Method for terminal to access satellite network, terminal device and readable medium

Abstract

The application provides a method for terminal to access a satellite network, a terminal device and a readable medium. The method comprises the following steps: the terminal acquires a history record, which is used to record whether random access is successfully initiated on a beam corresponding to a master information block; when the terminal performs cell search again, one or more master information blocks are acquired, a master information block list is formed according to the power of the physical broadcast channel corresponding to each master information block; the order of each master information block in the master information block list is updated according to the history record, wherein the master information block which exists in the master information block list and successfully initiates random access in the history record is arranged at the first position of the master information block list; according to the updated order, the corresponding system information block is acquired according to the time-frequency information carried by each master information block to judge whether the current beam allows to initiate random access, until the random access is successfully initiated or the master information block list is traversed, and the history record is updated according to the judgment result.

Description

Technical Field

[0001] This application relates primarily to the field of satellite communication technology, and in particular to a method, terminal equipment, and readable medium for a terminal to access a satellite network. Background Technology

[0002] In satellite communication systems, terminal devices need to obtain system messages broadcast by the network side in order to access the satellite network. System messages mainly include the Master Information Block (MIB) and the System Information Block (SIB).

[0003] In satellite networks, terminals face the following technical challenges in acquiring system messages: First, system message acquisition suffers from high latency and power consumption. Because satellite propagation latency is significantly greater than that of terrestrial networks, terminals need to continuously listen and receive throughout the entire broadcast cycle to fully acquire system messages, which is particularly impactful for battery-powered satellite terminals. Second, even after acquiring complete system messages, terminals may still be unable to access the network. Networks typically employ two mechanisms—beam status indication and User Account Control (UAC)—to restrict terminal access. This means that even if a terminal fully acquires the MIB and all SIBs, it may still be denied access due to insufficient signal strength, network access restrictions, failure to meet UAC requirements, or beam reservations by the operator, rendering previous listening and receiving efforts ineffective and consuming power.

[0004] Therefore, there is an urgent need for an access method that can reduce the probability of terminals invalidally obtaining system messages and improve the success rate of terminal network access under satellite networks. Summary of the Invention

[0005] The technical problem to be solved by this application is to provide a method, terminal equipment and readable medium for a terminal to access a satellite network, and to solve the problems of invalid power consumption and access delay caused by the terminal still being unable to access the network after obtaining complete system information.

[0006] To address the aforementioned technical problems, this application provides a method for a terminal to access a satellite network, comprising: the terminal acquiring historical records, the historical records being used to record whether random access has been successfully initiated on the beam corresponding to a master information block; when the terminal performs cell search again, acquiring one or more master information blocks, sorting them according to the power of the physical broadcast channel corresponding to each master information block to form a master information block list; updating the order of each master information block in the master information block list according to the historical records, wherein the master information block that exists in the master information block list and has successfully initiated random access in the historical records is placed at the top of the master information block list; according to the updated order, sequentially acquiring the corresponding system information block based on the time-frequency information carried by each master information block to determine whether the current beam allows random access to be initiated, until random access is successfully initiated or the master information block list has been traversed, and updating the historical records according to the determination result.

[0007] In some embodiments, updating the order of each master information block in the master information block list according to the history further includes placing master information blocks that exist in the master information block list but have never been tried in the history in the second position.

[0008] In some embodiments, updating the order of each master information block in the master information block list according to the historical record further includes placing the master information block that exists in the master information block list but has not successfully initiated random access in the historical record after the second position.

[0009] In some embodiments, updating the order of master information blocks in the master information block list according to the historical record further includes: when the number of master information blocks that were attempted before the last random access was initiated exceeds half of the total number of master information blocks in the current master information block list, and when more than two or more beams under the same satellite number are determined to be not allowed to initiate random access, the master information blocks in the master information block list that are the same as the satellite number and have not successfully initiated random access in the historical record are placed at the end of the master information block list.

[0010] In some embodiments, the operation of placing the main information block with the same satellite number as the satellite in the main information block list at the end of the main information block list that has not successfully initiated random access in the historical record does not apply to main information blocks that have successfully initiated random access in the historical record, and the main information blocks that have successfully initiated random access remain at the top of the main information block list.

[0011] In some embodiments, the method further includes: when the terminal updates the historical records, it synchronously records time information; when the terminal performs a cell search again, if the difference between the current time and the time information corresponding to the most recent successful random access in the historical records exceeds a preset time threshold, then all the historical records are cleared.

[0012] In some embodiments, determining whether the current beam allows random access is determined when all of the following conditions are met: the received signal strength is greater than or equal to the minimum beam threshold configured in the system information block, the network allows access, the unified access control requirements are met, and the beam reservation indication requirements are met.

[0013] In some embodiments, when performing a cell search for the first time, the terminal acquires one or more master information blocks, sorts them according to the power of the physical broadcast channel corresponding to the master information blocks, and forms a master information block list; sequentially acquires the corresponding system information block according to the time and frequency information carried by each master information block, determines whether the current beam allows random access, and generates the historical record based on the determination result.

[0014] To address the aforementioned technical problems, this application provides a terminal device, comprising: a memory storing computer-executable instructions; and a processor for executing the computer-executable instructions stored in the memory, thereby causing the terminal device to perform the method described in this application.

[0015] To address the aforementioned technical problems, this application provides a computer-readable medium including computer program instructions, which, when executed by a processor, cause the processor to perform the methods described in this application.

[0016] Compared with the prior art, this application has the following advantages: The method, terminal device, and readable medium for terminal access to satellite networks disclosed in this application introduce historical records. This allows the terminal to prioritize access to historically successful primary information blocks by considering whether random access has been successfully initiated on the beam corresponding to the primary information block in the historical records when performing cell searches again. After each access attempt, the historical records are updated based on the judgment results, forming a closed-loop learning mechanism. This reduces the number of times the terminal reads invalid system information blocks at the source, lowers access latency and power consumption, and improves the success rate of network access under satellite networks. Attached Figure Description

[0017] The accompanying drawings are included to provide a further understanding of this application. They are incorporated into and constitute a part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of this application.

[0018] Figure 1 This is a flowchart of a method for a terminal to access a satellite network according to an embodiment of this application.

[0019] Figure 2 This is a flowchart of the access process when a terminal performs its first cell search according to an embodiment of this application.

[0020] Figure 3 This is a schematic diagram of a terminal device according to an embodiment of this application. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0022] To facilitate understanding of this application, several terms used in this application will be explained first: Satellite networks refer to networks that use satellites as relay nodes to provide wireless communication services to terminals. Satellite networks can include non-terrestrial networks (NTNs), whose network equipment can be mounted on satellites. Communication coverage is achieved through feeder links between the satellite and ground gateways, and service links between the satellite and terminals. Satellites can be classified according to their orbital altitude into geostationary orbit (GEO) satellites, medium Earth orbit (MEO) satellites, and low Earth orbit (LEO) satellites. Unlike terrestrial cellular networks, satellite networks typically have a larger beam coverage area, and the beam coverage area changes with satellite motion (especially for LEO satellites). Furthermore, the propagation delay of satellite communication is significantly greater than that of terrestrial networks.

[0023] Terminal devices refer to terminal-side devices with wireless communication capabilities, including but not limited to: mobile phones, tablets, laptops, flight vehicles, vehicle user equipment (VUE), shipboard equipment, personal digital assistants (PDAs), ultra-mobile personal computers (UMPCs), mobile internet devices (MIDs), augmented reality (AR) devices, virtual reality (VR) devices, robots, wearable devices, pedestrian user equipment (PUEs), smart home devices, game consoles, personal computers (PCs), ATMs, and self-service machines. Wearable devices include: smartwatches, smart bracelets, smart headphones, smart glasses, smart jewelry, smart wristbands, smart clothing, and non-terrestrial network (NTN) terminals. In this application, terminal equipment specifically refers to terminal equipment that supports satellite communication functions, and which uses the method provided in this application when performing cell selection and access in a satellite network.

[0024] In this application, "beam" refers to the directional coverage area formed by satellite network equipment through phased array antennas or reflector antennas. A satellite can generate multiple beams, each beam corresponding to a beamIdentity. Terminals identify and select beams by detecting synchronization signal blocks (SSBs) and physical broadcast channels (PBSs).

[0025] In satellite communication networks, acquiring complete MIB and SIB system messages consumes significant time and power for terminal devices. However, even after acquiring the complete system messages, the terminal may still be denied access due to insufficient signal strength, network access restrictions, failure to meet Unified Access Control (UAC) requirements, or beam reservations by the operator, rendering previous listening and receiving efforts ineffective. This problem is particularly pronounced in narrowband satellite access networks, where tight link budgets and long propagation delays make repeated invalid acquisition of system messages have a more significant impact on terminal power consumption and user experience.

[0026] To address the aforementioned technical issues, this application introduces beam-level historical access records. When a terminal performs a cell search again, it prioritizes the primary information blocks that have successfully initiated random access in the past, placing them at the top of the primary information block list. After each access attempt, the historical records are updated based on the judgment results, forming a closed-loop learning mechanism of "try-feedback-optimization." This reduces the number of times the terminal reads invalid system information blocks at the source, lowers access latency and power consumption, and improves the success rate of network access under satellite networks.

[0027] Figure 1 This is a flowchart of a method for a terminal to access a satellite network according to an embodiment of this application. Figure 1 As shown, the method 100 for a terminal to access a satellite network includes: Step S1: The terminal obtains the historical records, which are used to record whether a random access has been successfully initiated on the beam corresponding to the main information block.

[0028] In some embodiments, the terminal reads historical records from its storage unit. The historical records may be stored in tabular form, with each record including at least the following fields: beamIdentity, the satellite number to which the beam belongs, whether random access was successfully initiated on that beam, and the timestamp of the most recent attempt. The beamIdentity may include one or a combination of the following: Physical Cell Identifier (PCI), Synchronization Signal Block (SSB) index, frequency point, and a custom beam index within the satellite network.

[0029] It should be noted that if the terminal is being powered on for the first time or its history has been cleared, the terminal will be processed according to the initial network search procedure. Figure 2 As shown, the access process for a terminal during its initial cell search includes: Step S201: Obtain one or more master information blocks, sort them according to the power of the physical broadcast channel corresponding to the master information blocks, and form a master information block list.

[0030] In some embodiments, the terminal detects one or more physical broadcast channels within a receiving window. When multiple physical broadcast channels are detected, the terminal first selects the physical broadcast channel with the strongest power for parsing to obtain one or more master information blocks (MIBs). Then, the terminal sorts the physical broadcast channels corresponding to each MIB from strongest to weakest power to form an initial MIB list.

[0031] It should be noted that during the initial network search, since the terminal has not yet established any historical records, it cannot rearrange the MIB list based on historical experience. Therefore, it sorts the MIBs from strongest to weakest according to signal power, which is the most reasonable order for the terminal to try when there is no prior information.

[0032] Step S202: According to the order of the main information block list, obtain the corresponding system information block in turn based on the time and frequency information carried by each main information block, determine whether the current beam allows random access, and generate historical records based on the determination result.

[0033] The terminal retrieves the corresponding SIB based on the time-frequency information carried by each MIB according to the initial MIB list, and determines whether the current beam allows random access. In some embodiments, determining whether random access is allowed for the current beam requires all of the following conditions to be met: (1) The received signal strength is greater than or equal to the minimum beam threshold configured in the SIB; (2) Network access is permitted (e.g., cellBarred or cellBarredNTN in SIB1 indicates that the cell is not blocked); (3) Meets the unified access control (UAC) requirements (e.g., passes the access restriction check based on uac-BarringInfo in SIB1). (4) Meets the beam reservation indication requirements (e.g., beamReservedForOperatorUse indicates that the beam has not been reserved by the operator).

[0034] If the current beam meets all the above conditions, the terminal initiates random access on that beam and adds a flag indicating successful random access. If the current beam does not meet any of the above conditions, a flag indicating unsuccessful random access is added. The terminal continues to try the next MIB in the MIB list until it successfully initiates random access or traverses the entire MIB list. The terminal stores these records in its storage unit, forming a historical record. These records provide a data basis for the terminal to optimize the access order using historical experience when performing cell searches again.

[0035] Step S2: When the terminal performs cell search again, it acquires one or more master information blocks and sorts them according to the power of the physical broadcast channel corresponding to each master information block to form a master information block list.

[0036] When the terminal performs a cell search again (e.g., when the terminal returns from a coverage blind spot to an area with signal coverage, during a network search after the terminal is powered on, or during a cell reselection triggered by signal loss), the terminal searches according to a predetermined frequency point, search frequency range, and search time domain range. The search time domain range covers the broadcast period and signal duration of the physical broadcast channel.

[0037] The terminal detects one or more physical broadcast channels within the receiving window. When multiple physical broadcast channels are detected, the terminal first selects the physical broadcast channel with the strongest power for parsing to obtain one or more MIBs. Then, the terminal sorts the physical broadcast channels corresponding to each MIB from strongest to weakest power to form an initial MIB list.

[0038] Step S3: Update the order of each main information block in the main information block list according to the historical record, wherein the main information block that exists in the main information block list and has successfully initiated random access in the historical record is placed at the top of the main information block list.

[0039] The terminal updates the order of the MIB list formed in step S2 based on the historical records obtained in step S1. The specific update rules are as follows: (1) First priority: historically successful beams are ranked first.

[0040] MIBs that exist in the MIB list and have successfully initiated random access in the historical records are placed at the top of the MIB list. The principle behind this setting is that a successful random access attempt on a beam indicates that the beam has historically met all access conditions: including adequate signal strength, network access permission, successful UAC check, and the beam not being reserved. Although network configurations may change over time, historical success records are the strongest evidence that the terminal can obtain regarding the beam's past "friendly" behavior. Placing such beams at the top allows the terminal to achieve the highest probability of successful access with the lowest SIB read cost.

[0041] (2) Second priority: Beams that have never been tried are ranked second.

[0042] In some embodiments, the method further includes placing a main information block that exists in the main information block list but has never been tried in the history as the second position. The principle behind this setting is that for beams that have never been tried, the terminal has no negative information about their accessibility; placing them before known failed beams reflects the decision logic of "exploration over repeated failures." In satellite networks, beam status is dynamic. A historically failed beam may become accessible due to UAC parameter adjustments, beam reservation releases, etc., but placing it after beams that have never been tried minimizes the terminal's chances of repeatedly trying known failed beams, thereby reducing the number of invalid SIB reads.

[0043] (3) Third priority: Known failed beams are ranked after the second priority.

[0044] In some embodiments, the method further includes placing master information blocks that exist in the master information block list and have not successfully initiated random access in the history after the second position.

[0045] In some embodiments, the method further includes placing the main information blocks with the same satellite number that have not successfully initiated random access at the end of the main information block list when the number of main information blocks attempted before the last random access attempt exceeds half the total number of main information blocks in the current main information block list, and when two or more beams under the same satellite number are determined to be disallowed from initiating random access, at the end of the main information block list. The principle behind this setting is that in a satellite network, multiple beams belong to the same satellite, and the onboard base station processing capacity, UAC configuration, and beam reservation strategy of a satellite are often uniformly configured. Therefore, when multiple beams under the same satellite are determined to be disallowed from access, this is not an isolated incident, but rather reflects that the satellite as a whole may be under high load, or that strict UAC parameters are configured for that area, or that the entire beam of that satellite may be reserved by the operator. In this case, moving all beams under that satellite number that have not successfully initiated random access to the end of the list allows the terminal to prioritize trying beams from other satellites, thereby avoiding repeated invalid attempts under a satellite with an "overall unfavorable" situation.

[0046] In some embodiments, the operation of placing master information blocks with the same satellite number as the one that has not successfully initiated random access in the history list at the end of the master information block list does not apply to master information blocks that have successfully initiated random access in the history list; master information blocks that have successfully initiated random access remain at the top of the master information block list. The principle behind this setting is that if a beam has successfully accessed the network, it means that the satellite to which that beam belongs has at least once had the capability to provide access services in the beam's coverage area. Even if other beams under the same satellite fail, the successful beam remains the most valuable candidate. Its failure probability is far lower than other beams under the same satellite that have never succeeded. Exempting successful beams from satellite-level downweighting ensures that valuable historical success experience is not overwhelmed by information about a group of failures.

[0047] Step S4: Following the updated order, obtain the corresponding system information blocks according to the time and frequency information carried by each main information block to determine whether the current beam allows random access to be initiated, until random access is successfully initiated or the main information block list is traversed, and update the historical record according to the judgment result.

[0048] The terminal retrieves the corresponding SIB according to the time-frequency information carried by each MIB in the updated MIB list, following the order of the MIBs. Based on the retrieved SIBs, it determines whether the current beam allows random access. To determine whether random access is allowed, all of the following conditions must be met: the received signal strength is greater than or equal to the minimum beam threshold configured in the system information block; network access is permitted; unified access control requirements are met; and beam reservation indication requirements are met.

[0049] If the current beam meets all the above conditions, the terminal initiates random access on that beam and adds a flag indicating that random access was successfully initiated to that beam. If the current beam does not meet any of the above conditions, a flag indicating that random access was unsuccessfully initiated is added to that beam. The terminal continues to try the next MIB in the MIB list until it successfully initiates random access or traverses the entire MIB list. The terminal updates the history and synchronously records the current time information.

[0050] If the terminal fails to initiate random access after traversing all MIBs in the MIB list, the terminal will trigger a full network re-search.

[0051] The technical solution of this application will be described in detail below with reference to a specific application scenario.

[0052] First, it's important to clarify that in 5G NR and satellite communication systems, MIBs are not broadcast uniformly by the cell. Instead, they are bound to Synchronization Signal Blocks (SSBs) and transmitted via beam scanning. The multiple MIBs detected by the terminal within its receiving window are actually MIBs from beams in different directions. The MIB list is essentially a list of beams that the terminal can currently detect.

[0053] Suppose a satellite in a satellite network generates 5 beams, denoted as beam A, beam B, beam C, beam D, and beam E. Beams A, B, and D belong to satellite 1, while beams C and E belong to satellite 2. The terminal sorts the physical broadcast channels corresponding to each MIB from strongest to weakest power to form an initial MIB list. Assuming the power from strongest to weakest is: beam B, beam A, beam C, beam D, beam E, then the initial MIB list is: [beam B, beam A, beam C, beam D, beam E].

[0054] Table 1 shows the historical records stored in the assumed terminal.

[0055]

[0056] Based on the above historical records, the terminal rearranges the initial MIB list: First priority: historically successful beams are listed first. Beam A has successfully initiated random access in the history and has been moved to the first position. The updated MIB list is: [Beam A, Beam B, Beam C, Beam D, Beam E].

[0057] Second priority: Beams that have never been tried are placed in second place. Beam C, which has never been tried, has been promoted to second place. The updated MIB list is: [Beam A, Beam C, Beam B, Beam D, Beam E].

[0058] Third priority: Beams known to have failed are ranked after the second priority. Beams B, D, and E are all in a failed state in the historical records, so they are ranked after beam C. The list becomes: [Beam A, Beam C, Beam B, Beam D, Beam E].

[0059] Next, satellite-level weighting is determined. Condition 1 is met: the number of previously attempted MIBs (4: A, B, D, E) exceeds half of the current total list (5); Condition 2 is met: more than two beams failed under the same satellite number: B and D (2) failed under satellite 1, and E (1) failed under satellite 2. Therefore, satellite 1 is deemed not allowed to initiate random access because it has two or more failed beams. Satellite-level weighting is triggered, moving all beams that failed to initiate random access under satellite 1 to the end of the list. In this embodiment, beams B and D are moved to the end of the list. The final MIB list is: [beam A, beam C, beam E, beam B, beam D].

[0060] The terminal attempts to access the network in the order of the final MIB list: First, it obtains the MIB corresponding to beam A. Based on the time-frequency information carried by the MIB corresponding to beam A, it obtains the corresponding SIB to determine whether the current beam allows random access. If the access conditions are met, the terminal initiates random access on beam A. If the access conditions are not met, the terminal obtains the MIB corresponding to beam C in sequence. Based on the time-frequency information carried by the MIB corresponding to beam C, it obtains the corresponding SIB to determine whether the current beam allows random access. This process continues until random access is successfully initiated or the final MIB list has been traversed.

[0061] This example clearly demonstrates that the initial list sorted by power is [B, A, C, D, E]; after historical data rearrangement, the final list becomes [A, C, E, B, D]. The sorting criterion changes from "power strength" to "historical success > never tried > historical failure (non-demotion) > historical failure (demotion)," fully showcasing the entire hierarchy of the multi-level priority sorting mechanism of this invention. Beam B drops from first to fourth place, clearly demonstrating the actual effect of the satellite-level demotion rule: a beam ranked high in power is dragged down due to the collective failure of multiple beams under the same satellite. Although beam E is also in a failed state, it is not demotioned because it belongs to satellite 2, and satellite 2 has only one failed beam, thus moving it relatively forward. This reflects that satellite-level demotion is a "group decision" rather than "individual punishment." Only when the number of failed beams under the same satellite exceeds a threshold is overall demotion triggered.

[0062] In some embodiments, a time validity management mechanism is introduced for the history records: the terminal records time information synchronously when updating the history records; when the terminal performs a cell search again, if the difference between the current time and the time information corresponding to the most recent successful random access in the history records exceeds a preset time threshold, then all history records are cleared.

[0063] The "Time Information for the Most Recent Successful Initiation of Random Access" refers to the latest timestamp of a successful random access attempt in all historical records (corresponding to timestamp T0 for beam A in the table above), i.e., the moment the terminal last successfully accessed the network. The intention behind this design is that if the terminal has not successfully accessed the network for a long time, it indicates that the network environment may have changed significantly (such as satellite switching, UAC parameter adjustments, changes in beam coverage area, etc.), and the historical records may be invalid and need to be cleared.

[0064] Unlike terrestrial communication networks, satellite ephemeris and beam coverage are dynamic. In low Earth orbit (LEO) satellite communications, satellites are constantly moving, and the ground area covered by a beam changes over time. A beam may be accessible to a terminal's area at a certain moment, but tens of minutes later, as the satellite moves, the same beam may no longer cover that area. Secondly, the system message configuration of satellite networks is not static. Network operators may adjust UAC parameters, change beam reservation status, or adjust beam coverage as needed. If terminals rely indefinitely on outdated historical records, they may make incorrect decisions based on invalid information. Without a timely mechanism, once a satellite or beam is marked as "unaccessible" due to temporary maintenance, congestion, or misconfiguration, even if the network recovers, the terminal may forever avoid it due to rigidly memorizing historical records.

[0065] The preset time threshold can be flexibly set according to the satellite type and network configuration. For example, for geostationary orbit (GEO) satellites, the preset time threshold can be set to a longer value (e.g., 24 hours); for low Earth orbit (LEO) satellites, it should be set to a shorter value (e.g., 30 minutes to 2 hours). The terminal can also dynamically adjust the threshold value based on its own movement speed and satellite ephemeris information.

[0066] The terminal access method of this application introduces historical records, enabling the terminal to prioritize access to master information blocks that have been successfully accessed in the past when performing cell search again, based on whether random access has been successfully initiated on the beam corresponding to each master information block in the historical records. After each access attempt, the historical records are updated according to the judgment results, forming a closed-loop learning mechanism. This reduces the number of times the terminal reads invalid system information blocks at the source, reduces access latency and power consumption, and improves the success rate of network access under satellite network conditions.

[0067] Secondly, this application employs a multi-level priority ranking mechanism, further distinguishing between untried beams and known failed beams after historically successful beams. Untried beams are ranked second, and known failed beams are ranked after the second, reflecting the decision-making logic of "exploration over repeated failures." This minimizes the terminal's repeated attempts at known failed beams, thereby further reducing the number of invalid system information block reads and access latency. Simultaneously, this application uses a satellite-level deweighting rule. When the number of master information blocks attempted before the last random access attempt exceeds half the total number of master information blocks in the current master information block list, and two or more beams under the same satellite number are deemed not allowed to initiate random access, all beams under that satellite number that have not successfully initiated random access are moved to the end of the list. This allows the terminal to utilize the collective failure information of multiple beams under the same satellite to assist individual decision-making, avoiding repeated invalid attempts under an overall unfavorable satellite. Furthermore, beams that have successfully initiated random access are unaffected by this satellite-level deweighting rule and remain ranked first, ensuring that valuable historical successes are not overwhelmed by collective failure information, thus balancing the preservation of collective intelligence and individual success experience.

[0068] Furthermore, this application employs a timeliness management mechanism to enable the terminal to synchronously record time information when updating historical records. When performing cell searches again, it determines whether the difference between the current time and the time information corresponding to the most recent successful random access in the historical records exceeds a preset time threshold. If it does, all historical records are cleared, thereby preventing the terminal from indefinitely relying on outdated historical records and causing "historical deadlock," i.e., permanently avoiding a certain beam or satellite due to a one-time temporary network failure. This ensures that the terminal can automatically forget outdated information and adaptively restore its responsiveness to changes in network status when network configuration changes (such as UAC parameter adjustments or changes in beam reservation status) or satellite beam coverage areas change (such as low Earth orbit satellites moving and causing the beam to no longer cover the current location).

[0069] It should be noted that existing technologies include schemes that utilize historical information to assist cell selection. For example, they use operator information of the Public Land Mobile Network (RPLMN) registered before the terminal was last powered off or disconnected from the network to narrow down the frequency scanning range, and then sort the frequency points obtained from the frequency scanning according to signal strength before selecting a cell. However, this scheme is fundamentally different from that of this application: First, existing technologies are geared towards terrestrial cellular networks, while this application is geared towards satellite networks. Terrestrial cellular networks and satellite networks differ fundamentally in their communication characteristics. Terrestrial networks have fixed base station locations, relatively stable beam coverage areas, and low propagation delays (typically within milliseconds), while satellite networks have beam coverage areas that change rapidly with satellite movement (especially low Earth orbit satellites), propagation delays as high as hundreds of milliseconds, and terminals may face frequent beam switching and dynamic adjustments to network configurations. Furthermore, the unique Unified Access Control (UAC) and beam reservation indication (beamReservedForOperatorUse) mechanisms in satellite networks mean that even if a terminal's signal strength meets the requirements, it may still be denied access. Therefore, solutions designed based on the characteristics of terrestrial cellular networks cannot be directly migrated to satellite networks.

[0070] Secondly, existing technologies do not involve updating the search order. They only use historical information to narrow down the initial frequency sweep range. After the frequency sweep is completed, the frequency points are sorted once according to the signal strength. After that, the sorting is not adjusted according to any feedback information. In contrast, this application dynamically adjusts the attempt order of the MIB list according to the historical record. After each access attempt, the historical record is updated according to the judgment result, forming a closed-loop learning mechanism of "attempt-feedback-optimization". The sorting is a dynamic and continuously evolving process.

[0071] Furthermore, regarding the use of historical information, existing technologies use it to narrow the frequency sweep range, while this application uses it to adjust the attempt order of the MIB list, prioritizing beams that have been successfully accessed in the past; in terms of sorting criteria, existing technologies sort by signal strength, while this application sorts by historical access success markers.

[0072] In summary, those skilled in the art have no incentive to migrate existing solutions for terrestrial cellular networks that do not involve sorting updates and utilize operator information to narrow the frequency sweep range to satellite networks with vastly different communication characteristics.

[0073] This application also provides a terminal device 300. For example... Figure 3 As shown, the terminal device 300 includes a bus 301, a processor 302, a memory 304, and a communication interface 303. The processor 302, the memory 304, and the communication interface 303 communicate with each other via the bus 301. It should be understood that this application does not limit the number of processors and memories in the terminal device 300.

[0074] Bus 301 can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, Figure 3 The bus 301 may be represented by a single line, but this does not mean that there is only one bus or one type of bus. The bus 301 may include a path for transmitting information between various components of the terminal device 300 (e.g., memory 304, processor 302, communication interface 303).

[0075] Processor 302 may include any one or more processors such as a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor (MP), or a digital signal processor (DSP).

[0076] Memory 304 may include volatile memory, such as random access memory (RAM). Processor 302 may also include non-volatile memory, such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid state drive (SSD).

[0077] The memory 304 stores executable program code, which the processor 302 executes to implement the aforementioned methods for terminal access to the satellite network. That is, the memory 304 stores instructions for executing the methods for terminal access to the satellite network.

[0078] The communication interface 303 uses transceiver modules such as, but not limited to, network interface cards and transceivers to enable communication between the terminal device 300 and other devices or communication networks.

[0079] Specifically, processor 302 performs the following steps: When the terminal device performs cell search again, it acquires one or more MIBs and sorts them from strongest to weakest according to the power of the physical broadcast channel corresponding to each MIB, forming a MIB list. The order of each MIB in the MIB list is updated according to historical records, with MIBs that exist in the MIB list and have successfully initiated random access in the historical records placed at the top of the MIB list. Following the updated order, the corresponding SIBs are acquired sequentially based on the time-frequency information carried by each MIB to determine whether the current beam allows random access, until random access is successfully initiated or the MIB list has been traversed, and the historical records in the memory are updated according to the determination results.

[0080] Furthermore, the processor performs the following steps: when updating the order of MIBs in the MIB list according to historical records, MIBs that exist in the MIB list but have never been tried in the historical records are placed in the second position. MIBs that exist in the MIB list but have not successfully initiated random access in the historical records are placed after the second position.

[0081] If the number of MIBs that attempted random access before the last attempt exceeds half the total number of MIBs in the current MIB list, and two or more beams under the same satellite number are determined to be disallowed from initiating random access, then the MIBs with the same satellite number that have not successfully initiated random access in the history will be placed at the end of the MIB list.

[0082] The operation of placing MIBs with the same satellite number as the MIB in the MIB list at the end of the MIB list that have not successfully initiated random access in the history does not apply to MIBs that have successfully initiated random access in the history. MIBs that have successfully initiated random access will remain at the top of the MIB list.

[0083] Furthermore, the memory records time information synchronously when updating historical records. When the terminal device performs a cell search again, if the difference between the current time and the time corresponding to the most recent successful random access in the historical records exceeds a preset time threshold, the processor clears all historical records in the memory.

[0084] This application also provides a computer-readable storage medium. The computer-readable storage medium can be any available medium that a network device can store, or a data storage device such as a data center that contains one or more available media. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives). The computer-readable storage medium includes instructions that instruct the network device to perform a method for a terminal to access a satellite network.

[0085] This application also provides a computer program product containing instructions. The computer program product may be software or program products containing instructions, capable of running on a network device or stored on any usable medium. When the computer program product runs on at least one network device, it causes the at least one network device to perform a method for a terminal to access a satellite network.

[0086] Flowcharts are used in this application to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, various steps can be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0087] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

[0089] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0090] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for a terminal to access a satellite network, characterized in that, include: The terminal obtains historical records, which are used to record whether random access has been successfully initiated on the beam corresponding to the main information block; When the terminal performs cell search again, it acquires one or more master information blocks and sorts them according to the power of the physical broadcast channel corresponding to each master information block to form a master information block list. The order of each main information block in the main information block list is updated according to the historical record, wherein the main information block that exists in the main information block list and has successfully initiated random access in the historical record is placed at the top of the main information block list; Following the updated order, the corresponding system information blocks are obtained sequentially based on the time and frequency information carried by each main information block to determine whether the current beam allows random access to be initiated, until random access is successfully initiated or the list of main information blocks has been traversed, and the historical record is updated based on the determination result.

2. The method as described in claim 1, characterized in that, The order of updating the main information blocks in the main information block list according to the historical record also includes: placing the main information blocks that exist in the main information block list but have never been tried in the historical record in the second position.

3. The method as described in claim 2, characterized in that, The order in which the main information blocks in the main information block list are updated according to the historical record also includes: The main information blocks that exist in the list of main information blocks and have not successfully initiated random access in the history are placed after the second position.

4. The method as described in claim 1, characterized in that, The order in which the main information blocks in the main information block list are updated according to the historical record also includes: If the number of master information blocks attempted before the last random access attempt exceeds half the total number of master information blocks in the current master information block list, and more than or equal to two beams under the same satellite number are determined to be not allowed to initiate random access, then the master information blocks with the same satellite number that have not successfully initiated random access in the historical records will be placed at the end of the master information block list.

5. The method as described in claim 4, characterized in that, The operation of placing the main information block with the same satellite number as the satellite in the main information block list at the end of the main information block list that has not successfully initiated random access in the historical record does not apply to main information blocks that have successfully initiated random access in the historical record. The main information blocks that have successfully initiated random access remain at the top of the main information block list.

6. The method as described in claim 1, characterized in that, Also includes: When updating the historical records, the terminal simultaneously records time information. When the terminal performs a cell search again, if the difference between the current time and the time information corresponding to the most recent successful random access in the historical record exceeds a preset time threshold, then all the historical records are cleared.

7. The method as described in claim 1, characterized in that, To determine whether random access is allowed for the current beam, the following conditions must be met: the received signal strength is greater than or equal to the minimum beam threshold configured in the system information block, network access is allowed, unified access control requirements are met, and beam reservation indication requirements are met.

8. The method as described in claim 1, characterized in that, When performing a cell search for the first time, the terminal acquires one or more master information blocks and sorts them according to the power of the physical broadcast channel corresponding to the master information blocks to form a master information block list; The corresponding system information block is obtained sequentially based on the time and frequency information carried by each main information block, it is determined whether the current beam allows random access, and the historical record is generated based on the determination result.

9. A terminal device, characterized in that, include: A memory that stores computer-executable instructions; A processor, the processor being configured to execute computer-executable instructions stored in the memory to cause the terminal device to perform the method as described in any one of claims 1-8.

10. A computer-readable medium, characterized in that, Includes computer program instructions, which, when executed by a processor, cause the processor to perform the method as described in any one of claims 1-8.

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