Method for handover

Abstract

An apparatus comprising: means for receiving, from a target master node, an addition request along with an indication that the request relates to a conditional switch, the request comprising an identifier of a user equipment and an identifier of a source master node; means for checking using the identifier of the user equipment and the identifier of the source master node if the apparatus has a control target master cell prepared for the user equipment; means for comparing an existing secondary group configuration with the secondary group configuration included in the request; means for verifying, based on the comparison, that the same data radio bearer can be allocated for the add request; and means for responding to the request with an identifier of the tunnel endpoint for downlink data forwarding, the identifier of the tunnel endpoint having been assigned for a previous add request.

Description

Technical Field

[0001] The present invention relates to a switching method. Background Art

[0002] Conditional Handover (CHO) is a feature supported in LTE and 5G NR. CHO is similar in many ways to the previously known "normal" handover (HO), i.e., conventional HO. The main difference with respect to conventional HO is that in CHO, the user equipment (UE) starts preparing for handover to the target node only when additional CHO execution conditions are met. Another difference between conventional HO and CHO is the preparation of multiple target cells in CHO. Therefore, CHO reserves more resources at the target cell while waiting to be executed than conventional HO.

[0003] In the case of multiple preparations, each target primary node (MN) may prepare its own target secondary node (SN). Therefore, each target SN will also have to reserve the required resources.

[0004] When the secondary cell group (SCG) bearer configuration contains SN terminated bearers, the SN allocates the required tunnel endpoints. Information about the allocated tunnel endpoint identifier (TEID) is then forwarded to the source node, which can start data forwarding. In the case of CHO, this can be early data forwarding, which starts before the UE selects a target node for handover execution. Therefore, the source sends data to all prepared target nodes (after the target nodes have been prepared and configured to the UE). From the perspective of the target SN, if there are SN terminated bearers, it means that the same data may be received for all allocated TEIDs. This in turn requires the allocation and management of separate downlink (DL) buffers for the same data. In practice, this leads to severe resource over-allocation. Summary of the invention

[0005] Now, an improved method and a technical device for implementing the method have been invented, by which the above-mentioned problems are alleviated. Various aspects include methods, apparatus and non-transitory computer-readable media, which include a computer program or signal stored therein, which are characterized as described in the independent claims. Various details of the embodiments are disclosed in the dependent claims and the corresponding figures and description.

[0006] The independent claims set out the scope of protection sought by various embodiments of the invention. Embodiments and features described in this specification that do not fall within the scope of the independent claims, if any, are to be construed as examples that aid in understanding the various embodiments of the invention.

[0007] According to a first aspect, a device is provided comprising: a component for receiving an add request from a target master node together with an indication that the request involves a conditional switch, the request including an identifier of a user equipment and an identifier of a source master node; a component for verifying using the identifier of the user equipment and the identifier of the source master node if the device has a control target master cell prepared for the user equipment; a component for comparing an existing secondary group configuration with the secondary group configuration contained in the request; a component for verifying, based on the comparison, that the same data radio bearer can be allocated for the add request; and a component for responding to the request using an identifier of a tunnel endpoint for downlink data forwarding, which identifier has been allocated for a previous add request.

[0008] According to the second aspect, the device includes at least one processor and at least one memory, at least one memory having computer program code stored thereon, and the at least one memory and the computer program code are configured to use the at least one processor to cause the device to at least perform: receiving an add request from a target master node together with an indication that the request involves a conditional switch, the request including an identifier of a user equipment and an identifier of a source master node; if the device has a control target master cell prepared for the user equipment, using the identifier of the user equipment and the identifier of the source master node for verification; comparing the existing secondary group configuration with the secondary group configuration contained in the request; based on the comparison, verifying that the same data radio bearer can be allocated for the add request; and responding to the request using an identifier of a tunnel endpoint for downlink data forwarding, which identifier has been allocated for a previous add request.

[0009] According to an embodiment, the apparatus comprises computer program code configured to cause the apparatus to perform: identifying that the add request involves preparation from another master node; and assigning an identifier of the same tunnel endpoint for the add request.

[0010] According to an embodiment, the device includes a computer program code configured to cause the device to execute: if there is a matching add request, responding to the add request of the target master node by including an indication in the add request confirmation message that the target secondary node will share the identifier of the assigned tunnel endpoint for downlink data forwarding with any other target master node.

[0011] According to an embodiment, the apparatus comprises a computer program code configured to cause the apparatus to perform: checking whether the adding request comprises the same identification of the user equipment and the same secondary cell group configuration.

[0012] According to an embodiment, the apparatus comprises computer program code configured to cause the apparatus to perform: allocating only a single buffer for downlink data; and associating an identifier of a tunnel endpoint with the single buffer.

[0013] The method according to the third aspect includes: receiving an add request from a target master node together with an indication that the request involves a conditional switch, the request including an identifier of a user equipment and an identifier of a source master node; if the device has a control target master cell prepared for the user equipment, using the identifier of the user equipment and the identifier of the source master node for verification; comparing the existing secondary group configuration with the secondary group configuration included in the request; based on the comparison, verifying that the same data radio bearer can be allocated for the add request; and responding to the request using an identifier of a tunnel endpoint for downlink data forwarding, the identifier having been allocated for a previous add request.

[0014] According to the fourth aspect, an apparatus includes: a component for receiving, by a source node, a tunnel endpoint identifier of a first target master node and a first target tunnel endpoint identifier from a first target master node; a component for receiving, by the source node, a tunnel endpoint identifier of a second target master node and a second target tunnel endpoint identifier from a second target master node; a component for determining, by the source node, that the first target tunnel endpoint identifier and the second target tunnel endpoint identifier correspond to each other; and a component for deciding, by the source node, to send data addressed to a target secondary node via only one of the first target master node and the second target master node.

[0015] According to the fifth aspect, an apparatus includes at least one processor and at least one memory, computer program code being stored on the at least one memory, and the at least one memory and the computer program code being configured to use the at least one processor to cause the apparatus to at least execute: receiving a tunnel endpoint identifier of a first target master node and a first target tunnel endpoint identifier from a first target master node; receiving a tunnel endpoint identifier of a second target master node and a second target tunnel endpoint identifier from a second target master node; determining that the first target tunnel endpoint identifier and the second target tunnel endpoint identifier correspond to each other; and deciding to send data addressed to a target secondary node via only one of the first target master node and the second target master node.

[0016] According to a sixth aspect, a method includes: receiving, by a source node, a tunnel endpoint identifier of a first target master node and a first target tunnel endpoint identifier from a first target master node; receiving, by the source node, a tunnel endpoint identifier of a second target master node and a second target tunnel endpoint identifier from a second target master node; determining, by the source node, that the first target tunnel endpoint identifier and the second target tunnel endpoint identifier correspond to each other; and deciding, by the source node, to send data addressed to a target secondary node via only one of the first target master node and the second target master node.

[0017] According to the seventh aspect, an apparatus includes: a component for sending an add request related to conditional switching to a target secondary node, the add request including information of the requested secondary cell group bearer configuration and information of the identity of the user equipment; a component for receiving an add request confirmation from the target secondary node, the add request confirmation including the secondary cell group configuration and an indication that the identifier of the tunnel endpoint allocated by the target secondary node for downlink data is shared with another target primary node; a component for deciding to perform one of the following based on the indication: using indirect data forwarding and sending the identifier of the tunnel endpoint of the apparatus and the shared identifier of the tunnel endpoint allocated by the target secondary node for downlink data to the source primary node, or using direct data forwarding and sending the shared identifier of the tunnel endpoint allocated by the target secondary node for downlink data to the source primary node.

[0018] According to the eighth aspect, the device includes at least one processor and at least one memory, at least one memory having computer program code stored thereon, and the at least one memory and the computer program code are configured to use at least one processor to enable the device to at least execute: sending an add request related to conditional switching to a target secondary node, the add request including information about the requested secondary cell group bearer configuration and information about the user equipment identity; receiving an add request confirmation from the target secondary node, the add request confirmation including the secondary cell group configuration and an indication that the identifier of the tunnel endpoint allocated by the target secondary node for downlink data is shared with other target primary nodes; and deciding to execute one of the following based on the indication: using indirect data forwarding, and sending the identifier of the tunnel endpoint of the device and the shared identifier of the tunnel endpoint allocated by the target secondary node for downlink data to the source primary node, or, using direct data forwarding, and sending the shared identifier of the tunnel endpoint allocated by the target secondary node for downlink data to the source primary node.

[0019] According to a ninth aspect, a method includes: sending an add request related to conditional switching to a target secondary node, the add request including information about the requested secondary cell group bearer configuration and information about the identity of the user equipment; receiving an add request confirmation from the target secondary node, the add request confirmation including the secondary cell group configuration and an indication that the identifier of the tunnel endpoint allocated by the target secondary node for downlink data is shared with other target primary nodes; based on the indication, deciding to perform one of the following: using indirect data forwarding; and sending the identifier of the tunnel endpoint of the device and the shared identifier of the tunnel endpoint allocated by the target secondary node for downlink data to the source primary node, or using direct data forwarding and sending the shared identifier of the tunnel endpoint allocated by the target secondary node for downlink data to the source primary node.

[0020] According to the tenth aspect, an apparatus includes: a component for sending an add request related to conditional switching from a target primary node to a target secondary node, the add request including information of the requested secondary cell group bearer configuration and information of the identity of the user equipment; a component for receiving an add request confirmation from the target secondary node, the add request confirmation including the secondary cell group configuration and an indication that the identifier of the tunnel endpoint allocated by the target secondary node for downlink data is shared with another target primary node; a component for performing one of the following based on the indication: deciding to use indirect data forwarding and sending the identifier of the tunnel endpoint of the apparatus and the shared identifier of the tunnel endpoint allocated by the target secondary node for downlink data to the source primary node, or deciding to use direct data forwarding and sending the shared identifier of the tunnel endpoint allocated by the target secondary node for downlink data to the source primary node.

[0021] According to a further aspect, a computer-readable storage medium comprises code for use by an apparatus, which, when executed by a processor, causes the apparatus to perform the above-described method. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] For a more complete understanding of example embodiments, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0023] Figure 1 A schematic block diagram of a user equipment device for combining functions for implementing various embodiments is shown;

[0024] Figure 2 schematically illustrates a layout of a user equipment device according to an example embodiment;

[0025] Figure 3 A portion of an exemplary radio access network is shown;

[0026] Figure 4 shows a signaling diagram for a conditional handover procedure;

[0027] Figure 5a shows a signaling diagram according to an example embodiment;

[0028] Figure 5b shows a signaling diagram according to another example embodiment;

[0029] Figure 5c shows a signalling diagram according to yet another example embodiment;

[0030] Figure 6a A flow chart showing a method for signaling in conditional switching for a target SN according to an embodiment;

[0031] Figure 6b A flow chart showing a method for signaling in conditional handover for a target MN according to an embodiment;

[0032] Figure 7 A schematic block diagram of a network node device according to an embodiment is shown;

[0033] Figure 8a An exemplary signaling diagram for obtaining an identity of a user equipment according to a method is shown;

[0034] Figure 8b An exemplary signaling diagram for obtaining an identity of a user equipment according to another method is shown. DETAILED DESCRIPTION

[0035] Suitable means and possible mechanisms for performing operations for conditional switching are described in further detail below. Although the following focuses on 5G networks, the embodiments further described below are by no means limited to implementation only in said networks, and are applicable to any network that supports conditional switching.

[0036] In this regard, first refer to Figure 1 and Figure 2 ,in Figure 1 A schematic block diagram of an exemplary apparatus or electronic device 50 is shown which may incorporate arrangements according to embodiments. Figure 2 The layout of the device according to the exemplary embodiment is shown. Figure 1 and 2 components.

[0037] The electronic device 50 may be, for example, a mobile terminal or user equipment of a wireless communication system. The device 50 may include a housing 30 for incorporating and protecting the device. The device 50 may also include a display 32 and a keypad 34. Instead of a keypad, the user interface may be implemented as a virtual keyboard or a data entry system as part of a touch-sensitive display.

[0038] The device may include a microphone 36 or any suitable audio input that may be a digital or analog signal input. The device 50 may further include an audio output device, such as headphones 38, a speaker, or any one of an analog audio or digital audio output connection. The device 50 may also include a battery 40 (or the device may be powered by any suitable mobile energy device, such as a solar cell, a fuel cell, or a clock generator). The device may also include a camera 42 capable of recording or capturing images and / or videos. The device 50 may also include an infrared port 41 for short-range line-of-sight communication with other devices. In other embodiments, the device 50 may also include any suitable short-range communication solution, such as, for example, a Bluetooth wireless connection or a USB / Firewire wired connection.

[0039] The device 50 may include a controller 56 or processor for controlling the device 50. The controller 56 may be connected to a memory 58, which may store user data and instructions for implementation on the controller 56. The memory may be a random access memory (RAM) and / or a read-only memory (ROM). The memory may store computer-readable, computer-executable software including instructions that, when executed, cause the controller / processor to perform the various functions described herein. In some cases, the software may not be directly executed by the processor, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein. The controller 56 may be further connected to a codec (CODEC) circuit system 54, which is suitable for performing the coding and decoding of audio and / or video data or assisting in the coding and decoding performed by the controller.

[0040] The device 50 may include a radio interface circuit system 52, which is connected to the controller and is suitable for generating wireless communication signals, such as for communication with a cellular communication network, a wireless communication system or a wireless local area network. The device 50 may also include an antenna 44 connected to the radio interface circuit system 52 for transmitting radio frequency signals generated at the radio interface circuit system 52 to other (multiple) devices and for receiving radio frequency signals from other (multiple) devices.

[0041] In the following, different exemplary embodiments will be used as examples of access architectures to which the embodiments may be applied, based on a radio access architecture of Long Term Evolution Advanced (LTE-Advanced, LTE-A) or New Radio (NR, 5G), without limiting the embodiments to such architectures. It will be appreciated by those skilled in the art that the embodiments may also be applied to other kinds of communication networks with suitable devices by appropriately adjusting the parameters and processes. Some examples of other options for suitable systems are Universal Mobile Telecommunications System (UMTS) Radio Access Network (UTRAN or E-UTRAN), Long Term Evolution (LTE, same as E-UTRA), Wireless Local Area Network (WLAN or WiFi), Worldwide Interoperability for Microwave Access (WiMAX), Personal Communications Service (PCS), Wideband Code Division Multiple Access (WCDMA), systems using Ultra-Wideband (UWB) technology, sensor networks, mobile ad hoc networks (MANETs) and Internet Protocol Multimedia Subsystem (IMS) or any combination thereof.

[0042] Figure 3 An example of a simplified system architecture is depicted, showing only some elements and functional entities, all of which are logical units, whose implementation may differ from what is shown. Figure 3 The connections shown in are logical connections; the actual physical connections may be different. It is obvious to those skilled in the art that the system typically also includes Figure 3 Other functions and structures are shown. However, the embodiments are not limited to the systems given as examples, but a person skilled in the art may apply the solution to other communication systems having the necessary properties.

[0043] Figure 3 The example of FIG. 1 shows a portion of an exemplary radio access network.

[0044] Figure 3 Shown is a user equipment 300 and 302 configured to be wirelessly connected to an access node (such as (e / g) NodeB) 304 providing the cell on one or more communication channels in the cell. The physical link from the user equipment to the (e / g) NodeB is called an uplink or reverse link, and the physical link from the (e / g) NodeB to the user equipment is called a downlink or forward link. It should be understood that the (e / g) NodeB or its functions can be implemented by using any node (such as an integrated access and backhaul (IAB) node), host, server or access point, etc., suitable for this purpose.

[0045] The communication system generally includes more than one (e / g)NodeB, in which case the (e / g)NodeB can also be configured to communicate with each other via wired or wireless links designed for this purpose. These links can be used for signal transmission purposes. (e / g)NodeB is a computing device configured to control the radio resources of the communication system to which it is coupled. (e / g)NodeB can also be referred to as a base station, an access point or any other type of interface device, including a relay station capable of operating in a wireless environment. (e / g)NodeB includes or is coupled to a transceiver. A connection is provided from the transceiver of the (e / g)NodeB to an antenna unit, thereby establishing a bidirectional radio link to a user equipment. The antenna unit may include multiple antennas or antenna elements. (e / g)NodeB is also connected to a core network 310 (CN or next generation core network NGC). Depending on the system, the corresponding part on the CN side may be a service gateway (S-GW, routing and forwarding user data packets), a packet data network gateway (P-GW), for providing a connection of a user equipment (UE) to an external packet data network or a mobile management entity (MME), etc. The CN may include network entities or nodes which may be referred to as management entities. Examples of network entities include at least an Access and Mobility Management Function (AMF).

[0046] In 5G NR, the user plane function (UPF) can be used to separate the control plane and user plane functions. Among them, the packet gateway (PGW) controls and the user plane functions can be decoupled, whereby the data forwarding component (PGW-U) can be decentralized, while the PGW-related signaling (PGW-C) remains in the core. This allows packet processing and service aggregation to be performed closer to the edge of the network, thereby increasing bandwidth efficiency while reducing network load.

[0047] User equipment (also referred to as user equipment (UE), user terminal, terminal device, wireless device, mobile station (MS), etc.) shows a type of device where resources on the air interface are allocated and assigned, so any features described herein with user equipment can be implemented with corresponding network devices, such as relay nodes, eNBs and gNBs. An example of such a relay node is a layer 3 relay (self-backhaul relay) towards a base station.

[0048] A user device generally refers to a portable computing device including a wireless mobile communication device operating with or without a subscriber identity module (SIM), including but not limited to the following types of devices: mobile stations (mobile phones), smart phones, personal digital assistants (PDAs), cell phones, devices using wireless modems (alarms or measuring devices, etc.), laptop computers and / or touch screen computers, tablet computers, game consoles, notebooks, and multimedia devices. It should be understood that a user device may also be almost the only uplink device, an example of which is a camera or video camera that loads images or video clips to a network. A user device may also be a device with the ability to operate in an Internet of Things (IoT) network, which is a scenario in which an object is provided with the ability to transmit data over a network without human-to-human or human-to-computer interaction. Therefore, a user device may be an IoT device. A user device may also utilize a cloud. In some applications, a user device may include a small portable device with a radio component (such as a watch, headphones, or glasses), and performs calculations in the cloud. A user device (or in some embodiments, a layer 3 relay node) is configured to perform one or more of the user device functions. A user device may also be called a subscriber unit, a mobile station, a remote terminal, an access terminal, a user terminal, or user equipment (UE), just to name a few names or devices.

[0049] The various techniques described herein may also be applied to cyber-physical systems (CPS) (systems where cooperating computing elements control physical entities). CPS may enable the implementation and utilization of a large number of interconnected ICT devices (sensors, actuators, processor microcontrollers, etc.) embedded in physical objects at different locations. Mobile cyber-physical systems, where the physical systems in question have inherent mobility, are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robots and electronic devices transported by humans or animals.

[0050] Additionally, although the apparatus has been depicted as a single entity, it may be implemented as different units, processors and / or memory units ( Figure 1 not shown).

[0051] 5G enables the use of multiple-input multiple-output (MIMO) antennas, more base stations or nodes compared to LTE (the so-called small cell concept), including macro sites operating in coordinated operation with smaller stations and depending on service requirements, use cases and / or spectrum availability. The access nodes of the radio network form a transmit / receive (TX / Rx) point (TRP) and it is expected that UEs access a network of at least partially overlapping multiple TRPs (such as macro cells, small cells, pico cells, femto cells, remote radio heads, relay nodes, etc.). The access nodes may be equipped with massive MIMO antennas, i.e. very large antenna arrays consisting of, for example, hundreds of antenna elements, implemented in a single antenna panel or in multiple antenna panels, capable of using multiple simultaneous radio beams for communication with the UE. A UE may be provided with a MIMO antenna with an antenna array consisting of, for example, dozens of antenna elements implemented in a single antenna panel or in multiple antenna panels. Therefore, the UE can use one beam to access one TRP, use multiple beams to access one TRP, use one (common) beam to access multiple TRPs, or use multiple beams to access multiple TRPs.

[0052] 4G / LTE networks support some multi-TRP schemes, but in 5G NR, the multi-TRP feature is enhanced, for example, via the transmission of multiple control signals for the multi-TRP, which enables improved link diversity gain. In addition, high carrier frequencies (e.g., mmWave) together with massive MIMO antennas require new beam management processes for multi-TRP technology.

[0053] 5G mobile communications support a wide range of use cases and related applications including video streaming. Augmented reality is a different way of data sharing and various forms of machine-type applications (such as (massive) machine-type communications (mMTC), including vehicle safety, different sensors and real-time control. 5G is expected to have multiple radio interfaces. That is, below 6GHz, cmWave and mmWave, and can also be integrated with existing traditional radio access technologies (such as LTE). The integration with LTE can be implemented as a system at least in the early stages, where macro coverage is provided by LTE, and 5G radio interface access comes from small cells by aggregation to LTE. In other words, 5G is planned to support inter-RAT operability (such as LTE-5G) and inter-RI operability (inter-radio interface operability, such as below 6GHz-cmWave, below 6GHz-cmWave-mmWave). One of the concepts considered to be used in 5G networks is network slicing, in which multiple independent and dedicated virtual subnetworks (network instances) can be created within the same infrastructure to run services with different requirements for latency, reliability, throughput and mobility.

[0054] The frequency bands for 5G NR are divided into two frequency ranges: Frequency Range 1 (FR1), which includes the sub-6 GHz bands, i.e. the bands traditionally used by previous standards, but also includes new bands extended to cover potential new spectrum from 410 MHz to 7125 MHz, and Frequency Range 2 (FR2), which includes the bands from 24.25 GHz to 52.6 GHz. FR2 therefore includes bands in the mmWave range, which, due to their shorter range and higher available bandwidth, require a slightly different approach in radio resource management compared to bands in FR1.

[0055] The current architecture in LTE networks is completely distributed in the radio and completely concentrated in the core network. Low-latency applications and services in 5G require content to be close to the radio, which leads to local interruptions and multi-access edge computing (MEC). 5G enables analysis and knowledge generation to occur at the source of data. This method requires the use of resources that may be discontinuously connected to networks such as laptops, smart phones, tablet computers and sensors. MEC provides a distributed computing environment for application and service hosting. It also has the ability to store and process content in close proximity to cellular subscribers to obtain faster response times. Edge computing covers a wide range of technologies, such as wireless sensor networks, mobile data collection, mobile signature analysis, collaborative distributed peer-to-peer self-organizing networking and processing, which can also be classified as local cloud / fog computing and grid / grid computing, dew computing, mobile edge computing, micro-cloud, distributed data storage and retrieval, autonomous self-healing networks, remote cloud services, augmented and virtual reality, data caching, Internet of Things (large-scale connection and / or latency critical), critical communications (autonomous vehicles, traffic safety, real-time analysis, time-critical control, healthcare applications).

[0056] The communication system may also be able to communicate with or utilize services provided by other networks, such as the public switched telephone network or the Internet 312. The communication network may also be able to support the use of cloud services, for example, at least a portion of the core network operations may be performed as a cloud service (this is in the Figure 3 314). The communication system may also include a central control entity or the like, providing facilities for networks of different operators to collaborate, for example in spectrum sharing.

[0057] Edge cloud can be brought into the radio access network (RAN) by leveraging network function virtualization (NFV) and software defined networking (SDN). Using edge cloud can mean performing access node operations at least partially in a server, host or node operatively coupled to a remote radio head or base station including the radio part. The node operations may also be distributed among multiple servers, nodes or hosts. The application of cloud RAN architecture enables RAN real-time functions to be performed on the RAN side (in distributed units, DU), while non-real-time functions are performed in a centralized manner (in centralized units CU 308).

[0058] It should also be understood that the division of labor between core network operations and base station operations may be different from LTE or even non-existent. Some other technological advances that may be used are big data and all-IP, which can change the way networks are built and managed. 5G (or New Radio) NR networks are designed to support multiple layers, where MEC servers can be placed between the core and the base station or Node B (gNB). It should be understood that MEC can also be applied in 4G networks. gNB is the next generation Node B (or new Node B) that supports 5G networks (i.e., NR).

[0059] 5G can also utilize non-ground nodes, such as access nodes 306, to enhance or supplement the coverage of 5G services, for example by providing backhaul, wireless access to wireless devices, service continuity for machine-to-machine (M2M) communications, service continuity for Internet of Things (IoT) devices, service continuity for passengers on board of transportation vehicles, ensuring service availability for critical communications, and / or ensuring service availability for future rail / sea / air communications. . The non-ground node may have a fixed position relative to the surface of the earth, or the non-ground node may be a mobile non-ground node that can move relative to the surface of the earth. The non-ground node may include satellites and / or HAPS. Satellite communications may utilize geostationary earth orbit (GEO) satellite systems, but may also utilize low earth orbit (LEO) satellite systems, especially large constellations (systems deploying hundreds of (nano) satellites). Each satellite in a large constellation may cover several satellite-supporting network entities that create a cell on the ground. A cell on the ground may be created by a relay node 304 on the ground or by a gNB located on the ground or in a satellite.

[0060] Those skilled in the art understand that the depicted system is only an example of a part of a radio access system. In practice, the system may include multiple (e / g)NodeBs, user equipment may access multiple radio cells, and the system may also include other devices, such as physical layer relay nodes or other network elements. At least one (e / g)NodeB may be a home (e / g)NodeB. In addition, in a geographical area of ​​a radio communication system, multiple different types of radio cells and multiple radio cells may be provided. A radio cell may be a macro cell (or umbrella cell), which is a large cell, typically having a diameter of up to tens of kilometers, or a smaller cell, such as a micro cell, a femto cell or a pico cell. Figure 1 The (e / g)NodeB in an access node can provide any of these cells. A cellular radio system can be implemented as a multi-layer network comprising several types of cells. Typically, in a multi-layer network, one access node provides one or more cells of one type, so multiple (e / g)NodeBs are required to provide this network structure.

[0061] In order to meet the needs of improving the deployment and performance of communication systems, the concept of "plug and play" (e / g) NodeB is introduced. Generally, in addition to the home (e / g) NodeB (H(e / g) NodeB), the network that can use "plug and play" (e / g) NodeB includes the home node B gateway or HNB-GW ( Figure 1 The HNB gateway (HNB-GW) usually installed in the operator's network can aggregate services from a large number of HNBs back to the core network.

[0062] The Radio Resource Control (RRC) protocol is used in various wireless communication systems to define the air interface between the UE and the base station (such as eNB / gNB). The protocol is specified by 3GPP in TS36.331 for LTE and TS38.331 for 5G. In RRC, the UE can operate in idle mode or in connected mode in LTE and in 5G, where the radio resources available to the UE depend on the mode in which the UE is currently located. In 5G, the UE can also operate in inactive mode. In RRC idle mode, the UE is not connected for communication, but the UE is able to listen to paging messages. In RRC connected mode, the UE can operate in different states, such as CELL_DCH (dedicated channel), CELL_FACH (forward access channel), CELL_PCH (cell paging channel) and URA_PCH (URA paging channel). The UE can communicate with the eNB / gNB via various logical channels (e.g., Broadcast Control Channel (BCCH), Paging Control Channel (PCCH), Common Control Channel (CCCH), Dedicated Control Channel (DCCH), Dedicated Traffic Channel (DTCH)).

[0063] The transitions between states are controlled by the state machine of RRC. When the UE is powered on, it is in disconnected mode / idle mode. The UE can transition to RRC connected mode with an initial attach or connection establishment. If there is no activity from the UE for a short period of time, the eNB / gNB can suspend its session by moving to RRC inactive mode and can resume its session by moving to RRC connected mode. The UE can move to RRC idle mode from RRC connected mode or from RRC inactive mode.

[0064] The actual user and control data from the network to the UE is transmitted via downlink physical channels, which in 5G include the Physical Downlink Control Channel (PDCCH) carrying the necessary downlink control information (DCI), the Physical Downlink Shared Channel (PDSCH) carrying user data and user system information, and the Physical Broadcast Channel (PBCH) carrying the necessary system information to enable the UE to access the 5G network.

[0065] User and control data from the UE to the network are transmitted via uplink physical channels, which in 5G include a physical uplink control channel (PUCCH) for uplink control information including HARQ (Hybrid Automatic Repeat Request) feedback confirmation for link adaptation, scheduling requests and downlink channel state information, a physical uplink shared channel (PUSCH) for uplink data transmission, and a physical random access channel (PRACH) used by the UE to request connection establishment called random access.

[0066] Conditional Handover (CHO) is a feature supported in LTE and 5G NR. CHO is similar in many ways to the previously known "normal" handover (HO), i.e., traditional HO. An exemplary signaling diagram for CHO is shown in Figure 4 As shown in . The configured event triggers the UE to send a measurement report to its current serving node e / gNB. During the HO process, the current serving node may be referred to as the source node. Based on the report, the source node typically prepares one or more candidate target nodes for the handover. The preparation includes a handover request sent to each target node and a handover request confirmation received from each target node. The source node then sends a handover command (including an RRC reconfiguration message) to the UE. For a traditional HO, the UE will immediately switch to the target node by reconfiguring it as its new serving e / gNB node to complete the handover.

[0067] In contrast, with CHO, the UE will only access the target node once an additional CHO execution condition is met. This condition is configured by the source cell during the HO command, for example. Thus, the UE monitors whether the CHO execution condition is met, while user data can be transmitted between the UE and the source node. Only when the CHO execution condition is met does the UE start preparing to handover to the target node.

[0068] Dual Connectivity (DC) is a feature supported in LTE and 5G NR that enables aggregation of two radio links at the PDCP (Packet Data Convergence Protocol) layer level. For resource aggregation, a UE in RRC_CONNECTED state is allocated two radio links from two different network nodes that can be connected via a non-ideal backhaul. The first node, the primary node (MN), acts as a mobility and signaling anchor, and the second node, the secondary node (SN), provides additional local radio resources for the UE. The two resource sets are called the primary cell group (MCG, associated with the MN) and the secondary cell group (SCG, associated with the SN). The MN can be an LTE eNB or an NR gNB. The SN can be an LTE eNB or an NR gNB. The MN and the SN can be the same node.

[0069] Because users can be connected to MCG and SCG simultaneously, dual connectivity can improve user throughput and mobility robustness, and improve load balancing between MCG and SCG resources.

[0070] CHO has been specified for UEs configured with dual connectivity. In this document, the source MN node (controlling the primary cell PCell) sends a handover request to the target MN node (controlling the target PCell), which in turn selects a secondary node (controlling the target PSCell) and prepares it as part of the CHO preparation. When the CHO execution conditions are met, the UE performs access to the target PCell and PSCell.

[0071] One of the main differences between traditional HO and CHO is the preparation of multiple target cells. In the future, CHO is expected to be more widely used to ensure that the UE has a prepared target when the execution conditions are met. This means that CHO reserves more resources at the target cell than traditional HO while waiting for execution. 3GPP has a mechanism that allows the target node to optimize the allocation. Because it may be aware of each preparation involving the same UE.

[0072] In the case of multiple preparations, each target primary node (MN) may prepare its own target secondary node (SN). Therefore, each target SN will also have to reserve the required resources.

[0073] Since each target MN receives the same measurements, it may happen that they decide to prepare the same SN (especially if the cloud deployment enables SN-wide coverage area). If this SN is the same as the one used in the source MN, the SN receives the UE ID assigned for communication with the source MN and it can therefore identify the preparation related to an already known UE. In addition, by comparing the SCG configurations, the target SN is able to identify that the target MN has provided the same configuration for the bearers terminated by the SN.

[0074] In the following, several embodiments will be described with a view to avoiding forcing the SN to manage the same data coming via different paths.

[0075] Figure 5aA signaling diagram according to an example embodiment is shown. In this example, there are two target MNs, namely target MN 1 and target MN 2, but in actual implementations, the number of target MNs that can participate in CHO may be different from two, for example, more than two. The UE detects a configured event, which triggers the UE to send a measurement report 501 to its current serving node e / gNB. During the HO process, the current serving node may be referred to as a source node. Based on the report, the source MN node prepares one or more candidate target nodes for handover. The source MN node (controlling the primary cell PCell) sends a handover request 502 to a candidate target MN node (controlling the target PCell), which in turn selects a target secondary node (controlling the target PSCell) and sends an add request message 503 to it. In this example, the candidate target MN node is target MN 1 at this stage, but it may also be target MN 2 or another target MN. The add request message may include information of the requested secondary cell group bearer configuration (SCG Config), which includes information of the capabilities of the UE. The target SN checks the add request message and decides 504 to prepare PSCell 1 and provides secondary cell group bearer configuration SCG Config 1. The target SN also provides 505 tunnel endpoint identification information (TEID) for downlink data forwarding. Then, the target SN sends 506 an add request confirmation together with SCG Config 1 to the target MN node.

[0076] The target MN 1 node generates 507 a first conditional handover configuration (CHO 1 config), and includes the secondary cell group configuration 1 (SCG config 1) received from the target SN in the first conditional handover configuration.

[0077] The target MN 1 node sends 508 a handover request confirmation message to the source MN, and the source MN prepares 509 an RRC reconfiguration message and sends 509 the RRC reconfiguration message to the UE. The RRC reconfiguration message includes a first conditional handover configuration.

[0078] The configured event may later trigger the UE to send 510 another measurement report to its current serving node e / gNB for possible handover. The current serving node then sends 510 another measurement report to another target MN (such as Figure 5a The target MN 2 sends a handover request 511. The target MN 2 node sends an add request message 512 to the target SN. The add request message may include the requested secondary cell group bearer configuration information and the UE identification information.

[0079] When the target SN has received the add request message, the target SN checks from which target MN the message was received. Based on the check, when the target SN detects that the add request message 512 has been sent by a different target MN than the previous add request message 503 (in Figure 5a When the target MN 2 in the example of FIG. 5 is added, the target SN can also compare the previous SCG configuration (e.g., SGC configuration 1 prepared in step 504) with the SCG configuration of the add request message 512. By comparing the SCG configurations, the target SN is able to recognize that other target MNs have already provided the same configuration for the SN terminated bearer, but it involves the same UE and the same SCG bearer configuration for the SN terminated bearer. Therefore, the target SN decides 513 to prepare PSCell 1 and provide the same secondary cell group bearer configuration SCG configuration 1.

[0080] In other words, once the target SN receives an add request message from the target MN 2 together with an indication that the add request message involves CHO, the target SN can use the included UE's (UE ID) and source MN's (MN ID) identifiers to check whether the target SN has a PSCell prepared for the UE. If the target SN finds a PSCell prepared for the UE, the target SN can compare the existing SCG configuration with the SCG configuration associated with the request to verify 514 whether the same data radio bearer (DRB) can be allocated in the new request. Once this is confirmed, the target SN can respond to the new add request with the TEID for DL ​​data forwarding that has been allocated for other requests. The target SN then sends an add request confirmation 515 with SCG configuration 1 to the target MN 2 node.

[0081] The target MN 2 node transmitting the add request message 512 generates 516 a second conditional handover configuration (CHO configuration 2) and includes the secondary cell group configuration 1 (SCG configuration 1) received from the target SN in the first conditional handover configuration.

[0082] The target MN 2 node sends 517 a handover request confirmation message to the source MN, and the source MN prepares and sends 518 an RRC reconfiguration message to the UE. The RRC reconfiguration message includes a second conditional handover configuration (CHO config2).

[0083] According to an embodiment, when the target SN identifies that the add request is related to a provision from another target MN (ie, related to the same UE and the same SCG configuration is provided for SN terminated bearers), the same TEID is allocated to the request.

[0084] According to an embodiment, when responding to an add request to a target MN, the target SN may include an indication (e.g., a flag) to the add request confirmation message 515, i.e., if there is a matching add request, the target SN will share the allocated TEID for DL ​​data forwarding with any other target MN. For example, a matching add request may be determined by checking whether the add request includes the same UE identity and the same SCG configuration as another add request.

[0085] The target MN may then forward the TEID from the target SN to the source MN, either directly as the TEID for data forwarding (in the case of direct data forwarding) or as additional information associated with the MN's own TEID.

[0086] Figure 5b A signaling diagram according to another example embodiment is shown. Figure 5a In an embodiment, the UE detects a configured event, which triggers the UE to send a measurement report 501 to its current serving node e / gNB. During the HO process, the current serving node may be referred to as a source node. Based on the report, the source MN node prepares one or more candidate target nodes for handover. The source MN node (controlling the primary cell PCell) sends a handover request 502 to a candidate target MN node (controlling the target PCell), which in turn selects a target secondary node (controlling the target PSCell) and sends an add request message 503 to it. The add request message may include information of the requested secondary cell group bearer configuration (SCG Config), which includes information of the capabilities of the UE. The target SN examines the add request message and decides 504 to prepare PSCell 1 and provide a first secondary cell group bearer configuration SCG configuration 1. The target SN also provides 505 identification information of a tunnel endpoint (TEID) for downlink data forwarding. The target SN then sends 506 an add request confirmation with SCG configuration 1 to the target MN node.

[0087] The target MN node generates 507 a first conditional handover configuration (CHO 1Config), and includes in the first conditional handover configuration the first secondary cell group configuration 1 (SCG Config1) received from the target SN.

[0088] The target MN node sends 508 a handover request confirmation message to the source MN, and the source MN prepares and sends 509 an RRC reconfiguration message to the UE. The RRC reconfiguration message includes a first conditional handover configuration.

[0089] The configured event may later trigger the UE to send 510 another measurement report to its current serving node e / gNB for possible handover. The current serving node then sends 510 another measurement report to another target MN (such as Figure 5bThe target MN 2) sends a handover request 511. The target MN node sends an add request message 512 to the target SN. The add request message may include the requested secondary cell group bearer configuration information and the UE identification information.

[0090] When the target SN has received the add request message, the target SN checks from which target MN the message was received. Based on the check, when the target SN detects that the add request message 512 has been sent by a different target MN than the previous add request message 503, the target SN may also compare the previous SCG configuration (e.g., SGC configuration 1 prepared in step 504) with the SCG configuration of the add request message 512. By comparing the SCG configurations, the target SN is able to recognize that the target MN has provided the same configuration for the SN terminated bearer, but it involves the same UE and the same SCG bearer configuration for the SN terminated bearer. Therefore, the target SN decides 513 to prepare PSCell 1 and provide the same secondary cell group bearer configuration SCG configuration 1.

[0091] If the target SN finds a PSCell prepared for the UE and the existing SCG configuration corresponds to the SCG configuration associated with the request, the target SN verifies 514 that the same data radio bearer (DRB) can be allocated in the new request. Once this is confirmed, the target SN can respond to the new add request with the TEID for DL ​​data forwarding allocated for other requests. The target SN then sends an add request confirmation 515 with SCG configuration 1 to the target MN node and an indication that the TEID for DL ​​data forwarding is shared with another target MN, or if the indication is provided in advance, the indication is that the TEID for DL ​​data forwarding can be shared with another target MN. Shared data forwarding means that the target MN forwards the TEID of the SN to the source node, so that direct forwarding between the source node (source MN / or source SN) and the target SN is enabled without the target MN intercepting packets.

[0092] If the target MN node transmitting the add request message 512 decides to enable direct data forwarding instead of indirect forwarding, the target MN node sends 519 the TEID of the target SN to the source node, which may be the source MN or the source SN.

[0093] The target MN node also generates 520 a second conditional handover configuration (CHO configuration 2) and includes the secondary cell group configuration 1 (SCG configuration 1) received from the target SN in the first conditional handover configuration.

[0094] The target MN node sends 521 a handover request confirmation message included in the SCG configuration to the source MN.

[0095] The source MN prepares 522 an RRC reconfiguration message and sends 522 the RRC reconfiguration message to the UE. In addition, the RRC reconfiguration message includes a second conditional handover configuration (CHO configuration 2).

[0096] Figure 5c FIG. 5 shows a signaling diagram according to another exemplary embodiment. The process from 501 to 514 is similar to Figure 5b Embodiment. However, in this example embodiment of the present disclosure, if there is a matching add request, the target SN decides to share the allocated TEID with any other target MN for downlink data forwarding. Therefore, the target SN includes an indication such as a flag (e.g., 1 bit) to indicate the target MN and the source SN about sharing the allocated TEID. Therefore, the target SN sends an add request confirmation 515 with SCG configuration 1 to the target MN node and an indication that the TEID for DL ​​data forwarding is shared with another target MN.

[0097] The target MN receives the add request confirmation and indication with SCG configuration 1 and based on the indication, the target MN decides to use indirect data forwarding instead of direct data forwarding in processing stage 519. Therefore, the target MN sends the TEID of the target MN to the source node and also includes the TEID of the target SN.

[0098] The target MN node also generates 520 a second conditional handover configuration (CHO configuration 2), and includes in the second conditional handover the first secondary cell group configuration 1 (SCG configuration 1) in the first conditional handover configuration received from the target SN.

[0099] The target MN node sends 521 a handover request confirmation message contained in CHO configuration 2 and the TEID of the target MN and the TEID of the target SN to the source MN.

[0100] The source MN prepares 522 an RRC reconfiguration message and sends 522 the RRC reconfiguration message to the UE. In addition, the RRC reconfiguration message includes a second conditional handover configuration (CHO configuration 2).

[0101] In step 523, the source MN can now start forwarding data to the target MN / SN because a data path is established between the source MN and the target MN / SN. If the source MN decides to start data forwarding after the data path is established, it is called early data forwarding. Since the user data is already available at the target MN / SN, early data forwarding enables the network to reduce gaps in user data transmission when the UE actually changes into the cell of the target MN / SN.

[0102] If used Figure 5aIn an embodiment, and the target MN uses indirect forwarding, the source node (source MN) is unaware that there is a single target SN behind the target MN. The source node then forwards the same data to each target MN separately, and the target MN forwards it to the target SN. However, since the target SNs use the same target TEID and since the forwarded data is numbered in the case of intra-RAT HO, the target SN will be able to eliminate duplicated PDUs and maintain a single DL buffer. However, once the source node knows that there is a single target SN behind different target MNs (because the target MN applies direct forwarding or because the assigned TEIDs are shared, as described above), it is able to forward the data once instead of copying it through multiple paths. In this case, the source node can switch to forwarding the data through another target MN even if the target MN on which the data is forwarded is canceled (CHO is canceled there). Similarly, due to the PDU numbering and the single TEID at the target SN, the target SN will be able to assemble a single DL buffer.

[0103] The source node will understand when receiving the same TEID from multiple target MNs that there is a common destination for data forwarding and will forward the data only once. Finally, even if one or more target MNs prefer to use indirect forwarding, that is, packets for the target SN are first sent from the source node to the target MN, and the target MN then forwards them to the target SN, the target MN can also provide the target TEID from the target SN together with its own TEID. When the source node receives two TEIDs from the target node, the source node can identify the common destination for data forwarding by comparing the final TEID, so the source node can forward the data only through one of the prepared target MNs.

[0104] According to an embodiment, in order to avoid the SN being forced to manage the same data coming via different paths, the target SN merges or fills or queues the received data into the same data buffer or path end. When the target SN identifies that the add request is related to the preparation from another target MN (i.e., related to the same UE and the same SCG configuration is provided for the SN terminated bearer), the target SN allocates the same TEID for the add request.

[0105] When the target SN receives a data unit from any path (such as from other gNB / MN / SN), the target SN checks the target SN's data buffer to check whether the received data unit is already queued or otherwise available. If so, the target SN does not add the duplicate data unit to the data buffer or queue.

[0106] According to an embodiment, the detection and possible deletion of duplicate data units is performed in the network node before transmitting the data units to the UE via the air interface.

[0107] According to an embodiment, such repeated data units may also be detected in the UE.

[0108] Hereinafter, according to various embodiments, an enhanced method for conditional switching will be described in more detail.

[0109] This method is Figure 6a The flowchart is disclosed as reflecting the operation of an access node (such as an e / gNB), wherein the method includes: receiving (600) an add request by the access node from a target primary node together with an indication that the request involves a conditional handover, the request including an identifier of a user equipment and an identifier of a source primary node; if the access node has a control target primary cell prepared for the user equipment, using (602) the identifier of the user equipment and the identifier of the source primary node for verification; comparing (604) the existing secondary group configuration with the secondary group configuration included in the request; verifying (606) based on the comparison that the same data radio bearer can be allocated for the add request; and responding (608) to the request with an identifier of a tunnel endpoint for downlink data forwarding, which identifier has been allocated for a previous add request.

[0110] Another method is Figure 6b is disclosed in the flowchart as reflecting the source node (e.g., Figure 5a , Figure 5b or Figure 5c The method includes: receiving (620) a tunnel endpoint identifier of the first target MN and a first target tunnel endpoint identifier by the source node from the first target MN; receiving (622) a tunnel endpoint identifier of the second target MN and a second target tunnel endpoint identifier by the source node from the second target MN; determining (624) that the first target tunnel endpoint identifier and the second target tunnel endpoint identifier correspond to each other; and deciding (626) to send data addressed to the target SN via only one of the first target MN and the second target MN.

[0111] Therefore, in order to let the target SN know that the preparation requests received from different MNs involve the same UE, the identifier of the UE involved in the conditional switching process will be provided to the target SN. For example, when initiating the CHO process, the identifier can be assigned by the source MN or the source SN. The identifier is shared by all potential target MNs, so when receiving requests to be included in the CHO process as secondary nodes from multiple MNs, the access node can immediately determine whether multiple (i.e., two or more) requests involve the same UE based on the UE identifier included in the request. Therefore, when determining that multiple CHO preparation requests involve the same UE, the access node can optimize its radio resource reservation when initiating its operation as a target SN.

[0112] According to an embodiment, the identity of the user equipment is unique between the master nodes.

[0113] Therefore, when the source MN or source SN assigns an identity to a UE, the identity will be shared with all potential target MNs. Therefore, when dealing with any given target SN, all target MNs will be bound to use the same identity. In order to tell the difference between UEs associated with requests from MNs, and to identify requests related to the same UE, the identity of the UE should be unique among all target MNs involved in the CHO preparation.

[0114] According to an embodiment, the identity of the user equipment is temporary so that its validity depends on the preparation time of the conditional handover procedure.

[0115] Since the purpose of the UE's identity is to facilitate the access node's radio resource reservation process when the access node initiates its operation as the target SN in the CHO process, only a temporary identity is required for the UE. The validity period of the UE's identity can be set to be slightly longer than the maximum CHO preparation time, for example.

[0116] According to an embodiment, the identity of the user equipment is obtained from receiving an add request from the autonomous node. As part of the dual connectivity handover process, the target MN sends an add request to the potential target SN to notify it to prepare for CHO. Now, the identity of the UE can be included in this existing request message sent from the target MN to the target SN.

[0117] According to an embodiment, the identifier of the user equipment includes the identifier of the secondary node of the current serving node of the user equipment contained in the adding request.

[0118] This embodiment Figure 8a It should be noted that Figure 8a Only the initial phase of CHO preparation signaling is shown. Based on, for example, measurement reports from the UE, the source MN sends a conditional handover request to two potential target MNs, namely target MN 1 and target MN 2. The two potential target MNs, namely target MN 1 and target MN 2, send an add request to the access node, namely the target SN. The add request includes an Xn UE AP ID, which uniquely identifies the logical connection associated with the UE over the Xn interface within the M-NG-RAN node (i.e., the source SN in this case) for dual connectivity, as defined in 3GPP 38.401 Release-16.

[0119] Now, the identifier of the secondary node of the current serving node of the user equipment, ie the identifier of the current source SN of the UE (source SN ID), is provided to the Xn UE AP ID in the add request, which enables the target SN to uniquely identify the associated UE together with the Xn UE AP ID.

[0120] According to an embodiment, the identification of the user equipment further includes an identification of a current serving node of the user equipment included in the adding request.

[0121] Therefore, in addition to the identifier of the secondary node of the current serving node of the user equipment (ie, the source SN ID), the add request also provides the identifier of the current serving node of the user equipment and the identifier of the current source MN of the UE (source MN ID). Figure 8b The signaling diagram is shown in FIG. , which is similar to Figure 8a The signaling diagram is the same as above, but the add request also includes the source MN ID.

[0122] According to an embodiment, the identification of the user equipment includes an identification of a current serving node of the user equipment and an identification of the user equipment in the current serving node of the user equipment, both of which are included in the adding request.

[0123] Therefore, if the source MN uses the same Xn UE AP Id on all interfaces, the identity of the user equipment includes the source MN ID and the Xn UE AP ID allocated in the source MN ID, both of which are included in the add request. In other words, the add request is provided with the identity of the current serving node of the user equipment, i.e., the source MN ID and the Xn UE AP ID allocated in the current serving node of the user equipment.

[0124] According to an embodiment, the identification of the user equipment includes: a random number generated by a current serving node of the user equipment or a secondary node of the current serving node of the user equipment and included in the adding request.

[0125] Thus, the random number may be assigned to the UE at the source MN or source SN, unlike the source SN ID and possibly the source MN ID. The random number as UE ID may be passed to all prepared target MNs, which then include it in the add request to the selected target SN. If a target SN receives the same number from different MNs, it may assume that it relates to the same UE.

[0126] The conditional handover request sent by the source MN to the target MN and the add request sent by the target MN to the target SN include the updated SCG configuration provided with a random number as a temporary UE ID.

[0127] It should be noted that all the above solutions lead to the situation where the target SN is able to identify requests coming from different target MNs but concerning the same UE.

[0128] Methods and embodiments related thereto may also be implemented in an apparatus implementing an access point or base station (such as an eNB or gNB) of a radio access network. According to one aspect, an apparatus such as a gNB includes: a component for receiving requests from multiple primary nodes to be included as a secondary node in a part of a conditional handover process of a user equipment; a component for obtaining an identification of a user equipment involved in the conditional handover process from each of the requests; and a component for determining that multiple requests involve the same user equipment based on the identification of the user equipment.

[0129] According to an embodiment, the identity of the user equipment is unique between the master nodes.

[0130] According to an embodiment, the identity of the user equipment is temporary, so that its validity depends on the preparation time of the conditional handover procedure.

[0131] According to an embodiment, the apparatus comprises means for obtaining an identification of a user equipment from receiving an add request from a master node.

[0132] According to an embodiment, the identification of the user equipment includes an identification of a secondary node of a current serving node of the user equipment, and the identification is included in the adding request.

[0133] According to an embodiment, the identification of the user equipment further includes an identification of a current serving node of the user equipment included in the adding request.

[0134] According to an embodiment, the identification of the user equipment includes a random number generated by a current serving node of the user equipment or a secondary node of the current serving node of the user equipment, and the random number is included in the adding request.

[0135] According to an embodiment, the apparatus comprises: a component for generating a temporary identity configured for a secondary cell group; and a component for including the temporary identity configured for the secondary cell group in a confirmation message to be sent to one or more master nodes among a plurality of master nodes.

[0136] According to an embodiment, the apparatus comprises: a component for obtaining a request to release radio resources reserved by the apparatus for the user equipment from at least one of the master nodes in response to the master node receiving a conditional handover cancellation request from a current serving node of the user equipment.

[0137] According to an embodiment, the conditional handover cancellation request includes a temporary identifier configured for the secondary cell group.

[0138] According to another aspect, an apparatus such as an access point or base station (e.g., eNB or gNB) of a radio access network includes at least one processor and at least one memory, on which computer program code is stored, and the at least one memory and the computer program code are configured to use the at least one processor to cause the apparatus to at least perform: receiving requests from multiple primary nodes to be included as secondary nodes in a part of a conditional switching process of a user equipment; obtaining an identification of a user equipment involved in the conditional switching process from each of the requests; and determining, based on the identification of the user equipment, that multiple requests involve the same user equipment.

[0139] Such means may include, for example Figure 7 The functional unit disclosed in Figure 7 FIG. 1 is a simplified block diagram of a network node (ie, the device) according to various aspects and related embodiments. It should be noted that although the above embodiments are mainly disclosed in conjunction with a target secondary base station (SN), Figure 7 The disclosed structures and functional units are equally applicable to network nodes, such as source MN, source SN and target MN, etc., as described above.

[0140] The network node 1100 may be a base station, an access point, an access node, a gNB, an evolved Node B (eNB), a server, a host, or any other network entity that may communicate with a UE.

[0141] The apparatus may include at least one processor or control unit or module 1102. At least one memory 1104 may be provided in the apparatus. The memory may include computer program instructions or computer code contained therein. One or more transceivers 1106 may be provided, and the apparatus may also include an antenna 1108, although only one antenna is shown, many antennas and multiple antenna elements may be provided to the apparatus. For example, other configurations of the apparatus may be provided. For example, in addition to wireless communication, the network node may also be configured for wired communication with the UE, and in this case, the antenna 1108 may show any form of communication hardware, not limited to only an antenna.

[0142] Transceiver 1106 can be a transmitter, a receiver, or both a transmitter and a receiver, or a unit or device that can be configured for sending and receiving. Transmitters and / or receivers (as well as related radio components) can also be implemented as remote radio heads, which are not located in the device itself, but in the mast. Operations and functions can be performed in different entities such as nodes, hosts, or servers in a flexible manner. In other words, the division of labor can vary by situation. A possible use is to enable network nodes to deliver local content. One or more functions can also be implemented as virtual applications in software that can run on a server.

[0143] In some embodiments, the apparatus may include at least one processor and at least one memory including computer program code. The at least one memory including the computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform any of the processes described in this specification.

[0144] The processor 1102 may be embodied by any computing or data processing device, such as a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), a digital enhancement circuit, or the like, or a combination thereof. The processor may be implemented as a single controller or multiple controllers or processors.

[0145] For firmware or software, the implementation may include modules or units of at least one chipset (e.g., processes, functions, etc.). At least one memory 1104 may independently be any suitable storage device, such as a non-transitory computer-readable medium. A hard disk drive (HDD), random access memory (RAM), flash memory, or other suitable memory may be used. The memory may be combined on a single integrated circuit as a processor, or it may be separated from it. In addition, computer program instructions may be stored in the memory and may be processed by the processor in any suitable form of computer program code, such as a compiled or interpreted computer program written in any suitable programming language. The memory or data storage entity is typically internal, but may also be external or a combination thereof, such as in the case of obtaining additional memory capacity from a service provider. The memory may be fixed or removable.

[0146] The memory and computer program instructions may be configured to cause a hardware device such as network node 1100 to perform any of the above processes using a processor for a particular device. Thus, in some embodiments, a non-transitory computer-readable medium may be encoded with instructions or one or more computer programs (such as added or updated software routines, applets, or macros) that, when executed in hardware, may perform a process such as one of the processes described herein. In other embodiments, a computer program product may encode instructions for performing any of the above processes, or a computer program product embodied in a non-transitory computer-readable medium and encoding instructions that, when executed in hardware, perform any of the above processes. The computer program may be encoded in a programming language, which may be a high-level programming language such as objective-C, C, C++, C#, Java, etc., or a low-level programming language such as a machine language or assembler. Alternatively, some embodiments may be performed entirely in hardware.

[0147] According to an embodiment, a computer program includes instructions stored thereon, which are used to cause a device to perform at least the following operations: receive an add request from a target master node together with an indication that the request involves a conditional switch, the request including an identifier of a user equipment and an identifier of a source master node; if the device has a control target master cell prepared for the user equipment, use the identifier of the user equipment and the identifier of the source master node for verification and checking; compare the existing secondary group configuration with the secondary group configuration included in the request; based on the comparison, verify that the same data radio bearer can be allocated for the add request; respond to the request using an identifier of a tunnel endpoint for downlink data forwarding, the identifier having been allocated for a previous add request.

[0148] According to an embodiment, a computer program includes instructions stored thereon, which are used to cause a device to perform at least the following operations: receive a tunnel endpoint identifier of a first target master node and a first target tunnel endpoint identifier from a first target master node; receive a tunnel endpoint identifier of a second target master node and a second target tunnel endpoint identifier from a second target master node; determine that the first target tunnel endpoint identifier and the second target tunnel endpoint identifier correspond to each other; and decide to send data addressed to a target secondary node via only one of the first target master node and the second target master node.

[0149] According to an embodiment, a computer program includes instructions stored thereon, which are used to cause a device to perform at least the following operations: sending an add request related to conditional switching to a target secondary node, the add request including information about the requested secondary cell group bearer configuration and information about the identity of the user equipment; receiving an add request confirmation from the target secondary node, the add request confirmation including the secondary cell group configuration and an indication that an identifier of a tunnel endpoint allocated by the target secondary node for downlink data is shared with other target primary nodes; deciding to use indirect data forwarding based on the indication; and sending an identifier of the tunnel endpoint of the device and a shared identifier of the tunnel endpoint allocated by the target secondary node for downlink data to a source primary node.

[0150] In some embodiments, the device may include a circuit system configured to perform any of the above-mentioned processes or functions. In one example, the circuit system may be a hardware circuit implementation only, such as an analog and / or digital circuit system. In another example, the circuit system may be a combination of hardware circuits and software, such as a combination of (multiple) analog and / or digital hardware circuits with software or firmware, and / or any portion of (multiple) hardware with software (including (multiple) digital signal processors), software, and at least one memory, which work together to enable the device to perform various processes or functions. In yet another example, the circuit system may be (multiple) hardware circuits and / or (multiple) processors, such as (multiple) microprocessors or a portion of (multiple) microprocessors, including software (such as firmware for operation). When the operation of the hardware is not required, the software in the circuit system may not exist.

[0151] Specific examples of circuit systems may be content encoding circuit systems, content decoding circuit systems, processing circuit systems, image generation circuit systems, data analysis circuit systems, or discrete circuit systems. The term "circuitry" may also refer to, for example, a baseband integrated circuit or a processor integrated circuit for a mobile device, a network entity, or a similar integrated circuit in a server, a cellular network device, or other computing or network device.

[0152] On the other hand, a computer program product is stored on a non-volatile storage medium, the computer program product comprising computer program code, which, when executed by at least one processor, causes an apparatus to at least perform: receiving requests to be added as secondary nodes from multiple primary nodes as part of a conditional switching process for a user device; obtaining an identification of a user device involved in the conditional switching process from each of the requests; and determining, based on the identification of the user device, that multiple of the requests involve the same user device.

[0153] In general, various embodiments of the present invention may be implemented in hardware or dedicated circuits or any combination thereof. Although various aspects of the present invention may be illustrated and described as block diagrams or using some other graphical representations, it should be understood that these blocks, devices, systems, techniques or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general purpose hardware or controllers or other computing devices, or some combination thereof as non-limiting examples.

[0154] Embodiments of the present invention may be implemented in various components such as integrated circuit modules. The design of integrated circuits is generally a highly automated process. Complex and powerful software tools are available to convert a logic level design into a semiconductor circuit design that is ready to be etched on a semiconductor substrate.

[0155] Programs such as those provided by Synopsys Inc. of Mountain View, Calif., and Cadence Design of San Jose, Calif., automatically route conductors and position components on a semiconductor chip using established design rules and a library of pre-stored design modules. Once a design for a semiconductor circuit is complete, the resulting design can be transmitted in a standardized electronic format (e.g., Opus, GDSII, etc.) to a semiconductor fabrication facility or fabrication "fab" for fabrication.

[0156] The above description provides a complete and informative description of exemplary embodiments of the present invention by way of exemplary and non-limiting examples. However, in view of the above description, when read in conjunction with the accompanying drawings and the accompanying examples, various modifications and adjustments may be apparent to those skilled in the relevant art. However, all of these and similar modifications of the present invention's teachings will still fall within the scope of the present invention.

Claims

1. An apparatus, comprising at least one processor and at least one memory, wherein the at least one memory stores computer program code, wherein the at least one memory and the computer program code are configured to use the at least one processor to cause the apparatus to at least perform: receiving, from the target master node, an add request together with an indication that the request relates to a conditional switch, the request comprising an identifier of the user equipment and an identifier of the source master node; If the apparatus has a control target primary cell prepared for the user equipment, verifying using the identifier of the user equipment and the identifier of the source primary node; comparing the existing secondary group configuration with the secondary group configuration included in the request; based on the comparison, verifying that the same data radio bearer can be allocated for the add request; as well as The request is responded to with an identifier of a tunnel endpoint for downlink data forwarding, the identifier having been assigned for a previous add request.

2. The apparatus according to claim 1, comprising computer program code configured to cause the apparatus to execute: identifying that the add request is associated with a preparation from another master node; and The same identifier of the tunnel endpoint is assigned for the add request.

3. The apparatus according to claim 1 or 2, comprising computer program code, wherein the computer program code is configured to cause the apparatus to execute: If there is a matching add request, responding to the add request of the target primary node by including an indication in an add request confirmation message that the target secondary node will share the assigned identifier of the tunnel endpoint for downlink data forwarding with any other target primary node.

4. The apparatus according to claim 3, comprising computer program code configured to cause the apparatus to determine the matching add request by: Check whether the adding request includes the same user equipment identifier and the same secondary cell group configuration.

5. The apparatus according to any one of claims 1 to 4, comprising computer program code, wherein the computer program code is configured to cause the apparatus to execute: Allocating only a single buffer for downlink data; and The identifier of the tunnel endpoint is associated with the single buffer.

6. A method, include: receiving, from the target master node, an add request together with an indication that the request relates to a conditional switch, the request comprising an identifier of the user equipment and an identifier of the source master node; If the apparatus has a control target primary cell prepared for the user equipment, verifying using the identifier of the user equipment and the identifier of the source primary node; comparing the existing secondary group configuration with the secondary group configuration included in the request; based on the comparison, verifying that the same data radio bearer can be allocated for the add request; as well as The request is responded to with an identifier of a tunnel endpoint for downlink data forwarding, the identifier having been assigned for a previous add request.

7. An apparatus, comprising at least one processor and at least one memory, wherein the at least one memory has computer program code stored thereon, wherein the at least one memory and the computer program code are configured to use the at least one processor to cause the apparatus to at least perform: receiving, from a first target master node, a tunnel endpoint identifier of the first target master node and a first target tunnel endpoint identifier; receiving, from a second target master node, a tunnel endpoint identifier of the second target master node and a second target tunnel endpoint identifier; determining that the first target tunnel endpoint identifier and the second target tunnel endpoint identifier correspond to each other; as well as It is decided to send data addressed to a target secondary node via only one of the first target primary node and the second target primary node.

8. The apparatus according to claim 7, comprising computer program code configured to cause the apparatus to perform: receiving two tunnel endpoint identifiers from one of the first target master node and the second target master node; comparing the two tunnel endpoint identifiers; Based on the comparing, identifying a common destination for forwarding the data; as well as Data destined for the common destination is forwarded through only one of the first destination master node and the second destination master node.

9. A method, include: The source node receives the tunnel endpoint identifier of the first target master node and the first target tunnel endpoint identifier from the first target master node; Receiving, by the source node, a tunnel endpoint identifier of the second target master node and a second target tunnel endpoint identifier from the second target master node; determining, by the source node, that the first target tunnel endpoint identifier and the second target tunnel endpoint identifier correspond to each other; as well as It is determined by the source node to send data addressed to a target secondary node via only one of the first target primary node and the second target primary node.

10. An apparatus, comprising at least one processor and at least one memory, wherein the at least one memory has computer program code stored thereon, wherein the at least one memory and the computer program code are configured to use the at least one processor to cause the apparatus to at least perform: Sending an adding request involving conditional switching to a target secondary node, wherein the adding request includes information of the requested secondary cell group bearer configuration and information of an identity of a user equipment; receiving an add request confirmation from the target secondary node, the add request confirmation including a secondary cell group configuration and an indication that an identifier of a tunnel endpoint allocated by the target secondary node for downlink data is shared with other target primary nodes; Based on the instructions, decide to do one of the following: using indirect data forwarding and sending to a source primary node an identifier of a tunnel endpoint of the device and a shared identifier of the tunnel endpoint allocated by the target secondary node for downlink data; or Direct data forwarding is used and the shared identifier of the tunnel endpoint allocated by the target secondary node for downlink data is sent to the source primary node.

11. The apparatus according to claim 10, comprising computer program code configured to cause the apparatus to perform: generating a second conditional switching configuration; and The second conditional switching configuration includes the secondary cell group configuration.

12. The apparatus according to claim 11, comprising computer program code configured to cause the apparatus to perform: A handover request confirmation message is sent to the source MN, wherein the handover request confirmation message includes the second conditional handover configuration and the identifier of the tunnel endpoint of the device and the identifier of the tunnel endpoint of the target secondary node.

13. The apparatus according to any one of claims 10 to 12, comprising computer program code configured to cause the apparatus to execute: The packets are forwarded between the source primary node and the target secondary node without intercepting the packets.

14. A method, include: Sending an add request related to conditional switching to a target secondary node, wherein the add request includes information of the requested secondary cell group bearer configuration and information of the identity of the user equipment; receiving an add request confirmation from the target secondary node, the add request confirmation including a secondary cell group configuration and an indication that an identifier of a tunnel endpoint allocated by the target secondary node for downlink data is shared with other target primary nodes; determining to use indirect data forwarding based on the indication; An identifier of a tunnel endpoint of the device and the shared identifier of the tunnel endpoint allocated by the target secondary node for downlink data are sent to a source primary node.

15. A computer program comprising instructions stored thereon, the instructions being configured to cause an apparatus to at least perform the following operations: receiving, from a target master node, an add request together with an indication that the request relates to a conditional switch, the request comprising an identifier of the user equipment and an identifier of the source master node; If the apparatus has a control target primary cell prepared for the user equipment, verifying using the identifier of the user equipment and the identifier of the source primary node; comparing the existing secondary group configuration with the secondary group configuration included in the request; based on the comparison, verifying that the same data radio bearer can be allocated for the add request; as well as The request is responded to with an identifier of a tunnel endpoint for downlink data forwarding, the identifier having been assigned for a previous add request.

16. A computer program comprising instructions stored thereon, the instructions being configured to cause an apparatus to at least perform the following operations: receiving, from a first target master node, a tunnel endpoint identifier of the first target master node and a first target tunnel endpoint identifier; receiving, from a second target master node, a tunnel endpoint identifier of the second target master node and a second target tunnel endpoint identifier; determining that the first target tunnel endpoint identifier and the second target tunnel endpoint identifier correspond to each other; as well as It is decided to send data addressed to a target secondary node via only one of the first target primary node and the second target primary node.

17. A computer program comprising instructions stored thereon for performing at least the following operations: Sending an add request related to conditional switching to a target secondary node, wherein the add request includes information of the requested secondary cell group bearer configuration and information of the identity of the user equipment; receiving an add request confirmation from the target secondary node, the add request confirmation including a secondary cell group configuration and an indication that an identifier of a tunnel endpoint allocated by the target secondary node for downlink data is shared with other target primary nodes; determining to use indirect data forwarding based on the indication; An identifier of a tunnel endpoint of the device and the shared identifier of the tunnel endpoint allocated by the target secondary node for downlink data are sent to a source primary node.

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