KR102287266B1 - Wireless localization ranging method between devieces using cooperation terminal and system thereof - Google Patents

Abstract

The present invention relates to a wireless localization ranging method between terminals using a cooperation terminal and a system thereof. According to the present invention, the wireless localization ranging method based on a wireless network system comprises the following steps: transmitting and receiving a ranging request signal by a first terminal and a second terminal; determining whether to request cooperative positioning by comparing first and second channel quality values, which are channel quality values with a counterpart terminal estimated from the ranging request signal received through the counterpart terminal, with a reference value, respectively; when the cooperative positioning request is determined, receiving, by the first and second terminals, a response signal after broadcasting the cooperation request signal to one or more neighboring terminals, respectively; selecting a terminal existing in a common channel quality region between the first and second terminals among the neighboring terminals on the basis of a response signal as a cooperative terminal to allow the cooperative terminal to transmit a cooperative signal; and measuring a distance between the terminals through transmission and reception of ranging frame signals between the first and second terminals, and correcting a distance measurement error by performing clock synchronization or frequency offset compensation between the terminals based on the cooperation signal. Accordingly, when a channel environment between terminals does not satisfy ranging performance requirements during wireless positioning between the terminals, a cooperative signal by neighboring terminals is used to detect a wireless positioning ranging signal, thereby reducing a wireless positioning ranging error and increasing positioning accuracy.

Description

TECHNICAL FIELD [0002] Wireless localization ranging method between devices using cooperation terminal and system thereof

The present invention relates to a method and system for radio positioning ranging between terminals using a cooperative terminal, and more particularly, to a radio positioning ranging that can minimize the radio positioning ranging error problem based on radio detection by utilizing the cooperation of adjacent terminals. It relates to methods and systems.

The radio positioning ranging technology is defined as a technology for measuring the separation distance between terminals through RF strength or signal detection between terminals. Furthermore, the radiolocation technology is to estimate the exact location of the terminal node, it is estimated based on the ranging (Ranging).

The exact location of the terminal node for which the location is to be known can be estimated based on the relative ranging between the base station or anchor node at the specified location, and the most representative GPS terminal node.

Recently, the IoT system for providing various services anytime and anywhere by connecting a number of devices and things requires the implementation of low-cost and low-power devices, and the demand for positioning technology for various location-based IoT applications is increasing. In addition, to support location-based IoT services, there is a trend to include wireless detection-based wireless positioning technology in existing IoT technologies, such as positioning methods using low-cost wireless technology without GPS support and location tracking methods.

Short-distance communication technologies such as UWB, WiFi, BLE, and RFID are mainly applied to location tracking technology based on wireless detection. Position measurement is performed using the

The radio detection-based radio positioning technology is configured based on the ranging technology. Most of the IoT technologies are short-distance communication technologies, and provide wireless positioning in an infrastructure environment. Of course, it is important to estimate the exact location of a terminal node for a wide area IoT service, but if it provides an estimate of the separation distance between devices, it can be importantly used in low-power location-based applications.

The radio detection-based positioning ranging technology is performed by measuring time information such as ToA (Time of Arrival) or ToF (Time of Flight), which is the propagation delay time of a radio signal between two devices, It is performed by extracting accurate time information of the transmitter and the receiver through estimated detection of a signal with processing gain), and estimating the relative position and separation distance between the two terminals through the difference in radio wave arrival time. When using a relative time difference using a plurality of positioning beacons, it is also possible to position a terminal in a two-dimensional space. Most positioning techniques are implemented using relative visual differences.

In the radio positioning method based on the propagation delay time, the frequency/clock synchronization offset between positioning terminals causes accuracy and precision errors when measuring the propagation time and measuring the propagation delay time. The local oscillator (oscillator) of each terminal has an error, and this absolute and device-to-device relative error causes a clock frequency offset and a carrier frequency offset, resulting in an accuracy error when measuring propagation delay time.

The clock/frequency offset between devices causes a time error according to the relative clock frequency ratio. In particular, the frequency offset between devices causes signal loss and distortion when detecting the preamble performed for detecting the delay time, resulting in precision error when detecting accurate time synchronization. make it This results in a large positioning error when detecting radio positioning ranging, resulting in performance degradation.

1 is a diagram illustrating a ranging detection principle based on a propagation delay time of a radio signal.

1 illustrates a technique for detecting a propagation delay time through transmission and reception of a radio signal (Ranging frame) between two devices A and B, and ranging a distance between the two devices from this.

T _Round is the round-trip time, T _reply is the reply time, the reference point is the reference time point for propagation delay time detection, and e _A and e _B are the clock offset errors of each device A and B. , T _ToF is a propagation delay time (ToF; Time of flight), and Te is a ranging timing error.

로 정의되지만, 실제 전파지연시간은 클럭 오프셋 오차가 반영되어

로 검출된다. 이에 따라, 레인징 타이밍 오차 역시

와 같이 발생한다.Here, the ideal propagation delay time without clock offset error is

However, the actual propagation delay time reflects the clock offset error.

is detected as Accordingly, the ranging timing error is also

occurs with

In general, it is possible to calculate the distance between two devices using the detected propagation delay time ToF and C (velocity of light). If there is a clock offset between the two devices _{, an error occurs in the measurement of the propagation delay time T ToF} , so the distance between the devices is calculated. Also, an error (ranging timing error) is generated.

Of course, a two-way ranging (TWR) technique exists as a method of reducing a detection error due to a relative offset between terminals. However, in the case of the TWR method, while compensating for an error due to a relative offset between terminals, the ranging frame must be transmitted once more. Therefore, there is a disadvantage in that a loss of time resources occurs.

2 is a diagram for explaining a detection error according to a transmission/reception reference point of two terminals. As shown in FIG. 2 , the difference between the transmission/reception reference points of the two devices is also a factor of lowering the ranging accuracy.

In FIG. 2, the first reception reference point (e _A =e _B = 0) represents an ideal reception reference point. The reception reference point No. 3 represents the actually detected reception reference point of the receiver to which the frequency/clock offset is additionally reflected.

로 나타나므로,

만큼의 레인징 오차가 발생하게 된다. The actually detected reception reference point is affected by a relative frequency offset, SNR loss, line of sight (LOS) loss, and the like. In addition, additional errors may occur in the last detected reception reference point depending on the frame detection performance. As a result, the actual distance between the two terminals is d, but the radiolocation result is

Since it appears as

As much as a ranging error occurs.

As such, the radio localization ranging accuracy based on radio detection is affected by LOS path detection performance, SNR, oscillator error, and a relative frequency/clock offset between two devices. Therefore, for accurate positioning, it is necessary to correct or supplement the components that cause the above-mentioned errors.

In addition, the IoT device has a relatively large frequency error (frequency offset of several ppm level) according to the application of a low-cost module (especially an oscillator). Such a frequency error generates a ranging estimation error according to a relative clock offset error when calculating radio positioning ranging, and acts as a deterioration factor in accurate timing detection performance for a ranging signal, thereby generating a final ranging detection error.

Therefore, in order to support wireless positioning ranging in the low-cost Internet of Things, a technology for improving and correcting relative frequency offset estimation is essential.

The technology that is the background of the present invention is disclosed in Korean Patent Registration No. 10-1304849 (published on September 5, 2013).

The present invention reduces the radio positioning ranging error by utilizing the cooperative signal by the neighboring terminals to detect the radio positioning ranging signal when the communication environment between the terminals does not satisfy the ranging performance requirement when performing the wireless positioning between the terminals An object of the present invention is to provide a method and system for radio positioning ranging between terminals using a cooperative terminal to improve accuracy.

The present invention provides a wireless positioning ranging method between terminals using a cooperative terminal based on a wireless network system, the first terminal and the second terminal mutually transmitting and receiving a ranging request signal; Comparing the first and second channel quality values, which are channel quality values with the counterpart terminal estimated from one ranging request signal, with a reference value, respectively, and determining whether to request cooperative positioning through a neighboring terminal according to the comparison result; When the positioning request is determined, the first and second terminals each broadcast a cooperation request signal to one or more neighboring terminals, respectively, and then receiving a response signal, and based on the response signal, the first and second terminals among the neighboring terminals Selecting a terminal existing in a common channel quality region between second terminals as a cooperative terminal and operating it to transmit a cooperative signal, and measuring the distance between terminals through transmission and reception of a ranging frame signal between the first and second terminals However, it provides a wireless positioning ranging method between terminals comprising the step of correcting a distance measurement error by performing clock synchronization or frequency offset compensation between terminals based on the cooperation signal.

In addition, the determining whether the cooperative positioning request may include determining the cooperative positioning request when both the first and second channel quality values are smaller than the reference value.

In addition, the cooperation request signal, together with the information for requesting the cooperative positioning, may further include information on a transmission method of the cooperation signal and a channel condition for selection as the cooperative terminal.

In addition, the signal frame structure of the cooperation request signal includes a preamble, a header, and a payload section, the information for requesting the cooperative positioning, the transmission method of the cooperative signal, and the channel condition for selection as the cooperative terminal are the header may be sequentially inserted within the EXT area of

In addition, the transmission method of the cooperative signal is a first transmission method in which the cooperative terminal broadcasts a beacon signal for clock synchronization between terminals, and the cooperative terminal is the ranging frame of each of the first and second terminals and a second transmission method for transmitting inter-terminal frequency offset information estimated through signal observation to the first and second terminals, respectively.

In addition, the transmission method of the cooperation signal may be determined by the following equation based on the sequence length (N) and the operating bandwidth (B) of the preamble applied to the ranging frame signal.

Here, CoMODE denotes the determined transmission scheme, mode 0 denotes the first transmission scheme, mode 1 denotes the second transmission scheme, N _TH denotes a preset threshold sequence length, and B _TH denotes a preset threshold bandwidth.

Further, the step of selection of the cooperative MS is, by analyzing the response signal, it is possible to satisfy the condition of Equation below in the wireless network in the candidate terminals (r _i).

는 후보 단말 r_i이 제1 단말로부터 수신한 협력 요청 신호로부터 추정한 제1 단말과의 채널 품질,

는 후보 단말 r_i이 제2 단말로부터 수신한 협력 요청 신호로부터 추정한 제2 단말과의 채널 품질,

는 협력 단말의 선정을 위한 기준 채널 품질값을 나타낸다.Here, Λ is a set of peripheral terminals satisfying {·},

is the channel quality with the first terminal estimated from the cooperation request signal received by the candidate terminal r _{i from the first terminal,}

is the channel quality with the second terminal estimated from the cooperation request signal received by the candidate terminal r _{i from the second terminal,}

denotes a reference channel quality value for selection of a cooperative terminal.

And, in the present invention, in a wireless positioning ranging system between terminals using a cooperative terminal based on a wireless network system, the first channel quality value with the counterpart terminal estimated from the ranging request signal received through the counterpart terminal. The first and second channel quality values are compared with a reference value, respectively, and it is determined whether or not a cooperative positioning request is made through a neighboring terminal according to the comparison result, and when the cooperative positioning request is determined, the first and second terminals send a cooperation request signal The first and second terminals each receive a response signal after broadcasting to the above peripheral terminals, and transmit the response signal after receiving the cooperation request signal from the first and second terminals, and selectable as a cooperative terminal It includes at least one neighboring terminal, wherein the first and second terminals select a terminal existing in a common channel quality region between the first and second terminals among the neighboring terminals as a cooperative terminal based on the response signal. Operates to transmit a cooperation signal, and measures the distance between terminals through transmission and reception of a ranging frame signal between the first and second terminals, and measures the distance by performing clock synchronization or frequency offset compensation between terminals based on the cooperation signal A wireless positioning ranging system for correcting errors is provided.

In addition, the first terminal and the second terminal may determine the cooperative positioning request when both the first and second channel quality values are smaller than the reference value.

In addition, the first terminal and the second terminal, when the cooperative station selection can navigate around the terminal satisfying the condition of Equation below in the response signal analysis to the wireless network within a candidate terminal (r _i) a.

는 후보 단말 r_i이 제1 단말로부터 수신한 협력 요청 신호로부터 추정한 제1 단말과의 채널 품질,

는 후보 단말 r_i이 제2 단말로부터 수신한 협력 요청 신호로부터 추정한 제2 단말과의 채널 품질,

는 협력 단말의 선정을 위한 기준 채널 품질값을 나타낸다.Here, Λ is a set of peripheral terminals satisfying {·},

is the channel quality with the first terminal estimated from the cooperation request signal received by the candidate terminal r _{i from the first terminal,}

is the channel quality with the second terminal estimated from the cooperation request signal received by the candidate terminal r _{i from the second terminal,}

denotes a reference channel quality value for selection of a cooperative terminal.

According to the present invention, if the channel environment does not satisfy the ranging performance requirement when performing wireless positioning between terminals, the cooperative signal by the neighboring terminals is used to detect the wireless positioning ranging signal to reduce the wireless positioning ranging error and improve positioning accuracy. can be improved

1 is a diagram illustrating a ranging detection principle based on a propagation delay time of a radio signal.
2 is a diagram for explaining a detection error according to a transmission/reception reference point of two terminals.
3 is a diagram illustrating a wireless positioning ranging system according to an embodiment of the present invention;
FIG. 4 is a diagram illustrating a concept of wirelessly positioning a distance between terminals by mutually transmitting and receiving a ranging frame signal between the first and second terminals of FIG. 3 .
5 is a diagram illustrating a wireless positioning ranging method according to an embodiment of the present invention.
6 is a diagram exemplarily illustrating a frame structure of a cooperation request signal according to an embodiment of the present invention.
7 is a diagram for explaining the operation of a peripheral terminal in an embodiment of the present invention.

Then, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them.

3 is a diagram illustrating a wireless positioning ranging system according to an embodiment of the present invention, and FIG. 4 is a concept of wirelessly positioning a distance between terminals by mutually transmitting and receiving ranging frame signals between the first and second terminals of FIG. 3 the drawing shown.

As shown in FIG. 3 , the wireless positioning ranging system according to an embodiment of the present invention includes a first terminal 100 , a second terminal 200 , and peripheral terminals 300 and 400 .

Each of the terminals 100, 200, 300, and 400 illustrated in FIG. 3 corresponds to a terminal including a wireless communication function capable of communicating with each other within a wireless network, and various known wireless terminal devices (eg, user terminals, smart phones, Internet of Things devices, etc.) may correspond to

The first terminal 100 and the second terminal 200 transmit and receive radio signals to and from each other, and based on this, perform radio positioning ranging for measuring the distance between the terminals. The radio positioning ranging between terminals measures the distance between terminals using a radio signal, and the distance between two devices is measured through time-based ranging.

The first terminal 100 and the second terminal 200 each include a wireless transmission/reception module for wireless signal transmission and reception, a processor for wireless positioning ranging and various signal processing, and a memory for data storage.

The first and second terminals 100 and 200 can exchange and share various types of processing information and calculation data with each other in the process of performing radio positioning ranging, and either one of the two terminals is required based on the mutually shared data. In accordance with this, it may operate as a master and perform various calculations and processing to deliver the processing result to the remaining terminals, or both terminals may perform the same operation processing in an equal position to compare and analyze the processing results with each other.

As shown in FIG. 4 , the first terminal 100 and the second terminal 200 transmit and receive a mutual ranging frame signal to detect a propagation delay time (ToF), and based on this, radio positioning ranging carry out

Each of the terminals 100 and 200 detects a reference time point (reference point) for detecting a propagation delay time (ToF) from a ranging frame signal received from the other terminal through a preamble sequence, etc., and calculates a propagation delay time through this. carry out In this case, if the detection error of the propagation delay time is reduced, the ranging error can be reduced.

However, if there is a clock offset between devices, an error occurs when measuring the propagation delay time, and the error in the propagation delay time causes a ranging error. In addition, the frequency offset between devices generates a detection error of the signal reference point of the transceiver for detecting the propagation delay time as shown in FIG. 2, which causes a propagation delay time measurement error.

An embodiment of the present invention is Propagation delay time detection is achieved by improving the time synchronization detection performance of the ranging frame signal sent by the other terminal through cooperation between the two terminals and the neighboring terminal, or by compensating for the frequency offset error between terminals when calculating the distance between terminals. By reducing the error, ultimately, the radio positioning ranging error is reduced, thereby providing a more reliable positioning result.

In addition, in the embodiment of the present invention, when performing radio positioning ranging between two devices, if the channel quality between the two terminals satisfies the required quality level, general radio positioning ranging is performed between devices, but if the required quality level is not satisfied, the network surrounding By utilizing the cooperative signal by the device to detect the wireless positioning ranging signal, the distance measurement accuracy is improved by time synchronization detection performance or error correction.

3 is an example arrangement for wireless positioning ranging detection between two devices A and B, wherein the first terminal 100 and the second terminal 200 are the terminals A and B, and the third terminal 300 which is adjacent terminal. and the fourth terminal 400 are denoted by terminals C and D, respectively.

Zone A indicates a terminal A of the far-end terminal of the terminal B and the wireless transceiver when the reference quality value (Q _REQ) or more quality zone, Zone B is the quality value based upon the terminal A and the radio transmission and reception to the terminal B the correspondent node (Q _REQ) indicates the above quality area. Here, terminal C is a device terminal selected for cooperation, and is located in the overlapping area between Zone A and Zone B, that is, in the common channel quality area of terminals A and B.

In the case of an embodiment of the present invention, when the channel quality between the two terminals A and B does not satisfy the required quality, among the adjacent terminals C and D, terminal C, which is a neighboring terminal, existing in the common channel quality area between terminals A and B Decide on a cooperative beacon.

Terminal C transmits and provides a cooperation signal at the request of terminals A and B. To this end, the terminal broadcasts a beacon signal (Co-signal) or transmits frequency offset correction information obtained by observing the signals of the two terminals to the terminal. A cooperation signal is transmitted by transmitting to A and B.

The beacon signal is used as a signal for clock synchronization between the two terminals before the two terminals detect a ranging preamble for propagation delay time detection. The two terminals synchronized by the beacon signal can improve the distance estimation accuracy by compensating for a synchronization offset loss between the terminals when the ranging preamble is detected. In addition, the correction information is used as correction information for compensating for a clock frequency offset when calculating a distance between two terminals.

In this way, the cooperative signal (Co-signal) transmitted by the cooperative terminal is used to reduce a distance measurement error, ie, a ranging error, when performing radio positioning ranging for measuring a distance between two terminals.

Hereinafter, a wireless positioning ranging method according to an embodiment of the present invention will be described in more detail based on the above description.

5 is a diagram illustrating a wireless positioning ranging method according to an embodiment of the present invention.

First, the first terminal 100 and the second terminal 200 mutually transmit and receive a ranging request signal (S510). In this case, after the first terminal 100 transmits a signal to the second terminal 200 , the second terminal 200 transmits a signal to the first terminal 100 to exchange signals with each other.

Thereafter, the first terminal 100 and the second terminal 200 each estimate a channel quality value from a received signal received through the other terminal and compare it with a reference value ( S520 ).

A technique for measuring or estimating a channel state or channel quality from a received signal corresponds to a known method. Here, indicators such as signal-to-noise (SNR), signal-to-interference ratio (SIR), signal-to-interference plus noise ratio (SINR), and received signal strength indicator (RSSI) may be used as channel quality values. .

In step S510 , the first terminal 100 estimates a first channel quality value that is a channel state with the second terminal 200 from the signal received from the second terminal 200 , and the second terminal 200 determines the first terminal A second channel quality value that is a channel state with the first terminal 100 may be estimated from the signal received from 100 , and the estimated result may be exchanged and shared.

The first and second terminals 100 and 200 determine whether to request cooperative positioning through a neighboring terminal according to a result of comparing the first and second channel quality values (S530).

If both the first and second channel quality values are greater than or equal to the reference value, the channel environment (communication environment) between the two terminals 100 and 200 satisfies a certain requirement. It is sufficient to perform general radio positioning ranging.

However, as shown in Equation 1 below, when both the first and second channel quality values are less than the reference value, the first and second terminals 100 and 200 determine that cooperation of neighboring terminals is required and determine to request cooperative positioning. do.

는 제1 단말(100)이 제2 단말(200)로부터 수신한 무선 프레임으로부터 추정한 채널 상태(제1 채널 품질값)을 나타내고,

는 제2 단말(200)이 제1 단말(100)로부터 수신한 무선 프레임으로부터 추정한 채널 상태(제2 채널 품질값)을 나타낸다.here,

represents the channel state (first channel quality value) estimated from the radio frame received by the first terminal 100 from the second terminal 200,

denotes a channel state (second channel quality value) estimated from a radio frame received by the second terminal 200 from the first terminal 100 .

은 협력 측위 요청 결정을 위해 설정된 최소 품질 요구값(임계값)으로 사전에 미리 설정될 수 있으며, 이는 협력 단말 선정을 위한 기준 채널 품질값

보다는 큰 값으로 설정될 수 있다.reference value

may be preset as a minimum quality requirement value (threshold value) set for cooperative positioning request determination, which is a reference channel quality value for cooperative terminal selection

It can be set to a value greater than

When the cooperative positioning request is determined, the first and second terminals 100 and 200 receive a response signal after broadcasting the cooperation request signal to one or more neighboring terminals, respectively (S540).

Here, the cooperation request signal is information for requesting cooperative positioning (CoREQ; Co-Ranging Request) in addition to the transmission method of the cooperative signal (CoMODE; cooperation mode) and the channel condition for being selected as a cooperative terminal (CoCOND; Cooperative beacon condition) for Additional information may be included. The two terminals 100 and 200 broadcast and transmit the same configuration of the cooperation request signal in the form including the above-described three pieces of information.

6 is a diagram exemplarily illustrating a frame structure of a cooperation request signal according to an embodiment of the present invention.

6, the frame structure of the cooperation request signal basically includes a preamble section (Preamble), a header section (header), and a payload section (Payload). Here, the header section is again divided into a basic header area and an EXT area, and the three pieces of information (CoREQ, CoMODE, and CoCOND) are sequentially inserted into the EXT area.

The cooperative signal request information (CoREQ) is information for requesting cooperative ranging. If CoREQ=1, it means cooperative ranging, and if CoREQ=0, it means normal ranging. Of course, since step S540 is actually a step of requesting coordinated positioning to a neighboring terminal, the CoREQ of the cooperation request signal is transmitted with a value of 1.

The cooperative signal transmission method (CoMODE) is transmitted to the neighboring terminal in a state included in the cooperation request signal, and is selected as a preset value according to the IoT device operating environment, or estimates the radio positioning operation environment in terminals A and B, which are target devices. can be actively selected. That is, the transmission method of the cooperative signal may be preset to the two terminals A and B or may be set after the step S530 of determining the cooperative positioning request.

In an embodiment of the present invention, the cooperative signal transmission scheme (CoMODE) has two schemes including a first transmission scheme (Mode 0) and a second transmission scheme (Mode 1), and when CoMODE = 0, Mode 0, When CoMODE=1, Mode 1 is indicated.

Mode 0 is a first transmission scheme in which the cooperative terminal 300 broadcasts a beacon signal for clock synchronization between terminals, and Mode 1 is the cooperative terminal 300 in each lane of the first and second terminals 100 and 200 This is a second transmission method in which the inter-terminal frequency offset information estimated through observation of the jing frame signal is transmitted to the first and second terminals 100 and 200, respectively.

That is, the cooperative signal sent by the cooperative terminal 300 is divided into a broadcasting beacon signal and a positioning correction signal, which is determined according to a transmission method (CoMODE) of the cooperative signal.

Therefore, when CoMODE of the cooperation request signal is set to 0, the cooperative terminal 300 transmits a cooperative signal through broadcasting of a beacon signal, and when CoMODE is set to 1, the cooperative terminal 300 transmits a positioning correction signal to each terminal ( 100,200) to transmit a cooperation signal.

The cooperative signal transmission scheme (CoMODE) is determined by Equation 2 below.

Here, CoMODE is the determined transmission method, mode 0 is the first transmission method, mode 1 is the second transmission method, N is a ranging preamble length, B is a ranging frame bandwidth, N _TH is a preset threshold sequence length, B _TH is Indicates a preset threshold bandwidth.

According to Equation 2, _{mode 0 is determined when N > N TH} or B < B _TH , and mode 1 is determined otherwise.

That is, the transmission method of the cooperation signal is determined according to the sequence length (N) and the operating bandwidth (B) of the preamble applied to the ranging frame signal. Here, the ranging frame signal may correspond to a radio signal generally used for radio positioning ranging between the two terminals 100 and 200 as shown in FIG. 4 .

An embodiment of the present invention is based on a radio positioning ranging detection method based on preamble signal detection. The main performance items of radio positioning ranging are estimable distance, positioning accuracy, energy use (related to transmission time), etc. In general, it is closely related to the preamble sequence length (L) for ranging estimation and the ranging operation bandwidth (B). related Accordingly, the transmission method of the cooperative signal may be mutually determined at the time of the initial radiolocation ranging request and response according to the operation environment and performance target, and the channel environment between the radiolocation target terminals.

For long-distance positioning, a method of improving reception performance and detection accuracy by applying a longer sequence due to channel degradation between transceivers or a method of improving sensitivity through narrowband channel operation is applied. However, in environments such as longer sequence application (N > N _TH ) and narrowband operation (B < B _TH ), performance degradation due to initial frequency offset can occur seriously, so in this case, it is advantageous to respond to the environment by setting mode 0 do. Based on this, the embodiment of the present invention can obtain more accurate radiolocation accuracy by determining the transmission method of the cooperative signal according to the preamble sequence length or the operating bandwidth.

The channel condition (CoCOND) for selecting the cooperative terminal is used to check whether the neighboring terminals 300 and 400 in the network satisfy the channel condition of Equation 3 below. Equation 3 corresponds to a condition for determining whether a candidate terminal exists in a common channel quality region between the two terminals 100 and 200 (the overlapping region of Zones A and B in FIG. 3 ).

는 후보 단말 r_i이 제1 단말로부터 수신한 협력 요청 신호로부터 추정한 제1 단말과의 채널 품질,

는 후보 단말 r_i이 제2 단말로부터 수신한 협력 요청 신호로부터 추정한 제2 단말과의 채널 품질,

는 협력 단말의 선정을 위한 기준 채널 품질값을 나타낸다.Here, Λ is a set of peripheral terminals satisfying {·},

is the channel quality with the first terminal estimated from the cooperation request signal received by the candidate terminal r _{i from the first terminal,}

is the channel quality with the second terminal estimated from the cooperation request signal received by the candidate terminal r _{i from the second terminal,}

denotes a reference channel quality value for selection of a cooperative terminal.

Therefore, the first and second terminals 100 and 200 select the third terminal 300 satisfying Equation 3 among the neighboring terminals 300 and 400 based on the response signal received after broadcasting the cooperation request signal as the cooperative terminal. It operates to transmit the cooperation signal and receives the cooperation signal from the third terminal 300 (S540).

와

을 조합하여 가장 우수한 채널 상태를 가진 하나를 협력 단말로 선정할 수 있다. If there are a plurality of peripheral terminals satisfying Equation 3, the first and second terminals 100 and 200 may randomly select one of them,

Wow

can be combined to select one with the best channel state as the cooperative terminal.

,

을 포함한 응답을 보냄으로써 각 단말(100,200)에서 직접 수학식 3의 만족 여부를 판별하도록 할 수 있다.Network in the neighboring terminals (300 400) corresponds to the selection of the candidate terminals (r _i) in cooperation terminal. After receiving the cooperation request signal transmitted by the two terminals 100 and 200, the peripheral terminals 300 and 400 measure the channel quality with each terminal from the signal they receive by referring to the required channel condition (CoCOND) included therein, and the equation It is possible to determine whether or not 3 is satisfied and send a response including the judgment result. In addition, each peripheral terminal receives the channel measurement value

,

By sending a response including ?

Thus, the first and second terminals (100,200) is a wireless network in the candidate terminals (r _i) of the third terminal the cooperation a third terminal 300, the transmitted signal (300) selected as a cooperative station, and sends the results can receive

When the cooperation signal is received, when the transmission mode of the cooperation signal is Mode 0, the two terminals 100 and 200 receive the beacon signal broadcast by the third terminal 300, and in Mode 1, the third terminal 300 ) receives the inter-terminal correction information calculated through the ranging frame signal received from each of the two terminals.

In addition, Mode 1 corresponds to a listen and report technique. The first and second terminals 100 and 200 transmit a ranging frame signal before the actual radio positioning ranging process, and the third terminal 300 transmits a ranging frame signal to these two terminals 100 and 200 . ) to calculate and feed back the frequency offset between the signals by observing and comparing them.

Thereafter, the first and second terminals 100 and 200 perform inter-terminal distance measurement (radio positioning ranging) through wireless transmission and reception of ranging frame signals to each other, but based on the cooperation signal, inter-terminal clock synchronization or frequency offset compensation By performing this, a distance measurement error (ranging error) is corrected during radio positioning ranging (S550).

Here, the first and second terminals 100 and 200 synchronize the clocks between terminals based on the beacon signal broadcast from the third terminal 300 when receiving the cooperation signal according to Mode 1, and receive the cooperation signal of Mode 2 When received, the frequency offset difference between terminals is compensated based on the frequency offset information received from the third terminal 300 .

Of course, when using the cooperative transmission method of Mode 0, the two terminals 100 and 200 synchronize clocks using the beacon signal received from the third terminal 300, and then transmit and receive ranging frame signals to and from each other in the radio positioning lane perform the jingle When the cooperative transmission method of Mode 1 is used, the two terminals 100 and 200 compensate the clock frequency offset between the two terminals based on the correction information received from the third terminal 300 .

Both methods increase the detection accuracy of the propagation delay time in performing radio positioning ranging based on the ToF detection and ultimately reduce the radio positioning error. The effects of these two transmission modes will be described in more detail as follows.

In the case of Mode 0 using broadcasting of a beacon signal, an offset generated between the two devices is compensated by transmitting a beacon signal for providing synchronization between the two devices. If it is assumed that each device is placed in a poor transmission/reception channel environment due to the distance, performance may deteriorate due to a synchronization error when detecting the transmission/reception start point. In this case, if synchronization is performed prior to performing radio positioning ranging by using the mutual synchronization signal from the cooperative terminal, an effect of improving precision in detecting a ranging signal can be obtained, which can alleviate repetitive ranging signal transmission and reception and time resource efficiency increase the

In addition, general synchronization performance is improved proportionally with respect to SNR, and error variance for synchronization and ranging error is generally inversely proportional to SNR, so a signal from a co-beacon in a better position than the channel environment between two devices Synchronization performance can be relatively high. Therefore, in the case of Mode 0, a precision improvement effect can be obtained through synchronization between two devices using a beacon signal (mutual offset factor compensation).

In addition, in the case of Mode 1 using the listen and report technique, the cooperative terminal receives the ranging signal transmitted from the two devices, detects an error between the two devices, and transmits it to the two devices, thereby providing correction information when calculating the ranging between devices. use it as That is, it is possible to compensate for the ranging error by providing a frequency / clock offset information between the two devices for the compensation for the e _A and e _B component in the cases of Mode 1 1.

The following briefly describes the operation from the standpoint of the neighboring terminal receiving the cooperation request signal. 7 is a diagram for explaining the operation of a peripheral terminal in an embodiment of the present invention.

First, the first and second terminals 100 and 200 broadcast a cooperation request signal, and accordingly, the neighboring terminals 300 and 400 receive a cooperation request signal from each terminal 100 and 200 ( S710 ).

)을 측정하고 제2 단말(200)과의 채널 품질(

)을 측정하여, 수학식 3의 조건을 만족하는지 판단한다(S720). In addition, each of the neighboring terminals 300 and 400 refers to the required channel condition (CoCOND) included in the cooperation request signal, and the channel quality with the first terminal 100 (

) and measure the channel quality with the second terminal 200 (

) to determine whether the condition of Equation 3 is satisfied (S720).

Through this, it can be determined whether each of the neighboring terminals exists in the overlapping area of Zones A and B of FIG. 3 . At this time, since the fourth terminal 400 does not satisfy this, the processor is terminated, but the third terminal 300 satisfies the corresponding condition and prepares for operation as the cooperative terminal 300 ( S730 ).

Here, the third terminal 300 checks the transmission mode (CoMODE) information included in the cooperation request signal prior to transmission of the cooperation signal (S740). The cooperative signal transmission method may be divided into a beacon signal broadcasting method (Mode 0) and a listen and report-based correction information transmission method (Mode 1) according to a transmission mode.

That is, the third terminal 300 broadcasts a beacon signal to the surroundings in the case of Mode 0 (S750), and in the case of Mode 1, receives the ranging frame signal from the terminals A and B (100,200) and analyzes it to connect the two terminals. After calculating the correction information including the frequency offset, it is transmitted to the two terminals 100 and 200, respectively.

The present invention as described above makes it possible to measure the distance between two devices through time-based ranging in an environment that cannot guarantee high SNR and LoS between two terminals.

According to the present invention, when wireless positioning ranging is applied between IoT communication terminals to which low-cost terminals are generally applied, a relatively large frequency/clock error due to application of a low-cost module (especially an oscillator) can be reduced, so that the wireless positioning accuracy and precision can be improved.

In addition, by utilizing data and signals transmitted from the cooperative terminal for synchronization, link performance between terminals can be improved, thereby increasing radio positioning ranging reliability and providing improved performance in terms of radio positioning error.

Although the present invention has been described with reference to the embodiment shown in the drawings, which is only exemplary, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

100: first terminal 200: second terminal
300: third terminal 400: fourth terminal

Claims (14)

In a wireless positioning ranging method between terminals using a cooperative terminal based on a wireless network system,
transmitting and receiving a ranging request signal by the first terminal and the second terminal;
Each of the first and second channel quality values, which are channel quality values with the counterpart terminal estimated from the ranging request signal received through the counterpart terminal, are compared with a reference value, respectively, and whether or not a cooperative positioning request is made through a neighboring terminal according to the comparison result determining;
When the cooperative positioning request is determined, the first and second terminals each receiving a response signal after broadcasting the cooperation request signal to one or more neighboring terminals, respectively;
selecting a terminal existing in a common channel quality region between the first and second terminals from among neighboring terminals based on the response signal as a cooperative terminal and operating to transmit the cooperative signal; and
Measuring a distance between terminals through transmission and reception of a ranging frame signal between the first and second terminals, and correcting a distance measurement error by performing clock synchronization or frequency offset compensation between terminals based on the cooperation signal A wireless positioning ranging method between terminals. The method according to claim 1,
The step of determining whether the cooperative positioning request is,
An inter-terminal radio positioning ranging method for determining the cooperative positioning request when both the first and second channel quality values are smaller than the reference value. The method according to claim 1,
The cooperation request signal is,
A wireless positioning ranging method between terminals further comprising information on a transmission method of the cooperative signal and a channel condition for selection as the cooperative terminal together with the information for requesting the cooperative positioning. 4. The method according to claim 3,
The signal frame structure of the cooperation request signal includes a preamble, a header, and a payload section,
The information for requesting the cooperative positioning, the transmission method of the cooperative signal, and the channel conditions for selection as the cooperative terminal are,
An inter-terminal radio positioning ranging method sequentially inserted into the EXT region of the header. 4. The method according to claim 3,
The transmission method of the cooperation signal is,
A first transmission method in which the cooperative terminal broadcasts a beacon signal for clock synchronization between terminals to the vicinity; and
Inter-terminal radio including a second transmission method in which the cooperative terminal transmits, to the first and second terminals, the inter-terminal frequency offset information estimated through observation of the ranging frame signal of each of the first and second terminals, respectively Positioning ranging method. 6. The method of claim 5,
The transmission method of the cooperation signal is,
An inter-terminal radio positioning ranging method determined by the following equation based on the sequence length (N) and the operating bandwidth (B) of the preamble applied to the ranging frame signal:

Here, CoMODE denotes the determined transmission scheme, mode 0 denotes the first transmission scheme, mode 1 denotes the second transmission scheme, N _TH denotes a preset threshold sequence length, and B _TH denotes a preset threshold bandwidth. The method according to claim 1,
The step of selecting the cooperative terminal,
By analyzing the response signal, the radio positioning lane-terminal to navigate around the terminal satisfying the condition of Equation below in the wireless network in the candidate terminals (r _i) ranging by:

Here, Λ is a set of peripheral terminals satisfying {·},

is the channel quality with the first terminal estimated from the cooperation request signal received by the candidate terminal r _{i from the first terminal,}

is the channel quality with the second terminal estimated from the cooperation request signal received by the candidate terminal r _{i from the second terminal,}

denotes a reference channel quality value for selection of a cooperative terminal. In a wireless positioning ranging system between terminals using a cooperative terminal based on a wireless network system,
Each of the first and second channel quality values, which are channel quality values with the counterpart terminal estimated from the ranging request signal received through the counterpart terminal, are compared with a reference value, respectively, and whether or not a cooperative positioning request is made through a neighboring terminal according to the comparison result Determination, when the cooperative positioning request is determined, the first and second terminals each broadcast a cooperation request signal to one or more neighboring terminals, respectively, first and second terminals for receiving a response signal;
After receiving the cooperation request signal from the first and second terminals, the response signal is transmitted, and at least one neighboring terminal selectable as a cooperative terminal,
The first and second terminals are
Based on the response signal, a terminal existing in a common channel quality region between the first and second terminals among neighboring terminals is selected as a cooperative terminal and operates to transmit a cooperative signal, and ranging between the first and second terminals A wireless positioning ranging system for measuring a distance between terminals through transmission and reception of a frame signal, and correcting a distance measurement error by performing clock synchronization or frequency offset compensation between terminals based on the cooperation signal. 9. The method of claim 8,
The first terminal and the second terminal,
A wireless positioning ranging system for determining the cooperative positioning request when both the first and second channel quality values are smaller than the reference value. 9. The method of claim 8,
The cooperation request signal is,
A wireless positioning ranging system further comprising information on a transmission method of the cooperative signal and a channel condition for selection as the cooperative terminal together with the information for requesting the cooperative positioning. 11. The method of claim 10,
The signal frame structure of the cooperation request signal includes a preamble, a header, and a payload section,
The information for requesting the cooperative positioning, the transmission method of the cooperative signal, and the channel conditions for selection as the cooperative terminal are,
A radio positioning ranging system sequentially inserted into the EXT area of the header. 11. The method of claim 10,
The transmission method of the cooperation signal is,
A first transmission method in which the cooperative terminal broadcasts a beacon signal for clock synchronization between terminals to the vicinity; and
A radio positioning lane including a second transmission scheme in which the cooperative terminal transmits inter-terminal frequency offset information estimated through observation of the ranging frame signal of each of the first and second terminals to the first and second terminals, respectively gong system. 13. The method of claim 12,
The transmission method of the cooperation signal is,
A radio positioning ranging system determined by the following equation based on the operating bandwidth (B) and the sequence length (N) of the preamble applied to the ranging frame signal:

Here, CoMODE denotes the determined transmission scheme, mode 0 denotes the first transmission scheme, mode 1 denotes the second transmission scheme, N _TH denotes a preset threshold sequence length, and B _TH denotes a preset threshold bandwidth. 9. The method of claim 8,
The first terminal and the second terminal,
A wireless positioning ranging system that analyzes the response signal when the cooperative terminal is selected and searches for neighboring terminals satisfying the condition of the following equation among _{candidate terminals (r i ) in the wireless network:}

Here, Λ is a set of peripheral terminals satisfying {·},

is the channel quality with the first terminal estimated from the cooperation request signal received by the candidate terminal r _{i from the first terminal,}

is the channel quality with the second terminal estimated from the cooperation request signal received by the candidate terminal r _{i from the second terminal,}

denotes a reference channel quality value for selection of a cooperative terminal.

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