KR100933165B1 - Information measuring device and method for providing location service in asynchronous mobile communication system - Google Patents

Abstract

The present invention relates to a mobile communication system supporting a location service, and more particularly, to an information measuring apparatus and method for providing a location service in an asynchronous mobile communication system, comprising: receiving and subdividing a frequency clock from a GPS satellite to generate GPS timing; ; Generating a system frame number frame in synchronization with a system frame number frame generated by the modem of the base station by using the system clock received from the clock generation board of the base station; Counting GPS timings received from the GPS module and converting them to absolute time; Measuring a transmission time of a common pilot channel having the generated system frame number frame using the absolute time; And transmitting the absolute time information of the measured transmission time to a base station mainboard. The method and apparatus for providing location service in an asynchronous mobile communication system are provided.

Description

Information measuring apparatus and method for providing location service in asynchronous mobile communication system {APPARATUS AND METHOD FOR MEASURING INFORMATION TO SUPPORT LOCATION SERVICE IN UNIVERSAL MOBILE TELECOMMUNICATION SYSTEM}

1 is a view showing the basic concept of a network-based position measuring apparatus to which the present invention is applied,

2 is a block diagram showing a base station according to an embodiment of the present invention;

3 is a block diagram showing a position measuring apparatus according to a preferred embodiment of the present invention,

4 is a view showing the generation of SFN frame in the position measuring apparatus according to an embodiment of the present invention,

5 is a diagram illustrating a timing relationship between an absolute GPS timing absolute time and a CPICH frame according to an exemplary embodiment of the present invention.

The present invention relates to a mobile communication system supporting location services, and more particularly, to an information measuring apparatus and method for providing location services in an asynchronous mobile communication system.

In general, the method used to detect the position of a mobile terminal in a mobile communication system includes a cell-id (CELL-ID) method, an angle of arrival (AOA) method, a time of arrival (TOA), and an arrival delay. It can be classified into four methods: a time difference of arrival (TDOA) method and a global positioning system (GPS) satellite method.

First, the cell-ID method is a method of determining the location of a mobile terminal existing in the cell with the location information of the base station while having accurate location information of the base station in charge of each cell.

Next, the arrival angle (AOA) method is a method of knowing the position of the mobile terminal when the angle of the base station and the mobile terminal is known using an intelligent antenna such as a smart antenna.

The arrival time (TOA) method is a method of detecting the position of a mobile terminal with a difference between the time that a signal is transmitted from the base station and the arrival time of the signal, and the arrival delay time (TDOA) method is at least three base stations Is a method of detecting the position of the mobile terminal using the same method as the triangular positioning method transmitted to the mobile terminal.

Finally, the method of using GPS satellite signals is a method of identifying the location of a mobile terminal using the signals received from GPS satellites.

Currently, the mobile communication system measures the position of the mobile terminal by selecting a combination of the four position measuring methods or one of the four methods. In particular, the method of using the GPS satellite signal is increasing in use because it provides an accurate absolute position for the mobile terminal using the signal provided from the GPS satellite.

However, the method of using the GPS satellite signal has a problem that the position of the mobile terminal cannot be measured because the satellite signal does not reach a shaded area such as an underpass. In addition, the cell-ID method has a problem that the location of the mobile terminal is incorrect because the location of the mobile terminal is determined in units of base station cells. In addition, the arrival angle method has a problem that it is impossible to accurately determine the location of the mobile terminal if the transmission angle cannot be determined. In addition, the arrival time and arrival delay time method has a problem that it is not possible to determine the exact position of the mobile terminal due to the position error factors such as the deflection and diffraction of the signal in an environment in which obstacles such as high-rise buildings are concentrated. In addition, since the synchronous mobile communication system synchronizes the base station using a GPS satellite receiver, a position measuring device is not required in hardware, but an asynchronous mobile communication system is required.

Accordingly, an object of the present invention is to provide an apparatus and method for measuring information necessary for providing a location service of a mobile terminal in an asynchronous mobile communication system.

Another object of the present invention is to provide an apparatus and method for increasing the accuracy of measured information by measuring a transmission time of a common pilot channel using GPS timing.

An information measuring apparatus for providing a location service in an asynchronous mobile communication system according to the present invention for achieving the above object, comprising: a module for generating GPS timing by subdividing a frequency clock received from a GPS satellite; Using the system clock received from the clock generation board of the base station, a system frame number frame is generated which is synchronized with the system frame number frame generated by the modem of the base station, and counts the GPS timing received from the GPS module. A clock comparator, which converts time to a time, measures a transmission time of a common pilot channel having the generated system frame number frame using the absolute time, and transmits absolute time information of the measured transmission time to a controller; And the controller which transmits the absolute time information received from the clock comparator to a base station main board.

In addition, an information measuring method for providing a location service in an asynchronous mobile communication system according to the present invention for achieving the above object, comprising the steps of: receiving and subdividing a frequency clock from a GPS satellite to generate GPS timing; Generating a system frame number frame in synchronization with a system frame number frame generated by the modem of the base station by using the system clock received from the clock generation board of the base station; Counting GPS timings received from the GPS module and converting them to absolute time; Measuring a transmission time of a common pilot channel having the generated system frame number frame using the absolute time; And transmitting the absolute time information of the measured transmission time to a base station main board.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, specific features appear in the following description, which is provided to help a more general understanding of the present invention, and the present invention may be practiced without these specific matters to those skilled in the art. It will be self explanatory. In the following description of the present invention, detailed descriptions of related well-known functions or configurations will be omitted when it is determined that the detailed descriptions may unnecessarily obscure the subject matter of the present invention.
In the third generation asynchronous mobile communication system to which the information measuring device for providing a location service of a mobile terminal is applied in the asynchronous mobile communication system according to the present invention, an algorithm for calculating a position is referred to as an Observed Time Difference of Arrival (hereinafter referred to as "OTDOA"). And network-assisted GPS (hereinafter referred to as "A-GPS").

Information required for providing location services in an asynchronous mobile communication system is absolute time (AT) and relative time difference (RTD), and the position of the mobile terminal is calculated using the above information. In the present invention, the difference between the absolute time and the relative time is calculated based on the transmission time of the common pilot channel frame (hereinafter referred to as "CPICH"). Accordingly, the position measuring device according to the present invention reads the transmission time of the CPICH frame as an absolute time using the GPS module.

Hereinafter, with reference to Figure 1 will be described the basic concept of the position measuring apparatus to which the present invention is applied.
1 is a diagram illustrating a basic concept of a network-based location measuring apparatus to which the present invention is applied. As shown in FIG. 1, a mobile terminal that wants to receive location services using an arrival delay time method observed in an asynchronous mobile communication system receives at least three or more base station signals, and receives a relative of three or more base station signals. The reason why the mobile terminal should receive at least three base station signals is to measure the position of the mobile terminal using the triangulation principle using the relative time difference information. Since the OTDOA method uses a base station frequency, the position of the mobile terminal can be obtained continuously in the call area of the mobile terminal.

The synchronous mobile communication system does not need to measure the information of the relative time difference 104 because the synchronization between the base stations is consistent with the GPS, but the asynchronous mobile communication system is a subordinate synchronization that synchronizes the synchronization from the network. Do not. Therefore, in order to obtain the relative time difference RTD 104, it is necessary to know the time of the other base stations 105 and 107 based on one base station 103. In this case, the reference time is the CPICH frame transmission time of the base station 103 and the CPICH frame transmission time of the other base stations 105 and 107, and the relative time difference 104 can be known through the CPICH frame transmission time.

In the asynchronous mobile communication system, the clock of the base station operates as a base station frame number (BFN) counter having a 10 ms period and a 4096 chip range, and has a difference of chip offset (T_cell) for each sector. . The difference between the chip offsets is called a system frame number ("SFN") counter. In addition, the SFN has the same period and range as the BFN.

Accordingly, the present invention measures the absolute time (GPS timing measurement) 102 using the GPS timing 101 to obtain the transmission time of the CPICH frame having the SFN of 10 ms period in each sector. Here, it is assumed that the position measuring device 211 is a time when a CPICH frame is transmitted for each SFN frame.

2 is a block diagram illustrating a base station according to a preferred embodiment of the present invention. Hereinafter, the internal configuration and operation of the base station according to the preferred embodiment of the present invention will be described in detail with reference to FIG. 2. Referring to FIG. 2, in the asynchronous system, the network synchronizer uses a slave clock distributed from a core network. In the core network, synchronization between the base station controller (RNC) 201 uses STM-1, and the clock is adjusted using the E1 / T1 interface between the base station controller 201 and the base station 213. The base station 213 distributes the clock to all the boards that are matched to the base station through the clock generation board 203, the dependent clock obtained from the E1 / T1 interface.

The modem MODEM 205 transmits a CPICH frame having a SFN of 10 ms period to the radio section by using the clock distributed through the clock generation board 203. At this time, it is necessary to find out the transmission time of the CPICH frame transmitted to the radio section.

The clock generation board 203 distributes the clock to all boards matched to the base station 213 such as the modem 205 and the position measuring device 211. The clocks distributed to the modem 205 and the position measuring device 211 should be synchronized with each other. However, due to factors such as line length or processor delay, accurate synchronization cannot be achieved. However, if the factors are known in advance, synchronization can be achieved. Further, in the position measuring device 211 of the present invention, even if the synchronization is not correct, it does not matter much.

Since the position measuring apparatus 211 uses a relative time difference of the OTDOA method, if the other base station also has a time delay environment due to the above factors, it can eliminate the delay time. That is, if the time measured by one base station is T1 + α1 and the time measured by the other base station is T2 + α2, and α1 and α2 are errors of the line length or processor delay time common to each base station, T1 + Since T2 + (? 1-? 2), the common error portion is almost canceled out.

The positioning device 211 receives chip offset (T_cell) information from a Node B Application (NBAP) protocol when the initial positioning device is set, and the base station main board 209 equipped with the NBAP protocol is measured information. To pass. The base station main board 209 encodes the information received from the location measuring device 211 into a message and transmits the information to the higher location service server. Here, the information received by the base station main board 209 from the position measuring device 211 is information required for measuring the position of the mobile terminal in the OTDOA method, and means an absolute time.

3 is a configuration diagram showing a position measuring apparatus according to a preferred embodiment of the present invention, with reference to Figure 3 below will be described in detail the internal configuration and operation of the position measuring apparatus according to a preferred embodiment of the present invention. Referring to FIG. 3, the position measuring device 211 includes a clock receiver 301, a clock comparator 303, a controller 307, an interface 311, an alarm 309, and a GPS module 305. It is composed. In particular, the GPS module 305 is a module that receives only GPS timing to measure absolute time. The clock receiver 301 receives the clock of the base station and transfers it to the clock comparator 303. The clock comparator 303 generates an SFN frame by using the clock of the base station received from the clock receiver 301, and starts the SFN frame with time information (GPS timing) output from the GPS module 305. Find out. A method of generating the SFN frame, the relationship between the SFN frame start point and the transmission time of the CPICH frame, and the GPS timing in absolute time will be described later with reference to FIGS. 4 and 5. The controller 307 is responsible for control and management functions, and transmits the measured information received from the clock comparator 303 to the base station main board 209 through the interface unit 311. When a problem occurs in the position measuring device 211, the alarm unit 309 transmits a signal indicating that a problem has occurred to the display unit 322.

4 is a view illustrating a SFN frame generation in a position measuring apparatus according to a preferred embodiment of the present invention. Referring to FIG. 4, the position measuring apparatus 211 and the clock comparing unit ( In step 303, the process of generating the SFN frame will be described in detail.

The position measuring device 211 generates a 10ms BFN frame by inputting a system dependent clock, and generates an SFN frame using chip offset (T_cell) information received from the NBAP protocol. Here, since the position measuring device 211 knows the chip offset (T_cell) information in advance for each sector, the system dependent clock (SYSTEM CLOCK 1) having a 10 ms dependent clock (SYSTEM CLOCK 2) and a period T nsec is used as an input. To create a BFN frame. If T nsec is eight (T_bit), one chip is T_chip, 256 chips are regarded as one symbol T_symbol, and ten symbols are one slot T_slot. That is, one slot is composed of 2560 chips. Therefore, the BFN consists of 15 slots, and can generate an SFN frame having a difference of the chip offset T_cell. The SFN frame of the position measuring device 211 and the SFN frame generated by the modem 205 are synchronized with each other.

Hereinafter, a process of converting GPS timing into absolute time will be described with reference to FIG. 5. 5 is a diagram illustrating a timing relationship between a GPS timing absolute time and a CPICH frame according to an exemplary embodiment of the present invention.

The clock comparator 303 which uses the frequency received from the GPS module 305 as a clock input counts a pulse and converts the pulse into an absolute time. The GPS timing is reset at 1PPS at the GPS Time of Week on Sunday 00:00:00 seconds. That is, the GPS TOW has 604800 seconds (7 days * 24 hours * 3600 seconds). In order to increase the measurement accuracy of the position measuring device 211, it is preferable to design the frequency transmitted from the GPS module 305 to N times higher than the chip ratio (3.84 Mcps) of the system.

The GPS module 305 generates a clock having T_g nsec obtained by subdividing GPS timing, and the clock comparator 303 counts a clock having T_g nsec and converts the clock into absolute time. Accordingly, the clock comparator 303 can know the transmission time of the CPICH frame transmitted every 10ms using the absolute time counted GPS timing. That is, the absolute time is measured using time information (GPS timing) based on the transmission time of the CPICH frame. The measured absolute time information is transmitted to the base station controller 201 and delivered to the processor managing the location service resource. Accordingly, the processor managing the location service resource may determine the relative time difference by comparing the measured absolute time information received from the location measuring device of the reference base station with the measured absolute time information received from the location measuring devices of other base stations.

As described above, in order to provide a location service in an asynchronous mobile communication system, a SMLC (Serving Mobile Location Center) according to the information measuring apparatus and method for providing a location service of a mobile terminal in an asynchronous mobile communication system according to the present invention The position of the mobile terminal can be accurately calculated using the absolute time and the relative time difference.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made 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 determined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, the method using the GPS satellite cannot measure the position of the mobile terminal in the shaded region where the satellite signal is cut off, whereas in the present invention, the position is also located in the shaded region where the satellite signal is cut off by using the position measuring device. There is an advantage that can accurately calculate the information for service provision. In addition, by measuring information for providing location services using GPS timing, there is an advantage that can increase the accuracy of the measured information.

Claims (12)

An information measuring apparatus for providing a location service in an asynchronous mobile communication system, A GPS module for generating GPS timing by subdividing a frequency clock received from a GPS (Global Position System) satellite; Using the system clock received from the clock generation board of the base station, a system frame number frame is generated which is synchronized with the system frame number frame generated by the modem of the base station, and counts the GPS timing received from the GPS module. A clock comparator, which converts time to a time, measures a transmission time of a common pilot channel having the generated system frame number frame using the absolute time, and transmits absolute time information of the measured transmission time to a controller; And And a control unit which transmits the absolute time information received from the clock comparator to a base station main board. An information measuring method for providing a location service in an asynchronous mobile communication system, Receiving and subdividing a frequency clock from a GPS satellite to generate GPS timing; Generating a system frame number frame in synchronization with a system frame number frame generated by the modem of the base station by using the system clock received from the clock generation board of the base station; Counting the generated GPS timing to convert it to absolute time; Measuring a transmission time of a common pilot channel having the generated system frame number frame using the absolute time; And And transmitting the absolute time information of the measured transmission time to a base station main board. The method of claim 1, wherein the GPS timing, And a frequency clock received from the GPS satellites to have a resolution N times higher than that of the received frequency clock to provide location service in an asynchronous mobile communication system. The method of claim 1, wherein the clock comparison unit, Asynchronously generating a base station frame number frame by receiving the system clock, receiving chip offset information from a Node B Application (NBAP) protocol, and generating the system frame number frame using the chip offset information Information measuring device for providing location services in a mobile communication system. The method of claim 2, wherein the GPS timing, And dividing the frequency clock received from the GPS satellites to have a resolution N times higher than that of the received frequency clock. The method of claim 2, wherein the generating of the system frame number frame comprises: A base station frame number frame is generated by receiving the system clock, chip offset information is received from an NBAP protocol, and the system frame number frame is generated using the chip offset information. How information is measured to provide services. A base station apparatus for measuring information for providing location service in an asynchronous mobile communication system, A modem for wirelessly transmitting a common pilot channel frame having a system frame number using a system clock distributed from a clock generation board that distributes clocks to all boards matched with the base station; A position measuring device for generating a system frame number frame in synchronization with a system frame number frame generated by the modem and calculating an absolute time using GPS timing received from a GPS satellite; And An information measuring base station apparatus for providing a location service in an asynchronous mobile communication system, comprising; a base station main board which transmits information on an absolute time calculated by the location measuring apparatus to a higher server. The method of claim 7, wherein the GPS timing, An information measuring base station apparatus for providing location services in an asynchronous mobile communication system, characterized in that the frequency clock received from the GPS satellites is divided into N times higher resolution than the received frequency clock. The method of claim 7, wherein the position measuring device, A base station frame number frame is generated by receiving the system clock, chip offset information is received from an NBAP protocol, and the system frame number frame is generated using the chip offset information. An information measuring base station apparatus for providing a service. A method for measuring information for providing location service in a base station of an asynchronous mobile communication system, Wirelessly transmitting a common pilot channel frame having a system frame number using a system clock distributed from a clock generation board that distributes clocks to all boards matched with the base station; Generating a system frame number frame in synchronization with the system frame number frame generated by the modem, and calculating an absolute time using GPS timing received from a GPS satellite; And And transmitting information about the calculated absolute time to an upper server. Information measuring method for providing a location service in an asynchronous mobile communication system. The method of claim 10, wherein the GPS timing, And dividing the frequency clock received from the GPS satellites to have a resolution N times higher than that of the received frequency clock. The method of claim 10, wherein the generating of the system frame number frame comprises: A base station frame number frame is generated by receiving the system clock, chip offset information is received from an NBAP protocol, and the system frame number frame is generated using the chip offset information. How information is measured to provide services.

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