Connectivity supervision and recovery

Abstract

Disclosed are systems, methods, and instrumentalities for connectivity supervision and recovery. The WTRU may supervise its ability to transmit and receive data, including without a control channel (e.g., unlicensed transmission). As an example, the supervision framework may allow the WTRU to supervise feedback channel quality, reciprocity resource quality, and / or transmission attempts. The supervisory processing may depend on a control channel structure or a WTRU state. Supervision processing may be associated with quality of service. The supervisory processing may be WTRU transmission based for energy / resource saving operations. A plurality of recovery processes may be defined. The recovery process may depend on supervisory processing. The recovery process may be optimized for low latency services. The recovery process may involve dedicated recovery resources, light connection transitions, unlicensed resources, and the like. User plane recovery may include reuse of layer 2 context, copying of data to companion MAC instances, and the like. The control plane resume may use RAN paging processing, multiple connections triggered by the WTRU, and the like.

Description

[0001] This application is a divisional application of the Chinese invention patent application filed on August 10, 2017, with application number 201780060936.5 and invention name “Connectivity Supervision and Restoration”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to and the benefit of U.S. Provisional Application No. 62 / 373,071, filed on August 10, 2016, which is incorporated herein by reference. Background Art

[0004] Mobile communications are continuing to develop. The fifth generation may be referred to as 5G. Summary of the invention

[0005] Disclosed are systems, methods, and means for connectivity monitoring and recovery. A WTRU may monitor its ability to transmit and receive data including in the absence of a control channel (e.g., unlicensed transmission). As an example, a monitoring framework may allow a WTRU to monitor feedback channel quality, reciprocal resource quality, and / or transmission attempts. A WTRU may be configured to take one or more of a plurality of recovery actions in accordance with conditions associated with a plurality of monitoring processes.

[0006] The supervision process may depend on the control channel structure (e.g., single or multiple control channels, hierarchical or independent control channels). As an example, the WTRU may monitor the reliability of the control channel (e.g., by using a reference signal associated with the control channel), the quality of the data channel scheduled by the control channel, and / or the quality of the subordinate control channel.

[0007] The supervision process may be associated with the quality of service. The WTRU may monitor one or more supervision processes based on the expected quality of service (eg, in a multi-connectivity or light-connectivity scenario).

[0008] The supervisory processing may depend on the state or conditions of the WTRU, such as one or more of the following: the indemnity or type of control channels monitored by the WTRU, the data transmission capabilities for the WTRU, the type of channels used by the WTRU, the measurement and / or availability of reference signals in a certain state.

[0009] The supervision process may be based on WTRU transmissions for energy / resource efficient operation in dense deployments. The supervision process may be associated with a control function, MAC instance, layer or radio interface.

[0010] Multiple recovery procedures can be defined. The recovery procedure can depend on the supervision process. For example, for low-latency services, one or more recovery procedures can be defined.

[0011] As an example, the recovery process may involve dedicated resources for recovery, light connection transition and / or unlicensed resources. For example, user plane recovery may involve reusing layer 2 context and / or copying data to a companion MAC instance. As an example, control plane recovery may use RAN paging processing and / or multi-connectivity triggered by the WTRU. The recovery process for supervisory processing associated with beam processing may include beam training / beam refinement triggered by the WTRU. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented.

[0013] Figure 1B is a diagram showing that according to one embodiment, Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within a communication system is shown.

[0014] Figure 1C is a diagram showing that according to one embodiment, Figure 1A A system diagram of an example radio access network (RAN) and an example core network (CN) used within a communication system is shown.

[0015] Figure 1D is a diagram showing that according to one embodiment, Figure 1A A system diagram of another exemplary RAN and another exemplary CN used within a communication system is shown.

[0016] Figure 2 is an example of supervised processing.

[0017] Figure 3 is an example of supervised processing.

[0018] Figure 4 is an example of supervised processing. DETAILED DESCRIPTION

[0019] Specific embodiments of illustrative examples will now be described with reference to the various drawings. Although this description provides detailed examples of possible embodiments, it should be noted that these details are intended to be illustrative and not to limit the scope of the present application.

[0020] Figure 1A1 is a diagram showing an exemplary 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 by sharing system resources including wireless bandwidth. For example, the communication system 100 may use 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-sOFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, and filter bank multi-carrier (FBMC), etc.

[0021] like Figure 1A As 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, although it should be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network components. Each WTRU 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. For example, any of the WTRUs 102a, 102b, 102c, 102d may be referred to as a “station” and / or “STA”, which may be configured to transmit and / or receive wireless signals, and may include a user equipment (UE), 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 working in an industrial and / or automated process chain environment), consumer electronic devices, and devices working on a commercial and / or industrial wireless network, etc. The WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as UEs.

[0022] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a and / or the base stations 114b may be any type of device configured to facilitate access to one or more communication networks (e.g., the CN 106 / 115, the Internet 110, and / or other networks 112) by wirelessly interfacing with at least one of the WTRUs 102a, 102b, 102c, 102d. For 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 each of the base stations 114a, 114b is depicted as a single component, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network components.

[0023] The base station 114a may be part of the RAN 104 / 113, and the RAN may also include other base stations and / or network components (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, and the like. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies called cells (not shown). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide wireless service coverage for a specific geographic area that is relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, a cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, that is, each transceiver corresponds to a sector of the cell. In one embodiment, the base station 114a may use multiple-input multiple-output (MIMO) technology and may use multiple transceivers for each sector of the cell. For example, by using beamforming, signals may be transmitted and / or received 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, millimeter 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 described above, the communication system 100 may be a multiple access system and may use one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA, among others. 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 one 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), which may establish the air interface 116 using Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro).

[0027] In one 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 one 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 jointly implement LTE radio access and NR radio access (e.g., using dual connectivity (DC) principles). Thus, the air interface used by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent 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 (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), among others.

[0030] Figure 1A The base station 114b in the figure can be a wireless router, a Home NodeB, a Home eNodeB, or an access point, and can use any appropriate RAT to facilitate wireless connectivity in a local area, such as a business place, a residence, a vehicle, a campus, an industrial facility, an air corridor (such as for use by drones), and a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d can establish a WLAN by implementing a radio technology such as IEEE 802.11. In one embodiment, the base station 114b and the WTRUs 102c, 102d can establish a wireless personal area network (WPAN) by implementing a radio technology such as IEEE 802.15. In another embodiment, the base station 114b and the WTRUs 102c, 102d can establish a picocell or a femtocell by using a cellular-based RAT (such as WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.). Figure 1A As shown, the base station 114b may be directly connected to the Internet 110. Thus, the base station 114b does not need to access the Internet 110 via the 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, fault 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 calls, Internet connectivity, video distribution, etc., and / or may perform advanced security functions such as user authentication. Although in Figure 1AAlthough not shown, 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 or a different RAT as the RAN 104 / 113. For example, in addition to being connected to the RAN 104 / 113 employing NR radio technology, the CN 106 / 115 may also be in communication with other RANs (not shown) employing GSM, UMTS, CDMA 2000, 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 network 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 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, where the one or more RANs may use the same RAT or a different RAT as the RAN 104 / 113.

[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 over 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 showing 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 keyboard 126, a display / touchpad 128, a non-removable memory 130, a removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and other peripherals 138. It should 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), a state machine, and the like. The processor 118 may perform signal coding, 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, however it should be appreciated that the processor 118 and the transceiver 120 may also be integrated into one electronic component or chip.

[0036] The transmit / receive component 122 may be configured to transmit or receive signals to or from a base station (e.g., base station 114a) via the air interface 116. For example, in one embodiment, the transmit / receive component 122 may be an antenna configured to transmit and / or receive RF signals. As an example, in another embodiment, the transmit / receive component 122 may be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals. In yet another embodiment, the transmit / receive component 122 may be configured to transmit and receive RF and light signals. It should be appreciated that the transmit / receive component 122 may be configured to transmit and / or receive any combination of wireless signals.

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

[0038] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive component 122 and to demodulate signals received by the transmit / receive component 122. As described above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers that allow 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 the speaker / microphone 124, the keyboard 126, and / or the display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit), and may receive user input data from these components. The processor 118 may also output user data to the speaker / microphone 124, the keyboard 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store information in any 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, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from and store data in memories that are not physically located in the WTRU 102, such as, for example, 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 for use by 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 (Ni-Cd), nickel-zinc (Ni-Zn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like.

[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) related to 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) via the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It should be appreciated that the WTRU 102 may acquire location information via any suitable positioning method while remaining consistent with an embodiment.

[0042] The processor 118 may be further coupled to other peripherals 138, which may include one or more software 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 videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, Modules, frequency modulation (FM) radio units, digital music players, media players, video game console modules, Internet browsers, virtual reality and / or augmented reality (VR / AR) devices, and activity trackers, etc. Peripheral device 138 may include one or more sensors, which may be one or more of the following: gyroscopes, accelerometers, Hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors, geolocation sensors, altimeters, light sensors, touch sensors, magnetometers, barometers, gesture sensors, biometric sensors, and / or humidity sensors.

[0043] The WTRU 102 may include a full-duplex radio in which the reception or transmission of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous for the radio. The full-duplex radio may include an interface management unit 139 that reduces and / or substantially eliminates self-interference by means of hardware (e.g., chokes) or by signal processing by a processor (e.g., a separate processor (not shown) or by the processor 118). In one embodiment, the WTRU 102 may include a half-duplex radio that transmits or receives some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) or downlink (e.g., for reception)).

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

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

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

[0047] Figure 1C The illustrated CN 106 may include a mobility management gateway (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the foregoing components is described as being part of the CN 106, it should be appreciated that any of these components 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 eNode-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 142 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, performing bearer activation / deactivation processing, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 may also 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 eNode-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 also perform other functions, such as anchoring the user plane during inter-eNode-B handovers, triggering paging processing when DL data is available for the WTRUs 102a, 102b, 102c, and managing and storing the contexts of the WTRUs 102a, 102b, 102c, and the like.

[0050] The SGW 164 may be connected to the PGW 146, 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 communicate with an IP gateway, such as an IP Multimedia Subsystem (IMS) server, and the IP gateway may serve 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 or wireless networks that are owned and / or operated by other service providers.

[0052] Although in Figures 1A-1D Although the WTRU is described as a wireless terminal, it should be appreciated that in certain typical embodiments, such a terminal may use a (eg, temporary or permanent) wired communication interface with a communication network.

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

[0054] A WLAN using an infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may access or be connected to a distributed system (DS) or other types of wired / wireless networks that send traffic into and / or out of the BSS. Traffic originating from outside the BSS and destined for the STA may arrive through the AP and be delivered to the STA. Traffic originating from the STA and destined for a destination outside the BSS may be sent to the AP for delivery to the corresponding destination. Traffic between STAs within the BSS may be sent through the AP, for example, the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. The point-to-point traffic may be sent using a direct link establishment (DLS) between the source and destination STAs (e.g., directly therebetween). In certain typical embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS)). For example, a WLAN using an independent BSS (IBSS) mode does not have an AP, and STAs (eg, all STAs) within or using the IBSS can communicate directly with each other. Here, the IBSS communication mode may sometimes be referred to as an "ad hoc" communication mode.

[0055] When using the 802.11ac infrastructure mode of operation or a similar mode of operation, the AP may transmit a beacon on a fixed channel (e.g., a primary channel). The primary channel may have a fixed width (e.g., a bandwidth of 20 MHz) or a width that is dynamically set with the aid of signaling. The primary channel may be a working channel of the BSS and may be used by STAs to establish a connection with the AP. In certain typical embodiments, carrier sense multiple access (CSMA / CA) with collision avoidance (e.g., in an 802.11 system) may be implemented. For CSMA / CA, STAs (e.g., each STA) including the AP may sense the primary channel. If a particular STA senses / detects and / or determines that the primary channel is busy, the particular STA may back off. In a given BSS, one STA (e.g., only one station) may transmit at any given time.

[0056] A high throughput (HT) STA may communicate using a 40 MHz wide channel (eg, by combining a 20 MHz wide primary channel with a 20 MHz wide adjacent or non-adjacent channel to form a 40 MHz wide channel).

[0057] Very high throughput (VHT) STA can support channels with widths of 20MHz, 40MHz, 80MHz and / or 160MHz. 40MHz 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 discontinuous 80MHz channels (this combination can be referred to as 80+80 configuration). For the 80+80 configuration, after channel coding, the data can be transmitted and passed through a segment parser, which can divide the data into two streams. Inverse fast Fourier transform (IFFT) processing and time domain processing can be performed separately on each stream. The stream can be mapped on two 80MHz channels, and the data can be transmitted by the STA performing the transmission. At the receiver of the STA performing the reception, the above operations for the 80+80 configuration can be opposite, and the combined data can be sent to the medium access control (MAC).

[0058] 802.11af and 802.11ah support sub-1 GHz operating modes. The channel operating bandwidth and carrier used in 802.11af and 802.11ah are reduced compared 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 typical embodiments, 802.11ah may support meter type control / machine type communication (e.g., MTC devices in macro coverage areas). MTC may have certain capabilities, such as limited capabilities including support for (e.g., only support for) certain and / or limited bandwidths. MTC devices may include a battery, and the battery life of the battery is above a threshold (e.g., for maintaining a very long battery life).

[0059] For WLAN systems that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah), these systems include a channel that can be designated as a primary channel. The bandwidth of the primary channel can be equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or limited by a certain STA, where the STA originates from all STAs operating in the BSS that supports the minimum bandwidth operating mode. In the example of 802.11ah, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz and / or other channel bandwidth operating modes, for STAs that support (for example, only support) 1MHz mode (for example, MTC type devices), the width of the primary channel can be 1MHz. Carrier sensing and / or network allocation vector (NAV) settings can depend on the status of the primary channel. If the primary channel is busy (for example, because a STA (which only supports 1MHz operating mode) transmits to the AP), then the entire available frequency band can be considered busy even if most of the frequency band remains space and available for use.

[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. Depending on the country code, the total bandwidth available for 802.11ah is 6MHz to 26MHz.

[0061] Figure 1D 1 is a system diagram showing the RAN 113 and the CN 115 according to one embodiment. As described above, the RAN 113 may communicate with the WTRUs 102a, 102b, 102c using NR radio technology over the air interface 116. The RAN 113 may also communicate 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. Each of the gNBs 180a, 180b, 180c may 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, 180b, 180c may use beamforming processing to transmit signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, for example, the gNB 180a may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a. In one embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation techniques. For example, the gNB 180a may transmit multiple component carriers (not shown) to the WTR 102a. A subset of these component carriers may be on an unlicensed spectrum, while the remaining component carriers may be on a licensed spectrum. In one embodiment, the gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) techniques. For example, the 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 the scalable parameter configurations. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may be different for different transmissions, different cells, and / or different portions of the radio transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of different or scalable lengths (e.g., containing different numbers of OFDM symbols and / or lasting different absolute time lengths).

[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 without accessing other RANs (e.g., 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 anchors. 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 WTRU 102a, 102b, 102c may communicate / connect to the gNB 180a, 180b, 180c while communicating / connecting to another RAN (e.g., the eNode-B 160a, 160b, 160c). For example, the WTRU 102a, 102b, 102c may communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c in a substantially simultaneous manner by implementing the DC principle. In a non-standalone configuration, the eNode-B 160a, 160b, 160c may act as a mobility anchor for the WTRU 102a, 102b, 102c, and the gNB 180a, 180b, 180c may provide additional coverage and / or throughput to serve the WTRU 102a, 102b, 102c.

[0065] Each gNB 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support network slicing, implement dual connectivity, implement interworking between NR and E-UTRA, route user plane data to user plane functions (UPFs) 184a, 184b, and route control plane information to access and mobility management functions (AMFs) 182a, 182b, and the like. Figure 1D As shown, gNBs 180a, 180b, and 180c can communicate with each other through the Xn interface.

[0066] Figure 1DThe CN 115 shown may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and may include a data network (DN) 185a, 185b. Although each of the aforementioned components is described as part of the CN 115, it should be understood that any of these components may be owned and / or operated by entities 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 WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting a specific SMF 183a, 183b, managing registration areas, terminating NAS signaling, and mobility management, etc. The AMF 182a, 1823b may use network slicing processing to customize the CN support provided to the WTRUs 102a, 102b, 102c based on the type of service used by the WTRUs 102a, 102b, 102c. As an 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 massive 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) using 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 may 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 implementation and QoS, and providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0069] The UPF 184a, 184b can be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, and the N3 interface can provide an interface for the WTRU 102a, 102b, 102c to a packet-switched network (e.g., the Internet 110) to facilitate communication between the WTRU 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b can perform other functions, such as routing and forwarding packets, implementing user plane policies, supporting multi-host PDU sessions, processing user plane QoS, buffering downlink packets, and providing mobility anchor processing, 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 acts 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 or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local data network (DN) 185a, 185b via an N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b and through the UPF 184a, 184b.

[0071] In view of Figures 1A-1D and about Figures 1A-1D In accordance with the corresponding description of the present invention, one or more or all of the functions described herein in comparison with one or more of the following may be performed by one or more simulation devices (not shown): WTRU 102a-d, base station 114a-b, eNodeB 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-ab, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or any other device described herein. These simulation devices may be one or more devices configured to simulate one or more or all of the functions herein. For example, these simulation devices may be used to test other devices and / or simulate network and / or WTRU functions.

[0072] The simulation device can be designed to implement one or more tests about other devices in a laboratory environment and / or an operator network environment. For example, the one or more simulation devices can perform one, more or all functions while being implemented and / or deployed as part of a wired and / or wireless communication network in whole or in part to test other devices inside the communication network. The one or more simulation devices can perform one, more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device can be directly coupled to other devices to perform the test, and / or can use over-the-air wireless communication to perform the test.

[0073] One or more simulation devices can perform one or more functions (including all functions) while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test lab and / or a test scenario of a wired and / or wireless communication network that is not deployed (e.g., testing) to implement tests on one or more components. The one or more simulation devices can be test devices. The simulation device can transmit and / or receive data using direct RF coupling and / or wireless communication with the aid of RF circuits (as an example, the circuits can include one or more antennas).

[0074] Air interfaces, such as new radio (NR) access technologies used in 5G systems, can support multiple use cases, such as improved broadband performance (IBB), industrial control and communications (ICC), and vehicular applications (V2X) and massive machine type communications (mMTC). Next generation air interfaces, such as 5G air interfaces, can be configured to allow communications associated with multiple use cases to be implemented within a communication system.

[0075] As an example, the air interface may support ultra-low latency (LLC), ultra-reliable transmission (URC), and MTC operation (including narrowband operation).

[0076] For example, support for ultra-low transmission latency (LLC) may include air interface latency, such as 1 millisecond (or less) round trip time (RTT) and / or transmission time interval (TTI) between 100 and 250 microseconds. Ultra-low access latency may be supported (e.g., time from initial system access to completion of transmission of the first user plane data unit). As an example, end-to-end (e2e) latency supported for ICC and V2X applications may be less than 10 milliseconds.

[0077] As an example, support for Ultra Reliable Communications (URC) may include improved transmission reliability, such as 99.999% transmission success rate and service availability. Mobile speeds in the range of 0-500 km / h may also be supported. As an example, the packet loss rate supported for ICC and V2X applications may be less than 10e -6 .

[0078] As an example, support for MTC operations may include air interface support for narrowband operation (e.g., using less than 200KHz), extended battery life (e.g., up to 15 years of autonomy), and minimal communication overhead for small and infrequent data transmissions (e.g., access latencies of seconds to hours and low data rates in the range of 1-100kbps).

[0079] The 5gFLEX system may be implemented using orthogonal frequency division multiplexing (OFDM), and / or other waveforms for uplink and / or downlink. A 5gFLEX system may be a term used to refer to a wireless communication system designed to implement different use cases using a common or shared radio interface. A 5gFLEX system may correspond to a 5G New Radio (NR) system. The examples described herein are not intended to be limited to specific embodiments thereof, and as such, the examples may be applicable and / or adapted to other waveforms and / or wireless technologies.

[0080] OFDM may be used as a signal format for data transmission (e.g., in LTE and / or IEEE 802.11). OFDM may effectively divide the spectrum into multiple parallel orthogonal subbands. The subcarriers (e.g., each subcarrier) may be shaped using a rectangular window in the time domain, resulting in a sinusoidal-shaped subcarrier in the frequency domain. OFDMA may rely on relatively accurate frequency synchronization and strict management of uplink timing alignment of the cyclic prefix (e.g., to maintain orthogonality between signals and minimize interference between carriers). In some scenarios, strict synchronization requirements may be difficult to achieve (e.g., in systems where the WTRU may be connected to multiple access points simultaneously). Additional power reduction may be applied to uplink transmissions (e.g., to meet spectrum emission requirements of adjacent bands). Segmented spectrum may be aggregated together for use in implementing WTRU transmissions.

[0081] As an example, OFDM (cyclic prefix-based OFDM or CP-OFDM) performance can be improved by imposing stricter RF requirements for implementations (such as operations that use large amounts of contiguous spectrum that are not aggregated). CP-based OFDM transmission systems can provide 5G with a downlink physical layer similar to that of 4G systems by modifying pilot signal density and location.

[0082] 5gFLEX radio access is characterized by a high degree of spectrum flexibility, enabling deployment in different frequency bands with different characteristics, wherein the deployment may include different duplex arrangements, different and / or variable sizes of available spectrum (e.g., contiguous and / or non-contiguous spectrum allocations in the same or different bands with the same or different frequency locations in the band). 5gFLEX radio access may support variable timing aspects, such as supporting multiple TTI lengths as well as asynchronous transmissions.

[0083] Multiple duplex schemes (e.g., time division duplex (TDD), frequency division duplex (FDD), etc.) may be supported. For example, by using spectrum aggregation, supplementary downlink operations (e.g., for FDD) may be supported. FDD operations may support full-duplex FDD and half-duplex FDD operations. As an example, for TDD operations, DL / UL allocations may be dynamic (e.g., not based on a fixed DL / UL frame configuration). DL and / or UL transmission interval lengths may be set per transmission opportunity.

[0084] The WTRU may be configured to receive and / or detect one or more system signatures. The system signature may include a signal structure using a sequence. The signal may be similar to a synchronization signal, such as similar to an NR-SS, such as similar to an LTE PSS and / or SSS. The signature may be specific to (e.g., may uniquely identify) a particular node (or transmission / reception point (TRP)) within a specified area, or may be shared by multiple nodes (or TRPs) within an area that is unknown to and / or related to the WTRU in some way. The WTRU may determine and / or detect a system signature sequence, and may further determine one or more parameters associated with the system. For example, the WTRU may further derive an index therefrom, and may use the index to retrieve associated parameters (e.g., within a table (e.g., an access table)). As an example, the WTRU may use the received power associated with the signature to perform open-loop power control so as to set the initial transmission power when the WTRU determines that it can perform access (and / or transmission) using applicable resources of the system. For example, the WTRU may use the timing of the received signature sequence to, for example, set the transmission timing (e.g., a preamble on a PRACH resource) when the WTRU determines that it can perform access (and / or transmission) using applicable resources of the system.

[0085] A system signature may include any type of signal received by the WTRU for one or more of the purposes described herein.

[0086] The WTRU may be configured with a list of one or more entries. The list may be referred to as an access table. The list may be indexed, for example, where the entries (e.g., each entry) may be associated with a system signature and / or a sequence thereof. The access table may provide initial access parameters for one or more areas. The entries (e.g., each entry) may provide one or more parameters for performing initial system access. These parameters may include one or more of the following: a set of one or more random access parameters in time and / or frequency (including, for example, applicable physical layer resources, such as PRACH resources), an initial power level, and / or a physical layer resource for receiving a response. These parameters may include (e.g., further include) access constraints (e.g., PLMN identity and / or CSG information). These parameters may include (e.g., further include) routing related information, such as one or more applicable routing areas. An entry may be associated with (and / or indexed by) a system signature. Such entries may be shared by multiple nodes (or TRPs). As an example, the WTRU may receive the access table via a transmission using dedicated resources (e.g., configured by RRC) and / or via a transmission using broadcast resources. In the latter case, the transmission period of the access table may be relatively long (eg, up to 10240 milliseconds), which may be longer than the transmission period of the signature (eg, within the range of 100 milliseconds).

[0087] The access table may include any type of system information received by the WTRU for one or more purposes described herein.

[0088] A radio access network (RAN) slice may include (e.g., all) radio access network functions and / or transport network functions and / or resources, such as radio resources and / or backhaul / fronthaul resources and core network functions / resources that may be used or required to provide end-to-end services to users. As an example, network functions may be virtualized on a general-purpose processor, run as network functions on dedicated hardware, or split between dedicated hardware and general-purpose hardware. A PLMN may include one or more network slices. A slice may be similar to an operator's single, public, or common network. A RAN slice may include one or more spectrum operating modes (SOMs) that may be optimized to support the various services that a RAN slice needs to provide.

[0089] In one example, the SOM may correspond to a bandwidth part (BWP). The WTRU may be configured with one or more bandwidth parts (BWP). For example, a BWP may include a group of one or more contiguous physical resource blocks (PRBs). As an example, the configuration of the BWP may include parameter configuration (e.g., including subcarrier spacing, symbol duration), frequency location (e.g., center frequency), and bandwidth (e.g., number of PRBs). The configuration of the downlink BWP may include at least one CORESET. The WTRU may be configured with a default BWP (e.g., for use when performing initial system access or when performing a recovery procedure for a specified cell or carrier).

[0090] A WTRU may be configured with one or more CORESETs. A CORESET may include multiple resource blocks in the frequency domain and multiple symbols (e.g., 1, 2, or 3 symbols) in the time domain. A physical downlink control channel (PDCCH) may be associated with a CORESET. A WTRU may receive downlink control signaling (DCI) on a CORESET.

[0091] In one example, for example, the WTRUs served within a slice may share one or more of the following: (i) service and / or QoE requirements (e.g., ULLRC, eMBB, MMTC); (ii) WTRU categories (e.g., CAT 0 to M and higher, with additional categories defined for frequencies above 6 GHz to differentiate beamforming capabilities); (iii) coverage requirements (e.g., normal coverage, enhanced coverage); (iv) PLMN / operator; (v) support for a specific Uu interface (e.g., LTE, LTE-Evo, 5G below 6 GHz, 5G above 6 GHz, unlicensed); and / or (vi) be served by the same core network slice. The terms "RAN slice" and "slice" are used interchangeably.

[0092] Functions and components used to support the NR system can be logically grouped (e.g., according to the edge control / access plane (AP), the central control plane (CCP), and the central user plane (CUP)). This logical grouping enables the isolation of different components and / or functions in the system. This isolation enables the control, configuration, modification and / or operation of components and / or functions in a separate manner. This separation can be applied to components and functions associated with a specific WTRU, each TRP / NR-eNB, each TRP group (TRPG), each TRPG, each NR-eNB group, each logical channel (LCH) (or its equivalent) or each slice, etc. Further separation between centralized packet processing and access-related packet processing can allow coordination between different functional instances (e.g., system information provision, bearer configuration) or between different instances of different functions (e.g., core network connectivity and user / bearer instances). Edge control functions can be associated with scheduler instances. The WTRU can be configured to associate specific signaling bearers (e.g., transmission paths / methods) used for MAC entity control with the MAC entities involved. The function may (for example, as an alternative) use a transport service of the MAC protocol (for example, as a MAC control component) or a similar service. The central control function (for example, a RAN central control function) may include functions, protocols and / or contexts that are specific to the WTRU and / or applicable to the TRP / edge control function. The central control plane may be considered as an anchor control function that may terminate control interfaces toward the core network (for example, through configuration / setting of routing paths and / or transport paths (for example, based on tuples configured for the WTRU)). The central control function may (for example, additionally) include control functions associated with core network slice selection, CN-RAN interface, QoS management, security (for example, master key management and / or key derivation in accordance with TRP / NR-eNB groups), WTRU capability management, and / or WTRU reachability within the RAN.

[0093] LTE radio link monitoring may include monitoring the downlink (DL) radio link status of the serving cell. The WTRU may monitor the downlink radio quality against thresholds (e.g., Qout and Qin) in one (e.g., every) frame or DRX cycle (e.g., depending on whether DRX is activated). The physical layer may indicate synchronization or desynchronization to a higher layer (e.g., radio resource control (RRC)) (e.g., when the radio link quality is better than Qin or worse than Qout (respectively)). The threshold Qout may be defined as a level at which the downlink radio link cannot be reliably received, and may correspond to a block error rate (e.g., 10%) of an assumed physical downlink control channel (PDCCH) transmission (e.g., taking into account physical control format indicator channel (PCFICH) errors). The threshold Qin may be defined as a level at which the downlink radio link quality can be received more reliably (e.g., significantly improved reliability) than Qout, and may correspond to a block error rate (e.g., 2%) of an assumed PDCCH transmission (e.g., taking into account PCFICH errors). The WTRU may detect that a physical layer problem has occurred (e.g., upon receiving N310 consecutive out-of-sync indications) and may start a recovery timer T310. The WTRU may declare that a radio link failure has occurred (e.g., when the timer expires before receiving N311 consecutive in-sync indications (physical layer problem recovery)). The radio link failure may trigger the WTRU to suspend (e.g., all) radio bearers, reset the MAC, apply default PHY and MAC configurations, and / or perform cell selection. The WTRU may perform RRC connection reestablishment processing (e.g., when a suitable cell is found before the timer expires). The WTRU may abandon the recovery of the connection (e.g., when a suitable cell is not found before the timer expires) in order to enter the IDLE state.

[0094] The next generation air interface (including, as examples, further evolution of LTE Advanced Pro and New Radio (NR)) may use a sufficiently flexible architecture to support multiple use cases with different service requirements (e.g., power-saving services with low overhead and low data rates, such as massive machine type communication (mMTC) services, ultra-reliable low latency communication (URLLC) services, and high data rate enhanced mobile broadband (eMBB) services) for different WTRU capabilities (e.g., low power and low bandwidth WTRUs, WTRUs capable of using very large bandwidths (e.g., 80 MHz), WTRUs supporting high frequencies (e.g., greater than 6 GHz), etc.) in different mobility scenarios to accommodate different deployment scenarios (e.g., centralized, virtualized, distributed on ideal / non-ideal backhaul, etc.).

[0095] The WTRU may remain in a connected state by monitoring various aspects, such as metrics. In order to continue operating in a connected state, the WTRU may need to satisfy criteria associated with the metrics. The WTRU may monitor its ability to be scheduled (e.g., by verifying that the BLER associated with the PDCCH channel may be above a predetermined threshold). As an example, the NR radio link monitoring process may take into account the control channel structure, characteristics of one or more control channel types, transmission aspects of the control channel (e.g., beamforming, possibility of multiple parameter configurations), etc.

[0096] The NR radio link may be designed to attempt to avoid service interruption. For example, the NR radio link may attempt to achieve a mobility interruption time of 0 milliseconds. The mobility interruption time requirement may be for network-controlled mobility (e.g., handover). For example, compared to RLF in LTE systems, in the event of a link failure, it may (e.g., may also) attempt to reduce service interruption.

[0097] In an LTE system WTRU, while in a connected state, the WTRU may have to perform multiple steps to recover from a radio link failure (RLF). As an example, the recovery may include releasing configured resources, switching to idle mode, performing cell selection, initiating contention-based random access, waiting for contention measures, and performing a third layer process (e.g., a reconstruction process). During the radio link recovery process, data transmission to / from the WTRU may have been interrupted. The WTRU may not have yet resumed data transmission (e.g., before completing (e.g., all) recovery steps). This data interruption can have a negative impact on the end user's quality of experience. For services such as URLLC applications, this service interruption due to a radio link failure may result in a service interruption time that the application cannot tolerate.

[0098] In some deployments, conventional control channels may be absent during data transmission (e.g., associated with license-free / unlicensed access). License-free / unlicensed access can reduce the overhead associated with network access and providing a license prior to transmission. As an example, when moving from an inactive state to an active state, access speed can be accelerated by using license-free access (e.g., by eliminating the need to access a channel, request resources, and wait for a license). For the unlicensed access capability, a monitoring process can be provided for it.

[0099] In some deployments, periodic reference signals for monitoring may not be present. Radio link monitoring processing (e.g. in LTE) may rely on the presence of cell-specific reference signals that may be transmitted (e.g. always). The location / arrangement of the reference signals may span (e.g. the entire) system bandwidth. A minimalist carrier approach (e.g. for 5G NR) may restrict transmissions in time, frequency and space. Monitoring processing may be provided for a radio link that may account for the lack of always-on signals.

[0100] The next generation air interface may provide different quality of service. The WTRU may monitor the link quality, whether the active flows / services / bearers are being served as expected (e.g., whether the WTRU may be served by multiple schedulers, such as for multi-connectivity and / or for light connectivity).

[0101] There may be a relationship between the supervision process and the WTRU state. An LTE WTRU may have two states (e.g., IDLE or CONNECTED state). An LTE WTRU may perform radio link monitoring in the CONNECTED state and may move to the IDLE state when a link failure occurs. An NR may have one or more additional states (e.g., RAN controlled state, lightly connected state, connected state with WTRU autonomous mobility, etc.). Supervision processing may be performed in multiple states, and different supervision criteria may apply to different states. Different recovery measures may depend on the supervision criteria and / or state. For example, if a failure occurs while in certain states, a state transition may be performed.

[0102] One or more connectivity supervision processes and recovery processes based on the supervision processes may be used. The supervision process may be used to monitor a supervision signal. The supervision signal may include one or more predefined signals / sequences and / or physical transmission aspects that may provide a reference for the supervision process. The supervision signal may or may not be a dedicated signal transmitted solely for supervision purposes.

[0103] The WTRU may consider one or more signals from the TRP as supervisory signals. As an example, the signal may be a reference signal, such as a cell-specific reference signal, a transmission point-specific reference signal, a BWP-specific reference signal (e.g., NR-SS), a synchronization signal (e.g., primary synchronization signal (PSS) / secondary synchronization signal (SSS)), a low duty cycle signal (e.g., a discovery reference signal (e.g., DRS), and / or a reference signal associated with a location reference (e.g., positioning reference signal (PRS)). A signal may be a combination of multiple signals (e.g., SS blocks), such as a combination of at least one of a PSS, SSS, and a physical broadcast channel (PBCH). A signal may include multiple occurrences of a signal, such as one or more SS blocks corresponding to an SS burst. A signal may be a signature (e.g., a system signature) associated with one or more transmission points. The WTRU may consider a downlink transmission, whose existence and characteristics (e.g., sequence and resource mapping) may be a priori referred to as a supervisory signal.

[0104] One or more control channels of the same or different control channel types may be used in a cell. The type of a control channel may be characterized by one or more aspects alone or in any combination thereof.

[0105] As an example, the control channel type may be characterized by the resources used for control channel transmission, such as the time / frequency resources occupied by the control channel, the subframe type, the control channel duration, the arrangement in the resource grid, the occupied bandwidth, the number and / or nature of clustering of smaller resource groups, and / or the spectrum operation mode, etc.

[0106] As an example, the control channel type may be characterized by the traffic type of the associated data channel, for example, the service type (e.g., eMBB, URLLC, mMTC, etc.), the association of the control channel with a specific slice, etc. As an example, different control channels may be defined for different services.

[0107] As an example, the control channel type may be characterized by information carried in the control channel, such as partial or complete scheduling information or an index of a predefined schedule carried in the control channel, an identity of a WTRU used in the control channel, and the like.

[0108] As an example, the control channel type may be characterized by a reference signal associated with the control channel, such as a cell-specific reference signal, a control channel-specific reference signal or other type of reference signal associated with the control channel, a preamble associated with the control channel, and the like.

[0109] As an example, the control channel type can be characterized by spatial / beamforming characteristics, such as the degree of spatial filtering (e.g., cell-wide, wide beam, narrow beam control channel), the number of antenna ports, the antenna port number, the type of beamforming used (analog, digital, or hybrid), etc.

[0110] As an example, the control channel type may be characterized by the class of WTRUs that receive or monitor the control channel, e.g., WTRUs with limited bandwidth / complexity that may monitor a particular type of control channel.

[0111] As an example, the control channel type may be characterized by a search space associated with the control channel, such as the location of a control channel (eg, an explicit control channel) that may be known a priori or an approximate location at which the WTRU may blindly decode the control channel.

[0112] As an example, the control channel type may be characterized by the WTRU monitoring the control channel, e.g., whether the control channel is visible to all WTRUs in a cell, to a subset of WTRUs in a cell, or dedicated to a specific WTRU, etc.

[0113] As an example, the control channel type can be characterized by the purpose of the control channel, such as scheduling grants (e.g., scheduling a data channel, scheduling another control channel, scheduling discontinuous transmission (DTX) of a TRP, scheduling a reference signal, etc.), DL hybrid automatic repeat request (HARQ) feedback, indicating the type of frame / subframe, triggering signal / preamble transmission from the WTRU, indicating the presence or absence of other channels / signals, or carrying any other DL control information.

[0114] As an example, the control channel type may be characterized by the scheduling periodicity of the control channel (eg, in a periodic manner or on demand).

[0115] As an example, the control channel type may be characterized by the time / frequency relationship of the associated data channels.

[0116] As an example, the control channel type may be characterized by an association with a transmission point or a group of transmission points.

[0117] As an example, the control channel type can be characterized by the applicability and validity of the received information in the control channel, for example, whether the received information is applicable in the same TTI as the received control channel or at a specific offset; whether the received information is valid for one TTI or multiple TTIs, and / or is valid until an explicit modification is made / failure occurs.

[0118] As an example, the control channel type may be characterized by the independence of the control channel, for example, whether the control channel is independent or used in conjunction with another control channel. The control channel may be multiplexed with a data channel.

[0119] As an example, the control channel type may be characterized by any other transmission characteristics of the control channel, such as modulation / coding, transmit power, spreading, waveform, subcarrier spacing, symbol length, CP length / content, scrambling sequence, etc.

[0120] One or more aspects of the control channel may be applicable to the uplink, sidelink, and / or self-backhaul / fronthaul link.

[0121] Beamforming may be characterized by a set of beamforming parameters / configurations for transmission and / or reception of spatial filtering. Beamforming may be characterized by state / context information associated with transmission and / or reception of beamformed transmissions. Beamforming may include or be characterized by one or more of the following: for example, precoding weights, power, timing, associated / configured / assigned / selected reference signal sequences, number of one or more antenna ports, antenna port number, beamforming type (e.g., analog, digital, or hybrid), channel state associated with beamforming, association between transmit and receive beams, a set of triggers / timers / feedback associated with beamforming, identification of one or more transmission points associated with beamforming, beam sounding signal configuration, and the like.

[0122] Beam processing may be used to simplify the signaling of beam characteristics between the WTRU and the eNB. A WTRU may be configured with one or more beam processing. A (eg, each) beam processing may be associated with a beam processing identifier.

[0123] The WTRU may be configured to perform one or more supervision measurements and may detect one or more types of radio failures based on the one or more supervision measurements. A supervision process (SP) may be characterized by a process performed by the WTRU to monitor one or more resources (e.g., reference signals, control channels, etc.) in accordance with a set of configuration parameters and / or rules. A supervision process may include context information and / or a set of monitoring activity states. The WTRU may have zero, one, or more supervision processes instantiated at any point in time. The action of the WTRU may be determined by comparing the state of the supervision process with (pre) defined or configured criteria. For example, when a supervision process fails to meet the criteria, a supervision failure may be declared. Depending on which supervision process fails to meet the criteria pre-defined or configured for it, different types of recovery measures may be performed.

[0124] As an example, the supervision process may be performed at Layer 3 (e.g., RRC) and / or Layer 1 (e.g., PHY) (e.g., based on measurements from Layer 1 and / or based on events observed at Layer 1 and / or Layer 3). A supervision process that relies on transmissions from the network may (e.g., may also) be referred to as a reception-based supervision process.

[0125] A supervisory process may be designed to ensure that the WTRU is able to transmit and / or receive data (e.g., a type of data specific to the supervisory process). For example, the WTRU may perform data transmission on unlicensed resources that do not require a conventional control channel. A supervisory process may be defined to monitor one or more aspects of the WTRU's data transmission and reception (e.g., including data transmission on unlicensed resources) capabilities.

[0126] The WTRU may instantiate a supervisory process for unlicensed resources based on one or more events, either alone or in any combination. For example, when UL data arrives that may be mapped to unlicensed traffic according to a packet forwarding process (e.g., based on the size of the data packet data unit (PDU), the type of data PDU, the type of service), the WTRU may instantiate a supervisory process. If the WTRU does not receive a valid grant and there is a packet latency below the budget, the WTRU may instantiate a supervisory process. The WTRU may instantiate a supervisory process when entering a cell that can support unlicensed access. The WTRU may instantiate a supervisory process when unlicensed resources are configured. The WTRU may instantiate a supervisory process when the access classification broadcast by the cell allows unlicensed access. The WTRU may instantiate a supervisory process when segmentation is not allowed and the received grant is insufficient to transmit the entire PDU. The WTRU may instantiate a supervisory process when the supervisory process for the downlink control channel fails and the WTRU may fall back to using unlicensed resources and instantiate a supervisory process associated with unlicensed access. The WTRU may instantiate a supervisory process when UL synchronization is lost or when the timing alignment timer TAT expires and the characteristics of the unlicensed resources allow non-orthogonal and asynchronous transmissions. The WTRU may instantiate a supervisory process when the maximum number of RACH retransmissions has been reached before a successful response. The WTRU may instantiate a supervisory process when a handover failure has occurred that may trigger a re-establishment. The WTRU may instantiate a supervisory process when the network may be in DTX (e.g., not transmitting control channels).

[0127] The WTRU may monitor aspects associated with unlicensed transmissions. For example, the monitoring process may monitor one or more of the following: (i) feedback channel quality, (ii) reciprocity resource quality, and / or (iii) the number of one or more transmission attempts. The WTRU may monitor one or more aspects individually or in any combination. The WTRU may be configured to declare a monitoring failure when one or more (e.g., all) of the criteria fail. For example, the WTRU may be configured to declare a monitoring failure when the feedback channel quality drops below a threshold, the reciprocity resource quality drops below a threshold, and / or the number of one or more transmission attempts exceeds a threshold.

[0128] The monitored aspects associated with unlicensed transmission may include feedback channel quality. The WTRU may monitor the reception quality of a downlink feedback channel associated with an unlicensed UL transmission. One (e.g., each) downlink feedback channel may be associated with one (e.g., unique) reference signal. The WTRU may determine the downlink feedback channel quality using measurements on the associated reference signal. The reference signal may be cell-specific, WTRU-specific, or may be dedicated to unlicensed transmission feedback. In one example, the reference signal associated with the feedback channel may be a demodulation reference signal. The WTRU may consider (e.g., only consider) measurements performed in a spectrum region and bandwidth associated with a downlink feedback resource that is a subset of the entire system bandwidth. As an example, the WTRU may obtain the DL feedback resource configuration and the associated reference signal configuration in one or more of the following ways: (i) in a cell-specific broadcast, WTRU-specific signaling, or region-specific signaling with the aid of an access table or using a predefined relationship (e.g., relative to UL resources for unlicensed transmission). As an example, when the feedback channel quality is below a predefined threshold for a period of time longer than a predefined duration, the WTRU may declare a supervision failure.

[0129] The monitored aspects associated with unlicensed transmission may include the quality of the reciprocity resources. The WTRU may monitor the reception quality of downlink reference signals within the DL spectrum region. The DL spectrum region may be associated with the UL spectrum region used for unlicensed transmission. The WTRU may assume that the DL and UL resources are reciprocal (e.g., for TDD deployment mode). In one example, the reference signals within the DL spectrum region may be used for other purposes, such as for synchronization, positioning, discovery, etc. As an example, when the quality of the reciprocity resources is below a predefined threshold for a period of time longer than a predefined duration, the WTRU may declare a supervision failure.

[0130] The monitored aspects associated with unlicensed transmissions may include transmission attempts. The WTRU may monitor the number of transmission attempts made on unlicensed resources before feedback (ACK or NACK) is received. As an example, a WTRU UL transmission may fail due to a poor UL channel, due to contention / collision with other WTRU transmissions, or due to a lost feedback message. In one example, the WTRU may monitor the (e.g., average) number of transmission attempts performed in a predefined time window before the transmission is successful. As an example, the WTRU may declare a supervision failure when the number of transmission attempts in a time interval T may be more than a value N and exceeds M times, where N, M and T may be predefined / preconfigured.

[0131] The supervisory process may depend on the control channel structure. The WTRU may associate multiple supervisory processes with a single control channel. The purpose of a supervisory process (e.g., each supervisory process) may be to monitor one or more specific aspects associated with a control channel. The WTRU may monitor a (e.g., single) control channel for a variety of purposes. For example, a WTRU in a lightly connected state may monitor a control channel for RAN paging, and the monitoring may be limited to certain control message types and / or control regions within the control channel. As an example, a WTRU that requires enhanced coverage may need to repeat the same control channel in order to successfully receive a downlink control message. For example, the WTRU may monitor a control channel for a full scheduling grant or a fast scheduling grant, where the scheduling grant may be several bits in length and may activate one or more pre-configured grants. As an example, the supervisory process may monitor the WTRU's capabilities to receive specific control messages according to the use case and / or service type.

[0132] The WTRU may monitor multiple control channels from the network belonging to one or more control channel types. In one example, multiple control channels may be viewed as different regions, different blind decoding configurations, different resource aggregations, and / or different message formats in the same physical control channel. In one (e.g., another) example, the WTRU may monitor two or more control channels with different parameter configurations (e.g., with different symbol lengths, subframe durations, cyclic prefix lengths, subcarrier spacings, etc.). Control channels may be multiplexed in frequency and / or time. A control channel with a specific parameter configuration may be associated with a dedicated reference signal and may be used for a specific service or purpose. The WTRU may monitor two or more control channels. A control channel (e.g., each control channel) may carry a control message / signal that may be associated with a service.

[0133] The WTRU may associate at least one supervisory process with each monitored control channel. Multiple supervisory processes may be activated in the WTRU at a given time. The purpose of a supervisory process (e.g., each supervisory process) may be to ensure that the WTRU can reliably receive the corresponding control channel.

[0134] The interaction between two or more supervisory processes (eg, at a WTRU) may depend on the relationship between the associated control channels.

[0135] The control channel may be independent. Independence may include one or more of the following: (i) the existence of the control channel cannot be determined by another control channel, and / or (ii) the information content in the control channel may be self-sufficient (e.g., may provide complete scheduling grants or other control information).

[0136] The WTRU may associate an independent supervisory process with a monitored independent control channel. In one example, the WTRU may be configured to have an active control channel and a spare control channel. The WTRU may instantiate a supervisory process associated with the spare control channel (e.g., based on the state of the supervisory process associated with the active control channel).

[0137] Control channels may be dependent. Dependencies may include one or more of the following: (i) the presence of one control channel may be determined by the presence of another control channel (e.g., implicitly), (ii) the presence of one control channel may be determined by a control message received in another control channel, and / or (iii) the information content in one control channel may be combined with information from another control channel (e.g., by the WTRU) to obtain a complete control message or scheduling information.

[0138] In one example, the subordinate control channels may be hierarchical, e.g., the WTRU may acquire a control channel lower in the hierarchy by acquiring a control channel higher in the hierarchy. As an example, the WTRU may infer the state of a control channel lower in the hierarchy based on the state of a supervisory process associated with a control channel higher in the hierarchy.

[0139] The supervisory process associated with the control channel may monitor one or more of: (i) reliability of the control channel, (ii) quality of a data channel scheduled by the control channel, and / or (iii) reliability of a dependent control channel.

[0140] A supervisory process may monitor the reliability of a control channel. A supervisory process associated with a control channel may monitor the reliability of a control channel. The WTRU may determine the ability to receive a control channel, for example, based on an expected block error rate of the control channel. It is possible that a reference signal associated with a control channel does not span the entire bandwidth. The WTRU may monitor multiple control channels. One (e.g., each) supervisory process may utilize a measure of a reference signal associated with the corresponding control channel. For example, a reference signal and its associated control channel may be transmitted on the same spectral region or portion of a resource grid multiplexed in time, frequency, and / or code. The WTRU may take into account (e.g., when determining the BLER) the message size / format or control channel type expected to be received in the control channel. For example, when the quality of a reference signal associated with a monitored control channel is likely to be below a predefined threshold for a period of time longer than a predefined duration, the WTRU may declare a supervisory failure.

[0141] The supervisory process may monitor the quality of a data channel scheduled by a control channel. A control channel may be allowed / able to schedule a (e.g., specific) portion of a resource grid (e.g., a spectral region or subset of the entire bandwidth). As an example, the WTRU may monitor the control channel quality and / or the quality of the spectral region associated with a data channel scheduled by the control channel. The WTRU may determine the quality of the data channel, for example, by measuring a reference signal associated with the data channel (e.g., a demodulation reference signal). The WTRU may determine the quality of the data channel, for example, by the number of retransmissions and / or the number of NACKs transmitted. As an example, the WTRU may declare a supervisory failure when the reference signal associated with the data channel is below a predefined threshold or when the number of NACKs is likely to be above a predefined threshold.

[0142] The supervisory process may monitor the reliability of a dependent control channel. The reliability of a first control channel may depend on the reliability of a second control channel. A supervisory process associated with a first control channel may be associated with another supervisory process associated with a second control channel. As an example, the WTRU may trigger supervision of an independent control channel when the dependent control channel reliability is below a threshold.

[0143] As an example, the WTRU may instantiate supervisory processing associated with a control channel based on one or more of the following events: (i) when the WTRU begins reading the control channel (e.g., when the WTRU begins monitoring the control channel); (ii) based on the quality of a subordinate channel (e.g., when supervisory processing of a subordinate control channel fails to meet predetermined criteria); (iii) when the WTRU receives a control channel configuration or when a MAC instance associated with the control channel can be activated; and / or (iv) when a service associated with the control channel can be activated.

[0144] The supervision process may be associated with the quality of service. The WTRU may support different services with different levels of resilience / tolerance to link quality degradation and outages. The WTRU may trigger a recovery action at an appropriate time, e.g., not too early (because the link condition may improve) and not too late (because the link quality may degrade, resulting in a negative impact on the quality of service).

[0145] Flexible configurations may be defined for supervisory processes. In one example, the functionality and parameterization of supervisory processes may depend on the quality of service. For example, a WTRU may be configured for multiple supervisory processes. One (e.g., each) supervisory process may be associated with a type of service. The supervisory process may monitor the expected quality of service provided to the WTRU, which may include, for example, monitoring one or more of: (i) average packet delay, (ii) average number of retransmission attempts, (iii) number of cyclic redundancy check ("CRC") failures on a control channel, (iv) average data rate, and / or (v) link quality.

[0146] The average packet delay may be monitored. The average packet delay may be based on the time a packet is received at the radio interface protocol layer compared to the time a successful acknowledgement of receipt is received from the network. As an example, the WTRU may declare a supervision failure when the average packet delay is likely to be above a predefined threshold.

[0147] The average number of retransmission attempts may be monitored. The average number of retransmission attempts may be based on downlink and uplink transmissions. As an example, the WTRU may declare a supervision failure when the number of retransmission attempts is likely to be higher than a predefined threshold.

[0148] A number of CRC failures on the control channel may be monitored. For example, when the number of CRC failures on the control channel may be above a predetermined threshold, the WTRU may declare a supervision failure.

[0149] The average data rate (eg, the average data rate measured at layer 1 or layer 2) may be monitored. As an example, the WTRU may declare a supervision failure when the average data rate is likely to fall below a predefined threshold.

[0150] Link quality (e.g., taking into account interference from neighboring TRPs (e.g., SINR metrics)) may be monitored. As an example, the WTRU may declare a supervision failure when the SINR is likely to fall below a predefined threshold.

[0151] As an example, the Quality of Service (QoS) aware supervision process may be defined per radio bearer / flow / slice / service or per transport channel. As an example, the QoS supervision process may enable a radio level QoS monitoring process when a single TRP / scheduler does not have centralized knowledge of the cumulative quality of service provided to the WTRU (e.g., in a multi-connectivity scenario). The QoS supervision process may be applied in a lightly connected state, as an example, where the WTRU may move between TRPs / schedulers (e.g., in a transparent manner) and a single TRP / scheduler may not be aware of the WTRU's scheduling history.

[0152] The supervision process associated with QoS may be considered complementary to scheduling assistance (eg, similar to the interaction between the radio link monitoring process and the measurement reporting process).

[0153] Supervisory processing may be associated with sparse reference signals. The supervisory signal may be sparse in time (e.g., not transmitted in all subframes and / or with a fixed periodicity). The supervisory signal may be sparse in frequency (e.g., not spanning the entire system bandwidth). The supervisory signal may be sparse in space (e.g., not broadcast by all TRPs at all times). The supervisory processing may be aware of the sparse nature of the supervisory signal. In one example, the WTRU may adjust the periodicity of the supervisory evaluation, for example, in accordance with the periodicity of the supervisory signal.

[0154] In a multi-connectivity scenario, the WTRU may be connected to multiple TRPs, as an example, where the WTRU may receive sparse supervision signals from one (e.g., each) TRP. In one example, the sparse signal may be a system signature shared by two or more TRPs. Supervision processing may be associated with the system signature (e.g., independent of the transmission point). As an example, the WTRU may declare a supervision failure when the received system signature is likely to be below a predetermined threshold.

[0155] In one example, multiple (e.g., two) types of supervisory signals (e.g., WTRU-specific and cell-specific) may be defined. As an example, when the supervisory process associated with the WTRU-specific signal fails, the WTRU may instantiate a supervisory process to monitor the cell-specific supervisory signal.

[0156] The WTRU may receive sparse supervisory signals from multiple TRPs. The WTRU may combine supervisory signals received from multiple transmission points (e.g., for evaluating the quality of multiple connections). In one (e.g., another) example, the WTRU may perform measurements for multiple TRPs and may evaluate the combined measurement results. The combined results may indicate the quality of the multiple connections.

[0157] A supervisory process may be associated with a beamformed channel. As an example, a beamformed channel may be associated with a beamformed process in order to manage a set of beamforming parameters / configurations for transmission / reception and state / context information associated with the transmission / reception. One or more beamformed processes may be configured for a WTRU and may be associated with a supervisory process. The supervisory process may monitor the suitability of the beam and may be associated with a measurement history (e.g., quality metrics, interference metrics, beam states (active, inactive, prohibited, etc.), transmission / reception activity using the beamformed process, etc.). In one example, (e.g., each) beamformed process that may be configured for a WTRU may be associated with a dedicated supervisory process (e.g., for monitoring the quality of a beamformed link). In one (e.g., another) example, the WTRU may supervise (e.g., only supervise) beamformed processes associated with a service control channel and / or a data channel. In one example, the WTRU may supervise (e.g., only supervise) beamformed processes that may be active and / or whose quality may be above a predetermined threshold. In one (e.g., another) example, the WTRU may be configured (e.g., explicitly) to have a set of beam processes that may be supervised, which may include a set of backup beam processes and a serving beam process. The beam processes may be associated with reference signals specific to the transmit beam. The supervisory process may monitor the reference signals associated with the beam processes.

[0158] As an example, a WTRU may evaluate its connection to a serving TRP based on the status of supervisory processes associated with two or more beam processes. In one example, a set of supervisory processes in a WTRU may distinguish between: (i) loss of a serving data beam associated with a serving TRP, (ii) loss of all data beams associated with a serving TRP, (iii) loss of a serving control beam associated with a serving TRP, and (iv) loss of all control beams associated with a serving TRP.

[0159] As an example, losing a service data beam associated with a service TRP may be based on a reference signal threshold associated with data beam processing. A service data beam may refer to a beam process that is scheduled in an active state.

[0160] As an example, losing all data beams associated with a serving TRP may be based on a reference signal threshold associated with data beam processing.

[0161] As an example, losing a serving control beam associated with a serving TRP may be based on a reference signal threshold associated with a control beam process. A serving control beam may refer to a beam process monitored by a WTRU to receive DL control messages / grants.

[0162] As an example, the loss of all control beams associated with the serving TRP may be based on the reference signal threshold associated with the control beam processing. The WTRU may treat it as a connection failure for the serving TRP.

[0163] The WTRU may monitor and detect the status of each TRP / cell, and / or monitor and detect the status of each multiple TRP / cell (e.g., in a multi-connectivity scenario) by instantiating multiple supervisory processes.

[0164] As an example, the WTRU may instantiate a supervisory process for beam processing based on the state of the supervisory process associated with the linked beam process. As an example, the association may refer to one or more of: (i) a relationship between beam processing associated with a control channel and beam processing associated with a data channel scheduled by the control channel; (ii) a relationship between beam processing associated with the same serving TRP; and / or (iii) a relationship between beam processing associated with the same receive beam on the WTRU.

[0165] The supervision process may depend on the WTRU state. A WTRU may operate in multiple states, such as an idle state, a lightly connected state (RAN controlled state), and a connected state.

[0166] The idle state may be a low activity / low power state in which radio link supervision may not be a priority. In one example, the WTRU may monitor the broadcast channel and the paging channel by instantiating a supervision process.

[0167] The light connection state (RAN control state) may allow (e.g., small) data transfers. The WTRU context may be stored in the RAN and the RAN core connection may be maintained. The WTRU may not have an active connection with the network. As an example, the WTRU may instantiate a supervision process while performing a data transfer.

[0168] The connected state may be an active state with (e.g., large) data transfer. The WTRU may have an active connection with the network. As an example, the WTRU may instantiate a supervision process when entering this state.

[0169] The supervision process may depend on the WTRU state. As an example, the WTRU may instantiate the supervision process based on different characteristics / configurations that may define a certain state. For example, the supervision process may instantiate the supervision process based on one or more of the following characteristics associated with the state: (i) transmission method / resources (e.g., unlicensed, common / shared resources, dedicated resources), (ii) data transmission throughput, (iii) neighbor cell measurements and measurement reports, (iv) DRX cycle and timer, (v) channel type, (vi) mobility (e.g., WTRU self-controlled or network-controlled), (vii) paging area (e.g., cell, RAN paging area, tracking area, etc.), (viii) quality of service, and / or (ix) RLF status.

[0170] The supervision process may be instantiated as needed (e.g., depending on whether data transfer is allowed in this state). In one example, for example, upon entering the connected state, the WTRU may instantiate the supervision process (e.g., for monitoring dedicated resources). The WTRU may instantiate the supervision process as needed or based on configuration, such as in a lightly connected state that may be configured to allow or not allow data transfer.

[0171] The WTRU (eg, when data transfer may be permitted) may be configured to use one or more of the following data transfer methods / resources: (i) unlicensed, (ii) public / shared and / or (iii) dedicated.

[0172] The WTRU may instantiate different supervision processes for (eg, each) data transmission method. As an example, the WTRU may enforce other features that may be specific to each state by instantiating additional supervision processes.

[0173] Supervisory processing is not necessarily required or may not be used, for example, when data transmission may not be permitted.

[0174] The WTRU may transition to the lightly connected state and recover the connection, for example, when the WTRU may be in the connected state and a radio link failure may be detected. Alternatively, for example, the WTRU may transition to idle and initiate a reestablishment procedure. As an example, the WTRU (e.g., in the lightly connected state) may attempt to recover within its current state (e.g., using dedicated resources), attempt to recover using other resources (e.g., public, unlicensed), or (e.g., as an alternative) transition to idle.

[0175] As an example, the WTRU may instantiate a supervisory process based on one or more (e.g., specific) control channels associated with the state. In one example, the WTRU may determine the type of channel to be monitored, for example, based on the data transmission method / resource associated with the state. In one (e.g., another) example, the WTRU may instantiate (e.g., similar) supervisory processes to monitor a paging channel in a lightly connected and connected state. The WTRU (e.g., in a lightly connected state) may operate with a longer DRX and may monitor a paging channel to obtain system information updates (e.g., while monitoring an incoming call). The WTRU (e.g., in a connected state) may monitor a paging channel using different DRXs to obtain (e.g., only obtain) system information updates (e.g., related to ETWS and CMAS).

[0176] In one example, the WTRU (e.g., in an idle state) may instantiate a supervisory process to monitor broadcast channels and paging channels. As an example, when the WTRU detects that the reliability on the broadcast and / or paging channels is low, it may be beneficial (e.g., for URLLC) to monitor the process of broadcast channels and paging channels. The WTRU may initiate a process to transition to a lightly connected or connected state (e.g., to meet latency and reliability requirements). The WTRU may continue to monitor channel conditions. As an example, when one or more broadcast / paging channel conditions return to normal, the WTRU may transition back to an idle state. This operation may provide an active mechanism that enables the WTRU to meet low latency requirements.

[0177] By instantiating the supervision process, appropriate cell measurements for the mobility types supported in a certain (e.g., each) state may be monitored and ensured. For example, the WTRU may perform neighbor cell measurements differently based on the state. As an example, the WTRU (e.g., in a lightly connected state) may perform cell reselection when data transmission is not allowed or is allowed but not performed. The WTRU (e.g., in a connected state) may provide assistance for network-controlled switching by performing measurement reporting. The WTRU (e.g., when data transmission may be allowed in a lightly connected state) may (e.g., may also) support network-controlled switching by performing measurement reporting. In each state, the criteria that may be used to evaluate neighboring cells may be different. For example, in a lightly connected state, the WTRU may use less stringent values ​​than in a connected state. In one example, the WTRU may stay resident / connected to the current cell for a longer period of time instead of reselecting or switching to a higher performance cell. The WTRU may prioritize cells belonging to the same RAN paging area over cells belonging to another RAN paging area or tracking area. The list of neighbor cells to be measured may be based on the state. In one example, the neighbor list in the lightly connected state may be a subset of the neighbor list in the connected state. In one example, the WTRU (e.g., in the lightly connected state) may be disconnected from the RAN PA while data transfer may be ongoing and supervision processing may be running. As an example, the WTRU may perform a RAN paging area update when session continuity can be supported and a network-controlled handover may be triggered (e.g., when session continuity can be supported). As an example, data transfer may be discarded when session continuity is not required. The WTRU may perform a RAN paging area update and may re-initiate a connection in a new RAN paging area. Upon detecting a RAN paging area update, the WTRU may (e.g., as an alternative) transition to the connected state.

[0178] Supervision may be based on one or more WTRU transmissions. Supervision based on reference signal transmissions from a transmission point or cell may be: (i) an increase in overhead (e.g., in ultra-dense deployments where the TRP density may be much higher than the WTRU density) and / or (ii) energy inefficient (e.g., from a network perspective).

[0179] WTRU transmission-based supervision processes may be defined. The WTRU may provide assistance for reception-based supervision processing on the network. Transmission-based supervision processing (e.g., from the WTRU's perspective) may be defined as performing one or more of the following operations: (i) transmitting a "UL supervision signal" and / or (ii) receiving and processing a network response corresponding to a UL supervision signal transmission. As an example, the UL supervision signal may be a reference signal, a preamble, a training sequence, and / or a demodulation reference signal. The UL supervision signal may be either a stand-alone transmission or in addition to a regular data transmission.

[0180] The WTRU may be configured with resources (e.g., by the network) for UL supervisory signal transmission. These resources may include time / frequency resources, WTRU-specific sequences, periodicity, etc. In one example, the UL supervisory signal resources may be periodic and may be configured in broadcast and / or WTRU-specific signaling. In one example, the network may dynamically request UL supervisory signal transmission (e.g., as part of a control message or multiplexed with UL data). In one example, UL resources for supervisory signals may be reserved on multiple TRPs. WTRU transmissions may be received by these TRPs.

[0181] As an example, the WTRU may instantiate transmission-based supervision processing, for example, based on one or more of the following criteria: (i) when reception-based supervision processing meets certain criteria (e.g., when the DL signal quality drops below a threshold), (ii) when the network does not periodically broadcast DL supervision signals, (iii) when explicitly triggered by the network, (iv) based on the WTRU mobility state (e.g., when the WTRU speed or the number of reselection / switching times may be above a threshold) and / or (v) when the WTRU may be configured with "UL supervision signal" resources and / or when these resources may be activated.

[0182] The WTRU may receive a response to the UL supervisory signal, for example, for every N transmissions of the supervisory signal, where N may be greater than or equal to 1. As an example, the network may respond with a predefined DL signal, an acknowledgement in a control channel, and / or an acknowledgement in a RAN paging message with a logical value that may indicate the quality of the WTRU supervisory signal. As an example, the WTRU may declare a supervisory failure when no response is received from the network within a predetermined time interval.

[0183] The supervision process may be associated with a control function, a MAC instance, a layer, or a radio interface. The radio link monitoring process in the WTRU may assume failures in the layer 3 connection for different failure scenarios across multiple (e.g., all) protocol layers, such as L1 failures (e.g., due to desynchronization), MAC failures (e.g., due to random access failures), and RLC failures (e.g., when maximum retransmissions are reached). Layer 3 processes (e.g., cell selection and RRC reestablishment) may (e.g., thereby) recover the link in multiple failure scenarios.

[0184] As examples, the supervision and recovery procedures may be associated with one or more of: (i) a control function, (ii) a MAC instance, and / or (iii) a layer or radio interface.

[0185] Supervision and recovery processes may be associated with a control function. The WTRU may instantiate a supervisory process associated with a control function. In one example, the WTRU (e.g., in a distributed architecture) may have different supervisory processes for one or more edge control functions and a central control function. The WTRU may distinguish between edge control function failures and central control function failures. The supervisory process may store a relationship between a control message (e.g., a configuration) and the source of the control message (e.g., an edge control function). The WTRU may trigger a recovery method associated with a control function (e.g., upon receiving an invalid configuration or security failure). The WTRU may detect and recover from edge control failures without involving a central control function.

[0186] Supervision and recovery processes may be associated with a MAC instance. The WTRU may instantiate a supervision process associated with a MAC instance. For example, a WTRU (e.g., in a multi-connection scenario) may have multiple supervision processes (e.g., one supervision process per MAC instance). As an example, the WTRU may instantiate a supervision process when an associated MAC instance may be activated or when the WTRU begins monitoring a control channel associated with a MAC instance. As an example, the WTRU may obtain the configuration of the supervision process from a dedicated control message associated with the MAC instance, from system information associated with a transmission point, from an anchor MAC instance, or from a (pre-) configuration of an access table. The recovery process may depend on the MAC instance and the type of service associated with the MAC instance. The WTRU may perform autonomous mobility between a set of MAC instances. The WTRU may perform supervision for (e.g., only for) MAC instances for which the WTRU may receive scheduling permissions.

[0187] Supervision and recovery processes may be associated with a layer or a radio interface. The WTRU may instantiate supervision processing associated with a layer or a radio interface. In one example, the WTRU may be connected to an LTE+NR layer (as an example, with close coordination therebetween). The NR and / or LTE layer may be a macro layer or a small cell layer. The WTRU may instantiate multiple (e.g., two) supervision processing, as an example, one of which is associated with the LTE layer and the other is associated with the NR layer. The LTE layer does not understand the configuration for NR supervision, the type of failure to be detected, and / or the process of recovering from NR failures for one or more services specific to the NR layer (e.g., URLLC services). The supervision processing associated with the NR layer may detect and recover failures in the NR layer, which has no interaction or minimal interaction with the LTE layer.

[0188] A (e.g., each) supervisory process may be associated with a recovery method. A recovery method may be configured (e.g., explicitly) to be part of a supervisory process. The WTRU may trigger a recovery method associated with a supervisory process (e.g., upon a supervisory failure). The expected recovery performance (e.g., in terms of outage time and / or overhead) may be configured. The WTRU may select / determine a recovery process that meets the performance requirements. As an example, the WTRU may determine the available recovery processes, e.g., based on the existence / characteristics of configured recovery resources.

[0189] Multiple recovery procedures may be defined. A recovery procedure (e.g., each recovery procedure) may provide different levels of tradeoffs between overhead and service disruption. As an example, the WTRU may select a recovery procedure based on one or more of: (i) the service affected by the disruption (e.g., URLLC or eMBB), (ii) a failure criterion or event (e.g., control channel failure, data transmission failure, or QoS failure), and / or (iii) a failure of a previous recovery method (e.g., switching to a different cell or performing an alternative recovery process upon a dedicated random access failure).

[0190] In one example, a WTRU (e.g., having multiple active services) may (e.g., upon a supervisory failure) trigger a recovery procedure associated with a service that is likely to have the lowest tolerance for interruption. In one (e.g., another) example, a WTRU may be (e.g., explicitly) configured with a recovery procedure to be used upon a supervisory failure.

[0191] The WTRU may ensure that the transmission point or cell selected after recovery may support one or more (eg, all) services or features that were supported or active when the failure occurred.

[0192] The recovery process (e.g., cell selection and reestablishment) may result in (e.g., significant) service interruption time, e.g., for services that cannot tolerate delays (e.g., URLLC). The interruption time may be shortened by optimizing the recovery process (e.g., by avoiding or adding steps).

[0193] In one example regarding resumption optimization, the WTRU may retain a portion of the context and may reuse it upon resumption (as an example, rather than releasing configured resources).

[0194] In an example regarding recovery optimization, the WTRU may remain in connected mode or move to a lightly connected state (as an example, rather than transitioning to idle mode).

[0195] In an example regarding recovery optimization, the WTRU may leverage past measurement results and / or use one or more other processes (described below) to pre-establish links with neighboring TRPs prior to a serving TRP monitoring failure (as an example, rather than performing cell selection).

[0196] In an example regarding recovery optimization, as an example, the WTRU may use an alternative access procedure (eg, unlicensed access) instead of contention-based random access.

[0197] In one example regarding recovery optimization, as an example, the WTRU may use pre-configured resources that may reduce contention (eg, group resources) or avoid contention (eg, dedicated resources) rather than waiting for contention to occur.

[0198] In an example regarding recovery optimization, the WTRU may perform a faster layer 1 or layer 2 based recovery (as an example, rather than performing a layer 3 process, such as a reestablishment process).

[0199] As an example, the WTRU may perform a recovery procedure using predefined / configured radio resources, which may be referred to as "recovery resources". One or more aspects of the recovery resources may be specific to the recovery procedure and / or specific to a particular WTRU or group of WTRUs. Examples of recovery resources may include one or more of the following: (i) a random access preamble or a preamble group, (ii) a recovery resource periodicity (e.g., one or more symbols or subframes), (iii) a recovery resource subband (e.g., a subcarrier group such as a resource block), (iv) unlicensed resources (e.g., orthogonal or non-orthogonal resources, synchronous or asynchronous resources), (v) uplink control channel resources, and / or (vi) uplink signal resources (e.g., supervisory signal resources or sounding reference signal resources).

[0200] A WTRU may be configured to have recovery resources that are applicable in two or more cells / transmission points. For example, a WTRU may be configured to have recovery resources that are valid for a RAN paging area. The WTRU may receive (e.g., in dedicated signaling) a configuration regarding the recovery resources. In one (e.g., alternative) example, the recovery resources may be common to a group of WTRUs. The WTRU may obtain the recovery resource configuration in broadcast signaling. The WTRU may trigger an on-demand system information acquisition procedure to obtain the recovery resource configuration. The WTRU may determine that the recovery resources are valid based on one or more criteria.

[0201] For example, the recovery resource may be determined to be valid based on receiving a valid recovery resource configuration (eg, dedicated or broadcast).

[0202] As an example, the recovery resources may be determined to be valid based on explicit activation from the network (eg, in MAC or L1 signaling). For example, the network may activate the recovery resources based on WTRU feedback and / or measurement reports.

[0203] As an example, the recovery resources may be determined to be valid based on the status of the supervisory process, such as when the supervisory process meets a failure criterion, such as an assumed control channel quality is below a threshold.

[0204] As an example, the recovery resources may be determined to be valid based on the configured services. For example, the WTRU may use the recovery resources for services that expect lower outage times (eg, ultra-low latency services / flows).

[0205] Dedicated WTRU recovery resources may reduce interruption time (possibly at the expense of slightly increased resources, as an example). For example, service interruption at the WTRU may be minimized (i) when the need to perform contention measures may be avoided, (ii) when explicit WTRU identification is not required (e.g., when the process of invoking / using dedicated recovery resources provides implicit identification of the WTRU), and / or (iii) when the recovery process does not require layer 3 signaling exchanges and the additional delays incurred by layer 3 processing may be eliminated.

[0206] Recovery resources may be shared by a subset of WTRUs in a cell, which may provide a better tradeoff between contention / collision and resource utilization.

[0207] The WTRU may (e.g., explicitly) use a second cell or transmission point to request recovery resources for a first cell or transmission point. For example, the WTRU may be connected to two or more transmission points (e.g., in NR). As an example, the WTRU may request recovery resources for a transmission point when an associated supervision process satisfies a failure criterion.

[0208] The WTRU may request recovery resources on the first layer for the second layer. For example, the WTRU may request NR recovery resources on the LTE carrier. As an example, the request may be based on a failure of the supervision process on the NR layer.

[0209] User plane recovery may be provided. Supervisory processing and recovery mechanisms associated with user plane functions may be different from control plane functions. In one example, the user plane functions and control plane functions of the WTRU may terminate in different MAC instances / cells / TRPs. The WTRU may perform user plane recovery separate / independent from control plane recovery.

[0210] The recovery process performed by the WTRU may depend on the QoS / packet forwarding process. The granularity of the recovery process may be at the packet forwarding process or an abstraction thereof (e.g., flow / bearer). The WTRU may not trigger the recovery process for all active services / flows at the same time. For example, some services / flows / packet forwarding processes (e.g., URLLC) may be sensitive to interruptions. As an example, a more conservative supervision process may trigger the recovery process faster than the supervision process for mMTC services.

[0211] The WTRU may retain some portions of the layer 2 context (e.g., portions of the layer 2 configuration and / or layer 2 protocol state) (e.g., in the event of a supervision failure). The WTRU may activate the layer 2 configuration associated with the light connected state. The WTRU may perform data transfer in the light connected state (e.g., when allowed) while performing recovery processing for the fully connected state.

[0212] As an example, the WTRU may (e.g., alternatively or additionally) transition to a sub-state of the connected state when connectionless data transmission can be supported. The WTRU may (e.g., upon supervision failure) stop using resources configured for the connected state. The WTRU may fall back to connectionless transmission for user plane data (e.g., during control plane recovery) and may transition to connection-based transmission (e.g., at the end of control plane recovery).

[0213] The WTRU may be connected to multiple MAC instances / cells / TRPs. The WTRU may be actively scheduled by a subset of MAC instances (e.g., one or more serving / active MAC instances). For example, when the supervisory processing for the user plane function associated with the MAC instance meets the failure criteria (e.g., a failed MAC instance), the WTRU may copy the data transmission to other MAC instances (one or more supporting MAC instances). As an example, the WTRU may select one or more accompanying MAC instances based on signal quality, availability of valid UL timing, status of the supervisory processing, and the like. The WTRU may autonomously perform data replication processing for supporting MAC instances. The WTRU may use a control message (e.g., a buffer status request) to indicate to the supporting MAC instance to start the data replication processing. As an example, the buffer status request may (e.g., as a supplement) indicate the service type / expected quality of service, the identity of the failed MAC instance, and the like. As an example, the WTRU may stop data replication when the radio link of the failed MAC instance improves. Similar mechanisms may also be applied to downlink data transmission. For example, the WTRU may trigger a supporting MAC instance based on a supervisory threshold to transmit a downlink transmission (e.g., in addition to the serving MAC instance). As an example, the WTRU may use a layer 1 or layer 2 or higher layer message to trigger a supporting MAC instance. TRP diversity in downlink transmissions may improve the reliability of data transmission. The WTRU may be configured to have a maximum duration for which data duplication may be allowed (e.g., to avoid excessive resource usage due to data duplication). The WTRU may treat a failed MAC instance as disconnected (e.g., when the maximum duration is exceeded) and may promote a supporting MAC instance to a serving MAC instance (e.g., when not already in service).

[0214] Control plane recovery may be provided. The WTRU may retain / store context (or a portion thereof) associated with one or more serving transmission points (e.g., upon supervision failure). As an example, the context may include received configurations (e.g., radio resource configurations), security contexts, and protocol states (e.g., states / buffers of reordering protocols, ARQ protocols, and / or HARQ protocols). The WTRU may retain a portion of the entire WTRU context. The WTRU may determine the portion of the context to be reset, e.g., based on supervision handling, failure type, and / or service type.

[0215] The recovery process may depend on the WTRU state. For example, once a radio link failure is encountered in the connected state, the WTRU may transition to the lightly connected state. The WTRU may use one or more reconnection processes defined in the lightly connected state as a recovery process / method. For example, the WTRU may monitor RAN paging messages while performing recovery processing in the lightly connected state. The WTRU may receive configuration about dedicated recovery resources in the RAN paging message. When in the connected state, the WTRU may be pre-configured to a lightly connected configuration. When in the lightly connected state, the WTRU may apply / retain a subset of the connected state configuration. As an example, the configuration may be valid, for example, in the entire RAN paging area. In one example, the WTRU may encounter a supervision failure (e.g., based on the reliability of the RAN paging channel) in the lightly connected state. The WTRU may transition from the lightly connected state to the idle state and may perform a tracking area update process or a NAS signaling process (e.g., for synchronizing the WTRU state with the core network state). As an example, when the WTRU and the core network are not synchronized in the lightly connected state, a tracking area update or NAS signaling process may be implemented at this time. As an example, from the RAN perspective, the WTRU may be in a lightly connected state, while from the core network perspective, the WTRU may be in a connected state.

[0216] The WTRU may autonomously establish a link to a neighboring TRP prior to a supervisory failure (e.g., when the serving TRP may be close to a supervisory failure or operating under suboptimal radio conditions). The WTRU may read broadcast information from a neighboring TRP in order to perform initial access. The WTRU may (e.g., as an alternative) request (e.g., from a serving TRP) system information from a neighboring cell. As an example, the serving TRP may (e.g., as an alternative) provide system information to a neighboring TRP (e.g., based on measurement reports originating from the WTRU). As an example, based on trigger processing (e.g., through early RLF detection), WTRU-triggered autonomous multiple connections or make-before-break connections for different TRPs may be performed.

[0217] The WTRU may receive and store radio resource configurations that may be associated with one or more neighboring cells. The radio resource configuration may be specific to the WTRU and / or to an active service in the WTRU. The radio resource configuration may be specific to supervisory processing. The WTRU may receive and may store a configuration of an activation signal associated with (e.g., each) neighboring cell radio resource configuration. In one example, the activation signal may include UL resources for signal / preamble control transmission originating from the WTRU. The WTRU may select a neighboring cell (e.g., in the event of a supervisory processing failure) and may trigger a UL activation signal associated with the neighboring cell. The network may confirm receipt of the activation signal. The WTRU may apply (e.g., upon confirmation) the stored configuration associated with the neighboring cell. As an example, activation based on pre-configuration and fast UL signals may eliminate delays caused by random access and layer signaling, and may (e.g., significantly) shorten the recovery time.

[0218] The WTRU may indicate (e.g., to the network) the cause of the failure (e.g., upon successful recovery). The indication may include a supervisory process identity. There may be multiple parallel supervisory processes active on the WTRU. Each of the multiple processes may correspond to a different QoS. As an example, the WTRU may report the status of a supervisory process associated with a URLLC service by including the cause of the failure with a supervisory process ID, while other services (e.g., eMBB) may still be active.

[0219] The WTRU may experience a failure in the supervision process associated with a low latency control channel. The WTRU may switch (e.g., as a recovery procedure) to a regular control channel, a control channel with a longer TTI / periodicity, a control channel with better protection (e.g., coding), a control channel with enhanced coverage (e.g., through repetition), or a control channel on a low frequency carrier.

[0220] The recovery process may be specific to the supervisory process associated with the beamforming process. The WTRU may use other active beamforming processes (e.g., upon supervisory process failure) to indicate the cause of the failure to the network and may trigger a recovery process. For example, upon supervisory failure, the WTRU may trigger a beam refinement or beam training process as a recovery process.

[0221] Figure 2-4 Examples of supervised processing are provided. Figure 2-4 The nodes or TRPs that communicate with the WTRU are shown. Each TRP has beams y and z. Figure 3 shows the radio link failures that have been identified, and Figure 4 An exemplary recovery process is shown.

[0222] Figure 2-4Any of the supervisory processes described herein may be used. For example, the WTRU may monitor RSx associated with a TTI duration x. A failure criterion or event may be defined as whether RSx is less than a threshold x in time Tx. The WTRU monitors RSx and determines whether a failure event threshold is met. If the WTRU determines that the failure criterion is met, the WTRU determines and performs recovery measures. In this example, the recovery measure may be to fall back to TTI duration y.

[0223] In another example, the WTRU may monitor RSy associated with beam y. A failure criterion or event may be defined as whether RSy is less than a threshold y for a period of time Ty. The WTRU monitors RSy and determines whether a failure event threshold is met. If the WTRU determines that the failure criterion is met, then the WTRU determines and performs recovery measures. In this example, Figure 4 As shown, the recovery measure may include triggering a beam training process on the recovery resource z.

[0224] In another example, the WTRU may monitor RSz associated with beam z. A failure criterion or event may be defined as whether RSz is less than a threshold z for a period of time Tz. The WTRU monitors RSz and determines whether a failure event threshold is met. If the WTRU determines that the failure criterion is met, the WTRU determines and performs recovery measures. In this example, the recovery measures may include triggering a beam training process on a recovery resource y.

[0225] In another example, the WTRU may monitor the average data packet delay of the URLLC. A fault criterion or event may be defined as whether the average data packet delay is less than a threshold time. The WTRU monitors the average data packet delay and determines whether a fault event threshold is met. If the WTRU determines that the fault criterion is met, the WTRU determines and executes recovery measures. In this example, the recovery measures may include triggering different transmission methods.

[0226] Disclosed are systems, methods and means for connectivity monitoring and recovery. A WTRU may monitor its ability to transmit and receive data, including in the absence of a control channel (e.g., unlicensed transmission). As an example, a monitoring framework may allow a WTRU to monitor feedback channel quality, reciprocity resource quality and / or transmission attempts. The monitoring process may depend on the control channel structure or the WTRU state. The monitoring process may be associated with the quality of service. For energy / resource saving operation, the monitoring process may be based on WTRU transmissions. Multiple recovery processes may be defined. The recovery process may depend on the monitoring process. The recovery process may be optimized for low-latency services. The recovery process may involve dedicated recovery resources, light connection transitions, unlicensed resources, and the like. User plane recovery may include reusing layer 2 contexts, copying data to a companion MAC instance, and the like. Control plane recovery may use RAN paging processing, multi-connectivity triggered by the WTRU, and the like. Recovery processing for monitoring processing associated with beam processing may include beam training processing / beam refinement processing triggered by the WTRU, and the like.

[0227] The processes and approaches described herein may be applied in any combination and may be applied to other wireless technologies as well as other services.

[0228] WTRU may refer to a physical device identity, or a user identity (eg, a subscription-related identity), such as an MSISDN, SIP URI, etc. WTRU may refer to an application-based identity, such as a user name that may be used per application.

[0229] Each computing system described herein may have one or more computer processors having memory configured with executable instructions, or hardware for performing the functions described herein, including determining the parameters described herein and sending and receiving messages between entities (e.g., WTRU and network). The above processes may be implemented in a computer program, software, and / or firmware that is incorporated into a computer-readable medium for execution by a computer and / or processor.

[0230] The above processing can be implemented in a computer program, software and / or firmware that introduces a computer-readable medium for execution by a computer and / or a processor. Examples of computer-readable media include, but are not limited to, electrical signals (transmitted 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, buffer memory, semiconductor storage devices, magnetic media (such as, but not limited to, internal hard disks and removable disks), magneto-optical media and / or optical media (such as CDs and / or digital versatile discs (DVDs)). A processor associated with the software can be used to implement a radio frequency transceiver used in a WTRU, a terminal, a base station, an RNC, or any computer host.

Claims

1. A wireless transmit / receive unit (WTRU), comprising: A processor configured to: establishing at least a first supervisory process and a second supervisory process, each of the first supervisory process and the second supervisory process being associated with one or more radio link failure (RLF) criteria for a single transmit-receive point and a type of transmission or communication link between the single transmit-receive point and the WTRU, wherein each of the established supervisory processes is further associated with at least one of: a bandwidth part (BWP), a beam process, a control channel, and a quality of service (QoS); determining that a first RLF criterion associated with a first one of the established supervisory processes has been satisfied; and In response to determining that the first RLF criterion has been met, a recovery measure associated with the first supervisory process is performed based on an identity of the first supervisory process and a status of at least the second supervisory process.

2. The WTRU of claim 1 , wherein: Each of the established supervisory processes includes a predefined reference signal.

3. The WTRU of claim 1 , wherein: The type of transmission or communication link is associated with a control channel or an unlicensed resource.

4. The WTRU of claim 1 , wherein: Each of the established supervisory processes comprises monitoring at least one signal characteristic or at least one beam characteristic of a transmission / communication link of said type.

5. The WTRU of claim 4, wherein: The at least one signal characteristic includes at least one of: average packet delay, signal quality, average number of transmission attempts, one or more cyclic redundancy check (CRC) failures, average data rate, and link quality taking interference into account.

6. The WTRU of claim 4, wherein: The at least one beam characteristic includes at least one of: a quality metric, an interference metric, a beam state, a transmission activity associated with the beam, and a reception activity associated with the beam.

7. The WTRU of claim 1 , wherein: Each of the established supervisory processes includes monitoring a reception quality of a downlink feedback channel associated with unlicensed resources or one or more transmission attempts.

8. The WTRU of claim 1 , wherein: The recovery measure comprises at least one of the following: triggering beam training, triggering use of another beam resource, triggering a different transmission type, triggering a different transmission time interval, and changing the transmission time interval.

9. The WTRU of claim 1 , wherein: Each of the established supervisory processes includes adjusting a monitoring period of a reference signal based on a period of the reference signal.

10. The WTRU of claim 1 wherein: The first RLF criterion includes at least one of the following: the WTRU enters a lightly connected state and activates a MAC channel.

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