Patent Publication Number: US-11038638-B2

Title: Dual connectivity support for V2X communication

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Pursuant to 35 U.S.C. § 119 (e), this application claims the benefit of Korean Patent Application No. 10-2018-0127814, filed on Oct. 24, 2018, the contents of which are all hereby incorporated by reference herein in their entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to dual connectivity support for vehicle-to-everything (V2X) communication. 
     BACKGROUND 
     3rd generation partnership project (3GPP) long-term evolution (LTE) is a technology for enabling high-speed packet communications. Many schemes have been proposed for the LTE objective including those that aim to reduce user and provider costs, improve service quality, and expand and improve coverage and system capacity. The 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of a frequency band, a simple structure, an open interface, and adequate power consumption of a terminal as an upper-level requirement. 
     Work has started in international telecommunication union (ITU) and 3GPP to develop requirements and specifications for new radio (NR) systems. 3GPP has to identify and develop the technology components needed for successfully standardizing the new RAT timely satisfying both the urgent market needs, and the more long-term requirements set forth by the ITU radio communication sector (ITU-R) international mobile telecommunications (IMT)-2020 process. Further, the NR should be able to use any spectrum band ranging at least up to 100 GHz that may be made available for wireless communications even in a more distant future. 
     The NR targets a single technical framework addressing all usage scenarios, requirements and deployment scenarios including enhanced mobile broadband (eMBB), massive machine-type-communications (mMTC), ultra-reliable and low latency communications (URLLC), etc. The NR shall be inherently forward compatible. 
     Vehicle-to-everything (V2X) communication is the passing of information from a vehicle to any entity that may affect the vehicle, and vice versa. It is a vehicular communication system that incorporates other more specific types of communication as vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), vehicle-to-vehicle (V2V), vehicle-to-pedestrian (V2P), vehicle-to-device (V2D) and vehicle-to-grid (V2G). 
     SUMMARY 
     The present disclosure discusses sidelink resource allocation problem in case of dual connectivity so that the advanced V2X services can be realized in 5G NR. 
     In an aspect, a method for a master node (MN) belonging to a first radio access technology (RAT) in a wireless communication system is provided. The method includes receiving authorization information on a second RAT for a wireless device from a core network node, and transmitting a request for a radio resource of the second RAT to a secondary node (SN) belonging to the second RAT. The request includes the authorization information on the second RAT for the wireless device. The method further includes receiving information on the radio resource from the SN, and transmitting a message to the wireless device based on the information on the radio resource. 
     In another aspect, a method for a secondary node (SN) belonging to a second radio access technology (RAT) in a wireless communication system is provided. The method includes receiving a request for a radio resource of the second RAT from a master node (MN) belonging to a first RAT. The request includes authorization information on the second RAT for a wireless device. The method further includes determining the radio resource based on the authorization information and a resource pool, and transmitting information on the radio resource to the MN. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows examples of 5G usage scenarios to which the technical features of the present disclosure can be applied. 
         FIG. 2  shows an example of a wireless communication system to which the technical features of the present disclosure can be applied. 
         FIG. 3  shows an example of a wireless communication system to which the technical features of the present disclosure can be applied. 
         FIG. 4  shows another example of a wireless communication system to which the technical features of the present disclosure can be applied. 
         FIG. 5  shows a block diagram of a user plane protocol stack to which the technical features of the present disclosure can be applied. 
         FIG. 6  shows a block diagram of a control plane protocol stack to which the technical features of the present disclosure can be applied. 
         FIG. 7  shows an example of resource allocation for sidelink communication according to an embodiment of the present disclosure. 
         FIG. 8  shows another example of resource allocation for sidelink communication according to an embodiment of the present disclosure. 
         FIG. 9  shows another example of resource allocation for sidelink communication according to an embodiment of the present disclosure. 
         FIG. 10  shows another example of resource allocation for sidelink communication according to an embodiment of the present disclosure. 
         FIG. 11  shows another example of resource allocation for sidelink communication according to an embodiment of the present disclosure. 
         FIG. 12  shows another example of resource allocation for sidelink communication according to an embodiment of the present disclosure. 
         FIG. 13  shows an example of a method for an MN belonging to a first RAT according to an embodiment of the present disclosure. 
         FIG. 14  shows an example of a method for an SN belonging to a second RAT according to an embodiment of the present disclosure. 
         FIG. 15  shows an example of an AI device to which the technical features of the present disclosure can be applied. 
         FIG. 16  shows an example of an AI system to which the technical features of the present disclosure can be applied. 
     
    
    
     DETAILED DESCRIPTION 
     The technical features described below may be used by a communication standard by the 3rd generation partnership project (3GPP) standardization organization, a communication standard by the institute of electrical and electronics engineers (IEEE), etc. For example, the communication standards by the 3GPP standardization organization include long-term evolution (LTE) and/or evolution of LTE systems. The evolution of LTE systems includes LTE-advanced (LTE-A), LTE-A Pro, and/or 5G new radio (NR). The communication standard by the IEEE standardization organization includes a wireless local area network (WLAN) system such as IEEE 802.11a/b/g/n/ac/ax. The above system uses various multiple access technologies such as orthogonal frequency division multiple access (OFDMA) and/or single carrier frequency division multiple access (SC-FDMA) for downlink (DL) and/or uplink (UL). For example, only OFDMA may be used for DL and only SC-FDMA may be used for UL. Alternatively, OFDMA and SC-FDMA may be used for DL and/or UL. 
     In the present disclosure, the term “/” and “,” should be interpreted to indicate “and/or.” For instance, the expression “A/B” may mean “A and/or B.” Further, “A, B” may mean “A and/or B.” Further, “A/B/C” may mean “at least one of A, B, and/or C.” Also, “A, B, C” may mean “at least one of A, B, and/or C.” 
     Further, in the present disclosure, the term “or” should be interpreted to indicate “and/or.” For instance, the expression “A or B” may comprise 1) only A, 2) only B, and/or 3) both A and B. In other words, the term “or” in the present disclosure should be interpreted to indicate “additionally or alternatively.” 
     The following drawings are created to explain specific embodiments of the present disclosure. The names of the specific devices or the names of the specific signals/messages/fields shown in the drawings are provided by way of example, and thus the technical features of the present disclosure are not limited to the specific names used in the following drawings. 
       FIG. 1  shows examples of 5G usage scenarios to which the technical features of the present disclosure can be applied. 
     The 5G usage scenarios shown in  FIG. 1  are only exemplary, and the technical features of the present disclosure can be applied to other 5G usage scenarios which are not shown in  FIG. 1 . 
     Referring to  FIG. 1 , the three main requirements areas of 5G include (1) enhanced mobile broadband (eMBB) domain, (2) massive machine type communication (mMTC) area, and (3) ultra-reliable and low latency communications (URLLC) area. Some use cases may require multiple areas for optimization and, other use cases may only focus on only one key performance indicator (KPI). 5G is to support these various use cases in a flexible and reliable way. 
     eMBB focuses on across-the-board enhancements to the data rate, latency, user density, capacity and coverage of mobile broadband access. The eMBB aims ˜10 Gbps of throughput. eMBB far surpasses basic mobile Internet access and covers rich interactive work and media and entertainment applications in cloud and/or augmented reality. Data is one of the key drivers of 5G and may not be able to see dedicated voice services for the first time in the 5G era. In 5G, the voice is expected to be processed as an application simply using the data connection provided by the communication system. The main reason for the increased volume of traffic is an increase in the size of the content and an increase in the number of applications requiring high data rates. Streaming services (audio and video), interactive video and mobile Internet connectivity will become more common as more devices connect to the Internet. Many of these applications require always-on connectivity to push real-time information and notifications to the user. Cloud storage and applications are growing rapidly in mobile communication platforms, which can be applied to both work and entertainment. Cloud storage is a special use case that drives growth of uplink data rate. 5G is also used for remote tasks on the cloud and requires much lower end-to-end delay to maintain a good user experience when the tactile interface is used. In entertainment, for example, cloud games and video streaming are another key factor that increases the demand for mobile broadband capabilities. Entertainment is essential in smartphones and tablets anywhere, including high mobility environments such as trains, cars and airplanes. Another use case is augmented reality and information retrieval for entertainment. Here, augmented reality requires very low latency and instantaneous data amount. 
     mMTC is designed to enable communication between devices that are low-cost, massive in number and battery-driven, intended to support applications such as smart metering, logistics, and field and body sensors. mMTC aims ˜10 years on battery and/or ˜1 million devices/km2. mMTC allows seamless integration of embedded sensors in all areas and is one of the most widely used 5G applications. Potentially by 2020, internet-of-things (IoT) devices are expected to reach 20.4 billion. Industrial IoT is one of the areas where 5G plays a key role in enabling smart cities, asset tracking, smart utilities, agriculture and security infrastructures. 
     URLLC will make it possible for devices and machines to communicate with ultra-reliability, very low latency and high availability, making it ideal for vehicular communication, industrial control, factory automation, remote surgery, smart grids and public safety applications. URLLC aims ˜1 ms of latency. URLLC includes new services that will change the industry through links with ultra-reliability/low latency, such as remote control of key infrastructure and self-driving vehicles. The level of reliability and latency is essential for smart grid control, industrial automation, robotics, drones control and coordination. 
     Next, a plurality of use cases included in the triangle of  FIG. 1  will be described in more detail. 
     5G can complement fiber-to-the-home (FTTH) and cable-based broadband (or DOCSIS) as a means of delivering streams rated from hundreds of megabits per second to gigabits per second. This high speed can be required to deliver TVs with resolutions of 4K or more (6K, 8K and above) as well as virtual reality (VR) and augmented reality (AR). VR and AR applications include mostly immersive sporting events. Certain applications may require special network settings. For example, in the case of a VR game, a game company may need to integrate a core server with an edge network server of a network operator to minimize delay. 
     Automotive is expected to become an important new driver for 5G, with many use cases for mobile communications to vehicles. For example, entertainment for passengers demands high capacity and high mobile broadband at the same time. This is because future users will continue to expect high-quality connections regardless of their location and speed. Another use case in the automotive sector is an augmented reality dashboard. The driver can identify an object in the dark on top of what is being viewed through the front window through the augmented reality dashboard. The augmented reality dashboard displays information that will inform the driver about the object&#39;s distance and movement. In the future, the wireless module enables communication between vehicles, information exchange between the vehicle and the supporting infrastructure, and information exchange between the vehicle and other connected devices (e.g., devices accompanied by a pedestrian). The safety system allows the driver to guide the alternative course of action so that he can drive more safely, thereby reducing the risk of accidents. The next step will be a remotely controlled vehicle or self-driving vehicle. This requires a very reliable and very fast communication between different self-driving vehicles and between vehicles and infrastructure. In the future, a self-driving vehicle will perform all driving activities, and the driver will focus only on traffic that the vehicle itself cannot identify. The technical requirements of self-driving vehicles require ultra-low latency and high-speed reliability to increase traffic safety to a level not achievable by humans. 
     Smart cities and smart homes, which are referred to as smart societies, will be embedded in high density wireless sensor networks. The distributed network of intelligent sensors will identify conditions for cost and energy-efficient maintenance of a city or house. A similar setting can be performed for each home. Temperature sensors, windows and heating controllers, burglar alarms and appliances are all wirelessly connected. Many of these sensors typically require low data rate, low power and low cost. However, for example, real-time high-definition (HD) video may be required for certain types of devices for monitoring. 
     The consumption and distribution of energy, including heat or gas, is highly dispersed, requiring automated control of distributed sensor networks. The smart grid interconnects these sensors using digital information and communication technologies to collect and act on information. This information can include supplier and consumer behavior, allowing the smart grid to improve the distribution of fuel, such as electricity, in terms of efficiency, reliability, economy, production sustainability, and automated methods. The smart grid can be viewed as another sensor network with low latency. 
     The health sector has many applications that can benefit from mobile communications. Communication systems can support telemedicine to provide clinical care in remote locations. This can help to reduce barriers to distance and improve access to health services that are not continuously available in distant rural areas. It is also used to save lives in critical care and emergency situations. Mobile communication based wireless sensor networks can provide remote monitoring and sensors for parameters such as heart rate and blood pressure. 
     Wireless and mobile communications are becoming increasingly important in industrial applications. Wiring costs are high for installation and maintenance. Thus, the possibility of replacing a cable with a wireless link that can be reconfigured is an attractive opportunity in many industries. However, achieving this requires that wireless connections operate with similar delay, reliability, and capacity as cables and that their management is simplified. Low latency and very low error probabilities are new requirements that need to be connected to 5G. 
     Logistics and freight tracking are important use cases of mobile communications that enable tracking of inventory and packages anywhere using location based information systems. Use cases of logistics and freight tracking typically require low data rates, but require a large range and reliable location information. 
       FIG. 2  shows an example of a wireless communication system to which the technical features of the present disclosure can be applied. 
     Referring to  FIG. 2 , the wireless communication system may include a first device  210  and a second device  220 . 
     The first device  210  includes a base station, a network node, a transmitting UE, a receiving UE, a wireless device, a wireless communication device, a vehicle, a vehicle equipped with an autonomous driving function, a connected car, a drone, an unmanned aerial vehicle (UAV), an artificial intelligence (AI) module, a robot, an AR device, a VR device, a mixed reality (MR) device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a fin-tech device (or, a financial device), a security device, a climate/environmental device, a device related to 5G services, or a device related to the fourth industrial revolution. 
     The second device  220  includes a base station, a network node, a transmitting UE, a receiving UE, a wireless device, a wireless communication device, a vehicle, a vehicle equipped with an autonomous driving function, a connected car, a drone, a UAV, an AI module, a robot, an AR device, a VR device, an MR device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a fin-tech device (or, a financial device), a security device, a climate/environmental device, a device related to 5G services, or a device related to the fourth industrial revolution. 
     For example, the UE may include a mobile phone, a smart phone, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation device, a slate personal computer (PC), a tablet PC, an ultrabook, a wearable device (e.g., a smartwatch, a smart glass, a head mounted display (HMD)). For example, the HMD may be a display device worn on the head. For example, the HMD may be used to implement AR, VR and/or MR. 
     For example, the drone may be a flying object that is flying by a radio control signal without a person boarding it. For example, the VR device may include a device that implements an object or background in the virtual world. For example, the AR device may include a device that implements connection of an object and/or a background of a virtual world to an object and/or a background of the real world. For example, the MR device may include a device that implements fusion of an object and/or a background of a virtual world to an object and/or a background of the real world. For example, the hologram device may include a device that implements a 360-degree stereoscopic image by recording and playing stereoscopic information by utilizing a phenomenon of interference of light generated by the two laser lights meeting with each other, called holography. For example, the public safety device may include a video relay device or a video device that can be worn by the user&#39;s body. For example, the MTC device and the IoT device may be a device that do not require direct human intervention or manipulation. For example, the MTC device and the IoT device may include a smart meter, a vending machine, a thermometer, a smart bulb, a door lock and/or various sensors. For example, the medical device may be a device used for the purpose of diagnosing, treating, alleviating, handling, or preventing a disease. For example, the medical device may be a device used for the purpose of diagnosing, treating, alleviating, or correcting an injury or disorder. For example, the medical device may be a device used for the purpose of inspecting, replacing or modifying a structure or function. For example, the medical device may be a device used for the purpose of controlling pregnancy. For example, the medical device may include a treatment device, a surgical device, an (in vitro) diagnostic device, a hearing aid and/or a procedural device, etc. For example, a security device may be a device installed to prevent the risk that may occur and to maintain safety. For example, the security device may include a camera, a closed-circuit TV (CCTV), a recorder, or a black box. For example, the fin-tech device may be a device capable of providing financial services such as mobile payment. For example, the fin-tech device may include a payment device or a point of sales (POS). For example, the climate/environmental device may include a device for monitoring or predicting the climate/environment. 
     The first device  210  may include at least one or more processors, such as a processor  211 , at least one memory, such as a memory  212 , and at least one transceiver, such as a transceiver  213 . The processor  211  may perform the functions, procedures, and/or methods of the present disclosure described below. The processor  211  may perform one or more protocols. For example, the processor  211  may perform one or more layers of the air interface protocol. The memory  212  is connected to the processor  211  and may store various types of information and/or instructions. The transceiver  213  is connected to the processor  211  and may be controlled to transmit and receive wireless signals. 
     The second device  220  may include at least one or more processors, such as a processor  221 , at least one memory, such as a memory  222 , and at least one transceiver, such as a transceiver  223 . The processor  221  may perform the functions, procedures, and/or methods of the present disclosure described below. The processor  221  may perform one or more protocols. For example, the processor  221  may perform one or more layers of the air interface protocol. The memory  222  is connected to the processor  221  and may store various types of information and/or instructions. The transceiver  223  is connected to the processor  221  and may be controlled to transmit and receive wireless signals. 
     The memory  212 ,  222  may be connected internally or externally to the processor  211 ,  221 , or may be connected to other processors via a variety of technologies such as wired or wireless connections. 
     The first device  210  and/or the second device  220  may have more than one antenna. For example, antenna  214  and/or antenna  224  may be configured to transmit and receive wireless signals. 
       FIG. 3  shows an example of a wireless communication system to which the technical features of the present disclosure can be applied. 
     Specifically,  FIG. 3  shows a system architecture based on an evolved-UMTS terrestrial radio access network (E-UTRAN). The aforementioned LTE is a part of an evolved-UTMS (e-UMTS) using the E-UTRAN. 
     Referring to  FIG. 3 , the wireless communication system includes one or more user equipment (UE)  310 , an E-UTRAN and an evolved packet core (EPC). The UE  310  refers to a communication equipment carried by a user. The UE  310  may be fixed or mobile. The UE  310  may be referred to as another terminology, such as a mobile station (MS), a user terminal (UT), a subscriber station (SS), a wireless device, etc. 
     The E-UTRAN consists of one or more evolved NodeB (eNB)  320 . The eNB  320  provides the E-UTRA user plane and control plane protocol terminations towards the UE  10 . The eNB  320  is generally a fixed station that communicates with the UE  310 . The eNB  320  hosts the functions, such as inter-cell radio resource management (RRM), radio bearer (RB) control, connection mobility control, radio admission control, measurement configuration/provision, dynamic resource allocation (scheduler), etc. The eNB  320  may be referred to as another terminology, such as a base station (BS), a base transceiver system (BTS), an access point (AP), etc. 
     A downlink (DL) denotes communication from the eNB  320  to the UE  310 . An uplink (UL) denotes communication from the UE  310  to the eNB  320 . A sidelink (SL) denotes communication between the UEs  310 . In the DL, a transmitter may be a part of the eNB  320 , and a receiver may be a part of the UE  310 . In the UL, the transmitter may be a part of the UE  310 , and the receiver may be a part of the eNB  320 . In the SL, the transmitter and receiver may be a part of the UE  310 . 
     The EPC includes a mobility management entity (MME), a serving gateway (S-GW) and a packet data network (PDN) gateway (P-GW). The MME hosts the functions, such as non-access stratum (NAS) security, idle state mobility handling, evolved packet system (EPS) bearer control, etc. The S-GW hosts the functions, such as mobility anchoring, etc. The S-GW is a gateway having an E-UTRAN as an endpoint. For convenience, MME/S-GW  330  will be referred to herein simply as a “gateway,” but it is understood that this entity includes both the MME and S-GW. The P-GW hosts the functions, such as UE Internet protocol (IP) address allocation, packet filtering, etc. The P-GW is a gateway having a PDN as an endpoint. The P-GW is connected to an external network. 
     The UE  310  is connected to the eNB  320  by means of the Uu interface. The UEs  310  are interconnected with each other by means of the PC5 interface. The eNBs  320  are interconnected with each other by means of the X2 interface. The eNBs  320  are also connected by means of the S1 interface to the EPC, more specifically to the MME by means of the S1-MME interface and to the S-GW by means of the S1-U interface. The S1 interface supports a many-to-many relation between MMEs/S-GWs and eNBs. 
       FIG. 4  shows another example of a wireless communication system to which the technical features of the present disclosure can be applied. 
     Specifically,  FIG. 4  shows a system architecture based on a 5G NR. The entity used in the 5G NR (hereinafter, simply referred to as “NR”) may absorb some or all of the functions of the entities introduced in  FIG. 3  (e.g., eNB, MME, S-GW). The entity used in the NR may be identified by the name “NG” for distinction from the LTE/LTE-A. 
     Referring to  FIG. 4 , the wireless communication system includes one or more UE  410 , a next-generation RAN (NG-RAN) and a 5th generation core network (5GC). The NG-RAN consists of at least one NG-RAN node. The NG-RAN node is an entity corresponding to the eNB  320  shown in  FIG. 3 . The NG-RAN node consists of at least one gNB  421  and/or at least one ng-eNB  422 . The gNB  421  provides NR user plane and control plane protocol terminations towards the UE  410 . The ng-eNB  422  provides E-UTRA user plane and control plane protocol terminations towards the UE  410 . 
     The 5GC includes an access and mobility management function (AMF), a user plane function (UPF) and a session management function (SMF). The AMF hosts the functions, such as NAS security, idle state mobility handling, etc. The AMF is an entity including the functions of the conventional MME. The UPF hosts the functions, such as mobility anchoring, protocol data unit (PDU) handling. The UPF an entity including the functions of the conventional S-GW. The SMF hosts the functions, such as UE IP address allocation, PDU session control. 
     The gNBs  421  and ng-eNBs  422  are interconnected with each other by means of the Xn interface. The gNBs  421  and ng-eNBs  422  are also connected by means of the NG interfaces to the 5GC, more specifically to the AMF by means of the NG-C interface and to the UPF by means of the NG-U interface. 
     A protocol structure between network entities described above is described. On the system of  FIG. 3  and/or  FIG. 4 , layers of a radio interface protocol between the UE and the network (e.g., NG-RAN and/or E-UTRAN) may be classified into a first layer (L1), a second layer (L2), and a third layer (L3) based on the lower three layers of the open system interconnection (OSI) model that is well-known in the communication system. 
       FIG. 5  shows a block diagram of a user plane protocol stack to which the technical features of the present disclosure can be applied.  FIG. 6  shows a block diagram of a control plane protocol stack to which the technical features of the present disclosure can be applied. 
     The user/control plane protocol stacks shown in  FIG. 5  and  FIG. 6  are used in NR. However, user/control plane protocol stacks shown in  FIG. 5  and  FIG. 6  may be used in LTE/LTE-A without loss of generality, by replacing gNB/AMF with eNB/MME. 
     Referring to  FIG. 5  and  FIG. 6 , a physical (PHY) layer belonging to L1. The PHY layer offers information transfer services to media access control (MAC) sublayer and higher layers. The PHY layer offers to the MAC sublayer transport channels. Data between the MAC sublayer and the PHY layer is transferred via the transport channels. Between different PHY layers, i.e., between a PHY layer of a transmission side and a PHY layer of a reception side, data is transferred via the physical channels. 
     The MAC sublayer belongs to L2. The main services and functions of the MAC sublayer include mapping between logical channels and transport channels, multiplexing/de-multiplexing of MAC service data units (SDUs) belonging to one or different logical channels into/from transport blocks (TB) delivered to/from the physical layer on transport channels, scheduling information reporting, error correction through hybrid automatic repeat request (HARQ), priority handling between UEs by means of dynamic scheduling, priority handling between logical channels of one UE by means of logical channel prioritization (LCP), etc. The MAC sublayer offers to the radio link control (RLC) sublayer logical channels. 
     The RLC sublayer belong to L2. The RLC sublayer supports three transmission modes, i.e. transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM), in order to guarantee various quality of services (QoS) required by radio bearers. The main services and functions of the RLC sublayer depend on the transmission mode. For example, the RLC sublayer provides transfer of upper layer PDUs for all three modes, but provides error correction through ARQ for AM only. In LTE/LTE-A, the RLC sublayer provides concatenation, segmentation and reassembly of RLC SDUs (only for UM and AM data transfer) and re-segmentation of RLC data PDUs (only for AM data transfer). In NR, the RLC sublayer provides segmentation (only for AM and UM) and re-segmentation (only for AM) of RLC SDUs and reassembly of SDU (only for AM and UM). That is, the NR does not support concatenation of RLC SDUs. The RLC sublayer offers to the packet data convergence protocol (PDCP) sublayer RLC channels. 
     The PDCP sublayer belong to L2. The main services and functions of the PDCP sublayer for the user plane include header compression and decompression, transfer of user data, duplicate detection, PDCP PDU routing, retransmission of PDCP SDUs, ciphering and deciphering, etc. The main services and functions of the PDCP sublayer for the control plane include ciphering and integrity protection, transfer of control plane data, etc. 
     The service data adaptation protocol (SDAP) sublayer belong to L2. The SDAP sublayer is only defined in the user plane. The SDAP sublayer is only defined for NR. The main services and functions of SDAP include, mapping between a QoS flow and a data radio bearer (DRB), and marking QoS flow ID (QFI) in both DL and UL packets. The SDAP sublayer offers to 5GC QoS flows. 
     A radio resource control (RRC) layer belongs to L3. The RRC layer is only defined in the control plane. The RRC layer controls radio resources between the UE and the network. To this end, the RRC layer exchanges RRC messages between the UE and the BS. The main services and functions of the RRC layer include broadcast of system information related to AS and NAS, paging, establishment, maintenance and release of an RRC connection between the UE and the network, security functions including key management, establishment, configuration, maintenance and release of radio bearers, mobility functions, QoS management functions, UE measurement reporting and control of the reporting, NAS message transfer to/from NAS from/to UE. 
     In other words, the RRC layer controls logical channels, transport channels, and physical channels in relation to the configuration, reconfiguration, and release of radio bearers. A radio bearer refers to a logical path provided by L1 (PHY layer) and L2 (MAC/RLC/PDCP/SDAP sublayer) for data transmission between a UE and a network. Setting the radio bearer means defining the characteristics of the radio protocol layer and the channel for providing a specific service, and setting each specific parameter and operation method. Radio bearer may be divided into signaling RB (SRB) and data RB (DRB). 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. 
     An RRC state indicates whether an RRC layer of the UE is logically connected to an RRC layer of the E-UTRAN. In LTE/LTE-A, when the RRC connection is established between the RRC layer of the UE and the RRC layer of the E-UTRAN, the UE is in the RRC connected state (RRC_CONNECTED). Otherwise, the UE is in the RRC idle state (RRC_IDLE). In NR, the RRC inactive state (RRC_INACTIVE) is additionally introduced. RRC_INACTIVE may be used for various purposes. For example, the massive machine type communications (MMTC) UEs can be efficiently managed in RRC_INACTIVE. When a specific condition is satisfied, transition is made from one of the above three states to the other. 
     A predetermined operation may be performed according to the RRC state. In RRC_IDLE, public land mobile network (PLMN) selection, broadcast of system information (SI), cell re-selection mobility, core network (CN) paging and discontinuous reception (DRX) configured by NAS may be performed. The UE shall have been allocated an identifier (ID) which uniquely identifies the UE in a tracking area. No RRC context stored in the BS. 
     In RRC_CONNECTED, the UE has an RRC connection with the network (i.e. E-UTRAN/NG-RAN). Network-CN connection (both C/U-planes) is also established for UE. The UE AS context is stored in the network and the UE. The RAN knows the cell which the UE belongs to. The network can transmit and/or receive data to/from UE. Network controlled mobility including measurement is also performed. 
     Most of operations performed in RRC_IDLE may be performed in RRC_INACTIVE. But, instead of CN paging in RRC_IDLE, RAN paging is performed in RRC_INACTIVE. In other words, in RRC_IDLE, paging for mobile terminated (MT) data is initiated by core network and paging area is managed by core network. In RRC_INACTIVE, paging is initiated by NG-RAN, and RAN-based notification area (RNA) is managed by NG-RAN. Further, instead of DRX for CN paging configured by NAS in RRC_IDLE, DRX for RAN paging is configured by NG-RAN in RRC_INACTIVE. Meanwhile, in RRC_INACTIVE, 5GC-NG-RAN connection (both C/U-planes) is established for UE, and the UE AS context is stored in NG-RAN and the UE. NG-RAN knows the RNA which the UE belongs to. 
     NAS layer is located at the top of the RRC layer. The NAS control protocol performs the functions, such as authentication, mobility management, security control. 
     NR supports multiple numerology (or, subcarrier spacing (SCS)) to support various 5G services. For example, when the SCS is 15 kHz, wide area in traditional cellular bands may be supported. When the SCS is 30 kHz/60 kHz, dense-urban, lower latency and wider carrier bandwidth may be supported. When the SCS is 60 kHz or higher, a bandwidth greater than 24.25 GHz may be supported to overcome phase noise. 
     The NR frequency band may be defined as two types of frequency range, i.e., FR1 and FR2. The numerical value of the frequency range may be changed. For example, the frequency ranges of the two types (FR1 and FR2) may be as shown in Table 1 below. For ease of explanation, in the frequency ranges used in the NR system, FR1 may mean “sub 6 GHz range”, FR2 may mean “above 6 GHz range,” and may be referred to as millimeter wave (mmW). 
     
       
         
           
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Frequency Range 
                 Corresponding 
                   
               
               
                 designation 
                 frequency range 
                 Subcarrier Spacing 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 FR1 
                  450 MHz-6000 MHz 
                 15, 30, 60 
                 kHz 
               
               
                 FR2 
                 24250 MHz-52600 MHz 
                 60, 120, 240 
                 kHz 
               
               
                   
               
            
           
         
       
     
     As mentioned above, the numerical value of the frequency range of the NR system may be changed. For example, FR1 may include a frequency band of 410 MHz to 7125 MHz as shown in Table 2 below. That is, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or more. For example, a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or more included in FR1 may include an unlicensed band. Unlicensed bands may be used for a variety of purposes, for example for communication for vehicles (e.g., autonomous driving). 
     
       
         
           
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 Frequency Range 
                 Corresponding 
                   
               
               
                 designation 
                 frequency range 
                 Subcarrier Spacing 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 FR1 
                  410 MHz-7125 MHz 
                 15, 30, 60 
                 kHz 
               
               
                 FR2 
                 24250 MHz-52600 MHz 
                 60, 120, 240 
                 kHz 
               
               
                   
               
            
           
         
       
     
     Multi radio access technology (RAT) dual connectivity is described. Section 4 of 3GPP TS 37.340 V15.3.0 (2018-09) can be referred. 
     Multi-RAT dual connectivity (MR-DC) is a generalization of the intra-E-UTRA dual connectivity (DC), where a multiple reception (Rx)/transmission (Tx) UE may be configured to utilize resources provided by two different nodes connected via non-ideal backhaul, one providing E-UTRA access and the other one providing NR access. One node acts as the master node (MN) and the other as the secondary node (SN). The MN and SN are connected via a network interface and at least the MN is connected to the core network. 
     MR-DC is designed based on the assumption of non-ideal backhaul between the different nodes but can also be used in case of ideal backhaul. 
     E-UTRAN supports MR-DC via E-UTRA-NR dual connectivity (EN-DC), in which a UE is connected to one eNB that acts as a MN and one en-gNB that acts as a SN. The eNB is connected to the EPC via the 51 interface and to the en-gNB via the X2 interface. The en-gNB might also be connected to the EPC via the S1-U interface and other en-gNBs via the X2-U interface. EN-DC may be referred to as “Option 3” of MR-DC. 
     NG-RAN supports NG-RAN E-UTRA-NR dual connectivity (NGEN-DC), in which a UE is connected to one ng-eNB that acts as a MN and one gNB that acts as a SN. The ng-eNB is connected to the 5GC and the gNB is connected to the ng-eNB via the Xn interface. NGEN-DC may be referred to as “Option 7” of MR-DC. 
     NG-RAN supports NR-E-UTRA dual connectivity (NE-DC), in which a UE is connected to one gNB that acts as a MN and one ng-eNB that acts as a SN. The gNB is connected to 5GC and the ng-eNB is connected to the gNB via the Xn interface. NE-DC may be referred to as “Option 4” of MR-DC. 
     For control plane radio protocol architecture, in MR-DC, the UE has a single RRC state, based on the MN RRC and a single C-plane connection towards the core network. Each radio node has its own RRC entity (E-UTRA version if the node is an eNB or NR version if the node is a gNB) which can generate RRC PDUs to be sent to the UE. 
     RRC PDUs generated by the SN can be transported via the MN to the UE. The MN always sends the initial SN RRC configuration via master cell group (MCG) SRB (SRB1), but subsequent reconfigurations may be transported via MN or SN. When transporting RRC PDU from the SN, the MN does not modify the UE configuration provided by the SN. 
     In EN-DC, at initial connection establishment, SRB1 uses E-UTRA PDCP. After initial connection establishment, MCG SRBs (SRB1 and SRB2) can be configured by the network to use either E-UTRA PDCP or NR PDCP. A PDCP version change (release of old PDCP and establish of new PDCP) of SRBs can be supported in either direction (i.e., from E-UTRA PDCP to NR PDCP or vice versa) via a handover procedure (reconfiguration with mobility) or, for the initial change from E-UTRA PDCP to NR PDCP, with a reconfiguration without mobility, when the network knows there is no UL data in buffer and before the initial security activation. For EN-DC capable UEs, NR PDCP can be configured for DRBs and SRBs also before EN-DC is configured. 
     If the SN is a gNB (i.e., for EN-DC and NGEN-DC), the UE can be configured to establish a SRB with the SN (SRB3) to enable RRC PDUs for the SN to be sent directly between the UE and the SN. RRC PDUs for the SN can only be transported directly to the UE for SN RRC reconfiguration not requiring any coordination with the MN. Measurement reporting for mobility within the SN can be done directly from the UE to the SN if SRB3 is configured. 
     Split SRB is supported for all MR-DC options, allowing duplication of RRC PDUs generated by the MN, via the direct path and via the SN. Split SRB uses NR PDCP. 
     In EN-DC, the secondary cell group (SCG) configuration is kept in the UE during suspension. The UE releases the SCG configuration (but not the radio bearer configuration) during resumption initiation. 
     For user plane radio protocol architecture, in MR-DC, from a UE perspective, three bearer types exist: MCG bearer, SCG bearer and split bearer. 
     For EN-DC, the network can configure either E-UTRA PDCP or NR PDCP for MN terminated MCG bearers while NR PDCP is always used for all other bearers. 
     In MR-DC with 5GC, NR PDCP is always used for all bearer types. In NGEN-DC, E-UTRA RLC/MAC is used in the MN while NR RLC/MAC is used in the SN. In NE-DC, NR RLC/MAC is used in the MN while E-UTRA RLC/MAC is used in the SN. 
     From a network perspective, each bearer (MCG, SCG and split bearer) can be terminated either in MN or in SN. 
     Even if only SCG bearers are configured for a UE, for SRB1 and SRB2 the logical channels are always configured at least in the MCG, i.e., this is still an MR-DC configuration and a primary cell (PCell) always exists. 
     If only MCG bearers are configured for a UE, i.e., there is no SCG, this is still considered an MR-DC configuration, as long as at least one of the bearers is terminated in the SN. 
     For control plane network interfaces, in MR-DC, there is an interface between the MN and the SN for control plane signaling and coordination. For each MR-DC UE, there is also one control plane connection between the MN and a corresponding CN entity. The MN and the SN involved in MR-DC for a certain UE control their radio resources and are primarily responsible for allocating radio resources of their cells. 
     In MR-DC with EPC (EN-DC), the involved core network entity is the MME. S1-MME is terminated in MN and the MN and the SN are interconnected via X2-C. 
     In MR-DC with 5GC (NGEN-DC, NE-DC), the involved core network entity is the AMF. NG-C is terminated in the MN and the MN and the SN are interconnected via Xn-C. 
     For user plane network interfaces, there are different U-plane connectivity options of the MN and SN involved in MR-DC for a certain UE. The U-plane connectivity depends on the bearer option configured: 
     (1) For MN terminated bearers, the user plane connection to the CN entity is terminated in the MN; 
     (2) For SN terminated bearers, the user plane connection to the CN entity is terminated in the SN; 
     (3) The transport of user plane data over the Uu either involves MCG or SCG radio resources or both:
         For MCG bearers, only MCG radio resources are involved;   For SCG bearers, only SCG radio resources are involved;   For split bearers, both MCG and SCG radio resources are involved.       

     (4) For split bearers, MN terminated SCG bearers and SN terminated MCG bearers, PDCP data is transferred between the MN and the SN via the MN-SN user plane interface. 
     For MR-DC with EPC (EN-DC), X2-U interface is the user plane interface between MN and SN, and S1-U is the user plane interface between the MN, the SN or both and the S-GW. 
     For MR-DC with 5GC (NGEN-DC, NE-DC), Xn-U interface is the user plane interface between MN and SN, and NG-U is the user plane interface between the MN, the SN or both and the UPF. 
     Support for vehicle-to-vehicle (V2V) and vehicle-to-everything (V2X) services has been introduced in LTE during Releases 14 and 15, in order to expand the 3GPP platform to the automotive industry. These work items defined an LTE sidelink suitable for vehicular applications, and complementary enhancements to the cellular infrastructure. 
     Further to this work, requirements for support of enhanced V2X use cases have been defined in 5G LTE/NR, which are broadly arranged into four use case groups: 
     1) Vehicles platooning enables the vehicles to dynamically form a platoon travelling together. All the vehicles in the platoon obtain information from the leading vehicle to manage this platoon. These information allow the vehicles to drive closer than normal in a coordinated manner, going to the same direction and travelling together. 
     2) Extended Sensors enables the exchange of raw or processed data gathered through local sensors or live video images among vehicles, road site units, devices of pedestrian and V2X application servers. The vehicles can increase the perception of their environment beyond of what their own sensors can detect and have a more broad and holistic view of the local situation. High data rate is one of the key characteristics. 
     3) Advanced driving enables semi-automated or full-automated driving. Each vehicle and/or RSU shares its own perception data obtained from its local sensors with vehicles in proximity and that allows vehicles to synchronize and coordinate their trajectories or maneuvers. Each vehicle shares its driving intention with vehicles in proximity too. 
     4) Remote driving enables a remote driver or a V2X application to operate a remote vehicle for those passengers who cannot drive by themselves or remote vehicles located in dangerous environments. For a case where variation is limited and routes are predictable, such as public transportation, driving based on cloud computing can be used. High reliability and low latency are the main requirements. 
     NR V2X may complement LTE V2X for advanced V2X services and support interworking with LTE V2X. NR V2X is estimated to have two modes for resource allocation for V2X sidelink communication between UEs (e.g., vehicle, pedestrian UE). The first mode is dedicated signaling based mode, in which a UE can request to gNB for a dedicated resource grant for V2X sidelink communication. The second mode is broadcast signaling based mode, in which a UE can get information on resource pool and/or resource grant through broadcast signaling. 
     Meanwhile, in 5G NR, as described above, dual connectivity is important feature to support for real deployments. In addition, NR V2X is also to be designed based on NR architecture and physical framework. Due to adoption of dual connectivity architecture in 5G NR, physical resource handling for NR V2X, e.g., dedicated signaling based mode and/or broadcast signaling based mode, may include issues to be solved for NR V2X. 
       FIG. 7  shows an example of resource allocation for sidelink communication according to an embodiment of the present disclosure. 
       FIG. 7  shows a case of resource allocation for V2X communication in EN-DC (i.e., Option 3 of MR-DC) or NGEN-DC (i.e., Option 7 of MR-DC). That is, eNB and/or ng-eNB may act as an MN (i.e., MeNB), and the gNB may act as an SN (i.e., SgNB). In  FIG. 7 , SN takes the role of signaling to UE. 
     In step S 700 , the core network entity (e.g., MME/AMF) transmits authorization information on NR radio resource to the MeNB for a UE. The authorization information may inform whether the UE is authorized as vehicle UE, pedestrian UE or other UE on the NR radio resource. 
     Upon receiving the authorization information from the core network entity, in step S 710 , the MeNB may decide whether to configure the NR radio resources to the UE directly or not. 
     If the MeNB decides not to configure the NR radio resources to the UE directly (i.e., let the SgNB decide to configure NR radio resources to the UE or not) based on the authorization information and/or pre-configuration, in step S 720 , the MeNB transmits the authorization information on the NR radio resource to the SgNB. 
     Upon receiving the authorization information from the MeNB, in step S 730 , the SgNB decides/configures specific NR radio resources for the UE to be used when the UE requests. The specific NR radio resources for the UE to be used may be different depending on the UE type (e.g., vehicle UE, pedestrian UE or other UE). 
     In step S 740 , the UE may request the NR radio resource for V2X communication with the indication of UE type (e.g., vehicle UE, pedestrian UE or other UE) to the SgNB directly. 
     Based on the indication of UE type received from the UE in step S 740  and/or the authorization information received from the MeNB in step S 720 , in step S 750 , the SgNB transmits a dedicated signaling to the UE with resource configuration for the specific NR radio resources. 
     Upon receiving the resources configuration, the UE may use the radio resources for V2X communication. 
       FIG. 8  shows another example of resource allocation for sidelink communication according to an embodiment of the present disclosure. 
       FIG. 8  shows a case of resource allocation for V2X communication in EN-DC (i.e., Option 3 of MR-DC) or NGEN-DC (i.e., Option 7 of MR-DC). That is, eNB and/or ng-eNB may act as an MN (i.e., MeNB), and the gNB may act as an SN (i.e., SgNB). In  FIG. 8 , MN takes the role of signaling to UE. 
     In step S 800 , the core network entity (e.g., MME/AMF) transmits authorization information on NR radio resource to the MeNB for a UE. The authorization information may inform whether the UE is authorized as vehicle UE, pedestrian UE or other UE on the NR radio resource. 
     Upon receiving the authorization information from the core network entity, in step S 810 , the MeNB decides to configure the NR radio resources to the UE directly (i.e., transmit NR radio resources configuration to the UE directly) based on the authorization information and/or pre-configuration. 
     In step S 820 , the UE may request radio resource for V2X communication to the MeNB. The request for the radio resource for V2X communication may include indication on NR radio resources. The indication on NR radio resource may be included with NR support UE type or other indication. 
     In step S 830 , the MeNB requests NR resource allocation (e.g., NR resource grant) to the SgNB for the UE. The request for the NR resource allocation may include the authorization information (e.g., vehicle UE, pedestrian UE or other UE). Alternatively, the authorization information may be received from the MeNB in the initial SgNB Addition/Modification procedures in advance. The NR resource allocation may be different depending on the UE type (e.g., vehicle UE, pedestrian UE or other UE). 
     In step S 840 , the SgNB uses the authorization information received from the MeNB and decides the specific NR radio resources for the UE (e.g., vehicle UE, pedestrian UE or other UE). The specific NR radio resources for the UE may be different depending on the UE type (e.g., vehicle UE, pedestrian UE or other UE). 
     In step S 850 , the SgNB gives a response to the MeNB on the specific NR radio resource for the UE. 
     In step S 860 , the MeNB transmits a dedicated signaling to the UE with resource configuration for the specific NR radio resources. 
     Upon receiving the resources configuration, the UE may use the radio resources for V2X communication. 
       FIG. 9  shows another example of resource allocation for sidelink communication according to an embodiment of the present disclosure. 
       FIG. 9  shows a case of resource allocation for V2X communication in NE-DC (i.e., Option 4 of MR-DC). That is, gNB may act as an MN (i.e., MgNB), and the ng-eNB may act as an SN (i.e., SeNB). In  FIG. 9 , MN takes the role of signaling to UE. 
     In step S 900 , the AMF transmits authorization information on LTE radio resource to the MgNB for a UE. The authorization information may inform whether the UE is authorized as vehicle UE, pedestrian UE or other UE on the LTE radio resource. 
     Upon receiving the authorization information from the AMF, in step S 910 , the MgNB decides to configure the LTE radio resources to the UE directly (i.e., transmit LTE radio resources configuration to the UE directly) based on the authorization information and/or pre-configuration. 
     In step S 920 , the UE may request radio resource for V2X communication to the MgNB. The request for the radio resource for V2X communication may include indication on LTE radio resources. The indication on LTE radio resource may be included with LTE support UE type or other indication. 
     In step S 930 , the MgNB requests LTE resource allocation (e.g., LTE resource grant) to the SeNB for the UE. The request for the LTE resource allocation may include the authorization information (e.g., vehicle UE, pedestrian UE or other UE). Alternatively, the authorization information may be received from the MgNB in the initial SeNB Addition/Modification procedures in advance. The LTE resource allocation may be different depending on the UE type (e.g., vehicle UE, pedestrian UE or other UE). 
     In step S 940 , the SeNB uses the authorization information received from the MgNB and decides the specific LTE radio resources for the UE (e.g., vehicle UE, pedestrian UE or other UE). The specific LTE radio resources for the UE may be different depending on the UE type (e.g., vehicle UE, pedestrian UE or other UE). 
     In step S 950 , the SeNB gives a response to the MgNB on the specific LTE radio resource for the UE. 
     In step S 960 , the MgNB transmits a dedicated signaling to the UE with resource configuration for the specific LTE radio resources. 
     Upon receiving the resources configuration, the UE may use the radio resources for V2X communication. 
       FIG. 10  shows another example of resource allocation for sidelink communication according to an embodiment of the present disclosure. 
       FIG. 10  shows a case of resource allocation for V2X communication in NE-DC (i.e., Option 4 of MR-DC). That is, gNB may act as an MN (i.e., MgNB), and the ng-eNB may act as an SN (i.e., SeNB). In  FIG. 10 , SN takes the role of signaling to UE. 
     In step S 1000 , the AMF transmits authorization information on LTE radio resource to the MgNB for a UE. The authorization information may inform whether the UE is authorized as vehicle UE, pedestrian UE or other UE on the LTE radio resource. 
     Upon receiving the authorization information from the AMF, in step S 1010 , the MgNB may decide whether to configure the LTE radio resources to the UE directly or not. 
     If the MgNB decides not to configure the LTE radio resources to the UE directly (i.e., let the SeNB decide to configure LTE radio resources to the UE or not) based on the authorization information and/or pre-configuration, in step S 1020 , the MgNB transmits the authorization information on the LTE radio resource to the SeNB. 
     Upon receiving the authorization information from the MgNB, in step S 1030 , the SeNB decides/configures specific LTE radio resources for the UE to be used when the UE requests. The specific LTE radio resources for the UE to be used may be different depending on the UE type (e.g., vehicle UE, pedestrian UE or other UE). 
     In step S 1040 , the UE may request the LTE radio resource for V2X communication with the indication of UE type (e.g., vehicle UE, pedestrian UE or other UE) to the SeNB directly. The request for the specific LTE radio resource may be include with LTE support UE type or other indication. 
     Based on the indication of UE type received from the UE in step S 1040  and/or the authorization information received from the MgNB in step S 1020 , in step S 1050 , the SeNB transmits a dedicated signaling to the UE with resource configuration for the specific LTE radio resources. 
     Upon receiving the resources configuration, the UE may use the radio resources for V2X communication. 
       FIG. 11  shows another example of resource allocation for sidelink communication according to an embodiment of the present disclosure. 
       FIG. 11  shows a case of dedicated signaling to UE on resource allocation for V2X communication in EN-DC (i.e., Option 3 of MR-DC) or NGEN-DC (i.e., Option 7 of MR-DC). That is, eNB and/or ng-eNB may act as an MN (i.e., MeNB), and the gNB may act as an SN (i.e., SgNB). In  FIG. 11 , MN takes the role of signaling for SN resource information to UE in a cell-specific procedure. 
     It may be assumed that the MeNB has already obtained the authorization information (e.g., vehicle UE, pedestrian UE or other UE) from the core network entity. The authorization information may be referred to when the MeNB decides the specific radio resources for the corresponding UE, i.e., vehicle UE or pedestrian UE or other V2X service (e.g., automatic driving service, remote medical service, etc.). 
     In step S 1100 , the MeNB may request the NR resource pool to the SgNB for V2X communication. The request for the NR resource pool may include specific request on the resource pool for vehicle UE or the resource pool for pedestrian UE or other V2X service (e.g., automatic driving service, remote medical service, etc.). This step may be optional if the SgNB can notify to the MeNB the corresponding information automatically/initiatively. 
     In step S 1110 , the SgNB notifies and/or gives response to the MeNB about information on the NR resource pool for V2X communication. The resource pool can be UE type specific, i.e., a resource pool for vehicle UE, a resource pool for pedestrian UE, a resource pool for specific other V2X service (e.g., automatic driving service, remote medical service, etc.). The resource pool can be modified by the SgNB with time going. The SgNB may notify to the MeNB with information on the updated resource pool in case it changed. 
     In step S 1120 , the UE requests to the MeNB on radio resources for V2X communication. The request for the radio resource for V2X communication may include indication on NR radio resources. The indication on NR radio resource may be included with NR support UE type or other V2X service indication (e.g., automatic driving service, remote medical service, etc.). 
     The MeNB uses the authorization information and information on the NR resource pool for V2X communication received from the SgNB in step S 1110  to decide the specific NR radio resources for the UE (e.g., vehicle UE, pedestrian UE or other UE). The specific NR radio resources for the UE may be different depending on the UE type (e.g., vehicle UE, pedestrian UE or other V2X service). The indication received from the UE in step S 1120  may also be referred to. 
     In step S 1130 , the MeNB transmits a dedicated signaling to the UE with resource configuration for the NR radio resources. 
     Upon receiving the resources configuration, the UE may use the radio resources for V2X communication. 
       FIG. 12  shows another example of resource allocation for sidelink communication according to an embodiment of the present disclosure. 
       FIG. 12  shows a case of broadcast signaling to UE on resource allocation for V2X communication in EN-DC (i.e., Option 3 of MR-DC) or NGEN-DC (i.e., Option 7 of MR-DC). That is, eNB and/or ng-eNB may act as an MN (i.e., MeNB), and the gNB may act as an SN (i.e., SgNB). In  FIG. 12 , MN takes the role of signaling for SN resource information to UE in a cell-specific procedure. 
     It may be assumed that the MeNB has already obtained the authorization information (e.g., vehicle UE, pedestrian UE or other UE) from the core network entity. The authorization information may be referred to when the MeNB decides the specific radio resources for the corresponding UE, i.e., vehicle UE or pedestrian UE or other V2X service (e.g., automatic driving service, remote medical service, etc.). 
     In step S 1200 , the MeNB may request the NR resource pool to the SgNB for V2X communication. The request for the NR resource pool may include specific request on the resource pool for vehicle UE or the resource pool for pedestrian UE or other V2X service (e.g., automatic driving service, remote medical service, etc.). This step may be optional if the SgNB can notify to the MeNB the corresponding information automatically/initiatively. 
     In step S 1210 , the SgNB notifies and/or gives response to the MeNB about information on the NR resource pool for V2X communication. The resource pool can be UE type specific, i.e., a resource pool for vehicle UE, a resource pool for pedestrian UE, a resource pool for specific other V2X service (e.g., automatic driving service, remote medical service, etc.). The resource pool can be modified by the SgNB with time going. The SgNB may notify to the MeNB with information on the updated resource pool in case it changed. 
     The MeNB uses the information on the NR resource pool for V2X communication received from the SgNB in step S 1210  to decide how to broadcast the information on the NR resource pool for V2X communication to UEs. 
     In step S 1220 , the MeNB transmits a broadcast signaling including the information on the NR resource pool for V2X communication to UEs. The information on the NR resource pool for V2X communication may be different depending on the UE type or V2X services. 
     Upon receiving the information on the NR resource pool for V2X communication, the UE may use the NR resource pool for V2X communication. 
     Meanwhile, the examples shown in  FIG. 11  and/or  FIG. 12  according to an embodiment of the present disclosure can be applied in NE-DC (i.e., Option 4 of MR-DC). In this case, the MeNB should be changed into MgNB and SgNB should be changed into SeNB in the description above. Furthermore, NR resource should be LTE resource. 
       FIG. 13  shows an example of a method for an MN belonging to a first RAT according to an embodiment of the present disclosure. 
       FIG. 13  describes a resource allocation for V2X communication in perspective of MN based on the case described in  FIG. 8  above. In  FIG. 13 , the first RAT may be LTE, and the second RAT may be a 5G NR. The MN may be an eNB, the SN may be an en-gNB, and the core network node may be an MME. Alternatively, the MN may be an ng-eNB, the SN may be a gNB, and the core network node may be an AMF. The wireless device may be in communication with at least one of a mobile device, a network, and/or autonomous vehicles other than the wireless device. 
     In step S 1300 , the MN may receive authorization information on the second RAT for the wireless device from the core network node. The authorization information may inform at least one of a vehicle UE, a pedestrian UE or other UE. The MN may determine to transmit a message to the wireless device directly based on the authorization information and/or a per-configuration. 
     In step S 1310 , the MN transmits a request for a radio resource of the second RAT to a secondary node (SN) belonging to the second RAT. The request includes the authorization information on the second RAT for the wireless device. 
     The MN may receive a resource request for V2X communication from the wireless device. The resource request for V2X communication may include information for a NR support UE type. 
     In step S 1320 , the MN receives information on the radio resource from the secondary node. The radio resource may depend on a type of the wireless device. 
     In step S 1330 , the MN transmits a message to the wireless device based on the information on the radio resource. 
       FIG. 14  shows an example of a method for an SN belonging to a second RAT according to an embodiment of the present disclosure. 
       FIG. 14  describes a resource allocation for V2X communication in perspective of SN based on the case described in  FIG. 8  above. In  FIG. 14 , the first RAT may be LTE, and the second RAT may be a 5G NR. The MN may be an eNB, the SN may be an en-gNB, and the core network node may be an MME. Alternatively, the MN may be an ng-eNB, the SN may be a gNB, and the core network node may be an AMF. The wireless device may be in communication with at least one of a mobile device, a network, and/or autonomous vehicles other than the wireless device. 
     In step S 1400 , the SN receives a request for a radio resource of the second RAT from the MN belonging to the first RAT. The request includes authorization information on the second RAT for a wireless device. 
     In step S 1410 , the SN determines the radio resource based on the authorization information and a resource pool. The radio resource may depend on a type of the wireless device. 
     In step S 1420 , the SN transmits information on the radio resource to the MN. The present disclosure may be applied to various future technologies, such as AI. 
     &lt;AI&gt; 
     AI refers to artificial intelligence and/or the field of studying methodology for making it. Machine learning is a field of studying methodologies that define and solve various problems dealt with in AI. Machine learning may be defined as an algorithm that enhances the performance of a task through a steady experience with any task. 
     An artificial neural network (ANN) is a model used in machine learning. It can mean a whole model of problem-solving ability, consisting of artificial neurons (nodes) that form a network of synapses. An ANN can be defined by a connection pattern between neurons in different layers, a learning process for updating model parameters, and/or an activation function for generating an output value. An ANN may include an input layer, an output layer, and optionally one or more hidden layers. Each layer may contain one or more neurons, and an ANN may include a synapse that links neurons to neurons. In an ANN, each neuron can output a summation of the activation function for input signals, weights, and deflections input through the synapse. Model parameters are parameters determined through learning, including deflection of neurons and/or weights of synaptic connections. The hyper-parameter means a parameter to be set in the machine learning algorithm before learning, and includes a learning rate, a repetition number, a mini batch size, an initialization function, etc. The objective of the ANN learning can be seen as determining the model parameters that minimize the loss function. The loss function can be used as an index to determine optimal model parameters in learning process of ANN. 
     Machine learning can be divided into supervised learning, unsupervised learning, and reinforcement learning, depending on the learning method. Supervised learning is a method of learning ANN with labels given to learning data. Labels are the answers (or result values) that ANN must infer when learning data is input to ANN. Unsupervised learning can mean a method of learning ANN without labels given to learning data. Reinforcement learning can mean a learning method in which an agent defined in an environment learns to select a behavior and/or sequence of actions that maximizes cumulative compensation in each state. 
     Machine learning, which is implemented as a deep neural network (DNN) that includes multiple hidden layers among ANN, is also called deep learning. Deep learning is part of machine learning. In the following, machine learning is used to mean deep learning. 
     &lt;Autonomous-driving/self-driving&gt; 
     The autonomous-driving refers to a technique of self-driving, and an autonomous vehicle refers to a vehicle that travels without a user&#39;s operation or with a minimum operation of a user. For example, autonomous-driving may include techniques for maintaining a lane while driving, techniques for automatically controlling speed such as adaptive cruise control, techniques for automatically traveling along a predetermined route, and techniques for traveling by setting a route automatically when a destination is set. The autonomous vehicle may include a vehicle having only an internal combustion engine, a hybrid vehicle having an internal combustion engine and an electric motor together, and an electric vehicle having only an electric motor, and may include not only an automobile but also a train, a motorcycle, etc. The autonomous vehicle can be regarded as a robot having an autonomous driving function. 
       FIG. 15  shows an example of an AI device to which the technical features of the present disclosure can be applied. 
     The AI device  1500  may be implemented as a stationary device or a mobile device, such as a TV, a projector, a mobile phone, a smartphone, a desktop computer, a notebook, a digital broadcasting terminal, a PDA, a PMP, a navigation device, a tablet PC, a wearable device, a set-top box (STB), a digital multimedia broadcasting (DMB) receiver, a radio, a washing machine, a refrigerator, a digital signage, a robot, a vehicle, etc. 
     Referring to  FIG. 15 , the AI device  1500  may include a communication part  1510 , an input part  1520 , a learning processor  1530 , a sensing part  1540 , an output part  1550 , a memory  1560 , and a processor  1570 . 
     The communication part  1510  can transmit and/or receive data to and/or from external devices such as the AI devices and the AI server using wire and/or wireless communication technology. For example, the communication part  1510  can transmit and/or receive sensor information, a user input, a learning model, and a control signal with external devices. The communication technology used by the communication part  1510  may include a global system for mobile communication (GSM), a code division multiple access (CDMA), an LTE/LTE-A, a 5G, a WLAN, a Wi-Fi, Bluetooth™, radio frequency identification (RFID), infrared data association (IrDA), ZigBee, and/or near field communication (NFC). 
     The input part  1520  can acquire various kinds of data. The input part  1520  may include a camera for inputting a video signal, a microphone for receiving an audio signal, and a user input part for receiving information from a user. A camera and/or a microphone may be treated as a sensor, and a signal obtained from a camera and/or a microphone may be referred to as sensing data and/or sensor information. The input part  1520  can acquire input data to be used when acquiring an output using learning data and a learning model for model learning. The input part  1520  may obtain raw input data, in which case the processor  1570  or the learning processor  1530  may extract input features by preprocessing the input data. 
     The learning processor  1530  may learn a model composed of an ANN using learning data. The learned ANN can be referred to as a learning model. The learning model can be used to infer result values for new input data rather than learning data, and the inferred values can be used as a basis for determining which actions to perform. The learning processor  1530  may perform AI processing together with the learning processor of the AI server. The learning processor  1530  may include a memory integrated and/or implemented in the AI device  1500 . Alternatively, the learning processor  1530  may be implemented using the memory  1560 , an external memory directly coupled to the AI device  1500 , and/or a memory maintained in an external device. 
     The sensing part  1540  may acquire at least one of internal information of the AI device  1500 , environment information of the AI device  1500 , and/or the user information using various sensors. The sensors included in the sensing part  1540  may include a proximity sensor, an illuminance sensor, an acceleration sensor, a magnetic sensor, a gyro sensor, an inertial sensor, an RGB sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, an optical sensor, a microphone, a light detection and ranging (LIDAR), and/or a radar. 
     The output part  1550  may generate an output related to visual, auditory, tactile, etc. The output part  1550  may include a display unit for outputting visual information, a speaker for outputting auditory information, and/or a haptic module for outputting tactile information. 
     The memory  1560  may store data that supports various functions of the AI device  1500 . For example, the memory  1560  may store input data acquired by the input part  1520 , learning data, a learning model, a learning history, etc. 
     The processor  1570  may determine at least one executable operation of the AI device  1500  based on information determined and/or generated using a data analysis algorithm and/or a machine learning algorithm. The processor  1570  may then control the components of the AI device  1500  to perform the determined operation. The processor  1570  may request, retrieve, receive, and/or utilize data in the learning processor  1530  and/or the memory  1560 , and may control the components of the AI device  1500  to execute the predicted operation and/or the operation determined to be desirable among the at least one executable operation. The processor  1570  may generate a control signal for controlling the external device, and may transmit the generated control signal to the external device, when the external device needs to be linked to perform the determined operation. The processor  1570  may obtain the intention information for the user input and determine the user&#39;s requirements based on the obtained intention information. The processor  1570  may use at least one of a speech-to-text (STT) engine for converting speech input into a text string and/or a natural language processing (NLP) engine for acquiring intention information of a natural language, to obtain the intention information corresponding to the user input. At least one of the STT engine and/or the NLP engine may be configured as an ANN, at least a part of which is learned according to a machine learning algorithm. At least one of the STT engine and/or the NLP engine may be learned by the learning processor  1530  and/or learned by the learning processor of the AI server, and/or learned by their distributed processing. The processor  1570  may collect history information including the operation contents of the AI device  1500  and/or the user&#39;s feedback on the operation, etc. The processor  1570  may store the collected history information in the memory  1560  and/or the learning processor  1530 , and/or transmit to an external device such as the AI server. The collected history information can be used to update the learning model. The processor  1570  may control at least some of the components of AI device  1500  to drive an application program stored in memory  1560 . Furthermore, the processor  1570  may operate two or more of the components included in the AI device  1500  in combination with each other for driving the application program. 
       FIG. 16  shows an example of an AI system to which the technical features of the present disclosure can be applied. 
     Referring to  FIG. 16 , in the AI system, at least one of an AI server  1620 , a robot  1610   a , an autonomous vehicle  1610   b , an XR device  1610   c , a smartphone  1610   d  and/or a home appliance  1610   e  is connected to a cloud network  1600 . The robot  1610   a , the autonomous vehicle  1610   b , the XR device  1610   c , the smartphone  1610   d , and/or the home appliance  1610   e  to which the AI technology is applied may be referred to as AI devices  1610   a  to  1610   e.    
     The cloud network  1600  may refer to a network that forms part of a cloud computing infrastructure and/or resides in a cloud computing infrastructure. The cloud network  1600  may be configured using a 3G network, a 4G or LTE network, and/or a 5G network. That is, each of the devices  1610   a  to  1610   e  and  1620  consisting the AI system may be connected to each other through the cloud network  1600 . In particular, each of the devices  1610   a  to  1610   e  and  1620  may communicate with each other through a base station, but may directly communicate with each other without using a base station. 
     The AI server  1620  may include a server for performing AI processing and a server for performing operations on big data. The AI server  1620  is connected to at least one or more of AI devices constituting the AI system, i.e., the robot  1610   a , the autonomous vehicle  1610   b , the XR device  1610   c , the smartphone  1610   d  and/or the home appliance  1610   e  through the cloud network  1600 , and may assist at least some AI processing of the connected AI devices  1610   a  to  1610   e . The AI server  1620  can learn the ANN according to the machine learning algorithm on behalf of the AI devices  1610   a  to  1610   e , and can directly store the learning models and/or transmit them to the AI devices  1610   a  to  1610   e . The AI server  1620  may receive the input data from the AI devices  1610   a  to  1610   e , infer the result value with respect to the received input data using the learning model, generate a response and/or a control command based on the inferred result value, and transmit the generated data to the AI devices  1610   a  to  1610   e . Alternatively, the AI devices  1610   a  to  1610   e  may directly infer a result value for the input data using a learning model, and generate a response and/or a control command based on the inferred result value. 
     Various embodiments of the AI devices  1610   a  to  1610   e  to which the technical features of the present disclosure can be applied will be described. The AI devices  1610   a  to  1610   e  shown in  FIG. 16  can be seen as specific embodiments of the AI device  1500  shown in  FIG. 15 . 
     &lt;AI+Autonomous-driving/self-driving&gt; 
     The autonomous vehicle  1610   b  may be implemented as a mobile robot, a vehicle, an unmanned aerial vehicle, etc., to which AI technology is applied. The autonomous vehicle  1610   b  may include an autonomous driving control module for controlling the autonomous driving function, and the autonomous driving control module may refer to a software module and/or a chip implementing the software module. The autonomous driving control module may be included in the autonomous vehicle  1610   b  as a component of the autonomous vehicle  1610   b , but may be connected to the outside of the autonomous vehicle  1610   b  with separate hardware. The autonomous vehicle  1610   b  may acquire the state information of the autonomous vehicle  1610   b  using the sensor information acquired from various kinds of sensors and/or detect (recognize) the surrounding environment and/or the object, and/or generate map data, and/or determine a travel route and/or a travel plan, and/or determine an operation. Like the robot  1610   a , the autonomous vehicle  1610   b  can use the sensor information acquired from at least one sensor among the LIDAR, the radar, and/or the camera to determine the travel route and/or the travel plan. In particular, the autonomous vehicle  1610   b  can recognize an environment and/or an object for an area in which the field of view is obscured and/or over a certain distance by receiving sensor information from external devices, and/or receive the recognized information directly from external devices. 
     The autonomous vehicle  1610   b  can perform the above-described operations using a learning model composed of at least one ANN. For example, the autonomous vehicle  1610   b  can recognize the surrounding environment and/or the object using the learning model, and can determine the travel route using the recognized surrounding information and/or the object information. The learning model may be learned directly from the autonomous vehicle  1610   b  and/or learned from an external device such as the AI server  1600 . The autonomous vehicle  1610   b  can directly generate a result using the learning model and perform an operation. The autonomous vehicle  1610   b  may transmit sensor information to an external device such as the AI server  1620  and may receive the generated result and perform an operation. 
     The autonomous vehicle  1610   b  may determine the travel route and/or the travel plan using at least one of the map data, the object information detected from the sensor information and/or the object information acquired from the external device, and drive the autonomous vehicle  1610   b  according to the determined travel route and/or travel plan by controlling the driving unit. The map data may include object identification information on various objects arranged in a space (e.g. road) in which the autonomous vehicle  1610   b  moves. For example, the map data may include object identification information on fixed objects such as street lamps, rocks, and buildings, and/or on movable objects such as vehicles and pedestrians. The object identification information may include a name, a type, a distance, and/or a position, etc. The autonomous vehicle  1610   b  can perform the operation and/or run by controlling the driving unit based on the control/interaction of the user. The autonomous vehicle  1610   b  may acquire the intention information of the interaction due to the user&#39;s operation and/or voice utterance, determine the response based on the acquired intention information, and perform the operation. 
     The present disclosure can have various advantageous effects. 
     For example, the resource allocation for advanced V2X services can be realistic in case of MR-DC based use cases (e.g., EN-DC, NGEN-DC, NE-DC). 
     Advantageous effects which can be obtained through specific embodiments of the present disclosure are not limited to the advantageous effects listed above. For example, there may be a variety of technical effects that a person having ordinary skill in the related art can understand and/or derive from the present disclosure. Accordingly, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that may be understood or derived from the technical features of the present disclosure. 
     In view of the exemplary systems described herein, methodologies that may be implemented in accordance with the disclosed subject matter have been described with reference to several flow diagrams. While for purposed of simplicity, the methodologies are shown and described as a series of steps or blocks, it is to be understood and appreciated that the claimed subject matter is not limited by the order of the steps or blocks, as some steps may occur in different orders or concurrently with other steps from what is depicted and described herein. Moreover, one skilled in the art would understand that the steps illustrated in the flow diagram are not exclusive and other steps may be included or one or more of the steps in the example flow diagram may be deleted without affecting the scope of the present disclosure. 
     Claims in the present description can be combined in a various way. For instance, technical features in method claims of the present description can be combined to be implemented or performed in an apparatus, and technical features in apparatus claims can be combined to be implemented or performed in a method. Further, technical features in method claim(s) and apparatus claim(s) can be combined to be implemented or performed in an apparatus. Further, technical features in method claim(s) and apparatus claim(s) can be combined to be implemented or performed in a method. Other implementations are within the scope of the following claims.