KR20040063250A - Wireless LAN transmitter - Google Patents

Abstract

PURPOSE: A wireless LAN repeater and its method are provided to remove a cause of oscillation in advance that can occur between an AP(Access Point) and a client station from mixing up signals. CONSTITUTION: When power is applied to start operation(S10), signals of an AP and client stations are received through an antenna(S20). The two signals are amplified through an LNA(Low Noise Amplifier) and then separated with the same power through an RF(Radio Frequency) splitter(S30). The two separated signals are mixed with signals introduced from low splitters in mixers and then outputted as IF(Intermediate Frequency) signals(S40). One of the IF signals is selected under the control of a microprocessor and outputted to a frequency mixer(S50). The frequency mixer mixes the selected IF signal and a local oscillation signal selected by a local oscillator switch and outputs an RF signal, and the RF signal is outputted to a circulator after passing through a band pass filter and a PA(Power Amplifier)(S60). The signal inputted to the circulator is transmitted only to a band pass filter and then transmitted wirelessly through the antenna(S70).

Description

Wireless LAN repeater and its method {Wireless LAN transmitter}

The present invention relates to the field of a local area network (LAN) repeater, and more specifically, to eliminate in advance the factors of oscillation that may occur by confusing signals between an access point and a client station. The present invention relates to a wireless LAN repeater and a method capable of efficiently performing wireless communication.

Wireless LAN provides the advantages of reliability, security, scalability, flexibility, ease of installation and maintenance, compared to wired LAN, which requires the use of wired cables by transmitting and receiving data through a medium called radio waves. At the same time, the performance and effectiveness of investment are excellent, and the demand in the Internet access service market is expected to grow rapidly, and it is expected to accelerate the mobile computing era.

Currently commercially available wireless LANs are classified into infrared and radio methods according to the medium used. The radio methods are broadly classified into spread spectrum and micro cellular methods.

The above-mentioned infrared ray system is an optical wave which is already used for a remote control such as a television or a VCR, and uses an infrared ray having a lower frequency than visible light. Since the infrared rays are much higher than the frequency of radio waves, they can provide abundant bandwidth, do not receive interference from other radio signals or neighboring cells, and do not leak internal information to the outside of the cell to maintain security. It does not need to be licensed, and it is possible to build a high-speed wireless LAN with a high transmission speed compared to spread spectrum LAN or narrowband microwave LAN with abundant bandwidth, and infrared devices are small in size and low in price. In addition, the power consumption is very low, there is an advantage to configure a compact device.

However, the above-mentioned infrared ray method requires an antenna to be installed on the ceiling to minimize the disturbance of a person or an object because of the non-transparent property of the infrared ray, which is similar to visible light and passes through the glass but does not penetrate an opaque obstacle such as a wall or a person. There are disadvantages.

On the other hand, the spread spectrum method of the radio method was originally developed during the Second World War with a military purpose in order to maintain the confidentiality of information, and transmits the radio signal to be transmitted over a wide band using a spreading code, It is a technique that the radio side or noise interference is excluded as much as possible by receiving it by converting it into the original frequency band at the receiving side.

In addition, the radio-based micro cellular method is a method used in a narrow band microwave LAN, and fixes a transmission / reception frequency and digitally divides the fixed frequency into a time division multiplexing (TDM) method. A narrowband cellular communication method for transmitting signals. This method uses the frequency of 18 GHz band in a similar way to the cellular method of providing current analog voice communication service, so it is unlikely that a signal penetrating from outside the building will interfere with the WLAN signal or the WLAN signal will exist outside the building. Security characteristics can be improved by having a strong characteristic against radio wave interference by a signal source, and there is an advantage in that multiple LANs can coexist in the same place by arranging cells using the same frequency so as not to overlap in the same place.

However, the micro-cellular method has a limitation in that the microwave can be bent along the structure or penetrates deep into the structure, such as a low frequency radio signal, and thus can be used only within the line of sight.

Therefore, the conventional WLAN requires the development of a highly efficient repeater in order to overcome the limitation of such a short transmission distance.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a conventional technical problem, and to efficiently perform wireless communication by eliminating factors of oscillation that may occur by confusing a signal between an access point and a client station. It is to provide a repeater and a method thereof.

1 is an installation configuration diagram of a wireless LAN repeater according to an embodiment of the present invention.

Figure 2 is a detailed circuit diagram of a wireless LAN repeater according to an embodiment of the present invention.

3 is an operation flowchart of a WLAN relay method according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100: access point 200: wireless LAN repeater

301 ~ 30n: Client station

As a means for achieving the above object, the configuration of the apparatus of the present invention includes an antenna for receiving or transmitting a signal, a circulator for providing a passage for transmitting and receiving a signal, and a signal of an access point and a client station. When received, they are divided into the same power to generate an intermediate frequency signal using a frequency mixer, and then select one of them and output it, and generate two local oscillator signals using two local oscillators, and the two local A local oscillator for selecting and outputting one of the oscillator signals and the intermediate frequency signal inputted from the receiver and the signal inputted from the local oscillator are mixed with each other to generate a radio frequency signal and output it to the circulator. It includes a transmitting end.

As a means for achieving the above object, the configuration of the method of the present invention comprises the steps of: receiving signals from an access point and a client station when the operation is started; distributing the received signals with the same power using a high frequency splitter; Converting the two divided signals into an intermediate frequency, generating two local oscillating signals, selecting one of the two signals converted into the intermediate frequency, and selecting one of the two local oscillating signals. And converting the selected signal into a radio frequency signal by mixing each other to transmit the selected signal through the antenna, and transmitting the converted signal through the antenna.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings in order to describe in detail enough to enable those skilled in the art to easily carry out the present invention. . Other objects, features, and operational advantages, including the object, operation, and effect of the present invention will become more apparent from the description of the preferred embodiment.

For reference, the embodiments disclosed herein are only presented by selecting the most preferred embodiment in order to help those skilled in the art from the various possible examples, the technical spirit of the present invention is not necessarily limited or limited only by this embodiment Rather, various changes, additions, and changes are possible within the scope without departing from the spirit of the present invention, as well as other equivalent embodiments.

The configuration of a wireless LAN repeater according to an embodiment of the present invention, as shown in Figure 2, the antenna 1 for receiving or transmitting a signal, and a circulator for providing a path for transmitting and receiving signals (3), when the signal of the access point and the signal from the client station are received, the receiver RX generates an intermediate frequency signal using a frequency mixer and selects and outputs one after selecting the same power, and two local oscillators. Two local oscillation signals are generated by using the signal output from the local oscillation stage LO and one of the two local oscillation signals, and the intermediate frequency signal input from the receiver RX. And a transmitting end RX for generating a radio frequency signal by mixing the local oscillating signals inputted from the local oscillating end LO and generating the radio frequency signal. By made.

According to an embodiment of the present invention, as shown in FIG. 3, the wireless LAN relaying method may include a step (S10) of starting operation and a signal of the access point 100 and the client stations 301 ˜ 30n. (S20) receiving (F1, F2), distributing the received signal with the same power using a high frequency splitter (S30), and converting the two divided signals into intermediate frequencies (S40) and Selecting one signal from two signals converted into an intermediate frequency and selecting one from two local oscillation signals (S50), and mixing the selected one signal with each other to transmit the selected signal through an antenna, And converting the signal converted into the F1 signal or the F2 signal (S60), transmitting the signal converted into the radio frequency signal through the antenna (S70), and terminating the operation (S80).

By the above configuration, the operation of the wireless LAN repeater and the method according to an embodiment of the present invention is as follows.

When the operation is started by applying power (S10), signals F1 and F2 of the access point 100 and the client stations 301 ˜ 30n are received through the antenna 1 (S20).

After the two signals pass through a band pass filter (BPF) (2), the two signals enter only the receiving end (RX) through the circulator (3) and cannot enter the transmitting end (TX). .

After the two signals input to the receiver RX are amplified by a low noise amplifier (LNA) 4, the signals are separated by the same power through the RF splitter 5 (S30). .

As described above, the two separated signals are mixed with the signals coming from the LO splitters 26 and 26 'in the frequency mixers 6 and 6', thereby intermediate frequency (IF) signals. It is output as (S40).

After the intermediate frequency signal, which is the output signal of the frequency mixers 6 and 6 ', passes through the band pass filters 7 and 7', and is amplified by the intermediate frequency amplifier IF Amp 8 and 8 ', The signals filtered in the SAW Filters 9, 9 'and thus filtered in the SAW Filters 9, 9' are passed through an intermediate frequency splitter 10, 10 'and two identical signals. Separated by (RX1, RX1 'and RX2, RX2').

One of the signals RX1 'and RX2' passing through the intermediate frequency splitters 10 and 10 'passes through a log amp 11 and 11' that converts an RF signal into a DC signal.

Some of the output signals of the log amplifiers 11 and 11 'pass through a low pass filter (LPF) 13 and 13', and then pass through a comparator 14 and 14 ', followed by an analysis. Input through the Analog Digital Converter (ADC) 15, 15 'is input to the input terminals X1 and X2 of the microprocessor.

In addition, some of the output signals of the log amplifiers 11 and 11 'are passed through an automatic gain controller (AGC) 12, 12' and a variable gain amplifier (VGA) (16, 16 '). ) Is input to the variable terminal of).

On the other hand, the other one of the signals (RX1, RX2) passing through the intermediate frequency splitter (10, 10 ') is input to the variable gain amplifier (16, 16'), input to the variable terminal of the variable gain amplifier (16, 16 ') The gain is controlled and output by the signal.

The output signals of the variable gain amplifiers 16, 16 'are amplified through the intermediate frequency amplifiers 17, 17', filtered by the saw filters 18, 18 ', and then again the intermediate frequency amplifiers 19, 19. Amplified through '), and then again through the intermediate frequency amplifiers 20 and 20', filtered through the saw filters 21 and 21 ', and then input to the IF switch 22. After that, a signal is selected by the control of the microprocessor and output to the frequency mixer 28 of the transmitting end TX (S50).

On the other hand, the local oscillation stage LO generates a signal for driving the frequency mixers 6 and 6 'of the receiving end RX and the frequency mixer 28 of the transmitting end TX under the control of the microprocessor.

The reference oscillator 23 of the local oscillator stage LO provides a reference frequency of the local oscillators 24, 24 ', and the signal of the local oscillators 24, 24' is a local oscillator amplifier (LO Amp). After the amplification through (25, 25 '), the local oscillator and the signal output for driving the frequency mixer (6, 6') of the receiving end (RX) through the LO splitter (26, 26 ') It is distributed as a signal output to the frequency mixer 28 of the transmitting end TX via the switch 27.

Two signals respectively inputted from the local oscillator splitters 26 and 26 'to the local oscillator switch 27 are selected by a micro-processor and a frequency mixer 28 of the transmitting end TX. Will be displayed.

In the frequency mixer 28 of the transmitting end TX, the intermediate frequency IF signal selected by the intermediate frequency switch 22 of the receiving end RX and the local oscillation signal selected by the local oscillator switch 27 of the local oscillating end LO are stored. When input, it is mixed and output as a radio frequency (RF) signal.

After the radio frequency signal TX1 or TX2 output from the frequency mixer 28 passes through the band pass filter 29 and is amplified through the power amplifier PA 30, the circulator 3 It is output as (S60).

In addition, the signal input to the circulator 3 is transmitted to the bandpass filter 2 only while being isolated from the receiving end RX by the circulator 3 and wirelessly transmitted through the antenna 1 (S70). ).

In order to adjust the output power transmitted through the antenna 1, some of the output signals of the power amplifier 30 of the transmitting end TX are fed back to the microprocessor via a power detector.

As described in the above embodiment, the present invention has the effect of efficiently performing wireless communication by eliminating factors of oscillation that may occur by confusing signals between the access point and the client station in advance.

Claims (2)

An antenna for receiving or transmitting a signal, A circulator for providing a path for transmission and reception of a signal, When receiving signals from the access point and the client station, the receiver receives the same power to generate an intermediate frequency signal using a frequency mixer, and then selects one of them and outputs it. A local oscillator generating two local oscillator signals using two local oscillators, selecting one of the two local oscillator signals, and outputting the selected one; And a transmitting end generating a radio frequency signal by mixing the intermediate frequency signal input from the receiving end with the signal input from the local oscillating end and outputting the generated radio frequency signal to the circulator. Receiving a signal from an access point and a client station when the operation is initiated; Distributing the received signal with the same power using a high frequency splitter; Converting the two divided signals to an intermediate frequency, Generating two local oscillation signals, Selecting one of the two signals converted to the intermediate frequency and one of the two local oscillating signals, Converting one selected signal into a radio frequency signal by mixing with each other for transmission through an antenna; And transmitting the signal converted into the radio frequency signal through an antenna.