KR20030031711A - Position determining apparatus for mobile phone and the method - Google Patents

Abstract

PURPOSE: An apparatus and a method for determining a position of a mobile terminal are provided to accurately detect a position of a terminal inside a building or in a building-congested area. CONSTITUTION: Some of FAs(Frequency Allocation) of each base station are designated and only pilot signals of them are amplified in order to make all the pilot signals transmitted from each base station overlap with each other(S1). A terminal continuously checks the designated FAs, of which the pilot signals have been amplified, at pre-set time intervals(S2). The terminal stores information on the signal size of a pilot channel, signal transmission delay and the like in a memory and updates it(S3). When one button of the terminal is depressed(S4), the required information is transferred to a position determining server(S5). The position determining server determines a position of the terminal on the basis of the position-related information(S6).

Description

Positioning apparatus for mobile terminal and its method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning device and method for a wireless communication terminal, i.e., a portable telephone, and more particularly, to a positioning device for a terminal in a CDMA environment including IS95A & B, CDMA2000, and W-CDMA.

Recently, a lot of researches have been conducted on a positioning device and method of a terminal for allowing a terminal user to send a rescue signal with a single button and to identify the location of the terminal that has sent the rescue signal. There is a problem that it does not, or the accuracy is below the expected level.

One of them, Korean Patent Publication No. 2001-64729, filed by Korea Telecom, proposes a method for this, which receives at least three pilot signals around the terminal and estimates the difference in arrival time for the terminal. The concept is to determine the location of.

However, such a scheme is only proposed, and specifically, for example, what configuration a 'offline DLL (Delay Lock Loop)' for acquiring three or more forward pilot channels, which is the most important part of the present invention configuration, should have. In addition, there is a problem in implementation because it is not presented how to accurately obtain a pilot channel of another base station with a small reception power, and in order to implement the present invention, it is necessary to change the inside of the terminal modem or add a separate device to the terminal. In addition to the technical and economic difficulties, it is very difficult to apply it to actual products because no measures for increasing power consumption, which is one of the most important parts of the terminal design, are presented.

Apart from the above invention, the method of simply amplifying the signal size of the pilot channel transmitted from each base station so that the terminal acquires three or more pilot channels is obvious because it causes interference by the pilot signal in the terminal, resulting in poor communication. It is practically impossible to use.

On the other hand, although the method of tracking the location of the terminal using the Global Positioning System (GPS) has been proposed, the GPS can be applied in the outdoors, and in the downtown area where the majority of the population is concentrated, multipath between buildings is used. Due to the fading (fading) problem, its accuracy is reduced, and it is known that it is impossible to use due to its fundamental limitations inside the building. As a method to reduce the location tracking error of the method using GPS, there is a DGPS (Differential GPS) method that supplements the information obtained from a mobile GPS receiver by using information obtained by installing a GPS receiver at a point where the position is accurately known. In order to apply this method for location tracking, it is necessary to install a separate expensive fixed point GPS receiver.

The present invention has been made to solve the problems of the prior art as described above, an object of the present invention is to provide an apparatus and method that can more accurately determine the position of the terminal.

Other objects and advantages of the present invention will be understood through the embodiments described later.

1 is a schematic diagram of a terminal positioning system according to an embodiment of the present invention;

2 is a flowchart illustrating a terminal positioning method according to an embodiment of the present invention.

(Short description of symbols for main parts of drawing)

12: base station 14: positioning server

15: Base station GPS database

17: Geographic Information Database

100: terminal

104: Fast Lock Synthesizer (FLS)

The present invention to achieve the above object

Among the frequency allocation (FA) of each base station, among the Walsh code channels of the designated FA, it refers to a pilot channel in IS95A & B and CDMA2000 and a primary synchronization channel in W-CDMA. Amplifies signal components of a channel, a secondary synchronization channel, and a broadcasting channel) so that at least three system synchronization channel information can be transmitted to one terminal. It is possible to build a geographic information database based on the signal size, signal propagation delay information of the FA system synchronization channel, and accurate location information of the region, and to accurately locate the current base stations and the real-time location information received by the GPS receiver of the base station. Based on the base station GPS database to accumulate. According to the present invention, a terminal communicating or waiting in another FA accesses a designated FA according to a specified time interval, checks and stores three or more system synchronous channel signal sizes and signal propagation delays, and then needs a terminal user or a base station. For example, when the system synchronization channel information for the present time and the past time is transmitted to the base station, the position of the terminal having the highest correlation is compared to the geographic information database stored in the server connected to the base station. To figure out. In this case, if the GPS (Global Positioning System) reception function is built in the terminal, if the GPS signal information extracted from the terminal is sent together with the system synchronization channel information for the designated FA, the base station GPS database in the base station server can be used. Highly accurate terminal location tracking information can be obtained.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exemplary configuration diagram of a service system according to the present invention, and has the same configuration as a normal CDMA environment. That is, a plurality of base stations 12 are scattered, and the portable terminal 100 can communicate with the terminal which is synchronized with the other base station 12 through the base station 12, and controls the base station between them. The station 13 exists. In the present invention, the positioning server 14, the geographical information database unit 17, and the base station GPS database 15 are additionally provided so that the position information can be known. In addition, the terminal according to the present invention essentially has a fast lock synthesizer (FLS) 104 in addition to the communication unit 101 and the control unit 102, which are necessary for communication, and has a location information storage unit 103 added thereto. The geographic information database 17 and the base station GPS database 15 connected with the positioning server 14 will be described with reference to FIG. 2.

The configuration of the present invention is applicable to both the location tracking of IS95A & B and CDMA2000 based mobile communication terminals and the location tracking of W-CDMA based mobile communication terminals. However, since there is a lot of trouble in explaining the contents of the present invention due to the difference in the configuration of the two systems, in order to avoid this, first, the location tracking device and method of the IS95A & B, CDMA2000-based mobile communication terminal will be described first, and finally W-CDMA-based mobile An apparatus and method for tracking a location of a communication terminal is briefly described in comparison with that based on IS95A & B and CDMA2000.

First of all, the newly introduced Inter-Frequency Hard Handoff (IFHHO) function under the CDMA2000 environment will be described first in order to help understand the role of FLS, which is one of the important components of the present invention. One of the differences between the CDMA2000 environment and the existing IS95A & B-based CDMA environment is that, when the terminal moves past the area of the A base station with which the terminal was communicating to another B base station area, both base stations 12 under the existing IS95A & B-based CDMA environment. In the middle area of the CDMA2000 environment, there is only a soft handoff that is assigned a new Walsh code of the same frequency from the B base station and synchronizes with two base stations at the same time and moves the call base station to B without interruption of communication. In addition to the following, if base station B does not have a FA itself communicating with base station A, or if there is already a busy call and soft handoff is impossible, the base station and the terminal are interoperable with each other. Inter-frequency hard handoff that allows communication to continue by changing communication channels to the base station's FA (IFHHO: Inter Frequency Hard Handoff) has been added to facilitate FA resource utilization. This IFHHO is very important in the present invention will be described in more detail. IFHHO is adopted in the CDMA2000 environment to improve the efficiency of FA operation of base stations. If soft handoff is not easy when the mobile station moves from base station A to base station B, the existing IS95A & B-based CDMA terminal is disconnected. On the other hand, the CDMA2000-based terminal uses the IFHHO function to enable continuous communication by passing the communication channel normally without disconnection to another FA of the B base station. The CDMA2000-based terminal needs to monitor any FA promised with the B base station to perform the IFHHO function. That is, after receiving an arbitrary FA signal within a few ms before receiving an arbitrary FA from the B base station, it checks the pilot channel energy of the FA and checks whether the terminal can transfer to the FA of the B base station and make a call. You need to judge. In order to realize IFHHO without affecting the current call state, the CDMA200-based terminal should adopt FLS (Fast Lock Synthesizer). FLS refers to a frequency synthesizer that has a short time for the frequency to stabilize (called 'Lock Time') when the receiver of the terminal transitions from one FA to another FA. In CDMA2000-based terminals, the settling time is approximately 500 microseconds. It is enough. In the case of IS95A & B and CDMA2000-based communication with 20ms as the basic data frame when the frequency transition from αFA to βFA is checked and the frequency shift to αFA is less than 5 ms, the terminal is only 5 ms out of one frame. You will lose your data. The terminal perceives this loss of data as normal deep fading and can recover from the coding gain and error correction algorithms of current IS95A & B and CDMA2000-based terminal modems to a perfect frame. Therefore, even if the terminal monitors another FA for several ms during communication to perform IFHHO operation, the frame of the received data can be recovered without being damaged, so that the user does not feel it.

Next, look at the configuration of the IS95A & B and CDMA2000 base station more, first, each base station usually has a number of frequency assignments of several to several dozen, dozens of terminals can communicate at the same time in each frequency assignment. The number of frequency assignments for each base station shall be determined in accordance with the design of the telecommunications area within the frequency bands allocated by the telecommunications company by the contract with the government. Each frequency assignment also has 64 Walsh Code channels from w0 to w63, where w0 is a pilot channel. The pilot channel is a synchronization signal, which is a channel linked with GPS, and a signal for distinguishing each base station. When a terminal receives a specific FA signal, the first approach is the pilot channel and synchronization with the base station is made according to the signal of the pilot channel. When the power is turned on, all terminals attempt to receive a specific FA signal called a primary channel, and if this fails, try to receive a specific FA signal called a secondary channel. That is, every base station must have at least one of a primary channel and a secondary channel. Once the terminal has synchronized and communicated with either the Primary or Secondary channel and received certain information from the base station, each terminal then received the designated FA signal according to the prescribed rules to synchronize. From this point on, the terminal will be in a callable state.

Meanwhile, reference numerals 105, 15, 17, and 120 will be described with reference to FIG.

2 is a flowchart illustrating an embodiment of a terminal positioning method according to the present invention.

First, in the exemplary embodiment of the present invention, a few of the plurality of FAs of each base station are designated to amplify only pilot signals of the FAs so that all pilot signals transmitted from each base station overlap (S1). Corresponds to a pilot channel in IS95A & B and CDMA2000. Since the amplified and duplicated pilot signals may act as noise in a CDMA communication environment, the number of designated FAs is preferably one so that terminals in other FAs can communicate without being exposed to unnecessary noise and amplify only pilot signals. It will be advantageous to minimize the additional S / W burden on additional equipment and terminals by allowing the FA to be either the primary channel or the secondary channel that the base station always has. In addition, in the frequency allocation, the base station preferably changes the frequency allocation logic so that communication is performed at other FAs except for the FA designated above, and in the designated FA, the base station may consider the noise level received from the terminal. You need to adjust the number.

At the designated time interval, the terminal continuously checks the designated FA whose pilot signal is amplified among the FAs of the base station. (S2) At this time, the designated time interval is set to, for example, a slotted index value between the base station and the terminal. It is preferable to interlock accordingly. The slotted index is determined by the base station to the terminal, and the terminal checks the base station at a predetermined time interval in the standby mode, wherein the time interval is It is set in seconds, where i is the slotted index. When the terminal is in the standby mode, it checks the signal coming from the base station to check whether there is a message to be sent to the terminal such as a call, text message, voice message from another person, or the system parameter that the terminal is talking on. It checks whether or not, and informs the base station of the terminal if necessary. In this case, according to the present invention, for example, when the terminal is in the standby mode by using the FLS built in the terminal, the terminal is not assigned to the FA for a few ms (for example, 5 ms) before or after a designated time for monitoring the base station signal. At S1, the designated FA where the pilot channel energy is increased is checked for terminal location tracking. Even if the terminal is in the call mode, as described above, other FAs can be checked without compromising the quality of the call.

As set in step S1, since a pilot signal transmitted from at least three base stations is set to overlap all regions, the terminal always checks pilot signals of three or more FAs. CDMA-based terminals can calculate their own information about the pilot channel's signal size and signal propagation delay, which can be distance information from each base station. The terminal stores this information in the memory of the terminal and updates it (S3).

The updated information may be stored in the positioning server through one main station and a control station which synchronize with the corresponding terminal at arbitrary time intervals. The time interval at which the terminal sends information to the server may be adjusted according to the demand for the location information of the terminal. For example, when one button of the terminal is pressed (S4), as requested by E911 (Enhanced 911). Only necessary information may be sent to the positioning server (S5).

The location server determines the location based on the location related information received from the terminal (S6). At this time, in the present invention, the pilot channel signal size for the designated FA, in which the pilot channel signal size is amplified for location tracking, One requirement may be a configuration of a geographic information database (17 in FIG. 1) based on signal propagation delay and accurate location information of the region. In urban environments with high-rise buildings, there is almost no line-of-sight between the base station and the terminal. Therefore, the mobile communication signal from the base station reaches the terminal through electromagnetic wave reflection and diffraction of various paths. do. Therefore, if the location of the terminal is tracked using only the numerical model using only the signal size and signal propagation delay time of the pilot channel reaching the terminal, it has a very large distance error. In order to overcome this difficulty, the location of the terminal is most correlated with the information received from the terminal using a geographic information database on the pilot channel signal size and signal transmission time delay for the designated FA. Estimate with will be the closest location tracking method.

Qualcomm, which manufactures and supplies CDMA terminal modem chips almost exclusively, has a GPS core embedded in the modem chip.The GPS chip antenna for development, which is currently being developed and commercialized, is widely installed in the terminal. Will be used. As such, when the GPS engine inside the terminal modem chip is used or a separate dedicated GPS module is attached to the terminal to receive the GPS signal smoothly on the terminal itself, the terminal is assigned to the designated FA obtained by the method proposed in the present invention. The GPS signal data obtained by the terminal itself can be informed to the base station when necessary along with information about the signal size and signal propagation delay of the pilot channel.

At this time, the present invention is a requirement for the configuration of the base station GPS database (15 in Fig. 1) to continuously update the location information received from the GPS receiver of each base station with accurate location information for each of the current base stations for location tracking You can do The GPS signal coming down from the GPS satellite has a slight error even when the signal is received at a fixed position according to the thickness of the ionosphere and weather conditions. In this case, if the position of the base station is known correctly, the error of the GPS signal received by the base station GPS receiver (120 of FIG. 1) can be accurately known, and it can be assumed that the transmission environment of the GPS signal around the base station is almost similar. Therefore, it is possible to accurately correct the error of the GPS signal received by the mobile GPS receiver (105 in FIG. 1) around the base station. In this way, the positioning server uses the base station GPS database (15 in FIG. 1) and the geographic information database (17 in FIG. 1) having the exact location information of the region. Very accurate location tracking is possible from the information and GPS signal information.

This method can be regarded as a type of so-called DGPS (Differential GPS), but using a CDMA base station already operating based on a GPS signal as a GPS receiver instead of separately installing a GPS receiver that knows a precise location. Can be. It is well known that the use of DGPS increases the accuracy of location tracking, compared to tracking locations using only GPS signals. In open areas as well as in multi-city fading environments in multi-path fading environments, the effect of this DGPS method is certainly very significant, and even in areas where the GPS signal itself cannot be received, such as in a building. The effect of the present invention is apparent in that position tracking is possible even in.

In the case of W-CDMA, the location of the mobile terminal can be tracked in the same manner as described above using FLS, but there are some differences in the specific embodiments due to differences in operation of the W-CDMA system and the operation of the IS95A & B and CDMA2000 systems. Is. In the IS95A & B and CDMA2000 systems, the system synchronization channel of FIG. 2 is one as a pilot channel, but in a W-CDMA system, a primary synchronization channel (Primary-SCH) and a secondary synchronization channel (hereinafter, Secondary-) are used. SCH) and broadcasting channel. In the Primary-SCH, all the base stations are the same, and from the terminal's point of view, only the signal transmission delay information between each base station and the terminal can be obtained, and the Secondary-SCH has base station group information. Identification information is available. That is, the role of one pilot channel of IS95A & B and CDMA2000 is divided into primary-SCH, secondary-SCH, and broadcast channel in W-CDMA, but there is no fundamental change in the basic concept for implementing the configuration of the present invention.

Although the W-CDMA terminal monitors the base station at predetermined time intervals from the base station in the standby mode, the W-CDMA terminal is no different from the terminal based on the IS95A & B and CDMA2000, but the period and terminology are different. However, there is no difference in the basic concept in the context of the present invention.

One of the fundamental differences between W-CDMA and existing IS95A & B and CDMA2000 systems is that they are not GPS-based. Therefore, a big difference is that real-time GPS information at the base station location updated in real time to the base station GPS database proposed in the present invention is possible only by installing an additional GPS receiver.

As described above, the present invention has the advantage that the location of the terminal, which has been felt almost impossible in the conventional building dense area or inside the building, is made.

In addition, there is an advantage that it is possible to efficiently locate the terminal without large modifications to the existing communication system.

Although the preferred embodiment according to the present invention has been described above, this is merely an example, and the scope of the present invention is not limited thereto, and various changes and modifications may be made according to the spirit of the present invention. It will be recognized by the appended claims that they belong.

Claims (7)

As a device for identifying the location of a wireless terminal, Each of which communicates with the terminal, has a plurality of frequency assignments (FAs), and amplifies at least one system synchronization channel signal of the specified frequency assignment, thereby allowing the terminal to detect at least three system synchronization channel signals; Base stations; A communication unit for communicating in synchronization with one of the plurality of base stations, and an FLS for checking at least three system synchronization channel signals transmitted from the plurality of base stations at regular intervals in a frequency allocation in which the system synchronization channel signals are amplified; A terminal having a Fast Lock Synthesizer, a control unit for controlling the communication unit and the FLS, and a memory for storing information of the three or more system synchronous channel signals; Positioning server for receiving the three or more system synchronous channel signal information stored in the terminal through the base station to determine the position of the terminal Positioning device of the wireless terminal comprising a The method of claim 1, The base station and the terminal includes a receiver for receiving a GPS signal, The positioning server corrects an error of a GPS signal measured by a terminal equipped with the GPS receiver and a geographic information database based on the system synchronization channel signal size of the designated FA, signal transmission delay, and accurate location information of the region. A positioning device of a wireless terminal having a base station GPS database for accumulating accurate position information of current base stations and position information received by a GPS receiver of the base station. The method of claim 1, The positioning device of the radio terminal according to the fast lock synthesizer (FLS) to check the designated FA of the plurality of base stations according to the slotted index The method of claim 1, A terminal for synchronizing with the base station is a positioning device of a radio terminal in which the frequency allocation is designed so that a relatively large number of communication is performed in a FA other than the designated FA. The method of claim 1, The terminal is a positioning device of a wireless terminal to send a plurality of pilot signal information stored in the memory to the positioning server through the base station when there is a specific signal input A plurality of base stations each having a plurality of frequency allocations (FAs); A terminal having a communication unit, a fast lock synthesizer (FLS) for checking one frequency allocation and another frequency allocation during synchronization, a control unit for controlling the communication unit and the FLS, and a memory; A method of determining the position of the terminal in a wireless communication system including a positioning server, Amplifying a system synchronous channel signal by designating at least one of a plurality of frequency allocations of each base station to allow one terminal to receive at least three system synchronous channel signals; Checking, by the terminal synchronized with one of the base stations, the plurality of system synchronization channel signals by periodically checking the designated frequency allocation of the base stations using FLS; Storing the identified plurality of system synchronous channel signal information in a memory of the terminal; Sending the stored system synchronization channel signal information to the positioning server; Determining, by the positioning server, the location of the terminal based on the system synchronous channel signal information; Positioning method of the terminal comprising a The method of claim 6, Receiving GPS information at the terminal and sending the GPS information to the positioning server; And receiving GPS information from the base station and sending the GPS information to the positioning server. In the step of determining the location of the terminal, the positioning method of the terminal using the GPS reception information of the terminal, the geographic information of each base station and the real-time GPS reception information of each base station as correction data