KR100438065B1 - Appliance for radio frequency of Road Side Equipment of Dedicated Short Range Communication - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the application of a PLL type capable of performing a channel scan on a local oscillation device in a near field wireless communication base station of an intelligent transportation system. A high frequency switch for selecting a path according to a transmission and reception mode; A receiving unit for receiving the received high frequency signal as a near field radio frequency signal, mixing the local oscillation signal, converting it into an intermediate frequency, and demodulating the received data; A transmitter which modulates the transmission data into a local oscillation signal and then amplifies and outputs the power through the high frequency switch; It is characterized in that it comprises a local oscillator for generating a transmission and reception local transmission signal of the short-range wireless communication band by using the second harmonic component of the frequency generated by applying the PLL method on a single path.

According to the present invention, by applying a local oscillator having a PLL scheme on a single path, by using the second harmonic component of the PLL oscillation frequency to synchronize data transmitted and received in the transmission and reception local oscillation signal, the channel The present invention provides a short range wireless communication base station that is easy to scan and change.

Description

High frequency device of near field communication base station {Appliance for radio frequency of Road Side Equipment of Dedicated Short Range Communication}

According to the present invention, in the local oscillation apparatus of a short range wireless communication base station, a local oscillation signal of a short range wireless communication band can be generated by using a second compensation high frequency component of a PLL frequency with a temperature compensation crystal oscillator and a PLL (Phase Lock Loop) module. The present invention relates to a high frequency device of a short range wireless communication base station.

ITS (Intelligent Transport System) is a new transportation system that improves the mobility, stability, efficiency and the traffic environment by integrating the existing transportation system with advanced technologies such as information communication, electronics, control, and computers. It is aimed at reducing congestion, reducing traffic accidents, expanding the use of public transportation, and reducing logistics costs.

The new Dedicated Short Range Communication (DSRC), which is introduced to provide such intelligent transportation system services, is a system that bidirectionally communicates with a roadside base station located at a roadside and a vehicle terminal mounted on a vehicle.

The short range wireless communication means is a small output device supporting the TDMA / TDD scheme of the 5.8 GHz band having a communication distance of 100M or less and a transmission rate of 1 Mbps. It accommodates all ITS services.

1 is a block diagram of a high frequency device of a conventional short-range wireless communication base station.

Referring to FIG. 1, a high frequency switch 110 for switching a transmission mode and a reception mode path when communicating with a vehicle terminal through an antenna 100, and a frequency received from the high frequency switch 110 in a reception mode as an intermediate frequency. A receiver 120 for converting and demodulating a data signal, a transmitter 130 for modulating transmission data and outputting the modulated data through the high frequency switch 110, and frequency tuning of the receiver 120 and the transmitter 130 during data transmission and reception. It consists of a local oscillator 140 for outputting a local outgoing signal for.

Here, the receiver 120 includes a first bandpass filter 121 for filtering a 5.8 GHz band of a reception frequency, and a low noise amplifier (LNA) for amplifying a low noise signal of the filtered frequency signal (LNA). 122, a frequency converter 123 for mixing the output frequency of the low noise amplifier 122 with a local oscillation signal to convert the intermediate frequency, a second band pass filter 124 for filtering the intermediate frequency band, and An intermediate frequency amplifier 125 for amplifying the intermediate frequency signal, and a demodulator 126 for demodulating the data signal from the amplified intermediate frequency signal.

The transmitter 130 includes a data filter 131 for filtering data into a predetermined band signal, an amplitude sequence keying (ASK) modulator 132 for modulating the filtered data signal into a local oscillation signal, and the ASK. And a third bandpass filter 133 for filtering the modulated signal to the 5.8 GHz band, and a power amplifier 134 for power amplifying the signal filtered by the third bandpass filter 133.

The local oscillator 140 may include a first dielectric resonator oscillator (DRO) generating a reception frequency of 5.8 GHz and a local oscillation signal to the frequency converter 123 by amplifying the reception frequency. A second driving amplifier 142 for outputting a signal, a second dielectric resonance oscillator 143 for generating a transmission frequency of 5.8 GHz, and amplifying the generated transmission frequency and outputting the local oscillation signal to the ASK modulator 132. It consists of a second drive amplifier (144).

Referring to the accompanying drawings, a high frequency device of a conventional short-range wireless communication base station as described above is as follows.

First, in the transmission mode, the high frequency switch 110 is switched to the receiver side, and when a signal transmitted from the vehicle terminal is received by the antenna 100, the received signal (5.8 GHz) is output to the receiver 120.

The receiver 120 mixes the reception frequency with the local oscillation signal to make the intermediate frequency IF and demodulates the received data.

To this end, the first bandpass filter 121 of the receiver 120 filters the received frequency to the 5.8 GHz band and removes other band signals. The low noise amplifier 122 amplifies low noise to improve noise characteristics, and the frequency converter 123 converts the frequency output from the low noise amplifier (LNA) 122 into an intermediate frequency by mixing with a local oscillation signal. The two band pass filter 124 filters only the intermediate frequency band. The intermediate frequency amplifier 125 amplifies the filtered intermediate frequency and the demodulator 126 demodulates the received data signal from the intermediate frequency.

In the transmission mode, the data filter 131 of the transmitter 130 filters the input data signal, and the ASK modulator 132 modulates the data signal with a local oscillation signal at a frequency of 5.8 GHz and uses a third band pass. The filter 133 filters the required 5.8 GHz band among the frequencies modulated by the ASK modulator 132, and amplifies and outputs the power to the power amplifier 134.

Then, the transmission signal output from the power amplifier 134 of the transmitter 130 is transmitted to the terminal through the antenna 100 in the switching switching of the high frequency switch 110 to work in accordance with the transmission mode.

On the other hand, the local oscillator 140 generates transmit and receive local oscillation signals according to the transmission and reception mode, and outputs them to the receiver 120 and the transmitter 130, respectively. The first dielectric resonance oscillator (DRO) 141 is 5.8 GHz band. Generates a reception frequency (5.87 GHz), and the driving amplifier 142 amplifies the reception frequency and outputs the received local oscillation signal to the frequency converter 123.

In addition, the second dielectric resonator oscillator (DRO) 143 generates a transmission frequency (5.8 GHz) of 5.8 GHz, and the second driving amplifier 144 amplifies the transmission frequency and then uses an ASK modulation unit (ASK) as a local oscillation signal. 132) to modulate the transmission data.

However, in the related art, the dielectric resonator oscillators 141 and 143 generating oscillation frequency in the local oscillator 140 are installed in different transmission and reception paths and generate 5.8 GHz band, but the dielectric resonator oscillators 141 and 143 have their volume. Large, only factory-set fixed channels are available, and channel scans and changes are not possible, so only fixed channels are always available.

In addition, the size of the high frequency part (RF part) is increased due to the external size of the dielectric resonator oscillators 141 and 143, and it acts as an important factor that separates the control part from the high frequency part.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to provide a high frequency device having a local oscillation unit in which a temperature compensated crystal oscillator and a PLL module are installed on a single path.

It is also an object of the present invention to provide a high frequency device of a short range wireless communication base station, which can obtain a short range wireless communication band by filtering a second harmonic component of a PLL frequency.

1 is a block diagram showing a high frequency device of a conventional short-range wireless communication base station.

2 is a block diagram illustrating a high frequency device of a short range wireless communication base station according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100,200 ... antenna 110,210 ... high frequency switch

120,220 ... receiver 130,230 ... transmitter

140,240 ... local oscillator 141,143 ... DRO

142,144,244 ... Amplifier 241 ... Temperature Compensated Crystal Oscillator

242 ... PLL module 243 ... band pass filter

In order to achieve the above object, a high frequency device of a short range wireless communication base station according to an embodiment of the present invention,

A high frequency switch for selecting a path according to a transmission and reception mode when communicating with a vehicle terminal;

A receiving unit for receiving the received high frequency signal as a near field radio frequency signal, mixing the local oscillation signal, converting it into an intermediate frequency, and demodulating the received data;

A transmitter which modulates the transmission data into a local oscillation signal and then amplifies and outputs the power through the high frequency switch;

It is characterized in that it comprises a local oscillator for generating a transmission and reception local transmission signal of the short-range wireless communication band by using the second harmonic component of the frequency generated by applying the PLL method on a single path.

Preferably, the local oscillator comprises, on a single path, a crystal oscillator for generating a reference frequency for PLL operation, a PLL module for operating at the PLL reference frequency and generating transmit and receive frequencies with a fast locking time, and the generated oscillator. A bandpass filter for filtering a second harmonic component of the PLL frequency to output a short range wireless communication band, a drive amplifier for amplifying a required frequency of the bandpass filtered short range wireless communication band, and transmitting and receiving in conjunction with the high frequency switch And an output switch outputting the local oscillation signal.

Hereinafter, with reference to the accompanying drawings as follows.

2 is a block diagram of a high frequency device of a short range wireless communication base station according to an exemplary embodiment of the present invention.

2, a high frequency switch 210 for switching a transmission / reception path of short-range wireless data transmitted and received to and from a vehicle terminal through an antenna 200, and converting a received high frequency signal into an intermediate frequency by a local oscillation signal and receiving data. A receiver 220 for demodulating the signal; A transmission unit 230 for modulating the transmission data into a local oscillation signal, amplifying the power to a high frequency of 5.8 GHz, and outputting the power to the high frequency switch 210; A local oscillation unit 240 is configured to output a transmission / reception local oscillation signal using a temperature compensation crystal oscillator 241, a PLL module 242, and a bandpass filter 243 according to a transmission and reception mode on a single path.

Here, the local oscillator 240 is a temperature compensation crystal oscillator (TCXO, 241) for generating a PLL reference frequency in the transmission and reception mode, and a PLL module 242 for generating a transmission frequency and a reception frequency by the PLL reference frequency. And a bandpass filter 243 for filtering the 5.8 GHz band, which is the second harmonic component of the generated frequency, a drive amplifier 244 for amplifying the bandpass filtered required frequency, and a drive amplifier 244. And an output switch 245 for outputting the amplified transmission and reception local oscillation signals according to the transmission / reception mode.

Referring to the accompanying drawings, a high frequency device of a short range wireless communication base station according to an exemplary embodiment of the present invention will be described.

Referring to FIG. 2, the high frequency switch 210 converts a signal transmitted through the antenna 200 and a received signal according to a transmission / reception mode to the receiver 220 and the transmitter 230 for short range wireless communication with the vehicle terminal. Connected.

In the reception mode, a transmission signal of the vehicle terminal is received through the antenna 200, the received high frequency signal is applied to the receiver 220 through the high frequency switch 210, and the receiver 220 receives the first high frequency signal. The bandpass filter is performed by the bandpass filter 221 and low noise amplified by the low noise amplifier 222.

The frequency converter 223 mixes the received high frequency signal with the local oscillation frequency to convert the intermediate frequency, and the intermediate frequency converted by the frequency converter 233 is filtered by the bandpass filter 234 to filter only the intermediate frequency component. After amplification by the intermediate frequency amplifier 235, the demodulator 236 demodulates the received data (1 Mbps).

In the transmission mode, the transmission data is modulated to the local oscillation frequency in the transmission unit 230 and then transmitted to the vehicle terminal through the high frequency switch 210 and the antenna 200.

The data filter 231 of the receiver 230 filters digital data (1 Mbps) to be transmitted, and the ASK modulator 232 modulates the transmitted data into the local oscillation signal, and then, the third band pass filter 233. ) Bandpass filters the modulated frequency to the 5.8 GHz band, and the power amplifier 234 power amplifies the bandpass filtered frequency and outputs the amplified frequency to the high frequency switch 210.

On the other hand, the local oscillator 240 generates a local oscillation signal for tuning to the transmission and reception signals of the transmission and reception unit 220, 230, respectively generates a transmission and reception local oscillation signal according to the transmission and reception mode on a single path.

The local oscillator 240 includes a temperature compensated crystal oscillator (TCXO) 241, a phase lock loop (PLL) module 242, a band pass filter (BPF) 243, a drive amplifier 244, and an output switch 245. It is composed.

The temperature compensated crystal oscillator 241 is a crystal application and generates a reference frequency for operating the PLL, and the PLL module 242 compares the phase of the PLL reference frequency and the oscillation frequency and uses the difference to generate the frequency. Find and output the desired transmit and receive frequencies respectively. The PLL module 242 exists on the transmit and receive paths TX and RX for TDD communication in bidirectional communication.

At this time, the PLL module 242 implements a PLL locking time within 30 us when the operating frequency is changed (transmitted and received). That is, in the TDD scheme, frequency generation to different transmission and reception frequencies can be quickly changed by the fast locking time.

The PLL compares the phase of the reference frequency of the reference oscillator and the oscillation frequency of the voltage control oscillator (VCO) and uses the difference to find the frequency using the difference, which is lock time and phase noise. The relationship between noise and frequency shift is inversely related to each other. In other words, if the PLL lock time is shortened in an optimal state, the phase noise characteristic deteriorates proportionally, and the larger the amount of change in frequency, the longer the PLL lock time becomes.

In this case, when the PLL reference frequency is generated, the bandpass filter 243 may filter the second harmonic of the harmonic component of the reference frequency of 2.9 GHz to obtain a signal of a desired short range wireless communication band.

The signal filtered by the band pass filter 243 is amplified by a driving amplifier 244 to a required frequency of a short range wireless communication band, and then transmitted and received by the output switch 245 to the receiver 220 and the transmitter 230. It is output as a local oscillation signal for tuning.

As described above, the present invention applies the PLL type to the base station for the ITS short-range wireless communication so that not only the fixed channel shipped from the factory but also the channel scan is possible, so that the channel can be easily changed and various services can be supported. In this case, the base station channel can be remotely controlled.

Here, the transmission frequency is about 70 MHz away from the reception frequency, and a 70 MHz frequency change occurs during transmission and reception.

As such, the crystal oscillator 241 and the PLL module 242 are positioned on a single path, respectively, and the second harmonic component of the PLL frequency generated from the PLL module 242 can be filtered to create a frequency of a short range wireless communication band. This generates the 5.8 GHz band tuning frequency required for short-range wireless communication.

In addition, since the PLL method is used for the local generator in the high frequency unit for the ITS roadside base station, the channel scan is possible, and thus the channel can be easily changed, and the base station channel installed in the center can be remotely controlled and various services are provided.

As described above, according to the local oscillation apparatus of the short-range wireless communication base station according to the present invention, by applying the PLL type on a single path, the channel scan and the channel change in the base station installed at a lower price than the conventional DRO type are easy, It is effective to cope with service.

In addition, the PLL module generates transmit and receive frequencies, and by filtering the second high frequency component of the frequency, it is possible to generate local oscillation signals in the short range wireless communication frequency band, thereby eliminating the need for a high frequency amplifier and multiplier when generating 5.8 GHz band. Therefore, it is possible to reduce parts and miniaturize high frequency devices in the PLL type.

Claims (3)

A high frequency switch for selecting a path according to a transmission and reception mode when communicating with a vehicle terminal; A receiving unit for receiving the received high frequency signal as a near field radio frequency signal, mixing the local oscillation signal, converting it into an intermediate frequency, and demodulating the received data; A transmitter which modulates the transmission data into a local oscillation signal and then amplifies and outputs the power through the high frequency switch; A local oscillation unit generating and outputting a transmission or reception local transmission signal of a short range wireless communication frequency band using a second harmonic component of a frequency generated by a PLL scheme according to a transmission or reception mode on a single path; The local oscillator comprises: a crystal oscillator for generating a reference frequency for PLL operation on a single path; A PLL module operating at the PLL reference frequency and generating transmit and receive frequencies with a fast locking time, a bandpass filter for filtering a second harmonic component of the generated PLL frequency to output a short range wireless communication band, and the bandpass And a drive amplifier for amplifying at a required frequency of the filtered short range wireless communication band, and an output switch for outputting as a transmit or receive local oscillation signal in association with the high frequency switch . delete The method of claim 2, The PLL module generates a transmission frequency and a reception frequency by a fast locking time according to a transmission / reception mode, and sets the locking time to 30 uS or less.