WO2013108317A1 - Système de communication sans fil, dispositif de commande de puissance d'émission, dispositif de station de base, dispositif de fourniture de paramètre et procédé de commande de puissance d'émission method - Google Patents

Système de communication sans fil, dispositif de commande de puissance d'émission, dispositif de station de base, dispositif de fourniture de paramètre et procédé de commande de puissance d'émission method Download PDF

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Publication number
WO2013108317A1
WO2013108317A1 PCT/JP2012/007013 JP2012007013W WO2013108317A1 WO 2013108317 A1 WO2013108317 A1 WO 2013108317A1 JP 2012007013 W JP2012007013 W JP 2012007013W WO 2013108317 A1 WO2013108317 A1 WO 2013108317A1
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WIPO (PCT)
Prior art keywords
uplink
transmission power
interference
cell
power control
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PCT/JP2012/007013
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English (en)
Japanese (ja)
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基樹 森田
濱辺　孝二郎
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日本電気株式会社
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Priority to JP2013554088A priority Critical patent/JP6070574B2/ja
Publication of WO2013108317A1 publication Critical patent/WO2013108317A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/18—TPC being performed according to specific parameters
    • H04W52/24—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters
    • H04W52/243—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters taking into account interferences
    • H04W52/244—Interferences in heterogeneous networks, e.g. among macro and femto or pico cells or other sector / system interference [OSI]

Definitions

  • the present invention relates to uplink transmission power control in a wireless communication system.
  • the femtocell base station not only accommodates the above-mentioned high-demand traffic, but can also be installed in places where radio waves do not reach, such as high floors of buildings and underground malls, so it is also attracting attention as a means of expanding coverage (communication area that satisfies the required quality) Has been.
  • Femtocell base stations are used in 3GPP (3rd Generation Partnership Project) W-CDMA and E-UTRA mobile phone wireless communication standards, and IEEE 802.16m wireless MAN (Wireless Metropolitan Area Network) wireless communication standards To be considered.
  • W-CDMA Wideband Code Division Multiple Access
  • a femtocell base station is called Home NodeB (HNB).
  • HNB Wideband Code Division Multiple Access
  • E-UTRA Evolved Universal Terrestrial Radio Access
  • LTE Long Term Evolution
  • LTE Long Term Evolution
  • the femtocell base station is connected to an upper network (e.g. a core network of an e.g. carrier) directly or via a femto GW (gateway).
  • the Femto GW is called Home NodeB Gateway in the W-CDMA standard and Home eNodeB Gateway in the E-UTRA standard.
  • a mobile station that communicates by connecting to a femtocell base station is called a “femtocell mobile station”, and a mobile station that communicates by connecting to a macro base station is called a “macro mobile station”. .
  • femtocell base stations When femtocell base stations are used in W-CDMA, data transmission / reception using dedicated channels with transmission power control in uplink (uplink) and downlink (downlink), and data using downlink shared channels Transmission / reception is performed.
  • a femtocell base station When a femtocell base station is used in E-UTRA, the radio frequency band and time are divided into a plurality of resource blocks (PRBs), and a scheduler provided in the base station assigns PRBs. And data transmission / reception using the assigned PRB is performed.
  • PRBs resource blocks
  • OFDMA Orthogonal Frequency Division Multiple Multiple Access
  • CSG ClosedCloseSubscriber Group
  • CSG cell a cell to which only the mobile station belonging to the CSG is allowed.
  • CSG when a mobile station is located in a femtocell, a mobile station registered in the femtocell base station can connect to the network via the femtocell base station.
  • a mobile station that is not registered in the femtocell base station cannot be connected to the network via the femtocell base station, or communication with the femtocell base station is restricted compared to a registered mobile station.
  • uplink interference means interference that the uplink reception of the base station (in other words, uplink transmission of the mobile station) suffers from the uplink transmission of the mobile station of another cell. That is, in this interference scenario, the interference that the uplink transmission of the femtocell mobile station has on the uplink reception of the macro base station (in other words, the uplink transmission of the macro mobile station) is targeted.
  • This interference scenario is particularly problematic when the upstream frequency bands of the femto cell and the macro cell are the same, the femto cell is a CSG cell, and the femto cell base station is located near the macro base station.
  • the transmission power of the macro mobile station located near the femtocell base station is relatively small, the interference of the uplink transmission of the femtocell mobile station on the uplink transmission of the macro mobile station becomes serious.
  • Non-Patent Documents 1 and 2 and Patent Document 1 disclose techniques for suppressing uplink interference from a femto cell to a macro cell.
  • Non-Patent Documents 1 and 2 disclose that the uplink transmission power of the femtocell is controlled in consideration of the propagation loss between the femtocell and the macrocell. Specifically, Non-Patent Document 1 measures the propagation loss between the femtocell base station and the macro base station, and the transmission power control is performed so that the uplink transmission power of the femtocell mobile station is smaller as the propagation loss is smaller. Is disclosed.
  • Non-Patent Document 2 measures the propagation loss between the femtocell mobile station and the macro base station, and performs transmission power control so that the uplink transmission power of the femtocell mobile station is smaller as the propagation loss is smaller.
  • the transmission power control includes adjustment of the uplink target reception power in the femtocell base station and adjustment of the maximum uplink transmission power in the femtocell mobile station.
  • Patent document 1 pays attention to the fact that the number of femtocell base stations arranged in a macro cell changes, and from a plurality of femtocells arranged in a macrocell to a macrocell regardless of the number of femtocell base stations in the macrocell.
  • the purpose is to suppress uplink interference.
  • Patent Document 1 discloses the following technique. That is, the number of femtocell base stations having a femtocell mobile station in communication among a plurality of femtocell base stations arranged in the macro cell is obtained.
  • the upper limit value I cap of the allowed uplink interference amount per femtocell base station is calculated by dividing the allowable value of the total uplink interference amount received by the macro base station by the obtained number of femtocell base stations. To do. Then, each femtocell base station considers the propagation loss PL up between the femtocell and the macrocell, and the maximum transmission power P of the femtocell mobile station so that the uplink interference given to the macrocell does not exceed the upper limit value I cap. Determine MAX .
  • Patent Document 1 obtains the number of femtocell base stations having femtocell mobile stations that are arranged in a macro cell and is in communication, and uses this number to determine the uplink of the femtocell mobile station. Control transmission power.
  • Patent Document 1 divides the allowable amount of uplink interference in a macro base station by the number of femtocell base stations, and sets the upper limit value I cap of the allowable uplink interference per femtocell base station for each femtocell base station. Is equally charged.
  • Patent Document 1 does not consider that a plurality of femtocell base stations receive uplink interference having different sizes.
  • the magnitude of the received uplink interference is also different from each other.
  • a femtocell base station that receives relatively low uplink interference is more likely to reduce uplink transmission power than other femtocell base stations arranged at the same distance from the macro base station. This is because the received femtocell base station with small uplink interference has a high possibility of ensuring the same uplink communication quality as other femtocell base stations even if the uplink transmission power is reduced.
  • the femtocell base station receiving relatively large uplink interference reduces the uplink transmission power according to the upper limit I cap of the uplink interference amount imposed equally with other femtocell base stations. There is a risk that the required upstream communication quality cannot be ensured.
  • Non-Patent Documents 1 and 2 only disclose that the uplink transmission power of the femtocell is controlled in consideration of the propagation loss between the femtocell and the macrocell. That is, the uplink transmission power control described in Non-Patent Documents 1 and 2 does not directly consider the uplink interference received by the femtocell.
  • Patent Document 1 is not limited to an environment that uses a macro cell and a femto cell, but can generally occur in an environment in which a plurality of small cells overlap with a large cell.
  • Such an environment is called a hierarchical cell structure (Hierarchical Cell Structure (HCS)) or Heterogeneous Network (HetNet).
  • HCS Hierarchical Cell Structure
  • HetNet Heterogeneous Network
  • the present invention has been made based on the above-mentioned knowledge obtained by the inventors. That is, according to the present invention, in an environment in which a plurality of small cells overlap with a large cell, the uplink communication quality of the small cell is excessively deteriorated due to suppression of uplink interference to the large cell. It is an object of the present invention to provide a wireless communication system, a transmission power control device, a base station device, a parameter supply device, a transmission power control method, and a program that can contribute to prevention of noise.
  • the first aspect of the present invention includes a wireless communication system.
  • the wireless communication system includes a first base station, a plurality of second base stations, a parameter supply device, and a control device.
  • the first base station forms a first cell.
  • the plurality of second base stations form a plurality of second cells each smaller than the first cell and at least partially overlapping the first cell.
  • the parameter supply device includes: a first uplink interference received by a target cell included in the plurality of second cells; and a plurality of second cells based on index information indicating the uplink interference received by each second cell.
  • the interference parameter reflecting the difference in magnitude from the second uplink interference received by the other cells included in is supplied.
  • the control device performs uplink transmission power control on the target cell using the interference parameter.
  • the second aspect of the present invention includes a transmission power control device used in a wireless communication system.
  • the wireless communication system forms a first base station forming a first cell, and a plurality of second cells, each of which is smaller than the first cell and at least partially overlaps the first cell.
  • a plurality of second base stations are included.
  • the transmission power control apparatus includes: a first uplink interference received by a target cell included in the plurality of second cells; and a second uplink interference received by another cell included in the plurality of second cells. It is configured to perform uplink transmission power control for the target cell using an interference parameter reflecting the difference in size.
  • the third aspect of the present invention includes a base station apparatus.
  • the base station apparatus includes the above-described transmission power control apparatus according to the second aspect of the present invention and a radio communication unit capable of communicating with mobile stations belonging to the target cell.
  • the 4th aspect of this invention contains the parameter supply apparatus used with a radio
  • the wireless communication system forms a plurality of second cells, each of which is smaller than the first cell and at least partially overlaps with the first cell, forming a first cell.
  • a control device that performs uplink transmission power control on a plurality of second base stations and target cells included in the plurality of second cells formed by the plurality of second base stations. Then, the parameter supply device, based on index information indicating uplink interference received by each second cell, the first uplink interference received by the target cell included in the plurality of second cells and the plurality of second cells An interference parameter reflecting a difference in magnitude from the second uplink interference received by other cells included in the other cell is supplied to the control means for the uplink transmission power control.
  • the fifth aspect of the present invention includes a transmission power control method used in a wireless communication system.
  • the wireless communication system forms a first base station forming a first cell, and a plurality of second cells, each of which is smaller than the first cell and at least partially overlaps the first cell.
  • a plurality of second base stations are included.
  • the transmission power control method includes: a first uplink interference received by a target cell included in the plurality of second cells; and a second uplink interference received by another cell included in the plurality of second cells. And performing uplink transmission power control on the target cell using an interference parameter reflecting the difference in size of the target cell.
  • the sixth aspect of the present invention includes a program for causing a computer to perform the transmission power control method according to the fifth aspect of the present invention described above.
  • the uplink communication quality of the small cell is reduced due to the suppression of uplink interference to the large cell. It is possible to provide a wireless communication system, a transmission power control device, a base station device, a parameter supply device, a transmission power control method, and a program that can contribute to prevention of excessive reduction.
  • FIG. 4 is a block diagram showing a configuration example of a transmission power control apparatus shown in FIGS.
  • FIG. 4 is a block diagram showing a configuration example of a parameter supply device shown in FIGS. It is a flowchart which shows the specific example of the uplink transmission power control by a transmission power control apparatus.
  • FIG. 1 shows a network configuration example of a radio communication system according to Embodiment 1 of the present invention.
  • the wireless communication system according to the present embodiment includes a plurality of femtocell base stations 1 and macro base stations 3.
  • Each femtocell base station 1 forms a femtocell 5 and performs wireless communication with the femtocell mobile station 2.
  • the macro base station 3 forms a macro cell 6 and performs wireless communication with the macro mobile station 4.
  • Each femtocell 5 at least partially overlaps the macrocell 6.
  • the plurality of femtocell base stations 1 includes two femtocell base stations 1-1 and 1-2. Femtocell base stations 1-1 and 1-2 form femtocells 5-1 and 5-2, respectively.
  • the femtocells 5-1 and 5-2 at least partially overlap the macrocell 6.
  • the femtocell base station 1-1 performs radio communication with the femtocell mobile station 2-1 in the femtocell 5-1.
  • the femtocell base station 1-2 performs radio communication with the femtocell mobile station 2-2 in the femtocell 5-2.
  • the femtocells 5-1 and 5-2 that overlap with the macrocell 6 exert uplink interference on the macrocell 6. That is, the uplink transmissions of the femtocell mobile stations 2-1 and 2-2 interfere with uplink reception of the macro base station 3 (in other words, uplink transmission of the macro mobile station 4).
  • the transmission power control apparatus 10 performs uplink transmission power control (uplink TPC (Transmission Power Control)) of the femtocell 5.
  • uplink TPC Transmission Power Control
  • the transmission power control apparatus 10 may be configured to control the uplink transmission power of a plurality of femtocells 5 (for example, the cells 5-1 and 5-2). Moreover, in order to perform uplink transmission power control of the plurality of femtocells 5, a separate transmission power control apparatus 10 may be arranged for each femtocell 5.
  • Transmission power control unit 10 similarly to the method described in Non-Patent Documents 1 and 2, taking into consideration the propagation loss L M between the femtocell 5-1 and the macrocell 6, be subjected to uplink transmission power control Good.
  • the propagation loss L M may be used the propagation loss between the femto cell mobile station 2-1 and the macro base station 3, using a propagation loss between the femto cell base station 1-1 and the macro base station 3 May be.
  • the transmission power controller 10 may perform transmit power control to reduce the transmission power of the femtocell mobile station 2-1 as the propagation loss L M is small.
  • the uplink transmission power of the femtocell mobile station 2-1 may be adjusted according to the uplink transmission power control method defined by W-CDMA, E-UTRA, IEEE 802.16m, or the like.
  • the transmission power control apparatus 10 may adjust the uplink target received power PO_H in the femtocell base station 1-1.
  • the femtocell base station 1-1 controls the transmission power of the femtocell mobile station 2-1 so that the received power of the uplink signal from the femtocell mobile station 2-1 approaches the uplink target received power PO_H .
  • the femtocell base station 1-1 may notify the uplink target received power PO_H to the femtocell mobile station 2-1. Further, the femtocell base station 1-1 may instruct the femtocell mobile station 2-1 to increase or decrease the transmission power so as to approach the uplink target reception power PO_H by so-called closed loop transmission power control. Further, the transmission power control apparatus 10 may adjust the maximum transmission power P MAX, H of the femtocell mobile station 2-1 instead of the uplink target reception power PO_H .
  • the transmission power control apparatus 10 uses the interference parameter PI in the uplink transmission power control of the femtocell 5-1.
  • the interference parameter PI includes uplink interference received by a target cell (cell 5-1) included in a plurality of femtocells 5 (here, cells 5-1 and 5-2) and uplink received by another cell (cell 5-2). The difference in size from interference is reflected.
  • the uplink interference received by the target cell (cell 5-1) is received from the uplink transmission by the macro mobile station 4 located near the target cell (cell 5-1) by the femtocell base station 1-1.
  • uplink interference received by another cell (cell 5-2) means that uplink reception by the femtocell base station 1-2 is uplink transmission by the macro mobile station 4 located near the other cell (cell 5-2). It is interference received from.
  • the interference parameter PI is determined according to the amount of uplink interference received by the target cell (cell 5-1). Therefore, generally, the interference parameter PI has a different value between femtocells having different amounts of uplink interference received.
  • the interference parameter PI is used to correct any parameter used for controlling the uplink transmission power of the femtocell mobile station 2-1.
  • the interference parameter PI may be defined as a correction parameter for correcting the uplink target received power PO_H in the femtocell base station 1-1.
  • the interference parameter PI may be defined as a correction parameter for correcting the maximum transmission power P MAX, H of the femtocell mobile station 2-1.
  • the upper limit value of the uplink interference amount that each femtocell 5 gives to the macrocell 6 is not shared among the plurality of femtocells 5, but the femtocell 5 5 can be determined for each femtocell 5 depending on the magnitude of uplink interference received by the F5.
  • the upper limit of the uplink interference amount that the femtocell 5 exerts on the macro cell 6 is increased (that is, mitigated).
  • the upper limit of the amount of uplink interference that the femtocell 5 exerts on the macrocell 6 is reduced (that is, stricter).
  • the transmission power control apparatus 10 is a case where both the target cell (cell 5-1) and the other cell (cell 5-2) are arranged at the same propagation loss from the macro base station 3.
  • a difference may be provided between the upper limit of uplink interference.
  • the other cell (cell 5-2) the other cell (cell 5-2)
  • the uplink transmission power control of the femtocell mobile station 2-1 is performed so that the upper limit of the uplink interference given to the macro cell 6 by the target cell (cell 5-1) is larger than the upper limit of the given uplink interference.
  • the interference parameter PI for the target cell (cell 5-1) is the uplink interference that the other cell (cell 5-2) gives to the macro cell 6 by the uplink transmission power control by the transmission power control apparatus 10.
  • the upper limit of uplink interference that the target cell (cell 5-1) gives to the macro cell 6 is determined to be larger than the upper limit.
  • the uplink target received power P O_H in the femto cell base station 1-1 be provided with a difference between the uplink target received power P O_H in the femto cell base station 1-2 Also good.
  • the transmission power control apparatus 10 transmits the other cell (cell 5).
  • the interference parameter PI for the target cell (cell 5-1) is obtained by the femtocell base station 1-2 of another cell (cell 5-2) by the uplink transmission power control by the transmission power control apparatus 10. is determined as the uplink target received power P O_H in the femto cell base station 1-1 of the subject cell as compared to the upstream target received power P O_H (cell 5-1) increases the.
  • the parameter supply apparatus 20 includes an index (hereinafter, referred to as an index indicating the magnitude of uplink interference received by each femtocell 5 (each femtocell base station 1) from each of the plurality of femtocells 5 (multiple femtocell base stations 1). Receive uplink interference index). Then, the parameter supply device 20 generates an interference parameter PI based on the received uplink interference index of each femtocell 5, and uses the generated parameter PI for transmission power control for uplink transmission power control of the target femtocell 5-1. Supply to device 10. The parameter supply device 20 may supply the interference parameter PI to each of the plurality of transmission power control devices 10 for uplink transmission power control of the plurality of femtocells 5.
  • an index hereinafter, referred to as an index indicating the magnitude of uplink interference received by each femtocell 5 (each femtocell base station 1) from each of the plurality of femtocells 5 (multiple
  • the uplink interference index collected by the parameter supply device 20 only needs to indicate the magnitude of the uplink interference received by each femtocell 5.
  • the uplink interference indicator includes uplink interference power, Interference over Thermal (IoT), or Overload Indicator (OI).
  • IoT Interference over Thermal
  • OI Overload Indicator
  • the uplink interference power is the reception power of the uplink interference signal that the femtocell base station 1 receives from the mobile stations belonging to the neighboring cells.
  • IoT [dB] is a relative value of the upstream interference power to the thermal noise power.
  • the OI is an index representing the magnitude of uplink interference power defined and used in LTE.
  • transmission power control apparatus 10 uses interference parameter PI for uplink transmission power control in target femtocell 5-1.
  • the interference parameter PI includes uplink interference received by a target cell (cell 5-1) included in a plurality of femtocells 5 (here, cells 5-1 and 5-2) and uplink received by another cell (cell 5-2). It reflects the difference in size from interference.
  • the magnitude of uplink interference received also differs from each other.
  • the femtocell base station 1 that receives relatively small uplink interference is more likely to reduce the uplink transmission power than other femtocell base stations 1 arranged at the same distance from the macro base station. This is because the femtocell base station 1 that receives small uplink interference has a high possibility of securing the same uplink communication quality as other femtocell base stations 1 even if the uplink transmission power is reduced.
  • the femtocell base station 1 receiving relatively large uplink interference reduces the uplink transmission power according to the upper limit I cap of the uplink interference amount imposed equally with the other femtocell base stations 1.
  • the uplink transmission power control in the present embodiment takes into account the difference in the magnitude of uplink interference received by the plurality of femtocells 5 and the degree of restriction imposed for suppressing uplink interference to the macrocell 6 Can be changed for each femtocell 5.
  • the restrictions imposed for suppressing uplink interference to the macro cell 6 include, for example, reduction of the upper limit value of uplink interference from the femtocell 5 to the macro cell 6, reduction of uplink target received power in the femtocell base station 1, or The maximum transmission power of the femtocell mobile station 2 is reduced.
  • the arrangement of the transmission power control device 10 and the parameter supply device 20 is appropriately determined based on the design concept of the network architecture or according to the wireless communication standard.
  • the transmission power control apparatus 10 may be disposed integrally with the femtocell base station 1.
  • the parameter supply device 20 may be arranged in the management server 151 that can communicate with the plurality of femtocell base stations 1 via the upper network 150.
  • the upper network 150 includes, for example, a radio access network and a core network of a communication carrier, an IP (Internet Protocol) leased line, and the public Internet.
  • both the transmission power control device 10 and the parameter supply device 20 may be arranged integrally with the femtocell base station 1. Further, the functions of the transmission power control apparatus 10 may be separately arranged in the wireless communication system. For example, the function of uplink transmission power control by the transmission power control apparatus 10 may be realized by the femtocell mobile station 2, the femtocell base station 1, and a control apparatus (eg RNC (Radio Network Controller)) in the upper network 150. Good.
  • RNC Radio Network Controller
  • the transmission power control apparatus 10 may be arranged in the femtocell mobile station 2-1.
  • the femtocell mobile station 2-1 may receive the interference parameter PI from the femtocell base station 1-1 or the management server 151 and correct its own uplink transmission power using the parameter PI.
  • FIG. 4 is a block diagram illustrating a configuration example of the transmission power control apparatus 10.
  • the transmission power control apparatus 10 includes an uplink transmission power control unit 11.
  • the uplink transmission power control unit 11 receives the interference parameter PI from the parameter supply device 20. Then, the uplink transmission power control unit 11 performs uplink transmission power control of the femtocell mobile station 2 belonging to the target femtocell 5 using the parameter PI.
  • the uplink transmission power control includes, for example, adjustment of the uplink target reception power PO_H in the femtocell base station 1, or adjustment of the maximum transmission power PMAX , H of the femtocell mobile station 2-1.
  • FIG. 5 is a block diagram illustrating a configuration example of the parameter supply device 20.
  • the parameter supply device 20 includes an interference parameter generation unit 21 and an interference parameter transmission unit 22.
  • the interference parameter generation unit 21 collects uplink interference indices for each of the plurality of femtocells 5. Then, the interference parameter generation unit 21 generates an interference parameter PI related to the target cell (here, the cell 5-1) in consideration of the magnitude relationship of the received plurality of uplink interference indices.
  • the uplink interference index of each femtocell 5 is sent to the interference parameter generation unit 21 from a control device such as the femtocell base station 1 or the RNC, for example.
  • the interference parameter transmission unit 22 supplies the generated interference parameter PI to the transmission power control apparatus 10.
  • FIG. 6 is a flowchart showing a specific example of uplink transmission power control by the transmission power control apparatus 10.
  • the transmission power control apparatus 10 receives the interference parameter PI from the parameter supply apparatus 20.
  • the interference parameter PI is a parameter reflecting a difference in magnitude between uplink interference received by the target femtocell (cell 5-1) and uplink interference received by another femtocell (cell 5-2).
  • the transmission power control apparatus 10 performs uplink transmission power control on the target femtocell 5 using the interference parameter PI.
  • FIG. 7 is a flowchart showing the operation of the parameter supply device 20.
  • the parameter supply device 20 receives the uplink interference indicator for each of the plurality of femtocells 5.
  • the parameter supply device 20 generates an interference parameter PI related to the target cell (here, the cell 5-1) in consideration of the magnitude relationship of the received plurality of uplink interference indices.
  • the parameter supply device 20 transmits the interference parameter PI to the transmission power control device 10.
  • the target uplink received power P O_H, i at the femtocell base station 1-1 is described.
  • the subscript i means the i-th of the plurality of femtocells 5 (the plurality of femtocell base stations 1).
  • the interference parameter PI is used for uplink transmission power control as the “correction parameter ⁇ i” for the uplink target received power PO_H, i .
  • the total number of the plurality of femtocell base stations 1 including the femtocell base station 1-1 to be controlled is N.
  • an estimated value ⁇ of SINR (Signal to Interference plus Noise Ratio) per uplink PRB transmitted by the macro mobile station 4 when it is assumed that the macro mobile station 4 is in the vicinity of the femtocell base station 1-1 to be controlled is defined [dB]. Assume that ⁇ must be greater than or equal to ⁇ MIN .
  • ⁇ MIN [dB] is the minimum SINR value required for the uplink communication quality of the macro mobile station 4 to satisfy a predetermined quality. ⁇ MIN is set in advance.
  • interference power the interference power I H [dBm] that the femtocell mobile station 2-1 belonging to the femtocell base station 1-1 to be controlled gives to the uplink reception (desired wave) of the macro base station 3,
  • other femtocell mobile stations such as mobile station 2-2 located in the macrocell 6.
  • a plurality of macro mobile stations 4 located in one macro cell 6 use different PRBs. Therefore, it can be assumed that interference from other macro mobile stations located in one macro cell 6 is zero.
  • ⁇ can be approximately defined by the following equation (1).
  • S M [dBm] is the desired wave power, that is, the uplink received power from the macro mobile station 4 in the macro base station 3.
  • N the uplink interference power from the N femtocell 5 is N times the uplink interference power I H per 5 one femtocell.
  • N described in Equation (1) is logarithmic. Thereby, the contribution from the some femtocell 5 located in the same macrocell 6 is considered. It is also assumed that thermal noise is negligible.
  • uplink transmission power control is performed so that the average uplink transmission power P UL, j, i [dBm] per PRB follows the following equation (2).
  • j is a subscript representing M or H, and corresponds to the macro mobile station 4 or the femtocell mobile station 2, respectively.
  • P MAX, j [dBm] is the maximum uplink transmission power.
  • P O — j [dBm] is the uplink target received power.
  • L i, j is a propagation loss L M, i between the macro base station 3 and the femtocell mobile station 2-1, since it is assumed that there is one femtocell mobile station per femtocell.
  • a propagation loss LH a propagation loss LH , i .
  • the propagation loss between the macro base station 3 and the macro mobile station 4 is the same as that of the macro base station 3 and the femto cell base station 1-1.
  • ⁇ j is a correction value applied to the propagation loss L M, i and L H, i .
  • S M and I H can be expressed by the following equations (3-1) and (3-2).
  • the second term on the right side corresponds to the transmission power of the macro mobile station 4. Since it is assumed that the macro mobile station 4 is located in the vicinity of the femtocell base station 1-1, the propagation loss from the macro mobile station 4 to the macro base station 3 is reduced from the femtocell mobile station 2-1 to the macro base station 3 Can be assumed to be equal to the propagation loss L M until. Therefore, the equation (3-1) indicates that the uplink signal (transmission power P O_M + ⁇ M L M, i ) of the macro mobile station 4 receives the propagation loss L M, i, and receives the propagation power L M at the macro base station 3. It means that it is received by.
  • the second term on the right side corresponds to the transmission power of the femtocell mobile station 2-1. Therefore, the equation (3-2) indicates that the uplink signal (transmission power P O_H, i + ⁇ H L H, i ) of the femtocell mobile station 2-1 receives the propagation loss L M, i and receives the reception power I H Means that it is received by the macro base station 3.
  • correction parameter ⁇ i as the interference parameter PI is added to the uplink target received power PO_H, i is shown.
  • Correction parameter .DELTA.i uplink target received power P O_H by being added to i, the femtocell mobile station 2-1 is the interference power I H to be supplied to the macro base station 3 is changed by .DELTA.i.
  • the condition that the equal sign of Expression (1) is satisfied corresponds to a situation where the SINR of the desired wave signal in the macro base station 3 is minimized.
  • the condition for satisfying the equality in equation (1) corresponds to a situation where the sum of the uplink interference power from the plurality of femtocell mobile stations 2 is the upper limit.
  • the transmission power of the femtocell mobile station 2-1 is the maximum value allowed (however, different from P MAX, j ). Therefore, the upper limit of the interference power I H to which the correction parameter ⁇ i is added can be expressed as the following equation (4).
  • Equation (5) the uplink target received power PO_H, i in the target femtocell 5-1 can be formulated as Equation (5).
  • the fifth term ( ⁇ 10 Log 10 N) on the right side of Equation (5) is a value that is commonly determined for all femtocells 5, and takes into account the total number N of the plurality of femtocells 5. This means that the allowable amount of uplink interference is divided by N. That is, the fifth term on the right side means that the upper limit of the amount of uplink interference allowed per femtocell base station is equally imposed on each femtocell base station 1.
  • the sixth term (+ ⁇ i) on the right side of the equation (5) is the magnitude of the uplink interference received by the target femtocell 5-1, particularly the other femtocell (cell 5-2 etc.). It is determined in consideration of the difference from the magnitude of uplink interference.
  • ⁇ i a specific example of how to obtain ⁇ i will be described.
  • Equation (4) results of I H summed over all of the plurality of femtocell base station 1 of, to be equal to the summing result before the addition of .DELTA.i. Therefore, when the total uplink interference power experienced by the macro base station 3 is unchanged, the following equation (6) is established.
  • ⁇ i is determined so as to increase as the uplink interference received by the target femtocell base station 1-1 increases.
  • the reason is that, when the uplink interference received by the target femtocell base station 1-1 is relatively large, the uplink transmission power of the femtocell mobile station 2-1 is increased as much as possible so that the target femtocell 5-1 Uplink communication quality can be ensured.
  • the uplink interference received by the target femtocell base station 1-1 is relatively small, the uplink communication quality of the target femtocell 5-1 even if the uplink transmission power of the femtocell mobile station 2-1 is reduced. This is because it can be secured.
  • ⁇ i may be defined as a monotonically increasing function of an uplink interference index representing the magnitude of uplink interference received by the target femtocell base station 1-1.
  • the uplink interference index is Interference over Thermal (IoT)
  • ⁇ i may be defined as a monotonically increasing function of IoT TH , i .
  • IoT H, i represents the IoT received by the target femtocell base station 1-1.
  • Specific examples of the monotone increasing function, IoT H, i becomes zero minimum value - ⁇ max next ⁇ i is at a minimum value, IoT H, i is the ⁇ i when more than a predetermined value Io the maximum value .DELTA.max 1
  • IoT H, i is the ⁇ i when more than a predetermined value Io the maximum value .DELTA.max 1
  • ⁇ i can be formulated as the following equation (7).
  • ⁇ max can be obtained by setting Io to a predetermined value (for example, 10 dB) and substituting Equation (7) into Equation (6).
  • Formula (7) is an example, and if ⁇ i satisfies the condition that the relationship of Formula (6) and the monotonically increasing function are satisfied, the formulation of ⁇ i is arbitrary.
  • the upper limit of the total uplink interference in the macro base station 3 is independent of the number of femtocell base stations 1 installed and the femtocell mobile stations 2 Regardless of the adjustment of the transmission power, the value is determined by subtracting ⁇ MIN from the reception power S M of the uplink signal (desired wave) reaching the macro base station 3 from the macro mobile station 4. Therefore, the communication quality (ie SINR) of the uplink signal of the macro cell 6 can be expected to be equal to or higher than ⁇ MIN .
  • the reduction amount of interference power required to make the upper limit of uplink interference received by the macrocell 6 constant (that is, S M - ⁇ MIN ) can be expressed as a plurality of femto values.
  • the cells 5 can be distributed with weights rather than evenly. That is, for the femtocell 5 that receives only relatively small uplink interference, the transmission power of the femtocell mobile station 2 belonging to the femtocell 5 can be reduced.
  • the transmission power of the femtocell mobile station 2 belonging to the femtocell 5 can be increased by allocating the lowered amount in other cells. .
  • “the transmission power of the femtocell mobile station 2” may be read as “an upper limit value of the amount of uplink interference exerted on the macrocell 6 by the femtocell 5”.
  • FIG. 8 is a block diagram showing a configuration example of a radio communication system according to the present embodiment.
  • the femtocell base station 1-1 has the function of the transmission power control apparatus 10 (uplink transmission power control unit 11).
  • the uplink transmission power control unit 11 illustrated in FIG. 8 includes a PI acquisition unit 110 and an uplink TPC setting unit 111.
  • the PI acquisition unit 110 receives the interference parameter PI (in this case, the correction parameter ⁇ i) from the interference parameter transmission unit 22 arranged in the management server 151.
  • the PI acquisition unit 110 may receive the number N of the plurality of femtocells 5 (the plurality of femtocell base stations 1) together with the interference parameter PI (correction parameter ⁇ i).
  • the uplink TPC setting unit 111 generates uplink target received power PO_H, i reflecting the interference parameter PI, and supplies this to the radio communication unit 100.
  • the radio communication unit 100 transmits a downlink signal encoded with control data and user data to the femtocell mobile station 2-1. Also, the radio communication unit 100 receives an uplink signal transmitted from the femtocell mobile station 2-1, and decodes received data from the uplink signal. Further, the radio communication unit 100 transmits the uplink target received power PO_H, i to the femtocell mobile station 2-1.
  • the broadcast information acquisition unit 101 receives a broadcast signal transmitted from the macro base station 3 into the macro cell 6 via the radio. Broadcast information acquisition section 101 restores broadcast information from the received broadcast signal, and acquires macro cell transmission power information included in the broadcast information.
  • the macro cell transmission power information includes (1) a transmission power P TX_M [dBm] of a downlink reference signal transmitted from the macro base station 3, and (2) an uplink target reception power used for determining an uplink transmission power in the macro mobile station 4.
  • P O_M [dBm] and (3) a correction coefficient ⁇ M for the propagation loss used for determining the uplink transmission power in the macro mobile station 4.
  • the broadcast information acquisition unit 101 is, for example, in Network Listening Mode (NLM) that is activated periodically (eg, several hours to 1 day) during the initial installation of the femtocell base station 1 or during operation of the femtocell base station 1.
  • NLM Network Listening Mode
  • the notification information acquisition operation may be performed.
  • the measurement report acquisition unit 102 receives received power (RSRP: Reference Signal Received Power) P RX_H [dBm] of the downlink reference signal transmitted from the femtocell base station 1-1 and the downlink reference signal transmitted from the macro base station 3.
  • the measurement report including the measurement result of the received power P RX_M [dBm] is received from the femtocell mobile station 2-1.
  • the interference indicator reporting unit 103 transmits an uplink interference indicator indicating the magnitude of the uplink interference received by the femtocell base station 1-1 to the interference parameter generating unit 21 of the management server 151.
  • the femtocell base station 1-1 may measure the magnitude of the received uplink interference periodically (e.g., about 100 milliseconds).
  • the magnitude of uplink interference may be measured as an absolute value (e.g. dBm unit) of received power or may be measured as IoT (e.g. dB unit).
  • the magnitude of the uplink interference power may be measured as another parameter such as Overload / Indicator (OI) used in LTE.
  • OFI Overload / Indicator
  • the OI may be a value indicating one of three states (i.e. “interference high level, interference low level, interference low level) corresponding to the magnitude of uplink interference.
  • the uplink interference index reported to the management server 151 may be generated using a moving average value calculated using a plurality of periodic uplink interference measurement values.
  • the interference indicator reporting unit 103 may report the uplink interference indicator to the management server 151 using a report cycle (e.g. 10 seconds or so) longer than the uplink interference measurement cycle.
  • the radio communication unit 200 transmits an uplink signal in which control data and user data are encoded to the femtocell base station 1-1.
  • Radio communication section 200 receives a downlink signal transmitted from femtocell base station 1-1, and decodes received data from the downlink signal. Further, the radio communication unit 200 supplies the uplink target received power PO_H, i received from the femtocell base station 1-1 to the uplink transmission power determining unit 202.
  • Received power measuring unit 201 measures the femtocell base station 1-1 RSRP (P RX_H), the macro base station 3 RSRP the (P RX_M). These measurements may be performed at a predetermined cycle (eg about 100 milliseconds).
  • the base station to be measured (the femtocell base station 1-1 and the macro base station 3) and the measurement item (RSRP) are specified by the femtocell base station 1-1 sending a Measurement Control message to the femtocell mobile station 2-1. To do so. Then, the reception power measurement unit 201 reports the measurement results of P RX_H and P RX_M to the femtocell base station 1-1 via the wireless communication unit 200.
  • the report may be performed in a predetermined cycle (eg about 1 second).
  • the reported measurement results of P RX_H and P RX_M may be values filtered using a predetermined weighting factor. Further, the reported measurement result of P RX_H and P RX_M may be a moving average value calculated using a plurality of measurement values.
  • Uplink transmission power determining section 202 determines uplink transmission power P UL, H by radio communication section 200 using uplink target received power PO_H, i received from femtocell base station 1-1.
  • the uplink transmission power determination unit 202 may determine the uplink transmission power P UL, H according to the above equation (2).
  • the operations of the interference parameter generation unit 21 and the transmission unit 22 arranged in the management server 151 are basically the same as the operations described with reference to FIG. 5 in the first embodiment of the invention.
  • the interference parameter transmission unit 22 transmits an interference parameter PI (correction parameter ⁇ i) to the target femtocell base station 1-1.
  • the cycle in which the interference parameter transmission unit 22 transmits the interference parameter PI is an arbitrary cycle (eg 100 seconds) longer than the reporting cycle of the uplink interference index from the plurality of femtocell base stations 1. Degree).
  • the interference parameter transmission unit 22 may transmit the number N of the plurality of femtocells 5 (the plurality of femtocell base stations 1) together with the interference parameter PI (correction parameter ⁇ i).
  • FIG. 9 is a flowchart showing a specific example of uplink transmission power control by femtocell base station 1-1 according to the present embodiment.
  • the femtocell base station 1-1 transmits an uplink interference indicator related to the femtocell 5-1 that it manages to the management server 151.
  • parameters necessary for calculating the uplink target received power PO_H, i are acquired or generated using the above-described equation (5).
  • the femtocell base station 1-1 receives broadcast information transmitted from the macro base station 3, and acquires macro cell transmission power information included in the broadcast information.
  • the macro cell transmission power information includes P TX_M , P O_M , and ⁇ M.
  • the femtocell base station 1-1 receives the RSRP (P RX_M and P RX_H ) of the macro cell 6 and the femto cell 5-1 managed by the femto cell base station 2-1 from the femto cell mobile station 2-1.
  • the femtocell base station 1-1 moves the femtocell between the macro base station 3 and the femtocell mobile station 2-1, the propagation loss L M, i , and itself (the femtocell base station 1-1).
  • the propagation loss L H, i between the stations 2-1 is calculated.
  • Propagation loss L M, i can be calculated by the difference between the P TX_M and the macrocell 6 of RSRP contained in the macro cell transmission power information (P RX_M).
  • the propagation loss L H, i can be calculated from the difference between the transmission power P TX_H of the base station 1-1 itself and RSRP (P RX_H ).
  • L M is calculated here, i and L H, i is strictly a propagation loss of the downlink, assuming no significant difference in the loss characteristics in the frequency of the downlink uplink And used as uplink propagation loss.
  • step S35 the femtocell base station 1-1 receives the interference parameter PI from the management server 151.
  • step S36 the femtocell base station 1-1 uses the values obtained in steps S32 to S35 to calculate the uplink target received power PO_H, i according to equation (5).
  • FIG. 10 is a flowchart showing a specific example of the operation of the femtocell mobile station 2-1.
  • the femtocell mobile station 2-1 measures the RSRP (P RX_M and P RX_H ) of the macro cell 6 and the femto cell 5-1 to which the femto cell 5-1 belongs.
  • the femtocell mobile station 2-1 transmits the measurement result of RSRP (P RX_M and P RX_H ) to the femtocell base station 1-1.
  • step S43 the femtocell mobile station 2-1 determines whether or not the updated value of the uplink target received power PO_H, i has been received from the femtocell base station 1-1.
  • the femtocell mobile station 2-1 adjusts the uplink transmission power P UL, H using the updated value of the uplink target received power P O_H, i.
  • Adjusting uplink transmission power P UL, H is, P O_H, using the updated value of i may be performed by calculating the updated value of the uplink transmission power P UL, H according to equation (2).
  • FIG. 11 is a flowchart showing a specific example of the procedure for supplying the interference parameter PI by the management server 151.
  • the management server 151 receives an uplink interference indicator from each of the plurality of femtocell base stations 1.
  • the management server 151 generates at least the interference parameter PI (here, the correction parameter ⁇ i) related to the target femtocell 5-1 in consideration of the magnitude relationship of the plurality of uplink interference indices related to the plurality of femtocells 5.
  • the management server 151 transmits the interference parameter PI (correction parameter ⁇ i) to the target femtocell base station 1-1.
  • the management server 151 may transmit the number N of the plurality of femtocells 5 (the plurality of femtocell base stations 1) together with the interference parameter PI (correction parameter ⁇ i).
  • ⁇ Third Embodiment of the Invention> a specific example of the above-described first embodiment of the present invention will be described.
  • the functions of the transmission power control apparatus 10 and the parameter supply apparatus 20 are both arranged in the femtocell base station 1 as in the configuration example of FIG. That is, the plurality of femtocell base stations 1 exchange uplink interference indices with each other.
  • a communication interface usable between the base stations for example, an X2 interface standardized by 3GPP may be used.
  • FIG. 12 is a block diagram showing a configuration example of the radio communication system according to the present embodiment.
  • the femtocell base station 1-1 has the functions of a transmission power control device 10 (uplink transmission power control unit 11) and a parameter supply device 20 (interference parameter generation unit 21).
  • the interference parameter generation unit 21 receives an uplink interference index from another femtocell base station 1 instead of the management server 151, and generates an interference parameter PI.
  • the uplink transmission power control unit 11 illustrated in FIG. 12 includes an uplink TPC setting unit 111.
  • the uplink TPC setting unit 111 generates the uplink target received power PO_H in which the interference parameter PI generated by the interference parameter generation unit 21 is reflected, and supplies this to the radio communication unit 100.
  • the interference indicator reporting unit 103 shown in FIG. 12 transmits the uplink interference indicator of the femtocell 5-1 to the other femtocell base station 1 instead of the management server 151.
  • FIG. 13 is a flowchart showing a specific example of uplink transmission power control by the femtocell base station 1-1 according to the present embodiment.
  • Steps S32 to S34 and Step S36 shown in FIG. 13 are the same as Steps S31 to S34 and Step S36 shown in FIG.
  • the femtocell base station 1-1 transmits the uplink interference indicator of the own cell 5-1 to each of the other femtocell base stations 1.
  • step S651 the femtocell base station 1-1 receives the uplink interference indicator of each femtocell 5 from each of the other femtocell base stations 1.
  • step S652 the femtocell base station 1-1 considers the magnitude relationship between the uplink interference index of the other femtocell 5 and the uplink interference index of the own cell 5-1, and sets the interference parameter PI (eg correction parameter ⁇ i). Generate.
  • the interference parameter PI eg correction parameter ⁇ i
  • the uplink interference index is exchanged between the plurality of femtocell base stations 1. Therefore, this embodiment has an advantage that the management server 151 is not required.
  • Embodiments 2 and 3 the uplink interference index indicating the uplink interference received by each of the plurality of femtocells 5 (the plurality of femtocell base stations 1) is collected, and the macrocell 6 (the macro base station 3) An example in which the interference parameter PI is determined so that the sum of the uplink interference received from the plurality of femtocells 5 is constant has been shown.
  • the uplink SINR ⁇ of the macro cell 6 shown in the equation (1) becomes the minimum value ⁇ MIN as a result of receiving the uplink interference from the plurality of femtocells 5
  • the interference parameter PI eg correction parameter ⁇ i
  • the uplink target received power PO_H, i according to 5 e.g., the uplink target received power PO_H, i according to 5
  • This condition corresponds to a situation where the sum of the uplink interference power from the plurality of femtocell mobile stations 2 is the upper limit. Accordingly, the uplink transmission power of the entire plurality of femtocells 5 can be maximized while maintaining the uplink communication quality of the macrocell 6, and thus the uplink radio capacity of the entire plurality of femtocells 5 can be increased.
  • the 14A and 14B are diagrams showing uplink interference received by the macro base station 3 for convenience. That is, the examples described in the second and third embodiments of the invention correspond to making the interference 501 shown in FIG. 14A constant regardless of before and after the addition of the interference parameter PI.
  • the interference 501 represents the uplink interference that the macro base station 3 receives from the uplink transmissions of all the femtocell mobile stations 1 belonging to the plurality of femtocells 5.
  • the condition imposed to determine the interference parameter PI is not limited to the condition that “the sum of the uplink interference received by the macro cell 6 (macro base station 3) from the plurality of femto cells 5 is constant”. Three variations are shown below.
  • Modification 1 The condition that “the sum of the uplink interference received by the macro cell 6 (macro base station 3) from the plurality of femto cells 5 is equal to or less than a predetermined allowable value” is imposed. This condition corresponds to the interference 501 shown in FIG. 14A being set to a predetermined allowable value or less. This condition is equivalent to the following equation (8).
  • the parameter supply device 20 determines the interference parameter (eg correction parameter ⁇ i) using the equation of the monotonically increasing function of Equation (7) under the condition that Equation (8) holds. That's fine.
  • the parameter supply device 20 may hold the threshold value I2_threshold in advance.
  • the parameter supply device 20 may receive I2_threshold from the macro base station 3.
  • the parameter supply device 20 may hold S M - ⁇ MIN in advance. In this case, the desired wave received power S M of the macro base station 3 may be substituted by the uplink target received power P O_M of the macro base station 3.
  • S M - ⁇ MIN , or S M and ⁇ MIN may be reported from the femtocell base station 1 to the parameter supply device 20 (eg, the management server 151).
  • the femtocell base station 1 may acquire S M - ⁇ MIN or S M and ⁇ MIN from the macro cell transmission power information included in the broadcast information of the macro base station 3.
  • Modification 2 The condition that “all uplink interference received by the macro cell 6 (macro base station 3) is constant” is imposed. This condition corresponds to making the sum of the interferences 501 and 502 shown in FIG. 14B constant regardless of before and after the addition of the interference parameter PI.
  • Interference 502 represents uplink interference that the macro cell 6 receives from other cells (eg, other macro cells, other femto cells) except the plurality of femto cells 5. Moreover, this condition can be expressed as, for example, the following formula (9).
  • Equation (9) means that the amount of change per unit time of all uplink interference I3 received by the macro cell 6 is equal to or less than a predetermined threshold I3_offset.
  • I3 (t) is a measured value of all uplink interference I3 at time t.
  • the parameter supply device 20 eg management server 151 determines the interference parameter (eg correction parameter ⁇ i) using the equation of the monotonically increasing function of Equation (7) under the condition that Equation (9) holds. That's fine.
  • the parameter supply apparatus 20 may receive the measurement result of the all-up interference I3 received by the macro cell 6 from the macro base station 3.
  • the parameter supply device 20 e.g. management server 151 may hold the threshold value I3_offset in advance.
  • the parameter supply device 20 e.g. management server 151 may receive the threshold value I3_offset from the macro base station 3.
  • the uplink communication quality of the macro mobile station 4 can be more reliably maintained.
  • Modification 3 The condition that “all uplink interference received by the macro cell 6 (macro base station 3) is equal to or less than a predetermined allowable value” is imposed. This condition corresponds to the sum of the interferences 501 and 502 shown in FIG. 14B being equal to or less than a predetermined allowable value. Moreover, this condition can be expressed as, for example, the following formula (10).
  • Equation (9) means that the total uplink interference I3 received by the macro cell 6 is equal to or less than a predetermined threshold I3_threshold.
  • the parameter supply device 20 eg management server 151 determines the interference parameter (eg correction parameter ⁇ i) using the monotonically increasing function equation of Equation (7) under the condition that Equation (10) holds. That's fine.
  • the parameter supply apparatus 20 may receive the measurement result of the all-up interference I3 received by the macro cell 6 from the macro base station 3. Further, the parameter supply device 20 (e.g. management server 151) may hold the threshold value I3_threshold in advance. The parameter supply device 20 (e.g. management server 151) may receive the threshold value I3_threshold from the macro base station 3.
  • the configuration example in which one management server 151 exists for one macro cell 6 has been described.
  • the number of management servers 151 per macro cell 6 is not limited to one.
  • the management server 151 may supply the interference parameter PI with respect to the plurality of macro cells 6 and the plurality of femto cells 5 overlapping with these.
  • the number of management servers 151 per macro cell 6 is less than one. It is also possible that the number of management servers 151 per macro cell 6 is 1 or more.
  • a set of femtocell base stations 1 managed by one management server 151 becomes a part of the plurality of femtocell base stations 1 arranged in the macro cell 6.
  • the uplink interference index or the interference parameter PI may be exchanged between the plurality of management servers 151.
  • the parameter supply device 20 may be arranged in another device.
  • the parameter supply device 20 may be arranged in an LTE wireless communication system, the parameter supply device 20 may be arranged in an OAM (Operation & Maintenance) server corresponding to the management server 151, or may be an MME (Mobility Management Entity), S-GW (Serving Gateway). ) Or the HeNB GW.
  • the parameter supply device 20 may be arranged in the HNB GW or in the RNC.
  • Embodiment 3 of the invention an example in which uplink interference indicators are exchanged between a plurality of femtocell base stations 1 has been described.
  • the plurality of femtocell base stations 1 are in an equal relationship with each other.
  • the relationship between the plurality of femtocell base stations 1 is not necessarily equal, and for example, at least one femtocell base station 1 serving as an anchor may be set in advance in the macro cell 6.
  • each femtocell base station 1 may report an uplink interference indicator to the anchor femtocell base station 1.
  • the anchor femtocell base station 1 may generate the interference parameter PI and notify the femtocell base station 1 of the interference parameter PI in the same manner as the management server 151.
  • the role of the anchor may be always performed by a specific femtocell base station 1 or may be changed between a plurality of femtocell base stations 1 at a predetermined period.
  • Embodiments 2 and 3 of the invention have described the case where the number of femtocell mobile stations 2 connected to the femtocell base station 1 is one. However, the number of femtocell mobile stations 2 connected to the femtocell base station 1 may be plural. In this case, first, the femtocell base station 1 may obtain the uplink target received power PO_H for each femtocell mobile station 2 as in Embodiment 2 or 3. In the LTE scheme, generally, the uplink target reception power PO_H for each mobile station is set by adding correction for each mobile station to the reference value of the uplink target reception power for each cell.
  • the femtocell base station 1 next obtains the average value (or median value) of the uplink target received power that is commonly applied to the plurality of femtocell mobile stations 2, and calculates the difference with respect to this average value for each femtocell movement. What is necessary is just to obtain
  • the femtocell base station 1 may notify each femtocell mobile station 2 of the obtained average value and difference. Note that the femtocell base station 1 may notify each femtocell mobile station 2 of only the average value as the common uplink target reception power among the plurality of femtocell mobile stations 2.
  • ⁇ Other embodiment F> In the first to third embodiments of the present invention, a HetNet environment in which a macro cell and a plurality of femto cells are arranged in an overlapping manner has been described.
  • the application destination of the present invention is not limited to an environment including a macro cell and a plurality of femto cells.
  • an environment in which a plurality of pico cells and macro cells having a communication area larger than that of a femto cell base station are mixed may be used.
  • the uplink transmission power control described in Embodiments 1 to 3 of the invention can be applied for uplink transmission power control of a pico cell.
  • the picocell base station may acquire necessary information from the macro base station using the inter-base station interface (eg X2 interface) without depending on the broadcast information from the macro base station.
  • the present invention can be applied to any HetNet environment such as a mixed environment of macro cells, pico cells, and femto cells, and a mixed environment of macro cells and micro cells.
  • ⁇ Other embodiment G In the second and third embodiments of the present invention, the example in which the interference parameter PI is reflected in the uplink target received power PO_H is shown. However, as described in the first embodiment of the present invention, the target that reflects the interference parameter PI in the uplink transmission power control of the femtocell 5 is not limited to the uplink target received power PO_H . For example, the interference parameter PI may be reflected in the maximum transmission power P MAX, H of the femtocell mobile station 2.
  • the uplink interference given to the macro base station 3 is allowed even if the uplink transmission power fluctuation of the femtocell mobile station 2 may be large. The following can be stably suppressed.
  • Equation (12) the maximum uplink transmission power P MAX of the femtocell mobile station 2-1 , H, i can be formulated as in equation (12).
  • P MAX, M a value (for example, 23 dBm) defined in 3GPP as the maximum transmission power of the mobile station may be used.
  • the number of femtocells (number of femtocell base stations) N is supplied to the femtocell base station 1-1 (transmission power control unit 11) together with the interference parameter PI (specifically, the correction parameter ⁇ i).
  • the interference parameter PI specifically, the correction parameter ⁇ i.
  • the number of femtocells (the number of femtocell base stations) N is not necessarily supplied. In this case, “ 10 Log 10 N” in Expressions (5) and (9) may be fixedly set in advance as an interference margin.
  • the transmission power control apparatus 10 or the femtocell base station 1-1 acquires the number of femtocell base stations 1 installed in the macro cell 6 from the upper network 150 or the management server 151, A certain ratio (for example, 10%) may be used as the above-mentioned number of femtocells (number of femtocell base stations) N.
  • Embodiments 2 and 3 of the invention have been described for the case where the present invention is applied to an LTE (E-UTRA) wireless communication system.
  • the wireless communication system to which the present invention is applied is not particularly limited.
  • a W-CDMA system may be used, or a wireless communication system that employs a TDD (Time Division Duplex) system in which the same radio frequency is divided in time in the uplink and downlink (eg, WiMAX, IEEE 802.16)
  • TDD Time Division Duplex
  • WiMAX Time Division Duplex
  • ⁇ Other embodiment J> The processing of the transmission power control device 10 and the parameter supply device 20 described in the first to third embodiments of the invention is implemented using a semiconductor processing device including an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), and the like. May be. These devices may be mounted by causing a computer such as a microprocessor to execute a program. Specifically, a program including an instruction group for causing a computer to execute the algorithm shown in any of FIGS. 6, 7, 9, 11, and 13 may be created and supplied to the computer.
  • ASIC Application Specific Integrated Circuit
  • DSP Digital Signal Processor
  • Non-transitory computer readable media include various types of tangible storage media (tangible storage medium). Examples of non-transitory computer-readable media include magnetic recording media (eg flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (eg magneto-optical discs), CD-ROMs (Read Only Memory), CD-Rs, CD-R / W, semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable ROM), flash ROM, RAM (random access memory)) are included.
  • the program may also be supplied to the computer by various types of temporary computer-readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves.
  • the temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.
  • Uplink transmission power control unit 20 Parameter supply device 21
  • Interference parameter generation unit 22
  • Interference parameter transmission unit 100
  • Wireless communication unit 101
  • Broadcast information acquisition unit 102
  • Measurement report acquisition unit 103
  • Uplink RUR report unit 110
  • Interference parameter (PI) acquisition unit 111
  • Uplink TPC setting unit 150
  • Host network 151
  • Management server 200
  • Wireless communication unit 201
  • Received power measurement unit 202

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  • Mobile Radio Communication Systems (AREA)

Abstract

Selon l'invention, une première station de base (3) forme une première cellule (6). De multiples secondes stations de base (1-1 et 1-2) forment des secondes cellules (5-1 et 5-2) qui chevauchent au moins partiellement la première cellule (6). Sur la base d'un indice de brouillage de liaison montante indiquant le brouillage de liaison montante reçu par chacune des secondes cellules (5-1 et 5-2), un dispositif de fourniture (20) fournit un paramètre de brouillage (PI) qui reflète la différence d'amplitude entre un premier bouillage de liaison montante reçu par une cellule cible (5-1) des secondes cellules (5-1 et 5-2) et le second brouillage reçu par l'autre seconde cellule (5-2). Le dispositif de commande (10) commande la puissance d'émission de liaison montante de la cellule cible (5-1) par utilisation du paramètre de brouillage (PI).
PCT/JP2012/007013 2012-01-17 2012-11-01 Système de communication sans fil, dispositif de commande de puissance d'émission, dispositif de station de base, dispositif de fourniture de paramètre et procédé de commande de puissance d'émission method WO2013108317A1 (fr)

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WO2017119026A1 (fr) * 2016-01-07 2017-07-13 パナソニックＩｐマネジメント株式会社 Dispositif de communication et procédé de communication
JP2017531384A (ja) * 2014-09-30 2017-10-19 日本電気株式会社 ホーム基地局のためのアップリンクターゲット受信電力を設定するための通信システム
JP2020053788A (ja) * 2018-09-26 2020-04-02 ソフトバンク株式会社 大ゾーンセル基地局、地上セル基地局、それらを備えたシステム、及び、基地局管理装置

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WO2009072355A1 (fr) * 2007-12-03 2009-06-11 Nec Corporation Système de communication sans fil, procédé de commande de communication, station sans fil et support d'enregistrement
WO2011055555A1 (fr) * 2009-11-09 2011-05-12 パナソニック株式会社 Dispositif de microstation de base et procédé de commande de puissance d'émission
WO2011162395A1 (fr) * 2010-06-21 2011-12-29 Ntt Docomo, Inc. Procédé de commande de télécommunications, système de télécommunications et appareil de station de base

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JP5340995B2 (ja) * 2010-02-26 2013-11-13 株式会社日立製作所 基地局、無線通信システム及び干渉基準のハンドオーバ制御方法

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WO2009072355A1 (fr) * 2007-12-03 2009-06-11 Nec Corporation Système de communication sans fil, procédé de commande de communication, station sans fil et support d'enregistrement
WO2011055555A1 (fr) * 2009-11-09 2011-05-12 パナソニック株式会社 Dispositif de microstation de base et procédé de commande de puissance d'émission
WO2011162395A1 (fr) * 2010-06-21 2011-12-29 Ntt Docomo, Inc. Procédé de commande de télécommunications, système de télécommunications et appareil de station de base

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017531384A (ja) * 2014-09-30 2017-10-19 日本電気株式会社 ホーム基地局のためのアップリンクターゲット受信電力を設定するための通信システム
WO2017119026A1 (fr) * 2016-01-07 2017-07-13 パナソニックＩｐマネジメント株式会社 Dispositif de communication et procédé de communication
JP2020053788A (ja) * 2018-09-26 2020-04-02 ソフトバンク株式会社 大ゾーンセル基地局、地上セル基地局、それらを備えたシステム、及び、基地局管理装置

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