Operation of Dual Connectivity in Inactive State

Abstract

To provide operation of dual connectivity in an inactive state.SOLUTION: A WTRU operates in a DC context. While in an RRC_INACTIVE state, the WTRU receives from a first cell a paging message which may be associated with an MCG. The paging message indicates that the WTRU is to respond to the paging message on another cell. The paging message indicates that data for the WTRU is available on an SCG bearer. The WTRU selects a second cell from an SCG list, which may include one or more secondary cells. The WTRU initiates a random access channel procedure with the second cell based on receiving the paging message from the first cell. The WTRU receives data from the second cell via the SCG bearer while in the RRC_INACTIVE state.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] Relates to the operation of dual connectivity in an inactive state.

Background Art

[0002] Cross - reference to related applications This application claims priority based on U.S. Provisional Patent Application No. 62 / 585,944, filed on November 14, 2017, and U.S. Provisional Patent Application No. 62 / 629,382, filed on February 12, 2018, which are hereby incorporated by reference in their entirety.

[0003] Mobile communication using wireless communication is continuously evolving. The fifth generation is sometimes referred to as 5G. The previous (legacy) generations of mobile communication can be, for example, the fourth generation (4G) Long - Term Evolution (LTE).

Summary of the Invention

Problems to be Solved by the Invention

[0004] Provide the operation of dual connectivity in an inactive state.

Means for Solving the Problems

[0005] A wireless transmit - receive unit (WTRU) can operate in a dual - connectivity (DC) mode. While in dual - connectivity, the WTRU can communicate using a master cell group (MCG) and a secondary cell group (SCG). The WTRU can operate in one or more states, such as a radio resource control (RRC) inactive (RRC_INACTIVE) state and / or an RRC connected (RRC_CONNECTED) state.

[0006] While in the RRC_INACTIVE state, the WTRU can receive paging messages from a first cell that can be associated with a master cell group (MCG). The paging message can indicate that the WTRU should respond to the paging message on another cell. The paging message can indicate that data for the WTRU is available on an SCG bearer. The WTRU can select a second cell (e.g., a cell other than the first cell) from a secondary cell group (SCG) list that can include one or more secondary cells. One or more secondary cells can be associated with the same lower layer configuration (e.g., secondary cells of the SCG can share a common physical layer configuration). Based on measurement results, a secondary cell can be selected, e.g., the strongest or best cell on the SCG list can be selected. The WTRU can initiate random access channel (RACH) procedures with the second cell based on receiving a paging message from the first cell. The WTRU can receive data from the second cell via an SCG bearer while in the RRC_INACTIVE state.

[0007] The WTRU can perform mobility related procedures while in the RRC_INACTIVE state. The WTRU can determine (e.g., periodically) quality metrics for one or more secondary cells on the SCG list while in the RRC_INACTIVE state. The WTRU can compare the quality metric for each of the one or more cells with a threshold. When the quality metric for each of the one or more cells exceeds the threshold, the WTRU can transition to the RRC_CONNECTED state. After transitioning to the RRC_CONNECTED state, the WTRU can receive an updated SCG list.

[0008] A system, method, and means for a WTRU to operate in the RRC_INACTIVE state are disclosed. System information (SI) can be provided for a DC configuration applicable to the RRC_INACTIVE state. While the WTRU is in the RRC_INACTIVE state, the WTRU can transition to the RRC_CONNECTED state or perform an area update procedure, for example, based on a secondary node (SN) mobility related trigger for a list of potential primary secondary cells (PSCells). The procedure can support measurement events related to the list of potential PSCs. The WTRU can report SN related measurement information and indications for context update / removal, for example, during a state transition or area update. The WTRU can receive paging and can initiate downlink (DL) data transmission from the SN. The WTRU can send control / data (e.g., associated trigger conditions) to the SN while in the RRC_INACTIVE state.

[0009] A WTRU can request and / or receive SI associated with a set of secondary cells (SCells) in a configured SCell list. The WTRU can request and / or receive from the PCell plausibility information that can be associated with the SCell SI broadcast by the SCell. The WTRU can receive from the PCell, e.g., in a paging message, access parameters applicable to the SCell (e.g., uplink (UL) grant, timing offset, and / or RACH parameters, etc.). The WTRU can configure (e.g., pre-configure) to use a set of dedicated configurations. The WTRU can determine the configurations applicable to the SCell based on signaling within a system information block (SIB). The WTRU can use a configuration (e.g., a default dedicated configuration) for access to the SCell (e.g., access to all SCells). The WTRU can request a non-default dedicated configuration for the SCell (e.g., directly).

[0010] Like reference numerals in the figures indicate like elements.

Brief Description of the Drawings

[0011]

Figure 1A

Figure 1B

Figure 1C

Figure 1D

Figure 2

Figure 3

[0012] A detailed description of the exemplary embodiments will now be made with reference to various figures. This description provides detailed examples of possible implementations, but note that the details are intended to be illustrative and in no way limit the scope of this application.

[0013] Table 1 is a list of acronyms that may be used in this specification.

[0014] **[Table 1-1]**

[0015] **[Table 1-2]**

[0016] **[Table 1-3]**

[0017] FIG. 1A is a diagram illustrating an exemplary communication system 100 that can implement one or more of the disclosed embodiments. The communication system 100 can be a multi-connectivity system that provides content such as voice, data, video, messaging, broadcast, etc. to a plurality of wireless users. The communication system 100 can enable a plurality of wireless users to access such content through sharing of system resources including wireless bandwidth. For example, the communication system 100 can utilize one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero-tail unique word DFT spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, and filter bank multicarrier (FBMC).

[0018] As shown in Figure 1A, the communication system 100 can include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110, and other networks 112, although the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d can be any type of device configured to operate and / or communicate in a wireless environment. By way of example, each of them, which may sometimes be referred to as a “station” and / or “STA”, the WTRUs 102a, 102b, 102c, 102d can be configured to transmit and / or receive wireless signals and can include user equipment (UE), mobile station, fixed or mobile subscriber unit, subscription-based unit, pager, cellular phone, personal digital assistant (PDA), smartphone, laptop, netbook, personal computer, wireless sensor, hotspot or Mi-Fi device, Internet of Things (IoT) device, watch or other wearable, head-mounted display (HMD), vehicle, drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain scenarios), home appliances, and devices operating on commercial and / or industrial wireless networks. Any of the WTRUs 102a, 102b, 102c, 102d may alternatively be referred to as a UE.

[0019] The communication system 100 can also include base station 114a and / or base station 114b. Each of base stations 114a, 114b can be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks such as CN106 / 115, Internet 110, and / or other network 112. By way of example, base stations 114a, 114b can be base transceiver stations (BTSs), Node Bs, eNode Bs, home Node Bs, home eNode Bs, gNBs, NR Node Bs, site controllers, access points (APs), and wireless routers. Although base stations 114a, 114b are each depicted as a single element, it will be understood that base stations 114a, 114b can include any number of interconnected base stations and / or network elements.

[0020] Base station 114a can be part of RAN104 / 113, and RAN104 / 113 can also include other base stations and / or network elements such as base station controllers (BSCs), radio network controllers (RNCs), relay nodes (not shown). Base station 114a and / or base station 114b can be configured to transmit and / or receive radio signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies can be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell can provide coverage for wireless services in a specific geographic area that can be relatively fixed or can change over time. A cell can further be divided into cell sectors. For example, a cell associated with base station 114a can be divided into three sectors. Thus, in one embodiment, base station 114a can include three transceivers, i.e., one for each sector of the cell. In an embodiment, base station 114a can utilize multiple-input multiple-output (MIMO) technology and can utilize multiple transceivers for each sector of the cell. For example, beamforming can be used to transmit and / or receive signals in a desired spatial direction.

[0021] Base stations 114a, 114b can communicate with one or more of WTRUs 102a, 102b, 102c, 102d over air interface 116, which can be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, millimeter wave, infrared (IR), ultraviolet (UV), visible light, etc.). Air interface 116 can be established using any suitable radio access technology (RAT).

[0022] More specifically, as mentioned above, the communication system 100 can be a multi-connection system and can utilize one or more channel access methods such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA. For example, the base station 114a within RAN104 / 113 and the WTRUs 102a, 102b, 102c can implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA) that can establish air interfaces 115 / 116 / 117 using Wideband CDMA (WCDMA). WCDMA can include communication protocols such as High-Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA can include High-Speed Downlink (DL) Packet Access (HSDPA) and / or High-Speed Uplink (UL) Packet Access (HSUPA).

[0023] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c can implement radio technologies such as Evolved UMTS Terrestrial Radio Access (E-UTRA) that can establish the air interface 116 using Long-Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0024] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c can implement radio technologies such as NR Radio Access that can establish the air interface 116 using New Radio (NR).

[0025] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c can implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c can implement LTE radio access and NR radio access together, for example, using the dual connectivity (DC) principle. Accordingly, the air interface utilized by the WTRUs 102a, 102b, 102c can be characterized by transmissions from multiple types of radio access technologies and / or multiple types of base stations (e.g., eNBs and gNBs).

[0026] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c can implement wireless technologies such as IEEE802.11 (i.e., Wireless Fidelity (WiFi)), IEEE802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rate for GSM Evolution (EDGE), and GSM EDGE (GERAN).

[0027] The base station 114b in Fig. 1A can be, for example, a wireless router, a home node B, a home eNode B, or an access point, and can utilize any suitable RAT to facilitate wireless connectivity in a localized area such as an office, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., used by a drone), and a roadway. In one embodiment, the base station 114b and the WTRUs 102c, 102d can implement a wireless technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d can implement a wireless technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d can utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a pico cell or a femto cell. As shown in Fig. 1A, the base station 114b can have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106 / 115.

[0028] RAN 104 / 113 can communicate with CN 106 / 115, which can be any type of network configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRUs 102a, 102b, 102c, 102d. The data can have various Quality of Service (QoS) requirements such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, and mobility requirements. CN 106 / 115 can provide call control, billing services, mobile location-based services, prepaid outgoing calls, Internet connectivity, video distribution, etc., and / or perform high-level security functions such as user authentication. Although not shown in Figure 1A, it will be understood that RAN 104 / 113 and / or CN 106 / 115 can communicate directly or indirectly with other RANs that utilize the same or a different Radio Access Technology (RAT) as RAN 104 / 113. For example, in addition to being connected to RAN 104 / 113 which may be utilizing New Radio (NR) radio technology, CN 106 / 115 can also communicate with another RAN (not shown) that utilizes GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0029] CN106 / 115 can also serve as a gateway for the WTRU102a, 102b, 102c, 102d to access the PSTN108, the Internet 110, and / or other networks 112. The PSTN 108 can include a circuit-switched telephone network that provides basic telephone service (POTS). The Internet 110 can include a worldwide system of interconnected computer networks and devices that use common communication protocols such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) within the TCP / IP Internet protocol suite. The network 112 can include wired and / or wireless communication networks that are owned and / or operated by other service providers. For example, the network 112 can include another CN that is connected to one or more RANs that can utilize the same RAT or a different RAT as the RAN 104 / 113.

[0030] Some or all of the WTRU102a, 102b, 102c, 102d within the communication system 100 can include multimode functionality (e.g., the WTRU102a, 102b, 102c, 102d can include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU102c shown in Figure 1A can be configured to communicate with a base station 114a that can utilize cellular-based wireless technology and with a base station 114b that can utilize IEEE802 wireless technology.

[0031] Figure 1B is a system diagram illustrating an exemplary WTRU102. As shown in Figure 1B, the WTRU102 can include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, a non-removable memory 130, a removable memory 132, a power source 134, a Global Positioning System (GPS) chipset 136, and / or other peripheral devices 138. It will be understood that the WTRU102 can include any sub-combination of the above elements while maintaining consistency with the embodiments.

[0032] The processor 118 can be, for example, a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors cooperating with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), and a state machine, etc. The processor 118 can perform signal encoding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU102 to operate in a wireless environment. The processor 118 can be coupled to the transceiver 120, and the transceiver 120 can be coupled to the transmit / receive element 122. Although Figure 1B depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 can be integrated together in an electronic package or chip.

[0033] The transmitting / receiving element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) over the air interface 116. For example, in one embodiment, the transmitting / receiving element 122 can be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmitting / receiving element 122 can be a radiator / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmitting / receiving element 122 can be configured to transmit and / or receive both RF signals and optical signals. It will be understood that the transmitting / receiving element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0034] In FIG. 1B, the transmitting / receiving element 122 is depicted as a single element, but the WTRU 102 can include any number of transmitting / receiving elements 122. More specifically, the WTRU 102 can utilize MIMO technology. Thus, in one embodiment, the WTRU 102 can include two or more transmitting / receiving elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0035] The transceiver 120 can be configured to modulate signals that are to be transmitted by the transmitting / receiving element 122 and demodulate signals received by the transmitting / receiving element 122. As mentioned above, the WTRU 102 can have a multi-mode function. Thus, the transceiver 120 can include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11, for example.

[0036] The processor 118 of the WTRU 102 can be coupled to the speaker / microphone 124, keypad 126, and / or display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit) and can receive user input data therefrom. The processor 118 can also output user data to the speaker / microphone 124, keypad 126, and / or display / touchpad 128. In addition, the processor 118 can obtain information from and store data in any type of suitable memory, such as the non-removable memory 130 and / or the removable memory 132. The non-removable memory 130 can include random access memory (RAM), read only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 can include a subscriber identity module (SIM) card, a memory stick, and a secure digital (SD) memory card, among others. In other embodiments, the processor 118 can obtain information from and store data in memory that is not physically located on the WTRU 102, such as on a server or home computer (not shown).

[0037] The processor 118 can receive power from the power supply 134 and can be configured to distribute power to and / or control the power to other components within the WTRU 102. The power supply 134 can be any suitable device for powering the WTRU 102. For example, the power supply 134 can include one or more dry cells (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), a solar cell, and a fuel cell, among others.

[0038] Processor 118 can also be coupled to a GPS chipset 136, which can be configured to provide location information (e.g., longitude and latitude) regarding the current location of WTRU 102. In addition to, or instead of, information from the GPS chipset 136, WTRU 102 can receive location information on air interface 116 from a base station (e.g., base stations 114a, 114b), and / or can determine its location based on the timing of signals received from two or more nearby base stations. It will be understood that WTRU 102 can obtain location information using any suitable location determination method while maintaining consistency with the embodiments.

[0039] Processor 118 can further be coupled to other peripheral devices 138, which can include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, peripheral devices 138 can include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photos and / or video), a Universal Serial Bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth® module, a Frequency Modulation (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a Virtual Reality and / or Augmented Reality (VR / AR) device, and an activity tracker, among others. Peripheral devices 138 can include one or more sensors, which can be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0040] The WTRU 102 can include a full-duplex radio in which some or all of the transmission and reception of signals associated with a particular subframe for both the UL (e.g., for transmission) and the downlink (e.g., for reception) can be parallel and / or simultaneous. The full-duplex radio can include an interference management unit 139 to reduce and / or substantially eliminate self-interference, either via hardware (e.g., a choke) or via signal processing through a processor (e.g., a separate processor (not shown) or processor 118). In embodiments, the WTRU 102 can include a half-duplex radio for some or all of the transmission and reception of signals associated with a particular subframe for either the UL (e.g., for transmission) or the downlink (e.g., for reception).

[0041] Figure 1C is a system diagram illustrating a RAN 104 and a CN 106, in accordance with an embodiment. As mentioned above, the RAN 104 can communicate with the WTRU 102a, 102b, 102c over an air interface 116 using E-UTRA radio technology. The RAN 104 can also communicate with the CN 106.

[0042] The RAN 104 can include eNodeBs 160a, 160b, 160c, although it will be understood that the RAN 104 can include any number of eNodeBs while maintaining consistency with the embodiments. The eNodeBs 160a, 160b, 160c can each include one or more transceivers for communicating with the WTRU 102a, 102b, 102c over the air interface 116. In one embodiment, the eNodeBs 160a, 160b, 160c can implement MIMO technology. Thus, the eNodeB 160a, for example, can transmit a wireless signal to and / or receive a wireless signal from the WTRU 102a using multiple antennas.

[0043] Each of the eNodeBs 160a, 160b, 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, and user scheduling in the UL and / or DL. As shown in Figure 1C, the eNodeBs 160a, 160b, 160c can communicate with each other over the X2 interface.

[0044] CN106 shown in Figure 1C can include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) Gateway (or PGW) 166. Although each of the above elements is depicted as part of CN106, it will be understood that any of these elements can be owned and / or operated by an entity different from the CN operator.

[0045] The MME 162 can be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via the S1 interface and can act as a control node. For example, the MME 162 can be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, and selecting a specific serving gateway during the initial attach of the WTRUs 102a, 102b, 102c. The MME 162 can provide control plane functions for handover between the RAN 104 and other RANs (not shown) that utilize other radio technologies such as GSM and / or WCDMA.

[0046] SGW 164 can be connected to each of the eNodeBs 160a, 160b, 160c within RAN 104 via the S1 interface. The SGW 164 can generally route and transfer user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 can perform other functions such as anchoring the user plane during handover between eNodeBs, triggering paging when DL data is available to the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0047] The SGW 164 can be connected to the PGW 166, which can provide access to a packet switched network, such as the Internet 110, to the WTRUs 102a, 102b, 102c and facilitate communication between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0048] The CN 106 can facilitate communication with other networks. For example, the CN 106 can provide access to a circuit switched network, such as the PSTN 108, to the WTRUs 102a, 102b, 102c and facilitate communication between the WTRUs 102a, 102b, 102c and conventional fixed line telephone communication devices. For example, the CN 106 can include, or communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 can provide access to other networks 112 to the WTRUs 102a, 102b, 102c, where the other networks 112 can include other wired and / or wireless networks owned and / or operated by other service providers.

[0049] In FIGS. 1A - 1D, the WTRU is described as a wireless terminal, but in certain representative embodiments, it is contemplated that such a terminal may (e.g., temporarily or permanently) use a wired communication interface to a communication network.

[0050] In a representative embodiment, another network 112 can be a WLAN.

[0051] A WLAN in infrastructure basic service set (BSS) mode can have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP can have an access or interface to a distribution system (DS) or another type of wired / wireless network that carries traffic within and / or outside the BSS. Traffic destined for an STA originating from outside the BSS can arrive through the AP and be delivered to the STA. Traffic transmitted from an STA to a destination outside the BSS can be sent to the AP for delivery to their respective destinations. Traffic between STAs within the BSS can be sent through the AP. For example, the source STA can send the traffic to the AP, and the AP can deliver the traffic to the destination STA. Traffic between STAs within the BSS can be considered peer - to - peer traffic and / or may be referred to as peer - to - peer traffic. Peer - to - peer traffic can be sent (e.g., directly) between the source STA and the destination STA using direct link setup (DLS). In certain representative embodiments, the DLS can use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using independent BSS (IBSS) mode may not have an AP, and STAs within the IBSS or using the IBSS (e.g., all of the STAs) can communicate directly with each other. Communication in IBSS mode is sometimes referred to herein as "ad - hoc" mode communication.

[0052] When using the operation of the 802.11ac infrastructure mode or a similar mode, the AP can transmit beacons on a fixed channel such as the primary channel. The primary channel can be of a fixed width (e.g., 20 MHz bandwidth) or a width dynamically set via signaling. The primary channel can be the operating channel of the BSS and can be used by the STA to establish a connection with the AP. In one representative embodiment, for example, in an 802.11 system, Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) can be implemented. In the case of CSMA / CA, STAs including the AP (e.g., any STA) can sense the primary channel. If the primary channel is sensed / detected by a particular STA and / or determined to be busy, the particular STA can back off. Within a given BSS, at any given time, one STA (e.g., only one STA) can transmit.

[0053] A High Throughput (HT) STA can use a 40 MHz wide channel for communication, for example, by combining the primary 20 MHz channel with adjacent or non - adjacent 20 MHz channels to form a 40 MHz wide channel.

[0054] Very High Throughput (VHT) STAs can support 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. 40 MHz and / or 80 MHz channels can be formed by combining consecutive 20 MHz channels. A 160 MHz channel can be formed by combining eight consecutive 20 MHz channels or by combining two non - consecutive 80 MHz channels, which may be referred to as an 80 + 80 configuration. In the case of the 80 + 80 configuration, after channel encoding, the data can pass through a segment parser that can split the data into two streams. For each stream separately, an Inverse Fast Fourier Transform (IFFT) process and time - domain processing can be performed. The streams can be mapped onto two 80 MHz channels and the data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80 + 80 configuration can be reversed and the combined data can be transmitted to the Medium Access Control (MAC).

[0055] Operation in the sub-1 GHz mode is supported by 802.11af and 802.11ah. The channel operating bandwidth and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV white space (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to an exemplary embodiment, 802.11ah can support meter type control / machine type communication, such as MTC devices in a macro coverage area. The MTC devices can have limited capabilities including certain capabilities, for example, support for a certain bandwidth and / or limited bandwidths (e.g., only those supported by them). The MTC devices can include a battery having a battery life above a threshold (e.g., to maintain a very long battery life).

[0056] WLAN systems that can support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include channels that can be designated as primary channels. The primary channel can have a bandwidth equal to the maximum common operating bandwidth supported by all STAs within a BSS. The bandwidth of the primary channel can be set and / or restricted by the STA that supports the minimum bandwidth operation mode among all STAs operating within the BSS. In the example of 802.11ah, for an STA (e.g., an MTC type device) that supports (e.g., only supports) the 1MHz mode, even if the AP and other STAs within the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operation modes, the primary channel can be 1MHz wide. Carrier sensing and / or network allocation vector (NAV) setting can depend on the status of the primary channel. For example, if the primary channel is busy because an STA (that only supports the 1MHz operation mode) is transmitting to the AP, the entire available frequency band can be considered busy, even though most of the frequency band remains idle and available.

[0057] In the United States, the available frequency band that can be used by 802.11ah is from 902 MHz to 928 MHz. In Korea, the available frequency band is from 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah is from 6 MHz to 26 MHz, depending on national regulations.

[0058] Figure 1D is a system diagram showing RAN 113 and CN 115 according to an embodiment. As mentioned above, RAN 113 can communicate with WTRUs 102a, 102b, 102c over air interface 116 using NR radio technology. RAN 113 can also communicate with CN 115.

[0059] RAN 113 can include gNBs 180a, 180b, 180c, although it will be understood that RAN 113 can include any number of gNBs while maintaining consistency with the embodiment. Each of gNBs 180a, 180b, 180c can include one or more transceivers for communicating with WTRUs 102a, 102b, 102c over air interface 116. In one embodiment, gNBs 180a, 180b, 180c can implement MIMO technology. For example, WTRUs 102a, 108b can use beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, 180c. Thus, gNB 180a, for example, can use multiple antennas to transmit wireless signals to and / or receive wireless signals from WTRU 102a. In an embodiment, gNBs 180a, 180b, 180c can implement carrier aggregation technology. For example, gNB 180a can transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers can be on unlicensed spectrum, while the remaining component carriers can be on licensed spectrum. In an embodiment, gNBs 180a, 180b, 180c can implement multi-site coordinated (CoMP) technology. For example, WTRU 102a can receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0060] WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c using transmissions associated with scalable numerology. For example, the OFDM symbol interval, and / or the OFDM sub-carrier interval can be varied for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c using sub-frames or transmission time intervals (TTIs) of various or scalable lengths (e.g., including various numbers of OFDM symbols and / or lasting for various lengths of absolute time).

[0061] gNBs 180a, 180b, and 180c can be configured to communicate with WTRUs 102a, 102b, and 102c in a stand-alone configuration and / or a non-stand-alone configuration. In a stand-alone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c without accessing other RANs (such as eNodeBs 160a, 160b, and 160c). In a stand-alone configuration, WTRUs 102a, 102b, and 102c can utilize one or more of gNBs 180a, 180b, and 180c as mobility anchor points. In a stand-alone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using signals within an unlicensed band. In a non-stand-alone configuration, WTRUs 102a, 102b, and 102c can communicate with and connect to gNBs 180a, 180b, and 180c while also communicating with / connecting to another RAN such as eNodeBs 160a, 160b, and 160c. For example, WTRUs 102a, 102b, and 102c can implement the DC principle to communicate substantially simultaneously with one or more gNBs 180a, 180b, and 180c and one or more eNodeBs 160a, 160b, and 160c. In a non-stand-alone configuration, eNodeBs 160a, 160b, and 160c can act as mobility anchors for WTRUs 102a, 102b, and 102c, and gNBs 180a, 180b, and 180c can provide additional coverage and / or throughput for serving WTRUs 102a, 102b, and 102c.

[0062] Each of gNBs 180a, 180b, and 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to user plane functions (UPFs) 184a, 184b, and routing of control plane information to access and mobility management functions (AMFs) 182a, 182b. As shown in Figure 1D, gNBs 180a, 180b, and 180c can communicate with each other over the Xn interface.

[0063] CN 115 shown in Figure 1D can include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and possibly data networks (DNs) 185a, 185b. Although each of the above elements is depicted as part of CN 115, it will be understood that any of these elements can be owned and / or operated by entities different from the CN operator.

[0064] AMF 182a and 182b can be connected to one or more of gNBs 180a, 180b, and 180c within RAN 113 via the N2 interface and can serve as control nodes. For example, AMF 182a and 182b can authenticate users of WTRUs 102a, 102b, and 102c, support network slicing (e.g., handling different PDU sessions with different requirements), select specific SMFs 183a and 183b, manage the registration area, terminate NAS signaling, and be responsible for mobility management, etc. Network slicing can be used by AMF 182a and 182b to customize the CN support for WTRUs 102a, 102b, and 102c based on the type of services utilized by WTRUs 102a, 102b, and 102c. For example, different network slices can be established for different use cases such as services that rely on ultra-reliable low-latency (URLLC) access, services that rely on high-speed large-capacity mobile broadband (eMBB) access, and / or services for machine type communication (MTC) access. AMF 162 can provide control plane functions for switching between RAN 113 and other RANs (not shown) that utilize other radio technologies such as non-3GPP access technologies like LTE, LTE-A, LTE-A Pro, and / or WiFi.

[0065] SMF183a and 183b can be connected to AMF182a and 182b within CN115 via the N11 interface. SMF183a and 183b can also be connected to UPF184a and 184b within CN115 via the N4 interface. SMF183a and 183b can select and control UPF184a and 184b and configure the routing of traffic through UPF184a and 184b. SMF183a and 183b can perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, implementing policies and controlling QoS, and providing downlink data notifications. The PDU session type can be IP-based, non-IP-based, and Ethernet-based, etc.

[0066] UPF184a and 184b can be connected to one or more of gNB180a, 180b, and 180c within RAN113 via the N3 interface, and they can provide access to a packet-switched network such as the Internet 110 to WTRU102a, 102b, and 102c to facilitate communication between WTRU102a, 102b, and 102c and IP-compatible devices. UPF184a and 184b can perform other functions such as routing and forwarding packets, implementing user plane policies, supporting multi-homing PDU sessions, processing user plane QoS, buffering downlink packets, and providing mobility anchoring.

[0067] CN115 can facilitate communication with other networks. For example, CN115 can include, or communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between CN115 and the PSTN 108. In addition, CN115 can provide access to other networks 112 to the WTRUs 102a, 102b, 102c, and the other networks 112 can include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c can be connected to the local data networks (DNs) 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0068] With reference to FIGS. 1A - 1D and the corresponding descriptions thereof, one or more of the functions described herein with respect to one or more of the WTRUs 102a - d, base stations 114a - b, eNodeBs 160a - c, MME 162, SGW 164, PGW 166, gNBs 180a - c, AMFs 182a - b, UPFs 184a - b, SMFs 183a - b, DNs 185a - b, and / or any other devices described herein can be performed by one or more emulation devices (not shown). An emulation device can be one or more devices configured to emulate one or more or all of the functions described herein. For example, an emulation device can be used to test other devices and / or to simulate network and / or WTRU functionality.

[0069] An emulation device can be designed to perform one or more tests of other devices in a laboratory environment and / or in an operator network environment. For example, one or more emulation devices can execute one or more or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices within the communication network. One or more emulation devices can execute one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. An emulation device can be directly coupled to another device for testing purposes and / or can use over-the-air wireless communication to perform the test.

[0070] One or more emulation devices can execute one or more functions including all functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, an emulation device can be utilized in a test scenario in a test laboratory and / or in a non-deployed (e.g., test) wired and / or wireless communication network to perform tests of one or more components. One or more emulation devices can be test equipment. Direct RF coupling and / or wireless communication via an RF circuit (which can include one or more antennas for example) can be used by an emulation device to transmit and / or receive data.

[0071] The examples provided herein do not limit the applicability of the subject matter to other wireless technologies that use the same or different principles that can be applicable, for example.

[0072] The network may refer to one or more gNBs that can be associated with one or more transmit / receive points (TRPs) or other nodes within a radio access network (RAN).

[0073] In NR and / or other radio access technology types, an RRC state (e.g., RRC_INACTIVE) can exist. The RRC_INACTIVE state can be characterized by, for example, one or more of the following: cell reselection mobility, a CN-NR RAN connection established for the WTRU (e.g., both C / U planes), the ability to store the access stratum (AS) context of the WTRU in at least one gNB and within the WTRU, the ability to initiate paging by the NR RAN, the ability to manage a RAN-based notification area by the NR RAN, and / or the ability of the NR RAN to know the RAN-based notification area to which the WTRU belongs.

[0074] The signaling for the transition between the RRC_INACTIVE state and the RRC_CONNECTED state can include, for example, the WTRU transmitting and / or receiving an RRC message indicating that the RRC connection should be resumed. During a suspension procedure, the interruption-resumption signaling for (e.g., in LTE) machine-type cellular Internet of Things (CIoT) that can maintain the context can utilize similar resumption signaling.

[0075] (e.g., in LTE and / or NR) The WTRU can support dual connectivity (DC) operation.

[0076] A DC WTRU in the RRC_CONNECTED state can be configured (e.g., in LTE) to utilize radio resources provided by multiple (e.g., two) different schedulers that can be clearly located within multiple (e.g., two) eNB / gNBs connected (e.g., via a backhaul over the X2 interface). The eNBs included in the DC for the WTRU can assume multiple (e.g., two) different roles. The eNB can serve, for example, as a master eNB (MeNB) / master gNB (MgNB) or as a secondary eNB (SeNB) / secondary gNB (SgNB). The WTRU (e.g., in the DC) can be connected to the MeNB and / or SeNB. A WTRU configured to use DC may, for example, release or not release the secondary cell group (SCG) configuration (e.g., in relation to a suspend / resume procedure) when restarting an RRC connection (e.g., when the WTRU transitions to the RRC_CONNECTED state).

[0077] (E.g., in NR) DC between multiple gNBs can be supported. (E.g., in NR) Multi-RAT DC (MR-DC) between a master node (MN) and a secondary node (SN) can be supported. MR-DC can take one or more of the following forms, namely, E-UTRA-NR dual connectivity (EN-DC) where the MN can be LTE, the SN can be NR, and the core network (CN) can be LTE, NG-RAN E-UTRA-NR dual connectivity (NGEN-DC) where the LTE CN is replaced by an NR CN, and NR-E-UTRA dual connectivity (NE-DC) where the MN can be NR, the SN can be LTE, and the CN can be NR. A WTRU can (e.g., often) transition between an RRC_INACTIVE state and an RRC_CONNECTED state (e.g., in NR). After each state transition (e.g., each state transition), if a reconfiguration of the DC configuration is to be performed, a WTRU configured to use DC may incur a relatively large amount of signaling overhead to disconnect and / or re - establish the CN - RAN connection to the SN, in addition to network (NW) signaling. The techniques described herein can enable a WTRU to transition from the RRC_INACTIVE state to the RRC_CONNECTED state and also transition from the RRC_CONNECTED state using reduced signaling overhead.

[0078] The WTRU and / or the NW can evaluate the validity of a DC configuration (e.g., the current DC configuration) in view of the mobility of the WTRU. The WTRU can perform maintaining a proper configuration.

[0079] For example, for reconfiguration, the maintenance of the CN - RAN interface with the SN can be implemented by transferring data to the WTRU or the NW on the SCG bearer using minimal signaling / latency. For example, when the CN - RAN interface is switched (e.g., due to WTRU mobility), the NW can be (e.g., additionally) notified.

[0080] The WTRU can be configured to perform DC while in an inactive state (e.g., the RRC_INACTIVE state). The WTRU can, for example, perform mobility while in the inactive state.

[0081] While in the RRC_INACTIVE state, the WTRU can maintain the exact / applicable DC configuration of one or more cells. The WTRU can perform measurements (e.g., RRM) of, for example, connected SN cells and / or neighbor cells (e.g., when a change of cell or SN node may be required). While in the RRC_INACTIVE state, the WTRU can, for example, obtain (e.g., be made available to obtain) the configuration of the PSCell.

[0082] While in the RRC_INACTIVE state, the WTRU can receive SI messages. While in the RRC_INACTIVE state, the WTRU can use the SI messages to perform DC.

[0083] As described herein, a WTRU can receive one or more SI messages that can be used to perform DC while in the RRC_INACTIVE state. The amount and / or size of the SI messages received by the WTRU can be reduced. SI for the WTRU can be used for DC operation / maintenance while the WTRU is in the RRC_INACTIVE state (e.g., DC_Inactive_SI). SI can be transmitted with one or more system information blocks (SIBs) / SI messages that can be dedicated for that purpose. A cell that can be configured as a primary secondary cell (PSCell) (e.g., for a given WTRU) can broadcast (e.g., periodically broadcast) an SIB or SI message. In an example, when there are no WTRUs in DC that are currently configured to use a given PSCell or surrounding PSCs, the network can stop (e.g., cease) broadcasting on SIB / SI. The SI message can be transmitted (e.g., alternatively transmitted) by a primary cell (PCell) as part of the system information of the PCell itself. The content of the SI message can include, for example, one or more of the following: parameters associated with SN selection / reselection (e.g., thresholds), parameters used to perform measurements of the PSCell (e.g., cell bandwidth, RS configuration, measurement configuration, event configuration specific to the INACTIVE state, etc.), parameters associated with the transmission of data and / or (e.g., direct) RRC signaling to the SN while in the RRC_INACTIVE state (e.g., WTRU state, thresholds, etc.), L1 / L2 configuration for the PSCell, and / or one or more of the potential PSCs that can be associated with the PCell or a PCell that can be configured upon transition to the RRC_INACTIVE state or the PSCell.

[0084] The WTRU can receive a certain SI that can be used by the WTRU to perform measurements and / or cell reselection decisions. For example, the WTRU can receive DC_Inactive_SI that can be used by the WTRU to perform measurements and / or PSCell reselection decisions. DC_Inactive_SI can include information that enables the WTRU to access the PSCell while the WTRU is in the RRC_INACTIVE state. For example, DC_Inactive_SI can include random access channel (RACH) parameters.

[0085] The WTRU can receive SI (e.g., DC_Inactive_SI) from the MN associated with the SN.

[0086] The WTRU can request SI (e.g., DC_Inactive_SI) from the MN, receive SI from the MN, and / or be able to read it. The WTRU can request SI, for example, by using an on-demand request procedure. When the WTRU requests SI using an on-demand request procedure, broadcast of such information (e.g., constantly) by the cell can be avoided. The WTRU can obtain plausibility information and / or scheduling information for receiving SI from the minimum SI of the MN (similarly to any other SI, for example). The WTRU can request SI specific to the PSCell and / or PCell, for example, by including the PSCell / PCell cell ID within the on-demand request. The WTRU can include the PSCell ID within MSG3 of the SI request to receive system information for the SN PSCell, for example. The WTRU can select the PRACH time / frequency resources and / or preamble associated with the PSCell (e.g., based on configuration). The WTRU can transmit the PSCell ID in a multi-step (e.g., two-step) RACH. For example, the WTRU can request PSCell-specific SI via the multi-step RACH. The WTRU can obtain separate DC_Inactive_SI for one or more (e.g., all) potential PSCs for a given PCell using, for example, a single request. The WTRU can obtain SI for a set of SCell associated with the SN (e.g., according to a pre-configured SCell list). For example, when the WTRU transitions from the RRC_CONNECTED state to the RRC_INACTIVE state, the WTRU can be configured to use the SCell list. The WTRU can include information indicating the SCell list for which the WTRU requests configuration information (e.g., within the SI request).

[0087] The WTRU can receive and / or read DC_Inactive_SI (e.g., directly) from the SI broadcast of the SN. The WTRU can be configured to determine, assume, or know that it can broadcast information, e.g., in an SIB or SI message, that can be provided on a cell that can serve as a PSCell (e.g., among non-standalone (NSA) NR cells). The WTRU can obtain plausibility information (e.g., a value tag) and / or scheduling information associated with cell reselection SI from the master PCell. The WTRU can determine whether and when to obtain new SI (e.g., associated with SN reselection parameters) based on the acquisition of plausibility and / or scheduling information at the minimum SI that can be broadcast (e.g., by the PCell). The WTRU can receive plausibility information and / or scheduling information from the SN (e.g., directly). The WTRU can read the minimum SI that can be broadcast periodically (e.g., upon each wake-up of the WTRU's Inactive state DRX cycle) by the PSCell to determine whether to obtain new DC_Inactive_SI.

[0088] The WTRU can receive valid information about the SI of the SCell from the PCell through the SI request procedure, and can receive the actual SI associated with the SCell from the broadcast of the SCell (e.g., directly). The PCell and the SCell may not broadcast the scheduling and / or valid information of the SI of the SCell, and the SCell may not broadcast the SI (e.g., the actual SI). The WTRU can trigger the SCell to start broadcasting the relevant SI of the SCell (e.g., by sending an SI request to the MN). The WTRU can receive the scheduling and valid information (e.g., simultaneously) from the PCell (e.g., directly).

[0089] The WTRU can obtain the SI about the PSCell (e.g., the SN cell) from the previously obtained SI. The WTRU can store the previously obtained SI about the cell (e.g., the SN cell and / or the PSCell). While the WTRU was camped / connected to the cell (e.g., connected to the cell as the PCell), the WTRU can have the previously obtained SI. The WTRU can have the previously obtained SI with or without configuring dual connectivity. The WTRU can use the previously obtained SI when it is for the cell (e.g., when the WTRU uses the cell as the SN and / or the PSCell).

[0090] The WTRU can receive an indication of the SN configuration in a paging message.

[0091] The WTRU can receive a notification that can indicate to the WTRU to use a new SN configuration (e.g., applicable to one or more SN cells (PSCell / SCell)). For example, the WTRU can receive the notification in a paging message. The WTRU can receive the paging message from the MN. The WTRU can receive an indication (e.g., in a paging message) that an SI change is applicable to DC_Inactive_SI.

[0092] The WTRU can be configured to use a list of potential PSCell / SN SCells.

[0093] The WTRU can be configured (e.g., implicitly or explicitly) to use a list of SCG cells in which the WTRU can perform mobility (e.g., while in the RRC_INACTIVE state), can perform direct data / control transmissions (e.g., without transitioning to the RRC_CONNECTED state) while in the RRC_INACTIVE state, and / or can start a transition to the RRC_CONNECTED state (e.g., to update the WTRU's DC context in the network) and can perform one or more measurements for that purpose. Such a list can be configured in the WTRU while the WTRU is in the RRC_CONNECTED state or can be configured in the WTRU during a transition from the RRC_CONNECTED state to the RRC_INACTIVE state.

[0094] The WTRU can be configured to use one or more triggers for the WTRU to transition to and / or from the RRC_CONNECTED state and / or one or more triggers for the WTRU to perform an area update. For example, the triggers can be based on the mobility of the WTRU and / or the state of the WTRU with respect to the SN.

[0095] The WTRU can transition to the RRC_CONNECTED state or perform an area update based on one or more triggers (e.g., mobility events, measurements that can be related to a PSCell or SCell, or traffic characteristics that can be related to a PSCell or SCell). The transition to the RRC_CONNECTED state can be performed (e.g., by the WTRU) to notify the network of one or more of the following, namely, the need to update the PSCell in a DC configuration, the need to clear / update the context in one or more network nodes, and / or the movement of the WTRU outside a particular area of SN coverage. As described herein, the WTRU can transition to the RRC_CONNECTED state based on triggers (e.g., quality measurements that can be related to a PSCell or SCell, or traffic characteristics that can be related to a PSCell or SCell). The trigger can include comparing the quality measurement or traffic characteristic to a threshold.

[0096] The transition to the RRC_CONNECTED state can follow a procedure that can be, for example, a resume procedure (e.g., a resume procedure for NR). The area update procedure can follow a procedure that can be, for example, similar to the RAN area update procedure for NR.

[0097] The WTRU can be configured to use a trigger for the WTRU to transition to the RRC_CONNECTED state. The configuration of the trigger for transitioning to the RRC_CONNECTED state can be provided, for example, via RRC signaling (e.g., dedicated RRC signaling while in the RRC_CONNECTED state). The RRC signaling can be received from the MN or (e.g., directly) from the SN (e.g., via Signaling Radio Bearer 3 (SRB3)). The WTRU can receive the trigger configuration in a message (e.g., also in a message), which can cause the WTRU to suspend and enter the RRC_INACTIVE state. The WTRU can receive the configuration in an encapsulated RRC message that can be generated by the SN (e.g., when the configuration needs to be sent by the SN) (e.g., in the case of MR-DC).

[0098] The WTRU can be configured to use a trigger for the WTRU to transition to the RRC_CONNECTED state based on the cell quality of a list of cells.

[0099] The WTRU can be configured to use a list of cells (e.g., cell IDs) that can correspond to the range of potential PSCell candidates while the WTRU is in the RRC_INACTIVE state. The set of PSCell candidates can correspond to cells that are associated with, for example, a single SN, a single security key for the SN. The set of PSCell candidates can correspond to a list of cells that can maintain the CN-RAN connection, for example, during mobility.

[0100] The WTRU can be configured to use measurement events that can be associated with a list of cells. The measurement events can (e.g., when triggered) initiate a transition to the RRC_CONNECTED state and can be defined, for example, based on the fact that one or more cells are no longer suitable for communication. One or more of the following can be applied, i.e., the measured quality of all or a subset of SCG cells can fall below a threshold for a certain period of time, the measured quality of the PSCell and a given number of other cells in the list can fall below a threshold for a certain period of time, and / or the measured quality of one or more cells that are not part of a list of cells (e.g., a list of PSCells) can become better than a threshold for a subset of cells in the list of cells for a certain period of time.

[0101] The WTRU can be configured to use a trigger for the WTRU to transition to the RRC_CONNECTED state based on cell quality within an area.

[0102] (E.g., as described herein) Measurement events can be defined, for example, by the absence of at least one cell that broadcasts a signature, a set of associated signatures, and / or an identifier (e.g., an area ID) that can be unique to an area or a list of cells. The WTRU can determine that a signature or area ID is similar to (e.g., the same as) the signature / area ID associated with the PSCell (e.g., when the WTRU was in the RRC_INACTIVE state). The transition to the RRC_CONNECTED state, or an area update procedure, can be initiated, for example, based on the inability to maintain a certain measured quality for at least one cell. For example, the transition to the RRC_CONNECTED state, or an area update procedure, can be initiated based on the measured quality metric falling below a threshold.

[0103] The WTRU can be configured to use a trigger for the WTRU to transition to the RRC_CONNECTED state based on inactivity.

[0104] The WTRU can be configured to use, for example, an inactivity timer or an SCG release timer (e.g., an RRC-configured SCG release timer). The inactivity timer can be associated with data transmission to the SN (e.g., by the WTRU). The WTRU can transition to the RRC_CONNECTED state, for example, when the inactivity timer expires. The inactivity timer can start, for example, when the WTRU transitions to the RRC_INACTIVE state. The inactivity timer can be reset, for example, when one or more of the following occur: i.e., when the WTRU transmits and / or receives data on a DRB and / or SRB (e.g., an SCG DRB) associated with the SN (e.g., associated with only the SN), when the WTRU transitions to the RRC_CONNECTED state, and / or when the WTRU transitions to the RRC_INACTIVE state (e.g., transitions back to the RRC_INACTIVE state later). Resetting of the inactivity timer for a split DRB (e.g., a DRB that can transmit data to the MN or SN) can depend on the UL path selected for data transmission. Rules for determining the UL path for a split DRB while the WTRU is in the RRC_INACTIVE state can be similar to (e.g., the same as) the rules for determining the UL path while the WTRU is in the RRC_CONNECTED state. Also, or alternatively, rules for UL path determination for a split DRB (and / or, e.g., rules for resetting the inactivity timer) while the WTRU is in the RRC_INACTIVE state can be different from the rules for UL path determination while the WTRU is in the RRC_CONNECTED state, for example, when the WTRU is configured to transmit data to the MN on a certain split bearer while in the RRC_INACTIVE state.

[0105] The WTRU can be configured to use a trigger to indicate that the WTRU should transition to the RRC_CONNECTED state based on MN mobility.

[0106] The WTRU can be configured to use a trigger to indicate that the WTRU should transition to the RRC_CONNECTED state based on, for example, MN mobility. The transition can be applicable, for example, when the WTRU is configured to use dual connectivity while in the RRC_INACTIVE state (e.g., only then). While in the RRC_INACTIVE state, a WTRU configured to use DC can transition to the RRC_CONNECTED state, for example, when the WTRU performs cell reselection on a cell that is not the PCell (e.g., the current PCell when the WTRU transitions to the RRC_INACTIVE state). Also, or alternatively, the WTRU can be configured to use an area (e.g., an area different from the RAN area) that can define a list of PCells (e.g., potential PCells). Reselection of a cell outside the area can trigger a transition to the RRC_CONNECTED state. For example, when the DC configuration is not maintained / active, the trigger based on MN mobility can be disabled for a WTRU in the RRC_INACTIVE state.

[0107] The WTRU can be configured to use a trigger to indicate that the WTRU should transition to the RRC_CONNECTED state based on a configuration change (e.g., a configuration change that no longer permits direct access).

[0108] The WTRU can be configured to use a trigger to indicate that the WTRU should transition to the RRC_CONNECTED state when, for example, the SI associated with one or more potential PSCs or SCGs changes. When the SI associated with one or more potential PSCs or SCGs changes, the WTRU may not be able to access a cell for data transmission without transitioning to the RRC_CONNECTED state (e.g., it may not be able to access). In an example, the WTRU can receive a portion of the SI (e.g., the complete SI) that is applicable to the SCG. The WTRU can re-acquire the complete SI (e.g., the SCG configuration) while the WTRU is in the RRC_CONNECTED state to account for a change in the indication of the SI (e.g., a specific indication). A change in the SI configuration can indicate a change in the security parameters or data transmission parameters that can be obtained while in the RRC_CONNECTED state (e.g., alternatively, can indicate).

[0109] The WTRU can be configured to use one or more of the triggers described herein. For example, the WTRU can be configured to use any of the triggers described herein, or any combination of those triggers. The WTRU can, for example, transition to the RRC_CONNECTED state or trigger an area update procedure to clear / update the context in the NW when it detects that any or all of the (configured and / or potential) PSCs or SCGs are not suitable for access (e.g., based on measurements and / or expiration of a configured SCG release timer).

[0110] The WTRU can behave in one or more of the following ways before, during, and / or after a transition to the RRC_CONNECTED state or an area update.

[0111] The WTRU can transition to the RRC_CONNECTED state or initiate an area update based on a trigger, receipt of a message, and / or arrival of UL data. For example, the WTRU can transition to the RRC_CONNECTED state or initiate an area update based on one or more of the following, namely, receipt of a paging message, arrival of UL data at the WTRU, and / or one or more of one or more triggers. The WTRU can provide information indicating the current mobility state of the SN node (e.g., as a result of the transition).

[0112] The WTRU can be configured to transmit information when the WTRU transitions to the RRC_CONNECTED state. For example, during the transition to the RRC_CONNECTED state, the WTRU can transmit one or more of the following, namely, an indication to the NW to delete or change the SN configuration or to change the WTRU context to a single connectivity context, an indication to the NW as to whether the quality of a previously configured PSCell can exceed a threshold, an indication of one or more cells having a quality exceeding a (e.g., specific) threshold, an indication of the best cell or selected cell from a list of configured potential PSCs (e.g., based on a decision mechanism described herein), and / or one or more of the measurement values of a set of cells (including, for example, the PSCell, potential PSCs, and other detected cells on the same frequency as the PSCell). In an example, the inclusion / reporting of the measurement values can be based on the trigger of an event that can occur during mobility while the WTRU is in the RRC_INACTIVE state (e.g., as described herein).

[0113] The WTRU can send the information described herein in one or more messages. For example, the WTRU can send the information described herein in MSG3 of the RRC procedure and / or in a message after the RRC procedure. The WTRU can execute RRC procedures for a state transition to the RRC_CONNECTED state or an area update. The WTRU can send an indication of SN configuration deletion in MSG3. The WTRU can send a bitmap of cells (e.g., referring to a preconfigured list of cells) that have a quality metric exceeding a configured threshold. The WTRU can send the cell ID or other (e.g., similar) identification information of a potential cell (e.g., the best potential PSCell). The WTRU can send a null ID, for example, when there are no potential PSCs for which the measurement value exceeds the threshold.

[0114] The WTRU can be configured to perform measurement event memorization and / or reporting while the WTRU is in the RRC_INACTIVE state.

[0115] The WTRU can be configured to perform one or more measurements during a transition to the RRC_CONNECTED state or during an area update. The WTRU can perform measurements based on the triggering of one or more SN-related events. For example, the SN-related events can be triggered during WTRU mobility while in the RRC_INACTIVE state. The WTRU can include one or more measurement values in the messaging sent to the NW during a state transition or an area update, for example, for each triggered event.

[0116] The WTRU can be configured to use one or more events (e.g., certain events) that can trigger a state transition or an area update procedure (e.g., an immediate state transition or area update procedure). The WTRU can be configured to use one or more events that can trigger the inclusion / addition of one or more associated measurements, which can be associated with the event, into a report (e.g., a final measurement report). The report can be transmitted, for example, when a state transition trigger occurs. An event can result in the addition of one or more measurements to a measurement report without a state transition. The WTRU can cancel or remove previously added measurements, for example, when another event is triggered (e.g., when the WTRU exits and re-enters an area that can be defined by a potential PSCell).

[0117] The WTRU can transform its RRC context based on SN inactivity.

[0118] The WTRU can be configured to use an inactive timer that can be associated with data transmission to the SN. All (e.g., all) RRC contexts associated with the SN can be updated and / or deleted, for example, upon expiration of the timer. The timer (e.g., the inactive timer) can be reset when the WTRU transmits and / or receives data, for example, on any DRB and / or SRB (e.g., SCG DRB) associated with (e.g., only associated with) the SN. Resetting the timer (e.g., the inactive timer) for a split DRB (e.g., a DRB for which data is transmitted to the MN or SN) can be conditional upon rules that can be the same as the rules used to determine the UL path for data transmission. The rules for resetting the timer (e.g., the inactive timer) can be the same as those for RRC_CONNECTED. The rules for resetting the timer (e.g., the inactive timer) can be different while the WTRU is in the RRC_INACTIVE state. The WTRU can be configured to transmit data to the MN on a split bearer (e.g., a certain split bearer) while in the RRC_INACTIVE state.

[0119] The WTRU can convert the WTRU's DC context to a single connectivity context (e.g., upon expiration of a timer). The WTRU can perform one or more of the following, namely, deleting the SN configuration (e.g., including DC_Inactive_SI), deleting the connectivity context associated with the SN (e.g., any connectivity context), stopping the execution of measurements related to SN mobility, and applying a single connectivity context. The connectivity context can be derived by the network, e.g., based on one or more predefined rules and / or pre-configurations (e.g., when the WTRU transitions to the RRC_INACTIVE state or when the WTRU uses DC).

[0120] The WTRU can transmit and / or receive data / control via the SN while in the RRC_INACTIVE state.

[0121] The WTRU in the RRC_INACTIVE state can transmit and / or receive data / RRC signaling from the PSCell while remaining in the RRC_INACTIVE state. The WTRU can remain in the RRC_INACTIVE state, for example, by performing limited operations with the MN and communicating with the SN. For example, when the data / RRC signaling is associated with an anchor and the DRB / SRB transmitted on the SN leg (e.g., only on the SN leg), the WTRU can remain in the RRC_INACTIVE state (which can be advantageous, for example).

[0122] The WTRU can receive a paging message via a cell (e.g., the MN) to trigger DL data reception from another cell (e.g., the SN).

[0123] The WTRU can receive a paging message from the MN, for example, to initiate DL data reception at the SN. The paging message can be received by the WTRU while the WTRU is in the RRC_INACTIVE state. The WTRU can receive DL data from the SN (e.g., based on receiving a paging message from the MN) while the WTRU remains in the RRC_INACTIVE state. The paging message can include information indicating, for example, one or more of the following: the WTRU ID, the cell ID of the PSCell (e.g., for receiving DL data), the beam information of the PSCell (e.g., beam ID) (e.g., for receiving DL data), an indication that the WTRU can receive DL data from the SN while remaining in RRC_INACTIVE, the C-RNTI (e.g., used by the WTRU for DL data reception), the time offset (e.g., for the required access or until DL data reception on the PSCell after paging transmission), and / or the time duration (e.g., for data transmission or control channel monitoring via the PSCell). The time duration can be measured, for example, as one or more of the following: the absolute period of time, the number of frames / subframes / slots / minislots, the number of PDUs transmitted (e.g., in any given layer). The paging message can include the uplink timing difference for the PSCell / SCell. The WTRU can use the uplink timing difference for the PSCell / SCell for UL transmission (e.g., when transmitting UL data via the SN). The paging message can include an uplink grant within the indicated PSCell / SCell that the WTRU can use for UL transmission to the SN.The paging message can include contention - free random access parameters for the PS Cell / SCell (e.g., SN cell) during the random access procedure for the SN cell (e.g., indicated by the network or selected by the WTRU). Such parameters can be common to the cells (e.g., all cells) within the configured SCG list, or a list of such parameters corresponding to individual cells within the SCG list can be transmitted.

[0124] The WTRU can receive a paging message from a cell and perform one or more actions to activate data and / or control information on another cell. For example, when the WTRU successfully receives a paging message, the WTRU can perform one or more of the following, i.e., for example, to obtain uplink timing alignment and / or beam information for transmission / reception to / from the PSCell, and / or to notify the NW about the PSCell on which DL data should be transmitted, initiate a RACH procedure or RACH-like procedure for one or more PSCells, start monitoring the control channel (e.g., using a C-RNTI that can be provided in the paging message or in the RACH procedure while remaining in the RRC_INACTIVE state), and / or start a resume procedure with the MN (which can include a transition to the RRC_CONNECTED state). One or more of the following can be applied. When the SN cell indicated in the paging message is not the best measured cell in the SCG list, or when the SN has a quality below a certain threshold, the WTRU can start a resume procedure with the MN. When the WTRU cannot measure any cell in the SCG list that exceeds a threshold (e.g., a quality threshold and / or a measurement result threshold), the WTRU can start a resume procedure with the MN. When the initial RACH procedure or RACH-like procedure for the SN cell fails, the WTRU can start a resume procedure with the MN. When the WTRU does not receive a DL message including a C-RNTI on any of the DL SN cells during a specified or configured period of time, the WTRU can start a resume procedure with the MN. When the WTRU receives UL data (e.g., UL data that is larger than a certain amount or size and / or has certain latency or reliability characteristics) while monitoring the DL control channel of the SN cell, the WTRU can start a resume procedure with the MN.

[0125] The WTRU can assume, receive, and / or determine configured, pre-configured, and / or defined time offsets. For example, the time offset can be the time between when the WTRU receives a paging message on the PCell and when the WTRU performs a RACH transmission to the PSCell and / or when the WTRU monitors the PSCell control channel.

[0126] The WTRU can perform the actions described herein simultaneously for one or more potential PSCs. The WTRU can monitor control channels on one or more (e.g., all) PSCs within a list (e.g., SCG list) that can be configured by the network. The WTRU can notify the network as to on which PSC further DL data should be sent. The WTRU can notify the network, for example, after data reception (e.g., only during the transmission of the first positive acknowledgement), as to on which PSC further DL data should be sent.

[0127] The WTRU can receive a paging message indicating that the WTRU should receive DL data from the SN. The WTRU can select a particular cell to use (e.g., select a cell from a list of cells) and can indicate the selected cell to the NW. The selected cell can be indicated to the network by the WTRU by initiating a RACH procedure for the cell selected by the WTRU (e.g., directly). The WTRU can receive a C-RNTI from the RACH procedure and can use the obtained C-RNTI to monitor the PDCCH.

[0128] The WTRU can receive a paging message indicating that the WTRU should receive DL data from the SN. For example, the paging message can indicate the DL cell on which the WTRU should receive data, and / or the C-RNTI and timing offset used by the WTRU within the target cell. The WTRU can perform a RACH (e.g., directly) for the cell selected by the NW, and / or monitor the PDCCH using the C-RNTI (e.g., the C-RNTI provided within the paging message).

[0129] The WTRU can transmit data / control to the SN while in the RRC_INACTIVE state.

[0130] The WTRU can start data transmission, for example, to the last configured PSCell or potential PSCell, upon arrival of UL data at the WTRU. The WTRU can start data transmission to the PSCell when, for example, data arrives for an SCG bearer. The WTRU can start data transmission to the PSCell when, for example, data arrives for a split bearer that can be anchored at the SN (e.g., when the rules configured for transmission to the split bearer require transmission of packets to the SN). The WTRU can determine to start data transmission (e.g., instead of resuming at the SN) based on one or more of the following: when the amount of data transmitted on one or more of an SCG bearer or split bearer is less than a (e.g., configured) threshold, when the data is not pending on any (e.g., non-SCG) bearer, when the data is associated with a certain priority (e.g., based on a data QoS label or associated logical channel), and / or when the control (e.g., RRC message) is associated with a message that can be transmitted (e.g., normally transmitted) on SRB3.

[0131] The WTRU can be configured to send one or more RRC messages (e.g., directly to the SN via SRB3) that can be associated with SN mobility. The WTRU can perform an area update procedure (e.g., directly to the SN) without transitioning to the RRC_CONNECTED state, for example.

[0132] The WTRU can perform security procedures before transmitting data to the SN and / or initiating a resume procedure.

[0133] The WTRU can perform data transmission and / or resume procedures with the SN. The WTRU can derive a key for encryption (e.g., a new key for encryption). The WTRU can use a key for encrypting data / control messages to be sent to the SN (before such transmission). The WTRU can receive a key derivation material for use with the SN. The key derivation material can include National Communications Commission (NCC) parameters for use with the SN (e.g., SN-NCC), and / or a security key counter (e.g., a new SK counter). The WTRU can receive the key derivation material during resume procedures and / or when the WTRU transitions to the RRC_INACTIVE state (e.g., suspended by the MN into the RRC_INACTIVE state). The WTRU can receive the key derivation material directly from the SN. The WTRU can receive the key derivation material in a container. The container can include a transparent container that the WTRU can receive in a suspension message. The suspension message can be provided to the WTRU by the SN. For example, the suspension message can be provided to the MN by the SN (e.g., through inter-node messaging), and the MN can provide the suspension message to the WTRU as a transparent container within an MN release message. The WTRU can assume that the SN key derivation material is a function of the MN key derivation material.

[0134] As described herein, the WTRU can derive a key for encrypting data / control to be sent to the SN based on a function. One or more of the following, namely, a previous key, the cell ID of the PSCell to which the WTRU is sending or has sent data or control, the stored WTRU ID, timing information (e.g., SFN, slot number, etc.), the newly derived MN key, and / or one or more of the information obtained from the MN can be inputs and / or parameters to the key derivation function. As described herein, the WTRU can use a previous key to derive a key for encrypting data / control to be sent to the SN. The WTRU could use a previous key (e.g., a security context previously stored by the WTRU) for data / control sent to a previous SN and / or a previous MN. As described herein, the WTRU can use the newly derived MN key to derive a key for encrypting data / control to be sent to the SN. For example, the WTRU can derive a newly derived SN key as a function of the newly derived MN key. As described herein, the WTRU can use the information obtained from the MN to derive a key for encrypting data / control to be sent to the SN. For example, the WTRU can obtain information after an RRC message exchange with the MN.

[0135] The WTRU can initiate an RRC procedure with the MN in order to enable the derivation of the MN key and / or to obtain key material for the derivation of the SN key. The RRC procedure can be similar to a resume procedure. The RRC procedure can include a resume request message. The resume request message can include an indicator or flag that can indicate a request for resume to the MN. In response to the resume request, the WTRU can receive a suspension-like message from the MN. The message can provide the SN key material to the WTRU. The message can include information that enables the WTRU to derive a new MN key and / or key material applicable to the SN (e.g., NCC, sk counter). The WTRU can derive the SN key as a function of the new MN key and / or the received key material.

[0136] The WTRU can directly resume the connection with the SN. The WTRU can be configured in dual connectivity. While in the RRC_INACTIVE state, the WTRU can directly execute a resume procedure for the SN PSCell.

[0137] The WTRU can initiate a resume procedure with the SN based on one or more triggers. For example, the WTRU can execute a resume procedure with the SN based on one or more of the following triggers.

[0138] The WTRU can execute a resume procedure with the SN based on a DRB on which UL data can be made available in the WTRU. For example, the WTRU can be configured to use an SCG DRB or a DRB for which the SN is terminated. The WTRU can determine to execute a resume procedure for the SN when UL data becomes available for the DRB. The WTRU can execute a resume procedure for the MN (e.g., the PCell) when data arrives for another DRB. The WTRU can execute a resume procedure for the SN when the WTRU is configured to use a split DRB. The WTRU can execute a resume procedure for the SN when the data arriving at the WTRU is for the split DRB.

[0139] The WTRU can execute a resume procedure with the SN in response to a paging message. As described herein, the paging message can indicate that DL data is available to the WTRU on an SCG DRB or a DRB for which the SN is terminated.

[0140] The WTRU can execute a resume procedure with the SN based on the characteristics of the data that becomes available for transmission. For example, the WTRU can receive data having different QoS requirements (e.g., eMBB vs. URLLC). If the WTRU supports the QoS requirements, the WTRU can directly execute a resume for the SN.

[0141] The WTRU can execute a resume procedure with the SN based on the closure status on the MN. For example, the WTRU may be rejected (e.g., due to NW congestion) during a resume procedure for the MN. In response to a rejected resume procedure for the MN, the WTRU can attempt a resume procedure for the SN.

[0142] The WTRU can execute a resume procedure with the SN based on measurements of the PCell / PSCell. The WTRU can directly execute a resume procedure for the SN when the DL cell quality of the SN exceeds a threshold. Also, or alternatively, the WTRU can directly execute a resume procedure for the SN when the SN quality measurement value is better than the MN quality measurement value. For example, the measurement values can be maintained by the WTRU while in the RRC_INACTIVE state.

[0143] The WTRU can execute a resume procedure with the SN based on the bearer configuration for which UL data has arrived for the WTRU. For example, the WTRU can initiate a resume procedure for the SN when it receives data for a bearer (e.g., an SCG bearer or a split UL bearer) through which the WTRU can route traffic via the SN. The WTRU cannot initiate a resume procedure for the SN when it receives data for a bearer through which the WTRU cannot route traffic via the SN.

[0144] The WTRU can execute a resume procedure with the SN based on key material. The WTRU can be configured to use the key material for the SN when the WTRU was last suspended. The WTRU can initiate a resume procedure for the SN if it was configured to use the key material for the SN when the WTRU was last suspended.

[0145] The WTRU can reconfigure a bearer.

[0146] As described herein, the WTRU can execute a resume procedure with the SN. The WTRU can assume the role of the MN, and the SN is changed at the start of the resume procedure and / or during the resume procedure. The WTRU can determine the DRB / SRB routing based on the role change. For example, after the role change, the WTRU can route data from the MCG DRB to the previous SN (e.g., the new MN). The WTRU can route data from the SCG DRB to the previous MN (e.g., the new SN). The bearer reconfiguration of the WTRU can be applied to the SRB (e.g., can be applied only to the SRB). For example, the SN can assume the role of the MN, and the WTRU can reconfigure the DRB so that the DRB path is not changed. The WTRU can reconfigure and / or relocate the SRB. For example, the WTRU can reconfigure SRB1 (which could be routed through the previous MN) to be routed to the new MN (e.g., the previous SN). The WTRU can reconfigure SRB1 starting from resume to the new MN. The WTRU can reconfigure SRB3 to be routed to the old MN (e.g., the new SN).

[0147] The WTRU can change the MR-DC configuration. The WTRU can change the MR-DC configuration during the resume procedure for the SN. For example, a WTRU within NG-EBDC (e.g., MCG in LTE, SCG in NR) can reconfigure itself to use NE-DC (e.g., MCG in NR, SCG in LTE).

[0148] The WTRU can determine a lower layer configuration for the SCG. For example, the WTRU can release the lower layer (PHY, MAC, RLC) configuration of the SCG and maintain the bearer / PDCP configuration when the WTRU transitions to the RRC_INACTIVE state. Reconfiguration of the lower layers (e.g., signaling overhead associated with a transition to the RRC_CONNECTED state) may not be performed (e.g., skipped). The lower layers of the WTRU can be reconfigured for a particular SCell (e.g., when the WTRU needs to access the SCell).

[0149] The WTRU can receive a pre - defined (e.g., dedicated) configuration for the SCG via signaling. One or more configurations (e.g., pre - defined dedicated configurations) that can be used in a given SCell can be provided to the WTRU. Such pre - defined dedicated configurations can be associated with lower layer configurations, such as PHY, MAC, or RLC layer configurations. Such pre - defined dedicated configurations can be associated with higher layer configurations, such as PDCP and / or radio bearer configurations. The configurations (e.g., each pre - defined configuration) can be associated with an index that can be transmitted (e.g., in the transmitted configuration). The WTRU can receive such pre - defined dedicated configurations via RRC signaling while the WTRU is in the RRC_CONNECTED state and / or as part of the RRC signaling to transition the WTRU to the RRC_INACTIVE state. Additionally, or alternatively, the WTRU can receive the pre - defined dedicated configurations via RRC signaling directly on an SRB (e.g., SRB3 configured in the SN). When the WTRU is in the RRC_INACTIVE state, the WTRU can receive an index of the dedicated configuration to apply to a given SCell and / or the WTRU can apply the associated configurations for any operation to each SN SCell while the WTRU is in the RRC_INACTIVE state. The WTRU can apply each configuration to the SN Scell for one or more of, without limitation, data transmission while the WTRU remains in the RRC_INACTIVE state, RACH procedures for the SCell, measurements, and / or SI reception.

[0150] The WTRU can receive, in the SI broadcast by the SCell, the dedicated configuration applied to the SCell. The WTRU can monitor the SI in the SCell and receive an index that can indicate the dedicated configuration applied to that cell. The WTRU can receive the dedicated configuration applied to an SCell within a list of index / Scell pairs transmitted in the SI of the PCell (e.g., via broadcast and / or provided on demand). A configuration (e.g., a single configuration) that the WTRU can apply to a set of SCells (e.g., all SCells within an SCell list) can be provided to the WTRU.

[0151] The WTRU can use the default configuration for the SCell. A default dedicated configuration used for one or more SCells (e.g., across all SCells) can be provided to the WTRU. The default configuration can be preconfigured in the WTRU with specific values or provided by the MN via RRC signaling or SI. The default configuration can be applied to specific operations (e.g., data transmission, or RACH procedures to obtain timing alignment) while the WTRU is in the RRC_INACTIVE state (e.g., only to those), and also under certain conditions (e.g., only under certain conditions), such as when the amount of data transmitted while in the RRC_INACTIVE state is less than a threshold and / or when the type of data transmitted has a certain characteristic related to the transmission latency, reliability, and / or size. When the default configuration is applied, the WTRU can access (e.g., directly access) the SCell while in the RRC_INACTIVE state. If the conditions are not met, the WTRU can initiate procedures to transition to the RRC_CONNECTED state.

[0152] The WTRU can obtain a dedicated configuration to resume access to the SCell. The WTRU can initiate procedures for the SCell by utilizing a default configuration (e.g., the received default configuration as described herein) to obtain a dedicated configuration (e.g., a non-default one) to be used in the SCell. The WTRU can perform a RACH procedure, exchange RRC messages with the SCell while in the RRC_INACTIVE state, and / or receive a dedicated configuration (e.g., as part of signaling) to be used for further access to that SCell. The WTRU can perform subsequent access to the SCell (e.g., for data transmission) using the received non-default (e.g., dedicated) configuration.

[0153] The WTRU can invalidate the received non-default configuration as a result of one or more of the following, i.e., expiration of a timer, receipt of a paging message instructing the WTRU to invalidate the received non-default configuration, reselection to a different cell associated with the MN such that one or more SCell(s) become better / worse than one or more other SCell(s), a measurement related event, when the WTRU transitions to the RRC_CONNECTED state, and / or as part of signaling to transition to the RRC_CONNECTED state, etc., as indicated by the network that the WTRU should invalidate the received non-default configuration. The WTRU can receive a list of SCell(s) for which the configuration can be valid (e.g., can also be valid for it) upon receipt of the dedicated (non-default) configuration.

[0154] Figures 2 and 3 illustrate examples associated with a WTRU receiving DL data on an SCG cell while remaining in the RRC_INACTIVE state.

[0155] Figure 2 illustrates an example associated with WTRU mobility. As illustrated in Figure 2, the WTRU can communicate with a network (e.g., a 5G CN) via an MCG bearer and / or an MN. The WTRU can communicate with the network via an SCG bearer. The SCG bearer can be associated with an SN and / or one or more SCG cells (e.g., SCG cell list 1 and / or SCG cell list 2). As illustrated in Figure 2, the WTRU can be configured to use an SCG list (e.g., SCG cell list 1). The WTRU can be configured to use the SCG list while in the RRC_CONNECTED state or during a transition from the RRC_CONNECTED state to the RRC_INACTIVE state. The WTRU can be configured to use the SCG list via an MCG bearer and / or an MN. The WTRU can move around (e.g., perform mobility) while in the RRC_INACTIVE state as long as the WTRU remains within the coverage (e.g., coverage conditions) of the cells on the SCG list. The coverage conditions can be defined as the WTRU having at least one of the cells on the SCG list measured (e.g., using a quality metric) as exceeding a threshold (e.g., a configured threshold). When the WTRU moves outside the coverage of the list configured according to the coverage conditions (e.g., based on the quality metrics for all cells on the SCG list being measured as below the threshold), the WTRU can initiate a transition to the RRC_CONNECTED state. When the WTRU transitions to the RRC_CONNECTED state, the WTRU can be configured to use a new SCG list (e.g., SCG cell list 2 as illustrated in Figure 2). After receiving the new SCG list, the WTRU can transition to the RRC_INACTIVE state (e.g., transition immediately).

[0156] Figure 3 illustrates an example associated with a WTRU that receives data from a cell while in the RRC_INACTIVE state. As illustrated in Figure 3, the WTRU can communicate with a network (e.g., 5G CN) via the MCG bearer and / or the MN. The WTRU can communicate with the network via the SCG bearer. The SCG bearer can be associated with the SN and / or one or more SCG cells. Also, or alternatively, the SN can communicate with the MN. As illustrated in Figure 3, data for the WTRU can arrive at the SCG bearer and / or the SN. The SN can indicate the arrival of the data to the MN. Indicating the arrival of data on the SCG can trigger the MN to send a paging message. For example, the paging message can be sent to the WTRU via the MCG and / or can indicate that data is available to the WTRU on the SCG bearer. The paging message can indicate that the WTRU should perform a RACH on another cell (e.g., a cell on the SCG list). As illustrated in Figure 3, the WTRU can receive a paging message, for example, while in the RRC_INACTIVE state. Upon receiving the paging message, the WTRU can select a cell from the SCG list (e.g., the currently configured SCG list). For example, the WTRU can determine and select the best cell within the SCG list. Upon such a determination, the WTRU can perform a RACH procedure for the selected cell and can receive data during the RACH procedure (e.g., MSG4) and / or at another time after the RACH procedure (e.g., by decoding the PDCCH of the selected cell during a period of time).

[0157] Systems, methods, and means for operating dual connectivity (DC) in an inactive state are disclosed. System information (SI) for a DC configuration applicable to the INACTIVE state can be provided. A wireless transmit / receive unit (WTRU) can transition to RRC_CONNECTED or perform an area update procedure in an INACTIVE state DC configuration, for example, based on a secondary node (SN) mobility related trigger, for example, for a list of potential primary / secondary cells (PSCells). The procedure can support measurement events related to the list of potential PSCs. The WTRU can report SN related measurement information and indications for context update / removal, for example, during a state transition or area update. The WTRU can receive paging and can initiate (e.g., directly) downlink (DL) data transmission from the SN. The WTRU can transmit control / data (e.g., associated trigger conditions) to the SN (e.g., directly) while in RRC_INACTIVE.

[0158] The processes and means described herein can be applied in any combination and can be applied to other wireless technologies and to other services.

[0159] The WTRU may refer to the identity of a physical device or a subscription related identity (identification), e.g., an MSISDN, a SIP URI, etc., the identity of a user. The WTRU may refer to an application based identity, e.g., a username that can be used for each application.

[0160] Each computing system described herein can have one or more computer processors having a memory configured to have executable instructions, or hardware for achieving the functions described herein including determining the parameters described herein and transmitting and receiving messages between entities (e.g., WTRUs and networks) to achieve the functions described herein.

[0161] The processes described above can be implemented by a computer program, software, and / or firmware included in a computer-readable medium and executed by a computer and / or processor. Examples of computer-readable media include, without limitation, electronic signals (transmitted over wired and / or wireless connections), and / or computer-readable storage media. Examples of computer-readable storage media include, without limitation, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks without limitation, magneto-optical media, and / or optical media such as CD-ROM disks and / or digital versatile disks (DVD). A processor associated with software can be used to implement radio frequency transceivers used in WTRUs, terminals, base stations, RNCs, and / or any host computer.

Description of Reference Numerals

[0162] 100 Communication system 102a Radio transceiver unit 102b Radio transceiver unit 102c Radio transceiver unit 102d Radio transceiver unit 108 Public switched telephone network 110 Internet 112 Network 114a Base station 114b Base Station 116 Air Interface 118 Processor 120 Transceiver 122 Receiver Element 124 Microphone 126 Keypad 128 Touch Pad 130 Non-Removable Memory 132 Removable Memory 134 Power Supply 136 GPS Chipset 136 Chipset 138 Peripheral Devices 139 Interference Management Unit 160b eNode 160c eNode 162 Mobility Management Entity 164 Serving Gateway 166 Gateway 182a Mobility Management Function 182b Mobility Management Function 183a Session Management Function 183b Session Management Function 184a User Plane Function 184b User Plane Function 185a Data Network 185b Data Network

Claims

1. 1. A wireless transmit / receive unit (WTRU), comprising: receiving configuration information during a procedure of transitioning the WTRU from a connected state to an inactive state, in which the WTRU is configured to maintain an Access Stratum (AS) context, the configuration information indicating a list of cells on which to perform respective measurements, provided that the WTRU is associated with an inactive mode; performing measurements in cells from the list of cells while the WTRU is associated with the inactive state, the cells corresponding to cells that can be supported by the WTRU as secondary cells if the WTRU transitions to a connected state; performing a resumption procedure, the performing the resumption procedure including transitioning the WTRU from the inactive state to the connected state, and transmitting results of the measurements to a base station during the resumption procedure that transitions the WTRU from the inactive state to the connected state. Processor configured to A WTRU comprising:

2. 2. The WTRU of claim 1, wherein the cell is a Secondary Cell Group (SCG) cell.

3. The processor, determining to perform the measurement in the cell based on whether a time period has expired or not; 2. The WTRU of claim 1, further configured to:

4. The processor, ceasing to perform said measurements in said cell upon a condition that said time period has expired; performing said measurement in said cell on the condition that said time period has not expired. The WTRU of claim 3 , further configured to:

5. 2. The WTRU of claim 1, wherein the configuration information further includes one or more of carrier frequency information, cell bandwidth information, reference signal (RS) configuration information, measurement configuration information, event configuration information, information associated with a primary cell (PCell), or information associated with a list of SCG cells on which the measurements are performed.

6. 2. The WTRU of claim 1, wherein the configuration information comprises a system information (SI) message or a system information block (SIB) message.

7. 2. The WTRU of claim 1, wherein the inactive state comprises an RRC_INACTIVE state and the connected state comprises an RRC_CONNECTED state.

8. 1. A method performed by a wireless transmit / receive unit (WTRU), comprising: receiving configuration information during a procedure of transitioning the WTRU from a connected state to an inactive state, in which the WTRU is configured to maintain an Access Stratum (AS) context, the configuration information indicating a list of cells on which to perform respective measurements, provided that the WTRU is associated with an inactive mode; performing measurements on cells from the list of cells while the WTRU is associated with the inactive state, the cells corresponding to cells that can be supported by the WTRU as secondary cells when the WTRU transitions to a connected state; performing a resumption procedure, the performing the resumption procedure including transitioning the WTRU from the inactive state to the connected state, and transmitting results of the measurements to a base station during the resumption procedure that transitions the WTRU from the inactive state to the connected state; 23. A method comprising:

9. 10. The method of claim 8, wherein the cell is a secondary cell group (SCG) cell.

10. determining to perform the measurements in the cell based on whether a time period has expired or not; 9. The method of claim 8, further comprising:

11. ceasing to perform said measurements in said cell on condition that said time period has expired; performing said measurements in said cell on the condition that said time period has not expired. The method of claim 10 further comprising:

12. 9. The method of claim 8, wherein the configuration information further comprises one or more of carrier frequency information, cell bandwidth information, reference signal (RS) configuration information, measurement configuration information, event configuration information, information associated with a primary cell (PCell), or information associated with a list of SCG cells on which the measurements are performed.

13. 9. The method of claim 8, wherein the configuration information comprises a system information (SI) message or a system information block (SIB) message.

14. 9. The method of claim 8, wherein the inactive state comprises an RRC_INACTIVE state and the connected state comprises an RRC_CONNECTED state.

15. 1. A method performed by a base station, comprising: transmitting configuration information during a procedure of transitioning a wireless transmit / receive unit (WTRU) from a connected state to an inactive state, wherein in the inactive state the WTRU is configured to maintain an access stratum (AS) context, the configuration information indicating a list of cells on which to perform respective measurements, provided that the WTRU is associated with an inactive mode; initiating a procedure to transition the WTRU from the inactive state to the connected state; receiving measurement results associated with the list of cells, the measurement results associated with the list of cells including measurements performed while the WTRU was associated with the inactive state; 23. A method comprising:

16. 16. The method of claim 15, wherein the received measurements associated with the list of cells include measurements on Secondary Cell Group (SCG) cells.

17. 16. The method of claim 15, wherein the configuration information further comprises one or more of carrier frequency information, cell bandwidth information, reference signal (RS) configuration information, measurement configuration information, event configuration information, information associated with a primary cell (PCell), or information associated with a list of SCG cells on which the measurements are performed.

18. 16. The method of claim 15, wherein the configuration information comprises a system information (SI) message or a system information block (SIB) message.

19. 16. The method of claim 15, wherein the inactive state comprises an RRC_INACTIVE state and the connected state comprises an RRC_CONNECTED state.

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