JP2002026800A - Mobile communication terminal and mobile communication system - Google Patents

Abstract

(57) [Summary] [Problem] There is a problem that mutual interference of radio waves occurs between a plurality of mobile stations. SOLUTION: A GPS antenna 2 for receiving a GPS signal.
And a GPS receiver 3, a car navigation system 4 for storing base station position information and calculating mobile station position information from GPS signals, and a radio wave for receiving radio waves from the base station and transmitting directionally to the base station. The directional antenna 5 and the transmitting / receiving unit 6 for adjusting the beam direction, and when receiving a radio wave from the base station, calculates the received electric field intensity information, and based on the received electric field intensity information, the base station position information, and the mobile station position information. An information processing unit 7 and a control unit 8 for controlling the beam direction are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication terminal provided in a mobile station that performs mobile communication with a base station via radio waves, and a mobile communication system that hands off a base station to be connected.

[0002]

2. Description of the Related Art In a mobile communication system, each base station has a small communicable area called a cell, and a wide communicable area is established by cells of base stations installed at a plurality of different points. I try to cover. In this way, a frequency can be assigned to each cell, and a communication band can be used effectively.

In such a mobile communication system, a mobile station that has originated a call connects to a base station that has most strongly received radio waves of a call transmitted in a non-directional manner. Then, the power of the radio wave to be transmitted is controlled in accordance with the movement, and the handoff (hand-off, connection destination switching operation) of the base station is performed in order to maintain the communication quality when the radio wave is separated to a certain distance from the base station. Conventionally, the necessity of handoff is determined by comparing the received electric field strength of a radio wave from a base station with a threshold value.

[0004] In this system, even in the case of a mobile station moving in a direction away from a base station that has most strongly received a call wave, connection with the base station often occurs. In addition, since radio waves are affected by a propagation path such as shadowing, inappropriate handoff is repeatedly performed according to fluctuations in the received electric field strength.

For this purpose, Japanese Patent Application Laid-Open No. Hei 9-121378 discloses that a directional antenna is provided in a base station, and the beam direction of the directional antenna is adjusted so that the reception electric field strength of the non-directional radio wave from the mobile station is maximized. Is controlled to specify the position of the mobile station and perform handoff. Also, Japanese Patent Application Laid-Open
In Japanese Patent Application Laid-Open No. 1-69411, in order to suppress the influence of a propagation path such as shadowing, a handoff is performed by referring to positional information of a mobile station while moving using a GPS signal.

[0006]

Since the conventional mobile communication terminals and mobile communication systems are configured as described above, there has been a problem that mutual interference of radio waves occurs between a plurality of mobile stations.

In order to avoid mutual interference, communication must be performed while changing the frequency for each mobile station, which limits the communication capacity.

[0008] These problems have not been solved in either JP-A-9-121378 or JP-A-11-69411.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a mobile communication terminal capable of effectively using a communication band by suppressing mutual interference between mobile stations. Aim.

Another object of the present invention is to configure a mobile communication system capable of performing more appropriate handoff.

[0011]

A mobile communication terminal according to the present invention comprises: a GPS signal receiving means for receiving a GPS signal;
Position information calculating means for storing base station position information and calculating mobile station position information from a GPS signal, and transmitting and receiving means for receiving a radio wave from the base station and adjusting a beam direction of a radio wave to be directionally transmitted to the base station. And beam control means for controlling the beam direction based on the received electric field strength information, the base station position information and the mobile station position information, while calculating the received electric field strength information when the transmitting / receiving means receives a radio wave from the base station. It is prepared for.

In the mobile communication terminal according to the present invention, the beam control means determines the transmission electric field intensity of the radio wave based on the reception electric field intensity information, the base station position information and the mobile station position information, and transmits the radio wave to be directionally transmitted. The transmission / reception means controls the electric field strength.

[0013] In the mobile communication terminal according to the present invention, the position information calculating means stores base station position information in advance.

[0014] In the mobile communication terminal according to the present invention, the position information calculating means stores base station position information via radio waves received by the transmitting / receiving means from the base station.

In the mobile communication terminal according to the present invention, the transmitting and receiving means has the first beam and the second beam, respectively.
The first beam and the second beam are independently controlled by beam control means.

[0016] The mobile communication system according to the present invention comprises:
And the second base station receive the GPS signal, respectively, and transmit the beam whose beam direction is controlled based on the mobile station position information, the base station position information, and the received electric field strength information to the first base station and the second base station. And the mobile station includes the mobile communication terminal according to claim 5.
Controlling a first beam with a second base station, controlling a second beam with a second base station, and performing handoff to the second base station with the second beam. It is.

In the mobile communication system according to the present invention, the mobile station determines a handoff based on the received field strength information, the base station position information, and the mobile station position information.

In the mobile communication system according to the present invention, the first base station and the second base station respectively control the transmission field strength based on the reception field strength information, the base station location information and the mobile station location information. It was made.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a diagram showing a configuration of a circuit block of a mobile communication terminal according to Embodiment 1 of the present invention. Figure 1
In the above, 1 is a GPS (Global Position)
(Ning System) signal, which is transmitted from a plurality of satellites (not shown). 2 is a G that receives the GPS signal 1
A PS antenna (GPS signal receiving means) 3 is a GPS receiving unit (GPS signal receiving means) that processes the GPS signal 1 received by the GPS antenna 2.

Reference numeral 4 denotes a car navigation system (position information calculating means), which calculates mobile station position information indicating the position of the mobile station from the GPS signal 1 processed by the GPS receiving unit 3 and calculates the position of the base station. Is also stored in advance.

Reference numeral 5 denotes a directional antenna for transmission / reception (transmitting / receiving means), which receives a radio wave from a base station (not shown) and directionally transmits a radio wave to the base station. Reference numeral 6 denotes a transmission / reception unit (transmission / reception means) which processes a radio wave from the base station received by the directional antenna 5 and controls the beam direction and transmission electric field strength of the radio wave to be directionally transmitted.

Reference numeral 7 denotes an information processing unit (beam control means). When receiving the radio wave from the base station via the transmission / reception unit 6, the information processing unit 7 calculates the received electric field intensity information indicating the intensity of the received radio wave, and also transmits the mobile station position information and the base station information from the car navigation system 4. The station position information is received, and the optimum values of the transmission field intensity and the beam direction are calculated based on the mobile station position information, the base station position information, and the reception field intensity information.

Reference numeral 8 denotes a control unit (beam control means). When receiving the optimum values of the transmission electric field intensity and the beam direction calculated by the information processing unit 7, the control unit 8 changes the transmission electric field intensity and the beam direction of the radio wave directionally transmitted from the directional antenna 5 via the transmission / reception unit 6. Control. In FIG. 1, components related to other communication functions are omitted.

Next, the operation will be described. A GPS signal 1 is transmitted from a satellite (not shown) for each clock.
The PS receiver 3 receives the G signal received by the GPS antenna 2
The PS signal 1 is processed and output to the car navigation system 4. The car navigation system 4 calculates time-varying mobile station position information based on the GPS signal 1.

When the directional antenna 5 receives the radio wave from the base station, the information processing unit 7 calculates the received electric field strength information of the radio wave via the transmission / reception unit 6. The information processing unit 7 knows the positional relationship with the base station from the mobile station position information and the base station position information of the car navigation system 4, and also refers to the received electric field intensity information to determine the beam direction of the directional antenna 5 and the transmission electric field. Calculate the optimum value of the strength. The control unit 8 which has received the optimum values of the beam direction and the transmission electric field strength from the information processing unit 7 transmits the directional antenna 5 via the transmission / reception unit 6.
The beam direction and the transmission electric field strength of the radio wave to be directionally transmitted from are controlled.

As described above, based on the mobile station position information, the base station position information, and the received electric field strength information, the beam direction of the radio wave to be directionally transmitted and the transmission electric field are set so that the mobile station can optimally communicate with the base station. Since the strength is determined, mutual interference with other mobile stations can be suppressed,
The transmission electric field strength can be optimized.

As described above, according to the first embodiment, GPS antenna 2 and GPS antenna 2 for receiving GPS signal 1
While storing the PS receiving unit 3 and the base station position information,
A car navigation system 4 that calculates mobile station position information using a GPS signal 1, receives radio waves from a base station, and controls the beam direction and transmission electric field strength of radio waves to be directionally transmitted to the base station. The directional antenna 5 and the transmitting / receiving unit 6 receive the radio wave from the base station to calculate the received electric field strength information, and calculate the beam direction and the transmitted electric field strength from the base station position information, the mobile station position information and the received electric field strength information. The information processing unit 7 for calculating the optimum value, and the control for controlling the beam direction and the transmission electric field intensity of the radio wave transmitted directionally from the directional antenna 5 by the transmission and reception unit 6 when receiving the optimum values of the beam direction and the transmission electric field intensity. Since it is provided with the unit 8, the beam direction and the transmission electric field strength are controlled so that the optimum communication can be performed.
The effect is obtained that the mutual interference between the mobile stations can be suppressed and the communication band can be used effectively, and the effect that the power consumption can be saved.

Further, according to the first embodiment, the base station position information is stored in advance in the car navigation system 4, so that the position of the base station can be easily obtained.

Note that the car navigation system 4 may directly obtain necessary base station position information through communication with the base station. By doing so, the storage capacity of the car navigation system 4 can be reduced.

Further, the position information calculating means is not limited to the car navigation system 4, but may be any as long as it can store the base station position information and can calculate the mobile station position information using the GPS signal 1. .

Further, the number of beams of radio waves directionally transmitted from directional antenna 5 is not particularly limited.
May have two beams as shown by.

Embodiment 2 FIG. FIG. 2 is a diagram illustrating an operation of the mobile communication system according to the second embodiment of the present invention. In FIG. 2, reference numerals 11 and 12 denote base stations (first
Base station, the second base station), and has a GPS signal reception analysis function and a directional radio wave control function. Base station 1
Each of the mobile stations 1 and 12 can obtain the position information of the mobile station by the GPS signal reception analysis function, and can transmit the radio waves of the beams 11A and 12A directionally by the directional radio wave control function.

Reference numeral 13 denotes a mobile station, which includes the mobile communication terminal described in the first embodiment and has two beams 13A, 1A.
3B (first beam, second beam). 1
Reference numeral 4 denotes a satellite, and a GPS signal 14 transmitted by the satellite 14
A, 14B and 14C are being received by base stations 11, 12 and mobile station 13. Actually, there are a plurality of satellites 14, but they are not shown in FIG.

Next, the operation will be described. The mobile station 13 moving from the cell of the base station 11 to the cell of the base station 12 receives the base station 1 via the beam 11A and one of the beams 13A.
1 is connected. The mobile station 13 receives the GPS signal 14C and can grasp the mutual positional relationship with the base stations 11 and 12, so that the base station 11, which is communicating the beam directions of the beams 13A and 13B, and the handoff candidate , Respectively.

The base stations 11 and 12 transmit the GPS signals 14
A and 14B are received, and the mutual positional relationship with the mobile station 13 can be confirmed. Therefore, the base stations 11 and 12 transmit the beam 11 based on the positional relationship with the mobile station 13 and the received electric field strength of the radio wave from the mobile station 13.
The beam azimuth of A and 12A and the transmission electric field strength can be optimized. As described above, the base stations 11, 12 and the mobile station 13 receive the GPS signals 14A to 14C and control the beam directions and the transmission electric field strengths of the individual beams 11A, 12A, 13A, 13B.

When the mobile station 13 moves from the cell of the base station 11 to the cell of the base station 12 to some extent, handoff from the base station 11 to the base station 12 is performed. In the second embodiment, the timing at which handoff is performed is determined from the received electric field strengths from the base stations 11 and 12 and the mutual positional relationship between the base stations 11 and 12 and the mobile station 13.

That is, thresholds for the distance between the base station position information and the mobile station position information and the reception electric field strength information are respectively determined, and handoff is performed when the thresholds are exceeded. By determining the handoff by the two determination factors in this way, it becomes possible to perform a more optimal handoff as compared with the related art.

When handoff from the base station 11 to the base station 12 is performed, the mobile station 13 communicates with the base station 12 by the beam 13B. In addition to the beam 13A controlled with the current connection base station 11, the beam 1 controlled with the connection destination base station 12 after handoff
Since the mobile station 13 has 3B, the handoff can be performed more appropriately and easily.

As described above, according to the second embodiment, the GPS signal reception analysis function for receiving the GPS signals 14A and 14B from the satellite 14 and grasping the mobile station position information of the mobile station 13 and the beam 11A, Base stations 11 and 12 each having a directional radio control function capable of controlling 12A
And the mobile station 13 having the mobile communication terminal of the first embodiment and controlling the two beams 13A and 13B, controlling the beam 13A with the base station 11, and controlling the beam 13A with the base station 12. Since the beam 13B is controlled to perform handoff according to the mutual positional relationship and the received electric field strength obtained from the GPS signal 14C, mutual interference with other mobile stations can be suppressed and the communication band can be used effectively. At the same time, an effect is obtained that a more optimal handoff can be performed as compared with the related art.

Embodiment 3 In the third embodiment, transmission power control after handoff shown in the second embodiment will be described. FIG. 3 is a diagram illustrating an operation of the mobile communication system according to the third embodiment of the present invention. In FIG. 3, FIG.
The same reference numerals are given as.

The mobile station 13 which has been handed off from the base station 11 to the base station 12 by the handoff communicates with the beam 12A of the base station 12 using the beam 13B.
At this time, the distance between the base station 12 and the mobile station 13 changes every moment according to the movement of the mobile station 13, and therefore, depending on the mutual positional relationship and the received electric field strength, the base station 12,.
The mobile station 13 controls the transmission electric field strength of the beams 12A and 13B, respectively. By doing this,
The transmission electric field strength is controlled so that optimal communication can be performed, and the effect that power consumption can be saved can be obtained.

[0042]

As described above, according to the present invention, the GP
GPS signal receiving means for receiving the S signal, position information calculating means for storing the base station position information and calculating the mobile station position information from the GPS signal, receiving radio waves from the base station, and providing directivity to the base station. Transmitting and receiving means for adjusting the beam direction of the transmitted radio wave, and when the transmitting and receiving means receives the radio wave from the base station, calculates the received electric field strength information,
Beam control means for controlling the beam direction based on the received electric field strength information, the base station position information and the mobile station position information, so that the beam direction is controlled so that optimum communication can be performed; An effect is obtained that the mutual interference between the signals can be suppressed and the communication band can be used effectively.

According to the present invention, the beam control means determines the transmission electric field intensity of the radio wave based on the reception electric field intensity information, the base station position information and the mobile station position information, and converts the radio wave to be transmitted directionally into the transmission electric field intensity. Since the transmission / reception means is controlled, the transmission electric field strength is controlled so that optimum communication can be performed, and an effect that power consumption can be saved can be obtained.

According to the present invention, the position information calculating means stores the base station position information in advance, so that the position of the base station can be easily obtained.

According to the present invention, since the position information calculating means stores the base station position information via the radio wave received by the transmitting / receiving means from the base station, the storage capacity of the position information calculating means can be reduced. The effect that it can be obtained is obtained.

According to the present invention, the transmitting and receiving means has the first beam and the second beam, respectively, and the beam control means independently controls the first beam and the second beam. The effect that handoff can be easily performed is obtained.

According to the present invention, the first base station and the second base station each receive a GPS signal, and the beam direction is controlled based on the mobile station position information, the base station position information, and the received field strength information. The first base station and the second base station each include a beam, and the mobile station includes the mobile communication terminal according to claim 5, and controls the first beam with the first base station; Since the second beam is controlled between the second base station and the handoff to the second base station is performed by the second beam, the communication band is suppressed while suppressing the mutual interference with another mobile station. Can be effectively used.

According to the present invention, the mobile station determines the handoff based on the received electric field strength information, the base station position information, and the mobile station position information, so that a more optimal handoff is performed as compared with the related art. The effect that it can be obtained is obtained.

According to the present invention, the first base station and the second base station respectively control the transmission field strength based on the reception field strength information, the base station location information and the mobile station location information. In addition, it is possible to control the transmission electric field strength so as to perform optimal communication, and to save power consumption.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a circuit block of a mobile communication terminal according to Embodiment 1 of the present invention.

FIG. 2 is a diagram illustrating an operation of a mobile communication system according to a second embodiment of the present invention.

FIG. 3 is a diagram illustrating an operation of a mobile communication system according to a third embodiment of the present invention.

[Explanation of symbols]

1, 14A, 14B, 14C GPS signal, 2 GPS
Antenna (GPS signal receiving unit), 3 GPS receiving unit (GPS signal receiving unit), 4 car navigation system (position information calculating unit), 5 directional antenna (transmitting / receiving unit), 6 transmitting / receiving unit (transmitting / receiving unit), 7 information processing (Beam control means), 8 control sections (beam control means), 11 base stations (first base station), 12 base stations (second base station), 11A and 12A beams, 13 mobile stations, 13A beams ( 1st beam), 13B beam (second beam), 14 satellites.

Claims (8)

[Claims] 1. A mobile communication terminal provided in a mobile station that communicates with a base station via radio waves, a GPS signal receiving means for receiving a GPS signal, storing base station position information and moving from the GPS signal. Position information calculating means for calculating station position information; transmitting and receiving means for receiving a radio wave from the base station and controlling a beam direction of a radio wave to be directionally transmitted to the base station; and Receiving the received electric field strength information, and further comprising a beam control means for controlling the beam direction based on the received electric field strength information, the base station position information and the mobile station position information. Mobile communication terminal. 2. The beam control means includes: reception electric field strength information;
2. The mobile station according to claim 1, wherein the transmission electric field intensity of the radio wave is determined based on the base station position information and the mobile station position information, and the transmission / reception means controls the radio wave to be directionally transmitted to the transmission electric field intensity. Communication terminal. 3. The mobile communication terminal according to claim 1, wherein the position information calculating means stores base station position information in advance. 4. The mobile communication terminal according to claim 1, wherein the position information calculating means stores the base station position information via a radio wave received by the transmitting / receiving means from the base station. 5. The transmitting / receiving means comprises a first beam and a second beam.
The beam control means controls the first beam and the second beam independently of each other, wherein the beam control means independently controls the first beam and the second beam. Mobile communication terminal. 6. A first base station connected to a mobile station via a radio wave, a second base station, the first base station, and the second base station.
Move through the communicable area formed from the base station of
In a mobile communication system including a mobile station that performs handoff from the first base station to the second base station, the first base station and the second base station each receive a GPS signal, and A beam whose beam direction is controlled based on station position information, base station position information, and received electric field strength information, respectively, wherein the mobile station includes the mobile communication terminal according to claim 5 and the first base station. Controlling a first beam between the second base station and the second base station, and performing handoff to the second base station by the second beam. Mobile communication system. 7. The mobile communication system according to claim 6, wherein the mobile station determines a handoff based on the received field strength information, the base station position information, and the mobile station position information. 8. The method according to claim 1, wherein the first base station and the second base station control the transmission field strength based on the reception field strength information, the base station location information and the mobile station location information, respectively. The mobile communication system according to claim 6 or 7.