CN121002995A - A method for blind retransmission in non-terrestrial networks implemented in WTRU - Google Patents

Abstract

Methods implemented in a Wireless Transmit Receive Unit (WTRU) are described for determining additional PDCCH monitoring occasions to check for authorization for blind Msg3 retransmission based on receiving an explicit indication to perform second PDCCH monitoring, msg3 characteristics, override conditions, or satisfaction of one or more conditions.

Description

Method implemented in a WTRU for blind retransmission in a non-terrestrial network

Cross Reference to Related Applications

The application claims the benefit of U.S. provisional application No. 63/445609 filed on day 14, 2, 2023, the contents of which are incorporated herein by reference.

Background

In the terrestrial network (TERRESTRIAL NETWORK), the gap between the MAC entity stop ra-ResponseWindow and start ra-ContentionResolutionTimer is typically short enough to allow near continuous monitoring of the PDCCH. The start of the offset ra-ContentionResolutionTimer in the non-terrestrial network (NTN) significantly increases this gap, limiting the ability to quickly receive blind Msg3 retransmission grants after the ra-ResponseWindow stops.

The additional delay means that the network may not schedule blind MSG3 retransmissions until at least the WTRU-gNB Round Trip Time (RTT), thereby limiting scheduler flexibility and increasing the latency of the RA procedure. Furthermore, MSG3 repetition may not always be a suitable solution in NTN given RACH congestion caused by a large number of WTRUs performing RACH simultaneously, which may impose limitations on the resources required to perform multiple consecutive repetitions. The WTRU may always continuously monitor PDCCH between RA windows, however blind retransmission grants are opportunistic and the network may always choose not to provide one. This may result in additional and unnecessary WTRU power consumption, considering that the WTRU-gNB RTT may be quite long.

Thus, it may be desirable to enable blind retransmission grant reception in less than WTRU-gNB RTT after initial MSG3 retransmission in a non-terrestrial network without requiring the WTRU to continuously monitor PDCCH.

Disclosure of Invention

In an embodiment, a method for determining additional monitoring occasions for Physical Downlink Control Channel (PDCCH) transmissions may be implemented in a Wireless Transmit Receive Unit (WTRU). The method may include receiving first configuration information for performing first monitoring of a first PDCCH transmission for a first Msg3 retransmission, receiving second configuration information for performing second monitoring of a second PDCCH transmission for a second Msg3 retransmission, transmitting a Physical Random Access Channel (PRACH) preamble, starting a monitoring window and monitoring PDCCH transmissions of 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 PDCCH transmissions based on the second monitoring of PDCCH transmissions for the second Msg3 retransmission, receiving PDCCH transmissions based on the second monitoring of the second PDCCH transmissions, and retransmitting a third Msg3 based on grants received in the PDCCH transmissions. In further embodiments, the method may include wherein the second configuration information includes an explicit indication to perform a second monitoring of PDCCH transmissions for a second Msg3 retransmission. In further embodiments, the method may include wherein the explicit indication is received via a random access response, a PDCCH command, or SIB signaling. In further embodiments, the method may include wherein the validity time is associated with an explicit indication indicating a period of time for which the explicit indication is valid. In further embodiments, the method may include wherein the validity region is associated with an explicit indication indicating the region in which the explicit indication is valid. In further embodiments, the method may include wherein the explicit indication includes time period information of when an grant for an Msg3 retransmission is expected to be received. In further embodiments, the method may include monitoring a PDCCH transmission based on the first monitoring of the first PDCCH transmission after the second monitoring of the second PDCCH transmission, and transmitting a fourth Msg3 when the second PDCCH transmission is received. In further embodiments, the condition to perform the second monitoring of PDCCH transmissions for blind Msg3 retransmissions is based on one or more values. In further embodiments, the value may include at least one of WTRU distance from the cell center, angle of satellite with respect to earth, or RSRP. In further embodiments, the method may include providing the values in system information, a handover command, an RRC release message, or a RAR.

In further embodiments, a method may be implemented in a WTRU for determining additional occasions for monitoring PDCCH transmission occasions, the method may include receiving first configuration information for performing first monitoring of a first PDCCH transmission for a first Msg3 retransmission, receiving second configuration information for performing second monitoring of a second PDCCH transmission for a second Msg3 retransmission, starting a response window and monitoring the PDCCH transmission for an RAR, receiving the RAR and stopping the response window, transmitting at least one Msg3 based on the received RAR, determining whether to perform the second monitoring of the second PDCCH transmission for the retransmission based on an Msg3 repetition characteristic or override (override) condition, and monitoring a second PDCCH transmission for a second Msg3 retransmission grant in response to the Msg3 repetition characteristic being met or the override condition not being met. In further embodiments, the method may include wherein the third configuration information is provided via Radio Resource Control (RRC) signaling, random access messages, medium access control elements (MAC CEs), paging messages, or Downlink Control Information (DCIs), the third configuration information indicating whether the WTRU performs additional monitoring of the blind Msg3 transmission grant based on the Msg3 characteristics. In further embodiments, a method may include wherein the override condition is received via a Random Access Response (RAR), message B (MSGB), or system information. In further embodiments, the method may include wherein if the override condition is met, the second monitoring of the PDCCH transmission is not performed regardless of the Msg3 characteristic. In further embodiments, the method may include wherein the WTRU performs a second monitoring or additional monitoring is a function of a predetermined number of Msg3 retransmissions.

In further embodiments, the WTRU may be configured to perform any of the methods described above.

Drawings

A more detailed understanding can be obtained from the following description, given by way of example in conjunction with the accompanying drawings, wherein like reference numerals indicate like elements, and wherein:

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

Fig. 1B is a system diagram illustrating an example wireless transmit/receive unit (WTRU) that may be used within the communication system shown in fig. 1A, in accordance with an embodiment;

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 communication system shown in fig. 1A, according to an embodiment;

fig. 1D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communication system shown in fig. 1A, according to an embodiment;

fig. 2 is a messaging diagram of a four-step contention-based random access procedure;

fig. 3 is a messaging diagram of a two-step contention-based random access procedure;

FIG. 4 is a timing diagram of the blind retransmission grant reception by Msg3 in a terrestrial network;

FIG. 5 is a timing diagram of the blind retransmission grant reception by Msg3 in a non-terrestrial network;

FIG. 6 is an exemplary flow chart of additional PDCCH monitoring;

fig. 7 is an exemplary flow chart for triggering additional PDCCH monitoring based on explicit indications;

FIG. 8 is an exemplary flow chart for triggering additional PDCCH monitoring based on an Msg3 repetition characteristic;

fig. 9 is an exemplary flow chart for triggering additional PDCCH monitoring based on satisfaction of a condition;

fig. 10A is an exemplary flow chart for triggering additional PDCCH monitoring;

Fig. 10B is a further exemplary flowchart of triggering additional PDCCH monitoring;

FIG. 11 is a timing diagram of additional monitoring opportunities;

FIG. 12 is a timing diagram of additional monitoring opportunities, and

Fig. 13 is a timing chart of additional monitoring opportunities.

Detailed Description

Fig. 1A is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. Communication system 100 may be a multiple-access system that provides content, such as voice, data, video, messaging, broadcast, etc., to a plurality of wireless users. Communication system 100 may enable multiple wireless users to access such content by sharing system resources including wireless bandwidth. For example, communication system 100 may employ one or more channel access methods such as Code Division Multiple Access (CDMA), time Division Multiple Access (TDMA), frequency Division Multiple Access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero-tail unique word discrete fourier transform spread spectrum OFDM (ZT-UW-DFT-S-OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter Bank Multicarrier (FBMC), and the like.

As shown in fig. 1A, the communication system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a Radio Access Network (RAN) 104, a Core Network (CN) 106, a Public Switched Telephone Network (PSTN) 108, the internet 110, and other networks 112, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment. As an example, any of the WTRUs 102a, 102b, 102c, 102d may be referred to as a Station (STA), may be configured to transmit and/or receive wireless signals, and may include User Equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular telephones, personal Digital Assistants (PDAs), smartphones, laptop computers, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, internet of things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., tele-surgery), industrial devices and applications (e.g., robots and/or other wireless devices operating in an industrial and/or automated processing chain context), consumer electronics devices, devices operating on a commercial and/or industrial wireless network, and the like. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

Communication system 100 may also include base station 114a and/or 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 Base Transceiver Stations (BTSs), node bs, eNode bs (enbs), home node bs, home eNode bs, next generation node bs, such as gNode B (gNB), new Radio (NR) node bs, site controllers, access Points (APs), wireless routers, and the like. Although each of the base stations 114a, 114b is 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.

Base station 114a may be part of RAN 104 and RAN 104 may also include other base stations and/or network elements (not shown), such as Base Station Controllers (BSCs), radio Network Controllers (RNCs), relay nodes, and the like. Base station 114a and/or 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 a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage for wireless services to a particular geographic area that may be relatively fixed or may change over time. The cell may also be divided into cell sectors. For example, a cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, one for each sector of a cell. In an embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and may use multiple transceivers for each sector of a cell. For example, beamforming may be used to transmit and/or receive signals in desired spatial directions.

The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, and the air interface 116 may be any suitable wireless communication link (e.g., radio Frequency (RF), microwave, centimeter wave, millimeter wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable Radio Access Technology (RAT).

More specifically, as described above, communication 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, a base station 114a in the RAN 104 and WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) terrestrial radio access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 116.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).

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 use Long Term Evolution (LTE) and/or LTE-advanced (LTE-a) and/or LTE-advanced Pro (LTE-APro) to establish the air interface 116.

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 use NR to establish the air interface 116.

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, e.g., using a Dual Connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by transmissions sent to/from multiple types of base stations (e.g., enbs and gnbs) and/or multiple types of radio access technologies.

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, CDMA20001X, CDMA EV-DO, temporary standard 2000 (IS-2000), temporary standard 95 (IS-95), temporary standard 856 (IS-856), global system for mobile communication (GSM), enhanced data rates for GSM evolution (EDGE), GSM EDGE (GERAN), and the like.

The base station 114B in fig. 1A may be, for example, a wireless router, home node B, home eNode B, or access point, and may utilize any suitable RAT to facilitate wireless connectivity in local areas such as businesses, homes, vehicles, campuses, industrial facilities, air corridors (e.g., for use by drones), roads, 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 pico cell or femto cell. 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.

The RAN 104 may communicate with the CN 106, and the CN 106 may be any type of network configured to provide voice, data, application, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102 d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106 may provide call control, billing services, mobile location based services, prepaid calls, internet connectivity, video distribution, etc., and/or perform advanced security functions such as user authentication. Although not shown in fig. 1A, it should be appreciated that RAN 104 and/or CN 106 may communicate directly or indirectly with other RANs that employ the same RAT as RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104 that may utilize NR radio technology, the CN 106 may also communicate with another RAN (not shown) that employs GSM, UMTS, CDMA2000, wiMAX, E-UTRA, or WiFi radio technology.

The CN 106 may also act as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the internet 110, and/or other networks 112. PSTN 108 may include circuit-switched telephone networks that provide Plain Old Telephone Services (POTS). The internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as Transmission Control Protocol (TCP), user Datagram Protocol (UDP), and/or Internet Protocol (IP) in the TCP/IP internet protocol suite. Network 112 may include wired and/or wireless communication networks owned and/or operated by other service providers. For example, the network 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.

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

Fig. 1B is a system diagram illustrating an example WTRU 102. As shown in fig. 1B, WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit/receive element 122, a speaker/microphone 124, a keypad 126, a display/touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a Global Positioning System (GPS) chipset 136, and/or other peripheral devices 138. It should be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

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 conjunction 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. Processor 118 may be coupled to transceiver 120, and transceiver 120 may be coupled to transmit/receive element 122. Although fig. 1B depicts the processor 118 and the transceiver 120 as separate components, it should be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

The transmit/receive element 122 may be configured to transmit signals to and receive signals from a base station (e.g., base station 114 a) 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 transmission/reception element 122 may be an emitter/detector configured to transmit and/or receive, for example, IR, UV or visible light signals. In yet another embodiment, the transmit/receive element 122 may be configured to transmit and/or receive both RF signals and optical signals. It should be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals.

Although the transmit/receive element 122 is depicted as a single element in fig. 1B, 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.

The transceiver 120 may be configured to modulate signals to be transmitted by the transmit/receive element 122 and demodulate signals received by the transmit/receive element 122. As described 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, for example, NR and IEEE 802.11.

The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker/microphone 124, a keypad 126, and/or a display/touchpad 128, such as a Liquid Crystal Display (LCD) display unit or an Organic Light Emitting Diode (OLED) display unit. The processor 118 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128. In addition, the processor 118 may access information from and store data in any type of suitable memory, such as non-removable memory 130 and/or 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. 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, a memory that is not physically located on the WTRU 102, such as on a server or home computer (not shown).

The processor 118 may receive power from the power supply 134 and may be configured to distribute power and/or control power to 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 cells (e.g., nickel cadmium (NiCd), nickel zinc (NiZn), nickel metal hydride (NiMH), lithium ion (Li ion), etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to a GPS chipset 136, and the GPS chipset 136 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 information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114 b) over the air interface 116 and/or determine its location based on the timing of signals received from two or more nearby base stations. It should be appreciated that the WTRU 102 may obtain location information by any suitable location determination method while remaining consistent with an embodiment.

The processor 118 may also be coupled to other peripheral devices 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 number of the cells to be processed, peripheral devices 138 may include an accelerometer, an electronic compass, a camera, a satellite transceiver, digital camera (for photo and/or video), camera module Universal Serial Bus (USB) port, vibration device, television transceiver, hands-free headset,Modules, frequency Modulation (FM) radio units, digital music players, media players, video game player modules, internet browsers, virtual reality and/or augmented reality (VR/AR) devices, activity trackers, and the like. The peripheral device 138 may include one or more sensors. The sensor may be one or more of a gyroscope, accelerometer, hall effect sensor, magnetometer, orientation sensor, proximity sensor, temperature sensor, time sensor, geolocation sensor, altimeter, light sensor, touch sensor, magnetometer, barometer, gesture sensor, biometric sensor, humidity sensor, and the like.

WTRU 102 may include a full duplex radio for which transmission and reception of some or all signals (e.g., associated with a particular subframe for both 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 hardware (e.g., choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In embodiments, the WTRU 102 may include a half-duplex radio for which some or all of the signals (e.g., associated with a particular subframe for UL (e.g., for transmission) or DL (e.g., for reception) are transmitted and received.

Fig. 1C is a system diagram illustrating a RAN 104 and a CN 106 according to an embodiment. As described above, the RAN 104 may employ an E-UTRA radio technology to communicate with WTRUs 102a, 102b, 102c over an air interface 116. RAN 104 may also communicate with CN 106.

RAN 104 may include eNode-bs 160a, 160B, 160c, but it will be appreciated that RAN 104 may include any number of eNode-bs while remaining consistent with an embodiment. each of the eNode-bs 160a, 160B, 160c may include one or more transceivers for communicating with the WTRUs 102a, 102B, 102c over the air interface 116. In one embodiment, eNode-B160 a, 160B, 160c may implement MIMO technology. Thus, for example, eNode-B160 a may use multiple antennas to transmit wireless signals to WTRU 102a and/or to receive wireless signals from WTRU 102 a.

Each of 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, user scheduling in UL and/or DL, and the like. As shown in fig. 1C, eNode-bs 160a, 160B, 160C may communicate with each other over an X2 interface.

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. Although the foregoing elements are depicted as part of the CN 106, it should be appreciated that any of these elements may be owned and/or operated by entities other than the CN operator.

MME 162 may be connected to each of eNode-bs 162a, 162B, 162c in RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating the user of the WTRUs 102a, 102b, 102c, bearer activation/deactivation, selecting a particular serving gateway during initial attachment of the WTRUs 102a, 102b, 102c, and the like. MME 162 may provide control plane functionality for switching between RAN 104 and other RANs (not shown) employing other radio technologies, such as GSM and/or wideband CDMA.

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

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

The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to a circuit-switched network, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and legacy landline communication 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 other networks 112, which other networks 112 may include other wired and/or wireless networks owned and/or operated by other service providers.

Although the WTRU is depicted in fig. 1A-1D as a wireless terminal, it is contemplated that in some representative embodiments such a terminal may use (e.g., temporarily or permanently) a wired communication interface with a communication network.

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

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. An AP may have access or interface to a Distribution System (DS) or another type of wired/wireless network that carries traffic into and/or out of the BSS. Traffic originating outside the BSS to the STA may arrive through the AP and may be delivered to the STA. Traffic originating from the STA to a destination outside the BSS may be sent to the AP to be delivered to the corresponding destination. Traffic between STAs within the BSS may be transmitted by the AP, e.g., where the source STA may transmit traffic to the AP and the AP may deliver the traffic to the destination STA. Traffic between STAs within a BSS may be considered and/or referred to as peer-to-peer traffic. Peer traffic may be sent between a source STA and a destination STA (e.g., directly between the source STA and the destination STA) using Direct Link Setup (DLS). In certain representative embodiments, DLS may use 802.11e DLS or 802.11z Tunneling DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and STAs (e.g., all STAs) within or using the IBSS may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad-hoc" communication mode.

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

High Throughput (HT) STAs may communicate using 40MHz wide channels, e.g., forming 40MHz wide channels via a combination of a primary 20MHz channel and an adjacent or non-adjacent 20MHz channel.

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

The sub-1 GHz mode of operation is supported by 802.11af and 802.11 ah. The channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah relative to the channel operating bandwidths and carriers used in 802.11n and 802.11 ac. The 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the TV white space (TVWS) spectrum, and the 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to representative embodiments, 802.11ah may support meter type control/Machine Type Communication (MTC), such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, e.g., limited capabilities, including supporting (e.g., supporting only) certain and/or limited bandwidths. MTC devices may include batteries with battery lives above a threshold (e.g., to maintain very long battery lives).

WLAN systems that can support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include channels that can be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and/or limited by the STA supporting the minimum bandwidth operation mode among all STAs operating in the BSS. In the example of 802.11ah, for STAs (e.g., MTC-type devices) that support (e.g., only) 1MHz mode, the primary channel may be 1MHz wide, even though the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and/or other channel bandwidth modes of operation. Carrier sensing and/or Network Allocation Vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because the STA (which only supports the 1MHz mode of operation) is transmitting to the AP, all available frequency bands may be considered busy even if most available frequency bands remain idle.

In the united states, the available frequency band that can be used by 802.11ah is from 902MHz to 928MHz. In korea, the available frequency band is from 917.5MHz to 923.5MHz. In Japan, the available frequency band is from 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

Fig. 1D is a system diagram illustrating a RAN 104 and a CN 106 according to an embodiment. As described above, the RAN 104 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. RAN 104 may also communicate with CN 106.

RAN 104 may include gnbs 180a, 180b, 180c, but it should be understood that RAN 104 may include any number of gnbs while remaining consistent with embodiments. Each of the gnbs 180a, 180b, 180c may include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, gnbs 180a, 180b, 180c may implement MIMO technology. For example, gnbs 180a, 108b may utilize beamforming to transmit signals to gnbs 180a, 180b, 180c and/or to receive signals from gnbs 180a, 180b, 180 c. Thus, the gNB 180a may use multiple antennas to transmit wireless signals to the WTRU 102a and/or receive wireless signals from the WTRU 102a, for example. In an embodiment, the gnbs 180a, 180b, 180c may implement carrier aggregation techniques. 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 the unlicensed spectrum while the remaining component carriers may be on the licensed spectrum. In an embodiment, the gnbs 180a, 180b, 180c may implement coordinated multipoint (CoMP) techniques. For example, WTRU 102a may receive cooperative transmissions from gNB 180a and gNB 180b (and/or gNB 180 c).

The WTRUs 102a, 102b, 102c may communicate with the gnbs 180a, 180b, 180c using transmissions associated with the scalable digital theory (numerology). For example, the OFDM symbol interval and/or OFDM subcarrier interval may vary for different transmissions, different cells, and/or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gnbs 180a, 180b, 180c using subframes or Transmission Time Intervals (TTIs) of various or scalable lengths (e.g., including different numbers of OFDM symbols and/or absolute times lasting different lengths).

The gnbs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in an independent configuration and/or in a non-independent configuration. In a stand-alone configuration, the WTRUs 102a, 102B, 102c may communicate with the gnbs 180a, 180B, 180c without also accessing other RANs (e.g., such as eNode-bs 160a, 160B, 160 c). In an independent configuration, the WTRUs 102a, 102b, 102c may utilize one or more of the gnbs 180a, 180b, 180c as mobility anchors. In a stand-alone configuration, the WTRUs 102a, 102b, 102c may use signals in unlicensed frequency bands to communicate with the gnbs 180a, 180b, 180 c. In a non-standalone configuration, the WTRUs 102a, 102B, 102c may communicate/connect with the gnbs 180a, 180B, 180c to the gnbs 180a, 180B, 180c while also communicating/connecting with another RAN, such as the eNode-bs 160a, 160B, 160 c. For example, the 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 a non-standalone configuration, the eNode-bs 160a, 160B, 160c may serve as mobility anchors for the WTRUs 102a, 102B, 102c, and the gnbs 180a, 180B, 180c may provide additional coverage and/or throughput for serving the WTRUs 102a, 102B, 102 c.

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 UL and/or DL, support of network slices, interworking between DC, NR, and E-UTRA, routing of user plane data towards User Plane Functions (UPFs) 184a, 184b, routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, and the like. As shown in fig. 1D, gnbs 180a, 180b, 180c may communicate with each other through an Xn interface.

The CN 106 shown in fig. 1D 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. Although the foregoing elements are depicted as part of the CN 106, it should be appreciated that any of these elements may be owned and/or operated by entities other than the CN operator.

The AMFs 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 function as control nodes. For example, the AMFs 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling different Protocol Data Unit (PDU) sessions with different requirements), selecting a particular SMF 183a, 183b, managing registration areas, terminating non-access stratum (NAS) signaling, mobility management, and the like. The AMFs 182a, 182b may use network slices to customize CN support for the WTRUs 102a, 102b, 102c based on the type of service the WTRUs 102a, 102b, 102c are using. 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 large-scale mobile broadband (eMBB) access, services for MTC access, and the like. The AMFs 182a, 182b may provide control plane functionality for switching between the RAN 104 and other RANs (not shown) employing other radio technologies, such as LTE, LTE-A, LTE-a Pro, and/or non-3 GPP access technologies, such as WiFi.

The SMFs 183a, 183b may be connected to AMFs 182a, 182b in the CN 106 via an N11 interface. The SMFs 183a, 183b may also be connected to UPFs 184a, 184b in the CN 106 via an N4 interface. SMFs 183a, 183b may select and control UPFs 184a, 184b and configure the routing of traffic through UPFs 184a, 184b. The SMFs 183a, 183b may perform other functions such as managing and assigning WTRU IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing DL data notifications, and the like. The PDU session type may be IP-based, non-IP-based, ethernet-based, and the like.

The UPFs 184a, 184b may be connected to one or more of the gnbs 180a, 180b, 180c in the RAN 104 via an N3 interface that may provide the WTRUs 102a, 102b, 102c with access to a packet-switched network, such as the internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. UPFs 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.

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 other networks 112, which other networks 112 may include other wired and/or wireless networks owned and/or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may connect to the local DNs 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

In view of the fig. 1A-1D and the corresponding description of fig. 1A-1D, one or more or all of the functions described with respect to one or more of the WTRUs 102a-D, the base stations 114a-B, the eNode-bs 160a-c, the MMEs 162, the SGWs 164, the PGWs 166, the gnbs 180a-c, the AMFs 182a-B, the UPFs 184a-B, the SMFs 183a-B, the DNs 185a-B, and/or any other device(s) described herein may be performed by one or more emulating devices (not shown). The emulation device may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation device may be used to test other devices and/or analog network and/or WTRU functions.

The simulated device may be designed to enable one or more tests of other devices in a laboratory environment and/or in an operator network environment. For example, one or more emulated devices may perform one or more or all functions while being implemented and/or deployed, in whole or in part, as part of a wired and/or wireless communication network in order to test other devices within the communication network. One or more emulation devices can perform one or more or all of the functions while being temporarily implemented/deployed as part of a wired and/or wireless communication network. The emulation device can be directly coupled to another device for the purpose of testing and/or performing testing using over-the-air wireless communications.

One or more emulation devices can perform one or more (including all) functions while not being implemented/deployed as part of a wired and/or wireless communication network. For example, the simulation device may be used to test a test scenario in a laboratory and/or a non-deployed (e.g., test) wired and/or wireless communication network in order to enable testing of one or more components. The one or more simulation devices may be test devices. The emulating device can transmit and/or receive data using direct RF coupling and/or wireless communication via RF circuitry (e.g., which can include one or more antennas). Acronyms and abbreviations 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 classes

CCA clear channel assessment

CCE control channel element

CE control element

CG configured grant or cell group

CP cyclic prefix

CP-OFDM conventional OFDM (depending on the 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 allocation index

DCI downlink control information

DFI downlink feedback information

DG dynamic authorization

DL downlink

DM-RS demodulation reference signal

DRB data radio bearer

ELAA enhanced license assisted access

FeLAA further enhanced license assisted access

GEO geostationary orbit

HARQ hybrid automatic repeat request

LAA admission assisted access

LBT listen before talk

LEO low earth orbit

LTE is, for example, from long term evolution of 3GPP LTE R8 and above

NACK negative ACK

MCS modulation and coding scheme

MIMO multiple input multiple output

NR new radio

NTN non-ground 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

Central unit of RCU radio access network

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 Handover gap (in self contained subframe)

SPS semi-persistent scheduling

SUL supplemental uplink

TB transport block

TBS transport block size

TC-RNTI temporary C-RNTI

TRP transmission/reception point

TSC time sensitive communication

TSN time sensitive networking

UL uplink

URLLC ultra-reliable and low-latency communications

WBWP wide bandwidth portion

WLAN wireless local area networks and related technologies ((IEEE 802. Xx) domain)

Terms further defined herein may be referred to using a variety of different symbols. Hereinafter, the 'a' and 'an' and the like phrases may be construed as 'one or more' and 'at least one'. Similarly, any term ending with the suffix '(s)' may be interpreted as 'one or more' and 'at least one'. The term "may" will be interpreted as, for example, "may".

The random access may be performed in a contention-based manner, i.e., contention-based random access (CBRA) and contention-free (i.e., contention-free random access (CFRA)), supporting two types of random access in the NR-four-step RA and two-step RA. two-step RACH procedures are useful in latency-critical scenarios because the signaling exchanges required to complete the random access procedure are reduced.

Four-step and two-step processes are described herein with reference to fig. 2 and 3, respectively.

The four-step random access procedure may be implemented as follows and as shown in fig. 2. At 210, a four-step random access begins with the WTRU transmitting MSG1, MSG1 containing a preamble on the PRACH. At the time of MSG1 transmission, the WTRU monitors random access response (e.g., RAR/MSG 2) from the network within a configured window. Upon receiving the RAR containing the UL grant and the timing advance command, at 212, the WTRU applies the timing advance command and sends Msg3 using the UL grant provided in the RAR, at 214. Upon Msg3 transmission, the WTRU again monitors the network response (e.g., msg 4), which contains contention resolution information. If the contention resolution is successful at 216, the random access is complete and the WTRU begins to connect. If contention resolution fails, the WTRU resumes random access via the transmission of Msg1, i.e., repeats 210.

The two-step random access procedure may be implemented as follows and as shown in fig. 3. The two-step random access starts with a transmission MsgA, msgA comprising a preamble 310 on PRACH and a payload 312 on PUSCH. After MsgA transmission, the WTRU monitors for a response from the network (e.g., msgB) within a configuration window containing information about contention resolution. At 314, if contention resolution is successful, the WTRU terminates the random access procedure. If contention resolution fails and a back-off indication is provided in MsgB, the WTRU may perform Msg3 transmission using the UL grant contained within the MsgB back-off indication and begin monitoring for contention resolution. If contention resolution fails again after the Msg3 transmission, the WTRU reverts to MsgA transmissions. If MsgA transmission fails the configured number of times, the WTRU may revert to four-step random access.

When initiating a random access procedure based on a network configuration, which type of random access is used is selected (two or four steps). When contention-free random access resources are configured, the WTRU performs four or two steps of random access depending on whether the random access resources correspond to two or four steps. If no contention-free random access resources are provided, the WTRU selects between four and two steps of random access based on an RSRP threshold.

At random access preamble transmission, the MAC entity will start ra-ResponseWindow at the PDCCH occasion. The WTRU may monitor the PDCCH while ra-ResponseWindow is running. Upon successful RAR reception containing a random access PREAMBLE identifier matching the transmitted preamble_index, the MAC entity may stop ra-ResponseWindow and thus monitor the random access response(s).

As shown in fig. 4, after RA preamble transmission 410, RA-ResponseWindow412 and RAR 414 or blind Msg3 retransmission grant 422, at Msg3 (re) transmission 418, 426, the MAC entity will start RA-ContentionResolutionTimer 420, 428 in the first symbol after the end of Msg3 (re) transmission 418, 426. The WTRU may monitor the PDCCH while ra-ContentionResolutionTimer is running (420, 428). The MAC entity will stop ra-ContentionResolutionTimer if a reception notification of the PDCCH transmission is received from the lower layer and the PDCCH transmission is addressed to the C-RNTI or TEMPORARY _c-RNTI 430. The processing time between the reception of RAR or blind Ms3 retransmission grants is shown as 416, 424 in fig. 4.

To improve NR uplink coverage for both FR1 and FR2, several enhancements of MSG3PUSCH may be supported. These include MSG3 repetition, where aggregation of multiple timeslots with TB repetition for MSG3 transmission can 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 resources and request blind MSG3 retransmission when the RSRP of the DL path loss reference is below a configured threshold, wherein the network may send a separate grant to retransmit the MSG3 prior to the decoding result of the initial transmission.

WTRU-gNB RTT calculation and pre-backoff in non-terrestrial networks may be implemented as follows. Due to the height and beam diameter of the NTN platform, the Round Trip Time (RTT) and the maximum differential delay are significantly greater than those of the terrestrial system. In a typical NTN deployment, RTT can range from 25.77ms (leo@600 km height) to 541.46ms (GEO), and the maximum differential delay ranges from 3.12ms to 10.3ms. To minimize impact on existing NR systems (e.g., to avoid preamble ambiguity or to properly time the receive window), the WTRU may perform timing precompensation prior to initial access. The timing precompensation procedure requires the WTRU to obtain its position via GNSS and feeder link (or common) delays and satellite positions via satellite ephemeris data. Satellite ephemeris data is periodically broadcast in the system information and contains satellite velocity, direction and speed. The WTRU may then estimate the distance (and thus delay) from the satellite and then add the feeder link delay component to obtain a full WTRU-gNB RTT, which is then used to offset the timer, receive window, or timing relationship.

The adaptation of PDCCH monitoring for non-terrestrial networks may be implemented as follows. PDCCH monitoring during random access may modify non-terrestrial networks by offsetting the start of ra-ResponseWindow, msgB-ResponseWindow and ra-ContentionResolutionTimer by WTRU-gNB RTT. This may ensure that ra-ResponseWindow and ra-ContentionResolutionTimer do not expire prematurely due to the long propagation delay characteristics of non-terrestrial networks.

Adaptation of MSG3 coverage enhancement to non-terrestrial networks may be achieved as follows. For NTN, two Msg3 coverage enhancement techniques may be supported. For example, type a PUSCH repetition is supported by starting ra-ContentionResolutionTimer in the first symbol after the end of all repetitions of Msg3 transmission plus WTRU-gNB RTT. If a PDCCH addressed to a TC-RNTI indicating a UL grant for Msg3 retransmission is received after the start of ra-ContentionResolutionTimer, blind Msg3 retransmission is supported by ignoring the expiration of ra-ContentionResolutionTimer.

As shown in fig. 4, in a terrestrial network, the gap 416 between the MAC entity stop 414ra-ResponseWindow412 and start ra-ContentionResolutionTimer420 is typically very short, allowing near continuous monitoring of the PDCCH. Fig. 5 shows that the start 520 of ra-ContentionResolutionTimer 522 is shifted in NTN such that the gap including the processing time 514 and the additional time 518 increases significantly, limiting the ability to quickly receive blind Msg3 retransmission grants after the ra-ResponseWindow 510 stops 512.

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

The WTRU may continuously monitor for WTRUs between RA windows, however the blind retransmission grant 422 is opportunistic and the network may always choose not to provide one. This may result in additional and unnecessary WTRU power consumption, considering that the WTRU-gNB RTT 518 may be quite long.

In an embodiment, general solution components to support blind MSG3 retransmission enhancement in non-terrestrial networks are schematically illustrated in fig. 6 and may include, for example, a preamble transmission 610 that may optionally indicate WTRU coverage conditions (e.g., a partition from a preamble index or RACH occasion), a trigger condition 612 to perform additional PDCCH monitoring for blind retransmission grant reception, an optional configuration 614 for the WTRU to override 620 the triggered additional monitoring occasion based on override decision 616, and to perform additional PDCCH monitoring 618 for blind MSG3 retransmission grant reception. The following is an exemplary description of embodiments in which these component solutions may be combined.

The term "fast blind MSG3 retransmission grant reception" as used herein refers to the reception of a retransmission grant earlier than the WTRU-gNB RTT after an initial MSG3 transmission. The solutions described herein may be applied to any device operating in a non-terrestrial network (e.g., NTNWTRU, VSAT terminal, NB-IoT, and/or eMTC device) or in other network deployments with large WTRU-gNB RTTs.

The embodiments described herein may be primarily directed to additional PDCCH monitoring occasions after an initial MSG3 transmission in a non-terrestrial network, however, the embodiments described herein may also be applied to support blind re-authorization reception of transmissions other than MSG3 transmissions (e.g., other RRC messages or even user plane data).

Channel conditions may refer to any condition related to the state of a radio/channel that may be determined by a WTRU from WTRU measurements (e.g., L1/SINR/RSRP, CQI/MCS, channel occupancy, RSSI, power headroom (headroom), exposure headroom), L3/mobility based measurements (e.g., RSRP, RSRQ), RLM status, and/or channel availability in the unlicensed spectrum (e.g., LBT based determination of whether a channel is occupied).

PRACH resources herein refer to PRACH resources (e.g., in frequency), PRACH occasions (ROs) (e.g., in time), preamble formats (e.g., in terms of total preamble duration, sequence length, guard duration, and/or in terms of length of cyclic prefix), and/or some preamble sequence used to transmit a preamble in a random access procedure.

The nature of the scheduling information (e.g., uplink grant or downlink allocation) may include, for example, at least one of a frequency allocation, an aspect of a 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 carry, a TCI state or SRI, a number of repetitions, and whether the grant is a configured grant type 1, type 2, or dynamic grant.

For example, the indication or indication by DCI may include at least one of an explicit indication by DCI field or by RNTI for masking a CRC of the PDCCH, an implicit indication by a property such as a DCI format, DCI size, core set or search space, aggregation level, identification of a first control channel resource for DCI (e.g., index of a first CCE), where a mapping between the property and value may be signaled by RRC or MAC, and an explicit indication by DL MAC CE.

The considerations of WTRU power saving (i.e., ensuring that the WTRU performs additional monitoring only when a blind retransmission grant is expected), limited ability to expect signaling/indication of a blind retransmission grant because of limited opportunities for DL signaling, WTRU coverage scenarios may vary greatly due to cell size in NTN, which may complicate broadcast signaling, and different scenarios (e.g., two-step RACH backoff, RACH to idle/inactive in CONN, ioTNTN to NRNTN, priority of access attempts, number of failed RACH attempts, distance from cell center, etc.) may require differentiated WTRU behavior.

The following common benefits may result from embodiments described herein that allow a WTRU to perform limited additional PDCCH monitoring during random access, allow for trade-offs between WTRU power consumption, and additional scheduler flexibility of the network. This ensures that the WTRU monitors for blind MSG3 retransmission grants only when blind MSG3 retransmission grants are expected or in scenarios when blind MSG3 retransmission grants are most needed.

In some embodiments, the WTRU may use one or more of the solutions described below to indicate, for example, that the WTRU supports additional monitoring of enhanced blind MSG3 retransmissions (e.g., the WTRU supports this as WTRU capability), that the WTRU is in a coverage limited scenario (e.g., the WTRU may benefit from additional coverage enhancements such as additional blind MSG3 retransmissions), and that the WTRU may perform additional monitoring of blind MSG3 retransmission grants, and that the WTRU may request additional blind MSG3 retransmission grants.

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

The WTRU may request, indicate its capabilities, its coverage scenarios, or it will perform additional monitoring for enhanced blind MSG3 retransmissions via an implicit indication, where the WTRU may transmit PRACH at a particular random access occasion (e.g., within a set of RACH occasions reserved for/associated with such WTRU, where the WTRU may use a combination of PRACH preambles and random access occasions).

The WTRU may request, indicate its capability, its coverage scenario, or that it is to perform additional monitoring for enhanced blind MSG3 retransmissions via an implicit indication, where the WTRU may send the PRACH preamble more than once (e.g., twice) to indicate that it supports opportunistic blind MSG3 retransmissions, e.g., in more than one RO (e.g., a specific combination) or using more than one preamble to send the preamble transmission.

The WTRU may report capabilities and/or coverage characteristics by an explicit indication of WTRU capabilities for enhanced blind MSG3 retransmission, where 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 grants), a field that may indicate one or more aspects (e.g., that the WTRU is in an coverage limited scenario and supports additional monitoring), or an index to one or more preconfigured meanings. In one example, the WTRU may include the indication within a RACH message, such as within MSGA PUSCH resources. For example, the WTRU may instruct the WTRU to support additional blind MSG3 retransmissions and/or to perform additional monitoring in the case where the WTRU may fall back to the four-step RACH. In another example, the WTRU may include an indication via RRC signaling, such as within WTRU capability transmissions (e.g., during a connection to RRC connected mode). The WTRU may apply the indicated behavior, e.g., for a subsequent random access procedure. In another solution, the WTRU may include the information in a WTRU information response message (e.g., in response to a WTRU information request message).

The WTRU may report capabilities and/or coverage characteristics by a conditional indication of the capabilities for enhanced blind MSG3 retransmission, where the WTRU may send an indication to the network based on its power/battery level. For example, a WTRU with such capability but with a full battery (or, for example, or currently charging) may refrain from sending the indication. In another example, the WTRU may send one indication associated with a range of power levels, another indication associated with a range of other power levels, and so on.

The WTRU may report capabilities and/or coverage characteristics by a conditional indication of capabilities for enhanced blind MSG3 retransmission, wherein the WTRU may send an indication depending on whether it is coverage limited. For example, the WTRU may include in one or more of the following scenarios indicating and/or selecting PRACH partitions associated with limited coverage, a measurement/signal level based determination of coverage, if the signal level (e.g., RSRP) of the serving cell is below a certain level, but may avoid doing so if the signal level of the serving cell is above a certain level. The WTRU may send one indication associated with one range of serving cell signal levels, another indication associated with another range of serving cell signal levels, and so on.

The WTRU may report capability and/or coverage characteristics by a conditional indication of capability for enhanced blind MSG3 retransmission, where if the distance between the WTRU's location (e.g., acquired via GNSS) and the serving satellite is above a threshold, but if the signal level of the serving cell is above a certain level, this may be avoided. This may be avoided if the distance between the location of the WTRU (e.g., acquired via GNSS) and the serving cell reference point is above a threshold, but if the signal level of the serving cell is above a certain level.

In another embodiment, the WTRU may send an indication to the network based on its mobility state. For example, if the WTRU is in a high mobility state, the WTRU may include the indication, but otherwise avoid doing so. In another example, the WTRU may send one indication associated with a low mobility state, another indication associated with a medium mobility state, another indication associated with a high mobility state, and so on.

In another embodiment, the WTRU may send the indication based on an indication received in broadcast signaling. For example, the network may enable blind MSG3 retransmission by including an indication in the system information block, and if the WTRU receives the indication, the WTRU may send a capability indication. In some examples, the network may indicate the type of blind retransmission that is enabled (e.g., different modes of operation or different parameters), and the WTRU may determine whether the WTRU supports the indicated type and based on the 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 the feature and whether the WTRU may send an indication of the capability.

Additional PDCCH monitoring for enhanced blind MSG3 retransmission grant reception may be predefined, configured by the network, and/or explicitly indicated. Such a configuration may be used to support one or more of the solutions described herein and may include one or more of a preamble or RACH occasion associated with such capability, as well as any dependency on previously described coverage limits, battery levels or mobility states, etc., an indication of additional monitoring of blind MSG3 retransmissions performed (e.g., enable/disable configuration), a mapping between characteristics of MSG3 retransmission behavior and additional monitoring of blind MSG3 retransmissions, conditions (e.g., associated thresholds and/or threshold ranges) for performing additional blind MSG3 retransmissions, whether additional monitoring is performed based on failure conditions (e.g., number of transmission attempts prior to additional monitoring after a back-off from a two-step RACH to a four-step RACH, etc.), conditions of additional monitoring of blind MSG3 retransmission grants (e.g., threshold, prohibit timer duration), and/or characteristics of how additional monitoring should be performed (e.g., start, duration, periodicity).

The WTRU may be configured to monitor (receive) the PDCCH in a set of occasions during a random access procedure. The WTRU may determine the set of PDCCH monitoring occasions by monitoring according to a DRX configuration for random access, wherein in an embodiment the WTRU may determine the set of PDCCH monitoring occasions according to at least one DRX configuration and operation. Such a 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 start offset, a DRX short cycle, a DRX slot offset, and the like. The WTRU may monitor the PDCCH while at least one of a DRX on duration timer or a DRX inactivity timer is running. The WTRU may restart the inactivity timer when it receives the PDCCH scrambled with the TC-RNTI.

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

The WTRU may determine the set of PDCCH monitoring occasions through configured signaling, wherein the WTRU may receive values of at least one parameter of the configuration for PDCCH monitoring from RRC, MAC or DCI signaling. The WTRU may receive a plurality of configurations for PDCCH monitoring, each configuration identified by an index, and receive an indication of an applicable configuration from the signaling. One configuration may correspond to each possible monitoring occasion, e.g., a WTRU in each slot monitoring PDCCH. The configuration may be specific to, for example, one or more of a cell (e.g., a serving cell), a group of cells, a satellite, and an orbit or orbit classification (e.g., GEO or LEO). For example, the WTRU may determine the at least one value based on system information, based on a dedicated RRC message (RRC reconfiguration, RRC connection release), based on a field of a Random Access Response (RAR) message, or based on a nature of a RAR grant. For example, the WTRU may determine the values of the periodicity, the on-duration, and/or the configuration index based on a number of most or least significant bits of a Modulation and Coding Scheme (MCS) field, or based on a Time Domain Resource Allocation (TDRA) field, or based on a back-off indicator (BI) field. The mapping between bits and corresponding values may be predefined or may be signaled by RRC.

In the case where the WTRU determines the set of PDCCH monitoring occasions through configured signaling, the WTRU may determine the value of at least one parameter or configuration index based on the same condition(s) used to determine the preamble or the number of preamble repetitions. For example, the WTRU may determine the value of the configuration index based on path loss estimates or RSRP measurements made on resources such as SSBs.

In the case where the WTRU determines the set of PDCCH monitoring occasions through signaling of the configuration as described above, 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 with preamble selection and then determine the applicable configuration index values from the set based on the fields of the RAR.

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

The WTRU may apply the PDCCH monitoring mode when one of the reception of the RAR, or the start (or end) of the initial transmission of the Msg3 PUSCH occurs. In an embodiment, the WTRU may cease applying the PDCCH monitoring mode when at least one of a successful contention resolution, receiving a PDCCH for the C-RNTI, the number of repetitions and/or retransmissions of the Msg3 PUSCH reaching a predefined or configured threshold, RRC signaling (e.g., connection setup or reconfiguration) indicating an applicable DRX configuration, and/or after a configured or predefined period since the WTRU began to apply to the monitoring mode.

In an embodiment, the configuration of/indicated by the network may be received with the first message and may then be enabled/disabled by NW signaling in the second message (e.g., MAC CE, DCI, SIB, RRC, RACH message, etc.).

The WTRU may receive an indication of an additional PDCCH monitoring occasion/period from the network to check for authorization of the blind Msg3 retransmission. The WTRU then performs PDCCH monitoring during the indicated occasion/period following the initial transmission of Msg 3.

The WTRU may receive an indication of an additional PDCCH monitoring occasion/period from the network to check for authorization of the blind Msg3 retransmission, wherein the WTRU may receive a configuration for a first PDCCH monitoring (e.g., normal PDCCH monitoring) for the blind Msg3 retransmission.

The WTRU may receive an indication of an additional PDCCH monitoring occasion/period from the network to check for authorization of the blind Msg3 retransmission, wherein the WTRU may receive configuration information associated with performing a second PDCCH monitoring (e.g., additional PDCCH monitoring) for blind Msg3 retransmission authorization reception or an indication (e.g., explicit indication) of a second PDCCH monitoring (e.g., additional PDCCH monitoring) to be performed for blind Msg3 retransmission authorization reception, wherein in an example the second PDCCH monitoring may be performed prior to the first PDCCH monitoring (the configuration information or indication may be provided in, for example, system information, RRC release message, handover command, and/or RACH configuration; the configuration information or indication may include when and/or how to perform the second PDCCH monitoring (e.g., start a new timer for Xms, start monitoring at some periodicity, start monitoring at a Z offset from RAR reception or from Msg3 transmission)).

The WTRU may receive an indication of an additional PDCCH monitoring occasion/period from the network to check for authorization of a blind Msg3 retransmission, where the WTRU may select and transmit a PRACH preamble. The preamble may optionally be partitioned and the WTRU may select a preamble indicating at least one of that the WTRU is in a coverage limited scenario, that the WTRU supports and/or will perform a second (e.g., additional) PDCCH monitoring, and a request for a blind retransmission grant based on or using the second (e.g., additional) PDCCH monitoring.

The WTRU may receive an indication of an additional PDCCH monitoring occasion/period from the network to check for authorization of a blind Msg3 retransmission, where the WTRU may start ra-ResponseWindow and monitor the PDCCH for a random access response.

The WTRU may receive an indication of an additional PDCCH monitoring occasion/period from the network to check for authorization of the blind Msg3 retransmission, where the WTRU may receive the random access response and stop ra-ResponseWindow. In an example embodiment, the random access response may include an indication (e.g., an explicit indication) to perform a second (e.g., additional) PDCCH monitoring for blind MSG3 retransmission grants. The indication may, for example, activate the WTRU or indicate to the WTRU to perform the second PDCCH based on the configuration information.

The WTRU may receive an indication of an additional PDCCH monitoring occasion/period from the network to check for grants for blind Msg3 retransmissions, where the WTRU may transmit at least one Msg3 based on the received RAR (e.g., based on UL grants received in the RAR).

The WTRU may receive an indication of an additional PDCCH monitoring occasion/period from the network to check for grant of blind Msg3 retransmission, wherein the WTRU may monitor the PDCCH in the monitoring occasion based on the received configuration and/or indication for the second PDCCH monitoring for the blind Msg3 retransmission grant. In embodiments, these may be at a second or additional occasion.

The WTRU may receive an indication of an additional PDCCH monitoring occasion/period from the network to check for grants for blind Msg3 retransmissions, wherein when the WTRU receives a PDCCH based on the second PDCCH monitoring, the WTRU retransmits at least one Msg3 based on the grants received in the PDCCH (e.g., in DCI carried by the PDCCH), for example.

The WTRU may receive an indication of an additional PDCCH monitoring occasion/period from the network to check for grants of blind Msg3 retransmissions, wherein after monitoring the PDCCH based on the second PDCCH monitoring, the WTRU may monitor the PDCCH based on the first PDCCH monitoring and transmit at least one Msg3 when the PDCCH is received (e.g., with UL grants).

In an embodiment, the WTRU may receive explicit indications, e.g., via one or more of a random access response (e.g., msg 2), a PDCCH command, SIB signaling (e.g., SIB19, SIB31, and/or SIB 32), a paging message (e.g., CN page, RAN page, etc.), e.g., while the WTRU is idle/inactive, a handover command (e.g., within reconfigurationWithSyncIE of an RRC reconfiguration message), an RRC release message when the WTRU transitions from a connected state to idle/inactive, and an RRC reconfiguration message that is neither an HO command nor an RRC release, indicating to the WTRU the arrival of DL data.

In embodiments, the WTRU may receive an explicit indication, wherein the WTRU may be configured to use the received indication/configuration only when it transitions to a connected state within a validity time.

In an embodiment, the WTRU may receive an explicit indication, wherein a validity area (e.g., a 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 reselection outside the validity area.

In an embodiment, the WTRU may receive an explicit indication, where the indication includes certain timing information (e.g., exact frame/slot, etc.) when an grant for Msg3 retransmission is expected to be received in the PDCCH.

In an embodiment, the WTRU may receive an explicit indication, wherein the indication includes a time window in which an grant of Msg3 retransmissions is expected to be received in the PDCCH (e.g., between frames/slots n and m, between times t1 and t2, etc.). In one solution, the indication may include timing information for the grant of multiple retransmissions. For example, the indication may include periodic information (e.g., an expected grant every n frames/slots since the indication was received or some other point in time). The indication may be aperiodic or quasi-periodic (e.g., the authorizations expected at t1, t2, t3.. Wherein the duration between t1 and t2 and between t2 and t3 is different).

In an embodiment, the WTRU may receive an explicit indication, wherein the indication may be an agreed (agreedupon) configuration that depends on an indication received from the WTRU indicating the capabilities and conditions/requirements of the WTRU. For example, for a particular PRACH preamble or PRACH occasion used by the WTRU (which may depend on WTRU capabilities/conditions/requirements as described herein), the WTRU will know when to monitor the PRACH for grants for MSG3 retransmissions. The WTRU may be preconfigured with this mapping between the indication from the WTRU and the PDCCH monitoring occasion/duration/window for MSG3 (e.g., mapping specified in 3GPP standards, SIB, RRC signaling, mapping indication in MAC signaling, etc.).

The above embodiments, in which additional PDCCH monitoring is triggered by explicit indication and/or configuration, are described further below and with respect to the exemplary flowchart of fig. 7.

At 710, the WTRU receives a configuration for a first PDCCH monitoring (e.g., normal PDCCH monitoring) for MSG3 retransmissions.

At 712, the WTRU receives configuration information associated with performing a second PDCCH monitoring (e.g., additional PDCCH monitoring) for blind MSG3 re-authorization reception or an indication (e.g., explicit indication) of performing a second PDCCH monitoring (e.g., additional PDCCH monitoring) for blind MSG3 re-authorization reception, wherein the second PDCCH monitoring may be performed prior to the first PDCCH monitoring in an example. Configuration information or indication may be provided in, for example, system information, RRC release message, handover command, and/or RACH configuration. The configuration information or indication may include when and/or how to perform the second PDCCH monitoring (e.g., starting a new timer for X ms, monitoring at some periodicity, starting monitoring at a Z offset received from the RAR or transmitted from the MSG 3).

At 714, the WTRU selects and transmits a PRACH preamble. The preamble may optionally be partitioned and the WTRU may select a preamble indicating at least one of that the WTRU is in a coverage limited scenario, that the WTRU supports and/or will perform a second (e.g., additional) PDCCH monitoring, and a request for a blind retransmission grant based on or using the second (e.g., additional) PDCCH monitoring.

At 716, the WTRU starts ra-ResponseWindow and monitors the PDCCH for a random access response.

At 718, the WTRU receives the random access response and stops ra-ResponseWindow. In an example, the random access response may include an indication (e.g., an explicit indication) to perform a second (e.g., additional) PDCCH monitoring for blind MSG3 retransmission grants. The indication may, for example, activate the WTRU or instruct the WTRU to perform a second WTRU based on the configuration information.

At 720, the WTRU transmits at least one MSG3 based on the received RAR (e.g., based on UL grant received in the RAR).

At 722, the WTRU monitors the PDCCH in a monitoring occasion based on the received configuration and/or indication for a second PDCCH monitoring (e.g., at a second or additional occasion) for a blind MSG3 retransmission grant.

At 724, when the WTRU monitors for receipt of the PDCCH based on the second PDCCH, the WTRU retransmits at least one MSG3 based on, for example, grants received in the PDCCH (e.g., in DCI carried by the PDCCH).

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

The WTRU may perform additional PDCCH monitoring triggered based on Msg3 repetition characteristics, wherein the WTRU may perform additional PDCCH monitoring for enhanced blind Msg3 retransmission grants based on the characteristics of the Msg3 repetition. The WTRU may have different behaviors based on whether the WTRU performs random access in RRC idle/inactive or in RRC connection.

In an embodiment, the WTRU may perform additional PDCCH monitoring triggered based on the Msg3 repetition characteristic, as shown in fig. 8. At 810, the WTRU receives a configuration for a first PDCCH monitoring (e.g., normal PDCCH monitoring) for MSG3 retransmissions. At 812, the WTRU receives configuration information associated with performing a second PDCCH monitoring (e.g., additional PDCCH monitoring) for blind MSG3 re-authorization reception, wherein the second PDCCH monitoring may be performed prior to the first PDCCH monitoring in an example. At 814, the WTRU selects and transmits a PRACH preamble. The preambles may optionally be partitioned and the WTRU may select a preamble indicating at least one of that the WTRU is in a coverage limited scenario, that the WTRU supports and/or will perform second (e.g., additional) PDCCH monitoring, and that a request for blind retransmission grants based on or using the second (e.g., additional) PDCCH monitoring. At 816, the WTRU starts ra-ResponseWindow and monitors the PDCCH for a random access response. At 818, the WTRU receives a Random Access Response (RAR) indicating that MSG3 is repeated and stops ra-ResponseWindow. The number of MSG3 repetitions to be performed may be indicated by or determined from the content of the RAR and/or may be based on the 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 whether to perform a second (e.g., additional) PDCCH monitoring for blind MSG3 retransmissions based on at least one MSG3 repetition characteristic and/or an override condition. In an embodiment, the MSG3 characteristic is the number of MSG3 repetitions configured or indicated. The relationship between the second (e.g., additional) PDCCH monitoring and the number of MSG3 repetitions may be predefined, configured (e.g., in RACH configuration, RRC release message, or HO command) or indicated, e.g., in system information or RAR. In an example, the relationship may be identified to perform a second PDCCH monitoring when the number of MSG3 repetitions is above or below a defined or configured value or threshold. In an embodiment, override conditions may be configured. The override condition may be based on, for example, RSRP or a range threshold (e.g., provided in SIB, RRC message, RRC release, etc.), and when, for example, RSRP is above the RSRP threshold and/or a range (e.g., from WTRU) to satellite is within a range threshold (e.g., X km) (e.g., below the range threshold (e.g., xkm)). If this condition is met, the WTRU does not perform a second (e.g., additional) PDCCH monitoring.

If the repeated characteristics of MSG3 indicate that a second (e.g., additional) monitoring is performed, and/or an optional override condition is not met, then at 824 the WTRU monitors the PDCCH in a monitoring occasion (e.g., based on a received configuration) for a second PDCCH monitoring for a blind MSG3 retransmission grant (e.g., in a second or additional occasion). When the WTRU monitors for receipt of a PDCCH based on the second PDCCH, the WTRU retransmits at least one MSG3 based on the grant received in the PDCCH (e.g., PDCCH DCI) at 826. In further embodiments, at 828, after monitoring the PDCCH based on the second PDCCH monitoring, the WTRU monitors the PDCCH based on the first PDCCH monitoring and transmits at least one MSG3 when a PDCCH with UL grant (e.g., PDCCH DCI) is received.

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

Whether the WTRU performs additional monitoring of the grant of blind MSG3 transmissions based on the MSG3 repetition feature may be based on the configuration. For example, the configuration may be present in the system information, where additional monitoring may be explicitly enabled/disabled, or alternatively, the presence of parameters may indicate that additional monitoring for blind retransmissions is enabled. In another example, the indication/configuration may be provided via RRC signaling (e.g., RRC release with suspension, or RRC reconfiguration), via a random access message (e.g., RAR, MSGB), MAC CE, paging message, or DCI.

Whether the WTRU performs additional monitoring of the grant of blind MSG3 transmissions based on the MSG3 repetition characteristics may be based on a configuration, where the configuration/indication may describe an action to be applied, such as one or more of 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).

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

The WTRU may perform additional monitoring of the blind MSG3 retransmission grant based on whether the MSG3 repetition is a transmission indication, and the WTRU may perform one or more of the following that the WTRU may receive a configuration for a first PDCCH monitoring (e.g., normal PDCCH monitoring) for the blind MSG3 retransmission. The WTRU may receive configuration information associated with performing a second PDCCH monitoring (e.g., additional PDCCH monitoring) for authorization of reception for blind MSG3 retransmissions, wherein the second PDCCH monitoring may be performed prior to the first PDCCH monitoring in an example. The WTRU may select and transmit a PRACH preamble. (the preamble may optionally be partitioned and the WTRU may select a preamble indicating at least one of that the WTRU is in a coverage limited scenario, that the WTRU supports and/or will perform second (e.g., additional) PDCCH monitoring, that the WTRU may start ra-ResponseWindow for a request for blind retransmission grant based on or using the second (e.g., additional) PDCCH monitoring, and monitor the PDCCH for a random access response. The WTRU may receive a Random Access Response (RAR) that does not indicate MSG3 repetition and stops ra-ResponseWindow. The WTRU may transmit at least one MSG3 based on the received RAR (e.g., based on the UL grant received in the RAR). Based on the lack of MSG3 repetition, the WTRU may monitor the PDCCH in a monitoring occasion (e.g., based on the received configuration) for a second PDCCH monitoring for a blind MSG3 retransmission grant (e.g., at a second or additional occasion).

The WTRU may receive a mapping between MSG3 repetition characteristics and additional monitoring for blind MSG3 re-authorization reception. Based on the configured mapping behavior, upon receiving the MSG3 grant, the WTRU will determine additional blind MSG3 monitoring behavior based on the MSG3 retransmission characteristics. In an embodiment, whether the WTRU performs additional monitoring may be mapped to (i.e., a function of) a certain number of MSG3 retransmissions. For example, similar to table 1 below, the wtru may be configured to perform additional monitoring of MSG3 grants.

TABLE 1

The WTRU may receive a mapping between MSG3 repetition characteristics and additional monitoring for blind MSG3 retransmission grant reception, where in further embodiments additional monitoring characteristics (e.g., start, duration, periodicity) may be mapped to a certain number of MSG3 retransmissions. For example, similar to table 2 below, the wtru may be configured to perform additional monitoring for MSG3 grants:

TABLE 2

The WTRU may receive a mapping between the MSG3 repetition characteristic and additional monitoring of blind MSG3 retransmission reception, where in further embodiments the WTRU may receive the mapping information, e.g., via RRC signaling or MAC CE. In one example, the WTRU may receive information within a handover command (e.g., and RRC reconfiguration with synchronization message) for random access to the target cell.

For example, as described in connection with fig. 9, the WTRU may perform additional PDCCH monitoring for enhanced MSG3 blind retransmission grants based on meeting the conditions and/or the combination of conditions.

At 910, the WTRU may receive a configuration for a first PDCCH monitoring (e.g., normal PDCCH monitoring) of MSG3 retransmissions. At 912, the WTRU receives configuration information associated with a second PDCCH monitoring (e.g., additional PDCCH monitoring) that performs a second grant of authorization reception for the blind MSG3, wherein the second PDCCH monitoring may be performed prior to the first PDCCH monitoring in an example. At 914, the WTRU receives a condition to perform a second (e.g., additional) PDCCH monitoring of the blind MSG3 retransmission. In an embodiment, the condition may be based on one or more values, for example, one or more of a distance from a center of the cell, an angle of the satellite relative to the earth, and/or RSRP. In further embodiments, the configuration or identification of which value or values to evaluate and the associated threshold value or thresholds against which to evaluate (e.g., evaluate the value or values) may be provided, for example, in system information, HO command, RRC release message, or RAR. At 916, the WTRU selects and transmits a RACH preamble. The preambles may optionally be partitioned and the WTRU may select a preamble indicating at least one of that the WTRU is in a coverage limited scenario, that the WTRU supports and/or will perform second (e.g., additional) PDCCH monitoring, and that a request for blind retransmission grants based on or using the second (e.g., additional) PDCCH monitoring. At 918, the WTRU starts ra-ResponseWindow and monitors the PDCCH for a random access response. At 920, the WTRU receives the random access response and stops ra-ResponseWindow. At 922, the WTRU transmits at least one MSG3 based on the received RAR (e.g., based on UL grants received in the RAR). At 924, the WTRU determines whether to perform a second (e.g., additional) PDCCH monitoring for blind MSG3 retransmissions based on the configured condition (e.g., based on whether one or more values are above or below its associated threshold). If one or more conditions for second (e.g., additional) PDCCH monitoring are met, the WTRU monitors the PDCCH in a monitoring occasion (e.g., based on a received configuration) for second PDCCH monitoring for blind MSG3 retransmission grants (e.g., at a second or additional occasion) at 926. When the WTRU monitors for receipt of the PDCCH based on the second PDCCH, the WTRU retransmits at least one MSG3 based on the grant received in the PDCCH (e.g., PDCCH DCI) at 928. In an embodiment, after monitoring the PDCCH based on the second PDCCH monitoring, the WTRU monitors the PDCCH based on the first PDCCH monitoring and transmits at least one MSG3 when a PDCCH with UL grant (e.g., PDCCH DCI) is received at 930.

The WTRU may perform additional PDCCH monitoring for enhanced MSG3 blind retransmission grants based on meeting a condition and/or a combination of conditions, wherein the condition for additional PDCCH monitoring for enhanced blind MSG3 retransmission grants may include one or more of a threshold, wherein the condition may be met, for example, if the measurement is above, below, or equal to the threshold, a particular value, wherein the condition may be met, for example, if the measurement is equal to one or more indication values, a range of values, wherein the condition may be met, for example, if the measurement is within the range. Alternatively, the condition may be satisfied if the measured value falls outside the indicated range.

The WTRU may perform additional PDCCH monitoring for enhanced MSG3 blind retransmission grants based on meeting conditions and/or combinations of conditions, wherein the WTRU may be configured with distance-based conditions for determining parameters, behaviors, etc. The distance may be defined as one or more of a WTRU-satellite distance, a distance between a WTRU-satellite cell center, a distance between a WTRU and a satellite coverage area (footoprint), a distance between a WTRU and a ground-based gNB, or a distance between a WTRU and a reference point. The distance-based condition may be in the form of the WTRU reaching at least or at most a certain distance. For example, the distance of the WTRU is above a configured threshold, the distance of the WTRU is below a configured threshold, and/or the distance of the WTRU is between two configured thresholds. The distance-based condition may be in the form of a change in the distance of the WTRU. In an embodiment, the condition may be that the distance of the WTRU may change by an amount greater than the threshold value within the configured time period/duration, the distance of the WTRU may increase by an amount greater than the threshold value within the configured time period/duration, the distance of the WTRU may decrease by an amount greater than the threshold value within the configured time period/duration, the change in the distance of the WTRU may have increased by an amount greater than the threshold value within the configured time period/duration, or the change in the distance of the WTRU may have decreased by an amount greater than the threshold value within the configured time period/duration.

The distance-based condition may be in the form of the time the WTRU spends at a distance. For example, the distance of the WTRU may remain at the same value for at least a configured period of time, the distance of the WTRU may remain within a configured range for at least a configured period of time, the distance of the WTRU may change less than a configured amount over a configured period of time, and/or the WTRU may spend a maximum amount of time at a distance over a configured period of time.

The WTRU may perform additional PDCCH monitoring for enhanced MSG3 blind retransmission grants based on meeting conditions and/or combinations of conditions, wherein the WTRU may be configured with speed-based conditions for determining parameters, behavior, etc. The speed-based condition may be in the form of the WTRU reaching at least or at most a certain speed. For example, the speed of the WTRU is above a configured threshold, the speed of the WTRU is below a configured threshold, and/or the speed of the WTRU is between two configured thresholds. The speed-based condition may be in the form of a change in the speed of the WTRU (e.g., acceleration/deceleration). In an embodiment, the condition may be that the speed of the WTRU may change by an amount greater than a threshold value over a period of time, that the speed of the WTRU may increase by an amount greater than a threshold value over a period of time, or that the speed of the WTRU may decrease by an amount greater than a threshold value over a period of time. The speed-based condition may be in the form of time the WTRU spends at a certain speed. In an embodiment, the condition may be that the speed of the WTRU remains at the same value for at least a configured period of time, the speed of the WTRU remains within a configured range for at least a configured period of time, the speed of the WTRU changes by more/less than a configured amount over the configured period of time.

The WTRU may perform additional PDCCH monitoring for enhanced MSG3 blind retransmission grants based on meeting conditions and/or combinations of conditions, wherein the WTRU may be configured with satellite-based conditions based on determining parameters, behaviors, etc. In embodiments, satellite-based conditions may depend on satellite characteristics, which may be explicitly indicated or implicitly determined (e.g., via satellite ephemeris). In an embodiment, satellite conditions may be based on one or more of differential delay within a cell (e.g., differential delay above, below, or within range), size and/or coverage area of a cell (e.g., cell coverage area above, below, or within range), remaining t-services of a cell (e.g., remaining t-services above, below, or within range), a gap between t-services of a current cell and t-service initiation of a neighboring cell (e.g., whether there is continuous coverage or discontinuous coverage), whether satellite payload is configured with an earth fixed beam or an earth moving beam, an orbit classification of a satellite (e.g., whether satellite is GEO, LEO, MEO or HAPS)), or an angle of a satellite relative to the earth.

The WTRU may perform additional PDCCH monitoring for enhanced MSG3 blind retransmission grants based on meeting conditions and/or a combination of conditions, wherein the WTRU may be configured with channel-based conditions for determining parameters, behavior, etc. Embodiments of channel-based conditions may include one or more of measuring channel conditions below or above a threshold (e.g., RSRP, RSRQ), applying TA estimation/WTRU-gNB RTT (e.g., applying timing pre-compensation above, below, or within range), and/or frequency compensation (e.g., applying frequency compensation above, below, or within range).

The WTRU may perform additional PDCCH monitoring for enhanced MSG3 blind retransmission grants based on meeting conditions and/or combinations of conditions, where there may be a correlation between WTRU coverage characteristics and/or WTRU location and NW decisions using blind MSG3 retransmission where WTRU conditions may be evaluated with limited capabilities at the WTRU to coordinate with the network whether the conditions are met and the WTRU performs additional monitoring. In an embodiment, the WTRU may explicitly indicate that a condition has been met (e.g., transmission via a dedicated preamble, or within the MSA PUSCH.

The WTRU may perform additional PDCCH monitoring for blind MSG3 retransmission grants based on the failure condition, as described below and with reference to fig. 10A and 10B. At 1012, the WTRU receives configuration information associated with performing a second PDCCH monitoring (e.g., additional PDCCH monitoring) for authorization reception for blind MSG3 retransmissions, wherein the second PDCCH monitoring may be performed prior to the first PDCCH monitoring in an example. At 1014, the WTRU initiates two-step random access through a transmission that includes a preamble and MSGA of a PUSCH transmission. The preambles may optionally be partitioned and the WTRU may select a preamble indicating at least one of WTRU information or WTRU requests that the WTRU is in a coverage limited scenario, that the WTRU supports and/or will perform a second (e.g., additional) PDCCH monitoring, a request for blind retransmission grants based on or using the second (e.g., additional) PDCCH monitoring. WTRU information and/or requests may optionally be included in MSGA PUSCH. At 1016, the WTRU starts msgB-ResponseWindow and monitors the PDCCH for MSGB carrying a random access response. At 1018, the WTRU receives a random access response, wherein the RAR triggers a back-off to the four-step RA and stops msgB-ResponseWindow. At 1020, the WTRU transmits at least one MSG3 based on the received RAR (e.g., based on UL grants received in the RAR). In an embodiment, the WTRU evaluates the override condition, if configured, at 1022. In an embodiment, the override condition may be based on the RSRP or a range threshold (e.g., provided in SIB, RRC message, 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 a range threshold (e.g., X km) (e.g., below the range threshold (e.g., X km)). If the override condition is met, the WTRU determines that a second (e.g., additional) PDCCH monitoring is not performed at 1024. If the override condition is not met, the WTRU determines to perform a second (e.g., additional) PDCCH monitoring (based on the backoff trigger) at 1026.

The WTRU may perform additional PDCCH monitoring for the blind MSG3 re-authorization based on the failure condition, wherein in further embodiments, an example of which is shown in fig. 10B, based on the backoff trigger, at 1030 the WTRU determines to perform a second (e.g., additional) PDCCH monitoring. If the WTRU determines to perform second (e.g., additional) PDCCH monitoring, at 1032 the WTRU monitors the PDCCH in a monitoring occasion (e.g., based on the received configuration) for second PDCCH monitoring for blind MSG3 retransmission grants (e.g., at a second or additional occasion). When the WTRU monitors receiving PDCCH based on the second PDCCH, the WTRU retransmits at least one MSG3 based on the grant received in the PDCCH (e.g., PDCCH DCI). In an embodiment, after monitoring the PDCCH based on the second PDCCH monitoring, the WTRU monitors the PDCCH based on the first PDCCH monitoring and transmits at least one MSG3 when a PDCCH with UL grant (e.g., PDCCH DCI) is received. If the WTRU determines not to perform a second (e.g., additional) PDCCH monitoring, the WTRU monitors the PDCCH based on the first PDCCH monitoring and transmits at least one MSG3 when a PDCCH (e.g., PDCCH DCI) with a UL grant is received.

The failure condition may trigger additional monitoring of blind MSG3 retransmission grants. In an embodiment, the WTRU may begin a two-step RACH procedure (e.g., transmission via MSGA) and then begin monitoring the PDCCH for a response (e.g., subject to a 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 receiving the RAR after MSGA transmission, the WTRU may then transmit MSG3 and begin additional monitoring for blind MSG3 retransmission grants.

In further embodiments, the WTRU may transmit a random access preamble and begin monitoring for a response (e.g., subject to a ra-response window) in the event of a failure that may trigger additional monitoring of the blind MSG3 retransmission grant. For example, if the WTRU does not receive a Random Access Response (RAR) before the ra-response window expires, the WTRU may perform additional monitoring for blind MSG3 retransmission grants. In another example, the WTRU may perform additional monitoring if the WTRU does not receive a RAR within X ms of expiration of the ra response window.

In further embodiments, the WTRU may transmit one or more preambles without receiving a response from the network in the event of a failure that may trigger additional monitoring of the blind MSG3 retransmission grant. The WTRU may perform additional monitoring for blind MSG3 retransmission grants when Y unsuccessful transmissions (e.g., the WTRU does not receive a preamble transmission of a response). Y may be indicated, for example, within system information and RRC release/release or HO command with suspend message (e.g., RRC reconfiguration with synchronization).

The WTRU may avoid monitoring the PDCCH for grants for Msg3 retransmissions even if the network has implicitly or explicitly indicated to it to monitor the PDCCH at certain occasions/durations. For example, the WTRU may stop monitoring the PDCCH at the opportunity/duration for obtaining an indication of grant of Msg3 retransmission when it is determined that it is in good coverage condition (e.g., the signal level of the serving cell is above a configured threshold).

The WTRU may refrain from monitoring the PDCCH for grants for Msg3 retransmissions, where the WTRU may be configured to monitor the PDCCH for grants obtained for Msg3 retransmissions at t1, t2, and t3 (e.g., all within WTRU-gNB RTT times). The WTRU may monitor the PDCCH at t1, obtain authorization and perform retransmission. At this point, however, the WTRU may detect that the network conditions have improved substantially and it is likely that no more blind retransmissions are desirable for message 3. Thus, the WTRU may not monitor PDCCH at t2 and t 3. In one example, the WTRU may skip the additional PDCCH monitoring occasion if no DCI or PDCCH is received in a given PDCCH monitoring occasion addressed to the WTRU's calculated RA-RNTI or T-CRNTI.

The WTRU may avoid monitoring the PDCCH for grants for Msg3 retransmissions, where the WTRU may send an indication to the network that it did not monitor the PDCCH as previously configured. The indication may be included, for example, in one of the last repetitions of Msg3, where the WTRU has determined that no more repetitions are desired/needed. As another example, the indication may be a separate indication (e.g., UCI multiplexed on PUSCH).

The WTRU may avoid authorized monitoring of PDCCH for Msg3 retransmissions, wherein the WTRU may override or skip additional PDCCH monitoring occasions for configuration of Msg3 retransmissions if any of the above conditions are met or not met.

The WTRU may refrain from monitoring the PDCCH for grants for Msg3 retransmissions, wherein the WTRU may receive grants for RA-RNTI corresponding to the transmitted RO and preamble in either Msg2 or msgB with an associated plurality of temporary C-RNTI. If one condition is met (e.g., from the condition described in 4.6), the WTRU may select one temporary C-RNTI and transmit Msg3 with such TC-RNTI, while if the condition is not met or another condition is met, the WTRU may transmit Msg3 with a different signaled TC-RNTI. For example, the WTRU may receive grants in an RAR with 2 temporary C-RNTI, whereby the WTRU transmits Msg3 with a first signaled temporary C-RNTI if the measured RSRP is above a threshold, or Msg3 with a second signaled temporary C-RNTI if the measured RSRP is less than the threshold. The WTRU may implicitly determine the second temporary C-RNTI by adding an offset to the signaled first temporary C-RNTI portion 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 the second TC-RNTI if the second TC-RNTI is selected.

The WTRU may avoid monitoring the PDCCH for grants for Msg3 retransmissions, where the WTRU may be predefined or configured such that if the WTRU transmits Msg3 using the second temporary C-RNTI, the WTRU may skip additional monitoring occasions for Msg3 retransmissions. The WTRU may be configured or predefined such that if the first temporary C-RNTI is selected for the initial Msg3 transmission, the WTRU monitors additional PDCCH occasions for Msg3 retransmissions. The WTRU may monitor for Msg3 retransmission DCI scheduled using any of the temporary RNTIs signaled in the RAR, or (optionally in addition to) a temporary RNTI selected for the initial Msg3 transmission.

The WTRU may avoid monitoring the PDCCH for grants for Msg3 retransmissions, where the WTRU may be configured with multiple physical layer transmission Msg3 PUSCH parameters (e.g., transmission power, PUSCH scrambling sequence), where a first set of PHY transmission parameters is applied to Msg3 transmissions if the condition is met, and a second set of PHY transmission parameters(s) is used if the condition is not met (or a different condition is met). For example, the WTRU may be configured or predefined with two sequences to scramble the Msg3 PUSCH, whereby if the measured RSRP is less than a threshold, the WTRU transmits the Msg3 PUSCH scrambled by the first sequence, and if the measured RSRP is more than the threshold, the WTRU transmits the Msg3 PUSCH scrambled by the second sequence.

The WTRU may avoid monitoring the PDCCH for grants for Msg3 retransmissions, where 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. The conditions may include at least one condition as described above. The subset of grants may be used for Msg3 retransmission/repetition(s). The grant may be for the same HARQ process (e.g., HARQ PID 0) or a different PID.

The WTRU may refrain from monitoring the PDCCH for grants for Msg3 retransmissions, where the WTRU may receive multiple 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 one or more second grants repeatedly signaled for Msg3 if the condition is met. For example, the WTRU may receive more than one grant, whereby if the WTRU measures RSRP (e.g., SS-RSRP) above a threshold, the WTRU may select a first grant, and if the condition is not met (e.g., RSRP is less than the threshold), the WTRU may select secondary(s) grant (e.g., grant signaled for Msg3 retransmission). The WTRU may discard the unused or unselected secondary grants.

The WTRU may avoid monitoring the PDCCH for grants for Msg3 retransmissions, wherein the WTRU may select grants for Msg3 transmissions using a first HARQ process (e.g., HARQ process 0) if a condition (e.g., RSRP above a threshold) is met, or may select grants using a second HARQ process if the condition is not met.

The WTRU may continue to monitor the PDCCH based on ra-ResponseWindow, regardless of whether a RAR has been received. Fig. 11 shows an example in which, after RA preamble transmission 1110, RAR 1114 is received and there is a significant unused duration 1116 of response window 1112. 1116. As shown in fig. 12, after successful reception of the RAR 1114, the WTRU may continue to monitor the PDCCH for blind Msg3 re-authorization 1118. Whether the WTRU may continue to monitor may be conditioned on the time remaining in the RAR window. For example, the WTRU may use this embodiment only if more than X ms remains in the ra-ResponseWindow duration, which may be a better option for additional scheduling opportunities. In further embodiments, the WTRU will use this solution only if less than X ms remains in the ra-ResponseWindow duration, which may be a better option for additional power saving.

In further embodiments, as shown in fig. 13, the WTRU may begin ra-ContentionResolutionTimer 1318 immediately after the initial Msg3 transmission 1316 to monitor for additional blind Msg3 retransmission grants. In this case, a WTRU operating in a non-terrestrial network may start ra-ContentionResolutionTimer in the first symbol after the end of the initial Msg3 transmission 1316 to monitor for a blind Msg3 retransmission grant. In another example, the WTRU may start ra-ContentionResolutionTimer 1322 at some offset 1320 from the end of the initial MSG3 transmission. The WTRU may then start ra-Contention Resolution timer (contention resolution timer) 1322 a second time after the WTRU-gNB RTT 1320. The WTRU may ignore the expiration of ra-ContentionResolutionTimer for blind MSG3 retransmission grant reception when considering whether MSG3 transmission is successful or not.

In an embodiment, the WTRU may maintain an additional Msg3 re-TX timer, which the WTRU may start or resume at the beginning of each additional PDCCH monitoring occasion. The WTRU may monitor the PDCCH (e.g., for receiving Msg3 re-TX grants) while such a timer is running. The WTRU may (re) start the timer when (re) transmitting Msg 3. The WTRU may pause or stop the timer beyond the additional PDCCH monitoring occasions for the configuration of the Msg3 re-TX.

Upon expiration of this period, the WTRU may avoid or skip monitoring additional PDCCH monitoring occasions for the Msg3 re-TX. The WTRU may (re) start or stop the timer upon receiving a retransmission grant for an Msg3 retransmission. The WTRU may (re) start the timer when determining the HARQ NACK for the Msg3 payload. The WTRU may stop the timer when Msg4 is received or it determines HARQ-ACK for Msg3 payload or msgA payload as ACK. The WTRU may operate such a timer only if the ra-responsewindow, msgB-responsewindow and/or contention resolution timer is not running.

The WTRU may be configured (e.g., part of broadcasting SIB signaling) with whether the WTRU should monitor additional PDCCH occasions for scheduling Msg3 retransmissions, a configuration of additional PDCCH occasions for scheduling Msg3 retransmission modes (referred to herein as "Msg3 re-TX DRX modes"), applicable PDCCH resources, and/or timers associated with additional PDCCH monitoring for Msg3 re-TX. The "Msg3 re-TX DRX mode" configuration indicates at least one of the number of additional PDCCH occasions to monitor (e.g., after an initial Msg3 transmission and/or before a contention resolution timer starts), a start offset of PDCCH occasion(s), -e.g., an offset from PRACH resources, -periodicity between occasions, and/or one or more applicability conditions of such a mode, such as those listed herein above, and if a schedule is received on a given occasion within the mode, whether the additional occasion is monitored. The WTRU may monitor for additional PDCCH monitoring occasions for Msg3 re-TX if at least one of the conditions listed herein above is met or not met.

The WTRU may monitor for additional PDCCH monitoring occasions for Msg3 re-TX during configured paging occasions and/or paging PDCCH monitoring occasions of the one or more paging occasions. The WTRU may be configured, for example, with a portion of broadcast signaling, with a subset of paging PDCCH monitoring occasions and/or POs to monitor for receipt of Msg3 or msgA retransmission grants. The WTRU may implicitly determine a subset of PO or PDCCh monitoring opportunities within the PO to monitor for reception of Msg3 re-TX. For example, the WTRU may monitor one or more PO/paging monitoring occasions based on the timing of the PACH occasion selected for Msg1 transmission and/or based on the last Msg3 repeated transmission occasion. For example, if Msg3 is transmitted at t0, the WTRU may monitor for PO and/or PDCCH paging monitoring occasions starting from t1+δt, where δt is preconfigured, predefined, or implicitly determined by the WTRU as gNB-WTRURTT or a multiple thereof. In another example, if msg1 is transmitted on the RO at t0, and possibly depending on whether an indication of extended coverage is selected from the associated preamble partition, the WTRU may monitor for PO and/or PDCCH paging monitoring occasions starting from t0+δt, where δt is preconfigured, predefined or implicitly determined by the WTRU according to the gNB-WTRU RTT.

After backoff to the four-step RA, the PDCCH monitoring occasion for msgB, msgA retransmission, or Msg3 retransmission may be applied as an additional PDCCH monitoring occasion for Msg3 retransmission. These terms may be used interchangeably.

Although the 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 other features and elements. Furthermore, 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 a wired or wireless connection) and computer readable storage media. Examples of computer readable storage media include, but are not limited to, read Only Memory (ROM), random Access Memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and Digital Versatile Disks (DVDs). A processor associated with the software may be used to implement a radio frequency transceiver for use in a WTRU, terminal, base station, RNC, or any host computer.

Claims (20)

1. A method implemented in a Wireless Transmit Receive Unit (WTRU) for determining additional monitoring occasions for Physical Downlink Control Channel (PDCCH) transmissions, comprising:

receiving first configuration information for performing a first monitoring of a first PDCCH transmission for a first Msg3 retransmission;

Receiving second configuration information for performing a second monitoring of a second PDCCH transmission for a second Msg3 retransmission;

Transmitting a Physical Random Access Channel (PRACH) preamble;

Starting a monitoring window and monitoring PDCCH transmissions of a Random Access Response (RAR);

Receiving the RAR and stopping the monitoring window;

Transmitting at least one Msg3 based on the received RAR;

monitoring PDCCH transmissions based on a second monitoring of PDCCH transmissions for a second Msg3 retransmission;

Receiving a PDCCH transmission based on a second monitoring of a second PDCCH transmission, and

The third Msg3 is retransmitted based on the grant received in the PDCCH transmission.

2. The method of claim 1, wherein the second configuration information comprises an explicit indication to perform a second monitoring of PDCCH transmissions for a second Msg3 retransmission.

3. The method of claim 2, wherein the explicit indication is received via RAR, PDCCH order, or System Information Block (SIB) signaling.

4. A method according to any one of claims 1 to 3, wherein the validity time is associated with an explicit indication indicating a period of time during which the explicit indication is valid.

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

6. The method of any of claims 2 to 5, wherein the explicit indication comprises time period information for when an grant for an Msg3 retransmission is expected to be received.

7. The method of any of claims 1 to 6, further comprising monitoring PDCCH transmissions based on the first monitoring of the first PDCCH transmissions after the second monitoring of the second PDCCH transmissions, and transmitting a fourth Msg3 upon receipt of the second PDCCH transmissions.

8. The method of any of claims 1 to 7, wherein the condition to perform the second monitoring of PDCCH transmissions for blind Msg3 retransmissions is based on one or more values;

9. the method of claim 8, wherein the value comprises at least one of WTRU distance from a cell center, angle of satellite with respect to earth, or RSRP.

10. The method of claim 8 or 9, wherein the value is provided in system information, a Handover (HO) command, a Radio Resource Control (RRC) release message, or a RAR.

11. A method implemented in a Wireless Transmit Receive Unit (WTRU) for determining additional opportunities for monitoring Physical Downlink Control Channel (PDCCH) transmissions, comprising:

receiving first configuration information for performing a first monitoring of a first PDCCH transmission for a first Msg3 retransmission;

Receiving second configuration information for performing a second monitoring of a second PDCCH transmission for a second Msg3 retransmission;

starting a response window and monitoring PDCCH transmission of a random access response;

receiving a random access response and stopping a response window;

Transmitting at least one Msg3 based on the received random access response;

determining whether to perform a second monitoring of a second PDCCH transmission for retransmission based on an Msg3 repetition characteristic or an override condition, and

In response to meeting the Msg3 repetition characteristic or not meeting the override condition, a second PDCCH transmission for a second Msg3 retransmission grant is monitored.

12. The method of claim 11, wherein third configuration information is provided via Radio Resource Control (RRC) signaling, random access messages, medium access control elements (MAC CEs), paging messages, or Downlink Control Information (DCI), the third configuration information indicating whether the WTRU performs additional monitoring of blind Msg3 transmission grants based on Msg3 characteristics.

13. The method of claim 11 or 12, wherein the override condition is received via a Random Access Response (RAR), a message B (MSGB), or system information.

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

15. The method of any of claims 11-14, wherein whether the WTRU performs the second monitoring or the additional monitoring is based on a predetermined number of Msg3 retransmissions.

16. A Wireless Transmit Receive Unit (WTRU) configured to:

Receiving first configuration information for performing a first monitoring of a first physical downlink control channel (PDCCH transmission) for a first Msg3 retransmission;

Receiving second configuration information for performing a second monitoring of a second PDCCH transmission for a second Msg3 retransmission;

Transmitting a Physical Random Access Channel (PRACH) preamble;

Starting a monitoring window and monitoring PDCCH transmissions of a Random Access Response (RAR);

Receiving the RAR and stopping the monitoring window;

Transmitting at least one Msg3 based on the received RAR;

monitoring PDCCH transmissions based on a second monitoring of PDCCH transmissions for a second Msg3 retransmission;

Receiving a PDCCH transmission based on a second monitoring of a second PDCCH transmission, and

The third Msg3 is retransmitted based on the grant received in the PDCCH transmission.

17. The WTRU of claim 16 wherein the second configuration information includes an explicit indication to perform a second monitoring of PDCCH transmissions for a second Msg3 retransmission.

18. The WTRU of claim 17 wherein the explicit indication is received via RAR, PDCCH order, or System Information Block (SIB) signaling.

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

20. The WTRU of any one of claims 16 to 19, wherein the validity region is associated with an explicit indication indicating a region where the explicit indication is valid.