WO2013161054A1 - Station de base sans fil, terminal sans fil, système de communication sans fil et procédé de commande de communication - Google Patents

Station de base sans fil, terminal sans fil, système de communication sans fil et procédé de commande de communication Download PDF

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Publication number
WO2013161054A1
WO2013161054A1 PCT/JP2012/061362 JP2012061362W WO2013161054A1 WO 2013161054 A1 WO2013161054 A1 WO 2013161054A1 JP 2012061362 W JP2012061362 W JP 2012061362W WO 2013161054 A1 WO2013161054 A1 WO 2013161054A1
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Prior art keywords
radio
base station
wireless
area
station
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Ceased
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English (en)
Japanese (ja)
Inventor
耕太郎 椎▲崎▼
大介 実川
伊藤　章
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Fujitsu Ltd
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Fujitsu Ltd
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Priority to PCT/JP2012/061362 priority Critical patent/WO2013161054A1/fr
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. Transmission Power Control [TPC] or power classes
    • H04W52/04—Transmission power control [TPC]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/08—Access point devices
    • H04W88/085—Access point devices with remote components

Definitions

  • the present invention relates to a radio base station, a radio terminal, a radio communication system, and a communication control method.
  • CoMP scenario 4 remote radio heads (RRH, overhanging stations) 200-1 and 200-2 are arranged in a radio area 400 of eNodeB (eNB, radio base station) 100, as illustrated in FIG. A system configuration is assumed in which the eNB 100 and each of the RRHs 200-1 and 200-2 are connected by a high-speed interface such as an optical fiber.
  • eNodeB eNodeB
  • UEs 300-1 to 300-7 are located in the radio area 400 of the eNB 100, and UEs 300-3 and 300-4 are located in the radio area 500-1 of the RRH 200-1. . Furthermore, UEs 300-5 to 300-7 are located in the radio area 500-2 of the RRH 200-2. Also, in CoMP scenario 4, by sharing the cell ID between the eNB 100 and each of the RRHs 200-1 and 200-2, load reduction of mobility control, sharing of cell-specific resources, and the like are achieved.
  • each of the UEs 300-1 to 300-7 transmits a Sounding Reference Symbol (SRS) as an example of a known signal for estimating the quality of an uplink radio channel to the eNB 100 and the RRHs 200-1 and 200-2.
  • SRS Sounding Reference Symbol
  • the uplink transmission power control when each UE 300-1 to 300-7 transmits the SRS is offset to the Transmission Power Control (TPC) of the Physical Uplink Shared Channel (PUSCH). It is specified to be performed according to the following control equation (1) having the added shape.
  • Is a subframe Is the transmission power of SRS, Is the maximum transmit power, Is an offset value from the transmission power of PUSCH, Is the number of PUSCH allocation resources, Is the PUSCH received power target value, Is the path loss coefficient, Is a propagation loss (path loss) between the UE 300-1 to 300-7 and the serving base station, Represents the power adjustment coefficient of PUSCH, respectively.
  • the above control equation (1) is intended to compensate for the path loss of the serving cell.
  • the following control expression (2) is proposed in 3GPP contribution “R1-113328” and the like.
  • the above control equation (2) is intended to receive the SRS in the entire CoMP set, and has the advantage that the reception quality of UpLink (UL, uplink) can be obtained by more eNBs 100, RRHs 200-1, 200-2. There is.
  • the UEs 300-1 to 300-7 are allocated radio resources for transmitting SRS from the eNB 100, and transmit SRSs using the allocated radio resources.
  • each UE 300-1 to 300-7 is assigned radio resources that can be identified by different base sequences, cyclic shifts (CS), and comb teeth, and applies frequency hopping to the assigned radio resources.
  • SRS is transmitted.
  • radio resources defined by a combination of frequency and time (timing) are allocated to each UE.
  • radio resources # 1 to # 7 represent radio resources allocated to the UEs 300-1 to 300-7, respectively.
  • CoMP scenario 4 since a common cell ID is used by eNB 100 and each RRH 200-1 and 200-2, there is one base sequence.
  • the eNB 100 can only identify SRSs from 16 UEs.
  • CoMP scenario 4 when the number of UEs increases, even when considering the difference in SRS transmission timing, the case of transmitting SRS in the same band and the same timing Can happen enough.
  • SRS interference may occur.
  • a plurality of UEs transmit SRS using the same radio resource, or when a plurality of UEs transmit SRS using radio resources at least partially overlapping each other, an SRS collision occurs and interference occurs. May occur.
  • an object of the present invention is to suppress interference of known signals.
  • the present invention is not limited to the above-described objects, and is an operation and effect derived from each configuration shown in the embodiment for carrying out the invention described below, and also exhibits an operation and effect that cannot be obtained by conventional techniques. It can be positioned as one of the purposes.
  • the other signal so that a known signal transmitted by a wireless terminal located in a wireless area of another wireless base station different from the own station among the plurality of wireless terminals is received by a wireless base station other than the own station.
  • a processing unit that controls transmission power of a wireless terminal located in the wireless area of the wireless base station, and at least a known signal transmitted by a wireless terminal located in the wireless area of the own station among the plurality of wireless terminals It is possible to use a radio base station that includes a receiving unit.
  • radio resources at least partially overlapping each other are allocated to a plurality of radio terminals including the own station.
  • radio resources that are at least partially overlapping among a plurality of radio resources used when transmitting a known signal are allocated to a plurality of radio terminals.
  • a known signal transmitted by a wireless terminal located in a wireless area of another wireless base station different from the own station among the plurality of wireless terminals is received by a wireless base station other than the own station.
  • a radio base station that controls transmission power of a radio terminal located in the radio area of the other radio base station, and a transmission power that is located in the radio area of the other radio base station and controlled by the radio base station It is possible to use a wireless communication system that includes a wireless terminal that transmits the known signal using a wireless communication device.
  • a fourth plan for example, in a radio base station, radio resources at least partially overlapping each other among a plurality of radio resources used when transmitting a known signal to a plurality of radio terminals Among the plurality of wireless terminals, a known signal transmitted by a wireless terminal located in a wireless area of another wireless base station different from the own station is transmitted by a wireless base station other than the own station.
  • the transmission power of a radio terminal located in the radio area of the other radio base station is controlled to be received, and the controlled transmission power is controlled in a radio terminal located in the radio area of the other radio base station.
  • a communication control method can be used in which the known signal is transmitted using the.
  • FIG. (A) And (B) is a figure which shows an example of the transmission format of an instruction
  • (A) And (B) is a figure which shows an example of the transmission format of a notification signal. It is a figure which shows an example of operation
  • FIG. 3 is a diagram illustrating an example of the configuration of a radio communication system according to one embodiment.
  • the radio communication system 6 shown in FIG. 3 illustratively includes an eNB 1 that is an example of a radio base station, extended stations (RRH) 2-1 and 2-2, and a plurality of user apparatuses (UE) 3-1 to 3-7.
  • eNB 1 that is an example of a radio base station
  • RRH extended stations
  • UE user apparatuses
  • RRHs 2-1 and 2-2 when RRHs 2-1 and 2-2 are not distinguished, they are simply expressed as RRH2, and when UEs 3-1 to 3-7 are not distinguished, they are simply expressed as UE3.
  • the numbers of RRH2 and UE3 are not limited to the numbers illustrated in FIG.
  • the eNB 1 provides a radio area 4 such as a cell or a sector, and can perform radio communication with the UEs 3-1 to 3-7 located in the radio area 4.
  • the RRH 2-1 provides a radio area 5-1, and can perform radio communication with the UEs 3-3 and 3-4 located in the radio area 5-1.
  • the RRH 2-2 provides a radio area 5-2 and can perform radio communication with UEs 3-5 to 3-7 located in the radio area 5-2.
  • the eNB 1 and the RRHs 2-1 and 2-2 are connected by a high-speed interface such as an optical fiber and can communicate with each other.
  • a high-speed interface such as an optical fiber
  • the interface between the eNB 1 and the RRHs 2-1 and 2-2 is not limited to an optical fiber, and for example, an X2 interface or a wireless backhaul may be used.
  • CoMP technology can be used.
  • the eNB 1 directly receives a signal transmitted from the UE 3 to the local station 1 and transmits a signal transmitted from the UE 3 to the other station 2 via a high-speed interface such as an optical fiber.
  • a high-speed interface such as an optical fiber.
  • the RRH 2 directly receives a signal transmitted from the UE 3 to the own station 2 and receives a signal transmitted from the UE 3 to the other station 1 via a high-speed interface such as an optical fiber, and combines the received signals. By doing so, uploading of data can be speeded up.
  • each UE 3 receives a signal transmitted from the eNB 1 to the local station 3 and receives a signal transmitted from the RRH 2 to the local station 3.
  • DL downlink
  • each UE 3 is pre-assigned from eNB 1 or RRH 2 radio resources for transmitting a known reference signal (SRS) for estimating the quality of an uplink radio channel, and uses the assigned radio resources for SRS. Send. Note that this SRS is not a target of the synthesis process in CoMP.
  • SRS known reference signal
  • the same radio resource may be allocated to different UEs 3 in duplicate.
  • UE 3-1 and UE 3-7 performs transmission power control according to the following control equation (2)
  • UE 3-7 transmits the SRS to the eNB 1 and the RRH 2-2 using the same radio resource while transmitting the SRS to the eNB 1 using the resource.
  • the eNB 1 may collide with the SRS transmitted from the UE 3-1 and the SRS transmitted from the UE 3-7, and there is a possibility that SRS interference occurs.
  • SRS interference occurs, the eNB 1 cannot appropriately estimate the uplink channel quality and may not be able to perform efficient CoMP. Therefore, in this example, as illustrated in FIG. 4, first, the eNB 1 or the RRH 2 assigns radio resources for SRS transmission to each UE 3, and the same radio resource is duplicated in different UE 3. Detect whether it was assigned or not.
  • step S10 When it detects that the same radio resource is assigned to different UEs 3 (duplication of SRS radio resources) (step S10), eNB1 or RRH2 detects at least one of UEs 3 to which the same radio resource is assigned. Then, switching of transmission power control is instructed (step S11).
  • the UE 3 instructed to switch the transmission power control performs, for example, transmission power control according to the following control equation (1) so that the SRS reaches only the serving cell (step S12), and the SRS is determined based on the determined transmission power. Is transmitted (step S13).
  • step S14 when eNB1 or RRH2 detects that the duplication of SRS radio resources has been resolved (step S14), among UE3s that have been assigned the same radio resource, to UE3 that has instructed step S11. Then, switching of transmission power control is instructed (step S15). UE3 instructed to switch transmission power control performs transmission power control according to the following control equation (2), for example, so that the SRS reaches all reception points in the CoMP set (step S16). The SRS is transmitted with the determined transmission power (step S17).
  • FIG. 5 is a diagram illustrating an example of the configuration of eNB1. Since RRH2 has the same configuration as eNB1, description of the configuration example of RRH2 is omitted.
  • the eNB 1 illustrated in FIG. 5 exemplarily includes an antenna 11, a duplexer 12, a reception unit 13, a channel estimation unit 14, a control signal demodulation / decoding unit 15, a data signal demodulation / decoding unit 16, and a reception quality calculation.
  • a unit 17 and a scheduler 18 are provided.
  • eNB1 illustrated in FIG. 5 exemplarily includes a data signal generation unit 19, a control signal generation unit 20, a reference signal generation unit 21, a data signal encoding modulation unit 22, and a control signal encoding modulation unit 23.
  • an assigning unit 24 and a transmitting unit 25 exemplarily includes a transmitting unit 25.
  • the antenna 11 functions as a reception antenna that receives a radio signal from the UE 3 and also functions as a transmission antenna that transmits a radio signal to the UE 3. That is, the antenna 11 of this example has a configuration in which the reception antenna and the transmission antenna are shared by the duplexer 12. Note that FIG. 5 merely shows an example of the configuration of the eNB 1. For example, when the duplexer 12 is not used, the eNB 1 may have a transmission antenna and a reception antenna individually.
  • the receiving unit 13 extracts a reference signal (SRS), a control signal, and a data signal from uplink radio signals such as PUSCH and Physical-Uplink-Control-Channel (PUCCH) transmitted from the UE 3 received by the antenna 11.
  • SRS reference signal
  • PUCCH Physical-Uplink-Control-Channel
  • the reference signal, control signal, and data signal extracted by the reception unit 13 are output to the channel estimation unit 14, the control signal demodulation / decoding unit 15, and the data signal demodulation / decoding unit 16, respectively.
  • the receiving unit 13 functions as an example of a receiving unit that receives at least a known signal such as SRS transmitted by the wireless terminal 3 located in the wireless area of the local station 1 among the plurality of wireless terminals 3.
  • the channel estimation unit 14 calculates a channel estimation value using the reference signal extracted by the reception unit 13.
  • the channel estimation value calculated by the channel estimation unit 14 is output to the control signal demodulation / decoding unit 15, the data signal demodulation / decoding unit 16, and the reception quality calculation unit 17, respectively.
  • the control signal demodulation / decoding unit 15 performs demodulation processing and decoding processing on the control signal extracted by the reception unit 13 using the channel estimation value calculated by the channel estimation unit 14.
  • the control information obtained by the control signal demodulation / decoding unit 15 is output to the data signal demodulation / decoding unit 16 and the scheduler 18, respectively. Further, ACKnowledgement (ACK) indicating that the decoding result is normal or Negative ACKnowledgement (NACK) indicating that the decoding result is abnormal may be output to the scheduler 18.
  • ACK acknowledgement
  • NACK Negative ACKnowledgement
  • the data signal demodulation / decoding unit 16 performs demodulation processing and decoding processing on the data signal extracted by the reception unit 13 using the channel estimation value calculated by the channel estimation unit 14.
  • the data obtained by the data signal demodulation / decoding unit 16 is output to the scheduler 18. Further, ACK indicating that the decoding result is normal or NACK indicating that the decoding result is abnormal may be output to the scheduler 18.
  • the reception quality calculation unit 17 uses the channel estimation value calculated by the channel estimation unit 14 to calculate reception quality such as a signal-to-interference ratio (SIR). Information regarding the reception quality calculated by the reception quality calculation unit 17 is output to the scheduler 18.
  • the scheduler 18 sends a signal generation request to the data signal generation unit 19, the control signal generation unit 20, and the reference signal generation unit 21 based on each input information. Further, the scheduler 18 sends scheduling information indicating radio resource allocation for each signal to the allocation unit 24 based on each input information.
  • the data signal generator 19 generates a data signal based on the signal generation request from the scheduler 18.
  • the data signal encoding / modulating unit 22 performs encoding processing and modulation processing on the data signal generated by the data signal generating unit 19.
  • the encoded and modulated data signal obtained by the data signal encoding / modulating unit 22 is output to the assigning unit 24.
  • the control signal generation unit 20 generates a control signal based on the signal generation request from the scheduler 18.
  • the control signal encoding / modulating unit 23 performs encoding processing and modulation processing on the control signal generated by the control signal generating unit 20.
  • the encoded and modulated control signal obtained by the control signal encoding / modulating unit 23 is output to the allocating unit 24.
  • the reference signal generation unit 21 generates a reference signal based on the signal generation request from the scheduler 18.
  • the allocating unit 24 uses the scheduling information instructed by the scheduler 18 for the data signal from the data signal encoding and modulating unit 22, the control signal from the control signal encoding and modulating unit 23, and the reference signal from the reference signal generating unit 21.
  • Wireless resources are allocated.
  • the radio resources include, for example, transmission / reception power, transmission / reception frequency (channel), transmission / reception timing, and the like as examples of communication resources used for transmission / reception of radio signals.
  • the transmission unit 25 transmits a data signal, a control signal, and a reference signal via the antenna 11 using the radio resource allocated by the allocation unit 24.
  • the scheduler 18 performs radio resource allocation control. For example, as shown in FIG. 6, when the scheduler 18 starts radio resource allocation control (step S20), the scheduler 18 calculates the number of uplink radio resources that the UE 3 can use for transmission of SRS (step S21). Note that the number of uplink radio resources includes, for example, the number of resource blocks (RB, resource blocks) defined by the channel and transmission timing.
  • RB resource blocks
  • the scheduler 18 calculates the number of UEs 3 to which uplink radio resources for SRS transmission are allocated (step S22). Then, it is determined whether or not the number of UE3 is larger than the number of uplink radio resources (step S23). When it is determined that the number of UE3 is equal to or less than the number of uplink radio resources (No route of step S23), the scheduler 18 allocates different radio resources to each UE 3 (step S25), and ends the radio resource allocation control (step S26).
  • the scheduler 18 will allocate the same radio resource to any of the plurality of UE3.
  • the scheduler 18 in this example assigns the same radio resource to the UEs 3 having different radio areas in the same area (step S24), and ends the radio resource allocation control (step S26). Thereby, it is possible to prevent the SRS from the UE 3 to which the same radio resource is assigned in duplicate from colliding and interfering in the eNB 1 and the RRH 2 by the transmission power switching control of this example described later.
  • the scheduler 18 locates radio resources at least partially overlapping among the plurality of radio resources in the radio areas of the radio terminal 3 and other radio base stations 2 located in the radio area of the own station 1. It can be assigned to the wireless terminal 3.
  • the scheduler 18 performs transmission power switching control. For example, as shown in FIG. 7, when the scheduler 18 starts transmission power switching control (step S30), the scheduler 18 determines whether or not the same radio resource is allocated to different UEs 3 (step S31). If there is no radio resource duplication (No route in step S31), the transmission power switching control is terminated (step S34).
  • the scheduler 18 determines whether or not each UE 3 to which the same radio resource is assigned is an application target of CoMP (step S32). .
  • the scheduler 18 ends the transmission power switching control (Step S34). .
  • step S32 when it is determined that any of the UEs 3 to which the same radio resource is allocated is a CoMP application target (Yes route in step S32), the scheduler 18 Instructing UE 3 residing in a radio area provided by another station different from the radio area provided by own stations 1 and 2 to switch transmission power control (TPC) (step S33), the transmission power switching control is terminated (step S34).
  • TPC transmission power control
  • the scheduler 18 performs the following transmission power re-switching control after performing the process of step S33. For example, as shown in FIG. 8, when the scheduler 18 starts transmission power re-switching control (step S40), it is determined whether or not the situation where the same radio resource is allocated to different UEs 3 has been resolved. Determination is made (step S41).
  • the scheduler 18 uses the radio provided by the own stations 1 and 2 among the UEs 3 to which the same radio resource is allocated.
  • a UE 3 located in a radio area provided by another station different from the area is instructed to switch transmission power control (TPC) (step S43), and the transmission power re-switching control is terminated (step S43). Step S44).
  • the scheduler 18 determines whether or not at least one of the UEs 3 to which the same radio resource is allocated is not subject to CoMP application. Is determined (step S42). Here, if it is determined that at least one of the UEs 3 to which the same radio resource is assigned is not subject to CoMP application (Yes route in step S42), the scheduler 18 has been assigned the same radio resource. In addition, among the UEs 3, the transmission power control (TPC) is switched for the UEs 3 located in the wireless areas provided by other stations different from the wireless areas provided by the own stations 1 and 2. An instruction is given (step S43), and transmission power re-switching control is terminated (step S44).
  • TPC transmission power control
  • Step S44 when it is determined that each of the UEs 3 to which the same radio resource is allocated is a CoMP application target (No route in Step S42), the scheduler 18 ends the transmission power re-switching control (Step S44).
  • a transmission power control (TPC) switching instruction and a transmission power control (TPC) switching instruction will be described in detail.
  • the scheduler 18 When the TPC switching instruction shown in step S33 and the TPC re-switching instruction shown in step S43 are performed, the scheduler 18 generates an instruction signal for instructing the control signal generation unit 20 to switch the TPC. Request that.
  • the instruction signal is configured as, for example, a flag that can take two values “1” and “0”.
  • the scheduler 18 sets the instruction signal to “1” to cause the UE 3 to perform TPC according to the following control equation (1) from the following control equation (2).
  • the scheduler 18 allocates radio resources at least partially overlapping each other among the plurality of radio resources used when transmitting a known signal such as SRS to the plurality of radio terminals 3, Among the plurality of wireless terminals 3, a known signal transmitted by a wireless terminal 3 located in a wireless area of another wireless base station 2 different from the local station 1 is received by the wireless base station 2 except the local station 1.
  • a processing unit that controls the transmission power of the wireless terminal 3 located in the wireless area of the other wireless base station 2.
  • step S43 the scheduler 18 sets the instruction signal to “0” to cause the UE 3 to perform TPC according to the following control equation (1) to the following control equation (2).
  • the scheduler 18 transmits a radio terminal 3 located in a radio area of another radio base station 2 when different radio resources among a plurality of radio resources are allocated to a plurality of radio terminals.
  • the transmission power of the radio terminal 3 located in the radio area of the other radio base station 2 can be controlled so that the known signal is received at least by the own station 1 and the other radio base station 2.
  • the instruction signal may be stored and transmitted in downlink control information such as DCI (Downlink Control Information): A-CQI (Channel Quality Indicator) as shown in FIG. 9A, for example.
  • DCI Downlink Control Information
  • A-CQI Channel Quality Indicator
  • the instruction signal is added as a new field (srs-ConfigTPC) to a control signal in an upper layer such as SoundingRS-UL-Config of Radio ⁇ ⁇ ⁇ resource control information elements. May be sent.
  • FIG. 10 is a diagram illustrating an exemplary configuration of UE3.
  • the UE 3 shown in FIG. 10 exemplarily includes an antenna 31, a duplexer 32, a reception unit 33, a channel estimation unit 34, a control signal demodulation / decoding unit 35, a data signal demodulation / decoding unit 36, and a reception quality calculation.
  • the unit 37 is provided.
  • 10 exemplarily includes a data signal generation unit 38, a control signal generation unit 39, a reference signal generation unit 40, a data signal encoding modulation unit 41, and a control signal encoding modulation unit 42.
  • an allocating unit 43, a switching control unit 44, a transmission power determining unit 45, and a transmitting unit 46 exemplarily includes a Wi-Fi Protected Access (WPA)
  • a transmission power determining unit 45 a transmitting unit 46.
  • the antenna 31 functions as a reception antenna that receives radio signals from the eNB1 and RRH2, and also functions as a transmission antenna that transmits radio signals to the eNB1 and RRH2. That is, the antenna 31 of this example has a configuration in which the reception antenna and the transmission antenna are shared by the duplexer 32. Note that FIG. 10 merely shows an example of the configuration of the UE 3. For example, when the duplexer 32 is not used, the UE 3 may have a transmission antenna and a reception antenna individually.
  • the receiving unit 33 extracts a reference signal, a control signal, and a data signal from downlink radio signals, such as Physical31Downlink Shared Channel (PDSCH) and Physical Downlink Control Channel (PDCCH) transmitted from eNB1 and RRH2 received by the antenna 31. .
  • the reference signal, control signal, and data signal extracted by the reception unit 33 are output to the channel estimation unit 34, the control signal demodulation / decoding unit 35, and the data signal demodulation / decoding unit 36, respectively.
  • the channel estimation unit 34 calculates a channel estimation value using the reference signal extracted by the reception unit 33.
  • the channel estimation value calculated by the channel estimation unit 34 is output to the control signal demodulation / decoding unit 35, the data signal demodulation / decoding unit 36, and the reception quality calculation unit 37, respectively.
  • the control signal demodulation / decoding unit 35 uses the channel estimation value calculated by the channel estimation unit 34 to perform demodulation processing and decoding processing on the control signal extracted by the reception unit 33.
  • the control information obtained by the control signal demodulation / decoding unit 35 is output to the data signal demodulation / decoding unit 36, the control signal generation unit 39, the allocation unit 43, and the switching control unit 44, respectively.
  • ACK indicating that the decoding result is normal or NACK indicating that the decoding result is abnormal may be output to the control signal generation unit 39.
  • the data signal demodulation / decoding unit 36 performs demodulation processing and decoding processing on the data signal extracted by the receiving unit 33 using the channel estimation value calculated by the channel estimation unit 34.
  • the data obtained by the data signal demodulation / decoding unit 36 is output to the control signal generation unit 39. Further, ACK indicating that the decoding result is normal or NACK indicating that the decoding result is abnormal may be output to the control signal generation unit 39.
  • the reception quality calculation unit 37 calculates reception quality such as SIR using the channel estimation value calculated by the channel estimation unit 34. Information regarding the reception quality calculated by the reception quality calculation unit 37 is output to the control signal generation unit 39.
  • the data signal generation unit 38 generates a data signal.
  • the data signal encoding / modulating unit 41 performs encoding processing and modulation processing on the data signal generated by the data signal generating unit 38.
  • the encoded and modulated data signal obtained by the data signal encoding / modulating unit 41 is output to the assigning unit 43.
  • the control signal generation unit 39 generates a control signal based on various information from the control signal demodulation / decoding unit 35, the data signal demodulation / decoding unit 36, and the reception quality calculation unit 37.
  • the control signal encoding / modulating unit 42 performs encoding processing and modulation processing on the control signal generated by the control signal generating unit 39.
  • the encoded and modulated control signal obtained by the control signal encoding / modulating unit 42 is output to the allocating unit 43.
  • the reference signal generation unit 40 generates a reference signal.
  • the allocating unit 43 receives the data signal from the data signal encoding / modulating unit 41, the control signal from the control signal encoding / modulating unit 42, and the reference signal from the reference signal generating unit 40 from the control signal demodulation / decoding unit 35.
  • Radio resources are allocated based on the control information.
  • the radio resources include, for example, transmission / reception frequencies (channels), transmission / reception timings, and the like as examples of communication resources used for transmission / reception of radio signals. For example, when the number of UE3 is larger than the number of radio resources that can be allocated in eNB1 and RRH2, UE3 allocates the same radio resource as other UE3 as the radio resource used for SRS transmission.
  • the switching control unit 44 switches transmission power control (TPC) in the UE 3 based on the control information input from the control signal demodulation / decoding unit 35. Specifically, for example, when the control information input from the control signal demodulation / decoding unit 35 includes the instruction signal set to “1” as the above-described instruction signal, the switching control unit 44 uses the following control expression (2 ) To transmit power control according to the following control equation (1). When the control information input from the control signal demodulation / decoding unit 35 includes the instruction signal set to “0” as the above-described instruction signal, the switching control unit 44 transmits transmission power according to the following control expression (1). Control is switched to transmission power control according to the following control equation (2).
  • the transmission power determination unit 45 determines the transmission power of the UE 3 according to the transmission power control method after switching by the switching control unit 44. More specifically, the transmission power determination unit 45 determines the transmission power for the SRS according to the transmission power control equation after switching by the switching control unit 44. That is, the transmission power determination unit 45 is configured to respond to a plurality of wireless terminals 3 including the own station 3 with a plurality of wireless resources used when transmitting a known signal such as SRS, at least partially overlapping with each other. Processing for determining transmission power of own station 3 so that known signals transmitted by own station 3 are received by some radio base stations 2 (or 1) of a plurality of radio base stations when assigned It functions as an example of a unit.
  • the transmission unit 46 transmits a data signal, a control signal, and a reference signal via the antenna 31 using the radio resource allocated by the allocation unit 43 and the transmission power determined by the transmission power determination unit 45. That is, the transmission unit 46 functions as an example of a transmission unit that transmits a known signal using the transmission power determined by the transmission power determination unit 45.
  • step S50 when the UE 3 starts the SRS transmission process (step S50), the UE 3 extracts the instruction signal described above from the control information received from the eNB 1 and the RRH 2 (step S51).
  • UE3 switches the transmission power control method in the own station 3 according to the content of the extracted instruction
  • the UE 3 transmits at least a known radio signal transmitted by the own station 3 to the serving radio base.
  • the transmission power of the local station 3 can be determined so as to be received by the station 2 (or 1) and the other radio base station 1 (or 2).
  • UE3 determines the transmission power of SRS according to the transmission power control method (control formula) after switching in step S52 (step S53).
  • UE3 transmits SRS with the transmission power determined by step S53 (step S54), and complete
  • step S53 step S54
  • step S55 step S55
  • the radio resources for SRS transmission are insufficient, the influence of SRS collision due to the overlap of radio resources for SRS transmission can be reduced. It becomes possible to obtain a high-quality UL-CQI (UpLink-Channel Quality Indicator).
  • the eNB 1 can appropriately perform CoMP control, so that it is possible to maintain the data communication efficiency by CoMP.
  • eNB1 and RRH2 have determined whether TPC switching is necessary. However, as in this example, UE3 is notified of the presence or absence of radio resource duplication from eNB1 and RRH2. Based on the notification contents, it may be determined whether or not TPC switching is necessary. For example, as shown in FIG. 12, first, eNB1 or RRH2 assigns radio resources for SRS transmission to each UE3, and whether or not the same radio resources are assigned to different UE3 in duplicate. Is detected.
  • step S60 When it detects that the same radio resource is assigned to different UE3 in duplicate (duplication of SRS radio resource) (step S60), eNB1 or RRH2 detects at least one of UE3 to which the same radio resource is assigned. Then, it is notified that the radio resources for SRS transmission are allocated redundantly (step S61).
  • the UE 3 that is notified that the radio resources for SRS transmission are allocated redundantly performs, for example, transmission power control according to the following control equation (1) so that the SRS reaches only the serving cell ( Step S62), SRS is transmitted with the determined transmission power (step S63).
  • step S64 when eNB1 or RRH2 detects that the overlapping of the radio resources for SRS has been eliminated (step S64), among UE3 assigned with the same radio resource, UE3 that has instructed step S61 described above Then, it is notified that the SRS radio resource duplication has been resolved (step S65).
  • UE3 that has been notified that the duplication of SRS radio resources has been resolved for example, performs transmission power control according to the following control equation (2) so that the SRS reaches all reception points in the CoMP set. (Step S66), SRS is transmitted with the determined transmission power (Step S67).
  • the scheduler 18 performs radio resource allocation control. For example, as shown in FIG. 6, when the scheduler 18 starts radio resource allocation control (step S20), the scheduler 18 calculates the number of uplink radio resources that the UE 3 can use for transmission of SRS (step S21). Note that the number of uplink radio resources includes, for example, the number of resource blocks (RB) defined by the channel and transmission timing.
  • RB resource blocks
  • the scheduler 18 calculates the number of UEs 3 to which uplink radio resources for SRS transmission are allocated (step S22). Then, it is determined whether or not the number of UE3 is larger than the number of uplink radio resources (step S23). When it is determined that the number of UE3 is equal to or less than the number of uplink radio resources (No route of step S23), the scheduler 18 allocates different radio resources to each UE 3 (step S25), and ends the radio resource allocation control (step S26).
  • the scheduler 18 will allocate the same radio resource to any of the plurality of UE3.
  • the scheduler 18 in this example assigns the same radio resource to the UEs 3 having different radio areas in the same area (step S24), and ends the radio resource allocation control (step S26). Thereby, it is possible to prevent the SRS from the UE 3 to which the same radio resource is assigned in duplicate from colliding and interfering in the eNB 1 and the RRH 2 by the transmission power switching control of this example described later.
  • the scheduler 18 performs notification processing regarding the presence or absence of radio resource duplication. For example, as illustrated in FIG. 13, when the scheduler 18 starts notification processing about the presence or absence of radio resource duplication (step S ⁇ b> 70), the scheduler 18 determines whether or not the same radio resource is assigned to different UEs 3 in duplicate. If there is no radio resource duplication (No route in step S71), the notification process is terminated (step S74).
  • the scheduler 18 determines whether or not each UE 3 to which the same radio resource is assigned is a CoMP application target (step S72). .
  • the scheduler 18 ends the notification process (Step S74).
  • step S72 when it is determined that any of the UEs 3 to which the same radio resource is allocated is a CoMP application target (Yes route in step S72), the scheduler 18 Radio resources for SRS transmission are allocated to UE3 located in a radio area provided by another station different from the radio area provided by own stations 1 and 2 Then, it is notified that there is a possibility of interference of SRS (step S73), and the notification process is terminated (step S74).
  • the scheduler 18 performs the following re-notification process after performing the process of step S73. For example, as shown in FIG. 14, when the scheduler 18 starts the re-notification process (step S80), the scheduler 18 determines whether or not the situation in which the same radio resource is allocated to different UEs 3 has been resolved. (Step S81).
  • the scheduler 18 is the radio provided by the own stations 1 and 2 among the UEs 3 to which the same radio resource is allocated. Radio resources for SRS transmission are not allocated redundantly to UE3 located in a radio area provided by another station different from the area, and there is no possibility of SRS interference occurring This is notified (step S83), and the re-notification process is terminated (step S84).
  • the scheduler 18 determines whether or not at least one of the UEs 3 to which the same radio resource is assigned is not subject to CoMP application. Is determined (step S82).
  • the scheduler 18 has been allocated the same radio resource.
  • SRS interference may occur for UEs 3 located in radio areas provided by other stations different from the radio areas provided by the own stations 1 and 2. Notify (step S83), and the re-notification process ends (step S84).
  • Step S84 when it is determined that each of the UEs 3 to which the same radio resource is allocated is a CoMP application target (No route in Step S82), the scheduler 18 ends the re-notification process (Step S84).
  • the notification process and the re-notification process will be described in detail.
  • the scheduler 18 When performing the notification process shown in step S73 and the re-notification process shown in step S83, the scheduler 18 notifies the control signal generation unit 20 that radio resources are allocated in duplicate. Request to generate a signal.
  • the notification signal is configured as a flag that can take two values, for example, “1” and “0”. For example, in the above step S73, the scheduler 18 sets the notification signal to “1” to notify the UE 3 that the radio resource is allocated redundantly. In step S83, the scheduler 18 sets the instruction signal to “0” to notify the UE 3 that the radio resources are not allocated redundantly.
  • the notification signal may be transmitted by being stored in downlink control information such as DCI: A-CQI as shown in FIG. 15 (A), for example.
  • DCI downlink control information
  • A-CQI as shown in FIG. 15 (A)
  • the notification signal is added as a new field (srs-ConfigTPC) to a control signal in an upper layer such as SoundingRS-UL-Config of RadioConfigresource control information elements, for example, as shown in FIG. May be sent.
  • step S90 when the UE 3 starts the SRS transmission process (step S90), the UE 3 extracts the notification signal described above from the control information received from the eNB 1 and the RRH 2 (step S91).
  • UE3 switches the transmission power control method in the own station 3 according to the content of the extracted notification signal (step S92). Specifically, for example, when a notification signal set to “1” is extracted, the UE 3 switches from transmission power control according to the following control equation (2) to transmission power control according to the following control equation (1). When the notification signal set to “0” is extracted, the UE 3 switches from transmission power control according to the following control equation (1) to transmission power control according to the following control equation (2).
  • UE3 determines the transmission power of SRS according to the transmission power control method (control equation) after switching in step S92 (step S93). And UE3 transmits SRS with the transmission power determined by step S93 (step S94), and complete
  • control equation control equation
  • FIG. 17 shows an example of the hardware configuration of eNB1 and RRH2.
  • the eNB 1 and the RRH 2 include an antenna 11, a wireless IF (wireless interface) 51, a processor 52, a memory 53, a logic circuit 54, and a wired IF (wired interface) 55. .
  • the wireless IF 51 is an interface device for performing wireless communication with the UE 3.
  • the processor 52 is a device that processes data, and includes, for example, a Central Processing Unit (CPU), a Digital Signal Processor (DSP), and the like.
  • the memory 53 is a device that stores data, and includes, for example, Read Only Memory (ROM), Random Access Memory (RAM), and the like.
  • the logic circuit 54 is an electronic circuit that performs a logical operation, and includes, for example, Large Scale Integration (LSI), Field Programmable Gate Array (FPGA), and the like.
  • the wired IF 55 is an interface device for performing wired communication with another eNB 1 and another RRH 2.
  • the wireless IF 51 corresponds to, for example, the duplexer 12, the reception unit 13, and the transmission unit 25.
  • the processor 52, the memory 53, and the logic circuit 54 include, for example, a channel estimation unit 14, a control signal demodulation / decoding unit 15, a data signal demodulation / decoding unit 16, a reception quality calculation unit 17, a scheduler 18, a data signal generation unit 19, and a control signal generation. This corresponds to the unit 20, the reference signal generation unit 21, the data signal encoding / modulation unit 22, the control signal encoding / modulation unit 23, and the allocation unit 24.
  • FIG. 18 shows an example of the hardware configuration of UE3.
  • the UE 3 includes an antenna 31, a wireless IF 61, a processor 62, a memory 63, a logic circuit 64, an input IF (input interface) 65, and an output IF (output interface) 66.
  • the wireless IF 61 is an interface device for performing wireless communication with the eNB 1 and the RRH 2.
  • the processor 62 is a device that processes data, and includes, for example, a CPU and a DSP.
  • the memory 63 is a device that stores data, and includes, for example, a ROM, a RAM, and the like.
  • the logic circuit 64 is an electronic circuit that performs a logical operation, and includes, for example, an LSI, an FPGA, or the like.
  • the input IF 65 is a device that performs input, and includes, for example, an operation button, a microphone, and the like.
  • the output IF 66 is a device that performs output, and includes, for example, a speaker and a display.
  • the correspondence relationship between each configuration of UE 3 illustrated in FIG. 10 and each configuration of UE 3 illustrated in FIG. 18 is, for example, as follows.
  • the wireless IF 61 corresponds to, for example, the duplexer 32, the reception unit 33, and the transmission unit 46.
  • the processor 62, the memory 63, and the logic circuit 64 include, for example, a channel estimation unit 34, a control signal demodulation / decoding unit 35, a data signal demodulation / decoding unit 36, a reception quality calculation unit 37, a data signal generation unit 38, a control signal generation unit 39, This corresponds to the reference signal generation unit 40, the data signal encoding / modulating unit 41, the control signal encoding / modulating unit 42, the allocating unit 43, the switching control unit 44 and the transmission power determining unit 45.
  • each structure and each function of eNB1, RRH2, and UE3 in embodiment and the modification which were mentioned above may be selected as needed, and may be used in combination suitably.
  • the above-described configurations and functions may be selected or used in appropriate combination so that the functions of the present invention can be exhibited.
  • the SRS transmitted by the UE 3 is received only by the serving radio base station 2 (or 1).
  • the transmission power is controlled, for example, the transmission power of UE3 is set so that the SRS transmitted by UE3 is received by a plurality of radio base stations other than radio base station 1 (or 2) where interference of SRS may occur. You may control. Specifically, for example, the transmission power can be determined based on the distance between the UE 3 and each of the radio base stations 1 and 2, the radio communication environment, and the like.
  • the plurality of radio base stations excluding the radio base station 1 (or 2) in which SRS interference may occur include the serving radio base station 2 (or 1).
  • the transmission power control method of UE3 when radio resources for SRS transmission are allocated in duplicate, the transmission power control method of UE3 is switched as a plurality of SRSs can interfere.
  • the transmission power control method of UE 3 may be switched. Specifically, for example, in eNB1 and RRH2, SRS interference is detected by comparing the received power of each SRS, and based on the detection result, an instruction signal is transmitted to UE3 or a notification signal is transmitted. Then, the transmission power control method of UE3 may be switched.
  • the radio communication system 6 includes the eNB 1 as an example of the macro base station that covers a radio area of the order of several hundred meters to several km, and the extension station (RRH) 2.
  • the wireless communication system 6 is, for example, a micro base station (Micro eNB) that covers a wireless area on the order of several hundred meters, or a pico base that covers a wireless area on the order of several tens of meters to about 200 meters.
  • a station (Pico eNB), a home base station dedicated to a specific user (also referred to as a Home eNB or a femtocell base station), a relay station that relays a radio signal, and the like may be provided.
  • the micro base station, the pico base station, and the home base station may have the same configuration and function as the eNB 1 or the RRH 2 described above.
  • the transmission power control method of UE 3 is switched. May be switched to the UE 3 transmission power control method.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne une station de base sans fil (1), dans des cas dans lesquels une pluralité de ressources sans fil utilisées pour la transmission de signaux connus, les ressources sans fil étant au moins partiellement redondantes, sont attribuées à une pluralité de terminaux sans fil (3-1, 3-7), dans laquelle l'interférence des signaux connus est minimisée par la commande de la puissance de transmission du terminal sans fil (3-7), de manière à ce que le signal connu, transmis par le terminal sans fil (3-7), qui, parmi la pluralité de terminaux sans fil (3-1, 3-7) est celui qui est situé dans la zone sans fil (5-2) d'une autre station de base sans fil (2-2), différente de sa station d'attache (1), est reçu par la station de base sans fil (2-2), tout en excluant la station d'attache.
PCT/JP2012/061362 2012-04-27 2012-04-27 Station de base sans fil, terminal sans fil, système de communication sans fil et procédé de commande de communication Ceased WO2013161054A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2021100260A (ja) * 2016-05-05 2021-07-01 株式会社Ｎｔｔドコモ アップリンクパイロット及び分散されたユーザ近接検出に基づく基地局選択のメカニズム及び手順

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Publication number Priority date Publication date Assignee Title
JP2010199902A (ja) * 2009-02-24 2010-09-09 Kyocera Corp 無線基地局および送信電力制御方法
JP2011009866A (ja) * 2009-06-23 2011-01-13 Ntt Docomo Inc 無線基地局装置、移動端末装置及び送信電力制御方法
WO2012008593A1 (fr) * 2010-07-16 2012-01-19 京セラ株式会社 Station de base sans fil et procédé de commande de communication

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010199902A (ja) * 2009-02-24 2010-09-09 Kyocera Corp 無線基地局および送信電力制御方法
JP2011009866A (ja) * 2009-06-23 2011-01-13 Ntt Docomo Inc 無線基地局装置、移動端末装置及び送信電力制御方法
WO2012008593A1 (fr) * 2010-07-16 2012-01-19 京セラ株式会社 Station de base sans fil et procédé de commande de communication

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2021100260A (ja) * 2016-05-05 2021-07-01 株式会社Ｎｔｔドコモ アップリンクパイロット及び分散されたユーザ近接検出に基づく基地局選択のメカニズム及び手順

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