KR20090109768A - RF Transceiver for Femto Cell Station and the Femto Cell Station - Google Patents

Abstract

PURPOSE: A wireless transmission circuit of a femto cell base station is provided to use an existing mobile terminal signal receiving path as a base station signal receiving path through which a macro base station transmits a signal. CONSTITUTION: A wireless transmission circuit(200) of a femto cell base station includes a wireless transmitter(250), a wireless receiver(270), a duplexer(291), a switch(293), the first BPF(295), a modem unit(210), and a conversion unit(230). The wireless transmitter outputs the first wireless signal to be transmitted to a mobile communication terminal. The wireless receiver coverts one of the second wireless signal received from the terminal and the third wireless signal received from a macro base station into a baseband signal. The duplexer connects the wireless transmitter and receiver with one antenna(297). The switch is prepared between the duplexer, antenna and wireless receiver.

Description

Wireless transceiver for femtocell base station and its femtocell base station {RF Transceiver for Femto Cell Station and the Femto Cell Station}

The present invention relates to a wireless transmission / reception circuit of a femtocell base station, and integrates a mobile station signal reception path and a base station signal reception path transmitted by a macro base station into one. The present invention relates to a wireless transmission / reception circuit of a femtocell base station and a femtocell base station.

Femto Cell (Femto Cell) is a small base station that provides a Wideband Code Division Multiple Access (WCDMA) mobile communication service for an area of about 200m radius, also known as Home Node-B (Home Node-B). Compensation for the quality of mobile communication services by being installed in areas where shadows of macro cells are deteriorated or shadowed areas, such as homes or buildings, or in in-building environments where subscribers are densely populated, resulting in insufficient base station channel capacity. It is installed for the purpose of doing so. In particular, the femtocell uses a general-purpose Internet line for communication with the core network, the core control station of the mobile communication network, so that installation cost and maintenance cost are low, and since the femtocell can be installed anywhere in the Internet line, There is an advantage.

A femtocell base station for a wideband code-division multiple access (WCDMA) based femtocell transmits and receives a radio signal from a mobile station (UE). The conventional radio transmission / reception circuit of a femtocell base station has a transceiver structure in which a base station transmission / reception path is separately configured according to a frequency division duplex (FDD) scheme, and a femtocell signal transmission path for transmitting a radio signal to a mobile station (UE). These include a Cell Signal Transmitter Path and a UE Signal Receiver Path for receiving a radio signal transmitted from a mobile terminal (UE).

However, a femtocell base station must also receive a radio signal transmitted from a neighboring macro base station (Node-B) for a sniffer function, and for this purpose, a base station signal receiving path (Node-B signal receiver) for receiving a macro base station signal Path must be provided. The femtocell base station synchronizes based on the information received from the macro base station and uses its cell information to recognize the femtocell coverage.

An object of the present invention is a wireless transceiver circuit of a femtocell base station capable of receiving a mobile terminal signal reception path (UE Signal Receiver Path) and a base station signal reception path (Node-B Signal Receiver Path) transmitted by the macro base station as one; In providing a femtocell base station.

In order to achieve the above object, a wireless transmission / reception circuit of a femtocell base station comprises: a wireless transmitter for outputting a first wireless signal to be transmitted to a mobile communication terminal; A wireless receiver converting one of the second wireless signal received from the terminal and the third wireless signal received from the macro base station into a baseband signal; A duplexer for connecting the wireless transmitter and the wireless receiver to one antenna; A switch provided between the duplexer, the antenna, and a wireless receiver, the switch connecting the antenna and the wireless receiver to receive the third wireless signal under control of the controller; A first band pass filter (BPF) provided between the switch and a wireless receiver to filter the third wireless signal; A modem unit for modulating data input to the wireless transmitter according to a WCDMA scheme and demodulating data output from the wireless receiver; And a converting unit converting the digital output of the modem unit into an analog signal and providing the converted signal to the wireless transmitting unit and converting the analog output of the wireless receiving unit into a digital signal and providing the converted digital signal to the modem unit.

The wireless receiver may include an impedance matching unit matching an impedance with respect to a second wireless signal received from the duplexer and a third wireless signal received from the first BPF; A low noise amplifier for low noise amplifying the signal output from the impedance matching unit; A receiver-BPF for bandpass filtering the output of the low noise amplifier; A variable local oscillator for outputting an oscillation signal having an oscillation frequency for converting the second radio signal or the third radio signal into a baseband signal; And a receiver-mixer for converting the second wireless signal and the third wireless signal into a baseband signal using the oscillation signal.

According to an embodiment, the switch is controlled by an external controller, and the antenna is connected to the first BPF according to a switching control signal of the controller which is output after being initialized with power on. The antenna may be connected to the duplexer after the synchronization with the downlink of the macro base station performed by the modem unit is completed based on the information included in the radio signal.

According to another embodiment of the present invention, a femtocell base station operating a femtocell and providing a mobile communication service to a mobile communication terminal includes a wireless transmission and reception circuit and a controller.

The wireless transmission / reception circuit outputs a first radio signal to the terminal for receiving the mobile communication service, receives a second radio signal from the terminal, and receives a third radio signal from the macro base station to synchronize downlink to the terminal. .

The control unit controls the wireless transmission / reception circuit to receive the third wireless signal.

The wireless transmission / reception circuit of a femtocell base station according to the present invention reduces the size of a femtocell base station by using an existing mobile terminal signal reception path (UE signal receiver path) as a base station signal reception path (Node-B signal receiver path) transmitted by a macro base station. Enables low cost design.

In addition, the femtocell base station according to the present invention can more easily monitor the transmission signal of the macro cell, by analyzing the base station information of the macro cell (Macro Cell), synchronization acquisition and automatic cell planning which is the original purpose of the sniffer mode (Auto Cell Planning) can be performed, and the power control can be made easier based on the Received Signal Strength Indication (RSSI) of the macro cell.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a diagram illustrating a femtocell of a femtocell base station having a wireless transceiver circuit of the present invention. Referring to FIG. 1, a femtocell base station 110 having a wireless transmission / reception circuit 200 is connected to a mobile communication terminal (hereinafter, simply referred to as a “terminal”) 130 and is also connected to a macro base station (Node-B) 150. Connected.

The wireless transmit / receive circuit 200 uses a transceiver structure in which a base station transmit / receive path is separately configured according to a frequency division duplex (FDD) scheme of a wideband code division multiple access (WCDMA) protocol. A frequency from 1920 MHz to 1980 MHz is used for data reception from the terminal 130, and a frequency from 2110 MHz to 2170 MHz is used for data transmission to the terminal 130.

In addition, the wireless transceiver 200 must also receive a radio signal transmitted from the neighboring macro base station 150 for the sniffer (Sniffer) function of the femtocell base station 110, the terminal signal using one radio receiver for this purpose A UE and a Node-B Signal Receiver Path may be formed. The femtocell base station 110 adapts its downlink channel synchronization to the downlink channel of the macro base station 150 based on the information received through the base station signal reception path, and grasps its cell information to cover the femtocell coverage. Used to recognize Coverage.

The control unit 300 generally controls the transmission and reception of the radio signal of the radio transmission and reception circuit 200, and basically allows one radio receiver included in the radio transmission and reception circuit 200 to form a terminal signal reception path. Only the corresponding radio receiver forms a base station signal reception path.

Hereinafter, a radio signal of a first frequency band (for example, 2140 MHz) transmitted from the femtocell base station 110 to the terminal 130 is referred to as a 'first radio signal', and the terminal 130 is connected to the femtocell base station 110. A radio signal of a second frequency band (for example, 1950 MHz) to transmit is referred to as a 'second radio signal'. In addition, a radio signal of a first frequency band (for example, 2140 MHz) received from the macro base station 150 is referred to as a 'third radio signal'.

2 is a wireless transceiver circuit diagram of a femtocell base station according to an embodiment of the present invention. Referring to FIG. 2, the wireless transceiver circuit 200 includes a modem unit 210, a converter 230, a wireless transmitter 250, a wireless receiver 270, a duplexer 291, a switch ( 293, a first band pass filter (BPF) 295, and an antenna 297. The wireless transmission / reception circuit 200 is connected to a predetermined control unit 300 and transmits and receives a wireless signal according to a control signal output from the control unit 300.

The modem unit 210 is connected to a digital to analog converter (DAC) 231 and an analog to digital converter (ADC) 233 included in the converter 230. The modem unit 210 provides the DAC 231 by spreading, mixing, and modulating the transmission channel to be transmitted to the terminal 130 based on the WCDMA protocol and from the ADC 233 of the conversion unit 230. Demodulate the digital signal. The modem unit 210 analyzes macro base station information using a signal received from the macro base station 150 among signals provided from the ADC 233 to perform synchronization acquisition and auto cell planning. Check the RSSI (Received Signal Strength Indication) of the cell and use it for power control.

The DAC 231 of the conversion unit 230 converts the digital signal provided from the modem unit 210 into an analog signal and provides it to the wireless transmitter 250, and the ADC 233 is an analog provided from the wireless receiver 270. The signal is converted into a digital signal and provided to the modem unit 210. The data transmitted from the modem unit 210 to the wireless transmitter 250 (or the wireless receiver 270) via the converter 230 is separated into an I stream and a Q stream. However, the mixing and separation of the I stream and the Q stream, etc. are obvious to those of ordinary skill in the art and do not correspond to the technical features of the present invention, and thus will not be described separately.

The rest of the configuration of the wireless transmission / reception circuit 200 will be described based on the flow of the wireless signal. First, the first wireless signal through the femto-cell signal transmitter path will be described.

Various channels are used for the downlink from the femtocell base station 110 to the terminal 130, and a pilot channel, a synchronization channel, a broadcasting channel, a channel for paging, and the like correspond to the first wireless signal. The first wireless signal provided from the modem unit 210 and the conversion unit 230 and transmitted to the terminal 130 passes through the wireless transmitter 250 → duplexer 291 → switch 293 → antenna 297.

The radio transmitter 250 may be a radio transmitter circuit that may be included in an RF transceiver of a physical layer of a base station Node-B of a mobile communication network. The included configuration of the wireless transmitter 250 of FIG. 2 is an example, and includes a transmitter configured to modulate a signal transmitted from the DAC 231 using the transmitter local oscillator 251 and the transmitter local oscillator 251. A mixer 253, a power amplifier 257 for amplifying the output of the transmitter-BPF 255 and the transmitter-BPF 255 for bandpass filtering the output signal of the transmitter-mixer 253 are provided. Include. In addition, the wireless transmitter 250 may further include a coupler for checking a wireless signal or an isolator for fixing a signal output to the antenna 297 and protecting the power amplifier 257.

The signal output from the wireless transmitter 250 is transmitted to the switch 293 through the duplexer 291. The duplexer 291 is a filter and separates the radio transmitter 250 and the radio receiver 270 connected to one antenna 297. Accordingly, the duplexer 291 allows the radio transmitter 250 and the radio receiver 270 to use one antenna 297 using different frequencies. The signal transmitted to the switch 293 is transmitted to the terminal 130 via the antenna 297. The function of the switch 293 is described again below.

The second wireless signal received from the terminal 130 is input to the antenna 297 → switch 293 → duplexer 291 → wireless receiving unit 270 is converted into a baseband analog signal, and then converted to 230 Is passed to. In addition, the third wireless signal received from the macro base station 150 is input to the antenna 297 → switch 293 → first BPF 295 → radio receiver 270. The first BPF 295 provided between the switch 293 and the wireless receiver 270 receives a third wireless signal that does not pass through the duplexer 291 by filtering the signal of the first frequency band.

The wireless receiver 270 includes a low noise amplifier (LNA) 273 for amplifying a signal passing through the impedance matching unit 271, the impedance matching unit 271 with a minimum of noise, a receiver-BPF 275, And a receiver-mixer 277 and a variable local oscillator 279, and may receive a second wireless signal and a third wireless signal. In addition, the wireless receiver 270 further includes an image reject filter provided at a front end or a rear end of the receiver-mixer 277 to remove an image frequency component amplified by the low noise amplifier 273. can do.

The impedance matching unit 271 includes an impedance matching circuit for the second wireless signal and the third wireless signal in consideration of the transmission characteristics due to the impedance which varies according to the frequency, and individually matches the second wireless signal and the third wireless signal. Thus, the second radio signal and the third radio signal are received without attenuation.

The radio signal passing through the impedance matching unit 271 passes through the low noise amplifier 273 and the receiver-BPF 275. The low noise amplifier 273 and the receiver-BPF 275 should have uniform wireless characteristics by making the entire first frequency band and the second frequency band in-band.

The signal passing through the receiver-BPF 275 is input to the receiver-mixer 277, and the receiver-mixer 277 receives the signal passed through the receiver-BPF 275 from the signal input from the variable local oscillator 279. Multiply it to a Zero-Intermediate Frequency (Zero IF) signal.

The variable local oscillator 279 oscillates a signal provided to the receiver-mixer 277 in response to the second wireless signal of the second frequency and the third wireless signal of the first frequency according to the oscillation control signal of the controller 300. The frequency can be varied.

As such, whether the wireless receiver 270 processes the second wireless signal or the third wireless signal is determined by the variable local oscillator 279 and the receiver-mixer 277 controlled by the oscillation control signal. Whether the second wireless signal or the third wireless signal is input to the wireless receiver 270 is determined by the switch 293.

The switch 293 basically connects the antenna 297 and the duplexer 291, thereby enabling transmission and reception of the first wireless signal and the second wireless signal between the duplexer 291 and the antenna 297. However, the switch 293 connects the antenna 297 and the first BPF 295 according to the switching control signal output from the control unit 300, so that the duplexer 291 receives the third radio signal transmitted by the macro base station 150. It provides to the wireless receiving unit 270 without passing through and blocks the connection with the terminal 130. The switch 293 is preferably a single pole 2 throw (SP2T) digital switch. As described above, the third wireless signal is filtered by placing the first BPF 295 between the switch 293 and the wireless receiver 270 in place of the duplexer 291.

Hereinafter, a method of receiving a third wireless signal, which is a macro base station signal, will be described based on the operation of the controller 300 with reference to FIG. 3. 3 is a flowchart provided to explain a method for receiving a macro base station signal according to an embodiment of the present invention.

When the femtocell base station 110 is powered on and initialized (S301), the controller 300 outputs a switching control signal to cause the switch 293 to connect the antenna 297 and the first BPF 295. The third wireless signal may be received (S303).

The control unit 300 outputs the oscillation control signal so that the radio receiver 270 receives the third radio signal so that the variable local oscillator 279 converts the third radio signal into a baseband signal (S305). Subsequently, the controller 300 determines whether the modem unit 210 synchronizes its downlink channel to the downlink channel of the macro base station 150 based on the digital data provided by the converter 230. (S307).

As a result of the determination in step S307, if the downlink channel of the femtocell base station 110 is synchronized with the downlink channel of the macro base station 150, the switch 293 to connect the antenna 297 and the duplexer 291 to the first The radio signal and the second radio signal are transmitted and received (S309).

In the above-described method, the femtocell base station 110 may receive the macro base station 150 signal and the radio signal of the terminal 130 by using one radio receiver 270.

In addition, in the embodiment of FIG. 3, the control unit 300 controls the wireless transceiver circuit 200 to receive the third radio signal only after the power is turned on, and in the normal state, the wireless transceiver circuit 200 is connected to the terminal ( 130) to send and receive. However, according to another exemplary embodiment, the wireless transceiver 200 may receive the third wireless signal when necessary.

The invention can be implemented in methods, devices and systems. In addition, when the present invention is implemented in computer software, the components of the present invention may be replaced with code segments necessary for performing necessary operations. The program or code segment may be stored in a medium that can be processed by a microprocessor and transmitted as computer data coupled with carrier waves via a transmission medium or communication network.

The media that can be processed by the microprocessor include electronic circuits, semiconductor memory devices, ROMs, flash memory, electrically erasable programmable read-only memory (EEPROM), floppy disks, optical disks, and hard disks. (Hard) Includes the ability to transmit and store information such as disks, fiber optics, wireless networks, and the like. Computer data also includes data that can be transmitted over electrical network channels, optical fibers, electromagnetic fields, wireless networks, and the like.

In addition, although the preferred embodiment of the present invention has been shown and described above, the present invention is not limited to the above-described specific embodiment, the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

1 is a diagram illustrating a femtocell of a femtocell base station having a wireless transceiver circuit of the present invention;

2 is a wireless transmission and reception circuit diagram of a femtocell base station according to an embodiment of the present invention, and

3 is a flowchart provided to explain a method for receiving a macro base station signal according to an embodiment of the present invention.

Claims (6)

A wireless transmitter for outputting a first wireless signal to be transmitted to a mobile communication terminal; A wireless receiver converting one of the second wireless signal received from the terminal and the third wireless signal received from the macro base station into a baseband signal; A duplexer for connecting the wireless transmitter and the wireless receiver to one antenna; A switch provided between the duplexer, the antenna, and a wireless receiver, the switch connecting the antenna and the wireless receiver to receive the third wireless signal under control of the controller; A first band pass filter (BPF) provided between the switch and a wireless receiver to filter the third wireless signal; A modem unit for modulating data input to the wireless transmitter according to a WCDMA scheme and demodulating data output from the wireless receiver; And And a conversion unit converting the digital output of the modem unit into an analog signal and providing the converted signal to the wireless transmission unit, and converting the analog output of the modem unit into a digital signal and providing the digital signal to the modem unit. The method of claim 1, The wireless receiver, An impedance matching unit matching an impedance with respect to a second wireless signal received from the duplexer and a third wireless signal received from the first BPF; A low noise amplifier for low noise amplifying the signal output from the impedance matching unit; A receiver-BPF for bandpass filtering the output of the low noise amplifier; A variable local oscillator for outputting an oscillation signal having an oscillation frequency for converting the second radio signal or the third radio signal into a baseband signal; And And a receiver-mixer (Mixer) for converting the second radio signal and the third radio signal into a baseband signal by using the oscillation signal. The method of claim 1, The switch is controlled by an external control unit, and is connected to the antenna and the first BPF according to a switching control signal of the control unit which is output after being initialized with power on and included in the third wireless signal. And the antenna is connected to the duplexer after the synchronization with the down link of the macro base station performed by the modem unit is completed based on the received information. A femtocell base station operating a femtocell and providing a mobile communication service to a mobile communication terminal, A wireless transmission / reception circuit for outputting a first radio signal to the terminal for receiving the mobile communication service, receiving a second radio signal from the terminal, and receiving a third radio signal from the macro base station to synchronize downlink to the terminal; And And a control unit for controlling the wireless transmission / reception circuit to receive the third wireless signal. The method of claim 4, wherein The wireless transmission and reception circuit, A wireless transmitter for outputting the first wireless signal; A wireless receiver converting one of the second wireless signal and the third wireless signal into a baseband signal; A duplexer provided between the wireless transmitter, the wireless receiver, and an antenna to separate the first and second wireless signals transmitted and received through the antenna; A switch provided between the duplexer, the antenna, and a wireless receiver, for directly connecting the antenna and the wireless receiver to receive the third wireless signal under control of the controller; A first band pass filter (BPF) provided between the switch and a wireless receiver to filter the third wireless signal; A modem unit for modulating data input to the wireless transmitter according to a WCDMA scheme and demodulating data output from the wireless receiver; And And a converting unit converting the digital output of the modem unit into an analog signal and providing the converted signal to the wireless transmitting unit and converting the analog output of the modem unit into a digital signal and providing the converted digital signal to the modem unit. The method of claim 5, The wireless receiver, An impedance matching unit matching an impedance with respect to a second wireless signal received from the duplexer and a third wireless signal received from the first BPF; A low noise amplifier for low noise amplifying the signal output from the impedance matching unit; A receiver-BPF for bandpass filtering the output of the low noise amplifier; A variable local oscillator for outputting an oscillation signal having an oscillation frequency for converting the second radio signal or the third radio signal into a baseband signal under the control of the controller; And And a receiver-mixer (Mixer) for converting the second radio signal and the third radio signal into a baseband signal by using the oscillation signal.

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