WO2014168452A1 - Procédé de changement de cellule dans un système de communications sans fil en réseau hétérogène et appareil associé - Google Patents

Procédé de changement de cellule dans un système de communications sans fil en réseau hétérogène et appareil associé Download PDF

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Publication number
WO2014168452A1
WO2014168452A1 PCT/KR2014/003155 KR2014003155W WO2014168452A1 WO 2014168452 A1 WO2014168452 A1 WO 2014168452A1 KR 2014003155 W KR2014003155 W KR 2014003155W WO 2014168452 A1 WO2014168452 A1 WO 2014168452A1
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Prior art keywords
small cell
cell
terminal
mac
base station
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PCT/KR2014/003155
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English (en)
Korean (ko)
Inventor
허강석
정명철
권기범
안재현
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Pantech Co Ltd
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Pantech Co Ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/16—Performing reselection for specific purposes
    • H04W36/18—Performing reselection for specific purposes for allowing seamless reselection, e.g. soft reselection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0055—Transmission or use of information for re-establishing the radio link
    • H04W36/0058—Transmission of hand-off measurement information, e.g. measurement reports
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0055—Transmission or use of information for re-establishing the radio link
    • H04W36/0069—Transmission or use of information for re-establishing the radio link in case of dual connectivity, e.g. decoupled uplink/downlink
    • 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
    • H04W36/14—Reselecting a network or an air interface
    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W80/00—Wireless network protocols or protocol adaptations to wireless operation
    • H04W80/02—Data link layer protocols

Definitions

  • the present invention relates to wireless communication, and more particularly, to a device and a method for changing a cell to an area of another small cell terminal.
  • HetNet heterogeneous network
  • a macro cell In a heterogeneous network environment, a macro cell is a large coverage cell, and a small cell such as a femto cell and a pico cell is a small coverage cell. Coverage overlap occurs between multiple macro cells and small cells in a heterogeneous network environment.
  • a terminal connected to a network may communicate with any cell according to a channel environment or a mobile state, and may perform cell change.
  • handover may be performed to solve a problem of call disconnection that occurs when moving to an adjacent cell.
  • the terminal may perform wireless communication through any one of base stations constituting at least one serving cell.
  • a terminal that is connected to one base station constituting a macro cell is serviced by the other base station without a handover procedure even when the signal quality of the other base station constituting the small cell is excellent and the radio resource utilization is low. Is not provided. Therefore, there is a need for a technique for distributing an excessive load or a load requiring a specific QoS to a small cell without a handover procedure in a heterogeneous network environment and efficiently transmitting data.
  • the terminal may receive a service through a different frequency band from the small base station including the small cell and the macro base station including the macro cell. This is also called a dual connection of the terminal.
  • the purpose of dual connectivity is to improve performance using small cells.
  • the terminal may simultaneously receive services from two base stations, thereby increasing the capacity of the terminal using the small cell.
  • the macro base station having the terminal context manages the terminal, but the small base station that includes only a part or no part of the terminal context does not.
  • QoS for macro base stations e.g., VoIP
  • QoS for small base stations requiring transmission / reception to which data can be allocated.
  • the MAC / PHY must be secured through the interface between the macro base station and the small base station. In this case, the delay of the interface (eg, non-ideal backhaul) Due to this, the cell change may not be performed at an appropriate time.
  • An object of the present invention is to provide a method and apparatus for changing a cell when a terminal changes a small cell area.
  • Another technical problem of the present invention is to prevent frequent handover of the terminal and to provide data without interruption.
  • Another technical problem of the present invention is to continuously receive a service through a cell change when a dual-connected terminal moves to another small cell area.
  • a method of changing a cell of a terminal moving from a first small cell region overlapped with a macro cell to a second small cell region may include information related to the strength of a radio signal measured by the terminal.
  • Reporting to the first base station for the macro cell receiving a structure change message from the first base station instructing to selectively re-configure the data radio bearer (DRB) of the second small cell
  • DRB data radio bearer
  • PDCP Packet Data Convergence Protocol
  • RLC Radio Link Control
  • the terminal for changing the cell is a measurement unit for measuring the strength of the radio signal
  • DRB data radio bearer
  • PDCP Packet Data Convergence
  • a method of changing a cell of a terminal moving from a first small cell region overlapped with a macro cell by a base station to a second small cell region by a base station may be used.
  • Receiving the MAC and PHY layer related information from the second small cell receiving information related to the strength of the radio signal measured by the terminal from the terminal, based on the information related to the strength of the measured radio signal
  • DRB data radio bearer
  • a base station for changing a cell of a terminal moving from a first small cell region overlapped with a macro cell to a second small cell region may include a MAC and a MAC of the second small cell.
  • a receiver which receives PHY layer related information from the second small cell and receives information related to the strength of the radio signal measured by the terminal from the terminal, based on the information related to the strength of the measured radio signal A structure for instructing to selectively re-establishment the data radio bearer (DRB) of the second small cell based on a control unit for determining to use the two small cells instead of the small cell and the MAC and PHY layer related information.
  • DRB data radio bearer
  • continuous service is possible without loss of user data in a situation where dual connectivity between a macro cell and a small cell and a terminal is configured in a network.
  • the macro cell when a cell change is performed between small cells overlapped with a macro cell, the macro cell may secure MAC / PHY information of the target small cell in advance.
  • the terminal may quickly perform the cell change when it is determined that the cell change is necessary.
  • FIG. 1 shows a wireless communication system to which the present invention is applied.
  • FIG. 2 is a block diagram illustrating a radio protocol structure for a user plane.
  • FIG. 3 is a block diagram illustrating a radio protocol architecture for a control plane.
  • FIG. 4 shows a structure of a bearer service in a wireless communication system to which the present invention is applied.
  • FIG. 5 is a diagram schematically illustrating a concept of a heterogeneous network including a macro base station, a femto base station, and a pico base station according to the present invention.
  • FIG. 6 is a diagram illustrating a scenario to which the present invention is applied.
  • FIG. 8 is a flowchart illustrating an example of a method of changing a DRB between small cells while maintaining a DRB with a macro cell according to the present invention.
  • FIG. 9 is a flowchart illustrating an example of an operation of a terminal for changing a DRB between small cells according to the present invention.
  • FIG. 10 is a flowchart illustrating an example of an operation of a base station for changing a DRB between small cells while maintaining a DRB with a macro cell according to the present invention.
  • FIG. 11 is a block diagram illustrating an example of an apparatus for changing a DRB between small cells according to the present invention.
  • FIG. 1 shows a wireless communication system to which the present invention is applied.
  • the wireless communication system 10 is widely deployed to provide various communication services such as voice and packet data.
  • the wireless communication system 10 includes at least one base station 11 (evolved NodeB, eNB).
  • Each base station 11 provides a communication service for specific cells 15a, 15b, and 15c.
  • the cell can in turn be divided into a number of regions (called sectors).
  • the UE 12 may be fixed or mobile, and may include a mobile station (MS), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, and a PDA. (personal digital assistant), wireless modem (wireless modem), a handheld device (handheld device) may be called other terms.
  • the base station 11 may be called by other terms such as a base station (BS), a base transceiver system (BTS), an access point, an femto base station, a home node B, a relay, and the like.
  • the cell should be interpreted in a comprehensive sense of a part of the area covered by the base station 11 and encompasses various coverage areas such as megacells, macrocells, small cells, microcells, picocells, and femtocells.
  • the base station 11 may provide at least one cell to the terminal.
  • the cell may mean a geographic area where the base station 11 provides a communication service or may mean a specific frequency band.
  • the cell may mean a downlink frequency resource and an uplink frequency resource. Alternatively, the cell may mean a combination of a downlink frequency resource and an optional uplink frequency resource.
  • Downlink means communication from the base station 11 to the terminal 12
  • uplink means communication from the terminal 12 to the base station (11).
  • the transmitter may be part of the base station 11 and the receiver may be part of the terminal 12.
  • the transmitter may be part of the terminal 12 and the receiver may be part of the base station 11.
  • Wireless communication systems include Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier-FDMA (SC-FDMA), and OFDM-FDMA
  • CDMA Code Division Multiple Access
  • TDMA Time Division Multiple Access
  • FDMA Frequency Division Multiple Access
  • OFDMA Orthogonal Frequency Division Multiple Access
  • SC-FDMA Single Carrier-FDMA
  • OFDM-FDMA OFDM-FDMA
  • Various multiple access schemes such as OFDM, TDMA, and OFDM-CDMA may be used.
  • the uplink transmission and the downlink transmission may use a time division duplex (TDD) scheme that is transmitted using different times, or may use a frequency division duplex (FDD) scheme that is transmitted using different frequencies.
  • TDD time division duplex
  • FDD frequency division duplex
  • the physical downlink control channel informs the terminal of resource allocation of a paging channel (PCH) and downlink shared channel (DL-SCH) and hybrid automatic repeat request (HARQ) information related to the DL-SCH.
  • the PDCCH may carry an uplink grant informing the UE of resource allocation of uplink transmission.
  • the DL-SCH is mapped to a physical downlink shared channel (PDSCH).
  • the physical control format indicator channel (PCFICH) informs the UE of the number of OFDM symbols used for PDCCHs and is transmitted every subframe.
  • PHICH Physical Hybrid ARQ Indicator Channel
  • PUCCH Physical uplink control channel
  • PUSCH Physical uplink shared channel
  • PRACH physical random access channel
  • FIG. 2 is a block diagram illustrating a radio protocol architecture for a user plane.
  • the 3 is a block diagram illustrating a radio protocol structure for a control plane.
  • the user plane is a protocol stack for user data transmission
  • the control plane is a protocol stack for control signal transmission.
  • a physical layer (PHY) layer provides an information transfer service to a higher layer using a physical channel.
  • the physical layer is connected to the upper layer Medium Access Control (MAC) layer through a transport channel.
  • MAC Medium Access Control
  • Transport channels are classified according to how and with what characteristics data is transmitted over the air interface. Data moves between the physical layers, that is, between the physical layers of the transmitter and the receiver.
  • the physical channel may be modulated by an orthogonal frequency division multiplexing (OFDM) scheme and utilizes time and frequency as radio resources.
  • OFDM orthogonal frequency division multiplexing
  • the physical downlink control channel informs the terminal of resource allocation of a paging channel (PCH) and downlink shared channel (DL-SCH) and hybrid automatic repeat request (HARQ) information related to the DL-SCH.
  • the PDCCH may carry an uplink scheduling grant informing the UE of resource allocation of uplink transmission.
  • the physical control format indicator channel (PCFICH) informs the UE of the number of OFDM symbols used for PDCCHs and is transmitted every subframe.
  • PHICH physical Hybrid ARQ Indicator Channel
  • PHICH physical Hybrid ARQ Indicator Channel
  • Physical uplink control channel (PUCCH) carries uplink control information such as HARQ ACK / NAK, scheduling request, and CQI for downlink transmission.
  • Physical uplink shared channel carries an uplink shared channel (UL-SCH).
  • the functions of the MAC layer include mapping between logical channels and transport channels and multiplexing / demultiplexing into transport blocks provided as physical channels on transport channels of MAC service data units (SDUs) belonging to the logical channels.
  • the MAC layer provides a service to a Radio Link Control (RLC) layer through a logical channel.
  • RLC Radio Link Control
  • the logical channel may be divided into a control channel for transmitting control region information and a traffic channel for delivering user region information.
  • RLC layer Functions of the RLC layer include concatenation, segmentation, and reassembly of RLC SDUs.
  • the RLC layer In order to guarantee the various quality of service (QoS) required by the radio bearer (RB), the RLC layer has a transparent mode (TM), an unacknowledged mode (UM), and an acknowledged mode (Acknowledged Mode). Three modes of operation (AM).
  • AM RLC provides error correction through an automatic repeat request (ARQ).
  • PDCP Packet Data Convergence Protocol
  • Functions of the Packet Data Convergence Protocol (PDCP) layer in the user plane include delivery of user data, header compression, and ciphering.
  • the functionality of the Packet Data Convergence Protocol (PDCP) layer in the user plane includes the transfer of control plane data and encryption / integrity protection.
  • the RRC layer is responsible for the control of logical channels, transport channels, and physical channels in connection with configuration, re-configuration, and release of RBs.
  • RB means a logical path provided by the first layer (PHY layer) and the second layer (MAC layer, RLC layer, PDCP layer) for data transmission between the terminal and the network.
  • the configuration of the RB means a process of defining characteristics of a radio protocol layer and a channel to provide a specific service, and setting each specific parameter and operation method.
  • the RB may be further classified into a signaling RB (SRB) and a data RB (DRB).
  • SRB is used as a path for transmitting RRC and NAS messages in the control plane
  • DRB is used as a path for transmitting user data in the user plane.
  • the non-access stratum (NAS) layer located above the RRC layer performs functions such as session management and mobility management.
  • the UE If there is an RRC connection between the RRC layer of the UE and the RRC layer of the E-UTRAN, the UE is in an RRC connected state, otherwise it is in an RRC idle state. do.
  • the downlink transmission channel for transmitting data from the network to the UE includes a BCH (Broadcast Channel) for transmitting system information and a downlink shared channel (SCH) for transmitting user traffic or control messages.
  • Traffic or control messages of a downlink multicast or broadcast service may be transmitted through a downlink SCH or may be transmitted through a separate downlink multicast channel (MCH).
  • the uplink transport channel for transmitting data from the terminal to the network includes a random access channel (RACH) for transmitting an initial control message and an uplink shared channel (SCH) for transmitting user traffic or control messages.
  • RACH random access channel
  • SCH uplink shared channel
  • BCCH broadcast control channel
  • PCCH paging control channel
  • CCCH common control channel
  • MCCH multicast control channel
  • MTCH multicast traffic
  • the physical channel is composed of several symbols in the time domain and several sub-carriers in the frequency domain.
  • One sub-frame consists of a plurality of OFDM symbols in the time domain.
  • One subframe consists of a plurality of resource blocks, and one resource block consists of a plurality of symbols and a plurality of subcarriers.
  • each subframe may use specific subcarriers of specific symbols (eg, the first symbol) of the corresponding subframe for the physical downlink control channel (PDCCH).
  • the transmission time interval (TTI) which is a unit time for transmitting data, is 1 ms corresponding to one subframe.
  • a terminal In order for a terminal to transmit user data (eg, an IP packet) to an external internet network or to receive user data from an external internet network, the terminal exists between mobile communication network entities existing between the terminal and the external internet network. Resources must be allocated to different paths. Thus, a path in which resources are allocated between mobile communication network entities and data transmission and reception is possible is called a bearer.
  • a bearer a path in which resources are allocated between mobile communication network entities and data transmission and reception is possible.
  • FIG. 4 shows a structure of a bearer service in a wireless communication system to which the present invention is applied.
  • the end-to-end service refers to a service that requires a path between the terminal and the P-GW (EPS Bearer) and a P-GW and an external bearer for the Internet network and data service.
  • the external path is a bearer between the P-GW and the Internet network.
  • the terminal In order for the terminal to transmit data to the external internet network, the terminal first transmits data to the base station eNB through the RB on the radio. The base station then transmits data to the S-GW through the S1 bearer. S-GW transmits data to P-GW through S5 / S8 bearer, and finally through external bearer to destinations in P-GW and external internet network.
  • the data can be delivered to the terminal through each bearer in the reverse direction as described above.
  • each bearer is defined for each interface to ensure independence between the interfaces.
  • the bearer at each interface will be described in more detail as follows.
  • the bearers provided by the wireless communication system are collectively called an Evolved Packet System (EPS) bearer.
  • An EPS bearer is a delivery path established between a UE and a P-GW for transmitting IP traffic with a specific QoS.
  • the P-GW may receive IP flows from the Internet or send IP flows to the Internet.
  • Each EPS bearer is set with QoS decision parameters that indicate the nature of the delivery path.
  • One or more EPS bearers may be configured per UE, and one EPS bearer uniquely represents a concatenation of one E-RAB and one S5 / S8 bearer.
  • the S5 / S8 bearer is a bearer of the S5 / S8 interface. Both S5 and S8 are bearers present at the interface between the S-GW and the P-GW.
  • the S5 interface exists when the S-GW and the P-GW belong to the same operator, and the S8 interface belongs to the provider (Visited PLMN) roamed by the S-GW, and the P-GW has subscribed to the original service (Home). PLMN).
  • the E-RAB uniquely represents the concatenated value of the S1 bearer and the corresponding RB.
  • E-RAB When there is one E-RAB, one-to-one mapping is established between the E-RAB and one EPS bearer. That is, one EPS bearer corresponds to one RB, S1 bearer, and S5 / S8 bearer, respectively.
  • the S1 bearer is a bearer at the interface between the base station and the S-GW.
  • RB means two types of data RB (Data Radio Bearer (DRB)) and signaling RB (Signaling Radio Bearer (SRB)).
  • DRB Data Radio Bearer
  • SRB Signaling Radio Bearer
  • the expression RB without distinction refers to data RB provided in the Uu interface to support a service of a user. to be. Therefore, an RB expressed without distinction is distinguished from a signaling radio bearer (SRB).
  • the RB is a path through which data of the user plane is transmitted
  • the SRB is a path through which data of the control plane, such as the RRC layer and NAS control messages, are delivered.
  • One-to-one mapping is established between RB, E-RAB and EPS bearer.
  • EPS bearer types include a default bearer and a dedicated bearer.
  • an IP address is assigned and a default EPS bearer is created while creating a PDN connection. That is, a default bearer is first created when a new PDN connection is created.
  • a service for example, the Internet, etc.
  • VoD for example, VoD, etc.
  • a dedicated bearer is created. In this case, the dedicated bearer may be set to a different QoS from the bearer that is already set.
  • QoS decision parameters applied to the dedicated bearer are provided by a Policy and Charging Rule Function (PCRF).
  • PCRF Policy and Charging Rule Function
  • the PCRF may receive subscription information of a user from a Subscriber Profile Repository (SPR) to determine QoS determination parameters.
  • SPR Subscriber Profile Repository
  • Up to 15 dedicated bearers may be created, for example, and four of the 15 are not used in the LTE system. Therefore, up to 11 dedicated bearers can be created.
  • the EPS bearer includes a QoS Class Identifier (QCI) and Allocation and Retention Priority (ARP) as basic QoS determination parameters.
  • EPS bearers are classified into GBR (Guaranteed Bit Rate) bearers and non-GBR bearers according to QCI resource types.
  • the default bearer is always a non-GBR type bearer, and the dedicated bearer may be set as a GBR type or non-GBR type bearer.
  • the GBR bearer has GBR and MBR (Maximum Bit Rate) as QoS decision parameters in addition to QCI and ARP.
  • small cells such as a pico cell, a femto cell and a wireless relay
  • data services for indoor and outdoor small areas can be operated.
  • pico cells are generally used in communication shaded areas that are not covered by macro cells alone, or in areas with high data service demands, so-called hot spots or hot zones.
  • a femto eNB is generally used in an indoor office or home.
  • the wireless relay can supplement the coverage of the macro cell.
  • FIG. 5 is a diagram schematically illustrating a concept of a heterogeneous network including a macro base station, a femto base station, and a pico base station according to the present invention.
  • FIG. 5 illustrates a heterogeneous network including a macro base station, a femto base station, and a pico base station for convenience of description
  • the heterogeneous network may include a micro, relay, or other type of base station.
  • the base station may include the aforementioned macro base station, femto base station, pico base station, micro base station, relay, and other types of base stations.
  • a macro base station 510, a femto base station 520, and a pico base station 530 are operated together in a heterogeneous network.
  • the macro base station 510, the femto base station 520, and the pico base station 530 each provide their cell coverage of the macro cell, femto cell, and pico cell to the terminal.
  • the femto base station 520 is a low power wireless access point, and is a micro mobile base station for indoor use such as a home or an office.
  • the femto base station 520 may access a mobile communication core network using a DSL or cable broadband of a home or office.
  • the femto base station 520 may be supported with a self-organization function. Self-organization functions are classified into a self-configuration function, a self-optimization function, and a self-monitoring function.
  • the types of pico cells provided by the pico base station 530 are "picocells for coverage holes” (hereinafter referred to as coverage hole picocells) and “picocells for hot spots” (hereinafter referred to as “hot spot picocells”). Is called.
  • the coverage hole picocell is used for the UE to transmit and receive data through the pico cell in place of the macro cell when the UE cannot transmit or receive data through the macro cell.
  • the hot spot picocell is capable of transmitting and receiving data through the macro cell, but is used for the terminal to transmit and receive data through the pico cell instead of the macro cell in order to reduce the load of the macro cell.
  • Hot spots can also refer to areas with a high concentration of floating or permanent population, or areas with very high demand traffic. In general, hot spot regions can occur regardless of the electro-magnetic field of the macro, where the pico cell is divided into two types: intra-frequency picocells and inter-frequency picocells. It can be divided into forms.
  • An intra-frequency pico cell refers to a picocell using the same frequency band as the macro cell. By reusing the same frequency resources in spatially separated areas, it is possible to secure the same radio resources as the macro cells within pico cell coverage.
  • the pico cell for most coverage holes corresponds to an intra-frequency pico cell.
  • Inter-frequency picocells are picocells that use a different frequency band than macro cells.
  • performance degradation may occur due to an interference problem between the pico cell and the macro cell. It can be used when there is a hot spot at a position close to the center of the macro cell.
  • a small cell serves a smaller area than the macro cell, it is advantageous to the macro cell in terms of throughput that can be provided for a single terminal.
  • the terminal connected to the macro cell is located in the service area of the small cell, the terminal cannot receive the service from the small cell without performing the handover.
  • handover may occur frequently because the coverage of the small cell is small, which is not preferable in terms of network efficiency.
  • FIG. 6 is a diagram illustrating a scenario to which the present invention is applied.
  • the scope of the present invention is not limited to the above scenario.
  • DRB data radio bearer
  • the small base stations 600 and 610 and the macro base station 650 are connected through the backhaul 605.
  • the ideal backhaul has a small latency of 2-5 ms, or the non-ideal backhaul connection is 25-. It can have a rather large delay of 60 ms.
  • the dually connected terminal may transmit and receive data from the macro base station through the DRB and simultaneously transmit and receive data to and from the first small base station 600.
  • the terminal transmits and receives data through the DRB of the macro cell and the DRB of the second small cell.
  • 6 is an example of a protocol stack constituting the scenario of FIG. 6.
  • a DRB 705 of a macro cell belonging to a terminal and a macro base station and an S1-bearer 710 of a macro base station and an S-GW are connected.
  • the DRB 715 of the small cell belonging to the terminal and the small base station and the S1-bearer 720 of the small base station and the S-GW are connected.
  • the E-RABs 705 and 710 using the macro base station and the E-RABs 715 and 720 of the small cell to which the small base station belongs belong to different EPS bearers.
  • the UE transmits and receives user data of the first EPS bearer through the macro cell, transmits and receives user data of the second EPB bearer through the small cell, and the first small cell and the second small cell are located within the coverage of the macro cell.
  • the terminal When the terminal moves from the first small cell area to the second small cell area, the terminal transmits and receives user data of the EPS bearer through the first small cell while maintaining transmission and reception of the user data of the first EPS bearer through the macro cell. Change the transmission and reception via the second small cell (eg, all or part of the EPS bearer).
  • the protocol stack of the macro cell includes the PDCP / RLC / MAC / PHY layer in the macro cell for the first EPS bearer, and the PDCP is included in the macro base station for the second EPS bearer and the RLC / MAC / PHY layer is small. It is included in the base station. PDCP and RLC are connected through the interface between the macro base station and the small base station.
  • PHY and MAC do not exist separately for different EPS bearers, but RLC and PDCP exist as separate instances.
  • FIG. 8 is a flowchart illustrating an example of a method of changing a DRB between small cells while maintaining a DRB with a macro cell according to the present invention.
  • the terminal transmits and receives user data to and from an external data network (eg, PDN) through a first small cell and a macro cell (S800).
  • PDN public data network
  • S800 macro cell
  • the macro base station shares the MAC / PHY information of the second small cell (S805). This is because the macro base station must know the MAC / PHY information of the second small cell in order for the macro base station to transmit the MAC / PHY information of the second small cell to the terminal.
  • the step S805 may be performed before S800 (S806).
  • step S805 may be performed after step S810, in the case of non-ideal backhaul having a large delay of the interface between the macro base station and the small base station, service interruption or delay may occur, resulting in deterioration of quality. This is of course possible in the case of an ideal backhaul with little delay.
  • the second small cell may periodically report its MAC / PHY information.
  • the second small cell may transmit the MAC / PHY information to the macro base station.
  • the MAC / PHY information of the second small cell may be transmitted to the macro base station at the request of the macro base station (eg, immediately after step S810) (S807).
  • the terminal reports the information related to the strength of the measured radio signal to the macro base station (S810).
  • the macro base station may determine to use the second small cell instead of the first small cell through the measurement report value.
  • the terminal may measure the strength of the radio signal and report related measurement information when an event such as a weak signal of the first small cell and a strong signal of the second small cell occurs.
  • the measurement report may be performed when the terminal determines that it is better to perform the service using the second small cell instead of the first small cell.
  • the macro base station transmits a re-configuration message to the terminal instructing to selectively re-establishment the DRB to be delivered from the first small cell to the second small cell (S815).
  • the re-configuration message may include re-establishment of a specific DRB of the PDCP / RLC of the UE when the cell is changed between the small cells overlapped with the macro cell. That is, re-establishment can be performed for the DRB which wants to continuously provide data transmission / reception service in the target small cell among the DRBs of one source small cell.
  • the UE should re-establishment all PDBs / RLCs of all DRBs owned by the UE, and transmit and receive data through the DRB to be subsequently provided from the source small cell to the target small cell.
  • the PDCP / RLC of all DRBs owned by the UE are re-established, and DRBs other than data transmission / reception belonging to the DRB which intends to continuously provide data transmission / reception in the target small cell (eg, DRB with macro cell) ) Is also re-establishment.
  • a problem may occur that the data transmission / reception service in the corresponding DRB is temporarily delayed.
  • the re-configuration is not only selective re-establishment of the DRB, but also configuration information of the MAC and PHY of the target small cell as configuration information of the MAC and PHY of the target small cell. Includes changes.
  • the macro base station may reconfigure the terminal by using one or more reconfiguration messages.
  • the reconfiguration message includes re-establishment of PDCP or RLC of all DRBs belonging to the first small cell among a plurality of DRBs to the UE.
  • the reconfiguration not only re-establishments the DRB but also changes the MAC and PHY configuration information of the source small cell to the configuration information of the MAC and PHY of the target small cell. It includes.
  • the re-configuration message includes re-establishment of PDCP or RLC for only some of the DRBs belonging to the first small cell among the plurality of DRBs.
  • the reconfiguration not only re-establishments the DRB but also changes the MAC and PHY configuration information of the source small cell to the configuration information of the MAC and PHY of the target small cell. It includes.
  • step S815 the UE performs PDCP or RLC re-establishment on the designated DRB among the allocated DRBs (S820).
  • the terminal transmits and receives user data to and from an external data network (PDN) via a macro cell through the second small cell (S825).
  • PDN external data network
  • the description of Figure 8 can be applied to the scenario when the mobile station to the data transmission and reception of the macro cell to the small cell overlapped with the macro cell, and also to the coverage of the same macro cell again in the small cell overlapped with the macro cell Can also be applied when moving.
  • the base station may inform the terminal of the cell information and the DRB mapping information in the corresponding cell by RRC signaling.
  • FIG. 9 is a flowchart illustrating an example of an operation of a terminal for changing a DRB between small cells according to the present invention.
  • the terminal transmits and receives user data with respect to an external data network (eg, PDN) through a first small cell and a macro cell (S900).
  • PDN public data network
  • the terminal reports the information related to the strength of the measured radio signal to the macro base station (S905).
  • the terminal measures the strength of the radio signal and reports relevant measurement information when an event such that the signal of the first small cell becomes weak and the signal of the second small cell becomes strong occurs.
  • the base station may determine that it is better to perform the service using the second small cell instead of the first small cell based on the measurement information.
  • the terminal receives a re-configuration message from the macro base station to selectively re-establishment the DRB of the second small cell (S910).
  • the reconfiguration not only re-establishments the DRB but also changes the MAC and PHY configuration information of the source small cell to the configuration information of the MAC and PHY of the target small cell. It includes.
  • the macro base station reconfigures the terminal using one or more reconfiguration messages.
  • the reconfiguration message includes re-establishment of PDCP or RLC of all DRBs belonging to the first small cell among a plurality of DRBs to the UE.
  • the reconfiguration not only re-establishments the DRB but also changes the MAC and PHY configuration information of the source small cell to the configuration information of the MAC and PHY of the target small cell. It includes.
  • the re-configuration message includes re-establishment of PDCP or RLC for only some of the DRBs belonging to the first small cell among the plurality of DRBs.
  • the terminal performs PDCP or RLC re-establishment on the designated DRB among the allocated DRBs (S915).
  • the terminal transmits and receives user data to and from an external data network (eg, PDN) via the macro cell through the second small cell (S920).
  • PDN public data network
  • FIG. 10 is a flowchart illustrating an example of an operation of a base station for changing a DRB between small cells while maintaining a DRB with a macro cell according to the present invention.
  • the macro base station shares MAC / PHY information of the second small cell (S1000). This is because the macro base station must know before setting the MAC and PHY information of the second small cell to the terminal.
  • the macro base station may periodically receive MAC / PHY information of the second small cell from the second small cell.
  • the macro base station may receive MAC / PHY information of the second small cell from the second small cell.
  • the macro base station may receive MAC / PHY information of the second small cell from the second small cell.
  • the macro base station receives information related to the strength of the radio signal measured by the terminal from the terminal (S1005).
  • the macro base station determines that the second small cell is used instead of the first small cell through the measurement report value (S1010).
  • the macro base station transmits a reconfiguration message to the terminal to selectively re-establishment the DRB to be transmitted from the first small cell to the second small cell (S1015).
  • the re-configuration message includes resetting the PDCP / RLC of the UE to a specific DRB only when the cell is changed between the macro cells and the small cells overlapping with each other. That is, re-establishment can be performed for the DRB which wants to continuously provide data transmission / reception service in the target small cell among the DRBs of one source small cell.
  • the MAC and PHY configuration information of the source small cell is changed to the configuration information of the MAC and PHY of the target small cell as well as the reconfiguration of the DRB. It includes.
  • the macro base station reconfigures the terminal using one or more reconfiguration messages.
  • the reconfiguration message includes re-establishment of PDCP or RLC of all DRBs belonging to the first small cell among a plurality of DRBs to the UE.
  • the reconfiguration not only re-establishments the DRB but also changes the MAC and PHY configuration information of the source small cell to the configuration information of the MAC and PHY of the target small cell. It includes.
  • the re-configuration message includes re-establishment of PDCP or RLC for only some of the DRBs belonging to the first small cell among the plurality of DRBs.
  • FIG. 11 is a block diagram illustrating an example of an apparatus for changing a DRB between small cells according to the present invention.
  • the terminal 1100 includes a receiver 1105, a controller 1110, or a transmitter 1120.
  • the controller 1110 may further include a measurement unit 1112 and a reset unit 1114.
  • the transmitter 1120 or the receiver 1105 transmits or receives user data to an external data network (eg, PDN) through the first small cell and the macro cell.
  • PDN public data network
  • the measuring unit 1112 performs the measurement.
  • the measurement unit 1112 may measure the strength of the radio signal to perform a measurement when an event such as a weak signal of the first small cell and a strong signal of the second small cell occurs.
  • the transmitter 1120 transmits the measurement report to the macro base station 1150 when it is determined that it is better to perform the service using the second small cell instead of the first small cell.
  • the receiver 1105 receives a reconfiguration message from the macro base station 1150 to selectively re-establishment the DRB of the second small cell.
  • the MAC and PHY configuration information of the source small cell is changed to the configuration information of the MAC and PHY of the target small cell as well as the reconfiguration of the DRB. It includes.
  • the reconfiguration message includes re-establishment of PDCP or RLC of all DRBs belonging to the first small cell among a plurality of DRBs to the terminal 1100.
  • the MAC and PHY configuration information of the source small cell is changed to the configuration information of the MAC and PHY of the target small cell as well as the reconfiguration of the DRB. It includes.
  • the reconfiguration message includes re-establishment of PDCP or RLC for only some of the DRBs belonging to the first small cell among the plurality of DRBs.
  • the reset unit 1114 performs PDCP or RLC re-establishment on the designated DRB among the allocated DRBs.
  • the transmitter 1120 or the receiver 1105 transmits or receives an external data network (eg, PDN) and user data via the macro cell through the second small cell.
  • an external data network eg, PDN
  • the base station 1550 includes a transmitter 1555, a receiver 1560, or a controller 1565.
  • the receiver 1560 receives MAC / PHY information of the small cell from the small base station.
  • the receiver 1560 may periodically receive MAC / PHY information of the small cell.
  • the receiver 1560 may receive the MAC / PHY information of the small cell when an event in which all or part of the MAC / PHY information of the small cell is changed.
  • the receiver 1560 may receive MAC / PHY information of the small cell at the request of the base station 1550.
  • the receiver 1560 receives information about the strength of the radio signal measured by the terminal from the terminal.
  • the controller 1565 determines to use the second small cell instead of the first small cell through the measurement report value.
  • the transmitter 1555 transmits a reconfiguration message to the terminal to selectively re-establishment the DRB to be delivered from the first small cell to the second small cell.
  • the re-configuration message may include re-establishment of the PDCP / RLC of the UE to a specific DRB provided only in the small cell when the cell is changed between the macro cells and the small cells overlapped with each other. do.
  • the MAC and PHY configuration information of the source small cell is changed to the configuration information of the MAC and PHY of the target small cell as well as the reconfiguration of the DRB. It includes.
  • the reconfiguration message includes re-establishment of PDCP or RLC of all DRBs belonging to the first small cell among a plurality of DRBs to the UE.
  • the re-configuration message includes re-establishment of PDCP or RLC for only some of the DRBs belonging to the first small cell among the plurality of DRBs.

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

Abstract

L'invention concerne un procédé de changement de cellule dans un système de communications sans fil de réseau hétérogène et un appareil associé. Le procédé selon la présente invention comprend les étapes permettant à un terminal : d'envoyer les informations de l'intensité d'un signal sans fil mesuré à une première station de base pour une macro cellule ; de recevoir un message de changement structurel pour réinitialiser sélectivement une DRB (porteuse radio de données) d'une seconde petite cellule provenant de la première station de base ; et de réinitialiser une couche PDCP ou RLC pour que la DRB bascule à une seconde petite cellule allouée dans les DRB allouées au terminal sur la base du message de changement structurel.
PCT/KR2014/003155 2013-04-12 2014-04-11 Procédé de changement de cellule dans un système de communications sans fil en réseau hétérogène et appareil associé Ceased WO2014168452A1 (fr)

Applications Claiming Priority (2)

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KR1020130040412A KR102049391B1 (ko) 2013-04-12 2013-04-12 이종 네트워크 무선 통신 시스템에서 셀 변경 방법 및 그 장치
KR10-2013-0040412 2013-04-12

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WO2014168452A1 true WO2014168452A1 (fr) 2014-10-16

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CN109964425B (zh) * 2016-11-01 2020-12-01 Lg电子株式会社 在无线通信系统中基于优先级的干扰控制方法及其装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20120036449A (ko) * 2010-10-08 2012-04-18 삼성전자주식회사 이기종 망 시스템에서 소형 셀의 커버리지 확장을 지원하기 위한 장치 및 방법
WO2012148203A2 (fr) * 2011-04-27 2012-11-01 엘지전자 주식회사 Procédé d'enregistrement et de notification d'informations de réseau hétérogène dans un système de communication sans fil et dispositif prenant en charge ce dernier
WO2013020292A1 (fr) * 2011-08-11 2013-02-14 Nokia Corporation Indication d'affectation pdsch pour une transmission ack/nack de scell fdd
WO2013024335A2 (fr) * 2011-08-17 2013-02-21 Alcatel Lucent Procédé et appareil pour commander l'exécution d'une configuration dynamique de ressources sur la liaison montante et sur la liaison descendante dans un réseau hétérogène

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20120036449A (ko) * 2010-10-08 2012-04-18 삼성전자주식회사 이기종 망 시스템에서 소형 셀의 커버리지 확장을 지원하기 위한 장치 및 방법
WO2012148203A2 (fr) * 2011-04-27 2012-11-01 엘지전자 주식회사 Procédé d'enregistrement et de notification d'informations de réseau hétérogène dans un système de communication sans fil et dispositif prenant en charge ce dernier
WO2013020292A1 (fr) * 2011-08-11 2013-02-14 Nokia Corporation Indication d'affectation pdsch pour une transmission ack/nack de scell fdd
WO2013024335A2 (fr) * 2011-08-17 2013-02-21 Alcatel Lucent Procédé et appareil pour commander l'exécution d'une configuration dynamique de ressources sur la liaison montante et sur la liaison descendante dans un réseau hétérogène

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