JP2011254380A - Communication system, reception device, relay device, communication method, reception method, and relay method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve transmission efficiency of relay transmission.SOLUTION: The communication system is equipped with: a transmission device 100 which transmits a data signal; a relay device 200 which receives the data signal, amplifies the data signal, and transmits the amplified signal; and a reception device 300 which receives signals from the transmission device 100 and the relay device 200. The reception device 300 transmits a control signal indicating an amplification factor or the presence/absence of amplification to the relay device 200. The relay device 200 changes the amplification factor or starts or stops the amplification on the basis of the control signal.

Description

  The present invention relates to a communication system, a receiving device, a relay device, a communication method, a receiving method, and a relay method.

  The base station apparatus is a communication apparatus arranged throughout the country with a predetermined distance interval in order to enable communication between mobile station apparatuses that are a large number of user terminals. In a mobile communication system such as a cellular phone, for example, when a base station device is arranged in an urban area, a communication range (one base station device can connect to the mobile station device due to the occurrence of a blind area or a weak electric field area such as a building shadow) (Area) is reduced or a signal to noise ratio (SNR) of a signal received by a mobile station apparatus connected to the base station apparatus in the area is reduced. Further, as the transmission rate is required to be increased, the system band shifts to a high frequency band, so that the area that can be covered by one base station apparatus is reduced.

  As means for realizing the elimination of these insensitive areas or weak electric field areas with low introduction and operation costs, there are transmission methods called repeater transmission or AF (Amplify-and-Forward) relay transmission. Hereinafter, this transmission method is referred to as “relay transmission”. In relay transmission, repeaters or AF relay stations (hereinafter collectively referred to as relay station devices (relay devices)) are arranged in a place with relatively good visibility from both base station devices and insensitive areas or weak electric field areas. Realize.

  The relay station apparatus (relay apparatus) outputs the received radio signal after amplification without performing digital signal processing such as demodulation. For example, in the case of downlink, after amplifying a radio signal received from a base station apparatus (transmitting apparatus), the signal is transmitted to a mobile station apparatus (receiving apparatus) in a dead area or a weak electric field area. In the above-described relay transmission, the radio signal received by the mobile station apparatus is composed of a signal directly coming from the base station apparatus and a signal coming via the relay station apparatus (relay apparatus) (see Non-Patent Document 1). .

  FIG. 24 is a diagram illustrating relay transmission in a downlink, which is a radio channel from a base station apparatus to a mobile station apparatus, in a conventional communication system. The mobile station device 1002 transmits the signal transmitted from the base station device 1000 to the mobile station device 1002 from the base station device 1000, the route rr1 not via the relay station device 1001, and from the base station device 1000 to the relay station device 1001. Route rr2 and the route rr3 from the relay station device 1001 to the mobile station device 1002, or both of the routes. An environment in which the mobile station device 1002 can receive only from the route rr3 is called a closed space, and an environment in which the mobile station device 1002 can receive from both the route rr1 and the route rr3 is called an open space.

  The signal received by the mobile station device 1002 through the route rr3 is a signal output after the relay station device 1001 amplifies and filters (band-limits) the signal received from the base station device 1000 through the route rr2. Then, the arrival time of the signal arriving through the path rr3 is delayed from the signal arriving through the path rr1 due to processing delay caused by amplification and filtering in the relay apparatus.

  Here, consider a case where base station apparatus 1000 transmits an OFDM (Orthogonal Frequency Division Multiplexing) modulated signal (hereinafter referred to as an OFDM signal). The influence of multipath fading in high-speed digital signal transmission can be reduced by making the OFDM signal multicarrier and inserting a guard interval (GI).

  In Non-Patent Document 1, when a repeater (relay device) is arranged in a small base station (cell) that forms a communication area in a small range with a radius of about 10 meters, the mobile station receives signals and repeaters that arrive directly from the base station. It is disclosed that both of the signals that have passed through are received, and the latter signal arrives with a delay of the processing delay time of the repeater from the former signal.

  In Non-Patent Document 2, when a repeater (relay device) is arranged in a cell, a signal passing through the repeater arrives at the mobile station with a delay of the repeater processing delay time from a signal directly coming from the base station, and the processing delay time It is disclosed that when I exceeds the GI length, ISI and ICI are generated and cause deterioration of characteristics.

  On the other hand, Non-Patent Document 3 specifies two types of long and short CPs (Cyclic Prefix: Cyclic Prefix, GI alias) in the system as a countermeasure against the characteristic degradation disclosed in Non-Patent Document 2. It is disclosed that it can be avoided by using a long CP.

"3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Universal Terrestrial Radio Access (UTRA) repeater planning guidelines and system analysis (Release 7)" 3GPP TR25.956 v7.0.0 (2007-06) R4-071917, 3GPP TSG-RAN WG4 (Radio) Meeting # 45 Jeju, Korea, 5-9 November, 2007 URL: http://www.3gpp.org/ftp/tsg_ran/WG4_Radio/TSGR4_45/Docs/ Report of the 3GPP TSG RAN WG4 meeting number 45 Jeju, Korea, 5-9 November 2007 URL: http://www.3gpp.org/ftp/tsg_ran/WG4_Radio/TSGR4_45/Report/

  However, if there is a delayed wave exceeding the guard interval interval, intersymbol interference (ISI: Inter Symbol Interference) caused by the preceding symbol entering the Fast Fourier Transform (FFT) interval, or the Fast Fourier Transform interval. Inter-carrier interference (ICI: Inter-Carrier Interference) occurs due to symbol breaks, that is, when a signal discontinuous section enters, causing transmission characteristics to deteriorate.

  In the relay transmission of FIG. 24, when the processing time of the relay station device 1001 is longer than the GI length, a signal received by the mobile station device 1002 from the relay station device 1001 through the route rr3 is transmitted from the base station device 1000 to the route rr1. It arrives with a delay of GI length or more from the signal received through (see Non-Patent Document 2). For this reason, ISI and ICI occur, and transmission characteristics deteriorate.

  As a method for improving the characteristic deterioration due to these ISI and ICI, a method is described in which an OFDM signal to which a GI (Long GI) longer than the processing time of the relay station apparatus is added is transmitted (Non-Patent Document 2 and Non-Patent Document 2). Reference 3). By this method, interference can be suppressed by making the arrival time difference fall within the GI length. However, in Non-Patent Document 2 and Non-Patent Document 3, when relay transmission is performed, since a GI longer than usual is used, there is a problem that the insertion loss of GI increases and the transmission efficiency decreases.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a communication system, a reception device, a relay device, a communication method, a reception method, and a relay method that improve transmission efficiency in relay transmission.

  (1) The communication system of the present invention has been made in view of the above circumstances, and a transmission device that transmits a data signal, and a relay device that receives the data signal, amplifies the data signal, and transmits the amplified signal. And a receiving device that receives the amplified signal, wherein the receiving device transmits a control signal instructing an amplification factor or presence / absence of amplification to the relay device, and the relay device transmits the control signal to the control signal. Based on this, the amplification factor is changed, or amplification is started or stopped.

  (2) In the communication system according to (1), the control signal includes information indicating a frequency band for setting the amplification factor or setting of the presence / absence of amplification to the relay device.

  (3) In the communication system according to (2), the control signal includes information instructing to change an amplification factor of a frequency band assigned to the data signal transmitted to the receiving device. .

  (4) In the communication system according to (2), the relay station apparatus sets a frequency band through which the data signal passes based on the control signal.

  (5) In the communication system according to any one of (1) to (4), the transmission device is a base station device, and the reception device is a mobile station device.

  (6) In the communication system according to any one of (1) to (4), the communication system includes a plurality of the reception devices, and the relay device controls an amplification factor for each individual reception device. It is characterized by performing.

  (7) In the communication system according to any one of (1) to (4), the transmission device is a mobile station device, and the relay device is a plurality of base station devices.

  (8) In the communication system according to any one of (1) to (7), when the receiving device receives a delayed wave exceeding a predetermined period, the control signal is sent to the relay station device. It is characterized by transmitting.

  (9) In the communication system according to (8), the control signal includes information instructing to lower the amplification factor.

  (10) In the communication system according to (8), the control signal includes information instructing to stop the amplification.

  (11) The receiving device of the present invention has been made in view of the above circumstances, and determines whether a receiving unit that receives a data signal and whether the data signal is a delayed wave signal exceeding a predetermined period. A quality determination unit; and a control signal generation unit that generates a control signal instructing an amplification factor of the data signal or presence / absence of amplification based on the determination of the quality determination unit.

  (12) The relay device of the present invention has been made in view of the above circumstances, and transmits a reception unit that receives a data signal and a control signal, an amplification unit that amplifies the data signal, and a signal amplified by the amplification unit. And a control signal detection unit that detects information indicating the amplification factor or the presence / absence of amplification from the control signal, and the amplification unit changes the amplification factor based on the information or starts amplification Or it stops.

  (13) The communication method of the present invention has been made in view of the above circumstances. In a communication method in a communication system having a transmission device, a relay device, and a reception device, a transmission step of transmitting a data signal, and the relay device Receiving the data signal, amplifying the data signal, and transmitting the amplified signal; a receiving step in which the receiving device receives the amplified signal; and the receiving device, A transmission step of transmitting a control signal indicating the amplification factor or the presence or absence of amplification to the relay device; an amplification changing step in which the relay device changes the amplification factor based on the control signal, or starts or stops amplification; It is characterized by having.

  (14) The reception method of the present invention has been made in view of the above circumstances, and the quality determination step of determining whether or not the received data signal is a signal due to a delayed wave exceeding a predetermined period; And a control signal generation step of generating a control signal instructing the amplification factor of the data signal or the presence / absence of amplification based on the determination in the quality determination step.

  (15) The relay method of the present invention has been made in view of the above circumstances, and an amplification step in which the relay device amplifies the received data signal, and a transmission step in which the relay device transmits the signal amplified in the amplification step. A control signal detecting step for detecting information indicating the amplification factor or the presence / absence of amplification from the control signal received by the relay device, and the relay device changing the amplification factor based on the information, or starting amplification or And an amplification changing step for stopping.

  According to the present invention, transmission efficiency can be improved in relay transmission.

It is a figure which shows the outline of the communication system which concerns on the 1st Embodiment of this invention. It is a sequence diagram which shows communication of the signal of a base station apparatus, a relay station apparatus, and a mobile station apparatus. It is a flowchart which shows operation | movement of a mobile station apparatus. It is an example which shows the impulse response of the propagation path between a base station and a mobile station. It is another example which shows the impulse response of the propagation path between a base station and a mobile station. 6 is an impulse response of a retransmitted information data radio signal to the information data radio signal indicating the impulse response of FIG. 5. It is a flowchart which shows operation | movement of a relay station apparatus. It is a functional block diagram which shows the example of 1 structure of the base station apparatus which concerns on the 1st Embodiment of this invention. It is the figure which showed the example of a mapping of the data modulation symbol in the case of performing OFDM transmission, a control symbol, and a pilot symbol. It is a functional block diagram which shows one structural example of the relay apparatus which concerns on the 1st Embodiment of this invention. It is a functional block diagram which shows the example of 1 structure of the mobile station apparatus which concerns on the 1st Embodiment of invention. It is a figure for demonstrating the judgment method of whether the long delay wave exceeding GI length exists in a threshold value. It is a figure shown about the communication system which concerns on the 2nd Embodiment of this invention. It is the figure which showed the radio signal of the information data which a base station apparatus transmits. It is a sequence diagram which shows communication of the signal between the base station apparatus in 2nd Embodiment, a relay station apparatus, and a mobile station apparatus. It is a flowchart which shows operation | movement of a relay station apparatus. FIG. 6 is a diagram illustrating a radio signal of information data that is retransmitted by the relay station apparatus after the relay station apparatus receives the relay apparatus control signal from the mobile station apparatus. It is a functional block diagram which shows the example of 1 structure of the base station apparatus which concerns on the 2nd Embodiment of this invention. It is a functional block diagram which shows the example of 1 structure of the relay station apparatus which concerns on the 2nd Embodiment of this invention. It is a functional block diagram which shows the example of 1 structure of the mobile station apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the user allocation at the time of a base station apparatus transmitting data to a mobile station apparatus or a relay station apparatus in the downlink which carries out OFDMA transmission. It is the figure which showed the communication system which concerns on the 3rd Embodiment of this invention. It is a sequence diagram which shows communication of the signal between the base station apparatus in 3rd Embodiment, a relay station apparatus, and a mobile station apparatus. It is the figure which showed the relay transmission in a downlink in the conventional communication system.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<First Embodiment>
[Communications system]
FIG. 1 is a diagram showing an outline of a communication system according to the first embodiment of the present invention. The communication system in FIG. 1 includes a base station device 100 (transmitting device), a relay station device 200 (relay device), and a mobile station device 300 (receiving device).

  In FIG. 1, r1 is a path through which a radio signal transmitted from the base station apparatus 100 directly reaches the mobile station apparatus 300, r2 is a path through which a radio signal transmitted from the base station apparatus 100 reaches the relay station apparatus 200, and r3 is a base station. This is a path between the relay station apparatus 200 and the mobile station apparatus 300 when the radio signal transmitted by the station apparatus 100 reaches the mobile station apparatus 300 via the relay station apparatus 200. R4 is a path through which the control signal (relay device control signal) transmitted from the mobile station device 300 for controlling the relay station device 200 reaches the relay station device 200.

  Although the base station apparatus may be referred to as a transmission apparatus, the present invention is not limited to this, and includes a case where a mobile station apparatus is referred to as a transmission apparatus. In addition, the mobile station apparatus may be referred to as a receiving apparatus, but the present invention is not limited to this, and includes a case where the apparatus is referred to as a receiving apparatus.

Base station apparatus 100 transmits information data and control data to mobile station apparatus 300 by radio signals (RF signals). The relay station apparatus 200 amplifies and filters the radio signal received from the base station apparatus 100 and outputs the amplified signal.
The mobile station device 300 receives the information data and control data radio signals transmitted by the base station device 100 from the route r1, the route r3, or both. Then, according to the reception status, the mobile station device 300 controls the relay station device 200 by transmitting the relay device control signal to the relay station device 200 via the route r4.

  Note that a wireless line is used as the route r2 between the base station apparatus 100 and the relay station apparatus 200. However, a wired line such as an optical fiber (for example, a remote radio equipment (RRE: Remote Radio Equipment)) is used. Also good.

  FIG. 2 is a sequence diagram showing signal communication between base station apparatus 100, relay station apparatus 200, and mobile station apparatus 300. In FIG. 2, the mobile station apparatus 300 is described as having completed link connection between the mobile station apparatus 300 and the base station apparatus 100 based on control data (for example, random access channel, paging, etc.) with the base station apparatus 100. To do.

  The base station apparatus 100 transmits a radio signal of information data to the mobile station apparatus 300, and the mobile station apparatus 300 directly (route r1) from the base station apparatus 100 and via the relay station apparatus 200 (paths r2 and r3). The wireless signal of the information data is received from both (step T101). The mobile station device 300 determines whether or not a signal has been correctly received with respect to the radio signal of the information data (step T102). Then, the mobile station apparatus 300 notifies the base station apparatus 100 of an ACK / NACK (Acknowledgement / Negative Acknowledgment) signal indicating whether or not the radio signal of the information data has been correctly received (step T103).

Also, when the mobile station device 300 cannot correctly receive the information data radio signal, the mobile station device 300 extracts the propagation path estimation pilot signal inserted in the received data signal from the information data radio signal, Reception quality is calculated based on the propagation path estimation pilot signal (T102).
Then, the mobile station apparatus 300 transmits a control signal (relay apparatus control signal) for controlling the amplification factor to the relay station apparatus 200 based on the reception quality (path r4, step T104). Here, the relay device control signal is a signal indicating an amplification factor or a signal for instructing start or stop of amplification. The relay device control signal may be a signal for notifying that amplification is stopped (amplification factor is zero).

  The relay station device 200 changes the amplification factor based on the relay device control signal received from the mobile station device 300 (step T105). Then, when base station apparatus 100 transmits a radio signal of information data to relay station apparatus 200 again, mobile station apparatus 300 receives the relay station apparatus subjected to signal amplification directly from base station apparatus 100 and different from step T101. The signal via 200 is received (T106).

  When the relay device control signal is a signal notifying that the amplification of the relay station device 200 is stopped, the mobile station device 300 receives a direct signal from the base station device 100. In this case, the control signal for the relay device is a signal for notifying that the amplification factor is lowered for a certain period or a signal for notifying amplification for a certain period.

[Operation of mobile station device]
FIG. 3 is a flowchart showing the operation of the mobile station apparatus 300. In FIG. 3, as in FIG. 2, description will be made assuming that link connection is completed between mobile station apparatus 300 and base station apparatus 100.

  When the mobile station device 300 receives a radio signal of information data from the base station device 100 (step S101), the mobile station device 300 performs signal detection processing such as demodulation processing and decoding processing, and acquires information data (step S102). Then, an error detection process is performed on the signal detection process result, and it is determined whether or not there is a data error in the radio signal of the information data (step S103).

When there is no data error in the information data radio signal (NO in step S103), the mobile station device 300 generates a signal (ACK signal) notifying that the information has been correctly received, and transmits the signal to the base station device 100 ( Step S104).
On the other hand, when there is a data error in the radio signal of the information data (step S103 YES), the mobile station device 300 generates a signal (NACK signal) notifying that it has not been received correctly, and the NACK signal is transmitted to the base station device. Transmit to 100 (step S105). As a result, the mobile station apparatus 300 requests retransmission of a radio signal of information data.

  Furthermore, mobile station apparatus 300 determines whether or not a delayed wave exceeding GI has arrived based on an impulse response calculated from a propagation path estimation pilot signal included in the radio signal from base station 100 (step S106). ). If there is a delay wave exceeding GI (YES in step S106), mobile station apparatus 300 generates a relay apparatus control signal notifying that the amplification is to be stopped, and transmits the relay apparatus control signal to relay station apparatus 200. (Step S107). Then, the mobile station apparatus 300 waits for arrival of a radio signal of information data to be retransmitted.

  When the relay station device 200 stops amplification, the power of the signal arriving at the mobile station device 300 via the path r3 in FIG. 1 can be made smaller than the detection limit. That is, the mobile station device 300 detects only a signal that arrives through the route r1. As a result, even if the mobile station device 300 receives both the signal arriving through the route r1 and the signal arriving through the route r3, the mobile station device 300 determines that the signal arriving through the route r3 It is possible to avoid the generation of a super delayed wave exceeding the GI length due to the arrival delay from the signal arriving through r1.

  On the other hand, when there is no arrival of a delayed wave exceeding GI (NO in step S106), mobile station apparatus 300 waits for arrival of a radio signal of information data to be retransmitted. Above, the process of this flowchart is complete | finished.

  FIG. 4 is an example illustrating an impulse response of a propagation path between the base station 100 and the mobile station 300. The horizontal axis is time t, and the vertical axis is the power level. w1-1 is an impulse response of the path r1 that the mobile station apparatus 300 reaches directly from the base station apparatus 100, and w2-1 is an impulse response of the path r2 and the path r3 that reach via the relay station apparatus 200.

  Here, if the received power of the impulse response w1-1 is smaller than a predetermined detection threshold, the mobile station device 300 does not detect the impulse response w1-1. The mobile station apparatus 300 performs signal detection processing in FFT synchronization with the impulse response w2-1. Therefore, the mobile station device 300 does not receive a delayed wave exceeding the GI length. In addition, since there is little interference due to the impulse response w1-1, characteristic deterioration of the impulse response w2-1 can be suppressed. In this case, in step S106, the mobile station device 300 determines that there is no arrival of a delayed wave exceeding the GI length.

  FIG. 5 is another example showing an impulse response of a propagation path between the base station 100 and the mobile station 300. The horizontal axis is time t, and the vertical axis is the power level. w1-2 is a radio signal of the impulse response of the route r1 that the mobile station device 300 reaches directly from the base station device 100, and w2-2 is the impulse response of the route r2 and the route r3 that reach via the relay station device 200. .

  In this case, since the reception power of the impulse response w1-2 is large enough to establish FFT synchronization, the mobile station device 300 performs signal detection processing in FFT synchronization with the impulse response w1-2. As a result, the impulse response w2-2 becomes a delayed wave exceeding the GI length. Therefore, in step S106 of FIG. 3, the mobile station device 300 determines that there is a delay wave exceeding the GI, and notifies the relay station device 200 that the amplification is stopped.

  FIG. 6 is an impulse response of a propagation path when information data is retransmitted with respect to a radio signal of information data indicating the impulse response of FIG. The horizontal axis is time t, and the vertical axis is the power level. w1-2 is an impulse response of the path r1 that the mobile station apparatus 300 reaches directly from the base station apparatus 100, and w'2-2 is an impulse response of the path r2 and the path r3 that reach via the relay station apparatus 200. As a result of the mobile station apparatus 300 notifying the relay station apparatus 200 that the amplification is stopped, the relay station apparatus 200 has stopped the amplification, so that the power level of the impulse response w′2-2 is lowered. Accordingly, since the power level of the delayed wave exceeding the GI length is lowered, ISI and ICI generated at the time of signal detection are suppressed, and the characteristics can be improved.

  5 and 6, the setting of the amplification factor of the relay station apparatus is controlled based on the presence / absence of the delayed wave exceeding the GI length, but the determination may be made based on the power level of the delayed wave exceeding the GI length. In that case, for example, a threshold value of a certain power level is set, and when the power level of the delayed wave exceeding the GI length is larger than the threshold value, the amplification is stopped.

[Operation of relay station equipment]
FIG. 7 is a flowchart showing the operation of relay station apparatus 200. When relay station apparatus 200 receives the signal (radio signal of information data) transmitted from base station apparatus 100 (YES in step S201), relay station apparatus 200 extracts the frequency band to be amplified, and based on the currently set amplification factor, The signal is amplified (step S202). Then, relay station apparatus 200 removes components that become unnecessary radiation (spurious) generated around the amplified frequency band by filtering (step S202), and transmits the signal from which spurious has been removed to mobile station apparatus 300 (step S203). ).

  When relay station apparatus 200 has not received the signal transmitted from base station apparatus 100 (NO in step S201), relay station apparatus 200 receives the relay apparatus control signal transmitted from mobile station apparatus 300. It is determined whether or not (step S204). When the relay station control signal transmitted from the mobile station apparatus 300 has not been received (NO in step S204), the relay station apparatus 200 returns to the process of step S201.

  On the other hand, when the relay device control signal transmitted from mobile station device 300 is received (YES in step S204), demodulation processing and decoding processing are performed for error correction coding and modulation applied to the relay device control signal. I do. For example, when mobile station apparatus 300 transmits a control signal subjected to convolutional coding and QPSK (Quadrature Phase Shift Keying) modulation to relay station apparatus 200, relay station apparatus 200 demodulates the QPSK modulation. Processing and decoding processing for convolutional coding are performed.

  Then, relay station apparatus 200 extracts control data related to amplification factor control from the demodulated and decoded signals (step S205). Then, according to the instruction included in the control data, relay station apparatus 200 changes the setting of the amplification factor of the amplification unit of relay station apparatus 200 (step S206), and waits for the next signal from base station apparatus 100. . Above, the process of this flowchart is complete | finished.

[Configuration of base station apparatus]
FIG. 8 is a functional block diagram showing a configuration example of the base station apparatus 100 according to the first embodiment of the present invention. In addition, in FIG. 8, although the case where the radio signal transmitted by the base station apparatus is an OFDM signal will be described, a single carrier such as SC-FDMA (Single Carrier-Frequency Multiple Access: single carrier frequency division multiple access) ( It can also be applied to a single carrier) system. The same applies to the following embodiments.

  The base station apparatus 100 includes an antenna unit 101, a symbol generation unit 112, a resource mapping unit 106, an IFFT (Inverse Fast Fourier Transform) unit 107, a GI insertion unit 108, a transmission unit 109, and a control signal generation unit 110. And a pilot signal generation unit 111. Here, the antenna unit 101 is connected to the transmission unit 109. The symbol generation unit 112 includes an error detection code unit 102, an error correction code unit 103, an interleave unit 104, and a modulation unit 105.

  When part or all of the base station apparatus 100 is configured by a single or a plurality of chips using a semiconductor integrated circuit, it has a chip control circuit (not shown in the figure) that controls each functional block. .

  The error detection coding unit 102 performs CRC on information data input from a higher layer (not shown) (a layer having a function located in a higher layer such as a MAC layer (Media Access Control) or a network layer). Encoding for error detection is performed on the receiving side such as (Cyclic Redundancy Check). The error detection encoding unit 102 supplies the error detection encoded information data to the error correction encoding unit 103. Note that the error detection code unit 102 may be incorporated in a part of the upper layer.

  The error correction code unit 103 applies any one of turbo code, LDPC (Low Density Parity Check), convolutional code, etc. to the error detection coded information data supplied from the error detection code unit 102. The error correction encoding process is performed. Here, the information data after the error correction coding process is referred to as a coded bit. The error correction coding unit 103 supplies the coded bits to the interleaving unit 104.

  The interleaving unit 104 changes the arrangement order of the encoded bits supplied from the error correction encoding unit 103 in order to improve the occurrence of a burst error due to a drop in received power due to frequency selective fading. Interleaving section 104 then supplies the encoded bits whose arrangement order has been changed to modulation section 105.

  The modulation unit 105 maps the coded bits supplied from the interleaving unit 104 whose arrangement order has been changed to modulation symbols, and BPSK (Binary Phase Shift Keying), QPSK, 16QAM (16 Quadrature Amplitude). Data modulation symbols such as Modulation: 16-value quadrature amplitude modulation) and 64 QAM (64 Quadrature Amplitude Modulation) are generated. Then, modulation section 105 supplies the generated data modulation symbol to resource mapping section 106.

  The control signal generation unit 110 performs error correction coding and modulation on various control data such as MCS (Modulation and Coding Scheme) information and rank information related to a radio signal of information data output from an upper layer. Perform mapping and generate control symbols. Then, the control signal generation unit 110 supplies the generated control symbol to the resource mapping unit 106.

  Here, the MCS information is information indicating a coding rate and a modulation scheme applied to a radio signal of information data. The rank information is information indicating the number of multiplexed spatial multiplexed signals (MIMO (Multi Input Multiple Output) signals) applied to the information data radio signal. The modulation mapping is a modulation process such as QPSK.

  Pilot signal generating section 111 generates pilot symbols for the reception side to estimate the propagation path. For example, the pilot symbols are signal sequences of “1” and “−1” which are Hadamard codes. Here, the code sequence constituting the pilot symbol may be a code sequence known between the mobile station device 300 and the relay station device 200, but is orthogonal such as Hadamard code, CAZAC (Constant Amplitude Zero Auto-Correlation) sequence, etc. A series is preferred. Pilot signal generation section 111 then supplies the generated pilot symbols to resource mapping section 106.

  The resource mapping unit 106 maps the data modulation symbols supplied from the modulation unit 105, the control symbols supplied from the control signal generation unit 110, and the pilot symbols supplied from the pilot signal generation unit 111 to subcarriers. The resource mapping unit 106 supplies the signal after mapping to the subcarrier to the IFFT unit 107.

  FIG. 9 is a diagram illustrating an example of mapping of data modulation symbols, control symbols, and pilot symbols when performing OFDM transmission. The vertical axis represents frequency and the horizontal axis represents time. A range composed of one subcarrier and one OFDM symbol is called a resource element. The white area is a resource element mapping data modulation symbols, the grid area is a resource element mapping control symbols, and the shaded area is a resource element mapping pilot symbols.

  Returning to FIG. 8, IFFT section 107 performs IFFT (Inverse Fast Fourier Transform) processing on the signal mapped to the subcarrier supplied from resource mapping section 106, thereby converting each symbol in the frequency domain. Convert signal to time domain signal. The IFFT unit 107 supplies the converted time domain signal to the GI insertion unit 108.

  The GI insertion unit 108 adds a guard interval (GI) to the time domain signal converted by the IFFT unit 107. For example, the GI insertion unit 108 copies a part of the latter half of the time domain signal (effective symbol) supplied from the IFFT unit 107 and adds it to the head of the effective symbol. Here, an effective symbol to which GI is added is called an OFDM symbol. If the signal output from the GI insertion unit 108 is s (t), it can be expressed by the following equation (1).

Here, Nf is the number of IFFT points, ck, l are symbols assigned to the kth subcarrier of the lth OFDM symbol, Δf is the frequency interval of the subcarrier, Ts is the OFDM symbol length (including GI length), j is an imaginary unit.
The GI insertion unit 108 supplies the signal with the GI added to the transmission unit 109.

  The transmission unit 109 converts the signal added with the GI supplied from the GI insertion unit 108 from a digital signal to an analog signal. Then, the transmission unit 109 performs a filtering process that performs band limitation on the signal converted into the analog signal, and further up-converts the filtered signal to a frequency band that can be transmitted. Then, the transmission unit 109 amplifies the up-converted signal with a power amplifier or the like, and transmits the amplified signal via the transmission antenna unit 101.

[Relay station equipment]
FIG. 10 is a functional block diagram showing a configuration example of the relay apparatus 200 according to the first embodiment of the present invention. The relay apparatus 200 includes a reception antenna unit 201, a reception unit 202, an amplification unit 203, a filter unit 204, a transmission unit 205, a transmission antenna unit 206, and a control signal detection unit 207. When a part or all of the relay device 200 is configured by a single or a plurality of chips using a semiconductor integrated circuit, it has a chip control circuit (not shown in the figure) that controls each functional block. .

The receiving unit 202 receives a radio signal of information data transmitted from the base station apparatus 100 via the receiving antenna unit 201, and down-converts it to a frequency band that can be amplified. Then, the reception unit 202 supplies the radio signal of the down-converted information data to the amplification unit 203.
Also, the receiving unit 202 receives a relay device control signal transmitted by the mobile station device 300 described later via the receiving antenna unit 201, and down-converts it to a frequency band in which signal detection processing is possible. Then, the reception unit 202 supplies the downconverted relay device control signal to the control signal detection unit 207.

  The control signal detection unit 207 performs signal detection processing such as demodulation processing and decoding processing on the downconverted relay device control signal supplied from the reception unit 202. The control signal detection unit 207 extracts the relay device control information about the amplification factor to be set or the presence / absence of amplification by the signal detection process, and supplies the extracted relay device control information to the amplification unit 203.

  The amplification unit 203 sets an amplification factor based on the relay device control information supplied from the control signal detection unit 207. Then, the amplification unit 203 amplifies the radio signal of the down-converted information data supplied from the reception unit 202 for a certain period according to the set amplification factor, and supplies the amplified signal to the filter unit 204. Alternatively, the amplifying unit 203 does not amplify the radio signal of the down-converted information data for a certain period and supplies it to the filter unit 204 as it is.

The filter unit 204 removes spurious and applies a band-limited filter to the signal supplied from the amplification unit 203. The filter unit 204 supplies the filtered signal to the transmission unit 205.
The transmission unit 205 up-converts the frequency of the filtered signal supplied from the filter unit 205 and transmits it through the transmission antenna unit 206.

[Configuration of mobile station device]
FIG. 11 is a functional block diagram showing a configuration example of the mobile station apparatus 300 according to the first embodiment of the present invention. The mobile station apparatus 300 includes a reception antenna unit 301, a reception unit 302, a GI removal unit 303, an FFT unit 304, a propagation path compensation unit 305, a resource demapping unit 306, a demodulation unit 307, and a deinterleaving unit. 308, a decoding unit 309, an error detection unit 310, a propagation path estimation unit 311, a quality judgment unit 312, a control signal generation unit 313, a transmission unit 314, and a transmission antenna unit 315. When a part or all of the receiving device 300 is configured by a single or a plurality of chips using a semiconductor integrated circuit, it has a chip control circuit (not shown in the figure) that controls each functional block. .

  Receiving section 302, when receiving a radio signal of information data transmitted from base station apparatus 100 and relay station apparatus 200 via receiving antenna section 301, down-converts it to a frequency band capable of digital signal processing such as signal detection processing. Further, filtering processing for removing spurious is performed, and the filtered signal is converted from an analog signal to a digital signal. The reception unit 302 supplies the converted digital signal to the GI removal unit 303 and the propagation path estimation unit 311.

  The propagation path estimation unit 311 estimates (propagation path estimation) the amount of fluctuation in received signal amplitude and phase due to fading or the like while reaching the mobile station apparatus 300 through the path r1, the path r2, and the path r3. Then, propagation path estimation section 311 sends the received signal amplitude and phase fluctuation estimation values obtained by propagation path estimation (hereinafter referred to as propagation path estimation values) to propagation path compensation section 305 and quality determination section 312. Supply.

  Here, propagation path estimation section 311 performs propagation path estimation using pilot symbols that are known signals mapped to subcarriers included in the signal output from reception section 302. Specifically, for example, propagation path estimation section 311 arranges pilot symbols by dividing pilot symbols mapped to subcarriers by the same signal sequence as pilot symbols held by mobile station apparatus 300. The frequency response of the subcarriers calculated is calculated. Then, the propagation path estimation unit 311 calculates the propagation path estimation of the subcarriers where pilot symbols are not arranged by performing interpolation processing such as linear interpolation using the frequency response of the subcarriers where pilot symbols are arranged. .

  The GI removal unit 303 removes the guard interval section added by the base station device 100 in order to avoid distortion due to the delayed wave, from the radio signal of the information data supplied from the reception unit 302. The GI removal unit 303 supplies the radio signal of the information data from which the guard interval section is removed to the FFT unit 304.

  The FFT unit 304 performs a Fourier transform that converts the radio signal of the information data from which the guard interval section supplied from the GI removal unit 303 is removed from a time domain signal to a frequency domain signal. The FFT unit 304 supplies the frequency domain signal after the Fourier transform to the propagation path compensation unit 305.

  The propagation path compensation unit 305 uses the propagation path estimation value supplied from the propagation path estimation unit 311 to calculate a weighting factor for correcting propagation path distortion due to fading using ZF (Zero Forcing), MMSE (Minimum Mean Square Error), or the like. Then, the frequency domain signal supplied from the FFT unit 305 is multiplied by this weight coefficient. Accordingly, the propagation path compensation unit 305 can correct propagation path distortion (propagation path compensation). The propagation path compensation unit 305 supplies the calculated corrected signal to the resource demapping unit 306.

  The resource demapping unit 306 performs demapping processing on the corrected signal supplied from the propagation path compensation unit 305. Here, the demapping process is a process of extracting a necessary signal from signals mapped to subcarriers. That is, a data modulation symbol is extracted. The resource demapping unit 306 supplies the demapped signal to the demodulation unit 307.

  The demodulation unit 307 performs demodulation processing on the modulation performed in the modulation unit 105 of the base station apparatus 100 on the demapped signal supplied from the resource demapping unit 306, and performs a hard decision value or a soft decision value ( The coded bit LLR) is calculated. The demodulator 307 supplies the calculated data series (hard decision value or soft decision value) to the deinterleaver 308.

  The deinterleaving unit 308 rearranges the bit arrangement corresponding to the interleaving pattern performed by the interleaving unit 104 of the transmission source base station apparatus 100, that is, the bit arrangement rearrangement that is the reverse operation of the interleaving pattern. This is performed on the data series supplied from. The deinterleaving unit 308 supplies the data sequence in which the bit arrangement is rearranged to the decoding unit 309.

  In the decoding unit 309, the bit arrangement supplied from the deinterleaving unit 308 is rearranged for error correction decoding processing for error correction coding such as turbo coding and convolution coding performed by the base station apparatus 100 that is the transmission source. Perform on data series. The decoding unit 309 supplies the signal after error correction decoding processing to the error detection unit 310.

  The error detection unit 310 performs error detection processing for error detection coding performed by the base station apparatus 100 that is a transmission source on the signal after error correction decoding processing supplied from the decoding unit 309, and converts the received information data into the received information data Determine if there is an error. The error detection unit 310 supplies information about whether or not there is an error to the quality determination unit 312. Note that the error detection unit 310 may be incorporated in an upper layer (not shown) included in the mobile station 300.

  The quality determination unit 312 converts the frequency response supplied from the propagation path estimation unit 311 into an impulse response, and determines whether there is a delayed wave exceeding the GI length using the converted impulse response. The quality determination unit 312 determines the current reception quality using the determination result whether there is a delayed wave exceeding the GI length and the information whether there is an error supplied from the error detection unit 310. . Alternatively, the quality determination unit 312 calculates the power level of the delayed wave exceeding the GI length, and determines the current reception quality (for details, refer to FIGS. 3, 4, 5, and 6 and their descriptions). The quality determination unit 312 supplies the determination result to the control signal generation unit 313.

  Based on the determination result supplied from the quality determination unit 312, the control signal generation unit 313 generates a relay device control signal for instructing the relay station device 200 to set the amplification factor. The control signal generator 313 receives the error detection result supplied from the error detector 310 and generates an ACK signal or a NACK signal. The control signal generation unit 313 supplies the relay device control signal or the ACK signal / NACK signal to the transmission unit 314.

  The transmission unit 314 up-converts the frequency of the relay device control signal or the ACK signal / NACK signal supplied from the control signal generation unit 313 to a radio frequency. Transmitter 314 transmits the upconverted signal via antenna 315.

Subsequently, a method for determining the amplification factor that the control signal generation unit 313 instructs the relay station apparatus 200 and the effect thereof will be described.
(1) The mobile station apparatus 300 performs demodulation, decoding processing, and error detection processing on the data signal addressed to the own user. When an error is detected, the propagation path estimation unit 311 is supplied from the propagation path estimation unit 311. Based on the obtained frequency response, the impulse response (delay profile) of the received signal is calculated.

  (2) The quality determination unit 312 determines that the amplification of the relay station device 200 is stopped when there is a delayed wave exceeding the GI length in the impulse response. According to this determination result, the cause of the data error in (1) is intersymbol interference (ISI) and intercarrier interference (ICI) due to the long delay wave (w2-2 in FIG. 5) exceeding the GI length, and the super delay This is because it can be determined that the probability that the wave is generated by the signal from the relay station apparatus 200 is high.

  The presence / absence of a delay wave exceeding the GI length is determined by, for example, the quality determination unit 312 setting a threshold value of a predetermined power level, and a delay wave larger than the threshold value exists in the delay time exceeding the GI length. Judgment by whether or not.

  FIG. 12 is a diagram for explaining a method for determining whether or not there is a long delay wave exceeding the GI length in the threshold value. FIG. 12A is a diagram showing an impulse response when the power level of the long delay wave exceeding the GI length exceeds the threshold value. Here, the vertical axis is the power level, and the horizontal axis is time. An impulse response w10 exceeding the previously arrived threshold and an impulse response w11 exceeding the subsequently arrived threshold are shown. The impulse response w11 is delayed by a time exceeding the GI length from the leading impulse response of the impulse response w10 exceeding the previously arrived threshold. The power level of the impulse response at the head of the impulse response w11 is larger than the threshold by β.

  In FIG. 12A, when the impulse response is calculated by the propagation path estimation unit 311, the signal level of the impulse response w11 of the delayed wave that arrives in the section exceeding the GI length is equal to or higher than the threshold value. It is determined that there is a delay in the delay time exceeding the GI length.

  FIG. 12B is a diagram showing an impulse response when the power level of the long delay wave exceeding the GI length is smaller than the threshold value. Here, the vertical axis is the power level, and the horizontal axis is time. An impulse response w12 exceeding the previously arrived threshold and an impulse response w13 exceeding the subsequently arrived threshold are shown. The impulse response w13 is delayed by a time exceeding the GI length from the leading impulse response of the impulse response w12 exceeding the previously arrived threshold. The power level of all impulse responses of the impulse response w13 is smaller than the threshold value.

  In FIG. 12B, when the impulse response is calculated by the propagation path estimation unit 311, the signal level of the impulse response w13 of the delayed wave that arrives in the section exceeding the GI length is equal to or lower than the threshold value. It is determined that there is no delay time exceeding the GI length.

  (3) (i) When there is a data error in the determination result by the error detection unit 310 and (ii) and the quality determination unit 312 determines that a long delay wave exceeding the GI length exists, the control signal generation unit 313 The relay station apparatus 200 is notified of a signal to stop amplification (relay apparatus control signal) (step T104 in FIG. 2).

  The relay device control signal is notified by the relay station device 200 assigning and transmitting it to one of the uplink resource elements to be transmitted to the mobile station device 300 or the relay station device 200. For example, when the mobile station apparatus transmits a signal to the relay station apparatus 200 or the mobile station apparatus 300 in the frame format of FIG. 9, the resource element (white portion) mapping the data modulation symbol or the control symbol is mapped. Can be mapped to existing resource elements (grid fills).

  (4) When the relay station device 200 receives the relay device control signal, the amplification unit 203 included in the relay station device 200 stops amplification. For example, the relay station device 200 turns off the power of the amplification unit 203. Alternatively, the amplifying unit 203 reduces the bias current. Or the relay station apparatus 200 stops those operations by turning off the power of the transmission system (filter unit 204 or transmission unit 205) of the relay station apparatus 200. As a result, the transmission power level of the data signal transmitted by the relay station device 200 decreases.

  Thereby, when the relay station apparatus 200 is amplifying the signal, the mobile station apparatus 300 receives a signal exceeding the threshold value shown in the impulse response w11 of FIG. 12A as an example. On the other hand, when relay station apparatus 200 stops signal amplification, mobile station apparatus 300 receives a signal smaller than the threshold value shown in impulse response w13 in FIG. 12B as an example. Therefore, the signal level of the delayed wave exceeding the GI length can be reduced, and the ISI and ICI resulting therefrom can be reduced. As a result, characteristic deterioration can be avoided.

  (5) Alternatively, in the relay station device 300, the amplification unit 203 included in the relay station device 300 lowers the amplification factor. At that time, the mobile station apparatus 300 transmits to the relay station apparatus 200 a relay apparatus control signal having a signal indicating the amplification factor to be set instead of the signal to stop amplification. For example, when the mobile station device 300 calculates the impulse response shown in FIG. 12A, the mobile station device 300 notifies the difference β between the signal level of the delayed wave exceeding the GI length and the threshold value.

The signal indicating the amplification factor may be a value of the amplification factor itself to be set or an index indicating the amplification factor in the amplification factor setting table created in advance.
As a result, similarly to the case where the amplification of the relay station device 200 is stopped, the signal level of the delayed wave exceeding the GI length can be reduced, and the resulting ISI and ICI can be reduced. It can be avoided.

[effect]
In the communication system according to the first embodiment of the present invention, the mobile station apparatus controls the amplification factor of the relay station apparatus in accordance with the reception path of the received signal, so that the ISI caused by the delayed wave exceeding the GI length. , Characteristic deterioration due to ICI can be suppressed. As a result, it is possible to eliminate the restriction on the arrangement position of the relay station device.

<Modification>
In the present embodiment, the example in which the relay station device 200 decreases the amplification factor has been described. However, the present invention is not limited to this, and the relay station device 200 may increase the amplification factor based on the received control signal. Further, relay station apparatus 200 may start or stop amplification based on the received control signal. A specific example in which the relay station apparatus 200 increases the amplification factor will be described below.
In the case of FIG. 1, an example is shown in which the mobile station device 300 transmits a control signal for decreasing the amplification factor, and after a predetermined time has elapsed, the mobile station device 300 transmits a control signal for increasing the amplification factor. .

  First, when the mobile station device 300 receives equivalent signal power from both the base station device 100 and the relay station device 200 (routes r1 and r3), the mobile station device 300 decodes the received signal. Assume that a data error is detected and it is further determined that a signal longer than the GI length is received from the propagation path estimation result. In that case, the mobile station apparatus 300 transmits a control signal for canceling the amplification factor to the relay station apparatus 200.

  Then, relay station apparatus 200 stops amplification in accordance with the control signal transmitted from mobile station apparatus 300, so that mobile station apparatus 300 receives a signal from only base station apparatus 100 (route r1). Thereby, the relay station apparatus 200 can suppress the generation of a delayed wave exceeding the GI length due to reception from both.

Next, when the mobile station apparatus 300 receives a signal only from the base station apparatus 100, if a data error is detected as a result of decoding the received signal, the mobile station apparatus 300 200 transmits a control signal for amplification.
Then, relay station apparatus 200 amplifies the received signal and retransmits it in accordance with the control signal transmitted from mobile station apparatus 300 for amplification. In that case, the mobile station apparatus 300 receives a signal from only the relay station apparatus 200 (route r3). Thereby, even when the signal level of the signal directly received from the base station apparatus 100 has decreased, the mobile station apparatus 300 can maintain good communication.

<Second Embodiment>
Subsequently, a second embodiment of the present invention will be described.
[Communications system]
The second embodiment of the present invention is a case where there are a plurality of mobile station apparatuses connected to the base station apparatus.
FIG. 13 is a diagram showing a communication system according to the second embodiment of the present invention. The communication system includes a base station apparatus (transmission apparatus) 100b, a relay station apparatus (relay apparatus) 200b, a mobile station apparatus (reception apparatus) 300b, and a mobile station apparatus 400. Elements common to those in FIG. 1 are denoted by the same reference numerals, and a specific description thereof is omitted.

  r1 is a path through which a radio signal transmitted from the base station apparatus 100b directly reaches the mobile station apparatus 300b, r2 is a path through which a radio signal transmitted from the base station apparatus 100b reaches the relay station apparatus 200b, and r3 is a path from the base station apparatus 100b. The route between the relay station device 200b and the mobile station device 300b when the transmitted radio signal reaches the mobile station device 300b via the relay station device 200b, and r5 is the radio signal transmitted by the base station device 100b. This is a path between the relay station device 200b and the mobile station device 400 when the mobile station device 400 is reached via. R4 is a path when the mobile station device 300b transmits a control signal (relay device control signal) for controlling the relay station device 200b.

  Base station apparatus 100b transmits a radio signal of information data and control data to mobile station apparatus 300b and mobile station apparatus 400 by radio signals (RF signals). The relay station apparatus 200b amplifies and filters the radio signal received from the base station apparatus 100b, and then outputs it.

  FIG. 14 is a diagram illustrating a radio signal of information data transmitted by the base station device 100b. FIG. 14 shows an example of OFDM modulation, in which data modulation symbols of information data to be transmitted to mobile station apparatus 300b are assigned to subcarriers 1 to 8 and information data to be transmitted to mobile station apparatus 400 is transmitted. Data modulation symbols are assigned to subcarrier 9 to subcarrier 16.

  When the mobile station apparatus 300b or the mobile station apparatus 400 receives the signal shown in FIG. 14, the mobile station apparatus 300b or the mobile station apparatus 400 performs a demodulation process such as FFT on the OFDM modulation, and then processes the subcarrier signal to which the information data addressed thereto is assigned. The information data addressed to itself is acquired by performing processing such as decryption.

  FIG. 15 is a sequence diagram illustrating exchange of signals among the base station apparatus 100b, the relay station apparatus 200b, and the mobile station apparatus 300b in the second embodiment. In FIG. 15, the processing of step T104 and step T105 in FIG. 2 is changed to the processing of step T304 and step T305, respectively. Hereinafter, different processes will be described.

  Based on the reception quality, mobile station apparatus 300b transmits a control signal (relay apparatus control signal) for the amplification factor and the band for controlling the amplification factor to relay station apparatus 200b (step T304). The relay device control signal may be a signal notifying that the amplification is stopped (amplification factor is zero). The relay station apparatus 200b changes the amplification factor for the designated frequency band based on the relay apparatus control signal (step T305).

  In FIG. 13, mobile station apparatus 400 receives the information data addressed to itself transmitted from base station apparatus 100b only from relay station apparatus 200b, so that mobile station apparatus 400 has an amplification factor with respect to relay station apparatus 200b. Do not send control signals for.

[Operation of mobile station device]
The operation of the mobile station device 300b is the same as the flowchart shown in FIG. However, the present embodiment is different in that the relay apparatus control signal transmitted from the mobile station apparatus 300b in step S107 in FIG. 3 is a control signal related to the setting of the amplification factor and its band. For example, in the case of FIG. 14, the mobile station device 300b notifies that the amplification is stopped for the subcarriers 1 to 8 that are bands to which the information data addressed thereto is allocated.

[Operation of relay station equipment]
FIG. 16 is a flowchart showing the operation of relay station apparatus 200b. The flowchart of FIG. 16 is obtained by changing the processing of step S205 and step S206 in the flowchart of FIG. 7 to processing of step S405 and step S406, respectively. In addition, the same code | symbol is attached | subjected to the process which is common in FIG. Hereinafter, mainly different processes will be described.

When the relay station apparatus 200b receives the radio signal of the information data (step S201 YES), the relay station apparatus 200b amplifies the signal based on the currently set amplification factor, filters it (step S202), and transmits the signal (step S203). ).
On the other hand, when the radio signal of the information data is not received (NO in step S201), the relay station device 200b determines whether or not the relay device control signal supplied from the mobile station device 300b has been received (step S204).

  When the relay station control signal is not received (NO in step S204), the relay station apparatus 200b returns to the process of step S201. On the other hand, when the relay station device 200b receives the relay device control signal from the mobile station device 300b (YES in S204), the relay station device 200b performs detection processing on the control signal, and sets the amplification factor and controls the frequency band. Control data is acquired (step S405). Then, according to the instruction of the control data, relay station apparatus 200b changes the setting of the amplification factor of the amplification unit in that band (step S406) and waits for the next signal to arrive. Above, the process of this flowchart is complete | finished.

  FIG. 17 is a diagram illustrating a radio signal of information data retransmitted by relay station apparatus 200b after relay station apparatus 200b receives a relay apparatus control signal from mobile station apparatus 300b. The vertical axis is the power level, and the horizontal axis is the frequency. When the mobile station apparatus 300b notifies that the amplification is stopped for the band (subcarrier 1 to subcarrier 8) to which the information data addressed to itself is allocated, the relay station apparatus 200b displays the base station apparatus shown in FIG. After amplifying the input of the information data radio signal supplied from 100b, the band for the mobile station device 300b is filtered to reduce the power level. Thereby, the relay station device 200b supplies the radio signal of the information data shown in FIG. 17 to the mobile station device 300b and the mobile station device 400.

[Configuration of base station apparatus]
FIG. 18 is a functional block diagram showing a configuration example of the base station apparatus 100b according to the second embodiment of the present invention. FIG. 18 illustrates a case where the radio signal transmitted by the base station apparatus is an OFDM signal.

  18, the base station apparatus 100b connects the symbol generation unit 112 of the base station apparatus 100 in FIG. 8 to the symbol generation unit 112-u (u is an integer from 1 to U, U is the base station apparatus 100b. This is realized by replacing the resource mapping unit 106 with the resource mapping unit 406 in the number of mobile station apparatuses). In addition, the same code | symbol is attached | subjected to the element which is common in FIG. 8, and the specific description is abbreviate | omitted. Hereinafter, different parts will be mainly described.

Each symbol generator 112-u generates a data modulation symbol addressed to mobile station apparatus 300 or mobile station 400. For example, in the case of FIG. 13, u = 2, the symbol generation unit 112-1 generates a data modulation symbol addressed to the mobile station apparatus 300, and the symbol generation unit 112-2 generates a data modulation symbol addressed to the mobile station apparatus 400 To do. Each symbol generation unit 112-u supplies the data modulation symbol to the resource resource mapping unit 406.
Resource resource mapping section 406 subcarriers the data modulation symbols supplied from symbol generation section 112-u, the control symbols supplied from control signal generation section 110, and the pilot symbols supplied from pilot signal generation section 111. To map. The resource resource mapping unit 406 supplies the mapped signal to the IFFT unit 107.

  Then, IFFT section 107 performs IFFT processing on the mapped signal supplied from resource mapping section 406. The GI insertion unit 108 inserts a GI into the IFFT-processed signal, and the transmission unit 109 transmits the signal with the GI inserted from the antenna 101.

[Configuration of relay station device]
FIG. 19 is a functional block diagram showing a configuration example of the relay station apparatus 200b according to the second embodiment of the present invention. Relay station apparatus 200b is realized by replacing amplification section 203 with amplification section 503, filter section 204 with filter section 504, and control signal detection section 207 with control signal detection section 507 in relay station apparatus 200 in FIG. ing. In addition, the same code | symbol is attached | subjected to the element which is common in FIG. 10, and the specific description is abbreviate | omitted. Hereinafter, different parts will be mainly described.

  The control signal detection unit 507 performs signal detection processing such as demodulation processing and decoding processing on the received relay device control signal. The control signal detection unit 507 acquires the setting of the amplification factor to be set (or the presence / absence of amplification) and the relay device control signal for the predetermined frequency band by the signal detection process, and sends the control signal for the relay unit to the amplification unit 503 and the filter unit 504. Supply.

  The amplification unit 503 sets the amplification factor based on the relay device control signal supplied from the control signal detection unit 507. Then, according to the set amplification factor, the wireless signal of the information data supplied from the receiving unit 202 is amplified. The amplifying unit 503 supplies the radio signal of the amplified information data to the filter unit 504.

  Based on the relay device control signal supplied from the control signal detection unit 507, the filter unit 504 sets the band assigned to the signal to be amplified (hereinafter referred to as a pass band). The filter unit 504 performs a filtering process to limit the band for a certain period of time on the radio signal of the amplified information data supplied from the amplification unit 503. Specifically, the filter unit 504 sets the frequency bandwidth other than the band to which the mobile station device 300b is assigned as the pass band. The filter unit 504 supplies the filtered signal to the transmission unit 205.

[Configuration of mobile station device]
FIG. 20 is a functional block diagram showing a configuration example of the mobile station apparatus 300b according to the second embodiment of the present invention. The mobile station device 300b can be realized by replacing the control signal generation unit 313 with the control signal generation unit 613 in the mobile station device 300 of FIG. In addition, the same code | symbol is attached | subjected to the element which is common in FIG. 11, and the specific description is abbreviate | omitted. Hereinafter, different parts will be mainly described.

The control signal generation unit 613 determines a band for setting the amplification factor based on the determination result (information indicating whether the GI length is exceeded or there is a delayed wave or reception quality information) supplied from the quality determination unit 312. And the amplification factor in the band is calculated. Then, the control signal generation unit 613 generates a relay device control signal including an amplification factor command for the band for the relay station device 200b.
The control signal generation unit 613 receives an error detection result from the error detection unit 310 supplied from the quality determination unit 312 and generates an ACK signal or a NACK signal. The control signal generation unit 613 supplies the generated signal to the transmission unit 314.

Subsequently, an example of a method for determining the amplification factor and the band will be described.
FIG. 21 is a diagram illustrating user assignment when a base station apparatus transmits data to a mobile station apparatus or a relay station apparatus in a downlink that transmits OFDMA (Orthogonal Frequency Division Multiple Access).

  In the same figure, a subframe comprising three resource elements on the frequency axis and 14 resource elements on the time axis is shown, and the first three resource elements on the time axis have a control signal (for example, LTE (Long Term Evolution: 3 PDCCH (Physical Control Channel) in the 9G radio access technology) is assigned, and the data signal of each user is assigned to the 9 resource elements after the PDCCH (Physical Control Channel).

  In the frame shown in FIG. 21, both the data signal addressed to the mobile station device 300b and the data signal addressed to the mobile station device 400 are received for a predetermined time in the first subframe and the fifth subframe (right hatched portion). Assigned at every interval. In addition, a data signal addressed to the mobile station apparatus 300b is assigned to the left oblique line part, and a data signal addressed to the mobile station apparatus 400 is assigned to the grid-like painted part.

  The base station apparatus 100b transmits a data signal using a transmission frame including 10 subframes to the mobile station apparatus 300b or the relay station apparatus 200b. The subframe is composed of 14 OFDM symbols. Each user is assigned to a unit (hereinafter referred to as a resource element) composed of a predetermined subcarrier and a predetermined OFDM symbol.

In FIG. 21, mobile station apparatus 300b and mobile station apparatus 400 are allocated according to a certain rule (for example, semi-persistent scheduling in LTE), and the user allocation is performed until the scheduling mode ends. Similar user assignments are made.
Here, the scheduling mode continues over the frame. Further, the data signal allocation to the mobile station device 300b is notified by the control signal (the signal of the painted portion) allocated to the resource element (0, 2).

Hereinafter, an example of the processing flow for changing the amplification factor will be described.
(1) First, the mobile station device 300b acquires a data signal allocation position addressed to the own user in the frame by a control signal allocated to the resource element (0, 2). Then, the data signal of the user of subframe 0 is demodulated, decoded, and error-detected, and (i) whether there is a data error, (ii) and there is a long delay wave exceeding the GI length. Whether or not is determined as described above.

  (2) When the mobile station apparatus 300b determines that (i) there is a data error and (ii) a long delay wave exceeding the GI length exists in the determination result, the mobile station apparatus 300b stops the amplification to the relay station apparatus 200b. A signal (relay device control signal) indicating the effect and its band and timing is transmitted.

  In FIG. 21, mobile station apparatus 300b transmits the band of the resource element indicated by the left hatched portion and its timing to relay station apparatus 200b. That is, the fact that the data signal addressed to mobile station apparatus 300b is assigned to frequency band 0 of subframe 0 and subframe 5 is transmitted to relay station apparatus 200b. The notification of the relay device control signal is performed by the mobile station device 300b assigning and transmitting to one of the uplink resource elements to be transmitted to the relay station device 200b.

  (3) When the relay station apparatus 200b receives the relay apparatus control signal, the relay station apparatus 200b stops amplification in the band and timing to which the notified resource element is allocated in and after subframe 1. That is, in subframe 5, the amplification of the band (hatched portion) to which mobile station apparatus 300b is allocated is stopped in synchronization with the timing of the fourth resource element. The relay station apparatus 200b cancels the amplification of the signal band, for example, by changing the pass band of the filter included in the relay station apparatus 200b.

  The amplification of the signal band can be continued in the next frame. That is, in the next frame, relay station apparatus 200b cancels amplification of the signal band for subframe 0 and subframe 5.

  The relay station apparatus 200b ends the cancellation of the amplification of the signal band by releasing the scheduling mode. As a result, when a plurality of mobile station apparatuses are assigned, relay station apparatus 200b suffers from the adverse effects of receiving both the signal directly coming from base station apparatus 100b and the signal from relay station apparatus 200b. Amplification can be stopped only for the existing mobile station apparatus. That is, the adverse effects can be eliminated without affecting the mobile station apparatus that is benefiting from receiving the signal via the relay station apparatus 200b.

[effect]
In the communication system according to the second embodiment of the present invention, the mobile station apparatus delays exceeding the GI length by controlling the amplification factor setting and the bandwidth of the relay station apparatus according to the reception quality of the received signal. It is possible to suppress characteristic deterioration due to ISI and ICI caused by waves. Thereby, when a plurality of mobile station apparatuses are connected to the base station apparatus, the amplification factor can be set according to the propagation path condition of each mobile station apparatus. Thereby, even if the arrangement position of the relay station apparatus is determined in advance, the relay station apparatus can perform stable communication with each mobile station apparatus.

<Third Embodiment>
Subsequently, a third embodiment of the present invention will be described.
[Communications system]
FIG. 22 is a diagram showing a communication system according to the third embodiment of the present invention. The communication system in the figure includes a base station device (reception device) 100c, a relay station device (relay device) 200c, and a mobile station device (transmission device) 300c. The third embodiment of the present invention is a case where the method of the first embodiment is applied to the uplink of the communication system.

  r21 is a path through which a radio signal transmitted from the mobile station apparatus 300c directly reaches the base station apparatus 100c, r22 is a path through which a radio signal transmitted from the mobile station apparatus 300c reaches the relay station apparatus 200c, and r23 is a path through which the mobile station apparatus 300 is transmitted. This is a path between the relay station device 200c and the base station device 100c when the transmitted radio signal reaches the base station device 100c via the relay station device 200c. R24 is a path when the base station apparatus 100c transmits a control signal (relay apparatus control signal) for controlling the relay station apparatus 200c.

  The mobile station device 300c transmits a radio signal (RF signal) including information data and control data to the base station device 100c and the relay station device 200c. The relay station device 200c amplifies the radio signal supplied from the mobile station device 300c, and filters (filters) a predetermined frequency band. Then, relay station apparatus 200c supplies the filtered signal to base station apparatus 100c.

  The base station device 100c receives a radio signal including information data and control data transmitted by the mobile station device 300c from the route r21, the route r23, or both. Then, the base station device 100c generates a relay device control signal according to the reception status. The base station device 100c controls the amplification factor of the amplification unit in the relay station device 200c by transmitting the relay device control signal to the relay station device 200c.

  In FIG. 22, a wireless line is used as the path r23 between the base station apparatus 100c and the relay station apparatus 200c and the path r24 between the base station apparatus 100c and the relay station apparatus 200c. A wired line may be used.

  FIG. 23 is a sequence diagram illustrating signal communication among the base station device 100c, the relay station device 200c, and the mobile station device 300c in the third embodiment. In FIG. 23, the mobile station device 300c is linked between the mobile station device 300c and the base station device 100c by control data (for example, a random access channel) transmitted and received between the mobile station device 300c and the base station device 100c. A description will be given assuming that the connection is completed.

  The mobile station device 300c transmits a radio signal of information data to the base station device 100c, and the base station device 100c directly (route r21) from the mobile station device 300c and via the relay station device 200c (route r22 and route r23). The wireless signal of the information data is received from both of them (step T501). The base station apparatus performs signal detection on the information data radio signal (step T502), and transmits a signal (ACK signal / NACK signal) indicating whether or not the information data radio signal has been correctly received to the mobile station apparatus 300c. (Step T503).

In addition, when the base station apparatus 100c cannot correctly receive the information data radio signal, the base station apparatus 100c detects the signal from the information data radio signal and uses the propagation path estimation pilot signal inserted in the received data signal. Receive quality is calculated (step T502).
Then, a control signal (relay device control signal) for controlling the amplification factor is transmitted to the relay station device based on the reception quality (route r24, step T504). Here, the relay device control signal may be a signal notifying that the amplification is stopped (amplification factor is zero).

The relay station device 200c changes the amplification factor based on the relay device control signal transmitted from the base station device 100c (step T505).
Then, when mobile station apparatus 300c transmits a radio signal of information data again to relay station apparatus 200c, base station apparatus 100c performs relay station apparatus 200c directly subjected to signal amplification from mobile station apparatus 300c and different from step T501. The via signal is received (step T506).

  When the relay device control signal is a signal notifying that the amplification of the relay station device is to be stopped, the base station device receives only a direct signal from the mobile station device. Here, the relay device control signal may be a signal for lowering the amplification factor for a certain period or a signal for stopping amplification for a certain period.

  Note that the flowchart of FIG. 3 is applied to the operation of the base station apparatus 100c in step S502. Further, the operation of the relay station device 200c is applied mutatis mutandis to the flowchart of FIG. The base station apparatus 100c has the configuration of FIG. 11, the relay station apparatus 200c has the configuration of FIG. 10, and the mobile station apparatus 300c has the configuration of FIG.

  In the present embodiment, the base station device 100c has been described as the case where the control signal for setting the amplification factor is transmitted to the relay station device 200c as the relay device control signal. It may be a control signal for setting the amplification factor and its band. In that case, the base station apparatus 100c has the same configuration as in FIG. 20, and the relay station apparatus 200c has the same configuration as the relay station apparatus 500 in FIG.

[effect]
In the communication system according to the third embodiment of the present invention, the base station apparatus controls the setting of the amplification factor of the relay station apparatus and / or the band thereof according to the reception path of the received signal, thereby increasing the GI length. It is possible to suppress deterioration of characteristics due to ISI and ICI due to a delayed wave exceeding. Thereby, even if the arrangement position of the relay station apparatus is determined in advance, the relay station apparatus can perform stable communication with each mobile station apparatus.

  As described above, in relay transmission, the maximum speed (cell throughput) at which one base station apparatus can communicate even in an environment having a reception apparatus that receives a signal directly coming from a transmission apparatus and a signal arriving via the relay apparatus. Can be improved.

  The program for realizing the function of each unit described in the embodiment of the present invention is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. You may perform the process of each part. The “computer system” here includes an OS and hardware such as peripheral devices.

Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system.

  Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the above-described functions, or may be a program that can realize the above-described functions in combination with a program already recorded in a computer system.

  Also, the functions of all or part of the transmission apparatus in FIGS. 8 and 18, all or part of the relay apparatus in FIGS. 10 and 19, and all or part of the reception apparatus in FIGS. 11 and 20 are integrated. It may be realized by concentrating on a circuit. Each functional block of the transmission device, the relay device, and the reception device may be individually chipped, or a part or all of them may be integrated into a chip.

  Further, a chip control circuit that controls each functional block of the transmission device, the relay device, and the reception device that are made into chips may be integrated. The method of designating and integrating circuits is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. In addition, when an integrated circuit technology that replaces LSI appears due to progress in semiconductor technology, an integrated circuit based on the technology can also be used.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design etc. of the range which does not deviate from the summary of this invention are included.

  The present invention can be used in the field of mobile communication or fixed communication using radio.

100 Base station device (transmitting device)
100b Base station apparatus (transmission apparatus)
100c Base station device (receiving device)
DESCRIPTION OF SYMBOLS 101 Reception antenna part 102 Error detection encoding part 103 Error correction encoding part 104 Interleaving part 105 Modulation part 106 Resource mapping part 107 IFFT (Inverse Fast Fourier Transform) part 108 GI insertion part 109 Transmission part 110 Control signal generation part 111 Pilot signal generation part 112 Symbol generator 200 Relay station device (relay device)
200b Relay station device (relay device)
200c Relay station device (relay device)
201 reception antenna unit 202 reception unit 203 amplification unit 204 filter unit 205 transmission unit 206 transmission antenna unit 207 control signal detection unit 300 mobile station apparatus (reception apparatus)
300b Mobile station device (receiving device)
300c Mobile station device (transmitting device)
301 reception antenna unit 302 reception unit 303 GI removal unit 304 FFT unit 305 propagation path compensation unit 306 resource demapping unit 307 demodulation unit 308 deinterleave unit 309 decoding unit 310 error detection unit 311 propagation path estimation unit 312 quality judgment unit 313 control signal Generation unit 314 Transmission unit 315 Transmission antenna unit 400 Mobile station apparatus

Claims (15)

A transmission device for transmitting a data signal;
A relay device that receives the data signal, amplifies the data signal, and transmits the amplified signal;
A receiving device for receiving signals from the transmitting device and the relay device;
With
The receiving device transmits a control signal instructing the amplification factor or the presence or absence of amplification to the relay device,
The relay device changes an amplification factor or starts or stops amplification based on the control signal.   2. The communication system according to claim 1, wherein the control signal includes information indicating a frequency band for setting the amplification factor or setting the presence / absence of amplification to the relay device. The communication system according to claim 2, wherein the control signal includes information instructing to change an amplification factor of a frequency band assigned to a data signal transmitted to the receiving device.   The communication system according to claim 2, wherein the relay station device sets a frequency band through which the data signal passes based on the control signal. The transmitting device is a base station device;
The communication system according to any one of claims 1 to 4, wherein the reception device is a mobile station device. The communication system includes a plurality of the receiving devices,
The communication system according to any one of claims 1 to 4, wherein the relay device controls an amplification factor for each individual receiving device. The transmitting device is a mobile station device;
The communication system according to claim 1, wherein the relay device is a base station device.   The said receiving apparatus transmits the said control signal to the said relay station apparatus, when the delay wave over a predetermined period is received, The said control signal is any one of Claim 1-7 Communications system.   The communication system according to claim 8, wherein the control signal includes information instructing to decrease the amplification factor.   The communication system according to claim 8, wherein the control signal includes information instructing to stop the amplification. A receiver for receiving a data signal;
A quality determination unit for determining whether the data signal is a signal of a delayed wave exceeding a predetermined period;
A control signal generation unit that generates a control signal that indicates the amplification factor of the data signal or the presence or absence of amplification based on the determination of the quality determination unit;
A receiving apparatus comprising: A receiver for receiving the data signal and the control signal;
An amplifier for amplifying the data signal;
A transmission unit for transmitting the signal amplified by the amplification unit;
A control signal detector that detects information indicating the amplification factor or the presence or absence of amplification from the control signal;
With
The amplifying unit changes an amplification factor or starts or stops amplification based on the information. In a communication method in a communication system having a transmission device, a relay device, and a reception device,
A transmission step of transmitting a data signal;
A relay step in which the relay device receives the data signal, amplifies the data signal, and transmits the amplified signal;
A receiving step in which the receiving device receives the amplified signal;
A transmitting step in which the receiving device transmits a control signal indicating an amplification factor or presence / absence of amplification to the relay device;
An amplification change step in which the relay device changes an amplification factor based on the control signal, or starts or stops amplification, and
A communication method characterized by comprising: A quality determination step for determining whether or not the received data signal is a signal due to a delayed wave exceeding a predetermined period; and
A control signal generation step for generating a control signal instructing the amplification factor of the data signal or the presence or absence of amplification based on the determination in the quality determination step by the reception device;
A receiving method comprising: An amplification step in which the relay device amplifies the received data signal;
A transmission step in which the relay device transmits the signal amplified in the amplification step;
A control signal detection step for detecting information indicating the amplification factor or the presence or absence of amplification from the control signal received by the relay device;
An amplification change step in which the relay device changes the amplification factor based on the information, or starts or stops amplification, and
A relay method characterized by comprising:

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