Multi-preamble physical random access channel indication

Abstract

The invention relates to a wireless transmit / receive unit (WTRU) and a method performed by the same. The WTRU comprises a processor configured to: receive RRC configuration information, the RRC configuration information indicating a first PRACH resource set associated with a first feature combination and a second PRACH resource set associated with a second feature combination; determining that the third feature combination is suitable for PRACH transmission; determining a configured feature priority associated with a first feature of a third feature combination, where the third feature combination includes a plurality of features, and the first feature has a highest configured feature priority among the plurality of features; determining to use one of the first set of PRACH resources or the second set of PRACH resources for PRACH transmission based on a configured feature priority associated with the first feature; and transmitting the PRACH transmission using the determined first set of PRACH resources or the determined second set of PRACH resources.

Description

[0001] This application is a divisional application of the Chinese invention patent application with an application date of August 3, 2022, application number 202280059907.8 (international application number PCT / US2022 / 039236), and invention name “Multi-preamble physical random access channel indication”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 228,903, filed on August 3, 2021, and U.S. Provisional Application Serial No. 63 / 249,940, filed on September 29, 2021, the contents of which are incorporated herein by reference. Background Art

[0004] Mobile communications using wireless communications continue to evolve. The fifth generation of mobile communications radio access technology (RAT) may be referred to as 5G New Radio (NR). Previous generation (legacy) mobile communications RAT may be, for example, fourth generation (4G) Long Term Evolution (LTE). Summary of the invention

[0005] Systems, methods, and means are described herein for indicating a feature combination associated with a wireless transmit / receive unit (WTRU) by determining a preamble set based on the feature combination associated with the WTRU.

[0006] The WTRU may receive configuration information indicating a random access channel opportunity (RO), for example, a first RO and a second RO. The ROs may be associated, and the configuration information may indicate the association of the ROs. The WTRU may be associated with a feature combination. The WTRU may determine a feature combination associated with the WTRU. The WTRU may determine a preamble set based on the feature combination associated with the WTRU. The preamble set may include a plurality of preamble subsets, for example, a first preamble subset and a second preamble subset. The first preamble subset may be associated with a first RO in the associated ROs. The second preamble subset may be associated with a second RO in the associated ROs. For example, in order to indicate to the network the feature combination associated with the WTRU, the WTRU may transmit a first preamble in a first preamble subset on a first RO of the associated ROs, and transmit a second preamble in a second preamble subset on a second RO of the associated ROs.

[0007] The WTRU may indicate a feature combination and / or information associated with the feature combination by transmitting a first preamble on a first RO and a second preamble on a second RO. For example, the first preamble transmitted on the first RO may indicate the feature combination, and the second preamble transmitted on the second RO may indicate additional information associated with the feature combination. The additional information associated with the feature combination may indicate one or more of the following: a feature of the feature combination, a distinction between features of the feature combination, or a randomized preamble selection of the WTRU that selected the feature combination.

[0008] The feature combination associated with the WTRU may include one or more features. For example, one of the one or more features may be indicated by a combination of a first preamble and a second preamble. In some examples, each of the first preamble and the second preamble may indicate the feature.

[0009] The configuration information indicating the associated RO may indicate one or more of the following: an association of a preamble set with a feature combination, an association of a first preamble subset with a first RO, and an association of a second preamble subset with a second RO. The WTRU may determine the preamble set based on the configuration information indicating the association of the preamble set with the feature combination and based on the feature combination associated with the WTRU. The WTRU may determine at least one of the first RO and the second RO based on the configuration information. For example, the second RO may be immediately adjacent to the first RO in time domain, or the second RO may be discontinuous with the first RO in time domain.

[0010] The WTRU may attempt to decode a random access response (RAR) using a random access radio network temporary identifier (RA-RNTI) associated with a preamble of a set of preambles or using a RA-RNTI associated with one or more of a first RO or a second RO. The WTRU may or may not receive a RAR for the transmission of the preamble. In an example, the WTRU may receive a RAR for a first preamble transmitted on a first RO and determine that a RAR for a second preamble transmitted on a second RO has not been received. Based on determining that a RAR for a second preamble transmitted on a second RO has not been received, the WTRU may transmit a third preamble of a second preamble subset on a third RO. The third preamble may be the same or different from the second preamble. In some examples, the WTRU may determine that the second preamble transmitted on the second RO indicates a feature of a feature combination, and based on determining that a RAR for the second preamble transmitted on the second RO has not been received, the WTRU may indicate the feature in a payload of the RAR grant.

[0011] A wireless transmit / receive unit (WTRU) comprises: a processor, the processor being configured to: receive radio resource control (RRC) configuration information indicating a first physical random access (PRACH) resource set associated with a first feature combination and a second PRACH resource set associated with a second feature combination; determine that a third feature combination is applicable to PRACH transmission; determine a configured feature priority associated with a first feature of the third feature combination, wherein the third feature combination includes multiple features and the first feature has the highest configured feature priority among the multiple features; determine to use one of the first PRACH resource set or the second PRACH resource set for PRACH transmission based on the configured feature priority associated with the first feature; and send PRACH transmission using the determined first PRACH resource set or the second PRACH resource set.

[0012] A method performed by a wireless transmit / receive unit (WTRU), comprising: receiving radio resource control (RRC) configuration information, the RRC configuration information indicating a first physical random access (PRACH) resource set associated with a first feature combination and a second PRACH resource set associated with a second feature combination; determining that a third feature combination is applicable to PRACH transmission; determining a configured feature priority associated with a first feature of the third feature combination, wherein the third feature combination includes multiple features and the first feature has a highest configured feature priority among the multiple features; based on the configured feature priority associated with the first feature, determining to use one of the first PRACH resource set or the second PRACH resource set for PRACH transmission; and sending the PRACH transmission using the determined first PRACH resource set or the second PRACH resource set.

[0013] A method includes: receiving configuration information, wherein the configuration information indicates a plurality of associated random access channel opportunities (ROs), wherein the plurality of associated ROs include a first RO and a second random RO; determining a set of preambles, wherein the set of preambles includes a first preamble subset associated with a first RO of the plurality of associated ROs, and includes a second preamble subset associated with a second RO of the plurality of associated ROs; transmitting a first preamble of the first preamble subset on a first RO of the plurality of associated ROs, and transmitting a second preamble of the second preamble subset on a second RO of the plurality of associated ROs; receiving a random access response (RAR) to the first preamble transmitted on the first RO; determining that a RAR to the second preamble transmitted on the second RO is not received; and transmitting a third preamble of the second preamble subset on a third RO based on determining that a RAR to the second preamble transmitted on the second RO is not received, wherein the third preamble is the same as the second preamble or different from the second preamble. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1A is a system diagram illustrating an exemplary communication system in which one or more disclosed embodiments may be implemented.

[0015] Figure 1B is shown in accordance with the embodiment which can be Figure 1A A system diagram of an exemplary wireless transmit / receive unit (WTRU) for use within a communication system is shown.

[0016] Figure 1C is shown in accordance with the embodiment which can be Figure 1A A system diagram of an exemplary radio access network (RAN) and an exemplary core network (CN) for use within a communication system is shown.

[0017] Figure 1D is shown in accordance with the embodiment which can be Figure 1A A system diagram of another exemplary RAN and another exemplary CN used within the communication system shown.

[0018] Figure 2 An example of exponential growth in the number of partitions indicating multiple features is shown.

[0019] Figure 3A An example of using a preamble set to indicate a feature combination is shown.

[0020] Figure 3 Examples of ROs and / or partitions are shown.

[0021] Figure 4A An example of a RO is shown.

[0022] Figure 4B An example of a RO is shown.

[0023] Figure 5 An example of allocating extended RA opportunities in the time domain in a multi-SSB cell is shown. DETAILED DESCRIPTION

[0024] Figure 1A1 is a schematic diagram illustrating an exemplary communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through sharing of system resources (including wireless bandwidth). For example, the communication system 100 may employ one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero tail unique word DFT spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multi-carrier (FBMC), etc.

[0025] like Figure 1A As shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110 and other networks 112, but it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d (any of which may be referred to as a “station” and / or “STA”) may be configured to transmit and / or receive wireless signals and may include user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated process chain environment), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any of the UEs 102a, 102b, 102c, and 102d may be interchangeably referred to as WTRUs.

[0026] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device that is configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNode B, a Home Node B, a Home eNode B, a gNB, an NR Node B, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0027] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies (which may be referred to as cells (not shown)). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrums. A cell may provide coverage of wireless services to a specific geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, a cell associated with the base station 114a may be divided into three sectors. Therefore, in one embodiment, the base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0028] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0029] More specifically, as noted above, the communication system 100 may be a multiple access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 115 / 116 / 117. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0030] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0031] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0032] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for example using dual connectivity (DC) principles. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNBs and gNBs).

[0033] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), GSM Enhanced Data Rates for Evolution (EDGE), GSM EDGE (GERAN), etc.

[0034] Figure 1A The base station 114b in the may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a local area, such as a business location, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or a femtocell. As Figure 1A As shown, base station 114b may have a direct connection to Internet 110. Therefore, base station 114b may not need to access Internet 110 via CN 106 / 115.

[0035] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, applications and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, delay requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not described in detail in the specification, the CN 106 / 115 may be configured to provide voice, data, applications and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. Figure 1AAlthough not shown in the figure, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0036] The CN 106 / 115 may also act as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) in the TCP / IP Internet protocol suite. The networks 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0037] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0038] Figure 1B is a system diagram illustrating an exemplary WTRU 102. Figure 1B As shown, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be appreciated that the WTRU 102 may include any subcombination of the foregoing elements while remaining consistent with an embodiment.

[0039] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functions that enable the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, but it is understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0040] The transmit / receive element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via an 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 one embodiment, the transmit / receive element 122 may be a transmitter / 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 RF and light signals. It should be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0041] Although the transmit / receive element 122 is Figure 1B 1 as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0042] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. For example, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0043] The processor 118 of the WTRU 102 may be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit) and may receive user input data therefrom. The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store data in any type of suitable memory, such as a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, 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 a home computer (not shown).

[0044] The processor 118 may receive power from the power source 134, and may be configured to distribute 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 cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0045] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or in lieu of the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by any suitable location-determination method while remaining consistent with an embodiment.

[0046] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, module, a frequency modulation (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, etc. Peripheral device 138 may include one or more sensors, which may be one or more of the following: a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0047] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference via hardware (e.g., a choke) or via signal processing performed by a processor (e.g., a separate processor (not shown) or via the processor 118). In one embodiment, the WRTU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0048] Figure 1C 1 is a system diagram showing the RAN 104 and the CN 106 in accordance with an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0049] The RAN 104 may include evolved Node-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of evolved Node-Bs while remaining consistent with an embodiment. The evolved Node-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the evolved Node-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the evolved Node-B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0050] Each of the evolved Node Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0051] Figure 1C The illustrated CN 106 may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements is depicted as being part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than a CN operator.

[0052] The MME 162 may be connected to each of the evolved Node-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0053] The SGW 164 may be connected to each of the evolved Node-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during inter-evolved Node-B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, and the like.

[0054] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0055] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may be in communication with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that 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 may include other wired and / or wireless networks owned and / or operated by other service providers.

[0056] Although the WTRU Figures 1A to 1D Although described as a wireless terminal, it is contemplated that in certain representative embodiments such a terminal may (eg, temporarily or permanently) employ a wired communications interface with a communications network.

[0057] In a representative embodiment, the other network 112 may be a WLAN.

[0058] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for a BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic to and / or carries traffic away from the BSS. Traffic originating from outside the BSS and leading to the STA may be reached by the AP and may be delivered to the STA. Traffic originating from the STA and leading 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 sent by the AP, for example, wherein the source STA may send traffic to the AP, and the AP may deliver the traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. Point-to-point traffic may be sent between the source and destination STAs (e.g., directly between them) using a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs (eg, 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.

[0059] When using the 802.11ac infrastructure operating mode or a similar operating mode, the AP may transmit a beacon on a fixed channel (such as a primary channel). The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a width dynamically set by signaling. The primary channel may be an operating channel of the BSS and may be used by the STA to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access / collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. For CSMA / CA, a STA (e.g., each STA) (including the AP) may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0060] High throughput (HT) STAs may communicate using a 40 MHz wide channel, for example, via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0061] Very high throughput (VHT) STA can support 20MHz, 40MHz, 80MHz and / or 160MHz wide channels. 40MHz and / or 80MHz channels can be formed by combining continuous 20MHz channels. A 160MHz channel can be formed by combining 8 continuous 20MHz channels, or by combining two non-continuous 80MHz channels (this can be called 80+80 configuration). For the 80+80 configuration, after channel coding, the data can pass through a segment parser that can divide the data into two streams. Each stream can be processed by inverse fast Fourier transform (IFFT) and time domain processing separately. These streams can be mapped to two 80MHz channels, and data can be transmitted by transmitting STA. At the receiver of the receiving STA, the above-mentioned operation for the 80+80 configuration can be reversed, and the combined data can be sent to the medium access control (MAC).

[0062] 802.11af and 802.11ah support operating modes below 1GHz. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah relative to those used in 802.11n and 802.11ac. 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support instrument type control / machine type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only support for) certain bandwidths and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain very long battery life).

[0063] WLAN systems that can support multiple channels and channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah include channels that can be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA (which supports the minimum bandwidth operating mode) from all STAs operating in the BSS. In the example of 802.11ah, for STAs (e.g., MTC-type devices) that support (e.g., only support) 1MHz mode, the primary channel may be 1MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because a STA (supporting only the 1MHz operating mode) is transmitting to the AP, the entire available frequency band may be considered busy even if most of the frequency bands remain idle and may be available.

[0064] In the United States, the available frequency band for 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

[0065] Figure 1D 1 is a system diagram showing the RAN 113 and the CN 115 in accordance with an embodiment. As noted above, the RAN 113 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0066] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 108b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a may, for example, use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum, while the remaining component carriers may be on a licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement a coordinated multi-point (CoMP) technique. For example, the WTRU 102a may receive coordinated transmissions from the gNB 180a and the gNB 180b (and / or the gNB 180c).

[0067] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable parameter sets. For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmit spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of varying or scalable lengths (e.g., containing different numbers of OFDM symbols and / or continuously varying absolute time lengths).

[0068] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c while also not accessing other RANs (e.g., such as the eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may use one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate or connect with the gNBs 180a, 180b, 180c while also communicating or connecting with other RANs, such as the evolved Node-Bs 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more evolved Node-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the evolved Node-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, 102c.

[0069] 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 slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards a user plane function (UPF) 184a, 184b, routing of control plane information towards an access and mobility management function (AMF) 182a, 182b, etc. Figure 1D As shown, gNBs 180a, 180b, and 180c may communicate with each other via an Xn interface.

[0070] Figure 1DThe illustrated CN 115 may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and possibly a data network (DN) 185a, 185b. While each of the foregoing elements is depicted as part of the CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than a CN operator.

[0071] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, support of network slicing (e.g., handling of different PDU sessions with different requirements), selecting a specific SMF 183a, 183b, management of registration areas, termination of NAS signaling, mobility management, etc. The AMF 182a, 182b may use network slicing to customize CN support for the WTRU 102a, 102b, 102c based on the type of services used by the WTRU 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced mobile broadband (eMBB) access, services for machine type communication (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0072] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b, and configure traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0073] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0074] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b via the UPF 184a, 184b via an N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0075] Given that Figures 1A to 1D as well as Figures 1A to 1D Corresponding to the description of the present invention, one or more or all of the functions described herein with reference to one or more of the following may be performed by one or more simulation devices (not shown): WTRU102a-d, base station 114a-b, evolved Node B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b and / or any other device described herein. The simulation device may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the simulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0076] The simulation device may be designed to implement one or more tests of other devices in a laboratory environment and / or an operator network environment. For example, the one or more simulation devices may perform one or more or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. The one or more simulation devices may perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device may be directly coupled to another device for testing purposes and / or may use over-the-air wireless communications to perform testing.

[0077] The one or more simulation devices may perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device may be used in a test scenario in a test lab and / or a non-deployed (e.g., testing) wired and / or wireless communication network to implement testing of one or more components. The one or more simulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuits (e.g., which may include one or more antennas) may be used by the simulation device to transmit and / or receive data.

[0078] Systems, methods, and means for advanced preamble partitioning and / or random access (RA) procedures are described herein.

[0079] A wireless transmit / receive unit (WTRU) may transmit a combination of preambles to indicate one or more of a feature, a feature combination, a capability combination, or a use case. A preamble may include a combination of two or more preamble transmissions. The WTRU may receive a radio resource control (RRC) or broadcast signaling to link a first random access channel opportunity (RO) and / or a first preamble index for a first preamble transmission to a second RO and / or preamble index for a second preamble transmission (e.g., an association between ROs of preambles). The RRC or broadcast signaling may indicate a partition of preambles for one or more of a feature, capability, feature combination, and / or use case. The WTRU may select a preamble combination (e.g., a preamble) to indicate one or more of a feature, capability, feature combination, and / or use case based on the configured preamble partition. The WTRU may select a preamble combination based on one or more of a feature, capability, feature combination, and / or use case to indicate which one initiated the RA process. During the RA procedure, if the WTRU has transmitted a preamble, the WTRU may monitor different random access responses (RARs) or MsgB formats. For example, the RAR (e.g., enhanced RAR) or MsgB format may contain the preamble index of the preamble or the preamble index of the first preamble transmission and the second preamble transmission. If the WTRU receives a RAR or MsgB corresponding to the first preamble but not the second preamble (e.g., a RAR or MsgB corresponding only to the first preamble), the WTRU may retransmit the second preamble. The payload of the RAR grant may also provide one or more indications herein.

[0080] The WTRU may receive configuration information, determine a preamble combination based on a feature / feature combination and the configuration information, wherein the preamble combination may include a first preamble and a second preamble; and transmit the preamble combination. The configuration information may indicate one or more preambles. The configuration information may indicate that a first RO of a first preamble is associated with a second RO of a second preamble. The configuration information may indicate that a first preamble index of a first preamble is associated with a second preamble index of a second preamble. The configuration information may indicate a partition associated with the preamble combination and a feature / feature combination corresponding to the partition. The WTRU may monitor a random access response (RAR) that includes a preamble index associated with the preamble combination or a preamble index associated with the first preamble and the second preamble. The WTRU may receive a RAR that includes a preamble index of the first preamble but does not include a preamble index of the second preamble, and transmit the second preamble.

[0081] Systems, methods, and means are described herein for indicating a feature combination associated with a wireless transmit / receive unit (WTRU) by determining a preamble set based on the feature combination associated with the WTRU.

[0082] The WTRU may receive configuration information indicating a random access channel opportunity (RO), for example, a first RO and a second RO. The ROs may be associated, and the configuration information may indicate the association of the ROs. The WTRU may be associated with a feature combination. The WTRU may determine a feature combination associated with the WTRU. The WTRU may determine a preamble set based on the feature combination associated with the WTRU. The preamble set may include a plurality of preamble subsets, for example, a first preamble subset and a second preamble subset. The first preamble subset may be associated with a first RO in the associated ROs. The second preamble subset may be associated with a second RO in the associated ROs. For example, in order to indicate to the network the feature combination associated with the WTRU, the WTRU may transmit a first preamble in a first preamble subset on a first RO of the associated ROs, and transmit a second preamble in a second preamble subset on a second RO of the associated ROs.

[0083] The WTRU may indicate a feature combination and / or information associated with the feature combination by transmitting a first preamble on a first RO and a second preamble on a second RO. For example, the first preamble transmitted on the first RO may indicate the feature combination, and the second preamble transmitted on the second RO may indicate additional information associated with the feature combination. The additional information associated with the feature combination may indicate one or more of the following: a feature of the feature combination, a distinction between features of the feature combination, or a randomized preamble selection of the WTRU that selected the feature combination.

[0084] The feature combination associated with the WTRU may include one or more features. For example, one of the one or more features may be indicated by a combination of a first preamble and a second preamble. In some examples, each of the first preamble and the second preamble may indicate the feature.

[0085] The configuration information indicating the associated RO may indicate one or more of the following: an association of a preamble set with a feature combination, an association of a first preamble subset with a first RO, and an association of a second preamble subset with a second RO. The WTRU may determine the preamble set based on the configuration information indicating the association of the preamble set with the feature combination and based on the feature combination associated with the WTRU. The WTRU may determine at least one of the first RO and the second RO based on the configuration information. For example, the second RO may be immediately adjacent to the first RO in time domain, or the second RO may be discontinuous with the first RO in time domain.

[0086] The WTRU may attempt to decode a random access response (RAR) using a random access radio network temporary identifier (RA-RNTI) associated with a preamble of a set of preambles or using a RA-RNTI associated with one or more of a first RO or a second RO. The WTRU may or may not receive a RAR for the transmission of the preamble. In an example, the WTRU may receive a RAR for a first preamble transmitted on a first RO and determine that a RAR for a second preamble transmitted on a second RO has not been received. Based on determining that a RAR for a second preamble transmitted on a second RO has not been received, the WTRU may transmit a third preamble of a second preamble subset on a third RO. The third preamble may be the same or different from the second preamble. In some examples, the WTRU may determine that the second preamble transmitted on the second RO indicates a feature of a feature combination, and based on determining that a RAR for the second preamble transmitted on the second RO has not been received, the WTRU may indicate the feature in a payload of the RAR grant.

[0087] PRACH resource partitions can be used to indicate one or more of best SSB, 2-step vs. 4-step RACH, and / or message 3 size (group A vs. B). Another PRACH partition can be used based on one or more of the following features: RedCap (e.g., indicating reduced-capability device types to the NW); SDT (e.g., differentiating RA procedures to support larger payload sizes for SDT); CovEnh (e.g., indicating coverage enhancement requirements for Msg3 repetitions); Slices (e.g., indicating high priority slices to the NW and / or implementing slice isolation for RACH). For example, some features may be supported simultaneously by the same device (e.g., an IIoT redcap device supporting SDT on a given slice). Partitions can be used to indicate a combination of one or more of the features herein. In some examples, 64 preambles may not be sufficient to support all of these feature indication combinations in a single RO. The number of RACH partitions can grow with the number of features (e.g., exponentially). For example, to indicate a combination of k features, 2 k The number of PRACH partitions may be increased further if the features are not introduced together (e.g., introduced in a consecutive release) and / or the legacy WTRU preamble selection is not changed. Figure 2An example of exponential growth in the number of partitions for indicating multiple features is shown. For (e.g., each) feature combination, the partitions can be further repeated by SSB and / or by group A / B sets. In the example, the overhead can be scaled by 2×N, where N is the number of SSBs multiplexed in the same RO in the cell. Assuming that P preambles (e.g., new preambles) are allocated to (e.g., each) feature partition in this example, the total number of preambles (e.g., new preambles) for indicating a feature combination (e.g., a new feature combination) using an ad-hoc method can be: Preamble Ad-hoc The number of new preambles required (e.g. Ad-hoc The number of) = 2 × N × P × 2 K For example, if N=6, k=4, P=8, the number of preambles is 1536 (24 ROs).

[0088] Physical random access channel (PRACH) resources may include one or more of the following: PRACH resources in frequency, PRACH opportunities or RACH opportunities (RO) (e.g., in time), preamble formats (e.g., based on one or more of total preamble duration, sequence length, guard duration and / or cyclic prefix length) and / or specific preamble sequences (e.g., preamble sequences used to transmit preambles in a random access procedure).

[0089] Small data may include uplink shared channel (UL-SCH) data (eg, non-common control channel (CCCH)) transmitted by the WTRU, for example, in non-connected mode.

[0090] In an example, MsgA may include a preamble and payload transmission on PRACH and physical uplink shared channel (PUSCH) resources, respectively, in a 2-step random access (RA) procedure (eg, the 2-step RA procedure defined in TS 38.321).

[0091] In an example, MsgB may include a downlink response to MsgA, which may be a successful random access response (RAR), a fallback RAR, or a fallback indication, for example, as defined in TS38.321.

[0092] In an example, the RO may be a RACH opportunity, for example, as defined in TS 38.321.

[0093] The preamble may include a specific combination (eg, a unique combination) of two or more preamble transmissions.

[0094] The term features and the term use case may be used interchangeably in one or more examples herein. A use case may correspond to an indication of one or more WTRU features or capabilities.

[0095] The attributes of the scheduling information (e.g., an uplink grant or a downlink allocation) may include at least one of (e.g., consist of): frequency allocation; aspects of time allocation, such as duration; priority; modulation and coding scheme; transport block size (TBS); number of spatial layers; number of transport blocks (TBs) to be carried; transmission configuration indication (TCI) status or SRS resource indicator (SRI); number of repetitions; and whether the grant is a configured grant type 1, type 2, or a dynamic grant.

[0096] An indication of downlink control information (DCI) may include at least one of (e.g., consist of): an explicit indication of a DCI field or a radio network identifier (RNTI) for masking a cyclic redundancy check (CRC) for a physical downlink control channel (PDCCH) (e.g., a PDCCH transmission); an implicit indication of one or more characteristics such as a DCI format, a DCI size, a control resource set (core set) or a search space, an aggregation level, and / or an identifier of a first control channel resource for the DCI (e.g., an index of a first control channel element (CCE)), wherein a mapping between characteristics and values ​​may be signaled by a radio resource control (RRC) or a media access control (MAC).

[0097] PRACH resource partitioning may be used (e.g., indicated by the WTRU to the network) to indicate a selection and / or preference for one or more of a feature, a priority, a synchronization signal and / or a physical broadcast channel block (SSB) or a TBS; the NW may determine the indication based on an index of the received preamble and / or the RO selected for the preamble transmission.

[0098] Another PRACH partition may be used. Another PRACH partition may be used in combination with one or more of the following features: RedCap, Small Data Transfer (SDT), CovEnh, Slicing. Depending on the capabilities of the WTRU, the WTRU may be configured to support different feature combinations herein. For example, an IoT WTRU may be a RedCap device that supports SDT transmissions on a given slice. Partitions may be used to indicate feature combinations. In some examples, 64 preambles may not be sufficient to support feature combinations (e.g., not sufficient to support all feature indication combinations in a single RO). The number of RACH partitions may grow with the number of feature combinations (e.g., exponentially). For example, to indicate a combination of k features, 2 kPRACH partitions. For example, it may be assumed that these features are introduced together without impacting the legacy WTRU preamble selection. For example, if the features are not introduced together (e.g., introduced in successive releases) and the legacy WTRU preamble selection is not changed, the number of partitions may be further increased. One or more examples herein may be used to increase capacity and / or efficiency without exponentially growing the number of partitions with the number of feature combinations.

[0099] Multiple PRACH transmissions may be used for use case indication.

[0100] The WTRU may transmit two preamble transmissions or a combination of multiple preamble transmissions to indicate one or more of a feature, capability, feature combination, capability combination, or feature and capability combination. For example, a first preamble transmission or a first preamble may indicate one or more of a first feature, a first feature combination, and / or a first capability, and / or a second preamble transmission or a second preamble may be used for randomization (e.g., randomized preamble selection of multiple WTRUs) and / or indication of one or more of a second feature, a second feature combination, and / or a second capability. The first preamble transmission or a first preamble may correspond to the intersection of multiple features (e.g., feature combinations), and / or the second preamble transmission or a second preamble may distinguish which of these features are, for example, by indicating the difference between these features. The combination of (e.g., each) of the first preamble and the second preamble may be associated with a corresponding feature, feature combination, or a set thereof. As Figure 3A As shown in the example in , the WTRU may use a set of preambles including preambles 54-57 on RO1 and preambles 0-15 on RO2 to indicate feature combination 1. Figure 3A In FIG. 1 , a set of preambles including preambles 56-59 on RO1 and preambles 16-31 on RO2 may be associated with feature combination 2. In some examples, more than one combination of a first preamble and a second preamble may be associated with one feature.

[0101] The preamble may be used for use case indication.

[0102] The preamble transmission may include one or more preambles, for example, a first preamble transmission and a second preamble transmission. The first preamble transmission may be, for example, a transmission of a first preamble in a first preamble subset based on a feature combination. The network (NW) may configure a subset of preambles and / or ROs (e.g., a first subset on some PRACH resources) for the first preamble transmission or the first preamble (possibly for each feature, use case, or feature combination). For example, based on the feature combination, the second preamble transmission may be a transmission of a second preamble in a second preamble subset. The NW may further configure a subset of preambles and / or ROs (e.g., a second subset on some PRACH resources) for the second preamble transmission or the second preamble (possibly for each feature, use case, or feature combination).

[0103] In an example, a set of preambles including a first subset and a second subset may be determined based on a combination of features. Figure 3A An example of using a preamble set to indicate a feature combination is shown. Figure 3A As shown, the WTRU may transmit a preamble (e.g., 2 preambles) in an associated RO to indicate an SSB and / or feature combination. Based on the SSB and / or feature combination that the WTRU wishes to indicate, the WTRU may determine the partition associated with the feature combination in RO1 and / or the associated RO2. The WTRU may select (e.g., randomly select) a preamble among the preambles in the associated partition of RO1 and transmit msg1. The WTRU may select (e.g., randomly select) a preamble among the preambles in the associated partition of RO2 and transmit msg1. The WTRU may monitor the RAR using the RA-RNTI of the preamble (e.g., each preamble) or using a combined RA-RNTI. For example, SSB B and / or feature combination 2 may be indicated. The WTRU may select (e.g., randomly select) a preamble for RO1 from 56-59 and a preamble for RO2 from 17-32. In Figure 3A In the example shown, there are 10 preambles per SSB in RO1 × 2 SSBs = 20 preambles, 20 preambles + 64 (16 × 4 combinations) preambles in RO2 = 84 preambles for all combinations of 2 SSBs. An alternative partitioning (e.g., traditional partitioning) requiring similar randomness with (4 + 16) preambles per combination may require 20 preambles per SSB per combination = 20 preambles × 2 SSBs × 4 combinations = 160 preambles (which would require at least one RO per SSB). Figure 3A The example in can increase the savings with more SSBs and more features and / or feature combinations.

[0104] Figure 3AThe preamble set in includes preambles with preamble indices 54-57 on RO1 and preambles with preamble indices 0-15 on another RO (e.g., RO2). RO1 and RO2 may be associated, for example, based on configuration information indicating the association of RO1 and RO2. The preamble set may be associated with feature combination 1. The WTRU may indicate feature combination 1 using a preamble set including preambles with preamble indices 54-57 on RO1 and preambles with preamble indices 0-15 on RO2. Figure 3A In the example shown, the preamble set including preambles 56-59 on RO1 and preambles 16-31 on RO2 can be associated with feature combination 2. The preamble set including preambles 58-61 on RO1 and preambles 32-47 on RO2 can be associated with feature combination 3. The preamble set including preambles 60-63 on RO1 and preambles 48-63 on RO2 can be associated with feature combination 4. Figure 3A In the example shown, on RO1, preambles 0-43 may use a traditional RACH allocation. Preambles 44-53 may or may not use a traditional RACH allocation, and, for example, preambles 44-53 may use a non-traditional RACH allocation. Preambles 54-63 may or may not use a traditional RACH allocation, and, for example, preambles 54-63 may use a non-traditional RACH allocation. Preambles 44-53 may be associated with SSB A, and preambles 54-63 may be associated with another SSB (e.g., SSB B). Preambles 54-63 may be used for characteristic indication of one SSB (e.g., SSB B).

[0105] The preamble may include a combination (e.g., a unique combination) of two or more preamble transmissions, such as a first preamble transmission and a second preamble transmission. Figure 3A As shown, the first preamble transmission may be, for example, a preamble from a subset of preambles with preamble indices 54-57 transmitted on RO1. The second preamble transmission may be, for example, a preamble from a subset of preambles with preamble indices 0-15 transmitted on RO2. In the example, the NW may create a space of unique preambles whose size is equal to: the number of preambles in the first subset × the number of preambles in the second subset. For example, on two ROs, each with 64 available preambles, the WTRU may select a preamble to indicate up to 64 2 The number of possible unique indications in the two transmissions of the preamble code = the number of possible preamble codes selected in the first RO × the number of possible preamble codes selected in the second RO.

[0106] The set of preambles from which the WTRU may select may include a subset of possible combinations of the first preamble and the second preamble. In one or more examples herein, one (e.g., each) such combination may be referred to as a valid preamble, and in one or more examples herein, the subset may be referred to as an active set. The WTRU may determine the active set using one of the following: sp An explicit list of combinations, where Nsp may be the size of the valid set; the WTRU may determine the valid set as a combination of a first subset of the first preamble and a second subset of the second preamble (e.g., all possible combinations). By extension, the WTRU may determine the valid set as the union of more than one such combination sets of multiple subsets (e.g., the union of more than one such combination sets of the first subset and the second subset). For example, the valid set may be the union of a first combination set including combinations of first preambles 32 to 47 and second preambles 50 to 57 and a second combination set including combinations of first preambles 48 to 63 and second preambles 58 to 63. One preamble subset may be configured per RO per feature combination. The network may configure the subset (i.e., whether to overlap it with another feature). In some examples, overlaps (e.g., overlaps of preamble subsets) may be avoided.

[0107] The WTRU may be configured with more than one preamble active set. The preamble active set may be configured based on use case, SSB, feature combination or one or more of the features and / or subset of PRACH resources.

[0108] The WTRU may transmit a first preamble of a preamble in a first set of ROs. The WTRU may transmit a second preamble of a preamble in a second set of ROs. The first set of ROs and the second set of ROs may be configured. For example, the first set of ROs and the second set of ROs may be defined such that, for example, an RO of the first set is immediately temporally subsequent to (e.g., immediately following) an RO of the second set, or an RO of the second set is immediately temporally subsequent to (e.g., immediately following) an RO of the first set. In some examples, the second RO of the second set and the first RO of the first set are not consecutive in the time domain.

[0109] Based on the feature or combination of features, one or more of the following parameters may be signaled (e.g., signaled to the WTRU) and / or determined (e.g., by the WTRU): for example, a preamble to be transmitted, a PRACH resource to be used for transmission, a partition on the RO, an SSB to be used for transmission, an RO to be used for transmission. The WTRU may receive signaling indicating parameters associated with an active set (e.g., parameters defining each active set of preambles or preambles). For example, this signaling may be part of an extended PRACH configuration information element in system information or dedicated signaling. This signaling may indicate a partition between preambles for single preamble transmissions (e.g., in legacy operation) and preambles for preamble transmissions. For example, the WTRU may receive parameters indicating a lowest possible value for a first preamble of a preamble (transmission) and a lowest possible value for a second preamble of a preamble (transmission). The WTRU may determine that the maximum preamble index for a single preamble transmission (e.g., according to legacy) in an RO corresponds to the lowest possible value associated with the preamble (transmission) in that RO.

[0110] A valid leading code may be identified by an index (e.g., a unique index). For example, the possible values ​​of the index may range from 0 to Nv-1. Nv may be the total number of valid leading codes across valid sets (e.g., all valid sets).

[0111] In some examples, the possible values ​​may range from 64 to 64+Nv-1 to reserve values ​​0 to 63 for the legacy preamble index. The index may be used to identify the preamble in the RAR. The WTRU may associate the index with the preamble, for example, using a formula or table.

[0112] Preambles can be concatenated. Preamble and / or RO mode can be configured.

[0113] To link preamble transmissions within a super-preamble (e.g., link a first preamble reception with a second preamble reception), the NW may configure the WTRU with a RO and / or a preamble selection mode, for example, using configuration information indicating an associated RO and a preamble selection mode. The WTRU may receive configuration information indicating an associated RO and a preamble selection mode. Preambles may be associated with PRACH resources. For example, a first preamble may be associated with a first PRACH resource and a second preamble may be associated with a second PRACH resource. The WTRU may select a PRACH resource for a preamble based on (e.g., as a function of) a PRACH resource selected for a different preamble in the super-preamble (e.g., a previous preamble). For example, Figure 3A As shown, the WTRU may select the PRACH resources on RO2 for the preamble with preamble index 9 based on the PRACH resources on RO1 for the preamble with preamble index 54.

[0114] For example, the ROs may be associated based on configuration information. The NW may configure the WTRU with an RO mode, for example, using configuration information indicating the associated ROs. For example, the associated ROs (e.g., RO pairs) may not be consecutive and / or may not intersect, so that the NW knows which feature combination is indicated. For example, a first preamble may be transmitted on partition A of RO x, and then a second preamble may be transmitted on partition B of RO y. Figure 3A As shown in the example of FIG. 1 , preamble 55 may be transmitted on partitions 54-57 of RO1 (e.g., by a WTRU), and then preamble 10 may be transmitted on partitions 0-15 of RO2. RO1 and RO2 may not be contiguous. The NW may identify a WTRU that transmits a first preamble on partition A of RO x and then a second preamble on partition B of RO y as a RedCap WTRU that performs small data, etc.

[0115] A first preamble may be selected and / or transmitted on a first RO. The NW may configure a subset of ROs applicable for a second preamble transmission based on (e.g., as a function of) one or more of the selected first preamble, the first RO, or the selected feature indicated in the first preamble transmission. The WTRU may receive configuration information indicating one or more of: an association of the first preamble and the second preamble, an association of the first preamble transmission and the second preamble transmission, an association of the first RO and the second RO, and / or an association of a first feature (e.g., a feature indicated in the first preamble transmission) and a second feature (e.g., a feature indicated in the second preamble transmission). The NW may configure the WTRU with a partition of preambles in a subsequent RO that is linked to one or more of the selected first preamble, the first RO, and / or the selected feature indicated in the first preamble transmission. The WTRU may receive configuration information indicating an association of a partition of preambles in a RO (eg, a second RO following a first RO) with one or more of a selected first preamble, a first RO, and / or a selected feature indicated in a first preamble transmission.

[0116] The WTRU may be configured (e.g., preconfigured) with an association between a feature and a first preamble and a second preamble and / or a RO. The WTRU may be configured with an association between a feature (e.g., a feature combination) and a set of preambles (e.g., a first preamble and a second preamble). The WTRU may be configured with an association between a feature and a RO. In an example, the WTRU may be preconfigured (e.g., by the NW) with an association between a feature and a first preamble and a second preamble or a RO so that the WTRU does not send all feature combinations. Certain combinations of features may not be allowed. Depending on the selected first preamble, the first RO and / or one or more of the features, the WTRU may transmit from a subset of the RO for the second preamble transmission. For example, the NW may not support a combination of slice WTRU capability and SDT capability. If the WTRU indicates to the NW that the WTRU is capable of supporting slices, the WTRU may not send the SDT capability during the second preamble transmission. In one or more examples herein, the first preamble and the first preamble transmission may be used interchangeably. In one or more examples herein, the second preamble and the second preamble transmission may be used interchangeably.

[0117] The WTRU may be configured with a priority for transmission of WTRU capabilities. In an example, in the case of transmitting a combination of WTRU capabilities, the WTRU may be configured (e.g., by the NW) with a priority for transmission of WTRU capabilities. For example, the WTRU may receive a priority indication from the NW that the RedCap capability has a higher priority than other capabilities (e.g., coverage enhancement or SDT). If the WTRU supports at least the RedCap capability, the WTRU may be configured to indicate the RedCap capability during the first preamble transmission (e.g., transmit RedCap WTRU). If the WTRU supports coverage enhancement functionality in addition to RedCap or slicing functionality, the WTRU may indicate the functionality during the second preamble transmission. Convenient configuration of Tx / Rx parameters for WTRU capabilities with higher priority may be achieved through prioritization and / or priority-based ordering (e.g., ordering of transmission) of WTRU capabilities.

[0118] The WTRU may be configured such that within a given RO, a first partition may be configured to indicate a first transmission (e.g., a first preamble transmission) and a second partition may be configured to indicate a second transmission (e.g., a second preamble transmission). For example, the first preamble transmission may be Figure 3A The partition 54-57 on RO1 in the figure is indicated, and the second preamble transmission can be indicated by Figure 3A Indicated by partitions 58-61 on RO1.

[0119] Figure 3 Examples of ROs and / or partitions are shown. Figure 3Preamble partitioning using preamble cross signature and SSB transmitted on two ROs (eg, RO1 and RO2, or RO3 and RO4) is shown.

[0120] The RO selection may be based on (eg, according to) a previously selected RO.

[0121] For example, depending on the features or use cases, the WTRU may be configured (e.g., through radio resource control (RRC) or broadcast signaling) with an association of ROs (e.g., between ROs of the advance preamble). The WTRU may be configured or specified to indicate some features (e.g., delay-sensitive features such as high priority slices) to the NW through a (e.g., single) preamble transmission. The WTRU may be configured or specified to indicate some features (e.g., other non-delay-critical features or use cases (e.g., SDT, Redcap, and CovEnh)) through two or more preamble transmissions.

[0122] The WTRU may be configured (e.g., via RRC or broadcast signaling) with a time (e.g., a minimum time and / or a maximum time) between preamble transmission opportunities within a preamble, and / or with a number of ROs between preamble transmissions of a preamble (e.g., a minimum and / or a maximum number of ROs). For example, the WTRU may select (e.g., randomly select) an RO for the next preamble transmission within the configured maximum time. The next preamble transmission may be a second preamble transmission. The WTRU may determine a different second subset (e.g., a second preamble subset, a second subset of ROs, and / or a second subset of other parameters herein) applicable to the second preamble transmission based on (e.g., according to) the selected RO and / or the time difference from the first preamble transmission.

[0123] Figure 4A An example of a RO is shown. Figure 4A A preamble space (eg, a preamble hopping pattern) for configuring a second preamble for transmitting a leading preamble is shown. Figure 4A The preamble space shown in may depend on the timing of the second RO (eg, depending on whether the transmission of the second preamble is on RO2, RO4, or RO6). Figure 4B An example of a RO is shown. Figure 4B A randomized hash function that can be used to determine the timing of the second RO ahead of the preamble is shown. Figure 4BAs shown, WTRU 1 may transmit a second preamble on RO6 after two randomized ROs (e.g., RO3 and RO5). In some examples, WTRU 2 may transmit a second preamble on RO6, a portion (e.g., an area) of which may be affected by the probability of conflict between features. For example, one or more parameters, variables, values, factors, or conditions may be configured for a feature, feature combination, and / or capability. As an example, for example, for a feature, feature combination, and / or capability, one or more of the following may be configured (e.g., by the NW), broadcast, or predefined: the number of preambles for each RO used for a first transmission (e.g., a first preamble transmission); the preamble start index for the first transmission; the set of ROs applicable to the first transmission, represented here as "Romask_1 st "; the number of preambles for each RO used for the second transmission (eg, the second preamble transmission); the preamble start index for the second transmission; the set of ROs applicable to the second transmission, represented here as "Romask_2 nd "; the maximum duration between the first preamble transmission and the second preamble transmission (or the maximum number of ROs), here represented as "maxPeriodbwPreambles"; the minimum duration between the first preamble transmission and the second preamble transmission (or the minimum number of ROs). The number of preambles for each RO used for the first transmission, the preamble start index for the first transmission, and Romask_1 st Can be used to indicate or define the preamble space "Preamble_subset_1 st "." The number of preambles for each RO used for the second transmission, the starting index of the preamble for the second transmission Romask_2 nd The preamble space "Preamble_subset_2 nd The WTRU may determine one or more of the parameters, variables, values, factors or conditions herein based on, for example, features, combinations of features and / or capabilities.

[0124] For example, the WTRU may be configured via RRC information to configure multiple preambles for each feature combination in a reserved area of ​​the preamble of a RO (e.g., a RO shared with a legacy WTRU). st It may or may not be shared with a legacy WTRU. For example, depending on the configuration, Romask_2 nd May be shared with legacy WTRU or not.

[0125] For example, after initiating the RA procedure to indicate a given feature combination, the WTRU may select from Preamble_subset_1 stAfter transmitting the first preamble, the WTRU may determine (e.g., randomly determine) the RO for the second preamble transmission. In the example, the WTRU may select the first preamble for transmission by Romask_2. nd The RO for the second preamble transmission may be selected (e.g., randomly) from the RO defined in the WTRU and within MaxPreiodbwPreambles from the instance in which the first preamble was transmitted (e.g., within maxPeriodbwPreambles starting after the transmission of the first preamble). The WTRU may start a timer to transmit the second preamble after transmitting the first preamble, and the WTRU may transmit the second preamble after the timer expires (e.g., using the next valid preamble). In an example, the value of the timer may be randomly selected (e.g., initially between [0 and maxPeriodbwPreambles]).

[0126] The WTRU may be configured to determine a second preamble index.

[0127] The WTRU may determine Preamble_subset_2 based on (e.g., according to) one or more of the following: nd The preamble index within: the RO selected for the second transmission (e.g., the second preamble transmission), the RO selected for the first transmission (e.g., the first preamble transmission), the preamble index selected for the first transmission, and / or the period between the first transmission and the second transmission (and / or the number of ROs). In an example, the WTRU may use a formula to determine the preamble index for the second transmission.

[0128] Here is an example formula: Preamble index range for second transmission "range" = {preamble start index for second transmission + offset value, preamble start index for second transmission + offset value + number of preambles for each RO for second transmission}. The offset value (Offset) used in the formula may be an offset value that can be used to shift the preamble start range according to the selected RO. For example, the offset value may be as follows: offset value = (RO index for second transmission - RO index for first transmission - 1) × shift, or offset value = mod\{RO index for second transmission, RO index for first transmission} × shift, where "shift" is an integer number of preambles configured, predefined or broadcasted by the NW, for example. If the range exceeds preamble index 63, the range may be cyclically shifted and / or wrapped between 0 and 63 to include preambles {0, max(range)-63}. Although one or more examples herein are described in terms of two preambles, two preamble transmissions, or two ROs, these examples are also applicable to more than two preambles, more than two preamble transmissions, or more than two ROs.

[0129] RAR / MsgB monitoring can be performed.

[0130] Depending on channel conditions or collisions, the NW may be able to successfully receive and / or decode the first preamble, e.g., without successfully receiving or decoding the second preamble, or the NW may be able to successfully receive and / or decode the second preamble, e.g., without successfully receiving or decoding the first preamble.

[0131] In case of a preamble collision (e.g., a preamble collision of only the second preamble or only the first preamble), the NW may be able to address the colliding WTRUs (e.g., uniquely address both colliding WTRUs), for example, by signaling a preamble index in the RAR / MsgB, or by signaling two RARs corresponding to a first index (e.g., a preamble index for the first transmission or an RO index for the first transmission) and a second index (e.g., a preamble index for the second transmission or an RO index for the second transmission). The WTRU may monitor or attempt to decode the PDCCH transmission for reception of the RAR or MsgB after transmission of the second preamble (e.g., instead of after transmission of the first preamble) and / or after transmission of the first preamble. In an example, if the transmission of the first preamble is followed by the second preamble or the transmission of the second preamble, the WTRU may skip PDCCH monitoring of the RAN / MsgB after transmission of the first preamble. If the WTRU has transmitted a preamble, the WTRU may monitor or attempt to decode a different RAR or MsgB format. For example, the different RAR or MsgB format may include an enhanced RAR or MsgB format, where the enhanced RAR or MsgB format may contain a preamble index or an index of the first preamble and the second preamble.

[0132] If the WTRU receives a RAR corresponding to one or more of the preamble index of the first transmission, the preamble index of the second transmission, or the preamble index of the preamble, the WTRU may stop the RAR or MsgB window (e.g., the configured RAR or MsgB window) and / or consider the reception of Msg2 / B to be successful. For example, the WTRU may start a monitoring window (e.g., a RAR or MsgB window) at the first symbol of the earliest core set (CORESET) where the WTRU is configured to receive PDCCH transmissions for RAR / MsgB reception. The first symbol of the earliest core set where the WTRU is configured to receive PDCCH transmissions for RAR / MsgB reception may be at least one symbol after the last symbol of the last RO used to transmit the preamble (e.g., the last symbol of the second RO in this document).

[0133] The WTRU may monitor the RA-RNTI corresponding to the second RO, monitor the RA-RNTI corresponding to the first RO, monitor the RA-RNTI corresponding to both the second RO and the first RO, or monitor the RA-RNTI corresponding to the second RO and the RA-RNTI corresponding to the first RO. In one or more examples herein, the term "monitoring" may be used interchangeably with the term "attempting to decode". The WTRU may be predefined or configured to monitor the RA-RNTI corresponding to the second RO, monitor the RA-RNTI corresponding to the first RO, monitor the RA-RNTI corresponding to both the second RO and the first RO, or monitor the RA-RNTI corresponding to the second RO and the RA-RNTI corresponding to the first RO. The WTRU may monitor the RA-RNTI corresponding to a preamble transmission associated with a preamble (e.g., a first preamble transmission or a second preamble transmission) and / or the RA-RNTI corresponding to the preamble, or monitor multiple RA-RNTIs corresponding to respective preamble transmissions associated with the preamble (e.g., two RA-RNTIs, a first RA-RNTI corresponding to the first preamble transmission, and a second RA-RNTI corresponding to the second preamble transmission). The WTRU may monitor a preamble RA-RNTI that is calculated taking into account one or more of: resource allocation in the time domain for one of the ROs associated with the preamble (e.g., the first RO or the second RO), resource allocation in the frequency domain for one of the ROs associated with the preamble (e.g., the first RO or the second RO), resource allocation in the time domain for multiple ROs of the ROs associated with the preamble (e.g., the first RO and the second RO), and resource allocation in the frequency domain for multiple ROs of the ROs associated with the preamble (e.g., the first RO and the second RO). In an example, the WTRU may monitor a RA-RNTI that is equal to the sum of RA-RNTIs associated with corresponding ROs of some or all ROs associated with the preamble (e.g., the sum of the RA-RNTI associated with the first RO and the RA-RNTI associated with the second RO). In some examples, the RA-RNTI associated with the preamble transmitted on 2 ROs can be calculated as follows: RA-RNTI=1+s_id_1 st RO+14×t_id_1 st RO+14×80×f_id_1 st RO+s_id_2 nd RO+14×t_id_2 nd RO+14×80×f_id_1 ndRO+14×80×8×ul_carrier_idEquation 1

[0134] Equation 1 may be applicable to RA-RNTIs associated with preambles transmitted on more than 2 ROs.

[0135] The WTRU may monitor, for example, a slot format indication (SFI) index in a DCI scheduling Msg2 / B. The WTRU may receive one or more of an SFI index corresponding to an RO (e.g., a first RO or a second RO associated with a preamble), an SFI index corresponding to multiple ROs (e.g., a first RO and a second RO associated with a preamble). If the SFI is signaled as part of the DCI, the WTRU may consider that the RAR reception is successful, for example, if it corresponds to the SFI of the first RO, the second RO, or both ROs. The WTRU may monitor different or specific DCI indications depending on whether the WTRU has transmitted one preamble, whether the WTRU has transmitted more than one (e.g., two) preambles, and / or whether the selected RO is associated with different ROs.

[0136] In Msg2 / B, there may be an acknowledgement from the NW that the NW has received multiple transmissions (e.g., the first transmission and the second transmission associated with the advance preamble), or an indication portion requesting a transmission or retransmission loss (e.g., an indication associated with the first preamble).

[0137] In an example, if the WTRU does not receive a RAR or Msg2 / B, the WTRU may retransmit the first preamble transmission and the second preamble transmission.

[0138] The transmission of a preamble (e.g., a first preamble or a second preamble associated with a preamble) may or may not be successful. For example, if the WTRU receives a RAR or MsgB with a random access preamble identifier / identification (ID) (RAPID) that corresponds to a preamble associated with a preamble (e.g., the first preamble or the second preamble) or corresponds to the preamble, the WTRU may assume that the transmission of msg1 has been successful. If, for example, a RAR or Msg2 / B corresponding to the first preamble is not received within the RAR window, the WTRU may retransmit the first preamble or a second preamble in the set of preambles that includes the first preamble. For example, if the WTRU receives a RAR or MsgB corresponding to the first preamble (e.g., only corresponding to the first preamble) and / or the WTRU does not receive a RAR for the second preamble, the WTRU may retransmit the second preamble. If the WTRU receives a RAR or MsgB corresponding to the first preamble (eg, only corresponding to the first preamble) and / or the WTRU does not receive a RAR for the second preamble, the WTRU may transmit a third preamble from the subset of preambles that includes the second preamble.

[0139] If multiple failures occur, or a time period (e.g., based on a timer) expires, the WTRU may fall back to legacy RACH. The WTRU may indicate the use case of the feature in the Msg3 / A payload. In an example, if the WTRU receives a RAR or MsgB corresponding to a first preamble (e.g., corresponding only to the first preamble) and / or the WTRU does not receive a RAR for a second preamble, the WTRU may indicate a second feature (e.g., a second feature of the feature combination) in the payload of the RAR grant. For example, if the transmission is successful, the second preamble may indicate the second feature.

[0140] RA-RNTI conflicts can be reduced.

[0141] A WTRU may use separate ROs with the same RA-RNTI (e.g., with the same slot index and frequency offset values). For example, two WTRUs (i.e., one legacy WTRU and another WTRU supporting PRACH partitioning / indication) may use two separate ROs with the same RA-RNTI. When the number of feature combinations is at a certain value (e.g., a large value), the feature combinations may not be separated on different ROs with different RA-RNTI values. For example, in some cases, it may not be possible to separate feature combinations on different ROs with different RA-RNTI values.

[0142] An explicit indication may be added in the Msg2 / MsgB / RAR to distinguish the PDCCH monitoring associated with the WTRU from the legacy WTRU (e.g., to distinguish the PDCCH monitoring of the WTRU from the PDCCH monitoring of the legacy WTRU). If the WTRU does not receive the explicit indication, the WTRU may discard the RAR and / or continue to monitor the PDCCH for another Msg2 / MsgB / / RAR with the RA-RNTI (e.g., the same RA-RNTI) and containing an indication (e.g., an explicit indication).

[0143] The WTRU may add an offset value to the RA-RNTI formula to distinguish the PDCCH monitoring associated with the WTRU from the legacy WTRUs (e.g., to distinguish the PDCCH monitoring of the WTRU from the PDCCH monitoring of the legacy WTRUs). The WTRU may scramble the RA-RNTI with another value (e.g., another value depending on the selected PRACH resource).

[0144] The use case indication may not be based on RACH.

[0145] Subsequent indications may be used for feature combinations.

[0146] The WTRU may indicate support for and / or request use of a feature set via a subsequent indication (e.g., after a preamble and / or initial transmission). A feature set may include (e.g., consist of) one feature or a combination of features. Whether the WTRU may indicate a feature set via a subsequent indication may be determined by the NW (e.g., restricted) and / or configured, for example, via RRC signaling or via explicit indication (e.g., in system information). The complete feature set may be indicated (e.g., uniquely) via a subsequent indication, or may be combined with one or more features indicated via other means (e.g., preamble transmission, capability signaling, or device type indication). The subsequent indication configuration may indicate whether the subsequent indication provides all or part of the feature set, and / or may indicate how these other features (e.g., preamble transmission and / or device type indication) have been indicated.

[0147] The subsequent indication may include information about and / or provide an indication of one or more of the following: support for a feature or WTRU capability; a request for use of a feature, or a request to terminate use of a feature; whether the WTRU feature list is a complete list or a partial list of supported features; whether the subsequent indication is to be combined with another indication and / or with which other indication (e.g., preamble transmission) the subsequent indication is to be combined; whether the feature is mandatory and / or necessary for accessing the NW (e.g., coverage enhancement); whether the subsequent indication includes a modification to the previous indication (e.g., adding or removing supported features).

[0148] For example, the supported feature set may be indicated via a list. The WTRU may include some or all of the features supported in a subsequent indication, such as all of the features supported in the subsequent indication or only those features that the WTRU intends to use. The list may indicate (e.g., alternatively indicate) a list of features that the WTRU intends to enable or disable. For example, a dedicated information element (IE) or bit may be indicated (e.g., separate from the feature list) whether the WTRU expects to enable or disable a feature or feature list. In some examples, the subsequent indication may represent an index value. The index value may point to a specific entry in a table (e.g., a table containing feature set combinations and / or a table containing possible feature set combinations). In some examples, feature set combinations and feature combinations may be used interchangeably. The table may be provided via one or more of the following ways, such as provided in system information, provided via RRC signaling, or provided via DCI. In some examples, the feature list may be included as a bitmap, where supported and / or requested features may be classified as "1", while disabled and / or unsupported features may be classified as "0".

[0149] The WTRU may transmit subsequent indications and / or communicate support for and / or request to use feature set information, for example, via one or more of the following: additional bits in the RACH preamble; PUSCH transmission (e.g., using Msg3 and / or MsgA payload); PUCCH transmission (e.g., via UCI); MAC CE; RRC signaling, for example, via capability report or dedicated feature set IE; device type indication; NAS signaling; scheduling request (SR).

[0150] The WTRU may select the resource, timing or method for providing the subsequent indication based on one or more of the following, for example: semi-static configuration (e.g., provided via RRC signaling); dynamic indication (e.g., based on an explicit request from the NW via DCI, RAR or system information); the connection state of the WTRU (e.g., a WTRU in an RRC connected state may transmit the subsequent indication, for example, via MAC CE, PUSCH, SR or RRC signaling; a WTRU in an RRC idle / inactive state may transmit the subsequent indication, for example, via one or more of a dedicated preamble, a Msg3 UL grant, an RRC message or msgA PUSCH resources); whether the feature is necessary for RA (e.g., a WTRU requiring coverage enhancement may send at least the feature indication via, for example, a preamble transmission); whether support for the feature affects the network decision for access control (e.g., the WTRU may select resources to communicate that the WTRU is a RedCap WTRU before the RA procedure is completed so that the WTRU can be rejected via an RRC reject message); the stage of the RA procedure (e.g., if the WTRU has received a RAR, the WTRU may select resources to communicate that the WTRU is a RedCap WTRU before the RA procedure is completed so that the WTRU can be rejected via an RRC reject message); The subsequent indication may be included on the PUSCH resource, or if the WTRU has received Msg4, the subsequent indication may be included in the capability signaling); the number or quantity of previous subsequent feature indication transmission attempts; the number of features supported by the WTRU; whether the indication is an update to the previous indication.

[0151] Based on the transmission of a subsequent indication (e.g., when the subsequent indication is transmitted), the WTRU may assume that the feature is (de)activated and / or use the feature in the symbol immediately following the last symbol in the subsequent indication transmission, or at some offset value K after the last symbol in the subsequent indication transmission. In some examples, the WTRU may determine that the feature is active based on receiving an explicit acknowledgement from the NW (e.g., only assume that the feature is active when the explicit acknowledgement is received from the NW). The WTRU may determine the explicit acknowledgement (e.g., assume the explicit acknowledgement), for example, via one or more of the following: HARQ ACK; RAR; Msg4 / MsgB; PDCCH transmission of a DCI assigned to the WTRU; PDSCH transmission; scheduling information; bandwidth part (BWP) switching indication; RRC message.

[0152] A combination of features may be indicated. A set of valid feature combinations may be provided to the WTRU from which a feature set combination is indicated. The set of valid feature combinations may be indicated via a table or list having entries including (e.g., consisting of) valid or invalid feature combinations, or via a mapping rule. One or more of the table, list, or mapping rule may be signaled to the WTRU via, for example, one or more of: system information, RACH configuration, RRC signaling, or DCI. The configuration may also include an applicable bandwidth (e.g., BWP) over which the PRACH resource is valid for a feature or feature combination (e.g., for each feature or each feature combination) and / or whether the resource is on a normal UL (NUL), a supplemental UL (SUL), or both. For example, one or more of the system information, RACH configuration, RRC signaling, or DCI (or one or more of the table, list, or mapping rule) may include a BWP over which the PRACH resource is valid for the feature or feature combination, and / or may indicate whether the resource is on the NUL, SUL, or both.

[0153] Based on the transmission of an invalid feature combination set (e.g., when an invalid set of feature combinations is transmitted), one or more of the following may occur: the WTRU may be denied access to the NW (e.g., via an RRC reject message), retransmit the feature set with a valid combination, fall back to 4-step RACH, retransmit the preamble combination and / or perform a RA.

[0154] In some examples, the WTRU may group features according to the stage in the connection establishment process at which they are used (e.g., required). For example, the WTRU may group features required to perform RA (e.g., Coverage Enhancement, RedCap).

[0155] The WTRU may not have valid PRACH resources to indicate the feature combination for which the RA was initiated. If the WTRU does not have valid PRACH resources to indicate the feature combination for which the RA was initiated, the WTRU may perform one or more of the following: the WTRU may multiplex the feature or feature combination for which the RACH was initiated in the payload of Msg3 or MsgA; the WTRU may select PRACH resources configured for features that are part of the desired feature combination, for example even if the feature is combined with another undesired feature; the WTRU may select PRACH resources configured to indicate a subset of features from the feature combination for which the RA was triggered; for example, after the RA is successfully completed, the WTRU may trigger an SR on the SR configuration associated with the feature to indicate; the WTRU may transmit an indication on the PUCCH associated with the feature to be indicated (for example, after the RA is successfully completed); the WTRU may switch its active UL and / or DL ​​BWP to another BWP on which the PRACH resources indicating the feature or feature combination are configured.

[0156] The WTRU may select the PRACH resources configured to indicate a subset of features from the feature combination for which the RA is triggered. For example, when initiating a RA for a feature combination, the WTRU may be configured or predefined with some priority rules to determine which PRACH resource to select, and the available PRACH resources (e.g., each available PRACH resource) in the active BWP is configured for the feature subset of the feature combination. For example, the WTRU may be configured with PRACH resources for feature A, feature B, and feature C, and a RA may be initiated to indicate a combination of feature A and feature B; if feature B takes precedence over feature A, the WTRU may select PRACH resources for feature B. For example, if a RA is initiated for SDT and Redcap indication, the WTRU may prioritize PRACH resources configured for SDT. If a RA is initiated for CovEnh (e.g., Msg3 or Msg1 repetition) and Redcap indication, the WTRU may prioritize PRACH resources configured for CovEnh. If a RA is initiated for SDT and CovEnh indication, the WTRU may prioritize PRACH resources configured for SDT. An example of priorities (e.g., priority rules) between features may be: priority of small data > priority of slicing > priority of reduction capability > priority of coverage enhancement). An example of priorities (e.g., priority rules) between features may be: priority of small data > priority of reduction capability > priority of slicing > priority of coverage enhancement.

[0157] For example, after a number of retransmissions (or transmissions) or after an elapsed time (eg, expiration of a timer since the initial preamble transmission), the WTRU may switch to a different PRACH resource associated with a different feature initiating a RA within the feature combination.

[0158] For example, if the WTRU selects a PRACH resource that is configured to indicate a subset of features from the feature combination for which the RA was triggered, the WTRU may include a subsequent indication to indicate the features that were missing in the preamble indication. For example, the WTRU may select a PRACH resource associated with Redcap, but later indicate a high priority slice or slice index in a subsequent transmission (e.g., on PUSCH, another PRACH, or PUCCH).

[0159] For example, depending on the active BWP, the WTRU may consider a subset of feature combinations valid. The WTRU may configure PRACH resources for feature combinations on a subset of BWPs and may, for example, consider the feature combination valid for the BWP (eg, only valid for the subset of BWPs).

[0160] The WTRU may switch BWPs. For example, the WTRU may switch its active BWP (e.g., UL BWP and / or DL ​​BWP) to an initial BWP or a BWP (e.g., indicated by a BWP index) for which a feature combination is considered valid (or configured) at the time of RA initiation, for example based on one or more of the following: if the active BWP (e.g., active UL BWP) does not contain valid PRACH resources to perform a RACH indication (e.g., a RACH indication of a feature that initiated the RACH); if the initial BWP is configured with PRACH resources partitioned with the feature combination (or a subset thereof) for which the RA was triggered.

[0161] The WTRU may indicate a feature or feature combination for RA procedures initiated in a subset of modes (e.g., idle, inactive, and / or connected states). In the connected state, the WTRU may use PRACH resources associated with a feature or feature combination for a specific type or any type of RA (e.g., RA triggered by expiration of a timing alignment timer (TAT) or RA triggered by a scheduling request (RA-SR) or beam failure recovery (BFR)). In some examples, the WTRU may exclude (or not select) PRACH resources associated with a first feature or a first feature combination for RA procedures triggered in the connected mode (e.g., RA triggered by TAT expiration or RA-SR or BFR). The WTRU may use PRACH resources associated with a second feature or feature combination. In the connected state, the WTRU may use PRACH resources associated with a feature or feature combination (e.g., if valid or available in an active BWP) for a RA-SR procedure initiated by an SR triggered by the arrival of data from one or more of a data radio bearer (DRB), a logical channel (LCH), or a logical channel group (LCG) associated with the feature or feature combination. The WTRU may select a valid PRACH resource or any valid PRACH resource for transmission associated with the RA-SR procedure (eg, if there are no valid PRACH resources for the feature or feature combination in the active BWP in the connected state).

[0162] For example, in the inactive state, if a RA is issued indicating a feature combination that includes SDT, the WTRU may multiplex in the small data payload indications of other features that are not explicitly configured for PRACH indications in the RA-SDT resources (e.g., one or more of a coverage enhancement indication, a high priority slice, a slice index, or a reduced capability indication in the payload).

[0163] In some configurations, the WTRU may have PRACH partitions for some features or feature combinations only on 2-step RA resources, only on 4-step RA resources, or on both. The WTRU may select the RA type (e.g., 2-step or 4-step RA), for example, based on the feature or feature combination to be indicated. For example, if the PRACH resources used to indicate the feature or feature combination are not configured for 2-step RA on an active BWP, the WTRU may select 4-step RA to indicate the feature combination (e.g., even if the RSRP is above the RA type selection threshold or the measured RSRP is not compared to the threshold configured for 2-step RA type selection). In some examples, if the PRACH resources used to indicate the feature or feature combination are not configured for 4-step RA on an active BWP, the WTRU may select 2-step RA to indicate the feature combination (e.g., even if the RSRP is less than the RA type selection threshold or the measured RSRP is not compared to the threshold configured for 2-step RA type selection). For example, after a number of retransmissions (or elapsed time), the WTRU may change the RA type for the preamble retransmission or transmission. In an example, the WTRU may fall back to 4-step RA.

[0164] In some configurations, for example, the WTRU may have PRACH partitions for some features or feature combinations only on Group A preambles, only on Group B preambles, or on both. The WTRU may select a preamble group (e.g., Group A or Group B), for example, depending on whether the feature or feature combination to be indicated is configured. For example, if no PRACH resources are configured for Group B preambles to indicate a feature or feature combination, then the WTRU may use Group A to indicate the feature combination even if one or more conditions (e.g., legacy conditions) for selecting Group B are met (e.g., if the path loss is above a Group B threshold and / or the expected TBS is greater than a threshold). If no PRACH resources are configured for Group A preambles to indicate a feature or feature combination, then the WTRU may use Group B to indicate the feature combination even if one or more conditions (e.g., legacy conditions) for selecting Group A are met (e.g., if the path loss is above a Group B threshold and / or the expected TBS is less than a threshold). For example, after a number of retransmissions or transmissions (or elapsed time), the WTRU may change the preamble group for a preamble retransmission.

[0165] The following may be an example of allocating extended RA opportunities in the time domain in a multi-SSB cell. Figure 5 An example of allocating extended RA opportunities in the time domain in a multi-SSB cell is shown. Figure 5An example of an association (e.g., a predefined association) between the timing of a second RO of a preamble and the timing of a first RO is shown in FIG. 1 , where the association is configured for each SSB set. For example, in order to transmit a second preamble within an associated time period associated with an SSB burst, the WTRU may be configured with an extended RO. For a conventional RO configured with an association for a subset of SSBs, the WTRU may be configured with an associated second extended RO before mapping the next associated time period for the same subset of SSBs. This is shown in one or more of the figures herein (e.g., FIG. 1 ). Figure 5 ). The WTRU may be configured via RRC or broadcast signaling with an RO mask associated with which ROs are extended ROs for the second transmission and which SSB subset is associated with the extended RO (e.g., each extended RO). It may be assumed (e.g., by the WTRU) that the extended RO is after an integer number of associated time periods and / or SSB mapping periods. The extended RO may be configured to frequency multiplex a subset of SSBs multiplexed in the same first RO in the same mapping period. For example, the first RO and the second RO may be in the same timeslot, or in a timeslot in which the SSBs are applicable / broadcast, with a configured or predefined time gap between the two ROs to allow separation in the transmission power domain. For example, the WTRU may be configured with an association between multiple ROs (e.g., two ROs) in a manner similar to the association configured between PRACH and PUSCH opportunities in a Type 2 RA procedure.

[0166] The following may be an example of analysis of PRACH overhead between PRACH partitions using a single preamble transmission and / or multiple transmissions. If two preamble transmissions may be linked to the same WTRU, the WTRU may indicate one of 642 unique indications (e.g., with two ROs, each with 64 available preambles).

[0167] It may be assumed that multiple ROs (e.g., 2 ROs) are associated (e.g., using linkage similar to that defined in 2-step RA for PRACH and PUSCH opportunities). The WTRU may transmit multiple (e.g., two) preamble transmissions to indicate a feature combination. For example, a first preamble transmission may indicate a feature combination, SSB, and msg3 group A vs. B; and a second preamble transmission may be used for randomization between WTRUs selecting the same feature combination, e.g., to reduce the probability of preamble collisions. This is illustrated in one or more of the figures herein (e.g., Figure 3 ). In some examples, the NW may configure the first preamble transmission such that the first preamble transmission may correspond to an intersection of multiple features, and / or the second preamble distinguishes which of these features.

[0168] A PRACH capacity gain may be achieved. For example, in the simplest minimum, a PRACH capacity gain may be due to the fact that the feature combination partition in the second RO does not need to be repeated for each SSB and each msg3 group set because the spatial separation between WTRUs is exploited.

[0169] If multiple (e.g., two) WTRUs simultaneously select the same SSB and the same feature combination in the first RO (e.g., preamble collision in the first RO), the WTRUs may be distinguished or separated by the second preamble transmission if the WTRUs randomly select different preamble indices in the second RO. If multiple (e.g., two) WTRUs simultaneously select the same SSB but different feature combinations, the WTRUs may be distinguished or separated by the second preamble transmission by the feature partition in the second RO in the preamble index field. If multiple (e.g., two) WTRUs select different SSBs but the same feature combination in the first RO, the WTRUs (e.g., two WTRUs) may further randomize their preamble selection in the second RO, and if the WTRUs (e.g., two WTRUs) select different preambles in the second RO, the NW may address the WTRUs (e.g., two WTRUs) by sending multiple (e.g., two) RARs. For example, according to the usual RA procedure, if the WTRU receives a RAR with a RAPID corresponding to the first preamble index or the second preamble index, the WTRU may consider that the msg1 transmission is successful.

[0170] In an example where a single preamble is allocated for each SSB of (e.g., each) feature combination in a first RO and P preambles are allocated for each SSB of the feature combination in a second RO, the PRACH overhead associated with the feature indication of the two preamble transmissions may be estimated as: 2-preamble tx (e.g., the number of new preambles required 2-preamble tx )=2×N×2 K +P×2 K Taking N=6 SSBs as an example; K=4 features (SDT, RedCap, slice and cover); P=8 preambles, the number of preambles (e.g., the required number) using the ad-hoc method is 1536 (24 ROs), while the number of preambles (e.g., the required number) using the 2-preamble tx method is 320 (5 ROs), thus corresponding to a 79% reduction in PRACH overhead.

[0171] In addition to indicating this feature, one potential benefit is to increase the coverage and reliability of msg1 by transmitting multiple (e.g., 2) preambles. In an example, the NW (e.g., gNB receiver) may combine the two transmissions to increase the coverage of msg1, for example, as long as they are from the same root sequence and the gNB does not detect a preamble collision (e.g., even if the selected preambles have different indices). For example, when the WTRU is in poor coverage, the NW may not be able to correctly detect the first preamble alone, but the first preamble may be combined with the reception of the second preamble for better estimation and / or detection.

[0172] Although the above features and elements are described in particular combinations, each feature or element may be used alone without the other features and elements of the preferred embodiments, or in various combinations with or without the other features and elements.

[0173] Although the implementation described herein may consider 3GPP specific protocols, it should be understood that the implementation described herein is not limited to such scenarios and may be applicable to other wireless systems. For example, although the solution described herein considers LTE, LTE-A, New Radio (NR) or 5G specific protocols, it should be understood that the solution described herein is not limited to such scenarios and may be applicable to other wireless systems.

[0174] The processes described above may be implemented in a computer program, software, and / or firmware incorporated in a computer-readable medium for execution by a computer and / or a processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted via a wired or wireless connection) and / or computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media (such as, but not limited to, built-in hard disks and removable disks), magneto-optical media, and optical media (such as compact disk (CD)-ROM disks and / or digital versatile disks (DVDs)). A processor associated with the software may be used to implement a radio frequency transceiver for a WTRU, terminal, base station, RNC, and / or any host computer.

Claims

1. A wireless transmit / receive unit (WTRU), the WTRU comprising: A processor, the processor being configured to: receiving radio resource control (RRC) configuration information indicating a first set of physical random access (PRACH) resources associated with a first feature combination and a second set of PRACH resources associated with a second feature combination; Determining that the third feature combination is applicable to PRACH transmission; determining a configured feature priority associated with a first feature of the third feature combination, wherein the third feature combination includes a plurality of features and the first feature has a highest configured feature priority among the plurality of features; determining, based on the configured feature priority associated with the first feature, to use one of the first PRACH resource set or the second PRACH resource set for the PRACH transmission; as well as The PRACH transmission is sent using the determined first PRACH resource set or the second PRACH resource set.

2. The WTRU of claim 1 , wherein: The determining to use one of the first set of PRACH resources or the second set of PRACH resources for the PRACH transmission is further based on the first feature being in the first feature combination or the second feature combination.

3. The WTRU of claim 1 , wherein: The processor is further configured to determine that the first feature is in the first feature combination, wherein, based on the configured feature priority associated with the first feature and the determination that the first feature is in the first feature combination, the first PRACH resource set is determined to be used for the PRACH transmission, and the PRACH transmission is sent using the first PRACH resource set.

4. The WTRU of claim 3, wherein: The first PRACH resource set indicates a preamble and a RACH opportunity associated with the preamble.

5. The WTRU of claim 1 , wherein: The third feature combination is different from the first feature combination and the second feature combination, wherein the first feature is in the first feature combination but not in the second feature combination, and wherein it is determined to use the first PRACH resource set for the PRACH transmission.

6. The WTRU of claim 1 , wherein: The processor is further configured to determine that the third feature combination is for initiating a random access procedure including sending the PRACH transmission, and wherein the determining that the third feature combination is applicable to the PRACH transmission is based on the determining that the third feature combination is for initiating the random access procedure.

7. The WTRU of claim 1 , wherein: The first feature corresponds to a capability of the WTRU, and wherein the capability of the WTRU is one of: RedCap; small data transfer (SDT); coverage enhancement or Msg3 repetition; or slicing.

8. The WTRU according to claim 1, wherein the multiple features include small data transmission (SDT), slicing, RedCap and coverage enhancement, wherein the first feature is SDT, and wherein the feature priority of the configuration associated with SDT is higher than the feature priority of the configuration associated with slicing, the feature priority of the configuration associated with slicing is higher than the feature priority of the configuration associated with RedCap, and the feature priority of the configuration associated with RedCap is higher than the feature priority of the configuration associated with coverage enhancement.

9. The WTRU of claim 1 , wherein: The processor is further configured to receive radio resource control (RRC) configuration information, and wherein the configured feature priority associated with the first feature is determined based on the RRC configuration information.

10. The WTRU of claim 9, wherein: The RRC configuration information indicates a corresponding configured feature priority of each of the plurality of features.

11. The WTRU of claim 1 , wherein: The processor is further configured to receive system information, wherein the system information indicates a corresponding configured feature priority for each of the plurality of features, and wherein the configured feature priority associated with the first feature is determined based on the system information.

12. A method performed by a wireless transmit / receive unit (WTRU), the method comprising: receiving radio resource control (RRC) configuration information indicating a first set of physical random access (PRACH) resources associated with a first feature combination and a second set of PRACH resources associated with a second feature combination; Determining that the third feature combination is applicable to PRACH transmission; determining a configured feature priority associated with a first feature of the third feature combination, wherein the third feature combination includes a plurality of features and the first feature has a highest configured feature priority among the plurality of features; determining, based on the configured feature priority associated with the first feature, to use one of the first PRACH resource set or the second PRACH resource set for the PRACH transmission; as well as The PRACH transmission is sent using the determined first PRACH resource set or the second PRACH resource set.

13. The method according to claim 12, wherein: The determining to use one of the first set of PRACH resources or the second set of PRACH resources for the PRACH transmission is further based on the first feature being in the first feature combination or the second feature combination.

14. The method of claim 12, further comprising determining that the first feature is in the first feature combination, wherein: Based on the configured feature priority associated with the first feature and the determining that the first feature is in the first feature combination, determining that the first PRACH resource set is used for the PRACH transmission, and sending the PRACH transmission using the first PRACH resource set.

15. The method according to claim 14, wherein: The first PRACH resource set indicates a preamble and a RACH opportunity associated with the preamble.

16. A method comprising: receiving configuration information, wherein the configuration information indicates a plurality of associated random access channel opportunities (ROs), wherein the plurality of associated ROs include a first RO and a second random RO; determining a set of preambles, wherein the set of preambles includes a first subset of preambles associated with the first of the plurality of associated ROs and includes a second subset of preambles associated with the second of the plurality of associated ROs; transmitting a first preamble of the first subset of preambles on the first RO of the plurality of associated ROs, and transmitting a second preamble of the second subset of preambles on the second RO of the plurality of associated ROs; receiving a random access response (RAR) to the first preamble transmitted on the first RO; determining that a RAR for the second preamble transmitted on the second RO is not received; as well as Based on the determining that the RAR for the second preamble transmitted on the second RO is not received, a third preamble of the second preamble subset is transmitted on a third RO, wherein the third preamble is the same as the second preamble or different from the second preamble.

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