KR20020002936A - Apparatus and method for location determination by single cell in mobile communication system - Google Patents

Abstract

PURPOSE: An apparatus for deciding a position of a terminal by using a single cell in a radio communication system and a method therefor are provided so that various position services such as a regional information service, a vehicle monitoring service and a mobile yellow page can be provided by measuring a position of a mobile station in a region of poor audition by using one base station. CONSTITUTION: A code obtaining and phase delay synchronizing unit(13) obtains an in-phase pseudo noise code of the first and second reception signals from a radio terminal(mobile station) through the first and second antennas(11)(12) of an identical base station, monitors the in-phase pseudo noise code, performs synchronization, and predicts a time of arrival. A reverse diffusion unit(14) respectively demodulates the first and second reception signals according to an in-phase carrier and an orthogonal phase carrier, and reversely diffuses the demodulated signals according to the in-phase pseudo noise code. An arrival angle measuring unit(15) calculates a phase mono pulse output value from the signals reversely diffused by the reverse diffusion unit(14), and measures an angle of arrival from the phase mono pulse output value. A position deciding unit(16) decides a position of the radio terminal on the basis of the time of arrival and the angle of arrival.

Description

Apparatus and method for location determination by single cell in mobile communication system}

The present invention is a wireless subscriber network (WLL), broadband wireless subscriber network (B-WLL), mobile telephone network (Cellullar), personal mobile communication network (PCS), intelligent transportation network (ITS), other mobile telephone networks in use abroad, Terminal location determination using a single cell in wireless communication systems including next generation mobile communication networks such as International Mobile Telecommunication-2000 (IMT-2000) and Universal Mobile Telecommunication Service (UMTS), which are currently being standardized in North American and European methods An apparatus, a method thereof, and a computer-readable recording medium having recorded thereon a program for realizing the method.

In general, the location determining technology may be classified into the following network-based, terminal-based, dedicated network-based, and other technologies.

Techniques for determining location will be described in more detail to aid in the understanding of the present invention.

First of all, the network-based technology is a method of determining a location using a base station constituting a mobile communication network. The necessary parameters are angle of arrival (AOA) and arrival time (TOA). Time of Arrival), Time Difference Of Arrival (TDOA), amplitude, phase, signal strength, etc. The calculation of the location of these parameters in the network side is called a network-based technology, and the parameters can be classified into a case of receiving at the base station and a method of receiving at the terminal and transferring them to the network side.

When using a network-based technology, the location can be determined without changing the existing terminal without additional equipment.

The Federal Communications Commission (FCC) mandate of the US states that by October 1, 2001, network-based technologies will be able to locate within a 100-meter radius for wireless E911 (Enhanced 911) services.

Next, referring to the terminal-based technology, it may be referred to as a technology based on the Global Positioning System (GPS). That is, a method of determining one's own location by using signal information of GPS satellites received by a GPS module built in a terminal, a method of determining one's own location by a GPS module, a terminal having a built-in GPS module, There is a method of determining the location by transmitting and receiving data with the network equipment that has information about the GPS satellites.

In case of using an external GPS, the cost of purchasing the GPS separately is increased, and the size of the terminal becomes large, making it difficult to carry.

On the other hand, when looking at the technology based on the dedicated network, which is a technology using a dedicated network for positioning, and uses a different frequency than the general wireless communication system. For example, a dedicated network in the US LMS (location and monitoring) band is used, and a separate signal is used for location determination. This is a kind of road sign, and roadside base stations of the Intelligent Transportation System (ITS) are included in this category.

Dedicated network-based technology generally lacks economic feasibility because a separate network must be constructed for location verification. On the other hand, high accuracy can be achieved if the signal is also designed for a specific application and installed in some areas.

In addition to the above-described method, there is a radio camera technology that determines a location by receiving a signal transmitted from a terminal in a network similar to the network-based technology.

RadioCamera technology finds a location by comparing the fingerprint of a wireless signal type with the current user's wireless signal type in advance. The technology uses a database of user signals received via multipath and radio signal propagation that is already established to enable continuous location measurements regardless of the user's own location requirements.

In addition, there is a method of identifying a location by an identifier (ID) of a base station or a sector in a base station area, although no special positioning technology is used. That is, it is possible to identify its own location by the sector ID in the base station or the base station area which is served by the digital cellular mobile communication system or the PCS system. However, since the size of a sector in a base station or a base station area in a cellular mobile communication system or a PCS varies, the accuracy with respect to the position also varies greatly.

Another method of classifying positioning techniques may be classified into a method using a forward link and a method using a reverse link according to a receiving direction of a signal required for positioning.

The forward link is a path through which a signal is transmitted from a base station to a terminal. At this time, a channel that can be used for positioning includes a pilot channel, a forward traffic channel, a synchronization channel, a calling channel, and the like, and positioning in a code division multiple access (CDMA) mobile communication network mainly uses a pilot channel.

The reverse link refers to the path from the terminal to the base station. At this time, a channel that can be used for positioning is a reverse traffic channel.

As described above, the dedicated network-based technology for the positioning technology is not economical in constructing a nationwide network because the separate network has to be constructed, and the RadioCamera technology is also affected by changes in the radio environment in areas such as Seoul, Korea. It is considered that there will be many problems in updating the propagation map database.

In general, the most widely used positioning technology is network-based or terminal-based technology, which determines the location based on three or more signals received from the terminal or the base station.

However, although the PUF (Power Up Function) has been proposed to improve the "Hearability" for the reverse link positioning that receives the signal from the base station, it is a universal positioning service because it can reduce the capacity of the system by increasing the interference of the entire network. It is not known to be a suitable way.

On the other hand, at least three signals must be received for forward positioning, but according to the results of published literature or measurements performed by the Korea Telecom on the forward pilot signal of the IS-95 network, an area that can receive more than three signals is Only a portion of the service area was surveyed. In particular, in view of the domestic reality, which uses a lot of repeaters to expand service coverage, the area where three or more signals are received is smaller than the service providing area. Various methods have been proposed to improve the forward Hearability problem, but it is analyzed that there is much need to be solved to provide positioning service anywhere in the country because it is difficult to obtain desired accuracy and reliability by applying it to the entire service area with one technology.

Therefore, in view of the reality that three or more signals are required for positioning but fail to satisfy them, a method of determining a location of a wireless terminal (mobile station) with only one base station is required.

Accordingly, the present invention has been proposed to meet the above requirements, and realizes a terminal positioning device using the single cell for determining the position of the wireless terminal with only one base station in the wireless communication system and the method and the method. The object of the present invention is to provide a computer-readable recording medium having recorded thereon a program.

1 is a block diagram of an embodiment of a terminal positioning device using a single cell according to the present invention.

2A and 2B are conceptual illustrations of magnitude monopulse and phase monopulse used in the present invention.

3 is an explanatory diagram showing a relationship between an antenna array and an incident angle of a signal used in the present invention;

4 is a detailed configuration diagram of an embodiment of a terminal positioning device using a single cell according to the present invention.

5 is an explanatory diagram showing a relationship between a phase mono pulse output value and an incident angle in an ideal channel used in the present invention.

6 is a flowchart illustrating a method for determining a terminal location using a single cell according to the present invention.

* Explanation of symbols for the main parts of the drawings

11,12 antenna 12 code acquisition and phase delay synchronizer

13: despreader 14: angle of arrival (AOA) estimator

15: positioning unit

In order to achieve the above object, the present invention provides an in-phase pseudo noise of a first and a second received signal received from a mobile station through a first and a second antenna in a same base station in a terminal position determining apparatus in a wireless communication system. Synchronization and arrival time predicting means for acquiring and tracking code to synchronize and predict the time of arrival (TOA); Despreading means for despreading the first and second received signals by in-phase carrier and quadrature carrier, respectively, and then despreading by the in-phase pseudo noise code; Arrival angle estimating means for obtaining a phase mono pulse output value from the signals despread by said despreading means and estimating an arrival angle AAO from said phase mono pulse output value; And positioning means for determining the position of the mobile station based on the arrival time TOA and the arrival angle AAO.

In addition, the present invention provides a method for determining a terminal position in a wireless communication system, the method comprising: obtaining and tracking an in-phase pseudo noise code of first and second received signals received from a mobile station through first and second antennas in the same base station; A first step of synchronizing and predicting arrival time (TOA); A second step of demodulating the first and second received signals by in-phase carrier and quadrature carrier and despreading by the in-phase pseudo noise code; Obtaining a phase mono pulse output value from the despread signals and estimating an angle of arrival (AOA) from the phase mono pulse output value; And a fourth step of determining the position of the mobile station based on the arrival time TOA and the angle of arrival AAO.

In addition, the present invention relates to the in-phase pseudo noise of first and second received signals received from a mobile station via a first and a second antenna in a same base station in a wireless communication system having a processor to determine the position of the mobile station. Acquiring and tracking code to synchronize and predict time of arrival (TOA); A function of demodulating the first and second received signals by an in-phase carrier and a quadrature carrier and then despreading the in-phase pseudo noise code; Obtaining a phase mono pulse output value from the despread signals and estimating an angle of arrival (AOA) from the phase mono pulse output value; And a computer readable recording medium having recorded thereon a program for realizing a function of determining the position of the mobile station based on the arrival time TOA and the arrival angle AAO.

The present invention is to determine the position of a wireless terminal (mobile station) receiving a service in a CDMA mobile communication network, three signals required for terminal location determination as the cell design of the CDMA mobile communication network such as cellular, PCS, IMT-2000 is optimized Hearability problem that can not receive the error occurs, and as a way to improve this is to enable positioning in one base station.

To this end, the present invention measures the TOA and AOA for the reverse link of the CDMA mobile communication network to enable positioning at one base station. That is, the TOA and the AOA are simultaneously measured for positioning at one base station, and the diversity antenna used at the base station is used to measure the AOA.

Thus, the present invention can determine the location of the wireless terminal with only one base station in the domestic reality that the number of mobile subscribers such as cellular and PCS exceeds the number of existing landline telephone subscribers, such as emergency call services such as the US wireless E911 service, etc. Various location related services can be provided.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a configuration diagram of an embodiment of a terminal positioning device using a single cell according to the present invention.

As shown in FIG. 1, the terminal positioning apparatus using a single cell according to the present invention includes a first and second antennas 11 and 12 received in a same base station from a wireless terminal (mobile station). Code acquisition and phase for acquiring and tracking in-phase pseudo noise (PN) codes of the second received signals r _1st (t) and r _2nd (t) to synchronize and predict the time of arrival (TOA) τ The delay synchronizer 13 and the first and second received signals r _1st (t) and r _2nd (t) are respectively demodulated by in-phase carrier and quadrature carrier and then inversed by in-phase pseudo noise code. The phase monopulse output value is obtained from the despreading section 14 for spreading and the signals a _real , a _imag , b _real , and b _imag despread by the despreading section 14 and reaches from the phase mono pulse output value. A wireless terminal (mobile station) based on the arrival angle estimating unit 15 for estimating the angle AAO (θ) and the arrival time TOA and the angle of arrival AAO. Positioning section 16 for determining the position of the.

The mono pulse is used to form several beams at the same time, to compare the magnitude of the signal reflected on the target, and to estimate the direction of the target at one time.

Monopulse theory began in the field of radar signal processing, the application of electromagnetic waves, and has been applied to earthquake detection using sonar and elastic waves using sound waves.

As shown in FIGS. 2A and 2B, the mono pulse direction estimation technique is largely divided into an amplitude monopulse method (see FIG. 2A) and a phase monopulse method (see FIG. 2B).

Referring to FIG. 2A, the magnitude mono pulse method takes advantage of the fact that the signals incident on the fixed beams A and B obtain different gains a and b according to the angle of incidence. That is, the incident angle of the signal When This can be used to estimate the direction of the target. The magnitude monopulse method has the same relationship between the angle of incidence and the gain (Equation 1).

In Equation 1, RE (·) is an operator that takes a real part.

The beam formed as shown in FIG. 2B may also be used for directional angle estimation. The beam former gains a and b are given according to the angle of incidence of the signal, and the phase of the gain may be used as a function of the signal angle of incidence. In other words, By using the relationship of Equation 2 below, the direction of the target can be estimated. This structure is called a phase monopulse method.

In Equation (2), IM (·) is an operator that takes an imaginary part.

Assume that the k-th user of the CDMA mobile communication system transmits a signal such as (Equation 3).

In equation (3), Represents the m-th data of the k-th user of the in-phase channel and has a value of +1 or -1. ω _c is the carrier frequency and φ _k is the phase offset of the k-th user. Here, the despread signal is expressed by Equation 4 below.

The transmission signal of Equation 3 is received by the antennas 11 and 12 of the base station through the fading channel of Equation 5, and the received signal may be represented as Equation 6. In this case, f _{k, i} is a weight corresponding to the unit impulse response, and τ _{k, i} represents the I-th multipath delay of the k-th user.

In Equation (6), a (θ _{k, i} ) is an L × 1 direction vector for the i-th path signal of the k-th user in the array antennas 11 and 12, and L is an array antenna element. Here, the case where L = 2 is described.

In order to determine the position of the wireless terminal as one base station in the CDMA mobile communication network for the received signal as described above, it is assumed that the base station uses sectors and each sector uses two or more antennas. At this time, the reception antennas 11 and 12 used are positioned at intervals of λ / 2 as shown in FIG. Is the wavelength of the carrier wave.

If the signals received by the two antennas 11 and 12 are r _1st (t) and r _2nd (t), respectively, when the channel change is not taken into consideration, the received signal is simply expressed as in Equation (7). Can be.

In equation (7), the spread signal Since the frequency of the carrier is very large compared to the signal, the signal r _2nd (t) received by the second antenna 12 has a delay of τ only for the carrier with respect to the signal received by the first array antenna 11. It can be seen. Since the degree of this delay is ultimately determined by the angle of incidence of the signals received at the two antennas 11 and 12, if only the phase difference with respect to the delay of the signals received at the two antennas 11 and 12 can be estimated, then the transmitted signal is transmitted. The angle of incidence of the circle can be determined. That is, as shown in FIG. 4, the received signal is demodulated by the in-phase carrier and the quadrature carrier when φ = 0, and then despread by the in-phase PN code. Here, the in-phase PN code is obtained by a synchronization process through code acquisition and code tracking.

Through this process, the first antenna 11 obtains outputs a _real and a _imag , and the second antenna 12 obtains b _real and b _imag .

In this embodiment, since only in-phase channel information of the transmitter is considered, it is assumed that there is no orthogonal phase channel information of the transmitter. However, the same result can be obtained by considering the quadrature phase channel information of the transmitter at the same time.

In general, the relationship between the incidence angle and the output value of the phase monopulse is equal to (Equation 8), so that the outputs a _real , a _imag , b _real and b _imag are summed into Then, a relationship as shown in Equation 9 is established between the incident angle of the signal and the output value of the mono pulse.

Assuming that the transmitted signal passes through the ideal channel and undergoes a fully synchronized code despreading process (13,14), the output at each stage is given by (10).

In Equation 10, G is the length of the matched filter used for code acquisition.

Substituting Equation 10 into Equation 9 above, Equation 11 is obtained.

On the other hand, since the delay time τ and θ have the same relationship as (Equation 12), the incident angle can be estimated from the output value of the phase mono pulse.

The relationship between the incidence angle of the phase mono pulse and the output value is obtained from Equation (10) and Equation (12).

A lookup table can be used to obtain such a phase mono pulse output value, thereby speeding up the response time. The relationship between the incident angle and the output value used in the lookup table can be seen through FIG. 5.

In fact, in the mobile communication channel, the phase mono pulse output value shown in FIG. 5 may be different due to noise, multipath interference, and code synchronization error. Therefore, the angle of occurrence of the slightest error is determined as the incident angle by comparing the look-up table created using Equation 13 with the phase mono pulse output value of the actually received signal.

The position estimation process of the proposed system for the output value of the phase mono pulse is summarized as follows.

As shown in FIG. 4, the distance between the mobile station and the base station is determined through code acquisition and code tracking of the signals received by the antennas 11 and 12, and the first and second array antennas 11, 12) The phase mono pulse method is applied to the incoming signal to determine the incident angle of the signal. The position of the mobile station can be estimated from the distance and direction information through the above process.

6 is a flowchart illustrating a method for determining a terminal location using a single cell according to the present invention.

As shown in FIG. 6, the method for determining a terminal location using a single cell according to the present invention includes first and second antennas from a wireless terminal (mobile station) through first and second antennas 11 and 12 in the same base station. 2 When the received signals r _1st (t) and r _2nd (t) are received (601), the code acquisition and phase delay synchronizer 13 in-phase pseudo noise (PN) codes of the first and second received signals. The acquisition and tracking are synchronized (602) to predict the arrival time (TOA) τ (603). Here, the arrival time TOA is used to determine the distance between the wireless terminal (mobile station) and the base station (distance information).

The despreader 14 receives the first and second reception signals r _1st (t) and r _2nd (t) received through the array antennas 11 and 12 by using an in-phase carrier and a quadrature carrier. After demodulation, despread by in-phase pseudo noise code.

The phase mono pulse output value is then obtained from the signals a _real , a _imag , b _real , and b _imag despread by the despreader 14 in the arrival angle estimator 15, and the arrival angle is determined from the phase mono pulse output value. (AOA) (θ) is estimated (606). In this case, a lookup table is used to obtain a phase mono pulse output value, thereby speeding up the response time. Here, the arrival angle AAO means an angle of incidence (direction information) estimated from a phase difference with respect to a delay of a signal received through the two array antennas 11 and 12.

Finally, the position determination unit 16 determines the position of the wireless terminal based on the distance information (reach time (TOA)) and the direction information (reach angle AAO).

As described above, the present invention proposes a method for determining the location of a wireless terminal used in a CDMA mobile communication network such as cellular, PCS, and IMT-2000. . When this method is combined with a more accurate positioning method that can be applied in a Hearability region, it is possible to receive a variety of location-related services not only in the existing CDMA mobile communication network established nationwide, but also in the newly constructed IMT-2000 network. Lose.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains, and the above-described embodiments and accompanying It is not limited to the drawing.

As described above, the present invention can estimate the location of a mobile station using only one base station in an area with poor Hearability, and thus provides various information such as information guidance, vehicle tracking, and mobile yellow page service in an unfamiliar area. It is effective to continuously provide location-related services.

Claims (14)

In the terminal position determining apparatus in a wireless communication system, Synchronization and arrival time for acquiring and tracking in-phase pseudo noise codes of the first and second received signals received from the mobile station through the first and second antennas in the same base station to synchronize and predict the time of arrival (TOA). Prediction means; Despreading means for despreading the first and second received signals by in-phase carrier and quadrature carrier, respectively, and then despreading by the in-phase pseudo noise code; Arrival angle estimating means for obtaining a phase monopulse output value from the signals despread by said despreading means and estimating an arrival angle AAO from said phase monopulse output value; And Positioning means for determining the position of the mobile station based on the arrival time TOA and the arrival angle AAO Terminal positioning device using a single cell in a wireless communication system comprising a. The method of claim 1, The reaching angle estimating means, Device for positioning a terminal using a single cell in a wireless communication system, characterized in that for reducing the response time by using a lookup table to obtain the phase mono pulse output value. The method of claim 1, The first and second antennas, Substantially, a terminal positioning device using a single cell in a wireless communication system, characterized in that spaced apart by λ / 2 (λ is a wavelength of the carrier wave) in the same base station. The method of claim 1, The second received signal received by the second antenna, And a delay time by a time of arrival (TOA) only for a carrier wave with respect to the first received signal received by the first antenna. The method of claim 1, The despread signals of the arrival angle estimating means, respectively, Substantially, a terminal position determination apparatus using a single cell in a wireless communication system, characterized in that it has the value as the following equation. (Where G is the length of the matched filter used to obtain the code) The method of claim 1, The phase mono pulse output value is Terminal positioning apparatus using a single cell in a wireless communication system, characterized in that the relationship between the incident angle of the mono pulse and the following equation. The method according to any one of claims 1 to 6, The process of determining the location of the mobile station, The distance between the mobile station and the base station is determined through code acquisition and code tracking of the first and second received signals received by the first and second antennas, and the synchronized pseudo noise code is used to determine the distance. And determining the angle of incidence of the signal by applying a phase monopulse method to the first and second received signals entering the second antenna, and then determining the position of the mobile station from distance and direction information. Terminal location determination device using a single cell. In the terminal location determination method in a wireless communication system, A first step of obtaining and tracking in-phase pseudo noise codes of the first and second received signals received from the mobile station via the first and second antennas in the same base station to synchronize and predict the arrival time (TOA); A second step of demodulating the first and second received signals by in-phase carrier and quadrature carrier and despreading by the in-phase pseudo noise code; Obtaining a phase mono pulse output value from the despread signals and estimating an angle of arrival (AOA) from the phase mono pulse output value; And A fourth step of determining the position of the mobile station based on the arrival time TOA and the arrival angle AAO Terminal location determination method using a single cell in a wireless communication system comprising a. The method of claim 8, The despread signals are each Substantially, a method for determining a location of a terminal using a single cell in a wireless communication system, characterized by having a value equal to the following equation. (Where G is the length of the matched filter used to obtain the code) The method of claim 8, The first and second antennas, Substantially, a method for determining a location of a terminal using a single cell in a wireless communication system, characterized in that spaced apart λ / 2 (λ is a wavelength of the carrier wave) in the same base station. The method of claim 8, The second received signal received by the second antenna, The method of claim 1, wherein the delay of the first received signal received by the first antenna is as long as the arrival time (TOA) for the carrier. The method according to any one of claims 8 to 11, The third step, Obtain a phase mono pulse output value from the despread signals, estimate an angle of arrival (AOA) from the phase mono pulse output value, and reduce a response time by using a lookup table to obtain the phase mono pulse output value. Terminal location determination method using a single cell in a wireless communication system, characterized in that. The method of claim 12, The phase mono pulse output value is A terminal positioning method using a single cell in a wireless communication system, characterized by having a relationship between an incident angle of a mono pulse and the following equation. In a wireless communication system having a processor for determining the position of a mobile station, Obtaining and tracking in-phase pseudo noise codes of the first and second received signals received from the mobile station through the first and second antennas in the same base station to synchronize and predict the time of arrival (TOA); A function of demodulating the first and second received signals by an in-phase carrier and a quadrature carrier and then despreading the in-phase pseudo noise code; Obtaining a phase mono pulse output value from the despread signals and estimating an angle of arrival (AOA) from the phase mono pulse output value; And A function of determining the position of the mobile station based on the arrival time (TOA) and the arrival angle (AOA) A computer-readable recording medium having recorded thereon a program for realizing this.