WO2017171250A2

WO2017171250A2 - Method for allocating pc5 resource in wireless communication system and apparatus therefor

Info

Publication number: WO2017171250A2
Application number: PCT/KR2017/002214
Authority: WO
Inventors: 김동수; 김래영
Original assignee: 엘지전자(주)
Priority date: 2016-03-29
Filing date: 2017-02-28
Publication date: 2017-10-05
Also published as: WO2017171251A1; WO2017171250A3

Abstract

A method for allocating a PC5 resource may comprise the steps of: transmitting, to an eNB, a first sidelink BSR on the amount of first sidelink data and a second sidelink BSR on the amount of second sidelink data that can be transmitted from a sidelink buffer, wherein the first sidelink BSR indicates a service type of the first sidelink data, and the second sidelink BSR indicates a service type of the second sidelink data; and receiving, from the eNB, a PC5 resource for transmission of the first and/or second sidelink data, allocated on the basis of an LCG ID included in each of the first and second sidelink BSRs.

Description

PC5 resource allocation method in wireless communication system and apparatus therefor

The present invention relates to a method for an UE to be allocated PC5 resources from an eNB in a wireless communication system, and an apparatus therefor.

Mobile communication systems have been developed to provide voice services while ensuring user activity. However, the mobile communication system has expanded not only voice but also data service. Currently, the explosive increase in traffic causes shortage of resources and the demand for faster services. Therefore, a more advanced mobile communication system is required. have.

The requirements of the next generation of mobile communication systems will be able to accommodate the explosive data traffic, dramatically increase the data rate per user, greatly increase the number of connected devices, very low end-to-end latency, and high energy efficiency. It should be possible. Dual connectivity, Massive Multiple Input Multiple Output (MIMO), In-band Full Duplex, Non-Orthogonal Multiple Access (NOMA), Super Various technologies such as wideband support and device networking have been studied.

An object of the present specification is to propose a method of first allocating / selecting PC5 resources for a specific data packet in consideration of the service type and / or PPPP of each data packet when there is insufficient PC5 resources that can be allocated for data packet transmission. .

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, in a method in which a user equipment (UE) is allocated a PC5 resource from an evolved-NodeB (eNB) in a wireless communication system, a first sidelink for the amount of first sidelink data that can be transmitted in a sidelink buffer Sending a second Sidelink BSR for the amount of Buffer Status Report (BSR) and second Sidelink data to the eNB; The first Sidelink BSR indicates a service type of the first Sidelink data, and the second Sidelink BSR indicates a service type of the second Sidelink data, respectively, included in the first and second Sidelink BSRs from the eNB. Allocating PC5 resources for the first and / or second Sidelink data transmission based on a Logical Channel Group (LCG) Identifier (LCG); Including the PC5 resources, if the LCG ID of the first and second Sidelink BSR is different, is allocated preferentially for the sidelink data transmission corresponding to the Sidelink BSR including the LCG ID having a high priority, When the LCG IDs of the first and second Sidelnk BSRs are the same, the first and second Sidelnk BSRs may be preferentially allocated for the first or second Sidelink data transmission based on the service type.

In addition, the PC5 resource represents a radio resource allocated for Sidelink data transmission through a PC5 interface, and the PC5 interface may correspond to an interface of a UE to a UE for sidelink communication and sidelink discovery.

In addition, the first and second Sidelink BSR may be configured with one same Sidelink BSR or may be configured with different Sidelink BSRs different from each other.

In addition, the LCG ID may be an identifier for identifying a group of logical channels for which a buffer status is reported through the first or second sidelink BSR.

In addition, the LCG ID is mapped to at least one Proximity Service (ProSe) per Packet Priority (PPPP), and the PPPP is used to indicate a priority of a protocol data unit including the first or second sidelink data. It may be a priority parameter.

In addition, the LCG ID may be mapped to an ID of a Proseimity Service (Prose) destination which is a transmission destination of the first or second sidelink data.

The method of allocating the PC5 resource may include receiving service type information indicating which service type the PC5 resource allocated from the eNB is, when the LCG IDs of the first and second Sidelnk BSRs are the same; And transmitting sidelink data of a service type indicated through the service type information using the allocated PC5 resource. It may further include.

In addition, the service type may correspond to a ProSe (Proximity Service) or V2X service.

In addition, another embodiment of the present invention, in a user equipment (UE) allocated PC5 resources from an evolved-NodeB (eNB) in a wireless communication system, a communication module (communication module) for transmitting and receiving signals; And a processor controlling the communication module. The processor may include: transmitting, to the eNB, a first Sidelink Buffer Status Report (BSR) for the amount of first Sidelink data that can be transmitted from a Sidelink buffer and a second Sidelink BSR for the amount of second Sidelink data, The first Sidelink BSR indicates a service type of the first Sidelink data, and the second Sidelink BSR indicates a service type of the second Sidelink data, respectively, the LCG included in the first and second Sidelink BSRs from the eNB. If the PC5 resources for the first and / or second Sidelink data transmission is allocated based on an Logical Channel Group (ID) identifier (ID), the PC5 resources, if the LCG ID of the first and second Sidelink BSR is different, It is preferentially allocated for Sidelink data transmission corresponding to the Sidelink BSR including the LCG ID having a high priority. When the LCG IDs of the first and second Sidelnk BSRs are the same, the first service is based on the service type. It may be assigned preferentially to claim 2 Sidelink data transmission.

In addition, the processor receives service type information indicating which service type the PC5 resource allocated from the eNB is, and the service type information indicated through the service type information using the allocated PC5 resource. Sidelink data can be transmitted.

According to an embodiment of the present invention, since the eNB allocates / selects the PC5 resource based on whether the PC5 resource requested through the BSR is used for the ProSe application or for the V2X service, efficient PC5 resource use per service is achieved. There is an effect that it is possible.

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

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, included as part of the detailed description in order to provide a thorough understanding of the present invention, provide embodiments of the present invention and together with the description, describe the technical features of the present invention.

1 is a diagram briefly illustrating an EPS (Evolved Packet System) to which the present invention may be applied.

2 shows an example of a network structure of an evolved universal terrestrial radio access network (E-UTRAN) to which the present invention can be applied.

3 illustrates the structure of an E-UTRAN and an EPC in a wireless communication system to which the present invention can be applied.

4 shows a structure of a radio interface protocol between a terminal and an E-UTRAN in a wireless communication system to which the present invention can be applied.

5 is a diagram exemplarily illustrating a structure of a physical channel in a wireless communication system to which the present invention can be applied.

6 is a diagram for explaining a contention based random access procedure in a wireless communication system to which the present invention can be applied.

7 illustrates a reference architecture for PC5 based V2X to which the present invention may be applied.

FIG. 8 is a diagram illustrating the structure of a Buffer Status Report MAC control element in a wireless communication system to which the present invention can be applied.

9 is a diagram illustrating a structure of a sidelink buffer status report MAC control element in a wireless communication system to which the present invention can be applied.

FIG. 10 is a diagram illustrating a mapping relationship between a destination, an LCG, and a PPPP in a BSR reporting procedure of a UE to which the present invention can be applied.

11 is a flowchart illustrating a PC5 resource allocation method according to an embodiment of the present invention.

12 is a diagram illustrating a transmission resource pool and a transmission resource pool selection operation of a UE that can be applied to the present invention.

13 is a flowchart illustrating a PC5 resource pool selection method of a UE according to an embodiment of the present invention.

14 illustrates a block diagram of a communication device according to an embodiment of the present invention.

15 illustrates a block diagram of a communication device according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details.

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 this specification, a base station has a meaning as a terminal node of a network that directly communicates with a terminal. The specific operation described as performed by the base station in this document may be performed by an upper node of the base station in some cases. That is, it is obvious that various operations performed for communication with a terminal in a network composed of a plurality of network nodes including a base station may be performed by the base station or other network nodes other than the base station. A 'base station (BS)' may be replaced by terms such as a fixed station, a Node B, an evolved-NodeB (eNB), a base transceiver system (BTS), an access point (AP), and the like. . In addition, a 'terminal' may be fixed or mobile, and may include a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a subscriber station (SS), and an AMS ( Advanced Mobile Station (WT), Wireless Terminal (WT), Machine-Type Communication (MTC) Device, Machine-to-Machine (M2M) Device, Device-to-Device (D2D) Device, etc.

Hereinafter, downlink (DL) means communication from a base station to a terminal, and uplink (UL) means communication from a terminal to a base station. In downlink, a transmitter may be part of a base station, and a receiver may be part of a terminal. In uplink, a transmitter may be part of a terminal and a receiver may be part of a base station.

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.

The following techniques are 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 NOMA It can be used in various radio access systems such as non-orthogonal multiple access. CDMA may be implemented by 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 in a wireless technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, evolved UTRA (E-UTRA). UTRA is part of a universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) using E-UTRA, and employs OFDMA in downlink and SC-FDMA in uplink. LTE-A (advanced) is the evolution of 3GPP LTE.

Embodiments of the present invention may be supported by standard documents disclosed in at least one of the wireless access systems IEEE 802, 3GPP and 3GPP2. 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.

For clarity, the following description focuses on 3GPP LTE / LTE-A, but the technical features of the present invention are not limited thereto.

Terms that can be 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 consisting of an Evolved Packet Core (EPC), which is a packet switched core network based on Internet Protocol (IP), and an access network such as LTE and UTRAN. UMTS is an evolutionary network.

NodeB: base station of UMTS network. It is installed outdoors and its coverage is macro cell size.

eNodeB: base station of EPS network. It is installed outdoors and its coverage is macro cell size.

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

IMS (IP Multimedia Subsystem): A subsystem for providing multimedia services based on IP.

International Mobile Subscriber Identity (IMSI): An internationally uniquely assigned user identifier in a mobile communications network.

Machine Type Communication (MTC): Communication performed by a machine without human intervention. It may also be referred to as M2M (Machine to Machine) communication.

MTC terminal (MTC UE or MTC device or MTC device): a terminal (eg, vending machine, etc.) having a function of communicating via a mobile communication network (for example, communicating with an MTC server via a PLMN) and performing an MTC function; Meter reading, etc.).

MTC server: A server on a network that manages an MTC terminal. It may exist inside or outside the mobile communication network. It may have an interface that an MTC user can access. In addition, the MTC server may provide MTC related services to other servers (Services Capability Server (SCS)), or the MTC server may be an MTC application server.

(MTC) application: services (e.g., remote meter reading, volume movement tracking, weather sensors, etc.)

(MTC) application server: a server on a network where (MTC) applications run

MTC feature: A function of a network to support an MTC application. For example, MTC monitoring is a feature for preparing for loss of equipment in an MTC application such as a remote meter reading, and low mobility is a feature for an MTC application for an MTC terminal such as a vending machine.

MTC User: The MTC user uses a service provided by the MTC server.

MTC subscriber: An entity having a connection relationship with a network operator and providing a service to one or more MTC terminals.

MTC group: A group of MTC terminals that share at least one MTC feature and belongs to an MTC subscriber.

Services Capability Server (SCS): An entity for communicating with an MTC InterWorking Function (MTC-IWF) and an MTC terminal on a Home PLMN (HPLMN), which is connected to a 3GPP network. SCS provides the capability for use by one or more MTC applications.

External Identifier: An identifier used by an external entity (e.g., an SCS or application server) of a 3GPP network to point to (or identify) an MTC terminal (or a subscriber to which the MTC terminal belongs). Globally unique. The external identifier is composed of a domain identifier and a local identifier as follows.

Domain Identifier: An identifier for identifying a domain in a control term of a mobile communication network operator. One provider may use a domain identifier for each service to provide access to different services.

Local Identifier: An identifier used to infer or obtain an International Mobile Subscriber Identity (IMSI). Local identifiers must be unique within the application domain and are managed by the mobile telecommunications network operator.

RAN (Radio Access Network): a unit including a Node B, a Radio Network Controller (RNC), and an eNodeB controlling the Node B in a 3GPP network. It exists at the terminal end and provides 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.

RANAP (RAN Application Part): between the RAN and the node in charge of controlling the core network (ie, Mobility Management Entity (MME) / Serving General Packet Radio Service (GPRS) Supporting Node) / MSC (Mobile Switching Center) Interface.

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.

Non-Access Stratum (NAS): A functional layer for transmitting and receiving signaling and traffic messages between a terminal and a core network in a UMTS and EPS protocol stack. The main function is to support the mobility of the terminal and to support the session management procedure for establishing and maintaining an IP connection between the terminal and the PDN GW.

Service Capability Exposure Function (SCEF): An entity in the 3GPP architecture for service capability exposure that provides a means for securely exposing the services and capabilities provided by the 3GPP network interface.

Hereinafter, the present invention will be described based on the terms defined above.

본 발명이 적용될 수 있는 시스템 일반General system to which the present invention can be applied

The network structure diagram of FIG. 1 briefly reconstructs a structure of an EPS (Evolved Packet System) including an Evolved Packet Core (EPC).

Evolved Packet Core (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 improved data transfer capability.

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), the IP-based base station (for example, eNodeB (evolved Node B)), EPC, application domain (for example, IMS) It can be configured through. 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) (or S-GW), PDN GW (Packet Data Network Gateway) (or PGW or P-GW), A mobility management entity (MME), a Serving General Packet Radio Service (GPRS) Supporting Node (SGSN), and an enhanced Packet Data Gateway (ePDG) are shown.

The SGW 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 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. Also, untrusted networks such as 3GPP networks and non-3GPP networks (e.g., Interworking Wireless Local Area Networks (I-WLANs), trusted divisions such as Code Division Multiple Access (CDMA) networks or Wimax). It can serve as an anchor point for mobility management with the network.

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 for supporting access to a network connection, allocation of network resources, tracking, paging, roaming, handover, and the like. The MME controls the 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 includes 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. For example, 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, various reference points may exist according to the network structure.

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 relevant control and mobility resources 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 the PDN GW.

The E-UTRAN system is an evolution from the existing UTRAN system and may be, for example, a 3GPP LTE / LTE-A system. Communication networks are widely deployed to provide various communication services, such as voice (eg, Voice over Internet Protocol (VoIP)) over IMS and packet data.

2, an E-UMTS network includes an E-UTRAN, an EPC, and one or more UEs. The E-UTRAN consists of eNBs providing a control plane and a user plane protocol to the UE, and the eNBs are connected through an X2 interface.

X2 user plane interface (X2-U) is defined between eNBs. The X2-U interface provides non guaranteed delivery of user plane packet data units (PDUs). An X2 control plane interface (X2-CP) is defined between two neighboring eNBs. X2-CP performs functions such as context transfer between eNBs, control of user plane tunnel between source eNB and target eNB, delivery of handover related messages, and uplink load management.

The eNB is connected to the terminal through a wireless interface and is connected to an evolved packet core (EPC) through the S1 interface.

The S1 user plane interface (S1-U) is defined between the eNB and the serving gateway (S-GW). The S1 control plane interface (S1-MME) is defined between the eNB and the mobility management entity (MME). The S1 interface performs an evolved packet system (EPS) bearer service management function, a non-access stratum (NAS) signaling transport function, network sharing, and MME load balancing function. The S1 interface supports a many-to-many-relation between eNB and MME / S-GW.

MME provides NAS signaling security, access stratum (AS) security control, inter-CN inter-CN signaling to support mobility between 3GPP access networks, and performing and controlling paging retransmission. IDLE mode UE accessibility, tracking area identity (TAI) management (for children and active mode terminals), PDN GW and SGW selection, MME for handover with MME changes Public warning system (PWS), bearer management capabilities including optional, SGSN selection for handover to 2G or 3G 3GPP access networks, roaming, authentication, dedicated bearer establishment System (including Earthquake and Tsunami Warning System (ETWS) and Commercial Mobile Alert System (CMAS)) support for message transmission. Can.

Referring to FIG. 3, an eNB may select a gateway (eg, MME), route to the gateway during radio resource control (RRC) activation, scheduling of a broadcast channel (BCH), and the like. Dynamic resource allocation to the UE in transmission, uplink and downlink, and may perform the function of mobility control connection in the LTE_ACTIVE state. As mentioned above, within the EPC, the gateway is responsible for paging initiation, LTE_IDLE state management, ciphering of the user plane, System Architecture Evolution (SAE) bearer control, and NAS signaling encryption. It can perform the functions of ciphering and integrity protection.

FIG. 4 (a) shows the radio protocol structure for the control plane and FIG. 4 (b) shows the radio protocol structure for the user plane.

Referring to FIG. 4, the layers of the air interface protocol between the terminal and the E-UTRAN are based on the lower three layers of the open system interconnection (OSI) standard model known in the art of communication systems. It may be divided into a first layer L1, a second layer L2, and a third layer L3. The air interface protocol between the UE and the E-UTRAN consists of a physical layer, a data link layer, and a network layer horizontally, and vertically stacks a protocol stack for transmitting data information. (protocol stack) It is divided into a user plane and a control plane, which is a protocol stack for transmitting control signals.

The control plane refers to a path through which control messages used by the terminal and the network to manage a call are transmitted. The user plane refers to a path through which data generated at an application layer, for example, voice data or Internet packet data, is transmitted. Hereinafter, each layer of the control plane and the user plane of the radio protocol will be described.

A physical layer (PHY), which is a first layer (L1), provides an information transfer service to a higher layer by using a physical channel. The physical layer is connected to a medium access control (MAC) layer located at a higher level through a transport channel, and data is transmitted between the MAC layer and the physical layer through the transport channel. Transport channels are classified according to how and with what characteristics data is transmitted over the air interface. In addition, data is transmitted between different physical layers through a physical channel between a physical layer of a transmitter and a physical layer of a receiver. The physical layer is modulated by an orthogonal frequency division multiplexing (OFDM) scheme and utilizes time and frequency as radio resources.

There are several physical control channels used at the physical layer. A physical downlink control channel (PDCCH) is a resource allocation of a paging channel (PCH) and a downlink shared channel (DL-SCH) and uplink shared channel (UL-SCH) to the UE. : informs hybrid automatic repeat request (HARQ) information associated with an uplink shared channel (HARQ). In addition, the PDCCH may carry an UL grant that informs the UE of resource allocation of uplink transmission. The physical control format indicator channel (PDFICH) informs the UE of the number of OFDM symbols used for PDCCHs and is transmitted every subframe. A physical HARQ indicator channel (PHICH) carries a HARQ acknowledgment (ACK) / non-acknowledge (NACK) signal in response to uplink transmission. The physical uplink control channel (PUCCH) carries uplink control information such as HARQ ACK / NACK, downlink request and channel quality indicator (CQI) for downlink transmission. A physical uplink shared channel (PUSCH) carries a UL-SCH.

The MAC layer of the second layer (L2) provides a service to a radio link control (RLC) layer, which is a higher layer, through a logical channel. In addition, the MAC layer multiplexes / demultiplexes into a transport block provided as a physical channel on a transport channel of a MAC service data unit (SDU) belonging to the logical channel and mapping between the logical channel and the transport channel. Includes features

The RLC layer of the second layer (L2) supports reliable data transmission. Functions of the RLC layer include concatenation, segmentation, and reassembly of RLC SDUs. In order to guarantee the various quality of service (QoS) required by the radio bearer (RB), the RLC layer has a transparent mode (TM), an unacknowledged mode (UM) and an acknowledgment mode (AM). There are three modes of operation: acknowledge mode. AM RLC provides error correction through an automatic repeat request (ARQ). Meanwhile, when the MAC layer performs an RLC function, the RLC layer may be included as a functional block of the MAC layer.

The packet data convergence protocol (PDCP) layer of the second layer (L2) performs user data transmission, header compression, and ciphering functions in the user plane. Header compression is relatively large and large in order to allow efficient transmission of Internet protocol (IP) packets, such as IPv4 (internet protocol version 4) or IPv6 (internet protocol version 6), over a small bandwidth wireless interface. It means the function to reduce the IP packet header size that contains unnecessary control information. The function of the PDCP layer in the control plane includes the transfer of control plane data and encryption / integrity protection.

A radio resource control (RRC) layer located at the lowest part of the third layer 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 with each other through the RRC layer. The RRC layer controls the logical channel, transport channel and physical channel with respect to configuration, re-configuration and release of radio bearers. The radio bearer means a logical path provided by the second layer (L2) for data transmission between the terminal and the network. Establishing a radio bearer means defining characteristics of a radio protocol layer and a channel to provide a specific service, and setting each specific parameter and operation method. The radio bearer may be further divided into two signaling radio bearers (SRBs) and data radio bearers (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.

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

One cell constituting the base station is set to one of the bandwidth, such as 1.25, 2.5, 5, 10, 20Mhz to provide a downlink or uplink transmission service to multiple terminals. Different cells may be configured to provide different bandwidths.

A downlink transport channel for transmitting data from a network to a terminal includes a broadcast channel (BCH) for transmitting system information, a PCH for transmitting a paging message, and a DL-SCH for transmitting user traffic or control messages. There is this. Traffic or control messages of the downlink multicast or broadcast service may be transmitted through the DL-SCH or may be transmitted through a separate downlink multicast channel (MCH). Meanwhile, an uplink transport channel for transmitting data from a terminal to a network includes a random access channel (RACH) for transmitting an initial control message, and an UL-SCH (uplink shared) for transmitting user traffic or a control message. channel).

The logical channel is on top of the transport channel and is mapped to the transport channel. The logical channel may be divided into a control channel for transmitting control region information and a traffic channel for delivering user region information. The control channel includes a broadcast control channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a dedicated control channel (DCCH), multicast And a control channel (MCCH: multicast control channel). Traffic channels include a dedicated traffic channel (DTCH) and a multicast traffic channel (MTCH). PCCH is a downlink channel that carries paging information and is used when the network does not know the cell to which the UE belongs. CCCH is used by a UE that does not have an RRC connection with the network. A point-to-multipoint downlink channel used to convey multimedia broadcast and multicast service (MBMS) control information from an MCCH network to a UE. The DCCH is a point-to-point bi-directional channel used by a terminal having an RRC connection for transferring dedicated control information between the UE and the network. DTCH is a point-to-point channel dedicated to one terminal for transmitting user information that may exist in uplink and downlink. MTCH is a point-to-multipoint downlink channel for carrying traffic data from the network to the UE.

In the case of an uplink connection between a logical channel and a transport channel, the DCCH may be mapped to the UL-SCH, the DTCH may be mapped to the UL-SCH, and the CCCH may be mapped to the UL-SCH. Can be. In the case of a downlink connection between a logical channel and a transport channel, the BCCH may be mapped with the BCH or DL-SCH, the PCCH may be mapped with the PCH, and the DCCH may be mapped with the DL-SCH. The DTCH may be mapped with the DL-SCH, the MCCH may be mapped with the MCH, and the MTCH may be mapped with the MCH.

Referring to FIG. 5, a physical channel transmits signaling and data through a radio resource including one or more subcarriers in a frequency domain and one or more symbols in a time domain.

One subframe having a length of 1.0 ms is composed of a plurality of symbols. The specific symbol (s) of the subframe (eg, the first symbol of the subframe) can be used for the PDCCH. The PDCCH carries information about dynamically allocated resources (eg, a resource block, a modulation and coding scheme (MCS), etc.).

랜덤 액세스 절차(Random Access Procedure)Random Access Procedure

Hereinafter, a random access procedure provided by the LTE / LTE-A system will be described.

In the random access procedure, since the terminal does not have an RRC connection with the base station and performs initial access in the RRC idle state, the UE performs an RRC connection re-establishment procedure. Cases are performed.

In the LTE / LTE-A system, in the process of selecting a random access preamble (RACH preamble), a contention-based random access procedure in which the UE randomly selects and uses one preamble within a specific set And a non-contention based random access procedure using a random access preamble allocated by a base station only to a specific terminal.

(1) first message (Msg 1, message 1)

First, the UE randomly selects one random access preamble (RACH preamble) from a set of random access preambles indicated through system information or a handover command, and A physical RACH (PRACH) resource capable of transmitting a random access preamble is selected and transmitted.

The base station receiving the random access preamble from the terminal decodes the preamble and obtains an RA-RNTI. The RA-RNTI associated with the PRACH in which the random access preamble is transmitted is determined according to the time-frequency resource of the random access preamble transmitted by the corresponding UE.

(2) a second message (Msg 2, message 2)

The base station transmits a random access response addressed to the RA-RNTI obtained through the preamble on the first message to the terminal. The random access response includes a random access preamble identifier (RA preamble index / identifier), an uplink grant (UL grant) indicating an uplink radio resource, a temporary cell identifier (TC-RNTI), and a time synchronization value ( TAC: time alignment commands) may be included. The TAC is information indicating a time synchronization value that the base station sends to the terminal to maintain uplink time alignment. The terminal updates the uplink transmission timing by using the time synchronization value. When the terminal updates the time synchronization, a time alignment timer is started or restarted. The UL grant includes an uplink resource allocation and a transmit power command (TPC) used for transmission of a scheduling message (third message), which will be described later. TPC is used to determine the transmit power for the scheduled PUSCH.

After the UE transmits the random access preamble, the base station attempts to receive its random access response within the random access response window indicated by the system information or the handover command, and PRACH The PDCCH masked by the RA-RNTI corresponding to the PDCCH is detected, and the PDSCH indicated by the detected PDCCH is received. The random access response information may be transmitted in the form of a MAC packet data unit (MAC PDU), and the MAC PDU may be transmitted through a PDSCH.

If the terminal successfully receives a random access response having the same random access preamble identifier / identifier as the random access preamble transmitted to the base station, the monitoring stops the random access response. On the other hand, if the random access response message is not received until the random access response window ends, or if a valid random access response having the same random access preamble identifier as the random access preamble transmitted to the base station is not received, the random access response is received. Is considered to have failed, and then the UE may perform preamble retransmission.

(3) third message (Msg 3, message 3)

When the terminal receives a valid random access response to the terminal, it processes each of the information included in the random access response. That is, the terminal applies the TAC, and stores the TC-RNTI. In addition, by using the UL grant, the data stored in the buffer of the terminal or newly generated data is transmitted to the base station.

In case of initial access of the UE, an RRC connection request generated in the RRC layer and delivered through the CCCH may be included in the third message and transmitted. In the case of the RRC connection reestablishment procedure, the RRC layer is generated in the RRC layer and CCCH. The RRC connection reestablishment request delivered through the RRC connection reestablishment request may be included in the third message and transmitted. It may also include a NAS connection request message.

The third message should include the identifier of the terminal. There are two methods for including the identifier of the terminal. In the first method, if the UE has a valid cell identifier (C-RNTI) allocated in the corresponding cell before the random access procedure, the UE transmits its cell identifier through an uplink transmission signal corresponding to the UL grant. do. On the other hand, if a valid cell identifier has not been allocated before the random access procedure, the UE transmits its own unique identifier (eg, S-TMSI or random number). In general, the unique identifier is longer than the C-RNTI.

If the UE transmits data corresponding to the UL grant, it starts a timer for contention resolution (contention resolution timer).

(4) Fourth message (Msg 4, message 4)

When the base station receives the C-RNTI of the terminal through the third message from the terminal, the base station transmits a fourth message to the terminal using the received C-RNTI. On the other hand, when the unique identifier (ie, S-TMSI or random number) is received from the terminal through the third message, the fourth message is transmitted using the TC-RNTI allocated to the terminal in the random access response. Send to the terminal. For example, the fourth message may include an RRC connection setup message.

After transmitting the data including its identifier through the UL grant included in the random access response, the terminal waits for an instruction of the base station to resolve the collision. That is, it attempts to receive a PDCCH to receive a specific message. There are two methods for receiving the PDCCH. As mentioned above, when the third message transmitted in response to the UL grant is its C-RNTI, it attempts to receive the PDCCH using its C-RNTI, and the identifier is a unique identifier (that is, In the case of S-TMSI or a random number, it attempts to receive the PDCCH using the TC-RNTI included in the random access response. Then, in the former case, if the PDCCH is received through its C-RNTI before the conflict resolution timer expires, the terminal determines that the random access procedure has been normally performed, and terminates the random access procedure. In the latter case, if the PDCCH is received through the TC-RNTI before the conflict resolution timer expires, the data transmitted by the PDSCH indicated by the PDCCH is checked. If the unique identifier is included in the content of the data, the terminal determines that the random access procedure is normally performed, and terminates the random access procedure. The terminal acquires the C-RNTI through the fourth message, and then the terminal and the network transmit and receive a terminal-specific message using the C-RNTI.

Meanwhile, unlike the contention-based random access procedure illustrated in FIG. 6, the random access procedure is terminated by only transmitting the first message and transmitting the second message. However, before the terminal transmits the random access preamble to the base station as the first message, the terminal is allocated a random access preamble from the base station, and transmits the allocated random access preamble to the base station as a first message, and sends a random access response from the base station. The random access procedure is terminated by receiving.

V2XV2X (vehicle-to-vehicle/infrastructure/pedestrian) 통신(vehicle-to-vehicle / infrastructure / pedestrian) communication

The following describes a V2X communication related technology that provides the following service types. Three typical service types of the V2X communication are as follows.

Vehicle-to-vehicle (V2V): communication between vehicles

Vehicle-to-infrastructure (V2I): Communication between a vehicle and a roadside unit (RSU) which is implemented in an eNB or a stationary UE )

Vehicle-to-pedestrian (V2P): communication between a vehicle and a device carried by an individual (pedestrian, cyclist, driver or passenger))

V2XV2X 아키텍처 기반의 PC5 Architecture based PC5

In a wireless communication system, the V2X control function may be defined as a logical function used for network related tasks required for the V2X. In this case, the reference points newly defined to perform the V2X control function may be defined as follows.

V1: A reference point between a V2X application and a V2X application server.

V2: A reference point between the V2X application and the V2X control of the operator network. V2X applications are connected to V2X control functions belonging to multiple PLMNs.

V3: A reference point between the V2X capable UE and the V2X control function of the operator network.

V4: Reference point between the HSS and the V2X control of the operator network.

V5: Reference point between V2X applications.

LTE-Uu: a reference point between a V2X capable UE and an E-UTRAN.

PC5: Reference point between V2X supporting UEs for vehicle to vehicle (V2V), vehicle to infrastructure (V2I) and vehicle to pedestrians / motorcyclists / bicyclists (V2P) services.

This PC5 interface corresponds to Sidelink. Sidelink corresponds to a UE-to-UE interface for sidelink communication and sidelink discovery. Sidelink communication is an AS function that enables direct communication between a plurality of nearby UEs using E-UTRA technology but not passing through a network node.

ProSeProSe (Proximity Services) in EPS(Proximity Services) in EPS

In EPS, ProSe functionality consists of ProSe discovery (direct or EPC level) and ProSe direct communication (using E-UTRAN or WLAN directly).

ProSe discovery uses E-UTRAN (with or without E-UTRAN) or EPC to identify the ProSe supported UE is in proximity. ProSe direct communication enables communication path establishment between two or more ProSe supporting UEs in direct communication range. E-UTRAN or WLAN may be used as the ProSe direct communication path.

The Prose function may be used for public safety related purposes such as:

ProSe-enabled public safety UEs can establish a direct communication path between two or more ProSe supported public safety UEs, regardless of whether the ProSe supported public safety UEs are serviced by the E-UTRAN.

ProSe direct communication is also easy with the use of ProSe UE-to-Network relays, which act as a relay between the E-UTRAN and the UE.

In ProSe direct communication, PC5 interface is used, and ProSe Per-Packet Priority (PPPP) is used as a priority parameter. These PPPPs, in ProSe direct communication, are intra-UE transmissions (ie, protocol data units associated with different priorities at the same UE and waiting for transmissions) and inter-UE transmissions (ie, different priorities at different UEs). Associated with the rank and used for protocol data units waiting for transmission.

When the ProSe upper layer (ie, above PC5 access stratum) passes protocol data units for transmission to the PC5 access layer, the ProSe upper layer will provide PPPP within the range of eight possible values. Can be. PPPP is independent of Destination Layer-2 ID and can be applied to both one-to-one and one-to-many ProSe direct communications. This PPPP can be selected by the application server.

The PPPP value should be assigned to the PC5-S message. The UE may be configured with one PPPP value to use for transmitting the PC5-S message.

PPPP is neutral depending on whether the mode in which the UE accesses the medium, ie scheduled transmission mode (hereinafter 'mode 1') or autonomous transmission mode (hereinafter 'mode 2'), is used. Herein, mode 1 is a mode in which a UE receives PC5 resources allocated from an eNB and transmits data, and mode 2 is a mode in which a UE directly selects a specific PC5 resource among PC5 resources allocated from the eNB and transmits data.

The ProSe access layer uses PPPP associated with protocol data units received from higher layers to prioritize transmissions for other intra-UE transmissions and inter-UE transmissions.

Priority queues (both intra-UE and inter-UE) are expected to be serviced according to priority. That is, the UE services all packets related to PPPP N before serving packets related to PPPP N + 1 (ie, the lower the PPPP value, the higher the priority).

논리 채널 Logical channel 우선 순위Priority 지정(Logical channel prioritization) Logical channel prioritization

Hereinafter, a logical channel prioritization method for UL-SCH data transmission and a logical channel prioritization method for sidelink (SL) -SCH data transmission will be described.

1. Logical Channel Prioritization Method in UL-SCH Data Transmission

The logical channel prioritization procedure may be applied when a new transmission is performed.

The RRC controls scheduling of UL data by signaling for each logical channel: 'priority', where the increasing priority value indicates a lower priority level, and 'prioritisedBitRate', which sets the priority bit rate (PBR). ',' BucketSizeDuration 'to set bucket size duration (BSD). However, in NB (Narrow Band) -Internet of Things (IoT), steps corresponding to prioritisedBitRate, bucketSizeDuration, and logical channel prioritization procedure (that is, steps 1 and 2 described below) are not applied.

The MAC entity must maintain a variable Bj for each logical channel j. Bj is initialized to '0' when the associated logical channel is established, and PBR is increased by the product 'PBR × TTI duration' for each TTI of the priority bit rate of logical channel j. However, the value of Bj cannot exceed the bucket size, and if the value of Bj is larger than the bucket size of logical channel j, it should be set to the bucket size. The bucket size of a logical channel is equal to PBR × BSD, where PBR and BSD are set by higher layers.

When a MAC entity performs a new transmission, it should perform the following logical channel prioritization procedure:

The MAC entity must allocate resources to the logical channel through the steps described below:

Step 1: All logical channels with Bj> 0 are allocated resources in decreasing order of priority. If the PBR of a logical channel is set to infinity, the MAC entity must allocate resources for all data available for transmission over the logical channel before meeting the PBR of the lower priority logical channel (s).

Step 2: The MAC entity must reduce Bj by the total size of MAC SDUs serviced to logical channel j in step 1. In this case, the Bj value may be negative.

Step 3: If resources remain, all logical channels are provided in sequential order of decreasing priority (regardless of the value of Bj) until the corresponding logical channel or data for UL grant is exhausted. Logical channels with the same priority should be provided identically.

The UE must also follow the rules below during the above scheduling procedure.

If the entire RLC SDU (or partially transmitted SDU or retransmitted RLC PDU) enters the remaining resources of the associated MAC entity, the UE sends the corresponding RLC SDU (or partially transmitted SDU or retransmitted RLC PDU). Do not divide.

If the UE splits the RLC SDU from the logical channel, the size of the segment should be maximized to satisfy the grants of as many associated MAC entities as possible.

UE should maximize data transmission.

If the MAC entity has data available for transmission and is given a UL grant size greater than or equal to 4 bytes, then the MAC entity shall not transmit only the padding BSR and / or padding. Unless it is less than 7 bytes and an AMD PDU segment needs to be sent).

For transmission in a serving cell operating according to frame structure type 3, the MAC entity shall only consider logical channels for which laa-Allowed is configured.

The MAC entity shall not transmit data for the logical channel corresponding to the paused radio bearer.

If the MAC PDU contains only a MAC control element (MAC CE) for padding BSR or periodic BSR with zero MAC SDU, and there is no aperiodic CSI requested for this TTI, the MAC entity is assigned to the HARQ entity in the following cases: Do not create a MAC PDU for:

The MAC entity is configured with skipUplinkTxDynamic and the grant indicated to the HARQ entity is addressed with C-RNTI; or

When the MAC entity is configured with skipUplinkTxSPS and the grant indicated in the HARQ entity is a UL grant established;

In logical channel prioritization procedures, MAC entities should consider the following relative priorities in decreasing order:

MAC control element for C-RNTI or data from UL-Common Control Channel (CCCH);

MAC control element for Semi-Persistent Scheduling (SPS) verification;

MAC control element for BSR except for BSR included for padding;

MAC control element for PHR, extended PHR or dual connectivity PHR (Power Headroom Report);

MAC control element for Sidelink BSR (except Sidelink BSR included for padding);

Data from any logical channel except data from UL-CCCH;

A MAC control element for BSR included in the padding;

MAC control element for Sidelink BSR included for padding.

If a MAC entity is requested to transmit multiple MAC PDUs in one TTI, steps 1-3 and associated rules may be applied independently of each grant or to the sum of the capacities of the grants. Also, the order in which approvals are processed is a UE implementation issue. When a MAC entity is requested to transmit multiple MAC PDUs in one TTI, it is a UE implementation issue to determine which MAC PDU contains a MAC control element. If the UE is requested to generate MAC PDU (s) with two MAC entities in one TTI, this is determined based on the UE's implementation in the order in which authorizations are processed.

2. Logical Channel Prioritization Method in SL-SCH Data Transmission

The logical channel prioritization procedure is applied when a new transmission is performed.

Each Sidelink logical channel has a PPPP related priority as described above. Multiple Sidelink logical channels may have the same priority. The mapping between the priority and the Logical Channel ID (LC ID) may be a UE implementation issue.

The MAC entity performs the following logical channel prioritization procedures for each Sidelink Control Information (SCI) transmitted in the Sidelink Control (SC) cycle in Sidelink communications or for each SCI corresponding to a new transmission in V2X Sidelink communications: Should be.

1. The MAC Entity must allocate resources to the Sidelink logical channel in the following steps.

For SC periods and SC periods that overlap with this SC period, consider only Sidelink logical channels that were not previously selected to have data that can be transmitted in Sidelink communications.

Step 0: select a ProSe destination having the highest priority Sidelink logical channel among the Sidelink logical channels with data available for transmission;

For each MAC PDU associated with the SCI:

Step 1: Allocates resources to the sidelink logical channel having the highest priority among the sidelink logical channels belonging to the selected ProSe destination and having transmittable data.

Step 2: If resources remain, Sidelink logical channels belonging to the selected ProSe destination will be presented in descending order of priority until one of the Sidelink logical channels or data for the SL grant is first exhausted ( serve). Sidelink logical channels set to the same priority must be identically provisioned.

2. The UE must also follow the following rules during the above scheduling procedure.

The UE shall not split the RLC SDU (or partially transmitted SDU) if the entire SDU (or partially transmitted SDU) enters the remaining resources;

If the UE splits the RLC SDU from the Sidelink logical channel, the UE should maximize the size of the segment to fill the grant as much as possible;

UE should maximize data transmission.

If the MAC entity has data available for transmission and is given a Sidelink grant size of 10 bytes (for Sidelink communication) or 11 bytes (for V2X Sidelink communication), the UE shall not transmit only padding.

버퍼 상태 보고(Buffer Status Reporting; Buffer Status Reporting; BSRBSR ))

The buffer status reporting procedure is used by the serving eNB to provide information about the amount of data available for transmission in the UL buffer associated with the MAC entity. The RRC controls the BSR reporting by configuring three timers 'periodicBSR-Timer', 'retxBSR timer' and 'logicalChannelSR-ProhibitTimer' and selectively signaling 'logicalChannelGroup' which assigns a logical channel to the LCG.

For the buffer status reporting procedure, the MAC entity must consider all radio bearers that are not suspended and radio bearers that are suspended.

For NB-IoT, Long BSR is not supported and all logical channels belong to one LCG.

The buffer status report (BSR) is triggered when the following events occur:

UL data for a logical channel belonging to the LCG can be transmitted in the RLC entity or PDCP entity, and the data belongs to a logical channel having a higher priority than that of any logical channel so that the data can already be transmitted. Or BSR when there is no data available for transmission for all logical channels belonging to the LCG, is called "regular BSR".

If the UL resource is allocated and the number of padding bits is greater than or equal to the size of the buffer status report MAC control element and its subheader, the BSR may be referred to as a "padding BSR".

The BSR when the 'retxBSR-Timer' expires and the MAC entity has data available for transmission on logical channels belonging to the LCG is referred to hereinafter as "Regular BSR".

-BSR when 'periodicBSR-Timer' expires is referred to as 'Periodic BSR' below.

For Regular BSR:

When the BSR is triggered by enabling data transmission on a logical channel with 'logicalChannelSR-ProhibitTimer' set by the higher layer:

start or restart the 'logicalChannelSR-ProhibitTimer';

- etc:

-If 'logicalChannelSR-ProhibitTimer' is running, stop it.

For Regular and Periodic BSR:

If one or more LCGs have data available for transmission in the TTI where the BSR is sent: report Long BSR;

-Otherwise Report Short BSR.

For Padding BSR:

If the number of padding bits is greater than the size of the Short BSR and its subheaders, but less than the size of the Long BSR and its subheaders:

If one or more LCGs have valid data for transmission in the TTI where the BSR is sent: Report the Truncated BSR of the LCG with the highest priority logical channel with data valid for the transmission.

-Otherwise Report Short BSR.

Otherwise, if the number of padding bits is greater than or equal to the size of the Long BSR and its subheader, the Long BSR is reported.

If the buffer status reporting procedure determines that one or more BSRs are triggered and not canceled:

If the MAC entity has UL resources allocated for new transmission for this TTI:

Instruct the Multiplexing and Assembly procedure to create BSR MAC control element (s).

-Start or restart 'periodicBSR-Timer' unless all generated BSRs are Truncated BSRs.

-start or restart the 'retxBSR-Timer'.

If Regular BSR is triggered and 'logicalChannelSR-ProhibitTimer' is not running:

If no uplink acknowledgment is configured or regular BSR is not triggered as data is available for the logical channel with logical channel SR masking ('logicalChannelSR-Mask') set by the higher layer:

-Scheduling request should be triggered.

MAC PDUs must contain at most one MAC BSR control element even when multiple events trigger BSRs up to the time that the BSR can be transmitted, in which case the Regular BSR and Periodic BSR should take precedence over the padding BSR.

The MAC entity must restart the retxBSR-Timer upon indication of acknowledgment of transmission of new data for any UL-SCH.

If the UL grant of this TTI can accommodate all pending data available for transmission but is not sufficient to additionally accommodate the BSR MAC control element and its subheaders, then all triggered BSRs must be cancelled. All triggered BSRs must be canceled when the BSR is included in the MAC PDU for transmission.

The MAC entity must transmit at most one regular / periodic BSR in the TTI. When the MAC entity is requested to transmit a plurality of MAC PDUs in the TTI, the padding BSR may be included in any MAC PDU not including the regular / periodic BSR.

All BSRs sent in a TTI must always reflect the buffer status after all MAC PDUs have been built for this TTI. Each LCG shall report at most one buffer status value per TTI, which shall be reported in all BSRs reporting the buffer status for that LCG.

Padding BSR cannot cancel Regular / Periodic BSR triggered except NB-IoT. The padding BSR is triggered only for a specific MAC PDU and when this MAC PDU is constructed the trigger is cancelled.

SidelinkSidelink 버퍼 상태 보고(Buffer Status Reporting) Buffer Status Reporting

The sidelink buffer status reporting procedure is used to provide the serving eNB with information about the amount of sidelink data that can be transmitted in the Sidelink (SL) buffer associated with the MAC entity. RRC controls two BSR reporting for Sidelink by setting two timers 'periodic-BSR-TimerSL' and 'retx-BSR-TimerSL'. Each Sidelink logical channel belongs to a Proximity Service (ProSe) Destination. Each Sidelink logical channel is assigned to the LCG according to the mapping between the priority of the Sidelink logical channel and the LCG ID and priority provided by the upper layer in 'logicalChGroupInfoList'. LCG is defined for each ProSe Destination.

Sidelink Buffer Status Reporting (BSR) is triggered when one of the following events occurs:

If the MAC entity has a configured Sidelink-Radio Network Temporary Identifier (SL-RNTI):

Sidelinks with SL data for the sidelink logical channel of the ProSe Destination become available for transmission on the RLC entity or PDCP entity, and whose data is higher than the priority of the Sidelink logical channel belonging to any LCG belonging to the same Prose destination. Sidelink BSR, such as when the data belonging to a logical channel is already available for transmission or there is no data currently available for transmission on any Sidelink logical channel belonging to the same Prose destination may be referred to hereinafter as 'Regular Sidelink BSR'. ;

Uplink resources are allocated after the padding BSR is triggered and the number of padding bits is equal to or greater than the size of the Sidelink BSR MAC control element containing the buffer status for the ProSe destination and at least one LCG of its subheader. Sidelink BSR is called "Padding Sidelink BSR".

Sidelink BSR when 'retx-BSR-TimerSL' expires and the MAC entity has data available for transmission on any Sidelink logical channel is referred to hereinafter as "Regular Sidelink BSR".

Sidelink BSR when 'Periodic-BSR-TimerSL' has expired is referred to as 'Periodic Sidelink BSR'.

- etc:

The SL-RNTI is configured by higher layers, and the SL data is available for transmission at the RLC entity or PDCP entity, in which case the Sidelink BSR is referred to below as "Regular Sidelink BSR".

For Regular and periodic Sidelink BSR:

If the number of bits of the UL grant is greater than or equal to the sidelink BSR size, which includes the buffer status for all LCGs with data available for transmission and their subheaders, report the Sidelink BSR with buffer status for all LCGs with transmittable data; ;

Otherwise, report a Truncated Sidelink BSR containing the buffer status for as many LCGs as possible with data that can be transmitted, taking into account the number of bits of the reporting UL grant.

For Padding Sidelink BSR:

if the number of padding bits remaining after the padding BSR is triggered is equal to or greater than the size of the Sidelink BSR including the data available for transmission and the buffer status for all LCGs with that subheader Report a Sidelink BSR containing buffer status for all LCGs with;

If the buffer status reporting procedure determines that at least one Sidelink BSR was triggered and not canceled:

If the MAC entity has an uplink resource allocated for a new transmission for this TTI and the allocated uplink resource can accept the Sidelink BSR MAC control element and its subheader as a result of logical channel prioritization:

Instruct the multiplexing and assembly procedure to create a Sidelink BSR MAC control element.

Start or restart 'periodic-BSR-TimerSL' unless all Sidelink BSRs created are Truncated Sidelink BSRs.

start or restart 'retx-BSR-TimerSL';

If Regular Sidelink BSR is executed:

-If uplink authorization is not set:

Scheduling request should be triggered.

The MAC PDU must include one Sidelink BSR MAC control element even when several events trigger Sidelink BSR until the time to transmit the Sidelink BSR. In this case, the regular Sidelink BSR and the periodic Sidelink BSR take precedence over the padding Sidelink BSR.

The MAC entity must restart the 'retx-BSR-TimerSL' upon receiving the SL acknowledgement.

If the remaining SL entitlements that are valid during the sidelink control (SC) period can accommodate all pending data available for transmission in the sidelink communication, or the remaining set SL grant (s) valid is valid in the V2X (Vehx-to-Everything) sidelink communication. All triggered regular sidelink BSRs should be canceled if they can accommodate all pending data that can be transmitted. If the MAC entity does not have data available for transmission on any Sidelink logical channel, all triggered Sidelink BSRs shall be canceled. When Sidelink BSR (except Trunked Sidelink BSR) is included in the MAC PDU for transmission, all triggered Sidelink BSRs must be canceled. When the higher layer configures autonomous resource selection, all triggered Sidelink BSRs are canceled and 'retx-BSR-TimerSL' and 'periodic-BSR-TimerSL' must be stopped.

The MAC entity must transmit at most one regular / periodic sidelink BSR in the TTI. If a MAC entity is requested to transmit multiple MAC PDUs in a TTI, it may include a padding sidelink BSR in any MAC PDU that does not contain a regular / periodic sidelink BSR.

All Sidelink BSRs sent to a TTI always reflect the buffer status after all MAC PDUs have been established for that TTI. Each LCG shall report at most one buffer status value per TTI, which shall be reported to all sidelink BSRs reporting the buffer status of the LCG.

Padding Sidelink BSR cannot cancel a triggered Regular / Periodic Sidelink BSR. Padding Sidelink BSR is triggered only for a specific MAC PDU, and once this MAC PDU is built, the trigger is canceled.

BSRBSR MAC 제어 요소 MAC control element

FIG. 8 (a) shows the Short BSR and Truncated BSR MAC control elements, and FIG. 8 (b) shows the Long BSR MAC control elements.

The Buffer Status Report (BSR) MAC control element may consist of one of the following:

short BSR and Truncated BSR formats: one LCG identifier (ID) field and one corresponding buffer size field (Fig. 8 (a)); or

long BSR format: four buffer size fields corresponding to LCG ID # 0 to # 3 (FIG. 8 (b)).

The BSR format may be identified by a subheader of a MAC PDU having a Logical Channel Identifier (LCID).

LCG ID fields and buffer size may be defined as follows.

LCG ID: The LCG ID field identifies the group of logical channel (s) for which the buffer status is reported. This field is 2 bits long.

Buffer size: The buffer size field identifies the total amount of data available on all logical channels of the LCG after all MAC PDUs for the TTI have been built. The amount of data is expressed in number of bytes. It must include all data available for transmission in the RLC layer and PDCP layer. The size of the RLC and MAC headers is not taken into account in the buffer size calculation. This field is 6 bits long.

If 'extendedBSR-Sizes' is not configured, the buffer size field may take the value disclosed in Table 2. If 'extendedBSR-Sizes' is configured, the buffer size field may take the values disclosed in Table 3.

Table 2 shows the buffer size levels for the BSR.

Table 3 shows the extended buffer size levels for BSR.

SidelinkSidelink BSRBSR MAC 제어 요소 MAC control element

FIG. 9 (a) shows the Sidelink BSR and Truncated Sidelink BSR MAC control elements for even N, and FIG. 8 (b) shows the Sidelink BSR and Truncated Sidelink BSR MAC control elements for odd N. FIG.

Sidelink BSR and Truncated Sidelink BSR MAC control elements are composed of one target index field, one LCG ID field, and one buffer size field corresponding to each reporting target group.

The sidelink BSR MAC control element may be identified as a MAC PDU subheader with an LCID and may vary in size.

For each included group, the fields are defined as follows (Figs. 9 (a) and 9 (b):

Target Index: The Target Index field identifies the ProSe target. This field is 4 bits long. If the value is set to the index of the target reported in 'destinationInfoList', and multiple such lists are reported, the values may be sequentially indexed in the same order in all lists.

-LCG ID: The Logical Channel Group ID field identifies the group of logical channel (s) for which buffer status is reported. The length of the field is 2 bits.

Buffer size: The buffer size field indicates the total amount of data available on all logical channels of the LCG of the ProSe target after all MAC PDUs of the TTI are built. The amount of data can be expressed in number of bytes. The buffer size field shall contain all data available for transmission in the RLC layer and PDCP layer. The size of the RLC and MAC headers is not taken into account in the buffer size calculation. The length of the buffer size field is 6 bits. The values taken by the buffer size field are shown in Table 2.

R: Reserved bit and set to "0".

The buffer size of the LCG is included in descending order from the highest priority of the Sidelink logical channel belonging to the LCG regardless of the value of the destination index field.

When the UE operates in mode 1 (ie, scheduled resource allocation scheme) for allocating PC5 resources from the eNB, the UE may transmit the above-described (sidelink) BSR to the eNB according to LCG ID information previously received from the eNB.

Each Sidelink logical channel is assigned / mapped to a Logical Channel Group (LCG) based on its priority (ie PPPP). The mapping of LCG IDs and priorities can be provided by logicalChGroupInfoList included in SL-CommConfig. have. That is, when the 3GPP layer receives the data packet for PC5 from the application server, the 3GPP layer may map the PPPP value of the packet and the priority of the LC (ie, PPPP). In addition, when the BSR is transmitted, the UE maps and transmits an LCG ID for each destination as shown in FIG. 7, and the LCG ID is mapped with at least one PPPP by the eNB.

10 illustrates a case where LCG 1 and PPPP 1 to 2, LCG 2 and PPPP 3, LCG 3 and PPPP 4 to 7, LCG 4 and PPPP 8 are mapped to each other by an eNB. In this case, the UE may select the LCG according to the destination and specify the LCG ID of the selected LCG in the BSR and transmit it to the eNB. The eNB may determine the priority of the corresponding BSR through the LCG ID of the BSR received from the UE.

PC5 자원 할당/선택 방법How to Allocate / Select PC5 Resources

ProSe applications and V2X services can use the same PC5 interface. The PC5 radio resources that can be allocated for the two services by region may be the same or different. In the case where the PC5 radio resources for the two services are the same, it may be assumed that UE # 1 transmits a BSR for ProSe application data packet transmission and UE # 2 transmits a BSR for V2X service data packet transmission to the eNB. have. In this case, a problem may occur when the LCG IDs of the two BSRs received by the eNB are the same and there is not enough PC5 resources that can be allocated to both the UE # 1 and # 2. More specifically, since the eNB determines PC5 resource priority allocation based on the PPPP corresponding to the LCG ID, the eNB determines which service (i.e., which service is transmitted to which UE # 1 and # 2 has transmitted the BSRs with the same LCG ID specified). There is an ambiguity that it is not possible to decide whether to allocate PC5 resources preferentially). Furthermore, since the two BSRs received by the eNB do not specify which BSR for which service, there is an ambiguity that the eNB cannot determine which PC5 resource to preferentially allocate to the UE using which service.

Or, in another situation, if the UE uses the ProSe application and the V2X service at the same time, and the lower layer of the UE receives the packet with the PPPP from the application layer, it may be determined whether the packet is for the ProSe application or the V2X service. none.

In addition, the eNB can only grasp the priority information from the LCG ID included in the BSR received from the UE, and cannot determine the type of service used by the UE sending the BSR. As a result, the LCG ID of the BSR requesting the PC5 resource for the ProSe application is the LCG ID of the BSR requesting the PC5 resource for the V2X service, although the eNB lacking PC5 resources to allocate has a high priority for the V2X service. If it is higher than the priority of, the PC5 resources are preferentially allocated to the UE using the ProSe application, and there is a problem that efficient resource allocation is impossible.

In this specification, when the UE transmits a data packet that needs to use a PC5 interface / resource, a method for distinguishing whether the data packet is for a ProSe application or a V2X service is proposed. In addition, the eNB also determines whether the PC5 resource requested through the BSR is used for ProSe applications or V2X services, and also proposes a method for efficiently allocating PC5 resources to the UE based on the determination result.

In the present specification, a UE collectively refers to a vehicle and a user who can use a ProSe application and / or a V2X service as “UE”.

The scheme for efficiently allocating PC5 resources to the UE proposed in this specification consists of a combination of one or more of the operations proposed below.

Hereinafter, it is assumed that the UE operates in a scheduled resource allocation scheme ('mode 1' for ProSe direct communication) in order to receive PC5 resources, but is not limited thereto, and the eNB allocates PC5 resources to the UE. Applicable to the operation / method.

1. Operation of UE for PC5 Resource Allocation Request

1-1. The UE may provide 'service priority information' (e.g., information that a V2X service takes precedence over a ProSe application, information that a ProSe application takes precedence over a V2X service) Is the highest priority or information that the ProSE application is highest priority), and may transmit it to the MME through NAS signaling. The MME may deliver the corresponding information received from the UE to the eNB. Alternatively, the MME may obtain the service priority information directly from the UE, instead of receiving the service priority information, from the UE and transmit the service priority information to the eNB.

1-2. When the application layer of the UE sends down a data packet of a ProSe application or a V2X service using PC5 resources to a lower layer, the application layer may send down information on which service (hereinafter, 'service information'). For example, the application layer of the UE may set a flag (1 bit) for which service the data packet is (for example, '0' for a packet for a ProSe application, or 'for packet for a V2X service'). Set to 1 'to send it down to the lower layer. Through such service information, the lower layer of the UE can recognize the service type (ProSe application or V2X service) of the data packet received from the upper layer. Based on this, the lower layer of the UE may perform any one of the following operations.

After checking the service information indicating the service of the data packet received from the upper layer, the lower layer of the UE may perform one of the following operations.

When a lower layer of the UE receives a data packet for one application from the application layer (that is, a data packet for a ProSe application or a V2X service), the PPPP configured / mapped for the corresponding data packet is It is possible to obtain an LCG ID in which the same PPPP is set / mapped. In this case, the lower layer of the UE generates a BSR for the corresponding data packet, and transmits to the eNB including / specified the LCG ID and service type (ProSe application or V2X service) of the data packet obtained before the generated BSR. Can be.

When receiving data packets for ProSe application and V2X service from the application layer (or higher layer) at the same time, the lower layer of the UE has LCG with the same PPPP set / mapped as the PPPP set / mapped for each data packet. ID can be obtained. In addition, the lower layer of the UE generates at least one BSR for the corresponding data packets, and includes the LCG ID obtained before the generated at least one BSR and the type of service of each data packet (ProSe application or V2X service). Send it to the eNB. In this case, BSRs of two data packets for different services may be generated as one BSR or may be generated as separate BSRs and transmitted to the eNB.

In the present embodiment, the operation of the application / upper layer and the lower layer of the UE may be collectively expressed as the operation of 'UE'.

2. Operation of eNB for Allocating PC5 Resources

The eNB receives a request for PC5 resource allocation for ProSe application and / or V2X service data packet transmission from the UE through the BSR, but there may be a shortage of PC5 resources that can be allocated to the UE in the service area of the eNB. In this case, the eNB may perform at least one of the following operations based on the service information specified in the BSR received from the UE (or indicated by the BSR) and the LCG ID.

(1) when BSRs requesting PC5 resources for different services from different UEs

When receiving BSRs requesting PC5 resources for different services from different UEs, the eNB may allocate PC5 resources based on the LCG ID of each BSR. For example, when the eNB receives a first BSR requesting PC5 resource for ProSe application from UE # 1, and a second BSR requesting PC5 resource for V2X service from UE # 2, the first and second BSRs are received. By comparing the LCG IDs of the second BSR, PC5 resources may be allocated in the order of high priority.

However, if the eNB has the same LCG ID of the BSR received from different UEs, the eNB may preferentially provide the PC5 resource based on the received BSR's service information, network operator's policy and / or local policy, etc. Can be selected.

For example, if the V2X service has a higher priority than the ProSe application in the service area of the eNB according to the policy of the network operator / eNB, the eNB gives priority to the PC5 resource to the UE # 2 requesting the PC5 resource for the V2X service. Can be assigned. As such, in a region where the V2X service has a higher priority than the Prose application according to the policy of the network operator / eNB, the eNB may determine that the LCG ID of the BSR for the V2X service has a lower priority than the LCG ID of the Prose application. You can preferentially allocate PC5 resources for V2X services. In other words, in a service area where priority is set for a particular service, the eNB preferentially prioritizes PC5 resources for a specific service that is set priority in the service area regardless of the priority of the LCG ID of the received BSR. Can be assigned.

(2) When a BSR for simultaneously requesting PC5 resources for ProSe application and V2X service is received from one UE

When the eNB simultaneously receives BSRs requesting PC5 resources for ProSe application and V2X service from one UE, the PCG resources may be allocated to the high priority service by comparing the LCG IDs of the two BSRs with each other. have.

However, if the LCG IDs of the two BSRs are the same, the eNB may select a service to preferentially provide the PC5 resource based on the received service information of the BSR, the policy and / or local policy of the network operator. When allocating PC5 resources, the eNB may provide the UE with information about a service to which the corresponding PC5 resources are allocated.

Alternatively, when the eNB receives service priority information on the service priority of the UE from the MME, the eNB may allocate PC5 resources based on the corresponding information. For example, when the eNB receives service priority information indicating that the V2X service takes precedence over the ProSe application, the eNB allocates PC5 resources for the V2X service to the ProSe application in priority, and the allocated PC5 resource is a resource for the V2X service. May inform the UE.

3. Operation of UE using PC5 resources

UE uses PC5 resources (e.g., radio frequency / time resources used to perform PC5 operations) allocated from eNB to PC5 operations (e.g., V2X messages over PC5 interfaces / resources, ProSe application data Packet and / or V2X service data packet transmission).

If the UE requests the PC5 resources for the ProSe application and the V2X service at the same time, the UE may receive service information indicating which service the PC5 resource allocated to the UE is from the eNB. In this case, the UE may use it to transmit a data packet / traffic for a service indicated by the service information receiving the allocated PC5 resource.

11 is a flowchart illustrating a PC5 resource allocation method according to an embodiment of the present invention. In the above flowchart, the above-described embodiments may be applied in the same or similar manner, and redundant descriptions thereof will be omitted.

First, the UE may transmit the first Sidelink BSR for the amount of first Sidelink data and the second Sidelink BSR for the amount of second Sidelink data to the eNB (S1110). Here, the first sidelink BSR indicates a service type of the first sidelink data, and the second sidelink BSR indicates a service type of the second sidelink data. The first and second sidelink BSRs may be configured with one same Sidelink BSR or may be configured with different sidelink BSRs different from each other. In this case, the service type of the first or second sidelink data may correspond to a ProSe (Proximity Service) or V2X service.

Next, the UE may be allocated PC5 resources for the first and / or second Sidelink data transmission from the eNB based on the LCG IDs included in the first and second Sidelink BSRs, respectively (S1120). In this case, when the LCG IDs of the first and second Sidelink BSRs are different, the PC5 resource may be preferentially allocated for sidelink data transmission corresponding to the Sidelink BSR including the LCG ID having a high priority. Alternatively, when the LCG IDs of the first and second Sidelnk BSRs are the same, the PC5 resource may be preferentially allocated for the first or second Sidelink data transmission based on the service type.

The PC5 resource represents a radio resource allocated for Sidelink data transmission through the PC5 interface, and the PC5 interface may correspond to a UE-UE interface for sidelink communication and sidelink discovery.

The LCG ID may be an identifier for identifying a group of logical channels whose buffer status is reported through the first or second Sidelink BSR. This LCG ID is mapped to at least one PPPP, and the PPPP may correspond to a priority parameter used to indicate the priority of the protocol data unit including the first or second sidelink data. The LCG ID may be mapped to an ID of a Proseimity Service (Prose) destination which is a transmission destination of the first or second sidelink data.

Although not shown in the flowchart, the UE may further receive service type information indicating which type of service the PC5 resource allocated from the eNB is. Furthermore, the UE may transmit sidelink data of a service type indicated through service type information using the allocated PC5 resource.

In the above, the method for efficiently allocating PC5 resources to the UE operating in mode 1 has been described. Hereinafter, a method for efficiently selecting a PC5 resource by a UE operating in mode 2 (ie, a UE autonomous resource selection / allocation method) will be described. Hereinafter, the 'transmission resource pool' may be referred to as 'PC5 resource pool' or 'source pool'.

When the UE operates in mode 2 to allocate PC5 resources from the eNB, the UE may receive transmission resource pool information from the eNB through system information block 18 (SIB) or select transmission resources through 'SL-preconfiguration' information. . There are a maximum of eight transmission pools, as shown in Figure 12 (a), each pool is mapped to one or more PPPPs.

The UE may select a transmission resource in the following manner based on this transmission pool.

The UE may select at least one resource from resource pools by itself and perform transmission format selection for transmitting Sidelink control information and data.

There may be up to eight transport pools pre-configured for out of coverage operations or provided by RRC signaling for in-coverage operations. Each pool can be one or more PPPP connections / mapped. For transmission of the MAC PDU, the UE may select a transmission pool with the same PPPP as the PPPP of the logical channel with the highest PPPP among the logical channels identified in the MAC PDU. Which one of a plurality of pools a UE has with the same PPPP may correspond to an implementation issue of the UE. The sidelink control pool and sidelink data pool may be mapped / associated one to one.

If either resource pool is selected, the selected pool may be valid for the entire sidelink control period. After the sidelink control period ends, the UE may perform resource pool selection again.

12 (b) illustrates the pull selection operation of such a UE.

The UE may select a transmission resource pool to transmit the data packet based on the PPPP. In this case, information about a transmission resource pool that can be selected by the UE may be received from the eNB through SIB 18, and the transmission resource pool information may include mapping information between the transmission pool and the PPPP.

For example, it may be assumed that the LCID of the data packet to be transmitted by the UE is '1'. Referring to FIG. 12 (b), LCID 1 is associated / mapped with PPPP 1 and resource pool 2 with PPPP 1, respectively. In this case, the UE may select resource pool 2 having the same PPPP 1 as the LCID (or associated / mapped with the same PPPP), and may transmit a data packet using radio resources provided by the selected resource pool 2.

That is, the UE may select a resource pool having the same PPPP as the LCID of the data packet to be transmitted and transmit the data packet through the corresponding resource pool.

As described above, the ProSe application and the V2X service may use PC5 resources when transmitting data packets. The eNB shares PC5 resources with the UE via SIB18.

It may be assumed that data packets for two services are simultaneously received in a 3GPP layer of a UE in which both services (ProSe application and V2X service) are available. In this case, as illustrated in FIG. 12B, the UE may select a transmission pool based on LCIDs (or PPPPs of LCIDs) of two data packets.

However, if the LCIDs of the data packets for both services (or PPPP of LCID) are the same, the resource pool the UE can choose (ie, a resource pool with the same LCID (or PPPP of LCID) as the data packets to send) If only one exists, there may be ambiguity about which service the UE should preferentially use the resource pool for. Or, if the PC5 resource pool can support only one service, there may be a problem that the UE does not know which service the corresponding PC5 resource pool supports.

Therefore, in the present specification, when the application layer of the UE sends down a data packet that needs to use a PC5 interface / resource to a lower layer, it proposes a method of dividing down whether the data packet is for a ProSe application or a V2X service. do. In addition, when the selectable PC5 resource pool is insufficient, the present invention proposes a method for efficiently determining / selecting a service to preferentially use the remaining PC5 resource pool of the UE.

The scheme for efficiently selecting a PC5 resource pool for the UE proposed in this specification consists of a combination of one or more of the operations proposed below.

1.Operation of UE Selecting PC5 Resource Pool

When the application layer of the UE sends down a data packet of a ProSe application or a V2X service using PC5 resources to a lower layer, the application layer may send down information on which service (hereinafter, 'service information'). For example, the application layer of the UE may set a flag (1 bit) for which service the data packet is (for example, '0' for a packet for a ProSe application, or 'for packet for a V2X service'). Set to 1 'to send it down to the lower layer. Through such service information, the lower layer of the UE can recognize the service type (ProSe application or V2X service) of the data packet received from the upper layer.

When the lower layer of the UE simultaneously receives a V2X service data packet and a ProSe application data packet from the application layer, the LCID (or PPPP of the LCID) of each data packet is compared with the transmission resource pool of the SIB18, so that each LCID (or LCID) Each data packet can be transmitted using a transmission resource pool that matches the PPPP).

However, if the PC5 resource pool is insufficient to transmit both data packets, the UE may perform at least one of the following operations.

1-1. If the LC ID (or PPPP of LC ID) of the two data packets are different: The lower layer of the UE compares the PPPP of the LCID of the two data packets and prioritizes the remaining transmission resource pool for the high priority data packet of the PPPP. Can be selected / used.

1-2. If the LC ID (or PPPP of the LC ID) of the two data packets is different (for example, there is only one PC5 transmission resource pool to transmit the two data packets): The lower layer of the UE If the PPPP is different, at least one of the following operations may be performed.

-Method instructed by eNB: '2. According to the operation of the eNB (PC5 resource indication) ", the UE may be instructed through SIB18 information about a service (which may be referred to as" service priority information ") that may preferentially use each resource pool from the eNB. In this case, the UE may preferentially select a data packet to transmit based on the service type of the data packets to be transmitted. More specifically, the UE may select the same data packet as the data packet to be preferentially transmitted as the service type set / specified for the available / remaining transmission resource pool.

-Method selected by the UE according to a predefined setting: The type of service to be transmitted can be preferentially selected according to provisioning information preset in the UE. For example, if the UE configuration specifies / set that the V2X service takes precedence over the ProSe application, the UE may use the selected resource pool for V2X service data packet transmission. This setting may be preset in the UE or obtained from the network (ProSe function and / or V2X control function).

2. Operation of the eNB (PC5 resource pool indication)

In addition to the pool ID of the PC5 resource and the PPPP mapped / mapped thereto, the SIB18 broadcast by the eNB may indicate / specify types of services that can use the PC5 resource pool. For example, SIB18 contains information (eg {Pool 1: PPPP 1: V2X service}) indicating that only V2X services with PPPP 1 (or V2X service data packets) can use Pool 1. Which service the resource pool will be used for may be determined based on the network operator's policy, local policy, and the like.

Meanwhile, in the present specification, an example of selectively transmitting a data packet for one service using one selected PC5 resource pool is not limited thereto, and a plurality of services may be used using one selected PC5 resource pool. Data packets may be sent together.

In addition, when the PC5 resource pool for transmitting the data packet is insufficient, the eNB may provide an exceptional PC5 resource pool to the UE.

13 is a flowchart illustrating a PC5 resource pool selection method of a UE according to an embodiment of the present invention. In the above flowchart, the above-described embodiments may be applied in the same or similar manner, and redundant descriptions thereof will be omitted.

First, the UE may receive PC5 resource pool information about at least one PPPP mapped to each of the plurality of PC5 resource pools and the plurality of PC5 resource pools (S1310). Such PC5 resource pool information may be signaled via SIB18 and transmitted from the eNB.

Next, the UE may generate a first MAC PDU for the first service and a second MAC PDU for the second service, respectively (S1320).

Next, PPPPs of a logical channel having the highest PPPP among logical channels identified in the first and second MAC PDUs may be obtained, respectively (S1330). Here, the logical channel having the highest PPPP means a PPPP having a high priority and may refer to a PPPP having a highest value or a PPPP having a lowest value. In addition, PPPP may be a priority parameter used to indicate the priority of the first and second MAC PDUs.

Next, the UE may select at least one PC5 resource pool mapped to the highest PPPPs acquired among the plurality of PC5 resource pools (S1340). In this case, as described above, since a plurality of PPPPs may be mapped to one PC5 resource pool, a case in which one same PC5 resource pool is selected as the PC5 resource pool mapped to the highest PPPPs obtained in step S1330 may occur. Can be. In this case, the UE may select / determine a MAC PDU to transmit using one PC5 resource pool selected based on the PPPP of the first and second MAC PDUs.

In more detail, the UE may determine whether the PPPPs of the first and second MAC PDUs are the same (S1350).

If the PPPPs of the first and second MAC PDUs are the same, the first or second MAC PDU may be selected based on the service type, and the selected MAC PDU may be transmitted through the selected PC5 resource pool (S1360). When selecting a first or second MAC PDU based on a service type, the UE may select the first or second MAC PDU based on service priority information regarding a service type to be preferentially selected. In this case, the service priority information may be previously set in the UE, or may be signaled through the SIB18 and received from the eNB. The service type may correspond to ProSe and V2X services.

On the contrary, when the PPPPs of the first and second MAC PDUs are different, the UE may select a MAC PDU having a higher PPPP among the first and second MAC PDUs and transmit it through the selected one PC5 resource pool (S1370). .

One PC5 resource pool selected in S1360 and / or S1370 may be used as a valid PC5 resource pool for a preset period.

본 발명이 적용될 수 있는 장치 일반General apparatus to which the present invention can be applied

Referring to FIG. 14, a wireless communication system includes a network node 1410 and a plurality of terminals (UEs) 1420.

The network node 1410 includes a processor 1411, a memory 1412, and a communication module 1413. The processor 1411 implements the functions, processes, and / or methods proposed in FIGS. 1 to 13. Layers of the wired / wireless interface protocol may be implemented by the processor 1411. The memory 1412 is connected to the processor 1411 and stores various information for driving the processor 1411. The communication module 1413 is connected to the processor 1411 to transmit and / or receive wired / wireless signals. As an example of the network node 1410, a base station, an MME, an HSS, an SGW, a PGW, an SCEF, or an SCS / AS may correspond thereto. In particular, when the network node 1410 is a base station, the communication module 1413 may include a radio frequency unit (RF) unit for transmitting / receiving a radio signal.

The terminal 1420 includes a processor 1421, a memory 1422, and a communication module (or RF unit) 1423. The processor 1421 implements the functions, processes, and / or methods proposed in FIGS. 1 to 13. Layers of the air interface protocol may be implemented by the processor 1421. The memory 1422 is connected to the processor 1421 and stores various information for driving the processor 1421. The communication module 1423 is connected with the processor 1421 to transmit and / or receive a radio signal.

The

memories

1412 and 1422 may be inside or outside the

processors

1411 and 1421, and may be connected to the

processors

1411 and 1421 through various well-known means. In addition, the network node 1410 (if the base station) and / or the terminal 1420 may have a single antenna (multiple antenna) or multiple antenna (multiple antenna).

In particular, FIG. 15 illustrates the terminal of FIG. 14 in more detail.

Referring to FIG. 15, a terminal may include a processor (or a digital signal processor (DSP) 1510, an RF module (or an RF unit) 1535, and a power management module 1505). ), Antenna 1540, battery 1555, display 1515, keypad 1520, memory 1530, SIM card Subscriber Identification Module card) 1525 (this configuration is optional), speaker 1545, and microphone 1550. The terminal may also include a single antenna or multiple antennas. Can be.

The processor 1510 implements the functions, processes, and / or methods proposed in FIGS. 1 to 14. The layer of the air interface protocol may be implemented by the processor 1510.

The memory 1530 is connected to the processor 1510 and stores information related to the operation of the processor 1510. The memory 1530 may be inside or outside the processor 1510 and may be connected to the processor 1510 by various well-known means.

A user enters command information, such as a telephone number, for example by pressing (or touching) a button on keypad 1520 or by voice activation using microphone 1550. The processor 1510 receives the command information, processes the telephone number, and performs a proper function. Operational data may be extracted from the SIM card 1525 or the memory 1530. In addition, the processor 1510 may display command information or driving information on the display 1515 for the user to recognize and for convenience.

The RF module 1535 is connected to the processor 1510 to transmit and / or receive an RF signal. The processor 1510 transmits command information to the RF module 1535 to transmit a radio signal constituting voice communication data, for example, to initiate communication. The RF module 1535 is composed of a receiver and a transmitter for receiving and transmitting a radio signal. The antenna 1540 functions to transmit and receive wireless signals. Upon receiving the wireless signal, the RF module 1535 may forward the signal and convert the signal to baseband for processing by the processor 1510. The processed signal may be converted into audible or readable information output through the speaker 1545.

The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature is to be considered optional unless stated otherwise. Each component or feature may be embodied in a form that is not combined with other components or features. It is also possible to combine some of the components and / or features to form an embodiment of the 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. It is obvious that the claims may be combined to form an embodiment by combining claims that do not have an explicit citation relationship in the claims or as new claims by post-application correction.

Embodiments according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of a hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), FPGAs ( field programmable gate arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc. that performs the functions or operations described above. The software code may be stored in memory and driven by the processor. The memory may be located inside or outside the processor, and may exchange data with the processor by various known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential features of the present invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

Although the present specification has been described with reference to the example applied to the 3GPP LTE / LTE-A system, it is possible to apply to various wireless communication systems in addition to the 3GPP LTE / LTE-A system.

Claims

In the method for a user equipment (UE) in a wireless communication system is allocated PC5 resources from an evolved-NodeB (eNB)

Transmitting a first Sidelink Buffer Status Report (BSR) for the amount of first Sidelink data that can be transmitted in a sidelink buffer and a second Sidelink BSR for the amount of second Sidelink data to the eNB; as,

The first Sidelink BSR indicates a service type of the first Sidelink data, and the second Sidelink BSR indicates a service type of the second Sidelink data, respectively.

Receiving, from the eNB, a PC5 resource for transmitting the first and / or second Sidelink data based on a Logical Channel Group (LCG) identifier (LCG) included in first and second Sidelink BSRs, respectively; Including,

The PC5 resource,

When the LCG IDs of the first and second Sidelink BSRs are different, the first and second Sidelink BSRs are preferentially allocated for Sidelink data transmission corresponding to the Sidelink BSR including the LCG ID having a high priority.

If the LCG IDs of the first and second Sidelnk BSRs are the same, the PC5 resource allocation method is preferentially allocated for the first or second Sidelink data transmission based on the service type.
The method of claim 1,

The PC5 resource represents a radio resource allocated for Sidelink data transmission through a PC5 interface.

The PC5 interface corresponds to the interface of the UE to the UE for sidelink communication and sidelink discovery.
The method of claim 2,

The first and second Sidelink BSR is configured with one same Sidelink BSR or different separate Sidelink BSR, method of allocating PC5 resources.
The method of claim 2,

The LCG ID is an identifier for identifying a group of logical channels whose buffer status is reported via the first or second Sidelink BSR.
The method of claim 4, wherein

The LCG ID is mapped to at least one Proximity Service (ProSe) per Packet Priority (PPPP),

Wherein the PPPP is a priority parameter used to indicate a priority of a protocol data unit including the first or second Sidelink data.
The method of claim 5, wherein

The LCG ID is mapped to an ID of a Proximity Service (Prose) destination that is a transmission destination of the first or second Sidelink data.
The method of claim 2,

If the LCG IDs of the first and second Sidelnk BSR are the same,

Receiving service type information indicating which service type the allocated PC5 resource is from the eNB; And

Transmitting sidelink data of a service type indicated through the service type information by using the allocated PC5 resource; Further comprising, the method of allocating PC5 resources.
The method of claim 7, wherein

The service type corresponds to a ProSe (Proximity Service) or V2X service.
In a user equipment (UE) allocated PC5 resources from an evolved-NodeB (eNB) in a wireless communication system,

A communication module for transmitting and receiving a signal; And

A processor controlling the communication module; Including,

The processor,

Transmitting a first Sidelink Buffer Status Report (BSR) for the amount of first Sidelink data that can be transmitted in a sidelink buffer and a second Sidelink BSR for the amount of second Sidelink data to the eNB,

The first Sidelink BSR indicates a service type of the first Sidelink data, and the second Sidelink BSR indicates a service type of the second Sidelink data, respectively.

PC5 resources for the first and / or second Sidelink data transmission are allocated from the eNB based on a Logical Channel Group (LCG) ID included in each of the first and second Sidelink BSRs,

The PC5 resource,

When the LCG IDs of the first and second Sidelink BSRs are different, the first and second Sidelink BSRs are preferentially allocated for Sidelink data transmission corresponding to the Sidelink BSR including the LCG ID having a high priority.

If the LCG IDs of the first and second Sidelnk BSR are the same, the UE is preferentially allocated for the first or second Sidelink data transmission based on the service type.
The method of claim 9,

The PC5 resource represents a radio resource allocated for Sidelink data transmission through a PC5 interface.

The PC5 interface corresponds to a UE to UE interface for sidelink communication and sidelink discovery.
The method of claim 10,

The LCG ID is an identifier identifying a group of logical channels for which a buffer status is reported via the first or second Sidelink BSR.
The method of claim 11,

The LCG ID is mapped to at least one Proximity Service (ProSe) per Packet Priority (PPPP),

The PPPP is a priority parameter used to indicate a priority of a protocol data unit including the first or second Sidelink data.
The method of claim 12,

The LCG ID is mapped to an ID of a Proximity Service (Prose) destination that is a transmission destination of the first or second Sidelink data.
The method of claim 10,

The processor,

Receiving service type information indicating which service type the allocated PC5 resource is from the eNB;

And transmitting Sidelink data of a service type indicated through the service type information by using the allocated PC5 resource.
The method of claim 14,

The service type corresponds to a ProSe (Proximity Service) or V2X service.