the switching pattern of FIG.
^-3 "(steps S113, S11
5, S117) is repeated. Of course, such an order is merely exemplary.

In this example, for example, in step S110, the antenna A is set as a reflector, and in step S11
In 2, the antenna B is set as the reflector. That is, the antenna serving as the feeding element and the antenna serving as the reflector or the director are changed every time one combination is tried. However, by setting one antenna as a feed element and changing the other antenna from a director to a reflector (or a reflector to a director), the directivity was reversed, and one that satisfied the evaluation conditions was found. If not, the same processing may be repeated using the other antenna as a feed element. By setting the order in this way, as illustrated in FIG.
It is possible to reduce the number of times the switches SWA and SWB are switched.

Further, there is a difference in antenna gain between antennas A and B, for example, when one is a whip antenna and the other is a chip antenna,
In a case where a difference in reception sensitivity occurs, it is preferable to set a higher reception sensitivity as a feed element in an early step. This is to improve the quality of the call by making the call with the better sensitivity.

In the above processing, “BER <10 ⁻³ ”
If no combination that satisfies the condition is found, the process moves from step S117 to step S118. In step S118, the combination having the lowest BER is selected from the four combinations tested in the above processing, and the antenna A is selected based on the combination.
And the state of the antenna B are set. Such a process can be realized by providing the control unit 11 of FIG. 1 with a BER storage unit and causing the control unit 11 to compare four BERs.

In the state where the settings of the antennas A and B are determined and the directivity is determined as described above, in step S119, reception is performed by the beam system having directivity.

The directivity determination procedure described above (S110 to S110)
In S118), if the reception quality is better than a predetermined value (BER <10 ⁻³ ), the reception is configured in that state. However, the reception quality is confirmed for all four combinations, and Good reception quality may be selected.

After step S119, step S105 and step S107, it is determined in step S108 whether or not to continue the call. This decision
This is performed based on whether or not the end signal is output. When the end signal is not generated and the call is continued, it is determined to be “YES”. In order to continue the call, the process returns to step S104, and the reception is performed in the antenna switching diversity level measurement time in the next slot. Measure the level. That is, steps S104 to S108 correspond to processing for one slot. On the other hand, if "NO" is determined in the step S108, the call ends in a step S109. The above is an example of the procedure of the process performed by the control circuit 11.

Next, examples of mounting positions of a plurality of antennas will be described. FIG. 6 shows two whip antennas A1 and B
1 (solid line) is a perspective view showing an example in which the polarization planes are the same and they are mounted side by side (the figure shows a state in which whip antennas A1 and B1 are housed in a portable communication terminal). FIG. 7 is a perspective view showing an example in which two chip antennas A2 and B2 (dotted lines) have the same plane of polarization and are mounted side by side. By providing a plurality of antennas along a direction perpendicular to the longitudinal direction of the mobile communication terminal as illustrated, when the mobile communication terminal is used in a beam system, the directivity of the two antennas is in the horizontal direction. That is, it is easy to catch a desired wave arriving from the horizontal direction and to easily remove an interfering wave arriving from the horizontal direction. However, arranging the two antennas in a direction perpendicular to the longitudinal direction is intended to sufficiently exert the effect of the mobile communication terminal of the present embodiment. That doesn't mean you can't catch radio waves.

Further, the two chip antennas in the example of FIG. 7 are arranged side by side on the widest plane (rear side) among the six side surfaces inside the main body of the portable communication terminal. It is also possible to adopt a configuration in which chip antennas are attached one by one along a surface and a left side surface facing the surface. Here, in the examples of FIGS. 6 and 7, the two antennas are arranged so that the polarization planes are the same, but this aims at maximizing the effect by making them the same. is there. The effect can be obtained if the antennas are arranged so that the polarization planes are aligned to the extent that the desired wave can be received.

Further, in the examples of FIGS. 6 and 7, two antennas are respectively mounted, but it is naturally possible to mount three or more antennas. When receiving by the beam method, when there are only two antennas, only two directions on a single direction can be selected as the directivity. However, directivity can be set along a plurality of directions by arranging three or more antennas so that they do not all exist on the same straight line. Even when the user changes the angle at which the portable communication terminal is held, it is possible to cope with the change by changing the combination, and it is possible to always realize a high quality call.

In such a case, the antenna having the highest received signal strength is selected when receiving by the diversity system, and _n P ₂ (two out of n antennas) when receiving by the beam system. Is the number of permutations to be extracted by distinguishing the order, and n is an integer equal to or greater than 2 which is the total number of antennas) and a combination that can perform good reception is selected.

In the above example, one of the antennas is used as a director or a reflector in the beam system in which the antennas have directivity. Is possible. For example, antenna A and antenna B can be used as a set of adaptive antennas. In this case, the control circuit 11 adjusts the phase difference between the tuning circuit 6 and the tuning circuit 7 so that a signal of a desired frequency can be extracted. By adjusting the value of the difference, the directivity can be selected.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a mobile communication terminal.

FIG. 2 is a circuit diagram illustrating the configuration of a tuning circuit 7;

FIG. 3 is a circuit diagram illustrating the configuration of a tuning circuit 6;

FIG. 4 is a diagram exemplifying a combination of the tuning circuit 7 and the settings of the tuning circuit 6 in FIGS. 6 and 7, respectively;

FIG. 5 is a flowchart illustrating a processing procedure of the mobile communication terminal.

FIG. 6 is a perspective view showing a first example of mounting an antenna.

FIG. 7 is a perspective view showing a second example of mounting an antenna.

[Explanation of symbols]

 6,7 Tuning circuit 8,9 Receiver 11 Receiver A, B Antenna S101-S119 Step SWA, SWB Switching element

Claims (10)

[Claims] 1. A diversity-type radio device for receiving a signal by a first antenna or a second antenna having a better reception, based on a result of detecting an error in data of the received signal. And determining whether or not the first antenna and the second antenna have directivity, and selecting a directivity in a direction with less error in received data to receive a signal. Machine. 2. The radio device according to claim 1, wherein the directivity is connected to at least one of the first antenna and the second antenna, and changes its own frequency characteristic. Wireless device further comprising a characteristic adjustment circuit that brings about. 3. The wireless device according to claim 2, wherein the characteristic adjustment circuit is capable of changing its own resonance frequency, and the directivity is the first antenna or the second antenna. A wireless device provided by changing an electrical length of the one connected to the characteristic adjustment circuit according to a change in the resonance frequency. 4. A first antenna, a second antenna,
A diversity radio having a receiving unit, and appropriately selecting one of the first antenna and the second antenna that has good reception and connecting to the receiving unit to receive a signal. Receiving means for receiving a signal by a first antenna and a second antenna; detecting means for detecting an error in the data of the received signal; and the first antenna or the Among the second antennas, a diversity receiving unit that determines which antenna receives a signal and performs reception, and a method in which directivity is generated by the first antenna and the second antenna is used for reception. Advantageously, when it is determined from the detected error, the directivity of the direction in which the error of the data to be received is reduced is given to the first antenna and the second antenna. A radio device comprising: a beam receiving unit configured to generate and receive a signal. 5. A first antenna, a second antenna,
A diversity radio having a receiving unit, and appropriately selecting one of the first antenna and the second antenna that has good reception and connecting to the receiving unit to receive a signal. Based on a data error in a signal received by at least one of the first antenna and the second antenna, whether directivity is produced by the first and second antennas in a direction to reduce the error. A control unit that determines whether the directivity is generated, and a characteristic adjustment circuit that generates the directivity by the action of the first antenna and the second antenna when the control unit determines that the directivity is generated. A wireless device comprising: 6. The wireless device according to claim 5, wherein the characteristic adjustment circuit changes the electrical length of the first antenna or the second antenna, thereby changing the first antenna and the second antenna. A radio device for causing the directivity to occur in a second antenna. 7. The wireless device according to claim 6, wherein the characteristic adjustment circuit sets an electrical length of a connected antenna, and the first antenna or the second antenna Of which
And a switching element for conducting one to the receiving unit and the other to the electrical length setting unit. 8. The wireless device according to claim 7, wherein the electric length setting unit includes a resonance circuit having a capacitor and a coil, and the control unit controls the capacitance of the capacitor to control the electric length. A radio that sets the electrical length. 9. The wireless device according to claim 8, wherein the capacitor is a variable capacitance diode, and wherein the control unit changes the voltage applied to the variable capacitance diode to set the electrical length. Machine. 10. The wireless device according to claim 1, wherein the degree of the error is determined based on a bit error rate.