JP4099650B2 - Mobile communication terminal and moving speed detection method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mobile communication terminal having a function of measuring a moving speed, and more particularly to a mobile communication terminal that selects a wireless communication system to be connected according to the moving speed.
[0002]
[Prior art]
Currently, mobile communication terminals such as mobile phones compatible with two wireless communication systems have been put into practical use and newly proposed. For example, there are portable communication terminals that can be used as both PDC and PHS terminals. Moreover, what can be used as a terminal of both PDC and W-LAN, and what can be used as a terminal of both W-CDMA and W-LAN are proposed.
[0003]
For example, consider a mobile communication terminal that supports both PDC and PHS systems. PDC covers a wide area for each base station, while PHS covers it. On the other hand, PHS has a higher communication speed than PDC. For example, when data communication is performed, data transfer is temporarily interrupted when a handover occurs. Therefore, when the mobile communication terminal has a high moving speed, the mobile communication terminal is connected to a PDC having a wide base station coverage area and a low frequency of handover. Is preferred. On the other hand, when the moving speed is low, it is preferable to connect to a PHS having a high communication speed. Similarly, with respect to portable communication terminals compatible with both PDC and W-LAN systems, PDC has a wide coverage area of each base station but has a low communication speed. W-LAN is a wireless communication system that constitutes a W-LAN system. Although the device cover area is small, the communication speed is fast. The relationship between W-CDMA and W-LAN is the same. Note that a base station of a mobile communication system such as PDC, W-CDMA, or PHS, or a wireless device configuring a W-LAN is hereinafter referred to as a wireless station.
[0004]
In this way, the two wireless communication systems supported by one mobile communication terminal have different characteristics from each other and are in a complementary relationship. In many cases, one radio communication system has a wide coverage area of radio stations, and the other radio communication system has a high communication speed. Therefore, when selecting the wireless communication system to which the mobile communication terminal is connected, it is effective to select according to the moving speed. It is preferable that the mobile communication terminal can measure the moving speed without adding an additional device so as not to impair portability such as small size, light weight, and low power consumption.
[0005]
In an example of a conventional method for measuring a moving speed (see Patent Document 1), first, a radio wave having a predetermined frequency is transmitted from a mobile communication terminal. A plurality of base stations receive radio waves from mobile communication terminals. Radio waves received by a plurality of base stations include a Doppler shift accompanying the movement of the mobile communication terminal. The moving direction of the moving object is detected from the spatial distribution of the Doppler shift amount detected at each base station.
[0006]
In another example of the conventional method for measuring the moving speed (see Patent Document 2), first, the mobile communication terminal detects the fading frequency (f) of the received signal. The fading frequency (f), the predetermined wavelength (λ) of the received signal, and the moving speed (V) of the mobile communication terminal have a relationship of f = V / λ. The mobile communication terminal calculates the moving speed (V) using this relational expression.
[0007]
In still another example of the method for measuring the moving speed (see Patent Document 3), first, a radio control channel signal is transmitted in a time division manner from each base station. Next, the mobile communication terminal measures the reception level of the radio control channel from each base station, and estimates the moving speed from the fluctuation of the reception level from each base station.
[0008]
Yet another example of the method for measuring the moving speed (see Patent Document 4) is that the mobile communication terminal detects the moving speed by a gyro. According to Patent Document 4, the mobile communication terminal can use the detected moving speed to perform handoff at a moving speed equal to or higher than a predetermined speed and a wireless communication system (PHS) that cannot be handed off at a predetermined speed or higher. One of the wireless communication systems (PDC) of the system is selected.
[0009]
[Patent Document 1]
JP-A-7-111675 [Patent Document 2]
JP-A-10-261989 [Patent Document 3]
Japanese Patent No. 2669288 [Patent Document 4]
Japanese Patent Laid-Open No. 10-290474
[Problems to be solved by the invention]
In the moving speed detection method described in Patent Document 1, it is necessary for each base station to receive radio waves from all portable communication terminals, regardless of whether or not they are used for actual communication. Therefore, processing load is applied to each base station.
[0011]
Further, in any of the devices, it is necessary to collectively determine the moving speed of the mobile communication terminal by collecting Doppler shift amounts detected in each base station. And the apparatus needs to judge about all the mobile communication terminals. Therefore, a large processing load is applied to the apparatus.
[0012]
In the moving speed detection method described in Patent Document 2, a relative speed with respect to a base station that is a source of a signal that detects a fading frequency is detected. Therefore, for example, as shown in FIG. 5, when the mobile communication terminal 51 is moving on the circumference centered on the base station 52, the movement speed of the mobile communication terminal 51 is detected as zero, and wireless communication such as PHS is performed. Connected to the system. However, at that time, it may actually be moving at high speed, and there is a possibility that it should be connected to a wireless communication system such as a PDC.
[0013]
In the moving speed detection method described in Patent Document 3, the reception level does not change unless the relative distance to the base station changes. Therefore, an accurate moving speed cannot be detected depending on the moving route of the mobile communication terminal.
[0014]
In the moving speed detection method described in Patent Document 4, it is necessary to mount a gyro on the portable communication terminal, which is not preferable for portable communication terminals that require portability such as small size and light weight.
[0015]
An object of the present invention is to provide a mobile communication terminal capable of detecting an actual moving speed rather than a relative speed with a base station without impairing portability and without applying a load to a radio communication system.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, a moving speed detection method of the present invention is a moving speed detection method in a mobile communication terminal that receives radio waves from a plurality of radio stations, the step of receiving radio waves from at least two radio stations. And detecting the relative speed with each radio station using radio waves from each radio station, and determining the moving speed from the relative speed with each radio station and the position of the mobile communication terminal.
[0017]
Therefore, according to the present invention, the mobile communication terminal detects the relative speed with at least two radio stations, and detects its own moving speed from the relative speed and its own position.
[0018]
Further, the moving speed detection method of the present invention may detect the relative speed with each radio station from the frequency of the radio wave from each radio station using the Doppler effect.
[0019]
The moving speed detection method of the present invention may further include a step of obtaining the position of the mobile communication terminal using the position information of each radio station and the radio wave from each radio station.
[0020]
Moreover, the moving speed detection method of the present invention may further include a step of acquiring position information of each radio station from each radio station. Alternatively, the moving speed detection method of the present invention may further include a step of previously recording the position information of each wireless station on the mobile communication terminal.
[0021]
Further, the moving speed detection method of the present invention may obtain the position of the mobile communication terminal from the position information of each radio station and the reception intensity of the radio wave from each radio station.
[0022]
The mobile communication terminal of the present invention is a mobile communication terminal that receives radio waves from a plurality of radio stations, and a speed detection unit that detects a relative speed with each radio station using radio waves received from at least two radio stations; And a speed composition unit that obtains a moving speed from the relative speed with each wireless station detected by the speed detection unit and the position of the mobile communication terminal.
[0023]
In addition, the speed detection unit may detect the relative speed with each radio station from the frequency of the radio wave from each radio station using the Doppler effect.
[0024]
In addition, the mobile communication terminal of the present invention may further include a position detection unit that obtains the position of the mobile communication terminal using position information of each radio station and radio waves from each radio station.
[0025]
Further, the position detection unit may acquire the position information of each wireless station from each wireless station. Alternatively, the position detection unit may store the position information of each wireless station in advance.
[0026]
Further, the position detection unit may obtain the position of the mobile communication terminal from the position information of each wireless station and the reception intensity of the radio wave from each wireless station.
[0027]
The portable communication terminal of the present invention can be connected to at least two wireless communication systems, and further includes a system switching unit that selects any one of the wireless communication systems according to the moving speed obtained by the speed combining unit. May be.
[0028]
Therefore, the mobile communication terminal of the present invention detects the relative speed with at least two radio stations by the speed detection unit, detects its own moving speed from the relative speed and its own position, and is suitable for its own moving speed. Select a wireless communication system.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described in detail with reference to the drawings.
[0030]
Here, a mobile phone corresponding to two mobile communication systems of PDC and PHS is illustrated. FIG. 1 is a diagram illustrating the movement of the mobile phone according to the present embodiment. Referring to FIG. 1, the mobile phone 1 is moving near the base stations 2 and 3 at a moving speed V. These base stations 2 and 3 may be PDC base stations or PHS base stations. Further, one of the base stations 2 and 3 may be a PDC base station and the other a PHS base station.
[0031]
FIG. 2 is a block diagram showing the configuration of the mobile phone according to the present embodiment. Referring to FIG. 2, the mobile phone 1 includes an antenna 11, speed detection units 12 and 13, a position detection unit 14, a speed synthesis unit 15, and a system switching unit 16.
[0032]
The antenna 11 receives radio waves from at least two base stations (here, base stations 2 and 3).
[0033]
The speed detectors 12 and 13 each detect a relative speed with the base station using the received radio wave from one base station. The speed detectors 12 and 13 use the Doppler effect for detecting the relative speed.
[0034]
The detection of the relative speed of the mobile phone 1 with the base station 2 will be described. The base station 2 transmits radio waves having a predetermined frequency f20 and wavelength λ20. However, when the mobile phone 1 is moving, the frequency f2 of the signal received by the mobile phone 1 is different from the frequency f20. When the relative speed of the mobile phone 1 with the base station 2 is V2, the relationship V2 = (f2−f20) · λ20 is established. The relative speed V2 can be obtained from this equation.
[0035]
Detection of the relative speed of the mobile phone 1 with the base station 3 can be performed in the same manner. The base station 3 transmits radio waves having a predetermined frequency f30 and wavelength λ30, and assuming that the relative speed is V3, the relationship V3 = (f3−f30) · λ30 is established.
[0036]
The position detection unit 14 detects the position of the mobile phone 1. At that time, the position detection unit 14 knows in advance the strength of the radio wave transmitted from each of the base stations 2 and 3 (transmitted radio wave intensity). Then, the position detection unit 14 measures the intensity of the radio waves received from the base stations 2 and 3 (received radio wave intensity). Then, the position detector 14 obtains each relative distance from the base stations 2 and 3 from the attenuation obtained by comparing the received radio wave intensity with the transmitted radio wave intensity from the base stations 2 and 3.
[0037]
The position detection unit 14 detects the position of the mobile phone 1 from the relative distances to the base stations 2 and 3 obtained as described above. In that case, the position detection part 14 has acquired each positional information from each base station 2 and 3 previously.
[0038]
FIG. 3 is a diagram for explaining position detection of the mobile phone according to the present embodiment. Here, the relative distance between the mobile phone 1 and the base station 2 is r2, and the relative distance with the base station 3 is r3. Referring to FIG. 3, the positions of the base stations 2 and 3 are determined according to the position information, and a circle S2 having a radius r2 is drawn with the position of the base station 2 as the center. Similarly, a circle S3 having a radius r3 is drawn with the position of the base station 3 as the center. The intersection of these two circles S2 and S3 is the position of the mobile phone 1. Although there are two intersections as shown in FIG. 3, since the position information of the mobile phone 1 is only used to determine the moving speed, it is not necessary to specify which intersection is the actual position.
[0039]
The speed synthesizer 15 obtains the moving speed of the mobile phone 1 from the relative speeds V2 and V3 detected by the speed detectors 12 and 13 and the position information of the mobile phone 1.
[0040]
FIG. 4 is a diagram for explaining how to determine the moving speed of the mobile phone according to the present embodiment. As shown in FIG. 4, a vector of the relative speed V2 is drawn from the position of the mobile phone 1 on a straight line L2 connecting the base station 2 and the mobile phone 1, and the mobile phone is carried on the straight line L3 connecting the base station 3 and the mobile phone 1. A vector of the relative speed V3 is drawn from the position of the telephone 1. Then, a point P at which the perpendicular to the straight line L2 intersects the straight line L2 at the end point of the vector of the relative speed V2 and the perpendicular to the straight line L3 intersects the straight line L3 at the end point of the vector of the relative speed V3 is obtained. The magnitude of the vector from the position of the mobile phone 1 to the point P is the moving speed V of the mobile phone 1.
[0041]
The system switching unit 16 compares the moving speed V of the mobile phone 1 with a predetermined threshold, selects PDC when the moving speed V is greater than the threshold, and PHS when the moving speed V is less than the threshold. Select.
[0042]
The mobile phone 1 having the above-described configuration first detects the relative speed between the two base stations 2 and 3 by the speed detectors 12 and 13 and detects its own position by the position detector 14. Next, the mobile phone 1 obtains its moving speed by using the speed synthesizing unit 15 using the relative speed with the base stations 2 and 3 and its own position. Next, the mobile phone 1 selects either PDC or PHS according to its moving speed.
[0043]
As described above, the mobile phone 1 according to the present embodiment detects the relative speed between the base stations 2 and 3 from the frequencies of radio waves received from the two base stations 2 and 3, and Since it is possible to detect its own position from the intensity of the received radio wave and to determine its own moving speed from its relative speed to the base stations 2 and 3 and its own position information, it is possible to provide a wireless communication system without providing an additional device. It is possible to obtain a moving speed without imposing a load on the mobile phone and select an appropriate wireless communication system.
[0044]
In the present embodiment, the speed detectors 12 and 13 detect the relative speed with the base stations 2 and 3 using the Doppler effect, but the present invention is not limited thereto. The speed detectors 12 and 13 may obtain the relative speed from the fading frequency, or may obtain the relative speed from the change in the intensity of the received radio wave.
[0045]
In the present embodiment, the position detection unit 14 acquires the position information of the base stations 2 and 3 from the base stations 2 and 3, but the present invention is not limited thereto. The position detection unit 14 may store the position information of the base stations 2 and 3 in advance. In addition, there is a location information server (not shown) that stores the location information of each base station 2, 3, and the location detector 14 of the mobile phone 1 acquires the location information of the base stations 2, 3 from the location information server. It is good to do.
[0046]
In the present embodiment, the position detection unit 14 determines the position information of the mobile phone 1 from the position information of the base stations 2 and 3 and the reception intensity of the radio waves from the base stations 2 and 3. Is not limited to this. The position detection unit 14 may have a GPS, and may directly obtain the position of the mobile phone 1.
[0047]
In the present embodiment, the cellular phone corresponding to both the PDC and PHS systems is illustrated, but the present invention is not limited thereto. The present invention is also applicable to portable communication terminals compatible with PDC and W-LAN, portable communication terminals compatible with W-CDMA and W-LAN, and the like. In a W-LAN, a base station in a mobile communication system such as PDC or PHS is provided with a wireless device constituting the base station. In that case, the mobile communication terminal uses radio waves from the wireless devices constituting the W-LAN instead of radio waves from the base station. Hereinafter, a base station of a mobile communication system, a W-LAN wireless device, and the like are referred to as a wireless station. That is, the mobile communication terminal including the mobile phone detects the moving speed using the radio wave from the radio station.
[0048]
In the present embodiment, the moving speed is used to select two wireless communication systems, but the present invention is not limited to this. The present invention can be widely applied to portable communication terminals that measure moving speed.
[0049]
【The invention's effect】
According to the present invention, the mobile communication terminal detects the relative speed with at least two radio stations, and detects the movement speed of the mobile communication terminal based on the relative speed and its own position. The actual moving speed that is not relative to the radio station can be obtained without imposing a burden on the system including the radio station.
[0050]
Further, according to the present invention, the mobile communication terminal selects a radio communication system suitable for the detected moving speed of the mobile communication terminal, so that no additional device is provided and any radio communication system is not burdened. An appropriate wireless communication system can be selected.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a movement of a mobile phone according to an embodiment.
FIG. 2 is a block diagram showing a configuration of a mobile phone according to the present embodiment.
FIG. 3 is a diagram for explaining position detection of the mobile phone according to the embodiment.
FIG. 4 is a diagram for explaining how to determine the moving speed of the mobile phone according to the present embodiment.
FIG. 5 is a diagram showing an example in which it is difficult to detect the moving speed by the conventional moving speed detecting method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Mobile telephone 11 Antenna 12, 13 Speed detection part 14 Position detection part 15 Speed synthesis part 16 System switching part 2, 3 Base station S2, S3 Circle L2, L3 Straight line

Claims (11)

A mobile speed detection method in a mobile communication terminal that receives radio waves from a plurality of radio stations,
Receiving radio waves from at least two radio stations;
Detecting a relative speed with each radio station using radio waves from each radio station;
The have a step of determining the moving speed from the position of the relative velocity, and the mobile communication terminal with the wireless stations,
Using the Doppler effect, the relative speed with each radio station is detected from the frequency of the radio wave from each radio station.
Moving speed detection method. Further comprising, moving speed detection method of claim 1 wherein the step of determining the position of the mobile communication terminal using a radio wave from the position information and the respective radio station of each radio station. The moving speed detection method according to claim 2 , further comprising a step of acquiring position information of each radio station from each radio station. The moving speed detection method according to claim 2 , further comprising a step of previously recording the position information of each wireless station in the mobile communication terminal. 5. The moving speed detection method according to claim 2 , wherein the position of the mobile communication terminal is obtained from position information of each wireless station and reception intensity of radio waves from each wireless station. A mobile communication terminal that receives radio waves from a plurality of wireless stations,
A speed detector for detecting a relative speed with each of the radio stations using radio waves received from at least two radio stations;
Have a velocity synthesis portion for obtaining the moving speed from the position of the relative velocity, and the portable communication terminal with the respective radio station detected by the speed detection section,
The speed detection unit is a mobile communication terminal that detects a relative speed with respect to each radio station from a frequency of a radio wave from each radio station using a Doppler effect . The mobile communication terminal according to claim 6 , further comprising a position detection unit that obtains the position of the mobile communication terminal using position information of each wireless station and radio waves from each wireless station. The mobile communication terminal according to claim 7 , wherein the position detection unit acquires position information of each wireless station from each wireless station. The mobile communication terminal according to claim 7 , wherein the position detection unit stores in advance position information of each wireless station. The mobile communication according to any one of claims 7 to 9 , wherein the position detection unit obtains the position of the mobile communication terminal from position information of each radio station and reception intensity of radio waves from each radio station. Terminal. The system switching unit according to any one of claims 6 to 10 , further comprising a system switching unit that is connectable to at least two radio communication systems and selects any one of the radio communication systems according to a moving speed obtained by the speed synthesis unit. The mobile communication terminal according to item.

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