WO2016140538A1 - Method for transmitting and receiving mbms related signal in wireless communication system, and device therefor - Google Patents

Abstract

One embodiment of the present invention provides a method for transmitting and receiving a multimedia broadcast multicast services (MBMS) related signal of a multi-cell/multicast coordination entity (MCE) in a wireless communication system, the method comprising the steps of: receiving a session start message including service area identities (SAIs) and a first ECGI list; configuring an MBSFN list by using the SAIs; removing, from the MBSFN list, an MBSFN to which a resource is not required to be allocated, on the basis of the first ECGI list; allocating a resource for an MBMS bearer on the basis of the first ECGI list and the MBSFN list, from which the MBSFN, to which the resource is not required to be allocated, is removed; configuring a second ECGI list for which MBMS transmission is to be performed through the resource allocation; and transmitting the second ECGI list to a network, wherein the second ECGI list includes ECGI grouping information if the MCE cannot use a single cell point to multipoint (SC-PTM) transmission or determines to use an MBSFN transmission method even if the SC-PTM transmission is possible.

Description

Method for transmitting / receiving MBMS related signal in wireless communication system and apparatus therefor

The following description relates to a wireless communication system, and more particularly, to a method and apparatus for transmitting and receiving signals related to multimedia broadcast multicast services (MBMS) of a multi-cell / multicast coordination entity (MCE).

Wireless communication systems are widely deployed to provide various kinds of communication services such as voice and data. In general, a wireless communication system is a multiple access system capable of supporting communication with multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and single carrier frequency (SC-FDMA). division multiple access (MCD) systems and multi-carrier frequency division multiple access (MC-FDMA) systems.

In the present invention, it is a technical problem to solve an unnecessary occurrence of a transmission stop request for each cell.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

According to an embodiment of the present invention, a method for transmitting and receiving a signal related to MBMS (Multimedia Broadcast Multicast Services) of a multi-cell / multicast coordination entity (MCE) in a wireless communication system includes a service area identifier (SAI) and a first ECGI list. Receiving a session start message; Constructing an MBSFN list using the SAI; Removing from the MBSFN list an MBSFN that does not need to allocate resources based on the first ECGI list; Allocating a resource for an MBMS bearer based on the MBSFN list from which the MBSFN has not been allocated and the first ECGI list; Constructing a second ECGI list to which MBMS transmission is to be performed by the resource allocation; And transmitting the second ECGI list to the network, wherein the MCE is not capable of Single Cell Point To Multiploint (SC-PTM) or if SC-PTM is available but decides to use an MBSFN transmission scheme. In any case, the second ECGI list is an MBMS related signal transmission / reception method including ECGI grouping information.

An embodiment of the present invention, a multi-cell / Multicast Coordination Entity (MCE) device for transmitting and receiving MBMS (Multimedia Broadcast Multicast Services) related signals in a wireless communication system, the transceiver; And a processor, wherein the processor receives a session start message including a service area identifier (SAI) and a first ECGI list, constructs an MBSFN list using the SAI, and configures the first ECGI list. Remove the MBSFN from the MBSFN list that does not need to allocate resources based on the resource allocation, allocate the resource for the MBMS bearer based on the MBSFN list and the first ECGI list from which the MBSFN does not need to allocate the resource; Compose a second ECGI list to perform MBMS transmission through the resource allocation, transmit the second ECGI list to the network, when the MCE is not capable of Single Cell Point To Multiploint (SC-PTM) or SC- In any of the cases where PTM is possible but decided to use the MBSFN transmission scheme, the second ECGI list is an MCE device that includes ECGI grouping information.

When the SC-PTM is available, the MCE may determine whether to use the MBSFN transmission scheme in consideration of the relationship between the number of cells of the first ECGI list and the number of cells of the second ECGI list.

When the number of cells of the first ECGI list with respect to the number of cells of the second ECGI list is larger than a preset value, the MCE may decide to use the MBSFN transmission scheme although SC-PTM is possible.

A transmission stop request for some of the cells indicated in the ECGI grouping information may not be allowed.

For some of the cells indicated in the ECGI grouping information, the change of the transmission scheme from MBMS to unicast may not be allowed.

The second ECGI list may be delivered to a group communication service application server (GCS AS) through a mobility management entity (MME), an MBMS gateway, and a broadcast multicast service center (BM-SC).

According to the present invention, it is possible to reduce unnecessary signaling exchange, network resource waste, etc., which may occur when a cell stop request is transmitted.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings appended hereto are for the purpose of providing an understanding of the present invention and for illustrating various embodiments of the present invention and for describing the principles of the present invention together with the description of the specification.

1 is a diagram illustrating a schematic structure of an EPS (Evolved Packet System) including an Evolved Packet Core (EPC).

2 is an exemplary view showing the architecture of a general E-UTRAN and EPC.

3 is an exemplary view showing the structure of a radio interface protocol in a control plane.

4 is an exemplary view showing the structure of a radio interface protocol in a user plane.

5 is a flowchart illustrating a random access procedure.

6 is a diagram illustrating a connection process in a radio resource control (RRC) layer.

7 is an example of a non-roaming architecture model for Group Communication System Enablers for LTE (GCSE_LTE).

8 shows a media traffic delivery procedure of unicast and MBMS.

9 is an illustration of an Activate MBMS bearer procedure.

10 is an illustration of an MBMS bearer initialization procedure.

11 is an illustration of an MBMS bearer notification procedure.

12 is a logical structure of an MCE (Multi-cell / Multicast Coordination Entity).

13 is a diagram illustrating a cell-by-cell transmission stop request according to the prior art.

14 is a view for explaining the operation of the MCE according to an embodiment of the present invention.

15 is a diagram illustrating a configuration of a node device according to an embodiment of the present invention.

The following embodiments combine the components and features of the present invention in a predetermined form. Each component or feature may be considered to be optional unless otherwise stated. Each component or feature may be embodied in a form that is not combined with other components or features. In addition, some components and / or features may be combined to form an embodiment of the present invention. The order of the operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment.

Specific terms used in the following description are provided to help the understanding of the present invention, and the use of such specific terms may be changed to other forms without departing from the technical spirit of the present invention.

In some instances, well-known structures and devices may be omitted or shown in block diagram form centering on the core functions of the structures and devices in order to avoid obscuring the concepts of the present invention. In addition, the same components will be described with the same reference numerals throughout the present specification.

Embodiments of the present invention may be supported by standard documents disclosed in relation to at least one of the Institute of Electrical and Electronics Engineers (IEEE) 802 series system, 3GPP system, 3GPP LTE and LTE-A system, and 3GPP2 system. That is, steps or parts which are not described to clearly reveal the technical spirit of the present invention among the embodiments of the present invention may be supported by the above documents. In addition, all terms disclosed in the present document can be described by the above standard document.

The following techniques can be used in various wireless communication systems. For clarity, the following description focuses on 3GPP LTE and 3GPP LTE-A systems, but the technical spirit of the present invention is not limited thereto.

Terms used in this document are defined as follows.

UMTS (Universal Mobile Telecommunications System): A third generation mobile communication technology based on Global System for Mobile Communication (GSM) developed by 3GPP.

Evolved Packet System (EPS): A network system composed of an Evolved Packet Core (EPC), which is a packet switched (PS) core network based on Internet Protocol (IP), and an access network such as LTE / UTRAN. UMTS is an evolutionary network.

NodeB: base station of GERAN / UTRAN. It is installed outdoors and its coverage is macro cell size.

eNodeB: base station of E-UTRAN. It is installed outdoors and its coverage is macro cell size.

UE (User Equipment): a user device. The UE may be referred to in terms of terminal, mobile equipment (ME), mobile station (MS), and the like. In addition, the UE may be a portable device such as a laptop, a mobile phone, a personal digital assistant (PDA), a smart phone, a multimedia device, or the like, or may be a non-portable device such as a personal computer (PC) or a vehicle-mounted device. In the context of MTC, the term UE or UE may refer to an MTC device.

Home NodeB (HNB): A base station of a UMTS network, which is installed indoors and has a coverage of a micro cell.

HeNB (Home eNodeB): A base station of an EPS network, which is installed indoors and its coverage is micro cell size.

Mobility Management Entity (MME): A network node of an EPS network that performs mobility management (MM) and session management (SM) functions.

Packet Data Network-Gateway (PDN-GW) / PGW: A network node of an EPS network that performs UE IP address assignment, packet screening and filtering, charging data collection, and the like.

Serving Gateway (SGW): A network node of an EPS network that performs mobility anchor, packet routing, idle mode packet buffering, and triggers the MME to page the UE.

Non-Access Stratum (NAS): Upper stratum of the control plane between the UE and the MME. A functional layer for exchanging signaling and traffic messages between a UE and a core network in an LTE / UMTS protocol stack, which supports session mobility and establishes and maintains an IP connection between the UE and the PDN GW. Supporting is the main function.

Packet Data Network (PDN): A network in which a server supporting a specific service (eg, a Multimedia Messaging Service (MMS) server, a Wireless Application Protocol (WAP) server, etc.) is located.

PDN connection: A logical connection between the UE and the PDN, represented by one IP address (one IPv4 address and / or one IPv6 prefix).

RAN (Radio Access Network): a unit including a NodeB, an eNodeB and a Radio Network Controller (RNC) controlling them in a 3GPP network. It exists between UEs and provides a connection to the core network.

Home Location Register (HLR) / Home Subscriber Server (HSS): A database containing subscriber information in the 3GPP network. The HSS may perform functions such as configuration storage, identity management, and user state storage.

Public Land Mobile Network (PLMN): A network composed for the purpose of providing mobile communication services to individuals. It may be configured separately for each operator.

Proximity Service (or ProSe Service or Proximity based Service): A service that enables discovery and direct communication between physically close devices or communication through a base station or through a third party device. In this case, user plane data is exchanged through a direct data path without passing through a 3GPP core network (eg, EPC).

ProSe communication: Means communication through a ProSe communication path between two or more ProSe capable terminals. Unless specifically stated otherwise, ProSe communication may mean one of ProSe E-UTRA communication, ProSe-assisted WLAN direct communication between two terminals, ProSe group communication, or ProSe broadcast communication.

-ProSe E-UTRA communication: ProSe communication using ProSe E-UTRA communication path

ProSe-assisted WLAN direct communication: ProSe communication using a direct communication path

ProSe communication path: As a communication path supporting ProSe communication, a ProSe E-UTRA communication path may be established between ProSe-enabled UEs or through a local eNB using E-UTRA. ProSe-assisted WLAN direct communication path can be established directly between ProSe-enabled UEs using WLAN.

EPC path (or infrastructure data path): user plane communication path through EPC

ProSe Discovery: A process of identifying / verifying a nearby ProSe-enabled terminal using E-UTRA

ProSe Group Communication: One-to-many ProSe communication using a common communication path between two or more ProSe-enabled terminals in close proximity.

ProSe UE-to-Network Relay: ProSe-enabled public safety terminal acting as a communication relay between ProSe-enabled network using E-UTRA and ProSe-enabled public safety terminal

ProSe UE-to-UE Relay: A ProSe-enabled public safety terminal operating as a ProSe communication relay between two or more ProSe-enabled public safety terminals.

-Remote UE: In the UE-to-Network Relay operation, a ProSe-enabled public safety terminal that is connected to the EPC network through ProSe UE-to-Network Relay without receiving service by E-UTRAN, that is, provides a PDN connection, and is a UE. In -to-UE Relay operation, a ProSe-enabled public safety terminal that communicates with other ProSe-enabled public safety terminals through a ProSe UE-to-UE Relay.

ProSe-enabled Network: A network that supports ProSe Discovery, ProSe Communication, and / or ProSe-assisted WLAN direct communication. Hereinafter, the ProSe-enabled Network may be referred to simply as a network.

ProSe-enabled UE: a terminal supporting ProSe discovery, ProSe communication and / or ProSe-assisted WLAN direct communication. Hereinafter, the ProSe-enabled UE and the ProSe-enabled Public Safety UE may be called terminals.

Proximity: Satisfying proximity criteria defined in discovery and communication, respectively.

SULP Location Platform (SLP): An entity that manages Location Service Management and Position Determination. SLP includes a SPL (SUPL Location Center) function and a SPC (SUPL Positioning Center) function. For details, refer to the Open Mobile Alliance (OMA) standard document OMA AD SUPL: "Secure User Plane Location Architecture".

User Service Description (USD): The application / service layer includes Temporary Mobile Group Identity (TMGI) for each MBMS service, session start and end time, frequencies, MBMS service area identities (MBMS SAIs) information belonging to the MBMS service area. To put in USD to the terminal. See 3GPP TS 23.246 for details.

ISR (Idle mode Signaling Reduction): When a terminal frequently moves between E-UTRAN and UTRAN / GERAN, waste of network resources occurs by repeated location registration procedure. As a way to reduce this, when the terminal is in idle mode, two RATs (Radio Access Technology) already registered after the location registration with MME and SGSN (hereinafter referred to as mobility management node) via E-UTRAN and UTRAN / GERAN, respectively. This is a technology that does not register a separate location when moving between cells or performing cell reselection. Therefore, when DL (downlink) data arrives to the terminal, paging is simultaneously sent to the E-UTRAN and UTRAN / GERAN, thereby successfully finding the terminal and delivering the DL data. [See 3GPP TS 23.401 and 3GPP TS 23.060]

MBMS Single Frequency Network (MBSFN): A simulcast transmission technique implemented by simultaneously transmitting the same waveform to multiple grouped cells covering a certain area.

Evolved Packet Core (EPC)

1 is a diagram illustrating a schematic structure of an EPS (Evolved Packet System) including an Evolved Packet Core (EPC).

EPC is a key element of System Architecture Evolution (SAE) to improve the performance of 3GPP technologies. SAE is a research project to determine network structure supporting mobility between various kinds of networks. SAE aims to provide an optimized packet-based system, for example, supporting various radio access technologies on an IP basis and providing enhanced data transfer capabilities.

Specifically, the EPC is a core network of an IP mobile communication system for a 3GPP LTE system and may support packet-based real-time and non-real-time services. In a conventional mobile communication system (i.e., a second generation or third generation mobile communication system), the core network is divided into two distinct sub-domains of circuit-switched (CS) for voice and packet-switched (PS) for data. The function has been implemented. However, in the 3GPP LTE system, an evolution of the third generation mobile communication system, the sub-domains of CS and PS have been unified into one IP domain. That is, in the 3GPP LTE system, the connection between the terminal and the terminal having the IP capability (capability), IP-based base station (for example, eNodeB (evolved Node B)), EPC, application domain (for example, IMS ( IP Multimedia Subsystem)). That is, EPC is an essential structure for implementing end-to-end IP service.

The EPC may include various components, and in FIG. 1, some of them correspond to a serving gateway (SGW), a packet data network gateway (PDN GW), a mobility management entity (MME), and a serving general packet (SGRS) Radio Service (Supporting Node) and Enhanced Packet Data Gateway (ePDG) are shown.

The SGW (or S-GW) acts as a boundary point between the radio access network (RAN) and the core network, and is an element that functions to maintain a data path between the eNodeB and the PDN GW. In addition, when the UE moves over the area served by the eNodeB, the SGW serves as a local mobility anchor point. That is, packets may be routed through the SGW for mobility in the E-UTRAN (Universal Mobile Telecommunications System (Evolved-UMTS) Terrestrial Radio Access Network defined in 3GPP Release-8 or later). SGW also provides mobility with other 3GPP networks (RANs defined before 3GPP Release-8, such as UTRAN or GERAN (Global System for Mobile Communication (GSM) / Enhanced Data rates for Global Evolution (EDGE) Radio Access Network). It can also function as an anchor point.

The PDN GW (or P-GW) corresponds to the termination point of the data interface towards the packet data network. The PDN GW may support policy enforcement features, packet filtering, charging support, and the like. In addition, mobility management between 3GPP networks and non-3GPP networks (for example, untrusted networks such as Interworking Wireless Local Area Networks (I-WLANs), code-division multiple access (CDMA) networks, or trusted networks such as WiMax) Can serve as an anchor point for.

Although the example of the network structure of FIG. 1 shows that the SGW and the PDN GW are configured as separate gateways, two gateways may be implemented according to a single gateway configuration option.

The MME is an element that performs signaling and control functions to support access to the network connection of the UE, allocation of network resources, tracking, paging, roaming and handover, and the like. The MME controls control plane functions related to subscriber and session management. The MME manages a number of eNodeBs and performs signaling for the selection of a conventional gateway for handover to other 2G / 3G networks. The MME also performs functions such as security procedures, terminal-to-network session handling, and idle terminal location management.

SGSN handles all packet data, such as user's mobility management and authentication to other 3GPP networks (eg GPRS networks).

The ePDG acts as a secure node for untrusted non-3GPP networks (eg, I-WLAN, WiFi hotspots, etc.).

As described with reference to FIG. 1, a terminal having IP capability is an IP service network provided by an operator (ie, an operator) via various elements in the EPC, based on 3GPP access as well as non-3GPP access. (Eg, IMS).

1 illustrates various reference points (eg, S1-U, S1-MME, etc.). In the 3GPP system, a conceptual link defining two functions existing in different functional entities of E-UTRAN and EPC is defined as a reference point. Table 1 below summarizes the reference points shown in FIG. 1. In addition to the examples of Table 1, there may be various reference points according to the network structure.

Table 1

Reference point	Explanation
S1-MME	Reference point for the control plane protocol between E-UTRAN and MME
S1-U	Reference point between E-UTRAN and Serving GW for the per bearer user plane tunneling and inter eNodeB path switching during handover
S3	Reference point between the MME and SGSN providing user and bearer information exchange for mobility between 3GPP access networks in idle and / or active state. This reference point can be used in PLMN-to-PLMN-to-for example (for PLMN-to-PLMN handovers) (It enables user and bearer information exchange for inter 3GPP access network mobility in idle and / or active state This reference point can be used intra-PLMN or inter-PLMN (eg in the case of Inter-PLMN HO).)
S4	(Reference point between SGW and SGSN that provides related control and mobility support between the GPRS core and SGW's 3GPP anchor functionality.It also provides user plane tunneling if no direct tunnel is established.) and the 3GPP Anchor function of Serving GW.In addition, if Direct Tunnel is not established, it provides the user plane tunnelling.)
S5	Reference point providing user plane tunneling and tunnel management between the SGW and the PDN GW. It provides user plane tunneling and tunnel management between Serving GW and PDN GW. for Serving GW relocation due to UE mobility and if the Serving GW needs to connect to a non-collocated PDN GW for the required PDN connectivity.)
S11	Reference point between MME and SGW
SGi	Reference point between the PDN GW and the PDN. The PDN may be an operator external public or private PDN or, for example, an in-operator PDN for the provision of IMS services. It is the reference point between the PDN GW and the packet data network.Packet data network may be an operator external public or private packet data network or an intra operator packet data network, eg for provision of IMS services.This reference point corresponds to Gi for 3GPP accesses.)

Among the reference points shown in FIG. 1, S2a and S2b correspond to non-3GPP interfaces. S2a is a reference point that provides the user plane with associated control and mobility support between trusted non-3GPP access and PDN GW. S2b is a reference point that provides the user plane with relevant control and mobility support between the ePDG and PDN GW.

2 is an exemplary view showing the architecture of a general E-UTRAN and EPC.

As shown, an eNodeB can route to a gateway, schedule and send paging messages, schedule and send broadcaster channels (BCHs), and resources in uplink and downlink while an RRC (Radio Resource Control) connection is active. Can perform functions for dynamic allocation to the UE, configuration and provision for measurement of the eNodeB, radio bearer control, radio admission control, and connection mobility control. Within the EPC, paging can occur, LTE_IDLE state management, user plane can perform encryption, SAE bearer control, NAS signaling encryption and integrity protection.

3 is an exemplary diagram illustrating a structure of a radio interface protocol in a control plane between a terminal and a base station, and FIG. 4 is an exemplary diagram illustrating a structure of a radio interface protocol in a user plane between a terminal and a base station. .

The air interface protocol is based on the 3GPP radio access network standard. The air interface protocol is composed of a physical layer, a data link layer, and a network layer horizontally, and a user plane and control for data information transmission vertically. It is divided into a control plane for signal transmission.

The protocol layers are based on the lower three layers of the Open System Interconnection (OSI) reference model, which is widely known in communication systems, and includes L1 (first layer), L2 (second layer), and L3 (third layer). ) Can be separated.

Hereinafter, each layer of the radio protocol of the control plane shown in FIG. 3 and the radio protocol in the user plane shown in FIG. 4 will be described.

The physical layer, which is the first layer, provides an information transfer service using a physical channel. The physical layer is connected to a medium access control layer on the upper side through a transport channel, and data between the medium access control layer and the physical layer is transmitted through the transport channel. In addition, data is transferred between different physical layers, that is, between physical layers of a transmitting side and a receiving side through a physical channel.

The physical channel is composed of several subframes on the time axis and several sub-carriers on the frequency axis. Here, one subframe includes a plurality of symbols and a plurality of subcarriers on the time axis. One subframe consists of a plurality of resource blocks, and one resource block consists of a plurality of symbols and a plurality of subcarriers. The transmission time interval (TTI), which is a unit time for transmitting data, is 1 ms corresponding to one subframe.

According to 3GPP LTE, the physical channels existing in the physical layer of the transmitting side and the receiving side are physical downlink shared channel (PDSCH), physical uplink shared channel (PUSCH) and physical downlink control channel (PDCCH), which are control channels, It may be divided into a Physical Control Format Indicator Channel (PCFICH), a Physical Hybrid-ARQ Indicator Channel (PHICH), and a Physical Uplink Control Channel (PUCCH).

There are several layers in the second layer.

First, the medium access control (MAC) layer of the second layer serves to map various logical channels to various transport channels, and also logical channel multiplexing to map several logical channels to one transport channel. (Multiplexing). The MAC layer is connected to the upper layer RLC layer by a logical channel, and the logical channel includes a control channel for transmitting information of a control plane according to the type of information to be transmitted. It is divided into a traffic channel that transmits user plane information.

The Radio Link Control (RLC) layer of the second layer adjusts the data size so that the lower layer is suitable for transmitting data to the radio section by segmenting and concatenating data received from the upper layer. It plays a role.

The Packet Data Convergence Protocol (PDCP) layer of the second layer is an IP containing relatively large and unnecessary control information for efficient transmission in a wireless bandwidth where bandwidth is small when transmitting an IP packet such as IPv4 or IPv6. Performs Header Compression which reduces the packet header size. In addition, in the LTE system, the PDCP layer also performs a security function, which is composed of encryption (Ciphering) to prevent third-party data interception and integrity protection (Integrity protection) to prevent third-party data manipulation.

The radio resource control layer (hereinafter RRC) layer located at the top of the third layer is defined only in the control plane, and the configuration and resetting of radio bearers (abbreviated as RBs) are performed. It is responsible for the control of logical channels, transport channels and physical channels in relation to configuration and release. In this case, RB means a service provided by the second layer for data transmission between the terminal and the E-UTRAN.

If there is an RRC connection (RRC connection) between the RRC of the terminal and the RRC layer of the wireless network, the terminal is in the RRC connected mode (Connected Mode), otherwise it is in the RRC idle mode (Idle Mode).

Hereinafter, the RRC state and the RRC connection method of the UE will be described. The RRC state refers to whether or not the RRC of the UE is in a logical connection with the RRC of the E-UTRAN. If the RRC state is connected, the RRC_CONNECTED state is called, and the RRC_IDLE state is not connected. Since the UE in the RRC_CONNECTED state has an RRC connection, the E-UTRAN can grasp the existence of the UE in units of cells, and thus can effectively control the UE. On the other hand, the UE in the RRC_IDLE state cannot identify the existence of the UE by the E-UTRAN, and the core network manages the unit in a larger tracking area (TA) unit than the cell. That is, the terminal in the RRC_IDLE state is only detected whether the terminal exists in a larger area than the cell, and the terminal must transition to the RRC_CONNECTED state in order to receive a normal mobile communication service such as voice or data. Each TA is identified by a tracking area identity (TAI). The terminal may configure a TAI through a tracking area code (TAC), which is information broadcast in a cell.

When the user first turns on the power of the terminal, the terminal first searches for an appropriate cell, then establishes an RRC connection in the cell, and registers the terminal's information in the core network. Thereafter, the terminal stays in the RRC_IDLE state. The terminal staying in the RRC_IDLE state (re) selects a cell as needed and looks at system information or paging information. This is called camping on the cell. When it is necessary to establish an RRC connection, the UE staying in the RRC_IDLE state makes an RRC connection with the RRC of the E-UTRAN through an RRC connection procedure and transitions to the RRC_CONNECTED state. There are several cases in which a UE in RRC_IDLE state needs to establish an RRC connection. For example, a user's call attempt, a data transmission attempt, etc. are required or a paging message is received from E-UTRAN. Reply message transmission, and the like.

A non-access stratum (NAS) layer located above the RRC layer performs functions such as session management and mobility management.

The following describes the NAS layer shown in FIG. 3 in detail.

ESM (evolved Session Management) belonging to the NAS layer performs functions such as default bearer management and dedicated bearer management, and is responsible for controlling the terminal to use the PS service from the network. The default bearer resource is characterized in that it is allocated from the network when it is connected to the network when it first accesses a specific Packet Data Network (PDN). At this time, the network allocates an IP address usable by the terminal so that the terminal can use the data service, and also allocates QoS of the default bearer. LTE supports two types of bearer having a guaranteed bit rate (GBR) QoS characteristic that guarantees a specific bandwidth for data transmission and reception, and a non-GBR bearer having a best effort QoS characteristic without guaranteeing bandwidth. In case of Default bearer, Non-GBR bearer is assigned. In the case of a dedicated bearer, a bearer having a QoS characteristic of GBR or non-GBR may be allocated.

The bearer allocated to the terminal in the network is called an evolved packet service (EPS) bearer, and when the EPS bearer is allocated, the network allocates one ID. This is called EPS Bearer ID. One EPS bearer has a QoS characteristic of a maximum bit rate (MBR) or / and a guaranteed bit rate (GBR).

5 is a flowchart illustrating a random access procedure in 3GPP LTE.

The random access procedure is used for the UE to get UL synchronization with the base station or to be allocated UL radio resources.

The UE receives a root index and a physical random access channel (PRACH) configuration index from the eNodeB. Each cell has 64 candidate random access preambles defined by a Zadoff-Chu (ZC) sequence, and the root index is a logical index for the UE to generate 64 candidate random access preambles.

Transmission of the random access preamble is limited to a specific time and frequency resource for each cell. The PRACH configuration index indicates a specific subframe and a preamble format capable of transmitting the random access preamble.

The UE sends the randomly selected random access preamble to the eNodeB. The UE selects one of the 64 candidate random access preambles. Then, the corresponding subframe is selected by the PRACH configuration index. The UE transmits the selected random access preamble in the selected subframe.

Upon receiving the random access preamble, the eNodeB sends a random access response (RAR) to the UE. The random access response is detected in two steps. First, the UE detects a PDCCH masked with random access-RNTI (RA-RNTI). The UE receives a random access response in a medium access control (MAC) protocol data unit (PDU) on the PDSCH indicated by the detected PDCCH.

6 shows a connection process in a radio resource control (RRC) layer.

As shown in FIG. 6, the RRC state is shown depending on whether the RRC is connected. The RRC state refers to whether or not an entity of the RRC layer of the UE is in a logical connection with an entity of the RRC layer of the eNodeB. When the RRC state is connected, the RRC state is referred to as an RRC connected state. The non-state is called the RRC idle state.

Since the UE in the connected state has an RRC connection, the E-UTRAN may determine the existence of the corresponding UE in units of cells, and thus may effectively control the UE. On the other hand, the UE in the idle state (idle state) can not be identified by the eNodeB, the core network (core network) is managed by the tracking area (Tracking Area) unit that is larger than the cell unit. The tracking area is a collection unit of cells. That is, the idle state (UE) is determined only in the presence of the UE in a large area, and in order to receive a normal mobile communication service such as voice or data, the UE must transition to the connected state (connected state).

When a user first powers up a UE, the UE first searches for an appropriate cell and then stays in an idle state in that cell. When the UE staying in the idle state needs to establish an RRC connection, the UE establishes an RRC connection with the RRC layer of the eNodeB through an RRC connection procedure and transitions to an RRC connected state. .

There are several cases in which the UE in the idle state needs to establish an RRC connection. For example, a user's call attempt or uplink data transmission is required, or a paging message is received from EUTRAN. In this case, the response message may be transmitted.

In order to establish an RRC connection with the eNodeB, the UE in an idle state must proceed with an RRC connection procedure as described above. The RRC connection process is largely a process in which a UE sends an RRC connection request message to an eNodeB, an eNodeB sends an RRC connection setup message to the UE, and a UE completes RRC connection setup to the eNodeB. (RRC connection setup complete) message is sent. This process will be described in more detail with reference to FIG. 6 as follows.

1) When a UE in idle mode attempts to establish an RRC connection due to a call attempt, a data transmission attempt, or a response to an eNodeB's paging, the UE first sends an RRC connection request message. Send to eNodeB.

2) When the RRC connection request message is received from the UE, the eNB accepts the RRC connection request of the UE when the radio resources are sufficient, and transmits an RRC connection setup message, which is a response message, to the UE. .

3) When the UE receives the RRC connection setup message, it transmits an RRC connection setup complete message to the eNodeB. When the UE successfully transmits an RRC connection establishment message, the UE establishes an RRC connection with the eNodeB and transitions to the RRC connected mode.

Group Communications and the Evolution of MBMS

7 is an example of a non-roaming architecture model for Group Communication System Enablers for LTE (GCSE_LTE). The GCS Application Server (AS) may use the enablers provided by the 3GPP system to provide Group Communication Service (GCS). Such enablers are referred to as Group Communication System Enablers (GCSE). The GCS AS supports GC1 signaling with the UE, receives unicast uplink data from the UE, transmits data to terminals belonging to the group using unicast or MBMS, and transmits application level session information to the PCRF through the Rx interface. It also supports functions such as session continuity procedure between unicast and MBMS.

8 shows a media traffic delivery procedure of unicast and MBMS. Referring to FIG. 8, when the GCS AS transmits group communication-related media to UEs belonging to the same group, the GCS AS may transmit unicast to some UEs and MBMS to other UEs. Of course, the media can be transmitted to all UEs belonging to the same group by unicast or MBMS. Although UE-2, UE-3, and UE-4 are connected to eNB-2, which is the same eNB, different downlink transmission schemes between these UEs may be used. For example, UE-2 is located in an area where the MBMS signal strength is weak, and thus receives the group communication-related media by unicast rather than MBMS. In addition, for details regarding GCSE_LTE, 3GPP TS 23.468 shall apply mutatis mutandis.

When MBMS downlink media transmission is used, the broadcast area may be pre-configured by the GCS AS, and the number of group member UEs in any area (within a cell or a collection of cells) is sufficient. If it is determined that the size is large, it may be dynamically determined to transmit downlink media for this region by MBMS. If the GCS AS determines the transmission of the MBMS scheme for a group, the Activate MBMS bearer procedure as shown in FIG. 9 is performed. The Activate MBMS bearer procedure is a procedure for requesting resource allocation for an MBMS bearer from a Broadcast Multicast Service Center (BM-SC).

Referring to FIG. 9, in step S901, the GCS AS requests the BM-SC to activate MBMS Bearer Request including a Temporary Mobile Group Identity (TMGI) indicating a MBMS bearer to be started, FlowID, QoS, MBMS broadcast area, start time, and the like. Send a message. TMGI may optionally be included, and FlowID is included only when TMGI is included. If the FlowID is included, the BM-SC associates the FlowID with the TMGI for the MBMS broadcast area. QoS is mapped to appropriate QoS parameters of the MBMS bearer. The MBMS broadcast area carries the MBMS service area. When GCS AS requests BM-SC to transmit MBMS downlink traffic, it includes MBMS broadcast area as a parameter, which is a unit of MBMS service area. The Activate MBMS Bearer Request message sent by the GCS AS to the BM-SC is in the form of a GCS-Action-Request (GAR) command of 3GPP TS 29.468. It may be a format such as 2.

TABLE 2

MBMS-Bearer-Request :: = <AVP Header: 3504> {MBMS-StartStop-Indication} [TMGI] [MBMS-Flow-Identifier] [QoS-Information] [MBMS-Service-Area] [MBMS-Start-Time] [MB2U-Security] * [AVP]

In step S902, the BM-SC allocates resources. In this regard, if TMGI is included in the request, the BM-SC must determine whether the GCS AS is authorized. If the TMGI is not authenticated, the BM-SC rejects the request. If TMGI is not included in the request, the BM-SC assigns a value not used for TMGI. If the FlowID is not included in the request, the BM-SC assigns a FlowID value corresponding to the TMGI and MBMS broadcast area. If the MBMS bearer with the same TMGI and FlowID but different MBMS broadcast area is already activated, the BM-SC rejects the request. If an MBMS bearer of the same TMGI and another FlowID is already active, the BM-SC ensures that the MBMS broadcast area of this MBMS bearer does not overlap with the MBMS broadcast areas corresponding to the existing MBMS bearer of the same TMGI. . The BM-SC allocates MBMS resources. In step S903, the BM-SC transmits an Activate MBMS Bearer Response message to the GCS AS. The Activate MBMS Bearer Response message may include TMGI, FlowID (echoed back if initially included in the request, or allocated by BM-SC), service description, BM-SC IP address, port number for user plane, expiration time, etc. Can be. The service description includes the MBMS bearer associated with the configuration information defined in TS 26.346. (Eg, infoBindling element containing serviceArea and radiofrequency) The expiration time is included only if the BM-SC has assigned a TMGI.

On the other hand, the MBMS is being modified / evolved to be used as a method of group communication for public safety, and one of the directions is that the transmission of the MBMS method is a regional unit (eg, cell) in a range other than the conventional MBMS Service Area unit. Unit). (See 3GPP SP-140883 for details on other directions.) In this regard, the GMS AS needs to be allowed to request an MBMS bearer based on the MBMS service area or the MBMS service of any network where the GCS AS provides MBMS service. It may be necessary to know the area configuration. These needs may be satisfied through the MBMS bearer generation method based on the list transmission of E-UTRAN Cell Global Identifiers (ECGI). As an example, the MBMS bearer initialization procedure illustrated in FIG. 10 is possible.

Referring to FIG. 10, in step S1001, when the GCS AS wants to activate an MBMS bearer on MB2, the GCS AS transmits an Activate MBMS Bearer Request message to the BM-SC. In this regard, specific contents are the same as those described above in step S901 of FIG. 9. Note that the MBMS broadcast area parameter may contain a list of MBMS service areas or a list of cell identifiers (ie, ECGI). If the MBMS broadcast area parameter includes a list of cell identifiers, in step S1002, the BM-SC maps the received cell identifiers to a set of MBMS service areas. In step S1002, the BM-SC maps ECGIs to SAIs and determines an MBMS gateway. In S1003, the BM-SC transmits a Session Start message to the MBMS-GW (s) including the ECGIs list and related parameters previously defined. In step S1004, the MBMS-GW transmits a Session Start message including the ECGIs list and related parameters previously defined to the MME. In step S1005, the MME transmits a Session Start message including the ECGIs list and related parameters previously defined to the MCE. In step S1006, the MCE maps the SAI list to the MBSFN list. Then, based on the ECGI list, unused MBSFNs are removed. The MCE allocates resources in the MBSFN selected for the MBSFN bearer. The MCE forms a list of all ECGIs in the selected MBSFN to which the MBMS bearer will be broadcast. In step S1007, the MCE sends a Session Start response message including a list of ECGIs and conventional parameters to which the MBMS bearer is to be broadcast, to the MME. In step S1008, the MME sends a Session Start response message including a list of ECGIs and conventional parameters to which the MBMS bearer is to be broadcast, to the MBMS-GW. In step S1009, the MBMS-GW sends a Session Start response message including a list of ECGIs and conventional parameters, to which the MBMS bearer is to be broadcast, to the BM-SC. In step S1010, the BM-SC sends an Activate MBMS Bearer Response message to the GCS AS. The detailed description of this message is the same as that of step S903 with respect to FIG. If the BM-SC receives the ECGI list in the Activate MBMS Bearer Request message, the BM-SC sends the ECGI list in the Activate MBMS Bearer Response message. If the BM-SC chooses to transmit the Activate MBMS Bearer Response message before receiving the Session Start response message, the BM-SC must include the ECGIs list in the Activate MBMS Bearer Request message.

11 is an illustration of an MBMS bearer notification procedure. Referring to FIG. 11, when the MCE determines in step S1101 that the list of cells broadcasting MBMS has changed, the MCE forms a list of all broadcast ECGIs. In step S1102, the MCE transmits a Session Notification message including a list of TMGI, FlowID, and ECGIs to the MME. This message is sent from the MME to the MBMS-GW (step S1103), and from the MBMS-GW to the BM-SC (step S1104). In step S1105, the BM-SC sends an MBMS Delivery Status Indication message to the GCS AS indicating that there is a change in the MBMS broadcast area.

12 illustrates a logical structure of a multi-cell / multicast coordination entity (MCE). The MCE is a logical entity and can be configured as part of another network node. The MCE performs the function of allocating radio resources used by all eNBs in admission control and MBSFN areas. If there is not enough radio resources or resources are preempted by the radio bearer of the ongoing MBMS service according to the ARP, the MCE does not establish a radio bearer for the new MBMS service. Here, the allocation of radio resources includes radio configurations such as time / frequency resource allocation, modulation and coding schemes. The MCE decides whether to use SC-PTM or MBSFN. The MCE performs counting and acquisition of counting results for the MBMS service. The MCE performs resume / stop of the MBMS session in the MBSFN area. (E.g., ARP and / or the counting results for the corresponding MBMS service (s)),

According to the MBMS bearer initialization procedure described above, when there are a lot of requests for stopping MBMS transmission or changing downlink transmission schemes in public safety (Public Safety terminals or terminals participating in group communication), The location may be changed frequently according to the occurrence of an incident / accident, and thus, the GCS AS may change the downlink traffic transmission method for a specific cell frequently), unnecessary signaling exchange, and waste of network resources. This will be described with reference to FIG. 13. Referring to FIG. 13, MBMS SAI # 1 is composed of three MBSFNs. Each MBSFN consists of 10 cells, ECGI # 1 ~ ECGI # 5 is eNB # 1, ECGI # 6 ~ ECGI # 10 is eNB # 2, ECGI # 11 ~ ECGI # 15 is eNB # 3, ECGI # 16 ~ It is assumed that ECGI # 20 is eNB # 4, ECGI # 21 to ECGI # 25 are eNB # 5, and ECGI # 26 to ECGI # 30 are cells of eNB # 6. In addition, it is assumed that the MCE maintains the information shown in Table 3 through the M2 setup procedure with the configuration and the eNB. For M2 setup procedure between eNB and MCE, refer to 3GPP TS 36.443.

TABLE 3

eNB	ECGI	MBSFN	MBMS SAI
#One	#One	#One	#One
#One	#2	#One	#One
#One	# 3	#One	#One
#One	#4	#One	#One
#One	# 5	#One	#One
#2	# 6	#One	#One
#2	# 7	#One	#One
#2	#8	#One	#One
#2	# 9	#One	#One
#2	# 10	#One	#One
# 3	# 11	#2	#One
# 3	# 12	#2	#One
# 3	# 13	#2	#One
# 3	# 14	#2	#One
# 3	# 15	#2	#One
#4	# 16	#2	#One
#4	# 17	#2	#One
#4	# 18	#2	#One
#4	# 19	#2	#One
#4	# 20	#2	#One
# 5	# 21	# 3	#One
# 5	# 22	# 3	#One
# 5	# 23	# 3	#One
# 5	# 24	# 3	#One
# 5	# 25	# 3	#One
# 6	# 26	# 3	#One
# 6	# 27	# 3	#One
# 6	# 28	# 3	#One
# 6	# 29	# 3	#One
# 6	# 30	# 3	#One

In such a situation, when the GCS AS decides to transmit MBMS for ECGI # 7 to ECGI # 18, the GCS AS provides MBMS SAI # 1 and ECGI # 7 to ECGI # 18 when the MBMS request is sent to the BM-SC. . Receiving this, the MCE extracts MBSFN # 1, MBSFN # 2, and MBSFN # 3 based on MBMS SAI # 1 and constructs an MBSFN list. The MCE deletes MBSFN # 3 from the MBSFN list based on an ECGI list, that is, ECGI # 7 to ECGI # 18. The MCE allocates resources for the MBMS bearer only for the last selected MBSFN # 1 and MBSFN # 2. Specifically, the MBMS Session Start is requested to the eNB # 2, the eNB # 3, and the eNB # 4 so that the MBMS transmission can be made to the ECGI # 7 to the ECGI # 18. In this case, since the MBMS Session Start request includes MBMS Service Area information, the eNB allocates resources for the MBMS bearer to all cells belonging to the MBMS Service Area. As a result, eNB # 2 performs ECGI # 6 to ECGI # 10, eNB # 3 performs ECGI # 11 to ECGI # 15, and eNB # 4 performs MBMS transmission on ECGI # 16 to ECGI # 20. In this case, the MCE constructs a list of ECGIs for which MBMS transmission will occur, that is, a list including ECGI # 6 to ECGI # 20. It is included when sending a Session Start response message to the MME, which is sent to the GCS AS via MBMS GW and BM-SC.

Here, if the GCS AS determines the transition from the MBMS scheme to the unicast scheme for the ECGI # 10 (for example, when the number of group member UEs falls below a certain threshold in ECGI # 10), the BM-SC informs the BM-SC. For ECGI # 10, a request for canceling a resource allocated for the MBMS bearer, that is, a request for stopping MBMS transmission for ECGI # 10, may be transmitted. However, since such a cell-by-cell transmission stop request is not allowed, the MCE cannot request the eNB # 2 to stop MBMS transmission for ECGI # 10. Therefore, the MCE transmits a response message notifying the failure or rejection of the received MBMS transmission stop request to the GCS AS. As mentioned above, in Public Safety, when a large number of GCS AS sends this meaningless MBMS transmission stop request message to the BM-SC, unnecessary signaling exchanges are not only performed by MBMS-related nodes (ie, BM-SC, MBMS GW, MCE). MME also wastes network resources.

Example

Hereinafter, an embodiment of the present invention for solving such a problem will be described. The MCE according to an embodiment of the present invention may receive a Session Start message including a Service Area Identities (SAI) and a first ECGI list, and configure an MBSFN list using the SAI. And, based on the first ECGI list, the MBSFN which does not need to allocate resources can be removed from the MBSFN list. The resource allocation for the MBMS bearer may be allocated based on the MBSFN list and the first ECGI list from which the MBSFN has not been allocated. At this time, resource allocation is performed by transmitting an MBMS Session Start request including MBMS Service Area information to the eNB by the MCE as described above. The eNB allocates resources according to MBMS Service Area information. Thereafter, the MCE may configure a second ECGI list on which MBMS transmission is to be performed through resource allocation. The second ECGI list may be transmitted to a network (delivered to a Group Communication Service Application Server (GCS AS) through an MME, an MBMS gateway, and a Broadcast Multicast Service Center (BM-SC)).

Here, in the case where the MCE is not capable of Single Cell Point To Multiploint (SC-PTM) or if SC-PTM is available but decides to use the MBSFN transmission scheme, the second ECGI list may contain ECGI grouping information. It may include.

The ECGI grouping information may be group / collection information of cells in which MBMS transmission and suspension always occur together among cells. A transmission stop request for some of the cells indicated in such ECGI grouping information may not be allowed. Alternatively, a change of the transmission scheme from MBMS to unicast may not be allowed for some of the cells indicated in the ECGI grouping information. That is, the GCS AS does not determine to switch the downlink traffic transmission scheme from the MBMS scheme to the unicast scheme for only some of the cells belonging to the same group. Or, the GCS AS does not make a request to the BM-SC to stop MBMS transmission for only some of the cells belonging to the same group. Applying this in the case of FIG. 13, the MCE is ECGI # 6: Index # 1, ECGI # 7: Index # 1, ECGI # 8: Index # 1, ECGI # 9: Index # 1, ECGI # 10: Index #. 1, ECGI # 11: Index # 2, ECGI # 12: Index # 2, ECGI # 13: Index # 2, ECGI # 14: Index # 2, ECGI # 15: Index # 2, ECGI # 16: Index # 3, ECGI grouping information in index format such as ECGI # 17: Index # 3, ECGI # 18: Index # 3, ECGI # 19: Index # 3, ECGI # 20: Index # 3 is transmitted to the GCS AS, and the GCS AS is the same. For some cells among the cells belonging to the group, for example, only some cells of ECGI # 6 to ECGI # 10 do not decide to stop the MBMS transmission or request the BM-SC to stop the transmission.

The ECGI grouping information may be delivered in a manner other than a method in which an index (or group ID) is assigned to the illustrated ECGI. For example, when the broadcasting ECGI list is included, the grouped ECGIs may be included in the sub-list unit to inform that the cells included in each sub-list belong to the same group. Alternatively, when the broadcasting ECGI list is included, whenever a ECGI of a cell belonging to the same group ends, a separator may be inserted to indicate that the cells separated by the separator belong to the same group. In addition, information indicating that MBMS transmission can be stopped only in units of grouped cells (that is, information indicating that MBMS transmission can be stopped for all grouped cells), and only some cells of the grouped cells indicate that MBMS transmission cannot be stopped. One or more pieces of information, or information indicating that a cell grouped with respect to the grouping information belongs to a cell belonging to the same eNB, may be transmitted together with the ECGI grouping information.

When SC-PTM is available, the MCE may determine whether to use the MBSFN transmission scheme in consideration of the relationship between the number of cells of the first ECGI list and the number of cells of the second ECGI list. For example, if the number of cells of the first ECGI list for the number of cells of the second ECGI list is greater than a preset value, the MCE may decide to use the MBSFN transmission scheme although SC-PTM is possible.

14 shows an example of the operation of the MCE in connection with the above-described embodiment. Referring to FIG. 14, in step S1401, the MCE determines whether SC-PTM transmission is possible. If SC-PTM transmission is possible, it is determined whether to transmit to SC-PTM (step S1402). If it is determined to transmit to the SC-PTM, and transmits the MBMS SESSION START REQUEST to the eNB (s) (S1403). At this time, the information according to the SC-PTM transmission is included. For details, the content of TS 36.443 shall apply mutatis mutandis. In step S1404, MCE receives a response from the eNB (s) that sent the request and determines whether to finally perform the SC-PTM transmission based on this. For example, if a response from the eNB that SC-PTM transmission is impossible due to a problem such as a radio resource, the MCE determines to use the MBSFN transmission scheme. If it is determined that the SC-PTM transmission is finally performed, step S1405 is performed. In step S1405, a broadcasting ECGI list, which is information about a cell on which actual MBMS transmission is to be made, is reflected by reflecting the SC-PTM transmission decision. This can be transmitted in units of cells rather than in units of eNBs, and may reflect cell lists requested for MBMS transmission. In addition, at this time, the MCE determines not to provide grouping information of the cell. In addition, information indicating that SC-PTM transmission is possible may be included in a Session Start Response message.

If the MCE cannot transmit the SC-PTM or if the MCE determines the MBSFN transmission even though the SC-PTM transmission is possible, the MCE decides to transmit the MBSFN. In this case, the actual MBMS transmission is reflected by the MBSFN transmission decision. It configures a broadcasting ECGI list which is information on the cell to be formed. This reflects the cells in which the MBMS transmission is controlled at each eNB. In addition, at this time, the MCE determines to provide grouping information of the cell. In addition, information indicating that SC-PTM transmission is not possible (or MBSFN transmission only) may be included in the Session Start Response message. If the MCE determines the MBSFN transmission method despite SC-PTM transmission, information indicating that SC-PTM transmission is possible may be included in the Session Start Response message. The reason for notifying that SC-PTM transmission is possible is to perform MBMS transmission in units of eNBs for this request, but to inform GCS AS that MBMS transmission is possible in units of cells. In the above description, MCE capable of SC-PTM transmission may mean that not only MCE but also eNBs controlled by MCE have SC-PTM transmission capability. Although the MCE enables the SC-PTM transmission, the reason for determining the MBSFN transmission scheme may be that a range of a cell that is requested for MBMS transmission occupies a certain threshold or more in comparison to the range of a cell to be covered when transmitting in units of eNBs. For example, as shown in FIG. 13, ECGI # 7 to ECGI # 18 are compared to (12/15) * 100 = 80% of a total of 15 cells covered by eNB # 2, eNB # 3, and eNB # 4. Corresponding. Accordingly, if the threshold value is 80%, the MCE may determine the MBSFN transmission. If the threshold value is 90%, the MCE may determine the SC-PTM transmission.

In the above description, the cell-related group / collection information has been described as being delivered to the GCS AS, in contrast, only the BM-SC may be delivered. In this case, when the GCS AS sends a request to the BM-SC to stop MBMS transmission for only some of the cells belonging to the same group, the BM-SC may transmit a response message indicating the failure or rejection to the GCS AS. At this time, it may include cause information (eg, partial MBMS stop is not possible) indicating a reason for failure or rejection. In addition, instead of providing information by the MCE as described above, the information may be configured in the BM-SC or the GCS AS. When the GCS AS requests to stop transmitting MBMS for all cells belonging to the same group / collection, instead of including all ECGI lists for the cells, grouping related information about the cells (eg, index or group ID) is obtained. It can also be provided to the GCS AS.

In the present invention, the GCS AS refers to various application servers or functions that provide services in relation to group communication and / or public safety. Examples can be MCPTT AS, Public Safety AS, ProSe Function, and so on.

15 is a diagram showing the configuration of a preferred embodiment of a terminal device and a network node device according to an example of the present invention.

The terminal device 100 according to the present invention with reference to FIG. 15 may include a transceiver 110, a processor 120, and a memory 130. The transceiver 110 may be configured to transmit various signals, data and information to an external device, and to receive various signals, data and information to an external device. The terminal device 100 may be connected to an external device by wire and / or wirelessly. The processor 120 may control the overall operation of the terminal device 100, and may be configured to perform a function of the terminal device 100 to process and process information to be transmitted and received with an external device. In addition, the processor 120 may be configured to perform a terminal operation proposed in the present invention. The memory 130 may store the processed information for a predetermined time and may be replaced with a component such as a buffer (not shown).

Referring to FIG. 15, the network node apparatus 200 according to the present invention may include a transceiver 210, a processor 220, and a memory 230. The transceiver 210 may be configured to transmit various signals, data and information to an external device, and to receive various signals, data and information to an external device. The network node device 200 may be connected to an external device by wire and / or wirelessly. The processor 220 may control the overall operation of the network node device 200, and may be configured to perform a function of calculating and processing information to be transmitted / received with an external device. In addition, the processor 220 may be configured to perform the network node operation proposed in the present invention. The memory 230 may store the processed information for a predetermined time and may be replaced with a component such as a buffer (not shown).

In addition, the specific configuration of the terminal device 100 and the network device 200 as described above, may be implemented so that the above-described matters described in various embodiments of the present invention can be applied independently or two or more embodiments are applied at the same time, overlapping The description is omitted for clarity.

Embodiments of the present invention described above may be implemented through various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

For implementation in hardware, a method according to embodiments of the present invention may include one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), and Programmable Logic Devices (PLDs). It may be implemented by field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, the method according to the embodiments of the present invention may be implemented in the form of an apparatus, procedure, or function for performing the above-described functions or operations. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.

The detailed description of the preferred embodiments of the invention disclosed as described above is provided to enable any person skilled in the art to make and practice the invention. Although the above has been described with reference to the preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. I can understand that you can. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Various embodiments of the present invention as described above have been described with reference to the 3GPP system, but may be applied to various mobile communication systems in the same manner.

Claims (12)

1. In the method of transmitting and receiving a signal related to MBMS (Multimedia Broadcast Multicast Services) of MCE (Multi-cell / Multicast Coordination Entity) in a wireless communication system,

   Receiving a Session Start message including a Service Area Identities (SAI) and a first ECGI list;

   Constructing an MBSFN list using the SAI;

   Removing from the MBSFN list an MBSFN that does not need to allocate resources based on the first ECGI list;

   Allocating a resource for an MBMS bearer based on the MBSFN list from which the MBSFN has not been allocated and the first ECGI list;

   Constructing a second ECGI list to which MBMS transmission is to be performed by the resource allocation; And

   Transmitting the second ECGI list to a network;

   Including;

   If the MCE is not capable of Single Cell Point To Multiploint (SC-PTM) or if SC-PTM is enabled but decides to use the MBSFN transmission scheme, the second ECGI list may contain ECGI grouping information. MBMS-related signal transmission and reception method comprising.
2. The method of claim 1,

   When the SC-PTM is available, the MCE determines whether to use the MBSFN transmission scheme in consideration of the relationship between the number of cells in the first ECGI list and the number of cells in the second ECGI list. .
3. The method of claim 2,

   The MCE, if the number of cells of the first ECGI list for the number of cells of the second ECGI list is larger than a preset value, SC-PTM is possible, but determines to use the MBSFN transmission method, MBMS-related signal transmission and reception method .
4. The method of claim 1,

   The request to stop transmission for some of the cells indicated in the ECGI grouping information is not allowed.
5. The method of claim 1,

   The change of the transmission scheme from MBMS to unicast is not allowed for some of the cells indicated in the ECGI grouping information.
6. The method of claim 1,

   The second ECGI list is transmitted to a Group Communication Service Application Server (GCS AS) through a Mobility Management Entity (MME), an MBMS Gateway, and a Broadcast Multicast Service Center (BM-SC).
7. In the multi-cell / multicast coordination entity (MCE) device for transmitting and receiving MBMS (Multimedia Broadcast Multicast Services) related signals in a wireless communication system,

   A transceiver; And

   Includes a processor,

   The processor receives a Session Start message including a Service Area Identities (SAI) and a first ECGI list, constructs an MBSFN list using the SAI, and allocates resources based on the first ECGI list. Removes the MBSFN from the MBSFN list, which do not need to be allocated, allocates resources for the MBMS bearer based on the MBSFN list and the first ECGI list from which the MBSFN has not been allocated, and allocates the MBMS through the resource allocation. Construct a second ECGI list to be transmitted, transmit the second ECGI list to a network,

   If the MCE is not capable of Single Cell Point To Multiploint (SC-PTM) or if SC-PTM is enabled but decides to use the MBSFN transmission scheme, the second ECGI list may contain ECGI grouping information. Included, MCE device.
8. The method of claim 7, wherein

   The MCE apparatus determines whether to use the MBSFN transmission scheme in consideration of the relationship between the number of cells of the first ECGI list and the number of cells of the second ECGI list when the SC-PTM is available.
9. The method of claim 8,

   The MCE apparatus, if the number of cells of the first ECGI list for the number of cells of the second ECGI list is greater than a predetermined value, SC-PTM is possible, but determines to use the MBSFN transmission scheme.
10. The method of claim 7, wherein

    MCE device is not allowed to stop transmission for some of the cells indicated in the ECGI grouping information.
11. The method of claim 7, wherein

    MCE apparatus is not allowed to change the transmission scheme from MBMS to unicast for some of the cells indicated in the ECGI grouping information.
12. The method of claim 7, wherein

    The second ECGI list is delivered to a Group Communication Service Application Server (GCS AS) through a Mobility Management Entity (MME), an MBMS Gateway, and a Broadcast Multicast Service Center (BM-SC).

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