WO2018030776A1 - Method and apparatus for supporting mbms service continuity - Google Patents

Abstract

Provided are a method for supporting multimedia broadcast multicast service (MBMS) service continuity by a terminal in a wireless communication system and an apparatus supporting the same. The method may comprise the steps of: entering an RRC state in which cell reselection is not supported; determining whether an MBMS service of interest can be received at a serving frequency for the terminal; and when it is determined that the MBMS service of interest cannot be received at the serving frequency, transmitting an MBMS interest indication message to a network, wherein the terminal may be a terminal not supporting a handover.

Description

Method and device to support MBMS service continuity

The present invention relates to a wireless communication system, and more particularly, to a method for supporting a multimedia broadcast multicast service (MBMS) service continuity for a terminal and an apparatus for supporting the same.

The 3rd Generation Partnership Project (3GPP) long term evolution (LTE), an enhancement to the Universal Mobile Telecommunications System (UMTS), is being introduced as a 3GPP release 8. 3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in downlink and single carrier-frequency division multiple access (SC-FDMA) in uplink. A multiple input multiple output (MIMO) with up to four antennas is employed. Recently, a discussion on 3GPP LTE-Advanced (LTE-A), an evolution of 3GPP LTE, is underway.

MBMS (Multimedia Broadcast / Multicast Service) is a service that transmits data packets to multiple users at the same time similarly to the existing CBS (Cell Broadcast Service). However, while CBS is a low-speed message-based service, MBMS is intended for high-speed multimedia data transmission. In addition, CBS is not based on IP (internet protocol), but MBMS is based on IP multicast. According to the MBMS, when a certain level of users exist in the same cell, the users can receive the same multimedia data using a shared resource (or channel), thereby increasing the efficiency of radio resources and allowing users to value multimedia services. It is available cheaply.

MBMS uses a shared channel to efficiently receive data from a plurality of terminals in one service. For one service data, the base station does not allocate a dedicated channel as many as the number of terminals to receive the service in one cell, but allocates only one shared channel. In addition, since a plurality of terminals simultaneously receive the shared channel, the efficiency of radio resources is increased. In relation to the MBMS, the terminal may receive the MBMS after receiving system information about the corresponding cell.

Important communication technologies such as public safety and Group Communication System Enablers for LTE (GCSE_LTE) were introduced at Rel-12. In Rel-12 GCSE, group communication was designated as eMBMS. The eMBMS is designed to deliver media content to a wide range of preplanned areas (ie, MBSFN areas). The MBSFN area is rather static (eg set by O & M) and cannot be dynamically adjusted according to user distribution. Although all radio resources in the frequency domain are not used, eMBMS transmission occupies the entire system bandwidth and unicast and multiplexing are not allowed in the same subframe. The MBSFN subframe setting is also rather static (eg, set by O & M). That is, the MBSFN subframe cannot be dynamically adjusted according to the number of dynamic groups and the traffic load of the dynamic groups. Thus, when providing important communication services, radio resource setup for eMBMS can be wasted unnecessary. Therefore, Single-Cell Point-to-Multipoint transmission has been proposed for efficient use of radio resources. While MBSFN transmissions transmit identifiable signals in multiple cells simultaneously, SCPTM transmissions carry MBMS services in a single cell.

In recent years, M2M / IoT, which connects everything around us through a network, can easily acquire and deliver necessary information anytime, anywhere, and enables various services to be provided and used. It is highlighted.

Initially, M2M originated from sensor and RFID networks mainly targeting local areas, but various wired / wireless networks can be used as the purpose and characteristics of applications gradually increase. In recent years, the mobile communication network has been developed in consideration of the wide range of service areas including mobility of objects, islands and mountains as well as the ocean, ease of operation and maintenance of the network, security for reliable data transmission, and guarantee of service quality. There is a growing interest in M2M. As a reflection of this, 3GPP has started the feasibility study for M2M in 2005, and has been in full-fledged standardization since 2008 under the name of "Machine Type Communications (MTC)."

From 3GPP point of view, a machine is an entity that does not require human intervention or intervention, and MTC is defined as a form of data communication in which one or more of these machines are included. As a typical example of a machine, a form of a smart meter or vending machine equipped with a mobile communication module is mentioned, but recently, a smart phone that automatically connects to a network and performs communication without user intervention or intervention according to the user's location or situation. With the advent of the mobile terminal with the MTC function is also considered as a form of machine. In addition, a gateway-type MTC device connected to an IEEE 802.15 WPAN-based micro sensor or RFID is also considered.

The Internet of Things (IoT) is the future infrastructure and service of future information and communication where all things are connected to the Internet and communicate directly with each other. The reason why the Internet of Things is needed is to improve the quality of life and productivity based on a hyper-connected society, but ultimately it is important because it forms the central nervous system for the nation's own infrastructure, and furthermore, for humanity and the earth. The Internet of Things is the beginning of a notable big profit model yet, but the future market size of IoT, a new paradigm for the 21st century, is expected to grow more than 10 times compared to the existing cellular telecommunications market. The IoT is largely divided into cellular mobile communication based IoT (CIoT) and non-cellular based IoT.

Meanwhile, some terminals may not support handover as well as measurement report. Even if a UE that does not support measurement report and handover transmits an MBMS interest indication message to the network, the network cannot handover the UE to a frequency providing an MBMS service of interest. That is, the existing MBMS service continuity mechanism based on the MBMS interest indication message cannot provide the MBMS service continuity to terminals that do not support the measurement report or the handover. Accordingly, there is a need to propose a method for providing MBMS service continuity to terminals that do not support measurement reporting or handover and an apparatus supporting the same.

According to an embodiment, a method for supporting a multimedia broadcast multicast service (MBMS) service continuity in a wireless communication system is provided. The method includes entering an RRC state that does not support cell reselection; Determining whether an MBMS service of interest can be received from a serving frequency of the terminal; And if it is determined that the MBMS service of interest cannot be received from the serving frequency, transmitting an MBMS interest indication message to a network, wherein the terminal supports handover. It may be a terminal that does not.

The method may further include receiving an RRC connection release message from the network in response to the transmitted MBMS interest indication message. The method may further include entering an RRC_IDLE state in response to the received RRC connection release message. The method may further include performing cell reselection to a neighbor cell providing the MBMS service of interest. The method may further include receiving the MBMS service of interest from the reselected neighbor cell. The MBMS service of interest may be received via MBSFN transmission or SCPTM transmission.

The method comprises: receiving a system information block from the serving frequency after entering the RRC_IDLE state; And determining a neighbor cell providing the interested MBMS service based on the system information block. The method may further include considering at least one cell having a cell quality exceeding a threshold value among neighboring cells providing the MBMS service of interest as a target cell for cell reselection. The threshold may be received from the serving frequency. The cell quality may be at least one of RSRP or RSRQ. The method may further include performing a cell reselection procedure on the at least one target cell considered.

The method may further include considering at least one cell satisfying a cell selection criterion S (S) as a target cell for cell reselection among neighboring cells providing the MBMS service of interest. .

The network may be a radio access technology (RAT) that does not support handover.

The terminal may be at least one of an NB-IoT terminal, a CIoT terminal, an IoT terminal, or an eMTC terminal.

In another embodiment, a terminal supporting multimedia broadcast multicast service (MBMS) service continuity in a wireless communication system is provided. The terminal includes a memory; Transceiver; And a processor connecting the memory and the transceiver, wherein the processor enters an RRC state that does not support cell reselection and determines whether to receive an MBMS service of interest from a serving frequency of the terminal, If it is determined that the MBMS service of interest cannot be received from the serving frequency, the transceiver controls to send an MBMS interest indication message to the network, but the terminal supports a handover. It may not be a terminal.

A terminal that does not support measurement report or handover may receive an MBMS service of interest.

1 shows a structure of an LTE system.

2 shows a network structure for MBMS.

3 shows an air interface protocol of an LTE system for a control plane and a user plane.

4 shows an example in which system information and MBMS interest indication message for an MBMS service are transmitted.

5 shows an example of IoT communication.

6 and 7 illustrate an example of a narrow band in which an IoT device operates.

FIG. 8 illustrates a procedure in which a terminal supports MBMS service continuity based on an MBMS interest indication message according to an embodiment of the present invention.

9 illustrates a procedure of performing cell reselection by a UE in an RRC_IDLE state according to an embodiment of the present invention.

10 is a block diagram illustrating a method of supporting an MBMS service continuity by a terminal according to an embodiment of the present invention.

11 is a block diagram of a wireless communication system in which an embodiment of the present invention is implemented.

The following techniques include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and the like. It can be used in various wireless communication systems. CDMA may be implemented with a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented with wireless technologies such as global system for mobile communications (GSM) / general packet radio service (GPRS) / enhanced data rates for GSM evolution (EDGE). OFDMA may be implemented by wireless technologies such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, evolved UTRA (E-UTRA), and the like. IEEE 802.16m is an evolution of IEEE 802.16e and provides backward compatibility with systems based on IEEE 802.16e. UTRA is part of a universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is part of evolved UMTS (E-UMTS) using evolved-UMTS terrestrial radio access (E-UTRA), which employs OFDMA in downlink and SC in uplink -FDMA is adopted. LTE-A (advanced) is the evolution of 3GPP LTE.

For clarity, the following description focuses on LTE-A, but the technical spirit of the present invention is not limited thereto.

1 shows a structure of an LTE system. Communication networks are widely deployed to provide various communication services such as IMS and Voice over internet protocol (VoIP) over packet data.

Referring to FIG. 1, an LTE system structure includes one or more UEs 10, an evolved-UMTS terrestrial radio access network (E-UTRAN), and an evolved packet core (EPC). The terminal 10 is a communication device moved by a user. The terminal 10 may be fixed or mobile and may be called by other terms such as a mobile station (MS), a user terminal (UT), a subscriber station (SS), and a wireless device.

The E-UTRAN may include one or more evolved node-eB (eNB) 20, and a plurality of terminals may exist in one cell. The eNB 20 provides an end point of a control plane and a user plane to the terminal. The eNB 20 generally refers to a fixed station communicating with the terminal 10, and may be referred to in other terms such as a base station (BS), a base transceiver system (BTS), an access point, and the like. . One eNB 20 may be arranged per cell. There may be one or more cells within the coverage of the eNB 20. One cell may be configured to have one of bandwidths such as 1.25, 2.5, 5, 10, and 20 MHz to provide downlink (DL) or uplink (UL) transmission service to various terminals. In this case, different cells may be configured to provide different bandwidths.

Hereinafter, DL means communication from the eNB 20 to the terminal 10, and UL means communication from the terminal 10 to the eNB 20. In the DL, the transmitter may be part of the eNB 20 and the receiver may be part of the terminal 10. In the UL, the transmitter may be part of the terminal 10 and the receiver may be part of the eNB 20.

The EPC may include a mobility management entity (MME) that serves as a control plane, and a system architecture evolution (SAE) gateway (S-GW) that serves as a user plane. The MME / S-GW 30 may be located at the end of the network and is connected to an external network. The MME has information about the access information of the terminal or the capability of the terminal, and this information may be mainly used for mobility management of the terminal. S-GW is a gateway having an E-UTRAN as an endpoint. The MME / S-GW 30 provides the terminal 10 with the endpoint of the session and the mobility management function. The EPC may further include a packet data network (PDN) -gateway (GW). PDN-GW is a gateway with PDN as an endpoint.

The MME includes non-access stratum (NAS) signaling to the eNB 20, NAS signaling security, access stratum (AS) security control, inter CN (node network) signaling for mobility between 3GPP access networks, idle mode terminal reachability ( Control and execution of paging retransmission), tracking area list management (for terminals in idle mode and active mode), P-GW and S-GW selection, MME selection for handover with MME change, 2G or 3G 3GPP access Bearer management, including roaming, authentication, and dedicated bearer settings, SGSN (serving GPRS support node) for handover to the network, public warning system (ETWS) and commercial mobile alarm system (PWS) It provides various functions such as CMAS) and message transmission support. S-GW hosts can be based on per-user packet filtering (eg, through deep packet inspection), legal blocking, terminal IP (Internet protocol) address assignment, transport level packing marking in DL, UL / DL service level charging, gating and It provides various functions of class enforcement, DL class enforcement based on APN-AMBR. For clarity, the MME / S-GW 30 is simply represented as a "gateway", which may include both MME and S-GW.

An interface for user traffic transmission or control traffic transmission may be used. The terminal 10 and the eNB 20 may be connected by the Uu interface. The eNBs 20 may be interconnected by an X2 interface. Neighboring eNBs 20 may have a mesh network structure by the X2 interface. The eNBs 20 may be connected with the EPC by the S1 interface. The eNBs 20 may be connected to the EPC by the S1-MME interface and may be connected to the S-GW by the S1-U interface. The S1 interface supports a many-to-many-relation between eNB 20 and MME / S-GW 30.

The eNB 20 may select for the gateway 30, routing to the gateway 30 during radio resource control (RRC) activation, scheduling and transmission of paging messages, scheduling channel information (BCH), and the like. Perform connection mobility control in transmission, dynamic allocation of resources from the UL and DL to the terminals 10, configuration and provisioning of eNB measurements, radio bearer control, radio admission control (RAC) and LTE activation can do. As mentioned above, the gateway 30 may perform paging initiation, LTE idle state management, user plane encryption, SAE bearer control, and encryption and integrity protection functions of NAS signaling in the EPC.

2 shows a network structure for a multimedia broadcast / multicast service (MBMS).

Referring to FIG. 2, a radio access network (E-UTRAN) 200 includes a multi-cell coordination entity (hereinafter referred to as MCE, 210) and a base station (eNB) 220. The MCE 210 is a main entity controlling the MBMS, and serves as session management, radio resource allocation, or admission control of the base station 220 in the MBSFN region. . The MCE 210 may be implemented in the base station 220 or may be implemented independently of the base station 220. The interface between the MCE 210 and the base station 220 is called an M2 interface. The M2 interface is an internal control plane interface of the wireless access network 200, and MBMS control information is transmitted. If the MCE 210 is implemented in the base station 220, the M2 interface may only exist logically.

An Evolved Packet Core (EPC) 250 includes an MME 260 and an MBMS Gateway (MBMS GW) 270. The MBMS gateway 270 is an entity that transmits MBMS service data and is located between the base station 220 and the BM-SC, and performs MBMS packet transmission and broadcast to the base station 220. The MBMS gateway 270 uses PDCP and IP multicast to transmit user data to the base station 220, and performs session control signaling for the radio access network 200.

The interface between the MME 260 and the MCE 210 is a control plane interface between the radio access network 200 and the EPC 250, which is called an M3 interface, and transmits control information related to MBMS session control. The MME 260 and the MCE 210 transmit session control signaling, such as a session start / stop message for session start or session stop, to the base station 220, The base station 220 may inform the terminal that the MBMS service is started or stopped through cell notification.

The interface between the base station 220 and the MBMS gateway 270 is an interface of a user plane, which is called an M1 interface, and transmits MBMS service data.

3 shows an air interface protocol of an LTE system for a control plane and a user plane. 3 (a) is the air interface protocol of the LTE system for the control plane, and FIG. 3 (b) is the air interface protocol of the LTE system for the user plane.

The layer of the air interface protocol between the UE and the E-UTRAN is based on the lower three layers of the open system interconnection (OSI) model, which is well known in communication systems, and includes L1 (first layer), L2 (second layer), and L3 (third layer). Hierarchical). The air interface protocol between the UE and the E-UTRAN may be horizontally divided into a physical layer, a data link layer, and a network layer, and vertically a protocol stack for transmitting control signals. ) Can be divided into a control plane and a user plane which is a protocol stack for transmitting data information. Layers of the radio interface protocol may exist in pairs in the UE and the E-UTRAN, which may be responsible for data transmission of the Uu interface.

The physical layer (PHY) belongs to L1. The physical layer provides an information transmission service to a higher layer through a physical channel. The physical layer is connected to a higher layer of a media access control (MAC) layer through a transport channel. Physical channels are mapped to transport channels. Data may be transmitted between the MAC layer and the physical layer through a transport channel. Data between different physical layers, that is, between the physical layer of the transmitter and the physical layer of the receiver may be transmitted using radio resources through a physical channel. The physical layer may be modulated using an orthogonal frequency division multiplexing (OFDM) scheme, and utilizes time and frequency as radio resources.

The physical layer uses several physical control channels. A physical downlink control channel (PDCCH) reports resource allocation of a paging channel (PCH) and a downlink shared channel (DL-SCH), and hybrid automatic repeat request (HARQ) information related to the DL-SCH to the UE. The PDCCH may carry an uplink grant to report to the UE regarding resource allocation of uplink transmission. The physical control format indicator channel (PCFICH) informs the UE of the number of OFDM symbols used for the PDCCH and is transmitted every subframe. A physical hybrid ARQ indicator channel (PHICH) carries a HARQ ACK (non-acknowledgement) / NACK (non-acknowledgement) signal for UL-SCH transmission. A physical uplink control channel (PUCCH) carries UL control information such as HARQ ACK / NACK, a scheduling request, and a CQI for downlink transmission. The physical uplink shared channel (PUSCH) carries an uplink shared channel (UL-SCH).

The physical channel includes a plurality of subframes in the time domain and a plurality of subcarriers in the frequency domain. One subframe consists of a plurality of symbols in the time domain. One subframe consists of a plurality of resource blocks (RBs). One resource block is composed of a plurality of symbols and a plurality of subcarriers. In addition, each subframe may use specific subcarriers of specific symbols of the corresponding subframe for the PDCCH. For example, the first symbol of the subframe may be used for the PDCCH. The PDCCH may carry dynamically allocated resources, such as a physical resource block (PRB) and modulation and coding schemes (MCS). A transmission time interval (TTI), which is a unit time at which data is transmitted, may be equal to the length of one subframe. One subframe may have a length of 1 ms.

The transport channel is classified into a common transport channel and a dedicated transport channel depending on whether the channel is shared or not. A DL transport channel for transmitting data from a network to a UE includes a broadcast channel (BCH) for transmitting system information, a paging channel (PCH) for transmitting a paging message, and a DL-SCH for transmitting user traffic or control signals. And the like. The DL-SCH supports dynamic link adaptation and dynamic / semi-static resource allocation by varying HARQ, modulation, coding and transmit power. In addition, the DL-SCH may enable the use of broadcast and beamforming throughout the cell. System information carries one or more system information blocks. All system information blocks can be transmitted in the same period. Traffic or control signals of a multimedia broadcast / multicast service (MBMS) are transmitted through a multicast channel (MCH).

The UL transport channel for transmitting data from the terminal to the network includes a random access channel (RAC) for transmitting an initial control message, a UL-SCH for transmitting user traffic or a control signal, and the like. The UL-SCH can support dynamic link adaptation due to HARQ and transmit power and potential changes in modulation and coding. In addition, the UL-SCH may enable the use of beamforming. RACH is generally used for initial connection to a cell.

The MAC layer belonging to L2 provides a service to a radio link control (RLC) layer, which is a higher layer, through a logical channel. The MAC layer provides a mapping function from a plurality of logical channels to a plurality of transport channels. The MAC layer also provides a logical channel multiplexing function by mapping from multiple logical channels to a single transport channel. The MAC sublayer provides data transfer services on logical channels.

The logical channel may be divided into a control channel for information transmission in the control plane and a traffic channel for information transmission in the user plane according to the type of information to be transmitted. That is, a set of logical channel types is defined for other data transfer services provided by the MAC layer. The logical channel is located above the transport channel and mapped to the transport channel.

The control channel is used only for conveying information in the control plane. The control channel provided by the MAC layer includes a broadcast control channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH), and a dedicated control channel (DCCH). BCCH is a downlink channel for broadcasting system control information. PCCH is a downlink channel used for transmitting paging information and paging a terminal whose cell-level location is not known to the network. CCCH is used by the terminal when there is no RRC connection with the network. MCCH is a one-to-many downlink channel used to transmit MBMS control information from the network to the terminal. DCCH is a one-to-one bidirectional channel used by the terminal for transmitting dedicated control information between the terminal and the network in an RRC connection state.

The traffic channel is used only for conveying information in the user plane. The traffic channel provided by the MAC layer includes a dedicated traffic channel (DTCH) and a multicast traffic channel (MTCH). DTCH is used for transmission of user information of one UE in a one-to-one channel and may exist in both uplink and downlink. MTCH is a one-to-many downlink channel for transmitting traffic data from the network to the terminal.

The uplink connection between the logical channel and the transport channel includes a DCCH that can be mapped to the UL-SCH, a DTCH that can be mapped to the UL-SCH, and a CCCH that can be mapped to the UL-SCH. The downlink connection between the logical channel and the transport channel is a BCCH that can be mapped to a BCH or DL-SCH, a PCCH that can be mapped to a PCH, a DCCH that can be mapped to a DL-SCH, a DTCH that can be mapped to a DL-SCH, MCCH that can be mapped to MCH and MTCH that can be mapped to MCH.

The RLC layer belongs to L2. The function of the RLC layer includes adjusting the size of the data by segmentation / concatenation of the data received from the upper layer in the radio section such that the lower layer is suitable for transmitting data. In order to guarantee the various QoS required by the radio bearer (RB), the RLC layer is divided into three modes: transparent mode (TM), unacknowledged mode (UM) and acknowledged mode (AM). Provides three modes of operation. AM RLC provides retransmission through automatic repeat request (ARQ) for reliable data transmission. Meanwhile, the function of the RLC layer may be implemented as a functional block inside the MAC layer, in which case the RLC layer may not exist.

The packet data convergence protocol (PDCP) layer belongs to L2. The PDCP layer introduces an IP packet, such as IPv4 or IPv6, over a relatively low bandwidth air interface to provide header compression that reduces unnecessary control information so that the transmitted data is transmitted efficiently. Header compression improves transmission efficiency in the wireless section by transmitting only the information necessary for the header of the data. In addition, the PDCP layer provides security. Security functions include encryption to prevent third party inspection and integrity protection to prevent third party data manipulation.

The radio resource control (RRC) layer belongs to L3. The RRC layer at the bottom of L3 is defined only in the control plane. The RRC layer serves to control radio resources between the terminal and the network. To this end, the UE and the network exchange RRC messages through the RRC layer. The RRC layer is responsible for the control of logical channels, transport channels and physical channels in connection with the configuration, re-configuration and release of RBs. RB is a logical path provided by L1 and L2 for data transmission between the terminal and the network. That is, RB means a service provided by L2 for data transmission between the UE and the E-UTRAN. Setting up an RB means defining the characteristics of the radio protocol layer and channel to provide a particular service, and determining each specific parameter and method of operation. RBs may be classified into two types: signaling RBs (SRBs) and data RBs (DRBs). The SRB is used as a path for transmitting RRC messages in the control plane, and the 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.

Referring to FIG. 3 (a), the RLC and MAC layer (end at eNB in network side) may perform functions such as scheduling, ARQ and HARQ. The RRC layer (ended at the eNB at the network side) may perform functions such as broadcast, paging, RRC connection management, RB control, mobility function, and UE measurement report / control. The NAS control protocol (terminated at the gateway's MME at the network side) may perform functions such as SAE bearer management, authentication, LTE_IDLE mobility handling, paging initiation at LTE_IDLE, and security control for signaling between the terminal and the gateway.

Referring to FIG. 3 (b), the RLC and MAC layer (end at the eNB at the network side) may perform the same function as the function in the control plane. The PDCP layer (terminating at the eNB at the network side) may perform user plane functions such as header compression, integrity protection and encryption.

Hereinafter, the MBMS and MBSFN (multicast / broadcast single frequency network) will be described.

Transmission in MBSFN transmission or MBSFN mode refers to a simultaneous transmission scheme implemented by transmitting the same signal in a plurality of cells at the same time. MBSFN transmissions from a plurality of cells within the MBSFN area appear to the UE as a single transmission.

MBMS services can be managed or localized on a cell-based or geography-based basis. The MBMS service area is a general term for the area where a particular MBMS service is provided. For example, if an area where a specific MBMS service A is performed is called an MBMS service area A, the network may be in a state of transmitting an MBMS service A in the MBMS service area A. In this case, the terminal may receive the MBMS service A according to the capability of the terminal. The MBMS service area may be defined in terms of applications and services as to whether or not a particular service is provided in a certain area.

A logical channel multicast control channel (MCCH) or a multicast traffic channel (MTCH) may be mapped to a transport channel MCH for an MBMS. MCCH transmits MBMS related RRC message, and MTCH transmits traffic of specific MBMS service. There is one MCCH for each MBMS Single Frequency Network (MBSFN) region that transmits the same MBMS information / traffic. When a plurality of MBSFN regions are provided in one cell, the terminal may receive a plurality of MCCHs. The MCCH contains one MBSFN area setup RRC message and has a list of all MBMS services. When an MBMS-related RRC message is changed in a specific MCCH, a physical downlink control channel (PDCCH) transmits an MBMS Radio Network Temporary Identity (M-RNTI) and an indicator indicating a specific MCCH. The terminal supporting the MBMS may receive the M-RNTI and the MCCH indicator through the PDCCH, determine that the MBMS-related RRC message has been changed in the specific MCCH, and receive the specific MCCH. The RRC message of the MCCH may be changed at each modification period, and is repeatedly broadcasted at every repetition period. A notification mechanism is used to inform the change of the MCCH due to the presence of the MCCH session start or MBMS counting request message. The UE detects a known MCCH change through the MCCH monitoring in the change cycle, not by the notification mechanism. The MTCH is a logical channel carrying an MBMS service. When there are many services provided in the MBSFN area, a plurality of MTCHs may be configured.

The terminal may receive a dedicated service while receiving the MBMS service. For example, a user may watch a TV through an MBMS service through his own smartphone, and chat using an IM (instant messaging) service such as MSN or Skype using the smartphone. . In this case, the MBMS service is provided through MTCH received by several terminals together, and the service provided to each terminal individually, such as IM service, will be provided through a dedicated bearer such as DCCH or DTCH.

In one area, some base stations can use multiple frequencies at the same time. In this case, in order to efficiently use radio resources, the network may select one of a plurality of frequencies to provide an MBMS service only at that frequency and provide a dedicated bearer to each terminal at all frequencies. In this case, when a terminal that has received a service using a dedicated bearer at a frequency where the MBMS service is not provided, if the terminal wants to receive the MBMS service, the terminal should be handed over to a frequency where the MBMS service is provided. To this end, the terminal transmits an MBMS interest indication to the base station. That is, when the terminal wants to receive the MBMS service, the terminal transmits an MBMS interest indication to the base station. When the base station receives the instruction, the terminal recognizes that the terminal wants to receive the MBMS service, and the terminal receives the MBMS service frequency. Move to. The MBMS interest indicator refers to information that the terminal wants to receive the MBMS service, and additionally includes information on which frequency it wants to move to.

A terminal that wants to receive a specific MBMS service first grasps frequency information and broadcast time information provided with the specific service. If the MBMS service is already broadcasting or soon starts broadcasting, the terminal sets the highest priority of the frequency in which the MBMS service is provided. The UE moves to a cell providing the MBMS service and receives the MBMS service by performing a cell reselection procedure using the reset frequency priority information.

If the UE is receiving or is interested in receiving MBMS service and can receive the MBMS service while camped on the frequency at which the MBMS service is provided, the reselected cell is SIB13 (System Information Block 13; System Information). In the case of broadcasting block 13), it may be considered that the highest priority was applied to the corresponding frequency during the MBMS session as long as the following situation persists.

When indicated by SIB15 of the serving cell that one or more MBMS Service Area Identities (SAIs) are included in the User Service Description (USD) of the service.

SIB15 is not broadcasted in the serving cell and its frequency is included in the USD of the service.

The UE should be able to receive MBMS in RRC_IDLE and RRC_CONNECTED states.

4 shows an example in which system information and MBMS interest indication message for an MBMS service are transmitted.

Referring to FIG. 4, the base station transmits a system information block (SIB) 15 to the terminal. SIB15 is system information defined for MBMS service. SIB15 may include MBMS service area identifiers (SAIs) of current and / or neighboring carrier frequencies. Table 1 shows an example of SIB15.

-ASN1STARTSystemInformationBlockType15-r11 :: = SEQUENCE {sai-IntraFreq-r11 MBMS-SAI-List-r11 OPTIONAL,-Need ORsai-InterFreqList-r11 MBMS-SAI-InterFreqList-r11 OPTIONAL,-Need ORlateNonCriticalExtension OCTET STRING OPTIONAL -Need OP ...} MBMS-SAI-List-r11 :: = SEQUENCE (SIZE (1..maxSAI-MBMS-r11)) OF MBMS-SAI-r11MBMS-SAI-r11 :: = INTEGER (0..65535 MBMS-SAI-InterFreqList-r11 :: = SEQUENCE (SIZE (1..maxFreq)) OF MBMS-SAI-InterFreq-r11MBMS-SAI-InterFreq-r11 :: = SEQUENCE (dl-CarrierFreq ARFCN-ValueEUTRA, sai-List -r11 MBMS-SAI-List-r11, ...}-ASN1STOP

In Table 1, the sai-IntraFreq field includes a list of MBMS service area identifiers of carrier frequencies to which the UE is currently connected. The sai-InterFreqList field includes a list of neighbor frequencies for providing an MBMS service and a list of MBMS service region identifiers corresponding thereto. The sai-List field contains a list of MBMS service area identifiers for a specific frequency.

The terminal in the RRC connected state transmits an MBMS interest indication message to the base station through an MRB (MBMS point to multipoint radio bearer). The terminal may inform the base station through the MBMS interest indication message of a frequency for receiving or interested in receiving the MBMS service. The terminal may inform the base station through the MBMS interest indication message a frequency for providing the MBMS service that is no longer received or no longer interested in receiving. In addition, the UE may inform whether or not to prioritize reception of the MBMS service over unicast reception through an MBMS interest indication message. The MBMS interest indication message may be transmitted through a dedicated control channel (DCCH), which is a logical channel. The signaling radio bearer (SRB) for the MBMS interest indication message is SRB1, and the MBMS interest indication message may be transmitted based on the confirmation mode. Table 2 shows an example of an MBMS attention indication message.

-ASN1STARTMBMSInterestIndication-r11 :: = SEQUENCE {criticalExtensions CHOICE {c1 CHOICE {interestIndication-r11 MBMSInterestIndication-r11-IEs, spare3 NULL, spare2 NULL, spare1 NULL}, criticalExtensionsFuture SEQUENCE {}}} MBMSInterestIndication-r11UENCE-IEs {mbms-FreqList-r11 CarrierFreqListMBMS-r11 OPTIONAL, mbms-Priority-r11 ENUMERATED {true} OPTIONAL, lateNonCriticalExtension OCTET STRING OPTIONAL, nonCriticalExtension SEQUENCE {} OPTIONAL}-ASN1STOP

In Table 2, the mbms-FreqList field indicates a list of frequencies that the terminal is receiving or provides with MBMS service of interest. The mbms-Priority field indicates whether the UE has priority over MBMS reception over unicast reception. When the UE prioritizes reception of frequencies providing all MBMS services over reception of a unicast bearer, a value of the mbms-Priority field may be true. Otherwise, the mbms-Priority field may be omitted.

The base station receiving the MBMS interest indication message may know that the terminal is interested in moving to a cell operating at a frequency for providing an MBMS service. The base station may hand over the terminal to a cell of a specific frequency that provides a specific MBMS service, and may allow the terminal to receive the MBMS service smoothly after the handover. In addition, when the terminal handovers from the first base station to the second base station, the first base station may transmit the MBMS interest indication message received from the terminal to the second base station through the MBMS UE context (context). That is, the terminal does not need to retransmit the MBMS interest indication message to the second base station. Even after the terminal has handed over to the second base station, the second base station may allow the terminal to smoothly receive the MBMS service.

Hereinafter, single-cell point-to-multipoint transmission will be described.

The transmission method of MBMS service is SCPTM transmission and MBSFN (Multimedia Broadcast multicast service Single Frequency Network) transmission. While MBSFN transmissions transmit identifiable signals in multiple cells simultaneously, SCPTM transmissions carry MBMS services in a single cell. Thus, SCPTM transmissions do not require cell-to-cell synchronization unlike MBSFN transmissions. Also, since SCPTM transmission uses the existing PDSCH, it has unicast characteristics unlike MBSFN transmission. That is, a plurality of terminals read the same PDCCH, obtains an RNTI for each service and receives the SCPTM service. When the SCPTM dedicated MCCH is introduced and the terminal determines that the service I want is an SCPTM service through the MCCH, the terminal may receive the SCPTM service by acquiring the corresponding RNTI value and reading the PDCCH through the RNTI.

Hereinafter, the Internet of Things (IoT) will be described.

5 shows an example of IoT communication.

The IoT refers to the exchange of information through the base station 520 or the exchange of information through the base station between the IoT terminal 510 and the MTC server 530 between IoT terminals 510 that do not involve human interaction. The services provided through the IoT are different from those in traditional human-involved communication, and there are various categories of services such as tracking, metering, payment, medical services, and remote control. exist. More specifically, services provided through the IoT may include meter reading, water level measurement, the use of surveillance cameras, inventory reporting of vending machines, and the like. A low cost / low specification terminal focused on data communication for providing such a service may be referred to as an IoT terminal, an MTC terminal, or a low complexity type UE.

The IoT server 530 is an entity that communicates with the IoT terminal 510. The IoT server 530 executes an IoT application and provides an IoT specific service to an IoT terminal. The IoT terminal 510 is a wireless device that provides IoT communication and may be fixed or mobile.

In the case of IoT terminals, since the amount of data to be transmitted is small and uplink / downlink data transmission and reception occur occasionally, it is effective to lower the unit cost and reduce battery consumption in accordance with such a low data rate. The IoT terminal is characterized by low mobility, so the channel environment is hardly changed.

6 and 7 illustrate an example of a narrow band in which an IoT device operates.

As one method for low-cost of an IoT terminal, the IoT terminal may use a narrowband regardless of the system bandwidth of the cell. For example, the narrow band may have a bandwidth of about 1.4 MHz. In this case, as shown in FIG. 6, the narrow band region in which the IoT terminal operates may be located in the center region (eg, six PRBs) of the system bandwidth of the cell. Alternatively, as illustrated in FIG. 7, a plurality of narrowband regions in which the IoT terminals operate may exist in a plurality of subframes for multiplexing in subframes between the IoT terminals, and different IoT terminals may be different from each other. Bands can be used. In this case, most IoT terminals may use a narrow band other than the center region (eg, six PRBs) of the system band of the cell. As such, IoT communication operating on a reduced bandwidth may be referred to as NB (Narrow Band) IoT communication or NB CIoT communication.

Meanwhile, some terminals may not support handover as well as measurement report. For example, the terminal not supporting the handover as well as the measurement report may be an NB IoT terminal or a CIoT terminal. Therefore, even if a UE that does not support measurement report and handover transmits an MBMS interest indication message to the network, the network cannot handover the UE to a frequency that provides an MBMS service of interest. That is, the existing MBMS service continuity mechanism based on the MBMS interest indication message cannot provide the MBMS service continuity to terminals that do not support the measurement report or the handover. Hereinafter, a method and an apparatus supporting the MBMS service continuity for a terminal that does not support handover or measurement report according to an embodiment of the present invention will be described.

In case of an MBMS capable terminal that does not support handover or measurement reporting, the terminal may transmit an MBMS interest indication message to the network only when at least one of the following first to fifth conditions is satisfied. . For example, the MBMS capable terminal that does not support the handover or measurement report may be at least one of an NB-IoT terminal, a CIoT terminal, an IoT terminal, or an eMTC terminal.

1) First condition: The UE is in an RRC state that does not support UE based mobility. For example, terminal-based mobility may be cell reselection. For example, an RRC state that does not support terminal-based mobility may be an RRC_CONNECTED state. For example, an RRC state that does not support terminal-based mobility may be a newly defined RRC state.

2) Second condition: The terminal is interested in receiving MBMS service through broadcast. For example, the terminal is interested in receiving MBMS service through MBSFN transmission. For example, the terminal is interested in receiving MBMS service through SCPTM transmission.

3) Third condition: The terminal cannot receive the MBMS service through a broadcast from a serving frequency.

4) Fourth condition: The terminal can receive the MBMS service through broadcasting from a neighboring frequency.

5) Fifth condition: One MBMS session that the UE is receiving or interested in receiving through the MRB or SC-MRB is in progress or is about to start.

Alternatively, for an MBMS capable terminal that does not support handover or measurement reporting, if the terminal can receive the MBMS service through broadcast from a serving frequency, even if the transmission of the MBMS interest indication message is triggered, the terminal may receive MBMS interest. The indication message may not be sent to the network.

FIG. 8 illustrates a procedure in which a terminal supports MBMS service continuity based on an MBMS interest indication message according to an embodiment of the present invention.

Referring to FIG. 8, in step S810, the terminal may enter an RRC state that does not support terminal-based mobility. For example, an RRC state that does not support terminal-based mobility may be an RRC_CONNECTED state. For example, an RRC state that does not support terminal-based mobility may be a newly defined RRC state.

In step S820, the terminal may determine whether the MBMS service of interest can be received from the serving frequency. If it is determined that the MBMS service of interest is unreceivable from the serving frequency, in step S830, the terminal may transmit an MBMS interest indication message to the network. That is, a terminal interested in receiving an MBMS service first determines whether the MBMS service of interest can be received through a serving frequency, and then only when the MBMS service of interest cannot be received through a serving frequency. The MBMS attention indication message may be sent to the network. The MBMS interest indication may inform the network that the UE wants to enter the RRC_IDLE mode to change the serving frequency through a cell reselection procedure. In addition, the MBMS interest indication message may further include additional information. The additional information may indicate that the UE wants to enter the RRC_IDLE mode to change the serving frequency through a cell reselection procedure. If it is determined that the MBMS service of interest is receivable from the serving frequency, in step S830, the terminal may not transmit the MBMS interest indication message to the network. In other words, step S830 may be omitted.

In operation S840, the network may transmit an RRC connection release message to the terminal in response to the MBMS interest indication message. Alternatively, the network may transmit an RRC connection release message to the terminal in response to the MBMS interest indication message including the additional information.

In step S850, the UE that has received the RRC connection release message may enter the RRC_IDLE state and perform a cell reselection procedure.

Specifically, when the terminal receives an RRC connection release message having the cause of releasing 'MBMS service continuity' from the network, the terminal may prioritize the MBMS frequency provided with the MBMS service of interest. The terminal may perform a cell reselection procedure. As a result, the terminal may camp on to the cell providing the MBMS service of interest.

Preferably, after the UE camps on a cell providing the MBMS service of interest, the UE may initiate an RRC connection establishment procedure to recover unicast communication.

For example, the transmission of the MBMS interest indication message to the IoT terminal may be initiated by the procedure defined in Table 3. That is, if SIB15 is broadcast by the PCell and the terminal cannot receive the MBMS service of interest through the SCTPM transmission or the MBSFN transmission from the current serving frequency, the terminal may start transmitting the MBMS interest indication message.

An MBMS or SC-PTM capable UE in RRC_CONNECTED may initiate the procedure in several cases including upon successful connection establishment, upon entering or leaving the service area, upon session start or stop, upon change of interest, upon change of priority between MBMS reception and unicast reception or upon change to a PCell broadcasting SystemInformationBlockType15.Upon initiating the procedure, the IoT UE shall: 1> if SystemInformationBlockType15 is broadcast by the PCell and if the UE cannot receive the MBMS service of interest via MBSFN transmission or SCPTM transmission from current serving frequency; 2> ensure having a valid version of System Information BlockType 15 for the PCell; 2> if the UE did not transmit an MBMSInterestIndication message since last entering RRC_CONNECTED state; or 2> if since the last time the UE transmitted an MBMSInterestIndication message, the UE connected to a PCell not broadcasting System Information BlockType 15: 3> if the set of MBMS frequencies of interest is not empty: 4> initiate transmission of the MBMSInterestIndication message; 2> else: 3> if the set of MBMS frequencies of interest has changed since the last transmission of the MBMSInterestIndication message; or 3> if the prioritisation of reception of all indicated MBMS frequencies compared to reception of any of the established unicast bearers has changed since the last transmission of the MBMSInterestIndication message: 4> initiate transmission of the MBMSInterestIndication message; NOTE: The UE may send an MBMSInterestIndication even when it is able to receive the MBMS services it is interested in ie to avoid that the network allocates a configuration inhibiting MBMS reception. 3> else if SystemInformationBlockType20 is broadcast by the PCell: 4> if since the last time the UE transmitted an MBMSInterestIndication message, the UE connected to a PCell not broadcasting SystemInformationBlockType20; or 4> if the set of MBMS services of interest is different from mbms-Services included in the last transmission of the MBMSInterestIndication message; 5> initiate the transmission of the MBMSInterestIndication message.

According to an embodiment of the present invention, when a terminal that does not support handover is in an RRC state that does not support terminal-based mobility, if the terminal does not receive the MBMS service of interest from the serving frequency, the terminal indicates MBMS interest The RRC_IDLE state can be entered by sending a message to the network. Accordingly, the terminal may perform cell reselection at a neighbor frequency for providing the MBMS service of interest and receive the MBMS service of interest.

9 illustrates a procedure of performing cell reselection by a UE in an RRC_IDLE state according to an embodiment of the present invention.

Referring to FIG. 9, in step S910, the terminal may receive a system information block from a serving cell. The terminal may be a terminal in an RRC_IDLE state. And, the terminal may be a terminal interested in receiving the MBMS service. The terminal may be at least one of an NB-IoT terminal, a CIoT terminal, an IoT terminal, or an eMTC terminal. The eMTC terminal may be a terminal in enhanced coverage. The MBMS service may be received via SCPTM transmission or MBSFN transmission. The system information block may be SIB20.

In operation S920, the terminal that receives the system information block from the serving cell may identify the neighbor cell providing the MBMS service of interest based on the information included in the system information block. There may be a plurality of neighbor cells providing the MBMS service of interest.

In step S930, before performing cell reselection for all measured neighbor cells, the UE may determine whether to consider the neighbor cell as a target cell for cell reselection. If at least one of the first to third conditions is satisfied, the terminal may regard the neighbor cell as a target of cell reselection.

1) First condition: A neighbor cell provides an MBMS service of interest.

2) Second condition: The quality of the neighbor cell exceeds the threshold.

3) Third condition: The neighboring cell satisfies the cell selection criterion S. The cell selection criteria may be defined as in Equation 1.

Srxlev represents a cell selection RX level value (dB), and Squal represents a cell selection quality value (dB).

In a first condition, the MBMS service of interest may be provided via SCPTM transmission or MBSFN transmission. In a second condition, the quality of the neighbor cell may be at least one of RSRP or RSRQ of the neighbor cell. In a second condition, the threshold may be at least one of an RSRP threshold or an RSRQ threshold. The terminal may receive the threshold value from the network before step S930.

For example, before performing cell reselection for all measured neighboring cells, the UE is a target for cell reselection of only neighboring cells having a quality exceeding a threshold value among a plurality of neighboring cells providing the MBMS service of interest. Can be regarded as a cell.

For example, before performing cell reselection for all measured neighboring cells, the UE selects only neighboring cells satisfying the cell selection criterion S among the plurality of neighboring cells providing the MBMS service of interest as target cells for cell reselection. Can be considered.

For example, if there is no neighbor cell that satisfies the above conditions, the terminal may regard all neighbor cells as target cells for cell reselection.

In step S940, the terminal may perform a cell reselection procedure for the restricted target cell. That is, the terminal does not perform a cell reselection procedure for all neighbor cells providing the MBMS service of interest and satisfies at least one of the second condition or the third condition among all neighbor cells providing the MBMS service of interest. The cell reselection procedure may be performed only for neighboring cells. Thereafter, the terminal may reselect the serving cell through cell reselection among the restricted target cells.

If the MBMS service of interest is changed and the terminal cannot receive the MBMS service of interest through SCPTM transmission or MBSFN transmission from the reselected serving cell, the terminal may perform steps S910 to S940 again.

If the terminal is no longer interested in receiving the MBMS service, the terminal may perform a legacy cell reselection procedure. The legacy cell reselection procedure may be performed without limitation of the target cell.

According to an embodiment of the present invention, before performing cell reselection for all measured neighbor cells, the UE performs cell reselection of only neighboring cells satisfying a specific condition among a plurality of neighboring cells providing the MBMS service of interest. Can be regarded as a target cell.

10 is a block diagram illustrating a method of supporting an MBMS service continuity by a terminal according to an embodiment of the present invention.

Referring to FIG. 10, in step S1010, the UE may enter an RRC state that does not support cell reselection. The terminal may be a terminal that does not support handover. The terminal may be at least one of an NB-IoT terminal, a CIoT terminal, an IoT terminal, or an eMTC terminal.

In step S1020, the terminal may determine whether the MBMS service of interest can be received from the serving frequency of the terminal.

In step S1030, if it is determined that the MBMS service of interest cannot be received from the serving frequency, the terminal may transmit an MBMS interest indication message to the network. The network may be a radio access technology (RAT) that does not support handover.

Additionally, the terminal may receive an RRC connection release message from the network in response to the transmitted MBMS interest indication message. Additionally, the terminal may enter the RRC_IDLE state in response to the received RRC connection release message. Additionally, the terminal may perform cell reselection to a neighbor cell providing the MBMS service of interest. Additionally, the terminal may receive the MBMS service of interest from the reselected neighbor cell. The MBMS service of interest may be received via MBSFN transmission or SCPTM transmission.

After the UE enters the RRC_IDLE state, the UE may additionally receive a system information block from the serving frequency and determine a neighbor cell providing the MBMS service of interest based on the system information block.

Additionally, the UE may regard at least one cell having a cell quality exceeding a threshold value among neighboring cells providing the MBMS service of interest as a target cell for cell reselection. The threshold may be received from the serving frequency. The cell quality may be at least one of RSRP or RSRQ. In addition, the terminal may perform a cell reselection procedure for at least one target cell considered.

In addition, the UE may regard at least one cell satisfying a cell selection criterion S (S) among neighboring cells providing the MBMS service of interest as a target cell for cell reselection.

11 is a block diagram of a wireless communication system in which an embodiment of the present invention is implemented.

The base station 1100 includes a processor 1101, a memory 1102, and a transceiver 1103. The memory 1102 is connected to the processor 1101 and stores various information for driving the processor 1101. The transceiver 1103 is connected to the processor 1101 and transmits and / or receives a radio signal. The processor 1101 implements the proposed functions, processes and / or methods. In the above-described embodiment, the operation of the base station may be implemented by the processor 1101.

The terminal 1110 includes a processor 1111, a memory 1112, and a transceiver 1113. The memory 1112 is connected to the processor 1111 and stores various information for driving the processor 1111. The transceiver 1113 is connected to the processor 1111 to transmit and / or receive a radio signal. Processor 1111 implements the proposed functions, processes, and / or methods. In the above-described embodiment, the operation of the terminal may be implemented by the processor 1111.

The processor may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, and / or data processing devices. The memory may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium and / or other storage device. The transceiver may include baseband circuitry for processing wireless signals. When the embodiment is implemented in software, the above technique may be implemented as a module (process, function, etc.) for performing the above-described function. The module may be stored in memory and executed by a processor. The memory may be internal or external to the processor and may be coupled to the processor by various well known means.

Based on the examples described above, various techniques in accordance with the present disclosure have been described with reference to the drawings and reference numerals. For convenience of description, each technique described a number of steps or blocks in a specific order, but the specific order of these steps or blocks does not limit the invention described in the claims, and each step or block may be implemented in a different order, or In other words, it is possible to be performed simultaneously with other steps or blocks. In addition, it will be apparent to those skilled in the art that the steps or blocks have not been described in detail, and that at least one other step may be added or deleted without departing from the scope of the invention.

The above-described embodiments include various examples. Those skilled in the art will appreciate that not all possible combinations of examples of the inventions can be described, and that various combinations can be derived from the description herein. Therefore, the protection scope of the invention should be judged by combining various examples described in the detailed description within the scope of the claims described below.

Claims (15)

A method for supporting a multimedia broadcast multicast service (MBMS) service continuity in a wireless communication system by a terminal, Entering an RRC state that does not support cell reselection; Determining whether an MBMS service of interest (MBMS service) of interest can be received from a serving frequency of the terminal; And If it is determined that the MBMS service of interest cannot be received from the serving frequency, sending an MBMS interest indication message to the network; The terminal is a method characterized in that the terminal does not support handover (handover). The method of claim 1, Receiving an RRC connection release message from the network in response to the transmitted MBMS attention indication message. The method of claim 2, And entering an RRC_IDLE state in response to the received RRC connection release message. The method of claim 3, wherein And performing cell reselection to a neighbor cell providing the MBMS service of interest. The method of claim 4, wherein Receiving the MBMS service of interest from the reselected neighbor cell. The method of claim 5, wherein The MBMS service of interest is received via multimedia broadcast single frequency network (MBSFN) transmission or single cell point to multipoint (SCPM) transmission. The method of claim 3, wherein After entering the RRC_IDLE state, receiving a system information block from the serving frequency; And Determining a neighbor cell providing the MBMS service of interest based on the system information block. The method of claim 7, wherein Considering at least one cell having a cell quality exceeding a threshold value among neighboring cells providing the MBMS service of interest as a target cell for cell reselection. The method of claim 8, The threshold value is received from the serving frequency. The method of claim 8, Wherein the cell quality is at least one of a reference signal received power (RSRP) or a reference signal received quality (RSRQ). The method of claim 8, And performing a cell reselection procedure for the at least one target cell considered. The method of claim 7, wherein And considering at least one cell that satisfies a cell selection criterion (S) among neighboring cells providing the MBMS service of interest as a target cell for cell reselection. The method of claim 1, The network is a radio access technology (RAT) that does not support handover. The method of claim 1, The terminal is at least one of the NB-IoT terminal, CIoT terminal, IoT terminal or eMTC terminal. In a terminal supporting a multimedia broadcast multicast service (MBMS) service continuity in a wireless communication system, Memory; Transceiver; And a processor connecting the memory and the transceiver, wherein the processor Enter an RRC state that does not support cell reselection, Determine whether the MBMS service of interest can be received from the serving frequency of the terminal; If it is determined that the MBMS service of interest cannot be received from the serving frequency, the transceiver controls to send an MBMS interest indication message to the network. The terminal is a terminal characterized in that the terminal does not support handover (handover).

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