Satellite communication method and apparatus based on time-division duplex TDD frame structure design

Abstract

This application proposes a satellite communication method and apparatus based on a time-division duplex TDD frame structure design, relating to the field of wireless communication. In this solution, a predetermined set of time-division duplex TDD frame structures corresponding to a base station is identified, where the predetermined set of TDD frame structures includes a first TDD frame structure and a second TDD frame structure generated by offsetting the frame header of the first TDD frame structure. In response to receiving a first message transmitted from a terminal, the terminal set to which the terminal belongs is determined, where the terminal set is either a first terminal set or a second terminal set. If the terminal belongs to the first terminal set, scheduling is performed for the terminal based on the first TDD frame structure, and if the terminal belongs to the second terminal set, scheduling is performed for the terminal based on the second TDD frame structure. According to this application, a satellite-borne base station can communicate with some UEs even when communication with some UEs enters a waiting period (i.e., is in the GP period in the corresponding frame structure), thereby improving the overall air interface resource utilization rate of the system.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication, and particularly to a satellite communication method and apparatus based on the design of a time division duplex (TDD) frame structure.

Background Art

[0002] Currently, for low Earth orbit (LEO) satellite systems, whether it is a system already used in orbit or an international standard for 5G non-terrestrial networks (NTN) by 3GPP, it is often considered that an FDD (frequency division duplex) system is used as the satellite-ground service link. However, considering the scarcity of available spectrum resources in the FDD system (especially within the spectrum range of less than 6 GHz), and the low spectrum utilization rate due to the use of uplink / downlink asymmetric traffic as the mainstream traffic pattern in the FDD system, currently, the industry is also actively considering the application of the TDD (time division duplexing) method to the satellite-ground service link.

[0003] Related technologies propose that, in order to fully utilize the time-domain resources in the TDD method, different satellite-borne base stations should project to different cells on the ground, and data can be transmitted and received by cross-using GP (Guard Period) time slots between different cells. However, this approach still has shortcomings in terms of improving resource utilization. In the context of the entire system, only one satellite-borne base station can communicate with several user terminals (User Equipment, abbreviated as UE) during the duration of each segment of a GP time slot belonging to a certain cell, but the system has not yet reached the more ideal state where all satellite-borne base stations in the system can communicate with certain UEs during the duration of each segment of a GP time slot belonging to a certain cell. [Overview of the project] [Problems that the invention aims to solve]

[0004] The satellite communication method and apparatus based on the time-division duplex TDD frame structure design proposed in this application enable a satellite-borne base station to communicate with some UEs even when communication with some UEs enters a waiting period, thereby improving the overall air interface resource utilization rate of the system. [Means for solving the problem]

[0005] An embodiment of the first aspect of the present application is a satellite communication method based on a time-division duplex TDD frame structure design for use in network equipment, comprising the steps of: identifying a predetermined group of time-division duplex TDD frame structures corresponding to a base station, wherein the predetermined group of TDD frame structures includes a first TDD frame structure and a second TDD frame structure generated by offsetting the frame header with respect to the first TDD frame structure; determining the set of terminals to which a terminal belongs in response to receiving a first message transmitted from a terminal, wherein the set of terminals is either a first set of terminals or a second set of terminals; and, if the terminal belongs to the first set of terminals, scheduling the terminal based on the first TDD frame structure; and if the terminal belongs to the second set of terminals, scheduling the terminal based on the second TDD frame structure.

[0006] In the embodiment of the present invention, within a single cell, based on classification and scheduling of UEs by a satellite-borne base station, some ground UEs use a first TTD frame structure, while other ground UEs use a second TDD frame structure as their TDD structure, which is obtained by offsetting the frame header of the first TTD frame structure. Furthermore, all (or some) DL and UL time slots in the second TDD frame structure correspond to the GP time slots in the first TDD frame structure (i.e., they occur at the same time), and simultaneously, all (or some) DL and UL time slots in the first TDD frame structure naturally correspond to the GP time slots in the second TDD frame structure. As a result, the satellite-borne base station can communicate with some UEs even when communication with some UEs enters a waiting period (i.e., is in the GP period in the corresponding frame structure), thereby improving the overall air interface resource utilization rate of the system.

[0007] An embodiment of a second aspect of the present application is a satellite communication method based on a time-division duplex TDD frame structure design used in a user terminal (UE), comprising the steps of: transmitting a first message corresponding to the terminal to a base station; and receiving scheduling from the base station for the terminal based on a first TDD frame structure or a second TDD frame structure, wherein the second TDD frame structure is generated by offsetting the frame header relative to the first TDD frame structure.

[0008] An embodiment of a third aspect of the present application is a satellite communication device based on a time-division duplex TDD frame structure design, which is applied to network equipment, the device comprising: a specific module arranged to identify a predetermined group of time-division duplex TDD frame structures corresponding to a base station, the specific module including a first TDD frame structure and a second TDD frame structure generated by offsetting the frame header with respect to the first TDD frame structure; and a determination module arranged to determine the terminal set to which a terminal belongs in response to receiving a first message transmitted from a terminal, the determination module being either a first terminal set or a second terminal set, a first scheduling module arranged to schedule the terminal based on the first TDD frame structure if the terminal belongs to the first terminal set, and a second scheduling module arranged to schedule the terminal based on the second TDD frame structure if the terminal belongs to the second terminal set.

[0009] A fourth embodiment of the present application proposes a satellite communication device based on a time-division duplex TDD frame structure design, applied to a user terminal (UE), the device comprising: a transmitting module arranged to transmit a first message corresponding to the terminal to a base station; and a scheduling receiving module used in the module and arranged to receive scheduling to the terminal based on a first TDD frame structure or a second TDD frame structure from the base station, wherein the second TDD frame structure is generated by offsetting the frame header relative to the first TDD frame structure.

[0010] An embodiment of the fifth aspect of the present application provides a communication device comprising at least one processor and a memory communicated to the at least one processor, wherein the memory stores a command that the at least one processor can execute, and by executing the command by the at least one processor, the at least one processor can execute a satellite communication method based on the time-division duplex TDD frame structure design described in an embodiment of the first aspect of the present application, or a satellite communication method based on the time-division duplex TDD frame structure design described in an embodiment of the second aspect of the present application.

[0011] An embodiment of the sixth aspect of the present application provides a computer storage medium in which computer-executable commands are stored, and when the computer-executable commands are executed by a processor, a satellite communication method based on the time-division duplex TDD frame structure design described in the embodiment of the first aspect of the present application, or a satellite communication method based on the time-division duplex TDD frame structure design described in the embodiment of the second aspect of the present application, is realized. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram of an exemplary embodiment of a satellite communication method based on a time-division duplex TDD frame structure design provided by the embodiment of the present application. [Figure 2(a)] This is a schematic diagram of a first TDD frame structure in which the sum of the number of DL time slots and the number of UL time slots shown in this application is equal to the number of GP time slots N. [Figure 2(b)] This is a schematic diagram of the frame structure sequence on the base station side, generated by offsetting the frame header of the first TDD frame structure shown in this application by N time slots. [Figure 3(a)] This is a schematic diagram of a first TDD frame structure in which the sum of the number of DL time slots and the number of UL time slots shown in this application is smaller than the number of GP time slots N. [Figure 3(b)] This is a schematic diagram of the frame structure sequence on the base station side, generated by offsetting the frame header for the first TDD frame structure shown in this application. [Figure 4(a)] This is a schematic diagram of a first TDD frame structure in which the sum of the number of DL time slots and the number of UL time slots shown in this application is greater than the number of GP time slots N. [Figure 4(b)] This is a schematic diagram of the frame structure sequence on the base station side, generated by offsetting the frame header for the first TDD frame structure shown in this application. [Figure 5] This is a schematic diagram illustrating frequency division multiplexing using subbands as the granularity, performed by the subband full-duplex technology shown in this application. [Figure 6] This is a schematic diagram illustrating the generation of shared channel crosslink interference between UEs as shown in this application. [Figure 7] This is a schematic diagram of an exemplary embodiment of a satellite communication method based on the time-division duplex TDD frame structure design shown in this application. [Figure 8] This is a schematic diagram illustrating the generation of shared channel crosslink interference between UEs as shown in this application. [Figure 9] This is a schematic diagram of an exemplary embodiment of a satellite communication method based on the time-division duplex TDD frame structure design shown in this application. [Figure 10]It is a schematic diagram of an exemplary embodiment of a satellite communication method based on the time division duplex (TDD) frame structure design shown in the present application. [Figure 11] It is a schematic diagram that divides the coverage area of the base station shown in the present application into an outer circle and an inner circle. [Figure 12] It is a schematic diagram for specifying the transmission time slot of CD-SSB by taking the design method of the first type of frame structure group as an example. [Figure 13] It is a schematic diagram of an exemplary embodiment of a satellite communication method based on the time division duplex (TDD) frame structure design shown in the present application. [Figure 14] It is a structural schematic diagram of a satellite communication device based on the time division duplex (TDD) frame structure design proposed in the embodiment of the present application. [Figure 15] It is a structural schematic diagram of another satellite communication device based on the time division duplex (TDD) frame structure design proposed in the embodiment of the present application. [Figure 16] It is a schematic diagram of a communication device provided by the embodiment of the present application.

Embodiments for Carrying Out the Invention

[0013] The following will describe the embodiments of the present application in detail. Examples of the embodiments are shown in the accompanying drawings, in which elements that are the same or similar, or elements having the same or similar functions, are consistently denoted by the same or similar reference numerals. Hereinafter, the embodiments described with reference to the accompanying drawings are exemplary only and are merely for interpreting the present application and should not be understood as limiting the present application.

[0014] In the related art, for a TDD system to operate properly, among the frame formats used, the required GP (Guard Period) when performing the conversion between the DL (Downlink) time slot and the UL (Uplink) time slot is the round-trip time (RTT) of signal transmission between the base station and the far point of the cell. radiusIt is necessary that the following conditions are met: (as noted above). When applying the TDD method to satellite-ground service links for low-Earth orbit satellites, considering the long signal transmission distance between the satellite and the user equipment (UE) on the ground, RTT radius As the quantity level increases, the duration of the GP also increases. Consequently, due to the longer GP duration, the overall air interface resource utilization rate of the system is relatively low.

[0015] For example, regarding a certain low Earth orbit satellite system, RTT radius The quantity level is set to 5 milliseconds (abbreviated as ms). Typically, GP is RTT. radius It may be set to be equal to , so in the example above, GP is equal to 5 milliseconds. If the subcarrier interval used is 30 kHz (i.e., the duration of each time slot is 0.5 ms), then between the DL time slot and the UL time slot, there are required 10 special time slots, all of which are GP (in the explanation below, special time slots that are all GP will be referred to as "GP time slots").

[0016] Some proposals suggest that, in order to fully utilize the time-domain resources in the TDD method, different satellite-borne base stations should project to different ground cells, and that data can be transmitted and received using cross-platform GP (Guard Period) time slots between different cells. However, these proposals have the following problems.

[0017] 1. Such a plan still falls short in terms of improving resource utilization. In the context of the entire system, only one satellite-borne base station can communicate with several user equipment (UEs) during the duration of each segment of a GP time slot belonging to a given cell. However, the more ideal state has not yet been reached where all satellite-borne base stations in the system can communicate with certain UEs during the duration of each segment of a GP time slot belonging to a given cell.

[0018] 2. Furthermore, if this solution is used, a situation may arise where one UE located on the cell edge of one cell and another edge UE in an adjacent cell are receiving downlink signals while the other UE is transmitting uplink signals. If the distance between these two edge UEs located in different cells is short, "inter-UE shared channel crosslink interference" will occur. Unless such interference can be better avoided, this solution cannot be implemented.

[0019] 3. Furthermore, if such a method is used, the starting position of the system frame in different cells must be slid and then shifted, which places very strict requirements on temporal synchronization between adjacent satellites.

[0020] 4. Furthermore, there is no general, standard design for the distribution ratio between the number of DL time slots, UL time slots, and GP time slots, and only one example is given here.

[0021] To solve the above technical problems, the embodiment of the present application provides a satellite communication method and apparatus based on the following time-division duplex TDD frame structure design.

[0022] Figure 1 is a schematic diagram of an exemplary embodiment of a satellite communication method based on the time-division duplex TDD frame structure design shown in the present application. As shown in Figure 1, the satellite communication method based on the time-division duplex TDD frame structure design is used in network equipment and includes the following steps.

[0023] Step S101: Identify a predetermined set of time-division duplex TDD frame structures corresponding to a base station, wherein the predetermined set of TDD frame structures includes a first TDD frame structure and a second TDD frame structure generated by offsetting the frame header of the first TDD frame structure.

[0024] In this application, the following three predetermined TDD frame structure design methods are offered as options.

[0025] In the first feasible frame structure design method, the method for obtaining a predetermined group of TDD frame structures includes the step of setting up a first TDD frame structure, wherein the number of protection interval (GP) time slots of the first TDD frame structure is N (where N is a positive integer), and the sum of the number of downlink (DL) time slots and the number of uplink (UL) time slots in the first TDD frame structure is equal to N. Figure 2(a) is a schematic diagram of the first TDD frame structure shown in this application, in which the sum of the number of DL time slots and the number of UL time slots is equal to the number of GP time slots N. The method also includes the step of obtaining a second TDD frame structure by offsetting the frame header of the first TDD frame structure by N time slots based on Figure 2(a). Here, Figure 2(b) is a schematic diagram of the frame structure sequence on the base station side generated by offsetting the frame header of the first TDD frame structure shown in this application by N time slots. As shown in Figure 2(b), all DL time slots and all UL time slots in the second TDD frame structure correspond to all GP time slots in the first TDD frame structure, and the satellite-borne base station can use the first TDD frame structure and the second TDD frame structure simultaneously to schedule some UEs. The invention further includes the step of generating a predetermined set of TDD frame structures based on the first TDD frame structure and the second TDD frame structure after identifying the first TDD frame structure and the second TDD frame structure.

[0026] In the implementation of the first type of frame structure design, the satellite-borne base station can always communicate with several UEs, and there is absolutely no period during which it "needs to be on standby."

[0027] In the implementation of the first type of frame structure design, the network side does not experience collisions in the upstream or downstream directions in any time slot, nor does it introduce any new, unnecessary interference.

[0028] In the second feasible frame structure design method, the method for obtaining a predetermined group of TDD frame structures includes the step of setting up a first TDD frame structure, wherein the number of GP time slots in the first TDD frame structure is N, and the sum of the number of DL time slots and the number of UL time slots in the first TDD frame structure is less than N. Figure 3(a) is a schematic diagram of the first TDD frame structure shown in this application in which the sum of the number of DL time slots and the number of UL time slots is less than the number of GP time slots N, and the method also includes the step of obtaining a second TDD frame structure by offsetting the frame header of the first TDD frame structure based on Figure 3(a). Here, Figure 3(b) is a schematic diagram of the frame structure sequence on the base station side generated by offsetting the frame header to the first TDD frame structure shown in this application. As shown in Figure 3(b), all DL time slots and all UL time slots in the second TDD frame structure correspond to some GP time slots in the first TDD frame structure, and the satellite-borne base station can use the first TDD frame structure and the second TDD frame structure simultaneously to schedule some UEs. The invention further includes the step of generating a predetermined set of TDD frame structures based on the first TDD frame structure and the second TDD frame structure after identifying the first TDD frame structure and the second TDD frame structure.

[0029] In the implementation of the second type of frame structure design, the satellite-borne base station cannot always communicate with several UEs, meaning there are periods when it "needs to be on standby." In the example shown in Figure 3(b), two consecutive time slots are wasted.

[0030] In the implementation of the second type of frame structure design, the network side does not experience collisions in the upstream or downstream directions in any time slot, nor does it introduce any new, unnecessary interference.

[0031] In the third feasible frame structure design method, the method for obtaining a predetermined group of TDD frame structures includes the step of setting up a first TDD frame structure, wherein the number of GP time slots in the first TDD frame structure is N, and the sum of the number of DL time slots and the number of UL time slots in the first TDD frame structure is greater than N. Figure 4(a) is a schematic diagram of the first TDD frame structure shown in this application in which the sum of the number of DL time slots and the number of UL time slots is greater than the number of GP time slots N, and the method also includes the step of obtaining a second TDD frame structure by offsetting the frame header of the first TDD frame structure based on Figure 4(a). Here, Figure 4(b) is a schematic diagram of the frame structure sequence on the base station side generated by offsetting the frame header with respect to the first TDD frame structure shown in this application. As shown in Figure 4(b), some of the time slots among all DL time slots and all UL time slots in the second TDD frame structure correspond to all GP time slots in the first TDD frame structure, and collision slots exist between the first TDD frame structure and the second TDD frame structure. The satellite-borne base station can use the first TDD frame structure and the second TDD frame structure simultaneously to schedule some UEs. The invention further includes the step of generating a predetermined set of TDD frame structures based on the first TDD frame structure and the second TDD frame structure.

[0032] In the implementation of the third type of frame structure design, as shown in the example in Figure 4(b), two DL time slots in each frame period of the second TDD frame structure collide with two UL time slots in each frame period of the first TDD frame structure in the up and down directions, and these two time slots are designated as collision time slots.

[0033] In the implementation of the third type of frame structure design, the satellite-borne base station can always communicate with several UEs, meaning there is no period during which it "needs to be on standby."

[0034] Step S102: In response to receiving the first message sent from the terminal, determine the terminal set to which the terminal belongs, and the terminal set is either the first terminal set or the second terminal set.

[0035] Here, the first set of terminals is the set that has been called to be constructed using terminals of the first TDD frame structure.

[0036] Here, the second set of terminals is the set that has been called to be constructed using terminals of the second TDD frame structure.

[0037] Selectively, the first message is the message in which the terminal reports its location measurement result for the first time after completing the initial random access.

[0038] Selectively, the first message is the initial message that a terminal sends to the base station when it initiates initial random access.

[0039] When a base station receives the first message transmitted from a terminal, it determines the terminal set to which the terminal belongs according to predetermined terminal set determination rules. These terminal set determination rules include, but are not limited to, terminal quantity balancing rules or dice-rolling random rules.

[0040] Step S103: If the terminal belongs to the first set of terminals, scheduling is performed for the terminal based on the first TDD frame structure.

[0041] Step S104: If the terminal belongs to the second set of terminals, scheduling is performed for the terminal based on the second TDD frame structure.

[0042] In the embodiment of the present invention, within a single cell, based on classification and scheduling of UEs by a satellite-borne base station, some ground UEs use a first TTD frame structure, while other ground UEs use a second TDD frame structure as their TDD structure, which is obtained by offsetting the frame header of the first TTD frame structure. Furthermore, all (or some) DL and UL time slots in the second TDD frame structure correspond to the GP time slots in the first TDD frame structure (i.e., they occur at the same time), and simultaneously, all (or some) DL and UL time slots in the first TDD frame structure naturally correspond to the GP time slots in the second TDD frame structure. As a result, the satellite-borne base station can communicate with some UEs even when communication with some UEs enters a waiting period (i.e., is in the GP period in the corresponding frame structure), thereby improving the overall air interface resource utilization rate of the system.

[0043] Based on the above embodiment, in actual use, when a predetermined TDD frame structure is implemented based on the third type of frame structure design, the following two methods may be used to prevent interference from being drawn into the network side.

[0044] 1. In a feasible method for preventing interference from being drawn into the network side of type 1, collision slots located in the first TDD frame structure may be muted, or collision slots located in the second TDD frame structure may be muted, in order to prevent interference from being drawn into the network side.

[0045] Such muting processes do not introduce unnecessary interference to the network. Moreover, base stations do not need to be in a "standby state" as desired. Of course, this means that some UEs will lose a small amount of downlink (or uplink) communication opportunities. Therefore, although the overall air interface resource utilization of the system improves, it is not the optimal method. Taking the specific frame structure shown in Figure 4(b) as an example, one specific process is to set the two DL time slots (collision time slots) in each frame cycle of the second TDD frame structure to muting (i.e., DL scheduling is not performed for UEs that use the second TDD frame structure in either of the two time slots). This is because, in that case, UEs that are scheduled to use the second TDD frame structure will lose a small amount of DL reception opportunities during each frame cycle. Therefore, when scheduling, depending on the amount of downlink data from different users, UEs with relatively small downlink data requests may be given priority to use the second TDD frame structure.

[0046] 2. In feasible methods for preventing interference from being drawn into the Type 2 network, in order to prevent interference from being drawn into the network, for collision slots, in the case of scheduling by the base station, it may be selected to perform subband-level frequency division multiplexing using subband full-duplex technology for the reception of uplink data from terminals scheduled by the base station and using one of the first and second TDD frame structures, and for the transmission of downlink data from terminals scheduled by the base station and using the other of the first and second TDD frame structures (Note that, according to the definition in Re1-18, "subband full-duplex" only enhances the duplex operation performed on the base station side and maintains half-duplex operation on the terminal side). Figure 5 is a schematic diagram of subband-level frequency division multiplexing using subband full-duplex technology as shown in this application.

[0047] Taking the specific frame structure shown in Figure 4(b) as an example, when scheduling is performed for each of the two time slots in which a collision occurs, the satellite-borne base station uses subband full-duplex technology to perform frequency division multiplexing with subband granularity for the reception of uplink data from terminals scheduled by the base station to use the first TDD frame structure, and for the transmission of downlink data from terminals scheduled by the base station to use the second TDD frame structure.

[0048] Furthermore, for the reception of uplink data from terminals using one of the first or second TDD frame structures scheduled by the base station, and the transmission of downlink data from terminals using the other of the first or second TDD frame structures scheduled by the base station, frequency division multiplexing with subband granularity is performed using subband full-duplex technology. At the base station, the remaining inter-subband interference includes "base station self-interference (gNB's self interference)" and "inter-subband cross-link interference on shared channels between base stations (gNB-to-gNBco-channel inter-subband cross-link interference)." Good interference avoidance can be obtained for both of the above interferences by using the interference avoidance methods considered for "subband full-duplex" in Re1-18. As a specific interference avoidance method, interference rejection may be performed against two types of inter-subband interference remaining on the network side, including base station self-interference and inter-subband crosslink interference on shared channels between base stations, by one or more of the following methods: interference rejection methods in the spatial domain (e.g., design for separation of transmitting and receiving antennas and increasing the separation between antennas), interference rejection methods in the analog domain (e.g., improving filtering performance by increasing the analog high square coefficient filter), and interference rejection methods in the digital domain (e.g., signal processing for interference cancellation performed via information at the transmitting end).

[0049] Regardless of which of the three feasible frame structure designs described above is used, no inter-UE interference will occur between any two UEs within the same frame structure's set of UEs. Below, we will further analyze the "UE-to-UE co-channel cross-link interference" that may occur between UEs using the first TDD frame structure and UEs using the second TDD frame structure.

[0050] 1. In the case where the first type frame structure design method, the second type frame structure design method, and the third type frame structure design method are used, and the muting method is used to handle the occurrence of uplink / downlink collisions in some time slots on the network side, In a terrestrial network, there should be no inter-UE shared channel crosslink interference between UEs using the first TDD frame structure and UEs using the second TDD frame structure within a cell. However, Figure 6 is a schematic diagram illustrating the generation of inter-UE shared channel crosslink interference as described in this application. As shown in Figure 6, satellite-terrestrial links have enormous propagation distances, so it is possible that a situation may arise where one UE in a set of UEs using the first TDD frame structure (i.e., the first terminal set) and another UE in a set of UEs using the second TDD frame structure (i.e., the second terminal set) are receiving downlink signals while the other is transmitting uplink signals. In that case, if the distance between the two UEs is short, inter-UE shared channel crosslink interference will occur.

[0051] 2. When a Type 3 frame structure design method is used, and to address the occurrence of uplink / downlink collisions in some time slots on the network side, a subband full-duplex processing method is used, which is a feasible method to prevent interference from being drawn into the Type 2 network side. In both terrestrial networks and LEO satellite networks, inter-UE shared channel crosslink interference inevitably exists between UEs using the first TDD frame structure and UEs using the second TDD frame structure within a cell. In this case, collisions occur in both the uplink and downlink directions for a small time slot on the network side, so we propose resolving these collisions using subband full-duplex technology.

[0052] Then, to address the inter-UE shared channel crosslink interference within a cell that may occur between "a certain UE in the UE set using the first TDD frame structure (i.e., the first terminal set)" and "a certain UE in the UE set using the second TDD frame structure (i.e., the second terminal set)," we divide it into two types: shared channel crosslink interference that may exist between "UEs after initial random access has started," and shared channel crosslink interference that may exist between "a UE performing the initial random access initiation operation" and "a UE that initiated initial random access" within a cell, and design interference avoidance measures for each.

[0053] Figure 7 is a schematic diagram of an exemplary embodiment of a satellite communication method based on the time-division duplex TDD frame structure design shown in this application. This embodiment mainly describes a method for avoiding shared channel crosslink interference that may exist between "UEs after initial random access has commenced" by using a subband-level frequency division scheduling scheme. As shown in Figure 7, the satellite communication method based on the time-division duplex TDD frame structure design includes the following steps.

[0054] Step S701: Identify a predetermined set of time-division duplex TDD frame structures corresponding to a base station, wherein the predetermined set of TDD frame structures includes a first TDD frame structure and a second TDD frame structure generated by offsetting the frame header of the first TDD frame structure.

[0055] Step S702: In response to receiving the first message sent from the terminal, determine the terminal set to which the terminal belongs, and the terminal set is either the first terminal set or the second terminal set.

[0056] Step S703: If the terminal belongs to the first set of terminals, scheduling is performed for the terminal based on the first TDD frame structure.

[0057] Step S704: If the terminal belongs to the second set of terminals, schedule the terminal based on the second TDD frame structure.

[0058] For specific details on how steps S701 to S704 are implemented, please refer to the detailed explanation in the section concerning steps S101 to S104 in the above embodiment. The explanation is omitted here.

[0059] Step S705: If inter-terminal shared channel crosslink interference exists between any first terminal belonging to the first terminal set and any second terminal belonging to the second terminal set, interference avoidance is performed by a subband-level frequency division scheduling scheme.

[0060] The following describes interference avoidance using subband-level frequency division scheduling, divided into two cases.

[0061] 1. In the case where the first type frame structure design method, the second type frame structure design method, and the third type frame structure design method are used, and the muting method is used to handle the occurrence of uplink / downlink collisions in some time slots on the network side, On the network side, no collisions occur in the uplink or downlink directions, so in that case, frequency division scheduling at the subband level was performed. However, at the base station, the transmit / receive operation at any given time is not equivalent to "subband full duplex," and there is no "base station self-interference" or "inter-subband crosslink interference on shared channels between base stations."

[0062] Simultaneously, to make it easier to understand, if, after frequency division at the subband level has been performed on the UE side, there remains "UE-to-UE co-channel inter-subband cross-link interference" between terminals, a method that provides good interference avoidance, as considered for "subband full duplex" in Re1-18, may be used as a specific interference avoidance method. Specifically, interference rejection may be performed by one or more of the following methods: interference rejection methods in the spatial domain (e.g., increasing the separation design of transmitting and receiving antennas and the spacing between antennas), interference rejection methods in the analog domain (e.g., improving filtering performance by increasing the number of analog high square coefficient filters), and interference rejection methods in the digital domain (e.g., signal processing for interference cancellation performed via information at the transmitting end). Figure 8 is a schematic diagram illustrating the generation of UE-to-UE co-channel cross-link interference as shown in this application.

[0063] 2. When a third type of frame structure design method is used, and to address the occurrence of uplink / downlink collisions in some time slots on the network side, a subband full-duplex processing method is used, For some of the collision time slots where uplink / downlink collisions occur on the network side, the "subband full-duplex" method was used for those collision time slots, so it was inevitable that subband-level frequency division scheduling had already been achieved. Furthermore, it would be desirable to exclusively perform subband-level frequency division scheduling for the other time slots (note that at the base station, transmission and reception operations at any of those other time slots are not equivalent to "subband full-duplex").

[0064] Simultaneously, to make it understandable, if, after similarly, frequency division at the subband level has been performed on the UE side, and there remains "UE-to-UE co-channel inter-subband cross-link interference" between terminals, a method that provides good interference avoidance, as considered for "subband full duplex" in Re1-18, may be used as a specific interference avoidance method. Specifically, interference rejection may be performed by one or more of the following methods: interference rejection methods in the spatial domain (e.g., increasing the separation design of transmitting and receiving antennas and the spacing between antennas), interference rejection methods in the analog domain (e.g., improving filtering performance by increasing the number of analog high square coefficient filters), and interference rejection methods in the digital domain (e.g., signal processing for interference cancellation performed via information from the transmitting end).

[0065] Figure 9 is a schematic diagram of an exemplary embodiment of a satellite communication method based on the time-division duplex TDD frame structure design shown in the present application. This embodiment mainly describes a method for avoiding shared channel crosslink interference that may exist between "UEs after initial random access has been initiated" due to geographical separation. As shown in Figure 9, the satellite communication method based on the time-division duplex TDD frame structure design includes the following steps.

[0066] Step S901: Identify a predetermined set of time-division duplex TDD frame structures corresponding to a base station, wherein the predetermined set of TDD frame structures includes a first TDD frame structure and a second TDD frame structure generated by offsetting the frame header of the first TDD frame structure.

[0067] Regarding the specific implementation method for step S901, there are a total of three predetermined TDD frame structure design methods. Please refer to the detailed explanation in the relevant section of step S101 in the above embodiment. The explanation will be omitted here.

[0068] Step S902: In response to receiving the first message sent from the terminal, the first set of location information corresponding to each first terminal in the first set of terminals is obtained, and the first terminal and the base station are connected.

[0069] Here, the first set of terminals is the set that has been called to be constructed using terminals of the first TDD frame structure.

[0070] Each terminal in the first set of terminals is designated as a first terminal. The location information of each first terminal is obtained as the first location information, and a first set of location information is generated based on all of the first location information.

[0071] Selectively, when the first terminal reports a conventional measurement report message, it piggybacks and reports its own location information. Therefore, the base station stores the location information reported at least once immediately before and retrieves it from its own memory when necessary.

[0072] Selectively, base stations use "terminal information request messages" to display or perform real-time searches for the location information of the first terminal.

[0073] Selectively, the first terminal can exclusively report its own location information periodically or triggered by an event (for example, when it is detected that the change in distance due to a change in its own position exceeds a certain threshold). Therefore, the base station stores the location information reported at least once immediately before and retrieves it from its own memory when necessary.

[0074] Step S903: The second location information set corresponding to each second terminal in the second terminal set is obtained, and the second terminal and the base station are connected.

[0075] Here, the second set of terminals is the set that has been called to be constructed using terminals of the second TDD frame structure.

[0076] Each terminal in the second set of terminals is designated as a second terminal. The location information of each second terminal is obtained as second location information, and a second set of location information is generated based on all of the second location information.

[0077] Step S904: Obtain the terminal location information corresponding to the terminal.

[0078] The system obtains terminal location information corresponding to the terminal that sends the first message, that is, terminal location information corresponding to the terminal that the base station determines whether to be called based on the first TDD frame structure or the second TDD frame structure.

[0079] Step S905: Based on the first set of location information, the second set of location information, and the terminal location information, determine the terminal set to which the terminal belongs.

[0080] In the LEO satellite system, each UE reports its geographical location information to the satellite-borne base station using GNSS (for example, China's "Beidou system").

[0081] Each cell in a LEO satellite system has a very large ground coverage area (hundreds of thousands, or even millions, of square meters), so each cell has a sufficiently large geographical space, and as a result, the distance between any two UEs within the cell is large enough to effectively avoid mutual interference between them.

[0082] To make it easier to understand, a base station using two different frame structures to schedule some of the UEs within a cell is equivalent to dividing the corresponding UEs within the cell into two sets of users.

[0083] Therefore, in order to avoid "inter-UE shared channel crosslink interference" within a cell, when scheduling by a base station, it is conceivable that the geographical distance between "any UE in the UE set using the first TDD frame structure" and "any UE in the UE set using the second TDD frame structure" should be greater than the first planned distance threshold.

[0084] Specifically, when a base station determines whether a UE will use a first TDD frame structure or a second TDD frame structure after initial random access has begun, it first obtains the minimum distance among the distances between terminals and each first terminal in the first terminal set as the first distance, based on the first location information set and terminal location information.

[0085] Then, based on the second set of location information and terminal location information, the minimum distance among the distances between the terminal and each second terminal in the second set of terminals is obtained as the second distance.

[0086] The first and second distances are compared to the first planned distance threshold to determine the set of terminals to which the terminal belongs. As a result of this determination, several situations may arise, as shown below.

[0087] If both the first and second distances are greater than or equal to the first planned distance threshold, the base station can determine that its UE may use either the first TDD frame structure or the second TDD frame structure. In other words, in that case, inter-UE interference can be avoided solely by geographical separation. Then, the base station can determine that the terminal belongs to the first terminal set, or that the terminal belongs to the second terminal set.

[0088] Furthermore, if the first distance is greater than or equal to the first planned distance threshold, and the second distance is less than the first planned distance threshold, it is determined that the terminal belongs to the first set of terminals. In other words, in that case, interference between UEs can be avoided by geographical separation alone.

[0089] Then, if the first distance is less than the first planned distance threshold, and the second distance is greater than or equal to the first planned distance threshold, it is determined that the terminal belongs to the second set of terminals. In other words, in that case, interference between UEs can be avoided by geographical separation alone.

[0090] Furthermore, if both the first and second distances are less than the first planned distance threshold, that is, if interference between UEs cannot be avoided by geographical separation alone, the terminal set to which the terminal belongs is determined according to predetermined terminal set determination rules. Determining the terminal set to which a terminal belongs according to predetermined terminal set determination rules includes, but is not limited to, determining the terminal set to which a terminal belongs according to terminal quantity equilibrium rules within the first and second terminal sets, or determining the terminal set to which a terminal belongs according to a rule that randomly selects one of them.

[0091] Step S906: If the terminal belongs to the first set of terminals, schedule the terminal based on the first TDD frame structure.

[0092] Step S907: If the terminal belongs to the second set of terminals, schedule the terminal based on the second TDD frame structure.

[0093] In the embodiment of the present invention, within a single cell, based on classification and scheduling of UEs by a satellite-borne base station, some ground UEs use a first TTD frame structure, while other ground UEs use a second TDD frame structure as their TDD structure, which is obtained by offsetting the frame header of the first TTD frame structure. Furthermore, all (or some) DL and UL time slots in the second TDD frame structure correspond to the GP time slots in the first TDD frame structure (i.e., they occur at the same time), and simultaneously, all (or some) DL and UL time slots in the first TDD frame structure naturally correspond to the GP time slots in the second TDD frame structure. As a result, the satellite-borne base station can communicate with some UEs even when communication with some UEs enters a waiting period (i.e., is in the GP period in the corresponding frame structure), thereby improving the overall air interface resource utilization rate of the system.

[0094] Furthermore, if both the first distance and the second distance are less than the first planned distance threshold, the terminal set to which the terminal belongs is determined according to a predetermined terminal set determination rule, If the terminal to which the terminal belongs is the second terminal set, then, based on the first location information set and the terminal location information, a first terminal subset is obtained in which the distance value to the terminal in the first terminal set is less than the first planned distance threshold, and a subband-level frequency division scheduling scheme is used to avoid shared channel crosslink interference between the terminal and each terminal in the first terminal subset, and If the terminal set to which the terminal belongs is the first terminal set, the system includes obtaining a second terminal subset in the second terminal set whose distance value to the terminal is less than the first planned distance threshold, based on the second location information set and the terminal location information, and avoiding shared channel crosslink interference between the terminal and each terminal in the second terminal subset using a subband level frequency division scheduling scheme.

[0095] Furthermore, since UEs are mobile, the geographical distance between UEs changes. When location update information is received from any first terminal in the first terminal set or any second terminal in the second terminal set, the terminal set corresponding to the terminal reporting the location update information is identified again based on the location update information, in accordance with steps S902 to S905 above.

[0096] Furthermore, it is conceivable to perform further optimization processing as follows: In response to changes in the distance between UEs, the base station may, at an appropriate timing, switch the frame structure used for a particular UE between the first TDD frame structure and the second TDD frame structure. This maximizes the avoidance of inter-UE interference solely through geographical separation.

[0097] When determining the terminal set corresponding to a terminal reporting location update information based on the location update information, the terminal set to which at least one terminal that did not report location update information in the first and second terminal sets belongs is changed, thereby minimizing the number of terminals that need to avoid inter-terminal shared channel crosslink interference by the subband level frequency division scheduling scheme in the updated first and second terminal sets.

[0098] It should be noted that when the first, second, and third frame structure design methods are used, and when a muting method is used to address uplink / downlink collisions occurring in some time slots on the network side, even if two UEs using different frame structures are in a situation where "one UE is receiving downlink data while the other is transmitting uplink data," "inter-UE shared channel crosslink interference" will not occur unless the distance between the two UEs is close. Therefore, when the first, second, and third frame structure design methods are used, and when a muting method is used to address uplink / downlink collisions occurring in some time slots on the network side, "inter-UE shared channel crosslink interference" can be avoided by the geographical separation method described in this embodiment.

[0099] It should be noted that when a Type 3 frame structure design method is used, and when a subband full-duplex processing method is used to address the occurrence of uplink / downlink collisions in some time slots on the network side, since it has already been decided to perform subband full-duplex processing for scheduling a small number of time slots, "inter-UE shared channel crosslink interference" will inevitably exist between UEs using different frame structures at times corresponding to several time slots, regardless of their geographical distance from each other. Therefore, when such a specific frame structure design is used, avoiding "inter-UE shared channel crosslink interference" by the geographical separation method described in this embodiment is neither appropriate nor recommended. In that case, it is sufficient to avoid "inter-UE shared channel crosslink interference" by using the subband-level frequency division scheduling method described in the above embodiment.

[0100] The following describes three feasible methods for avoiding shared channel crosslink interference that may exist between the UE performing the initial random access initiation operation and the UE that initiated the initial random access within a cell.

[0101] The factors that cause such interference are thought to be as follows: For any idle UE, before it initiates initial random access to the satellite-borne base station, the base station cannot accurately determine its geographical location, nor can it accurately determine which of the two frame structures it will use to send the first random access message (i.e., Msgl or MsgA) containing the PRACH preamble sequence (Physical Random Access Channel preamble sequence). Therefore, the first random access message from the UE initiating the initial random access causes inter-UE shared channel crosslink interference for UEs that have initiated the initial random access, and countermeasures to avoid this interference are solely the responsibility of the design.

[0102] The following are the countermeasures for the above-mentioned avoidance measures:

[0103] If the first message is the message in which a terminal reports its location measurement result for the first time after completing initial random access, the TDD frame structure placement information carried in the first system message broadcast by the base station is the placement information corresponding to the first TDD frame structure, and the terminal is determined to belong to the first terminal set if, after the base station has received the first message out of all messages sent by the terminal before sending the first message, the terminal is not yet assigned to the first or second terminal set at that time. Here, the reporting time of the message for reporting the location measurement result for the first time corresponding to the terminal is after the terminal has completed initial random access, completed individual identification, access verification and encryption with the core network by the Non-Access Layer (NAS), and completed the security mode control process with the base station through air interface interaction.

[0104] The first message is the first message that a terminal sends to the base station when it initiates initial random access. When the terminal first reports a location measurement result corresponding to it, it sends the first message along with the first system message to the base station, using pre-allocated time-frequency resources in the system message. The TDD frame structure arrangement information carried in the first system message, which is broadcast by the base station, is arrangement information corresponding to the first TDD frame structure, and the terminal sends the first message using the sequence of the first TDD frame structure.

[0105] Regardless of whether the first message falls under one of the two types of messages described above, in this invention, when a base station performs downlink time-frequency resource scheduling for any terminal belonging to the second set of terminals, it determines the slot index of a UL time slot in the first TDD frame structure that is configured to transmit a random access preamble sequence therein, obtains the slot indices of a plurality of consecutive DL time slots in the second TDD frame structure that are within a predetermined slot range and are located at a distance from the UL time slot in the first TDD frame structure that is configured to transmit a random access preamble sequence therein, and performs frequency domain resource scheduling for each DL time slot among the plurality of consecutive DL time slots within the predetermined slot range in the second TDD frame structure, thereby realizing subband-level frequency division scheduling together with air interface resources configured to perform initial random access to terminals in the first set of terminals. Specifically, each idle UE is selected using the sequence in the first TDD frame structure and initiated with initial random access (i.e., it sends a Msgl for 4-stage random access or a MsgA for 2-stage random access using the sequence in the first TDD frame structure). Simultaneously, when the base station performs DL scheduling for UE(s) in the "UE set using the second TDD frame structure," it avoids frequency domain resources corresponding to PRACH occasions in the frequency domain, using subbands as the smallest granularity, for the consecutive DL time slots in the second TDD frame structure that are closest to the "UL time slot on which the random access preamble sequence in the first TDD frame structure can be sent."Assuming that there is indeed an idle UE initiating initial random access, and that there are "UE(s) using a second TDD frame structure" simultaneously performing DL reception at a location less than the geographical separation threshold from that UE, the remaining subband interference in these "UE(s) using a second TDD frame structure" will be addressed by organically combining the interference rejection methods in the spatial, analog, and digital domains considered in Rel-18.

[0106] Theoretically, even if all idle UEs are selected and initiated with initial random access using the sequence in the first TDD frame structure, connected UEs are not necessarily initiated with initial random access using the sequence in the first TDD frame structure (it should be noted that connected UEs may need to initiate initial random access in some cases, such as during a handover). Therefore, a more rational approach is to initiate initial random access using the sequence in the currently used frame structure (which may mean initiating initial random access using the sequence in the second TDD frame structure). For this reason, the second TDD frame structure is similarly configured to broadcast the PRACH occasion. Thus, theoretically, the PRACH occasions broadcast in the first and second TDD frame structures could be configured in different ways, but a simpler and more efficient approach is to configure the PRACH occasions broadcast in the first and second TDD frame structures to be in exactly the same way. Therefore, based on the hypothesis that they are "set to be in exactly the same configuration," the above explanation does not distinguish between PRACH occasions configured for "UE sets using the first TDD frame structure" and PRACH occasions configured for "UE sets using the second TDD frame structure" when PRACH occasions are mentioned.

[0107] Furthermore, since there are many PRACH formats in which the PRACH transmission period is 1 frame (i.e., each radio frame has a PRACH occasion within the duration of the UL time slot), avoiding the frequency domain resources corresponding to the PRACH occasion in the frequency domain, with the subband as the smallest granularity, for the continuous DL time slots in the second TDD frame structure that are closest to the "UL time slot in the first TDD frame structure on which the random access preamble sequence can be transmitted," is equivalent to creating a subband-level frequency domain separation from the PRACH occasion for each set of continuous DL time slots in the first TDD frame structure.

[0108] In this workaround, terminals that are idle and have not yet initiated initial random access to the base station do not belong to either the first or second set of terminals.

[0109] The following are the countermeasures for the above-mentioned avoidance measures:

[0110] In this application, when the first message is the first message transmitted to the base station when the terminal initiates initial random access, and when the terminal first reports a location measurement result corresponding to the terminal, the TDD frame structure arrangement information carried in the first system message, which is transmitted to the base station and broadcast by the base station, is arrangement information corresponding to the first TDD frame structure, using pre-allocated time-frequency resources in the system message.

[0111] In that case, as a feasible method, the method for determining whether or not to send the first message, and the method for determining the corresponding frame structure when sending the first message, The TDD frame structure arrangement information carried in the first system message broadcast by the base station is arrangement information corresponding to the first TDD frame structure. The second system message broadcast by the base station carries the location information of terminals already assigned to the second set of terminals at the current wave position covered by the beam carrying the second system message, and the location information of terminals already assigned to the second set of terminals at each adjacent wave position where the shortest distance to the boundary of the current wave position is less than or equal to the first planned distance threshold. The first and second system messages are used by the terminal to determine whether, by initiating initial random access, it will cause inter-terminal shared channel crosslink interference with terminals already assigned to the adjacent second set of terminals, based on the first and second system messages broadcast by the base station, the terminal's own location measurement results, and the first planned distance threshold. If the determination is made that no inter-terminal interference will occur with neighboring terminals in the second set of terminals, the terminal will send the first message using the sequence of the first TDD frame structure. If the determination is made that inter-terminal interference will occur with respect to at least one neighboring terminal in the second set of terminals, the terminal will temporarily refrain from sending the first message. When a first message is scheduled to be sent, and the terminal first reports its location measurement results, the system message includes a step of sending the first message along with the base station using pre-configured time-frequency resources.

[0112] In that case, another feasible method would involve determining whether or not to send the first message, and the method for determining the corresponding frame structure when sending the first message, The TDD frame structure placement information carried in the first system message broadcast by the base station includes placement information corresponding to the first TDD frame structure, and placement information for the frame header offset required to generate the second TDD frame structure. The second system message broadcast by the base station carries the location information of terminals already assigned to the first and second terminal sets at the current wave position covered by the beam carrying the second system message, and the location information of terminals already assigned to the first and second terminal sets where the shortest distance to the boundary of the current wave position at each adjacent wave position is less than or equal to the first planned distance threshold. The first and second system messages are used by a terminal to determine, based on the first and second system messages broadcast by the base station, the terminal's own location measurement results, and the first planned distance threshold, whether initiating initial random access will cause inter-terminal shared channel crosslink interference with adjacent terminals already assigned to the first or second terminal set. If the determination is made that no inter-terminal interference will occur with respect to any adjacent terminals in the first terminal set or the second terminal set, the terminal will send the first message using a sequence of the first or second TDD frame structure. If the determination is made that inter-terminal interference will occur with neighboring terminals in the first set of terminals, but not with neighboring terminals in the second set of terminals, the terminal sends the first message using the sequence of the first TDD frame structure. If the determination is made that inter-terminal interference will occur with neighboring terminals in the second set of terminals, but not with neighboring terminals in the first set of terminals, the terminal sends the first message using a sequence of the second TDD frame structure. If the determination is made that inter-terminal interference will occur between at least one adjacent terminal in the first terminal set and at least one adjacent terminal in the second terminal set, the terminal will temporarily refrain from sending the first message. When a first message is scheduled to be sent, the system includes a step to send the first message, along with the base station, to the terminal when it first reports the location measurement result corresponding to the terminal, using pre-configured time-frequency resources in the system message.

[0113] In practical implementation, the amount of data can be reduced by compressing the geographic location information of terminals that needs to be broadcast by base stations from different angles and / or using different methods before broadcasting. For example, the number of bytes used to represent information for each dimension of a three-dimensional geographic coordinate system can be appropriately reduced, or two-dimensional geographic coordinates can be used instead of three-dimensional geographic coordinates, or a suitable information compression algorithm can be exclusively used.

[0114] In this workaround, terminals that are idle and have not yet initiated initial random access to the base station do not belong to either the first or second set of terminals.

[0115] The following are the countermeasures for the third type of problem that can be avoided as described above.

[0116] If the first message is the first message in which a terminal reports a location measurement result corresponding to that terminal after completing initial random access, the TDD frame structure arrangement information carried in the first system message broadcast by the base station is arrangement information corresponding to the first TDD frame structure, and before sending the first message, the terminal sends and receives messages based on the sequence defined in the first TDD frame structure.

[0117] The first message is the first message that a terminal sends to the base station when it initiates initial random access, and when it first reports a location measurement result corresponding to the terminal, the TDD frame structure arrangement information carried in the first system message, which is sent to the base station and broadcast by the base station, is the arrangement information corresponding to the first TDD frame structure, using pre-allocated time-frequency resources in the system message.

[0118] Regardless of which of the two types of messages the first message falls under, in this application, if any history terminal that has previously accessed a base station and entered a connected state changes to an idle state, the base station will assign the terminal to the first terminal set if it discovers, based on the current location information of the terrestrial wave position covered by the base station and the location information of the terminal stored on the base station side, that the terminal is still in a wave position covered by the base station.

[0119] For any historical terminal that has been registered in the low Earth orbit satellite communication system to which the base station belongs and whose registration is still in effect, the core network transmits the terminal identifier and historical location information to the satellite-borne base station covering the terminal, based on the stored historical location information of the terminal, and the satellite-borne base station covering the terminal then assigns the terminal to the first set of terminals.

[0120] When a base station schedules a terminal that has initiated an initial random access to itself, if it discovers that the terminal belongs to a second terminal set according to the terminal set determination rule, it obtains a fifth distance between the terminal and each idle historical terminal belonging to the first terminal set.

[0121] If any of the fifth distances is greater than or equal to the first planned distance threshold, the terminal is converted to belong to the first terminal set, and scheduling is performed based on the first TDD frame structure.

[0122] Furthermore, the base station needs to receive the location measurement result corresponding to the terminal reported to the base station before the terminal randomly accesses the base station. Here, if the terminal can access the ground network before initiating random access to any satellite-borne base station, the terminal automatically transmits its current location measurement result to a radio access node on the ground network that it can access, and the radio access node then forwards it to a satellite-ground cooperation network element that can exchange information with satellites on the ground network, and the satellite-ground cooperation network element then transmits the terminal's current location measurement result to a satellite-borne base station that currently has coverage of the terminal.

[0123] Similar to interference within a cell, regardless of which specific frame structure design described above is used, no inter-UE interference will occur between any two UEs in the same frame structure's set.

[0124] However, in a set of UEs using the first TDD frame structure, there may be an edge UE in a cell and an edge UE in a set of UEs using the second TDD frame structure within a neighbor cell, where one UE is receiving downlink traffic and the other is transmitting uplink traffic. If the distance between these two edge UEs located in different cells is short, crosslink interference between UEs on shared channels will occur.

[0125] Figure 10 is a schematic diagram of an exemplary embodiment of a satellite communication method based on the time-division duplex TDD frame structure design shown in the present application. This embodiment mainly describes a method for avoiding inter-UE shared channel crosslink interference between "an edge UE in a cell in a UE set using a first TDD frame structure" and "an edge UE in a UE set using a second TDD frame structure within a neighbor cell" by geographical area fencing. As shown in Figure 10, the satellite communication method based on the time-division duplex TDD frame structure design includes the following steps.

[0126] Step S1001: Identify a predetermined set of time-division duplex TDD frame structures corresponding to a base station, wherein the predetermined set of TDD frame structures includes a first TDD frame structure and a second TDD frame structure generated by offsetting the frame header of the first TDD frame structure.

[0127] Regarding the specific implementation method of step S1001, there are a total of three predetermined TDD frame structure design methods. Please refer to the detailed explanation in the relevant section of step S101 in the above embodiment. The explanation will be omitted here.

[0128] Step S1002: In response to receiving the first message transmitted from the terminal, the base station's coverage area is divided into an outer ring and an inner ring based on the base station's coverage area boundary and a first planned distance threshold, and the minimum distance between the boundary line between the outer ring and the inner ring and the base station's coverage area boundary is at least equal to or greater than the first planned distance threshold.

[0129] Centered on the satellite's immovable point, the cell's coverage area is logically divided into an outer ring and an inner ring according to the distance from the satellite's immovable point. Here, the outer ring corresponds to the area extending inward from the boundary line of the cell's coverage area by a distance equal to a first predetermined distance threshold. Figure 11 is a schematic diagram illustrating the division of the base station's coverage area into an outer ring and an inner ring as shown in this application.

[0130] Step S1003: Based on the terminal's location information, it is determined whether the terminal is located within the outer ring of the base station's coverage area.

[0131] Step S1004: If a terminal is located within the outer ring of the base station's coverage area, it is determined that the terminal belongs to the first terminal set, thereby avoiding inter-terminal shared channel crosslink interference between adjacent cells.

[0132] Step S1005: If the terminal is located within the inner circle of the base station's coverage area, the terminal set to which the terminal belongs is further determined, where the terminal set is either the first terminal set or the second terminal set.

[0133] Step S1006: If the terminal belongs to the first set of terminals, scheduling is performed for the terminal based on the first TDD frame structure.

[0134] Step S1007: If the terminal belongs to the second set of terminals, scheduling is performed for the terminal based on the second TDD frame structure.

[0135] In the embodiment of the present invention, when each satellite-borne base station schedules "UEs that have initiated initial random access" based on the geographic location information reported by those UEs, the system is configured such that UEs located within the outer ring of a cell use only the first TDD frame structure, while only UEs located within the inner ring of a cell use two types of frame structures to improve air interface resource utilization. Once all idle UEs are selected using the sequence in the first TDD frame structure and begin initial random access, any "UE performing initial random access operations" located at the edge of a cell will not cause inter-UE interference with any "UEs that have initiated initial random access" located at the edge of a neighbor cell.

[0136] Furthermore, there are three possible forms of cells projected onto the ground by LEO satellites: earth-moving cells, earth-fixed cells (also called gaze cells in some literature), and quasi-earth-fixed cells. An earth-moving cell is a cell that moves with the satellite when projected onto the ground (in this case, the satellite's antenna is generally perpendicular to the ground). An earth-fixed cell is a cell that remains stationary relative to the ground when projected onto the ground (the satellite needs to adjust the antenna's directional angle during its movement to complete coverage of a given area). A quasi-earth-fixed cell is a cell that can provide pointing coverage to a given area on the ground for a certain period of time (i.e., it is in the state of an earth-fixed cell), but after that period, the cell projected onto the ground moves with the satellite (i.e., it becomes an earth-moving cell).

[0137] When a target cell projected by a base station corresponds to a ground mobile cell mode or a ground quasi-geostationary cell mode, if a change in location is detected for each second terminal in the second terminal set, based on its position information, from being located within the inner ring of the base station's coverage area to being located within the outer ring of the base station's coverage area, the terminal set to which it belongs is changed to the first terminal set.

[0138] Furthermore, in this invention, adjacent base stations can coordinate with each other via an inter-satellite link. The specific implementation method is as follows.

[0139] The system receives neighbor terminal location information transmitted from adjacent base stations, and the neighbor terminal location information corresponds to a terminal classified by the adjacent base station into a first terminal set or a second terminal set, or to a terminal classified by the adjacent base station into a first terminal set or a second terminal set, and located at the edge wave position of a corresponding neighbor cell.

[0140] Based on the location information of terminals classified by a base station into a first terminal set or a second terminal set, and neighbor terminal location information, at least one group of terminal equipment for which subband-level frequency division scheduling should be performed is identified, and the group of terminal equipment includes at least one terminal classified by a base station into the first or second terminal set, and at least one adjacent terminal classified by an adjacent base station into the first or second terminal set.

[0141] The specific method for identifying at least one group of terminal devices for which subband-level frequency division scheduling should be performed is as follows: Based on the location information of terminals classified by the base station into a first terminal set or a second terminal set and the location information of neighbor terminals, a fourth distance is calculated between each terminal classified by the base station into a first terminal set or a second terminal set and each terminal classified by an adjacent base station into a first terminal set or a second terminal set; or a fourth distance is calculated between each terminal classified by the base station into a first terminal set or a second terminal set and located at the edge wave position of its own cell and each terminal classified by an adjacent base station into a first terminal set or a second terminal set and located at the edge wave position of a corresponding neighbor cell. For any terminal classified by a base station into a first terminal set or a second terminal set, if the fourth distance between the terminal and an adjacent terminal classified by an adjacent base station into a first terminal set or a second terminal set is less than the first planned distance threshold, the terminal and the adjacent terminal become members of one terminal equipment group. Alternatively, for any terminal classified by a base station into a first terminal set or a second terminal set and located at the edge wave position of its own cell, if the fourth distance between the terminal and an adjacent terminal classified by an adjacent base station into a first terminal set or a second terminal set and located at the edge wave position of a corresponding neighbor cell is less than the first planned distance threshold, the terminal and the adjacent terminal become members of one terminal equipment group.

[0142] In cooperation with adjacent base stations, scheduling is performed for terminals included in a group of terminal devices using a subband-level frequency division scheduling scheme.

[0143] Furthermore, in this application, if the designed frame structure is used, it is necessary to design it adaptively for the SSB transmission system.

[0144] The first design method involves designing without changing the conventional 3GPP NR protocol, and specifically, it is as follows:

[0145] All idle UEs receive a CD-SSB (Cell-defining SSB, i.e., the SSB used to define a cell, which is usually the default SSB that may be used for cell access when SSB is mentioned) at a predetermined SSB transmission timing before initiating initial random access.

[0146] After the UE initiates initial random access, one of the UEs scheduled to use the second TDD frame structure is instructed to perform NCD-SSB (Non-cell-defining SSB, i.e., SSB that cannot be used to define cells) listening to complete the required RRM, RLM, and BFD measurements.

[0147] The base station applies a similar frame header offset to the NCD-SSB transmission. Here, the frame header offset amount corresponding to the NCD-SSB is the same as the frame header offset amount corresponding to the second TDD frame structure, and each terminal in the second terminal set receives the NCD-SSB and completes the required radio link measurement.

[0148] The NCD-SSB period is set to be greater than or equal to the CD-SSB period (the setting must conform to the 3GPP NR protocol).

[0149] The reason NCD-SSB is called an "SSB that cannot be used to define cells" is that MIB messages in NCD-SSB do not contain information about SIB1 (specifically, MIB messages in NCD-SSB do not include CORESET#0 and Type0-PDCCH CSS for the UE to receive / decode SIB1 messages).

[0150] The Type 2 design method involves a modified version of the conventional 3GPP NR protocol, specifically as follows:

[0151] In the design of the highly efficient TDD frame structure described in this text, regardless of the specific design details, the frame header offset is the sum of the number of DL time slots and the number of UL time slots in the first TDD frame structure. If we denote the "sum of the number of DL time slots and the number of UL time slots in the first TDD frame structure" as M, the designed changes are explained as follows. Counting the frame header of the first TDD frame structure as the temporal starting point, the satellite-borne base station transmits CD-SSB in the 1st time slot, the 2nd time slot, the M+1 time slot, and the M+2 time slot. Figure 12 is a schematic diagram for determining the CD-SSB transmission time slots using the design method of the first type of frame structure group as an example, where M is equal to the number of GP time slots N. Based on the specific frame structure example shown in Figure 12 (frame period of 10ms, N=10), the designed changes to the SSB transmission method are explained as follows. If the SSB transmission method designated as case C in the 3GPP 5G protocol is used as the basis for the design, then according to the 3GPP 5G protocol, CD-SSB is to transmit in the first four time slots at every 20ms time interval (i.e., every two radio frames). Here, in accordance with the proposed that "the base station schedules some of the UEs within the cell in each of the first and second TDD frame structures," CD-SSB can be modified to transmit in the first two time slots, the M+1 time slot (11th time slot), and the M+2 time slot (12th time slot) at every 20ms time interval.

[0152] Furthermore, this application also proposes optimizing the "time to first report GNSS measurement results." Specifically, this is explained below.

[0153] According to the current version of the 3GPP protocol definition, after initial random access is complete, the UE completes individual identification, rights verification, and encryption by communicating with the core network via NAS messages, and then completes authentication of the security mode and retrieval and reporting of GNSS measurement results through air interface interaction, followed by retrieval and reporting of UE capabilities. In other words, an idle UE needs to transmit several other messages after the initial random access process is complete (i.e., after the transmission of Msg5 is complete), and only then does it report GNSS measurement results (i.e., its own geographical location information) for the first time.

[0154] To further improve the effectiveness of interference avoidance through geographical separation (especially the effect of geographical separation in avoiding inter-UE interference given to the UE that initiated the initial random access when the first random access message from the UE performing the initial random access operation is affected), it is recommended to include the terminal's GNSS measurement results in the first message sent when an idle UE performs an initial random access (i.e., Msg1 / MsgA) (i.e., advance the time when the GNSS measurement results are first reported to the time when the first message in the initial random access process is sent).

[0155] When the first message in the initial random access process is Msg1 (i.e., a four-stage random access is used as the initial random access), the method in which the GNSS measurement results are carried in Msg1 along with the PRACH preamble sequence and transmitted to the base station may be described by referring to the method in two-stage random access where "PUSCH is carried in MsgA along with the PRACH preamble sequence and transmitted to the base station." In other words, the GNSS measurement results are carried in Msg1 along with the PRACH preamble sequence and transmitted to the base station, according to the pre-allocated time-frequency resources of the broadcast in the system message (i.e., grant-free scheduling).

[0156] Furthermore, if the first message in the initial random access process is MsgA (i.e., two-stage random access was used as the initial random access), the GNSS measurement result only needs to be considered as a new addition to a part of PUSCH in MsgA.

[0157] Figure 13 is a schematic diagram of an exemplary embodiment of a satellite communication method based on the time-division duplex TDD frame structure design shown in this application. This satellite communication method based on the time-division duplex TDD frame structure design is used in a user terminal UE and includes the following steps.

[0158] Step S1301: Send the first message corresponding to the terminal to the base station.

[0159] Selectively, the first message is the message in which the terminal reports its location measurement result for the first time after completing the initial random access.

[0160] Selectively, the first message is the initial message that a terminal sends to the base station when it initiates initial random access.

[0161] The user terminal UE sends a first message corresponding to the terminal to the base station. In response, the base station, after receiving the first message from the terminal, determines the terminal set to which the terminal belongs according to a predetermined first rule.

[0162] Step S1302: The base station accepts scheduling to a terminal based on a first TDD frame structure or a second TDD frame structure, where the second TDD frame structure is generated by offsetting the frame header relative to the first TDD frame structure.

[0163] If a terminal belongs to the first set of terminals, it accepts scheduling by the base station based on the first TDD frame structure.

[0164] If a terminal belongs to the second set of terminals, it accepts scheduling by the base station based on the second TDD frame structure.

[0165] Here, the first set of terminals is the set that has been called to be constructed using terminals of the first TDD frame structure.

[0166] Here, the second set of terminals is the set that has been called to be constructed using terminals of the second TDD frame structure.

[0167] In the embodiment of the present invention, within a single cell, based on classification and scheduling of UEs by a satellite-borne base station, some ground UEs use a first TTD frame structure, while other ground UEs use a second TDD frame structure as their TDD structure, which is obtained by offsetting the frame header of the first TTD frame structure. Furthermore, all (or some) DL and UL time slots in the second TDD frame structure correspond to the GP time slots in the first TDD frame structure (i.e., they occur at the same time), and simultaneously, all (or some) DL and UL time slots in the first TDD frame structure naturally correspond to the GP time slots in the second TDD frame structure. As a result, the satellite-borne base station can communicate with some UEs even when communication with some UEs enters a waiting period (i.e., is in the GP period in the corresponding frame structure), thereby improving the overall air interface resource utilization rate of the system.

[0168] Selectively, the first message is the message in which the terminal first reports the location measurement result corresponding to the terminal after completing the initial random access, where the TDD frame structure arrangement information carried in the first system message broadcast by the base station is the arrangement information corresponding to the first TDD frame structure, where, after the base station receives the first message of all messages transmitted by the terminal before the first message is sent, if the terminal does not yet belong to the first or second terminal set at that time, it is determined that the terminal belongs to the first terminal set. Here, the reporting time of the message for first reporting the location measurement result corresponding to the terminal is after the terminal has completed the initial random access, and has completed individual identification, access verification and encryption with the core network by the Non-Access Layer (NAS), and has completed the security mode control process with the base station by air interface interaction.

[0169] Selectively, the first message is the first message that a terminal sends to the base station when it initiates initial random access, and when it first reports a location measurement result corresponding to the terminal, it sends the first message along with the first message to the base station using pre-allocated time-frequency resources in the system message, and the TDD frame structure arrangement information carried in the first system message broadcast by the base station is arrangement information corresponding to the first TDD frame structure, and the terminal sends the first message using the sequence of the first TDD frame structure.

[0170] The first message is the first message a terminal sends to the base station when it initiates initial random access. The method for determining whether to send the first message and the corresponding frame structure when sending the first message is as follows: The TDD frame structure placement information carried in the first system message broadcast by the base station is the placement information corresponding to the first TDD frame structure. The second system message broadcast by the base station carries the location information of terminals already assigned to the second set of terminals at the current wave position covered by the beam having the second system message, and the location information of terminals already assigned to the second set of terminals where the shortest distance to the boundary of the current wave position at each adjacent wave position is less than or equal to the first planned distance threshold. Based on a first system message to be sent, a second system message, the terminal's own position measurement result, and a first planned distance threshold, the system now determines whether initiating initial random access will cause inter-terminal shared channel crosslink interference to terminals already assigned to an adjacent second terminal set. If it is determined that no inter-terminal interference will occur to adjacent terminals in the second terminal set, the terminal transmits the first message using a sequence of first TDD frame structures. If it is determined that inter-terminal interference will occur to at least one adjacent terminal in the second terminal set, the terminal temporarily refrains from transmitting the first message. When the first position measurement result corresponding to the terminal is reported for the first time, the system includes the step of transmitting the first message along with the first message to the base station using pre-allocated time-frequency resources in the system message.

[0171] If the first message is the first message a terminal sends to the base station when it initiates initial random access, the method for determining whether to send the first message and the corresponding frame structure when the first message is sent includes: receiving a first system message broadcast by the base station, where the TDD frame structure placement information carried in the first system message broadcast by the base station includes placement information corresponding to the first TDD frame structure and placement information for the frame header offset required to generate the second TDD frame structure; receiving a second system message broadcast by the base station, where the second system message broadcast by the base station includes the location information of terminals already assigned to the first and second terminal sets at the current wave position covered by the beam having the second system message, and the location information of terminals already assigned to the first and second terminal sets where the shortest distance to the boundary of the current wave position at each adjacent wave position is less than or equal to a first planned distance threshold. When a report is received, the terminal, based on the first system message broadcast by the base station, the second system message, the terminal's own position measurement result, and the first planned distance threshold, determines whether initiating initial random access will cause inter-terminal shared channel crosslink interference to adjacent terminals already assigned to the first or second terminal set. If it is determined that no inter-terminal interference will occur to any adjacent terminals in the first or second terminal set, the terminal sends a first message using a sequence of the first or second TDD frame structure, causing inter-terminal interference to adjacent terminals in the first terminal set. However, if it is determined that no inter-terminal interference will occur to adjacent terminals in the second terminal set, the terminal sends the first message using a sequence of the first TDD frame structure, causing inter-terminal interference to adjacent terminals in the second terminal set. However, if it is determined that no inter-terminal interference will occur to adjacent terminals in the first terminal set, the terminal...The system includes the steps of: transmitting a first message using a second TDD frame structure sequence; if it is determined that this would cause inter-terminal interference to at least one adjacent terminal in the first terminal set and at least one adjacent terminal in the second terminal set, the terminal temporarily refrains from transmitting the first message; and, when the terminal is scheduled to transmit the first message and reports its corresponding position measurement result for the first time, transmitting the first message along with the first message to the base station using pre-allocated time-frequency resources in the system message.

[0172] Furthermore, the base station, after avoiding any possible inter-terminal shared channel crosslink interference between terminals using several different frame structures through a subband-level frequency division scheduling scheme, performs interference rejection on the inter-terminal shared channel subband crosslink interference that remains on the terminal side despite subband-level frequency division scheduling, using one or more of the following methods: spatial domain interference rejection, analog domain interference rejection, and digital domain interference rejection.

[0173] Figure 14 is a schematic diagram of the structure of a satellite communication device based on the time-division duplex TDD frame structure design proposed in the embodiment of the present application.

[0174] As shown in Figure 14, the satellite communication device 1400 based on the time-division duplex TDD frame structure design is applied to network equipment and includes a specific module 1401, a decision module 1402, a first scheduling module 1403, and a second scheduling module 1404.

[0175] Here, the specific module 1401 is configured to identify a predetermined set of time-division duplex TDD frame structures corresponding to a base station, wherein the predetermined set of TDD frame structures includes a first TDD frame structure and a second TDD frame structure generated by offsetting the frame header relative to the first TDD frame structure.

[0176] The decision module 1402 is configured to determine the set of terminals to which a terminal belongs in response to receiving a first message sent from a terminal, where the set of terminals is either the first set of terminals or the second set of terminals.

[0177] The first scheduling module 1403 is configured to perform scheduling for terminals based on a first TDD frame structure if the terminal belongs to a first set of terminals.

[0178] The second scheduling module 1404 is configured to perform scheduling for terminals based on a second TDD frame structure if the terminal belongs to a second set of terminals.

[0179] Figure 15 is a schematic diagram of the structure of a satellite communication device based on another time-division duplex TDD frame structure design proposed in the embodiment of the present application.

[0180] As shown in Figure 15, the satellite communication device 1500 based on the time-division duplex TDD frame structure design is applied to a user terminal (UE) and includes a transmission module 1501 and a scheduling reception module 1502.

[0181] The transmitting module 1501 was positioned to send a first message corresponding to the terminal to the base station.

[0182] The scheduling reception module 1502 is used in the module and is configured to receive scheduling requests from the base station to a terminal based on a first TDD frame structure or a second TDD frame structure, where the second TDD frame structure is generated by offsetting the frame header relative to the first TDD frame structure.

[0183] According to embodiments of the present application, a communication device and a readable storage medium are further provided.

[0184] As shown in Figure 16, the communication device comprises one or more processors 1601, memory 1602, and interfaces including high-speed and low-speed interfaces for connecting each component. Each component is connected to one another by different buses and mounted on a common main plate, or may be mounted in other ways as needed. The processors process commands executed within the communication device, and these commands are stored in memory or on memory so that graphical information of a GUI is displayed on an external input / output device (e.g., a display device coupled to the interface). In other embodiments, multiple processors and / or multiple buses and multiple memories, along with multiple memories, can be used as needed. Similarly, multiple communication devices can be connected, with each device providing some of the necessary operations (e.g., functioning as a server array, a set of blade servers, or a multiprocessor system). Figure 16 shows a single processor 1601 as an example.

[0185] Memory 1602 is, in other words, a non-temporary computer-readable storage medium provided by the present invention. Here, the memory stores commands that can be executed by at least one processor to cause the satellite communication method based on the time-division duplex TDD frame structure design provided by the present invention to be executed by the at least one processor. The non-temporary computer-readable storage medium in the present invention stores computer commands that cause a computer to execute the satellite communication method based on the time-division duplex TDD frame structure design provided by the present invention.

[0186] Memory 1602 may be used as a non-temporary computer-readable storage medium to store non-temporary software programs, non-temporary computer-executable programs and modules, for example, program commands / modules corresponding to the satellite communication method based on the time-division duplex TDD frame structure design in the embodiment of the present application. The processor 1601 executes various types of functional applications and data processing in the processor by running the non-temporary software programs, commands and modules stored in memory 1602, that is, to realize the satellite communication method based on the time-division duplex TDD frame structure design in the above embodiment of the method.

[0187] Memory 1602 may include a program storage area capable of storing application programs necessary for the operating system and at least one function, and a data storage area capable of storing data created in accordance with the use of positioning communication equipment. Memory 1602 may also include high-speed random access memory, and may further include non-temporary memory such as at least one disk memory, flash memory, or other non-temporary solid memory. Selectively, memory 1200 may be a memory remotely provided to the processor 1601. These remote memories can be connected to positioning communication equipment via a network. Examples of the above network may include, but are not limited to, the Internet, an enterprise intranet, a local area network, a mobile communication network, and combinations thereof.

[0188] The communication equipment may further include an input device 1603 and an output device 1604. The processor 1601, memory 1602, input device 1603, and output device 1604 may be connected by a bus or other means. Figure 16 shows an example of a bus connection.

[0189] The input device 1603 can receive input numerical or character information and can generate key signal inputs related to user settings and function control of the positioning communication device. Examples of input devices include touchscreens, keypads, mice, trackpads, touchpads, indicator sticks, one or more mouse buttons, trackballs, and joysticks. The output device 1604 may include a display device, an auxiliary lighting device (e.g., LEDs), and a haptic feedback device (e.g., a vibration motor). The display device may include, but is not limited to, a liquid crystal display (LCD), a light-emitting diode (LED) display, and a plasma display. In some embodiments, the display device may be a touchscreen.

[0190] Various embodiments of the systems and technologies described herein may be implemented in digital electronic circuit systems, integrated circuit systems, application-specific integrated circuits (ASICs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may be implemented in one or more computer programs. The one or more computer programs may be executed and / or interpreted in a programmable system including at least one programmable processor. The programmable processor may be a dedicated or general-purpose programmable processor and may receive data and commands from a storage system, at least one input device, and at least one output device, and may transmit data and commands to the storage system, the at least one input device, and the at least one output device.

[0191] These computer programs (also called programs, software, software applications, or code) include machine instructions for a programmable processor, and may be implemented using high-level process and / or object-oriented programming languages ​​and / or assembly / machine languages. As used herein, “machine-readable medium” and “computer-readable medium” refer to materials for providing machine instructions and / or data to any computer program product, device, and / or apparatus (e.g., magnetic disks, optical disks, programmable logic devices (PLDs)) of a programmable processor, and include machine-readable medium that accepts machine instructions as machine-readable signals. The term “machine-readable signal” refers to materials for providing machine instructions and / or data to any signal of a programmable processor.

[0192] To provide user interaction, the systems and techniques described herein may be implemented on a computer. The computer may include a display device for displaying information to the user (e.g., a CRT (Cathode Ray Tube) or LCD (Liquid Crystal Display) monitor), a keyboard, and a pointing device (e.g., a mouse or trackball), allowing the user to provide input to the computer via the keyboard and pointing device. Other types of devices may be used to provide user interaction. For example, the feedback provided to the user may be any form of sensor feedback (e.g., visual feedback, auditory feedback, or haptic feedback), and input from the user may be received in any form (acoustic input, voice input, or haptic input).

[0193] The systems and technologies described herein can be implemented in a computing system including backend components (e.g., as a data server), a computing system including middleware components (e.g., an application server), a computing system including frontend components (e.g., a user computer having a graphical user interface or a web browser, through which the user can interact with embodiments of the systems and technologies described herein), or in a computing system including any combination of such backend components, middleware components, and frontend components. Components in the system may be connected to one another by communication of digital data in any form or medium (e.g., a communication network). Examples of communication networks include local area networks (LANs), wide area networks (WANs), and the internet.

[0194] A computer system may include user terminals and servers. User terminals and servers are typically geographically separated and usually interact via a communication network. The user terminal-server relationship is created by executing computer programs on the corresponding computers that have a user terminal-server relationship with each other.

[0195] It should be understood that the steps can be reordered, added, or deleted through the various forms of processes described above. For example, each step described herein may be performed in parallel, in a specific order, or according to different priorities, as long as the desired results of the proposed techniques disclosed herein are achieved. The text hereof does not limit this in any particular way.

Claims

1. A satellite communication method based on a time-division duplex TDD frame structure design used in network equipment, A step of identifying a predetermined group of time-division duplex TDD frame structures corresponding to a base station, wherein the predetermined group of TDD frame structures includes a first TDD frame structure and a second TDD frame structure generated by offsetting the frame header with respect to the first TDD frame structure. A step of determining the set of terminals to which the terminal belongs in response to receiving a first message transmitted from the terminal, wherein the set of terminals is either a first set of terminals or a second set of terminals. If the terminal belongs to the first set of terminals, the steps include: scheduling the terminal based on the first TDD frame structure; If the terminal belongs to the second set of terminals, the steps include: performing scheduling for the terminal based on the second TDD frame structure; A satellite communication method based on a time-division duplex TDD frame structure design, characterized by including the following:

2. The method for obtaining the predetermined TDD frame structure group is as follows: A step of installing the first TDD frame structure, wherein the number of protection interval (GP) time slots of the first TDD frame structure is N, and the sum of the number of downlink (DL) time slots and the number of uplink (UL) time slots in the first TDD frame structure is equal to N. A step of obtaining the second TDD frame structure by offsetting the frame header of the first TDD frame structure by N time slots, wherein all DL time slots and all UL time slots in the second TDD frame structure correspond to all GP time slots in the first TDD frame structure, The method according to claim 1, comprising the step of generating the predetermined group of TDD frame structures based on the first TDD frame structure and the second TDD frame structure.

3. The method for obtaining the predetermined TDD frame structure group is as follows: A step of setting up the first TDD frame structure, wherein the number of GP time slots in the first TDD frame structure is N, and the sum of the number of DL time slots and the number of UL time slots in the first TDD frame structure is less than N. A step of obtaining the second TDD frame structure by offsetting the frame header of the first TDD frame structure, wherein all DL time slots and all UL time slots in the second TDD frame structure correspond to some GP time slots in the first TDD frame structure, The steps include generating the predetermined group of TDD frame structures based on the first TDD frame structure and the second TDD frame structure, The method according to claim 1, characterized by including the following:

4. The method for obtaining the predetermined TDD frame structure group is as follows: A step of setting up the first TDD frame structure, wherein the number of GP time slots in the first TDD frame structure is N, and the sum of the number of DL time slots and the number of UL time slots in the first TDD frame structure is greater than N. A step of obtaining the second TDD frame structure by offsetting the frame header of the first TDD frame structure, wherein some of the time slots among all DL time slots and all UL time slots in the second TDD frame structure correspond to all GP time slots in the first TDD frame structure, and collision slots exist between the first TDD frame structure and the second TDD frame structure. The steps include generating the predetermined group of TDD frame structures based on the first TDD frame structure and the second TDD frame structure, The method according to claim 1, characterized by including the following:

5. The collision slots located in the first TDD frame structure are muted, or The method according to 4, further comprising the step of muting the collision slots located in the second TDD frame structure.

6. The method according to claim 4, further comprising the step of performing subband full-duplex frequency division multiplexing with subband granularity using subband full-duplex technology for the reception of uplink data from terminals scheduled by the base station to use one of the first and second TDD frame structures, and for the transmission of downlink data from terminals scheduled by the base station to use the other of the first and second TDD frame structures.

7. For the reception of uplink data from a terminal that uses one of the first and second TDD frame structures, scheduled by the base station, and for the transmission of downlink data from a terminal that uses the other of the first and second TDD frame structures, scheduled by the base station, frequency division multiplexing with subband granularity is performed using subband full-duplex technology, The invention further includes performing interference rejection on two types of inter-subband interference remaining on the network side, including base station self-interference and inter-subband crosslink interference on shared channels between base stations, using one or more methods from among a spatial interference rejection method, an analog interference rejection method, and a digital interference rejection method. The method according to feature 6.

8. The method according to any one of claims 1 to 7, further comprising the step of performing interference avoidance by a subband-level frequency division scheduling scheme when inter-terminal shared channel crosslink interference exists between any first terminal belonging to the first terminal set and any second terminal belonging to the second terminal set.

9. The step of determining the set of terminals to which the terminal belongs in response to receiving a first message sent from the terminal is: A step of obtaining a first set of location information corresponding to each first terminal in the first set of terminals, wherein the first terminal and the base station are connected, A step of obtaining a second set of location information corresponding to each second terminal in the second set of terminals, wherein the second terminal and the base station are connected, The steps include: obtaining terminal location information corresponding to the aforementioned terminal; A step of determining the terminal set to which the terminal belongs based on the first set of location information, the second set of location information, and the terminal location information, The method according to any one of claims 1 to 5, characterized in that it includes

10. The step of determining the terminal set to which the terminal belongs, based on the first set of location information, the second set of location information, and the terminal location information, is: A step of obtaining the minimum distance among the distances between the terminal and each first terminal in the first terminal set as the first distance, based on the first set of location information and the terminal location information, A step of obtaining the minimum distance among the distances between the terminal and each second terminal in the second terminal set as the second distance, based on the second set of location information and the terminal location information, The steps include comparing the first distance and the second distance with a first planned distance threshold to determine the set of terminals to which the terminal belongs, The method according to 9, characterized in that it includes

11. The step of comparing the first distance and the second distance with a first planned distance threshold to determine the set of terminals to which the terminal belongs is: The steps include determining whether the terminal belongs to the first terminal set or the second terminal set if both the first distance and the second distance are greater than or equal to the first planned distance threshold, The step of determining that the terminal belongs to the first set of terminals when the first distance is greater than or equal to the first planned distance threshold and the second distance is less than the first planned distance threshold, The step of determining that the terminal belongs to the second set of terminals when the first distance is less than the first planned distance threshold and the second distance is equal to or greater than the first planned distance threshold, If both the first distance and the second distance are less than the first planned distance threshold, the step of determining the terminal set to which the terminal belongs according to a predetermined terminal set determination rule, The method according to the present invention, characterized by including the following:

12. The step of determining the terminal set to which the terminal belongs, according to predetermined terminal set determination rules, is: Determine the terminal set to which the terminal belongs according to the terminal quantity balancing rules within the first terminal set and the second terminal set, or The method according to 11, characterized in that it includes, but is not limited to, determining the set of terminals to which the terminal belongs according to a rule for randomly selecting one of them.

13. If both the first distance and the second distance are less than the first planned distance threshold, then, after determining the terminal set to which the terminal belongs according to a predetermined terminal set determination rule, If the terminal set to which the terminal belongs is a second terminal set, the first terminal subset is obtained based on the first location information set and the terminal location information, such that the distance value to the terminal in the first terminal set is less than the first planned distance threshold, and shared channel crosslink interference between the terminal and each terminal in the first terminal subset is avoided by a subband level frequency division scheduling method, and The method according to 12, further comprising the step of, if the set of terminals to which the terminal belongs is the first set of terminals, obtaining a second set of terminals in the second set of terminals whose distance value to the terminal in the second set of terminals is less than the first planned distance threshold, based on the second set of location information and the terminal location information, and avoiding shared channel crosslink interference between the terminal and each terminal in the second set of terminals by a subband level frequency division scheduling scheme.

14. The method according to claim 13, further comprising the step of, in response to receiving location update information reported by any first terminal in the first terminal set or any second terminal in the second terminal set, determining a terminal set corresponding to the terminal reporting the location update information, based on the location update information, in accordance with the steps described in claims 9 to 12.

15. The method further includes the step of determining the set of terminals corresponding to the terminals reporting the location update information based on the location update information, by changing the set of terminals to which at least one terminal that did not report the location update information in the first set of terminals and the second set of terminals belongs, thereby minimizing the number of terminals that need to avoid inter-terminal shared channel crosslink interference by the subband level frequency division scheduling scheme in the updated first set of terminals and the second set of terminals. The method according to feature 14.

16. The step of determining the set of terminals to which the terminal belongs in response to receiving a first message sent from the terminal is: A step of dividing the base station's coverage area into an outer ring and an inner ring based on the base station's coverage area boundary and a first planned distance threshold, wherein the minimum distance between the boundary line between the outer ring and the inner ring and the base station's coverage area boundary is at least equal to or greater than the first planned distance threshold, A step of determining whether the terminal is located within the outer ring of the base station's coverage area based on the terminal location information of the terminal, If the terminal is located within the outer ring of the base station's coverage area, the terminal is determined to belong to the first terminal set, thereby avoiding inter-terminal shared channel crosslink interference between adjacent cells. If the terminal is located within the inner ring of the coverage area of ​​the base station, the method includes the step of determining the terminal set to which the terminal belongs, according to the method of any one of claims 1 to 12, wherein the terminal set is either a first terminal set or a second terminal set. The method according to any one of claims 1 to 15, characterized by...

17. If the target cell projected by the base station corresponds to a ground mobile cell mode or a ground quasi-stationary cell mode, the further step includes, for each second terminal in the second terminal set, detecting, based on its location information, a change in its position from being located within the inner ring of the base station's coverage area to being located within the outer ring of the base station's coverage area, changing the terminal set to which it belongs to the first terminal set. The method according to 16, characterized by...

18. A step of receiving neighbor terminal location information transmitted from an adjacent base station, wherein the neighbor terminal location information is location information corresponding to a terminal classified by the adjacent base station into a first terminal set or a second terminal set, or location information corresponding to a terminal classified by the adjacent base station into a first terminal set or a second terminal set and located at the edge wave position of a corresponding neighbor cell, A step of identifying at least one group of terminal equipment on which subband-level frequency division scheduling should be performed, based on the location information of terminals classified by the base station into a first terminal group or a second terminal group and the neighbor terminal location information, wherein the group of terminal equipment includes at least one terminal classified by the base station into a first or second terminal group, and at least one adjacent terminal classified by the adjacent base station into a first or second terminal group; The steps include: working in cooperation with the adjacent base stations to schedule terminals included in the group of terminal equipment using a subband-level frequency division scheduling method; The method according to any one of claims 1 to 15, further comprising:

19. The step of identifying at least one group of terminal devices for which subband-level frequency division scheduling should be performed, based on the location information of terminals classified by the base station into a first terminal group or a second terminal group and the neighbor terminal location information, A step of calculating a fourth distance between each terminal classified into the first terminal set or the second terminal set by the base station and each terminal classified into the first terminal set or the second terminal set by the adjacent base station, based on the location information of the terminals classified into the first terminal set or the second terminal set by the base station and the neighbor terminal location information, or a step of calculating a fourth distance between each terminal classified into the first terminal set or the second terminal set by the base station and located at the edge wave position of its own cell and each terminal classified into the first terminal set or the second terminal set by the adjacent base station and located at the edge wave position of a corresponding neighbor cell, and The steps include: for any terminal classified by the base station into a first terminal set or a second terminal set, if the fourth distance between the terminal and any adjacent terminal classified by the adjacent base station into a first terminal set or a second terminal set is less than the first planned distance threshold, the terminal and the adjacent terminal become members of a single terminal equipment group; or for any terminal classified by the base station into a first terminal set or a second terminal set and located at the edge wave position of its own cell, if the fourth distance between the terminal and any adjacent terminal classified by the adjacent base station into a first terminal set or a second terminal set and located at the edge wave position of a corresponding neighbor cell is less than the first planned distance threshold, the terminal and the adjacent terminal become members of a single terminal equipment group. The method according to the present invention, characterized by the present invention.

20. The process further includes the step of performing a frame header offset for synchronous and broadcast signal blocks (NCD-SSB) that cannot be used to define a cell, The frame header offset amount corresponding to the NCD-SSB is the same as the frame header offset amount corresponding to the second TDD frame structure. The method according to any one of claims 1 to 19, characterized in that each terminal in the second terminal set receives NCD-SSB and completes the required wireless link measurement.

21. The steps include: denoting M as the sum of the number of DL time slots and the number of UL time slots in the first TDD frame structure; Counting the frame header of the first TDD frame structure as the temporal starting point, the further steps include transmitting CD-SSB in the first time slot, the second time slot, the M+1 time slot, and the M+2 time slot. The method according to any one of claims 1 to 19, characterized by...

22. The step of determining the set of terminals to which the terminal belongs in response to receiving a first message sent from the terminal is: The method according to claim 1, further comprising the step of determining the terminal set to which the terminal belongs in accordance with predetermined terminal set determination rules, in response to receiving a first message transmitted from the terminal.

23. The first message is a message in which the terminal reports the location measurement result corresponding to the terminal for the first time after completing the initial random access, and the method is as follows: The TDD frame structure arrangement information carried in the first system message broadcast by the base station is arrangement information corresponding to the first TDD frame structure, and further includes the step of determining that the terminal belongs to the first terminal set if, after the first message of all messages transmitted by the terminal before transmitting the first message has been received by the base station, the terminal does not yet belong to the first terminal set or the second terminal set at that time. The reporting time of the message for the first location measurement result corresponding to the terminal is after the terminal has completed initial random access, completed individual identification, access verification, and encryption with the core network by the Non-Access Layer (NAS), and completed the security mode control process with the base station through air interface interaction. The method according to feature 1.

24. The first message is the first message that the terminal sends to the base station when it initiates initial random access, and the method is, When reporting a location measurement result corresponding to the terminal for the first time, the system further includes the step of transmitting it to the base station along with the first message using pre-configured time-frequency resources in the system message, The TDD frame structure arrangement information carried in the first system message broadcast by the base station is arrangement information corresponding to the first TDD frame structure, and the terminal transmits the first message using the sequence of the first TDD frame structure. The method according to feature 1.

25. When the base station performs downlink time-frequency resource scheduling for any terminal belonging to the second set of terminals, it takes the steps of determining the slot index of a UL time slot arranged to transmit a random access preamble sequence in the first TDD frame structure, The steps include obtaining the slot indices of a plurality of consecutive DL time slots in a second TDD frame structure, wherein the distance to the UL time slots arranged to transmit the random access preamble sequence in the first TDD frame structure is within a predetermined slot range, The method further includes the step of performing frequency domain resource scheduling for each DL time slot among a plurality of consecutive DL time slots within a predetermined slot range in the second TDD frame structure, together with air interface resources arranged to perform initial random access to terminals in the first terminal set, thereby realizing subband level frequency division scheduling. The method according to 23 or 24, characterized by the features described above.

26. The first message is the first message that the terminal sends to the base station when it initiates initial random access. In the method for determining whether or not to send the first message, and for determining the corresponding frame structure when the first message is sent, The TDD frame structure arrangement information carried in the first system message broadcast by the base station is arrangement information corresponding to the first TDD frame structure. The second system message broadcast by the base station carries the location information of terminals already assigned to the second set of terminals at the current wave position covered by the beam carrying the second system message, and the location information of terminals already assigned to the second set of terminals at each adjacent wave position, the shortest distance from the boundary of the current wave position being less than or equal to the first planned distance threshold. The first system message and the second system message are for determining whether the terminal, by initiating initial random access, will cause inter-terminal shared channel crosslink interference with terminals already assigned to an adjacent second set of terminals, based on the first system message broadcast by the base station, the second system message, the terminal's own position measurement result, and a first planned distance threshold. If, as a result of the determination, it is determined that no inter-terminal interference will occur with respect to adjacent terminals in the second set of terminals, the terminal transmits the first message using the sequence of the first TDD frame structure. If, as a result of the determination, it is determined that inter-terminal interference will occur with respect to at least one adjacent terminal in the second set of terminals, the terminal will temporarily refrain from sending the first message. The method according to claim 1, characterized in that, when the first message is scheduled to be sent, the location measurement result corresponding to the terminal is reported for the first time, the system message is transmitted to the base station together with the first message using pre-allocated time-frequency resources.

27. The first message is the first message that the terminal sends to the base station when it initiates initial random access. In the method for determining whether or not to send the first message, and for determining the corresponding frame structure when the first message is sent, The TDD frame structure arrangement information carried in the first system message broadcast by the base station includes arrangement information corresponding to the first TDD frame structure and arrangement information for the frame header offset required to generate the second TDD frame structure. The second system message broadcast by the base station carries the location information of terminals already assigned to the first and second terminal sets at the current wave position covered by the beam carrying the second system message, and the location information of terminals already assigned to the first and second terminal sets where the shortest distance to the boundary of the current wave position at each adjacent wave position is less than or equal to a first planned distance threshold. The first system message and the second system message are for determining whether the terminal, by initiating initial random access, will cause inter-terminal shared channel crosslink interference with terminals already assigned to adjacent first or second terminal sets, based on the first system message broadcast by the base station, the second system message, the terminal's own position measurement result, and a first planned distance threshold. If, as a result of the determination, it is determined that no inter-terminal interference will occur with respect to any adjacent terminals in the first terminal set and the second terminal set, the terminal transmits the first message using a sequence of the first TDD frame structure or the second TDD frame structure. If the determination is made that inter-terminal interference will occur with neighboring terminals in the first terminal set, but not with neighboring terminals in the second terminal set, the terminal transmits the first message using the sequence of the first TDD frame structure. If the determination is made that inter-terminal interference will occur with respect to adjacent terminals in the second set of terminals, but not with respect to adjacent terminals in the first set of terminals, the terminal transmits the first message using a sequence of the second TDD frame structure. If, as a result of the determination, it is determined that inter-terminal interference will occur between at least one adjacent terminal in the first terminal set and at least one adjacent terminal in the second terminal set, the terminal will temporarily refrain from sending the first message. When the first message is scheduled to be sent, and the terminal reports its location measurement result for the first time, the system message includes the step of transmitting the first message, along with the location measurement result, to the base station using pre-configured time-frequency resources in the system message. The method according to feature 1.

28. The method according to any one of claims 25 to 27, characterized in that terminals that are in an idle state and have not yet initiated initial random access to the base station do not belong to either the first terminal set or the second terminal set.

29. If any of the history terminals that have previously accessed the base station and entered a connected state changes to an idle state, the base station, based on the current location information of the terrestrial wave position covered by itself and the location information of the terminal stored on the base station side, discovers that the terminal is still in a wave position covered by the base station, and then assigns the terminal to the first set of terminals. For any history terminal that has been registered in the low Earth orbit satellite communication system to which the base station belongs and whose registration is still in effect, the core network transmits the identifier of the terminal and the history location information of the terminal to the satellite-borne base station covering the terminal, and the satellite-borne base station covering the terminal then assigns the terminal to the first set of terminals. When the base station performs scheduling for a terminal that has initiated an initial random access to itself, if it discovers that the terminal belongs to a second terminal set according to the terminal set determination rule, it takes the step of obtaining a fifth distance between the terminal and each idle historical terminal belonging to the first terminal set. If any of the fifth distances is greater than or equal to the first planned distance threshold, the terminal is converted to belong to the first set of terminals, and scheduling is performed based on the first TDD frame structure. The method according to 23 or 24, further comprising:

30. The step further includes receiving a location measurement result corresponding to the terminal reported to the base station before the terminal randomly accesses the base station, The method according to 29, characterized in that, before the terminal initiates random access to any satellite-borne base station, if the terminal can access the ground network, the terminal automatically transmits its current location measurement result to a radio access node in the ground network that it can access, the radio access node then forwards it to a satellite-ground cooperation network element in the ground network that can exchange information with satellites, and the satellite-ground cooperation network element then transmits the terminal's current location measurement result to a satellite-borne base station that can currently cover the terminal.

31. A satellite communication method based on a time-division duplex TDD frame structure design, used in a user terminal (UE), The steps include sending a first message corresponding to the terminal to the base station, The step includes receiving scheduling to the terminal based on a first TDD frame structure or a second TDD frame structure from the base station, The second TDD frame structure is a satellite communication method based on a time-division duplex TDD frame structure design, generated by offsetting the frame header relative to the first TDD frame structure.

32. The first message is a message in which the terminal reports its location measurement result for the first time after completing the initial random access. The TDD frame structure arrangement information carried in the first system message broadcast by the base station is arrangement information corresponding to the first TDD frame structure. If, after the first message out of all messages sent by the terminal before it sent the first message has been received by the base station, the terminal is not yet assigned to the first terminal set or the second terminal set, then it is determined that the terminal belongs to the first terminal set. The method according to 31, characterized in that the reporting time of the message for reporting the location measurement result for the terminal for the first time is after the terminal has completed initial random access, and after the non-access layer (NAS) has completed individual identification, rights verification and encryption with the core network, and after the control process of the security mode with the base station has been completed through air interface interaction.

33. The first message is the first message that the terminal sends to the base station when it initiates initial random access. When the location measurement result corresponding to the terminal is reported for the first time, the system message is transmitted to the base station along with the first message using pre-allocated time-frequency resources in the system message. The method according to 31, characterized in that the TDD frame structure arrangement information carried in the first system message broadcast by the base station is arrangement information corresponding to the first TDD frame structure, and the terminal transmits the first message using the sequence of the first TDD frame structure.

34. The first message is the first message that the terminal sends to the base station when it initiates initial random access. In the method for determining whether or not to send the first message, and for determining the corresponding frame structure when the first message is sent, Based on the first system message broadcast by the base station, the second system message, the terminal's own position measurement result, and the first planned distance threshold, the terminal now initiates initial random access and determines whether or not to cause inter-terminal shared channel crosslink interference with terminals already assigned to the adjacent second set of terminals. If, as a result of the determination, it is determined that no inter-terminal interference will occur with respect to adjacent terminals in the second set of terminals, the terminal transmits the first message using the sequence of the first TDD frame structure. If, as a result of the determination, it is determined that inter-terminal interference will occur with respect to at least one adjacent terminal in the second set of terminals, the terminal will temporarily refrain from sending the first message. When the first message is scheduled to be sent, and the terminal reports a location measurement result for the first time, the system message includes the step of transmitting the first message along with the location measurement result to the base station using pre-configured time-frequency resources in the system message. The TDD frame structure arrangement information carried in the first system message broadcast by the base station is arrangement information corresponding to the first TDD frame structure. The method according to 31, characterized in that the second system message broadcast by the base station carries location information of terminals already assigned to a second set of terminals at the current wave position covered by the beam carrying the second system message, and location information of terminals already assigned to the second set of terminals at each adjacent wave position where the shortest distance to the boundary of the current wave position is less than or equal to a first predetermined distance threshold.

35. The first message is the first message that the terminal sends to the base station when it initiates initial random access. In the method for determining whether or not to send the first message, and for determining the corresponding frame structure when the first message is sent, The terminal, based on the first system message broadcast by the base station, the second system message, the terminal's own position measurement result, and the first planned distance threshold, now determines whether initiating initial random access will cause inter-terminal shared channel crosslink interference to terminals already assigned to adjacent first or second terminal sets. If, as a result of the determination, it is determined that no inter-terminal interference will occur with respect to any adjacent terminals in the first terminal set or the second terminal set, the terminal transmits the first message using a sequence of the first TDD frame structure or the second TDD frame structure. If the determination is made that inter-terminal interference will occur with neighboring terminals in the first terminal set, but not with neighboring terminals in the second terminal set, the terminal transmits the first message using the sequence of the first TDD frame structure. If the determination is made that inter-terminal interference will occur with respect to adjacent terminals in the second set of terminals, but not with respect to adjacent terminals in the first set of terminals, the terminal transmits the first message using a sequence of the second TDD frame structure. If, as a result of the determination, it is determined that inter-terminal interference will occur between at least one adjacent terminal in the first terminal set and at least one adjacent terminal in the second terminal set, the terminal will temporarily refrain from sending the first message. When the first message is scheduled to be sent, and the terminal reports a location measurement result for the first time, the system message includes the step of transmitting the first message along with the location measurement result to the base station using pre-configured time-frequency resources in the system message. The TDD frame structure arrangement information carried in the first system message broadcast by the base station includes arrangement information corresponding to the first TDD frame structure and arrangement information for the frame header offset required to generate the second TDD frame structure. The second system message broadcast by the base station carries the location information of terminals already assigned to the first and second terminal sets at the current wave position covered by the beam carrying the second system message, and the location information of terminals already assigned to the first and second terminal sets where the shortest distance to the boundary of the current wave position at each adjacent wave position is less than or equal to the first planned distance threshold. The method according to feature 31.

36. The method according to 31, further comprising the step of performing interference rejection on the inter-terminal shared channel subband crosslink interference that remains on the terminal side despite subband-level frequency division scheduling, using one or more of the following methods: spatial domain interference rejection, analog domain interference rejection, and digital domain interference rejection, when, after avoiding possible inter-terminal shared channel crosslink interference between terminals using a subband-level frequency division scheduling scheme between terminals using several different frame structures, shared channel crosslink interference has indeed occurred between those terminals.

37. A satellite communication device based on a time-division duplex TDD frame structure design, which is applied to network equipment, and the device is A specific module arranged to identify a predetermined group of time-division duplex TDD frame structures corresponding to a base station, wherein the predetermined group of TDD frame structures includes a first TDD frame structure and a second TDD frame structure generated by offsetting the frame header relative to the first TDD frame structure, A decision module configured to determine the set of terminals to which a terminal belongs in response to receiving a first message transmitted from a terminal, wherein the set of terminals is a decision module that is a first set of terminals or a second set of terminals, If the terminal belongs to the first terminal set, a first scheduling module is configured to perform scheduling for the terminal based on the first TDD frame structure, If the terminal belongs to the second set of terminals, a second scheduling module is provided which is configured to perform scheduling for the terminal based on the second TDD frame structure, A satellite communication device based on a time-division duplex TDD frame structure design, characterized by having the following features.

38. A satellite communication device based on a time-division duplex TDD frame structure design, applied to a user terminal (UE), wherein the device is A transmission module positioned to send a first message corresponding to the terminal to the base station, The module includes a scheduling reception module used in the module and configured to receive scheduling from the base station to the terminal based on a first TDD frame structure or a second TDD frame structure, The second TDD frame structure is generated by offsetting the frame header relative to the first TDD frame structure. A satellite communication device based on a time-division duplex TDD frame structure design, characterized by the following features.

39. At least one processor, The system comprises a memory connected to at least one of the processors, The memory stores commands that can be executed by the at least one processor. A communication device characterized in that, by executing the command by the at least one processor, the at least one processor is able to perform the method according to any one of claims 1 to 30 or 31 to 36.

40. The computer has a list of executable commands stored in it. A computer storage medium characterized in that, when a command executable by the computer is executed by a processor, the method described in any one of claims 1 to 30 or 31 to 36 is realized.

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