JP2004228881A - Mobile communication system, movement prediction device and changeover control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication system for accurately predicting the moving route of a mobile communication terminal and performing accurate handover by referring to map information. <P>SOLUTION: The mobile communication system is constituted of radio base stations 20A-20C connected with the mobile communication terminal 10 through a radio communication channel and a movement prediction device 30 for predicting the moving route of the mobile communication terminal, and the mobile communication terminal switches the radio base station to be a connecting party and performs communication. The mobile communication terminal is provided with a position information detection means for detecting the position of the mobile communication terminal. The movement prediction device is connected with a map information storage part 40 storing the map information, predicts the moving route of the mobile communication terminal on the basis of position information detected by the position information detection means and the map information acquired from the map information storage part, predicts the radio base station to be the connecting party of the mobile communication terminal next and controls the changeover of the radio base station to be the connecting party of the mobile communication terminal. <P>COPYRIGHT: (C)2004,JPO&amp;NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mobile communication terminal, and more particularly, to a mobile communication system capable of performing handover efficiently, a mobile communication terminal used therefor, and a handover control method.
[0002]
[Prior art]
In a mobile communication system, a base station is installed such that cells (service areas communicable from a base station) are adjacent to each other, and a mobile communication terminal sets a wireless communication line with any of the base stations, Perform communication. Then, when the mobile communication terminal moves, a base station to be a communication partner is selected, a wireless communication line is re-established with the base station constituting the cell to which the mobile communication terminal belongs, and the mobile communication terminal moves. However, communication can be performed without interruption. The process of selecting the base station and switching the wireless communication line is called handover.
[0003]
In order to select a base station suitable for the handover, position detecting means for detecting the current position of the mobile communication device, a machine-readable recording medium storing map information including identification information and position information of the base station, and Search means for searching the recording medium for identification information and position information of the peripheral base station, taking into account the current position and the positional information of the peripheral base station in addition to the radio wave intensity of each peripheral base station. A mobile communication device that performs position registration and a traveling direction detection unit are provided, and in addition to the radio wave intensity of the surrounding base station, the current position information and the traveling direction are reported to the base station in the middle of communication, and the base station side There has been proposed a mobile communication apparatus that enables handover to a handover destination base station determined based on a report so that the best base station can be determined.
[0004]
[Patent Document 1]
JP-A-2001-69548 [0005]
[Problems to be solved by the invention]
However, in the above-described conventional communication device, the traveling direction is obtained from the current position of the moving object obtained by the GPS, and the moving path of the moving object is predicted based on the assumption that the moving object moves linearly at a constant speed. Therefore, when the route on which the moving object travels is curved, the moving route of the moving object cannot be accurately predicted. Therefore, it was not possible to select an optimal base station for communication, and there were problems such as frequent handovers, poor communication quality, poor communication quality, and disconnection of communication.
[0006]
An object of the present invention is to provide a mobile communication system that accurately predicts a moving route of a mobile communication terminal by referring to map information and performs an accurate handover.
[0007]
[Means for Solving the Problems]
The first invention comprises a mobile communication terminal, a radio base station connected to the mobile communication terminal via a radio communication line, and a movement prediction device for predicting a movement route of the mobile communication terminal, In a mobile communication system in which a mobile communication terminal performs communication by switching a wireless base station to be a connection partner, the mobile communication terminal includes position information detecting means for detecting a position of the mobile communication terminal, and the movement prediction device includes: Connected to a map information storage unit that stores information, and based on the position information detected by the position information detection unit and the map information acquired from the map information storage unit, determines a travel route of the mobile communication terminal. Predicting, based on the movement route prediction result, the next wireless base station to be connected to the mobile communication terminal, and disconnecting the wireless base station to be connected to the mobile communication terminal. To control the example.
[0008]
According to a second invention, in the first invention, the movement prediction device notifies the wireless base station to which the mobile communication terminal is to connect next, of the identification information of the mobile communication terminal. .
[0009]
In a third aspect based on the first or second aspect, when the wireless base station receives the notification of the identification information of the mobile communication terminal that switches a connection partner to the wireless base station, the wireless base station uses a channel used by the mobile communication terminal. Is reserved.
[0010]
In a fourth aspect based on the first to third aspects, the position information detecting means is a GPS receiver.
[0011]
A mobile communication terminal according to a fifth aspect is used for the mobile communication system according to the first to fourth aspects.
[0012]
A sixth invention is a mobile communication terminal having position information detecting means for detecting a position of the mobile communication terminal, a wireless base station connected to the mobile communication terminal via a wireless communication line, and a mobile communication terminal. The mobile communication terminal includes a movement prediction device that predicts a route, and a map information storage unit that is connected to the movement prediction device and stores map information. The mobile communication terminal performs communication by switching a wireless base station as a connection partner. In the movement prediction device used in the mobile communication system, based on the position information detected by the position information detecting means and the map information obtained from the map information storage unit, predicts the movement route of the mobile communication terminal, Based on the prediction result of the movement route, a wireless base station to be connected to the mobile communication terminal is predicted next, and the wireless base station to be connected to the mobile communication terminal is disconnected. To control the example.
[0013]
In a seventh aspect based on the sixth aspect, the identification information of the mobile communication terminal is used to reserve a channel used by the mobile communication terminal with respect to the next wireless base station to be connected to the mobile communication terminal. Is notified.
[0014]
In an eighth aspect based on the sixth or seventh aspect, the difference between the first position detected by the position information detecting means and the second position detected a predetermined time after the detection of the first position is determined. A speed calculating unit configured to calculate a moving speed of the mobile communication terminal based on the comparison result, and based on the information on the moving speed and a result of the prediction of the moving route, a wireless communication target to be next connected to the mobile communication terminal; The method is characterized in that a base station is predicted and switching of a wireless base station as a connection partner of the mobile communication terminal is controlled.
[0015]
A ninth invention is a mobile communication terminal having position information detecting means for detecting the position of a mobile communication terminal, a wireless base station connected to the mobile communication terminal via a wireless communication line, and a mobile communication terminal. The mobile communication terminal includes a movement prediction device that predicts a route, and a map information storage unit that is connected to the movement prediction device and stores map information. The mobile communication terminal performs communication by switching a wireless base station as a connection partner. A switching control method of a radio base station used in a mobile communication system, comprising detecting a position of the mobile communication terminal, and based on position information of the mobile communication terminal and map information acquired from the map information storage unit. Predicting the movement route of the mobile communication terminal, and predicting the next wireless base station to be connected to the mobile communication terminal based on the prediction result of the movement route, and determining the connection phase of the mobile communication terminal. It controls the switching of the radio base station as a.
[0016]
In a tenth aspect based on the ninth aspect, the mobile base station notifies the identification information of the mobile communication terminal to a wireless base station to which the mobile communication terminal is to be connected next. Is reserved for a channel to be used.
[0017]
In an eleventh aspect based on the ninth or tenth aspect, the first position detected by the position information detecting means and the second position detected a predetermined time after the detection of the first position are determined. Based on the comparison result, the moving speed of the mobile communication terminal is calculated, and based on the calculated moving speed information and the prediction result of the moving route, the next wireless base station to be connected to the mobile communication terminal is determined. It is characterized by predicting and controlling the switching of the wireless base station to be connected to the mobile communication terminal.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0019]
FIG. 1 is a block diagram showing a configuration of a typical mobile phone as mobile communication terminal 10 of the present embodiment.
[0020]
The antenna 1 is connected to the transmission / reception unit 2, receives radio waves from the radio base station, and transmits radio waves to the radio base station. The transmission / reception unit 2 includes a transmission unit and a reception unit. The transmission unit generates a high-frequency signal to be transmitted from the antenna 1, and the reception unit amplifies the high-frequency signal received by the antenna 1, performs frequency conversion, and performs baseband signal transmission. Is output to the RF control unit 3.
[0021]
The RF control unit 3 includes a baseband unit and a wireless control unit. The baseband unit demodulates the baseband signal into a voice signal by using a codec unit in the baseband unit. The codec modulates the audio signal to generate a baseband signal. Further, the wireless control unit controls the frequency transmitted and received by the transmitting and receiving unit 2, the transmission and reception timing, and the output of the radio wave to be transmitted.
[0022]
The control unit 4 is mainly configured by a CPU, and based on data stored in a memory (RAM and ROM) 5, a portable unit such as the transmission / reception unit 2, the GPS unit 6, the operation unit 7, the display unit 8, and the like. Control each part of the telephone. The GPS unit 6 receives radio waves from GPS satellites, measures the position (latitude, longitude) of the own device, and acquires position information. The operation unit 7 receives input of characters and numbers, and an operation instruction to the mobile phone. The display unit 8 is controlled by the control unit 4 and displays a character information, image information, an operation state of the mobile phone (radio field intensity, remaining battery power, time) and the like, and a backlight for illuminating the liquid crystal display panel. It is constituted by and.
[0023]
Further, the mobile phone has a transmitting section (not shown) for converting an acoustic signal into an electric signal, and a receiving section (not shown) for converting an electric signal into an acoustic signal.
[0024]
FIG. 2 is a configuration diagram of the mobile communication system according to the embodiment of the present invention.
[0025]
The mobile communication terminal 10 receives pilot signals from a plurality of base stations 20A to 20C and transmits a reception status (C / I value) to the base stations. On the base station side, based on the reception state of the signal from the base station transmitted from the mobile communication terminal, the most suitable base station for connection with the mobile communication terminal 10 is selected, and the base station and the mobile communication terminal are selected. A wireless communication line is set between the base station and the base station and the mobile communication terminal to perform wireless communication.
[0026]
The movement prediction device 30 is connected to the base stations 20A to 20C, acquires position data of the mobile communication terminal 10, and calculates a moving speed and a moving direction of the mobile communication terminal 10 from a change in the position. Further, the travel route of the mobile communication terminal 10 is predicted with reference to the map information database 40.
[0027]
The map information database 40 is connected to the movement prediction device 30, and stores map information (arterial roads and railway lines that can be a moving route of the mobile communication terminal 10) and cell information of the base station (the base station) associated with the map information. Information on service areas communicable from stations and handover points on moving routes) are stored. The map information database 40 may be provided outside the movement prediction device 30 or may be provided inside the movement prediction device 30 to constitute an integrated control device.
[0028]
Next, the operation of the mobile communication system according to the embodiment of the present invention will be described with reference to FIG. 2 and FIG.
[0029]
The mobile communication terminal 10 is communicating with the base station 20A. Also, the mobile communication terminal 10 receives the position information of the mobile communication terminal 10 obtained by receiving radio waves from the GPS satellites, together with the measurement time information of the position, via the base station 20A that is currently communicating with the mobile prediction device 30. Send to The movement prediction device 30 specifies the time interval of position measurement from the received time information, specifies the movement distance of the time from the position information, and calculates the movement speed. Further, the moving direction is calculated based on the difference between the position information of the mobile communication terminals 10. Note that the mobile communication terminal 10 may be configured to calculate the moving speed and the moving direction of the own terminal from the position information of the own terminal and transmit the moving speed and the moving direction to the movement prediction device 30.
[0030]
Then, the movement prediction device 30 refers to the map information stored in the map information database 40 that can be a route along which the terminal such as a road or a track moves at the place, and predicts the movement of the mobile communication terminal 10. I do. For example, as shown in FIG. 3, if the current position of the mobile communication terminal 10 is at point G on the road A and the moving direction of the mobile communication terminal 10 is along the road A (northeast direction), mobile communication The terminal 10 determines that the terminal 10 is moving on the road A.
[0031]
At this time, the moving means of the mobile communication terminal 10 (type of route such as a general road, an expressway, a conventional railway, a bullet train, etc.) may be specified based on the moving speed of the mobile communication terminal 10. That is, based on the result of comparing the traveling speed with the type of route (general road, highway, conventional railway, Shinkansen, etc.), it is verified whether the predicted traveling route is correct. In particular, when a general road and an expressway are parallel to each other, it is possible to specify which route the mobile communication terminal 10 is traveling.
[0032]
Alternatively, the moving means may be specified based on the type of route (general road, highway, conventional railway, bullet train, etc.) and the moving speed of the mobile communication terminal 10 may be estimated.
[0033]
Furthermore, when it is determined that the moving speed is high based on the result of comparison between the moving speed and the predetermined speed, it is difficult to specify the route when the moving speed is low. And the likelihood of deviating from the specified route is high (that is, when the mobile communication terminal moves at high speed, the route is limited to a limited route such as a main road or a railroad). A highly accurate route prediction can be performed.
[0034]
Then, the position of the mobile communication terminal 10 after a predetermined time is predicted from the speed of the mobile communication terminal 10 calculated using the position of the mobile communication terminal 10 before the predetermined time.
[0035]
Further, the movement predicting device 30 uses the moving speed of the mobile communication terminal 10 to allow the mobile communication terminal 10 to leave the cell of the base station 20A and perform better communication with other base stations. The time to reach the point (handover point) is predicted. The point H is predetermined as a position on a main moving route depending on the distance from the base stations 20A to 20C and the signal reception quality (electric field strength, CIR, etc.) when the base station is installed. It is stored in the information database 40.
[0036]
Note that the estimated arrival time at the point H may be changed by further considering the moving speed of the mobile communication terminal 10. In other words, when the moving speed of the mobile communication terminal 10 is high, an earlier time is set as the point H expected arrival time from the expected arrival time calculated by dividing the moving distance required to the point H and the moving speed. As described above, if the expected arrival time at the point H is advanced when the moving speed is high, the handover process is started earlier, so that even if the handover process takes time, interruption of the call during the handover is suppressed. can do.
[0037]
Then, the movement prediction device 30 acquires, from the map information database 40, information on the cell of the base station having a cell adjacent to the cell of the base station 20A. Then, using the position of road A obtained from the map information and the information of the cell of the base station having an adjacent cell, the cell of which base station includes the path (road A) of mobile communication terminal 10 over a long distance. Is determined. Since the road A is included in the cell of the base station 20C for a long distance, it is better to hand over to the cell of the base station 20C when the mobile communication terminal 10 moves on the road A within the cell of the base station 20C. It is determined that the staying time is longer and the number of handovers can be reduced, which is advantageous.
[0038]
Then, before the mobile communication terminal 10 reaches the point H, the movement prediction device 30 notifies the base station 20C of the identification information of the mobile communication terminal 10 and the predicted time of reaching the cell of the base station 20C.
[0039]
Upon receiving the notification from the movement prediction device 30, the base station 20C reserves a channel for communicating with the mobile communication terminal 10, and notifies the movement prediction device 30 of the reserved channel. The movement prediction device 30 notifies the mobile communication terminal 10 of the coordinates of the H point at which the handover is performed, the scheduled time of the handover, the identification information of the base station C to be the handover destination, and the channel used.
[0040]
The movement prediction device 30 monitors the position of the mobile communication terminal 10, and when the mobile communication terminal 10 reaches the point H, a handover is instructed from the movement prediction device 30 to the mobile communication terminal 10, and the movement prediction device 30 uses a predetermined channel. Handover is performed to communicate with the base station 20C.
[0041]
The mobile communication terminal 10 determines that the point H has been reached based on the time or the coordinates notified from the movement prediction device 30, and performs a handover to communicate with the base station 20C using a predetermined channel. It may be configured to do so.
[0042]
Alternatively, the handover destination base station may be determined in consideration of the moving speed of the mobile communication terminal 10. That is, when the moving speed of the mobile communication terminal 10 is slow, the mobile station 10 leaves the cell of the base station 20A and stays in the cell of the base station 20B for a long time, so the handover is performed in the order of the base station 20A-the base station 20B-the base station 20C. To determine the base station of the handover destination. On the other hand, when the moving speed of the mobile communication terminal 10 is high, since the time that the mobile communication terminal 10 stays in the cell of the base station 20B after leaving the cell of the base station 20A is short, the handover to the base station 20B is performed without handover to the base station 20B. A handover destination base station is determined so as to perform handover to base station 20C.
[0043]
FIG. 4 is a flowchart showing the operation of the movement prediction device 30 according to the embodiment of the present invention.
[0044]
The movement prediction device 30 acquires the position information of the mobile communication terminal 10, and calculates the moving speed and the moving direction (S101). At this time, the moving speed and the moving direction may be acquired from the mobile communication terminal 10.
[0045]
Then, the movement prediction device 30 refers to the map information stored in the map information database 40, compares the map information with the acquired position information (S102), and moves the mobile communication terminal 10 on the movement route (road). Or a railway line) is specified, and a movement route is predicted (S103). Then, the mobile communication terminal 10 notifies the base station of the predicted time of arrival at the cell of the base station of the handover destination, and prepares for the handover (S104).
[0046]
Thereafter, the movement prediction device 30 further acquires the position information of the mobile communication terminal 10 (S105), and determines whether the mobile communication terminal 10 is moving on the predicted movement route (S106). If the mobile communication terminal 10 deviates from the predicted route, the process returns to step S101, and the mobile route of the mobile communication terminal 10 is predicted again (S101 to S103).
[0047]
On the other hand, if the mobile communication terminal 10 is moving on the predicted route, it is determined whether or not it has reached the planned handover position (S107). If the mobile communication terminal 10 has reached the handover scheduled position, the handover destination base station is notified of the fact and the handover is performed (S108). On the other hand, if the mobile communication terminal 10 has not reached the scheduled handover position, the process returns to step S105, and continues to monitor whether the mobile communication terminal 10 is moving on the predicted route (S106).
[0048]
【The invention's effect】
In the normal movement prediction, it is determined that the base station 20B close to the moving direction of the mobile communication terminal is suitable as a handover destination. Since the mobile station is limited to a specific facility, the base station to be handed over is selected by accurately predicting the mobile path of the mobile communication terminal using the map information. Since the user is heading for the cell of the station 20C, it can be determined that handover to the base station 20C is more advantageous, and the number of handovers can be reduced.
[0049]
Also, by preparing for handover in advance at the base station 20C, handover can be performed smoothly. In particular, when a mobile communication terminal moves at high speed, movement between cells is performed in a short time, and it is possible to prevent interruption of voice and disconnection of a line due to a delay in handover processing caused by frequent handover. it can.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a mobile phone according to an embodiment of the present invention.
FIG. 2 is a configuration diagram of a mobile communication system according to an embodiment of the present invention.
FIG. 3 is an explanatory diagram of a handover in the mobile communication system according to the embodiment of the present invention.
FIG. 4 is a flowchart showing an operation of the movement prediction device according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Antenna 2 Transmission / reception part 3 RF control part 4 Control part 5 Memory (RAM, ROM)
6 GPS unit 7 Operation unit (keyboard)
8 display unit 10 mobile communication terminals 20A to 20C base station 30 movement prediction device 40 map information database

Claims (11)

A mobile communication terminal, a wireless base station connected to the mobile communication terminal via a wireless communication line, and a movement prediction device for predicting a movement path of the mobile communication terminal, wherein the mobile communication terminal is a connection partner. In a mobile communication system that performs communication by switching a radio base station,
The mobile communication terminal includes position information detecting means for detecting a position of the mobile communication terminal,
The movement prediction device,
It is connected to a map information storage unit that stores map information,
Based on the position information detected by the position information detecting means and the map information obtained from the map information storage unit, predict a movement route of the mobile communication terminal,
Based on the movement route prediction result, predicting a next wireless base station to be connected to the mobile communication terminal, and controlling switching of a wireless base station to be connected to the mobile communication terminal. Communications system. The mobile communication system according to claim 1, wherein the movement prediction device notifies the wireless base station to which the mobile communication terminal is to connect next, of the identification information of the mobile communication terminal. The radio base station reserves a channel used by the mobile communication terminal when receiving notification of identification information of a mobile communication terminal that switches a connection partner to the radio base station. Mobile communication system. The mobile communication system according to any one of claims 1 to 3, wherein the position information detecting means is a GPS receiver. A mobile communication terminal used in the mobile communication system according to claim 1. A mobile communication terminal having position information detecting means for detecting a position of the mobile communication terminal; a wireless base station connected to the mobile communication terminal via a wireless communication line; and a movement prediction for predicting a movement route of the mobile communication terminal And a map information storage unit connected to the movement prediction device and storing map information. The map information storage unit is used in a mobile communication system in which the mobile communication terminal performs communication by switching a wireless base station to be a connection partner. In the movement prediction device,
Based on the position information detected by the position information detecting means and the map information obtained from the map information storage unit, predict a movement route of the mobile communication terminal,
Based on the prediction result of the movement route, a wireless base station to be connected next to the mobile communication terminal is predicted, and switching of a wireless base station to be connected to the mobile communication terminal is controlled. Movement prediction device. 7. The method according to claim 6, further comprising: notifying a wireless base station to which the mobile communication terminal is connected of identification information of the mobile communication terminal for reservation of a channel used by the mobile communication terminal. The movement prediction device according to the above. Calculating a moving speed of the mobile communication terminal based on a comparison result between a first position detected by the position information detecting means and a second position detected a predetermined time after detecting the first position; Speed calculation means,
Based on the information on the moving speed and the prediction result of the moving route, a wireless base station to be connected next to the mobile communication terminal is predicted, and switching of a wireless base station to be connected to the mobile communication terminal is controlled. The movement prediction apparatus according to claim 6, wherein the movement prediction is performed. A mobile communication terminal having position information detecting means for detecting a position of the mobile communication terminal; a wireless base station connected to the mobile communication terminal via a wireless communication line; and a movement prediction for predicting a movement route of the mobile communication terminal And a map information storage unit connected to the movement prediction device and storing map information. The map information storage unit is used in a mobile communication system in which the mobile communication terminal performs communication by switching a wireless base station to be a connection partner. A switching control method for a wireless base station,
Detecting the position of the mobile communication terminal,
Based on the position information of the mobile communication terminal and the map information obtained from the map information storage unit, predict a movement route of the mobile communication terminal,
Based on the prediction result of the movement route, a wireless base station to be connected next to the mobile communication terminal is predicted, and switching of a wireless base station to be connected to the mobile communication terminal is controlled. A switching control method for a wireless base station. Next, to the wireless base station to which the mobile communication terminal is connected, the identification information of the mobile communication terminal is notified,
The method according to claim 9, wherein the radio base station reserves a channel used by the mobile communication terminal. Calculating a moving speed of the mobile communication terminal based on a comparison result between a first position detected by the position information detecting means and a second position detected a predetermined time after detecting the first position; And
Based on the calculated information on the moving speed and the result of the prediction of the moving route, the next step is to predict the wireless base station to be connected to the mobile communication terminal, and to determine the wireless base station to be connected to the mobile communication terminal. 11. The switching control method for a wireless base station according to claim 9, wherein switching is controlled.

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