WO2012043307A1 - 無線通信システムと方法並びに無線端末、無線局、及び運用管理サーバ装置 - Google Patents
無線通信システムと方法並びに無線端末、無線局、及び運用管理サーバ装置 Download PDFInfo
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- WO2012043307A1 WO2012043307A1 PCT/JP2011/071390 JP2011071390W WO2012043307A1 WO 2012043307 A1 WO2012043307 A1 WO 2012043307A1 JP 2011071390 W JP2011071390 W JP 2011071390W WO 2012043307 A1 WO2012043307 A1 WO 2012043307A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W24/00—Supervisory, monitoring or testing arrangements
- H04W24/10—Scheduling measurement reports ; Arrangements for measurement reports
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W24/00—Supervisory, monitoring or testing arrangements
- H04W24/02—Arrangements for optimising operational condition
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
- H04W16/24—Cell structures
- H04W16/32—Hierarchical cell structures
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W84/00—Network topologies
- H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
- H04W84/04—Large scale networks; Deep hierarchical networks
- H04W84/042—Public Land Mobile systems, e.g. cellular systems
- H04W84/045—Public Land Mobile systems, e.g. cellular systems using private Base Stations, e.g. femto Base Stations, home Node B
Definitions
- the present invention relates to a communication system, and more particularly, to a wireless communication system, method, and apparatus suitable for application to a system that controls coverage and interference based on measurements performed on a wireless terminal side.
- LTE Long Term Evolution
- SON Self Organizing Network
- Non-Patent Documents 1, 2, and 3 Non-Patent Documents 1, 2, and 3).
- SON technology automatically changes, sets and optimizes coverage (cell size), capacity (capacity), interference, cell topology, frequency allocation, bandwidth, etc.
- Radio parameters to realize these Transmission power of a radio base station (eNodeB or eNB: evolved Node B or enhanced Node B, or simply “base station”), ⁇ The antenna tilt angle of the radio base station, -Neighbor cell information, There are handover parameters, etc., and one of these wireless parameters can be achieved at a wireless base station or an operation management server (OAM (Operation Administration and Maintenance) server or SON server) so as to achieve the above-mentioned purpose. Or, change the plurality as appropriate.
- OAM Opera Management and Maintenance
- FIG. 10 is a diagram for explaining a related technique for optimizing coverage between macro cells and macro cells.
- the radio base stations (eNB 1 and eNB 2) of the macro cell are connected to an operation management server (OAM / SON server).
- OAM / SON server operation management server
- the eNB 1 sends the UE the reception quality of the downlink reference signal from the eNB 1 (Downlink Reference Signal: also known as “pilot signal”) and the radio base stations eNB (for example, the radio base station 2 ( The reception quality of the downlink reference signal from the eNB 2)) is measured, and an instruction is issued so as to be reported when a predetermined condition is satisfied.
- the UE measures the reception quality of the downlink reference signal and reports the measurement result of the reception quality of the downlink reference signal to eNB1 (Measurement report).
- the eNB 1 reports the measurement result reported from the UE to the OAM / SON server (Report).
- the OAM / SON server Report
- the eNB 2 also reports the measurement result from the UE under its control to the OAM / SON server.
- the OAM / SON server that has received the measurement result report from eNB 1 and eNB 2 instructs eNB 1 and eNB 2 to adjust radio parameters and the like for optimization of radio coverage (Adjustment for Optimization).
- the own cell coverage optimization (adjustment of transmission power, antenna tilt angle, etc.) is executed. .
- FIG. 11 quotes the diagram described in Non-Patent Document 4.
- the reception quality measured by the radio terminal (UE) is a desired signal power to interference signal power ratio (Ec / Io).
- Ec / Io is measured by the radio terminal (UE), and the measurement result is reported to the radio base station.
- the base station or OAM the statistical information of the measurement result is acquired.
- R (the ratio of terminals whose Ec / Io exceeds the threshold) Is calculated.
- the base station or the OAM reduces the transmission power of the radio base station by a unit step.
- the base station or the OAM increases the transmission power of the radio base station by a unit step.
- RSRQ Reference Signal Received Quality
- 3GPP TS36.300 v9.4.0 Internet ⁇ http://www.3gpp.org/ftp/Specs/html-info/36300.htm>
- 3GPP TR36.902 v9.2.0 Internet ⁇ http://www.3gpp.org/ftp/Specs/html-info/36902.htm>
- NGMN Informative List of SON Use Cases Internet ⁇ http://www.ngmn.org/uploads/media/NGMN_Informative_List_of_SON_Use_Case.pdf>) Jana Laiho, Achim Wacker, Thomas Novosad, “Radio Network Planning and Optimization for UMTS”, John Wiley & Sons, pp.
- R2-105238 (3GPP TS37.320 v1.0.0 (2010-08)) (Internet ⁇ http://www.3gpp.org/ftp/tsg_ran/WG2_RL2/TSGR2_71/Docs/R2-105238.zip>)
- R2-103942 (Internet ⁇ http://www.3gpp.org/ftp/tsg_ran/WG2_RL2/TSGR2_70bis/Docs/R2-103942.zip>
- 3GPP TS36.304 v9.3.0 Internet ⁇ http://www.3gpp.org/ftp/Specs/html-info/36304.html>
- 3GPP TR21.905 v10.2.0 Internet ⁇ http://www.3gpp.org/ftp/Specs/archive/21_series/21.905/21905-a20.zip>)
- femto (cell) base stations also referred to as “Femto eNB” or home base station (“HeNB”)
- Femto eNB home base station
- HeNB home base station
- Ec / Io is the total power including the interference component for the desired signal (in the case of Ec / Io, from all cells that may cause interference).
- the signal power is derived as a ratio of the total power including the desired signal in the case of RSRQ.
- the radio terminal (UE) staying in the macro cell of the macro radio base station (eNB) receives strong interference from the femto base station in the own macro cell or the adjacent macro cell, the reception quality in the macro cell is the same as that of the femto base station.
- the eNB degrades the area of the macro cell unnecessarily.
- a dead zone (also referred to as “coverage hole”) may occur in the macro cell.
- the dead zone refers to an area where a wireless terminal cannot receive basic services from a wireless base station.
- FIG. 12 is a diagram for explaining this problem.
- the radio terminal (UE) stays in the macro cell 1 (Cell 1) of the radio base station 1 (eNB 1), and the adjacent cells are the cells Cell 2 and 3 of the radio base stations 2 and 3 (eNB 2 and 3). Close to the femtocell in Cell2.
- the radio terminal (UE) When the radio terminal (UE) receives strong interference from the femto base station (HeNB) in the adjacent macro cell Cell2, it reports to the first radio base station (eNB1) that the reception quality is degraded ( 1: Meas report).
- HeNB femto base station
- eNB1 the first radio base station
- the radio base station 1 (eNB 1) reports a report from the radio terminal (UE) to the OAM / SON server (2: Report).
- the OAM / SON server causes the radio base station 1 (eNB 1) to reduce the coverage of the cell Cell 1 (3: Adjustment).
- a plurality of radio terminals (UE) staying in the macro cell (Cell 1) of the radio base station 1 (eNB 1) are strongly affected by interference from the femto base station (HeNB), and the reception quality in the macro cell is deteriorated due to other cell interference.
- HeNB femto base station
- the number of reports indicating that this has increased is greater than before the introduction of femto base stations.
- the radio base station 1 (eNB 1) unnecessarily reduces the coverage of the macro cell Cell1. As a result, a coverage hole (dead zone) may occur.
- an object of the present invention is to provide a system, method, and apparatus that can identify interference factors and perform appropriate optimization processing for each interference factor.
- the present invention is generally configured as follows.
- a first radio station a second radio station of the same type as the first radio station, and / or a third radio station different from the first radio station
- a wireless terminal belonging to the first wireless station and an operation management server that exchanges setting information with at least one of the first to third wireless stations
- the first radio station instructs the radio terminal to measure the reception quality of downlink signals from one or more second or third radio stations
- the wireless terminal has a measurement unit that performs measurement according to the instruction
- At least one of the first radio station and the operation management server receives a measurement result report from the radio terminal, identifies the type of the radio station from the report, and determines the first to third radio stations.
- a wireless communication system including means for determining whether or not to change a wireless network setting of at least one wireless station and executing at least one of the changing of the wireless network setting.
- one or more second radio stations of the same type as the first radio station and / or the first radio station from the first radio station to the radio terminal And instructing the measurement of the reception quality of the downlink signal from the third radio station of a different type,
- the wireless terminal performs measurement according to the instruction, By at least one of the first wireless station and the operation management server, Receiving a measurement result report from the wireless terminal, identifying the type of the wireless station from the report, and determining whether or not it is necessary to change the wireless network setting of at least one of the first to third wireless stations And a wireless communication method for performing at least one of the change of the wireless network setting.
- a wireless station wirelessly connected to a wireless terminal, Reception quality of downlink signals from one or more radio stations consisting of at least one of a second radio station of the same type as the radio station and / or a third radio station of a different type from the radio station.
- the type of the wireless station is identified from the report, and at least one of determining whether or not to change the wireless network setting and changing the wireless network setting is executed.
- a radio station comprising means is provided.
- the first wireless station transmits a second wireless station of the same type as the first wireless station and a third wireless device different from the first wireless station to the wireless terminal. Instructing measurement of reception quality of downlink signals from one or more radio stations comprising at least one of the radio stations, receiving a report of measurement results by the radio terminal via the first radio station, Identifying the type of the radio station, determining whether or not it is necessary to change the radio network setting of at least one radio station of the first to third radio stations, and at least one of changing the radio network setting An operation management server device having means for executing is provided.
- the present invention it is possible to perform appropriate optimization processing for each interference factor.
- a radio station radio base station: eNodeB (eNB), base station control station: RNC (Radio Network Controller) and an operation management server (for example, OAM (Operation Administration and Maintenance)) server
- OAM Opera Administration and Maintenance
- At least one of the SONs determines the interference factor (becoming neighboring cell) for the belonging (serving) cell from the information of the measurement report (measurement report) from the wireless terminal (UE: User Equipment). Identification is performed, and at least one of the wireless station and the operation management server executes an optimization process according to the interference factor.
- a wireless network setting for example, (I) Transmit power, antenna tilt angle, System bandwidth, ⁇ Use (carrier) frequency, -Cell selection related parameters, ⁇ Setting wireless parameters such as handover related parameters, (II) Cell type (size and attributes: open, closed, hybrid) Network operation settings, etc. Etc.
- a typical example of a closed cell is a CSG (Closed Subscriber Group) cell of a femto cell (also referred to as a “home cell”).
- CSG Cell Subscriber Group
- home cell a femto cell
- ⁇ Interference from macro base station / cell ⁇ Interference from the micro base station / cell -Interference from the pico base station / cell -Interference from relay base station / cell -Interference from open femto base stations / cells (all wireless terminals can be connected) -Is it interference from a femto base station / cell that is closed (only a limited member (member) can connect), -Interference from hybrid (with both open and closed elements) femto base stations / cells -Interference from base stations / cells (homogeneous or heterogeneous) in the neighbor (white or black) cell list, -Interference from base stations / cells (homogeneous or heterogeneous) outside the neighboring (white or black) cell list, And the like are identified by the radio station and / or the operation management server.
- the interference from the radio base station (radio station) of the macro cell and the interference from the femto base station are identified, and for each interference factor
- the interference from the femto base station is identified as the interference between the macro cell base stations, the coverage is optimized by the increase / decrease of the coverage, and the interference is reduced. Determining and executing at least one method of interference optimization by interference avoidance for. There are several options, as shown below.
- Option 1 When only interference from femto base stations is large, coverage optimization between macro cells and interference optimization are not performed, or interference optimization between macro cells and femto cells has priority over coverage optimization between macro cells. And do it.
- Option 1-1 (Aspect 2): Based on the received power (strength) of each adjacent cell, interference is calculated for each cell type, interference from the macro cell base station is less than a predetermined first predetermined value (predetermined level), and femto If the interference from the base station is greater than or equal to a predetermined second predetermined value (predetermined level), coverage increase / decrease / interference avoidance between macro cells is not performed, or interference optimization between macro cells and femto cells is prioritized. (However, this interference optimization may not be performed.)
- the first and second predetermined values (predetermined levels) may be the same, or may be different values (for example, an offset is set between the first and second predetermined values).
- Option 1-2 A report of measurement results indicating that the interference or reception quality of the interference signal from the macrocell base station is equal to or higher than a predetermined third predetermined value (predetermined level) is a predetermined first predetermined number (predetermined threshold). ) And a report of a measurement result indicating that the reception quality of the interference from the femto base station or the interference signal is equal to or higher than a predetermined fourth predetermined value (predetermined level). If the number is equal to or greater than a predetermined number (predetermined threshold value) of 2, the increase / decrease of coverage between macro cells and avoidance of interference are not performed, or interference optimization between macro cells and femto cells is prioritized (however, this interference optimization) Does not have to be done).
- the third and fourth predetermined values (predetermined level) and the first and second predetermined numbers (predetermined threshold) are the same, but different values (for example, the third and fourth predetermined values). Or an offset is set between the first and second predetermined numbers).
- Option 2 (another aspect): If both the interference from the macro cell base station and the interference from the femto base station are large, • Prioritize macro cell base station coverage increase / decrease and interference avoidance.
- Priority is given to avoiding interference between the macrocell base station and the femto base station.
- Option 3 (another aspect): The present invention is applied to combinations of other cell configurations in which different types of radio base stations / cells interfere with each other, such as between macro cells and pico cells, between micro cells and femto cells, between pico cells and femto cells. Furthermore, the present invention can also be applied to a relay base station (RN). For example, when the type of relay base station / cell is macro, micro, or pico, they are handled in the same manner as the macro base station / cell, micro base station / cell, and pico base station / cell, respectively.
- RN relay base station
- the optimization may be performed by distinguishing the interference from the relay base station / cell.
- the relay base station and the parent base station (DeNB) : Backhaul radio resource setting used for communication between Donor eNode B) may be optimized.
- LTE communication between a relay base station and a parent base station and communication between a relay base station and subordinate radio terminals may be performed in a time-sharing manner, and the time allocated for each communication is set as a backhaul radio resource setting. (Period) setting.
- Option 4 (another aspect): The femto base station / cell type (open, closed, hybrid) is identified and the optimization process is executed. For example, in the case of an interference problem between a macro (or micro, pico) cell and a femto cell, when the femto cell is an “open cell”, the femto base station / cell is replaced with a micro base station / cell or a pico base station / cell. And the above-described coverage optimization and interference avoidance are executed.
- the femtocell is a “closed cell” (also referred to as a “CSG cell” (Closed Subscriber Group cell)) and the interference from the closed femtocell is strong, Interference avoidance may be performed, or the cell type may be changed from closed to open or hybrid, and if the femtocell is a “hybrid cell”, a measurement report (measurement report)
- the interference factor is identified based on the attribute (member or non-member) of the wireless terminal that has performed, and the optimization process of coverage optimization and interference avoidance is executed.
- Option 5 (another aspect): Whether or not the cell is included in the neighbor cell list (NCL) is identified, and interference optimization processing is executed.
- the adjacent cell list is a white list (including a normal adjacent cell list) that is a list of cells to be connected, or a black list (Black list) that is a list of cells to be excluded from the connection target. You may use the method which considers whether there exists. For example, when the cell that causes interference is a cell included in the white list, the above-described coverage optimization and interference avoidance according to the present invention, or coverage optimization and interference avoidance of related technologies are performed.
- coverage optimization and interference avoidance can be performed without considering the measurement report from the wireless terminal regarding the cell (the interference cell not included in the white list).
- the cell it is determined whether or not the cell should be included in the neighbor cell list.
- an ANR function Automatic Neighbor Relation Function for optimization of a neighbor list studied in 3GPP may be used.
- the ANR function has, for example, a function for reporting the presence of neighboring cells that are not recognized by the radio base station to the radio terminal, and can thereby perform automatic optimization of the neighboring cell list.
- the wireless terminal basically does not measure the reception quality of the downlink signal of the blacklist cell.
- the wireless terminal basically does not measure the reception quality of the downlink signal of the blacklist cell.
- the reception quality of the downlink signal of the blacklist cell may be measured. Thereby, the above-described processing can be executed.
- the optimization technique in the present invention is not limited to the above-described coverage optimization and interference avoidance (interference optimization).
- ⁇ Mobile terminal mobility optimization called Mobility Optimization or Mobility Robustness Optimization
- -Load balancing of wireless terminals Load Balancing or Mobility Load Balancing
- Radio (cell) capacity optimization Capacity Optimization
- FIG. 1 is a diagram illustrating a sequence operation of the system according to the first embodiment of this invention.
- radio terminals UE1 to UEn radio terminals UE1 to UEn, macro base stations eNB1 and eNB2, femto base stations HeNB (Femto eNB: also referred to as “FeNB”), and an OAM / SON server are provided.
- HeNB femto base stations
- OAM / SON server OAM / SON server
- the macro base station eNB1 transmits a message (Measurement Configuration) for instructing measurement to the subordinate UE1 to UEn (S1, S2).
- the message (Measurement Configuration) includes measurement items (reception quality, measurement location, measurement timing, etc.), measurement target cell, measurement mode (periodically or when a specific event occurs (event trigger)), measurement report Contents etc. are specified.
- Each of the UE1 to UEn that has received a message (Measurement Configuration) instructing measurement from the base station eNB1 performs measurement according to the content of the instruction (S3, S4: Measurement), and reports the measurement result to the eNB1 (S5, S6: Measurement report).
- ENB1 receives reports of measurement results from UE1 to UEn and reports them to the OAM / SON server (S7: Report).
- the OAM / SON server filters the measurement report (S8: Measurement report filtering), and determines the optimization process for coverage and interference (S9: Optimization process decision).
- the OAM / SON server instructs the eNB1 to adjust radio parameters for coverage optimization and interference avoidance (optimization) (S10: Adjust for optimization).
- ENB1 receives an instruction from the OAM / SON server and performs optimization processing such as coverage optimization and interference optimization (S11: Optimization).
- optimization processing such as coverage optimization and interference optimization (S11: Optimization).
- the OAM / SON server instructs the HeNB and eNB 2 to adjust radio parameters for coverage optimization and interference optimization when necessary (S12, S13: Adjust for optimization).
- the HeNB and eNB2 each receive an instruction from the OAM / SON server and optimize the radio parameters (S14, S15: Optimization).
- the adjustment performed by the eNB or the like is a wireless network setting, and this is not limited to the wireless parameter, and includes the network operation setting as described above.
- FIG. 2 is a block diagram showing the main part of the system configuration related to the present invention in the radio terminal (UE), base station / base station control station, and OAM / SON server in the first embodiment of the present invention. It is. The configuration in FIG. 2 is also applied to each of the second and subsequent embodiments described later.
- the radio terminal 10 receives a measurement instruction acquisition unit 11 that acquires a measurement instruction message transmitted from the base station 20 by radio, receives a measurement instruction from the measurement instruction acquisition unit 11, receives the cell quality, etc. And a measurement result reporting unit 13 for reporting the measurement result to the base station 20 wirelessly.
- the wireless terminal 10 includes a wireless unit and a baseband unit that are not shown.
- a cell detection unit that searches for an appropriate cell such as a cell with good quality for a wireless terminal based on a synchronization signal or the like during communication, standby or intermittent reception (Not shown)
- a control unit (not shown) is provided for line control such as establishment, connection maintenance, and release of a wireless link, management of an idle state / active state, and control of each unit.
- the base station 20 includes a measurement instruction unit 21 that gives a measurement instruction to the wireless terminal 10, a measurement result acquisition unit 22 that receives a measurement instruction from the measurement instruction unit 21, and acquires a measurement result from the wireless terminal 10, and a measurement A measurement result reporting unit 23 for reporting the result to the OAM / SON server 30 and a radio parameter setting changing unit 24 for changing the setting of the base station 20 (tilt angle of transmission antenna, transmission power) are provided.
- the OAM / SON server 30 (operation management server) includes a measurement result acquisition unit 31 that receives a measurement result from the measurement result report unit 23 of the base station 20, and a wireless parameter setting instruction unit 33.
- the radio parameter setting instruction unit 33 issues a radio parameter setting instruction to the base station 20.
- Coverage optimization and interference optimization can be realized by increasing / decreasing (enlarging / reducing) cell coverage, avoiding interference between cells, or both increasing / decreasing cell coverage and avoiding interference between cells.
- the coverage can be increased or decreased in a pseudo manner by adjusting the cell power range by controlling radio parameters (cell individual offset value, event specific offset value, priority, etc.) related to cell selection / handover.
- radio parameters cell individual offset value, event specific offset value, priority, etc.
- Interference avoidance is performed at the radio base station. ⁇ Radio resource usage restrictions, • Execute with transmission power control.
- a use restriction of the radio resource for example, Separate and use time and / or frequency resources between multiple interfering radio base stations, Etc. are used.
- transmission power control for example, Determine the transmission power of data signals based on the amount of interference between radio base stations (limit) Etc. are used.
- a certain radio base station may perform alone or a plurality of radio base stations may perform in cooperation (simultaneously).
- the determination of whether to perform coverage optimization or interference optimization may be performed by the radio base station, or may be performed by an operation management server (OAM / SON server).
- OAM operation management server
- ⁇ Algorithm for coverage optimization / interference optimization> As an example of an algorithm for coverage optimization or interference optimization, a case where attention is paid to a serving cell (assigned cell) of a certain macro cell base station will be described below.
- Step 1 The contents of the measurement report from the wireless terminal are classified and aggregated according to the type of the neighboring cell that is the object of measurement (macro cell, femto cell, etc.) (measurement report filtering). Whether the cell is a macro cell or a femto cell, the cell ID of the measurement target cell included in the report (for example, a physical cell ID (PCI)), or a primary scramble code (ID) for identifying each cell ( PSC)) and the like.
- PCI physical cell ID
- ID primary scramble code
- Step 2 The communication quality (downlink signal reception quality) of the adjacent cell (Reference Signal Received Power: RSRP, Reference Signal Received Quality: RSRQ, etc.) is determined in advance for each type of neighbor cell (such as macro cell or femto cell). Determine whether there are more than a predetermined number of reports (predetermined threshold) (or a predetermined percentage of the total) that are greater than or equal to a predetermined value (predetermined level) If it is greater than or equal to the predetermined number, the optimization process of step 3 is performed, If the number is less than the predetermined number, the process returns to Step 1.
- predetermined threshold a predetermined number of reports
- predetermined level predetermined level
- Step 3 If the neighbor cell type is a macro cell, perform coverage optimization (coverage increase / decrease, cell selection / handover related radio parameter change) When the type of the neighboring cell is a femto cell, macro-femto interference optimization (interference avoidance) is executed.
- coverage optimization coverage increase / decrease, cell selection / handover related radio parameter change
- macro-femto interference optimization interference avoidance
- determining which cell is the target of coverage / interference optimization for example, cells satisfying the condition of Step 2 are biased to a specific neighboring cell pair (combination of serving cell and neighboring cell). Determine whether or not. As a result of the above determination, if there is no bias, coverage / interference optimization is executed only in the serving cell (cell to which the UE belongs). -As a result of the above determination, when it is biased toward a specific neighboring cell pair, coverage / interference optimization is executed for each of the specific neighboring cell pairs.
- FIG. 3 is a flowchart (flow chart) showing the operation of the OAM / SON server according to the first embodiment of the present invention. 3 is performed by the OAM server or the SON server.
- the OAM / SON server receives the measurement report (Step S101: Receive measurement reports).
- the OAM / SON server determines whether the measurement target included in the report is a macro cell or a femto cell (step S102), and records the measurement results separately for the macro cell and the femto cell (steps S103, S104: Store meas results for Macro (Femto) cell). In other words, the OAM / SON server counts the content of the measurement report transmitted from the wireless terminal via the wireless base station according to the type of the neighboring cell that is the measurement target (whether it is a macro cell or a femto cell).
- step S105 Y of Any Optimization for Macro
- step S106 Indication adjustment
- the OAM / SON server determines that the femto cell optimization is necessary (S107: Y of Any Optimization for Femto), it instructs the femto base station HeNB to adjust the optimization (step S108: Indicate). adjustment for optimization to HeNB).
- FIG. 4 is a diagram for explaining a first modification of the first embodiment of the present invention.
- the sequence from S1 to S6 is the same as that in FIG.
- ENB1 upon receiving measurement reports from UE1 to UEn, performs measurement report filtering (macro cell or femto cell, etc.), and classifies the report according to macro cell and femto cell reports (S8 ': Measurement report filtering).
- ENB1 transmits the classified report to the OAM / SON server (S7: Report).
- the OAM / SON server determines the coverage / interference optimization process (S9: Optimization process decision).
- the OAM / SON server instructs the eNB 1 to adjust radio parameters for coverage / interference optimization (S10: Adjust for optimization).
- ENB1 receives an instruction from the OAM / SON server and optimizes the radio parameter (S11: Optimization).
- the OAM / SON server instructs the HeNB and eNB 2 to adjust radio parameters for coverage / interference optimization, if necessary (S12, S13: Adjust for optimization).
- Each of the HeNB and eNB2 receives an instruction from the OAM / SON server and optimizes radio parameters (S14, S15: Optimization). Note that the adjustment for optimization is not limited to the wireless parameter, and may be any of the wireless network settings.
- FIG. 5 is a diagram illustrating a second modification of the first embodiment of the present invention.
- the sequence from S1 to S6 is the same as in FIG.
- eNB1 Upon receiving the measurement reports from UE1 to UEn, eNB1 performs measurement report filtering (macro cell or femto cell, etc.) and classifies the macro cell and the femto cell according to the report (S8 ′: Measurement report filtering), Coverage / interference optimization processing is determined (S9 ′: Optimization process decision), the own cell is optimized (S11 ′: Optimization), and an optimization execution report is transmitted to the OAM / SON server (S7 ′). : Optimization execution report).
- measurement report filtering macro cell or femto cell, etc.
- the OAM / SON server determines an optimization process in the neighboring cell (S9 ′′). When the optimization process is necessary, the OAM / SON server performs coverage / interference with respect to the HeNB and the eNB 2 respectively. Instructs adjustment of radio parameters for optimization (S12, S13: Adjust for optimization) HeNB and eNB2 receive instructions from the AM / SON server and optimize radio parameters (S14, S15: Optimization) It should be noted that the object to be adjusted for optimization is not limited to the wireless parameter, and may be either a wireless parameter or a wireless network setting.
- FIG. 6 is a diagram for explaining a second embodiment of the present invention.
- interference is calculated for each cell type based on the received power (RSRP) of each neighboring cell, and the interference from the femto base station is equal to or greater than a predetermined second predetermined value (level).
- RSRP received power
- level a predetermined second predetermined value
- the interference from the macro cell base station is less than a first predetermined value (level) determined in advance, coverage optimization between macro cells (coverage increase / decrease, radio parameter change such as cell selection / handover related parameters), interference No optimization (interference reduction / avoidance) is performed.
- the first and second predetermined values may be the same, or an offset may be set between the first and second predetermined values.
- an optimization procedure viewed from the macro cell viewpoint is shown below.
- the received power RSRP of the downlink reference signal (pilot signal) of the macro cell of the serving cell of the wireless terminal that performed the measurement report, and the received power RSRP of the downlink reference signal (pilot signal) for each adjacent cell are tabulated.
- the counting results may be averaged every predetermined period, or may be reset every time the optimization process is performed.
- interference Interference Signal Strength Indicator: referred to as interference signal strength index or interference wave power
- interference may be averaged at predetermined intervals.
- a known method is used to calculate RSRP and ISSI of the LTE downlink reference signal (common pilot signal).
- Coverage between macro cells when interference from adjacent cells that are femto cells is greater than or equal to a predetermined second predetermined value, but interference from adjacent cells that are macro cells is less than a predetermined first predetermined value Does not perform optimization such as optimization and interference optimization.
- interference such as ISSI
- ISSI received power
- the interference (ISSI) from the base stations eNB2 and eNB3 of the macrocell Cell2 and Cell3 is predetermined.
- coverage increase / decrease and interference avoidance between macro cells are not performed.
- the interference (ISSI) from the base stations eNB2 and eNB3 of the macrocells Cell2 and Cell3 is equal to or greater than a predetermined value, coverage increase / decrease and interference avoidance between the macrocells are performed.
- a report that the reception quality of the interference signal from the femto base station is equal to or higher than a predetermined value a report that the reception quality is less than a predetermined value due to interference from the femto base station is sent from the macro base station.
- a report indicating that the reception quality of the interference signal is equal to or higher than a predetermined value a report whose reception quality is less than a predetermined value due to interference from the macro base station may be used.
- FIGS. 7A and 7B are diagrams illustrating a third embodiment of the present invention.
- FIG. 7A is a diagram schematically showing an example of the management table in the present embodiment, and corresponds to the cell configuration of FIG. 7B.
- the source cell is the macro cell Cell1
- the counters of the macro cells Cell2, Cell3, the femtocell Cell01, and Cell02 are set as the neighboring cells.
- the source cell is the macro cell Cell2
- the counters of the adjacent macro cells Cell1, Cell3, femtocell Cell01, Cell02 are set.
- the source cell is the macro cell Cell3, counters of the neighboring macro cells Cell1, Cell2, femtocell Cell01, Cell02 are set.
- a counter may be set as a source of the femtocell.
- the counter of the equal cell (the number of reports of the equal cell) is incremented. For example, in the source cell Cell1, when the number of reports that the reception quality of the interference signal from the adjacent macrocell Cell2 is equal to or higher than a predetermined value is reported, the value of the counter Nm12 in FIG.
- the wireless terminal which is defined in the specification of Non-Patent Document 5
- the wireless terminal is measured during the idle state (IDLE mode), and the measurement result is transmitted to the wireless network during the active (Active) state.
- a method of reporting (Logged MDT (Minimization Drive Test)) is assumed.
- a method (Immediate MDT) that is defined in the specification of Non-Patent Document 5 and causes a wireless terminal to perform measurement and report a measurement result while the wireless terminal is in an active state is described above. It is applicable to the embodiment.
- the idle state refers to a state in which the radio terminal (UE) is in a power-on state such as a standby state, but has not established a radio resource control (RRC) connection (non-patent).
- RRC radio resource control
- Reference 8 Instructs RRC_IDLE (Radio Resource Control IDLE; Radio Resource Control Idle) in LTE and Idle (UTRAN IDLE) in UMTS (Universal Mobile Telecommunications System).
- the wireless terminal (UE) when the wireless terminal (UE) is in an idle state, which cell the wireless terminal (UE) is in is not managed on the wireless network side, and which tracking area (Tracking Area: TA), location Whether it belongs to an area (Location Area: LA) or a routing area (Routing Area: RA) is managed on the wireless network side.
- the tracking area is managed by MME (Mobility Management Entity) or the like.
- Active state indicates RRC_CONNECTED in LTE and CELL_DCH in UMTS.
- CELL_DCH is an RRC state in which a dedicated physical channel is allocated to a radio terminal (UE) in uplink and downlink, and the radio terminal (UE) and the radio base station are connected by a dedicated channel to perform transmission / reception.
- the content measured by the radio terminal (UE) in an idle state includes: -Reception quality of the downlink pilot signal (reference signal) of the belonging cell (Serving cell), -Reception quality of downlink pilot signals (reference signals) of neighboring (adjacent) cells (Neighboring cells), Etc. That is, the radio terminal (UE) measures the reception quality of the downlink reference signal (pilot signal) from the base station of the cell.
- the reception quality is RSRP (Reference Signal Received Power: received power of a desired downlink reference signal), RSRQ (Reference Signal Received Quality: value obtained by dividing the received power of the desired downlink reference signal by the total received power of the downlink) Etc. are used.
- RSSI is the total received power of the wireless terminal.
- the content reported by the radio terminal (UE) to the radio network side is: ⁇ Identification (serving) cell identifier (ECGI: E-UTRAN Cell Global Identifier) and reception quality of downlink pilot signal (RSRP, RSRQ), ⁇ Reception quality of downlink pilot signals of neighboring (adjacent) cells, Measurement time (relative time from the time when the radio terminal (UE) received the measurement instruction), ⁇ Position information (valid GNSS (Global Navigation Satellite System) position information held at the time of measurement) Etc.
- GNSS Global Navigation Satellite System
- the wireless terminal does not have valid GNSS location information, instead of GNSS location information as its location information, PCI (Physical Cell Identifier) / PSC (Primary Scrambling Code) + RSRP / CPICH Common Pilot Channel Received Signal Code Power (peripheral cell neighbor signal quality) )
- E- UTRAN radio base station / base station control station ((e) NodeB / RNC) performs measurement in an idle state and records measurement results (logging) to an active radio terminal (UE). Instruct to run. That is, the wireless network transmits an idle MDT configuration message to the wireless terminal (UE) in order to transfer a configuration parameter of the Logged MDT performed in the idle state (Idle mode). Start the Logged MDT procedure.
- the radio terminal After transitioning from the active state to the idle state, the radio terminal (UE) performs measurement and logging in the idle state in accordance with an instruction from the radio network ((E-) UTRAN).
- the cell to be measured is basically the same as a normal idle UE. That is, the measurement by Logged MDT follows the principle of idle mode measurement of a radio terminal (UE) defined in 3GPP TS 25.133, TS 36.133, and the like.
- Non-patent document 6 When a wireless terminal (UE) stays in the coverage hole, instead of logging the measurement result of the belonging cell (neighbor cell) and the neighboring cell (neighbor cell), logging with “Out Of Service” (OOS) (out of service area) (Non-patent document 6).
- OOS Out Of Service
- MDT measurement and logging are continued only during a specific period (for example, while the terminal is in the “camped normally” state).
- Suspend MDT measurement and logging when the terminal stays in the coverage hall even after a certain period of time has elapsed for example, while the terminal is in the “any cell selection” or “camped on any cell” state).
- Has also been examined (Non-patent Document 5). In addition, it returns to "camped normally” state again, and when Idle MDT Configuration is effective at that time, MDT measurement and Logging are restarted.
- the coverage hole refers to the belonging cell (serving cell) and a predetermined service such as a normal service (calling, incoming call, user data transmission / reception, etc.) (“connection”, SNR (Signal to Noise Ratio: Signal to Noise Ratio) or SINR (Signal to Interference and Noise Ratio: Signal to Interference Noise Ratio) of neighboring cells that are allowed to establish wireless links)
- the predetermined value required to maintain the basic service (establishing SRB (Signaling Radio Bearer: Signaling Radio Bearer) and acquiring information sent on DL common channels) It refers to are turning area.
- the SRB is a bearer for carrying an RRC (Radio Resource Control) message that is a control message.
- RRC Radio Resource Control
- the wireless terminal determines that it is a coverage hole, for example, ⁇ When a cell allowed to belong during “camped normally” state could not be selected (broadcast information could not be acquired), ⁇ If it was not possible to select a cell that was allowed to belong during the “any cell selection” state, ⁇ If a cell allowed to belong during “camped on any cell” state could not be selected, Etc. In this specification, as an example, it is assumed that a cell that is allowed to belong during “camped normally” state cannot be selected as a coverage hole.
- a radio terminal (UE) set to Logged MDT performs measurement in an idle state, and reports a measurement result when it enters an active state.
- a radio terminal (UE) configured from the radio network side to execute Logged MDT in an idle state, for example, 1 in an RRC connection complete (RRC_CONNECTION Setup Complete) message when establishing an RRC connection when transitioning to the RRC_CONNECTED state.
- RRC_CONNECTION Setup Complete RRC connection complete
- a bit is used to indicate that the MDT measurement result is available (has a log). Based on this instruction, the wireless network searches (collects) logs.
- the E-UTRAN radio base station transmits a radio terminal (UE) information request (UE Information Request) to the radio terminal (UE) for log search (collection), and the radio terminal (UE) The log is reported as a UE information response (UE Information Response).
- UE Information Request radio terminal information request
- UE Information Response UE information response
- the search (collection) of the log (measurement result) held by the wireless terminal (UE) from the network is reported (collected, and the retained log (measurement result) is reported from the wireless terminal. This is called (Log retryval).
- FIG. 8 is a diagram for explaining the sequence operation of the fourth embodiment of the present invention.
- eNB1 measures and records (logs) the reception quality in the idle state for UE1 to UEn in the active state (RRC_CONNECTED) in the Logged MDT configuration message. An instruction is given to report the log (S20, S21).
- UE1 to UEn enter an idle state (S22, S24: Go to Idle), and perform measurement and logging of belonging (serving) cells and neighboring cells (S23, S25: Measurement and logging).
- UE1 detects a deterioration in reception quality of the serving cell base station eNB1 and detects that the stay area is a coverage hole (S26: Coverage hole detection).
- S26 Coverage hole detection
- UE1 may or may not perform measurement of cells of eNB1 and eNB2.
- measurement of a HeNB cell may also be performed. These measurements may be performed voluntarily by UE1 to UEn, or may be performed by issuing an instruction to UE1 to UEn with a Logged MDT configuration message. Furthermore, you may instruct
- measurement of the cells of eNB1, eNB2, and HeNB may be performed during a predetermined period until coverage hole detection, and the measurement may be interrupted after the predetermined period (that is, after coverage hole detection).
- UE1 shall detect an appropriate cell (S27: Find suiteable cell) (Here, eNB1 shall be detected.).
- S27 Find suiteable cell
- eNB1 shall be detected.
- a well-known method is used for the cell detection method in UE (nonpatent literature 7).
- UE1 to UEn each establish a radio link (RRC Connection) with eNB1, become active (S28, S29: Go to Active), and report the measurement results to base station eNB1 (S30, S31: Measurement retrieval respectively).
- RRC Connection radio link
- ENB1 reports the measurement results respectively reported from UE1 to UE to the OAM / SON server (S32: Report).
- the OAM / SON server performs a filtering process for classifying the measurement report into a macro cell, a femto cell, etc. (S33: Measurement report filtering).
- the OAM / SON server determines optimization processing such as coverage optimization between macro cells, interference optimization, and interference optimization between macro-femto cells (S34: Optimization process decision).
- the OAM / SON server instructs the eNB 1 to make adjustments for optimization (S35: Adjust for optimization).
- the eNB 1 receives an adjustment instruction for the optimization, adjusts radio network settings (settings of radio parameters and network operation parameters), and performs coverage optimization, interference optimization, and the like (S36: Optimization).
- UE1 When UE1 detects a coverage hole in the macro cell of eNB1, if interference from the base station HeNB of the femtocell that is a neighboring cell is a factor of the coverage hole, interference between macro-femto instead of reducing the cell size Perform optimization. Thereby, the coverage of a macro cell can be reduced unnecessarily, and a coverage hole (dead zone) can be prevented from being generated.
- FIG. 9 is a diagram for explaining another example of coverage optimization and interference optimization (an example different from the algorithm described above). With reference to FIG. 9, another example of coverage optimization and interference optimization will be described.
- the macro cell base stations UEa and UEb transmit measurement reports to the eNB1 and eNB3, respectively (1a, 1b: Meas report).
- UEa receives interference from neighboring cells Cell2 and Cell3 and interference from femtocells in cell Cell1, and inter alia, interference from femtocells is dominant.
- the UEb receives interference from the adjacent macro cells Cell1 and Cell2, and in particular, interference from the macrocell Cell2 is dominant.
- the OAM / SON server determines a countermeasure for the optimization based on the information of the measurement report from each eNB (2a: Report).
- the OAM / SON server does not change the radio parameters for Cell1 coverage optimization.
- the OAM / SON server changes the setting of the radio parameter of the base station of the Cell3 to optimize the coverage. Plan For example, in order to reduce interference from Cell2, the coverage of Cell3 is reduced (4b: Shrink coverage of Cell1).
- the eNB1 When the eNB1 receives many reports that the interference of the femtocell is dominant like the UEa, the interference between the Cell1 and / or the cell Cell1 of the HeNB and the femtocell is optimized. Alternatively, femtocell coverage optimization may be performed.
- the OAM / SON server may issue an interference optimization instruction to the eNB 1 so that the eNB 1 alone or in cooperation with the HeNB executes the interference avoidance technique, or The OAM / SON server may issue an instruction to both the eNB 1 and the HeNB to execute the interference avoidance technique.
- a radio resource used by the eNB 1 in the macro cell Cell 1 and a radio resource (time, frequency, code, etc.) used by the HeNB in the femto cell are separated.
- the subframe used in Cell1 is divided from the subframe used in femtocell.
- the usage restriction may be provided only on the femtocell side.
- no usage restriction is provided on the subframe, and usage restriction is provided only on Cell1 side. May be.
- the frequency band used by the HeNB in the femto cell may be narrowed down.
- the frequency band of the femto cell is reduced to a half on the high frequency side.
- the frequency band may be limited to the system band itself, or only the band for data transmission (in this case, the common control signal and the like are transmitted in the same band as before the frequency is reduced).
- the maximum transmission power set by the eNB 1 in the Cell 1 and / or the maximum transmission power set by the HeNB in the femto cell is reduced.
- the reduction of the maximum transmission power may be performed for both the reference signal and data, or only the reference signal or data only.
- HetNet heterogeneous network
- the neighboring cell is determined to be macro / micro / pico / H (e) NB by PCI / PSC.
- CSG cell (H (e) NB) When CSG cell (H (e) NB) is mixed (CSG cell is included in Black list), or any CSG cell is not a member but a neighboring cell is not a member. If it can be determined as a CSG cell), the RSRQ of the belonging (serving) cell is lower than a predetermined threshold value, and the maximum (or the top Nth) RSRP of the neighboring cell is lower than a predetermined threshold value, It is determined that there is a non-member (non-member) CSG cell that has strong interference in the vicinity.
- the black list is a list that prevents the wireless terminal (UE) from performing measurement (quality measurement) of a specific neighboring cell.
- a CSG cell restricts access to a specific group such as a femtocell owner or family.
- wireless terminal identifies the kind of adjacent cell, and reports a measurement and a measurement result.
- coverage mapping also referred to as “coverage mapping”.
- the measurement target or measurement result is identified on the radio terminal (UE) side, and measurement and / or measurement result reporting is performed.
- UE radio terminal
- measurement and / or measurement result reporting is performed.
- the type of cell (macrocell / micro / pico or femtocell (open, closed, hybrid) in a heterogeneous network (HetNet), or ⁇ A cell in the neighboring cell list, a cell outside the neighboring cell list, or a cell in the black list) Etc. may be used.
- the radio base station (eNB) (or base station control station: RNC) instructs the radio terminal (UE) to perform measurement and / or report of a measurement result on a specific type of cell.
- the radio terminal When the measurement and the report of the measurement result are performed for a specific type of cell, the radio terminal (UE), in accordance with the instruction, of the belonging (serving) cell and the neighboring (adjacent) cell of the type specified by the instruction The reception quality is measured, and the measurement result is reported to the radio base station (eNB).
- eNB radio base station
- the radio terminal When only the measurement result for a specific type of cell is reported, the radio terminal (UE) performs measurement of the reception quality of the serving cell and the neighboring cell, regardless of the cell type, and the measurement result At the time of reporting, it is determined whether or not it is a specific type of cell to be reported, and only relevant measurement results are reported. This avoids (reduces) the use of uplink radio resources for reporting unnecessary (low necessity) measurement results by the wireless terminal, and performs unnecessary (low necessity) measurement and / or Alternatively, battery consumption due to reporting of measurement results can be avoided (reduced). Furthermore, it is possible to efficiently collect necessary measurement results on the wireless network side.
- Hetogeneous Network HetNet
- the wireless terminal is not a member of any CSG cell and if it can be determined whether it is a CSG cell by PCI / PSC, it is a CSG cell (in this case, non-member) by the detected PCI / PSC. It is determined whether or not.
- H (e) NB Mixed CSG cells (when the CSG cell is in the black list, or any CSG cell is not a member but a neighboring cell is not a member by PCI / PSC) If it can be determined as a CSG cell), The RSRQ of the belonging (serving) cell is lower than a predetermined threshold value, -In addition, when the maximum (or the top N-th) RSRP of neighboring cells is lower than a predetermined threshold value, It is determined that there is a non-member CSG cell that causes strong interference in the vicinity. In this method, the interference (reception quality) of the CSG cell is not measured and reported, but instead it may be notified that “there is a CSG cell that causes strong interference”.
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Abstract
Description
本発明は、日本国特許出願:特願2010-224389号(2010年10月01日出願)の優先権主張に基づくものであり、同出願の全記載内容は引用をもって本書に組み込み記載されているものとする。
・無線基地局(eNodeB又はeNB:evolved Node B or enhanced Node B、あるいは単に「基地局」とも略記される)の送信電力、
・無線基地局のアンテナチルト角、
・隣接セル情報、
・ハンドオーバ・パラメータ
等があり、上述のような目的を達成するように、無線基地局や運用管理サーバ(OAM(Operation Administration and Maintenance)server、又は、SON server)にて、これら無線パラメータの一つ又は複数を適宜変更する。
R=(Ec/Ioが閾値を超えた端末の比率)
を算出する。算出したRが目標値(Target)よりも大の場合、基地局あるいはOAMは、無線基地局の送信電力を単位ステップダウンさせる。Rが目標値(Target)よりも小の場合、基地局あるいはOAMは、無線基地局の送信電力を単位ステップアップさせる。なお、LTEでは、Ec/Ioの代わりに、RSRQ(Reference Signal Received Quality)が用いられることが考えられる。
前記第1の無線局は、前記無線端末に対して1つ以上の前記第2又は前記第3の無線局からの下り信号の受信品質の測定を指示し、
前記無線端末は、前記指示に従い測定を行う測定部を有し、
前記第1の無線局及び前記運用管理サーバの少なくとも1つが、前記無線端末による測定結果の報告を受け、前記報告から前記無線局の種類を識別して、前記第1乃至第3の無線局の少なくとも1つの無線局の無線ネットワーク設定の変更の要否の判断、及び、前記無線ネットワーク設定の変更の少なくとも1つを実行する手段を備えた無線通信システムが提供される。
前記無線端末は前記指示に従い測定を行い、
前記第1の無線局及び運用管理サーバの少なくとも1つにより、
前記無線端末による測定結果の報告を受け、前記報告から前記無線局の種類を識別して、前記第1乃至第3の無線局の少なくとも1つの無線局の無線ネットワーク設定の変更の要否の判断、及び、前記無線ネットワーク設定の変更の少なくとも1つを実行する、無線通信方法が提供される。
前記無線端末に対して、前記無線局と同種の第2の無線局及び/又は前記無線局と異種の第3の無線局の少なくとも一方からなる1つ以上の無線局からの下り信号の受信品質の測定を指示し、
前記無線端末による測定結果の報告を受け、前記報告から前記無線局の種類を識別して、無線ネットワーク設定の変更の要否の判断、及び、前記無線ネットワーク設定の変更の少なくとも1つを実行する手段を備えた無線局が提供される。
(I)送信電力やアンテナチルト角、
・システム帯域幅、
・使用(キャリア)周波数、
・セル選択関連パラメータ、
・ハンドオーバ関連パラメータ
等の無線パラメータの設定や、
(II)セルの種類(サイズや属性:オープン、クローズド、ハイブリット)
等のネットワーク運用設定、
等が挙げられる。
・マクロ基地局/セルからの干渉であるか、
・マイクロ基地局/セルからの干渉であるか、
・ピコ基地局/セルからの干渉であるか、
・中継基地局/セルからの干渉であるか、
・オープン(全無線端末が接続可能)なフェムト基地局/セルからの干渉であるか、
・クローズド(限られた会員(メンバー)のみ接続可能)なフェムト基地局/セルからの干渉であるか、
・ハイブリッドな(オープンとクローズドの両要素を持つ)フェムト基地局/セルからの干渉であるか、
・隣接(ホワイト或いはブラック)セルリスト内の(同種又は異種の)基地局/セルからの干渉であるか、
・隣接(ホワイト或いはブラック)セルリスト外の(同種又は異種の)基地局/セルからの干渉であるか、
等の違いの識別が、無線局及び/又は運用管理サーバで行われる。
フェムト基地局からの干渉のみが大きい場合には、マクロセル間のカバレッジ最適化や干渉最適化を行わない、あるいは、マクロセル‐フェムトセル間の干渉最適化を、マクロセル間のカバレッジ最適化よりも、優先して行う。
各隣接セルの受信電力(強度)を基に、セルの種類毎に干渉を算出し、マクロセル基地局からの干渉が予め定められた第1の所定値(所定レベル)未満であり、且つ、フェムト基地局からの干渉が予め定められた第2の所定値(所定レベル)以上である場合、マクロセル間のカバレッジ増減・干渉回避は行わないか、又は、マクロセル‐フェムトセル間の干渉最適化を優先して行う(但し、この干渉最適化は行わなくても良い)。なお、第1と第2の所定値(所定レベル)は同じであってもよく、互いに異なる値(例えば、第1、第2の所定値の間にオフセットを設定)であっていてもよい。
マクロセル基地局からの干渉又は干渉信号の受信品質が予め定められた第3の所定値(所定レベル)以上であることを示す測定結果の報告が、予め定められた第1の所定数(所定閾値)未満であり、且つ、フェムト基地局からの干渉又は干渉信号の受信品質が予め定められた第4の所定値(所定レベル)以上であることを示す測定結果の報告が、予め定められた第2の所定数(所定閾値)以上である場合には、マクロセル間のカバレッジ増減・干渉回避は行わないか、又は、マクロセル‐フェムトセル間の干渉最適化を優先して行う(但し、この干渉最適化は行わなくても良い)。なお、第3と第4の所定値(所定レベル)、第1と第2の所定数(所定閾値)はそれぞれ同じであっても、互いに異なる値(例えば、第3と第4の所定値の間、第1と第2の所定数の間、それぞれにオフセットを設定)であってもよい。
マクロセル基地局からの干渉とフェムト基地局からの干渉が共に大きい場合、
・マクロセル基地局のカバレッジ増減・干渉回避を優先して実行する。
マクロセル・ピコセル間、マイクロセル・フェムトセル間、ピコセル・フェムトセル間等、干渉し合う無線基地局/セルが異なる種類である他のセル形態の組み合わせに適用する。さらに、中継基地局(Relay Node:RN)の場合にも適用可能である。例えば、中継基地局/セルの種類がマクロ、マイクロ、ピコである場合、それぞれマクロ基地局/セル、マイクロ基地局/セル、ピコ基地局/セルと同様に扱う。
フェムト基地局/セルの種類(オープン、クローズド、ハイブリッド)まで識別し、最適化処理を実行する。例えば、マクロ(又は、マイクロ、ピコ)セルとフェムトセルの干渉問題において、フェムトセルが“オープン(Open)セル”の場合、フェムト基地局/セルを、マイクロ基地局/セルやピコ基地局/セルと同様の扱いとし、前述のようなカバレッジ最適化や干渉回避を実行する。
隣接セルリスト(Neighbour Cell List:NCL)に含まれるセルであるか否かを識別し、干渉最適化処理を実行する。このとき、隣接セルリストが接続対象となるセルのリストであるホワイトリスト(White List)か(通常の隣接セルリストを含む)、接続対象から除外するセルのリストであるブラックリスト(Black list)であるかを考慮する方法を用いてもよい。例えば、干渉となるセルがホワイトリストに含まれるセルの場合、上述した本発明によるカバレッジ最適化や干渉回避、あるいは、関連技術のカバレッジ最適化や干渉回避を行う。
・無線端末の移動性最適化(Mobility Optimization、又は、Mobility Robustness Optimizationと呼ばれる)、
・無線端末の負荷分散(Load Balancing、又は、Mobility Load Balancing)、
・無線(セル)容量最適化(Capacity Optimization)、
等、他のSON技術の実行判定にも適用可能である。
図1は、本発明の第1の実施形態のシステムのシーケンス動作を説明する図である。図1に示すように、無線端末UE1~UEnと、マクロ基地局eNB1、eNB2、フェムト基地局HeNB(Femto eNB:「FeNB」とも呼ぶ)、OAM/SONサーバを備えている。
図2は、本発明の第1の実施形態における無線端末(UE)、基地局/基地局制御局、OAM/SONサーバにおいて、本発明に関連するシステム構成の要部をブロック構成にて示す図である。なお、図2の構成は、後述する第2の実施形態以降の各実施形態にも適用される。図2を参照すると、無線端末10は、基地局20から無線により送信される測定指示のメッセージを取得する測定指示取得部11と、測定指示取得部11からの測定指示を受け、セルの品質等を測定する測定実施部12と、測定結果を基地局20に無線で報告する測定結果報告部13を備えている。無線端末10には、図示されない無線部、ベースバンド部を備えている。
無線リンクの接続確立、接続維持、解放等の回線制御、さらに、アイドル状態/アクティブ状態の管理、各部の制御を行う制御部(不図示)を備えている。
・下りリファレンス信号(パイロット信号)等の送信電力の増減、
・アンテナチルト角の増減
等により行われる。
・無線リソースの使用制限、
・送信電力制御
等で実行する。
干渉し合う複数の無線基地局間で時間及び/又は周波数リソースを分けて使用する、
等の手法が用いられる。
無線基地局間での干渉量を基に、データ信号の送信電力を決定する(制限をする)
等の手法が用いられる。
カバレッジ最適化や干渉最適化のアルゴリズムの例として、あるマクロセル基地局のあるサービングセル(帰属セル)に注目した場合を以下に説明する。
無線端末からの測定報告(measurement report)の内容を、測定の対象となった隣接セルの種類別に分類して集計する(マクロセルか、フェムトセルか、等)(measurement report filtering)。マクロセルか、フェムトセルか等は、報告に含まれる測定対象セルのセルID(例えば、セルの物理セルID(PCI:Physical Cell ID)、又は、各セルを識別するためのプライマリ・スクランブル・コード(PSC))等で判別される。
隣接セルの種類(マクロセルか、フェムトセルか等)別に、隣接セルの通信路品質(下り信号の受信品質)(Reference Signal Received Power:RSRPや、Reference Signal Received Quality:RSRQ等)が予め定められた所定値(所定レベル)以上である報告が、予め定められた所定数(所定閾値)(又は全体に対して所定割合)以上あるか否かを判定し、
前記所定数以上の場合、ステップ3の最適化処理を行い、
前記所定数未満の場合、ステップ1に戻る。
隣接セルの種類がマクロセルである場合には、カバレッジ最適化(カバレッジ増減、セル選択・ハンドオーバ関連の無線パラメータ変更)を実行し、
隣接セルの種類がフェムトセルである場合には、マクロ-フェムト間の干渉最適化(干渉回避)を実行する。
・上記判定の結果、偏りがない場合、サービングセル(UEが帰属するセル)のみで、カバレッジ・干渉最適化を実行する。
・上記判定の結果、特定の隣接セルペアに偏っている場合、当該特定の隣接セルペアのそれぞれでカバレッジ・干渉最適化を実行する。
図4は、本発明の第1の実施形態の変形例1を説明する図である。なお、図4において、S1からS6のシーケンスは、図1と同一であるため、説明を省略する。
図5は、本発明の第1の実施形態の変形例2を説明する図である。図5において、S1からS6のシーケンスは、図1と同一であるため、説明を省略する。
本発明の第2の実施形態を説明する。図6は、本発明の第2の実施形態を説明する図である。本実施形態では、各隣接セルの受信電力(RSRP)を基に、セルの種類毎に干渉を算出し、フェムト基地局からの干渉は予め定められた第2の所定値(レベル)以上であるが、マクロセル基地局からの干渉が予め定められた第1の所定値(レベル)未満である場合、マクロセル間のカバレッジ最適化(カバレッジ増減、セル選択・ハンドオーバ関連パラメータ等の無線パラメータ変更)、干渉最適化(干渉低減・回避)は行わない。第1、第2の所定値は同じでも良いし、第1、第2の所定値の間にオフセットを設定してもよい。例として、マクロセルの観点から見た最適化の手順について以下に示す。
次に本発明の第3の実施形態を説明する。本実施形態では、フェムト基地局からの干渉信号の受信品質が予め定められた所定値以上である報告が、予め定められた所定数以上あり、且つ、マクロ基地局からの干渉信号の受信品質が予め定められた所定値以上である報告が、前記所定数未満である場合には、マクロセル間のカバレッジ増減・干渉回避は行わない。なお、所定期間内の同一無線端末からの報告は1つの報告として扱う。また、フェムト基地局からの干渉信号の受信品質が所定値以上である報告の代わりに、フェムト基地局からの干渉により受信品質が予め定められた所定値未満である報告を、マクロ基地局からの干渉信号の受信品質が所定値以上である報告の代わりに、マクロ基地局からの干渉により受信品質が予め定められた所定値未満である報告を、それぞれ用いても良い。
本発明の第4の実施形態について説明する。本実施形態では、非特許文献5の仕様に規定されている、無線端末(UE)がアイドル状態(IDLE mode)の間に測定させ、アクティブ(Active)状態の間に、無線ネットワークに測定結果を報告させる方式(Logged MDT(Minimization Drive Test))を想定する。なお、同様に非特許文献5の仕様に規定されている、無線端末がアクティブ(Active)状態の間に、無線端末に測定および測定結果の報告を行わせる方式(Immediate MDT)については、上述の実施形態に適応可能である。
・帰属セル(Serving cell)の下りパイロット信号(リファレンス信号)の受信品質、
・周辺(隣接)セル(Neighbouring cell)の下りパイロット信号(リファレンス信号)の受信品質、
等がある。すなわち、無線端末(UE)は、上記セルの基地局からの下りリファレンス信号(パイロット信号)の受信品質を測定する。なお、LTEでは、受信品質として、
・RSRP(Reference Signal Received Power:下りリンクの希望リファレンス信号の受信電力)、
・RSRQ(Reference Signal Received Quality:下りリンクの希望リファレンス信号の受信電力を下りリンクの全受信電力で割った値)
等が用いられる。RSSIは無線端末の全体の受信電力である。
・帰属(サービング)セルの識別子(ECGI:E-UTRAN Cell Global Identifier)および下りパイロット信号の受信品質(RSRP、RSRQ)、
・周辺(隣接)セルの下りパイロット信号の受信品質、
・測定時刻(無線端末(UE)が測定指示を受けた時刻からの相対時刻)、
・位置情報(測定時に保有していた有効なGNSS(Global Navigation Satellite System:全地球航法衛星システム)位置情報)
等がある。ここで、無線端末での測定時刻が、当該無線端末でのGNSS位置情報の取得時刻から予め定められた所定時間以内である場合に、無線端末は、該GNSS位置情報が「有効」であるものと判定する。無線端末(UE)が有効なGNSS位置情報を保有していない場合には、その位置情報として、GNSS位置情報の代わりに、
PCI(Physical Cell Identifier)/PSC(Primayr Scrambling Code)+RSRP/CPICH RSCP(Common Pilot Channel Received Signal Code Power)(周辺(隣接)セルの物理セル特定情報+周辺(隣接)セルの下りパイロット信号の受信品質)を報告する。
・隣接セルリスト(Neighbour cell list)に含まれるセルと、
・UEが検出した隣接セルリスト以外のセル(detected cell)
である。
・“camped normally” stateの間に帰属を許可されたセルを選択できなかった(報知情報を取得できなかった)場合、
・“any cell selection” stateの間に帰属を許可されたセルを選択できなかった場合、
・“camped on any cell” stateの間に帰属を許可されたセルを選択できなかった場合、
等が挙げられる。本明細書では、例として、“camped normally” stateの間に帰属を許可されたセルを選択できなかった場合にカバレッジホールと判定するものとする。
図9は、カバレッジ最適化や干渉最適化の別の例(前述したアルゴリズムとは異なる例)を説明する図である。図9を参照して、カバレッジ最適化や干渉最適化の別の例を説明する。
・OAM/SONサーバが、eNB1に干渉最適化の指示を出し、eNB1が自身だけ又はHeNBと協調して、干渉回避技術を実行するようにしても良いし、あるいは、
・OAM/SONサーバが、eNB1とHeNBの両方に指示を出し、それぞれ干渉回避技術を実行するようにしても良い。
ヘテロジニアスネットワーク(Heterogeneous Network:HetNet)における隣接セルの種類の識別例について説明する。
次に本発明の第5の実施形態について説明する。本実施形態では、無線端末(UE)が隣接セルの種類を識別し、測定や測定結果の報告を行う。背景には、無線ネットワーク側で、カバレッジの把握(「Coverage mapping」とも呼ぶ)を行う為には、無線端末(UE)からできるだけ多くの測定報告を収集することが望まれる。しかしながら、無線端末(UE)からの測定報告を増大させると、測定報告の為の無線端末(UE)から基地局eNBへの上りのメッセージ(シグナリング)が増加し、上りデータ送信に使用できる無線リソースが減少してしまう、という問題がある。また、無線端末(UE)としては、多くの測定および測定報告を行うことで、バッテリ消費量が増大する、という問題もある。さらに、無線ネットワーク側から見て、無線端末(UE)からの測定報告のうち、必ずしも、全ての測定結果の報告が必要というわけでもない。すなわち、無線ネットワーク側では、特定の状況下の測定結果の報告を必要としている場合も想定される。この場合、必要でない(必要性の低い)情報の測定の実行及び該測定結果の報告は、余り意味をなさない。
・セルの種類(ヘテロジニアス・ネットワーク(Heterogeneous Network:HetNet)におけるマクロセル/マイクロ/ピコかフェムトセル(オープン、クローズド、ハイブリッド)か、又は、
・隣接セルリストのセルか隣接セルリスト外のセルか、又はブラックリストのセルか)
等を用いるようにしてもよい。
ヘテロジニアスネットワーク(Heterogeneous Network:HetNet)における、無線端末による隣接セルの種類の識別例について説明する。
・PCI/PSCだけでなく、
・member CSGセルが存在するトラッキングエリアと同じか否か、
・サービングセルがmember CSGセルの周辺にあるセルか否か、
等その他の情報も必要となる。また、
無線端末(UE)が、どのCSGセルのmemberでもない場合、且つ、PCI/PSCでCSGセルか否かが判定できる場合、検出したPCI/PSCでCSGセル(この場合、non-member)であるか否かを判定する。
・帰属(サービング)セルのRSRQが予め定められた所定閾値より低く、
・さらに隣接セルの最大(あるいは上位N番目までの)RSRPが予め定められた所定閾値より低い場合に、
周辺に強い干渉となる、non-member CSGセルがあると判定する。なお、この方法では、該CSGセルの干渉(受信品質)を測定報告はしないが、代わりに“強い干渉となるCSGセルが存在する”ということを通知するようにしても良い。
11 測定指示取得部
12 測定実施部
13 測定結果報告部
20 基地局/基地局制御局
21 測定指示部
22 測定結果取得部
23 測定結果報告部
24 無線パラメータ設定変更部
30 OAM/SONサーバ
31 測定結果取得部
33 無線パラメータ設定指示部
Claims (24)
- 第1の無線局と、
前記第1の無線局と同種の第2の無線局及び/又は前記第1の無線局と異種の第3の無線局と、
前記第1の無線局に帰属する無線端末と、
前記第1乃至第3の無線局の少なくとも1つと設定情報を交換する運用管理サーバと、
を備え、
前記第1の無線局は、前記無線端末に対して1つ以上の前記第2又は前記第3の無線局からの下り信号の受信品質の測定を指示し、
前記無線端末は、前記指示に従い前記測定を行い、
前記第1の無線局及び前記運用管理サーバの少なくとも1つが、
前記無線端末による測定結果の報告を受け、前記報告から前記無線局の種類を識別して、前記第1乃至第3の無線局の少なくとも1つの無線局の無線ネットワーク設定の変更の要否の判断、及び、前記無線ネットワーク設定の変更の少なくとも1つを実行する手段を備えた、ことを特徴とする無線通信システム。 - 前記第1の無線局及び前記運用管理サーバの少なくとも1つによる前記無線ネットワーク設定の変更が、カバレッジ及びセル間干渉の少なくとも1つの最適化を目的とするものである、ことを特徴とする請求項1記載の無線通信システム。
- 前記第1の無線局及び前記運用管理サーバの少なくとも1つは、
前記第2の無線局からの干渉又は干渉信号の受信品質が予め定められた第1の所定レベル以下であり、且つ、
前記第3の無線局からの干渉又は干渉信号の受信品質が予め定められた第2の所定レベル以上である場合、
前記無線ネットワーク設定の変更を行わない、ことを特徴とする請求項1又は2記載の無線通信システム。 - 前記第1の無線局及び前記運用管理サーバの少なくとも1つは、
前記第2の無線局からの干渉又は干渉信号の受信品質が予め定められた第1の所定レベル以下であり、且つ、
前記第3の無線局からの干渉又は干渉信号の受信品質が予め定められた第2所定レベル以上である場合、
前記第1の無線局と前記第3の無線局との間のセル間干渉の最適化を、前記第1の無線局及び前記第2の無線局の少なくとも1つにおけるカバレッジの最適化よりも優先して実行する、ことを特徴とする請求項1又は2記載の無線通信システム。 - 前記第1の所定レベルと前記第2の所定レベルの間に所定のオフセット値を有する、ことを特徴とする請求項3又は4記載の無線通信システム。
- 前記第1の無線局及び前記運用管理サーバの少なくとも1つは、
前記第2の無線局からの干渉又は干渉信号の受信品質が予め定められた第3の所定レベル以上である報告が予め定められた第1の所定閾値未満であり、且つ、
前記第3の無線局からの干渉又は干渉信号の受信品質が予め定められた第4の所定レベル以上である報告が、予め定められた第2の所定閾値以上である場合、
前記無線ネットワーク設定の変更を行わない、ことを特徴とする請求項1又は2記載の無線通信システム。 - 前記第1の無線局及び前記運用管理サーバの少なくとも1つは、
前記第2の無線局からの干渉又は干渉信号の受信品質が予め定められた第3の所定レベル以上である報告が予め定められた第1の所定閾値未満であり、且つ、
前記第3の無線局からの干渉又は干渉信号の受信品質が予め定められた第4の所定レベル以上である報告が予め定められた第2の所定閾値以上である場合、
前記第1の無線局と前記第3の無線局との間のセル間干渉の最適化を、前記第1の無線局及び前記第2の無線局の少なくとも1つにおけるカバレッジの最適化よりも優先して実行する、ことを特徴とする請求項1又は2記載の無線通信システム。 - 前記第3の所定レベルと前記第4の所定レベルの間に所定のオフセット値を有する、ことを特徴とする請求項6又は7記載の無線通信システム。
- 前記第1、第2の無線局がマクロセルの基地局であり
前記第3の無線局がフェムトセルの基地局であり、
前記無線端末は、前記第1の無線局からの測定の指示を受け、帰属するマクロセルと隣接セルの下り信号の受信品質を測定し、測定結果を前記第1の無線局に報告し、
前記第1の無線局は、前記無線端末からの前記報告を前記運用管理サーバに送信し、
前記運用管理サーバでは、前記無線端末から前記第1の無線局を介して送信された測定報告の内容を測定の対象となった隣接セルの種類別に集計し、
隣接セルの受信品質が予め定められた所定値以上である報告が、予め定められた所定数以上である隣接セルがマクロセルの場合、
前記マクロセルの最適化が必要と判断し、
隣接セルの受信品質が前記所定値以上である報告が前記所定数以上の隣接セルがフェムトセルの場合、
前記フェムトセルの最適化が必要と判断し、
前記第1乃至第3の無線局のうち少なくとも1つの該等する無線局に対して、カバレッジ及びセル間干渉の少なくとも1つの最適化のために前記無線ネットワーク設定の調整を指示する、ことを特徴とする請求項2記載の無線通信システム。 - 前記第1、第2の無線局がマクロセルの基地局であり
前記第3の無線局がフェムトセルの基地局であり、
前記無線端末は、前記第1の無線局からの測定の指示を無線で受け、帰属するマクロセルと隣接セルの受信品質を測定し、測定結果を前記第1の無線局に報告し、
前記第1の無線局では、前記無線端末から前記第1の無線局を介して送信された測定報告の内容を測定の対象となった隣接セルの種類別に集計した上で前記運用管理サーバに報告し、
前記運用管理サーバでは、
隣接セルの受信品質が予め定められた所定値以上である報告が、予め定められた所定数以上の隣接セルがマクロセルの場合、
前記マクロセルの最適化が必要と判断し、
隣接セルの受信品質が前記所定値以上である報告が前記所定数以上の隣接セルがフェムトセルの場合、
前記フェムトセルの最適化が必要と判断し、
前記第1乃至第3の無線局のうち少なくとも1つの該等する無線局に対して、カバレッジ及びセル間干渉の少なくとも1つの最適化のために前記無線ネットワーク設定の調整を指示する、ことを特徴とする請求項2記載の無線通信システム。 - 前記第1の無線局及び前記運用管理サーバの少なくとも1つは、
隣接セルの受信品質が前記所定値以上である報告が前記所定数以上の前記隣接セルがマクロセルである場合には、
カバレッジ増減によるカバレッジ最適化を実行し、
フェムトセルである場合には、フェムトセルからの干渉回避を実行する、ことを特徴とする請求項6記載の無線通信システム。 - 前記第1、第2の無線局がマクロセルの基地局であり
前記第3の無線局がフェムトセルの基地局であり、
前記無線端末は、前記第1の無線局からの測定の指示を無線で受け、帰属するマクロセルと隣接セルの受信品質を測定し、測定結果を前記第1の無線局に報告し、
前記第1の無線局では、
前記無線端末から前記第1の無線局を介して送信された測定報告の内容を測定の対象となった隣接セルの種類別に集計し、前記第1の無線局で最適化が必要であると判断した場合、最適化を実行した上で前記運用管理サーバに報告し、
前記運用管理サーバでは、
隣接セルの受信品質が予め定められた所定値以上である報告が、予め定められた所定数以上の隣接セルがマクロセルの場合、
前記マクロセルの最適化が必要と判断して最適化を実行し、
隣接セルの受信品質が前記所定値以上である報告が前記所定数以上の隣接セルがフェムトセルの場合、
前記フェムトセルの最適化が必要と判断し、
対応する前記第2の無線局又は前記第3の無線局に対して最適化のために前記無線ネットワーク設定の調整を指示する、ことを特徴とする請求項1又は2記載の無線通信システム。 - 前記第1、第2の無線局がマクロセルの基地局であり
前記第3の無線局がフェムトセルの基地局であり、
前記第1の無線局のセルに隣接するフェムトセルの基地局からの下りリファレンス信号の受信品質(RSRP(Reference Signal Received Power)/RSRQ(Reference Signal Received Quality))が予め定められた所定値以上である報告件数が、予め定められた所定数以上あり、且つ、
前記第1の無線局のセルに隣接するマクロセルの基地局からの下りリファレンス信号の受信品質(RSRP/RSRQ)が予め定められた所定値以上である報告件数が、前記所定数未満である場合には、
マクロセル間のカバレッジ増減、干渉回避は行わず、
前記隣接マクロセルの基地局からの下りリファレンス信号の受信品質(RSRP/RSRQ)が予め定められた所定値以上である報告件数が予め定められた前記所定値以上の場合には、
マクロセルのカバレッジ増減、干渉回避の為の最適化を行う、ことを特徴とする請求項1又は2記載の無線通信システム。 - 前記無線端末は、アイドル状態で測定及び記録を行い、
アイドル状態で、カバレッジホールを検出したのち、前記第1の無線局と無線リンクを確立してアクティブ状態となり、前記第1の無線局に測定結果を報告する、ことを特徴とする請求項1又は2記載の無線通信システム。 - 前記第1、第2の無線局がマクロセルの基地局であり
前記第3の無線局がフェムトセルの基地局であり、
前記第1の無線局が、
フェムトセルの干渉が支配的である報告を予め定められた所定数以上受けていても、マクロセルのカバレッジ最適化の為の無線ネットワーク設定の変更は行なわず、
隣接マクロセルの干渉が支配的である報告を予め定められた所定数以上受けている場合には、
前記隣接マクロセルの基地局の無線ネットワーク設定を変更し、カバレッジ最適化を図る、ことを特徴とする請求項1又は2記載の無線通信システム。 - 第1の無線局から無線端末に対して、前記第1の無線局と同種の第2の無線局及び前記第1の無線局と異種の第3の無線局の少なくとも一方からなる1つ以上の無線局から受ける干渉の測定を指示し、
前記無線端末は前記指示に従い測定を行い、
前記第1の無線局及び運用管理サーバの少なくとも1つにより、
前記無線端末による測定結果の報告を受け、前記報告から前記無線局の種類を識別して、前記第1の無線局乃至第3の無線局の少なくとも1つの無線局の無線ネットワーク設定の変更の要否の判断、及び前記無線ネットワーク設定の変更の少なくとも1つを実行する、ことを特徴とする無線通信方法。 - 前記第1の無線局及び前記運用管理サーバの少なくとも1つによる無線ネットワーク設定の変更が、カバレッジ及びセル間干渉の少なくとも1つの最適化を目的とするものである、ことを特徴とする請求項16記載の無線通信方法。
- 前記第1の無線局及び前記運用管理サーバの少なくとも1つでは、
前記第2の無線局からの干渉又は干渉信号の受信品質が予め定められた第1の所定レベル以下であり、且つ、
前記第3の無線局からの干渉が又は干渉信号の受信品質予め定められた第2の所定レベル以上である場合、
前記無線ネットワーク設定の変更を行わないか、又は、
前記第1の無線局と前記第3の無線局との間のセル間干渉の最適化を、前記第1の無線局及び前記第2の無線局の少なくとも1つにおけるカバレッジの最適化よりも優先して実行する、ことを特徴とする請求項16又は17記載の無線通信方法。 - 前記運用管理サーバでは、前記無線端末から前記第1の無線局を介して送信された測定報告の内容を測定の対象となった隣接セルの種類別に集計し、
隣接セルの受信品質が予め定められた所定値以上である報告が、予め定められた所定数以上の隣接セルがマクロセルの場合、
前記マクロセルの最適化が必要と判断し、
隣接セルの受信品質が前記所定値以上である報告が前記所定数以上の隣接セルがフェムトセルの場合、
前記フェムトセルの最適化が必要と判断し、
前記第1乃至第3の無線局のうち少なくとも1つの該等する無線局に対して、カバレッジ及びセル間干渉の少なくとも1つの最適化ために前記無線ネットワーク設定の調整を指示する、ことを特徴とする請求項16又は17記載の無線通信方法。 - 無線端末と無線接続する無線局であって、
前記無線端末に対して、前記無線局と同種の第2の無線局及び前記無線局と異種の第3の無線局の少なくとも一方からなる1つ以上の無線局から受ける干渉の測定を指示し、
前記無線端末による測定結果の報告を受け、前記報告から前記無線局の種類を識別して、前記第1乃至第3の無線局の少なくとも1つの無線局の無線ネットワーク設定の変更の要否の判断、及び、前記無線ネットワーク設定の変更の少なくとも1つを実行する手段を備えた、ことを特徴とする無線局。 - 前記第2の無線局からの干渉又は干渉信号の受信品質が予め定められた第1の所定レベル以下であり、且つ、
前記第3の無線局からの干渉及び干渉信号の受信品質の少なくとも1つが予め定められた第2の所定レベル以上である場合、
前記無線ネットワーク設定の変更を行わないか、
前記第1の無線局と前記第3の無線局との間のセル間干渉の最適化を、前記第1の無線局及び前記第2の無線局の少なくとも1つにおけるカバレッジの最適化よりも優先して実行する、ことを特徴とする請求項20記載の無線局。 - 第1の無線局が、無線端末に対して、前記第1の無線局と同種の第2の無線局及び前記第1の無線局と異種の第3の無線局の少なくとも一方からなる1つ以上の無線局から受ける干渉の測定を指示し、
前記無線端末による測定結果の報告を前記第1の無線局を介して受け取り、前記報告から前記無線局の種類を識別して、前記第1乃至第3の無線局の少なくとも1つの無線局の無線ネットワーク設定の変更の要否の判断、及び、前記無線ネットワーク設定の変更の少なくとも1つを実行する手段を備えた、ことを特徴とする運用管理サーバ装置。 - 前記第2の無線局からの干渉又は干渉信号の受信品質が予め定められた第1の所定レベル以下であり、且つ、
前記第3の無線局からの干渉又は干渉信号の受信品質が予め定められた第2の所定レベル以上である場合、
前記運用管理サーバ装置は、
前記無線ネットワーク設定の変更を行わないか、
前記第1の無線局と前記第3の無線局との間のセル間干渉の最適化を、前記第1の無線局及び/又は前記第2の無線局におけるカバレッジの最適化よりも優先して実行する、ことを特徴とする請求項22記載の運用管理サーバ装置。 - 隣接セルの受信品質が予め定められた所定値以上である報告が、予め定められた所定数以上の隣接セルがマクロセルの場合、
前記マクロセルの最適化が必要と判断し、
隣接セルの受信品質が前記所定値以上である報告が前記所定数以上の隣接セルがフェムトセルを含む場合、
フェムトセルの最適化が必要と判断し、
前記第1乃至第3の無線局のうち少なくとも1つの該等する無線局に対して、カバレッジ及びセル間干渉の少なくとも1つの最適化のために前記無線ネットワーク設定の調整を指示する、請求項22記載の運用管理サーバ装置。
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CN103141128B (zh) | 2017-05-24 |
EP2624614A1 (en) | 2013-08-07 |
EP2624614B1 (en) | 2015-11-25 |
US9294950B2 (en) | 2016-03-22 |
EP2624614A4 (en) | 2014-03-12 |
US20130170362A1 (en) | 2013-07-04 |
CN103141128A (zh) | 2013-06-05 |
JPWO2012043307A1 (ja) | 2014-02-06 |
JP5862569B2 (ja) | 2016-02-16 |
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