KR100489899B1 - Wireless transmitting and receiving device in subscriber terminal device of wireless subscriber network system - Google Patents

Abstract

The present invention relates to a radio transceiver in a RIU of a WLL system for enabling a radio transceiver in an RIU for radio matching with a base station, and comprising a transmission signal for radio transmission and reception with a base station. And an antenna duplexer which separates the received signal and transmits the signal according to each path, a wireless receiver converting the RF signal of the base station transmitted through the antenna duplexer into an IF signal, and a subscriber side transmitted through the D / A converter. A radio transmitter converts an IF signal into an RF signal and transmits the signal to the base station through an antenna duplexer, and converts the RF signal into an IF signal in the radio receiver and demodulates the IF signal or modulates the IF signal in the radio transmitter. Local signal generator for generating each local signal for converting the IF signal into RF signal , By reducing mutual interference in high frequency bands at least 2GHz processing transmitted and received RF signal has the effect that enables subscribers to get easily provide wireless telephone service from the telephone company.

Description

Wireless transceiver in subscriber station of wireless subscriber network system

The present invention relates to a radio interface unit (hereinafter referred to as "RIU") of a wireless local loop (WLL) system, and to wirelessly transmit and receive within a RIU for wireless matching with a base station. The present invention relates to a radio transceiver in a RIU of a WLL system capable of realizing a unit.

In general, the WLL system is a system that forms a link using a wireless system instead of a wired line from a telephone station to a subscriber terminal. It is expected to play an important role in building information infrastructure in the future.

The WLL system is largely composed of a RIU for constructing a radio link with a base station, a base station for making a radio link with the RIU, and a base station controller and a telephone exchange for controlling the base station.

As illustrated in FIG. 1, the RIU converts a radio frequency (RF) signal received from a base station (not shown) into an intermediate frequency (IF) signal and then converts the digital data into digital data or converts digital data input from a subscriber. The RF unit 1 converts the converted IF signal into an RF signal after converting it into an analog signal, and decodes the digital data converted by the RF unit 1 or encodes the input digital data. Code division multiple access (CDMA) modem unit 2 outputted to RF unit 1 and digital data decoded by CDMA modem unit 2 to a corresponding time slot, or A time switch 3 for switching digital data to a corresponding time slot and outputting the same to the CDMA modem unit 2, and the 32 Kbps data switched and input from the time switch 3 are 64 Kbps Pulse Code Mo. demodulated data, or modulates the input 64 Kbps PCM data into 32 Kbps data and outputs the vocoder 4 to the time switch 3 and the 64 Kbps PCM data demodulated by the vocoder 4 as an analog signal. Or a combo unit 5 for converting the input analog signal into 64 Kbps PCM data and outputting the same to the vocoder 4, and the analog signal converted by the combo unit 5 is impedance-matched. A slick unit 6 for outputting to the telephone of the subscriber or an analog signal input from the telephone of the subscriber, and outputting the impedance signal to the combo unit 5, and the CPU 7 for controlling the operation of the respective building blocks. It is composed of

Meanwhile, in order to implement a RIU configured as described above in a commercially available WLL system, an RF signal having a frequency band of 2.3 to 2.4 GHz is transmitted and received to the RF unit 1 for wireless matching with a radio access unit of a base station. It needs to be implemented to provide a radio interface between the base station and the RIU.

The present invention has been made in view of the above, and an object thereof is to implement a wireless transceiver for wireless matching with a base station in a RIU of a WLL system so that subscribers can easily receive wireless telephone service from a telephone station. The present invention provides a radio transceiver in a RIU.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation of the radio transceiver in the RIU of the WLL system according to the present invention.

FIG. 2 is a block diagram of a wireless transceiver in a RIU of a WLL system according to the present invention. An antenna duplexer which separates a transmission signal and a reception signal for wireless transmission / reception with a base station and transmits the signals according to respective paths ( 10), the wireless receiver 20 converting the RF signal of the base station side transmitted through the reception path of the antenna duplexer 10 into an IF signal, and the IF of the subscriber side transmitted through the D / A converter. After converting the signal into an RF signal, the radio transmitter 40 for transmitting to the base station through the transmission path of the antenna duplexer 10, and the radio receiver 20 converts the RF signal into an IF signal and demodulates the IF signal. Or a local oscillator 50 for generating a local signal for modulating the IF signal in the wireless transmitter 40 and converting the modulated IF signal into an RF signal.

The wireless receiver 20 is a low noise amplifier (hereinafter referred to as "LNA") for low-noise amplifying the RF signal received through the receiving path of the antenna duplexer 10 and the LNA (21) RF SAW (Surface Acoustic Wave) filter 22 to block the unnecessary band of the low noise amplified RF signal and pass only the signal of the desired band, and the RF signal passed through the RF SAW filter 22 A down mixer 23 for mixing with a 2455 MHz local signal supplied through the splitter 54 of the local signal generator 50 and converting it into an IF signal of 70 MHz, and converting the down mixer 23. An IF SAW filter 24 for blocking an unnecessary band signal among the IF signals and an AGC (Automatic Gain Control) amplifier (AMP) 25 for a predetermined level amplification of the magnitude of the IF signal passing through the IF SAW filter 24. And the IF signal amplified by the AGC amplifier 25 from a main line to a sub line. A coupler (Coupler) 26 for fling, and an IF amplifier 27 for a predetermined level amplification of the IF signal amplified by the AGC amplifier 25 transmitted through the coupler 26 to a size required by a demodulator; The IF signal amplified by the IF amplifier 27 is supplied with a local signal of 140 MHz from the splitter 56 of the local signal generator 50 as quadrature I (In-phase) and Q (Quadrature) data. A demodulator (28) for demodulating, a data buffer (29) for matching the demodulated I, Q data with the output impedance to an A / D converter, and a coupler ( The RSSI detector 30 which measures the intensity of the IF signal amplified by the AGC amplifier 25 flowing through the circuit 26 and converts it to a DC level, and the DC voltage detected by the RSSI detector 30 and the CPU in the RIU. The amplification level of the AGC amplifier 25 is controlled in accordance with the gain control signal of (7), and the gain of the transmission signal is adjusted. It consists of the AGC controller 31 for outputting the Tx gain control signal for control.

The wireless transmitter 40 includes a data buffer 41 for receiving I and Q data of orthogonal components input through a D / A converter by input impedance matching, and a splitter 56 of the local signal generator 50. A modulator 42 for receiving a local signal of 140 MHz and modulating I, Q data of orthogonal components input through the data buffer 41 into an IF signal of 70 MHz, and an IF modulated by the modulator 42 IF SAW filter 43 for blocking an unnecessary band of signals and passing only a signal of a desired band, and the magnitude of the IF signal passing through the IF SAW filter 43 according to the power control information and the reception level transmitted from the base station. VGA IF amplifier 44 for a predetermined level amplification, and IF signal amplified by VGA IF amplifier 44 mixed with a local signal of 2455 MHz supplied through splitter 54 of the local signal generator 50 to 2315 MHz An up mixer 45 for converting to an RF signal of RF SAW filter 46 to block the unnecessary band signal generated during the conversion process of the up mixer 45, a preamp (Pre AMP), a drive amplifier (Drive AMP), and a final amplifier (Final AMP) A Tx amplifier 47 for sequentially amplifying the RF signal passing through the RF SAW filter 46 to the antenna duplexer 10, a gain control signal of the CPU 7 in the RIU, and the wireless receiver 20 The AGC control unit 48 controls the amplification level of the VGA IF amplifier 44 in accordance with the Tx gain control signal of the AGC control unit 31.

The local signal generation unit 50 generates a local signal according to the VCTCXO 51 generating a reference voltage according to the control signal output from the CDMA modem unit 2 in the RIU, and the reference voltage output from the VCTCXO 51. Local signals of 2455 MHz and 140 MHz for providing to the wireless receiving unit 20 and the wireless transmitting unit 40 according to the PLL unit 52 generating a reference voltage for the PLL unit 52 and the reference voltage output from the PLL unit 52. The generated RF VCO unit 53 and the IF VCO unit 54, and the 2455 MHz local signal output from the RF VCO unit 53, the down mixer 23 and the wireless transmitter 40 of the wireless receiver 20. A splitter 54 for outputting to the up mixer 45 of the control unit, and a 140 MHz local signal output from the IF VCO unit 55 to the demodulator 28 and the wireless transmitter 40 of the wireless receiver 20. And splitters 56 respectively output to the modulator 42 of.

Referring to the operation of the radio transceiver in the RIU of the WLL system according to the present invention configured as described above are as follows.

First, a process of receiving an RF signal transmitted from a base station in a RIU will be described. The RF signal transmitted from the base station is received through a reception path of the antenna duplexer 10, and the received RF signal is transmitted to the wireless receiver 20. Output

Accordingly, the LNA 21 in the wireless receiver 20 low noise amplifies the RF signal received through the reception path of the antenna duplexer 10. In this case, the LNA 21 almost completely influences the noise index of the receiver. It should be amplified low noise, and in order to prevent the signal from being buried under the white noise by the attenuation element of the rear stage, sufficient amplification in consideration of the intermodulation characteristics.

Subsequently, the RF SAW filter 22 having a sudden out-of-band attenuation characteristic blocks the unnecessary band signal from the low noise amplified RF signal in the LNA 21 and passes only the desired band signal, followed by the down mixer 23. The RF signal passed through the RF SAW filter 22 is mixed with a local signal of 2455 MHz supplied through the splitter 54 of the local signal generator 50 to be converted into an 70 MHz IF signal.

Then, the IF SAW filter 24 having excellent cut off characteristics blocks the unnecessary band signal generated during the conversion of the down mixer 23, and the IF SAW through the AGC amplifier 25. The magnitude of the IF signal passing through the filter 24 is amplified by a predetermined level.

That is, since the magnitude of the RF signal received by the antenna of the antenna duplexer 10 is severely changed due to the distance transmitted from the base station, the path difference, etc., the AGC amplifier 25 constantly demodulates a signal having a large level deviation. To do this, the output level of the IF signal needs to be amplified constantly regardless of the change in the input.

At this time, the AGC amplifier 25 amplifies the magnitude of the IF signal according to the control signal of the AGC control unit 31, the AGC control unit 31 is amplified in the AGC amplifier 25 introduced by the coupler 26. The amplification level of the AGC amplifier 25 is controlled according to the DC voltage of the RSSI detector 30 which measures the intensity of the IF signal and converts it to the DC level and the gain control signal of the CPU 7 in the RIU.

In addition, the AGC control unit 31 transmits a Tx gain control signal for controlling the gain of the transmission signal according to the DC voltage detected by the RSSI detector 30 and the gain control signal of the CPU 7 in the RIU. ) Is output to the AGC control unit 48.

Subsequently, if the IF signal of the AGC amplifier 25 amplified to a predetermined level under the control of the AGC control unit 31 is output to the IF amplifier 27 through the coupler 26, the IF amplifier 27 is a demodulator ( Amplify again to the required level in 28).

Subsequently, the demodulator 28 receives a 140 MHz local signal from the splitter 56 of the local signal generator 50 and demodulates the IF signal amplified by the IF amplifier 27 into I, Q data of orthogonal components. Finally, I, Q data of the quadrature component demodulated by the demodulator 28 is converted to match the output impedance through the data buffer 29 and then output to the A / D converter.

Next, a process of transmitting an RF signal from a subscriber to a base station will be described. An I / Q data of quadrature components inputted through a D / A converter in a RIU is received by impedance matching in the data buffer 41, and then modulator 42 is received. ) Receives a 140 MHz local signal from the splitter 56 of the local signal generator 50 and modulates the I, Q data of the quadrature component input through the data buffer 41 into an IF signal of 70 MHz.

Subsequently, in order to satisfy spurious characteristics, the IF SAW filter 43 having excellent cut-off characteristics cuts out unnecessary band signals among the IF signals modulated by the modulator 42, and the VGA IF amplifier 44 is turned off. Through the IF SAW filter 43, the amplitude of the IF signal passed through the predetermined level is amplified.

In this case, the VGA IF amplifier 44 amplifies the magnitude of the IF signal according to the control signal of the AGC control unit 48. The AGC control unit 48 controls the gain control signal of the CPU 7 in the RIU and the wireless signal. The amplification level of the VGA IF amplifier 44 is controlled according to the Tx gain control signal of the AGC controller 31 in the receiver 20.

That is, the VGA IF amplifier 44 changes the transmission output according to the power control information and the reception level transmitted from the base station for power control in the reverse link.

Subsequently, the up mixer 45 mixes the IF signal amplified by the VGA IF amplifier 44 with the 2245 MHz local signal supplied through the splitter 54 of the local signal generator 50 to produce a 2315 MHz RF signal. The RF SAW filter 46 then attenuates the unnecessary band signal generated during the conversion of the up mixer 45 and passes only the desired band signal.

Thereafter, the RF signal passing through the RF SAW filter 46 is sequentially amplified while sequentially passing through the preamplifier, the drive amplifier, and the final amplifier of the Tx amplifier 47.

The final RF signal amplified as described above is radiated to the outside through the antenna of the antenna duplexer 10 and transmitted to the base station.

On the other hand, the local signal generator 50 generates a local signal of 2455MHz and 140MHz through the general PLL circuit configuration to provide to the wireless receiver 20 and the wireless transmitter 40.

In addition, the antenna duplexer 10 should reduce the insertion loss (Insertion Loss) of the receiving side in order to improve the noise figure of the receiving side, and also the insertion loss of the transmitting side in order to reduce the output loss, and transmit The isolation must be large to prevent the signal from being induced to the receiver.

As described above, the present invention implements one receiving path and a single conversion method and one transmitting path and a single conversion method to reduce the number of internal local signals and improve the situation of mutual interference. Doing.

As described above, the wireless transceiver of the present invention has an effect that subscribers can easily receive wireless telephone service from a telephone station by reducing mutual interference and transmitting and receiving RF signals even in a high frequency band of 2GHz or more.

1 is a block diagram of a subscriber station of a general wireless subscriber network system;

2 is a block diagram of a wireless transceiver in a subscriber station of a wireless subscriber network system according to the present invention;

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

10: antenna duplexer 20: wireless receiver

21: LNA 22,46: RF SAW Filter

23: Down mixer 24,43: IF SAW filter

25: AGC Amplifier 26: Coupler

27: IF amplifier 28: demodulator

29,41: data buffer 30: RSSI detector

31,48: AGC control unit 40: wireless transmission unit

42: modulator 44: VGA IF amplifier

45: up mixer 47: Tx amplifier

50: local signal generator 51: VCTCXO

52: PLL section 53: RF VCO section

54, 56: splitter 55: IF VCO section

Claims (2)

In a WLL system composed of a RIU, a base station, a base station controller, and a telephone station, and forms a link using a wireless system instead of a wired line from a telephone station to a subscriber station, An antenna duplexer (10) for transmitting and receiving a transmission signal and a reception signal for wireless transmission and reception to and from the base station by wireless transmission and reception in the RIU for wireless access to the base station and the antenna duplexer (10) of the The wireless receiver 20 converts the RF signal of the base station side transmitted through the reception path into an IF signal, and converts the IF signal of the subscriber side transmitted through the D / A converter into an RF signal and then the antenna duplexer 10. A radio transmitter 40 for transmitting to the base station through the transmission path of the radio receiver, and the RF receiver 20 converts the RF signal into an IF signal and demodulates the IF signal or modulates the IF signal in the radio transmitter 40. A local signal generator 50 for generating a local signal for converting the modulated IF signal into an RF signal, The wireless receiver, LNA 21 for low-noise amplifying the RF signal received through the receiving path of the antenna duplexer 10, and cuts out the unnecessary band of the low-noise amplified RF signal in the LNA 21 and passes only the signal of the desired band A down mixer for mixing the RF signal passing through the RF SAW filter 22 and the RF SAW filter 22 with the local signal supplied through the splitter 54 of the local signal generator 50 to convert to an IF signal. (23), an IF SAW filter 24 for blocking unnecessary band signals among the IF signals converted by the down mixer 23, and a predetermined level amplification of the magnitude of the IF signal passing through the IF SAW filter 24; In the AGC amplifier 25, the coupler 26 coupling the IF signal amplified by the AGC amplifier 25 from a main line to a sub line, and the AGC amplifier 25 transmitted through the coupler 26. IF amplifier amplifies the amplified IF signal to a level required by the demodulator And a demodulator 28 for receiving a local signal from the splitter 56 of the local signal generator 50 and demodulating the IF signal amplified by the IF amplifier 27 into I, Q data of quadrature components. And a data buffer 29 for outputting the demodulated I, Q data demodulated by the demodulator 28 to an A / D converter, and the AGC amplifier 25 introduced through the coupler 26. The AGC amplifier 30 measures the strength of the amplified IF signal and converts it to a DC level, and the AGC amplifier according to the DC voltage detected by the RSSI detector 30 and the gain control signal of the CPU 7 in the RIU. AGC control part 31 which controls the amplification level of 25) and outputs the Tx gain control signal for controlling the gain of a transmission signal. Wireless transceiver in the subscriber station of the wireless subscriber network system comprising a. The wireless transmitter 40 of claim 1, wherein the wireless transmitter 40 includes a data buffer 41 for receiving I and Q data of orthogonal components inputted through a D / A converter by input impedance matching, and the local signal generator 50. A modulator (42) for receiving a local signal from a splitter (56) of the modulator (42) and modulating the I, Q data of the orthogonal component inputted through the data buffer (41) into an IF signal; IF SAW filter 43 which cuts out the unnecessary band signal and passes only the desired band signal, and the magnitude of the IF signal passing through the IF SAW filter 43 is constant according to the power control information transmitted from the base station and the reception level. VGA IF amplifier 44 for level amplification and the IF signal amplified by the VGA IF amplifier 44 are mixed with the local signal supplied through the splitter 54 of the local signal generator 50 to convert to an RF signal. Up mixer 45 and the conversion process of the up mixer 45 And an RF SAW filter 46 for blocking an unnecessary band signal generated from the signal, and a preamplifier, a drive amplifier, and a final amplifier, sequentially amplifying the RF signal passing through the RF SAW filter 46 to perform the antenna duplexer ( 10) the VGA IF amplifier 44 according to the Tx amplifying unit 47 to be transmitted, the gain control signal of the CPU 7 in the RIU, and the Tx gain control signal of the AGC control unit 31 in the wireless receiver 20. And a AGC control unit (48) for controlling the amplification level of the subscriber station.