NETWORK NODE, COMMUNICATION DEVICE AND METHOD FOR HANDLING RESUME PROCEDURES IN A WIRELESS COMMUNICATION NETWORK - Patent application

Abstract

A method implemented in a communication device for handling a resume procedure from a power saving mode of operation to a connected mode of operation is disclosed. The communication device is configured with a multi-radio dual connectivity (MR-DC) with a first cell group and a second cell group in a wireless communication network. The method includes initiating a resume procedure when there is uplink (UL) data available at the communication device while the communication device is in a power saving mode of operation (13010), setting a UL data indication indicating whether the UL data is available for the first cell group or the second cell group (13050, 13060), and sending the UL data indication to a network node (13070).

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The embodiments herein relate to network nodes, communication devices and methods therein. In particular, the embodiments herein relate to handling resume procedures for communication devices operating in dual connectivity with a Master Cell Group (MCG) and a Secondary Cell Group (SCG) in a wireless communication network. [Background technology]

[0002] In a typical wireless communication network, wireless devices, also known as wireless communication devices, mobile stations, stations (STAs) and / or user equipment (UEs), communicate through a radio access network (RAN) to one or more core networks (CNs). The RAN covers a geographical area that is divided into service areas or cell areas, sometimes called beams or beam groups, and each service area or cell area is served by a radio network node, such as a radio access node, e.g., a Wi-Fi access point or a radio base station (RBS), which in some networks may be denoted as a "Node B" or an "eNode B" or a "gNB". A service area or cell area is a geographical area where radio coverage is provided by a radio network node. The radio network node communicates with wireless communication devices within range of the radio network node over an air interface operating on radio frequencies.

[0003] The Universal Mobile Telecommunications System (UMTS) is a third-generation (3G) communications network that evolved from the second-generation (2G) Global System for Mobile Communications (GSM). Specifications for the Evolved Packet System (EPS), also called fourth-generation (4G) networks, or Long Term Evolution (LTE), have been finalized within the Third Generation Partnership Project (3GPP), and this work continues, for example, in upcoming 3GPP releases to specify fifth-generation (5G) New Radio (NR) networks and upcoming releases.

[0004] Carrier Aggregation (CA): CA is used in wireless communication to increase the bandwidth and thus the data rate per user, and thus multiple frequency blocks, called component carriers, are allocated to the same user. When CA is configured, the UE has only one Radio Resource Control (RRC) connection with the network node. Furthermore, in RRC connection establishment / re-establishment / handover, one serving cell provides Non-Access Stratum (NAS) mobility information, and in RRC connection re-establishment / handover, one serving cell provides security input. This cell is called a Primary Cell (PCell). Furthermore, depending on the UE capabilities, a Secondary Cell (SCell) may be configured to form a set of serving cells together with the PCell. Thus, when carrier aggregation is configured for a UE, the set of serving cells used by the UE always consists of one PCell and one or more SCells.

[0005] Reconfiguration, addition and removal of SCells may be performed by the RRC. In an intra-radio access technology (intra-RAT) handover, the RRC may also add, remove or reconfigure a SCell for use with the target PCell. When adding a new SCell, dedicated RRC signaling is used to send all required system information of the SCell, i.e., the UE does not need to acquire broadcasted system information directly from the SCell while in connected mode.

[0006] 3GPP Dual Connectivity: In 3GPP Rel-12, the LTE feature Dual Connectivity (DC) was introduced to allow a UE to be connected in two cell groups, each controlled by an LTE access node and an eNB, labeled Master eNB (MeNB) and Secondary eNB (SeNB). The UE still has only one RRC connection with the network node. In 3GPP, Dual Connectivity (DC) solutions have evolved since then and are now specified for NR as well as between LTE and NR. With the introduction of 5G, the term Multi-Radio Dual Connectivity (MR-DC), see also 3GPP TS37.340, was defined as a generic term for all dual connectivity options that include at least one NR access node. Using the generalized terminology of MR-DC, a UE is connected in a Master Cell Group (MCG) controlled by a Master Node (MN) and in a Secondary Cell Group (SCG) controlled by a Secondary Node (SN).

[0007] Furthermore, in MR-DC, when dual connectivity is configured for a UE, carrier aggregation may also be used within each of the two cell groups, MCG and SCG. In this case, in the MCG controlled by the master node (MN), the UE may use one PCell and one or more SCells. And, in the SCG controlled by the secondary node (SN), the UE may use one primary SCell (PSCell), also known as a primary SCG cell in NR, and one or more SCells. This combined case, i.e., dual connectivity combined with carrier aggregation in MR-DC, is shown in FIG. 1, where MN 110, SN 120, UE 130, MCG 140, SCG 150, PCell 160 in MCG 140, PSCell 170 in SCG 150, and multiple SCells are shown. In NR, the primary cell of the master or secondary cell group is sometimes also called a special cell (SpCell). Therefore, an SpCell in an MCG is a PCell, and an SpCell in an SCG is a PSCell.

[0008] There are different ways to deploy 5G networks with or without interworking with LTE and Evolved Packet Core (EPC), also called E-UTRA. In principle, NR and LTE can be deployed without interworking, denoted by NR Standalone (SA) operation, also known as option 2, i.e., a gNB in ​​NR can be connected to a 5G Core Network (5GC) and an eNB in ​​LTE can be connected to an EPC without any interconnection between the two, also known as option 1.

[0009] On the other hand, the first supported version of NR uses dual connectivity, denoted as EN-DC (E-UTRAN-NR dual connectivity), also known as option 3, as shown in FIG. 2. In such a deployment, dual connectivity between NR and LTE is applied, where a UE 210 is connected to both an LTE access node LTE MeNB 220 using an LTE air interface LTE Uu 221 and an NR access node NR SgNB 230 using an NR air interface NR Uu 231. Furthermore, in EN-DC, an LTE access node acts as a master node, in this case known as a master eNB (MeNB), that controls a master cell group (MCG), and an NR access node acts as a secondary node, in this case sometimes also known as a secondary gNB (SgNB), that controls a secondary cell group. The SgNB may not have a control plane connection to the core network EPC 240, which is instead provided by the MeNB, in this case NR. This is also called "non-standalone NR" or, in short, "NSA NR". In this case, it should be noted that the functionality of the NR cells is limited and they are used for connected mode UEs as booster and / or diversity legs, but the UE cannot camp on these NR cells in RRC_IDLE state, where the UE is switched on but does not have an established RRC connection.

[0010] With the introduction of 5GC, other options may also be valid. As mentioned above, option 2 supports standalone NR deployments where a gNB is connected to 5GC. Similarly, LTE may also be connected to 5GC using option 5, also known as eLTE, E-UTRA / 5GC, or LTE / 5GC, and the node may be referred to as ng-eNB. In these cases, both NR and LTE are viewed as part of the NG-RAN, and both ng-eNB and gNB may be referred to as NG-RAN nodes.

[0011] It is worth noting that there are also other variants of dual connectivity between LTE and NR standardized as part of NG-RAN connected to 5GC. Under the umbrella of MR-DC, these include: EN-DC (Option 3): LTE is the master node and NR is the secondary node (with EPC CN as shown in Figure 2). NE-DC (option 4): NR is the master node and LTE is secondary (5GCN adopted). NGEN-DC (Option 7): LTE is the master node and NR is secondary (adopted by 5GCN). · NR-DC (variant of option 2): Dual connectivity where both the Master Node (MN) controlling the MCG and the Secondary Node (SN) controlling the SCG are NR (as shown in Figure 3, adopted by 5GCN).

[0012] Since the migration for these options may be different for different operators, it is possible to have deployments with multiple options in parallel in the same network, for example, an NR base station supporting options 2 and 4 and an eNB base station supporting options 3, 5, and 7 in the same network. In combination with the dual connectivity solution between LTE and NR, it is also possible to support CA (Carrier Aggregation) in each cell group, i.e., MCG and SCG, and dual connectivity between nodes on the same RAT, e.g., NR-NR DC. For LTE cells, the consequence of these different deployments is the coexistence of LTE cells associated with eNBs connected to EPC, 5GC, or both EPC and 5GC.

[0013] As mentioned above, DC is standardized for both LTE and E-UTRA-NR DC (EN-DC).

[0014] LTE DC and EN-DC are designed differently with regards to which node controls what. Essentially there are two options: 1) Centralized solutions, such as LTE-DC, 2) Decentralized solutions, such as EN-DC.

[0015] Figure 4 shows how the schematic control plane architecture for LTE DC, EN-DC and NR-DC looks. The main difference here is that in EN-DC and NR-DC the SN has a separate NR RRC entity. This means that the SN can also control the UE sometimes without the MN's knowledge, but often the SN needs to coordinate with the MN. In LTE-DC the RRC decisions always come from the MN, i.e. from the MN to the UE. However, note that the SN still decides the configuration of the SN, since only the SN itself has knowledge of what kind of resources, capabilities etc. the SN has.

[0016] For EN-DC and NR-DC, the main changes compared to LTE DC are: · Introduction of split Data Radio Bearers (DRBs) from the SN (known as SN terminated split DRBs). · Introduction of Split Signaling Radio Bearer (SRB) for RRC. · Introduction of direct SRB from SN (also known as SCG SRB or SRB3).

[0017] Figure 5 shows the user plane protocol architecture in MR-DC with EPC (EN-DC) from a network node perspective, where the network node can configure either E-UTRA Packet Data Convergence Protocol (PDCP) or NR PDCP for MN terminated MCG DRBs, but NR PDCP is always used for all other DRBs.

[0018] Figure 6 shows the user plane protocol architecture in MR-DC with 5GC (NGEN-DC, NE-DC and NR-DC) from the network node perspective. In MR-DC with 5GC, NR PDCP is always used for all data radio bearer (DRB) types. In NGEN-DC, E-UTRA Radio Link Control / Medium Access Control (RLC / MAC) is used in the MN and NR RLC / MAC is used in the SN. In NE-DC, NR RLC / MAC is used in the MN and E-UTRA RLC / MAC is used in the SN. In NR-DC, NR RLC / MAC is used in both the MN and SN.

[0019] Packet duplication: Packet duplication or Packet Data Convergence Protocol (PDCP) packet duplication, also known as PDCP duplication, is a feature that can be used to support ultra-reliable low latency (URLLC) use cases.

[0020] PDCP duplication can be configured in both Carrier Aggregation (CA) and Dual Connectivity (DC) modes.

[0021] According to 3GPP TS38.300 v16.1 and as shown in FIG. 7, when duplication is configured for a radio bearer by RRC, at least one secondary RLC entity is added to the radio bearer to handle the duplicated PDCP protocol data units (PDUs), where the logical channel corresponding to the primary radio link control (RLC) entity is referred to as the primary logical channel and the logical channel corresponding to the secondary RLC entity(ies) is referred to as the secondary logical channel(s).

[0022] Duplication in PDCP therefore consists in submitting the same PDCP PDU multiple times, i.e., once to each activated RLC entity for a radio bearer. Packet duplicates are transmitted over different carriers (cells). Packet duplication therefore increases reliability and reduces latency when there are multiple independent transmission paths, which is especially beneficial for URLLC services.

[0023] When configuring duplication for the DRB, the RRC also sets the state of PDCP duplication, either activated or deactivated, at configuration or reconfiguration. After configuration, the PDCP duplication state is then dynamically controlled by the MAC Control element, and in DC the UE applies MAC CE commands regardless of their origin, MCG or SCG.

[0024] SCG Power Saving Mode: To improve network energy efficiency and UE battery life for UEs in MR-DC, a Rel-17 work item was planned to introduce efficient SCG / SCell activation / deactivation. This may be especially important for MR-DC settings with NR SCG, since in 3GPP contributed document RP-190919 it was assessed that in some cases NR UE power consumption is 3-4 times higher than LTE.

[0025] 3GPP specifies the concept of a dormant SCell (in LTE) and dormancy-like behavior of an SCell (for NR).

[0026] In LTE, when a SCell is in a dormant state, such as a deactivated state, the UE does not need to monitor the corresponding physical downlink control channel (PDCCH) or PDSCH and cannot transmit in the corresponding uplink. However, unlike the deactivated state, the UE is required to perform and report channel quality indicator (CQI) measurements. A PUCCH SCell, i.e., a SCell with a PUCCH configured, cannot be in a dormant state.

[0027] In NR, the dormant-like behavior for SCell is realized using the concept of dormant bandwidth parts (BWPs). See Figure 8, an illustration of dormant-like behavior for SCell in NR. One dormant BWP may be configured for the SCell, which is one of the dedicated BWPs configured by the network node via RRC signaling. If the active BWP of the activated SCell is a dormant BWP, the UE stops monitoring the PDCCH on the SCell, but continues to perform channel state information (CSI) measurements, automatic gain control (AGC) and beam management, if configured. Downlink control information (DCI) is used to control entering / exiting the dormant BWP for one or more SCells or one or more SCell groups, and the DCI is sent to the special cell (SpCell) of the cell group to which the SCell belongs, i.e., the PCell if the SCell belongs to the MCG, and the PSCell if the SCell belongs to the SCG. A dormant BWP cannot be configured on the SpCell, i.e., the PCell of the PSCell, and the PUCCH SCell.

[0028] However, only the SCell can be put into a dormant state (in LTE) or operate in a dormant-like behavior (NR). Also, only the SCell can be put into a deactivated state in both LTE and NR. Therefore, when MR-DC is configured in the UE, it is not possible to fully benefit from the power saving option of dormant state or dormant-like behavior, because the feature cannot be configured in the PSCell. Instead, the existing solution can be to release an SCG for power saving as needed, and to add an SCG when traffic demand requires it. However, traffic can be bursty, and adding and releasing an SCG involves a significant amount of RRC signaling and inter-node messaging between the MN and the SN, which causes significant delays.

[0029] In 3GPP rel-16, there was some discussion about putting the PSCell into hibernation as well, also called SCG suspension. Some tentative agreement was reached in RAN2-107bis in October 2019 (see Chair's note in R2-1914301).

[0030] R2-1914301 assumes the following (which may be slightly modified with progress on Scell ​​dormancy): => The UE supports network controlled suspension of SCG in RRC_CONNECTED. => UE behavior for interrupted SCG is FFS. => The UE supports at most one SCG configuration in Rel16, suspended or non-suspended. => In RRC_CONNECTED when adding an SCG, the SCG can either be suspended or not suspended depending on the configuration.

[0031] In RAN2-108, further discussion was undertaken to clarify the above Further Study Needed (FFS).

[0032] Some solutions were proposed in Rel-16, but these have different problems. For example, in R2-1908679 (Introducing SCG Suspension - Qualcomm), the document proposes that the gNB can instruct the UE to suspend SCG transmission when data traffic is not expected to be sent in the SCG, so that the UE keeps the SCG configuration but does not use the SCG configuration for power saving purposes. Therein, it was mentioned that the signaling to suspend the SCG can be based on DCI / MAC-CE / RRC signaling, but no details on the configuration from the gNB to the UE were provided. Also, different from the specified behavior for the SCell(s), the PSCell(s) may be associated with a different network node, e.g., a gNodeB acting as a secondary node.

[0033] 3GPP discussions on solutions for the Rel-17 MR-DC work item objective "Support efficient activation / de-activation mechanism for one SCG and SCells" have just started in 3GPP RAN1, RAN2 and RAN3. As part of this objective, the concept of "de-activating SCG" is discussed aiming at power saving when traffic demand is dynamically reduced. As also shown in Figure 9, there are two SCG states discussed here called "SCG de-activation state" and "SCG activation state", sometimes referred to as states for SCG activation. These states relate to power saving modes for SCG and should not be confused with RRC states.

[0034] The current RAN2 assumption is that in the "SCG deactivated state", or sometimes called "SCG deactivated", the UE does not perform PDCCH monitoring of the PSCell to save power. This also means that uplink / downlink (UL / DL) data transmission in the SCG is suspended when the SCG is in the SCG deactivated state. SCG activation and deactivation is generally controlled by a network node, for example by the MN using RRC signaling. Moreover, RAN2 agreed that PSCell mobility is supported while the SCG is deactivated, even though the details are still to be further studied (FFS). When a UE is configured with an SCG in the "SCG activated state", the power savings of the SCG do not apply.

[0035] RRC_INACTIVE and suspend / resume procedures: FIG. 10 shows the RRC states in NR as specified in 3GPP TS38.331 v16.2.0.

[0036] When an RRC connection is established, the UE is either in the RRC_CONNECTED state or in the RRC_INACTIVE state, the latter also known as the suspended state. Otherwise, i.e., when an RRC connection is not established, the UE is in the RRC_IDLE state.

[0037] When a UE in RRC_CONNECTED state receives an RRC release with suspend configuration (suspendConfig in RRC release), the UE transitions to RRC_INACTIVE state and stores the configuration in the so-called AS inactive context. Then, when the UE attempts to resume, the configuration is restored so that the network nodes can apply delta signaling in the RRC resume message during the resume procedure.

[0038] Figure 11 shows the RRC procedure for resuming a suspended RRC connection, details of which are specified in 3GPP TS38.331 v16.2.0.

[0039] In certain cases, when an RRC_CONNECTED UE is configured with MR-DC, for example, the RRC_CONNECTED UE has an SCG configured, there are some differences in suspend / resume procedures in 3GPP Release 15 and Release 16.

[0040] The network node may decide to suspend the RRC connection for a UE operating in MR-DC, for example with a secondary cell group (SCG) and a master cell group (MCG) configured, and thus the UE transitions from RRC_CONNETED to RRC_INACTIVE. In Rel-15, it was specified that the UE releases the MR-DC configuration when entering RRC_INACTIVE (although it was rather modeled as MR-DC release at start-up to resume, specified in TS38.331, 5.3.13.2), see Section 5.3.8.3, Receipt of RRC Release by UE, Section 5.3.13, RRC Connection Resume, and Section 5.3.5.10, MR-DC Release, in Rel-15 for more information.

[0041] In Rel-16, an extension is introduced, namely, for a UE operating in MR-DC, e.g. EN-DC, NR-DC, that is suspended and goes RRC_INACTIVE, the UE stores the SCG configuration, at least some of its configuration, so that they can be restored and resumed during the resume procedure. Among the changes introduced in 5.3.8.3, a UE in Rel-16 stores spCellConfigCommon in ReconfigurationWithSync of the NR PSCell (if configured).

[0042] Another change introduced in the resume trigger in Rel-16 for this feature was that if the UE does not support maintaining the SCG configuration on connection resume, the UE only releases the MR-DC, and when the UE restores the context, it restores the MR-DC configuration, including the SCG configuration (as specified up to Rel-16).

[0043] Yet another modification is that RRC RESUME may include the field mrdc-SecondaryCellGroup possibly set to nr-SCG so that SCG RRC reconfiguration may include reconfiguration with synchronization for SCG to be resumed (or added / modified). This is required for the UE to trigger a random access procedure with the PSCell being resumed. For more information, see Section 5.3.8.3 Reception of RRC Release by UE and Section 5.3.13 RRC Connection Resumption with Sections 5.3.13.1 General, 5.3.13.2 Initiation, 5.3.13.3 Actions for sending RRC RESUME REQUEST or RRC RESUME REQUEST 1 message and Section 5.3.13.4 Reception of RRC RESUME by UE in Rel-16.

[0044] As explained above, with the introduction of the SCG power saving mode in 3GPP Rel-17, often referred to in 3GPP as "deactivated SCG" or "SCG deactivated state", the network node may still decide to suspend the UE to RRC_INACTIVE while the SCG is deactivated. If the SCG is activated upon suspension, i.e., upon receipt of an RRC release with suspendConfig, the same behavior may be adopted to some extent as in Rel-16, where the SCG is always activated when the SCG is configured. With the introduction of Rel-17 features, the SCG may be deactivated when the UE receives an RRC release with suspendConfig and transitions to RRC_INACTIVE. It was also agreed that in 3GPP RAN2, when the UE is configured with Multi-Radio Dual Connectivity (MR-DC) including a Master Cell Group (MCG) and a Secondary Cell Group (SCG), whether suspended or not, when the UE resumes from RRC_INACTIVE to RRC_CONNECTED, the SCG state, e.g., SCG Activated or SCG Deactivated, may be set upon RRC Resume. In legacy, when the UE resumes, e.g., due to the fact that there is some uplink traffic, the NAS layer triggers the resume procedure and the cause value mo-Data is set to be included in the RRC Resume Request message as follows:

[0045] 5.3.13 RRC Connection Resumption 5.3.13.1 General TIFF0007681123000001.tif46170 Figure 5.3.13.1-1: RRC connection resumed successfully [...] The purpose of this procedure is to resume an interrupted RRC connection, including resuming the SRB(s) and DRB(s), or to perform an RNA update. [...]

[0046] 5.3.13.2 Startup The UE initiates the procedure when higher layers or the AS request resumption of a suspended RRC connection (when responding to RAN paging, when triggering an RNA update while the UE is in RRC_INACTIVE, or for sidelink communication as specified in subclause 5.3.13.1a).

[0047] The UE shall ensure that it has valid and up-to-date critical system information as specified in clause 5.2.2.2 before initiating this procedure.

[0048] At the start of the procedure the UE shall: 1> If the resumption of the RRC connection is triggered by a response to NG-RAN paging, 2> Select "0" as the access category, 2> Implement the unified access control procedure specified in 5.3.14 using the selected access category and one or more access identities provided by higher layers; 3> If the access attempt is forbidden, the procedure ends, 1> Otherwise, if the resumption of the RRC connection is triggered by higher layers, 2> If the upper layer provides an access category and one or more access identities, 3> Implement the unified access control procedures specified in 5.3.14 using the access categories and access identification information provided by higher layers; 4> If the access attempt is forbidden, the procedure ends, 2> Set resumeCause according to information received from higher layers; [...] RRC Resume Request Message TIFF0007681123000002.tif73170TIFF0007681123000003.tif56170[...] - ResumeCause The IE ResumeCause is used in RRC Resume Request and RRC Resume Request 1 to indicate the resume cause. ResumeCause Information Element TIFF0007681123000004.tif56170

[0049] In the following, the terms "suspended SCG", "SCG in power saving mode", "SCG deactivation state", or "deactivated SCG" are used interchangeably. The term "suspended SCG" may also be referred to as "deactivated or inactive SCG", or "dormant SCG". The terms "resume SCG", "SCG in normal operation mode", "SCG activation state" and "SCG in non-power saving mode" are used interchangeably. The term "resume SCG" may also be referred to as "activated SCG" or "active SCG". The operation of an SCG operating in resumed or active mode may also be referred to as normal SCG operation or legacy SCG operation. An example of the operation is UE signal reception / transmission procedure, e.g., receiving a signal message, transmitting a signal message, etc. The terms "communication device" and "UE" are used interchangeably. The terms "network node", "gNB", "eNB", and "gNodeB" are used interchangeably. Summary of the Invention

[0050] As part of developing the embodiments herein, a problem has been identified and is first described.

[0051] Although upon reception the network node knows that the UE requested the resume procedure due to the need to have a UL transmission, during the UE's RRC resume the network node is not aware whether the UE initiated RRC resume request was triggered by uplink data for MCG DRBs or SCG DRBs. In fact, it remains unknown even after context fetching which allows the network node, e.g. the target network node in case the UE is trying to resume, to know at least whether the UE is configured with SCG or split DRBs.

[0052] This means that the network node will not be aware of which SCG state or operation mode, e.g., SCG activated or SCG deactivated, to select for a UE performing an RRC resumption procedure. Thus, the network node, e.g., the target g Node B where the UE attempts to resume, may unnecessarily activate the SCG if the UL data that triggered the resume request is related to the MCG or the amount of data is not enough to justify activating the SCG. When the network node realizes its suboptimal decision, the network node will have to send another message to the UE after the resume procedure, e.g., RRC reconfiguration and / or MAC CE, to deactivate the SCG for power saving purposes. More power will be consumed during the time the UE is resuming until the time the UE receives this message, and more signaling will be used after the resume. Alternatively, the network node, e.g., the target g Node B where the UE attempts to resume, may deactivate the SCG even though the UE has UL data related to the SCG. In that case, the network node would then have to send another message to activate the SCG after the RRC restart procedure once the network node sees that there is data related to the SCG that justifies activation of the SCG. During the time the UE is restarted until the time the UE receives this message, then performance would be limited by the fact that only the MCG could be used.

[0053] To resume a stored SCG as part of an RRC resumption procedure, i.e. already with or shortly after an RRC resumption message, the network node must do so almost blindly, since it has not then received new measurements on the SCG (PSCell) from the UE that it can use to determine if the UE is in radio coverage of the SCG / PSCell. In that case, there is a risk that the UE will have an SCG configured even if it is out of coverage of the previous SCG / PSCell.

[0054] It is therefore an object of embodiments herein to provide an improved method for handling resume procedures for a communication device operating in dual connectivity involving a Master Cell Group (MCG) and a Secondary Cell Group (SCG) of network nodes in a wireless communication network.

[0055] According to an aspect of an embodiment herein, the objective is achieved by a method implemented in a communication device for handling a resume procedure from a suspended state to a connected state. A multi-radio connectivity (MR-DC) with a master cell group (MCG) and a secondary cell group (SCG) is configured in the communication device. The communication device initiates a resume procedure when there is uplink data available. The communication device determines a type of UL data, i.e., whether the UL data is available for an MCG bearer, an SCG bearer, or a split bearer. The communication device sets a UL data indication based on the determination of whether the UL data is available for an MCG bearer, an SCG bearer, or a split bearer. The communication device sends the UL data indication to a network node. The UL data indication indicates whether the resume is triggered by uplink data available only for the MCG or by uplink data available for the SCG regardless of the data available for the MCG. The UL data indication may be in an information element in the RRC Resume Complete message if not included in a previous message in the resume procedure.

[0056] In other words, the communication device sends a UL data indication to the network node upon resumption from a suspended state, such as an RRC_INACTIVE state, to a connected state, such as an RRC_CONNECTED state, to assist the network node in determining an SCG configuration for the communication device. When UL data is available, resumption from the suspended state is performed and the communication device determines whether the UL data is for an MCG, an SCG, or a split DRB, and sets the UL data indication based on this decision and possibly other criteria, such as a data volume threshold.

[0057] The embodiments herein allow the communication device to explicitly send an indication if there is UL data that needs to be sent via the SCG if one or more bearer types have UL data during the resume procedure. In one embodiment, the communication device checks the bearer types in a given priority order, such as SCG bearers, and split bearers are checked first, so that an indication that the SCG has data to send is triggered first in the procedure. If uplink data is available for the SCG, the communication device sends an indication in a message, for example, an RRC Resume Request message, which may trigger the network node to activate the SCG during the resume procedure. In other cases, the communication device sends an indication that only the MCG side bearers have data to send, which may trigger the network node to not activate the SCG during the resume procedure.

[0058] In another embodiment, a UL data indication for the SCG may be further added in the RRC RESUME COMPLETE message if there is further UL data arrival to be sent via the SCG between sending the RRC RESUME REQUEST message and sending the RRC RESUME COMPLETE message. The network node may activate the SCG in a separate message that is not part of the resume procedure.

[0059] According to an aspect of an embodiment herein, the objective is achieved by a method implemented in a network node, such as a gNB, for determining an SCG configuration when a communication device initiates a resume procedure from a suspended state, such as an RRC_INACTIVE state, to a connected state, such as an RRC_CONNECTED state, based on an UL data indication, an SCG coverage indication or a measurement report received from the communication device. The network node comprises: determining whether a suspended SCG should be resumed and, if so, which operation mode, e.g. deactivated or activated, should be set for the SCG; If an SCG is established on the communications device attempting to resume, determining whether the SCG should be released; If an SCG is not set on the communication device attempting to resume, determining whether an SCG should be added and, if an SCG should be added, what operating mode, e.g., deactivated or activated, should be set for the SCG. The following is set:

[0060] According to one aspect of an embodiment of the present specification, the objective is achieved by a method implemented in a communication device in an RRC_INACTIVE state for initiating measurements on an SCG, e.g., a PSCell, that the communication device has stored as part of a UE inactive AS context, when the communication device determines that it has UL data available for an SCG, such as an SCG DRB, or a sufficient amount of data available for a split DRB to justify SCG activation.

[0061] Embodiments herein enable a network node to select a strategy for a communication device in MR-DC during resumption from a suspended state to select an SCG state, for example an SCG deactivated state or an SCG activated state.

[0062] In some embodiments, an advantage of the embodiments herein is that the network node may set the SCG state in a first RRC message, such as an RRC Resume RRC message responding to a resume request.

[0063] For the methods according to the embodiments herein, a network node, e.g. a target network node where a communication device is attempting to resume, is made aware whether the communication device initiated RRC resume request was triggered by uplink data for an MCG DRB or by uplink data for an SCG DRB, and based thereon makes an appropriate informed decision regarding setting up an MR-DC, releasing MR-DC, resuming MR-DC, and in the case of setup and resume, in which state or operating mode the SCG should be, e.g. a deactivated SCG or an activated SCG.

[0064] According to the embodiments of the present specification, the network node may also select a strategy for a communication device in MR-DC when resuming when more than one type of DRB has uplink data to transmit, and the DRB type may be MCG DRB, SCG DRB or split DRB. One example is that both MCG DRB and SCG DRB have uplink data to transmit.

[0065] Thus, a network node, e.g., a target gNodeB where a communication device attempts to resume, will not activate the SCG unnecessarily if the UL data that triggered the resume request is related to the MCG or the amount of data is not sufficient to justify activating the SCG, which prevents unnecessary actions on the SCG and prevents unnecessary waste of energy in the communication device, which leads to lower power consumption in the communication device due to the methods according to the embodiments herein.

[0066] In addition, by preventing a potentially sub-optimal decision, the network node does not need to send a separate message to the communication device after a resumption procedure, e.g. RRC reconfiguration and / or MAC CE, to deactivate the SCG for power saving purposes, which is also a signaling reduction.

[0067] Accordingly, embodiments herein provide an improved method for handling resume procedures for a communication device operating in dual connectivity involving a master cell group (MCG) and a secondary cell group (SCG) of network nodes in a wireless communication network.

[0068] Example embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. [Brief description of the drawings]

[0069] [Figure 1] FIG. 1 is a schematic block diagram showing dual connectivity combined with carrier aggregation in MR-DC. [Diagram 2] FIG. 1 is a schematic block diagram showing E-UTRAN-NR dual connectivity. [Diagram 3] FIG. 1 is a schematic block diagram showing NR-DC, in which both the master node controlling the MCG and the secondary node controlling the SCG are NR. [Figure 4] FIG. 1 is a schematic block diagram illustrating a control plane architecture for dual connectivity in LTE DC, EN-DC and NR-DC. [Diagram 5] A schematic block diagram showing network side protocol termination options for MCG, SCG and split DRB in MR-DC (EN-DC) with EPC. [Figure 6] A schematic block diagram showing network side protocol termination options for MCG, SCG and split DRB in MR-DC (NGEN-DC, NE-DC and NR-DC) with 5GC. [Figure 7] FIG. 2 is a schematic block diagram illustrating packet duplication. [Figure 8] FIG. 1 is a schematic block diagram illustrating pause-like behavior for SCells in NR. [Figure 9]FIG. 1 is a schematic block diagram showing the SCG state in 3GPP Rel-17. [Figure 10] FIG. 1 is a schematic block diagram showing a UE state machine and state transitions in NR. [Figure 11] A signaling diagram showing the RRC connection resumption procedure, successful case. [Figure 12] 1 is a schematic block diagram illustrating a wireless communication network. [Figure 13] 1 is a flow chart illustrating an exemplary embodiment of a method implemented in a communication device, according to embodiments herein. [Figure 14] FIG. 1 is a signaling diagram illustrating an example embodiment of a resume procedure, according to embodiments herein. [Figure 15] FIG. 11 is a signaling diagram illustrating another exemplary embodiment of a restart procedure, according to embodiments herein. [Figure 16] FIG. 11 is a signaling diagram illustrating another exemplary embodiment of a restart procedure, according to embodiments herein. [Figure 17] 11 is a flow chart illustrating another exemplary embodiment of a method implemented in a communication device, according to embodiments herein. [Figure 18] 1 is a flow chart illustrating an example embodiment of a method implemented in a network node, according to embodiments herein. [Figure 19] 11 is a flow chart illustrating another exemplary embodiment of a method implemented in a network node, according to embodiments herein. [Figure 20] FIG. 2 is a schematic block diagram illustrating an exemplary embodiment of a network node. [Figure 21] 1 is a schematic block diagram illustrating an exemplary embodiment of a communication device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0070] 12 is an overview of a communication network 1200. The communication network 1200 may be a wireless communication network including one or more RANs and one or more CNs. The communication network 1200 may use several different technologies, such as Wi-Fi, Long Term Evolution (LTE), LTE-Advanced, NR, Wideband Code Division Multiple Access (WCDMA), Global System for Mobile Communications / Advanced Data Rates for Global System for Mobile Communications Evolution (GSM / EDGE), Worldwide Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), to name just a few possible implementations.

[0071] In the wireless communication network 1200, one or more wireless communication devices 1230, 1231, such as UEs, mobile stations or wireless terminals, communicate through one or more radio access networks (RANs) to one or more core networks (CNs). It should be understood by those skilled in the art that a "wireless communication device" is a non-limiting term meaning any terminal, wireless communication terminal, user equipment, machine type communication (MTC) device, D2D (Device to Device) terminal, or node, such as a smartphone, laptop computer, mobile phone, sensor, relay, mobile tablet, or even a small base station, that communicates within a cell.

[0072] Network nodes such as a first network node 1211 and a second network node 1212 operate in the wireless communication network 1200. The first network node 1211 and the second network node 1212 may be any of RAN nodes, such as gNB, eNB, en-gNB, ng-eNB, gNB, etc. The first network node 1211 provides wireless coverage over a geographical area, service area 11, sometimes referred to as a beam, or beam group, where a group of beams covers a service area of ​​a first radio access technology (RAT), such as 5G, LTE, Wi-Fi, or the like. The second network node 1212 provides wireless coverage over a geographical area, service area 12, sometimes referred to as a beam, or beam group, where a group of beams covers a service area of ​​a first or second radio access technology (RAT), such as 5G, LTE, Wi-Fi, or the like. It should be noted that the network nodes may be RAN nodes, CN nodes, or OAM nodes.

[0073] The first network node 1211 and the second network node 1212 may be transmitting and receiving points, e.g. wireless network access nodes such as wireless local area network (WLAN) access points or access point stations (AP STAs), access controllers, base stations, e.g. radio base stations such as Node B, gNB, evolved Node B (eNB, eNode B), base transceiver stations, wireless remote units, access point base stations, base station routers, radio base station transmission arrangements, standalone access points, or any other network units capable of communicating with wireless communication devices within a service area served by the respective first network node 1211 and second network node 1212, e.g. depending on the radio access technology and terminology used. The first network node 1211 and the second network node 1212 may be referred to as a source network node and a target network node, respectively, and may communicate with the wireless communication devices 1230, 1231 using downlink (DL) transmissions to the wireless communication devices 1230, 1231 and uplink (UL) transmissions from the wireless communication devices 1230, 1231.

[0074] The first network node 1211 and the second network node 1212 may each be either a master node (MN) having a cell group MCG or a secondary node (SN) having a cell group SCG, respectively, as shown in FIG. 1.

[0075] The description herein describes terms such as SCG and PSCell as one of the cells associated with the SCG, which may be, for example, a PSCell defined in the NR specifications (e.g., RRC TS38.331) as a special cell (SpCell) or a primary SCG cell (PSCell) of the SCG, as follows: - Secondary cell group: For a UE configured with dual connectivity, a subset of serving cells including a PSCell and zero or more secondary cells (SCells). - Special cell: In the case of dual connectivity operation, the term special cell refers to a PCell of an MCG or a PSCell of an SCG, and in other cases, the term special cell refers to a PCell. - Primary SCG Cell (PSCell): In case of dual connectivity operation, this is the SCG cell to which the UE performs random access when performing a reconfiguration procedure with synchronization.

[0076] For brevity, the description herein mostly refers to and illustrates examples where the second cell group is a secondary cell group (SCG) that is deactivated or suspended or in a power saving mode of operation for a UE configured with multi-radio dual connectivity (MR-DC). However, the method is equally applicable when the second cell group is a master cell group (MCG) for a UE configured with dual connectivity (e.g., MR-DC) and the MCG may be suspended while the SCG operates in normal mode.

[0077] The description herein describes that when the second cell group is deactivated, e.g., the SCG is deactivated upon receiving an instruction from a network node, the UE stops monitoring the PDCCH on the SCG cells, i.e., stops monitoring the PDCCH of the PSCell and of the SCell of the SCG. The solution is mainly described using the second cell group as an example, which is a secondary cell group configured in the UE with MR-DC configured, and is an SCG that is in a deactivated operation mode in the UE when the UE performs the actions disclosed in the method. However, the method is also applicable when assuming that the second cell group is a deactivated master cell group (MCG), such that the UE stops monitoring the PDCCH on the MCG and continues to monitor the PDCCH on the SCG.

[0078] Correspondingly, the description herein refers mostly to and illustrates examples in which the first cell group is a Master Cell Group (MCG) for a UE configured with Multi-Radio Dual Connectivity (MR-DC). However, the method is equally applicable when the first cell group is a Secondary Cell Group (SCG) for a UE configured with Multi-Radio Dual Connectivity (MR-DC) that is deactivated or suspended or in a power saving mode of operation.

[0079] According to embodiments herein, a method is provided, implemented by a communications device 1230, for handling a resume procedure from a first state to a second state. The first state may be a suspended state, such as an RRC_INACTIVE state, and the second state may be a connected state, such as an RRC_CONNECTED state.

[0080] According to embodiments herein, the communications device 1230 determines whether the resume procedure is triggered by uplink data available for the MCG, such as an MCG DRB, by uplink data available for the SCG, such as an SCG DRB, or whether a sufficient amount of data is available for the split DRBs, e.g., determined based on a configured threshold for UL data volume, to justify SCG activation. Based on this determination, the communications device 1230 includes a UL data indication during the resume procedure, e.g., in and / or multiplexed with a resume request to the network node 1211.

[0081] In the first embodiment, the communication device 1230 checks data availability in the following priority order: SCG bearer, split bearer, and then MCG bearer. In other words, the communication device 1230 first checks whether there is available UL data in the SCG bearer, followed by the split bearer and MCG bearer.

[0082] The method according to the first embodiment will be described in detail with reference to Fig. 13, in which the main actions or steps performed by the communication device 1230 are shown. The method includes the following actions, which may be performed in any suitable order:

[0083] Action 13010 The communication device 1230 is in a first state, e.g., a suspended state, such as an RRC_INACTIVE state, and has an MR-DC with an MCG and an SCG configured. When uplink data becomes available, higher layers trigger the RRC layer to initiate a resumption of the suspended RRC connection at the communication device 1230.

[0084] Action 13020 The communication device 1230 checks whether the SCG bearer has data. If the SCG bearer has data, the communication device 1230 sets the UL data indication to "SCG" at action 13060.

[0085] Action 13030 If the SCG bearer does not have data, the communication device 1230 checks whether the split bearer has data. If the split bearer does not have data, the communication device 1230 sets the UL data indication to "MCG" at action 13050.

[0086] Action 13040 If the split bearer has data, the communication device 1230 checks whether the total amount of data, e.g., PDCP data volume and RLC data volume pending for initial transmission in the primary and split secondary RLC entities for the split bearer, exceeds a threshold, e.g., ul-DataSplitThreshold. If the data exceeds the threshold, the communication device 1230 sets the UL data indication to "SCG" at action 13060. Otherwise, the communication device 1230 sets the UL data indication to "MCG" at action 13050.

[0087] Action 13050 The communication device 1230 sets the UL data indication to "MCG."

[0088] Action 13060 The communication device 1230 sets the UL data indication to "SCG."

[0089] Action 13070 The communications device 1230 initiates the resume procedure by sending a resume request, e.g., an RRC resume request message, to a network node, e.g., network node 1211. During the resume procedure, the communications device 1230 also sends a UL data indication set according to a previous action.

[0090] In this embodiment, if the UL data indication is set to SCG, then either the SCG bearer has data or the split bearer has more data than a threshold, and therefore an indication from the communication device 1230 that there is data available for the SCG, although it is not clear whether there is data available for the MCG. However, this is not required, since the MCG needs to be resumed in either case.

[0091] When the UL data indication is set to MCG, neither the SCG bearer has data nor the split bearer has more data than the threshold, and therefore this is an implicit indication from the communication device 1230 that there is no data available for the SCG.

[0092] In one alternative, in action 13020 of FIG. 13, the criterion for when an SCG bearer has data is that the amount of data for the SCG bearer, e.g., the PDCP data volume and the RLC data volume pending for initial transmission in the RLC entity, or only the PDCP data volume, exceeds a threshold. In another alternative, the communication device 1230 calculates the sum of the amount of data for all MCG bearers, which is referred to herein as MCG_SUM, and also calculates the sum for all SCG bearers, which is referred to herein as SCG_SUM. The communication device 1230 then compares MCG_SUM to SCG_SUM to determine whether the SCG bearer has data. For example, if SCG_SUM is greater than MCG_SUM, the SCG bearer is determined to have data. Or for example, if SCG_SUM is greater than MCG_SUM+threshold, the SCG bearer is determined to have data. The threshold in these alternatives may be set by the network node 1211.

[0093] In yet another alternative, in action 13040 of FIG. 13, the threshold criteria for the split bearer is compared to the amount of data volume in the MCG bearer. The communication device 1230 calculates the sum of the amount of data for all MCG bearers (MCG_SUM) and the sum of the amount of data for all split bearers (SPLIT_BEARER_SUM). Examples include if SPLIT_BEARER_SUM exceeds MCG_BEAER_SUM or MCG_BEARER_SUM+threshold, the split bearer is determined to have data. The thresholds in these alternatives may be set by the network node 1211.

[0094] The communications device 1230 may include a UL data indication during the resumption procedure, for example within and / or multiplexed with the resume request to the network node 1211.

[0095] There may be different alternatives regarding how the UL data indication is indicated to the network node 1211.

[0096] In one alternative, as shown in Fig. 14, during the resume procedure, the UL data indication may be sent, for example, as a resume cause, which may be a parameter set in the RRC resume request message that the UE sends to the network node MN / gNB that the UE is attempting to resume. For example, a new resume cause, e.g., scg-data, is set to indicate that the resume procedure is triggered by a certain amount of data mapped to an SCG bearer or split bearer exceeding a predefined threshold. And in other cases, e.g., when the UL data is for an MCG bearer, the UE sets the value of the existing resume cause "mo-data" or another existing resume cause. In another embodiment, the new cause value may indicate that the UE has an amount of UL data in the buffer that exceeds a certain threshold, regardless of whether it is associated with an SCG bearer.

[0097] An example of how this is implemented in the 3GPP specification is shown below with the changes underlined:

[0098] PDCP Specification v16.2.0 ******************************************************************************************************** 5.6 Data volume calculation -----Unchanged parts omitted----- If a transmitting PDCP entity is associated with at least two RLC entities, when indicating the PDCP data volume to the MAC entity for BSR triggering and buffer size calculation (as specified in TS 38.321[4] and TS 36.321

[12] ), the transmitting PDCP entity shall do the following: - if PDCP replication is activated for a RB, - indicating the PDCP data volume to a MAC entity associated with the primary RLC entity; - indicating the PDCP data volume, excluding PDCP control PDUs, to the MAC entities associated with RLC entities other than the primary RLC entity activated for PDCP replication; - indicating the MAC entity associated with the deactivated RLC entity for PDCP replication with a PDCP data volume of 0; - otherwise (i.e. PDCP replication has been deactivated for the RB), - if a split secondary RLC entity is configured, and - if the sum of the PDCP data volume and the RLC data volume pending for initial transmission (as specified in TS 38.322 [5]) in the primary RLC entity and in the split secondary RLC entity is equal to or greater than ul-DataSplitThreshold, - indicating the PDCP data volume to both the MAC entity associated with the primary RLC entity and the MAC entity associated with the split secondary RLC entity; - indicating the PDCP data volume as 0 to the MAC entities associated with RLC entities other than the primary RLC entity and the split secondary RLC entity; - otherwise, if the transmitting PDCP entity is associated with a DAPS bearer, - if no uplink data switching was requested, - indicating the PDCP data volume to the MAC entity associated with the source cell; - In other cases, - indicating to a MAC entity associated with the target cell a PDCP data volume excluding PDCP control PDUs for interspersed ROHC feedback associated with the source cell; - indicating to a MAC entity associated with the source cell the PDCP data volume of PDCP control PDUs for interspersed ROHC feedback associated with the source cell; - In other cases, - indicating the PDCP data volume to a MAC entity associated with the primary RLC entity; - Indicate the PDCP data volume as 0 to the MAC entities associated with RLC entities other than the primary RLC entity. 2> Indicate to the RRC layer which RLC entities that have a non-zero PDCP data volume to transmit according to the procedure in this subclause. ********************************************************************************************************* RRC Specification v16.3.0 *********************************************************************************************************

[0099] 5.3.13.2 Startup -----Unchanged parts omitted----- At the start of the procedure the UE shall: 1> If the resumption of the RRC connection is triggered by a response to NG-RAN paging, -----Unchanged parts omitted----- 1> Otherwise, if the resumption of the RRC connection is triggered by higher layers, -----Unchanged parts omitted----- 1> Otherwise, if the resumption of the RRC connection is triggered by an RNA update as specified in 5.3.13.8, -----Unchanged parts omitted----- 1> Otherwise, if the SCG is deactivated, 2> If the resumption of the RRC connection is triggered by an RLC entity associated with the SCG, 3> Set resumeCause to "scg-data", 2> Otherwise, if the resumption of the RRC connection is triggered by an RLC entity associated with the MCG, 3> Set resumeCause to "mo-data", 1> If the UE is in NE-DC or NR-DC, ... ************************************************************************************************

[0100] In another embodiment, as shown in Fig. 15, the UL data indication is indicated to the network node, for example by selection of a specific PRACH resource, such as a preamble, and / or a specific time-frequency PRACH resource, which may be associated with a preamble group, indicating the UL data indication according to a random access configuration, to the MN / gNB where the UE is attempting to resume. For example, the network node may have configured a preamble group for indicating UL traffic above a threshold, and thus the UE wishing to resume determines whether the UL data in the buffer exceeds the threshold, and if so, the UE selects a preamble associated with that group such that upon reception at the network node, the network node notices that the UE has an amount of UL data in the buffer that exceeds the threshold. In one alternative, the UL data indication is related to data to be transmitted by the SCG, for example data mapped to an SCG bearer, and thus the UL data indication indicates to the network node not only that the amount of data exceeds a threshold, but also that the amount of data is for SCG transmission. Another alternative is to define multiple preamble groups indicating different indications, e.g., group X1 data for both MCG and SCG, group X2 data for SCG only, group X3 data for MCG only. In one example, the network node provides configuration for PRACH resource(s), e.g., preamble(s) and / or specific time-frequency PRACH resource(s), to use for UL data indication in the system information. In another example, the network node provides configuration in dedicated signaling, such as an RRC release message that suspends the UE to RRC_INACTIVE state.

[0101] In another embodiment, as shown in FIG. 16, UL data on the SCG may further be indicated in the RRC Resume Complete message. This is useful when there is data arrival for the SCG after the RRC Resume Request is sent. This is implemented with the communication device 1230 embodiment in the first embodiment described above. If the communication device 1230 indicated the UL data as "scg-data" in the RRC Resume Request message, the communication device 1230 does not indicate anything more in the RRC Complete message. If the communication device 1230 did not indicate the UL data as "scg-data" in the RRC Request message and there is data available in the RLC entity related to the SCG that needs to be transmitted after receiving the RRC Resume message from the network node, the communication device 1230 indicates in the RRC Complete message that there is data available in the RLC entity related to the SCG.

[0102] Below is an example of how this could be implemented in the RRC specification v16.3.0, with the changes underlined: *********************************************************************************************************

[0103] 5.3.13.4 UE Reception of RRC Resumption The UE shall: -----Unchanged parts omitted----- 1> Set the content of the RRC resume complete message as follows: -----Unchanged parts omitted----- 2> If the UE is configured to provide measurement gap requirement information for the NR target band, 3> Include NeedForGapsInfoNR and set the content as follows: 4> Set intra-frequency measurement gap requirement information for each NR serving cell, including intraFreq-needForGap; 4>For each supported NR band that is also included in requestedTargetBandFilterNR, if requestedTargetBandFilterNR is set, include an entry in interFreq-needForGap for that band and set the gap requirement information, otherwise, for each supported NR band, include an entry in interFreq-needForGap and set the corresponding gap requirement information; 2> If the RRC resume message contains activateSCG and resumeCause is not set to "scg-data", 3> When the PDCP layer indicates the data volume of the RLC entity associated with the SCG, 4> Include the UL data indicator scg-Data and set it to true. 1> submit an RRC resume complete message to lower layers for transmission; 1> The procedure ends. ... - RRC restart completed The RRC resume complete message is used to confirm successful completion of the RRC connection resume. Signaling Radio Bearer: SRB1 RLC-SAP:AM Logical channel: DCCH Direction: UE to network RRC Resume Complete Message TIFF0007681123000005.tif112170****************************************************************************************************************

[0104] According to a second embodiment herein, a method implemented by a communication device 1230 is provided for handling a resume procedure from a first state, e.g., a suspended state, to a second state, e.g., a connected state, which may be combined with the first embodiment described above. The communication device 1230 in RRC_INACTIVE initiates measurements on an SCG, e.g., a PSCell, that the communication device 1230 stored as part of the UE inactive AS context when the communication device 1230 determines that the communication device 1230 has UL data available for an SCG, such as UL data available for an SCG DRB, or a sufficient amount of data available for a split DRB to justify SCG activation.

[0105] The method will be described in detail with reference to Fig. 17, in which the main actions or steps performed by the communication device 1230 according to the second embodiment are shown. The method includes the following actions, which may be performed in any suitable order:

[0106] Action 17010 The communication device 1230 is in a suspended state, such as an RRC_INACTIVE state, and has an MR-DC with an MCG and an SCG configured. Uplink data becomes available and higher layers trigger the RRC layer to initiate a resumption of the suspended RRC connection at the communication device 1230.

[0107] Action 17020 The communication device 1230 checks whether the SCG bearer has data. If the SCG bearer has data, the communication device 1230 initiates measurement on the SCG at action 17050.

[0108] Action 17030 If the SCG bearer does not have data, the communication device 1230 checks whether the split bearer has data.

[0109] Action 17040 If the split bearer has data, the communication device 1230 checks whether the total amount of data, i.e., the PDCP data volume and the RLC data volume pending for initial transmission in the primary and split secondary RLC entities for the split bearer, exceeds a threshold, e.g., ul-DataSplitThreshold. If the data exceeds the threshold, the communication device 1230 initiates measurements on the SCG at action 17050.

[0110] Action 17050 The communications device 1230 initiates measurements on the SCG.

[0111] In one alternative, the communication device 1230 performs continuous measurements on a suspended SCG, e.g., a PSCell, while the communication device 1230 is in an RRC_INACTIVE state. In one example, the communication device 1230 performs measurements on a suspended SCG (PSCell), i.e., an SCG stored in the UE inactive AS context, while in an RRC_INACTIVE state based on a network configuration. The network configuration may then be provided, for example, through system information, whereby the network configuration is valid, for example, in the cell in which it is broadcast, or may be provided through dedicated signaling, for example, in an RRC release message that suspended the communication device 1230 and put it in the RRC_INACTIVE state.

[0112] In another alternative, the communication device 1230 in the RRC_INACTIVE state initiates measurements for a suspended SCG, e.g., a PSCell, that the communication device 1230 stored as part of the UE inactive AS context when the communication device 1230 determines that the communication device 1230 has an amount of UL data available for split DRBs that exceeds a threshold. The threshold may then be set by the network, e.g., in the system information or in dedicated signaling, e.g., in the RRC release message that suspended the communication device 1230 to the RRC_INACTIVE state. In one example, the threshold for initiating measurements for a suspended SCG / PSCell is then lower than the threshold for indicating that the SCG should be activated and / or resumed.

[0113] In some alternatives to the above embodiments, the communication device 1230 indicates to the network node whether the communication device 1230 is in coverage of the suspended SCG, e.g., PSCell, as part of or following the RRC restart procedure. The communication device 1230 may then indicate to the network node whether the communication device 1230 is in coverage of the suspended SCG / PSCell, e.g., through an SCG in-coverage indication. In one example, the communication device 1230 determines that the communication device 1230 is in coverage of the suspended SCG, e.g., PSCell, based on one or more thresholds, e.g., based on a measured Reference Signal Received Power (RSRP) value, Reference Signal Received Quality (RSRQ) value, and / or a Signal to Interference Plus Noise Ratio (SINR) value for the suspended PSCell being above a configured threshold(s). The threshold for determining whether the communication device 1230 is in the coverage of a suspended SCG, e.g., a PSCell, may be based on a network configuration that may be provided to the communication device 1230 by the network nodes 1211, 1212, for example, through system information or through dedicated signaling, such as, for example, in an RRC release message that suspended the communication device 1230 and placed it in an RRC_INACTIVE state.

[0114] In one alternative, the UE transmits measurement results, e.g., measured RSRP values, RSRQ values ​​and / or SINR values, for an SCG, e.g., a PSCell, that were stored as part of the UE inactive AS context while the communication device 1230 was in the RRC_INACTIVE state during or following the RRC resumption procedure.

[0115] In some alternatives, an indication of whether the UE is in coverage of the suspended SCG / PSCell, i.e., an SCG in coverage indication and / or measurement results for the suspended SCG / PSCell, is provided by the communication device 1230 to the network node together with the UL data indication according to the above embodiments. In some alternatives, the SCG in coverage indication and / or measurement results for the suspended SCG / PSCell are provided by the communication device 1230 to the network node according to those methods even if a UL data indication is not provided to the network node. In one example, the SCG in coverage indication and / or measurement results for the suspended SCG / PSCell are provided within or multiplexed with the RRC Resume Request message, e.g., as one or more separate fields or using a specific resume cause value. In another example, the SCG in-coverage indication and / or measurement results for the suspended SCG / PSCell are provided within the RRC Restart Complete message or in another RRC message, such as a UE Assistance Information message, sent as part of or after the RRC Restart procedure.

[0116] According to an embodiment herein, a method is provided, implemented by network nodes 1211, 1212, for handling a resume procedure for a communication device 1230 in a wireless communication network 1200.

[0117] According to a first embodiment, the network nodes 1211, 1212 act as target network nodes, e.g. gNode B, to which the communication device 1230 is attempting to resume. The method includes receiving a UL data indication, e.g. as described above, related to a suspended SCG from the communication device 1230 and determining based on that information an SCG configuration for the communication device 1230, which may be referred to as an MR-DC strategy to be set for the terminating communication device 1230.

[0118] The method will now be described in detail with reference to Figure 18, in which the main actions or steps performed by a network node according to a first embodiment are shown. The method comprises the following actions, which may be performed in any suitable order:

[0119] Action 18010 The network nodes 1211 , 1212 receive a UL data indication from the communication device 1230 during a resumption procedure initiated by the communication device 1230 .

[0120] Action 18020 The network nodes 1211, 1212 determine the SCG configuration for the communication device 1230 based on the received UL data indication.

[0121] Action 18030 The network nodes 1211, 1212 configure the communication device 1230 according to the determined SCG configuration, which may be provided in a message sent to the communication device 1230, for example in an RRC Restart message in response to an RRC Restart request or in a separate RRC Reconfiguration message.

[0122] As part of determining the SCG settings for the communication device 1230, the network nodes 1211, 1212 perform at least one of the following actions: determining whether a suspended SCG should be resumed and, if so, which operation mode, e.g. deactivated or activated, should be set for the SCG; If an SCG is established for the UE attempting to resume, determining whether the SCG should be released; If no SCG is configured for the UE attempting to resume, determine whether an SCG should be added, and if an SCG should be added, which operation mode, e.g., deactivated or activated, should be set for the SCG.

[0123] The method comprises the network node determining an MR-DC strategy based on the UL data indication and possibly other information, such as resource availability for the SCG, possibly indicated by the SN, or measurement results from the communication device 1230, e.g., RSRP, RSRQ, SINR from the communication device 1230 for the PSCell(s) and / or SCells of the SCG, which may have been obtained as early measurement reports.

[0124] According to a second embodiment, the target network node, e.g. the network node 1211, 1212 acting as a gNodeB where the UE is attempting to resume, receives from the communication device 1230, as part of the RRC resume procedure, an indication that the communication device 1230 is in coverage of an SCG / PSCell stored as part of the UE inactive AS context, e.g. an SCG in coverage indication. Based on this indication, the network node 1211, 1212 may decide whether to restore the suspended SCG, e.g. a PSCell. The indication may also be used by the network node 1211, 1212 to decide whether to resume the SCG / PSCell in an SCG activated or SCG deactivated state. As an example, if the SCG in coverage indication indicates that the communication device 1230 is not in coverage of an SCG, e.g., a PSCell, the network node 1211, 1222 does not resume the SCG, or the network node 1211, 1222 resumes the SCG in a deactivated state, i.e., in an SCG power saving mode.

[0125] The network nodes 1211, 1212 may also receive measurement reports from the communication device 1230 and use the content of the reports in determining the SCG configuration.

[0126] The method will now be described in detail with reference to Figure 19, in which the main actions or steps performed by a network node according to the second embodiment are shown. The method comprises the following actions, which may be performed in any suitable order:

[0127] Action 19010 The network nodes 1211 , 1212 receive an SCG coverage indication from the communication device 1230 during a resumption procedure initiated by the communication device 1230 .

[0128] Action 19020 The network nodes 1211, 1212 determine the SCG settings for the communication device 1230 based on the received SCG coverage indication.

[0129] Action 19030 The network nodes 1211, 1212 configure the communication device 1230 according to the determined SCG configuration, which may be provided in a message sent to the communication device 1230, for example in an RRC Restart message in response to an RRC Restart request or in a separate RRC Reconfiguration message.

[0130] To implement the method in the network nodes 1211, 1212, the network nodes 1211, 1212 comprise the modules shown in Figure 20. The network nodes 1211, 1212 comprise a receiving module 2010, a sending module 2020, a determining module 2030, a processing module 2040, a memory 2050, etc.

[0131] The network nodes 1211, 1212 are configured to perform any one of the actions 18010-18030, 19010-19030 described above.

[0132] The methods according to the embodiments herein may be implemented through one or more processors, such as the processor 2060 in the network nodes 1211, 1212, with computer program code for performing the functions and actions of the embodiments herein. The above-mentioned program code may also be provided as a computer program product, for example in the form of a computer readable medium or data carrier 2080, which, when loaded into the network nodes 1211, 1212, carries the computer program code 2070 shown in FIG. 11 for performing the embodiments herein. One such carrier may be in the form of a CD ROM disk. However, such a carrier may be realizable on other data carriers, such as a memory stick. The computer program code may further be provided as pure program code on a server or cloud and downloaded to the network nodes 1211, 1212.

[0133] 21 illustrates an exemplary embodiment for a communication device 1230 in which a method for handling a resume procedure may be implemented. The communication device 1230 comprises the modules illustrated in FIG. 21. The communication device 1230 comprises a receiving module 2110, a transmitting module 2120, a determining module 2130, a processing module 2140, a memory 2150, etc. The communication device 1230 is configured to perform any one of the method actions 13010-13070, 17010-17050 described above.

[0134] The methods according to the embodiments herein may be implemented through one or more processors, such as the processor 2160 in the UE 1230, with computer program code for performing the functions and actions of the embodiments herein. The above-mentioned program code may also be provided as a computer program product, for example in the form of a computer readable medium or data carrier 2180, which, when loaded into the UE 1230, carries the computer program code 2170 shown in FIG. 21 for performing the embodiments herein. One such carrier may be in the form of a CD ROM disk. However, such a carrier may be realizable on other data carriers, such as a memory stick. The computer program code may further be provided as pure program code on a server or cloud and downloaded to the communication device 1230.

[0135] Several exemplary embodiments are described below. Embodiment 1: A method implemented by a communication device 1230 operating in dual connectivity with a master cell group (MCG) and a secondary cell group (SCG) of network nodes 1211, 1212 in a wireless communication network 1200 for handling a resume procedure from a first state, e.g., a suspended state, to a second state, e.g., a connected state, the network nodes 1211, 1212 being target network nodes to which the communication device 1230 should resume a connection, the method comprising: initiating a restart procedure; sending an uplink (UL) data indication to the network nodes 1211, 1212; A method comprising:

[0136] Embodiment 2: The method of embodiment 1, further including determining a type of data radio bearer for the UL data, such as whether the UL data is available for an MCG bearer, an SCG bearer, or a split bearer.

[0137] Embodiment 3: The method of embodiment 1 or 2, in which the UL data indication indicates whether the resumption is triggered by uplink data that is available only for the MCG or whether uplink data is available for the SCG regardless of the data available for the MCG.

[0138]

[0023] Embodiment 4: The method of any one of embodiments 1 to 3, further comprising setting a UL data indication based on the determined type of the UL data.

[0139] Embodiment 5: The method according to any one of embodiments 1 to 4, wherein the UL data indication is an information element in an RRC resume complete message if not included in a previous message in the resume procedure.

[0140] Embodiment 6: A method implemented by a communication device 1230 operating in dual connectivity with a master cell group (MCG) and a secondary cell group (SCG) of a network node 1211, 1212 in a wireless communication network 1200 for performing measurements on an SCG, the communication device 1230 being in a suspended state, the method comprising: Determining when UL data will be available; To carry out measurements on SCG A method comprising:

[0141] Embodiment 7: The method of embodiment 6, further including determining a type of UL data, i.e., whether the UL data is available for an MCG bearer, an SCG bearer, or a split bearer.

[0142] Embodiment 8: The method of embodiment 6 or 7, wherein performing the measurement is based on a determined type of UL data.

[0143] Embodiment 9: The method of any one of embodiments 6 to 8, wherein performing the measurement includes one of starting the measurement, continuing the measurement, or stopping the measurement.

[0144]

[0023] Embodiment 10: The method according to any one of embodiments 6 to 9, further comprising sending an SCG coverage indication to a network node.

[0145]

[0036] Embodiment 11: The method of any one of embodiments 6 to 10, further comprising transmitting the measurement report to the network node.

[0146] Embodiment 12: A method implemented by a network node 1211, 1212 for handling a resume procedure for a communication device 1230, the communication device 1230 operating in dual connectivity with a master cell group (MCG) and a secondary cell group (SCG) of the network node, and should request resume from a first state, e.g., a suspended state, to a second state, e.g., a connected state, the method comprising: receiving a request to resume from a communication device 1230; receiving a UL data indication from the communication device 1230; determining an SCG setting for the communication device 1230 based on the UL data indication; Configuring the communication device 1230 according to the determined SCG configuration. A method comprising:

[0147] Embodiment 13: A method implemented by a network node 1211, 1212 for handling a resume procedure for a communication device 1230, the communication device 1230 operating in dual connectivity with a master cell group (MCG) and a secondary cell group (SCG) of the network node, and should request resume from a first state, e.g., a suspended state, to a second state, e.g., a connected state, the method comprising: receiving a request to resume from a communication device 1230; receiving an SCG coverage indication from a communication device 1230; Determining an SCG setting of the communication device 1230; Configuring the communication device 1230 according to the determined SCG configuration. A method comprising:

[0148] Embodiment 14: The method of embodiment 13, wherein determining the SCG setting of the communication device 1230 is based on an SCG coverage indication.

[0149] Embodiment 15: The method of embodiment 13, further comprising receiving a measurement report from the communication device 1230, and determining the SCG configuration is based on the measurement report.

[0150]

[0081] Embodiment 16: Determining the SCG setting of the communication device 1230 includes: - determining whether a suspended SCG should be resumed and, if so, which operation mode, e.g. deactivated or activated, should be set for the SCG; - if an SCG is configured on the communications device 1230 that is attempting to resume, determining whether the SCG should be released; - if no SCG is set for the communication device 1230 attempting to resume, determining whether an SCG should be added and, if so, what operation mode, e.g., deactivated or activated, should be set for the SCG; 16. The method of any one of embodiments 13 to 15, including any one of the following:

Claims

1. 12. A method implemented in a communications device in association with a resume procedure from a power saving mode of operation to a connected mode of operation, the method comprising: configuring the communications device with a multi-radio dual connectivity (MR-DC) with a first group of cells and a second group of cells in a wireless communications network, the method comprising: Initiating a resume procedure when there is uplink (UL) data available at the communication device (1230) while the communication device (1230) is in the power saving mode of operation (13010); setting an UL data indication indicating whether the UL data is available for transmission to the first cell group or the second cell group (13050, 13060); transmitting (13070) said UL data indication to a network node (1211, 1212); A method comprising:

2. 2. The method of claim 1, wherein the UL data indication indicates whether the resume procedure is triggered by the uplink data being available only for transmission to the first cell group or whether the uplink data is available for transmission to the second cell group regardless of uplink data available for the first cell group.

3. Setting an UL data indication (13050, 13060) indicating whether the UL data is available for transmission to the first cell group or the second cell group, The UL data indication, a) whether the second cell group bearer has data; b) Whether the split bearer has data Set based on one of the The method of claim 1 or 2, comprising:

4. 4. The method of claim 3, further comprising: setting the UL data indication based on whether an amount of the UL data available for a bearer exceeds a threshold.

5. Setting an UL data indication (13050, 13060) indicating whether the UL data is available for transmission to the first cell group or the second cell group, Checking whether the second cell group bearer has data (13020); If the second cell group bearer has data, setting the UL data indication to indicate that the UL data is available for transmission to the second cell group (SCG) (13060); If the second cell group bearer does not have data, Checking whether the split bearer has data (13030); If the split bearer has no data, setting the UL data indication to indicate that the UL data is available for transmission to the first cell group (MCG) (13050); If the split bearer has data, Checking whether the total amount of data for the split bearer exceeds a split bearer data threshold (13040); if the total amount of data for the split bearer exceeds the split bearer data threshold; setting the UL data indication to indicate that the UL data is available for transmission to the second cell group (SCG) (13060); if the total amount of data for the split bearer does not exceed the split bearer data threshold; setting the UL data indication to indicate that the UL data is available for transmission to the first cell group (MCG) (13050); The method of claim 3 or 4, comprising:

6. Checking whether the second cell group bearer has data (13020) includes: checking whether an amount of data for the second cell group bearer exceeds a second cell group bearer data threshold; determining that the second cell group bearer has data if the amount of data for the second cell group bearer exceeds the second cell group bearer data threshold; The method of claim 5 , comprising:

7. Checking whether the second cell group bearer has data (13020) includes: calculating a sum of the amount of data for all first cell group bearers; calculating a sum of the amount of data for all second cell group bearers; determining that the second cell group bearer has data if the sum of the amount of data for all the second cell group bearers is greater than the sum of the amount of data for all the first cell group bearers or if the sum of the amount of data for all the second cell group bearers exceeds the sum of the amount of data for all the first cell group bearers plus a threshold; The method of claim 5 , comprising:

8. Checking (13040) whether the total amount of data for the split bearer exceeds a split bearer data threshold includes: calculating a sum of the amount of data for all first cell group bearers; calculating a sum of the amount of data for all split bearers; determining that the split bearer has data if the sum of the amount of data for all of the split bearers exceeds the sum of the amount of data for all of the first cell group bearers or if the sum of the amount of data for all of the split bearers exceeds the sum of the amount of data for all of the first cell group bearers plus a threshold; The method of claim 5 , comprising:

9. 9. The method according to claim 1, wherein the UL data indication is included in a resume request message and / or multiplexed with the resume request message for transmission to the network node (1211, 1212).

10. The UL data indication: a) the restart cause contained in the restart request message; b) preambles associated with preamble groups and / or specific time-frequency resources configured by the network node for use by the communications device (1230) for UL data indication; c) data mapped to a second cell group bearer for transmission by the second cell group; d) selection of preamble(s) and / or specific time-frequency resource(s) configured by the network node for the communications device (1230) to use for different UL data indications; e) Resume complete message; f) Information elements in a resume complete message; g) selection of a Physical Random Access Channel (PRACH) resource configured by the network node for use by the communication device (1230) for UL data indication; 10. The method of claim 1, wherein the method is transmitted or indicated as any one of:

11. A communication device (1230) configured to implement the method of any one of claims 1 to 10.

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