Connection establishment and recovery in multi-layer network

Abstract

Systems, methods, and instrumentalities for connection, establishment, and recovery in a multi-layer network are described herein. A wireless transmit / receive unit (WTRU) may be configured to be associated with a first cell of a first network layer. The WTRU may receive configuration information indicating that a first network layer is associated with a first connection cause and a second network layer is associated with a second connection cause. The WTRU may determine to establish the connection, and may determine an associated connection cause for establishing the connection. In an example, the associated connection cause may be a second connection cause. The WTRU may perform cell reselection on the second cell based on the first cell being associated with the first connection cause, the second cell being associated with the second connection cause, and the second cell being available. The WTRU may establish a connection via the second cell.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 395,543, filed on August 5, 2022, the disclosure of which is incorporated herein by reference in its entirety. Background Art

[0003] Mobile communications using wireless communications continue to evolve. The fifth generation may be referred to as 5G. Previous (legacy) mobile communications may be, for example, fourth generation (4G) Long Term Evolution (LTE). Summary of the invention

[0004] Systems, methods, and means are described herein for connection, establishment, and recovery in a multi-layer network.

[0005] A wireless transmit / receive unit (WTRU) may be configured to associate (e.g., camp on) a first cell of a first network layer. When in an RRC_IDLE / RRC_ACTIVE state, the WTRU may camp on the first cell according to a traditional cell reselection behavior. The WTRU may receive configuration information. The configuration information may indicate that the first network layer is associated with a first connection cause and the second network layer is associated with a second connection cause. In an example, the WTRU may be configured with a mapping of connection cause values ​​(e.g., a first connection cause value and a second connection cause value) and a preferred layer of a network (e.g., TN, LEO, MEO, GEO, etc.). In an example, the first network layer may be a non-terrestrial network (NTN) and the second network layer may be a terrestrial network (TN).

[0006] The WTRU may determine to establish a connection and may determine an associated connection reason for establishing the connection. In an example, establishing the connection may include establishing or resuming a connection. The associated connection reason may be related to at least one of: an emergency call; a mobile originated data call; a mobile originated voice call; or a mobile originated SMS.

[0007] In an example, the associated connection cause may be a second connection cause. Based on the first cell being associated with a first network type and the first network type being associated with the first connection cause (e.g., the first cell is not a preferred network type for the determined associated connection cause (e.g., the second connection cause)), the second cell being associated with a second network type and the second network being associated with the second connection cause (e.g., the second cell is a preferred network type for the determined associated connection cause (e.g., the second connection cause), and the second cell being available, the WTRU may perform cell reselection on the second cell. The WTRU may (e.g., may then) establish a connection via the second cell.

[0008] The WTRU may (e.g., may further) be configured to send an indication to the network regarding the cell reselection performed. In an example, the indication may include information regarding the association establishment cause and information that the WTRU was camped on the NTN and was reselected to the TN due to the association establishment cause. The information may be indicated in one or more of the following ways: in a SETUP / RESTORATION REQUEST message; in a SETUP / RESTORATION COMPLETE message; in an RRC message after the SETUP / RESTORATION is complete (e.g., WTRU Assistance Information); or in mobility history information (e.g., the mobility history information may be autonomously sent by the WTRU to the network or requested from the network). BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented;

[0010] Figure 1B is an example of an embodiment in which Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within an illustrated communication system;

[0011] Figure 1C is an example of an embodiment in which Figure 1A A system diagram of an example Radio Access Network (RAN) and an example Core Network (CN) used within the illustrated communication system;

[0012] Figure 1D is an example of an embodiment in which Figure 1A A system diagram of another example RAN and another example CN used within the illustrated communication system;

[0013] Figure 2 An example of a radio resource control (RRC) connection establishment, setup and / or connection recovery procedure starting from an idle state is illustrated, and the idle state may be an RRC_IDLE state.

[0014] Figure 3 An example of recovering an RRC connection from an inactive state is illustrated, and the inactive state may be an RRC_INACTIVE state.

[0015] Figure 4 Examples of different states, such as RRC states, and one or more transitions therebetween are illustrated.

[0016] Figure 5A and Figure 5B An example of a cell selection and / or reselection procedure in a network is illustrated.

[0017] Figure 6An example of multiple interfaces in a network, which may be a non-terrestrial network, is illustrated.

[0018] Figure 7 An exemplary scenario is illustrated in which a WTRU may be connected to multiple layers, where the multiple layers may belong to one or more networks (eg, a terrestrial network (TN) and several layers of NTN).

[0019] Figures 8 to 9 An example of cell reselection based on establishment cause is illustrated. DETAILED DESCRIPTION

[0020] Figure 1A 1 is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through sharing of system resources (including wireless bandwidth). For example, the communication system 100 may employ 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 multi-carrier (FBMC), etc.

[0021] like Figure 1AAs shown, the communication system 100 may 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, but it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the UE 102a, 102b, 102c, 102d (any of which may be referred to as a “station” and / or “STA”) may be configured to send and / or receive wireless signals and may include a user equipment (WTRU), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated process chain environment), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0022] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device that is configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNode B, a Home Node B, a Home eNode B, a gNB, an NR Node B, a site controller, an access point (AP), a wireless router, and the like. Although the base stations 114a, 114b are each depicted as a single element, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0023] Base station 114a may be part of RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as base station controllers (BSC), radio network controllers (RNC), relay nodes, etc. Base station 114a and / or base station 114b may be configured to send and / or receive wireless signals on one or more carrier frequencies (which may be referred to as cells (not shown)). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of a licensed spectrum and an unlicensed spectrum. A cell may provide coverage of wireless services to a specific geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Therefore, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In an embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to send and / or receive signals in a desired spatial direction.

[0024] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0025] More specifically, as noted above, the communication system 100 may be a multiple access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 115 / 116 / 117. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0026] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA) that may establish the air interface 116 using Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-APro).

[0027] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0028] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may together implement LTE radio access and NR radio access, for example using the dual connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions transmitted to / from multiple types of base stations (e.g., eNBs and gNBs).

[0029] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (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 rates for GSM Evolution (EDGE), and GSM EDGE (GERAN).

[0030] Figure 1AThe base station 114b in may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in local areas such as commercial venues, homes, vehicles, campuses, industrial facilities, sky corridors (e.g., for use by drones), and roads. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio 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 may implement a radio 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 may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or a femtocell. As Figure 1A As shown, base station 114b may have a direct connection to Internet 110. Therefore, base station 114b may not need to access Internet 110 via CN 106 / 115.

[0031] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, applications and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not described in detail in the text and video, the CN 106 / 115 may be configured to provide voice, data, applications and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Figure 1A Although not shown in the figure, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0032] The CN 106 / 115 may also act as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global 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) in the TCP / IP Internet protocol suite. The networks 112 may include wired communication networks and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0033] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0034] Figure 1B is a system diagram illustrating an example WTRU 102. Figure 1B As shown, the WTRU 102 may 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, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0035] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated 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 state machine, etc. The processor 118 may perform signal decoding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, but it is understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0036] The send / receive element 122 may be configured to send a signal to a base station (e.g., base station 114a) or receive a signal from a base station via an air interface 116. For example, in one embodiment, the send / receive element 122 may be an antenna configured to send and / or receive an RF signal. In an embodiment, the send / receive element 122 may be a transmitter / detector configured to send and / or receive, for example, an IR, UV, or visible light signal. In another embodiment, the send / receive element 122 may be configured to send and / or receive both an RF signal and an optical signal. It should be understood that the send / receive element 122 may be configured to send and / or receive any combination of wireless signals.

[0037] Although the transmit / receive element 122 Figure 1B Although depicted as a single element in the figure, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0038] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. For example, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0039] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store data in any type of suitable memory, such as a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may 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 may access information from and store data in a memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0040] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel cadmium (NiCd), nickel zinc (NiZn), nickel metal hydride (NiMH), lithium ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0041] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or in lieu of the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by any suitable location-determination method while remaining consistent with an embodiment.

[0042] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic 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, module, FM radio unit, digital music player, media player, video game player module, Internet browser, virtual reality and / or augmented reality (VR / AR) device and activity tracker, etc. Peripheral device 138 may include one or more sensors, which may be one or more of the following: gyroscope, accelerometer, Hall effect sensor, magnetometer, orientation sensor, proximity sensor, temperature sensor, time sensor; geolocation sensor; altimeter, light sensor, touch sensor, magnetometer, barometer, gesture sensor, biometric sensor and / or humidity sensor.

[0043] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for both UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference via hardware (e.g., a choke) or via signal processing performed by a processor (e.g., a separate processor (not shown) or via the processor 118). In one embodiment, the WRTU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for both UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0044] Figure 1C 1 is a system diagram illustrating the RAN 104 and the CN 106 in accordance with an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0045] The RAN 104 may include evolved Node-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of evolved Node-Bs while remaining consistent with an embodiment. The evolved Node-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the evolved Node-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the evolved Node-B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0046] Each of the evolved Node Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, and scheduling of users in the UL and / or DL, among other things. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0047] Figure 1C The illustrated CN 106 may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements is depicted as being part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0048] The MME 162 may be connected to each of the evolved Node-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, and selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0049] The SGW 164 may be connected to each of the evolved Node-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during an inter-evolved Node-B handover, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0050] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0051] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may be in communication with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers.

[0052] Although the WTRU Figures 1A to 1D Although described as wireless terminals, it is contemplated that in certain representative embodiments, such terminals may (eg, temporarily or permanently) use a wired communications interface with a communications network.

[0053] In a representative embodiment, the other network 112 may be a WLAN.

[0054] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for a BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic to and / or out of the BSS. Traffic originating from outside the BSS and destined for the STA may be reached by the AP and may be delivered to the STA. Traffic originating from the STA and destined for a target outside the BSS may be transmitted to the AP to be delivered to the corresponding target. Traffic between STAs within the BSS may be transmitted by the AP, for example, wherein the source STA may transmit traffic to the AP, and the AP may deliver traffic to the target STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. Point-to-point traffic may be transmitted between the source STA and the target STA (e.g., directly between them) using a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (eg, all STAs in the STA) may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad hoc" communication mode.

[0055] When using the 802.11ac infrastructure operation mode or a similar operation mode, the AP may send beacons on a fixed channel (such as a primary channel). The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a width dynamically set via signaling. The primary channel may be an operating channel of the BSS and may be used by the STA to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access / collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. For CSMA / CA, a STA (e.g., each STA) (including the AP) may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0056] High throughput (HT) STAs may communicate using a 40 MHz wide channel (eg, via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels) to form a 40 MHz wide channel.

[0057] Very high throughput (VHT) STA can support 20MHz, 40MHz, 80MHz and / or 160MHz wide channels. 40MHz channels and / or 80MHz channels can be formed by combining continuous 20MHz channels. 160MHz channels can be formed by combining 8 continuous 20MHz channels, or by combining two non-continuous 80MHz channels (this can be called 80+80 configuration). For 80+80 configuration, after channel coding, the data can pass through a segment parser that can divide the data into two streams. Each stream can be processed by inverse fast Fourier transform (IFFT) and time domain processing separately. These streams can be mapped to two 80MHz channels, and the data can be sent by sending STA. At the receiver of the receiving STA, the above-mentioned operation for 80+80 configuration can be reversed, and the combined data can be transmitted to the medium access control (MAC).

[0058] 802.11af and 802.11ah support operating modes below 1GHz. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah relative to those used in 802.11n and 802.11ac. 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support instrument type control / machine type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only support for) certain bandwidths and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain very long battery life).

[0059] 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 may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA (which supports the minimum bandwidth operating mode) from all STAs operating in the BSS. In the example of 802.11ah, for STAs (e.g., MTC-type devices) that support (e.g., only support) a 1MHz mode, the primary channel may be 1MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because a STA (supporting only a 1MHz operating mode) is sending to the AP, the entire available band may be considered busy even if most of the band remains idle and may be available.

[0060] In the United States, the available frequency band for 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

[0061] Figure 1D 1 is a system diagram illustrating the RAN 113 and the CN 115 in accordance with an embodiment. As noted above, the RAN 113 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0062] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 108b may utilize beamforming to send signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a may, for example, use multiple antennas to send wireless signals to and / or receive wireless signals from the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In an embodiment, gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0063] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with parameter sets that may be scalable. For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmit time intervals (TTIs) of varying or scalable lengths (e.g., containing different numbers of OFDM symbols and / or varying absolute time lengths over time).

[0064] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c while not accessing other RANs (e.g., such as the eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may use one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect with the gNB 180a, 180b, 180c while also communicating / connecting with another RAN, such as the eNodeB 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNodeBs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNodeB 160a, 160b, 160c may act as a mobility anchor for the WTRUs 102a, 102b, 102c, and the gNB 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0065] Each of the gNBs 180a, 180b, 180c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, support of network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards a user plane function (UPF) 184a, 184b and routing of control plane information towards an access and mobility management function (AMF) 182a, 182b, etc. Figure 1D As shown, gNBs 180a, 180b, and 180c may communicate with each other via an Xn interface.

[0066] Figure 1DThe illustrated CN 115 may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and possible data networks (DNs) 185a, 185b. Although each of the foregoing elements is depicted as part of the CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0067] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, support of network slicing (e.g., handling of different PDU sessions with different requirements), selecting a specific SMF 183a, 183b, management of registration areas, termination of NAS signaling, mobility management, etc. The AMF 182a, 182b may use network slicing in order to customize CN support for the WTRU 102a, 102b, 102c based on the type of services utilized by the WTRU 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced mobile broadband (eMBB) access, and / or services for machine type communication (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0068] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b, and configure traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0069] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, and providing mobility anchoring, etc.

[0070] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b via the UPF 184a, 184b via an N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0071] Given that Figures 1A to 1D as well as Figures 1A to 1D Corresponding to the description of the present invention, one or more or all of the functions described herein with reference to one or more of the following may be performed by one or more simulation devices (not shown): WTRU102a-d, base station 114a-b, evolved Node B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b and / or any other device described herein. The simulation device may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the simulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0072] The simulation device may be designed to implement one or more tests of other devices in a laboratory environment and / or in an operator network environment. For example, one or more simulation devices may perform one or more functions or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. One or more simulation devices may perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device may be directly coupled to another device for testing purposes and / or may use over-the-air wireless communications to perform testing.

[0073] One or more simulation devices can perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test scenario in a test laboratory and / or a non-deployed (e.g., testing) wired and / or wireless communication network to implement testing of one or more components. One or more simulation devices can be test equipment. Direct RF coupling and / or wireless communication via RF circuits (e.g., which can include one or more antennas) can be used by the simulation device to send and / or receive data.

[0074] References to timers herein may refer to a determination of a time or a determination of a time period. References to expiration of a timer herein may refer to a determination that a time has occurred or a time period has expired. References to timers herein may refer to a time, a time period, tracking a time, tracking a time period, etc. References to legacy technology or legacy handover may refer to a legacy technology such as LTE compared to NR, or a legacy version of a technology, for example, an older version / release of a technology (e.g., an older NR release) compared to a newer version / release of the technology (e.g., a newer NR release).

[0075] Systems, methods, and means are described herein for connection, establishment, and recovery in a multi-layer network.

[0076] A wireless transmit / receive unit (WTRU) may be configured to associate (e.g., camp on) a first cell of a first network layer. When in an RRC_IDLE / RRC_ACTIVE state, the WTRU may camp on the first cell according to a traditional cell reselection behavior. The WTRU may receive configuration information. The configuration information may indicate that the first network layer is associated with a first connection cause and the second network layer is associated with a second connection cause. In an example, the WTRU may be configured with a mapping of connection cause values ​​(e.g., a first connection cause value and a second connection cause value) and a preferred layer of a network (e.g., TN, LEO, MEO, GEO, etc.). In an example, the first network layer may be a non-terrestrial network (NTN) and the second network layer may be a terrestrial network (TN).

[0077] The WTRU may determine to establish a connection and may determine an associated connection reason for establishing the connection. In an example, establishing the connection may include establishing or resuming a connection. The associated connection reason may be related to at least one of: an emergency call; a mobile originated data call; a mobile originated voice call; or a mobile originated SMS.

[0078] In an example, the associated connection cause may be a second connection cause. Based on the first cell being associated with a first network type and the first network type being associated with the first connection cause (e.g., the first cell is not a preferred network type for the determined associated connection cause (e.g., the second connection cause)), the second cell being associated with a second network type and the second network being associated with the second connection cause (e.g., the second cell is a preferred network type for the determined associated connection cause (e.g., the second connection cause), and the second cell being available, the WTRU may perform cell reselection on the second cell. The WTRU may (e.g., may then) establish a connection via the second cell.

[0079] The WTRU may (e.g., may further) be configured to send an indication to the network regarding the cell reselection performed. In an example, the indication may include information regarding the association establishment cause and information that the WTRU was camped on the NTN and was reselected to the TN due to the association establishment cause. The information may be indicated in one or more of the following ways: in a SETUP / RESTORATION REQUEST message; in a SETUP / RESTORATION COMPLETE message; in an RRC message after the SETUP / RESTORATION is complete (e.g., WTRU Assistance Information); or in mobility history information (e.g., the mobility history information may be autonomously sent by the WTRU to the network or requested from the network).

[0080] The WTRU may be configured to perform cell reselection on a cell belonging to a network layer (e.g., terrestrial network (TN), non-terrestrial network (NTN), etc.) based on a connection establishment cause during connection establishment. The WTRU may be configured to perform cell reselection on a cell belonging to a network layer (e.g., TN, NTN, etc.) based on a connection recovery cause during connection recovery. The WTRU may be configured to perform cell reselection on a cell belonging to a network layer (e.g., TN, NTN, etc.) based on an access category / identity cause during connection establishment. The WTRU may be configured to perform cell reselection on a cell belonging to a network layer (e.g., TN, NTN, etc.) based on an access category / identity cause during connection recovery. The WTRU may be configured to perform simultaneous camping on multiple cells at different layers (e.g., TN, NTN, etc.). During connection establishment / recovery, the WTRU may select / pick the cell on which the WTRU camps based on connection establishment / recovery or access category / identity.

[0081] As used herein, "establish" and "establish" may be used interchangeably. For example, connection establishment may be equivalent to connection establishment, and vice versa. As another example, establishment reason may be equivalent to establishment reason. As used herein, "establishment reason", "connection reason", "connection establishment reason", and "associated connection reason" may be used interchangeably. As used herein, "network layer" and "network type" may be used interchangeably. For example, network type may be equivalent to network layer, and vice versa.

[0082] A WTRU (e.g., operating in RRC_IDLE / RRC_INACTIVE) may be able to connect to multiple cells associated with a multi-layer network (e.g., a terrestrial network, a non-terrestrial network, etc.). Each respective cell in the plurality of cells may be associated with a respective network layer (e.g., a first cell may be associated with a first network layer, and a second cell may be associated with a second network layer). The WTRU may (e.g., be configured to) select a cell associated with a network layer during connection establishment / restore (e.g., select the correct cell / appropriate cell) based on the suitability of the network layer / cell. The suitability of the network layer / cell may be based on a connection establishment / restore reason (e.g., a connection reason) and / or an access identity / category. For example, the WTRU may receive configuration information (e.g., configuration / mapping) indicating a connection reason (e.g., an establishment / restore reason (e.g., emergency, mo-Data, mo-VoiceCall, mo-SMS, etc.)), an access identity / category, and / or a network layer (e.g., TN, NTN, etc.). The configuration information may indicate that respective network layers are associated with respective connection reasons (e.g., a first network layer is associated with a first connection reason, and a second network layer is associated with a second connection reason), e.g., as described herein and shown in the accompanying drawings (e.g., Figure 8 ).

[0083] The WTRU may be associated with (e.g., camp on) a cell (e.g., a first cell, e.g., a best cell). For example, the WTRU may camp on a cell (e.g., a first cell) based on a traditional cell reselection behavior (e.g., when in RRC_IDLE / RRC_INACTIVE). For example, a connection may be established or restored due to UL data. An establishment cause may be determined to establish a connection to the cell. The establishment cause may be a connection cause (e.g., a first connection cause or a second connection cause). If the current serving cell (e.g., the first cell) belongs to a network layer (e.g., a first network) that is configured to be preferred for a connection establishment / restoration cause (e.g., a first connection cause), an access identity, and / or an access category, then a connection may be established / restored via the cell by initiating a RACH process to the current serving cell (e.g., the first cell), etc. If there is a suitable (e.g., available) neighboring cell (e.g., the second cell) belonging to the network layer (e.g., the second network layer), which is configured as suitable for the connection establishment / restore cause (e.g., the second connection cause) or the access identity / category (e.g., as indicated in the configuration information), a cell reselection to the neighboring cell (e.g., the second cell) may be performed / established, or a connection may be established / restored (e.g., via the selected neighboring cell). The connection may (e.g., otherwise) be established / restored via the current serving cell (e.g., the first cell).

[0084] In an example, a WTRU operating in RRC_IDLE / RRC_INACTIVE may be able to connect to multiple multi-layer networks (e.g., terrestrial networks, non-terrestrial networks, etc.). The WTRU may (e.g., be configured to) camp on multiple cells in different layers simultaneously (e.g., concurrently). The WTRU may (e.g., be configured to) select a cell (e.g., a correct cell) among the multiple cells for connection establishment / resumption based on the connection establishment / resumption cause and / or access identity / category.

[0085] Examples of connection states and / or state transfers are provided herein. Examples of RRC connection states and state transitions are provided herein. In a network (e.g., an NR network), a WTRU may be in one or more states, such as one of the following RRC states: RRC_CONNECTED (e.g., which may be referred to as "CONNECTED mode"); RRC_INACTIVE (e.g., which may be referred to as "INACTIVE mode"); and / or RRC_IDLE (e.g., which may be referred to as "IDLE mode").

[0086] In a connected state (such as the RRC_CONNECTED state), the WTRU may actively connect to the network, establish signaling and data radio bearers (e.g., SRBs and DRBs). The WTRU may be able to receive downlink (DL) data from the network in a unicast manner, and / or may be able to send uplink (UL) data to the network. The network may control the mobility of the WTRU from one cell / node to another. The network may configure the WTRU to send measurement reports periodically or aperiodically (e.g., if conditions are met (e.g., a neighboring cell becomes better than the serving cell by more than a threshold)). The network may (e.g., based on the report) send a handover (HO) command to the WTRU to move the WTRU to another cell / node. The network may be configured with conditional handover (CHO), where (e.g., instead of sending a measurement report), if the conditions are met, the WTRU may execute a pre-configured HO command. The network may send a HO command to the WTRU without receiving a measurement report (e.g., based on a specific implementation, such as determination of the current location).

[0087] Keeping the WTRU in connected mode may be power intensive for the WTRU (e.g., the WTRU may consume power by continuously monitoring the PDCCH of the serving cell (e.g., for determining the arrival of DL data, for UL data scheduling, etc.). A cell / gNB may accommodate multiple WTRUs in connected mode (e.g., due to resource limitations). The network may put the WTRU into an inactive state (e.g., RRC_INACTIVE) or an idle state (e.g., RRC_IDLE state) if there is no activity in the UL or DL ​​for a certain duration (e.g., based on an inactivity timer operated by the network).

[0088] If the network expects the WTRU to be inactive for a long duration, the network may request that the WTRU be placed in an idle state, such as the RRC_IDLE state. While in the inactive state (e.g., RRC_IDLE), the WTRU may associate with (e.g., camp on) a (e.g., best) cell (e.g., a cell with the best signal level at the highest priority RAT and / or the highest priority frequency within the RAT). The camped cell may facilitate the WTRU to establish a connection via the cell if the WTRU needs to transition back to the connected state.

[0089] As described herein, a cell reselection procedure may be provided and may be used to select a camp-on cell (e.g., a best camp-on cell) for the WTRU. The WTRU may monitor a downlink paging channel to detect DL data arrival. If the WTRU detects a paging from the network indicating DL data arrival and / or if the WTRU needs to send UL data, the WTRU may initiate a connection setup / establishment procedure.

[0090] Figure 2 An example of a radio resource control (RRC) connection establishment, setup and / or connection recovery process starting from an idle state is illustrated, and the idle state may be an RRC_IDLE state. Figure 2 and Figure 3 As shown, the RRC connection establishment process may be a process that includes several round trips to complete and may involve the core network (CN). If the WTRU enters idle mode, the RRC context of the WTRU (e.g., UE) may be released. The WTRU may be unknown at the RAN level. The RAN may have to obtain the WTRU context from the CN. Security may have to be re-established. The WTRU may be reconfigured with DRBs and SRBs before UL / DL data transmission / reception can occur.

[0091] The lengthy setup process may be incompatible with low-latency services. The network (e.g., an NR network) may implement an intermediate state between the connected state and the idle state, which may be referred to as the inactive state. The inactive state may save power. The inactive state may provide the greatest power saving advantage of the idle state (e.g., the WTRU may not continuously monitor the PDCCH, which may be one of the most power-consuming processes in the connected state). The inactive state may allow the RAN to retain the RRC / security context of the WTRU. If the WTRU is to transition or is transitioning to connected mode (e.g., due to the arrival of UL data and / or the reception of a paging indicating the arrival of DL data), the connection may be quickly restored (e.g., without involving the CN, re-establishing the WTRU's security context, and reconfiguring the bearers).

[0092] Figure 3 An example of recovering an RRC connection from an inactive state is illustrated, and the inactive state may be an RRC_INACTIVE state. Figure 4 Examples of different states, such as RRC states, and one or more transitions therebetween are illustrated.

[0093] If the WTRU performs a connection setup / establishment or recovery procedure (e.g., establishing a connection or resuming a connection), then a setup cause and / or a recovery cause (e.g., a connection cause) may be included. The setup or recovery cause may be included in the RRCSetupRequest or RRCResumeRequest. For example, the following causes may be provided to establish a connection and / or resume a connection:

[0094]

[0095] In an example, the connection may be established / resumed due to a voice call or video call originating from the WTRU. The WTRU may set the establishment / resuming cause to mo-VoiceCall (e.g., mobile originated voice call) or mo-VideoCall (e.g., mobile originated video call). In an example, the connection may be established / resumed due to a downlink paging indicating DL data. The WTRU may set the establishment / resuming cause to one of mt-Access (e.g., mobile terminated access), highPriorityAccess, mps-PriorityAccess, or mcs-PriorityAccess (e.g., depending on the access category of the WTRU).

[0096] Mobility can be provided in RRC_IDLE / RRC_INACTIVE (Uu). Figure 5A and Figure 5B As shown, the network (e.g., NR) cell selection / reselection process may be complex. Some examples described herein may focus on the network cell selection / reselection process performed by Figure 5A The highlighted portion of the box in , which covers aspects related to entering RRC_IDLE / RRC_INACTIVE from RRC_CONNECTED (e.g., if an RRC release message is received or a brief cell selection is performed during RRC re-establishment) (e.g., if the WTRU is able to find a suitable cell to camp on).

[0097] Figure 5A and Figure 5B An example of a cell selection and / or reselection process in a network (e.g., an NR network) is illustrated. Cell selection may include a WTRU searching a network (e.g., NR) frequency band. In accordance with CD-SSB, a strong cell (e.g., the strongest cell) may be identified for one or more carrier frequencies (e.g., each carrier frequency). The WTRU may read the cell system information broadcast to identify the PLMN to find a suitable cell to reside in. A suitable cell may be a cell where the measured cell attributes meet the cell selection criteria. The cell PLMN may be a selected PLMN, a registered PLMN, or an equivalent PLMN. The cell may not be barred or reserved. The cell is not part of a tracking area in a list of prohibited tracking areas for roaming.

[0098] In a transition from a connected state (e.g., RRC_CONNECTED) or an inactive state (e.g., RRC_INACTIVE) to an idle state (e.g., RRC_IDLE), the WTRU may camp on a cell. As a result of cell selection, the WTRU may camp on a cell (e.g., according to the frequency assigned by the RRC in the state transition message, if any).

[0099] For example, a cell selection criterion (e.g., referred to as criterion S) may be satisfied if the following conditions are met:

[0100] Srxlev>0 and Squal>0

[0101] in:

[0102] Srxlev=Q rxlevmeas –(Q rxlevmin +Q rxlevminoffset )–P compensation -Qoffset temp

[0103] Squal=Q qualmeas –(Q qualmin +Q qualminoffset )-Qoffset temp

[0104] Table 1 describes an example of parameters for the cell selection criteria:

[0105] Table 1 – Example of parameters for cell selection criteria

[0106]

[0107]

[0108] If cells are evaluated for cell selection as a result of a periodic search for higher priority public land mobile networks (e.g. PLMNs) while camped (e.g. normally) in a visited public land mobile network (VPLMN), the signaled value Q may (e.g. only) be applied rxlevminoffset and Q qualminoffset The WTRU may check the S criteria of a cell using parameter values ​​stored from a different cell of a higher priority PLMN (eg, during a periodic search for a higher priority PLMN).

[0109] Cell reselection may be performed by the WTRU in RRC_IDLE / RRC_INACTIVE. The WTRU may perform intra-frequency, inter-frequency and / or inter-RAT cell reselection.

[0110] The priority of the WTRU may be configured between one or more RATs and / or between frequencies within the same RAT (e.g., fa may have a higher priority, fb may have a medium priority, fc may have a lower priority, etc.) (e.g., whenever an NR cell is available, it may have a higher priority to camp on NR over LTE). A neighbor cell list (NCL) may be provided to the WTRU. The NCL may indicate which neighbor cells (e.g., intra-frequency, inter-frequency, inter-RAT) may be considered for cell reselection. An allowed list may be provided to the WTRU. The allowed list may indicate neighboring cells that may be considered for reselection. An exclusion list may be provided to the WTRU. The exclusion list may indicate neighboring cells that are not suitable for reselection.

[0111] The WTRU may attempt to camp on the cell operating with the highest priority RAT and the highest priority frequency.

[0112] For example, if the serving cell satisfies Srxlev>S IntraSearchP And Squal>S IntraSearchQ , the WTRU may choose not to perform intra-frequency measurements. The WTRU may perform intra-frequency measurements (e.g., in other ways).

[0113] For example, if the serving cell satisfies Srxlev>S nonIntraSearchP And Squal>S nonIntraSearchQ , the WTRU may choose not to perform measurements on NR inter-frequency cells of equal or lower priority or on inter-RAT frequency cells of lower priority. The WTRU may (e.g., in other ways) perform measurements on network (e.g., NR) inter-frequency cells of equal or lower priority and / or on inter-RAT frequency cells of lower priority. Table 2 provides a description of the parameters that may be used in the measurement criteria.

[0114] Table 2 – Examples of parameters in measurement standards

[0115] <![CDATA[S IntraSearchP ]]> Srxlev threshold in dB for intra-frequency measurements. <![CDATA[S IntraSearchQ ]]> Squal threshold (in dB) for intra-frequency measurements. <![CDATA[S nonIntraSearchP ]]> Srxlev threshold (in dB) for NR inter-frequency measurements and inter-RAT measurements. <![CDATA[S nonIntraSearchQ ]]> Squal threshold (in dB) for NR inter-frequency measurements and inter-RAT measurements.

[0116] If the WTRU decides to perform intra-frequency measurements for cell reselection based on this criterion, the WTRU may perform cell ranking of the cells.Inter-frequency and / or inter-RAT reselection may be based on (eg, absolute) priority, where the WTRU attempts to camp on the highest priority frequency available.

[0117] For serving cells (R s ) and for neighboring cells (R n ) can be defined as:

[0118] R s =Q meas,s +Q hyst-Qoffset temp

[0119] R n =Q meas,n -Qoffset-Qoffset temp

[0120] Table 3 provides an example description of the parameters in the cell ranking criteria:

[0121] Table 3 – Examples of parameters in cell ranking criteria

[0122]

[0123] The WTRU may rank (eg, all) cells that satisfy a cell selection criterion S (eg, as described herein).

[0124] By exporting Q meas,n and Q meas,s and using the average RSRP result to calculate the R value, the cells may be ranked according to the R criteria (e.g., as described herein). If rangeToBestCell is not configured, the WTRU may perform cell reselection for the highest ranked cell. If rangeToBestCell is configured, the WTRU may perform cell reselection for a cell with a high number of beams (e.g., the highest number of beams) above a threshold (e.g., absThreshSS-BlocksConsolidation) among cells whose R value may be within the rangeToBestCell of the R value of the highest ranked cell. The WTRU may perform cell reselection for a high ranked cell (e.g., the highest ranked cell) among multiple cells.

[0125] The WTRU may reselect to a cell (e.g., a new cell) if one or more of the following conditions are met: the new cell is preferred over the serving cell according to the cell reselection criteria (e.g., as described herein) during the time interval TreselectionRAT; or a time exceeding a threshold (e.g., 1 second) has passed since the WTRU was stationed in the current serving cell.

[0126] Non-terrestrial networks (NTNs) may facilitate the deployment of wireless networks in areas where land-based antennas cannot be used, for example, due to geography or cost. NTNs coupled with TNs can achieve ubiquitous network coverage (e.g., through 5G networks). NTN deployments can support basic calls and text messages anywhere in the world. NTNs, TNs, and low-orbit satellites can enable enhanced services such as web browsing with NTNs.

[0127] The NTN may include an airborne or space-based platform that may transmit signals from a land-based gNB to a WTRU and vice versa (e.g., via a gateway (GW)). The NTN may support power class 3 WTRUs with omnidirectional antennas and linear polarization, and / or (e.g., very small) aperture antenna (VSAT) terminals with directional antennas and circular polarization. The NTN may support LTE-based narrowband Internet of Things (NB-IoT) and eMTC type devices. The NTN WTRU may support GNSS.

[0128] Aerial or space platforms may be classified according to orbit (e.g., low earth orbit (LEO) satellites with an altitude range of 300km-1500km, geosynchronous orbit (GEO) satellites with an altitude range of 35786km, medium earth orbit (MEO) satellites with an altitude range of 7000km-25000km, and high altitude platform stations (HAPS) with an altitude range of 8km-50km). Satellite platforms may (e.g., further) be classified as having transparent payloads or regenerative payloads. Transparent satellite payloads may implement frequency conversion and RF amplification in the uplink and / or downlink. Multiple transparent satellites may be connected to one land-based gNB. Regenerative satellite payloads may implement a full gNB or gNB DU on a satellite. Regenerative payloads may perform digital processing (e.g., including demodulation, decoding, re-encoding, re-modulation, and / or filtering) on ​​signals.

[0129] One or more of the following radio interfaces may be defined (e.g., configured) at the NTN: a feeder link (e.g., a wireless link between a GW and a satellite); a service link (e.g., a radio link between a satellite and a WTRU); or an inter-satellite link (ISL) (e.g., a transmission link between satellites). An ISL may be supported (e.g., only) by a regenerative payload. An ISL may be a radio or dedicated optical interface.

[0130] Figure 6 An exemplary description of multiple interfaces in a non-terrestrial network is illustrated. Based on the satellite payload configuration, an interface (e.g., a different interface) can be used for (e.g., each) radio link. The NR-Uu radio interface can be used for a service link and / or a feeder link (e.g., for a transparent payload). The NR-Uu interface can be used on a service link (e.g., for a regenerative payload). A satellite radio interface (SRI) can be used for a feeder link (e.g., for a regenerative payload). A UP / CP protocol stack can be provided for a payload configuration (e.g., for each payload configuration).

[0131] NTN satellites may support multiple cells. A cell (e.g., each cell) may include one or more satellite beams. A satellite beam may cover a coverage area on the earth (e.g., like a terrestrial cell). The diameter of a satellite beam in a LEO deployment may range from 100km-1000km, and the diameter in a GEO deployment may range from 200km-3500km. The beam coverage area in a GEO deployment may remain fixed relative to the earth. In a LEO deployment, the area covered by the beam / cell may change over time (e.g., due to satellite movement). If a LEO beam moves continuously on the earth, the beam movement may be classified as earth movement, or if the beam is manipulated to maintain coverage of a fixed position until a cell (e.g., a new cell) exceeds the coverage area (e.g., in discrete and coordinated changes), the beam movement may be classified as earth fixed.

[0132] Due to the altitude of the NTN platform and / or due to the beam diameter, the round trip time (RTT) and / or maximum differential delay of the NTN platform may be (e.g., significantly) greater than that of a terrestrial system. In an example of a transparent NTN deployment, the RTT may range from 25.77 ms (e.g., for LEO at 600 km altitude) to 541.46 ms (e.g., for GEO), with a maximum differential delay from 3.12 ms to 10.3 ms. The RTT of the regenerated payload is approximately half of that of the transparent payload. A transparent configuration may include a service link and a feeder link, while the RTT of the regenerated payload may take into account (e.g., only) the service link. The WTRU may perform timing precompensation (e.g., before initial access) to reduce / minimize the impact on the existing network (e.g., NR) system (e.g., to avoid preamble ambiguity or correct timing reception window).

[0133] The pre-compensation process may include the WTRU obtaining its position (e.g., via GNSS), and / or obtaining a feeder link (e.g., or common) delay and satellite position (e.g., via satellite ephemeris data). Satellite ephemeris data may be broadcast (e.g., periodically) in system information (SI). Satellite ephemeris data may include satellite speed, direction, and / or velocity. The WTRU may estimate the distance (e.g., and therefore delay) to the satellite. The WTRU may add a feeder link delay component to obtain a WTRU-gNB RTT (e.g., full WTRU-gNB RTT), which may be used to offset at least one of a timer, a receive window, or a timing relationship. In some examples, frequency compensation may be performed by the network.

[0134] Examples of WTRU mobility and measurement reporting are provided herein. In an NTN, the RSRP difference between the cell center and the cell edge may not be as significant as in terrestrial systems. In an NTN environment, measurement-based mobility may become less reliable (e.g., based on a much larger cell overlap area). The network may utilize conditional handover and measurement report triggering that depends on location and time. Enhanced mobility may be achieved in LEO deployments, where a fixed WTRU may perform mobility (e.g., approximately every 7 seconds) depending on the deployment characteristics (e.g., due to satellite movement).

[0135] An example of unified access control is provided herein. A WTRU may (e.g., if the WTRU initiates an access attempt) determine one or more access identities (e.g., from a set of standardized access identities) and access categories (e.g., from a set of standardized access categories and an operator-defined access category) that may be associated with the access attempt.

[0136] The set of access identities applicable to the request may be determined by the WTRU. Table 4 shows examples of access identities. For example, the WTRU may (e.g., for each of access identities 1, 2, 3, 11, 12, 13, 14, and 15 shown by way of example in Table 4) check whether the access identity is applicable to the selected PLMN (e.g., if a new PLMN is selected), or otherwise check whether the access identity is applicable to the RPLMN or an equivalent RPLMN; and if no access identity is available, use access identity zero.

[0137] Table 4 – Examples of access identities

[0138]

[0139]

[0140] As shown in Table 4, at Note 1, Access Identity 1 may be valid in the following cases: (i) If the USIM file EF UAC_AIC Indicates that the WTRU is configured for Access Identity 1 and the selected PLMN if another PLMN is selected (e.g., a new PLMN is selected), or the RPLMN is a HPLMN (e.g., if the EHPLMN list does not exist or is empty) or an EHPLMN (e.g., if the EHPLMN list exists), or is a visited PLMN in the home country; (ii) if the WTRU receives a 5GS Network Feature Support IE with the MPS Indicator bit set to "Access Identity 1 Valid" from the RPLMN; or (iii) if the WTRU receives a Priority Indicator IE with the MPS Indicator bit set to "Access Identity 1 Valid" from the RPLMN.

[0141] As shown in Table 4, at Note 2, Access Identity 2 may be valid (e.g., and may be used by a WTRU configured for MCS) in the following cases: If (i) the USIM file EF UAC_AIC Indicates that the WTRU is configured for Access Identity 2 and the selected PLMN, if a new PLMN is selected, or the RPLMN is a HPLMN (e.g., if the EHPLMN list does not exist or is empty) or an EHPLMN (e.g., if the EHPLMN list exists), or is a visited PLMN in the home country; or (ii) the WTRU receives a 5GS Network Feature Support IE with the MCS indicator bit set to "Access Identity 2 Valid" from the RPLMN.

[0142] As shown in Table 4, at Note 3, access identities 11 and 15 may be valid in the HPLMN (e.g., if the EHPLMN list does not exist or is empty) or the EHPLMN (e.g., if the EHPLMN list exists), while access identities 12, 13, and 14 may be valid in the HPLMN and (e.g., only) the visited PLMN of the home country. As shown in Table 4, at Note 4, access identity 3 may be valid if the WTRU is registering or has registered for disaster roaming services.

[0143] For example, as shown in Table 5, the access identity may be mapped to the RRC establishment cause. Table 5 may show an exemplary mapping table for access identity, access category, and establishment cause. Table 5 may show an exemplary mapping table of access identity / access category and RRC establishment cause when establishing an N1 NAS signaling connection via an NR connected to 5GCN.

[0144] Table 5 - Example mapping table of access identity, access category and establishment cause

[0145]

[0146] As shown in Table 5, at Note 1, a WTRU using access category 1 for access barring check may determine a second access category in the range 3 to 7, which may be used to determine the RRC establishment cause. In an example, access identities 0, 1, 2, and 11-15 may be those shown in Table 4.

[0147] Table 6 shows an exemplary mapping table of access categories.

[0148] Table 6 - Example mapping table of access categories

[0149]

[0150]

[0151]

[0152]

[0153] As shown in Table 6, at Note 1, when the service is ongoing, an MM procedure (such as a 5GMM procedure) and a connection management procedure (e.g., a 5GMM connection management procedure) may be provided to establish a PDU session with a request type of "initial emergency request" or "existing emergency PDU session", or to re-establish user plane resources for such a PDU session. This may include a service request procedure initiated using a service request message with the service type IE set to "emergency service fallback".

[0154] As shown in Table 6, at Note 2, an access (e.g., for the purpose of NAS signaling connection resumption during an ongoing service, or for the purpose of NAS signaling connection establishment during an ongoing service following a fallback indication from a lower layer) may be mapped to the access category of the ongoing service (e.g., for the purpose of deriving the RRC establishment cause, but the barring check may be skipped for this access attempt).

[0155] As shown in Table 6, at Note 2a, access (e.g., for the purpose of NAS signaling connection recovery during ongoing MO IMS registration-related signaling, or for the purpose of NAS signaling connection establishment following a fallback indication from a lower layer during ongoing MO IMS registration-related signaling) can be mapped to the access category of the MO IMS registration-related signaling (e.g., for the purpose of deriving the RRC establishment cause, but the barring check can be skipped for this access attempt).

[0156] As shown in Table 6, at Note 3, if the WTRU selects a new SNPN, the selected SNPN may be used to check membership, otherwise, the WTRU may use the RSNPN.

[0157] As shown in Table 6, at Note 4, a connection management process (e.g., a 5GMM connection management process) may be triggered by a NAS transmission process initiated by a WTRU for transmitting MO SMS.

[0158] As shown in Table 6, at Note 5, a WTRU that may be configured for NAS signaling low priority may not be supported. If a WTRU that supports both S1 mode and N1 mode is configured for NAS signaling low priority in S1 mode, the WTRU may ignore the configuration for NAS signaling low priority in N1 mode.

[0159] As shown in Table 6, at Note 6, if the access category applicable to the access attempt is 1, the WTRU may (e.g., additionally) determine a second access category from the range 3 to 7. If more than one access category matches, the access category with the lowest rule number may be selected. The WTRU may use the second access category (e.g., only) to derive the RRC establishment cause for the access attempt.

[0160] As described in Table 6, at Note 7, the EAB override may not apply. For example, if the WTRU may not be configured to allow override of EAB, then the EAB override may not apply (e.g., Override_ExtendedAccessBarring page of the NAS configuration MO). As another example, if the NAS may not have received an indication from upper layers to override EAB, and the WTRU may not have a PDU session established with the EAB override, then the EAB override may not apply.

[0161] As shown in Table 6, at Note 8, the category associated with Access Category 1 may be different from categories a, b, and c associated with EAB.

[0162] As shown in Table 6, at Note 9, one or more of the following may be included: a WTRU-initiated NAS transfer process request for transmitting a mobile-originated location; a connection management process (e.g., a 5GMM connection management process) triggered by a WTRU-initiated NAS transfer process; or a NAS signaling connection recovery during an ongoing 5GC-MO-LR process.

[0163] As shown in Note 10 of Table 6, one or more of the following may be included: a WTRU-initiated NAS transfer procedure for transmitting mobile-initiated signaling transactions to the PCF; a 5GMM connection management procedure triggered by a WTRU-initiated NAS transfer procedure; or NAS signaling connection recovery during an ongoing WTRU-requested policy provisioning procedure for V2XP or both.

[0164] The procedures of unified access control may be used to perform access barring checks on access attempts associated with a given access class and one or more access identities, if requested from upper layers or the RRC layer.

[0165] Figure 7An exemplary scenario is illustrated in which a WTRU may be connected to a multi-layer network (e.g., a terrestrial network (TN) and several layers of NTN). Cell reselection (e.g., as described herein) may enable the WTRU to associate (e.g., camp on) a cell that may have a high priority RAT and / or frequency (e.g., the best cell in the highest priority RAT and frequency), which may allow the WTRU to establish / recover a connection with the cell. This may result in suboptimal operation if the WTRU may be in a coverage area of ​​a multi-layer network (e.g., terrestrial, LEO satellite, MEO satellite, GEO satellite, etc.). A layer (e.g., each layer) may have (e.g., substantially) different characteristics (e.g., latency). For example, when the WTRU is in idle / inactive mode, camping on an NTN cell may result in fewer cell reselections and fewer measurements from the WTRU. If latency requirements are strict (e.g., voice calls, URLLC services, etc.), starting the connection via an NTN cell may be suboptimal. Camping (eg, always) on a TN cell (eg, a small cell at FR2 frequency) may result in faster connection setup / recovery, but may result in a large number of cell reselections and frequent measurements of neighboring cells.

[0166] Based on the strength of the camped / serving cell and the prioritized RAT / frequency and / or based on the suitability of the network / cell for the reason to establish / restore the connection, a (eg, optimal) connection establishment / restore mechanism may be enabled in a multi-layer network.

[0167] The terms RRC_CONNECTED state, connected mode, and connected state may be used interchangeably. The terms RRC_INACTIVE state, inactive mode, and inactive state may be used interchangeably. The terms RRC_IDLE, idle mode, and idle state may be used interchangeably.

[0168] The term "WTRU camped on a cell" may refer to a WTRU in an idle / inactive mode, which may perform paging or monitoring on a cell, and / or (e.g., also) may perform cell reselection measurements and / or cell reselection, which may depend on the current signal level of the cell.

[0169] Terms such as “establishing a connection via a given cell” or “resuming a connection via a given cell” may indicate that the WTRU may perform an initial access procedure (eg, a random access procedure) to the cell.

[0170] The term "network type" may be used to distinguish different types of networks, TN cells / nodes and / or different kinds of NTN cells / nodes.

[0171] Although the examples described herein may focus on the differentiation of behaviors for TN and NTN, these examples (e.g., processes / methods) may (e.g., equally) be applicable to other scenarios, such as where the differentiation is based on other aspects (e.g., operating frequency, available bandwidth, load, etc.). In other scenarios, the WTRU may determine the differentiation aspect (e.g., based on broadcast information from a cell).

[0172] Although the examples focus on WTRU initiated connection establishment / recovery (e.g., arrival of UL data, WTRU initiated voice / video call, etc.), the examples (e.g., procedures / methods) may (e.g., equally) apply to DL cases. The paging indicator may include prioritization information (e.g., for the DL example).

[0173] Connection establishment and / or restoration causes may be mapped to network types. In some examples, the WTRU may be configured with a mapping of connection establishment cause values ​​and preferred layers of the network (e.g., TN, LEO, MEO, GEO, etc.). Table 7 illustrates an exemplary mapping of establishment causes to preferred network types.

[0174] Table 7 - Example mapping of establishment reasons to preferred network types

[0175]

[0176]

[0177] The example in Table 7 shows two types of networks (e.g., TN and NTN for simplicity). In the example, the network can provide mappings for different types of NTNs. For example, mo-Data can be mapped to LEO, while mo-SMS can be mapped to GEO.

[0178] In some examples, the mapping of the establishment cause may be the network layer of the current camped cell. For example, the current camped cell may be used based on the establishment cause, regardless of which layer the current camped cell belongs to.

[0179] Figures 8 to 9An example of cell reselection based on an establishment cause is illustrated. The WTRU may receive configuration information indicating the network layer associated with the corresponding connection cause (e.g., a first network layer associated with a first connection cause and a second network layer associated with a second connection cause). In the example, the WTRU may be configured with a mapping of the connection cause (e.g., a connection recovery cause value) and the preferred layer of the network (e.g., TN, LEO, MEO, GEO, etc.). In the example, the mapping for connection establishment and the mapping for connection recovery may be the same. In the example, the mapping for connection establishment and the mapping for connection recovery may be different. The WTRU may determine the establishment cause (e.g., establishment / recovery cause) (e.g., if the connection is established or recovered). The establishment cause may be a first connection cause or a second connection cause (e.g., the WTRU may determine the establishment cause as a first connection cause or a second connection cause). The WTRU may determine the preferred cell / network layer to connect to based on the mapping (e.g., configuration information), for example, the mapping may indicate that the first network layer is the preferred network type for the first connection cause and the second network layer is the preferred network type for the second connection cause.

[0180] In an example, the WTRU may determine that the establishment cause is a first connection cause. Based on the first connection cause being associated with the first network layer and the first network layer being associated with the first cell, the WTRU may perform connection establishment / recovery via a current cell (e.g., the first cell) associated with (e.g., camped on). For example, the WTRU may camp on an NTN cell and determine that the establishment / recovery cause is the first connection cause. The WTRU may perform establishment / recovery via the NTN cell based on the establishment / recovery cause being the first connection cause (e.g., mo-SMS, which may be mapped to NTN (e.g., in configuration information, e.g., as shown in Table 7)).

[0181] In an example, the WTRU may determine that the establishment cause is a second connection cause. Based on the second connection cause being associated with the second network layer and the second network layer being associated with the second cell, the WTRU may attempt to find a second cell belonging to the second network layer. If the second cell is available (e.g., found) under the preferred network type (e.g., the second network layer), the WTRU may perform cell reselection to the second cell and may establish / restore connection via the second cell. If the second cell is not found at the second network layer, the WTRU may perform connection establishment / restore via its current cell (e.g., the first cell) with which it may be associated (e.g., where it may reside).

[0182] In an example, the WTRU may not perform a comparison of the current camped cell and / or neighbor cells of the preferred layer (e.g., if trying to find a suitable cell in the preferred layer). For example, the WTRU may try to find the best cell in the preferred layer that also meets the S criteria.

[0183] In an example, the WTRU may (e.g., if trying to find a suitable cell in the preferred layer) perform a comparison of the currently camped cell and the neighbor cells of the preferred layer. The WTRU may (e.g., be further configured to) apply an offset on top of the signal level of the neighboring cells of the preferred layer. If the signal strength of the cell of interest plus the offset is better than the serving cell (e.g., exceeds a threshold), the WTRU may reselect to a cell in the preferred layer.

[0184] The access category and / or identity may be mapped to a type of network. In an example, the WTRU may be configured to use the access category as an alternative or in addition to the establishment cause. The access category may be defined (e.g., configured) by the core network (e.g., 5GC) and may be mapped to the establishment cause. The mapping of network types may be performed based on the access category, access identity, a combination thereof, and the like.

[0185] Broadcast uniform access control parameters (eg, barring bits and rules that a WTRU may check before making an access attempt) may correspond to an access class and / or access identity. An operator may define / customize access classes (eg, in the range of 32-62).

[0186] In an example, the WTRU may be configured with one or more RAT selection rules, which may be based on unified access control. For example, the WTRU may determine whether access may be prohibited on a cell (e.g., the current cell) for an access category and / or access identity (e.g., the current access category and access identity). If prohibited, the WTRU may perform a RAT change (e.g., from NTN to TN) to make an access attempt. The cell (e.g., the current cell) may broadcast RAT preferences for one or more access categories and / or access identities. For example, a custom access category 32 may be defined / configured. A RAT preference (e.g., TN or NTN) may be broadcast for the category. The WTRU may use an access category (e.g., 32) to initiate a service. The WTRU may check the RAT preference (e.g., broadcast in system information). The WTRU may attempt to initiate a service based on the broadcast preference.

[0187] In an example, the current cell may broadcast the UAC parameters of the neighbor cell (e.g., UAC parameters applicable to another network). In an example, the access identity and / or access category may be indicated as barred on one cell (e.g., the current cell), but may not be indicated as barred on another cell. The WTRU may attempt to initiate service on another cell where the access identity and / or access category is not barred.

[0188] Examples of prioritized mappings are provided herein. In an example, a WTRU may be configured with a prioritized mapping (e.g., instead of a 1:1 mapping). For example (e.g., for a given setup / recovery reason), the WTRU may be configured with a mapping such as: {GEO, MEO, LEO, TN}. The mapping may indicate that the WTRU may attempt to find a suitable cell at the GEO level (e.g., it may assume that the current camped cell is not GEO), and then (e.g., if no suitable cell is found at the GEO level), the WTRU may attempt to find a suitable cell at the MEO level, and so on.

[0189] An example of multi-layer residency is provided herein. In the example, the WTRU may be configured to perform cell selection / reselection at one or more layers (e.g., at different layers simultaneously). The WTRU may identify cells of a layer. For example, the WTRU may identify cells of each layer (e.g., the best cell of each layer). For example, the WTRU may (e.g., if the WTRU enters an idle or inactive state) perform cell selection on a layer (e.g., each layer) to identify one or more cells of that layer (e.g., the best cell of each layer). The WTRU may perform cell reselection independently at each layer. At any given time, it may be assumed that the WTRU resides in different layers and may be assumed to reside in different layers simultaneously. The WTRU may (e.g., if a connection is to be established / restored) check the mapping of establishment / restore reasons and establish / restore a connection via a resided cell corresponding to a preferred network layer (e.g., the currently resided cell).

[0190] The measurement behavior during idle / inactive mode can be configured to reside on multiple layers.

[0191] For example, cell reselection (eg, conventional cell reselection) may be based on the following: if the serving cell satisfies Srxlev>S nonIntraSearchP And Squal>S nonIntraSearchQ , the WTRU may choose not to perform measurements of equal or lower priority NR inter-frequency cells or lower priority inter-RAT frequency cells. The WTRU may (e.g., in other ways) perform measurements of equal or lower priority inter-frequency cells (e.g., NR inter-frequency cells) and / or lower priority inter-RAT frequency cells.

[0192] The criterion of not enforcing inter-frequency neighbor cells may be applicable (eg, applicable only) to frequencies in the same layer (eg, supporting multi-layer camping).

[0193] In an example, inter-frequency measurements for multi-layer dwell (eg, which might not otherwise be performed if the serving cell is in good radio conditions) may be performed in a relaxed manner (eg, the WTRU reduces the frequency of measurement sampling of neighboring cells, etc.).

[0194] Multi-layer camping may be beneficial in the sense that the WTRU may have identified a cell (e.g., the best cell) at multiple (e.g., all) layers when a connection is to be established / restored. Multi-layer camping may result in a reduction in latency (e.g., compared to the WTRU performing a cell reselection after the WTRU has identified the correct network layer). The WTRU may perform more neighbor cell measurements to perform multi-layer camping, which may (e.g., at least partially) offset the power savings by placing the WTRU in an idle / inactive mode.

[0195] In an example, the WTRU may be configured to use multi-layer camping (e.g., instead of single-layer / one-layer camping) (e.g., for cell reselection based on the WTRU battery level (e.g., current WTRU battery level)). For example, the WTRU may be configured to use multi-layer camping if the WTRU battery level is above a threshold level, and use single-layer camping (e.g., for cell reselection during connection establishment / recovery if the battery level is below a threshold level).

[0196] The WTRU may be provided (e.g., signaled) with a mapping between a connection establishment / resumption cause or access category / identity and a network type. In an example, if the WTRU is placed in an idle or inactive mode, a mapping of network type and establishment / resumption cause may be provided to the WTRU (e.g., in an RRC release message).

[0197] In an example, the mapping may be provided to the WTRU in a message (e.g., RRC reconfiguration, MAC CE, etc.) while the WTRU is in a connected state (e.g., before placing the WTRU in an idle or inactive state using an RRC release). The mapping provided when the WTRU is in connected mode or during a transition to idle / inactive may be referred to as a dedicated mapping.

[0198] In an example, the mapping may be provided to the WTRU via broadcast signaling when the WTRU is in an idle or inactive state (eg, in the SIB of the current cell).

[0199] In an example, a dedicated mapping may be provided to the WTRU before / during a transition to an idle or inactive state (e.g., RRC reconfiguration, RRC release, etc.). When the WTRU is in an idle or inactive state, the WTRU may (e.g., also) determine that there is broadcast information about the mapping. The WTRU may perform one or more of the following operations: the WTRU may use a dedicated mapping configuration received before / during entering the idle / inactive state and ignore the broadcast information; the WTRU may use the broadcast information and ignore / delete the dedicated mapping configuration received before / during transitioning to the idle / inactive state; or the WTRU may use an intersection of information between the dedicated mapping configuration and the broadcast information (e.g., the WTRU may map the same information in the dedicated configuration and the broadcast configuration).

[0200] The WTRU may use a combination of information between a dedicated mapping configuration and the broadcast information.

[0201] In an example, a dedicated mapping may be prioritized. For a setup / recovery cause, the dedicated mapping may be NTN, while for the same setup / recovery cause, the broadcast mapping may be TN. The WTRU may (e.g., first) attempt to find a suitable cell at the NTN level (e.g., assuming the current camped cell is not NTN). The WTRU may (e.g., then) attempt to find a suitable cell at the TN level (e.g., if no suitable cell is found at the NTN level).

[0202] In an example, the broadcast mapping may be prioritized. For a setup / recovery cause, the broadcast mapping may be NTN, while for the same setup / recovery cause, the dedicated mapping may be TN. The WTRU may (e.g., first) attempt to find a suitable cell at the NTN level (e.g., assuming the currently camped cell is not NTN). The WTRU may (e.g., then) attempt to find a suitable cell at the TN level (e.g., if no such suitable cell is found at the NTN level).

[0203] In an example, a WTRU implementation may determine whether to prioritize a dedicated mapping or a broadcast mapping.Signaling may (eg, also) apply to mappings between access categories / identities and network types.

[0204] The WTRU may notify the network of a cell reselection selection during setup / recovery. In an example, the WTRU may be configured to send an indication to the network about a cell reselection performed before (e.g., just after) setup / recovery. For example, the WTRU may include a determined setup cause and information during the setup / recovery process, i.e., due to a setup / recovery cause (e.g., the determined setup cause is a second connection cause associated with a second network layer), the WTRU resides on a first cell associated with a first network layer (e.g., NTN) and is reselected to a second cell associated with a second network layer (e.g., TN). This information may be indicated in one or more of the following ways: in a setup / recovery request message; in a setup / recovery complete message; in an RRC message after setup / recovery is complete (e.g., WTRU assistance information); or in mobility history information (e.g., the mobility history information may be autonomously sent by the WTRU to the network or requested from the network).

[0205] Although the features and elements described above are described in particular combinations, each feature or element may be used alone without the other features and elements of the preferred embodiments, or in various combinations with or without the other features and elements.

[0206] Although the implementation described herein may consider 3GPP specific protocols, it should be understood that the implementation described herein is not limited to such scenarios and is applicable to other wireless systems. For example, although the solution described herein considers LTE, LTE-A, New Radio (NR) or 5G specific protocols, it should be understood that the solution described herein is not limited to such scenarios and is also applicable to other wireless systems.

[0207] The processes described above may be implemented in a computer program, software, and / or firmware incorporated in a computer-readable medium for execution by a computer and / or processor. Examples of computer-readable media include, but are not limited to, electronic signals (sent via wired and / or wireless connections) and / or computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media (such as, but not limited to, built-in hard disks and removable disks), magneto-optical media, and / or optical media (such as compact disk (CD)-ROM disks and / or digital versatile disks (DVDs)). A processor associated with the software may be used to implement a radio frequency transceiver for a WTRU, terminal, base station, RNC, and / or any host computer.

Claims

1. A wireless transmit / receive unit (WTRU), the WTRU comprising: A processor, the processor being configured to: Associating the WTRU with a first cell of a first network layer; Receiving configuration information, wherein the configuration information indicates that the first network layer is associated with a first connection reason and the second network layer is associated with a second connection reason; determining to establish a connection and an associated establishment reason, wherein the associated establishment reason is the second connection reason; performing cell reselection to the second cell based on the first cell being associated with the first network layer, the second connection cause being associated with the second network layer, and a determination that a second cell associated with the second network layer is available; and The connection is established via the second cell.

2. The WTRU of claim 1 , wherein: The establishing of the connection includes establishing the connection or resuming the connection.

3. The WTRU of claim 1 or 2, wherein: The associated establishment cause is related to at least one of: an emergency call; a mobile originated data call; a mobile originated voice call; or a mobile originated SMS.

4. The WTRU of any one of claims 1 to 3, wherein: The first network layer is a non-terrestrial network (NTN), and the second network layer is a terrestrial network (TN).

5. The WTRU of any one of claims 1 to 4, wherein: The processor is further configured to indicate the association establishment cause to a network associated with the second cell.

6. The WTRU of claim 5, wherein: The indication of the association establishment cause is in: a setup or restoration request message; a setup or restoration complete message; or Radio Resource Control (RRC) message.

7. The WTRU of any one of claims 1 to 6, wherein: At a time associated with determining to establish the connection, the WTRU is in an RRC inactive state or an RRC idle state.

8. A method implemented in a wireless transmit / receive unit (WTRU), the method comprising: Associating the WTRU with a first cell of a first network layer; receiving configuration information, wherein the configuration information indicates that the first network layer is associated with a first connection cause and that the second network layer is associated with a second connection cause; Determine to establish a connection and an associated establishment reason, wherein the associated establishment reason is the second connection reason; performing cell reselection to the second cell based on the first cell being associated with the first network layer, the second connection cause being associated with the second network layer, and a determination that a second cell associated with the second network layer is available; and The connection is established via the second cell.

9. The method according to claim 8, wherein: The establishing of the connection includes establishing the connection or resuming the connection.

10. The method according to claim 8 or 9, wherein: The associated establishment cause is related to at least one of: an emergency call; a mobile originated data call; a mobile originated voice call; or a mobile originated SMS.

11. The method according to any one of claims 8 to 10, wherein: The first network layer is a non-terrestrial network (NTN), and the second network layer is a terrestrial network (TN).

12. The method according to any one of claims 8 to 11, wherein: The processor is further configured to indicate the association establishment cause to a network associated with the second cell.

13. The method according to claim 12, wherein: The indication of the association establishment cause is in: a setup or restoration request message; a setup or restoration complete message; or Radio Resource Control (RRC) messages.

14. The method according to any one of claims 8 to 13, wherein: At a time associated with determining to establish the connection, the WTRU is in an RRC inactive state or an RRC idle state.

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