KR100990908B1 - FA Selection Type RF Repeater and Repeating Method thereof - Google Patents

Abstract

A frequency selective wireless repeater and a wireless relay method thereof are disclosed. The wireless repeater of the present invention can search for FA (Frequency Assignment) according to the mobile communication protocol serviced in the installation area, and selectively amplify and relay only the main FA in the corresponding area. To this end, the wireless repeater detects the signal-to-noise ratio (Ec / lo) for the radio signal received for each base station for each FA, and selects the main FA of the region based on the detected signal-to-noise ratio. The radio repeater relays only the radio signals of the detected primary FA.

Wireless Repeater, Frequency Selective, Frequency Assignment, Ec / lo

Description

Frequency selective wireless repeater and wireless repeating method thereof {FA Selection Type RF Repeater and Repeating Method

The present invention relates to a frequency selective wireless repeater for searching for FA (Frequency Assignment) serviced in a corresponding area according to a predetermined mobile communication protocol, and selectively amplifying and relaying only the main FA in the corresponding area, and a wireless relay method thereof. .

Wireless communication protocols known to date are allocated a predetermined frequency band, and divided into a plurality of frequency assignment frequency (FA) frequencies and used as multiple channels. For example, the frequency band of the 3rd generation mobile communication network (IMT-2000) is 1920 to 1980 MHz upward and 2110 to 2170 MHz downward, and each of 12 FA frequencies is divided into 5 MHz.

Meanwhile, signal transmission from a base station belonging to a wireless mobile communication network system to a mobile terminal is limited due to various obstacles in air space. The device used to overcome this limitation is a wireless repeater.

The wireless repeater is used to solve the shadow area that does not receive a good communication service by amplifying and retransmitting a weak signal transmitted from at least one base station to the service area. Since the repeaters installed in the shadow area do not know what FA frequencies are used in the area, they amplify and transmit the entire frequency band serviced by the service provider.

However, only certain FA frequencies can be serviced in a particular cell. For example, a base station of a typical macro cell or a pico cell may divide sectors and allocate different FA frequencies to each sector in order to have an optimal system capacity for a corresponding channel environment. Therefore, the terminal located in the cell to which the 3 FA frequency is assigned recognizes only the 3 FA frequency and sets the call to only the 3 FA frequency. However, conventional wireless repeaters installed in this cell must amplify all FA frequencies in the service band, including the 3 FA frequencies.

This method is amplified to a frequency band that is not being serviced in the region, affecting the reception sensitivity of the terminal or the base station, causing a decrease in the call quality.

On the other hand, the wireless repeater may receive signals from a plurality of adjacent base stations. Each base station uses a scrambling code or a PN offset to distinguish the base stations, and may use a plurality of FA frequencies (eg, three) for the downlink to the terminal.

SUMMARY OF THE INVENTION An object of the present invention is to provide a frequency selective wireless repeater and a method for wirelessly repeating a relay by selectively amplifying only main FAs in a corresponding area by searching for a FA (Frequency Assignment) serviced in a corresponding area according to a predetermined mobile communication protocol. Is in.

In order to achieve the above object, a wireless repeater according to the present invention includes: a first antenna for receiving a plurality of FA (Frequency Assignment) radio signals used for a downlink of a plurality of base stations; A down-converter for converting the radio signal into a baseband signal and then converting the radio signal into a digital signal; Obtaining a signal-to-noise ratio for each of the plurality of FAs based on the digital signal converted by the down-converter unit, detecting a first rank FA having a maximum signal-to-noise ratio among the plurality of FAs, and converting the A frequency adjusting unit outputting a signal of a first rank FA; An up-converter for converting the signal output from the frequency adjusting unit into an analog wireless signal and outputting the converted signal; And a second antenna for transmitting the radio signal converted by the up-converter to the terminal.

According to an embodiment, if the second rank FA whose difference between the signal-to-noise ratio of the first rank FA among the plurality of FAs is equal to or less than a reference value is detected, any one of the first rank FA and the second rank FA is detected. The signal of the selected FA can be output.

The frequency adjusting unit may include a plurality of interface units corresponding to each of the plurality of FAs, and filtering, phase equalizing, and interpolating the corresponding FA signals from the digital signals converted by the down converter unit; A switching unit connecting one of the output signals of the plurality of interface units to the up-converter unit; An energy measuring unit configured to receive output signals of the plurality of interface units and measure a signal-to-noise ratio for each FA; And an FA detector configured to detect the selected FA based on the measurement result of the energy measuring unit and to control the switching unit to connect an interface unit to output the signal of the selected FA to the up-converter unit.

In addition, the frequency adjusting unit is provided between the switching unit and the up-converter unit, each of which is connected to one of the plurality of interface units through the switching unit, and filters the same band as the filtering band of the connected interface unit. The apparatus may further include a plurality of FA filters configured to output negatively. In this case, the switching unit switches the connection between the plurality of interface units and the plurality of FA filter units, and connects the interface unit corresponding to the signal of the selected FA and the FA filter unit under the control of the FA detection unit.

In addition, the signal-to-noise ratio of each of the plurality of FAs is obtained by calculating the ratio of signal power (Ec) to noise power (lo) for the pilot channel (Pilot Channel) for each base station received through each FA. The maximum value of the noise power can be determined by the signal-to-noise ratio of the corresponding FA.

In the frequency selective relay method of a wireless repeater according to another embodiment of the present invention, receiving a plurality of FA (Frequency Assignment) radio signals used for the downlink (Dawn Link) of a plurality of base stations to convert to a baseband signal Converting to a digital signal; Obtaining a signal-to-noise ratio for each of the plurality of FAs based on the converted digital signal and detecting a first rank FA having a maximum signal-to-noise ratio among the plurality of FAs; Filtering a signal of the first rank FA of the digital signals; And converting the filtered first priority FA signal into an analog radio signal and transmitting the same to the terminal.

According to an embodiment of the present disclosure, the relay method may further include detecting a second rank FA of the plurality of FAs whose difference from the signal-to-noise ratio of the first rank FA is less than or equal to a reference value; And when the second rank FA is detected, filtering the signal of the selected one of the first rank FA and the second rank FA from the baseband signal, converting the signal to an analog radio signal, and transmitting the same to the terminal. have.

The wireless repeater according to the present invention can selectively amplify and relay a main FA being serviced in a corresponding area. Accordingly, the signal of the frequency band that is not being serviced in the corresponding area but is received and amplified may affect the reception sensitivity of the terminal or the base station and degrade the call quality.

If the FA in service is found in the proposed macro cell where the repeater is located, only the optimal FA can be transmitted because there is no need to service the entire band to the local terminal. This feature enables low cost production, low power and miniaturization of wireless repeaters, and can facilitate network design based on miniaturization and low power.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the drawings.

1 is a block diagram of a frequency selective wireless repeater according to an embodiment of the present invention. The wireless repeater of the present invention may be provided in an area where radio signals of at least one base station are received according to Code Division Multiplex Access (CDMA), CDMA2000 1xRTT, or Wideband CDMA (WCDMA) protocols to relay radio signals between the base station and the mobile terminal. have. The wireless repeater 100 may be used for uplink from a terminal to a base station as well as a downlink from a base station to a terminal. The following description mainly focuses on the example used for the downlink.

According to an embodiment, the repeater may be designed to relay a radio signal in both directions using the wireless repeater 100 of FIG. 1.

The wireless repeater 100 detects a wireless FA (Frequency Assignment) frequency currently in use from a radio signal between the base station and the terminal to filter, amplify, and relay only the detected FA frequency. Through this, the wireless repeater 100 does not need to amplify all downlink FA frequencies of a plurality of base stations serving the corresponding region so that the local region is serviced.

Referring to FIG. 1, the wireless repeater 100 includes a first antenna 101, a down-converter 103, a second antenna 105, an up-converter 107, and the like. And a frequency adjusting unit 109. In addition, the wireless repeater 100 may be applied to a plurality of FAs assigned to a plurality of base stations, and the wireless repeater 100 of FIG. 1 assumes that four FA radio signals are received for convenience of description. Assume it is designed to handle four FAs.

The down converter unit 103 receives a radio signal of a downlink (or forward channel) of at least one base station through the first antenna 101 and uses a local oscillator (LO) to transmit a baseband (LO). After converting to a Zero Intermediate Frequency) signal, it is converted into a digital signal and provided to the frequency adjusting unit 109.

The down converter unit 103 includes an impedance matching unit connected to the first antenna 101, a low noise amplifier (LNA) for minimizing amplification of a signal passing through the impedance matching unit, and a band pass filter connected to the low noise amplifier (BPF: Band Pass Filter), a mixer for converting to a baseband signal, a local oscillator (LO), and an analog-to-digital converter.

The up-converter 107 converts the digital baseband signal provided from the frequency adjuster 109 into an analog signal, and then uses a local oscillation signal having the same frequency as the local oscillation frequency of the down-converter 103. The conversion is performed through the second antenna 105. The baseband signal output from the frequency adjusting unit 109 is filtered to include only the signal of the FA frequency detected by a predetermined algorithm, and the signal transmitted to the main service FA of the area where the wireless repeater 100 is installed is Corresponding.

The up-converter 107 is a digital-to-analog converter (DAC), a local oscillator (LO), a mixer (Mixer) for converting the baseband signal to a wireless signal, and band-pass filtering the output signal of the mixer It may include a band pass filter (BPF) and a power amplifier (Amp) for amplifying the output of the band pass filter.

The down converter unit 103 and the up converter unit 107 can be any conventional wireless reception or transmission circuit included in the physical layer of the terminal and base station of the mobile communication network.

The frequency adjusting unit 109 analyzes the baseband digital signal input from the down converter unit 103 to detect a main FA frequency being serviced in the area where the wireless repeater 100 is installed, and inputs the down converter unit 103. Only the detected FA frequency components of the baseband signals to be filtered are output to the up-converter 107. To this end, the frequency adjusting unit 109 includes the first to Nth interface units 111 to 117, the switching unit 131, the first to Nth FA filter units 151 to 157, the energy measuring unit 171, and the FA. The detector 173 is included. Here, N represents the number of FAs allocated to the plurality of base stations, and since it is assumed that four FAs are used above, N becomes 4 in the following description.

Each of the first to fourth interface units 111 to 117 includes a digital filter, a digital phase equalizer, and a digital interpolation filter, and each of the digital signals input from the down converter unit 103. After filtering by FA band, phase equalization and interpolation are performed. In other words, the first interface unit 111 is a first FA frequency component, the second interface unit 113 is a second FA frequency component, the third interface unit 115 is a third FA frequency component and a fourth interface unit ( 117 filters and processes the fourth FA frequency component. To this end, the filters included in each of the first to fourth interface units 111 to 117 filter the corresponding FA band.

The switching unit 131 switches between the first to fourth interface units 111 to 117 and the first to fourth FA filter units 151 to 157, respectively. The baseband signal output from the down converter unit 103 is input to the first to fourth interface units 111 to 117 and then to the first to fourth FA filter units 151 to 157 through the switching unit 131. Delivered. In this process, the switching unit 131 connects only the interface unit corresponding to the main FA detected by the FA detection unit 173 and the FA filter unit. For example, if 2 FA is the detected main FA, the switching unit 131 is controlled to connect only the second interface unit 113 and the second FA filter unit 153 by the FA detection unit 173.

The first to fourth FA filter units 151 to 157 are for improving the filtering performance of the frequency adjusting unit 109. Each of the first to fourth FA filter units 151 to 157 filters a signal of a corresponding FA frequency band. To the up-converter 107. However, since the FA filters are already included in the first to fourth interface units 111 to 117, the first to fourth FA filter units 151 to 157 may not be an essential configuration. In this case, the switching unit 131 may directly connect one of the first to fourth interface units 111 to 117 to the up-converter unit 107.

The energy measuring unit 171 is connected to the first to fourth interface units 111 to 117 and represents a signal-to-noise ratio Ec / lo which is a numerical value representing a ratio of signal power Ec to noise power lo for each FA signal. ) Is measured and provided to the FA detection unit 173. Ec / lo refers to the ratio of pilot energy missing during one PN chip period to the total power spectral density in the receive band, which represents the overall receive sensitivity and is usually expressed in dB.

The measurement of Ec / lo is performed by obtaining signal power (Ec) versus noise power (lo) for a pilot channel for each base station identification code for each FA, as shown in Equation 1 below.

Here, Ec (Pilot) is the average energy per PN chip (Energy) for the pilot channel, RSSI (Radio Signal Strength Indicator) represents the received electric field strength.

When a plurality of adjacent base stations use the same FA, the wireless repeater 100 may receive a signal from different base stations for one FA band. Therefore, the signal-to-noise ratio is calculated by FA and each FA is classified by base station identification code. In the WCDMA standard, the base station classification code is a primary scrambling code, and in 1xRTT of CDMA 2000, the base station identification code is a short pseudo random noise code (PN code).

The FA detector 173 detects the main FA of the region based on the result provided from the energy measuring unit 171. FIG. 2 is a flowchart provided for explaining the method for detecting the main FA, and the operation of the FA detection unit 173 will be described with reference to FIG. 2.

When the energy measuring unit 171 measures Ec / lo for each base station for each FA and provides the FA detection unit 173 (S201), the FA detection unit 173 detects a maximum Ec / lo value for each FA to determine the FA. Determined by Ec / lo. For example, when the first FA signal includes pilot channels of three base stations, Ec / lo is obtained for each of the three base stations, and the maximum value of the obtained three Ec / lo is determined as the Ec / lo of the corresponding FA (S203). ).

The FA detection unit 173 detects an FA having a maximum Ec / lo among all FAs (for example, four FAs) (hereinafter referred to as 'first-order FA') based on the FA-specific Ec / lo determined in step S203 ( S205).

The FA detection unit 173 compares the Ec / Io of the first FA with the Ec / Io of the other FA to detect an FA having an Ec / lo similar to the first FA (hereinafter referred to as a “second rank FA”). In other words, the FA detection unit 173 detects, as the second FA, FAs whose difference from the Ec / lo of the first FA among the remaining FAs is equal to or less than the reference value. The method for obtaining the second rank FA may be expressed by Equation 2 below.

Here, Ec / lo (primary FA) is the Ec / lo of the primary FA, and Ec / lo (Nth FA) is the Ec / lo of the FA excluding the first FA among all N FAs. The FA that is not the first rank FA that satisfies Equation 2 will be the second rank FA (S207).

The FA detection unit 173 may basically select the first FA as the main FA of the region, or select one FA from the first FA and the second FA as the main FA of the region. The FA detection unit 173 controls the switching unit 131 to connect only the corresponding FA according to the selection result. If there is no second rank FA, the FA detection unit 173 determines the first rank FA as the main FA (S209).

Under the control of the FA detector 173, the switching unit 131 switches only the main FA. For example, when 3FA is selected as the main FA, the switching unit 131 connects only the third interface unit 115 and the third FA filter unit 155 under the control of the FA detection unit 173. Accordingly, only three FAs are provided to the up-converter unit 107 to be converted into a wireless signal and transmitted, and other FA signals are blocked and cannot be converted to a wireless signal.

Frequency adjustment of the wireless repeater 100 of the present invention is performed by the above method.

According to another exemplary embodiment, the FA detection unit 173 may control the switching unit 131 to output both the first and second rank FAs instead of one selected from the first and second rank FAs. In other words, the wireless repeater 100 removes only the FA band signal having a signal-to-noise ratio below a predetermined reference level, and relays all of the FA bands having a signal-to-noise ratio above a reference level.

As described above, the wireless repeater 100 of the present invention may be included in the wireless repeater, and FIG. 3 shows an example thereof.

3 is a block diagram of a two-way wireless repeater having a wireless repeater of FIG. 1, which corresponds to a frequency selective wireless repeater for selecting and relaying a frequency. The wireless repeater 300 may control overall transmission / reception of downlink and uplink radio signals between the base station and the terminal by a separate controller (not shown).

Referring to FIG. 3, the wireless repeater 300 may include a first antenna 101, a first down converter unit 103, a second antenna 105, a first up converter unit 107, and a first frequency adjusting unit 109. ), A first duplexer 301, a second duplexer 303, a second down converter 305, a second up-converter 307, and a second frequency adjuster 309. The wireless repeater 300 includes the wireless repeater 100 of FIG. 1 as it is.

 The first down converter section 103, the first frequency adjusting section 109 and the first up converter section 107 relay the downlink signal from the base station to the terminal, and the second down converter section 305 and the second frequency. The adjusting unit 309 and the second up-converter unit 307 relay the uplink signal from the terminal to the base station.

The first and second duplexers 301 and 303 are filters and separate down converters 103 and 305 and up converters 107 and 307 connected to one antenna 101 or 105. Accordingly, the duplexers 301 and 303 allow the down converter units 103 and 305 and the up converter units 107 and 307 to use one antenna 101 and 105.

As a result, the wireless repeater 300 may selectively relay only the downlink and uplink signals through the main FA of the region.

According to an embodiment, the first frequency adjusting unit 109 and the second frequency adjusting unit 309 may be controlled by a common energy measuring unit (eg, identification number 171) and FA detection unit (eg, identification number 173). . In other words, the energy measuring unit is included in only one of the first frequency adjusting unit 109 and the second frequency adjusting unit 309, and the common FA detecting unit is respectively provided to the first frequency adjusting unit 109 and the second frequency adjusting unit 309. The included switching unit can be controlled.

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 block diagram of a frequency selective wireless repeater according to an embodiment of the present invention;

2 is a flow chart provided in the description of a method for detecting a primary FA, and

3 is a block diagram of a two-way wireless repeater with the wireless repeater of FIG. 1.

Claims (8)

A first antenna for receiving radio signals of a plurality of frequency assignments used for downlinks of a plurality of base stations; A down-converter for converting the radio signal into a baseband signal and then converting the radio signal into a digital signal; Obtain a signal-to-noise ratio for each of the plurality of FAs based on the digital signal converted by the down-converter, detect a first-rank FA having the largest signal-to-noise ratio among the plurality of FAs, and output the signal of the first-rank FA However, when a second rank FA is detected in which the difference between the signal-to-noise ratio of the first rank FA is less than or equal to a reference value among the plurality of FAs, outputting a signal of the selected FA among the first rank FA and the second rank FA is frequency. Adjusting unit; An up-converter for converting the signal output from the frequency adjusting unit into an analog wireless signal and outputting the converted signal; And A second antenna for transmitting the wireless signal converted by the up-converter to a terminal; The frequency adjusting unit, For each of the plurality of FAs, a ratio of signal power (Ec) to noise power (lo) of pilot channels (Pilot Channel) for each base station received through each FA is obtained, and the signal power to noise power obtained for each base station is obtained. Wireless repeater, characterized in that the maximum value of the ratio to determine the signal-to-noise ratio of the FA. delete The method of claim 1, The frequency adjusting unit, A plurality of interface units corresponding to each of the plurality of FAs, for outputting the filtered, phase-equalized and interpolated FA signals from the digital signals converted by the down-converter; A switching unit connecting one of the output signals of the plurality of interface units to the up-converter unit; An energy measuring unit configured to receive output signals of the plurality of interface units and measure a signal-to-noise ratio for each FA; And And a FA detector configured to detect the selected FA based on a measurement result of the energy measuring unit and to control the switching unit to connect an interface unit outputting a signal of the selected FA to the up-converter unit. The method of claim 3, The frequency adjusting unit, A plurality of FA filter units provided between the switching unit and the up-converter unit, each of which is connected to one of the plurality of interface units through the switching unit, and filters the same band as the filtering band of the connected interface unit to output to the up-converter unit Including, The switching unit switches the connection between the plurality of interface unit and the plurality of FA filter unit, the wireless repeater, characterized in that for connecting the interface unit and the FA filter unit corresponding to the signal of the selected FA under the control of the FA detection unit . delete Receiving a plurality of FA (Frequency Assignment) radio signals used for a downlink of a plurality of base stations, converting the radio signals into baseband signals, and then converting them into digital signals; Obtaining a signal-to-noise ratio for each of the plurality of FAs based on the converted digital signal and detecting a first rank FA having a maximum signal-to-noise ratio among the plurality of FAs; Detecting a second rank FA of the plurality of FAs whose difference from the signal-to-noise ratio of the first rank FA is equal to or less than a reference value; And The signal of the first rank FA among the digital signals is filtered and then converted into an analog radio signal and transmitted to the terminal. When the second rank FA is detected, the signal of the selected FA among the first rank FA and the second rank FA is detected. Filtering the signal from the baseband signal, converting the signal into an analog radio signal, and transmitting the same to the terminal; The signal-to-noise ratio is a ratio of signal power (Ec) to noise power (lo) for a pilot channel for each base station received through each FA, and the ratio of the signal power to noise power obtained for each base station. Frequency selective relay method of a wireless repeater, characterized in that the maximum value. delete delete

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