Method and apparatus for data forwarding in a wireless network system

Abstract

A method and apparatus for data forwarding in a wireless network system is provided. A CU-CP of a RAN node transmits, to a CU-UP of the RAN node, a first message including (i) information requesting to perform indirect data forwarding, (ii) information related to a forwarding transport layer, and (iii) information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer. The CU-CP receives, from the CU-UP, a second message, in response to the first message, including information related to an allocated receiving transport layer.

Description

METHOD AND APPARATUS FOR DATA FORWARDING IN A WIRELESS NETWORK SYSTEM

[0001] The present disclosure relates to a method and apparatus for data forwarding in a wireless network system.

[0002] 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.

[0003] 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.

[0004] 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.

[0005] Discussions has been ongoing on how to optimize early data forwarding in CHO with NR-DC scenarios, so that NW (especially, the source side) can avoid duplicated data forwarding to the target nodes before the UE executes CHO with NR-DC. Especially, CHO can be requested for multiple T-MN nodes for the same UE where the same T-SN can be reached to prepare conditional configurations for the UE's SCG. In this case, data forwarding from the source side could happen over multiple paths towards the same T-SN. This can result in forwarding duplicated data for PDU sessions or DRBs established in T-SN, when admission results for CHO NR-DC requests from different T-MNs are identical.

[0006] In addition, support for indirect data forwarding has been also discussed where there are no direct paths available, i.e., when there is no direct path between S-SN and T-SN, between S-MN and T-SN, or between S-SN and T-MN. In such cases, a node in the middle (for example, S-MN or T-MN) should be able to decide indirect data forwarding support. If decided, then it needs to assign its own TNL (Transport Network Layer) address to receive the forwarded packets and relay them to the final destination accordingly.

[0007] However, such indirect data forwarding has been assumed to be supported implicitly in 3GPP, leaving up to implementation. In case of a monolithic gNB, implementations sufficed because the gNB could handle all the control and user plane functionalities. On the other hand, it has been left unspecified when a gNB is split into control plane entity (gNB-CU-CP, a.k.a. CU-CP) and user-plane entity (gNB-CU-UP, a.k.a. CU-UP). In this case, it is unclear how indirect data forwarding can be supported in the CU-UP entity dedicated to handling user plane functionalities.

[0008] Moreover, a node in the middle (e.g. S-MN or T-MN) needs to know whether PDU session or DRBs subject for data forwarding during HO or DC is terminated in MN or SN, in order to properly decide indirect forwarding support based on path availabilities. For example, T-MN needs to know whether a PDU session decided to be terminated in T-SN was originally terminated in S-MN or S-SN before HO is triggered. If terminated in S-SN but there is no direct path between S-SN and T-SN (but direct path exists between S-SN and T-MN), then T-MN can decide to perform indirect forwarding for this PDU session. If terminated in S-MN but no direct path between S-MN and T-SN, then T-MN can decide to perform indirect forwarding for this PDU session. On the other hand, if direct path exists from where a PDU session (decided to be terminated in T-SN) was originally located in the source side to T-SN, then direct forwarding is possible and there is no need for T-MN to perform indirect data forwarding for this PDU session: it can simply forward the destination TNL address to S-MN during HO preparation.

[0009] The similar logic also applies to S-MN. The S-MN also needs to know whether a PDU session subject for data forwarding is established in MN or SN in the target side during HO preparation. If established in T-SN, but originally it was hosted in S-SN and there is no direct path between S-SN and T-SN, then S-MN can decide to perform indirect forwarding for this PDU session. The same applies if established in T-MN, but originally it was hosted in S-SN and no direct path between S-SN and T-MN. On the other hand, if there exists direct path between S-SN and T-MN, then direct forwarding is possible and there is no reason for S-MN to perform indirect data forwarding for this PDU session.

[0010] In light of these considerations, information about whether a PDU session or DRB subject for data forwarding is (or was) terminated in MN or SN in the target side (or source side) is crucial for S-MN (or T-MN) to make informed decisions on indirect forwarding. The path availabilities are not enough. While it is assumed that T-MN can ascertain whether a PDU session or DRB requested to setup during HO was originally hosted in S-MN or S-SN via the inter-node RRC container ofHandoverPreparation, it is still unclear on how S-MN can know whether a PDU session or DRB subject for data forwarding is hosted in T-MN or T-SN during HO preparation.

[0011] Therefore, studies for data forwarding in a wireless network system are required.

[0012] In an aspect, a method performed by a Central Unit (CU)-Control Plane (CP) of a radio access network (RAN) node in a wireless communication system is provided. The method comprises: transmitting, to a CU-User Plane (UP) of the RAN node, a first message including (i) information requesting to perform indirect data forwarding, (ii) information related to a forwarding transport layer, and (iii) information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer; and receiving, from the CU-UP, a second message, in response to the first message, including information related to an allocated receiving transport layer.

[0013] In another aspect, an apparatus for implementing the above method is provided.

[0014] The present disclosure can have various advantageous effects.

[0015] According to some embodiments of the present disclosure, the network could efficiently support for indirect data forwarding and / or direct data forwarding during Handover (HO) or Dual Connectivity (DC).

[0016] For example, embodiments described in this present disclosure enables network nodes to support indirect data forwarding during HO or DC procedures when there are no direct paths available between the source and target entities, and also enables indirect data forwarding in Central Unit (CU)-User Plane (UP) entities (in short, CU-UP) dedicated to handle all the user plane functionalities.

[0017] For example, when there is no direct path between the source and target nodes, network nodes can efficiently support indirect data forwarding and / or direct data forwarding during HO or DC procedures.

[0018] For example, the CU-UP entity can efficiently perform indirect data forwarding and / or direct data forwarding.

[0019] 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.

[0020] FIG. 1 shows an example of a communication system to which implementations of the present disclosure is applied.

[0021] FIG. 2 shows an example of wireless devices to which implementations of the present disclosure is applied.

[0022] FIG. 3 shows an example of a wireless device to which implementations of the present disclosure is applied.

[0023] FIG. 4 shows an example of UE to which implementations of the present disclosure is applied.

[0024] FIGS. 5 and 6 show an example of protocol stacks in a 3GPP based wireless communication system to which implementations of the present disclosure is applied.

[0025] FIG. 7 shows an example of the overall architecture of an NG-RAN to which technical features of the present disclosure can be applied.

[0026] FIG. 8 shows an interface protocol structure for E1 interface to which technical features of the present disclosure can be applied.

[0027] FIGs. 9a and 9b shows an example signalling flow for inter-MN handover with / without MN initiated SN change procedure.

[0028] FIG. 10 shows an example of a successful operation for S-NG-RAN node Addition Preparation procedure.

[0029] FIG. 11 shows an example of an unsuccessful operation for S-NG-RAN node Addition Preparation procedure.

[0030] FIG. 12 shows an example of a method for data forwarding in a wireless network system, according to some embodiments of the present disclosure.

[0031] FIG. 13 shows a flow chart for indirect data forwarding support in T-MN.

[0032] FIG. 14 shows a flow chart for indirect data forwarding support in S-MN.

[0033] FIG. 15 shows a flow chart for indirect data forwarding termination from CU-UP.

[0034] FIG. 16 shows a flow chart for resource pooling for indirect data forwarding support in CU-UP.

[0035] FIG. 17 shows an example of a method for indirect data forwarding in a wireless network system, according to some embodiments of the present disclosure.

[0036] The following techniques, apparatuses, and systems may be applied to a variety of wireless multiple access systems. Examples of the multiple access systems include a code division multiple access (CDMA) system, a frequency division multiple access (FDMA) system, a time division multiple access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, a single carrier frequency division multiple access (SC-FDMA) system, and a multicarrier frequency division multiple access (MC-FDMA) system. CDMA may be embodied through radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be embodied through radio technology such as global system for mobile communications (GSM), general packet radio service (GPRS), or enhanced data rates for GSM evolution (EDGE). OFDMA may be embodied through radio technology such as institute of electrical and electronics engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or evolved UTRA (E-UTRA). UTRA is a 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. 3GPP LTE employs OFDMA in DL and SC-FDMA in UL. Evolution of 3GPP LTE includes LTE-A (advanced), LTE-A Pro, and / or 5G NR (new radio).

[0037] For convenience of description, implementations of the present disclosure are mainly described in regards to a 3GPP based wireless communication system. However, the technical features of the present disclosure are not limited thereto. For example, although the following detailed description is given based on a mobile communication system corresponding to a 3GPP based wireless communication system, aspects of the present disclosure that are not limited to 3GPP based wireless communication system are applicable to other mobile communication systems.

[0038] For terms and technologies which are not specifically described among the terms of and technologies employed in the present disclosure, the wireless communication standard documents published before the present disclosure may be referenced.

[0039] In the present disclosure, "A or B" may mean "only A", "only B", or "both A and B". In other words, "A or B" in the present disclosure may be interpreted as "A and / or B". For example, "A, B or C" in the present disclosure may mean "only A", "only B", "only C", or "any combination of A, B and C".

[0040] In the present disclosure, slash ( / ) or comma (,) may mean "and / or". For example, "A / B" may mean "A and / or B". Accordingly, "A / B" may mean "only A", "only B", or "both A and B". For example, "A, B, C" may mean "A, B or C".

[0041] In the present disclosure, "at least one of A and B" may mean "only A", "only B" or "both A and B". In addition, the expression "at least one of A or B" or "at least one of A and / or B" in the present disclosure may be interpreted as same as "at least one of A and B".

[0042] In addition, in the present disclosure, "at least one of A, B and C" may mean "only A", "only B", "only C", or "any combination of A, B and C". In addition, "at least one of A, B or C" or "at least one of A, B and / or C" may mean "at least one of A, B and C".

[0043] Also, parentheses used in the present disclosure may mean "for example". In detail, when it is shown as "control information (PDCCH)", "PDCCH" may be proposed as an example of "control information". In other words, "control information" in the present disclosure is not limited to "PDCCH", and "PDCCH" may be proposed as an example of "control information". In addition, even when shown as "control information (i.e., PDCCH)", "PDCCH" may be proposed as an example of "control information".

[0044] Technical features that are separately described in one drawing in the present disclosure may be implemented separately or simultaneously.

[0045] Although not limited thereto, various descriptions, functions, procedures, suggestions, methods and / or operational flowcharts of the present disclosure disclosed herein can be applied to various fields requiring wireless communication and / or connection (e.g., 5G) between devices.

[0046] Hereinafter, the present disclosure will be described in more detail with reference to drawings. The same reference numerals in the following drawings and / or descriptions may refer to the same and / or corresponding hardware blocks, software blocks, and / or functional blocks unless otherwise indicated.

[0047] FIG. 1 shows an example of a communication system to which implementations of the present disclosure is applied.

[0048] 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.

[0049] Three main requirement categories for 5G include (1) a category of enhanced mobile broadband (eMBB), (2) a category of massive machine type communication (mMTC), and (3) a category of ultra-reliable and low latency communications (URLLC).

[0050] Partial use cases may require a plurality of categories for optimization and other use cases may focus only upon one key performance indicator (KPI). 5G supports such various use cases using a flexible and reliable method.

[0051] eMBB far surpasses basic mobile Internet access and covers abundant bidirectional work and media and entertainment applications in cloud and augmented reality. Data is one of 5G core motive forces and, in a 5G era, a dedicated voice service may not be provided for the first time. In 5G, it is expected that voice will be simply processed as an application program using data connection provided by a communication system. Main causes for increased traffic volume are due to an increase in the size of content and an increase in the number of applications requiring high data transmission rate. A streaming service (of audio and video), conversational video, and mobile Internet access will be more widely used as more devices are connected to the Internet. These many application programs require connectivity of an always turned-on state in order to push real-time information and alarm for users. Cloud storage and applications are rapidly increasing in a mobile communication platform and may be applied to both work and entertainment. The cloud storage is a special use case which accelerates growth of uplink data transmission rate. 5G is also used for remote work of cloud. When a tactile interface is used, 5G demands much lower end-to-end latency to maintain user good experience. Entertainment, for example, cloud gaming and video streaming, is another core element which increases demand for mobile broadband capability. Entertainment is essential for a smartphone and a tablet in any place including high mobility environments such as a train, a vehicle, and an airplane. Other use cases are augmented reality for entertainment and information search. In this case, the augmented reality requires very low latency and instantaneous data volume.

[0052] In addition, one of the most expected 5G use cases relates a function capable of smoothly connecting embedded sensors in all fields, i.e., mMTC. It is expected that the number of potential Internet-of-things (IoT) devices will reach 204 hundred million up to the year of 2020. An industrial IoT is one of categories of performing a main role enabling a smart city, asset tracking, smart utility, agriculture, and security infrastructure through 5G.

[0053] URLLC includes a new service that will change industry through remote control of main infrastructure and an ultra-reliable / available low-latency link such as a self-driving vehicle. A level of reliability and latency is essential to control a smart grid, automatize industry, achieve robotics, and control and adjust a drone.

[0054] 5G is a means of providing streaming evaluated as a few hundred megabits per second to gigabits per second and may complement fiber-to-the-home (FTTH) and cable-based broadband (or DOCSIS). Such fast speed is needed to deliver TV in resolution of 4K or more (6K, 8K, and more), as well as virtual reality and augmented reality. Virtual reality (VR) and augmented reality (AR) applications include almost immersive sports games. A specific application program may require a special network configuration. For example, for VR games, gaming companies need to incorporate a core server into an edge network server of a network operator in order to minimize latency.

[0055] Automotive is expected to be a new important motivated force in 5G together with many use cases for mobile communication for vehicles. For example, entertainment for passengers requires high simultaneous capacity and mobile broadband with high mobility. This is because future users continue to expect connection of high quality regardless of their locations and speeds. Another use case of an automotive field is an AR dashboard. The AR dashboard causes a driver to identify an object in the dark in addition to an object seen from a front window and displays a distance from the object and a movement of the object by overlapping information talking to the driver. In the future, a wireless module enables communication between vehicles, information exchange between a vehicle and supporting infrastructure, and information exchange between a vehicle and other connected devices (e.g., devices accompanied by a pedestrian). A safety system guides alternative courses of a behavior so that a driver may drive more safely drive, thereby lowering the danger of an accident. The next stage will be a remotely controlled or self-driven vehicle. This requires very high reliability and very fast communication between different self-driven vehicles and between a vehicle and infrastructure. In the future, a self-driven vehicle will perform all driving activities and a driver will focus only upon abnormal traffic that the vehicle cannot identify. Technical requirements of a self-driven vehicle demand ultra-low latency and ultra-high reliability so that traffic safety is increased to a level that cannot be achieved by human being.

[0056] A smart city and a smart home / building mentioned as a smart society will be embedded in a high-density wireless sensor network. A distributed network of an intelligent sensor will identify conditions for costs and energy-efficient maintenance of a city or a home. Similar configurations may be performed for respective households. All of temperature sensors, window and heating controllers, burglar alarms, and home appliances are wirelessly connected. Many of these sensors are typically low in data transmission rate, power, and cost. However, real-time HD video may be demanded by a specific type of device to perform monitoring.

[0057] Consumption and distribution of energy including heat or gas is distributed at a higher level so that automated control of the distribution sensor network is demanded. The smart grid collects information and connects the sensors to each other using digital information and communication technology so as to act according to the collected information. Since this information may include behaviors of a supply company and a consumer, the smart grid may improve distribution of fuels such as electricity by a method having efficiency, reliability, economic feasibility, production sustainability, and automation. The smart grid may also be regarded as another sensor network having low latency.

[0058] Mission critical application (e.g., e-health) is one of 5G use scenarios. A health part contains many application programs capable of enjoying benefit of mobile communication. A communication system may support remote treatment that provides clinical treatment in a faraway place. Remote treatment may aid in reducing a barrier against distance and improve access to medical services that cannot be continuously available in a faraway rural area. Remote treatment is also used to perform important treatment and save lives in an emergency situation. The wireless sensor network based on mobile communication may provide remote monitoring and sensors for parameters such as heart rate and blood pressure.

[0059] Wireless and mobile communication gradually becomes important in the field of an industrial application. Wiring is high in installation and maintenance cost. Therefore, a possibility of replacing a cable with reconstructible wireless links is an attractive opportunity in many industrial fields. However, in order to achieve this replacement, it is necessary for wireless connection to be established with latency, reliability, and capacity similar to those of the cable and management of wireless connection needs to be simplified. Low latency and a very low error probability are new requirements when connection to 5G is needed.

[0060] Logistics and freight tracking are important use cases for mobile communication that enables inventory and package tracking anywhere using a location-based information system. The use cases of logistics and freight typically demand low data rate but require location information with a wide range and reliability.

[0061] Referring to FIG. 1, the communication system 1 includes wireless devices 100a to 100f, base stations (BSs) 200, and a network 300. Although FIG. 1 illustrates a 5G network as an example of the network of the communication system 1, the implementations of the present disclosure are not limited to the 5G system, and can be applied to the future communication system beyond the 5G system.

[0062] The BSs 200 and the network 300 may be implemented as wireless devices and a specific wireless device may operate as a BS / network node with respect to other wireless devices.

[0063] The wireless devices 100a to 100f represent devices performing communication using radio access technology (RAT) (e.g., 5G new RAT (NR)) or LTE) and may be referred to as communication / radio / 5G devices. The wireless devices 100a to 100f may include, without being limited to, a robot 100a, vehicles 100b-1 and 100b-2, an extended reality (XR) device 100c, a hand-held device 100d, a home appliance 100e, an IoT device 100f, and an artificial intelligence (AI) device / server 400. For example, the vehicles may include a vehicle having a wireless communication function, an autonomous driving vehicle, and a vehicle capable of performing communication between vehicles. The vehicles may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device may include an AR / VR / Mixed Reality (MR) device and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) mounted in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, etc. The hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or a smartglasses), and a computer (e.g., a notebook). The home appliance may include a TV, a refrigerator, and a washing machine. The IoT device may include a sensor and a smartmeter.

[0064] In the present disclosure, the wireless devices 100a to 100f may be called user equipments (UEs). A UE may include, for example, a cellular phone, a smartphone, a laptop computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a slate personal computer (PC), a tablet PC, an ultrabook, a vehicle, a vehicle having an autonomous traveling function, a connected car, an 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 FinTech device (or a financial device), a security device, a weather / environment device, a device related to a 5G service, or a device related to a fourth industrial revolution field.

[0065] The UAV may be, for example, an aircraft aviated by a wireless control signal without a human being onboard.

[0066] The VR device may include, for example, a device for implementing an object or a background of the virtual world. The AR device may include, for example, a device implemented by connecting an object or a background of the virtual world to an object or a background of the real world. The MR device may include, for example, a device implemented by merging an object or a background of the virtual world into an object or a background of the real world. The hologram device may include, for example, a device for implementing a stereoscopic image of 360 degrees by recording and reproducing stereoscopic information, using an interference phenomenon of light generated when two laser lights called holography meet.

[0067] The public safety device may include, for example, an image relay device or an image device that is wearable on the body of a user.

[0068] The MTC device and the IoT device may be, for example, devices that do not require direct human intervention or manipulation. For example, the MTC device and the IoT device may include smartmeters, vending machines, thermometers, smartbulbs, door locks, or various sensors.

[0069] The medical device may be, for example, a device used for the purpose of diagnosing, treating, relieving, curing, or preventing disease. For example, the medical device may be a device used for the purpose of diagnosing, treating, relieving, or correcting injury or impairment. For example, the medical device may be a device used for the purpose of inspecting, replacing, or modifying a structure or a function. For example, the medical device may be a device used for the purpose of adjusting pregnancy. For example, the medical device may include a device for treatment, a device for operation, a device for (in vitro) diagnosis, a hearing aid, or a device for procedure.

[0070] The security device may be, for example, a device installed to prevent a danger that may arise and to maintain safety. For example, the security device may be a camera, a closed-circuit TV (CCTV), a recorder, or a black box.

[0071] The FinTech device may be, for example, a device capable of providing a financial service such as mobile payment. For example, the FinTech device may include a payment device or a point of sales (POS) system.

[0072] The weather / environment device may include, for example, a device for monitoring or predicting a weather / environment.

[0073] The wireless devices 100a to 100f may be connected to the network 300 via the BSs 200. An AI technology may be applied to the wireless devices 100a to 100f and the wireless devices 100a to 100f may be connected to the AI server 400 via the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, and a beyond-5G network. Although the wireless devices 100a to 100f may communicate with each other through the BSs 200 / network 300, the wireless devices 100a to 100f may perform direct communication (e.g., sidelink communication) with each other without passing through the BSs 200 / network 300. For example, the vehicles 100b-1 and 100b-2 may perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). The IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0074] Wireless communication / connections 150a, 150b and 150c may be established between the wireless devices 100a to 100f and / or between wireless device 100a to 100f and BS 200 and / or between BSs 200. Herein, the wireless communication / connections may be established through various RATs (e.g., 5G NR) such as uplink / downlink communication 150a, sidelink communication (or device-to-device (D2D) communication) 150b, inter-base station communication 150c (e.g., relay, integrated access and backhaul (IAB)), etc. The wireless devices 100a to 100f and the BSs 200 / the wireless devices 100a to 100f may transmit / receive radio signals to / from each other through the wireless communication / connections 150a, 150b and 150c. For example, the wireless communication / connections 150a, 150b and 150c may transmit / receive signals through various physical channels. To this end, at least a part of various configuration information configuring processes, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, and resource mapping / de-mapping), and resource allocating processes, for transmitting / receiving radio signals, may be performed based on the various proposals of the present disclosure.

[0075] AI refers to the field of studying artificial intelligence or the methodology that can create it, and machine learning refers to the field of defining various problems addressed in the field of AI and the field of methodology to solve them. Machine learning is also defined as an algorithm that increases the performance of a task through steady experience on a task.

[0076] Robot means a machine that automatically processes or operates a given task by its own ability. In particular, robots with the ability to recognize the environment and make self-determination to perform actions can be called intelligent robots. Robots can be classified as industrial, medical, home, military, etc., depending on the purpose or area of use. The robot can perform a variety of physical operations, such as moving the robot joints with actuators or motors. The movable robot also includes wheels, brakes, propellers, etc., on the drive, allowing it to drive on the ground or fly in the air.

[0077] Autonomous driving means a technology that drives on its own, and autonomous vehicles mean vehicles that drive without user's control or with minimal user's control. For example, autonomous driving may include maintaining lanes in motion, automatically adjusting speed such as adaptive cruise control, automatic driving along a set route, and automatically setting a route when a destination is set. The vehicle covers vehicles equipped with internal combustion engines, hybrid vehicles equipped with internal combustion engines and electric motors, and electric vehicles equipped with electric motors, and may include trains, motorcycles, etc., as well as cars. Autonomous vehicles can be seen as robots with autonomous driving functions.

[0078] Extended reality is collectively referred to as VR, AR, and MR. VR technology provides objects and backgrounds of real world only through computer graphic (CG) images. AR technology provides a virtual CG image on top of a real object image. MR technology is a CG technology that combines and combines virtual objects into the real world. MR technology is similar to AR technology in that they show real and virtual objects together. However, there is a difference in that in AR technology, virtual objects are used as complementary forms to real objects, while in MR technology, virtual objects and real objects are used as equal personalities.

[0079] NR supports multiples numerologies (and / or multiple subcarrier spacings (SCS)) to support various 5G services. For example, if SCS is 15 kHz, wide area can be supported in traditional cellular bands, and if SCS is 30 kHz / 60 kHz, dense-urban, lower latency, and wider carrier bandwidth can be supported. If SCS is 60 kHz or higher, bandwidths greater than 24.25 GHz can be supported to overcome phase noise.

[0080] 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).

[0081] Frequency Range designationCorresponding frequency rangeSubcarrier SpacingFR1450MHz - 6000MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0082] 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 410MHz to 7125MHz as shown in Table 2 below. That is, FR1 may include a frequency band of 6GHz (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).

[0083] Frequency Range designationCorresponding frequency rangeSubcarrier SpacingFR1410MHz - 7125MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0084] Here, the radio communication technologies implemented in the wireless devices in the present disclosure may include narrowband internet-of-things (NB-IoT) technology for low-power communication as well as LTE, NR and 6G. For example, NB-IoT technology may be an example of low power wide area network (LPWAN) technology, may be implemented in specifications such as LTE Cat NB1 and / or LTE Cat NB2, and may not be limited to the above-mentioned names. Additionally and / or alternatively, the radio communication technologies implemented in the wireless devices in the present disclosure may communicate based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology and be called by various names such as enhanced machine type communication (eMTC). For example, LTE-M technology may be implemented in at least one of the various specifications, such as 1) LTE Cat 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-bandwidth limited (non-BL), 5) LTE-MTC, 6) LTE Machine Type Communication, and / or 7) LTE M, and may not be limited to the above-mentioned names. Additionally and / or alternatively, the radio communication technologies implemented in the wireless devices in the present disclosure may include at least one of ZigBee, Bluetooth, and / or LPWAN which take into account low-power communication, and may not be limited to the above-mentioned names. For example, ZigBee technology may generate personal area networks (PANs) associated with small / low-power digital communication based on various specifications such as IEEE 802.15.4 and may be called various names.

[0085] FIG. 2 shows an example of wireless devices to which implementations of the present disclosure is applied.

[0086] Referring to FIG. 2, a first wireless device 100 and a second wireless device 200 may transmit / receive radio signals to / from an external device through a variety of RATs (e.g., LTE and NR).

[0087] In FIG. 2, {the first wireless device 100 and the second wireless device 200} may correspond to at least one of {the wireless device 100a to 100f and the BS 200}, {the wireless device 100a to 100f and the wireless device 100a to 100f} and / or {the BS 200 and the BS 200} of FIG. 1.

[0088] The first wireless device 100 may include at least one transceiver, such as a transceiver 106, at least one processing chip, such as a processing chip 101, and / or one or more antennas 108.

[0089] The processing chip 101 may include at least one processor, such a processor 102, and at least one memory, such as a memory 104. It is exemplarily shown in FIG. 2 that the memory 104 is included in the processing chip 101. Additional and / or alternatively, the memory 104 may be placed outside of the processing chip 101.

[0090] The processor 102 may control the memory 104 and / or the transceiver 106 and may be configured to implement the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts described in the present disclosure. For example, the processor 102 may process information within the memory 104 to generate first information / signals and then transmit radio signals including the first information / signals through the transceiver 106. The processor 102 may receive radio signals including second information / signals through the transceiver 106 and then store information obtained by processing the second information / signals in the memory 104.

[0091] The memory 104 may be operably connectable to the processor 102. The memory 104 may store various types of information and / or instructions. The memory 104 may store a software code 105 which implements instructions that, when executed by the processor 102, perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. For example, the software code 105 may implement instructions that, when executed by the processor 102, perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. For example, the software code 105 may control the processor 102 to perform one or more protocols. For example, the software code 105 may control the processor 102 to perform one or more layers of the radio interface protocol.

[0092] Herein, the processor 102 and the memory 104 may be a part of a communication modem / circuit / chip designed to implement RAT (e.g., LTE or NR). The transceiver 106 may be connected to the processor 102 and transmit and / or receive radio signals through one or more antennas 108. Each of the transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be interchangeably used with radio frequency (RF) unit(s). In the present disclosure, the first wireless device 100 may represent a communication modem / circuit / chip.

[0093] The second wireless device 200 may include at least one transceiver, such as a transceiver 206, at least one processing chip, such as a processing chip 201, and / or one or more antennas 208.

[0094] The processing chip 201 may include at least one processor, such a processor 202, and at least one memory, such as a memory 204. It is exemplarily shown in FIG. 2 that the memory 204 is included in the processing chip 201. Additional and / or alternatively, the memory 204 may be placed outside of the processing chip 201.

[0095] The processor 202 may control the memory 204 and / or the transceiver 206 and may be configured to implement the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts described in the present disclosure. For example, the processor 202 may process information within the memory 204 to generate third information / signals and then transmit radio signals including the third information / signals through the transceiver 206. The processor 202 may receive radio signals including fourth information / signals through the transceiver 106 and then store information obtained by processing the fourth information / signals in the memory 204.

[0096] The memory 204 may be operably connectable to the processor 202. The memory 204 may store various types of information and / or instructions. The memory 204 may store a software code 205 which implements instructions that, when executed by the processor 202, perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. For example, the software code 205 may implement instructions that, when executed by the processor 202, perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. For example, the software code 205 may control the processor 202 to perform one or more protocols. For example, the software code 205 may control the processor 202 to perform one or more layers of the radio interface protocol.

[0097] Herein, the processor 202 and the memory 204 may be a part of a communication modem / circuit / chip designed to implement RAT (e.g., LTE or NR). The transceiver 206 may be connected to the processor 202 and transmit and / or receive radio signals through one or more antennas 208. Each of the transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be interchangeably used with RF unit. In the present disclosure, the second wireless device 200 may represent a communication modem / circuit / chip.

[0098] Hereinafter, hardware elements of the wireless devices 100 and 200 will be described more specifically. One or more protocol layers may be implemented by, without being limited to, one or more processors 102 and 202. For example, the one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as physical (PHY) layer, media access control (MAC) layer, radio link control (RLC) layer, packet data convergence protocol (PDCP) layer, radio resource control (RRC) layer, and service data adaptation protocol (SDAP) layer). The one or more processors 102 and 202 may generate one or more protocol data units (PDUs) and / or one or more service data unit (SDUs) according to the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. The one or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. The one or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure and provide the generated signals to the one or more transceivers 106 and 206. The one or more processors 102 and 202 may receive the signals (e.g., baseband signals) from the one or more transceivers 106 and 206 and acquire the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure.

[0099] The one or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. As an example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in the one or more processors 102 and 202. The descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure may be implemented using firmware or software and the firmware or software may be configured to include the modules, procedures, or functions. Firmware or software configured to perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure may be included in the one or more processors 102 and 202 or stored in the one or more memories 104 and 204 so as to be driven by the one or more processors 102 and 202. The descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure may be implemented using firmware or software in the form of code, commands, and / or a set of commands.

[0100] The one or more memories 104 and 204 may be connected to the one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, code, instructions, and / or commands. The one or more memories 104 and 204 may be configured by read-only memories (ROMs), random access memories (RAMs), electrically erasable programmable read-only memories (EPROMs), flash memories, hard drives, registers, cash memories, computer-readable storage media, and / or combinations thereof. The one or more memories 104 and 204 may be located at the interior and / or exterior of the one or more processors 102 and 202. The one or more memories 104 and 204 may be connected to the one or more processors 102 and 202 through various technologies such as wired or wireless connection.

[0101] The one or more transceivers 106 and 206 may transmit user data, control information, and / or radio signals / channels, mentioned in the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure, to one or more other devices. The one or more transceivers 106 and 206 may receive user data, control information, and / or radio signals / channels, mentioned in the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure, from one or more other devices. For example, the one or more transceivers 106 and 206 may be connected to the one or more processors 102 and 202 and transmit and receive radio signals. For example, the one or more processors 102 and 202 may perform control so that the one or more transceivers 106 and 206 may transmit user data, control information, or radio signals to one or more other devices. The one or more processors 102 and 202 may perform control so that the one or more transceivers 106 and 206 may receive user data, control information, or radio signals from one or more other devices.

[0102] The one or more transceivers 106 and 206 may be connected to the one or more antennas 108 and 208 and the one or more transceivers 106 and 206 may be configured to transmit and receive user data, control information, and / or radio signals / channels, mentioned in the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure, through the one or more antennas 108 and 208. In the present disclosure, the one or more antennas 108 and 208 may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports).

[0103] The one or more transceivers 106 and 206 may convert received user data, control information, radio signals / channels, etc., from RF band signals into baseband signals in order to process received user data, control information, radio signals / channels, etc., using the one or more processors 102 and 202. The one or more transceivers 106 and 206 may convert the user data, control information, radio signals / channels, etc., processed using the one or more processors 102 and 202 from the base band signals into the RF band signals. To this end, the one or more transceivers 106 and 206 may include (analog) oscillators and / or filters. For example, the one or more transceivers 106 and 206 can up-convert OFDM baseband signals to OFDM signals by their (analog) oscillators and / or filters under the control of the one or more processors 102 and 202 and transmit the up-converted OFDM signals at the carrier frequency. The one or more transceivers 106 and 206 may receive OFDM signals at a carrier frequency and down-convert the OFDM signals into OFDM baseband signals by their (analog) oscillators and / or filters under the control of the one or more processors 102 and 202.

[0104] In the implementations of the present disclosure, a UE may operate as a transmitting device in uplink (UL) and as a receiving device in downlink (DL). In the implementations of the present disclosure, a BS may operate as a receiving device in UL and as a transmitting device in DL. Hereinafter, for convenience of description, it is mainly assumed that the first wireless device 100 acts as the UE, and the second wireless device 200 acts as the BS. For example, the processor(s) 102 connected to, mounted on or launched in the first wireless device 100 may be configured to perform the UE behavior according to an implementation of the present disclosure or control the transceiver(s) 106 to perform the UE behavior according to an implementation of the present disclosure. The processor(s) 202 connected to, mounted on or launched in the second wireless device 200 may be configured to perform the BS behavior according to an implementation of the present disclosure or control the transceiver(s) 206 to perform the BS behavior according to an implementation of the present disclosure.

[0105] In the present disclosure, a BS is also referred to as a node B (NB), an eNode B (eNB), or a gNB.

[0106] FIG. 3 shows an example of a wireless device to which implementations of the present disclosure is applied.

[0107] The wireless device may be implemented in various forms according to a use-case / service (refer to FIG. 1).

[0108] Referring to FIG. 3, wireless devices 100 and 200 may correspond to the wireless devices 100 and 200 of FIG. 2 and may be configured by various elements, components, units / portions, and / or modules. For example, each of the wireless devices 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130, and additional components 140. The communication unit 110 may include a communication circuit 112 and transceiver(s) 114. For example, the communication circuit 112 may include the one or more processors 102 and 202 of FIG. 2 and / or the one or more memories 104 and 204 of FIG. 2. For example, the transceiver(s) 114 may include the one or more transceivers 106 and 206 of FIG. 2 and / or the one or more antennas 108 and 208 of FIG. 2. The control unit 120 is electrically connected to the communication unit 110, the memory unit 130, and the additional components 140 and controls overall operation of each of the wireless devices 100 and 200. For example, the control unit 120 may control an electric / mechanical operation of each of the wireless devices 100 and 200 based on programs / code / commands / information stored in the memory unit 130. The control unit 120 may transmit the information stored in the memory unit 130 to the exterior (e.g., other communication devices) via the communication unit 110 through a wireless / wired interface or store, in the memory unit 130, information received through the wireless / wired interface from the exterior (e.g., other communication devices) via the communication unit 110.

[0109] The additional components 140 may be variously configured according to types of the wireless devices 100 and 200. For example, the additional components 140 may include at least one of a power unit / battery, input / output (I / O) unit (e.g., audio I / O port, video I / O port), a driving unit, and a computing unit. The wireless devices 100 and 200 may be implemented in the form of, without being limited to, the robot (100a of FIG. 1), the vehicles (100b-1 and 100b-2 of FIG. 1), the XR device (100c of FIG. 1), the hand-held device (100d of FIG. 1), the home appliance (100e of FIG. 1), the IoT device (100f of FIG. 1), a digital broadcast terminal, a hologram device, a public safety device, an MTC device, a medicine device, a FinTech device (or a finance device), a security device, a climate / environment device, the AI server / device (400 of FIG. 1), the BSs (200 of FIG. 1), a network node, etc. The wireless devices 100 and 200 may be used in a mobile or fixed place according to a use-example / service.

[0110] In FIG. 3, the entirety of the various elements, components, units / portions, and / or modules in the wireless devices 100 and 200 may be connected to each other through a wired interface or at least a part thereof may be wirelessly connected through the communication unit 110. For example, in each of the wireless devices 100 and 200, the control unit 120 and the communication unit 110 may be connected by wire and the control unit 120 and first units (e.g., 130 and 140) may be wirelessly connected through the communication unit 110. Each element, component, unit / portion, and / or module within the wireless devices 100 and 200 may further include one or more elements. For example, the control unit 120 may be configured by a set of one or more processors. As an example, the control unit 120 may be configured by a set of a communication control processor, an application processor (AP), an electronic control unit (ECU), a graphical processing unit, and a memory control processor. As another example, the memory unit 130 may be configured by a RAM, a DRAM, a ROM, a flash memory, a volatile memory, a non-volatile memory, and / or a combination thereof.

[0111] FIG. 4 shows an example of UE to which implementations of the present disclosure is applied.

[0112] Referring to FIG. 4, a UE 100 may correspond to the first wireless device 100 of FIG. 2 and / or the wireless device 100 or 200 of FIG. 3.

[0113] A UE 100 includes a processor 102, a memory 104, a transceiver 106, one or more antennas 108, a power management module 110, a battery 112, a display 114, a keypad 116, a subscriber identification module (SIM) card 118, a speaker 120, and a microphone 122.

[0114] The processor 102 may be configured to implement the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. The processor 102 may be configured to control one or more other components of the UE 100 to implement the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. Layers of the radio interface protocol may be implemented in the processor 102. The processor 102 may include ASIC, other chipset, logic circuit and / or data processing device. The processor 102 may be an application processor. The processor 102 may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), a modem (modulator and demodulator). An example of the processor 102 may be found in SNAPDRAGONTMseries of processors made by Qualcomm®, EXYNOSTMseries of processors made by Samsung®, A series of processors made by Apple®, HELIOTMseries of processors made by MediaTek®, ATOMTMseries of processors made by Intel®or a corresponding next generation processor.

[0115] The memory 104 is operatively coupled with the processor 102 and stores a variety of information to operate the processor 102. The memory 104 may include ROM, RAM, flash memory, memory card, storage medium and / or other storage device. When the embodiments are implemented in software, the techniques described herein can be implemented with modules (e.g., procedures, functions, etc.) that perform the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. The modules can be stored in the memory 104 and executed by the processor 102. The memory 104 can be implemented within the processor 102 or external to the processor 102 in which case those can be communicatively coupled to the processor 102 via various means as is known in the art.

[0116] The transceiver 106 is operatively coupled with the processor 102, and transmits and / or receives a radio signal. The transceiver 106 includes a transmitter and a receiver. The transceiver 106 may include baseband circuitry to process radio frequency signals. The transceiver 106 controls the one or more antennas 108 to transmit and / or receive a radio signal.

[0117] The power management module 110 manages power for the processor 102 and / or the transceiver 106. The battery 112 supplies power to the power management module 110.

[0118] The display 114 outputs results processed by the processor 102. The keypad 116 receives inputs to be used by the processor 102. The keypad 116 may be shown on the display 114.

[0119] The SIM card 118 is an　integrated circuit　that is intended to　securely store the　international mobile subscriber identity　(IMSI) number and its related　key, which are used to identify and authenticate subscribers on　mobile telephony　devices (such as　mobile phones　and　computers). It is also possible to store contact information on many SIM cards.

[0120] The speaker 120 outputs sound-related results processed by the processor 102. The microphone 122 receives sound-related inputs to be used by the processor 102.

[0121] FIGS. 5 and 6 show an example of protocol stacks in a 3GPP based wireless communication system to which implementations of the present disclosure is applied.

[0122] In particular, FIG. 5 illustrates an example of a radio interface user plane protocol stack between a UE and a BS and FIG. 6 illustrates an example of a radio interface control plane protocol stack between a UE and a BS. The control plane refers to a path through which control messages used to manage call by a UE and a network are transported. The user plane refers to a path through which data generated in an application layer, for example, voice data or Internet packet data are transported. Referring to FIG. 5, the user plane protocol stack may be divided into Layer 1 (i.e., a PHY layer) and Layer 2. Referring to FIG. 6, the control plane protocol stack may be divided into Layer 1 (i.e., a PHY layer), Layer 2, Layer 3 (e.g., an RRC layer), and a non-access stratum (NAS) layer. Layer 1, Layer 2 and Layer 3 are referred to as an access stratum (AS).

[0123] In the 3GPP LTE system, the Layer 2 is split into the following sublayers: MAC, RLC, and PDCP. In the 3GPP NR system, the Layer 2 is split into the following sublayers: MAC, RLC, PDCP and SDAP. The PHY layer offers to the MAC sublayer transport channels, the MAC sublayer offers to the RLC sublayer logical channels, the RLC sublayer offers to the PDCP sublayer RLC channels, the PDCP sublayer offers to the SDAP sublayer radio bearers. The SDAP sublayer offers to 5G core network quality of service (QoS) flows.

[0124] In the 3GPP NR system, the main services and functions of the MAC sublayer include: mapping between logical channels and transport channels; multiplexing / de-multiplexing of MAC 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) (one HARQ entity per cell in case of carrier aggregation (CA)); priority handling between UEs by means of dynamic scheduling; priority handling between logical channels of one UE by means of logical channel prioritization; padding. A single MAC entity may support multiple numerologies, transmission timings and cells. Mapping restrictions in logical channel prioritization control which numerology(ies), cell(s), and transmission timing(s) a logical channel can use.

[0125] Different kinds of data transfer services are offered by MAC. To accommodate different kinds of data transfer services, multiple types of logical channels are defined, i.e., each supporting transfer of a particular type of information. Each logical channel type is defined by what type of information is transferred. Logical channels are classified into two groups: control channels and traffic channels. Control channels are used for the transfer of control plane information only, and traffic channels are used for the transfer of user plane information only. Broadcast control channel (BCCH) is a downlink logical channel for broadcasting system control information, paging control channel (PCCH) is a downlink logical channel that transfers paging information, system information change notifications and indications of ongoing public warning service (PWS) broadcasts, common control channel (CCCH) is a logical channel for transmitting control information between UEs and network and used for UEs having no RRC connection with the network, and dedicated control channel (DCCH) is a point-to-point bi-directional logical channel that transmits dedicated control information between a UE and the network and used by UEs having an RRC connection. Dedicated traffic channel (DTCH) is a point-to-point logical channel, dedicated to one UE, for the transfer of user information. A DTCH can exist in both uplink and downlink. In downlink, the following connections between logical channels and transport channels exist: BCCH can be mapped to broadcast channel (BCH); BCCH can be mapped to downlink shared channel (DL-SCH); PCCH can be mapped to paging channel (PCH); CCCH can be mapped to DL-SCH; DCCH can be mapped to DL-SCH; and DTCH can be mapped to DL-SCH. In uplink, the following connections between logical channels and transport channels exist: CCCH can be mapped to uplink shared channel (UL-SCH); DCCH can be mapped to UL-SCH; and DTCH can be mapped to UL-SCH.

[0126] The RLC sublayer supports three transmission modes: transparent mode (TM), unacknowledged mode (UM), and acknowledged node (AM). The RLC configuration is per logical channel with no dependency on numerologies and / or transmission durations. In the 3GPP NR system, the main services and functions of the RLC sublayer depend on the transmission mode and include: transfer of upper layer PDUs; sequence numbering independent of the one in PDCP (UM and AM); error correction through ARQ (AM only); segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUs; reassembly of SDU (AM and UM); duplicate detection (AM only); RLC SDU discard (AM and UM); RLC re-establishment; protocol error detection (AM only).

[0127] In the 3GPP NR system, the main services and functions of the PDCP sublayer for the user plane include: sequence numbering; header compression and decompression using robust header compression (ROHC); transfer of user data; reordering and duplicate detection; in-order delivery; PDCP PDU routing (in case of split bearers); retransmission of PDCP SDUs; ciphering, deciphering and integrity protection; PDCP SDU discard; PDCP re-establishment and data recovery for RLC AM; PDCP status reporting for RLC AM; duplication of PDCP PDUs and duplicate discard indication to lower layers. The main services and functions of the PDCP sublayer for the control plane include: sequence numbering; ciphering, deciphering and integrity protection; transfer of control plane data; reordering and duplicate detection; in-order delivery; duplication of PDCP PDUs and duplicate discard indication to lower layers.

[0128] In the 3GPP NR system, the main services and functions of SDAP include: mapping between a QoS flow and a data radio bearer; marking QoS flow ID (QFI) in both DL and UL packets. A single protocol entity of SDAP is configured for each individual PDU session.

[0129] In the 3GPP NR system, the main services and functions of the RRC sublayer include: broadcast of system information related to AS and NAS; paging initiated by 5GC or NG-RAN; establishment, maintenance and release of an RRC connection between the UE and NG-RAN; security functions including key management; establishment, configuration, maintenance and release of signaling radio bearers (SRBs) and data radio bearers (DRBs); mobility functions (including: handover and context transfer, UE cell selection and reselection and control of cell selection and reselection, inter-RAT mobility); QoS management functions; UE measurement reporting and control of the reporting; detection of and recovery from radio link failure; NAS message transfer to / from NAS from / to UE.

[0130] FIG. 7 shows an example of the overall architecture of an NG-RAN to which technical features of the present disclosure can be applied.

[0131] Referring to FIG. 7, a gNB may include a gNB-CU (hereinafter, gNB-CU may be simply referred to as CU) and at least one gNB-DU (hereinafter, gNB-DU may be simply referred to as DU).

[0132] The gNB-CU is a logical node hosting RRC, SDAP and PDCP protocols of the gNB or an RRC and PDCP protocols of the en-gNB. The gNB-CU controls the operation of the at least one gNB-DU.

[0133] The gNB-DU is a logical node hosting RLC, MAC, and physical layers of the gNB or the en-gNB. The operation of the gNB-DU is partly controlled by the gNB-CU. One gNB-DU supports one or multiple cells. One cell is supported by only one gNB-DU.

[0134] The gNB-CU and gNB-DU are connected via an F1 interface. The gNB-CU terminates the F1 interface connected to the gNB-DU. The gNB-DU terminates the F1 interface connected to the gNB-CU. One gNB-DU is connected to only one gNB-CU. However, the gNB-DU may be connected to multiple gNB-CUs by appropriate implementation. The F1 interface is a logical interface. For NG-RAN, the NG and Xn-C interfaces for a gNB consisting of a gNB-CU and gNB-DUs, terminate in the gNB-CU. For E-UTRAN-NR dual connectivity (EN-DC), the S1-U and X2-C interfaces for a gNB consisting of a gNB-CU and gNB-DUs, terminate in the gNB-CU. The gNB-CU and connected gNB-DUs are only visible to other gNBs and the 5GC as a gNB.

[0135] Functions of the F1 interface includes F1 control (F1-C) functions as follows.

[0136] (1) F1 interface management function

[0137] The error indication function is used by the gNB-DU or gNB-CU to indicate to the gNB-CU or gNB-DU that an error has occurred.

[0138] The reset function is used to initialize the peer entity after node setup and after a failure event occurred. This procedure can be used by both the gNB-DU and the gNB-CU.

[0139] The F1 setup function allows to exchange application level data needed for the gNB-DU and gNB-CU to interoperate correctly on the F1 interface. The F1 setup is initiated by the gNB-DU.

[0140] The gNB-CU configuration update and gNB-DU configuration update functions allow to update application level configuration data needed between gNB-CU and gNB-DU to interoperate correctly over the F1 interface, and may activate or deactivate cells.

[0141] The F1 setup and gNB-DU configuration update functions allow to inform the single network slice selection assistance information (S-NSSAI) supported by the gNB-DU.

[0142] The F1 resource coordination function is used to transfer information about frequency resource sharing between gNB-CU and gNB-DU.

[0143] (2) System Information management function

[0144] Scheduling of system broadcast information is carried out in the gNB-DU. The gNB-DU is responsible for transmitting the system information according to the scheduling parameters available.

[0145] The gNB-DU is responsible for the encoding of NR master information block (MIB). In case broadcast of system information block type-1 (SIB1) and other SI messages is needed, the gNB-DU is responsible for the encoding of SIB1 and the gNB-CU is responsible for the encoding of other SI messages.

[0146] (3) F1 UE context management function

[0147] The F1 UE context management function supports the establishment and modification of the necessary overall UE context.

[0148] The establishment of the F1 UE context is initiated by the gNB-CU and accepted or rejected by the gNB-DU based on admission control criteria (e.g., resource not available).

[0149] The modification of the F1 UE context can be initiated by either gNB-CU or gNB-DU. The receiving node can accept or reject the modification. The F1 UE context management function also supports the release of the context previously established in the gNB-DU. The release of the context is triggered by the gNB-CU either directly or following a request received from the gNB-DU. The gNB-CU request the gNB-DU to release the UE Context when the UE enters RRC_IDLE or RRC_INACTIVE.

[0150] This function can be also used to manage DRBs and SRBs, i.e., establishing, modifying and releasing DRB and SRB resources. The establishment and modification of DRB resources are triggered by the gNB-CU and accepted / rejected by the gNB-DU based on resource reservation information and QoS information to be provided to the gNB-DU. For each DRB to be setup or modified, the S-NSSAI may be provided by gNB-CU to the gNB-DU in the UE context setup procedure and the UE context modification procedure.

[0151] The mapping between QoS flows and radio bearers is performed by gNB-CU and the granularity of bearer related management over F1 is radio bearer level. For NG-RAN, the gNB-CU provides an aggregated DRB QoS profile and QoS flow profile to the gNB-DU, and the gNB-DU either accepts the request or rejects it with appropriate cause value. To support packet duplication for intra-gNB-DU carrier aggregation (CA), one data radio bearer should be configured with two GPRS tunneling protocol (GTP)-U tunnels between gNB-CU and a gNB-DU.

[0152] With this function, gNB-CU requests the gNB-DU to setup or change of the special cell (SpCell) for the UE, and the gNB-DU either accepts or rejects the request with appropriate cause value.

[0153] With this function, the gNB-CU requests the setup of the secondary cell(s) (SCell(s)) at the gNB-DU side, and the gNB-DU accepts all, some or none of the SCell(s) and replies to the gNB-CU. The gNB-CU requests the removal of the SCell(s) for the UE.

[0154] (4) RRC message transfer function

[0155] This function allows to transfer RRC messages between gNB-CU and gNB-DU. RRC messages are transferred over F1-C. The gNB-CU is responsible for the encoding of the dedicated RRC message with assistance information provided by gNB-DU.

[0156] (5) Paging function

[0157] The gNB-DU is responsible for transmitting the paging information according to the scheduling parameters provided.

[0158] The gNB-CU provides paging information to enable the gNB-DU to calculate the exact paging occasion (PO) and paging frame (PF). The gNB-CU determines the paging assignment (PA). The gNB-DU consolidates all the paging records for a particular PO, PF and PA, and encodes the final RRC message and broadcasts the paging message on the respective PO, PF in the PA.

[0159] (6) Warning messages information transfer function

[0160] This function allows to cooperate with the warning message transmission procedures over NG interface. The gNB-CU is responsible for encoding the warning related SI message and sending it together with other warning related information for the gNB-DU to broadcast over the radio interface.

[0161] FIG. 8 shows an interface protocol structure for E1 interface to which technical features of the present disclosure can be applied.

[0162] The TNL is based on IP transport, comprising the SCTP on top of IP. The application layer signalling protocol is referred to as E1 Application Protocol (E1AP).

[0163] Hereinafter, technical features related to Multi-Radio Dual Connectivity (MR-DC) with 5 Generation Core (5GC) are described. Sections 10.7.2 of 3GPP TS 37.340 v17.1.0 may be referred.

[0164] Inter-MN handover with / without MN initiated SN change is used to transfer UE context data from a source MN to a target MN while the UE context at the SN is kept or moved to another SN. During an Inter-Master Node handover, the target MN decides whether to keep or change the SN (or release the SN, as described in clause 10.8). Only intra-RAT Inter-Master node handover with / without SN change is supported (e.g. no transition from NGEN-DC to NR-DC).

[0165] FIGs. 9a and 9b shows an example signalling flow for inter-MN handover with / without MN initiated SN change procedure.

[0166] For an Inter-Master Node handover without Secondary Node change, the source SN and the target SN shown in FIGs. 9a and 9b are the same node.

[0167] In step S901, the source MN starts the handover procedure by initiating the Xn Handover Preparation procedure including both MCG and SCG configuration. The source MN includes the source SN UE XnAP ID, SN ID and the UE context in the source SN in theHandoverRequestmessage.

[0168] For example, the source MN may trigger the MN-initiated SN Modification procedure (to the source SN) to retrieve the current SCG configuration and to allow provision of data forwarding related information before step S901.

[0169] In step S902, if the target MN decides to keep the UE context in source SN, the target MN sendsSNAddition Requestto the SN including the SN UE XnAP ID as a reference to the UE context in the SN that was established by the source MN. If the target MN decides to change the SN allowing delta configuration, the target MN sends theSNAddition Requestto the target SN including the UE context in the source SN that was established by the source MN. Otherwise, the target MN may send theSNAddition Requestto the target SN including neither the SN UE XnAP ID nor the UE context in the source SN that was established by the source MN.

[0170] In step S903, the (target) SN replies withSNAddition Request Acknowledge. The (target) SN may include the indication of the full or delta RRC configuration.

[0171] For example, in CHO with SCG configuration, it is up to the target MN implementation to make sure that the CG-Config provided from the (target) SN can be used in all CHO preparations.

[0172] In step S903a, for SN terminated bearers using MCG resources, the target MN provides Xn-U DL TNL address information in theXn-U Address Indicationmessage.

[0173] In step S904, the target MN includes within theHandoverRequest Acknowledgemessage the MN RRC reconfiguration message to be sent to the UE in order to perform the handover, and may also provide forwarding addresses to the source MN. If PDU session split is performed in the target side during handover procedure, more than one data forwarding addresses corresponding to each node are included in theHandoverRequest Acknowledgemessage. The target MN indicates to the source MN that the UE context in the SN is kept if the target MN and the SN decided to keep the UE context in the SN in step S902 and step S903.

[0174] In step S905a and step S905b, the source MN sendsSNRelease Requestmessage to the (source) SN including a Cause indicating MCG mobility. The (source) SN acknowledges the release request. The source MN indicates to the (source) SN that the UE context in SN is kept, if it receives the indication from the target MN. If the indication as the UE context kept in SN is included, the SN keeps the UE context.

[0175] In step S905c, the source MN sends XN-U Address Indication message to the (source) SN to transfer data forwarding information. More than one data forwarding addresses may be provided if the PDU session is split in the target side.

[0176] In step S906, the source MN triggers the UE to perform handover and apply the new configuration.

[0177] In step S907 and step S908, the UE synchronizes to the target MN and replies with MN RRC reconfigurationcompletemessage.

[0178] In step S909, if configured with bearers requiring SCG radio resources, the UE synchronizes to the (target) SN.

[0179] For example, the order the UE performs Random Access towards the MN (step S907) and performs the Random Access procedure towards the SN (step S909) is not defined.

[0180] In step S910, if the RRC connection reconfiguration procedure was successful, the target MN informs the (target) SN viaSNReconfiguration Completemessage.

[0181] In step S911a, the source SN sends theSecondary RATData Usage Reportmessage to the source MN and includes the data volumes delivered to and received from the UE over the NR / E-UTRA radio.

[0182] For example, the order the source SN sends theSecondary RAT Data Usage Reportmessage and performs data forwarding with MN / target SN is not defined. The SN may send the report when the transmission of the related QoS is stopped.

[0183] In step S911b, the source MN sends theSecondary RAT Reportmessage to AMF to provide information on the used NR / E-UTRA resource.

[0184] In step S912, for bearers using RLC AM, the source MN sends theSNStatus Transfermessage to the target MN, including, if needed, SN Status received from the source SN. The target forwards the SN Status to the target SN, if needed.

[0185] In step S913, if applicable, data forwarding takes place from the source side. If the SN is kept, data forwarding may be omitted for SN terminated bearers or QoS flows kept in the SN.

[0186] In steps S914, S915, S916, and S917, the target MN initiates the Path Switch procedure.If the target MN includes multiple DL TEIDs for one PDU session in thePath Switch Requestmessage, multiple UL TEID of the UPF for the PDU session should be included in thePath SwitchAckmessage in case there is TEID update in UPF.

[0187] For example, if new UL TEIDs of the UPF for SN are included, the target MN performs MN initiated SN Modification procedure to provide them to the SN.

[0188] In step S918, the target MN initiates the UE Context Release procedure towards the source MN.

[0189] In step S919, upon reception of theUEContext Releasemessage from source MN, the (source) SN releases C-plane related resources associated to the UE context towards the source MN. Any ongoing data forwarding may continue. The SN shall not release the UE context associated with the target MN if the UE contest kept indication was included in theSNRelease Requestmessage in step S905.

[0190] Hereinafter, technical features related to S-NG-RAN node Addition Preparation are described. Sections 8.3.1 of 3GPP TS 38.423 v17.1.0 may be referred.

[0191] The purpose of the S-NG-RAN node Addition Preparation procedure is to request the S-NG-RAN node to allocate resources for dual connectivity operation for a specific UE.

[0192] The procedure uses UE-associated signalling.

[0193] FIG. 10 shows an example of a successful operation for S-NG-RAN node Addition Preparation procedure.

[0194] The M-NG-RAN node initiates the procedure by sending the S-NODE ADDITION REQUEST message to the S-NG-RAN node.

[0195] When the M-NG-RAN node sends the S-NODE ADDITION REQUEST message, it shall start the timer TXnDCprep.

[0196] The allocation of resources according to the values of theAllocation and Retention PriorityIE included in theQoS Flow Level QoS ParametersIE for each QoS flow shall follow the principles specified for the PDU Session Resource Setup procedure.

[0197] The S-NG-RAN node shall choose the ciphering algorithm based on the information in theUESecurity CapabilitiesIE and locally configured priority list of AS encryption algorithms and apply the key indicated in theS-NG-RAN node Security KeyIE.

[0198] If theTSCTraffic CharacteristicsIE is included for a QoS flow in the S-NODE ADDITION REQUEST message, the S-NG-RAN node shall behave the same as the NG-RAN node in the PDU Session Resource Setup procedure.

[0199] If theAdditional QoSFlow InformationIE is included for a QoS flow in the S-NODE ADDITION REQUEST message, the S-NG-RAN node shall behave the same as the NG-RAN node in the PDU Session Resource Setup procedure.

[0200] For each GBR QoS flow, if theAlternative QoS Parameters SetsIE is included in theGBRQoS Flow InformationIE, the S-NG-RAN node shall, if supported, behave the same as the NG-RAN node in the PDU Session Resource Setup procedure.

[0201] For each PDU session, if theNetwork InstanceIE is included in thePDUSession Resource Setup Info -SNterminatedIE contained in thePDUSession Resources To Be Added ListIE and theCommon Network InstanceIE is not present, the S-NG-RAN node shall, if supported, use it when selecting transport network resource.

[0202] For each GBR QoS flow, if theOfferedGBRQoS Flow InformationIE is included in theQoS Flows To Be Setup ListIE contained in thePDUSession Resource Setup Info -SNterminatedIE, the S-NG-RAN node may request the M-NG-RAN node to configure the DRB to which that QoS flow is mapped with MCG resources.

[0203] For each PDU session, if theNon-GBRResources OfferedIE is included in thePDUSession Resource Setup Info -SNterminatedIE contained in thePDU Session Resources To Be Added ListIE and set to "true", the S-NG-RAN node may request the M-NG-RAN node to configure DRBs to which non-GBR QoS flows of the PDU session are mapped with MCG resources.

[0204] For each PDU session, if theCommonNetwork InstanceIE is included in thePDUSession Resource Setup Info -SNterminatedIE contained in thePDUSession Resources To Be Added ListIE, the S-NG-RAN node shall, if supported, use it when selecting transport network resource.

[0205] FIG. 11 shows an example of an unsuccessful operation for S-NG-RAN node Addition Preparation procedure.

[0206] If the S-NG-RAN node is not able to accept any of the bearers or a failure occurs during the S-NG-RAN node Addition Preparation, the S-NG-RAN node sends the S-NODE ADDITION REQUEST REJECT message with an appropriate cause value to the M-NG-RAN node.

[0207] Meanwhile, the following has been captured to support data forwarding optimizations in CHO with NR-DC scenarios in Rel-18 Further NW mobility enhancement WI:

[0208] The detailed objective of this work item are:

[0209] 1. To specify mechanism and procedures of L1 / L2 based inter-cell mobility for mobility latency reduction:

[0210] > Configuration and maintenance for multiple candidate cells to allow fast application of configurations for candidate cells [RAN2, RAN3]

[0211] - Dynamic switch mechanism among candidate serving cells (including SpCell and SCell) for the potential applicable scenarios based on L1 / L2 signalling [RAN2, RAN1]

[0212] - L1 enhancements for inter-cell beam management, including L1 measurement and reporting, and beam indication [RAN1, RAN2]

[0213] > EarlyRAN2involvement is necessary, including the possibility of further clarifying the interaction between this bullet with the previous bullet

[0214] > OnlySSB-based L1 measurement is supported in this release.

[0215] - Timing Advance management [RAN1, RAN2]

[0216] - CU-DU interface signaling to support L1 / L2 mobility, if needed [RAN3]

[0217] > FR2 specific enhancements are not precluded, if any.

[0218] > The procedure of L1 / L2 based inter-cell mobility are applicable to the following scenarios:

[0219] > Standalone, CA andNR-DC case with serving cell change within one CG, prioritizingMCG

[0220] >Intra-DU case andintra-CU inter-DU case (applicable for Standalone and CA: no new RAN interfaces are expected)

[0221] > Bothintra-frequency and inter-frequency

[0222] > Both FR1 and FR2

[0223] > Source and target cells may be synchronized or non-synchronized

[0224] 2. To specify mechanism and procedures of NR-DC with selective activation of the cell groups (at least for SCG) via L3 enhancements:

[0225] - To allow subsequent cell group change after changing CG without reconfiguration and re-initiation of CPC / CPA [RAN2, RAN3, RAN4]

[0226] > A harmonized RRC modelling approach for objectives 1 and 2 could be considered to minimize the workload inRAN2.

[0227] 3. For CHO including target MCG and target SCG in NR-DC [RAN3]:

[0228] - to specify data forwarding optimizations; and

[0229] - to specify, if needed, a solution to avoid unnecessary signaling exchange between source MN and target SN.

[0230] 4. To specify CHO including target MCG and candidate SCGs for CPC / CPA in NR-DC [RAN3, RAN2]

[0231] - CHO including target MCG and target SCG is used as the baseline

[0232] 5. To specify RRM core requirements for the following, as necessary [RAN4]:

[0233] - L1 / L2-based inter-cell mobility

[0234] - Enhanced CHO configurations addressed by this WI

[0235] 6 .To specify RF requirements to cover inter-frequency L1 / L2-based mobility, as necessary [RAN4].

[0236] 7.To study and specify how to reuse the IDLE / INACTIVE mode measurement results which are to be reported during and / or after RRC connection setup / resume in order to improveSCell / SCGsetup delay [RAN4,RAN2], including:

[0237] - Availability and validation of the IDLE / INACTIVE mode measurement results to be reported [RAN4]; and

[0238] - Definition of correspondingRRMrequirements [RAN4]; and

[0239] - If necessary based onRAN4outcome, definition of corresponding signalling support [RAN2].

[0240] >RAN4will coordinate in due course withRAN2to start the work.

[0241] > R4-2220415 serves as baseline for future work inRAN4

[0242] > With exception of the above scenarios, enhancements on IDLE / INACTIVE mode measurements and onUEbehavior in IDLE / INACTIVE mode are not in scope.

[0243] Regarding the above objective, discussions has been ongoing on how to optimize early data forwarding in CHO with NR-DC scenarios, so that NW (especially, the source side) can avoid duplicated data forwarding to the target nodes before the UE executes CHO with NR-DC. Especially, CHO can be requested for multiple T-MN nodes for the same UE where the same T-SN can be reached to prepare conditional configurations for the UE's SCG. In this case, data forwarding from the source side could happen over multiple paths towards the same T-SN. This can result in forwarding duplicated data for PDU sessions or DRBs established in T-SN, when admission results for CHO NR-DC requests from different T-MNs are identical.

[0244] In addition, support for indirect data forwarding has been also discussed where there are no direct paths available, i.e., when there is no direct path between S-SN and T-SN, between S-MN and T-SN, or between S-SN and T-MN. In such cases, a node in the middle (e.g., S-MN or T-MN) should be able to decide indirect data forwarding support. If decided, then it needs to assign its own TNL address to receive the forwarded packets and relay them to the final destination accordingly.

[0245] However, such indirect data forwarding has been assumed to be supported implicitly in 3GPP, leaving up to implementation. In case of a monolithic gNB, implementations sufficed because the gNB could handle all the control and user plane functionalities. On the other hand, it has been left unspecified when a gNB is split into control plane entity (gNB-CU-CP, a.k.a. CU-CP) and user-plane entity (gNB-CU-UP, a.k.a. CU-UP). In this case, it is unclear how indirect data forwarding can be supported in the CU-UP entity dedicated to handling user plane functionalities.

[0246] Moreover, a node in the middle (e.g., S-MN or T-MN) needs to know whether PDU session or DRBs subject for data forwarding during HO or DC is terminated in MN or SN, in order to properly decide indirect forwarding support based on path availabilities. For example, T-MN needs to know whether a PDU session decided to be terminated in T-SN was originally terminated in S-MN or S-SN before HO is triggered. If terminated in S-SN but there is no direct path between S-SN and T-SN (but direct path exists between S-SN and T-MN), then T-MN can decide to perform indirect forwarding for this PDU session. If terminated in S-MN but no direct path between S-MN and T-SN, then T-MN can decide to perform indirect forwarding for this PDU session. On the other hand, if direct path exists from where a PDU session (decided to be terminated in T-SN) was originally located in the source side to T-SN, then direct forwarding is possible and there is no need for T-MN to perform indirect data forwarding for this PDU session: it can simply forward the destination TNL address to S-MN during HO preparation.

[0247] The similar logic also applies to S-MN. The S-MN also needs to know whether a PDU session subject for data forwarding is established in MN or SN in the target side during HO preparation. If established in T-SN, but originally it was hosted in S-SN and there is no direct path between S-SN and T-SN, then S-MN can decide to perform indirect forwarding for this PDU session. The same applies if established in T-MN, but originally it was hosted in S-SN and no direct path between S-SN and T-MN. On the other hand, if there exists direct path between S-SN and T-MN, then direct forwarding is possible and there is no reason for S-MN to perform indirect data forwarding for this PDU session.

[0248] In light of these considerations, information about whether a PDU session or DRB subject for data forwarding is (or was) terminated in MN or SN in the target side (or source side) is crucial for S-MN (or T-MN) to make informed decisions on indirect forwarding. The path availabilities are not enough. While it is assumed that T-MN can ascertain whether a PDU session or DRB requested to setup during HO was originally hosted in S-MN or S-SN via the inter-node RRC container ofHandoverPreparation, it is still unclear on how S-MN can know whether a PDU session or DRB subject for data forwarding is hosted in T-MN or T-SN during HO preparation.

[0249] The present disclosure introduces several mechanisms to address the above issues.

[0250] Hereinafter, a method for data forwarding in a wireless network system, according to some embodiments of the present disclosure, will be described with reference to the following drawings.

[0251] 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. Herein, a wireless device may be referred to as a user equipment (UE).

[0252] FIG. 12 shows an example of a method for data forwarding in a wireless network system, according to some embodiments of the present disclosure.

[0253] In particular, FIG. 12 shows an example of a method performed by a Central Unit (CU)-User Plane (UP) of a radio access network (RAN) node.

[0254] In step S1201, the CU-UP of the RAN node may perform data forwarding by (i) receiving data from a source RAN node and (ii) forwarding the data to a target RAN node.

[0255] For example, the data forwarding may be performed during a handover (HO) procedure and / or a Dual Connectivity (DC) procedure related to a wireless device. For example, the wireless device may be in communication with at least one of a user equipment, a network, or an autonomous vehicle other than the wireless device.

[0256] In step S1202, the CU-UP of the RAN node may receive, from the source RAN node, information informing end of the data forwarding.

[0257] For example, the information informing end of the data forwarding may include a last forwarded packet.

[0258] For example, the information informing end of the data forwarding may include an end marker.

[0259] In step S1203, the CU-UP of the RAN node may transmit, to a CU-Control Plane (CP) of the RAN node, a first message including (i) a forwarding end notification and (ii) information for resources for the data forwarding related to the forwarding end notification.

[0260] For example, the information for resources for the data forwarding may include information for one or more Transport Network Layer (TNL) addresses to be released.

[0261] For example, the information on resources for the data forwarding may include at least one Protocol Data Unit (PDU) session identity (ID) and / or at least one data radio bearer (DRB) ID.

[0262] In step S1204, the CU-UP of the RAN node may transmit, to the target RAN node, information informing end of the data forwarding.

[0263] In step S1205, the CU-UP of the RAN node may release the resources for the data forwarding.

[0264] For example, the CU-UP of the RAN node may receive, from the CU-CP, a second message including a forwarding end notification response informing that the resources for the data forwarding are released.

[0265] According to some embodiments of the present disclosure, the CU-UP may pre-assign one or more TNL addresses to be used for the data forwarding before performing the data forwarding. In this case, the CU-UP may transmit, to the CU-CP, information for the pre-assigned one or more TNL addresses. The CU-UP may receive, from the CU-CP, information for at least one TNL address for the data forwarding. For example, the at least one TNL address may be determined among the pre-assigned one or more TNL addresses.

[0266] According to some embodiments of the present disclosure, the RAN node may be a target master node (MN) and the target RAN node may be a target secondary node. In this case, the CU-UP may receive, from the CU-CP, a third message including (i) a data forwarding request and (ii) information for resources for the data forwarding, before performing the data forwarding. The information for resources for the data forwarding may be allocated and delivered from the target RAN node. The CU-UP may assign the corresponding resources for the data forwarding. The CU-UP may transmit, to the CU-CP, a fourth message including (i) a data forwarding response and (ii) information for the assigned resources for the data forwarding.

[0267] Hereinafter, an embodiment (that is, Embodiment 1) for indirect data forwarding support in T-MN is described.

[0268] T-MN CU-CP, after adding T-SN and knowing there is no direct path between the source and T-SN, can decide to perform indirect data forwarding for some PDU sessions or DRBs established in T-SN and subject for data forwarding. T-MN CU-CP requests T-MN CU-UP to perform indirect data forwarding and provides the forwarding TNL addresses received from T-SN for those PDU sessions and DRBs, and by retrieving the corresponding forwarding TNL addresses assigned by T-MN CU-UP. The forwarding TNL addresses retrieved from T-MN CU-UP replaces those corresponding forwarding TNL addresses received from T-SN and are delivered to the source for data forwarding as part of HO procedure. T-MN CU-UP performs indirect data forwarding by relaying the forwarded packets received from the source to the forwarding TNL addresses provided by T-MN CU-CP.

[0269] FIG. 13 shows a flow chart for indirect data forwarding support in T-MN.

[0270] In particular, FIG. 13 describes when T-MN decides indirect data forwarding for some PDU sessions or DRBs established in T-SN and subject for data forwarding in its CU-UP entity.

[0271] In step S1301, the source initiates HO toward T-MN CU-CP for a UE.

[0272] In step S1302 and step S1303, based on measurement results, T-MN CU-CP decides to add a secondary node for this UE and performs SN Addition procedure with T-SN. For PDU sessions and DRBs requested to setup in T-SN, T-SN performs admission control. For PDU sessions or DRBs established in T-SN and subject to data forwarding (for which T-SN accepted data forwarding proposal from the source), T-SN provides the corresponding forwarding TNL addresses to T-MN CU-CP, along with its direct path availability information with the source side (S-MN or S-SN).

[0273] In step S1304, based on direct path availability information received from T-SN, and based on information whether PDU sessions or DRBs successfully established in T-SN were originally located in S-MN or S-SN before HO is triggered (for which T-MN CU-CP can know through the inter-node RRC container ofHandoverPreparationvia step S1301), T-MN makes decisions on whether to perform indirect data forwarding for each PDU session or DRB established in T-SN and subject for data forwarding.

[0274] For example, if T-SN indicated direct path not available with S-SN, but T-MN has direct path with S-SN, then T-MN may decide to perform indirect data forwarding for PDU sessions and DRBs established in T-SN and subject to data forwarding for which was originally hosted in S-SN.

[0275] For example, if T-SN indicated direct path not available with S-MN, then T-MN may decide to perform indirect data forwarding for PDU sessions and DRBs established in T-SN and subject to data forwarding for which was originally hosted in S-MN.

[0276] If decided for indirect data forwarding, T-MN CU-CP requests T-MN CU-UP to perform indirect data forwarding and provides the corresponding forwarding TNL addresses received from T-SN in step S1303.

[0277] In step S1305, T-MN CU-UP assigns the corresponding forwarding TNL addresses for each forwarding TNL address received from T-MN CU-CP and provides the assigned forwarding TNL addresses back to T-MN CU-CP.

[0278] In step S1306, T-MN CU-CP replaces the forwarding TNL addresses received from T-SN with the received forwarding TNL addresses assigned by T-MN CU-UP and deliver them to the source as part of HO procedure.

[0279] In case when T-SN indicated no direct path available with S-SN, if there is some PDU sessions or DRBs originally hosted in S-SN and established in T-SN, for which T-MN CU-CP decided not to perform indirect data forwarding, those forwarding TNL addresses (received from T-SN) could be forwarded to the source as part of HO procedure, if T-SN indicated that it has a direct path with S-MN, expecting S-MN to support indirect data forwarding instead for those forwarding TNL addresses.

[0280] On the other hand, if T-SN indicated that it has no direct path available with the source side at all (i.e. with S-MN and S-SN), then this basically means that direct data forwarding is not possible toward T-SN unless indirect forwarding is performed at T-MN. If decided not performed at T-MN, then T-MN may not forward those forwarding TNL addresses received from T-SN as part of HO procedure (so that data forwarding is not initiated from the source side). In this case, T-MN may send end markers to terminate data forwarding procedure for those forwarding TNL addresses to T-SN, who thinks data forwarding is accepted and is expecting to received forwarded data.

[0281] Hereinafter, an embodiment (that is, Embodiment 2) for indirect data forwarding support in S-MN is described.

[0282] S-MN CU-CP, after receiving HANDOVER REQUEST ACKNOWLEDGE message from the target side and knowing that there is no direct path between S-SN and the target side, and knowing whether PDU sessions or DRBs admitted by the target is established in T-MN or T-SN, can decide to perform indirect data forwarding for some PDU sessions or DRBs admitted by the target side and subject for data forwarding. S-MN CU-CP requests S-MN CU-UP to perform indirect data forwarding and provides the forwarding TNL addresses received from the target side for those PDU sessions and DRBs, and by retrieving the corresponding forwarding TNL addresses assigned by S-MN CU-UP. The forwarding TNL addresses retrieved from S-MN CU-UP replaces those corresponding forwarding TNL addresses received from the target side and are delivered to S-SN for data forwarding. S-MN CU-UP performs indirect data forwarding by relaying the forwarded packets received from S-SN to the forwarding TNL addresses provided by S-MN CU-CP.

[0283] FIG. 14 shows a flow chart for indirect data forwarding support in S-MN.

[0284] FIG. 14 describes when S-MN decides indirect data forwarding for some PDU sessions or DRBs admitted by the target and subject for data forwarding in its CU-UP entity.

[0285] In step S1401, S-MN CU-CP initiates HO toward the target for a UE.

[0286] In step S1402, the target performs admission control and responses back to S-MN CU-CP. For PDU sessions and DRBs admitted by the target side and subject to data forwarding, the target provides the corresponding forwarding TNL addresses to S-MN CU-CP, along with its direct path availability information with S-SN. The target also provides whether PDU sessions or DRBs are admitted by T-MN or T-SN.

[0287] In step S1403, based on the received information from the target in step S1402, and based on whether PDU sessions or DRBs admitted by the target were originally located in S-MN or S-SN before HO is triggered, S-MN CU-CP decides whether to perform indirect data forwarding for each PDU session or DRB admitted by the target and subject for data forwarding.

[0288] For example, if the target indicated that direct path is not available between S-SN and T-SN, then S-MN may decide to perform indirect data forwarding for PDU sessions and DRBs established in T-SN and subject to data forwarding for which was originally hosted in S-SN.

[0289] For example, if the target indicated that direct path is not available between S-SN and T-MN, then S-MN may decide to perform indirect data forwarding for PDU sessions and DRBs established in T-MN and subject to data forwarding for which was originally hosted in S-SN.

[0290] If decided for indirect data forwarding, S-MN CU-CP requests S-MN CU-UP to perform indirect data forwarding and provides the corresponding forwarding TNL addresses received from the target side in step S1402.

[0291] In step S1404, S-MN CU-UP assigns the corresponding forwarding TNL addresses for each forwarding TNL address received from S-MN CU-UP and provides the assigned forwarding TNL addresses back to S-MN CU-CP.

[0292] In step S1405, S-MN CU-CP replaces the forwarding TNL addresses received from the target side with the received forwarding TNL addresses assigned by S-MN CU-UP and deliver them to S-SN. For some PDU sessions or DRBs admitted by the target side for which S-MN CU-CP decided not to perform indirect data forwarding, those forwarding TNL addresses (received from the target side) are forwarded to S-SN.

[0293] This procedure can also be applicable to SN change scenario where the target in FIG. 14 is another SN, and SN addition procedure is used in step S1401 and step S1402. In this case, information on whether PDU sessions or DRBs are admitted by T-MN or T-SN is not applicable.

[0294] Hereinafter, an embodiment (that is, Embodiment 3) for indirect data forwarding termination from CU-UP is described.

[0295] The indirect data forwarding is completed when the last forwarded packet (i.e. end marker) is received and forwarded. When CU-UP receives an end marker packet in its forwarding TNL address (assigned for the purpose of indirect forwarding), CU-UP notifies CU-CP the release of indirect data forwarding from this TNL address, while forwarding the end marker to the forwarding TNL address that was configured from CU-CP.

[0296] FIG. 15 shows a flow chart for indirect data forwarding termination from CU-UP.

[0297] FIG. 15 describes the procedure to release indirect data forwarding support from CU-UP that can be applicable to Embodiment 1 and Embodiment 2 when indirect data forwarding is completed.

[0298] In step S1501, CU-UP (either S-MN CU-UP or T-MN CU-UP) receives the last forwarded packet (i.e. end marker) which indicates the end of data forwarding in its forwarding TNL address.

[0299] In step S1502, CU-UP informs CU-CP (S-MN CU-CP or T-MN CU-CP) that indirect data forwarding is completed. CU-UP can inform which forwarding TNL addresses received end marker packets and to be released. CU-UP may also inform their corresponding forwarding TNL addresses that were configured from CU-CP to forward the received packets to.

[0300] In step S1503, CU-CP confirms the release of indirect data forwarding for the indicated forwarding TNL addresses from CU-UP.

[0301] In step S1504, CU-UP forwards the last received packet (i.e. end marker) to the corresponding forwarding TNL addresses that were configured from CU-CP and release the resources allocated for indirect data forwarding that were completed.

[0302] For example, in this embodiment (that is, Embodiment 3), step S1503 can be skipped.

[0303] For other example, in this embodiment (that is, Embodiment 3), step S1504 may happen before step S1502.

[0304] Hereinafter, an embodiment (that is, Embodiment 4) for resource pooling for indirect data forwarding support in CU-UP.

[0305] A pool of resources could be reserved, and forwarding TNL addresses could be pre-assigned in CU-UP and informed to CU-CP for the purpose of supporting indirect data forwarding. CU-CP then can use the pre-assigned forwarding TNL addresses at CU-UP for indirect forwarding and configure CU-UP to which TNL to forward the received packets to.

[0306] FIG. 16 shows a flow chart for resource pooling for indirect data forwarding support in CU-UP.

[0307] FIG. 16 describes the procedure for resource pooling of pre-assigning forwarding TNL addresses for indirect data forwarding in CU-UP, which can be applicable to Embodiments 1 and 2.

[0308] In step S1601, CU-UP (either S-MN CU-UP or T-MN CU-UP) pre-assigns the forwarding TNL addresses to be used for the support of indirect data forwarding.

[0309] In step S1602, CU-UP delivers the pre-assigned forwarding TNL addresses to CU-CP (S-MN CU-CP or T-MN CU-CP).

[0310] In step S1603, Once CU-CP decides indirect data forwarding during HO or DC procedure, CU-CP configures CU-UP with which pre-assigned TNL addresses are used for indirect data forwarding, and their corresponding forwarding TNL addresses to forward the received packets to.

[0311] In step S1604, CU-UP starts indirect data forwarding.

[0312] Hereinafter, examples of methods according to some embodiments of the present disclosure are described.

[0313] (1): A method of supporting indirect data forwarding in the network system during HO or DC procedure.

[0314] (2): A method of (1), where the network system comprises network nodes interconnected by X2 or Xn interface.

[0315] (3): A method of (2), where the network nodes may comprise of control plane (CU-CP) and user-plane (CU-UP) interconnected by E1 interface.

[0316] (4): A method of (3), where the target node may decide indirect data forwarding for PDU sessions or DRBs established in the target SN (secondary node).

[0317] (4-1): A method of (4), wherein the information in deciding indirect data forwarding may include direct path availability with the source nodes, and from where PDU sessions or DRBs (established in the target SN and subject for data forwarding) was originated in the source nodes.

[0318] (5): A method of (3) where the target node CU-CP may request its CU-UP entity to perform indirect data forwarding and provide the forwarding TNL addresses received from the target SN.

[0319] (5-1): A method of (5) where CU-UP assigns the corresponding forwarding TNL addresses for each forwarding TNL address received from the target node CU-CP and responses back the assigned forwarding TNL addresses.

[0320] (5-2) A method of (5) where the target node CU-CP replaces the forwarding TNL addresses received from the target SN with the received forwarding TNL addresses assigned by its CU-UP entity and deliver them to the source nodes.

[0321] (6) A method of (3), where the source node may decide indirect data forwarding for PDU sessions or DRBs established in the target nodes.

[0322] (6-1) A method of (6), wherein the information in deciding indirect data forwarding may include direct path availability with the target nodes, and from where PDU sessions or DRBs originally hosted in the source SN (secondary node) was established in the target nodes.

[0323] (7) A method of (6) where the source node CU-CP may request its CU-UP entity to perform indirect data forwarding and provide the forwarding TNL addresses received from the target nodes.

[0324] (7-1) A method of (7) where CU-UP assigns the corresponding forwarding TNL addresses for each forwarding TNL address received from the source node CU-CP and responses back the assigned forwarding TNL addresses.

[0325] (7-2) A method of (7) where the source node CU-CP replaces the forwarding TNL addresses received from the target nodes with the received forwarding TNL addresses assigned by its CU-UP entity and deliver them to the source SN.

[0326] (8) A method of (5) or (7), where CU-UP informs the end of data forwarding to CU-CP.

[0327] (8-1) A method of (8), where the information from CU-UP may include which forwarding TNL address received the last forwarded packet and about to be released, and their corresponding forwarding TNL address that was configured from CU-CP to forward the received packets to.

[0328] (8-2) A method of (8), where CU-CP confirms the release of indirect data forwarding for the indicated forwarding TNL addresses from CU-UP.

[0329] (8-3) A method of (8), where CU-UP forwards the last received packet to the corresponding forwarding TNL addresses that were configured from CU-CP and release the resources allocated for indirect data forwarding that were completed.

[0330] (9) A method of (5) or (7), where CU-UP pre-assigns the forwarding TNL addresses to be used for the support of indirect data forwarding.

[0331] (9-1) A method of (9) where CU-UP informs the pre-assigned forwarding TNL addresses to CU-CP.

[0332] (9-2) A method of (9) where CU-CP who decided indirect data forwarding configures CU-UP with which pre-assigned TNL addresses are used for indirect data forwarding, and their corresponding forwarding TNL addresses to forward the received packets to, so that CU-UP can start perform indirect data forwarding accordingly.

[0333] FIG. 17 shows an example of a method for indirect data forwarding in a wireless network system, according to some embodiments of the present disclosure.

[0334] For example, a handover for a wireless device may be performed from a source to a target. The target may include a target Master Node (MN) and a target Secondary Node (SN). The Target MN may include at least one Central Unit (CU)-Control Plane (CP), at least one Central Unit (CU)-User Plane (UP), and at least one Distributed Unit (DU).

[0335] In particular, FIG. 17 shows an example of a method performed by a Central Unit (CU)-Control Plane (CP) of a radio access network (RAN) node (for example, the CU-CP of a target MN).

[0336] In step S1701, the CU-CP (for example, the CU-CP of the target MN) may transmit, to a CU-UP of the RAN node (for example, the CU-UP of the target MN), a first message including (i) information requesting to perform indirect data forwarding, (ii) information related to a forwarding transport layer, and (iii) information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer.

[0337] For example, before step S1701, the CU-CP of the target Master Node (MN) may transmit, to a target Secondary Node (SN), a S-NG-RAN node Addition Request message. The CU-CP may receive, from the target SN, a S-NG-RAN node Addition RequestAcknowledgement message.

[0338] For example, the CU-CP of the target MN may receive, from, a target SN, the information related to the forwarding transport layer. For example, the information related to the forwarding transport layer may be included in the S-NG-RAN node Addition Request Acknowledgement message or a new message.

[0339] For example, before step S1701, the CU-CP of the source Master Node (MN) may transmit, to a target RAN node, a Handover Request message. The CU-CP may receive, from the target RAN node, a Handover Request Acknowledgement message.

[0340] For example, the CU-CP of the source MN may receive, from, a target RAN node, the information related to the forwarding transport layer. For example, the information related to the forwarding transport layer may be included in the Handover Request Acknowledgement message or a new message.

[0341] For example, the CU-CP of the source MN may receive, from the target RAN node, information related to whether the PDU session or DRBs admitted by a target MN or target SN. For example, the information related to whether the PDU session or DRBs admitted by a target MN or target SN may be included in the Handover Request Acknowledgement message or a new message.

[0342] For example, the CU-CP may receive, from the target RAN node, information informing whether the direct path available with the target SN or not. For example, the information informing whether the direct path available with the target SN or not may be included in the Handover Request Acknowledgement message or a new message.

[0343] For example, before step S1701, the CU-CP may decide whether to perform indirect data forwarding, based on the information informing whether the direct path available with the target SN or not.

[0344] For example, the forwarding transport layer may be associated with a TNL address related to at least one PDU session and / or at least one DRB established in a target Secondary Node (SN).

[0345] For example, the information requesting to perform indirect data forwarding may be included in a Special Triggering Purpose Information Element (IE).

[0346] For example, the Special Triggering Purpose IE may be included in PDU Session Resource To Setup Modification List IE contained in the BEARER CONTEXT MODIFICATION REQUEST message. The gNB-CU-UP may consider that the setup of the DRB or the PDU session for which the IE is included is for the purpose of indirect data forwarding. For example, the Special Triggering Purpose IE may be included in PDU Session Resource To Modify List IE contained in the BEARER CONTEXT MODIFICATION REQUEST message. The gNB-CU-UP may store the bearer context information and consider that the setup of the DRB for which the IE is included is for the purpose of indirect data forwarding.

[0347] For example, the Special Triggering Purpose Information Element (IE) may be set to the purpose of indirect data forwarding.

[0348] For example, for the purpose of supporting indirect data forwarding, target MN-CU-CP is now allowed to retrieve reception TNL addresses and to configure forwarding TNL addresses with target MN-CU-UP simultaneously via a single round-trip procedure over E1AP for setup the indirect data forwarding.

[0349] For example, the single round-trip procedure for configuring the indirect data forwarding may be possible as follows. For example, target MN may decide to split PDU session (for example, in dual connectivity, one PDU session can be divided into MN and SN. Some QoS flows within the PDU session for a UE can be served by the MN and some QoS flows within the PDU session for the UE can be served by the SN). The target MN-CU-CP could first establish a related PDU session in target MN-CU-UP before adding target SN, and then add target SN. At this time, the target SN may not know whether direct or indirect data forwarding with the source is possible or not. Thus, the Special Triggering Purpose may not be used in such a Bearer Context Setup Request message. In other words, the before step S1701, the target MN-CU-UP may not receive the information requesting to perform indirect data forwarding from the target SN. Afterwards, while adding the target SN, the remaining QoS flows of the split PDU session may be also successfully established in the target SN, creating an SN DRB. When target SN accepts the DRB data forwarding proposed by the source RAN node, it may reply to the target MN (that is, the CU-CP) and inform whether there is a direct path with the source. (For example, at the same time, the forwarding TNL address allocated for data forwarding from the source may be also notified to the target MN). If target SN transmits information informing that there is no direct path, target MN-CU-CP can establish a DRB for indirect data forwarding in target MN-CU-UP for the DRB of the target SN (under that split PDU session). At this time, in a second message (for example, the Bearer Context Modification Request message), a request to establish a DRB of the target SN may be made through DRB To Setup List included in PDU Session Resource To Modify List. Since this is a DRB for indirect data forwarding purposes, "Special Triggering Purpose" could be used. At the same time, the target MN-CU-CP may request the target MN-CU-UP to allocate the TNL address of the corresponding PDU session or DRB to receive the forwarded data from the source. The forwarding TNL address information of target SN for the relevant DRB can also be provided at the same time through DRB To Modify List within the same Bearer Context Modification Request message (for example, through PDU Session Resource To Modify List). And due to the request to allocate the TNL address of the corresponding PDU session or DRB, target MN-CU-UP allocates the corresponding TNL address. The target MN-CU-UP may transmit information including the allocated TNL address back to the target MN-CU-CP.

[0350] For example, the information related to the forwarding transport layer may be included in a Data Forwarding Information IE. For example, the information related to the forwarding transport layer may be included in a PDU Session Data Forwarding Information IE or a DRB Data Forwarding Information IE. For example, the Data Forwarding Information IE may include uplink (UL) Data Forwarding information or downlink (DL) Data Forwarding information (for example, UP Transport Layer Information). For example, this Data Forwarding Information IE may provide the data forwarding address information during handover or data offloading.

[0351] For example, when performing a Handover, the source can request data forwarding, which is separately divided into UL or DL data forwarding request, to the target. Accordingly, the target can individually accept UL and / or DL data forwarding. The target can individually allocate the corresponding TNL address and transmit information related to the allocated TNL address to the source.

[0352] For example, the DRB requiring PDCP SN preservation (that is, mapped to RLC AM) may be used to transfer the out-of-sequence PDCP SNs that was not successfully delivered to the CN among the UL PDCP SDUs received from the UE during HO to the target side. (Then the target can send a PDCP Status Report to the UE and request that it resend only the missing PDCP SDUs).

[0353] For example, the information requesting to allocate a receiving TNL corresponding to the forwarding TNL may be included in a Data Forwarding Information Request IE. For example, the information requesting to allocate a receiving TNL corresponding to the forwarding TNL may be included in a PDU Session Data Forwarding Information Request IE or a DRB Data Forwarding Information Request IE.

[0354] For example, the Data Forwarding Information Request IE may offer the possibility for the gNB-CU-CP to request data forwarding addresses to be allocated by the gNB-CU-UP. It also offers the possibility for the gNB-CU-CP to provide a list of QoS flows subject to PDU Session level or DRB level data forwarding to the gNB to which DRBs or QoS flows have been offloaded. For example, the Data Forwarding Information Request IE may be included an enumerated type data (for example, informing UL, DL, both, or etc.)

[0355] For example, the first message may be a Bearer Context Modification Request message.

[0356] In step S1702, the CU-CP may receive, from the CU-UP, a second message, in response to the first message, including information related to an allocated receiving transport layer.

[0357] For example, the allocated receiving transport layer may be associated with a TNL address related to the CU-UP for the indirect data forwarding. For example, the information related to the allocated receiving transport layer may be included in a PDU Session Data Forwarding Information Response IE or a DRB Data Forwarding Information Response IE.

[0358] For example, the second message may include a Bearer Context Modification Response message.

[0359] For example, the CU-CP may transmit, to a source SN, the information related to the allocated receiving transport layer. For example, the information related to the allocated receiving transport layer may be included in an Xn-U Address Indication.

[0360] For example, the indirect data forwarding may include (i) transmission of a data packet from a source RAN node to the CU-UP and (ii) transmission of the data packet from the CU-UP to a target SN.

[0361] For example, the transmission of the data packet from the source RAN node to the CU-UP may be performed based on the information related to the allocated receiving transport layer. That is, the source RAN node may transmit, to the CU-UP, the data packet based on the information related to the allocated receiving transport layer (for example, the TNL address of the CU-UP).

[0362] For example, the transmission of the data packet from the CU-UP to the target SN may be performed based on the information related to the forwarding transport layer.

[0363] That is, the CU-UP may forward, to the target SN, the data packet based on the information related to the forwarding transport layer (for example, the TNL address of the target SN).

[0364] In other words, upon receiving the first message from the CU-CP in step S1701, the CU-UP may allocate a receiving TNL address, which is mapped to the receiving target SN's forwarding TNL address (at the request of the target MN-CU-CP), and deliver it back to the target MN-CU-CP.

[0365] That is, when forwarding data from the source side (for example, a source MN or a source SN) to a target SN, the target MN-CU-UP may play a relay role in the middle due to the absence of a direct path between the source side and the target SN.

[0366] The information related to the target MN-CU-UP's receiving TNL address may be transmitted to the source side. When forwarding data from source to target, packets may be first delivered to target MN-CU-UP's receiving TNL address. The target MN-CU-UP, which received the forwarded packet to the corresponding TNL, may relay the received packet to the target SN's forwarding TNL address to perform the role of indirect data forwarding.

[0367] Some of the detailed steps shown in the examples of FIG. 12, FIG. 13, FIG. 14, FIG. 15, FIG. 16, and FIG. 17 may not be essential steps and may be omitted. In addition to the steps shown in FIG. 12, FIG. 13, FIG. 14, FIG. 15, FIG. 16, and FIG. 17, other steps may be added, and the order of the steps may vary. Some of the above steps may have their own technical meaning.

[0368] Hereinafter, an apparatus for data forwarding in a wireless network system, according to some embodiments of the present disclosure, will be described.

[0369] Herein, the RAN node may be the gNB in FIG. 7. The RAN node may comprise a transceiver, a memory, and at least one processor. The at least one processor may be operatively coupled to the memory and the transceiver.

[0370] For example, a handover for a wireless device may be performed from a source to a target. The target may include a target Master Node (MN) and a target Secondary Node (SN). The Target MN may include at least one Central Unit (CU)-Control Plane (CP), at least one Central Unit (CU)-User Plane (UP), and at least one Distributed Unit (DU).

[0371] For example, the RAN node may be a target Master Node. The RAN node may include at least one Central Unit (CU)-User Plane (UP), at least one Central Unit (CU)-Control Plane (CP), and at least one Distributed Unit (DU). The CU-CP may include a memory and at least one processor. The CU-UP may include a memory and at least one processor.

[0372] The at least one processor may be adapted to control the CU-CP to transmit, to a CU-User Plane (UP) of the RAN node, a first message including (i) information requesting to perform indirect data forwarding, (ii) information related to a forwarding transport layer, and (iii) information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer. The at least one processor may be adapted to control the CU-CP to receive, from the CU-UP, a second message, in response to the first message, including information related to an allocated receiving transport layer.

[0373] For example, the forwarding transport layer is associated with a TNL address related to at least one PDU session and / or at least one DRB established in a target Secondary Node (SN).

[0374] For example, the allocated receiving transport layer is associated with a TNL address related to the CU-UP for the indirect data forwarding.

[0375] For example, the indirect data forwarding includes (i) transmission of a data packet from a source RAN nodeto the CU-UP and (ii) transmission of the data packet from the CU-UP to a target SN. For example, the transmission of the data packet from the source RAN node to the CU-UP is performed based on the information related to the allocated receiving transport layer. For example, the transmission of the data packet from the CU-UP to the target SN is performed based on the information related to the forwarding transport layer.

[0376] For example, the at least one processor may be adapted to control the CU-CP to transmit, to a source SN, the information related to the allocated receiving transport layer.

[0377] For example, the information requesting to perform indirect data forwarding is included in a Special Triggering Purpose Information Element (IE).

[0378] For example, the information related to the forwarding transport layer is included in a Data Forwarding Information IE.

[0379] For example, the information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer is included in a Data Forwarding Information Request IE.

[0380] For example, the first message includes a Bearer Context Modification Request message.

[0381] For example, the second message includes a Bearer Context Modification Response message.

[0382] For example, the at least one processor may be adapted to control the CU-CP to receive, from, a target SN, the information related to the forwarding transport layer.

[0383] The at least one processor may be adapted to control the CU-UP to perform data forwarding by (i) receiving data from a source RAN node and (ii) forwarding the data to a target RAN node. The at least one processor may be adapted to control the CU-UP to receive, from the source RAN node, information informing end of the data forwarding. The at least one processor may be adapted to control the CU-UP to transmit, to a CU-Control Plane (CP) of the RAN node, a first message including (i) a forwarding end notification and (ii) information for resources for the data forwarding related to the forwarding end notification. The at least one processor may be adapted to control the CU-UP to transmit, to the target RAN node, information informing end of the data forwarding. The at least one processor may be adapted to control the CU-UP to release the resources for the data forwarding.

[0384] For example, the at least one processor may be adapted to control the CU-UP to receive, from the CU-CP, a second message including a forwarding end notification response informing that the resources for the data forwarding are released.

[0385] For example, the information informing end of the data forwarding may include a last forwarded packet.

[0386] For example, the information informing end of the data forwarding may include an end marker.

[0387] For example, the information for resources for the data forwarding may include information for one or more Transport Network Layer (TNL) addresses to be released.

[0388] For example, the information on resources for the data forwarding may include at least one Protocol Data Unit (PDU) session identity (ID) and / or at least one data radio bearer (DRB) ID.

[0389] For example, the at least one processor may be adapted to control the CU-UP to pre-assign one or more TNL addresses to be used for the data forwarding before performing the data forwarding. The at least one processor may be adapted to control the CU-UP to transmit, to the CU-CP, information for the pre-assigned one or more TNL addresses. The at least one processor may be adapted to control the CU-UP to receive, from the CU-CP, information for at least one TNL address for the data forwarding. The at least one TNL address may be determined among the pre-assigned one or more TNL addresses.

[0390] For example, the RAN node may be a target master node (MN) and the target RAN node may be a target secondary node. The at least one processor may be adapted to control the CU-UP to receive, from the CU-CP, a third message including (i) a data forwarding request and (ii) information for resources for the data forwarding, before performing the data forwarding. The information for resources for the data forwarding may be transmitted from the target RAN node. The at least one processor may be adapted to control the CU-UP to assign the resources for the data forwarding. The at least one processor may be adapted to control the CU-UP to transmit, to the CU-CP, a fourth message including (i) a data forwarding response and (ii) information for the assigned resources for the data forwarding.

[0391] For example, the data forwarding may be performed during a handover (HO) procedure and / or a Dual Connectivity (DC) procedure related to a wireless device. For example, the wireless device may be in communication with at least one of a user equipment, a network, or an autonomous vehicle other than the wireless device.

[0392] Hereinafter, a processor for a Central Unit (CU)-Control Plane (CP) of a RAN node for data forwarding in a wireless network system, according to some embodiments of the present disclosure, will be described.

[0393] For example, a handover for a wireless device may be performed from a source to a target. The target may include a target Master Node (MN) and a target Secondary Node (SN). The Target MN may include at least one Central Unit (CU)-Control Plane (CP), at least one Central Unit (CU)-User Plane (UP), and at least one Distributed Unit (DU).

[0394] For example, the RAN node may be a target Master Node. The RAN node may include at least one Central Unit (CU)-User Plane (UP), at least one CU-Control Plane (CP), and at least one Distributed Unit (DU). The CU-CP may include a memory and at least one processor. The CU-UP may include a memory and at least one processor.

[0395] The processor may be configured to control the CU-CP to transmit, to a CU-User Plane (UP) of the RAN node, a first message including (i) information requesting to perform indirect data forwarding, (ii) information related to a forwarding transport layer, and (iii) information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer. The processor may be configured to control the CU-CP to receive, from the CU-UP, a second message, in response to the first message, including information related to an allocated receiving transport layer.

[0396] For example, the forwarding transport layer is associated with a TNL address related to at least one PDU session and / or at least one DRB established in a target Secondary Node (SN).

[0397] For example, the allocated receiving transport layer is associated with a TNL address related to the CU-UP for the indirect data forwarding.

[0398] For example, the indirect data forwarding includes (i) transmission of a data packet from a source RAN node to the CU-UP and (ii) transmission of the data packet from the CU-UP to a target SN. For example, the transmission of the data packet from the source RAN node to the CU-UP is performed based on the information related to the allocated receiving transport layer. For example, the transmission of the data packet from the CU-UP to the target SN is performed based on the information related to the forwarding transport layer.

[0399] For example, the processor may be configured to control the CU-CP to transmit, to a source SN, the information related to the allocated receiving transport layer.

[0400] For example, the information requesting to perform indirect data forwarding is included in a Special Triggering Purpose Information Element (IE).

[0401] For example, the information related to the forwarding transport layer is included in a Data Forwarding Information IE.

[0402] For example, the information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer is included in a Data Forwarding Information Request IE.

[0403] For example, the first message includes a Bearer Context Modification Request message.

[0404] For example, the second message includes a Bearer Context Modification Response message.

[0405] For example, the processor may be configured to control the CU-CP to receive, from, a target SN, the information related to the forwarding transport layer.

[0406] Hereinafter, a processor for a Central Unit (CU)-User Plane (UP) of a RAN node for data forwarding in a wireless network system, according to some embodiments of the present disclosure, will be described.

[0407] The processor may be configured to control the CU-UP to perform data forwarding by (i) receiving data from a source RAN node and (ii) forwarding the data to a target RAN node. The processor may be configured to control the CU-UP to receive, from the source RAN node, information informing end of the data forwarding. The processor may be configured to control the CU-UP to transmit, to a CU-Control Plane (CP) of the RAN node, a first message including (i) a forwarding end notification and (ii) information for resources for the data forwarding related to the forwarding end notification. The processor may be configured to control the CU-UP to transmit, to the target RAN node, information informing end of the data forwarding. The processor may be configured to control the CU-UP to release the resources for the data forwarding.

[0408] For example, the processor may be configured to control the CU-UP to receive, from the CU-CP, a second message including a forwarding end notification response informing that the resources for the data forwarding are released.

[0409] For example, the information informing end of the data forwarding may include a last forwarded packet.

[0410] For example, the information informing end of the data forwarding may include an end marker.

[0411] For example, the information for resources for the data forwarding may include information for one or more Transport Network Layers (TNL) addresses to be released.

[0412] For example, the information on resources for the data forwarding may include at least one Protocol Data Unit (PDU) session identity (ID) and / or at least one data radio bearer (DRB) ID.

[0413] For example, the processor may be configured to control the CU-UP to pre-assign one or more TNL addresses to be used for the data forwarding before performing the data forwarding. The processor may be configured to control the CU-UP to transmit, to the CU-CP, information for the pre-assigned one or more TNL addresses. The processor may be configured to control the CU-UP to receive, from the CU-CP, information for at least one TNL address for the data forwarding. The at least one TNL address may be determined among the pre-assigned one or more TNL addresses.

[0414] For example, the RAN node may be a target master node (MN) and the target RAN node may be a target secondary node. The processor may be configured to control the CU-UP to receive, from the CU-CP, a third message including (i) a data forwarding request and (ii) information for resources for the data forwarding, before performing the data forwarding. The information for resources for the data forwarding may be transmitted from the target RAN node. The processor may be configured to control the CU-UP to assign the resources for the data forwarding. The processor may be configured to control the CU-UP to transmit, to the CU-CP, a fourth message including (i) a data forwarding response and (ii) information for the assigned resources for the data forwarding.

[0415] For example, the data forwarding may be performed during a handover (HO) procedure and / or a Dual Connectivity (DC) procedure related to a wireless device. For example, the wireless device may be in communication with at least one of a user equipment, a network, or an autonomous vehicle other than the wireless device.

[0416] Hereinafter, a non-transitory computer-readable medium has stored thereon a plurality of instructions for data forwarding in a wireless network system, according to some embodiments of the present disclosure, will be described.

[0417] According to some embodiment of the present disclosure, the technical features of the present disclosure could be embodied directly in hardware, in a software executed by a processor, or in a combination of the two. For example, a method performed by a wireless device in a wireless communication may be implemented in hardware, software, firmware, or any combination thereof. For example, a software may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other storage medium.

[0418] Some example of storage medium is coupled to the processor such that the processor can read information from the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. For another example, the processor and the storage medium may reside as discrete components.

[0419] The computer-readable medium may include a tangible and non-transitory computer-readable storage medium.

[0420] For example, non-transitory computer-readable media may include random access memory (RAM) such as synchronous dynamic random access memory (SDRAM), read-only memory (ROM), non-volatile random access memory (NVRAM), electrically erasable programmable read-only memory (EEPROM), FLASH memory, magnetic or optical data storage media, or any other medium that can be used to store instructions or data structures. Non-transitory computer-readable media may also include combinations of the above.

[0421] In addition, the method described herein may be realized at least in part by a computer-readable communication medium that carries or communicates code in the form of instructions or data structures and that can be accessed, read, and / or executed by a computer.

[0422] According to some embodiment of the present disclosure, a non-transitory computer-readable medium has stored thereon a plurality of instructions. The stored a plurality of instructions may be executed by a processor of a Central Unit (CU)-Control Plane (CP) of a radio access network (RAN) node.

[0423] For example, a handover for a wireless device may be performed from a source to a target. The target may include a target Master Node (MN) and a target Secondary Node (SN). The Target MN may include at least one Central Unit (CU)-Control Plane (CP), at least one Central Unit (CU)-User Plane (UP), and at least one Distributed Unit (DU).

[0424] For example, the RAN node may be a target Master Node. The RAN node may include at least one Central Unit (CU)-User Plane (UP), at least one Central Unit (CU)-Control Plane (CP), and at least one Distributed Unit (DU). The CU-CP may include a memory and at least one processor. The CU-UP may include a memory and at least one processor.

[0425] The stored a plurality of instructions may cause the CU-CP to transmit, to a CU-User Plane (UP) of the RAN node, a first message including (i) information requesting to perform indirect data forwarding, (ii) information related to a forwarding transport layer, and (iii) information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer. The stored a plurality of instructions may cause the CU-UP to receive, from the CU-UP, a second message, in response to the first message, including information related to an allocated receiving transport layer.

[0426] For example, the forwarding transport layer is associated with a TNL address related to at least one PDU session and / or at least one DRB established in a target Secondary Node (SN).

[0427] For example, the allocated receiving transport layer is associated with a TNL address related to the CU-UP for the indirect data forwarding.

[0428] For example, the indirect data forwarding includes (i) transmission of a data packet from a source RAN node to the CU-UP and (ii) transmission of the data packet from the CU-UP to a target SN. For example, the transmission of the data packet from the source RAN node to the CU-UP is performed based on the information related to the allocated receiving transport layer. For example, the transmission of the data packet from the CU-UP to the target SN is performed based on the information related to the forwarding transport layer.

[0429] For example, the stored a plurality of instructions may cause the CU-UP to transmit, to a source SN, the information related to the allocated receiving transport layer.

[0430] For example, the information requesting to perform indirect data forwarding is included in a Special Triggering Purpose Information Element (IE).

[0431] For example, the information related to the forwarding transport layer is included in a Data Forwarding Information IE.

[0432] For example, the information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer is included in a Data Forwarding Information Request IE.

[0433] For example, the first message includes a Bearer Context Modification Request message.

[0434] For example, the second message includes a Bearer Context Modification Response message.

[0435] For example, the stored a plurality of instructions may cause the CU-UP to receive, from, a target SN, the information related to the forwarding transport layer.

[0436] According to some embodiment of the present disclosure, a non-transitory computer-readable medium has stored thereon a plurality of instructions. The stored a plurality of instructions may be executed by a processor of a Central Unit (CU)-User Plane (UP) of a radio access network (RAN) node.

[0437] The stored a plurality of instructions may cause the CU-UP to perform data forwarding by (i) receiving data from a source RAN node and (ii) forwarding the data to a target RAN node. The stored a plurality of instructions may cause the CU-UP to receive, from the source RAN node, information informing end of the data forwarding. The stored a plurality of instructions may cause the CU-UP to transmit, to a CU-Control Plane (CP) of the RAN node, a first message including (i) a forwarding end notification and (ii) information for resources for the data forwarding related to the forwarding end notification. The stored a plurality of instructions may cause the CU-UP to transmit, to the target RAN node, information informing end of the data forwarding. The stored a plurality of instructions may cause the CU-UP to release the resources for the data forwarding.

[0438] For example, the stored a plurality of instructions may cause the CU-UP to receive, from the CU-CP, a second message including a forwarding end notification response informing that the resources for the data forwarding are released.

[0439] For example, the information informing end of the data forwarding may include a last forwarded packet.

[0440] For example, the information informing end of the data forwarding may include an end marker.

[0441] For example, the information for resources for the data forwarding may include information for one or more Transport Network Layer (TNL) addresses to be released.

[0442] For example, the information on resources for the data forwarding may include at least one Protocol Data Unit (PDU) session identity (ID) and / or at least one data radio bearer (DRB) ID.

[0443] For example, the stored a plurality of instructions may cause the CU-UP to pre-assign one or more TNL addresses to be used for the data forwarding before performing the data forwarding. The stored a plurality of instructions may cause the CU-UP to transmit, to the CU-CP, information for the pre-assigned one or more TNL addresses. The stored a plurality of instructions may cause the CU-UP to receive, from the CU-CP, information for at least one TNL address for the data forwarding. The at least one TNL address may be determined among the pre-assigned one or more TNL addresses.

[0444] For example, the RAN node may be a target master node (MN) and the target RAN node may be a target secondary node. The stored a plurality of instructions may cause the CU-UP to receive, from the CU-CP, a third message including (i) a data forwarding request and (ii) information for resources for the data forwarding, before performing the data forwarding. The information for resources for the data forwarding may be transmitted from the target RAN node. The stored a plurality of instructions may cause the CU-UP to assign the resources for the data forwarding. The stored a plurality of instructions may cause the CU-UP to transmit, to the CU-CP, a fourth message including (i) a data forwarding response and (ii) information for the assigned resources for the data forwarding.

[0445] For example, the data forwarding may be performed during a handover (HO) procedure and / or a Dual Connectivity (DC) procedure related to a wireless device. For example, the wireless device may be in communication with at least one of a user equipment, a network, or an autonomous vehicle other than the wireless device.

[0446] Hereinafter, a wireless device for data forwarding in a wireless network system, according to some embodiments of the present disclosure, will be described.

[0447] The wireless device may include a transceiver, a memory, and a processor operatively coupled to the transceiver and the memory. For example, the wireless device may be the first wireless device 100 or the second wireless device 200 of FIGS. 2 and 3, or the UE 100 of FIG. 4.

[0448] The processor may be adapted to receive, from a source Radio Access Network (RAN) node, a Radio Resource Control (RRC) reconfiguration message for handover (HO) and / or dual connectivity (DC) related to a target RAN node. The processor may be adapted to transmit, from the source RAN node, data to be forwarded to the target RAN node.

[0449] For example, the source RAN node may transmit, to a Central Unit (CU)-User Plane (UP) of a RAN node, information informing end of data forwarding. For example, the CU-UP may transmit, to a CU-Control Plane (CP) of the RAN node, a first message including (i) a forwarding end notification and (ii) information for resources for the data forwarding related to the forwarding end notification. For example, the CU-UP may transmit, to the target RAN node, information informing end of the data forwarding. For example, the CU-UP may release the resources for the data forwarding.

[0450] Hereinafter, a method performed by a wireless device for data forwarding in a wireless network system, according to some embodiments of the present disclosure, will be described.

[0451] The wireless device may receive, from a source Radio Access Network (RAN) node, a Radio Resource Control (RRC) reconfiguration message for handover (HO) and / or dual connectivity (DC) related to a target RAN node. The wireless device may transmit, from the source RAN node, data to be forwarded to the target RAN node.

[0452] For example, the source RAN node may transmit, to a Central Unit (CU)-User Plane (UP) of a RAN node, information informing end of data forwarding. For example, the CU-UP may transmit, to a CU-Control Plane (CP) of the RAN node, a first message including (i) a forwarding end notification and (ii) information for resources for the data forwarding related to the forwarding end notification. For example, the CU-UP may transmit, to the target RAN node, information informing end of the data forwarding. For example, the CU-UP may release the resources for the data forwarding.

[0453] The present disclosure can have various advantageous effects.

[0454] According to some embodiments of the present disclosure, the network could efficiently support for indirect data forwarding and / or direct data forwarding during Handover (HO) or Dual Connectivity (DC).

[0455] For example, embodiments described in this present disclosure enables network nodes to support indirect data forwarding during HO or DC procedures when there are no direct paths available between the source and target entities, and also enables indirect data forwarding in Central Unit (CU)-User Plane (UP) entities (in short, CU-UP) dedicated to handle all the user plane functionalities.

[0456] For example, when there is no direct path between the source and target nodes, network nodes can efficiently support indirect data forwarding and / or direct data forwarding during HO or DC procedures.

[0457] For example, the CU-UP entity can efficiently perform indirect data forwarding and / or direct data forwarding.

[0458] 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.

[0459] Claims in the present disclosure can be combined in a various way. For instance, technical features in method claims of the present disclosure 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.

Claims

1.A method performed by a Central Unit (CU)-Control Plane (CP) of a radio access network (RAN) node in a wireless communication system, the method comprising:transmitting, to a CU-User Plane (UP) of the RAN node, a first message including (i) information requesting to perform indirect data forwarding, (ii) information related to a forwarding transport layer, and (iii) information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer; andreceiving, from the CU-UP, a second message, in response to the first message, including information related to an allocated receiving transport layer.2.The method of claim 1,wherein the forwarding transport layer is associated with a TNL (Transport Network Layer) address related to at least one PDU session and / or at least one DRB established in a target Secondary Node (SN).3.The method of claim 1,wherein the allocated receiving transport layer is associated with a TNL address related to the CU-UP for the indirect data forwarding.4.The method of claim 1,wherein the indirect data forwarding includes (i) transmission of a data packet from a source RAN node to the CU-UP and (ii) transmission of the data packet from the CU-UP to a target SN (secondary node).5.The method of claim 4,wherein the transmission of the data packet from the source RAN node to the CU-UP is performed based on the information related to the allocated receiving transport layer.6.The method of claim 4,wherein the transmission of the data packet from the CU-UP to the target SN is performed based on the information related to the forwarding transport layer.7.The method of claim 1, wherein the method further comprising:transmitting, to a source SN, the information related to the allocated receiving transport layer.8.The method of claim 1,wherein the information requesting to perform indirect data forwarding is included in a Special Triggering Purpose Information Element (IE).9.The method of claim 1,wherein the information related to the forwarding transport layer is included in a Data Forwarding Information IE.10.The method of claim 1,wherein the information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer is included in a Data Forwarding Information Request IE.11.The method of claim 1,wherein the first message includes a Bearer Context Modification Request message.12.The method of claim 1,wherein the second message includes a Bearer Context Modification Response message.13.The method of claim 1, wherein the method further comprising:receiving, from, a target SN, the information related to the forwarding transport layer.14.A Central Unit (CU)-Control Plane (CP) of a radio access network (RAN) node in a wireless communication system comprising:a transceiver;a memory; andat least one processor operatively coupled to the memory and the transceiver, and adapted to:transmit, to a CU-User Plane (UP) of the RAN node, a first message including (i) information requesting to perform indirect data forwarding, (ii) information related to a forwarding transport layer, and (iii) information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer; andreceive, from the CU-UP, a second message, in response to the first message, including information related to an allocated receiving transport layer.15.The CU-CP of claim 14,wherein the forwarding transport layer is associated with a TNL address related to at least one PDU session and / or at least one DRB established in a target Secondary Node (SN).16.The CU-CP of claim 14,wherein the allocated receiving transport layer is associated with a TNL address related to the CU-UP for the indirect data forwarding.17.The CU-CP of claim 14,wherein the indirect data forwarding includes (i) transmission of a data packet from a source RAN node to the CU-UP and (ii) transmission of the data packet from the CU-UP to a target SN.18.The CU-CP of claim 17,wherein the transmission of the data packet from the source RAN node to the CU-UP is performed based on the information related to the allocated receiving transport layer.19.The CU-CP of claim 17,wherein the transmission of the data packet from the CU-UP to the target SN is performed based on the information related to the forwarding transport layer.20.The CU-CP of claim 14, wherein the at least one processor is further adapted to:transmit, to a source SN, the information related to the allocated receiving transport layer.21.The CU-CP of claim 14,wherein the information requesting to perform indirect data forwarding is included in a Special Triggering Purpose Information Element (IE).22.The CU-CP of claim 14,wherein the information related to the forwarding transport layer is included in a Data Forwarding Information IE.23.The CU-CP of claim 14,wherein the information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer is included in a Data Forwarding Information Request IE.24.The CU-CP of claim 14,wherein the first message includes a Bearer Context Modification Request message.25.The CU-CP of claim 14,wherein the second message includes a Bearer Context Modification Response message.26.The CU-CP of claim 14, wherein the at least one processor is further adapted to:receive, from, a target SN, the information related to the forwarding transport layer.27.A processor for a Central Unit (CU)-Control Plane (CP) of a radio access network (RAN) node in a wireless communication system, wherein the processor is configured to control the CU-CP to perform operations comprising:transmitting, to a CU-User Plane (UP) of the RAN node, a first message including (i) information requesting to perform indirect data forwarding, (ii) information related to a forwarding transport layer, and (iii) information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer; andreceiving, from the CU-UP, a second message, in response to the first message, including information related to an allocated receiving transport layer.28.A non-transitory computer-readable medium having stored thereon a plurality of instructions, which, based on executed by a processor of a Central Unit (CU)-Control Plane (CP) of a radio access network (RAN) node, perform operations, the operations comprises,transmitting, to a CU-User Plane (UP) of the RAN node, a first message including (i) information requesting to perform indirect data forwarding, (ii) information related to a forwarding transport layer, and (iii) information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer; andreceiving, from the CU-UP, a second message, in response to the first message, including information related to an allocated receiving transport layer.29.A method for a wireless device in a wireless communication system, the method comprising,receiving, from a source Radio Access Network (RAN) node, a Radio Resource Control (RRC) reconfiguration message for handover (HO) and / or dual connectivity (DC) related to a target Master Node (MN) and a target Secondary Node (SN); andtransmitting, from the source RAN node, data to be forwarded to the target SN,wherein a Central Unit (CU)-Control Plane (CP) of the target MN transmits, to a CU-User Plane (UP) of the target MN, a first message including (i) information requesting to perform indirect data forwarding, (ii) information related to a forwarding transport layer, and (iii) information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer, andwherein the CU-CP receives, from the CU-UP, a second message, in response to the first message, including information related to an allocated receiving transport layer.30.A wireless device in a wireless communication system comprising:a transceiver;a memory; anda processor operatively coupled to the transceiver and the memory, and adapted to:receive, from a source Radio Access Network (RAN) node, a Radio Resource Control (RRC) reconfiguration message for handover (HO) and / or dual connectivity (DC) related to a target Master Node (MN) and a target Secondary Node (SN); andtransmit, from the source RAN node, data to be forwarded to the target SN,wherein a Central Unit (CU)-Control Plane (CP) of the target MN transmits, to a CU-User Plane (UP) of the target MN, a first message including (i) information requesting to perform indirect data forwarding, (ii) information related to a forwarding transport layer, and (iii) information requesting to allocate a receiving transport layer corresponding to the forwarding transport layer, andwherein the CU-CP receives, from the CU-UP, a second message, in response to the first message, including information related to an allocated receiving transport layer.

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