WO2014182110A1

WO2014182110A1 - Method and apparatus for radio connection control configuration in wireless communication system

Info

Publication number: WO2014182110A1
Application number: PCT/KR2014/004135
Authority: WO
Inventors: 권기범; 안재현; 허강석
Original assignee: 주식회사 팬택
Priority date: 2013-05-10
Filing date: 2014-05-09
Publication date: 2014-11-13
Also published as: KR20140133366A; KR102049392B1

Abstract

The present invention relates to a method and an apparatus for a radio connection control configuration in a wireless communication system. The present invention comprises: performing an RRC connection setup on a terminal through a macro cell; receiving a result of measuring, by the terminal, a small cell provided by a small base station from the terminal; transmitting a UP dual connectivity setup message to the small base station; receiving a UP dual connectivity completion message including RLC information configured by the small base station from the small base station; and transmitting an RRC re-configuration message configured on the basis of the RLC information to the terminal.

Description

Method and apparatus for configuring wireless connection control in wireless communication system

The present invention relates to wireless communication, and more particularly, to a method and apparatus for operating data in a radio connection control layer for a terminal dually connected to a plurality of base stations.

In particular areas, such as hot spots inside the cell, there is a great demand for communication, and in certain areas such as cell edges or coverage holes, the reception sensitivity of radio waves may be reduced. With the development of wireless communication technology, small cells, such as pico cells, within a macro cell for the purpose of enabling communication in areas such as hot spots, cell boundaries, and coverage holes. (Pico Cell), femto cell (Femto Cell), micro cell (Micro Cell), remote radio head (RRH), relay (relay), repeater (repeater) is installed together. Such a network is called a heterogeneous network (HetNet). 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.

The terminal may perform wireless communication through one or more base stations among the base stations configuring at least one serving cell. This is called dual connectivity. At this time, one of the plurality of physically or logically divided base stations is referred to as a central base station (or a macro base station or an anchor base station or a primary base station or a master base station). It may be referred to as a small base station (or a small base station or an assisting base station or a secondary base station).

The central base station manages data flow control and security according to the Packet Data Convergence Protocol (PDCP) for data transmitted to a small base station through a radio bearer (RB).

The radio link control (RLC) layer in the RB may be configured in the form of a sub-entity for each eNB or an entity for multiple eNBs. Can be. 1) The sub-entities for each base station are sub-entities defined in the RLC layer in the RB serviced by multiple base stations. The RLC layer may be used in a structure in which each base station is independently located. 2) An entity for a plurality of base stations is a single entity that resides in an RB serviced by multiple base stations. It can be used in a structure in which a master RLC layer is located in a central base station and a slave RLC layer is located in a small base station.

The small base station transmits data received from the PDCP layer or the master RLC layer in a single RB of the central base station to the terminal through the RLC layer or to the terminal through the slave RLC layer, MAC layer, and PHY layer. In this case, flow control for data in the RLC layer is different according to different RLC configuration information that can be defined in a plurality of base stations defined in the RB.

In the present invention, a method for exchanging related information between base stations is required to support different flow control schemes.

An object of the present invention is to provide a configuration method and apparatus for serving a terminal in a plurality of base stations.

Another object of the present invention is to provide a method and apparatus for configuring a wireless connection control layer for a dual connected terminal.

Another technical problem of the present invention is to provide a method and apparatus for transmitting information for configuring a wireless connection control layer for a dual connected terminal.

Another technical problem of the present invention is to provide a user plane dual connectivity setup method and apparatus for a dual connected terminal.

According to an aspect of the present invention, in a network system including a macro base station and a small base station, the method for configuring a radio connection control by the macro base station may include: performing RRC connection establishment for a terminal through a macro cell, wherein the terminal is configured to perform the small Receiving a measurement result for the small cell provided by the base station from the terminal, Transmitting an UP dual connectivity setup message to the small base station, UP dual connectivity complete message including the RLC information configured in the small base station Receiving from the small base station and transmitting the RRC reconfiguration message configured based on the RLC information to the terminal, wherein the UP dual connectivity setup message includes multi-flow ON / OFF information or RLC type information QoS information, and information of the macro base station.

According to another aspect of the present invention, in a network system including a macro base station and a small base station, the method for configuring wireless connection control by the small base station may include receiving an UP dual connectivity setup message from the macro base station, the UP dual connectivity setup message; Comprising a step of configuring the RLC for the terminal based on the step and transmitting the UP dual connectivity complete message including the configured RLC information to the macro base station, the UP dual connectivity setup message is the ON / OFF information of the multiflow Or include RLC type information, QoS information, and information of the macro base station.

According to the present invention, an RLC configuration can be performed, information can be exchanged between a plurality of base stations supporting different flow control schemes, and thus, dual connected terminals can be supported.

1 shows a wireless communication system to which the present invention is applied.

2 is a block diagram illustrating a radio protocol structure for a user plane.

3 is a block diagram illustrating a radio protocol architecture for a control plane.

4 is a diagram illustrating an outline of an example of an RLC sublayer model to which the present invention is applied.

5 shows an example of a dual connection situation of a terminal applied to the present invention.

6 to 8 illustrate an example in which a terminal establishes dual connectivity with a small base station and a macro base station.

9 to 12 illustrate examples of a dual connectivity scenario between the terminal and the base stations according to the presence type of the RRC layer. Scenarios in terms of the control plane.

13 is a flowchart illustrating a method of configuring a wireless connection control according to the present invention.

14 is a flowchart illustrating an example of an operation of a macro base station for configuring wireless connection control according to the present invention.

15 is a flowchart illustrating an example of an operation of a small base station configuring wireless connection control according to the present invention.

16 is a flowchart illustrating an example of an operation of a terminal that is dually connected according to the present invention.

17 is a block diagram illustrating an example of an apparatus for configuring wireless connection control according to the present invention.

Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings and examples, together with the contents of the present disclosure. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even though they are shown in different drawings. In addition, in describing the embodiments of the present specification, when it is determined that a detailed description of a related well-known configuration or function may obscure the gist of the present specification, the detailed description thereof will be omitted.

In addition, the present specification describes a wireless communication network, the operation performed in the wireless communication network is performed in the process of controlling the network and transmitting data in the system (for example, the base station) that is in charge of the wireless communication network, or the corresponding wireless Work may be done at the terminal coupled to the network.

1 shows a wireless communication system to which the present invention is applied. This may be a network structure of an Evolved-Universal Mobile Telecommunications System. The E-UMTS system may be a Long Term Evolution (LTE) or LTE-A (Advanced) system. 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 Various multiple access schemes such as OFDM, TDMA, and OFDM-CDMA may be used.

Referring to FIG. 1, the E-UTRAN provides a base station 20 (evolved NodeB: eNB) which provides a control plane (CP) and a user plane (UP) to a user equipment (UE). Include.

The terminal 10 may be fixed or mobile and may be called by other terms such as mobile station (MS), advanced MS (AMS), user terminal (UT), subscriber station (SS), and wireless device (Wireless Device). .

The base station 20 generally refers to a station communicating with the terminal 10, and includes a base station (BS), a base transceiver system (BTS), an access point, and a femto-eNB. It may be called other terms such as a pico base station (pico-eNB), a home base station (Home eNB), a relay (relay). The base stations 20 may be connected to each other through an X2 interface. The base station 20 is connected to a Serving Gateway (S-GW) through an MME (Mobility Management Entity) and an S1-U through an Evolved Packet Core (EPC) 30, more specifically, an S1-MME through an S1 interface. The S1 interface exchanges OAM (Operation and Management) information for supporting the movement of the terminal 10 by exchanging signals with the MME.

The EPC 30 includes an MME, an S-GW, and a packet data network-gateway (P-GW). The MME has access information of the terminal 10 or information on the capability of the terminal 10, and this information is mainly used for mobility management of the terminal 10. The S-GW is a gateway having an E-UTRAN as an endpoint, and the P-GW is a gateway having a PDN (Packet Data Network) as an endpoint.

Integrating the E-UTRAN and the EPC 30 may be referred to as an EPS (Evoled Packet System), and the traffic flows from the radio link that the terminal 10 connects to the base station 20 to the PDN connecting to the service entity are all IP. It works based on (Internet Protocol).

The air interface between the terminal and the base station is called a "Uu interface". The layers of the radio interface protocol between the terminal and the network are based on the lower three layers of the Open System Interconnection (OSI) reference model, which are well known in a communication system. It may be divided into a second layer L2 and a third layer L3. Among these, the physical layer belonging to the first layer provides an information transfer service using a physical channel, and the RRC (Radio Resource Control) layer located in the third layer exchanges an RRC message for the UE. Control radio resources between network and network.

FIG. 2 is a block diagram showing a radio protocol architecture for a user plane, and FIG. 3 is a block diagram showing a radio protocol architecture for a control plane. The user plane is a protocol stack for user data transmission, and the control plane is a protocol stack for control signal transmission.

2 and 3, a physical layer (PHY) layer provides an information transfer service to a higher layer using a physical channel. The physical layer is connected to a medium access control (MAC) layer, which is an upper layer, through a transport channel. Data is transmitted through a transport channel between the MAC layer and the physical layer. Transport channels are classified according to how data is transmitted over the air interface.

In addition, data is transmitted through a physical channel between different physical layers (ie, between physical layers of a transmitter and a receiver). The physical channel may be modulated by an orthogonal frequency division multiplexing (OFDM) scheme and utilizes time and frequency as radio resources.

For example, the physical downlink control channel (PDCCH) of the physical channel informs the UE 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. In addition, a physical control format indicator channel (PCFICH) informs the UE of the number of OFDM symbols used for PDCCHs and is transmitted every subframe. In addition, the PHICH (physical hybrid ARQ Indicator Channel) carries a HARQ ACK / NAK signal in response to uplink transmission. In addition, the physical uplink control channel (PUCCH) carries uplink control information such as HARQ ACK / NAK, scheduling request, and CQI for downlink transmission. In addition, a physical uplink shared channel (PUSCH) carries an uplink shared channel (UL-SCH).

The MAC layer may perform multiplexing or demultiplexing into a transport block provided as a physical channel on a transport channel of a MAC service data unit (SDU) belonging to the logical channel and mapping between the logical channel and the transport channel. The MAC layer provides a service to a Radio Link Control (RLC) layer through a logical channel. The logical channel may be divided into a control channel for transmitting control region information and a traffic channel for delivering user region information.

Functions of the RLC layer include concatenation, segmentation, and reassembly of RLC SDUs. 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).

The RLC SDUs are supported in various sizes, and for example, may be supported in units of bytes. RLC protocol data units (PDUs) are defined only when a transmission opportunity is notified from a lower layer (eg, MAC layer), and when the transmission opportunity is notified, the RLC PDUs are delivered to the lower layer. The transmission opportunity may be informed with the size of the total RLC PDUs to be transmitted. In addition, the transmission opportunity and the size of the total RLC PDUs to be transmitted may be separately reported. Hereinafter, the RLC layer will be described in detail with reference to FIG. 4.

Functions of the Packet Data Convergence Protocol (PDCP) layer in the user plane include delivery of user data, header compression, and ciphering. Functions of the PDCP layer in the user plane include 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). The SRB is used as a path for transmitting RRC messages and non-access stratum (NAS) messages in the control plane, and the DRB is used as a path for transmitting user data in the user plane.

The NAS layer is located above the RRC layer and performs functions such as session management and mobility management.

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.

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). Meanwhile, 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.

It is located above the transport channel, and the logical channel mapped to the transport channel is a broadcast control channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH), a multicast traffic (MTCH) Channel).

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. In addition, 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.

Referring to FIG. 4, certain RLC entities are classified into different RLC entities according to data transmission schemes. For example, there is a TM RLC entity 400, a UM RLC entity 420, and an AM RLC entity 440.

The UM RLC entity 400 may be configured to receive or forward RLC PDUs over logical channels (eg, DL / UL DTCH, MCCH or MTCH). In addition, the UM RLC entity may deliver or receive a UMD PDU (Unacknowledged Mode Data PDU).

The UM RLC entity consists of a sending UM RLC entity or a receiving UM RLC entity.

The transmitting UM RLC entity receives the RLC SDUs from the upper layer and sends the RLC PDUs to the peer receiving UM RLC entity via the lower layer. When the sending UM RLC entity constructs UMD PDUs from RLC SDUs, the total size of the RLC PDUs indicated by the lower layer by segmenting or concatenating the RLC SDUs when a specific transmission opportunity is notified by the lower layer. The UMD PDUs are configured to be within and the related RLC headers are included in the UMD PDU.

The receiving UM RLC entity delivers the RLC SDUs to the upper layer and receives the RLC PDUs from the peer receiving UM RLC entity through the lower layer. When the receiving UM RLC entity receives UMD PDUs, the receiving UM RLC entity detects whether the UMD PDUs have been received in duplicate, discards the duplicate UMD PDUs, and when the UMD PDUs are received out of sequence. Reorder the UMD PDUs, detect loss of UMD PDUs in the lower layer to avoid excessive reordering delays, reassemble RLC SDUs from the rearranged UMD PDUs, and In addition, the reassembled RLC SDUs are delivered to an upper layer in an ascending order of an RLC sequence number, and UMD PDUs cannot be reassembled into an RLC SDU due to a loss of UMD PDUs belonging to a specific RLC SDU in a lower layer. Can be discarded. Upon RLC re-establishment, the receiving UM RLC entity is able to reassemble the RLC SDUs from the received UMD PDUs, if possible, out of sequence and forward them to the higher layer, and remaining UMD PDUs that could not be reassembled into RLC SDUs. Discard all, initialize the relevant state variables and stop the associated timers.

Meanwhile, the AM RLC entity 440 may be configured to receive or deliver RLC PDUs through logical channels (eg, DL / UL DCCH or DL / UL DTCH). The AM RLC entity delivers or receives AMD PDUs or ADM PDU segments, and delivers or receives RLC control PDUs (eg, STATUS PDUs).

If a STATUS PDU is triggered and the t-StatusProhibit is not running or has expired, the STATUS PDU is sent at the next transmission opportunity. Accordingly, the UE estimates the size of the STATUS PDU and considers the STATUS PDU as data available for transmission in the RLC layer.

The AM RLC entity is composed of a transmitting side and a receiving side.

The transmitter of the AM RLC entity receives the RLC SDUs from the upper layer and sends the RLC PDUs to the peer AM RLC entity via the lower layer. When the transmitter of the AM RLC entity configures AMD PDUs from the RLC SDUs, it subdivides the RLC SDUs to fit within the total size of the RLC PDU (s) indicated by the lower layer when a particular transmission opportunity is notified by the lower layer. (segment) Concatenate to construct AMD PDUs. The transmitter of the AM RLC entity supports retransmission of RLC data PDUs (ARQ). If the RLC data PDU to be retransmitted does not fit within the total size of the RLC PDU (s) indicated by the lower layer when a particular transmission opportunity is informed by the lower layer, then the AM RLC entity retransmits the RLC data PDU into AMD PDU segments. Re-segment.

At this time, the number of re-segmentation is not limited. When the transmitter of the AM RLC entity creates AMD PDUs from RLC SDUs received from the upper layer or AMD PDU segments from RLC data PDUs to be retransmitted, the relevant RLC headers are included in the RLC data PDU.

The receiver of the AM RLC entity delivers the RLC SDUs to the upper layer and receives the RLC PDUs from the peer AM RLC entity via the lower layer.

When the receiver of the AM RLC entity receives the RLC data PDUs, it detects whether the RLC data PDUs have been received in duplicate, discards the duplicate RLC data PDUs, and receives the RLC data PDUs out of sequence. Reorder the order of RLC data PDUs, detect the loss of RLC data PDUs occurring in the lower layer, request retransmission to the peer AM RLC entity, and reassemble RLC SDUs from the rearranged RLC data PDUs. reassemble, and deliver the reassembled RLC SDUs to a higher layer in sequence.

When resetting the RLC, the receiver of the AM RLC entity, possibly out of sequence, reassembles the RLC SDUs from the received RLC data PDUs and delivers them to the higher layer, all remaining RLC data PDUs that cannot be reassembled into RLC SDUs. Discard it, initialize the relevant state variables and stop the associated timers.

The following table shows an example of functions supported by the RLC sublayer.

Table 1

Transfer of upper layer PDUs

Error correction through ARQ, but only for AM data transfer;

Concatenation, segmentation and reassembly of RLC SDUs, but only for UM and AM data transfer.

Re-segmentation of RLC data PDUs. Applies only to AM data transmission.

Reordering of RLC data PDUs. Applies only to UM and AM data transfers.

Duplicate detection. Applies only to UM and AM data transfers.

RLC SDU discard. Applies only to UM and AM data transfers.

RLC re-establishment

Protocol error detection. Applies only to AM data transmission.

Referring to FIG. 5, a terminal 550 located in a service area of a macro cell in a macro base station (or an anchor base station 500) may serve a small cell in a small base station (or assisting base station) 510. This is the case when entering an area over-laid with a region.

In order to support additional data service through the small cell provided by the small base station while maintaining the existing wireless connection and data service connection through the macro cell provided by the macro base station, the network configures dual connectivity to the terminal.

Accordingly, the user data arriving at the macro cell may be delivered to the terminal through the small cell in the small base station. Specifically, the F2 frequency band is assigned to the macro base station, and the F1 frequency band is assigned to the small base station. The terminal may receive a service through the F2 frequency band from the macro base station, and may receive a service through the F1 frequency band from the small base station.

6 to 8 illustrate an example in which a terminal establishes dual connectivity with a small base station and a macro base station. In particular, FIGS. 7 and 8 are multi-flow cases serving over macro base station and small base station in a single RB. The multiflow may be referred to as multiple node (eNB) transmission, inter-eNB carrier aggregation, or the like. Of course, the fact that multiflow is possible does not exclude the case of non-multiflow.

Referring to FIG. 6, the macro base station includes a PDCP, RLC, MAC, and PHY layer, while the small base station includes an RLC, MAC, and PHY layer.

The PDCP layer of the macro base station is connected to the RLC layer of the small base station using the Xn interface protocol through a backhaul. In this case, the Xn interface protocol may be an X2 interface protocol defined between base stations in the LTE system. Two PDCP layers exist only in the macro base station, and each PDCP layer is connected to a different RLC layer. In particular, the PDCP layer of the macro base station and the RLC layer of the small base station are connected to "# 2 RB".

The example of FIG. 6 is also called an independent RLC type or a single RLC entity type.

Referring to FIG. 7, the macro base station includes a PDCP, RLC, MAC, and PHY layer, whereas the small base station includes an RLC, MAC, and PHY layer.

The PDCP layer of the macro base station is connected to the RLC layer of the small base station using the Xn interface protocol over the backhaul. In this case, the Xn interface protocol may be an X2 interface protocol defined between base stations in the LTE system.

The PDCP layer of one macro base station is connected to both the RLC layer of the macro base station and the RLC layer of the small base station.

That is, the RLC layer of the macro base station is referred to as # 1 sub-entity, and the RLC layer of the small base station is referred to as # 2 sub-entity. Here, a sub-entity means that transmission and reception are divided into one-to-one matching. The RLC layer is in duplicate form. Each sub-entity is independent but there are two sub-entities (# 1 sub-entity and # 2 sub-entity) within one RB (ie # 1 RB).

In this case, RLC parameters should be configured separately for the RLC-AM # 1 sub-entity and the RLC-AM # 2 sub-entity, respectively. Because delay time that occurs when data serviced through each RLC-AM sub-entity is delivered to the UE may be different, timer values to be set in consideration of the delay time may be set for each sub-entity. This may be different from each other. If the delay times of data transmitted through each sub-entity are the same, values of timers to be set for each sub-entity may be the same. This may be determined at the macro base station and may be determined at the small base station, or may be determined at a network including the macro base station and the small base station. Thus, data to be delivered via PDCP in the same RB may be transmitted on one sub-entity of either an RLC-AM # 1 sub-entity or an RLC-AM # 2 sub-entity. Here, an identifier may be further transmitted by the terminal that receives the data to identify which sub-entity the data is transmitted through.

The example of FIG. 7 is also called a sub-entity RLC type in a multi-flow case. However, the example of FIG. 7 does not necessarily apply only to multiflow.

Referring to FIG. 8, the macro base station includes a PDCP, RLC, MAC, and PHY layers, while the small base station includes an RLC, MAC, and PHY layers. The RLC layer of the macro base station is connected to the RLC layer of the small base station using the Xn interface protocol over the backhaul.

The RLC layer of the small base station is connected to the RLC layer of the macro base station. Therefore, two base stations are controlled through one RB (that is, RB # 1). In this case, the RLC layer of the macro base station is called a master RLC layer, and the RLC layer of the small base station is called a slave RLC layer.

In the case of downlink, additional division is possible for the AMD / UM PDU of the slave RLC layer of the UE. The splitting operation of the slave RLC includes a grouping of a plurality of RLC PDUs or a grouping of AMD PDU segments divided in a master RLC. In addition, recombination of AMD / UM PDUs of a slave RLC layer of a base station is possible.

In the uplink, data received through the slave RLC layer is forwarded to the master RLC layer. If there is no data delivered to the slave RLC layer, the transmission between the terminal and the base station may be a single transmission instead of the TDM transmission.

The MAC scheduler is mainly responsible for scheduling radio resources, and the situation of the MAC layer of the macro base station is different from that of the small base station. The master RLC layer allocates (or splits, concatenates, or recombines) PDUs based on the MAC layer of the macro base station, and the slave RLC layer performs division or concatenation based on the MAC layer of the small base station.

In the uplink, only one RLC layer exists from the terminal's point of view. In downlink, since the MAC layer is different and a difference occurs in the radio situation, the UE is partitioned. In the uplink, a dual-connected terminal includes only one RLC layer. In this case, the slave RLC layer of the base station performs only a forwarding function and may perform uplink transmission only to the macro base station (also referred to as "single uplink"). In this case, ACK / NACK can also be transmitted only to the macro base station.

The example of FIG. 8 is also called a master-slave RLC type among multiflow cases. However, the example of FIG. 8 does not necessarily apply only to multiflow.

In the process of adding a serving cell through the small cell provided by the small base station, the DRB structure configuring the RLC layer for data transmission is possible. In the DRB structure, the RLC layer may have a UM mode and an AM mode. The UM mode is configured for real-time data transmission, such as data streaming or VoIP, and focuses on speed rather than data reliability. The AM mode focuses on data reliability, making it suitable for large data transmissions or data transmissions that are less sensitive to transmission delays.

The base station determines the mode (eg, UM mode or AM mode) of the RLC layer in the RB corresponding to the EPS bearer based on the QoS information of the EPS bearer and configures the parameters in the RLC to satisfy the QoS.

Referring to FIG. 9, (a) is the case where the RRC layer 900 exists only in the macro base station and the RRC signaling 910 is possible only through the macro cell provided by the macro base station. (b) is the case where the RRC layer 950 exists only in the macro base station, but the RRC signaling 960,970 is possible through the macro base station and the small base station. In this case, an RB (eg, SRB) configured for RRC reconfiguration may be supported through a multi-flow configuration.

Referring to FIG. 10, the RRC layer is present in the macro base station and the small base station. That is, the macro RRC layer 1000 exists in the macro base station, and the small RRC layer 1010 exists in the small base station. However, RRC signaling 1020 is possible only through the macro cell provided by the macro base station.

Referring to FIG. 11, the RRC layer is present in the macro base station and the small base station. That is, the macro base station has a macro RRC layer 1100, and the small base station has a small RRC layer 1110. However, the RRC signaling 1120 for the macro base station is possible only through the macro cell, and the RRC signaling 1130 for the small base station is possible only through the small cell.

Referring to FIG. 12, the RRC layer is present in the macro base station and the small base station. That is, the macro RRC layer 1200 exists in the macro base station, and the small RRC layer 1210 exists in the small base station.

Signaling

1230 and 1240 of RRC is a case where transmission is possible without macro cell or small cell discrimination.

In the configuration of the radio connection control of the dual-connected terminal, the structure of the transmission of the UP dual connectivity setup is different depending on which of the scenarios of FIG. 9 to FIG. 12 is applied.

For example, in FIG. 9A and FIG. 10, RRC signaling is impossible in the small base station, and in FIG. 11 and FIG. 12, RRC signaling is possible in the small base station.

In addition, the exchange of information between the macro base station and the small base station may be delivered in the form of multiflow (MF ON) or in the form of non-multiflow (MF OFF).

Now, a method and apparatus for configuring wireless connection control in a wireless communication system according to the present invention will be described. The present invention proposes a method and apparatus for configuring an RB corresponding to a one-to-one (1-to-1) EPS bearer between a base station (ie, a macro base station or a small base station) and a terminal.

According to the present invention, a terminal establishes a wireless connection for wireless communication through a macro cell provided by a macro base station, establishes dual connectivity with a macro cell provided by the macro base station, and a small cell provided by the small base station. It relates to the operation of the terminal and the base station has completed the RRC configuration to support the.

Referring to FIG. 13, the terminal establishes an RRC connection through a macro cell provided by the macro base station (S1300).

Subsequently to step S1300, when the terminal enters the service area of the small cell provided by the small base station, the terminal measures the small cell with the macro base station based on measurement report configuration information configured by the macro base station (eg, The result of performing the RRM measurement) is reported to the macro base station (S1305).

For example, the terminal may detect that the wireless connection is possible through the small cell provided by the small base station based on the measurement result.

Following step S1305, in order to configure dual connectivity of the terminal, the macro base station transmits an "UP dual connectivity setup message" to the small base station (S1310).

For example, the UP dual connectivity setup message may include 1) ON / OFF information of multiflow or 2) RLC type, QoS, and macro base station information.

As another example, when an UP dual connectivity setup message including information of the RLC type, QoS, and macro base station is delivered to the small base station, the small base station may be configured to implicitly know the ON / OFF information of the multiflow based on this. have.

As another example, when the UP dual connectivity setup message including the ON / OFF information of the multiflow is transmitted to the small base station, the small base station may be configured to know the remaining information based on this.

Meanwhile, the UP dual connectivity setup message may be transmitted even when an initial dual connectivity between base stations is configured for a specific terminal, and may be transmitted by a macro base station to a terminal having dual connectivity.

Alternatively, the CP dual connectivity setup message may include information for configuring an RRC layer for the small base station, and may include information for configuring a multiflow for the SRB2. If the CP dual connectivity setup message includes only information for configuring a multiflow for SRB2, the CP dual connectivity setup message may have the same format as the UP dual connectivity setup message.

As another example, the UP dual connectivity setup message may be transmitted simultaneously with the CP dual connectivity setup message for configuring the RRC layer to the small base station. For example, the CP dual connectivity setup message may include some or all of the UE context information, and the context information of the UE is a UE unique identifier (eg, C-RNTI) set by the macro base station. It may include a Cell-Radio Network Temporary Identifier, or may include UE characteristic information such as UE capability.

The CP duplex setup message is always included in the initial configuration of a duplex connection.

If the CP dual connectivity setup message and the UP dual connectivity setup message can be transmitted simultaneously, the message for the dual connectivity initial configuration may be referred to as a 'dual connectivity setup message'.

The UP dual connectivity setup message for other RBs may then be referred to as a 'dual connection reconfiguration message'.

The UP dual connectivity setup message may include only information on a single RB or may include information on a plurality of RBs. When the UP dual connectivity setup message includes information on a plurality of RBs, configuration information for each RB is independent of each other. For example, the first RB (RB # 1) may include information for configuring a multiflow (eg, MF ON). The second RB (RB # 2) related information may be simultaneously transmitted to the information about the first RB and may include information on RB flow reconfiguration (eg, MF OFF).

The following table is an example of information that may be included in the UP dual connectivity setup message. It is not necessary to include all fields of the table.

TABLE 2

Information	Remarks
Terminal identification indicator	For example, C-RNTI (Cell-RNTI)
Target Small Cell ID	For example, physical cell ID (PCI)
DRB ID	However, if the initial value of the DRB ID is set to SRB2 and the corresponding DRB ID is SRB2, there is no need to send it.
QoS for DRB	However, if the highest priority is set to SRB2 and the corresponding DRB is SRB2, no transmission is necessary.
MF ON / OFF	Indicates whether the multiflow of the RB is ON or OFF. Also known as a "multiflow indicator."
RLC type	Information indicating the entity structure of the corresponding RLC. The range of the RLC type can be defined in the form (0,1) or (0,2). It can be a 2-bit indicator. "If indicates sub-entity," 2 "indicates master-slave type. Alternatively, the range of RLC types can be defined in the form (0,1,2).
RLC configuration of the macro cell provided by the macro base station	1) If MF is ON, RRC reconfiguration message is sent through small base station for RB reconfiguration 2) Included only if it can be transmitted through RRC reconfiguration small base station or controlled at small base station

Here, the RLC type information is information indicating what the RLC type is. For example, the RLC type may be a single entity type as shown in FIG. 6, a sub-entity type as shown in FIG. 7, or a master-slave RLC type as shown in FIG. 8.

For example, if the RLC type is defined as "(0,1)", the RLC of the macro base station is a single entity and the RLC of the small base station is a sub-entity. Alternatively, when the RLC type is defined as "(0, 2)", the RLC of the macro base station is a single entity (master RLC) and the RLC of the small base station is a slave RLC.

In addition, the RLC configuration information may be an "RLC-Config" information element, and may include UL-AM-RLC, DL-AM RLC, UL-UM-RLC, or DL-UM-RLC. The UL-AM-RLC may include t-PollRetransmit, pollPDU, pollByte, or maxRetxThreshold. DL-AM-RLC may include t-Reordering or t-StatusProhibit. The UL-UM-RLC may include sn-FieldLength. The DL-UM-RLC may include sn-FieldLength or t-Reordering.

Each of the above parameters is defined as follows.

"t-PollRetransmit" defines the time to wait to retransmit a 'poll' sent for the purpose of triggering a STATUS report containing ACK / NACK information in a peer RLC AM entity. In this case, the 'pool' is a method of transmitting a 'p' bit in a specific RLC PDU to '1'.

"pollPDU / pollByte" are parameters for determining whether 'poll' can be included in a specific RLC PDU.

"maxRetxThreshold" is the maximum retransmission threshold. When the number of retransmissions for a specific RLC PDU reaches the threshold, the UE declares a radio link failure (RLF) and notifies the RRC layer thereof. Only defined in RLC AM mode.

"t-Reordering" is a parameter of a timer that defines a time to wait to perform reordering. "t-StatusProhibit" is a parameter of a timer that defines a time interval for prohibiting STATUS reporting.

The RLC configuration information of the macro cell provided by the macro base station may be included in the UP dual connectivity setup message only in the RRC signaling case as shown in FIG. 11 or 12. This is because, in the case of FIG. 9A or FIG. 10, RRC signaling is impossible in the small base station.

The following table is another example of information that may be included in the UP dual connectivity setup message, and indicates an Information Element (IE) type and a reference. It is not necessary to include all fields of the table.

TABLE 3

IE / Group Name	IE type and reference
C-RNTI	INTEGER (0..65536)
PCI	INTEGER (0..maxPCI)
EPS bearer ID	INTEGER (0..15)
DRB ID	INTEGER (0..31)
QCI	INTEGER (0..255)
RLC type	INTEGER (0..2)
Multi Flow ON / OFF	Boolean
RLC configuration information of the macro cell provided by the macro base station	RLC-config
GBR QoS Information	See Table 4

Referring to Table 3, the C-RNTI value may be replaced with a value such as a globally unique temporary identifier (GUTI), an international mobile subscriber identifier (IMSI), or an international mobile equipment identifier (IMEI). Alternatively, the C-RNTI value may not be duplicated in all terminals configured in the macro cell or the small cell.

The DRB ID value may be included if mandatory or optionally. That is, when the DRB is configured in the macro cell and the ID value of the DRB is set and then transmitted to the small cell, the DRB ID value is mandatory and transmitted. Alternatively, when the small cell can initially generate the DRB for the EPS bearer, the small cell may generate the DRB ID value and thus is selectively configured and transmitted. have.

Guaranteed Bit Rate (GBR) QoS information may be additionally transmitted when GBR configuration is required for the corresponding EPS bearer. The following table is an example of GBR QoS information, but does not have to include all fields of the table.

Table 4

IE / Group Name	IE type and reference	Semantics description
E-RAB Maximum Bit Rate Downlink	Bit rate	Maximum Bit Rate in DL (ie from EPC to E-UTRAN) for the bearer.
E-RAB Maximum Bit Rate Uplink	Bit rate	Maximum Bit Rate in UL (ie from E-UTRAN to EPC) for the bearer.
E-RAB Guaranteed Bit Rate Downlink	Bit rate	Guaranteed Bit Rate (provided that there is data to deliver) in DL (ie from EPC to E-UTRAN) for the bearer.
E-RAB Guaranteed Bit Rate Uplink	Bit rate	Guaranteed Bit Rate (provided that there is data to deliver) in UL (ie from E-UTRAN to EPC) for the bearer.

Referring to Table 4, "Bit Rate" refers to the number of bits transmitted by the base station in the uplink or the number of bits transmitted to the base station in the downlink for a predetermined period.

Subsequently to step S1310, the small base station configures an RLC in the small base station for the specific terminal based on the received UP dual connectivity setup message (S1315).

Subsequently to step S1315, the small base station transmits an UP dual connectivity complete message including the configured RLC information to the macro base station (S1320).

For example, if a small base station is capable of RRC signaling for the specific terminal (eg, in case of FIG. 11 or FIG. 12), since the small base station can directly transmit the RLC information to the terminal, the dual connectivity completion message is an RLC. May not contain information.

Following step S1320, the macro base station transmits an RRC reconfiguration message to the terminal (S1325). When the small base station cannot perform RRC signaling for the specific terminal as in the case of FIG. 9 (a) or FIG. 10, the macro base station transmits an RRC reconfiguration message including the RLC information received from the small base station to the terminal. do.

On the contrary, if the small base station is capable of RRC signaling for the specific terminal (eg, in case of FIG. 11 or FIG. 12), the small base station transmits RLC information configured in the macro base station through an UP dual connectivity setup message. The RRC reconfiguration message, which is received from the macro base station and includes the RLC information, may be directly transmitted to the specific terminal (not shown). Alternatively, the small base station may directly transmit an RRC reconfiguration message including only RLC configuration information to the specific terminal.

Subsequently to step S1325, the terminal dually connected through RRC reconfiguration receives a data service through a small cell (S1330).

Referring to FIG. 14, the macro base station performs RRC connection establishment for a terminal through a macro cell (S1400).

Subsequently to step S1400, the macro base station receives a result of performing measurement (for example, RRM measurement) for the small cell from the terminal entering the service area of the small cell provided by the small base station (S1405).

Subsequently to step S1405, in order to configure the dual connectivity of the terminal, the macro base station transmits an "UP dual connectivity setup message" to the small base station (S1410).

For example, the UP dual connectivity setup message may include 1) ON / OFF information of the multiflow or 2) information of the RLC type, QoS, and macro base station. Multiflow ON / OFF may be a 1-bit multiflow indicator.

As another example, the UP dual connectivity setup message may include at least one of the fields of Table 2 or Table 3.

Subsequently to step S1410, the macro base station receives an UP dual connectivity complete message including the RLC information configured in the small base station from the small base station (S1415).

Following step S1415, the macro base station transmits an RRC reconfiguration message to the terminal (S1420).

As an example (eg, in case of FIG. 9A or FIG. 10), if the small base station is unable to perform RRC signaling for the specific UE, the macro base station may perform RRC reconfiguration including RLC information received from the small base station. Send a message to the terminal.

Referring to FIG. 15, in order to configure dual connectivity of the terminal, the small base station receives an "UP dual connectivity setup message" from the macro base station (S1500).

In this case, when the UP dual connectivity setup message including the RLC type, QoS, and macro base station information is transmitted to the small base station, the small base station may be configured to implicitly know the ON / OFF information of the multiflow based on this. .

Alternatively, when the UP dual connectivity setup message including the ON / OFF information of the multiflow is transmitted to the small base station, the small base station may be configured to know the remaining information based on this.

Following step S1500, the small base station configures an RLC in the small base station for the specific terminal based on the received UP dual connectivity setup message (S1505).

Subsequently to step S1505, the small base station transmits an UP dual connectivity complete message including the configured RLC information to the macro base station (S1510).

However, when the small base station is capable of RRC signaling for the specific terminal (eg, in case of FIG. 11 or FIG. 12), the small base station may macro RLC information configured in the macro base station through an UP dual connectivity setup message. Received from the base station, the RRC reconfiguration message including the RLC information can be sent directly to the specific terminal. Alternatively, the small base station may directly transmit an RRC reconfiguration message including only RLC configuration information to the specific terminal. In this case, the dual connection complete message may not include RLC information.

Subsequently to step S1510, the small base station provides a data service through the small cell to the dually connected terminal through the RRC reconfiguration (S1515).

Referring to FIG. 16, the terminal establishes an RRC connection through a macro cell provided by a macro base station (S1600).

After step S1600, when the terminal enters the service area of the small cell provided by the small base station, the terminal measures the small cell with the macro base station based on the measurement report configuration information configured by the macro base station (eg, RRM measurement). The result of the operation is reported to the macro base station (S1605).

Following step S1605, the terminal receives an RRC reconfiguration message from the macro base station (S1610).

For example, if a small base station is capable of RRC signaling for the specific terminal (eg, in case of FIG. 11 or FIG. 12), the RRC reconfiguration message may not include RLC information.

In another example (eg, FIG. 9 (a) or FIG. 10), if the small base station cannot perform RRC signaling for the specific terminal, the RRC reconfiguration message includes RLC information transmitted by the small base station to the macro base station. do.

Subsequently to step S1610, a terminal dually connected through RRC reconfiguration receives a data service through a small cell (S1615).

Referring to FIG. 17, the terminal 1700 may include a terminal receiver 1705, a terminal processor 1710, or a terminal transmitter 1715.

The terminal receiver 1705 is configured for RRC connection through a macro cell in the macro base station 1730.

When the terminal 1700 enters the service area of the small cell in the small base station 1760, the terminal processor 1710 may measure the small cell based on the measurement report configuration information configured in the macro base station 1730 (eg, RRM measurement), and the terminal transmitter 1715 reports the measurement result to the macro base station 1730.

For example, the terminal processor 1710 may detect that the wireless connection is possible through the small cell in the small base station 1760 based on the measurement result.

The terminal receiver 1705 receives an RRC reconfiguration message from the macro base station 1730.

After the terminal 1700 is dually connected through RRC reconfiguration, the terminal receiver 1705 receives a data service through a small cell.

Meanwhile, the macro base station 1730 may include a macro receiver 1735, a macro processor 1740, or a macro transmitter 1745.

The macro transmitter 1745 performs RRC connection establishment for the terminal 1700 through the macro cell.

The macro receiver 1735 receives a result of performing a measurement (eg, RRM measurement) for the small cell from the terminal 1700 (S1405).

The macro transmitter 1745 transmits an "UP dual connectivity setup message" to the small base station 1760.

For example, the UP dual connectivity setup message may include 1) ON / OFF information of the multiflow or 2) information of the RLC type, QoS, and macro base station. Multiflow ON / OFF may be a 1-bit multiflow indicator. As another example, the UP dual connectivity setup message may include at least one of the fields of Table 2 or Table 3.

The macro receiver 1735 receives the UP dual connectivity complete message including the RLC information configured in the small base station 1760 from the small base station 1760.

The macro transmitter 1745 transmits an RRC reconfiguration message to the terminal 1700.

Meanwhile, the small base station 1760 may include a small receiver 1765, a small processor 1710, or a small transmitter 1175.

The small receiver 1765 receives an "UP dual connectivity setup message" from the macro base station 1730.

When the small receiver 1765 receives the UP dual connectivity setup message including information of the RLC type, QoS, and macro base station, the small processor 1770 may determine ON / OFF information of the multiflow based on the UP dual connectivity setup message.

Alternatively, when the small receiver 1765 receives the UP dual connectivity setup message including the ON / OFF information of the multiflow, the small processor 1770 based on the remaining information (eg, RLC type, QoS, and macro base station information) based on the UP dual connectivity setup message. ) Can be determined.

The small processor 1770 configures an RLC in the small base station for the specific terminal based on the UP dual connectivity setup message.

The small transmitter 1175 transmits the UP dual connectivity complete message including the configured RLC information to the macro base station 1730.

For example, when the small base station 1760 is capable of RRC signaling for the specific terminal (eg, in the case of FIG. 11 or FIG. 12), the small transmitter 1675 may directly transfer the RLC information to the terminal 1700. Can be. In this case, the dual connection complete message may not include RLC information.

The small transmitter 1175 provides a data service through the small cell to the dually connected terminal 1770 through RRC reconfiguration.

In the exemplary system described above, the methods are described based on a flowchart as a series of steps or blocks, but the invention is not limited to the order of steps, and certain steps may occur in a different order or concurrently with other steps than those described above. Can be. In addition, those skilled in the art will appreciate that the steps shown in the flowcharts are not exclusive and that other steps may be included or one or more steps in the flowcharts may be deleted without affecting the scope of the present invention.

The above-described embodiments include examples of various aspects. While not all possible combinations may be described to represent the various aspects, one of ordinary skill in the art will recognize that other combinations are possible. Accordingly, the invention is intended to embrace all other replacements, modifications and variations that fall within the scope of the following claims.

Claims

In a network system including a macro base station (Macro eNB) and a small base station (Small eNB) in the radio link control (Radio Link Control) configuration method by the macro base station,

Performing radio resource control (RRC) connection establishment with respect to a terminal through a macro cell;

Receiving, from the terminal, a result of the measurement performed by the terminal with respect to the small cell provided by the small base station;

Sending a UP Plane dual connectivity setup message to the small base station;

Receiving, from the small base station, an UP dual connectivity complete message including the RLC information configured by the small base station; And

Transmitting an RRC reconfiguration message configured based on the RLC information to the terminal;

The UP dual connectivity setup message includes on / off information of multiflow or RLC type information, quality of service (QoS) information, and information of the macro base station.
The method of claim 1, wherein the multiflow ON / OFF information is

And a 1-bit indicator indicating whether the information exchange between the macro base station and the small base station is a multiflow type which is serviced by a single radio bearer (RB).
The method of claim 2,

And the RRC reconfiguration message includes RLC information configured in the small base station only when the multiflow ON / OFF information indicates ON.
The method of claim 1,

If the small base station can transmit the RRC signaling to the terminal, the UP dual connectivity setup message further comprises the RLC configuration information of the macro cell.
The method of claim 1, wherein the UP dual connectivity setup message is

And a terminal identification indicator, a target small cell ID, a data radio bearer (DRB) ID, or RLC type information.
The method of claim 5,

The RLC type information is information indicating an entity structure of an RLC configured in the small base station.

Characterized in that it is in the form of an ordered pair consisting of two elements.
The method of claim 6,

And wherein the RLC type information is in the form of an ordered pair consisting of two of a single RLC entity, an RLC sub-entity, or a master-slate RLC entity.
In a network system including a macro base station (Macro eNB) and a small base station (Small eNB), a method for configuring a radio link control (RLC) by the small base station,

Receiving an UP dual connectivity setup message from the macro base station;

Configuring an RLC for a terminal based on the UP dual connectivity setup message; And

Transmitting a UP dual connectivity complete message including the configured RLC information to the macro base station,

The UP dual connectivity setup message includes ON / OFF information of multiflow or RLC type information, QoS information and information of the macro base station.
The method of claim 8,

If the terminal is dually connected through RRC reconfiguration of the macro base station, providing a data service to the terminal through a small cell.
The method of claim 8,

Determining ON / OFF information of the multiflow based on the RLC type information included in the UP dual connectivity setup message, the QoS and the information of the macro base station.
The method of claim 8,

Determining the RLC type information, the QoS and the information of the macro base station based on the ON / OFF information of the multiflow included in the UP dual connectivity setup message.
In a macro base station for configuring a Radio Link Control (RLC) in a network system including a macro base station (Macro eNB) and a small base station (Small eNB),

A macro processor for performing radio resource control (RRC) connection establishment with respect to a terminal through a macro cell;

A macro receiver configured to receive a result of the measurement performed by the terminal on the small cell provided by the small base station from the terminal, and to receive an UP dual connectivity completion message including the RLC information configured in the small base station from the small base station ; And

Including a macro transmitter for transmitting an UP dual connectivity setup (User Plane dual connectivity setup) message to the small base station, and transmits an RRC reconfiguration message configured based on the RLC information to the terminal,

The UP dual connectivity setup message includes on / off information of multiflow or includes RLC type information, quality of service (QoS) information, and information of the macro base station.
The method of claim 12, wherein the multiflow ON / OFF information is

And a 1-bit indicator indicating whether the information exchange between the macro base station and the small base station is a multiflow type which is serviced by a single radio bearer (RB).
The method of claim 13,

And the RRC reconfiguration message includes RLC information configured in the small base station only when the multiflow ON / OFF information indicates ON.
The method of claim 12,

If the small base station can transmit the RRC signaling to the terminal, the UP dual connectivity setup message further comprises the RLC configuration information of the macro cell.
In the small base station configuring the radio link control (RLC) in a network system including a macro base station (Macro eNB) and a small base station (Small eNB),

A small receiver configured to receive an UP dual connectivity setup message from the macro base station;

A small processor configured to configure an RLC for a terminal based on the UP dual connectivity setup message; And

It includes a small transmission unit for transmitting to the macro base station a UP dual connection complete message including the configured RLC information,

The UP dual connectivity setup message may include ON / OFF information of multiflow or RLC type information, QoS information, and information of the macro base station.
The method of claim 16,

If the terminal is dually connected through RRC reconfiguration of the macro base station,

The small base station, characterized in that for transmitting a data service to the terminal via a small cell.
The method of claim 16,

And the small processor determines ON / OFF information of the multiflow based on the RLC type information, the QoS, and the information of the macro base station included in the UP dual connectivity setup message.
The method of claim 16,

The small processor determines the RLC type information, the QoS and the information of the macro base station based on the ON / OFF information of the multiflow included in the UP dual connectivity setup message.