CN117917172A

CN117917172A - Multi-preamble physical random access channel indication

Info

Publication number: CN117917172A
Application number: CN202280059907.8A
Authority: CN
Inventors: 法里斯·阿尔法罕; 保罗·马里内尔; 狄伦·沃茨; 长谷川文大; 久保庆一
Original assignee: InterDigital Patent Holdings Inc
Current assignee: InterDigital Patent Holdings Inc
Priority date: 2021-08-03
Filing date: 2022-08-03
Publication date: 2024-04-19

Abstract

A wireless transmit/receive unit (WTRU) may receive configuration information indicating associated random access channel opportunities (ROs) (e.g., first RO and second RO). The WTRU may determine a combination of features associated with the WTRU. The WTRU may determine the set of preambles based on a combination of features associated with the WTRU. The preamble set may include a plurality of preamble subsets, e.g., a first preamble subset associated with a first RO of an associated RO and a second preamble subset associated with a second RO of the associated RO. The WTRU may transmit a first preamble in a first preamble subset on a first RO of the plurality of associated ROs and a second preamble in a second preamble subset on a second RO of the plurality of associated ROs.

Description

Multi-preamble physical random access channel indication

Cross Reference to Related Applications

The present application claims the benefit of U.S. provisional application serial No. 63/228,903 filed on month 83 2021 and U.S. provisional application serial No. 63/249,940 filed on month 9 29 2021, the contents of which are incorporated herein by reference.

Background

Mobile communications using wireless communications continue to evolve. The fifth generation mobile communication Radio Access Technology (RAT) may be referred to as 5G new air interface (NR). The previous generation (legacy) mobile communication RAT may be, for example, fourth generation (4G) Long Term Evolution (LTE).

Disclosure of Invention

Systems, methods, and instrumentalities are described herein to indicate 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.

The WTRU may receive configuration information indicating random access channel occasions (ROs) (e.g., first ROs and second ROs). 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 combination of features associated with the WTRU. The WTRU may determine the set of preambles based on a combination of features associated with the WTRU. The preamble set may include a plurality of preamble subsets, e.g., a first preamble subset and a second preamble subset. The first subset of preambles may be associated with a first RO of the associated ROs. The second subset of preambles may be associated with a second RO of the associated ROs. For example, to indicate to the network a combination of features associated with the WTRU, the WTRU may transmit a first preamble in a first subset of preambles on a first RO of the associated RO and a second preamble in a second subset of preambles on a second RO of the associated RO.

The WTRU may indicate the feature combination and/or information associated with the feature combination by transmitting a first preamble on the first RO and a second preamble on the second RO. For example, a first preamble transmitted on a first RO may indicate a feature combination, and a second preamble transmitted on a 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: the features of the feature combination, the distinction between features of the feature combination, or the randomized preamble selection of the WTRU selecting the feature combination.

The combination of features 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 the first preamble and the second preamble. In some examples, each of the first preamble and the second preamble may indicate the feature.

The configuration information indicating the associated RO may indicate one or more of: association of a preamble set with a feature combination, association of a first preamble subset with a first RO, association of a second preamble subset with a second RO. The WTRU may determine the preamble set based on configuration information indicating an 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 in time with the first RO in the time domain, or the second RO may be discontinuous with the first RO in the time domain.

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 the preamble set or using RA-RNTIs associated with one or more of the first RO or the second RO. The WTRU may or may not receive the RAR of the transmission of the preamble. In an example, the WTRU may receive an RAR for a first preamble transmitted on a first RO and determine that an RAR for a second preamble transmitted on a second RO has not been received. Based on determining that an RAR for the second preamble transmitted on the second RO has not been received, the WTRU may transmit a third preamble of the second preamble subset on a third RO. The third preamble may be the same as or different from the second preamble. In some examples, the WTRU may determine that the second preamble transmitted on the second RO indicates a characteristic of the combination of characteristics, and based on determining that the RAR for the second preamble transmitted on the second RO was not received, the WTRU may indicate the characteristic in a payload of the RAR grant.

Drawings

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

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

Fig. 1C is a system diagram illustrating an exemplary Radio Access Network (RAN) and an exemplary Core Network (CN) that may be used within the communication system shown in fig. 1A, according to an embodiment.

Fig. 1D is a system diagram illustrating another exemplary RAN and another exemplary CN that may be used in the communication system shown in fig. 1A, according to an embodiment.

FIG. 2 illustrates an example of an exponential increase in the number of partitions used to indicate a plurality of features.

Fig. 3A illustrates an example of using a preamble set to indicate feature combinations.

Fig. 3 shows an example of ROs and/or partitions.

Fig. 4A shows an example of RO.

Fig. 4B shows an example of RO.

Fig. 5 shows an example of allocation of extended RA occasions in the time domain in a multi SSB cell.

Detailed Description

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

As shown in fig. 1A, the communication system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, RANs 104/113, CNs 106/115, public Switched Telephone Networks (PSTN) 108, the internet 110, and other networks 112, although 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. As an example, the WTRUs 102a, 102b, 102c, 102d (any of which may be referred to as a "station" and/or a "STA") may be configured to transmit and/or receive wireless signals and may include User Equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular telephones, personal Digital Assistants (PDAs), smartphones, laptop computers, netbooks, personal computers, wireless sensors, hot spot or Mi-Fi devices, internet of things (IoT) devices, watches or other wearable devices, head Mounted Displays (HMDs), vehicles, drones, medical devices and applications (e.g., tele-surgery), industrial devices and applications (e.g., robots and/or other wireless devices operating in an industrial and/or automated processing chain environment), consumer electronic devices, devices operating on commercial and/or industrial wireless networks, and the like. Any of the UEs 102a, 102b, 102c, and 102d may be interchangeably referred to as WTRUs.

Communication system 100 may also include base station 114a and/or base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106/115, the internet 110, and/or the other network 112. By way of example, the base stations 114a, 114B may be Base Transceiver Stations (BTSs), node bs, evolved node bs, home evolved node bs, gnbs, NR node bs, site controllers, access Points (APs), wireless routers, and the like. Although the base stations 114a, 114b are each depicted as a single element, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements.

Base station 114a may be part of RAN 104/113 that may also include other base stations and/or network elements (not shown), such as Base Station Controllers (BSCs), radio Network Controllers (RNCs), relay nodes, and the like. Base station 114a and/or base station 114b may be configured to transmit and/or receive wireless signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage of wireless services to a particular 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 base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each sector of a 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 a cell. For example, beamforming may be used to transmit and/or receive signals in a desired spatial direction.

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

More specifically, as noted above, communication system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, or the like. For example, a 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 interfaces 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).

In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as evolved UMTS terrestrial radio access (E-UTRA), which may use Long Term Evolution (LTE) and/or advanced LTE (LTE-a) and/or advanced LTE Pro (LTE-a Pro) to establish the air interface 116.

In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access that may use a new air interface (NR) to establish the air interface 116.

In embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, e.g., using a Dual Connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and/or transmissions sent to/from multiple types of base stations (e.g., enbs and gnbs).

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 1X, CDMA EV-DO, tentative standard 2000 (IS-2000), tentative standard 95 (IS-95), tentative standard 856 (IS-856), global system for mobile communications (GSM), enhanced data rates for GSM evolution (EDGE), GSM EDGE (GERAN), and the like.

The base station 114B in fig. 1A may be, for example, a wireless router, home node B, home evolved node B, or access point, and may utilize any suitable RAT to facilitate wireless connections in local areas such as business, home, vehicle, campus, industrial facility, air corridor (e.g., for use by drones), road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a Wireless Local Area Network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a Wireless Personal Area Network (WPAN). In yet another embodiment, the base station 114b and the wtrus 102c, 102d may utilize A cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A pro, NR, etc.) to establish A pico cell or femto cell. As shown in fig. 1A, the base station 114b may have a direct connection with the internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106/115.

The RANs 104/113 may communicate with the CNs 106/115, which may be any type of network configured to provide voice, data, application, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102 d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, delay requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106/115 may provide call control, billing services, mobile location based services, prepaid calls, internet connections, video distribution, etc., and/or perform advanced security functions such as user authentication. Although not shown in fig. 1A, it should be appreciated that the RANs 104/113 and/or CNs 106/115 may communicate directly or indirectly with other RANs that employ the same RAT as the RANs 104/113 or a different RAT. For example, in addition to being connected to the RAN 104/113 that may utilize NR radio technology, the CN 106/115 may also communicate with another RAN (not shown) employing GSM, UMTS, CDMA 2000, wiMAX, E-UTRA, or WiFi radio technology.

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.PSTN 108 may include circuit-switched telephone networks that provide Plain Old Telephone Services (POTS). The internet 110 may include a global system for interconnecting computer networks and devices using common communication protocols, such as Transmission Control Protocol (TCP), user Datagram Protocol (UDP), and/or Internet Protocol (IP) in the TCP/IP internet protocol suite. Network 112 may include wired and/or wireless communication networks owned and/or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RANs 104/113 or a different RAT.

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

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

The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a Digital Signal Processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, application Specific Integrated Circuits (ASICs), field Programmable Gate Arrays (FPGAs) circuits, any other type of Integrated Circuit (IC), a state machine, or the like. 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 a transceiver 120, which may be coupled to a transmit/receive element 122. Although fig. 1B depicts the processor 118 and the transceiver 120 as separate components, it should be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

The transmit/receive element 122 may be configured to transmit signals to and receive signals from a base station (e.g., base station 114 a) over the air interface 116. For example, in one embodiment, the transmit/receive element 122 may be an antenna configured to transmit and/or receive RF signals. In one embodiment, the transmit/receive element 122 may be an emitter/detector configured to emit 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 optical signals. It should be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals.

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

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

The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker/microphone 124, a keypad 126, and/or a display/touchpad 128, such as a Liquid Crystal Display (LCD) display unit or an Organic Light Emitting Diode (OLED) display unit. The processor 118 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128. Further, the processor 118 may access information from and store data in any type of suitable memory, such as the non-removable memory 130 and/or the removable memory 132. The non-removable memory 130 may include Random Access Memory (RAM), read Only Memory (ROM), a hard disk, or any other type of memory storage device. 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 never physically locate memory access information on the WTRU 102, such as on a server or home computer (not shown), and store the data in that memory.

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 battery packs (e.g., nickel cadmium (NiCd), nickel zinc (NiZn), nickel metal hydride (NiMH), lithium ion (Li-ion), etc.), solar cells, fuel cells, and the like.

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

The processor 118 may also be coupled to other peripheral devices 138, which may include one or more software modules and/or hardware modules that provide additional features, functionality, and/or wired or wireless connections. For example, the number of the cells to be processed, peripheral devices 138 may include accelerometers, electronic compasses, satellite transceivers, digital cameras (for photographs and/or video), universal Serial Bus (USB) ports, vibrating devices, television transceivers, hands-free headsets, wireless communications devices, and the like,Modules, frequency Modulation (FM) radio units, digital music players, media players, video game player modules, internet browsers, virtual reality and/or augmented reality (VR/AR) devices, activity trackers, and the like. The peripheral device 138 may include one or more sensors, which may be one or more of the following: gyroscopes, accelerometers, hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors; a geographic position sensor; altimeters, light sensors, touch sensors, magnetometers, barometers, gesture sensors, biometric sensors, and/or humidity sensors.

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

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

RAN 104 may include enode bs 160a, 160B, 160c, but it should be understood that RAN 104 may include any number of enode bs while remaining consistent with an embodiment. The enode bs 160a, 160B, 160c may each include one or more transceivers to communicate 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 enode B160 a may use multiple antennas to transmit wireless signals to the WTRU 102a and/or to receive wireless signals from the WTRU 102a, for example.

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

The CN 106 shown in fig. 1C may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) gateway (or PGW) 166. While each of the foregoing elements are depicted as part of the CN 106, it should be understood that any of these elements may be owned and/or operated by an entity other than the CN operator.

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 function as a control node. For example, the MME 162 may be responsible for authenticating the user of the WTRUs 102a, 102b, 102c, bearer activation/deactivation, selecting a particular serving gateway during initial attach of the WTRUs 102a, 102b, 102c, and the like. MME 162 may provide control plane functionality for switching between RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and/or WCDMA.

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

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

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

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

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

A WLAN in an infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) for the BSS and one or more Stations (STAs) associated with the AP. The AP may have access or interface to a Distribution System (DS) or another type of wired/wireless network that carries traffic to and/or from the BSS. Traffic originating outside the BSS and directed to the STA may arrive through 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 respective destination. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may pass the traffic to the destination STA. Traffic between STAs within a BSS may be considered and/or referred to as point-to-point traffic. Point-to-point traffic may be sent between (e.g., directly between) the source and destination STAs using 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 (e.g., all STAs) within or using the IBSS may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad hoc" communication mode.

When using the 802.11ac infrastructure mode of operation or similar modes of operation, the AP may transmit beacons on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20MHz wide bandwidth) or a width dynamically set by signaling. The primary channel may be an operating channel of the BSS and may be used by STAs 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, STAs (e.g., each STA), including the AP, may listen to the primary channel. If the primary channel is listened to/detected by a particular STA and/or determined to be busy, the particular STA may backoff. One STA (e.g., only one station) may transmit at any given time in a given BSS.

High Throughput (HT) STAs may communicate using 40MHz wide channels, for example, via a combination of a primary 20MHz channel with an adjacent or non-adjacent 20MHz channel to form a 40MHz wide channel.

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

The 802.11af and 802.11ah support modes of operation below 1 GHz. Channel operating bandwidth and carrier are reduced in 802.11af and 802.11ah relative to those used in 802.11n and 802.11 ac. The 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the television white space (TVWS) spectrum, and the 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to representative embodiments, 802.11ah may support meter type control/machine type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including supporting (e.g., supporting only) certain bandwidths and/or limited bandwidths. MTC devices may include batteries with battery lives above a threshold (e.g., to maintain very long battery lives).

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

The available frequency band for 802.11ah in the united states is 902MHz to 928MHz. In 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.

Fig. 1D is a system diagram illustrating a RAN 113 and a CN 115 according to an embodiment. As noted above, RAN 113 may employ NR radio technology to communicate with WTRUs 102a, 102b, 102c over an air interface 116. RAN 113 may also communicate with CN 115.

RAN 113 may include gnbs 180a, 180b, 180c, but it should be understood that RAN 113 may include any number of gnbs while remaining consistent with an embodiment. Each of the gnbs 180a, 180b, 180c may include one or more transceivers to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. In one implementation, the gnbs 180a, 180b, 180c may implement MIMO technology. For example, gnbs 180a, 108b may utilize beamforming to transmit signals to and/or receive signals from gnbs 180a, 180b, 180 c. Thus, the gNB 180a may use multiple antennas to transmit wireless signals to and/or receive wireless signals from the WTRU 102a, for example. In an embodiment, the gnbs 180a, 180b, 180c may implement carrier aggregation techniques. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on the unlicensed spectrum while the remaining component carriers may be on the licensed spectrum. In embodiments, the gnbs 180a, 180b, 180c may implement coordinated multipoint (CoMP) techniques. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and/or gNB 180 c).

The WTRUs 102a, 102b, 102c may communicate with the gnbs 180a, 180b, 180c using transmissions associated with the scalable parameter sets. For example, the OFDM symbol interval and/or OFDM subcarrier interval may vary from one transmission to another, from one cell to another, and/or from one portion of the wireless transmission spectrum to another. The WTRUs 102a, 102b, 102c may communicate with the gnbs 180a, 180b, 180c using various or scalable length subframes or Transmission Time Intervals (TTIs) (e.g., including different numbers of OFDM symbols and/or continuously varying absolute time lengths).

The gnbs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in an independent configuration and/or in a non-independent configuration. In a 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 enode bs 160a, 160B, 160 c). In an independent configuration, the WTRUs 102a, 102b, 102c may use one or more of the gnbs 180a, 180b, 180c as mobility anchor points. In an independent configuration, the WTRUs 102a, 102b, 102c may use signals in unlicensed frequency bands to communicate with the gnbs 180a, 180b, 180 c. In a non-standalone configuration, the WTRUs 102a, 102B, 102c may communicate or connect with the gnbs 180a, 180B, 180c, while also communicating or connecting with other RANs (such as the enode bs 160a, 160B, 160 c). For example, the WTRUs 102a, 102B, 102c may implement DC principles to communicate with one or more gnbs 180a, 180B, 180c and one or more enodebs 160a, 160B, 160c substantially simultaneously. In a non-standalone configuration, the enode bs 160a, 160B, 160c may serve as mobility anchors for the WTRUs 102a, 102B, 102c, and the gnbs 180a, 180B, 180c may provide additional coverage and/or throughput for serving the WTRUs 102a, 102B, 102 c.

Each of the gnbs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and/or DL, support of network slices, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards User Plane Functions (UPFs) 184a, 184b, routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, and so on. As shown in fig. 1D, gnbs 180a, 180b, 180c may communicate with each other through an Xn interface.

The CN 115 shown in fig. 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While each of the foregoing elements are depicted as part of the CN 115, it should be understood that any of these elements may be owned and/or operated by an entity other than the CN operator.

AMFs 182a, 182b may be connected to one or more of gNB 180a, 180b, 180c in RAN 113 via an N2 interface and may function as a control node. For example, the AMFs 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slices (e.g., handling of different PDU sessions with different requirements), selection of a particular SMF 183a, 183b, management of registration areas, termination of NAS signaling, mobility management, etc. The AMFs 182a, 182b may use network slices to customize CN support for the WTRUs 102a, 102b, 102c based on the type of service used by the WTRUs 102a, 102b, 102 c. For example, different network slices may be established for different use cases, such as services relying on ultra-high reliability low latency (URLLC) access, services relying on enhanced mobile broadband (eMBB) access, services for Machine Type Communication (MTC) access, and so on. AMF 162 may provide control plane functionality for switching between RAN 113 and other RANs (not shown) employing other radio technologies, such as LTE, LTE-A, LTE-a Pro, and/or non-3 GPP access technologies, such as WiFi.

The SMFs 183a, 183b may be connected to AMFs 182a, 182b in the CN 115 via an N11 interface. The SMFs 183a, 183b may also be connected to UPFs 184a, 184b in the CN 115 via an N4 interface. SMFs 183a, 183b may select and control UPFs 184a, 184b and configure traffic routing through UPFs 184a, 184b. The SMFs 183a, 183b may perform other functions such as managing and assigning UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, etc. The PDU session type may be IP-based, non-IP-based, ethernet-based, etc.

UPFs 184a, 184b may be connected to one or more of the gnbs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to a packet-switched network, such as the internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. UPFs 184, 184b may perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multi-host PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, and the like.

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 connect to the local Data Networks (DNs) 185a, 185b through the UPFs 184a, 184b through an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

In view of fig. 1A-1D and the corresponding descriptions of fig. 1A-1D, 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 emulation devices (not shown): the WTRUs 102a-d, base stations 114a-B, evolved node bs 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMFs 182a-B, UPFs 184a-B, SMFs 183a-B, DN 185a-B, and/or any other devices described herein. The emulated device may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation device may be used to test other devices and/or analog network and/or WTRU functions.

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

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

Systems, methods, and instrumentalities are described herein for advanced preamble partitioning and/or Random Access (RA) procedures.

A wireless transmit/receive unit (WTRU) may transmit a combination of preambles to indicate one or more of a feature, a combination of features, a combination of capabilities, or a use case. The preamble may include a combination of two or more preamble transmissions. The WTRU may receive Radio Resource Control (RRC) or broadcast signaling to link a first random access channel occasion (RO) and/or a first preamble index for a first preamble transmission to a second RO and/or a preamble index (e.g., an association between ROs of a preamble) for a second preamble transmission. RRC or broadcast signaling may indicate the partitioning of the preamble for one or more of the features, capabilities, feature combinations, and/or use cases. The WTRU may select a preamble combination (e.g., a preamble) to indicate one or more of a feature, a capability, a combination of features, and/or a use case based on the configured preamble partition. The WTRU may select a preamble combination based on one or more of the features, capabilities, feature combinations, and/or use cases to indicate which initiated the RA procedure. During the RA procedure, if the WTRU has transmitted a preamble, the WTRU may monitor a different Random Access Response (RAR) or MsgB format. For example, the RAR (e.g., enhanced RAR) or MsgB format may contain a preamble index of a preamble or a preamble index of a first preamble transmission and a second preamble transmission. The WTRU may retransmit the second preamble if the WTRU receives a RAR or MsgB (e.g., a RAR or MsgB corresponding to the first preamble only) corresponding to the first preamble but not the second preamble. The payload of the RAR grant may also provide one or more indications herein.

The WTRU may receive configuration information, determine a preamble combination based on the feature/feature combination and the configuration information, wherein the preamble combination may include a first preamble and a second preamble; and transmitting the preamble combination. The configuration information may indicate one or more preambles. The configuration information may indicate that the first RO of the first preamble is associated with the second RO of the second preamble. The configuration information may indicate that a first preamble index of the first preamble is associated with a second preamble index of the 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 for a Random Access Response (RAR) that includes a preamble index associated with a preamble combination or a preamble index associated with a first preamble and a second preamble. The WTRU may receive the RAR including the preamble index of the first preamble but not the preamble index of the second preamble and transmit the second preamble.

PRACH resource partitioning may be used to indicate one or more of the best SSB, 2-step to 4-step RACH, and/or message 3 size (group a to B). Another PRACH partition may be used based on one or more of the following features: redCap (e.g., indicating to the NW the type of device with reduced capabilities); SDT (e.g., distinguish RA procedures to support a larger payload size of SDT); covEnh (e.g., to indicate a repeated coverage enhancement requirement of Msg 3); slices (e.g., indicating high priority slices to NW and/or achieving slice isolation of RACH). For example, some features may be supported simultaneously by the same device (e.g., IIoT redcap devices that support SDT on a given slice). A partition may 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 may increase (e.g., exponentially) with the number of features. For example, to indicate a combination of k features, 2 ^k PRACH partitions may be used, assuming that these features are introduced together (e.g., without affecting legacy WTRU preamble selection). The number of partitions may be further increased if features are not introduced together (e.g., in successive versions) and/or legacy WTRU preamble selection is not changed. FIG. 2 illustrates an example of an exponential increase in the number of partitions used to indicate a plurality of features. For (e.g., each) feature combination, partitioning may be further repeated by SSB and/or by group a/B set. In an example, the overhead may 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 for (e.g., each) feature partition in this example, the total number of preambles (e.g., new preambles) that use the ad-hoc method to indicate a feature combination (e.g., new feature combination) may be: the number of preambles ^Ad-hoc (e.g., the number of required new preambles ^Ad-hoc) =2×n×p×2 ^K. For example, if n=6, k=4, p=8, the number of preambles is 1536 (24 ROs).

Physical Random Access Channel (PRACH) resources may include one or more of the following: PRACH resources on frequency, PRACH occasions or RACH Occasions (ROs) (e.g., in time), preamble formats (e.g., according to 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).

The small data may include uplink shared channel (UL-SCH) data (e.g., a non-Common Control Channel (CCCH)) transmitted by the WTRU, for example, in a non-connected mode.

In an example, msgA may include a preamble and a payload transmission on PRACH and Physical Uplink Shared Channel (PUSCH) resources, respectively, in a 2-step Random Access (RA) procedure (e.g., a 2-step RA procedure defined in TS 38.321).

In an example, msgB may include a downlink response to MsgA, which may be, for example, a successful Random Access Response (RAR), a fallback RAR, or a fallback indication defined in TS 38.321.

In an example, the RO may be a RACH occasion defined in TS 38.321, for example.

The preamble may include a specific combination (e.g., a unique combination) of two or more preamble transmissions.

The term features and term examples are used interchangeably in one or more examples herein. The use case may correspond to an indication of one or more WTRU features or capabilities.

The attribute of the scheduling information (e.g., uplink grant or downlink allocation) may include (e.g., consist of) at least one of: frequency allocation; aspects of time allocation, such as duration; a priority; modulation and coding scheme; transport Block Size (TBS); the number of spatial layers; the number of Transport Blocks (TBs) to be carried; a Transmission Configuration Indication (TCI) state or SRS Resource Indicator (SRI); repeating the times; whether the authorization is a configured authorization type 1, type 2, or dynamic authorization.

The indication of Downlink Control Information (DCI) may include (e.g., consist of) at least one of: an explicit indication of a Cyclic Redundancy Check (CRC) field or a radio network identifier (RNTI) for masking a Physical Downlink Control Channel (PDCCH) (e.g., PDCCH transmission); implicit indications of one or more of a characteristic such as DCI format, DCI size, control resource set (core set) or search space, aggregation level, and/or an identification of a first control channel resource for DCI (e.g., an index of a first Control Channel Element (CCE)), where a mapping between the characteristic and a value may be signaled by a Radio Resource Control (RRC) or a Medium Access Control (MAC).

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

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, slice. Depending on the capabilities of the WTRU, the WTRU may be configured to support different combinations of features herein. For example, the WTRU of the internet of things may be a RedCap device that supports SDT transmissions on a given slice. The partition 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 increase (e.g., exponentially) with the number of feature combinations. For example, to indicate a combination of k features, 2 ^k PRACH partitions may be used. For example, it may be assumed that these features are introduced together without affecting legacy WTRU preamble selection. For example, if features are not introduced together (e.g., in successive versions) and legacy WTRU preamble selection is not changed, the number of partitions may further increase. One or more examples herein may be used to increase capacity and/or efficiency without exponentially increasing partition with the number of feature combinations.

Multiple PRACH transmissions may be used for use case indication.

The WTRU may transmit a combination of two or more preamble transmissions to indicate one or more of a feature, a capability, a combination of features, a combination of capabilities, or a combination of features and capabilities. For example, the first preamble transmission or the first preamble may indicate one or more of the first feature, the first feature combination, and/or the first capability, and/or the second preamble transmission or the second preamble may be used for randomization (e.g., randomized preamble selection of multiple WTRUs) and/or an indication of one or more of the second feature, the second feature combination, and/or the second capability. The first preamble transmission or first preamble may correspond to an intersection of a plurality of features (e.g., a combination of features), and/or the second preamble transmission or second preamble may distinguish which of the features, for example, by indicating a distinction between the features. The (e.g., each) combination of the first preamble and the second preamble may be associated with a respective feature, a combination of features, or a set thereof. As shown in the example of fig. 3A, the WTRU may indicate feature combination 1 using a preamble set that includes preambles 54-57 on RO1 and preambles 0-15 on RO 2. In fig. 3A, a preamble set comprising 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 the first preamble and the second preamble may be associated with one feature.

The preamble may be used for use case indication.

The preamble transmission may include one or more preambles, e.g., 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 combination of features. 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 combination of features). For example, based on the feature combination, the second preamble transmission may be a transmission of a second preamble of the 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 a second preamble transmission or a second preamble (possibly for each feature, use case, or combination of features).

In an example, a set of preambles comprising a first subset and a second subset may be determined based on a combination of features. Fig. 3A illustrates an example of using a preamble set to indicate feature combinations. As shown in fig. 3A, the WTRU may transmit a preamble (e.g., 2 preambles) in the associated RO to indicate SSB and/or feature combinations. Based on the SSB and/or the combination of features that the WTRU wishes to indicate, the WTRU may determine the partition associated with the combination of features in RO1 and/or associated RO 2. The WTRU may select (e.g., randomly select) a preamble among preambles in the associated partition of RO1 and transmit msg1. The WTRU may select (e.g., randomly select) a preamble among 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) the preamble of RO1 from 56-59 and the preamble of RO2 from 17-32. In the example shown in fig. 3A, in RO1, there are 10 preambles per ssb×2 ssbs=20 preambles, and there are 64 (16×4 combinations) preambles out of 20 preambles+ro 2=84 preambles of all combinations of 2 SSBs. An alternative partition (e.g., a legacy partition) requiring similar randomness of (4+16) preambles per combination may require 20 preambles per ssb=20 preambles×2 ssbs×4 combinations=160 preambles per combination (which would require at least one RO per SSB). The example in fig. 3A may increase savings by more SSBs and more features and/or feature combinations.

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

The preamble may include a combination (e.g., a unique combination) of two or more preamble transmissions, e.g., a first preamble transmission and a second preamble transmission. As shown in fig. 3A, the first preamble transmission may be, for example, transmitting a preamble from a subset of preambles with preamble indices 54-57 on RO 1. The second preamble transmission may be, for example, transmitting a preamble from a subset of preambles with preamble indices 0-15 on RO 2. In an example, the NW may create a space of unique leading codes equal in size to: the number of preambles in the first subset x the number of preambles in the second subset. For example, on two ROs, each having 64 available preambles, the WTRU may select the preamble to indicate one of up to 64 ² unique indications. The number of possible unique indications in 2 transmissions of preamble = the number of possible preambles selected in the first RO x the number of possible preambles selected in the second RO.

The set of leading 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 an active lead code, 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 WTRU may receive an explicit list of N _sp combinations of preambles, where Nsp may be the size of the active set; the WTRU may determine the active set as a combination (e.g., all possible combinations) of a first subset of the first preambles and a second subset of the second preambles. By extension, the WTRU may determine the active set as a union of more than one such combined set of the plurality of subsets (e.g., a union of more than one such combined set of the first subset and the second subset). For example, the active set may be a union of a first combined set including combinations of the first preambles 32 to 47 and the second preambles 50 to 57 and a second combined set including combinations of the first preambles 48 to 63 and the second preambles 58 to 63. Each RO may be configured with a subset of preambles per feature combination. The network may configure a subset (i.e., whether it overlaps another feature). In some examples, overlapping (e.g., overlapping of preamble subsets) may be avoided.

The WTRU may be configured with more than one active set of preamble codes. The preamble active set may be configured based on one or more of use cases, SSBs, feature combinations or features, and/or a subset of PRACH resources.

The WTRU may transmit a first preamble of a preamble in a first set of ROs. The WTRU may transmit a second preamble of the 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 as, for example, the ROs of the first set being immediately in time (e.g., immediately after in time) to the ROs of the second set, or the ROs of the second set being immediately in time (e.g., immediately after in time) to the ROs of the first set. In some examples, the second RO of the second set and the first RO of the first set are discontinuous in the time domain.

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, PRACH resources to be used for transmission, a partition on RO, SSB to be used for transmission, RO to be used for transmission. The WTRU may receive signaling indicating parameters associated with the active sets (e.g., parameters defining each active set of a preamble or a preamble). 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 a preamble for a single preamble transmission (e.g., in legacy operation) and a preamble for a preamble transmission. For example, the WTRU may receive a parameter indicating a lowest possible value of a first preamble of a preamble (transmission) and a lowest possible value of a second preamble of the preamble (transmission). The WTRU may determine that the largest preamble index of a single preamble transmission (e.g., according to a legacy) in the RO corresponds to the lowest possible value associated with the leading preamble (transmission) in the RO.

The valid preamble may be identified by some index (e.g., a unique index). For example, the possible values for the index may range from 0 to Nv-1.Nv may be the total number of active lead codes across active sets (e.g., all active sets).

In some examples, the possible values may range from 64 to 64+nv-1 to reserve values 0 to 63 to 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.

The preambles may be concatenated. The preamble and/or RO mode may be configured.

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

For example, ROs may be associated based on configuration information. The NW may configure the WTRU with RO mode, for example, using configuration information indicating the associated RO. For example, the associated ROs (e.g., RO pairs) may be discontinuous 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. As shown in the example of fig. 3A, preamble 55 may be transmitted (e.g., by a WTRU) on partitions 54-57 of RO1 and then preamble 10 may be transmitted on partitions 0-15 of RO 2. RO1 and RO2 may not be continuous. The NW may identify the WTRU transmitting the first preamble on partition a of RO x and then transmitting the second preamble on partition B of RO y as RedCap WTRU performing small data, etc.

The first preamble may be selected and/or transmitted on the first RO. The NW may configure the RO subset suitable for the 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 features 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 the first feature (e.g., the feature indicated in the first preamble transmission) and the second feature (e.g., the feature indicated in the second preamble transmission). The NW may configure the WTRU with a partition of a preamble in a subsequent RO linked to one or more of the selected first preamble, the first RO, and/or the selected features indicated in the first preamble transmission. The WTRU may receive configuration information indicating an association of a partition of a preamble in the RO (e.g., a second RO following the first RO) with 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 be configured (e.g., preconfigured) with an association between the feature and the first and second preambles and/or ROs. The WTRU may be configured with an association between a feature (e.g., a combination of features) and a set of preambles (e.g., a first preamble and a second preamble). The WTRU may be configured with an association between the feature and the RO. In an example, the WTRU may be preconfigured (e.g., by the NW) with an association between the feature and the first and second preambles or ROs such that the WTRU does not send all feature combinations. Some combinations of functions may not be allowed. The WTRU may transmit from a subset of ROs for the second preamble transmission, depending on one or more of the selected first preamble, first RO, and/or feature. For example, the NW may not support a combination of slice WTRU capabilities and SDT capabilities. If the WTRU indicates to the NW that the WTRU is capable of supporting slicing, the WTRU may not send SDT capabilities 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.

The WTRU may be configured with a priority of WTRU-capable transmissions. In an example, where a combination of WTRU capabilities is transmitted, the WTRU may be configured (e.g., by the NW) with a priority of WTRU capability transmissions. For example, the WTRU may receive RedCap a priority indication from the NW that has a higher priority than other capabilities (e.g., coverage enhancement or SDT). If the WTRU supports at least RedCap capabilities, the WTRU may be configured to indicate RedCap capabilities (e.g., transmit RedCap WTRU) during the first preamble transmission. If the WTRU supports coverage enhancement functions in addition to RedCap or slicing functions, the WTRU may indicate this function during the second preamble transmission. The convenient configuration of the Tx/Rx parameters of the WTRU capabilities with higher priority may be achieved by priority and/or priority-based ordering (e.g., ordering of transmissions) of the WTRU capabilities.

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, a first preamble transmission may be indicated by the partitions 54-57 on RO1 in FIG. 3A, and a second preamble transmission may be indicated by the partitions 58-61 on RO1 in FIG. 3A.

Fig. 3 shows an example of ROs and/or partitions. Fig. 3 shows preamble partitioning across features and SSBs using the preamble transmitted on two ROs (e.g., RO1 and RO2, or RO3 and RO 4).

The RO selection may be based on (e.g., based on) the previously selected RO.

For example, depending on the feature or use case, the WTRU may be configured with an association of ROs (e.g., between ROs of the preamble) (e.g., through Radio Resource Control (RRC) or broadcast signaling). The WTRU may be configured or designated to indicate some characteristics (e.g., delay sensitive characteristics such as high priority slices) to the NW via a (e.g., single) preamble transmission. The WTRU may be configured or designated to indicate some features (e.g., other non-delay critical features or use cases (e.g., SDT, redcap, covEnh)) with two or more preamble transmissions.

The WTRU may be configured (e.g., via RRC or broadcast signaling) with the time between preamble transmission opportunities within the preamble (e.g., minimum time and/or maximum time), and/or with the number of ROs between preamble transmissions of the preamble (e.g., minimum and/or maximum number of ROs). For example, the WTRU may select (e.g., randomly select) the RO for the next preamble transmission within a 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 subset of the second preamble, 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 ROs and/or time differences from the first preamble transmission.

Fig. 4A shows an example of RO. Fig. 4A illustrates a preamble space (e.g., preamble hopping pattern) for a configuration of a second preamble for transmitting a preamble. The preamble space shown in fig. 4A may depend on the timing of the second RO (e.g., depending on whether the transmission of the second preamble is on RO2, RO4, or RO 6). Fig. 4B shows an example of RO. Fig. 4B shows a randomized hash function that may be used to determine the timing of the second RO of the leading amble. As shown in fig. 4B, WTRU 1 may transmit a second preamble on RO6 after 2 randomized ROs (e.g., RO3 and RO 5). In some examples, WTRU 2 may transmit a second preamble on RO6, a portion (e.g., region) of which may be affected by the inter-feature collision probability. For example, one or more parameters, variables, values, factors, or conditions may be configured for a feature, combination of features, and/or capability. As an example, for features, feature combinations, and/or capabilities, one or more of the following may be configured (e.g., by the NW), broadcast, or predefined: the number of preambles for each RO of the first transmission (e.g., first preamble transmission); a preamble start index for the first transmission; a set of ROs suitable for the first transmission, denoted here as "Romask _ ^st"; the number of preambles for each RO of the second transmission (e.g., second preamble transmission); a preamble start index for the second transmission; a set of ROs suitable for the second transmission, denoted here as "Romask _ ^nd"; the maximum duration (or maximum number of ROs) between the first preamble transmission and the second preamble transmission, denoted here as "maxPeriodbwPreambles"; the minimum duration (or minimum number of ROs) between the first preamble transmission and the second preamble transmission. The number of preambles for each RO for the first transmission, the Preamble start index for the first transmission, and Romask _ ^st may be used to indicate or define a Preamble space "preamble_subset_ ^st". The Preamble number of each RO for the second transmission, the Preamble start index Romask _ ^nd for the second transmission may indicate or define a Preamble space "preamble_subset_ ^nd". The WTRU may determine one or more of the parameters, variables, values, factors, or conditions herein based on, for example, features, feature combinations, and/or capabilities.

For example, the WTRU may be configured by configuring multiple preambles for each feature combination in a reserved region of a preamble of an RO (e.g., an RO shared with a legacy WTRU) via RRC information. For example, romask _ ^st may or may not be shared with a legacy WTRU, depending on the configuration. For example, romask _ ^nd may or may not be shared with legacy WTRUs depending on the configuration.

For example, after initiating an RA procedure to indicate a given feature combination, the WTRU may select a first Preamble from preamble_subset_1 ^st for transmission. After transmitting the first preamble, the WTRU may determine (e.g., randomly determine) the RO for the second preamble transmission. In an example, the WTRU may select an RO (e.g., randomly) for the second preamble transmission in ROs defined by Romask _ ^nd and within MaxPreiodbwPreambles from the instance of transmitting the first preamble (e.g., within maxPeriodbwPreambles from 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 expiration of the timer (e.g., using the next active preamble). In an example, the value of the timer may be randomly selected (e.g., initially between [0 and maxPeriodbwPreambles ]).

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

The WTRU may determine the Preamble index within preamble_subset_2 ^nd based on (e.g., according to) one or more of the following: 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 of time (and/or the number of ROs) between the first transmission and the second transmission. In an example, the WTRU may determine a preamble index for the second transmission using a formula.

The following is an example formula: the preamble index range for the second transmission "range = { preamble start index for the second transmission + offset value, preamble start index for the second transmission + offset value + preamble number for each RO of the second transmission }. The Offset value (Offset) used in the formula may be an Offset value that may 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 NW, for example. If the range exceeds preamble index 63, the range may be cyclically shifted and/or wrapped around between 0 and 63 to include the preamble {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 also apply to more than two preambles, more than two preamble transmissions, or more than two ROs.

RAR/MsgB monitoring may be performed.

Depending on the channel conditions or collisions, the NW may be able to successfully receive and/or decode the first preamble, e.g., not successfully receive or decode the second preamble, or the NW may be able to successfully receive and/or decode the second preamble, e.g., not successfully receive or decode the first preamble.

In the event 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 two conflicting WTRUs), for example, by signaling a leading preamble index in 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 PDCCH transmissions for reception of 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, the WTRU may skip PDCCH monitoring of the RAN/MsgB after the transmission of the first preamble if the transmission of the first preamble is followed by the transmission of the second preamble or the second preamble. If the WTRU has transmitted the preamble, the WTRU may monitor or attempt to decode a different RAR or MsgB format. For example, the different RAR or MsgB formats 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 and second preambles.

If the WTRU receives an 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., configured RAR or MsgB window) and/or consider the reception of Msg2/B to be successful. For example, the WTRU may initiate a monitoring window (e.g., a RAR or MsgB window) at a first symbol of an 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 that 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 herein).

The WTRU may monitor an RA-RNTI corresponding to the second RO, monitor an RA-RNTI corresponding to the first RO, monitor an RA-RNTI of an RA-RNTI corresponding to both the second RO and the first RO, or monitor an RA-RNTI corresponding to the second RO and an 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 RA-RNTI corresponding to the second RO, to monitor RA-RNTI corresponding to the first RO, to monitor RA-RNTI of RA-RNTI corresponding to both the second RO and the first RO, or to monitor RA-RNTI corresponding to the second RO and RA-RNTI corresponding to the first RO. The WTRU may monitor for an RA-RNTI corresponding to a preamble transmission associated with the preamble (e.g., a first preamble transmission or a second preamble transmission) and/or an RA-RNTI corresponding to the preamble, or for 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, a second RA-RNTI corresponding to the second preamble transmission). The WTRU may monitor a preamble RA-RNTI calculated in view of one or more of: the method may include allocating resources in a frequency domain for one of the ROs associated with the preamble (e.g., the first RO or the second RO), allocating resources in a time domain for a plurality of the ROs associated with the preamble (e.g., the first RO and the second RO), and allocating resources in a frequency domain for a plurality of the ROs associated with the preamble (e.g., the first RO and the second RO). In an example, the WTRU may monitor for an RA-RNTI that is equal to a sum of RA-RNTIs associated with respective ROs of some or all ROs associated with the lead code (e.g., a sum of RA-RNTIs associated with the first RO and RA-RNTIs associated with the second RO). In some examples, the RA-RNTI associated with the leading amble transmitted over 2 ROs may be calculated as ：RA-RNTI＝1+s_id_1^stRO+14×t_id_1^stRO+14×80×f_id_1^stRO+s_id_2^ndRO+14×t_id_2^ndRO+14×80×f_id_1^ndRO+14×80×8×ul_carrier_id equation 1 below

Equation 1 may apply to RA-RNTIs associated with leading ambles transmitted over more than 2 ROs.

The WTRU may monitor, for example, a Slot Format Indication (SFI) index in DCI schedule Msg 2/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 a plurality of 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 the RAR reception successful, e.g., if it corresponds to the SFI of the first RO, the second RO, or both. The WTRU may monitor for 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 ROs are associated with different ROs.

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

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

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 (RAPID) corresponding to a preamble (e.g., a first preamble or a second preamble) associated with a preamble or corresponding to the preamble, the WTRU may assume that the transmission of msg1 has been successful. The WTRU may again transmit the first preamble or a second preamble of the preamble set including the first preamble if, for example, the RAR or Msg2/B corresponding to the first preamble is not received within the RAR window. For example, the WTRU may retransmit the second preamble if the WTRU receives a RAR corresponding to the first preamble (e.g., corresponding only to the first preamble) or MsgB and/or the WTRU does not receive a RAR of the second preamble. The WTRU may transmit a third preamble from a subset of preambles including the second preamble if the WTRU receives a RAR corresponding to the first preamble (e.g., corresponding only to the first preamble) or MsgB and/or the WTRU does not receive a RAR of the second preamble.

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

RA-RNTI collision may be reduced.

The WTRU may use separate ROs with the same RA-RNTI (e.g., with the same slot index and frequency offset value). For example, two WTRUs (i.e., one legacy WTRU and another WTRU supporting PRACH partition/indication) may use two independent 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 having 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.

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

The WTRU may add an offset value to the RA RNTI equation to distinguish PDCCH monitoring associated with the WTRU from legacy WTRUs (e.g., to distinguish PDCCH monitoring of the WTRU from PDCCH monitoring of legacy WTRUs). The WTRU may utilize another value (e.g., another value that depends on the selected PRACH resource) to scramble the RA-RNTI.

The use case indication may not be based on RACH.

Subsequent indications may be used for feature combinations.

The WTRU may indicate support and/or request use of the feature set via a subsequent indication (e.g., after the preamble and/or initial transmission). The feature set may include (e.g., consist of) one feature or a combination of features. Whether the WTRU may indicate the feature set via a subsequent indication may be determined (e.g., limited) by the NW and/or configured, for example, via RRC signaling or via an explicit indication (e.g., in system information). The complete set of features may be indicated (e.g., uniquely indicated) 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 that the subsequent indication is to provide 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.

The subsequent indication may include information about and/or provide an indication of one or more of: support for features or WTRU capabilities; a request for use of a feature, or a request to terminate use of a feature; 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 features are mandatory and/or necessary for access to the NW (e.g., coverage enhancement); whether the subsequent indication includes a modification to the previous indication (e.g., adding or removing a feature of support).

For example, the supported feature set may be indicated via a list. The WTRU may include some or all of the features supported in the subsequent indication, such as all of the features supported in the subsequent indication or only those features that the WTRU is intended to use. The list may indicate (e.g., alternatively indicate) a list of features that the WTRU intends to enable or disable. For example, whether the WTRU desires to enable or disable a feature or feature list may be indicated (e.g., separate from the feature list) via a dedicated Information Element (IE) or bit. In some examples, the subsequent indication may represent an index value. The index value may point to a particular entry in a table (e.g., a table containing combinations of feature sets and/or a table containing possible combinations of feature sets). In some examples, feature set combinations and feature combinations may be used interchangeably. The table may be provided via one or more of, for example, in system information, via RRC signaling, or 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" and disabled and/or unsupported features may be classified as "0".

The WTRU may transmit a subsequent indication and/or communicate support for the feature set information and/or request to use the feature set information, e.g., via one or more of the following: additional bits in RACH preamble; PUSCH transmissions (e.g., using Msg3 and/or MsgA payloads); PUCCH transmission (e.g., via UCI); a MAC CE; RRC signaling, e.g., via capability reports or dedicated feature set IEs; a device type indication; NAS signaling; scheduling Request (SR).

The WTRU may select the resource, occasion, or method to provide 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 explicit request from NW via DCI, RAR, or system information); a connection state of the WTRU (e.g., the WTRU in an RRC connected state may transmit a subsequent indication, e.g., via MAC CE, PUSCH, SR, or RRC signaling; the WTRU in an RRC idle/inactive state may transmit a subsequent indication, e.g., via one or more of a dedicated preamble, msg3 UL grant, RRC message, or msgA PUSCH resources); whether the feature is necessary for RA (e.g., a WTRU that needs coverage enhancement may send at least the feature indication via, for example, a preamble transmission); a network decision whether support for this feature affects access control (e.g., the WTRU may select resources to communicate that the WTRU is RedCap WTRU before the RA procedure is complete, so that the WTRU can be rejected via an RRC reject message); a stage of the RA procedure (e.g., if the WTRU has received the RAR, the WTRU may include a subsequent indication on the Msg3 PUSCH resource, or if the WTRU has received Msg4, the subsequent indication may be included in the capability signaling); the previous subsequent feature indicates the number or number of transmission attempts; the number of features supported by the WTRU; whether the indication is an update to the previous indication.

Based on the transmission of the subsequent indication (e.g., upon transmission of the subsequent indication), the WTRU may assume that the feature is (de) activated and/or use the feature in the symbol immediately after 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 assuming that the feature is active when the explicit acknowledgement is received from the NW). The WTRU may determine an explicit acknowledgement (e.g., assuming an explicit acknowledgement), for example, via one or more of the following: HARQ ACK; RAR; msg4/MsgB; DCI is allocated to PDCCH transmission of the WTRU; PDSCH transmission; scheduling information; a bandwidth part (BWP) switch indication; RRC message.

A combination of features may be indicated. A WTRU may be provided with a set of valid feature sets from which to indicate the feature set combinations. The set of valid feature combinations may be indicated via a table or list with entries comprising (e.g. consisting of) valid or invalid feature combinations, or via mapping rules. One or more of the tables, lists, or mapping rules may signal to the WTRU via, for example, one or more of the following: system information, RACH configuration, RRC signaling, or DCI. The configuration may also include an applicable bandwidth (e.g., BWP) and/or whether the resources are on a Normal UL (NUL), a Supplemental UL (SUL), or both, for which the PRACH resources are valid for the feature or feature combination (e.g., for each feature or each feature combination). For example, one or more of system information, RACH configuration, RRC signaling, or DCI (or one or more of a table, list, or mapping rule) may include BWP on which PRACH resources are valid for a feature or combination of features and/or may indicate whether the resources are on NUL, SUL, or both.

Based on the transmission of the invalid set of feature combinations (e.g., upon transmission of the invalid set of feature combinations), one or more of the following may occur: the WTRU may be denied access to the NW (e.g., via an RRC reject message), retransmitted with a feature set of valid combinations, backed off to a 4-step RACH, retransmitted a preamble combination, and/or RA performed.

In some examples, the WTRU may group the features according to the stage at which the features are used (e.g., needed) in the connection establishment procedure. For example, the WTRU may group the features required to perform RA (e.g., coverage enhancement, redCap).

The WTRU may not have a valid PRACH resource to indicate the feature combination that initiates RA. If the WTRU does not have a valid PRACH resource to indicate the feature combination for which RA was initiated, the WTRU may perform one or more of the following: the WTRU may multiplex the feature or combination of features for which RACH is initiated in the payload of Msg3 or MsgA; the WTRU may select PRACH resources configured for a feature that is part of a desired feature combination, e.g., 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 combinations for which RA is triggered; for example, after RA completes successfully, 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 (e.g., after RA is successfully completed); the WTRU may switch its active UL and/or DL BWP to another BWP on which PRACH resources indicating the feature or combination of features are configured.

The WTRU may select PRACH resources configured to indicate the subset of features from the feature combinations for which RA is triggered. For example, when initiating RA for a feature combination, the WTRU may be configured or predefined with some priority rules to determine which PRACH resource to select, while the available PRACH resources in the active BWP (e.g., each available PRACH resource) are configured for a 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 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 the initiation of RA is indicated for SDT and Redcap, the WTRU may prefer PRACH resources configured for SDT. If the initiation of RA is indicated for CovEnh (e.g., msg3 or Msg1 repetition) and Redcap, the WTRU may prefer PRACH resources configured for CovEnh. If an initiate RA is indicated for SDT and CovEnh, the WTRU may prefer PRACH resources configured for SDT. Examples of priorities (e.g., priority rules) between features may be: priority of small data > priority of slice > priority of shrink capability > priority of overlay enhancement). Examples of priorities (e.g., priority rules) between features may be: priority of small data > priority of reduction capability > priority of slice > priority of coverage enhancement.

For example, after multiple retransmissions (or transmissions) or after an elapsed time (e.g., expiration of a timer since an initial preamble transmission), the WTRU may switch to different PRACH resources associated with different features within the feature combination that initiate the RA.

For example, if the WTRU selects PRACH resources configured to indicate a subset of features from the feature combinations for which RA is triggered, the WTRU may include a subsequent indication to indicate the missing features in the preamble indication. For example, the WTRU may select PRACH resources 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).

For example, depending on the active BWP, the WTRU may consider a subset of feature combinations valid. The WTRU may configure PRACH resources for a combination of features on the BWP subset and may, for example, consider the combination of features to be valid for BWP (e.g., valid for the BWP subset only).

The WTRU may switch BWP. For example, the WTRU may switch its active BWP (e.g., UL BWP and/or DL BWP) to an initial BWP or BWP (e.g., indicated by BWP index), wherein the feature combination is considered valid (or configured) upon RA initiation, e.g., based on one or more of the following: if the active BWP (e.g., active UL BWP) does not include valid PRACH resources to perform RACH indication (e.g., RACH indication to initiate a feature of RACH); if the initial BWP is configured with PRACH resources for which the characteristic combination (or subset) of RA is triggered.

The WTRU may indicate features or feature combinations in RA procedures initiated in a subset of modes (e.g., idle, inactive, and/or connected state). In the connected state, the WTRU may use PRACH resources associated with a feature or combination of features for a particular 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 combination of features of RA procedures triggered in 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 combination of features. In the connected state, the WTRU may use PRACH resources associated with a feature or combination of features (e.g., if valid or available in active BWP) for RA-SR procedures initiated by data arrival 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 combination of features to the triggered SR. The WTRU may select a valid PRACH resource or any valid PRACH resource for transmission associated with the RA-SR procedure (e.g., if there is no valid PRACH resource for a feature or combination of features in the active BWP in the connected state).

For example, in an inactive state, if an RA is initiated to indicate a feature combination that includes SDT, the WTRU may multiplex in the small data payload an indication of other features not shown configured for PRACH indication in RA-SDT resources (e.g., one or more of coverage enhancement indication, high priority slice, slice index, or reduced capability indication in the payload).

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

In some configurations, for example, a WTRU may have PRACH partitioning for some features or combinations of features on only the group a preamble, only the group B preamble, or both. The WTRU may select a preamble group (e.g., group a or group B), for example, depending on whether the feature or combination of features to be indicated is configured. For example, if PRACH resources indicating a feature or combination of features are not configured for the group B preamble, the WTRU may use group a to indicate the combination of features 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 PRACH resources indicating features or feature combinations are not configured for the group a preamble, the WTRU may use group B to indicate feature combinations 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 multiple retransmissions or transmissions (or time consuming), the WTRU may change the preamble set of preamble retransmissions.

The following may be an example of allocation of extended RA occasions in the time domain in a multi SSB cell. Fig. 5 shows an example of allocation of extended RA occasions in the time domain in a multi SSB cell. An example of an association (e.g., a predefined association) between the timing of the second RO and the timing of the first RO of the preamble, which is configured for each SSB set, is shown in fig. 5. For example, to transmit the second preamble during an associated period associated with the SSB burst, the WTRU may be configured with an extended RO. For an associated legacy RO configured with a subset of SSBs, the WTRU may be configured with an associated second extended RO before mapping a next associated period of time for the same subset of SSBs. This is illustrated in one or more of the figures herein (e.g., fig. 5). The WTRU may configure an RO mask associated with which ROs are extension ROs for the second transmission and which SSB subset is associated with the extension ROs (e.g., each extension RO) through RRC or broadcast signaling. It may be assumed (e.g., by the WTRU) that the extended RO follows an integer number of associated time periods and/or SSB mapping periods. The extended RO may be configured to frequency multiplex the SSB subsets 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 time slot, or in a time slot in which SSB is applicable/broadcast, possibly with a configured or predefined time gap between the two ROs to allow separation in the transmit power domain. For example, in a similar manner to the association configured between PRACH and PUSCH occasions in a type 2RA procedure, a WTRU may be configured with an association between multiple ROs (e.g., two ROs).

The following may be an example of analysis of PRACH overhead between PRACH partitions using single preamble transmissions 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., having two ROs, each RO having 64 available preambles).

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

PRACH capacity gain may be achieved. For example, at the simplest minimum, PRACH capacity gain may be due to the feature combining partition in the second RO not needing to be repeated for each SSB and each msg3 group set, as spatial separation between WTRUs is exploited.

If multiple (e.g., two) WTRUs simultaneously select the same SSB and the same combination of features in a first RO (e.g., preamble collision in the first RO), the WTRUs may be distinguished or separated by a second preamble transmission if the WTRUs randomly select different preamble indices in a 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 a second preamble transmission by a feature partition in a second RO in the preamble index field. If multiple (e.g., two) WTRUs select different SSBs in a first RO but the same combination of features, the WTRUs (e.g., two WTRUs) may further randomize their preamble selections in a 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 a normal 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 the msg1 transmission to be successful.

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

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., the gNB receiver) may combine two transmissions to increase the coverage of msg1, e.g., as long as they are from the same root sequence and the gNB does not detect preamble collision (e.g., even if the selected preambles have different indexes). For example, when the WTRU is in poor coverage, the NW may not correctly detect the first preamble by itself, but may combine the reception of the first preamble with the second preamble for better estimation and/or detection.

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

While the implementations described herein may consider 3GPP specific protocols, it should be appreciated that the implementations described herein are not limited to this scenario and may be applicable to other wireless systems. For example, while the solutions described herein consider LTE, LTE-a, new air interface (NR), or 5G specific protocols, it should be understood that the solutions described herein are not limited to this scenario, and are applicable to other wireless systems as well.

The processes described above may be implemented in computer programs, software and/or firmware incorporated in a computer readable medium for execution by a computer and/or processor. Examples of computer readable media include, but are not limited to, electronic signals (transmitted over 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, internal hard disks and removable disks), magneto-optical media, and optical media (such as Compact Disks (CD) -ROM disks, and/or Digital Versatile Disks (DVD)). A processor associated with the software may be used to implement a radio frequency transceiver for the WTRU, the terminal, the base station, the RNC, and/or any host computer.

Claims

1. A wireless transmit/receive unit (WTRU), the WTRU comprising:

a processor configured to:

Receiving configuration information, wherein the configuration information indicates a plurality of associated random access channel opportunities (ROs), wherein the plurality of associated ROs comprises a first RO and a second RO;

determining a feature combination associated with the WTRU;

Determining a preamble set based on the feature combination associated with the WTRU, wherein the preamble set includes a first preamble subset associated with the first one of the plurality of associated ROs and includes a second preamble subset associated with the second one of the plurality of associated ROs; and

A first preamble of the first preamble subset is transmitted on the first RO of the plurality of associated ROs and a second preamble of the second preamble subset is transmitted on the second RO of the plurality of associated ROs.

2. The WTRU of claim 1 wherein the first preamble transmitted on the first RO indicates the feature combination and the second preamble transmitted on the second RO indicates additional information associated with the feature combination.

3. The WTRU of claim 2, wherein the additional information associated with the feature combination indicates one or more of: the features of the feature combination, the differences between features of the feature combination, or randomized preamble selection for a plurality of WTRUs, wherein each of the plurality of WTRUs selects the feature combination.

4. The WTRU of claim 1, wherein the combination of features comprises one or more features, wherein one feature of the one or more features is indicated by the first preamble transmitted on the first RO and the second preamble transmitted on the second RO, and wherein each of the first preamble and the second preamble indicates the feature, or a combination of the first preamble and the second preamble indicates the feature.

5. The WTRU of claim 1, wherein the configuration information indicates an association of the preamble set with the feature combination, an association of the first preamble subset with the first RO, and an association of the second preamble subset with the second RO, and wherein the preamble set is determined further based on the configuration information indicating the association of the preamble set with the feature combination.

6. The WTRU of claim 1, wherein the processor is configured to determine at least one of the first RO and the second RO based on the configuration information, wherein the second RO is immediately in time to the first RO in a time domain or the second RO and the first RO are discontinuous in the time domain.

7. The WTRU of claim 1, wherein the processor is configured to attempt to decode a Random Access Response (RAR) using a random access radio network temporary identifier (RA-RNTI) associated with a preamble of the preamble set or using a RA-RNTI associated with one or more of the first RO or the second RO.

8. The WTRU of claim 1, wherein the processor is configured to:

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 was not received; and

Transmitting a third preamble of the second subset of preambles on a third RO based on the determination that the RAR for the second preamble transmitted on the second RO was not received, wherein the third preamble is the same as or different from the second preamble.

9. The WTRU of claim 1, wherein the processor is configured to:

determining that a RAR for the second preamble transmitted on the second RO was not received;

determining a feature of the feature combination, wherein the second preamble transmitted on the second RO indicates the feature; and

The feature is indicated in a payload of a RAR grant based on the determination that the RAR for the second preamble transmitted on the second RO was not received.

10. A method performed by a wireless transmit/receive unit (WTRU), the method comprising:

determining a feature combination associated with the WTRU;

11. The method of claim 10, wherein the first preamble transmitted on the first RO indicates the feature combination and the second preamble transmitted on the second RO indicates additional information associated with the feature combination.

12. The method of claim 11, wherein the additional information associated with the feature combination indicates one or more of: the features of the feature combination, the differences between features of the feature combination, or randomized preamble selection for a plurality of WTRUs, wherein each of the plurality of WTRUs selects the feature combination.

13. The method of claim 10, wherein the configuration information indicates an association of the preamble set with the feature combination, an association of the first preamble subset with the first RO, and an association of the second preamble subset with the second RO, and wherein the preamble set is determined further based on the configuration information indicating the association of the preamble set with the feature combination.

14. The method of claim 10, the method further comprising:

15. The method of claim 10, the method further comprising: