Avoid simultaneous conditional handover and conditional primary SCG cell change

Abstract

Example embodiments include methods, apparatus, and computer-readable media for wireless communications at a secondary node (SN), including determining a conditional primary SCG cell (PSCell) change (CPC) of a UE to one of a target primary SCG cell set within an SN that is different from a current primary secondary cell group SCG cell. The embodiment also includes generating a secondary cell modification message including identification information of the target primary SCG cell set of the CPC. Additionally, the embodiment includes sending a secondary cell modification message including identification information of the target primary SCG cell set of the CPC to a primary node (MN) associated with the UE. Additionally, the embodiment includes receiving a response message from the MN indicating confirmation or rejection of the secondary cell modification message. Example methods, apparatus, and computer-readable media for wireless communications at the MN are included.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. application serial number 63 / 016,283, filed on April 27, 2020, entitled “AVOIDING SIMULTANEOUS CONDITIONAL HANDOVER AND CONDITIONAL PRIMARY SCG CELL CHANGE,” and U.S. patent application serial number 17 / 240,524, filed on April 26, 2021, entitled “AVOIDING SIMULTANEOUS CONDITIONAL HANDOVER AND CONDITIONAL PRIMARY SCG CELL CHANGE,” the disclosures of which are incorporated herein by reference in their entirety. Technical Field

[0003] The present disclosure relates generally to communication systems, and more particularly, to apparatus and methods for avoiding simultaneous conditional handover (CHO) and conditional primary SCG cell change (CPC). Background Art

[0004] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, and broadcast. Typical wireless communication systems may employ multiple access technologies that are capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0005] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at municipal, national, regional and even global levels. An example of a telecommunication standard is 5G New Radio (NR). 5G NR is part of the continued mobile broadband evolution promulgated by the Third Generation Partnership Project (3GPP) to meet new requirements related to latency, reliability, security, scalability (e.g., Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC). Certain aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. Further improvements to 5G NR technology are needed. These improvements may also be applied to other multiple access technologies and telecommunication standards that adopt these technologies. In particular, improvements to network communication processes are needed. Summary of the invention

[0006] A simplified summary of one or more aspects is presented below in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all intended aspects, and is neither intended to identify key or important elements of all aspects, nor to delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that is presented later.

[0007] An example embodiment includes a method for wireless communication at a secondary node (SN), including determining to perform a conditional primary SCG cell group cell (PSCell or primary SCG cell) change (CPC) of a user equipment (UE) to one of a target primary SCG cell set within an SN that is different from a current primary SCG cell. The method also includes generating a secondary cell modification message including identification information of the target primary SCG cell set of the CPC. Additionally, the method also includes sending a secondary cell modification message including identification information of the target primary SCG cell set of the CPC to a master node (MN) associated with the UE. Additionally, the method also includes receiving a response message from the MN indicating confirmation or rejection of the secondary cell modification message.

[0008] Another example embodiment includes an apparatus for wireless communication at a secondary node (SN), the apparatus comprising a memory and a processor in communication with the memory. The processor is configured to determine a conditional primary SCG cell (PSCell or primary SCG cell) change (CPC) of a user equipment (UE) to one of a target primary SCG cell set within an SN different from a current primary SCG cell. The processor is also configured to generate a secondary cell modification message, the secondary cell modification message including identification information of a target primary SCG cell set of the CPC. Additionally, the processor is also configured to send a secondary cell modification message including identification information of a target primary SCG cell set of the CPC to a primary node (MN) associated with the UE. Additionally, the processor is also configured to receive a response message from the MN indicating confirmation or rejection of the secondary cell modification message.

[0009] Another example embodiment includes an apparatus for performing wireless communications at a secondary node (SN), including a component for determining a conditional primary SCG cell (PSCell or primary SCG cell) change (CPC) of a user equipment (UE) to one of a target primary SCG cell set within an SN that is different from a current primary SCG cell. The apparatus also includes a component for generating a secondary cell modification message including identification information of the target primary SCG cell set of the CPC. Additionally, the apparatus also includes a component for sending a secondary cell modification message including identification information of the target primary SCG cell set of the CPC to a primary node (MN) associated with the UE. Additionally, the apparatus also includes a component for receiving a response message from the MN indicating confirmation or rejection of the secondary cell modification message.

[0010] Another example embodiment includes a computer-readable medium including stored instructions for wireless communication at a secondary node (SN), the instructions being executable by a processor to determine a conditional primary SCG cell (PSCell or primary SCG cell) change (CPC) of a user equipment (UE) to one of a target primary SCG cell set within an SN different from a current primary SCG cell. The instructions are also executable to generate a secondary cell modification message including identification information of a target primary SCG cell set of the CPC. Additionally, the instructions are also executable to send a secondary cell modification message including identification information of a target primary SCG cell set of the CPC to a primary node (MN) associated with the UE. Additionally, the instructions are also executable to receive a response message from the MN indicating confirmation or rejection of the secondary cell modification message.

[0011] In another aspect, an example embodiment includes a method for wireless communication at a master node (MN), comprising receiving a secondary cell modification message for a user equipment (UE) from a secondary node (SN), wherein the secondary cell modification message includes identification information of a target primary SCG cell (PSCell or primary SCG cell) set for a conditional PSCell change (CPC) of the UE from a current primary secondary cell group (SCG) cell to a different primary SCG cell within the SN. The method also includes determining whether the target primary SCG cell set is suitable for performing CPC. Additionally, the method also includes sending a response message to the SN indicating confirmation or rejection of the secondary cell modification message.

[0012] Another example embodiment includes an apparatus for wireless communication at a master node (MN), the apparatus comprising a memory and a processor in communication with the memory. The processor is configured to receive a secondary cell modification message for a user equipment (UE) from a secondary node (SN), wherein the secondary cell modification message includes identification information of a target primary SCG cell (PSCell or primary SCG cell) set for a conditional PSCell change (CPC) of the UE from a current primary and secondary cell group (SCG) cell to a different primary SCG cell within the SN. The processor is also configured to determine whether the target primary SCG cell set is suitable for performing CPC. Additionally, the processor is also configured to send a response message to the SN indicating confirmation or rejection of the secondary cell modification message.

[0013] Another example embodiment includes an apparatus for wireless communication at a master node (MN), including a component for receiving a secondary cell modification message for a user equipment (UE) from a secondary node (SN), wherein the secondary cell modification message includes identification information of a target primary SCG cell (PSCell or primary SCG cell) set for a conditional PSCell change (CPC) of the UE from a current primary secondary cell group (SCG) cell to a different primary SCG cell within the SN. The apparatus also includes a component for determining whether the target primary SCG cell set is suitable for performing CPC. Additionally, the apparatus also includes a component for sending a response message to the SN indicating confirmation or rejection of the secondary cell modification message.

[0014] Another example embodiment includes a computer-readable medium including instructions stored therein for wireless communication at a master node (MN), the instructions being executable by a processor to receive a component of a secondary cell modification message for a user equipment (UE) from a secondary node (SN), wherein the secondary cell modification message includes identification information of a target primary SCG cell (PSCell or primary SCG cell) set for a conditional PSCell change (CPC) of the UE from a current primary secondary cell group (SCG) cell to a different primary SCG cell within the SN. The instructions may also be executed to determine whether the target primary SCG cell set is suitable for performing CPC. Additionally, the instructions may also be executed to send a response message to the SN indicating confirmation or rejection of the secondary cell modification message.

[0015] To achieve the foregoing and related ends, one or more aspects described above include the features fully described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail certain illustrative features of one or more aspects described above. However, these features are indicative of only some of the various ways in which the principles of the various aspects may be employed, and this description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is an example diagram of a wireless communication system and access network, including a base station configured to avoid CPC and CHO conflicts.

[0017] Figure 2A is a diagram illustrating an example of a first 5G / NR frame in accordance with certain aspects of the present disclosure.

[0018] Figure 2B is a diagram illustrating an example of DL channels in a 5G / NR subframe in accordance with certain aspects of the present disclosure.

[0019] Figure 2C is a diagram illustrating an example of a second 5G / NR frame in accordance with certain aspects of the present disclosure.

[0020] Figure 2D is a diagram illustrating an example of UL channels in a 5G / NR subframe in accordance with certain aspects of the present disclosure.

[0021] Figure 3 is an example diagram of components of a base station and a user equipment.

[0022] Figure 4 is a schematic diagram of an example dual connectivity architecture in which features of the present disclosure may be implemented.

[0023] Figure 5 is a message flow diagram of a wireless communication method for avoiding CPC and CHO conflicts according to aspects described herein.

[0024] Figure 6 is a message flow diagram of a wireless communication method for canceling CPC according to aspects described herein.

[0025] Figure 7 is a block diagram of a SN including components for performing the actions described herein.

[0026] Figure 8 is a flow chart of a first example method of wireless communications by a SN to avoid CPC and CHO conflicts as described herein.

[0027] Fig. 9 is a flow chart of a second example method for wireless communications by a SN to avoid CPC and CHO conflicts as described herein.

[0028] Fig.10 is a flow chart of a third example of wireless communications by a SN to avoid CPC and CHO conflicts as described herein.

[0029] Fig.11 is a flow chart of a fourth example method of wireless communications by a SN to avoid CPC and CHO conflicts as described herein.

[0030] Fig.12 is a block diagram of a MN including components for performing the actions described herein.

[0031] Fig.13 is a flow chart of a first example method for wireless communications by a MN to avoid CPC and CHO conflicts as described herein.

[0032] Fig.14 is a flow chart of a second example method for wireless communications by a MN to avoid CPC and CHO conflicts as described herein.

[0033] Fig.15 is a flow chart of a third example method for wireless communications by a MN to avoid CPC and CHO conflicts as described herein.

[0034] Fig.16 is a flow chart of a fourth example method for wireless communications by a MN to avoid CPC and CHO conflicts as described herein.

[0035] Fig.17 is a flow chart of a fifth example method for wireless communications by a MN to avoid CPC and CHO conflicts as described herein. DETAILED DESCRIPTION

[0036] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various configurations, and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details in order to provide a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring these concepts.

[0037] The present disclosure relates generally to wireless communication systems, and more particularly to avoiding simultaneous conditional handover (CHO) and conditional primary secondary cell group cell (PSCell) change (CPC). In multi-radio dual connectivity (MR-DC) and new radio dual connectivity (NR-DC), CHO (conditional handover) may conflict with CPC (conditional primary SCG cell (PSCell) change). In other words, a user equipment (UE) may receive both CHO and CPC requests and be confused about which request to follow, and / or a race condition may be triggered by receiving both CHO and CPC requests.

[0038] The present disclosure provides an apparatus and method for enabling a secondary node (SN) to notify a primary node (MN) of CPC and include a CPC target PSCell list. For example, the SN may include a CPC target PSCell list in a modification message (such as in an information element of a modification request message). This provides notification of the CPC to the MN and allows the MN to determine whether the target PSCell in the list is suitable for the CPC process. In response, based on the suitability of one or more target PSCells, the SN receives acceptance or rejection of the modification message and, therefore, receives acceptance or rejection of the CPC. In some cases, the SN may receive a response identifying a rejected CPC PSCell list and / or an approved CPC PSCell list.

[0039] In addition, the SN may inform the MN when the CPC is completed by sending a new message (such as an SN Modification Complete message) or by performing a PSCell Change procedure.

[0040] On the other hand, the present disclosure provides an apparatus and method for the SN to receive a CPC cancellation message from the MS even after receiving confirmation of the CPC procedure. For example, the MN may determine that the UE is about to lose connection and should be handed over. In this case, the MN may initiate CHO and send a CPC cancellation indication to the SN. This terminates the CPC procedure and enables the UE to hand over to a new cell based on CHO.

[0041] On the other hand, the present disclosure provides an apparatus and method for enabling a MN to enable or disable CPC. In some examples, CPC can be an inter-CPC process (e.g., for conditional SN changes), or an intra-CPC process. In this case, before initiating CHO, the MN informs the SN not to perform CPC by including a prohibition or disallowance indication (e.g., "prohibit CPC" or "do not allow CPC") in the X2 / Xn SN modification / addition request to prohibit CPC during CHO. Optionally, when there is no conflict with CHO, the MN can include a "CPC allowed" indication in the SN modification / addition request message. After CHO, the target MN can remove the CPC restriction by including "CPC allowed" in the SN modification process.

[0042] In yet another aspect, the present disclosure provides apparatus and methods that allow other network implementations (such as via operations, management, and administration (OAM) entities) to avoid simultaneous CPC and CHO. For example, any signaling described herein, such as but not limited to the "disable CPC" mentioned above, can be carried on OAM signaling.

[0043] Therefore, the present solution improves the efficiency of wireless network operations at network-based entities (eg, base stations) and UEs.

[0044] Several aspects of telecommunication systems will now be described with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0045] For example, an element or any part of an element or any combination of elements may be implemented as a "processing system" comprising one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gating logic, discrete hardware circuits, and other suitable hardware that are configured to perform various functions described throughout this disclosure. One or more processors in a processing system may execute software. Software should be broadly interpreted as instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, processes, functions, etc., whether or not referred to as software, firmware, middleware, microcode, hardware description languages, or other.

[0046] Therefore, in one or more example embodiments, the described functions may be implemented in hardware, software, or any combination thereof. If implemented in software, the function may be stored on a computer-readable medium or encoded as one or more instructions or codes on a computer-readable medium. A computer-readable medium includes a computer storage medium. A storage medium may be any available medium that a computer can access. By way of example and not limitation, such a computer-readable medium may include a random access memory (RAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), an optical disk storage, a magnetic disk storage, other magnetic storage devices, a combination of the above-mentioned types of computer-readable media, or any other medium that may be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

[0047] refer to Figure 1, an example of a wireless communication system and access network 100 (also referred to as a wireless wide area network (WWAN)) includes a base station 102, the base station 102 including a master node (MN) and a secondary node (SN) communicating with a user equipment (UE) 104, wherein one or more base stations 102 are configured to avoid simultaneous CPC and CHO as described herein. For example, one or more base stations 102 may include a secondary node (SN) 103 operating a CHO / CPC conflict component 105, and the CHO / CPC conflict component 105 is configured to avoid CPC and CHO process conflicts. Similarly, one or more base stations 102 may include a master node (SN) 115 operating a CPC / CHO component 117, which is configured to communicate in cooperation with the CHO / CPC conflict component 105 of the SN 103 to avoid CPC and CHO process conflicts. The operating details of these components will be described in more detail below. Therefore, the present solution improves network communications at one or more base stations 102 and reduces confusion or errors at the UE 104.

[0048] In the wireless communication system and access network 100, the base station 102 and the UE 104 can additionally communicate with an evolved packet core (EPC) 160 and / or another core network 190 (such as, but not limited to, a 5G core (5GC)). The base station 102 can include a macro cell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). A macro cell includes a base station. A small cell includes a femto cell, a pico cell, and a micro cell.

[0049] The base station 102 configured for 4G LTE (collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can interface with the EPC 160 via a first backhaul link 132 (e.g., an S1 interface). The base station 102 configured for 5G NR (collectively referred to as the Next Generation RAN (NG-RAN)) can interface with the core network 190 via a second backhaul link 184. Among other functions, the base station 102 can perform one or more of the following functions: transmission of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and device tracking, RAN information management (RIM), paging, positioning, and transmission of warning messages. The base stations 102 may communicate with each other directly or indirectly (eg, through the EPC 160 or the core network 190) via a third backhaul link 134 (eg, an X2 interface). The third backhaul link 134 may be wired or wireless.

[0050] Base station 102 can communicate wirelessly with UE 104. Each base station 102 can provide communication coverage for its own geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, a small cell 102' can have a coverage area 110' that overlaps with the coverage area 110 of one or more macro base stations 102. A network including both small cells and macro cells can be referred to as a heterogeneous network. A heterogeneous network can also include a home evolution node base station (eNB) (HeNB), which can provide services to a restricted group called a closed subscriber group (CSG). The communication link 120 between base station 102 and UE 104 can include an uplink (UL) (also called a reverse link) transmission from UE 104 to base station 102 and / or a downlink (DL) (also called a forward link) transmission from base station 102 to UE 104. The communication link 120 can use multiple input multiple output (MIMO) antenna technology, including spatial multiplexing, beamforming and / or transmit diversity. The communication link can be through one or more carriers. The base station 102 / UE 104 may use spectrum bandwidth of up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) per carrier allocated in carrier aggregation for a total of up to Yx MHz (x component carriers) for transmission in each direction. The carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​than for UL). The component carrier may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell) and the secondary component carrier may be referred to as a secondary cell (SCell).

[0051] Some UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use DL / UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). The D2D communication may be through various wireless D2D communication systems, such as, for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on IEEE 802.11 standards, LTE, or NR.

[0052] The wireless communication system may also include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 in the 5 GHz unlicensed spectrum via a communication link 154. When communicating in the unlicensed spectrum, the STA 152 / AP 150 may perform a clear channel assessment (CCA) prior to communication to determine whether the channel is available.

[0053] The small cell 102' can operate in a licensed and / or unlicensed spectrum. When operating in an unlicensed spectrum, the small cell 102' can use NR and use the same 5 GHz unlicensed spectrum used by the Wi-Fi AP 150. The small cell 102' using NR in the unlicensed spectrum can improve the coverage of the access network and / or increase the capacity of the access network.

[0054] Whether a small cell 102' or a large cell (e.g., a macro base station), the base station 102 may include and / or be referred to as an eNB, a gNodeB (gNB), or another type of base station. Some base stations (e.g., gNB 180) may operate in the traditional sub-6 GHz spectrum at millimeter wave (mmW) frequencies and / or near mmW frequencies to communicate with the UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as a mmW base station. Extremely high frequency (EHF) is a portion of the RF in the electromagnetic spectrum. The EHF range is between 30 GHz and 300 GHz, with wavelengths between 1 mm and 10 mm. The radio waves in this band may be referred to as millimeter waves. Near mmW can extend down to frequencies of 3 GHz with wavelengths of 100 mm. The super high frequency (SHF) band extends between 3 GHz and 30 GHz and is also referred to as centimeter waves. Communications using mmW / near mmW radio frequency bands (e.g., 3 GHz-300 GHz) have extremely high path losses and very short distances. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short distance. The base station 180 and the UE 140 may each include multiple antennas, such as antenna elements, antenna panels, and / or antenna arrays, to facilitate beamforming.

[0055] Base station 180 may transmit beamformed signals in one or more transmit directions 182' to UE 140. UE 104 may receive beamformed signals from base station 180 in one or more receive directions 182". UE 104 may transmit beamformed signals to base station 180 in one or more transmit directions. Base station 180 may receive beamformed signals from UE 104 in one or more receive directions. Base station 180 / UE 104 may perform beam training to determine the best receive and transmit directions for each of base station 180 / UE 104. The transmit and receive directions of base station 180 may be the same or different. The transmit and receive directions of UE 104 may be the same or different.

[0056] The EPC 160 may include a mobility management entity (MME) 162, other MMEs 164, a serving gateway 166, a multimedia broadcast multicast service (MBMS) gateway 168, a broadcast multicast service center (BM-SC) 170, and a packet data network (PDN) gateway 172. The MME 162 may communicate with a home subscriber server (HSS) 174. The MME 162 is a control node that handles signaling between the UE 104 and the EPC 160. Typically, the MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are transmitted through the serving gateway 166, which itself is coupled to the PDN gateway 172. The PDN gateway 172 provides IP address allocation and other functions for the UE. The PDN gateway 172 and the BM-SC 170 are coupled to IP services 176. The IP services 176 may include the Internet, an intranet, an IP multimedia subsystem (IMS), PS streaming services, and / or other IP services. The BM-SC 170 may provide service provisioning and delivery functions for MBMS users. The BM-SC 170 may serve as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services within a public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS traffic to base stations 102 belonging to a multicast broadcast single frequency network (MBSFN) area broadcasting a specific service, and may be responsible for session management (start / stop) and collecting eMBMS-related billing information.

[0057] The core network 190 may include an access and mobility management function (AMF) 192, other AMFs 193, a session management function (SMF) 194, and a user plane function (UPF) 195. AMF 192 may communicate with a unified data management (UDM) 196. AMF 192 is a control node that handles signaling between UE 104 and the core network 190. Typically, AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are transmitted through UPF 195. UPF 195 provides UE IP address allocation and other functions. UPF 195 is coupled to IP services 197. IP services 197 may include the Internet, intranet, IP multimedia subsystem (IMS), PS streaming services, and / or other IP services.

[0058] A base station may include and / or be referred to as a gNB, a Node B, an eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit receive point (TRP), or some other suitable term. Base station 102 provides an access point to EPC 160 or core network 190 for UE 104. Examples of UE 104 include a cellular phone, a smart phone, a Session Initiation Protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., an MP3 player), a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor / actuator, a display, or any other similar functional device. Some UEs 104 may be referred to as IoT devices (e.g., a parking meter, a gas pump, a toaster, a vehicle, a heart monitor, etc.). UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

[0059] refer to Figures 2A to 2D , base station 102 and / or UE 104 may utilize examples of different frame structures and resources to conduct communications as described herein. Figure 2A FIG200 is a diagram showing an example of a first subframe within a 5G / NR frame structure. Figure 2B FIG230 is a diagram showing an example of DL channels within a 5G / NR subframe. Figure 2C Figure 250 shows an example of a second subframe within a 5G / NR frame structure. Figure 2D 280 is a diagram showing an example of UL channels within a 5G / NR subframe. The 5G / NR frame structure may be FDD, where for a particular set of subcarriers (carrier system bandwidth), subframes within a subcarrier set are dedicated to either DL or UL, or may be TDD, where for a particular set of subcarriers (carrier system bandwidth), subframes within a subcarrier set are dedicated to both DL and UL. Figure 2A , 2CIn the example provided, it is assumed that the 5G / NR frame structure is TDD, where subframe 4 is configured with slot format 28 (mostly DL), where D is DL, U is UL, and X is flexibly used between DL / UL, and subframe 3 is configured with slot format 34 (mostly UL). Although subframes 3 and 4 are shown with slot formats 34 and 28, respectively, any particular subframe can be configured with any of the various available slot formats 0-61. Slot formats 0 and 1 are DL and UL, respectively. Other slot formats 2-61 include a mix of DL, UL and flexible codewords. The UE is configured with the slot format (dynamically through DL control information (DCI), or semi-statically / statically through radio resource control signaling) through the received slot format indicator (SFI). Note that the following description also applies to the 5G / NR frame structure as TDD.

[0060] Other wireless communication technologies may have different frame structures and / or different channels. A frame (10ms) may be divided into 10 equally sized subframes (1ms). Each subframe may include one or more time slots. A subframe may also include small slots, which may include 7, 4, or 2 symbols. Depending on the time slot configuration, each time slot may include 7 or 14 symbols. For time slot configuration 0, each time slot may include 14 symbols; for time slot configuration 1, each time slot may include 7 symbols. The symbols on the DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols. The symbols on the UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also called single carrier frequency division multiple access (SC-FDMA) symbols) (for power-limited scenarios; limited to single stream transmission). The number of time slots within a subframe is based on the time slot configuration and parameter set. For slot configuration 0, different parameter sets μ0 to 5 allow 1, 2, 4, 8, 16 and 32 slots per subframe, respectively. For slot configuration 1, different parameter sets 0 to 2 allow 2, 4 and 8 slots per subframe, respectively. Therefore, for slot configuration 0 and parameter set μ, there are 14 symbols / slot and 2μ slots / subframe. The subcarrier spacing and symbol length / duration are functions of the parameter set. The subcarrier spacing can be equal to 2 μ *15kHz, where μ is parameter set 0 to 5. Thus, parameter set μ=0 has a subcarrier spacing of 15kHz and subcarrier μ=5 has a subcarrier spacing of 480kHz. The symbol length / duration is inversely proportional to the subcarrier spacing. Figures 2A-2D An example of slot configuration 0 is provided, with 14 symbols per slot, parameter set μ=2, and 4 slots per subframe. The slot duration is 0.25ms, the subcarrier spacing is 60kHz, and the symbol duration is approximately 16.67μs.

[0061] A resource grid can be used to represent the frame structure. Each time slot includes a resource block (RB) (also called a physical RB (PRB)) extending over 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0062] like Figure 2A As shown in , a portion of the REs carry reference (pilot) signals (RS) for the UE. The RS may include a demodulation RS (DM-RS) (indicated as Rx for a particular configuration, where 100x is the port number, but other DM-RS configurations are also possible) and a channel state information reference signal (CSI-RS) for channel estimation at the UE. The RS may also include a beam measurement RS (BRS), a beam refinement RS (BRRS), and a phase tracking RS (PT-RS).

[0063] Figure 2B Examples of various DL channels within a subframe of a frame are shown. The physical downlink control channel (PDCCH) carries DCI in one or more control channel elements (CCEs), each CCE including nine RE groups (REGs), each REG including four consecutive REs in an OFDM symbol. The primary synchronization signal (PSS) may be within symbol 2 of a particular subframe of a frame. The PSS is used by UE 104 to determine subframe / symbol timing and physical layer identification. The secondary synchronization signal (SSS) may be within symbol 4 of a particular subframe of a frame. The SSS is used by the UE to determine the physical layer cell identification group number and radio frame timing. Based on the physical layer identification and the physical layer cell identification group number, the UE may determine the physical cell identifier (PCI). Based on the PCI, the UE may determine the location of the aforementioned DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) may be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block. The MIB provides the number of RBs in the system bandwidth and the system frame number (SFN). The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information not sent through the PBCH, such as System Information Blocks (SIBs), and paging messages.

[0064] like Figure 2CAs shown, some of the REs carry DM-RS for channel estimation at the base station (indicated as R for a specific configuration, but other DM-RS configurations are also possible). The UE can send DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH). The PUSCH DM-RS can be sent in the first one or two codewords in the PUSCH. Depending on whether a short or long PUCCH is sent and depending on the specific PUCCH format used, the PUCCH DM-RS can be sent in different configurations. The UE can send a sounding reference signal (SRS). The SRS can be transmitted in the last codeword of the subframe. The SRS can have a comb structure, and the UE can send the SRS on one of the comb structures. The base station can use the SRS for channel quality estimation to achieve frequency-dependent scheduling on the UL.

[0065] Figure 2D Examples of various UL channels within a subframe of a frame are shown. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), and HARQ ACK / NACK feedback. The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0066] refer to Figure 3, example components of base station 102 and UE 104 are used to communicate with each other in access network 100. In the DL, IP packets from EPC 160 may be provided to controller / processor 375. Controller / processor 375 implements layer 3 and layer 2 functions. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a media access control (MAC) layer. The controller / processor 375 provides RRC layer functions associated with broadcasting of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functions associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functions associated with transmission of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation and assembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs to transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority processing, and logical channel prioritization.

[0067] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functions associated with various signal processing functions. Layer 1 (which includes the physical (PHY) layer) may include: error detection on the transmission channel, forward error correction (FEC) encoding / decoding of the transmission channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 processes the mapping to the signal constellation diagram based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase phase shift keying (M-PSK), M-order quadrature amplitude modulation (M-QAM)). Then, the coded and modulated codewords can be divided into parallel streams. Then, each stream can be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., a pilot) in the time domain and / or frequency domain, and then combined using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time domain OFDM codeword stream. The OFDM stream is spatially precoded to generate multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine coding and modulation schemes and for spatial processing. Channel estimates may be obtained from reference signals and / or channel condition feedback sent by the UE 104. Each spatial stream may then be provided to a different antenna 320 via a respective transmitter 318TX. Each transmitter 318TX may modulate an RF carrier using a respective spatial stream for transmission.

[0068] At the UE 104, each receiver 354RX receives a signal through its respective antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functions associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial stream destined for the UE 104. If multiple spatial streams are destined for the UE 104, the RX processor 356 can combine them into a single OFDM symbol stream. The RX processor 356 then transforms the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier and the reference signal are recovered and demodulated by determining the most likely signal constellation point sent by the base station 102. These soft decisions can be based on the channel estimates calculated by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally sent on the physical channel by base station 102. The data and control signals are then provided to controller / processor 359, which performs layer 3 and layer 2 functions.

[0069] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection, which supports HARQ operations using an ACK and / or NACK protocol.

[0070] Similar to the functions described in conjunction with DL transmissions performed by the base station 102, the controller / processor 359 provides: RRC layer functions associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functions associated with header compression / decompression, and security (encryption, decryption, integrity protection, integrity verification); RLC layer functions associated with transmission of upper layer PDUs, error correction through ARQ, concatenation, segmentation and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs to TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority processing, and logical channel prioritization.

[0071] Channel estimates derived by the channel estimator 358 from a reference signal or feedback transmitted by the base station 102 may be used by the TX processor 368 to select the appropriate coding and modulation schemes and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier using a respective spatial stream for transmission.

[0072] At the base station 102, the UL transmission is processed in a manner similar to that described in conjunction with the receiver functionality at the UE 104. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

[0073] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover IP packets from the UE 104. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection, which supports HARQ operations using an ACK and / or NACK protocol.

[0074] At the UE 104, at least one of the TX processor 368, the RX processor 356, and the controller / processor 359 may be configured to perform aspects related to the features discussed herein.

[0075] At the base station, at least one of the TX processor 316, the RX processor 370, and the controller / processor 375 may be configured to perform operations related to Figure 1 and / or aspects related to the CHO / CPC conflict component 105 and / or CPC / CHO component 117 as described elsewhere herein.

[0076] refer to Figure 4 , an example of a dual connectivity architecture 400 in which features of the present disclosure may be utilized represents a multi-radio dual connectivity (MR-DC) scenario.

[0077] MR-DC is a generalization of dual connectivity (DC) within E-UTRA, in which a UE with multiple receive / transmit (Rx / Tx) capabilities can be configured to utilize resources provided by two different nodes, which can be connected via a non-ideal backhaul, one node providing NR access and the other providing E-UTRA or NR access. One node acts as an MN and the other node acts as an SN. The MN and the SN are connected via a network interface, and at least the MN is coupled to the core network. The MN and / or the SN can operate using shared spectrum channel access. In addition, unless otherwise specified, all functions of the UE can be used for IAB-MT. Similar to that specified for the UE, the IAB-MT can access the network using one network node or using two different nodes with EN-DC and NR-DC architectures. In EN-DC, backhaul traffic over the E-UTRA radio interface is not supported.

[0078] Specifically, the dual connectivity architecture 400 is an example of E-UTRA-NR dual connectivity (EN-DC). E-UTRAN 401 supports MR-DC via EN-DC, where the UE ( Figure 44 (not shown) is coupled to one eNB 402(1) acting as a MN and one en-gNB 404(1) acting as a SN. The eNB 402(1) is coupled to the EPC 406 via an S1 interface 408 and to the en-gNB 404(1) via an X2 interface 410. The en-gNB 404(1) may also be coupled to the EPC 406 via an S1-U interface 412 and to other en-gNBs (e.g., en-gNB 404(2)) via an X2-U interface 414.

[0079] This feature may also be implemented in NG-RAN E-UTRA-NR dual connectivity (NGEN-DC), where the UE is coupled with one ng-eNB acting as MN and one gNB acting as SN. Additionally, this feature may also be implemented in NR-E-UTRA dual connectivity (NE-DC), where the UE is coupled with one gNB acting as MN and one ng-eNB acting as SN. Additionally, this feature may also be implemented in NR-NR dual connectivity (NR-DC), where the UE is coupled with one gNB acting as MN and another gNB acting as SN. Additionally, NR-DC may also be used when the UE is coupled with two gNB-DUs, one serving the MCG and the other serving the SCG, coupled with the same gNB-CU acting as both MN and SN. In some cases, the UE may be coupled with one base station with different cells, where one cell acts as the MN and the other acts as the SN.

[0080] refer to Figure 5 , the example of method 500 in which the SN notifies the MN before the CPC within the SN can be used to avoid simultaneous CPC and CHO.

[0081] At step 1: When SN 103 decides to perform CPC, SN 103 sends an SgNB Modify Request message including a CPC target PSCell list to MN 115. Including the CPC target PSCell list indicates to MN 115 that CPC will start.

[0082] If MN 115 does not have an ongoing CHO and agrees to CPC, for example, if one or more of the CPC target PSCell list is a suitable target, MN 115 may then perform one of two actions. If SN 103 includes CG-Config scg-CellGroupConfig in the SgNB Modify Request (e.g., included in an RRC Reconfiguration message to UE 104), MN 115 sends it to UE 104 in step 4. Alternatively, in step 6, MN 115 sends a SgNB Modify Confirm message to the SN.

[0083] Otherwise, MN 115 rejects SN 103 by sending SgNB Modification Reject and does not send an RRC reconfiguration message to UE 104. The MN decision on the applicability of CPC may be based on the shared configuration (UE baseband processing capability, UE band combination, UE power) or ongoing / planned CHO.

[0084] Optionally, the rejection may be a partial rejection, i.e., some PSCells are accepted and some are rejected. For each rejected PSCell, the MN 115 may indicate the reason, such as but not limited to CHO in progress, UE baseband processing capability limitation, UE band combination capability limitation, insufficient power or insufficient resources.

[0085] At step 7a, after CPC, SN 103 informs MN 115 that CPC is completed and UE 104 has selected PSCell by any of the following methods: Option A: a new message, referred to herein as SgNB modification completion message; or, Option B: an SN-initiated SN modification procedure, i.e., the PSCell change procedure defined in Section 10.6 of 3GPP TS 37.340.

[0086] Note that steps 2, 3, 5, 7, and 8-11 are not described for simplicity, but the signaling shown is included.

[0087] refer to Figure 6 , an example of method 600 of MN-initiated CPC cancellation may be performed by the MN in Figure 5 The CPC process is performed.

[0088] During CPC, MN 115 may urgently need CHO. In this case, MN 115 may request SN 103 to cancel (e.g., Figure 5 ) ongoing CPC.

[0089] For example, MN 115 may include a "CPC cancellation" indication in the SN modification request message. In response to the CPC cancellation indication, SN 103 will send an RRC reconfiguration to UE 104 to cancel the CPC. Thereafter, SN 103 sends an SN modification request confirmation to the MN, including the secondary cell group (SCG) configuration in the cell group configuration information element (CG-Config IE). When SN 103 receives the CPC cancellation indication, if the CPC is completed, the SCG configuration is a new configuration associated with the PSCell selected by the UE. Otherwise, it is the old SCG configuration before the CPC. In addition, SN 103 performs the CPC cancellation indication by sending an RRC reconfiguration message to UE 104 to remove the candidate PSCell.

[0090] refer to Figure 7-11In operation, the SN 103 may perform the method 800 of wireless communication, such as executing the CHO / CPC conflict component 105 via the processor 705 and / or the memory 710 .

[0091] At block 802, method 800 includes determining to perform a conditional primary SCG cell (PSCell) change (CPC) of a user equipment (UE) to one of a set of target primary SCG cells within an SN different from a current primary SCG cell. For example, in one aspect, SN 103, processor 705, memory 710, CHO / CPC conflict component 105, and / or determination component 720 may be configured to or may include a component for determining to perform a conditional primary SCG cell (PSCell) change (CPC) of a user equipment (UE) to one of a set of target primary SCG cells within an SN different from a current primary SCG cell.

[0092] At block 804, the method 800 includes generating a secondary cell modification message including identification information of a target primary SCG cell set of the CPC. For example, in one aspect, the SN 103, the processor 705, the memory 710, the CHO / CPC conflict component 105, and / or the generation component 725 may be configured to or may include means for generating a secondary cell modification message including identification information of a target primary SCG cell set of the CPC.

[0093] For example, the generating at block 804 may include generating the secondary cell modification message to further include a secondary cell group configuration message configured for transmission to the UE.

[0094] At block 806, the method 800 includes sending a secondary cell modification message including identification information of a target primary SCG cell set of the CPC to a master node (MN) associated with the UE. For example, in one aspect, the SN 103, the processor 705, the memory 710, the CHO / CPC conflict component 105, and / or the sending component 730 may be configured to or may include a component for sending a secondary cell modification message to a master node (MN) associated with the UE, the secondary cell modification message including identification information of a target primary SCG cell set of the CPC.

[0095] At block 808, the method 800 includes receiving a response message from the MN indicating confirmation or rejection of the secondary cell modification message. For example, in one aspect, the SN 103, the processor 705, the memory 710, the CHO / CPC conflict component 105, and / or the receiving component 735 may be configured to or may include means for receiving a response message from the MN indicating confirmation or rejection of the secondary cell modification message.

[0096] For example, the reception at block 808 may include receiving a modification confirmation message indicating confirmation of the secondary cell modification message, or receiving a modification rejection message indicating rejection of all or part of the secondary cell modification message. In addition, the modification rejection message may include a reason code indicating a rejection reason and / or information of a rejected cell, the information of the rejected cell identifying one or more cells in the target primary SCG cell set that are not suitable target primary SCG cells.

[0097] In optional terms, refer to Fig. 9 At block 902, the method 800 may further include receiving a CPC cancellation indication from the MN before the UE successfully accesses any one of the target primary SCG cell set. For example, in one aspect, the SN 103, the processor 705, the memory 710, the CHO / CPC conflict component 105, and / or the receiving component 735 may be configured to or may include a component for receiving a CPC cancellation indication from the MN before the UE successfully accesses any one of the target primary SCG cell set.

[0098] For example, the receiving at block 902 may include receiving a modification request including a CPC cancellation indication, and wherein sending a confirmation message includes sending a modification request confirmation message including a secondary cell group configuration in a cell group configuration information element.

[0099] In this optional aspect, at block 904, the method 800 may further include sending a message to the UE to cancel the CPC. For example, in one aspect, the SN 103, the processor 705, the memory 710, the CHO / CPC conflict component 105, and / or the sending component 730 may be configured to or may include means for sending a message to the UE to cancel the CPC.

[0100] In this optional aspect, at block 906, method 800 may further include sending a confirmation message to the MN to confirm the CPC cancellation indication. For example, in one aspect, SN 103, processor 705, memory 710, CHO / CPC conflict component 105, and / or sending component 730 may be configured to or may include means for sending a confirmation message to the MN to confirm the CPC cancellation indication.

[0101] refer to Fig.10 In an optional aspect, at block 1002, the method 800 may further include performing a random access procedure with a UE associated with one of the target primary SCG cell sets. For example, in one aspect, the SN 103, the processor 705, the memory 710, the CHO / CPC conflict component 105, and / or the RACH execution component 755 may be configured to or may include components for performing a random access procedure with a UE associated with one of the target primary SCG cell sets.

[0102] In this optional aspect, at box 1004, the method 800 may further include: after the UE successfully accesses the primary SCG cell selected by the UE from the target primary SCG cell set, indicating the CPC completion to the MN with a modification completion message or an SN modification request message, and including the UE-selected primary SCG cell identifier of the primary SCG cell selected by the UE from the target primary SCG cell set. For example, in one aspect, the SN 103, the processor 705, the memory 710, the CHO / CPC conflict component 105 and / or the indication component 760 may be configured to or may include a component for indicating the CPC completion to the MN with a modification completion message or an SN modification request message, and including the UE-selected primary SCG cell identifier of the primary SCG cell selected by the UE from the target primary SCG cell set after the UE successfully accesses the primary SCG cell selected by the UE from the target primary SCG cell set.

[0103] In optional terms, refer to Fig.11 At block 1102, the method 800 may further include performing a random access procedure with a UE associated with one of the target primary SCG cell sets. For example, in one aspect, the SN 103, the processor 705, the memory 710, the CHO / CPC conflict component 105, and / or the RACH execution component 755 may be configured to or may include components for performing a random access procedure with a UE associated with one of the target primary SCG cell sets.

[0104] In this optional aspect, at block 1104, the method 800 may further include performing a PSCell change procedure with the UE. For example, in one aspect, the SN 103, the processor 705, the memory 710, the CHO / CPC conflict component 105, and / or the cell change performing component 170 may be configured to or may include means for performing a PSCell change procedure with the UE.

[0105] refer to Figure 12-17 In operation, the MN 115 may perform the method 1300 of wireless communications, such as by executing the CPC / CHO conflict component 117 via the processor 1205 and / or the memory 1210 .

[0106] At block 1302, the method 1300 includes receiving a secondary cell modification message for a user equipment (UE) from a secondary node (SN), wherein the secondary cell modification message includes identification information of a target primary SCG cell set for a conditional primary SCG cell (PSCell) change (CPC) of the UE from a current primary SCG cell to a different primary SCG cell within the SN. For example, in one aspect, the MN 115, the processor 1205, the memory 1210, the CPC / CHO component 117, and / or the receiving component 1220 may be configured to or may include a component for receiving a secondary cell modification message for a user equipment (UE) from a secondary node (SN), wherein the secondary cell modification message includes identification information of a target primary SCG cell set for a conditional primary SCG cell (PSCell) change (CPC) of the UE from a current primary SCG cell to a different primary SCG cell within the SN.

[0107] At block 1304, the method 1300 includes determining whether the target primary SCG cell set is suitable for performing CPC. For example, in one aspect, the MN 115, the processor 1205, the memory 1210, the CPC / CHO component 117, and / or the determination component 1225 may be configured to or may include a component for determining whether the target primary SCG cell set is suitable for performing CPC.

[0108] At block 1306, the method 1300 includes sending a response message to the SN indicating confirmation or rejection of the secondary cell modification message. For example, in one aspect, the MN 115, the processor 1205, the memory 1210, the CPC / CHO conflict component 117, and / or the sending component 1230 may be configured to or may include means for sending a response message to the SN indicating confirmation or rejection of the secondary cell modification message.

[0109] For example, the sending at block 1306 may include the response message being a modification confirmation message indicating confirmation of the secondary cell modification message, or a modification rejection message indicating rejection of all or part of the secondary cell modification message. The modification rejection message may include a reason code indicating a rejection reason and / or information of a rejected cell, the information of the rejected cell identifying one or more cells in the target primary SCG cell set that are not suitable target primary SCG cells.

[0110] In an optional aspect, at block 1308, the method 1300 may further include receiving a secondary cell group configuration message associated with the target primary SCG cell set from the SN. For example, in one aspect, the MN 115, the processor 1205, the memory 1210, the CPC / CHO component 117, and / or the receiving component 1220 may be configured to or may include means for receiving a secondary cell group configuration message associated with the target primary SCG cell set from the SN.

[0111] In an optional aspect, at block 1310, the method 1300 may further include sending a secondary cell group configuration message to the UE. For example, in one aspect, the MN 115, the processor 1205, the memory 1210, the CPC / CHO component 117, and / or the sending component 1230 may be configured to or may include means for sending a secondary cell group configuration message to the UE.

[0112] In optional terms, refer to Fig.14 At block 1402, the method 1300 may further include determining to initiate a conditional handover (CHO) of the UE after sending a response message indicating the confirmation of the secondary cell modification message and before receiving a CPC completion indication from the SN. For example, in one aspect, the MN 115, the processor 1205, the memory 1210, the CPC / CHO component 117, and / or the determining component 1245 may be configured to or may include a component for determining to initiate a conditional handover (CHO) of the UE after sending a response message indicating the confirmation of the secondary cell modification message and before receiving a CPC completion indication from the SN.

[0113] In this optional aspect, at block 1404, the method 1300 may further include sending a CPC cancellation indication to the SN. For example, in one aspect, the MN 115, the processor 1205, the memory 1210, the CPC / CHO component 117, and / or the sending component 1230 may be configured to or may include means for sending a CPC cancellation indication to the SN.

[0114] Sending the CPC cancellation indication may include sending a modification request including the CPC cancellation indication, and wherein receiving the confirmation message includes receiving a modification request confirmation message including the secondary cell group configuration in the cell group configuration information element.

[0115] In this optional aspect, at block 1406, the method 1300 may further include receiving a confirmation message from the SN to confirm the CPC cancellation indication. For example, in one aspect, the MN 115, the processor 1205, the memory 1210, the CPC / CHO conflict component 117, and / or the receiving component 1220 may be configured to or may include means for receiving a confirmation message from the SN to confirm the CPC cancellation indication.

[0116] refer to Fig.15In an optional aspect, at block 1502, the method 1300 may further include: after sending the CPC cancellation indication to the SN, receiving a CPC initiation request in an SN modification request message from the SN. For example, in one aspect, the MN 115, the processor 1205, the memory 1210, the CPC / CHO component 117, and / or the receiving component 1220 may be configured to or may include a component for receiving a CPC initiation request in an SN modification request message from the SN after sending the CPC cancellation indication to the SN.

[0117] In this optional aspect, at block 1504, the method 1300 may further include rejecting the request by sending an SN modification rejection including a CPC cancellation indication. For example, in one aspect, the MN 115, the processor 1205, the memory 1210, the CPC / CHO component 117, and / or the rejection component 1265 may be configured to or may include means for rejecting the request by sending an SN modification rejection including a CPC cancellation indication.

[0118] refer to Fig.16 In another optional aspect, at block 1602, the method 1300 may further include receiving a handover preparation failure message in response to a handover request associated with the CHO. For example, in one aspect, the MN 115, the processor 1205, the memory 1210, the CPC / CHO component 117, and / or the receiving component 1220 may be configured to or may include means for receiving a handover preparation failure message in response to a handover request associated with the CHO.

[0119] In this optional aspect, at block 1604, the method 1300 may further include sending an SN modification request to the SN with an indication that the SN is enabled to re-initiate CPC. For example, in one aspect, the MN 115, the processor 1205, the memory 1210, the CPC / CHO component 117, and / or the sending component 1230 may be configured to or may include means for sending an SN modification request to the SN with an indication that the SN is enabled to re-initiate CPC.

[0120] refer to Fig.17 In an optional aspect, at block 1702, the method 1300 may further include receiving a modification completion message from the SN, the message including a primary SCG cell identifier of one of the target primary SCG cell set. For example, in one aspect, the MN 115, the processor 1205, the memory 1210, the CPC / CHO component 117, and / or the receiving component 1220 may be configured to or may include a component for receiving a modification completion message from the SN, the modification completion message including a primary SCG cell identifier of one of the target primary SCG cell set.

[0121] It should be understood that the specific order or hierarchy of blocks in the disclosed process / flowchart is an illustration of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of blocks in the process / flowchart can be rearranged. In addition, some blocks can be combined or omitted. The attached method claims present the elements of each block in an example order and are not meant to be limited to the specific order or hierarchy presented.

[0122] The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. For those skilled in the art, various modifications to these aspects will be apparent, and the general principles defined herein can be applied to other aspects. Therefore, the present claim is not intended to be limited to the various aspects shown herein, but to conform to the full scope consistent with the language claim, wherein, unless otherwise specified, the singular reference element is not intended to represent "one and only one", but to represent "one or more". The word "exemplary" is used here to represent "used as an example, instance or illustration". Any aspect described as "exemplary" herein is not necessarily interpreted as being superior to or superior to other aspects. Unless otherwise specified, the term "some" refers to one or more. Combinations such as "at least one of A, B or C", "one or more of A, B or C", "at least one of A, B and C", "one or more of A, B and C" and "A, B, C or any combination thereof" include any combination of A, B and / or C, and may include multiple A, multiple B, or multiple C. Specifically, combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, wherein any such combination may contain one or more members of A, B, or C. All structural and functional equivalents of the elements throughout the various aspects described in this disclosure that are known or later become known to one of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is expressly recited in the claims. The words "module," "mechanism," "element," "device," and the like are not intended to replace the word "component." Therefore, any claim element shall not be interpreted as a component plus function unless the element is expressly recited using the phrase "component for..."

[0123] Sample Clauses

[0124] A. A method for performing wireless communication at a user equipment (UE), comprising: determining to perform a conditional primary SCG cell (PSCell) change (CPC) of the user equipment (UE) to one of a target primary SCG cell set within an SN that is different from a current primary secondary cell group (SCG) cell; generating a secondary cell modification message including identification information of the target primary SCG cell set of the CPC; sending a secondary cell modification message including identification information of the target primary SCG cell set of the CPC to a master node (MN) associated with the UE; and receiving a response message from the MN indicating confirmation or rejection of the secondary cell modification message.

[0125] B. The method as described in paragraph A, wherein the secondary cell modification message further includes a secondary cell group configuration message configured to be sent to the UE.

[0126] C. The method as described in any one of paragraphs AB, wherein the response message includes a modification confirmation message indicating confirmation of the secondary cell modification message.

[0127] D. The method as described in any one of paragraphs AB, wherein the response message includes a modification rejection message indicating rejection of all or part of the secondary cell modification message.

[0128] E. The method of paragraph D, wherein the modified rejection message includes a reason code indicating a reason for the rejection.

[0129] F. A method as described in paragraph D, wherein the modified rejection message includes information of rejected cells, and the rejected cell information identifies one or more cells in the target master SCG cell set that are not suitable target master SCG cells.

[0130] G. As described in any of paragraphs AF, the method also includes: receiving a CPC cancellation indication from the MN before the UE successfully accesses any one of the target primary SCG cell sets; sending a message to the UE to cancel the CPC; and sending a confirmation message to the MN to confirm the CPC cancellation indication.

[0131] H. A method as described in paragraph G, wherein receiving a CPC cancellation indication includes: receiving a modification request including a CPC cancellation indication, and wherein sending a confirmation message includes sending a modification request confirmation message, the modification request confirmation message including a secondary cell group configuration in a cell group configuration information element.

[0132] I. A method as described in any one of paragraphs AH, the method also includes: performing a random access procedure with a UE associated with one of the target main SCG cell sets; and after the UE successfully accesses the main SCG cell selected by the UE from the target main SCG cell set, indicating the CPC completion to the MN with a modification completion message or an SN modification request message; and including the UE-selected main SCG cell identifier of the main SCG cell selected by the UE from the target main SCG cell set.

[0133] J. The method as described in any of paragraphs AI further includes: performing a random access procedure with a UE associated with one of the target primary SCG cell sets; and performing a PSCell change procedure with the UE.

[0134] K. A user device for wireless communication, comprising a memory storing computer-executable instructions; and at least one processor coupled to the memory and configured to execute the computer-executable instructions to perform the method of any one of claims AJ.

[0135] L. A user equipment for wireless communication, comprising components for performing the method of any one of claims AJ.

[0136] M. A non-transitory computer readable medium storing computer executable code which, when executed by a processor, causes the processor to perform the method of any one of claims AJ.

[0137] N. A method for performing wireless communication at a master node (MN), the method comprising: receiving a secondary cell modification message for a user equipment (UE) from a secondary node (SN), wherein the secondary cell modification message includes identification information of a target primary SCG cell (PSCell) set for a conditional PSCell change (CPC) of the UE from a current primary secondary cell group (SCG) cell to a different primary SCG cell within the SN; determining whether the target primary SCG cell set is suitable for performing CPC; and sending a response message to the SN indicating confirmation or rejection of the secondary cell modification message.

[0138] O. As described in paragraph N, the method also includes: receiving a secondary cell group configuration message associated with the target primary SCG cell set from the SN; and sending the secondary cell group configuration message to the UE.

[0139] P. The method as described in any one of paragraphs NO, further comprising: receiving a secondary cell group configuration message associated with a target primary SCG cell set from the SN; and sending the secondary cell group configuration message to the UE.

[0140] Q. A method as described in any of paragraphs NP, wherein the response message includes a modification confirmation message indicating confirmation of the secondary cell modification message.

[0141] R. The method as described in any of paragraphs NP, wherein the response message includes a modification rejection message indicating rejection of all or part of the secondary cell modification message.

[0142] S. The method of paragraph R, wherein the modified rejection message includes a reason code indicating a reason for the rejection.

[0143] T. The method as described in paragraph R, wherein the modified rejection message includes information of the rejected cell, and the information of the rejected cell identifies one or more cells in the target master SCG cell set that are not suitable target master SCG cells.

[0144] U. As described in any one of paragraphs NT, the method also includes: determining to initiate a conditional handover (CHO) of the UE after sending a response message indicating confirmation of the secondary cell modification message and before receiving a CPC completion indication from the SN; sending a CPC cancellation indication to the SN; and receiving a confirmation message from the SN confirming the CPC cancellation indication.

[0145] V. A method as described in paragraph U, wherein sending a CPC cancellation indication includes sending a modification request including a CPC cancellation indication, and wherein receiving a confirmation message includes receiving a modification request confirmation message, which modification request confirmation message includes a secondary cell group configuration in a cell group configuration information element.

[0146] W. As described in paragraph U, the method also includes: after sending a CPC cancellation indication to the SN, receiving a CPC start request in an SN modification request message from the SN; and rejecting the request by sending an SN modification rejection including the CPC cancellation indication.

[0147] X. As described in paragraph U, receiving a handover preparation failure message in response to a handover request associated with CHO; and sending an SN modification request with an indication allowing the SN to re-initiate CPC to the SN.

[0148] Y. As described in any one of paragraphs NX, the method also includes: receiving a modification completion message from the SN, the message including a master SCG cell identifier of one of the target master SCG cell sets.

[0149] Z. A base station for wireless communication, comprising a memory storing computer-executable instructions; and at least one processor coupled to the memory and configured to execute the computer-executable instructions to perform the method of any one of claims NY.

[0150] AA. A base station for wireless communication, comprising components for performing the method of any one of claims NY.

[0151] AB. A non-transitory computer readable medium storing computer executable code, which, when executed by a processor, causes the processor to perform the method of any one of claims NY.

Claims

1. A method for wireless communication at a secondary node SN, comprising: Determine a conditional primary SCG cell PSCell change CPC of the user equipment UE to one of the target primary SCG cell sets in the SN different from the current primary and secondary cell group SCG cell; Generate a secondary cell modification message including identification information of the target primary SCG cell set of CPC; Sending a secondary cell modification message including the identification information of the target primary SCG cell set of the CPC to a master node MN associated with the UE; receiving, from the MN, a response message indicating confirmation or rejection of the secondary cell modification message; Before the UE successfully accesses any one of the target primary SCG cell set, receiving a CPC cancellation indication from the MN; sending a message to the UE to cancel the CPC; and A confirmation message is sent to the MN to confirm the CPC cancellation indication. 2 . The method according to claim 1 , wherein the secondary cell modification message further comprises a secondary cell group configuration message configured to be sent to the UE. 3 . The method according to claim 1 , wherein the response message comprises a modification confirmation message indicating confirmation of the secondary cell modification message. 4 . The method according to claim 1 , wherein the response message comprises a modification rejection message indicating rejection of all or part of the secondary cell modification message.

5. The method of claim 4, wherein the modified rejection message includes a reason code indicating a reason for the rejection.

6. The method according to claim 4, wherein the modified rejection message includes information of rejected cells, and the information of the rejected cells identifies one or more cells in the target master SCG cell set that are not suitable target master SCG cells.

7. The method of claim 1 , wherein receiving a CPC cancellation indication comprises: A modification request including the CPC cancellation indication is received, and wherein sending a confirmation message includes sending a modification request confirmation message, the modification request confirmation message including the secondary cell group configuration in the cell group configuration information element.

8. The method according to claim 1, wherein the secondary cell modification message is a first secondary cell modification message, the target primary SCG cell set is a first target primary SCG cell set, the response message is a first response message, and the method further comprises: Sending a second secondary cell modification message to the MN associated with the UE, where the second secondary cell modification message includes identification information of a second target primary SCG cell set of the CPC; receiving, from the MN, a second response message indicating confirmation or rejection of the second secondary cell modification message; performing a random access procedure with a UE associated with one of the second target primary SCG cell sets; as well as After the UE successfully accesses the primary SCG cell selected by the UE from the second target primary SCG cell set, the CPC completion is indicated to the MN using a modification completion message or an SN modification request message, and includes the UE-selected primary SCG cell identifier of the primary SCG cell selected by the UE from the second target primary SCG cell set.

9. The method according to claim 1, wherein the secondary cell modification message is a first secondary cell modification message, the target primary SCG cell set is a first target primary SCG cell set, the response message is a first response message, and the method further comprises: Sending a second secondary cell modification message to the MN associated with the UE, where the second secondary cell modification message includes identification information of a second target primary SCG cell set of the CPC; receiving, from the MN, a second response message indicating confirmation or rejection of the second secondary cell modification message; performing a random access procedure with a UE associated with one of the second target primary SCG cell sets; as well as Perform a PSCell change procedure with the UE.

10. An apparatus for wireless communication at a secondary node SN, comprising: Memory; as well as a processor in communication with the memory and configured to: Determine a conditional primary SCG cell PSCell change CPC of the user equipment UE to one of the target primary SCG cell sets in the SN different from the current primary and secondary cell group SCG cell; Generate a secondary cell modification message including identification information of the target primary SCG cell set of CPC; Sending a secondary cell modification message including the identification information of the target primary SCG cell set of the CPC to a master node MN associated with the UE; receiving, from the MN, a response message indicating confirmation or rejection of the secondary cell modification message; Before the UE successfully accesses any one of the target primary SCG cell set, receiving a CPC cancellation indication from the MN; sending a message to the UE to cancel the CPC; and A confirmation message is sent to the MN to confirm the CPC cancellation indication. 11 . The apparatus according to claim 10 , wherein the secondary cell modification message further comprises a secondary cell group configuration message configured to be sent to the UE. 12 . The apparatus according to claim 10 , wherein the response message comprises a modification confirmation message indicating confirmation of the secondary cell modification message. 13 . The apparatus according to claim 10 , wherein the response message comprises a modification rejection message indicating rejection of all or part of the secondary cell modification message.

14. The apparatus of claim 10, wherein the processor is further configured to: performing a random access procedure with a UE associated with one of the target primary SCG cell sets; and Perform a PSCell change procedure with the UE.

15. A method for wireless communication at a master node MN, comprising: receiving a secondary cell modification message for a user equipment UE from a secondary node SN, wherein the secondary cell modification message includes identification information of a target primary SCG cell set for the UE to change CPC from a conditional primary SCG cell PSCell of a current primary secondary cell group SCG cell to a different primary SCG cell in the SN; Determine whether the target primary SCG cell set is suitable for performing CPC; Sending a response message to the SN indicating confirmation or rejection of the secondary cell modification message; Determine to initiate a conditional handover (CHO) of the UE after sending the response message indicating confirmation of the secondary cell modification message and before receiving a CPC completion indication from the SN; Sending a CPC cancellation indication to the SN; as well as A confirmation message is received from the SN to confirm the CPC cancellation indication.

16. The method according to claim 15, further comprising: receiving, from the SN, a secondary cell group configuration message associated with the target primary SCG cell set; as well as Sending the secondary cell group configuration message to the UE. 17 . The method according to claim 15 , wherein the response message comprises a modification confirmation message indicating confirmation of the secondary cell modification message. 18 . The method according to claim 15 , wherein the response message comprises a modification rejection message indicating rejection of all or part of the secondary cell modification message.

19. The method of claim 18, wherein the modified rejection message includes a reason code indicating a reason for the rejection.

20. The method of claim 18, wherein the modified rejection message includes information of rejected cells, the rejected cell information identifying one or more cells in the target master SCG cell set that are not suitable target master SCG cells.

21. The method of claim 15, wherein sending the CPC cancellation indication comprises: A modification request including the CPC cancellation indication is sent, and wherein receiving a confirmation message includes receiving a modification request confirmation message, the modification request confirmation message including the secondary cell group configuration in the cell group configuration information element.

22. The method of claim 15, further comprising: After sending the CPC cancellation indication to the SN, receiving a CPC initiation request in an SN modification request message from the SN; as well as The request is rejected by sending an SN Modification Reject including the CPC Cancel indication.

23. The method of claim 15, further comprising: receiving a handover preparation failure message in response to a handover request associated with the CHO; as well as An SN modification request is sent to the SN, wherein the SN modification request carries an indication allowing the SN to re-initiate the CPC.

24. The method of claim 15, further comprising: A modification completion message is received from the SN, wherein the modification completion message includes a primary SCG cell identifier of one of the target primary SCG cell set.

25. An apparatus for wireless communication at a master node MN, comprising: Memory; as well as a processor in communication with the memory and configured to: receiving a secondary cell modification message for a user equipment UE from a secondary node SN, wherein the secondary cell modification message includes identification information of a target primary SCG cell set for the UE to change CPC from a conditional primary SCG cell PSCell of a current primary secondary cell group SCG cell to a different primary SCG cell in the SN; Determine whether the target primary SCG cell set is suitable for performing CPC; Sending a response message indicating confirmation or rejection of the secondary cell modification message to the SN; Determine to initiate a conditional handover (CHO) of the UE after sending the response message indicating confirmation of the secondary cell modification message and before receiving a CPC completion indication from the SN; Sending a CPC cancellation indication to the SN; as well as A confirmation message is received from the SN to confirm the CPC cancellation indication.

26. The apparatus of claim 25, wherein the processor is further configured to: receiving, from the SN, a secondary cell group configuration message associated with the target primary SCG cell set; and Sending the secondary cell group configuration message to the UE.

27. An apparatus for wireless communication at a secondary node SN, comprising means for performing the method according to any one of claims 1-9.

28. A computer readable medium comprising stored instructions for wireless communication at a secondary node SN, which, when executed by a processor, causes the SN to perform a method according to any one of claims 1-9.

29. An apparatus for wireless communication at a master node MN, comprising means for performing the method according to any one of claims 15-24.

30. A computer readable medium comprising stored instructions for wireless communication at a master node MN, which when executed by a processor causes the MN to perform a method according to any one of claims 15-24.

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