KR20070064742A - Low capacity uwb communication system and a method thereof - Google Patents

Abstract

A low capacity UWB(Ultra Wide Band) communication system and a communication method thereof are provided to be suitable for a low power wireless sensor network of a low capacity data transmission by applying pulse with a very small width and a low duty cycle. A low capacity UWB communication system includes a transmitter(10) and a receiver. The transmitter(10) mixes digital data and an impulse control signal which are inputted and transmits a mixed digital data and impulse control signal according to an impulse generated by an impulse generator. The receiver restores the digital data by detecting digital data signals from the impulse received from the transmitter(10).

Description

Low capacity UWB communication system and a method thereof

1 is a block diagram schematically showing a low capacity UWB communication system according to the present invention;

2 is a block diagram of a data packet for asynchronous transmission;

3 is a schematic view of the impulse generator of FIG.

4 is a diagram illustrating a transmission impulse waveform and a delay response waveform in the measured time domain;

5 is a diagram illustrating a simulator of an impulse reception signal detector of FIG. 1;

6 is a view showing a simulation result of a received waveform detection of an impulse signal;

7 is a view showing a timing result obtained by converting a measured impulse transmission waveform and a received signal into a digital signal;

8 is a flowchart illustrating a communication method by the low capacity UWB communication system of FIG. 1, and

9 is a view schematically showing a low-capacity UWB communication system application CANVAS system.

Explanation of symbols on the main parts of the drawings

10 transmitter 11: level converter

13: controller 15: impulse generator

20: Receiver 21: LNA & Filter

23 amplifier 25 signal detector

27: signal restoration controller 29: level converter

The present invention relates to a UWB (Ultra Wide-Band) communication system and a communication method thereof, and more particularly, to a low-capacity UWB communication system and a communication method of the pulse method applicable to the field of low-power wireless sensor network of low-capacity data transmission will be.

UWB technology was first developed as a special-purpose military technology, but since 1994, many research areas have been released from military security and are emerging as new technology fields with great market potential. UWB technology is a high-speed, short-range wireless communication system, a localizer that can measure distances to targets with high accuracy, remote sensing to detect the location of objects or people in underground buildings or buildings, It is a high technology with a wide range of applications such as high resolution radar.

The Federal Communications Commission (FCC) recently issued a 1st Report & Order, which stipulates the limited use of UWB technology as an unlicensed wireless device. Research to commercialize low-capacity sensor networks is actively underway. The Institute of Electrical and Electronics Engineers (IEEE) 802.15 working group for wireless personal area network (TGG4a) standardizes the use of UWB technology as the physical layer of low-capacity, location-based wireless personal area networks (WPANs). Currently, the main technologies based on the UWB Impulse Radio method for communication and location application and the 2.4GHz Chirp Radio method for data communication are adopted. The technical editor (TE) is under review for the detailed technical adoption.

Most UWB receiver structures that are generally considered have a high speed mixer section in the RF stage, which is typically considered in wireless communication, to obtain a correlation result by multiplying a pulse signal received through an antenna with a specific template reference signal. Therefore, the baseband unit determines the received pulse signal information through the high speed A / D converter.

However, in order to accurately determine the information of a received pulse, an accurate correlation result of the received pulse must be obtained, which poses an implementation problem that requires consideration of complex high speed synchronization algorithms and sophisticated analog synchronization circuits. This, in turn, increases the hardware complexity of the entire UWB system, making it difficult to apply to low power applications.

The present invention was made to solve the above problems, and an object of the present invention is to provide a pulsed low capacity UWB communication system and a communication method applicable to a low power wireless sensor network field of low capacity data transmission.

According to an aspect of the present invention, there is provided a low-capacity UWB communication system comprising: a transmitter configured to mix input digital data and an impulse control signal and transmit the mixed data according to an impulse generated by an impulse generator; And a receiver which detects the digital data signal from the impulse received from the transmitter and restores the digital data.

Here, the transmission unit, a level converter for inverting the input digital data; And a controller for generating an impulse control signal for a predetermined time each time the input digital data signal is changed, and transmitting a signal mixed by the controller through a broadband wireless antenna according to an impulse generated by the impulse generator. It is desirable to.

At this time, the controller continuously outputs a low value when the idle state (no signal) is received with respect to the signal received from the level converter, and when the rising edge occurs, the controller outputs the high signal for a predetermined time. After outputting (High) to return to low, and falling edge (Falling Edge) occurs, it is preferable to return to low after outputting the high for the predetermined time.

The receiver may include: an LNA & filter for catching and filtering an operating point and a matching point such that a noise figure (NF) is low with respect to an impulse signal received from the transmitter; An amplifier for amplifying the signal filtered by the LNA &filter; A signal detector for detecting a digital data signal from the signal amplified by the amplifier; A signal restoration controller for restoring original digital data from the signal detected by the signal detector; And a level converter for inverting and outputting the signal restored by the signal restoration controller.

In this case, it is preferable that the signal restoration controller outputs a high signal with respect to the signal received from the signal detector in a state where an impulse signal is not received, and outputs an inverted signal after a predetermined time when an edge occurs. Do.

In addition, it is preferable that the transmitter and the receiver transmit and receive data asynchronously and in an amplitude modulation scheme.

The transmitter may transmit the impulse data in a packet unit including a start bit, a data bit, a parity bit, and a stop bit to the receiver.

On the other hand, the low-capacity UWB communication system according to the present invention, the step of inverting the input digital data; Generating an impulse control signal of a predetermined time each time the input digital data signal is changed; Transmitting a signal mixed by the impulse control signal generating step through a broadband wireless antenna according to an impulse generated by an impulse generator; Catching and filtering an operating point and a matching point so that NF is low with respect to the received impulse signal; Amplifying the filtered signal; Detecting a digital data signal from the amplified signal; Restoring original digital data from the detected signal; And inverting and outputting the restored signal.

Thus, the low capacity UWB communication system according to the present invention can be applied to the field of low power wireless sensor network of low capacity data transmission.

Hereinafter, a low capacity UWB communication system and a communication method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram schematically illustrating a low capacity UWB communication system according to the present invention. Referring to the drawings, a low capacity UWB communication system includes a transmitting end 10 and a receiving end 20. Here, the transmitter 10 includes a level converter 11, a controller 13, and an impulse generator 15, and the receiver 20 includes an LNA & filter 21, an amplifier 23, and a signal detector 25. , A signal recovery controller 27, and a level converter 29. The figure shows a case where data is transmitted and received between the transmitting end 10 of one low capacity UWB communication system and the receiving end 20 of another low capacity UWB communication system.

The level converter 11 inverts the signal and sends it out. The input serial communication data signal having a range of + 11V to -11V is converted into a transmission signal for generating an impulse through a commercially programmable Complex Programmable Logic Device (CPLD) chip. Invert the signal and send it out.

The controller 13 performs transmission signal conversion. The controller 13 includes a pulse generator (not shown) for converting the input binary data value into an encoded signal for transmission by an impulse and decoding again, and an asynchronous transmission signal converter (not shown). Here, the transmission signal converter is designed using a commercially programmable chip such as CPLD. Transmitter includes other digital signal input / output interface, 11.0592MHz oscillator, DC + 5V input, D-type 9Pin Serial Connector, main components of RF Connector and other peripherals. The power source uses DC + 5V It is designed to supply power.

The CPLD receives a signal from the level translator 11 and continuously outputs a low (0) when in an idle state (no signal). Then, when a rising edge occurs, the CPLD receives about 904 ns. Output high (1) at + 5V level and return to low (0) .If falling edge occurs, output high (1) for the same time and then go to low (0). To return. That is, whenever the input data signal is changed, a pulse of a predetermined time (904 ns) is generated. This signal is used as an input to the impulse generator 15 and transmits impulse data through a broadband wireless antenna. At this time, the data input sequence to be transmitted is composed of a packet unit of 11 bits in total, and is composed of a start bit, a data bit, a parity bit, and a stop bit as shown in FIG.

In the case of a low capacity UWB transmission system, a sufficiently low data rate of several kbps is transmitted, so it is more efficient to transmit and receive data asynchronously than the synchronous transmission method. Therefore, as shown in the transmission packet of FIG. 2, simply indicating the start and end flags and transmitting 8 bits of data including parity information solves an unexpected timing problem in actual implementation and greatly reduces the complexity of the circuit.

Ultra-wideband communication is defined as a communication method that transmits the maximum spectrum using a band of at least 500 MHz. In particular, the UWB scheme designed according to the present invention collects these pulses and transmits the information by using pulse characteristics of a very small width and a low duty cycle as the pulsed UWB, and the transmission scheme is based on an amplitude modulation scheme.

The amplitude modulation method, also called an AM (Amplitude Modulation) method, refers to a modulation method of changing the amplitude of a carrier wave according to the amplitude of a signal wave. That is, the amplitude modulation method refers to a modulation method in which the amplitude of the carrier wave is changed according to the amplitude of the signal wave when music, voice, video, etc. are converted into electrical signals and sent to a remote place by wireless or wired. In general, an amplitude modulated wave is generated by passing a signal wave through a modulator together with a carrier wave having a higher frequency than the signal. At this time, the amplitude of the carrier is constant, but the modulated one changes in accordance with the change of the signal. When receiving, this modulated wave is passed through a demodulator (detector), whereby the amplitude-changed portion is removed to reproduce the original signal.

3 is a view schematically showing the impulse generator 15 of FIG. Referring to the figure, the impulse generator 15 is composed of a short pulse generator (Short Pulse Generator) and an impulse generator (Impulse Generator), by using this to create a mono pulse of 2ns or less pulse width and transmit.

4 is a diagram illustrating a transmission impulse waveform and a delay response waveform in the measured time domain. In the case of the transmission impulse waveform, the digital data trigger signal generated from the short pulse generator generates an impulse according to the change of the signal through the impulse generator module. The delay response waveform is the actual response waveform that is accepted by the CPLD to recognize the transmitted impulse signal.

The impulse signal received by the receiver 20 passes through two broadband antennas through a free space channel, and forms a pulse form as a result of two differentiation. At this time, the impulse signal received by the receiving end 20 has a very low power level under the influence of attenuation and noise. The low noise amplifier (LNA) & filter 21 catches and filters the operating point and the matching point so that the noise figure (NF) is low, and the amplifier 23 amplifies the filtered signal.

The signal detector 25 is designed as an integrator with a specific fast step recovery diode and an RC constant value.

5 shows a functional block diagram of the entire low-capacity UWB communication system. Its structure consists of a transmitter consisting of mixing input digital data and an impulse control signal (actual mixing can be implemented in a very simple single pulse method as shown in FIG. 3), an impulse generator for RF propagation, and ultra-wideband It consists of an analog medium unit including a transmitting and receiving antenna, and a receiving unit comprising a low noise amplifier, a low pass filter and a signal detector.

6 illustrates an operation simulation result obtained when operating the low capacity UWB communication system of FIG. 5. That is, the input signal data waveform of FIG. 6 is mixed with an imp waveform which is an impulse control signal, and then transmits an impulse signal tx on the RF space. The received signal through the ultra wideband transmit / receive antenna is represented by rx0 waveform, and it is represented by rx waveform through low noise amplifier and low pass filter. Finally, the digital data signal transmitted through the signal detector can be obtained as shown in the out_data waveform. As such, the simulator of the impulse analog transceiver for the low capacity ultra wide band communication system according to the present invention can be designed and verified using an ADS tool.

The signal restoration controller 27 performs reception signal conversion. In order to recover the original signal from the received signal passing through the broadband antenna and the signal detector 25, conversion of the received signal must be performed. The reception signal converter (not shown) in the signal restoration controller 27 is composed of CPLD XC9536, 11.0592MHz Oscillator, DC + 5V input, D-type 9Pin Serial Connector, main components of RF Connector and other peripheral devices. The power supply uses DC + 5V and is designed for independent power supply.

The reception signal converter receives a signal from the signal detector 25. When the impulse signal is not received, the reception signal converter outputs a high (1) signal and then, when a rising edge occurs, a two clock time (11.0592 MHz) is used. The inverted signal is output after approximately 180 ns = (1 / Freq. X 2) The inverted signal consists of a serial data signal and is inverted after changing the voltage level from 0 V to +10 V in the level converter 29 for input. Figure 7 is a signal conversion timing diagram for a received pulse, and it can be seen that the signal data is converted according to the pulse at the time of reception. Shows that the information is restored.

8 is a flowchart illustrating a communication method using the low capacity UWB communication system of FIG. 1. With reference to the drawings will be described in detail a communication method of a low capacity UWB communication system according to the present invention.

The level converter 11 of the transmitter 10 inverts and transmits the input serial communication data having a range of + 11V to -11V (S101).

The inverted data is converted into a signal for generating an impulse through a programmable CPLD chip of the controller 13. The CPLD continues to output low when no signal is present, then returns to low after output of + 5V for about 904ns when a rising edge occurs. In addition, when the falling edge is generated, the CPLD outputs high for the same time and then returns to low. That is, the controller 13 generates a pulse of a predetermined time 904 ns every time the input data signal is changed (S103). This signal is used as an input of the impulse generator 15, and transmits impulse data through a broadband wireless antenna (S105).

The LNA & filter 21 of the receiver 20 catches and filters the operating point and the matching point such that the NF is low for the impulse signal received from the transmitter 10, and the amplifier 23 amplifies the filtered signal (S107). ).

After the input signal data is mixed with the impulse control signal by the transmitter 10 and transmitted as an impulse signal, tx, in an RF space, a received signal passing through an ultra wideband transmit / receive antenna is represented by an rx0 waveform as shown in FIG. It passes through a low noise amplifier, low pass filter and appears as an rx waveform. From this signal, the signal detector 25 detects a digital data signal as shown in the out_data waveform (S109).

The signal restoration controller 27 performs reception signal conversion in order to recover the original signal from the reception signal passed through the broadband antenna and the signal detector 25 (S111). At this time, the reception signal converter in the signal restoration controller 27 outputs a high signal while the impulse signal is not being received, and then outputs an inverted signal after 2 clock times when a rising edge is generated. The inverted signal is composed of a serial data signal, and is output in an inverted state after changing the voltage level from 0 V to +10 V in the level converter 29 for input (S113).

9 is an application canvas system implemented by a low capacity UWB communication system according to the present invention. Canvas programming uses the National Instruments LabVIEW tool, which draws on the canvas of multiple receiver windows at a distance greater than a certain distance when the sender draws a picture or text on the canvas.

In order to reduce power consumption, the wireless asynchronous UWB communication system according to the present invention does not consider a high speed correlator and a high speed A / D converter of an impulse signal, and selects a transmission data packet and an asynchronous reception method suitable for a low power low capacity transmission purpose. Binary data is a non-return-to-zero (NRZ) signal that has designed a simple digital transceiver that transmits an impulse with a pulse width less than 2ns, detects it, and converts it. Based on the designed low-capacity UWB communication system, Peer-to-Peer transmission and reception of up to 115kbps was confirmed, and a low-power wireless canvas system was implemented.

Although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and the present invention is not limited to the specific embodiments of the present invention without departing from the spirit of the present invention as claimed in the claims. Anyone skilled in the art can make various modifications, as well as such modifications are within the scope of the claims.

According to the present invention, a UWB communication system suitable for a low power wireless sensor network field of low capacity data transmission by applying a transmission data packet and an asynchronous transmission / reception scheme suitable for a low power low capacity transmission purpose, and applying a pulse having a very small width and low duty cycle Can be provided.

Claims (9)

A transmitting unit for mixing the input digital data and the impulse control signal and transmitting the mixed data according to the impulse generated by the impulse generator; And And a receiver which detects a digital data signal from an impulse received from the transmitter and restores the digital data. The method of claim 1, wherein the transmitting unit, A level converter for inverting input digital data; And A controller for generating an impulse control signal of a predetermined time each time the input digital data signal is changed, And a signal transmitted by the controller through a broadband wireless antenna in accordance with an impulse generated by the impulse generator. The method of claim 2, The controller continuously outputs a low level when the controller receives an idle state (no signal) with respect to the signal received from the level converter. Low output UWB communication system, characterized in that to return to low after outputting a falling edge (Falling Edge) occurs, after outputting a high for the predetermined time. The method of claim 1, wherein the receiving unit, An LNA & filter which catches and filters an operating point and a matching point such that a noise figure (NF) is low with respect to an impulse signal received from the transmitter; An amplifier for amplifying the signal filtered by the LNA &filter; A signal detector for detecting a digital data signal from the signal amplified by the amplifier; A signal restoration controller for restoring original digital data from the signal detected by the signal detector; And And a level converter for inverting and outputting a signal restored by the signal restoration controller. The method of claim 4, wherein The signal restoration controller outputs a high signal to a signal received from the signal detector in a state where an impulse signal is not received, and outputs an inverted signal after a predetermined time when an rising edge occurs. Low-capacity UWB communication system. The method of claim 1, The transmitting unit and the receiving unit low capacity UWB communication system, characterized in that for transmitting and receiving data asynchronously. The method of claim 1, The transmitter and the receiver is a low capacity UWB communication system, characterized in that for transmitting and receiving data in an amplitude modulation scheme. The method of claim 1, And the transmitting unit transmits impulse data of a packet unit including a start bit, a data bit, a parity bit, and a stop bit to the receiving unit. Inverting the input digital data; Generating an impulse control signal of a predetermined time each time the input digital data signal is changed; Transmitting a signal mixed by the impulse control signal generating step through a broadband wireless antenna according to an impulse generated by an impulse generator; Catching and filtering an operating point and a matching point so that NF is low with respect to the received impulse signal; Amplifying the filtered signal; Detecting a digital data signal from the amplified signal; Restoring original digital data from the detected signal; And And inverting the restored signal to output the restored signal.

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