Handling previous serving cells

Abstract

Methods and apparatus for handling a previous serving cell are provided. A wireless device receives a cell configuration for a first cell and receives a candidate cell configuration for a second cell. A second cell is added to a candidate cell list for mobility. Upon receiving the first mobility command, the wireless device applies a candidate cell configuration for the second cell, and the first cell is added to a candidate cell list for mobility. The wireless device reserves a cell configuration for the first cell and, upon receiving the second mobility command, applies the reserved cell configuration for the first cell.

Description

Technical Field

[0001] The present disclosure relates to handling previous serving cells. Background Art

[0002] The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a technology for implementing high-speed packet communications. Many solutions have been proposed for the LTE goal, including those aimed at reducing user and provider costs, improving service quality, and expanding and improving coverage and system capacity. 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of frequency bands, simple structure, open interfaces, and appropriate power consumption of terminals as higher-level requirements.

[0003] The International Telecommunication Union (ITU) and 3GPP have begun work to develop requirements and specifications for New Radio (NR) systems. 3GPP must identify and develop the technical components needed to successfully standardize a new RAT that meets both urgent market needs in a timely manner and longer-term requirements set forth by the ITU Radiocommunication Sector (ITU-R) International Mobile Telecommunications (IMT)-2020 process. In addition, even in the more distant future, NR should be able to use any spectrum band available for wireless communications up to at least 100 GHz.

[0004] NR targets a single technology framework that addresses all use cases, requirements, and deployment scenarios, including enhanced mobile broadband (eMBB), massive machine type communications (mMTC), ultra-reliable low latency communications (URLLC), etc. NR should be inherently forward compatible.

[0005] When a user equipment (UE) moves from the coverage area of ​​one cell to another, at some point a serving cell change needs to be performed. Currently, serving cell changes are triggered by L3 measurements and are done by reconfiguration triggered by radio resource control (RRC) signaling, with synchronization for changes to the primary cell (PCell) and primary secondary cell (PSCell), and release addition for the Scell ​​(when applicable). All cases involve a complete L2 (and L1) reset, resulting in longer latency, greater overhead, and longer outage time than beam switching mobility.

[0006] The goal of L1 / L2 mobility enhancement is to enable serving cell change via L1 / L2 signaling in order to reduce latency, overhead and interruption time. Summary of the invention

[0007] Technical Solution

[0008] The present disclosure provides a method and apparatus for handling a previous serving cell when performing low layer triggered mobility (LTM).

[0009] In one aspect, a method performed by a wireless device adapted to operate in a wireless communication system is provided. The method includes: receiving a cell configuration for a first cell; receiving a candidate cell configuration for a second cell, wherein the second cell is added to a candidate cell list for mobility. The method includes: upon receiving a first mobility command, applying the candidate cell configuration for the second cell, wherein the first cell is added to a candidate cell list for mobility. The method includes retaining the cell configuration for the first cell, and upon receiving a second mobility command, applying the retained cell configuration for the first cell.

[0010] In another aspect, a device for implementing the above method is provided.

[0011] Beneficial Effects

[0012] The present disclosure may have various beneficial effects.

[0013] For example, the UE may maintain source resources and configurations, and may perform TA maintenance and BFD / RLM after successful mobility execution.

[0014] For example, the UE may perform RACH-free mobility to a candidate serving cell.

[0015] For example, the delay and interruption time caused by the UE performing RACH can be reduced.

[0016] The beneficial effects that can be obtained by the specific embodiments of the present disclosure are not limited to the beneficial effects listed above. For example, there are various technical effects that a person of ordinary skill in the relevant field can understand and / or derive from the present disclosure. Therefore, the specific effects of the present disclosure are not limited to those effects explicitly described herein, but can include various effects that can be understood or derived from the technical features of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 An example of a communication system to which implementations of the present disclosure are applied is shown.

[0018] Figure 2 An example of a wireless device to which implementations of the present disclosure are applied is shown.

[0019] Figure 3 An example of a UE to which implementations of the present disclosure are applied is shown.

[0020] Figure 4 and Figure 5 An example of a protocol stack in a 3GPP-based wireless communication system to which implementations of the present disclosure are applied is shown.

[0021] Figure 6A frame structure in a 3GPP-based wireless communication system to which the present disclosure is applied is shown.

[0022] Figure 7 An example of data flow in a 3GPP NR system to which implementations of the present disclosure are applied is shown.

[0023] Figure 8 An example of a method performed by a wireless device to which an implementation of the present disclosure is applied is shown.

[0024] Fig. 9 An example of a method performed by a base station to which an implementation of the present disclosure is applied is shown. DETAILED DESCRIPTION

[0025] The following techniques, devices and systems can be applied to various wireless multiple access systems. Examples of these multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and multi-carrier frequency division multiple access (MC-FDMA) systems. CDMA can be implemented by radio technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented by radio technologies such as Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), or Enhanced Data Rate for GSM Evolution (EDGE). OFDMA can be implemented by radio technologies 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 part of 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 adopts OFDMA in the downlink (DL) and SC-FDMA in the uplink (UL). The evolutions of 3GPP LTE include LTE Advanced (LTE-A), LTE-A Pro and / or 5G New Radio (NR).

[0026] For ease of description, the embodiments of the present disclosure are mainly described with respect 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 a 3GPP-based wireless communication system are applicable to other mobile communication systems.

[0027] For terms and techniques not specifically described in the terms and techniques adopted in the present disclosure, reference may be made to wireless communication standard documents issued prior to the present disclosure.

[0028] In the present disclosure, "A or B" may mean "only A", "only B", or "both A and B". In other words, in the present disclosure, "A or B" may be interpreted as "A and / or B". For example, in the present disclosure, "A, B or C" may mean "only A", "only B", "only C", or "any combination of A, B, and C".

[0029] In the present disclosure, a slash ( / ) or a comma (,) may mean "and / or". For example, "A / B" may mean "A and / or B". Thus, "A / B" may mean "only A", "only B", or "both A and B". For example, "A, B, C" may mean "A, B, or C".

[0030] 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 being the same as "at least one of A and B".

[0031] 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".

[0032] In addition, the brackets 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, in the present disclosure, "control information" is not limited to "PDCCH", and "PDDCH" may be proposed as an example of "control information". In addition, even when it is shown as "control information (ie, PDCCH)", "PDCCH" may be proposed as an example of "control information".

[0033] The technical features described separately in one figure in the present disclosure can be implemented separately or simultaneously.

[0034] Although not limited to this, the various descriptions, functions, processes, suggestions, methods and / or operational flowcharts of the present disclosure disclosed herein may be applied to various fields requiring wireless communication and / or connection between devices (e.g., 5G).

[0035] Hereinafter, the present disclosure will be described in more detail with reference to the accompanying drawings. Unless otherwise specified, 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.

[0036] Figure 1 An example of a communication system to which an embodiment of the present disclosure is applied is shown.

[0037] exist Figure 1 The 5G usage scenarios shown in the present disclosure are only exemplary, and the technical features of the present disclosure may be applied to Figure 1 Other 5G usage scenarios shown in .

[0038] The three main demand categories for 5G include: (1) enhanced mobile broadband (eMBB) category, (2) massive machine type communication (mMTC) category, and (3) ultra-reliable and low-latency communication (URLLC) category.

[0039] Reference Figure 1 , the communication system 1 includes wireless devices 100a to 100f, a base station (BS) 200, and a network 300. Figure 1 A 5G network is illustrated as an example of a network of the communication system 1 , but the embodiments of the present disclosure are not limited to the 5G system and may be applied to future communication systems other than the 5G system.

[0040] BS 200 and network 300 may be implemented as wireless devices, and a specific wireless device may operate as a BS / network node relative to other wireless devices.

[0041] The wireless devices 100a to 100f represent devices that perform communication using a radio access technology (RAT) (e.g., 5G NR or LTE) and may be referred to as communication / wireless / 5G devices. The wireless devices 100a to 100f may include, but are not limited to, a robot 100a, vehicles 100b-1 and 100b-2, an extended reality (XR) device 100c, a handheld device 100d, a home appliance 100e, an Internet of Things (IoT) device 100f, and an artificial intelligence (AI) device / server 400. For example, a vehicle may include a vehicle with a wireless communication function, an autonomous vehicle, and a vehicle capable of performing communication between vehicles. A vehicle 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) installed in a vehicle, a television, a smart phone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, and the like. Handheld devices may include smart phones, smart tablets, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., notebooks). Home appliances may include TVs, refrigerators, and washing machines. IoT devices may include sensors and smart meters.

[0042] In the present disclosure, the wireless devices 100a to 100f may be referred to as user equipment (UE). For example, the UE may include a cellular phone, a smart phone, a laptop computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a plate-shaped personal computer (PC), a tablet PC, an ultrabook, a vehicle, a vehicle with an autonomous driving function, a connected car, a UAV, an AI module, a robot, an AR device, a VR device, an MR device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a Fintech device (or a financial device), a security device, a weather / environmental device, a device related to 5G services, or a device related to the field of the fourth industrial revolution.

[0043] The wireless devices 100a to 100f may be connected to the network 300 via the BS 200. 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 super 5G network. Although the wireless devices 100a to 100f may communicate with each other via the BS 200 / network 300, the wireless devices 100a to 100f may perform direct communication (e.g., sidelink communication) with each other without passing through the BS 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). An IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0044] Wireless communication / connection 150a, 150b, and 150c may be established between wireless devices 100a to 100f and / or between wireless devices 100a to 100f and BS 200 and / or between BS 200. In this document, wireless communication / connection 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. Wireless devices 100a to 100f and BS 200 / wireless devices 100a to 100f may send / receive radio signals to each other through wireless communication / connection 150a, 150b, and 150c. For example, wireless communication / connection 150a, 150b, and 150c may send / receive signals through various physical channels. To this end, various configuration information configuration processes for sending / receiving radio signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, and resource mapping / demapping), and at least a portion of the resource allocation process may be performed based on various proposals of the present disclosure.

[0045] NR supports multiple parameter sets (and / or multiple subcarrier spacing (SCS)) to support various 5G services. For example, if the SCS is 15kHz, wide areas can be supported in traditional cellular bands, and if the SCS is 30kHz / 60kHz, dense cities, lower latency, and wider carrier bandwidths can be supported. If the SCS is 60kHz or higher, bandwidths greater than 24.25GHz can be supported to overcome phase noise.

[0046] The NR frequency band may be defined as two types of frequency ranges, namely, frequency range 1 (FR1) and frequency range 2 (FR2). The numerical values ​​of the frequency ranges may be changed. For example, the two types of frequency ranges (FR1 and FR2) may be as shown in Table 1 below. For ease of explanation, in the frequency range used in the NR system, FR1 may mean "a range below 6 GHz", FR2 may mean "a range above 6 GHz", and may be referred to as millimeter wave (mmW).

[0047] [Table 1]

[0048] Frequency range specification Corresponding frequency range Subcarrier spacing FR1 450MHz–6000MHz 15, 30, 60kHz FR2 24250MHz–52600MHz 60, 120, 240kHz

[0049] As mentioned above, the value of the frequency range of the NR system can be changed. For example, FR1 may include 410 MHz to 7125 MHz as shown in Table 2 below. That is, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or above. For example, the frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or above included in FR1 may include an unlicensed frequency band. The unlicensed frequency band can be used for various purposes, for example, communication of vehicles (e.g., autonomous driving).

[0050] [Table 2]

[0051] Frequency range specification Corresponding frequency range Subcarrier spacing FR1 410MHz–7125MHz 15, 30, 60kHz FR2 24250MHz–52600MHz 60, 120, 240kHz

[0052] Here, the radio communication technology implemented in the wireless device 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 a low-power wide area network (LPWAN) technology, which may be implemented in specifications such as LTE Cat NB1 and / or LTE Cat NB2, and may not be limited to the names mentioned above. Additionally and / or alternatively, the radio communication technology implemented in the wireless device in the present disclosure may be based on LTE-M technology for communication. For example, LTE-M technology may be an example of LPWAN technology and is referred to as various names such as enhanced MTC (eMTC). For example, LTE-M technology may be implemented in at least one of 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 names. Additionally and / or alternatively, the radio communication technology implemented in the wireless device in the present disclosure may include at least one of ZigBee, Bluetooth, and / or LPWAN considering low-power communication, and may not be limited to the names mentioned above. For example, ZigBee technology may generate a personal area network (PAN) associated with small / low-power digital communication based on various specifications such as IEEE 802.15.4, and may be referred to as various names.

[0053] Figure 2 An example of a wireless device to which an embodiment of the present disclosure is applied is shown.

[0054] exist Figure 2 In the embodiment, the first wireless device 100 and / or the second wireless device 200 may be implemented in various forms according to the usage / service. For example, {the first wireless device 100 and the second wireless device 200} may correspond to Figure 1 At least one of {wireless devices 100a to 100f and BS200}, {wireless devices 100a to 100f and wireless devices 100a to 100f} and / or {BS200 and BS200}. The first wireless device 100 and / or the second wireless device 200 may be configured by various elements, devices / components and / or modules.

[0055] The first wireless device 100 may include at least one transceiver, such as the transceiver 106 ; at least one processing chip, such as the processing chip 101 ; and / or one or more antennas 108 .

[0056] The processing chip 101 may include at least one processor, such as the processor 102, and at least one memory, such as the memory 104. Additionally and / or alternatively, the memory 104 may be placed outside the processing chip 101.

[0057] The processor 102 may control the memory 104 and / or the transceiver 106 and may be adapted to implement the descriptions, functions, processes, suggestions, methods and / or operational flow charts described in the present disclosure. For example, the processor 102 may process the information in the memory 104 to generate a first information / signal, and then transmit a radio signal including the first information / signal through the transceiver 106. The processor 102 may receive a radio signal including a second information / signal through the transceiver 106 and then store information obtained by processing the second information / signal in the memory 104.

[0058] The memory 104 may be operably connected to the processor 102. The memory 104 may store various types of information and / or instructions. The memory 104 may store firmware and / or software code 105 that implements codes, commands, and / or sets of commands that, when executed by the processor 102, perform the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure. For example, the firmware and / or software code 105 may implement instructions that, when executed by the processor 102, perform the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure. For example, the firmware and / or software code 105 may control the processor 102 to execute one or more protocols. For example, the firmware and / or software code 105 may control the processor 102 to execute one or more layers of a radio interface protocol.

[0059] In this document, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement a 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 transceivers 106 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with a radio frequency (RF) unit. In the present disclosure, the first wireless device 100 may represent a communication modem / circuit / chip.

[0060] The second wireless device 200 may include at least one transceiver, such as the transceiver 206 ; at least one processing chip, such as the processing chip 201 ; and / or one or more antennas 208 .

[0061] The processing chip 201 may include at least one processor, such as the processor 202, and at least one memory, such as the memory 204. Additionally and / or alternatively, the memory 204 may be placed outside the processing chip 201.

[0062] The processor 202 may control the memory 204 and / or the transceiver 206 and may be adapted to implement the descriptions, functions, processes, suggestions, methods and / or operational flow charts described in the present disclosure. For example, the processor 202 may process the information in the memory 204 to generate third information / signals, and then transmit a radio signal including the third information / signals through the transceiver 206. The processor 202 may receive a radio signal including fourth information / signals through the transceiver 106, and then store information obtained by processing the fourth information / signals in the memory 204.

[0063] The memory 204 may be operably connected to the processor 202. The memory 204 may store various types of information and / or instructions. The memory 204 may store firmware and / or software code 205 that implements codes, commands, and / or sets of commands that, when executed by the processor 202, perform the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure. For example, the firmware and / or software code 205 may implement instructions that, when executed by the processor 202, perform the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure. For example, the firmware and / or software code 205 may control the processor 202 to execute one or more protocols. For example, the firmware and / or software code 205 may control the processor 202 to execute one or more layers of a radio interface protocol.

[0064] In this document, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement a 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 transceivers 206 may include a transmitter and / or a receiver. The transceiver 206 may be used interchangeably with an RF unit. In the present disclosure, the second wireless device 200 may represent a communication modem / circuit / chip.

[0065] Hereinafter, the hardware elements of the wireless devices 100 and 200 will be described in more detail. One or more protocol layers may be implemented by, but not limited to, one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as physical (PHY), layer, medium 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). One or more processors 102 and 202 may generate one or more protocol data units (PDUs), one or more service data units (SDUs), messages, control information, data, or information according to the descriptions, functions, processes, suggestions, methods, and / or operation flow charts disclosed in the present disclosure. The one or more processors 102 and 202 may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the description, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure and provide the generated signal to the one or more transceivers 106 and 206. The one or more processors 102 and 202 may receive a signal (e.g., a baseband signal) from the one or more transceivers 106 and 206 and obtain the PDU, SDU, message, control information, data, or information according to the description, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure.

[0066] One or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. 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 one or more processors 102 and 202. For example, one or more processors 102 and 202 may be configured by a collection of a communication control processor, an application processor (AP), an electronic control unit (ECU), a central processing unit (CPU), a graphics processing unit (GPU), and a memory control processor. One or more memories 104 and 204 may be connected to one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, codes, instructions, and / or commands.

[0067] 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 and non-volatile memory, hard disk drive, register, cache memory, computer-readable storage medium and / or a combination thereof. The one or more memories 104 and 204 may be located inside and / or outside 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 connections.

[0068] One or more transceivers 106 and 206 may send user data, control information, and / or radio signals / channels mentioned in the description, function, process, suggestion, method, and / or operation flow chart disclosed in the present disclosure to one or more other devices. One or more transceivers 106 and 206 may receive user data, control information, and / or radio signals / channels mentioned in the description, function, process, suggestion, method, and / or operation flow chart disclosed in the present disclosure from one or more other devices. For example, one or more transceivers 106 and 206 may be connected to one or more processors 102 and 202 and send and receive radio signals. For example, one or more processors 102 and 202 may perform control so that one or more transceivers 106 and 206 may send user data, control information, or radio signals to one or more other devices. One or more processors 102 and 202 may perform control so that one or more transceivers 106 and 206 may receive user data, control information, or radio signals from one or more other devices.

[0069] One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208. Additionally and / or alternatively, one or more transceivers 106 and 206 may include one or more antennas 108 and 208. 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, processes, suggestions, methods, and / or operational flow charts disclosed in the present disclosure. In the present disclosure, one or more antennas 108 and 208 may be multiple physical antennas or multiple logical antennas (e.g., antenna ports).

[0070] The one or more transceivers 106 and 206 may convert the received user data, control information, radio signals / channels, etc. from RF band signals to baseband signals so as to process the 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 baseband signals to 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 may up-convert OFDM baseband signals to OFDM signals through 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 an OFDM signal at a carrier frequency and down-convert the OFDM signal to an OFDM baseband signal through their (analog) oscillators and / or filters under the control of the one or more processors 102 and 202 .

[0071] Although in Figure 2 140, but the wireless devices 100 and 200 may further include additional components. The additional components 140 may be configured differently depending on the type 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., an audio I / O port, a video I / O port), a drive 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 wired or wireless connections.

[0072] In an embodiment of the present disclosure, a UE may operate as a transmitting device in UL and as a receiving device in DL. In an embodiment of the present disclosure, a BS may operate as a receiving device in UL and as a transmitting device in DL. In the following, for the convenience of description, it is mainly assumed that the first wireless device 100 is a UE and the second wireless device 200 is a BS. For example, the processor 102 connected to, installed on, or started in the first wireless device 100 may be suitable for executing the UE behavior according to the embodiment of the present disclosure or controlling the transceiver 106 to execute the UE behavior according to the embodiment of the present disclosure. The processor 202 connected to, installed on, or started in the second wireless device 200 may be suitable for executing the BS behavior according to the embodiment of the present disclosure or controlling the transceiver 206 to execute the BS behavior according to the embodiment of the present disclosure.

[0073] In this disclosure, a BS is also referred to as a Node B (NB), an eNode B (eNB), or a gNB.

[0074] Figure 3 An example of a UE to which an embodiment of the present disclosure is applied is shown.

[0075] refer to Figure 3 , UE 100 may correspond to Figure 2 A first wireless device 100 is provided.

[0076] 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 identity module (SIM) card 145 , a speaker 146 , and a microphone 147 .

[0077] The processor 102 may be configured to implement the descriptions, functions, processes, suggestions, methods and / or operational flow charts disclosed in the present disclosure. The processor 102 may be configured to control one or more other components of the UE 100 to implement the descriptions, functions, processes, suggestions, methods and / or operational flow charts disclosed in the present disclosure. The layers of the radio interface protocol may be implemented in the processor 102. The processor 102 may include an ASIC, other chipsets, logic circuits and / or data processing devices. The processor 102 may be an application processor. The processor 102 may include at least one of a DSP, a CPU, a GPU, a modem (modulator and demodulator). Examples of the processor 102 may be found in MANUFACTURED BY SNAPDRAGON TM Series processors, Manufactured by EXYNOS TM Series processors, A series processors manufactured by Made by HELIO TM Series processors, ATOM manufactured TM series processors or the corresponding next-generation processors.

[0078] The memory 104 is operably connected to the processor 102 and stores various information to operate the processor 102. The memory 104 may include ROM, RAM, flash memory, memory card, storage medium and / or other storage devices. When the embodiment is implemented in software, the technology described herein can be implemented with modules (e.g., processes, functions, etc.) that execute the descriptions, functions, processes, suggestions, methods and / or operational flow charts disclosed in this 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 outside the processor 102, in which case the memory 104 can be communicatively connected to the processor 102 via various means known in the art.

[0079] The transceiver 106 is operably connected to the processor 102 and transmits and / or receives radio signals. The transceiver 106 includes a transmitter and a receiver. The transceiver 106 may include a baseband circuit for processing radio frequency signals. The transceiver 106 controls one or more antennas 108 to transmit and / or receive radio signals.

[0080] The power management module 141 manages the power of the processor 102 and / or the transceiver 106. The battery 142 supplies power to the power management module 141.

[0081] The display 143 outputs the result processed by the processor 102. The keyboard 144 receives input to be used by the processor 102. The keyboard 144 may be shown on the display 143.

[0082] The SIM card 145 is an integrated circuit designed to securely store an International Mobile Subscriber Identity (IMSI) number and its associated keys, which are used to identify and authenticate subscribers on mobile telephony devices such as mobile phones and computers. Contact information can also be stored on many SIM cards.

[0083] The speaker 146 outputs sound related results processed by the processor 102. The microphone 147 receives sound related input to be used by the processor 102.

[0084] Figure 4 and Figure 5 An example of a protocol stack in a 3GPP-based wireless communication system to which implementations of the present disclosure are applied is shown.

[0085] Specifically, Figure 4 An example of a radio interface user plane protocol stack between a UE and a BS is illustrated, and Figure 5An example of a radio interface control plane protocol stack between a UE and a BS is illustrated. The control plane refers to a path through which control messages for managing calls made between a UE and a network are transmitted. The user plane refers to a path through which data generated in an application layer (e.g., voice data or Internet packet data) is transmitted. Figure 4 , the user plane protocol stack can be divided into layer 1 (ie, PHY layer) and layer 2. Figure 5 , the control plane protocol stack can be divided into layer 1 (ie, PHY layer), layer 2, layer 3 (eg, RRC layer), and non-access stratum (NAS) layer. Layer 1, layer 2, and layer 3 are called access stratum (AS).

[0086] In the 3GPP LTE system, Layer 2 is separated into the following sublayers: MAC, RLC, and PDCP. In the 3GPP NR system, Layer 2 is separated into the following sublayers: MAC, RLC, PDCP, and SDAP. The PHY layer provides transport channels to the MAC sublayer, the MAC sublayer provides logical channels to the RLC sublayer, the RLC sublayer provides RLC channels to the PDCP sublayer, and the PDCP sublayer provides radio bearers to the SDAP sublayer. The SDAP sublayer provides Quality of Service (QoS) flows to the 5G core network.

[0087] In the 3GPP NR system, the main services and functions of the MAC sublayer include: mapping between logical channels and transport channels; multiplexing / demultiplexing MAC SDUs belonging to one or different logical channels to / from transport blocks (TBs) on transport channels for delivery to / from the physical layer; scheduling information reporting; error correction through hybrid automatic repeat request (HARQ) (one HARQ entity per cell in the case of carrier aggregation (CA); priority handling between UEs through dynamic scheduling; priority handling between logical channels of one UE through logical channel prioritization; padding. A single MAC entity can support multiple parameter sets, transmission timings, and cells. The mapping restrictions in the logical channel prioritization control which parameter set(s), cell, and transmission timing can be used by the logical channel.

[0088] MAC provides different kinds of data transmission services. In order to accommodate different kinds of data transmission services, multiple types of logical channels are defined, that is, each logical channel supports the transmission of a specific type of information. Each logical channel type is defined by what type of information is transmitted. Logical channels are divided into two groups: control channels and traffic channels. Control channels are used only for the transmission of control plane information, and traffic channels are used only for the transmission of user plane information. The broadcast control channel (BCCH) is a downlink logical channel for broadcasting system control information, the paging control channel (PCCH) is a downlink logical channel for transmitting paging information, system information change notifications, and indications of ongoing public warning services (PWS) broadcasts, the common control channel (CCCH) is a logical channel used to send control information between the UE and the network and is used by UEs that do not have an RRC connection with the network, and the dedicated control channel (DCCH) is a point-to-point bidirectional logical channel used by UEs with RRC connections to send dedicated control information between the UE and the network. The dedicated traffic channel (DTCH) is a point-to-point logical channel dedicated to one UE for transmitting user information. DTCH can exist in both the uplink and downlink. In the downlink, there are the following connections between logical channels and transport channels: BCCH can be mapped to the broadcast channel (BCH); BCCH can be mapped to the downlink shared channel (DL-SCH); PCCH can be mapped to the 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 the uplink, there are the following connections between logical channels and transport channels: CCCH can be mapped to the uplink shared channel (UL-SCH); DCCH can be mapped to UL-SCH; and DTCH can be mapped to UL-SCH.

[0089] The RLC sublayer supports three transmission modes: transparent mode (TM), unacknowledged mode (UM) and acknowledged mode (AM). The RLC configuration is per logical channel without dependency on parameter sets and / or transmission duration. In 3GPP NR systems, the main services and functions of the RLC sublayer depend on the transmission mode and include: delivery of upper layer PDUs; sequence numbering independent of sequence numbering 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 SDUs (AM and UM); duplicate detection (AM only); RLC SDU discard (AM and UM); RLC reconstruction; protocol error detection (AM).

[0090] 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); transmission of user data; reordering and duplicate detection; in-sequence delivery; PDCP PDU routing (in the case of split bearers); retransmission of PDCP SDU; ciphering, deciphering and integrity protection; PDCP SDU discard; PDCP reestablishment and data recovery for RLC AM; PDCP status reporting for RLC AM; duplication of PDCP PDU 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; transmission of control plane data; reordering and duplicate detection; in-sequence delivery; duplication of PDCP PDU and duplicate discard indication to lower layers.

[0091] In 3GPP NR system, the main services and functions of SDAP include: mapping between QoS flows and data radio bearers; marking QoS flow ID (QFI) in both DL and UL packets. A single protocol entity of SDAP is configured for each individual PDU session.

[0092] 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 the 5G core network (5GC) or the next generation radio access network (NG-RAN); establishment, maintenance and release of the RRC connection between the UE and the 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 reporting; detection and recovery of radio link failure; NAS message transmission from UE to NAS / from NAS to UE.

[0093] Figure 6 A frame structure in a 3GPP-based wireless communication system to which the present disclosure is applied is shown.

[0094] Figure 6The frame structure shown in is merely exemplary, and the number of subframes, the number of time slots, and / or the number of symbols in a frame may vary. In a 3GPP-based wireless communication system, OFDM parameter sets (e.g., SCS, transmission time interval (TTI) duration) may be configured differently between multiple cells aggregated for one UE. For example, if the UE is configured with different SCSs for cells aggregated for the cell, the (absolute time) duration of time resources (e.g., subframes, time slots, or TTIs) including the same number of symbols may be different among the aggregated cells. In this article, the symbol may include an OFDM symbol (or a cyclic prefix (CP)-OFDM symbol), an SC-FDMA symbol (or a discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbol).

[0095] Reference Figure 6 , downlink and uplink transmissions are organized into frames. Each frame has T f = 10ms duration. Each frame is divided into two half-frames, where each half-frame has a duration of 5ms. Each half-frame includes 5 sub-frames, where the duration of each sub-frame is T sf is 1ms. Each subframe is divided into slots, and the number of slots in a subframe depends on the subcarrier spacing. Each slot includes 14 or 12 OFDM symbols based on the CP. In a normal CP, each slot includes 14 OFDM symbols, and in an extended CP, each slot includes 12 OFDM symbols. The parameter set is based on an exponentially scalable subcarrier spacing Af=2 u *15kHz.

[0096] Table 3 shows the subcarrier spacing Af=2 u *N is the number of OFDM symbols per time slot of 15kHz slot symb , the number of time slots per frame N frame，u slot , and the number of time slots N per subframe for normal CP subframme，u slot .

[0097] [Table 3]

[0098] u <![CDATA[N slot symb ]]> <![CDATA[N frame，u slot ]]> <![CDATA[N subframe，u slot <!-- 10 -->]]> 0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16

[0099] Table 4 shows the subcarrier spacing Δf=2 u *N is the number of OFDM symbols per time slot of 15kHz slot symb , the number of time slots per frame N frame，u slot and the number of slots N per subframe for the extended CPsubframe，u slot .

[0100] [Table 4]

[0101] u <![CDATA[N slot symb ]]> <![CDATA[N frame，u slot ]]> <![CDATA[N subframe，u slot ]]> 2 12 40 4

[0102] A slot includes a plurality of symbols (e.g., 14 or 12 symbols) in the time domain. For each parameter set (e.g., subcarrier spacing) and carrier, a common resource block (CRB) N indicated by higher layer signaling (e.g., RRC signaling) is allocated. start，u grid To begin, we define N size，u grid，x *N RB sc subcarriers and N subframe，u symb OFDM symbol resource grid, where N size，u grid，x is the number of resource blocks (RBs) in the resource grid, and the subscript x is DL for the downlink and UL for the uplink. N RB sc is the number of subcarriers per RB. In 3GPP-based wireless communication systems, N RB sc Typically 12. For a given antenna port p, subcarrier spacing configuration u, and transmission direction (DL or UL), there is one resource grid. The carrier bandwidth N for subcarrier spacing configuration u size，u grid Given by high-level parameters (e.g., RRC parameters). Each element in the resource grid for antenna port p and subcarrier spacing configuration u is called a resource element (RE), and one complex symbol can be mapped to each RE. Each RE in the resource grid is uniquely identified by an index k in the frequency domain and an index l representing the symbol position relative to a reference point in the time domain.

[0103] In 3GPP-based wireless communication systems, an RB is defined by 12 consecutive subcarriers in the frequency domain. In 3GPP NR systems, RBs are classified into CRBs and physical resource blocks (PRBs). CRBs are numbered upwards from 0 in the frequency domain for subcarrier spacing configuration u. The center of subcarrier 0 of CRB 0 for subcarrier spacing configuration u coincides with "point A" used as a common reference point for the resource block grid. In 3GPP NR systems, PRBs are defined within bandwidth parts (BWPs) and are numbered from 0 to N. size BWP，i -1 numbering, where i is the number of the bandwidth part. Physical resource block n in bandwidth part i PRB With common resource block n CRB The relationship between is as follows:PRB =n CRB +N size BWP，i , where N size BWP，i It is a common resource block where the bandwidth part starts relative to CRB 0. A BWP includes multiple consecutive RBs. A carrier can include up to N (e.g., 5) BWPs. A UE can be configured with one or more BWPs on a given component carrier. Only one BWP can be activated at a time among the BWPs configured for a UE. The active BWP defines the operating bandwidth of the UE within the operating bandwidth of the cell.

[0104] In the present disclosure, the term "cell" may refer to a geographical area where one or more nodes provide a communication system or to a radio resource. "Cell" as a geographical area can be understood as a coverage range in which a node can provide services using a carrier, and "cell" as a radio resource (e.g., time-frequency resource) is associated with a bandwidth, which is a frequency range configured by a carrier. A "cell" associated with a radio resource is defined by a combination of downlink resources and uplink resources (e.g., a combination of DL component carriers (CCs) and UL CCs). A cell may be configured only by downlink resources, or may be configured by downlink resources and uplink resources. Since the DL coverage (which is the range in which a node can send a valid signal) and the UL coverage (which is the range in which a node can receive a valid signal from a UE) depend on the carrier carrying the signal, the coverage of a node may be associated with the coverage of a "cell" of a radio resource used by the node. Therefore, the term "cell" may be used to sometimes represent the service coverage of a node, to represent a radio resource at other times, or to represent a range in which a signal using a radio resource can reach with effective strength at other times.

[0105] In CA, two or more CCs are aggregated. The UE can receive or transmit on one or more CCs simultaneously according to its capabilities. CA is supported for both continuous CCs and non-contiguous CCs. When CA is configured, the UE has only one RRC connection with the network. During RRC connection establishment / reconstruction / switching, one serving cell provides NAS mobility information, and during RRC connection reconstruction / switching, one serving cell provides security input. This cell is called the primary cell (PCell). PCell is a cell operating on the primary frequency, where the UE performs an initial connection establishment process or initiates a connection reconstruction process. Depending on the UE capabilities, a secondary cell (SCell) can be configured to form a set of serving cells together with the PCell. SCell is a cell that provides additional radio resources on top of a special cell (PCell). Therefore, the set of configured serving cells for the UE always consists of one PCell and one or more SCells. For dual connection (DC) operation, the term "PCell" refers to the PCell of the primary cell group (MCG) or the primary SCell (PSCell) of the secondary cell group (SCG). SpCell supports physical uplink control channel (PUCCH) transmission and contention-based random access, and is always activated. MCG is a set of serving cells associated with the master node, which includes SpCell (PCell) and optionally one or more SCells. For UEs configured with DC, SCG is a subset of serving cells associated with the secondary node, which includes PSCell and zero or more SCells. For UEs in RRC_CONNECTED that are not configured with CA / DC, there is only one serving cell consisting of PCell. For UEs in RRC_CONNECTED that are configured with CA / DC, the term "serving cell" is used to refer to the set of cells consisting of SpCell and all SCells. In DC, two MAC entities are configured in the UE: one for MCG and one for SCG.

[0106] Figure 7 An example of data flow in a 3GPP NR system to which implementations of the present disclosure are applied is shown.

[0107] Reference Figure 7 , "RB" means radio bearer, and "H" means header. Radio bearers are classified into two groups: DRB for user plane data and SRB for control plane data. MAC PDU is transmitted / received to / from an external device through the PHY layer using radio resources. MAC PDU arrives at the PHY layer in the form of a transport block.

[0108] In the PHY layer, the uplink transport channel UL-SCH and the random access channel (RACH) are mapped to their physical channels, the physical uplink shared channel (PUSCH) and the physical random access channel (PRACH), respectively, and the downlink transport channels DL-SCH, BCH and PCH are mapped to the physical downlink shared channel (PDSCH), the physical broadcast channel (PBCH) and the PDSCH, respectively. In the PHY layer, the uplink control information (UCI) is mapped to the physical PUCCH, and the downlink control information (DCI) is mapped to the physical downlink control channel (PDCCH). The MAC PDU related to the UL-SCH is sent by the UE via the PUSCH based on the UL grant, and the MAC PDU related to the DL-SCH is sent by the BS via the PDSCH based on the DL assignment.

[0109] Network-controlled mobility is applicable to UEs under RRC_CONNECTED and is classified into two types of mobility: cell-level mobility and beam-level mobility. Beam-level mobility includes intra-cell beam-level mobility and inter-cell beam-level mobility.

[0110] Cell-level mobility requires triggering explicit RRC signaling, i.e. handover. For inter-gNB handover, the signaling process consists of at least the following operations.

[0111] 1. The source gNB initiates a handover and sends a HANDOVER REQUEST message through the Xn interface.

[0112] 2. The target gNB performs admission control and provides the new RRC configuration as part of the HANDOVER REQUESTACKNOWLEDGE message.

[0113] 3. The source gNB provides the RRC configuration to the UE by forwarding the RRCReconfiguration message received in the HANDOVER REQUEST ACKNOWLEDGE message. The RRCReconfiguration message includes at least the cell identity (ID) and all information required to access the target cell so that the UE can access the target cell without reading system information. For some cases, the information required for contention-based and contention-free random access may be included in the RRCReconfiguration message. The access information for the target cell may include beam-specific information (if any).

[0114] 4. The UE moves the RRC connection to the target gNB and replies with an RRCReconfigurationComplete message.

[0115] In case of Dual Active Protocol Stack (DAPS) handover, the UE continues DL user data reception from the source gNB until the source cell is released and continues UL user data transmission to the source gNB until the random access procedure to the target gNB is successful.

[0116] During DAPS handover, only the source PCell and the target PCell are used. CA, DC, Supplementary UL (SUL), Multiple Transmit / Receive Points (TRP), Ethernet Header Compression (EHC), Conditional Handover (CHO), User Data Convergence (UDC), NR side link configuration and V2X side link configuration are released by the source gNB before the Handover Command is sent to the UE and are not configured by the target gNB until the DAPS handover is completed (i.e., at the earliest in the same message that releases the source PCell).

[0117] The handover mechanisms triggered by RRC require the UE to at least reset the MAC entity and re-establish the RLC, except for DAPS handover, where upon receiving the handover command, the UE:

[0118] -Create a MAC entity for the target;

[0119] - For each DRB configured with DAPS, establish a targeted RLC entity and associated DTCH logical channel;

[0120] - For each DRB configured with DAPS, reconfigure the PDCP entities with separate security and ROHC functions for the source and target, and associate these PDCP entities with the RLC entities configured by the source and target respectively;

[0121] - Keep the rest of the source configuration until the source is released.

[0122] RRC managed handover with and without PDCP entity re-establishment is supported. For DRBs using RLC AM mode, PDCP can re-establish with a security key change or initiate a data recovery procedure without a key change. For DRBs using RLC UM mode, PDCP can re-establish with a security key change or remain intact without a key change. For SRBs, PDCP can remain intact, discard its stored PDCP PDU / SDU without a key change, or re-establish with a security key change.

[0123] When the target gNB uses the same DRB configuration as the source gNB, data forwarding, in-sequence delivery, and duplication avoidance at handover can be guaranteed.

[0124] A timer-based handover failure procedure is supported in NR. The RRC connection reestablishment procedure is used to recover from a handover failure, except in certain CHO or DAPS handover scenarios:

[0125] - When DAPS handover fails, the UE falls back to the source cell configuration, resumes the connection with the source cell, and if the source link has not been released, reports the DAPS handover failure via the source without triggering RRC connection re-establishment.

[0126] - When the initial CHO execution attempt fails or HO fails, the UE performs cell selection, and if the selected cell is a CHO candidate and if the network configures the UE to attempt CHO after handover / CHO failure, the UE attempts CHO execution once, otherwise performs re-establishment.

[0127] Beam level mobility does not require triggering explicit RRC signaling. Beam level mobility can be intra-cell or inter-cell, the latter being referred to as inter-cell beam management (ICBM). For ICBM, the UE can receive or send UE-specific channels / signals via a TRP associated with a physical cell ID (PCI) different from the serving cell's PCI, while non-UE-specific channels / signals can only be received via a TRP associated with the serving cell's PCI. The gNB provides the UE with a measurement configuration via RRC signaling, which contains synchronization signal block (SSB) / channel state information (CSI) resources and resource sets, reports, and configuration of trigger states for triggering channel and interference measurements and reports. In the case of ICBM, the measurement configuration includes SSB resources associated with a PCI different from the serving cell's PCI. Beam level mobility is then handled at a low level with the help of physical layer and MAC layer control signaling, and RRC is not required to know which beam is being used at a given point in time.

[0128] SSB-based beam-level mobility is based on the SSB associated with the initial DL BWP and can only be configured for the initial DL BWP and the DL BWP containing the SSB associated with the initial DL BWP. For other DL BWPs, beam-level mobility can only be performed based on CSI-RS.

[0129] CHO is defined as a handover performed by the UE when one or more handover execution conditions are met. The UE starts evaluating the execution conditions when receiving the CHO configuration and stops evaluating the execution conditions once the handover is performed.

[0130] The following principles apply to CHO:

[0131] -CHO configuration contains the configuration of CHO candidate cells generated by the candidate gNB and the execution conditions generated by the source gNB.

[0132] - The execution condition can consist of one or two trigger conditions (CHO events A3 / A5). Only a single reference signal (RS) type is supported, and up to two different trigger quantities (e.g., reference signal received power (RSRP) and reference signal received quality (RSRQ), RSRP to noise plus interference ratio (SINR), etc.) can be configured simultaneously for the evaluation of the CHO execution condition of a single candidate cell.

[0133] - Before any CHO execution conditions are met, upon receiving a HO command (without CHO configuration), the UE performs the HO procedure regardless of any previously received CHO configuration.

[0134] - While performing CHO, ie from the time the UE starts synchronizing with the target cell, the UE does not monitor the source cell.

[0135] In 3GPP Release 18, inter-cell mobility based on L1 / L2 commands may be introduced to reduce latency, overhead, and interruption time. Inter-cell mobility based on L1 / L2 commands may be referred to as low layer triggered mobility (LTM) and / or may be simply referred to as L1 / L2 mobility.

[0136] For L1 / L2 mobility, the network may provide the UE with the configuration of the candidate serving cell in advance. If the UE receives the corresponding mobility command via L1 / L2 signaling, the UE may apply the configuration of the candidate serving cell indicated by the L1 / L2 signaling. In order to shorten the latency and interruption time caused by inter-cell mobility from the serving cell to the candidate serving cell, the UE may be pre-configured with a candidate serving cell. For example, the UE may pre-receive an RRCReconfiguration including reconfigurationWithSync. Then, the UE may perform the following operations for the candidate serving cell:

[0137] - Timing Advance (TA) maintenance: To obtain the TA, the UE may perform random access to a candidate serving cell upon receiving the configuration of the candidate serving cell.

[0138] -Radio Link Monitoring (RLM)

[0139] -Beam Failure Detection (BFD)

[0140] -Radio Resource Management (RRM) measurements

[0141] In existing inter-cell mobility (e.g., network-controlled mobility and conditional mobility), when mobility is successfully completed, upon receiving an explicit release from the target node, the UE can release the resources and configuration of the source cell and stop DL / UL reception / transmission with the source cell. In addition, the UE can stop maintaining the TA for the source cell.

[0142] After a successful mobility execution, the UE may receive a mobility command indicating a handover toward the previous serving cell. The UE shall then perform a random access procedure on the previous serving cell, since the UE does not perform TA maintenance and RLM on the previous serving cell. In other words, if another mobility is to be performed on the previous serving cell, the network shall re-provision the configuration of the previous serving cell, and the UE shall perform a random access procedure on the previous serving cell to regain the TA. Based on conventional principles, the previous serving cell may be added as a candidate serving cell after a successful mobility execution to prepare for continuous mobility. However, in this case, upon receiving the corresponding configuration, the UE shall initiate time-consuming operations, such as a random access procedure, to the configured candidate serving cell. These may result in long delays and interruption times.

[0143] If the UE keeps maintaining the configuration of the TA and the previous serving cell, the previous serving cell will be a good candidate serving cell, especially in the dynamic switching scenario between candidate serving cells. Using dynamic switching of candidate serving cells will be useful even when the serving cell quality has not deteriorated, for example, in cell on / off scenarios for network energy saving or for load balancing between candidate serving cells. In such scenarios, switching to the previous serving cell will occur frequently, and it is beneficial for the UE to keep the previous serving cell as a candidate serving cell after a successful mobility execution.

[0144] Therefore, a method for handling a previous serving cell using a candidate serving cell after inter-cell mobility may be needed. Specifically, a method for keeping a previous serving cell as a new candidate serving cell after L1 / L2 mobility based on a candidate cell may be needed.

[0145] According to an implementation of the present disclosure, when the serving cell changes, the UE may maintain the configuration and / or resources of the source cell, and may change the state of the source cell to a candidate serving cell. That is, after the serving cell changes (i.e., after a successful mobility execution), the UE may include the source cell in a list of candidate serving cells that the UE has maintained for mobility events. Thus, the configuration of the source cell may be transferred to the list of candidate serving cell configurations, i.e., the configuration of the source cell may be maintained / retained even after a successful mobility execution.

[0146] According to an implementation of the present disclosure, the UE may maintain the configuration and / or resources of the source cell based on an indication provided by the network, and may change the state of the source cell to a candidate serving cell. In other words, if the mobility command includes an indication indicating that the source cell is changed to a candidate serving cell after successful mobility execution, the UE may maintain the configuration and / or resources of the source cell, and may change the state of the source cell to a candidate serving cell.

[0147] According to an implementation of the present disclosure, for the signaling of the indication, the indication may be included in a mobility command. Alternatively and / or additionally, the indication may be preconfigured as part of the serving cell configuration. That is, the indication may be preconfigured per serving cell. When multiple serving cells are configured, an indication may be provided in each of the multiple serving cell configurations. Alternatively and / or additionally, the indication may be preconfigured as a pair of a target cell and a source cell. In this case, the source cell configuration may be retained only when mobility causes the serving cell to change from the source cell to the corresponding target cell. Alternatively and / or additionally, an indication may be provided in a conditional mobility configuration.

[0148] If the serving cell configuration is retained after mobility, the UE may maintain the operations performed in the previous serving cell in the candidate serving cell during or after mobility. For example, the UE may continue to perform TA maintenance operations and / or BFD / RLF operations for the candidate serving cell (i.e., the previous serving cell).

[0149] The following figures are created to explain specific embodiments of the present disclosure. The names of specific devices or names of specific signals / messages / fields shown in the figures are provided by way of example, so the technical features of the present disclosure are not limited to the specific names used in the following figures.

[0150] Figure 8 An example of a method performed by a wireless device to which an implementation of the present disclosure is applied is shown.

[0151] In step S800 , the method includes receiving a cell configuration for a first cell.

[0152] In step S810, the method includes receiving a candidate cell configuration for a second cell. The second cell is added to a candidate cell list for mobility.

[0153] In step S820, the method includes applying the candidate cell configuration for the second cell upon receiving the first mobility command. That is, the wireless device performs mobility toward the second cell. The first cell is added to a candidate cell list for mobility.

[0154] In some implementations, the first mobility command may be received via any of L1 signaling, L2 signaling, or L3 signaling.

[0155] In some implementations, mobility may include at least one of a network-controlled serving cell change or a UE-autonomous serving cell change (e.g., CHO). That is, the first mobility command may be used for a network-controlled serving cell change or a UE-autonomous serving cell change (e.g., CHO).

[0156] In some implementations, the first mobility command may include target cell information. If the target cell is one of the preconfigured candidate serving cells, the first mobility command may include an identifier (ID) of the candidate serving cell indicated by the first mobility command. Otherwise, if the target cell is not one of the preconfigured candidate serving cells, the first mobility command may include a configuration for the target cell, such as an RRCReconfiguration including reconfigurationWithSync.

[0157] For example, the first mobility command may include a candidate cell configuration for the second cell. That is, the candidate cell configuration for the second cell may be received via the first mobility command. For example, the first mobility command including the candidate cell configuration for the second cell may be an RRCReconfiguration including reconfigurationWithSync.

[0158] For example, based on the fact that the first mobility command does not include a candidate cell configuration for the second cell, the first mobility command may include an identifier of the second cell. That is, if the second cell is one of the preconfigured candidate serving cells, the candidate cell configuration for the second cell may be preconfigured, and the first mobility command may not include the candidate cell configuration for the second cell, but may only include an identifier of the second cell.

[0159] In some implementations, the first mobility command may include a conditional reconfiguration, such as ConditionalReconfiguration.

[0160] In some implementations, explicit information notifying the first cell that it will be added to the candidate list is included in one of the cell configuration or the first mobility command for the first cell. That is, the cell configuration and / or the first mobility command for the first cell may include an indicator indicating that the source cell is changed to a candidate serving cell. For example, the explicit information may be a 1-bit indication in a DCI or MAC control element (CE). For example, the explicit information may be an explicit RRC information element (IE). The target cell may be included in a list, where the list may indicate that the source cell is changed to a candidate serving cell. The cell configuration for the first cell may be retained based on the explicit information.

[0161] In some implementations, the explicit information may be configured per pair of a target cell and a source cell.The source cell may be added to the candidate cell list for mobility based on applying only the candidate cell configuration for the corresponding target cell.

[0162] In some implementations, the first mobility command received via either L1 signaling or L2 signaling may implicitly notify that the first cell will be added to the candidate list. That is, the mobility command received via L1 / L2 signaling may implicitly indicate that the source cell is changed to a candidate serving cell. The cell configuration for the first cell may be retained based on the first mobility command received via either L1 signaling or L2 signaling.

[0163] In some implementations, upon receiving the candidate cell configuration for the second cell, the first cell may be added to the candidate cell list for mobility. Alternatively, upon applying the candidate cell configuration for the second cell, the first cell may be added to the candidate cell list for mobility.

[0164] In some implementations, if the received first mobility command includes ConditionalReconfiguration, and if the execution condition for the second cell is met, the wireless device may apply the stored candidate cell configuration for the second cell (eg, condRRCReconfig).

[0165] In some implementations, if the second cell is one of the pre-configured candidate serving cells, the wireless device may apply the stored candidate cell configuration to the second cell.

[0166] In some implementations, if the second cell is not one of the pre-configured candidate serving cells, the wireless device may apply the candidate cell configuration for the second cell included in the first mobility command.

[0167] In step S830 , the method includes retaining the cell configuration for the first cell.

[0168] In some implementations, the wireless device may send a first message to the second cell when applying the candidate cell configuration for the second cell. The first message may be sent via L1 signaling (e.g., PUCCH, PUSCH, etc.). The first message may be sent via L2 signaling (e.g., MAC CE). The first message may be sent via L3 signaling (e.g., RRCReconfigurationComplete message).

[0169] In some implementations, the wireless device may receive a second message from the second cell in response to the first message. The second message may indicate confirmation of the first message sent to the second cell. The second message may notify that mobility to the second cell is successfully performed.

[0170] In some implementations, while retaining the cell configuration for the first cell, the wireless device may perform at least one of i) TA maintenance, ii) BFD, or iii) RLM for the first cell.

[0171] For example, if the first mobility command message is received via either L1 signaling or L2 signaling and implicitly notifies that the first cell will be added to the candidate list, the wireless device can maintain / retain the cell configuration for the first cell and the resources for the first cell, and can perform at least one of TA maintenance, BFD, and RLM.

[0172] For example, if the first mobility command message includes explicit information notifying that the first cell will be added to the candidate list (i.e., notifying that the source cell is changed to a candidate serving cell), the wireless device can maintain / retain the cell configuration for the first cell and the resources for the first cell, and can perform at least one of TA maintenance, BFD, and RLM.

[0173] In some implementations, otherwise, the wireless device may release the source resources and configuration, and stop DL / UL reception / transmission with the source cell.

[0174] In step S840, the method includes applying the retained cell configuration for the first cell upon receiving the second mobility command.

[0175] In some implementations, the second mobility command may be received via any of L1 signaling, L2 signaling, or L3 signaling.

[0176] In some implementations, a wireless device may communicate with at least one of a mobile device other than the wireless device, a network, and / or an autonomous vehicle.

[0177] In addition, the above Figure 8 The method described in the wireless device perspective can be implemented by Figure 2 The first wireless device 100 and / or Figure 3 The UE 100 shown in FIG.

[0178] The wireless device includes at least one transceiver, at least one processor, and at least one memory capable of being operatively connected to the at least one processor and storing instructions, the instructions being executed based on execution by the at least one processor Figure 8 The method described in .

[0179] More specifically, the wireless device receives a cell configuration for a first cell.

[0180] The wireless device receives a candidate cell configuration for the second cell. The second cell is added to a candidate cell list for mobility.

[0181] Upon receiving the first mobility command, the wireless device applies the candidate cell configuration for the second cell. That is, the wireless device performs mobility toward the second cell. The first cell is added to a candidate cell list for mobility.

[0182] In some implementations, the first mobility command may be received via any of L1 signaling, L2 signaling, or L3 signaling.

[0183] In some implementations, mobility may include at least one of a network-controlled serving cell change or a UE-autonomous serving cell change (e.g., CHO). That is, the first mobility command may be used for a network-controlled serving cell change or a UE-autonomous serving cell change (e.g., CHO).

[0184] In some implementations, the first mobility command may include target cell information. If the target cell is one of the preconfigured candidate serving cells, the first mobility command may include an ID of the candidate serving cell indicated by the first mobility command. Otherwise, if the target cell is not one of the preconfigured candidate serving cells, the first mobility command may include a configuration for the target cell, such as an RRCReconfiguration including reconfigurationWithSync.

[0185] For example, the first mobility command may include a candidate cell configuration for the second cell. That is, the candidate cell configuration for the second cell may be received via the first mobility command. For example, the first mobility command including the candidate cell configuration for the second cell may be an RRCReconfiguration including reconfigurationWithSync.

[0186] For example, based on the fact that the first mobility command does not include a candidate cell configuration for the second cell, the first mobility command may include an identifier of the second cell. That is, if the second cell is one of the preconfigured candidate serving cells, the candidate cell configuration for the second cell may be preconfigured, and the first mobility command may not include the candidate cell configuration for the second cell, but may only include an identifier of the second cell.

[0187] In some implementations, the first mobility command may include a conditional reconfiguration, such as ConditionalReconfiguration.

[0188] In some implementations, explicit information notifying that the first cell will be added to the candidate list is included in one of the cell configuration or the first mobility command for the first cell. That is, the cell configuration and / or the first mobility command for the first cell may include an indicator indicating that the source cell is changed to a candidate serving cell. For example, the explicit information may be a 1-bit indication in a DCI or MAC CE. For example, the explicit information may be an explicit RRC IE. The target cell may be included in a list, where the list may indicate that the source cell is changed to a candidate serving cell. The cell configuration for the first cell may be retained based on the explicit information.

[0189] In some implementations, the explicit information may be configured per pair of a target cell and a source cell.The source cell may be added to the candidate cell list for mobility based on applying only the candidate cell configuration for the corresponding target cell.

[0190] In some implementations, the first mobility command received via either L1 signaling or L2 signaling may implicitly notify that the first cell will be added to the candidate list. That is, the mobility command received via L1 / L2 signaling may implicitly indicate that the source cell is changed to a candidate serving cell. The cell configuration for the first cell may be retained based on the first mobility command received via either L1 signaling or L2 signaling.

[0191] In some implementations, upon receiving the candidate cell configuration for the second cell, the first cell may be added to the candidate cell list for mobility. Alternatively, upon applying the candidate cell configuration for the second cell, the first cell may be added to the candidate cell list for mobility.

[0192] In some implementations, if the received first mobility command includes ConditionalReconfiguration, and if the execution condition is met with respect to the second cell, the wireless device may apply the stored candidate cell configuration for the second cell (eg, condRRCReconfig).

[0193] In some implementations, if the second cell is one of the pre-configured candidate serving cells, the wireless device may apply the stored candidate cell configuration for the second cell.

[0194] In some implementations, if the second cell is not one of the pre-configured candidate serving cells, the wireless device may apply the candidate cell configuration for the second cell included in the first mobility command.

[0195] The wireless device retains the cell configuration for the first cell.

[0196] In some implementations, the wireless device may send a first message to the second cell when applying the candidate cell configuration for the second cell. The first message may be sent via L1 signaling (e.g., PUCCH, PUSCH, etc.). The first message may be sent via L2 signaling (e.g., MAC CE). The first message may be sent via L3 signaling (e.g., RRCReconfigurationComplete message).

[0197] In some implementations, the wireless device may receive a second message from the second cell in response to the first message. The second message may indicate confirmation of the first message sent to the second cell. The second message may notify that mobility to the second cell is successfully performed.

[0198] In some implementations, while retaining the cell configuration for the first cell, the wireless device may perform at least one of i) TA maintenance, ii) BFD, or iii) RLM for the first cell.

[0199] For example, if the first mobility command message is received via either L1 signaling or L2 signaling and implicitly notifies that the first cell will be added to the candidate list, the wireless device can maintain / retain the cell configuration for the first cell and the resources for the first cell, and can perform at least one of TA maintenance, BFD, and RLM.

[0200] For example, if the first mobility command message includes explicit information notifying that the first cell will be added to the candidate list (i.e., notifying that the source cell will be changed to a candidate serving cell), the wireless device can maintain / retain the cell configuration for the first cell and the resources for the first cell, and can perform at least one of TA maintenance, BFD, and RLM.

[0201] In some implementations, otherwise, the wireless device may release the source resources and configuration, and stop DL / UL reception / transmission with the source cell.

[0202] Upon receiving the second mobility command, the wireless device applies the retained cell configuration for the first cell.

[0203] In some implementations, the second mobility command may be received via any of L1 signaling, L2 signaling, or L3 signaling.

[0204] In addition, the above Figure 8 The method described in the wireless device perspective can be controlled by Figure 2 The processor 102 in the first wireless device 100 shown in FIG. 1 and / or by controlling the Figure 3 The process is executed by the processor 102 in the UE 100 shown in FIG.

[0205] A processing device adapted to control a wireless device comprises at least one processor and at least one memory operatively connected to the at least one processor. The at least one processor is adapted to execute Figure 8 The method described in .

[0206] In addition, the above Figure 8 The method described in the wireless device perspective may be performed by storing in a Figure 2 The software code 105 in the memory 104 in the first wireless device 100 shown in FIG. 1 is executed.

[0207] The technical features of the present disclosure may be implemented directly in hardware, in software executed by a processor, or in a combination of the two. For example, the method performed by a wireless device in wireless communication may be implemented in hardware, software, firmware, or any combination thereof. For example, the software may reside in RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disk, removable disk, CD-ROM, or any other storage medium.

[0208] Some examples of storage media may be coupled to a processor so that the processor can read information from the storage media. In an alternative, the storage media may be integrated into the processor. The processor and the storage media may reside in an ASIC. For other examples, the processor and the storage media may reside as discrete components.

[0209] The computer-readable medium may include tangible and non-transitory computer-readable storage media.

[0210] For example, non-transitory computer-readable media may include RAM, such as synchronous DRAM (SDRAM), ROM, non-volatile RAM (NVRAM), EEPROM, flash memory, magnetic or optical data storage media, or any other media that can be used to store instructions or data structures. Non-transitory computer-readable media may also include combinations of the foregoing.

[0211] Furthermore, the methods described herein may be implemented at least in part by a computer-readable communication medium that carries or communicates code in the form of instructions or data structures and can be accessed, read, and / or executed by a computer.

[0212] According to some implementations of the present disclosure, a non-transitory computer readable medium (CRM) stores instructions that are executed based on at least one processor. Figure 8 The method described in .

[0213] In the above description, for example, applying the cell configuration may be performed as follows.

[0214] The UE may perform the following actions upon receiving RRCReconfiguration or upon performing a conditional reconfiguration (CHO, Conditional PSCell Addition (CPA), or Conditional PSCell Change (CPC)).

[0215] 1> If RRCReconfiguration includes masterCellGroup:

[0216] 2>Execute the cell group configuration for the received masterCellGroup;

[0217] 1> If the RRCReconfiguration message includes ConditionalReconfiguration, then:

[0218] 2>Perform conditional reconfiguration;

[0219] For cell group configuration, the UE may perform the following actions based on the received CellGroupConfig IE:

[0220] 1 If CellGroupConfig contains spCellConfig with reconfigurationWithSync:

[0221] 2>Perform reconfiguration with synchronization;

[0222] The UE may perform the following actions to perform reconfiguration with synchronization.

[0223] 1> If AS security is not activated, the action is performed when entering RRC_IDLE, where the release reason is "other", and the process ends;

[0224] 1> If timer T430 is running, stop it;

[0225] 1> According to the target cell NTN-config, start timer T430 from the subframe indicated by epochTime, where the timer value is set to ntn-UlSyncValidityDuration;

[0226] 1> If DAPS bearer is not configured, then:

[0227] 2> If the timer T310 for the corresponding SpCell is running, stop it;

[0228] 1> If the process is executed for MCG:

[0229] 2> If timer T316 is running;

[0230] 3> Stop timer T316;

[0231] 3> Clear the information included in VarRLF-Report (if any);

[0232] 2> If MCG sending is suspended, resume it.

[0233] 1> If the timer T312 for the corresponding SpCell is running, stop it;

[0234] 1> If sl-PathSwitchConfig is included, then:

[0235] 2> Treat the target L2 U2N relay UE as the relay UE indicated by targetRelayUE-Identity in slPathSwitchConfig;

[0236] 2> Start timer T420 for the corresponding target L2 U2N relay UE, where the timer value is set to T420 as included in sl-PathSwitchConfig;

[0237] 2> Apply the value of newUE-Identity as C-RNTI;

[0238] 2> Indicate to the upper layer (to trigger) the establishment of a PC5 unicast link with the target L2 U2N relay UE indicated by targetRelayUE-Identity;

[0239] 2> Apply the default configuration of SL-RLC1 to SRB1;

[0240] 1> Otherwise (excluding sl-PathSwitchConfig):

[0241] 2> If the procedure is performed for an MCG, or if the procedure is performed for an SCG that is not indicated as deactivated in the E-UTRA or NR RRC message in which the RRCReconfiguration message is embedded:

[0242] 3>Start timer T304 for the corresponding SpCell, where the timer value is set to t304 as included in reconfigurationWithSync;

[0243] 2> If frequencyInfoDL is included:

[0244] 3> The target SpCell is regarded as the SpCell on the SSB frequency indicated by frequencyInfoDL, where the physical cell identity is indicated by physCellId;

[0245] 2> Otherwise:

[0246] 3> The target SpCell is regarded as the SpCell on the SSB frequency of the source SpCell, where the physical cell identity is indicated by physCellId;

[0247] 2> Start synchronization to the DL of the target SpCell;

[0248] 2> Apply the specified BCCH configuration to the target SpCell;

[0249] 2>Get the MIB of the target SpCell;

[0250] 2> If any DAPS bearer is configured:

[0251] 3> Create a MAC entity for the target cell group with the same configuration as the MAC entity for the source cell group;

[0252] 3> For each DAPS bearer:

[0253] 4> Establish one or more RLC entities for the target cell group with the same configuration as that for the source cell group;

[0254] 4> Establish a logical channel for the target cell group with the same configuration as that for the source cell group;

[0255] 3>For each SRB:

[0256] 4> Establish an RLC entity for the target cell group with the same configuration as that for the source cell group;

[0257] 4> Establish a logical channel for the target cell group with the same configuration as that for the source cell group;

[0258] 3>Suspend SRB for the source cell group;

[0259] 3> Apply the value of newUE-Identity as the C-RNTI in the target cell group;

[0260] 3>Configure the lower layer of the target SpCell according to the received spCellConfigCommon;

[0261] 3> If any additional fields are included in the received reconfigurationWithSync that were not covered in the previous reconfigurationWithSync, the lower layers of the target SpCell are configured according to these additional fields.

[0262] 2> Otherwise:

[0263] 3> Reset the MAC entity of the cell group;

[0264] 3> If the cell group is configured with an SCell that is not included in the SCellToAddModList in the RRCReconfiguration message, it is considered to be in a deactivated state;

[0265] 3> Apply the value of newUE-Identity as the C-RNTI for the cell group;

[0266] 3>Configure the lower layer according to the received spCellConfigCommon;

[0267] 3> If any additional fields are included in the received reconfigurationWithSync that were not covered in the previous reconfigurationWithSync, configure the lower layer according to these additional fields.

[0268] 2> If the UE is on the source side as L2 U2N remote UE:

[0269] 3> Instruct the upper layer to trigger the release of the PC5 unicast link.

[0270] For CHO, UE can:

[0271] 1>For each condReconfigId inside VarConditionalReconfig:

[0272] 2> If RRCReconfiguration in condRRCReconfig includes a masterCellGroup containing reconfigurationWithSync:

[0273] 3> A cell having a physical cell identifier that matches the value indicated in ServingCellConfigCommon included in reconfigurationWithSync in masterCellGroup in the received condRRCReconfig is considered as an applicable cell;

[0274] 2> Otherwise, if the RRCReconfiguration in condRRCReconfig includes a secondaryCellGroup that contains reconfigurationWithSync:

[0275] 3> A cell having a physical cell identifier that matches the value indicated in ServingCellConfigCommon included in reconfigurationWithSync in secondaryCellGroup in the received condRRCReconfig is considered as an applicable cell;

[0276] 2>If condExecutionCondSCG is configured:

[0277] 3> In the rest of the process, each measId indicated in condExecutionCondSCG is treated as a measId in the VarmeasConfig associated with the SCG measConfig;

[0278] 2>If condExecutionCond is configured:

[0279] 3> If it is configured via SRB3 or configured via SRB1 in nr-SCG or in nr-SecondaryCellGroupConfig:

[0280] 4> In the rest of the process, each measId indicated in condExecutionCond is treated as a measId in the VarMeasConfig associated with SCGmeasConfig;

[0281] 3> Otherwise:

[0282] 4> In the rest of the process, each measId indicated in condExecutionCond is treated as a measId in the VarMeasConfig associated with MCGmeasConfig;

[0283] 2> For each measId included in the measIdList within the VarMeasConfig indicated in the condExecutionCond or condExecutionCondSCG associated with condReconfigId:

[0284] 3> if condEventId is associated with condEventT1, and if the entry conditions applicable to the event associated with condReconfigId (i.e., the event corresponding to the condEventId of the corresponding condTriggerConfig within VarConditionalReconfig) are satisfied for the applicable cell; or

[0285] 3> if condEventId is associated with condEventD1, and if the entry conditions applicable to the event associated with condReconfigId (i.e., the event corresponding to the condEventId of the corresponding condTriggerConfig in VarConditionalReconfig) are satisfied for the applicable cell during the corresponding timeToTrigger defined for the event in VarConditionalReconfig; or

[0286] 3> If condEventId is associated with condEventA3, condEventA4, or condEventA5, and if the entry condition applicable to the event associated with condReconfigId (i.e., the event corresponding to the condEventId of the corresponding condTriggerConfig in VarConditionalReconfig) is met for all measurements made after layer 3 filtering during the corresponding timeToTrigger defined for the event in VarConditionalReconfig, for the applicable cells:

[0287] 4> The event associated with the measId is considered satisfied;

[0288] 3> If the measId of the event associated with condReconfigId has been modified; or

[0289] 3> if condEventId is associated with condEventT1, and if the leaving condition applicable to the event associated with condReconfigId (i.e., the event corresponding to the condEventId of the corresponding condTriggerConfig within VarConditionalReconfig) is satisfied for the applicable cell; or

[0290] 3> if condEventId is associated with condEventD1, and if the leaving condition applicable to the event associated with condReconfigId (i.e., the event corresponding to the condEventId of the corresponding condTriggerConfig in VarConditionalReconfig) is satisfied for the applicable cell during the corresponding timeToTrigger defined for the event in VarConditionalReconfig; or

[0291] 3> If condEventId is associated with condEventA3, condEventA4, or condEventA5, and if the leaving condition applicable to the event associated with condReconfigId (i.e., the event corresponding to the condEventId of the corresponding condTriggerConfig in VarConditionalReconfig) is met for all measurements after layer 3 filtering during the corresponding timeToTrigger defined for the event in VarConditionalReconfig, for the applicable cells:

[0292] 4> Treat the event associated with this measId as unsatisfied:

[0293] 2> If the events associated with all measIds in condTriggerConfig for the target candidate cell in the stored condRRCReconfig are met:

[0294] 3> The target candidate cell associated with condReconfigId in the stored condRRCReconfig is regarded as the triggered cell;

[0295] 3>Start conditional reconfiguration execution;

[0296] The UE can:

[0297] 1> If there is more than one triggered cell:

[0298] 2> Select one of the triggered cells as the selected cell for conditional reconfiguration execution;

[0299] 1> Otherwise:

[0300] 2> Treat the triggered cell as the selected cell for conditional reconfiguration execution;

[0301] 1> For selected cells where conditional reconfiguration is performed:

[0302] 2> Apply the stored condRRCReconfig of the selected cell.

[0303] Fig. 9 An example of a method performed by a base station to which an implementation of the present disclosure is applied is shown.

[0304] In step S900 , the method includes sending a cell configuration for a first cell.

[0305] In step S910, the method includes sending a candidate cell configuration for a second cell. The second cell is added to a candidate cell list for mobility.

[0306] In step S920, the method includes sending a first mobility command, applying a candidate cell configuration for the second cell, adding the first cell to a candidate cell list for mobility, and retaining the cell configuration for the first cell.

[0307] In step S930 , after the wireless device receives the second mobility command, the retained cell configuration for the first cell is applied.

[0308] In addition, the above Fig. 9 The method described in the perspective of the base station serving the second serving cell may be performed by Figure 2 The second wireless device 200 shown in FIG.

[0309] The base station includes at least one transceiver, at least one processor, and at least one memory capable of being operatively connected to the at least one processor and storing instructions that are executed based on being executed by the at least one processor. Fig. 9 The method described in .

[0310] More specifically, the base station sends a cell configuration for the first cell.

[0311] The base station sends a candidate cell configuration for the second cell and adds the second cell to a candidate cell list for mobility.

[0312] The base station sends a first mobility command. The candidate cell configuration for the second cell is applied. The first cell is added to a candidate cell list for mobility. The cell configuration for the first cell is retained.

[0313] After the wireless device receives the second mobility command, the retained cell configuration for the first cell is applied.

[0314] Various embodiments of the present disclosure are described below.

[0315] 1. Network-controlled service cell change

[0316] (1) Case 1: The UE receives a mobility command for serving cell change, where the mobility command is sent via L1 / L2 signaling (ie, L1 / L2 mobility or LTM).

[0317] The UE may regard the candidate serving cell indicated by the mobility command as the target cell, and thus regard the configuration for the candidate serving cell as the configuration for the target cell.

[0318] The UE may apply the configuration of the target cell. The UE may send a first message to the target cell, wherein the first message may be sent via any one of L1 signaling (e.g., PUCCH, PUSCH, etc.), L2 signaling (e.g., MAC CE), or L3 signaling (e.g., RRCReconfigurationComplete message). The UE may receive a second message (i.e., ACK) from the target cell, wherein the second message means successful mobility execution.

[0319] The UE may consider the previous serving cell (i.e., the source cell in mobility) as a new candidate serving cell. The UE may maintain / retain the configuration / resources of the previous serving cell and may perform TA maintenance, RLM / BFD, and RRM measurements for the new candidate serving cell.

[0320] (2) Case 2: The UE receives a mobility command for serving cell change, wherein the mobility command is sent via L3 signaling and includes an indicator indicating that the source cell is changed to a candidate serving cell after successful mobility execution.

[0321] The UE may apply the configuration of the target cell. The UE may perform a random access procedure to the target cell. The UE may send a first message to the target cell, wherein the first message may be sent via L3 signaling (e.g., an RRCReconfigurationComplete message). The UE may receive a second message (i.e., ACK) from the target cell, wherein the second message means successful mobility execution.

[0322] The UE may consider the previous serving cell (i.e., the source cell in mobility) as a new candidate serving cell. The UE may maintain / retain the configuration / resources of the previous serving cell and may perform TA maintenance, RLM / BFD, and RRM measurements for the new candidate serving cell.

[0323] (3) Case 3 (legacy operation): The UE receives a mobility command for serving cell change, where the mobility command is sent via L3 signaling and does not include an indicator indicating that the source cell is changed to a candidate serving cell after successful mobility execution.

[0324] The UE may apply the configuration of the target cell. The UE may perform a random access procedure to the target cell. The UE may send a first message to the target cell, wherein the first message may be sent via L3 signaling (e.g., an RRCReconfigurationComplete message). The UE may receive a second message (i.e., ACK) from the target cell, wherein the second message means successful mobility execution.

[0325] The UE may release resources and configuration for the previous serving cell (i.e., source cell) and stop DL / UL reception / transmission with the source cell. The UE may receive the configuration of a new candidate serving cell, where the new candidate serving cell is the same as the previous serving cell. The UE may perform a random access procedure on the new candidate serving cell. The UE may perform TA maintenance, RLM / BFD, and RRM measurements on the new candidate serving cell.

[0326] 2. UE autonomous serving cell change (e.g. conditional mobility)

[0327] (1) Case 1: The configuration of conditional mobility includes an indicator indicating that the source cell is changed to a candidate serving cell after successful mobility execution.

[0328] If the execution condition of conditional mobility is met for the target cell, the UE may apply the configuration of the target cell. The UE may perform a random access procedure to the target cell. The UE may send a first message to the target cell, where the first message may be sent via L3 signaling (e.g., RRCReconfigurationComplete message). The UE may receive a second message (i.e., ACK) from the target cell, where the second message means successful mobility execution.

[0329] The UE may consider the previous serving cell (i.e., the source cell in mobility) as a new candidate serving cell. The UE may maintain / retain the configuration / resources of the previous serving cell and may perform TA maintenance, RLM / BFD, and RRM measurements for the new candidate serving cell.

[0330] (2) Case 2 (legacy operation): The configuration for conditional mobility does not include an indicator indicating that the source cell is changed to a candidate serving cell after successful mobility execution.

[0331] If the execution condition of conditional mobility is met for the target cell, the UE may apply the configuration of the target cell. The UE may perform a random access procedure to the target cell. The UE may send a first message to the target cell, where the first message may be sent via L3 signaling (e.g., RRCReconfigurationComplete message). The UE may receive a second message (i.e., ACK) from the target cell, where the second message means successful mobility execution.

[0332] The UE may release resources and configuration for the previous serving cell (i.e., the source cell) and stop DL / UL reception / transmission with the source cell. The UE may receive the configuration of a new candidate serving cell, where the new candidate serving cell is the same as the previous serving cell. The UE may perform a random access procedure on the new candidate serving cell. The UE may perform TA maintenance, RLM / BFD, and RRM measurements for the new candidate serving cell.

[0333] 3. Network-controlled cell group changes

[0334] (1) Case 1: The UE receives a mobility command for a cell group change, wherein the mobility command includes an indicator indicating that the source cell group is changed to a candidate cell group after successful mobility execution.

[0335] The UE may apply the configuration of the target cell group. The UE may send a first message to the PCell of the target cell group, wherein the first message may be sent via L3 signaling (e.g., an RRCReconfigurationComplete message). The UE may receive a second message (i.e., ACK) from a cell included in the target cell group, wherein the second message means successful mobility execution.

[0336] The UE may regard the previous serving cell group (ie, the source cell group) as a new candidate serving cell group. The UE may maintain / retain the configuration / resources of the previous serving cell group and may perform TA maintenance, RLM / BFD and RRM measurements for the PCell of the new candidate serving cell group.

[0337] (2) Case 2 (legacy operation): The UE receives a mobility command for a cell group change, wherein the mobility command does not include an indicator indicating that the source cell group is changed to a candidate cell group after successful mobility execution.

[0338] The UE may apply the configuration of the target cell group. The UE may send a first message to the PCell of the target cell group, wherein the first message may be sent via L3 signaling (e.g., an RRCReconfigurationComplete message). The UE may receive a second message (i.e., ACK) from a cell included in the target cell group, wherein the second message means successful mobility execution.

[0339] The UE may release resources and configuration for the previous serving cell group (i.e., the source cell group) and stop DL / UL reception / transmission with the source cell group. The UE may receive the configuration of a new candidate serving cell group, where the new candidate serving cell group is the same as the previous serving cell group. The UE may perform a random access procedure on the PCell of the new candidate serving cell group. The UE may perform TA maintenance, RLM / BFD, and RRM measurements on the PCell of the new candidate serving cell group.

[0340] 4. UE autonomous cell group change (e.g. conditional mobility)

[0341] (1) Case 1: The configuration for conditional mobility includes an indicator indicating that the source cell group is changed to the candidate cell group after successful mobility execution.

[0342] If the execution condition of conditional mobility is met for the target cell group, the UE may apply the configuration of the target cell group. The UE may send a first message to the PCell of the target cell group, wherein the first message may be sent via L3 signaling (e.g., RRCReconfigurationComplete message). The UE may receive a second message (i.e., ACK) from a cell included in the target cell group, wherein the second message means successful mobility execution.

[0343] The UE may regard the previous serving cell group (ie, the source cell group) as a new candidate serving cell group. The UE may maintain / retain the configuration / resources of the previous serving cell group and may perform TA maintenance, RLM / BFD and RRM measurements for the PCell of the new candidate serving cell group.

[0344] (2) Case 2 (legacy operation): The configuration for conditional mobility does not include an indicator indicating that the source cell group is changed to a candidate serving cell after successful mobility execution.

[0345] If the execution condition of conditional mobility is met for the target cell group, the UE may apply the configuration of the target cell group. The UE may send a first message to the PCell of the target cell group, wherein the first message may be sent via L3 signaling (e.g., RRCReconfigurationComplete message). The UE may receive a second message (i.e., ACK) from a cell included in the target cell group, wherein the second message means successful mobility execution.

[0346] The UE may release resources and configuration for the previous serving cell group (i.e., the source cell group) and stop DL / UL reception / transmission with the source cell group. The UE may receive the configuration of a new candidate serving cell group, where the new candidate serving cell group is the same as the previous serving cell group. The UE may perform a random access procedure to the Pcell of the new candidate serving cell group. The UE may perform TA maintenance, RLM / BFD, and RRM measurements for the PCell of the new candidate serving cell group.

[0347] The present disclosure may have various beneficial effects.

[0348] For example, the UE may maintain source resources and configurations, and may perform TA maintenance and BFD / RLM after successful mobility execution.

[0349] For example, the UE may perform RACH-free mobility to a candidate serving cell.

[0350] For example, the delay and interruption time caused by the UE performing RACH can be reduced.

[0351] The beneficial effects obtained by the specific examples of this specification are not limited to the effects listed above. For example, there may be a variety of technical effects that can be understood or derived from this specification by a person of ordinary skill in the art. Therefore, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that can be understood or derived from the technical features of the present disclosure.

[0352] The claims in this disclosure can be combined in various ways. For example, the technical features in the method claims of this disclosure can be combined to be implemented or performed in a device, and the technical features in the device claims can be combined to be implemented or performed in a method. In addition, the technical features in the method claims and the device claims can be combined to be implemented or performed in a device. In addition, the technical features in the method claims and the device claims can be combined to be implemented or performed in a method. Other implementations are within the scope of the appended claims.

Claims

1. A method performed by a wireless device adapted to operate in a wireless communication system, the method comprising the steps of: receiving a cell configuration for a first cell; receiving a candidate cell configuration for the second cell, wherein the second cell is added to a candidate cell list for mobility; upon receiving a first mobility command, applying the candidate cell configuration for the second cell, wherein the first cell is added to the candidate cell list for mobility; retaining the cell configuration for the first cell; and Upon receiving a second mobility command, applying the retained cell configuration for the first cell.

2. The method according to claim 1, wherein: The first mobility command and / or the second mobility command are received via any one of L1 signaling, L2 signaling or L3 signaling.

3. The method according to claim 1 or claim 2, wherein: The mobility includes at least one of a serving cell change controlled by a network or an autonomous serving cell change of a user equipment UE.

4. The method according to any one of claims 1 to 3, wherein: The first mobility command includes the candidate cell configuration for the second cell.

5. The method according to any one of claims 1 to 3, wherein: Based on the first mobility command not including the candidate cell configuration for the second cell, the first mobility command includes an identifier of the second cell.

6. The method according to any one of claims 1 to 5, wherein: The first mobility command comprises a conditional reconfiguration.

7. The method according to any one of claims 1 to 6, wherein: Explicit information notifying that the first cell is to be added to the candidate list is included in one of the cell configuration or the first mobility command for the first cell.

8. The method according to claim 7, wherein: The cell configuration for the first cell is retained based on the explicit information.

9. The method according to claim 7, wherein: The explicit information is configured per pair of a target cell and a source cell.

10. The method according to claim 9, wherein: The source cell is added to the candidate cell list for mobility based on applying only the candidate cell configuration for the target cell.

11. The method according to any one of claims 1 to 6, wherein: The first mobility command received via either L1 signaling or L2 signaling implicitly notifies that the first cell is to be added to the candidate list.

12. The method according to claim 11, wherein: The cell configuration for the first cell is retained based on the first mobility command received via either L1 signaling or L2 signaling.

13. The method according to any one of claims 1 to 12, wherein: Upon receiving the candidate cell configuration for the second cell, the first cell is added to the candidate cell list for mobility.

14. The method according to any one of claims 1 to 12, wherein: When applying the candidate cell configuration for the second cell, the first cell is added to the candidate cell list for mobility.

15. The method according to any one of claims 1 to 14, wherein: When applying the candidate cell configuration for the second cell, a first message is sent to the second cell.

16. The method according to claim 15, wherein: The first message is sent via any one of L1 signaling, L2 signaling or L3 signaling.

17. The method according to any one of claims 1 to 16, wherein: A second message is received from the second cell in response to the first message.

18. The method according to claim 17, wherein: The second message notifies that the mobility to the second cell is successfully performed.

19. The method according to any one of claims 1 to 18, wherein: While retaining the cell configuration for the first cell, at least one of the following is performed for the first cell: i) timing advance TA maintenance, ii) beam failure detection BFD, or iii) radio link monitoring RLM.

20. The method according to any one of claims 1 to 19, wherein: The wireless device communicates with at least one of a mobile device other than the wireless device, a network, and / or an autonomous vehicle.

21. A wireless device adapted to operate in a wireless communication system, the wireless device comprising: at least one transceiver; at least one processor; as well as At least one memory, the at least one memory being operatively connected to the at least one processor and storing instructions, the instructions executing the method according to any one of claims 1 to 20 upon being executed by the at least one processor.

22. A processing device adapted to control a wireless device in a wireless communication system, the processing device comprising: at least one processor; as well as at least one memory operatively connectable to the at least one processor, The at least one processor is adapted to execute the method according to any one of claims 1 to claim 20.

23. A non-transitory computer readable medium (CRM) storing instructions, wherein the instructions are executed by at least one processor to perform the method according to any one of claims 1 to 20.

24. A method performed by a base station adapted to operate in a wireless communication system, the method comprising the steps of: Sending a cell configuration for the first cell; sending a candidate cell configuration for the second cell, wherein the second cell is added to a candidate cell list for mobility; and sending a first mobility command, wherein the candidate cell configuration for the second cell is applied, wherein the first cell is added to the candidate cell list for mobility, wherein the cell configuration for the first cell is retained, and After the wireless device receives the second mobility command, the reserved cell configuration for the first cell is applied.

25. A base station adapted to serve a second serving cell in a wireless communication system, the base station comprising: at least one transceiver; at least one processor; as well as At least one memory, the at least one memory being operatively connected to the at least one processor and storing instructions, the instructions performing the method according to claim 24 upon being executed by the at least one processor.

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