RU2812761C2 - Method for selection of random access channel (rach) preamble depending on distance in non-terrestrial networks (ntn) and wireless transmitting/receiving unit (wtru) - Google Patents

Abstract

FIELD: wireless communication.

SUBSTANCE: receiving, through a wireless transmitting/receiving unit (WTRU) from a network access point (NAP), a plurality of preambles and corresponding thresholds related to propagation delay, and determining information related to propagation delay associated with the distance between the WTRUs and a NAP or a location within the NAP coverage area, then selecting a subset of preambles from the plurality of preambles based on certain information related to propagation delay, randomly selecting a preamble from the selected subset of preambles, and sending the randomly selected NAP preamble.

EFFECT: enabling selection of a subset of preambles from a plurality of preambles based on information related to the propagation delay.

20 cl, 12 dwg

Description

Cross reference to related applications

This application claims benefit from U.S. Provisional Patent Application No.: 62/752,453, filed October 30, 2018, the contents of which are incorporated herein by reference.

Field of invention

The embodiments described herein generally relate to wireless communications and, for example, to methods, apparatus and systems for selecting a RACH preamble based on distance in an NTN.

Brief description of graphic materials

A more detailed explanation is contained in the detailed description provided below as an example in combination with the accompanying graphics. The figures in the description are examples. Accordingly, the figures and detailed description are not to be construed as limiting, but other equally effective examples are possible and likely. In addition, like reference numbers in the figures indicate like elements, and wherein:

in fig. 1A is a system diagram illustrating an example of a communication system in which one or more of the described embodiments may be implemented;

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

in fig. 1C is a system diagram illustrating an example of a radio access network (RAN) and an example of a core network (CN) that may be used in the communication system illustrated in FIG. 1A, in accordance with an embodiment;

in fig. 1D is a system diagram illustrating an additional example of a RAN and an additional example of a CN that may be used in the communication system illustrated in FIG. 1A, in accordance with an embodiment;

in fig. 2 is a diagram illustrating a typical connection establishment procedure for radio resource control (RRC);

in fig. 3 is a diagram illustrating the propagation delay divergence within a narrow beam;

in fig. 4 is a diagram illustrating a typical synchronization advance procedure;

in fig. 5 is a diagram illustrating position estimation relative to differences in nadir and/or propagation delay in the NTN;

in fig. 6 is a general flowchart illustrating a typical procedure for selecting RACH preambles depending on distance in an NTN;

in fig. 7 is a flowchart illustrating a typical procedure for performing a RACH procedure;

in fig. 8 is a flowchart illustrating another exemplary procedure for selecting RACH preambles based on parameters/information related to propagation delay; And

in fig. 9 is a flow diagram illustrating another exemplary procedure using a Random Access Radio Network Temporary Identifier (RA-RNTI), which is a function of, includes, or is derived from a parameter/information related to propagation delay.

Detailed description

Example networks for implementing embodiments

As noted previously, embodiments may be implemented in a WTRU, a robotic vehicle, an automobile, an IoT equipment, any device that moves, or other communications device, which in turn may be used in a communications network. The following section describes some examples of WTRUs and/or other communications devices and the networks in which they may be embedded.

In fig. 1A is a diagram illustrating an example of a communications system 100 in which one or more of the described embodiments may be implemented. The communication system 100 may be a multiple access system from which a plurality of wireless communication users receive content such as voice, data, video, messaging, broadcast, etc. The communications system 100 may be configured to provide multiple wireless users with access to such content by sharing system resources, including wireless bandwidth. For example, communication systems 100 may use one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), Orthogonal Frequency Division Access (OFDMA), Single Carrier FDMA (SC-FDMA), Extended OFDM with Unredundant Extended Discrete Fourier Transform (DFT) with Burst Sync (ZT UW DTS-s OFDM), OFDM with Burst Sync (UW-OFDM) , OFDM with resource block filtering, filter block multi-carrier (FBMC), etc.

As shown in FIG. 1A, communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104/113, CN 106/115, public switched telephone network (PSTN) 108, Internet network 110, and others. network 112, although it should be understood that the described embodiments contemplate the possibility of employing 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 interact in a wireless communications environment. For example, WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a station and/or STA, may be configured to transmit and/or receive radio signals and may include a user equipment (UE), a mobile station, a fixed or mobile subscriber unit , subscriber module, pager, cell phone, personal digital assistant (PDA), smartphone, laptop, netbook, personal computer, wireless sensor, Mi-Fi hotspot or device, Internet of Physical Things (IoT) device, watch or other wearable device, head-mounted display (HMD), vehicle, radio-controlled unmanned aerial vehicle, medical device and applications (for example, those used in remote surgery), industrial device and applications (for example, robot and/or other wireless devices operating in industrial and/or or automated process chain), a device related to consumer electronics, a device operating in a commercial and/or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

Communication systems 100 may also include a base station 114a and/or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interact with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communications networks, such as CN 106/115, Internet network 110 and/or other networks 112. By way of example, base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an eNode-B (eNB), a Home Node-B (HNB), a Home eNode -B (HeNB), gNB, NR Node-B, point controller, access point (AP), wireless router, etc. Although each of the base stations 114a, 114b is shown as a separate element, it should be understood 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, which may also include other base stations and/or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. P. Base station 114a and/or base station 114b may be configured to transmit and/or receive radio signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage for wireless service in a specific geographic area, which may be relatively fixed or which may change over time. The cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e. one for each cell sector. In an embodiment, base station 114a may employ multiple input multiple output (MIMO) technology and employ multiple transceivers for each cell sector. For example, beamforming can be used to transmit and/or receive signals in desired spatial directions.

Base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d via radio interface 116, which may be any suitable wireless communication system (e.g., for transmitting signals in the radio frequency (RF), microwave, spectrum centimeter waves, micrometer wave spectrum, infrared (IR), ultraviolet (UV) spectrum, visible light spectrum, etc.). Air interface 116 may be established using any suitable radio access technology (RAT).

More specifically, as stated above, the communication system 100 may be a multiple access system, and one or more channel access schemes may be used, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, base station 114a in RAN 104/113 and WTRUs 102a, 102b, 102c may implement a radio technology such as universal terrestrial access (UTRA) for universal mobile communications system (UMTS), in which radio interface 115/116 may be installed /117 using Wideband CDMA (WCDMA). WCDMA may include communication protocols such as High Speed Packet Access (HSPA) and/or enhanced HSPA (HSPA+). The HSPA protocol may include High Speed Downlink (DL) Packet Access (HSDPA) and/or High Speed Uplink (UL) Packet Access (HSUPA).

In an embodiment, base station 114a and WTRU 102a, 102b, 102c may implement a radio technology such as an enhanced UMTS Terrestrial Radio Access (E-UTRA) network that may establish air interface 116 using the Long Term Evolution (LTE) standard, and /or LTE-Advanced (LTE-A), and/or LTE-Advanced Pro (LTE-A Pro).

In one embodiment, base station 114a and WTRU 102a, 102b, 102c may implement a radio technology such as NR Radio Access, which may establish radio interface 116 using New Radio (NR) technology.

In an embodiment, a variety of radio access technologies may be implemented in base station 114a and WTRU 102a, 102b, 102c. For example, the base station 114a and the WTRU 102a, 102b, 102c may collectively implement LTE radio access and NR radio access, for example, using dual connectivity (DC) principles. Thus, the radio interface employed by the WTRU 102a, 102b, 102c may be characterized by the use of multiple types of radio access technologies and/or transmissions directed to/from base stations of multiple types (eg, terminals and gNBs).

In other embodiments, base station 114a and WTRU 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., WiFi), IEEE 802.16 (i.e., global compatibility for microwave access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Evolution of the GSM standard with increased data transfer rate (EDGE), GSM EDGE (GERAN), etc.

Base station 114b shown in FIG. 1A may be, for example, a wireless router, a Home Node B, a Home eNode B, or an access point, and may use any suitable RAT to facilitate wireless communications in a localized area, such as a commercial establishment, a residential premises, vehicle, educational institution, industrial facility, air corridor (for example, for use by unmanned radio-controlled aerial vehicles), roadway, etc. In one embodiment, base station 114b and WTRU 102c, 102d may implement radio technology such as IEEE 802.11 to create a wireless local area network (WLAN). In an embodiment, base station 114b and WTRU 102c, 102d may implement radio technology such as IEEE 802.15 to create a wireless personal area network (WPAN). In another embodiment, base station 114b and WTRU 102c, 102d may use cell-based RATs (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to create a picocell or femtocells. As shown in FIG. 1A, base station 114b may have a direct connection to Internet 110. Thus, base station 114b may not need to access Internet 110 via CN 106/115.

The RAN 104/113 may communicate with the CN 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 WTRU 102a , 102b, 102c, 102d. Data may have different quality of service (QoS) requirements, such as different performance requirements, latency requirements, fault tolerance requirements, reliability requirements, data rate requirements, mobility requirements, etc. The CN 106/115 network can provide call control, billing services, location-based mobile services, prepaid calls, Internet connectivity, video distribution, etc. and/or perform high-level security functions such as user authentication. Although in FIG. 1A does not show this, it should be understood that RAN 104/113 and/or CN 106/115 may directly or indirectly communicate with other RANs that use the same RAT as RAN 104/113 or a different RAT. For example, in addition to connecting to RAN 104/113, which may use NR radio technology, CN 106/115 may also communicate with another RAN (not shown) using GSM, UMTS, CDMA 2000, WiMAX, E radio technology. -UTRA or WiFi.

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

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

In fig. 1B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1B, WTRU 102 may include, but are not limited to, processor 118, transceiver 120, transmit/receive element 122, speaker/microphone 124, keyboard 126, display/touchpad 128, non-removable storage 130, removable storage 132, source 134 power supply, global positioning system (GPS) chipset 136, and/or other peripheral devices 138. It should be understood that the WTRU 102 may include any subcombination of the above elements and still be consistent with the embodiment.

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 coupled to a DSP core, a controller, a microcontroller, application specific integrated circuits (ASICs), field programmable circuits gate arrays (FPGA), integrated circuit (IC) of any other type, state machine, etc. The processor 118 may perform signal encoding, data processing, power control, input/output processing, and/or any other functionality by which the WTRU 102 operates in a wireless communications environment. The processor 118 may be coupled to a transceiver 120, which may be coupled to a transmit/receive element 122. Although FIG. 1B, processor 118 and transceiver 120 are shown as separate components, it should be understood that processor 118 and transceiver 120 may be integrally integrated into an electronic unit or chip.

Transmit/receive element 122 may be configured to transmit signals to or receive signals from a base station (eg, base station 114a) over air interface 116. For example, in one embodiment, transmit/receive element 122 may be an antenna configured to transmit and/or receive RF signals. In an embodiment, the transmit/receive element 122 may be an emitter/detector configured to transmit and/or receive, for example, signals in the IR, UV, or visible light spectrum. In yet another embodiment, transmit/receive element 122 may be configured to transmit and/or receive signals in both the RF and visible light spectrum. It should be understood that the transmitter/receiver element 122 may be configured to transmit and/or receive any combination of wireless signals.

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

Transceiver 120 may be configured to modulate signals to be transmitted by transmitter/receiver element 122, as well as demodulate signals received by transmitter/receiver element 122. As noted above, WTRU 102 may have multi-mode capabilities. Thus, transceiver 120 may include a plurality of transceivers that enable WTRU 102 to communicate over multiple RATs, such as NR and IEEE 802.11, for example.

The processor 118 of the WTRU 102 may be coupled to a speaker/microphone 124, a keyboard 126, and/or a display/touch panel 128 (e.g., a liquid crystal display (LCD) or an organic light-emitting diode (OLED) display) and may receive user input from them. Processor 118 may also output user data to speaker/microphone 124, keyboard 126, and/or display/touchpad 128. Additionally, processor 118 may access information from any type of suitable storage device, such as non-removable storage device 130 and/or removable storage device 132, and store data thereon. Non-removable storage device 130 may include random access memory (RAM), read only memory (ROM), hard disk drive, or any other type of storage device. Removable storage device 132 may include a subscriber identity module (SIM) card, a memory card, a secure digital storage (SD) card, or the like. In other embodiments, processor 118 may access and store information from a storage device that is not physically located in the WTRU 102, such as on a server or home computer (not shown).

Processor 118 may receive power from power supply 134 and may be configured to manage power and/or distribute power to other components in WTRU 102. Power supply 134 may be any suitable device for supplying power to WTRU 102. For example, power supply 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells , fuel cells, etc.

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) relative to 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. location over air interface 116 from a base station (eg, base stations 114a, 114b) and/or determine location based on the timing of signals received from two or more adjacent base stations. It should be understood that the WTRU 102 may obtain location information through any suitable location method and still be consistent with the embodiment.

Processor 118 may be further coupled to other peripheral devices 138, which may include one or more software and/or hardware modules that provide additional features, functionality, and/or wired or wireless communication capabilities. For example, peripheral devices 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photography and video), a universal serial bus (USB) port, a vibration device, a television transceiver, a wireless headset, a Bluetooth® module, a radio module with frequency modulation (FM), digital music player, multimedia player, video game device module, Internet browser, virtual reality and/or augmented reality (VR/AR) device, activity tracker, etc. Peripherals 138 may include one or more sensors, where the sensors may be one or more of a gyroscope, an accelerometer, a Hall sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; geographic position sensor; altimeter, light sensor, touch sensor, magnetometer, barometer, gesture sensor, biometric sensor and/or humidity sensor.

The processor 118 of the WTRU 102 may operably interface with various peripheral devices 138, including, for example, any of one or more accelerometers, one or more gyroscopes, a USB port, other interfaces/communications ports, a display, and/or other visual/audio indicators, to implementing exemplary embodiments described herein.

WTRU 102 may include a full-duplex radio device for which the transmission and reception of some or all of the signals, such as those associated with specific subframes for both UL (e.g., transmit) and downlink (e.g., receive), may be carried out jointly and/or simultaneously. A full-duplex radio device may include an interference control unit to reduce and/or substantially eliminate self-interference using either hardware (e.g., an inductor) or signal processing via a processor (e.g., a separate processor (not shown) or processor 118) . In an embodiment, WTRU 102 may include a half-duplex radio for transmitting and receiving some or all signals (eg, associated with specific subframes) for both UL (eg, transmit) and downlink (eg, receive).

In fig. 1C is a system diagram illustrating RAN 104 and CN 106 in accordance with an embodiment. As noted above, RAN 104 may use E-UTRA radio technology to communicate with WTRUs 102a, 102b, 102c over radio interface 116. RAN 104 may also communicate with CN 106.

The RAN 104 may include eNode-Bs 160a, 160b, 160c, although it should be understood that the RAN 104 may include any number of eNode-Bs and still be consistent with the embodiment. Each eNode-B 160a, 160b, 160c may include one or more transceivers for communicating with the WTRU 102a, 102b, 102c over air interface 116. In one embodiment, the eNode B 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a may, for example, employ multiple antennas to transmit wireless signals to and/or receive wireless signals from the WTRU 102a.

Each eNode-B 160a, 160b, 160c may be associated with a specific cell (not shown) and may be configured to make radio resource management decisions, handover decisions, UL and/or DL user scheduling, and the like. As shown in FIG. 1C, eNode-B 160a, 160b, 160c can communicate with each other via the X2 interface.

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. Although each of the above elements is shown as part of CN 106, it should be understood that any of these elements may be owned by and/or provided for use by an entity other than the CN operator.

The MME 162 may be connected to each eNode B 160a, 160b, 160c in the RAN 104 via an S1 interface and may serve as a management node. For example, MME 162 may be responsible for authenticating users of WTRUs 102a, 102b, 102c, channel activation/deactivation, selecting a specific serving gateway during initial connection of WTRUs 102a, 102b, 102c, and the like. MME 162 may provide a control plane function for switching between RAN 104 and other RANs (not shown) that use other radio technologies, such as GSM and/or WCDMA.

The SGW 164 may be connected to each eNode B 160a, 160b, 160c in the RAN 104 via the S1 interface. SGW 164 may essentially route and forward user data packets to and from WTRUs 102a, 102b, 102c. SGW 164 may perform other functions, such as user plane binding during handover between eNode B base stations, initiating paging when DL data is available to WTRU 102a, 102b, 102c, managing and storing context of WTRU 102a, 102b, 102c, etc. P.

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

CN 106 can facilitate data exchange with other networks. For example, CN 106 may provide WTRU 102a, 102b, 102c access to circuit switched networks, such as PSTN 108, to facilitate communications between WTRU 102a, 102b, 102c and traditional landline communications devices. For example, CN 106 may include an IP gateway (eg, an IP multimedia subsystem (IMS) server) that acts as an interface between or communicates with CN 106 and PSTN 108. In addition, CN 106 may provide WTRU 102a, 102b, 102c access to other networks 112, which may include other wired and/or wireless networks that are owned and/or provided for use by other service providers.

Although the WTRU is described in FIG. 1A-1D as a wireless terminal, it is contemplated that in certain exemplary embodiments a wired communications interface to a communications network may be used with such a terminal (eg, temporarily or permanently).

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

A WLAN in Basic Service Set (BSS) infrastructure 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 to or interface with a distribution system (DS), or communicate over another type of wired/wireless network that carries traffic into the BSS and/or outside the BSS. Traffic to an STA originating outside the BSS may arrive through the AP and may be delivered to the STA. Traffic originating from the STA to recipients outside the BSS may be forwarded to the AP for delivery to the appropriate recipients. Traffic between STAs within a BSS may be sent through an AP, for example, if a source STA can send traffic to the AP and the AP can deliver traffic to a destination STA. Traffic between STAs within a BSS may be considered and/or referred to as peer-to-peer traffic. Peer-to-peer traffic may be transmitted between (eg, directly between) a source STA and a destination STA when establishing a forward link (DLS). In certain exemplary embodiments, the DLS may use 802.11e DLS or 802.11z Tunneled DLS (TDLS). A WLAN using Independent BSS (IBSS) mode may not have an AP, and STAs (eg, all of the STAs) within or using IBSS may communicate directly with each other. In this document, IBSS mode may sometimes be referred to as direct connection mode.

When using the 802.11ac infrastructure operating mode or similar operating mode, the AP can transmit a beacon over a fixed channel, such as a primary channel. The primary channel may have a fixed width (eg 20 MHz bandwidth) or a width dynamically set by signaling. The primary channel may be a BSS operating channel and may be used by the STA to establish a connection with the AP. In certain exemplary embodiments, carrier sense multiple access and collision avoidance (CSMA/CA) may be implemented, such as in 802.11 systems. The STAs (eg, each STA), including the AP, can detect the primary channel for the CSMA/CA. When the primary channel is detected/detected and/or determined to be occupied by a particular STA, that particular STA may be switched off. One STA (eg, only one station) can transmit at any given time in a given BSS.

To implement high throughput (HT) STA communication, a 40 MHz channel can be used, for example, by combining a primary 20 MHz channel with an adjacent or non-adjacent 20 MHz channel to form a 40 MHz channel.

Ultra High Throughput (VHT) STAs can support 20 MHz, 40 MHz, 80 MHz, and/or 160 MHz channel widths. 40 MHz and/or 80 MHz channels can be formed by combining continuous 20 MHz channels. A 160 MHz channel can be formed by combining 8 continuous 20 MHz channels or by combining two non-continuous 80 MHz channels, which can be called an 80 + 80 configuration. For an 80 + 80 configuration, the data after encoding the channel can pass through a segment analyzer, which can divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time domain processing can be performed separately on a per-stream basis. Streams can be mapped to two 80 MHz channels and data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the above operation for the 80+80 configuration can be inverted, and the combined data can be sent to the media access control (MAC) device.

02.11af and 802.11ah support 1 GHz submodes. Channel bandwidths and carriers are reduced in 802.11af and 802.11ah relative to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz and 20 MHz bandwidths in unused television spectrum (TVWS), and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz and 16 MHz bandwidths using spectrum. different from TVWS. In an exemplary embodiment, 802.11ah may support metered control/machine-to-machine communications such as MTC devices within a macro coverage area. MTC devices may have certain capabilities, such as limited capabilities, including supporting (eg, only supporting) certain and/or limited bandwidths. MTC devices may include a battery having a battery life that exceeds a threshold value (eg, to provide very long battery life).

WLAN systems that can support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel that can be designated as the primary channel. The primary channel may have a bandwidth equal to the largest total operating bandwidth supported by all STAs in the BSS. The primary channel bandwidth may be set and/or limited by an STA from among all STAs operating in the BSS that supports the lowest bandwidth operating mode. In the 802.11ah example, the primary channel could be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) 1 MHz mode, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz , 16 MHz and/or operating modes with other channel bandwidths. Carrier detection and/or network allocation vector (NAV) parameters may depend on the state of the primary channel. If the primary channel is busy, for example due to an STA (which only supports 1 MHz operation) transmitting to the AP, all available frequency bands may be considered occupied, even if most frequency bands are still unoccupied and may be available.

In the United States of America, the available frequency bands that can be used by 802.11ah range from 902 MHz to 928 MHz. Available frequency bands in Korea are from 917.5 MHz to 923.5 MHz. Available frequency bands in Japan are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah ranges from 6 MHz to 26 MHz depending on the country code.

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

RAN 113 may include gNBs 180a, 180b, 180c, although it should be understood that RAN 113 may include any number of gNBs and still be consistent with an embodiment. Each gNB 180a, 180b, 180c may include one or more transceivers for communicating with the WTRU 102a, 102b, 102c over air interface 116. In one embodiment, the gNB 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 108b may use beamforming to transmit signals to and/or receive signals from gNBs 180a, 180b, 180c. Thus, gNB 180a, for example, may use multiple antennas to transmit radio signals to and/or receive radio signals from WTRU 102a. In an embodiment, gNB 180a, 180b, 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple carrier components (not shown) to WTRU 102a. A subset of these carrier components may be in unlicensed spectrum, while the remaining carrier components may be in licensed spectrum. In an embodiment, gNBs 180a, 180b, 180c may implement Co-Multipoint Negotiation (CoMP) technology. For example, WTRU 102a may receive consistent transmissions from gNB 180a and gNB 180b (and/or gNB 180c).

The WTRUs 102a, 102b, 102c may communicate with the gNB 180a, 180b, 180c using transfers associated with a scalable numerical value. For example, OFDM symbol spacing and/or OFDM subcarrier spacing may differ for different transmissions, different cells, and/or different portions of the wireless transmission spectrum. WTRUs 102a, 102b, 102c may communicate with gNB 180a, 180b, 180c using subframes or transmit time intervals (TTIs) of varying or scalable durations (e.g., containing varying numbers of OFDM symbols and/or having constant varying absolute time durations) .

The gNBs 180a, 180b, 180c may be configured to communicate with the WTRU 102a, 102b, 102c in a standalone configuration and/or a non-standalone configuration. In a standalone configuration, the WTRU 102a, 102b, 102c can communicate with the gNB 180a, 180b, 180c without simultaneously accessing other RANs (eg, such as eNode-B 160a, 160b, 160c). In a standalone configuration, the WTRU 102a, 102b, 102c may use one or more gNBs 180a, 180b, 180c as a mobility reference point. In a standalone configuration, WTRU 102a, 102b, 102c can communicate with gNB 180a, 180b, 180c using unlicensed band signals. In a non-standalone configuration, WTRU 102a, 102b, 102c can communicate/establish a connection with gNB 180a, 180b, 180c while simultaneously communicating/establishing a connection with another RAN such as eNode-B 160a, 160b, 160c. For example, WTRU 102a, 102b, 102c may implement dual connection (DC) principles to communicate substantially simultaneously with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c. In a non-standalone configuration, eNode-B 160a, 160b, 160c may act as a mobility reference point for WTRU 102a, 102b, 102c, and gNB 180a, 180b, 180c may provide additional coverage and/or capacity to serve WTRU 102a, 102b. 102s.

Each of the gNBs 180a, 180b, 180c may be associated with a specific cell (not shown) and may be configured to make radio resource management decisions, handover decisions, UL and/or DL user scheduling, network slicing support, dual connectivity , interaction between NR and E-UTRA, routing user plane data to user plane functional (UPF) block 184a, 184b, routing control plane information to access and mobility management functional block (AMF) 182a, 182b, and the like. As shown in FIG. 1D, gNB 180a, 180b, 180c can communicate with each other via the Xn interface.

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 optionally a data network (DN) 185a, 185b ). Although each of the above elements is shown as part of CN 115, it should be understood that any of these elements may be owned by and/or provided for use by an entity other than the CN operator.

The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may act as a management node. For example, AMF 182a, 182b may be responsible for authenticating users of WTRU 102a, 102b, 102c, supporting network slicing (e.g., handling different protocol data unit (PDU) sessions with different requirements), selecting a particular SMF 183a, 183b, registering area management, termination non-access layer signaling (NAS), mobility management, etc. Network slicing may be used at AMF 182a, 182b to configure CN support for WTRUs 102a, 102b, 102c based on the types of services used by WTRUs 102a, 102b, 102c. For example, different network slices can be established for different use cases, e.g., services based on enhanced reliability low latency communications (URLLC), services based on access to an enhanced (e.g., mass mobile) mobile broadband (eMBB) network, services for accessing machine-to-machine communications (MTC) and/or the like. AMF 162 may provide a control plane function for switching between RAN 113 and other RANs (not shown) that use other radio technologies such as LTE, LTE-A, LTE-A Pro, and/or non-3GPP access technologies, e.g. WiFi.

SMF 183a, 183b can be connected to AMF 182a, 182b in CN 115 via interface N11. SMF 183a, 183b can also be connected to UPF 184a, 184b in CN 115 via interface N4. The SMF 183a, 183b can select and control the UPF 184a, 184b, and configure the routing of traffic using the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating the IP address of the WTRU/UE, managing PDU sessions, managing policy enforcement and QoS, providing downlink data notifications, and the like. The PDU session type may be IP based, non-IP based, Ethernet based, etc.

The UPFs 184a, 184b may be connected to one or more gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRU 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate data exchange between WTRU 102a, 102b, 102c and IP-enabled devices. The UPFs 184, 184b may perform other functions such as packet routing and transmission, user plane policy enforcement, support for multi-channel PDU sessions, user plane QoS processing, downlink packet buffering, binding to support mobility, and the like.

CN 115 can facilitate data exchange with other networks. For example, CN 115 may include an IP gateway (eg, an IP multimedia subsystem (IMS) server) that acts as an interface between or communicates with CN 115 and PSTN 108. In addition, CN 115 may provide WTRU 102a, 102b, 102c with access to other networks 112, which may include other wired and/or wireless networks that are owned and/or provided for use by other service providers. In one embodiment, WTRU 102a, 102b, 102c may be connected to a local data network (DN) 185a, 185b via UPF 184a, 184b via an N3 interface to UPF 184a, 184b and an N6 interface between UPF 184a, 184b and DN 185a, 185b .

Taking into account FIG. 1A-1D and the corresponding descriptions of FIGS. 1A-1D one or more or all of the functions described herein in connection with one or more of: WTRU 102a-d, base stations 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a–c, AMF 182a–b, UPF 184a–b, SMF 183a–b, DN 185a–b and/or any other device(s) described in this document , may be implemented by one or more emulation devices (not shown). Emulation devices may be one or more devices configured to emulate one or more or all of the functions described herein. For example, emulation devices can be used to test other devices and/or to simulate network and/or WTRU functionality.

Emulation devices may be configured to implement one or more tests of other devices in a laboratory environment and/or in an operator network environment. For example, one or more emulation devices may perform one or more functions or all functions, where they are fully or partially implemented and/or deployed as part of a wired and/or wireless communications network to test other devices in the communications network. One or more emulation devices may perform one or more functions or all functions and are temporarily implemented/deployed as part of a wired and/or wireless communications network. The emulation device may be directly connected to another device to test and/or perform a test using wireless communication via a wireless communication channel.

One or more emulation devices may perform one or more functions, including all functions, without being implemented/deployed as part of a wired and/or wireless communications network. For example, emulation devices can be used in a test scenario in a test laboratory and/or in a non-deployed (eg, test) wired and/or wireless communications network to conduct testing of one or more components. One or more emulation devices may be test equipment. Emulation devices may use direct RF connections and/or wireless communications via RF circuitry (which may, for example, include one or more antennas) to transmit and/or receive data.

In certain exemplary embodiments, methods, system, device operations, functions, and/or procedures may be implemented to enable grouping of RACH preambles based on distance (e.g., using information related to propagation delay (e.g., (1) absolute propagation delay , (2) relative propagation delay, for example, which may be, but is not limited to, the difference in propagation delay relative to nadir, (3) the distance from the WTRU to its NAP, and/or (4) the distance from the WTRU to the nadir or NAP).

In certain exemplary embodiments, methods, system, device operations, functions and/or procedures may be implemented to enable selection of a RACH root sequence to determine the RACH preamble (e.g., using information related to propagation delay (e.g., (1) absolute delay propagation, (2) relative propagation delay, for example, which may be, but is not limited to, the difference in propagation delay relative to nadir, (3) the distance from the WTRU to its NAP, and/or (4) the distance from the WTRU to the nadir or NAP).

In certain exemplary embodiments, methods, system, device operations, functions and/or procedures may be implemented to enable the use of RA-RNTI, which is a function derived from or including information related to propagation delay.

Typical procedures for decoding random access response (RAR) as a function of distance

Satellite systems play a role (eg, an invaluable role) in making communications possible, for example, in places where the last mile of fiber optic cable or WTRU landline telephony is unsuitable. Satellite services can be considered as supporting services for terrestrial cellular and terrestrial communications systems. Satellite services have historically facilitated broadcast transmissions such as television and provided emergency critical services to the offshore oil platforms and shipping industries. Satellites can provide broadband (eg, true broadband) connectivity capabilities to terrestrial users in addition to terrestrial WTRU and fixed wireless systems. The volume of users using satellite services is limited to those (eg, only those) users who can afford the services or who have no other alternatives. For satellites to become a ubiquitous and competitive technology, the volume of supported users must increase, and unicast services must become more common in addition to existing broadcast services. As the number of users increases, the amount of data served can increase almost linearly.

Satellites can belong to one of several orbital classes. In the Low Earth Orbit (LEO) class, satellites typically range from approximately 400 to 2000 kilometers altitude, with an average altitude of approximately 700 kilometers. In the Medium Earth Orbit (MEO) class, satellites typically range from approximately 2,000 to 32,000 kilometers altitude, with an average altitude of approximately 20,000 kilometers. In geosynchronous orbit (GSO) or geostationary orbit (GEO), satellites can be quasi-fixed at approximately 36,000 kilometers. At higher altitudes, propagation delay and power budgets may be an issue (eg, primary issue), while at lower altitudes, Doppler effect and mobility may be an issue (eg, primary issue). At lower orbits, satellites experience atmospheric drag, and, according to Kepler's laws of planetary motion, the lower the orbital altitude, the higher the satellite's angular velocity.

For system sizing with good and/or acceptable link budgets, it is likely that commercial communications satellites could be either LEO or MEO in the medium term and at very high frequencies. For very high speed satellites, the Doppler effect can be very high and this can create problems with timing and fixation time. Satellite link budgets may be provided (eg, created) with high link power margins to overcome rain and/or other atmospheric aberrations that may occur during communications. Despite this, the signal-to-interference-noise ratio (SINR) experienced and/or measured on the downlink and/or uplink may be low (e.g., low enough) such that, for example, the circuits The highest modulation encodings used in satellite links can be several orders of magnitude lower than comparable ones in terrestrial communications systems. The long propagation delays associated with satellite links can be orders of magnitude greater than those observed in a terrestrial system. Long propagation delays can create problems in implementing efficient power control loops, which can result in satellite terminals and ground stations operating at incorrectly specified operating points.

Satellite links, although reliable, can suffer from high latency. Services that use TCP as a transport layer may be susceptible (eg, particularly susceptible) to latency, and performance may be degraded accordingly.

Typical procedures for establishing an RRC connection from idle mode

In fig. 2 is a diagram illustrating a typical RRC connection establishment procedure; As shown in FIG. 2, in RRC connection procedure 200, the WTRU 102 may enter an established RRC connection state after a 4-way signaling exchange. For example, at step 220, system information may be broadcast from the eNodeB, gNB 180, satellite S, base station (BS), ground station 310 B (eg, collectively referred to as network access point (NAP) 210). At step 230, WTRU 102 may perform DL synchronization and may read blocks of main information and/or system information to determine system viability. WTRU 102 may estimate the open loop transmit power to be applied and/or required after measuring the candidate cell reference signal or received pilot power and advertised DL transmit power. At step 240, the WTRU 102 may transmit message 1 (MSG1) to the NAP 210, which may include a RACH preamble (eg, using a masked and/or encrypted random access radio network temporary identifier (RA-RNTI). At step 250, the NAP 210 may detect RACH preamble and may determine an estimated timing advance (TA).At step 260, the NAP may transmit message 2 (MSG2) to the WTRU 102. The MSG2 message may include or may indicate, among other things, TA, power adjustment, UL grant, and/or temporary cellular radio network identifier (T-CRNTI).At step 270, WTRU 102 may transmit message 3 (MSG3) to NAP 210. MSG3 may include or may indicate an RRC connection request and WTRU ID. At step 280, NAP 210 may transmit message to WTRU 102 4 (MSG4) MSG4 may include conflict resolution (eg, a conflict resolution indication).

In certain exemplary embodiments, the RA-RNTI may be set as a function of, derived from, or may include a propagation delay-related parameter or information.

In certain exemplary embodiments, the preamble sent to MSG1 may be selected based on a propagation delay related parameter or propagation delay related information.

For example, NAP 210 may broadcast the CAZAC root sequence index and any rotation constraints that may apply in the cell. The WTRU 102 may generate multiple preambles (eg, 64 preambles) using the CAZAC root sequence and/or additional CAZAC root sequences, eg, depending on the cyclic shift constraints that may be applied in the cell. WTRU 102 may select one preamble from a superset of available preambles and may transmit the sequence (eg, in MSG1) at a power level determined by an open loop setting (eg, based on an open loop estimate). If the NAP 210 correctly received and evaluated the preamble, the NAP 210 can determine the amount of offset in the received preamble and the associated propagation delay. NAP 210 may convert the propagation delay into TA and may determine if WTRU 102 needs and/or needs to perform any power adjustment.

In fig. 3 is a diagram illustrating a typical NTN showing the propagation delay divergence within a narrow beam;

As shown in FIG. 3, in the case of the NTN 300, the NAP 210 may be in orbit from several hundred to several thousand kilometers (km) above the earth. For example, if NTN NAP 210 is determined to be in a circular orbit 3000 km above the earth, the one-way propagation delay is about 10 milliseconds to nadir on the ground. In fig. 3 D _A may be 3000 km and may be the distance to nadir, and terminal A (eg, WTRU 102 A and/or ground station 310 A) may be located at nadir. Terminal A may experience a one-way propagation delay of approximately 10 ms. If the minimum usable elevation angle is 45 degrees and terminal B (e.g., another WTRU 102 B and/or ground station 310 B) is at the edge of narrow beam 320 and meets an elevation angle θ (e.g., an elevation angle θ of 45 degrees), using the theorem Pythagoras, Terminal A 102A/310A and Terminal B 102B/310B can be separated by 3000 km. In this example, the curvature of the earth is ignored (e.g., not taken into account), and the earth can be considered a flat surface. The distance D _B between terminal B 102B/310B and NAP 210 may be 4242.6 km, and the one-way propagation delay over distance D _B is approximately 14.14 milliseconds. In narrow beam 320, there may be a significant propagation delay variance (e.g., ranging from 10 ms to 14.14 ms for the example shown in FIG. 3. This variance may increase as the minimum elevation angle decreases. Typically, satellites/NTN NAP 210 can have a usable lift angle of up to approximately 10 degrees.

In fig. 4 is a diagram illustrating a typical TA procedure.

As shown in FIG. 4, TA procedure 400 may include the WTRU 102 performing (eg, first performing) downlink synchronization with the BS and/or NAP 210 before performing network access (eg, any network access). For example, uplink and downlink radio frames may be synchronized based on propagation delay. The TA for WTRU 102 may be set to 2 times the propagation delay.

For example, in the uplink, BS/NAP 210 may wait to receive all transmissions from scheduled WTRUs 102 (e.g., from all scheduled WTRUs 102) for a particular slot (e.g., transmission time interval (TTI)), which will be time aligned, as shown in fig. 4. To compensate for propagation time differences between different WTRUs 102 in a coverage area (eg, a spot coverage area), the BS/NAP 210 may report timing advance (TA) information (eg, a TA value) to the WTRU 102 (eg, each WTRU 102). The TA value may represent a unit of time by which the WTRU 102 advances its uplink transmission such that its uplink frame arrives time-coordinated with other uplink transmissions from other WTRUs 102. Discrepancy (e.g., large divergence and/or divergence exceeding a threshold) propagation delay within narrow beam 320 may cause NAP 210 (eg, a satellite or other airborne device) to falsely detect a received preamble. Typical procedures for eliminating this false detection can be implemented by applying cyclic shift constraints. Such procedures may increase the processing load on the BS/NAP 210.

In certain exemplary embodiments, methods, systems, devices, operations, functions and/or procedures may be implemented to neutralize the propagation delay variance that would exist in such narrow beams 320, for example, allowing reliable TA estimation for the NTN BS/NAP 210.

Typical procedures for grouping RACH preambles based on distance

In fig. 5 is a diagram illustrating NTN nadir position estimation;

As shown in FIG. 5, in the NTN 500, a narrow beam 510 (e.g., round or elliptical with low eccentricity) can be divided into several concentrically enclosed sub-narrow beams 520, 530, 540. The center of the narrow beam is the nadir of the satellite (for example, directly below the BS/NAP 210). The minimum propagation delay between satellite/BS/NAP 210 and WTRU 102/ground station 310 within narrow beam 510 occurs at the center (eg, nadir N) of narrow beam 510 (eg, nadir N of satellite/NAP 210 (located at S).

The minimum angle of elevation θ ₁ in Fig. 5 may be a design parameter and may be known to satellite/NAP 210 and WTRU 102 in narrow beam 510. The minimum elevation angle may be signaled to WTRU 102 over the air interface, for example, in addition to or through system information. The satellite position S may be estimated by the WTRU 102 based on information broadcast in the system information. For example, the absolute transmission time of a particular block of system information corresponding to {SFN, SF} in which it is transmitted may be included in the system information as Coordinated Universal Time (UTC). It is assumed that, based on the difference between the received and transmitted timestamps, the WTRU 102 can estimate the propagation delay to the satellite/NAP 210 at position S. Of two or more such transmissions from the satellite/NAP 210 at positions S(t), S(t+∆t ), S(t+2∆t), … S(t+2n∆t) (e.g., where n is an integer), the WTRU 102 may determine the distance and/or trajectory of the satellite/NAP 210 based on periodic reception of such information . In certain exemplary embodiments, satellite/NAP 210 may broadcast its GNSS coordinates, for example, periodically as part of system information.

WTRU 102 at an arbitrary position A within narrow beam 510 can estimate the position S of a satellite (e.g., NAP 210) and distance D_A to satellite position S/NAP 210 and/or corresponding internal angle θ₂that the WTRU 102 creates with the satellite/NAP 210. Since point N is the nadir of the satellite/NAP 210 (eg, which is the perpendicular from point S to point N), an additional angle θ can be determined₃. When determining angles θ₂and/or θ_3, which point A forms with S and hypotenuse D_A (which may be a propagation distance), the distance between point A and N can be determined, and/or distance from S and N, D_min. Appropriate propagation delays can be determined to cover distances D_min and/or D_A.

For example, it is contemplated that for values (eg, all continuous values) there may be a one-way propagation delay discrepancy between the distance _Dmin and the distance _Dmax . If two WTRUs 102, one at point N and the other at point B, select (eg, through a uniform and random selection procedure) and transmit an identically offset CAZAC cyclic sequence, the NAP 210 at position S may falsely detect one of the preambles due to the large discrepancy between these distances (for example, distance D _min and distance D _max ). The same result could be true for any two WTRUs 102, one in a first position (e.g., position N) within narrow beam 510, and the other at any arbitrary position A within narrow beam 510. Without loss of generality, there may be a variable issue value (eg, variable propagation delay synchronization) for any two or more WTRUs 102 at arbitrary positions A, A ¹ , etc. within a narrow beam 510. The problem may be less pronounced when the distance between A, A ¹ is relatively small (eg, less than a threshold difference in propagation delay), and the problem may be more pronounced when the distance between A and A ¹ is relatively large ( for example, greater than the threshold difference in propagation delay).

In certain exemplary embodiments, WTRU 102 at position A may be instructed to determine its relative distance to point N and, depending on the distance to point N, WTRU 102 may select (eg, may force selection) from a subset of available preambles. For example, the difference in propagation delay, for WTRU 102 at point A compared to the minimum propagation delay D _min , can be represented in Equation 1 as follows.

(1)

The total set of preambles {P} available in narrow beam 510 can be divided into T orthogonal sets corresponding to the properties presented in equations 2 and 3 as follows.

… (2)

… (3)

The size of each subset may be different and may or may not be equal (for example, the number of preambles in one subset _P1 may be equal to, greater than, or less than P1 ₎ . It is assumed that P ₁ is a subset or own subset of P, for example, some of the subsets may not be used by BS/NAP 210 if BS/NAP 210 selects/defines and/or may be reserved for special use. WTRU 102 may be signaled to select/specify a preamble from a specific subset , I based on the formula presented in Equation 4.

… (4)

WTRU 102 may estimate distance D _min and/or distance D _A without ambiguity (eg, any ambiguity). The propagation delay difference _δA can be estimated based on Equation 1. Depending on the threshold value of the propagation delay difference _δA, the WTRU 102 may select a preamble using Equation 4 and may transmit the NTN preamble (eg, NAP 210). In certain exemplary embodiments, because the NTN knows that the WTRU 102 must select a preamble from a subset of preambles (e.g., a randomly selected preamble from only the subset of preamble data associated with WTRU 102 position A in narrow beam 510) based on its relative position to nadir ( eg point N), there is no confusion regarding the effect of differential propagation delay in the received offset sequence.

In one embodiment, WTRU 102 may be pre-configured to automatically determine preamble subsets and associated propagation delay difference thresholds unless explicitly signaled by gNB 180/NAP 210 (eg, by a network entity). For example, a procedure may be implemented to allow the WTRU 102 to have subsets of preambles, and the associated thresholds may be preconfigured in mobile equipment (ME) and/or universal subscriber identity modules (USIMs). The procedure may allow the WTRU 102 to be configured (eg, on the WTRU 102) by a network entity (eg, gNB 180 and/or NAP 210) by the application layer over any communications media. The gNB 180 may signal a parameter, such as PREAMBLESET_INDICATOR, through system information, or through dedicated signaling to the WTRU 102. The PREAMBLESET_INDICATOR may provide instructions to the WTRU 102 on how to determine preamble subsets and associated thresholds. PREAMBLESET_INDICATOR can be, for example, a scalar value encoding an integer or a bitstring, although other formats are also possible and not excluded.

As one example, PREAMBLESET_INDICATOR = 1 may instruct the WTRU 102 to select procedure #{1} in its stored memory. Procedure #{1} can preliminarily determine the division of 64 preambles into 8 equal sets {P ₁ , P ₂ ,... P ₈ }, each with 8 preambles. Procedure#{1} can correlate {P ₁ , P ₂ ,... P ₈ } with thresholds {THR1=500 µs, THR2=900 µs,... THR8=4800 µs}. The definition included and/or contained in procedure#{1} may be known in advance in the WTRU 102 and gNB 180/NAP 210. The WTRU 102 may be pre-configured with U procedures (eg, U different procedures), procedure#{1 , 2, … U}, with each procedure#{I}, I is a specific method for generating sets of preambles and obtaining corresponding delay difference thresholds. In certain exemplary embodiments, the values selected for the thresholds may correspond to the distances of the WTRU 102 from nadir. One skilled in the art will appreciate that any threshold THR1, THR2...THRN may correspond to a variety of values according to the propagation delay range associated with the WTRU located within the narrow beam. The THR1, THR2...THRN thresholds may vary depending on the satellite/NAP's orbital/airborne trajectory over the earth's surface and beam coverage.

Typical procedures for selecting a RACH root sequence based on distance

In certain exemplary embodiments, the gNB 180/NAP 210 may select and/or determine the need to apply different RACH root sequences to the WTRU 102 based on the location of the WTRU 102. If the gNB 180/NAP 210 selects/determines the need to apply T RACH root sequences with root indices sequences {R ₁ , R ₂ ,..., R _T }. The WTRU 102 may be signaled to select a root sequence index , I T based on the formula presented in Equation 5.

(5)

WTRU 102 may estimate distance D _min , distance D _{A ,} and/or propagation delay (eg, propagation delay difference) δ _A . Depending on the propagation delay difference threshold _δA, WTRU 102 may select a RACH root sequence index by applying Equation 5.

After selecting a root sequence index, WTRU 102 may generate a CAZAC sequence of length Q. For example, Q may be set to 837 for NR and/or LTE. The WTRU 102 can generate 64 cyclically shifted preambles with a given root. The WTRU 102 may uniformly and randomly select a preamble and may transmit the selected NTN 300/500 preamble. The WTRU 102 may exclude from the 64 preambles any preambles that are reserved for dedicated use. Preambles reserved for dedicated use may be signaled to the WTRU 102 by the gNB 180/NAP 210, for example, in system information or via dedicated RRC signaling. gNB 180/NAP 210 may determine and/or select the application of cyclic shift restrictions, depending on the situation, for various exemplary embodiments.

In certain exemplary embodiments, additional root sequence indices may be determined, for example, based on the root sequence index of the primary RACH , I T selected in Equation 5. For example, the WTRU 102 may be pre-configured to automatically determine a plurality of RACH root sequences and associated propagation delay thresholds if not explicitly communicated by the gNB 180/NAP 210 signal. The primary RACH root sequence index may (e.g., may always) be transmitted via the WTRU 102 signal. The WTRU 102 may be pre-configured by a procedure (eg, pre-configured) in the ME/USIM regarding how to determine a plurality of RACH root sequences and/or associated thresholds. The procedure may be configured in the WTRU 102 by the network via the application layer via any communication means. The gNB 180/NAP 210 may signal a parameter, such as RSISET_INDICATOR, via system information and/or dedicated signaling to the WTRU 102. The RSISET_INDICATOR parameter may provide instructions to the WTRU 102 on how to determine a plurality of RACH root sequences and associated thresholds. The RSISET_INDICATOR parameter, for example, can be a scalar value encoding an integer or a bit string, although other formats are possible and not excluded.

As one example, RSISET_INDICATOR = 1 may indicate that the WTRU 102 should select procedure #{1} from the stored memory of the WTRU 102. Procedure #{1} may predefine a set of 4 RACH root indices as follows: {R ₁ , R ₁ + A, R ₁ +B, R ₁ +C}, where R ₁ is the root sequence index of the primary RACH signaled by the gNB 180/NAP 210 system information, and the integers {A, B, C} are predefined for the procedure #{1}. Procedure#{1} can correlate {R ₁ , R ₂ , _R3 , R ₄ } with thresholds {THR1=500 µs, THR2=900 µs,... THR4=2000 µs}. The definition included and/or contained in procedure #{1} may be known in advance in the WTRU 102 and gNB 180/NAP 210 (eg, BS). The WTRU 102 may be preconfigured with U procedures (e.g., U different procedures), procedure#{1, 2, ... U}, with each procedure#{I}, I is a particular method for generating sets of RACH root sequences and/or obtaining corresponding delay difference thresholds.

Typical procedures for determining sub-narrow beams

Sub-narrow beams 520, 530 and 540 (e.g., tree rings) (e.g., can be determined and/or specified based on differential propagation delays δ estimated using the formula in Equation 1 (and/or using a formula that also takes into account the curvature of the Earth and/or the height of the WTRU 102) Depending on the exact differential propagation delay δ and/or associated threshold settings, the WTRU 102 may select a plurality of RACH preambles and/or a RACH root sequence.

In certain exemplary embodiments, satellite/NAP 210 may apply differential distance thresholds. For example, WTRU 102 A may have a GNSS receiver allowing it to estimate its position (X _A , Y _A ) on a coordinate plane (e.g., where (X, Y ) refer to latitude and longitude). The nadir of the satellite/NAP 210 can be estimated by WTRU 102 A (eg, at location A) as (X _N , Y _N ) using the procedures described herein. Distance refers to the distance between WTRU 102 A and nadir N of the satellite/NAP 210. The satellite/NAP 210 may select and/or determine whether to define sub-spot beams 520, 530 and 540 based on the differential distance using nadir N as a reference point. In this case, Equation 4 can be changed to Equation 6, which is presented below.

… (6)

where is the specific subset , I previously defined, and , I represent distance thresholds relative to nadir. For example, if the satellite selects and/or determines the need to assign different root sequences to sub-bottom beams (eg, sub-bottom beams 520, 530, and 540), Equation 5 may be modified to Equation 7, which is presented below.

… (7)

In fig. 6 is a general flow diagram illustrating a typical procedure for selecting RACH preambles based on distance in an NTN. Certain procedures described herein use portions of this exemplary procedure 600. As shown in FIG. 6, a typical procedure may include, at block 605, the WTRU 102 receiving preamble subsets, root sequence sets, propagation delay value thresholds (eg, differential propagation delay thresholds) from the ME and/or USIM, provided that such information is broadcast to SI and/or via RRC signal. In an alternative embodiment, at block 610, the WTRU 102 may apply default/specified information associated with preamble subsets, root sequence sets, propagation delay thresholds, provided that such information is not broadcast in the SI and/or via the RRC signal.

At block 615, the WTRU may read the absolute transmission time (TX) of the SI in UTC. At block 620, the WTRU 102 may determine the position of the satellite/NAP 210 and/or the nadir of the satellite/NAP 210. At block 625, the WTRU 102 may determine the current position of the WTRU 102. At block 630, the WTRU 102 may determine any of the following: (1) relative distance ( e.g., from WTRU 102 to satellite/NAP 210 or from WTRU 102 to nadir N) associated with satellite/NAP 210, and/or (2) relative propagation delay associated with satellite/NAP 210 based on absolute TX time. At block 635, provided that the WTRU 102 determines the relative delay, the WTRU 102 may determine the differential propagation delay. At block 640, provided that the WTRU 102 determines the relative position, the WTRU 102 may determine the nadir distance. At block 645, WTRU 102 may determine whether to select subsets of preambles or sets of root sequences. At block 650, subject to the selection of preamble subsets at block 645, WTRU 102 may compare: (1) the determined propagation delay or differential propagation delay with propagation delay thresholds; and/or (2) specific relative distance with distance thresholds. Based on this comparison, WTRU 102 may select a subset of preambles. The WTRU 102 may randomly select a preamble from a selected subset of preambles.

At block 655, subject to the selection of root sequence sets at block 645, WTRU 102 may compare: (1) the determined propagation delay or the determined differential propagation delay with propagation delay thresholds; and/or (2) specific relative distance with distance thresholds. Based on this comparison, the WTRU 102 may select a plurality of root sequences. The WTRU 102 may: (1) randomly select a preamble from a selected set of root sequences; or (2) randomly select a preamble from a specific subset of preamble sets (the specific subset is selected based on, for example, information related to propagation delay). At block 660, the WTRU 102 may initiate a RACH procedure and may enter connected mode. At block 665, WTRU 102 may receive RRC signals: Processing may proceed to 605 to establish one or more additional connections.

Typical procedure for masking a physical RACH (PRACH) based on relative distance (e.g. nadir distance)

The gNB 180/NAP 210 can apply multiple RACH elements per duty cycle. For example, gNB 180/NAP 210 may apply a total of R possible RACH elements, eg, every duty cycle (eg, every 20 ms, evenly or unevenly distributed within a 20 ms duty cycle). In some embodiments, gNB 180/NAP 210 may limit access for WTRU 102 in a particular geographic area within narrow beam 510 to one or more possible RACHs, but not all possible R possible RACHs. More generally, gNB 180/NAP 210 may configure limited access for WTRU 102 in a specific geographic area (e.g., based on propagation delay (e.g., calculated δ as in Equation 1, or based on nadir distance N within a narrow beam) to one or more RACH resources within all possible R RACH resources.

For example, gNB 180/NAP 210 may determine that WTRU 102 within distance DistTHR ₁ from nadir may apply the 1st possible RACH (e.g., only the 1st possible RACH) within a duty cycle, WTRU 102 within distance DistTHR ₂ from nadir and further than DistTHR ₁ from nadir may apply the 2nd possible RACH (eg, only the 2nd possible RACH) within the duty cycle, etc. In another example, gNB 180/NAP 210 may determine that WTRU 102 within distance DistTHR ₁ from nadir may apply a given RACH resource with a particular aspect of the frequency domain (e.g., allocation of a particular PRB, a particular f_id, and/or a particular portion of bandwidth), and WTRUs 102 within distance DistTHR ₂ from nadir and further than DistTHR ₁ from nadir may apply a RACH resource with a different frequency domain aspect, etc. Similar to the detailed description above, the gNB 180/NAP 210 may apply distance thresholds ψ (eg, differential or absolute distance thresholds). The WTRU 102 A may have a GNSS receiver allowing the WTRU 102 A to estimate its position (X _A , Y _A ) on a coordinate plane, where (X, Y) refers to the latitude and longitude of the WTRU 102 A. The nadir of the S/NAP satellite 210 may be estimated by WTRU 102 A to be (X _N , Y _N ) using the procedures described herein. Distance refers to the distance between WTRU 102 A and satellite/NAP 210 nadir N.

gNB 180/NAP 210 may apply one or more PRACH masks to a duty cycle and may associate masks (eg, each mask) with distance thresholds (eg, a range of distance thresholds), and may signal ranges of distance thresholds via SI, RRC signaling and/or multicast. WTRU 102 A may select possible RACH based on distance WTRU 102 A relative to nadir. An example is presented in Equation 8 as follows.

… (8)

In an alternative embodiment, the possible RACH may be as represented in Equation 9 as follows:

… (9)

Typical RAR decoding procedure based on relative distance (e.g. nadir distance)

In certain exemplary embodiments, the RA-RNTI may be made dependent on (eg, may be based on) a propagation delay-related parameter/information, such as the distance from the WTRU 102 to nadir. The formula for calculating RA-RNTI may take into account (eg, include and/or be a function of) distance or differential distance as part of the calculation. For example, the RA-RNTI of a cell may be a function (subframe index, where ), (index of the specified PRACH within this subframe, where ), differential propagation delay and/or differential distances ( ) An example of a destination could be:

where f represents any function.

In an example, the RA-RNTI formula could be composed (e.g., more generally composed) as follows in equation 10 or 11:

… (10)

… (eleven)

The WTRU 102 may apply the appropriate RA-RNTI for RAR decoding. Distance encoding, as part of the RA-RNTI, may be useful for the gNB 180/NAP 210 to refer to a given WTRU 102 when preamble collisions occur, such as when a single preamble/multiple preambles are found in more than one sub-narrow beam 520, 530, and 540.

As shown in FIG. 5, any WTRU 102 in the innermost sub-narrow zone or ring 540 (e.g., WTRU 102 in position N or near nadir) can expect the physical downlink control channel (PDCCH) of WTRU 102 in position N to be encrypted by , and any WTRU 102 in the outermost sub-narrow zone or ring 520 (e.g., WTRU 102 at or near position B) can expect the PDCCH of WTRU 102 at position B to be encrypted by , wherein . The WTRU 102 in the innermost sub-narrow zone/ring 540 may use to decode its PDCCH, and the WTRU 102 in the outermost subarea/ring 520 may use to decode its PDCCH. This approach is not expected to require the use of different preamble sequences and/or different sets of preambles by the WTRU 102 in different rings. In certain exemplary embodiments, a plurality of sequences may be shared by a WTRU 102 (e.g., by all WTRUs 102 in a narrow beam (e.g., similar to how they are shared by a WTRU 102 in a terrestrial cell). In other exemplary embodiments, the plurality of sequences may be different for different portions of narrow beam 510. In certain designs, WTRU 102 may need to determine (eg, only determine) propagation delays or differential propagation delays _δA (as in Equation 1) or distances or differential distances to find out/determine which RA-RNTI may be used and/or may need to be used by the WTRU 102. Such a scheme may reduce time loss due to collisions since the PDCCH may be encrypted with different RNTIs for the WTRU 102 in different rings/ring areas, e.g. to avoid conflicts.

Although the narrow beam zones 510 are divided into sub-narrow zones 520, 530 and 540 in the form of various rings, annular zones, other divisions are possible, such as sectional rings. For example, the outermost sub-narrow zone 520 may be further divided into any number of sections (eg, half sections, quarter sections, or sixth sections, among others). A different RNTI may be used to encrypt the PDCCHs of WTRUs located in a particular section. The division of narrow beam 510 may be based on the number of WTRUs estimated for a particular division, and may be semi-static or dynamically adjusted via broadcast information and/or RRC signals.

In certain exemplary embodiments, WTRU 102 may determine whether RAR transmission (eg, MSG2) is applicable based on the contents of the RAR. For example, the contents of the RAR may include a target distance or a differential distance, and WTRUs 102 located within such a geographic area may be considered applicable. This may be an alternative to changing the RA-RNTI format, and may target specific WTRUs 102 within a subset of narrow beam coverage 510.

Typical RACH Procedure for Correcting Incorrect Differential Propagation Delay/Distance Estimation

If the WTRU 102 incorrectly calculates and/or incorrectly determines propagation delays/distance (e.g., differential propagation delays/distance) ( ), an incorrect sequence of preambles may be selected. For example, the WTRU 102 may select a preamble from a first set of preambles (and/or a first root sequence) belonging to and/or corresponding to a first partition (e.g., the first region 540 of narrow beam 510, whereas the WTRU 102 would have selected a second preamble from a second set of preambles , due to an incorrect calculation of propagation/distance delays (e.g., differential propagation delay/distance) (e.g., WTRU 102 is in a different, second partition (e.g., second region 530 of narrow beam 510) rather than in a first partition, e.g., in another geographic area that corresponds to the second set of preambles) Since the RA-RNTI may depend on propagation/distance delays (e.g., differential propagation/distance delay), the WTRU 102 may perform any of the following:

1) without waiting for RAR (which corresponds to the RACH sequence transmitted from the first preamble set) in the RAR window, WTRU 102 can retransmit MSG1 with a sequence from the correct preamble set (eg, from the second preamble set);

2) WTRU 102 may ignore RAR that may have been received using the RNTI corresponding to the first set of preambles, and may not continue to (i) monitor the PDCCH for the selected preamble (and/or RA-RNTI) for which the nadir distance was incorrectly estimated /propagation delay, and/or (ii) sending MSG3 to transmit this preamble; and/or

3) WTRU 102 may monitor the RAR corresponding to a sequence selected from the second set of preambles (eg, a sequence from the correct set of preambles) and may proceed to MSG3 and MSG4 after receiving MSG2. (e.g., in some embodiments, a two-stage RACH may be possible in which MSG1/MSG3 may be sent to the WTRU 102 simultaneously or substantially simultaneously and MSG2/MSG4 may be received by the WTRU 102 simultaneously or substantially simultaneously. Among other things, the procedure may continue in the normal manner with a preamble selected from the correct set (eg, the second preamble set). For example, in the case of a 2-stage RACH, WTRU 102 may transmit MSG1+MSG3 of the second preamble set and may ignore MSG2+MSG4 of the first preamble set. Instead The WTRU may wait MSG2+MSG4 for the second set of preambles.

The WTRU 102 may perform any of the actions described above provided that a certain period (or timer) has not elapsed since the original preamble was transmitted (eg, a preamble for which the nadir distance and/or propagation delay was incorrectly estimated).

In certain exemplary embodiments, the WTRU 102 may assume a minimum usable elevation angle.

In certain exemplary embodiments, the WTRU 102 may estimate the propagation delay to/from the satellite relative to its current position.

In certain exemplary embodiments, WTRU 102 may estimate the position of satellite S and/or NAP 210 relative to its current position.

In certain exemplary embodiments, WTRU 102 may estimate the nadir reference propagation delay of satellite S.

In certain exemplary embodiments, WTRU 102 may determine the difference between the propagation delay from satellite S to the satellite's current position and/or the propagation delay from satellite S to the nadir of the satellite.

In certain exemplary embodiments, WTRU 102 may receive, through system information, a number of preambles and/or associated propagation delay difference thresholds.

In certain exemplary embodiments, WTRU 102 may receive, through dedicated RRC signaling, a number of preambles and/or associated propagation delay difference thresholds.

In certain exemplary embodiments, the number of preamble sets and/or associated propagation delay difference thresholds may be different when received via system information (SI) and via dedicated signaling.

In certain exemplary embodiments, WTRU 102 may receive multiple preambles and/or associated propagation delay difference thresholds applicable for use in any of the following: (1) sleep mode (eg, sleep mode only); (2) connected mode; or (3) both.

In certain exemplary embodiments, WTRU 102 may apply a default plurality of preambles and/or associated propagation delay mapping configuration if the plurality of preambles and/or associated propagation delay mapping configuration are not received via SI and/or dedicated signaling.

In certain exemplary embodiments, WTRU 102 may be configured in the ME and/or USIM to determine whether to apply a default set of preambles and/or associated propagation delay difference mapping.

In certain exemplary embodiments, the WTRU 102 may be signaled via the SI whether to apply the default preamble set and/or the associated default propagation delay difference mapping.

In certain exemplary embodiments, WTRU 102 may configure one or more procedures in the ME and/or USIM to execute a circuit for determining default preamble sets and/or associated propagation delay difference mapping.

In certain exemplary embodiments, the WTRU 102 may receive a parameter (eg, a PREAMBLESET_INDICATOR parameter) through the SI and/or through dedicated signaling to determine which preconfigured procedure to execute for determining default preamble sets and/or associated propagation delay difference mapping.

In certain exemplary embodiments, WTRU 102 may select a subset of preambles, for example, by comparing the estimated propagation delay difference with propagation delay thresholds transmitted via gNB 180/NAP 210 signals.

In certain exemplary embodiments, the WTRU 102 may select a subset of preambles, for example, by comparing the estimated propagation delay difference with the propagation delay thresholds provided by default from the ME/USIM.

In certain exemplary embodiments, WTRU 102 may receive via SI a plurality of RACH root sequences consisting of one or more root sequence indices and/or associated propagation delay thresholds.

In certain exemplary embodiments, WTRU 102 may receive, via dedicated RRC signaling, a plurality of RACH root sequences consisting of one or more root sequence indices and/or associated propagation delay thresholds.

In certain exemplary embodiments, a plurality of RACH root sequences consisting of or including one or more root sequence indices and associated propagation delay difference thresholds may be different when received via SI and via dedicated signaling communications.

In certain exemplary embodiments, WTRU 102 may receive a plurality of RACH root sequences consisting of one or more root sequence indices and/or associated propagation delay thresholds applicable for use in idle mode only, connected mode only, or both.

In certain exemplary embodiments, the WTRU 102 may employ a set of default RACH root sequences consisting of or including one or more root sequence indices and/or an associated propagation delay difference mapping configuration if not received by the SI.

In certain exemplary embodiments, WTRU 102 may be configured, for example, by an ME and/or USIM, to determine whether to apply a set of default RACH root sequences consisting of or including one or more root sequence indices and/or associated relating propagation delay differences. In certain exemplary embodiments, the WTRU 102 may be signaled by the SI whether to apply a set of default RACH root sequences consisting of or including one or more root sequence indices and/or an associated propagation delay difference mapping.

In certain exemplary embodiments, the WTRU 102 may be configured with one or more procedures using either the ME or the USIM to perform a circuit for determining multiple RACH root sequences and/or associated propagation delay difference correlation.

In certain exemplary embodiments, WTRU 102 may be configured with one or more procedures for generating a plurality of RACH root sequences consisting of or including one or more root sequence indices.

In certain exemplary embodiments, WTRU 102 may select a RACH root sequence index from a plurality of RACH root sequences, for example, by comparing the estimated propagation delay difference with propagation delay thresholds transmitted via gNB signals. In certain exemplary embodiments, WTRU 102 may select a RACH root sequence index from a plurality of RACH root sequences, for example, by comparing the estimated propagation delay difference with the propagation delay thresholds provided by default ME/USIM.

Typical RACH Procedure for Airborne WTRUs

The above embodiments naturally extend to aircraft (eg, unmanned aerial vehicles). More generally, nadir N does not have to be on the surface of the earth (as described above), but can be at an arbitrary height, the latter being transmitted via gNB 180/NAP 210 signals and/or can be pre-configured in the USIM. For example, the one or more transmitted altitudes may represent the maximum altitude at which the unmanned aerial vehicle can operate and/or the altitude at which the unmanned aerial vehicle is currently operating. Based on one or more signaled altitudes, the parameter D _min can be calculated when the position of the satellite S is known, as described above. In certain exemplary embodiments, gNB 180/NAP 210 may signal D _min through one or more SI messages and/or other means such that any WTRU 102 (air/ground) can implement equation (1) to calculate δ. The rest of the preamble selection procedure follows similar techniques described previously in Equation 4 or Equation 5.

In fig. 7 is a flowchart illustrating a typical RACH execution procedure.

As shown in FIG. 7, exemplary procedure 700 may include, at block 710, the WTRU 102 receiving sets of preambles or root sequences associated with differential propagation delay thresholds. At block 720, WTRU 102 may determine the propagation delay between WTRU 102 and NAP 210. At block 730, WTRU 102 may compare the determined propagation delay to differential propagation delay thresholds. At block 740, the WTRU 102 may select an appropriate preamble set or root sequence. At block 750, WTRU 102 may perform a RACH procedure.

In fig. 8 is a flowchart illustrating another exemplary procedure for selecting RACH preambles based on parameters/information related to propagation delay.

As shown in FIG. 8, exemplary procedure 800 may include, at block 810, the WTRU 102 receiving from NAP 210 a plurality of preambles and corresponding propagation delay-related thresholds. At block 820, WTRU 102 may determine information related to propagation delay information related to the distance between the WTRU and the NAP or location within the coverage area of NAP 210. At block 830, WTRU 102 may select a subset of preambles from the plurality of preambles based on the determined delay-related information distribution. At block 840, WTRU 102 may randomly select a preamble from a selected subset of preambles. At block 850, WTRU 102 may send a randomly selected preamble to the NAP.

In certain exemplary embodiments, WTRU 102 may select a root sequence, wherein selecting a subset of preambles includes selecting a subset of preambles corresponding to the selected root sequence.

In certain exemplary embodiments, the WTRU 102 may receive network access information from the NAP; and can initiate network access using network access information.

In certain exemplary embodiments, WTRU 102 may determine a random access radio network temporary identifier (RA-RNTI), which is a function of, derived from, or includes at least information related to propagation delay, and may decode network access information included in a random access response (RAR), using a specific RA-RNTI.

In certain exemplary embodiments, NAP 210 may be included in a satellite and/or may be part of a non-terrestrial network.

In certain exemplary embodiments, information related to propagation delay may include any of the following: (1) the distance from the WTRU 102 to the NAP 210; (2) the distance from WTRU 102 to nadir N in NAP 210; (3) the angle between a line passing between WTRU 102 and NAP 210 and a line passing between Nadir N of NAP 210 and NAP 210; or (4) propagation delay or differential propagation delay of the signal sent between WTRU 102 and NAP 210.

In certain exemplary embodiments, the WTRU 102 may receive, via broadcast information or dedicated signaling, a random access configuration, including a plurality of thresholds related to propagation delay, and any of the following: (1) location information indicating the location of the NAP 210; or (2) path information indicating the path that the NAP 210 should traverse.

In certain exemplary embodiments, the WTRU 102 may select one orthogonal subset of the plurality of preambles that corresponds to a particular portion of the NAP 210 coverage.

In certain exemplary embodiments, each portion of the NAP cover 210 may correspond to a correspondingly different subset of the plurality of preambles.

In certain exemplary embodiments, each orthogonal subset of the plurality of preambles may be any of the following: (1) preconfigured with appropriate thresholds related to propagation delay; or (2) explicitly communicated via NAP 210 signals.

In certain exemplary embodiments, a selected subset of the preamble set may correspond to an annular or oval annular region or a portion of an annular or oval annular region of a coverage area. NAP coverage is assumed to be the volume of coverage that can correspond to a ground surface (eg, the Earth's surface) for a general definition of coverage area.

In certain exemplary embodiments, the WTRU 102 may determine a sub-area of the coverage area of the NAP 210 and may select a subset of preambles associated with the sub-area of the coverage area by, for example, any of the following: (1) comparing a determined value of information related to propagation delay with one or more thresholds related to propagation delay; or (2) by means of a reference table associated with a certain value of information related to the propagation delay.

In certain exemplary embodiments, the WTRU 102 may receive from the NAP 210 via system information any of the following: (1) GNSS coordinates periodically or (2) a usable elevation angle of the NAP 210.

In certain exemplary embodiments, WTRU 102 may receive constraint information from NAP 210 and, in accordance with the constraint information, may constrain any of the following: (1) one or more RACH elements to send a randomly selected preamble to NAP 210; or (2) the number of cyclic shifts associated with the RACH root sequence applied by the WTRU 102.

In certain exemplary embodiments, the WTRU 102 may limit a randomly selected preamble to a first RACH element or a first plurality of RACH elements, provided that the WTRU 102 is located in any of the following: (1) a first coverage area of the NAP 210; (2) first nadir distance range N NAP 210; (3) a first range of distances to NAP 210 or (4) a first range of propagation delays to NAP 210.

In certain exemplary embodiments, the WTRU 102 may limit a randomly selected preamble to a second RACH element or a second plurality of RACH elements, provided that the WTRU 102 is located in any of the following: (1) a second coverage area of the NAP 210; (2) second nadir distance range N NAP 210; (3) a second range of distances to NAP 210 or (4) a second range of propagation delays to NAP 210.

In certain exemplary embodiments, the WTRU 102 may determine the altitude of the WTRU such that information related to propagation delay can be further based on the determined altitude.

In certain exemplary embodiments, the WTRU 102 may determine the altitude of the WTRU 102 and may determine information related to propagation delay as a function of the determined altitude, provided that the determined altitude exceeds a threshold.

In certain exemplary embodiments, the WTRU 102 may determine the type of the WTRU 102 and may determine information related to propagation delay based on the height of the WTRU 102, provided that the determined type is a first type of WTRU 102. For example, the first type of WTRU 102 may be an unmanned aircraft and/or aerial device.

In certain exemplary embodiments, each preamble of a selected subset of preambles may be: (1) a round-robin version of the CAZAC root sequence.

In certain exemplary embodiments, the selected preamble may be a random access preamble (RAP) sent in a RAP message, and the received network access information may be received in a random access response (RAR) message that is sent in response to the RAP message.

In certain exemplary embodiments, the network access information may include a timing advance for the WTRU 102 and/or a power command for the WTRU 102.

In fig. 9 is a flow diagram illustrating another exemplary procedure using a Random Access Radio Network Temporary Identifier (RA-RNTI), which is a function of, includes, or is derived from a parameter/information related to propagation delay.

As shown in FIG. 9, exemplary procedure 900 may include, at block 910, determining to the WTRU 102 information related to propagation delay associated with a distance between the WTRU 102 and the NAP 210 or a location within the coverage area of the NAP 210. At block 920, the WTRU 102 may receive a random response access control (RAR) masked with a Random Access Radio Network Temporary Identifier (RA-RNTI), which is a function of, derived from, or includes at least certain information related to propagation delay. At block 930, WTRU 102 may determine the RA-RNTI based on certain propagation delay-related information. At block 940, WTRU 102 may decode RAR using the determined RA-RNTI.

In certain exemplary embodiments, WTRU 102 may send a message to a network entity (eg, NAP 210) with a timing advance and power level derived from the information indicated by the RAR.

In certain exemplary embodiments, the WTRU 102 may send to the network entity 210 a random access preamble (RAP) that may indicate the RA-RNTI associated with the WTRU 102.

In certain exemplary embodiments, WTRU 102 may select a subset of RAPs from a plurality of RAPs based on certain information related to propagation delay, and may randomly select a RAP from the selected subset of RAPs.

In certain exemplary embodiments, RAR may be masked or encrypted by RA-RNTI, and RA-RNTI may be a function of propagation delay or differential propagation delay and any of the following: (1) subframe index; or (2) Physical Random Access Channel (PRACH) resource index.

In certain exemplary embodiments, WTRU 102 may compare the RA-RNTI associated with the received RAR with the RA-RNTI determined based on certain propagation delay-related information as a result of the RA-RNTI comparison and may determine whether the received RAR is intended for WTRU 102 using the result of the RA-RNTI comparison.

In certain exemplary embodiments, the WTRU 102 may decode the received RAR, provided that the RAR is intended for the WTRU 102 in accordance with the result of the RA-RNTI comparison.

In certain exemplary embodiments, information related to propagation delay includes any of the following: (1) the distance from the WTRU 102 to the NAP 210; (2) the distance from WTRU 102 to nadir N in NAP 210; (3) the angle between a line passing between WTRU 102 and NAP 210 and a line passing between Nadir N of NAP 210 and NAP 210; or (4) propagation delay of a signal sent between WTRU 102 and NAP 210.

The terms "differential propagation delay" and "propagation delay differences" can be used interchangeably herein and essentially refer to the propagation delay associated with a WTRU in a narrow beam, which may exceed the minimum propagation delay (e.g., associated with nadir N in a narrow beam). or a predetermined or signaled propagation delay (eg, associated with a sub-narrow beam boundary).

Although the description illustrates the use of propagation delay differences for preamble and root sequence selection, one skilled in the art will appreciate that any propagation delay-related information/parameter may be used for such selection.

Although the description illustrates the use of propagation delay differences to obtain RA-RNTI, one skilled in the art will appreciate that any propagation delay-related information/parameter may be used for such derivation.

Data processing systems and methods in accordance with exemplary embodiments may be executed by one or more processors executing sequences of instructions contained in a storage device. Such instructions may be read into the storage device from other computer-readable media, such as secondary storage device(s). Execution of the instruction sequences contained in the memory device causes the processor to operate, for example, as described above. In alternative embodiments, hardware circuitry may be used instead of or in combination with software instructions to implement the present invention. Such software may run remotely on a processor located within a robotic assistive system/device (RAA) and/or other mobile device. In the latter case, data may be transferred via a wired or wireless connection between the RAA or other mobile device containing the sensors and a remote device containing a processor that runs software that performs scale estimation and compensation as described above. According to other exemplary embodiments, a portion of the processing described above with respect to location determination may be performed in a device containing sensors/cameras, and the remainder of the processing may be performed in a second device after receiving partially processed data from the device containing sensors/cameras.

Although the features and elements are described above in specific combinations, one skilled in the art will appreciate that each feature or element can be used alone or in any combination with other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware embedded in a computer-readable medium for execution by a computer or processor. Examples of volatile computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), register, cache memory, semiconductor storage devices, magnetic media such as internal hard drives and removable drives, magneto-optical media and optical media such as CD-ROMs and digital versatile discs (DVDs). The processor, in combination with software, may be used to implement an RF transceiver for use in a WTRU, UE, terminal, base station, RNC, and/or any host computer.

Also noted in the embodiments described above are processing platforms, computing systems, controllers, and other devices comprising processors. These devices may include at least one central processing unit (CPU) and a storage device. As practiced by those skilled in computer programming, action instructions and symbolic representations of steps or commands can be implemented using a variety of CPUs and storage devices. Such actions and steps or commands may be referred to as “executable,” “computer-executable,” or “CPU-executable.”

It will be apparent to one skilled in the art that the above actions and symbolically represented steps or commands involve controlling electrical signals by the CPU. The electrical system provides data bits that can cause the resulting conversion or attenuation of the electrical signals and storage of the data bits in storage cells in the storage device system to thereby reconfigure or otherwise alter CPU operation as well as other signal processing. The storage cells in which data bits are stored are physical locations that have certain electrical, magnetic, optical, or organic properties corresponding to or characteristic of the data bits. It should be understood that exemplary embodiments are not limited to the aforementioned platforms or CPUs and that other platforms and CPUs may also support the proposed methods.

Data bits may also be stored on computer-readable media, including magnetic disks, optical disks, and any other volatile (such as random access memory (RAM)) or non-volatile (such as read-only memory (ROM)) mass storage device readable by the CPU . Computer-readable media may include interoperable or interconnected computer-readable media used solely within a processing system or distributed among a plurality of interconnected processing systems, which may be local or remote to said processing system. It is understood that exemplary embodiments are not limited to the aforementioned storage devices and that other platforms and storage devices may also support the described methods. It should be understood that exemplary embodiments are not limited to the aforementioned platforms or CPUs and that other platforms and CPUs may also support the proposed methods.

In an illustrative embodiment, any of the steps, methods, etc. described herein may be implemented as computer-readable instructions stored on a computer-readable medium. The mobile device processor, network element, and/or any other computing device may be configured to execute machine-readable instructions.

Minor differences remain between hardware and software implementations of aspects of the systems. The use of hardware or software usually (but not always, since in certain contexts the difference between hardware and software can become significant) involves choosing a design that represents a trade-off between cost and efficiency. There may be various means by which the methods and/or systems and/or other technologies described herein can be implemented (e.g., hardware, software and/or firmware), and the preferred means may vary depending on the context in which said methods and/or systems and/or other technologies are deployed. For example, if a developer determines that speed and accuracy are of paramount importance, he may use primarily hardware and/or firmware. If flexibility is most important, the developer may choose to implement primarily in software. In an alternative embodiment, the developer may use a combination of hardware, software and/or firmware.

The above detailed description sets forth various embodiments of devices and/or methods using block diagrams, block diagrams and/or examples. Since such block diagrams, block diagrams and/or examples contain one or more functions and/or operations, it will be apparent to those skilled in the art that each function and/or operation in such block diagrams, block diagrams or examples can be implemented separately and/or in conjunction with a wide variety of hardware, software, firmware, or essentially any combination thereof. By way of example, suitable processors include a general purpose processor, a special purpose processor, a standard processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, application specific integrated circuits (ASICs), standard parts application specific integrated circuit (ASSP); a field programmable gate array (FPGA), an integrated circuit (IC) of any other type, and/or a state machine.

Although the features and elements are presented above in specific combinations, one skilled in the art will appreciate that each feature or element can be used alone or in any combination with other features and elements. The present invention is not limited to the specific embodiments described herein, which are intended to illustrate various aspects. It will be apparent to those skilled in the art that many modifications and changes can be made without departing from the spirit and scope of the present invention. No elements, actions or instructions used in the specification of this application should be construed as critical or essential to the invention unless expressly stated otherwise. Functionally equivalent methods and devices included in the scope of the description, in addition to those listed herein, will become apparent to those skilled in the art upon reading the above descriptions. It is intended that such modifications and changes be included within the scope of the appended claims. The present description is limited solely by the appended claims and the full range of equivalents to which such claims apply. It should be understood that the present description is not limited to specific methods or systems.

In addition, it should be understood that the terms used herein are used only for the purpose of describing specific embodiments of the present invention and are not intended to be limiting. As used herein, the terms “station” and its abbreviation STA, “user equipment” and its abbreviation UE may refer to (i) a wireless transmit/receive unit (WTRU), for example, as described below; (ii) any of a number of embodiments of a WTRU, such as those described below; (iii) a wireless and/or wired (eg, plug-in) device, made, in particular, using some or all of the designs and functionality of the WTRU, for example, as described below; (iii) a wireless and/or wired device not configured with all WTRU designs and functionality, such as those described below; or (iv) etc. Below with reference, for example, to FIG. 1A through 1D provide detailed information regarding an example WTRU, which may be any UE described herein.

In certain exemplary embodiments, certain portions of the subject matter described herein may be implemented using application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), digital signal processors (DSPs), and/or other integrated circuit formats. However, those skilled in the art will appreciate that certain aspects of the embodiments described herein, in whole or in part, may be equivalently implemented on integrated circuits in the form of one or more computer programs executing on one or more computers (e.g., in the form of one or more programs running on one or more computer systems), in the form of one or more programs running on one or more processors (for example, in the form of one or more programs running on one or more microprocessors), in the form of firmware, or in the form of software essentially any combination thereof and that designing circuits and/or writing code for software and/or firmware would be within the capabilities of one skilled in the art after reading this disclosure. In addition, it will be apparent to those skilled in the art that the subject matter mechanisms described herein can be distributed as a software product in a variety of forms and that the exemplary embodiment of the subject matter described herein applies regardless of the particular type of environment. signaling used to actually effect such distribution. Examples of the signal medium include, but are not limited to, the following: a recordable medium such as a floppy disk, hard disk drive, CD, DVD, digital tape, computer storage device, etc., and a medium capable of transmission, such as digital and/or analog transmission media (eg, fiber optic cable, waveguide, wired line, wireless line, etc.).

The subject matter described herein sometimes illustrates various components contained within or connected to various other components. It should be understood that such illustrated architectures are examples only and that various other architectures with the same functionality may in fact be implemented. In a conceptual sense, any design of components to achieve the same functionality is practically "coupled" with the ability to provide the desired functionality. Therefore, any two components combined herein to achieve a particular functionality can be considered to be "tied" together to provide the desired functionality, regardless of architectures or intermediate components. Likewise, any two components connected in this way can be considered to be "operably connected" or "operably coupled" to each other to provide the desired functionality, and any two components that can be connected in this way can also be considered to be "operably connected" to each other to provide the desired functionality. » with each other to provide the desired functionality. Specific examples of interoperable components include, but are not limited to, components configured to be physically interoperable and/or physically and/or logically and/or wirelessly interoperable, and/or components interoperable logically and/or wirelessly.

With respect to the use of substantially any plural and/or singular variations for terms herein, those skilled in the art may change plural to singular and/or singular to plural as the context and/or scope of application requires. Various singular/plural combinations may be explicitly stated herein for clarity.

It will be apparent to those skilled in the art that, in general, terms used herein, and particularly in the appended claims (e.g., in the main portion of the appended claims), are generally considered to be "non-limiting" terms (e.g., the term "including " should be interpreted as "including without limitation", the term "having" should be interpreted as "having at least", the term "includes" should be interpreted as "including without limitation", etc.). Moreover, it will be apparent to those skilled in the art that if a specific number of claims are intended to be included, such intent will be expressly stated in the claims, and in the absence of such mention, there is no such intent. For example, if only one element is being referred to, the term "one" or a similar term may be used. To facilitate understanding, the following appended claims and/or descriptions herein may contain the introductory phrases “at least one” and “one or more” to introduce the enumeration of claims. However, the use of such phrases should not be construed as implying that the introduction of a claim enumeration with singular grammatical forms limits any particular claim containing such introduced claim enumeration to embodiments containing only one such enumeration, even if the same claim includes introductory phrases "one or more" or "at least one" and singular grammatical forms (for example, singular grammatical forms should be interpreted to mean "at least" or "one or more"). The same is true with respect to the use of certain grammatical forms used to introduce enumeration of claims. Moreover, even if a specific number of included enumerated claims is explicitly stated, it will be apparent to those skilled in the art that such enumeration should be interpreted to mean at least the stated number (e.g., simply stating "two claims" without other qualifications means at least two points or two or more points). In addition, when using a rule similar to the rule “at least one of A, B and C, etc.”, in general, one skilled in the art will understand the rule implied by such a construction (for example, “a system containing at least one of A, B, and C" will include, without limitation, systems that contain only A, only B, only C, both A and B, both A and C, both B and C, and/or both A, B and C, etc.). When using a rule similar to the rule “at least one of A, B or C, etc.”, the rule implied by such a construction will generally be clear to one skilled in the art (for example, “a system containing at least one of A, B or C" will include, without limitation, systems that contain only A, only B, only C, both A and B, both A and C, both B and C, and/or both A, B and C, etc.). In addition, it will be apparent to those skilled in the art that substantially any dividing word and/or dividing phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to imply the possibility of including one of the terms , either term, or both terms. For example, the phrase "A or B" should be understood to include the possibilities "A" or "B" or "A and B." In addition, as used herein, the term “any of” followed by a list of a plurality of elements and/or a plurality of categories of elements shall include “any of”, “any combination of”, “any plurality of” and/or “any a combination of a plurality of elements and/or categories of elements, alone or in combination with other elements and/or other categories of elements. Additionally, as used herein, the term “set” or “group” includes any number of elements, including zero. In addition, as used herein, the term “quantity” includes any quantity, including zero.

Moreover, if features or aspects of the present disclosure are described in terms of Markush groups, it will be apparent to those skilled in the art that the present disclosure is thus also described in terms of any individual member or subset of members of a Markush group.

As will be apparent to one skilled in the art, for all purposes such as providing a written description, all ranges described herein also include all possible subranges and combinations of subranges thereof. Any of the listed ranges can be readily recognized as providing sufficient description and as a range that can be broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. By way of non-limiting example, each range described herein can be easily broken down into a lower third, a middle third, and an upper third, etc. As will be apparent to one skilled in the art, all terms such as “up to,” “at least,” “more than,” “less than,” and the like. include a specified number and refer to ranges that can subsequently be broken down into subranges as described above. Finally, as will be apparent to one skilled in the art, the range includes each individual element. Thus, for example, a group containing 1-3 cells refers to groups containing 1, 2 or 3 cells. Similarly, a group containing 1–5 honeycombs refers to groups containing 1, 2, 3, 4 or 5 honeycombs, etc.

Moreover, the claims should not be construed as limited to the proposed order or elements unless otherwise indicated. In addition, use of the term "intended for" in any claim is intended to imply reference to 35 U.S.C. §112 ¶ 6 or the means-plus-function claim format, and any claim not containing the term " means” does not indicate a purpose for something.

The processor, in combination with software, may be used to implement an RF transceiver for use in a wireless transmit/receive unit (WTRU), user equipment (UE), terminal, base station, mobility management entity (MME), or enhanced packet core (EPC), or any host computer. The WTRU may be used in combination with modules implemented in hardware and/or software, including a software-defined radio (SDR) system and other components such as a camera, video camera module, video phone, speakerphone, vibrator, speaker, microphone , TV transceiver, headphones with microphone, keyboard, Bluetooth® module, frequency modulation (FM) radio module, near field communication (NFC) module, liquid crystal display (LCD) unit, organic light-emitting diode (OLED) display unit, digital music player, multimedia player, video game player module, Internet browser and/or any wireless local area network (WLAN) or ultra-wideband (UWB) module.

It will be apparent to those skilled in the art that, as used herein, certain exemplary embodiments may be used in an alternative embodiment or in combination with other exemplary embodiments.

Claims (59)

1. A method for selecting a random access channel (RACH) preamble in non-terrestrial networks (NTN) implemented by a wireless transmit/receive unit (WTRU), the method including: receiving by the WTRU from a network access point (NAP) configuration information indicating a plurality of preambles and corresponding thresholds related to propagation delay; determining information related to propagation delay associated with the distance between the WTRU and the NAP or location within the coverage area of the NAP; selecting a subset of preambles from the plurality of preambles based on certain information related to the propagation delay; randomly selecting a preamble from a selected subset of preambles; And sending a randomly selected preamble to the NAP. 2. The method of claim 1, further comprising selecting a root sequence, wherein selecting a subset of preambles includes selecting a subset of preambles in accordance with the selected root sequence. 3. The method according to claim 1, additionally including the WTRU receives network access information from the NAP; initiating network access by the WTRU using the network access information; determining, by the WTRU, a random access radio network temporary identifier (RA-RNTI), which is a function of, derived from, or includes at least certain information related to propagation delay; And decoding by the WTRU the network access information included in the random access response (RAR) using the determined RA-RNTI. 4. The method of claim 1, wherein the NAP is included in the satellite and is part of a non-terrestrial network, the method further comprising the WTRU receiving from the NAP via system information any of the following: (1) GNSS coordinates periodically or (2) the NAP's usable elevation angle; And WTRU altitude determination, wherein the determination of information related to propagation delay is further based on the determined height and received system information. 5. Method according to any one of paragraphs. 1-4, wherein the propagation delay-related information includes any of the following: (1) the distance from the WTRU to the NAP; (2) distance from WTRU to NAP nadir; (3) the angle between the line between the WTRU and the NAP and the line between the nadir of the NAP and the NAP; or (4) propagation delay or differential propagation delay of the signal sent between the WTRU and the NAP. 6. Method according to any one of paragraphs. 1-4, further comprising receiving by the WTRU, through broadcast information or dedicated signaling, random access configuration information indicating a plurality of thresholds related to propagation delay, and any of the following: (1) location information indicating the location of the NAP; or (2) trajectory information indicating the trajectory that the NAP should traverse. 7. Method according to any one of paragraphs. 1-4, in which selecting a subset of preambles from the plurality of preambles includes selecting one orthogonal subset of the plurality of preambles that corresponds to a particular portion of the NAP coverage area; each part of the NAP coverage area corresponds to a different subset of the plurality of preambles; And each orthogonal subset of the plurality of preambles is any of the following: (1) preconfigured with appropriate thresholds related to propagation delay; or (2) explicitly communicated through NAP signaling. 8. Method according to any one of paragraphs. 1-4, wherein selecting a subset of preambles from the plurality of preambles includes defining a sub-area of NAP coverage; And selecting a subset of preambles associated with a sub-area of NAP coverage by any of the following: (1) comparing a determined value of propagation delay-related information with one or more propagation delay-related thresholds; or (2) by means of a reference table associated with a certain value of information related to the propagation delay. 9. Method according to any one of paragraphs. 1-4, further comprising receiving the constraint information by the WTRU from the NAP and limiting in accordance with the constraint information any of the following: (1) one or more random access channel (RACH) elements to send a randomly selected preamble to the NAP; or (2) the number of cyclic shifts associated with the RACH root sequence applied by the WTRU. 10. Method according to any one of paragraphs. 1-4, in which sending a randomly selected preamble is limited to the first random access channel (RACH) element or the first set of RACH elements, provided that the WTRU is in any of the following: (1) the first NAP coverage area; (2) the first range of distances to the NAP nadir; (3) a first range of distances to the NAP or (4) a first range of propagation delays to the NAP; And sending a randomly selected preamble is limited to a second RACH element or a second set of RACH elements, provided that the WTRU is in any of the following: (1) a second NAP coverage area; (2) a second range of distances to the NAP nadir; (3) a second range of distances to the NAP or (4) a second range of propagation delays to the NAP. 11. Wireless transmission/reception unit (WTRU), including a transmission/reception module configured to receive from a network access point (NAP) configuration information indicating a plurality of preambles and corresponding thresholds related to propagation delay; And processor configured to determining information related to propagation delay associated with the distance between the WTRU and the NAP or location within the NAP coverage area, selecting a subset of preambles from the plurality of preambles based on certain information related to propagation delay, and random selection of a preamble from a selected subset of preambles, wherein the transmission/reception module is configured to send a randomly selected NAP preamble. 12. The WTRU of claim 11, wherein the processor is configured to select a root sequence and select a subset of preambles in accordance with the selected root sequence. 13. WTRU according to claim 11, in which the transmission/reception module is configured to receive network access information from the NAP; And the processor is configured to initiating network access using network access information; determining a random access radio network temporary identifier (RA-RNTI), which is a function of, derived from, or includes at least information related to propagation delay; And decoding the network access information included in the random access response (RAR) using the determined RA-RNTI. 14. The WTRU of claim 11, wherein the propagation delay-related information includes any of the following: (1) the distance from the WTRU to the NAP; (2) distance from WTRU to NAP nadir; (3) the angle between the line between the WTRU and the NAP and the line between the nadir of the NAP and the NAP; or (4) propagation delay or differential propagation delay of the signal sent between the WTRU and the NAP. 15. WTRU according to any one of paragraphs. 11-14, wherein the transmitting/receiving module is configured to receive, through broadcast information or dedicated signaling, a random access configuration including a plurality of thresholds related to propagation delay, and any of the following: (1) location information indicating NAP location; or (2) trajectory information indicating the trajectory that the NAP should traverse. 16. WTRU according to any one of paragraphs. 11-14, in which the processor is configured to select one orthogonal subset of the plurality of preambles that corresponds to a particular portion of the NAP coverage area; each part of the NAP coverage area corresponds to a different subset of the plurality of preambles; And each orthogonal subset of the plurality of preambles is any of the following: (1) preconfigured with appropriate thresholds related to propagation delay; or (2) explicitly communicated through NAP signaling. 17. WTRU according to any one of paragraphs. 11-14, in which the processor is configured to defining a sub-area of NAP coverage; And selecting a subset of preambles associated with a coverage sub-area by any of the following: (1) comparing a determined value of propagation delay-related information with one or more propagation delay-related thresholds; or (2) by means of a reference table associated with a certain value of information related to the propagation delay. 18. WTRU according to any one of paragraphs. 11-14, in which the processor is configured to determine information related to propagation delay in accordance with location information indicating the location of the NAP; or (2) path information indicating the path that the NAP must traverse. 19. WTRU according to any one of paragraphs. 11-14, additionally including a transmission/reception module that is configured to receive restriction information from the NAP; And a processor that is configured to constrain, in accordance with the constraint information, any of the following: (1) one or more RACH elements for sending a randomly selected preamble to the NAP; or (2) the number of cyclic shifts associated with the RACH root sequence applied by the WTRU. 20. WTRU according to any one of paragraphs. 11-14, in which the processor is configured to limiting a randomly selected preamble to the first RACH element or the first set of RACH elements, provided that the WTRU is in any of the following: (1) the first NAP coverage area; (2) the first range of distances to the NAP nadir; (3) a first range of distances to the NAP or (4) a first range of propagation delays to the NAP; And limiting a randomly selected preamble to a second RACH element or a second set of RACH elements, provided that the WTRU is in any of the following: (1) a second NAP coverage area; (2) a second range of distances to the NAP nadir; (3) a second range of distances to the NAP or (4) a second range of propagation delays to the NAP.