A satellite communication method and device based on a time division duplex (TDD) frame structure design

Abstract

The application provides a satellite communication method and device based on a time division duplex (TDD) frame structure design, and relates to the technical field of wireless communication. The method comprises the following steps: determining a preset TDD frame structure group corresponding to a base station, wherein the preset TDD frame structure group comprises a first TDD frame structure and a second TDD frame structure generated by performing frame header offset on the first TDD frame structure; in response to receiving a first message sent by a terminal, judging a terminal set to which the terminal belongs, wherein the terminal set is a first terminal set or a second terminal set; if the terminal belongs to the first terminal set, scheduling the terminal based on the first TDD frame structure; and if the terminal belongs to the second terminal set, scheduling the terminal based on the second TDD frame structure. According to the application, the spaceborne base station can communicate with another part of UE in the period of waiting (i.e. in the period of the GP of the corresponding frame structure) between a part of UE and the spaceborne base station, so that the air interface resource utilization rate of the whole system is improved.

Description

Technical Field

[0001] This invention relates to the field of wireless communication, and in particular to a satellite communication method and apparatus based on a time-division duplex (TDD) frame structure design. Background Technology

[0002] Currently, for Low Earth Orbit (LEO) satellite systems, whether in existing operational systems or in the 3GPP international standard for 5G Non-Terrestrial Networks (NTN), the satellite-to-ground user link is considered to adopt the FDD (Frequency Division Duplex) standard. However, considering the scarcity of available spectrum resources for FDD systems (especially in the spectrum range below 6 GHz), and the low spectrum utilization caused by asymmetric uplink and downlink services, which are the mainstream service types, in FDD systems, the industry is actively exploring the application of the TDD (Time Division Duplex) standard to the satellite-to-ground user link.

[0003] In related technologies, to fully utilize the time-domain resources under the TDD standard, different satellite-based base stations projecting onto different cells on the ground can cross-use the GP (Guard Period) time slots between different cells for data transmission and reception. However, this scheme has the following problems: it does not sufficiently improve resource utilization. During the duration of each GP time slot belonging to a certain cell, only one satellite-based base station in the entire system can communicate with some user terminals (i.e., User Equipment, UEs), which does not achieve the more ideal situation described below: during the duration of each GP time slot belonging to a certain cell, each satellite-based base station in the system can communicate with some UEs. Summary of the Invention

[0004] This application proposes a satellite communication method and apparatus based on a time-division duplex (TDD) frame structure design, which enables a satellite-borne base station to communicate with another group of UEs during the waiting period when communication with a group of UEs is in progress (i.e., during the GP period of the corresponding frame structure), thereby improving the air interface resource utilization of the entire system.

[0005] The first aspect of this application proposes a satellite communication method based on a time-division duplex (TDD) frame structure design, applied to network equipment, comprising: determining a preset TDD frame structure group corresponding to a base station, wherein the preset TDD frame structure group includes a first TDD frame structure and a second TDD frame structure generated by offsetting the frame header of the first TDD frame structure; responding to receiving a first message sent by a terminal, determining the terminal set to which the terminal belongs, wherein the terminal set is a first terminal set or a second terminal set; if the terminal belongs to the first terminal set, scheduling the terminal based on the first TDD frame structure; if the terminal belongs to the second terminal set, scheduling the terminal based on the second TDD frame structure.

[0006] In this embodiment of the application, within a cell, based on the classification and scheduling of UEs by the satellite base station, a portion of the ground UEs adopt the first TDD frame structure, while the TDD frame structure of another portion of the ground UEs adopts the frame header offset version of the first TDD frame structure, i.e., the second TDD frame structure. Furthermore, all (or part) of the DL and UL time slots in the second TDD frame structure correspond to the GP time slots of the first TDD frame structure (i.e., they occur at the same time). At the same time, this naturally also causes all (or part) of the DL and UL time slots in the first TDD frame structure to correspond to the GP time slots of the second TDD frame structure. This allows the satellite base station to communicate with the other portion of UEs during the waiting period of communication with a portion of the UEs (i.e., during the GP time period of the corresponding frame structure), thereby improving the air interface resource utilization of the entire system.

[0007] The second aspect of this application proposes a satellite communication method based on a time-division duplex (TDD) frame structure design, applied to a user terminal (UE), comprising: sending a first message corresponding to the terminal to a base station; and receiving scheduling of the terminal by the base station 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 of the first TDD frame structure.

[0008] A third aspect of this application proposes a satellite communication device based on a Time Division Duplex (TDD) frame structure design, applicable to network equipment. The device includes: a determining module configured to determine a preset TDD frame structure group corresponding to a base station, wherein the preset TDD frame structure group includes a first TDD frame structure and a second TDD frame structure generated by offsetting the frame header of the first TDD frame structure; a judging module configured to, in response to receiving a first message sent by a terminal, judge the terminal set to which the terminal belongs, wherein the terminal set is a first terminal set or a second terminal set; a first scheduling module configured to, if the terminal belongs to the first terminal set, schedule the terminal based on the first TDD frame structure; and a second scheduling module configured to, if the terminal belongs to the second terminal set, schedule the terminal based on the second TDD frame structure.

[0009] The fourth aspect of this application proposes a satellite communication device based on a time-division duplex (TDD) frame structure design, characterized in that it is applicable to a user terminal (UE). The device includes: a transmitting module configured to transmit a first message corresponding to the terminal to a base station; and a receiving and scheduling module configured to receive scheduling of the terminal by the base station 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 of the first TDD frame structure.

[0010] A fifth aspect of this application provides a communication device, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to execute the satellite communication method based on the time-division duplex (TDD) frame structure design described in the first aspect of this application, or the satellite communication method based on the time-division duplex (TDD) frame structure design described in the second aspect of this application.

[0011] A sixth aspect of this application provides a computer storage medium storing computer-executable instructions. When executed by a processor, the computer-executable instructions can implement the satellite communication method based on the time-division duplex (TDD) frame structure design described in the first aspect of this application, or the satellite communication method based on the time-division duplex (TDD) frame structure design described in the second aspect of this application. Attached Figure Description

[0012] Figure 1 A schematic diagram illustrating an exemplary implementation of a satellite communication method based on a time-division duplex (TDD) frame structure design provided in this application.

[0013] Figure 2(a) is a schematic diagram of a first TDD frame structure in which the sum of the number of DL time slots and UL time slots is equal to the number of GP time slots N, as shown in this application;

[0014] Figure 2(b) is a schematic diagram of the frame structure timing on the base station side generated by offsetting the frame header of the first TDD frame structure by N time slots, as shown in this application.

[0015] Figure 3(a) is a schematic diagram of a first TDD frame structure in which the sum of the number of DL time slots and UL time slots is less than the number of GP time slots N, as shown in this application.

[0016] Figure 3(b) is a timing diagram of the frame structure generated on the base station side by offsetting the frame header of the first TDD frame structure according to this application;

[0017] Figure 4(a) is a schematic diagram of a first TDD frame structure in which the sum of the number of DL time slots and UL time slots is greater than the number of GP time slots N, as shown in this application.

[0018] Figure 4(b) is a timing diagram of a frame structure generated on the base station side by offsetting the frame header of the first TDD frame structure according to this application.

[0019] Figure 5 This application illustrates a schematic diagram of frequency division multiplexing at the subband level using subband full-duplex technology.

[0020] Figure 6 This application illustrates a schematic diagram of a method for generating cross-link interference between UEs in a common channel.

[0021] Figure 7 This is a schematic diagram of an exemplary implementation of a satellite communication method based on a time-division duplex (TDD) frame structure design as shown in this application;

[0022] Figure 8 This application illustrates a schematic diagram of a method for generating cross-link interference between UEs in a common channel.

[0023] Figure 9 This is a schematic diagram of an exemplary implementation of a satellite communication method based on a time-division duplex (TDD) frame structure design as shown in this application;

[0024] Figure 10 This is a schematic diagram of an exemplary implementation of a satellite communication method based on a time-division duplex (TDD) frame structure design as shown in this application;

[0025] Figure 11 This application illustrates a schematic diagram of dividing the coverage area of ​​a base station into an outer ring and an inner ring;

[0026] Figure 12This is a schematic diagram of determining the CD-SSB transmission slots using the first frame structure group design scheme as an example;

[0027] Figure 13 This is a schematic diagram of an exemplary implementation of a satellite communication method based on a time-division duplex (TDD) frame structure design as shown in this application;

[0028] Figure 14 This is a schematic diagram of the structure of a satellite communication device based on a time-division duplex (TDD) frame structure proposed in an embodiment of this application;

[0029] Figure 15 This is a schematic diagram of another satellite communication device based on a time-division duplex (TDD) frame structure proposed in this application embodiment;

[0030] Figure 16 This is a schematic diagram of a communication device provided in an embodiment of this application. Detailed Implementation

[0031] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements, or elements having the same or similar functions, throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0032] In related technologies, for a TDD system to function properly, the GP (Guard Period) required for the conversion between DL (Downlink) and UL (Uplink) time slots in the frame format must be greater than or equal to the round-trip time (RTT) of signal propagation between the base station and the far end of the cell. radius When TDD is applied to the satellite-to-ground user link of a low-Earth orbit satellite, given the long signal propagation distance between the satellite and the ground user equipment (UE), RTT... radius The magnitude of the GP will be relatively large, resulting in a long duration of GP; and a long GP will lead to a relatively low utilization rate of air interface resources in the entire system.

[0033] For example: for a certain low-Earth orbit satellite system, RTT radius The order of magnitude is 5 milliseconds (ms). Typically, GP can be set equal to RTT. radiusTherefore, GP equals 5ms. If the subcarrier spacing is 30kHz (i.e., the duration of each time slot is 0.5ms), then 10 special time slots, all of which are GP, are needed between the DL time slot and the UL time slot (hereafter, we will refer to the special time slots, all of which are GP, as "GP time slots").

[0034] In some schemes, to fully utilize the time-domain resources under the TDD standard, different cells projected from different satellite base stations onto the ground can cross-use the GP (Guarantee Period) time slots between different cells for data transmission and reception. However, this scheme has the following problems:

[0035] 1. This scheme does not improve resource utilization enough. During the duration of each GP time slot belonging to a certain cell, only one satellite base station in the entire system can communicate with some user terminals (i.e., User Equipment, abbreviated as UE). It has not yet achieved the more ideal situation described below: during the duration of each GP time slot belonging to a certain cell, each satellite base station in the system can communicate with some UEs.

[0036] 2. More importantly, when using this scheme, there is a possibility that a UE located at the edge of a cell and an edge UE in a neighboring cell may be in a situation where one is receiving downlink data while the other is transmitting uplink data. If these two edge UEs located in different cells are close to each other, "inter-UE co-channel cross-link interference" will occur. If this interference cannot be effectively avoided, the scheme is actually not feasible.

[0037] 3. In addition, when using this scheme, because the starting positions of the system frames of different cells need to be shifted and staggered, the requirements for time synchronization between adjacent satellites are very stringent.

[0038] 4. Furthermore, no general, standard design guidelines are given for the ratio between the number of DL time slots, UL time slots, and GP time slots; only an example is provided.

[0039] To address the aforementioned technical problems, this application provides a satellite communication method and apparatus based on a time-division duplex (TDD) frame structure design.

[0040] Figure 1 This is a schematic diagram illustrating an exemplary implementation of a satellite communication method based on a Time Division Duplex (TDD) frame structure design, applicable to network devices, such as... Figure 1 As shown, this satellite communication method based on the Time Division Duplex (TDD) frame structure includes the following steps:

[0041] S101, determine the preset time division duplex (TDD) frame structure group corresponding to the base station, wherein the preset TDD frame structure group includes a first TDD frame structure and a second TDD frame structure generated after offsetting the frame header of the first TDD frame structure.

[0042] This application lists the following three design methods for preset TDD frame structure groups for selection.

[0043] The first feasible frame structure design method, which pre-defines the acquisition method of the TDD frame structure group, includes: setting a first TDD frame structure, wherein the number of guard interval (GP) time slots in the first TDD frame structure is N (N is a positive integer), and the sum of the number of downlink DL time slots and uplink UL time slots in the first TDD frame structure is equal to N. Figure 2(a) is a schematic diagram of a first TDD frame structure in which the sum of the number of DL time slots and UL time slots is equal to the number of GP time slots N. Based on Figure 2(a), the frame header of the first TDD frame structure is offset by N time slots to obtain a second TDD frame. The structure, wherein, Figure 2(b) is a schematic diagram of the frame structure timing on the base station side generated by offsetting the frame header of the first TDD frame structure 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 of the first TDD frame structure. The satellite base station can use the first TDD frame structure and the second TDD frame structure to schedule a portion of UEs at the same time. After determining the first TDD frame structure and the second TDD frame structure, a preset TDD frame structure group is generated based on the first TDD frame structure and the second TDD frame structure.

[0044] In the first frame structure design implementation, the satellite base station can always communicate with some UEs, and there is no period of "having to wait".

[0045] In the first frame structure design implementation, the network side will not experience uplink or downlink conflicts in any time slot, nor will it introduce any new interference.

[0046] The second feasible frame structure design method includes a preset method for obtaining TDD frame structure groups, comprising: setting a first TDD frame structure, wherein the number of GP slots in the first TDD frame structure is N, and the sum of the number of DL slots and UL slots in the first TDD frame structure is less than N. Figure 3(a) is a schematic diagram of a first TDD frame structure in which the sum of the number of DL slots and UL slots is less than the number of GP slots N, as shown in this application. Based on Figure 3(a), the first TDD frame structure is offset by a frame header to obtain a second TDD frame structure. b) is a schematic diagram of the frame structure timing of the base station side generated by offsetting the frame header of the first TDD frame structure according to 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 of the first TDD frame structure. The satellite base station can use the first TDD frame structure and the second TDD frame structure to schedule a portion of UEs at the same time. After determining the first TDD frame structure and the second TDD frame structure, a preset TDD frame structure group is generated based on the first TDD frame structure and the second TDD frame structure.

[0047] In the second frame structure design implementation, the satellite base station cannot always communicate with some UEs. In other words, there are still periods of "waiting". In the example in Figure 3(b), two consecutive time slots are still wasted.

[0048] In the second frame structure design implementation, the network side will not experience uplink or downlink conflicts in any time slot, nor will it introduce any new interference.

[0049] The third feasible frame structure design method includes a preset method for obtaining TDD frame structure groups, comprising: setting a first TDD frame structure, wherein the number of GP slots in the first TDD frame structure is N, and the sum of the number of DL slots and UL slots in the first TDD frame structure is greater than N. Figure 4(a) is a schematic diagram of a first TDD frame structure in which the sum of the number of DL slots and UL slots is greater than the number of GP slots N. Based on Figure 4(a), the first TDD frame structure is offset by a frame header to obtain a second TDD frame structure. Figure 4(b) is a schematic diagram of a first TDD frame structure in which the sum of the number of DL slots and UL slots is greater than the number of GP slots N. The request provides a schematic diagram of the frame structure timing generated by offsetting the frame header of the first TDD frame structure to the base station side, as shown in Figure 4(b). Some of the time slots in 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. There are conflicting time slots between the first TDD frame structure and the second TDD frame structure. The satellite base station can use the first TDD frame structure and the second TDD frame structure to schedule a portion of UEs at the same time. A preset TDD frame structure group is generated based on the first TDD frame structure and the second TDD frame structure.

[0050] In the third frame structure design implementation, taking the example in Figure 4(b) as an example, in each frame period of the second TDD frame structure, there are 2 DL time slots that conflict with the 2 UL time slots in each frame period of the first TDD frame structure in the uplink and downlink directions. These two time slots are referred to as conflict time slots.

[0051] In the third frame structure design implementation, the satellite base station can always communicate with some UEs, that is, there is no period of "having to wait".

[0052] S102, in response to receiving the first message sent by the terminal, determine the terminal set to which the terminal belongs, wherein the terminal set is either the first terminal set or the second terminal set.

[0053] The first terminal set is a set of terminals that are invoked to use the first TDD frame structure.

[0054] The second terminal set is a set of terminals that are invoked to use the second TDD frame structure.

[0055] Optionally, the first message is the message in which the terminal reports the location measurement results corresponding to the terminal for the first time after completing the initial random access.

[0056] Optionally, the first message is the first message sent by the terminal to the base station when initiating initial random access.

[0057] If the base station receives the first message sent by the terminal, it determines the terminal set to which the terminal belongs based on a preset terminal set determination criterion. The terminal set determination criterion includes, but is not limited to, the terminal number balance criterion or the dice-rolling random criterion.

[0058] S103, if the terminal belongs to the first terminal set, schedule the terminal based on the first TDD frame structure.

[0059] S104, if the terminal belongs to the second terminal set, schedule the terminal based on the second TDD frame structure.

[0060] In this embodiment of the application, within a cell, based on the classification and scheduling of UEs by the satellite base station, a portion of the ground UEs adopt the first TDD frame structure, while the TDD frame structure of another portion of the ground UEs adopts the frame header offset version of the first TDD frame structure, i.e., the second TDD frame structure. Furthermore, all (or part) of the DL and UL time slots in the second TDD frame structure correspond to the GP time slots of the first TDD frame structure (i.e., they occur at the same time). At the same time, this naturally also causes all (or part) of the DL and UL time slots in the first TDD frame structure to correspond to the GP time slots of the second TDD frame structure. This allows the satellite base station to communicate with the other portion of UEs during the waiting period of communication with a portion of the UEs (i.e., during the GP time period of the corresponding frame structure), thereby improving the air interface resource utilization of the entire system.

[0061] Based on the above embodiments, if the preset TDD frame structure group adopts the third frame structure design in actual use, in order to avoid interference introduced from the network side, we can use the following two methods:

[0062] 1. The first feasible way to avoid interference introduced by the network side is to set the conflicting time slots on the first TDD frame structure to silent; or, set the conflicting time slots on the second TDD frame structure to silent.

[0063] Based on this silent processing, no additional interference is introduced on the network side; and, as expected, the base station will not have any "must-wait" periods. Of course, some UEs will lose a small number of communication opportunities in the downlink (or uplink) direction, so although the overall air interface resource utilization of the system will be improved, it will not be optimal. Taking the specific frame structure in Figure 4(b) as an example, a specific processing method can be: setting the two DL time slots (conflicting time slots) in each frame period of the second TDD frame structure to silent (i.e., not performing DL scheduling for any UE that is currently using the second TDD frame structure in these two time slots); because the UEs scheduled to use the second TDD frame structure will sacrifice a small number of DL reception opportunities in each frame period, during scheduling, based on the amount of downlink data of different users, UEs with relatively smaller downlink data requirements can be given priority to use the second TDD frame structure.

[0064] 2. A second feasible method to avoid network-side interference: To avoid network-side interference, during base station scheduling, for conflicting time slots, sub-band full-duplex technology can be used for frequency division multiplexing at the sub-band level 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. (Note: According to the Rel-18 definition, "sub-band full-duplex" is only a duplex operation enhancement performed on the base station side; the terminal side maintains half-duplex operation.) Figure 5 This application illustrates a schematic diagram of frequency division multiplexing at the sub-band granularity using sub-band full-duplex technology.

[0065] Taking the specific frame structure in Figure 4(b) as an example, for every two conflicting time slots, during scheduling, the satellite base station uses sub-band full-duplex technology to perform frequency division multiplexing at the sub-band level for receiving uplink data from terminals scheduled by the base station to use the first TDD frame structure and sending downlink data from terminals scheduled by the base station to use the second TDD frame structure.

[0066] After frequency division multiplexing at the subband level using subband full-duplex technology for receiving uplink data from terminals scheduled by the base station to use one of the first and second TDD frame structures, and transmitting downlink data from terminals scheduled by the base station to use the other of the first and second TDD frame structures, the residual inter-subband interference at the base station side includes "gNB's self-interference" and "gNB-to-gNB co-channel inter-subband cross-link interference". For both types of interference, the interference avoidance scheme discussed in Rel-18 for "subband full-duplex" is adopted to achieve good interference avoidance. Specific interference avoidance schemes can be one or more of the following: interference cancellation schemes in the spatial domain (e.g., increasing the separation of transmit and receive antennas and antenna isolation design), interference cancellation schemes in the analog domain (e.g., increasing analog high rectangular coefficient filters to improve filtering performance), and interference cancellation schemes in the digital domain (e.g., signal processing for interference cancellation using transmitter information). These schemes aim to eliminate two types of inter-subband interference remaining on the network side, including base station self-interference and cross-link interference between common sub-bands of base stations.

[0067] Regardless of which of the three feasible frame structure designs mentioned above is adopted, there will be no inter-UE interference between any two UEs in the UE set using the same frame structure. Below, we will provide a more detailed analysis of the potential "UE-to-UE co-channel cross-link interference" between UEs using the first TDD frame structure and UEs using the second TDD frame structure.

[0068] 1. When using the first frame structure design method, the second frame structure design method, and the third frame structure design method with a silent handling scheme for uplink and downlink conflicts occurring on some time slots on the network side: In a terrestrial network, there will be no inter-UE co-channel cross-link interference between UEs using the first TDD frame structure and UEs using the second TDD frame structure within the cell. However, Figure 6 This application illustrates a schematic diagram of cross-link interference between UEs in a shared channel, as shown below. Figure 6 As shown, due to the excessively large propagation distance on the satellite-to-ground link, it is possible that a UE in the set of UEs using the first TDD frame structure (i.e., the first terminal set) and a UE in the set of UEs using the second TDD frame structure (i.e., the second terminal set) may be in a situation where one is receiving downlink data while the other is transmitting uplink data. If the two UEs are relatively close at this time, cross-link interference between UEs in the same channel will occur.

[0069] 2. When using the third frame structure design method and employing the second feasible subband full-duplex processing scheme to avoid network-side interference in situations where uplink and downlink conflicts occur on some time slots:

[0070] Whether in terrestrial networks or LEO satellite networks, UEs using the first TDD frame structure and UEs using the second TDD frame structure will experience cross-link interference in the same channel. In this case, uplink and downlink conflicts will occur on the network side in a small number of time slots. We have proposed using sub-band full-duplex to resolve these conflicts.

[0071] For the inter-UE co-channel cross-link interference that may occur between "a UE in the set of UEs using the first TDD frame structure (i.e., the first terminal set)" and "a UE in the set of UEs using the second TDD frame structure (i.e., the second terminal set)", we will design interference avoidance strategies for two categories: the inter-UE co-channel cross-link interference that may exist between "UEs that have initiated initial random access" and "UEs that have initiated initial random access".

[0072] Figure 7 This is a schematic diagram illustrating an exemplary implementation of a satellite communication method based on a Time Division Duplex (TDD) frame structure design, as shown in this application. This embodiment mainly introduces a method for avoiding co-channel cross-link interference that may exist between UEs "after initiating initial random access" using a sub-band level frequency division scheduling scheme. Figure 7 As shown, this satellite communication method based on the Time Division Duplex (TDD) frame structure includes the following steps:

[0073] S701, determine the preset time division duplex (TDD) frame structure group corresponding to the base station, wherein the preset TDD frame structure group includes a first TDD frame structure and a second TDD frame structure generated after offsetting the frame header of the first TDD frame structure.

[0074] S702, in response to receiving the first message sent by the terminal, determines the terminal set to which the terminal belongs, wherein the terminal set is either the first terminal set or the second terminal set.

[0075] S703, if the terminal belongs to the first terminal set, the terminal is scheduled based on the first TDD frame structure.

[0076] S704, if the terminal belongs to the second terminal set, the terminal is scheduled based on the second TDD frame structure.

[0077] For details on the specific implementation of steps S701 to S704, please refer to the specific description of the relevant parts of steps S101 to S104 in the above embodiments, which will not be repeated here.

[0078] S705 When there is inter-terminal cross-link interference between any first terminal belonging to the first terminal set and any second terminal belonging to the second terminal set, a sub-band level frequency division scheduling scheme is adopted to avoid interference.

[0079] The following section will introduce two scenarios for using sub-band level frequency division scheduling schemes to avoid interference.

[0080] 1. When using the first frame structure design method, the second frame structure design method, or the third frame structure design method, and when a silent handling scheme is adopted for situations where uplink and downlink conflicts occur on the network side in some time slots:

[0081] There are no uplink or downlink conflicts on the network side. Therefore, although subband-level frequency division scheduling is performed, at the base station, the transmit and receive operation at any given time is not equivalent to "subband full-duplex". Moreover, there is no "base station self-interference" or "inter-base station co-channel subband cross-link interference" on the base station side.

[0082] Meanwhile, it's easy to understand that on the UE side, after sub-band frequency division isolation, if there is residual "UE-to-UE co-channel inter-subband cross-link interference," the specific interference avoidance scheme will adopt the effective interference avoidance schemes discussed in Rel-18 for "sub-band full-duplex." These schemes can be one or more of the following: spatial interference cancellation schemes (e.g., increasing transmit / receive antenna separation and antenna isolation design), analog interference cancellation schemes (e.g., adding analog high rectangular coefficient filters to improve filtering performance), and digital interference cancellation schemes (e.g., signal processing for interference cancellation using transmitter information). Figure 8 This application illustrates a schematic diagram of a method for generating cross-link interference between UEs in a common channel.

[0083] 2. When using the third frame structure design and employing a sub-band full-duplex processing scheme to address uplink / downlink conflicts that occur on some time slots on the network side:

[0084] At this point, for the conflicting time slots where uplink and downlink conflicts occur on the network side, since "sub-band full-duplex" is already used, sub-band-level frequency division scheduling has already been achieved. For other time slots, sub-band-level frequency division scheduling can be performed separately (Note: At the base station, the transmit and receive operations at any time in these other time slots are not equivalent to "sub-band full-duplex").

[0085] At the same time, it is easy to understand that, similar to the above, on the UE side, after sub-band frequency division isolation, if there is residual "UE-to-UE co-channel inter-subband cross-link interference," the specific interference avoidance scheme will adopt the effective interference avoidance schemes discussed in Rel-18 for "sub-band full-duplex." These schemes can be one or more of the following: spatial interference cancellation schemes (e.g., increasing transmit / receive antenna separation and antenna isolation design), analog interference cancellation schemes (e.g., adding analog high rectangular coefficient filters to improve filtering performance), and digital interference cancellation schemes (e.g., signal processing for interference cancellation using transmitter information).

[0086] Figure 9 This is a schematic diagram illustrating an exemplary implementation of a satellite communication method based on a Time Division Duplex (TDD) frame structure design, as shown in this application. This embodiment mainly introduces a method for avoiding potential co-channel cross-link interference between UEs "after initiating initial random access" based on geographical isolation. Figure 9 As shown, this satellite communication method based on the Time Division Duplex (TDD) frame structure includes the following steps:

[0087] S901, determine the preset time division duplex (TDD) frame structure group corresponding to the base station, wherein the preset TDD frame structure group includes a first TDD frame structure and a second TDD frame structure generated after offsetting the frame header of the first TDD frame structure.

[0088] Regarding the specific implementation of step S901, there are three design schemes for the preset TDD frame structure group. Please refer to the specific description of the relevant part in step S101 in the above embodiment, which will not be repeated here.

[0089] S902, in response to receiving a first message sent by a terminal, obtain a first location information set corresponding to each first terminal in the first terminal set, wherein the first terminal is in a connected state with the base station.

[0090] The first terminal set is a set of terminals that are invoked to use the first TDD frame structure.

[0091] Each terminal in the first terminal set is designated as a first terminal. The location information of each first terminal is obtained as first location information, and a first location information set is generated based on all the first location information.

[0092] Optionally, the first terminal may report its own location information along with the traditional measurement report message. The base station will then store at least the most recently reported location information and retrieve it from its memory when needed.

[0093] Optionally, the base station can explicitly and in real-time query the location information of the first terminal through a "terminal information request message".

[0094] Optionally, the first terminal can periodically or in an event-triggered manner (e.g., when it discovers that a change in its location has caused a distance change exceeding a threshold) specifically report its location information. The base station will then store at least the most recently reported location information and retrieve it from its memory when needed.

[0095] S903, obtain the second location information set corresponding to each second terminal in the second terminal set, wherein the second terminal is in a connected state with the base station.

[0096] The second terminal set is a set of terminals that are invoked to use the second TDD frame structure.

[0097] Each terminal in the second terminal set is designated as a second terminal. The location information of each second terminal is obtained as second location information, and a second location information set is generated based on all the second location information.

[0098] S904, obtain the terminal location information corresponding to the terminal.

[0099] Obtain the terminal location information corresponding to the terminal that sent the first message, that is, obtain the terminal location information corresponding to the terminal that the base station needs to determine whether the call is based on the first TDD frame structure or the second TDD frame structure.

[0100] S905: Determine the terminal set to which the terminal belongs based on the first location information set, the second location information set, and the terminal location information.

[0101] In the LEO satellite system, each UE reports its own geographical location information obtained through GNSS (such as my country's BeiDou system) to the onboard base station.

[0102] Each LEO satellite system cell covers a vast area on the ground (on the order of hundreds of thousands or even millions of square kilometers); therefore, there is enough geographical space within each cell to allow the distance between two UEs within the cell to be large enough to effectively avoid mutual interference between UEs.

[0103] It's easy to understand that the base station uses two different frame structures to schedule a portion of the UEs in the cell, which is equivalent to dividing the UEs in the corresponding cell into two user sets.

[0104] Therefore, in order to avoid "inter-UE co-channel cross-link interference" within the cell, we can consider having the base station, during scheduling, try to ensure 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" is greater than a first preset distance threshold.

[0105] Specifically, for any UE that initiates initial random access, when the base station decides whether the UE adopts the first TDD frame structure or the second TDD frame structure, it first obtains the minimum distance between the terminal and each first terminal in the first terminal set as the first distance based on the first location information set and the terminal location information.

[0106] Based on the second location information set and the terminal location information, the minimum distance between the terminal and each second terminal in the second terminal set is obtained as the second distance.

[0107] The first distance, the second distance, and a first preset distance threshold are compared to determine the terminal set to which the terminal belongs. Several possible scenarios are shown below:

[0108] If both the first distance and the second distance are greater than or equal to the first preset distance threshold, the base station can allow the UE to use either the first TDD frame structure or the second TDD frame structure. In other words, geographical isolation alone can be used to avoid interference between UEs. In this way, it can be determined whether the terminal belongs to the first terminal set or the second terminal set.

[0109] If the first distance is greater than or equal to the first preset distance threshold and the second distance is less than the first preset distance threshold, then the terminal is determined to belong to the first terminal set. That is, in this case, interference between UEs can be avoided simply by using geographical isolation.

[0110] If the first distance is less than the first preset distance threshold and the second distance is greater than or equal to the first preset distance threshold, then the terminal is determined to belong to the second terminal set. That is, in this case, interference between UEs can be avoided simply by using geographical isolation.

[0111] If both the first distance and the second distance are less than a first preset distance threshold, meaning that geographical isolation alone is insufficient to avoid interference between UEs, then the terminal set to which the terminal belongs is determined based on a preset terminal set determination criterion. This criterion includes, but is not limited to: determining the terminal set to which the terminal belongs based on a balance criterion between the number of terminals in the first terminal set and the second terminal set; or, determining the terminal set to which the terminal belongs based on a criterion of randomly selecting one of these criteria.

[0112] S906, if the terminal belongs to the first terminal set, the terminal is scheduled based on the first TDD frame structure.

[0113] S907, if the terminal belongs to the second terminal set, the terminal is scheduled based on the second TDD frame structure.

[0114] In this embodiment of the application, within a cell, based on the classification and scheduling of UEs by the satellite base station, a portion of the ground UEs adopt the first TDD frame structure, while the TDD frame structure of another portion of the ground UEs adopts the frame header offset version of the first TDD frame structure, i.e., the second TDD frame structure. Furthermore, all (or part) of the DL and UL time slots in the second TDD frame structure correspond to the GP time slots of the first TDD frame structure (i.e., they occur at the same time). At the same time, this naturally also causes all (or part) of the DL and UL time slots in the first TDD frame structure to correspond to the GP time slots of the second TDD frame structure. This allows the satellite base station to communicate with the other portion of UEs during the waiting period of communication with a portion of the UEs (i.e., during the GP time period of the corresponding frame structure), thereby improving the air interface resource utilization of the entire system.

[0115] Furthermore, if both the first distance and the second distance are less than the first preset distance threshold, after determining the terminal set to which the terminal belongs based on the preset terminal set determination criteria, the process further includes:

[0116] If the terminal belongs to the second terminal set, then based on the first location information set and the terminal location information, a first terminal subset from the first terminal set whose distance value from the terminal is less than a first preset distance threshold is obtained, and a sub-band-level frequency division scheduling scheme is adopted to avoid co-channel cross-link interference between the terminal and each terminal in the first terminal subset; and,

[0117] If the terminal belongs to the first terminal set, then based on the second location information set and the terminal location information, a second terminal subset in the second terminal set whose distance value from the terminal is less than the first preset distance threshold is obtained, and a sub-band-level frequency division scheduling scheme is adopted to avoid co-channel cross-link interference between the terminal and each terminal in the second terminal subset.

[0118] Furthermore, because UEs are mobile, the geographical distance between UEs may change. If 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 that reported the location update information is re-determined based on the location update information and the steps S902 to S905 described above.

[0119] In addition, a further optimization can be considered: based on the changes in the distance between UEs, the base station can switch the frame structure used by a certain UE between the first TDD frame structure and the second TDD frame structure at an appropriate time; thereby trying to avoid interference between UEs by relying solely on geographical isolation.

[0120] When re-determining the terminal set corresponding to the terminal that reported the location update information based on the location update information, the terminal set to which at least one terminal in the first terminal set and the second terminal set belongs that did not report the location update information is modified, so that the number of terminals in the updated first terminal set and the second terminal set that need to use a sub-band level frequency division scheduling scheme to avoid cross-link interference between terminals can be minimized.

[0121] It is important to note that when using the first, second, or third frame structure design methods, and when employing a silent handling scheme for uplink / downlink conflicts occurring on some time slots on the network side, even if two UEs using different frame structures encounter a situation where "one is receiving downlink data while the other is transmitting uplink data," "inter-UE co-channel cross-link interference" will only occur if the two UEs are relatively close to each other. Therefore, when using the first, second, or third frame structure design methods, and when employing a silent handling scheme for uplink / downlink conflicts occurring on some time slots on the network side, the geographical isolation method described in this embodiment can be used to avoid "inter-UE co-channel cross-link interference."

[0122] It is important to note that when using the third frame structure design and employing a subband full-duplex processing scheme to address uplink / downlink conflicts on some time slots, because subband full-duplex processing is already decided upon for a small number of time slots, "inter-UE co-channel subband cross-link interference" will exist between UEs using different frame structures at certain times, regardless of their geographical distance. Therefore, if this specific frame structure design is adopted, the geographical isolation method described in this embodiment is not suitable and is not recommended for avoiding "inter-UE co-channel cross-link interference." Instead, the subband-level frequency division scheduling scheme described in the above embodiment can effectively avoid "inter-UE co-channel cross-link interference."

[0123] The following describes three feasible methods to avoid potential co-channel cross-link interference between UEs that are initiating initial random access and UEs that have already initiated initial random access within a cell.

[0124] The main reason this interference might occur is that for any idle UE, before it initiates initial random access to the satellite base station, the base station typically knows neither its geographical location nor which of the two frame structures it will use to send the first random access message (i.e., Msg1 or MsgA) containing the PRACH preamble sequence (Physical Random Access Channel preamble sequence). Therefore, the cross-link interference between UEs caused by the first random access message of a "UE initiating initial random access" to "UEs after initiating initial random access" requires a specially designed avoidance strategy.

[0125] Option 1:

[0126] If the first message is the message in which the terminal reports its location measurement results for the first time after completing initial random access, then the TDD frame structure configuration information carried by the base station in the first system message broadcast is the configuration information corresponding to the first TDD frame structure. Furthermore, after the base station receives the first message among all messages sent by the terminal before sending the first message, if the terminal is not currently assigned to either the first terminal set or the second terminal set, then the terminal is determined to belong to the first terminal set. The reporting time of the message in which the terminal reports its location measurement results for the first time is after the terminal has completed initial random access and completed identity recognition, authentication, and encryption with the core network through the non-access stratum (NAS), and completed the security mode control process with the base station through air interface interaction.

[0127] If the first message is the first message sent by the terminal to the base station when initiating initial random access, then the first report of the location measurement result corresponding to the terminal is sent to the base station along with the first message using the time and frequency resources pre-configured in the system message; the TDD frame structure configuration information carried by the base station in the first system message broadcast is the configuration information corresponding to the first TDD frame structure, and the terminal uses the timing of the first TDD frame structure to send the first message.

[0128] Regardless of whether the first message is one of the two types mentioned above, in this application, when the base station performs downlink time-frequency resource scheduling for any terminal belonging to the second terminal set, it determines the time slot index of the UL time slot configured to transmit the random access preamble sequence in the first TDD frame structure; obtains the time slot index of multiple consecutive DL time slots in the second TDD frame structure that are within a preset time slot range from the UL time slot configured to transmit the random access preamble sequence in the first TDD frame structure; and when performing frequency domain resource scheduling for each DL time slot in the multiple consecutive DL time slots within the preset time slot range in the second TDD frame structure, it implements sub-band-level frequency division scheduling with the air interface resources configured for initial random access for terminals in the first terminal set. Specifically, each idle-state UE selects to use the timing of the first TDD frame structure to initiate initial random access (i.e., uses the timing of the first TDD frame structure to transmit Msg1 for four-step random access or MsgA for two-step random access). Meanwhile, when the base station performs DL scheduling for UE(s) within the "UE set using the second TDD frame structure", for consecutive DL time slots in the second TDD frame structure that are closest to the "UL time slot in the first TDD frame structure that will transmit the random access preamble sequence", it will avoid the frequency domain resources corresponding to the PRACH occasion in the frequency domain with sub-band as the smallest granularity. If an idle UE does initiate initial random access, and there are "UE(s) using the second TDD frame structure" simultaneously performing DL reception at a distance less than the geographical isolation threshold from that UE, the inter-sub-band interference remaining at these "UE(s) using the second TDD frame structure" will be countered by an organic combination of interference cancellation schemes in the spatial / analog / digital domains discussed in Rel-18.

[0129] Theoretically, even if every idle-state UE chooses to initiate initial random access using the timing of the first TDD frame structure, connected-state UEs are not necessarily required to use the timing of the first TDD frame structure to initiate initial random access (note: there are also situations in connected states where initial random access is required, such as handover). A more reasonable approach is to use the timing of the currently used frame structure to initiate initial random access (which could mean using the timing of the second TDD frame structure). Therefore, the PRACH occasion configuration still needs to be broadcast on the second TDD frame structure. While theoretically, the PRACH occasion broadcast on the first and second TDD frame structures can be set to different configurations, a simpler and more efficient approach is to set the PRACH occasion broadcast on both structures to be exactly the same. Therefore, based on the assumption that "the configuration is exactly the same", in the above description, when referring to PRACH occasion, we did not distinguish between PRACH occasion configured for "UE set using the first TDD frame structure" and PRACH occasion configured for "UE set using the second TDD frame structure".

[0130] Because many PRACH formats have a PRACH transmission period of 1 frame (i.e., each radio frame will have a PRACH occasion during the UL time slot), for the above-mentioned "for the consecutive DL time slots in the second TDD frame structure that are closest to the "UL time slot in the first TDD frame structure that will transmit the random access preamble sequence", the frequency domain resources corresponding to the PRACH occasion will be avoided in the frequency domain with sub-band as the smallest granularity", which is equivalent to performing sub-band level frequency domain isolation between each group of consecutive DL time slots in the first TDD frame structure and the PRACH occasion.

[0131] In this scheme, terminals that are in an idle state and have not yet initiated initial random access to the base station belong to neither the first terminal set nor the second terminal set.

[0132] The second option:

[0133] In this application, if the first message is the first message sent by the terminal to the base station when initiating initial random access, the first report of the location measurement result corresponding to the terminal is sent to the base station along with the first message using the time and frequency resources pre-configured in the system message; the TDD frame structure configuration information carried by the base station in the first system message broadcast is the configuration information corresponding to the first TDD frame structure.

[0134] At this point, as an feasible approach, methods for determining whether the first message is sent and the frame structure corresponding to the first message during transmission include:

[0135] The TDD frame structure configuration information carried by the base station in the first system message broadcast is the configuration information corresponding to the first TDD frame structure;

[0136] The second system message broadcast by the base station carries the location information of terminals that have been assigned to the second terminal set in the current position covered by the beam carrying the second system message, and the location information of terminals that have been assigned to the second terminal set in each adjacent position whose nearest distance from the boundary of the current position is less than or equal to a first preset distance threshold.

[0137] Among them, the first system message and the second system message are used by the terminal to determine whether the current initiation of initial random access will cause inter-terminal co-channel cross-link interference to the neighboring terminals that have been assigned to the second terminal set based on the first system message broadcast by the base station, the second system message, the terminal's own location measurement results, and the first preset distance threshold.

[0138] If the determination result is that there will be no inter-terminal interference to the neighboring terminals in the second terminal set, then the terminal uses the timing of the first TDD frame structure to send the first message.

[0139] If the determination result is that it will cause inter-terminal interference to at least one neighboring terminal in the second terminal set, then the terminal will temporarily not send the first message.

[0140] If the first message is to be sent, the initial report of the location measurement result corresponding to the terminal is sent to the base station along with the first message using the time and frequency resources pre-configured in the system message.

[0141] At this point, as another possible approach, the methods for determining whether the first message is sent and the frame structure corresponding to the first message when it is sent include:

[0142] The TDD frame structure configuration information carried in the first system message broadcast by the base station includes the configuration information corresponding to the first TDD frame structure and the configuration information of the frame header offset required to generate the second TDD frame structure.

[0143] The second system message broadcast by the base station carries the location information of terminals that have been assigned to the first terminal set and the second terminal set in the current position covered by the beam carrying the second system message, and the location information of terminals that have been assigned to the first and second terminal sets in each adjacent position whose nearest distance from the boundary of the current position is less than or equal to a first preset distance threshold.

[0144] Among them, the first system message and the second system message are used by the terminal to determine whether the current initial random access will cause inter-terminal co-channel cross-link interference to the nearby terminals that have been assigned to the first terminal set or the second terminal set based on the first system message broadcast by the base station, the second system message, the terminal's own location measurement results, and the first preset distance threshold.

[0145] If the determination result is that there will be no inter-terminal interference between the neighboring terminals in the first terminal set and the second terminal set, then the terminal uses the timing of the first TDD frame structure or the second TDD frame structure to send the first message.

[0146] If the determination result is that it causes inter-terminal interference to the neighboring terminals of the first terminal set, but does not cause inter-terminal interference to the neighboring terminals of the second terminal set, then the terminal uses the timing of the first TDD frame structure to send the first message.

[0147] If the determination result is that it causes inter-terminal interference to the neighboring terminals of the second terminal set, but does not cause inter-terminal interference to the neighboring terminals of the first terminal set, then the terminal uses the timing of the second TDD frame structure to send the first message.

[0148] If the determination result is that it will cause inter-terminal interference to at least one neighboring terminal in the first terminal set and at least one neighboring terminal in the second terminal set, then the terminal will temporarily not send the first message.

[0149] If the first message is to be sent, the initial report of the location measurement result corresponding to the terminal is sent to the base station along with the first message using the time and frequency resources pre-configured in the system message.

[0150] In practical implementation, for terminal geographic location information that needs to be broadcast by the base station, compression processing can be performed from different angles and / or in different ways before broadcasting to reduce the amount of data. For example, the number of bytes used to represent the information in each dimension of the three-dimensional geographic coordinate system can be appropriately reduced, or two-dimensional instead of three-dimensional geographic coordinates can be used, or a suitable information compression algorithm can be specifically adopted.

[0151] In this scheme, terminals that are in an idle state and have not yet initiated initial random access to the base station belong to neither the first terminal set nor the second terminal set.

[0152] The third option:

[0153] If the first message is the first report of the location measurement results of the terminal after the initial random access is completed, then the TDD frame structure configuration information carried by the base station in the first system message broadcast is the configuration information corresponding to the first TDD frame structure. Before sending the first message, the terminal sends and receives messages based on the timing defined by the first TDD frame structure.

[0154] If the first message is the first message sent by the terminal to the base station when initiating initial random access, then the first report of the location measurement result corresponding to the terminal is sent to the base station along with the first message using the time and frequency resources pre-configured in the system message; the TDD frame structure configuration information carried by the base station in the first system message broadcast is the configuration information corresponding to the first TDD frame structure.

[0155] Regardless of whether the first message is one of the two types mentioned above, in this application, any historical terminal that has accessed a base station and entered the connected state, after it becomes idle, as long as the base station finds that the terminal is still in the wave position that the base station will cover based on the location information of the ground wave position it currently covers and the location information of the terminal stored on the base station side, the terminal will be assigned to the first terminal set.

[0156] For any historical terminal that has been registered in the low-Earth orbit satellite communication system to which the base station belongs and has not yet been deregistered, the core network will send the terminal's identifier and historical location information to the satellite-borne base station that covers the terminal, based on the stored historical location information of the terminal. The satellite-borne base station that covers the terminal will then classify the terminal into the first terminal set.

[0157] When a base station schedules terminals that have initiated initial random access to it, if it finds that the terminal will be assigned to the second terminal set according to the terminal set determination criteria, it obtains the fifth distance between the terminal and each idle historical terminal assigned to the first terminal set.

[0158] If any fifth distance is greater than or equal to the first preset distance threshold, the terminal is converted to belong to the first terminal set and scheduled based on the first TDD frame structure.

[0159] Furthermore, the base station needs to receive the location measurement results reported by the terminal to the base station before it randomly accesses the base station. Specifically, before initiating random access to any satellite-based base station, if the terminal can access the terrestrial network, it automatically sends its current location measurement results to the wireless access node in the terrestrial network that it can access. The wireless access node then forwards the results to the satellite-ground cooperative network element in the terrestrial network that can interact with the satellite. Finally, based on the satellite-ground cooperative network element, the terminal's current location measurement results are sent to the satellite-based base station that can currently cover the terminal.

[0160] Similar to interference within a cell, regardless of which specific frame structure design is adopted, there will be no inter-UE interference between any two UEs in the same set of UEs using the same frame structure.

[0161] However, there is a possibility that one of the cell edge UEs in the set of UEs using the first TDD frame structure and the other of the cell edge UEs in the set of UEs using the second TDD frame structure may be receiving downlink data while the other is transmitting uplink data. If these two edge UEs located in different cells are close to each other, cross-link interference between UEs in the same channel will occur.

[0162] Figure 10 This is a schematic diagram illustrating an exemplary implementation of a satellite communication method based on a Time Division Duplex (TDD) frame structure design, as shown in this application. This embodiment mainly introduces a method for avoiding cross-link interference between "a cell edge UE in a UE set using the first TDD frame structure" and "a cell edge UE in a neighboring cell set using the second TDD frame structure" based on geographic area fencing. Figure 10 As shown, this satellite communication method based on the Time Division Duplex (TDD) frame structure includes the following steps:

[0163] S1001, determine the preset time division duplex (TDD) frame structure group corresponding to the base station, wherein the preset TDD frame structure group includes a first TDD frame structure and a second TDD frame structure generated after offsetting the frame header of the first TDD frame structure.

[0164] Regarding the specific implementation of step S1001, there are three design schemes for the preset TDD frame structure group. Please refer to the specific description of the relevant part in step S101 in the above embodiment, which will not be repeated here.

[0165] S1002, in response to receiving the first message sent by the terminal, the coverage area of ​​the base station is divided into an outer circle and an inner circle according to the boundary of the coverage area of ​​the base station and a first preset distance threshold, wherein the minimum distance between the dividing line of the outer circle and the inner circle and the boundary of the coverage area of ​​the base station is at least greater than or equal to the first preset distance threshold.

[0166] Centered on the sub-satellite point, the coverage area of ​​the cell is logically divided into inner and outer rings based on the distance to the sub-satellite point; the outer ring is equivalent to walking inward from the boundary of the cell coverage area with a value equal to the first preset distance threshold. Figure 11 This application illustrates a schematic diagram of dividing the coverage area of ​​a base station into an outer ring and an inner ring.

[0167] S1003, determine whether the terminal is located within the outer ring of the base station's coverage area based on the terminal's location information.

[0168] S1004 If the terminal is located in the outer ring of the base station's coverage area, then the terminal is determined to belong to the first terminal set, thereby avoiding cross-link interference between terminals in adjacent cells.

[0169] S1005, if the terminal is located within the inner circle of the base station's coverage area, then further determine the terminal set to which the terminal belongs, wherein the terminal set is either the first terminal set or the second terminal set.

[0170] S1006, If the terminal belongs to the first terminal set, the terminal is scheduled based on the first TDD frame structure.

[0171] S1007, If the terminal belongs to the second terminal set, schedule the terminal based on the second TDD frame structure.

[0172] In this embodiment, for UEs that have initiated initial random access, each satellite base station, based on the geographical location information reported by these UEs, schedules UEs located in the outer ring of the cell to use only the first TDD frame structure, while only UEs located in the inner ring of the cell use both frame structures to improve air interface resource utilization. By ensuring that each idle UE chooses the timing of initiating initial random access using the first TDD frame structure, any UE initiating initial random access at the edge of a cell will naturally not cause inter-UE interference to UEs in neighboring cells that have initiated initial random access.

[0173] Furthermore, the cells projected onto the ground by LEO satellites fall into three possible modes: earth-moving cells, earth-fixed cells (also referred to as staring cells in some literature), and quasi-earth-fixed cells. An earth-moving cell is one where the cell projected onto the ground moves with the satellite (in this case, the satellite's antenna is generally perpendicular to the ground); an earth-fixed cell is one where the cell projected onto the ground is stationary relative to the ground (the satellite needs to adjust its antenna pointing angle to cover a given area during its movement); and a quasi-earth-fixed cell is one where the satellite can only provide fixed-point coverage of a given area on the ground for a certain period (i.e., it is in the state of an earth-fixed cell), but after this period expires, the cell projected onto the ground will move with the satellite (i.e., it becomes an earth-moving cell).

[0174] When the target cell projected by the base station corresponds to the ground mobile cell mode or the ground quasi-stationary cell mode, for each second terminal in the second terminal set, if it is detected that it has changed from being located in the inner circle of the base station's coverage area to being located in the outer circle of the base station's coverage area based on its location information, then the terminal set to which it belongs is changed to the first terminal set.

[0175] Furthermore, this application also allows for mutual coordination between adjacent satellite-based base stations via inter-satellite links. The specific implementation method is as follows:

[0176] Receive neighboring cell terminal location information sent by neighboring base stations. The neighboring cell terminal location information is the location information corresponding to the terminal that has been classified into the first terminal set or the second terminal set by the neighboring base stations, or the location information corresponding to the terminal that has been classified into the first terminal set or the second terminal set by the neighboring base stations and is located at the edge position of the corresponding neighboring cell.

[0177] Based on the location information of terminals classified into the first terminal set or the second terminal set by the base station and the location information of neighboring terminals, at least one terminal equipment group to be subject to sub-band level frequency division scheduling is determined. The terminal equipment group includes at least one terminal classified into the first or second terminal set by the base station and at least one neighboring terminal classified into the first or second terminal set by an adjacent base station.

[0178] The specific method for determining at least one group of terminal devices to be subject to subband-level frequency division scheduling is as follows: Based on the location information of terminals classified into the first or second terminal set by the base station and the location information of neighboring cells, calculate the fourth distance between each terminal classified into the first or second terminal set by the base station and each terminal classified into the first or second terminal set by adjacent base stations; or calculate the fourth distance between each terminal classified into the first or second terminal set by the base station and located at the edge position of the current cell and each terminal classified into the first or second terminal set by adjacent base stations and located at the edge position of the corresponding neighboring cell. If any terminal classified by a base station into the first terminal set or the second terminal set has a fourth distance less than a first preset distance threshold with any neighboring terminal classified by an adjacent base station into the first terminal set or the second terminal set, then the terminal and the neighboring terminal become members of a terminal device group; or if any terminal classified by a base station into the first terminal set or the second terminal set and located at the edge position of the cell has a fourth distance less than a first preset distance threshold with any neighboring terminal classified by an adjacent base station into the first terminal set or the second terminal set and located at the edge position of the corresponding neighboring cell, then the terminal and the neighboring terminal become members of a terminal device group.

[0179] In conjunction with adjacent base stations, a sub-band level frequency division scheduling scheme is used to schedule the terminals included in the terminal equipment group.

[0180] Furthermore, in this application, when applying the designed frame structure scheme, the adaptation design required for the SSB transmission scheme is described.

[0181] The first design option is one that does not require any changes to the existing 3GPP NR protocol.

[0182] Before initiating initial random access, all idle UEs receive CD-SSB (which is the SSB used to define the cell, also known as the SSB that can be used for cell access when we usually talk about SSB) according to the predetermined SSB transmission time.

[0183] After a UE initiates initial random access, for any UE scheduled to use the second TDD frame structure, it is made to listen to the NCD-SSB (i.e., the SSB that cannot be used to define the cell, the full English name is Non-cell-defining SSB) to complete the required RRM, RLM and BFD measurements.

[0184] The base station transmits NCD-SSBs with the same frame header offset, wherein the frame header offset corresponding to the NCD-SSB is the same as the frame header offset corresponding to the second TDD frame structure. Each terminal in the second terminal set receives the NCD-SSB to complete the required radio link measurement.

[0185] The NCD-SSB period is set to be greater than or equal to the CD-SSB period (this is in accordance with the 3GPP NR protocol).

[0186] Note: NCD-SSB is called "SSB that cannot be used to define a cell" because the MIB messages in NCD-SSB do not include information related to SIB1 (specifically, the MIB messages in NCD-SSB do not include CORESET#0 and Type 0-PDCCH CSS, which are used to enable the UE to receive / decode SIB1 messages).

[0187] The second design option involves modifying the existing 3GPP NR protocol.

[0188] In the efficient TDD frame structure design presented in this paper, regardless of the specific design, the offset of the frame header is the sum of the number of DL time slots and UL time slots in the first TDD frame structure. If we denote "the sum of the number of DL time slots and UL time slots in the first TDD frame structure" as M, the design modification can be described as follows: If we take the frame header of the first TDD frame structure as the starting point for counting, the satellite base station transmits CD-SSBs in the 1st time slot, the 2nd time slot, the (M+1)th time slot, and the (M+2)th time slot. Figure 12 This diagram illustrates the CD-SSB transmission slots using the first frame structure group design as an example, where M equals the number of GP slots N, based on... Figure 12 The specific frame structure example shown (frame period is 10ms, N=10) describes the modifications to the SSB transmission scheme as follows: If the design is based on the SSB transmission scheme named case C in the 3GPP 5G protocol, the 3GPP 5G protocol stipulates that CD-SSB should be transmitted in the first four time slots of every 20ms duration (i.e., every two radio frames). Here, in order to adapt to our proposed "base station uses the first TDD frame structure and the second TDD frame structure to schedule a portion of UEs in the cell", it can be changed to let CD-SSB be transmitted in the first two time slots of every 20ms duration and in the M+1th time slot (11th time slot) and the M+2th time slot (12th time slot).

[0189] Furthermore, this application also proposes optimizations to the "initial reporting time of GNSS measurement results." Specifically:

[0190] According to the current version of the 3GPP protocol, after the initial random access is completed, the UE communicates with the core network via NAS messages to complete identity recognition, authentication, and encryption. Then, it completes security mode authentication and queries and reports GNSS measurement results via the air interface. Next comes the querying and reporting of UE capabilities. In other words, after the initial random access procedure is completed (i.e., after the transmission of Msg5), the idle-state UE still needs to go through some other message transmissions before it can report its GNSS measurement results (i.e., its own geographical location information) for the first time.

[0191] To achieve better interference avoidance through geographical isolation (especially when using geographical isolation to avoid inter-UE interference caused by the first random access message of the UE initiating initial random access to the UE after initiating initial random access), we recommend that the terminal's GNSS measurement results be included in the first message (Msg1 / MsgA) sent by the idle UE when it initiates initial random access (that is, the "first reporting time of GNSS measurement results" should be advanced to the "sending time of the first message in the initial random access procedure").

[0192] If the first message in the initial random access procedure is Msg1 (i.e., the initial random access uses a four-step random access): regarding the method by which GNSS measurement results are carried and sent to the base station along with the PRACH preamble sequence in Msg1, it can be referred to the method in the two-step random access procedure where "PUSCH and PRACH preamble sequence are carried and sent to the base station along with MsgA"; in other words, GNSS measurement results will be carried and sent to the base station along with the PRACH preamble sequence in accordance with the pre-configured time and frequency resources (i.e., unlicensed scheduling) broadcast in the system message.

[0193] If the first message in the initial random access procedure is MsgA (i.e., the initial random access uses a two-step random access): simply add the GNSS measurement results as part of the PUSCH in MsgA.

[0194] Figure 13 This is a schematic diagram of an exemplary implementation of a satellite communication method based on a time-division duplex (TDD) frame structure design, as shown in this application, applied to a user terminal (UE). The satellite communication method based on the time-division duplex (TDD) frame structure design includes the following steps:

[0195] S1301, send the first message corresponding to the terminal to the base station.

[0196] Optionally, the first message is the message in which the terminal reports the location measurement results corresponding to the terminal for the first time after completing the initial random access.

[0197] Optionally, the first message is the first message sent by the terminal to the base station when initiating initial random access.

[0198] The user terminal (UE) sends a first message corresponding to the terminal to the base station. Correspondingly, after receiving the first message sent by the terminal, the base station determines the terminal set to which the terminal belongs based on a preset first criterion.

[0199] S1302, the receiving base station schedules the terminal based on the first TDD frame structure or the second TDD frame structure, wherein the second TDD frame structure is generated by offsetting the frame header of the first TDD frame structure.

[0200] If the terminal belongs to the first terminal set, the receiving base station schedules the terminal based on the first TDD frame structure.

[0201] If the terminal belongs to the second terminal set, the receiving base station schedules the terminal based on the second TDD frame structure.

[0202] The first terminal set is a set of terminals that are invoked to use the first TDD frame structure.

[0203] The second terminal set is a set of terminals that are invoked to use the second TDD frame structure.

[0204] In this embodiment of the application, within a cell, based on the classification and scheduling of UEs by the satellite base station, a portion of the ground UEs adopt the first TDD frame structure, while the TDD frame structure of another portion of the ground UEs adopts the frame header offset version of the first TDD frame structure, i.e., the second TDD frame structure. Furthermore, all (or part) of the DL and UL time slots in the second TDD frame structure correspond to the GP time slots of the first TDD frame structure (i.e., they occur at the same time). At the same time, this naturally also causes all (or part) of the DL and UL time slots in the first TDD frame structure to correspond to the GP time slots of the second TDD frame structure. This allows the satellite base station to communicate with the other portion of UEs during the waiting period of communication with a portion of the UEs (i.e., during the GP time period of the corresponding frame structure), thereby improving the air interface resource utilization of the entire system.

[0205] Optionally, the first message is the message in which the terminal reports its location measurement results for the first time after completing initial random access. The TDD frame structure configuration information carried by the base station in the first system message broadcast is the configuration information corresponding to the first TDD frame structure. After the base station receives the first message among all messages sent by the terminal before sending the first message, if the terminal is not currently assigned to the first terminal set or the second terminal set, it is determined that the terminal belongs to the first terminal set. The reporting time of the message in which the terminal reports its location measurement results for the first time is after the terminal has completed initial random access and completed identity recognition, authentication and encryption with the core network through the non-access stratum (NAS), and completed the security mode control process with the base station through air interface interaction.

[0206] Optionally, the first message is the first message sent by the terminal to the base station when initiating initial random access. The first report of the location measurement result corresponding to the terminal is sent to the base station along with the first message using the time and frequency resources pre-configured in the system message. The TDD frame structure configuration information carried by the base station in the first system message broadcast is the configuration information corresponding to the first TDD frame structure. The terminal uses the timing of the first TDD frame structure to send the first message.

[0207] If the first message is the first message sent by the terminal to the base station when initiating initial random access, the method for determining whether the first message is sent and the corresponding frame structure when the first message is sent includes: receiving a first system message broadcast by the base station, wherein the TDD frame structure configuration information carried by the base station in the first system message is the configuration information corresponding to the first TDD frame structure; receiving a second system message broadcast by the base station, wherein the second system message broadcast by the base station carries the location information of terminals already assigned to the second terminal set in the current position covered by the beam carrying the second system message, and the location information of terminals already assigned to the second terminal set in each adjacent position whose nearest distance from the boundary of the current position is less than or equal to a first preset distance threshold; the terminal base station Based on the first system message, the second system message, the terminal's own location measurement result, and the first preset distance threshold broadcast by the base station, it is determined whether the current initiation of initial random access will cause inter-terminal co-channel cross-link interference to nearby terminals already assigned to the second terminal set; if the determination result is that it will not cause inter-terminal interference to nearby terminals in the second terminal set, the terminal uses the timing of the first TDD frame structure to send the first message; if the determination result is that it will cause inter-terminal interference to at least one nearby terminal in the second terminal set, the terminal temporarily does not send the first message; if the first message is to be sent, the first report of the terminal's corresponding location measurement result is sent to the base station along with the first message using the time and frequency resources pre-configured in the system message.

[0208] If the first message is the first message sent by the terminal to the base station when initiating initial random access, the method for determining whether the first message is sent and the corresponding frame structure when the first message is sent includes: receiving a first system message broadcast by the base station, wherein the TDD frame structure configuration information carried by the first system message includes configuration information corresponding to the first TDD frame structure and configuration information of the frame header offset required to generate the second TDD frame structure; receiving a second system message broadcast by the base station, wherein the second system message carries the location information of terminals already assigned to the first terminal set and the second terminal set in the current 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 in each adjacent position whose nearest distance from the boundary of the current position is less than or equal to a first preset distance threshold; the terminal, based on the first system message, the second system message, the terminal's own location measurement results, and the first preset distance threshold, determines whether the current initiation of initial random access will affect the neighboring terminals already assigned to the first or second terminal set. If the combined terminals cause inter-terminal cross-link interference in the shared channel, and the determination result is that there will be no inter-terminal interference to the neighboring terminals in the first terminal set and the second terminal set, then the terminal uses the timing of the first TDD frame structure or the second TDD frame structure to send the first message; if the determination result is that there will be inter-terminal interference to the neighboring terminals in the first terminal set, but no inter-terminal interference to the neighboring terminals in the second terminal set, then the terminal uses the timing of the first TDD frame structure to send the first message; if the determination result is that there will be inter-terminal interference to the neighboring terminals in the second terminal set, but no inter-terminal interference to the neighboring terminals in the first terminal set, then the terminal uses the timing of the second TDD frame structure to send the first message; if the determination result is that there will be inter-terminal interference to at least one neighboring terminal in the first terminal set and at least one neighboring terminal in the second terminal set, then the terminal will temporarily not send the first message; if the first message is to be sent, then the first report of the location measurement result corresponding to the terminal is sent to the base station along with the first message using the time and frequency resources pre-configured in the system message.

[0209] Furthermore, after the base station adopts a sub-band-level frequency division scheduling scheme to avoid potential inter-terminal co-channel cross-link interference between certain terminals using different frame structures, if co-channel cross-link interference does occur between those terminals, the inter-terminal co-channel sub-band cross-link interference remaining on the terminal side after adopting sub-band-level frequency division scheduling is eliminated based on one or more of the interference elimination schemes in the spatial domain, the analog domain, and the digital domain.

[0210] Figure 14 This is a schematic diagram of a satellite communication device based on a time-division duplex (TDD) frame structure design proposed in an embodiment of this application.

[0211] like Figure 14 As shown, the satellite communication device 1400 based on the time division duplex (TDD) frame structure is suitable for network equipment and includes: a determination module 1401, a judgment module 1402, a first scheduling module 1403, and a second scheduling module 1404.

[0212] The determining module 1401 is configured to determine the preset time division duplex (TDD) frame structure group corresponding to the base station. The preset TDD frame structure group includes a first TDD frame structure and a second TDD frame structure generated after offsetting the frame header of the first TDD frame structure.

[0213] The judgment module 1402 is configured to, in response to receiving a first message sent by a terminal, determine the terminal set to which the terminal belongs, wherein the terminal set is either a first terminal set or a second terminal set;

[0214] The first scheduling module 1403 is configured to schedule the terminal based on the first TDD frame structure if the terminal belongs to the first terminal set.

[0215] The second scheduling module 1404 is configured to schedule the terminal based on the second TDD frame structure if the terminal belongs to the second terminal set.

[0216] Figure 15 This is a schematic diagram of another satellite communication device based on the time division duplex (TDD) frame structure proposed in this application.

[0217] like Figure 15 As shown, the satellite communication device 1500 based on the time division duplex (TDD) frame structure is suitable for user terminal (UE) and includes: a transmitting module 1501 and a receiving scheduling module 1502.

[0218] The sending module 1501 is configured to send the first message corresponding to the terminal to the base station;

[0219] The receiving scheduling module 1502 is used as a module and is configured to receive the scheduling of the terminal by the base station based on the first TDD frame structure or the second TDD frame structure, wherein the second TDD frame structure is generated by offsetting the frame header of the first TDD frame structure.

[0220] According to embodiments of this application, this application also provides a communication device and a readable storage medium.

[0221] like Figure 16As shown, the communication device includes one or more processors 1601, a memory 1602, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components are interconnected via different buses and can be mounted on a common motherboard or otherwise as required. The processors can process instructions executed within the communication device, including instructions stored in or on memory to display graphical information of a GUI on an external input / output device (such as a display device coupled to the interface). In other embodiments, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple communication devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 16 Take the 1601 processor as an example.

[0222] The memory 1602 is the non-transitory computer-readable storage medium provided in this application. The memory stores instructions executable by at least one processor to cause the at least one processor to execute the satellite communication method based on the time-division duplex (TDD) frame structure design provided in this application. The non-transitory computer-readable storage medium of this application stores computer instructions for causing a computer to execute the satellite communication method based on the time-division duplex (TDD) frame structure design provided in this application.

[0223] The memory 1602, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the satellite communication method based on the time-division duplex (TDD) frame structure design in the embodiments of this application. The processor 1601 executes various server functions and data processing by running the non-transitory software programs, instructions, and modules stored in the memory 1602, thereby implementing the satellite communication method based on the time-division duplex (TDD) frame structure design in the above method embodiments.

[0224] Memory 1602 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the positioning communication device. Furthermore, memory 1602 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. Optionally, memory 1200 may include memory remotely located relative to processor 1601, and these remote memories can be connected to the positioning communication device via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0225] The communication device may further include an input device 1603 and an output device 1604. The processor 1601, memory 1602, input device 1603, and output device 1604 can be connected via a bus or other means. Figure 16 Taking the example of a connection between China and Israel via a bus.

[0226] Input device 1603 can receive input numerical or character information, and generate key signal inputs related to user settings and function control of the positioning communication device, such as touch screens, keypads, mice, trackpads, touchpads, pointers, one or more mouse buttons, trackballs, joysticks, etc. Output device 1604 may include display devices, auxiliary lighting devices (e.g., LEDs), and haptic feedback devices (e.g., vibration motors). The display device may include, but is not limited to, liquid crystal displays (LCDs), light-emitting diode (LED) displays, and plasma displays. In some embodiments, the display device may be a touch screen.

[0227] Various implementations of the systems and techniques described herein can 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 implementations may include: implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transferring data and instructions to the storage system, the at least one input device, and the at least one output device.

[0228] These computational programs (also referred to as programs, software, software applications, or code) include machine instructions for a programmable processor and can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. As used herein, the terms “machine-readable medium” and “computer-readable medium” refer to any computer program product, device, and / or apparatus (e.g., disk, optical disk, memory, programmable logic device (PLD)) used to provide machine instructions and / or data to a programmable processor, including machine-readable media that receive machine instructions as machine-readable signals. The term “machine-readable signal” refers to any signal used to provide machine instructions and / or data to a programmable processor.

[0229] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device for displaying information to the user (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor); and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the computer. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0230] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as a data server), or computing systems that include middleware components (e.g., an application server), or computing systems that include frontend components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with embodiments of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of 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.

[0231] Computer systems can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. Client-server relationships are created by computer programs running on the respective computers and having a client-server relationship with each other.

[0232] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this application can be achieved, and this is not limited herein.

Claims

1. A satellite communication method based on Time Division Duplex (TDD) frame structure design, applied to network equipment, characterized in that, include: Determine the preset time-division duplex (TDD) frame structure group corresponding to the base station, wherein the preset time-division duplex (TDD) frame structure group includes a first TDD frame structure and a second TDD frame structure generated after offsetting the frame header of the first TDD frame structure; In response to receiving a first message sent by a terminal, determine the terminal set to which the terminal belongs, wherein the terminal set is a first terminal set or a second terminal set; If the terminal belongs to the first terminal set, the terminal is scheduled based on the first TDD frame structure; If the terminal belongs to the second terminal set, the terminal is scheduled based on the second TDD frame structure.

2. The method according to claim 1, characterized in that, Also includes: The first TDD frame structure is configured such that the number of guard interval (GP) slots in the first TDD frame structure is N, and the sum of the number of downlink (DL) slots and uplink (UL) slots in the first TDD frame structure is equal to N. The frame header of the first TDD frame structure is offset by N time slots to obtain the second TDD frame structure, 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 preset time-division duplex TDD frame structure group is generated based on the first TDD frame structure and the second TDD frame structure.

3. The method according to claim 1, characterized in that, Also includes: The first TDD frame structure is configured such that the number of GP slots in the first TDD frame structure is N, and the sum of the number of DL slots and UL slots in the first TDD frame structure is less than N. The first TDD frame structure is offset by a frame header to obtain the second TDD frame structure, wherein all DL time slots and all UL time slots in the second TDD frame structure correspond to a portion of the GP time slots in the first TDD frame structure. The preset time-division duplex TDD frame structure group is generated based on the first TDD frame structure and the second TDD frame structure.

4. The method according to claim 1, characterized in that, Also includes: The first TDD frame structure is configured such that the number of GP slots in the first TDD frame structure is N, and the sum of the number of DL slots and UL slots in the first TDD frame structure is greater than N. The first TDD frame structure is offset by a frame header to obtain the second TDD frame structure, wherein some of the time slots in 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 there are conflicting time slots between the first TDD frame structure and the second TDD frame structure. The preset time-division duplex TDD frame structure group is generated based on the first TDD frame structure and the second TDD frame structure.

5. The method according to claim 4, characterized in that, The method further includes: Set the conflict slot located on the first TDD frame structure to silent; or... Set the conflict slot located on the second TDD frame structure to silent.

6. The method according to claim 4, characterized in that, The method further includes: For the conflicting time slots, when the base station performs scheduling, frequency division multiplexing with sub-band full-duplex technology is used to receive uplink data from terminals scheduled by the base station to use one of the first TDD frame structures and the second TDD frame structures, and to transmit downlink data from terminals scheduled by the base station to use the other of the first TDD frame structures and the second TDD frame structures.

7. The method according to claim 6, characterized in that, After the reception of uplink data for terminals scheduled by the base station to use one of the first TDD frame structures and the second TDD frame structure, and the transmission of downlink data for terminals scheduled by the base station to use the other of the first TDD frame structures and the second TDD frame structure, are performed using sub-band full-duplex frequency division multiplexing technology at the sub-band level, the method further includes: Based on one or more of the interference cancellation schemes in the spatial domain, the analog domain, and the digital domain, interference cancellation is performed on two types of inter-subband interference remaining on the network side, including base station self-interference and cross-link interference between common sub-bands of base stations.

8. The method according to claim 1, characterized in that, The method further includes: When there is inter-terminal cross-link interference between any first terminal belonging to the first terminal set and any second terminal belonging to the second terminal set, a sub-band-level frequency division scheduling scheme is adopted to avoid interference.

9. The method according to claim 1, characterized in that, The step of determining the terminal set to which the terminal belongs in response to receiving the first message sent by the terminal includes: Obtain a set of first location information corresponding to each first terminal in the first terminal set, wherein the first terminal is in a connected state with the base station; Obtain a second location information set corresponding to each second terminal in the second terminal set, wherein the second terminal is in a connected state with the base station; Obtain the terminal location information corresponding to the terminal; 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.

10. The method according to claim 9, characterized in that, The step of determining the terminal set to which the terminal belongs based on the first location information set, the second location information set, and the terminal location information includes: Based on the first location information set and the terminal location information, the minimum distance among the distances between the terminal and each first terminal in the first terminal set is obtained as the first distance; Based on the second location information set and the terminal location information, the minimum distance among the distances between the terminal and each second terminal in the second terminal set is obtained as the second distance; The first distance, the second distance, and a first preset distance threshold are compared to determine the terminal set to which the terminal belongs.

11. The method according to claim 10, characterized in that, The step of comparing the first distance, the second distance, and a first preset distance threshold to determine the terminal set to which the terminal belongs includes: If both the first distance and the second distance are greater than or equal to the first preset distance threshold, then it is determined that the terminal belongs to the first terminal set or that the terminal belongs to the second terminal set. If the first distance is greater than or equal to the first preset distance threshold and the second distance is less than the first preset distance threshold, then the terminal is determined to belong to the first terminal set. If the first distance is less than the first preset distance threshold and the second distance is greater than or equal to the first preset distance threshold, then the terminal is determined to belong to the second terminal set; If both the first distance and the second distance are less than the first preset distance threshold, then the terminal set to which the terminal belongs is determined based on the preset terminal set determination criteria.

12. The method according to claim 11, characterized in that, The method for determining the terminal set to which the terminal belongs based on a preset terminal set determination criterion includes, but is not limited to: The terminal set to which the terminal belongs is determined based on the balance criterion of the number of terminals in the first terminal set and the second terminal set; or, The terminal set to which the terminal belongs is determined based on the criterion of randomly selecting one of the terminals.

13. The method according to claim 12, characterized in that, If both the first distance and the second distance are less than the first preset distance threshold, after determining the terminal set to which the terminal belongs based on the preset terminal set determination criteria, the method further includes: If the terminal set 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 in the first terminal set whose distance value from the terminal is less than the first preset distance threshold is obtained, and a sub-band-level frequency division scheduling scheme is adopted to avoid co-channel cross-link 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, then based on the second location information set and the terminal location information, a second terminal subset in the second terminal set whose distance value from the terminal is less than the first preset distance threshold is obtained, and a sub-band-level frequency division scheduling scheme is adopted to avoid co-channel cross-link interference between the terminal and each terminal in the second terminal subset.

14. The method according to claim 13, characterized in that, The method further includes: 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, the terminal set corresponding to the terminal that reported the location update information is re-determined based on the location update information.

15. The method according to claim 14, characterized in that, The method further includes: When re-determining the terminal set corresponding to the terminal that reported the location update information based on the location update information, the terminal set to which at least one terminal in the first terminal set and the second terminal set belongs that did not report the location update information is modified, so that the number of terminals in the updated first terminal set and the second terminal set that need to use a sub-band level frequency division scheduling scheme to avoid cross-link interference between terminals can be minimized.

16. The method according to claim 1, characterized in that, The step of determining the terminal set to which the terminal belongs in response to receiving the first message sent by the terminal includes: Based on the boundary of the coverage area of ​​the base station and a first preset distance threshold, the coverage area of ​​the base station is divided into an outer circle and an inner circle, wherein the minimum distance between the dividing line between the outer circle and the inner circle and the boundary of the coverage area of ​​the base station is at least greater than or equal to the first preset distance threshold. Based on the terminal location information of the terminal, determine whether the terminal is located within the outer ring of the coverage area of ​​the base station; If the terminal is located in the outer ring of the coverage area of ​​the base station, then the terminal is determined to belong to the first terminal set, thereby avoiding cross-link interference between terminals in adjacent cells. If the terminal is located within the inner circle of the coverage area of ​​the base station, the terminal set to which the terminal belongs is determined according to a preset terminal set determination criterion; or, a first location information set corresponding to each first terminal in the first terminal set is obtained, and the first terminal is connected to the base station, a second location information set corresponding to each second terminal in the second terminal set is obtained, and the second terminal is connected to the base station, and the terminal location information corresponding to the terminal is obtained; and the terminal set to which the terminal belongs is determined based on the first location information set, the second location information set, and the terminal location information; wherein, the terminal set is either the first terminal set or the second terminal set.

17. The method according to claim 16, characterized in that, The method further includes: When the target cell projected by the base station corresponds to the ground mobile cell mode or the ground quasi-stationary cell mode, for each second terminal in the second terminal set, if it is detected that it has changed from being located in the inner circle of the coverage area of ​​the base station to being located in the outer circle of the coverage area of ​​the base station, then the terminal set to which it belongs is changed to the first terminal set.

18. The method according to claim 1, characterized in that, The method further includes: A frame header offset is performed on the Synchronization and Broadcast Signal Block (NCD-SSB) that cannot be used to define a cell, wherein the frame header offset corresponding to the NCD-SSB is the same as the frame header offset corresponding to the second TDD frame structure, and each terminal in the second terminal set receives the NCD-SSB to complete the required radio link measurement.

19. The method according to claim 1, characterized in that, The step of determining the terminal set to which the terminal belongs in response to receiving the first message sent by the terminal includes: In response to receiving the first message sent by the terminal, the terminal set to which the terminal belongs is determined according to a preset terminal set determination criterion.

20. The method according to claim 1, characterized in that, The first message is the message in which the terminal reports its location measurement results for the first time after completing initial random access. The method further includes: The TDD frame structure configuration information carried by the base station in the first system message broadcast is the configuration information corresponding to the first TDD frame structure. Furthermore, after the base station receives the first message among all messages sent by the terminal before sending the first message, if the terminal is not currently assigned to either the first terminal set or the second terminal set, then the terminal is determined to belong to the first terminal set. The message for the first reporting of the location measurement result corresponding to the terminal is sent after the terminal has completed initial random access and completed identity recognition, authentication and encryption with the core network through the non-access stratum (NAS), and completed the security mode control process with the base station through air interface interaction.

21. The method according to claim 1, characterized in that, The first message is the first message sent by the terminal to the base station when initiating initial random access. The method also... include: The initial reporting of the location measurement result corresponding to the terminal is sent to the base station along with the first message using time-frequency resources pre-configured in the system message; The TDD frame structure configuration information carried by the base station in the first system message broadcast is the configuration information corresponding to the first TDD frame structure, and the terminal uses the timing of the first TDD frame structure to send the first message.

22. The method according to claim 20, characterized in that, The method further includes: When the base station performs downlink time-frequency resource scheduling for any terminal belonging to the second terminal set, it determines the slot index of the UL slot configured to transmit the random access preamble sequence in the first TDD frame structure. Obtain the time slot index of multiple consecutive DL time slots within a preset time slot range in the second TDD frame structure, which are located away from the UL time slot in the first TDD frame structure that is configured to transmit a random access preamble sequence therein; When performing frequency domain resource scheduling for each DL time slot in a plurality of consecutive DL time slots within a preset time slot range in the second TDD frame structure, sub-band-level frequency division scheduling is implemented with the air interface resources configured for initial random access to terminals in the first terminal set.

23. A satellite communication method based on Time Division Duplex (TDD) frame structure design, applied to a user terminal (UE), characterized in that, include: Send the first message corresponding to the terminal to the base station; The terminal receives scheduling from the base station 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 of the first TDD frame structure. The scheduling of the terminal by the base station based on a first TDD frame structure or a second TDD frame structure includes: in response to receiving a first message sent by the terminal, the base station determines the terminal set to which the terminal belongs; if the terminal belongs to the first terminal set, the base station schedules the terminal based on the first TDD frame structure; if the terminal belongs to the second terminal set, the base station schedules the terminal based on the second TDD frame structure.

24. The method according to claim 23, characterized in that, The first message is the first message sent by the terminal to the base station when it initiates initial random access. The first report of the location measurement result corresponding to the terminal is sent to the base station along with the first message using time and frequency resources pre-configured in the system message. The TDD frame structure configuration information carried by the base station in the first system message broadcast is the configuration information corresponding to the first TDD frame structure, and the terminal uses the timing of the first TDD frame structure to send the first message.

25. A satellite communication device based on a time-division duplex (TDD) frame structure design, characterized in that, Applicable to network devices, the apparatus includes at least one processor and a memory communicatively connected to the at least one processor; The memory stores instructions that can be executed by the at least one processor. The processor is configured to execute the following instructions: Determine the preset time-division duplex (TDD) frame structure group corresponding to the base station, wherein the preset time-division duplex (TDD) frame structure group includes a first TDD frame structure and a second TDD frame structure generated after offsetting the frame header of the first TDD frame structure; In response to receiving a first message sent by a terminal, determine the terminal set to which the terminal belongs, wherein the terminal set is a first terminal set or a second terminal set; If the terminal belongs to the first terminal set, the terminal is scheduled based on the first TDD frame structure; If the terminal belongs to the second terminal set, the terminal is scheduled based on the second TDD frame structure.

26. A satellite communication device based on a time-division duplex (TDD) frame structure design, characterized in that, The device, applicable to a user terminal (UE), includes at least one processor and a memory communicatively connected to the at least one processor. The memory stores instructions that can be executed by the at least one processor. The processor is configured to execute the following instructions: Send the first message corresponding to the terminal to the base station; The terminal receives scheduling from the base station 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 of the first TDD frame structure. The scheduling of the terminal by the base station based on a first TDD frame structure or a second TDD frame structure includes: in response to receiving a first message sent by the terminal, the base station determines the terminal set to which the terminal belongs; if the terminal belongs to the first terminal set, the base station schedules the terminal based on the first TDD frame structure; if the terminal belongs to the second terminal set, the base station schedules the terminal based on the second TDD frame structure.

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