Communication method and apparatus

Abstract

A communication method and apparatus. A terminal device can quickly and easily determine a second frequency point, so as to reduce an access delay of the terminal device. The method comprises: a terminal device receives, on a first frequency point, a first synchronization signal block from a first access network device, wherein the first synchronization signal block comprises information of a second frequency point, the second frequency point is different from the first frequency point, and the search priority of the first frequency point is higher than that of the second frequency point; subsequently, the terminal device receives, on the second frequency point, a second synchronization signal block from a second access network device, and accesses the second access network device on the basis of the second synchronization signal block.

Description

Communication method and apparatus

[0001] This application claims priority to the Chinese Patent Application No. 202510240861.5, filed on February 28, 2025, and entitled "Communication method and apparatus", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] Embodiments of the present application relate to the field of communication, and in particular, to a communication method and apparatus. BACKGROUND

[0003] In a satellite communication scenario, a terminal device searches for a synchronization signal block (SSB) according to some frequency points indicated in an SSB raster. Specifically, the terminal device can search for the SSB on the frequency points indicated by the SSB raster in turn, and if the terminal device does not search for the SSB within a certain time window, the terminal device will search for the SSB on the next frequency point.

[0004] However, the coverage area of a satellite is usually large, but the number of downlink beams of the satellite is limited, so in the satellite communication scenario, the period of the SSB is usually set to be large. If the terminal device searches for the SSB in the above manner, the access latency of the terminal device will be increased, and the user experience will be affected. SUMMARY

[0005] The present application provides a communication method and apparatus, which can enable a terminal device to quickly and easily determine a second frequency point, so as to reduce the access latency of the terminal device.

[0006] In a first aspect, a communication method is provided. The method can be performed by a terminal device, or by a module (such as a processor, a chip, or a chip system, etc.) applied to the terminal device, or by a logic node, a logic module, or software that can realize all or part of the functions of the terminal device. The method comprises: receiving a first synchronization signal block from a first access network device at a first frequency point, the first synchronization signal block comprising information of a second frequency point; the second frequency point is different from the first frequency point, and the search priority of the first frequency point is higher than the search priority of the second frequency point; receiving a second synchronization signal block from a second access network device at the second frequency point, and accessing the second access network device based on the second synchronization signal block.

[0007] In the above technical solution, the first frequency point and the second frequency point are different, and the search priority of the first frequency point is higher than that of the second frequency point. Therefore, the terminal device can first search for the first synchronization signal block on the first frequency point with higher search priority, and the first synchronization signal block can provide the terminal device with information about the second frequency point. In other words, the terminal device can quickly and easily determine the second frequency point based on the first synchronization signal block, reducing the time for the terminal device to determine the second frequency point. Furthermore, the terminal device can directly receive the second synchronization signal block on the second frequency point and access the second access network device, simplifying the complexity of the terminal device searching for the second synchronization signal block, improving the efficiency of the terminal device searching for the second synchronization signal block, and reducing the access latency of the terminal device.

[0008] In conjunction with the first aspect above, in one possible implementation, the information of the second frequency point includes one or more of the following: a first subcarrier offset or first information, wherein the first information is used to indicate the second frequency point; the first subcarrier offset is related to one or more of the following: the synchronization signal block grid corresponding to the second frequency point, or the frequency band to which the second frequency point belongs.

[0009] In the above technical solution, the information of the second frequency point is configured with a synchronization signal block grid corresponding to the second frequency point, or a first subcarrier offset related to the frequency band to which the second frequency point belongs, and / or first information indicating the second frequency point. That is to say, the terminal device can determine the second frequency point based on the above information, so that the terminal device can directly receive the second synchronization signal block on the second frequency point, simplifying the complexity of the terminal device searching for the second synchronization signal block.

[0010] In conjunction with the first aspect described above, in one possible implementation, the information of the second frequency point further includes first indication information, which is used to indicate that the first information is used to indicate the second frequency point.

[0011] In the above technical solution, the first indication information enables the terminal device to know that the first information is used to indicate the second frequency point. In this way, under the instruction of the first indication information, the terminal device can directly determine the second frequency point through the first information without having to calculate the second frequency point, thus simplifying the complexity of the terminal device in determining the second frequency point.

[0012] In conjunction with the first aspect described above, in one possible implementation, the first information is used to schedule the second information, and the second information indicates a second frequency point.

[0013] In the above technical solution, the frequency indication method is not limited by the amount of data in the first information, but can use more data to indicate the second frequency, thus exchanging overhead for a more flexible frequency indication method.

[0014] In conjunction with the first aspect described above, in one possible implementation, both the first frequency point and the second frequency point are frequencies within the first synchronization signal block grid. That is, this technical solution allows setting the search priority for multiple frequency points belonging to the same synchronization signal block grid.

[0015] In conjunction with the first aspect described above, in one possible implementation, the first frequency point is a frequency point in the second synchronization signal block grid, and the second frequency point is a frequency point in the third synchronization signal block grid. The search priority of the frequency point in the second synchronization signal block grid is higher than the search priority of the frequency point in the third synchronization signal block grid. In other words, this technical solution can achieve the division of search priorities between the first and second frequency points by setting the search priorities of each synchronization signal block grid.

[0016] In conjunction with the first aspect described above, in one possible implementation, the first synchronization signal block further includes second indication information, which instructs the first type of terminal device to prohibit access to the first frequency point.

[0017] In the above technical solution, a second indication information can be added to prevent the first type of terminal from misinterpreting the information in the first synchronization signal block and thus accessing the first frequency point.

[0018] In conjunction with the first aspect above, in one possible implementation, the first access network device is a first satellite, the second access network device is a second satellite, and the altitude of the orbit of the first satellite is greater than or equal to the altitude of the orbit of the second satellite.

[0019] In the above technical solution, when the first access network device is the first satellite and the second access network device is the second satellite, and the orbital altitude of the first satellite is greater than that of the second satellite, although the first satellite has a higher orbital altitude and a poorer link budget, its coverage area is larger. For example, when the first satellite detects that the second satellite can cover or is about to cover the area where the terminal device is located, the first satellite can provide the terminal device with information on a second frequency point to assist the terminal device in accessing the satellite and reduce the access latency of the terminal device.

[0020] When the first access network device is the first satellite and the second access network device is the second satellite, and the orbital altitude of the first satellite is equal to that of the second satellite, the first satellite can also provide the terminal device with information on a second frequency point when it detects that the second satellite can cover or is about to cover the area where the terminal device is located. This assists the terminal device in accessing the second satellite and reduces the access latency of the terminal device.

[0021] In other words, the terminal device can quickly access the second satellite under the guidance of the first satellite, realizing the process of the terminal quickly accessing the second satellite in the satellite communication scenario and improving the communication rate.

[0022] Secondly, a communication method is provided. This method can be executed by a first access network device, by a module (e.g., processor, chip, or chip system) applied to the first access network device, or by a logical node, logical module, or software capable of implementing all or part of the functions of the first access network device. The method includes: determining a first synchronization signal block; transmitting the first synchronization signal block on a first frequency point, the first synchronization signal block including information about a second frequency point, the second frequency point being different from the first frequency point, and the search priority of the first frequency point being greater than the search priority of the second frequency point; the second frequency point being used by a terminal device to receive the second synchronization signal block, and the second synchronization signal block being used by the terminal device to access the second access network device. The technical effects of the second aspect are similar to those of the first aspect and will not be elaborated further here.

[0023] In conjunction with the second aspect above, in one possible implementation, the information of the second frequency point includes one or more of the following: a first subcarrier offset or first information, wherein the first information is used to indicate the second frequency point; the first subcarrier offset is related to one or more of the following: the synchronization signal block grid corresponding to the second frequency point, or the frequency band to which the second frequency point belongs.

[0024] In conjunction with the second aspect above, in one possible implementation, the information of the second frequency point further includes first indication information, which is used to indicate that the first information is used to indicate the second frequency point.

[0025] In conjunction with the second aspect above, in one possible implementation, the first information is used to schedule the second information, and the second information indicates a second frequency point.

[0026] In conjunction with the second aspect above, in one possible implementation, both the first frequency point and the second frequency point are frequency points within the first synchronization signal block grid.

[0027] In conjunction with the second aspect above, in one possible implementation, the first frequency point is a frequency point in the second synchronization signal block grid, the second frequency point is a frequency point in the third synchronization signal block grid, and the search priority of the frequency point in the second synchronization signal block grid is greater than the search priority of the frequency point in the third synchronization signal block grid.

[0028] In conjunction with the second aspect above, in one possible implementation, the first synchronization signal block further includes second indication information, which instructs the first type of terminal device to prohibit access to the first frequency point.

[0029] In conjunction with the second aspect above, in one possible implementation, the first access network device is a first satellite, the second access network device is a second satellite, and the altitude of the orbit of the first satellite is greater than or equal to the altitude of the orbit of the second satellite.

[0030] Thirdly, a communication method is provided. This method can be executed by a terminal device, by a module applied to the terminal device (e.g., a processor, chip, or chip system), or by a logical node, logical module, or software capable of implementing all or part of the terminal device's functions. The method includes: receiving a first synchronization signal block from a first access network device at a first frequency point, the first synchronization signal block indicating the time-domain resources of a second synchronization signal block; the time-domain resources of the second synchronization signal block being different from those of the first synchronization signal block; receiving a second synchronization signal block from a second access network device at the first frequency point and on the time-domain resources of the second synchronization signal block; and accessing the second access network device based on the second synchronization signal block.

[0031] In the above technical solution, when both the first access network device and the second access network device transmit synchronization signal blocks on the first frequency point, the first access network device can indicate the time domain resources of the second synchronization signal block to the terminal device through the first synchronization signal block. Furthermore, the time domain resources of the second synchronization signal block are different from those of the first synchronization signal block. This allows the terminal device to receive the second synchronization signal block on the time domain resources of the second synchronization signal block and on the first frequency point, and to access the second access network device. This simplifies the complexity of the terminal device searching for the second synchronization signal block, improves the efficiency of the terminal device searching for the second synchronization signal block, and reduces the access latency of the terminal device.

[0032] In conjunction with the third aspect described above, in one possible implementation, the first synchronization signal block includes third indication information; the third indication information is used to indicate that the frequency point corresponding to the first synchronization signal block is the same as the frequency point corresponding to the second synchronization signal block.

[0033] In the above technical solution, the frequency point corresponding to the first synchronization signal block can be directly indicated to be the same as the frequency point corresponding to the second synchronization signal block through the third indication information, so that the terminal device can clearly receive the second synchronization signal on the first frequency point.

[0034] In conjunction with the third aspect above, in one possible implementation, the first synchronization signal block is used to schedule the third information, which indicates the time-domain resources of the second synchronization signal block.

[0035] In the above technical solution, the time domain resources of the second synchronization signal block are not limited by the amount of data of the first synchronization signal block. Instead, the time domain resources of the second synchronization signal block are indicated by third information (i.e., more data), thus exchanging overhead for a more flexible time domain resource indication method.

[0036] In conjunction with the third aspect above, in one possible implementation, the first access network device is a first satellite, the second access network device is a second satellite, and the altitude of the orbit of the first satellite is greater than or equal to the altitude of the orbit of the second satellite.

[0037] In the above technical solution, when the first access network device is the first satellite and the second access network device is the second satellite, and the orbital altitude of the first satellite is greater than that of the second satellite, although the first satellite has a higher orbital altitude and a poorer link budget, its coverage area is larger. For example, when the first satellite detects that the second satellite can cover or is about to cover the area where the terminal device is located, the first satellite can provide the terminal device with information on a second frequency point to assist the terminal device in accessing the satellite and reduce the access latency of the terminal device.

[0038] When the first access network device is the first satellite and the second access network device is the second satellite, and the orbital altitude of the first satellite is equal to that of the second satellite, the first satellite can also provide the terminal device with information on a second frequency point when it detects that the second satellite can cover or is about to cover the area where the terminal device is located. This assists the terminal device in accessing the second satellite and reduces the access latency of the terminal device.

[0039] In other words, the terminal device can quickly access the second satellite under the guidance of the first satellite, realizing the process of the terminal quickly accessing the second satellite in the satellite communication scenario and improving the communication rate.

[0040] Fourthly, a communication method is provided. This method can be executed by a first access network device, by a module (e.g., processor, chip, or chip system) applied to the first access network device, or by a logical node, logical module, or software capable of implementing all or part of the functions of the first access network device. The method includes: determining a first synchronization signal block; transmitting the first synchronization signal block on a first frequency point; the first synchronization signal block being used to indicate the time-domain resources of a second synchronization signal block; the time-domain resources of the second synchronization signal block being different from the time-domain resources of the first synchronization signal block; and the second synchronization signal block being used by a terminal device to access the second access network device.

[0041] The technical effects of the fourth aspect can be referenced from those of the third aspect, and will not be elaborated further here.

[0042] In conjunction with the fourth aspect above, in one possible implementation, the first synchronization signal block includes third indication information; the third indication information is used to indicate that the frequency point corresponding to the first synchronization signal block is the same as the frequency point corresponding to the second synchronization signal block.

[0043] In conjunction with the fourth aspect above, in one possible implementation, the first synchronization signal block is used to schedule the third information, which indicates the time-domain resources of the second synchronization signal block.

[0044] In conjunction with the fourth aspect above, in one possible implementation, the first access network device is a first satellite, the second access network device is a second satellite, and the altitude of the orbit of the first satellite is greater than or equal to the altitude of the orbit of the second satellite.

[0045] Fifthly, a communication device is provided for implementing various methods. The communication device includes modules, units, or means corresponding to the implementation of the methods, which can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the functions.

[0046] In some possible designs, the communication device may include a processing module and a transceiver module. The processing module can be used to implement the processing functions in any of the above aspects and any possible implementations thereof. The transceiver module may include a receiving module and a transmitting module, respectively used to implement the receiving function and the transmitting function in any of the above aspects and any possible implementations thereof.

[0047] In some possible designs, the transceiver module may include transceiver circuitry, a transceiver, a transceiver unit, or a communication interface.

[0048] A sixth aspect provides a communication device, comprising: a processor and a memory; the memory being used to store computer instructions that, when executed by the processor, cause the communication device to perform the method described in either aspect.

[0049] A seventh aspect provides a communication device, comprising: a processor and a communication interface; the communication interface being used to communicate with a module outside the communication device; the processor being used to execute a computer program or instructions to cause the communication device to perform the method described in any aspect.

[0050] Eighthly, a communication device is provided, comprising: at least one processor; said processor being configured to execute a computer program or instructions stored in a memory to cause the communication device to perform the method described in any of the aspects. The memory may be coupled to the processor, or may be independent of the processor.

[0051] A ninth aspect provides a communication device (e.g., the communication device may be a chip or a chip system), the communication device including a processor for implementing the functions involved in any one of the first to sixth aspects.

[0052] In some possible designs, the communication device includes a memory for storing necessary program instructions and data.

[0053] In some possible designs, when the device is a chip system, it can be composed of chips or contain chips and other discrete components.

[0054] It is understood that the communication device provided in the fifth to ninth aspects may be a terminal device as described in the first or third aspect, or a module or unit (e.g., a chip, chip system, or circuit) in the terminal device that performs the methods / operations / steps / actions described in the first or third aspect, or a module or unit that can be used in conjunction with the terminal device, or a logical node, logical module, or software that can realize all or part of the functions of the terminal device; or, the communication device may be a first access network device as described in the second or fourth aspect, or a module or unit (e.g., a chip, chip system, or circuit) in the first access network device that performs the methods / operations / steps / actions described in the second or fourth aspect, or a module or unit that can be used in conjunction with the first access network device, or a logical node, logical module, or software that can realize all or part of the functions of the first access network device.

[0055] It is understandable that when the communication device provided in any of the fifth to ninth aspects is a chip, the sending action / function of the communication device can be understood as outputting information, and the receiving action / function of the communication device can be understood as inputting information.

[0056] In a tenth aspect, a computer-readable storage medium is provided, which stores a computer program or instructions that, when executed on a communication device, enable the communication device to perform the method described in any one of the first to fourth aspects.

[0057] Eleventhly, a computer program product containing instructions is provided, which, when run on a communication device, enables the communication device to perform the method described in any one of the first to fourth aspects.

[0058] In a twelfth aspect, a communication system is provided, comprising a terminal device and a first access network device. The terminal device is configured to perform the methods described in the first aspect and any possible embodiments thereof, and the first access network device is configured to perform the methods described in the second aspect and any possible embodiments thereof; or, the terminal device is configured to perform the methods described in the third aspect and any possible embodiments thereof, and the first access network device is configured to perform the methods described in the fourth aspect and any possible embodiments thereof.

[0059] The technical effects of any one of the fifth to twelfth aspects can be found in the technical effects of different embodiments in the first to fourth aspects, and will not be repeated here. Attached Figure Description

[0060] Figure 1 is a schematic diagram of the architecture of a communication system provided in this application;

[0061] Figure 2 is a schematic diagram of the architecture of the satellite communication system provided in this application;

[0062] Figures 3 and 4 are schematic flowcharts of the communication method provided in this application;

[0063] Figure 5 is a schematic diagram of a time-domain window provided in this application;

[0064] Figures 6-8 are schematic diagrams of the communication device provided in this application. Detailed Implementation

[0065] In the description of this application, unless otherwise stated, " / " indicates that the objects before and after are in an "or" relationship. For example, A / B can mean A or B. "And / or" in this application is merely a description of the relationship between the related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural.

[0066] In the description of this application, unless otherwise stated, "multiple" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0067] Furthermore, to facilitate a clear description of the technical solutions in the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish identical or similar items with substantially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and the terms "first" and "second" are not necessarily different.

[0068] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner to facilitate understanding.

[0069] It is understood that the term "embodiment" used throughout the specification means that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, various embodiments throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It is understood that in the various embodiments of this application, the sequence number of each process 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.

[0070] It is understood that in this application, "...when" and "if" both refer to the corresponding processing that will be carried out under certain objective circumstances, and are not limited to a specific time, nor do they require a judgment action to be performed during implementation, nor do they imply any other limitations.

[0071] It is understood that some optional features in the embodiments of this application can be implemented independently in certain scenarios without relying on other features, such as the current solution on which they are based, to solve the corresponding technical problems and achieve the corresponding effects. Alternatively, they can be combined with other features as needed in certain scenarios. Correspondingly, the apparatus given in the embodiments of this application can also implement these features or functions, which will not be elaborated here.

[0072] In this application, unless otherwise specified, the same or similar parts between the various embodiments can be referred to each other. In the various embodiments of this application, unless otherwise specified or there is a logical conflict, the terminology and / or descriptions between different embodiments are consistent and can be mutually referenced. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships. The following descriptions of the embodiments of this application do not constitute a limitation on the scope of protection of this application.

[0073] To facilitate understanding of the technical solutions of the embodiments of this application, a brief introduction to the relevant technologies of this application is given below.

[0074] I. Synchronization signal block grid:

[0075] Synchronization block grids are a method used in communication systems to organize and manage synchronization block resources. By allocating frequency resources, synchronization block grids enable access network devices to efficiently and periodically broadcast signals, thereby helping terminal devices quickly achieve synchronization during initial and random access. Specifically, terminal devices receive downlink synchronization blocks using frequencies within the synchronization block grid, and access network devices can also transmit downlink synchronization blocks at frequencies within the grid, thus aligning the terminal devices' and access network devices' perceptions of the possible frequency domain locations of downlink synchronization blocks.

[0076] As shown in Table 1, the operating frequency band, subcarrier spacing (SCS), and block pattern of non-terrestrial network (NTN) satellites are specified. 1 ), and the range of the Global Synchronization Channel Number (GSCN) (first value – <step size> – last value).

[0077] Table 1 specifically shows the two frequency bands (n256 and n255) of the non-terrestrial network satellite operating frequency bands. For the subcarrier spacing of the synchronization signal block, Table 1 shows a subcarrier spacing of 15kHz for the n256 band; and for the n255 band, Table 1 shows two subcarrier spacings: 15kHz and 30kHz. Different subcarrier spacings affect signal transmission efficiency, bandwidth usage, and adaptability to factors such as Doppler shift. The table shows two types of synchronization signal blocks: Case A and Case B. These types define the distribution of synchronization signal blocks on time-frequency resources. For example, Case A is generally used for frequency range 1 (FR1) with a subcarrier spacing of 15kHz; Case B is generally used for FR1 with a subcarrier spacing of 30kHz. Regarding the range of global synchronization channel numbers, for the n256 band, when the subcarrier spacing is 15kHz and the synchronization block type is Case A, the range of global synchronization channel numbers is from 5429 to 5494, with a step size of 1; for the n255 band, when the subcarrier spacing is 15kHz and the synchronization block type is Case A, the range of global synchronization channel numbers is from 3818 to 3892, with a step size of 1; for the n255 band, when the subcarrier spacing is 30kHz and the synchronization block mode is Case B, the range of global synchronization channel numbers is from 3824 to 3886, with a step size of 1.

[0078] Understandably, the range of Global Synchronization Channel Numbers (GSCNs) is used to determine the frequency resources used by synchronization signals (such as the primary synchronization signal (PSS) and secondary synchronization signal (SSS)). The range of GSCNs is part of the network frequency configuration and assists terminal equipment in determining the correct synchronization signal. Specifically, the GSCN specifies the resource block selected by the access network equipment for the synchronization signal in the frequency domain. The range of GSCNs varies depending on the subcarrier spacing configuration.

[0079] Table 1

[0080] II. Master Information Block (MIB):

[0081] The master information block is a key broadcast information block in a communication system. It contains basic cell information, such as cell identifier, system frame number, subcarrier spacing, bandwidth configuration, and one or more other details. When a terminal device accesses the network, it first needs to receive the master information block. The downlink synchronization signal and the master information block together form the downlink synchronization block, which is periodically broadcast through the physical broadcast channel. It is a critical data block in the terminal device's initialization, synchronization, and access processes.

[0082] The main information block includes one or more of the following: subcarrier offset (SS block subcarrier offset, Kssb) or indication information (pdcch-ConfigSIB1). Kssb is a key parameter in the main information block, representing the subcarrier offset of subcarrier 0 of the synchronization signal block relative to subcarrier 0 of the entire channel bandwidth. In 5G NR, the value of Kssb generally ranges from 0 to a certain integer. pdcch-ConfigSIB1 is a field in the main information block used to indicate frequency resources for common control signals and for scheduling broadcast messages. Currently, pdcch-ConfigSIB1 is 8 bits in size.

[0083] III. Synchronization Signal Block:

[0084] Synchronization signal blocks include cell-defining SSBs (CD-SSBs) and non-cell-defining SSBs (NCD-SSBs). Cell-defining SSBs are used for downlink synchronization and cell access. Specifically, during network access, terminal devices can detect cell-defining SSBs to achieve cell synchronization, complete the access process, obtain relevant system information about the cell, and establish a connection with the network. Non-cell-defining SSBs are primarily used for downlink synchronization and are suitable for terminal devices already connected to the network. However, for terminal devices not yet connected, if a non-cell-defining SSB is detected, it can provide information about the frequency points of nearby access-related synchronization blocks, preparing for the subsequent access process.

[0085] The frequency information provided by non-cell-defined synchronization signal blocks is determined by the value of Kssb in the MIB. Terminal devices can determine whether the current synchronization signal block is a non-cell-defined synchronization signal block by using the value of Kssb.

[0086] As shown in Table 2, for the FR1 band, a Kssb value greater than or equal to 24 and less than or equal to 29 (i.e., 24 <= Kssb <= 29) indicates that the current synchronization signal block is a non-cell-defined synchronization signal block. Kssb also indicates the next nearest cell-defined synchronization signal block; for example, the location of the next nearest synchronization signal block can be calculated by consulting Table 2. Table 2 reserves the pdcch-ConfigSIB1 and offset units corresponding to a Kssb value of 30. Multiple reserved bits are used to facilitate future functional expansion. For example, when expanding the configuration scheme of the synchronization signal block, a specific Kssb value is needed to adapt to the new time-frequency resource allocation. In this case, the reserved value when Kssb is 30 can be used. As shown in Table 3, for the FR2 band, if the Kssb value is greater than or equal to 12 and less than or equal to 13 (i.e., 12 <= Kssb <= 13), it indicates that the current synchronization signal block is a non-cell-defined synchronization signal block. Kssb is also used to indicate the next nearest cell-defined synchronization signal block. For example, the location of the next nearest synchronization signal block can be calculated by referring to Table 3. Table 3 reserves pdcch-ConfigSIB1 and the number of offset units corresponding to a Kssb value of 14. Multiple reserved bits are used to facilitate future functional expansion. For example, when expanding the configuration scheme of the synchronization signal block, a specific Kssb value is required to adapt to the new time and frequency resource allocation. In this case, the reserved value when Kssb is 14 can be used.

[0087] In Tables 2 and 3, the first column represents the value of Kssb, the second column represents the parameter indicated by the MIB (pdcch-ConfigSIB1), and the third column represents the number of units of offset. The number of units of this offset is used to calculate the frequency domain location of the nearest SSB. This can be determined by combining the value of Kssb and pdcch-ConfigSIB1. For example, taking Kssb as 24 and pdcch-ConfigSIB1 as 255 as an example, then according to Table 2, It is the 255th value in (1,2,...,256), which is 256.

[0088] Furthermore, in determining the number of units of offset. After that, it can be based on Calculate the frequency domain locations of neighboring SSBs. For example, the frequency domain locations of SSBs and... The following relationship can be satisfied:

[0089] in, This indicates the channel grid frequency corresponding to the currently received SSB. The unit representing the offset.

[0090] Additionally, pdcch-ConfigSIB1 can include a control resource set 0 (controlResourceSetZero) and a search space 0 (searchSpaceZero). Control resource set 0 is used to determine the number of frequency domain resource blocks, the number of symbols, and the frequency domain offset of the control resource set, while search space 0 is used to determine the timing of time domain monitoring, such as slot offsets and symbol positions.

[0091] Table 2

[0092] Table 3

[0093] For cell-defined synchronization signal blocks, the value range of Kssb is 0~23 and 0~11. It is used to indicate the subcarrier index of the synchronization signal block and the subcarrier offset from subcarrier 0 to subcarrier 0 of the synchronization signal block, and is used to indicate the actual subcarrier index to the terminal equipment.

[0094] Satellite communication offers unique advantages over terrestrial communication. Firstly, it provides wider coverage, and satellite access network equipment (such as base stations) is less susceptible to damage from natural disasters or external forces. Secondly, integrating satellite communication into future 5G networks can provide services to areas such as oceans and forests that terrestrial networks cannot cover. It also enhances the reliability of 5G communication, providing passengers on airplanes and trains with a superior communication experience and ensuring stable communication in critical scenarios. Furthermore, satellite communication can provide more data transmission resources for 5G, significantly improving network speeds and meeting the ever-increasing data demands.

[0095] Therefore, supporting collaborative communication between terrestrial and satellite systems is an inevitable direction for the future development of communications. This convergence model can bring significant benefits in terms of expanding coverage, enhancing reliability, enabling multiple connections, and improving throughput, injecting strong momentum into the continuous innovation and development of the communications field.

[0096] In satellite communication scenarios, terminal devices search for SSBs based on frequency points indicated in the synchronization signal block grid. Specifically, the terminal device can sequentially search for SSBs on the frequency points indicated by the SSB grid, and if the terminal device does not find an SSB within a certain time window, it will switch to the next frequency point to search for an SSB.

[0097] However, satellites typically cover a large area, but the number of downlink beams is limited. Therefore, in satellite communication scenarios, the SSB period is usually set to a relatively long value. If the terminal device searches for the SSB in the above manner, it will increase the access latency of the terminal device and affect the user experience.

[0098] Specifically, the current SSB period is generally in the range of 20 milliseconds (ms) to 160 ms. This period range exists in satellite communication because of its unique characteristics. Since satellites typically cover a large area, but the number of downlink beams is limited, it's difficult to ensure that satellites can scan and transmit SSBs within their coverage area at very short periods (e.g., 20 ms). Therefore, in satellite communication, the SSB period is usually set to be longer. Because the SSB period is longer, the time it takes for the terminal device to search for cells also increases. This is because the terminal device must first receive SSBs on at least one frequency point based on the preset period; only if no SSB is received within this period will it switch to the next frequency point to receive SSBs.

[0099] Furthermore, in the early stages of constellation establishment, satellite coverage is not continuous. When a terminal device searches for a signal on a frequency, if the satellite has not yet moved to an area that covers the terminal device, the terminal device cannot find the SSB based on that frequency. If the terminal device does not receive the SSB within a certain time window, it will switch to the next frequency to continue searching. When the satellite finally moves to an area that covers the terminal device, the terminal device has already switched to the next frequency to search for a signal, which further increases the access latency of the terminal device and affects the user experience.

[0100] In view of this, this application provides a communication method in which a terminal device receives a first synchronization signal block from a first access network device at a first frequency point, and receives a second synchronization signal block from a second access network device at a second frequency point, and then accesses the second access network device based on the second synchronization signal block. The first synchronization signal block includes information about the second frequency point, and the second frequency point is different from the first frequency point, with the search priority of the first frequency point being higher than that of the second frequency point.

[0101] In the above technical solution, the first frequency point and the second frequency point are different, and the search priority of the first frequency point is higher than that of the second frequency point. Therefore, the terminal device can first search for the first synchronization signal block on the first frequency point with higher search priority, and the first synchronization signal block can provide the terminal device with information about the second frequency point. In other words, the terminal device can quickly and easily determine the second frequency point based on the first synchronization signal block, reducing the time for the terminal device to determine the second frequency point. Furthermore, the terminal device can directly receive the second synchronization signal block on the second frequency point and access the second access network device, simplifying the complexity of the terminal device searching for the second synchronization signal block, improving the efficiency of the terminal device searching for the second synchronization signal block, and reducing the access latency of the terminal device.

[0102] Furthermore, this application also provides a communication method in which, when both the first access network device and the second access network device transmit synchronization signal blocks on a first frequency point, the first access network device can indicate the time domain resources of the second synchronization signal block to the terminal device through the first synchronization signal block. The time domain resources of the second synchronization signal block are different from those of the first synchronization signal block, thereby instructing the terminal device to receive the second synchronization signal block on the time domain resources and the first frequency point of the second synchronization signal block and access the second access network device. This simplifies the complexity of the terminal device searching for the second synchronization signal block, improves the efficiency of the terminal device searching for the second synchronization signal block, and reduces the access latency of the terminal device.

[0103] The technical solutions of this application embodiment can be used in various communication systems, including third-generation partnership project (3GPP) communication systems, such as fourth-generation (4G) systems like long-term evolution (LTE), 5G systems like new radio (NR), LTE and 5G hybrid networking systems, non-terrestrial networks (NTN), or other next-generation communication systems. The communication system can also be a non-3GPP communication system; there is no limitation on this.

[0104] The communication systems described above are merely illustrative examples, and are not limited to those described herein. The communication systems provided in this application do not impose any limitations on the solutions described herein. This will be explained uniformly here and will not be repeated below.

[0105] Figure 1 illustrates a possible, non-limiting system diagram. As shown in Figure 1, the communication system includes a radio access network (RAN) 100 and a core network (CN) 200. RAN 100 includes at least one access network device (110a and 110b in Figure 1, collectively referred to as 110) and at least one terminal device (120a-120j in Figure 1, collectively referred to as 120). RAN 100 may also include other access network devices, such as wireless relay devices and / or wireless backhaul devices (not shown in Figure 1). Terminal device 120 is wirelessly connected to access network device 110. Access network device 110 is wirelessly or wired connected to core network 200. The core network device in core network 200 and access network device 110 in RAN 100 can be different physical devices, or they can be the same physical device integrating core network logical functions and radio access network logical functions.

[0106] RAN 100 can be a 3GPP-related cellular system, such as a 4G, 5G mobile communication system, or a future-oriented evolution system. RAN 100 can also be an open access network (O-RAN or ORAN), a cloud radio access network (CRAN), or a wireless fidelity (WiFi) system. RAN 100 can also be a communication system that integrates two or more of the above systems.

[0107] Access network device 110, sometimes referred to as RAN entity or access node, constitutes part of the communication system and assists terminal devices in achieving wireless access. Multiple access network devices 110 in the communication system can be nodes of the same type or different types. In some scenarios, the roles of access network device 110 and terminal device 120 are relative. For example, network element 120i in Figure 1 can be a helicopter or drone, which can be configured as a mobile base station. For terminal devices 120j accessing RAN 100 through network element 120i, network element 120i is a base station; however, for base station 110a, network element 120i is a terminal device. Access network device 110 and terminal device 120 are sometimes both referred to as communication devices. For example, network elements 110a and 110b in Figure 1 can be understood as communication devices with base station functions, and network elements 120a-120j can be understood as communication devices with terminal device functions.

[0108] In one possible scenario, the access network device can be a satellite, base station, evolved NodeB (eNodeB), access point (AP), transmission reception point (TRP), next-generation NodeB (gNB), next-generation base station in future communication networks, base station in future mobile communication systems, or access node in a WiFi system. The access network device can be a macro base station (as shown in Figure 1, 110a), a micro base station or indoor station (as shown in Figure 1, 110b), a relay node or donor node, or a radio controller in a CRAN scenario. Optionally, the access network device can also be a server, wearable device, vehicle, or in-vehicle equipment. For example, the access network device in vehicle-to-everything (V2X) technology can be a roadside unit (RSU). All or part of the functions of the access network device in this application can also be implemented through software functions running on hardware, or through virtualization functions instantiated on a platform (e.g., a cloud platform). The access network device in this application may also be a logical node, logical module, or software that can implement all or part of the functions of the access network device.

[0109] In another possible scenario, multiple RAN nodes collaborate to assist terminal devices in achieving wireless access, with different RAN nodes each implementing a portion of the base station's functions. For example, RAN nodes can be central units (CUs), distributed units (DUs), CU-control plane (CPs), CU-user plane (UPs), or radio units (RUs), etc. CUs and DUs can be set up separately or included in the same network element, such as a baseband unit (BBU). RUs can be included in radio frequency equipment or radio frequency units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs).

[0110] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

[0111] Terminal devices can also be called user equipment (UE), mobile stations, mobile terminal devices, etc. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), V2X communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, smart cities, etc. Terminal devices can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, etc. The embodiments of this application do not limit the device form of the terminal device.

[0112] Based on the description of the communication system architecture shown in Figure 1, the method provided in this application embodiment can also be applied to NTN communication systems. In this application embodiment, the NTN communication system is taken as an example of a satellite communication system.

[0113] Figure 2(a) shows a schematic diagram of the architecture of a satellite communication system provided in this application. As shown in Figure 2(a), in this communication system, terminal devices access the network via an air interface. Access network equipment can be deployed on the ground, and the satellite is connected to the ground station via a wireless link. The access network equipment is connected to the ground station. The ground station and the ground access network equipment are connected to the core network via wired or wireless means. The satellite acts as a relay (i.e., the satellite has transparent relay capabilities, acting as a transparent relay node), used to forward signaling and data between the terminal devices and the ground station and ground access network equipment. The ground access network equipment mainly provides wireless access services, allocates wireless resources to the accessing terminal devices, and provides reliable wireless transmission protocols and data encryption protocols. The ground station and the ground access network equipment are responsible for forwarding signaling and data between the terminal devices and the core network.

[0114] If the satellite acts as a transparent node, that is, the satellite has a transparent transmission and forwarding function.

[0115] In the communication system shown in Figure 2(a), the core network provides services such as user access control, mobility management, session management, user security authentication, and billing. The core network comprises multiple functional units, which can be specifically divided into control plane functional entities and data plane functional entities. For example, control plane functional entities include the access and mobility management function (AMF) and the session management function (SMF). The AMF is responsible for user access management, security authentication, mobility management, etc. Data plane functional entities include the user plane function (UPF) unit and the data network. The UPF is responsible for managing user plane data transmission, traffic statistics, and other functions.

[0116] Figure 2(b) shows a schematic diagram of another satellite communication system architecture provided in this application. As shown in Figure 2(b), the communication system includes access network device 1, access network device 2, terminal device 1, and terminal device 2. Access network device 1 and access network device 2 are deployed on a satellite. Access network device 1 and access network device 2 can be connected via an Xn interface (corresponding to the NR system) or an X2 interface (corresponding to the LTE system), and can perform signaling interaction and user data transmission between them. In this communication system, some or all of the functions of the access network devices are deployed on the satellite. The terminal device establishes a communication connection with the access network device to enable the terminal device to access the network. The access network device and the terminal device complete the interaction of signaling and data. The access network device is connected to the core network through a ground station, wherein the access network device is connected to the ground station through an NG interface (corresponding to the NR system) or an S1 interface (corresponding to the LTE system), and the ground station is connected to the core network via wired or wireless means.

[0117] In the communication system shown in Figure 2(b), the core network includes multiple functional units, which can be specifically divided into control plane functional entities and data plane functional entities. For example, the control plane functional entities include AMF and SMF. The data plane functional entities include UPF units and the data network. For a detailed description of the functions of these functional entities, please refer to the relevant introductions above; they will not be repeated here.

[0118] The following is a supplementary explanation of the various network elements and the interfaces between them in Figure 2:

[0119] Terminal devices: Mobile devices that support the New Radio interface, typically such as mobile phones and tablets. They can access satellite networks via the air interface and initiate services such as making calls and accessing the internet. For details, please refer to the description of terminal devices above.

[0120] Access network equipment: mainly provides wireless access services, allocates wireless resources to access terminals, and provides reliable wireless transmission protocols and data encryption protocols, etc.

[0121] Core Network: Handles services such as user access control, mobility management, session management, user security authentication, and billing. It consists of multiple functional units, which can be divided into control plane and data plane functional entities. Access and mobility management network elements are responsible for user access management and control, user security authentication, and mobility management. User plane network elements are responsible for managing user plane data transmission and traffic statistics. Session management network elements are primarily responsible for the control plane functions of terminal device session management.

[0122] Ground station: Responsible for forwarding signaling and service data between access network equipment and core network.

[0123] Air interface: The wireless link between terminal equipment and access network equipment.

[0124] Xn interface: The interface between 5G access network devices, mainly used for signaling interactions such as handover.

[0125] X2 interface: The interface between LTE access network devices and other access network devices, mainly used for signaling interaction such as handover.

[0126] NG interface: The interface between 5G access network equipment and 5G core network equipment. It mainly interacts with the non-access stratum (NAS) signaling of the core network and user service data.

[0127] S1 interface: The interface between LTE access network equipment and LTE core network, mainly used for exchanging core network NAS and other signaling, as well as user service data.

[0128] It is understood that the communication system described in the embodiments of this application is for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and does not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0129] The communication system involved in the embodiments of this application has been described above.

[0130] The communication method provided in this application will be described below with reference to the communication system shown in Figure 1, taking the interaction between the terminal device and the access network device as an example. It should be understood that in the following embodiments of this application, the message names, parameter names, or information names between the terminal device and the access network device are merely examples, and may be different in other embodiments. The method provided in this application does not specifically limit these names.

[0131] It is understood that in the embodiments of this application, the terminal device or access network device may execute some or all of the steps in the embodiments of this application. These steps or operations are merely examples, and the embodiments of this application may also perform other operations or variations thereof. Furthermore, the various steps may be executed in different orders as presented in the embodiments of this application, and it is not necessarily necessary to execute all the operations in the embodiments of this application.

[0132] It is understood that this application uses access network equipment and terminal equipment as examples to illustrate the execution of the interaction, but this application does not limit the execution subject of the interaction. For example, the method executed by the access network equipment in this application can also be executed by a module applied to the access network equipment (e.g., a chip, chip system, or processor), or by a logical node, logical module, or software that can implement all or part of the functions of the access network equipment; similarly, the method executed by the terminal equipment in this application can also be executed by a module applied to the terminal equipment (e.g., a chip, chip system, or processor), or by a logical node, logical module, or software that can implement all or part of the functions of the terminal equipment.

[0133] Furthermore, in this application, "sending information" can be understood as one device sending information to another device, or it can also be understood as one logical module within a device sending information to another logical module. For example, "access network device sending information" can be understood as an access network device sending information to another device (such as a terminal device), or it can be understood as logical module 1 (such as a processing module) in the access network device sending information to logical module 2 (such as a transceiver module) in the access network device.

[0134] In this application, "receiving information" can be understood as one device receiving information from another device, or it can also be understood as a logical module within a device receiving information from another logical module. For example, "terminal device receiving information" can be understood as a terminal device receiving information from another device (such as an access network device), or it can be understood as logical module 1 (such as a processing module) in the terminal device receiving information from logical module 2 (such as a transceiver module) in the terminal device.

[0135] In this application, the phrase "sending information to... (e.g., a terminal device)" or the related illustrations in the accompanying drawings can be understood as the destination of the information being the terminal device. This can include sending information directly or indirectly to the terminal device. Similarly, the phrases "receiving information from... (e.g., an access network device)," "receiving information from... (e.g., an access network device)," or "receiving information sent (e.g., by an access network device)," or the related illustrations in the accompanying drawings, can be understood as the source of the information being the access network device. This can include receiving information directly or indirectly from the access network device. Information may undergo necessary processing between the source and destination, such as format changes, but the destination can understand the valid information from the source. Similar expressions in this application can be interpreted similarly, and will not be elaborated further here.

[0136] Referring to Figure 3, which is a flowchart of a communication method provided in an embodiment of this application, the method may include the following steps S301-S304.

[0137] S301, The first access network device determines the first synchronization signal block.

[0138] The first synchronization signal block includes information about the second frequency point. The second frequency point is used by the terminal device to receive the second synchronization signal block, and the second synchronization signal block is used by the terminal device to access the second access network device.

[0139] For example, the first access network device can be any one of the at least one access network device 110 in the communication system shown in FIG1, or any one of the satellite transparent forwarding node, access network device 1, or access network device 2 in the communication system shown in FIG2; the second access network device can be any one of the at least one access network device 110 in the communication system, or any one of the satellite transparent forwarding node, access network device 1, or access network device 2 in the communication system shown in FIG2; the terminal device can be any one of the at least one terminal device 120 in the communication system shown in FIG1, or any one of the terminal device, terminal device 1, or terminal device 2 in the communication system shown in FIG2.

[0140] Optionally, the first synchronization signal block may include one or more of the following: primary synchronization signal, secondary synchronization signal, or other synchronization information, such as system frame number, etc. This application does not limit the information that may be included in the first synchronization signal block.

[0141] In this application, the first access network device and the second access network device are different. When this application is used in a satellite communication system, the first access network device can be a first satellite, and the second access network device can be a second satellite, with the altitude of the first satellite's orbit being greater than or equal to the altitude of the second satellite's orbit. For example, corresponding to the first satellite's orbit being greater than the second satellite's orbit, if the second satellite is located in a low Earth orbit (LEO), then the first satellite can be located in an orbit with an altitude higher than the LEO altitude. For example, the first satellite can be located in a geostationary Earth orbit (GEO), a medium Earth orbit (MEO), or a highly elliptical orbit (HEO). This application does not impose any restrictions on this.

[0142] Optionally, the first synchronization signal block can be NCD-SSB, and the second synchronization signal block can be CD-SSB.

[0143] In some embodiments, the information of the second frequency point includes one or more of the following: a first subcarrier offset (e.g., a first Kssb) or first information (e.g., pdcch-ConfigSIB1). The first information indicates the second frequency point; the first subcarrier offset is related to one or more of the following: the synchronization signal block grid corresponding to the second frequency point, and the frequency band to which the second frequency point belongs. The first Kssb and pdcch-ConfigSIB1 can be parameters indicated in the main information block. The frequency band to which the second frequency point belongs is one of the FR1 and FR2 bands. The synchronization signal block grid corresponding to the second frequency point is a preset synchronization signal block grid or one of other grids besides the preset synchronization signal block grid; the preset synchronization signal block grid can be understood as the synchronization signal block grid defined in the protocol.

[0144] To clarify, the first subcarrier offset is related to the synchronization signal block grid corresponding to the second frequency point, or it can be understood as being related to whether the second frequency point is located within a preset synchronization signal block grid. Specifically, if the synchronization signal block grid corresponding to the second frequency point is a preset synchronization signal block grid, or if the second frequency point is located within a preset synchronization signal block grid, the value range of the first subcarrier offset can be determined to be 24–29 and 12–13. If the synchronization signal block grid corresponding to the second frequency point is one of the other grids besides the preset synchronization signal block grid, or if the second frequency point is not located within a preset synchronization signal block grid, the value range of the first subcarrier offset can be determined to be 30–31 and 14–15.

[0145] The first subcarrier offset is related to the frequency band to which the second frequency point belongs. This can be understood as the range of values ​​for the first subcarrier offset differing depending on the frequency band to which the second frequency point belongs. Specifically, when the frequency band corresponding to the second frequency point is FR1, the range of values ​​for the first subcarrier offset is 24–29 and 30–31; when the frequency band corresponding to the second frequency point is FR2, the range of values ​​for the first subcarrier offset is 12–13 and 14–15.

[0146] In one possible implementation, the process of S301 includes: the first access network device adding information about the second frequency point to the first synchronization signal block based on the second frequency point. Since the first access network device has a larger coverage area—for example, larger than the coverage area of ​​the second access network device—it can cover the area where the terminal device is located. Therefore, the first access network device can determine the access network device (e.g., the second access network device) providing access services for the terminal device and add the second frequency point information to the first synchronization signal block, so that the terminal device can determine the second frequency point based on the received second frequency point information. In this way, the terminal device does not need to search for the second synchronization signal on multiple frequency points, greatly shortening the time required for the terminal device to search for the second synchronization signal and improving efficiency.

[0147] Optionally, for the different first and second frequency points, the specific description of the information of the second frequency point in the first synchronization signal block can be referred to in the following embodiments 1-3, which will not be repeated here.

[0148] S302. The first access network device transmits a first synchronization signal block on a first frequency. Correspondingly, the terminal device receives the first synchronization signal block from the first access network device on the first frequency.

[0149] The second frequency point is different from the first frequency point, and the search priority of the first frequency point is greater than that of the second frequency point.

[0150] Optionally, both the first frequency point and the second frequency point can be frequencies within the first synchronization signal block grid. The protocol can configure the search priority of the frequencies within the first synchronization signal block grid, allowing the terminal device to determine the frequency point to search first.

[0151] Alternatively, the first frequency point can be a frequency point in the second synchronization signal block grid, and the second frequency point can be a frequency point in the third synchronization signal block grid. The protocol can define multiple synchronization signal block grids and their corresponding search priorities, allowing the terminal device to determine which synchronization signal block grid's frequency point to search first. These multiple synchronization signal block grids can include the second and third synchronization signal block grids. For example, the protocol can configure the search priority of frequencies in the second synchronization signal block grid to be higher than that of frequencies in the third synchronization signal block grid, thus making the search priority of the first frequency point in the second synchronization signal block grid higher than that of the second frequency point in the third synchronization signal block grid. This application does not limit the method of configuring the search priority of the first and second frequency points.

[0152] In one possible implementation, based on the search priority of the first frequency point and the search priority of the second frequency point, the terminal device can search for a synchronization signal block on the first frequency point with the highest search priority, and then receive the first synchronization signal block from the first access network device.

[0153] In this case, the terminal device can further determine the second frequency point based on the information of the second frequency point in the first synchronization signal block. For specific implementation schemes of determining the second frequency point based on the information of the second frequency point, corresponding to the difference between the first and second frequency points, please refer to Embodiments 1-3 below, which will not be repeated here.

[0154] S303. The second access network device transmits a second synchronization signal block on the second frequency. Correspondingly, the terminal device receives the second synchronization signal block from the second access network device on the second frequency.

[0155] In one possible implementation, the second access network device can generate a second synchronization signal block based on the system clock and configuration parameters. The second access network device then transmits the second synchronization signal block on a second frequency point, according to a preset power and beam direction, to ensure that terminal devices within the coverage area can receive the second synchronization signal block.

[0156] Accordingly, the terminal device searches on the second frequency point based on a preset search strategy, and can then receive the second synchronization signal block from the second access network device. The preset search strategy may or may not include information such as frequency intervals and / or time windows; this application does not impose any restrictions on this.

[0157] The second synchronization signal block may contain one or more of the following: main information block, main synchronization signal, auxiliary synchronization signal, or other synchronization information, such as system frame number. This application does not limit the information that the second synchronization signal block may contain.

[0158] S304. The terminal device connects to the second access network device based on the second synchronization signal block.

[0159] In one possible implementation, the terminal device can obtain information such as the frequency and phase of the signal from the second access network device based on the second synchronization signal block, and then control the terminal device's receiving frequency and transmitting frequency to be consistent with the receiving frequency and transmitting frequency of the second access network device, thereby achieving time and frequency synchronization.

[0160] Optionally, the second access network device can further encode and modulate a system information block including its configuration information and cell access parameters, and broadcast it according to a broadcast strategy (e.g., a preset period). Correspondingly, the terminal device can receive the system information block (SIB), such as SIB1, on the corresponding channel and time based on the information from the system information block included in the second synchronization signal block, to obtain the configuration information and cell access parameters of the second access network device, preparing for subsequent cell access. The broadcast of the system information block and the transmission of the second synchronization signal block are correlated and coordinated in time and frequency so that the terminal device can obtain system information after receiving the second synchronization signal block.

[0161] Furthermore, the terminal device can complete random access based on system information. Then, after completing random access, the terminal device can send a Radio Resource Control (RRC) connection request message to the second access network device to request the establishment of an RRC connection. The second access network device can receive the RRC connection request message from the terminal device and, based on factors such as network resource availability and the terminal device's access permissions, decide whether to accept the connection request. If accepted, it sends an RRC connection establishment message to the terminal device, allocates radio resources for the terminal device, configures relevant communication parameters, and assists the terminal device in completing access.

[0162] In the above technical solution, the first frequency point and the second frequency point are different, and the search priority of the first frequency point is higher than that of the second frequency point. Therefore, the terminal device can first search for the first synchronization signal block on the first frequency point with higher search priority, and the first synchronization signal block can provide the terminal device with information about the second frequency point. In other words, the terminal device can quickly and easily determine the second frequency point based on the first synchronization signal block, reducing the time for the terminal device to determine the second frequency point. Furthermore, the terminal device can directly receive the second synchronization signal block on the second frequency point and access the second access network device, simplifying the complexity of the terminal device searching for the second synchronization signal block, improving the efficiency of the terminal device searching for the second synchronization signal block, and reducing the access latency of the terminal device.

[0163] Furthermore, when the first access network device is the first satellite and the second access network device is the second satellite, and the orbital altitude of the first satellite is greater than that of the second satellite, although the first satellite has a higher orbital altitude and a poorer link budget, its coverage area is larger. For example, when the first satellite detects that the second satellite can cover or is about to cover the area where the terminal device is located, the first satellite can provide the terminal device with information on a second frequency point to assist the terminal device in accessing the satellite and reduce the access latency of the terminal device.

[0164] When the first access network device is the first satellite and the second access network device is the second satellite, and the orbital altitude of the first satellite is equal to that of the second satellite, the first satellite can also provide the terminal device with information on a second frequency point when it detects that the second satellite can cover or is about to cover the area where the terminal device is located. This assists the terminal device in accessing the second satellite and reduces the access latency of the terminal device.

[0165] The following, in conjunction with the information of the second frequency point in S301, through Examples 1-3, specifically explains the information of the second frequency point and the scheme by which the terminal device determines the second frequency point based on the information of the second frequency point when the first frequency point and the second frequency point are different.

[0166] Example 1:

[0167] As one possible embodiment provided in this application, the information of the second frequency point includes a first subcarrier offset and first information. The first access network device can indicate the offset of the second frequency point relative to the first frequency point using the first subcarrier offset and the first information. Then, the terminal device can determine the offset of the second frequency point relative to the first frequency point using the first subcarrier offset and the first information, and determine the second frequency point based on this offset. Specifically, the implementation scheme for the terminal device to determine the second frequency point based on the information of the second frequency point provided in Embodiment 1 may include the following scheme 1 or scheme 2.

[0168] Option 1:

[0169] In one possible implementation, the information of the second frequency point includes a first subcarrier offset that is a value between 24 and 29 or between 12 and 13. For an explanation of the range of the first subcarrier offset (i.e., 24 to 29 or 12 to 13), please refer to the explanations of Tables 2 and 3 in the aforementioned related technologies; they will not be repeated here.

[0170] For example, if the frequency interval between the second frequency point and the first frequency point is less than or equal to a preset threshold, and the second frequency point is located within a preset synchronization signal block grid, the information of the second frequency point includes a first subcarrier offset that is a value between 24 and 29 or 12 and 13. The preset threshold can be defined in the protocol, for example, equal to 50 MHz.

[0171] Optionally, the information of the second frequency point may include a first parameter (e.g., control resource set 0 (controlResourceSetZero)) and a second parameter (e.g., searchspaceZero)). In this case, based on the first and second parameters, the index of the offset of the second frequency point relative to the first frequency point (i.e., pdcch-ConfigSIB1) can be determined; and then, based on the index and the first subcarrier offset, the offset of the second frequency point relative to the first frequency point can be determined.

[0172] For details regarding the control resource set 0 and search space 0, please refer to "III. Synchronization Signal Block" in the relevant technology; it will not be repeated here.

[0173] For example, the first parameter, the second parameter, and the index of the second frequency point relative to the first frequency point can satisfy the following relationship: Index of the second frequency point relative to the first frequency point = a × First parameter + Second parameter (Formula 2)

[0174] Where 'a' is a positive integer, such as 16. The specific value of 'a' can be determined according to the actual situation, and this application does not impose any restrictions on it.

[0175] Based on the information of the second frequency point mentioned above, in one possible implementation, the terminal device can determine the index of the offset of the second frequency point relative to the first frequency point based on Formula 2, using the first parameter and the second parameter included in the first information; then, based on the first subcarrier offset (e.g., 24) and the index of the second frequency point relative to the first frequency point, the offset of the second frequency point relative to the first frequency point is determined. For example, the correspondence between the first subcarrier offset, the index of the second frequency point relative to the first frequency point, and the offset of the second frequency point relative to the first frequency point can be pre-configured or defined in the protocol. The terminal device can determine the offset of the second frequency point relative to the first frequency point based on the above correspondence, the first subcarrier offset, and the index of the second frequency point relative to the first frequency point.

[0176] Table 4

[0177] Table 5

[0178] It is understandable that, in Table 4 above, when the value range of Kssb is 24 to 31, the corresponding pdcch-ConfigSIB1 and the number of units of offset are shown. When the value of Kssb is in the range of 24 to 31, the pdcch-ConfigSIB1 corresponding to Kssb is used to indicate the index of the offset of the second frequency point in the FR1 band relative to the first frequency point, and the number of units of the offset corresponding to Kssb. Used to indicate the offset of the second frequency point in the FR1 band relative to the first frequency point.

[0179] Table 5 above includes the pdcch-ConfigSIB1 and the number of offset units for each Kssb when the value range is 12 to 15. When the value of Kssb is in the range of 12 to 15, the pdcch-ConfigSIB1 corresponding to Kssb is used to indicate the index of the offset of the second frequency point in the FR2 band relative to the first frequency point, and the number of units of the offset corresponding to Kssb. Used to indicate the offset of the second frequency point in the FR2 band relative to the first frequency point.

[0180] In one example, taking Table 4 as an example, if the offset of the first subcarrier is 24 and the index of the offset of the second frequency point relative to the first frequency point is 255, then referring to the first row of Table 4 above, the offset of the second frequency point relative to the first frequency point is determined as follows. The 256th value in the column, that is, the offset of the second frequency point relative to the first frequency point, is 256.

[0181] Optional, It can also indicate the scaling factor or correction value corresponding to the offset of the second frequency point relative to the first frequency point. Specifically, the offset of the second frequency point relative to the first frequency point can be determined by processing the scaling factor with a preset offset parameter (e.g., multiplication). For example, using... Taking the scaling factor as n and the preset offset parameter as δf as an example, the offset of the second frequency point relative to the first frequency point can satisfy the following relationship: the offset of the second frequency point relative to the first frequency point = n*δf.

[0182] Alternatively, the offset of the second frequency point relative to the first frequency point can be determined by performing data processing (e.g., addition) on the correction value and the preset offset parameter. For example, taking the preset offset parameter as δf, the offset of the second frequency point relative to the first frequency point can satisfy the following relationship: the offset of the second frequency point relative to the first frequency point...

[0183] For example, the terminal device can determine a preset offset parameter based on a predefined protocol, and then, in conjunction with... The indicated scaling factor or correction value determines the offset of the second frequency point relative to the first frequency point. Compared to the data volume of the offset of the second frequency point relative to the first frequency point, the data volume of the scaling factor and correction value is smaller; therefore, Indicating scaling factors or correction values ​​can reduce resource overhead.

[0184] Subsequently, the terminal device can determine the second frequency point based on the offset of the second frequency point relative to the first frequency point, the first frequency point, and the unit size of the offset. For details, please refer to the relevant explanation in "III. Synchronization Signal Block" of the aforementioned related technologies; it will not be repeated here.

[0185] To further explain, based on the above scheme 1, the terminal device can determine whether the first frequency point can be accessed based on the value of the first subcarrier offset. For example, when the value of the first subcarrier offset is 24, the terminal device can determine that the type of the first synchronization signal block is NCD-SSB, and thus determine that the first frequency point is not used for access.

[0186] Option 2:

[0187] In one possible implementation, the first subcarrier offset is any value outside the range of occupied subcarrier offsets. For example, as shown in Tables 4 and 5 below, the range of occupied subcarrier offsets could include 24 <= subcarrier offset <= 29 and 12 <= subcarrier offset <= 13.

[0188] For example, if the first access network device is not located in the preset synchronization signal block grid at the second frequency point, the first subcarrier offset is any one outside the range of occupied subcarrier offsets.

[0189] In one example, the first subcarrier offset is either 30 or 31, or either 14 or 15. Specifically, if the frequency value corresponding to the second frequency point is within the first frequency range (corresponding to the FR1 band), then the first subcarrier offset is determined to be either 30 or 31; if the frequency value corresponding to the second frequency point is within the second frequency range (corresponding to the FR2 band), then the first subcarrier offset is determined to be either 14 or 15. Of course, the above is an exemplary description of the first subcarrier offset, and this application does not limit the specific value of the first subcarrier offset.

[0190] Based on the information about the second frequency point, in one possible implementation, the terminal device can determine the index of the offset of the second frequency point relative to the first frequency point based on Formula 2, using the first and second parameters included in the first information; then, based on the first subcarrier offset (e.g., 14) and the index of the second frequency point relative to the first frequency point, it can determine the offset of the second frequency point relative to the first frequency point. For example, the correspondence between the first subcarrier offset, the index of the second frequency point relative to the first frequency point, and the offset of the second frequency point relative to the first frequency point can be pre-configured or defined in the protocol. The terminal device can then determine the offset of the second frequency point relative to the first frequency point based on the aforementioned correspondence, the first subcarrier offset, and the index of the second frequency point relative to the first frequency point.

[0191] In one example, taking Table 5 as an example, if the offset of the first subcarrier is 14 and the index of the offset of the second frequency point relative to the first frequency point is 0, then referring to the third row of Table 5 above, the offset of the second frequency point relative to the first frequency point is determined as follows. The first value in the column, that is, the offset of the second frequency point relative to the first frequency point, is offset513.

[0192] Subsequently, the terminal device can determine the implementation method of the second frequency point based on the offset of the second frequency point relative to the first frequency point, the first frequency point, and the unit size of the offset. Refer to the relevant description in "III. Synchronization Signal Block" in the above-mentioned related technologies, which will not be repeated here.

[0193] In the above embodiments, a second frequency point can be flexibly indicated without introducing additional broadcast messages and the overhead of the common control channel, thereby reducing the resource overhead on the first frequency point.

[0194] Example 2:

[0195] As one possible embodiment of this application, when the first frequency point and the second frequency point are different, the information of the second frequency point includes the first information. The first access network device can use the first information to indicate the second frequency point or the offset of the second frequency point relative to the first frequency point.

[0196] Optionally, the first information may be included in pdcch-ConfigSIB1 indicated by the main information block, or other information that the first synchronization signal block may carry or may include, and this application does not limit this.

[0197] Understandably, regarding the functionality of pdcch-ConfigSIB1, when the first information is included in pdcch-ConfigSIB1, pdcch-ConfigSIB1 can be used to indicate the time-frequency resources of a common control signal, and this common control signal can be used to schedule broadcast messages. Alternatively, when the first information is included in pdcch-ConfigSIB1, pdcch-ConfigSIB1 may not be used to indicate the time-frequency resources of a common control signal. This application does not limit whether pdcch-ConfigSIB1 can also be used to indicate the time-frequency resources of a common control signal when the first information is included in pdcch-ConfigSIB1.

[0198] In the case that pdcch-ConfigSIB1 includes the first information, to prevent the first type of terminal device from misinterpreting the information indicated by pdcch-ConfigSIB1, the first synchronization signal block also includes second indication information (e.g., information carried in the main information block). The second indication information instructs the first type of terminal device to prohibit access to the first frequency point. The first type of terminal device is one that does not have the ability to interpret the first information included in pdcch-ConfigSIB1; that is, the first type of terminal device cannot determine the second frequency point based on the first information.

[0199] It should be understood that the first type of terminal device can determine that access to the first frequency point is prohibited based on the content indicated by the second indication information, and the second type of terminal device (that is, the terminal device that can interpret the information indicated by pdcch-ConfigSIB1 when pdcch-ConfigSIB1 is used to indicate the second frequency point) can determine the second frequency point through pdcch-ConfigSIB1.

[0200] Optionally, the first information may include a second frequency point or an offset of the second frequency point relative to the first frequency point. Based on the first information including the information of the second frequency point, in one example, if the first information contains the second frequency point, the terminal device can directly parse the first information to determine the second frequency point; in another example, if the first information contains an offset of the second frequency point relative to the first frequency point, the terminal device can determine the second frequency point based on the offset of the second frequency point relative to the first frequency point, combined with the first frequency point and the unit size of the offset.

[0201] Optionally, in one possible implementation, the first information is used to schedule the second information, which indicates a second frequency point. For example, the first information can indicate the time-domain and frequency-domain resources of the second information, so that the terminal device can receive the second information in the time and frequency-domain resource bands indicated by the time-domain resources. The second information can directly indicate the second frequency point, or it can indicate the offset of the second frequency point relative to the first frequency point; this application does not impose any limitations on this.

[0202] Understandably, when the information capacity of the first information is less than the preset capacity (for example, the information capacity of the first information is 8 bits), the information of the second frequency point can be stored in the second information, and the function of the first information can be configured to schedule the second information, thereby achieving the purpose of indicating the second frequency point to the terminal device.

[0203] Furthermore, optionally, in addition to including the first information, the information of the second frequency point may also include at least one of the following: first indication information and satellite ephemeris of the second access network device. Example 1 illustrates a scheme where the information of the second frequency point also includes the first indication information, and Example 2 illustrates a scheme where the information of the second frequency point also includes the satellite ephemeris of the second access network device.

[0204] Of course, the information for the second frequency point also includes the first indication information and the satellite ephemeris scheme of the second access network device, which can be referred to in conjunction with the following examples 1 and 2. This application will not elaborate on this.

[0205] Example 1:

[0206] In one possible implementation, in addition to the first information, the information of the second frequency point may further include first indication information. The first indication information is used to indicate that the first information is used to indicate the second frequency point.

[0207] Optionally, the first indication information can be a subcarrier offset, in which case the subcarrier offset can be used to indicate that the first information is used to indicate the second frequency point. The subcarrier offset can be any subcarrier offset outside the range of already occupied subcarrier offsets. For example, if the frequency band corresponding to the second frequency point is FR1, the subcarrier offset can be 30 or 31; or if the frequency band corresponding to the second frequency point is FR2, the subcarrier offset can be 14 or 15.

[0208] It should be understood that the terminal device can determine the second frequency point by using the first indication information included in the information of the second frequency point. In other words, the first indication information can instruct the terminal device to directly determine the second frequency point by using the first information, without needing to perform the process of determining the second frequency point offset in Embodiment 1, thus providing clear indication information for the method by which the terminal device determines the second frequency point.

[0209] Optionally, the first indication information can also be used to instruct the first type of terminal device to prohibit access to the first frequency point. For the first type of terminal device, based on the first indication information, it can be determined that the first synchronization signal block is not a synchronization signal block used for access operation, therefore the first type of terminal device will not have an access operation.

[0210] Example 2:

[0211] In one possible implementation, the second access network device is a second satellite, and in addition to the first information, the information of the second frequency point may also include the satellite ephemeris of the second access network device.

[0212] Understandably, the aforementioned satellite ephemeris can include information about the second satellite's position, velocity, and other operational status changes over time. In other words, based on the satellite ephemeris, the terminal device can determine the first time the second satellite covers the area where it is located. Consequently, the terminal device can determine when to receive the second synchronization signal block from the second satellite at the first time and on the second frequency. This eliminates the need for the terminal device to continuously search for the second synchronization signal block on the second frequency; a search can be performed at the first time, thus improving the reliability of the terminal device's reception of the second synchronization signal block.

[0213] In the above technical solution, although the resource overhead of the first information is increased, the terminal device can determine the second frequency point through the first information without having to calculate the second frequency point, thus simplifying the complexity of the terminal device in determining the second frequency point.

[0214] Example 3:

[0215] As one possible embodiment of this application, the first synchronization signal block includes information about a second frequency point and second indication information. When the first frequency point and the second frequency point are different, the information about the second frequency point includes a first subcarrier offset and first information. The second indication information is used to indicate that access to the first frequency point is prohibited. The range of the first subcarrier offset in Embodiment 3 may differ from that in Embodiment 1.

[0216] In one possible implementation, the terminal device can determine that access to the first frequency point is prohibited by the second indication information, and indicate the offset of the second frequency point relative to the first frequency point by the first subcarrier offset and the first information, and then determine the second frequency point based on the offset.

[0217] Optionally, the first subcarrier offset can be any one of 1-31. Accordingly, the subcarrier offsets in 1-31 are redefined, and the value of any subcarrier offset in the redefined range of 1-31 does not indicate whether the type of the corresponding synchronization signal block is NCD-SSB.

[0218] Understandably, in Embodiment 3, since the first synchronization signal block contains second indication information for indicating that access to the first frequency point is prohibited, the terminal device does not need to determine whether the first frequency point can be accessed based on the value of the first subcarrier offset. That is, the range of the first subcarrier offset is not limited to 24–29, 12–13, 30–31, or 14–15. Therefore, the above technical solution expands the range of the first subcarrier offset to indicate a larger number of frequency points.

[0219] In some embodiments, the information of the second frequency point in this application may also include the first subcarrier offset, but not the first information. In this case, the terminal device can determine the second frequency point according to pre-configured rules or rules defined in the protocol, such as the correspondence between the first subcarrier offset and the second frequency point, or the correspondence between the first subcarrier offset and the second frequency point offset relative to the first frequency point.

[0220] The above describes a communication method provided by this application when the first frequency point and the second frequency point are different. Below, another communication method provided by this application will be described when the first frequency point and the second frequency point are the same.

[0221] Referring to Figure 4, which is a flowchart of another communication method provided in an embodiment of this application, the method may include the following S401-S404.

[0222] S401, The first access network device determines the first synchronization signal block.

[0223] The first synchronization signal block is used to indicate the time-domain resources of the second synchronization signal block. The time-domain resources of the second synchronization signal block are different from those of the first synchronization signal block; the time-domain resources of the second synchronization signal block are used by the terminal device to receive the second synchronization signal block on the first frequency point; the second synchronization signal block is used by the terminal device to access the second access network device. The first access network device can be any one of at least one access network device 110 in the communication system shown in Figure 1, or any one of the satellite transparent forwarding node, access network device 1, or access network device 2 in the communication system shown in Figure 2; the second access network device can be any one of at least one access network device 110 in the communication system, or any one of the satellite transparent forwarding node, access network device 1, or access network device 2 in the communication system shown in Figure 2; the terminal device can be any one of at least one terminal device 120 in the communication system shown in Figure 1, or any one of the terminal device, terminal device 1, or terminal device 2 in the communication system shown in Figure 2.

[0224] It is understood that this application does not limit the way in which the first synchronization signal block indicates the time-domain resources of the second synchronization signal block. Optionally, the way in which the first synchronization signal block indicates the time-domain resources of the second synchronization signal block may include the following methods 1-3:

[0225] Method 1: The first synchronization signal block contains fourth information, which can indicate the time-domain resources of the second synchronization signal block. For example, the fourth information is contained in the main information block, such as pdcch-ConfigSIB1.

[0226] Method 2: The first synchronization signal block can be used to schedule the third information, which indicates the time domain resources of the second synchronization signal block.

[0227] Understandably, in Method 2, the time domain resources of the second synchronization signal block are not limited by the amount of data in the first synchronization signal block. The time domain resources of the second synchronization signal block can be indicated by third information (i.e., more data), thus realizing a more flexible time domain resource indication method.

[0228] Method 3: The first synchronization signal block contains fourth information, which is used to schedule the third information. The third information indicates the time-domain resources of the second synchronization signal block. For example, the fourth information is contained in the main information block, such as pdcch-ConfigSIB1.

[0229] Optionally, the fourth information may indicate the time-domain and frequency-domain resources of the third information, so that the terminal device can receive the third information in the time and frequency-domain resource bands indicated by the time-domain resources.

[0230] Understandably, when the frequency corresponding to the first synchronization signal block is the same as the frequency corresponding to the second synchronization signal block, or when their offset is less than a preset offset, to avoid interference caused by the simultaneous transmission of the first and second synchronization signal blocks, the first access network device transmits the first synchronization signal block and the second access network device transmits the second synchronization signal block in a time-division manner. When the frequency corresponding to the first and second synchronization signal blocks is the same as the frequency corresponding to the second synchronization signal block, or when their offset is less than a preset offset, the first access network device can transmit the first synchronization signal block, thereby reducing interference to the second synchronization signal block transmitted by the second access network device.

[0231] One possible implementation is that, when the first synchronization signal block indicates the time-domain resources of the second synchronization signal block, the first synchronization signal block can implicitly indicate that the frequency point corresponding to the first synchronization signal block is the same as the frequency point corresponding to the second synchronization signal block.

[0232] Another possible implementation is that the first synchronization signal block includes third indication information. This third indication information indicates that the frequency point corresponding to the first synchronization signal block is the same as the frequency point corresponding to the second synchronization signal block; that is, the frequency point for receiving the first synchronization signal block is the same as the frequency point for receiving the second synchronization signal block. It should be understood that, using the third indication information, it is possible to directly indicate that the frequency point corresponding to the first synchronization signal block is the same as the frequency point corresponding to the second synchronization signal block, so that the terminal device clearly understands that it can receive the second synchronization signal at the frequency point for receiving the first synchronization signal block.

[0233] Optionally, the aforementioned third indication information can be indicated in the form of at least 1 bit information, for example, using "1" or "true" to indicate that the frequency point corresponding to the first synchronization signal block is the same as the frequency point corresponding to the second synchronization signal block.

[0234] Optionally, the time-domain resources of the second synchronization signal block may include a time window or a time range of a timer for receiving the second synchronization signal block, and this application does not limit this. For example, as shown in Figure 5, the time window for receiving the second synchronization signal block can be a time range other than the time range corresponding to the first synchronization signal block. Within this time window, the terminal device can receive the second synchronization signal block. Alternatively, the time range of the timer may include the transmission time range corresponding to the second synchronization signal block and / or the transmission time range corresponding to the first synchronization signal block, wherein the transmission time range corresponding to the second synchronization signal block is different from the transmission time range corresponding to the first synchronization signal block. The terminal device can receive the second synchronization signal block within the transmission time range indicated by the timer.

[0235] It is understandable that when the offset between the frequency point corresponding to the first synchronization signal block and the frequency point corresponding to the second synchronization signal block is less than the preset offset, the first synchronization signal block can indicate the frequency point of the second synchronization signal block in addition to indicating the time domain resources of the second synchronization signal block, as shown in Figure 3.

[0236] Optionally, the first synchronization signal block may include one or more of the following: primary synchronization signal, secondary synchronization signal, or other synchronization information, such as system frame number, etc. This application does not limit the information that may also be included in the first synchronization signal block.

[0237] Optionally, for a detailed description of the first access network device and the second access network device, please refer to the description of the first access network device and the second access network device in the embodiment shown in S301, which will not be repeated here.

[0238] S402, the first access network device transmits a first synchronization signal block on a first frequency. Correspondingly, the terminal device receives the first synchronization signal block from the first access network device on the first frequency.

[0239] In one possible implementation, based on a predefined protocol, the search priority of the first frequency point corresponding to the first access network device can be set to be the highest. Then, the terminal device can search for the first synchronization signal block on the first frequency point with the highest search priority. When the first access network device transmits the first synchronization signal block on the first frequency point, the terminal device can receive the first synchronization signal block on the first frequency point. The first frequency point is the frequency point corresponding to the first synchronization signal block.

[0240] S403. The second access network device transmits the second synchronization signal block on the time domain resources of the first frequency point and the second synchronization signal block. Correspondingly, the terminal device receives the second synchronization signal block from the second access network device on the time domain resources of the first frequency point and the second synchronization signal block.

[0241] In one possible implementation, the second access network device can generate a second synchronization signal block based on the system clock and configuration parameters. The second access network device then transmits the second synchronization signal block at the first frequency and using the time domain resources of the second synchronization signal block, according to a preset power and beam direction, to ensure that terminal devices within the coverage area can receive the second synchronization signal block.

[0242] Accordingly, the terminal device searches on the first frequency point based on a preset search strategy, and can then receive the second synchronization signal block from the second access network device. The preset search strategy may or may not include information such as frequency intervals and / or time windows; this application does not impose any restrictions on this.

[0243] The second synchronization signal block may contain one or more of the following: primary synchronization signal, secondary synchronization signal, or other synchronization information, such as system frame number. This application does not limit the information that the second synchronization signal block may contain.

[0244] S404. The terminal device connects to the second access network device based on the second synchronization signal block.

[0245] Optionally, the specific implementation of S404 can be referred to the embodiment shown in S304 above, and will not be repeated here.

[0246] In the above technical solution, when both the first access network device and the second access network device transmit synchronization signal blocks on the first frequency point, the first access network device can indicate the time domain resources of the second synchronization signal block to the terminal device through the first synchronization signal block. The time domain resources of the second synchronization signal block are different from those of the first synchronization signal block. This instructs the terminal device to receive the second synchronization signal block on the time domain resources and the first frequency point of the second synchronization signal block and access the second access network device. This simplifies the complexity of the terminal device searching for the second synchronization signal block, improves the efficiency of the terminal device searching for the second synchronization signal block, and reduces the access latency of the terminal device.

[0247] The method provided in this application has been described above. In addition, this application also provides a communication device for implementing the functions described in the above method embodiments.

[0248] It is understood that, in order to achieve the aforementioned functions, the communication device includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily recognize that, based on the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0249] This application embodiment can divide the communication device into functional modules according to the above method embodiment. For example, each function can be divided into its own functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. It is understood that the module division in this application embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0250] Figure 6 shows a schematic diagram of a communication device 60. The communication device 60 includes a processing module 601 and a transceiver module 602. This communication device 60 can be used to implement the functions of the aforementioned terminal device or first access network device.

[0251] In some embodiments, the communication device 60 may further include a storage module (not shown in FIG. 6) for storing program instructions and data.

[0252] In some embodiments, the transceiver module 602, also referred to as a transceiver unit, is used to implement sending and / or receiving functions. The transceiver module 602 may consist of a transceiver circuit, a transceiver, a transceiver unit, or a communication interface.

[0253] In some embodiments, the transceiver module 602 may include a receiving module and a sending module, respectively configured to perform the receiving and sending steps performed by the terminal device or the first access network device in the above method embodiments, and / or other processes to support the technology described herein; the processing module 601 may be configured to perform the processing steps performed by the terminal device or the first access network device in the above method embodiments, and / or other processes to support the technology described herein.

[0254] When the communication device 60 is used to implement the functions of a terminal device:

[0255] In one possible implementation, the transceiver module 602 is configured to receive a first synchronization signal block from a first access network device at a first frequency point, the first synchronization signal block including information of a second frequency point; the second frequency point is different from the first frequency point, and the search priority of the first frequency point is greater than the search priority of the second frequency point; the transceiver module 602 is also configured to receive a second synchronization signal block from a second access network device at the second frequency point; the processing module 601 is configured to access the second access network device based on the second synchronization signal block.

[0256] or,

[0257] In another possible implementation, the transceiver module 602 is configured to receive a first synchronization signal block from the first access network device at a first frequency point, the first synchronization signal block being used to indicate the time domain resources of the second synchronization signal block; the time domain resources of the second synchronization signal block are different from the time domain resources of the first synchronization signal block; the transceiver module 602 is also configured to receive a second synchronization signal block from the second access network device at the first frequency point and on the time domain resources of the second synchronization signal block; the processing module 601 is configured to access the second access network device based on the second synchronization signal block.

[0258] When the communication device 60 is used to implement the functions of the first access network device:

[0259] In one possible implementation: a processing module 601 is used to determine a first synchronization signal block; a transceiver module 602 is used to transmit the first synchronization signal block on a first frequency point, the first synchronization signal block including information of a second frequency point, the second frequency point being different from the first frequency point, the search priority of the first frequency point being greater than the search priority of the second frequency point; the second frequency point is used for the terminal device to receive the second synchronization signal block, and the second synchronization signal block is used for the terminal device to access the second access network device.

[0260] or,

[0261] In another possible implementation, the processing module 601 is used to determine the first synchronization signal block; the transceiver module 602 is used to transmit the first synchronization signal block on the first frequency point; the first synchronization signal block is used to indicate the time domain resources of the second synchronization signal block; the time domain resources of the second synchronization signal block are different from the time domain resources of the first synchronization signal block; the second synchronization signal block is used for the terminal device to access the second access network device.

[0262] All relevant content of each step involved in the above method embodiments can be referenced from the functional description of the corresponding functional module, and will not be repeated here.

[0263] In this application, the communication device 60 can be presented in an integrated manner, divided into various functional modules. Here, "module" can refer to an application-specific integrated circuit (ASIC), a circuit, a processor and memory that executes one or more software or firmware programs, integrated logic circuits, and / or other devices that can provide the above functions.

[0264] In some embodiments, when the communication device 60 in FIG6 is a chip or chip system, the function / implementation process of the transceiver module 602 can be implemented through the input / output interface (or communication interface) of the chip or chip system, and the function / implementation process of the processing module 601 can be implemented through the processor (or processing circuit) of the chip or chip system.

[0265] Since the communication device 60 provided in this embodiment can execute the above method, the technical effects it can achieve can be referred to the above method embodiment, and will not be repeated here.

[0266] As a possible product form, the terminal device or first access network device described in the embodiments of this application can be implemented using the following: one or more field programmable gate arrays (FPGAs), programmable logic devices (PLDs), controllers, state machines, gate logic, discrete hardware components, any other suitable circuits, or any combination of circuits capable of performing the various functions described throughout this application.

[0267] As another possible product form, the terminal device or first access network device described in this application embodiment can be implemented using a general bus architecture. For ease of explanation, refer to FIG7, which is a schematic diagram of the structure of a communication device 700 provided in an embodiment of this application. The communication device 700 includes a processor 701 and a transceiver 702. The communication device 700 can be a terminal device, or a chip or chip system therein; or, the communication device 700 can be a first access network device, or a chip or module therein. FIG7 only shows the main components of the communication device 700. In addition to the processor 701 and transceiver 702, the communication device may further include a memory 703 and input / output devices (not shown in the figure).

[0268] Optionally, the processor 701 is mainly used to process communication protocols and communication data, control the entire communication device, execute software programs, and process the data of the software programs, thereby implementing the methods provided in the above-described method embodiments. The memory 703 is mainly used to store software programs and data. The transceiver 702 may include radio frequency (RF) circuitry and an antenna. The RF circuitry is mainly used for converting baseband signals to RF signals and processing RF signals. The antenna is mainly used for transmitting and receiving RF signals in the form of electromagnetic waves. Input / output devices, such as touchscreens, displays, and keyboards, are mainly used to receive user input data and output data to the user.

[0269] Optionally, the processor 701, transceiver 702, and memory 703 can be connected via a communication bus.

[0270] When the communication device is powered on, the processor 701 can read the software program in the memory 703, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be transmitted wirelessly, the processor 701 performs baseband processing on the data to be transmitted and outputs the baseband signal to the radio frequency (RF) circuit. The RF circuit processes the baseband signal and transmits the RF signal outward in the form of electromagnetic waves through the antenna. When data is sent to the communication device, the RF circuit receives the RF signal through the antenna, converts the RF signal into a baseband signal, and outputs the baseband signal to the processor 701. The processor 701 converts the baseband signal into data and processes the data.

[0271] In another implementation, the radio frequency circuitry and antenna can be set up independently of the processor performing baseband processing. For example, in a distributed scenario, the radio frequency circuitry and antenna can be arranged remotely, independent of the communication device.

[0272] In some embodiments, those skilled in the art will recognize that the above-described communication device 60 can take the form of the communication device 700 shown in FIG7 in terms of hardware implementation.

[0273] As an example, the function / implementation process of the processing module 601 in Figure 6 can be implemented by the processor 701 in the communication device 700 shown in Figure 7 calling computer execution instructions stored in the memory 703. The function / implementation process of the transceiver module 602 in Figure 6 can be implemented by the transceiver 702 in the communication device 700 shown in Figure 7.

[0274] As another possible product form, the terminal device or the first access network device in this application may adopt the composition structure shown in FIG8, or include the components shown in FIG8. FIG8 is a schematic diagram of the composition of a communication device 800 provided in this application. The communication device 800 may be a terminal device or a chip or system-on-a-chip in the terminal device; or, it may be a first access network device or a module, chip or system-on-a-chip in the first access network device.

[0275] As shown in Figure 8, the communication device 800 includes at least one processor 801 and at least one communication interface (Figure 8 is only an example illustrating the inclusion of a communication interface 804 and a processor 801). Optionally, the communication device 800 may also include a communication bus 802 and a memory 803.

[0276] Processor 801 can be a general-purpose central processing unit (CPU), a general-purpose processor, a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a PLD, or any combination thereof. Processor 801 can also be other devices with processing capabilities, such as circuits, devices, or software modules, without limitation. As one possible implementation, processor 801 may include one or more CPUs, such as CPU0 and CPU1 in Figure 8.

[0277] The communication bus 802 is used to connect different components in the communication device 800, enabling communication between them. The communication bus 802 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. This bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used in Figure 8, but this does not indicate that there is only one bus or one type of bus.

[0278] Communication interface 804 is used for communicating with other devices or communication networks. For example, communication interface 804 can be a module, circuit, transceiver, or any device capable of communication. Optionally, communication interface 804 can also be an input / output interface located within processor 801, used to implement signal input and signal output for the processor.

[0279] The memory 803 may be a device with storage function, used to store instructions and / or data. The instructions may be computer programs.

[0280] For example, the memory 803 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and / or instructions; it may also be a random access memory (RAM) or other type of dynamic storage device capable of storing information and / or instructions; it may also be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, etc., without limitation.

[0281] It should be noted that the memory 803 can exist independently of the processor 801, or it can be integrated with the processor 801. The memory 803 can be located inside or outside the communication device 800, without limitation. The processor 801 can be used to execute the instructions stored in the memory 803 to implement the methods provided in the following embodiments of this application.

[0282] As an optional implementation, the communication device 800 may also include an output device 805 and an input device 806. The output device 805 communicates with the processor 801 and can display information in various ways. For example, the output device 805 may be a liquid crystal display (LCD), a light-emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector, etc. The input device 806 communicates with the processor 801 and can receive user input in various ways. For example, the input device 806 may be a mouse, keyboard, touchscreen device, or sensing device, etc.

[0283] In some embodiments, those skilled in the art will recognize that the communication device 60 shown in FIG. 6 can take the form of the communication device 800 shown in FIG. 8 in terms of hardware implementation.

[0284] As an example, the function / implementation process of the processing module 601 in Figure 6 can be implemented by the processor 801 in the communication device 800 shown in Figure 8 calling computer execution instructions stored in the memory 803. The function / implementation process of the transceiver module 602 in Figure 6 can be implemented by the communication interface 804 in the communication device 800 shown in Figure 8.

[0285] It is understood that the structure shown in Figure 8 does not constitute a specific limitation on the terminal device or the first access network device. For example, in other embodiments of this application, the terminal device or the first access network device may include more or fewer components than shown in the figure, or combine some components, or split some components, or have different component arrangements. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0286] In some embodiments, this application also provides a communication device, which includes a processor for implementing the methods in any of the above method embodiments.

[0287] As one possible implementation, the communication device also includes a memory. This memory stores necessary computer programs and data. The computer program may include instructions, which a processor can invoke to instruct the communication device to execute the methods described in any of the above method embodiments. Alternatively, the memory may not be present in the communication device.

[0288] As another possible implementation, the communication device also includes an interface circuit, which is a code / data read / write interface circuit, used to receive computer execution instructions (which are stored in memory and may be read directly from memory or may be transmitted through other devices) and transmit them to the processor.

[0289] As another possible implementation, the communication device also includes a communication interface for communicating with modules outside the communication device.

[0290] It is understood that the communication device can be a chip or a chip system. When the communication device is a chip system, it can be composed of chips or may include chips and other discrete devices. This application does not specifically limit this.

[0291] This application also provides a computer-readable storage medium having a computer program or instructions stored thereon, which, when executed by a computer, implements the functions of any of the above-described method embodiments.

[0292] This application also provides a computer program product that, when executed by a computer, implements the functions of any of the above method embodiments.

[0293] This application also provides a communication system. The communication system includes one or more of the following: the terminal device shown in FIG3, the first access network device, or the second access network device; or the communication system includes one or more of the following: the terminal device shown in FIG4, the first access network device, and the second access network device.

[0294] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0295] It is understood that the systems, apparatuses, and methods described in this application can also 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 couplings or direct couplings or communication connections shown or discussed may be through some interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0296] The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. The components shown as units may or may not be physical units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0297] 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.

[0298] 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 programs, implementation can be, in whole or in part, in the form of a computer program product. This 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. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device containing one or more servers, data centers, etc., that can be integrated with the medium. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive (SSD)). In this embodiment, the computer may include the aforementioned apparatus.

[0299] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, disclosure, and appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0300] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the scope of this application. Accordingly, this specification and drawings are merely illustrative descriptions of the application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of the claims and their equivalents, this application is also intended to include such modifications and modifications.

Claims

1. A communication method, characterized in that, The method includes: A first synchronization signal block is received from a first access network device on a first frequency point. The first synchronization signal block includes information about a second frequency point. The second frequency point is different from the first frequency point, and the search priority of the first frequency point is greater than the search priority of the second frequency point. Receive a second synchronization signal block from the second access network device on the second frequency point; Based on the second synchronization signal block, the second access network device is connected.

2. A communication method, characterized in that, The method includes: Determine the first synchronization signal block; The first synchronization signal block is transmitted on a first frequency point. The first synchronization signal block includes information about a second frequency point, which is different from the first frequency point. The search priority of the first frequency point is greater than that of the second frequency point. The second frequency point is used by the terminal device to receive the second synchronization signal block, which is used by the terminal device to access the second access network device.

3. The method according to claim 1 or 2, characterized in that, The information of the second frequency point includes one or more of the following: a first subcarrier offset or first information, wherein the first information is used to indicate the second frequency point; The first subcarrier offset is related to one or more of the following: the synchronization signal block grid corresponding to the second frequency point, or the frequency band to which the second frequency point belongs.

4. The method according to claim 3, characterized in that, The information of the second frequency point also includes first indication information, which is used to indicate that the first information is used to indicate the second frequency point.

5. The method according to claim 3 or 4, characterized in that, The first information is used to schedule the second information, and the second information indicates the second frequency point.

6. The method according to any one of claims 1-5, characterized in that, Both the first frequency point and the second frequency point are frequency points in the first synchronization signal block grid.

7. The method according to any one of claims 1-5, characterized in that, The first frequency point is a frequency point in the second synchronization signal block grid, the second frequency point is a frequency point in the third synchronization signal block grid, and the search priority of the frequency point in the second synchronization signal block grid is greater than the search priority of the frequency point in the third synchronization signal block grid.

8. The method according to any one of claims 1-7, characterized in that, The first synchronization signal block also includes second indication information, which indicates that the first type of terminal device is prohibited from accessing the first frequency point.

9. The method according to any one of claims 1-8, characterized in that, The first access network device is a first satellite, and the second access network device is a second satellite. The altitude of the orbit of the first satellite is greater than or equal to the altitude of the orbit of the second satellite.

10. A communication method, characterized in that, The method includes: A first synchronization signal block is received from a first access network device at a first frequency point. The first synchronization signal block is used to indicate the time domain resources of a second synchronization signal block. The time domain resources of the second synchronization signal block are different from those of the first synchronization signal block. The second synchronization signal block is received from the second access network device on the time domain resources of the first frequency point and the second synchronization signal block; Based on the second synchronization signal block, the second access network device is connected.

11. A communication method, characterized in that, The method includes: Determine the first synchronization signal block; The first synchronization signal block is transmitted at a first frequency point; the first synchronization signal block is used to indicate the time domain resources of the second synchronization signal block; the time domain resources of the second synchronization signal block are different from the time domain resources of the first synchronization signal block. The second synchronization signal block is used for the terminal device to access the second access network device.

12. The method according to claim 10 or 11, characterized in that, The first synchronization signal block includes third indication information; the third indication information is used to indicate that the frequency point corresponding to the first synchronization signal block is the same as the frequency point corresponding to the second synchronization signal block.

13. The method according to any one of claims 10-12, characterized in that, The first synchronization signal block is used to schedule the third information, which indicates the time-domain resources of the second synchronization signal block.

14. The method according to any one of claims 10-13, characterized in that, The first access network device is a first satellite, and the second access network device is a second satellite. The altitude of the orbit of the first satellite is greater than or equal to the altitude of the orbit of the second satellite.

15. A communication device, characterized in that, The communication device includes a module for performing the method as described in any one of claims 1-9, or includes a module for performing the method as described in any one of claims 10-14.

16. A communication device, characterized in that, The communication device includes a processor; the processor is configured to run a computer program or instructions to cause the communication device to perform the method as described in any one of claims 1-9, or to cause the communication device to perform the method as described in any one of claims 10-14.

17. A communication device, characterized in that, The communication device includes: a processor and a communication interface; the communication interface is used to communicate with a module outside the communication device; the processor is used to execute computer programs or instructions to cause the communication device to perform the method as described in any one of claims 1-9, or to cause the communication device to perform the method as described in any one of claims 10-14.

18. The method according to claim 16 or 17, characterized in that, The communication device further includes a memory for storing a computer program, which, when invoked by the processor, causes the communication device to perform the method according to any one of claims 1-9, or to cause the communication device to perform the method according to any one of claims 10-14.

19. A communication device, characterized in that, The communication device is a chip or chip system, the communication device includes a chip, and may also include chips and other discrete devices, the communication device performs the method as described in any one of claims 1-9, or, to cause the communication device to perform the method as described in any one of claims 10-14.

20. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions or programs that, when executed on a computer, cause the method described in any one of claims 1-9 to be performed, or cause the method described in any one of claims 10-14 to be performed.

21. A computer program product, characterized in that, The computer program product includes computer instructions; when some or all of the computer instructions are run on a computer, they cause the method as described in any one of claims 1-9 to be performed, or cause the method as described in any one of claims 10-14 to be performed.

Images