Mobility procedure

Abstract

The present disclosure provides a method performed by a UE. The method may include: receiving, by a User Equipment (UE) from a first base station, a configuration message; transmitting, by the UE to the first base station, a response message; and based on that one or more conditions of the at least one execution condition are satisfied, selecting a target cell, based on information related to an access technology.

Description

MOBILITY PROCEDURE

[0001] The present specification relates to a radio communication.

[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] According to the conventional art, a mobility procedure such as handover may be performed inefficiently. For example, since a conventional handover procedure considers only signal strength, it fails to take into account characteristics of various services of the UE, a service type, and service requirements.

[0006] In one aspect, a method is provided. The method may comprise: receiving, by a User Equipment (UE) from a first base station, a configuration message; transmitting, by the UE to the first base station, a response message; and based on that one or more conditions of the at least one execution condition are satisfied, selecting a target cell, based on information related to an access technology.

[0007] In another aspect, an appartus performing the above method is provided.

[0008] In one aspect, a method is provided. The method may comprise: transmitting, by a first base station to a UE, a configuration message; and receiving, by first base station from the UE, a response message, based on that one or more conditions of the at least one execution condition are satisfied, a target cell is selected by the UE, based on information related to an access technology.

[0009] In another aspect, an appartus performing the above method is provided.

[0010] FIG. 1 shows an example of a communication system to which implementations of the present disclosure is applied.

[0011] FIG. 2 shows an example of wireless devices to which implementations of the present disclosure is applied.

[0012] FIG. 3 shows an example of UE to which implementations of the present disclosure is applied.

[0013] FIG. 4 shows an example of 5G system architecture to which implementations of the present disclosure is applied.

[0014] FIGS. 5a through 5e shows an example of RACH procedures applicable to an embodiment of the present disclosure.

[0015] FIGS. 6a to 6c illustrate an example of a conditional handover procedure according to one embodiment of the present disclosure.

[0016] FIGS. 7a and 7b illustrate an example of an overall CHO procedure according to one embodiment of the present disclosure.

[0017] FIG. 8 illustrates an example of operations related to ACHO performed by a UE according to one embodiment of the present disclosure.

[0018] FIG. 9 illustrates an example in which a UE performs operations related to ACHO and / or CHO according to one embodiment of the present disclosure.

[0019] FIGS. 10a and 10b illustrate an example of a procedure according to one embodiment of the present disclosure.

[0020] FIG. 11 illustrates an example of an operation according to an embodiment of the present disclosure.

[0021] 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 Multi Carrier 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 downlink (DL) and SC-FDMA in uplink (UL). Evolution of 3GPP LTE includes LTE-Advanced (LTE-A), LTE-A Pro, and / or 5G New Radio (NR).

[0022] 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.

[0023] 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.

[0024] 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".

[0025] 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".

[0026] 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".

[0027] 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".

[0028] 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".

[0029] Technical features that are separately described in one drawing in the present disclosure may be implemented separately or simultaneously.

[0030] 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.

[0031] 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.

[0032] FIG. 1 shows an example of a communication system to which implementations of the present disclosure is applied.

[0033] 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.

[0034] 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).

[0035] 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.

[0036] 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.

[0037] The wireless devices 100a to 100f represent devices performing communication using Radio Access Technology (RAT) (e.g., 5G 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 Internet-of-Things (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 Augmented Reality (AR) / Virtual Reality (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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] NR supports multiples numerologies (and / or multiple Sub-Carrier 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.

[0042] The NR frequency band may be defined as two types of frequency range, i.e., Frequency Range 1 (FR1) and Frequency Range 2 (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).

[0043] Frequency Range designationCorresponding frequency rangeSubcarrier SpacingFR1450MHz - 6000MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0044] 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).

[0045] Frequency Range designationCorresponding frequency rangeSubcarrier SpacingFR1410MHz - 7125MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0046] Here, the radio communication technologies implemented in the wireless devices in the present disclosure may include NarrowBand IoT (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 MTC (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.

[0047] FIG. 2 shows an example of wireless devices to which implementations of the present disclosure is applied.

[0048] In FIG. 2, The first wireless device 100 and / or the second wireless device 200 may be implemented in various forms according to use cases / services. For example, {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. The first wireless device 100 and / or the second wireless device 200 may be configured by various elements, devices / parts, and / or modules.

[0049] 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.

[0050] The processing chip 101 may include at least one processor, such a processor 102, and at least one memory, such as a memory 104. Additional and / or alternatively, the memory 104 may be placed outside of the processing chip 101.

[0051] The processor 102 may control the memory 104 and / or the transceiver 106 and may be adapted 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.

[0052] 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 firmware and / or a software code 105 which implements codes, commands, and / or a set of commands 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 firmware and / or 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 firmware and / or the software code 105 may control the processor 102 to perform one or more protocols. For example, the firmware and / or the software code 105 may control the processor 102 to perform one or more layers of the radio interface protocol.

[0053] 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.

[0054] 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.

[0055] The processing chip 201 may include at least one processor, such a processor 202, and at least one memory, such as a memory 204. Additional and / or alternatively, the memory 204 may be placed outside of the processing chip 201.

[0056] The processor 202 may control the memory 204 and / or the transceiver 206 and may be adapted 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.

[0057] 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 firmware and / or a software code 205 which implements codes, commands, and / or a set of commands 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 firmware and / or 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 firmware and / or the software code 205 may control the processor 202 to perform one or more protocols. For example, the firmware and / or the software code 205 may control the processor 202 to perform one or more layers of the radio interface protocol.

[0058] 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.

[0059] 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), one or more Service Data Unit (SDUs), 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.

[0060] 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. For example, the one or more processors 102 and 202 may be configured by a set of a communication control processor, an Application Processor (AP), an Electronic Control Unit (ECU), a Central Processing Unit (CPU), a Graphic Processing Unit (GPU), and a memory control processor.

[0061] 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 Random Access Memory (RAM), Dynamic RAM (DRAM), Read-Only Memory (ROM), electrically Erasable Programmable Read-Only Memory (EPROM), flash memory, volatile memory, non-volatile memory, hard drive, register, cash memory, computer-readable storage medium, 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.

[0062] 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.

[0063] The one or more transceivers 106 and 206 may be connected to the one or more antennas 108 and 208. Additionally and / or alternatively, the one or more transceivers 106 and 206 may include one or more antennas 108 and 208. The one or more transceivers 106 and 206 may be adapted 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).

[0064] 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.

[0065] Although not shown in FIG. 2, the wireless devices 100 and 200 may further include additional components. 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, an Input / Output (I / O) device (e.g., audio I / O port, video I / O port), a driving device, and a computing device. The additional components 140 may be coupled to the one or more processors 102 and 202 via various technologies, such as a wired or wireless connection.

[0066] 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 adapted 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 adapted 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.

[0067] In the present disclosure, a BS is also referred to as a node B (NB), an eNode B (eNB), or a gNB.

[0068] FIG. 3 shows an example of UE to which implementations of the present disclosure is applied.

[0069] Referring to FIG. 3, a UE 100 may correspond to the first wireless device 100 of FIG. 2.

[0070] A UE 100 includes a processor 102, a memory 104, a transceiver 106, one or more antennas 108, a power management module 141, a battery 142, a display 143, a keypad 144, a Subscriber Identification Module (SIM) card 145, a speaker 146, and a microphone 147.

[0071] The processor 102 may be adapted to implement the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure. The processor 102 may be adapted 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 DSP, CPU, 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.

[0072] 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.

[0073] 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.

[0074] The power management module 141 manages power for the processor 102 and / or the transceiver 106. The battery 142 supplies power to the power management module 141.

[0075] The display 143 outputs results processed by the processor 102. The keypad 144 receives inputs to be used by the processor 102. The keypad 144 may be shown on the display 143.

[0076] The SIM card 145 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.

[0077] The speaker 146 outputs sound-related results processed by the processor 102. The microphone 147 receives sound-related inputs to be used by the processor 102.

[0078] FIG. 4 shows an example of 5G system architecture to which implementations of the present disclosure is applied.

[0079] The 5G system (5GS) architecture consists of the following network functions (NF).

[0080] - Authentication Server Function (AUSF)

[0081] - Access and Mobility Management Function (AMF)

[0082] - Data Network (DN), e.g., operator services, Internet access or 3rd party services

[0083] - Unstructured Data Storage Function (UDSF)

[0084] - Network Exposure Function (NEF)

[0085] - Intermediate NEF (I-NEF)

[0086] - Network Repository Function (NRF)

[0087] - Network Slice Selection Function (NSSF)

[0088] - Policy Control Function (PCF)

[0089] - Session Management Function (SMF)

[0090] - Unified Data Management (UDM)

[0091] - Unified Data Repository (UDR)

[0092] - User Plane Function (UPF)

[0093] - UE radio Capability Management Function (UCMF)

[0094] - Application Function (AF)

[0095] - User Equipment (UE)

[0096] - (Radio) Access Network ((R)AN)

[0097] - 5G-Equipment Identity Register (5G-EIR)

[0098] - Network Data Analytics Function (NWDAF)

[0099] - CHarging Function (CHF)

[0100] Furthermore, the following network functions may be considered.

[0101] - Non-3GPP InterWorking Function (N3IWF)

[0102] - Trusted Non-3GPP Gateway Function (TNGF)

[0103] - Wireline Access Gateway Function (W-AGF)

[0104] FIG. 4 depicts the 5G system architecture in the non-roaming case, using the reference point representation showing how various network functions interact with each other.

[0105] In FIG. 4, for the sake of clarity of the point-to-point diagrams, the UDSF, NEF and NRF have not been depicted. However, all depicted Network Functions can interact with the UDSF, UDR, NEF and NRF as necessary.

[0106] For clarity, the UDR and its connections with other NFs, e.g., PCF, are not depicted in FIG. 4. For clarity, the NWDAF and its connections with other NFs, e.g., PCF, are not depicted in FIG. 4.

[0107] The 5G system architecture contains the following reference points:

[0108] - N1: Reference point between the UE and the AMF.

[0109] - N2: Reference point between the (R)AN and the AMF.

[0110] - N3: Reference point between the (R)AN and the UPF.

[0111] - N4: Reference point between the SMF and the UPF.

[0112] - N6: Reference point between the UPF and a Data Network.

[0113] - N9: Reference point between two UPFs.

[0114] The following reference points show the interactions that exist between the NF services in the NFs.

[0115] - N5: Reference point between the PCF and an AF.

[0116] - N7: Reference point between the SMF and the PCF.

[0117] - N8: Reference point between the UDM and the AMF.

[0118] - N10: Reference point between the UDM and the SMF.

[0119] - N11: Reference point between the AMF and the SMF.

[0120] - N12: Reference point between the AMF and the AUSF.

[0121] - N13: Reference point between the UDM and the AUSF.

[0122] - N14: Reference point between two AMFs.

[0123] - N15: Reference point between the PCF and the AMF in the case of non-roaming scenario, PCF in the visited network and AMF in the case of roaming scenario.

[0124] - N16: Reference point between two SMFs, (in roaming case between SMF in the visited network and the SMF in the home network).

[0125] - N22: Reference point between the AMF and the NSSF.

[0126] In some cases, a couple of NFs may need to be associated with each other to serve a UE.

[0127] FIGS. 5a through 5e shows an example of RACH procedures applicable to an embodiment of the present disclosure.

[0128] Referring to FIGS. 5a through 5e, a RACH procedure is described, according to one embodiment of the present disclosure. The embodiments of Figures 6a through 6e may be combined with various embodiments of the present disclosure.

[0129] In one embodiment of the disclosure, where RF requirements (e.g., Tx RF performance requirements and / or Rx RF performance requirements) are described, the UE may satisfy those RF requirements. For example, a UE may be tested to satisfy RF requirements (e.g., Tx RF performance requirements and / or Rx Rf performance requirements) according to one embodiment of the disclosure. In one embodiment of the disclosure, a UE that meets these RF requirements may perform the RACH procedure. When the UE transmits messages, data, signaling, etc. to the gNB, the UE satisfies the Tx RF performance requirements described in the first embodiment of this specification. When the UE receives messages, data, signaling, etc. from the gNB, the UE satisfies the Rx RF performance requirements described in the first embodiment of this specification.

[0130] To connect the UE to the 5G network, the UE and the 5G network must synchronize in the uplink and downlink. Downlink synchronization is performed when the UE successfully decodes the SSB transmitted by the gNB. To establish the uplink synchronization and RRC connection, the UE shall perform the RACH random access procedure.

[0131] Two types of random access procedures are supported. The two types of random access procedures include a four-stage Random Access (RA) type using MSG1 and a two-stage RA type using MSGA.

[0132] The two types of RA procedures can support Contention Based Random Access (CBRA) and Contention Free Random Access (CFRA), as shown in Figure 5a through Figure 5e below, respectively. The UE may select the random access type at the beginning of the random access procedure, depending on the network configuration.

[0133] Referring to Figure 5a and Figure 5c, a four-stage RA type using MSG1 is illustrated.

[0134] Step 4 The MSG1 of RA type contains the preamble of the PRACH. The UE transmits the MSG1. After the UE sends the MSG1, the UE monitors the network for a response within the set window.

[0135] For CBRA according to the example of FIG. 5a, when the UE receives a random access response (MSG2) from the gNB, the UE may transmit MSG3 using the UL grant scheduled by the response message. The UE may then monitor the contention resolution. If contention resolution is not successful after the MSG3 (re)transmission, the UE shall perform the MSG1 transmission again.

[0136] For CFRA according to the example in FIG. 5c, a dedicated preamble for MSG1 transmission is allocated by the network. The gNB sends the RA preamble assignment to the UE. The UE transmits an MSG1 containing the random access preamble to the gNB. Upon receiving the random access response from the network, the UE terminates the random access procedure.

[0137] Referring to FIGS. 5b, 5d, and 5e, a two-stage RA type is described. The MSGA of the two-stage RA type includes a random access preamble on the PRACH and a PUSCH payload. After the UE transmits the MSGA, the UE monitors the response from the network within a set window.

[0138] For CBRA according to the example of FIG. 5b, after the UE receives the network response (e.g., MSGB), if the contention resolution is successful, the UE terminates the random access procedure. If the fallback indication is received within the MSGB, the UE performs the MSG3 transmission using the UL grant scheduled in the fallback indication and monitors the contention resolution, as shown in Figure 5e. If contention resolution is not successful after the MSG3 (re)transmission, the UE shall perform the MSGA transmission again.

[0139] In the case of CFRA according to the example of FIG. 5d, the UE may receive RA preamble allocation and PUSCH allocation from the gNB. Dedicated preamble and PUSCH resources may then be set up for MSGA transmission. The UE transmits the MSGA. When the UE receives a network response, the UE terminates the random access procedure.

[0140] If the random access procedure of the two-stage RA type is not completed after several MSGA transmissions, the UE may be set to switch to the CBRA of the four-stage RA type.

[0141] In the present disclosure, a handover is an example of a mobility procedure. Accordingly, descriptions related to the handover may also apply to a mobility procedure. In the present disclosure, a conditional handover may be an example of a conditional mobility procedure, and adaptive conditional handover (ACHO) may be an example of an adaptive conditional mobility procedure.

[0142] The Conditional Handover (CHO) is described herein. 3GPP TS 38.300 v19.0.0 clause 9.2.3.4 Conditional Handover may be refered.

[0143] A Conditional Handover (CHO) is defined as a handover that is executed by the UE when one or more handover execution conditions are met. The UE starts evaluating the execution condition(s) upon receiving the CHO configuration, and stops evaluating the execution condition(s) once a handover is executed.

[0144] The following principles apply to CHO:

[0145] - The CHO configuration includes the configuration of CHO candidate cell(s) generated by the candidate gNodeB(gNB)(s) and execution condition(s) generated by the source gNB.

[0146] - An execution condition may includes one or two trigger condition(s) (e.g., CHO events A3 / A5, as defined in 3GPP TS 38.331 V18.4.0). Only single RS type is supported and at most two different trigger quantities (e.g. Reference Signal Received Power (RSRP) and Reference Signal Received Quality (RSRQ), RSRP and Signal-to-Interference-plus-Noise Ratio (SINR), etc.) can be configured simultaneously for the evalution of CHO execution condition of a single candidate cell.

[0147] - Before any CHO execution condition is satisfied, upon reception of Handover (HO) command (without CHO configuration) or L1 / L2-triggered mobility cell (LTM) cell switch command Medium Access Control Control Element (MAC CE), the UE executes the HO procedure as described in 3GPP TS 38.300 v19.0.0 clause 9.2.3.2 or LTM cell switch procedure as described in clause 9.2.3.5, regardless of any previously received CHO configuration.

[0148] - While executing CHO, i.e., from the time when the UE starts synchronization with target cell, UE does not monitor source cell.

[0149] C-plane handling for CHO is described herein.

[0150] As in intra-NR RAN handover, in intra-NR RAN CHO, the preparation and execution phase of the conditional handover procedure is performed without involvement of the 5GC. For example, preparation messages are directly exchanged between gNBs. The release of the resources at the source gNB during the conditional handover completion phase is triggered by the target gNB. The figure below depicts the basic conditional handover scenario where neither the AMF nor the UPF changes.

[0151] The following drawings are intended to illustrate specific embodiments of the present disclosure. The designations of specific devices or the designations of specific signals / messages / fields shown in the drawings are for illustrative purposes only, and the technical features of the present specification are not limited to the specific designations used in the drawings below.

[0152] FIGS. 6a to 6c illustrate an example of a conditional handover procedure according to one embodiment of the present disclosure.

[0153] FIGS. 6a to 6c illustrate an example of intra-AMF / intra-UPF Conditional Handover procedure.

[0154] A UE transmits User Data to a UPF(s) via a source gNB. The UE receives User Data from the UPF(s) via the source gNB.

[0155] 0. Mobility control information may be provided by an AMF.

[0156] 1. Measurement Control and Reports may be performed.

[0157] Step 0 and step 1 may be performed same as step 0, 1 in Figure 9.2.3.2.1-1 of clause 9.2.3.2.1 of 3GPP TS 38.300 v19.0.0.

[0158] 2. The source gNB decides to use CHO.

[0159] 3. The source gNB requests CHO for one or more candidate cells belonging to one or more candidate gNBs. A CHO request message is sent for each candidate cell.

[0160] 4. Target gNB and / or Other potential target gNB(s) performs admission control. Same as step 4 in Figure 9.2.3.2.1-1 of clause 9.2.3.2.1 of 3GPP TS 38.300 v19.0.0.

[0161] 5. The candidate gNB(s) sends CHO response (HO REQUEST ACKNOWLEDGE) including configuration of CHO candidate cell(s) to the source gNB. The CHO response message is sent for each candidate cell.

[0162] 6. The source gNB sends anRRCReconfigurationmessage to the UE, including the configuration of CHO candidate cell(s) and CHO execution condition(s).

[0163] For example, CHO configuration of candidate cells can be followed by another reconfiguration from the source gNB.

[0164] A configuration of a CHO candidate cell cannot contain a Dual Active Protocol Stack handover (DAPS) handover configuration.

[0165] 7. The UE sends anRRCReconfigurationCompletemessage to the source gNB.

[0166] 7a If early data forwarding is applied, the source gNB sends the EARLY STATUS TRANSFER message.

[0167] 8. The UE maintains connection with the source gNB after receiving CHO configuration, and starts evaluating the CHO execution conditions for the candidate cell(s). If at least one CHO candidate cell satisfies the corresponding CHO execution condition, the UE detaches from the source gNB, applies the stored corresponding configuration for that selected candidate cell, synchronises to that candidate cell and completes the RRC handover procedure by sendingRRCReconfigurationCompletemessage to the target gNB. The UE releases stored CHO configurations after successful completion of RRC handover procedure.

[0168] 8a / b The target gNB sends the HANDOVER SUCCESS message to the source gNB to inform that the UE has successfully accessed the target cell. In return, the source gNB sends the SN STATUS TRANSFER message following the principles described in step 7 of Intra-AMF / UPF Handover in clause 9.2.3.2.1 of 3GPP TS 38.300 v19.0.0.

[0169] Late data forwarding may be initiated as soon as the source gNB receives the HANDOVER SUCCESS message.

[0170] 8c. The source gNB sends the HANDOVER CANCEL message toward the other signalling connections or other candidate target gNBs, if any, to cancel CHO for the UE.

[0171] U-plane handling for CHO is described herein.

[0172] The U-plane handling for Conditional Handover follows the same principles for DAPS handover in clause 9.2.3.2.2 of 3GPP TS 38.300 v19.0.0, if early data forwarding is applied, except that, in case of Full Configuration, HFN and PDCP SN are reset in the target gNB after the SN assignment is handed over to the target gNB. If late data forwarding is applied, the U-plane handling follows the RLC-AM or RLC-UM bearer principles defined in 9.2.3.2.2 of 3GPP TS 38.300 v19.0.0.

[0173] Data Forwarding for CHO is described herein.

[0174] If late data forwarding is applied, the source NG-RAN node initiates data forwarding once it knows which target NG-RAN node the UE has successfully accessed. In that case the behavior of the Conditional Handover data forwarding follows the same behavior as defined in clause 9.2.3.2.3 of 3GPP TS 38.300 v19.0.0 for the intra-system handover data forwarding, except the behavior for Data Radio Bearers (DRBs) configured with DAPS handover.

[0175] If early data forwarding is applied instead, the source NG-RAN node initiates data forwarding before the UE executes the handover, to a candidate target node of interest. The behavior of early data forwarding for the Conditional Handover follows the same principles for DRBs configured with DAPS handover in the intra-system handover as defined in clause 9.2.3.2.3 of 3GPP TS 38.300 v19.0.0.

[0176] In Release 16, Conditional Handover (CHO) mechanism is introduced in 3GPP. CHO allows a UE to decide to perform handover if one or more handover execution conditions are met while in the legacy handover. A network (e.g., base station such as source gNB) makes the decision whether the handover should be performed or not. Herein, an execution condition related to the CHO may refer to CHO condition, or CHO execution condition.

[0177] For example, CHO procedure in the prior art may be described herein.

[0178] In CHO procedure, the followings are applied.

[0179] - The candidate target gNB(s) provide the CHO configuration to the source gNB, and the source gNB provides CHO configuration including one or more CHO configuration information of the candidate target gNB(s) to a UE. For exmaple, the CHO configuration provided to the UE includes the configuration of CHO candidate cell(s) generated by the candidate gNB(s) and execution condition(s) generated by the source gNB.

[0180] - The source gNB provides the one or more execution conditions to the UE.

[0181] - The trigger conditions(e.g., execution conditions) are configured based on signal quality measurements (e.g., RSRP, RSRQ, SINR, etc.). For example, the UE performs the measurements realted the signal quality and evaluate whether the one or more execution conditions are satisfied or not, based on the measurements.

[0182] - Upon receiving the CHO configuration, the UE starts evaluating the execution condition(s).

[0183] - If CHO or a legacy handover is executed, the UE stops evaluating the execution condition(s).

[0184] - If a source gNB receives Handover Success message from the target gNB, the source gNB sends the Handover Cancel message toward other potential target gNBs to cancel CHO for the UE.

[0185] The following drawings are intended to illustrate specific embodiments of the present disclosure. The designations of specific devices or the designations of specific signals / messages / fields shown in the drawings are for illustrative purposes only, and the technical features of the present specification are not limited to the specific designations used in the drawings below.

[0186] FIGS. 7a and 7b illustrate an example of an overall CHO procedure according to one embodiment of the present disclosure.

[0187] FIGS. 7a and 7b depicts an overall CHO procedure.

[0188] For reference, a target gNB in FIG. 7a and FIG. 7b is one of a potential target gNB(s). The target gNB becomes target gNB based on steps 13 to 16.

[0189] 1. An AMF may transmit mobility control information to a source gNB.

[0190] 2. A UE may transmit measurement reports to the source gNB. The measurement reports may include a measurement report related to the target gNB and / or potential target gNB(s).

[0191] 3 and 4. The source gNB may transmit a handover request message to the target gNB and / or potential target gNB(s).

[0192] 5 and 6. The target gNB and / or potential target gNB(s) may perform admission control.

[0193] 7 and 8. The target gNB and / or potential target gNB(s) may transmit Handover request Acknowledge message to the source gNB. For example, the Handover request Acknowledge message may include CHO configuration for the target gNB and / or potential target gNB(s).

[0194] 9. The source gNB may transmit RRCReconfiguration message including CHO configuration to the UE.

[0195] 10. The UE may transmit RRCReconfigurationComplete message to the source gNB.

[0196] 11. The UE may evaluate CHO conditions.

[0197] 12. If one or more CHO conditions are mat, the UE may detach from a source cell. The UE may synchronise to the target cell.

[0198] 13. The UE may perform RACH procedure with the target gNB. For example, the UE may perform RACH procedure based on FIGS. 5a to 5e.

[0199] 14. The UE may transmit RRCReconfigurationComplete message to the target gNB.

[0200] 15. The target gNB may transmit Handover Success messsage to the source gNB.

[0201] 16. The source gNB may transmit SN Status Transfer message to the target gNB.

[0202] 17. The source gNB may transmit Handover Cancel meesage to potential target gNB(s).

[0203] CHO condition evaluation is described herein.

[0204] The source gNB may configure the UE with one or more candidate target gNB(s)' (e.g., cells') CHO configuration in the RRCReconfiguration message. For example, the one or more candidate target gNB(s) transmits the CHO configuration to the source gNB in step 7 and step 8. The source gNB transmits the RRCReconfiguration message including one or more candidate target gNB(s)' (e.g., cells') CHO configuration to the UE in step 9. The CHO execution condition is mapped to measurement identity because CHO is performed based on the signal measurement results. In other words, the only triggering condition of CHO is signal quality.

[0205] The UE evaluates the CHO execution condition of each configured candidate target cell. If multiple target cells meet the CHO execution condition, it is up to UE implementation to decide which target cell to select.

[0206] The CHO information (e.g., CHO ocnfiguration) is included in a RRCReconfiguration message with the following information. For example, the CHO information (e.g., CHO ocnfiguration) may include the following information. Basically, the CHO execution condition is configured using the legacy measurement mechanism, and to perfrom the handover, reconfiguration information of potential target RAN is pre-included. ConditionalReconfiguration-r16 in Table 3 is an example of CHO configuration.

[0207] ConditionalReconfiguration-r16 ::= SEQUENCE {attemptCondReconfig-r16 ENUMERATED {true} OPTIONAL, -- Cond CHOcondReconfigToRemoveList-r16 CondReconfigToRemoveList-r16 OPTIONAL, -- Need NcondReconfigToAddModLis-r16 CondReconfigToAddModList-r16 OPTIONAL, -- Need N...,[[scpac-ReferenceConfiguration-r18 SetupRelease {ReferenceConfiguration-r18} OPTIONAL, -- Need MservingSecurityCellSetId-r18 SecurityCellSetId-r18 OPTIONAL, -- Need Msk-CounterConfiguration-r18 SK-CounterConfiguration-r18 OPTIONAL -- Need M]]}CondReconfigToRemoveList-r16 ::= SEQUENCE (SIZE (1.. maxNrofCondCells-r16)) OF CondReconfigId-r16SK-CounterConfiguration-r18 ::= SEQUENCE {sk-CounterConfigToReleaseList-r18 SEQUENCE (SIZE (1..maxSecurityCellSet-r18)) OF SecurityCellSetId-r18 OPTIONAL, -- Need Nsk-CounterConfigToAddModList-r18 SEQUENCE (SIZE (1..maxSecurityCellSet-r18)) OF SK-CounterConfig-r18 OPTIONAL -- Need N}SK-CounterConfig-r18 ::= SEQUENCE {securityCellSetId-r18 SecurityCellSetId-r18,sk-CounterList-r18 SEQUENCE (SIZE (1..maxSK-Counter-r18)) OF SK-Counter}SecurityCellSetId-r18 ::= INTEGER (1.. maxSecurityCellSet-r18)CondReconfigToAddModList-r16 ::= SEQUENCE (SIZE (1.. maxNrofCondCells-r16)) OF CondReconfigToAddMod-r16CondReconfigToAddMod-r16 ::= SEQUENCE {condReconfigId-r16 CondReconfigId-r16,condExecutionCond-r16 SEQUENCE (SIZE (1..2)) OF MeasId OPTIONAL, -- Need McondRRCReconfig-r16 OCTET STRING (CONTAINING RRCReconfiguration) OPTIONAL, -- Cond condReconfigAdd...,[[condExecutionCondSCG-r17 OCTET STRING (CONTAINING CondReconfigExecCondSCG-r17) OPTIONAL -- Need M]],[[condExecutionCondPSCell-r18 SEQUENCE (SIZE (1..2)) OF MeasId OPTIONAL, -- Cond condReconfigCHO-WithSCGsubsequentCondReconfig-r18 SubsequentCondReconfig-r18 OPTIONAL, -- Need MsecurityCellSetId-r18 SecurityCellSetId-r18 OPTIONAL, -- Need Mscpac-ConfigComplete-r18 ENUMERATED {true} OPTIONAL -- Cond CPAC]]}CondReconfigExecCondSCG-r17 ::= SEQUENCE (SIZE (1..2)) OF MeasIdSubsequentCondReconfig-r18 ::= SEQUENCE {condExecutionCondToReleaseList-r18 CondExecutionCondToReleaseList-r18 OPTIONAL, -- Need NcondExecutionCondToAddModList-r18 CondExecutionCondToAddModList-r18 OPTIONAL, -- Need N...}CondExecutionCondToAddModList-r18 ::= SEQUENCE (SIZE (1.. maxNrofCondCells-r16)) OF CondExecutionCondToAddMod-r18CondExecutionCondToAddMod-r18 ::= SEQUENCE {subsequentCondReconfigId-r18 CondReconfigId-r16,subsequentCondExecutionCond-r18 SEQUENCE (SIZE (1..2)) OF MeasId OPTIONAL, -- Need MsubsequentCondExecutionCondSCG-r18 OCTET STRING (CONTAINING CondReconfigExecCondSCG-r17) OPTIONAL, -- Need M...}CondExecutionCondToReleaseList-r18 ::= SEQUENCE (SIZE (1.. maxNrofCondCells-r16)) OF Con

[0208] For Table 3, 3GPP TS 38.331 V18.4.0 may be referred.

[0209] CHO configuration may be transmitted to the UE via RRC signalling including ConditionalReconfiguration-r16 to deliver configuration of one or more candidate target cells. ConditionalReconfiguration-r16 may include condReconfigToAddModLis-r16. condReconfigToAddModLis-r16 may include condExecutionCond-r16. condExecutionCond-r16 may include one or more CHO execution conditions. As shown in Table 3, condExecutionCond-r16 is related to MeasId, which is a measurement ID. That is, the UE evaluates CHO execution conditions based on the signal quality, which is based on a measurement related to the measurement ID.

[0210] In the prior art, the legacy handover mechanisms including CHO only consider signal quality of a source cell and signal quality of the neighbouring cells to trigger handover procedure.

[0211] However, it has been discussed that connecting to a particular access technology would be better to satisfy service characteristics in some scenarios. For example, connecting to Geostationary Earth Orbit (GEO) satellite is efficient to retain stable coverage for service continuity while connecting to Low Earth Orbit (LEO) satellite is efficient for faster communication.

[0212] For example, in prior arts, a UE may perform the conditional handover. In conditional handover, the UE may determine when to perform a handover based on one or more handover execution conditions. However, a conventional conditional handover has a limitation in that it considers only signal strength. For example, when a UE using a service for which coverage is important detects a GEO satellite that is advantageous in terms of coverage and a LEO satellite that is advantageous in terms of delay, the UE may undesirably perform handover only to the LEO satellite having stronger signal strength. That is, when performing handover, the UE may need to consider not only signal strength but also an access type.

[0213] In this disclosure, the CHO mechanism may be enhanced to adapt the characteristics of the required services of the UE and perform the CHO procedure to access to a particular access technology more adequate to the required services of the UE.

[0214] For example, a UE may perform conditional handover (CHO). In a conditional handover, the UE may determine when to perform the handover based on one or more handover execution conditions. However, a conventional conditional handover has a limitation in that it considers only signal strength. For example, when a UE using a service for which coverage is important detects a GEO satellite that is advantageous in terms of coverage and a LEO satellite that is advantageous in terms of delay, the UE may be undesirably handed over only to the LEO satellite having stronger signal strength. That is, when performing a handover, the UE may need to consider not only signal strength but also other factors such as an access type.

[0215] In the present disclosure, a conditional handover method proposed in the present disclosure may refer to adaptive conditional handover (ACHO).

[0216] However, this is merely an example, and the scope of the present disclosure is not limited by the term "ACHO." For example, the conditional handover method proposed herein may also be referred to by various terms, such as a handover, service adaptive conditional handover, a mobility procedure, a conditional mobility procedure, an adaptive mobility procedure, or the like.

[0217] To implement the mechanism for service adaptive conditional handover (ACHO) enhancement, a UE receives one or more potential target access technologies information (e.g., access technologies supported by candidate target cell) from the source RAN. If the UE determines that connecting to another cell using different access technology is better for the characteristics of the required services, the UE detaches from the source RAN and synchronizes to the candidate target cell, which may provide better services to the UE.

[0218] To implement the method for performing the ACHO mechanism, the UE and the network may be optionally configured with the matching access technology (MAT) information. The MAT information may be included in ACHO configuration to determine the access technology (or the Radio Access Technology (RAT) type) associated with a particular service (e.g., Traffic descriptor, application identity, Single-Network Slice Selection Assistance Information (S-NSSAI), service type, service characteristics, etc.), and / or a particular UE type (e.g., IoT device, Vehicle, Robots, AR glasses, Smart phones, etc.).

[0219] The UE may be preconfigured with the MAT information or receive MAT information via signalling (e.g., NAS signalling, AS signalling, or short message) as a part of ACHO configuration.

[0220] In some embodiments, MAT information may be configured based on subscription policy, traffic load, local policy, and / or AI driven information regarding UE intent or UE preferred services.

[0221] In some embodiments, if the UE has preconfigured MAT information and the received MAT information from the network via signalling, the received MAT information via signalling may have priority.

[0222] ACHO configurations may inlcude at least one of the followings:

[0223] - Handover execution conditions (e.g., ACHO execution conditions);

[0224] - Assistance information (e.g., MAT information, frequency information). For reference, the MAT information may be included in the assistance information, and / or the MAT information may be transmitted independently to the UE as step 4 in FIG.10a. For example, the MAT information may include satellite NR, and the frequency information may include a first frequency that can be used for the satellite NR. In this case, the UE may select a cell using the satellite NR and may used the first frequency; and / or

[0225] - Candidate target cell configurations (e.g., information related to synchronization with target cell information, and / or Configuraiton information such as the reconfiguration information of target cell).

[0226] The MAT information may include one or more of: information related to {one or more allowed access technologies and a service}, information related to {restricted one or more access technologies and a service}, information related to {i) at least one of allowed access technology, default access technology, preferred access technology, and / or restricted access technology and ii) a service} and / or information related to {default access technology for a service type or a UE type}. For example, the UE may be configured with the following example configurations(e.g., the MAT information or the mapping information included in the MAT information):

[0227] - The MAT information includes the mapping information based on {restricted one or more access technologies and a service}. For example, restricted one or more access technologies may be GEO satellite and the service may be delay sensitive services. For example, the mapping information may include that GEO satellite is a restricted access technology for delay sensitive services.

[0228] - The MAT information includes the mapping information based on {default access technology for a service type or a UE type}. For example, default access technology may be GEO satellite and the service type may be services requiring coverage retainability. For example, the mapping information may include that GEO satellite is a default access technology for services requiring coverage retainability,

[0229] - The MAT information includes the mapping information based on {restricted one or more access technologies and a service}. For example, restricted one or more access technologies may be GEO satellite and the service may be delay sensitive services. For example, the mapping information may include that LEO or low altitude aerial devices (e.g., UAVs) is a restricted access technology for services requiring coverage retainability.

[0230] - The MAT information includes the mapping information based on {i) at least one of default access technology, preferred access technology, and / or restricted access technology and ii) a service}. For example, default access technology is GEO for the specific service type (e.g., service type-1), preferred access technology is GEO, MEO, TN for service type-1, restricted access technology is LEO, UAV for the specific service type (e.g., service tpye-1). For example, For example, the mapping information may include that for the specific service type (e.g., Service type-1): Default: GEO, Preferred: GEO, MEO, TN, Restricted: LEO, UAV.

[0231] In some embodiments, the MAT information may have a list of service priority so that the access technology of higher priority service is selected.

[0232] In some embodiments, the ACHO mechanism is introduced based on the following principles:

[0233] - The signal quality of a target cell should be above a threshold. For example, the UE may perform a measurement for the target cell. If the signal quality of a target cell is above the threshold, the UE may evaluate ACHO condition for the target cell.

[0234] - If the UE fails ACHO execution, the UE may perform CHO.

[0235] - If CHO configuration and ACHO configuration is separate configuration each other, and if the UE has both CHO configuration and ACHO configurations, ACHO configuration has priority. For example, the UE may receive a RRC message including ACHO configuration information. The RRC message may include one or more handover configurations (e.g., CHO configuration and / or ACHO configuration), one or more handover execution condition (e.g. MeasId to detect A3 / A5 event), one or more lists including candidate target cells where the list is associated with the handover configuration.

[0236] - ACHO configurations may include delta of (e.g., different information from) CHO configurations. When the UE selects a target cell during handover, the ACHO configuration has priority. For example, the UE may receive delta ACHO configuration (e.g., supported access technology of a candidate target cell) of CHO configuration, and the delta may be a list of preferred access technology information. In this example scenario, the UE may perform legacy conditional handover procedure considering the delta ACHO information, which is preferred access technology information, to determine the target cell.

[0237] The ACHO execution conditions may incldue legacy CHO execution conditions. In addition to the legacy CHO execution conditions, ACHO execution conditions to be evaluated by the UE may include at least one of:

[0238] - Protocol Data Unit (PDU) session establishment initiation or PDU session modification procedure initiation;

[0239] - User data of a new traffic type. User data of a new traffic type means that no associated PDU session has been established yet;

[0240] - Mobile originated signalling; and / or

[0241] - UE mode changes (e.g., data store and forward mode, voice-centric mode, etc)

[0242] - signal quality of the serving cell and / or neighbour cells (e.g., B1 event, B2 event specified in TS 38.331 V18.4.0).

[0243] If the UE evaluates that one or more of the ACHO execution conditions are satisfied, the UE may perform operations related to ACHO.

[0244] In some embodiments, the UE may receive the reconfiguration information of the potential target RAN with the access technology information as ACHO configuration. For example, the reconfiguration information may be an example of the ACHO configuration For example, the reconfiguration information may be based on Table 4.

[0245] ACondReconfigToAddModList-r16 ::= SEQUENCE (SIZE (1.. maxNrofCondCells-r16)) OF ACondReconfigToAddMod-r16ACondReconfigToAddMod-r16 ::= SEQUENCE {condReconfigId-r16 CondReconfigId-r16,targetAT-Type ENUMERATED { nr, nr(GEO), nr(MEO), nr(LEO), eutra, eutra(LEO), non-3gpp, ...},condRRCReconfig-r16 OCTET STRING (CONTAINING RRCReconfiguration) OPTIONAL, -- Cond condReconfigAdd...,[[condExecutionCondSCG-r17 OCTET STRING (CONTAINING CondReconfigExecCondSCG-r17) OPTIONAL -- Need M]],[[condExecutionCondPSCell-r18 SEQUENCE (SIZE (1..2)) OF MeasId OPTIONAL, -- Cond condReconfigCHO-WithSCGsubsequentCondReconfig-r18 SubsequentCondReconfig-r18 OPTIONAL, -- Need MsecurityCellSetId-r18 SecurityCellSetId-r18 OPTIONAL, -- Need Mscpac-ConfigComplete-r18 ENUMERATED {true} OPTIONAL -- Cond CPAC]]}

[0246] ACondReconfigToAddModList-r16 may contain ACHO configuration information of one or more candidate target cells. condReconfigId-r16 may mean the identity to distinguish each candidate target cell ACHO configuration. targetAT-Type may mean target access technology type supported by the candidate target cell. condRRCReconfig-r16 may mean RRCReconfiguration information to synchronize with the candidate target cell. condExecutionCondSCG-r17 may mean the CHO execution condition to perform ACHO towards the candidate target cell. securityCellSetId-r18 may be used determine whether the UE should perform security update when ACHO is executed.

[0247] According to Table 8, the reconfiguration information may include ACondReconfigToAddModList-r16. ACondReconfigToAddModList-r16 may include ACondReconfigToAddMod-r16. ACondReconfigToAddMod-r16 may include targetAT-Type may include at least one of nr, nr(GEO), nr(MEO), nr(LEO), eutra, eutra(LEO), non-3gpp, ....

[0248] For example, the UE may receive targetAT-Type of one or more of potential target gNB(s). To select a target cell supporting a access technology that the UE wants to use, the UE may select the target cell based on the targetAT-Type of one or more of potential target gNB(s).

[0249] FIG. 8 depicts the example ACHO decision flow.

[0250] The following drawings are intended to illustrate specific embodiments of the present disclosure. The designations of specific devices or the designations of specific signals / messages / fields shown in the drawings are for illustrative purposes only, and the technical features of the present specification are not limited to the specific designations used in the drawings below.s

[0251] FIG. 8 illustrates an example of operations related to ACHO performed by a UE according to one embodiment of the present disclosure.

[0252] In step S801, the UE may evaluate ACHO execution conditions.

[0253] For example, the ACHO execution condition may include at least one of:

[0254] - PDU session establishment initiation or PDU session modification procedure initiation;

[0255] - User data of a new traffic type. User data of a new traffic type means that no associated PDU session has been established yet;

[0256] - Mobile originated signalling; and / or

[0257] - UE mode changes (e.g., data store and forward mode, voice-centric mode, etc).

[0258] In step S802, the UE may determine whether any ACHO execution condition is satisfied. If any ACHO execution condition is satisfied, step S803 may be performed. If none of ACHO execution condition is satisfied, the UE may evaluate CHO execution conditions.

[0259] In step S803, the UE may determine a target cell, based on ACHO assistance information.

[0260] For exampel, the ACHO assitance information may include MAT information, and / or frequency information.

[0261] In step S804, the UE may detach from a source cell. The UE may synchoronize to the target cell.

[0262] In some embodiments, examples of the UE operation may be described as follows.

[0263] i) The UE is in a terrestrial network (TN) cell.

[0264] ii) The UE may receive ACHO configurations from a source cell.

[0265] iii) The UE evaluates ACHO execution conditions.

[0266] iv) The UE changes its mode to voice-centric.

[0267] v) If the serving cell does not support IMS or the cell signal quality(e.g., cell signal quality of the serving cell) is below the threshold in the ACHO configurations, the UE determines the target cell based on ACHO configurations.

[0268] vi) Based on the ACHO configurations, the UE selects a cell supporting IMS and the signal quality is higher than the threshold to receive IMS services.

[0269] vii) The UE executes ACHO to the selected target cell, detach from the source cell and synchronize to the target cell.

[0270] The following drawings are intended to illustrate specific embodiments of the present disclosure. The designations of specific devices or the designations of specific signals / messages / fields shown in the drawings are for illustrative purposes only, and the technical features of the present specification are not limited to the specific designations used in the drawings below.

[0271] FIG. 9 illustrates an example in which a UE performs operations related to ACHO and / or CHO according to one embodiment of the present disclosure.

[0272] In step S901, the UE determines whether any ACHO condition (e.g., ACHO execution condition) is satisfied or not. If any ACHO condition is satisfied, step S902 is performed. If any ACHO condition is not satisfied, step S904 is performed.

[0273] In step S902, the UE may select the adequate access technology based on MAT information. The UE may check if the signal quality of the selected target cell is good enough (e.g., the signal quality of the selected target cell is greater than a threshold). The UE may select a target cell based on MAT information. If step S902 succeded, step S903 is performed. If step S902 fails (e.g., if the UE fails to select the adequate access technology, and / or if the signal quality of the selected target cell is not good enough), step S903 is performed.

[0274] In step S903, the UE may detach from a source cell. The UE may synchronise to the target cell.

[0275] In step S904, the UE may evaluate CHO conditions.

[0276] In step S905, if one or more CHO conditions are met, the UE may check MAT information for the existing ongoing services. If the access technology supported in the candidate target cell is not matched based on MAT information, the UE may perform another CHO procedure. If the candidate target cell in the 2ndround is also not matched based on MAT information, the UE may selected the candidate target cell as a suiable cell without further CHO execution. In some embodiments, checking the MAT information may be skipped in step S905. If the access technology of the candidate target RAN (e.g., target cell) is allowable, the UE may detach from the source cell, and synchronise to the target cell.

[0277] Example operations according to implementations of the present disclosure may be as follows as presented in FIGS. 10a and 10b.

[0278] The following drawings are intended to illustrate specific embodiments of the present disclosure. The designations of specific devices or the designations of specific signals / messages / fields shown in the drawings are for illustrative purposes only, and the technical features of the present specification are not limited to the specific designations used in the drawings below.

[0279] FIGS. 10a and 10b illustrate an example of a procedure according to one embodiment of the present disclosure.

[0280] Step 1. The UE may be preconfigured with the MAT information. Step 1 can be optional. For example, the UE may receive the MAT information in step 4.

[0281] The network may store the MAT information. The core network (e.g., AMF) may provide the MAT information to a source RAN so that the source RAN maintains the UE context with the MAT information and uses it for handover, roaming, and / or access restrictions.

[0282] Step 2. The UE may send the UE capability indication (or information) to indicate that the UE supports ACHO mechanism to the network.

[0283] For example, the UE capability indication may be transmitted via RRC message. The RAN node may deliver this capability indication to the core network (e.g., AMF).

[0284] For example, the UE capability indication may be transmitted via NAS message (e.g., 5GMM capability information in a registration request message).

[0285] Step 3 and step 4. The network may provide MAT information to the source RAN and / or the UE.

[0286] For example, the AMF may transmit mobility control information including MAT information or the mobility information with the MAT inforation to the source gNB. Upon reception of MAT information, the source RAN may update the UE mobility information (e.g., mobility restrictions) in the UE context.

[0287] For example, the AMF or the source gNB may tranmsit the MAT information to the UE. Upon reception of MAT information, the UE may store the MAT information in a non-volatile memory (NVM). The stored MAT information may be deleted when the UE leaves the registration area, tracking area or the PLMN.

[0288] Step 4 may be optional. For exmaple, the UE may be preconfigured with the MAT information in step 1.

[0289] Step 5 and step 6. The source RAN may send a handover request message to one or more potential target RAN.

[0290] For example, the source RAN may include the ACHO indication in the handover request message to distinguish the handover request from the legacy handover request.

[0291] Step 7 and step 8. Admission control is performed in the target RAN(e.g., gNB) and the potential target RAN(e.g., gNB).

[0292] Step 9 and Step 10. If the handover request is permitted, the potential target RAN send back the handover request acknowledge message including the configuration of the candidate cell to the source RAN. If the handover request is not permitted (e.g., due to workload), the potential target RAN may send back the reject response to the source RAN.

[0293] Step 11. The source RAN sends the ACHO configuration information to the UE.

[0294] For example, the ACHO configuration information may include at least one of: Handover execution conditions, Assistance information (e.g. MAT information, frequency information), and / or Candidate target cell configurations.

[0295] For example, the source RAN may send a RRC reconfiguration message including the ACHO configuration information to the UE. For exaple, the ACHO configuration of potential target cells can be followed by reconfiguration of the source RAN.

[0296] Step 12. The UE sends the response message (e.g., RRCReconfigurationComplete message) to the network upon reception of the ACHO configuration information.

[0297] For example, the UE may send a RRC reconfiguration complete message as the response message.

[0298] Step 13 and step 14: The UE may evaluate ACHO conditions(e.g., ACHO execution conditions). If any ACHO triggering condition is met, the UE may select an adequate cell for the required service characteristics. The UE may refer the stored MAT information to select the cell. For example, the UE may select a target cell based on MAT information and the siganl quality of target gNB and / or potential target gNB(s). The UE may detach from the source cell and synchronise to the target cell.

[0299] For example, the UE may initiate a new PDU session establishment procedure, which is one of ACHO conditions. That is, one or more of ACHO conditions is met in this case. Then, the UE first check the current access technology that the UE is connected to is adequate to the required service characteristics, based on the MAT information. If not, the UE select another cell for an appropriate access technology.

[0300] For example, the MAT information may include mapping information that LEO satellite is allowable for an emergency PDU session. In this case, if the UE is connected to GEO satellite and an emergency PDU session needs to be established, the UE may select a cell to connect to LEO satellite for the emergency service.

[0301] Step 15: The UE performs a RACH procedure to synchronise to a target cell.

[0302] For example, the UE may perform the RACH procedure to synchronise to the target cell, based on examples of FIGS. 5a to 5e.

[0303] Step 16: If the RACH procedure in Step 8 successfully completes, the UE may send a RRC reconfiguration complete message to the target cell.

[0304] If the ACHO procedure fails, the UE may fall back to legacy operations (e.g., legacy operations without considering ACHO or MAT information).

[0305] Step 17 and step 18 The target RAN sends Handover success message to the source RAN. The source RAN sends SN Status Transfer to the target RAN and Handover success indication to other potential target RAN(s).

[0306] Step 19: The source RAN may transmit handover success indication to the potential target RAN. The potential target RAN that receives Handover success indication may cancel the CHO for the UE.

[0307] The following drawings are intended to illustrate specific embodiments of the present disclosure. The designations of specific devices or the designations of specific signals / messages / fields shown in the drawings are for illustrative purposes only, and the technical features of the present specification are not limited to the specific designations used in the drawings below.

[0308] FIG. 11 illustrates an example of an operation according to an embodiment of the present disclosure.

[0309] In addition, the operation of a UE and a base station (e.g., cell or gNB) shown in the example of FIG. 11 is only an example. The operation of the UE is not limited by the example of FIG. 11, and the UE and the base station may perform the operations described in various examples of the present specification.

[0310] In step S1101, the base station may transmit a configuration message to a UE.

[0311] For example, the configuration message includes information related to mobility procedure based on an access type. The information related to mobility procedure based on the access type includes information related to at least one execution condition.

[0312] For example, the mobility procedure may include a handover.

[0313] For example, information related to mobility procedure based on an access type may be ACHO configuration in examples of the present disclsoure.

[0314] In step S1102, the UE may transmit response message to the base station.

[0315] In step S1103, the UE may select a cell. For example, the UE may select a target cell.

[0316] For example, based on that one or more conditions of the at least one execution condition are satisfied, the UE may select a target cell, based on mapping information related to an access technology and a service type.

[0317] In some embodiments, the mapping information related to an access technology and a service type may be MAT information in the examples of the present disclosure.

[0318] In some embodiments, the information related to mobility procedure based on the access type further includes at least one of: assistance information, or information related to at least one candidate target cell.

[0319] In some embodiments, the mapping information related the access technology and the service type includes at least one of: i) information related to the service type, and information related to one or more allowed access technologies related to the service type; ii) information related to the service type, and information related to one or more restricted access technologies related to the service type; iii) information related to the service type, and information related to one or more default access technologies related to the service type; or iv) information related to the service type, and at least one of the information related to the one or more allowed access technologies related to the service type, the information related to the one or more restricted access technologies related to the service type, the information related to the one or more default access technologies related to the service type, or information related to one or more preferred access technologies related to the service type.

[0320] In some embodiments, the mapping information related the access technology and the service type is preconfigured in the UE or is received from the first base station.

[0321] In some embodiments, the the information related to at least one execution condition includes one or more of a condition related to data session establishment procedure initiation or data session modification procedure initiation, a condition related to user data for a new traffic type, a condition related to mobil originated signalling, or a condition related to a change of a UE mode.

[0322] In some embodiments, the UE may transmit access information (e.g., a random access preamble) to the target cell. The UE may receive a response message from the target cell.

[0323] In some embodiments, the UE may receive, from a base station (BS), service aware conditional handover information (e.g., ACHO configuration) including access technology information (e.g., MAT information) and potential target BSs.

[0324] In some embodiments, the UE may determine whether any ACHO execution condition is satisfied. For example, if the UE may detect a mobile originated transmission, the UE determisn that ACHO execution condition is satisfied.

[0325] In some embodiments, the UE may execute service aware conditional handover(e.g., ACHO).

[0326] In some embodiments, the UE and / or the source cell may inform a successful handover to potential target BSs, if the service aware conditional handover(e.g., ACHO) successfully completes.

[0327] The present specification may have various effects.

[0328] For example, a mobility procedure (e.g., handover) based on the UE's service may be effectively supported. For example, a mobility procedure (e.g., handover) based on an access type and / or an access technology may be supported.

[0329] For example, when multiple good-quality cells supporting different access technologies are available, the UE may perform conditional handover to a cell that is suitable for the service preferred by the UE. In addition, unnecessary subsequent mobility operations may be reduced, and fast mobility support may help ensure the quality of service provided to the UE.

[0330] For example, the UE decides to perform handover to select an appropriate access technology considering the characteristics of the required services. Examples of the present disclosure is beneficial in that the UE can immediately react to select better access technology when a new type of service is required.

[0331] The effects that may be obtained from the specific examples of this disclosure are not limited to those listed above. For example, there may be a variety of technical effects that a person having ordinary skill in the related art may understand or infer from this disclosure. Accordingly, the specific effects of the present disclosure are not limited to those expressly set forth herein, but may include a variety of effects that may be understood or inferred from the technical features of the present disclosure.

[0332] For reference, the operation of the terminal (e.g., UE) described in the present specification may be implemented by the apparatus of FIGS. 1 to 4 described above. For example, the terminal (e.g., UE) may be the first device 100 or the second device 200 of FIG. 2. For example, an operation of a terminal (e.g., UE) described herein may be processed by one or more processors 102 or 202 . The operation of the terminal described herein may be stored in one or more memories 104 or 204 in the form of an instruction / program (e.g., instruction, executable code) executable by one or more processors 102 or 202 . One or more processors 102 or 202 control one or more memories 104 or 204 and one or more transceivers 105 or 206, and may perform the operation of the terminal (e.g., UE) described herein by executing instructions / programs stored in one or more memories 104 or 204.

[0333] In addition, instructions for performing an operation of a terminal (e.g., UE) described in the present disclosure of the present specification may be stored in a non-volatile computer-readable storage medium in which it is recorded. The storage medium may be included in one or more memories 104 or 204 . And, the instructions recorded in the storage medium may be executed by one or more processors 102 or 202 to perform the operation of the terminal (e.g., UE) described in the present disclosure of the present specification.

[0334] For reference, the operation of a network node (e.g., AMF, SMF, UPF, PCF, UDM, etc.) or base station (e.g., NG-RAN, gNB, target gNB, source gNB, potential target gNB, source cell, target cell, eNB, RAN, E-UTRAN etc.) described herein may be implemented by the apparatus of FIGS. 1 to 3 to be described below. For example, a network node or a base station may be the first device 100 of FIG.2 or the second device 200 of FIG.2. For example, the operation of a network node or base station described herein may be processed by one or more processors 102 or 202. The operation of the terminal described herein may be stored in one or more memories 104 or 204 in the form of an instruction / program (e.g., instruction, executable code) executable by one or more processors 102 or 202. One or more processors 102 or 202 may perform the operation of a network node or a base station described herein, by controlling one or more memories 104 or 204 and one or more transceivers 106 or 206 and executing instructions / programs stored in one or more memories 104 or 204.

[0335] In addition, instructions for performing the operation of the network node or base station described in the present disclosure of the present specification may be stored in a non-volatile (or non-transitory) computer-readable storage medium. The storage medium may be included in one or more memories 104 or 204. And, the instructions recorded in the storage medium are executed by one or more processors 102 or 202, so that the operations of a network node or base station are performed.

[0336] In the above, preferred embodiments have been exemplarily described, but the present disclosure of the present specification is not limited to such specific embodiments, and thus, modifications, changes, or may be improved.

[0337] In the exemplary system described above, the methods are described on the basis of a flowchart as a series of steps or blocks, but are not limited to the order of the steps described, some steps may occur in a different order or concurrent with other steps as described above. In addition, those skilled in the art will understand that the steps shown in the flowchart are not exclusive and that other steps may be included or that one or more steps of the flowchart may be deleted without affecting the scope of rights.

[0338] The claims described herein may be combined in various ways. For example, the technical features of the method claims of the present specification may be combined and implemented as an apparatus, and the technical features of the apparatus claims of the present specification may be combined and implemented as a method. In addition, the technical features of the method claim of the present specification and the technical features of the apparatus claim may be combined to be implemented as an apparatus, and the technical features of the method claim of the present specification and the technical features of the apparatus claim may be combined and implemented as a method.

Claims

1.A method comprising:receiving, by a User Equipment (UE) from a first base station, a configuration message,wherein the configuration message includes information related to mobility procedure based on an access type,wherein the information related to mobility procedure based on the access type includes information related to at least one execution condition;transmitting, by the UE to the first base station, a response message; andbased on that one or more conditions of the at least one execution condition are satisfied, selecting a target cell, based on information related to an access technology.2.The method of claim 1,wherein the information related to mobility procedure based on the access type further includes at least one of: assistance information, or information related to at least one candidate target cell.3.The method of claim 1 or 2,wherein the information related to the access technology includes mapping information related to the access technology and a service type.4.The method of claim 3, wherein the mapping information related the access technology and the service type includes at least one of:i) information related to the service type, and information related to one or more allowed access technologies related to the service type;ii) information related to the service type, and information related to one or more restricted access technologies related to the service type;iii) information related to the service type, and information related to one or more default access technologies related to the service type; oriv) information related to the service type, and at least one of the information related to the one or more allowed access technologies related to the service type, the information related to the one or more restricted access technologies related to the service type, the information related to the one or more default access technologies related to the service type, or information related to one or more preferred access technologies related to the service type.5.The method of any one of claims 1 to 4,wherein the information related to the access technology is preconfigured in the UE or is received from the first base station.6.The method of any one of claims 1 to 5, further comprising:wherein the information related to at least one execution condition includes one or more of a condition related to data session establishment procedure initiation or data session modification procedure initiation, a condition related to user data for a new traffic type, a condition related to mobil originated signalling, or a condition related to a change of a UE mode.7.The method of any one of claims 1 to 6, further comprising:transmitting access information to the target cell; andreceiving a response message from the target cell.8.A user equipment (UE) comprising:at least one transceiver;at least one processor; andat least one memory that stores instructions and is operably electrically connectable with the at least one processor,wherein operations performed based on the instructions being executed by the at least one processor include method of claims 1 to 7.9.An apparatus performing communication, comprising:at least one processor; andat least one memory storing instructions, operatively electrically coupled to the at least one processor, wherein the instructions are executed by the at least one processor to perform operations comprising method of claims 1 to 7.10.A non-transitory computer readable storage medium recording instructions,wherein the instructions, when executed by one or more processors, causing the one or more processors to perform operations compirsing method of claims 1 to 7.11.A method comprising:transmitting, by a first base station to a User Equipment (UE), a configuration message,wherein the configuration message includes information related to mobility procedure based on an access type,wherein the information related to mobility procedure based on the access type includes information related to at least one execution condition; andreceiving, by first base station from the UE, a response message,based on that one or more conditions of the at least one execution condition are satisfied, a target cell is selected by the UE, based on information related to an access technology.12.The method of claim 11,wherein the information related to mobility procedure based on the access type further includes at least one of: assistance information, or information related to at least one candidate target cell.13.The method of claim 11 or 12,wherein the information related to the access technology includes mapping information related to the access technology and a service type.14.The method of claim 13, wherein the mapping information related the access technology and the service type includes at least one of:i) information related to the service type, and information related to one or more allowed access technologies related to the service type;ii) information related to the service type, and information related to one or more restricted access technologies related to the service type;iii) information related to the service type, and information related to one or more default access technologies related to the service type; oriv) information related to the service type, and at least one of the information related to the one or more allowed access technologies related to the service type, the information related to the one or more restricted access technologies related to the service type, the information related to the one or more default access technologies related to the service type, or information related to one or more preferred access technologies related to the service type.15.The method of any one of claims 10 to 12,wherein the information related to the access technology is preconfigured in the UE or is transmitted by the first base station to the UE.16.The method of any one of claims 11 to 15, further comprising:wherein the information related to at least one execution condition includes one or more of a condition related to data session establishment procedure initiation or data session modification procedure initiation, a condition related to user data for a new traffic type, a condition related to mobil originated signalling, or a condition related to a change of a UE mode.17.A base station comprising:at least one transceiver;at least one processor; andat least one memory that stores instructions and is operably electrically connectable with the at least one processor,wherein operations performed based on the instructions being executed by the at least one processor include method of claim 11 to claim 16.

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