System and method for successful handover reporting

Abstract

The invention provides a system and a method for successful handover reporting. A wireless communication node may receive a first radio resource configuration (RRC) message from a wireless communication device, the first RRC message including an indication that a successful handover report (SHR) is available at the wireless communication device, and an indication of a radio access technology (RAT) type associated with the SHR. The wireless communication node may receive a second RRC message from the wireless communication device, the second RRC message including the SHR and the first information.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications, including but not limited to systems and methods for successful handover reporting. Background Art

[0002] The Third Generation Partnership Project (3GPP), a standardization organization, is currently specifying a new air interface called 5G New Radio (5G NR) and the Next Generation Packet Core Network (NG-CN or NGC). 5GNR will have three main parts: 5G Access Network (5G-AN), 5G Core Network (5G GC) and User Equipment (UE). In order to facilitate the implementation of different data services and requirements, the network elements (also called network functions) of 5GC have been simplified, some of which are software-based and some are hardware-based, so that these network elements can be adjusted as needed. Summary of the invention

[0003] The example embodiments disclosed herein are directed to solving problems related to one or more problems existing in the prior art, as well as providing additional features, which will become apparent when referring to the detailed description below in conjunction with the accompanying drawings. According to various embodiments, example systems, methods, devices, and computer program products are disclosed herein. However, it should be understood that these embodiments are provided by way of example and not limitation, and it will be apparent to those of ordinary skill in the art who have read this disclosure that various modifications may be made to the disclosed embodiments (e.g., including combining features from various disclosed examples, embodiments, and / or implementations) without departing from the scope of this disclosure.

[0004] At least one aspect relates to the following systems, methods, apparatuses, or computer-readable media. A wireless communication node (e.g., an NG-RAN node) may receive a first Radio Resource Configuration (RRC) message from a wireless communication device (e.g., a UE), the first RRC message including: an indication that a Successful Handover Report (SHR) is available (e.g., generated, stored) at the wireless communication device, and an indication of a type of Radio Access Technology (RAT) associated with the SHR. The wireless communication node may receive a second RRC message from the wireless communication device, the second RRC message including the SHR and the first information.

[0005] In some embodiments, the first information may include at least one of the following: an indication of a RAT type associated with the SHR, or second information of at least one node that triggers the SHR, and the second information may include at least one of the following: a source cell global identity (CGI) of the handover associated with the SHR, a target cell global identity (CGI) of the handover, a source new generation radio access node (NG-RAN) node identifier (ID) or a source enhanced NodeB (eNB) ID of the handover, a source tracking area (TA) of the handover, a target NG-RAN node ID or a target eNB ID of the handover, a target TA of the handover, a triggered CGI of a cell configured with a satisfied SHR triggering condition, or a triggered NG-RAN node ID or eNBID associated with a cell configured with a triggering condition.

[0006] In some embodiments, the wireless communication node may determine a first target node to which the SHR will be sent. According to the second information, the first target node may be a source node or a target node of a handover associated with the SHR, or a triggered node associated with a cell configured with a satisfied SHR triggering condition. The wireless communication node may send an Xn Application Protocol (XnAP) message to the first target node, the XnAP message including at least one of: an SHR in a Long Term Evolution (LTE) format or a 5G New Radio (NR) format; a source cell radio network temporary identifier (C-RNTI); or mobility information.

[0007] In some embodiments, the SHR may be encoded according to the RAT type of the node configured with at least one condition for triggering the SHR. The wireless communication node may send a New Generation Application Protocol (NGAP) message to a core network (e.g., 5GC) for sending the SHR to the first target node through the core network, the NGAP message including at least one of the following: an SHR in LTE format or 5GNR format; a source C-RNTI; or mobility information. The core network may send at least one NGAP message to the first target node, the at least one NGAP message including at least one of the following: an SHR in LTE format or 5GNR format; a C-RNTI; or mobility information.

[0008] In some embodiments, the wireless communication node or the first target node may include a centralized unit (CU). The CU may send an F1 Application Protocol (F1AP) message to a distributed unit (DU) of the wireless communication node or the first target node, the F1AP message including at least one of the following: an SHR in an LTE format or a 5GNR format; a C-RNTI; or mobility information. The wireless communication node may send an X2 Application Protocol (X2AP) message to the first target node, the X2AP message including at least one of the following: an SHR in an LTE format or a 5GNR format; a source C-RNTI; or mobility information.

[0009] In some embodiments, the wireless communication node may send an S1 Application Protocol (S1AP) message to the first core network of LTE to send an SHR to the first target node through the first core network and the second core network (e.g., 5GC), the S1AP message including at least one of the following: an SHR in an LTE format or a 5GNR format; a source C-RNTI; or mobility information. The second core network may send an NGAP message to the first target node, the NGAP message including at least one of the following: an SHR in an LTE format or a 5GNR format; a C-RNTI; or mobility information.

[0010] In some embodiments, a wireless communication device (e.g., a UE) may send a first RRC message to a wireless communication node (e.g., an NG-RAN node), the first RRC message including: an indication that an SHR is available at the wireless communication device, and an indication of a RAT type associated with the SHR. The wireless communication device may send a second RRC message to the wireless communication node, the second RRC message including the SHR and the first information. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Various example embodiments of the present solution are described in detail below with reference to the following figures. The figures are provided for illustrative purposes only and only describe example embodiments of the present solution to facilitate the reader's understanding of the present solution. Therefore, the figures should not be regarded as limiting the breadth, scope or applicability of the present solution. It should be noted that for clarity and ease of description, these figures are not necessarily drawn to scale.

[0012] Figure 1 An example cellular communication network in which the techniques disclosed herein may be implemented according to an embodiment of the present disclosure is shown;

[0013] Figure 2 A block diagram showing an example base station and user equipment according to some embodiments of the present disclosure is shown;

[0014] Figure 3 A sequence diagram showing successful handover reporting according to some embodiments of the present disclosure is shown;

[0015] Figure 4 A sequence diagram showing successful handover reporting according to some embodiments of the present disclosure is shown;

[0016] Figure 5 A sequence diagram showing successful handover reporting according to some embodiments of the present disclosure is shown;

[0017] Figure 6 A sequence diagram showing successful handover reporting according to some embodiments of the present disclosure is shown;

[0018] Figure 7 A sequence diagram showing successful handover reporting according to some embodiments of the present disclosure; and

[0019] Figure 8 A flow chart of successful switching reporting according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0020] 1. Mobile Communication Technology and Environment

[0021] Figure 1An example wireless communication network and / or system 100 is shown in which the techniques disclosed herein may be implemented according to an embodiment of the present disclosure. In the following discussion, the wireless communication network 100 may be any wireless network, such as a cellular network or a narrowband Internet of Things (NB-IoT) network, and is referred to herein as "network 100". Such an example network 100 includes a base station (BS) 102 (hereinafter referred to as "BS 102"; also referred to as a wireless network node) and a user equipment device 104 (hereinafter referred to as "UE 104"; also referred to as a wireless communication device), which may communicate with each other via a communication link 110 (e.g., a wireless communication channel) and a cluster of cells 126, 130, 132, 134, 136, 138, and 140 covering a geographic area 101. In Figure 1 1, BS 102 and UE 104 are contained within respective geographic boundaries of cell 126. Each of the other cells 130, 132, 134, 136, 138, and 140 may include at least one base station operating over an allocated bandwidth to provide adequate wireless coverage to its intended users.

[0022] For example, BS 102 may operate on an allocated channel transmission bandwidth to provide adequate coverage to UE 104. BS 102 and UE 104 may communicate via downlink radio frames 118 and uplink radio frames 124, respectively. Each radio frame 118 / 124 may be further divided into subframes 120 / 127 that may include data symbols 122 / 128. In the present disclosure, BS 102 and UE 104 are generally described herein as non-limiting examples of "communication nodes" that may practice the methods disclosed herein. According to various embodiments of the present solution, such communication nodes may be capable of wireless and / or wired communications.

[0023] Figure 2 A block diagram of an example wireless communication system 200 for sending and receiving wireless communication signals (e.g., OFDM / OFDMA signals) according to some embodiments of the present solution is shown. The system 200 may include components and elements configured to support known or conventional operating features that need not be described in detail herein. In an illustrative embodiment, the system 200 may be used in applications such as Figure 1 Data symbols are communicated (eg, sent and received) in the wireless communication environment 100 of the wireless communication environment, as described above.

[0024] System 200 generally includes a base station 202 (hereinafter referred to as "BS 202") and a user equipment device 204 (hereinafter referred to as "UE 204"). BS 202 includes a BS (base station) transceiver module 210, a BS antenna 212, a BS processor module 214, a BS memory module 216, and a network communication module 218, each of which is coupled and interconnected to each other via a data communication bus 220 as necessary. UE 204 includes a UE (user equipment) transceiver module 230, a UE antenna 232, a UE memory module 234, and a UE processor module 236, each of which is coupled and interconnected to each other via a data communication bus 240 as necessary. BS 202 communicates with UE 204 via a communication channel 250, which can be any wireless channel or other medium suitable for data transmission as described herein.

[0025] As those skilled in the art will appreciate, the system 200 may also include Figure 2 , any number of modules outside the modules shown in . It will be appreciated by those skilled in the art that the various illustrative blocks, modules, circuits, and processing logic described in conjunction with the embodiments disclosed herein can be implemented with hardware, computer-readable software, firmware, or any actual combination thereof. In order to clearly illustrate this interchangeability and compatibility of hardware, firmware, and software, it is usually described according to the functionality of various illustrative components, frames, modules, circuits, and steps. Whether this functionality is implemented as hardware, firmware, or software can depend on the specific application and design constraints imposed on the entire system. Personnel familiar with the concepts described herein can implement such functionality in a suitable manner for each specific application, but such implementation decisions should not be interpreted as limiting the scope of the present disclosure.

[0026] According to some embodiments, the UE transceiver 230 may be referred to herein as an "uplink" transceiver 230, which includes a Radio Frequency (RF) transmitter and an RF receiver, each of which includes a circuit system coupled to an antenna 232. A duplex switch (not shown) may alternatively couple the uplink transmitter or receiver to the uplink antenna in a time duplex manner. Similarly, according to some embodiments, the BS transceiver 210 may be referred to herein as a "downlink" transceiver 210, which includes an RF transmitter and an RF receiver, each of which includes a circuit system coupled to an antenna 212. The downlink duplex switch may alternatively couple the downlink transmitter or receiver to the downlink antenna 212 in a time duplex manner. The operation of the two transceiver modules 210 and 230 may be coordinated in time such that while the downlink transmitter is coupled to the downlink antenna 212, the uplink receiver circuit system is coupled to the uplink antenna 232 to receive transmissions via the wireless transmission link 250. Conversely, the operations of the two transceivers 210 and 230 may be coordinated in time such that while the uplink transmitter is coupled to the uplink antenna 232, the downlink receiver is coupled to the downlink antenna 212 to receive transmissions via the wireless transmission link 250. In some embodiments, there is strict time synchronization with a minimum guard time between duplex direction changes.

[0027] The UE transceiver 230 and the base station transceiver 210 are configured to communicate via a wireless data communication link 250 and cooperate with an appropriately configured RF antenna arrangement 212 / 232 that can support a specific wireless communication protocol and modulation scheme. In some illustrative embodiments, the UE transceiver 210 and the base station transceiver 210 are configured to support industry standards such as Long Term Evolution (LTE) and emerging 5G standards. However, it should be understood that the present disclosure is not necessarily limited to the application of specific standards and related protocols. Instead, the UE transceiver 230 and the base station transceiver 210 can be configured to support alternative or additional wireless data communication protocols, including future standards or variations thereof.

[0028] According to various embodiments, BS 202 may be, for example, an evolved Node B (eNB), a serving eNB, a target eNB, a femtocell or a microcell. In some embodiments, UE 204 may be implemented in various types of user devices (such as mobile phones, smart phones, personal digital assistants (PDAs), tablet computers, laptop computers, wearable computing devices, etc.). Processor modules 214 and 236 may be implemented or implemented using a general purpose processor, a content addressable memory, a digital signal processor, an application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination thereof designed to perform the functions described herein. In this way, the processor may be implemented as a microprocessor, a controller, a microcontroller, a state machine, etc. The processor may also be implemented as a combination of computing devices, for example, a combination of a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in combination with a digital signal processor core, or any other such configuration.

[0029] In addition, the steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be directly implemented in hardware, firmware, software modules executed by the processor modules 214 and 236, respectively, or any practical combination thereof. The memory modules 216 and 234 may be implemented as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. In this regard, the memory modules 216 and 234 may be coupled to the processor modules 210 and 230, respectively, so that the processor modules 210 and 230 may read information from and write information to the memory modules 216 and 234, respectively. The memory modules 216 and 234 may also be integrated into their respective processor modules 210 and 230. In some embodiments, the memory modules 216 and 234 may each include a cache memory for storing temporary variables or other intermediate information during the execution of instructions to be executed by the processor modules 210 and 230, respectively. Memory modules 216 and 234 may also each include non-volatile memory for storing instructions to be executed by processor modules 210 and 230, respectively.

[0030] The network communication module 218 generally represents the hardware, software, firmware, processing logic and / or other components of the base station 202 that implements bidirectional communication between the base station transceiver 210 and other network components and the communication nodes configured to communicate with the base station 202. For example, the network communication module 218 can be configured to support Internet or WiMAX services. In a non-restrictive typical deployment, the network communication module 218 provides an 802.3 Ethernet interface so that the base station transceiver 210 can communicate with a conventional Ethernet-based computer network. In this way, the network communication module 218 can include a physical interface for connecting to a computer network (e.g., a mobile switching center (MSC)). The terms "configured for", "configured to" and variations thereof used herein for a specific operation or function refer to a device, component, circuit, structure, machine, signal, etc. that is physically constructed, programmed, formatted and / or arranged to perform a specified operation or function.

[0031] The Open Systems Interconnection (OSI) model (referred to herein as the "OSI model") is a concept and logical layout that defines network communications used by systems (e.g., wireless communication devices, wireless communication nodes) that are open to interconnection and communication with other systems. The model is divided into seven subcomponents or layers, each of which represents a conceptual set of services provided to its upper and lower layers. The OSI model also defines a logical network and effectively describes computer packet transmission by using different layer protocols. The OSI model may also be referred to as a seven-layer OSI model or a seven-layer model. In some embodiments, the first layer may be a physical layer. In some embodiments, the second layer may be a medium access control (MAC) layer. In some embodiments, the third layer may be a radio link control (RLC) layer. In some embodiments, the fourth layer may be a packet data convergence protocol (PDCP) layer. In some embodiments, the fifth layer may be a radio resource control (RRC) layer. In some embodiments, the sixth layer may be a Non Access Stratum (NSA) layer or an Internet Protocol (IP) layer, and the seventh layer is another layer.

[0032] Various example embodiments of the present solution are described below with reference to the accompanying drawings so that a person of ordinary skill in the art can derive and use the present solution. As will be apparent to a person of ordinary skill in the art, after reading this disclosure, various changes or modifications may be made to the examples described herein without departing from the scope of the present solution. Therefore, the present solution is not limited to the example embodiments and applications described and illustrated herein. In addition, the specific order or hierarchy of steps in the methods disclosed herein are merely example methods. Based on design preferences, the specific order or hierarchy of steps of the disclosed methods or processes may be rearranged while remaining within the scope of the present solution. Therefore, a person of ordinary skill in the art will understand that the methods and techniques disclosed herein present various steps or actions in an example order, and that the present solution is not limited to the specific order or hierarchy presented, unless otherwise expressly stated.

[0033] 2. System and method for reporting successful handoffs

[0034] For a successful handover (HO) from a gNB belonging to a source NR (e.g., 5GNR) cell to a Next-Generation Evolved Node B (NG-eNB) belonging to a target LTE cell, or a HO from an ng-eNB belonging to a source LTE cell to a gNB belonging to a target 5GNR cell, the UE may not generate an LTE format SHR. If the SHR triggering conditions configured by the eNB are met, the NG-RAN node receiving the SHR may not transmit an LTE format SHR to the associated node (e.g., source / target node) of the handover for mobility robustness optimization.

[0035] In 5G / 6G / other networks, one of the functions of mobility robustness optimization is to detect potential connection failures during a successful normal handover. The problem of a successful handover (HO) can be defined as follows. During a successful handover, some SHR triggering conditions can be met, which means that some problems may occur during the handover.

[0036] For a successful HO from a source NR (e.g., 5G NR) cell to a target NR cell, the network may configure an SHR trigger condition for the UE immediately prior to the handover. If the configured SHR trigger condition has been met during a successful handover with the target cell, the UE may generate an SHR. The UE may store the latest (or most recent) SHR until the network obtains / requests the SHR, or within 48 hours after the SHR is generated. The UE may indicate the availability of the SHR, and the network may obtain / request the SHR from the UE.

[0037] The SHR may be transmitted to the node configured with the triggered triggering condition. That is, if the SHR is triggered by at least one triggering condition configured by the source node, the SHR may be transmitted to the source node of the handover. Otherwise, the SHR may be transmitted to the target node of the handover. Therefore, the corresponding node may perform optimization based on the received SHR report.

[0038] In current 5G networks, the UE may only generate SHR for a successful HO from NG-RAN node 1 belonging to the source 5G NR cell to NG-RAN node 2 belonging to the target 5G NR cell. In other words, only intra-5G NRRAT SHR may be supported in current 5G networks.

[0039] In 5G / 6G / other networks, the NG-RAN node can be a gNB or ng-eNB. The gNB can provide 5G NRRAT user plane and control plane services to the UE. The ng-eNB can provide LTE RAT user plane and control plane protocol services to the UE. The gNB and ng-eNB can be connected to each other through (via) the Xn interface, and they can be connected to the 5GC through (via) the NG interface.

[0040] Implementation Example 1 (within 5GC): Previous inter-RAT SHR reporting via Xn interface

[0041] In this implementation example, a previous LTE RAT handover may have occurred. The UE may generate an SHR based on the RAT type (e.g., an LTE format SHR). However, the network may not (immediately) obtain this LTE SHR from the UE. After some time, the UE may successfully handover to the gNB, and the gNB may (at that time) obtain / request the previous SHR from the UE. The network may transmit the LTE SHR to the source / target ng-eNB associated with the HO SHR. Figure 3 Example message flows and interactions between UE, ng-eNB and gNB are shown.

[0042] In step 1, the ng-eNB may be an enhanced LTE eNodeB connected to the 5GC. Both eNB1 and eNB2 may be ng-eNBs. The gNB may be connected to the 5GC. The gNB and the ng-eNB may be connected to each other through (or via) an Xn interface.

[0043] In step 2, the UE may connect to NG-RAN node 1 (e.g., ng-eNB 1) providing LTE RAT services.

[0044] In step 3, after intra-RAT (e.g., LTE to LTE) handover, the UE may connect with a NG-RAN node 2 (e.g., ng-eNB 2) providing LTE RAT services.

[0045] In step 4, the UE may generate an SHR, which may be encoded based on the RAT type of the node configured with the corresponding triggering condition that has been met. All SHR triggering conditions may be configured by ng-eNB 1 and / or ng-eNB 2. The UE may generate an LTE format SHR.

[0046] In step 5, after an inter-RAT (e.g., LTE to 5G NR) handover, the UE may handover from the ng-eNB 1 to the gNB. The UE may be connected to (e.g., may be connected to or connected with) an NG-RAN node 3 (e.g., a gNB) providing 5G NR RAT services. In some embodiments, the SHR triggering condition may not be met during the handover. Therefore, the UE does not generate a new SHR.

[0047] In step 6, the UE may send an RRC message (e.g., RRC establishment request, RRC reconfiguration request response, RRC recovery request and / or RRC reestablishment request response) to the NG-RAN node 3 (e.g., gNB) to notify that the SHR is available at the UE. The RRC message may include an SHR RAT type indication (e.g., LTE type or 5G NR type).

[0048] In step 7, the NG-RAN node 3 (e.g., gNB) may send an RRC message (e.g., UE Information Request) to the UE to obtain / request an SHR.

[0049] In step 8, the UE may send an RRC message (e.g., a UE information request response) to the NG-RAN node 3 (e.g., a gNB). The RRC message may include an SHR (LTE SHR format). The RRC message may include at least one of the following information: an indication of an LTE type RAT associated with the SHR, or second information of at least one node that triggers the SHR, the second information including at least one of the following information: a source CGI of the handover associated with the SHR, a target CGI of the handover, a source NG-RAN node ID or source eNB ID of the handover, a TA of the handover, a target NG-RAN node ID or target eNB ID of the handover, a target TA of the handover, a triggered CGI of a cell configured with a satisfied SHR triggering condition, or a triggered NG-RAN node ID or eNB ID associated with a cell configured with a triggering condition. The CGI may be an NR CGI or an LTE CGI. The TA of the handover shall uniquely identify the tracking area.

[0050] In step 9, the NG-RAN node 3 (e.g., gNB) may decide / determine the target node to which the SHR will be sent based on the SHR triggering node information. The target node may be a source node or a target node of a handover associated with the SHR. In some embodiments, the target node may be a triggered node associated with a cell configured with a satisfied SHR triggering condition.

[0051] In step 10, the NG-RAN node 3 (e.g., gNB) may send an XnAP message (e.g., access and mobility indication) to the target node of the handover associated with the SHR (e.g., source NG-RAN node (ng-eNB 1)). The XnAP message may include an LTE format SHR.

[0052] In step 11, the NG-RAN node 3 (e.g., gNB) may send an XnAP message (e.g., access and mobility information) to the target node of the handover associated with the SHR (e.g., target NG-RAN node (ng-eNB 2)). The XnAP message may include an LTE format SHR.

[0053] Implementation Example 2 (within 5GC): Current Inter-RAT SHR reporting via Xn interface

[0054] In this implementation example, a current handover between an LTE RAT and a 5G NR RAT may have occurred. The UE may generate an SHR that is encoded based on the RAT type of the node that configures the corresponding triggering condition that has been met. In some embodiments, the UE may generate an LTE format SHR. The gNB (e.g., the target node of the handover) may obtain / request the current SHR from the UE. The gNB may transmit the LTE SHR to the source ng-eNB of the handover. Figure 4 Example message flows and interactions between UE, ng-eNB and gNB are shown.

[0055] In step 1, NG-RAN node 1 (e.g., eNB) can be an ng-eNB connected to 5GC and can provide LTE services. NG-RAN node 2 (e.g., gNB) can be connected to 5GC and can provide 5G services. NG-RAN node 1 and NG-RAN node 2 are connected to each other via an Xn interface.

[0056] In step 2, the UE may connect to NG-RAN node 1 (e.g., ng-eNB 1) providing LTE RAT services.

[0057] In step 3, after inter-RAT (e.g., LTE to 5G NR) switching, the UE can connect to the NG-RAN node 2 (e.g., gNB) providing 5G NR RAT services.

[0058] In step 4, the UE may generate an SHR, which may be encoded based on the RAT type of the node that configures the corresponding trigger condition. The UE may generate an LTE format SHR. In some embodiments, if the SHR trigger condition configured by the gNB is met, the UE may generate a 5G NR format SHR.

[0059] In step 5, the UE may send an RRC message (e.g., RRC establishment request, RRC reconfiguration request response, RRC recovery request and / or RRC reestablishment request response) to the NG-RAN node 2 (e.g., gNB) to notify that the SHR is available at the UE. The RRC message may include an SHR RAT type indication (e.g., LTE type or 5G NR type).

[0060] In step 6, the NG-RAN node 2 (e.g., gNB) may send an RRC message (e.g., UE Information Request) to the UE to obtain / request an SHR.

[0061] In step 7, the UE may send an RRC message (e.g., UE Information Request Response) to the NG-RAN node 2 (e.g., gNB). The RRC message may include an SHR (LTE SHR format). The RRC message may include at least one of the following information: an indication of an LTE type RAT associated with the SHR, or second information of at least one node that triggers the SHR, the second information including at least one of the following information: a source CGI of the handover associated with the SHR, a target CGI of the handover, a source NG-RAN node ID or source eNB ID of the handover, a TA of the handover, a target NG-RAN node ID or target eNB ID of the handover, a target TA of the handover, a triggered CGI of a cell configured with a satisfied SHR triggering condition, or a triggered NG-RAN node ID or eNB ID associated with a cell configured with a triggering condition. The CGI may be an NR CGI or an LTE CGI. The TA of the handover shall uniquely identify the tracking area.

[0062] In step 8, the NG-RAN node 2 (e.g., gNB) may be the target node for the handover. The gNB may decide / determine the target node to which the SHR will be sent based on the received SHR triggering node information. The target node may be the source node or the target node of the handover associated with the SHR. In some embodiments, the gNB may decide / determine the source node for the handover based on the UE context. If the target node (e.g., gNB) stores the UE context, the gNB may find out the source C-RNTI (to identify the UE in the source node) and / or mobility information in the handover request message.

[0063] In step 9, the NG-RAN node 2 (e.g., gNB) may send an XnAP message (e.g., access and mobility information) to the source NG-RAN node (e.g., ng-eNB) of the handover associated with the SHR. The XnAP message may include at least one of the following information: an SHR in LTE format or 5G NR format; a source C-RNTI; or mobility information. If the SHR generated by the UE in step 4 is in 5G NR format, the SHR format here may be in 5G NR format. The source C-RNTI may identify the UE in the source node / cell. The mobility information may help the source node identify suboptimal mobility parameters and perform possible adjustments.

[0064] Implementation Example 3 (within 5GC): Current Inter-RAT SHR reporting via 5GCNG interface (without Xn interface)

[0065] In this implementation example, a current handover between an LTE RAT and a 5G NR RAT may have occurred. The UE may generate an SHR that is encoded based on the RAT type of the node for which the corresponding trigger condition is configured to be met. In some embodiments, the UE may generate an LTE format SHR. NG-RAN node 1 (e.g., the target node of the handover) may obtain / request the current SHR from the UE. NG-RAN node 1 may transmit the LTE SHR to NG-RAN node 2 (e.g., the source node of the handover associated with the SHR). In some embodiments, there may be no Xn interface between NG-RAN node 1 and NG-RAN node 2. NG-RAN node 1 (e.g., the target node of the handover) may transmit the SHR to NG-RAN node 2 (e.g., the source node of the handover associated with the SHR) via 5GC. Figure 5 Example message flows and interactions between UE, NG-RAN nodes and 5GC are shown.

[0066] In step 1, NG-RAN node 1 may provide RAT type 1 services (e.g., LTE services). NG-RAN node 2 may provide RAT type 2 services (e.g., 5G NR services). NG-RAN node 1 and NG-RAN node 2 may be connected to 5GC. In some embodiments, there may be no Xn interface between NG-RAN node 1 and NG-RAN node 2.

[0067] In step 2, the UE may connect to NG-RAN node 1 (e.g., ng-eNB 1) providing LTE RAT services.

[0068] In step 3, after inter-RAT (e.g., LTE to 5G NR) switching via the NG interface, the UE can connect to the NG-RAN node 2 (e.g., gNB) providing 5G NR RAT services.

[0069] In step 4, the UE may generate an SHR, which may be encoded based on the RAT type of the node that configures the corresponding triggering condition. In some embodiments, if the SHR triggering condition configured by the ng-gNB is met, the UE may generate / output an LTE NR format SHR. In some embodiments, if the SHR triggering condition configured by the gNB is met, the UE may generate a 5G NR format SHR.

[0070] In step 5, the UE may send an RRC message (e.g., RRC establishment request, RRC reconfiguration request response, RRC recovery request and / or RRC reestablishment request response) to the NG-RAN node 2 (e.g., gNB) to notify that the SHR is available at the UE. The RRC message may include an SHR RAT type indication (e.g., LTE type or 5G NR type).

[0071] In step 6, the NG-RAN node 2 (e.g., gNB) may send an RRC message (e.g., UE Information Request) to the UE to obtain / request an SHR.

[0072] In step 7, the UE may send an RRC message (e.g., UE Information Request Response) to the NG-RAN node 2 (e.g., gNB). The RRC message may include an SHR (LTE SHR format). The RRC message may include at least one of the following information: an indication of an LTE type RAT associated with the SHR, or second information of at least one node triggering the SHR, the second information including at least one of the following information: a source CGI of the handover associated with the SHR, a target CGI of the handover, a source NG-RAN node ID or source eNB ID of the handover, a source TA of the handover, a target NG-RAN node ID or target eNB ID of the handover, a target TA of the handover, a triggered CGI of a cell configured with a satisfied SHR triggering condition, or a triggered NG-RAN node ID or eNB ID associated with a cell configured with a triggering condition. The CGI may be an NR CGI or an LTE CGI. The switched TA will uniquely identify the tracking area.

[0073] In step 8, the NG-RAN node 2 (e.g., gNB) may be the target node for the handover. The gNB may decide / determine the target node to which the SHR will be sent based on the received SHR triggering node information. The target node may be the source node or the target node of the handover associated with the SHR. In some embodiments, the gNB may decide / determine the source node for the handover based on the UE context. If the target node (e.g., gNB) stores the UE context, the gNB may find out the source C-RNTI (to identify the UE in the source node) and / or mobility information in the handover request message.

[0074] In step 9, since there is no Xn interface between the source node and the target node, the NG-RAN node can transmit the SHR to the source node of the handover associated with the SHR via the 5GC. The NG-RAN node 2 (e.g., gNB) can send an NGAP message (e.g., uplink RAN ​​configuration transmission) to the 5GC. The NGAP message may include at least one of the following: an SHR in LTE format or 5G NR format; a source C-RNTI; or mobility information. If the SHR generated by the UE in step 4 is in 5G NR format, the SHR format here may be in 5G NR format. The source C-RNTI can identify the UE in the source node / cell. The mobility information can help the source node identify suboptimal mobility parameters and perform possible adjustments.

[0075] In step 10, the 5GC may send an NGAP message (e.g., downlink RAN ​​configuration transmission) to the NG-RAN node 1 (e.g., ng-eNB). The NGAP message may include at least one of: an SHR in LTE format or 5G NR format; a source C-RNTI; or mobility information. If the SHR generated by the UE in step 4 is in 5G NR format, the SHR format here may be in 5G NR format. The source C-RNTI may identify the UE in the source node / cell. The mobility information may help the source node identify suboptimal mobility parameters and perform possible adjustments.

[0076] Implementation Example 4: SHR reporting via F1 interface (CU / DU case)

[0077] In this implementation example, the gNB-CU may transmit the SHR to the gNB-DU where the source cell or the target cell is located. Figure 6 Example message flows and interactions between the UE, gNB-CU, and gNB-DU are shown.

[0078] In step 1, the gNB may be a CU / DU separated gNB. The gNB-CU may be connected to the gNB-DU node via the F1 interface. The UE may be connected to the gNB.

[0079] In step 2, the gNB (e.g., gNB-CU) may receive SHR and / or SHR triggering node information from the UE or from other NG-RAN nodes.

[0080] In step 3, the gNB-CU may decide / determine in which gNB-DU the source cell or target cell of the handover associated with the SHR is located based on the received SHR triggering node information or based on the saved UE context. If the target node (e.g. gNB) saves the UE context, the gNB-CU may find out the source C-RNTI (to identify the UE in the source node) and / or mobility information in the handover request message.

[0081] In step 4, the gNB-CU may send an F1AP message (e.g., Access and Mobility Indication) to the gNB-DU. The F1AP may include at least one of: an SHR in LTE format or 5G NR format; a source C-RNTI; or mobility information. The source C-RNTI may identify the UE in the source node / cell. The mobility information may help the source node identify suboptimal mobility parameters and perform possible adjustments.

[0082] Implementation Example 5: eNB (LTE node) transmits SHR to NG-RAN node

[0083] Figure 7 Example message flows and interactions between UE, LTE nodes, NG-RAN nodes, LTE core network and 5GC are shown.

[0084] In step 1, the UE may have dual connectivity with an LTE node (e.g., eNB) and an NG-RAN node (e.g., gNB). The LTE node may act as a master node (MN). The NG-RAN node may act as a secondary node (SN). The LTE node may be connected to the NG-RAN node (e.g., gNB) via an X2 interface.

[0085] In step 2, an LTE node (eg, eNB) may receive SHR and / or SHR triggering node information from a UE.

[0086] In step 3, the LTE node may decide / determine the first target node to which the SHR will be sent based on the received SHR triggering node information. The first target node may be a source node or a target node of a handover associated with the SHR. In some embodiments, the first target node may be a triggered node associated with a cell configured with a satisfied SHR triggering condition.

[0087] Condition A: Non-standalone NG-RAN Node (SN) is either a source node or a target node

[0088] In step 4a-1, if the SN is the target node, the eNB / MN may send an X2AP message (e.g., access and mobility indication) to the NG-RAN node (e.g., SN). The X2AP may include at least one of: an SHR in LTE format or 5G NR format; a source C-RNTI; or mobility information. The source C-RNTI may identify the UE in the source node / cell. The mobility information may help the source node identify suboptimal mobility parameters and / or perform possible adjustments.

[0089] Condition B: Another independent NG-RAN node is the source node or the target node

[0090] In step 4b-1, if another independent NG-RAN node is the target node, the eNB may transmit the SHR to the NG-RAN node via the LTE core network and the 5GC. The eNB may send an S1AP message (e.g., eNB configuration transmission) to the LTE core network and the 5GC. The S1AP message may include at least one of: an SHR in LTE format or 5G NR format; a source C-RNTI; or mobility information. The source C-RNTI may identify the UE in the source node / cell. Mobility information may help the source node identify suboptimal mobility parameters and perform possible adjustments. The LTE core network may forward the received information to the 5GC via an S1AP message.

[0091] In step 4b-2, the 5GC may send an NGAP message (e.g., a downlink RAN ​​configuration transmission) to the NG-RAN node. The NGAP message may include at least one of: an SHR in LTE format or 5G NR format; a source C-RNTI; or mobility information. The source C-RNTI may identify the UE in the source node / cell. The mobility information may help the source node identify suboptimal mobility parameters and perform possible adjustments.

[0092] It should be understood that one or more features from the above-mentioned implementation examples are not exclusive of a specific implementation example, but can be combined in any manner (eg, in any priority and / or order, simultaneously or in other manners).

[0093] Figure 8 A flow chart of a method 800 for reporting successful handover is shown. The method 800 may be used in conjunction with Figure 1 to Figure 2 The method 800 may be implemented by any one or more components and devices described in detail. In summary, in some embodiments, the method 800 may be performed by a wireless communication node. Depending on the embodiment, additional, fewer or different operations may be performed in the method 800. At least one aspect of the operation relates to a system, method, apparatus or computer-readable medium.

[0094] A wireless communication node (e.g., an NG-RAN node) may receive a first RRC message from a wireless communication device (e.g., a UE), the first RRC message including: an indication that an SHR is available at the wireless communication device, and / or an indication of a RAT type associated with the SHR. The wireless communication node may receive a second RRC message from the wireless communication device, the second RRC message including the SHR and / or the first information.

[0095] In some embodiments, the first information may include at least one of the following: an indication of the RAT type associated with the SHR, or second information of at least one node that triggers the SHR, and the second information includes at least one of the following: a source CGI of the handover associated with the SHR, a target CGI of the handover, a source NG-RAN node ID or a source eNB ID of the handover, a source TA of the handover, a target NG-RAN node ID or a target eNB ID of the handover, a target TA of the handover, a triggered CGI of a cell configured with a satisfied SHR triggering condition, or a triggered NG-RAN node ID or an eNB ID associated with a cell configured with a triggering condition.

[0096] In some embodiments, the wireless communication node may determine a first target node to which the SHR is to be sent. Based on the second information, the first target node may be a source node or a target node of a handover associated with the SHR, or a triggered node associated with a cell configured with a satisfied SHR triggering condition. The wireless communication node may send an XnAP message to the first target node, the XnAP message including at least one of: an SHR in an LTE format or a 5G NR format; a source C-RNTI; or mobility information.

[0097] In some embodiments, the SHR may be encoded according to the RAT type of the node configured with at least one condition for triggering the SHR. The wireless communication node may send an NGAP message to the core network for sending the SHR to the first target node through the core network. The NGAP message may include at least one of the following: an SHR in LTE format or 5G NR format; a source C-RNTI; or mobility information. The core network may send at least one NGAP message to the first target node, the at least one NGAP message including at least one of the following: an SHR in LTE format or 5G NR format; a C-RNTI; or mobility information.

[0098] In some embodiments, the wireless communication node or the first target node may include a CU. The CU may send an F1AP message to the DU of the wireless communication node or the first target node, and the F1AP message includes at least one of the following: an SHR in an LTE format or a 5G NR format; a C-RNTI; or mobility information. The wireless communication node may send an X2AP message to the first target node. The X2AP message may include at least one of the following: an SHR in an LTE format or a 5G NR format; a source C-RNTI; or mobility information.

[0099] In some embodiments, the wireless communication node may send an S1AP message to the first core network of LTE to send an SHR to the first target node through the first core network and the second core network. The S1AP message may include at least one of the following: an SHR in LTE format or 5G NR format; a source C-RNTI; or mobility information. The second core network may send an NGAP message to the first target node, and the new generation NGAP message includes at least one of the following: an SHR in LTE format or 5G NR format; a C-RNTI; or mobility information.

[0100] In some embodiments, a wireless communication device (e.g., a UE) may send a first RRC message to a wireless communication node (e.g., an NG-RAN node), the first RRC message including: an indication that an SHR is available at the wireless communication device, and an indication of a RAT type associated with the SHR. The wireless communication device may send a second RRC message to the wireless communication node, the second RRC message including the SHR and the first information.

[0101] Although various embodiments of the present solution have been described above, it should be understood that these embodiments are presented only as examples and not as limitations. Similarly, various figures may depict example architectures or configurations, which are provided to enable those of ordinary skill in the art to understand the example features and functions of the present solution. However, these technicians will understand that the present solution is not limited to the example architectures or configurations shown, but may be implemented using various alternative architectures and configurations. Additionally, as will be appreciated by those of ordinary skill in the art, one or more features of an embodiment may be combined with one or more features of another embodiment described herein. Therefore, the breadth and scope of the present disclosure should not be limited by any of the above-described illustrative embodiments.

[0102] It should also be understood that any reference to an element using designations such as "first," "second," etc. herein generally does not limit the number or order of these elements. Rather, these designations may be used herein as a convenient means of distinguishing between two or more elements or instances of elements. Thus, a reference to a first element and a second element does not mean that only two elements can be used, or that the first element must precede the second element in some manner.

[0103] Additionally, it will be understood by those skilled in the art that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, and symbols (e.g., as may be referenced in the above description) may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0104] It will be further understood by those of ordinary skill in the art that any of the various illustrative logic blocks, modules, processors, devices, circuits, methods, and functions described in conjunction with the various aspects disclosed herein may be implemented by electronic hardware (e.g., digital implementation, analog implementation, or a combination of the two), firmware, various forms of programs or design codes in conjunction with instructions (which, for convenience, may be referred to herein as "software" or "software modules"), or any combination of these technologies. In order to clearly illustrate this interchangeability of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps have been described above in their entirety in terms of their functionality. Whether such functionality is implemented as hardware, firmware, or software, or a combination of these technologies, depends on the specific application and the design constraints imposed on the entire system. Those of ordinary skill in the art may implement the described functionality in various ways for each specific application, but such implementation decisions will not result in a departure from the scope of this disclosure.

[0105] In addition, it will be understood by those of ordinary skill in the art that the various illustrative logic blocks, modules, devices, components and circuits described herein may be implemented in or performed by an integrated circuit (IC), which may include a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device or any combination thereof. The logic blocks, modules and circuits may also include antennas and / or transceivers to communicate with various components within a network or within a device. The general purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a combination of multiple microprocessors, a combination of one or more microprocessors and a digital signal processor core, or any other suitable configuration to perform the functions described herein.

[0106] If implemented in software, the functions may be stored as one or more instructions or codes on a computer-readable medium. Therefore, the steps of the method or algorithm disclosed herein may be implemented as software stored on a computer-readable medium. Computer-readable media include computer storage media and communication media, and communication media include any media that can realize the transfer of computer programs or codes from one place to another. The storage medium can be any available medium that can be accessed by a computer. As an example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage device, magnetic disk storage device or other magnetic storage device, or any other medium that can be used to store the desired program code in the form of instructions or data structures and can be accessed by a computer.

[0107] In this document, the term "module" as used herein refers to software, firmware, hardware, and any combination of these elements for performing the associated functions described herein. Additionally, for the purpose of discussion, various modules are described as discrete modules; however, as is apparent to one of ordinary skill in the art, according to embodiments of the present solution, two or more modules may be combined to form a single module that performs the associated functions.

[0108] Additionally, in an embodiment of the present solution, a memory or other storage device and a communication component may be used. It should be understood that, for clarity, the above description has described an embodiment of the present solution with reference to different functional units and processors. However, it is apparent that any suitable functional distribution between different functional units, processing logic elements or domains may be used without departing from the present solution. For example, a function shown as being performed by a separate processing logic element or controller may be performed by the same processing logic element or controller. Therefore, reference to a specific functional unit is merely a reference to a suitable means for providing the described functionality, rather than indicating a strict logical or physical structure or organization.

[0109] Various modifications to the embodiments described in this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the novel features and principles disclosed herein, as set forth in the above claims.

Claims

1. A method comprising: The wireless communication node receives a first radio resource configuration RRC message from the wireless communication device, wherein the first RRC message includes: an indication that a successful handover report SHR is available at the wireless communication device, and an indication of a radio access technology RAT type associated with the SHR; and The wireless communication node receives a second RRC message from the wireless communication device, the second RRC message including the SHR and the first information.

2. The method according to claim 2, wherein: The first information includes at least one of the following: an indication of the RAT type associated with the SHR, or Second information of at least one node triggering the SHR, the second information comprising at least one of the following: The source cell global identifier CGI of the handover associated with the SHR, the target cell global identifier CGI of the handover, the source new generation radio access node NG-RAN node identifier ID or source enhanced NodeB eNB ID of the handover, the source tracking area TA of the handover, the target NG-RAN node ID or target eNB ID of the handover, the target TA of the handover, the triggered CGI of the cell configured with the triggering condition of the SHR that has been met, or the triggered NG-RAN node ID or eNB ID associated with the cell configured with the triggering condition.

3. The method of claim 1 , comprising the wireless communication node determining a first target node to which the SHR is to be sent, in, According to the second information, the first target node is a source node or a target node of a handover associated with the SHR, or a triggered node associated with a cell configured with a triggering condition of the SHR that has been satisfied.

4. The method according to claim 3, comprising the wireless communication node sending an Xn application protocol XnAP message to the first target node, the XnAP message comprising at least one of the following: The SHR in Long Term Evolution LTE format or 5G New Radio NR format; The source cell radio network temporary identifier C-RNTI; or Mobility information.

5. The method according to claim 1, wherein: The SHR is encoded according to a RAT type of a node configured with at least one condition for triggering the SHR.

6. The method according to claim 3, comprising the wireless communication node sending a new generation application protocol NGAP message to a core network, so as to send the SHR to the first target node through the core network, wherein the NGAP message includes at least one of the following: the SHR in LTE format or 5G NR format; The source C-RNTI; or Mobility information.

7. The method according to claim 6, wherein: The core network sends at least one NGAP message to the first target node, where the at least one NGAP message includes at least one of the following: the SHR in LTE format or 5G NR format; the C-RNTI; or The mobility information.

8. The method according to claim 1, 4 or 7, wherein: The wireless communication node or the first target node includes a centralized unit CU, and the CU sends an F1 application protocol F1AP message to a distributed unit DU of the wireless communication node or the first target node, wherein the F1AP message includes at least one of the following: the SHR in LTE format or 5G NR format; the C-RNTI; or The mobility information.

9. The method according to claim 3, comprising: The wireless communication node sends an X2 application protocol X2AP message to the first target node, where the X2AP message includes at least one of the following: the SHR in LTE format or 5G NR format; The source C-RNTI; or Mobility information.

10. The method according to claim 3, comprising: The wireless communication node sends an S1 application protocol S1AP message to a first core network of LTE, so as to send the SHR to the first target node through the first core network and the second core network, wherein the S1AP message includes at least one of the following: the SHR in LTE format or 5G NR format; The source C-RNTI; or Mobility information.

11. The method according to claim 10, wherein: The second core network sends an NGAP message to the first target node, where the NGAP message includes at least one of the following: the SHR in LTE format or 5G NR format; the C-RNTI; or The mobility information.

12. A method comprising: The wireless communication device sends a first radio resource configuration RRC message to the wireless communication node, wherein the first RRC message includes: an indication that a successful handover report SHR is available at the wireless communication device, and an indication of a radio access technology RAT type associated with the SHR; and The wireless communication device sends a second RRC message to the wireless communication node, where the second RRC message includes the SHR and the first information.

13. A non-transitory computer-readable storage medium storing instructions, which, when executed by at least one processor, cause the at least one processor to perform the method according to any one of claims 1 to 12.

14. An apparatus comprising at least one processor, the processor being configured to execute the method according to any one of claims 1 to 12.

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