EP4666798A1 - Methods implemented in a wtru for blind retransmission in non-terrestrial networks - Google Patents

Abstract

Methods implemented in a wireless transmit receive unit (WTRU) are described for determining additional PDCCH monitoring occasions to check for grants for blind Msg3 re-transmission based on receiving explicit indication to perform a second PDCCH monitoring, an Msg3 characteristic, an override condition or satisfaction of one or more conditions.

Description

METHODS IMPLEMENTED IN A WTRU FOR BLIND RETRANSMISSION IN NON-TERRESTRIAL NETWORKS

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 63/445,609 filed February 14, 2023, the contents of which are incorporated herein by reference.

BACKGROUND

[0002] In terrestrial networks the gap between a MAC entity stopping the ra-ResponseWindow and starting the ra-Contention esolutionTimer is usually sufficiently short to allow near-continuous monitoring of PDCCH. Offsetting the start of the ra-ContentionResolutionTimer in non-terrestrial networks (NTN), significantly increases this gap, limiting the ability to quickly receive a blind Msg3 retransmission grant after the ra- ResponseWindow is stopped.

[0003] The additional delay means that the network may not schedule a blind MSG3 retransmission until at least the WTRU-gNB round-trip-time (RTT), limiting scheduler flexibility and increasing latency of the RA procedure. Furthermore, MSG3 repetition may not always be a suitable solution in NTN considering the RACH congestion caused by large number of WTRUs simultaneously performing RACH, which can place limitations on the resources needed to perform multiple consecutive repetitions. The WTRU may always continue monitoring PDCCH between RA windows, however a blind retransmission grant is opportunistic, and the network may always choose not to provide one. Considering the WTRU-gNB RTT can be quite long, this can result in additional and unnecessary WTRU power consumption.

[0004] Thus, it may be desirable to enable blind retransmission grant reception in less than WTRU-gNB RTT after initial MSG3 retransmission in non-terrestrial networks, without the need for the WTRU to monitor PDCCH continuously.

SUMMARY

[0005] In embodiments, a method may be implemented in a wireless transmit receive unit (WTRU) for determining additional monitoring occasions for a physical downlink control channel (PDCCH) transmission. The method may include: receiving first configuration information for performing a first monitoring for a first PDCCH transmission for a first Msg3 re-transmission; receiving second configuration information for performing a second monitoring for a second PDCCH transmission for a second Msg3 re-transmission; transmitting a physical random access channel (PRACH) preamble; starting a monitoring window and monitoring for a PDCCH transmission for a Random Access Response; receiving a Random Access Response and stopping the monitoring window; transmitting at least one Msg3 based on the received Random Access Response; monitoring for a PDCCH transmission based on the second monitoring for a PDCCH transmission for the second Msg3 re-transmission; receiving a PDCCH transmission based on the second monitoring for the second PDCCH transmission; and re-transmitting a third Msg3 based on a grant received in the PDCCH transmission. In further embodiments, the method may include wherein the second configuration information includes an explicit indication to perform the second monitoring for the PDCCH transmission for the second Msg3 retransmission. In further embodiments, the method may include wherein the explicit indication is received via a Random Access Response; a PDCCH order, or SIB signaling. In further embodiments, the method may include wherein a validity time is associated with the explicit indication indicating a time period for which the explicit indication is valid. In further embodiments, the method may include wherein a validity area is associated with the explicit indication indicating an area in which the explicit indication is valid. In further embodiments, the method may include wherein the explicit indication includes time period information for when grants for Msg3 re-transmission are expected to be received. In further embodiments, the method may include monitoring for a PDCCH transmission based on the first monitoring for the first PDCCH transmission after the second monitoring for the second PDCCH transmission, and transmitting a fourth Msg3 when a second PDCCH transmission is received. In further embodiments the conditions to perform the second monitoring for PDCCH transmission for blind Msg3 re-transmission, are based on one or more values. In further embodiments, the values may include at least one of a WTRU distance from a cell center, angle of a satellite relative to earth, or RSRP. In further embodiments, the method may include the values are provided in system information, a handover command, RRC release message, or RAR.

[0006] In further embodiments, a method may be implemented in WTRU for determining additional occasions for monitoring for a PDCCH transmission occasions, the method may include: receiving first configuration information for performing a first monitoring for a first PDCCH transmission for a first Msg3 retransmission; receiving second configuration information for performing a second monitoring for a second PDCCH transmission for a second Msg3 re-transmission; starting a response window and monitoring for a PDCCH transmission for an RAR; receiving an RAR and stopping the response window; transmitting at least one Msg3 based on the received RAR; determining based on an Msg3 repetition characteristic or an override condition whether to perform the second monitoring for a second PDCCH transmission for re-transmission; and monitoring for second PDCCH transmission for the second Msg3 re-transmission grant in response to the Msg3 repetition characteristic being met or the override condition not being satisfied. In further embodiments, the method may include wherein, a third configuration information is provided via radio resource control (RRC) signaling, a random access message, medium access control control element (MAC CE), paging message or downlink control information (DCI), the third configuration information indicating whether the WTRU performs the additional monitoring for blind Msg3 transmission grant based on Msg3 characteristics. In further embodiments, a method may include wherein the override condition is received via random access response (RAR), message B (MSGB) or system information. In further embodiments, the method may include wherein the second monitoring for PDCCH transmission is not performed regardless of Msg3 characteristics if the override condition is met. In further embodiments, the method may include wherein whether the WTRU performs the second monitoring or additional monitoring is a function of a predetermined number of Msg3 retransmissions.

[0007] In further embodiments, a WTRU may be configured to perform any of the above-stated methods.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, wherein like reference numerals in the figures indicate like elements, and wherein:

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

[0010] FIG. 1 B is a system diagram illustrating an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in FIG 1A according to an embodiment;

[0011] FIG. 1C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG. 1A according to an embodiment;

[0012] FIG. 1D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG 1A according to an embodiment;

[0013] FIG. 2 is a messaging diagram for a four-step contention-based random access procedure;

[0014] FIG. 3 is a messaging diagram for a two-step contention-based random access procedure;

[0015] FIG. 4 is a timing diagram of an Msg3 blind retransmission grant reception in a terrestrial network;

[0016] FIG. 5 is a timing diagram of an Msg3 blind retransmission grant reception in a non-terrestrial network;

[0017] FIG. 6 is an exemplary flow diagram for additional PDCCH monitoring;

[0018] FIG. 7 is an exemplary flow diagram for triggering additional PDCCH monitoring based on explicit indication;

[0019] FIG. 8 is an exemplary flow diagram for triggering additional PDCCH monitoring based on Msg3 repetition characteristics;

[0020] FIG. 9 is an exemplary flow diagram for triggering additional PDCCH monitoring based on satisfaction of conditions;

[0021] FIG. 10A is an exemplary flow diagram for triggering additional PDCCH monitoring;

[0022] FIG. 10B is a further exemplary flow diagram for triggering additional PDCCH monitoring;

[0023] FIG. 11 is a timing diagram for additional monitoring occasions; [0024] FIG. 12 is a timing diagram for additional monitoring occasions; and

[0025] FIG. 13 is a timing diagram for additional monitoring occasions.

DETAILED DESCRIPTION

[0026] FIG. 1A is a diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), singlecarrier FDMA (SC-FDMA), zero-tail unique-word discrete Fourier transform Spread OFDM (ZT-UW-DFT-S- OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0027] As shown in FIG. 1A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (ON) 106, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though itwill be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a station (STA), 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 telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a UE.

[0028] The communications systems 100 may also include a base station 114a and/or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106, the Internet 110, and/or the other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a NodeB, an eNode B (eNB), a Home Node B, a Home eNode B, a next generation NodeB, such as a gNode B (gNB), a new radio (NR) NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements.

[0029] The base station 114a may be part of the RAN 104, which may also include other base stations and/or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, 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, which may be referred to as a cell (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum A cell may provide coverage for a wireless service to a specific geographical area that may be relatively fixed or that may change over time. The cell may further be divided into cell sectors. For example, the 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, i.e., one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and/or receive signals in desired spatial directions.

[0030] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0031] More specifically, as noted above, the communications system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station 114a in the RAN 104 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 116 using wideband CDMA (WCDMA). 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 Uplink (UL) Packet Access (HSUPA).

[0032] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/or LTE-Advanced Pro (LTE-A Pro).

[0033] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR Radio Access , which may establish the air interface 116 using NR.

[0034] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for instance using dual connectivity (DC) principles. Thus, the air interface utilized by 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 , an eNB and a gNB).

[0035] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like. [0036] The base station 114b in FIG 1A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106.

[0037] The RAN 104 may be in communication with the CN 106, 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 varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high-level security functions, such as user authentication. Although not shown in FIG. 1A, it will be appreciated that the RAN 104 and/or the CN 106 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104, which may be utilizing a NR radio technology, the CN 106 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0038] The CN 106 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and/or the other networks 112. The PSTN 108 may include circuit-switched telephone networks that provide plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and/or the internet protocol (IP) in the TCP/IP internet protocol suite. The networks 112 may include wired and/or wireless communications networks owned and/or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 or a different RAT.

[0039] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications 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). For example, the WTRU 102c shown in FIG. 1 A may be configured to communicate with the base station 114a, which may employ a cellularbased radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0040] FIG. 1 B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1B, the WTRU 102 may include a processor 118, a transceiver 120, a transmit/receive element 122, a speaker/microphone 124, a keypad 126, a display/touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and/or other peripherals 138, among others. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0041] 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 in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), 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. While FIG. 1 B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0042] The transmit/receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, the transmit/receive element 122 may be an antenna configured to transmit and/or receive RF signals. In an embodiment, the transmit/receive element 122 may be an emitter/detector configured to transmit and/or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit/receive element 122 may be configured to transmit and/or receive both RF and light signals. It will be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals.

[0043] Although the transmit/receive element 122 is depicted in FIG. 1 B as a single element, the WTRU 102 may include any number of transmit/receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit/receive elements 122 (e g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116. [0044] The transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit/receive element 122 and to demodulate the signals that are received by the transmit/receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11 , for example.

[0045] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit) The processor 118 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128. In addition, the processor 118 may access information from, and store data in, any type of suitable memory, such as the non-removable memory 130 and/or the removable memory 132. The non-removable memory 130 may include random-access memory (RAM), 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, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0046] The processor 118 may receive power from the power source 134, and may be configured to distribute and/or control the power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li- ion), etc.), solar cells, fuel cells, and the like.

[0047] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or in lieu of, the information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from a base station (e.g., base stations 114a, 114b) and/or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment

[0048] The processor 118 may further be 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 e-compass, a satellite transceiver, a digital camera (for photographs and/or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a handsfree headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a Virtual Reality and/or Augmented Reality (VR/AR) device, an activity tracker, and the like. The peripherals 138 may include one or more sensors. The sensors may be one or more of a gyroscope, an accelerometer, a hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, a humidity sensor and the like.

[0049] The WTRU 102 may include a full duplex radio for which transmission and reception of some or all of the signals (e g., associated with particular subframes for both the UL (e.g. , for transmission) and DL (e.g., for reception) may be concurrent and/or simultaneous. The full duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e g., for transmission) or the DL (e g., for reception)).

[0050] FIG. 1C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0051] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a.

[0052] Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and/or DL, and the like. As shown in FIG. 1 C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0053] The CN 106 shown in FIG. 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. While the foregoing elements are depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator.

[0054] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via an 81 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation/deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and/or WCDMA

[0055] The SGW 164 may be connected to each of the eNode Bs 160a, 160b, 160c in the RAN 104 via the S1 interface. The SGW 164 may generally route and forward user data packets to/from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring user planes during inter-eNode B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like.

[0056] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0057] The CN 106 may facilitate communications with other networks For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers.

[0058] Although the WTRU is described in FIGS. 1A-1 D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network.

[0059] In representative embodiments, the other network 112 may be a WLAN.

[0060] A WLAN in 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 have access or an interface to a Distribution System (DS) or another type of wired/wireless network that carries traffic in to and/or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA The traffic between STAs within a BSS may be considered and/or referred to as peer-to-peer traffic. The peer-to- peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11e DLS or an 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an “ad-hoc” mode of communication.

[0061] When using the 802.11ac infrastructure mode of operation or a similar mode of operations, the AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width. The primary channel may be the operating channel of the BSS and may be used by the STAs to establish a connection with the AP. In certain representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) may be implemented, for example in 802.11 systems. For CSMA/CA, the STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed/detected and/or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0062] High Throughput (HT) STAs may use a 40 MHz wide channel for communication, for example, via a combination of the primary 20 MHz channel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHz wide channel.

[0063] Very High Throughput (VHT) STAs may support 20MHz, 40 MHz, 80 MHz, and/or 160 MHz wide channels The 40 MHz, and/or 80 MHz, channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two noncontiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, the data, after channel encoding, may be passed through a segment parser that may divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing, and time domain processing, may be done on each stream separately The streams may be mapped on to the two 80 MHz channels, and the data may be transmitted by a transmitting STA. At the receiver of the receiving STA, the above described operation for the 80+80 configuration may be reversed, and the combined data may be sent to the Medium Access Control (MAC).

[0064] Sub 1 GHz modes of operation are supported by 802.11 af and 802.11 ah. The channel operating bandwidths, and carriers, are reduced in 802.11af and 802.11ah relative to those used in 802.11n, and 802.11ac. 802.11 af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11 ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11 ah may support Meter Type Control/Machine- Type Communications (MTC), such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g , only support for) certain and/or limited bandwidths The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).

[0065] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802 11 n, 802.11ac, 802.11af, and 802.11 ah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and/or limited by a STA, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode. In the example of 802.11ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes. Carrier sensing and/or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode) transmitting to the AP, all available frequency bands may be considered busy even though a majority of the available frequency bands remains idle. [0066] In the United States, the available frequency bands, which may be used by 802.11 ah, are from 902 MHz to 928 MHz. In Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11 ah is 6 MHz to 26 MHz depending on the country code.

[0067] FIG. 1 D is a system diagram illustrating the RAN 104 and the GN 106 according to an embodiment. As noted above, the RAN 104 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0068] The RAN 104 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 104 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 108b may utilize beamforming to transmit signals to and/or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and/or gNB 180c).

[0069] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, the OFDM symbol spacing and/or OFDM subcarrier spacing may vary for different transmissions, different cells, and/or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing a varying number of OFDM symbols and/or lasting varying lengths of absolute time).

[0070] 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 the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs 102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor point. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration WTRUs 102a, 102b, 102c may communicate with/connect to gNBs 180a, 180b, 180c while also communicating with/connecting to another RAN such as eNode-Bs 160a, 160b, 160c. For example, WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In the non- standalone configuration, eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs 102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional coverage and/or throughput for servicing WTRUs 102a, 102b, 102c.

[0071] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and/or DL, support of network slicing, DC, interworking between NR and E-UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control plane information towards Access and Mobility Management Function (AMF) 182a, 182b and the like. As shown in FIG. 1D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0072] The CN 106 shown in FIG. 1 D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While the foregoing elements are depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator.

[0073] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different protocol data unit (PDU) sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of non-access stratum (NAS) signaling, mobility management, and the like. Network slicing may be used by the AMF 182a, 182b in order to customize CN support for WTRUs 102a, 102b, 102c based on the types of services being utilized WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for MTC access, and the like The AMF 182a, 182b may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and/or non-3GPP access technologies such as WiFi.

[0074] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 106 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 106 via an N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b The SMF 183a, 183b may perform other functions, such as managing and allocating WTRU IP address, managing PDU sessions, controlling policy enforcement and QoS, providing DL data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernet-based, and the like.

[0075] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering DL packets, providing mobility anchoring, and the like. [0076] The CN 106 may facilitate communications with other networks For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local DN 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0077] In view of FIGs. 1A-1 D, and the corresponding description of FIGs. 1A-1 D, one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and/or any other device(s) described herein, may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and/or to simulate network and/or WTRU functions.

[0078] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and/or in an operator network environment. For example, the one or more emulation devices may perform the one or more, or all, functions while being fully or partially implemented and/or deployed as part of a wired and/or wireless communication network in order to test other devices within the communication network. The one or more emulation devices may perform the one or more, or all, functions while being temporarily implemented/deployed as part of a wired and/or wireless communication network The emulation device may be directly coupled to another device for purposes of testing and/or performing testing using over-the-air wireless communications.

[0079] The one or more emulation devices may perform the one or more, including all, functions while not being implemented/deployed as part of a wired and/or wireless communication network. For example, the emulation devices may be utilized in a testing scenario in a testing laboratory and/or a non-deployed (e.g., testing) wired and/or wireless communication network in order to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and/or wireless communications via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and/or receive data. Acronyms and abbreviations as used in the preceding and following paragraphs may be defined as follows:

ACK Acknowledgement

BLER Block Error Rate

BWP Bandwidth Part

CAP Channel Access Priority

CAPC Channel access priority class

CCA Clear Channel Assessment

CCE Control Channel Element

CE Control Element

CG Configured grant or cell group

CP Cyclic Prefix CP-OFDM Conventional OFDM (relying on cyclic prefix) CQI Channel Quality Indicator CRC Cyclic Redundancy Check CSI Channel State Information CW Contention Window CWS Contention Window Size CO Channel Occupancy C-RNTI Cell RNTI DAI Downlink Assignment Index DC I Downlink Control Information DFI Downlink feedback information DG Dynamic grant DL Downlink DM-RS Demodulation Reference Signal DRB Data Radio Bearer eLAA enhanced Licensed Assisted Access FeLAA Further enhanced Licensed Assisted Access GEO Geo-stationary Orbit HARQ Hybrid Automatic Repeat Request LAA License Assisted Access LBT Listen-Before-T alk LEO Low Earth Orbit LTE Long Term Evolution e.g. from 3GPP LTE R8 and up NACK Negative ACK MCS Modulation and Coding Scheme MIMO Multiple Input Multiple Output NR New Radio NT Non-terrestrial Network OFDM Orthogonal Frequency-Division Multiplexing PDCCH Physical Downlink Control CHannel PDSCH Physical Downlink Shared CHannel PHY Physical Layer PID Process ID PO Paging Occasion PRACH Physical Random Access Channel PSS Primary Synchronization Signal PUCCH Physical Uplink Control CHannel PUSCH Physical Uplink Shared CHannel RA Random Access (or procedure) RACH Random Access Channel RAR Random Access Response RCU Radio access network Central Unit RF Radio Front end RLF Radio Link Failure RLM Radio Link Monitoring RNTI Radio Network Identifier RO RACH occasion RRC Radio Resource Control RRM Radio Resource Management RS Reference Signal RSRP Reference Signal Received Power RSSI Received Signal Strength Indicator SDU Service Data Unit SRS Sounding Reference Signal SS Synchronization Signal SSS Secondary Synchronization Signal

SWG Switching Gap (in a self-contained subframe)

SPS Semi-persistent scheduling

SUL Supplemental Uplink

TB Transport Block

TBS T ransport Block Size

TC-RNTI Temporary C-RNTI

TRP Transmission / Reception Point

TSC Time-sensitive communications

TSN Time-sensitive networking

UL Uplink

URLLC Ultra-Reliable and Low Latency Communications

WBWP Wide Bandwidth Part

WLAN Wireless Local Area Networks and related technologies (IEEE 8O2.xx domain)

[0080] Terms defined further herein may be referred to using various different notations. Hereinafter, 'a’ and ’an’ and similar phrases may be interpreted as ‘one or more’ and 'at least one’. Similarly, any term which ends with the suffix ‘(s)’ may be interpreted as 'one or more’ and ‘at least one’. The term ‘may’ is to be interpreted as 'may, for example’.

[0081] Random access may be performed either in a contention-based fashion (i.e., contention based random access (CBRA) and contention free (i.e., contention free random access (CERA)). Two types of random access are supported in NR: four-step RA, and two-step RA. The two-step RACH procedure is useful in scenarios where latency is important, as the signaling exchange necessary to complete the random access procedure is reduced.

[0082] The four-step and two-step procedures are described herein in with reference to FIGS. 2 and 3, respectively.

[0083] A four-step random access procedure may be implemented as follows, and as shown in FIG. 2. At 210, four-step random access begins with a WTRU transmitting MSG1, which contains a preamble on PRACH. Upon MSG1 transmission, the WTRU monitors for a random access response (e.g. RAR/Msg2) from the network within a configured window. At 212, upon reception of the RAR, which contains an UL grant and a timing advance command, the WTRU applies the timing advance command and at 214 sends Msg3 using the UL grant provided in RAR. Upon Msg3 transmission, the WTRU again monitors for a network response (e.g. Msg4) containing contention resolution information. If contention resolution is successful at 216, random access is complete and the WTRU begins connection. If contention resolution fails, the WTRU restarts random access via transmission of Msg1 , i.e. 210 is repeated.

[0084] A two-step random access procedure may be implemented as follows and as shown in FIG. 3. Two- step random access begins with transmission of MsgA, which includes a preamble 310 on PRACH and a payload 312 on PUSCH. After MsgA transmission, the WTRU monitors for a response (e g. MsgB) from the network within a configured window containing information regarding contention resolution. At 314, if contention resolution is successful, the WTRU terminates the random access procedure If contention resolution fails and a fallback indication is provided in MsgB, the WTRU may perform Msg3 transmission using an UL grant contained within the MsgB fallback indication, and begin to monitor for contention resolution. If contention resolution again fails after Msg3 transmission, the WTRU reverts back to MsgA transmission. If the MsgA transmission fails a configured number of times, the WTRU may revert back to four-step Random access.

[0085] Which type of random access is used (two-step or four-step) is selected upon initiation of the random access procedure based on network configuration. When contention-free random access resources are configured, a WTRU performs four-step or two-step random access depending on whether the random access resources correspond to two-step or four-step If contention-free random access resources are not provided, the WTRU selects between four-step and two-step random access based on an RSRP threshold.

[0086] Upon Random Access Preamble transmission, the MAC entity will start the ra-ResponseWindow at a PDCCH occasion. While the ra-ResponseWindow is running, the WTRU may monitor PDCCH. Upon successful RAR reception containing Random Access Preamble identifiers that match the transmitted PREAMBLE JNDEX, the MAC entity may stop ra-ResponseWindow and hence monitoring for Random Access Response(s).

[0087] As shown in FIG 4, after the RA preamble transmission 410, the ra-ResponseWindow 412 and RAR 414 or Blind Msg3 Retransmission Grant 422, upon Msg3 (re)transmission, 418, 426 the MAC entity will start the ra-ContentionResolutionTimer 420, 428 in the first symbol after the end of Msg3 (re)transmission 418, 426. While the ra-ContentionResolutionTimer is running (420, 428), the WTRU may monitor PDCCH. The MAC entity will stop the ra-ContentionResolutionTimer if notification of a reception of a PDCCH transmission is received from lower layers and the PDCCH transmission is addressed to C-RNTI or TEMPORARY_C-RNTI 430. Processing time between the receipt of the RAR or Blind Ms3 Retransmission Grant is shown in FIG 4 as 416, 424.

[0088] To improve NR uplink coverage for both FR1 and FR2, several enhancements for MSG3 PUSCH may be supported. These include: MSG3 repetition, wherein Aggregation of multiple slots with TB repetition for MSG3 transmission may be supported on both NUL and SUL, applicable to CBRA with 4-step RA type. If configured, the WTRU may request MSG3 repetition via separate PRACH resource when the RSRP of DL path-loss reference is lower than a configured threshold, and Blind MSG3 retransmission: wherein the network may send a separate grant to retransmit MSG3 prior to the decoding result of the initial transmission

[0089] WTRU-gNB RTT calculation and pre-compensation in non-terrestrial networks may be implemented as follows. Due to the altitude of NTN platforms and beam diameter, the round-trip time (RTT) and maximum differential delay is significantly larger than that of terrestrial systems. In a typical NTN deployment, RTT can range from 25.77 ms (LEO @ 600km altitude) to 541.46 ms (GEO) and maximum differential delay from 3.12 ms to 10.3 ms. To minimize impact to existing NR systems (e.g. to avoid preamble ambiguity or properly time reception windows), prior to initial access a WTRU may perform timing pre-compensation. The timing precompensation procedure requires the WTRU to obtain its position via GNSS, and the feeder-link (or common) delay and satellite position via satellite ephemeris data. The satellite ephemeris data is periodically broadcast in system information, and contains the satellite speed, direction, and velocity. The WTRU may then estimate the distance (and thus delay) from the satellite, and then add the feeder-link delay component to obtain the full WTRU-gNB RTT, which is then used to offset timers, reception windows, or timing relations.

[0090] Adaptations to PDCCH monitoring for non-terrestrial networks may be implemented as follows. PDCCH monitoring during random access may modified for non-terrestrial networks by offsetting the start of ra-ResponseWindow, msgB-ResponseWindow, and ra-ContentionResolutionTimer b the WTRU-gNB RTT. This may ensure that the ra-ResponseWindow and ra-ContentionResolutionTimer do not prematurely expire due to the long propagation delays characteristic of non-terrestrial networks.

[0091] Adaptations to MSG3 coverage enhancements for non-terrestrial networks may be implemented as follows. Both Msg3 coverage enhancement techniques may be supported for NTN For example, Type A PUSCH repetition is supported by starting the ra-ContentionResolutionTimer in the first symbol after the end of all repetitions of the Msg3 transmission plus the WTRU-gNB RTT. Blind Msg3 retransmission is supported by ignoring ra-ContentionResolutionTimer expiry if a PDCCH addressed to TC-RNTI indicating an UL grant for a Msg3 retransmission is received after the start of the ra-ContentionResolutionTimer.

[0092] As illustrated in FIG. 4, in terrestrial networks the gap 416 between a MAC entity stopping 414 the ra-ResponseWindow 412 and starting the ra-ContentionResolutionTimer 420 is usually quite brief, allowing near-continuous monitoring of PDCCH FIG 5 shows offsetting the start 520 of the ra- ContentionResolutionTimer 522 in NTN such that the gap including processing time 514 and the additional time 518 is significantly increased, limiting the ability to quickly receive a blind Msg3 retransmission grant after the ra-ResponseWindow 510 is stopped 512.

[0093] The additional delay means that the network may not schedule a blind MSG3 retransmission until at least the WTRU-gNB RTT, limiting scheduler flexibility and increasing latency of the RA procedure. Furthermore, MSG3 repetition may not always be a suitable solution in NTN considering the RACH congestion caused by a large number of WTRUs simultaneously performing RACH, which can place limitations on the resources needed to perform multiple consecutive repetitions.

[0094] A WTRU may continue monitoring PDCCH between RA windows, however a blind retransmission grants 422 is opportunistic, and the network may always choose not to provide one. Considering the WTRU- gNB RTT 518 can be quite long, this can result in additional and unnecessary WTRU power consumption.

[0095] In embodiments, general solution components to support blind MSG3 retransmission enhancements in non-terrestrial networks are shown schematically in FIG 6 and, for example, may include: a preamble transmission 610 which may optionally indicate WTRU coverage conditions (e.g. from a partition of preamble indices or RACH occasions); a trigger condition 612 to perform additional PDCCH monitoring for blind retransmission grant reception; an optional configuration 614 for a WTRU to override 620 a triggered additional monitoring occasion based on an override decision 616; and performing additional PDCCH monitoring 618 for blind MSG3 retransmission grant reception. The following is an exemplary description of embodiments wherein these component solutions may be combined. [0096] The term “fast blind MSG3 retransmission grant reception” as used herein refers to reception of a retransmission grant earlier than WTRU-gNB RTT after the initial Msg3 transmission. The solutions described herein may apply to any device operating in a non-terrestrial network (e.g. a NTN WTRU, VSAT terminal, NB- loT and/or eMTC device) or in other network deployments with large WTRU-gNB RTT.

[0097] The embodiments described herein may be primarily directed to additional PDCCH monitoring occasions after initial MSG3 transmission in non-terrestrial networks, however embodiments described herein may also apply to support blind retransmission grant reception for transmissions other than MSG3 transmission (e g., other RRC messages or even user plane data).

[0098] Channel conditions may refer to any conditions relating to the state of the radio/channel, which may be determined by the WTRU from: a WTRU measurement (e.g., L1/SI NR/RSRP, CQI/MCS, channel occupancy, RSSI, power headroom, exposure headroom), L3/mobility-based measurements (e.g. RSRP, RSRQ), an RLM state, and/or channel availability in unlicensed spectrum (e.g whether the channel is occupied based on determination of an LBT).

[0099] PRACH resource herein refers to a PRACH resource (e.g., in frequency), a PRACH occasion (RO) (e g., in time), a preamble format (e.g., in terms of total preamble duration, sequence length, guard time duration and/or in terms of length of cyclic prefix) and/or a certain preamble sequence used for the transmission of a preamble in a random-access procedure.

[0100] A property of scheduling information (e.g., an uplink grant or a downlink assignment) may, for example, include at least one of the following: a frequency allocation; an aspect of time allocation, such as a duration; a priority; a modulation and coding scheme; a transport block size; a number of spatial layers; a number of transport blocks to be carried; a TCI state or SRI; a number of repetitions; and whether the grant is a configured grant type 1 , type 2 or a dynamic grant.

[0101] An indication by DCI, or an indication, may, for example, include at least one of the following: an explicit indication by a DCI field or by RNTI used to mask CRC of the PDCCH; an implicit indication by a property such as DCI format, DCI size, coreset or search space, aggregation level, identity of first control channel resource (e.g., index of first CCE) for a DCI, where the mapping between the property and the value may be signaled by RRC or MAC; and an explicit indication by a DL MAC CE.

[0102] The following considerations are addressed via the embodiments provided herein: WTRU power saving (i.e., ensuring that a WTRU is performing additional monitoring only when a blind retransmission grant is expected ); limited ability to signal/indicate a blind retransmission grant is expected since opportunity for DL signaling is limited; that WTRU coverage scenario may vary greatly due to cell size in NTN, which may complicate broadcast signaling; and that different scenarios (e.g. two-step RACH fallback, RACH in CONN vs. IDLE/INACTIVE, loT NTN vs. NR NTN, priority of access attempt, number of failed RACH attempts, distance from cell center etc..) may require differentiated WTRU behavior.

[0103] The following common benefits may result from the embodiments described herein: allowing the WTRU to perform limited additional PDCCH monitoring during random access; allowing a trade-off between WTRU power consumption; and additional scheduler flexibility of the network. This ensures the WTRU is monitoring for a blind MSG3 retransmission grant only when one is expected, or in scenarios when one is most needed.

[0104] In some embodiments, a WTRU may use one or more of the solutions described below to indicate, for example, one or more of the following: The WTRU supports additional monitoring for enhanced blind MSG3 retransmission (e.g. the WTRU supports this as a WTRU capability); the WTRU is in a coverage limited scenario (e g. the WTRU could benefit from additional coverage enhancements such as additional blind MSG3 retransmission); and the WTRU may perform additional monitoring for a blind MSG3 retransmission grant; the WTRU may request an additional blind MSG3 retransmission grant.

[0105] A WTRU may report capability and/or coverage characteristics by implicit indication of capability for enhanced blind MSG3 retransmission. A WTRU may request, indicate its capability, its coverage scenario, or that it will perform additional monitoring for enhanced blind MSG3 retransmission via an implicit indication wherein the WTRU may use a particular PRACH preamble during RA procedure. The preamble may be within a set of PRACH preambles reserved/associated for/with such WTRUs.

[0106] A WTRU may request, indicate its capability, its coverage scenario, or that it will perform additional monitoring for enhanced blind MSG3 retransmission via an implicit indication wherein the WTRU may send the PRACH at a particular random-access occasion (e.g., within a set of RACH occasions that are reserved/associated for/with such WTRUs. WTRU may request, indicate its capability, its coverage scenario, or that it will perform additional monitoring for enhanced blind MSG3 retransmission via an implicit indication wherein the WTRU may use a combination of PRACH preamble and random-access occasion.

[0107] A WTRU may request, indicate its capability, its coverage scenario, or that it will perform additional monitoring for enhanced blind MSG3 retransmission via an implicit indication wherein the WTRU may send the PRACH preamble more than once (e.g., twice) to indicate that it supports the opportunistic blind Msg3 retransmission, for example sends a preamble transmission in more than one RO (e g. a specific combination) or using more than one preamble.

[0108] A WTRU may report capability and/or coverage characteristics by explicit indication of WTRU capability for enhanced blind MSG3 retransmission wherein, the WTRU may send the indication to the network via explicit signaling (e.g. via RRC, MAC CE, UCI, RACH message). The explicit indication may be a flag (e.g., to indicate that the WTRU supports additional monitoring for blind MSG3 retransmission grant), a field which can indicate one or more aspects (e.g., that the WTRU is in a coverage limited scenario and supports additional monitoring), or an index which points to one or more preconfigured meanings. In one example, the WTRU may include this indication within a RACH message, such as within a MSGA PUSCH resource. The WTRU can, for example, indicate that the WTRU supports additional blind MSG3 retransmission and/or will perform additional monitoring in case the WTRU may fall back to four-step RACH. In another example, the WTRU may include an indication via RRC signaling, such as within a WTRU capability transfer (e.g., during connection to RRC connected mode). The WTRU may apply the indicated behavior, for example, for a subsequent random-access procedure. In another solution, the WTRU may include this information within a WTRU information response message (e.g in response to a WTRU information request message).

[0109] A WTRU may report capability and/or coverage characteristics by conditional indication of capability for enhanced blind MSG3 retransmission wherein the WTRU may send the indication to the network depending on its power/battery level. For example, a WTRU that has such capability but having full battery (or, for example, or currently being charged), may refrain from sending this indication. In another example, the WTRU may send one indication that is associated with one range of power levels, and another indication that is associated with another range of power levels, etc.

[0110] A WTRU may report capability and/or coverage characteristics by conditional indication of capability for enhanced blind MSG3 retransmission wherein the WTRU may send the indication depending on whether it is coverage limited or not. For example, the WTRU may include the indication and/or select a PRACH partition associated with limited coverage in one or more of the following scenarios: Measurement/signal level-based determination of coverage: if the signal level of the serving cell (E.g., RSRP) is below a certain level but may refrain from doing so if the signal level of the serving cell is above a certain level. The WTRU may send one indication that is associated with one range of serving cell signal levels, and another indication that is associated with another range of serving cell signal levels, etc.

[0111] A WTRU may report capability and/or coverage characteristics by conditional indication of capability for enhanced blind MSG3 retransmission wherein if the distance between the WTRU’s location (e.g. acquired via GNSS) and the serving satellite is above a threshold, but may refrain from doing so if the signal level of the serving cell is above a certain level. If the distance between the WTRU’s location (e.g. acquired via GNSS) and the serving cell reference point is above a threshold, but may refrain from doing so if the signal level of the serving cell is above a certain level.

[0112] In another embodiment, the WTRU may send the indication to the network depending on its mobility state. For example, the WTRU may include the indication if it is in high mobility state but refrain from doing so otherwise. In another example, the WTRU may send one indication that is associated with low mobility sate, another indication that is associated with a medium mobility state, another indication that is associated with high mobility state, etc.

[0113] In another embodiment, the WTRU may send the indication depending on an indication received in broadcast signaling. For example, the network may enable blind MSG3 retransmission by including an indication in a system information block and if the WTRU receives this indication then the WTRU may send the capability indication. In some examples, the network may indicate a type of blind retransmission (for example, different modes of operation or different parameters) which is enabled, and the WTRU may determine whether or not the WTRU supports the indicated type and based on this determination may send the capability indication. In some examples the presence of any type of configuration information related to blind Msg3 retransmission is used to implicitly determine whether the network has enabled this feature, and whether the WTRU may send an indication of capability. [0114] Additional PDCCH monitoring for enhanced blind MSG3 retransmission grant reception may be predefined, configured by the network, and/or explicitly indicated. Such configurations can be used to support one or more of the solutions described here, and may include of one or more of the following: the preambles or RACH occasions associated with such capability, and any dependency on coverage limitation, battery level or mobility state, etc., described previously; an indication to perform additional monitoring for blind MSG3 retransmission (e g. an enable/disable configuration); mapping between characteristics of the MSG3 retransmission behavior and additional monitoring for blind MSG3 retransmission; conditions to perform additional blind MSG3 retransmissions (e.g., associated thresholds and/or range of thresholds); whether to perform additional monitoring based on a failure case (e.g. after fallback from two-step to four-step RACH, the number of transmission attempts before additional monitoring is needed etc.); conditions to override additional monitoring for blind MSG3 retransmission grant (e.g thresholds, prohibit timer durations); and/or characteristics of how additional monitoring should be performed (e.g. start, duration, periodicity).

[0115] A WTRU may be configured to monitor (receive) PDCCH in a set of occasions during the random access procedure. The WTRU may determine a set of PDCCH monitoring occasions by monitoring according to DRX for Random Access configuration, wherein in an embodiment, the WTRU may determine the set of PDCCH monitoring occasions according to at least one DRX configuration and operation. Such DRX configuration may be referred to as DRX for Random Access. The WTRU may receive parameters for at least one of a DRX on-duration timer, a DRX inactivity timer, a DRX long cycle and starting offset, a DRX short cycle, a DRX slot offset and the like. The WTRU may monitor PDCCH while at least one of the DRX on-duration timer or DRX inactivity timer is running. The WTRU may restart the inactivity timer upon reception of PDCCH scrambled with TC-RNTI.

[0116] A WTRU may determine a set of PDCCH monitoring occasions by monitoring according to time pattern, wherein in an embodiment, the WTRU may determine the set of PDCCH monitoring occasions according to a configured time pattern. The time pattern may include a repeating sequence of durations alternating between periods in which the WTRU monitors PDCCH (on durations) and periods in which the WTRU does not monitor PDCCH (off-durations). For example, a sequence may include two slots of on duration followed by twelve slots of off-duration. Such sequence may be indicated by a bitmap where each bit corresponds to a time duration (e.g. one slot) and the value of the bit indicates whether the time duration is an on-duration or off-duration. Alternatively, such sequence may be indicated by a time offset (duration) between a slot, subframe and/or symbol boundary and the start of an on-duration period and the duration of the on- duration period. The configuration may also include a periodicity over which the pattern is repeating.

[0117] A WTRU may determine a set of PDCCH monitoring occasions by signaling of configurations, wherein the WTRU may receive the value of at least one parameter of a configuration for PDCCH monitoring from RRC, MAC or DCI signaling. The WTRU may receive multiple configurations for PDCCH monitoring, each identified by an index, and receive indication of the applicable configuration from the signaling. One configuration may correspond to the WTRU monitoring PDCCH in every possible monitoring occasion, e g. in every slot. Configurations may be specific to, for example, one or more of the following: a cell (e.g. the serving cell); a group of cells; a satellite; and an orbit or orbital classification (e.g. GEO or LEO) For example, the WTRU may determine at least one value from system information, from a dedicated RRC message (RRC reconfiguration, RRC connection release), from a field of a random access response (RAR) message, or from a property of the RAR grant. For example, the WTRU may determine the value of periodicity, on-duration and/or configuration index from a number of most or least significant bits of a modulation and coding scheme (MCS) field or from a time domain resource allocation (TDRA) field or from a back-off indicator (Bl) field The mapping between the bits and the corresponding values may be pre-defined or may be signaled by RRC.

[0118] Where the WTRU determines a set of PDCCH monitoring occasions by signaling of configurations, the WTRU may determine the value of at least one parameter, or a configuration index, based on the same condition(s) used for the determination of the preamble or of the number of preamble repetitions For example, the WTRU may determine the value of a configuration index based on a path loss estimate or RSRP measurement taken on a resource such as SSB.

[0119] Where the WTRU determines a set of PDCCH monitoring occasions by signaling of configurations as described above, the at least one parameter or configuration index may be determined from a combination of the above solutions. For example, the WTRU may first determine a set of possible configuration index values associated to preamble selection and then determine the applicable configuration index value from this set from a field of the RAR.

[0120] The WTRU may determine a set of PDCCH monitoring occasions by configuration update upon DCI reception or based on the number of Msg3 repetitions/retransmissions. In embodiments, the WTRU may update the value of at least one parameter based on the reception of a DCI such as a DCI addressed to TC-RNTI. For example, the WTRU may apply a first PDCCH monitoring configuration upon reception of RAR and apply a second PDCCH monitoring configuration upon reception of DCI addressed to TC-RNTI. The WTRU may update the value based on information from both the DCI addressed to TC-RNTI and the DCI containing the RAR. For example, the WTRU may apply a first PDCCH monitoring configuration upon reception of RAR and apply a second PDCCH monitoring configuration upon reception of DCI addressed to T C-RNTI if the MCS indicated in the RAR is higher than the MCS indicated in the DCI addressed to TC-RNTI. In embodiments, the WTRU may update the value of at least one parameter or the configuration index when the number of Msg3 repetitions and/or retransmissions reaches a configured or pre-defined threshold. For example, the WTRU may monitor PDCCH in every possible monitoring occasion (e g. in every slot) if the number Msg3 repetitions or retransmissions exceeds 32.

[0121] A WTRU may apply a PDCCH monitoring pattern when one of the following occurs: reception of RAR; or start (or end) of initial transmission of Msg3 PUSCH. In embodiments, a WTRU may stop applying a PDCCH monitoring pattern when at least one of the following occurs: successful contention resolution; reception of PDCCH for C-RNTI; number of repetitions and/or retransmissions of Msg3 PUSCH reaches a predefined or configured threshold; RRC signaling (e g. connection setup or reconfiguration) indicating an appl icable DRX configuration; and/or after a configured or pre-defined period since the WTRU started to apply to monitoring pattern

[0122] In embodiments, a configuration/indicated by the network may be received with a first message and may then be enabled/disable by NW signaling (e.g., MAC CE, DCI, SIB, RRC, RACH message, etc.,) in a second message.

[0123] A WTRU may receive an indication from the network regarding additional PDCCH monitoring occasions/periods to check for grants for blind Msg3 retransmission. The WTRU then performs the PDCCH monitoring during the indicated occasions/periods after the initial transmission of Msg3.

[0124] A WTRU may receive an indication from the network regarding additional PDCCH monitoring occasions/periods to check for grants for blind Msg3 retransmission, wherein the WTRU may receive a configuration for a first PDCCH monitoring (e.g., normal PDCCH monitoring) for blind MSG3 retransmission.

[0125] A WTRU may receive an indication from the network regarding additional PDCCH monitoring occasions/periods to check for grants for blind Msg3 retransmission, wherein the WTRU may receive configuration information associated with performing, or an indication (e.g , explicit indication) to perform, second PDCCH monitoring (e.g., additional PDCCH monitoring) for blind MSG3 retransmission grant reception, where, in an example, the second PDCCH monitoring may be performed before the first PDCCH monitoring (the configuration information or indication may be provided in e.g. System Information, an RRC Release message, a Handover command and/or a RACH configuration; the configuration information or indication may include when and/or how to perform the second PDCCH monitoring (e.g. start new timer for X ms, monitor with a certain periodicity, start monitoring at Z offset from RAR reception or from MSG3 transmission)).

[0126] A WTRU may receive an indication from the network regarding additional PDCCH monitoring occasions/periods to check for grants for blind Msg3 retransmission, wherein the WTRU may select and transmit a PRACH preamble. Preambles may optionally be partitioned, and the WTRU may select a preamble which indicates at least one of: the WTRU is in a coverage limited scenario; the WTRU supports and/or will perform the second (e.g., additional) PDCCH monitoring; and a request for blind retransmission grants based on or using the second (e.g., additional) PDCCH monitoring.

[0127] A WTRU may receive an indication from the network regarding additional PDCCH monitoring occasions/periods to check for grants for blind Msg3 retransmission, wherein the WTRU may start the ra- ResponseWindow and monitor PDCCH for a Random Access Response.

[0128] A WTRU may receive an indication from the network regarding additional PDCCH monitoring occasions/periods to check for grants for blind Msg3 retransmission, wherein the WTRU may receive a Random Access Response and stop the ra-ResponseWindow In an example embodiment, the Random Access Response may include an indication (e.g., explicit indication) to perform the second (e.g., additional) PDCCH monitoring for blind MSG3 retransmission grant. The indication may activate or indicate to the WTRU to perform the second PDCCH, e.g., according to configuration information. [0129] A WTRU may receive an indication from the network regarding additional PDCCH monitoring occasions/periods to check for grants for blind Msg3 retransmission, wherein the WTRU may transmit at least one MSG3 based on the received RAR (e g., based on an UL grant received in the RAR).

[0130] A WTRU may receive an indication from the network regarding additional PDCCH monitoring occasions/periods to check for grants for blind Msg3 retransmission, wherein the WTRU may monitor PDCCH in monitoring occasions based on the received configuration and/or indication for the second PDCCH monitoring for blind MSG3 retransmission grant. In embodiments these may be at second or additional occasions.

[0131] A WTRU may receive an indication from the network regarding additional PDCCH monitoring occasions/periods to check for grants for blind Msg3 retransmission, wherein when the WTRU receives a PDCCH based on the second PDCCH monitoring, the WTRU retransmits at least one MSG3, e.g., based on a grant received in the PDCCH (e.g., in the DCI carried by the PDCCH).

[0132] A WTRU may receive an indication from the network regarding additional PDCCH monitoring occasions/periods to check for grants for blind Msg3 retransmission, wherein, after monitoring for PDCCH based on the second PDCCH monitoring, the WTRU may monitor for PDCCH based on the first PDCCH monitoring and transmits at least one MSG3 when a PDCCH (e.g., with an UL grant) is received.

[0133] In embodiments, a WTRU may receive an explicit indication, for example, via one or more of the following: a Random Access Response (e.g., msg2); a PDCCH order; SIB signaling (e.g. SIB19, SIB31 , and/or SIB 32); a paging message (e g., CN paging, RAN paging, etc.,) that, for example, indicates to the WTRU the arrival of DL data while the WTRU is in IDLE/I NACTIVE; a Handover Command (E.g., within the reconfigurationWithSync IE of the RRC reconfiguration message); an RRC release message when the WTRU is transitioned from connected state to IDLE/I NACTIVE; an RRC reconfiguration message that is neither a HO command nor an RRC release.

[0134] In embodiments, a WTRU may receive an explicit indication, wherein the WTRU may be configured to use the received indication/configuration only if it transitions to a CONNECTED state within the validity time. [0135] In embodiments, a WTRU may receive an explicit indication, wherein, a validity area (e.g., list of cells, frequencies, etc.) may be associated with the indication. For example, the WTRU may use the indication only if it has not performed cell re-selection outside the validity area.

[0136] In embodiments, a WTRU may receive an explicit indication, wherein the indication includes exact timing information when the grants for Msg3 retransmission are expected to be received in the PDCCH (e.g., exact frames/slots, etc.).

[0137] In embodiments, a WTRU may receive an explicit indication, wherein the indication includes a window of time wherein the grants for Msg3 retransmission are expected to be received in the PDCCH (E.g., between frames/slots n and m, between time t1 and t2, etc.). In one solution, the indication may include timing information for the grants for multiple retransmissions. For example, the indication may include periodic information (e.g., grant expected every n frame/slot from the reception of the indication or some other timepoint). For example, the indication may be aperiodic or quasi periodic (e.g., grants expected at t1, t2, t3, ... etc., where the duration between t1 and t2, and that between t2 and t3 is different).

[0138] In embodiments, a WTRU may receive an explicit indication, wherein the indication may be an agreed upon configuration that is dependent on the indication received from the WTRU that indicated the capability and conditions/needs of the WTRU. For example, for a particular PRACH preamble or PRACH occasion that is used by the WTRU (which, as described herein may be dependent on WTRU capability/conditions/needs), the WTRU will know when to monitor the PDCCH for grants for MSG3 retransmission. The WTRU may be pre-configured with this mapping between the indication from the WTRU and the PDCCH monitoring occasions/durations/windows for MSG3 (e.g., mapping specified in the 3GPP standards, mapping indication in SIB, RRC signaling, MAC signaling, etc.).

[0139] The above-described embodiments wherein additional PDCCH monitoring is triggered by explicit indication and/or configuration are further described below and with respect to exemplary flow diagram FIG. 7. [0140] At 710 a WTRU receives configuration for first PDCCH monitoring (e.g., normal PDCCH monitoring) for MSG3 retransmission.

[0141] At 712 the WTRU receives configuration information associated with performing, or an indication (e g., explicit indication) to perform, second PDCCH monitoring (e.g., additional PDCCH monitoring) for blind MSG3 retransmission grant reception, where, in an example, the second PDCCH monitoring may be performed before the first PDCCH monitoring. The configuration information or indication may be provided in e.g. System Information, an RRC Release message, a Handover command and/or a RACH configuration. The configuration information or indication may include when and/or how to perform the second PDCCH monitoring (e.g. start new timer for X ms, monitor with a certain periodicity, start monitoring at Z offset from RAR reception or from MSG3 transmission).

[0142] At 714 the WTRU selects and transmits a PRACH preamble. Preambles may optionally be partitioned, and the WTRU may select a preamble which indicates at least one of: the WTRU is in a coverage limited scenario; the WTRU supports and/or will perform the second (e.g., additional) PDCCH monitoring; and a request for blind retransmission grants based on or using the second (e.g., additional) PDCCH monitoring.

[0143] At 716 the WTRU starts the ra-ResponseWindow and monitors PDCCH for a Random Access Response.

[0144] At 718 the WTRU receives a Random Access Response and stops the ra-ResponseWindow. In an example, Random Access Response may include an indication (e.g., explicit indication) to perform the second (e g., additional) PDCCH monitoring for blind MSG3 retransmission grant. The indication may activate or indicate to the WTRU to perform the second PDCCH, e.g., according to configuration information.

[0145] At 720 the WTRU transmits at least one MSG3 based on the received RAR (e.g., based on an UL grant received in the RAR). [0146] At 771 the WTRU monitors PDCCH in monitoring occasions based on the received configuration and/or indication for the second PDCCH monitoring (e.g. , at second or additional occasions) for blind MSG3 retransmission grant.

[0147] At 724, when the WTRU receives a PDCCH based on the second PDCCH monitoring, the WTRU retransmits at least one MSG3, e.g., based on a grant received in the PDCCH (e.g., in the DCI carried by the PDCCH).

[0148] In embodiments, at 726, after monitoring for PDCCH based on the second PDCCH monitoring, the WTRU monitors for PDCCH based on the first PDCCH monitoring and transmits at least one MSG3 when a PDCCH (e.g., with an UL grant) is received.

[0149] A WTRU may perform additional PDCCH monitoring which is triggered based on Msg3 repetition characteristics, wherein the WTRU may perform additional PDCCH monitoring for enhanced blind MSG3 retransmission grant based on the characteristics of MSG3 repetition. A WTRU may have different behavior based on whether the WTRU is performing random access in RRC I D LE/I N ACT IVE or in RRC CONNECTED. [0150] In embodiments, a WTRU may perform additional PDCCH monitoring which is triggered based on Msg3 repetition characteristics as shown in FIG. 8. At 810, the WTRU receives configuration for first PDCCH monitoring (e.g., normal PDCCH monitoring) for MSG3 retransmission. At 812, the WTRU receives configuration information associated with performing second PDCCH monitoring (e.g., additional PDCCH monitoring) for blind MSG3 retransmission grant reception, where, in an example, the second PDCCH monitoring may be performed before the first PDCCH monitoring. At 814, the WTRU selects and transmits a PRACH preamble. Preambles may optionally be partitioned, and WTRU may select a preamble which indicates at least one of: the WTRU is in coverage limited scenario; WTRU supports and/or will perform the second (e.g., additional) PDCCH monitoring; a request for blind retransmission grants based on or using the second (e.g., additional) PDCCH monitoring. At 816, the WTRU starts the ra-ResponseWindow and monitors PDCCH for a Random Access Response. At 818, the WTRU receives a Random Access Response (RAR) indicating MSG3 repetition and stops the ra-ResponseWindow. The number of MSG3 repetitions to perform may be indicated by or determined from the contents of the RAR and/or may be based on a received configuration. At 820, the WTRU transmits at least one MSG3 based on the received RAR (e.g., based on UL grant received in the RAR). At 822, the WTRU determines based on at least one MSG3 repetition characteristic and/or an override condition whether to perform the second (e.g , additional) PDCCH monitoring for blind MSG3 retransmission. In an embodiment, an MSG3 characteristic is the number of MSG3 repetitions configured or indicated. A relation between performing second (e.g., additional) PDCCH monitoring and number of MSG3 repetitions may be predefined, configured (e.g. in RACH config, RRC Release message, or HO command) or indicated e.g. in system information or RAR. In an example, the relation may identify to perform the second PDCCH monitoring when the number of MSG3 repetitions is above or below a defined or configured value or threshold. In an embodiment, an override condition may be configured. An override condition may be, for example, based on an RSRP or distance threshold (e.g , provided in SIB, RRC Messages, RRC Release, etc.) and when, for

- 77 - example, the RSRP is above the RSRP threshold and/or the distance to the satellite (e.g., from the WTRU) is within (e.g., below) the distance threshold (e.g., X km.) If the condition is satisfied, WTRU does not perform the second (e g., additional) PDCCH monitoring.

[0151] If characteristics of MSG3 repetition indicate to perform the second (e.g., additional) monitoring, and/or the optional override conditions are not satisfied, at 824, the WTRU monitors PDCCH in monitoring occasions (e.g., based on the received configuration) for second PDCCH monitoring (e.g., at second or additional occasions) for blind MSG3 retransmission grant When the WTRU receives a PDCCH based on the second PDCCH monitoring, at 826, the WTRU retransmits at least one MSG3 based on the grant received in the PDCCH (e.g., the PDCCH DCI). In further embodiments, at 828, after monitoring for PDCCH based on the second PDCCH monitoring, the WTRU monitors for PDCCH based on the first PDCCH monitoring and transmits at least one MSG3 when a PDCCH (e.g., PDCCH DCI) with an UL grant is received.

[0152] A WTRU may perform additional monitoring for blind MSG3 retransmission grant based on whether MSG3 repetition is indicated for a transmission. In an embodiment, if the WTRU receives an indication (e.g. within RAR) that MSG3 repetition is configured for the MSG3 transmission, the WTRU may perform additional monitoring for blind MGS3 retransmission grant. In another example, if the WTRU receives and indication (e.g. within RAR) that MSG3 repetition is configured for the MSG3 transmission, the WTRU may not perform additional monitoring for blind MSG3 retransmission grant. The indication may be, for example, a flag, or a repurposed MCS codepoint which may be re-interpreted to trigger additional monitoring.

[0153] Whether a WTRU performs additional monitoring for blind MSG3 transmission grantbased on MSG3 repetition characteristics can be based on configuration. For example, a configuration may be present in system information where additional monitoring may be explicitly enabled/d isabled, or alternatively the presence of the parameter can indicate additional monitor for blind retransmission is enabled. In another example, this indication/configuration may be provided via RRC signaling (e.g. the RRC Release, RRC Release with suspend, or RRC Reconfiguration), via a random access message (e.g. RAR, MSGB), MAC CE, paging message, or DCI.

[0154] Whether a WTRU performs additional monitoring for blind MSG3 transmission grantbased on MSG3 repetition characteristics can be based on configuration wherein a configuration/indication may describe behavior to apply, such as one or more of the following: the WTRU may perform additional monitoring if MSG3 retransmission is indicated; The WTRU may not perform additional monitoring if MSG3 retransmission is indicated; the method of additional monitoring the WTRU may perform; and characteristics of additional monitoring (e.g. start, duration, periodicity).

[0155] Whether a WTRU performs additional monitoring for blind MSG3 transmission grantbased on MSG3 repetition characteristics can be based on configuration wherein a WTRU may override a first configuration to perform additional monitoring for blind MSG3 retransmission grant based on MSG3 repetition characteristics due to a second indication/configuration. In one example, an indication (e.g within system information) may configure the WTRU to perform additional monitoring based on MSG3 repetition characteristics. The WTRU may receive a subsequent indication (e.g. within RAR or MSGB) to override the indication within system information, wherein the WTRU will not perform additional monitoring regardless of the MSG3 repetition characteristics.

[0156] A WTRU may perform additional monitoring for blind MSG3 retransmission grant based on whether MSG3 repetition is indicated for a transmission and the WTRU may perform one or more of the following: the WTRU may receive configuration for first PDCCH monitoring (e.g., normal PDCCH monitoring) for blind MSG3 retransmission. The WTRU may receive configuration information associated with performing second PDCCH monitoring (e.g., additional PDCCH monitoring) for blind MSG3 retransmission grant reception, where, in an example, the second PDCCH monitoring may be performed before the first PDCCH monitoring. The WTRU may select and transmit a PRACH preamble (Preambles may optionally be partitioned, and WTRU may select a preamble which indicates at least one of: the WTRU is in coverage limited scenario; WTRU supports and/or will perform the second (e.g., additional) PDCCH monitoring; a request for blind retransmission grants based on or using the second (e.g., additional) PDCCH monitoring ) The WTRU may start the ra-ResponseWindow and monitors PDCCH for a Random Access Response. The WTRU may receive a Random Access Response (RAR) which does not indicate MSG3 repetition and stops the ra-ResponseWindow. The WTRU may transmit at least one MSG3 based on the received RAR (e.g., based on UL grant received in the RAR). Based on the lack of MSG3 repetition, the WTRU may monitor PDCCH in monitoring occasions (e g., based on the received configuration) for second PDCCH monitoring (e.g., at second or additional occasions) for blind MSG3 retransmission grant.

[0157] A WTRU may receive a mapping between MSG3 repetition characteristics and additional monitoring for blind MSG3 retransmission grant reception Based on the configured mapping behavior, upon reception of a MSG3 grant the WTRU will determine additional blind MSG3 monitoring behavior based on the MSG3 retransmission characteristics In embodiments, whether the WTRU performs additional monitoring may be mapped to (i.e. be a function of) a specific number of MSG3 retransmissions. For example, a WTRU may be configured to perform additional monitoring for a MSG3 grant similar to T able 1 , below

Table 1

[0158] A WTRU may receive a mapping between MSG3 repetition characteristics and additional monitoring for blind MSG3 retransmission grant reception, wherein in further embodiments, additional monitoring characteristics (e.g. start, duration, periodicity) may be mapped to a specific number of MSG3 retransmissions. For example, a WTRU may be configured to perform additional monitoring for a MSG3 grant similar to Table 2 below:

Table 2

[0159] A WTRU may receive a mapping between MSG3 repetition characteristics and additional monitoring for blind MSG3 retransmission grant reception, wherein in further embodiments, the WTRU may receive mapping information for example, via RRC signalling or MAC GE. In one example, the WTRU may receive the information within a handover command (e.g. and RRC reconfiguration with sync message) to use for random access to a target cell.

[0160] A WTRU may perform additional PDCCH monitoring for enhanced MSG3 blind retransmission grant based on satisfaction of a condition and/or combination of conditions, for example as described in conjunction with FIG. 9.

[0161] At 910, a WTRU may receive configuration for first PDCCH monitoring (e.g., normal PDCCH monitoring) for MSG3 retransmission. At 912, the WTRU receives configuration information associated with performing second PDCCH monitoring (e.g., additional PDCCH monitoring) for blind MSG3 retransmission grant reception, where, in an example, the second PDCCH monitoring may be performed before the first PDCCH monitoring. At 914, the WTRU receives conditions to perform the second (e.g , additional) PDCCH monitoring for blind MSG3 retransmission. In an embodiment, conditions may be based on one or more values, for example, one or more of: distance from cell center, angle of satellite relative to earth, and/or RSRP. In a further embodiment, configuration or identification of which one or more values to evaluate and one or more associated thresholds (e.g., against which to evaluate the one or more values) may be, for example, provided in system information, a HO command, RRC release message, or RAR. At 916, the WTRU selects and transmits a RACH preamble. Preambles may optionally be partitioned, and WTRU may select a preamble which indicates at least one of: the WTRU is in a coverage limited scenario; the WTRU supports and/or will perform the second (e.g., additional) PDCCH monitoring; a request for blind retransmission grants based on or using the second (e.g., additional) PDCCH monitoring. At 918, the WTRU starts the ra-ResponseWindow and monitors PDCCH for a Random Access Response. At 920, the WTRU receives a Random Access Response and stops the ra-ResponseWindow. At 922, the WTRU transmits at least one MSG3 based on the received RAR (e.g., based on UL grant received in the RAR). At 924, the WTRU determines whether to perform the second (e.g., additional) PDCCH monitoring for blind MSG3 retransmission based on configured conditions (e g., based on whether one or more of the values are above or below its associated threshold). If one or more conditions for second (e.g., additional) PDCCH monitoring are satisfied, at 926, the WTRU monitors PDCCH in monitoring occasions (e.g., based on the received configuration) for second PDCCH monitoring (e.g., at second or additional occasions) for blind MSG3 retransmission grant. When the WTRU receives a PDCCH based on the second PDCCH monitoring, at 928, the WTRU retransmits at least one MSG3 based on the grant received in the PDCCH (e.g., PDCCH DCI). In embodiments, after monitoring for PDCCH based on the second PDCCH monitoring, at 930, the WTRU monitors for PDCCH based on the first PDCCH monitoring and transmits at least one MSG3 when a PDCCH (e.g., PDCCH DCI) with an UL grant is received

[0162] A WTRU may perform additional PDCCH monitoring for enhanced MSG3 blind retransmission grant based on satisfaction of a condition and/or combination of conditions, wherein conditions for additional PDCCH monitoring for enhanced blind MSG3 retransmission grant reception may include one or more of the following: a threshold, wherein, for example, the condition may be satisfied if the measured value is above, below, or equal to a threshold value; a specific value, wherein, for example, the condition may be satisfied if the measured value is equal to one or more indicated values; a range of values, wherein, for example, the condition may be satisfied if the measured value falls within a range. Alternatively, the condition may be satisfied if the measured value falls outside of an indicated range.

[0163] A WTRU may perform additional PDCCH monitoring for enhanced MSG3 blind retransmission grant based on satisfaction of a condition and/or combination of conditions, wherein a WTRU may be configured with a distance-based condition used to determine a parameter, behavior, etc. A distance may be defined as one or more of the following: the WTRU-satellite distance; the distance between the WTRU- satellite cell center; the distance between the WTRU and satellite footprint; the distance between the WTRU and a terrestrial-based gNB; or the distance between a WTRU and a reference point. A distance-based condition may be in the form of the WTRU reaching at least or at most a certain distance. For example: a WTRU’s distance is above a configured threshold; a WTRU’s distance is below a configured threshold; and/or a WTRU’s distance is between two configured thresholds. A distance-based condition may be in the form of a change in the WTRU’s distance. In embodiments, the condition may be that: a WTRU’s distance changes by an amount greater than a threshold, possibly within a configured time period/duration; a WTRU’s distance increased by an amount greater than a threshold, possibly within a configured time period/duration; a WTRU’s distance decreases by an amount greater than a threshold, possibly within a configured time period/duration; the change of the WTRU’s distance has increased by an amount greater than a threshold, possibly within a configured time period/duration; or the change of the WTRU’s distance has decreased by an amount greater than a threshold, possibly within a configured time period/duration.

[0164] A distance-based condition may be in the form of a time the WTRU spends at a certain distance. For example, a WTRU’s distance stays at the same value for at least a configured period of time; a WTRU’s distance stays within a configured range at least for a configured period of time; a WTRU’s distance changes by less than a configured amount over a configured period of time; and/or a WTRU has spent the most amount of time, within a configured period of time, at a certain distance [0165] A WTRU may perform additional PDCCH monitoring for enhanced MSG3 blind retransmission grant based on satisfaction of a condition and/or combination of conditions, wherein a WTRU may be configured with a speed-based condition used to determine a parameter, behavior, etc A speed-based condition may be in the form of the WTRU reaching at least or at most a certain speed. For example: a WTRU’s speed is above a configured threshold; a WTRU’s speed is below a configured threshold; and/or a WTRU’s speed is between two configured thresholds. A speed-based condition may be in the form of a change in the WTRU’s speed (e.g., acceleration/deceleration). In embodiments, the condition may be that: a WTRU’s speed changes by an amount greater than a threshold, possibly within a time period; a WTRU’s speed increased by an amount greater than a threshold, possibly within a time period; or a WTRU’s speed decreases by an amount greater than a threshold, possibly within a time period. A speed-based condition may be in the form of a time the WTRU spends at a certain speed. In embodiments, the condition may be that a WTRU’s speed stays at the same value for at least a configured period of time; a WTRU’s speed stays within a configured range at least for a configured period of time; a WTRU’s speed changes by more/less than a configured amount over a configured period of time

[0166] A WTRU may perform additional PDCCH monitoring for enhanced MSG3 blind retransmission grant based on satisfaction of a condition and/or combination of conditions, wherein a WTRU may be configured with a satellite-based condition based on used to determine a parameter, behavior, etc. In embodiments, satellitebased conditions may depend on satellite characteristics, which may be explicitly indicated or implicitly determined (e.g via the satellite ephemeris). In embodiments, satellite conditions may be based on one or more of the following: the differential delay within a cell (e.g. the differential delay is above, below, or within a range); the size and/or footprint of the cell (e.g. the cell footprint is above, below, or within a range); the remaining t-service of a cell (e.g. the remaining t-service is above, below, or within a range); a gap between t- service of a current cell and t-service start of a neighboring cell (e.g. whether there is continuous coverage or discontinuous coverage); whether the satellite payload is configured with earth fixed or earth moving beams; the orbital classification of the satellite (e.g. whether the satellite is GEO, LEO, MEO or HAPS); or the angle of the satellite with respect to the earth.

[0167] A WTRU may perform additional PDCCH monitoring for enhanced MSG3 blind retransmission grant based on satisfaction of a condition and/or combination of conditions, wherein a WTRU may perform additional PDCCH monitoring for enhanced MSG3 blind retransmission grant based on satisfaction of a condition and/or combination of conditions, wherein WTRU may be configured with a channel-based condition used to determine a parameter, behavior, etc. Embodiments of a channel-based condition may include one or more of: measuring a channel condition below or above a threshold (e.g. RSRP, RSRQ); applied TA estimate/WTRU-gNB RTT (e g. the applied timing pre-compensation is above, below, or within a range); and/or frequency compensation (e g. applied frequency compensation is above, below, or within a range).

[0168] A WTRU may perform additional PDCCH monitoring for enhanced MSG3 blind retransmission grant based on satisfaction of a condition and/or combination of conditions, wherein in cases where a WTRU condition may be evaluated at the WTRU with limited ability to coordinate with the network whether a condition is satisfied and the VVTRU performs additional monitoring, a correlation can exist between the WTRU coverage characteristics and/or WTRU location and the NW decision to use blind MSG3 retransmission. In embodiments, the WTRU may explicitly indicate that a condition has been satisfied (e.g. via transmission of a dedicated preamble, or within MSA PUSCH.

[0169] A WTRU may perform additional PDCCH monitoring for blind MSG3 retransmission grant based on a failure condition as described below and with reference to FIGS 10A and 10B. At 1012, the WTRU receives configuration information associated with performing second PDCCH monitoring (e.g., additional PDCCH monitoring) for blind MSG3 retransmission grant reception, where, in an example, the second PDCCH monitoring may be performed before the first PDCCH monitoring. At 1014, the WTRU initiates two-step random access by transmission of MSGA which includes a preamble and a PUSCH transmission. Preambles may optionally be partitioned, and WTRU may select a preamble which indicates at least one of the following WTRU information or WTRU requests: the WTRU is in coverage limited scenario; WTRU supports and/or will perform the second (e.g., additional) PDCCH monitoring; a request for blind retransmission grants based on or using the second (e.g , additional) PDCCH monitoring. The WTRU information and/or requests may be optionally included in the MSGA PUSCH. At 1016, the WTRU starts the msgB-ResponseWindow and monitors PDCCH for a MSGB carrying a Random Access Response. At 1018, the WTRU receives a Random Access Response, where the RAR triggers a fallback to four-step RA, and stops the msgB-ResponseWindow. At 1020, the WTRU transmits at least one MSG3 based on the received RAR (e.g., based on UL grant received in the RAR). In embodiments, at 1022, the WTRU evaluates an override condition, if configured. In embodiments, the override condition may be based on an RSRP or distance threshold (e g., provided in SIB, RRC Messages, RRC Release, etc.) and when the RSRP is above the RSRP threshold and/or the distance to the satellite (e.g., from the WTRU) is within (e.g., below) the distance thresholds (e.g., X km) If the override condition is satisfied, at 1024, the WTRU determines to not perform the second (e.g., additional) PDCCH monitoring. If the override condition is not satisfied, at 1026, the WTRU determines to perform the second (e.g., additional) PDCCH monitoring (based on the fallback trigger).

[0170] A WTRU may perform additional PDCCH monitoring for blind MSG3 retransmission grant based on a failure condition, wherein, in further embodiments, an example of which is shown in FIG 10B, based on fallback trigger, at 1030, the WTRU determines to perform the second (e.g., additional) PDCCH monitoring. If the WTRU determines to perform the second (e.g., additional) PDCCH monitoring: at 1032, the WTRU monitors PDCCH in monitoring occasions (e.g., based on the received configuration) for second PDCCH monitoring (e g., at second or additional occasions) for blind MSG3 retransmission grant. When the WTRU receives a PDCCH based on the second PDCCH monitoring, the WTRU retransmits at least one MSG3 based on the grant received in the PDCCH (e.g., PDCCH DCI). In embodiments, after monitoring for PDCCH based on the second PDCCH monitoring, the WTRU monitors for PDCCH based on the first PDCCH monitoring and transmits at least one MSG3 when a PDCCH (e.g., PDCCH DCI) with an UL grant is received. If the WTRU determines not to perform the second (e.g., additional) PDCCH monitoring: The WTRU monitors for PDCCH based on the first PDCCH monitoring and transmits at least one MSG3 when a PDCCH (e.g., PDCCH DCI) with an UL grant is received.

[0171] Failure cases may trigger additional monitoring for blind MSG3 retransmission grant. In embodiments, the WTRU may begin a two-step RACH procedure (e.g. via transmission of MSGA) and subsequently start monitoring PDCCH for a response (e.g. subject to the MSGB response window). The WTRU may then receive, a random access response (RAR) instead of the expected MSGB, causing the WTRU to fall back to four-step Random Access. Upon reception of a RAR after a MSGA transmission, the WTRU may then transmit MSG3, and begin additional monitoring for a blind MSG3 retransmission grant.

[0172] In further embodiments, where failure cases which may trigger additional monitoring for blind MSG3 retransmission grant, the WTRU may transmit a random access preamble and begin monitoring for a response (e g. subject to the ra-response window) The WTRU may perform additional monitoring for a blind MSG3 retransmission grant, for example, if the WTRU did not receive a random access response (RAR) prior to the expiry of the ra-response window. In another example, the WTRU may perform additional monitoring if the WTRU did not receive a RAR within X ms of the expiry of the ra response window.

[0173] In further embodiments, where failure cases which may trigger additional monitoring for blind MSG3 retransmission grant, the WTRU may transmit one or more preamble(s) without receive a response from the network. The WTRU may perform additional monitoring for a blind MSG3 retransmission grant upon Y unsuccessful transmissions (e.g. a preamble transmission where the WTRU did not receive a response). Y may be indicated, for example, within system information, and RRC Release/Release with suspend message, or a HO command (e.g an RRC Reconfiguration with sync).

[0174] A WTRU may refrain from monitoring the PDCCH for grants for Msg3 retransmission, even if the network has implicitly or explicitly has indicated to it to monitor the PDCCH at certain occasions/durations. For example, the WTRU may stop monitoring the PDCCH at the indicated occasions/durations for getting the grants for Msg3 retransmissions on determining that it is in good coverage condition (E.g., serving cell’s signal level above a configured threshold)

[0175] A WTRU may refrain from monitoring the PDCCH for grants for Msg3 retransmission, wherein the WTRU may be configured to monitor PDCCH for getting the grants for Msg3 retransmissions at t1 , t2 and t3 (e g., all within the WTRU -gNB RTT time). The WTRU may monitor the PDCCH at t1 , gets the grant and perform the retransmission. However, at that time, the WTRU may detect that the network conditions have improved a lot and it is likely that no more blind retransmission are desirable for message 3. As such, the WTRU may not monitor the PDCCH at t2 and t3. In one example, the WTRU may skip additional PDCCH monitoring occasions if a DCI or PDCCH were not received in a given PDCCH monitoring occasion addressed to the WTRU’s computed RA-RNTI or T-CRNTI.

[0176] A WTRU may refrain from monitoring the PDCCH for grants for Msg3 retransmission, wherein the WTRU may send an indication to the network that it is not monitoring the PDCCH as previously configured. This indication could, for example, be included in one of the last repetition of Msg3 where the WTRU has determined no more repetition is desirable/needed. As another example, the indication could be a separate indication (E.g., a UCI multiplexed on PUSCH).

[0177] A WTRU may refrain from monitoring the PDCCH for grants for Msg3 retransmission, wherein the WTRU may override or skip configured additional PDCCH monitoring occasions for Msg3 retransmission if any of the conditions described above is satisfied or not met

[0178] A WTRU may refrain from monitoring the PDCCH for grants for Msg3 retransmission, wherein the WTRU may receive a grant in msg2 or msgB with a plurality of temporary C-RNTIs associated for the RA-RNTI corresponding to the transmitted RO and preamble. The WTRU may select one temporary C-RNTI and transmit Msg3 with such TC-RNTI if one condition (e.g. from the conditions described in 4 6) is satisfied, while the WTRU may transmit Msg3 with a different signaled TC-RNTI if the condition is not met or another condition is met. For example, the WTRU may receive a grant in RAR with 2 temporary C-RNTIs, whereby the WTRU transmits Msg3 with the first signaled temporary C-RNTI if measured RSRP is above a threshold or transmits Msg3 with the second signaled temporary C-RNTI if the measured RSRP is less than the threshold. The WTRU may determine the second temporary C-RNTI implicitly by adding an offset to a signaled first temporary C-RNTI part of the RAR or msgB. The WTRU may scramble the Msg3 PUSCH transmission with a sequence corresponding to the first TC-RNTI if the first TC-RNTI is selected, and the WTRU may scramble the Msg3 PUSCH transmission with a sequence corresponding to a second TC-RNTI if a second TC-RNTI is selected.

[0179] A WTRU may refrain from monitoring the PDCCH for grants for Msg3 retransmission, wherein the WTRU may be predefined or configured such that the WTRU may skip additional monitoring occasions for Msg3 retransmission if the WTRU transmits Msg3 using the second temporary C-RNTI. The WTRU may be configured or predefined such that the WTRU monitors additional PDCCH occasions for Msg3 retransmission if the first temporary C-RNTI was selected for the initial Msg3 transmission. The WTRU may monitor for Msg3 retransmission DCIs scheduled using any of the signaled temporary RNTIs in RAR, or (optionally in addition to) the temporary RNTI selected for the initial Msg3 transmission.

[0180] A WTRU may refrain from monitoring the PDCCH for grants for Msg3 retransmission, wherein the WTRU may be configured with a plurality of physical layer transmission Msg3 PUSCH parameters (e.g. transmit power, PSUCH scrambling sequence) where a first set of PHY transmission parameters is applied for Msg3 transmission if a condition is met, while a second set of PHY transmission parameter(s) is used if the condition is not met (or a different condition is met). For example, the WTRU may configure or predefined with two sequences to scramble the Msg3 PUSCH, whereby the WTRU transmits Msg3 PUSCH scrambled by a first sequence if the measured RSRP is less than a threshold, while the WTRU transmits Msg3 PUSCH scrambled by a second sequence if the measured RSRP is more than the threshold.

[0181] A WTRU may refrain from monitoring the PDCCH for grants for Msg3 retransmission, wherein the WTRU may receive more than one grant in msg2 or msgB, whereby one grant may be used if one condition is met and another grant is met if another condition is not met. Conditions may include at least one condition as described herein above. A subset of grant may be used for Msg3 retransmission(s)/repetition. Grants may be for the same HARQ process (e.g. HARQ PID 0) or different PIDs.

[0182] A WTRU may refrain from monitoring the PDCCH for grants for Msg3 retransmission, wherein the WTRU may receive a plurality of grants from the network whereby the WTRU transmits on the first grant if a condition (e.g RSRP above a threshold) is met and the WTRU discards the other grant(s). The WTRU may use a second grant or grants signaled for Msg3 repetition if a condition is met. For example, the WTRU may receive more than one grant, whereby the WTRU may select first grant if the WTRU measures RSRP (e.g SS- RSRP) above a threshold, and the WTRU may select secondary grant(s) (e.g. grants signaled for Msg3 retransmission) if the condition is not satisfied (e.g. RSRP less than a threshold). The WTRU may discard unused or not selected secondary grants.

[0183] A WTRU may refrain from monitoring the PDCCH for grants for Msg3 retransmission, wherein the WTRU may select a grant using a first HARQ process (e.g. HARQ process 0) for Msg3 transmission if a condition is met (e g. RSRP above a threshold) or a second HARQ process if the condition is not met.

[0184] A WTRU may continue monitoring for PDCCH based on the ra-ReponseWindow regardless of whether a RAR has been received. FIG. 11 shows an example where after an RA Preamble transmission 1110, RAR is received 1114, and there is a significant unused duration 1116 of the response window 1112. 1116. As shown in FIG. 12, the WTRU may continue to monitor PDCCH for a blind Msg3 retransmission grant 1118 after successfully receiving RAR 1114. Whether the WTRU may continue to monitor may be conditional on the time remaining in the RAR window. For example, the WTRU may use this embodiment only if greater than X ms remains in the ra-ReponseWindow duration, which may be a better option for an additional scheduling opportunity. In a further embodiment, the WTRU will use this solution only if less than X ms remains in the ra- ReponseWindow duration, which may be a better option for additional power saving

[0185] In a further embodiment, as shown in FIG. 13, the WTRU may start the ra- ContentionResolutionTimer 1318 immediately after Initial Msg3 transmission 1316 to monitor for additional blind MSG3 retransmission grant. In this case, a WTRU operating in a non-terrestrial network may start the ra- ContentionResolutionTimer in the first symbol after the end of initial Msg3 transmission 1316 to monitor for a blind Msg3 retransmission grant. In another example, the WTRU may start the ra-ContentionResolutionTimer 1322 at some offset 1320 from the end of initial MSG3 transmission The WTRU may then start the ra- Contention Resolution timer 1322 a second time after the WTRU-gNB RTT 1320. The WTRU may ignore expiry of the ra-ContentionResolutionTimer used for blind Msg3 retransmission grant reception when considering whether a MSG3 transmission was successful or not.

[0186] In embodiments, the WTRU may maintain an additional Msg3 re-TX timer, which the WTRU may start or resume at the start of each additional PDCCH monitoring occasion. The WTRU may monitor PDCCH (e g. for the reception of Msg3 re-TX grants) while such timer is running. The WTRU may (re)-start the timer upon (re)-transmitting Msg3 The WTRU may pause or stop the timer outside of configured additional PDCCH monitoring occasions for Msg3 re-TX [0187] Upon expiry of the time period, the WTRU may refrain from or skip monitoring addition PDCCH monitoring occasions for Msg3 re-TX. The WTRU may (re)-start or stop a timer upon reception of a retransmission grant for Msg3 retransmission. The WTRU may (re)-start the timer upon determining a HARQ NACK for the Msg3 payload. The WTRU may stop the timer upon reception of Msg4 or a determining HARQ- ACK as ACK for the Msg3 payload or the msgA payload. The WTRU may run such timer only if ra- responsewindow, msgB-responsewindow, and/or contention resolution timer are not running.

[0188] A WTRU may be configured (e.g part of broadcast SIB signaling) with whether the WTRU should monitor additional PDCCH occasions for scheduling Msg3 retransmission, configuration of additional PDCCH occasions for scheduling Msg3 retransmission pattern (herein referred to as the “Msg3 re-TX DRX pattern”), applicable PRACH resources, and/or a timer associated with additional PDCCH monitoring for Msg3 re-TX A “Msg3 re-TX DRX pattern” configuration indicates at least one of the following: a number of additional PDCCH occasions to monitor (e.g. after an initial Msg3 transmission and/or prior to the start of the contention resolution timer start), a start offset for PDCCH occasions(s) -e.g. an offset from the PRACH resource-, a periodicity between occasions, and/or one or more conditions of applicability of such pattern, such as those listed in herein above, and whether to monitor additional occasions if scheduling is received on a given occasion within the pattern. The WTRU may monitor additional PDCCH monitoring occasions for Msg3 re-TX if at least one condition listed herein above is satisfied or not met.

[0189] A WTRU may monitor additional PDCCH monitoring occasions for Msg3 re-TX during configured paging occasions and/or paging PDCCH monitoring occasions of one or more paging occasions. The WTRU may be configured, e.g. part of broadcast signaling, with a subset of paging PDCCH monitoring occasions and/or PCs to monitor for the reception of Msg3 or msgA retransmission grants. The WTRU may implicitly determine a subset of PCs or PDCCh monitoring occasions within a PC to monitor for the reception of Msg3 re-TX. For example, the WTRU may monitor one or more PO/paging monitoring occasions as a function of the PACH occasion selected for msg1 transmission and/or as function of the timing of the transmission occasion of the last Msg3 repetition For example, if Msg3 is transmitted attO, the WTRU may monitor PC and/or PDCCH paging monitoring occasions starting t1 + St where St is preconfigured, predefined, or determined implicitly by the WTRU as the gNB- WTRU RTT or a multiple of it. In another example, if msg1 is transmitted on a RO at tO, and possibly depending on whether an indication of extended coverage was selected from an associated preamble partition, the WTRU may monitor PC and/or PDCCH paging monitoring occasions starting tO + St where St is preconfigured, predefined, or determined implicitly by the WTRU as a function of the gNB-WTRU RTT

[0190] A PDCCH monitoring occasion for Msg3 retransmission may be applied as an additional PDCCH monitoring occasion for msgB, msgA retransmission, or Msg3 retransmission after fallback to four-step RA). The terms may be used interchangeably.

[0191] Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magnetooptical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, WTRU, terminal, base station, RNC, or any host computer.

Claims

CLAIMS What is Claimed:

1. A method implemented in a wireless transmit receive unit (WTRU) for determining additional monitoring occasions for a physical downlink control channel (PDCCH) transmission comprising: receiving first configuration information for performing a first monitoring for a first PDCCH transmission for a first Msg3 re-transmission; receiving second configuration information for performing a second monitoring for a second PDCCH transmission for a second Msg3 re-transmission; transmitting a physical random access channel (PRACH) preamble; starting a monitoring window and monitoring for a PDCCH transmission for a random access response (RAR); receiving an RAR and stopping the monitoring window; transmitting at least one Msg3 based on the received RAR; monitoring for a PDCCH transmission based on the second monitoring for a PDCCH transmission for the second Msg3 re-transmission; receiving a PDCCH transmission based on the second monitoring for the second PDCCH transmission; and re-transmitting a third Msg3 based on a grant received in the PDCCH transmission.

2. The method of claim 1 , wherein the second configuration information includes an explicit indication to perform the second monitoring for the PDCCH transmission for the second Msg3 re-transmission.

3. The method of claim 2, wherein the explicit indication is received via an RAR; a PDCCH order, or system information block (SIB) signaling.

4. The method of any of claims 1 to 3, wherein a validity time is associated with the explicit indication indicating a time period for which the explicit indication is valid.

5. The method of any of claims 2 to 4, wherein a validity area is associated with the explicit indication indicating an area in which the explicit indication is valid.

6. The method of any of claims 2 to 5, wherein the explicit indication includes time period information for when grants for Msg3 re-transmission are expected to be received.

7. The method of any of claims 1 to 6, further comprising monitoring for a PDCCH transmission based on the first monitoring for the first PDCCH transmission after the second monitoring for the second PDCCH transmission, and transmitting a fourth Msg3 when a second PDCCH transmission is received.

8. The method of any of claims 1 to 7 wherein the conditions to perform the second monitoring for PDCCH transmission for blind Msg3 re-transmission, are based on one or more values;

9. The method of claim 8, wherein the values include at least one of a WTRU distance from a cell center, angle of a satellite relative to earth, or RSRP.

10. The method of claims 8 or 9, wherein the values are provided in system information, a handover (HO) command, radio resource control (RRC) release message, or RAR.

11. A method implemented in a wireless transmit receive unit (WTRU) for determining additional occasions for monitoring for a physical downlink control channel (PDCCH) transmission comprising: receiving first configuration information for performing a first monitoring for a first PDCCH transmission for a first Msg3 retransmission; receiving second configuration information for performing a second monitoring for a second PDCCH transmission for a second Msg3 re-transmission; starting a response window and monitoring for a PDCCH transmission for a Random Access Response; receiving a Random Access Response and stopping the response window; transmitting at least one Msg3 based on the received Random Access Response; determining based on an Msg3 repetition characteristic or an override condition whether to perform the second monitoring for a second PDCCH transmission for re-transmission; and monitoring for second PDCCH transmission for the second Msg3 re-transmission grant in response to the Msg3 repetition characteristic being met or the override condition not being satisfied.

12. The method of claim 11 , wherein a third configuration information is provided via radio resource control (RRC) signaling, a random access message, medium access control control element (MAC CE), paging message or downlink control information (DCI), the third configuration information indicating whether the WTRU performs the additional monitoring for blind Msg3 transmission grant based on Msg3 characteristics.

13. The method of claim 11 or 12, wherein the override condition is received via random access response (RAR), message B (MSGB) or system information.

14. The method of any of claims 11 to 13, wherein the second monitoring for PDCCH transmission is not performed regardless of Msg3 characteristics if the override condition is met.

15. The method of any of claims 11 to 14, wherein whether the WTRU performs the second monitoring or additional monitoring is a function of a predetermined number of Msg3 re-transmissions.

16. A wireless transmit receive unit (WTRU) configured to: receive first configuration information for performing a first monitoring for a first physical downlink control channel (PDCCH transmission) for a first Msg3 re-transmission; receive second configuration information for performing a second monitoring for a second PDCCH transmission for a second Msg3 re-transmission; transmit a physical random access channel (PRACH) preamble; start a monitoring window and monitor for a PDCCH transmission for a random access response (RAR); receive an RAR and stop the monitoring window; transmit at least one Msg3 based on the received RAR; monitor for a PDCCH transmission based on the second monitoring for a PDCCH transmission for the second Msg3 re-transmission; receive a PDCCH transmission based on the second monitoring for the second PDCCH transmission; and re-transmit a third Msg3 based on a grant received in the PDCCH transmission.

17. The WTRU of claim 16, wherein the second configuration information includes an explicit indication to perform the second monitoring for the PDCCH transmission for the second Msg3 re-transmission.

18. The WTRU of claim 17, wherein the explicit indication is received via an RAR; a PDCCH order or system information block (SIB) signaling.

19. The WTRU of any of claims 16 to 18, wherein a validity time is associated with the explicit indication indicating a time period for which the explicit indication is valid.

20. The WTRU of any of claims 16 to 19, wherein a validity area is associated with the explicit indication indicating an area in which the explicit indication is valid.