Method, device and medium for operating in multi-radio dual connectivity MR-DC mode

Abstract

The present disclosure relates to ultra-reliable reporting of SCG measurements upon SpCell degradation. Disclosed herein are systems and methods for ultra-reliable reporting of secondary cell group (SCG) measurements to a secondary node (SN) used in multi-radio dual connectivity (MR-DC) operation, particularly taking into account the possibility of SCG special cell (SpCell) degradation. A user equipment (UE) may establish a signaling radio bearer (SRB) 3 with the SN. The UE may then identify that a handover condition for the SCG-SpCell is met (the handover condition may be associated with SCG-SpCell degradation), and accordingly send SCG measurement reports between the UE and a master node (MN) used in the MR-DC operation via each of the SRB3 and SRB1. Such information received at the MN is forwarded to the SN. Thus, receiving SCG measurement reports (to enable the SN to switch to a new SpCell) does not rely solely on messages on the SpCell of the SCG (using SRB3), thereby improving reliability.

Description

Technical Field

[0001] The present application generally relates to wireless communication systems, including systems and methods for ultra-reliable reporting of secondary cell group (SCG) measurements when using multi-radio dual connectivity (MR-DC). Background Art

[0002] Wireless mobile communication technology uses various standards and protocols to transmit data between base stations and wireless mobile devices. Wireless communication system standards and protocols may include the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) (e.g., 4G) or New Radio (NR) (e.g., 5G); the Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard, which is commonly referred to by industry organizations as Worldwide Interoperability for Microwave Access (WiMAX); and the IEEE 802.11 standard for Wireless Local Area Networks (WLANs), which is commonly referred to by industry organizations as Wi-Fi. In the 3GPP Radio Access Network (RAN) in an LTE system, a base station may include a RAN node such as an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node B (also commonly referred to as an evolved Node B, enhanced Node B, eNodeB, or eNB) and / or a Radio Network Controller (RNC) in the E-UTRAN, which communicates with a wireless communication device referred to as a user equipment (UE). In the present disclosure, a RAN node of an LTE system may sometimes be referred to as an LTE node. In the fifth generation (5G) wireless RAN, the RAN nodes may include 5G nodes, NR nodes (also known as next generation Node B or g NodeB (gNB)).

[0003] The RAN uses radio access technologies (RATs) to communicate between RAN nodes and UEs. The RAN may include Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE) RAN (GERAN), Universal Terrestrial Radio Access Network (UTRAN), and / or E-UTRAN, which provide access to communication services through the core network. Each RAN in the RAN operates according to a specific 3GPP RAT. For example, GERAN implements GSM and / or EDGE RATs, UTRAN implements Universal Mobile Telecommunications System (UMTS) RATs or other 3GPP RATs, E-UTRAN implements LTE RATs, and NG-RAN implements 5G RATs. In some deployments, E-UTRAN may also implement 5G RATs. Summary of the Invention

[0004] One aspect of the present disclosure relates to a method for a user equipment UE to operate in a multi-radio dual connectivity MR-DC mode with a master node MN and a secondary node SN, the method comprising: before a radio link failure RLF of a special cell SpCell of a secondary cell group SCG of the SN, a switching condition identifying the degradation of the SpCell of the SCG corresponding to the SN is detected at the UE; and in response to the switching condition identifying the degradation of the SpCell being detected at the UE: sending an SCG measurement report to the SN on a first signaling radio bearer SRB; and sending the SCG measurement report to the MN on a second SRB.

[0005] Another aspect of the present disclosure relates to a device for wireless communication, comprising: one or more processors; and a memory storing instructions that, when executed by the one or more processors, cause the method according to the present disclosure to be performed.

[0006] Yet another aspect of the present disclosure relates to a computer-readable medium having a computer program stored thereon, which, when executed by one or more processors, causes an apparatus to perform the steps of the method according to the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] To easily identify the discussion of any particular element or act, the most significant digit(s) in a reference number refers to the drawing number that first introduces the element.

[0008] Figure 1 An EN-DC architecture according to embodiments herein is shown.

[0009] Figure 2 The NR-DC architecture according to the implementation scheme of this article is shown.

[0010] Figure 3 A flowchart is shown in which the SCG measurement report from the UE fails to reach the SN on SRB3 due to SCG SpCell degradation when the UE operates in NR-DC mode according to an embodiment.

[0011] Figure 4 A flow chart is shown in which an SCG measurement report from a UE fails to reach the SN on SRB3 due to SCG SpCell degradation when the UE operates in EN-DC mode according to an embodiment.

[0012] Figure 5 A flowchart is shown in which the SCG measurement report from the UE fails to reach the SN on SRB3 due to SCG SpCell degradation when the UE operates in NR-DC mode according to an embodiment.

[0013] Figure 6 A flow chart is shown in which an SCG measurement report from a UE fails to reach the SN on SRB3 due to SCG SpCell degradation when the UE operates in EN-DC mode according to an embodiment.

[0014] Figure 7 A flow chart of a system using NR-DC according to an embodiment is shown, which NR-DC is configured to send SCG measurement reports to both the MN and the SN in response to a handover condition associated with the SN and when SRB3 is configured between the UE and the SN.

[0015] Figure 8 A flow chart of a system using EN-DC configured to send SCG measurement reports to both the MN and the SN in response to a handover condition associated with the SN and when SRB3 is configured between the UE and the SN is shown according to an embodiment.

[0016] Figure 9 A flow chart of a system using NR-DC according to an embodiment is shown, which is configured to send SCG measurement reports to both the MN and the SN in response to a handover condition associated with the SN and when SRB3 is configured between the UE and the SN.

[0017] Figure 10 A flow chart of a system using EN-DC according to an embodiment is shown, which is configured to send SCG measurement reports to both the MN and the SN in response to handover conditions associated with the SN and when SRB3 is configured between the UE and the SN.

[0018] Figure 11 A method of a UE operating in MR-DC mode with a MN and a SN according to an embodiment is shown.

[0019] Figure 12 A method in which the SN and the UE can operate using the MR-DC mode with the MN and the SN according to an embodiment is shown.

[0020] Figure 13 A UE according to one embodiment is shown.

[0021] Figure 14 A network node according to one embodiment is shown.

[0022] Figure 15 Components according to one embodiment are shown. DETAILED DESCRIPTION

[0023] Multi-Radio Dual Connectivity (MR-DC) is a generalization of Dual Connectivity (DC) within E-UTRA, where a UE with multiple (Rx) / (Tx) capabilities can be configured to utilize resources provided by two different nodes, one node providing NR access and the other providing E-UTRA (LTE) or NR access. One node can act as a master node (MN) and the other node can act as a secondary node (SN). The MN and SN can be connected via a network interface, and at least the MN is connected to the core network. The MN and / or SN can operate using shared spectrum channel access.

[0024] The UE can access the network using one network node or using two different nodes with various MR-DC modes. Examples of possible MR-DC modes include E-UTRA-NR dual connectivity (EN-DC) mode and NR-NR dual connectivity (NR-DC) mode. In these MR-DC modes, the UE can communicate with the MN using one or more cells of the primary cell group (MCG) available / provided by the MN, and the UE can communicate with the SR using one or more cells of the secondary cell group (SCG) provided by the SN. Each of the MCG and SCG respectively uses one or more cells including at least a corresponding special cell (SpCell) to communicate with the UE, where the SpCell of the MCG is sometimes referred to as a PCell, and the SpCell of the SCG is sometimes referred to as a PSCell.

[0025] Figure 1 FIG. 1 shows an EN-DC architecture 100 according to an embodiment of the present invention. The EN-DC architecture 100 includes an E-UTRAN 102 and an EPC 104. The E-UTRAN 102 supports MR-DC via EN-DC, wherein the UE (in Figure 1 In the example, UE 106 is connected to an eNB that acts as a MN (in Figure 1 In the example, eNB 108) and an en-gNB acting as a SN (in the example Figure 1 In the example, en-gNB 112 may be a node that provides NR user plane and control plane protocol termination to UE 106 and may act as a SN in EN-DC. Figure 11. In the embodiment of the present invention, EPC 104 may include one or more mobility management entities / serving gateways (MME / S-GW), such as MME / S-GW 118 and MME / S-GW 116. By way of example, E-UTRAN 102 may include eNB 108, eNB 110, en-gNB 112, and en-gNB 114. Each of eNB 108 and eNB 110 may be connected to EPC 104 via one or more S1 interfaces 120 and to one or more en-gNBs via one or more X2 interfaces 124. Each of en-gNB 112 and en-gNB 114 may be connected to EPC 104 via one or more S1-U interfaces 122. en-gNB 112 and en-gNB 114 may be connected to each other via an X2-U interface 126.

[0026] Figure 2 2 shows an NR-DC architecture 200 according to an embodiment of the present invention. By way of example, Figure 2 The NR-DC architecture 200 shows a UE 202, a gNB (MN) 204, a gNB (SN) 206, and a 5G core network (5GC) 208. In NR-DC, the UE 202 is connected to a first gNB (MN) 204 acting as a MN and a second gNB (SN) 206 acting as a SN. The gNB (MN) 204 is connected to the 5GC 208 via an NG interface 210 and to the gNB (SN) 206 via an Xn interface 212. In addition, in some embodiments, the gNB (SN) 206 can be connected to the 5GC 208 via an NG-U interface 214.

[0027] Signaling data associated with the use of MR-DC can be carried from the UE to either the mobile network (MN) or the network service provider (SN) using one or more signaling radio bearers (SRBs). The SRBs can be used to establish a radio access bearer (RAB) during connection establishment and can then be used to deliver signaling when the UE connects to the connection. This signaling can be related to the management of the connection. For example, the SRBs can be used to perform handovers, perform and / or report measurements, handle reconfiguration or releases, and more.

[0028] SRB1 can be configured for use between a UE and a MN. SRB1 can be used for Radio Resource Control (RRC) messages (including backpack Non-Access Stratum (NAS) messages) and NAS messages before establishing SRB2. This signaling can occur using a dedicated control channel (DCCH).

[0029] SRB2 can be configured for use between the UE and the MN. SRB2 can be used for RRC messages that include logged measurement information. This signaling can occur using the DCCH. Note that SRB2 has a lower priority than SRB1 and can be configured by the network after access stratum (AS) security activation has occurred.

[0030] SRB3 can be configured for use between the UE and the SN. When the UE is in EN-DC or NR-DC mode, SRB3 can be used for specific RRC messages and DCCH can be used. In the cases involving EN-DC and NR-DC to be discussed in this article, SRB3 can be used for example for measurement configuration and reporting; UE-assisted (re)configuration and reporting for power saving; constants for (re)configuration of medium access control (MAC), radio link control (RLC), physical layer and radio link failure (RLF) timers and SCG configuration; for reconfiguration of SN key (SK gNB ) or SRB3 associated with the Data Radio Bearer (DRB); used to reconfigure the SK gNB The Service Data Adaptation Protocol (SDAP) for the associated DRB; and the conditional SpCell for adding / modifying / issuing SCG (PSCell) change configuration, provided that the (re)configuration does not require any MN participation. In EN-DC and NR-DC, each of measConfig, radioBearerConfig, conditionalReconfiguration, otherConfig, and / or secondaryCellGroup can be included in the RRCReconfiguration sent / received via SRB3.

[0031] In some embodiments of a wireless communication system using MR-DC (e.g., using EN-DC or NR-DC), when the UE is operating in MR-DC mode with SRB3 configured, the UE may send any SCG measurement reports on SRB3. For example, the UE may utilize the SCG of the SN (wherein the SCG may consist of a SpCell and zero or more additional cells, which the UE may also use to send data to or receive data from the SN) by (at least) communicating on the SpCell of the SCG. These SCG measurement reports may allow the SN to react to changing SCG cell conditions (e.g., perform a handover of the UE to another SpCell of the target node). For example, it may be that the standard of the wireless communication system defines some or all of such behavior at the UE and / or SN.

[0032] Such measurement reports can be configured to be sent on the SpCell of the SCG. Therefore, when the SpCell of the SCG starts to degrade, the probability of receiving such SCG measurement reports on SRB3 at the SN also decreases. If the SCG measurement reports reflecting the degradation are not received at the SN, the SN may not react appropriately to the degradation nature of the SpCell (e.g., perform a handover to another SpCell) (because it is not yet aware of the degradation). From the UE's perspective, this may lead to SCG failure (e.g., RLF of the SpCell of the SCG), which may cause any service provided to the UE via the SN to be interrupted.

[0033] Figure 3 FIG. 300 is a flow chart showing that when a UE operates in the NR-DC mode, due to the degradation of the SCG SpCell, the SCG measurement report from the UE fails to reach the SN on SRB3 according to an embodiment. In Figure 3 , the UE functions have been divided into UE-MCG 302 showing the functions of the UE related to the MN / MCG and UE-SCG 304 showing the functions of the (same) UE related to the SN / SCG. The flow chart 300 also includes the SN 306 and MN 308 (where both MN 308 and SN 306 are NR nodes) communicating with the UE according to the NR-DC mode as previously described.

[0034] The flow chart 300 shows the configuration 310 of SRB1 and SRB2 at the UE-MCG 302. The flow chart 300 further shows the configuration 312 of SRB3 at the UE-SCG 304. Due to the previous configuration 312 of SRB3, the UE may perform SCG measurement reporting 314 on SRB3 between the UE-SCG 304 and the SN 306. As shown, at a certain point in time, the UE (at the UE-SCG 304) experiences SCG SpCell degradation 316. As part of this degradation operation, the UE-SCG 304 may attempt to provide the SN 306 with a SCG measurement report reflecting this degradation, which will ultimately cause the SN 306 to react to the SCG SpCell degradation 316 (e.g., use another cell of the target node (which may be the SN or a completely different node) as the SpCell via a handover). However, in the case of the flow chart 300, the SCG measurement report / retransmission 318 that is normally used for this purpose (and transmitted on the SCG SpCell) does not reach the SN 306 due to the SCG SpCell degradation 316. This is represented by using a dashed line for the SCG measurement report / retransmission 318.

[0035] Flowchart 300 further illustrates SCG failure 320 due to SCG SpCell RLF. Eventually, upon failure to communicate with SN 306 (e.g., no message delivery from SN 306 after a certain amount of time), the UE will recognize the SCG failure 320 condition and send SCG failure information 322 to MN 308.

[0036] Note that the UE's determination of SCG failure 320 may not occur immediately upon / after the non-reception of the SCG measurement report / retransmission 318. Instead, after starting a set of SCG measurement reports / retransmissions 318, it may take some time for the UE to conclude that the SCG failure 320 has occurred and then send the SCG failure information 322. During this time, the service from the network to the UE on the SN 306 may have been significantly affected.

[0037] Figure 4 400 shows a flow chart of an embodiment in which an SCG measurement report from a UE fails to reach the SN on SRB3 due to SCG SpCell degradation when the UE operates in EN-DC mode. Figure 4 4, the UE functionality has been separated into UE-MCG 402 showing the UE's functionality related to MN / MCG and UE-SCG 404 showing the (same) UE's functionality related to SN / SCG. Flowchart 400 also includes SN 406 and MN 408 (where MN 408 is an LTE node and SN 406 is an NR node) communicating with the UE according to EN-DC mode as previously described.

[0038] 4. The flowchart 400 illustrates the configuration 410 of SRB1 and SRB2 at the UE-MCG 402. The flowchart 400 further illustrates the configuration 412 of SRB3 at the UE-SCG 404. Due to the prior configuration 412 of SRB3, the UE may be subject to SCG measurement reporting 414 on SRB3 between the UE-SCG 404 and the SN 406. As shown, at some point in time, the UE (at the UE-SCG 404) experiences an SCG SpCell downgrade 416. As part of this downgrade operation, the UE-SCG 404 may attempt to provide an SCG measurement report reflecting the downgrade to the SN 406, which will ultimately cause the SN 406 to react to the SCG SpCell downgrade 416 (e.g., via handover to use another cell of the target node (which may be an SN or an entirely different node) as the SpCell). However, in the case of flowchart 400, an SCG measurement report / retransmission 418 that would normally be used for this purpose (and transmitted on the SCG SpCell) does not reach SN 406 due to SCG SpCell degradation 416. This is represented by the use of a dashed line for the SCG measurement report / retransmission 418.

[0039] Flowchart 400 further illustrates SCG failure 420 due to SCG SpCell RLF. Ultimately, upon failure to communicate with SN 406 (e.g., no message delivery from SN 406 after a certain amount of time), the UE will recognize the SCG failure 420 condition and send SCG failure information 422 to MN 408.

[0040] Note that the UE's determination of SCG failure 420 may not occur immediately upon / after the non-reception of the SCG measurement report / retransmission 418. Instead, after starting a set of SCG measurement reports / retransmissions 418, it may take some time for the UE to conclude that the SCG failure 420 has occurred and then send the SCG failure information 422. During this time, the service from the network to the UE on the SN 406 may have been significantly affected.

[0041] It has been recognized that when the SpCell of the SCG begins to degrade, the situation where measurement reports are conditionally triggered at the UE is also affected. For example, the UE can be configured to trigger an SCG measurement report (event A3) on SRB3 when the current SCG SpCell has a power level that is lower than a threshold amount (A3 condition) than a neighboring cell. This SCG measurement report (event A3) contains the power level of the SCGSpCell and the power level of the neighboring cell, and indicates (for example, by including a measurement ID corresponding to the A3 condition known to the network in the SCT measurement report) that an A3 condition exists between the SCG SpCell and the neighboring cell. Upon receiving this SCG measurement report, the SN 506 identifies the A3 condition between the SCG SpCell and the neighboring cell and initiates a handover to the neighboring cell. However, the A3 condition may be caused by the degradation of the SCG SpCell, and the SCG SpCell may have been degraded to the extent that the SCG measurement report (event A3) does not reach the SN. If this SCG measurement report reflecting the A3 condition is not received at the SN (event A3), the SN may not react appropriately to the A3 condition (e.g., perform a handover to a neighboring cell) (because it is not yet aware of the A3 condition). If the SCG SpCell continues to degrade, this may eventually lead to an SCG failure (e.g., RLF of the SCG SpCell) from the UE's perspective, which may result in interruption of any services provided to the UE by the SN.

[0042] Figure 5 Flowchart 500 shows that when the UE operates in NR-DC mode, the SCG measurement report from the UE fails to reach the SN on SRB3 due to SCG SpCell degradation according to an embodiment. Figure 5 5 , the UE functionality has been separated into a UE-MCG 502 showing the UE's MN / MCG related functionality and a UE-SCG 504 showing the (same) UE's SN / SCG related functionality. The flowchart 500 also includes an SN 506 and a MN 508 (where both the MN 508 and the SN 506 are NR nodes) communicating with the UE according to the NR-DC mode as previously described.

[0043] Flowchart 500 illustrates the configuration 510 of SRB1 and SRB2 at UE-MCG 502. Flowchart 500 further illustrates the configuration 512 of SRB3 at UE-SCG 504. As shown, a triggering item 514 for an SCG measurement report (event A3) 516 then occurs. In the case of triggering item 514, the SCG SpCell has been degraded, causing the power of the neighboring cell to be higher than the power of the SCG SpCell by an offset or threshold amount. Due to the previous configuration 512 of SRB3, the UE may have to perform a corresponding SCG measurement report (event A3) 516 on SRB3 between UE-SCG 504 and SN 506. However, in the case of flowchart 500, the SCG measurement report (event A3) 516 transmitted on the SCG SpCell (and any subsequent SCG measurement report (event A3) / retransmission 518) does not reach SN 506 due to the demotion of the SCG SpCell. This is represented by the use of dashed lines for SCG measurement report (event A3) 516 and SCG measurement report (event A3) / retransmission 518.

[0044] Flowchart 500 further illustrates SCG failure 520 due to SCG SpCell RLF. Ultimately, upon failure to communicate with SN 506 (e.g., no message delivery from SN 506 after a certain amount of time), the UE will recognize the SCG failure 520 condition and send SCG failure information 522 to MN 508.

[0045] Note that the UE's determination of SCG failure 520 may not occur immediately upon / after the non-reception of the SCG measurement report (event A3) 516 and / or the SCG measurement report (event A3) retransmission 518. Instead, after the start of the SCG measurement report (event A3) 516 and / or the SCG measurement report (event A3) retransmission 518, it may take some time for the UE to conclude that the SCG failure 520 has occurred and then send the SCG failure information 522. During this time, the service from the network to the UE on the SN 506 may have been significantly affected.

[0046] Figure 6 Flowchart 600 shows that when the UE operates in EN-DC mode, the SCG measurement report from the UE fails to reach the SN on SRB3 due to SCG SpCell degradation according to an embodiment. Figure 66, the UE functionality has been separated into UE-MCG 602 showing the UE's functionality related to MN / MCG and UE-SCG 604 showing the (same) UE's functionality related to SN / SCG. Flowchart 600 also includes SN 606 and MN 608 (where MN 608 is an LTE node and SN 606 is an NR node) communicating with the UE according to EN-DC mode as previously described.

[0047] Flowchart 600 illustrates the configuration 610 of SRB1 and SRB2 at UE-MCG 602. Flowchart 600 further illustrates the configuration 612 of SRB3 at UE-SCG 604. As shown, a triggering item 614 for an SCG measurement report (event A3) 616 then occurs. In the case of triggering item 614, the SCG SpCell has been degraded, causing the power of the neighboring cell to be higher than the power of the SCG SpCell by an offset or threshold amount. Due to the previous configuration 612 of SRB3, the UE may need to perform a corresponding SCG measurement report (event A3) 616 on SRB3 between UE-SCG 604 and SN 606. However, in the case of flowchart 600, the SCG measurement report (event A3) 616 transmitted on the SCG SpCell (and any subsequent SCG measurement report (event A3) / retransmission 618) does not reach SN 606 due to the demotion of the SCG SpCell. This is represented by the use of dashed lines for SCG measurement report (event A3) 616 and SCG measurement report (event A3) / retransmission 618.

[0048] Flowchart 600 further illustrates SCG failure 620 due to SCG SpCell RLF. Ultimately, upon failure to communicate with SN 606 (e.g., no message delivery from SN 606 after a certain amount of time), the UE will recognize the SCG failure 620 condition and send SCG failure information 622 to MN 608.

[0049] Note that the UE's determination of SCG failure 620 may not occur immediately upon / after the non-reception of the SCG measurement report (event A3) 616 and / or the SCG measurement report (event A3) retransmission 618. Instead, after the start of the SCG measurement report (event A3) 616 and / or the SCG measurement report (event A3) retransmission 618, it may take some time for the UE to conclude that the SCG failure 620 has occurred and then send the SCG failure information 622. During this time, the service from the network to the UE on the SN 606 may have been significantly affected.

[0050] Figure 7A flow chart 700 is shown of a system using NR-DC configured to send SCG measurement reports to both the MN and the SN in response to a handover condition associated with the SN and when SRB3 is configured between the UE and the SN, according to an embodiment. Figure 7 700 , the UE functionality has been divided into a UE-MCG 702 showing the functionality of the UE in relation to an MN / MCG and a UE-SCG 704 showing the functionality of the (same) UE in relation to one or more SN / SCGs. Flowchart 700 also includes an MN 706 and a source SN 708, which communicate with the UE according to the NR-DC mode as previously described at the start of flowchart 700 (where both MN 706 and source SN 708 are NR nodes). Before the end of flowchart 700, source SN 708 will be handed over to target SN 710. Note that in some cases, it is contemplated that source SN 708 and target SN 710 may be the same NR node, while in other cases, source SN 708 and target SN 710 may be different NR nodes.

[0051] Flowchart 700 illustrates configuration 712 of SRB1 and SRB2 at UE-MCG 702. Flowchart 700 further illustrates configuration 714 of SRB3 at UE-SCG 704. Due to the previous configuration 714 of SRB3, the UE may need to perform SCG measurement reporting 716 on SRB3 between UE-SCG 704 and source SN 708.

[0052] Flowchart 700 then illustrates that the SCG's SpCell begins to degrade, which results in a handover condition 718. Examples of handover conditions, as used in flowchart 700, may include an out-of-sync (OOS) counter beginning to increment, or a T310 timer running at the UE. For example, as the SCG's SpCell degrades, the UE may begin to lose synchronization with the SCG's SpCell. This is detected by lower layers at the UE, which send OOS indicators to the UE's RRC. These OOS indicators are reported at the UE-SCG 704 function using an incrementing OOS counter. Additionally, in some embodiments, once the OOS counter reaches a certain value, a T310 timer may be started, which the UE will use to determine when to report the RLF of the SCG SpCell to the MN. Thus, the UE of flowchart 700 may observe the incrementing of the OOS counter and / or the running of the T310 timer (as "handover condition 718") to trigger the balance of flowchart 700.

[0053] Once the handover condition 718 has been identified at the UE, the UE may responsively send an SCG measurement report. One or more of these SCG measurement reports may be sent as SCG measurement reports 720 from the UE-SCG 704 to the source SN 708 over SRB3 in the manner previously described (via RRC). However, the sending of the SCG measurement report 720 to the source SN 708 may fail due to SCG SpCell downgrade. The SCG measurement report is also provided 722 to the UE-MCG 702, which then sends the SCG measurement report as part of a ULInformationTransferMRDC message 724 (via E-UTRA-RRC) over SRB1 to the MN 706. The ULInformationTransferMRDC message 724 may be a message indicating to the receiving MN that the contents of such a message should be forwarded to the current SN. Note that, although not shown, the UE-MCG 702 may continue to (re)send ULInformationTransferMRDC messages 724 (possibly with updated SCG measurement reports) on SRB1 until handover of the UE to the target SN 710 is eventually achieved (or SCG SpCell conditions improve).

[0054] As shown, once the MN 706 receives the ULInformationTransferMRDC message 724, the SCG measurement report 726 is forwarded to the source SN 708. Figure 7 In the embodiment of , even if the SCG measurement report 720 fails, the information may still reach the source SN 708 anyway because the information is (also) sent by the UE-MCG 702 to the MN 706 and forwarded from the MN to the source SN 708.

[0055] like Figure 7 As shown, the source SN 708, having received the SCG measurement report 726 from the UE-MCG 702, is thus able to identify relevant aspects of the condition of the downgraded SCG SpCell based on the contents of the source SN 708. For example, the SCG measurement report 726 may indicate that the power level of the SCG SpCell at the UE is poor or otherwise unsuitable. The SCG measurement report 726 may also help identify suitable neighboring cells on the target SN 710 (e.g., based on the power of the neighboring cells as reported in the SCG measurement report 726). Therefore, the source SN 708 determines that a handover to the identified neighboring cell of the target SN 710 is appropriate and sends a handover request 728 to the target SN 710 to initiate this process.

[0056] The target SN 710 replies to the source SN 708 with a handover command 730, which is forwarded 732 to the MN 706. The MN 706 then sends an RRC connection reconfiguration message 734, which contains the SpCell handover message from the handover command 730 / 732, informing the UE-MCG 702 to handover to the identified neighboring cell on the target SN 710. A corresponding handover command 736 containing the SpCell handover message is generated by the UE-MCG 702 function and sent to the UE-SCG 704. The UE-SCG 704 then performs a SpCell change 738 on the neighboring cell.

[0057] To perform SpCell change 738, UE-SCG 704 switches to a neighboring cell of target SN 710 as directed by handover command 736. After the handover, this neighboring cell serves as the SpCell of UE-SCG 704. This SpCell has an associated SCG and SN (target SN 710).

[0058] Assume that the SN performing the handover determines that the neighboring cell to be handed over to is a cell of a different NR node. Figure 7 In this sense, the source SN 708 and the target SN 710 can be different NR nodes. It is envisaged that in these cases, the new SpCell will accordingly become part of a new SCG, which has zero or more additional cells as provided by the new NR node in addition to the cells of the SCG associated with the previous SpCell.

[0059] It is further envisaged that the target SN may be the same NR node as the current SN. For example, this is permitted if the SN performing the handover determines that the adjacent cell to be handed over to is another cell of the same NR node. Figure 7 In the sense that the source SN 708 and the target SN 710 may be the same NR node. It is envisioned that in these cases, the UE's new SpCell may be associated with an SCG consisting of a set of zero or more additional cells that are the same, different, or partially different than the SCG associated with the previous SpCell. In the case where, for example, the source SN 708 and the target SN 710 are the same NR node, the handover request 728 and handover command 730 shown in the figure may not be transmitted (or may be processed only internally to the same NR node).

[0060] After completing the SpCell change 738, the UE-SCG 704 function provides a Handover Complete message 740 to the UE-MCG 702 function of the UE. The UE-MCG 702 then sends an RRC Connection Reconfiguration Complete message 742 containing the Handover Complete message 740 to the MN 706, which then forwards 744 the Handover Complete message 740 to the target SN 710 to inform / confirm to the target SN 710 that the UE has completed the directed handover. At this stage, the UE-SCG 704 also stops 746 any measurement reporting on SRB1 associated with the handover condition 718 (as described above, these measurement reports may have been intentionally repeated before the handover was performed by the network).

[0061] With, for example, Figure 3 Compared to the implementation scheme found in Figure 7 A system for NR-DC that detects the handover condition 718 and reacts as described can be more responsive to the degradation of the SCG SpCell of the source SN 708. Thus, the risk that the service being provided by the source SN 708 (and, after handover, possibly the target SN 710) to the UE is substantially impeded is reduced.

[0062] Figure 8 A flow chart 800 is shown of a system using EN-DC configured to send SCG measurement reports to both the MN and the SN in response to handover conditions associated with the SN and when SRB3 is configured between the UE and the SN, according to an embodiment. Figure 8 800 , the UE functionality has been divided into UE-MCG 802 showing the functionality of the UE in relation to the MN / MCG and UE-SCG 804 showing the functionality of the (same) UE in relation to one or more SN / SCGs. Flowchart 800 also includes MN 806 and source SN 808, which, at the start of flowchart 800, communicate with the UE according to the EN-DC mode as previously described (wherein MN 806 is an LTE node and source SN 808 is an NR node). Before the end of flowchart 800, source SN 808 will be handed over to target SN 810. Note that in some cases, it is expected that source SN 808 and target SN 810 may be the same NR node, while in other cases, source SN 808 and target SN 810 may be different NR nodes.

[0063] Flowchart 800 illustrates configuration 812 of SRB1 and SRB2 at UE-MCG 802. Flowchart 800 further illustrates configuration 814 of SRB3 at UE-SCG 804. Due to the previous configuration 814 of SRB3, the UE may need to perform SCG measurement reporting 816 on SRB3 between UE-SCG 804 and source SN 808.

[0064] Flowchart 800 then illustrates that the SCG's SpCell begins to degrade, which results in a handover condition 818. Examples of handover conditions, as used in flowchart 800, may include an out-of-sync (OOS) counter beginning to increment, or a T310 timer running at the UE. For example, as the SCG's SpCell degrades, the UE may begin to lose synchronization with the SCG's SpCell. This is detected by lower layers at the UE, which send OOS indicators to the UE's RRC. These OOS indicators are reported at the UE-SCG 804 function using an incrementing OOS counter. Additionally, in some embodiments, once the OOS counter reaches a certain value, a T310 timer may be started, which the UE will use to determine when to report the RLF of the SCG SpCell to the MN. Thus, the UE of flowchart 800 may observe the incrementing of the OOS counter and / or the running of the T310 timer (as "handover condition 818") to trigger the balance of flowchart 800.

[0065] Once the handover condition 818 has been identified at the UE, the UE may responsively send an SCG measurement report. One or more of these SCG measurement reports may be sent as SCG measurement reports 820 from the UE-SCG 804 to the source SN 808 over SRB3 in the manner previously described. However, the sending of the SCG measurement report 820 to the source SN 808 may fail due to SCGSpCell downgrade. The SCG measurement report is also provided 822 to the UE-MCG 802, which then sends the SCG measurement report as part of a ULInformationTransferMRDC message 824 (via E-UTRA-RRC) over SRB1 to the MN 806. The ULInformationTransferMRDC message 824 may be a message indicating to the receiving MN that the contents of such a message should be forwarded to the current SN. Note that, although not shown, the UE-MCG 802 may continue to (re)send ULInformationTransferMRDC messages 824 (possibly with updated SCG measurement reports) on SRB1 until handover of the UE to the target SN 810 is eventually achieved (or SCG SpCell conditions improve).

[0066] As shown, once the MN 806 receives the ULInformationTransferMRDC message 824, the SCG measurement report 826 is forwarded to the source SN 808. Figure 8 In the embodiment of , even if the SCG measurement report 820 fails, the information may still reach the source SN 808 anyway because the information is (also) sent by the UE-MCG 802 to the MN 806 and forwarded from the MN to the source SN 808.

[0067] like Figure 8 As shown, the source SN 808, having received the SCG measurement report 826 from the UE-MCG 802, is thus able to identify relevant aspects of the condition of the downgraded SCG SpCell based on the contents of the source SN 808. For example, the SCG measurement report 826 may indicate that the power level of the SCG SpCell at the UE is poor or otherwise unsuitable. The SCG measurement report 826 may also help identify suitable neighboring cells on the target SN 810 (e.g., based on the power of the neighboring cells as reported in the SCG measurement report 826). Therefore, the source SN 808 determines that a handover to the identified neighboring cell of the target SN 810 is appropriate and sends a handover request 8281 to the target SN 810 to initiate this process.

[0068] The target SN 810 replies to the source SN 808 with a handover command 830, which is forwarded 832 to the MN 806. The MN 806 then sends an RRC connection reconfiguration message 834, which contains the SpCell handover message from the handover command 830 / 832, informing the UE-MCG 802 to handover to the identified neighboring cell on the target SN 810. A corresponding handover command 836 containing the SpCell handover message is generated by the UE-MCG 802 function and sent to the UE-SCG 804. The UE-SCG 804 then performs a SpCell change 838 on the neighboring cell.

[0069] To perform SpCell change 838, UE-SCG 804 switches to a neighboring cell of target SN 810 as directed by handover command 836. After the handover, this neighboring cell serves as the SpCell of UE-SCG 804. This SpCell has an associated SCG and SN (target SN 810).

[0070] Assume that the SN performing the handover determines that the neighboring cell to be handed over to is a cell of a different NR node. Figure 8In this sense, the source SN 808 and the target SN 810 can be different NR nodes. It is envisaged that in these cases, the new SpCell will accordingly become part of a new SCG, which has zero or more additional cells as provided by the new NR node in addition to the cells of the SCG associated with the previous SpCell.

[0071] It is further envisaged that the target SN may be the same NR node as the current SN. For example, this is permitted if the SN performing the handover determines that the adjacent cell to be handed over to is another cell of the same NR node. Figure 8 In the sense that the source SN 808 and the target SN 810 may be the same NR node. It is envisioned that in these cases, the UE's new SpCell may be associated with an SCG consisting of a set of zero or more additional cells that are the same, different, or partially different than the SCG associated with the previous SpCell. In the case where, for example, the source SN 808 and the target SN 810 are the same NR node, the handover request 828 and handover command 830 shown in the figure may not be transmitted (or may be processed only internally to the same NR node).

[0072] After completing the SpCell change 838, the UE-SCG 804 function provides a Handover Complete message 840 to the UE-MCG 802 function of the UE. The UE-MCG 802 then sends an RRC Connection Reconfiguration Complete message 842 containing the Handover Complete message 840 to the MN 806, which then forwards 844 the Handover Complete message 840 to the target SN 810 to inform / confirm to the target SN 810 that the UE has completed the directed handover. At this stage, the UE-SCG 804 also stops 846 any measurement reporting on SRB1 associated with the handover condition 818 (as described above, these measurement reports may have been intentionally repeated before the handover was performed by the network).

[0073] With, for example, Figure 4 Compared to the implementation scheme found in Figure 8 A system for EN-DC that detects the handover condition 818 and reacts as described can be more responsive to the degradation of the SCCG SpCell of the source SN 808. Therefore, the risk that the service being provided by the source SN 808 (and, after handover, possibly the target SN 810) to the UE is substantially impeded is reduced.

[0074] Figure 9A flow chart 900 is shown of a system using NR-DC configured to send SCG measurement reports to both the MN and the SN in response to a handover condition associated with the SN and when SRB3 is configured between the UE and the SN, according to an embodiment. Figure 9 900 , the UE functionality has been divided into a UE-MCG 902 showing the functionality of the UE in relation to an MN / MCG and a UE-SCG 904 showing the functionality of the (same) UE in relation to one or more SN / SCGs. Flowchart 900 also includes an MN 906 and a source SN 908, which communicate with the UE according to the NR-DC mode as previously described at the start of flowchart 900 (where both MN 906 and source SN 908 are NR nodes). Before the end of flowchart 900, source SN 908 will be handed over to target SN 910. Note that in some cases, it is expected that source SN 908 and target SN 910 may be the same NR node, while in other cases, source SN 908 and target SN 910 may be different NR nodes.

[0075] Flowchart 900 illustrates configuration 912 of SRB1 and SRB2 at UE-MCG 902. Flowchart 900 further illustrates configuration 914 of SRB3 at UE-SCG 904. Due to the previous configuration 914 of SRB3, the UE may need to perform SCG measurement reporting 916 on SRB3 between UE-SCG 904 and source SN 908.

[0076] The flowchart 900 then illustrates a handover condition 918, which is the UE's identification that the criteria for Event A3 have been met between the SCG SpCell and the neighboring cell of the source SN 908. For example, the UE may identify that the neighboring cell on the target SN 910 is higher by a threshold amount (e.g., higher power measured at the UE) than the SCG SpCell on the source SN 908.

[0077] Once the handover condition 918 has been identified at the UE, the UE may send an SCG measurement report (event A3). One or more of these SCG measurement reports may be sent as SCG measurement reports (event A3) 920 from the UE-SCG 904 to the source SN 908 over SRB3 in the manner previously described. However, sending the SCG measurement report (event A3) 920 to the source SN 908 may fail due to any degradation on the current SCG SpCell (e.g., where the cause of the degradation of the current SCG SpCell is an A3 condition between the SCG SpCell and a neighboring cell). The SCG measurement report is also provided 922 to the UE-MCG 902, which then sends the SCG measurement report as part of a ULInformationTransferMRDC message 924 (via RRC) over SRB1 to the MN 906. The ULInformationTransferMRDC message 924 may be a message indicating to the receiving MN that the contents of such a message should be forwarded to the current SN. Note that, although not shown, the UE-MCG 902 may continue to (re)send ULInformationTransferMRDC messages 924 (possibly with updated SCG measurement reports (event A3)) on SRB1 (via RRC) until handover of the UE to the target SN 910 is eventually achieved (or the SCG SpCell conditions improve).

[0078] As shown, once the MN 906 receives the ULInformationTransferMRDC message 924, the SCG measurement report 926 (event A3) is forwarded to the source SN 908. Figure 9 In the embodiment, even if the SCG measurement report 920 (event A3) fails, the information may still reach the source SN 908 anyway because the information is (also) sent by the UE-MCG 902 to the MN 906 and forwarded from the MN to the source SN 908.

[0079] like Figure 9 As shown, the source SN 908, having received the SCG measurement report (event A3) 926 from the UE-MCG 902, is thereby notified of the existence of the A3 condition and the identity of the neighboring cell on the target SN 910. Accordingly, the source SN 908 determines that a handover to the identified neighboring cell of the target SN 910 is appropriate and sends a handover request 928 to the target SN 910 to initiate this procedure.

[0080] The target SN 910 replies to the source SN 908 with a handover command 930, which is forwarded 932 to the MN 906. The MN 906 then sends an RRC connection reconfiguration message 934, which contains the SpCell handover message from the handover command 930 / 932, informing the UE-MCG 902 to handover to the identified neighboring cell of the target SN 910. A corresponding handover command 936 containing the SpCell handover message is generated by the UE-MCG 902 function and sent to the UE-SCG 904. The UE-SCG 904 then performs a SpCell change 938 on the neighboring cell.

[0081] To perform SpCell change 938, UE-SCG 904 switches to a neighboring cell of target SN 910 as directed by handover command 936. After the handover, this neighboring cell serves as the SpCell of UE-SCG 904. This SpCell has an associated SCG and SN (target SN 910).

[0082] Assume that the SN performing the handover determines that the neighboring cell to be handed over to is a cell of a different NR node. Figure 9 In this sense, the source SN 908 and the target SN 910 can be different NR nodes. It is envisaged that in these cases, the new SpCell will accordingly become part of a new SCG, which has zero or more additional cells as provided by the new NR node in addition to the cells of the SCG associated with the previous SpCell.

[0083] It is further envisaged that the target SN may be the same NR node as the current SN. For example, this is permitted if the SN performing the handover determines that the adjacent cell to be handed over to is another cell of the same NR node. Figure 9 In the sense that the source SN 908 and the target SN 910 may be the same NR node. It is envisioned that in these cases, the UE's new SpCell may be associated with an SCG consisting of a set of zero or more additional cells that are the same, different, or partially different than the SCG associated with the previous SpCell. In the case where, for example, the source SN 908 and the target SN 910 are the same NR node, the handover request 928 and handover command 930 shown in the figure may not be transmitted (or may be processed only internally to the same NR node).

[0084] After completing the SpCell change 938, the UE-SCG 904 function provides a Handover Complete message 940 to the UE-MCG 902 function of the UE. The UE-MCG 902 then sends an RRC Connection Reconfiguration Complete message 942, which contains the Handover Complete message 940 to the MN 906, which forwards 944 the Handover Complete message 940 to the target SN 910 to inform / confirm to the target SN 910 that the UE has completed the directed handover. At this stage, the UE-SCG 904 also stops 946 any measurement reporting on SRB1 associated with the handover condition 918 (as described above, these measurement reports may have been intentionally repeated before the handover was performed by the network).

[0085] With, for example, Figure 5 Compared to the implementation scheme found in Figure 9 A system for NR-DC that detects the handover condition 918 and reacts as described can be more responsive to the possible degradation (which may be caused by the A3 condition) of the SCG SpCell of the source SN 908. Thus, the risk that the service being provided by the source SN 908 (and, after handover, possibly the target SN 910) to the UE is substantially impeded is reduced.

[0086] Figure 10 A flow chart 1000 is shown of a system using EN-DC configured to send SCG measurement reports to both the MN and the SN in response to a handover condition associated with the SN and when SRB3 is configured between the UE and the SN, according to an embodiment. Figure 10 1000 , the UE functionality has been divided into a UE-MCG 1002 showing the functionality of the UE in relation to an MN / MCG and a UE-SCG 1004 showing the functionality of the (same) UE in relation to one or more SN / SCGs. Flowchart 1000 also includes a MN 1006 and a source SN 1008, which at the start of flowchart 1000 communicate with the UE according to the EN-DC mode as previously described (wherein the MN 1006 is an LTE node and the source SN 1008 is an NR node). Before the end of flowchart 1000, the source SN 1008 will be handed over to the target SN 1010. Note that in some cases, it is contemplated that the source SN 1008 and the target SN 1010 may be the same NR node, while in other cases, the source SN 1008 and the target SN 1010 may be different NR nodes.

[0087] Flowchart 1000 illustrates configuration 1012 of SRB1 and SRB2 at UE-MCG 1002. Flowchart 1000 further illustrates configuration 1014 of SRB3 at UE-SCG 1004. Due to the previous configuration 1014 of SRB3, the UE may need to perform SCG measurement reporting 1016 on SRB3 between UE-SCG 1004 and source SN 1008.

[0088] The flow chart 1000 then illustrates a handover condition 1018, which is the UE's identification that the Event A3 criteria have been met between the SCG SpCell and the neighboring cell of the source SN 1008. For example, the UE may identify that the neighboring cell on the target SN 1010 is higher by a threshold amount (e.g., higher power measured at the UE) than the SCG SpCell on the source SN 1008.

[0089] Once the handover condition 1018 has been identified at the UE, the UE may send an SCG measurement report (event A3). One or more of these SCG measurement reports may be sent as SCG measurement reports (event A3) 1020 from the UE-SCG 1004 to the source SN 1008 over SRB3 in the manner previously described. However, sending the SCG measurement report (event A3) 1020 to the source SN 1008 may fail due to any degradation on the current SCG SpCell (e.g., where the cause of the degradation of the current SCG SpCell is an A3 condition between the SCG SpCell and a neighboring cell). The SCG measurement report is also provided 1022 to the UE-MCG 1002, which then sends the SCG measurement report as part of a ULInformationTransferMRDC message 1024 (via RRC) over SRB1 to the MN 1006. The ULInformationTransferMRDC message 1024 may be a message indicating to the receiving MN that the contents of such a message should be forwarded to the current SN. Note that, although not shown, the UE-MCG 1002 may continue to (re)send ULInformationTransferMRDC messages 1024 (possibly with updated SCG measurement reports (event A3)) on SRB1 (via RRC) until handover of the UE to the target SN 1010 is ultimately achieved (or SCGSpCell conditions improve).

[0090] As shown, once the MN 1006 receives the ULInformationTransferMRDC message 1024, the SCG measurement report 1026 (event A3) is forwarded to the source SN 1008. Figure 10In the embodiment, even if the SCG measurement report 1020 (event A3) fails, the information may still reach the source SN 1008 anyway because the information is (also) sent by the UE-MCG 1002 to the MN 1006 and forwarded from the MN to the source SN 1008.

[0091] like Figure 10 As shown, the source SN 1008, having received the SCG measurement report (event A3) 1026 from the UE-MCG 1002, is thereby notified of the existence of the A3 condition and the identity of the neighboring cell on the target SN 1010. Therefore, the source SN 1008 determines that a handover to the identified neighboring cell of the target SN 1010 is appropriate and sends a handover request 1028 to the target SN 1010 to initiate this process.

[0092] The target SN 1010 replies to the source SN 1008 with a handover command 1030, which is forwarded 1032 to the MN 1006. The MN 1006 then sends an RRC connection reconfiguration message 1034, which contains the SpCell handover message from the handover command 1030 / 1032, informing the UE-MCG 1002 to handover to the identified neighboring cell of the target SN 1010. A corresponding handover command 1036 containing the SpCell handover message is generated by the UE-MCG 1002 function and sent to the UE-SCG 1004. The UE-SCG 1004 then performs a SpCell change 1038 on the neighboring cell.

[0093] To perform SpCell change 1038, UE-SCG 1004 switches to a neighboring cell of target SN 1010 as directed by handover command 1036. After the handover, this neighboring cell serves as the SpCell of UE-SCG 1004. This SpCell has an associated SCG and SN (target SN 1010).

[0094] Assume that the SN performing the handover determines that the neighboring cell to be handed over to is a cell of a different NR node. Figure 10 In this sense, the source SN 1008 and the target SN 1010 can be different NR nodes. It is envisaged that in these cases, the new SpCell will accordingly become part of a new SCG, which has zero or more additional cells as provided by the new NR node in addition to the cells of the SCG associated with the previous SpCell.

[0095] It is further envisaged that the target SN may be the same NR node as the current SN. For example, this is permitted if the SN performing the handover determines that the adjacent cell to be handed over to is another cell of the same NR node. Figure 10In the sense that the source SN 1008 and the target SN 1010 may be the same NR node. It is envisioned that in these cases, the UE's new SpCell may be associated with an SCG consisting of a set of zero or more additional cells that are the same, different, or partially different than the SCG associated with the previous SpCell. In the case where, for example, the source SN 1008 and the target SN 1010 are the same NR node, the handover request 1028 and handover command 1030 shown in the figure may not be transmitted (or may be processed only internally to the same NR node).

[0096] After completing the SpCell change 1038, the UE-SCG 1004 function provides a Handover Complete message 1040 to the UE-MCG 1002 function of the UE. The UE-MCG 1002 then sends an RRC Connection Reconfiguration Complete message 1042, which contains the Handover Complete message 1040 to the MN 1006, which forwards 1044 the Handover Complete message 1040 to the target SN 1010 to inform / confirm to the target SN 1010 that the UE has completed the directed handover. At this stage, the UE-SCG 1004 also stops 1046 any measurement reporting on SRB1 associated with the handover condition 1018 (as described above, these measurement reports may have been intentionally repeated before the handover was performed by the network).

[0097] With, for example, Figure 6 Compared to the implementation scheme found in Figure 10 A system for EN-DC that detects the handover condition 1018 and reacts as described can be more responsive to a possible degradation (which may be caused by an A3 condition) of the SCG SpCell of the source SN 1008. Thus, the risk that the service being provided by the source SN 1008 (and, after handover, possibly the target SN 1010) to the UE is substantially impeded is reduced.

[0098] Figure 11 A method 1100 of a UE operating in MR-DC mode with a MN and a SN according to an embodiment is shown. The method 1100 includes identifying 1102 a handover condition of a SpCell that satisfies an SCG of the SN.

[0099] The method 1100 further includes sending 1104 the SCG measurement report to the SN on the first SRB. This may occur in response to identifying 1102 that the handover condition of the SpCell of the SCG of the SN is met.

[0100] The method 1100 further includes sending 1106 the SCG measurement report to the MN on the second SRB. This may occur in response to identifying 1102 that the handover condition of the SpCell of the SCG of the SN is met.

[0101] In some embodiments of the method 1100, identifying 1102 that a handover condition for the SpCell is satisfied includes identifying that a neighboring cell of the target node is better than the SpCell by a threshold amount.

[0102] In some embodiments of the method 1100, identifying 1102 that a handover condition for the SpCell is met includes identifying that one or more OOS indications have been received from a lower layer.

[0103] In some embodiments of method 1100, identifying 1102 that a handover condition for the SpCell is met includes identifying that a T310 timer is running at the UE.

[0104] In some embodiments of method 1100, the SCG measurement report sent to the MN on the second SRB is sent in a ULInformationTransferMRDC message.

[0105] In some embodiments of method 1100, the first SRB is SRB3 and the second SRB is SRB1.

[0106] In some implementations of method 1100, the SCG of the SN includes multiple cells including SpCells.

[0107] In some embodiments of method 1100, the MR-DC mode is an NR-DC mode.

[0108] In some embodiments of method 1100, the MR-DC mode is an EN-DC mode.

[0109] Embodiments contemplated herein include an apparatus comprising means for performing one or more elements of the method 1200. The apparatus may be, for example, an apparatus of the UE 1300 as described below.

[0110] The embodiments contemplated herein include one or more non-transitory computer-readable media including instructions that, when executed by one or more processors of an electronic device, cause the electronic device to perform one or more elements of method 1100. The non-transitory computer-readable medium may be, for example, the memory 1306 of the UE 1300 described below and / or the peripherals 1504, memory / storage 1514, and / or database 1520 of the component 1500 described below.

[0111] Embodiments contemplated herein include an apparatus comprising logic, modules, or circuits operable to perform one or more elements of the method 1100. The apparatus may be, for example, an apparatus of the UE 1300 as described below.

[0112] Embodiments contemplated herein include an apparatus comprising one or more processors and one or more computer-readable media comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform one or more elements of method 1100. The apparatus may be, for example, a UE 1300 as described below.

[0113] Implementations contemplated herein include signals as described in or related to one or more elements of method 1100 .

[0114] Embodiments contemplated herein include a computer program comprising instructions, wherein execution of the program by a processing element causes the processing element to perform one or more elements of method 1100. These instructions may be, for example, instructions 1512 of component 1500 as described below.

[0115] Figure 12 A method 1200 is shown in which a SN and a UE may operate using MR-DC mode with a MN and a SN according to an embodiment. The method 1200 includes establishing 1202 an SRB with the UE.

[0116] The method 1200 further includes receiving 1204 an SCG measurement report from the MN.

[0117] The method 1200 further includes determining 1206 to perform a handover from the SpCell of the SN to a neighboring cell of the target node based on the content of the SCG measurement report.

[0118] The method 1200 also includes sending 1208 a handover request to the target node. This may occur if the SN is a different NR node than the target node, but may not occur if the SN is the same NR node as the target node.

[0119] In some embodiments of method 1200, determining 1206 to perform switching based on the contents of the SCG measurement report includes comparing a difference between a power level of the SpCell of the SN from the SCG measurement report and a power level of a neighboring cell of the target node from the SCG measurement report with a threshold amount.

[0120] In some embodiments of method 1200, the SRB is SRB3.

[0121] In some embodiments of method 1200, MR-DC is an NR-DC mode.

[0122] In some embodiments of method 1200, the MR-DC mode is an EN-DC mode.

[0123] In some implementations of method 1200, the target node is a SN.

[0124] Embodiments contemplated herein include an apparatus comprising means for performing one or more elements of the method 1200. The apparatus may be, for example, an apparatus of the network node 1400 as described below.

[0125] The embodiments contemplated herein include one or more non-transitory computer-readable media including instructions that, when executed by one or more processors of an electronic device, cause the electronic device to perform one or more elements of method 1200. The non-transitory computer-readable medium may be, for example, the memory 1406 of the UE network node 1400 described below and / or the peripheral device 1504, memory / storage device 1514, and / or database 1520 of the component 1500 described below.

[0126] Embodiments contemplated herein include an apparatus comprising logic, modules, or circuits operable to perform one or more elements of the method 1200. The apparatus may be, for example, an apparatus of the network node 1400 as described below.

[0127] Embodiments contemplated herein include an apparatus comprising one or more processors and one or more computer-readable media comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform one or more elements of method 1200. The apparatus may be, for example, a network node 1400 as described below.

[0128] Implementations contemplated herein include signals as described in or related to one or more elements of method 1200 .

[0129] Embodiments contemplated herein include a computer program comprising instructions, wherein execution of the program by a processing element causes the processing element to perform one or more elements of method 1200. These instructions may be, for example, instructions 1512 of component 1500 as described below.

[0130] Figure 13 1300 is a block diagram of an exemplary UE 1300 that can be configured according to various embodiments of the present disclosure, including by executing instructions corresponding to any of the exemplary methods and / or processes described herein on a computer-readable medium. The UE 1300 includes one or more processors 1302, a transceiver 1304, a memory 1306, a user interface 1308, and a control interface 1310.

[0131] The one or more processors 1302 may include, for example, an application processor, an audio digital signal processor, a central processing unit, and / or one or more baseband processors. Each of the one or more processors 1302 may include internal memory and / or may include an interface for communicating with external memory (including memory 1306). The internal or external memory may store software code, programs, and / or instructions for execution by the one or more processors 1302 to configure and / or facilitate the UE 1300 to perform various operations, including the operations described herein. For example, execution of the instructions may configure the UE 1300 to communicate using one or more wired or wireless communication protocols (including one or more wireless communication protocols standardized by 3GPP, such as those commonly referred to as 5G / NR, LTE, LTE-A, UMTS, HSPA, GSM, GPRS, EDGE, etc.) or any other current or future protocol that may be used in conjunction with the one or more transceivers 1304, the user interface 1308, and / or the control interface 1310. For another example, the one or more processors 1302 may execute program code stored in the memory 1306 or other memory corresponding to the MAC, RLC, PDCP, and RRC layer protocols standardized by 3GPP (e.g., for NR and / or LTE). For another example, the processor 1302 may execute program code stored in the memory 1306 or other memory that, together with the one or more transceivers 1304, implements corresponding PHY layer protocols such as orthogonal frequency division multiplexing (OFDM), orthogonal frequency division multiple access (OFDMA), and single carrier frequency division multiple access (SC-FDMA).

[0132] The memory 1306 may include a memory area for one or more processors 1302 to store variables used in protocols, configurations, controls, and other functions of the UE 1300 (including operations corresponding to or including any of the exemplary methods and / or processes described herein). In addition, the memory 1306 may include non-volatile memory (e.g., flash memory), volatile memory (e.g., static or dynamic RAM), or a combination thereof. In addition, the memory 1306 may interact with a memory slot through which removable memory cards of one or more formats (e.g., SD card, memory stick, compact flash, etc.) may be inserted and removed.

[0133] One or more transceivers 1304 may include radio frequency transmitter and / or receiver circuitry that facilitates communication between the UE 1300 and other equipment supporting similar wireless communication standards and / or protocols. For example, the one or more transceivers 1304 may include switches, mixer circuitry, amplifier circuitry, filter circuitry, and synthesizer circuitry. Such RF circuitry may include a receive signal path having circuitry for downconverting RF signals received from a front-end module (FEM) and providing the baseband signal to a baseband processor of the one or more processors 1302. The RF circuitry may also include a transmit signal path having circuitry for upconverting the baseband signal provided by the baseband processor and providing an RF output signal to the FEM for transmission. The FEM may include a receive signal path having circuitry configured to operate on RF signals received from one or more antennas, amplify the received signal, and provide the amplified version of the received signal to the RF circuitry for further processing. The FEM may also include a transmit signal path having circuitry configured to amplify transmit signals provided by the RF circuitry for transmission from the one or more antennas. In various embodiments, amplification through the transmit or receive signal path may be accomplished in only the RF circuitry, only the FEM, or in both the RF circuitry and the FEM circuitry. In some embodiments, the FEM circuitry may include a TX / RX switch to switch between transmit and receive mode operation.

[0134] In some exemplary embodiments, one or more transceivers 1304 include transmitters and receivers that enable UE 1300 to communicate with various 5G / NR networks in accordance with various protocols and / or methods proposed for standardization by 3GPP and / or other standards bodies. For example, such functionality may operate in cooperation with one or more processors 1302 to implement a PHY layer based on OFDM, OFDMA, and / or SC-FDMA techniques, such as described herein with reference to other figures.

[0135] The user interface 1308 may take various forms depending on the specific embodiment, or may not be present in the UE 1300. In some embodiments, the user interface 1308 includes a microphone, a speaker, a slidable button, a depressible button, a display, a touch screen display, a mechanical or virtual keypad, a mechanical or virtual keyboard, and / or any other user interface features typically present on a mobile phone. In other embodiments, the UE 1300 may include a tablet computing device with a larger touch screen display. In such embodiments, one or more of the mechanical features of the user interface 1308 may be replaced by comparable or functionally equivalent virtual user interface features (e.g., a virtual keypad, virtual buttons, etc.) implemented using a touch screen display, as will be familiar to those skilled in the art. In other embodiments, the UE 1300 may be a digital computing device, such as a laptop computer, a desktop computer, a workstation, etc., that includes a mechanical keyboard that may be integrated, detachable, or removable according to a specific exemplary embodiment. Such a digital computing device may also include a touch screen display. Many exemplary embodiments of the UE 1300 with a touch screen display are capable of receiving user input, such as input related to the exemplary methods and / or processes described herein or known to one of ordinary skill in the art.

[0136] In some exemplary embodiments of the present disclosure, UE 1300 includes an orientation sensor that can be used in various ways by the features and functions of UE 1300. For example, UE 1300 can use the output of the orientation sensor to determine when a user has changed the physical orientation of the touch screen display of UE 1300. The indication signal from the orientation sensor can be used for any application executed on UE 1300, so that the application can automatically change the orientation of the screen display (e.g., from portrait to landscape) when the indication signal indicates an approximately 90-degree change in the physical orientation of the device. In this way, regardless of the physical orientation of the device, the application can maintain the screen display in a user-readable manner. In addition, the output of the orientation sensor can be used in conjunction with various exemplary embodiments of the present disclosure.

[0137] The control interface 1310 can take various forms depending on the particular implementation. For example, the control interface 1310 can include an RS-232 interface, an RS-485 interface, a USB interface, an HDMI interface, a Bluetooth interface, an IEEE ("FireWire") interface, an I 2 C interface, PCMCIA interface, etc. In some exemplary embodiments of the present disclosure, the control interface 1260 may include an IEEE 802.3 Ethernet interface, such as described above. In some exemplary embodiments of the present disclosure, the control interface 1310 may include an analog interface circuit, which includes, for example, one or more digital-to-analog (D / A) converters and / or analog-to-digital (A / D) converters.

[0138] One of ordinary skill in the art will recognize that the above list of features, interfaces, and radio frequency communication standards is merely exemplary and does not limit the scope of the present disclosure. Figure 13 The UE 1300 may include further functionality, including, for example, a video and / or still image camera, a microphone, a media player and / or recorder, and the like. Furthermore, the one or more transceivers 1304 may include circuitry for communicating using additional radio frequency communication standards, including Bluetooth, GPS, and / or others. Furthermore, the one or more processors 1302 may execute software code stored in the memory 1306 to control such additional functionality. For example, the directional velocity and / or position estimate output from the GPS receiver may be used by any application executing on the UE 1300, including various exemplary methods and / or computer-readable media according to various exemplary embodiments of the present disclosure.

[0139] Figure 14 is a block diagram of an exemplary network node 1400 configurable according to various embodiments of the present disclosure, including by executing instructions on a computer-readable medium corresponding to any of the exemplary methods and / or processes described herein.

[0140] The network node 1400 includes one or more processors 1402, a radio network interface 1404, a memory 1406, a core network interface 1408, and other interfaces 1410. The network node 1400 may include, for example, a base station, an eNB, a gNB, an access node, or a component of a network node. The network node 1400 may include an LTE node or a NR node, as these terms are used in this disclosure.

[0141] The one or more processors 1402 may include any type of processor or processing circuit and may be configured to perform one of the methods or processes disclosed herein. The memory 1406 may store software code, programs, and / or instructions executed by the one or more processors 1402 to configure the network node 1400 to perform various operations, including the operations described herein. For example, execution of such stored instructions may configure the network node 1400 to communicate with one or more other devices using protocols according to various embodiments of the present disclosure (including one or more methods and / or processes discussed above). In addition, execution of such stored instructions may also configure and / or facilitate the network node 1400 to communicate with one or more other devices using other protocols or protocol layers (such as one or more of the PHY, MAC, RLC, PDCP, and RRC layer protocols standardized by 3GPP for LTE, LTE-A, and / or NR, or any other higher layer protocols used in conjunction with the radio network interface 1404 and the core network interface 1408). By way of example and not limitation, the core network interface 1408 includes an S1 interface, and the radio network interface 1404 may include a Uu interface, such as standardized by 3GPP. The memory 1406 may also store variables used in protocols, configuration, control, and other functions of the network node 1400. Thus, the memory 1406 may include non-volatile memory (e.g., flash memory, hard disk, etc.), volatile memory (e.g., static or dynamic RAM), network-based (e.g., "cloud") storage, or a combination thereof.

[0142] The radio network interface 1404 may include a transmitter, a receiver, a signal processor, an ASIC, an antenna, a beamforming unit, and other circuitry that enables the network node 1400 to communicate with other equipment (in some embodiments, such as multiple compatible user equipment (UE)). In some embodiments, the network node 1400 may include various protocols or protocol layers, such as the PHY, MAC, RLC, PDCP, and RRC layer protocols standardized by 3GPP for LTE, LTE-A, and / or 5G / NR. According to further embodiments of the present disclosure, the radio network interface 1404 may include a PHY layer based on OFDM, OFDMA, and / or SC-FDMA technology. In some embodiments, the functionality of such a PHY layer may be provided collaboratively by the radio network interface 1404 and one or more processors 1402.

[0143] The core network interface 1408 may include transmitters, receivers, and other circuits that enable the network node 1400 to communicate with other equipment in the core network (in some embodiments, such as a circuit-switched (CS) and / or packet-switched core (PS) network). In some embodiments, the core network interface 1408 may include an S1 interface standardized by 3GPP. In some embodiments, the core network interface 1408 may include one or more interfaces to one or more SGWs, MMEs, SGSNs, GGSNs, and other physical devices, including functions known to those skilled in the art that exist in GERAN, UTRAN, E-UTRAN, and CDMA2000 core networks. In some embodiments, these one or more interfaces may be multiplexed together on a single physical interface. In some embodiments, the lower layers of the core network interface 1408 may include one or more of asynchronous transfer mode (ATM), Internet Protocol (IP) over Ethernet, SDH over fiber, T1 / E1 / PDH over copper, microwave radio, or other wired or wireless transmission technologies known to those skilled in the art.

[0144] Other interfaces 1410 may include transmitters, receivers, and other circuits that enable network node 1400 to communicate with external networks, computers, databases, etc., for operation, management, and maintenance of network node 1400 or other network equipment operably connected to the network node.

[0145] Figure 15 is a block diagram illustrating a component 1500 capable of reading instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium) and capable of performing any one or more of the methods discussed herein, according to some example embodiments. Specifically, Figure 15 A schematic diagram of hardware resources 1502 is shown, including one or more processors 1506 (or processor cores), one or more memory / storage devices 1514, and one or more communication resources 1524, each of which may be communicatively coupled via a bus 1516. For embodiments in which node virtualization (e.g., NFV) is utilized, a hypervisor 1522 may be executed to provide an execution environment for one or more network slices / subslices to utilize the hardware resources 1502. Component 1500 may be included, for example, in a UE or a network node as described herein.

[0146] Processor 1506 (e.g., a central processing unit (CPU), a reduced instruction set computing (RISC) processor, a complex instruction set computing (CISC) processor, a graphics processing unit (GPU), a digital signal processor (DSP) (such as a baseband processor), an application specific integrated circuit (ASIC), a radio frequency integrated circuit (RFIC), another processor, or any suitable combination thereof) may include, for example, processor 1508 and processor 1510.

[0147] The memory / storage device 1514 may include main memory, disk storage, or any suitable combination thereof. The memory / storage device 1514 may include, but is not limited to, any type of volatile or non-volatile memory, such as dynamic random access memory (DRAM), static random access memory (SRAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, solid-state storage, etc.

[0148] The communication resources 1524 may include interconnect or network interface components or other suitable devices to communicate with one or more peripheral devices 1504 or one or more databases 1520 via the network 1518. For example, the communication resources 1524 may include wired communication components (e.g., for coupling via a universal serial bus (USB)), cellular communication components, NFC components, Components (e.g. Low power consumption), components and other communication components.

[0149] The instructions 1512 may include software, a program, an application, an applet, an application, or other executable code for causing at least one of the processors 1506 to perform any one or more of the methods discussed herein. The instructions 1512 may reside entirely or partially within at least one of the processors 1506 (e.g., within a cache memory of the processor), the memory / storage device 1514, or any suitable combination thereof. Furthermore, any portion of the instructions 1512 may be transferred to the hardware resources 1502 from any combination of the peripheral devices 1504 or the database 1520. Thus, the memory of the processor 1506, the memory / storage device 1514, the peripheral devices 1504, and the database 1520 are examples of computer-readable and machine-readable media.

[0150] For one or more embodiments, at least one of the components shown in one or more of the foregoing figures may be configured to perform one or more operations, techniques, processes, and / or methods as described herein. For example, the baseband circuitry described above in conjunction with one or more of the foregoing figures may be configured to operate according to one or more of the examples described herein. For another example, circuitry associated with a UE, base station, network element, etc., as described above in conjunction with one or more of the foregoing figures, may be configured to operate according to one or more of the examples described herein.

[0151] Unless expressly stated otherwise, any of the above embodiments may be combined with any other embodiment (or combination of embodiments). The foregoing description of one or more specific implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of the embodiments to the precise forms disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the various embodiments.

[0152] Embodiments and implementations of the systems and methods described herein may include various operations that may be embodied in machine-executable instructions to be executed by a computer system. A computer system may include one or more general-purpose or special-purpose computers (or other electronic devices). A computer system may include hardware components that include specific logic components for performing the operations, or may include a combination of hardware, software, and / or firmware.

[0153] It should be understood that the systems described herein include descriptions of specific embodiments. These embodiments can be combined into a single system, partially integrated into other systems, separated into multiple systems, or otherwise divided or combined. In addition, it is contemplated that parameters, attributes, aspects, etc. of one embodiment can be used in another embodiment. For clarity, these parameters, attributes, aspects, etc. are described only in one or more embodiments, and it should be understood that unless otherwise stated herein, these parameters, attributes, aspects, etc. can be combined with or substituted for parameters, attributes, aspects, etc. of another embodiment.

[0154] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly stated to users.

[0155] Although the foregoing has been described in considerable detail for purposes of clarity, it will be apparent that certain changes and modifications may be made without departing from the principles of the invention. It should be noted that there are many alternative ways of implementing both the processes and the apparatus described herein. The embodiments of the present invention are therefore to be considered illustrative and not restrictive, and the description is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.

Claims

1. A method for operating a user equipment (UE) in a multi-radio dual connectivity (MR-DC) mode with a primary node (MN) and a secondary node (SN), the method comprising: Before a radio link failure RLF of a special cell SpCell of a secondary cell group SCG of the SN occurs, a handover condition identifying degradation of the SpCell corresponding to the SCG of the SN is detected at the UE; and In response to identifying the handover condition corresponding to degradation of the SpCell being detected at the UE: Sending an SCG measurement report to the SN on a first signaling radio bearer (SRB); as well as The SCG measurement report is sent to the MN on a second SRB.

2. The method of claim 1 , wherein identifying that the handover condition corresponding to degradation of the SpCell is detected at the UE comprises: Identifies a neighboring cell of the target node that is better than the SpCell by a threshold amount.

3. The method of claim 1 , wherein identifying that the handover condition corresponding to degradation of the SpCell is detected at the UE comprises: Identifies that one or more Out-of-Sync OOS indications have been received from lower layers.

4. The method of claim 1 , wherein identifying that the handover condition corresponding to degradation of the SpCell is detected at the UE comprises: It is identified that the T310 timer is running at the UE.

5. The method of claim 1, wherein the SCG measurement report sent to the MN on the second SRB is sent in a ULInformationTransferMRDC message. The method of claim 1 , wherein the first SRB is SRB3 and the second SRB is SRB1.

7. The method according to claim 1, wherein the SCG of the SN includes a plurality of cells including the SpCell.

8. The method according to claim 1, wherein the MR-DC mode is a New Radio (NR-NR) dual connectivity (NR-DC) mode.

9. The method according to claim 1, wherein the MR-DC mode is an Evolved Universal Terrestrial Radio Access (E-UTRA)-New Radio (NR) dual connectivity (EN-DC) mode.

10. A device for wireless communication, comprising: one or more processors; A memory storing instructions which, when executed by the one or more processors, cause the method according to any one of claims 1 to 9 to be performed.

11. A computer readable medium having stored thereon a computer program which, when executed by one or more processors, causes a device to perform the steps of the method according to any one of claims 1 to 9.

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