JPH08179028A - Present position detection service system for mobile station in cellular telephone - Google Patents

Abstract

PURPOSE: To estimate the present position of a mobile station by allowing the mobile station to report the received signal levels from three or more base stations including a traffic base station to the traffic base station, and obtaining the propagation losses of the radio waves of the base stations. CONSTITUTION: When a moving body requests the present position information, a traffic base station instructs the moving body to report the radio wave levels from three adjacent base stations including the traffic base station, and the traffic base station obtains the radio wave propagation losses of the base stations from the reported level difference of the radio waves. The antenna height of the moving body is quantified with the average antenna height, correction terms for individual base stations are experimentally obtained in advance, and the distances between the base stations and the moving body can be obtained when the propagation losses are found. No change of hardware is required at all for the moving body and the base stations, and this method can be implemented when only the base station software is somewhat changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile station current position detection service system in a cellular telephone.

[0002]

2. Description of the Related Art At present, there are various services provided by telephone, such as weather, current time, inquiry of telephone number by the address of the other party who wants to make a call, and they are widely used. On the other hand, a cellular type mobile communication system has been introduced and rapidly spread in order to realize the essential requirement of communication "anytime, anywhere with anyone" in the conventional fixed telephone system. However, in mobile communication, the current position of the mobile station is unspecified, and realization of a method for easily knowing the current position is expected. Conventional systems have very large scale systems and devices, such as GPS (Global Positioning System). Despite the realization of a cellular telephone system corresponding to the characteristics of a mobile unit, a service for providing position information of the mobile unit by telephone is not currently provided.

[0003]

As a method for detecting the position of a moving body using a cellular radio telephone system,
For example, "position detection method" by Nishikawa et al. (Japanese Patent Laid-Open No. 3-235)
No. 077) has been proposed. The content is shown in FIG. 2. The present technology uses a specific telephone number transmitted from the mobile unit 101 in the radio telephone system for communicating between the mobile unit, the wireless telephone unit 101 and the wireless telephone station base station. Upon receiving the response signal from the wireless telephone base stations 302, 303, 304 of three or more stations located near the mobile unit 101, the position detection signal is transmitted to the mobile unit 101, and the time from the reception to the response is calculated. The position of the moving body 101 is calculated, and the calculated output is notified to the moving body 101.

However, in the present technology, in addition to the function of the conventional base station, a pulse signal transmitting device to the mobile station and a response signal detecting device are required, and complicated information processing between adjacent base stations is required. .

These conventional techniques increase the system scale of the current cellular telephones and require a great deal of information processing. For example, the above-mentioned technique requires a pulse signal transmitting device for a mobile station and a response signal detecting device in addition to the function of a conventional base station, and requires complicated information processing between adjacent base stations.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems of the prior art and to easily and efficiently estimate the current position of a moving body by using a cellular radio telephone system. , A method of providing the current position information to the mobile body is proposed.

In order to solve the above problems, the present invention is a cellular telephone service system, in which a mobile station reports to a communication base station the received signal levels from three or more base stations including a communication base station. , The communication base station obtains the propagation loss of each base station radio wave and obtains the distance between the mobile station and each base station to obtain the current position information of the mobile station.

[0008]

According to the above structure, the communication base station can know the propagation loss of the radio wave of each base station based on the information from the mobile unit, and can estimate the current position of the mobile unit based on the loss.

[0009]

[Embodiment] In a cellular telephone, in order to perform smooth cell switching, a mobile unit changes the strength of the radio waves of other base stations together with the radio waves of the communication base station by an instruction of the communication base station during a call with the communication base station. It also has a function to detect and report the result to the communicating base station. Therefore, if there is a request for current position information from the mobile unit, the communicating base station instructs the mobile unit to report the radio wave level of the adjacent base station. When the measurement result is transmitted from the mobile body, the communication base station estimates the current position of the mobile body from the level difference of the radio waves from the respective base stations. That is, the communication base station obtains the propagation loss of the radio wave of each base station based on the information from the mobile body. For example, Hata's “Empirical formul”
a for propagation loss in land mobile radio ”, IEE
In E Trans. Veh. Technol., Vol. VT-29,3 (1980), the propagation loss in urban areas is shown as follows.

[0010]

[Equation 1]

If the antenna height of the mobile station is made constant to the average antenna height and the correction term a (hm) at each base station is experimentally obtained, the propagation loss is known to allow the base station and the mobile unit to communicate with each other. The distance of can be calculated. Therefore,
The mobile unit reports the reception signal level from three or more base stations including the communication base station to the communication base station, and the communication base station obtains the propagation loss of each base station radio wave to obtain the communication loss between the mobile station and each base station. The position of the moving body can be calculated by obtaining the distance.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic explanatory view showing an embodiment of the present invention. In FIG. 1, A is a mobile and base station B1
Is the position of each of the base stations B2 and B3 (x
2, y2), (x3, y3) and antenna heights h2, h3
Remembers the value of.

When the mobile station A requests the base station B1 for the current position information, the base station B1 outputs a transmission output of P1 [dBm].
And request the mobile unit A to report the reception level. The output P1 receives the propagation loss L1 [dB] represented by the equation (1) and becomes the electric power of P1−L1 [dBm] and arrives at the moving body A. Assuming that the mobile unit A has a power amplification factor of G [dB], the mobile unit A transmits R to the base station B1.
It reports to the base station B1 that the received signal level of 1 = P1−L1 + G [dBm] is obtained. Since fc and hm in equation (1) are known, the following equation is obtained by summing the constant terms.

[0015]

[Equation 2]

Next, the base station B1 informs the base station B2 of the frequency f.
At c2, the carrier of power P2 is commanded to be output, and the mobile unit A is requested to report its reception level. As a result, the following equation is similarly obtained.

[0017]

(Equation 3)

Similarly, the following equation is obtained for the base station B3.

[0019]

[Equation 4]

For the three variables G, x, y, (2)-
Expression (4) is established, and the position (x, y) of the moving body A is obtained. Since the instantaneous value of the received signal fluctuates due to fading or the like, the accuracy is further increased to B when the integration of the received signal is taken into consideration.

[0021]

As described above, according to the configuration and method of the present invention, the movement in the cellular radiotelephone system can be performed by performing very simple calculation processing without increasing the scale of the conventional cellular system. It provides a body position detection service. This system does not require any addition or modification of hardware at the base station or mobile station, and the service can be realized by only a slight modification of the base station software. In addition, it is expected that the position can be specified with the same accuracy as in a large-scale system by conducting a propagation experiment in each base station and using a mathematical formula that takes into account the peculiarities of each cell.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of the present invention.

FIG. 2 is a diagram showing a conventional position detection method.

[Explanation of Codes] A: Mobile B1: Base station B2: Base station B3: Base station

Claims (1)

[Claims] 1. In a cellular telephone service system, a mobile station reports to a communication base station the received signal levels from three or more base stations including a communication base station, and the communication base station transmits the radio wave of each base station. A mobile station current position detection service system characterized in that the current position information of the mobile station is obtained by obtaining the propagation loss and the distance between the mobile station and each base station.