JP2010056844A - Mobile communication terminal and antenna selection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication terminal for obtaining reception diversity gain more effectively. <P>SOLUTION: A mobile communication terminal includes a reception diversity function and allows for a change in relative positional relationship among at least three antennas. The mobile communication terminal includes: an antenna switch 205 for selecting one pair of antennae from among at least three antennae (101-103); a measuring means (204, 208) for measuring a gain difference between the antennae of the selected pair of antennae; and a control means (208-211) for determining an antenna pair to be used for reception diversity based on the distance between antennae which is determined by their relative positional relationship and a gain difference between antennae in each antenna pair. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mobile communication terminal such as a mobile phone, and more particularly to an antenna selection method for a mobile communication terminal having at least three antennas.

  Various techniques for improving the diversity effect of a plurality of built-in antennas have been proposed for portable communication terminals in which the shape of the terminal housing changes, such as a folding type, a sliding type, or a revolver type.

  For example, the foldable mobile communication terminal disclosed in Patent Document 1 employs a configuration in which the polarization planes of two antennas are separated from each other at the time of use (third column paragraph 0021, etc.).

  Patent Document 2 also discloses a portable wireless terminal (see paragraphs 0021 to 0022 on page 5) that selects any two of the three antennas and adopts a combined diversity transmission / reception method, and a case in which the housing is open. Discloses a portable radio terminal (see paragraphs 0031 to 0032 on page 6) in which a combined diversity transmission / reception method is selected and a selection diversity transmission / reception method is selected that selects an antenna with a higher reception level when the housing is closed. ing.

JP 2001-230614 A JP-A-2005-244260

  However, recent mobile communication terminals are equipped with various functions, and accordingly, the shape of the terminal housing is also diversified. For example, even if it is a foldable type, the hinge can be rotated in two axial directions, and the display can be rotated horizontally or can be closed with the display exposed. Along with this, various cases have been assumed in which the user holds the terminal.

  In various usage situations of such terminals, as in Patent Documents 1 and 2 described above, it is not possible to sufficiently obtain the effect of reception diversity simply by corresponding to the opening and closing of the casing. This is because the reception level may change depending on the antenna depending on the state in which the user holds the terminal by hand.

  Accordingly, an object of the present invention is to provide an antenna selection method and a mobile communication terminal using the antenna selection method for more effectively obtaining a reception diversity gain.

  The mobile communication terminal according to the present invention is a reception diversity compatible mobile communication terminal capable of changing the relative positional relationship of at least three antennas, and antenna selection means for selecting one antenna set from the at least three antennas, Measuring means for measuring the gain difference between the antennas of the selected antenna set, and determining the antenna set used for reception diversity based on the distance between the antennas determined according to the relative positional relationship and the gain difference between the antennas of each antenna set; Control means for controlling the antenna selection means.

    An antenna selection method according to the present invention is an antenna selection method in a reception diversity compatible mobile communication terminal capable of changing a relative positional relationship of at least three antennas, and detects a current relative positional relationship of the at least three antennas. And measuring the gain difference between the antennas of each of the at least three antennas, and selecting the antenna set to be used for reception diversity based on the distance between the antennas determined according to the relative positional relationship and the gain difference between the antennas. It is characterized by.

  According to the present invention, a reception diversity gain can be obtained more effectively.

1. Embodiments According to one embodiment of the present invention, depending on the terminal shape, such as a mobile phone having a folding mechanism corresponding to a reception diversity function, a mobile phone having a slide mechanism, or a mobile phone having a revolver mechanism. In a mobile communication terminal that can change the relative positional relationship of antennas, the terminal shape and the antenna correlation are correlated, and the gain difference between the antennas is measured to obtain a combination that always realizes optimal reception diversity. It becomes possible.

  Specifically, the following policy is given to realize antenna selection for obtaining a reception diversity gain more effectively.

(1) The change in the distance between the antennas depending on the open / close state is used as a condition for antenna selection as a parameter indicating the change in the correlation between the antennas.

(2) An RSSI (Received Signal Strength Indicator) of an incoming wave received by each antenna is used as a condition for antenna selection as a parameter indicating a change in gain difference between antennas.

  These two parameters are determined to determine a set of two antennas used for receive diversity. Further, the determination of these antenna sets functions even when the mobile communication terminal is communicating, and the combinations can be dynamically changed. Hereinafter, embodiments of the present invention will be described in detail.

2. FIG. 1 is a diagram showing a structure and antenna arrangement of a mobile communication terminal according to an embodiment of the present invention, in which (A) is a side view in a closed state, (B) is a plan view in a closed state, ) Is a side view in an open state. The mobile communication terminal according to the present embodiment has a structure in which a first housing 10 and a second housing 11 are connected to each other by a hinge portion 12 so as to be foldable. Two receive-only antennas 102 and 103 are mounted.

  A transmission / reception antenna 101 is mounted on the tip of the first housing 10, a reception-only antenna 102 is mounted on the hinge-side end, and a reception-only antenna 103 is mounted on the tip of the second housing 11. Therefore, the distance between the transmission / reception antenna 101 and the reception-dedicated antenna 102 is fixed, but the distance between the transmission / reception antenna 101 and the reception-dedicated antenna 103 changes according to the terminal shape. That is, the spatial relative positional relationship of the antennas 101-103 changes according to the opening / closing of the terminal housing.

  Specifically, in the closed state as shown in FIG. 1A, the distance between the transmission / reception antenna 101 and the reception dedicated antenna 102 is larger than the distance between the transmission / reception antenna 101 and the reception dedicated antenna 103. On the other hand, in the open state as shown in FIG. 1C, the distance between the transmission / reception antenna 101 and the reception-dedicated antenna 103 is larger than the distance between the transmission / reception antenna 101 and the reception-dedicated antenna 102. .

  The transmission / reception antenna 101 is used for transmission / reception, but one of the reception-only antennas 102 and 103 is selected, and a reception diversity function is realized in combination with the transmission / reception antenna 101. That is, any combination of the antenna set of the transmission / reception antenna 101 and the reception dedicated antenna 102 (hereinafter referred to as antenna set A) or the antenna set of the transmission / reception antenna 101 and the reception dedicated antenna 103 (hereinafter referred to as antenna set B). Receive diversity gain is obtained by simultaneously receiving and combining both paths.

  In general, the greater the distance between antennas, the lower the reception path correlation, and the more likely it is to benefit from reception diversity. Therefore, generally, in the closed state of FIG. 1A, the antenna set A of the transmission / reception antenna 101 and the reception-only antenna 102 is selected, and in the open state of FIG. 1C, the transmission / reception antenna 101 is selected. It is considered desirable to select the antenna set B of the reception-only antenna 103 to obtain the diversity gain.

  However, as already mentioned, in recent mobile phones, it is possible to adopt not only the open / closed state but also three- and four-shaped styles, such as a TV viewing mode, and simply opening and closing between two antennas. The correlation cannot be determined.

  In addition, the gain of the antennas 101 to 103 is not always the same depending on the state in which the user uses the mobile phone. Variations can occur. Therefore, in order to maximize the effect of reception diversity, it is important to take into account the inter-antenna correlation and the inter-antenna gain difference at the same time.

  As described above, in general, the reception diversity effect increases as the distance between antennas increases, and the reception diversity effect decreases as the gain difference between antennas increases. Therefore, it is possible to select two antenna sets A or B so as to maximize the diversity effect using both the distance between the antennas and the gain difference as parameters. By executing the antenna switching control in this way, it is possible to obtain an optimal antenna combination with respect to the reception diversity effect. Details will be described below.

2.1) Configuration FIG. 2 is a block diagram showing a functional configuration of the mobile communication terminal according to the present embodiment. Here, a functional configuration related to the present invention is schematically illustrated, and an operation unit, a display unit, and the like of the mobile communication terminal are omitted.

  In FIG. 2, the transmitting / receiving antenna 101 is connected to a duplexer 201, and the duplexer 201 is connected to the RF system 204 via filters 202 and 203. The reception RF signal is output from the duplexer 201 to the RF system 204 via the filter 202, and the transmission RF signal is output from the RF system 204 to the duplexer 201 via the amplifier 203.

  Also, the receive-only antennas 102 and 103 are connected to the antenna switch 205, and the received RF signal from the selected receive-only antenna is output to the RF system 204 through the filter 206.

  The RF system 204 demodulates the RF signal received by the selected reception-only antenna 102 or 103 and the transmission / reception antenna 101 and outputs the demodulated signal to the baseband processing unit 207. Further, the RF system 204 outputs the strength (RSSI) of these received signals to a program control processor (hereinafter referred to as CPU) 208. A high speed AGC function is used for RSSI measurement. The received data is synthesized by the baseband processing unit 207 and output to the CPU 208.

  CPU 208 controls the overall operation of the mobile communication terminal. According to the present embodiment, the CPU 208 uses the RSSI measurement value, the random access memory (RAM) 209, the nonvolatile memory 210, and the terminal shape detection unit 211 to switch the antenna of the antenna switch 205 so as to maximize the reception diversity effect. Take control.

  The RAM 209 stores data indicating the current terminal shape (open / closed state here) detected by the terminal shape detection unit 211. The terminal shape detection unit 211 detects the open / closed state of the first housing 10 and the second housing 11 constantly or periodically, and when the shape changes, the terminal shape data in the RAM 209 is updated. The method for detecting the terminal shape is not particularly limited. For example, the terminal shape is specified by detecting the rotation of the hinge portion 12 or the change in magnetic field strength associated with the opening and closing of the first housing 10 and the second housing 11. Can do.

  The non-volatile memory 210 stores a matrix indicating the relationship among the terminal shape, the correlation / gain difference of each antenna set, and the diversity gain. This matrix is obtained to some extent by experiments and can be changed in the development process of the mobile communication terminal. As described above, since the distance between the two antennas of each antenna set is determined by the terminal shape of the mobile communication terminal, it can be associated with the correlation value. This shape-correlation value association can be obtained by experiment and differs depending on the model of the mobile communication terminal. Here, it is assumed that the direct relationship between the terminal shape and the correlation value is obtained by a typical experiment (for example, a measurement value in a uniform incoming wave). This shape-correlation value correspondence can also be changed in the development process of the mobile communication terminal.

2.2) Antenna Selection Control at Communication Channel Setting FIG. 3 is a flowchart showing antenna selection control at the time of communication channel setting in the mobile communication terminal according to the present embodiment. First, immediately before setting a communication channel for starting continuous communication, the current detected shape of the terminal shape detecting unit 211 is stored in the RAM 209 (step 301). Subsequently, the CPU 208 switches the antenna switch 205 at high speed to input the reception signal strength RSSI of the transmission / reception antenna 101 and the reception-dedicated antenna 102 of the antenna set A from the RF system 204, and the reception-dedicated antenna 103 of the antenna set B. The same RSSI is input (step 302).

  Subsequently, the gain difference between antennas of the antenna set A and the gain difference between antennas of the antenna set B are obtained using the gain of each antenna obtained by measurement. Select antenna sets A and B by searching the matrix recorded in nonvolatile memory 210 using the gain difference between antennas of each antenna set and the correlation value associated with the terminal shape stored in RAM 209 as parameters. In this case, the diversity gain is estimated (step 303).

  The CPU 208 compares the diversity gains of the antenna sets A and B thus estimated (step 304), and determines an antenna set having a higher diversity gain as a combination of antennas to be selected (step 305).

2.3) Antenna Selection Control During Communication FIG. 4 is a flowchart showing antenna selection control during communication in the mobile communication terminal according to the present embodiment. Here, for example, it is assumed that the antenna set A, that is, the transmission / reception antenna 101 and the reception-dedicated antenna 102 are selected.

  First, the current detected shape of the terminal shape detecting unit 211 is stored in the RAM 209 (step 401). Subsequently, the CPU 208 inputs the received signal strength RSSI of the transmission / reception antenna 101 and the reception-dedicated antenna 102 of the currently selected antenna set A from the RF system 204 (step 402).

Subsequently, the CPU 208 uses, as parameters, the antenna-to-antenna gain difference of the antenna set A obtained from the gain of each antenna obtained by measurement, and the correlation value associated with the current terminal shape stored in the RAM 209 as parameters. By searching the matrix recorded in the nonvolatile memory 210, the diversity gain DA of the antenna set _A is estimated (step 403). CPU208 is diversity gain _{D A} of the estimated antenna set A, it is determined whether or not below a predetermined threshold value (step 404), if more than a predetermined threshold value (step 404: NO), the flow returns to step 401 . Thus, the inter-antenna gain difference and diversity gain of the currently selected antenna set A can always be monitored.

When diversity gain _{D A} of the estimated antenna sets A falls below a predetermined threshold value (step 404: YES), CPU 208 switches the antenna switch 205 at a high speed, the RSSI of each antenna of the antenna pair B from the RF system 204 type (step 405), estimates the diversity gain _{D B} when selecting an antenna set B (step 406). The diversity gain _{D B} of the estimated antenna sets B exceeds the diversity gain _{D A} of the antenna set A (step 407: YES), and if more than a predetermined threshold value (step 408: YES), CPU 208 is an antenna switch 205 And antenna set B, that is, transmitting / receiving antenna 101 and reception-only antenna 103 are selected (step 409).

  In the present embodiment, there are only two antenna sets A and B, but the present invention is not limited to this, and can be similarly applied when there are a plurality of antenna sets. In that case, steps 405 to 409 described above may be applied to each antenna set as a selection determination routine for other antenna sets. In addition, when switching antenna sets during continuous communication, there is a possibility that reception quality may be deteriorated.

  By executing a program corresponding to the flowcharts shown in FIGS. 3 and 4 on the CPU 208, the antenna selection control according to the present embodiment can be realized.

3. Other Embodiments FIG. 5 is a diagram showing the structure and antenna arrangement of a mobile communication terminal according to another embodiment of the present invention, where (A) is a side view in a closed state, and (B) is a plan view in a closed state. (C) is a side view of the open state. Members having the same functions as those in FIG. 1 are given the same reference numerals.

  The mobile communication terminal according to the present embodiment has a structure in which a first housing 10 and a second housing 11 are connected to each other by a hinge portion 12 so as to be rotatable in parallel planes. As in the embodiment shown in FIG. One transmitting / receiving antenna 101 and two reception-only antennas 102 and 103 are mounted at the same position. It is clear that the present invention can be applied to such a revolver type mobile communication terminal.

  Further, if the hinge portion 12 is rotatable in two axial directions, for example, the first housing 10 having the display portion is rotated in the horizontal direction with respect to the second housing 11 so that the display portion is exposed. It is also possible to close it. As described above, according to the present invention, an antenna set can be selected so as to obtain an optimal diversity gain even when the terminal is deformed in a shape of 4 or more.

  The present invention is applicable to a mobile communication terminal such as a mobile phone whose shape can be changed.

It is a figure which shows the structure and antenna arrangement | positioning of the portable communication terminal by one Example of this invention, (A) is a side view of a closed state, (B) is a top view of a closed state, (C) is an open state FIG. It is a block diagram which shows the function structure of the portable communication terminal by a present Example. It is a flowchart which shows the antenna selection control at the time of the communication channel setting in the portable communication terminal by a present Example. It is a flowchart which shows the antenna selection control during communication in the portable communication terminal by a present Example. It is a figure which shows the structure and antenna arrangement | positioning of the portable communication terminal by other Example of this invention, (A) is a side view of a closed state, (B) is a top view of a closed state, (C) is opened. It is a side view of a state.

Explanation of symbols

101 Transmitting and receiving antennas 102 and 103 Reception-only antenna 201 Duplexer 202 Filter 203 Amplifier 204 RF system 205 Antenna switch 206 Filter 207 Baseband processing unit 208 CPU
209 RAM
210 Nonvolatile Memory 211 Terminal Shape Detection Unit

Claims (10)

In a mobile communication terminal compatible with reception diversity that can change the relative positional relationship of at least three antennas,
Antenna selection means for selecting one antenna set from the at least three antennas;
Measuring means for measuring the gain difference between the antennas of the selected antenna set;
Control means for determining an antenna set to be used for reception diversity based on an inter-antenna distance determined according to the relative positional relationship and an inter-antenna gain difference of each antenna set, and for controlling the antenna selection means;
A portable communication terminal comprising:   The mobile communication terminal according to claim 1, wherein the control unit refers to a matrix in which the distance between the antennas, the gain difference between the antennas, and the reception diversity effect are associated with each other.   The at least three antennas include a first antenna for transmission and reception, and a second antenna and a third antenna dedicated to reception, and the antenna set is a set of first and second antennas or a set of first and third antennas. The mobile communication terminal according to claim 1, wherein the mobile communication terminal is any one of the above.   The mobile communication terminal according to any one of claims 1 to 3, wherein the first housing and the second housing having the at least three antennas are connected so as to rotate at least one axis. An antenna selection method in a reception diversity compatible mobile communication terminal capable of changing a relative positional relationship of at least three antennas,
Detecting the current relative position of the at least three antennas;
Measuring an inter-antenna gain difference of each antenna set of the at least three antennas;
Selecting an antenna set to be used for reception diversity based on the distance between antennas determined according to the relative positional relationship and the gain difference between the antennas;
An antenna selection method characterized by the above. An antenna selection method in a reception diversity compatible mobile communication terminal capable of changing a relative positional relationship of at least three antennas,
a) detecting the current relative position of the at least three antennas;
b) measuring the inter-antenna gain difference of the currently selected antenna set of the at least three antennas;
c) Estimating the receive diversity effect of the currently selected antenna set based on the inter-antenna distance determined according to the relative positional relationship and the inter-antenna gain difference;
d) When the receive diversity effect of the currently selected antenna set is lower than a predetermined threshold, select another antenna set and return to b) above.
e) If the receive diversity effect of the currently selected antenna set is greater than the receive diversity effect of other antenna sets and is equal to or greater than the predetermined threshold, the currently selected antenna set is used as the receive diversity. ,
An antenna selection method characterized by the above.   The antenna set used for the reception diversity is selected by referring to a matrix in which the distance between the antennas, the gain difference between the antennas, and the reception diversity effect are associated with each other. The antenna selection method described in 1.   The at least three antennas include a first antenna for transmission and reception and a second antenna and a third antenna dedicated to reception, and the antenna set is a set of the first and second antennas or a set of the first and third antennas. The antenna selection method according to claim 5, wherein the antenna selection method is any one of the following. A program for realizing an antenna selection function in a program control processor in a mobile communication terminal compatible with reception diversity capable of changing the relative positional relationship of at least three antennas,
A shape determining means detecting a current relative positional relationship of the at least three antennas;
Measuring means for measuring an inter-antenna gain difference of each antenna set of the at least three antennas;
Selecting an antenna set to be used for reception diversity based on an inter-antenna distance determined according to the relative positional relationship and the inter-antenna gain difference;
The program characterized by having. A program for realizing an antenna selection function in a program control processor in a mobile communication terminal compatible with reception diversity capable of changing the relative positional relationship of at least three antennas,
a) a shape determining means detecting a current relative positional relationship of the at least three antennas;
b) measuring means measuring an inter-antenna gain difference of the currently selected antenna set of the at least three antennas;
c) estimating a receive diversity effect of the currently selected antenna set based on an inter-antenna distance determined according to the relative positional relationship and the inter-antenna gain difference;
d) when the diversity diversity effect of the currently selected antenna set is lower than a predetermined threshold, select another antenna set and return to b);
e) If the receive diversity effect of the currently selected antenna set is greater than the receive diversity effect of other antenna sets and is equal to or greater than the predetermined threshold, the currently selected antenna set is used as the receive diversity. Steps,
A program characterized by that.

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