Mobility information logging in wireless communications

Abstract

The present disclosure is related to mobility information logging in wireless communications. According to an embodiment of the present disclosure, a communication device may, after a mobility procedure ends, transmit mobility information comprising: first information for an execution condition that is satisfied first among a first execution condition for a primary cell (PCell) mobility to a target PCell and a second execution condition for a primary secondary cell (PSCell) mobility to a target PSCell associated with the target PCell; and second information for a time duration that has elapsed since the execution condition was satisfied.

Description

MOBILITY INFORMATION LOGGING IN WIRELESS COMMUNICATIONS

[0001] The present disclosure is related to mobility information logging in wireless communications.

[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] In wireless communications, a communication device may log mobility information after a mobility procedure ends in failure or success. The communication device may report the logged mobility information to a network, and the network may use the reported mobility information for various purposes, including a mobility configuration for another mobility.

[0006] An aspect of the present disclosure is to provide method and apparatus for mobility information logging in a wireless communication system.

[0007] According to an embodiment of the present disclosure, a method performed by a communication device adapted to operate in a wireless communication system comprises: receiving a conditional reconfiguration comprising execution conditions for mobility including i) a first execution condition for a PCell mobility to a target PCell, and ii) a second execution condition for a PSCell mobility to a target PSCell associated with the target PCell; evaluating the execution conditions including the first execution condition for the target PCell and the second execution condition for the associated target PSCell; performing a mobility procedure based on one or more execution conditions among the execution conditions being satisfied; and after the mobility procedure ends, transmitting mobility information comprising: first information for an execution condition that is satisfied first among the first execution condition and the second execution condition; and second information for a time duration that has elapsed since the execution condition was satisfied.

[0008] According to an embodiment of the present disclosure, a method performed by a network node configured to operate in a wireless communication system comprises: transmitting, to a communication device, a measurement configuration; receiving, from the communication device, a measurement report; and transmitting, to the communication device, a conditional reconfiguration comprising execution conditions for mobility including i) a first execution condition for a PCell mobility to a target PCell, and ii) a second execution condition for a PSCell mobility to a target PSCell associated with the target PCell, wherein the communication device is adapted to perform operations comprising: evaluating the execution conditions including the first execution condition for the target PCell and the second execution condition for the associated target PSCell; performing a mobility procedure based on one or more execution conditions among the execution conditions being satisfied; and after the mobility procedure ends, transmitting mobility information comprising: first information for an execution condition that is satisfied first among the first execution condition and the second execution condition; and second information for a time duration that has elapsed since the execution condition was satisfied.

[0009] According to various embodiments, apparatuses to implement the above methods are provided.

[0010] The present disclosure may have various advantageous effects.

[0011] For example, network can update CPA / CPC information for other UEs in similar situations to more appropriately apply the CPA / CPC configuration. This can prevent mobility failures from other UEs caused by the same reason in the future.

[0012] For example, the network can consider information regarding CPA / CPC configuration which is associated with CHO configuration when the UE successfully performs PCell mobility. Therefore, the network can update and provide the CPA / CPC configuration more appropriately to other UEs in similar situations to prevent SCG failure cases or additional PSCell changes to find a better PSCell.

[0013] Advantageous effects which can be obtained through specific embodiments of the present disclosure are not limited to the advantageous effects listed above. For example, there may be a variety of technical effects that a person having ordinary skill in the related art can understand and / or derive from the present disclosure. Accordingly, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that may be understood or derived from the technical features of the present disclosure.

[0014] FIG. 1 shows an example of a communication system to which implementations of the present disclosure is applied.

[0015] FIG. 2 shows an example of wireless devices to which implementations of the present disclosure is applied.

[0016] FIG. 3 shows an example of UE to which implementations of the present disclosure is applied.

[0017] FIGs. 4 and 5 show an example of protocol stacks in a 3GPP based wireless communication system to which implementations of the present disclosure is applied.

[0018] FIG. 6 shows a frame structure in a 3GPP based wireless communication system to which implementations of the present disclosure is applied.

[0019] FIG. 7 shows a data flow example in the 3GPP NR system to which implementations of the present disclosure is applied.

[0020] FIG. 8 shows an example of a dual connectivity (DC) architecture to which technical features of the present disclosure can be applied.

[0021] FIG. 9 shows an example of a conditional mobility procedure according to an embodiment of the present disclosure.

[0022] FIG. 10 shows an example of a method performed by a communication device according to an embodiment of the present disclosure.

[0023] FIG. 11 shows an example of a signal flow between a communication device and a network node according to an embodiment of the present disclosure.

[0024] FIG. 12 shows an example of a procedure for logging of mobility information after the mobility failure according to an embodiment of the present disclosure.

[0025] FIG. 13 shows an example of a procedure for logging of mobility information after the mobility failure according to an embodiment of the present disclosure.

[0026] 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).

[0027] 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.

[0028] 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.

[0029] 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".

[0030] 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".

[0031] 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".

[0032] 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".

[0033] 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".

[0034] Technical features that are separately described in one drawing in the present disclosure may be implemented separately or simultaneously.

[0035] 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.

[0036] 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.

[0037] FIG. 1 shows an example of a communication system to which implementations of the present disclosure is applied.

[0038] 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.

[0039] 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).

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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).

[0048] Frequency Range designationCorresponding frequency rangeSubcarrier SpacingFR1450MHz - 6000MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0049] 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).

[0050] Frequency Range designationCorresponding frequency rangeSubcarrier SpacingFR1410MHz - 7125MHz15, 30, 60kHzFR224250MHz - 52600MHz60, 120, 240kHz

[0051] 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.FIG. 2 shows an example of wireless devices to which implementations of the present disclosure is applied.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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).

[0068] 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.

[0069] 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.

[0070] 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.

[0071] In the present disclosure, a BS is also referred to as a node B (NB), an eNode B (eNB), or a gNB.

[0072] FIG. 3 shows an example of UE to which implementations of the present disclosure is applied.

[0073] Referring to FIG. 3, a UE 100 may correspond to the first wireless device 100 of FIG. 2.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] FIGs. 4 and 5 show an example of protocol stacks in a 3GPP based wireless communication system to which implementations of the present disclosure is applied.

[0083] In particular, FIG. 4 illustrates an example of a radio interface user plane protocol stack between a UE and a BS and FIG. 5 illustrates an example of a radio interface control plane protocol stack between a UE and a BS. The control plane refers to a path through which control messages used to manage call by a UE and a network are transported. The user plane refers to a path through which data generated in an application layer, for example, voice data or Internet packet data are transported. Referring to FIG. 4, the user plane protocol stack may be divided into Layer 1 (L1, for example PHY layer) and Layer 2 (L2, for example MAC / RLC / PDCP layer). Referring to FIG. 5, the control plane protocol stack may be divided into Layer 1 (L1, for example PHY layer), Layer 2 (L2, for example MAC / RLC / PDCP layer), Layer 3 (L3, for example an RRC layer), and a non-access stratum (NAS) layer. Layer 1, Layer 2 and Layer 3 are referred to as an access stratum (AS).

[0084] In the 3GPP LTE system, the Layer 2 is split into the following sublayers: MAC, RLC, and PDCP. In the 3GPP NR system, the Layer 2 is split into the following sublayers: MAC, RLC, PDCP and SDAP. The PHY layer offers to the MAC sublayer transport channels, the MAC sublayer offers to the RLC sublayer logical channels, the RLC sublayer offers to the PDCP sublayer RLC channels, the PDCP sublayer offers to the SDAP sublayer radio bearers. The SDAP sublayer offers to 5G core network quality of service (QoS) flows.

[0085] In the 3GPP NR system, the main services and functions of the MAC sublayer include: mapping between logical channels and transport channels; multiplexing / de-multiplexing of MAC SDUs belonging to one or different logical channels into / from transport blocks (TB) delivered to / from the physical layer on transport channels; scheduling information reporting; error correction through hybrid automatic repeat request (HARQ) (one HARQ entity per cell in case of carrier aggregation (CA)); priority handling between UEs by means of dynamic scheduling; priority handling between logical channels of one UE by means of logical channel prioritization; padding. A single MAC entity may support multiple numerologies, transmission timings and cells. Mapping restrictions in logical channel prioritization control which numerology(ies), cell(s), and transmission timing(s) a logical channel can use.

[0086] Different kinds of data transfer services are offered by MAC. To accommodate different kinds of data transfer services, multiple types of logical channels are defined, i.e., each supporting transfer of a particular type of information. Each logical channel type is defined by what type of information is transferred. Logical channels are classified into two groups: control channels and traffic channels. Control channels are used for the transfer of control plane information only, and traffic channels are used for the transfer of user plane information only. Broadcast control channel (BCCH) is a downlink logical channel for broadcasting system control information, paging control channel (PCCH) is a downlink logical channel that transfers paging information, system information change notifications and indications of ongoing public warning service (PWS) broadcasts, common control channel (CCCH) is a logical channel for transmitting control information between UEs and network and used for UEs having no RRC connection with the network, and dedicated control channel (DCCH) is a point-to-point bi-directional logical channel that transmits dedicated control information between a UE and the network and used by UEs having an RRC connection. Dedicated traffic channel (DTCH) is a point-to-point logical channel, dedicated to one UE, for the transfer of user information. A DTCH can exist in both uplink and downlink. In downlink, the following connections between logical channels and transport channels exist: BCCH can be mapped to broadcast channel (BCH); BCCH can be mapped to downlink shared channel (DL-SCH); PCCH can be mapped to paging channel (PCH); CCCH can be mapped to DL-SCH; DCCH can be mapped to DL-SCH; and DTCH can be mapped to DL-SCH. In uplink, the following connections between logical channels and transport channels exist: CCCH can be mapped to uplink shared channel (UL-SCH); DCCH can be mapped to UL-SCH; and DTCH can be mapped to UL-SCH.

[0087] The RLC sublayer supports three transmission modes: transparent mode (TM), unacknowledged mode (UM), and acknowledged node (AM). The RLC configuration is per logical channel with no dependency on numerologies and / or transmission durations. In the 3GPP NR system, the main services and functions of the RLC sublayer depend on the transmission mode and include: transfer of upper layer PDUs; sequence numbering independent of the one in PDCP (UM and AM); error correction through ARQ (AM only); segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUs; reassembly of SDU (AM and UM); duplicate detection (AM only); RLC SDU discard (AM and UM); RLC re-establishment; protocol error detection (AM only).

[0088] In the 3GPP NR system, the main services and functions of the PDCP sublayer for the user plane include: sequence numbering; header compression and decompression using robust header compression (ROHC); transfer of user data; reordering and duplicate detection; in-order delivery; PDCP PDU routing (in case of split bearers); retransmission of PDCP SDUs; ciphering, deciphering and integrity protection; PDCP SDU discard; PDCP re-establishment and data recovery for RLC AM; PDCP status reporting for RLC AM; duplication of PDCP PDUs and duplicate discard indication to lower layers. The main services and functions of the PDCP sublayer for the control plane include: sequence numbering; ciphering, deciphering and integrity protection; transfer of control plane data; reordering and duplicate detection; in-order delivery; duplication of PDCP PDUs and duplicate discard indication to lower layers.

[0089] In the 3GPP NR system, the main services and functions of SDAP include: mapping between a QoS flow and a data radio bearer; marking QoS flow ID (QFI) in both DL and UL packets. A single protocol entity of SDAP is configured for each individual PDU session.

[0090] In the 3GPP NR system, the main services and functions of the RRC sublayer include: broadcast of system information related to AS and NAS; paging initiated by 5GC or NG-RAN; establishment, maintenance and release of an RRC connection between the UE and NG-RAN; security functions including key management; establishment, configuration, maintenance and release of signaling radio bearers (SRBs) and data radio bearers (DRBs); mobility functions (including: handover and context transfer, UE cell selection and reselection and control of cell selection and reselection, inter-RAT mobility); QoS management functions; UE measurement reporting and control of the reporting; detection of and recovery from radio link failure; NAS message transfer to / from NAS from / to UE.

[0091] FIG. 6 shows a frame structure in a 3GPP based wireless communication system to which implementations of the present disclosure is applied.

[0092] The frame structure shown in FIG. 6 is purely exemplary and the number of subframes, the number of slots, and / or the number of symbols in a frame may be variously changed. In the 3GPP based wireless communication system, OFDM numerologies (e.g., subcarrier spacing (SCS), transmission time interval (TTI) duration) may be differently configured between a plurality of cells aggregated for one UE. For example, if a UE is configured with different SCSs for cells aggregated for the cell, an (absolute time) duration of a time resource (e.g., a subframe, a slot, or a TTI) including the same number of symbols may be different among the aggregated cells. Herein, symbols may include OFDM symbols (or CP-OFDM symbols), SC-FDMA symbols (or discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbols).

[0093] Referring to FIG. 6, downlink and uplink transmissions are organized into frames. Each frame has Tf= 10ms duration. Each frame is divided into two half-frames, where each of the half-frames has 5ms duration. Each half-frame consists of 5 subframes, where the duration Tsfper subframe is 1ms. Each subframe is divided into slots and the number of slots in a subframe depends on a subcarrier spacing. Each slot includes 14 or 12 OFDM symbols based on a cyclic prefix (CP). In a normal CP, each slot includes 14 OFDM symbols and, in an extended CP, each slot includes 12 OFDM symbols. The numerology is based on exponentially scalable subcarrier spacing βf = 2u*15 kHz.

[0094] Table 3 shows the number of OFDM symbols per slot Nslotsymb, the number of slots per frameNframe,uslot, and the number of slots per subframe Nsubframe,uslotfor the normal CP, according to the subcarrier spacing βf = 2u*15 kHz.

[0095] uNslotsymbNframe,uslotNsubframe,uslot01410111420221440431480841416016

[0096] Table 4 shows the number of OFDM symbols per slot Nslotsymb, the number of slots per frameNframe,uslot, and the number of slots per subframe Nsubframe,uslotfor the extended CP, according to the subcarrier spacing βf = 2u*15 kHz.

[0097] uNslotsymbNframe,uslotNsubframe,uslot212404

[0098] A slot includes plural symbols (e.g., 14 or 12 symbols) in the time domain. For each numerology (e.g., subcarrier spacing) and carrier, a resource grid ofNsize,ugrid,x*NRBscsubcarriers andNsubframe,usymbOFDM symbols is defined, starting at common resource block (CRB)Nstart,ugridindicated by higher-layer signaling (e.g., RRC signaling), whereNsize,ugrid,xis the number of resource blocks (RBs) in the resource grid and the subscript x is DL for downlink and UL for uplink.NRBscis the number of subcarriers per RB. In the 3GPP based wireless communication system,NRBscis 12 generally. There is one resource grid for a given antenna portp, subcarrier spacing configurationu, and transmission direction (DL or UL). The carrier bandwidthNsize,ugridfor subcarrier spacing configurationuis given by the higher-layer parameter (e.g., RRC parameter). Each element in the resource grid for the antenna portpand the subcarrier spacing configurationuis referred to as a resource element (RE) and one complex symbol may be mapped to each RE. Each RE in the resource grid is uniquely identified by an indexkin the frequency domain and an indexlrepresenting a symbol location relative to a reference point in the time domain. In the 3GPP based wireless communication system, an RB is defined by 12 consecutive subcarriers in the frequency domain. As shown in FIG. 6, as SCS doubles, the slot length and symbol length are halved. For example, when SCS is 15kHz, the slot length is 1ms, which is the same as the subframe length. When SCS is 30kHz, the slot length is 0.5ms (=500us), and the symbol length is half of that when the SCS is 15kHz. When SCS is 60kHz, the slot length is 0.25ms (=250us), and the symbol length is half of that when the SCS is 30kHz. When SCS is 120kHz, the slot length is 0.125ms (=125us), and the symbol length is half of that when the SCS is 60kHz. When SCS is 240kHz, the slot length is 0.0625ms (=62.5us), and the symbol length is half of that when the SCS is 120kHz.

[0099] In the 3GPP NR system, RBs are classified into CRBs and physical resource blocks (PRBs). CRBs are numbered from 0 and upwards in the frequency domain for subcarrier spacing configurationu. The center of subcarrier 0 of CRB 0 for subcarrier spacing configurationucoincides with 'point A' which serves as a common reference point for resource block grids. In the 3GPP NR system, PRBs are defined within a bandwidth part (BWP) and numbered from 0 toNsizeBWP,i-1, where i is the number of the bandwidth part. The relation between the physical resource block nPRBin the bandwidth part i and the common resource block nCRBis as follows: nPRB= nCRB+NsizeBWP,i, whereNsizeBWP,iis the common resource block where bandwidth part starts relative to CRB 0. The BWP includes a plurality of consecutive RBs. A carrier may include a maximum of N (e.g., 5) BWPs. A UE may be configured with one or more BWPs on a given component carrier. Only one BWP among BWPs configured to the UE can active at a time. The active BWP defines the UE's operating bandwidth within the cell's operating bandwidth.

[0100] In the present disclosure, the term "cell" may refer to a geographic area to which one or more nodes provide a communication system, or refer to radio resources. A "cell" as a geographic area may be understood as coverage within which a node can provide service using a carrier and a "cell" as radio resources (e.g., time-frequency resources) is associated with bandwidth which is a frequency range configured by the carrier. The "cell" associated with the radio resources is defined by a combination of downlink resources and uplink resources, for example, a combination of a DL component carrier (CC) and a UL CC. The cell may be configured by downlink resources only, or may be configured by downlink resources and uplink resources. Since DL coverage, which is a range within which the node is capable of transmitting a valid signal, and UL coverage, which is a range within which the node is capable of receiving the valid signal from the UE, depends upon a carrier carrying the signal, the coverage of the node may be associated with coverage of the "cell" of radio resources used by the node. Accordingly, the term "cell" may be used to represent service coverage of the node sometimes, radio resources at other times, or a range that signals using the radio resources can reach with valid strength at other times.

[0101] In CA, two or more CCs are aggregated. A UE may simultaneously receive or transmit on one or multiple CCs depending on its capabilities. CA is supported for both contiguous and non-contiguous CCs. When CA is configured, the UE only has one RRC connection with the network. At RRC connection establishment / re-establishment / handover, one serving cell provides the NAS mobility information, and at RRC connection re-establishment / handover, one serving cell provides the security input. This cell is referred to as the primary cell (PCell). The PCell is a cell, operating on the primary frequency, in which the UE either performs the initial connection establishment procedure or initiates the connection re-establishment procedure. Depending on UE capabilities, secondary cells (SCells) can be configured to form together with the PCell a set of serving cells. An SCell is a cell providing additional radio resources on top of special cell (SpCell). The configured set of serving cells for a UE therefore always consists of one PCell and one or more SCells. For dual connectivity (DC) operation, the term SpCell refers to the PCell of the master cell group (MCG) or the primary SCell (PSCell) of the secondary cell group (SCG). An SpCell supports PUCCH transmission and contention-based random access, and is always activated. The MCG is a group of serving cells associated with a master node, comprised of the SpCell (PCell) and optionally one or more SCells. The SCG is the subset of serving cells associated with a secondary node, comprised of the PSCell and zero or more SCells, for a UE configured with DC. For a UE in RRC_CONNECTED not configured with CA / DC, there is only one serving cell comprised of the PCell. For a UE in RRC_CONNECTED configured with CA / DC, the term "serving cells" is used to denote the set of cells comprised of the SpCell(s) and all SCells. In DC, two MAC entities are configured in a UE: one for the MCG and one for the SCG.

[0102] FIG. 7 shows a data flow example in the 3GPP NR system to which implementations of the present disclosure is applied.

[0103] Referring to FIG. 7, "RB" denotes a radio bearer, and "H" denotes a header. Radio bearers are categorized into two groups: DRBs for user plane data and SRBs for control plane data. The MAC PDU is transmitted / received using radio resources through the PHY layer to / from an external device. The MAC PDU arrives to the PHY layer in the form of a transport block.

[0104] In the PHY layer, the uplink transport channels UL-SCH and random access channel (RACH) are mapped to their physical channels physical uplink shared channel (PUSCH) and physical random access channel (PRACH), respectively, and the downlink transport channels DL-SCH, BCH and PCH are mapped to physical downlink shared channel (PDSCH), physical broadcast channel (PBCH) and PDSCH, respectively. In the PHY layer, uplink control information (UCI) is mapped to physical uplink control channel (PUCCH), and downlink control information (DCI) is mapped to physical downlink control channel (PDCCH). A MAC PDU related to UL-SCH is transmitted by a UE via a PUSCH based on an UL grant, and a MAC PDU related to DL-SCH is transmitted by a BS via a PDSCH based on a DL assignment.

[0105] FIG. 8 shows an example of a dual connectivity (DC) architecture to which technical features of the present disclosure can be applied.

[0106] Referring to FIG. 8, MN 811, SN 821, and a UE 830 communicating with both the MN 811 and the SN 821 are illustrated. As illustrated in FIG. 8, DC refers to a scheme in which a UE (e.g., UE 830) utilizes radio resources provided by at least two RAN nodes comprising a MN (e.g., MN 811) and one or more SNs (e.g., SN 821). In other words, DC refers to a scheme in which a UE is connected to both the MN and the one or more SNs, and communicates with both the MN and the one or more SNs. Since the MN and the SN may be in different sites, a backhaul between the MN and the SN may be construed as non-ideal backhaul (e.g., relatively large delay between nodes).

[0107] MN (e.g., MN 811) refers to a main RAN node providing services to a UE in DC situation. SN (e.g., SN 821) refers to an additional RAN node providing services to the UE with the MN in the DC situation. If one RAN node provides services to a UE, the RAN node may be a MN. SN can exist if MN exists.

[0108] For example, the MN may be associated with macro cell whose coverage is relatively larger than that of a small cell. However, the MN does not have to be associated with macro cell - that is, the MN may be associated with a small cell. Throughout the disclosure, a RAN node that is associated with a macro cell may be referred to as 'macro cell node'. MN may comprise macro cell node.

[0109] For example, the SN may be associated with small cell (e.g., micro cell, pico cell, femto cell) whose coverage is relatively smaller than that of a macro cell. However, the SN does not have to be associated with small cell - that is, the SN may be associated with a macro cell. Throughout the disclosure, a RAN node that is associated with a small cell may be referred to as 'small cell node'. SN may comprise small cell node.

[0110] The MN may be associated with a master cell group (MCG). MCG may refer to a group of serving cells associated with the MN, and may comprise a primary cell (PCell) and optionally one or more secondary cells (SCells). User plane data and / or control plane data may be transported from a core network to the MN through a MCG bearer. MCG bearer refers to a bearer whose radio protocols are located in the MN to use MN resources. As shown in FIG. 8, the radio protocols of the MCG bearer may comprise PDCP, RLC, MAC and / or PHY.

[0111] The SN may be associated with a secondary cell group (SCG). SCG may refer to a group of serving cells associated with the SN, and may comprise a primary secondary cell (PSCell) and optionally one or more SCells. User plane data may be transported from a core network to the SN through a SCG bearer. SCG bearer refers to a bearer whose radio protocols are located in the SN to use SN resources. As shown in FIG. 8, the radio protocols of the SCG bearer may comprise PDCP, RLC, MAC and PHY.

[0112] User plane data and / or control plane data may be transported from a core network to the MN and split up / duplicated in the MN, and at least part of the split / duplicated data may be forwarded to the SN through a split bearer. Split bearer refers to a bearer whose radio protocols are located in both the MN and the SN to use both MN resources and SN resources. As shown in FIG. 8, the radio protocols of the split bearer located in the MN may comprise PDCP, RLC, MAC and PHY. The radio protocols of the split bearer located in the SN may comprise RLC, MAC and PHY.

[0113] According to various embodiments, PDCP anchor / PDCP anchor point / PDCP anchor node refers to a RAN node comprising a PDCP entity which splits up and / or duplicates data and forwards at least part of the split / duplicated data over X2 / Xn interface to another RAN node. In the example of FIG. 8, PDCP anchor node may be MN.

[0114] According to various embodiments, the MN for the UE may be changed. This may be referred to as handover, or a MN handover.

[0115] According to various embodiments, a SN may newly start providing radio resources to the UE, establishing a connection with the UE, and / or communicating with the UE (i.e., SN for the UE may be newly added). This may be referred to as a SN addition.

[0116] According to various embodiments, a SN for the UE may be changed while the MN for the UE is maintained. This may be referred to as a SN change.

[0117] According to various embodiments, DC may comprise E-UTRAN NR - DC (EN-DC), and / or multi-radio access technology (RAT) - DC (MR-DC). EN-DC refers to a DC situation in which a UE utilizes radio resources provided by E-UTRAN node and NR RAN node. MR-DC refers to a DC situation in which a UE utilizes radio resources provided by RAN nodes with different RATs.

[0118] Hereinafter, contents regarding mobility are described.

[0119] The mobility may comprise PCell change, PSCell change (or, secondary node (SN) change), and / or PSCell addition (or, SN addition).

[0120] In the present disclosure, the term "handover (HO)" may mean PCell change, or may be a broad concept that includes not only PCell change but also PSCell change / addition.

[0121] In the present disclosure, the terms "handover" and "mobility" can be used interchangeably.

[0122] In the present disclosure, the description regarding handover can also be applied to other mobility procedures (e.g., PSCell change / addition).

[0123] There may be at least two types of mobility: network-controlled mobility (or, legacy mobility) and UE-based mobility (or, conditional mobility).

[0124] The network-controlled mobility (or, legacy mobility) is a mobility where the network determines a target cell for mobility, and configures UE with the target cell. The network may transmit, to the UE, anRRCReconfigurationmessage comprising a configuration for the target cell. The UE may execute a mobility to the target cell and / or apply the configuration for the target cell, upon receiving the cell configuration for the target cell.

[0125] The UE-based mobility (or, conditional mobility) is a mobility where the network configures the UE with a plurality of candidate cells, and the UE determines a target cell which satisfies a mobility execution condition among the plurality of candidate cells. The conditional mobility may comprise at least one of a conditional PCell change / conditional handover (CHO) or a conditional PSCell mobility. The conditional PSCell mobility may comprise conditional PSCell addition / change (CPAC), including conditional PSCell addition (CPA) and / or conditional PSCell change (CPC). The network may transmit, to the UE, anRRCReconfigurationmessage comprisingConditionalReconfigurationinformation element (IE), which comprises a list of conditional reconfigurations for the plurality of candidate cells. A conditional reconfiguration for a candidate cell may comprise an identifier of the conditional reconfiguration, a mobility execution condition for the candidate cell, and a configuration for the candidate cell. The UE may evaluate the mobility execution conditions for the plurality of candidate cells, and when a mobility execution condition for a candidate cell is satisfied, the UE may consider the candidate cell as a target cell, and execute a mobility to the target cell and / or apply the configuration for the target cell.

[0126] According to various embodiments, the mobility execution condition may be satisfied / met when an entry condition (or, entering condition) for the mobility execution condition is satisfied / met for at least a time-to-trigger (TTT) for the mobility execution condition. The entry condition / entering condition may mean that the mobility execution condition is initially met. Once the entry condition is met, the mobility execution condition will be considered to be met if the entry condition is met for time duration TTT continuously.

[0127] FIG. 9 shows an example of a conditional mobility procedure according to an embodiment of the present disclosure.

[0128] In FIG. 9:

[0129] - the serving BS may be related to a PCell, which may be a source PCell for CHO;

[0130] - the serving BS may be an MN associated with an SN in DC, where the SN may be related to a source PSCell for CPC; and

[0131] - the target cell may be a target PCell for CHO, or a target PSCell for CPA / CPC.

[0132] Referring to FIG. 9, in step S901, UE may receive, from the serving BS, anRRCReconfiguraitonmessage comprising a conditional reconfiguration information element (IE) (i.e.,CondidtionalReconfiguration). The conditional reconfiguration IE may comprise a list of conditional reconfigurations for candidate cells including the target cell. Each conditional reconfiguration in the list may be related to the corresponding candidate cell, and comprises i) an identifier of the corresponding conditional reconfiguration (i.e.,condReconfigId), ii) one or more execution conditions for the corresponding candidate cell (i.e.,condExecutionCond), and / or iii) RRC reconfiguration for the corresponding candidate cell (i.e.,condRRCReconfig) including a cell configuration for the corresponding candidate cell. The one or more execution conditions may comprise CHO execution condition(s), CPA execution condition(s), and / or CPC execution condition(s).

[0133] In step S903, the UE may start evaluating the one or more execution conditions for the candidate cells.

[0134] In step S905, if the target cell satisfies the corresponding execution condition(s), the UE may execute the conditional mobility towards the target cell and / or apply the RRC reconfiguration for the target cell including a cell configuration for the target cell. When / upon executing the conditional mobility and / or applying the RRC reconfiguration (e.g.,RRCReconfigurationincludingReconfigurationWithSync) for the target cell, the UE may start a timer (e.g., T304 timer). The timer value of the T304 timer (i.e., T304 timer value) for the target cell may be included in theReconfigurationWithSyncinRRCReconfigurationfor the target cell.

[0135] While the timer is running, the UE may perform DL synchronization and / or UL synchronization (e.g., random access) towards the target cell. The UE may skip the random access towards the target cell if timing advance (TA) information for the target cell is available.

[0136] In step S907, the UE, serving BS and / or BS related to the target cell may perform actions related to conditional mobility completion. For example, upon successful completion of the random access on the corresponding target cell, the UE may stop the timer (e.g., T304 timer).

[0137] Hereinafter, simultaneous evaluation for CHO and CPAC is described.

[0138] In a wireless communication system, CHO including target MCG and target SCG may be supported, and CHO configuration referring to or including CPC / CPA configuration (intended to be applicable together) may be supported. When triggering CHO, UE may perform CPC / CPA configuration to start CPC / CPA evaluation. CHO evaluation and CPC / CPA evaluation may be concurrent or sequential.

[0139] As stated above, CHO with SCG configurations is already supported. However, the CHO with SCG configuration is still triggered under the normal CHO triggering conditions (e.g., CondEventA3, CondEventA5) that are based only on the target / source PCell's quality. The drawback of this is that the target SCG (PSCell) is added blindly without taking its quality (or / and the source PSCell) into consideration. Doing so may result in adding an SCG in bad radio conditions, and subsequent SCG failure, SCG failure recovery and reconfigurations.

[0140] Thus, a more optimal approach is to also consider the conditions of the target / source PSCell. That is:

[0141] - A UE can be configured with a CHO and associated SCG and configured to consider triggering conditions on the source / target PCell and source / target PSCell; and / or

[0142] - A UE will monitor both triggering conditions and execute the CHO with the associated SCG only if both triggering conditions are fulfilled.

[0143] In some scenarios, it could be possible that there can be several candidate PSCells for a certain PCell. This can be realized via implementation, where a CHO with associated SCG is configured for each possible PSCell. However, this is inefficient signalling, as the MCG configuration is repeated in each configuration. A more optimal solution is to have a CHO that can be configured / associated with multiple SCGs, each with its own triggering conditions. For example, a CHO can be associated with multiple SCGs, each having different triggering conditions.

[0144] For example, a UE may be configured with a CHO configuration that has two associated SCGs, SCG1 and SCG2. If the triggering conditions for the PCell and PSCell1 get fulfilled, the UE will execute the CHO with SCG1. If the triggering conditions for the PCell and PSCell2 get fulfilled, the UE will execute the CHO with SCG2. Releasing all conditional reconfigurations upon the execution of another conditional reconfiguration will result in unnecessary reconfigurations. Thus, it is proposed that, when a UE executes a CHO with multiple SCGs associated with it, it may be configured to keep the other SCG configurations associated with the SCG and keep monitoring their triggering conditions.

[0145] With regard to the RRC signalling structure design, there are two main possibilities:

[0146] a) A CHO containing the MCG configuration (and triggering conditions) and the associated SCG configuration(s) (and the SCG triggering conditions)

[0147] b) A CHO containing only the MCG configuration (and PCell change triggering condition), separate configuration for each SCG (i.e., a CPC with SCG configuration and PSCell change triggering condition), and a configuration associating the CHO with the SCG configuration(s) (e.g., in a way like a measurement ID associates a measurement object and a measurement reporting configuration).

[0148] That is, at least one of the following structures for defining CHO with associated SCG may be considered:

[0149] a) One CHO configuration containing all the MCG configuration, SCG configuration(s), and triggering conditions for the PCell change and PSCell change; and / or

[0150] b) Separate CHO and CPAC configuration(s), and a configuration associating the CHO and CPAC configuration(s).

[0151] In the present disclosure, CHO+CPC / CPA refers to a mobility procedure in which CHO and CPC / CPA are performed together when both of the CHO execution condition and the CPC / CPA execution condition are satisfied. In other words, in CHO+CPC / CPA, CHO is performed only when both of the CHO execution condition and the CPC / CPA execution condition are satisfied, and CPC / CPA is performed only when both of the CHO execution condition and the CPC / CPA execution condition are satisfied. If at least one of the CHO execution condition or the CPC / CPA execution condition is not satisfied, neither CHO nor CPC / CPA is performed.

[0152] For the CHO+CPC / CPA case, when both CHO and CPC / CPA execution conditions are met, both CHO and CPC / CPA cell change is executed. The UE may wait until both CHO and CPC execution conditions are met. Furthermore, it is assumed that if needed the network can provide a complementary CHO-only configuration, to avoid failures in deployments where failure would otherwise be likely to happen. Alternatively, when CHO execution condition is met but CPC execution condition is not met, CHO execution is triggered (and somehow source SCG can be released). If allowed in the new configuration, the UE may continue evaluation of CPC / CPA execution conditions.

[0153] According to various embodiments, the UE may receive a list of conditional reconfigurations (i.e.,CondReconfigToAddModListIE) from a network. The IECondReconfigToAddModListconcerns a list of conditional reconfigurations to add or modify, with for each entry thecondReconfigIdand the associated fields, as shown in table 5 below:

[0154] 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 {condReconfigId-r18 CondReconfigId-r16,condExecutionCond-r18 SEQUENCE (SIZE (1..2)) OF MeasId OPTIONAL, -- Need McondExecutionCondSCG-r18 OCTET STRING (CONTAINING CondReconfigExecCondSCG-r17) OPTIONAL, -- Need M...}CondExecutionCondToReleaseList-r18 ::= SEQUENCE (SIZE (1.. maxNrofCondCells-r16)) OF CondReconfigId-r16

[0155] In table 5:-condExecutionCond(e.g., execution condition of second type for target PSCell) is the execution condition that needs to be fulfilled in order to trigger the execution of a conditional reconfiguration for CHO, CPA, intra-SN CPC without MN involvement, MN initiated inter-SN CPC, or SN initiated intra-SN subsequent CPAC without MN involvement. When configuring 2 triggering events (Meas Ids) for a candidate cell, the network ensures that both refer to the samemeasObject.For CHO, if the network configurescondEventD1orcondEventT1for a candidate cell, the network configures a second triggering eventcondEventA3, condEventA4orcondEventA5for the same candidate cell. The network does not configure bothcondEventD1andcondEventT1for the same candidate cell. For CHO in terrestrial networks, the network does not indicate aMeasIdassociated withcondEventA4. For CPA and for MN-initiated inter-SN CPC, the network only indicatesMeasId(s) associated withcondEventA4. For intra-SN CPC and intra-SN subsequent CPAC, the network only indicatesMeasId(s) associated withcondEventA3orcondEventA5;

[0156] -condExecutionCondPSCell(i.e., execution condition of first type for target PSCell) is the execution condition that needs to be fulfilled for the associated PSCell in order to trigger the execution of a conditional reconfiguration for CHO with candidate SCG(s). The Meas Ids refer to themeasConfigassociated with the MCG. When configuring 2 triggering events (Meas Ids) for a candidate cell, network ensures that both refer to the samemeasObject. The network only indicatesMeasId(s)associated with condEventA4;

[0157] -condExecutionCondSCGcontains execution condition that needs to be fulfilled in order to trigger the execution of a conditional reconfiguration for SN initiated inter-SN CPC, SN initiated inter-SN subsequent CPAC, SN initiated intra-SN subsequent CPAC with MN involvement, or MN initiated inter-SN subsequent CPAC. The Meas Ids refer to themeasConfigassociated with the SCG. When configuring 2 triggering events (Meas Ids) for a candidate cell, network ensures that both refer to the samemeasObject. For eachcondReconfigId, the network always configures eithercondExecutionCondorcondExecutionCondSCG(not both). The network only indicatesMeasId(s) associated withcondEventA3orcondEventA5;

[0158] -condRRCReconfigis theRRCReconfigurationmessage comprising a cell configuration for the corresponding target cell to be applied when the condition(s) are fulfilled. TheRRCReconfigurationmessage contained incondRRCReconfigcannot contain the fieldconditionalReconfigurationor the fielddaps-Config;

[0159] -scpac-ConfigCompleteindicates whether the configuration contained incondRRCReconfigfor subsequent CPAC is a complete configuration; and

[0160] -subsequentCondReconfigcontains the execution conditions (e.g., execution condition of second type for target PSCell) that need to be fulfilled in order to trigger the execution of a subsequent CPAC. If the field is configured, the configuration of candidate PSCells for subsequent CPAC is supported. The subsequent execution condition is used for conditional reconfiguration evaluation for other candidate cells when theRRCReconfigurationmessage contained incondRRCReconfighas been applied.

[0161] After receiving the list of conditional reconfigurations, the UE may perform conditional reconfiguration evaluation. The UE shall:

[0162] 1> for eachcondReconfigIdwithin theVarConditionalReconfig:

[0163] 2> if theRRCReconfigurationwithincondRRCReconfigincludes themasterCellGroupincluding thereconfigurationWithSync:

[0164] 3> if the associatedcondExecutionCondPSCellis configured:

[0165] 4> consider the cell which has a physical cell identity matching the value indicated in theServingCellConfigCommonincluded in thereconfigurationWithSyncwithin themasterCellGroupin the receivedcondRRCReconfigto be applicable cell; and

[0166] 4> consider the cell which has a physical cell identity matching the value indicated in theServingCellConfigCommonincluded in thereconfigurationWithSyncwithin thesecondaryCellGroupwithin thenr-SCGwithin the receivedcondRRCReconfigto be applicable cell;

[0167] 3> else:

[0168] 4> consider the cell which has a physical cell identity matching the value indicated in theServingCellConfigCommonincluded in thereconfigurationWithSyncwithin themasterCellGroupin the receivedcondRRCReconfigto be applicable cell;

[0169] 2> else if theRRCReconfigurationwithincondRRCReconfigincludes thesecondaryCellGroupincluding thereconfigurationWithSync:

[0170] 3> if the cell which has a physical cell identity matching the value indicated in theServingCellConfigCommonincluded in thereconfigurationWithSyncwithin thesecondaryCellGroupwithin the receivedcondRRCReconfigis not the PSCell:

[0171] 4> consider the cell to be applicable cell;

[0172] 2> ifcondExecutionCondSCGis configured:

[0173] 3> in the remainder of the procedure, consider eachmeasIdindicated in thecondExecutionCondSCGas ameasIdin theVarMeasConfigassociated with the SCGmeasConfig;

[0174] 2> if thecondExecutionCondPSCellis configured:

[0175] 3> in the remainder of the procedure, consider eachmeasIdindicated in thecondExecutionCondPSCellas ameasIdin theVarMeasConfigassociated with the MCGmeasConfig;

[0176] 2> ifcondExecutionCondis configured:

[0177] 3> if it is configured via SRB3 or configured withinnr-SCGor withinnr-SecondaryCellGroupConfigvia SRB1:

[0178] 4> in the remainder of the procedure, consider eachmeasIdindicated in thecondExecutionCondas ameasIdin theVarMeasConfigassociated with the SCGmeasConfig;

[0179] 3> else:

[0180] 4> in the remainder of the procedure, consider eachmeasIdindicated in thecondExecutionCondas ameasIdin theVarMeasConfigassociated with the MCGmeasConfig;

[0181] 2> for eachmeasIdincluded in themeasIdListwithinVarMeasConfigindicated in thecondExecutionCond,condExecutionCondSCG,orcondExecutionCondPSCellassociated tocondReconfigId:

[0182] 3> if thecondEventIdis associated withcondEventT1, and if the entry condition applicable for this event associated with thecondReconfigId, i.e. the event corresponding with thecondEventId(s)of the correspondingcondTriggerConfigwithinVarConditionalReconfig, is fulfilled for the applicable cell; or

[0183] 3> if thecondEventIdis associated withcondEventD1, and if the entry conditions applicable for this event associated with thecondReconfigId, i.e. the event corresponding with thecondEventId(s)of the correspondingcondTriggerConfigwithinVarConditionalReconfig, is fulfilled for the applicable cell during the correspondingtimeToTriggerdefined for this event within theVarConditionalReconfig; or

[0184] 3> if thecondEventIdis associated withcondEventA3,condEventA4orcondEventA5, and if the entry condition(s) applicable for this event associated with thecondReconfigId, i.e. the event corresponding with thecondEventId(s)of the correspondingcondTriggerConfigwithinVarConditionalReconfig, is fulfilled for the applicable cells for all measurements after layer 3 filtering taken during the correspondingtimeToTriggerdefined for this event within theVarConditionalReconfig:

[0185] 4> consider the event associated to thatmeasIdto be fulfilled;

[0186] 3> if themeasIdfor this event associated with thecondReconfigIdhas been modified; or

[0187] 3> if thecondEventIdis associated withcondEventT1, and if the leaving condition applicable for this event associated with thecondReconfigId, i.e. the event corresponding with thecondEventId(s)of the correspondingcondTriggerConfigwithinVarConditionalReconfig, is fulfilled for the applicable cell; or

[0188] 3> if thecondEventIdis associated withcondEventD1, and if the leaving condition(s) applicable for this event associated with thecondReconfigId, i.e. the event corresponding with thecondEventId(s)of the correspondingcondTriggerConfigwithinVarConditionalReconfig, is fulfilled for the applicable cell during the correspondingtimeToTriggerdefined for this event within theVarConditionalReconfig; or

[0189] 3> if thecondEventIdis associated withcondEventA3,condEventA4orcondEventA5, and if the leaving condition(s) applicable for this event associated with thecondReconfigId, i.e. the event corresponding with thecondEventId(s)of the correspondingcondTriggerConfigwithinVarConditionalReconfig, is fulfilled for the applicable cells for all measurements after layer 3 filtering taken during the correspondingtimeToTriggerdefined for this event within theVarConditionalReconfig:

[0190] 4> consider the event associated to thatmeasIdto be not fulfilled;

[0191] 2> ifcondExecutionCondPSCellis not configured:

[0192] 3> if event(s) associated to allmeasId(s) withincondTriggerConfigfor the applicable cell are fulfilled:

[0193] 4> consider the applicable cell, associated to thatcondReconfigId, as a triggered cell;

[0194] 4> initiate the conditional reconfiguration execution;

[0195] 2> else:

[0196] 3> if event(s) associated to allmeasId(s), as indicated in thecondExecutionCondandcondExecutionCondPSCell,withincondTriggerConfigfor a target candidate cell within the storedcondRRCReconfigare fulfilled:

[0197] 4> consider the target candidate PCell within the storedcondRRCReconfig, associated to thatcondReconfigId, as a triggered PCell;

[0198] 4> consider the target candidate PSCell within the storedcondRRCReconfig, associated to thatcondReconfigId, as a triggered PSCell;

[0199] 4> initiate the conditional reconfiguration execution.

[0200] Up to 2MeasIdcan be configured for eachcondReconfigId, ifcondExecutionCondPSCellis not configured.The conditional reconfiguration event of the 2MeasIdmay have the same or different event conditions, triggering quantity, time to trigger, and triggering threshold.

[0201] For CHO with candidate SCGs, up to 2MeasIdcan be configured forcondExecutionCondandup to 2MeasIdcan be configured forcondExecutionCondPSCellfor eachcondReconfigId.

[0202] Upon the conditional reconfiguration execution, the UE shall:

[0203] 1> if more than one pair of triggered PCell and associated triggered PSCell exist:

[0204] 2> select one of the triggered PCell(s) and the associated triggered PSCell(s) as the selected cells for conditional reconfiguration execution;

[0205] 1> else if only one pair of triggered PCell and associated triggered PSCell exists:

[0206] 2> consider the triggered PCell and the associated triggered PSCell as the selected cells for conditional reconfiguration execution;

[0207] 1> else if more than one triggered cell exists:

[0208] 2> select one of the triggered cells as the selected cell for conditional reconfiguration execution;

[0209] 1> else:

[0210] 2> consider the triggered cell as the selected cell for conditional reconfiguration execution;

[0211] 1> for the selected cell(s) of conditional reconfiguration execution:

[0212] 2> if thesubsequentCondReconfigis included in the entry inVarConditionalReconfigcontaining theRRCReconfigurationmessage for the selected cell:

[0213] 3> perform the subsequent CPAC execution;

[0214] 2> else:

[0215] 3> apply the storedcondRRCReconfigof the selected cell and applyRRCReconfigurationin thecondRRCReconfig.

[0216] If multiple NR cells are triggered in conditional reconfiguration execution, the UE may select one of them. For example, the UE may consider beams and / or beam quality to select one of the triggered cells for execution.

[0217] Upon the conditional reconfiguration execution for subsequent CPAC, the UE shall:

[0218] 1> if the selected subsequent CPAC candidate configuration is stored in MCGVarConditionalReconfig:

[0219] 2> release / clear all current dedicated radio configuration except for the following:

[0220] - the MCG C-RNTI;

[0221] - the AS security configurations associated with the master key and the secondary key;

[0222] - for each SRB / DRB in current UE configuration:

[0223] - keep the associated RLC, PDCP and SDAP entities, their state variables, buffers and timers;

[0224] - release all fields related to the SRB / DRB configuration except forsrb-Identityanddrb-Identity;

[0225] - the UE variablesVarConditionalReconfigandVarServingSecurityCellSetID.

[0226] 2> release / clear all current common radio configuration;

[0227] 1> else:

[0228] 2> release / clear all current dedicated radio configuration associated with the SCG except for the following:

[0229] - the AS security configurations associated with the secondary key;

[0230] - for each SRB / DRB in current UE configuration which is using the secondary key:

[0231] - keep the associated RLC, PDCP and SDAP entities, their state variables, buffers and timers;

[0232] - release all fields related to the SRB / DRB configuration except forsrb-Identityanddrb-Identity;

[0233] - the UE variablesVarConditionalReconfig.

[0234] 2> release / clear all current common radio configuration associated with the SCG;

[0235] 1> use the default values for timers T310, T311 and constants N310, N311 for the cell group for which the subsequent CPAC cell switch procedure is triggered;

[0236] 1> if thesecurityCellSetIdis included in the entry inVarConditionalReconfigcontaining theRRCReconfigurationmessage:

[0237] 2> ifservingSecurityCellSetIdis not included withinVarServingSecurityCellSetID; or

[0238] 2> if the value of thesecurityCellSetIdis not equal to the value ofservingSecurityCellSetIdwithinVarServingSecurityCellSetID:

[0239] 3> consider the firstsk-Countervalue in thesk-CounterListassociated with thesecurityCellSetIdwithin theVarConditionalReconfigas the selectedsk-Countervalue, and perform security key update procedure;

[0240] 3> remove the selectedsk-Countervalue from thesk-CounterListassociated with thesecurityCellSetIdwithin theVarConditionalReconfig;

[0241] 3> if the currentVarServingSecurityCellSetIDincludesservingSecurityCellSetId:

[0242] 4> replace the value ofservingSecurityCellSetIdwithinVarServingSecurityCellSetIDwith the value ofsecurityCellSetIdassociated with the selected cell;

[0243] 3> else:

[0244] 4> store theservingSecurityCellSetIdwithinVarServingSecurityCellSetIDwith the value ofsecurityCellSetIdassociated with the selected cell;

[0245] 1> if the selected subsequent CPAC candidate configuration is stored in the SCGVarConditionalReconfig:

[0246] 2> for eachdrb-Identityvalue included inRadioBearerConfigassociated with the secondary key (S-KgNB) as indicated bykeyToUsethat is part of the current UE configuration:

[0247] 3> trigger the PDCP entity of the AM DRB to perform PDCP data recovery;

[0248] 3> re-establish the corresponding RLC entity;

[0249] 1> else:

[0250] 2> for eachdrb-Identityvalue included inRadioBearerConfigthat is part of the current UE configuration:

[0251] 3> if a differentkeyToUsevalue is configured;or

[0252] 3> if a newsk-Countervalue has been selected due to the conditional reconfiguration execution for subsequent CPAC:

[0253] 4> trigger the PDCP entity of the bearer to perform PDCP reestablishment;

[0254] 3> else:

[0255] 4> trigger the PDCP entity of the AM DRB to perform PDCP data recovery;

[0256] 4> re-establish the corresponding RLC entity;

[0257] 1> ifscpac-ConfigCompleteis not included within theVarConditionalReconfigfor the selected cell:

[0258] 2> if the subsequent CPAC candidate cell configuration is stored in MCGVarConditionalReconfig:

[0259] 3> considerscpac-ReferenceConfigurationin MCGVarConditionalReconfigto be the current UE configuration;

[0260] 2> else:

[0261] 3> considerscpac-ReferenceConfigurationin SCGVarConditionalReconfigto be the current SCG configuration;

[0262] When the UE considers the reference configuration to be the current UE configuration, the UE should store fields and configurations that are part of the reference configuration but should not execute any actions or procedures triggered by the reception of anRRCReconfigurationmessage.

[0263] 1> apply the storedcondRRCReconfigof the selected cell(s) and apply theRRCReconfigurationin thecondRRCReconfig.

[0264] 1> release the radio bearer(s) and the associated logical channel(s) that are part of the current UE configuration but not part of the subsequent CPAC candidate configuration for the selected cell, or the subsequent CPAC reference configuration (in case the subsequent CPAC candidate configuration does not includescpac-ConfigComplete).

[0265] Whenscpac-ConfigCompleteis not included for the selected cell, before a subsequent CPAC execution, a UE implementation may generate and store an RRC reconfiguration message by applying the received subsequent CPAC candidate configuration on top of the subsequent CPAC reference configuration, and the stored RRC reconfiguration message is applied for subsequent CPAC execution.

[0266] Meanwhile, UE may be configured with CHO and associated CPC / CPA which is supposed to be used after CHO execution. That is, the network may configure CHO configuration and CPC / CPA configuration which is referred to CHO or is included in the CHO configuration (i.e., CHO+CPC / CPA configuration). Through this feature, the UE can more precisely select a suitable target cell for PSCell than in a previous case where the UE is configured with CHO and associated SCG configuration together. This is because the associated SCG configuration which should be applied after CHO is completed may be invalid due to a long time for CHO evaluation. For the case that the UE is configured with CHO and the associated CPC / CPA together, the UE may evaluate CHO condition and the associated CPC / CPA condition simultaneously to execute the CPC / CPA quickly.

[0267] If UE declares a mobility failure or radio link failure while utilizing the CHO+CPC / CPA configuration provided by the network, the network cannot determine why the CHO+CPC / CPA configuration was not applied by the UE before the declaration of the failure. In particular, the network cannot know the status of the execution conditions provided for CPC / CPA, so even if the network provides similar CHO+CPC / CPA configuration to other UEs in similar situations, those UEs may not be able to apply the CHO+CPC / CPA configuration and may experience the same mobility failure or radio link failure. Two main reasons why similar failure can happen are below:

[0268] - The network cannot determine which execution condition among all the execution conditions for CHO and CPA / CPC provided for CHO+CPA / CPC was not satisfied, causing the UE to fail to the mobility; and / or

[0269] - The network cannot determine the difference between the PSCell quality of the SCG provided for CHO only (i.e., the CHO configuration may optionally include the SCG configuration but may not include the CPC / CPA configuration) and the PSCell quality of target PSCell for CPC / CPA in the CHO+CPC / CPA.

[0270] Further, even if the UE successfully performs PCell mobility (e.g., CHO), the UE may not utilize the CHO+CPC / CPA configuration and may trigger other type of mobility (i.e., CHO without SCG or CHO+SCG configuration). In this case, even if the UE was provided with CHO+CPC / CPA configuration to prevent SCG failure, SCG failure can still occur frequently during PCell mobility because the UE did not use the CHO+CPC / CPA configuration. To prevent SCG failure in similar situations for other UEs who were also provided with CHO+CPC / CPA configuration, the network needs additional information such as logging information from the UE when PCell mobility is successful.

[0271] Moreover, if there is no execution condition to compare the source PSCell signal quality for CPA / CPC configuration configured with CHO, the UE may need to perform additional PSCell change because the signal quality of the source PSCell can be still better than the target PSCell. In this case, the network needs to be provided with the signal quality of the source PSCell along with the logging information to prevent unnecessary mobility caused by the UE searching for a better PSCell.

[0272] Therefore, the present disclosure provides various embodiments for logging and reporting mobility information after the mobility procedure is ended.

[0273] In the present disclosure:

[0274] - The SCG configuration associated with a CHO configuration (i.e., associated SCSG configuration) means a configuration for SCG that can be applied together with the CHO configuration for a target PCell when applying the CHO configuration for the target PCell after a CHO execution condition for the target PCell is met.

[0275] - The CPA / CPC configuration associated with a CHO configuration (i.e., associated CPA / CPC configuration) means a conditional (re)configuration for SCG that can be applied together with a PCell mobility based on the CHO configuration when both the CHO execution condition and the CPA / CPC execution condition are met. For example, when at least one of the CHO execution condition or the CPA / CPC execution condition is not satisfied, neither the CHO configuration nor the associated CPA / CPC configuration is applied.

[0276] - An evaluation status of an execution condition may indicate: whether an entering condition of the execution condition is satisfied; whether the execution condition is satisfied; whether a leaving condition of the execution condition is satisfied; and / or how long the entering condition is satisfied among TTT for the execution condition, or how short a duration is left after a duration the entering condition is satisfied among the TTT.

[0277] FIG. 10 shows an example of a method performed by a communication device according to an embodiment of the present disclosure. The method may also be performed by UE and / or wireless device.

[0278] Referring to FIG. 10, in step S1001, the communication device may receive a conditional reconfiguration comprising execution conditions for mobility including i) a first execution condition for a PCell mobility to a target PCell, and ii) a second execution condition for a PSCell mobility to a target PSCell associated with the target PCell.

[0279] In step S1003, the communication device may evaluate the execution conditions including the first execution condition for the target PCell and the second execution condition for the associated target PSCell.

[0280] In step S1005, the communication device may perform a mobility procedure based on one or more execution conditions among the execution conditions being satisfied.

[0281] In step S1007, after the mobility procedure ends, the communication device may transmit mobility information comprising: first information for an execution condition that is satisfied first among the first execution condition and the second execution condition; and second information for a time duration that has elapsed since the execution condition was satisfied.

[0282] According to various embodiments, based on the target PSCell being associated with the target PCell: a mobility towards the target PCell and a mobility towards the target PSCell are performed together when both of the first execution condition for the target PCell and the second execution condition for the target PSCell are satisfied; and neither the mobility towards the target PCell nor the mobility towards the target PSCell is performed when at least one of the first execution condition for the target PCell or the second execution condition for the target PSCell is satisfied.

[0283] According to various embodiments, the mobility procedure may end in failure. The mobility information may comprise mobility failure information (e.g., handover failure information) comprising the first information and the second information.

[0284] According to various embodiments, the communication device may initiate a radio resource control (RRC) re-establishment procedure based on a failure of the mobility procedure. The communication device may log the mobility failure information based on initiating the RRC re-establishment procedure.

[0285] According to various embodiments, the logged mobility failure information may further comprise at least one of: a cell identity of the target PCell; a measurement result of the target PCell; a cell identity of the target PSCell; a measurement result of the target PCell; information for a time at which the execution condition was satisfied; information for an evaluation status of at least one of the first execution condition or the second execution condition when the mobility procedure failed; or information for a time gap between a time of the execution condition being satisfied and a time when the mobility procedure failed.

[0286] According to various embodiments, the communication device may select a cell based on initiating the RRC re-establishment procedure. The communication device may transmit, to a network through the selected cell, an RRC re-establishment request message. The communication device may receive, from the network, an RRC re-establishment message. The communication device may transmit, to the network, an RRC re-establishment complete message comprising first availability information informing that the mobility failure information is available in the communication device.

[0287] According to various embodiments, after transmitting the first availability information, the communication device may receive, from the network, user equipment (UE) information request message comprising a request for the mobility failure information. The communication device may transmit, to the network, UE information response message comprising the mobility failure information.

[0288] According to various embodiments, the mobility procedure may end in success. The mobility information may comprise mobility success information (e.g., successful handover information) comprising the first information and the second information.

[0289] According to various embodiments, the communication device may log the mobility success information based on a success of the mobility procedure.

[0290] For example, the communication device may start T304 timer based on initiating the mobility procedure (i.e., applying cell configuration / RRC reconfiguration), with a timer value included in the cell configuration / RRC reconfiguration. Based on the success of the mobility procedure, the communication device may stop the T304 timer. If a ratio between a value of an elapsed time of the T304 timer (e.g., from the start to stop of the T304 timer) to the timer value of the T304 timer is greater than a threshold (e.g.,thresholdPercentageT304included insuccessHO-Config) received from a network before initiating the mobility procedure, the communication device may log the mobility success information.

[0291] According to various embodiments, the logged mobility success information may further comprise at least one of: a cell identity of at least one of a source PCell or the target PCell; a measurement result of at least one of the source PCell or the target PCell; a cell identity of at least one of a source PSCell or the target PSCell; a measurement result of at least one of the source PSCell or the target PCell; information for a time at which the execution condition was satisfied; or information for an evaluation status of at least one of the first execution condition or the second execution condition when the mobility procedure succeeded.

[0292] According to various embodiments, the communication device may transmit, to a network, a radio resource control (RRC) reconfiguration complete message based on a success of the mobility procedure. The RRC reconfiguration complete message may comprise second availability information informing that the mobility success information is available in the communication device.

[0293] According to various embodiments, after transmitting the second availability information, the communication device may receive, from the network, user equipment (UE) information request message comprising a request for the mobility success information. The communication device may transmit, to the network, UE information response message comprising the mobility success information.

[0294] According to various embodiments, the UE may detect a failure of a mobility on a PCell after reception of conditional mobility configuration (or, conditional reconfiguration) related to the mobility. The conditional mobility configuration may comprise one or more cell configurations for PCell(s) and corresponding conditions (i.e., execution conditions) to apply the one or more cell configurations for PCell(s). The conditional mobility configuration may (further) comprise one or more cell configurations for PSCell(s) and corresponding conditions (e.g., execution conditions) to apply the one or more cell configurations for PSCell(s). The UE may log mobility failure information including information related to the one or more cell configurations for PSCell(s) and corresponding conditions to apply the one or more cell configurations for PSCell(s). The information may comprise which condition is first met between PCell and PSCell, and / or how much time has elapsed since the condition was first met. The UE may report the mobility failure information when the UE is requested from the network to retrieve the mobility failure information.

[0295] According to various embodiments, the UE may receive conditional mobility configuration (i.e., conditional reconfiguration) related to a mobility. The conditional mobility configuration may comprise one or more cell configurations for PCell(s) and corresponding conditions (i.e., execution conditions) to apply the one or more cell configurations for PCell(s). The conditional mobility configuration may (further) comprise one or more cell configurations for PSCell(s) and corresponding conditions (e.g., execution conditions) to apply the one or more cell configurations for PSCell(s). Upon successfully performing the mobility to PCell, the UE may log mobility success information comprising information related to the one or more cell configurations for PSCell(s) and corresponding conditions to apply the one or more cell configurations for PSCell(s). The information may comprise which condition is first met between PCell and PSCell and how much time has elapsed since the condition was first met. The information may (further) comprise signal quality of source PSCell and target PSCell to compare which SCG was better when performing the mobility. The UE may report the mobility success information when the UE is requested from the network to retrieve the mobility success information.

[0296] FIG. 11 shows an example of a signal flow between a communication device and a network node according to an embodiment of the present disclosure. The network node may comprise a base station (BS).

[0297] Referring to FIG. 11, in step S1101, the network node may transmit, to a communication device, a measurement configuration.

[0298] In step S1103, the network node may receive, from the communication device, a measurement report.

[0299] In step S1105, the network node may transmit, to the communication device, a conditional reconfiguration comprising execution conditions for mobility including i) a first execution condition for a PCell mobility to a target PCell, and ii) a second execution condition for a PSCell mobility to a target PSCell associated with the target PCell.

[0300] In step S1107, the communication device may evaluate the execution conditions including the first execution condition for the target PCell and the second execution condition for the associated target PSCell.

[0301] In step S1109, the communication device may perform a mobility procedure based on one or more execution conditions among the execution conditions being satisfied.

[0302] In step S1111, after the mobility procedure ends, the communication device may transmit mobility information comprising: first information for an execution condition that is satisfied first among the first execution condition and the second execution condition; and second information for a time duration that has elapsed since the execution condition was satisfied.

[0303] According to implementations of the present disclosure, when a mobility failure on PCell (or, MCG) or radio link failure on PCell (or, MCG) occurs, the UE may determine whether the UE logs information related to configuration of CPA or CPC that is associated with CHO. For the determination, after / when a mobility failure on PCell or radio link failure occurs on PCell, the UE may check whether there is a CHO configuration and an associated SCG configuration or associated CPA / CPC configuration that can be applied together with the CHO. If there is at least one SCG configuration or CPA / CPC configuration that can be applied together with the CHO, the UE may log information about the SCG configuration or CPA / CPC configuration that can be applied together with the CHO when logging the mobility failure on the PCell or radio link failure on the PCell.

[0304] If there is an SCG configuration or CPA / CPC configuration that can be applied together with the CHO configuration, the UE may include / log the following logging information in an RLF report (or, mobility failure information) during the RLF logging procedure (i.e., RLF report logging):

[0305] 1) Logging for each evaluation status of CHO execution condition and CPA / CPC execution condition

[0306] A. Which execution condition was met first: This information may be included in the logging information to inform the network of which execution condition was satisfied first if there was at least one satisfied execution condition before / when declaration of mobility failure on PCell or radio link failure on PCell; and / or

[0307] B. Which execution condition was not met: This information is included in the logging information to inform the network of which execution condition(s) was(were) not satisfied among all execution conditions of CHO and CPA / CPC configuration before / when declaration of mobility failure on PCell or radio link failure on PCell. When logging the execution condition that is not satisfied, the UE can also log the details of the execution condition, such as TTT status, entering condition status (i.e., whether an entering condition of the execution condition is satisfied / how long the entering condition is satisfied among TTT for the execution condition, or how short a duration is left after a duration the entering condition is satisfied among the TTT) and / or leaving condition status (i.e., whether a leaving condition of the execution condition is satisfied / how long the leaving condition is satisfied among TTT for the execution condition, or how short a duration is left after a duration the leaving condition is satisfied among the TTT).

[0308] 2) Time information for satisfied and / or unsatisfied execution conditions

[0309] A. Time gap with the (un)satisfied execution condition: This information is included in the logging information to inform the network of the elapsed time between the execution condition being satisfied and the failure declaration if there was at least one satisfied execution condition before / when mobility failure on PCell or radio link failure on PCell.

[0310] B. Time of satisfied execution condition: This information is included in the logging information to inform the network of the time when the execution condition was first met if there was at least one satisfied execution condition before failure declaration for CHO execution and CPA / CPC execution.

[0311] 3) Measurement results of target / candidate PSCell quality and / or each cell identity

[0312] A. All candidate PSCell signal quality related to failed target PSCell signal quality: This information is included in the logging information by the UE to inform the network of the signal quality of the target PSCell and / or all candidate PSCell signal qualities that were provided together with the CPC / CPA configuration before / when mobility failure on PCell or radio link failure on PCell. The UE may also include the PSCell signal quality of the SCG configuration that can be applied together with the CHO configuration, in the logging information.

[0313] The UE may declare a PCell mobility failure when the validity timer (i.e., T304 timer) provided for any PCell mobility, including CHO, expires.

[0314] The UE may declare a radio link failure on PCell in the following cases:

[0315] 1) upon T310 timer expiry in PCell; or

[0316] 2) upon T312 timer expiry in PCell; or

[0317] 3) upon random access problem indication from MCG MAC while neither T300, T301, T304, T311 nor T319 are running and small data transmission (SDT) procedure is not ongoing; or

[0318] 4) upon indication from MCG RLC that the maximum number of retransmissions has been reached while SDT procedure is not ongoing.

[0319] FIG. 12 shows an example of a procedure for logging of mobility information after the mobility failure according to an embodiment of the present disclosure.

[0320] Referring to FIG. 12, in step S1201, the UE may receive CHO configuration and associated SCG configuration (i.e., SCG configuration associated with the CHO configuration) and / or associated CPA / CPC configuration (i.e., CPA / CPC configuration associated with the CHO configuration) that can be applied together with the CHO configuration, from the network. The network may provide the CHO configuration to the UE viaconditionalReconfigurationinformation in the RRC reconfiguration message. The SCG configuration or the CPA / CPC configuration that can be applied together with the CHO configuration can also be provided viaconditionalReconfigurationinformation. In the case of the associated CPA / CPC configuration that can be applied together with the CHO configuration, the execution condition for performing CPA / CPC is also provided.

[0321] For example, the UE may be provided with:

[0322] - CHO configuration for candidate A comprising CHO execution condition for candidate A & associated CPA / CPC configuration for PSCell associated with candidate A comprising CPA / CPC execution condition for PSCell associated with candidate A;

[0323] - CHO configuration for candidate B comprising CHO execution condition for candidate B & associated CPA / CPC configuration for PSCell associated with candidate B comprising CPA / CPC execution condition for PSCell associated with candidate B; and

[0324] - CHO configuration for candidate C comprising CHO execution condition for candidate C & associated SCG configuration for PSCell associated with candidate C.

[0325] In steps S1203, after receiving the CHO configuration, associated SCG configuration and / or associated CPC / CPA configuration, the UE may start evaluating CHO execution condition(s) for each candidate cell A, B and C for CHO. The UE may also start evaluating execution condition(s) for CPA / CPC provided to be performed together with CHO (e.g., CPA / CPC execution condition for PSCell associated with candidate A, CPA / CPC execution condition for PSCell associated with candidate B).

[0326] The UE may confirm that the CHO execution condition for candidate A in the CHO configuration provided together with the CPA / CPC configuration has been met. However, the UE may confirm that the execution condition for applying the associated CPA / CPC configuration has not been met yet and does not perform CHO.

[0327] The UE may confirm that the execution condition for applying the associated CPA / CPC configuration provided together with the CHO configuration has been met for PSCell associated with candidate B, but the CHO execution condition for candidate B has not been met, so the UE does not perform CHO.

[0328] The UE may confirm that the CHO execution condition has been met for candidate C. The UE may also confirm that there is no associated CPA / CPC configuration for candidate C. But associated SCG configuration was provided for candidate C, and this associated SCG configuration can be applied if only the CHO execution condition is met. Therefore, in step S1205, the UE may perform CHO towards candidate C with the associated SCG configuration (i.e., with applying the associated SCG configuration). The UE may start the T304 timer for mobility validity check while performing the CHO.

[0329] The UE may detect access failure (e.g., random access failure) and / or T304 timer expiry if the UE fails to synchronize with candidate C based on the CHO configuration with the SCG configuration until the T304 timer expires.

[0330] In step S1207, the UE may declare a mobility failure (e.g., handover failure) and initiate the RRC re-establishment procedure.

[0331] In step S1209, the UE may start RLF report logging before / when initiating the RRC re-establishment procedure. During the RLF report logging process, the UE may log information (e.g., mobility failure information) about candidate A, candidate B, and / or candidate C (which was a target cell).

[0332] For example, logging condition for the mobility failure information is described. The UE shall:

[0333] 1> if T304 of the MCG expires; or

[0334] 1> if T420 expires; or,

[0335] 1> if the target L2 U2N Relay UE (i.e., the UE indicated bytargetRelayUE-Identityin the receivedRRCReconfigurationmessage containingreconfigurationWithSyncindicating path switch changes its serving PCell before path switch:

[0336] 2> release dedicated preambles provided inrach-ConfigDedicatedif configured;

[0337] 2> release dedicated msgA PUSCH resources provided inrach-ConfigDedicatedif configured;

[0338] 2> if any DAPS bearer is configured, and radio link failure is not detected in the source PCell, according to clause 5.3.10.3:

[0339] 3> reset MAC for the target PCell and release the MAC configuration for the target PCell;

[0340] 3> for each DAPS bearer:

[0341] 4> release the RLC entity or entities and the associated logical channel for the target PCell;

[0342] 4> reconfigure the PDCP entity to release DAPS;

[0343] 3> for each SRB:

[0344] 4> if themasterKeyUpdatewas not received:

[0345] 5> configure the PDCP entity for the source PCell with state variables continuation;

[0346] 4> release the PDCP entity for the target PCell;

[0347] 4> release the RLC entity and the associated logical channel for the target PCell;

[0348] 4> trigger the PDCP entity for the source PCell to perform SDU discard;

[0349] 4> re-establish the RLC entity for the source PCell;

[0350] 3> release the physical channel configuration for the target PCell;

[0351] 3> discard the keys used in target PCell (the KgNBkey, the KRRCenckey, the KRRCintkey, the KUPintkey and the KUPenckey), if any;

[0352] 3> resume suspended SRBs in the source PCell;

[0353] 3> for each non-DAPS bearer:

[0354] 4> revert back to the UE configuration used for the DRB or multicast MRB in the source PCell, includes PDCP, RLC states variables, the security configuration and the data stored in transmission and reception buffers in PDCP and RLC entities ;

[0355] 3> revert back to the UE measurement configuration used in the source PCell;

[0356] 3> store / log the mobility failure information (e.g., handover failure information) inVarRLF-Report.

[0357] 2> else:

[0358] 3> revert back to the UE configuration used in the source PCell;

[0359] 3> if the associated T304 was not initiated upon cell selection performed while timer T311 was running:

[0360] 4> store / log the mobility failure information (e,g., handover failure information) inVarRLF-Report.When logging information about candidate A, the UE may log a cell identity and a measurement result of candidate A along with information that the CHO execution condition was first met and the time at which the CHO execution condition was satisfied. The information may also comprise the evaluation results (e.g., measurement result of the candidate PSCell for CPA / CPC) based on the time of T304 expiry (i.e., the time to declare the associated CPA / CPC execution condition was not met). The UE may also log the time gap between the execution condition being satisfied and T304 expiry.

[0361] When logging information about candidate B, the UE may log a cell identity and a measurement result of candidate B along with information that the CPA / CPC execution condition was first met and the time at which the CPA / CPC execution condition was satisfied. The information may also comprise the evaluation results (e.g., measurement result of the candidate PCell (or, candidate B) for CHO) based on the time of T304 expiry (i.e., the time to declare the associated CHO execution condition was not met). The UE may also log the time gap between the execution condition being satisfied and T304 expiry.

[0362] When logging information about candidate C, the UE may log the time at which the corresponding CHO execution condition was met, the cell identity and the measurement result of candidate C at that time, and a PSCell signal quality of a PSCell related to the SCG configuration that was applied together with the CHO configuration for candidate C at that time, at the time of T304 expiry.

[0363] In step S1211, the UE may transmit / receive signalings related to the RRC re-establishment procedure through a selected cell. The UE may select a new cell instead of selecting an appropriate candidate cell for CHO recovery through the cell selection procedure and send an RRC re-establishment request to the network. The UE may receive an RRC re-establishment message from the network and respond with an RRC re-establishment complete message, includingrlf-InfoAvailablefor logging RLF reporting. Therlf-InfoAvailablemay indicate that the UE has the RLF report (or, mobility failure information) to be reported to the network.

[0364] In step S1213, the UE may perform a UE information procedure. The UE may receive a UE information request message comprising a request for RLF report logging (or, logged RLF report / mobility failure information) from the network. The network may request RLF report logging (or, logged RLF report / mobility failure information) viarlf-ReportReqincluded in the UE Information request message. The UE may transmit a UE information response message for reporting the logged information (e.g., RLF report / mobility failure information) related to candidate A, candidate B and / or candidate C.

[0365] According to implementations of the present disclosure, after successfully completing PCell mobility, the UE may decide whether to log information related to the CPA or CPC configuration that was configured with CHO configuration. For the determination, the UE may check whether there is a CPA / CPC configuration and / or SCG configuration associated with each candidate cell of CHO when PCell mobility is successfully completed. If there is at least one SCG configuration or CPA / CPC configuration that can be applied with CHO configuration, the UE may log information about the SCG configuration and / or CPA / CPC configuration with the source PSCell information when PCell mobility is successfully completed.

[0366] If there is an SCG configuration or CPA / CPC configuration that can be applied together with the CHO configuration, the UE may include / log the following logging information in mobility information (e.g.,mobilityHistoryReportorSuccessHO-Report):

[0367] 1) Cell identity and signal quality of the selected target PCell:

[0368] This logging information is to inform the network of the signal quality of the target PCell when the UE performs handover.

[0369] 2) Cell identity and signal quality of all PSCells associated with the selected target PCell:

[0370] This logging information is to inform the network of the signal quality of the PSCell that will be applicated with the target PCell. If there is more than one PSCell in CPA / CPC configuration or SCG configuration that can be applied with the CHO configuration for the target PCell, the UE may log the signal quality of all related PSCells and include indication to discriminate which PSCell is currently applied.

[0371] 3) Cell identity and signal quality of the source PSCell:

[0372] This logging information is to inform the network of the signal quality of the source PSCell when the UE performs handover. If the PSCell that will be applied with the target PCell is the same as the source PSCell, the UE may not log signal quality of the source PSCell to avoid duplicate information.

[0373] 4) Cell identity and signal quality of the source PCell:

[0374] This logging information is to inform the network of the signal quality of the source PCell when the UE performs handover. If the target PCell is the same as the source PCell, the UE may not log signal quality of the source PCell to avoid duplicate information.

[0375] 5) Logging for each evaluation status of CHO execution condition and CPA / CPC execution condition

[0376] A. Which execution condition was met first: This information may be included in the logging information to inform the network of which execution condition was satisfied first if there was at least one satisfied execution condition before / when declaration of mobility failure on PCell or radio link failure on PCell; and / or

[0377] B. Which execution condition was not met: This information is included in the logging information to inform the network of which execution condition(s) was(were) not satisfied among all execution conditions of CHO and CPA / CPC configuration before / when performing the mobility towards PCell. When logging the execution condition that is not satisfied, the UE can also log the details of the execution condition, such as TTT status, entering condition status (i.e., whether an entering condition of the execution condition is satisfied / how long the entering condition is satisfied among TTT for the execution condition, or how short a duration is left after a duration the entering condition is satisfied among the TTT) and / or leaving condition status (i.e., whether a leaving condition of the execution condition is satisfied / how long the leaving condition is satisfied among TTT for the execution condition, or how short a duration is left after a duration the leaving condition is satisfied among the TTT).

[0378] 6) Time information between the two satisfied execution conditions

[0379] A. Time gap between the satisfied execution conditions: This information is included in the logging information to inform the network of the elapsed time between the execution condition being satisfied first and the execution condition being satisfied second for CHO and the associated CPA / CPC if the mobility is executed for CHO and the associated CPA / CPC.

[0380] B. Time of satisfied execution condition: This information is included in the logging information to inform the network of the time when the execution condition was first met if there was at least one satisfied execution condition before / when performing the mobility towards PCell.

[0381] 7) Measurement results of target / candidate PSCell quality and / or each cell identity

[0382] A. All candidate PSCell signal quality related to failed target PSCell signal quality: This information is included in the logging information by the UE to inform the network of the signal quality of the target PSCell and / or all candidate PSCell signal qualities that were provided together with the CPC / CPA configuration before / when performing the mobility towards PCell. The UE may also include the PSCell signal quality of the SCG configuration that can be applied together with the CHO configuration, in the logging information.

[0383] FIG. 13 shows an example of a procedure for logging of mobility information after the mobility failure according to an embodiment of the present disclosure.

[0384] Referring to FIG. 13, in step S1301, the UE may receive CHO configuration and associated SCG configuration (i.e., SCG configuration associated with the CHO configuration) and / or associated CPA / CPC configuration (i.e., CPA / CPC configuration associated with the CHO configuration) that can be applied together with the CHO configuration, from the network. The network may provide the CHO configuration to the UE viaconditionalReconfigurationinformation in the RRC reconfiguration message. The SCG configuration or the CPA / CPC configuration that can be applied together with the CHO configuration can also be provided viaconditionalReconfigurationinformation. In the case of the associated CPA / CPC configuration that can be applied together with the CHO configuration, the execution condition for performing CPA / CPC is also provided.

[0385] For example, the UE may be provided with:

[0386] - CHO configuration for candidate A comprising CHO execution condition for candidate A & associated CPA / CPC configuration for PSCell associated with candidate A comprising CPA / CPC execution condition for PSCell associated with candidate A;

[0387] - CHO configuration for candidate B comprising CHO execution condition for candidate B & associated CPA / CPC configuration for PSCell associated with candidate B comprising CPA / CPC execution condition for PSCell associated with candidate B; and

[0388] - CHO configuration for candidate C comprising CHO execution condition for candidate C & associated SCG configuration for PSCell associated with candidate C.

[0389] In steps S1303, after receiving the CHO configuration, associated SCG configuration and / or associated CPC / CPA configuration, the UE may start evaluating CHO execution condition(s) for each candidate cell A, B and C for CHO. The UE may also start evaluating execution condition(s) for CPA / CPC provided to be performed together with CHO (e.g., CPA / CPC execution condition for PSCell associated with candidate A, CPA / CPC execution condition for PSCell associated with candidate B).

[0390] The UE may confirm that the CHO execution condition for candidate A in the CHO configuration provided together with the CPA / CPC configuration has been met. However, the UE may confirm that the execution condition for applying the associated CPA / CPC configuration has not been met yet and does not perform CHO.

[0391] The UE may confirm that the execution condition for applying the associated CPA / CPC configuration provided together with the CHO configuration has been met for PSCell associated with candidate B, but the CHO execution condition for candidate B has not been met, so the UE does not perform CHO.

[0392] The UE may confirm that the CHO execution condition has been met for candidate C. The UE may also confirm that there is no associated CPA / CPC configuration for candidate C. But associated SCG configuration was provided for candidate C, and this associated SCG configuration can be applied if only the CHO execution condition is met. Therefore, in step S1305, the UE may perform CHO towards candidate C with the associated SCG configuration (i.e., with applying the associated SCG configuration). The UE may start the T304 timer for mobility validity check while performing the CHO.

[0393] In step S1307, the UE may successfully access on the candidate C as target cell of the mobility based on the CHO configuration with the SCG configuration, and stop the T304 timer.

[0394] In step S1309, the UE may log mobility complete (e.g., mobility success information) usingmobilityHistoryReportorSuccessHO-Report. During mobility complete logging process, the UE may log information (e.g., mobility success information) about candidate A, candidate B, and / or candidate C (which was a target cell), with source PCell and source PSCell.

[0395] For example, logging condition for the mobility success information is described. The UE shall for the PCell:

[0396] 1> if the ratio between the value of the elapsed time of the timer T304 and the configured value of the timer T304, included in the last appliedRRCReconfigurationmessage including thereconfigurationWithSync, is greater thanthresholdPercentageT304if included in thesuccessHO-Configreceived before executing the last reconfiguration with sync; or

[0397] 1> if the ratio between the value of the elapsed time of the timer T310 and the configured value of the timer T310, configured while the UE was connected to the source PCell before executing the last reconfiguration with sync, is greater thanthresholdPercentageT310included in thesuccessHO-Configif configured by the source PCell before executing the last reconfiguration with sync; or

[0398] 1> if the T312 associated to the measurement identity of the target cell was running at the time of initiating the execution of the reconfiguration with sync procedure and if the ratio between the value of the elapsed time of the timer T312 and the configured value of the timer T312, configured while the UE was connected to the source PCell before executing the last reconfiguration with sync, is greater thanthresholdPercentageT312included in the successHO-Configif configured by the source PCell before executing the last reconfiguration with sync; or

[0399] 1> ifsourceDAPS-FailureReportingis included in thesuccessHO-Configbefore executing the last reconfiguration with sync and is set totrueand if the last executed handover was a DAPS handover and if an RLF occurred at the source PCell during the DAPS handover while T304 was running:

[0400] 2> store / log the mobility success information (e.g., successful handover information) inVarSuccessHO-Report.

[0401] When logging information about candidate A, the UE may log a cell identity and a measurement result of candidate A along with information that the CHO execution condition was first met and the time at which the CHO execution condition was satisfied. The information may also comprise the evaluation results (e.g., measurement result of the candidate PSCell for CPA / CPC) based on the time when performing the mobility towards PCell.

[0402] When logging information about candidate B, the UE may log a cell identity and a measurement result of candidate B along with information that the CPA / CPC execution condition was first met and the time at which the CPA / CPC execution condition was satisfied. The information may also comprise the evaluation results (e.g., measurement result of the candidate PCell (or, candidate B) for CHO) based on the time when performing the mobility towards PCell.

[0403] When logging information about candidate C, the UE may log the time at which the corresponding CHO execution condition was met, the cell identity and the measurement result of candidate C at that time, and a PSCell signal quality of a PSCell related to the SCG configuration that was applied together with the CHO configuration for candidate C at that time, at the time of performing the mobility towards PCell.

[0404] Then, the UE may confirm that the new PSCell in the SCG configuration applied with the source PSCell and / or candidate C (e.g., CHO configuration for candidate C) is different from the source PSCell, and log the cell identity of the source PSCell and the measurement result related to the source PSCell (e.g., signal quality of the source PSCell) at the time of performing PCell mobility.

[0405] In step S1311, the UE may send RRC reconfiguration complete message to indicate that PCell mobility is successfully completed on the candidate C. The RRC reconfiguration complete message may comprisemobilityHistoryAvailorsuccessHO-InfoAvailablefor the mobility complete logging (or, mobility success information). For example, themobilityHistoryAvailorsuccessHO-InfoAvailableindicate that the UE has the mobility success information to be reported to the network. The UE may also perform logging after sending the RRC reconfiguration complete message.

[0406] In step S1313, the UE may perform a UE information procedure. The UE may receive a UE information request message comprising a request for the mobility complete logging (or, mobility success information) from the network. The network may request the mobility complete logging (or, the mobility success information) viamobilityHistoryReportReqorsuccessHO-ReportReqincluded in the UE Information request message. The UE may transmit a UE information response message for reporting the logged information (e.g., mobility success information) related to candidate A, candidate B and / or candidate C, with source PSCell.

[0407] Furthermore, the method in perspective of the communication device described in the present disclosure (e.g., in FIG. 10) may be performed by the first wireless device 100 shown in FIG. 2 and / or the UE 100 shown in FIG. 3.

[0408] More specifically, the communication device comprises at least one transceiver, at least processor, and at least one computer memory operably connectable to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations.

[0409] The operations comprise: receiving a conditional reconfiguration comprising execution conditions for mobility including i) a first execution condition for a PCell mobility to a target PCell, and ii) a second execution condition for a PSCell mobility to a target PSCell associated with the target PCell; evaluating the execution conditions including the first execution condition for the target PCell and the second execution condition for the associated target PSCell; performing a mobility procedure based on one or more execution conditions among the execution conditions being satisfied; and after the mobility procedure ends, transmitting mobility information comprising: first information for an execution condition that is satisfied first among the first execution condition and the second execution condition; and second information for a time duration that has elapsed since the execution condition was satisfied.

[0410] Furthermore, the method in perspective of the communication device described in the present disclosure (e.g., in FIG. 10) may be performed by a software code 105 stored in the memory 104 included in the first wireless device 100 shown in FIG. 2.

[0411] More specifically, at least one computer readable medium (CRM) stores instructions that, based on being executed by at least one processor, perform operations comprising: receiving a conditional reconfiguration comprising execution conditions for mobility including i) a first execution condition for a PCell mobility to a target PCell, and ii) a second execution condition for a PSCell mobility to a target PSCell associated with the target PCell; evaluating the execution conditions including the first execution condition for the target PCell and the second execution condition for the associated target PSCell; performing a mobility procedure based on one or more execution conditions among the execution conditions being satisfied; and after the mobility procedure ends, transmitting mobility information comprising: first information for an execution condition that is satisfied first among the first execution condition and the second execution condition; and second information for a time duration that has elapsed since the execution condition was satisfied.

[0412] Furthermore, the method in perspective of the communication device described in the present disclosure (e.g., in FIG. 10) may be performed by control of the processor 102 included in the first wireless device 100 shown in FIG. 2 and / or by control of the processor 102 included in the UE 100 shown in FIG. 3.

[0413] More specifically, an apparatus configured to / adapted to operate in a wireless communication system (e.g., communication device / UE) comprises at least processor, and at least one computer memory operably connectable to the at least one processor. The at least one processor is configured to / adapted to perform operations comprising: receiving a conditional reconfiguration comprising execution conditions for mobility including i) a first execution condition for a PCell mobility to a target PCell, and ii) a second execution condition for a PSCell mobility to a target PSCell associated with the target PCell; evaluating the execution conditions including the first execution condition for the target PCell and the second execution condition for the associated target PSCell; performing a mobility procedure based on one or more execution conditions among the execution conditions being satisfied; and after the mobility procedure ends, transmitting mobility information comprising: first information for an execution condition that is satisfied first among the first execution condition and the second execution condition; and second information for a time duration that has elapsed since the execution condition was satisfied.

[0414] Furthermore, the method in perspective of a network node described in the present disclosure (e.g., in FIG. 11) may be performed by the second wireless device 200 shown in FIG. 2. The network node may be related to a serving cell.

[0415] More specifically, the network node comprises at least one transceiver, at least processor, and at least one computer memory operably connectable to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations.

[0416] The operations comprise: transmitting, to a communication device, a measurement configuration; receiving, from the communication device, a measurement report; and transmitting, to the communication device, a conditional reconfiguration comprising execution conditions for mobility including i) a first execution condition for a PCell mobility to a target PCell, and ii) a second execution condition for a PSCell mobility to a target PSCell associated with the target PCell, wherein the communication device is adapted to perform operations comprising: evaluating the execution conditions including the first execution condition for the target PCell and the second execution condition for the associated target PSCell; performing a mobility procedure based on one or more execution conditions among the execution conditions being satisfied; and after the mobility procedure ends, transmitting mobility information comprising: first information for an execution condition that is satisfied first among the first execution condition and the second execution condition; and second information for a time duration that has elapsed since the execution condition was satisfied.

[0417] The present disclosure may have various advantageous effects.

[0418] For example, network can update CPA / CPC information for other UEs in similar situations to more appropriately apply the CPA / CPC configuration. This can prevent mobility failures from other UEs caused by the same reason in the future.

[0419] For example, the network can consider information regarding CPA / CPC configuration which is associated with CHO configuration when the UE successfully performs PCell mobility. Therefore, the network can update and provide the CPA / CPC configuration more appropriately to other UEs in similar situations to prevent SCG failure cases or additional PSCell changes to find a better PSCell.

[0420] Advantageous effects which can be obtained through specific embodiments of the present disclosure are not limited to the advantageous effects listed above. For example, there may be a variety of technical effects that a person having ordinary skill in the related art can understand and / or derive from the present disclosure. Accordingly, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that may be understood or derived from the technical features of the present disclosure.

[0421] Claims in the present disclosure can be combined in a various way. For instance, technical features in method claims of the present disclosure can be combined to be implemented or performed in an apparatus, and technical features in apparatus claims can be combined to be implemented or performed in a method. Further, technical features in method claim(s) and apparatus claim(s) can be combined to be implemented or performed in an apparatus. Further, technical features in method claim(s) and apparatus claim(s) can be combined to be implemented or performed in a method. Other implementations are within the scope of the following claims.

Claims

1.A method performed by a communication device adapted to operate in a wireless communication system, the method comprising:receiving a conditional reconfiguration comprising execution conditions for mobility including i) a first execution condition for a PCell mobility to a target PCell, and ii) a second execution condition for a PSCell mobility to a target PSCell associated with the target PCell;evaluating the execution conditions including the first execution condition for the target PCell and the second execution condition for the associated target PSCell;performing a mobility procedure based on one or more execution conditions among the execution conditions being satisfied; andafter the mobility procedure ends, transmitting mobility information comprising:first information for an execution condition that is satisfied first among the first execution condition and the second execution condition; andsecond information for a time duration that has elapsed since the execution condition was satisfied.2.The method of claim 1, wherein, based on the target PSCell being associated with the target PCell:a mobility towards the target PCell and a mobility towards the target PSCell are performed together when both of the first execution condition for the target PCell and the second execution condition for the target PSCell are satisfied; andneither the mobility towards the target PCell nor the mobility towards the target PSCell is performed when at least one of the first execution condition for the target PCell or the second execution condition for the target PSCell is satisfied.3.The method of claim 1, wherein the mobility procedure ends in failure, andwherein the mobility information comprises mobility failure information comprising the first information and the second information.4.The method of claim 3, further comprising:initiating a radio resource control (RRC) re-establishment procedure based on a failure of the mobility procedure; andlogging the mobility failure information based on initiating the RRC re-establishment procedure.5.The method of claim 4, wherein the logged mobility failure information further comprises at least one of:a cell identity of the target PCell;a measurement result of the target PCell;a cell identity of the target PSCell;a measurement result of the target PCell;information for a time at which the execution condition was satisfied;information for an evaluation status of at least one of the first execution condition or the second execution condition when the mobility procedure failed; orinformation for a time gap between a time of the execution condition being satisfied and a time when the mobility procedure failed.6.The method of claim 4, further comprising:selecting a cell based on initiating the RRC re-establishment procedure;transmitting, to a network through the selected cell, an RRC re-establishment request message;receiving, from the network, an RRC re-establishment message; andtransmitting, to the network, an RRC re-establishment complete message comprising first availability information informing that the mobility failure information is available in the communication device.7.The method of claim 6, further comprising:after transmitting the first availability information, receiving, from the network, user equipment (UE) information request message comprising a request for the mobility failure information; andtransmitting, to the network, UE information response message comprising the mobility failure information.8.The method of claim 1, wherein the mobility procedure ends in success, andwherein the mobility information comprises mobility success information comprising the first information and the second information.9.The method of claim 8, further comprising:logging the mobility success information based on a success of the mobility procedure.10.The method of claim 9, further comprising:starting a timer with a timer value based on initiating the mobility procedure;performing the mobility procedure while the timer is running; andstopping the timer based on the success of the mobility procedure,wherein the mobility success information is logged based on a ratio between a value of an elapsed time of the timer until the timer stops from the start of the timer to the timer value being greater than a threshold received from a network before initiating the mobility procedure.11.The method of claim 9, wherein the logged mobility success information further comprises at least one of:a cell identity of at least one of a source PCell or the target PCell;a measurement result of at least one of the source PCell or the target PCell;a cell identity of at least one of a source PSCell or the target PSCell;a measurement result of at least one of the source PSCell or the target PCell;information for a time at which the execution condition was satisfied; orinformation for an evaluation status of at least one of the first execution condition or the second execution condition when the mobility procedure succeeded.12.The method of claim 8, further comprising:transmitting, to a network, a radio resource control (RRC) reconfiguration complete message based on a success of the mobility procedure,wherein the RRC reconfiguration complete message comprises second availability information informing that the mobility success information is available in the communication device.13.The method of claim 12, further comprising:after transmitting the second availability information, receiving, from the network, user equipment (UE) information request message comprising a request for the mobility success information; andtransmitting, to the network, UE information response message comprising the mobility success information.14.The method of claims 1, wherein the communication device is in communication with at least one of a user equipment (UE), a mobile device, a network, or autonomous vehicles.15.A communication device configured to operate in a wireless communication system, the UE comprising:at least one transceiver;at least one processor; andat least one memory operatively coupled to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations comprising:receiving a conditional reconfiguration comprising execution conditions for mobility including i) a first execution condition for a PCell mobility to a target PCell, and ii) a second execution condition for a PSCell mobility to a target PSCell associated with the target PCell;evaluating the execution conditions including the first execution condition for the target PCell and the second execution condition for the associated target PSCell;performing a mobility procedure based on one or more execution conditions among the execution conditions being satisfied; andafter the mobility procedure ends, transmitting mobility information comprising:first information for an execution condition that is satisfied first among the first execution condition and the second execution condition; andsecond information for a time duration that has elapsed since the execution condition was satisfied.16.The communication device of claim 15, wherein the communication device is adapted to implement a method of one of claims 2 to 14.17.A network node configured to operate in a wireless communication system, the network node comprising:at least one transceiver;at least one processor; andat least one memory operatively coupled to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations comprising:transmitting, to a communication device, a measurement configuration;receiving, from the communication device, a measurement report; andtransmitting, to the communication device, a conditional reconfiguration comprising execution conditions for mobility including i) a first execution condition for a PCell mobility to a target PCell, and ii) a second execution condition for a PSCell mobility to a target PSCell associated with the target PCell,wherein the communication device is adapted to perform operations comprising:evaluating the execution conditions including the first execution condition for the target PCell and the second execution condition for the associated target PSCell;performing a mobility procedure based on one or more execution conditions among the execution conditions being satisfied; andafter the mobility procedure ends, transmitting mobility information comprising:first information for an execution condition that is satisfied first among the first execution condition and the second execution condition; andsecond information for a time duration that has elapsed since the execution condition was satisfied.18.A method performed by a network node configured to operate in a wireless communication system, the method comprising:transmitting, to a communication device, a measurement configuration;receiving, from the communication device, a measurement report; andtransmitting, to the communication device, a conditional reconfiguration comprising execution conditions for mobility including i) a first execution condition for a PCell mobility to a target PCell, and ii) a second execution condition for a PSCell mobility to a target PSCell associated with the target PCell,wherein the communication device is adapted to perform operations comprising:evaluating the execution conditions including the first execution condition for the target PCell and the second execution condition for the associated target PSCell;performing a mobility procedure based on one or more execution conditions among the execution conditions being satisfied; andafter the mobility procedure ends, transmitting mobility information comprising:first information for an execution condition that is satisfied first among the first execution condition and the second execution condition; andsecond information for a time duration that has elapsed since the execution condition was satisfied.19.An apparatus adapted to operate in a wireless communication system, the apparatus comprising:at least processor; andat least one memory operatively coupled to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations comprising:receiving a conditional reconfiguration comprising execution conditions for mobility including i) a first execution condition for a PCell mobility to a target PCell, and ii) a second execution condition for a PSCell mobility to a target PSCell associated with the target PCell;evaluating the execution conditions including the first execution condition for the target PCell and the second execution condition for the associated target PSCell;performing a mobility procedure based on one or more execution conditions among the execution conditions being satisfied; andafter the mobility procedure ends, transmitting mobility information comprising:first information for an execution condition that is satisfied first among the first execution condition and the second execution condition; andsecond information for a time duration that has elapsed since the execution condition was satisfied.20.A non-transitory computer readable medium (CRM) having stored thereon a program code implementing instructions that, based on being executed by at least one processor, perform operations comprising:receiving a conditional reconfiguration comprising execution conditions for mobility including i) a first execution condition for a PCell mobility to a target PCell, and ii) a second execution condition for a PSCell mobility to a target PSCell associated with the target PCell;evaluating the execution conditions including the first execution condition for the target PCell and the second execution condition for the associated target PSCell;performing a mobility procedure based on one or more execution conditions among the execution conditions being satisfied; andafter the mobility procedure ends, transmitting mobility information comprising:first information for an execution condition that is satisfied first among the first execution condition and the second execution condition; andsecond information for a time duration that has elapsed since the execution condition was satisfied.

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