Methods and apparatuses for wireless communication

Abstract

Provided are methods and apparatuses for wireless communication. A method comprises: a terminal device receiving a first SSB; and the terminal device sending a first random access channel on a first RO corresponding to a first transmit beam, wherein the first SSB is from a network device in an NTN, the first transmit beam corresponds to a first receive beam of the network device, the first receive beam is used for the network device to determine a first time period, and the first time period is used for the network device to monitor the first random access channel by means of using the first receive beam.

Description

Methods and apparatus for wireless communication Technical Field

[0001] This application relates to the field of communication technology, and more specifically, to a method and apparatus for wireless communication. Background Technology

[0002] Compared to terrestrial networks, non-terrestrial networks (NTNs) have longer transmission periods and wider frequency ranges for the synchronization signal (SS) / physical broadcast channel (PBCH), and also suffer from significant Doppler shift. Therefore, optimizing cell search and random access in NTN scenarios becomes a crucial technical challenge. Summary of the Invention

[0003] This application provides a method and apparatus for wireless communication. The various aspects related to the embodiments of this application are described below.

[0004] In a first aspect, a method for wireless communication is provided, comprising: a terminal device receiving a first synchronization signal block (SS / PBCH block, SSB); the terminal device transmitting a first random access channel on a first random access channel occasion (RACH occasion, RO) corresponding to a first transmit beam; wherein the first SSB originates from a network device in an NTN, the first transmit beam corresponds to a first receive beam of the network device, the first receive beam is used by the network device to determine a first time period, and the first time period is used by the network device to listen to the first random access channel through the first receive beam.

[0005] In a second aspect, a method for wireless communication is provided, comprising: a network device transmitting a plurality of SSBs, the plurality of SSBs including a first SSB received by a terminal device; the network device listening to a first random access channel during a first time period via a first receiving beam; wherein the network device belongs to an NTN, the first receiving beam is used by the network device to determine the first time period, the first receiving beam corresponds to a first transmitting beam of the terminal device, and the first random access channel is transmitted on a first RO corresponding to the first transmitting beam.

[0006] Thirdly, an apparatus for wireless communication is provided, the apparatus being a terminal device, the apparatus comprising: a receiving unit for receiving a first SSB; and a transmitting unit for transmitting a first random access channel on a first RO corresponding to a first transmit beam; wherein the first SSB originates from a network device in an NTN, the first transmit beam corresponds to a first receive beam of the network device, the first receive beam is used by the network device to determine a first time period, and the first time period is used by the network device to listen to the first random access channel through the first receive beam.

[0007] Fourthly, an apparatus for wireless communication is provided, the apparatus being a network device, the apparatus comprising: a transmitting unit for transmitting a plurality of SSBs, the plurality of SSBs including a first SSB received by a terminal device; and a receiving unit for listening to a first random access channel via a first receiving beam during a first time period; wherein the network device belongs to an NTN, the first receiving beam is used by the network device to determine the first time period, the first receiving beam corresponds to a first transmitting beam of the terminal device, and the first random access channel is transmitted on a first RO corresponding to the first transmitting beam.

[0008] Fifthly, a communication device is provided, including a memory and a processor, the memory for storing a program, and the processor for calling the program in the memory to perform the method as described in the first or second aspect.

[0009] A sixth aspect provides an apparatus including a processor for calling a program from memory to perform the method as described in the first or second aspect.

[0010] A seventh aspect provides a chip including a processor for calling a program from memory, causing a device on which the chip is mounted to perform the method as described in the first or second aspect.

[0011] Eighthly, a computer-readable storage medium is provided having a program stored thereon that causes a computer to perform the method as described in the first or second aspect.

[0012] Ninth aspect, a computer program product is provided, including a program that causes a computer to perform the method as described in the first or second aspect.

[0013] In a tenth aspect, a computer program is provided that causes a computer to perform the method as described in the first or second aspect.

[0014] The terminal device in this embodiment can receive a first SSB and transmit a first random access channel on a first RO corresponding to the first transmit beam. The first transmit beam and the first receive beam of the network device receiving the first random access channel form a beam pair. The first receive beam can be used by the network device to determine a first time period for monitoring the first random access channel, which helps to reduce the power consumption of the network device and improve the random access success rate under the SSB extension period. Attached Figure Description

[0015] Figure 1 shows the wireless communication system used in an embodiment of this application.

[0016] Figure 2 shows an NTN system used in an embodiment of this application.

[0017] Figure 3 shows another NTN system used in an embodiment of this application.

[0018] Figure 4 is a flowchart illustrating a method for wireless communication provided in an embodiment of this application.

[0019] Figure 5 is a schematic diagram of one possible implementation of the method shown in Figure 4.

[0020] Figure 6 is a schematic diagram of a device for wireless communication provided in an embodiment of this application.

[0021] Figure 7 is a schematic diagram of another device for wireless communication provided in an embodiment of this application.

[0022] Figure 8 is a schematic diagram of the structure of a communication device provided in an embodiment of this application. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0024] The embodiments of this application can be applied to various communication systems. For example, the embodiments of this application can be applied to Global System for Mobile Communication (GSM), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA), General Packet Radio Service (GPRS), Long Term Evolution (LTE), Advanced Long Term Evolution (LTE-A), New Radio (NR), evolution systems of NR, LTE-based access to unlicensed spectrum (LTE-U), NR-based access to unlicensed spectrum (NR-U), Universal Mobile Telecommunications System (UMTS), Wireless Local Area Networks (WLAN), Wireless Fidelity (WiFi), and 5th-generation (5G) systems. The embodiments of this application can also be applied to other communication systems, such as 6th-generation (6G) mobile communication systems, or future communication systems such as satellite communication systems.

[0025] Traditional communication systems support a limited number of connections and are easy to implement. However, with the development of communication technology, communication systems can support not only traditional cellular communication but also one or more other types of communication. For example, a communication system can support one or more of the following communication methods: device-to-device (D2D) communication, machine-to-machine (M2M) communication, machine-type communication (MTC), enhanced machine-type communication (eMTC), vehicle-to-vehicle (V2V) communication, and vehicle-to-everything (V2X) communication. The embodiments of this application can also be applied to communication systems that support the above-mentioned communication methods.

[0026] The communication system in this application embodiment can be applied to carrier aggregation (CA) scenarios, dual connectivity (DC) scenarios, and standalone (SA) network deployment scenarios.

[0027] The communication system in this application embodiment can be applied to unlicensed spectrum. This unlicensed spectrum can also be considered a shared spectrum. Alternatively, the communication system in this application embodiment can also be applied to licensed spectrum. This licensed spectrum can also be considered a dedicated spectrum.

[0028] The embodiments of this application can be applied to NTN systems. As an example, the NTN system can be a 4G-based NTN system, an NR-based NTN system, an Internet of Things (IoT)-based NTN system, or a narrowband Internet of Things (NB-IoT)-based NTN system.

[0029] A communication system may include one or more terminal devices. The terminal devices mentioned in the embodiments of this application may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent, or user device, etc.

[0030] In some embodiments, the terminal device may be a station (ST) in a WLAN. In some embodiments, the terminal device may be a cellular phone, cordless phone, session initiation protocol (SIP) phone, wireless local loop (WLL) station, personal digital assistant (PDA) device, handheld device with wireless communication capabilities, computing device or other processing device connected to a wireless modem, in-vehicle device, wearable device, terminal device in a next-generation communication system (e.g., NR system), or terminal device in a future public land mobile network (PLMN) network, etc.

[0031] In some embodiments, the terminal device may be a device that provides voice and / or data connectivity to a user. For example, the terminal device may be a handheld device, an in-vehicle device, etc., with wireless connectivity. As some specific examples, the terminal device may be a mobile phone, tablet, laptop, PDA, mobile internet device (MID), wearable device, virtual reality (VR) device, augmented reality (AR) device, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical surgery, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, etc.

[0032] In some embodiments, the terminal device may be deployed on land. For example, the terminal device may be deployed indoors or outdoors. In some embodiments, the terminal device may be deployed on water, such as on a ship. In some embodiments, the terminal device may be deployed in the air, such as on an airplane, balloon, or satellite.

[0033] In addition to terminal devices, the communication system may also include one or more network devices. In this embodiment, the network device can be a device for communicating with the terminal device; this network device may also be referred to as an access network device or a radio access network device. For example, the network device may be a base station. In this embodiment, the network device may refer to a radio access network (RAN) node (or device) that connects the terminal device to the wireless network. A base station can broadly encompass, or be replaced by, various names including: NodeB, evolved NodeB (eNB), next-generation NodeB (gNB), relay station, access point, transmitting and receiving point (TRP), transmitting point (TP), master station (MeNB), secondary station (SeNB), multi-mode radio (MSR) node, home base station, network controller, access node, radio node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), positioning node, etc. A base station can be a macro base station, micro base station, relay node, donor node, or similar entities, or combinations thereof. A base station can also refer to a communication module, modem, or chip installed within the aforementioned equipment or apparatus. A base station can also be a mobile switching center, a device that performs base station functions in D2D, V2X, and M2M communications, a network-side device in a 6G network, or a device that performs base station functions in future communication systems. A base station can support networks using the same or different access technologies. The embodiments of this application do not limit the specific technologies or device forms used in the network equipment.

[0034] Base stations can be fixed or mobile. For example, a helicopter or drone can be configured to act as a mobile base station, and one or more cells can move depending on the location of the mobile base station. In other examples, a helicopter or drone can be configured as a device to communicate with another base station.

[0035] In some deployments, the network device in this application embodiment may refer to a CU or a DU, or the network device may include both a CU and a DU. The gNB may also include an AAU.

[0036] By way of example and not limitation, in the embodiments of this application, the network device may have mobility characteristics; for example, the network device may be a mobile device. In some embodiments of this application, the network device may be a satellite or a balloon station. In some embodiments of this application, the network device may also be a base station located on land, water, or other similar locations.

[0037] In this embodiment, the network device can provide services to a cell. The terminal device communicates with the network device through the transmission resources (e.g., frequency domain resources, or spectrum resources) used by the cell. The cell can be the cell corresponding to the network device (e.g., a base station). The cell can belong to a macro base station or to a base station corresponding to a small cell. The small cell can include: metro cell, micro cell, pico cell, femto cell, etc. These small cells have the characteristics of small coverage area and low transmission power, and are suitable for providing high-speed data transmission services.

[0038] For example, FIG1 is a schematic diagram of the architecture of a wireless communication system provided in an embodiment of this application. The wireless communication system 100 shown in FIG1 includes a network device and multiple terminal devices. The network device 110 can provide communication coverage for a specific geographical area and can communicate with terminal devices located within the coverage area. The multiple terminal devices are, for example, terminal devices 120a to 120j in FIG1.

[0039] Optionally, the wireless communication system 100 shown in FIG1 may further include multiple network devices and each network device may include other number of terminal devices within its coverage area. This application embodiment does not limit this.

[0040] For example, Figure 2 is a schematic diagram of an architecture of the NTN system mentioned above. The NTN system 200 shown in Figure 2 uses satellite 210 as an airborne platform. As shown in Figure 2, the satellite radio access network includes satellite 210, service link 220, feeder link 230, terminal equipment 240, gateway (GW) 250, and network 260 including base stations and core network.

[0041] Satellite 210 is a spacecraft based on a space platform. Service link 220 refers to the link between satellite 210 and terminal equipment 240. Feeder link 230 refers to the link between gateway 250 and satellite 210. The Earth-based gateway 250 connects satellite 210 to the base station or core network, depending on the NTN architecture chosen.

[0042] The NTN architecture shown in Figure 2 is a bend-tube transponder architecture. In this architecture, the base station is located on Earth behind gateway 250, and satellite 210 acts as a relay. Satellite 210 operates as a relay that forwards signals from feeder link 230 to serving link 220, or forwards signals from serving link 220 to feeder link 230. That is, satellite 210 does not have the function of a base station; communication between terminal device 240 and the base station in network 260 needs to be relayed through satellite 210.

[0043] For example, Figure 3 is a schematic diagram of another architecture of the NTN system. As shown in Figure 3, the satellite radio access network 300 includes a satellite 310, a service link 320, a feeder link 330, a terminal device 340, a gateway 350, and a network 360. Unlike Figure 2, the satellite 310 has a base station 312, and the network 360 behind the gateway 350 only includes the core network.

[0044] Figure 3 shows the NTN architecture, which is a regenerative transponder architecture. In this architecture, satellite 310 carries base station 312, which can be directly connected to the Earth-based core network via a link. Satellite 310 has the function of a base station, and terminal device 340 can communicate directly with satellite 310. Therefore, satellite 310 can be referred to as a network device.

[0045] The communication system with the architecture shown in Figures 2 and 3 may include multiple network devices, and each network device may include other terminal devices within its coverage area. This application embodiment does not limit this.

[0046] In the embodiments of this application, the communication system shown in Figures 1 to 3 may also include other network entities such as a mobility management entity (MME) and an access and mobility management function (AMF), which are not limited in this embodiment.

[0047] It should be understood that devices with communication functions in the network / system of this application embodiment can be referred to as communication devices. Taking the communication system 100 shown in FIG1 as an example, the communication device may include a network device 110 and a terminal device 120 with communication functions. The network device 110 and the terminal device 120 can be the specific devices described above, which will not be repeated here. The communication device may also include other devices in the communication system 100, such as network controllers, mobility management entities, and other network entities. This application embodiment does not limit this.

[0048] To facilitate understanding, some related technical knowledge involved in the embodiments of this application is first introduced. The following related technologies are optional solutions and can be arbitrarily combined with the technical solutions of the embodiments of this application, all of which fall within the protection scope of the embodiments of this application. The embodiments of this application include at least some of the following contents.

[0049] With the development of communication technologies, communication systems (such as 5G) will integrate the market potential of satellite and terrestrial network infrastructure. For example, the 5G standard makes NTN, including satellite segments, part of the recognized 3rd generation partnership project (3GPP) 5G connectivity infrastructure.

[0050] NTN refers to a network or network segment that uses radio frequency (RF) resources on spacecraft (e.g., satellites) or unmanned aerial system (UAS) platforms. Satellites are classified according to their orbital altitude, including low Earth orbit (LEO), medium Earth orbit (MEO), geostationary Earth orbit (GEO), and highly elliptical orbit (HEO). LEO is a geocentric orbit with an altitude of 2000 km or less, or at least 11.25 cycles per day, with an eccentricity of less than 0.25. Most man-made objects in outer space are located in LEO. LEO satellites orbit the Earth at high speeds (mobility), but in predictable or deterministic orbits.

[0051] Satellites at different orbital altitudes have different orbital periods. For example, typical LEO altitudes are 250-1500 km with orbital periods of 90-120 minutes; typical MEO altitudes are 5000-25000 km with orbital periods of 3-15 hours; and GEO altitudes are approximately 35786 km with orbital periods of 24 hours.

[0052] As shown in Figures 2 and 3 above, which use satellite as an example, typical scenarios for terminal devices accessing the NTN system involve either a transparent NTN payload or a regenerative NTN payload. Specifically, the bent-tube transponder architecture shown in Figure 2 corresponds to a transparent NTN payload, with the satellite or UAS platform acting as a relay; the regenerative transponder architecture shown in Figure 3 corresponds to a regenerative NTN payload, with a base station on the satellite or UAS platform. In the network architectures shown in Figures 2 and 3, the base station can involve various communication systems, such as NB-IoT.

[0053] In NTN systems, terminal devices communicate with network equipment via satellite or airborne platforms. Satellites and other airborne platforms cover a larger area; therefore, the number of terminal devices served within an NTN cell is typically much greater than in a terrestrial network (TN) cell. In NTN systems, enhancing uplink (UL) / downlink (DL) capacity and coverage, and improving spectrum utilization efficiency are worthwhile research topics.

[0054] Since satellites cannot transmit all beams simultaneously, they typically use periodic beam switching (beam hopping) to cover different areas. In other words, to meet the traffic demands of wide-area users, satellites can communicate based on beam hopping or beam switching. Specifically, satellites can periodically activate different beams in different areas / directions to achieve area coverage.

[0055] In a communication system, the transmission of the SS / PBCH can be used by terminal equipment for cell search and random access. The SS / PBCH can be carried within a Synchronization Signal / Physical Broadcast Channel Block (SS / PBCH block, SSB). This Synchronization Signal / Physical Broadcast Channel Block can be simply referred to as the Synchronization Signal Block. For simplicity, this embodiment uses SSB to represent the SS / PBCH block.

[0056] SSB can achieve wide-area transmission through beamforming technology. That is, the satellite (network side) can cover a larger area using a low-gain, wide-angle beam, and can also improve transmission and reception performance through beam adjustment. For example, for LEO satellites, due to their high-speed movement (approximately 7.5 km / s), the beam needs to be adjusted over time to track terminal devices. Furthermore, the network side can dynamically adjust the narrow beam based on feedback from the terminal device's channel state information-reference signal (CSI-RS) or sounding reference signal (SRS) results. In NTN scenarios, high-speed moving LEO satellites require frequency offset correction; pointing based on a narrow beam can reduce Doppler effects and improve reception performance.

[0057] It should be noted that in NTN systems, the transmission period of SSBs can be 160ms or longer, depending on the multiplexing mode of the SSB and the control resource set (CORESET). To support beam hopping in NTN, the system can support the assumption of period extension for SSB transmission during initial access by the terminal device. The maximum value of the additional default value for period extension can be 160ms or 320ms. For example, when the periodicity of SSBs is extended in half-frame granularity, the network side can support at least one SSB transmission within one half-frame.

[0058] In some implementations, terminal devices can perform cell search and cell selection by measuring SSBs for cell access or cell handover. For example, SSBs can be used for initial cell search. During the cell search process, the terminal device supports half-frames with SSBs occurring at a period of 160ms. Since the period between consecutive SSBs is longer than the default period (20ms) of terrestrial networks, the terminal device searching for NR carriers must remain on each possible frequency for a longer time. Alternatively, the terminal device can be allowed to use stored information to support the cell selection process. Stored information can include carrier frequencies previously camped by the terminal device, as well as previously received measurement control information or previously detected cell parameters. In the case of cell selection after leaving radio resource control (RRC) connection mode, the network device can use an RRC release message to direct the terminal device to a specific carrier. If cell selection based on stored information is unsuccessful, the terminal device needs to use the initial cell selection process. If a new default SSB period is introduced on top of the existing default of 20ms, the default value actually used in the network can be stored in the terminal device as part of the stored information to simplify the cell search and cell selection process.

[0059] In some implementations, the terminal device can transmit the Physical Random Access Channel (PRACH) based on one or more received SSBs. For example, during random access, the terminal device can use the association information between the SSB and PRACH resources to determine the timing of PRACH transmission, i.e., the PRACH timing. The PRACH timing can also be called the Random Access Channel timing (RO). In the relevant 3GPP specifications, the RO is mapped to the SSB, and the association period starts from frame 0. That is, the RO is configured starting from radio frame 0. Furthermore, the association information between the SSB and PRACH resources can also be used to select a preamble. Taking the NR specification as an example, network devices typically configure a certain number of contention preambles for each SSB. When the terminal device selects a particular SSB for access, it should randomly select one from the preamble set corresponding to that SSB.

[0060] For the longer-period SSB transmissions in NTNs, terminal devices face numerous challenges when searching for cells. For example, the SSB transmission period in terrestrial networks is 20ms; to support beam switching, satellites in NTNs transmit SSBs with even longer transmission periods (e.g., 160ms), increasing cell search time. Furthermore, compared to terrestrial networks, satellite-transmitted SSBs may cover a wider (sparser) frequency range, increasing frequency domain search complexity. Additionally, in certain scenarios (e.g., LEO scenarios), Doppler shift has a significant impact, requiring additional frequency offset compensation from the terminal device. Moreover, the terminal device may not have stored any previous network information, necessitating scanning the entire frequency band and further increasing search time.

[0061] Furthermore, terminal devices face numerous challenges when performing random access within an NTN. For instance, because the SSB period may be extended to 160ms to support beam hopping, network devices may be unable to monitor all configured ROs within the SSB period, thus impacting the success rate of random access. To ensure efficient PRACH monitoring across large coverage areas and under beam hopping mechanisms, while also considering the energy-saving mechanisms of terminal devices, new mechanisms are needed to coordinate the terminal device's strategy for sending preambles via PRACH and the network device's management of received UL beams. As another example, in the case of beam hopping, for a given RO, its time and frequency resources may overlap with ROs associated with SSBs transmitting within different beam coverage areas. If the number of beam footprints with overlapping ROs exceeds the number of uplink received active beams, the network device cannot detect PRACH from all beam footprints.

[0062] In summary, how terminal devices in an NTN system can perform random access and cell search based on beam hopping is a technical problem that needs to be solved.

[0063] To address the aforementioned issues, this application proposes a method for wireless communication. Through this method, a terminal device can receive a first SSB and transmit a first random access channel on a first RO corresponding to a first transmit beam. The first transmit beam and the first receive beam from which the network device receives the first random access channel form a beam pair. The first receive beam can be used by the network device to determine a first time period for monitoring the first random access channel, which helps reduce network device power consumption and improve the random access success rate under the SSB extension period.

[0064] To facilitate understanding, the method proposed in the embodiments of this application will be described in detail below with reference to Figure 4. Figure 4 is presented from the perspective of the interaction between the first terminal device and the network device.

[0065] The terminal device can be any type of communication terminal or relay for uplink transmission, without limitation. In some embodiments, the terminal device can be any terminal device in the NTN system, such as a UE. In some embodiments, the terminal device can be any terminal device in the NB-IoT system, such as an electricity meter. In some embodiments, the terminal device can be any communication terminal within the coverage of the network device, such as terminal devices 120a to 120j in FIG1.

[0066] As an example, the terminal device is located within the coverage area of ​​an NTN satellite. For example, the terminal device is an NTN IoT terminal.

[0067] As an example, the terminal device is a communication device in any communication system that sends uplink data to devices on the network side.

[0068] In some embodiments, the terminal device is any one of a plurality of terminal devices. The plurality of terminal devices may be multiple communication terminals communicating with the satellite within an NTN cell. These plurality of terminal devices may belong to a terminal device group, such as a first terminal device group.

[0069] The network device can be any of the network-side communication devices described above. In some embodiments, the network device includes a satellite in an NTN system, and the terminal device can communicate with the network device via the satellite. For example, when a base station is deployed on a satellite, the terminal device can communicate directly with the base station on the satellite. For example, when the satellite acts as a relay, the terminal device can communicate with a network device located on the ground via the satellite. As an embodiment, when the network device includes a satellite, the terminal device can be currently located within the service area of ​​that satellite to perform uplink transmission to the network device via the satellite.

[0070] As an example, the network device can be a GEO satellite, or communicate with the terminal device via a GEO satellite.

[0071] As an example, the network device can be an LEO satellite, or communicate with the terminal device via an LEO satellite.

[0072] As an example, the network device can be a MEO satellite, or communicate with the terminal device via a MEO satellite.

[0073] In some embodiments, the network device may be replaced by a satellite. Communication between the network device and the terminal device is communication between the satellite and the terminal device.

[0074] In some embodiments, multiple terminal devices within the first terminal device group are currently within the coverage area of ​​the same satellite.

[0075] The method shown in Figure 4 includes steps S410 and S420, which are described below.

[0076] In step S410, the terminal device receives the first SSB. Correspondingly, the network device can periodically transmit SSBs via the satellite corresponding to the terminal device. For example, the first SSB is at least one of a plurality of SSBs periodically transmitted by the network device based on the SSB cycle.

[0077] In some embodiments, the first SSB is one or more SSBs. For example, the first SSB is any SSB sent by the network device within an SSB cycle. Alternatively, the first SSB is at least one of a plurality of SSBs sent by the network device within an SSB cycle. Or, the first SSB is at least one of a plurality of SSBs sent by the network device within multiple SSB cycles.

[0078] The SSB period is used by network devices or satellites in the NTN system to periodically transmit SSBs, and also by terminal devices to receive SSBs; it is also called the SSB transmission period. As mentioned earlier, for the problem of large coverage areas, NTN uses beam switching to achieve area coverage. To support beam switching when the satellite transmits SSBs, the SSB period is extended; therefore, the SSB period is also called the SSB extended period.

[0079] In some embodiments, the duration of the SSB cycle can be related to the SSB and CORESET multiplexing modes, or it can be related to the satellite altitude in the NTN system. As an example, the duration of the SSB cycle is positively correlated with the satellite altitude.

[0080] In some embodiments, the first SSB originates from a network device within the NTN. This network device can be a satellite covering the area where the terminal device is located, or a network-side device that provides services to the terminal device via that satellite. For example, when a base station is deployed on the satellite, the first SSB originates directly from the satellite within the NTN that communicates with the terminal device. Alternatively, when the satellite acts as a relay, the first SSB is forwarded to the terminal device by the satellite.

[0081] The first SSB is one of multiple SSBs received by the terminal device. The terminal device can receive SSBs from various communication devices. For example, the terminal device can receive SSBs transmitted by multiple different satellites. Alternatively, the terminal device can receive SSBs transmitted by network devices in a terrestrial network. Furthermore, the terminal device can receive SSBs from other terminal devices through multiple sidelinks.

[0082] In some embodiments, the first SSB can be determined based on measurement information from multiple SSBs. The measurement information includes measurement results from multiple SSBs and / or the identities (IDs) of multiple transmit beams corresponding to the multiple SSBs. These multiple transmit beams can be transmit beams from SSBs originating from different communication devices. As an example, the measurement results of the SSBs can be parameters representing signal strength, such as reference signal received power (RSRP). For instance, a terminal device can combine the signal strength (RSRP, etc.) of the SSB with the beam ID to determine the first SSB for initial random access.

[0083] In some embodiments, multiple SSBs are also used by the terminal device to select a preamble during the random access process. During NTN random access, the terminal device can intelligently select a preamble by utilizing the association information between the SSB and PRACH resources. As an example, the terminal device can prioritize using preamble resources from the optimal beam (the SSB with the strongest signal) to increase the probability of being detected by network devices. Through intelligent PRACH preamble selection strategies on the terminal device side, the efficiency of preamble selection can be improved.

[0084] In some embodiments, multiple SSBs can also be used by the terminal device for cell search and / or cell selection. As mentioned above, in an NTN scenario, the terminal device searches for SSBs over a wider frequency range. The terminal device can determine the frequency interval for SSB scanning based on a first parameter, thereby performing SSB scanning for cell search and / or cell selection based on the first parameter. By configuring the first parameter, the frequency domain locations that the terminal device needs to search can be reduced, the search time can be reduced, thereby reducing the scanning range of the terminal device and accelerating the search process.

[0085] The first parameter may be related to one or more pieces of information that reduce the SSB scan range. For example, the first parameter may include one or more of the following: a global synchronization channel number (GSCN) based on a sparse synchronization raster; a predefined global synchronization channel number; a predefined NTN carrier priority; auxiliary positioning information; and the SSB frequency spacing configured in the NTN system. The GSCN may be a unique identifier for each frequency domain location.

[0086] As one embodiment, the terminal device can perform SSB scanning based on a sparse synchronization grating to identify multiple SSBs for cell search or cell selection. Based on the sparse synchronization grating, the initial cell search / cell selection performed by the terminal device does not depend on any stored data. The terminal device can scan all RF channels within its supported frequency band. This scanning, by following a relatively coarse synchronization grating, minimizes the number of potential carrier frequencies, thereby reducing latency caused by band scanning.

[0087] In the above embodiments, the synchronization grating represents the possible frequency locations of SSBs (Secondary Service Buses) within the wireless network carrier, guiding the terminal device on which frequency points to scan during cell search. A sparse synchronization grating can be a synchronization channel grating that is sparser than existing gratings, reducing the number of candidate GSCN locations within the synchronization grating. Since NTNs employ a wider beam coverage, SSBs do not need to be distributed in dense frequency locations as in terrestrial networks. Therefore, the number of synchronization gratings can be reduced, allowing the terminal device to search only a predefined small number of frequency points, rather than the entire frequency band.

[0088] It should be noted that sparse synchronization gratings can also be called carrier rasters. Taking NR as an example, wireless networks can indicate the possible frequency locations of NR carriers by defining discrete location intervals that allow the existence of NR carrier frequencies. NR carrier rasters are RF-related. For example, for the FR1 band (≤6GHz frequency range), the interval can be 100kHz; for the FR2 band (>6GHz), the interval can be 50kHz.

[0089] As one embodiment, a terminal device can perform SSB scanning based on the GSCN of a sparse synchronization grating to identify multiple SSBs for cell search or cell selection. The GSCN can be implemented by establishing a sparse synchronization grating, which limits the number of frequency domain locations of SSBs that the terminal device needs to examine. For example, each candidate carrier frequency is assigned a GSCN, and the terminal device searches for one or more SSBs at each frequency. The sparse synchronization grating limits the number of frequency domain locations of SSBs that the terminal device needs to examine, reducing the scanning range and accelerating the search process. Based on the sparse synchronization grating, the GSCN of an NTN carrier may be relatively small. The terminal device can scan only the frequency domain location (i.e., the GSCN location) corresponding to the GSCN specified by the stored synchronization grating information, instead of the entire frequency band. In other words, the terminal device can scan SSBs only at specific GSCN locations (rather than the entire frequency band).

[0090] As one example, the terminal device can perform SSB scanning based on predefined GSCNs to identify multiple SSBs for cell search or cell selection. For instance, the terminal device can scan only certain predefined GSCN locations instead of the entire frequency band.

[0091] In the above embodiments, the predefined GSCN may also include GSCN frequency points stored by the terminal device. When the terminal device leaves the RRC connection mode, it can store the GSCN frequency points it previously resided in. After entering the RRC idle state (RRC_IDLE), it first searches for SSBs at the stored GSCN locations, i.e., performs an SSB scan. If the search fails, it can fall back to a full-band scan.

[0092] As one example, a terminal device can perform SSB scanning based on predefined NTN carrier priorities to identify multiple SSBs for cell search or cell selection. The NTN system can support multiple NTN carrier frequency bands and configure priority ordering for multiple NTN carriers. The terminal device can prioritize scanning higher-priority NTN carriers. For example, the network device can provide the NTN carrier priority ordering in the RRC release message, allowing the terminal device to scan NTN carriers according to the priority order. Prioritization reduces the number of GSCN frequency domain locations that the terminal device needs to scan, shortening the initial search time.

[0093] As one example, the terminal device can perform SSB scanning based on auxiliary positioning information to identify multiple SSBs for cell search or cell selection. Auxiliary positioning information can be Global Navigation Satellite System (GNSS) positioning information, such as positioning information determined by the Global Positioning System (GPS) or BeiDou system. In NTN scenarios, the terminal device can combine GNSS positioning information to infer its NTN beam area, thereby reducing the search range. As an example, the network device can broadcast GNSS reference information, and the terminal device can infer the possible GSCN corresponding frequency domain location in the NTN cell based on the GNSS location and prioritize scanning these frequency bands.

[0094] As one example, the terminal device can perform SSB scanning based on the SSB frequency spacing configured in the NTN system to identify multiple SSBs for cell search or cell selection. The NTN system can employ a sparser SSB frequency distribution. For example, the current default SSB frequency spacing for NR is 1.44MHz (FR1) or 17.28MHz (FR2). For NTN, this can be adjusted to a larger spacing, such as 3MHz or 20MHz, to reduce the number of search locations. By reducing the number of frequencies the terminal device needs to search, search time can be reduced.

[0095] As one example, the terminal device can perform SSB scanning based on different SSB scanning strategies to identify multiple SSBs for cell search or cell selection. In other words, the terminal device can dynamically adjust its SSB scanning strategy during SSB scanning. For example, the terminal device can first quickly scan multiple frequencies and then return to the frequencies where SSBs may exist for a more refined search. Alternatively, the terminal device can first scan multiple GSCN locations with a larger step size (e.g., 5MHz intervals) and then return to the location with stronger signal for a second, more precise scan. This method reduces the waiting time of the terminal device on frequencies with no signal, accelerating the search process.

[0096] As one example, the method by which the terminal device performs SSB scanning is related to satellite altitude. For instance, in a GEO scenario, sparse synchronization gratings and relaxed NTN carrier gratings can be used to reduce the number of frequencies the terminal device needs to scan. Similarly, in a LEO scenario, a faster SSB frequency search mode and frequency offset compensation can be used to accelerate the terminal device's search process.

[0097] In some embodiments, the first SSB is one of multiple SSBs transmitted by the network device. These multiple SSBs are transmitted via multiple beams, which are scheduled using time division multiplexing (TDM). In TDM scheduling, multiple beams are not active simultaneously. That is, the network device does not transmit all beams at the same time. When a beam is active, signal transmission and reception can occur within its coverage area; when a beam is inactive, transmission and reception are not possible. Therefore, beam scheduling based on TDM can also be understood as area coverage based on beam switching. The multiple beams transmitting multiple SSBs can be multiple transmission beams of a satellite. Multiple transmission beams can cover different areas at different times through beam switching.

[0098] In some embodiments, the first SSB can be transmitted via the network device's common channel. In an NTN, both the SSB and the system information block (SIB) can be transmitted via the NTN's broadcast channel. Satellites can use wider beam coverage to transmit the DL common channel to achieve potential downlink enhancement. In particular, GEO and LEO satellites, due to their wide coverage, can ensure that terminal devices in a larger area can receive these broadcast messages, reducing blind spots.

[0099] As an example, the wider beamwidth of the common channel can be relative to the beamwidth of the dedicated channel. In NTN, the DL / UL dedicated channels (including PRACH) can be transmitted using narrower beamwidth coverage. That is, the beamwidth coverage of the first type of beamwidth corresponding to the common channel is greater than the beamwidth coverage of the second type of beamwidth corresponding to the dedicated channel.

[0100] In the above embodiments, the first type of beam and the second type of beam are the satellite's transmission beams. The first type of beam can be a transmission beam with a beamwidth greater than a set threshold, and the second type of beam can be a transmission beam with a beamwidth less than or equal to the set threshold.

[0101] In the above embodiments, the beam coverage of the first type of beam or the second type of beam can be equivalent to the size of the coverage area or the load of the coverage area. For example, the area of ​​the coverage area of ​​the first type of beam used to transmit a common channel can be larger than the area of ​​the coverage area of ​​the second type of beam used to transmit a dedicated channel. As another example, the number of terminal devices in the coverage area of ​​the first type of beam used to transmit a common channel is greater than the number of terminal devices in the coverage area of ​​the second type of beam used to transmit a dedicated channel.

[0102] As an example, the first SSB is transmitted based on the SSB extended period, which can achieve beam hopping of the common signal / channel. The common signal / channel can be used to transmit SSB and SIB1 / SIB19.

[0103] In some embodiments, after receiving the first SSB, the terminal device can predict the next SSB beam transmission time based on accompanying information and send PRACH in advance at a suitable RO. Accompanying information includes, for example, the satellite's orbital position, SSB period, and current tracking area code (TAC). As an example, the network device can introduce a "next transmission period time stamp" field into the SSB or SIB. The terminal device can calculate the expected arrival time based on its position and predicted time, and pre-initiate access according to the advance "predicted access window" and relevant trajectory provided in the relevant configuration (e.g., RACH configuration), thereby reducing PRACH waiting delays and avoiding missing the corresponding window.

[0104] As one embodiment, the first SSB is transmitted within the first SSB cycle. The first SSB also includes a timestamp for the second SSB cycle, which is used to transmit the second SSB. This timestamp serves as the timestamp for the next transmission cycle. This timestamp can be used to determine the arrival time of the second SSB, and the first RO arrives earlier than the arrival time of the second SSB. In other words, the terminal device will transmit the first PRACH in advance.

[0105] In step S420, the terminal device transmits a first random access channel on the first RO corresponding to the first transmit beam. The first random access channel can be replaced by a first PRACH. For simplicity, the following explanation uses the first PRACH as an example.

[0106] During the random access process, the first PRACH is message 1 (Msg1). The first PRACH is used by the terminal device to send a preamble. After the terminal device determines the first SSB, the preamble sent by the first PRACH is one of the preambles in the set corresponding to the first SSB.

[0107] In some embodiments, the transmit power of the first PRACH can be determined in various ways. As one example, the terminal device can fully utilize the channel state information (CSI) obtained from the downlink to adjust the transmit power of the first PRACH to reduce the access failure rate. As another example, the NTN system can employ an open-loop PRACH power control mechanism, whereby the terminal device can set the transmit power of the preamble sequence (preamble code) based on the target received power of the satellite broadcast and the measured path loss, ensuring that it does not exceed its own power amplifier limit. For example, if the SSB indication signal is weak (meaning high path loss), the terminal device can increase the transmit power to near the target value when initially transmitting message 1 to increase the chance of a successful access. Conversely, if the CSI indicates a good link condition, the terminal device can appropriately reduce the transmit power while meeting the detection threshold to avoid unnecessary energy waste and interference.

[0108] The transmission of the first PRACH can be triggered in several ways. As one embodiment, the terminal device can dynamically trigger the transmission of the first PRACH based on the first SSB. The terminal device only transmits when the SSB is detected and according to the RO specified by the SSB, which helps avoid blind transmission of the first PRACH and reduces power consumption. As another embodiment, the terminal device can transmit the first PRACH based on an instruction from the network device. That is, the network device can dynamically adjust the triggering timing of the first PRACH to adapt to different beam coverage conditions. As another embodiment, the transmission of the first PRACH can be determined based on the transmission of the UL beam. This UL beam may include the first transmit beam.

[0109] The terminal device can transmit the first PRACH through the first transmit beam; therefore, the first transmit beam is the uplink beam of the terminal device. After the terminal device transmits the first PRACH through the first transmit beam, the network device will listen for the first PRACH.

[0110] In some embodiments, the first transmit beam is associated with the index of a first SSB. That is, the network device can perform UL beam tracking based on the SSB index, i.e., determine the corresponding PRACH transmit beam, i.e., the first transmit beam, based on the index of the first SSB. For example, the network device can record which SSB index the terminal device detects and estimate the direction of the UL beam transmitted by the terminal device based on that SSB. The network device can listen to the corresponding beam only at the expected RO, reducing UL resource waste.

[0111] The first transmit beam corresponds to the first receive beam of the network device; they can be understood as a beam pair. When the terminal device transmits the first PRACH through the first transmit beam, the network device receives the first PRACH through the first receive beam. Since the first receive beam originates from a satellite, its coverage area is relatively large. Due to varying coverage areas, the transmit beam and receive beam of a PRACH may not correspond one-to-one. When the first transmit beam is a single beam transmitted by the terminal device, the first receive beam is either a Type I beam or a Type II beam used by the network device for PRACH monitoring. When the first transmit beam consists of multiple beams transmitted by the terminal device, the first receive beam is either a Type I beam or multiple Type II beams used by the network device for PRACH monitoring.

[0112] It should be noted that when a network device acts as a transmitter, its receiving beam can also be used as a transmitting beam to send an SSB. For example, a network device can transmit a first SSB using a second transmitting beam. The coverage area of ​​the second transmitting beam can be the same as that of the first receiving beam, so that the terminal device can send a first PRACH after receiving the first SSB.

[0113] In some embodiments, the first receive beam belongs to multiple receive beams used by the network device to receive random access channels. These multiple receive beams are scheduled based on TDM (Transmission Directives). Both the receive and transmit beams of the network device can be beamformed based on TDM scheduling. For example, the first receive beam may be at least one of multiple receive beams used by the network device within one SSB (Security Service Bus) cycle or one SSB extension cycle. These multiple receive beams can monitor PRACH messages transmitted by all terminal devices within the coverage area through beam switching.

[0114] The network device listens for the first PRACH within a first time period. This first time period can be understood as the PRACH listening window. The first receive beam is used to determine this first time period. When the first receive beam is one of multiple receive beams based on time-division multiplexing scheduling, the activation time of the first receive beam includes the first time period. Therefore, the network device can set a "UL listening window," i.e., the first time period, for each receive beam. The UL beam (first transmit beam) sent by the terminal device can correspond to the first time period. For example, for receive beam A, the network device activates the UL beam in [t0, t0+10ms] to listen for PRACH within the coverage area of ​​beam A; for receive beam B, it activates the UL beam in [t1, t1+10ms] to listen for PRACH within the coverage area of ​​beam B. Correspondingly, the terminal device sends a PRACH for receive beam A within [t0, t0+10ms], ensuring that the PRACH sent by the terminal device will arrive only when the network device is listening for that receive beam. Therefore, it can be seen that during the time period not allocated as a PRACH listening window, the terminal device does not send PRACH.

[0115] As an example, the duration of the first time period is less than or equal to the activation time of the first receiving beam.

[0116] As an example, the duration of the first time period can be one of one or more subframes, one or more frames, or one or more time slots. For example, in a scenario with an SSB period of 160ms, each receive beam only opens PRACH listening within multiple subframes. Alternatively, the duration of the first time period can include multiple random access time slots.

[0117] As an example, the duration of the first time period can be dynamically extended to ensure that network devices have more time to detect PRACH, thereby improving the access success rate of terminal devices. For example, the duration of the first time period can be determined based on the SSB cycle, the duration of which is related to satellite altitude. That is, the duration of the first time period can be dynamically adjusted based on the SSB cycle. For example, for GEO scenarios, the duration of the first time period can be extended to 500ms to accommodate longer SSB cycles. Similarly, for LEO scenarios, network devices also need to support longer PRACH listening windows (e.g., the duration of the first time period is 2-3 SSB cycles) to ensure that PRACH is not lost due to beam changes. Correspondingly, network devices can also configure multiple ROs for terminal devices to reduce the waiting time of terminal devices.

[0118] In some embodiments, the first time period may correspond to one or more ROs. The one or more ROs corresponding to the first time period are ROs that the network device can listen to within the first time period. Based on the configuration of the first time period, the terminal device only sends the PRACH preamble on the ROs that the network device explicitly listens to, in order to reduce invalid random access channels within the beam period that the network device cannot listen to or does not listen to.

[0119] As one example, the first receiving beam is used by the network device to monitor PRACH, and the first receiving beam can correspond to multiple ROs. One or more ROs corresponding to the first time period belong to the multiple ROs corresponding to the first receiving beam.

[0120] As an example, one or more ROs corresponding to the first time period can be used by multiple terminal devices to send PRACH.

[0121] In some embodiments, multiple receive beams correspond to multiple transmit beams, and the multiple transmit beams include a first transmit beam, which originate from multiple terminal devices. Each transmit beam corresponds to at least one RO (Redirect Entity), and the at least one RO is determined based on the activation time of the receive beam corresponding to that transmit beam. For example, under a large SSB (Secondary Service Bus) cycle, network devices can set priority ROs / non-priority ROs for different transmit beams and different time slots. If transmit beam X is not monitored by the network device for a certain period in the future, the receive beam corresponding to transmit beam X will not be activated, and the RO corresponding to transmit beam X will also be turned off (the terminal device does not send PRACH). If transmit beam Y is the currently active beam, the corresponding receive beam needs to be activated, and its corresponding RO remains open (the terminal device sends PRACH).

[0122] As an example, when NTN implements PRACH monitoring within its coverage area based on different receive beams, the network device can allocate an independent set of ROs for each receive beam. This ensures that regardless of which receive beam a terminal device is covered by, there are sufficient ROs for the terminal device to perform random access via the transmit beam. This method avoids access difficulties in some areas caused by using a uniform configuration when there are significant differences in receive beam coverage.

[0123] In the above embodiments, the network device can dynamically adjust the allocation of ROs. The number of allocated ROs is positively correlated with the duration of the first time period. The number of ROs corresponding to each receive beam can be determined based on the historical load and / or current load within the coverage area of ​​that receive beam. For the first receive beam, the number of multiple ROs corresponding to the first receive beam can be determined based on the historical access load and / or current access load within the coverage area of ​​the first receive beam. Each receive beam is used to listen to the uplink beam of the terminal device. Through this adaptive uplink beam listening management, even in the event of beam switching, the network device can still efficiently capture the PRACH preamble signal while minimizing the idle power consumption of the antenna receive link.

[0124] As one implementation, the first receiving beam corresponds to multiple Remote Access Sockets (ROs), the number of which is determined based on the current access load within the coverage area of ​​the first receiving beam. In other words, network devices can flexibly increase or decrease the RO frequency corresponding to a beam based on changes in the access demands of terminal devices under different receiving beams. For example, for coverage beams in areas with dense user activity, the corresponding random access time slots can be increased; for coverage beams in areas with infrequent access requests, ineffective listening overhead can be reduced. Through this dynamic RO scheduling, the PRACH listening capability on the network device side can be optimized. Network devices can concentrate limited uplink listening resources on the currently active receiving beam, improving detection efficiency while reducing unnecessary power consumption.

[0125] As another implementation, historical access load can include historical PRACH request distribution. Network devices can also dynamically adjust the listening priority and PRACH listening window duration for each beam based on historical access load and current network load. For example, a longer listening window can be reserved for a specific receiving beam during busy periods, while the listening interval can be extended during idle periods to save energy.

[0126] The first transmit beam corresponding to the first RO can be understood as the terminal device transmitting the first transmit beam on the first RO or within the first RO window to which the first RO belongs. The first transmit beam can be one or more beams transmitted by the terminal device. For example, when the first RO is a single RO, the first transmit beam is an uplink beam transmitted by the terminal device on that single RO. Similarly, when the first RO is multiple ROs, the first transmit beam is a collection of multiple uplink beams transmitted by the terminal device on those multiple ROs.

[0127] As an example, the first RO corresponding to the first transmit beam is at least one of the plurality of ROs corresponding to the first receive beam.

[0128] The first RO can be one or more ROs. For example, the first RO can be any one of the multiple ROs corresponding to the first transmit beam. Alternatively, the first RO can be at least one of the multiple ROs corresponding to the first transmit beam. Network devices do not need to continuously monitor all ROs. For example, network devices can pre-configure (or dynamically update) which ROs are suitable for the current or subsequent receive beams and inform the terminal devices. The terminal devices only attempt random access on these ROs to improve the success rate.

[0129] In some embodiments, the first transmit beam corresponds to at least one RO, and the first RO is one or more ROs with the highest priority among the at least one RO. That is, the multiple ROs configured by the network device are prioritized. The network device can determine the priority of different ROs based on artificial intelligence algorithms and inform the terminal device. The terminal device can preferentially select one or more ROs with the highest priority among the at least one ROs corresponding to the first transmit beam to transmit the first PRACH.

[0130] As an example, to ensure that the terminal device prioritizes sending the preamble on ROs that the network device can detect, the network device can define a higher-priority RO among the multiple ROs associated with the SSB. The terminal device can preferentially select these ROs to send the preamble, thereby increasing the probability that the first PRACH will be detected or monitored by the network device.

[0131] For example, the priority of ROs can include only two levels: priority ROs and non-priority ROs. The RO with the highest priority is the priority RO.

[0132] In some embodiments, the first transmit beam corresponds to at least one Remotely Operated (RO), and the first RO is one or more ROs currently active among the at least one RO. The network device can dynamically enable / disable one or more ROs based on satellite beam hopping. The first RO that the terminal device transmits the first PRACH for is one or more currently active ROs. For example, the network device's scheduling module can activate ROs only during the coverage time of the received beam based on ephemeris and time zone.

[0133] The first time period (PRACH listening window) can correspond to the first RO window, which includes the first RO. The RO window can be related to the RO period. When configuring network devices, the RO window and PRACH listening window can be configured appropriately based on satellite altitude to ensure that PRACH messages sent by terminal devices within the RO window can be listened to during the first time period.

[0134] As an example, in an NTN beam-hopping scenario, the PRACH transmit window (RO window) needs to be aligned with the transmission time of the receive beam. Since satellites cannot transmit all receive beams simultaneously, periodic beam-hopping is required to cover each area. To ensure random access is unaffected by beam-hopping, network devices can allocate an appropriate RO window for each beam during its active period. For example, within a beam-hopping cycle (let's assume cycle T), the network device schedules at least one corresponding RO for each receive beam. When a receive beam covers an area, terminal devices within that area can attempt random access via the device's beam on that RO. For instance, the network device can ensure at least one random access opportunity every 160ms in any area based on the beam-hopping rate.

[0135] In some embodiments, the first RO window may include one or more ROs associated with the first SSB. In NTN, due to the long SSB period, multiple beams may simultaneously cover different areas (e.g., in FR2 scenarios), leading to RO conflicts. This is because network devices can only listen to a limited number of uplink beams, and ROs are typically configured starting from radio frame 0. Multiple uplink beams may share the same PRACH resource (RO), causing PRACH failures or conflicts. Furthermore, even if the network device uses TDM to transmit SSBs, the default timing of the ROs may not correctly match the SSB locations, thus affecting the PRACH success rate of the terminal device.

[0136] As an example, the first SSB may indicate multiple ROs, and the terminal device can match a time window that is less than or equal to the network setting according to its own capabilities. The terminal device can send the first PRACH on the ROs within this time window.

[0137] In another embodiment, the first SSB is associated with a first RO window. That is, the first SSB can directly indicate a first RO window that includes multiple ROs. The terminal device can send a first PRACH on at least one RO within the first RO window.

[0138] As an example, the first RO window can be determined based on the index of the first SSB and / or the configuration period of the RO. This configuration period can be an SSB period or a defined logical period. For example, when NTN supports cross-period SSB and RO mapping, multiple SSB periods can be virtually merged into a single logical period. The logical period is defined as N × SSB period, where N is a positive integer. When the SSB period is 160ms and N is 2, the logical period is 320ms. When the RO configuration is uniformly arranged across logical periods, the terminal device can locate the RO window using the SSB index and the logical period number. Based on the definition of the logical period, a larger mapping space can be provided.

[0139] As an example, the first RO window is associated with the index of the first SSB. The network device can configure the RO window associated with each SSB for the terminal device; that is, different RO windows can be associated with different SSBs. For example, the SSB index corresponds to the RO window, i.e., SSB-0 corresponds to RO window A, and SSB-1 corresponds to RO window B. Only ROs within the RO window corresponding to the SSB detected by the terminal device are considered valid ROs. Based on this configuration, it can be ensured that the terminal device only sends preambles within the RO window associated with the SSB, avoiding contention.

[0140] In the above embodiments, the time offset of the first RO window relative to the first SSB can be related to the index of the first SSB. The network device can specify the RO window length and the time offset relative to the SSB index to the terminal device to form the RO window configuration. For example, the network device can specify the duration of the first RO window and the time offset corresponding to the first SSB index to the terminal device.

[0141] As one example, the offset corresponding to the first RO window is related to the index of the first transmit beam. This offset, also known as the RO offset, helps avoid RO resource overlap. For instance, an offset is added to each transmit beam (RO beam) in the RO configuration, such as transmit beam 1 = 0ms, transmit beam 2 = 10ms, and transmit beam 3 = 20ms. By introducing the offset, the ROs of each transmit beam can be staggered. Network devices can then listen to the ROs in different beams in turn. The RO offset improves configuration flexibility, thereby avoiding unnecessary overlap of ROs from different beams. Without the RO offset configuration, avoiding RO overlap from different beams could be very difficult.

[0142] As an example, the first RO window can be configured based on a first switching mechanism. The first switching mechanism can be used to indicate one or more switching cycles related to the wake-up of the terminal device, in order to determine whether the terminal device has been woken up. Therefore, the first switching mechanism can be a mechanism similar to discontinuous reception (DRX) implemented according to PRACH gating. For example, the terminal device can wake up within an appropriate switching cycle, and if it fails to access the system within the configured random access slot, it can continue to sleep. If the terminal device fails to access the system in a random access slot, it can also retry in the next appropriate slot according to rules pre-configured in the RRC, instead of blindly sending a preamble in every subframe.

[0143] As one embodiment, the first RO or first RO window can be configured after the SSB is transmitted. For example, the network device can schedule the first RO immediately following the broadcast time of the first SSB to utilize the effective time slot after the SSB transmission to improve the probability of successful access. If multiple SSB beams (multiple SSBs) overlap in the coverage area, the terminal device can select an appropriate RO (e.g., the RO corresponding to the strongest SSB) based on the received SSB strength and configuration to improve the access success rate.

[0144] As an example, the system frame number corresponding to the first RO can be greater than 0. The configuration frame number of the first RO can start from a radio frame with a frame number other than 0. As mentioned above, the RO starts from a radio frame with a system frame number of 0 by default. In the NTN system, the SSB may use TDM for transmission, allowing the RO to start from a frame other than radio frame 0, which can more flexibly indicate the starting position of the RO.

[0145] In the above embodiments, the time-domain position of the first RO is determined based on the transmission time of the first SSB and / or the RO offset. This RO offset can represent the offset between the first RO and the first SSB. Therefore, the network device can support radio frame alignment between RO and SSB transmissions; that is, different SSBs correspond to different RO start frames. For example, if SSB beam 1 appears in frame 10, the corresponding RO is configured starting from frame 10; if SSB beam 2 appears in frame 20, the corresponding RO is configured starting from frame 20. By setting different RO start frames for different SSBs, it can be ensured that the RO closely follows the SSB.

[0146] The above section introduced several embodiments for determining the RO window based on SSB. These embodiments can be combined with each other. For example, in GEO scenarios, using SSB-associated RO windows and enhanced DRX control for PRACH transmission for random access can avoid excessive network device listening load and ensure that terminal devices only send preambles on valid ROs. As another example, in LEO / MEO scenarios, RO offsets can be used to stagger ROs and avoid PRACH resource conflicts. Furthermore, a method can be used where the RO starts from frames other than radio frame 0 to match SSB transmissions based on TDM.

[0147] In some embodiments, the first RO window can be determined based on the indication of the network device to determine that the first PRACH arrives within the time slot being listened to by the network device. The indication information of the first RO window may be carried in one or more of the following: downlink control information (DCI) 1_0; RRC signaling; medium access control (MAC) control element (CE), i.e., MAC-CE; SIB; first SSB.

[0148] As an example, for PRACH sniffing triggered by downlink control information, the network device can indicate the first PRACH transmission window, i.e., the first RO window, to the terminal device via DCI or RRC signaling. For example, the network device can indicate the time window for the terminal device to send the PRACH via DCI 1_0.

[0149] As an example, the available RO window, i.e., the first RO window, can be clearly defined between network devices and terminal devices through signaling such as RRC / SIB / MAC-CE. For example, network devices can add an indicator field for dynamic RO windows in RRC or MAC.

[0150] As one embodiment, the network device can announce the first RO window when broadcasting the first SSB, and configure a beam-aware table (Beam-PrachMap) in the SIB to identify the start time and duration of the valid RO window corresponding to each received beam. When the terminal device senses the first SSB, the first SSB also includes the identifier of the first received beam and / or the offset of the first RO window. That is, when the terminal device senses the SSB, it can obtain the beam ID and the offset value of the corresponding RO window.

[0151] In some embodiments, when the terminal device is a low-power device, it can be woken up before the first RO according to relevant configurations. For example, according to RRC configuration, the terminal device can briefly wake up and send PRACH before a specified RO, and then quickly enter low-power mode.

[0152] The preceding text, with reference to Figure 4, described a method for a terminal device to perform cell search and random access based on the received first SSB. During this random access process, the terminal device can determine the first RO (Redirection) for transmitting the first PRACH based on the first SSB. The following text, with reference to Figure 5, provides an exemplary description of the method by which the terminal device determines the RO based on the SSB.

[0153] Referring to Figure 5, multiple SSB#0s are periodically transmitted based on TDM mode. Within an SSB periodicity, SSB#0s with different shades represent SSB#0s transmitted via different beams. This SSB period can be the extended SSB period in NTN. As shown in Figure 5, the RO corresponding to a beam or SSB#0 can be determined based on the SSB#0s transmitted via different beams and the RO offset. When the first SSB is any of the SSB#0s, the first RO is its corresponding RO.

[0154] As shown in Figure 5, when different SSBs need to be transmitted in TDM mode within the extended SSB period of different beam coverage, the start of the RO may need to be closer to the SSB position of the corresponding beam coverage. RO offset-based configuration allows each RO to be closer to its corresponding SSB, thus providing better configuration flexibility to achieve RO-SSB correspondence.

[0155] The method embodiments of this application have been described in detail above with reference to Figures 1 to 5. The apparatus embodiments of this application are described in detail below with reference to Figures 6 to 8. It should be understood that the descriptions of the apparatus embodiments correspond to the descriptions of the method embodiments; therefore, any parts not described in detail can be referred to the preceding method embodiments.

[0156] Figure 6 is a schematic block diagram of a wireless communication device according to an embodiment of this application. The device 600 can be any of the terminal devices described above. The device 600 shown in Figure 6 includes a receiving unit 610 and a transmitting unit 620.

[0157] The receiving unit 610 can be used to receive the first SSB.

[0158] The transmitting unit 620 can be used to transmit a first random access channel on a first RO corresponding to a first transmit beam; wherein, the first SSB comes from a network device in the NTN, the first transmit beam corresponds to a first receive beam of the network device, the first receive beam is used by the network device to determine a first time period, and the first time period is used by the network device to listen to the first random access channel through the first receive beam.

[0159] Optionally, the first SSB is one of a plurality of SSBs sent by the network device, the plurality of SSBs being sent through a plurality of beams, and the plurality of beams being scheduled based on time division multiplexing.

[0160] Optionally, the first receiving beam corresponds to a plurality of ROs, the first RO being at least one of the plurality of ROs, and the number of the plurality of ROs being determined based on the historical access load and / or current access load within the coverage area of ​​the first receiving beam.

[0161] Optionally, the first transmit beam corresponds to at least one RO, the first RO being one or more ROs with the highest priority among the at least one ROs, and / or, the first RO being one or more ROs currently active among the at least one ROs.

[0162] Optionally, the first time period corresponds to a first RO window including the first RO, and the indication information of the first RO window is carried in one or more of the following: DCI 1_0; RRC signaling; MAC-CE; SIB; the first SSB.

[0163] Optionally, the first RO window is associated with the index of the first SSB, or the offset corresponding to the first RO window is associated with the index of the first transmit beam.

[0164] Optionally, when the terminal device senses the first SSB, the first SSB further includes the identifier of the first receiving beam and / or the offset of the first RO window.

[0165] Optionally, the first RO window is configured based on a first switch mechanism, which is used to determine whether the terminal device is woken up.

[0166] Optionally, the time-domain location of the first RO is determined based on the transmission time of the first SSB and / or the RO offset.

[0167] Optionally, the first SSB is transmitted within a first SSB cycle, and the first SSB further includes a time stamp for a second SSB cycle in which a second SSB is transmitted. The time stamp is used to determine the arrival time of the second SSB, and the first RO is earlier than the arrival time of the second SSB.

[0168] Optionally, the duration of the first time period is determined based on the SSB cycle, the duration of which is related to the satellite altitude in the NTN.

[0169] Optionally, the first SSB is transmitted via a common channel, and the beam coverage of the first type of beam corresponding to the common channel is greater than the beam coverage of the second type of beam corresponding to the dedicated channel.

[0170] Optionally, the first SSB is one of a plurality of SSBs received by the terminal device, and the first SSB is determined based on the measurement results of the plurality of SSBs and / or the identifiers of the plurality of transmit beams corresponding to the plurality of SSBs.

[0171] Optionally, the plurality of SSBs are used by the terminal device to perform cell search and / or cell selection based on a first parameter, wherein the first parameter is used to determine the frequency interval of the SSB scan.

[0172] Optionally, the first parameter includes one or more of the following: a global synchronization channel number based on a sparse synchronization grating; a predefined global synchronization channel number; a predefined NTN carrier priority; auxiliary positioning information; and the SSB frequency spacing configured in the NTN system.

[0173] Figure 7 is a schematic block diagram of another device for wireless communication according to an embodiment of this application. This device 700 can be any of the network devices described above. The device 700 shown in Figure 7 includes a transmitting unit 710 and a receiving unit 720.

[0174] The transmitting unit 710 can be used to transmit multiple SSBs, the multiple SSBs including the first SSB received by the terminal device.

[0175] The receiving unit 720 can be used to listen to the first random access channel during a first time period via a first receiving beam; wherein, the network device belongs to NTN, the first receiving beam is used by the network device to determine the first time period, the first receiving beam corresponds to the first transmitting beam of the terminal device, and the first random access channel is transmitted on the first RO corresponding to the first transmitting beam.

[0176] Optionally, the multiple SSBs are transmitted through multiple beams, and the multiple beams are scheduled based on time division multiplexing.

[0177] Optionally, the first receiving beam corresponds to a plurality of ROs, the first RO being at least one of the plurality of ROs, and the number of the plurality of ROs being determined based on the historical access load and / or current access load within the coverage area of ​​the first receiving beam.

[0178] Optionally, the first transmit beam corresponds to at least one RO, the first RO being one or more ROs with the highest priority among the at least one ROs, and / or, the first RO being one or more ROs currently active among the at least one ROs.

[0179] Optionally, the first time period corresponds to a first RO window including the first RO, and the indication information of the first RO window is carried in one or more of the following: DCI 1_0; RRC signaling; MAC-CE; SIB; the first SSB.

[0180] Optionally, the first RO window is associated with the index of the first SSB, or the offset corresponding to the first RO window is associated with the index of the first transmit beam.

[0181] Optionally, when the terminal device senses the first SSB, the first SSB further includes the identifier of the first receiving beam and / or the offset of the first RO window.

[0182] Optionally, the first RO window is configured based on a first switch mechanism, which is used to determine whether the terminal device is woken up.

[0183] Optionally, the time-domain location of the first RO is determined based on the transmission time of the first SSB and / or the RO offset.

[0184] Optionally, the first SSB is transmitted within a first SSB cycle, and the first SSB further includes a time stamp for a second SSB cycle in which a second SSB is transmitted. The time stamp is used to determine the arrival time of the second SSB, and the first RO is earlier than the arrival time of the second SSB.

[0185] Optionally, the duration of the first time period is determined based on the SSB cycle, the duration of which is related to the satellite altitude in the NTN.

[0186] Optionally, the first SSB is transmitted via a common channel, and the beam coverage of the first type of beam corresponding to the common channel is greater than the beam coverage of the second type of beam corresponding to the dedicated channel.

[0187] Optionally, the first SSB is one of a plurality of SSBs received by the terminal device, and the first SSB is determined based on the measurement results of the plurality of SSBs and / or the identifiers of the plurality of transmit beams corresponding to the plurality of SSBs.

[0188] Optionally, the plurality of SSBs are used by the terminal device to perform cell search and / or cell selection based on a first parameter, wherein the first parameter is used to determine the frequency interval of the SSB scan.

[0189] Optionally, the first parameter includes one or more of the following: a global synchronization channel number based on a sparse synchronization grating; a predefined global synchronization channel number; a predefined NTN carrier priority; auxiliary positioning information; and the SSB frequency spacing configured in the NTN system.

[0190] Figure 8 is a schematic diagram of the structure of a communication device according to an embodiment of this application. The dashed lines in Figure 8 indicate that the unit or module is optional. This device 800 can be used to implement the methods described in the above method embodiments. Device 800 can be a chip, a terminal device, or a network device.

[0191] The apparatus 800 may include one or more processors 810. The processor 810 may support the apparatus 800 in implementing the methods described in the preceding method embodiments. The processor 810 may be a general-purpose processor or a special-purpose processor. For example, the processor may be a central processing unit (CPU). Alternatively, the processor may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0192] The apparatus 800 may further include one or more memories 820. The memories 820 store a program that can be executed by the processor 810, causing the processor 810 to perform the methods described in the preceding method embodiments. The memories 820 may be independent of the processor 810 or integrated within the processor 810.

[0193] The device 800 may also include a transceiver 830. The processor 810 can communicate with other devices or chips via the transceiver 830. For example, the processor 810 can send and receive data with other devices or chips via the transceiver 830.

[0194] This application also provides a computer-readable storage medium for storing a program. This computer-readable storage medium can be applied to a terminal device or network device provided in this application embodiment, and the program causes a computer to execute the methods performed by the terminal device or network device in the various embodiments of this application.

[0195] The computer-readable storage medium can be any available medium that a computer can read, or a data storage device such as a server or data center that integrates one or more available media. The available medium can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital video discs, DVDs), or semiconductor media (e.g., solid-state disks, SSDs), etc.

[0196] This application also provides a computer program product. The computer program product includes a program. This computer program product can be applied to a terminal device or network device provided in the embodiments of this application, and the program causes a computer to execute the methods performed by the terminal device or network device in the various embodiments of this application.

[0197] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0198] This application also provides a computer program. This computer program can be applied to a terminal device or network device provided in this application, and the computer program causes the computer to execute the methods performed by the terminal or network device in various embodiments of this application.

[0199] In this application, the terms "system" and "network" are used interchangeably. Furthermore, the terminology used in this application is only for explaining specific embodiments of the application and is not intended to limit the application. The terms "first," "second," "third," and "fourth," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. In addition, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0200] In the embodiments of this application, the term "instruction" can be a direct instruction, an indirect instruction, or an indication of a relationship. For example, A instructing B can mean that A directly instructs B, such as B being able to obtain information through A; it can also mean that A indirectly instructs B, such as A instructing C, so B can obtain information through C; or it can mean that there is a relationship between A and B.

[0201] In the embodiments of this application, the term "correspondence" may indicate a direct or indirect correspondence between two things, or an association between two things, or a relationship such as instruction and being instructed, configuration and being configured.

[0202] In the embodiments of this application, "predefined" or "preconfigured" can be implemented by pre-storing corresponding codes, tables, or other means that can be used to indicate relevant information in the device (e.g., including terminal devices and network devices). This application does not limit the specific implementation method. For example, predefined can refer to what is defined in the protocol.

[0203] In the embodiments of this application, determining B based on A or based on A does not mean that B is determined solely based on A; B can also be determined based on A and / or other information.

[0204] In the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0205] In the embodiments of this application, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0206] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0207] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0208] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0209] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for wireless communication, comprising: include: The terminal device receives the first synchronization signal block (SSB); The terminal device transmits the first random access channel on the first random access channel timing RO corresponding to the first transmission beam; Wherein, the first SSB comes from a network device in a non-terrestrial network (NTN), the first transmit beam corresponds to the first receive beam of the network device, the first receive beam is used by the network device to determine a first time period, and the first time period is used by the network device to listen to the first random access channel through the first receive beam.

2. The method of claim 1, wherein, The first SSB is one of a plurality of SSBs sent by the network device. The plurality of SSBs are sent through a plurality of beams, which are scheduled based on time division multiplexing.

3. The method according to claim 1 or 2, characterized in that, The first receiving beam corresponds to multiple access points (ROs), and the first RO is at least one of the multiple ROs. The number of the multiple ROs is determined based on the historical access load and / or current access load within the coverage area of ​​the first receiving beam.

4. The method according to any one of claims 1 to 3, characterized in that, The first transmit beam corresponds to at least one RO, the first RO being one or more ROs with the highest priority among the at least one ROs, and / or, the first RO being one or more ROs currently active among the at least one ROs.

5. The method according to any one of claims 1 to 4, characterized in that, The first time period corresponds to a first RO window including the first RO, and the indication information of the first RO window is carried in one or more of the following: Downlink control information DCI 1_0; Radio Resource Control (RRC) signaling; Media access control MAC-control unit CE; System Information Block (SIB); The first SSB.

6. The method of claim 5, wherein, The first RO window is related to the index of the first SSB, or the offset corresponding to the first RO window is related to the index of the first transmit beam.

7. The method of claim 5, wherein, When the terminal device senses the first SSB, the first SSB also includes the identifier of the first receiving beam and / or the offset of the first RO window.

8. The method of claim 5, wherein, The first RO window is configured based on a first switch mechanism, which is used to determine whether the terminal device is woken up.

9. The method according to any one of claims 1 to 8, characterized in that, The time-domain position of the first RO is determined based on the transmission time of the first SSB and / or the RO offset.

10. The method according to any one of claims 1 to 9, characterized in that, The first SSB is transmitted within a first SSB cycle. The first SSB also includes a time stamp for a second SSB cycle during which a second SSB is transmitted. The time stamp is used to determine the arrival time of the second SSB. The first RO arrives earlier than the arrival time of the second SSB.

11. The method according to any one of claims 1 to 10, characterized in that, The duration of the first time period is determined based on the SSB cycle, the duration of which is related to the satellite altitude in the NTN.

12. The method according to any one of claims 1 to 11, characterized in that, The first SSB is transmitted through a common channel, and the beam coverage of the first type of beam corresponding to the common channel is greater than the beam coverage of the second type of beam corresponding to the dedicated channel.

13. The method according to any one of claims 1 to 12, characterized in that, The first SSB is one of a plurality of SSBs received by the terminal device, and the first SSB is determined based on the measurement results of the plurality of SSBs and / or the identifiers of the plurality of transmit beams corresponding to the plurality of SSBs.

14. The method of claim 13, wherein, The plurality of SSBs are used by the terminal device to perform cell search and / or cell selection based on a first parameter, wherein the first parameter is used to determine the frequency interval of the SSB scan.

15. The method of claim 14, wherein, The first parameter includes one or more of the following: Global synchronization channel number based on sparse synchronization grating; Predefined global synchronization channel number; Predefined NTN carrier priorities; Auxiliary positioning information; SSB frequency spacing configured in NTN systems.

16. A method for wireless communication, comprising: include: The network device sends multiple synchronization signal blocks (SSBs), the multiple SSBs including the first SSB received by the terminal device; The network device listens to the first random access channel during a first time period using the first receiving beam. The network device is a non-terrestrial network (NTN). The first receiving beam is used by the network device to determine the first time period. The first receiving beam corresponds to the first transmitting beam of the terminal device. The first random access channel is transmitted on the first random access channel timing (RO) corresponding to the first transmitting beam.

17. The method of claim 16, wherein, The multiple SSBs are transmitted through multiple beams, and the multiple beams are scheduled based on time division multiplexing.

18. The method of claim 16 or 17, wherein, The first receiving beam corresponds to multiple access points (ROs), and the first RO is at least one of the multiple ROs. The number of the multiple ROs is determined based on the historical access load and / or current access load within the coverage area of ​​the first receiving beam.

19. The method of any one of claims 16-18, wherein, The first transmit beam corresponds to at least one RO, the first RO being one or more ROs with the highest priority among the at least one ROs, and / or, the first RO being one or more ROs currently active among the at least one ROs.

20. The method of any one of claims 16-19, wherein, The first time period corresponds to a first RO window including the first RO, and the indication information of the first RO window is carried in one or more of the following: Downlink control information DCI 1_0; Radio Resource Control (RRC) signaling; Media access control MAC-control unit CE; System Information Block (SIB); The first SSB.

21. The method according to claim 20, characterized in that, The first RO window is related to the index of the first SSB, or the offset corresponding to the first RO window is related to the index of the first transmit beam.

22. The method according to claim 20, characterized in that, When the terminal device senses the first SSB, the first SSB also includes the identifier of the first receiving beam and / or the offset of the first RO window.

23. The method according to claim 20, characterized in that, The first RO window is configured based on a first switch mechanism, which is used to determine whether the terminal device is woken up.

24. The method according to any one of claims 16 to 23, characterized in that, The time-domain position of the first RO is determined based on the transmission time of the first SSB and / or the RO offset.

25. The method according to any one of claims 16 to 24, characterized in that, The first SSB is transmitted within a first SSB cycle. The first SSB also includes a time stamp for a second SSB cycle during which a second SSB is transmitted. The time stamp is used to determine the arrival time of the second SSB. The first RO arrives earlier than the arrival time of the second SSB.

26. The method according to any one of claims 16 to 25, characterized in that, The duration of the first time period is determined based on the SSB cycle, the duration of which is related to the satellite altitude in the NTN.

27. The method according to any one of claims 16 to 26, characterized in that, The first SSB is transmitted through a common channel, and the beam coverage of the first type of beam corresponding to the common channel is greater than the beam coverage of the second type of beam corresponding to the dedicated channel.

28. The method according to any one of claims 16 to 27, characterized in that, The first SSB is one of a plurality of SSBs received by the terminal device, and the first SSB is determined based on the measurement results of the plurality of SSBs and / or the identifiers of the plurality of transmit beams corresponding to the plurality of SSBs.

29. The method according to claim 28, characterized in that, The plurality of SSBs are used by the terminal device to perform cell search and / or cell selection based on a first parameter, wherein the first parameter is used to determine the frequency interval of the SSB scan.

30. The method according to claim 29, characterized in that, The first parameter includes one or more of the following: Global synchronization channel number based on sparse synchronization grating; Predefined global synchronization channel number; Predefined NTN carrier priorities; Auxiliary positioning information; SSB frequency spacing configured in NTN systems.

31. A device for wireless communication, characterized in that, The device is a terminal device, and the device includes: The receiving unit is used to receive the first synchronization signal block (SSB). The transmitting unit is used to transmit the first random access channel on the first random access channel timing RO corresponding to the first transmit beam; Wherein, the first SSB comes from a network device in a non-terrestrial network (NTN), the first transmit beam corresponds to the first receive beam of the network device, the first receive beam is used by the network device to determine a first time period, and the first time period is used by the network device to listen to the first random access channel through the first receive beam.

32. The apparatus according to claim 31, characterized in that, The first SSB is one of a plurality of SSBs sent by the network device. The plurality of SSBs are sent through a plurality of beams, which are scheduled based on time division multiplexing.

33. The apparatus according to claim 31 or 32, characterized in that, The first receiving beam corresponds to multiple access points (ROs), and the first RO is at least one of the multiple ROs. The number of the multiple ROs is determined based on the historical access load and / or current access load within the coverage area of ​​the first receiving beam.

34. The apparatus according to any one of claims 31 to 33, characterized in that, The first transmit beam corresponds to at least one RO, the first RO being one or more ROs with the highest priority among the at least one ROs, and / or, the first RO being one or more ROs currently active among the at least one ROs.

35. The apparatus according to any one of claims 31 to 34, characterized in that, The first time period corresponds to a first RO window including the first RO, and the indication information of the first RO window is carried in one or more of the following: Downlink control information DCI 1_0; Radio Resource Control (RRC) signaling; Media access control MAC-control unit CE; System Information Block (SIB); The first SSB.

36. The apparatus according to claim 35, characterized in that, The first RO window is related to the index of the first SSB, or the offset corresponding to the first RO window is related to the index of the first transmit beam.

37. The apparatus according to claim 35, characterized in that, When the terminal device senses the first SSB, the first SSB also includes the identifier of the first receiving beam and / or the offset of the first RO window.

38. The apparatus according to claim 35, characterized in that, The first RO window is configured based on a first switch mechanism, which is used to determine whether the terminal device is woken up.

39. The apparatus according to any one of claims 31 to 38, characterized in that, The time-domain position of the first RO is determined based on the transmission time of the first SSB and / or the RO offset.

40. The apparatus according to any one of claims 31 to 39, characterized in that, The first SSB is transmitted within a first SSB cycle. The first SSB also includes a time stamp for a second SSB cycle during which a second SSB is transmitted. The time stamp is used to determine the arrival time of the second SSB. The first RO arrives earlier than the arrival time of the second SSB.

41. The apparatus according to any one of claims 31 to 40, characterized in that, The duration of the first time period is determined based on the SSB cycle, the duration of which is related to the satellite altitude in the NTN.

42. The apparatus according to any one of claims 31 to 41, characterized in that, The first SSB is transmitted through a common channel, and the beam coverage of the first type of beam corresponding to the common channel is greater than the beam coverage of the second type of beam corresponding to the dedicated channel.

43. The apparatus according to any one of claims 31 to 42, characterized in that, The first SSB is one of a plurality of SSBs received by the terminal device, and the first SSB is determined based on the measurement results of the plurality of SSBs and / or the identifiers of the plurality of transmit beams corresponding to the plurality of SSBs.

44. The apparatus according to claim 43, characterized in that, The plurality of SSBs are used by the terminal device to perform cell search and / or cell selection based on a first parameter, wherein the first parameter is used to determine the frequency interval of the SSB scan.

45. The apparatus according to claim 44, characterized in that, The first parameter includes one or more of the following: Global synchronization channel number based on sparse synchronization grating; Predefined global synchronization channel number; Predefined NTN carrier priorities; Auxiliary positioning information; SSB frequency spacing configured in NTN systems.

46. ​​An apparatus for wireless communication, characterized in that, The device is a network device, and the device includes: A transmitting unit is used to transmit multiple synchronization signal blocks (SSBs), wherein the multiple SSBs include a first SSB received by the terminal device; A receiving unit is used to monitor a first random access channel during a first time period via a first receiving beam. The network device is a non-terrestrial network (NTN). The first receiving beam is used by the network device to determine the first time period. The first receiving beam corresponds to the first transmitting beam of the terminal device. The first random access channel is transmitted on the first random access channel timing (RO) corresponding to the first transmitting beam.

47. The apparatus according to claim 46, characterized in that, The multiple SSBs are transmitted through multiple beams, and the multiple beams are scheduled based on time division multiplexing.

48. The apparatus according to claim 46 or 47, characterized in that, The first receiving beam corresponds to multiple access points (ROs), and the first RO is at least one of the multiple ROs. The number of the multiple ROs is determined based on the historical access load and / or current access load within the coverage area of ​​the first receiving beam.

49. The apparatus according to any one of claims 46 to 48, characterized in that, The first transmit beam corresponds to at least one RO, the first RO being one or more ROs with the highest priority among the at least one ROs, and / or, the first RO being one or more ROs currently active among the at least one ROs.

50. The apparatus according to any one of claims 46 to 49, characterized in that, The first time period corresponds to a first RO window including the first RO, and the indication information of the first RO window is carried in one or more of the following: Downlink control information DCI 1_0; Radio Resource Control (RRC) signaling; Media access control MAC-control unit CE; System Information Block (SIB); The first SSB.

51. The apparatus according to claim 50, characterized in that, The first RO window is related to the index of the first SSB, or the offset corresponding to the first RO window is related to the index of the first transmit beam.

52. The apparatus according to claim 50, characterized in that, When the terminal device senses the first SSB, the first SSB also includes the identifier of the first receiving beam and / or the offset of the first RO window.

53. The apparatus according to claim 50, characterized in that, The first RO window is configured based on a first switch mechanism, which is used to determine whether the terminal device is woken up.

54. The apparatus according to any one of claims 46 to 53, characterized in that, The time-domain position of the first RO is determined based on the transmission time of the first SSB and / or the RO offset.

55. The apparatus according to any one of claims 46 to 54, characterized in that, The first SSB is transmitted within a first SSB cycle. The first SSB also includes a time stamp for a second SSB cycle during which a second SSB is transmitted. The time stamp is used to determine the arrival time of the second SSB. The first RO arrives earlier than the arrival time of the second SSB.

56. The apparatus according to any one of claims 46 to 55, characterized in that, The duration of the first time period is determined based on the SSB cycle, the duration of which is related to the satellite altitude in the NTN.

57. The apparatus according to any one of claims 46 to 56, characterized in that, The first SSB is transmitted through a common channel, and the beam coverage of the first type of beam corresponding to the common channel is greater than the beam coverage of the second type of beam corresponding to the dedicated channel.

58. The apparatus of any one of claims 46-57, wherein, The first SSB is one of a plurality of SSBs received by the terminal device, and the first SSB is determined based on the measurement results of the plurality of SSBs and / or the identifiers of the plurality of transmit beams corresponding to the plurality of SSBs.

59. The device of claim 58, wherein, The plurality of SSBs are used by the terminal device to perform cell search and / or cell selection based on a first parameter, wherein the first parameter is used to determine the frequency interval of the SSB scan.

60. The device of claim 59, wherein, The first parameter includes one or more of the following: Global synchronization channel number based on sparse synchronization grating; Predefined global synchronization channel number; Predefined NTN carrier priorities; Auxiliary positioning information; SSB frequency spacing configured in NTN systems.

61. A communications device, characterized by It includes a memory and a processor, the memory being used to store a program, and the processor being used to invoke the program in the memory to perform the method as described in any one of claims 1-30.

62. An apparatus, comprising: Includes a processor for calling a program from memory to perform the method as described in any one of claims 1-30.

63. A chip, comprising: Includes a processor for calling a program from memory, causing a device on which the chip is mounted to perform the method as described in any one of claims 1-30.

64. A computer-readable storage medium, characterized in that, It contains a program that causes a computer to perform the method as described in any one of claims 1-30.

65. A computer program product, characterised in that, Includes a program that causes a computer to perform the method as described in any one of claims 1-30.

66. A computer program characterised in that, The computer program causes the computer to perform the method as described in any one of claims 1-30.

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