JP4611842B2 - Repeater device - Google Patents

Description

The present invention relates to a repeater device that reduces power consumption during transmission from an information terminal to a base station.

  In data communication between an information terminal (hereinafter referred to as “mobile terminal” as an example) and a base station, an OFDM (Orthogonal Frequency Division Multiplexing) communication method has been conventionally used in data communication between a mobile terminal and a base station. It is a communication system that is environmentally friendly and capable of realizing high-speed data transmission with relatively simple signal processing.

  In addition, the OFDM communication scheme is promising as a communication scheme for downlink data transmission from a base station to a mobile terminal.

  On the other hand, when applied to uplink data transmission from a mobile terminal to a base station, the OFDM signal has the disadvantages that the amplitude fluctuation of the time waveform is large and the peak / average / power ratio is large, resulting in poor radio wave propagation conditions. In a difficult communication environment, that is, an environment with a high attenuation or an environment with a large signal distortion, there is a concern that a burden is increased on a mobile terminal with a large restriction on power consumption.

  Further, in the next-generation cellular system, there is a demand for realizing a transmission rate that is 100 times the transmission rate obtained in the current system without reducing the cell radius, and the transmission power must be increased.

  That is, it is necessary to meet the demand for realizing high-speed transmission in the uplink (uplink) even in a communication environment with poor radio wave propagation conditions while suppressing power consumption during transmission of the mobile terminal.

  The use of a repeater device that relays signals between a mobile terminal and a base station is effective as a method for solving the above-described problems.

  Hereinafter, an outline of a wireless communication system incorporating a conventional repeater device and an operation of the repeater device will be briefly described.

  Fig.9 (a) is a figure which shows the outline | summary of the uplink transmission in the radio | wireless communications system incorporating the conventional repeater apparatus.

  FIG. 9B is a diagram showing a transmission / reception band used in a conventional repeater apparatus.

  As shown in FIG. 9A, when transmitting the uplink data, the portable terminal 801 transmits to the repeater apparatus 802 using the transmission path 804, and the received repeater apparatus 802 uses the transmission path 805. Then, it transmits to the base station 803.

  Also, as shown in FIG. 9B, the mobile terminal 801 transmits an uplink signal to the repeater device 802 using the entire frequency band of the uplink transmission bandwidth 800.

  Then, repeater apparatus 802 uses the entire frequency band as it is, and similarly amplifies the received signal and transmits an uplink signal to base station 803.

As described above, the distance between the portable terminal 801 and the repeater device 802 is shortened by introducing the repeater device 802 that functions as a relay that amplifies the transmission signal from the portable terminal 801 and transmits it to the base station 803. Therefore, power consumption during transmission of the mobile terminal 801 can be suppressed.
Maeyama et al., “Development of Repeater Device for CDMA with Interference Suppression Function”, IEICE Technical Report SST2001-110

  However, in the FDD (Frequency Division Duplex) cellular system, as shown in FIG. 9B, the repeater device 802 needs to perform transmission and reception at the same time using the same frequency. There is a problem that the operation becomes unstable due to sneaking around to the input side.

  Moreover, in order to solve the wraparound on the input side of the output signal, there is a method of separating the signal by using a strong directional antenna or the like, but there is a technical difficulty in taking a fundamental countermeasure. .

  Furthermore, the above-described Non-Patent Document 1 discloses a technique for solving the above-described problem. However, in the technique disclosed in this Non-Patent Document, complicated techniques for removing interference between transmitted and received signals are disclosed. Mechanism is necessary.

Therefore, the present invention has been proposed in view of the above problems, and does not require a complicated configuration, prevents interference between transmission and reception signals, and reduces power consumption during transmission of a mobile terminal there is provided a repeater apparatus and the like for the uplink using the signal.

  In order to achieve the above object, the present invention adopts the following configuration and has the following features.

  A repeater apparatus according to the present invention is a repeater apparatus used when performing uplink transmission from an information terminal to a base station, and is unnecessary for an OFDM signal having a predetermined bandwidth transmitted from the information terminal. By combining the OFDM signal receiving unit having a bandpass filter for removing noise components and interference signal components and shifting the OFDM signal having the predetermined bandwidth to a plurality of different frequency regions, the bandwidth is wider than the input signal. An OFDM frequency conversion unit that generates an OFDM signal and a control unit that sets parameters necessary for the relay operation and controls the entire apparatus are provided.

  The repeater apparatus according to the present invention further includes a downlink receiving unit that receives control information from the base station, and extracts and stores parameters such as the predetermined bandwidth and the plurality of frequency regions from the control information. And a control information recording unit, wherein the control unit sets the parameters in the OFDM signal receiving unit and the OFDM frequency conversion unit, and follows a control information instruction from the base station.

  The repeater apparatus according to the present invention further includes a control information recording unit that records the parameters necessary for relay operation with respect to the information terminal designated in advance, and the control unit stores the parameters at the start of operation. It is set in the OFDM signal receiving unit and the OFDM frequency converting unit to perform a relay operation on the transmission signal of the information terminal specified in advance.

  Further, in the repeater apparatus according to the present invention, the frequency region received by the OFDM signal receiving unit is the lowest of the predetermined uplink bandwidths determined by the wireless communication system and equally divided by a predetermined number. The plurality of frequency regions shifted by the OFDM frequency converter are frequency regions from the second to the highest in order.

  The repeater device according to the present invention provides a frequency gap between the first uplink frequency band and the second uplink frequency band so that the frequency band on the reception side and the frequency band on the transmission side do not overlap. It is characterized by that.

  Further, in the repeater device according to the present invention, the OFDM signal receiving unit and the OFDM frequency converting unit include discrete components using FFT and IFFT instead of a configuration in which the received OFDM signal is handled as it is. An equalizer is provided that corrects distortion in a wireless transmission path after extracting each subcarrier component from the received OFDM signal by the FFT.

  As described above, according to the uplink repeater apparatus of the present invention, the first uplink frequency that is the frequency on the input side of the repeater apparatus and the second uplink frequency that is the frequency on the output side are determined by the system. By making them different from each other within a predetermined uplink bandwidth, it is possible to prevent interference between transmitted and received signals and improve stability without performing complicated processing. Thereby, the transmission power of a portable terminal can be reduced and the power consumption of a portable terminal can be reduced. Furthermore, by making the bandwidth of the second uplink frequency wider than the bandwidth of the first uplink frequency, it is possible to improve transmission quality due to the diversity effect even in an environment where radio wave propagation conditions are not good.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of a communication system and a repeater device used for the communication system according to the invention will be described in detail with reference to the accompanying drawings.

<Description of First Embodiment>
FIG. 1 is a conceptual diagram showing an outline of an operation using an uplink repeater apparatus in the wireless communication system according to the first embodiment of the present invention.

  2 to 4 show the repeater device according to the first embodiment of the present invention. In the drawings, the same reference numerals denote the same parts.

  First, the concept of the wireless communication system according to the present invention will be described below with reference to FIG.

  As shown in FIG. 1, in this wireless communication system, for example, the portable terminal 104 is in a public facility 102 such as a building, and the radio wave propagation conditions are poor with respect to the external base station 101. When it is difficult to transmit high-speed traffic data on the uplink with power, high-speed transmission of traffic data from the mobile terminal 104 to the base station 101 can be performed via the repeater device 103 in the facility. In addition, the power consumption during transmission of the mobile terminal 104 can be kept low.

  First, the mobile terminal 104 transmits an access request with the base station 101 to the base station 101 via the transmission path 105 using a low-speed control channel signal. Upon receiving the access request, the base station 101 determines from the overall propagation loss and traffic volume. If there is no problem, the base station 101 selects an appropriate repeater device 103 in the vicinity, and selects the appropriate repeater device 103 for the downlink. A relay request to the mobile terminal 104 is transmitted using the transmission path 108. The base station 101 transmits access permission to the mobile terminal 104 using the transmission path 106.

  The mobile terminal 104 that has received the access permission from the base station 101 receives the control information from the base station 101 and extracts parameters such as the first uplink frequency used for transmission from the mobile terminal 104 to the repeater device 103. The traffic data is uplinked using the first uplink frequency.

  Also, the repeater apparatus 103 that has received the relay request receives the control information from the base station 101, and uses the first uplink frequency used for transmission from the mobile terminal 104 to the repeater apparatus 103 and the repeater apparatus 103 to the base station 101. A parameter such as a second uplink frequency used for transmission to the base station 101 is extracted and set, and the uplink relay from the mobile terminal 104 to the base station 101 is performed.

  In this way, an uplink transmission route of the mobile terminal 104, the repeater apparatus 103, and the base station 101 is established, and traffic data of the mobile terminal 104 can be transmitted to the base station via the transmission path 109 and the transmission path 107. it can.

  The above procedure will be described later in the detailed operation flow of the repeater apparatus.

Here, in the transmission from the portable terminal 104 to the repeater apparatus 103, the portable terminal 104 equally divides a predetermined uplink bandwidth W defined in the wireless communication system (see, for example, FIG. 3) (for example, Data transmission is performed using an OFDM signal using one of the divided frequency regions, the lowest frequency region having a center frequency of fc and a bandwidth of W / 5 (f ₀ ).

Then, in the signal transmission from the repeater apparatus 103 to the base station 101, the repeater apparatus 103 uses the shift frequencies f _{1 to} f ₄ to each of the remaining four frequencies within the predetermined uplink bandwidth W. The frequency is shifted to a region (the entire bandwidth is 4/5 × W), the OFDM signals having the four frequency bands separated by the bandwidth f ₀ are generated, and the generated four OFDM signals are combined. Amplify and transmit data to the base station 101.

  Thereby, the mobile terminal 104 can transmit high-speed traffic data to the repeater apparatus 103 with a small transmission power, convert the signal into a signal having a large transmission power and fading resistance by the repeater apparatus, and transmit the signal to the base station 101. .

  Further, in the system using this repeater device, as described above, the frequency band on the input side of the repeater is not used for the transmission band of the mobile terminal without using the entire predetermined frequency band determined by the system as in the prior art. By making the frequency domain on the transmission side different, interference between transmitted and received signals is prevented, and the transmission bandwidth of the mobile terminal 104 is narrowed to a level that ensures an allowable communication speed, thereby reducing power consumption during transmission. ing. Furthermore, by making the transmission bandwidth of the repeater device 103 wider than the transmission bandwidth of the mobile terminal 104, it is possible to increase the resistance to fading in the wireless transmission path between the repeater device 103 and the base station 101.

  In the present embodiment, a predetermined uplink bandwidth determined in the wireless communication system is transmitted from the mobile terminal 104 to the repeater apparatus 103 as a first uplink frequency and from the repeater apparatus 103 to the base station 101. Divided into the second uplink frequency used in the above, but not all of the predetermined uplink bandwidth is necessarily allocated to the first uplink frequency and the second uplink frequency for the mobile terminal, Another part of the bandwidth can be simultaneously allocated to other information terminals for use.

  Next, the configuration and operation of the repeater apparatus 103 of the present embodiment will be described.

  FIG. 2 is a block diagram of the repeater apparatus 103 of the present embodiment.

  FIG. 3 is a diagram showing the relationship between the frequency bandwidth on the input side and the frequency bandwidth on the output side used in the repeater device of the present embodiment.

  According to FIG. 2, the repeater apparatus 103 of the present embodiment has a receiving antenna 200 that receives a transmission wave from the mobile terminal 104 and a predetermined uplink bandwidth W whose bandwidth is determined by the wireless communication system. The divided bandwidth (as described above, W divided into five, that is, W / 5), the OFDM signal receiving unit 202 including a bandpass filter whose center frequency is fc, and the remaining 4W / 5 bandwidth An OFDM frequency converter 203 that shifts and combines the OFDM signal into a plurality of different frequency regions; an uplink transmitter 205 that amplifies and transmits the converted OFDM signal; and the amplified signal as a radio wave. A transmitting / receiving antenna 201 for transmitting and receiving signals from the base station, a downlink receiving unit 208 for receiving control signals from the base station, A control information recording unit 206 that extracts and stores control information from the control signal, and a parameter such as the first uplink frequency and the second uplink frequency recorded in the control information recording unit 206 is the OFDM signal receiving unit 202 and the OFDM frequency conversion unit 203 and a control unit 207 that controls the entire repeater apparatus.

  Next, operations of the OFDM signal receiving unit 202 and the OFDM frequency converting unit 203 will be described with reference to FIGS.

As shown in FIG. 3, at the input side of the OFDM signal receiving unit 202, the mobile terminal 104 receives a reception bandwidth that is 1/5 of a predetermined uplink bandwidth W determined in the wireless communication system as described above. An OFDM signal generated using f ₀ is input. The OFDM signal receiving unit 202 passes the input OFDM signal once through a band-pass filter having a reception bandwidth f ₀ and a center frequency fc, and removes extra frequency components other than this bandwidth.

Further, the OFDM frequency converter 203 has an OFDM signal (bandwidth f ₀ ) having a center frequency fc obtained by passing through the bandpass filter and center frequencies f ₁ , f ₂ , f ₃ , and f ₄ . By multiplying by the carrier, the reception-side reception center frequency fc is frequency-shifted to f ₁ + fc, f ₂ + fc, f ₃ + fc, and f ₄ + fc, respectively. These frequency-shifted OFDM signals included in the four bandwidths are synthesized by the synthesizer 204 to generate a frequency-converted OFDM signal.

In this way, the OFDM signal having the reception bandwidth f ₀ on the input side is synthesized by being divided into four frequency regions each having a frequency separated by f ₀ , and thus has high frequency diversity characteristics and frequency selective fading. The signal is strong against.

Further, as shown in FIG. 3, by adjusting the center frequency f ₄ between the input reception band f ₀ and the transmission band of f ₄ which is the lowest center frequency (shift frequency), the frequency gap Gf is reduced. It is also possible to facilitate frequency separation between transmission and reception.

  Thus, as described above, the OFDM signal transmitted from the repeater device 103 becomes a signal that is strong against frequency selective fading, and is changed from the signal input to the repeater device to the input frequency and input from the output side. It is possible to eliminate instability due to interference on the side. The mobile terminal 104 can transmit high-speed traffic data on the uplink with low power consumption.

  Next, a configuration example replacing the OFDM signal receiving unit 202 and the OFDM frequency converting unit 203 of the repeater apparatus 103 configured to shift the OFDM signal directly according to the carrier frequency shown in FIG. 2 will be described with reference to FIG.

  FIG. 4A is a block diagram replacing the OFDM signal receiving unit 202, and FIG. 4B is a block diagram replacing the OFDM frequency converting unit 203.

  4A and 4B are substantially the same as the configuration of a receiver and a transmitter that transmit and receive ordinary OFDM signals, and this configuration is the same as that of the OFDM signal receiving unit 202 and the OFDM frequency conversion of the repeater apparatus of this embodiment. This is applied to the unit 203.

  Hereinafter, operations of the OFDM signal receiving unit 202a and the OFDM frequency converting unit 203a will be briefly described.

  In the OFDM signal receiving unit 202a that has received the OFDM signal from the mobile terminal 104, the OFDM symbol, that is, the FFT processing unit is cut out by the “Remove GI” block 401 under the control of the timing detector 400, and the cut out OFDM symbol. Is converted from serial data to parallel data by the S / P converter 402, and then subjected to FFT processing by a fast Fourier transform unit (hereinafter referred to as "FFT (Fast Fourier Transform)") 403 so that each subcarrier component is Extracted. Each extracted subcarrier component is corrected for frequency distortion caused by propagation in the transmission path by the equalizer 404, and is input to the OFDM frequency converter 203a.

  In the OFDM frequency conversion unit 203a, after being stored in the buffer 405 corresponding to each subcarrier component, inverse FFT is performed by an inverse fast Fourier transform unit (IFFT (Inverse Fast Fourier Transform)) 406, and a parallel / serial conversion unit ( (Parallel / Serial) 407 is converted into a time signal sequence. Furthermore, a guard interval GI is added in an “AddGI” block 408 to be an OFDM signal having a diversity effect and transmitted to the base station 101.

In this case, the carrier component output from the equalizer 404 202a OFDM frequency converter is input to the buffer 405 corresponding to the four different frequency range f ₁ ~f ₄ in 203a, the IFFT processed together at 406 The As a result, the equalizer output signal having the bandwidth f ₀ is shifted to the respective frequency domain, and is combined into an IFFT-processed signal. The signal subjected to the IFFT processing is converted into a time-series signal by P / S conversion in 407, and an GI is added in an “AddGI” block 408 to be an OFDM signal.

  In this way, similar to the above-described OFDM frequency converter 203, the frequency band of the OFDM signal on the input side is different from the frequency band of the OFDM signal on the output side, and a diversity effect can be provided.

  Further, in the configuration of FIG. 4, since the equalizer 404 and the buffer 405 can be inserted between the FFT 403 and the IFFT 406, distortion in the transmission path between the mobile terminal and the repeater device is equalized in the frequency domain and spread over a wide band. It is possible to improve the total communication channel quality between the mobile terminal and the base station.

  Next, an operation flow of uplink transmission including the repeater apparatus according to the present embodiment will be described with reference to FIG.

  The portable terminal 104 transmits an uplink access request to the base station 101 via the uplink transmission path 105 (step S10).

  Next, the base station 101 that has received the access request from the mobile terminal 104 measures propagation loss and searches for and selects an appropriate repeater device in the vicinity of the mobile terminal (step S11), and permits uplink access. Is transmitted to the portable terminal 104 via the downlink transmission path 106 (step S12).

  Further, the base station 101 transmits a relay request to the selected repeater device via the downlink transmission path 108 (step S13).

  Furthermore, the base station 101 transmits control information including parameters used for uplink transmission using the repeater apparatus (step S14), and receives the information by the mobile terminal 104 and the repeater apparatus 103 (steps S15 and S16).

The repeater apparatus 103 uses the received control information for the time slot necessary for the repeater operation, the reception bandwidth f ₀ used for the uplink transmission from the mobile terminal 104 to the repeater apparatus 103, and the uplink transmission from the repeater apparatus to the base station. Each parameter such as shift frequencies f _{1 to} f ₄ to be used is acquired (step S16).

  In this way, the acquired parameters are set in the OFDM signal receiving unit 202 and the OFDM frequency converting unit 203 by the control unit 207 of the repeater apparatus, and new transmission paths 107 and 109 can be used.

  The portable terminal 104 transmits uplink traffic data to the repeater apparatus 103 via the transmission path 109 (step S17), and the OFDM signal frequency-converted by the repeater apparatus 103 is transmitted to the base station 101 via the transmission path 107. (Step S18). The uplink signal transmitted from the repeater apparatus 103 is received by the base station 101, and traffic data is reproduced (step S19).

  Further, control information including parameters used for the next uplink transmission is transmitted from the base station 101 (step S20) and received by the mobile terminal 104 and the repeater apparatus 103 (steps S21 and S22). Here, the repeater apparatus 103 always maintains an appropriate operation state based on the received control information.

<Description of Second Embodiment>
FIG. 6 is a conceptual diagram showing an outline of an operation using an uplink repeater apparatus in the wireless communication system according to the second embodiment of the present invention.

  The system of this embodiment shown in FIG. 6 has a configuration without the downlink transmission path 108 from the base station 101 to the repeater apparatus 103 shown in FIG. 1, and other system components are the same as those in the first embodiment. Is the same.

  The repeater apparatus 600 for OFDM uplink according to the present embodiment is a repeater apparatus that performs in advance setting of control information performed by the repeater apparatus according to the first embodiment so as to operate only for a specific mobile terminal. It is a non-intelligent repeater device that is not based on commands from the base station. For example, it is considered to be installed in a house and used for personal purposes. Further, like the repeater device of the first embodiment, it can be applied to a case where radio wave conditions are very bad and high-speed data transmission from the inside of a building is difficult with low transmission power.

  FIG. 7 is a block diagram of a repeat apparatus 600 according to this embodiment.

  The repeater apparatus 600 for OFDM uplink of this embodiment shown in FIG. 7 has a configuration without the downlink receiving unit 208 that receives control information from the base station from the configuration shown in FIG. The control information recording unit 206 stores in advance information relating to the frequency transmitted from the information terminal and the frequency to be transmitted to the base station. These parameters are not necessarily fixed values, and may be calculated according to a predetermined rule. For example, the second uplink frequency may be determined according to the preamble pattern transmitted from the information terminal. As a result, the downlink reception function for receiving the control signal from the base station can be omitted, and an inexpensive device can be realized. Further, the antenna 201a is for transmission. All other components are the same.

  Accordingly, the repeater apparatus 600 according to the present embodiment does not operate in response to an instruction from the base station 101 as described above, and operates only for a specific mobile terminal 104 as described above. Control information relating to a specific mobile terminal is stored in the control information recording unit 206 in advance. When the operation is started, the control unit 207 reads the control information recorded in advance, and sets each parameter for the OFDM signal reception unit 202 and the OFDM frequency conversion unit 203.

  Next, the operation flow of the uplink system including the repeater apparatus for OFDM uplink according to the present embodiment will be described with reference to FIG.

  First, the mobile terminal 104 transmits an uplink access request and notifies that the repeater apparatus 600 is to be used (step S51). Receiving the uplink access request, the base station 101 notifies the mobile terminal 104 of access permission, other information such as time slot and subcarrier allocation as control information (step S52).

  The portable terminal 104 receives access permission and control information and prepares for uplink transmission using a repeater (step S53).

  On the other hand, for example, the repeater apparatus 600 sets a specific mobile terminal and a terminal-specific preamble simultaneously with power-on, and prepares to convert a frequency-converted OFDM signal from an OFDM signal (step S50).

  In this way, uplink data transmission paths 107 and 109 are established.

  The mobile terminal 104 transmits uplink traffic data to the repeater apparatus 600 via the transmission path 109 (step S54), and the OFDM signal frequency-converted in the repeater apparatus 600 is transmitted to the base station 101 via the transmission path 107. (Step S50). The uplink signal transmitted from the repeater apparatus 600 is received by the base station 101, and the traffic data is reproduced (step S55).

  Further, control information including parameters for the next uplink transmission is transmitted from the base station 101 (step S56), and the mobile terminal 104 receives the control information and prepares for the next uplink transmission (step S57). ).

  As described above, a repeater capable of constructing the system and the system capable of suppressing the power consumption at the time of transmission of the mobile terminal, ensuring the high-speed transmission, and enabling the uplink transmission strong against the frequency selective fading. An apparatus can be provided.

  The uplink repeater apparatus according to the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the scope of the present invention.

  Further, the present invention relates to a repeater device used for uplink transmission, but this does not mean that no repeater is used for the downlink. In addition to the uplink repeater function of the present invention, a repeater device having a downlink repeater function can also be realized. It goes without saying that various changes can be made to a system using a repeater device having a bidirectional repeater function without departing from the gist of the present invention.

It is a conceptual diagram which shows the outline | summary of the radio | wireless communications system using the repeater apparatus for uplink which concerns on 1st Embodiment. 1 is a block diagram of a repeater device according to a first embodiment. It is a figure which shows the relationship of the bandwidth of the input / output used with the repeater apparatus which concerns on 1st Embodiment. FIG. 6 is a block diagram replacing the OFDM signal receiving unit 202, and FIG. 5B is a block diagram replacing the OFDM frequency conversion unit 203. FIG. It is a flowchart which shows operation | movement of the radio | wireless communications system using the uplink repeater apparatus which concerns on 1st Embodiment. It is a conceptual diagram which shows the outline | summary of the radio | wireless communications system using the repeater apparatus for uplink which concerns on 2nd Embodiment. It is a block diagram of the repeater apparatus which concerns on 2nd Embodiment. It is a flowchart which shows operation | movement of the radio | wireless communications system using the repeater apparatus for uplink which concerns on 2nd Embodiment. (A) is a figure which shows the outline | summary of the communication system incorporating the conventional repeater apparatus. (B) is a figure which shows the transmission-and-reception band used with the conventional repeater.

Explanation of symbols

100 public network 101 base station 102 public facility 103, 600 repeater device 104 portable terminal 105 uplink transmission path 106 from portable terminal to base station downlink transmission path 107 from base station to portable terminal 107 repeater device to base station Uplink transmission path 108 Downlink transmission path 109 for control information from the base station to the repeater apparatus 200 Transmission path from the portable terminal to the repeater apparatus 200 Reception antenna 201 Transmission / reception antenna 201a Transmission antenna 202, 202a OFDM signal reception section 203, 203a OFDM frequency Conversion unit 204 Synthesizer 205 Uplink transmission unit 206 Control information recording unit 207 Control unit 208 Downlink reception unit 400 Timing detector 401 GI removal unit 402 S / P
403 FFT
404 Equalizer 405 Buffer 406 IFFT
407 P / S
408 GI addition unit 601 House 800 Frequency bandwidth allocated to uplink 801 Portable terminal 802 Repeater apparatus 803 Base station 804 Uplink transmission path 805 from portable terminal to repeater apparatus Uplink transmission path from repeater apparatus to base station

Claims (5)

A repeater device used when performing uplink transmission from an information terminal to a base station,
An OFDM signal receiving unit having a band-pass filter for removing unnecessary noise components and interference signal components from an OFDM signal having a predetermined bandwidth transmitted from the information terminal;
An OFDM frequency converter that generates an OFDM signal that is wider than the input signal by shifting and combining the OFDM signal having the predetermined bandwidth into a plurality of different frequency regions; and
A control unit that sets parameters necessary for the relay operation and controls the entire apparatus;
A downlink receiver for receiving control information from the base station;
A control information recording unit that extracts and stores parameters such as the predetermined bandwidth and the plurality of frequency regions from the control information; and
The said control part sets the said parameter to the said OFDM signal receiving part and the said OFDM frequency conversion part, and follows the instruction | indication of the control information from the said base station, The repeater apparatus characterized by the above-mentioned. A control information recording unit for recording the parameters necessary for relay operation to the information terminal designated in advance;
Wherein, at the start of operation, by setting the parameter to the OFDM signal receiving section and the OFDM frequency converter, according to claim 1, wherein the relaying operation to the transmission signal of the information terminal the previously specified The repeater apparatus as described in. The frequency region received and processed by the OFDM signal receiving unit is the lowest frequency region among the predetermined uplink bandwidths determined by the wireless communication system and equally divided by a predetermined number,
A plurality of frequency regions is shifted by the OFDM frequency conversion unit, the repeater apparatus according to claim 1 or claim 2, characterized in that a frequency range from the second to the highest order. A frequency gap is provided between the frequency band received by the OFDM signal receiver and the frequency band shifted by the OFDM frequency converter so that the frequency band on the receiving side and the frequency band on the transmitting side do not overlap. the repeater apparatus according to any one of claims 1 to 3, characterized in that. The OFDM signal receiving unit and the OFDM frequency converting unit include discrete components using FFT and IFFT instead of the configuration that directly handles the received OFDM signal,
After extracting the subcarrier components by the FFT OFDM signals thus received, any one of claims 1 to 4, characterized in that it comprises an equalizer for correcting distortion of a wireless transmission path The repeater apparatus as described in.

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