Rach procedure for user equipment of non-terrestrial networks

Abstract

This invention discloses methods and systems for enhancing the NR RACH process to adapt to non-terrestrial networks (NTN). The length of the RAR window can be extended. The NTN-RNTI associated with the time-frequency resources used for the PRACH preamble can be used to scramble the CRC of the DCI used to schedule RAR messages within the RAR window. The DCI content may include information about the associated PRACH preamble to help the UE distinguish RAR messages triggered by PRACH preambles transmitted by different UEs from different frames. In one aspect, the NTN-RNTI can encode information about the system frame when the UE transmits the PRACH preamble. In another aspect, the RA-RNTI associated with the time-frequency resources used for the PRACH preamble transmitted from different frames can be used to scramble different subsets of the CRC of the DCI to help the UE decode the RAR message intended for the UE.

Description

Technical Field

[0001] This disclosure relates to the field of wireless communications, and more specifically to methods and systems that enable wireless communication devices to perform random access channel (RACH) procedures on non-terrestrial networks. Other aspects are also described. Background Technology

[0002] As the number of mobile devices connected to wireless networks continues to increase and the demand for mobile data traffic continues to grow, system requirements and architectures are being modified to meet current and anticipated rapid growth. For example, wireless communication networks such as 5G New Radio (NR) systems may need to be deployed using satellites as part of a non-terrestrial network (NTN). In one NTN deployment scenario, satellites, referred to as transparent satellites, can act as relay stations to link user equipment (UEs) with terrestrial base stations and the 5G core network by implementing a transparent payload. In another deployment scenario, satellites, referred to as regenerative satellites, can have onboard processing capabilities to perform base station functions by implementing a regenerative payload between UEs and the terrestrial 5G core network. Due to the wide coverage area of ​​satellites and the greater distance between satellites and terrestrial UEs, the propagation delay difference between two UEs within the beam area is greater than that encountered in strictly terrestrial networks. For example, for an NTN deploying satellites in geostationary orbit (GEO), the maximum differential delay between points at the lowest and edge of the coverage area can be 10.3 ms. For NTN satellites deployed in low Earth orbit (LEO), the maximum differential delays at altitudes of 600 km and 1200 km can be 3.12 ms and 3.18 ms, respectively.

[0003] When a User Equipment (UE) performs a contention-based RACH procedure to gain initial access to the NTN, large propagation delays for UEs and significant differences in propagation delays between UEs within the beam occupancy area can cause problems. A UE can initiate a RACH procedure by sending a Physical Random Access Channel (PRACH) transmission to the base station. The UE can transmit the PRACH as a preamble during a system frame using time-frequency resources uniquely associated with its Random Access Radio Network Temporary Identifier (RA-RNTI). The base station can derive the UE's RA-RNTI from the time-frequency resources carrying the PRACH and can send a Random Access Response (RAR), whose scheduling downlink control information (DCI) cyclic redundancy check (CRC) is scrambled by the RA-RNTI to identify the RAR as intended for use by the UE. The UE can search for the RAR in the common search space by attempting to decode it using its RA-RNTI. When the UE successfully decodes the RAR, it can use the uplink resources granted by the RAR to attempt to gain access to the network.

[0004] The common search space, known as the RAR window (during which user equipment searches for RARs), lasts only one frame. This duration may be too short to accommodate the maximum differential delay of user equipment performing the RACH procedure in an NTN. If the RAR window is extended, it may become more ambiguous for user equipment to determine whether a RAR is intended for that RAR window, as the RAR window can contain multiple RARs generated in response to multiple user equipments with the same RA-RNTI transmitting PRACH using the same time-frequency resources across different system frames spanning the maximum differential delay. That is, multiple RARs within a RAR window can have their CRCs scrambled with the same RA-RNTI, making it difficult for a user equipment to determine whether it is the intended recipient of the RAR. Other complications may arise for the RACH procedure in an NTN, including determining whether and how the start of the RAR window is delayed due to a long maximum propagation delay. Summary of the Invention

[0005] This invention discloses methods and systems for enhancing NR RACH procedures to adapt to non-terrestrial networks (NTN). RACH procedures from user equipment (UE) or from base stations (referred to as "gNodeB" or "gNB" in 5G NR) can be modified. The start and length of the RAR window can be extended based on the range of propagation delays (e.g., LEO or GEO satellites). When the length of the RAR window is extended, the NTN-RNTI associated with the time-frequency resources used for the PRACH preamble can be used to scramble the CRC of Downlink Control Information (DCI) format 1_0 used for downlink allocation in the RAR. The DCI format 1_0 content may include information about the associated PRACH preamble to help the UE distinguish RARs generated as responses to PRACH preambles transmitted by different UEs from different system frames based on the same RA-RNTI. In one aspect, when the UE transmits the PRACH preamble, the NTN-RNTI may contain information about the system frame. In one respect, the RA-RNTI associated with the time-frequency resources of the PRACH preamble used for transmission from different frames can be used for different subsets of the CRC of scrambling DCI format 1_0 to help the UE distinguish the RAR generated in response to different PRACH preambles.

[0006] In one aspect, the UE can perform blind retransmission of the PRACH preamble to indicate the expansion of the RAR window. In another aspect, the UE can change the RAR window offset, which determines the start of the RAR window based on the end of the PRACH preamble transmission, based on the known location information and therefore the UE's propagation delay.

[0007] In one aspect, the gNB can perform blind retransmissions of the RAR within the RAR window to improve the transmission reliability of the NTN. The number of blind retransmissions and the transmission mode can depend on PRACH reception conditions, uplink channel conditions, or can be pre-configured. In another aspect, due to the long propagation delay associated with the NTN, the gNB can extend the K1 and K2 values ​​that determine the delay between uplink and downlink transmissions to align with Time Domain Duplex (TDD) uplink-downlink configurations. In yet another aspect, the gNB can broadcast or multicast the RAR window size extension value to the UE based on the satellite's orbital altitude.

[0008] The above overview does not include an exhaustive list of all aspects of this disclosure. It is contemplated that the aspects of this disclosure include all systems and methods that can be implemented by all suitable combinations of the aspects outlined above and the various aspects disclosed in the detailed embodiments below and specifically pointed out in the claims filed with this patent application. Such combinations have specific advantages not specifically described in the above overview. Attached Figure Description

[0009] The aspects of this disclosure are illustrated by way of example and are not limited to the illustrations in the accompanying drawings, in which similar reference numerals indicate similar elements. It should be noted that references to “a” or “an” aspect in this disclosure do not necessarily refer to the same aspect, and each refers to at least one. Furthermore, for the sake of brevity and to reduce the total number of drawings, a given drawing may be used to illustrate more than one aspect of this disclosure, and for a given aspect, not all elements in that drawing may be necessary.

[0010] Figure 1 An exemplary wireless communication system according to some aspects of this disclosure is shown.

[0011] Figure 2 A base station (BS) communicating with a user equipment (UE) device according to some aspects of this disclosure is shown.

[0012] Figure 3 An exemplary block diagram of a UE according to some aspects of this disclosure is shown.

[0013] Figure 4 An exemplary block diagram of a BS according to some aspects of this disclosure is shown.

[0014] Figure 5 An exemplary block diagram of a cellular communication circuit according to some aspects of this disclosure is shown.

[0015] Figure 6 The RAR window size expansion based on the DCI field is shown according to some aspects of this disclosure.

[0016] Figure 7 An RNTI-based RAR window size expansion is shown according to some aspects of this disclosure.

[0017] Figure 8 PRACH blind retransmissions performed by the UE over multiple frame numbers according to some aspects of this disclosure are shown to indicate the expansion of the RAR window size.

[0018] Figure 9 Different locations of DCI are shown using RA-RNTI according to some aspects of this disclosure.

[0019] Figure 10 The timing relationship in the NTN between the base station and the UE is shown, which uses the time advance adjustment of the UE based on the round-trip propagation delay between the base station and the UE.

[0020] Figure 11 This is a data flow diagram illustrating an example of a method for a UE to transmit a PRACH preamble to a base station and receive RAR messages from the base station on an extended RAR window to perform a RACH procedure, according to some aspects of this disclosure.

[0021] Figure 12 This is a flowchart illustrating an example of a method for a base station to receive a PRACH preamble from a UE, determine the RNTI, and transmit RAR to the UE on an extended RAR window based on the RNTI, according to some aspects of this disclosure. Detailed Implementation

[0022] This invention discloses techniques for enhancing the NR RACH process to adapt to non-terrestrial networks (NTNs) or other networks with long propagation delays. The start and length of the RAR window used for the RACH process can be extended based on the range of propagation delays (e.g., LEO or GEO satellites). The RNTI associated with the time-frequency resources used for the PRACH preamble and the number of frames transmitted by the UE for PRACH can be used to scramble the CRC of DCI format 1_0 in the RAR to help the UE distinguish between a RAR intended for use by the UE and a RAR generated as a response to PRACH preambles transmitted by other UEs during different system frames.

[0023] In one aspect, a method for a UE to access an NTN is disclosed. The method includes the UE transmitting a PRACH preamble to a base station of the NTN (such as a gNB in ​​5G NR) during a frame to request access to the NTN. The frame may be part of a frame structure comprising multiple frames. The method also includes the UE receiving a RAR message from the base station during a RAR window. The RAR window may span multiple frames of the frame structure. The method further includes the UE determining whether a RAR message received from the base station is intended for use by the UE based on an indication in the downlink control information (DCI) that schedules the RAR message.

[0024] In one aspect, a method is disclosed for a gNB (gN) of a base station, such as in 5G NR, to grant access to an NTN based on a request from a UE. The method includes the base station receiving a PRACH preamble from the UE during a frame to request access to the NTN. The method also includes the base station determining an RNTI (Real-Time Interchange Title) based on time-frequency resources used for the frame carrying the PRACH preamble. The method further includes the base station transmitting a RAR (Real-Time Interchange) message during a RAR window spanning multiple frames. The RAR message is scheduled by a DCI (Distributed Control Center) that includes an indication that allows the UE to determine, based on the RNTI and the number of frames used for the frame carrying the PRACH preamble, that the RAR message is intended for use by the UE.

[0025] The following description illustrates many specific details. However, it should be understood that aspects of this disclosure can be practiced without requiring these specific details. In other instances, well-known circuits, structures, and techniques have not been shown in detail so as not to obscure the understanding of this description.

[0026] The terminology used herein is for the purpose of describing particular aspects only and is not intended to limit the scope of this disclosure. Spatially related terms, such as “below,” “under,” “down,” “above,” “above,” etc., may be used herein for the convenience of describing the relationship of one element or feature to one or more other elements or features, as illustrated in the accompanying drawings. It should be understood that spatially related terms are intended to cover different orientations of the device during use or operation other than those shown in the drawings. For example, if the device in the figures is flipped, an element described as “below” or “under” other elements or features may then be oriented “above” other elements or features. Thus, the exemplary term “below” can cover both orientations above and below. The device may be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatially related descriptors used herein are interpreted accordingly.

[0027] As used herein, the singular forms “a” and “an” are intended to include the plural forms as well, unless the context otherwise indicates. It should be further understood that the terms “comprising” and “including” define the presence of the stated feature, step, operation, element, or component, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, or groups thereof.

[0028] The terms “or” and “and / or” as used herein should be interpreted as including or referring to any one or any combination thereof. Therefore, “A, B, or C” or “A, B, and / or C” means “any one of the following: A; B; C; A and B; A and C; B and C; A, B, and C.” Exceptions to this definition will only occur if the combination of elements, functions, steps, or actions is inherently mutually exclusive in some way.

[0029] Figure 1 A simplified exemplary wireless communication system is shown, based on several aspects. It should be noted that... Figure 1 The system described herein is merely one example of a possible system, and the features of this disclosure can be implemented in any of a variety of systems as needed.

[0030] As shown in the figure, the exemplary wireless communication system includes a base station 102A, which communicates with one or more user equipments 106A, 106B, etc., through a transmission medium. Each of the user equipments may be referred to herein as a "user equipment" (UE). Therefore, user equipment 106 is referred to as a UE or UE device.

[0031] Base station (BS) 102A may be a transceiver base station (BTS) or a cell site (“cellular base station”), and may include hardware enabling wireless communication with UEs 106A to 106N. In one aspect, base station 102A may be deployed as a satellite, referred to as a regenerable satellite, carrying onboard processing capabilities to perform the functions of a base station to implement a regenerable payload between the UE and the terrestrial core network.

[0032] The communication area (or coverage area) of a base station can be referred to as a "cell". Base station 102A and UE 106 can be configured to communicate via a transmission medium using any of a variety of Radio Access Technologies (RATs), also known as wireless communication technologies or telecommunications standards, such as GSM, UMTS (associated with air interfaces such as WCDMA or TD-SCDMA), LTE, LTE-Advanced (LTE-A), 5G New Radio (5G NR), HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), etc. Note that if base station 102A is implemented in an LTE environment, its alternative location can be referred to as an "eNodeB" or "eNB". Note that if base station 102A is implemented in a 5G NR environment, its alternative location can be referred to as a "gNodeB" or "gNB".

[0033] As shown in the figure, base station 102A can also be configured to communicate with network 100 (e.g., in various possibilities, the core network of a cellular service provider, telecommunications networks such as the Public Switched Telephone Network (PSTN), and / or the Internet). Therefore, base station 102A can facilitate communication between user equipments and / or between user equipments and network 100. Specifically, cellular base station 102A can provide UE 106 with various telecommunications capabilities such as voice, short message service (SMS), and / or data services.

[0034] Base station 102A and other similar base stations (such as base station 102B...102N) operating under the same or different cellular communication standards can thus provide a network as a cell, which can provide continuous or near-continuous overlapping services to UE 106A-N and similar devices over a geographical area via one or more cellular communication standards.

[0035] Therefore, although base station 102A can act as such Figure 1 The diagram shows the "serving cell" of UEs 106A-N, but each UE 106 may also be able to receive signals (and possibly within its communication range) from one or more other cells (which may be provided by base stations 102B-N and / or any other base stations), which may be referred to as "neighboring cells". Such cells may also facilitate communication between user equipments and / or between user equipments and network 100. These cells may include "macro" cells, "micro" cells, "pecimen" cells, and / or any other cells of various other granularities providing service area size. For example, in Figure 1Base stations 102A-B shown can be macro cells, while base station 102N can be micro cells. Other configurations are also possible. UE 106 can measure the time of arrival (TOA) of Position Reference Signals (PRS) transmitted by its serving base station 102A and by base stations 102B-N of neighboring cells to support the location determination of UE 106.

[0036] In some aspects, base station 102A can be a next-generation base station, such as a 5G New Radio (5G NR) base station or a "gNB". In some aspects, the gNB can connect to a legacy evolved packet core (EPC) network and / or to an NR core (NRC) network. Furthermore, a gNB cell can include one or more transition and receive points (TRPs). Additionally, a UE capable of operating according to 5G NR can connect to one or more TRPs within one or more gNBs.

[0037] It should be noted that UE 106 can communicate using multiple wireless communication standards. For example, in addition to at least one cellular communication protocol (e.g., GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE-A, 5G NR, HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD, etc.), UE 106 can be configured to communicate using wireless networking (e.g., Wi-Fi) and / or peer-to-peer wireless communication protocols (GSM, for example, Bluetooth, Wi-Fi peer-to-peer, etc.). If desired, UE 106 can also or alternatively be configured to communicate using one or more Global Navigation Satellite Systems (GNSS, such as GPS or GLONASS), one or more mobile television broadcasting standards (e.g., ATSC-M / H or DVB-H), and / or any other wireless communication protocol. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

[0038] Figure 2 User equipment 106 (e.g., one of devices 106A to 106N) communicating with base station 102 is shown according to some aspects. UE 106 can be a device with cellular communication capabilities, such as a mobile phone, handheld device, computer, or tablet computer, or virtually any type of wireless device.

[0039] UE 106 may include a processor configured to execute program instructions stored in memory. UE 106 may perform any of the methods described herein by executing such stored instructions. Alternatively or additionally, UE 106 may include programmable hardware elements, such as FPGAs (Field Programmable Gate Arrays), configured to perform any of the methods described herein or any portion thereof.

[0040] UE 106 may include one or more antennas for communicating using one or more wireless communication protocols or technologies. In some embodiments, UE 106 may be configured to communicate using, for example, CDMA2000 (1xRTT / 1xEV-DO / HRPD / eHRPD) or LTE or 5G NR using a single shared radio component and / or GSM or LTE or 5G NR using a single shared radio component. The shared radio may be coupled to a single antenna or to multiple antennas (e.g., for MIMO) for performing wireless communication. Typically, the radio component may include any combination of baseband processor, analog radio frequency (RF) signal processing circuitry (e.g., including filters, mixers, oscillators, amplifiers, etc.) or digital processing circuitry (e.g., for digital modulation and other digital processing). Similarly, the radio component may use the aforementioned hardware to implement one or more receive chains and transmit chains. For example, UE 106 may share one or more portions of the receive chain and / or transmit chain among various wireless communication technologies such as those discussed above.

[0041] In some implementations, UE 106 may include separate transmit and / or receive chains (e.g., including separate antennas and other radio components) for each wireless communication protocol configured for communication. As another possibility, UE 106 may include one or more radio components shared among multiple wireless communication protocols, as well as one or more radio components uniquely used by a single wireless communication protocol. For example, UE 106 may include shared radio components for communication using either LTE or 5G NR (or LTE or 1xRTT, or LTE or GSM), and separate radio components for communication using each of Wi-Fi and Bluetooth. Other configurations are also possible.

[0042] Figure 3 An exemplary simplified block diagram of a communication device 106 according to some aspects is shown. It should be noted that... Figure 3The block diagram of the communication device is merely one example of possible communication devices. According to the implementation, among other devices, the communication device 106 may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop, notebook, or portable computing device), a tablet computer, and / or a combination of devices. As shown, the communication device 106 may include a set of components 300 configured to perform core functions. For example, this set of components may be implemented as a system-on-a-chip (SOC), which may include portions for various purposes. Alternatively, the set of components 300 may be implemented as individual components or groups of components for various purposes. This set of components 300 may be (e.g., communicatively; directly or indirectly) coupled to various other circuitry of the communication device 106.

[0043] For example, communication device 106 may include various types of memory (e.g., including NAND flash memory 310), input / output interfaces such as connector I / F 320 (e.g., for connection to a computer system; docking station; charging station; input devices such as microphone, camera, keyboard; output devices such as speaker; etc.), a display 360 that may be integrated with or external to communication device 106, and cellular communication circuitry 330 such as for 5G-NR, LTE, GSM, etc., and short- to medium-range wireless communication circuitry 329 (e.g., Bluetooth). TM (and WLAN circuitry). In some aspects, the communication device 106 may include wired communication circuitry (not shown), such as, for example, a network interface card for Ethernet.

[0044] Cellular communication circuitry 330 may be coupled (e.g., communicatively grounded; directly or indirectly) to one or more antennas, such as antennas 335 and 336 shown. Short-to-medium-range wireless communication circuitry 329 may also be coupled (e.g., communicatively grounded; directly or indirectly) to one or more antennas, such as antennas 337 and 338 shown. Alternatively, short-to-medium-range wireless communication circuitry 329 may be coupled (e.g., communicatively grounded; directly or indirectly) to antennas 337 and 338, or as an alternative, to antennas 335 and 336. Short-to-medium-range wireless communication circuitry 329 and / or cellular communication circuitry 330 may include multiple receive chains and / or multiple transmit chains for receiving and / or transmitting multiple spatial streams, such as in a multiple-input multiple-output (MIMO) configuration.

[0045] In some embodiments, as further described below, the cellular communication circuit system 330 may include dedicated receive chains for multiple RATs (e.g., a first receive chain for LTE and a second receive chain for 5G NR), which include and / or (e.g., communicatively, directly or indirectly) coupled to a dedicated processor and / or radio components. Furthermore, in some aspects, the cellular communication circuit 330 may include a single transmit chain that can be switched between radio components dedicated to a particular RAT. For example, a first radio component may be dedicated to a first RAT, such as LTE, and can communicate with a dedicated receive chain and a transmit chain shared with additional radio components, such as a second radio component that may be dedicated to a second RAT (e.g., 5G NR) and can communicate with a dedicated receive chain and a shared transmit chain.

[0046] The communication device 106 may also include one or more user interface elements and / or be configured to be used with one or more user interface elements. User interface elements may include a variety of components, such as a display 360 (which may be a touchscreen display), a keyboard (which may be a separate keyboard or may be implemented as part of the touchscreen display), a mouse, a microphone and / or a speaker, one or more cameras, one or more buttons, and / or any of a variety of other components capable of providing information to the user and / or receiving or interpreting user input.

[0047] The communication device 106 may also include one or more smart cards 345 with SIM (Subscriber Identity Module) functionality, such as one or more UICC cards (one or more general purpose integrated circuit cards) 345.

[0048] As shown in the figure, the SOC 300 may include a processor 302 and a display circuit 304. The processor executes program instructions for the communication device 106, and the display circuit performs graphics processing and provides display signals to the display 360. The processor 302 may also be coupled to a memory management unit (MMU) 340 (which may be configured to receive addresses from the processor 302 and translate those addresses into locations in memory (e.g., memory 306, read-only memory (ROM) 350, NAND flash memory 310)) and / or coupled to other circuitry or devices (such as the display circuit 304, short-range wireless communication circuitry 229, cellular communication circuitry 330, connector I / F 320, and / or display 360). The MMU 340 may be configured to perform memory protection and page table translation or setup. In some aspects, the MMU 340 may be included as part of the processor 302.

[0049] As described above, the communication device 106 can be configured to communicate using wireless and / or wired communication circuitry. The communication device 106 can be configured to transmit a request to attach to a first network node operating under a first RAT, and to transmit an indication that the wireless device is capable of maintaining substantially concurrent connections with the first network node and a second network node operating under a second RAT. The wireless device can also be configured to transmit a request to attach to a second network node. This request may include an indication that the wireless device is capable of maintaining substantially concurrent connections with both the first and second network nodes. Furthermore, the wireless device can be configured to receive an indication that dual connections with the first and second network nodes have been established.

[0050] As described herein, communication device 106 may include hardware and software components for implementing the aforementioned features of UL data for time-division multiplexing NSA (non-standalone) NR operation. For example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable storage medium), processor 302 of communication device 106 may be configured to implement some or all of the features described herein. Alternatively (or otherwise), processor 302 may be configured as a programmable hardware element such as an FPGA (Field-Programmable Gate Array) or configured as an ASIC (Application-Specific Integrated Circuit). Alternatively (or otherwise), in conjunction with one or more of other components 300, 304, 306, 310, 320, 329, 330, 340, 345, 350, 360, processor 302 of communication device 106 may be configured to implement some or all of the features described herein.

[0051] Furthermore, as described in this invention, processor 302 may include one or more processing elements. Therefore, processor 302 may include one or more integrated circuits (ICs) configured to perform the functions of processor 302. Additionally, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of one or more processors 302.

[0052] Furthermore, as described herein, both the cellular communication circuit 330 and the short-range wireless communication circuit 329 may include one or more processing elements. In other words, one or more processing elements may be included in the cellular communication circuit 330, and similarly, one or more processing elements may be included in the short-range wireless communication circuit 329. Therefore, the cellular communication circuit 330 may include one or more integrated circuits (ICs) configured to perform the functions of the cellular communication circuit 330. Furthermore, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of the cellular communication circuit 330. Similarly, the short-range wireless communication circuit 329 may include one or more ICs configured to perform the functions of the short-range wireless communication circuit 329. Furthermore, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of the short-range wireless communication circuit 329.

[0053] Figure 4 An exemplary block diagram of a base station 102 according to some aspects is shown. It should be noted that... Figure 4 The base station shown is merely one example of a possible base station. As illustrated, base station 102 may include a processor 404 capable of executing program instructions specific to base station 102. Processor 404 may also be coupled to a memory management unit (MMU) 440 or other circuitry or device, which may be configured to receive addresses from processor 404 and translate those addresses into locations in memory (e.g., memory 460 and read-only memory (ROM) 450).

[0054] Base station 102 may include at least one network port 470. Network port 470 may be configured to be coupled to a telephone network and provide access rights as described above. Figure 1 and Figure 2 The telephone network described herein includes multiple devices such as UE device 106.

[0055] Network port 470 (or an additional network port) may also be configured, or alternatively configured, to be coupled to a cellular network, such as the core network of a cellular service provider. The core network may provide mobility-related services and / or other services to multiple devices, such as UE device 106. In some cases, network port 470 may be coupled to a telephone network via the core network, and / or the core network may provide a telephone network (e.g., in addition to other UE devices served by the cellular service provider).

[0056] In some respects, base station 102 may be a next-generation base station, such as a 5G New Radio (5GNR) base station or a “gNB”. In such respects, base station 102 may connect to a legacy evolved packet core (EPC) network and / or to an NR core (NRC) network. Furthermore, base station 102 may be considered a 5G NR cell and may include one or more transition and receive points (TRPs). Additionally, UEs capable of operating according to 5G NR may connect to one or more TRPs within one or more gNBs.

[0057] Base station 102 may include at least one antenna 434 and possibly multiple antennas. The at least one antenna 434 may be configured to function as a wireless transceiver and may be further configured to communicate with UE device 106 via radio component 430. Antenna 434 communicates with radio component 430 via communication link 432. Communication link 432 may be a receive link, a transmit link, or both. Radio component 430 may be configured to communicate via various wireless communication standards, including but not limited to 5G-NR, LTE, LTE-A, GSM, UMTS, CDMA2000, Wi-Fi, etc.

[0058] Base station 102 may be configured to perform wireless communication using multiple wireless communication standards. In some cases, base station 102 may include multiple radio components that enable base station 102 to communicate according to multiple wireless communication technologies. For example, as one possibility, base station 102 may include an LTE radio component for performing communication according to LTE and a 5G NR radio component for performing communication according to 5G NR. In this case, base station 102 may be able to operate as both an LTE base station and a 5G NR base station. As another possibility, base station 102 may include a multimode radio component capable of performing communication according to any of multiple wireless communication technologies (e.g., 5G-NR and Wi-Fi, LTE and Wi-Fi, LTE and UMTS, LTE and CDMA2000, UMTS and GSM, etc.). As further described herein, BS 102 may include hardware and software components for implementing or supporting embodiments of the features described herein. The processor 404 of base station 102 may be configured to implement or support some or all of the methods described herein, for example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively, processor 404 may be configured as a programmable hardware element such as an FPGA (Field-Programmable Gate Array), or as an ASIC (Application-Specific Integrated Circuit), or a combination thereof. Alternatively (or in addition), in conjunction with one or more of other components 430, 432, 434, 440, 450, 460, and 470, processor 404 of BS 102 may be configured to implement or support some or all of the features described herein.

[0059] Furthermore, as described herein, processor 404 may comprise one or more processing elements. In other words, one or more processing elements may be included in processor 404. Therefore, processor 404 may include one or more integrated circuits (ICs) configured to perform the functions of processor 404. Additionally, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of processor 404.

[0060] Additionally, as described herein, the radio component 430 may comprise one or more processing elements. In other words, one or more processing elements may be included in the radio component 430. Therefore, the radio component 430 may include one or more integrated circuits (ICs) configured to perform the functions of the radio component 430. Furthermore, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of the radio component 430.

[0061] Figure 5An exemplary simplified block diagram of a cellular communication circuit according to some aspects is shown. It should be noted that... Figure 5 The block diagram of the cellular communication circuit is merely one example of a possible cellular communication circuit. Depending on the aspects, the cellular communication circuit 330 may be included in a communication device such as the communication device 106 described above. As mentioned above, the communication device 106 may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop, notebook, or portable computing device), a tablet computer and / or device, and other devices.

[0062] Cellular communication circuit 330 may (e.g., communicatively; directly or indirectly) be coupled to one or more antennas, such as ( Figure 3 Antennas 335a-b and 336 are shown in the diagram. In some embodiments, the cellular communication circuit 330 may include dedicated receive chains for multiple RATs (including and / or (e.g., communicatively grounded; directly or indirectly) coupled to a dedicated processor and / or radio components) (e.g., a first receive chain for LTE and a second receive chain for 5G NR). For example, as... Figure 5 As shown, the cellular communication circuit 330 may include a modem 510 and a modem 520. The modem 510 may be configured for communication according to a first RAT, such as LTE or LTE-A, and the modem 520 may be configured for communication according to a second RAT, such as 5G NR.

[0063] As shown, modem 510 may include one or more processors 512 and memory 516 communicating with processors 512. Modem 510 may communicate with radio frequency (RF) front end 530. RF front end 530 may include circuitry for transmitting and receiving radio signals. For example, RF front end 530 may include receiver circuitry (RX) 532 and transmitter circuitry (TX) 534. In some aspects, receiver circuitry 532 may communicate with downlink (DL) front end 550, which may include circuitry for receiving radio signals via antenna 335a.

[0064] Similarly, modem 520 may include one or more processors 522 and memory 526 communicating with processor 522. Modem 520 may communicate with RF front end 540. RF front end 540 may include circuitry for transmitting and receiving radio signals. For example, RF front end 540 may include receiving circuitry 542 and transmitting circuitry 544. In some aspects, receiving circuitry 542 may communicate with DL front end 560, which may include circuitry for receiving radio signals via antenna 335b.

[0065] In some aspects, switch 570 may couple transmitting circuitry 534 to uplink (UL) front-end 572. Additionally, switch 570 may couple transmitting circuitry 544 to UL front-end 572. UL front-end 572 may include circuitry for transmitting radio signals via antenna 336. Therefore, when cellular communication circuitry 330 receives an instruction to transmit according to a first RAT (e.g., supported by modem 510), switch 570 may be switched to a first state allowing modem 510 to transmit signals according to the first RAT (e.g., via a transmission chain including transmitting circuitry 534 and UL front-end 572). Similarly, when cellular communication circuitry 330 receives an instruction to transmit according to a second RAT (e.g., supported by modem 520), switch 570 may be switched to a second state allowing modem 520 to transmit signals according to the second RAT (e.g., via a transmission chain including transmitting circuitry 544 and UL front-end 572).

[0066] As described herein, modem 510 may include hardware and software components for implementing the features described above or for UL data used in time-division multiplexing NSA NR operation, as well as various other technologies described herein. For example, processor 512 may be configured to implement some or all of the features described herein by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable storage medium). Alternatively (or in addition), processor 512 may be configured as a programmable hardware element such as a FPGA (Field-Programmable Gate Array) or as an ASIC (Application-Specific Integrated Circuit). Alternatively (or in addition), processor 512 may be configured to implement some or all of the features described herein by combining with one or more of other components 530, 532, 534, 550, 570, 572, 335, and 336.

[0067] Furthermore, as described herein, processor 512 may include one or more processing elements. Therefore, processor 512 may include one or more integrated circuits (ICs) configured to perform the functions of processor 512. Additionally, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of processor 512.

[0068] As described herein, modem 520 may include hardware and software components for implementing the aforementioned features of UL data for time-division multiplexing NSA NR operation, as well as various other techniques described herein. For example, processor 522 may be configured to implement some or all of the features described herein by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable storage medium). Alternatively (or in addition), processor 522 may be configured as a programmable hardware element such as a FPGA (Field-Programmable Gate Array) or as an ASIC (Application-Specific Integrated Circuit). Alternatively (or in addition), processor 522 may be configured to implement some or all of the features described herein by combining one or more of other components 540, 542, 544, 550, 570, 572, 335, and 336.

[0069] Furthermore, as described herein, processor 522 may include one or more processing elements. Therefore, processor 522 may include one or more integrated circuits (ICs) configured to perform the functions of processor 522. Additionally, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of processor 522.

[0070] In 5G NR, a UE can initiate a RACH procedure to gain initial network access. In a four-step contention-based RACH procedure, the UE can send a PRACH to the base station in the first step. The PRACH (also known as Msg1) or PRACH preamble can be one of 64 preambles (long or short) sent during the RACH timing (RO). The UE can power-boost the PRACH after each failed transmission. The UE can transmit the PRACH within a frame using time-frequency resources uniquely associated with its RA-RNTI. For example, the RA-RNTI can be determined based on the index of the first Orthogonal Frequency Division Multiplexing (OFDM) symbol of the PRACH, the index of the first time slot of the PRACH in the transmitted frame, the index of the PRACH in the frequency domain, etc. It is possible for more than one UE to transmit the same PRACH on the same time-frequency resources within a frame.

[0071] The UE can use timing advance (TA) adjustment to transmit PRACH to address propagation delays from the UE to the base station, ensuring that the PRACH is time-aligned with the system frame structure when received by the base station. The UE can automatically obtain its specific TA based on its known location and satellite ephemeris. Alternatively, the base station can broadcast a common TA based on satellite beams or reference points within the cell. The base station can also transmit a UE-specific differential TA to the UE based on network instructions, allowing the UE to derive the complete TA as the sum of the common TA and the differential TA.

[0072] In the second step of the RACH procedure, in response to the PRACH from the UE, the base station can send a RAR (also known as Msg2) or RAR message. The base station can derive the RA-RNTI of the UE transmitting the PRACH from the time-frequency resources carrying the PRACH. The RAR can be scheduled by DCI format 1_0 carried on the Physical Downlink Control Channel (PDCCH) with a CRC scrambled by the RA-RNTI. The UE can attempt to decode the DCI format 1_0 using its RA-RNTI in the common search space of the RAR window. The RAR can also contain a Media Access Control Physical Data Unit (MAC PDU) carried on the Physical Downlink Shared Channel (PDSCH) specified by DCI format 1_0. The subheader of the MAC PDU can contain a 6-bit Random Access Preamble ID (RAPID) or a 4-bit Backoff Indicator (BI). The MAC PDU can contain a 12-bit Timing Advance (TA) command, a 27-bit Uplink Grant, and a 16-bit Temporary Cell-RNTI (TC-RNTI). TC-RNTI can be used by the UE for the remainder of the RACH process.

[0073] A UE can search for the RAR during the common search space of the RAR window. The RAR window can begin after Msg1 and can last for up to 1 frame or 10 ms. Because more than one UE may have already transmitted the same PRACH on the same time-frequency resources in the frame, multiple UEs may attempt to decode DCI format 1_0 of the PDCCH with a CRC scrambled by the same RA-RNTI. Therefore, multiple UEs can decode DCI format 1_0, obtain the MAC PDU of the RAR from the PDSCH specified by DCI format 1_0, and compete for network access.

[0074] In the third step of the RACH procedure, after the UE receives the RAR, the UE can transmit a control element, referred to as Msg3, on the Physical Uplink Shared Channel (PUSCH) allocated by the RAR. The UE can scramble Msg3 using the TC-RNTI received in the RAR. Msg3 may contain the cell-RNTI (C-RNTI), a unique identifier used by the base station to allocate uplink grants to the UE, downlink allocations, etc. If the base station fails to decode Msg3, the base station can reschedule the retransmission of Msg3 using DCI format 0_0 of the PDCCH with a CRC scrambled by the TC-RNTI.

[0075] In the fourth step of the RACH procedure, after the base station decodes Msg3, it can transmit a contention resolution identifier (MAC) control element in Msg4. Msg4 can be carried on a PDSCH specified by DCI format 1_0 with a PDCCH scrambled with a CRC using a TC-RNTI. For a UE that wins the contention but does not yet have a C-RNTI, the TC-RNTI can be promoted to a C-RNTI. If the UE successfully completes the RACH procedure and already has a C-RNTI, it can recover using its C-RNTI and can discard the TC-RNTI received in the RAR. The UE can transmit a Hybrid Automatic Repeat Request Acknowledgment (HARQ-ACK) signal on the PUCCH after decoding Msg4.

[0076] To accelerate the RACH process, 5G NR introduces a 2-step RACH procedure. In the first step of the 2-step RACH procedure, the UE can send a MsgA containing both PRACH and PUSCH. The RACH timing (RO) for PRACH and the PUSCH timing (PO) for PUSCH can have fixed resource mappings. The PO mapping does not overlap with the RO. Configuring the RO for 2-step RACH can be separate from or shared with configuring the RO for 4-step RACH. The PUSCH can contain scrambling sequence initialization values ​​depending on RA-RNTI and RAPID, and a Radio Resource Control (RRC) connection request with or without additional uplink data.

[0077] In the second step of the 2-step RACH procedure, in response to receiving MsgA, the base station can send a RAR called MsgB. MsgB can contain PDCCH and PDSCH. If the PUSCH is successfully received by the base station, the PDSCH contains a successful RAR MAC; otherwise, it contains a backoff RAR MAC. The successful RAR MAC can contain contention resolution ID, TA, C-RNTI, etc. The backoff RAR MAC can contain backoff indicators for the UE to retransmit MsgA and PUSCH. The UE can search for MsgB within the RAR window. The RAR window can start after the MsgA PUSCH transmission and can last for up to 4 frames or 40ms.

[0078] If the UE is in connected mode, the MsgB PDCCH may include DCI format 1_0 with a CRC scrambled by C-RNTI. Otherwise, the CRC of DCI format 1_0 is scrambled by MsgB-RNTI. The UE may attempt to decode DCI format 1_0 of the PDSCH that specifies a successful RAR MAC or a fallback RAR MAC using either MsgB-RNTI or C-RNTI in the RAR window.

[0079] Figure 6This illustration demonstrates a RAR window size expansion based on the DCI field according to one aspect of this disclosure. The RAR window size can be expanded for a 4-step RACH process depending on whether the satellite in the NTN is a LEO or GEO satellite. For LEO satellites, the maximum differential delay can be 3.12 ms and 3.18 ms at satellite altitudes of 600 km and 1200 km, respectively. Since twice the maximum differential delay is less than the nominal 10 ms of the RAR window, expanding the RAR window may not be necessary. However, for GEO satellites, the maximum differential delay between points at the lowest and edge of the coverage area can be 10.3 ms. Expanding the RAR window size may be necessary because twice the maximum differential delay is close to 20 ms, or 2 frames.

[0080] In one aspect, if the RAR window size is extended to 20ms for GEO satellites, the DCI field can indicate the RAR window size extension. In Msg2 transmissions, the CRC of DCI format 1_0 can be scrambled in the common search space by the new NTN-RNTI. Similar to RA-RNTI, the NTN-RNTI can be determined based on the time-frequency resources used to transmit PRACH during the RACH timing. In one aspect, the NTN-RNTI can be determined based on the start symbol index s_id of the PRACH, the start time slot index t_id of the PRACH in the transmitted frame, the frequency domain index f_id, and the uplink carrier ul_carrier_id used to carry the PRACH, but with an additional offset, making the NTN-RNTI different from the MsgB-RNTI of a 2-step RACH process. For example, NTN_RNTI can be equal to (1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id+14×80×8×4). The NTN-RNTI range can be from 35841 to 53760 to avoid conflicts with the RA-RNTI range of 1 to 17920 and the MsgB-RNTI range of 17921 to 35840. When a PRACH triggering DCI format 1_0 is transmitted, DCI format 1_0 also has a field indicating the least significant bit of the system frame number (SFN).

[0081] When transmitting a PRACH, the UE already knows the NTN-RNTI and SFN. Therefore, the UE can use its NTN-RNTI to decode DCI format 1_0. When the UE transmits a PRACH, it can also verify that the bit field in DCI format 1_0 indicating the last bit of the SFN associated with the PRACH that triggered DCI format 1_0 matches the last bit of the SFN. Therefore, the UE can determine whether a RAR received during the extended RAR window is intended for use by that UE, to distinguish it from a RAR intended for use by another UE that transmits a PRACH using the same time-frequency resources but on a different frame. For example, if a UE transmits a PRACH during a frame with SFN x (e.g., an even number of frames), and another UE transmits the same PRACH using the same time-frequency resources during the next frame with SFN x+1 (e.g., an odd number of frames), the CRC of the DCI format 1_0 for the RARs used by both UEs can be scrambled by the same NTN-RNTI in a common search space. However, both DCI formats 1_0 may include fields indicating that the PRACH triggering the two RARs is transmitted on two consecutive frames. Then, a UE transmitting the PRACH on SFN x can verify that the fields in DCI format 1_0 indicate even-numbered frames to determine that DCI format 1_0 is intended for the UE, allowing the UE to receive the correct RAR.

[0082] Figure 7 An RNTI-based RAR window size extension according to another aspect of this disclosure is shown. Similarly, for GEO satellites, the RAR window size is extended to 20 ms. In Msg2 transmissions, the CRC of DCI format 1_0 can be scrambled in the common search space by the new NTN-RNTI. However, with Figure 6 Unlike the RAR window size expansion based on the DCI field, when the PRACH triggering the DCI field is transmitted, the NTN-RNTI here can encode the least significant bit of the SFN. For example, NTN_RNTI can be equal to (1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id+14×80×8×4×(SFN mode 2)). As a result, if the RACH timing is in an even SFN, NTN_RNTI is reduced to RA_RNTI. On the other hand, if the RACH timing is in an odd SFN, NTN_RNTI uses a new value different from RA_RNTI. This avoids conflicts with the MsgB-RNTI value but reuses the RA_RNTI value. That is, for even SFNs, the NTN-RNTI range can be set to [1, 17920] (set 1), and for odd SFNs, the NTN-RNTI range can be set to [35841, 53760] (set 2).

[0083] In one respect, to reuse the range of MsgB-RNTI values, NTN_RNTI can be equal to (1 + s_id + 14 × t_id + 14 × 80 × f_id + 14 × 80 × 8 × ul_carrier_id + 14 × 80 × 8 × 2 × (SFN mode 2)). The range of NTN-RNTI can be [1, 35840] or [1, 17920] for set 1, and [17921, 35840] for set 2. Furthermore, with Figure 6 Unlike the extended RAR window size based on the DCI field, when a PRACH triggering DCI format 1_0 is transmitted, DCI format 1_0 no longer indicates the least significant bit of the system frame number (SFN). The UE can calculate the NTN_RNTI based on its RACH timing time-frequency resources and the SFN at the time of PRACH transmission, and can use the NTN_RNTI to determine whether the RAR received during the extended RAR window is intended for the UE. For example, if a UE transmits a PRACH during a frame with SFN x, and another UE transmits the same PRACH using the same time-frequency resources during the next frame with SFN x+1, the CRC of the DCI format 1_0 of the two UEs' RARs can be scrambled in the common search space by different NTN_RNTIs. The UE transmitting the PRACH on SFN x can then use its corresponding NTN_RNTI to decode the DCI format 1_0 to determine if it is intended for the UE, allowing the UE to receive the correct RAR.

[0084] Figure 8The diagram illustrates a PRACH blind retransmission performed by the UE over multiple frame counts according to another aspect of this disclosure, indicating an expansion of the RAR window size. Similarly, for GEO satellites, the RAR window size is expanded to 20 ms. In Msg1 transmissions, the UE transmits multiple (e.g., two) PRACH transmissions at the same RACH timings repeated over multiple frames (using the same time-frequency resources). In one aspect, the transmission power of the PRACH retransmissions can be gradually increased or remain constant. The preamble power boost counter can be incremented by 1 or the number of PRACH blind retransmissions can be increased. The same RA-RNTI is obtained from each of the PRACH retransmissions. That is, RA-RNTI can be equal to (1 + s_id + 14 × t_id + 14 × 80 × f_id + 14 × 80 × 8 × ul_carrier_id). In one aspect, RACH timings are paired across multiple (e.g., two) consecutive frames. For example, each UE can transmit PRACH on two consecutive frames, with the first PRACH in an even-numbered SFN (SFN x) and the second PRACH in an odd-numbered SFN (SFN x+1). This avoids single-frame interleaved PRACH transmissions from two different UEs. Each UE can wait to receive RAR messages within its own 20ms RAR window by utilizing its unique RA-RNTI decoding of DCI format 1_0.

[0085] Figure 9 Different locations of the DCI CRC are shown using RA-RNTI to mask the DCI CRC according to another aspect of this disclosure. Similarly, for GEO satellites, the RAR window size is extended to 20 ms. In Msg2 transmissions, when a PRACH triggering DCI format 1_0 is transmitted, different subsets of the CRC of DCI format 1_0 can be scrambled with RA-RNTI in the common search space based on the number of frames. RA-RNTI can be equal to (1 + s_id + 14 × t_id + 14 × 80 × f_id + 14 × 80 × 8 × ul_carrier_id). If the last 16 bits of the CRC of DCI format 1_0 are scrambled with RA-RNTI, also known as masking the last 16 bits of the CRC of DCI format 1_0 with RA-RNTI, then DCI format 1_0 corresponds to a PRACH transmitted using RACH timing in even-numbered SFNs. If the penultimate 16 bits of the CRC of DCI format 1_0 are scrambled by RA-RNTI, also known as masking the penultimate 16 bits of the CRC of DCI format 1_0 with RA-RNTI, then RAR corresponds to PRACH transmitted using RACH timing in odd SFN.

[0086] The UE can calculate the RA-RNTI based on its time-frequency resources for RACH timing and determine the SFN when it transmits PRACH. The UE can use the least significant bit of the SFN to determine which 16 bits of the CRC of DCI format 1_0 received during the extended RAR window should be decoded using the RN-RNTI to determine if the RAR is intended for the UE. For example, if a UE transmits PRACH during a frame with SFN x, and another UE transmits the same PRACH using the same time-frequency resources during the next frame with SFN x+1, different subsets of the CRC of the DCI format 1_0 for the RARs of the two UEs can be scrambled by the same RA-RNTI in the common search space. The UE transmitting PRACH on SFN x can then decode the last 16 CRC bits of the DCI format 1_0 to determine if the DCI format 1_0 is intended for the UE, allowing the UE to receive the correct RAR.

[0087] In one aspect, the RAR window offset of the RACH procedure can be modified. The RAR window offset can be modified for both 4-step and 2-step RACH procedures. In one aspect, in a unified design, the common timing advance (TA) based on a satellite beam or reference point in the cell can be used as the RAR window offset for all UEs. In another aspect, the common TA is used as the RAR window offset for all UEs without location information. A UE can transmit Msg1 in a 4-step RACH procedure or MsgA in a 2-step RACH procedure with a common TA. In another aspect, the full TA, taking into account the UE-specific propagation delay, can be set as the RAR window offset for UEs with location information. A UE can transmit Msg1 or MsgA with the full TA.

[0088] In one aspect, for a 2-step RACH procedure, the base station can blindly retransmit MsgB within a nominal 40ms RAR window to maintain reliable transmission of MsgB for NTN. This is because for NTN, large propagation delays can make HARQ-ACK retransmissions within the RAR window difficult. MsgB-RNTI can be set to equal (1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id+14×80×8×2). In another aspect, the number of blind retransmissions and / or the retransmission mode can depend on the PRACH reception conditions or the PUSCH reception conditions. In yet another aspect, the retransmission mode can be pre-configured.

[0089] In one aspect, due to the long propagation delay associated with NTN, the base station can extend the values ​​of K1 and K2, which determine the delay between uplink and downlink transmissions, to align with Time Domain Duplex (TDD) uplink-downlink configurations. For example, K1 can be a time slot in units between the PDSCH and the corresponding PUCCH with HARQ feedback. K1 can be indicated by the parameter "dl-DataToUL-ACK" in the information element "PUCCH-config". The nominal maximum value of K1 can be 15 time slots. K2 can be a time slot in units between DCI reception and the corresponding PUSCH scheduled by the DCI. K2 can be indicated by the parameter "k2" in the information element "PUSCH-TimeDomain ResourceAllocation". The nominal maximum value of K2 can be 32 time slots. The transmission times of PUSCH and PUCCH scheduled by the DCI can be indicated by K1 and K2.

[0090] Figure 10 This illustrates the timing relationship between the base station and the UE in the NTN, based on the round-trip propagation delay between the base station and the UE, using advance timing adjustments to the UE. In the NTN, the additional offset K can be... 偏移 Add to PUSCH or PUCCH transmissions. For example, in Figure 10 In this configuration, the one-way propagation delay between the UE and the base station is 4 time slots, resulting in a round-trip propagation delay of 8 time slots. Therefore, TA can be set to 8 time slots. When the DCI used for uplink granting is in time slot 0 and K2 is set to 2 by the DCI, due to the 8-time-slot round-trip propagation delay, the scheduled PUSCH may not be received by the base station until time slot 10. Additional offset K 偏移 It can be used to adjust PUSCH. However, depending on the additional time offset K... 偏移 The resulting time slots used for PUSCH or PUCCH transmissions can be aligned with the downlink time slots. In one aspect, to align delayed PUSCH or PUCCH transmissions with uplink time slots, the maximum value of K1 can be extended to 31 time slots, and the maximum value of K2 can be extended to 64 time slots.

[0091] In one aspect, the base station can broadcast a new RAR window value to the UE to expand the RAR window size based on whether the satellite is LEO, GEO, or other satellites. In another aspect, the base station can use System Information Block Type 1 (SIB1) to broadcast a new RAR window value. In yet another aspect, a new SIB1 information element can be used, or the current information element, such as "RACHConfigCommon IE", can be used by adding a new element for NTN.

[0092] In one respect, the new RAR window value can be set to the same value. In another respect, the RAR window value can be set based on the tracking area, which can be linked to the type of satellite used. In yet another respect, the RAR window value can be set based on the current load and network processing capacity to ensure that other parameters are also appropriately scaled. This can include estimates of how long the delay in responding to the network might be for MsgB in a 2-step RACH process or for Msg2 / 4 in a 4-step RACH process, and what actions the UE can take during the intermediate sleep duration.

[0093] In one aspect, base stations can use paging messages to multicast new RAR window size values. Because paging messages are less frequent than SIB1 messages used for broadcasting, the network may not be able to respond to significant spikes in network access traffic. It may be necessary to increase the paging message size to include additional information about the new RAR window size value. However, network efficiency can be achieved because only the target UE of the paging message will utilize the additional information elements, rather than all UEs in the NTN modifying their RACH behavior. In one aspect, paging messages can be restricted to downlink traffic only, so that UEs capable of performing RACH procedures due to uplink traffic do not need to utilize this enhancement. In one aspect, any downlink paging targeting a UE can carry the new window size value instead of using multicast across all UEs. In one aspect, paging messages can be restricted to UEs that meet a specific International Mobile Subscriber Identity (IMSI).

[0094] Figure 11 This is a data flow diagram illustrating an example of a method for a UE to transmit a PRACH preamble to a base station and receive RAR messages from the base station on an extended RAR window to perform a RACH procedure, according to some aspects of this disclosure.

[0095] At operation 1101, the UE transmits a PRACH preamble to the NTN base station during a frame period that includes a frame structure of multiple frames to request access to the NTN.

[0096] At operation 1103, the UE receives a Random Access Response (RAR) message from the base station during the RAR window, where the RAR window spans multiple frames of the frame structure.

[0097] At operation 1105, the UE determines whether a RAR message received from the base station is intended for use by the UE based on the indication in the downlink control information (DCI) of the scheduled RAR message.

[0098] Figure 12This is a flowchart illustrating an example of a method for a base station for NTN to receive a PRACH preamble from a UE, determine an RNTI, and transmit a RAR to the UE on an extended RAR window based on the RNTI, according to some aspects of this disclosure.

[0099] At operation 1201, the base station receives a PRACH preamble from the UE during a frame that includes a frame structure of multiple frames to request access to the NTN.

[0100] At operation 1203, the base station determines the RNTI based on the time-frequency resources of the frame used to carry the PRACH preamble.

[0101] At operation 1205, the base station transmits a DCI (Distributed Controlled Instruction) for scheduling RAR messages during a RAR window spanning multiple frames. The DCI includes an indication that allows the UE to determine the intended use of the RAR message for the UE based on the RNTI (Real-Timer Indicator) and the number of frames used to carry the PRACH preamble.

[0102] The aspects of the methods and apparatus described herein for enhancing the RACH process in wireless communication networks can be implemented, for example, in a data processing system via a network computer, network server, tablet computer, smartphone, laptop computer, desktop computer, other consumer electronic device, or other data processing system. Specifically, the operations are digital signal processing operations performed by a processor executing instructions stored in one or more memories. The processor can read stored instructions from the memory and execute the instructions to perform the operations. These memories represent examples of machine-readable, non-transitory storage media that can store or contain computer program instructions that, when executed, cause the data processing system to perform one or more methods described herein. The processor can be a processor in a local device such as a smartphone, a processor in a remote server, or a distributed processing system of multiple processors in a local device and a remote server, wherein their respective memories contain portions of the instructions required to perform the operations.

[0103] While certain exemplary examples are described and illustrated in the accompanying drawings, it should be understood that these examples are merely illustrative and not limiting to the broader aspects of the invention, and this disclosure is not limited to the specific constructions and arrangements shown and described, as various other modifications may be made by those skilled in the art. Therefore, the description is to be regarded as exemplary and not restrictive.

Claims

1. A method performed by a radio user equipment (UE) in a non-terrestrial communication network, the method comprising: The UE transmits a Physical Random Access Channel (PRACH) preamble to the base station of the non-terrestrial communication network during a frame that includes a frame structure of multiple frames in order to request access to the non-terrestrial communication network. The UE receives a RAR message from the base station during a Random Access Response (RAR) window, wherein the RAR window spans two frames of the frame structure; as well as The UE determines whether the RAR message received from the base station is intended for use by the UE based on an indication in the downlink control information (DCI) that schedules the RAR message, wherein determining that the RAR message is intended for use by the UE includes: The UE determines the Radio Network Temporary Identifier (RNTI) based on the time-frequency resources of the frame used to transmit the PRACH preamble. The cyclic redundancy check (CRC) of the DCI in the RAR message detected by the UE is scrambled by the RNTI; and The UE determines that the field in the DCI identifies the frame number that triggers the PRACH associated with the RAR as an even or odd frame, and that the frame number matches the frame used by the UE to transmit the PRACH preamble.

2. The method of claim 1, wherein the transmission of the PRACH preamble by the UE comprises: The PRACH preamble is repeatedly transmitted using the same time-frequency resources of multiple frames of the frame structure.

3. The method of claim 2, wherein repeatedly transmitting the PRACH preamble using the same time-frequency resources of multiple frames comprises: The PRACH preamble is transmitted at increased power on the multiple frames; as well as Increase the number of repeated PRACH preamble transmissions by incrementing the preamble power boost counter.

4. The method of claim 1, wherein the CRC of the DCI of the RAR message detected by the UE is scrambled by the RNTI, comprising: The CRC of the DCI of the RAR message detected by the UE is scrambled by the RNTI, wherein the scrambled portion of the CRC of the DCI is identified by the frame number of the frame used by the UE to transmit the PRACH preamble.

5. The method of claim 1, wherein the start of the RAR window is offset from the end of the transmission of the PRACH preamble by a timing advance (TA) value, the TA value being adapted to align the frame structure between the UE and the base station.

6. The method according to claim 5, further comprising: The UE receives the TA value from the base station, wherein the TA value assumes that the UE is located in a common reference location within the coverage area of ​​the base station.

7. The method of claim 6, wherein the transmission of the PRACH preamble by the UE comprises: Transmit the PRACH preamble with the TA value.

8. The method according to claim 5, further comprising: The TA value is determined by the UE based on the UE's location. And the PRACH preamble transmitted by the UE includes: Transmit the PRACH preamble with the TA value.

9. A baseband processor for a radio user equipment (UE), the baseband processor being configured to perform operations including: During a frame that comprises multiple frames, a Physical Random Access Channel (PRACH) preamble is transmitted to a base station of a non-terrestrial communication network to request access to the non-terrestrial communication network. During the Random Access Response (RAR) window, a RAR message is received from the base station, wherein the RAR window spans two frames of the frame structure; as well as Determining whether the RAR message received from the base station is intended for use by the UE based on the indication in the downlink control information (DCI) of the RAR message, wherein determining that the RAR message is intended for use by the UE includes: The Radio Network Temporary Identifier (RNTI) is determined based on the time-frequency resources of the frame used to transmit the PRACH preamble. The cyclic redundancy check (CRC) of the DCI in the detection of the RAR message is scrambled by the RNTI; and The field in the DCI is determined to identify the frame number that triggers the PRACH associated with the RAR as either an even or odd frame, and wherein the frame number matches the frame used by the UE to transmit the PRACH preamble.

10. The baseband processor of claim 9, wherein transmitting the PRACH preamble by the UE comprises: The PRACH preamble is repeatedly transmitted using the same time-frequency resources of multiple frames of the frame structure.

11. The baseband processor of claim 10, wherein repeatedly transmitting the PRACH preamble using the same time-frequency resources of multiple frames comprises: The PRACH preamble is transmitted at increased power on the multiple frames; as well as Increase the number of repeated PRACH preamble transmissions by incrementing the preamble power boost counter.

12. The baseband processor of claim 9, wherein the operation of detecting the CRC of the DCI of the RAR message scrambled by the RNTI includes the following operations: The detection of a portion of the CRC of the DCI of the RAR message is scrambled by the RNTI, wherein the scrambled portion of the CRC of the DCI is identified by the frame number of the frame used by the UE to transmit the PRACH preamble.

13. The baseband processor of claim 9, wherein the start of the RAR window is offset from the end of the transmission of the PRACH preamble by a timing advance (TA) value, the TA value being adapted to align the frame structure between the UE and the base station.

14. The baseband processor of claim 13, wherein the operation further comprises: The TA value is received from the base station, wherein the TA value assumes that the UE is located in a common reference location within the coverage area of ​​the base station.

15. The baseband processor of claim 14, wherein the operation for transmitting the PRACH preamble includes the following operations: Transmit the PRACH preamble with the TA value.

16. The baseband processor of claim 13, wherein the operation further comprises: The TA value is determined based on the location of the UE. And the operation for transmitting the PRACH preamble includes the following operations: Transmit the PRACH preamble with the TA value.

17. A user equipment (UE) device, the UE device comprising: At least one antenna; At least one radio component, wherein the at least one radio component is configured to communicate with a base station of a non-terrestrial communication network using the at least one antenna; as well as At least one processor, coupled to the at least one radio component, wherein the at least one processor is configured to perform operations including: During a frame that comprises multiple frames, a Physical Random Access Channel (PRACH) preamble is transmitted to a base station of a non-terrestrial communication network to request access to the non-terrestrial communication network. During a Random Access Response (RAR) window, a RAR message is received from the base station, wherein the RAR window spans multiple frames of the frame structure; and Determining whether the RAR message received from the base station is intended for use by the UE based on the indication in the downlink control information (DCI) of the RAR message, wherein determining that the RAR message is intended for use by the UE includes: The UE determines the Radio Network Temporary Identifier (RNTI) based on the time-frequency resources of the frame used to transmit the PRACH preamble. The cyclic redundancy check (CRC) of the DCI in the RAR message detected by the UE is scrambled by the RNTI; and The UE determines that the field in the DCI identifies the frame number that triggers the PRACH associated with the RAR as an even or odd frame, and that the frame number matches the frame used by the UE to transmit the PRACH preamble.

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