WO2012093888A2 - Dispositif et procédé permettant de sélectionner une cellule dans un système de communication sans fil - Google Patents

Dispositif et procédé permettant de sélectionner une cellule dans un système de communication sans fil Download PDF

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Publication number
WO2012093888A2
WO2012093888A2 PCT/KR2012/000152 KR2012000152W WO2012093888A2 WO 2012093888 A2 WO2012093888 A2 WO 2012093888A2 KR 2012000152 W KR2012000152 W KR 2012000152W WO 2012093888 A2 WO2012093888 A2 WO 2012093888A2
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WIPO (PCT)
Prior art keywords
cell
terminal
cre bias
cre
bias
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PCT/KR2012/000152
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English (en)
Korean (ko)
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WO2012093888A3 (fr
Inventor
김시형
권기범
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주식회사 팬택
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Priority claimed from KR1020110080310A external-priority patent/KR20120080514A/ko
Application filed by 주식회사 팬택 filed Critical 주식회사 팬택
Publication of WO2012093888A2 publication Critical patent/WO2012093888A2/fr
Publication of WO2012093888A3 publication Critical patent/WO2012093888A3/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/04—Reselecting a cell layer in multi-layered cells
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/24—Reselection being triggered by specific parameters
    • H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
    • H04W36/302—Reselection being triggered by specific parameters by measured or perceived connection quality data due to low signal strength
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/24—Reselection being triggered by specific parameters
    • H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
    • H04W36/305—Handover due to radio link failure
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/02—Access restriction performed under specific conditions

Definitions

  • the present invention relates to wireless communication, and more particularly, to an apparatus and method for cell selection in a wireless communication system.
  • Wireless communication systems are widely deployed to provide various kinds of communication services such as voice and data.
  • a wireless communication system is a multiple access system that can support communication with multiple users by sharing available system resources (bandwidth, transmission power, etc.).
  • multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and single carrier frequency (SC-FDMA). division multiple access) system.
  • CDMA code division multiple access
  • FDMA frequency division multiple access
  • TDMA time division multiple access
  • OFDMA orthogonal frequency division multiple access
  • SC-FDMA single carrier frequency division multiple access
  • a heterogeneous network environment in which various cells coexist in a short distance is being considered.
  • a micro cell having relatively low power transmission power such as a pico cell and a femto cell
  • the cell can be classified into an open access (OA) cell that can be serviced at any time if necessary without a separate access restriction, and a closed subscriber group (CSG) cell that allows access only to specific users.
  • OA open access
  • CSG closed subscriber group
  • cell selection is a technique for the UE to select a specific cell to receive the service.
  • the cell selection may include initial cell selection for selecting a cell to be initially connected after the terminal is powered on, and cell reselection for selecting a cell again while the terminal stays in the cell.
  • cell selection includes initial cell selection and cell reselection.
  • the terminal searches for a radio channel for cell selection. When the UE finds a suitable cell that satisfies the cell selection criteria, the UE selects the corresponding cell.
  • the terminal having a high data traffic may select the pico cell.
  • the quality of service may be deteriorated. Therefore, a load balancing technique for properly distributing terminals between the pico cell and the macro cell is needed.
  • a cell selection method considering heterogeneous networks requires a method for satisfying load balancing without changing actual transmission power.
  • offset values are used without actually controlling the transmission power to balance the load, a method of compensating for performance degradation caused by intercell interference power in an extended cell region is urgently needed.
  • the present invention provides an apparatus and method for performing cell selection between a macro cell and a micro cell in a wireless communication system.
  • the present invention provides an apparatus and method for performing handover between a macro cell and a micro cell in a wireless communication system.
  • the present invention provides an apparatus and method for pre-detecting a closed user group (CSG) cell between a macro cell and a micro cell in a wireless communication system.
  • CSG closed user group
  • the present invention provides an apparatus and method for adjusting cell coverage in a wireless communication system.
  • the present invention provides an apparatus and method capable of effectively adjusting the load between cells in a wireless communication system.
  • the present invention provides an apparatus and method for preventing a terminal from detecting a CSG cell in advance and falling into a radio link failure state in a wireless communication system.
  • a method in which a terminal performs detection / cell selection / handover of a CSG cell in advance may include receiving a first cell range expansion (CRE) bias through a first message; Receiving a second CRE bias with a modified 1 CRE bias via a second message and performing cell selection / handover based on the second CRE bias, wherein the first and second CRE bias are micro ( Macro) is an offset added to the signal strength of the cell, and the sum of the signal strength of the second CRE bias and the micro (macro) cell is greater than the signal strength of the macro (micro) cell and is allowed to the micro (macro) cell (allowed-UE ), The micro (macro) cell is selected / handed over.
  • CRE cell range expansion
  • the micro cell when the sum of the CRE bias of the second micro cell and the signal strength of the micro cell is greater than the signal strength of the macro cell for a predetermined time, the micro cell may be selected by the terminal.
  • the first and second messages may be cell specific messages of the serving / neighbor cell, or may be terminal specific messages of the serving cell, and the first message is a cell specific message of the serving / neighbor cell and the second message. May be a terminal specific message of the serving cell.
  • a method for adjusting cell coverage by a base station in a wireless communication system includes receiving a measurement result or terminal capability from at least one terminal or network in a cell, based on the measurement result Determining whether to adjust the coverage; correcting the CRE bias when the coverage of the cell is determined; and transmitting the modified CRE bias to the at least one terminal.
  • a cell selection and handover method of a terminal in a wireless communication system includes the steps of: determining, by the terminal, whether the cell is a CSG cell to which the terminal cannot access; transmitting a CRE bias to the terminal; Receiving a measurement result reflecting the CRE bias from the terminal; And if it is determined that the measurement restriction is necessary based on the measurement result, transmitting a measurement limit setting command to the terminal.
  • the at least one terminal performs cell selection / handover based on the modified CRE bias, wherein the modified CRE bias is an offset added to the signal strength of the micro cell, and the modified CRE bias and the signal strength of the micro cell are adjusted. If the sum is greater than the signal strength of the macro cell, the micro cell may be selected / handed over.
  • the modified CRE bias may be transmitted through a cell specific message or may be transmitted through a terminal specific message.
  • the CSG bias value of the CSG cell is given to an unauthorized terminal, thereby preventing the UE from entering the CSG cell and detecting the CSG cell in advance before falling into the RLF due to severe interference from the CSG base station. It may be.
  • load balancing between cells in a wireless communication system can be made more efficient, and cell coverage can be effectively adjusted.
  • the terminal can guarantee a higher quality of service (QoS), and in particular, the terminal that is not allowed to the closed subscriber group (CSG) cell detects the CSG cell in advance and falls into a radio link failure (RLF). It has the advantage of being preventable.
  • QoS quality of service
  • CSG closed subscriber group
  • RLF radio link failure
  • FIG. 1 is a diagram schematically illustrating the concept of a network consisting of a macro cell, a femto cell and a pico cell.
  • FIG 2 illustrates cell selection or handover according to an embodiment of the present invention.
  • FIG 3 illustrates cell selection or handover according to an embodiment of the present invention.
  • FIG 4 illustrates cell selection or handover according to an embodiment of the present invention.
  • FIG 5 illustrates cell selection or handover according to an embodiment of the present invention.
  • FIG 6 illustrates cell selection or handover according to an embodiment of the present invention.
  • FIG. 7 is a flowchart illustrating a general handover process.
  • FIG. 8 is a flowchart illustrating a handover process according to an embodiment of the present invention.
  • FIG 9 illustrates an example in which a CRE bias is not applied based on a terminal category according to an embodiment of the present invention.
  • FIG. 10 illustrates an example of applying a CRE bias based on a terminal category according to an embodiment of the present invention.
  • FIG. 11 is a flowchart illustrating an operation of a terminal in an RRC connected state for performing handover according to the present invention.
  • FIG. 12 is a flowchart illustrating a process of reselecting a cell using a cell selection offset according to the present invention.
  • FIG. 13 illustrates another example of a cell reselection process using a cell selection offset according to the present invention.
  • FIG. 14 is a flowchart illustrating the operation of a base station according to an embodiment of the present invention.
  • FIG. 15 is a flowchart schematically illustrating an embodiment in which a CSG cell is present in a system to which the present invention is applied.
  • FIG. 16 is a diagram schematically illustrating an embodiment in which a CSG cell is present in a system to which the present invention is applied.
  • 17 is a block diagram of a transmission and reception apparatus according to an embodiment of the present invention.
  • the wireless communication system will be described as an example, and in particular, a next generation wireless communication system supporting a plurality of CCs will be described as an example.
  • one embodiment of the present specification provides asynchronous wireless communication that evolves to Long Term Evolution (LTE) and LTE-advanced (LTE-A) through GSM, WCDMA, and HSPA, and synchronous evolution to CDMA, CDMA-2000, and UMB. It can be applied to a wireless communication system.
  • LTE Long Term Evolution
  • LTE-A LTE-advanced
  • a wireless communication system includes a user equipment (UE) and a base station (evolved Node-B, eNB), and the terminal may be fixed or mobile, and may have a mobile station (MS) and a mobile terminal (MT). It may be called other terms such as a user terminal (UT), a subscriber station (SS), a wireless device, a personal digital assistant, a wireless modem, a handheld device, and the like. It may also be called a terminal, a user and a user device.
  • a base station generally refers to a fixed station for communicating with a terminal, and may be referred to by other terms such as a base transceiver system (BTS) and an access point.
  • the eNB may provide services for one or more cells. Meanwhile, a cell may be classified into a macro cell or a micro cell based on coverage (or maximum transmission power). Macro cells have wider coverage or greater transmit power than micro cells.
  • the micro cell may be referred to in other terms, such as a pico cell, a femto cell.
  • a heterogeneous network may be configured as a network in which a micro cell exists within the coverage of a macro cell.
  • micro cells such as pico cells and femto cells is not particularly limited, but in general, pico cells are communication shadow areas that are not covered by macro cells alone, or areas where data service demands are high, so-called hot zones. It can be used to.
  • pico cells are communication shadow areas that are not covered by macro cells alone, or areas where data service demands are high, so-called hot zones. It can be used to.
  • femto cells may be generally used in indoor offices or homes.
  • FIG. 1 is a diagram schematically illustrating a concept of a heterogeneous network including a macro cell, a femto cell, and a pico cell.
  • FIG. 1 illustrates a heterogeneous network composed of a macro cell, a femto cell, and a pico cell for convenience of description, the heterogeneous network may include a relay or another type of cell.
  • a macro cell 10, a femto cell 20, and a pico cell 30 are operated together in a heterogeneous network.
  • the macro cell 10, femto cell 20, and pico cell 30 each have their own cell coverages 10, 20, 30.
  • a femto cell is a low power wireless access point, which is a small base station for mobile communication used indoors such as a home or an office.
  • a femto cell can access a mobile communication core network using DSL or cable broadband in a home or office.
  • Cells may be classified into open access (OA) cells and closed subscriber group (CSG) cells according to user accessibility.
  • the CSG cell basically aims to provide specialized services only to members belonging to the CSG.
  • the micro cell may be an OA cell or a CSG cell.
  • the terminal may be defined and used as a pico-cell user equipment (PUE) and a macro-cell user equipment (MUE).
  • PUE is a terminal that uses a micro cell such as a pico cell as a serving cell.
  • PUE the terminal including the micro cell as the serving cell.
  • the MUE is a terminal having a macro cell as a serving cell.
  • the state of the UE is divided into an RRC connected state and an RRC idle state according to whether the RRC is connected to the radio resource control (RRC).
  • RRC radio resource control
  • the UE operates as follows. At this time, one or several of the following operations may be performed simultaneously or sequentially. In each state, you can do the following, but that doesn't mean that they happen sequentially:
  • the terminal is configured with UE-specific Discontinuous Reception (DRX) by non-access stratum (NAS).
  • DRX is a function of controlling the terminal to stop the reception operation and sleep (sleep) in order to reduce the power consumption of the terminal.
  • a cell selection and cell reselection process may be performed to find a suitable cell as a serving cell to a corresponding UE among neighbor cells.
  • the cell reselection process refers to a process for moving to the best cell in the state of cell selection.
  • the terminal monitors system information (SI) transmitted from a serving cell.
  • SI system information
  • the serving cell refers to a cell that has completed camp-on.
  • the camp-on refers to a state in which the terminal completes a cell selection or reselection process and monitors system information and paging information.
  • the terminal monitors a paging channel.
  • the terminal operates as follows. At this time, one or several of the following operations may be performed simultaneously or sequentially. In each state, you can do the following, but that doesn't mean that they happen sequentially:
  • the terminal may transmit / receive unicast data.
  • the terminal may configure and operate a terminal specific DRX defined by a media access control (MAC) layer of the base station.
  • MAC media access control
  • the terminal monitors the paging channel, SIB1 (System Information Block Type 1), system information, control channel, and the like. At this time, the monitor is progressed at a different period from the RRC idle state (generally shorter than the cycle of the RRC idle state).
  • the base station may transmit information constituting the operation of the terminal so that the terminal can obtain the channel information, the terminal transmits the channel quality information (CQI), measurement information and the like to the base station according to the configured information You can report.
  • CQI channel quality information
  • the base station may handover the terminal to the neighbor cell.
  • the cell to be handed over may be another base station of the same frequency band (hereinafter, an intra-frequency base station), the same base station of another frequency band or another base station (hereinafter, an inter-frequency base station). Or an inter-RAT (inter-RAT (Radio Access Technologies)) base station using another radio transmission scheme.
  • CRE Cell range expansion
  • load balancing may be performed when traffic loads of several cells are unevenly distributed. For example, when over-traffic occurs in a cell, a user may be sent from the cell where the over-traffic occurs to another cell through a handover or a cell reselection method.
  • CRE bias refers to an offset added to the signal strength of a cell to apply CRE.
  • Smc the signal strength of the micro cell
  • Smm the signal strength of the macro cell
  • Sb the CRE bias
  • Sb1 refers to the first CRE bias
  • Sb2 refers to the second CRE bias
  • Sb3 refers to the third CRE bias.
  • the MUE may perform handover to the micro cell.
  • Sb the higher the probability that the MUE is handed over to the micro cell, and serves to increase the coverage of the micro cell.
  • a variable used in the handover process may be used.
  • Variables used in the handover process include Ocn and Ocs.
  • Ocn is a cell specific offset value added to the measured value of the adjacent cell
  • Ocs is a cell specific offset value added to the measured value of the serving cell.
  • Default values of the Ocn and the Ocs may be set to 0, and the Ocn and the Ocs are transmitted through an RRC message.
  • the value of the Ocn and Ocs when the value of the Ocn and Ocs has the same value for a plurality of terminals, it may be transmitted through a cell specific message, when the different Ocn and Ocs is set for each terminal, the value of the Ocn and Ocs May be transmitted through a terminal specific message.
  • the UE specific message is a message transmitted to a specific UE in a cell, and includes an RRC message and a MAC message, and the messages are transmitted through a physical downlink shared channel (PDSCH) or a physical downlink control channel (PDCCH). Can be sent through.
  • PDSCH physical downlink shared channel
  • PDCCH physical downlink control channel
  • the cell specific message may include an RRC message including system information transmitted to all UEs in the cell, and the RRC message may be transmitted through a PDSCH or through a broadcasting channel (PBCH).
  • RRC message including system information transmitted to all UEs in the cell
  • PBCH broadcasting channel
  • the signal strength is an index indicating power / quality of a corresponding cell, and parameters such as CQI (Channel Quality Indicator), RSRP (Reference Signal Received Power) and / or RSRQ (Reference Signal Received Quality) may be used.
  • CQI Channel Quality Indicator
  • RSRP Reference Signal Received Power
  • RSRQ Reference Signal Received Quality
  • the RSRP refers to a linear average of power of resource elements (REs) carrying a cell-specific reference signal (CRS) in a measurement frequency band.
  • RSRQ may be expressed as N * RSRP / (E-UTRA carrier RSSI), where N denotes the number of RBs in the Evolved Universal Terrestrial Radio Access (E-UTRA) carrier RSSI measurement band, and the E-UTRA carrier RSSI (Received) Signal Strength Indicator) refers to a linear average value of a signal received in an entire OFDM symbol including RS of antenna port 0 at a measurement frequency.
  • the RSSI is a value that includes both interference and thermal noise of adjacent channels.
  • FIG 2 illustrates cell selection or handover according to an embodiment of the present invention.
  • the PUE 300 is in the first coverage 210 of the micro cell 200 and uses the micro cell 200 as a serving cell. Assume that the CRE bias at this time is Sb1. That is, the first coverage 210 of the micro cell 200 is set to Sb1.
  • the micro cell 200 adjusts the CRE bias Sb1 to inform the PUE 300 of the CRE bias Sb2 having a smaller value than before.
  • the adjusted CRE bias Sb2 may inform the PUE 300 by the micro cell 200 through a terminal specific message.
  • the second coverage 220 of the adjusted micro cell 200 is smaller than the first coverage 210 in the determination for cell selection or handover.
  • the PUE 300 may select the macro cell 100 or perform a handover to the macro cell 100.
  • FIG 3 illustrates cell selection or handover according to an embodiment of the present invention.
  • the adjusted CRE bias Sb2 informs the PUE 300 through the cell specific message by the micro cell 200. All terminals in the micro cell 200 may receive the adjusted CRE bias Sb2.
  • the PUE 300 may select the macro cell 100 or perform a handover to the macro cell 100.
  • FIG 4 illustrates cell selection or handover according to an embodiment of the present invention.
  • the MUE 300 is within the coverage of the macro cell 100 and uses the macro cell 100 as a serving cell.
  • CRE bias be Sb1.
  • the macro cell 100 adjusts the CRE bias Sb1 to inform the MUE 300 of the CRE bias Sb3 having a larger value than before.
  • the adjusted CRE bias Sb3 may inform the MUE 300 through the UE-specific message by the macro cell 100.
  • the second coverage 260 of the adjusted micro cell 200 is larger than the first coverage 250 in the determination for cell selection or handover.
  • the MUE 300 may perform handover or cell selection to the micro cell 200.
  • FIG 5 illustrates cell selection or handover according to an embodiment of the present invention.
  • the adjusted CRE bias Sb3 (CRE bias with a larger value than before) is transmitted through a cell specific message of the micro cell 200, and the MUE 300 listens to the adjusted CRE bias Sb3 ( listen).
  • the second coverage 260 of the adjusted micro cell 200 becomes larger than the first coverage 250 in the determination for cell selection or handover.
  • the MUE 300 may perform cell selection or handover to the micro cell 200.
  • the coverage boundary of the cell may be in various forms such as an actual circle or an ellipse.
  • cell coverage may be applied in various forms.
  • the MUE 310 belongs to the coverage of the macro cell in the determination of cell reselection even if it is separated by the same distance from the base station of the micro cell
  • the MUE 300 may belong to the coverage of the micro cell. That is, it is conceivable to induce cell reselection or handover by adjusting the CRE bias only for the MUE 300.
  • the adjusted CRE bias Sb3 that is, the CRE bias Sb3 having a larger value than before, is transmitted to the MUE 300 through a terminal specific message of the macro cell 100.
  • the adjusted second coverage 260 of the micro cell 200 becomes larger than the first coverage 250.
  • the MUE 300 may perform cell selection or handover to the micro cell 200.
  • the micro cell becomes a hot spot zone.
  • the hot spot area refers to a cell with a relatively high load. If the value of the CRE bias is fixed, a situation in which the micro cell cannot cover all the terminals may occur when the load of the micro cell is increased. On the contrary, consider the case where the number of terminals in the micro cell is small and the number of terminals in the macro cell is relatively large. If the bias value is fixed, it is difficult to balance the load because it is difficult to handover the terminal to the micro cell.
  • a unique CRE bias can be designated for each UE. Even in a terminal located at the same location, link reliability (e.g., an error rate) varies depending on the capability of the terminal, so that a CRE bias can be specified for each terminal to provide an appropriate service to each terminal. have. The coverage of the micro cell may vary for each terminal.
  • FIG. 7 is a flowchart illustrating a general handover process.
  • the source base station prepares for handover with the target base station (S720).
  • the source base station notifies the terminal of the RRC connection reconfiguration (S730), it performs a random access procedure (S740).
  • the UE informs the target base station of the RRC connection reconfiguration complete (S750).
  • a cell selection or handover method for balancing a load using a CRE bias will be described by dividing a case where the UE is in an RRC connected state and a case where the UE is in an RRC idle state.
  • the UE may be a MUE or a PUE.
  • the base station means a macro base station
  • the base station means a pico base station (or femto base station).
  • a UE in an RRC connection state reports a measurement result to a base station (S810).
  • the measurement result may be a measurement result of reporting a measurement result measured periodically, or may be an event-triggering measurement result measured when an event occurs.
  • Table 1 shows an example of an event that the terminal reports to the base station.
  • Table 1 event Report purpose A1 The signal strength of the serving cell is greater than the threshold A2 The signal strength of the serving cell is less than the threshold A3 The signal strength of the neighboring cell is offset by more than the serving cell plus the additional margin A4 NAVER cell has signal strength above threshold A5 The signal strength of the serving cell is less than the first threshold and the signal strength of the neighbor cell is greater than the second threshold.
  • B1 Signal strength of inter RAT neighbor cell is higher than threshold B2
  • the signal strength of the serving cell is less than the first threshold, and the signal strength of the inter RAT navigator cell is greater than the second threshold.
  • the terminal reports the events of A1 to B2 to the base station according to each purpose.
  • the occurrence report of the event and the measurement result measured at this time may be the selection criteria of the handover.
  • the base station requests a change of the CRE bias from the mobility management entity (MME) based on the measurement result or the performance of the terminal (S820).
  • MME mobility management entity
  • the base station may change the CRE bias value based on the measurement result.
  • the MME informs the base station of the changed CRE bias in response to the request (S830). If the MME can command the change of the CRE bias value without the request of the base station, the base station may change the CRE bias value based on the CRE bias transmitted by the MME. In this case, step S810 or S820 may be omitted.
  • MMEs managing cells affected by the changed CRE bias when MMEs managing cells affected by the changed CRE bias are different, information exchange between MMEs (loading of cells managed by MMEs, base station configuration information (paging configuration), and the number of antennas of a base station) , Frequency band to be used) and the like can be used to change the CRE bias value.
  • MME1 MME managing the macro base station
  • MME2 the MME managing the pico base station is called. Let's call it MME2. If the pico base station requests the MME2 to change the CRE bias, the MME2 may exchange this information with the MME1 and then inform each base station of the changed CRE bias.
  • the information transmitted to the base station by the MME may be an RFSP index (RAT / Frequency Selection Priority Index) determined by the MME based on an operator's policy and context information of the terminal.
  • the RFSP index is terminal specific and is a value received by the MME from a home subscriber server (HSS).
  • HSS home subscriber server
  • the base station can change the CRE bias without the response of the MME based on the measurement result or the performance of the terminal measured in step S810.
  • steps S820 and S830 may be omitted.
  • the base station itself may determine the load balance to change the CRE bias value.
  • steps S810, S820, and S830 may be omitted.
  • Step S840 determines whether it is necessary to balance the load based on information (eg, over-traffic or the like) for the neighbor cell, and changes the CRE bias value (S840).
  • Step S840 does not change the CRE bias value when it is desired to change the CRE bias value for reasons other than load balancing or when it is not necessary to balance the load. That is, step S840 is optionally performed.
  • the base station transmits a CRE bias to the terminal (S850).
  • the modified CRE bias is transmitted through steps S810 to S840. If the CRE bias is not changed as all or part of steps S810 to S840 are omitted, the CRE bias is transmitted without changing the CRE bias.
  • the CRE bias may be transmitted through a cell specific message or a terminal specific message.
  • the CRE bias may be transmitted through a broadcast channel or a common channel, or may be transmitted through a dedicated channel.
  • the terminal performs a handover process based on the received CRE bias (S860).
  • the handover process is performed by applying the received CRE bias to the measurement result.
  • the handover process may proceed simultaneously with the UE receiving the CRE bias from the base station in step S850.
  • steps S810 to S860 described in FIG. 8 may also be applied to an example in which the UE hands over from a serving cell to a target cell.
  • the terminal reports the measurement result to the serving cell.
  • the measurement result may be a measurement result measured periodically or an event-triggered measurement result measured when an event occurs.
  • the serving cell requests the target cell to change the CRE bias based on the measurement result or the performance of the UE.
  • the serving cell may change the CRE bias value based on the measurement result.
  • the target cell informs the serving cell of the changed CRE bias in response to the request. If the target cell can instruct the change of the CRE bias value without the request of the serving cell, the serving cell can change the CRE bias value based on the CRE bias transmitted to the target cell. On the other hand, the serving cell can change the CRE bias based on the measurement result or the performance of the UE measured without the response of the target cell. Alternatively, the serving cell may determine the load balance by itself and change the CRE bias value.
  • the serving cell determines whether the load needs to be balanced based on information on the neighbor cell (for example, whether over traffic or the like), and changes the CRE bias value. If you want to change the CRE bias value for reasons other than load balancing, or if you do not need to balance the load, do not change the CRE bias value.
  • the serving cell transmits a CRE bias to the terminal. If the CRE bias is changed in the previous procedure, the changed CRE bias is transmitted. If the CRE bias is not changed, the CRE bias is transmitted without changing the CRE bias.
  • the CRE bias may be transmitted through a cell specific message or a terminal specific message.
  • the CRE bias may be transmitted over a broadcast channel or a shared channel, or may be transmitted over a dedicated channel.
  • the terminal performs handover based on the received CRE bias. Handover is performed by applying the received CRE bias to the measurement result. Handover may proceed simultaneously with the UE receiving the CRE bias from the serving cell.
  • the CRE bias may be transmitted through a cell specific message or may be transmitted through a terminal specific message. That is, CRE bias can be applied cell-specifically, but UE-specific can also be applied. For example, cell selection or handover may be performed by applying a CRE bias based on a terminal category.
  • the category of the terminal may be a category for distinguishing whether the terminal is a high-end terminal or a low-end terminal, and other types of categories may be possible.
  • FIG 9 illustrates an example in which a CRE bias is not applied based on a terminal category.
  • the CRE bias based on the category of the UE in order to balance the load effectively while maintaining the system throughput through the CRE bias. You can apply the value.
  • FIG. 10 illustrates an example in which a CRE bias is applied based on a terminal category according to the present invention.
  • a terminal-specific CRE bias value is applied.
  • the CRE bias is applied to include the high-end terminal and not the low-end terminal based on the category of the terminal.
  • the area of the pico cell is extended to the range including the high-end terminal.
  • the low-end terminal is not included. Therefore, the number of UEs included in the region 930 of the extended pico cell is smaller than when the cell-specific CRE bias value is applied.
  • it is more selective and effective to load balance while maintaining the gain (eg system gain) that can be gained by using CRE.
  • FIG. 11 is a flowchart illustrating an operation of a terminal in an RRC connected state in performing a handover according to the present invention.
  • the terminal receives a CRE bias (S1110).
  • the measurement result is reported to the base station based on the received CRE bias value (S1120).
  • the measurement result may include at least one of RSRP, RSRQ, CQI, and an event.
  • the terminal reports the event A3 to the base station.
  • the base station proceeds to handover according to the present invention from the serving cell to the neighbor cell (S1130). For example, the handover described with reference to FIGS. 8 to 10 may be performed.
  • the cell selection criteria are as follows.
  • S rxlev is a cell selection reception (RX) level value and a unit is decibel (dB).
  • S qual is a cell selection quality value and the unit is decibels.
  • Q rxlevmeas is the measured cell RX level value and Q qualmeas is the measured cell quality value.
  • Q rxlevmin is the minimum value of the required RX level in the cell, and the unit is dBm. dBm is the actual power (milliwatt) converted to dB (decibels).
  • Q qualmin is the minimum of the required quality level in the cell and is in dB.
  • Q rxlevminoffset is an offset value used to determine the S rxlev value, and periodically searches for the original land network (PLNM) when camping on another site (VLMN). By performing a search, the offset value is given to the user's network so that the user's network can be accessed.
  • Q qualminoffset is also an offset value used to determine S qual for the same purpose.
  • P compensation is the larger value of PEMAX-P powerClass and 0
  • PEMAX is the maximum value of the uplink Transmission (TX) power level used by the terminal allowed by the upper layer
  • P PowerClass is the terminal The maximum value of the RF (Radio Frequency) output power of a terminal according to a power class.
  • the cell reselection criteria are as follows.
  • Q meas is the RSRP measurement value (quantity) to be used in the cell reselection
  • Qoffset is intra- If a case that the frequency cell reselection, Qoffset s, n is present, and Qoffset s, n value, and if not 0 to be.
  • the Qoffset value refers to an offset value additionally applied to the RSRP measurement value of the neighbor cell in the cell reselection process.
  • Qoffset s, n is an offset between the serving cell and the neighbor cell.
  • the Qoffset s, n value may have a value of ⁇ 24 dB to 24 dB and may be set in units of 2 dB.
  • Q offsetfrequency can be used when inter-frequency cell reselection (because one base station operates differently for each frequency, there is a concept of handover and reselection).
  • Offset which is a variable used to give priority to each frequency in the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) of LTE. For example, this offset can be used to balance the load to prevent the user from being concentrated in the preferred frequency band. Therefore, the higher the R value including both the R value, that is, R s and R n values, the terminal preferentially selects the corresponding cell when the cell is reselected.
  • RSRQ considered in the present invention is as follows.
  • the RSRQ may be expressed as N * RSRP / (E-UTRA carrier RSSI), where N is an Evolved Universal Terrestrial Radio Access (E-UTRA) carrier RSSI measurement block in all RBs in a frequency band ) Means the number. In general, it may be the downlink frequency bandwidth of one cell.
  • E-UTRA Evolved Universal Terrestrial Radio Access
  • the E-UTRA carrier RSSI Received Signal Strength Indicator
  • the RSSI is a linear average of signals received on all OFDM symbols with respect to OFDM symbols including RS among the signals transmitted through antenna port 0 at the RSSI measurement frequency. It means the value.
  • the RSSI is a value that includes both interference and thermal noise of adjacent channels. If the UE receives an indication of the subframe for the RSRQ measurement from a higher layer (for example, when the UE receives information for distinguishing between the RSRQ measurable subframe and the RSRQ non-measurable subframe), the UE at the RSSI measurement All OFDM symbols of the indicated subframe are measured, not just the OFDM symbols including the RS.
  • the measured RSRQ value may be applied to the RRC idle mode and the RRC connected mode, and may also be applied to the same frequency band and different frequency band as the current serving cell for each mode.
  • the RSRQ value is measured at an antenna connector of the UE.
  • the terminal in the macro cell or pico cell is determined from an upper layer. It is assumed that the subframe for the RSRQ measurement is received, and the idle mode UE starts measuring the RSSI in all OFDM symbols of the subframe in which the RSRQ measurement is indicated during the RSRQ measurement. If the UE does not have information for distinguishing between the RSRQ measurable subframe and the RSRQ non-measurable subframe from the eNB, the UE determines that RSRQ measurement has been indicated for all subframes.
  • the terminal may activate a Time Divisino Multiplexing (TDM) enhanced Inter Cell Interference Coordination (eICIC) mode.
  • TDM Time Divisino Multiplexing
  • eICIC enhanced Inter Cell Interference Coordination
  • an RRM measurement cycle that can be configured in the terminal may be changed. The measurement period is set in subframe units.
  • the FDD is changed to a cycle other than a multiple of 40 ms
  • the TDD is changed to a cycle that is not a multiple of 20 ms and 70 ms and 50 ms.
  • the predetermined specific value may be set to a fixed value, and may be set to one of 5 dB or 10 dB or 15 dB or 20 dB.
  • the threshold transmitted through the broadcasting channel may be transmitted through SIB4 and may be configured as shown in Table 2 below.
  • a terminal configured to set a macro cell or a pico cell as a serving cell may operate as follows. First, the terminal checks the information of the broadcasting channel received from the serving cell. It is checked whether there is a Qoffset s, n value for a neighbor cell among the information transmitted through the broadcasting channel. If the value does not exist, the value of Qoffset s, n neighbor cells is set to zero. If at least one piece of information on a neighbor cell whose absolute value of Qoffset s, n for a particular neighbor cell is greater than or equal to a threshold value is identified, the UE regards the subframe for measuring the RSRQ from an upper layer and receives the RSRQ in the idle mode. In the measurement, an operation of measuring RSSI in all OFDM symbols of a subframe indicated by RSRQ measurement is started.
  • the UE when the UE which sets the macro cell or the pico cell or the cell corresponding thereto as the serving cell confirms that the CSG cell such as the femto cell exists in the neighbor cell, the UE performs subframes for the RSRQ measurement from an upper layer. It is assumed that the indication is received, and when the RSRQ measurement is performed in the idle mode, the operation of measuring the RSSI in all OFDM symbols of the indicated subframe RSRQ measurement is started. If the UE does not have information for distinguishing between the RSRQ measurable subframe and the RSRQ non-measurable subframe from the eNB, the UE determines that RSRQ measurement has been indicated for all subframes.
  • the terminal may activate the TDM eICIC mode for the idle mode.
  • an RRM measurement cycle that can be configured in the terminal may be changed. The measurement period is set in subframe units.
  • the FDD is changed to a cycle other than a multiple of 40 ms
  • the TDD is changed to a cycle that is not a multiple of 20 ms and 70 ms and 50 ms.
  • the idle mode terminal may check a range of physical cell ID (PCI) values of CSG cells among information currently provided through a broadcasting channel in a camp-on cell, that is, a serving cell.
  • PCI physical cell ID
  • the csg-PhysCellIdRange field may not always be present when the cell transmitting the broadcasting channel is not a CSG cell. For example, if a CSG cell does not exist in a corresponding range within the cell and around the cell, the field may not exist. However, in the case of CSG, the csg-PhysCellIdRange field should always be included in the broadcasting channel.
  • the PhysCellIdRange field defining the range value of PCI may be defined as follows.
  • PhysCellIdRange SEQUENCE ⁇ start PhysCellId, range ENUMERATED ⁇ n4, n8, n12, n16, n24, n32, n48, n64, n84, n96, n128, n168, n252, n504, spare2, spare1 ⁇ OPTIONAL-Need OP ⁇
  • the meaning of a field value such as n4 indicates the number of consecutive PCI range values from the start value. For example, if the starting PCI value is 52 and the range value is n8, the PCI values that CSG cells may have are 52, 53,... , 59.
  • the idle mode terminal measures RSRP of neighbor cells. At this time, in order to distinguish each adjacent cell, PCI information included in a synchronization channel is checked and RSRP is measured using the checked PCI information. At this time, it is checked whether the checked PCI information exists within a range of PCI values of CSG cells through the broadcasted information. If the PCI value is determined to be a PCI value that is determined to be a CSG cell, the idle mode UE considers that the subframe for the RSRQ measurement is received from a higher layer, and the RSRQ measurement is indicated when the RSRQ measurement is instructed in the idle mode. The operation of measuring RSSI in all OFDM symbols starts.
  • the present invention intends to use the offset (Qoffsets, n) value as a CRE bias value.
  • the CRE bias may be transmitted through system information.
  • a variable for giving the CRE bias value to the UE for cell selection may additionally be included in the cell selection criteria. This variable may be transmitted through system information (for example, System Information Block 4 (SIB4)).
  • SIB4 System Information Block 4
  • a variable added to give a CRE bias value may be referred to as a cell selection offset (Offset_Cell_selection). That is, the variable called cell selection offset is an offset value used for the UE in the RRC idle state to apply the CRE bias.
  • the cell selection offset may be defined as an offset value added to the Q rxlevmeas or Q qualmeas value described in Equation 1 above.
  • the cell selection offset may have two values.
  • the CRE bias value for the low-end terminal and the CRE bias value for the high-end terminal may be included and transmitted based on the category of the terminal.
  • the terminal receiving the cell selection offset may select an offset value corresponding to its category and apply the CRE bias value to select the cell.
  • the base station may change the CRE bias value of the terminal based on the RFSP index received from the MME.
  • the RFSP index is UE-specific and is a value received by the MME from the HSS.
  • the UE may perform cell reselection based on this value.
  • FIG. 12 is a flowchart illustrating a process of reselecting a cell using a cell selection offset according to the present invention.
  • the UE may be a MUE or a PUE.
  • FIG. 12 is an embodiment when the UE is a MUE.
  • the UE may perform cell reselection from a macro base station to a pico base station.
  • SIB4 and SIB5 (System Information Block 5) of the system information can be received while the terminal is camped on, and includes information on neighbor cells.
  • SIB4 includes information of an intra-frequency neighbor cell
  • SIB5 includes information of an inter-frequency neighbor cell.
  • the cell selection offset may be transmitted through system information such as SIB4 or SIB5.
  • the Qoffset value described in Equation 2 may be used as a cell selection offset for applying a CRE bias value.
  • Qoffest refers to an offset value additionally applied to RSRP measurement values of neighbor cells in a cell reselection process.
  • the terminal UE camps on the macro base station (S1210).
  • the camp-on terminal receives system information from the camp-on one serving cell (here, the macro cell) (S1220).
  • the camp-on state is a cell selection state, and the selected cell becomes a serving cell.
  • the terminal receives system information such as SIB4 or SIB5 from the serving cell.
  • the base station (here, the macro base station) of the serving cell transmits a cell selection offset value through system information.
  • the UE measures and compares the signal strengths of the serving cell and the neighbor cell by applying the cell selection offset value received through the system information (S1230).
  • the cell is reselected based on the measurement result (S1240). For example, when the signal strength of a micro cell such as a pico cell is expressed as Smc, the signal intensity of a macro cell as Smm, and the cell selection offset is Qoffset, when "Smc + Qoffset> Smm" is maintained for a predetermined time, the macro cell
  • the MUE that has been camped on may perform cell reselection with a micro cell such as a pico cell. As a result of comparing the measured values of the neighbor cell and the serving cell is different due to the received cell selection offset value, the cell reselection process may be performed when the most suitable cell becomes the neighbor cell.
  • the terminal is a PUE
  • the PUE is an embodiment for cell reselection from the macro base station to the pico base station.
  • the terminal PUE camps on a pico cell (S1310).
  • the camp-on terminal receives system information from the camp-on one serving cell (here, the pico cell) (S1320).
  • the base station of the serving cell transmits a cell selection offset value through system information.
  • the terminal measures and compares the signal strengths of the serving cell and the neighbor cell by applying the cell selection offset value received through the system information (S1330).
  • the cell reselection process is performed based on the measurement result.
  • the signal strength of a micro cell such as a pico cell
  • the macro cell signal strength is Smm
  • the cell selection offset value is Qoffset
  • the PUE camping on the same micro cell as the cell may perform cell reselection to the macro cell.
  • the cell reselection process may be performed when the most suitable cell becomes the neighbor cell.
  • FIG. 14 is a flowchart illustrating the operation of a base station according to an embodiment of the present invention.
  • the base station receives information of the terminal and the network, such as measurement results and terminal performance from the terminal and the network (S1410). In consideration of the load balance and / or the measurement result and / or the terminal performance of the terminal, the base station determines whether to modify the CRE bias value of the terminal (S1420).
  • the CRE bias value is set to cell-specific or zero by default.
  • the base station may determine to modify the CRE bias value when the number of terminals in the cell increases. Or, if the channel state of the terminal worsens, the base station may determine to modify the CRE bias value. Alternatively, the correction of the CRE bias value may be determined according to the terminal performance.
  • the terminal performance may be, for example, a terminal category configured based on a transmit / receive capacity for the uplink / downlink of the terminal (for example, a memory size in the terminal), or a frequency supported by the corresponding terminal. It can be a band.
  • the supportable frequency band may be set based on the sizes of uplink and downlink frequency bands within a single serving cell, or when a plurality of serving cells are configured, based on the number and combination of serving cells configurable by the corresponding UE. Can be set.
  • the serving cell combination includes configurability for continuous serving cells and continuity for discontinuous serving cells.
  • the serving cell may consist of only a downlink component carrier or may include both a downlink component carrier and an uplink component carrier.
  • the terminal performance may be the maximum number of antenna ports that the terminal can support.
  • the number of antenna ports is defined by dividing downlink and uplink and may be configured independently.
  • the terminal performance may be defined as a combination of a frequency band that the terminal can support and the maximum number of antenna ports that can be supported.
  • the frequency band that the terminal can support is 20 MHz per serving cell
  • the maximum number of serving cells that can be supported is three
  • the maximum number of antenna ports is eight for downlink and four for uplink.
  • the combination of the possible frequency band and the maximum number of antenna ports that can be supported can be shown in Table 5.
  • the base station corrects the CRE bias (S1430). For example, if the CRE bias value is set differently based on the terminal category, the terminal whose terminal category is higher than or equal to a certain level (high-end, 'high-end') and lower (low-end, 'low-end') Other CRE bias values can be set for the UE.
  • the terminal category is composed of eight as shown in Table 6, when the terminal is defined as the performance between the terminal category step 4 to step 8, it is divided into high-end base station to the terminal for the high-end If the CRE bias value is set, and the UE is less than the UE category 4 step, it is divided into low-ends and the base station sets a CRE bias value for the low-end to the UE.
  • Table 6 UE Category Max. Data rate (DL / UL) (Mbps) DL UL Max. num. of DL-SCH TB bits per TTI Max. num. of DL-SCH per TB per TTI Total num. of soft channel bits Max. num. of spatial layers Max. num of UL-SCH TB bits per TTI Max.
  • the base station transmits the modified CRE bias to the terminal (S1440).
  • the modified CRE bias may be transmitted through a cell specific message or a terminal specific message.
  • the base station may adjust the CRE bias for the UE of the user so that the UE may respond to interference from the CSG cell in advance. .
  • the serving cell checks whether the serving cell is a CSG cell which is a neighbor cell of the (not allowed) (S1510).
  • the UE checks the PCI of the CSG cell and checks the CSG ID on its white list to inform the serving cell of whether the UE is allowed in the CSG cell or not.
  • the white list is a set of cells that the terminal can enter, which is received from a higher layer.
  • the serving cell transmits the CRE bias considering the CSG cell to the terminal (S1520).
  • the serving cell transmits a CRE bias only to a terminal that is not allowed to access the CSG cell, thereby preventing the terminal receiving the CRE bias from receiving more interference from the CSG cell.
  • the prevention is the introduction of eICIC technology, which deliberately feels that an unauthorized user is subjected to interference from the CSG cell before being severely interrupted by the CSG cell, thereby allowing the serving cell to measure eICIC technology early.
  • the measurement of the serving cell may be applied only to the ABS (Almost Blank Subframe) of the CSG cell.
  • ABS is used to protect a resource that is interfered with by an aggressive cell.
  • the ABS reduces or does not transmit power such as control information, data information, and signaling (signals transmitted for channel measurement and synchronization) transmitted through the subframe.
  • control information data information
  • signaling signals transmitted for channel measurement and synchronization
  • an ABS may use a multimedia broadcast single frequency network (MBSFN) subframe.
  • MMSFN multimedia broadcast single frequency network
  • the serving cell may transmit a CRE bias only to a terminal that is not allowed to access the CSG cell.
  • the CRE bias is a value greater than zero.
  • the serving cell may transmit different CRE biases to the UE that is allowed to access the CSG cell and the UE that is not allowed to access the CSG cell.
  • the base station can apply the measurement limitation to the terminal early, thereby preventing unnecessary handover requests, RLF generation, and the like.
  • the serving cell may determine whether the corresponding terminal is a terminal that can access the CSG cell in various ways.
  • the CRE bias may be transmitted through a terminal specific message.
  • the CRE bias can be transmitted through a broadcast channel or a common channel.
  • the CRE bias may be sent over a dedicated channel.
  • the CRE bias may be a variable used in the existing measurement process. This variable may be a cell specific message or a terminal specific message.
  • the UE may perform measurement (hereinafter, referred to as 'measurement') related to channel state or communication quality and report this to the serving cell (S1530). At this time, the terminal reports the measured value reflecting the CRE bias to the serving cell.
  • 'measurement' measurement related to channel state or communication quality
  • the serving cell receiving the measured value reflecting the CRE bias may transmit a command for setting a limit to the measurement performed by the UE in advance before the UE is greatly influenced by the interference from the CSG cell (S1540).
  • the serving cell determines that the measurement value needs to be limited by determining the measurement value with the CRE bias reflected. Restrictions necessary for the measurement of the terminal can be added. For example, the serving cell may limit the measurement to the UE to perform measurement on a subframe in which interference is low among the downlink subframe patterns used by the CSG cell.
  • the serving cell may misrecognize a channel state or a communication state. Therefore, when the UE enters the CSG cell and already receives a large amount of interference from the CSG cell, in case of limiting the measurement or taking necessary measures, the UE may be in a RLF (Radio Link Failure) state due to interference from the CSG cell. have. Therefore, the serving cell may allow the UE to set measurement limits in consideration of interference from neighboring CSG cells before the UE is affected by the interference.
  • RLF Radio Link Failure
  • the UE may perform the measurement based on the restricted content and report it to the serving cell (S1550).
  • the limitation of the measurement is that the measurement is performed on a subframe that can receive less interference from the CSG cell as described above, and thus, the measurement results on the subframe that is severely interfered with the CSG cell, thereby falling into an unnecessary RLF state. The phenomenon can be prevented. Therefore, the serving cell may perform appropriate inter-cell interference coordination so that the UE can avoid the interference of the CSG cell.
  • the CRE bias is transmitted to the terminal and the measurement result reflecting the measurement result is confirmed, and then the measurement limit setting command is transmitted to the terminal.
  • the CRE bias and the measurement limit setting command are transmitted together to the terminal. Can be. For example, if an Ocn variable value for an unacceptable cell is received above 0, the terminal may start measurement restriction.
  • the UE may perform the measurement in which the measurement limit is reflected without performing an unnecessary operation (no longer) such as requesting a handover to the corresponding CSG cell.
  • FIG. 16 is a diagram schematically illustrating an embodiment in which a CSG cell is present in a system to which the present invention is applied. 16, the embodiment described with reference to FIG. 15 may be specifically confirmed.
  • UE 1 (UE 1; 1640) and UE 2 (UE 2; 1650) are terminals having a macro cell 1610 as a serving cell.
  • the terminal 1 1640 is a terminal that is not allowed to access
  • the terminal 2 1650 is a terminal that is allowed to access. Accordingly, in case of entering the CSG cell, UE 2 1650 does not need to take additional action by handing over to the CSG cell, but UE 1 1640 cannot handover to the CSG cell and is affected by interference by the CSG cell.
  • the macro cell base station 1610 confirms that the terminal 1 1640 is adjacent to the CSG cell, and transmits a CRE bias to the terminal 1 1640, before the terminal 1 1640 enters the CSG cell and the RLF is removed
  • the necessary measures can be performed in advance.
  • the area of the CSG cell is the terminal 2 1650 that does not receive the CRE bias. It can be seen that can be determined differently. Accordingly, the UE 1640 may perform necessary measures such as setting a measurement limit in advance before entering the original CSG cell area.
  • 17 is a block diagram illustrating a wireless communication system in which an embodiment of the present invention is implemented.
  • the base station 50 includes a processor 51, a memory 52, and an RF unit 53.
  • the RF unit 53 is connected to the processor 51 and transmits and / or receives a radio signal.
  • the RF unit 53 may receive a measurement result report from the terminal, receive information related to an adjacent cell, for example, whether or not it can access a CSG cell, and transmit a CRE bias and a measurement limit command to the terminal. have.
  • the RF unit 53 may transmit and receive necessary information between other cells.
  • the base station may transmit and receive a CRE bias change request and a CRE bias change response between adjacent cells through the RF unit 53.
  • the memory 52 is connected to the processor 51 and stores various information for driving the processor 51.
  • the memory 52 may include information about a measurement report transmitted by a terminal, information about a CRE bias transmitted to a terminal, information about a CSE bias transmitted and received between neighboring cells, and / or a relationship between a terminal and a neighboring cell, such as
  • the terminal may store information on whether the terminal is a member of a specific CSG cell.
  • the processor 51 may be connected to the memory 52 and the RF unit 53 to control them.
  • the processor 51 may determine the CRE bias based on the measurement report received from the terminal, and may perform a procedure regarding a CRE change among other cells in this regard. Meanwhile, the processor 51 may determine whether the cell adjacent to the terminal is a CSG cell, the terminal is a member of the corresponding CSG cell, and determine a CRE bias to be transmitted to the terminal. It may be determined whether to make a setting and delivered to the terminal.
  • the terminal 60 includes a processor 61, a memory 62, and an RF unit 63.
  • the RF unit 63 is connected to the processor 61 and transmits and / or receives a radio signal.
  • the RF unit 63 may transmit a measurement result or information about a neighboring cell, such as whether the neighboring cell is a CSG cell or can be connected to the corresponding CSG cell, to the base station, and information on the CRE bias and / or measurement limitation from the base station.
  • a setup command can be received.
  • the memory 62 is connected to the processor 61 and stores various information for driving the processor 61.
  • the memory 62 may store information on the CRE bias received from the base station, and may store the information about the CRE bias when the base station transmits a measurement limit setting command.
  • the processor 61 is connected to the RF unit 63 and the memory 62 to control them. Processor 61 performs the measurements to report to the base station. In this case, the processor 61 may perform the measurement by reflecting the CRE bias received from the base station, and may perform the measurement by reflecting the measurement limit received from the base station. In addition, the processor 61 may transmit information about an adjacent cell to the base station through the RF unit 63. For example, if it is confirmed that the neighboring cell is a CSG cell to which it cannot connect, the processor 61 may transmit information related thereto to the base station.
  • the processor may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, and / or data processing devices.
  • the memory may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium and / or other storage device.
  • the RF unit may include a baseband circuit for processing a radio signal.
  • the above-described technique may be implemented as a module (process, function, etc.) for performing the above-described function.
  • the module may be stored in memory and executed by a processor.
  • the memory may be internal or external to the processor and may be coupled to the processor by various well known means.

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Abstract

La présente invention concerne un dispositif et un procédé permettant de sélectionner une cellule dans un système de communication sans fil. L'invention permet à un terminal de recevoir une première polarisation d'expansion portée de cellule (CRE) par le biais d'un premier message et de recevoir une seconde polarisation CRE, dans lequel la première polarisation CRE est modifiée, par le biais d'un second message, de sorte qu'une cellule soit sélectionnée sur la base de ladite seconde polarisation CRE. Dans ce cas, lesdites première et seconde polarisations CRE sont des décalages qui sont ajoutés à l'intensité de signal d'une micro-cellule, et ainsi, ledit terminal sélectionne la macro-cellule si une somme de la seconde polarisation CRE et de l'intensité de signal de la macro-cellule est supérieure à l'intensité de signal d'une macro-cellule. Puisque la présente invention fournit différentes valeurs de polarisation CRE à un utilisateur non autorisé pour une cellule CSG et à un utilisateur autorisé associé, l'utilisateur non autorisé pour la cellule CSG peut confirmer la cellule CSG à l'avance, empêchant ainsi une défaillance de liaison radio (RLF).
PCT/KR2012/000152 2011-01-07 2012-01-06 Dispositif et procédé permettant de sélectionner une cellule dans un système de communication sans fil WO2012093888A2 (fr)

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KR20110012569 2011-02-11
KR20110029113 2011-03-30
KR10-2011-0029113 2011-03-30
KR1020110080310A KR20120080514A (ko) 2011-01-07 2011-08-11 무선 통신 시스템에서 셀 선택하는 장치 및 방법
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CN103648129A (zh) * 2013-12-04 2014-03-19 上海交通大学无锡研究院 一种基于负载均衡和QoS的异构网络切换方法
CN103813385A (zh) * 2012-11-13 2014-05-21 中国移动通信集团河南有限公司 一种小区业务资源的分配方法和设备
WO2014165807A1 (fr) * 2013-04-05 2014-10-09 Kyocera Corporation Gestion dynamique de transition de zone de couverture radio avec transfert intercellulaire coordonné
RU2606398C1 (ru) * 2012-11-13 2017-01-10 Телефонактиеболагет Л М Эрикссон (Пабл) Способ и устройство запуска особого режима работы для терминалов, работающих на увеличенной большой дальности
CN106471837A (zh) * 2014-07-02 2017-03-01 三星电子株式会社 用于无线通信系统中的小区间负载均衡的方法和装置
WO2018160009A1 (fr) * 2017-02-28 2018-09-07 삼성전자 주식회사 Procédé et appareil de transfert intercellulaire dans un système de communication sans fil prenant en charge une fonction eicic
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US10097990B2 (en) 2012-11-13 2018-10-09 Telefonaktiebolaget L M Ericsson (Publ) Method and apparatus for triggering of specific operation mode for terminals operating in extended long range
US10631253B2 (en) 2012-11-13 2020-04-21 Telefonaktiebolaget L M Ericsson (Publ) Method for modifying parameter values for long range extension and corresponding node
US10136369B2 (en) 2013-03-29 2018-11-20 Alcatel Lucent Method, apparatus, and system for biasing adjustment of cell range expansion
US9801109B2 (en) 2013-04-05 2017-10-24 Kyocera Corporation Dynamic radio coverage area transition management with coordinated handover
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US11463363B2 (en) 2014-07-02 2022-10-04 Samsung Electronics Co., Ltd. Method and apparatus for inter-cell load balance in wireless communication system
CN106471837A (zh) * 2014-07-02 2017-03-01 三星电子株式会社 用于无线通信系统中的小区间负载均衡的方法和装置
US10123356B2 (en) 2015-04-27 2018-11-06 Telefonaktiebolaget Lm Ericsson (Publ) Robust selection of PRACH repetition level for MTC enhanced coverage
US11337083B2 (en) 2015-12-11 2022-05-17 Telefonaktiebolaget Lm Ericsson (Publ) Radio network node and a wireless device, and methods therein
WO2018160009A1 (fr) * 2017-02-28 2018-09-07 삼성전자 주식회사 Procédé et appareil de transfert intercellulaire dans un système de communication sans fil prenant en charge une fonction eicic
US11259226B2 (en) 2017-02-28 2022-02-22 Samsung Electronics Co., Ltd. Handover method and apparatus in wireless communication system supporting eICIC function

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