KR100349659B1 - Wireless Local Area Network RF Front-End Transceiver - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a radio frequency (RF) front-end transceiver.

2. The technical problem to be solved by the invention

An object of the present invention is to provide a wireless LAN RF front-end transmitting and receiving device using a power down mode in order to stop a transmission function during a reception mode operation in implementing a wireless RF RF front-end transmitting and receiving device on one board.

3. Summary of Solution to Invention

According to an aspect of the present invention, there is provided a wireless LAN RF front-end transceiver, comprising: local signal generating means for generating first and second local signals of a specific frequency band; First upconverting means for upconverting a data signal input from a baseband to an intermediate frequency signal using a first local signal generated from said local signal generating means; Second upconverting means for synthesizing the intermediate frequency signal upconverted by the first upconverting means with the second local signal generated from the local signal generating means and upconverting the RF signal into an RF signal; First downconverting means for downconverting the received RF data signal into an intermediate frequency signal synthesized with a second local signal generated from the local signal generating means; Second downconverting means for downconverting the intermediate frequency signal downconverted by the first downconverting means into a baseband signal using the first local signal generated from the local signal generating means; And transmission / reception mode selection means for selecting a transmission / reception mode through the antenna.

4. Important uses of the invention

The present invention is used in a wireless LAN RF system.

Description

Wireless LAN Front End Transceiver {Wireless Local Area Network RF Front-End Transceiver}

The present invention relates to a wireless local area network (WLAN) radio frequency (RF) front-end transceiver, and more particularly, to implement a wireless LAN RF front-end transceiver on a single board. The present invention relates to a wireless LAN RF front-end transceiver using a power down mode to stop a transmission function during a reception mode operation.

That is, the present invention orthogonal frequency division multiplexing (hereinafter referred to as 'OFDM') of the 5GHz band configured by modifying and developing a wireless LAN transmission and reception system implemented in a conventional 2.4GHz band and an existing mobile communication system. The present invention relates to a wireless LAN RF front-end transceiver.

1 is an exemplary view of a conventional wireless LAN RF transceiver.

As shown in FIG. 1, a transmitter of a conventional WLAN RF transceiver device, which is implemented in a 2.4 GHz band, generates an intermediate frequency (IF) signal loaded with data from the first local signal generator 140. A modulator 135 for modulating using a local signal, a first amplifier 130 for amplifying the modulated data signal, a data signal amplified by the first IF amplifier and a second local signal generator 150 And a drive amplifier 120 for amplifying and generating the power to drive the up-mixer 125 and the power amplifier 115 to combine the two signals into an RF signal by synthesizing the two signals, and the drive amplifier 120. A power amplifier 115 for amplifying and generating a signal suitable for transmission using the power amplified by the < RTI ID = 0.0 >

In addition, the receiver of the transmitting and receiving device generates a low noise amplifier 170 for amplifying the data signal received through the antenna 100, the data signal amplified by the low noise amplifier 170 and the second local signal generator 150 A down mixer 165 for inputting the local signal, synthesizing the two signals into an IF signal, a second IF amplifier 160 for amplifying the down-converted data signal in the down mixer 165, and the second And a demodulator 155 for demodulating the data signal amplified by the IF amplifier 160 using the local signal generated by the first local signal generator 140.

In addition, the transmission and reception apparatus includes a transmission and reception selection switch 110 for selecting a transmission and reception mode of the transceiver and an antenna 100 for transmitting and receiving an RF signal.

However, as described above, in the transmission and reception device implemented on one board, there is a problem in that the signal quality is degraded due to interference caused by a signal transmitted from a component of a transmitter during a reception operation.

In addition, as described above, the wireless LAN RF transceiver implemented in the conventional 2.4 GHz band is insufficient for radio space to perform various functions required by the increase in the demand for multimedia services and the rapid development of communication signal processing technology. There is a problem that there is a limit due to the limitation of the processing speed.

The present invention has been proposed to solve the above problems, and in implementing a wireless LAN RF front-end transceiver on one board, the wireless LAN RF using a power down mode to stop a transmission function during a reception mode operation. The purpose is to provide a front-end transceiver.

In other words, an object of the present invention is to provide a wireless LAN RF front-end transmission and reception apparatus suitable for the OFDM scheme of the 5GHz band configured by modifying and developing the wireless LAN transmission and reception system implemented in the conventional 2.4GHz band and the existing mobile communication system. .

1 is an exemplary view of a conventional WLAN RF transceiver device.

Figure 2 is a configuration diagram of an embodiment of a wireless LAN RF front-end transceiver according to the present invention.

Figure 3a is a detailed configuration diagram of an embodiment of the local signal generation unit used in the wireless LAN RF front-end transceiver according to the present invention.

Figure 3b is a detailed configuration diagram of an embodiment of a received signal strength detector used in a wireless LAN RF front-end transceiver according to the present invention.

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

200: antenna 230: first up-conversion unit

240: second up-converter 250: first down-converter

260: second downconversion section 270: local signal generation section

In order to achieve the above object, the present invention provides a wireless LAN RF front-end transceiver, comprising: local signal generating means for generating first and second local signals of a specific frequency band; First upconverting means for upconverting a data signal input from a baseband to an intermediate frequency signal using a first local signal generated from said local signal generating means; Second upconverting means for synthesizing the intermediate frequency signal upconverted by the first upconverting means with the second local signal generated from the local signal generating means and upconverting the RF signal into an RF signal; First downconverting means for downconverting the received RF data signal into an intermediate frequency signal synthesized with a second local signal generated from the local signal generating means; Second downconverting means for downconverting the intermediate frequency signal downconverted by the first downconverting means into a baseband signal using the first local signal generated from the local signal generating means; And a transmission / reception mode selection means for selecting a transmission / reception mode through the antenna.

In addition, the present invention further provides a power down means for preventing the interference of the received signal due to the operation of the transmitter by stopping the driving of the amplifier by suppressing the driving voltage applied to the transmitting amplifier during the receiving operation. It is characterized by including.

The standard (IEEE 802.11a) of the wireless LAN transceiver having a transmission rate of 6 to 54 Mbps, which was determined in July 1999, is shown in Table 1 below.

transmitter receiving set Parameter Requirements Parameter Requirements Frequency of use 5.15 to 5.35 GHz (8 channels) Frequency of use 5.15 to 5.35 GHz (8 channels) RF channel bandwidth 16.6 MHz RF channel bandwidth 16.6 MHz Output power 200 mW (with up to 6dBi antenna gain) Noise figure 10 dB (5 dB margin) Operating voltage 5 V Reception sensitivity -82 dBm Adjacent Channel Impact 16 dB

The present invention is to provide a 5GHz band wireless LAN RF front-end transceiver based on the RF standard of the IEEE 802.11a.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of an embodiment of a wireless LAN RF front-end transceiver according to the present invention.

As shown in FIG. 2, the 5 GHz band WLAN RF front-end transceiver according to the present invention is configured to generate first and second local signals having a predetermined bandwidth around 900 MHz and 4.35 GHz. A local signal generator 270 including local signal generators 272 and 276 and a local signal of 900 MHz band generated from the first local signal generator 272 to convert a data signal input from the baseband into an intermediate frequency signal. A first up-converter 230 and a signal up-converted by the first up-converter 230 are combined with a local signal in the 4.35 GHz band generated by the second local signal generator 276 to form an RF signal. The second up-converter 240 for converting to the second, the RF signal input from the second up-converter 240, to remove the noise signal to be suitable for transmitting using the antenna 200, the antenna 200 Received through A band pass filter 210 that receives a data signal and removes a noise signal, and outputs an output data signal of the second up-converter 240 using the band pass filter 210 and the antenna 200. Transmission or reception mode selection switch 220 for selecting whether or not to receive the data signal received by the antenna 200 through the band pass filter 210, the data input from the band pass filter 210 A signal is input from the first down-converter 250 and the first down-converter 250, which are synthesized with a local signal in the 4.35 GHz band generated by the second local signal generator 276 and converted into an intermediate frequency signal. A second downconverter for converting the intermediate frequency signal into a baseband In-phase / Quadrature-phase (I / Q) signal by using a 900 MHz band local signal generated from the first local signal generator 272. 260.

Looking at the detailed configuration and operation of each component as follows.

First, the first up-converter 230 receives an in-phase / quadature-phase (I / Q) signal input from a baseband digital-to-analog (D / A) converter and outputs a first local signal generator 272. An I / Q modulator 231 for converting the IF signal into a IF signal having a center frequency of 900 MHz using the first local signal generated by the second signal, an amplifier 232 for amplifying the IF signal, and an signal amplified by the amplifier 232. Transmit Surface Acoustic Wave (SAW) filter 233 to block noise of the signal, and a transmit attenuator 234 to attenuate the signal from the SAW filter 233.

In this case, the transmission attenuator 234 has a dynamic range of 38 dB, and if saturation occurs in the IF, the transmission attenuator 234 may adjust the degree of attenuation externally.

In addition, the second up-converter 240 mixes the signal passing through the transmission attenuator 234 with a local signal in the 4.35 GHz band generated by the second local signal generator 276 to form an RF signal in the 5.15 to 5.35 GHz band. A power amplifier 244 connected to an up-mixer 241 for forming a signal, a band-pass filter 242 for removing a noise signal of an RF signal mixed by the up-mixer 241, and the band-pass filter 242. And a power amplifier 244 for maximizing the output power of the transmitter in accordance with the power from the drive amplifier 243 to produce a power sufficient to drive.

The first down converter 250 of the transceiver includes a low noise amplifier 251 for amplifying a signal input from the antenna 200 and a gain amplifier for amplifying the RF signal amplified by the low noise amplifier 251. 252, a band pass filter 253 for removing noise from the signal amplified by the gain amplifier 252, and a second local signal generator 276 with the noise removed from the band pass filter 253. And a down mixer 254 for synthesizing and demodulating the local signal in the 4.35 GHz band.

In this case, the low noise amplifier 251 should have a noise figure of 2 dB or less in consideration of the overall noise figure of the system.

In addition, the signal output from the down mixer 254, the RF signal of the center frequency 5.15 ~ 5.35 GHz passed through the band pass filter 253 and the center frequency 4.25 ~ 4.45 generated by the second local signal generator 276 A signal having a center frequency of 900 MHz, which is a difference between a center frequency and a local signal of GHz.

In addition, the second down converter 260 of the transmitting and receiving device receives a IF signal having a center frequency of 900 MHz from the down mixer 254 and receives a SAW filter 261 and the SAW filter 261 to remove noise. An amplifier 262 for amplifying the signal from which the noise has been removed, a SAW filter 263 for removing the noise of the signal amplified by the amplifier 262, and conserving a complete spectrum of the OFDM signal, and the SAW filter 263 Demodulate the attenuated signal in the attenuator 264 using a local signal generated in the attenuator 264 and the first local signal generator 272 having a dynamic range of 38 dB to attenuate the signal from And an I / Q demodulator 265 for dividing into an in-phase (I) and quadrature-phase (Q) signal and outputting the signal to the baseband 290.

On the other hand, a part of the signal passing through the SAW filter 263 is input to the received signal strength detector 280 for detecting the strength of the signal coming into the receiver.

In order to use each module of the transceiver device as a transceiver device that operates independently using the same frequency on one board, in the present invention, as shown in FIG. 2, the isolation degree for separating transmission and reception is about 30 dB. The transmission and reception separation switch 220 is used, and a power down mode (Power Down Mode, 235, 245, 246) for blocking a signal transmitted from a component of a transmitter at the time of reception is configured to enable safe reception.

At this time, the power down mode 235, 245, 246, in the receiving operation, by suppressing the driving voltage of the transmitting amplifier (232, 243, 244) to stop the driving of the amplifier, thereby preventing the transmission to occur, thereby improving the quality of the received signal Perform the function.

3A is a detailed block diagram of an embodiment of a local signal generator used in a wireless LAN RF front-end transceiver according to the present invention.

The local signal generator 300 shown in FIG. 3A is a detailed configuration diagram of the local signal generator including only one local signal generator of the two local signal generators 272 and 276 shown in FIG. 2. A frequency divider 350 to divide the reference signal generator 310 to generate a reference signal of 20MHz, a phase comparator 320 to control the oscillator and the noise is removed by comparing the divided signal and the reference signal of 20MHz It consists of a loop filter 330 and an oscillator 340 for generating a signal.

By the operation of the above components, the second local signal generator 276 of FIG. 2 generates a signal having a center frequency of 4.25 to 4.45 GHz, which is changed by the phase comparator 274 at 20 MHz intervals. Enables transmission and reception on a desired channel, and also enables the first local signal generator 272 of FIG. 2 to obtain an accurate 900 MHz local signal without any frequency shift.

3B is a detailed block diagram of an embodiment of a received signal strength detector used in a wireless LAN RF front-end transceiver according to the present invention.

As shown in FIG. 3B, the received signal strength detector 280 is a digital signal for receiving the signal strength of the analog signal measured by the log detector 410 and the log detector 410 for measuring the strength of the received signal. An A / D converter 420 is provided for converting to. Thus, by measuring the magnitude of the received signal periodically and transmitting it to the medium access controller (MAC), it is possible to detect whether the receiving end is currently receiving operation. In other words, when a signal is received in a ready state that is normally in a ready state and a signal of a certain intensity is input and measured, the signal is transmitted to the MAC to be switched to a state of reception, or in a state of reception, when a signal of a certain intensity or more is received for a predetermined time. If it is not input continuously, switch to the standby mode.

In addition, it performs a function to prevent the saturation (saturation) of the system that occurs when the received signal strength at the receiving end is too high.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

In the present invention as described above, in implementing a wireless LAN RF front-end transceiver on one board, by using the power down mode to stop the transmission function during the reception mode operation, by reducing the occurrence of the inter-signal interference signal of the received signal This has the effect of improving quality.

In particular, the present invention transforms and evolves a wireless LAN transmission / reception system implemented in the 2.4 GHz band and an existing mobile communication system to configure a wireless LAN RF transceiver of the 5 GHz band, thereby enabling the implementation of a more compact system, and providing a comfortable radio wave. There is an effect that it is possible to obtain a space and improve the transmission speed due to the wide bandwidth.

In addition, the present invention is applied to the future bidirectional system has an effect that can support smooth communication between the access point (AP) and the terminal.

Claims (9)

In the wireless LAN RF (Frequency Radio Frequency (RF)) front-end transceiver, Local signal generating means for generating first and second local signals of a specific frequency band; First upconverting means for upconverting a data signal input from a baseband to an intermediate frequency signal using a first local signal generated from said local signal generating means; Second upconverting means for synthesizing the intermediate frequency signal upconverted by the first upconverting means with the second local signal generated from the local signal generating means and upconverting the RF signal into an RF signal; First downconverting means for downconverting the received RF data signal into an intermediate frequency signal synthesized with a second local signal generated from the local signal generating means; Second downconverting means for downconverting the intermediate frequency signal downconverted by the first downconverting means into a baseband signal using the first local signal generated from the local signal generating means; And Transmission / reception mode selection means for selecting a transmission / reception mode through the antenna WLAN RF front-end transceiver comprising a. The method of claim 1, Power down means for stopping the driving of the amplifier by suppressing the driving voltage applied to the transmitting amplifier in the receiving operation to prevent the interference to the received signal according to the operation of the transmitting stage WLAN RF front-end transceiver further comprising. The method of claim 2, Receiving signal detection means for measuring the strength at the receiving end with respect to the received signal, determining whether it is in a receiving state or a waiting state according to the measured result, and protecting the transmitting and receiving device from a signal having a strength of a predetermined intensity or more. WLAN RF front-end transceiver further comprising. The method according to any one of claims 1 to 3, The local signal generating means, For signal conversion for transmission / reception of the input data signal, a first local signal having a predetermined bandwidth around 900 MHz is generated and provided to the first up-conversion means and the second down-conversion means, and 4.35 GHz. A wireless local area network (RF) front-end transmitting and receiving device, characterized in that for generating a second local signal having a predetermined bandwidth to the second up-converting means and the first down-conversion means. The method of claim 4, wherein The first upconversion means, Converting the data signal input from the baseband into an intermediate frequency signal having a predetermined bandwidth around 900 MHz by using a first local signal having a predetermined bandwidth around 900 MHz received from the local signal generating means; WLAN RF front-end transceiver. The method of claim 5, The second upconversion means, 5.25 by combining an intermediate frequency signal having a predetermined bandwidth centered on the 900 MHz input from the first up-conversion unit and the second local signal having a predetermined bandwidth centered on the 4.35 GHz received from the local signal generating unit. A wireless LAN RF front-end transceiver, characterized in that for converting to a RF signal having a predetermined bandwidth around the GHz. The method of claim 6, The first down conversion means, RF data signal having a predetermined bandwidth centered at 5.25 GHz received from the antenna and the second local signal having a predetermined bandwidth centered at 4.35 GHz received from the local signal generating unit are synthesized, and then centered at 900 MHz. Wireless RF front-end transceiver, characterized in that for converting to an intermediate frequency signal having a bandwidth of. The method of claim 7, wherein The second downconverting means, Baseband an intermediate frequency signal having a predetermined bandwidth centered on the 900 MHz received from the first downconverting means by using a first local signal centered on the 900 MHz received from the local signal generator; Wireless RF front-end transceiver device characterized in that the conversion to the signal. The method of claim 8, The second downconverting means, In converting the intermediate frequency signal into a baseband signal, through the multi-stage filtering, the converted baseband signal is a signal suitable for Orthogonal Frequency Division Multiplexing (OFDM). WLAN RF frontend transceiver.