KR100634979B1 - Ultra wide band ranging device and method thereof - Google Patents

Abstract

An ultra wideband ranging device and a method thereof are provided to enable 1 bit analog-digital converters to quantize data, enable an accumulator to accumulate the quantized data at regular intervals, and enable a timing estimator to estimate the first arrival time by using a critical value, thereby efficiently estimating the first arrival time in a situation that a receiving time is vague. An ultra wideband ranging device comprises the followings: an antenna(10); a low noise amplifier(11); an analog energy detector(12); a DC(Direct Current)-offset estimator(13) which calculates DC-offset energy corresponding to detected energy; a window bank(14) which stores the energy, detected by the analog energy detector(12), as data; plural 1bit analog-digital converters(15) which apply the DC-offset energy to a critical value and quantize the data stored in the window bank(14); a window buffer(16) which stores the quantized data at regular intervals; an accumulator(17) which accumulates the quantized data stored in the window buffer(16); and a timing estimator(18) which estimates the first arrival time from the accumulated data.

Description

Ultra Wide Band Ranging Device And Method

1 is a block diagram showing an ultra-wideband ranging apparatus according to a first embodiment of the present invention.

FIG. 2 illustrates estimating initial arrival time information using the ultra-wideband ranging apparatus of FIG. 1. FIG.

3 is a block diagram illustrating an ultra-wideband ranging apparatus according to a second embodiment of the present invention.

4A and 4B illustrate estimating initial arrival time information using the ultra-wideband ranging apparatus shown in FIG. 3.

5 is a diagram showing the limit of theoretical initial arrival time information according to bandwidth;

6 illustrates a preamble structure for ranging in LR-WPAN.

7 is a diagram illustrating a waveform from which a DC-offset component has been removed.

8 illustrates waveforms of signals accumulated at intervals between pulses of a signal received after passing through a 1-bit analog-to-digital converter.

9 illustrates threshold setting according to SNR.

10 is a view showing the performance of the ranging method according to the cumulative number of intervals between pulses of the received signal according to the SNR change in the CM1 environment.

11 is a view showing the performance of the ranging method according to the cumulative number of intervals between pulses of the received signal according to the SNR change in the CM8 environment.

FIG. 12 is a diagram illustrating the performance of a ranging method when a ranging error adaptation is applied according to a cumulative number of intervals between pulses of a signal received in a CM1 environment.

FIG. 13 is a diagram illustrating the performance of a ranging method when a ranging error adaptation is applied according to a cumulative number of intervals between pulses of a signal received in a CM8 environment.

      <Description of Symbols for Main Parts of Drawings>

10, 20: antenna 11, 21: low noise amplifier

12, 22: analog energy detector 13, 23: DC-offset estimator

14, 24: Windows banks 15, 25: Multiple 1-bit ADCs

16, 26: window buffer 17, 27: accumulator

18, 28: timing estimator 29: comparator

The present invention relates to an ultra-wideband ranging apparatus and method, and more particularly to a non-interfering ultra-wideband ranging apparatus and method using an analog energy window bank and a 1-bit analog-to-digital converter.

Recently, a wireless communication technology that utilizes a high frequency band of 3 to 10 GHz ultra wide band (UWB-Ultra Wide Band) has been developed. Ultra Wideband Communication (UWB) is a technology that exchanges data using microwaves, which consumes less power and has a short transmission distance of about 10m. It is attracting attention as a new wireless communication technology.

Ultra-wideband means that the frequency band used is very wide. The Federal Communications Commission (FCC) defines the ultra-wideband communication as a communication method that has a bandwidth of 20% or more of the center frequency or 500MHz or more. Ultra-wideband communication can deliver ultra-low power radio signals simultaneously on all frequencies using very short pulses of a trillionth of a second.

That is, the ultra wideband communication may have a smaller strength of the transmission signal as the bandwidth is wider. Therefore, this ultra-wideband communication system is characterized by being able to transmit a small power signal in a wide band and to collect the wide band signal and reproduce it as a high power signal. This ultra-wideband communication system is robust to multipath fading because it generates and transmits a very short pulse of nsec unit such as an impulse, and provides a very accurate position recognition function. This location recognition is applicable to applications such as material management, medical imaging, and collision avoidance. Ultra-wideband communications can also transmit and receive data using frequencies already in use by other systems. The signal of the ultra wideband communication can make the power density value very small by using the wide frequency band, so that even if it is superimposed on the frequency in which other communication signals exist, it hardly interferes. That is, the ultra-wideband communication uses a very low spectral power density at the same level as the noise of a conventional wireless system, so that the frequency can be shared and used without interfering with existing communication systems such as mobile communication, broadcasting, and satellite.

Accordingly, ultra-wideband communication is the next generation transmission technology to complete a home network or a wired / wireless electric facility network, rather than a general broadcasting or mobile communication system, and has been in the spotlight as a technology capable of preoccupying the ubiquitous market. In Korea, the importance of the home network sector is selected as one of the next 10 new growth engines as a core technology for ubiquitous environment.

In such a ubiquitous environment using ultra-wideband communication, an apparatus and method for recognizing a location of an object are required. In order to accurately recognize a location of an object, obtaining accurate ranging information becomes an essential factor.

These ranging information acquisition methods are different depending on whether the system is synchronized. That is, in the case of a synchronous system, the ranging information acquisition method can be ranging through one-way transmission, but an initial installation cost increases because an absolute index such as a global positioning system (GPS) is required. In the case of the asynchronous system, ranging information is obtained by obtaining round trip time information through two-way. Such synchronous and asynchronous systems require the first arrival time information to obtain ranging information, and multipath, white noise (AWGN), interference between different systems, Incorrect synchronization, jitter, etc., causes the ranging performance to deteriorate rapidly. Such deterioration of ranging performance is further exacerbated in a non-LOS multipath environment, which makes it impossible to track actual first arrival time information. This inability to track the first arrival time information is a factor that drastically degrades the ranging performance.

Accordingly, an object of the present invention is to provide initial arrival time information in a loss or non-loss multipath environment using a plurality of 1-bit analog-to-digital converters that require a low sampling rate in a non-interfering ultra-wideband method using energy detection. The present invention provides a non-interfering ultra-wideband ranging apparatus and method for estimating initial arrival time information using a threshold value after accumulating a predetermined amount of signals at intervals between pulses.

Another object of the present invention is to quantize the received time information using a 1-bit analog-to-digital converter in the non-interfering ultra-wideband communication scheme, and accumulate the quantized results at regular intervals, and then use a threshold. After the estimated initial arrival time information and the received signal is delayed for a predetermined time, quantized using a 1-bit analog-to-digital converter, the quantized results are accumulated at regular intervals, and then estimated using a threshold. The present invention provides a non-interfering ultra-wideband ranging apparatus and method capable of efficiently estimating initial arrival time information in a situation where reception time is ambiguous by selecting a specific value by comparing first arrival time information with each other.

Another object of the present invention is to adjust the variation of the SNR and the interval between the pulses and the pulses on the two channels proposed by the international standardization group IEEE 802.15.4a, so that the ranging performance in the non-interfering ultra-wideband communication is most effectively distributed. To provide an ultra-wideband ranging apparatus and method that can estimate the optimal performance based on these conditions.

In order to achieve the above object, an ultra-wideband ranging apparatus according to an embodiment of the present invention includes an antenna for receiving a signal transmitted from a transmitting end; A low noise amplifier for amplifying low noise among signals received by the antenna; An analog energy detector for detecting energy of the amplified signal at regular intervals; A DC-offset estimator for calculating a DC-offset energy corresponding to the detected energy; A window bank for storing energy detected by the analog energy detector as data; A plurality of 1-bit analog-to-digital converters that apply the DC-offset energy to a threshold to quantize data stored in a window bank; A window buffer for storing the quantized data at predetermined intervals; An accumulator for accumulating quantized data stored in the window buffer; And a timing estimator for estimating first arrival time information from the accumulated data.

The DC-offset estimator estimates the DC-offset energy from the energy detected by the analog energy detector using an analog low pass filter.

The window bank is composed of a plurality of non-overlapping window buffers.

The accumulator accumulates data having the same address value in each window buffer among a plurality of window buffers arranged at regular intervals and supplies the accumulated data to the timing estimator.

The timing estimator determines first arrival time information by comparing the accumulated data with a predetermined threshold and selecting a first value among the threshold values or more.

The output of the analog-to-digital converter is characterized in that either one or -1.

An ultra-wideband ranging apparatus according to an embodiment of the present invention includes an antenna for receiving a transmission signal from a transmitter; A low noise amplifier for amplifying the signal received by the antenna; An analog energy detector for detecting energy of the amplified signal at a predetermined interval; A DC-offset estimator for calculating a DC-offset energy corresponding to the detected energy; A window bank for storing energy detected by the analog energy detector as data; A plurality of 1-bit analog-digital converters for quantizing each data stored in the window bank; A window buffer having a first buffer for storing quantized data at predetermined intervals and a second buffer for storing quantized data delayed for a period of time; A comparator for selecting a buffer having a large value by comparing the data stored in the first and second buffers; An accumulator for accumulating data stored in a buffer selected by the comparator to generate cumulative data; And a precision timing estimator for estimating the first arrival time information from the accumulated data.

The first buffer stores sample values quantized by the 1-bit analog-to-digital converter at intervals between pulses of the received signal.

The second buffer may store sample values delayed by a time corresponding to half of the length of the first buffer at intervals between pulses of the received signal.

The comparator compares data stored in each of the first buffer and the second buffer with a predetermined threshold, selects data having a value greater than or equal to a threshold, and compares data corresponding to the first address of each buffer among the selected data. It is characterized in that for supplying the stored data of the large data buffer to the accumulator.

Ultra-wideband ranging method according to an embodiment of the present invention comprises the steps of receiving a signal transmitted from a transmitting end to low noise amplification; Detecting energy of the amplified signal; Storing the energy detected by the energy detector as data; Quantizing the stored data according to a threshold; Storing the quantized data in a window buffer at regular intervals; Accumulating quantized data stored in the window buffer at each predetermined interval for each address; And comparing the accumulated data with a predetermined threshold value and estimating the first arrival time information when the accumulated data is greater than or equal to a threshold value and the first data.

The ultra-wideband ranging method according to the present invention further includes calculating a DC-offset energy corresponding to the detected energy, and applying the DC-offset energy to a threshold of the quantization step.

Quantizing each of the stored data may include storing the quantized data in a first buffer at a predetermined interval; And storing the quantized data in the second buffer at predetermined intervals delayed by a time corresponding to half of the first buffer length.

And after storing the quantized result in the window buffer at a predetermined interval, comparing the first buffer and the second buffer with each other to compare the buffer having a large first address value.

Other objects and features of the present invention in addition to the above object will be apparent from the description of the embodiments with reference to the accompanying drawings.

1 illustrates an apparatus for non-interfering ultra-wideband ranging according to an embodiment of the present invention.

Referring to FIG. 1, an apparatus for ultra-wideband ranging according to an embodiment of the present invention includes an antenna 10 for receiving an ultra-wideband communication signal and a low noise amplifier for amplifying low noise among the signals received by the antenna 10. (LNA) 11, an analog energy detector 12 for detecting the energy of the amplified signal at regular intervals, a DC-offset estimator 13 for calculating a DC-offset energy corresponding to the detected energy, A window bank 14 for storing energy detected by the energy detector 12 as data, and a plurality of 1-bit analog-digital quantizing data stored in the window bank 14 by applying the DC-offset energy to a threshold. A converter (ADC) 15, a window buffer 16 for storing quantized data at regular intervals, an accumulator 17 for accumulating quantized data stored in the window buffer 16, and an initial diagram from the accumulated data. It comprises a timing estimator 18 for estimating the time information.

The low noise amplifier 11 amplifies low noise among the received signals received by the antenna 10 and supplies it to the analog energy detector 12.

The analog energy detector 12 calculates, at a predetermined interval, an energy signal having a DC-offset component of a predetermined level or more corresponding to the received signal amplified by the low noise amplifier 11 and the DC-offset estimator 13 and the window bank 14. Each).

The DC-offset estimator 13 estimates the DC-offset information from the energy signal supplied from the analog energy detector 12 by using an analog low pass filter. The DC-offset information is used as threshold information of the 1-bit analog-to-digital converter to output a signal from which a certain amount of DC-off is removed to the window buffer 16.

The window bank 14 consists of a plurality of non-overlapping window buffers, each window buffer size serving as an element that determines the resolution of the ranging. In other words, the smaller the window buffer size, the more precise and accurate ranging results can be obtained.

The plurality of 1-bit analog-to-digital converters 15 operate at a low sampling rate and are configured in a chain form at intervals of several nsec between the analog-to-digital converters 15. As a result, the output of the multiple 1-bit analog-to-digital converters 15 results in fast sampled sample values. That is, as the number of analog-to-digital converters 15 is provided, the use of the low-speed analog-to-digital converter 15 is possible.

The window buffer 16 stores, as data, sample values quantized into one bit output from the one bit analog-to-digital converters 15.

The accumulator 17 supplies the timing estimator 18 with accumulated data accumulated in data stored in a buffer having the same address value in each window buffer 16 among the plurality of window buffers 16 arranged at regular intervals. .

The timing estimator 18 determines the first arrival time information by comparing the data accumulated by the accumulator 17 with a preset threshold and selecting a first value among the threshold values or more.

A method of estimating initial arrival time information using an apparatus for non-interfering ultra-wideband ranging according to an embodiment of the present invention having such a structure will be described.

Prior to describing a method for estimating initial arrival time information according to an embodiment of the present invention, the non-interfering ultra-wideband ranging apparatus according to an embodiment of the present invention transmits multiple paths between fixed transceivers at equal intervals. It is assumed that the same application is applied to the received pulses. Accordingly, by accumulating a large number of sample values at equal intervals, the difference between the noise component and the signal component is increased to estimate the time information on the weakly received first arrival component.

First, a transmission signal transmitted at a PRI interval at a transmitter may be expressed as Equation 1.

Where p (t) is one ultra-wideband pulse, T _f is the interval between pulses (PRI), and M is the total number of repetitions of the pulse. The received signal is composed of directly received signal components such as a loss signal, reflected and received signal components, noise and interference components. Therefore, the reception signal r (t) according to the transmission signal may be represented by Equation 2.

Where a _d and τ _d represent the intensity and arrival time of the LOS component, respectively, and a _n and τ _n represent the intensity and arrival time of the reflected components, and n (t) means white noise with an average of 0. do. The energy signal for each T _f can be calculated by adding the received signal squared during that time, and the energy signal e (t) can be expressed by Equation 3 below.

On the other hand, the energy component of the white noise follows a Chi-square distribution having a specific DC-offset energy according to statistical and mathematical characteristics. This DC-offset energy can be roughly obtained through an analog low pass filter, and the DC-offset energy is used as a reference threshold of a 1-bit analog-to-digital converter. Here, the output y _DC-offset (t) of the analog low pass filter may be expressed as Equation 4.

Where * represents the convolution operator and h implies the impulse response of the _LPF (t) analog low pass filter. On the other hand, the corresponding energy values for the interval of each frame divided into N slots can be represented by Equation 5.

는 아날로그 저역 필터 출력과 직류-옵셋 에너지와의 차를 통해 에너지 신호의 직류-옵셋 에너지를 줄일 수 있게 되며 결과 적으로 직류-옵셋 에너지가 줄어든 에너지 신호

는 수학식 6과 같이 나타내어 진다.Energy signal in equation (5)

The difference between the analog low pass filter output and the dc-offset energy can reduce the dc-offset energy of the energy signal, resulting in an energy signal with a reduced dc-offset energy.

Is expressed as in Equation 6.

This DC-off energy reduced signal is sampled by the 1-bit analog-to-digital converter and the quantized sample value at this time can be expressed as shown in Equation (7).

As a result, the quantized sample value of the received signal is output using the result value calculated by Equations 1 to 7. The first arrival time information is estimated by applying the quantized sample value to the first arrival time information processing structure shown in FIG. In FIG. 2, M means the number of pulse repetitions, that is, the number of window buffers having N lengths. Each of the first to Mth window buffers (1st to Mth) stores N binary data, and the binary data stored in the first to Mth window buffers are accumulated in each buffer unit to accumulate an accumulator block. Block). The accumulator block supplies this binary data to the original arrival time estimation block (Estimation of ToA), thereby estimating the initial arrival time information. At this time, as shown in Equation 8, the first arrival time information ToA is obtained by selecting an index of a value corresponding to the first among values above a predetermined threshold value.

In this case, ToA denotes first arrival time information, t denotes a time at the present time, T _win denotes a time interval of each window, and T _start denotes a start time of transmission.

The ultra-wideband ranging apparatus and method according to the first embodiment of the present invention for estimating the first arrival time information in this manner is weak by collecting and quantizing a signal at a predetermined pulse interval, and then accumulating and calculating the quantized result. First arrival time information can be obtained from one signal. That is, the 1-bit analog-to-digital converter 15 according to the first embodiment of the present invention quantizes the signal to 1 or -1 around the threshold 0 so that the received signal is quantized regardless of the signal strength. Accordingly, by accumulating the sample values stored in the buffer several times, it is possible to process the weak initial arrival time information in the non-roth environment.

However, in the ultra-wideband ranging apparatus and method according to the first embodiment of the present invention, when a received signal is accumulated at a predetermined interval in a situation where a reception point of a signal is unclear, a maximum access delay component reflected by an object is buffered. There is a problem in that it is not possible to obtain an accurate minimum arrival component stored at the front of the. Accordingly, the ultra-wideband ranging apparatus and method according to the second embodiment of the present invention will propose a method for solving the timing error problem caused by the ambiguity of the reception time.

3 illustrates a non-interfering ultra-wideband ranging apparatus according to a second embodiment of the present invention.

Referring to FIG. 3, the non-interfering ultra-wideband ranging apparatus according to the second embodiment of the present invention provides an antenna 20 for receiving an ultra-wideband communication signal and low noise for amplifying low noise among the signals received by the antenna 20. An amplifier (LNA) 21, an analog energy detector 22 for detecting the energy of the amplified signal at regular intervals, a DC-offset estimator 23 for calculating a DC-offset energy corresponding to the detected energy, A window bank 24 for storing the energy detected by the analog energy detector 22 as data, and a plurality of 1 bits for quantizing each data stored in the window bank 24 by applying the DC-offset energy to a threshold. A window buffer 26 having an analog-to-digital converter 25, a first buffer 26a for storing quantized data at predetermined intervals, and a second buffer 26b for storing quantized data delayed for a predetermined period of time; The data stored in the buffer selected by the comparator 29 and the comparator 29 for selecting a buffer having a large index by comparing the values of the first and second buffers 26a and 26b in the dough buffer 26. An accumulator 27 for accumulating and a precision timing estimator 28 for estimating initial arrival time information from the accumulated data are provided.

Here, the non-interfering ultra-wideband ranging apparatus according to the second embodiment of the present invention is compared with the window buffer 26, the comparator 29 and the non-interfering ultra-wideband ranging apparatus according to the first exemplary embodiment of the present invention. Except for the fine timing estimator 28, the configuration is the same except for the window buffer 26, the comparator 29 and the fine timing estimator 28, and thus the description thereof will be omitted.

The window buffer 26 includes a first buffer 26a for storing sample values quantized in one bit and a second buffer 26b for quantizing the delayed signal and storing the sample values output as quantized data.

The first buffer 26a stores sample values quantized into 1 bit as quantization data in the interval between pulses, that is, the PRI interval.

The second buffer 26b stores the sample values delayed by N / 2 as the delayed quantization data as PRI intervals compared to the sample values stored in the first buffer 26a. Where N represents the length of the buffer. The interval of PRI is equal to the length divided by the interval of one window bank 23.

The comparator 29 selects values higher than or equal to a predetermined threshold from the first buffer 26a and the second buffer 26b, and compares the address address positions of the buffers corresponding to the first of the selected output values with each other. The value stored in the large buffer is supplied to the accumulator 27.

The precision timing estimator 28 accumulates any one of the quantized data and the delayed quantized data stored in the buffer selected by the comparator 29 among the first and second buffers 26a and 26b and compares it with a predetermined threshold value. From the first arrival time information is obtained.

A method of obtaining first arrival time information of a non-interfering ultra-wideband ranging apparatus according to a second embodiment of the present invention having such a structure will be described.

The method for acquiring the first arrival time information of the non-interfering ultra-wideband ranging apparatus according to the second embodiment of the present invention is to obtain the first arrival time information of the non-interfering ultra-wideband ranging apparatus according to the first embodiment of the present invention. Equations 1 to 8 are applied equally from the method to calculate the output values of each step, and the output values of the data stored in the first and second buffers 26a and 26b and the first arrival information time estimation accordingly are shown in FIGS. 4b and 9 and 10 will be described. That is, the method for acquiring the first arrival time information of the non-interfering ultra-wideband ranging apparatus according to the second embodiment of the present invention includes the first arrival time information of the non-interfering ultra-wideband ranging apparatus according to the first embodiment of the present invention. The same applies to the quantization step using a 1-bit analog-to-digital converter compared to the acquisition method.

FIG. 4A shows the result when the quantized sample values are stored in the T _f interval through the 1-bit analog-to-digital converter 25, and FIG. 4B shows the result when the sample values are stored in the buffer after the T _f / 2 delay. Indicates. That is, in the case of the two buffers 26a and 26b, the buffer incorrectly determines the first arrival delay component in FIG. 4A. Therefore, in the ultra-wideband ranging method according to the second embodiment of the present invention, the first arrival time information estimation method compares the address of the address of the buffer corresponding to the first of the above threshold values from two buffers. The first arrival time information is obtained by selecting a buffer having a large index of as a buffer in which the ambiguity at the reception time is solved and accumulating the quantized data of the selected buffer in which the ambiguity is solved. Here, a method of acquiring the first arrival time information through the threshold in the buffer storing the sample values after the T _f / 2 delay is shown in Equation (9).

Here, ToA _buffer2 represents a buffer in which sample values are accumulated after T _f / 2 delay.

On the other hand, when the first arrival time information is a buffer in which sample values are accumulated after a delay of T _f / 2 is selected, the first arrival time information should be calculated including a time component corresponding to T _f / 2 as shown in Equation 10. do.

Here, ToA represents first arrival time information, ToA _buffer1 represents first arrival time information calculated from the first buffer 26a, and ToA _buffer2 represents first arrival time information calculated from the second buffer 26b. In this case, the comparator 29 compares the first address values of the first buffer 26a and the second buffer 26b with each other, so that the values stored in the first buffer 26a and the second buffer 26b are not calculated. Instead, the first arrival time information can be estimated by accumulating only the stored values of the selected buffer.

CRLB (Cramer-) used when the threshold for acquiring the first arrival time information according to the first and second embodiments of the present invention estimated by the above method, that is, the threshold of ranging performance, is an uncomfortable amount and the sample size is sufficiently large. We will model it theoretically using Rao Lower Bound.

The limit of the reliable delay estimation for the first arrival time information of the present invention using the CRLB can be expressed by Equation (11).

는 최초 도착 시간 정보 추정값의 변이량을 나타내며, β_f 는 수신 신호의 대역폭을, 그리고 SNR은 에너지와 노이즈의 비율인 Eb/No를 나타낸다. 이러한 수학식 11을 이용하여 레인징 거리에 대한 CRLB는 수학식 12와 같이 나타낼 수 있다.here,

Denotes the amount of variation of the estimated time of arrival information, β _f denotes the bandwidth of the received signal, and SNR denotes Eb / No, which is a ratio of energy and noise. Using the equation 11, the CRLB for the ranging distance may be expressed as shown in Equation 12.

Variation of initial arrival time information estimate × C (speed of light = 3 × 10 ⁸ m / sec)

Based on Equations 11 and 12, when the SBR is linearly increased, the CRLB for each ranging distance is shown in FIG. 5.

Referring to FIG. 5, as the bandwidth increases, the accuracy of ranging is significantly increased, and when the bandwidth is 2 GHz, the theoretical limit range appears to be less than about 5 cm between 10 dB and -10 dB.

The performance of the ranging apparatus and the method according to the first and second embodiments of the present invention are described in terms of two channel models presented by the IEEE 802.15.4a Task Group, that is, CM1 (Residential LOS environments) and CM8 (Industrial NLOS environments). An experimental result of experimenting with 100 channels per channel model will be described with reference to FIGS. 6 to 13. 7 and 11 are diagrams illustrating the performance of the ranging apparatus and method according to the first embodiment of the present invention, and FIGS. 12 and 13 illustrate the ranging apparatus and method according to the second embodiment of the present invention. The figure which shows the performance. In addition, for the performance experiment of the ranging apparatus and method, the preamble structure presented in the IEEE 802.15.4 standard shown in FIG. 6 is adopted, and the total length of the preamble is 4 bytes, of which 3 bytes For the purpose of the lane measurement, one byte is set to use as information for determining the threshold value for demodulation for noise measurement.

FIG. 6 is a diagram illustrating LR-WPAN, a preamble structure presented in the IEEE 802.15.4 standard.

Here, Tp is the width of the pulse, PRI (= T _f ) is the width between the pulse and the pulse, one symbol (T _b ) is generated two pulses. The 3 bytes used for ranging are set to "1" to distinguish between signal components and noise components by maximizing the cumulative number within a predetermined range. In addition, the experimental parameters are set as shown in Table 1. That is, in order to prevent Interband Interference (IPI) due to multi-path, ultra-wideband pulses having a pulse width of 2 nsec with a center frequency of 4.1 GHz and a bandwidth of 2 GHz, PRI is a channel model defined by the IEEE 802.15.4a Task Group. Set to 400 nsec considering root mean square (RMS) delay spread.

parameter Setting value Tp (pulse width) 2ns Tf (pulse width) 400 ns Tb (pulse width) 800 ns Number of pulse repetitions per symbol 2 Bandwidth 2 GHz Sample cycle 0.025ns Number of bits used for ranging 24bits Modulation OOK

FIG. 7 shows waveforms corresponding to a portion of a signal obtained by subtracting a DC-off component, which is output information of an analog low pass filter, from an energy signal obtained through an analog energy detector. As shown in FIG. 7, it can be seen that the DC-offset component is reduced.

Here, each sample on the x side represents energy corresponding to 80 sample values (= T _p ), and eventually, the length of PRI composed of energy sample values becomes 200 (= T _f / T _p ).

FIG. 8 shows the result of storing quantized sample values in a buffer in a channel environment in which LOS exists and accumulating them in a PRI interval.

Here, when the 1-bit analog-to-digital converter determines that the signal components are all 1, the signal is increased by the maximum cumulative number, and when the 48 pulses are used as shown, the maximum value becomes 48. On the other hand, if the noise component is assumed to be white noise with a mean value of 0, the energy component of this method follows the Chi-square distribution, and the distribution of the noise component when the DC-offset is reduced at this time is also almost zero. As a result, noise components cancel each other out and accumulate to zero when accumulated several times.

9 shows a threshold value according to SNR to obtain an original arrival component.

In order to set the threshold, the parameter is set to 48 iterations of PRI in non-LOS environment, and SNR is -6, -3, 0dB, respectively, and the first arrival component after passing through analog-to-digital converter is 1 If it is determined that 48 is 100%, increase the threshold value by 5% interval from 0 to 50% to set an appropriate threshold value. As shown in FIG. 9, the error with the first arrival component is minimized at about 25-30%.

10 is a diagram showing the performance results of the proposed ranging apparatus and method according to the cumulative number of PRI while changing the SNR from 6dB to -6dB in the CM1 environment with LOS. However, it is assumed that the reception time point is known. Here, the y-axis represents the probability that a ranging error occurs within 1m. As shown in FIG. 10, it can be seen that the performance of the ranging apparatus and method improves as the PRI increases.

11 is a diagram showing the performance results of the proposed Ranging technique according to the cumulative number of PRIs while changing the SNR in a CM8 environment with Non-LOS. However, it is assumed that the reception time point is known. In the non-LOS environment, the weak first arrival signal component degrades slightly compared to the performance result in the LOS environment.

12 and 13 illustrate a ranging apparatus and method according to a change in SNR and a cumulative number of PRIs when applying a ranging error adaptation method that proposes a ranging error generated due to ambiguity of a reception time in the environment of CM1 and CM8, respectively. Show performance results. The results represented by circles in FIG. 12 indicate that the performance is very deteriorated when the performance is compared with other graphs of FIGS. 12 and 13 according to the ranging error generated due to ambiguity of the reception time. However, when the ranging error adaptation scheme is applied, the ranging performance is almost similar to that shown in FIGS. 12 and 13. 12 and 13, the ranging performance is improved as the number of PRIs increases.

As described above, the ultra-wideband ranging apparatus and method according to an embodiment of the present invention uses a plurality of 1-bit analog-to-digital converters that require a low sampling rate using energy detection. As a method for estimating initial arrival time information in an environment, an effect of providing a non-interfering ultra-wideband ranging apparatus and method capable of estimating initial arrival time information by using a threshold value after accumulating a predetermined amount at intervals between pulses There is.

The ultra-wideband ranging apparatus and method according to another embodiment of the present invention quantizes the received signal by using a 1-bit analog-to-digital converter, and accumulates the quantized result at a predetermined interval, and then thresholds the initial arrival time information. Delay the received signal with the estimated time of arrival and the received signal for a certain period of time, and then quantized using a 1-bit analog-to-digital converter, the quantized results are accumulated at a predetermined interval, and then using a threshold By comparing the estimated first arrival time information with each other and selecting a specific value, it is possible to efficiently estimate the first arrival time information in a situation where the reception time is ambiguous.

Another object of the ultra-wideband ranging apparatus and method according to another embodiment of the present invention is to provide a method for non-interfering ultra-wideband communication by controlling a change in SNR and a change in pulse-to-pulse spacing on two channels presented in IEEE 802.15.4a. It is effective to estimate a condition in which the ranging performance is most effectively distributed, and to provide an ultra-wideband ranging apparatus and method capable of exhibiting optimal performance based on these conditions.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (21)

An antenna for receiving a signal transmitted from a transmitting end; A low noise amplifier for amplifying low noise among signals received by the antenna; An analog energy detector for detecting energy of the amplified signal at regular intervals; A DC-offset estimator for calculating a DC-offset energy corresponding to the detected energy; A window bank for storing energy detected by the analog energy detector as data; A plurality of 1-bit analog-to-digital converters that apply the DC-offset energy to a threshold to quantize data stored in a window bank; A window buffer for storing the quantized data at predetermined intervals; An accumulator for accumulating quantized data stored in the window buffer; And And a timing estimator for estimating first arrival time information from the accumulated data. The method of claim 1, wherein the DC-offset estimator, An ultra-wideband ranging apparatus, wherein the energy detected from the analog energy detector is estimated by using an analog low pass filter. The method of claim 1, wherein the window bank, An ultra-wideband ranging device comprising a plurality of non-overlapping window buffers. The accumulator of claim 1, And accumulating data having the same address value in each window buffer among a plurality of window buffers arranged at regular intervals, and supplying accumulated data to the timing estimator. The method of claim 1, wherein the timing estimator, And determining first arrival time information by comparing the accumulated data with a preset threshold and selecting a first value among threshold values or more. The method of claim 1, wherein the output of the analog-to-digital converter An ultra-wideband ranging device, characterized in that any one of 1 or -1. The method of claim 1, wherein the transmission signal, Transmit signal s (t); p (t) is one ultra-wideband pulse; T _f is the interval between pulses; And When M indicates the total number of repetitions of the pulse,

Ultra-wideband ranging apparatus characterized in that. The method of claim 1, wherein the received signal, R (t), a _d is the strength of the LOS component, τ _d is the arrival time of the LOS component, a _n is the intensity of the reflected components, τ _n is the arrival time of the reflected components, n (t) is white noise with an average of 0,

Ultra-wideband ranging apparatus characterized in that. The method of claim 1, wherein the energy detected at regular intervals by the analog energy detector, Energy signal e (t), If the interval is T _f ,

Ultra-wideband ranging apparatus characterized in that. The method of claim 1, wherein the one slot energy detected by the analog energy detector in the frame consisting of N slots, If the energy signal is e (t)

Ultra-wideband ranging device characterized in that. The method of claim 1, wherein the DC-offset energy, * Is a convolution operator; h _LPF (t) For impulse response of analog low pass filter e (t) * h _LPF (t) ultra-wideband ranging device characterized in that. The method of claim 1, wherein the first arrival time information, ToA first arrival time information; The time at the present time is t; The time interval for each window is T _win ; The quantized value of the signal obtained by removing the DC-offset energy from the energy detected by the energy detector is

; The start time of the transfer is T _start ; If the predetermined threshold is Threshold,

Ultra-wideband ranging apparatus characterized in that. An antenna for receiving a transmission signal from a transmitting end; A low noise amplifier for amplifying the signal received by the antenna; An analog energy detector for detecting energy of the amplified signal at a predetermined interval; A DC-offset estimator for calculating a DC-offset energy corresponding to the detected energy; A window bank for storing energy detected by the analog energy detector as data; A plurality of 1-bit analog-to-digital converters for quantizing each data stored in the window bank; A window buffer having a first buffer for storing quantized data at predetermined intervals and a second buffer for storing quantized data delayed for a period of time; A comparator for selecting a buffer having a large value by comparing the data stored in the first and second buffers; An accumulator for accumulating data stored in a buffer selected by the comparator to generate cumulative data; And a precision timing estimator for estimating initial arrival time information from the accumulated data. The method of claim 13, wherein the first buffer, And storing sample values quantized by the 1-bit analog-to-digital converter at intervals between pulses of the received signal. The method of claim 13, wherein the second buffer, And storing sample values delayed by a time corresponding to half of the length of the first buffer at intervals between pulses of the received signal. The method of claim 13, wherein the comparator, Compare the data stored in each of the first buffer and the second buffer with a predetermined threshold value to select data having a value greater than or equal to a threshold value, and compare the data corresponding to the first address of each buffer among the selected data. An ultra-wideband ranging device for supplying stored data of a large buffer to an accumulator. The method of claim 13, wherein the first arrival time information calculated by the second buffer is: ToA, first arrival time information by the second buffer; The time at the present time is t; The time interval for each window is T _win ; The quantized value of the signal obtained by removing the DC-offset energy from the energy detected by the energy detector is

; The start time of the transfer is T _start ; The length of the window buffer is N; The number of window buffers is M; If the predetermined threshold is Threshold,

Ultra-wideband ranging apparatus characterized in that. Receiving a signal transmitted from a transmitting end and amplifying low noise; Detecting energy of the amplified signal; Storing the energy detected by the energy detector as data; Quantizing the stored data according to a threshold; Storing the quantized data in a window buffer at regular intervals; Accumulating quantized data stored in the window buffer at each predetermined interval for each address; And And comparing the accumulated data with a predetermined threshold value and estimating the first arrival time information when the accumulated data is greater than or equal to a threshold value and is the first data. The method of claim 18, Calculating a DC-offset energy corresponding to the detected energy; And applying the DC-offset energy to the threshold of the quantization step. 19. The method of claim 18, wherein quantizing each stored data comprises: Storing the quantized data in the first buffer at regular intervals; And And storing the quantized data in the second buffer at predetermined intervals delayed by a time corresponding to half of the first buffer length. The method of claim 20, And storing the quantized result in a window buffer at a predetermined interval, and comparing the first buffer and the second buffer with each other to compare a buffer having a large first address value. .

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