Conditional procedure initiated by a Secondary Node (SN) for adding and changing SNs

Abstract

Various aspects of this disclosure relate to wireless communications, and more specifically, to procedures for supporting the addition and change of a Conditional New Radio (NR) Sub-Node (SN) using a Conditional Handover (CHO) procedure. Methods that can be performed by a User Equipment (UE) include: receiving configuration information from a Master Node (MN) that identifies a set of candidate cells for conditional addition or change of the SN for the UE based on execution criteria; detecting one of the candidate cells that satisfies the execution criteria; and taking action based on the detection to add or change the candidate cell to the SN.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Application No. 17 / 089,565, filed on November 4, 2020, which claims the benefit of and priority to U.S. Provisional Application No. 62 / 931,651, filed on November 6, 2019, which application is hereby assigned to the assignee of this application and is hereby expressly incorporated herein by reference in its entirety, as if fully set forth below, and for all applicable purposes. Technical Field

[0003] Aspects of the present disclosure relate to wireless communications, and more particularly, to procedures for supporting conditional New Radio (NR) secondary node (SN) addition and change by reusing a conditional handover (CHO) procedure. 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 can support communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). Examples of such multiple access technologies include Long Term Evolution (LTE) systems, 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] In some examples, a wireless multiple access communication system may include several base stations (BSs), each of which simultaneously supports communication for multiple communication devices (also referred to as user equipment (UE)). In an LTE or LTE-A network, a set of one or more BSs may define an eNodeB (eNB). In other examples (e.g., in a next generation or 5G network), a wireless multiple access communication system may include several distributed units (e.g., edge units (EUs), edge nodes (ENs), radio heads (RHs), smart radio heads (SRHs), transmit receive points (TRPs), etc.) communicating with several central units (CUs) (e.g., central nodes (CNs), access node controllers (ANs), etc.), wherein a set of one or more distributed units communicating with a central unit may define an access node (e.g., a new radio base station (NR BS), a new radio node B (NR NB), a network node, a 5G NB, a gNodeB (gNB), etc.). A BS or DU may communicate with a set of UEs on a downlink channel (e.g., for transmission from a BS or to a UE) and an uplink channel (e.g., for transmission from a UE to a BS or DU).

[0006] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at city, national, regional, and even global levels. An example of an emerging telecommunication standard is called New Radio (NR), for example, 5G radio access. It is designed to better support mobile broadband Internet access by improving spectrum efficiency, reducing costs, improving services, utilizing new spectrum, and using OFDMA with cyclic prefix (CP) on downlink (DL) and uplink (UL), as well as supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation (CA) to better integrate with other open standards.

[0007] However, as the demand for mobile broadband access continues to grow, there is a need for further improvements to NR technology. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies. Summary of the invention

[0008] The systems, methods, and devices of the present disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of the present disclosure as expressed by the claims that follow, some features will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled "Detailed Description," one will understand how the features of the present disclosure provide advantages including improved communications between access points and stations in a wireless network.

[0009] Certain aspects relate to a method for wireless communication by a secondary node (SN). The method generally includes: identifying a set of one or more candidate cells for conditional addition or change to a SN for a user equipment (UE) based on an execution criterion; and signaling information about the set of candidate cells to a primary node (MN).

[0010] Certain aspects relate to a method for wireless communication by a MN. The method generally includes: receiving a signaling from the SN that identifies a set of candidate cells for a UE to conditionally add or change to the SN based on execution criteria; and signaling configuration information about the set of candidate cells to the UE.

[0011] Certain aspects relate to a method for wireless communication by a UE. The method generally includes: receiving configuration information from a MN, the configuration information identifying a set of candidate cells for conditional addition or change to a SN and an execution criterion for the UE, wherein the execution criterion is obtained from the MN in a transparent container; detecting that one of the candidate cells satisfies the execution criterion; and taking action based on the detection to add or change the candidate cell to a SN.

[0012] Certain aspects relate to an apparatus for wireless communication by a SN, comprising: a memory and at least one processor coupled to the memory, the at least one processor being configured to: identify a set of one or more candidate cells for conditional addition or change of the SN for a UE based on execution criteria; and MN signaling information about the set of candidate cells.

[0013] Certain aspects relate to an apparatus for wireless communication by a MN, comprising: a memory and at least one processor coupled to the memory, the at least one processor being configured to: receive a signal notification from a SN, the signal notification identifying a set of candidate cells for conditional addition or change of the SN for a UE based on execution criteria; and signal configuration information about the set of candidate cells to the UE.

[0014] Certain aspects relate to an apparatus for wireless communication by a UE, comprising: a memory and at least one processor coupled to the memory, the at least one processor being configured to: receive configuration information from an MN, the configuration information identifying a set of candidate cells and execution criteria for conditional addition or change of a SN for the UE; detect that one of the candidate cells satisfies the execution criteria; and take action based on the detection to add or change the candidate cell to a SN.

[0015] Aspects generally include methods, apparatus, systems, computer-readable media, and processing systems as fully described herein with reference to and as illustrated by the accompanying figures.

[0016] To achieve the foregoing and related ends, one or more aspects 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. 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

[0017] In order to be able to understand in detail the manner in which the features of the present disclosure described above are used, a more particular description briefly summarized above may be obtained by reference to various aspects, some of which are illustrated in the accompanying drawings. It should be noted, however, that the drawings illustrate only certain typical aspects of the present disclosure and are therefore not to be considered as limiting the scope thereof, as the description may allow for other equally effective aspects.

[0018] Figure 1 is a block diagram conceptually illustrating an example telecommunications system in accordance with certain aspects of the present disclosure.

[0019] Figure 2 is a block diagram illustrating an example architecture of a distributed radio access network (RAN) in accordance with certain aspects of the present disclosure.

[0020] Figure 3 is a block diagram conceptually illustrating designs of example base stations (BSs) and user equipment (UEs) in accordance with certain aspects of the present disclosure.

[0021] Figure 4 and Figure 5 An example call flow diagram is shown for determining a handover (HO) configuration for a RAN HO procedure in accordance with certain aspects of the present disclosure.

[0022] Figure 6 Example operations for wireless communications by a master node (MN) are illustrated in accordance with certain aspects of the present disclosure.

[0023] Figure 7

[0013] Example operations for wireless communications by a UE are illustrated in accordance with certain aspects of the present disclosure.

[0024] Figure 8 Example operations for wireless communications by a secondary node (SN) are illustrated in accordance with certain aspects of the present disclosure.

[0025] Fig. 9 A first call flow diagram illustrating example communications between a UE, a MN, and a SN according to various aspects of the present disclosure.

[0026] Fig.10 A second call flow diagram illustrating example communications between a UE, a MN, and a SN according to various aspects of the present disclosure.

[0027] Fig.11 A communication device in accordance with aspects of the present disclosure is shown and may include various components configured to perform operations for the techniques disclosed herein.

[0028] Fig.12 A communication device in accordance with aspects of the present disclosure is shown and may include various components configured to perform operations for the techniques disclosed herein.

[0029] Fig.13 A communication device in accordance with aspects of the present disclosure is shown and may include various components configured to perform operations for the techniques disclosed herein.

[0030] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized on other aspects without specific recitation. DETAILED DESCRIPTION

[0031] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for supporting conditional (eg, new radio (NR)) secondary node (SN) addition and change by reusing a conditional handover (CHO) procedure.

[0032] Certain aspects of the present disclosure may be applied to New Radio (NR) (new radio access technology or 5G technology). NR may support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., above 80 MHz), millimeter wave (mmW) targeting high carrier frequency (e.g., 60 GHz), large-scale MTC (mMTC) targeting non-backward compatible MTC technology, and / or mission critical services targeting ultra-reliable low latency communication (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTIs) to meet corresponding quality of service (QoS) requirements. In addition, these services may coexist in the same subframe.

[0033] The following description provides examples, rather than limitations on the scope, applicability, or examples set forth in the claims. Without departing from the scope of the present disclosure, the functions and arrangements of the elements discussed may be changed. Various examples may omit, replace, or add various programs or components as appropriate. For example, the described method may be performed in a different order than described, and various steps may be added, omitted, or combined. Similarly, the features described with respect to some examples may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement a device or practice method. In addition, the scope of the present disclosure is intended to cover this device or method practiced using other structures, functionality, or structures and functionality other than or different from the various aspects of the present disclosure set forth herein. It should be understood that any aspect of the present disclosure disclosed herein may be embodied by one or more elements of the claims. The word "exemplary" used herein means "used as an example, instance, or illustration". Any aspect described as "exemplary" herein is not necessarily interpreted as being preferred or conducive to other aspects.

[0034] The technology described herein can be used in various wireless communication systems, such as long term evolution (LTE), code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA) and other systems. The terms "network" and "system" are often used interchangeably. A CDMA network can implement radio technologies such as Universal Terrestrial Radio Access (UTRA), CDMA2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. CDMA2000 covers IS-2000, IS-95 and / or IS-856 standards. A TDMA network can implement radio technologies such as Global System for Mobile Communications (GSM). An OFDMA network can implement radio technologies such as NR (e.g., 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). NR is an emerging wireless communication technology developed in conjunction with the 5G Technology Forum (5GTF). 3GPP LTE and Advanced LTE (LTE-A) are versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization named "3rd Generation Partnership Project (3GPP)". CDMA2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2 (3GPP2)". The techniques described herein can be used for the above-mentioned wireless networks and radio technologies, as well as other wireless networks and radio technologies. For clarity, although various aspects may be described herein using terms commonly associated with 3G and / or 4G wireless technologies, various aspects of the present disclosure may be applied to other communication systems based on generations, such as 5G and higher, including NR technologies.

[0035] Example Wireless Communication System

[0036] Figure 1 An example wireless communication network 100 is shown in which aspects of the present disclosure may be performed. For example, the wireless communication network 100 may be a new radio (NR) system (e.g., a 5G NR network). Figure 1As shown, user equipment (UE) 120a includes a handover manager 142, which can be configured to receive configuration information, which identifies a set of candidate cells for conditional addition or change of a secondary node (SN) for the UE based on an execution criterion. The handover manager 142 can also be configured to detect whether one of the candidate cells meets the execution criterion. If one of the candidate cells meets the execution criterion, the handover manager 142 can also be configured to perform adding or changing the candidate cell condition to the SN based on the detection.

[0037] Similarly, the base station (BS) 110a has a handover manager 144, which can be configured for handover operations. For example, if the BS 110a acts as an SN, the handover manager 144 can be configured to identify a set of candidate cells for adding or changing the conditions for the SN for the UE based on the execution criteria. The handover manager 144 can also be configured to signal the master node (MN) with configuration information about the set of candidate cells. In another example, if the BS 110a acts as an MN, the handover manager 144 can be configured to receive a signal notification from the SN, which signals the set of candidate cells for adding or changing the conditions for the SN for the UE based on the execution criteria. The handover manager 144 can also be configured to signal the UE with configuration information about the set of candidate cells.

[0038] like Figure 1 As shown, the wireless network 100 may include several BSs 110 and other network entities. A BS may be a station that communicates with a UE. Each BS 110 may provide communication coverage for a specific geographic area. In 3GPP, the term "cell" may refer to a coverage area of ​​a Node B and / or a Node B subsystem that serves the coverage area, depending on the context in which the term is used. In NR systems, the terms "cell" and gNB, Node B, 5G NB, AP, NR BS, NR BS or TRP may be interchangeable. In some examples, the cell is not necessarily stationary, and the geographic area of ​​the cell may move depending on the location of the mobile base station. In some examples, the base stations may be interconnected to each other and / or to one or more other base stations or network nodes (not shown) in the wireless communication network 100 by using various types of backhaul interfaces (such as direct physical connections, virtual networks, etc.) of any suitable transport network.

[0039] In general, any number of wireless networks can be deployed in a given geographic area. Each wireless network can support a specific radio access technology (RAT) and can operate on one or more frequencies. RAT can also be referred to as radio technology, air interface, etc. Frequency can also be referred to as carrier, channel, etc. Each frequency can support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks can be deployed.

[0040] A BS may provide communication coverage for macro cells, pico cells, femto cells, and / or other types of cells. A macro cell may cover a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access to UEs with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access to UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access to UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in a home, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In Figure 1 In the example shown in FIG. 1 , BSs 110a, 110b, and 110c may be macro BSs for macro cells 102a, 102b, and 102c, respectively. BS 110x may be a pico BS for pico cell 102x. BSs 110y and 110z may be femto BSs for femto cells 102y and 102z, respectively. A BS may support one or more (e.g., three) cells.

[0041] The wireless network 100 may also include a relay station. A relay station is a station that receives transmissions of data and / or other information from an upstream station (e.g., a BS or a UE) and sends transmissions of data and / or other information to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that relays transmissions for other UEs. Figure 1 In the example shown in , a relay station 110r may communicate with a BS 110a and a UE 120r to facilitate communication between the BS 110a and the UE 120r. A relay station may also be referred to as a relay BS, a relay, or the like.

[0042] The wireless network 100 may be a heterogeneous network including different types of BSs, such as macro BSs, pico BSs, femto BSs, relays, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different effects on interference in the wireless network 100. For example, a macro BS may have a high transmit power level (e.g., 20 watts), while a pico BS, a femto BS, and a relay may have a lower transmit power level (e.g., 1 watt).

[0043] Wireless network 100 may support synchronous operation or asynchronous operation. For synchronous operation, BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, BSs may have different frame timing, and transmissions from different BSs may not be aligned in time. The techniques described herein may be used for both synchronous and asynchronous operation.

[0044] A network controller 130 may be coupled to a set of BSs and provide coordination and control for these BSs. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with each other, directly or indirectly, for example, via a wireless backhaul or a wired backhaul.

[0045] UE 120 (e.g., 120x, 120y, etc.) may be distributed throughout the wireless network 100, and each UE may be stationary or mobile. UE may also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, customer premises equipment (CPE), cellular phone, smart phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, tablet computer, camera, gaming device, netbook, smartbook, ultrabook, medical device or medical equipment, biosensor / device, wearable device (such as smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet, etc.)), entertainment device (e.g., music device, video device, satellite radio, etc.), vehicle component or sensor, smart meter / sensor, industrial manufacturing equipment, global positioning system device, or any other suitable device configured to communicate via wireless or wired medium. Some UEs may be considered as evolved or machine type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location markers, etc., which can communicate with a BS, another device (e.g., a remote device), or some other entity. A wireless node can provide, for example, connectivity to or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. Some UEs can be considered Internet of Things (IoT) devices.

[0046] exist Figure 1 In FIG. 1 , a solid line with double arrows indicates desired transmissions between a UE and a serving BS, which is a BS designated to serve the UE on the downlink and / or uplink. A thin dashed line with double arrows indicates interfering transmissions between a UE and a BS.

[0047] Some wireless networks (e.g., LTE) use orthogonal frequency division multiplexing (OFDM) on the downlink and single carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM divide the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier can be modulated with data. In general, modulation symbols are sent in the frequency domain using OFDM and in the time domain using SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system bandwidth. For example, the spacing between subcarriers can be 15kHz, and the minimum resource allocation (called a "resource block" (RB)) can be 12 subcarriers (or 180kHz). Thus, for a system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), the nominal fast Fourier transform (FFT) size may be equal to 128, 256, 512, 1024, or 2048, respectively. The system bandwidth may also be partitioned into sub-bands. For example, a sub-band may cover 1.8 MHz (i.e., 6 resource blocks), and there may be 1, 2, 4, 8, or 16 sub-bands for a system bandwidth of 1.25, 2.5, 5, 10, or 20 MHz, respectively.

[0048] Although aspects of the examples described herein may be associated with LTE technology, aspects of the present disclosure may be applicable to other wireless communication systems, such as NR.

[0049] NR can utilize OFDM with CP on the uplink (UL) and downlink (DL), and includes support for half-duplex operation using time division duplex (TDD). A single component carrier bandwidth of 100MHz can be supported. NR resource blocks can span 12 subcarriers with a subcarrier bandwidth of 75kHz in a duration of 0.1 milliseconds (ms). Each radio frame with a length of 10ms can consist of 50 subframes. Therefore, each subframe can have a length of 0.2ms. Each subframe can indicate the link direction (e.g., DL or UL) used for data transmission, and the link direction for each subframe can be switched dynamically. Each subframe can include DL / UL data and DL / UL control data.

[0050] Beamforming can be supported, and the beam direction can be dynamically configured. Multiple-input multiple-output (MIMO) transmission with precoding can also be supported. The MIMO configuration in the DL can support up to 8 transmit antennas, with multi-layer DL transmission of up to 8 streams and up to 2 streams per UE. Multi-layer transmission of up to 2 streams per UE can be supported. Aggregation of multiple cells with up to 8 serving cells can be supported. Alternatively, NR can support different air interfaces other than OFDM-based air interfaces. The NR network may include entities such as CU and / or DU.

[0051] In some examples, access to the air interface may be scheduled, wherein a scheduling entity (e.g., BS) allocates resources for communications between some or all devices and equipment within its service area or cell. In the present disclosure, as further discussed below, a scheduling entity may be responsible for scheduling, allocating, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communications, subordinate entities utilize resources allocated by the scheduling entity. The BS is not the only entity that can act as a scheduling entity. That is, in some examples, a UE may act as a scheduling entity to schedule resources for one or more subordinate entities (e.g., one or more other UEs). In this example, the UE acts as a scheduling entity, and other UEs utilize resources scheduled by the UE for wireless communications. The UE may act as a scheduling entity in a peer-to-peer (P2P) network and / or a mesh network. In a mesh network example, in addition to communicating with a scheduling entity, UEs may optionally communicate directly with each other.

[0052] Therefore, in a wireless communication network having scheduled access to time-frequency resources and having a cellular configuration, a P2P configuration, and a mesh configuration, a scheduling entity and one or more subordinate entities may communicate using the scheduled resources.

[0053] As described above, a radio access network (RAN) may include a central unit (CU) and a distributed unit (DU). A NR BS (e.g., a gNB, a 5G Node B, a Node B, a transmit receive point (TRP), an access point (AP)) may correspond to one or more BSs. An NR cell may be configured as an access cell (ACell, A cell) or a data-only cell (DCell, D cell). For example, a RAN (e.g., a central unit or a distributed unit) may configure a cell. A DCell may be a cell used for carrier aggregation (CA) or dual connectivity, but not for initial access, cell selection / reselection, or switching. In some cases, a DCell may not send a synchronization signal--in some cases, a DCell may send a synchronization signal (SS). The NR BS may send a DL signal indicating a cell type to the UE. Based on the cell type indication, the UE may communicate with the NR BS. For example, the UE may determine the NR BS to be considered for cell selection, access, switching, and / or measurement based on the indicated cell type.

[0054] Figure 2 An example architecture of a distributed RAN 200 is shown, which may be Figure 1 The wireless communication network 100 shown in FIG. Figure 2 As shown, the distributed RAN includes a core network (CN) 202 and access nodes 208 (e.g., Figure 1 BS 110a).

[0055] The CN 202 may host core network functions. The CN 202 may be centrally deployed. The CN 202 functions may be offloaded (e.g., to Advanced Wireless Services (AWS)) to handle peak capacity. The CN 202 may include an access and mobility management function (AMF) 204 and a user plane function (UPF) 206. The AMF 204 and the UPF 206 may perform one or more of the core network functions.

[0056] AN 208 may communicate with CN 202 (e.g., via a backhaul interface). AN 208 may communicate with AMF 204 via an N2 (e.g., NG-C) interface. AN 208 may communicate with UPF 206 via an N3 (e.g., NG-U) interface. AN 208 may include a central unit-control plane (CU-CP) 210, one or more central units-user planes (CU-UP) 212, one or more DUs 214-218, and one or more antennas / remote radio units (AU / RRU) 220-224. CU and DU may also be referred to as gNB-CU and gNB-DU, respectively. One or more components of AN 208 may be implemented in gNB 226. AN 208 may communicate with one or more neighboring gNB / BSs.

[0057] The CU-CP 210 may be connected to one or more of the DUs 214-218. The CU-CP 210 and the DUs 214-218 may be connected via an F1-C interface. Figure 2 As shown, CU-CP 210 can be connected to multiple DUs, but a DU can be connected to only one CU-CP. Figure 2 Only one CU-UP 212 is shown, but AN 208 may include multiple CU-UPs. CU-CP 210 selects an appropriate CU-UP for a requested service (e.g., for UE 120a). CU-UP 212 may be connected to CU-CP 210. For example, DU-UP 212 and CU-CP 210 may be connected via an E1 interface. CU-CP 212 may be connected to one or more of DUs 214-218. CU-UP 212 and DUs 214-218 may be connected via an F1-U interface. Figure 2 As shown, the CU-CP 210 may be connected to multiple CU-UPs, but a CU-UP may be connected to only one CU-CP.

[0058] A DU (such as DU 214, 216 and / or 218) may host one or more TRPs (transmit / receive points, which may include edge nodes (ENs), edge units (EUs), radio heads (RHs), smart radio heads (SRHs), etc.). A DU may be located at the edge of a network with radio frequency (RF) capabilities. A DU may be connected to multiple CU-UPs, which are connected to (e.g., controlled by) the same CU-CP (e.g., for RAN sharing, radio as a service (RaaS), and service-specific deployments). A DU may be configured to provide services to a UE individually (e.g., dynamically selected) or jointly (e.g., joint transmission). Each of the DUs 214-216 may be connected to one of the AU / RRUs 220-224.

[0059] The CU-CP 210 may be connected to multiple DUs, which are connected to (e.g., controlled by) the same CU-UP 212. The connection between the CU-UP 212 and the DU may be established by the CU-CP 210. For example, the connection between the CU-UP 212 and the DU may be established using a bearer context management function. Data forwarding between the CU-UPs 212 may be via an Xn-U interface.

[0060] The distributed RAN 200 may support fronthaul solutions across different deployment types. For example, the RAN 200 architecture may be based on the transmission network capabilities (e.g., bandwidth, latency, and / or jitter). The distributed RAN 200 may share features and / or components with LTE. For example, the AN 208 may support dual connectivity with NR and may share a common fronthaul for LTE and NR. The distributed RAN 200 may enable collaboration between DUs 214-218, for example, via the CU-CP 212. Inter-DU interfaces may not be used.

[0061] Figure 3 A block diagram showing a design of a BS 110 and a UE 120, which may be Figure 1 For the restricted association scenario, BS 110 may be Figure 1 110c in the macro BS 110c, and the UE 120 may be the UE 120y. The BS 110 may also be Figure 1 and Figure 2 any other type of BS shown in FIG. 1 , and UE 120 may be Figure 1 BS 110 may be equipped with antennas 334a to 334t, processors 320, 330, 338 and / or controller / processor 340 of BS 110, which may be used to perform various techniques and methods described herein. For example, Figure 3 As shown, the controller / processor 340 of BS110 includes a handover manager 144 that can be configured for handover operations. For example, if BS110 acts as a SN, the handover manager 144 can be configured to identify a set of candidate cells for adding or changing the conditions for the SN for the UE based on the execution criteria. The handover manager 144 can also be configured to signal the MN with configuration information about the set of candidate cells. In another example, if BS 110a acts as a MN, the handover manager 144 can be configured to receive a signal notification from the SN, which signals the set of candidate cells for adding or changing the conditions for the SN for the UE based on the execution criteria. The handover manager 144 can also be configured to signal the UE with configuration information about the set of candidate cells.

[0062] Similarly, UE 120 includes a processor 380, which includes a handover manager 142 that can be configured to receive configuration information, and the configuration information identifies a set of candidate cells for conditional addition or change of a secondary node (SN) for the UE based on an execution criterion. The handover manager 142 can also be configured to detect whether one of the candidate cells meets the execution criterion. If one of the candidate cells meets the execution criterion, the handover manager 142 can also be configured to perform adding or changing the candidate cell condition to the SN based on the detection.

[0063] At BS 110, a transmit processor 320 may receive data from a data source 312 and control information from a controller / processor 340. The control information may be for a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical hybrid ARQ indicator channel (PHICH), a physical downlink control channel (PDCCH), etc. The data may be for a physical downlink shared channel (PDSCH), etc. The processor 320 may process (e.g., encode and symbol map) the data and the control information to obtain data symbols and control symbols, respectively. The processor 320 may also generate reference symbols, such as for a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a cell-specific reference signal (CRS). The transmit (TX) MIMO processor 330 may perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, and / or reference symbols (if applicable), and may provide an output symbol stream to modulators (MOD) 332a to 332t. Each modulator 332 may process a corresponding output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 332 may further process (eg, convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. The DL signals from modulators 332a through 332t may be transmitted via antennas 334a through 334t, respectively.

[0064] At UE 120, antennas 352a to 352r can receive downlink signals from BS 110 and can provide received signals to demodulators (DEMOD) 354a to 354r, respectively. Each demodulator 354 can adjust (e.g., filter, amplify, down-convert, and digitize) the corresponding received signal to obtain input samples. Each demodulator 354 can further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. MIMO detector 356 can obtain received symbols from all demodulators 354a to 354r, perform MIMO detection on the received symbols (if applicable), and provide detected symbols. Receive processor 358 can process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UE 120 to data sink 360, and provide decoded control information to controller / processor 380.

[0065] On the UL, at the UE 120, a transmit processor 364 may receive and process data from a data source 362 (e.g., for a physical uplink shared channel (PUSCH)) and control information from a controller / processor 380 (e.g., for a physical uplink control channel (PUCCH)). The transmit processor 364 may also generate reference symbols for reference signals. The symbols from the transmit processor 364 may be precoded by a TX MIMO processor 366 (if applicable), further processed by the demodulators 354a through 354r (e.g., for SC-FDM, etc.), and transmitted to the BS 110. At the BS 110, the UL signals from the UE 120 may be received by the antenna 334, processed by the modulator 332, detected by the MIMO detector 336 (if applicable), and further processed by the receive processor 338 to obtain decoded data and control information transmitted by the UE 120. The receive processor 338 may provide decoded data to a data sink 339 and decoded control information to a controller / processor 340 .

[0066] Controllers / processors 340 and 380 may direct the operation at BS 110 and UE 120, respectively. Memories 342 and 382 may store data and program codes for BS 110 and UE 120, respectively. Scheduler 344 may schedule UEs for data transmission on the DL and / or UL. Processor 340 and / or other processors and modules at BS 110 may perform or direct the execution of various processes for the techniques described herein, for example, Figure 6 and Figure 7 The processor 380 and / or other processors and modules at the UE 120 may also execute or direct, for example, Figure 8Execution of the functional blocks shown in .

[0067] Example switching scene

[0068] Some techniques and apparatus described herein provide low-latency or zero-latency handover from a source base station (BS) to a target BS (e.g., in a network such as a 4G / LTE or 5G / NR network). For example, some techniques and apparatus described herein provide configuration of handover using a first protocol stack of a user equipment (UE) and a second protocol stack of the UE, wherein the first protocol stack is used for communication with the first BS and the second protocol stack is used for communication with the second BS. The use of these two protocol stacks can enable configuration of handover with respect to the target BS while communication with the source BS is ongoing. Thus, the latency associated with handover of the UE from the source BS to the target BS is reduced. In addition, some techniques and apparatus described herein can provide buffering and backhaul of UE traffic between the source BS and the target BS so that the traffic flow to the UE is not interrupted (or to reduce or minimize the interruption), thereby further reducing the latency associated with handover of the UE. In this way, in the case of handover of the UE, the service level at the UE can be met, which allows performance requirements for certain types of services (e.g., gaming services, multimedia services, high reliability services, low latency services, etc.) to be met.

[0069] In addition, some techniques and apparatuses described herein may provide a common packet data convergence protocol (PDCP) function for a make-before-break (MBB) handover procedure, which may streamline security key management, encryption / decryption, integrity protection, integrity verification, data unit reordering / duplicate discarding, link selection logic, etc. Some techniques and apparatuses described herein provide control plane (e.g., BS, network controller, control entity, etc.) messaging and processing to support MBB handover. Some techniques and apparatuses described herein provide MBB handover using carrier aggregation (CA) multiple input multiple output (MIMO) technology, wherein a weakened MIMO configuration is signaled to make at least one antenna available for MBB handover. In addition, some techniques and apparatuses described herein provide a role-switching-based MBB handover technique, wherein the primary cell group of the UE is switched from the source base station to the target base station while the connection with the source base station and the target base station is active. In this way, low-latency or zero-latency handover (and the advantages described above in conjunction with low-latency or zero-latency handover) is achieved.

[0070] Figure 4 4 is a call flow diagram illustrating an example 400 of determining a handover configuration for a handover procedure of a radio access network (RAN) according to various aspects of the present disclosure. Figure 4As shown, UE 120 is handed over from source BS 110-1 to target BS 110-2. UE 120 may be Figure 1 1 and the target BS 110-2 may be implemented by any UE (e.g., UE 120a) of Figure 1 Any BS 110 (e.g., BS 110a) or Figure 2 any BS 110 (e.g., AN 208), Figure 4 DU 214-248 or Figure 4 DU 214-218 is implemented by the TRP hosted by Figure 4 The described switching may be intra-frequency or inter-frequency, and / or may be intra-CU or inter-CU.

[0071] like Figure 4 As shown, at 405, UE 120 may establish a wireless communication connection (hereinafter referred to as a source connection) with source BS 110-1. At 410, UE 120 may indicate the capabilities of UE 120 to any one or more of source BS 110-1, target BS 110-2, or another network entity, such as AMF (e.g., Figure 2 AMF 204), UPF (e.g. Figure 2 For example, at 410, UE 120 may indicate that UE 120 has simultaneous transmit and receive capability and / or dual connectivity capability.

[0072] At 415, UE 120 may provide a measurement report to source BS 110-1. The measurement report may be generated by UE 120 and may indicate to source BS 110-1 that a handover from source BS 110-1 to target BS 110-2 is to be performed. For example, UE 120 may perform a cell quality measurement (e.g., an L3 cell quality measurement) to evaluate the quality of a radio link between UE 120 and one or more of source BS 110-1 and target BS 110-2. Accordingly, the measurement report may include a result of the cell quality measurement. In some examples, if the quality of the radio link between UE 120 and source BS 110-1 is sufficient to allow successful UL communication of the measurement report, successful reception of the measurement report at source BS 110-1 may indicate to source BS 110-1 that a handover from source BS 110-1 to target BS 110-2 is to be performed.

[0073] At 420 (assuming successful reception of the measurement report at 415), source BS 110-1 may determine a configuration for a handover procedure based at least in part on the capabilities indicated at step 2. For example, source BS 110-1 may provide a handover request to target BS 110-2 and may receive a handover confirmation (ACK) from target BS 110-2. In some aspects, source BS 110-1 may communicate with target BS 110-2 to determine a handover configuration for UE 120.

[0074] At 425, source BS 110-1 may provide a configuration for a handover procedure to UE 120. For example, the handover configuration may include a configuration for a handover procedure that utilizes or does not utilize the indicated capabilities of UE 120. In some aspects, the handover configuration may indicate that a make-before-break (MBB) handover procedure and / or a DC-based MBB handover procedure may be performed. Thus, the configuration may indicate to UE 120 whether to maintain a radio link connection to source BS 110-1 while and / or after establishing a radio link connection to target BS 110-2.

[0075] At 430, UE 120 requests a connection with target BS 110-2 (eg, using the configuration received from source BS 110-1). For example, UE 120 may perform a random access procedure to establish a connection with target BS 110-2 (hereinafter referred to as a target connection).

[0076] In response, at 435, the target BS 110-2 may reply with an acknowledgment. Then at 440, the UE 120 and the target BS 110-2 may establish a target connection. Figure 4 As apparent from the example 400 shown in FIG. 4 , during the handover process, UE 120 may simultaneously maintain a source connection with both source BS 110-1 and target BS 110-2. In this case, since UE 120 maintains active connections with both source BS 110-1 and target BS 110-2 for a period of time, UE 120 may experience reduced latency and / or minimal data interruption time (e.g., 0 ms handover) relative to previous techniques.

[0077] At 445, target BS 110-2 may instruct UE 120 to release the source connection between UE 120 and source BS 110-1 to complete the handover. For example, once UE 120 and / or target BS 110-2 determine that the target connection is sufficiently strong (e.g., a communication parameter measured by UE 120 and / or target BS 110-2 satisfies a first threshold indicating a strong connection), target BS 110-2 may send an instruction to complete the handover.

[0078] In some aspects, the release of the source connection may not be based on an instruction from the target BS 110-2. Instead, the UE 120 may release the source connection based at least in part on the establishment of the target connection without an instruction from the target BS 110-2 (e.g., the UE 120 determines that the communication parameters measured by the UE 120 meet the first threshold indicating a strong target connection). In some aspects, the UE 120 may release the source connection based on an instruction from the source BS 110-1. In this example, the instruction may be based at least in part on receiving by the source BS 110-1 an indication of the establishment of the target connection from the target BS 110-2 or from the UE 120.

[0079] At 450, UE 120 may release the source connection to source BS 110-1. At 455, additional communications between the UE and target BS 110-2 may occur using the target connection.

[0080] Accordingly, if Figure 4 As shown in example 400 in FIG. 4 , the UE may provide the capability to the BS or network entity, and the BS may configure the MBB switching procedure for the UE to enable the UE to use the capability during the handover procedure. Therefore, the UE may achieve enhanced performance during the handover procedure and may experience minimal mobility interruption time (e.g., via 0 ms handover) relative to a handover procedure that does not consider or utilize the UE's capability.

[0081] As indicated above, Figure 4 are provided as examples. Other examples can be found in the Figure 4 The examples described are different.

[0082] Figure 5 is a call flow diagram illustrating an example 500 of determining a handover configuration for a handover procedure of a RAN according to various aspects of the present disclosure. More specifically, Figure 5 An example of an intra-CU handover procedure using enhanced MBB handover is shown in which both the source BS 110 - 1 and the target BS 110 - 2 are associated with the same CU 502 .

[0083] Before the call session begins, UE 120 may exchange user data (eg, UL user data from UE 120 via PUSCH and / or DL ​​user data received by UE 120 via PDSCH) with CU 502 via source BS 110-1. At 505, UE 120 may send a measurement report to source BS 110-1.

[0084] Figure 5 The generation and sending of measurement reports may include Figure 4Features of the measurement report described in . In some aspects, UE 120 may generate and send a measurement report based at least in part on an event trigger associated with determining a handover procedure to be initiated (e.g., a signal measurement that meets a threshold). For example, the execution criteria for conditional SN addition may involve an inter-RAT measurement event, which is configured to indicate whether one or more of the following is true: (i) a measured signal quality value of at least one inter-RAT neighbor is greater than a first threshold (e.g., the signal is strong enough), or (ii) a measured signal quality value of a P cell (PCell) is less than a first threshold, and a measured signal quality value of at least one inter-RAT neighbor (e.g., another BS or PCell at the current BS) is greater than a second threshold.

[0085] In some examples, UE 120 may include simultaneous transmission and reception capabilities (e.g., MBB capabilities) that allow UE 120 to simultaneously transmit and receive data and / or information during handover. In this case, UE 120 may establish and maintain multiple connections with multiple different BSs (e.g., with source BS 110-1 and target BS 110-2).

[0086] At 510, source BS 110-1 may send a UL radio resource control (RRC) transfer to CU 502. In some aspects, the UL RRC transfer may include a measurement report. In additional aspects, the UL RRC transfer may enable CU 502 to determine a handover configuration to be used for a handover procedure for UE 120. For example, CU 502 may select from possible handover procedures that may be performed by UE 120 based at least in part on the indicated capabilities of UE 120. In some aspects, CU 502 may select an enhanced MBB handover procedure for UE 120 based at least in part on the simultaneous transmit and receive capabilities indicated by UE 120.

[0087] CU 502 may send a UE context setup request to target BS 110-2 at 515. In some examples, CU 502 may send the UE context setup request to, in part, indicate to target BS 110-2 that UE 120 will be handed over to target BS 110-2 during a handover procedure.

[0088] Target BS 110-2 may respond to the UE context setup request by sending a UE context setup response at 520. Target BS 110-2 may send the UE context setup response to acknowledge the request and / or to indicate a capability to support the handover procedure and to serve UE 120 after the handover procedure.

[0089] At 525, CU 502 may send a DL RRC transfer to source BS 110-1. In some aspects, the DL RRC transfer may include an RRC reconfiguration message indicating a configuration for a handover procedure in which UE 120 is to be handed over from source BS 110-1 to target BS 110-2.

[0090] At 530, source BS 110-1 sends an RRC reconfiguration to UE 120. In some aspects, the RRC reconfiguration may include information identifying target BS 110-2, information identifying a handover configuration, and / or any other suitable information. In some examples, the RRC reconfiguration may include information indicating that UE 120 is to perform an enhanced MBB handover procedure with target BS 110-2 using the simultaneous transmit and receive capabilities of UE 120. In this case, UE 120 may determine that it can maintain a connection with source BS 110-1 while establishing a connection with target BS 110-2.

[0091] At 535, UE 120 may perform a random access procedure with target BS 110-2 (e.g., to initiate and / or establish a connection with target BS 110-2). In some aspects, UE 120 may continue to exchange user data (e.g., uplink user data and / or downlink user data) with CU 502 via source BS 110-1 during and after the random access procedure.

[0092] At 540, UE 120 may send an RRC reconfiguration complete message to target BS 110-2. In some aspects, UE 120 may use a dual protocol stack including a source protocol stack for communicating with source BS 110-1 and a target protocol stack for communicating with target BS 110-2. Each of these protocol stacks may include a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, a medium access control (MAC) layer, and / or a physical (PHY) layer. In some aspects, the source protocol stack and the target protocol stack may share one or more layers, such as a common PDCP layer or entity. In some aspects, UE 120 may use a target protocol stack for UL data transmission.

[0093] At 545, the target BS 110-2 may send an UL RRC transfer to the CU 502. In some examples, the UL RRC transfer may indicate that the RRC reconfiguration is complete. Accordingly, in some aspects, based at least in part on receiving an indication that the RRC reconfiguration is complete, the CU 502 may determine that the handover is complete. For example, when a completion determination is made, the CU 502 may utilize and / or configure one or more thresholds for one or more measurement parameters to perform a handover completion procedure (e.g., to release the source BS 110-1). In addition, in some aspects, after the RRC reconfiguration is complete, the UE 120 may perform uplink user / control plane replication with the source BS 110-1 and the CU 502. For example, control plane data may be replicated and shared between the BS 110-1 and the CU 502. Furthermore, in some aspects, after CU 502 determines that RRC reconfiguration is complete, CU 502 may send DL user data to UE 120 via target BS 110-2 while also continuing to send DL user / control plane replication to UE 120 via source BS 110-1. Accordingly, UE 120 may achieve improved reliability when receiving data on the downlink.

[0094] At 550, CU 502 may send a UE context modification request to source BS 110-1. The UE context modification request may include sending a stop indicator to indicate that source BS 110-1 is to be released from serving UE 120 (e.g., release of a radio link between source BS 110-1 and UE 120). In some examples, source BS 110-1 may provide CU 502 with a DL data delivery status indicating a status of DL user / control plane replication that source BS 110-1 is communicating to UE 120.

[0095] At 555, source BS 110-1 may send a UE context modification response to CU 502. For example, the UE context modification response may include a confirmation that source BS 110-1 is to be released and / or no longer serve UE 120 during the handover procedure.

[0096] At 560, CU 502 may send a DL RRC transfer to target BS 110-2. The DL RRC transfer may include an RRC reconfiguration message indicating that a handover procedure is to be performed from source BS 110-1 to target BS 110-2.

[0097] At 565, target BS 110-2 may send an RRC reconfiguration to UE 120. In some examples, the RRC reconfiguration message may indicate that UE 120 is to release the connection with source BS 110-1. Thus, UE 120 may release the connection with source BS 110-1 based at least in part on receiving the RRC reconfiguration message. In addition, UE 120 may then begin exchanging uplink user data and downlink user data with CU 502 via target BS 110-2.

[0098] UE 120 may send an RRC reconfiguration complete message to target BS 110-2 at 570. The RRC reconfiguration complete message may indicate that UE 120 has released the connection with source BS 110-1.

[0099] At 575, the target BS 110-2 may send a UL RRC transfer to the CU 502. In some aspects, the UL RRC transfer may be performed in response to receiving an RRC reconfiguration complete message, and may indicate receipt of the RRC reconfiguration complete message from the UE 120.

[0100] At 580, CU 502 may then send a UE context release command to source BS 110-1 (eg, so that source BS 110-1 does not continue to attempt to serve UE 120).

[0101] At 585, source BS 110-1 may send a UE context release complete message to CU 502. The UE context release complete message may be a confirmation that source BS 110-1 is no longer communicating with and / or serving UE 120.

[0102] As indicated above, Figure 5 are provided as examples. Other examples can be found in the Figure 5 The examples described are different.

[0103] Example Optimization of an Enhanced Handover (HO) Procedure Using Aspects of Conditional Handover (CHO)

[0104] Aspects of the present disclosure relate to wireless communications, and more particularly, to an enhanced handover (HO) procedure configured to improve make-before-break (MBB) and conditional handover (CHO) procedures. In some cases, the optimization may support MBB and / or CHO procedures involving N2 signaling. In some cases, the optimization may include taking actions to prioritize handover procedures to a target base station (BS) that may be able to utilize an Xn connection.

[0105] N2 signaling generally refers to signaling via the physical N2 interface between the NG-RAN gNodeB (gNB) and the access and mobility management function (AMF) in the 5G Core (5GC) network, and the logical N1 interface between the user equipment (UE) and the AMF. N2 is generally used as a control plane interface between the access network (NG-RAN or non-3GPP wireless local area network (WLAN)) and the 5GC network. N2 generally involves connection management, UE context and protocol data unit (PDU) session management, and UE mobility management. Xn signaling generally refers to signaling using the Xn interface that exists between base stations (e.g., between gNBs). Xn generally refers to the network interface between NG-RAN nodes.

[0106] The techniques presented herein can help provide optimizations to support MBB and CHO for inter-NG RAN handover.

[0107] In some cases of enhanced handover procedures, the source BS and the target BS are connected via Xn, which provides a relatively low-latency communication interface. In this case, data forwarding can be communicated between these nodes via Xn. Therefore, aspects of the present disclosure can allow N2-based HO procedures to prioritize such nodes to take advantage of the lower latency associated with Xn signaling.

[0108] Typically, the CHO configuration is sent to the UE before the actual HO event. The source BS may prepare one or more candidate target cells for CHO. For each candidate target cell, the network (e.g., source BS and / or CN) configures information to the UE to allow the UE to connect to the target cell during HO, and configures conditions to trigger HO to the target cell. When the HO conditions are met, the UE initiates a random access procedure (RACH) with the target cell. In this case, the UE does not need to send measurement reports or wait for RRC reconfiguration to perform HO.

[0109] As described above, in a CHO procedure defined for N2-based candidate cell preparation, the source BS may prepare and / or select candidate cells based solely on measurement criteria. If some cells belong to different AMFs, it may be beneficial to optimize the source BS and UE CHO execution logic to prioritize cells using the same AMF. In some cases, data forwarding over N2 may benefit from optimizations regarding when to enable data forwarding for MBB and / or CHO handover procedures.

[0110] Conditional procedure initiated by a Secondary Node (SN) for adding and changing SNs

[0111] Aspects of the present disclosure provide techniques that may help optimize / improve enhanced handover (HO) procedures, such as make-before-break (MBB) and conditional handover (CHO).

[0112] As discussed, CHO is a HO procedure in which a user equipment (UE) selects a target cell for HO from candidate target cells based on CHO execution criteria. As described herein, the CHO procedure may be implemented for a secondary node (SN) addition or change procedure, and may reduce the delay involved in SN addition or change in a dual connectivity scenario.

[0113] For conditional primary and secondary cell (PSCell, PS cell) changes, various scenarios for SN changes may include SN changes initiated by the master node (MN) and SN changes initiated by the SN. As the name implies, in an SN change initiated by the MN, typically, in addition to deciding which PSCells can be configured as candidate PSCells, the MN also determines execution criteria and performs an SN addition procedure with the candidate SNs. Alternatively, in an SN change initiated by the SN, typically, the SN decides which PSCells can be configured as candidate PSCells and performs an SN addition procedure with the candidate SNs. In some cases, an SN change initiated by the SN may involve the SN determining execution criteria.

[0114] Figure 6 , Figure 7 and Figure 8 It is shown that the BSs (eg, Figure 1 , Figure 2 or Figure 3 ), a BS acting as a MN (e.g., Figure 1 , Figure 2 or Figure 3 any type of BS shown in ) and UE (e.g., Figure 1 or Figure 3 Flowchart of example operations for an SN initiated SN change procedure performed by a UE of any type shown in FIG.

[0115] Figure 6 600 that may be performed by a secondary node (SN) in accordance with certain aspects of the present disclosure. For example, operations 600 may be performed by a BS (e.g., Figure 1 , Figure 2 or Figure 3 Operation 600 may be performed by BS 110 as shown in FIG. Figure 7 and Figure 8 The operations 700 performed by the MN and / or the operations 800 performed by the UE as discussed above are in addition to the operations 700 performed by the MN and / or the operations 800 performed by the UE. Operation 600 may be implemented as a processor (e.g., Figure 3 In addition, for example, via one or more antennas (e.g., Figure 3The antenna 334 of the SN may enable the transmission and reception of signals by the SN in operation 600. In some aspects, the transmission and reception of signals by the SN may be implemented via a bus interface of one or more processors (e.g., controller / processor 340) that obtain and / or output signals.

[0116] Operations 600 begin at block 602 by the SN identifying, for a UE, a set of one or more candidate cells for conditional addition or change of the SN based on execution criteria. At block 604, the SN signals information about the set of candidate cells to the MN.

[0117] Figure 7 700 are illustrated as example operations that may be performed by a master node (MN) in accordance with certain aspects of the present disclosure. Operations 700 may be performed, for example, by a BS (e.g., Figure 1 , Figure 2 or Figure 3 BS 110 or Figure 3 Operation 700 may be performed by one or more processors as shown in FIG. Figure 6 and Figure 8 The operations 600 performed by the SN and / or the operations 800 performed by the UE as discussed above are in addition to the operations 600 performed by the SN and / or the operations 800 performed by the UE. Operation 700 may be implemented as a processor (e.g., Figure 3 In addition, for example, via one or more antennas (e.g., Figure 3 The antenna 334 of the MN may enable the transmission and reception of signals by the MN in operation 700. In some aspects, the transmission and reception of signals by the MN may be implemented via a bus interface of one or more processors (e.g., controller / processor 340) that obtain and / or output signals.

[0118] Operations 700 may begin at block 702 by receiving a signaling from the SN that identifies a set of candidate cells for conditional addition or change of the SN for the UE based on execution criteria. At block 604, the MN signals configuration information about the set of candidate cells to the UE.

[0119] Figure 8 800 is shown as an example operation that may be performed by a UE in accordance with certain aspects of the present disclosure. Operations 800 may be performed, for example, by a UE (such as a Figure 1 and Figure 3 UE 120 shown in (or Figure 3 Operation 800 may be performed by one or more processors as shown in FIG. Figure 6 and Figure 7The operations 600 discussed above are performed by the SN and / or by the MN. The operations 800 may be implemented as a processor (e.g., Figure 3 In addition, for example, via one or more antennas (e.g., Figure 3 The antenna 352 of the UE may enable the transmission and reception of signals by the UE in operation 800. In certain aspects, the transmission and reception of signals by the UE may be implemented via a bus interface of one or more processors (e.g., controller / processor 380) that obtain and / or output signals.

[0120] Operations 800 may begin at block 802 by the UE receiving configuration information from the MN that identifies a set of candidate cells for conditional addition or change of the SN for the UE based on an execution criterion. At block 804, the UE detects that one of the candidate cells satisfies the execution criterion. At block 806, the UE takes action based on the detection to add or change the candidate cell to the SN.

[0121] As discussed above, the UE 120 may be configured with conditional PSCell execution criteria for SN add and change procedures. The measurement events used to trigger PSCell add and / or PSCell change may differ based on the type of dual connectivity architecture. In addition, the measurement events may be independently configured by the MN 110a and the SN. Therefore, the conditional PSCell add / change RRC message must support configuration of separate execution criteria for each of the multiple PSCells to allow the UE 120 to perform PSCell add and / or PSCell change.

[0122] For conditional PSCell addition and / or change, there are various options for supporting SN initiated SN change. In some aspects, for SN change triggered by SN, the SN may identify a set of one or more PSCells that may be configured as candidate cells, and the MN determines execution criteria for the candidate cells. In some aspects, for SN change triggered by SN, the SN may perform both of identifying a set of one or more PSCells that may be configured as candidate cells, and determining execution criteria for the candidate cells.

[0123] Fig. 9 A first call flow diagram 900 is shown illustrating example communications between a UE, a MN, and a SN according to various aspects of the present disclosure. Fig. 9As shown in the first option, the SN may identify a set of one or more PSCells that may be configured as candidate cells, and the MN determines execution criteria for the candidate cells. Upon determining a triggering event, the UE 120 may determine to fall back to a call with the SN 110a (e.g., Figure 1 For example, the triggering event may include detection of a HO failure (e.g., T304 expiration) or a radio link failure (RLF) on the SN connection by the UE 120 while the UE 120 is still connected to the SN 110a (e.g., the source cell is active). In this example, the UE 120 may declare an RLF on the SN connection and operate using the existing SN 110a connection but avoid triggering a radio resource control (RRC) reestablishment.

[0124] Before and during a triggering event, UE 120 may monitor neighboring cells. Fig. 9 In the example of , the neighboring cells may include a first candidate secondary node (CSN1) and a second candidate secondary node (CSN2) (e.g., BS 110c and BS 110d, respectively). In response to the triggering event, UE 120 may send a measurement report identifying CSN1 and CSN2 to MN 110b configured for measurement at step 1. Subsequently, MN 110b may forward the measurement report to SN 110a. The measurement report may be generated by UE 120 and may indicate to MN 110b and SN 110a that UE 120 is requesting CHO to a new or additional SN.

[0125] Based on the received measurement reports, the SN may decide which of the candidate cells to configure as the new PSCell for UE 120 (e.g., CSN1 and CSN2 in this example). After identifying the set of candidate cells for the SN list, SN 110a may initiate a conditional SN change by sending a candidate SN addition list including both CSN1 and CSN2 to MN 110b in an XN message at step 2.

[0126] As shown, MN 110b may perform an SN add procedure with the candidate SN. In step 3, MN 110b may send a first conditional SN add message (e.g., an SN add request to CSN1) to initiate the first conditional SN add procedure with CSN1. In step 4, MN 110b may receive an SN add confirmation sent by CSN1.

[0127] In step 5, MN 110b may send a second conditional SN add message (eg, SN add request to CSN2) to initiate the second conditional SN add procedure with CSN2. In step 6, MN 110b may receive an SN add confirm sent by CSN2.

[0128] The MN 110b may also determine execution criteria for each candidate SN, wherein the execution criteria provide criteria according to which execution of the addition or change (eg, HO) of a particular one of CSN1 110b or CSN2 110c is to be performed.

[0129] In certain aspects, the UE 120, MN 110b, and SN 110a may support use of the A3 / A5 event execution criteria for conditional NR PSCell addition execution conditions.

[0130] In step 7, MN 100b may send an execution condition (e.g., execution criteria) and a candidate SN list to UE 120 in an RRC configuration message (e.g., an "RRC reconfiguration message" for NR) to UE 120. In some examples, the RRC configuration message may configure UE 120 for multiple candidate SNs in a single message. For example, the RRC configuration message may include configuration information for both CSN1 and CSN2. In some examples, the RRC configuration message may include one or more of the following: (i) source cell RRC configuration change (if any), (ii) conditional SN addition or change execution criteria (configured by MN 110b) for each candidate cell in the set, and / or (iii) RRC reconfiguration for each CSN.

[0131] After receiving the RRC configuration message, UE 120 may monitor the conditions for changing the PSCell based on the configuration received from the MN.

[0132] For example, UE 120 may determine whether the quality of the neighbor cell is greater than a threshold of an execution criterion sent by MN 110b to UE 120. If UE 120 determines that the quality is greater than the threshold, then the execution criterion is met. For CHO, instead of UE 120 sending a measurement report to MN 110b (which may be forwarded to SN 110a), the UE may determine that the execution criterion for the candidate PSCell (e.g., B1 event criterion or A3 / A5 event criterion) is met, and UE 120 may perform a handover to the candidate PSCell.

[0133] As shown, if SN 110a decides to change the candidate SN list, then in step 8, SN 110a may initiate another conditional SN change by sending a new candidate SN addition list to MN 110b in an Xn message. Since the UE 120 channel conditions are constantly changing, UE 120 may send a subsequent measurement report after a certain time. The new measurement report (e.g., the measurement report sent at time t2) may be different from the measurement report sent in step 1 (i.e., the measurement report sent at time t1). Therefore, the new measurement report may indicate to the SN that some candidate cells may no longer be suitable for the candidate SN list.

[0134] In some examples, such as Fig. 9 As shown, SN 110a may decide to release CSN2 and include only CSN1 in the SN add list. Therefore, at step 9, MN 110b may send a candidate add / release list to UE 120. In addition, MN 110b may perform an SN release procedure with CSN2 at steps 10 and 11.

[0135] Fig.10 A second call flow diagram 1000 is shown illustrating example communications between a UE, a MN, and a SN according to various aspects of the present disclosure. Fig. 9 As shown in the first option shown, the SN may perform both: identifying a set of one or more PSCells that may be configured as candidate cells, and determining execution criteria for the candidate cells.

[0136] Similar to Fig. 9 , a triggering event (e.g., HO failure or RLF) may cause UE 120 to send a measurement report identifying CSN1 and CSN2 to MN 110b configured for measurement at step 1, and MN 110b may forward the measurement report to SN 110a. SN 110a may select candidate cells (again, CSN1 and CSN2) for a candidate SN list based on the measurement report. Again, at step 2, SN 110a may send the candidate SN list to MN 110b in an Xn message so that MN 110b may perform the SN addition procedure (at steps 3 to 6).

[0137] and Fig. 9 Unlike the example shown in Fig.10 SN 110a in step 7 may also determine execution criteria for candidate cells and signal information about the execution criteria to MN 110b. MN 110b may include the execution criteria in the RRC reconfiguration message sent to UE 120 in step 7. There may be various options for sending the execution criteria from SN 110a to MN 110b.

[0138] In some examples, the RRC message may include an execution criterion configuration for each candidate cell in a transparent container. In some examples, the RRC message may include an RRC reconfiguration for each candidate cell in the set in a transparent container.

[0139] In some examples, according to the first option, MN 110b may be allowed to modify the execution criteria in the Xn message from SN 110a to MN 110b. Thus, the RRC message sent by MN 110b to UE 120 may signal information about the candidate cells and the modified execution criteria (similar to Fig. 9 options shown in ).

[0140] In some examples, according to the second option, such as Fig.10 As shown in step 2 of , SN 110a may include the conditional SN change execution criteria in a transparent container of SNs to MNs so that MN 110b may modify it. In this case, MN 110b may forward the container (without modification) to the UE only in the SN defined execution criteria and forward the candidate SN reconfiguration in the RRC reconfiguration message sent by MN 110b to UE 120.

[0141] In some examples where the UE is configured with conditional SN change configurations from both MN 110b and SN 110a, UE 120 may monitor both configurations independently and, accordingly, UE 120 may trigger an SN change (e.g., based on a first occurrence condition) when any one of the MN-defined or SN-defined execution criteria is met.

[0142] In some aspects, after performing an SN change to a new SN (e.g., CSN1 or CSN2), UE 120 may stop monitoring the execution conditions (e.g., criteria) configured by old SN 110a. In this case, UE 120 may notify MN 110b of the change of SN (e.g., via an RRC reconfiguration complete message). In response, MN 110b may clean up the candidate SN configuration selected by the old SN. For example, if the old candidate cells are no longer suitable as candidate SNs, MN 110b deletes them.

[0143] Fig.11 A communication device 1100 is shown, which may include devices configured to perform operations for the techniques disclosed herein (such as Figure 61100). The communication device 1100 includes a processing system 1102 coupled to a transceiver 1108. The transceiver 1108 is configured to transmit and receive signals for the communication device 1100, such as the various signals described herein, via an antenna 1110. The processing system 1102 may be configured to perform processing functions for the communication device 1100, including processing signals received by and / or to be transmitted by the communication device 1100.

[0144] The processing system 1102 includes a processor 1104 coupled to a computer-readable medium / memory 1112 via a bus 1106. In certain aspects, the computer-readable medium / memory 1112 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 1104, cause the processor 1104 to perform Figure 6 11 or other operations for performing the various techniques discussed herein. In some aspects, the computer-readable medium / memory 1112 stores code 1114 for identifying (e.g., for identifying a set of one or more candidate cells for conditional addition or change of the SN for the UE based on the execution criteria) and code 1116 for signaling (e.g., for signaling information about the set of candidate cells to the MN). In some aspects, the processor 1104 has circuits configured to implement the code stored in the computer-readable medium / memory 1112. The processor 1104 includes circuits 1124 for identifying (e.g., for identifying a set of one or more candidate cells for conditional addition or change of the SN for the UE based on the execution criteria) and circuits 1126 for signaling (e.g., for signaling information about the set of candidate cells to the MN).

[0145] Fig.12 A communication device 1200 is shown, which may include devices configured to perform operations for the techniques disclosed herein (such as Figure 7 1200). The communication device 1200 includes a processing system 1202 coupled to a transceiver 1208. The transceiver 1208 is configured to send and receive signals for the communication device 1200, such as the various signals described herein, via an antenna 1210. The processing system 1202 may be configured to perform processing functions for the communication device 1200, including processing signals received by and / or to be transmitted by the communication device 1200.

[0146] The processing system 1202 includes a processor 1204 coupled to a computer-readable medium / memory 1212 via a bus 1206. In certain aspects, the computer-readable medium / memory 1212 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 1204, cause the processor 1204 to perform Figure 7 1204 includes a circuit 1224 for receiving (e.g., for receiving a signal notification from the SN that identifies a set of candidate cells for conditional addition or change of the SN for the UE based on the execution criteria) and a circuit 1226 for signaling (e.g., for signaling configuration information about the set of candidate cells to the UE). In some aspects, the processor 1204 has circuits configured to implement the code stored in the computer-readable medium / memory 1212. The processor 1204 includes a circuit 1224 for receiving (e.g., for receiving a signal notification from the SN that identifies a set of candidate cells for conditional addition or change of the SN for the UE based on the execution criteria) and a circuit 1226 for signaling (e.g., for signaling configuration information about the set of candidate cells to the UE).

[0147] Fig.13 A communication device 1300 is shown, which may include devices configured to perform operations for the techniques disclosed herein (such as Figure 8 1300). The communication device 1300 includes a processing system 1302 coupled to a transceiver 1308. The transceiver 1308 is configured to transmit and receive signals for the communication device 1300, such as the various signals described herein, via an antenna 1310. The processing system 1302 may be configured to perform processing functions for the communication device 1300, including processing signals received by and / or to be transmitted by the communication device 1300.

[0148] The processing system 1302 includes a processor 1304 coupled to a computer readable medium / memory 1312 via a bus 1306. In some aspects, the computer readable medium / memory 1312 is configured to store instructions (e.g., computer executable code) that, when executed by the processor 1304, cause the processor 1304 to perform Figure 81314, code 1316 for detecting (e.g., for detecting that one of the candidate cells satisfies the execution criteria), and code 1318 for taking action (e.g., for taking action based on the detection to add or change the candidate cell to the SN). In some aspects, the processor 1304 has circuits configured to implement the code stored in the computer-readable medium / memory 1312. Processor 1304 includes circuitry 1324 for receiving (e.g., for receiving configuration information from the MN that identifies a set of candidate cells for conditional addition or change of the SN for the UE based on execution criteria), circuitry 1326 for detecting (e.g., for detecting that one of the candidate cells satisfies the execution criteria), and circuitry 1328 for taking action (e.g., for taking action based on the detection to add or change the candidate cell to the SN).

[0149] Example aspects

[0150] Aspect 1. A method for wireless communication performed by a user equipment (UE), comprising: receiving configuration information from a master node (MN), the configuration information identifying a set of candidate cells and execution criteria for conditional addition or change of a secondary node (SN) for the UE; detecting that one of the candidate cells satisfies the execution criteria; and taking action based on the detection to add or change the candidate cell to the SN.

[0151] Aspect 2. The method according to aspect 1, wherein the configuration information is received by the UE in a radio resource control (RRC) message.

[0152] Aspect 3. A method according to Aspect 2, wherein the RRC message includes at least one of the following information for conditional addition or change of SN: RRC configuration change of the source cell, conditional SN addition or change execution criterion configuration for each candidate cell in the set, or RRC reconfiguration for each candidate cell in the set.

[0153] Aspect 4. The method according to aspect 3, wherein the RRC message includes an execution criterion configuration for each candidate cell in a transparent container.

[0154] Aspect 5. The method according to any one of Aspects 1 to 4 further includes: sending a radio resource control (RRC) message to the MN, the RRC message indicating when a conditional SN addition or change execution criterion is satisfied when the selected cell satisfies the conditional SN addition or change execution criteria if the configuration of the selected candidate cell in the set is valid.

[0155] Aspect 6. A method according to any one of Aspects 1 to 5, wherein the configuration information indicates first configuration information determined by the MN and second configuration information determined by the SN, the UE independently monitors execution criteria according to the first configuration and the second configuration; and when any one of the execution criteria according to the first configuration or the second configuration is met, the SN change is performed on the candidate cell.

[0156] Aspect 7. The method according to aspect 6, wherein after performing an SN change on a candidate cell, the UE stops monitoring an execution criterion determined by the old SN.

[0157] Aspect 8. The method according to aspect 6 or 7 further comprises: sending a notification to the MN indicating that the SN change of the candidate cell has been performed.

[0158] Aspect 9. The method according to aspect 8, wherein the notification is sent via a radio resource control (RRC) reconfiguration complete message.

[0159] Aspect 10. A method for wireless communication performed by a secondary node (SN), comprising: identifying a set of one or more candidate cells for conditional addition or change of the SN for a user equipment (UE) based on an execution criterion; and signaling information about the set of candidate cells to a master node (MN).

[0160] Aspect 11. The method according to aspect 10, wherein information about the set of candidate cells is signaled to the MN via a message without execution criteria; and the MN determines the execution criteria for the candidate cells and signals the candidate cells and the execution criteria to the UE.

[0161] Aspect 12. The method according to aspect 10 or 11, further comprising: determining an execution criterion for the candidate cell; and signaling information about the execution criterion to the MN.

[0162] Aspect 13. The method according to aspect 12, wherein the MN is allowed to modify the execution criteria for the candidate cells and signal information about the candidate cells and the modified execution criteria to the UE.

[0163] Aspect 14. The method according to aspect 12 or 13, wherein the SN signals to the MN information about the execution criteria to be forwarded to the UE without modification.

[0164] Aspect 15. The method according to aspect 14, wherein the SN signals information about the execution criteria in a transparent container; and the MN forwards the transparent container to the UE.

[0165] Aspect 16. The method according to any one of aspects 10 to 15, further comprising: deciding to change the set of one or more candidate cells; and signaling information about the change to the MN.

[0166] Aspect 17. A method for wireless communication performed by a master node (MN), comprising: receiving a signal notification from a secondary node (SN), the signal notification identifying a set of candidate cells for conditional addition or change of the SN for a user equipment (UE) based on an execution criterion; and signaling configuration information about the set of candidate cells to the UE.

[0167] Aspect 18. The method according to aspect 17, wherein the MN receives information about a set of candidate cells from the SN via a message without execution criteria; and the MN determines the execution criteria for the candidate cells and signals the candidate cells and the execution criteria to the UE.

[0168] Aspect 19. The method according to aspect 17 or 18 further comprises: receiving information on execution criteria for candidate cells from the SN.

[0169] Aspect 20. The method according to aspect 19, further comprising: modifying an execution criterion for a candidate cell; and signaling information about the candidate cell and the modified execution criterion to the UE.

[0170] Aspect 21. The method according to aspect 20, wherein the SN signals to the MN the information about the execution criteria to be forwarded to the UE without modification; and the MN forwards the information about the execution criteria to the SN without modification.

[0171] Aspect 22. The method according to aspect 21, wherein the SN signals information about the execution criteria in a transparent container; and the MN forwards the transparent container to the UE.

[0172] Aspect 23. The method according to any one of aspects 17 to 22, further comprising: performing an SN adding procedure with a candidate cell.

[0173] Aspect 24. The method according to any one of aspects 17 to 23, wherein the configuration information is signaled to the UE in a radio resource control (RRC) message.

[0174] Aspect 25. The method according to any one of Aspects 17 to 24 further includes: receiving a radio resource control (RRC) message from the UE, the RRC message indicating when a conditional SN addition or change execution criterion is satisfied when the selected cell satisfies the selected cell if the configuration of the selected cell in the set is valid.

[0175] Aspect 26. A method according to any one of aspects 17 to 25, wherein the configuration information is signaled to the UE in a radio resource control (RRC) message, the RRC message including separate execution criteria for conditional SN addition and SN change.

[0176] Aspect 27. The method according to any one of Aspects 17 to 26 further includes: receiving a notification about a change of the SN from the UE via a radio resource control (RRC) reconfiguration completion message; and updating the candidate SN configuration to remove cells that are no longer suitable for conditional addition or change to a candidate cell for the SN.

[0177] Aspect 28. An apparatus for wireless communication performed by a user equipment (UE), comprising: a memory and at least one processor coupled to the memory, the at least one processor being configured to: receive configuration information from a master node (MN), the configuration information identifying a set of candidate cells for conditional addition or change of a secondary node (SN) for the UE based on execution criteria; detect that one of the candidate cells satisfies the execution criteria; and take action based on the detection to add or change the candidate cell to the SN.

[0178] Aspect 29. An apparatus for wireless communication performed by a secondary node (SN), comprising: a memory and at least one processor coupled to the memory, the at least one processor being configured to: identify a set of one or more candidate cells for conditional addition or change for a user equipment (UE) for the SN based on execution criteria; and signal information about the set of candidate cells to a master node (MN).

[0179] Aspect 30. An apparatus for wireless communication performed by a master node (MN), comprising: a memory and at least one processor coupled to the memory, the at least one processor being configured to: receive a signal notification from a secondary node (SN), the signal notification identifying a set of candidate cells for conditional addition or change for a user equipment (UE) for the SN based on execution criteria; and signal configuration information about the set of candidate cells to the UE.

[0180] Additional considerations

[0181] The method disclosed herein includes one or more steps or actions for implementing the described method. Without departing from the scope of the claims, the method steps and / or actions may be interchangeable with each other. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions may be modified without departing from the scope of the claims.

[0182] As used herein, a phrase referring to "at least one" of a list of items refers to any combination of those items, including single members. As an example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination with multiples of the same elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, cc, and cccc or any other ordering of a, b, and c).

[0183] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include computing, calculating, processing, deriving, investigating, searching (e.g., searching in a table, a database, or another data structure), ascertaining, etc. Likewise, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), etc. Likewise, "determining" may include resolving, selecting, choosing, establishing, etc.

[0184] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. It will be apparent to those skilled in the art that various modifications to these aspects will be apparent, and the general principles defined herein may be applicable to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but to conform to the full scope consistent with the language of the claims, wherein, unless specifically stated, the elements in the singular form are not intended to mean "one and only one", but "one or more". Unless otherwise clearly stated, the term "some" refers to one or more. All structural and functional equivalents of the elements of the various aspects described throughout this disclosure that are known or will be known to those of ordinary skill in the art are expressly incorporated herein by reference, and are intended to be encompassed by the claims. In addition, regardless of whether this disclosure is explicitly stated in the claims, anything disclosed herein is not intended to be dedicated to the public. Any claim element is not interpreted according to the provisions of the sixth paragraph of 35 U.S.C. § 112, unless the element is explicitly stated using the phrase "parts for...", or in the case of a method claim, the element is stated using the phrase "step for...".

[0185] The various operations of the method described above can be performed by any suitable component capable of performing the corresponding function. The component may include various hardware and / or software components and / or modules, including but not limited to circuits, application specific integrated circuits (ASICs) or processors. Typically, where operations are shown in the figures, these operations may have corresponding component-plus-function components with similar numbers.

[0186] The various illustrative logical blocks, modules, and circuits described in conjunction with the present disclosure may be implemented or executed using a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. A general purpose processor may be a microprocessor, but alternatively, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, a combination of one or more microprocessors with a DSP core, or any other such configuration.

[0187] If implemented in hardware, an example hardware configuration may include a processing system in a wireless node. The processing system may be implemented using a bus architecture. The bus may include any number of interconnecting buses and bridges, depending on the specific application and overall design constraints of the processing system. The bus may link together various circuits including a processor, a machine-readable medium, and a bus interface. In addition, the bus interface may be used to connect a network adapter to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the user terminal 120 (see Figure 1 ), a user interface (e.g., keyboard, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link various other circuits, such as timing sources, peripherals, voltage regulators, power management circuits, etc., which are known in the art and therefore will not be described. The processor may be implemented using one or more general and / or special purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuits that can execute software. Those skilled in the art will recognize how to best implement the described functionality for the processing system depending on the specific application and the overall design constraints imposed on the entire system.

[0188] If implemented in software, these functions can be stored or sent to a computer-readable medium as one or more instructions or codes. Software should be broadly understood to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or other. Computer-readable media include both computer storage media and communication media, and communication media include any media that facilitates the transfer of computer programs from one place to another. The processor may be responsible for managing the bus and general processing, including the execution of software modules stored on a machine-readable storage medium. A computer-readable storage medium may be coupled to a processor so that the processor can read information from the storage medium and write information to it. Alternatively, a storage medium may be integrated into a processor. For example, a machine-readable medium may include a transmission line, a carrier modulated by data, and / or a computer-readable storage medium having instructions stored thereon separated from a wireless node, all of which may be accessed by a processor through a bus interface. Alternatively or additionally, a machine-readable medium or any portion thereof may be integrated into a processor, such as a case where a cache and / or a general register file may be provided. For example, examples of machine-readable storage media may include RAM (random access memory), flash memory, ROM (read only memory), PROM (programmable read only memory), EPROM (erasable programmable read only memory), EEPROM (electrically erasable programmable read only memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage media, or any combination thereof. Machine-readable media may be embodied in a computer program product.

[0189] A software module may include a single instruction or many instructions, and may be distributed across several different code segments, between different programs, and across multiple storage media. A computer-readable medium may include several software modules. A software module includes instructions that, when executed by a device such as a processor, cause a processing system to perform various functions. A software module may include a transmission module and a reception module. Each software module may reside in a single storage device, or may be distributed across multiple storage devices. For example, when a triggering event occurs, a software module may be loaded from a hard drive into a RAM. During the execution of a software module, a processor may load some of the instructions into a cache to increase access speed. Then, one or more cache lines are loaded into a general register file to be executed by a processor. When referring to the functions of the following software modules, it will be understood that this function is implemented by a processor when executing instructions from the software module.

[0190] Likewise, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies (such as infrared (IR), radio and microwave), then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies (such as infrared, radio and microwave) are included in the definition of medium. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Disks, where disks typically reproduce data magnetically, while disks reproduce data optically with lasers. Thus, in some aspects, computer-readable media may include non-transitory computer-readable media (e.g., tangible media). Additionally, for other aspects, computer-readable media may include transitory computer-readable media (e.g., signals). Combinations of the above should also be included within the scope of computer-readable media.

[0191] Thus, certain aspects may include a computer program product for performing the operations presented herein. For example, this computer program product may include a computer-readable medium having instructions stored (and / or encoded) thereon, which may be executed by one or more processors to perform the operations described herein.

[0192] In addition, it should be understood that the module and / or other appropriate components for performing the methods and techniques described herein can be downloaded and / or otherwise obtained by a user terminal and / or a base station (if applicable). For example, this device can be coupled to a server to facilitate the transmission of components for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage component (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or a floppy disk, etc.) so that the user terminal and / or the base station can obtain various methods when being coupled to the device or providing a storage component thereto. In addition, any other suitable technology for providing the methods and techniques described herein to the device can be utilized. It should be understood that the claims are not limited to the precise configuration and components shown above. Various modifications, changes and variations can be made to the arrangement, operation and details of the above-mentioned methods and devices without departing from the scope of the claims.

Claims

1. A method for wireless communication by a user equipment (UE), comprising: receiving configuration information from a master node (MN), the configuration information identifying, for the UE, a set of candidate cells and an execution criterion for conditional addition or change of a secondary node (SN), wherein for an SN change initiated by the SN, the set of candidate cells is determined by the SN, and the execution criterion is determined by the MN or determined by the SN and signaled to the MN, and wherein the configuration information indicates first configuration information determined by the MN and second configuration information determined by the SN; independently monitoring execution criteria according to the first configuration information and the second configuration information; Detecting, according to the first configuration information or the second configuration information, that a candidate cell in the set of candidate cells satisfies the execution criterion; as well as An SN change is performed on the one candidate cell based on the detection.

2. The method according to claim 1, wherein: The configuration information is received by the UE in a Radio Resource Control (RRC) message.

3. The method according to claim 2, wherein: The RRC message includes at least one of the following information for the condition change of the SN: The source cell RRC configuration changes; A conditional SN change execution criterion configuration for each candidate cell in the set; or an RRC reconfiguration for each candidate cell in the set.

4. The method according to claim 1, further comprising: A radio resource control (RRC) message is sent to the MN, the RRC message indicating when the selected one of the candidate cells satisfies the conditional SN change execution criterion if the configuration of the selected one of the candidate cells in the set is valid.

5. The method according to claim 1, wherein: After performing the SN change on the one candidate cell, the UE stops monitoring the execution criterion determined by the old SN.

6. The method according to claim 1, further comprising: A notification is sent to the MN indicating that the SN change for the one candidate cell has been performed.

7. The method according to claim 6, wherein: The notification is sent via a Radio Resource Control (RRC) Reconfiguration Complete message.

8. A method for wireless communication by a master node (MN), comprising: receiving a signaling from a secondary node (SN) identifying, for a user equipment (UE), a set of candidate cells for conditional addition or change of the SN based on an execution criterion, wherein for a SN initiated SN change, the execution criterion is determined by the MN or determined by the SN and signaled to the MN; and Configuration information about the set of candidate cells and the execution criteria is signaled to the UE.

9. The method according to claim 8, further comprising: Execute the SN adding procedure with the candidate cell.

10. The method according to claim 8, wherein: The configuration information is signaled to the UE in a Radio Resource Control (RRC) message.

11. The method according to claim 8, further comprising: A radio resource control (RRC) message is received from the UE, the RRC message indicating when the selected one of the candidate cells in the set satisfies the execution criteria for the conditional addition or change of the SN if the configuration of the selected one of the candidate cells in the set is valid.

12. The method according to claim 8, wherein: The configuration information is signaled to the UE in a Radio Resource Control (RRC) message, the RRC message including the execution criteria for conditional SN addition and SN change.

13. The method according to claim 8, further comprising: receiving a notification of a change of the SN from the UE via a radio resource control (RRC) reconfiguration complete message; as well as The candidate SN configuration is updated to remove cells that are no longer suitable as candidate cells for conditional addition or change to a SN.

14. An apparatus for wireless communication by a user equipment (UE), comprising: Memory; as well as at least one processor coupled to the memory, the at least one processor configured to: receiving configuration information from a master node (MN), the configuration information identifying a set of candidate cells and execution criteria for conditional addition or change of a secondary node (SN) for the UE, wherein the set of candidate cells for a SN change initiated by the SN is determined by the SN, and the execution criteria is determined by the MN or determined by the SN and signaled to the MN, and wherein the configuration information indicates first configuration information determined by the MN and second configuration information determined by the SN; Detecting, according to the first configuration information or the second configuration information, that a candidate cell in the set of candidate cells satisfies the execution criterion; as well as An SN change is performed on the one candidate cell based on the detection.

15. An apparatus for wireless communication by a master node (MN), comprising: Memory; as well as at least one processor coupled to the memory, the at least one processor configured to: receiving a signaling from a secondary node (SN) that identifies, for a user equipment (UE), a set of candidate cells for conditional addition or change of the SN based on an execution criterion, wherein For SN initiated SN change, the execution criteria are determined by the MN or determined by the SN and signaled to the MN; and Configuration information about the set of candidate cells and the execution criteria is signaled to the UE.

16. An apparatus for wireless communication by a user equipment (UE), comprising: means for receiving configuration information from a master node (MN), the configuration information identifying a set of candidate cells and an execution criterion for conditional addition or change of a secondary node (SN) for the UE, wherein for an SN change initiated by the SN, the set of candidate cells is determined by the SN, and the execution criterion is determined by the MN or determined by the SN and signaled to the MN, and wherein the configuration information indicates first configuration information determined by the MN and second configuration information determined by the SN; A component configured to detect, according to the first configuration information or the second configuration information, that a candidate cell in the set of candidate cells satisfies the execution criterion; as well as means for performing an SN change on the one candidate cell based on the detecting.

17. An apparatus for wireless communication by a master node (MN), comprising: means for receiving a signaling from a secondary node (SN) identifying, for a user equipment (UE), a set of candidate cells for conditional addition or change of a SN based on an execution criterion, wherein for a SN initiated SN change, the execution criterion is determined by the MN or determined by the SN and signaled to the MN; and Means for signaling configuration information about the set of candidate cells and the execution criteria to the UE.

18. A non-transitory computer-readable storage medium having stored thereon instructions for wireless communication by a user equipment (UE), the instructions being executable by a processor to: receiving configuration information from a master node (MN), the configuration information identifying, for the UE, a set of candidate cells and an execution criterion for conditional addition or change of a secondary node (SN), wherein for an SN change initiated by the SN, the set of candidate cells is determined by the SN, and the execution criterion is determined by the MN or determined by the SN and signaled to the MN, and wherein the configuration information indicates first configuration information determined by the MN and second configuration information determined by the SN; independently monitoring execution criteria according to the first configuration information and the second configuration information; Detecting, according to the first configuration information or the second configuration information, that a candidate cell in the set of candidate cells satisfies the execution criterion; as well as An SN change is performed on the one candidate cell based on the detection.

19. A non-transitory computer-readable storage medium having stored thereon instructions for wireless communication by a master node (MN), the instructions being executable by a processor to: receiving a signaling from a secondary node (SN) identifying, for a user equipment (UE), a set of candidate cells for conditional addition or change of the SN based on an execution criterion, wherein for a SN initiated SN change, the execution criterion is determined by the MN or determined by the SN and signaled to the MN; and Configuration information about the set of candidate cells and the execution criteria is signaled to the UE.

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