JP5470577B2 - Mobile terminal transmission power measuring device - Google Patents

Description

  The present invention relates to a portable terminal transmission power measuring apparatus used for measuring transmission power of a portable terminal while moving, and more particularly to a portable terminal transmission power measuring apparatus that measures in a state close to that actually used by a person.

  Research and development of a mobile phone system (hereinafter referred to as a terrestrial / satellite shared mobile phone system; referred to as STICS) in which a terrestrial communication system and a satellite communication system can communicate while sharing the same frequency band is underway. In STICS, radio wave interference from the ground system to the satellite communication system occurs, so it is important to evaluate the amount of interference.

  In an ordinary mobile phone system, the reception level at the base station is made as constant as possible, so that code demodulation by spectral despreading can be performed equally for any mobile terminal. Transmission output is controlled. For example, in a suburb where the distance between a mobile phone, which is a mobile terminal, and a base station that communicates with it is large, the transmission output is increased, and in a region where the distance is small, the transmission output is generally suppressed. Is well known. On the other hand, however, the density of base stations is generally higher in urban areas than in the suburbs, and the transmission output is usually set large despite the small distance between the base station and the mobile phone. This is because multipath fading is likely to occur because there are many obstacles such as buildings in the communication path, and congestion due to high density arrangement of mobile phones is severe.

  In this way, in the city, the transmission output is usually large and a huge number of mobile phones are used. Therefore, the radio waves from the city often cause radio wave interference on the satellite. In order to obtain the reference data of the interference amount, it is necessary to comprehensively measure the output level of the existing terrestrial mobile phone.

  Non-Patent Document 1 describes an experimental apparatus that records the output of a mobile terminal of the CDMA2000 system by placing a simulated human head with a mobile phone attached to a convertible vehicle. In this experimental apparatus, the power supplied from the power amplifier to the antenna of the portable terminal is recorded.

  This non-patent document 1 describes a system that operates a satellite and a ground system at the same frequency. In such a system, it is important in terms of system design to comprehensively evaluate the power transmitted by the mobile terminal used in the ground system in actual operation and estimate the amount of interference with the satellite system.

P.D. Karabanis et al .: "Interference Potential to MSS due to Terrestrial Reuse of Satellite Band Frequencies" AIAA- 2005-2028

  Comprehensively grasping transmission power from a large number of mobile terminals is possible by grasping transmission power during operation of individual mobile terminals in various operating states and performing statistical data processing.

  In addition, the transmission power required for the mobile terminal is greatly influenced by the positional relationship such as the distance and direction with the base station, the radio wave environment due to shielding around the mobile terminal, and the like. Therefore, a device that can efficiently measure the transmission power in such an operating state is required.

  An object of this invention is to implement | achieve the portable terminal transmission power measuring apparatus which enables the measurement of transmission power efficiently in the various operation state of a portable terminal.

The characteristics of the portable terminal power measuring device of the present invention are as follows. First, the present invention uses a mobile phone system that communicates between a mobile terminal and a base station and controls transmission power based on a command from the base station, and moves the transmission power during transmission from the mobile terminal to the base station. This is a transmission power measuring device for measuring on the body. More specifically, an external antenna connected to the mobile terminal with a feeder line, and a head phantom that is provided at a distance of one wavelength or less of the radio wave used for the communication from the external antenna and that is linked to the movement of the external antenna A branching device provided in the middle of the feeder line for branching a part of the transmission signal, a power measuring device for measuring the intensity of the radio wave branched by the branching device, and a measurement value by the power measuring device is recorded A recording device and a position detector for detecting the position of the moving body on the moving body are provided, and the transmission signal intensity is measured while moving.

In addition, the present invention includes an attitude controller that controls the orientation of the head phantom relative to the base station from a position obtained by the position detector and the position of the base station to a constant angle including zero. . When performing measurement while moving, the attitude controller maintains the orientation of the head phantom so as to face the base station, for example. Moreover, it maintains so that it may face the direction which provided the fixed offset angle from the direction of the base station. In some cases, it is also possible to perform maintenance control so that it faces a certain direction.

  In addition, a photographing device is provided that changes the photographing direction in conjunction with the movement of the head phantom and photographs the surrounding environment of the external antenna. In analyzing the transmission power measurement value, by referring to this captured video, if there is a sudden change in the transmission power, the cause can be easily estimated.

  In addition, the mobile body is provided with a position detector such as GPS (Global Positioning System), and other map information is recorded by recording the position information obtained by the position detector in parallel with the measured value obtained by the power measuring device. The measurement result can be examined by superimposing with.

  Since the transmission power from the mobile terminal is transmitted from the external antenna without using the internal antenna that is normally built into the mobile terminal body, various mobile phones can be measured without changing the relationship between the head phantom and the external antenna. It can be carried out. In addition, since the attitude control can be performed while maintaining the orientation with the base station, a change in transmission power due to the positional relationship with the base station can be easily measured, and the measurement efficiency can be improved. Furthermore, since the environment of the measurement point and the map information can be taken into consideration, analysis of the measurement result becomes easy.

It is a block diagram which shows the example of the portable terminal transmission power measuring apparatus of this invention provided with the camera and GPS receiver which image | photograph surrounding environment. It is a block diagram which shows the structural example of the portable terminal transmission power measuring apparatus of this invention, and is equipped with the portable terminal 1 which is going to measure transmission power, and the external antenna 2 for portable terminals, and the portable terminal 1 and the external antenna 2 are feeders. 3 and a coupler 4 installed between the external antenna 2 and the portable terminal 1 can extract a part of transmission power from the portable terminal 1. It is a block diagram which shows the internal structural example of the portable terminal 1 used for this portable terminal transmission power measuring apparatus of FIG. It is a block diagram which shows the structural example provided with the drive part 9 for remotely controlling rotation of the turntable. (A), (b) shows the case where the head is shielded between the external antenna and the base station, and the case where there is no head.

  Embodiments of the present invention will be described below in detail with reference to the drawings. In the following description, devices having the same function or similar functions are denoted by the same reference numerals unless there is a special reason.

  A portable terminal transmission power measuring apparatus according to the present invention will be described with reference to FIG. FIG. 2 shows an example of the configuration, which includes a mobile terminal 1 for measuring transmission power and an external antenna 2 for the mobile terminal. The mobile terminal 1 and the external antenna 2 are connected by a feeder line 3. A part of transmission power from the portable terminal 1 can be taken out by the coupler 4 installed between the portable terminals 1. The power measuring device 5 detects the power taken out from the coupler and measures the amount of power. For example, the power measuring device 5 is a measuring device having functions such as a spectrum analyzer 5b and a power meter 5a shown in FIG. The results measured by the power meter 5 are stored in a PC (personal computer) 6 and necessary data processing can be performed. A head phantom 7 simulating a human head is installed in the vicinity of the external antenna 2. The distance is approximately equal to or less than the wavelength of the radio wave used for communication. The turntable 8 fixes the external antenna 2 and the head phantom 7 and has a rotation mechanism. As a result, the orientation of the external antenna 2 can be changed while maintaining the positional relationship between the external antenna 2 and the head phantom 7.

  FIG. 3 shows an internal configuration of the mobile terminal 1 used in the mobile terminal transmission power measuring apparatus of FIG. 3 includes an antenna 1a built in the portable terminal, a switch 1b for switching between the built-in antenna and the external antenna 2 shown in FIG. 2, a transmitter / receiver demultiplexer 1c, a transmission unit 1d including a transmission amplifier, and a reception amplifier. And the like, and an external antenna terminal 1f for connecting the external antenna 2 and the like.

  FIG. 4 shows a configuration including a drive unit 9 for remotely controlling the rotation of the turntable 8. Although there is a control line for controlling the drive unit 9, it is omitted here. On this turntable, the external antenna 2 and the head phantom 7 used in the mobile terminal transmission power measuring apparatus shown in FIG. 2 are installed, and the orientation of the phantom, that is, the orientation of the external antenna 2 is maintained while maintaining the positional relationship. I can change it.

  Next, the operation of the mobile terminal transmission power measuring device will be described. The mobile terminal 1 is a mobile terminal that attempts to measure transmission power. The external antenna is normally used when the radio wave environment is bad. However, in the portable terminal transmission power measuring device, the external antenna 2 is connected for measurement.

  The operation of the mobile terminal 1 when the external antenna 2 is connected will be described with reference to FIG. In the portable terminal 1, a switch 1b for switching between an external antenna and a built-in antenna is provided between a built-in antenna 1a that shares transmission and reception and a transmitter / receiver demultiplexer 1c that separates a transmission signal and a received signal. When connected to the external antenna terminal 1f of the portable terminal 1, this is detected, and the switch 1b has a function of switching to the external antenna side.

  In FIG. 2, the external antenna 2 is connected to the external antenna terminal 1 f of the mobile terminal 1 via the coupler 4 by the feeder 3, and the coupler 4 is provided in the middle of the cable connecting the external antenna 2 and the mobile phone 1. Thus, it is possible to measure the transmission power by taking out a part of the transmission power from the transmission unit 1d of the portable terminal 1 from the coupler 4 and measuring it.

  When the mobile terminal 1 makes or receives a call with the external antenna 2 connected, the signal transmitted from the transmitter of the mobile terminal 1 is transmitted from the external antenna 2 to the base station through the feeder 3. Is done. The transmission power from the portable terminal 1 is controlled from the base station for each portable terminal, and when transmission is started, a part of the transmission power is sequentially measured by the power measuring device 5 with the coupler 4.

  In mobile phone systems, the effective radiated power required is determined based on the radio wave environment around the user and the positional relationship with the base station. Therefore, both when using the built-in antenna and when using the external antenna, If the gain does not change, the effective radiated power does not change with the same transmission power. Therefore, when the portable terminal transmits using the internal antenna 1a by calibrating the power value measured by the above method with an external antenna connected in consideration of the coupling degree of the feeder loss 3 and the coupler 4. The original transmission power can be obtained.

  Further, during actual operation of the mobile terminal, the transmission / reception environment of the mobile terminal is shielded by the human head. Therefore, when there is no influence of the head, such as when the external antenna is used away from the mobile terminal, an error occurs in the transmission output as compared with the case where the built-in antenna is used. In the present invention, the head phantom 7 is installed close to the external antenna in order to bring the portable terminal closer to the situation where it is actually used with the built-in antenna. For the head phantom 7, it is possible to simulate the effect of the shielding of the head received by the mobile terminal by using a phantom model that simulates the human head for SAR (Specific Absorption Rate) measurement It becomes.

  FIG. 4 shows a structure in which the external antenna 2 and the head phantom 7 are fixed to the turntable 8 and their directions are changed. 4A shows a case where the head is shielded between the external antenna and the base station, and FIG. 4B shows a case where the head is not shielded between the external antenna and the base station. Yes. In the current digital cellular phone system, the base station controls the transmission power of the portable terminal based on the error rate characteristics of the received signal received from the portable terminal, and the transmission power of the portable terminal changes depending on whether or not the human head is shielded . Therefore, in order to measure the transmission power from the mobile terminal, it is necessary to perform measurement corresponding to the degree of head shielding. When measuring the transmission power of the mobile terminal using the positional relationship with the base station as a parameter, in Non-Patent Document 1, it is necessary to measure by turning a mobile measurement vehicle with the mobile terminal fixed. According to the invention, power measurement corresponding to the degree of shielding of the head between the external antenna and the base station can be shortened by rotating the turntable 8 at various angles while maintaining the positions of the external antenna 2 and the head phantom 7. It can be done on time.

  FIG. 1 shows a configuration example for further facilitating the analysis of the obtained data using the above configuration. This portable terminal transmission power measuring device is equipped with a measurement vehicle. An external antenna 2, a head phantom 7, a camera, an antenna of a GPS receiver 11, and the like are installed on the roof of the measurement vehicle, and the portable terminal 1 and the PC 6 A power meter 5a, a spectrum analyzer 5b, a turntable controller and the like are installed inside the measurement vehicle. Here, the ground height of the external antenna is almost the height when a person of average height stands and calls.

  In general, in urban areas with many high-rise buildings, it is known that communication paths have many obstacles and multipath fading is likely to occur. For this reason, recording the environment in which the mobile terminal is placed together with the measurement value of the transmission power of the mobile terminal is useful information for analyzing the measurement data. For this reason, as shown in FIG. 1, the camera 12 which image | photographs the surrounding environment of the said head phantom is provided. Information on the presence or absence of multipath fading can be obtained from the video of the building, and information on congestion due to high-density arrangement of the mobile terminals can be obtained from the crowded situation video. This camera is preferably a camera capable of photographing all directions, but may be a camera fixed to the turntable 8 so as to change the photographing direction in conjunction with the movement of the head phantom.

  Further, as shown in FIG. 1, for example, a position detector such as a GPS (Global Positioning System) receiver 11 is provided, and the position information of the measurement point by the position detector is parallel to the measurement value by the power measurement device. Record on PC6. As a result, the measurement result can be examined by overlapping with other map information.

  Further, by using the result of the position detector such as the GPS receiver 11, the orientation of the head phantom 7 with respect to the base station whose position is fixed is configured by the PC 6, the turntable controller 10, and the drive unit 9. It is possible to perform control by the attitude controller to maintain a constant angle including zero. For example, when performing measurement while moving, the attitude controller maintains the orientation of the head phantom so as to face the base station, for example. Moreover, it maintains so that it may face the direction which provided the fixed offset angle from the direction of the base station. Depending on the case, it is also possible to control to face a certain direction instead of the direction of the base station.

  In the above example, an example of the mobile terminal transmission power measuring device installed on the vehicle is shown, but the measurement in this case is limited to the measurement on the road. Therefore, for example, when measuring on a sidewalk or in a park, the mobile terminal transmission power measuring device of the present invention is equipped on a wheeled carrier (wagon), so that it is easy to measure in places where vehicles cannot enter Can be done. Further, by installing the portable terminal transmission power measuring device of the present invention on a ship or the like, transmission power measurement in a coastal area can be easily performed.

DESCRIPTION OF SYMBOLS 1 Mobile terminal 2 External antenna 3 Feeding line 4, 4a, 4b Coupler 5, 5a, 5b Power measuring device 6 PC
7 Head phantom 8 Turntable 9 Drive unit 10 Turntable controller 11 GPS receiver 12 Camera

Claims (3)

Transmission power measurement that measures the transmission power at the time of transmission from a mobile terminal to a base station on a mobile body, with respect to a mobile phone system that communicates between the mobile terminal and the base station and controls the transmission power based on a command from the base station In the device
An external antenna connected to the mobile terminal with a feeder,
A head phantom provided at a distance of one wavelength or less of the radio wave used in the communication from the external antenna and interlocking with the movement of the external antenna;
A branching device provided in the middle of the feeder line for branching a part of the transmission signal;
A power measuring device for measuring the intensity of the radio wave branched by the branching device;
A recorder for recording the measured value by the power meter ; a position detector for detecting the position of the moving body on the moving body;
An attitude controller that controls the orientation of the head phantom relative to the base station from a position by the position detector and a position of the base station to a constant angle including zero;
With
A portable terminal transmission power measuring apparatus capable of measuring transmission signal strength while moving.   The mobile terminal transmission power measuring device according to claim 1, further comprising a photographing device that changes a photographing direction in conjunction with movement of the head phantom and photographs a surrounding environment of the external antenna. The mobile terminal transmission power measuring device according to claim 1, wherein the position by the position detector is recorded in parallel with the measurement value by the power measuring device.

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