KR100247000B1 - Method for presuming location of mobile station in mobile telecommunication system - Google Patents

Abstract

end. The technical field to which the invention described in the claims belongs

Direct sequence code division relates to a Darwin-connected mobile communication system.

I. The technical problem that the invention is trying to solve

An automatic positioning system and method using a direct spread code division Darwin access mobile communication base station without using a satellite.

All. Summary of Solution of the Invention

Direct sequence code division in commercial service The Darwin access type mobile communication base station system additionally transmits the location information related to the currently installed location, and the mobile communication terminal analyzes the location signals transmitted from the plurality of base stations and coordinates of the area where the current terminal is located. It is about a device that calculates the number of mobile devices without the need for a separate satellite.

la. Important uses of the invention

Used to automatically estimate the location of the mobile communication terminal.

Description

Automatic positioning system and method {METHOD FOR PRESUMING LOCATION OF MOBILE STATION IN MOBILE TELECOMMUNICATION SYSTEM}

The present invention relates to an apparatus and a method for measuring the position of a mobile communication terminal, and in particular, to direct spreading code division multiple access (DS-CDMA). A positioning system and method are disclosed.

The technique of locating the exact position of the moving body has been used for navigation of ships and aircrafts for a long time, but it has been used for personal or vehicle use since the early 1990s when the Global Positioning System (GPS), an automatic positioning system using satellites, was used to be. GPS receives time and position information from 24 satellites in the air and finds out the current three-dimensional position and time by the principle of triangulation.

라고 가정하고 광속이 C일 때 다음과 같이 계산된다.FIG. 1 illustrates a configuration example of a conventional positioning system using satellites, and shows a state in which a mobile communication terminal (TE) receives information on time and location from a plurality of satellites (SAT1 to SAT4). In this case, the coordinates and time of the user, that is, the mobile communication terminal TE are referred to as (Xu, Yu, Zu, Tu), and the coordinates and time of the first satellite SAT1 are represented as (X1, Y1, Z1, T1). Pseudo distance between the mobile communication terminal TE and the first satellite SAT1 indicates that a user's clock error

Is assumed to be calculated as follows.

를 알아내기 위해서는 4개의 식이 필요하고, 이것은 4개 이상의 위성으로부터 신호를 받을 수 있으면 해결된다. 실제 운용되는 위성은 4개의 괘도에 각 6개씩 총 24개가 있으므로 가시 범위에서 접할 수 있는 위성의 개수는 항상 5개 이상이다. 이렇게 하여 알아낼 수 있는 사용자의 위치오차는 현재 수 100미터 내외이다.Since the coordinates of the satellite are known in advance, the unknowns Xu, Yu, Zu,

Four equations are needed to figure out the problem, and this is solved if we can receive signals from four or more satellites. Since there are 24 satellites in total, each of which is six on four orbits, there are always five or more satellites in the visible range. In this way, the user's location error can be found within a few hundred meters.

Such a method can in principle simply find a relatively accurate position. However, it has the following limitations. First, a special expensive expensive receiver using 1.5 GHz or 1.2 GHz that is not commercially available must be used separately. Second, since a signal must be received from a satellite at an altitude of 20,000 km, a high sensitivity sensitive reception method should be used. Third, since stable operation can be ensured only in the visible range of the satellite, it is difficult to position the obstacle. Fourth, since the original purpose is military, it may be disturbed depending on the needs of the military. Fifth, since the satellite is not a stationary orbit but a 12-hour orbit, the position of the satellite changes frequently and the position must be recalculated every time it is positioned. For example, the GPS signal receiver disclosed in US Pat. No. 5,402,441 has a signal tracking unit to perform its function. Sixth, the accuracy of positioning is fixed.

Accordingly, an object of the present invention is to provide an automatic positioning system and method using a direct spread code division Darwin access mobile communication base station apparatus without using a satellite.

1 is a configuration diagram of a conventional positioning system using a satellite

2 is a block diagram of a mobile communication system having a cell structure to which the present invention is applied;

FIG. 3 illustrates an example of information transmitted on any base station of FIG. 2 and a wireless channel of the base station.

4 is a structural diagram of a pilot channel

5 is a structural diagram of a pilot channel when broadcasting with a pseudo-noise code with a plurality of base stations each having a predetermined offset difference.

FIG. 6 is a timing diagram illustrating a difference in time between pilot channel information corresponding to propagation delay according to a difference in distance;

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals have the same reference numerals as much as possible even if displayed on different drawings. In addition, in the following description, there are many specific details such as components of a specific circuit, which are provided to help a more general understanding of the present invention, and the present invention may be practiced without these specific details. It is self-evident to those who have knowledge. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

2 is a configuration diagram of a mobile communication system having a cell structure to which the present invention is applied. In general, a mobile communication system has a structure in which base station coverage of a limited area called a cell is repeated. In the present embodiment, three cells are assumed and described for convenience. Reference numeral MS is a user terminal. The three base stations closest to the user terminal MS are denoted as BS1, BS2, and BS3, respectively. Coordinates of the user terminal MS and the three base stations BS1, BS2, and BS3 are represented as Pu, P1, P2, and P3, respectively. In addition, the distance between the user terminal (MS) and the three base stations (BS1, BS2, BS3) is indicated as R1, R2, R3, respectively. At this time, the coordinate P is represented by (X, Y, Z) in a three-dimensional form. Since the coordinates of each base station can be known in advance at the installation stage, the base station apparatus can transmit the location information necessary for positioning based on this. The base station is a base station of a cellular mobile telephone system or a personal mobile communication system installed on the ground. Standard macrocell base stations with cell radius of several kilometers or more, with the exception of small picocell base stations or microcell base stations with cell radius within a few hundred meters, have not only a sufficiently stable reference time, but also through cell planning from the installation stage. Since the location of the base station is selected, it is possible to sufficiently understand its location. If it is possible to transmit the position and time related information in any way, each mobile user can determine their position by the above-described triangulation principle. Most base station systems broadcast time-related information, so information to be broadcasted additionally is about location. Since the base station on the ground can receive a much stronger signal than the satellite, it is possible to overcome the effects of any obstacles, as well as the location information source is fixed, there is no need to track this in time.

FIG. 3 is an exemplary diagram of information carried on any base station in FIG. 2 and a wireless channel of the base station. The information of the traffic channel CHt is voice or data information used in both directions between any of the base stations BS1, BS2, BS3 and the terminal MS. The location information IMF of its own (base station) can normally be delivered using a call channel or a synchronization channel. The information of the pilot channel CHp is information transmitted only from the base stations BS1, BS2, BS3 toward the terminal MS, and used for synchronization acquisition of the terminal. This pilot information is a pseudo noise code of a certain length. The same code is shifted by a predetermined length unit (for example, 64) and used by different base stations. If the length of the pseudo-noise code is 32,768 bits and the mobile unit is 64 bits, the quotient of 32,768 divided by 64, that is, 512 different base stations can use the same code. The user terminal MS may estimate its current location based on the relative time difference between the location information and the pilot information. After all, the time difference is 'relative distance difference x luminous flux'.

4 is a structural diagram of a pilot channel. If the total length of the pseudo-noise code is k and the width of each offset is f, it can have a total of 'N = k / f' offset codes. Typically, pilot information is transmitted at a chip rate. That is, when the chip rate is Rc (or Tc: chip interval), the PN code is repeatedly transmitted by 'Rc / k' per second.

FIG. 5 shows a structure of a pilot channel when three base stations BS1, BS2, and BS3 are broadcasted with pseudonoise codes PN1, PN2, and PN3, each having a predetermined offset difference. If the terminal MS is equidistant from the three base stations BS1, BS2, and BS3, the terminal MS receives the offset pseudonoise codes PN1, PN2, and PN3 with exact timings, as shown.

FIG. 6 is a timing diagram illustrating a degree (time difference) in which each pilot channel information of FIG. 5 has a propagation delay according to a difference in distance. As shown in FIG. 2, if the MS is located at a different distance from each of the BSs BS1, BS2, and BS3, the received pilot channel information shows a time difference as much as the propagation region according to the difference in distance as shown. And pseudo-noise codes PN1 ', PN2', and PN3 'having a timing misalignment. Therefore, when the distance from the second base station BS2 is far from the base station BS1, the pseudo noise code PN2 'actually received from the second base station BS2 is the original pseudo noise code PN2. The delayed form by T2 is shown. Similarly, when referring to the first base station BS1, if the distance from the third base station BS3 is shorter, the pseudo noise code PN3 'actually received from the third base station BS3 is the original pseudo noise. It is shown that ΔT3 has been advanced from the code PN3. In conclusion, the current position can be estimated by finding the trajectories having the same time delay by finding the time of ΔT2 and ΔT3 and finding the point where the two trajectories meet. The accuracy of the position depends on the resolution that distinguishes the time difference. In other words, since a rake receiver is generally used as a receiver of the DS-CDMA system, the maximum error is determined by the resolution (R) of the rake receiver. In other words, the rake receiver is capable of decomposing and processing the received signal in units of one chip (a unit of time dividing one information bit into a DS-CDMA scheme, which is usually about several hundreds of chips per bit). The accuracy of the measurement is that when the coordinate information of the base station is correct, the error (R) becomes 'beam X Tc' and has an error of about 300 meters at 1M chip / sec. Therefore, the higher the chip rate of the broadband system, the smaller the error in distance. The rake receiver has several branch (three or more) receiver circuits. Each branch receiving circuit is for distinguishing signals of multiple paths having a time difference. Therefore, as in the present invention, it can be applied without modification to process pseudonoise codes from several places at the same time, which is similar to the principle used for soft handover processing. As the number of rake receivers in the terminal increases, the signal can be received from a plurality of adjacent base stations. Thus, by receiving a signal from a large number of base stations, it is possible to receive a lot of information for position calculation, thereby improving the accuracy of the position calculation.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by the equivalents of the claims.

First, by receiving the reference position and time signal from the base station of the cellular mobile phone system or personal mobile communication system installed on the ground, it can receive a much stronger signal than the satellite, so that the effects of any obstacles can be overcome, and the location information source is fixed. There is an advantage that it does not need to track this in time.

Secondly, since the base station using the DS-CDMA method needs to broadcast the location information using the call channel or the synchronization channel of the base station, there is almost no additional burden except for simply adding a message.

Third, the accuracy of the position measurement is increased by using the rake receiver in the DS-CDMA mobile communication system, and since the rate receiver has three or more branches, the software can accommodate this function without changing the hardware of the existing terminal. Larger numbers can reduce the error by accepting and processing signals from more base stations.

Fourth, it is possible to easily implement a positioning system having a position error of several hundred meters by adding some software without modifying the hardware of the existing DS-CDMA base stations and terminals.

Claims (5)

In the automatic positioning system, A plurality of mobile communication base station apparatuses for transmitting location information and time signals; Comparing the time signals received from each of the plurality of base station apparatuses with preset reference time signals, respectively, and calculating a difference in reception time. An automatic positioning system comprising a mobile communication terminal for estimating the position. The method of claim 1, The base station apparatus uses a direct spread-code division multiple access scheme, and transmits the location information through a call channel. The method of claim 1, The base station apparatus uses a direct spread-code division multiple access scheme, and transmits the location information through a synchronization channel. The method of claim 1, The base station apparatus transmits pilot channel information necessary for synchronization acquisition of the terminal, and the pilot channel information is generated as a pseudo noise code used by each of the plurality of base stations by shifting the same code by a predetermined length unit. Automatic positioning system. A positioning method of estimating a current position by a mobile communication terminal communicating with an adjacent first to third mobile communication base station apparatus, Receiving first-third pilot channel information from the first-third mobile communication base station apparatus; The second mobile communication base station apparatus and the third mobile communication base station apparatus for the first mobile communication base station apparatus by comparing the pilot channel information of the second and third mobile communication base station apparatus based on the pilot channel information of the first mobile communication base station apparatus Detecting a propagation delay time for each of the mobile communication base station apparatuses; And estimating a current position of the mobile station by finding a trajectory having the same propagation delay times and finding a point where the two trajectories meet for each of the second and third mobile communication base station apparatuses.

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