JP2004134951A - Radio communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication apparatus capable of selecting a base station capable of surely transmitting and receiving, in selecting a base station at the time of standby. <P>SOLUTION: The apparatus is provided with a communication control unit 20 for controlling communication with a radio base station, a present position detecting unit 23 for detecting a present position, a base station candidate storage unit 25 for storing data about a plurality of base station candidates, and a control unit 28 for controlling the units 20, 23 and 25. The unit 20 detects a base station with which can be communicated from among the base station candidates on the basis of the fact that the distance from the present position to the base station is within a predetermined distance and reception electric field strength, and stands by in the selected base station. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wireless communication device capable of detecting a current position, for example, to a mobile phone equipped with a GPS.
[0002]
[Prior art]
In a mobile phone system, which is one of the wireless communication devices, the output radio wave from the base station is set strong and the transmission output from the mobile phone is set weak. Then, at the time of standby, a base station having the strongest reception electric field strength (RSSI [Receive Signal Strength Indication]) is selected. The received electric field strength mainly depends on the distance from the base station to the mobile phone and the presence or absence of an obstacle therebetween. For example, when the distance from the base station to the mobile phone is long but there is no obstacle between them, and when the distance is short but there is a mountain between them, the former received electric field strength may be strong. In this case, a base station that is farther away is selected for standby.
[0003]
[Patent Document 1]
JP-A-2002-2416
[Problems to be solved by the invention]
Then, when making a call, communication is performed with the base station farther from the base station selected above, but the transmission output from the mobile phone is weak and may not reach the base station. Even in this case, there is a case where transmission is possible and communication is possible with a base station whose distance not selected at the time of standby is closer. For example, first because there is an obstacle such as a mountain between the base station and the terminal at a short distance from the terminal, the terminal does not select the closer base station, and then the terminal moves, This is a case where there is no obstacle between the base station closer to the terminal and the terminal, and communication between the terminal and the base station closer to the terminal is possible. Therefore, a different base station is selected at the time of waiting and at the time of calling, and a base station capable of transmitting at the time of re-calling must be searched again.
[0005]
The present invention has been made in view of the above problems, and has as its object to provide a wireless communication device capable of selecting a base station capable of reliably transmitting and receiving when selecting a base station in a standby state.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a communication control unit that controls communication with a radio base station, a current position detection unit that detects a current position, and a base station candidate storage that stores data on a plurality of base station candidates. Unit, the communication control unit, the current position detection unit, and a wireless communication device including a control unit that controls the base station candidate storage unit, the control unit, from the current position to the base station within a predetermined distance And detecting a communicable base station from the base station candidates based on the received electric field strength, and controlling the communication control unit to wait at the detected communicable base station. It is assumed that.
[0007]
As described above, by determining the base station to be awaited by using the data on the base station stored in the base station candidate storage unit, it is possible to wait at a base station at a distance where radio waves cannot reach at the time of transmission, although reception is possible. Is eliminated, and it is possible to reliably select a base station that can transmit and receive. Therefore, it is possible to provide a wireless communication device that can be used comfortably while avoiding a situation where connection is difficult at the time of calling.
[0008]
In the above wireless communication device, the base station capable of communication can be more reliably transmitted and received by detecting that the base station is within a predetermined distance from the current position and the received electric field strength.
[0009]
Further, in the above wireless communication device, the base station candidate storage section stores synchronization correction information corresponding to the base station candidate, and detects a communicable base station using the synchronization correction information. The determination time can be shortened. This is particularly effective when the distance from the wireless communication device to the base station is long.
[0010]
Further, in the above wireless communication device, when a response from the base station cannot be received at the time of calling, if the distance from the current position to the base station is within a predetermined distance, an automatic re-call is performed, and the current position to the base station is When the distance exceeds a predetermined distance, automatic re-calling may not be performed.
[0011]
As described above, when there is no response from the base station at the time of making a call, it is determined whether or not to repeat the call to the base station that has been waiting based on the distance to the base station. When the power exceeds the limit of the transmission output, that is, when it is not expected to be connected, it is possible to control so as not to make a call again, and to save power required at the time of calling and extend the battery life.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a wireless communication system. FIG. 1 shows a mobile phone 10 and base stations 11 and 12 as a part of a wireless communication system. There is no obstacle between the mobile phone 10 and the base station 11 at a distance X (for example, X = 20 km), and a mountain 13 at a distance Y (for example, Y = 10 km) between the mobile phone 10 and the base station 12. Suppose there is.
[0013]
FIG. 2 is a block diagram illustrating a configuration of the mobile phone 10. The mobile phone 10 detects a current position, a communication control unit 20 for controlling communication with a base station, an antenna 21 connected to the communication control unit 20 for wireless communication, a display unit 22 including a liquid crystal display or the like, and a current position. A current position detection unit 23 such as a GPS (Global Positioning System), an operation unit 24 operated by a user with a key, a base station candidate storage unit 25 for storing data on a plurality of base station candidates, and a current position etc. are temporarily stored. It has a RAM 26 for storing, a ROM 27 for storing programs necessary for the operation of the mobile phone 10, and a control unit 28 including a microcomputer for controlling the mobile phone 10 based on the programs and the like in the ROM 27. .
[0014]
Note that the base station candidate storage unit 25 stores position information (latitude / longitude) of each base station, a base station ID, and the like. For example, the data may be registered in advance with data of base stations nationwide at the time of manufacture, or the base station may be automatically registered by use of a user without registering data at the time of manufacture. Good.
[0015]
Next, the operation of the mobile phone 10 when selecting a base station during standby will be described. FIG. 3 is a flowchart illustrating the operation of the control unit 28 of the mobile phone 10. First, when the operation unit 24 is operated and the power of the mobile phone 10 is turned on, the current position detection unit 23 detects the current position in step S10.
[0016]
Next, the process proceeds to step S11 to calculate a distance from the calculated current position to each base station stored in the base station candidate storage unit 25. The distance is obtained from the latitude / longitude of the current position and the latitude / longitude of the base station stored in the base station candidate storage unit 25. Here, when a large number of base station candidates are stored in the base station candidate storage unit 25, it takes time to calculate all the base station candidates, and the control unit 28 is also burdened. Therefore, for example, a base station candidate having a latitude and longitude within a certain range centered on the current position may be selected, and the distance may be calculated only for the base station candidate. Further, for example, the range of latitude and longitude centering on the current position may be narrowed down until the number of base station candidates reaches a predetermined number (for example, five), and the distance may be calculated only for the base station candidate.
[0017]
Next, the process proceeds to step S12, and the measurement of the received electric field strength is started in ascending order of the distance calculated in step S11. Subsequently, the process proceeds to step S13, where it is determined whether or not the measured received electric field strength is equal to or more than a predetermined value. In step S13, it is determined that the base station having the received electric field strength less than the predetermined value cannot communicate, and the process returns to step S12 to measure the received electric field strength of the next shortest base station. On the other hand, if the received electric field strength is equal to or more than the predetermined value in step S13, the process proceeds to step S14 to wait at the base station.
[0018]
After step S11, the synchronization correction information may be read from the base station candidate storage unit 25 and used. Here, the synchronization correction information is information indicating a value of a phase difference corresponding to a distance between the base station 11 and the mobile phone 10. In order to synchronize a received radio wave with a clock inside the mobile phone 10, the PLL is shifted in advance. In this case, the reception radio wave is quickly pulled in, and the speed of the synchronization correction is increased. In particular, it is information on how much the PLL should be shifted from the center when the distance from the mobile phone 10 to the base station is long.
[0019]
When the synchronization correction information is used, for example, when the distance between the base station 11 and the mobile phone 10 is long, the mobile phone 10 receives a delayed radio wave. Therefore, the mobile phone 10 can synchronize with the delay of the received radio wave based on the synchronization correction information. With such a configuration, it is possible to quickly synchronize even when a radio wave delay occurs.
[0020]
For example, when the mobile phone 10 and the base stations 11 and 12 are arranged as shown in FIG. 1, the reception electric field strength of the base station 11 farther than the base station 12 closer due to the influence of the mountain 13 is smaller than that of the base station 12 closer to the base station 12. May be stronger. In this case, the conventional mobile phone selects the base station 11 having a strong received electric field strength as a standby base station. However, according to the present invention, the received electric field strength may be weak or more than a predetermined value, and the base station 12 having a short distance is selected as the standby base station. As a result, even if the mobile phone 10 has a transmission output with a limit distance of, for example, 15 km, it can transmit to the base station 12, so that it is possible to communicate by calling the same base station as the base station at the time of standby.
[0021]
As described above, by determining the base station to be awaited by using the data on the base station stored in the base station candidate storage unit 25, the base station at the distance where the radio wave can not be received at the time of transmission but the reception is possible is performed. Is eliminated, and a base station capable of transmitting and receiving can be reliably selected. Therefore, it is possible to provide a mobile phone that can be used comfortably while avoiding a situation where connection is difficult at the time of calling.
[0022]
Further, by waiting at the base station where the distance from the mobile phone 10 to the base station is within a predetermined distance and the reception electric field strength is equal to or more than a predetermined value, transmission and reception can be performed more reliably.
[0023]
If the mobile phone 10 is moved during standby, the base station may be selected again. For example, when the current position detection unit 23 detects that the mobile station has moved a certain distance, control may be performed so that the base station is selected again. At this time, if the detection of the current position is always performed, the processing load on the mobile phone 10 becomes large.
[0024]
Next, the operation of the mobile phone 10 when making a call from the standby state will be described. FIG. 4 is a flowchart showing the operation of the mobile phone 10 when making a call. When the operation unit 24 is operated in step S20 during standby after the process of FIG. 3 and a call is made to the standby base station, the process proceeds to step S21 to determine whether or not there is a response from the base station. If there is a response from the base station in step S21, normal processing is performed and communication is started. If there is no response from the base station in step S21, the process proceeds to step S22 to determine whether the distance from the mobile phone 10 to the base station is within a predetermined distance.
[0025]
If it is within the predetermined distance in step S22, it is determined that there is a base station within a communicable distance, and the process proceeds to step S23 to call again. On the other hand, if the distance exceeds the predetermined distance in step S22, it is determined that the distance is incapable of communication, and the process is terminated without calling again. Note that if there is no response even after the re-call, a setting may be made to repeat the re-call several times, or a different base station may be selected to re-call.
[0026]
Note that the re-calling from step S20 to step S23 is performed at predetermined time intervals. For example, in the above-described step S20, timing is started by a timing circuit (not shown) mounted in the mobile phone 10, When the clock circuit measures a predetermined time, a re-call may be started in step S23.
[0027]
Further, a call may be re-issued every time the user moves a predetermined distance.
[0028]
As described above, when there is no response from the base station at the time of calling, whether or not to repeat the call to the waiting base station is determined based on the distance to the base station. Can be controlled so as not to recall when the transmission power exceeds the limit of the transmission output, that is, when there is no possibility of connection. As a result, the power required at the time of calling can be saved and the battery can last longer.
[0029]
Note that the wireless communication device of the present invention is not limited to a mobile phone, but may be applied to any wireless communication device that selects and communicates with a certain base station from a plurality of base stations. At this time, the wireless communication device only needs to include at least the communication control unit 20, the current position detection unit 23, the base station candidate storage unit 25, and the control unit 28, and the display unit 22, the operation unit 24, etc. It can be configured to be connected to a terminal provided in the device.
[0030]
【The invention's effect】
According to the wireless communication device of the present invention, a communication control unit that controls communication with a wireless base station, a current position detection unit that detects a current position, and a base station candidate storage unit that stores data on a plurality of base station candidates And a control unit for controlling a communication control unit, a current position detection unit, and a base station candidate storage unit, wherein the control unit detects a communicable base station from the base station candidates, and detects the detected communicable base station. By controlling the communication control unit to wait at a suitable base station, reception is possible but the base station at a distance where radio waves do not reach at the time of transmission is eliminated, and a base station capable of reliably transmitting and receiving is selected. be able to. Therefore, it is possible to provide a wireless communication device that can be used comfortably while avoiding a situation where connection is difficult at the time of calling.
[0031]
Further, according to the present invention, the communicable base station can be more reliably transmitted and received by detecting that the base station is within a predetermined distance from the current position and based on the received electric field strength.
[0032]
Further, according to the present invention, the synchronization correction information is stored in the base station candidate storage unit in correspondence with the base station candidate, and the base station capable of communication is detected using the synchronization correction information, whereby the speed of the synchronization correction is increased. Can be realized. This is particularly effective when the distance from the wireless communication device to the base station is long.
[0033]
Further, according to the present invention, when a response from the base station cannot be received at the time of calling, if the distance from the current position to the base station is within a predetermined distance, an automatic re-call is performed, and a predetermined distance from the current position to the base station is determined. By preventing the automatic re-calling when the distance is exceeded, it is possible to control so that the re-calling is not performed when the distance to the base station exceeds the limit of the transmission output, that is, when there is no possibility of connection. As a result, the power required at the time of calling can be saved and the battery can last longer.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a wireless communication system according to the present invention.
FIG. 2 is a block diagram illustrating a configuration of a mobile phone according to the present invention.
FIG. 3 is a flowchart showing an operation of the mobile phone when a base station is selected according to the present invention.
FIG. 4 is a flowchart showing the operation of the mobile phone at the time of calling according to the present invention.
[Explanation of symbols]
10 Mobile phone (wireless communication device)
11 base station 12 base station 13 mountain 20 communication control unit 21 antenna 22 display unit 23 current position detection unit 24 operation unit 25 base station candidate storage unit 26 RAM
27 ROM
28 Control unit

Claims (3)

A communication control unit that controls communication with the radio base station, a current position detection unit that detects a current position, a base station candidate storage unit that stores data on a plurality of base station candidates, the communication control unit, the current position In a wireless communication device including a detection unit and a control unit that controls the base station candidate storage unit,
The control unit detects a communicable base station from among the base station candidates based on a fact that a distance from the current position to the base station is within a predetermined distance and a received electric field strength, and detects the detected communicable base station. A wireless communication device for controlling the communication control unit so as to wait for the wireless communication. 2. The wireless communication apparatus according to claim 1, wherein synchronization correction information is stored in the base station candidate storage unit in correspondence with the base station candidate, and a communicable base station is detected using the synchronization correction information. . If a response from the base station cannot be received at the time of calling,
When the distance from the current position to the base station is within a predetermined distance, an automatic recall is performed,
3. The wireless communication apparatus according to claim 1, wherein when the distance from a current position to the base station exceeds a predetermined distance, automatic re-calling is not performed.

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