Release of conditional primary and secondary cell addition / modification configuration

Abstract

In a wireless terminal, a secondary cell group (SCG) configuration is invalidated when a master key changes. The wireless terminal includes a processor circuit and a receiver circuit. The processor circuit is configured to establish a first security context on a first radio connection with a primary access node using a first master key. The receiver circuit is configured to receive a reconfiguration message including one or more conditional secondary cell configurations and at least one counter. Each conditional secondary cell configuration may include an identity of a candidate primary and secondary cell and at least one trigger condition, the candidate primary and secondary cell being used for dual connectivity (DC). The at least one counter and the first master key can be used to derive a second master key, the second master key being used to establish a second security context with one of the candidate primary and secondary cells. The processor circuit is further configured to invalidate the one or more conditional secondary cell configurations when the first master key changes.

Description

Technical Field

[0001] The present technology relates to wireless communications, and in particular to conditional handover in radio access networks. Background Art

[0002] The radio access network typically resides between a wireless device (such as a user equipment (UE), mobile phone, mobile station, or any other device with a wireless terminal) and the core network. Examples of radio access network types include: GRAN, which is the GSM radio access network; GERAN, which includes EDGE packet radio service; UTRAN, which is the UMTS radio access network; E-UTRAN, which includes long term evolution; and g-UTRAN, which is new radio (NR).

[0003] The radio access network may include one or more access nodes, such as base station nodes, that facilitate wireless communications or otherwise provide an interface between wireless terminals and the telecommunications system. Non-limiting examples of base stations may include Node B ("NB"), enhanced Node B ("eNB"), Home eNB ("HeNB"), gNB (for New Radio ["NR"] technology systems), or some other similar terminology, depending on the radio access technology type.

[0004] The 3rd Generation Partnership Project ("3GPP") is a group that develops collaborative agreements, such as 3GPP standards, that aim to establish globally applicable technical specifications and technical reports for wireless communication systems. Various 3GPP documents may describe certain aspects of radio access networks. The overall architecture of fifth-generation systems (e.g., 5G systems, also referred to as "NR" or "New Radio," and "NG" or "Next Generation") is described in [the original text]. Figure 1 As shown in Figure 1 and also described in 3GPP TS 38.300, the 5G NR network consists of the NGRAN (Next Generation Radio Access Network) and the 5GC (5G Core Network). As shown in the figure, the NGRAN consists of gNBs (e.g., 5G base stations) and ng-eNBs (i.e., LTE base stations). Xn interfaces exist between gNBs, between (gNB) and (ng-eNB), and between (ng-eNB) and (ng-eNB). Xn is the network interface between NG-RAN nodes. Xn-U represents the Xn user plane interface, and Xn-C represents the Xn control plane interface. The NG interface exists between the 5GC and the base stations (i.e., gNB and ng-eNB). The gNB node provides NR user plane and control plane protocol terminations to the UE and is connected to the 5GC via the NG interface. The 5G NR (New Radio) gNB is connected to the AMF (Access and Mobility Management Function) and UPF (User Plane Function) in the 5GC (5G Core Network).

[0005] In a typical cellular mobile communication system, a handover (HO) procedure is used to manage the mobility of wireless terminals (e.g., user equipment (UE)). Generally speaking, there are two types of handovers: (1) hard handover and (2) soft handover. In a hard handover (HO), the connection between the wireless terminal and the current (source) base station is temporarily disconnected before a new connection is established between the wireless terminal and the target base station. In contrast, in a soft handover (HO), a new connection is prepared before the connection with the current base station is disconnected.

[0006] 3GPP has finalized the basic functionality of the New Radio (NR) system in Release 15. 3GPP Release 15 only describes basic handover, also known as hard handover. The basic hard handover described in 3GPP Release 15 is primarily based on LTE handover mechanisms, where the network controls UE mobility based on UE measurement reports. In basic hard handover described in 3GPP Release 15, similar to LTE, the source gNB triggers the handover by sending a HO request to the target gNB. After receiving an acknowledgment (ACK) from the target gNB, the source gNB initiates the handover by sending a HO command to the UE, which includes the target cell configuration. The UE then performs initial access to the target cell to establish a connection with it.

[0007] In 3GPP Release 16, several HO improvements are being standardized. Conditional Handover (CHO) is one of these 3GPP Release 16 improvements aimed at improving the reliability and robustness of handovers. In CHO, the gNB of the source cell provides CHO configuration parameters, including candidate target cells and triggering conditions, to a UE in the RRC_CONNECTED state. After receiving the CHO configuration parameters, the UE can perform radio signal measurements from the source cell and the candidate target cells and autonomously initiate handover to one of the candidate cells whose triggering conditions are met.

[0008] Therefore, there is a need for apparatuses, methods, and procedures for effectively and efficiently implementing conditional handover to a secondary cell group (SCG). Summary of the Invention

[0009] In one example, a wireless terminal includes: a processor circuit configured to establish a first security context on a first radio connection with a primary access node using a first access stratum (AS) master key; a receiver circuit configured to receive a reconfiguration message comprising one or more conditional secondary cell group (SCG) configurations and at least one counter, each conditional SCG configuration comprising an identity of a candidate target primary cell (PSCell) of the SCG and at least one trigger condition, the candidate target PSCell being used for dual connectivity (DC), the at least one counter and the first AS master key being used to derive a second AS master key, the second AS master key being used to establish a second security context with a candidate target PSCell included in one of the one or more conditional SCG configurations; and the processor circuit being further configured to store the one or more conditional SCG configurations, wherein: the stored one or more conditional secondary cell configurations are released when the first AS master key changes.

[0010] In one example, a method for a wireless terminal includes: establishing a first security context on a first radio connection with a primary access node using a first access stratum (AS) master key; receiving a reconfiguration message, the reconfiguration message including one or more conditional secondary cell group (SCG) configurations and at least one counter, each conditional SCG configuration including an identity of a candidate target primary cell (PSCell) of the SCG and at least one trigger condition, the candidate target PSCell being used for dual connectivity (DC), the at least one counter and the first AS master key being used to derive a second AS master key, the second AS master key being used to establish a second security context with a candidate target PSCell included in one of the one or more conditional SCG configurations; and storing the one or more conditional SCG configurations, wherein: the stored one or more conditional SCG configurations are released when the first AS master key changes.

[0011] In one example, an access node includes: a processor circuit configured to establish a first security context on a first radio connection with a wireless terminal using a first access stratum (AS) master key; a transmitter circuit configured to transmit a reconfiguration message, the reconfiguration message including one or more conditional secondary cell group (SCG) configurations and at least one counter, each conditional SCG configuration including the identity of a candidate target primary cell (PSCell) of the SCG and at least one trigger condition, the candidate target PSCell being used for dual connectivity (DC), the at least one counter and the first AS master key being used to derive a second AS master key, the second AS master key being used to establish a second security context with a candidate target PSCell included in one of the one or more conditional SCG configurations; wherein: the one or more conditional SCG configurations are released when the first master key changes.

[0012] In one example, a method for an access node includes: establishing a first security context on a first radio connection with a wireless terminal using a first access stratum (AS) master key; transmitting a reconfiguration message, the reconfiguration message including one or more conditional secondary cell group (SCG) configurations and at least one counter, each conditional SCG configuration including an identity of a candidate target primary cell (PSCell) for the SCG and at least one trigger condition, the candidate target PSCell being used for dual connectivity (DC), the at least one counter and the first master key being used to derive a second AS master key, the second AS master key being used to establish a second security context with a candidate target PSCell included in one of the one or more conditional SCG configurations; wherein: the one or more conditional SCG configurations are released when the first AS master key changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] [ Figure 1 ] Figure 1 A diagrammatic view of the overall architecture of the 5G New Radio system.

[0014] [ Figure 2 ] Figure 2 A diagrammatic view showing transition states of a radio resource control (RRC) state machine.

[0015] [ Figure 3 ] Figure 3 A diagrammatic view illustrating signalling and messages for a basic handover procedure / scenario in an exemplary cellular communication system.

[0016] [ Figure 4 ] Figure 4 A diagrammatic view illustrating exemplary parameters of a measurement configuration that may be provided by a source node of a radio access network.

[0017] [ Figure 5 ] Figure 5 is a diagrammatic view showing exemplary information elements of an exemplary MeasurementReport message.

[0018] [ Figure 6 ] Figure 6 is a schematic diagram of an exemplary communication system including a source gNodeB that provides conditional handover configuration information to a wireless terminal that the wireless terminal can use to control generation and / or content of measurement reports.

[0019] [ Figure 7 ] Figure 7 To show Figure 6 A diagrammatic view of the signaling and messages involved in measurement reporting for a conditional handover scenario of an exemplary cellular communication system.

[0020] [ Figure 8 ] Figure 8 To show Figure 6 A diagrammatic view of exemplary general contents of an exemplary conditional handover configuration message of an exemplary embodiment of FIG.

[0021] [ Figure 9 ] Figure 9 To show that Figure 6 A flowchart of exemplary basic representative steps or actions performed by a source node of a system.

[0022] [ Figure 10 ] Figure 10 To show that Figure 6 Flowchart of exemplary basic representative steps or actions performed by a wireless terminal of a system.

[0023] [ Figure 11 ] Figure 11 is a schematic diagram of an exemplary communication system including a source gNodeB that provides a wireless terminal with conditional handover configuration information that allows the wireless terminal to periodically report measurement results of candidate target gNodeBs.

[0024] [ Figure 12 ] Figure 12 To show Figure 11 A diagrammatic view of the signaling and messages involved in measurement reporting for a conditional handover scenario of an exemplary cellular communication system.

[0025] [ Figure 13 ] Figure 13 To show that Figure 11 A flowchart of exemplary basic representative steps or actions performed by a source node of a system.

[0026] [ Figure 14 ] Figure 14 To show that Figure 11 Flowchart of exemplary basic representative steps or actions performed by a wireless terminal of a system.

[0027] [ Figure 15 ] Figure 15 is a schematic diagram of an exemplary communication system including a source gNodeB that provides a wireless terminal with conditional handover configuration information that notifies the wireless terminal of conditions for leaving conditional handover.

[0028] [ Figure 16 ] Figure 16 To show Figure 15 A diagrammatic view of the signaling and messages involved in measurement reporting for a conditional handover scenario of an exemplary cellular communication system.

[0029] [ Figure 17 ] Figure 17 To show that Figure 15 A flowchart of exemplary basic representative steps or actions performed by a source node of a system.

[0030] [ Figure 18 ] Figure 18 To show that Figure 15 Flowchart of exemplary basic representative steps or actions performed by a wireless terminal of a system.

[0031] [ Figure 19 ] Figure 19 is a schematic diagram of an exemplary communication system including a source gNodeB that provides a conditional handover configuration including a security configuration to a wireless terminal.

[0032] [ Figure 20 ] Figure 20 To illustrate the steps performed by the wireless terminal to derive the master key K for the AS security context gNB A diagrammatic view of exemplary basic representative actions.

[0033] [ Figure 21 ] Figure 21 To show Figure 19 A diagrammatic view of exemplary general contents of an exemplary conditional handover configuration message including a security configuration according to an exemplary embodiment of FIG.

[0034] [ Figure 22 ] Figure 22 To show Figure 19 A diagrammatic view of exemplary general contents of a second security configuration information element of an exemplary embodiment of FIG.

[0035] [ Figure 23A ] Figure 23A To show that it can be Figure 19A diagrammatic view of a common second security configuration information element associated with multiple candidate target cells according to an exemplary embodiment.

[0036] [ Figure 23B ] Figure 23B To show that it can be Figure 19 A diagrammatic view of a particular second security configuration information element associated with a unique candidate target cell according to an exemplary embodiment.

[0037] [ Figure 23C ] Figure 23C A diagrammatic view showing a message having a plurality of second security configuration information elements, wherein different second security configuration information elements of the message are Figure 19 The exemplary embodiment of one or more candidate target cells is associated with different groups.

[0038] [ Figure 24 ] Figure 24 To show that Figure 19 Flowchart of exemplary basic representative actions performed by a source gNodeB of exemplary embodiments and modes.

[0039] [ Figure 25 ] Figure 25 To show that Figure 19 Flowchart of exemplary basic representative actions performed by a wireless terminal of an exemplary embodiment and mode.

[0040] [ Figure 26 ] Figure 26 A flow chart illustrating exemplary basic representative actions performed by a wireless terminal that receives a first security context and thereafter, if a conditional handoff is triggered, determines whether to establish a security configuration for a target.

[0041] [ Figure 27 ] Figure 27 A flowchart illustrating exemplary basic representative actions performed by an access node (e.g., a gNB) to establish a first security context, determine a key set to be used for a candidate target cell, and transmit a conditional handover configuration to a wireless terminal after handover coordination.

[0042] [ Figure 28 ] Figure 28 is a schematic diagram of an exemplary communication system including a source gNodeB that provides a conditional handover configuration for a wireless terminal and checks the handover configuration.

[0043] [ Figure 29 ] Figure 29 Different scenarios are shown where the conditional handover configuration needs to be released or can be retained.

[0044] [ Figure 30 ] Figure 30 Different scenarios are shown where the conditional handover configuration needs to be released or can be retained.

[0045] [ Figure 31 ] Figure 31 Different scenarios are shown where the conditional handover configuration needs to be released or can be retained.

[0046] [ Figure 32 ] Figure 32 Different scenarios are shown where the conditional handover configuration needs to be released or can be retained.

[0047] [ Figure 33 ] Figure 33 Different scenarios are shown where the conditional handover configuration needs to be released or can be retained.

[0048] [ Figure 34 ] Figure 34 Different scenarios are shown where the conditional handover configuration needs to be released or can be retained.

[0049] [ Figure 35 ] Figure 35 To show that Figure 28 Flowchart of exemplary basic representative actions performed by a source gNodeB of exemplary embodiments and modes.

[0050] [ Figure 36 ] Figure 36 To show that Figure 28 Flowchart of exemplary basic representative actions performed by a wireless terminal of an exemplary embodiment and mode.

[0051] [ Figure 37 ] Figure 37 is a schematic diagram of an exemplary communication system including a source gNodeB that provides a secondary cell group (SCG) configuration for a wireless terminal.

[0052] [ Figure 38 ] Figure 38 is a diagrammatic view showing a network diagram for dual conductivity including a primary cell group and a secondary cell group.

[0053] [ Figure 39 ] Figure 39 To show that Figure 37 Flowchart of representative general steps or actions performed by a master gNodeB.

[0054] [ Figure 40 ] Figure 40 To show that Figure 37 Flowchart of representative general steps or actions performed by a wireless terminal.

[0055] [ Figure 41 ] Figure 41 A diagram illustrating the actions, steps or messages comprising a procedure for adding or newly configuring a secondary node (ie, adding a new SCG configuration).

[0056] [ Figure 42 ] Figure 42 A diagram illustrating actions, steps or messages comprising a procedure for modifying a current secondary cell group (SCG) configuration within the same secondary node.

[0057] [ Figure 43 ] Figure 43 To show the Figure 37 A diagrammatic view of an exemplary key derivation scheme for a secondary node of an exemplary embodiment and mode of FIG.

[0058] [ Figure 44 ] Figure 44 is a schematic diagram of an exemplary communication system including a source gNodeB that provides conditional secondary cell group (SCG) configuration for a wireless terminal.

[0059] [ Figure 45 ] Figure 45 To show that Figure 44 Flowchart of representative general steps or actions performed by a master gNodeB.

[0060] [ Figure 46 ] Figure 46 To show that Figure 44 Flowchart of representative general steps or actions performed by a wireless terminal.

[0061] [ Figure 47 ] Figure 47 is a schematic diagram of an exemplary communication system including a source gNodeB that provides multiple conditional secondary cell group (SCG) configurations for wireless terminals.

[0062] [ Figure 48 ] Figure 48 To show that Figure 47 Flowchart of representative general steps or actions performed by a master gNodeB.

[0063] [ Figure 49 ] Figure 49 To show that Figure 47 Flowchart of representative general steps or actions performed by a wireless terminal.

[0064] [ Figure 50 ] Figure 50 FIG. 1 is a diagram of an exemplary communication system in which one or more conditional secondary cell configurations are invalidated when a first master key is changed.

[0065] [ Figure 51 ] Figure 51 To show that Figure 50 Flowchart of representative general steps or actions performed by a master gNodeB.

[0066] [ Figure 52 ] Figure 52 To show that Figure 50 Flowchart of representative general steps or actions performed by a wireless terminal.

[0067] [ Figure 53 ] Figure 53 To illustrate diagrammatic views of exemplary elements comprising electronic machinery, which may include a wireless terminal, a radio access node, and a core network node according to exemplary embodiments and modes. DETAILED DESCRIPTION

[0068] The foregoing and other objects, features, and advantages of the technology disclosed herein will be apparent from the following more particular description of preferred embodiments, as illustrated in the accompanying drawings, in which reference numerals refer to like parts throughout the various views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the technology disclosed herein.

[0069] For ease of illustration and not limitation, specific details such as specific architectures, interfaces, technologies, etc. are provided in the following description to provide a thorough understanding of the technology disclosed herein. However, it will be apparent to those skilled in the art that the technology disclosed herein may also be implemented in other embodiments that are different from these specific details. That is, those skilled in the art will be able to conceive of various arrangements that, although not explicitly described or shown herein, still embody the principles of the technology disclosed herein and are included within its spirit and scope. In some cases, detailed descriptions of well-known devices, circuits, and methods are omitted so that the description of the technology disclosed herein is not obscure due to non-essential details. All statements describing the principles, aspects, and embodiments of the technology disclosed herein and their specific examples are intended to cover their structural and functional equivalents. In addition, it is intended that such equivalents include currently known equivalents and equivalents developed in the future, i.e., any element developed to perform the same function, regardless of structure.

[0070] Thus, for example, those skilled in the art will appreciate that the block diagrams herein can represent conceptual views of exemplary circuits or other functional units that embody the principles of the technology. Similarly, it will be appreciated that any flow charts, state transition diagrams, pseudocodes, etc. represent various processes that can be substantially represented in a computer-readable medium and thus executed by a computer or processor, regardless of whether such computer or processor is explicitly shown.

[0071] As used herein, the term "core network" may refer to a device, a group of devices, or a subsystem within a telecommunications network that provides services to users of the telecommunications network. Examples of services provided by the core network include aggregation, authentication, call switching, service invocation, and serving as a gateway to other networks.

[0072] As used herein, the term "wireless terminal" may refer to any electronic device used to transmit voice and / or data via a telecommunications system, such as, but not limited to, a cellular network. Other terms used to refer to a wireless terminal and non-limiting examples of such devices may include user equipment terminal, UE, mobile station, mobile device, access terminal, subscriber station, mobile terminal, remote station, user terminal, terminal, subscriber unit, cellular phone, smart phone, personal digital assistant ("PDA"), laptop computer, tablet computer, netbook, e-reader, wireless modem, etc.

[0073] As used herein, the term "access node," "node," or "base station" may refer to any device or group of devices that facilitates wireless communication or otherwise provides an interface between a wireless terminal and a telecommunications system. In the 3GPP specifications, non-limiting examples of a base station may include Node B ("NB"), enhanced Node B ("eNB"), Home eNB ("HeNB"), gNB (for New Radio ["NR"] technology systems), or some other similar terminology.

[0074] As used herein, the term "telecommunication system" or "communication system" may refer to any network of devices used to transmit information. Non-limiting examples of telecommunication systems are cellular networks or other wireless communication systems.

[0075] As used herein, the term "cellular network" or "cellular radio access network" may refer to a network distributed over cells, each of which is served by at least one fixed-position transceiver, such as a base station. A "cell" may be any communication channel specified by a standardization or regulatory body for International Mobile Telecommunications Advanced ("IMTA Advanced"). All or a portion of a cell may be adopted by 3GPP as a licensed frequency band (e.g., a frequency band) to be used for communications between a base station (such as a Node B) and a UE terminal. A cellular network using a licensed frequency band may include configured cells. A configured cell may include a cell that a UE terminal is aware of and has been authorized by a base station to transmit or receive information. Examples of cellular radio access networks include E-UTRAN and any successor networks thereof (e.g., NUTRAN).

[0076] Any reference to "resources" herein refers to "radio resources" unless it is clear from the context that another meaning is intended. Generally speaking, as used herein, a radio resource ("resource") is a time-frequency unit that can carry information (e.g., signal information or data information) over a radio interface. An example of a radio resource occurs in the context of a "frame" of information that is typically formatted and written by a node, for example. A frame that may have both a downlink portion and an uplink portion is transmitted between a base station and a wireless terminal. Each frame may include multiple subframes, and the subframes may be divided into time slots. The signal transmitted in each time slot is described by a resource grid consisting of resource elements (REs). Each column of the two-dimensional grid represents a symbol (e.g., an OFDM symbol on a downlink (DL) from a node to a wireless terminal; an SC-FDMA symbol in an uplink (UL) frame from a wireless terminal to a node). Each row of the grid represents a subcarrier. A resource element (RE) is the smallest time-frequency unit used for downlink transmission in a subframe. That is, one symbol on one subcarrier in a subframe includes a resource element (RE) uniquely defined by an index pair (k, 1) in the slot (where k and 1 are indices in the frequency and time domains, respectively). In other words, one symbol on one subcarrier is a resource element (RE). Each symbol includes multiple subcarriers in the frequency domain, the specific number of which depends on the channel bandwidth and configuration. The minimum time-frequency resource supported by current standards is a collection of multiple subcarriers and multiple symbols (e.g., multiple resource elements (REs)), and is referred to as a resource block (RB). In the case of a canonical cyclic prefix, a resource block may include, for example, 84 resource elements, i.e., 12 subcarriers and 7 symbols.

[0077] As described herein, both access nodes and wireless terminals may manage corresponding radio resource control (RRC) state machines. The RRC state machine transitions between several RRC states, including RRC_IDLE, RRC_INACTIVE, and RRC_CONNECTED. Figure 2 A state transition diagram depicts the RRC states. From the vantage point of a wireless terminal, such as a user equipment (UE), the RRC states can be simply characterized as follows:

[0078] RRC_IDLE:

[0079] UE-specific DRX (discontinuous reception) can be configured by upper layers;

[0080] UE-controlled mobility based on network configuration;

[0081] UE:

[0082] ○Monitor the paging channel;

[0083] o Perform neighbor cell measurements and cell (re)selection;

[0084] ○Get system information.

[0085] RRC_INACTIVE:

[0086] UE-specific DRX can be configured by upper layers or the RRC layer;

[0087] UE-controlled mobility based on network configuration;

[0088] The UE stores the access stratum (AS) context;

[0089] UE:

[0090] ○Monitor the paging channel;

[0091] o Perform neighbor cell measurements and cell (re)selection;

[0092] ○ Perform RAN-based notification area updates when moving outside of the RAN-based notification area;

[0093] ○Get system information.

[0094] RRC_CONNECTED:

[0095] ·UE stores the AS context.

[0096] • Transferring unicast data to / from UE.

[0097] At lower layers, the UE may be configured with UE-specific DRX;

[0098] Network-controlled mobility, i.e. handover within NR and to / from E-UTRAN;

[0099] UE:

[0100] ○Monitor the paging channel;

[0101] o monitoring a control channel associated with a shared data channel to determine whether data is scheduled for it;

[0102] ○Provide channel quality and feedback information;

[0103] ○Perform neighbor cell measurements and measurement reporting;

[0104] ○Get system information.

[0105] Figure 3The process / scenario of a basic handover in a cellular communication system is illustrated. During the RRC_CONNECTED state, depicted by action 3-0, a wireless terminal, such as a UE, may receive an RRCReconfiguration message from the gNB of the current serving cell (source cell) as action 3-1. The RRCReconfiguration message of action 3-1 may include configuration parameters for (a) radio signal measurement and (b) reporting measurement results (measurement configuration). The RRCReconfiguration message of action 3-1 may be acknowledged with an RRCReconfigurationComplete message, as shown in action 3-2. Thereafter, the UE may begin measurement and, as shown in actions 3-3a, 3-3b, and 3-3i, may transmit measurement results to the gNB of the source cell based on the configuration parameters received in the RRCReconfiguration message of action 3-1. The configuration parameters may include the radio resources used for measurement (frequency, subcarrier spacing, etc.) and conditions for triggering reporting. Upon receiving one of the measurement reports of action 3-3x, the gNB of the source cell may determine, as action 3-4, whether to handover the UE to another cell. For example, when the measurement report indicates that the UE is from a neighboring cell ( Figure 3 When the signal quality of the target cell (in the target cell) is better than the signal quality of the source cell, the gNB of the source cell may initiate a handover to the target cell. As shown in action 3-5, the gNB may then perform a coordination procedure with the gNB of the target cell. After the coordination depicted in action 3-5 is completed, the gNB may send an RRCReconfiguration message to the UE, as shown in action 3-6. The RRCReconfiguration message of action 3-6 may include a handover command to the target cell. Upon receiving the RRCReconfiguration message of action 3-6 with the handover command, the UE may initiate initial access to the target cell by sending a random access preamble, as shown in action 3-7. In response to sending the random access preamble as shown in action 3-7, the UE should receive a random access response message as shown in action 3-8. The UE then sends an RRCReconfigurationComplete message to the gNB of the target cell to complete the handover procedure, as shown in action 3-9.

[0106] In one configuration, the measurement configuration that may be implemented by the parameters of the RRCReconfiguration message of action 3-1 may include Figure 4 Parameters shown as "measurement object", "report configuration", "measurement identity", "quantity configuration" and "measurement gap" in FIG, each of which is described below.

[0107] 1. Measurement objects: A list of objects on which the UE should perform measurements.

[0108] For intra-frequency and inter-frequency measurements, a measurement object (MO) indicates the frequency / time location and subcarrier spacing of the reference signal to be measured. Associated with this measurement object, the network can configure a list of cell-specific offsets: a list of "blacklist" cells and a list of "whitelist" cells. Blacklisted cells are not eligible for event evaluation or measurement reporting. Whitelisted cells are eligible for event evaluation or measurement reporting.

[0109] -The measObjectId corresponding to the MO of each serving cell is indicated by servingCellMO within the serving cell configuration.

[0110] For inter-RAT E-UTRA measurements, the measurement target is a single E-UTRA carrier frequency. Associated with this E-UTRA carrier frequency, the network can configure a list of cell-specific offsets, namely a list of "blacklist" cells and a list of "whitelist" cells. Blacklisted cells are not eligible for event evaluation or measurement reporting. Whitelisted cells are eligible for event evaluation or measurement reporting.

[0111] 2. Report configuration: A list of report configurations, where each measurement object can have one or more report configurations. Each report configuration may include the following:

[0112] -Reporting criteria: The criteria that triggers the UE to send measurement reports. This can be a periodic or single event description.

[0113] - Reference Signal (RS) Type: RS (synchronization signal SS / physical broadcast channel PBCH block or channel state information reference signal CSI-RS) used by the UE for beam and cell measurement results.

[0114] - Reporting format: The number of cells and beams included by the UE in the measurement report, e.g., received signal power, RSRP, and other associated information, such as the maximum number of cells to be reported and the maximum number of beams per cell.

[0115] 3. Measurement Identifiers: A list of measurement identifiers, each of which links a measurement object to a reporting configuration. By configuring multiple measurement identifiers, more than one measurement object can be linked to the same reporting configuration, and more than one reporting configuration can be linked to the same measurement object. The measurement identifier is also included in the measurement report that triggered the report and serves as a reference to the network.

[0116] 4. Quantity Configuration: The quantity configuration defines the measurement filter configuration used for all event evaluations and related reporting, as well as periodic reporting of that measurement. For NR measurements, the network can configure up to two quantity configurations, where the reference in the NR measurement object is the configuration to be used. Within each configuration, different filter coefficients can be configured for different measurement quantities, for different RS types, and for measurements per cell and per beam.

[0117] 5. Measurement gap: A period during which the UE can perform measurements.

[0118] A UE in the RRC_CONNECTED state may maintain a list of measurement objects, a list of reporting configurations, and a list of measurement identities. The list of measurement objects may include New Radio (NR) measurement objects and inter-RAT objects. Similarly, the list of reporting configurations may include NR and inter-RAT reporting configurations. Any measurement object may be linked to any reporting configuration of the same RAT type. Some reporting configurations may not be linked to a measurement object. Similarly, some measurement objects may not be linked to a reporting configuration.

[0119] The measurement process distinguishes three types of cells: serving cells, listed cells, and detected cells. Listed cells are cells listed in the measurement object. Detected cells are cells not listed in the measurement object but detected by the UE on the synchronization signal block, SSB, frequency, and subcarrier spacing indicated by the measurement object.

[0120] For measurement objects, the UE measures and reports on the serving cell, listed cells and / or detected cells. For inter-RAT measurement objects in E-UTRA, the UE measures and reports on listed cells and detected cells.

[0121] Listing 1 shows an exemplary implementation of measurement configuration according to 3GPP TS 38.331 v15.5.1.

[0122] List 1

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130] Listing 2 shows an exemplary process of measurement report triggering.

[0131] List 2

[0132]

[0133]

[0134]

[0135] In the measurement reporting process described above, the UE may transmit a MeasurementReport message to the gNB of the serving cell (source cell). The MeasurementReport message may include the measId that triggers the measurement report, the measurement result of the serving cell, the best neighboring cell, and / or the cell that triggered the reporting event, such as Figure 5 As shown by way of example in . It should be noted that for event-driven (eventTriggered) reporting, there are two conditions: entry conditions and exit conditions. The entry condition is met when a specific event occurs, and the exit condition is met when the condition for the specific event no longer exists. In addition, the parameter of hysteresis may be involved in determining the entry / exit conditions to avoid the ping-pong effect. For example, for event A1, the entry condition is met when the signal strength of the serving cell is better than a1 threshold + hysteresis, and the exit condition is met when the signal strength is worse than a1 threshold - hysteresis. When the entry condition is met, the UE may generate and send a MeasurementReport. On the other hand, when the exit condition is met, whether to send a MeasurementReport may depend on the parameter reportOnLeave associated with the relevant event.

[0136] Listing 3 shows an exemplary implementation of MeasurementReport.

[0137] List 3

[0138]

[0139]

[0140] Five basic exemplary embodiments and modes of conditional switching configurations and techniques according to the technology disclosed herein are described below in a general, non-limiting manner.

[0141] 1: Conditional switch configuration and reporting

[0142] Figure 6An exemplary communication system 20 is shown in which a source radio access node 22 communicates with a wireless terminal 26 over an air or radio interface 24 (e.g., a Uu interface). The source radio access node may also communicate with a target radio access node 28 over a suitable interface, such as the radio interface 24 in the case of a backhaul configuration, or Figure 1 X in the manner shown n interface.

[0143] As described above, the radio access node 22 may be any suitable node for communicating with the wireless terminal 26, such as a base station node, a gNodeB ("gNB"), or an eNodeB ("eNB"). For simplicity, the source radio access node 22 may be referred to herein as simply the source node 22, or the source gNodeB 22, or the source gNB 22. Similarly, the target radio access node 28 may be referred to herein as simply the target node 28, or the target gNodeB 28, or the target gNB 28.

[0144] The source gNodeB 22 includes node processor circuitry ("node processor 30") and node transceiver circuitry 32. The node transceiver circuitry 32 generally includes node transmitter circuitry 34 and node receiver circuitry 36, also referred to as a node transmitter and a node receiver, respectively. Additionally, the source gNodeB 22 may include inter-node interface circuitry 38 for communicating with the target gNodeB 28. Although not shown as such, it should be understood that the target gNodeB 28 may similarly have its own node processor 30, node transceiver circuitry 32, and inter-node interface circuitry 38.

[0145] The wireless terminal 26 includes a terminal processor 40 and a terminal transceiver circuit 42. The terminal transceiver circuit 42 generally includes a terminal transmitter circuit 44 and a terminal receiver circuit 46, also referred to as a terminal transmitter 44 and a terminal receiver 46, respectively. The wireless terminal 26 also includes a user interface 48. The terminal user interface 48 can be used for user input and output operations and can include, for example, a screen such as a touch screen that can display information to the user and receive information input by the user. For example, the user interface 48 can also include other types of devices, such as a speaker, a microphone, or a tactile feedback device.

[0146] For both the radio access node 22 and the radio interface 24, the respective transceiver circuitry 22 includes an antenna. The respective transmitter circuitry 36 and 46 may include, for example, amplifiers, modulation circuitry, and other conventional transmission equipment. The respective receiver circuitry 34 and 44 may include, for example, amplifiers, demodulation circuitry, and other conventional receiver equipment.

[0147] In general operation, the source gNodeB 22 and the wireless terminal 26 communicate with each other over the radio interface 24 using a predefined information configuration. As a non-limiting example, the gNodeB 22 and the wireless terminal 26 may communicate over the radio interface 24 using information "frames" that may be configured to include various channels. For example, a frame, which may have both a downlink portion and an uplink portion, may include multiple subframes, each of which is in turn divided into multiple time slots. The frame can be conceptualized as a resource grid (a two-dimensional grid) composed of resource elements (REs). Each column of the two-dimensional grid represents a symbol (e.g., an OFDM symbol on a downlink (DL) frame from a node to a wireless terminal; an SC-FDMA symbol in an uplink (UL) frame from a wireless terminal to a node). Each row of the grid represents a subcarrier. The frame and subframe structures are merely examples of formatting techniques for information to be transmitted over the radio interface or air interface. It should be understood that "frame" and "subframe" may be used interchangeably or may include or be implemented by other information formatting units and, therefore, may be accompanied by other terminology (such as block).

[0148] In order to satisfy the information transmission between gNodeB 22 and wireless terminal 26 through radio interface 24, Figure 6 The node processor 30 and terminal processor 40 of the wireless terminal 26 are shown as including corresponding information processing programs. For the exemplary embodiment of transmitting information via frames, the information processing program of the gNodeB 22 is shown as a node frame / signal scheduler / processor 50, while the information processing program of the wireless terminal 26 is shown as a terminal frame / signal processor 52.

[0149] The node processor 30 of the source gNodeB 22 also includes a message generator 54, an RRC state machine 56, and a handover controller 60. For example, the RRC state machine 56 may be configured to receive a message from a source gNodeB 22. Figure 2 The handover controller 60 may operate in an understood manner and may interact with the message generator 54 for generating RRC messages, such as RRCReconfiguration messages. The handover controller 60 may include a measurement analyzer 62, a conditional handover (CHO) determination unit 64, and a conditional handover configuration information generator 66.

[0150] The terminal processor 40 of the wireless terminal 26 further includes a message processor 70, a switching unit 72, and a measurement controller 80. The measurement controller 80 in turn further includes a measurement initiation unit 82; a measurement result unit 84; and a measurement report control unit 86.

[0151] Figure 7 An exemplary scenario is shown, where Figure 6 The communication system can perform conditional switching. Figure 7 Some actions similar to Figure 3Those actions of the wireless terminal 26 have similar suffix action numbers, such as action 7-0, which, like action 2-0, shows that the UE is in the RRC_CONNECTED state. Similarly, like action 3-1, action 7-1 shows that the wireless terminal 26 can be configured with a measurement configuration by the gNB 22 of the serving cell (source cell). The measurement configuration of action 7-1 can be similar to the measurement configuration of Listing 1. Based on the measurement configuration received in action 7-1, the wireless terminal 26 can send a measurement report 7-3. The timing of the measurements performed by the wireless terminal 26 can be managed by the measurement initiation unit 82, the measurement results are analyzed by the measurement result unit 84, and the measurement report can be generated by 86. The measurement report can be similar to the exemplary implementation shown in Listing 3. Reference can be made to Listing 1 to understand the exemplary logic for the decision to trigger action 7-4, for example, the process for measurement report triggering.

[0152] Figure 7 Also shown, in this particular scenario, as action 7-4, gNB 22 makes a decision to send a conditional handover (CHO) configuration to wireless terminal 26. The decision in action 7-4, which may be made by conditional handover (CHO) determination unit 64, is triggered by the measurement results of the target cell evaluated by measurement analyzer 62 (i.e., measurement report 7-3). Action 7-5 illustrates the handover coordination process performed following the decision in action 7-4. The handover coordination process of action 7-5 is performed to prepare both source gNodeB 22 and target gNodeB 28 for the possibility of handover. Communications involved in the handover coordination process of action 7-5 may be transmitted via inter-node interface 34.

[0153] In one exemplary embodiment, after the handover decision of action 7-4 and the handover coordination procedure of action 7-5, as shown in action 7-6, a message may be sent to the wireless terminal 26 to carry the conditional handover CHO configuration information. The conditional handover configuration information of the message of action 7-6 may be generated by the conditional handover configuration information generator 66. In one exemplary embodiment, the message of action 7-6 may be an RRCReconfiguration message. In another exemplary embodiment (not shown), another suitable message (e.g., RRCCHOConfiguration) may be used to send the conditional handover configuration information. Upon successful receipt of the message of action 7-6, i.e., a message including the conditional handover configuration information and sent to the wireless terminal 26, a response or confirmation message is returned to the source gNodeB 22, as shown in action 7-6'.

[0154] In an exemplary implementation, the message used for act 7-6 (e.g., the message including the CHO configuration information) may include the following parameters:

[0155] Identification of candidate target cells

[0156] Events that trigger the execution of CHO

[0157] RACH configuration of candidate target cells

[0158] UL / DL configuration of candidate target cells

[0159] • New UE identity (eg RNTI) to be used for the candidate target cell.

[0160] Figure 8 The various general information elements or information types that may be included in the conditional handover configuration message of action 7-6 are generally shown, including but not limited to: reference signal type (e.g., SSB or CSI-RS); identifier of the candidate target node; handover condition; measurement instruction; periodicity value of periodic reporting and departure condition. The last three information elements above may be optional and may be discussed in conjunction with other exemplary embodiments and modes.

[0161] Listing 4 shows an information element CHOConfig, which is an exemplary implementation of an information element (IE) to be included in the message of action 7-6 for CHO configuration. In this exemplary implementation, the conditions for triggering the measurement report (EventTriggerConfigCHO) can be configured separately from the conditions included in measConfig (EventTriggerConfig).

[0162] List 4

[0163]

[0164]

[0165]

[0166] exist Figure 7After receiving the CHO configuration in the message of action 7-6, as in previous practice, the wireless terminal 26 may continue the measurement process based on the previously received measurement configuration (e.g., the measurement configuration received in action 7-1 before the handover decision of action 7-4). The earlier measurement configuration (e.g., pre-conditional measurement configuration information) may include a measurement object that includes measurement parameters covering the candidate target cells. In addition, the measurement object of the pre-conditional measurement configuration information may also include a candidate current cell in the whitelist cell. In such a case, the measurement object may trigger a measurement report based on the associated (linked) reporting configuration. However, the serving cell (e.g., the source gNodeB 22) has negotiated with each of the candidate target cells and allows the wireless terminal 26 to autonomously perform a handover to one of the candidate target cells as long as the CHO configuration remains valid. Therefore, once the CHO configuration is provided in the message of action 7-5, sending a measurement report about one of the candidate target cells may be wasteful.

[0167] In view of the above, as one of its features and advantages, when the measurement result of the signal from the candidate target cell meets the reporting condition specified in the corresponding reporting configuration, Figure 6 The wireless terminal 26 may suppress measurement reports for candidate target cells included in the CHO configuration. In other words, the wireless terminal 26 may transmit measurement reports when the measurement results available in the UE include results from cells other than cells configured as candidate target cells. Therefore, the measurement report control unit 86 of the wireless terminal 26, labeled as the measurement report control unit 86, may suppress reporting of measurements for candidate target gNodeBs.

[0168] To reflect the foregoing, Figure 7 The wireless terminal 26 is shown as action 7-3' sending a measurement report based on the conditional handover configuration. For example, assume that the one measurement object is linked to an event-triggered reporting configuration. If the measurement on the measurement object results in finding a cell that meets the triggering condition in the reporting configuration, then if the identity (e.g., physical cell ID) of the found cell is used for any of the candidate target cells in the CHO configuration, then Figure 6 The wireless terminal 26 may send a measurement report if the measurement results for cells other than the candidate target cell are available. Otherwise, the UE may determine not to send a measurement report. If measurement results for cells other than the candidate target cell are available, the wireless terminal 26 may be allowed to include the results from the candidate target cell and the results from the cells other than the candidate target cell in the measurement report.

[0169] Action 7-4' shows that the wireless terminal 26 can determine that the conditional handover condition of the conditional handover configuration information is satisfied and that a handover to the candidate target gNodeB 28 should occur. The determination of action 7-4' can be performed by the handover unit 72 of the wireless terminal 26. Thereafter, the wireless terminal 26 can seek access to the target gNodeB 28 by participating in a random access procedure, as shown in actions 7-7 and 7-8. Action 7-7 includes the wireless terminal 26 sending a random access preamble to the target gNodeB 28. Upon successfully receiving and identifying the target gNodeB 28 of the random access preamble of action 7-7, the wireless terminal 26 should receive a random access response message, as shown in action 7-8. The wireless terminal 26 then sends an RRCReconfigurationComplete message to the target gNodeB 28 to complete the handover procedure, as shown in action 7-9.

[0170] therefore, Figure 6 The source gNodeB 22 provides the wireless terminal 26 with conditional handover configuration information that the wireless terminal 26 can use to control the generation and / or content of measurement reports. Figure 9 It is shown in Figure 6 Example representative basic actions performed by the source gNodeB 22 of . Action 9-1 includes receiving a measurement report from the wireless terminal. The measurement report of action 9-1 may be a report message such as Figure 7 Action 9-2 includes making a determination based on the measurement report for reconfiguring the wireless terminal. The determination of action 9-2 may be made by a conditional handover (CHO) determination unit 64 of the source gNodeB 22 and may also be made by a Figure 7 Action 9-3 includes transmitting a configuration message to the wireless terminal to configure the conditional handover, the configuration message being configured to be used by the wireless terminal to make a decision regarding transmitting the wireless terminal measurement report to the source gNodeB 22.

[0171] Figure 10 It is shown in Figure 6 Example representative basic actions performed by wireless terminal 26 of the embodiment of the present invention. Action 10-1 includes receiving a configuration message from a wireless access node to configure conditional handover. The conditional handover configuration message of action 10-1 may be the message described in action 7-5 above. Action 10-2 includes wireless terminal 26 performing measurements. The measurements may be initiated by measurement initiation unit 82 of wireless terminal 26. Action 10-3 includes wireless terminal 26 deciding to send a measurement report including measurement results based on the configuration message of action 10-2. Action 10-4 includes transmitting the measurement report to source gNodeB 22.

[0172] List 5 is an exemplary process of measurement reporting triggered based on List 2, which supports Figure 6and Figure 7 Revisions of implementation plans and patterns are marked in bold text.

[0173] List 5

[0174]

[0175]

[0176]

[0177] 2: Measurement report after conditional switching configuration

[0178] exist Figure 11 In exemplary embodiments and modes of the present invention, the wireless terminal 26 may be allowed to periodically transmit measurement reports for the candidate target cells for configuration. One reason for allowing the wireless terminal 26 to periodically transmit measurement reports is that the source cell, i.e., the serving cell of the source gNodeB 22, may use the measurement reports to determine whether to release the CHO configuration. Since each of the candidate target cells (such as the target gNodeB 28) reserves radio resources for potential CHO, the radio access network may not want to maintain the reserved resources forever. Therefore, the radio access network may force the wireless terminal 26 to continue reporting measurement results for the candidate target cells.

[0179] Figure 11 The source gNodeB 22, wireless terminal 26 and node processor 30 of the communication system 20 are similar to Figure 6 those of the present invention, wherein similar elements and functions have similar reference numerals. Figure 11 As shown, the source gNodeB 22 includes node processor circuitry ("node processor 30") and node transceiver circuitry 32, wherein the node transceiver circuitry 32 includes a node transmitter 34 and a node receiver 36. The node processor 30 includes a node frame / signal scheduler / handler 50, a message generator 54, an RRC state machine 56, and a handover controller 60, wherein the handover controller 60 in turn includes a measurement analyzer 62, a conditional handover (CHO) determination unit 64, and a conditional handover configuration information generator 66 (11). Figure 6 The exemplary embodiment of Figure 11 The difference between the exemplary embodiment and mode of the present invention is that the conditional handover configuration information generator 66 (11) includes a conditional handover instruction in the conditional handover configuration information, which conditional handover instruction does not suppress the reporting of measurements for the candidate target gNodeB, but allows periodic reporting of measurements for the candidate target gNodeB. The instruction of the conditional handover configuration information that allows periodic reporting of measurement results for the candidate target gNodeB may be included in a "measurement instruction" information element, such as, for example, Figure 8In addition, the periodicity value of the allowed reporting of the measurement results for the candidate target gNodeB may be included in the "periodicity value" information element, for example, such as Figure 8 As shown in the fifth information element of the conditional switching configuration message.

[0180] As in Figure 6 In the exemplary embodiments and modes of Figure 11 The wireless terminal 26 of the exemplary embodiment and mode includes a terminal processor 40 and a terminal transceiver circuit 42, wherein the terminal transceiver circuit 42 in turn includes a terminal transmitter 44 and a terminal receiver 46. The terminal processor 40 includes a terminal frame / signal processing program 52, a message processor 70, a switching unit 72 and a measurement controller 80, wherein the measurement controller 80 in turn includes a measurement initiation unit 82, a measurement result unit 84 and a measurement report control unit 86. Figure 11 In the exemplary embodiment and mode of the invention, the wireless terminal 26 is allowed to periodically transmit measurement results for candidate target gNodeBs, so that Figure 11 The measurement reporting control unit 86 is marked for periodic candidate reporting.

[0181] Figure 12 Shown Figure 11 Example scenario of exemplary embodiments and modes of the invention, wherein after receiving a CHO configuration, the wireless terminal 26 may periodically transmit measurement reports including measurement results of some or all of the candidate target cells. Figure 7 Action Figure 12 The actions have similar suffixes, for example, Figure 12 Action 12-0 is similar to Figure 7 Action 7-0, Figure 12 Action 12-1 is similar to Figure 7 Action 7-1, and so on. Figure 11 and Figure 12 The difference between the exemplary embodiments and modes is that, after the conditional handover coordination of action 12-5, periodic reporting of measurement results for candidate target gNodeBs is allowed. For example, Figure 12 It is shown that the reporting of the measurement results for the candidate target gNodeB does not occur in the first two measurement report messages 12-3'-11(1) and 12-3'-11(2), but occurs in the third measurement report message 12-3'-11(3).

[0182] exist Figure 12In the exemplary case shown, as a result of the third measurement report message 12-3'-11(3), it may occur that, as an action 12-10, the network (e.g., source gNodeB 22) determines that the conditional handover configuration resulting from the conditional handover decision of action 12-4 should be released. For example, such a determination may be made by the conditional handover (CHO) determination unit 64. Following the conditional handover release decision of action 12-10, as an action 12-11, the source gNodeB 22 may participate in the handover release operation of the target gNodeB 28, as reflected in action 12-11. In other words, as an action 12-10, the source cell 22 may decide to release the CHO configuration and, based on such decision, as an action 12-11, negotiate with the candidate target cell (such as the target gNodeB 28) to release the retained resources. Thereafter, as an action 12-12, the source gNodeB 22 may send a conditional handover deconfiguration message to the wireless terminal 26. Upon successful receipt of the Conditional Handover Deconfiguration message, as action 12-13, the wireless terminal 26 replies to the source gNodeB 22 with an RRCReconfigurationComplete message.

[0183] therefore, Figure 11 The source gNodeB 22 allows the wireless terminal 26 to periodically report the measurement results of the candidate target gNodeBs. Figure 13 It is shown in Figure 11 Example representative basic actions performed by the source gNodeB 22 of the wireless terminal. Action 13-1 includes receiving a measurement report from the wireless terminal. Action 13-2 includes making a determination for reconfiguring the wireless terminal based on the measurement report. The determination of action 13-2 may be made by the conditional handover (CHO) determination unit 64 of the source gNodeB 22 and may also be made by the conditional handover (CHO) determination unit 64 of the source gNodeB 22. Figure 12 Action 12-4 is reflected in Action 13-3 including transmitting a configuration message to the wireless terminal to configure the conditional handover, the configuration message being configured to allow periodic reporting of measurement results for the candidate target gNodeB.

[0184] Figure 14 It is shown in Figure 11 Example representative basic actions performed by wireless terminal 26 of FIG. Action 14-1 includes receiving a configuration message from a wireless access node to configure conditional handover. The conditional handover configuration message of action 14-1 may be the message described in action 12-6 above. Action 14-2 includes wireless terminal 26 performing measurements. The measurements may be initiated by measurement initiation unit 82 of wireless terminal 26. Action 14-3 includes wireless terminal 26 deciding to send a measurement report including measurement results based on the configuration message of action 14-2 and the allowed periodicity. Action 14-4 includes transmitting the measurement report to source gNodeB 22.

[0185] In one exemplary implementation, the CHO configuration may indicate whether the wireless terminal 26 needs to transmit measurement reports for some or all of the candidate target cells, and the periodicity of the reports. Listing 6 shows an exemplary format of the CHO configuration based on Listing 4, where the optional field reportPeriodicity configured separately from the report configuration indicates the periodicity of the reports for the relevant target cells. The presence of this optional field may indicate that the UE is forced to transmit measurement reports periodically, while the absence of this field may indicate that the UE should suppress measurement reports, as disclosed in the first exemplary embodiment and mode. The reportPeriodicity field may correspond to Figure 8 The period value information element shown.

[0186] List 6

[0187]

[0188]

[0189]

[0190] Listing 7 is an exemplary process for measurement reporting triggered based on Listing 2, where the revisions supporting this embodiment are marked in bold text.

[0191] List 7

[0192]

[0193]

[0194]

[0195] In another exemplary implementation, the indication in the CHO configuration indicating whether the wireless terminal 26 is required to transmit measurement reports for some or all of the candidate target cells may be a Boolean type field (or a presence / absence type field) that is not associated with a specified periodicity. In this case, after receiving the CHO configuration, if the Boolean type field is set to true (or false) (or the presence / absence type field), the wireless terminal may send measurement reports according to the report configuration in the preconditional measurement configuration (even for the candidate target cells); otherwise, according to the previous embodiment, the wireless terminal may suppress measurement reports for the candidate target cells.

[0196] 3: Reserved conditions for conditional switching configuration

[0197] exist Figure 15In exemplary embodiments and modes of the present invention, the source gNodeB 22 may provide validity information, or conversely, invalidity information, to the wireless terminal 26, which informs the wireless terminal 26 of the validity or currency of the conditional handover configuration information received by the wireless terminal 26 from the source gNodeB 22. One reason for providing such validity (invalidity) information to the wireless terminal 26 is to preclude the continued pendency of aged conditional handover configuration information and / or to force the wireless terminal 26 to report measurement results of a candidate target gNodeB upon the occurrence of one or more departure conditions.

[0198] Figure 15 The source gNodeB 22, wireless terminal 26 and node processor 30 of the communication system 20 are similar to Figure 6 and Figure 11 those of the present invention, wherein similar elements and functions have similar reference numerals. Figure 15 As shown, the source gNodeB 22 includes a node processor circuit ("node processor 30") and a node transceiver circuit 32, wherein the node transceiver circuit 32 includes a node transmitter 34 and a node receiver 36. The node processor 30 includes a node frame / signal scheduler / handler 50, a message generator 54, an RRC state machine 56, and a handover controller 60, wherein the handover controller 60 in turn includes a measurement analyzer 62, a conditional handover (CHO) determination unit 64, and a conditional handover configuration information generator 66 (15). The previous exemplary embodiment is similar to Figure 15 The difference between the exemplary embodiment and the mode is that the conditional handover configuration information generator 66 (15) includes in the conditional handover configuration information: validity (invalidity) information, also called "leaving condition", which the wireless terminal 26 can use to evaluate how long the conditional handover condition is in effect or when to exit the conditional handover condition. As a non-limiting example, in Figure 8 The leaving condition is provided in the information element "leaving condition" shown last in the conditional handover configuration message.

[0199] As in the previous exemplary embodiments and modes, Figure 15 The wireless terminal 26 of the exemplary embodiment and mode includes a terminal processor 40 and a terminal transceiver circuit 42, wherein the terminal transceiver circuit 42 in turn includes a terminal transmitter 44 and a terminal receiver 46. The terminal processor 40 includes a terminal frame / signal processing program 52, a message processor 70, a switching unit 72 and a measurement controller 80, wherein the measurement controller 80 in turn includes a measurement initiation unit 82, a measurement result unit 84 and a measurement report control unit 86. Figure 15 In the exemplary embodiment and mode of the present invention, the wireless terminal 26 is provided with information specifying the validity (invalidity) or departure condition for the conditional handover. Figure 15The measurement reporting control unit 86 (15) is used to use the validity (invalidity) information and / or the departure condition to determine whether to report the measurement results for the candidate target gNodeB.

[0200] Figure 15 The exemplary embodiment discloses the validity of the CHO configuration that the wireless terminal 26 has previously received and associated with the report. In one exemplary implementation, the validity of the CHO configuration may be maintained until the wireless terminal 26 actually performs the handover. In another exemplary implementation, the validity may terminate when the source cell explicitly deconfigures the CHO configuration by sending a message to the UE (e.g., Figure 11 In yet another exemplary embodiment, validity may be managed by at least one timer. In this timer implementation, the wireless terminal 26 may release the CHO configuration upon expiration of the timer, and the radio network (source / candidate target cell) may release the reserved radio resources upon expiration.

[0201] exist Figure 15 In an exemplary embodiment of the present invention, the deconfiguration of the CHO configuration may be based on one or more leaving conditions. These leaving conditions may specify an event in which the UE leaves the CHO configuration.

[0202] Figure 16 Shows that the Figure 15 An exemplary scenario of execution of the system 20. Figure 16 In an exemplary embodiment shown, the UE wireless terminal 26 may use an EventTriggeringConfig configured with a MeasConfig. Thus, the UE may continue the measurement process based on the information element measId in the MeasConfig. For each measId, if the UE detects that one of the candidate target cells satisfies the leaving condition / event specified in the corresponding reportConfig (e.g., measurement result < threshold - hysteresis), the wireless terminal 26 may send a measurement report including the measurement result of the candidate target cell based on the flag reportOnLeave associated with the condition / event. The source cell may release the handover coordination with the candidate target cell and may also send a message for CHO deconfiguration. This scenario Figure 16 Shown in.

[0203] Similar to Figure 7 and Figure 12 Action Figure 16 The actions have similar suffixes, for example, Figure 16 Action 16-0 is similar to Figure 7 Action 7-0, Figure 16 Action 16-1 is similar to Figure 7Action 7-1, and so on. Figure 16 The exemplary embodiment and mode of the present invention differs from the previous exemplary embodiment and mode in that, after the conditional handover coordination of action 16-5, the wireless terminal 26 continues to check whether the invalidity or leaving condition specified in the conditional handover configuration information of message 16-5 is satisfied. If the invalidity or leaving condition specified in the conditional handover configuration information of message 16-5 is not satisfied, the measurement report control unit 86 of the wireless terminal 26 continues to perform the operation similar to Figure 6 and Figure 7 In other words, the measurement report of the measurement result of the candidate target eNode can be transmitted. Figure 6 Action 7-3' of the measurement report, these measurement reports suppress the reporting of measurement results for the candidate target eNode. However, in Figure 16 In the exemplary scenario of , as action 16-4', wireless terminal 26 detects that the invalidity or departure condition specified in the conditional handover configuration information is satisfied. Upon determining in action 16-4 that the current conditions and / or events satisfy the invalidity or departure condition specified in the conditional handover configuration information, wireless terminal 26 then sends a measurement report including the candidate target cell, as reflected in action 16-3'-16. Based on the unsuppressed measurement report or other information received in action 16-3'-16, source gNodeB 22 makes a decision to release the conditional handover as action 16-14. Accordingly, a conditional handover release procedure is performed between source gNodeB 22 and target gNodeB 28, as shown in action 16-15. Thereafter, as action 16-16, source gNodeB 22 may send a conditional handover release message to wireless terminal 26. Upon successful receipt of the conditional handover release message, wireless terminal 26 replies to source gNodeB 22 with an RRCReconfigurationComplete message as action 16-17.

[0204] therefore, Figure 15 The source gNodeB 22 provides certain validity (invalidity) information or departure condition information to the wireless terminal 26 to tell the wireless terminal 26 how long it should suppress measurement result reports for the candidate target gNodeB if report suppression is configured as described in the previous embodiment. Figure 17 It is shown in Figure 15 Example representative basic actions performed by the source gNodeB 22 of the wireless terminal. Action 17-1 includes receiving a measurement report from the wireless terminal. Action 17-2 includes making a determination for reconfiguring the wireless terminal based on the measurement report. The determination of action 17-2 may be made by the conditional handover (CHO) determination unit 64 of the source gNodeB 22 and may also be made by the conditional handover (CHO) determination unit 64 of the source gNodeB 22. Figure 16Action 17-3 includes transmitting a configuration message to the wireless terminal to configure the conditional handover, the configuration message being configured to provide validity (invalidity) or leaving condition information for the conditional handover.

[0205] Figure 18 It is shown in Figure 15 Example representative basic actions performed by the wireless terminal 26 of the wireless access node. Action 18-1 includes receiving a configuration message from the wireless access node to configure conditional handover. The conditional handover configuration message of action 18-1 can be the message of action 16-6 described above. Action 18-2 includes the wireless terminal 26 performing measurements. The measurements can be initiated by the measurement initiation unit 82 of the wireless terminal 26. Action 18-3 includes the wireless terminal 26 making a decision whether to send a measurement report including measurement results for the candidate target gNodeB based on the configuration message of action 14-2 and the validity (invalidity) and / or departure condition information. Action 18-4 includes transmitting the measurement report to the source gNodeB 22.

[0206] In another exemplary implementation, the CHO configuration may include one or more leaving conditions separate from the conditions configured in MeasConfig. For example, the CHO configuration may include a leaving offset for each condition / event, as shown in Listing 8. The wireless terminal 26 may consider the leaving condition to be met when the measurement result of the relevant candidate target cell is lower than ax_Threshold-ax_LeavingOffset, where ax is one of A1, A2, A3, A4, A5, and A6 or any other event (unspecified). Similar to the previous implementation, each condition may be associated with reportOnLeave, thereby instructing the UE whether to transmit a measurement report when the leaving condition is met.

[0207] List 8

[0208]

[0209]

[0210]

[0211] 4: Security configuration for conditional switching configuration

[0212] Typical wireless systems may need to protect user / signaling data from security attacks by applying encryption and integrity protection. To this end, a security context may be established between the terminal and the network entity. Generally, a security context is a security relationship between two or more entities using one or more keys. In LTE / 5G systems, the UE establishes an access stratum (AS) security context with the eNB and / or gNB. The AS security context may be set up in conjunction with a non-access stratum (NAS) security context (established with the Mobility Management Entity (MME) for LTE or the Access and Mobility Management Function (AMF) for 5G). The security context may include one or more security keys derived from some shared secrets stored in the UE and the network entity. The AS security context may first be established immediately after the RRC connection is established (i.e., the initial AS security context), while the NAS security context may first be established during the registration process.

[0213] Figure 19 An exemplary communication system 20 is shown in which security context may be employed in conjunction with handoffs. Figure 19 A system 20 including a source gNodeB 22 , a wireless terminal 26 , and a candidate target node 28 is shown. Figure 19 The source gNodeB 22, wireless terminal 26 and node processor 30 of the communication system 20 are similar to Figure 6 、 Figure 11 and Figure 15 those of the present invention, wherein similar elements and functions have similar reference numerals. Figure 19 As shown, the source gNodeB 22 includes a node processor circuit ("node processor 30") and a node transceiver circuit 32, wherein the node transceiver circuit 32 includes a node transmitter 34 and a node receiver 36. The node processor 30 includes a node frame / signal scheduler / handler 50, a message generator 54, an RRC state machine 56, and a handover controller 60, wherein the handover controller 60 in turn includes a measurement analyzer 62, a conditional handover (CHO) determination unit 64, and a conditional handover configuration information generator 66 (19). The previous exemplary embodiment is similar to Figure 19 The difference between the exemplary embodiments and modes is that the node processor 30 further comprises a source node security context manager 90. The security context manager 90 in turn comprises a first security context generator 91 and a key set generator 92 for the target cell.

[0214] As in the previous exemplary embodiments and modes, Figure 19The wireless terminal 26 of the exemplary embodiment and mode of the present invention includes a terminal processor 40 and a terminal transceiver circuit 42, wherein the terminal transceiver circuit 42 in turn includes a terminal transmitter 44 and a terminal receiver 46. The terminal processor 40 also includes a terminal frame / signal processing program 52, a message processor 70, a switching unit 72 and a measurement controller 80. Although in Figure 19 It is not specifically shown in FIG, but it should be understood that Figure 15 In this way, the measurement controller 80 may further include a measurement initiation unit, a measurement result unit and a measurement report control unit. In addition, Figure 19 The terminal processor 40 is shown to include a terminal security context manager 94. The terminal security context manager 94 includes a terminal first context generator 95 and a terminal second context generator 96 for the target cell.

[0215] Figure 19 The exemplary embodiments and modes of the present invention take into account various aspects of context generation and processing in conjunction with switching. For example, Figure 19 The exemplary embodiments and modes of the present invention take into account that the security context may be changed / updated under certain conditions (such as during handover). Conditional handover or unconditional handover can be divided into one of the following types:

[0216] Inter-gNB handover: The target cell is controlled by a different gNB than the one controlling the current serving cell.

[0217] Intra-gNB handover: The target cell is controlled by the same gNB that controls the current serving cell.

[0218] Intra-cell handover: Some configuration parameters are changed while the UE stays in the current serving cell. This can be considered a handover without mobility.

[0219] In this context, non-conditional handover refers to a regular (normal) handover, in which the UE immediately attempts to access the target cell upon doing so. On the other hand, conditional handover is a handover that is configured prospectively, for example, in which the wireless terminal is configured for potential handover prior to the actual handover triggering condition or event, as explained in the previous embodiments.

[0220] While the UE remains in RRC_CONNECTED (or possibly RRC_INACTIVE), the AS security context may need to be updated due to UE mobility or other reasons. The AS security context update may be triggered by the radio access network (RAN). When triggered, the UE and the currently serving gNB (source gNB) may generate a new set of security keys. If the UE performs a handover to a target cell, this new set of security keys may be shared by the target gNB controlling the target cell. Herein, the set of parameters or information used to generate security keys for a non-conditional handover may be referred to as a first security configuration. In some example configurations, the first security configuration may be provided to the UE via a handover command when a handover is indicated or a security key update is required.

[0221] In an unconditional handover, the currently serving gNB may send a handover command to the UE. In one configuration, an RRCReconfiguration may be used to trigger an unconditional handover. Listing 9 shows an example RRCReconfiguration format for an unconditional handover.

[0222] List 9

[0223]

[0224]

[0225]

[0226]

[0227]

[0228] Upon receiving the RRCReconfiguration shown by way of example in Listing 9 above, the UE may perform the procedures as specified in 3GPP TS 38.331 and shown at least in part in Listing 10.

[0229]

[0230]

[0231] In one configuration, the MasterKeyUpdate information element (IE) shown by way of example in Listing 10 (and possibly in combination with the securityAlgorithmConfig IE) may be considered as an exemplary implementation of the first security configuration. Additionally, the ReconfigurationWithSync IE may include a RACH configuration indicating that the handover involves mobility (cell change and / or gNB change).

[0232] If the handover command indicates (e.g., the presence of the first security configuration), the UE may be requested to update the security context. For intra-gNB or inter-gNB handover, the updated security context may be used for the target cell during / after the handover procedure is performed. For example, Figure 20 As shown, according to 3GPP TS 33.501, which is incorporated herein by reference, the UE may use a K AMF K is derived from the parameter (one of the keys used for NAS security context) and the nextHopChainingCount (NCC) received in RRCReconfiguration. gNB (i.e., the master key for the AS security context). The derived K gNB Can be used to further generate subsequent keys (such as K according to TS 33.501 RRCint and K RRCenc ). An exemplary procedure for key derivation according to 3GPP TS 33.501 is at least partially described in Listing 11.

[0233]

[0234]

[0235]

[0236] Additionally, in some configurations, an intra-cell handover may be indicated to the UE only for the purpose of updating the AS security context. This action may be referred to as an "on-the-fly key change," which may fall into one of two cases: rekeying and key refreshing.

[0237] The rekeying scenario is initiated by the AMF. The AMF may use a new uplink NAS count (a counter handled by the Non-Access Stratum (NAS) layer, which is shared by the UE and the AMF) to rekey the key from the current K amf Create a new K gNB The derived K gNB The gNB may then send an RRC message (e.g., RRCReconfiguration) with a first security configuration, which includes (1) an indication that a new Kamf needs to be generated, and / or (2) an indication that a new KAMf needs to be generated based on KAMf. AMF Generate a new K gNB An indication (e.g., KeySetChangeIndicator = TRUE).

[0238] The key refresh is initiated by the currently serving gNB. If an unused {NH, NCC} pair provided by the AMF is available, the gNB can generate a new K from the next hop parameter NH. gNB, which is called “vertical derivation”. Otherwise, the gNB can be derived from the currently used K gNB Generate a new K gNB (called "horizontal export"). Vertical export is Figure 20 The vertical direction is performed in , while the horizontal export is performed in Figure 20 The gNB may then send an RRC message (e.g., RRCReconfiguration) including the first security configuration (e.g., nextHopChainingCount and KeySetChangeIndicator = FALSE for key derivation). The UE receiving the RRC message may generate a new K using vertical derivation or horizontal derivation based on the received NCC value and the stored NCC value. gNB That is, if the received NCC value is different from the saved NCC value, vertical export may be performed, otherwise horizontal export may be performed.

[0239] If the handover command does not include the first security configuration, the UE shall continue to use the current AS security context (i.e., the current AS key) after the handover. In some systems (such as 5G systems), an AS key update may not be required for intra-gNB handover. In this case, the UE can determine whether an AS key update is required, for example, by the presence of MasterKeyUpdate and possibly securityAlgorithmConfig in the RRCReconfiguration.

[0240] As previously mentioned, the "first security configuration" is described as a set of parameters or information used to generate security keys for non-conditional handover. On the other hand, and as used herein, the "second security configuration" includes a set of parameters or information to be used to generate a security context to be established upon or after performing a conditional handover to one of the candidate target cells configured in the CHO configuration. Figure 19 In the exemplary first embodiment and exemplary mode of the exemplary embodiment, in the previous embodiment (such as reference Figure 6 、 Figure 11 and / or Figure 15 The CHO configuration disclosed in one or more exemplary embodiments and modes described in the CHO configuration may also include a second security configuration to be used to generate a security context to be established when or after performing a conditional handover to one of the candidate target cells configured in the CHO configuration. Figure 19 In other exemplary implementations of the exemplary embodiments and modes, the second security configuration may be part of a message including a CHO configuration, but not part of the CHO configuration information element itself (e.g., in a different information element included in the message). Figure 21An exemplary format of at least some portions of a representative conditional handover configuration message including the second security configuration information is shown. Figure 22 As shown by way of example in FIG, the second security configuration may include:

[0241] The security algorithm to use (e.g. securityAlgorithmConfig)

[0242] Next hop chain count (e.g., nextHopChainingCount)

[0243] An indication that a new AS key set needs to be generated (e.g., KeySetChangeIndicator)

[0244] Similar to the first security configuration, a second security configuration for the candidate target cell may optionally be included in the CHO configuration. If the second security configuration is not present, the UE may continue to use the master key and subsequent keys used in the current serving cell after performing CHO to the candidate target cell.

[0245] In one exemplary configuration, Figure 23A As shown by way of example in FIG. 5 , a common second security configuration may be used for all candidate target cells in a CHO configuration.

[0246] In another exemplary configuration, Figure 23B As shown in the example, a cell-specific second security configuration may be configured for each candidate target cell.

[0247] In yet another exemplary configuration, Figure 23C As shown in the example, multiple second security configurations are configured, wherein each second security configuration can be used for one or a group of candidate target cells.

[0248] Listing 12-1 shows an exemplary format of a CHO configuration including a cell-specific second security configuration for each candidate target cell.

[0249] List 12-1

[0250]

[0251]

[0252]

[0253]

[0254] Listing 12-2 is an alternative format for a cell-specific second security configuration, where the CHO configuration CHOConfig may include one common second security configuration masterKeyUpdate, and each CHO configuration, such as CHOConfigNR, includes a flag indicating whether it is associated with the second common security configuration.

[0255] Listing 12-2

[0256]

[0257] exist Figure 19 In an exemplary embodiment and mode of the present invention, the source gNodeB 22 includes a node processor 30 and a node transmitter 34. The node processor 30 (specifically, a first security context generator 91) is configured to establish a first security context with the wireless terminal 26 using a first key set. The node processor 30 (e.g., a conditional handover configuration information generator 66 (19)) is configured to generate a configuration message comprising: (1) one or more conditional handover configurations, and (2) an indication of a key set to be used by the wireless terminal to establish a second security context at or after a handover configured by each of the one or more conditional handover configurations, depending on whether each of the one or more conditional handover configurations is configured with a security configuration. Each of the one or more conditional handover configurations includes at least one identity of a candidate target cell and at least one triggering condition. The key set used by the wireless terminal to establish the second security context at or after a handover configured by each of the one or more conditional handover configurations may be generated by a key set generator 92 for the target cell.

[0258] therefore, Figure 19 The source gNodeB 22 performs the following Figure 24 Example basic representative actions of the steps shown. Action 24-1 includes establishing a first security context with the wireless terminal using a first key set. Action 24-1 can be performed at least in part by a first security context generator 91. Action 24-2 includes generating a configuration message. The configuration message of action 24-2 (which can be generated by a key set generator 92 for a target cell) can include: (1) one or more conditional handover configurations, and (2) an indication of a key set to be used by the wireless terminal to establish a second security context at or after a handover configured by each of the one or more conditional handover configurations, depending on whether each of the one or more conditional handover configurations is configured with a security configuration.

[0259] exist Figure 19In an exemplary embodiment and mode of the present invention, a wireless terminal 26 (sometimes referred to as a UE) includes a terminal processor 40 and a terminal receiver 46. The terminal processor 40 of the wireless terminal 26 (specifically, a terminal security context manager 94) is configured to establish a first security context with a first wireless access node using a first key set. The terminal processor 40 (specifically, a handover unit 72) is configured to perform a conditional handover to a candidate target cell configured by one of the one or more conditional handover configurations if at least one trigger condition associated with the candidate target cell is satisfied. The terminal processor 40 (specifically, a terminal second context generator 96 for the target cell) is further configured to establish a second security context with a second wireless access node serving the candidate target cell based on whether the security configuration associated with the candidate target cell is configured by the configuration message.

[0260] therefore, Figure 19 The wireless terminal 26 performs the following Figure 25 Example basic representative actions of the steps shown. Action 25-1 includes establishing a first security context with a first wireless access node using a first key set. Action 25-2 includes performing a conditional handover to a candidate target cell configured by one of the one or more conditional handover configurations if the at least one trigger condition associated with the candidate target cell is satisfied. Action 25-3 includes establishing a second security context with a second wireless access node serving the candidate target cell based on whether the security configuration associated with the candidate target cell is configured by the configuration message.

[0261] Figure 26An example procedure for a UE with a security configuration for handover is shown. Thus, as act 26-0, the UE may establish a first security context with a first (source) gNB. The first security context may include a first key set for encryption and integrity protection. As act 26-1, the UE may receive a configuration message from the first gNB, the configuration message including one or more conditional handover configurations. Each conditional handover configuration may include at least one identity of a candidate target cell and at least one trigger condition. The configuration message of act 26-1 may also include an optional security configuration. If present, each security configuration may be associated with at least one of the conditional handover configurations. Act 26-2 includes determining whether at least one trigger condition associated with the candidate target cell is satisfied. If, in act 26-2, it is determined that at least one trigger condition associated with the candidate cell is satisfied, then, in act 26-3, the UE may perform a conditional handover to the candidate target cell. Upon or after performing the conditional handover of act 26-3, the UE may check the existence of the security configuration associated with the candidate target cell, in act 26-4. If the check in act 26-4 is positive, then as act 26-5, the UE may establish a second security context with the node controlling the candidate target cell (e.g., the target gNB) using a second key set derived from the associated security configuration. If the check in act 26-4 is negative, then as act 26-6, the UE may continue to establish a second security context with the second gNB using the first key set.

[0262] Figure 27An example procedure for a gNB for this embodiment is shown. Action 27-1 shows that the gNB may establish a first security context with the UE. The first security context may include a first key set for encryption and integrity protection. As action 27-1, the gNB may determine candidate target cells for CHO to be configured for the UE. As action 27-2, the gNB may also determine, for each candidate target cell, a key set to use, i.e., the first key set or an updated key set. As action 27-3, for each candidate target cell, the gNB may proactively perform handover coordination with the node controlling each candidate target cell. During handover coordination for each candidate target cell, if the updated key set is to be used, the gNB may generate a second key set and provide the second key set to the node. As action 27-4, the gNB may then generate and transmit a configuration message including the CHO configuration and, optionally, a second security configuration. Each conditional handover configuration may include at least one identity of the candidate target cell and at least one trigger condition. Each second security configuration, if present, may be associated with at least one of the conditional handover configurations. For each CHO configuration, if associated with one of the optional security configurations, the gNB may instruct the UE to derive the second key set upon or after conditional handover, otherwise the gNB may instruct the UE to continue using the first key set.

[0263] 5: Release CHO configuration based on security configuration

[0264] like Figure 19 As described in the previous sections and implementations of , a series of access layer, i.e., AS, security contexts, can be generated and established during the linking process, such as Figure 20 In addition, the second safety configuration can be used in the future; for example, not immediately, but only after the triggering condition switches.

[0265] There may be a situation where, after a second security configuration has been created, for one or more reasons, a further new security configuration must be created. In the case where a further new security context must be created, creating a further security configuration breaks into the key chain because creating a new key set for the further security configuration may invalidate the previously configured (unused) second security configuration. Therefore, in the case of creating a further security configuration, it may be necessary to release (deconfigure) or suspend (deactivate) other previously created CHO configurations.

[0266] Figure 28 An exemplary communication system 20 is shown in which a security context may also be employed in conjunction with handovers, and in which the validity of a handover configuration may be checked based on the security configuration for reasons such as generally described above. Figure 28A system 20 including a source gNodeB 22 , a wireless terminal 26 , and a candidate target node 28 is shown. Figure 28 The source gNodeB 22, wireless terminal 26 and node processor 30 of the communication system 20 are similar to Figure 6 、 Figure 11 、 Figure 15 and Figure 19 those of the present invention, wherein similar elements and functions have similar reference numerals. Figure 28 As shown, the source gNodeB 22 includes a node processor circuit ("node processor 30") and a node transceiver circuit 32, wherein the node transceiver circuit 32 includes a node transmitter 34 and a node receiver 36. The node processor 30 includes a node frame / signal scheduler / handler 50, a message generator 54, an RRC state machine 56, a handover controller 60, and a security context manager 90. As in the previous exemplary embodiments and modes, the handover controller 60 may include a measurement analyzer 62, a conditional handover (CHO) determination unit 64, and a conditional handover configuration information generator 66 (28). The previous exemplary embodiments and modes are similar to Figure 28 The difference between the exemplary embodiments and modes is that the node processor 30 further includes a node conditional handover validity checker 97. The node conditional handover validity checker 97 may be an integral part of or included in the handover controller 60 and may communicate and / or interact with the security context manager 90. The security context manager 90 includes a first security context generator 91 and a second key set generator 92 (28) that derives a second key set for establishing a second security context between the wireless terminal and a second radio access node serving the target cell.

[0267] As in the previous exemplary embodiments and modes, Figure 28 The wireless terminal 26 of the exemplary embodiment and mode of the present invention includes a terminal processor 40 and a terminal transceiver circuit 42, wherein the terminal transceiver circuit 42 in turn includes a terminal transmitter 44 and a terminal receiver 46. The terminal processor 40 also includes a terminal frame / signal processing program 52, a message processor 70, a switching unit 72 and a measurement controller 80. Although in Figure 28 It is not specifically shown in FIG, but it should be understood that Figure 15 and Figure 19 In this way, the measurement controller 80 may further include a measurement initiation unit, a measurement result unit and a measurement report control unit. In addition, Figure 28The terminal processor 40 is shown to include a terminal conditional handover validity checker 98. The terminal security context manager 94 includes a terminal first context generator 95 and a terminal second key generator 96 (28). The terminal second key generator 96 (28) uses the security configuration to derive a second key set for establishing a second security context with a second radio access node serving the target cell.

[0268] Figure 28 The exemplary embodiments and modes of the present invention take into account various aspects of context generation and processing in conjunction with switching, in particular checking the validity of the conditional switching configuration as described herein. For example, Figure 19 The exemplary embodiments and modes of the present invention take into account various exemplary and scenarios, because the following and corresponding Figures 29 to 33 Exemplary scenarios 5-1 to 5-4 illustrate exemplary situations where the CHO configuration needs to be released or can be saved. Figure 34 and Figure 35 The action can also be performed by Figure 28 Exemplary embodiments and modes of system execution.

[0269] Example Scenario 5-1: Reestablishment after RLF

[0270] Figure 29 An exemplary scenario is shown in which a UE experiences a radio link failure (RLF) with a current serving cell after the current serving cell (source cell) configures CHO for a candidate target cell. How to configure CHO for the UE with respect to the candidate target cell is reflected by actions 29-0 to 29-6', which are similar to Figure 7 Actions 7-0 to 7-6' are therefore not described further herein.

[0271] exist Figure 29In the scenario, after detecting RLF, the UE may perform a cell selection procedure, which results in finding cell A, also referred to herein as cell 29. As shown in actions 29-7 and 29-8, the UE may perform a RACH procedure (e.g., a random access preamble / response procedure), after which, as action 29-9, an RRCReestablishmentRequest message may be sent to cell A. Then, as action 29-10, cell A may communicate with the source cell for retrieving the UE's connection context, such as the UE context. Upon successful retrieval of the UE context, cell A may respond to the UE with an RRCReestablishment message as action 29-11. The RRCReestablishment message of action 29-11 may include a nextHopChainingCount information element that the UE will use for cell A. Using the nextHopChainingCount information element, as shown in action 29-12, the UE may then update K via vertical key derivation or horizontal key derivation. gNB Action 29-13 shows that the UE then sends an RRCReestablishmentComplete message to cell A.

[0272] In some systems (such as LTE and 5G RAN), a key update such as that shown in action 29-13 must always occur after a connection is reestablished, for example after action 29-12. In this case, the second security configuration for each candidate target cell configured by the CHO configuration may have to be invalidated. Figure 29 In the scenario described above, the UE may, for example, release all CHO configurations for all candidate target cells. In parallel, the gNB serving the source cell may also need to cancel CHO coordination, such as resource allocation, for the candidate target cells. In one exemplary configuration, upon receiving a context retrieval request from cell A, the gNB serving the source cell may, as action 29-15, send a CHO / HO cancel command to each gNB controlling a candidate target cell.

[0273] Upon or after receiving the RRCReestablishment message, as action 29-13, the UE may perform horizontal key derivation or vertical key derivation to create a new AS master key (i.e., K gNB ) and subsequent keys, as described in the previous implementation scheme.

[0274] Cell A may be a different cell from the source cell, or may be the same cell as the source cell. In the latter case, UE context retrieval may be performed as internal signaling. In addition, if cell A is one of the candidate target cells configured in the CHO configuration, the UE may perform a conditional handover (CHO), such as Figure 7 As shown in the example in , instead of the connection being re-established.

[0275] Example Scenario 5-2: Inter-gNB Handover

[0276] Figure 30 The scene has the same Figure 29 The scene is similar to the initial action 30-0 to 30-6'. However, in Figure 30 In the scenario of , after receiving the CHO configuration from the current serving cell (source cell) in action 30-6, the current serving cell instructs the UE to perform an unconditional handover to the target cell not included in the CHO configuration, i.e., cell B (also referred to as cell 29'). Figure 30 This may occur when the measurement report (depicted in action 30-3' in FIG) indicates that the signal from a cell not listed as a candidate target cell is getting stronger. Figure 30 The coordination of the unconditional handover to the target cell (cell B) not included in the CHO configuration is reflected by action 30-7. If cell B is under the control of another gNB, cell B and the UE may have to use a new AS master key and therefore perform an RRCReconfiguration procedure as shown in action 30-8 to indicate that the unconditional handover may include a first security configuration and thus force the UE to update the key, for example to generate a new AS master key and subsequent keys. The generation of the new AS master key in the form of a key update is reflected by action 30-9. Figure 29 As described in the previous exemplary scenario, the UE may generate the AS master key through horizontal key derivation or vertical key derivation based on the value of the NCC included in the RRCReconfiguration and the saved (currently used) NCC.

[0277] Similar to example scenario 5-1, in the event that the UE derives a new master key due to a non-conditional gNB handover, as shown in action 30-9, any secondary security configuration received by the UE in the CHO configuration may become invalid, which may invalidate the CHO configuration for all candidate target cells. The UE may release the saved CHO configuration. Similarly, as shown in action 30-10, the source cell may send a CHO / HO cancel command to each gNB controlling a candidate target cell. Thereafter, the UE may participate in a random access procedure towards cell B, as shown in the random access preamble, random access response, and RRCReconfigurationComplete message of corresponding actions 30-11 to 30-13, respectively.

[0278] Example Scenario 5-3: Immediate Key Change

[0279] In some cases, the network, such as a gNB or a core network entity (such as the AMF), may initiate a key update. This procedure may also be referred to as an intra-cell handover without mobility, or an on-the-fly key change / update procedure. There are two types of networked on-the-fly key update procedures:

[0280] The key regeneration procedure can be initiated by the current serving AMF. The AMF can use the new uplink NAS count (a counter handled by the Non-Access Stratum (NAS) layer, which is shared by the UE and the AMF) to regenerate the key from the current K amf Create a new K gNB The derived K gNB Sent to the current serving gNB, and then the gNB can send an RRC message (such as RRCReconfiguration), which includes (1) indicating that a new K amf (e.g., the field K_AMF_change_flag included in the nas-Container) and / or (2) indicating the need for K-based amf To generate a new K gNB An indication (e.g., KeySetChangeIndicator = TRUE).

[0281] The key refresh procedure can be initiated by the current serving gNB. If an unused {NH, NCC} pair provided by the AMF is available, the gNB can generate a new K from the NH. gNB , that is, vertical export. Otherwise, the current serving gNB can be derived from the currently used K gNB Generate a new K gNB, i.e. horizontal derivation. Then, the gNB may send an RRC message including NCC and KeySetChangeIndicator=FALSE, such as RRCReconfiguration. The UE receiving the RRC message may generate a new K using vertical derivation or horizontal derivation based on the received NCC value and the stored NCC value. g NB.

[0282] Figure 31 An exemplary scenario is shown, in which, when configuring CHO to a candidate target cell (cell A), as action 31-7, the current serving cell (source cell) may send an RRCReconfiguration message including a masterKeyUpdate information element including values ​​for at least the NCC and the KeySetChangeIndicator. The UE may then respond with an RRCReconfigurationComplete message, as shown in action 31-8. As action 31-9, the UE may then release all CHO configurations, e.g., the CHO configuration for cell A, and other configurations, if any. In parallel, as action 31-10, the source cell may initiate a HO cancellation procedure to release the retained CHO coordination in the candidate target cell (e.g., cell A). Figure 31 In the exemplary scenario of FIG. 3 , actions 31 - 0 to 31 - 6 are substantially the same as corresponding actions in other scenarios, such as actions 29 - 0 to 29 - 6 ′.

[0283] Example Scenario 5-4: Intra-gNB Handover

[0284] Intra-gNB / eNB handover is a handover between two cells controlled by a gNB 22(32). Figure 32 As shown, a handover can occur between the source cell 23 and cell A (also referred to as cell 29). Figure 32 In the exemplary scenario of , it is assumed that the UE has been configured with a CHO configuration with one or more candidate target cells. In other words, actions 32-0 to 32-6, which are essentially the same as actions 29-0 to 29-6', respectively, have been performed. Action 32-4 shows that the gNB 22 (32) has made a handover decision to handover to cell A 29. Therefore, cell A performs handover coordination, as shown in action 32-5. However, in Figure 32 In the exemplary scenario of K gNB The key update of K can be performed after the intra-gNB handover. In other words, action 32-7 shows that the information element (such as masterKeyChange) is included in the message announcing the handover and the key update of K is provided. gNBAfter receiving the handover notification message, the RACH procedure reflected by the random access preamble message of action 32-8 and the random access response message of action 32-9 is performed. Thereafter, after the UE sends the RRCReconfigurationComplete message of action 32-11, if conditional handover coordination was previously configured, cell A 29 can cancel the conditional handover coordination by participating in the handover cancellation action 32-12.

[0285] In other deployment scenarios, the network operation policy may allow the same K gNB and subsequent keys.

[0286] In the exemplary intra-gNB scenario described herein, it is assumed that the UE has already been configured with a CHO configuration with one or more candidate target cells. In other words, actions 32-0 to 32-7, which are substantially the same as actions 29-0 to 29-7, respectively, have been performed. Upon successful handover to the target cell, the target cell may be one of the candidate target cells (for conditional handover) or may be another cell (for non-conditional handover), if the UE is allowed to use the current K gNB If a key update is required, the UE in this embodiment and mode may retain (not release) the CHO configuration. In this case, the gNB may also maintain the CHO configuration as the active configuration. While the UE / gNB may only release the CHO configuration for the target cell to which the UE successfully performed a conditional handover, the remaining CHO configurations may be retained. On the other hand, if a key update is required, the UE / gNB may release all CHO configurations when performing a handover in the same manner as previously disclosed for inter-gNB handover.

[0287] For example, consider a CHO configuration that includes cell A and cell B as candidate target cells, both of which are under the control of a single gNB, and where no key update is required for cell A or cell B. If the UE successfully performs a conditional handover to cell A, the UE / gNB can retain the CHO configuration for cell B while releasing the CHO configuration for cell A. The CHO configuration for cell A can be released because, after the conditional handover, the prospectively allocated radio resources for the UE at cell A may no longer be retained. Furthermore, before performing a conditional handover to either cell A or cell B, if the UE successfully performs an unconditional handover to cell C, which is also under the control of the gNB but is not a candidate target cell, the UE / gNB can retain the CHO configuration for both cell A and cell B after the unconditional handover.

[0288] In one configuration, the UE may determine the current K by the presence of the first or second security configuration. gNBWhether it will be used after the handover (and therefore the CHO configuration may be retained). Therefore, if the candidate target cell configured in the CHO configuration is associated with the second security configuration, the UE may consider that a key update is required for handover to the candidate target cell. On the other hand, if the second security configuration is not associated with the candidate target cell, the UE may not perform a key update after handover to the cell. In addition, in the case where the UE receives a handover command (e.g., RRCReconfiguration) from the current serving gNB (i.e., a normal handover or a non-CHO handover), if the handover command includes the first security configuration, the UE may perform a key update to generate a new K gNB , otherwise, the UE will continue to use the current key after the handover.

[0289] Figure 33 An exemplary UE procedure is shown, for example by Figure 28 The program is executed by the terminal processor 40.

[0290] Action 33-0 comprises the UE establishing a first security context with the first (source) gNB using the first key set.

[0291] Action 33-1 comprises the UE receiving a CHO configuration from the first gNB.

[0292] Action 33-2 comprises the UE checking whether it is experiencing a radio link failure (RLF).

[0293] Action 33-3 comprises the UE performing a cell selection procedure.After successful selection, the UE performs a re-establishment procedure, which will result in receiving an RRCReestablishment from the target cell including a security configuration for the target cell.

[0294] Action 33-4 comprises the UE checking whether it has received an RRCReconfiguration from the current serving gNB, which may trigger an intra-cell handover, an intra-gNB handover or an inter-gNB handover.

[0295] Action 33-5 comprises the UE checking whether one of the trigger conditions configured in the CHO configuration is met.

[0296] Action 33-6 includes the UE performing an unconditional handover or a conditional handover.

[0297] For non-conditional handover, the UE follows the configuration of the target cell provided by the received RRCReconfiguration. For conditional handover, the UE follows the configuration of the candidate target cell that meets the triggering conditions.

[0298] Action 33-7 includes the UE checking whether a security configuration is available, which forces the UE to generate a new K gNB (or KeNB ) and subsequent keys (second key set). In the case of a normal handover, this security configuration may optionally be present in the received RRCReconfiguration. In the case of a conditional handover, the security configuration for the target cell may optionally be present in the CHO configuration.

[0299] Act 33-8 comprises the UE establishing a second security context using the second key set.

[0300] Action 33-9 includes the UE releasing all CHO configurations.

[0301] Act 33-10 comprises the UE establishing a second security context using the first key set.

[0302] Action 33-11 includes the UE releasing the CHO configuration only for the target cell and retaining the CHO configuration for other candidate target cells.

[0303] Figure 34 Shown for Figure 28 Example implementations and modes, example procedures performed by the source gNodeB 22 (e.g., the current serving gNB).

[0304] Action 34-0 comprises the gNB establishing a first security context with the UE using the first key set.

[0305] Action 34-1 comprises the gNB determining a candidate target cell for CHO to be configured for the UE.

[0306] Action 34-2 comprises, for each candidate target cell, the gNB determining the key set to be used, i.e., the first key set or the new key set.

[0307] Action 34-3 comprises, for each candidate target cell, the gNB proactively performing handover coordination with the node controlling each candidate target cell.

[0308] Action 34-4 comprises the gNB transmitting the CHO configuration to the UE. The CHO configuration includes resource configuration, triggering conditions, and optional security configuration for each candidate target cell.

[0309] Action 34-5 involves the gNB checking whether the UE has already performed a re-establishment procedure (due to RLF). The gNB can identify the presence of a re-establishment procedure initiated by the UE when it receives a UE Context Retrieval Request from another node (inter-gNB re-establishment) or an RRCReestablishmentRequest from the UE (intra-gNB re-establishment).

[0310] Action 34-6 includes the gNB determining whether a (non-conditional) handover is required. This handover can be an intra-cell handover, an intra-gNB handover, or an inter-gNB handover.

[0311] Action 34-7 comprises the gNB transmitting an RRCReconfiguration to trigger a (non-conditional) handover of the UE.

[0312] Action 34-8 comprises the gNB checking whether the (unconditional) handover is associated with a security configuration.

[0313] Action 33-9 involves the gNB checking whether the UE has successfully performed a conditional handover to one of the candidate target cells. The gNB identifies a successful conditional handover if it receives a CHO success notification from one of the other gNBs (inter-gNB CHO) or receives an RRCReconfigurationComplete from one of the candidate target cells under the control of the (currently serving) gNB.

[0314] Action 34-10 comprises the gNB releasing all CHO configurations configured for the UE and performing handover cancellation for all other gNBs.

[0315] Action 34-11 comprises if the target cell of the (non-conditional) handover is one of the candidate target cells, the gNB releasing the CHO configuration for the target cell.

[0316] exist Figure 28 In an exemplary embodiment and mode of the present invention, the source gNodeB 22 includes a node processor 30 and a node transmitter 34. The node processor 30 (specifically a first security context generator 91) is configured to use a first key set to establish a first security context with the wireless terminal 26. The node transmitter 34 is configured to transmit a configuration message including one or more conditional handover configurations. Each of the one or more conditional handover configurations may include at least one identity of a candidate target cell and at least one trigger condition. The node processor 30 (e.g., a node conditional handover validity checker 97) is configured to determine the validity of the conditional handover configuration based on whether the handover to the target cell is configured with a security configuration when the wireless terminal performs a handover to the target cell. The node processor 30 (e.g., a second key set generator 92 (28)) is further configured to use the security configuration to derive a second key set for establishing a second security context between the wireless terminal and a second radio access node serving the target cell.

[0317] therefore, Figure 28 The source gNodeB 22 performs the following Figure 35Example basic representative actions of the steps shown. Action 35-1 includes establishing a first security context with the wireless terminal using a first key set. Action 35-2 includes transmitting a configuration message including one or more conditional handover configurations. Each of the one or more conditional handover configurations may include at least one identity of a candidate target cell and at least one trigger condition. Action 35-3 includes determining the validity of the conditional handover configuration based on whether the handover to the target cell is configured with the security configuration when the wireless terminal performs a handover to the target cell. Action 35-4 includes deriving a second key set for establishing a second security context between the wireless terminal and a second radio access node serving the target cell using the security configuration.

[0318] exist Figure 28 In an exemplary embodiment and mode of the present invention, a wireless terminal 26 (sometimes referred to as a UE) includes a terminal processor 40 and a terminal receiver 46. The terminal processor 40 (specifically a terminal security context manager 94) of the terminal processor 40 is configured to use a first key set to establish a first security context with a first wireless access node. The terminal receiver 46 is configured to receive a configuration message including one or more conditional handover configurations. The terminal processor 40 (e.g., a handover unit 72) is configured to perform a handover to a target cell. The terminal processor 40 (e.g., a terminal conditional handover validity checker 98) is configured to determine the validity of the conditional handover configuration based on whether the handover to the target cell is configured with the security configuration. The terminal processor 40 is further configured to use the security configuration to derive a second key set for establishing a second security context with a second wireless access node serving the target cell (e.g., using a terminal second key generator 96 (28)).

[0319] therefore, Figure 28 The wireless terminal 26 performs the following Figure 36 Example basic representative actions of the steps shown. Action 36-1 includes establishing a first security context with a first radio access node using a first key set. Action 36-2 includes receiving a configuration message including one or more conditional handover configurations. Each of the one or more conditional handover configurations may include at least one identity of a candidate target cell and at least one trigger condition. Action 36-3 includes determining the validity of the conditional handover configuration based on whether the handover to the target cell is configured with the security configuration. Action 36-4 includes deriving a second key set for establishing a second security context with a second radio access node serving the target cell using the security configuration.

[0320] 6: Provide secondary cell group configuration for dual connectivity

[0321] refer to Figure 37The described exemplary embodiments and modes disclose a dual connectivity (DC) scenario, where the master gNodeB 22 provides a secondary cell group (SCG) configuration to the wireless terminal for immediate use by the wireless terminal upon receipt. Figure 38 An exemplary diagram of dual connectivity (DC) is shown. Figure 38 As shown, when a UE is configured with DC operation, the UE may be configured with a group of one or more cells served by a master node (MN), namely a master cell group (MCG), and a group of one or more cells served by a secondary node (SN), namely a secondary cell group (SCG). Figure 38 In the figure, cells belonging to the master cell group (MCG) are shown with solid lines, while cells belonging to the secondary cell group (SCG) are shown with dotted lines. Figure 38 The depictions are for illustrative purposes only and are not intended to specify any particular cell placement or number.

[0322] In dual connectivity mode, a special cell can be defined in one or more cells in each cell group (MCG or SCG). This special cell can be used to obtain a timing reference for the corresponding cell group. The special cell for MCG can be referred to as PCell (primary cell), while the special cell for SCG can be referred to as PSCell (primary cell of SCG) or SpCell (special cell) of SCG. PCell can be a serving cell operating at the primary frequency, in which the UE can perform an initial connection establishment procedure and / or a connection re-establishment procedure. In addition, PSCell can be a serving cell in which the UE can perform a random access procedure (for example, in the case where the UE performs reconfiguration using a synchronization procedure). The cells other than the special cells in each cell group can be referred to as SCell (secondary cells). Therefore, with respect to dual connectivity, the secondary cell group (SCG) is a term given to a group of serving cells associated with a secondary RAN node.

[0323] Figure 37 An exemplary communication system 20 (37) is shown that provides a secondary cell group (SCG) configuration to a wireless terminal for immediate use by the wireless terminal upon receipt. Figure 37 The system 20 (37) is shown as including a source gNodeB 22, a wireless terminal 26, and a secondary cell group (SCG). Figure 37 In the exemplary embodiment and mode of FIG. 2 , the source gNodeB 22 acts as a master node (MN) and may therefore also be referred to as a master gNodeB 22 . Figure 37 The master gNodeB 22 and its node processor 30 and the wireless terminal 26 and its terminal processor 40 are similar to Figure 6 、 Figure 11 、 Figure 15 、 Figure 19 and Figure 28those of the present invention, wherein similar elements and functions have similar reference numerals. Figure 37 As shown, the source gNodeB 22 includes a node processor circuit ("node processor 30") and a node transceiver circuit 32, wherein the node transceiver circuit 32 includes a node transmitter 34 and a node receiver 36. The node processor 30 includes a node frame / signal scheduler / handler 50; a message generator 54; an RRC state machine 56; a handover controller 60; and a security context manager 90 (37). As in the previous exemplary embodiments and modes, the handover controller 60 may include a measurement analyzer 62, a conditional handover (CHO) determination unit 64, and a handover configuration information generator 66. Figure 37 In embodiments and modes, the message generator 54 may also be referred to as a configuration message generator 54 because it generates a configuration message that includes configuration information for immediate handover to one or more cells in a secondary cell group (SCG) to which the wireless terminal 26 may belong or have access.

[0324] When acting as a master node, the gNodeB 22 may control the connectivity of the wireless terminals it serves, including the wireless terminals 26. To this end, the node processor 30 of the gNodeB 22 is shown as including a master node connectivity controller 120. The master node connectivity controller 120 may execute an instance of connectivity control logic, a program, or a connectivity control routine for each wireless terminal 26 it serves. Figure 38 ), for each wireless terminal 26, an instance of the connectivity control program may include primary cell group connectivity logic 122 and secondary cell group connectivity control logic 124. Because certain aspects of the technology disclosed herein relate to secondary cell groups (SCGs), Figure 37 Also shown is that the secondary cell group connectivity control logic 124 may include or have access to network plan or network topology information 126. The network plan or network topology information 126 may include a database of nodes that may be eligible for inclusion in, or are actually included in, a secondary cell group (SCG) to which the wireless terminal 26 has access.

[0325] The security context manager 90 (37) of the master gNodeB 22 includes a first security context generator 91 and a second key generator 92 (37), which derives a second key for establishing a second security context and, thereby, derives one or more security keys for a radio connection with one or more secondary cells included in the secondary cell configuration.

[0326] As in the previous exemplary embodiments and modes, Figure 37The wireless terminal 26 of the exemplary embodiment and mode of the present invention includes a terminal processor 40 and a terminal transceiver circuit 42, wherein the terminal transceiver circuit 42 in turn includes a terminal transmitter 44 and a terminal receiver 46. The terminal processor 40 also includes a terminal frame / signal processing program 52, a message processor 70, a switching unit 72 and a measurement controller 80. Although in Figure 37 It is not specifically shown in FIG, but it should be understood that Figure 15 、 Figure 19 and Figure 28 In this way, the measurement controller 80 may further include a measurement initiation unit, a measurement result unit and a measurement report control unit. In addition, Figure 37 The terminal processor 40 is shown as including a terminal security context manager 94.

[0327] The wireless terminal 26 includes a connection controller 130, which may be implemented or included in the terminal processor 40. Figure 37 The wireless terminal 26 may be able to utilize dual connectivity operation, and therefore the connection controller 130 is shown as including primary cell group connectivity logic 132 and secondary cell group connectivity control logic 134. As previously explained, a secondary cell group (SCG) may include a PSCell and other cells, such as SCells. As an exemplary aspect of the technology disclosed herein, the primary gNodeB 22 prompts the wireless terminal 26 to perform an immediate handover to one or more cells in the secondary cell group (SCG). Information related to the immediate handover of each cell in the secondary cell group (SCG) may be provided by the primary gNodeB 22 to the wireless terminal 26 in a configuration message 138 generated by the message generator 54. The configuration message 138 may also be referred to as a reconfiguration message 138. The primary gNodeB 22 provides the configuration message 138 so that the secondary cell group connectivity control logic 134 may instruct the handover unit 72 to perform a handover when the wireless terminal receives the configuration message 138. This information may also be referred to herein as configuration information. Configuration information for a secondary cell group (SCG) may be stored in a secondary cell group configuration memory 140 (37) to which the secondary cell group connectivity control logic 134 has access. For one or more cells in the secondary cell group (SCG) to which the wireless terminal 26 belongs, the secondary cell group configuration memory 140 (37) includes fields or records that are stored in Figure 37 14. It is shown as including: a configuration identification field 142; a PSCell field 144, and an optional security key utilization counter field 148.

[0328] The wireless terminal 26 also includes a terminal security context manager 94. The terminal security context manager 94 in turn includes a terminal first context generator 95 and a terminal second key generator 96 (37). The terminal second key generator 96 (37) derives one or more security keys for radio connections with one or more secondary cells included in the conditional secondary cell configuration.

[0329] Thus, the master gNodeB 22 includes a message generator 54 that can generate and transmit a configuration message 138 to the wireless terminal 26. The configuration message can include an SCG configuration with a PSCell configuration. The SCG configuration is preferably stored in a secondary cell group configuration memory 140 (37). The secondary cell group connectivity control logic 134 of the UE that receives the configuration message can begin synchronization with the configured PSCell and then establish a radio connection / bearer with the SCell in the SCG.

[0330] Figure 39 To show that Figure 37 Flowchart of representative general steps or actions performed by the primary gNodeB 22 of FIG. 39-1 includes establishing a first radio connection with a wireless terminal, such as the wireless terminal 26. Action 39-2 includes transmitting a reconfiguration message including the secondary cell group configuration. An example of such a reconfiguration message (also referred to as a "configuration message") is Figure 37 13. The configuration message 138 shown. As previously explained, the configuration message 138 may be generated by the message generator 54 and transmitted to the wireless terminal 26 via the transmitter circuit 34. The configuration message 138 is received by the receiver circuit 46 of the wireless terminal 26 and processed by the message processor 70, which stores the contents of the configuration message 138 in the conditional secondary cell configuration memory 140 (37). The configuration message 138 may include a secondary cell group configuration, which in turn includes the identity of a primary secondary cell that may be used for dual connectivity (DC) (stored in the PSCell field 144). The secondary cell group configuration included in the configuration message 138 is configured to instruct the wireless terminal 26 to establish a second radio connection with a secondary access node that serves the primary secondary cell included in the secondary cell configuration upon receipt of the configuration message 138.

[0331] Figure 40 To show that Figure 37 Flowchart of representative general steps or actions performed by the wireless terminal 26 of FIG. Action 40 - 1 comprises establishing a first radio connection with a primary access node (eg, with a primary gNodeB 22 ).

[0332] Action 40-2 includes receiving a reconfiguration message including a secondary cell group configuration. The secondary cell group configuration may include the identity of a primary and secondary cell that may be used for dual connectivity (DC) (stored in the PSCell field 144). The secondary cell group configuration may be configured to instruct the wireless terminal to establish a second radio connection with a secondary access node serving the primary and secondary cells upon receiving the configuration message 138, e.g., substantially immediately upon receiving and processing the configuration message 138.

[0333] The following describes exemplary scenarios for the generation of configuration messages 138 (also referred to as reconfiguration messages 138), as well as examples of how configuration messages 138 may be structured or encapsulated within other messages. For example, Figure 41 and Table 1 provide an exemplary scenario / procedure for adding a secondary node, while Figure 42 and Table 2 provide exemplary situations / procedures for modifying the current SCG configuration within the same SN.

[0334] 3GPP TS 37.340 specifies the procedure for adding a (newly configured) secondary node (ie, adding a new SCG configuration), such as Figure 41 shown. Figure 40 The messages, actions and signals are basically described in Table 1 below:

[0335]

[0336]

[0337] TS 37.340 also describes the procedure for modifying the current SCG configuration within the same SN, such as Figure 42 and Table 2 in the text.

[0338]

[0339]

[0340] like Figure 41 / Figure 42 As shown in step 3 of , the RRCReconfiguration message (ie, the MN RRCReconfiguration message) may be used to configure the UE with the new / modified SCG. Figure 41 / Figure 42 As described in step 2 of , the MNRRCReconfiguration message may encapsulate another RRCReconfiguration message (ie, SN RRCReconfiguration message) provided by the SN and including the SCG configuration. Listing 13 is an exemplary format of the RRCReconfiguration message.

[0341]

[0342]

[0343]

[0344]

[0345]

[0346] In this example, it should be understood that, for the MN RRCReconfiguration message, the information element mrdc-SecondaryCellGroupConfig may be used to encapsulate the SN RRCReconfiguration message, and the encapsulated SN RRCReconfiguration message may include the information element secondaryCellGroup for SCG configuration.

[0347] As mentioned in Section 4 "Security Configuration for Conditional Handover Configuration", the terminal and network entities may need to protect user / signaling data from security attacks by applying encryption and integrity protection. The same may be true for radio bearers using SCG. As specified in 3GPP TS 33.401 and / or TS 33.501, an exemplary configuration of the security mechanism for a secondary cell group (SCG) may include an access stratum AS, a secondary node SN for deriving a master AS key for the secondary node (e.g., a key K SN ) key derivation scheme.

[0348] Figure 43 Shown for K SN When the master gNodeB 22 decides to add a new secondary node SN 160 or a new secondary cell group SCG, or when the master gNodeB 22 updates the security key used in the current active SN / SCG, the master gNodeB 22 may use Figure 43 An exemplary scheme of . Figure 43 The master gNodeB 22, for example the secondary key generator 92 (37) of the master gNodeB 22, is shown, which calculates K SN .like Figure 43 As shown, the secondary key generator 92 (37) may include a secondary key derivation function 150 that may receive the currently active AS master key 152 (K gNB) and a counter as input to a key derivation function (KDF), such as SK counter 154. The secondary key derivation function 150 uses the input of the currently active AS master key 152 and the SK counter 154 to derive the secondary node key K SN 156. The SK counter 154 may also be referred to as an SN counter or an SCG counter. The SK counter 154 may be selected by the master gNodeB 22 and used to SN New input in the export to ensure further from K in SN SN Other security keys derived will not be reused with the same input parameters. Other security keys may be used for ciphering and integrity protection of the radio bearers of the SN. The secondary node key K may be derived in the primary gNodeB 22 using the SN add request for SN addition. sn 156 is sent to the secondary node 160, such as Figure 41 As shown by way of example in , or for SN modification request update of SN key, such as Figure 42 This is shown in the example.

[0349] The master gNodeB 22 may send the SK counter to the wireless terminal 26 using an RRCReconfiguration message (see Listing 13). Figure 43 Also shown is the wireless terminal 26, and the auxiliary key generator 96 (37), which is specifically shown to include a key derivation function 170. The key derivation function 170 receives inputs received from the master gNodeB 22, for example in an RRCReconfiguration message, including a SK counter 172, and the currently active AS key K gNB 174. Upon receiving the RRCReconfiguration message, the secondary key generator 96 (37) may use the currently active AS key K shared with the primary gNodeB 22 gNB 174 and the received SK counter 172 are used as inputs to the key derivation function 170 to derive the secondary key K SN 176 , the secondary key may be used to derive other security keys to be used for encryption and integrity protection of radio bearers of the secondary node SN 160 .

[0350] therefore, Figure 37 and Figure 43 It is shown that the secondary cell group configuration is associated with a designated counter (such as an SK counter), and the counter can be used to calculate one or more security keys for the radio connection with the secondary cells included in the secondary cell group configuration. Figure 43shows how, in the master gNodeB 22, the input SK counter 154 may be used by the secondary key derivation function 150 to calculate the secondary node key K SN 156, and how, in the wireless terminal 26, the SK counter 172 may be used by the key derivation function 170 to calculate the secondary key K SN 176.

[0351] 7: Conditional PSCell Add / Modify Configuration

[0352] Some of the previous exemplary embodiments and modes discussed conditional handover, where one or more candidate target cells (candidate PCells) may be configured to the UE with associated one or more triggering conditions. Figure 37 The exemplary embodiments and modes of the present invention describe, for example, providing a secondary cell group (SCG) configuration for dual connectivity, wherein a handover involving a secondary cell group (SCG) occurs automatically upon receiving a configuration message carrying the secondary cell group (SCG) configuration information. On the other hand, Figures 44 to 46 The exemplary embodiments and modes of the present invention disclose configurations for conditional PSCell addition / modification. For conditional PSCell addition, the master gNodeB 22 may configure the wireless terminal 26 with a candidate PSCell associated with at least one triggering condition. When the triggering condition is met, the UE may perform the aforementioned SN addition procedure. Figure 44 In the exemplary embodiment and mode of conditional PSCell modification (change), a wireless terminal 26 currently establishing an SCG radio connection / bearer with a SN may be configured with a candidate PSCell associated with at least one triggering condition. Figure 44 In the case of , the wireless terminal 26 can execute the aforementioned SN modification procedure when it is determined that the trigger condition is met. Figure 44 In one exemplary implementation of the embodiments and modes, the trigger condition may be one or a combination of the previously disclosed trigger conditions for conditional handover (CHO). In addition, for conditional PSCell modification, the candidate PSCell may be served by the SN with which the UE is currently communicating (intra-SN PSCell) or by a different SN (inter-SN PSCell).

[0353] Depend on Figures 44 to 46The exemplary embodiments and modes of the present invention illustrate a configuration for conditional PSCell addition / modification of a secondary cell group (SCG) including one PSCell and zero or more SCells. In a sense, PSCell addition / modification can also be considered a "handover" to a secondary cell group (SCG), so at some junctures, the terms "PSCell addition / modification" and "handover to an SCG" may be used interchangeably herein, as may the terms "configuration for conditional PSCell addition / modification" and "configuration for conditional handover to an SCG."

[0354] Figure 44 An exemplary communication system 20 (42) is shown that provides a configuration for conditional PSCell addition / modification. Figure 44 The system 20 (44) is shown as including a source gNodeB 22, a wireless terminal 26, and a secondary cell group (SCG). Figure 44 In the exemplary embodiment and mode of FIG. 2 , the source gNodeB 22 acts as a master node (MN) and may therefore also be referred to as a master gNodeB 22 . Figure 44 The master gNodeB 22 and its node processor 30 and the wireless terminal 26 and its terminal processor 40 are similar to Figure 6 、 Figure 11 、 Figure 15 、 Figure 19 、 Figure 28 and Figure 37 those of the present invention, wherein similar elements and functions have similar reference numerals. Figure 44 As shown, the source gNodeB 22 includes a node processor circuit ("node processor 30") and a node transceiver circuit 32, wherein the node transceiver circuit 32 includes a node transmitter 34 and a node receiver 36. The node processor 30 includes a node frame / signal scheduler / handler 50; a message generator 54; an RRC state machine 56; a handover controller 60; and a security context manager 90 (44). As in the previous exemplary embodiments and modes, the handover controller 60 may include a measurement analyzer 62, a conditional handover (CHO) determination unit 64, and a conditional handover configuration information generator 66. Figure 44 In embodiments and modes, the message generator 54 may also be referred to as a conditional configuration message generator 54 because it generates a configuration message that includes configuration information regarding conditional switching to an SCG, such as PSCell addition / modification of a secondary cell group (SCG) and an optional SCell (if configured) for a wireless terminal 26 to which it may belong or have access.

[0355] When acting as a master node, the gNodeB 22 may control the connectivity of the wireless terminals it serves, including the wireless terminals 26. To this end, the node processor 30 of the gNodeB 22 is shown as including a master node connectivity controller 120. The master node connectivity controller 120 may execute an instance of connectivity control logic, a program, or a connectivity control routine for each wireless terminal 26 it serves. Figure 38 ), for each wireless terminal 26, an instance of the connectivity control program may include primary cell group connectivity logic 122 and secondary cell group connectivity control logic 124. Because certain aspects of the technology disclosed herein relate to secondary cell groups (SCGs), Figure 44 Also shown is the secondary cell group connectivity control logic 124, which may include or have access to network plan or network topology information 126. The network plan or network topology information 126 may include a database of nodes that may be eligible for inclusion in, or are actually included in, a secondary cell group (SCG) to which the wireless terminal 26 has access. The secondary cell group connectivity control logic 124 may also include conditional handover triggering logic 128. The conditional handover triggering logic 128 may include intelligence for generating conditions for handover to an SCG, e.g., triggering conditions for one or more secondary cells included in the secondary cell group (SCG) of the wireless terminal 26. Such triggering conditions may be the same or different for different cells included in the secondary cell group (SCG).

[0356] The security context manager 90 (44) of the master gNodeB 22 includes a first security context generator 91 and a second key generator 92 (44), which derives a second key for establishing a second security context and, thereby, derives one or more security keys for a radio connection with one or more secondary cells included in the conditional secondary cell configuration.

[0357] As in the previous exemplary embodiments and modes, Figure 44 The wireless terminal 26 of the exemplary embodiment and mode of the present invention includes a terminal processor 40 and a terminal transceiver circuit 42, wherein the terminal transceiver circuit 42 in turn includes a terminal transmitter 44 and a terminal receiver 46. The terminal processor 40 also includes a terminal frame / signal processing program 52, a message processor 70, a switching unit 72 and a measurement controller 80. Although in Figure 44 It is not specifically shown in FIG, but it should be understood that Figure 15 、 Figure 19 、 Figure 28 and Figure 37 In this way, the measurement controller 80 may further include a measurement initiation unit, a measurement result unit and a measurement report control unit. In addition, Figure 44The terminal processor 40 is shown as including a terminal security context manager 94 (42).

[0358] The wireless terminal 26 includes a connection controller 130, which may be implemented or included in the terminal processor 40. Figure 44 The wireless terminal 26 may be able to utilize dual connectivity operation, and therefore the connection controller 130 is shown as including primary cell group connectivity logic 132 and secondary cell group connectivity control logic 134. As previously explained, a secondary cell group (SCG) may include a PSCell and other cells, such as an SCell. As an exemplary aspect of the technology disclosed herein, the primary gNodeB 22 may permit and / or authorize the wireless terminal 26 to perform a conditional handover to the SCG, and the conditional handover to the SCG may involve the PSCell and, if configured, the SCell in the secondary cell group (SCG). Information related to the conditional handover to the SCG for each cell in the secondary cell group (SCG) may be provided by the primary gNodeB 22 to the wireless terminal 26 in a configuration message 138 (44) generated by the message generator 54. The configuration message 138 (44) may also be referred to as a reconfiguration message 138 (44) or a conditional configuration message. The master gNodeB 22 provides a configuration message 138 (44) so ​​that the secondary cell group connectivity control logic 134 can instruct the handover unit 72 to perform a conditional handover to the SCG when the condition specified in the configuration message 138 (44) occurs. This information may also be referred to herein as conditional configuration information. Configuration information for each cell in the secondary cell group (SCG) may be stored in a conditional secondary cell configuration memory 140 (44) to which the secondary cell group connectivity control logic 134 has access. For one or more cells in the secondary cell group (SCG) to which the wireless terminal 26 belongs, the secondary cell group configuration memory 140 (44) includes fields or records that are stored in the conditional secondary cell configuration memory 140 (44). Figure 44 14. It is shown as including: a configuration identification field 142; a PSCell field 144, a trigger condition field 146, and an optional security key utilization counter field 148.

[0359] The wireless terminal 26 also includes a terminal security context manager 94. The terminal security context manager 94 in turn includes a terminal first context generator 95 and a terminal second key generator 96 (44). The terminal second key generator 96 (44) derives one or more security keys for radio connections of one or more secondary cells included in the conditional secondary cell configuration.

[0360] Thus, the master gNodeB 22 includes a message generator 54 that can generate and transmit a configuration message 138 (44) to the wireless terminal 26, which can include an SCG configuration with a PSCell configuration. The SCG configuration is preferably stored in a conditional secondary cell configuration memory 140 (44). The secondary cell group connectivity control logic 134 of the UE that receives the configuration message can begin synchronization with the configured PSCell and then establish a radio connection / bearer with the SCell in the SCG after the wireless terminal 26 determines that a trigger condition associated with the SCG configuration is satisfied.

[0361] Figure 45 To show that Figure 44 Flowchart of representative general steps or actions performed by the master gNodeB 22 of FIG. 45. Action 45-1 includes establishing a first radio connection with a wireless terminal, such as the wireless terminal 26. Action 45-2 includes transmitting a reconfiguration message including a conditional secondary cell configuration. An example of such a reconfiguration message (also referred to as a "configuration message") is Figure 44 14. The configuration message 138(44) is shown. As previously explained, the configuration message 138(44) may be generated by the message generator 54 and transmitted to the wireless terminal 26 via the transmitter circuitry 34. The configuration message 138(44) is received by the receiver circuitry 46 of the wireless terminal 26 and processed by the message processor 70, which stores the contents of the configuration message 138(44) in the conditional secondary cell configuration memory 140(44). The configuration message 138(44) may include a conditional secondary cell group configuration, which in turn may include the identities of candidate primary and secondary cells that may be used for dual connectivity (DC) (stored in the PSCell field 144). In addition, the conditional secondary cell configuration may be associated with at least one trigger condition stored in the trigger condition field 146.

[0362] The conditional secondary cell configuration included in the configuration message 138 (44) is configured to instruct the wireless terminal 26 to establish a second radio connection with a secondary access node that serves a candidate primary secondary cell included in the conditional secondary cell configuration if at least one trigger condition associated with the conditional secondary cell configuration is met.

[0363] Figure 46 To show that Figure 44 Flowchart of representative general steps or actions performed by the wireless terminal 26 of FIG. Action 46 - 1 comprises establishing a first radio connection with a primary access node (eg, with a primary gNodeB 22 ).

[0364] Action 46-2 includes receiving a reconfiguration message including a conditional secondary cell configuration. The conditional secondary cell configuration may include the identities of candidate primary and secondary cells that may be used for dual connectivity (DC) (stored in the PSCell field 144). The conditional secondary cell configuration may be associated with at least one trigger condition stored in the trigger condition field 146. The conditional secondary cell configuration may be configured to instruct the wireless terminal to establish a second radio connection with a secondary access node, which serves the candidate primary and secondary cells included in the conditional secondary cell configuration, if at least one trigger condition associated with the conditional secondary cell configuration is satisfied. Thus, action 46-3 includes the wireless terminal 26 establishing a second radio connection with a secondary access node, which serves the candidate primary and secondary cells included in the conditional secondary cell configuration, if at least one trigger condition associated with the conditional secondary cell configuration is satisfied.

[0365] As can be understood from the foregoing, Figure 44 The configuration message 138 (44) of the embodiment and mode relates to the conditional configuration of the secondary cell group (SCG), and is used for Figure 37 Configuration of the secondary cell group (SCG) for the embodiment and mode occurs upon receipt of the configuration message 138. However, additional Figure 37 The exemplary embodiments and modes of the previous embodiment of the present invention provide an understanding of exemplary cases of the generation of configuration messages 138 (44) and examples of how configuration messages 138 (44) may be constructed or encapsulated within other messages. For example, Figure 41 and Table 1 provide an exemplary scenario / procedure for adding a secondary node, while Figure 44 and Table 2 provide exemplary situations / procedures for modifying the current SCG configuration within the same SN.

[0366] Listing 14 shows an exemplary format for the configuration of conditional PSCell addition / modification, where the MN RRCReconfiguration message encapsulating the SNRRCReconfiguration message may include a list of triggering conditions. It should be understood that the MN RRCReconfiguration message may be substantially as described in relation to Figure 37 The embodiments and modes disclosed herein further include this list of trigger conditions.

[0367] exist Figure 44In one exemplary implementation of the embodiments and modes, upon receiving the MNRRCReconfiguration message, the wireless terminal 26 may perform a conventional, e.g., unconditional, legacy, or substantially immediate, PSCell addition / modification if the message does not include a triggering condition. Otherwise, the wireless terminal 26 may store the configuration for the PSCell addition / modification along with the triggering condition in the conditional secondary cell configuration memory 140 (44) without activating the configuration, and perform the specified PSCell addition / modification when at least one triggering condition is met.

[0368] In another configuration, the (MN or SN)RRCReconfiguration message may include a separate information element, not shown in Listing 14, indicating whether the configuration for PSCell addition / modification is conditional. In this case, the wireless terminal 26 may determine whether to perform a normal PSCell addition / modification or a conditional PSCell addition / modification based on the separately provided information element.

[0369]

[0370]

[0371]

[0372]

[0373]

[0374]

[0375]

[0376] In one exemplary implementation, Figure 44 The system 30 (44) of the embodiment and mode of the present invention also includes a mechanism for deploying a security configuration that can be used for the candidate PSCell, such as in Figure 37 and Figure 43That is, the MN RRCReconfiguration message 138 (44) may include an information element corresponding to sk-Counter to be applied to the conditional PSCell addition / modification configuration included in the encapsulated SNRRCReconfiguration message. The wireless terminal 26 receiving the MN RRCReconfiguration message may store the received SK counter in the security key utilization counter field 148 of the conditional secondary cell configuration memory 140 (44) and use it before or when performing the configured PSCell addition / modification, such as, for example Figure 43 and the calculation of K for candidate PSCell disclosed in the description of this article SN .

[0377] 8: Conditional PSCell add / modify configuration for multiple candidate PSCells

[0378] Figure 47 1 shows an exemplary embodiment and mode in which the wireless terminal 26 can be configured with multiple candidate PSCells for conditional PSCell addition / modification. Figure 47 Two secondary cell groups (SCGs) are shown: a first secondary cell group (SCG) including an unpopulated PSCell and two unpopulated Scells, and a second secondary cell group (SCG) including a populated PSCell and two unpopulated Scells. Figure 47 In one exemplary implementation of the embodiments and modes, each candidate PSCell configuration may be associated with one or more specified triggering conditions. Figure 47 In another exemplary implementation of the embodiments and modes, a trigger condition may be shared by all or some of the candidate PSCells, for example, by being shared by populated and unpopulated PSCells. During configuration, the wireless terminal 26 may evaluate the trigger condition and perform PSCell addition / modification for the PSCells that meet the trigger condition, such as Figure 44 As disclosed in the embodiments and modes.

[0379] Figure 47 The system 20 (47) is shown as including a source gNodeB 22, a wireless terminal 26, and a plurality of secondary cell groups (SCGs). Figure 47 In the exemplary embodiment and mode of FIG. 2 , the source gNodeB 22 acts as a master node (MN) and may therefore also be referred to as a master gNodeB 22 . Figure 47 The master gNodeB 22 and its node processor 30 and the wireless terminal 26 and its terminal processor 40 are similar to Figure 6 、 Figure 11 、 Figure 15 、 Figure 19 、 Figure 28 、 Figure 37 and Figure 44 those of the present invention, wherein similar elements and functions have similar reference numerals. Figure 47 As shown, the source gNodeB 22 includes a node processor circuit ("node processor 30") and a node transceiver circuit 32, wherein the node transceiver circuit 32 includes a node transmitter 34 and a node receiver 36. The node processor 30 includes a node frame / signal scheduler / handler 50; a message generator 54; an RRC state machine 56; a handover controller 60; and a security context manager 90 (47). As in the previous exemplary embodiments and modes, the handover controller 60 may include a measurement analyzer 62, a conditional handover (CHO) determination unit 64, and a conditional handover configuration information generator 66. Figure 47 In the embodiment and mode, the message generator 54 can also be referred to as a conditional configuration message generator 54 because it generates a configuration message for the wireless terminal 26 to belong to or have access to one or more cells in an SCG in the multi-secondary cell group (SCG), and the configuration message includes configuration information for conditional switching to the SCG.

[0380] When acting as a master node, the gNodeB 22 may control the connectivity of the wireless terminals it serves, including the wireless terminals 26. To this end, the node processor 30 of the gNodeB 22 is shown as including a master node connectivity controller 120. The master node connectivity controller 120 may execute an instance of connectivity control logic, a program, or a connectivity control routine for each wireless terminal 26 it serves. Figure 38 ), for each wireless terminal 26, an instance of the connectivity control program may include primary cell group connectivity logic 122 and secondary cell group connectivity control logic 124. Because certain aspects of the technology disclosed herein relate to secondary cell groups (SCGs), Figure 47Also shown is the secondary cell group connectivity control logic 124, which may include or have access to network plan or network topology information 126. The network plan or network topology information 126 may include a database of nodes that may be eligible for inclusion in, or are actually included in, a secondary cell group (SCG) to which the wireless terminal 26 has access. The secondary cell group connectivity control logic 124 may also include conditional handover triggering logic 128. The conditional handover triggering logic 128 may include intelligence for generating conditions for handover to an SCG, e.g., triggering conditions for handover to one or more secondary cells included in a secondary cell group (SCG) for the wireless terminal 26. Such triggering conditions may be the same or different for different cells included in the plurality of secondary cell groups (SCGs).

[0381] The security context manager 90 (47) of the master gNodeB 22 includes a first security context generator 91 and a second key generator 92 (47) that derives a second key for establishing a second security context and, thereby, derives one or more security keys for a radio connection with one or more secondary cells included in the conditional secondary cell configuration.

[0382] As in the previous exemplary embodiments and modes, Figure 47 The wireless terminal 26 of the exemplary embodiment and mode of the present invention includes a terminal processor 40 and a terminal transceiver circuit 42, wherein the terminal transceiver circuit 42 in turn includes a terminal transmitter 44 and a terminal receiver 46. The terminal processor 40 also includes a terminal frame / signal processing program 52, a message processor 70, a switching unit 72 and a measurement controller 80. Although in Figure 47 It is not specifically shown in FIG, but it should be understood that Figure 15 、 Figure 19 、 Figure 28 、 Figure 37 and Figure 44 In this way, the measurement controller 80 may further include a measurement initiation unit, a measurement result unit and a measurement report control unit. In addition, Figure 47 The terminal processor 40 is shown as including a terminal security context manager 94 (47).

[0383] The wireless terminal 26 includes a connection controller 130, which may be implemented or included in the terminal processor 40. Figure 47The wireless terminal 26 may be able to utilize dual connectivity operation, and thus the connection controller 130 is shown as including primary cell group connectivity logic 132 and secondary cell group connectivity control logic 134. As previously explained, each of the multiple secondary cell groups (SCGs) may include a PSCell and other cells, such as SCells. As an exemplary aspect of the technology disclosed herein, the primary gNodeB 22 may permit and / or authorize the wireless terminal 26 to perform a conditional handover to the SCG, and the conditional handover to the SCG may involve any one of the cells in the involved secondary cell groups (SCGs). Information related to the conditional handover to the SCG for each of the multiple secondary cell groups (SCGs) may be provided by the primary gNodeB 22 to the wireless terminal 26 in a configuration message 138 (47) generated by the message generator 54. The configuration message 138 (47) may also be referred to as a reconfiguration message 138 (47) or a conditional configuration message. The master gNodeB 22 provides a configuration message 138 (47) so that the secondary cell group connectivity control logic 134 can instruct the handover unit 72 to perform a conditional handover to the SCG when the condition specified in the configuration message 138 (47) occurs. This information may also be referred to herein as conditional configuration information. Configuration information for each SCG in the plurality of secondary cell groups (SCGs) and for each cell in each secondary cell group (SCG) may be stored in a conditional secondary cell configuration memory 140 (47) to which the secondary cell group connectivity control logic 134 has access. For one or more cells in the plurality of secondary cell groups (SCGs) to which the wireless terminal 26 belongs, the conditional secondary cell configuration memory 140 (47) includes Figure 44 The fields or records shown in , include a configuration identification field 142 ; a PSCell field 144 , a trigger condition field 146 , and an optional security key utilization counter field 148 . Figure 47 Specifically shown is a conditional secondary cell configuration memory 140 (47) including fields or records associated with unpopulated secondary cell groups (SCGs) and fields or records associated with populated secondary cell groups (SCGs), and thus accommodating storage of multiple secondary cell group (SCG) configurations.

[0384] The wireless terminal 26 also includes a terminal security context manager 94. The terminal security context manager 94 in turn includes a terminal first context generator 95 and a terminal second key generator 96 (47). The terminal second key generator 96 (47) derives one or more security keys for radio connections with one or more secondary cells included in the conditional secondary cell configuration.

[0385] Thus, the master gNodeB 22 includes a message generator 54 that can generate and transmit a configuration message 138 (47) to the wireless terminal 26, which can include one or more SCG configurations with the PSCell configuration. The SCG configurations are preferably stored in the conditional secondary cell configuration memory 140 (47). The secondary cell group connectivity control logic 134 of the UE that receives the configuration message can begin synchronization with the configured PSCell and then establish a radio connection / bearer with the SCell in the SCG after the wireless terminal 26 determines that the trigger condition associated with the SCG configuration is met.

[0386] Figure 48 To show that Figure 47 Flowchart of representative general steps or actions performed by the master gNodeB 22 of FIG. 48-1 includes establishing a first radio connection with a wireless terminal, such as the wireless terminal 26. Action 48-2 includes transmitting a reconfiguration message including one or more conditional secondary cell configurations. An example of such a reconfiguration message (also referred to as a "configuration message") is Figure 47 14. The configuration message 138 (47) is shown. As previously explained, the configuration message 138 (47) may be generated by the message generator 54 and transmitted to the wireless terminal 26 via the transmitter circuit 34. The configuration message 138 (47) is received by the receiver circuit 46 of the wireless terminal 26 and processed by the message processor 70, which stores the contents of the configuration message 138 (47) in the conditional secondary cell configuration memory 140 (47). The configuration message 138 (47) may include configurations for one or more of the plurality of secondary cell groups (SCGs), each of which may include the identities of candidate primary secondary cells that may be used for dual connectivity (DC) (stored in the PSCell field 144). In addition, each of the one or more conditional secondary cell configurations may be associated with at least one trigger condition stored in the trigger condition field 146.

[0387] Each of the one or more conditional secondary cell configurations included in the configuration message 138 (47) is configured to instruct the wireless terminal 26 to establish a second radio connection with a secondary access node when at least one trigger condition associated with each of the one or more conditional secondary cell configurations is satisfied, and the secondary access node serves the candidate primary secondary cell included in each of the one or more conditional secondary cell configurations.

[0388] Figure 49 To show that Figure 47 Flowchart of representative general steps or actions performed by the wireless terminal 26 of FIG. Action 49-1 comprises establishing a first radio connection with a primary access node (eg, with a primary gNodeB 22).

[0389] Action 49-2 includes receiving a reconfiguration message including one or more conditional secondary cell configurations. Each of the one or more conditional secondary cell configurations may include the identity of a candidate primary and secondary cell that can be used for dual connectivity (DC) (stored in the PSCell field 144). Each of the one or more conditional secondary cell configurations may be associated with at least one trigger condition stored in the trigger condition field 146. Each of the one or more conditional secondary cell configurations may be configured to instruct the wireless terminal to establish a second radio connection with a secondary access node, which serves the candidate primary and secondary cell included in each of the one or more conditional secondary cell configurations, if at least one trigger condition associated with each of the one or more conditional secondary cell configurations is satisfied. Therefore, action 49-3 includes the wireless terminal 26 establishing a second radio connection with a secondary access node, which serves the candidate primary and secondary cell included in the one of the one or more conditional secondary cell configurations, if at least one trigger condition associated with one of the one or more conditional secondary cell configurations is satisfied.

[0390] From the above content, we can understand that Figure 47 The configuration message 138 (47) of the embodiment and mode relates to the conditional configuration of one or more secondary cell groups (SCGs). Figure 37 The exemplary embodiments and modes of the previous embodiment of the present invention provide an understanding of exemplary cases of the generation of configuration message 138 (47) and examples of how configuration message 138 (47) may be constructed or encapsulated within other messages. For example, Figure 41 and Table 1 provide an exemplary scenario / procedure for adding a secondary node, while Figure 44 and Table 2 provide exemplary situations / procedures for modifying the current SCG configuration within the same SN.

[0391] Thus, one or more conditional secondary cell configurations may be included in an add / modify list, e.g., an add / mod list, wherein the add / modify list indicates whether each of the one or more conditional secondary cell configurations in the add / modify list is a new conditional secondary cell configuration or an updated configuration of a conditional secondary cell configuration stored in the wireless terminal. Additionally, identifiers of one or more conditional secondary cell configurations previously configured to the wireless terminal may be included in a release list, wherein the release list indicates that the conditional secondary cell configurations identified by the identifiers in the release list need to be released. Thus, the configuration message 138 (47) may be formatted in a manner that expresses a "list" of conditional secondary cell configurations, wherein the nature of the list (e.g., add / modify or release) is specified in the configuration message 138 (47) or by another message.

[0392] Listing 15 shows an exemplary format for a configuration of conditional PSCell addition / modification using multiple candidate PSCells, where the information element condPSCellAddModList includes a list of conditional PSCell configurations CondPSCellConfig, and the MN can use condPSCellReleaseList to instruct the UE to release some of these conditional PSCell configurations. The information element condPSCellConfigId can be used to identify a specific CondPSCellConfig. If the current UE configuration (i.e., the configuration for conditional PSCell addition / modification stored in the UE) includes a CondPSCellConfig with a given condPSCellConfigId in the condPSCellAddModList, the UE can modify the current UE configuration using the received CondPSCellConfig, otherwise the UE can add the received CondPSCellConfig to the current UE configuration. If the current UE configuration includes a CondPSCellConfig with a given condPSCellConfigId in the condPSCellReleaseList, the UE can release the CondPSCellConfig from the current UE configuration.

[0393]

[0394]

[0395] As mentioned above, in Figure 47 In one exemplary implementation of the embodiments and modes, each candidate PSCell configuration (e.g., each SCG configuration having a candidate PSCell) may be associated with one or more specified triggering conditions. Figure 47 The conditional secondary cell configuration memory 140 (147) is shown in which an unpopulated PSCell is associated with an unpopulated trigger event value in its associated trigger condition field 146, and a populated PSCell is associated with a populated trigger value in its associated trigger condition field 146. However, in Figure 47 In another exemplary implementation of the embodiments and modes, a trigger condition may be shared by all or some of the multiple candidate PSCells, for example, by being shared by populated and unpopulated PSCells.

[0396] It should be noted that CondPSCellConfig may include an SK counter (sk-Counter), see Figure 43For example, the counter may be associated with a candidate PSCell. The SK counter may be used when the master gNodeB 22 determines the value of the SK counter to distinguish between multiple candidate PSCells. In this case, the SK counter in the information element RRCReconfiguration-v1560-IE may be omitted or ignored.

[0397] 9: Add / modify PSCell configuration based on security configuration release conditions

[0398] Figure 37 、 Figure 44 and Figure 47 The exemplary embodiments and modes of the present invention disclose techniques in which security keys for a secondary node (SN) can be generated and used for a candidate PSCell. In those techniques, the currently active access stratum (AS) key K gNB Used as input to a key derivation function (KDF) to derive a secondary key (e.g., a key K SN ),like Figure 43 In actual use, the secondary key K SN In the currently active key K gN B may need to be updated if it is updated. As a result, the conditional PSCell adds / modifies the configuration, which always depends on the current key K. gNB Derived secondary key K SN , in K gNB It may become invalid during update.

[0399] The fifth part of this paper, "Release CHO configuration based on security configuration", discloses the K gNB The updated situation is as follows:

[0400] Re-establish after RLF

[0401] Inter-gNB handover

[0402] Instant key change

[0403] Intra-gNB handover

[0404] According to an exemplary aspect of the technology disclosed herein, if the current active access stratum (AS) key K gNB In any of the cases listed above, or any other case, the wireless terminal 26 may release the conditional PSCell add / modify configuration.

[0405] According to one exemplary implementation of this exemplary aspect, a master gNodeB 22 that has configured a conditional PSCell addition / modification may coordinate with one or more secondary nodes (SNs) to cancel the PSCell addition / modification configuration.

[0406] According to another exemplary implementation of this aspect, the wireless terminal 26 may suspend (e.g., deactivate) the conditional PSCell add / modify configuration. In this "suspend" implementation, the master gNodeB 22 may coordinate with one or more secondary nodes (SNs) to update the K SN At the same time, other configuration parameters are saved, and then the MN RRCRecon-figuration message with the new SK counter is sent to the wireless terminal 26 so that the wireless terminal 26 can derive the updated K SN and resume the conditional PSCell add / modify configuration. The wireless terminal 26 may maintain (e.g., not release) the suspended conditional PSCell add / modify configuration and may release the suspended conditional PSCell add / modify configuration when explicitly instructed by the master gNodeB 22 using a signaling message (e.g., RRCReconfiguration including the aforementioned release list) or when a timer expires. The timer may be pre-configured or configured by the master gNodeB 22. It should be noted that the suspension mode and operation for the PSCell add / modify configuration may also be applied to the release of the CHO configuration disclosed in Section 5. Therefore, after suspending (deactivating) the CHO configuration, the wireless terminal may maintain the CHO configuration until the source gNB explicitly instructs to release the CHO configuration or until a timer expires.

[0407] Figure 50 A system 20 (50) is shown in which one or more conditional secondary cell configurations are invalidated when the first master key changes. Figure 50 The system 20 (50) is shown as including a source gNodeB 22, a wireless terminal 26, and a plurality of secondary cell groups (SCGs). Figure 50 In the exemplary embodiment and mode of FIG. 2 , the source gNodeB 22 acts as a master node (MN) and may therefore also be referred to as a master gNodeB 22 . Figure 50 The master gNodeB 22 and its node processor 30 and the wireless terminal 26 and its terminal processor 40 are similar to Figure 6 、 Figure 11 、 Figure 15 、 Figure 19 、 Figure 28 、 Figure 37 、 Figure 44 and Figure 47 those of the present invention, wherein similar elements and functions have similar reference numerals. Figure 50As shown, the source gNodeB 22 includes a node processor circuit ("node processor 30") and a node transceiver circuit 32, wherein the node transceiver circuit 32 includes a node transmitter 34 and a node receiver 36. The node processor 30 includes a node frame / signal scheduler / handler 50; a message generator 54; an RRC state machine 56; a handover controller 60; and a security context manager 90 (50). As in the previous exemplary embodiments and modes, the handover controller 60 may include a measurement analyzer 62, a conditional handover (CHO) determination unit 64, and a conditional handover configuration information generator 66. Figure 50 In the embodiment and mode, the message generator 54 can also be referred to as a conditional configuration message generator 54 because it generates a configuration message for the wireless terminal 26 to belong to or have access to one or more cells in an SCG in the multi-secondary cell group (SCG), and the configuration message includes configuration information for conditional switching to the SCG.

[0408] When acting as a master node, the gNodeB 22 may control the connectivity of the wireless terminals it serves, including the wireless terminals 26. To this end, the node processor 30 of the gNodeB 22 is shown as including a master node connectivity controller 120. The master node connectivity controller 120 may execute an instance of connectivity control logic, a program, or a connectivity control routine for each wireless terminal 26 it serves. Figure 38 ), for each wireless terminal 26, an instance of the connectivity control program may include primary cell group connectivity logic 122 and secondary cell group connectivity control logic 124. Because certain aspects of the technology disclosed herein relate to secondary cell groups (SCGs), Figure 50 Also shown is the secondary cell group connectivity control logic 124, which may include or have access to network plan or network topology information 126. The network plan or network topology information 126 may include a database of nodes that may be eligible for inclusion in, or are actually included in, a secondary cell group (SCG) to which the wireless terminal 26 has access. The secondary cell group connectivity control logic 124 may also include conditional handover triggering logic 128. The conditional handover triggering logic 128 may include intelligence for generating conditions for handover to an SCG, e.g., triggering conditions for handover to one or more secondary cells included in a secondary cell group (SCG) for the wireless terminal 26. Such triggering conditions may be the same or different for different cells included in the plurality of secondary cell groups (SCGs).

[0409] The security context manager 90 (50) of the master gNodeB 22 comprises a first security context generator 91 and a second key generator 92 (50) that derives a second key for establishing a second security context and, therefore, derives one or more security keys for a radio connection with one or more secondary cells included in the conditional secondary cell configuration. Figure 50 As shown, the security context manager 90 (50) includes a first security context generator 91 and a second key generator 92 (50). The second key generator 92 (50) can be Figure 43 The second key for the secondary node is derived in a manner understood. Figure 50 In an exemplary embodiment and mode, the security context manager 90 (50) further includes a secondary cell group (SCG) configuration invalidator 180, such as an SCG invalidator 180. As used herein, "invalidation" encompasses both "cancellation" and "suspension" of a secondary cell group (SCG) configuration.

[0410] As in the previous exemplary embodiments and modes, Figure 50 The wireless terminal 26 of the exemplary embodiment and mode of the present invention includes a terminal processor 40 and a terminal transceiver circuit 42, wherein the terminal transceiver circuit 42 in turn includes a terminal transmitter 44 and a terminal receiver 46. The terminal processor 40 also includes a terminal frame / signal processing program 52, a message processor 70, a switching unit 72 and a measurement controller 80. Although in Figure 50 It is not specifically shown in FIG, but it should be understood that Figure 15 、 Figure 19 、 Figure 28 、 Figure 37 、 Figure 44 and Figure 47 In this way, the measurement controller 80 may further include a measurement initiation unit, a measurement result unit and a measurement report control unit. In addition, Figure 50 The terminal processor 40 is shown as including a terminal security context manager 94 (50).

[0411] The wireless terminal 26 includes a connection controller 130, which may be implemented or included in the terminal processor 40. Figure 50The wireless terminal 26 may be able to utilize dual connectivity operation, and thus the connection controller 130 is shown as including primary cell group connectivity logic 132 and secondary cell group connectivity control logic 134. As previously explained, each of the multiple secondary cell groups (SCGs) may include a PSCell and other cells, such as SCells. As an exemplary aspect of the technology disclosed herein, the primary gNodeB 22 may permit and / or authorize the wireless terminal 26 to perform a conditional handover to the SCG, and the conditional handover to the SCG may involve any one of the cells in the involved secondary cell groups (SCGs). Information related to the conditional handover to the SCG for each of the multiple secondary cell groups (SCGs) may be provided by the primary gNodeB 22 to the wireless terminal 26 in a configuration message 138 (50) generated by the message generator 54. The configuration message 138 (50) may also be referred to as a reconfiguration message 138 (50) or a conditional configuration message. The master gNodeB 22 provides a configuration message 138 (50) so that the secondary cell group connectivity control logic 134 can instruct the handover unit 72 to perform a conditional handover to the SCG when the condition specified in the configuration message 138 (50) occurs. This information may also be referred to herein as conditional configuration information. Configuration information for each SCG in the plurality of secondary cell groups (SCGs) and for each cell in each secondary cell group (SCG) may be stored in a conditional secondary cell configuration memory 140 (50) to which the secondary cell group connectivity control logic 134 has access. For one or more cells in the plurality of secondary cell groups (SCGs) to which the wireless terminal 26 belongs, the conditional secondary cell configuration memory 140 (50) includes Figure 44 The fields or records shown in , include a configuration identification field 142 ; a PSCell field 144 , a trigger condition field 146 , and an optional security key utilization counter field 148 . Figure 50 Specifically shown is a conditional secondary cell configuration memory 140 (50) including fields or records associated with unpopulated secondary cell groups (SCGs) and fields or records associated with populated secondary cell groups (SCGs), and thus accommodating storage of multiple secondary cell group (SCG) configurations.

[0412] The wireless terminal 26 also includes a terminal security context manager 94 (50). The terminal security context manager 94 (50) in turn includes a terminal first context generator 95; a terminal second key generator 96 (50); a key change detector 182; and a secondary cell group (SCG) configuration invalidator 184. The terminal second key generator 96 (50) derives one or more security keys for radio connections with one or more secondary cells included in the conditional secondary cell configuration. Figure 43 To understand the derivation of the second key for the secondary node SN, for example, the key K SNAs described herein, the key change detector 182 detects the current first master key (eg, K gNB ) changes and notifies the secondary cell group (SCG) configuration invalidator 184. The secondary cell group (SCG) configuration invalidator 184 then invalidates the secondary cell configuration memory 140 (50) with the changed master key K gNB Derived secondary key K SN One or more secondary cell groups (SCGs) are configured as "invalid".

[0413] Thus, the master gNodeB 22 includes a message generator 54 that can generate and transmit a configuration message 138 (50) to the wireless terminal 26, the configuration message including one or more SCG configurations with the PSCell configuration. The SCG configurations are preferably stored in the conditional secondary cell configuration memory 140 (50). The secondary cell group connectivity control logic 134 of the UE that receives the configuration message can begin synchronization with the configured PSCell and then establish a radio connection / bearer with the SCell in the SCG after the wireless terminal 26 determines that the trigger condition associated with the SCG configuration is satisfied.

[0414] Figure 51 To show that Figure 50 Flowchart of representative general steps or actions performed by a master gNodeB 22 of the wireless terminal. Action 51-1 includes establishing a first security context on a first radio connection with a wireless terminal using a first master key. Action 51-2 includes transmitting a reconfiguration message including one or more conditional secondary cell configurations and at least one counter to the wireless terminal 26. For example, the reconfiguration message can be a configuration message 138 (50). Each conditional secondary cell configuration can include an identity of a candidate primary and secondary cell and at least one trigger condition. The candidate secondary cell can be used for dual connectivity (DC). The at least one counter and the first master key are used to derive a second master key, which is used to establish a second security context with one of the candidate primary and secondary cells. Action 51-3 includes invalidating the one or more conditional secondary cell configurations when the first master key changes.

[0415] In the case where the failure of the configuration is a cancellation, action 51-3 may include the master gNodeB 22 coordinating with the secondary nodes, i.e., SNs, to cancel the PSCell add / modify configuration. In the case where the failure is a "pause" of the configuration, the master gNodeB 22 may coordinate with one or more secondary nodes (SNs) to update the K SN At the same time, other configuration parameters are saved, and then a MN RRCReconfiguration message with a new SK counter is sent to the wireless terminal 26 so that the wireless terminal 26 can derive the updated K SNAnd restore the conditional PSCell add / modify configuration.Deactivation of the clear condition or the suspend condition may be performed by the node processor 30 (eg, processor circuitry of the master gNodeB 22, such as the SCG disabler 180). Figure 50 An example of an SCG invalidator 180 coordinating with a secondary node SN is shown by arrow 186. The coordination between the primary gNodeB 22 and such a secondary node can be achieved by Figure 50 The appropriate interface is not explicitly shown.

[0416] Figure 52 To show that Figure 50 Flowchart of representative general steps or actions performed by a wireless terminal 26 of the present invention. Action 52-1 includes establishing a first security context on a first radio connection with a primary access node using a first master key. Action 52-2 includes receiving a reconfiguration message including one or more conditional secondary cell configurations and at least one counter. For example, the reconfiguration message can be a configuration message 138 (50). As understood herein, each conditional secondary cell configuration may include the identity of a candidate primary and secondary cell and at least one trigger condition, and the candidate primary and secondary cells may be used for dual connectivity (DC). The at least one counter and the first master key may be used to derive a second master key, which is used to establish a second security context with one of the candidate primary and secondary cells. Action 52-3 includes invalidating the one or more conditional secondary cell configurations when the first master key changes. Figure 50 The secondary cell group (SCG) configuration invalidator 184 invalidates the secondary cell group (SCG) in the conditional secondary cell configuration memory 140 ( 50 ), as shown by arrow 188 .

[0417] Thus, action 52-3 includes detecting a change in the first master key. As described above, the change in the first master key may occur in the following circumstances: during a connection re-establishment procedure for recovering the first radio connection from a radio link failure (RLF); upon or after a handover of the first radio connection; or upon receiving a message indicating a change in the first master key.

[0418] In the case where the failure is a "pause" of the configuration, the master gNodeB 22 may coordinate with one or more secondary nodes (SNs) to update K SN At the same time, other configuration parameters are saved, and then a MN RRCReconfiguration message with a new SK counter is sent to the wireless terminal 26 so that the wireless terminal 26 can derive the updated K SNThe wireless terminal 26 may release the suspended conditional PSCell add / modify configuration when explicitly instructed by the master gNodeB 22 using a signaling message (e.g., RRCReconfiguration) or when a timer expires. This timer may be pre-configured or configured by the master gNodeB 22.

[0419] Therefore, the technology disclosed herein proposes, for example, a method and apparatus for a UE to process measurement reports associated with a conditional handover configuration. Specifically:

[0420] The UE may suppress measurement reporting for cells configured as candidate target cells for conditional handover. This suppression may be configured by the gNB of the serving cell.

[0421] The UE may be configured to continue measurement reporting in a periodic manner for cells that are candidate target cells for conditional handover. The periodicity may be configured by the gNB of the serving cell.

[0422] The gNB may configure the UE with the leave conditions associated with the conditional handover configuration. If some of the leave conditions are met, the UE may discard the conditional handover configuration.

[0423] The conditional handover configuration may be associated with a second security configuration. The security configuration may be used to establish a security context after performing the conditional handover.

[0424] • The conditional handover configuration may be released upon a mobility event (such as handover and re-establishment) based on the second security configuration and the first security configuration configured for the mobility event.

[0425] • A configuration mechanism for conditional PSCell addition / modification is disclosed, including configuration for multiple candidate PSCells and secure configuration for PSCells.

[0426] If the master security key of the master node (MN) has been changed, the PSCell add / modify configuration may fail.

[0427] Certain units and functions of system 20 may be implemented by electronic machinery. For example, electronic machinery may refer to processor circuits described herein, such as node processor 30 and terminal processor 40. In addition, the term "processor circuit" is not limited to meaning one processor, but may include multiple processors, where multiple processors operate at one or more sites. In addition, as used herein, the term "server" is not limited to one server unit, but may cover multiple servers and / or other electronic devices, and may be located at one site or distributed to different sites. Based on these understandings, Figure 53An example of an electronic machine, such as a processor circuit, is shown, which includes one or more processors 190, a program instruction memory 192; other memory 194 (e.g., RAM, cache, etc.); input / output interfaces 196 and 197, a peripheral device interface 198; support circuits 199; and a bus 200 for communication between the aforementioned units. Processor 190 may include the processor circuits described herein, such as node processor 30 and terminal processor 40.

[0428] The memory or registers described herein may be depicted as memory 194 or any computer-readable medium, which may be one or more of readily available memory such as random access memory (RAM), read-only memory (ROM), floppy disk, hard disk, flash memory, or any other form of digital storage (local or remote), and preferably has non-volatile properties, and thus may include memory. Support circuits 199 are coupled to processor 190 to support the processor in a conventional manner. These circuits include caches, power supplies, clock circuits, input / output circuits and subsystems, etc.

[0429] Although the processes and methods of the disclosed embodiments may be discussed as being implemented as software routines, some of the method steps disclosed therein may be performed in hardware and by a processor running the software. Thus, the embodiments may be implemented in software executed on a computer system, in hardware such as an application specific integrated circuit or other type of hardware, or in a combination of software and hardware. The software routines of the disclosed embodiments can be executed on any computer operating system and can be executed using any CPU architecture.

[0430] The functions of the various elements, including functional blocks, including but not limited to those labeled or described as "computers," "processors," or "controllers," may be provided through the use of hardware such as circuit hardware and / or hardware capable of executing software in the form of programming instructions stored on a computer-readable medium. Therefore, such functions and illustrated functional blocks should be understood to be hardware-implemented and / or computer-implemented, and therefore machine-implemented.

[0431] In terms of hardware implementation, a functional block may include or encompass, but is not limited to, digital signal processor (DSP) hardware, a reduced instruction set processor, hardware (e.g., digital or analog) circuitry, including but not limited to one or more application specific integrated circuits [ASICs] and / or one or more field programmable gate arrays (FPGAs), and (where appropriate) a state machine capable of performing such functionality.

[0432] In terms of computer implementation, a computer is generally understood to include one or more processors or one or more controllers, and the terms computer, processor, and controller are used interchangeably herein. When provided by a computer or processor or controller, these functions may be provided by a single dedicated computer or processor or controller, by a single shared computer or processor or controller, or by multiple separate computers or processors or controllers (some of which may be shared or distributed). In addition, the use of the term "processor" or "controller" may also be interpreted to refer to other hardware capable of performing such functions and / or executing software, such as the exemplary hardware described above.

[0433] Nodes that communicate using the air interface also have appropriate radio communication circuitry. Furthermore, the technology disclosed herein may additionally be considered to be fully embodied within any form of computer-readable storage, such as a solid-state memory, a magnetic disk, or an optical disk containing an appropriate set of computer instructions that will cause a processor to perform the technology described herein.

[0434] In addition, each functional block or various features of the node processor 30 and the terminal processor 40 used in each of the above-mentioned embodiments can be implemented or executed by a circuit (typically an integrated circuit or multiple integrated circuits). The circuit designed to perform the functions described in this specification may include a general-purpose processor, a digital signal processor (DSP), a dedicated or general-purpose integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device or a discrete hardware component or a combination thereof. The general-purpose processor can be a microprocessor, or alternatively, the processor can be a conventional processor, a controller, a microcontroller or a state machine. The general-purpose processor or each of the above-mentioned circuits can be configured by a digital circuit, or can be configured by an analog circuit. In addition, when the technology of making an integrated circuit that replaces the current integrated circuit appears due to the progress of semiconductor technology, the integrated circuit produced by this technology can also be used.

[0435] The techniques of the various exemplary embodiments and modes described herein may be implemented individually or in combination with each other. For example, Figure 6 One or more features of the exemplary embodiments and modes of Figure 11 One or more features of the exemplary embodiments and modes of Figure 15 One or more features of the exemplary embodiments and modes of Figure 19 One or more features of the exemplary embodiments and modes of Figure 28 One or more features of the exemplary embodiments and modes of Figure 37 One or more features of the exemplary embodiments and modes of Figure 44 One or more features of the exemplary embodiments and modes of Figure 47One or more features of exemplary embodiments and modes and Figure 50 One or more features of the exemplary embodiments and modes may be combined for use with one or more of each other.

[0436] It should be understood that the techniques disclosed herein are intended to address issues centered around radio communications and are necessarily rooted in computer technology and overcome issues that arise specifically in radio communications. Furthermore, the techniques disclosed herein improve upon the basic functionality of providing configuration information for one or more secondary cell groups (SCGs) to wireless terminals in order to efficiently operate the network 20 and reduce congestion in such operations.

[0437] The technology disclosed herein encompasses one or more of the following non-limiting, non-exclusive exemplary embodiments and modes:

[0438] Exemplary embodiment 1: A wireless terminal comprising:

[0439] a processor circuit configured to establish a first radio connection with a primary access node;

[0440] a receiver circuit configured to receive a reconfiguration message including one or more conditional secondary cell configurations, each of the one or more conditional secondary cell configurations including an identity of a candidate primary and secondary cell, each of the one or more conditional secondary cell configurations being associated with at least one triggering condition, the candidate primary and secondary cell being for dual connectivity (DC);

[0441] in

[0442] Each of the one or more conditional secondary cell configurations instructs the wireless terminal to establish a second radio connection with a secondary access node when at least one trigger condition associated with each of the one or more conditional secondary cell configurations is met, and the secondary access node serves the candidate primary and secondary cells included in each of the one or more conditional secondary cell configurations.

[0443] Exemplary embodiment 2: A wireless terminal according to exemplary embodiment 1, wherein the processor circuit is further configured to: establish the second radio connection with the secondary access node when at least one trigger condition associated with each of the one or more conditional secondary cell configurations is met, and the secondary access node serves the candidate primary and secondary cells included in each of the one or more conditional secondary cell configurations.

[0444] Exemplary embodiment 3: A wireless terminal according to exemplary embodiment 1, wherein the one or more conditional secondary cell configurations are included in an addition / modification list, and the addition / modification list indicates whether each of the one or more conditional secondary cell configurations in the addition / modification list is a new conditional secondary cell configuration or an updated configuration of the conditional secondary cell configuration stored in the wireless terminal.

[0445] Example embodiment 4: The wireless terminal according to example embodiment 1, wherein the reconfiguration message further includes a release list, the release list indicating one or more conditional secondary cell configurations to be released.

[0446] Example embodiment 5: A wireless terminal according to example embodiment 1, wherein a conditional secondary cell configuration is associated with a specified counter, the counter being used to calculate one or more security keys for the radio connection with the secondary cell included in the conditional secondary cell configuration.

[0447] Example embodiment 6: A method for a wireless terminal, the method comprising establishing a first radio connection with a primary access node; receiving a reconfiguration message comprising one or more conditional secondary cell configurations, each of the one or more conditional secondary cell configurations comprising an identity of a candidate primary and secondary cell, each of the one or more conditional secondary cell configurations being associated with at least one triggering condition, the candidate primary and secondary cell being for dual connectivity (DC);

[0448] in:

[0449] Each of the one or more conditional secondary cell configurations instructs the wireless terminal to establish a second radio connection with a secondary access node when at least one trigger condition associated with each of the one or more conditional secondary cell configurations is met, and the secondary access node serves the candidate primary and secondary cells included in each of the one or more conditional secondary cell configurations.

[0450] Exemplary embodiment 7: The method according to exemplary embodiment 6 also includes using a processor circuit to establish the second radio connection with the secondary access node when at least one trigger condition associated with each of the one or more conditional secondary cell configurations is met, and the secondary access node serves the candidate primary and secondary cells included in each of the one or more conditional secondary cell configurations.

[0451] Exemplary embodiment 8: A method according to exemplary embodiment 6, wherein the one or more conditional secondary cell configurations are included in an add / modify list, and the add / modify list indicates whether each of the one or more conditional secondary cell configurations in the add / modify list is a new conditional secondary cell configuration or an updated configuration of the conditional secondary cell configuration stored in the wireless terminal.

[0452] Example embodiment 9: The method according to Example embodiment 6, wherein the reconfiguration message further includes a release list, the release list indicating one or more conditional secondary cell configurations to be released.

[0453] Example embodiment 10: A method according to example embodiment 6, wherein a conditional secondary cell configuration is associated with a designated counter, the counter being used to calculate one or more security keys for the radio connection with the secondary cell included in the conditional secondary cell configuration.

[0454] Example embodiment 11: An access node comprising:

[0455] a processor circuit configured to establish a first radio connection with a wireless terminal;

[0456] a transmitter circuit configured to transmit a reconfiguration message including one or more conditional secondary cell configurations, each of the one or more conditional secondary cell configurations including an identity of a candidate primary and secondary cell, each of the one or more conditional secondary cell configurations being associated with at least one triggering condition, the candidate primary and secondary cell being used for dual connectivity (DC);

[0457] in:

[0458] Each of the one or more conditional secondary cell configurations instructs the wireless terminal to establish a second radio connection with a secondary access node when at least one trigger condition associated with each of the one or more conditional secondary cell configurations is met, and the secondary access node serves the candidate primary and secondary cells included in each of the one or more conditional secondary cell configurations.

[0459] Example Embodiment 12: The access node of Example Embodiment 11, wherein the processor circuit is further configured to generate the reconfiguration message.

[0460] Exemplary embodiment 13: An access node according to exemplary embodiment 11, wherein the one or more conditional secondary cell configurations are included in an add / modify list, and the add / modify list indicates whether each of the one or more conditional secondary cell configurations in the add / modify list is a new conditional secondary cell configuration or an updated configuration of the conditional secondary cell configuration stored in the wireless terminal.

[0461] Example embodiment 14: The access node of example embodiment 11, wherein the reconfiguration message further includes a release list indicating one or more conditional secondary cell configurations to be released.

[0462] Example embodiment 15: An access node according to example embodiment 11, wherein a conditional secondary cell configuration is associated with a specified counter, the counter being used to calculate one or more security keys for the radio connection with the secondary cell included in the conditional secondary cell configuration.

[0463] Example embodiment 16: A method for an access node, the method comprising: establishing a first radio connection with a wireless terminal; transmitting a reconfiguration message comprising one or more conditional secondary cell configurations, each of the one or more conditional secondary cell configurations comprising an identity of a candidate primary and secondary cell, each of the one or more conditional secondary cell configurations being associated with at least one triggering condition, the candidate primary and secondary cell being for dual connectivity (DC);

[0464] in:

[0465] Each of the one or more conditional secondary cell configurations instructs the wireless terminal to establish a second radio connection with a secondary access node when at least one trigger condition associated with each of the one or more conditional secondary cell configurations is met, and the secondary access node serves the candidate primary and secondary cells included in each of the one or more conditional secondary cell configurations.

[0466] Example Embodiment 17: The method of Example Embodiment 16, further comprising generating the reconfiguration message using a processor circuit.

[0467] Exemplary embodiment 18: A method according to exemplary embodiment 16, wherein the one or more conditional secondary cell configurations are included in an add / modify list, and the add / modify list indicates whether each of the one or more conditional secondary cell configurations in the add / modify list is a new conditional secondary cell configuration or an updated configuration of the conditional secondary cell configuration stored in the wireless terminal.

[0468] Example embodiment 19: The method according to example embodiment 16, wherein the reconfiguration message further includes a release list, the release list indicating one or more conditional secondary cell configurations to be released.

[0469] Example embodiment 20: A method according to example embodiment 16, wherein a conditional secondary cell configuration is associated with a designated counter, the counter being used to calculate one or more security keys for the radio connection with the secondary cell included in the conditional secondary cell configuration.

[0470] Exemplary embodiment 21: A wireless terminal comprising:

[0471] a processor circuit configured to establish a first security context over a first radio connection with a primary access node using a first master key;

[0472] A receiver circuit, wherein the receiver circuit receives a reconfiguration message including one or more conditional secondary cell configurations and at least one counter, each conditional secondary cell configuration including an identity of a candidate primary and secondary cell and at least one trigger condition, the candidate primary and secondary cell being used for dual connectivity (DC), the at least one counter and the first master key being used to derive a second master key, and the second master key being used to establish a second security context with one of the candidate primary and secondary cells; wherein:

[0473] The one or more conditional secondary cell configurations become invalid when the first master key changes.

[0474] Example embodiment 22: The wireless terminal of Example embodiment 21, wherein the processor circuit is further configured to disable the one or more conditional secondary cell configurations when the first master key changes.

[0475] Example embodiment 23: The wireless terminal according to example embodiment 21, wherein the one or more conditional secondary cell configurations are released when the first master key changes.

[0476] Example embodiment 24: A wireless terminal according to example embodiment 21, wherein the one or more conditional secondary cell configurations are suspended when the first master key changes.

[0477] Example embodiment 25: A wireless terminal according to example embodiment 21, wherein the first master key is changed during a connection re-establishment procedure for recovering the first radio connection from a radio link failure (RLF).

[0478] Example embodiment 26: The wireless terminal of example embodiment 21, wherein the first master key is changed upon or after handover of the first radio connection.

[0479] Example embodiment 27: The wireless terminal according to example embodiment 21, wherein the first master key is changed when a message indicating that the first master key is changed is received.

[0480] Example embodiment 28: A method for a wireless terminal, comprising: establishing a first security context over a first radio connection with a primary access node using a first master key;

[0481] receiving a reconfiguration message including one or more conditional secondary cell configurations and at least one counter, each conditional secondary cell configuration including an identity of a candidate primary and secondary cell and at least one trigger condition, the candidate primary and secondary cell being used for dual connectivity (DC), the at least one counter and the first master key being used to derive a second master key, the second master key being used to establish a second security context with one of the candidate primary and secondary cells;

[0482] in:

[0483] The one or more conditional secondary cell configurations become invalid when the first master key changes.

[0484] Example embodiment 29: The method of Example embodiment 28 further comprising, using a processor circuit, invalidating the one or more conditional secondary cell configurations when the first master key changes.

[0485] Example embodiment 30: The method of example embodiment 28, wherein the one or more conditional secondary cell configurations are released when the first master key changes.

[0486] Example embodiment 31: The method of example embodiment 28, wherein the one or more conditional secondary cell configurations are suspended when the first master key changes.

[0487] Example embodiment 32: The method of example embodiment 28, wherein the first master key is changed during a connection re-establishment procedure for recovering the first radio connection from a radio link failure (RLF).

[0488] Example Embodiment 33: The method of Example Embodiment 28, wherein the first master key is changed upon or after handover of the first radio connection.

[0489] Example Embodiment 34: The method of Example Embodiment 28, wherein the first master key is changed upon receiving a message indicating a change in the first master key.

[0490] Example embodiment 35: An access node comprising:

[0491] a processor circuit configured to establish a first security context over a first radio connection with a wireless terminal using a first master key;

[0492] a transmitter circuit, the transmitter circuit transmitting a reconfiguration message including one or more conditional secondary cell configurations and at least one counter, each conditional secondary cell configuration including an identity of a candidate primary and secondary cell and at least one trigger condition, the candidate primary and secondary cell being used for dual connectivity (DC), the at least one counter and the first master key being used to derive a second master key, and the second master key being used to establish a second security context with one of the candidate primary and secondary cells;

[0493] in:

[0494] The one or more conditional secondary cell configurations become invalid when the first master key changes.

[0495] Example Embodiment 36: The access node of Example Embodiment 35, wherein the processor circuit is further configured to generate the reconfiguration message.

[0496] Example Embodiment 37: The access node of Example Embodiment 35, wherein the one or more conditional secondary cell configurations are released when the first master key changes.

[0497] Example embodiment 38: The access node of Example embodiment 37, wherein the processor circuit is further configured to coordinate the release of the one or more conditional secondary cell configurations with the primary candidate secondary cell.

[0498] Example Embodiment 39: The access node of Example Embodiment 35, wherein the one or more conditional secondary cell configurations are suspended when the first master key changes.

[0499] Example embodiment 40: The access node of example embodiment 39, wherein the processor circuit is further configured to coordinate the suspension of the one or more conditional secondary cell configurations with the primary candidate secondary cell.

[0500] Example Embodiment 41: The access node of Example Embodiment 35, wherein the first master key is changed during a connection re-establishment procedure for recovering the first radio connection from a radio link failure (RLF).

[0501] Example Embodiment 42: The access node of Example Embodiment 35, wherein the first master key is changed upon or after handover of the first radio connection.

[0502] Example Embodiment 43: The access node of Example Embodiment 35, wherein the first master key is changed upon or after transmitting a message to the wireless terminal indicating the change of the first master key.

[0503] Example embodiment 44: A method for accessing a node, comprising:

[0504] establishing a first security context over a first radio connection with a wireless terminal using the first master key;

[0505] transmitting a reconfiguration message including one or more conditional secondary cell configurations and at least one counter, each conditional secondary cell configuration including an identity of a candidate primary and secondary cell and at least one trigger condition, the candidate primary and secondary cell being used for dual connectivity (DC), the at least one counter and the first master key being used to derive a second master key, and the second master key being used to establish a second security context with one of the candidate primary and secondary cells;

[0506] in:

[0507] The one or more conditional secondary cell configurations become invalid when the first master key changes.

[0508] Example Embodiment 45: The method of Example Embodiment 44, further comprising generating the reconfiguration message using a processor circuit.

[0509] Example embodiment 46: The method of example embodiment 44, wherein the one or more conditional secondary cell configurations are released when the first master key changes.

[0510] Example embodiment 47: The method according to example embodiment 46 further includes coordinating the release of the one or more conditional secondary cell configurations with the primary candidate secondary cell.

[0511] Example embodiment 48: The method of example embodiment 44, wherein the one or more conditional secondary cell configurations are suspended when the first master key changes.

[0512] Example embodiment 49: The method according to example embodiment 48 further includes coordinating the suspension of the one or more conditional secondary cell configurations with the primary candidate secondary cell.

[0513] Example embodiment 50: The method of example embodiment 44, wherein the first master key is changed during a connection re-establishment procedure for recovering the first radio connection from a radio link failure (RLF).

[0514] Example Embodiment 51: The method of Example Embodiment 44, wherein the first master key is changed upon or after handover of the first radio connection.

[0515] Example embodiment 52: The method of example embodiment 24, wherein the first master key is changed upon or after transmitting a message indicating the change of the first master key to the wireless terminal.

[0516] Exemplary embodiment 53: A wireless terminal comprising:

[0517] a processor circuit configured to establish a first radio connection with a primary access node;

[0518] a receiver circuit configured to receive a reconfiguration message including one or more conditional secondary cell group (SCG) configurations, each of the one or more conditional SCG configurations including an identity of a candidate target primary cell (PSCell) for the SCG, each of the one or more SCG configurations being associated with at least one trigger condition, the candidate target PSCell being for dual connectivity (DC);

[0519] Each of the one or more conditional SCG configurations indicates that the wireless terminal establishes a second radio connection with a secondary access node when at least one trigger condition associated with each of the one or more conditional SCG configurations is met, and the secondary access node serves the candidate target PSCell included in each of the one or more conditional SCG configurations.

[0520] Exemplary embodiment 54: A wireless terminal according to exemplary embodiment 53, a wireless terminal according to claim 1, wherein the processor circuit is further configured to: establish the second radio connection with the secondary access node when the at least one trigger condition associated with one of the one or more conditional secondary cell configurations is met, and the secondary access node serves the candidate target PSCell included in the one of the one or more conditional SCG configurations.

[0521] Exemplary embodiment 55: A wireless terminal according to exemplary embodiment 53, wherein the one or more conditional SCG configurations are included in an addition / modification list, and the addition / modification list indicates whether each of the one or more conditional SCG configurations in the addition / modification list is a new conditional SCG configuration or a modified configuration of the conditional SCG configuration stored in the wireless terminal.

[0522] Example embodiment 56: A wireless terminal according to example embodiment 53, wherein the reconfiguration message also includes a release list, the release list indicating one or more conditional SCG configurations to be released.

[0523] Example embodiment 57: A wireless terminal according to example embodiment 53, wherein the conditional SCG configuration is associated with a counter, the counter being used to calculate one or more security keys for the second radio connection, the counter being specified for the conditional SCG configuration.

[0524] Example embodiment 58: A method for a wireless terminal, comprising:

[0525] establishing a first radio connection with a primary access node;

[0526] receiving a reconfiguration message including one or more conditional secondary cell group (SCG) configurations, each of the one or more conditional SCG configurations including an identity of a candidate target primary cell (PSCell) for the SCG, each of the one or more conditional SCG configurations being associated with at least one trigger condition, the candidate target PSCell being for dual connectivity (DC);

[0527] Each of the one or more conditional SCG configurations indicates that the wireless terminal establishes a second radio connection with a secondary access node when at least one trigger condition associated with each of the one or more conditional SCG configurations is met, and the secondary access node serves the candidate target PSCell included in each of the one or more conditional SCG configurations.

[0528] Exemplary embodiment 59: The method according to exemplary embodiment 58 also includes using a processor circuit to establish the second radio connection with the auxiliary access node when at least one trigger condition associated with one of the one or more conditional SCG configurations is met, and the auxiliary access node serves the candidate target PSCell included in the one of the one or more conditional SCG configurations.

[0529] Exemplary embodiment 60: A method according to exemplary embodiment 58, wherein the one or more conditional SCG configurations are included in an add / modify list, and the add / modify list indicates whether each of the one or more conditional SCG configurations in the add / modify list is a new conditional SCG configuration or a modified configuration of the conditional SCG configuration stored in the wireless terminal.

[0530] Example embodiment 61: The method of example embodiment 58, wherein the reconfiguration message further includes a release list indicating one or more conditional SCG configurations to be released.

[0531] Example embodiment 62: The method of example embodiment 58, wherein the conditional SCG configuration is associated with a counter for calculating one or more security keys for the second radio connection, the counter being specified for the conditional SCG configuration.

[0532] Example embodiment 63: An access node comprising:

[0533] a processor circuit configured to establish a first radio connection with a wireless terminal;

[0534] a transmitter circuit configured to transmit a reconfiguration message comprising one or more conditional secondary cell group (SCG) configurations, each of the one or more conditional SCG configurations comprising an identity of a candidate target primary cell (PSCell) for the SCG, each of the one or more conditional SCG configurations being associated with at least one trigger condition, the candidate target PSCell being for dual connectivity (DC);

[0535] Each of the one or more conditional SCG configurations indicates that the wireless terminal establishes a second radio connection with a secondary access node when at least one trigger condition associated with each of the one or more conditional SCG configurations is met, and the secondary access node serves the candidate target PSCell included in each of the one or more conditional SCG configurations.

[0536] Example Embodiment 64: The access node of Example Embodiment 63, wherein the processor circuit is further configured to generate the reconfiguration message.

[0537] Exemplary embodiment 65: An access node according to exemplary embodiment 63, wherein the one or more conditional SCG configurations are included in an add / modify list, and the add / modify list indicates whether each of the one or more conditional SCG configurations in the add / modify list is a new conditional SCG configuration or a modified configuration of the conditional SCG configuration stored in the wireless terminal.

[0538] Example Embodiment 66: The access node of Example Embodiment 63, wherein the reconfiguration message further includes a release list indicating one or more conditional SCG configurations to be released.

[0539] Example embodiment 67: The access node of example embodiment 63, wherein the conditional SCG configuration is associated with a counter for calculating one or more security keys for the second radio connection, the counter being specified for the conditional SCG configuration.

[0540] Example embodiment 68: A method for accessing a node, comprising:

[0541] establishing a first radio connection with a wireless terminal;

[0542] transmitting a reconfiguration message including one or more conditional secondary cell group (SCG) configurations, each of the one or more conditional SCG configurations including an identity of a candidate target primary cell (PSCell) for the SCG, each of the one or more conditional SCG configurations being associated with at least one triggering condition, the candidate target PSCell being for dual connectivity (DC);

[0543] Each of the one or more conditional SCG configurations indicates that the wireless terminal establishes a second radio connection with a secondary access node when at least one trigger condition associated with each of the one or more conditional SCG configurations is met, and the secondary access node serves the candidate target PSCell included in each of the one or more conditional SCG configurations.

[0544] Example Embodiment 69: The access node of Example Embodiment 68 further comprising using a processor circuit to generate the reconfiguration message.

[0545] Exemplary embodiment 70: An access node according to exemplary embodiment 68, wherein the one or more conditional SCG configurations are included in an add / modify list, and the add / modify list indicates whether each of the one or more conditional SCG configurations in the add / modify list is a new conditional SCG configuration or a modified configuration of the conditional SCG configuration stored in the wireless terminal.

[0546] Example embodiment 71: The access node of example embodiment 68, wherein the reconfiguration message further includes a release list indicating one or more conditional secondary cell configurations to be released.

[0547] Example embodiment 72: The access node of example embodiment 68, wherein the conditional secondary cell configuration is associated with a counter for calculating one or more security keys for the second radio connection, the counter being specified for the conditional SCG configuration.

[0548] Example embodiment 73: A wireless terminal comprising:

[0549] a processor circuit configured to establish a first security context over a first radio connection with a primary access node using a first access stratum (AS) master key;

[0550] a receiver circuit configured to receive a reconfiguration message comprising one or more conditional secondary cell group (SCG) configurations and at least one counter, each conditional SCG configuration comprising an identity of a candidate target primary cell (PSCell) for the SCG and at least one trigger condition, the candidate target PSCell being used for dual connectivity (DC), the at least one counter and a first AS master key being used to derive a second AS master key, the second AS master key being used to establish a second security context with the candidate target PSCell included in one of the one or more conditional SCG configurations; and the processor circuit being further configured to store the one or more conditional SCG configurations, wherein:

[0551] The stored one or more conditional secondary cell configurations are released when the first AS master key changes.

[0552] Example embodiment 74: A wireless terminal according to example embodiment 73, wherein the processor circuit is further configured to release the stored one or more conditional SCG configurations when the first AS master key changes.

[0553] Example embodiment 75: A wireless terminal according to example embodiment 73, wherein the first AS master key is changed during a connection re-establishment procedure for recovering the first radio connection from a radio link failure (RLF).

[0554] Example embodiment 76: A wireless terminal according to example embodiment 73, wherein the first AS master key is changed upon or after handover of the first radio connection.

[0555] Example embodiment 77: A wireless terminal according to example embodiment 73, wherein the first AS master key is changed when a message indicating that the first AS master key is changed is received.

[0556] Example embodiment 78: A method for a wireless terminal, comprising:

[0557] establishing a first security context over a first radio connection with a primary access node using a first access stratum (AS) master key;

[0558] receiving a reconfiguration message including one or more conditional secondary cell group (SCG) configurations and at least one counter, each conditional SCG configuration including an identity of a candidate target primary cell (PSCell) of the SCG and at least one trigger condition, the candidate target PSCell being used for dual connectivity (DC), the at least one counter and the first AS master key being used to derive a second AS master key, the second AS master key being used to establish a second security context with a candidate target PSCell included in one of the one or more conditional SCG configurations; and

[0559] The one or more conditional SCG configurations are stored, wherein:

[0560] The stored one or more conditional SCG configurations are released when the first AS master key changes.

[0561] Example embodiment 79: The method of example embodiment 78 further comprising releasing, using the processor circuit, the stored one or more conditional SCG configurations when the first AS master key changes.

[0562] Example embodiment 80: The method of example embodiment 78, wherein the first AS master key is changed during a connection re-establishment procedure for recovering the first radio connection from a radio link failure (RLF).

[0563] Example Embodiment 81: The method of Example Embodiment 78, wherein the first AS master key is changed upon or after handover of the first radio connection.

[0564] Example embodiment 82: The method of example embodiment 78, wherein the first master key is changed upon receiving a message indicating a change in the first AS master key.

[0565] Example embodiment 83: An access node comprising:

[0566] a processor circuit configured to establish a first security context over a first radio connection with a wireless terminal using a first access stratum (AS) master key;

[0567] a transmitter circuit configured to transmit a reconfiguration message, the reconfiguration message comprising one or more conditional secondary cell group (SCG) configurations and at least one counter, each conditional SCG configuration comprising an identity of a candidate target primary cell (PSCell) of the SCG and at least one trigger condition, the candidate target PSCell being used for dual connectivity (DC), the at least one counter and the first AS master key being used to derive a second AS master key, the second AS master key being used to establish a second security context with the candidate target PSCell included in one of the one or more conditional SCG configurations;

[0568] in:

[0569] The one or more conditional SCG configurations are released when the first master key changes.

[0570] Example Embodiment 84: The access node of Example Embodiment 83, wherein the processor circuit is further configured to generate the reconfiguration message.

[0571] Example Embodiment 85: The access node of Example Embodiment 83, wherein the first AS master key is changed during a connection re-establishment procedure for recovering the first radio connection from a radio link failure (RLF).

[0572] Example Embodiment 86: The access node of Example Embodiment 83, wherein the first AS master key is changed upon or after handover of the first radio connection.

[0573] Example Embodiment 87: The access node of Example Embodiment 83, wherein the first AS master key changes upon or after transmitting a message to the wireless terminal indicating the change of the first AS master key.

[0574] Example embodiment 88: A method for accessing a node, comprising:

[0575] establishing a first security context over a first radio connection with a wireless terminal using a first access stratum (AS) master key;

[0576] transmitting a reconfiguration message, the reconfiguration message including one or more conditional secondary cell group (SCG) configurations and at least one counter, each conditional SCG configuration including an identity of a candidate target primary cell (PSCell) for the SCG and at least one trigger condition, the candidate target PSCell being used for dual connectivity (DC), the at least one counter and the first master key being used to derive a second AS master key, the second AS master key being used to establish a second security context with the candidate target PSCell included in one of the one or more conditional SCG configurations;

[0577] in:

[0578] The one or more conditional SCG configurations are released when the first AS master key changes.

[0579] Example Embodiment 89: The method of Example Embodiment 88 further comprising generating the reconfiguration message using a processor circuit.

[0580] Example embodiment 90: The method of example embodiment 88, wherein the first AS master key is changed during a connection re-establishment procedure for recovering the first radio connection from a radio link failure (RLF).

[0581] Example Embodiment 91: The method of Example Embodiment 88, wherein the first AS master key is changed upon or after handover of the first radio connection.

[0582] Example embodiment 92: A method according to example embodiment 88, wherein the first AS master key is changed when or after a message indicating the change of the first AS master key is transmitted to the wireless terminal.

[0583] One or more of the following documents may be relevant to the technology disclosed herein (all of which are incorporated herein by reference in their entirety):

[0584] 3GPP RAN2#107 document:

[0585]

[0586]

[0587]

[0588] Although the above description contains many specific instructions, these should not be interpreted as limiting the scope of the technology disclosed herein, but only as providing illustrations of some currently preferred embodiments of the technology disclosed herein. Therefore, the scope of the technology disclosed herein should be determined by the appended claims and their legal equivalents. Therefore, it should be understood that the scope of the technology disclosed herein fully encompasses other embodiments that may become obvious to those skilled in the art, and therefore the scope of the technology disclosed herein is limited only by the appended claims, where a reference to an element in the singular does not mean "only one" (unless explicitly stated as such), but rather "one or more". The above embodiments may be combined with each other. All structural, chemical and functional equivalents of the elements of the above preferred embodiments known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the present claims. In addition, a device or method does not necessarily solve every problem that the technology disclosed herein seeks to solve, as it will be covered by the present claims. In addition, no element, component or method step of the present disclosure is intended to be dedicated to the public, regardless of whether the element, component or method step is explicitly stated in the claims.

[0589] <Summary of the invention>

[0590] In one of its exemplary aspects, the technology disclosed herein relates to the structure and operation of a wireless terminal that receives one or more secondary cell group (SCG) configurations from an access node. In an exemplary embodiment and mode, the wireless terminal includes a processor circuit and a receiver circuit. The processor circuit is configured to establish a first radio connection with a primary access node. The receiver circuit is configured to receive a reconfiguration message including one or more conditional secondary cell configurations. Each of the one or more conditional secondary cell configurations includes the identity of a candidate primary and secondary cell, and each of the one or more conditional secondary cell configurations is associated with at least one trigger condition, and the candidate primary and secondary cell is used for dual connectivity (DC). The processor circuit is further configured to establish a second radio connection with a secondary access node based on the one or more conditional secondary cell configurations, when at least one trigger condition associated with each of the one or more conditional secondary cell configurations is satisfied, and the secondary access node serves the candidate primary and secondary cell included in each of the one or more conditional secondary cell configurations. A method for operating such a wireless terminal is also provided.

[0591] In one of its exemplary aspects, the technology disclosed herein relates to the structure and operation of an access node that provides one or more secondary cell group (SCG) configurations to a wireless terminal. The processor circuit is configured to establish a first radio connection with a wireless terminal. The transmitter circuit is configured to transmit a reconfiguration message including one or more conditional secondary cell configurations. Each of the one or more conditional secondary cell configurations includes the identity of a candidate primary and secondary cell, and each of the one or more conditional secondary cell configurations is associated with at least one trigger condition, and the candidate primary and secondary cell is used for dual connectivity (DC). Each of the one or more conditional secondary cell configurations is configured to instruct the wireless terminal to establish a second radio connection with a secondary access node when at least one trigger condition associated with each of the one or more conditional secondary cell configurations is satisfied, and the secondary access node serves the candidate primary and secondary cell included in each of the one or more conditional secondary cell configurations. A method for operating such an access node is also provided.

[0592] In one of its exemplary aspects, the technology disclosed herein relates to the structure and operation of a wireless terminal, wherein a secondary cell group (SCG) configuration is invalidated when a master key changes. In an exemplary embodiment and mode, the wireless terminal includes a processor circuit and a receiver circuit. The processor circuit is configured to establish a first security context on a first radio connection with a primary access node using a first master key. The receiver circuit is configured as the receiver circuit is configured to receive a reconfiguration message including one or more conditional secondary cell configurations and at least one counter. Each conditional secondary cell configuration may include the identity of a candidate primary and secondary cell and at least one trigger condition, the candidate primary and secondary cell being used for dual connectivity (DC). The at least one counter and the first master key can be used to derive a second master key, which is used to establish a second security context with one of the candidate primary and secondary cells. The processor circuit is further configured to invalidate one or more conditional secondary cell configurations when the first master key changes. A method for operating such a wireless terminal is also provided.

[0593] In one of its exemplary aspects, the technology disclosed herein relates to the structure and operation of an access node for a dual-connection system, wherein a secondary cell group (SCG) configuration is invalidated when a master key changes. In an exemplary embodiment and mode, the access node includes a processor circuit and a receiver circuit. The processor circuit is configured to establish a first security context on a first radio connection with a wireless terminal using a first master key. The transmitter circuit is configured to transmit a reconfiguration message including one or more conditional secondary cell configurations and at least one counter to the wireless terminal. Each conditional secondary cell configuration may include the identity of a candidate primary and secondary cell and at least one trigger condition, the candidate primary and secondary cell being used for dual connection (DC). The at least one counter and the first master key can be used to derive a second master key, which is used to establish a second security context with one of the candidate primary and secondary cells. The wireless terminal is configured to invalidate one or more conditional secondary cell configurations when the first master key changes. A method for operating such an access node is also provided.

[0594] <Cross Reference>

[0595] This nonprovisional patent application claims priority under 35 U.S.C. §119 to provisional patent application 62 / 910,267, filed on October 3, 2019, the entire contents of which are hereby incorporated by reference.

Claims

1. A wireless terminal, comprising: a processor circuit configured to establish a first security context over a first radio connection with a primary access node using a first access stratum AS master key; a receiver circuit configured to receive a reconfiguration message, the reconfiguration message including one or more primary cell (PSCell) configurations of a conditional secondary cell group and at least one counter, each conditional PSCell configuration including an identity of a candidate PSCell and at least one specified trigger condition, the at least one counter and the first AS master key being used to derive a second AS master key, the second AS master key being used to establish a second security context with a candidate PSCell included in one of the one or more conditional PSCell configurations; and The processor circuit is further configured to store the one or more conditional PSCell configurations, wherein: The stored one or more conditional PSCell configurations are released when the first AS master key changes, wherein: Each of the one or more conditional PSCell configurations instructs the wireless terminal to establish a second radio connection with a secondary access node serving the candidate PSCell included in each of the one or more conditional PSCell configurations if at least one specified trigger condition associated with each of the one or more conditional PSCell configurations is met.

2. The wireless terminal according to claim 1, wherein The processor circuit is further configured to release the stored one or more conditional PSCell configurations when the first AS master key changes.

3. The wireless terminal according to claim 1, wherein The first AS master key is changed during a connection re-establishment procedure for recovering the first radio connection from a radio link failure (RLF).

4. The wireless terminal according to claim 1, wherein The first AS master key is changed during or after a handover of the first radio connection.

5. The wireless terminal according to claim 1, wherein Upon receiving a message indicating that the first AS master key is changed, the first AS master key is changed.

6. A method for a wireless terminal, the method comprising: establishing a first security context over a first radio connection with a primary access node using the first access stratum AS master key; receiving a reconfiguration message, the reconfiguration message including primary cell (PSCell) configurations of one or more conditional secondary cell groups and at least one counter, each conditional PSCell configuration including an identity of a candidate PSCell and at least one specified trigger condition, the at least one counter and the first AS master key being used to derive a second AS master key, the second AS master key being used to establish a second security context with a candidate PSCell included in one of the one or more conditional PSCell configurations; as well as The one or more conditional PSCell configurations are stored, wherein: The stored one or more conditional PSCell configurations are released when the first AS master key changes, wherein: Each of the one or more conditional PSCell configurations instructs the wireless terminal to establish a second radio connection with a secondary access node serving the candidate PSCell included in each of the one or more conditional PSCell configurations if at least one specified trigger condition associated with each of the one or more conditional PSCell configurations is met.

7. An access node, comprising: a processor circuit configured to establish a first security context over a first radio connection with a wireless terminal using a first access stratum AS master key; a transmitter circuit configured to transmit a reconfiguration message, the reconfiguration message including primary cell (PSCell) configurations of one or more conditional secondary cell groups and at least one counter, each conditional PSCell configuration including an identity of a candidate PSCell and at least one specified trigger condition, the at least one counter and the first AS master key being used to derive a second AS master key, the second AS master key being used to establish a second security context with a candidate PSCell included in one of the one or more conditional PSCell configurations; The one or more conditional PSCell configurations are released when the first AS master key changes, wherein: Each of the one or more conditional PSCell configurations instructs the wireless terminal to establish a second radio connection with a secondary access node serving the candidate PSCell included in each of the one or more conditional PSCell configurations if at least one specified trigger condition associated with each of the one or more conditional PSCell configurations is met.

8. The access node according to claim 7, wherein The processor circuit is further configured to generate the reconfiguration message.

9. The access node according to claim 7, wherein The first AS master key is changed during a connection re-establishment procedure for recovering the first radio connection from a radio link failure (RLF).

10. The access node according to claim 7, wherein The first AS master key is changed upon or after handover of the first radio connection.

11. The access node according to claim 7, wherein The first AS master key is changed upon or after transmitting a message indicating the change of the first AS master key to the wireless terminal.

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