Satellite communication method based on time division duplexing (TDD) frame structure design, and apparatus

Abstract

The present application provides a satellite communication method and apparatus based on a time division duplex (TDD) frame structure design and relates to the technical field of wireless communication. According to the method, a pre-set time division duplex (TDD) frame structure group corresponding to a base station is determined, wherein the pre-set TDD frame structure group includes a first TDD frame structure and a second TDD frame structure generated by performing a frame header offset on the first TDD frame structure, and in response to receiving a first message transmitted from a terminal, a set of terminals to which the terminal belongs is determined, wherein the set of terminals is either a first set of terminals or a second set of terminals, and if the terminal belongs to the first set of terminals, scheduling is performed for the terminal based on the first TDD frame structure, and if the terminal belongs to the second set of terminals, scheduling is performed for the terminal based on the second TDD frame structure. According to the present application, when communication with some UEs enters a standby period (i.e., a GP period of the frame structure), a satellite-based base station can communicate with other UEs, thereby improving the air interface resource utilization rate of the entire system.

Description

Technology Field

[0001] The present 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, both the systems already in use in orbit and the international standards for 5G Non-Terrestrial Networks (NTN) under 3GPP are considering adopting Frequency Division Duplex (FDD) as the satellite-to-ground user link. However, considering the scarcity of available spectrum resources in FDD systems (especially within the spectrum range below 6 GHz) and the reduced spectrum utilization due to asymmetric uplink traffic, which is the mainstream traffic type in FDD systems, the industry is currently actively seeking to apply Time Division Duplexing (TDD) to satellite-to-ground user links.

[0003] According to the relevant technology, in order to fully utilize time-domain resources based on the TDD method, different cells projected onto the ground by different satellite-borne base stations can perform data transmission and reception by alternately using GP (Guard Period) slots between different cells. However, this method is not sufficient to improve resource utilization, and there is a problem in that only one satellite-borne base station in the entire system can communicate with some user terminals (User Equipment, abbreviated as UE) during each duration of a GP slot belonging to a certain cell, whereas a more ideal situation in which all satellite-borne base stations in the system can communicate with some UEs during each duration of a GP slot belonging to a certain cell is not achieved. The problem to be solved

[0004] The present application provides a satellite communication method and apparatus based on a time-division duplex (TDD) frame structure design that can improve the overall air interface resource utilization rate of the system by enabling a satellite-based base station to communicate with some UEs when communication with some UEs enters a standby period (i.e., the GP period of the frame structure). means of solving the problem

[0005] According to an embodiment of the first aspect of the present application, a satellite communication method based on a time-division duplex (TDD) frame structure design used in a network device comprises: determining a pre-set time-division duplex (TDD) frame structure group corresponding to a base station, wherein the pre-set TDD frame structure group includes a first TDD frame structure and a second TDD frame structure generated by performing a frame header offset on the first TDD frame structure; in response to receiving a first message transmitted from a terminal, determining a set of terminals to which the terminal belongs, wherein the set of terminals is a first set of terminals or a second set of terminals; if the terminal belongs to the first set of terminals, performing scheduling for the terminal based on the first TDD frame structure; and if the terminal belongs to the second set of terminals, performing scheduling for the terminal based on the second TDD frame structure.

[0006] In an embodiment of the present application, based on classification and scheduling of UEs by a satellite-based base station within a cell, some terrestrial UEs use a first TTD frame structure, and the TDD frame structure of other terrestrial UEs uses a frame header offset version of the first TTD frame structure, i.e., a second TDD frame structure. In addition, all (or some) of the DL and UL slots in the second TDD frame structure correspond to the GP slots in the first TDD frame structure (i.e., occur at the same time), and naturally, all (or some) of the DL and UL slots in the first TDD frame structure correspond to the GP slots in the second TDD frame structure. Thus, when communication with some UEs enters a waiting period (i.e., the GP period of the corresponding frame structure), the satellite-based base station can communicate with other UEs, thereby improving the air interface resource utilization rate of the entire system.

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

[0008] According to an embodiment of the third aspect of the present application, a satellite communication device based on a time-division duplex (TDD) frame structure design applied to a network device is provided, comprising: a determination module configured to determine a pre-set time-division duplex (TDD) frame structure group corresponding to a base station, wherein the pre-set TDD frame structure group includes a first TDD frame structure and a second TDD frame structure generated by performing a frame header offset on the first TDD frame structure; a determination module configured to determine a set of terminals to which the terminal belongs in response to receiving a first message transmitted from a terminal, wherein the set of terminals is a first set of terminals or a second set of terminals; a first scheduling module configured to perform scheduling on the terminal based on the first TDD frame structure when the terminal belongs to the first set of terminals; and a second scheduling module configured to perform scheduling on the terminal based on the second TDD frame structure when the terminal belongs to the second set of terminals.

[0009] According to an embodiment of the fourth aspect of the present application, a satellite communication device based on a time division duplex (TDD) frame structure design applied to a user terminal (UE) comprises: a transmitting module configured to transmit a first message corresponding to the terminal to a base station; and a scheduling receiving module used in the module and configured to receive scheduling for the terminal based on a first TDD frame structure or a second TDD frame structure from the base station, wherein the second TDD frame structure is generated by performing a frame header offset on the first TDD frame structure.

[0010] According to an embodiment of the fifth aspect of the present application, a communication device comprises: at least one processor; and a memory connected to the communication of the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor, thereby enabling the at least one processor to execute a satellite communication method based on a time-division duplex (TDD) frame structure design described in an embodiment of the first aspect of the present application or a satellite communication method based on a time-division duplex (TDD) frame structure design described in an embodiment of the second aspect of the present application.

[0011] According to an embodiment of the sixth aspect of the present application, a computer storage medium is provided, wherein instructions executable by a computer are stored therein, and the satellite communication method based on a time-division duplex (TDD) frame structure design described in an embodiment of the first aspect of the present application or the satellite communication method based on a time-division duplex (TDD) frame structure design described in an embodiment of the second aspect of the present application is implemented by executing said computer-executable instructions by a processor. Brief explanation of the drawing

[0012] FIG. 1 is a schematic diagram illustrating an exemplary embodiment of a satellite communication method based on a time division duplex (TDD) frame structure design according to an embodiment of the present application. FIG. 2(a) is a schematic diagram of a first TDD frame structure in which the sum of the number of DL slots and the number of UL slots according to the present application is equal to the number of GP slots N. FIG. 2(b) is a schematic diagram of a frame structure timing sequence on the base station side generated by offsetting the frame header of the first TDD frame structure according to the present application by N slots. FIG. 3(a) is a schematic diagram of a first TDD frame structure in which the sum of the number of DL slots and the number of UL slots according to the present application is smaller than the number of GP slots N. FIG. 3(b) is a schematic diagram of a frame structure timing sequence on the base station side generated by performing frame header offsetting on the first TDD frame structure according to the present application. FIG. 4(a) is a schematic diagram of a first TDD frame structure in which the sum of the number of DL slots and the number of UL slots according to the present application is greater than the number of GP slots N. FIG. 4(b) is a schematic diagram of a frame structure timing sequence on the base station side generated by performing a frame header offset on a first TDD frame structure according to the present application. FIG. 5 is a schematic diagram illustrating frequency division multiplexing with a subband granularity by subband full-duplex technology according to the present application. FIG. 6 is a schematic diagram illustrating the occurrence of same-channel cross-link interference between UEs according to the present application. FIG. 7 is a schematic diagram illustrating an exemplary embodiment of a satellite communication method based on a time division duplex (TDD) frame structure design according to the present application. FIG. 8 is a schematic diagram illustrating the occurrence of same-channel cross-link interference between UEs according to the present application. FIG. 9 is a schematic diagram illustrating an exemplary embodiment of a satellite communication method based on a time-division duplex (TDD) frame structure design according to the present application. FIG. 10 is a schematic diagram illustrating an exemplary embodiment of a satellite communication method based on a time division duplex (TDD) frame structure design according to the present application. FIG. 11 is a schematic diagram illustrating the division of a base station coverage area into an outer circle and an inner circle according to the present application. FIG. 12 is a schematic diagram illustrating the determination of the transmission slot of a CD-SSB using the first frame structure group design method as an example. FIG. 13 is a schematic diagram illustrating an exemplary embodiment of a satellite communication method based on a time division duplex (TDD) frame structure design according to the present application. FIG. 14 is a schematic diagram of the structure of a satellite communication device based on a time division duplex (TDD) frame structure design according to an embodiment of the present application. FIG. 15 is a schematic diagram of the structure of a satellite communication device based on a different time division duplex (TDD) frame structure design according to an embodiment of the present application. FIG. 16 is a schematic diagram of a communication device according to an embodiment of the present application. Specific details for implementing the invention

[0013] Hereinafter, embodiments of the present application will be described in detail. Examples of the embodiments are illustrated in the drawings, wherein identical or similar components or components having identical or similar functions are indicated by identical or similar reference numerals. The embodiments described below with reference to the attached drawings are illustrative and merely for the purpose of interpreting the present application; the present application should not be understood as being limited thereto.

[0014] According to related technology, among the frame formats used for the normal operation of the TDD system, the GP (Guard Period) required for the transition between the DL (Downlink) slot and the UL (Uplink) slot is the "round-trip time of signal propagation between the base station and the cell remote point (RTT)" radius "It shall be stated as..." and must be greater than or equal to. When applying the TDD method to the satellite-ground user link of a low-orbit satellite, considering the long signal propagation distance between the satellite and the ground user terminal (User Equipment, abbreviated as UE), RTT radius As the size of the degree increases, the duration of the GP also becomes very long. As the GP becomes longer, the overall system air interface resource utilization rate decreases.

[0015] For example, in the case of low-orbit satellite systems, RTT radius The magnitude of is approximately 5 milliseconds (abbreviated as ms). Generally, GP is RTT radius Since it can be set to be the same as, in this case, GP is equal to 5ms. If the subcarrier interval used is 30kHz (i.e., the duration of each slot is 0.5ms), then between the DL slot and the UL slot, there must be 10 special slots where all are GP (in the following description, special slots where all are GP are referred to as "GP slots").

[0016] In some methods, in order to fully utilize time-domain resources according to the TDD method, different cells projected onto the ground by different satellite-based base stations can perform data transmission and reception by alternately using GP (Guard Period) slots between different cells. However, the following problems exist with this method.

[0017] 1. This approach is insufficient in terms of improving resource utilization, and while only one satellite-based base station in the entire system can communicate with some user terminals (User Equipment, abbreviated as UE) during each duration of a GP slot belonging to a cell, a more ideal situation is not achieved where all satellite-based base stations in the system can communicate with some UEs during each duration of a GP slot belonging to a cell.

[0018] 2. Furthermore, when the above method is used, there is a possibility that a situation may occur where one UE is performing downlink reception while the other UE is performing uplink transmission, between "any UE located at the cell edge in one cell" and "any edge UE in a cell adjacent to that cell." Therefore, if the distance between the edge UEs located in the two different cells is close, "co-channel cross-link interference between UEs" will occur. If such interference cannot be effectively avoided, the above method cannot be implemented.

[0019] 3. In addition, when this method is used, it is necessary to slide the starting position of the system frame in different cells and then offset it, so the requirement for temporal synchronization between adjacent satellites is very strict.

[0020] 4. In addition, regarding the ratio between the number of DL slots, UL slots, and GP slots, there is no universal and normative design, and this is merely an example.

[0021] To solve the above technical problem, an embodiment of the present application provides a satellite communication method and apparatus based on a time division duplex (TDD) frame structure design as follows.

[0022] FIG. 1 is a schematic diagram illustrating an exemplary embodiment of a satellite communication method based on a time-division duplex (TDD) frame structure design according to the present application. As illustrated in FIG. 1, the satellite communication method based on the time-division duplex (TDD) frame structure design used in a network device comprises the following steps.

[0023] In S101, a preset time division duplex (TDD) frame structure group corresponding to a base station is determined, wherein the preset TDD frame structure group includes a first TDD frame structure and a second TDD frame structure generated by performing a frame header offset on the first TDD frame structure.

[0024] In this application, the design methods of the following three preset TDD frame structure groups are listed for selection.

[0025] According to the first implementable frame structure design method, the method for obtaining a pre-set TDD frame structure group includes the following: A first TDD frame structure is established, wherein the number of guard section (GP) slots of the first TDD frame structure is N (where N is a positive integer), and the sum of the number of downlink (DL) slots and the number of uplink (UL) slots according to the first TDD frame structure is equal to N, and FIG. 2(a) is a schematic diagram of a first TDD frame structure according to the present application in which the sum of the number of DL slots and the number of UL slots is equal to the number of GP slots N, and based on FIG. 2(a), a second TDD frame structure is obtained by offsetting the frame header of the first TDD frame structure by N slots, and FIG. 2(b) is a schematic diagram of a frame structure timing sequence on the base station side generated by offsetting the frame header of the first TDD frame structure according to the present application by N slots, and as shown in FIG. 2(b), all DL slots and all UL slots according to the second TDD frame structure correspond to all GP slots according to the first TDD frame structure, and the satellite-based base station simultaneously utilizes the first TDD frame structure and the second TDD frame structure to each of some UEs It can be scheduled, and after determining the first TDD frame structure and the second TDD frame structure, a pre-configured group of TDD frame structures is created based on the first TDD frame structure and the second TDD frame structure.

[0026] According to the first frame structure design implementation method, satellite-based base stations can always communicate with some UEs, and there is absolutely no "must-be on standby" period.

[0027] According to the first frame structure design implementation method, the network side ensures that no collisions occur in the upward and downward directions in any slot, and does not introduce any additional new interference.

[0028] In the second implementable frame structure design method, the method for obtaining a pre-set TDD frame structure group includes the following: A first TDD frame structure is established, wherein the number of GP slots of the first TDD frame structure is N, and the sum of the number of DL slots and the number of UL slots according to the first TDD frame structure is less than N, and FIG. 3(a) is a schematic diagram of a first TDD frame structure according to the present application in which the sum of the number of DL slots and the number of UL slots is less than the number of GP slots N, and based on FIG. 3(a), a second TDD frame structure is obtained by performing a frame header offset on the first TDD frame structure, and FIG. 3(b) is a schematic diagram of a frame structure timing sequence on the base station side generated by performing a frame header offset on the first TDD frame structure according to the present application, and as shown in FIG. 3(b), all DL slots and all UL slots according to the second TDD frame structure correspond to some GP slots of the first TDD frame structure, and the satellite-based base station can schedule some UEs respectively by using the first TDD frame structure and the second TDD frame structure simultaneously, and the first TDD frame structure and the second TDD frame structure have been determined Afterwards, a pre-configured group of TDD frame structures is created based on the first TDD frame structure and the second TDD frame structure.

[0029] According to the second frame structure design implementation method, the satellite-based base station cannot always perform communication with some UEs, in other words, there is a period where it "must wait," and as exemplified in FIG. 3(b), two consecutive slot periods are wasted.

[0030] According to the second frame structure design implementation method, the network side ensures that no collisions occur in the upward and downward directions in any slot, and does not introduce any additional new interference.

[0031] According to the third implementable frame structure design method, the method for obtaining a pre-set TDD frame structure group includes the following: A first TDD frame structure is established, wherein the number of GP slots of the first TDD frame structure is N, and the sum of the number of DL slots and the number of UL slots of the first TDD frame structure exceeds N, and FIG. 4(a) is a schematic diagram of a first TDD frame structure according to the present application in which the sum of the number of DL slots and the number of UL slots exceeds the number of GP slots N, and based on FIG. 4(a), a second TDD frame structure is obtained by performing a frame header offset on the first TDD frame structure, and FIG. 4(b) is a schematic diagram of a frame structure timing sequence on the base station side generated by performing a frame header offset on the first TDD frame structure according to the present application, and as shown in FIG. 4(b), some slots among all DL slots and all UL slots in the second TDD frame structure correspond to all GP slots in the first TDD frame structure, and collision slots exist between the first TDD frame structure and the second TDD frame structure, and the satellite-based base station uses the first TDD frame structure and the second TDD frame structure simultaneously Each can schedule some UEs and create a pre-configured group of TDD frame structures based on the first TDD frame structure and the second TDD frame structure.

[0032] According to the third frame structure design implementation method, as shown in FIG. 4(b), two DL slots of each frame cycle in the second TDD frame structure collide with two UL slots of each frame cycle in the first TDD frame structure in the upward and downward directions, and the two slots are designated as colliding slots.

[0033] According to the third frame structure design implementation method, satellite-based base stations can always communicate with some UEs, meaning there is no "must-wait" period.

[0034] In S102, in response to receiving a first message transmitted from a terminal, the set of terminals to which the terminal belongs is determined, wherein the set of terminals is the first set of terminals or the second set of terminals.

[0035] Here, the first set of terminals is a set of terminals scheduled to use the first TDD frame structure.

[0036] Here, the second set of terminals is a set of terminals scheduled to use the second TDD frame structure.

[0037] Optionally, the first message may be a message that first reports a location measurement result corresponding to the terminal after the terminal has completed initial random access.

[0038] Optionally, the first message may be the first message transmitted to the base station when the terminal initiates initial random access.

[0039] When a base station receives a first message transmitted from a terminal, it determines the terminal set to which the terminal belongs based on a predetermined terminal set determination criterion. The terminal set determination criterion includes, but is not limited to, a terminal number equalization criterion or a dice roll random criterion.

[0040] In S103, if the terminal belongs to the first set of terminals, scheduling is performed on the terminal based on the first TDD frame structure.

[0041] In S104, if the terminal belongs to the second set of terminals, scheduling is performed on the terminal based on the second TDD frame structure.

[0042] In an embodiment of the present application, based on classification and scheduling of UEs by a satellite-based base station within a cell, some terrestrial UEs use a first TTD frame structure, and the TDD frame structure of other terrestrial UEs uses a frame header offset version of the first TTD frame structure, i.e., a second TDD frame structure. In addition, all (or some) of the DL and UL slots in the second TDD frame structure correspond to the GP slots in the first TDD frame structure (i.e., occur at the same time), and naturally, all (or some) of the DL and UL slots in the first TDD frame structure correspond to the GP slots in the second TDD frame structure. Thus, when communication with some UEs enters a waiting period (i.e., the GP period of the corresponding frame structure), the satellite-based base station can communicate with other UEs, thereby improving the air interface resource utilization rate of the entire system.

[0043] Based on the above embodiment, in actual use, when a pre-set TDD frame structure group adopts the third frame structure design method shown in FIG. 4(b), the following two methods may be adopted to prevent interference from being introduced to the network side.

[0044] 1. According to an implementable method for preventing interference from being introduced to the first network side, a collision slot located in the first TDD frame structure can be set to silent or a collision slot located in the second TDD frame structure can be set to silent.

[0045] Based on this silence processing, no additional interference is newly introduced to the network side. Furthermore, as expected, there is no period during which the base station "must remain in a standby state." Consequently, some UEs lose a small amount of downstream (or upstream) communication opportunities. Therefore, while the overall system air interface resource utilization is improved, it cannot be considered an optimal method. Taking the specific frame structure exemplified in Fig. 4(b) as an example, in a single specific process, two DL slots among the collision slots of each frame cycle in the second TDD frame structure can be set to silence (i.e., DL scheduling is not performed for all UEs using the second TDD frame structure in the said two slots). This is because UEs scheduled to use the second TDD frame structure in this manner may lose a small amount of DL reception opportunities in each frame cycle. Therefore, when performing scheduling, UEs with a relatively low demand for downstream data volume are given priority in using the second TDD frame structure, depending on the downstream data volume for different users.

[0046] 2. According to an implementable method for preventing interference from being introduced to the second network side, in order to prevent interference from being introduced to the network side, when the base station performs scheduling for a collision slot, it may be selected to perform frequency division multiplexing with a subband granularity by using subband full-duplex technology for the reception of uplink data from a terminal using one of the first and second TDD frame structures scheduled by the base station and for the transmission of downlink data from a terminal using the other of the first and second TDD frame structures scheduled by the base station (for reference, according to the definition of Re1-18, "subband full-duplex" means that only the duplex operation performed on the base station side is enhanced, while the terminal side maintains a half-duplex operation). FIG. 5 is a schematic diagram illustrating frequency division multiplexing with a subband granularity using subband full-duplex technology according to the present application.

[0047] For example, in the specific frame structure illustrated in FIG. 4(b), for each of the two slots where a collision occurs, when performing scheduling, the satellite-based base station performs frequency division multiplexing with a subband granularity by using subband full-duplex technology for receiving uplink data from a terminal using a first TDD frame structure scheduled by the base station and transmitting downlink data from a terminal using a second TDD frame structure scheduled by the base station.

[0048] By using subband full-duplex technology for the reception of uplink data from a terminal scheduled by the base station using either the first or second TDD frame structure, and for the transmission of downlink data from a terminal scheduled by the base station using the other of the first or second TDD frame structure, frequency division multiplexing with subband granularity is performed. Subband-to-subband interference remaining at the base station includes "gNB's self interference" and "gNB-to-gNB co-channel inter-subband cross-link interference." For both of the above interferences, an interference avoidance method examined for "subband full-duplex" in Re1-18 can be used, thereby achieving a good interference avoidance effect. As a specific interference avoidance method, interference cancellation can be performed for two types of inter-subband interference remaining on the network side, including base station self-interference and cross-link interference between same-channel subbands between base stations, through one or more of the following methods: interference cancellation methods in the spatial domain (e.g., adding transmit / receive antenna separation and antenna isolation design), interference cancellation methods in the analog domain (e.g., adding an analog high rectangular coefficient filter to enhance filtering function), and interference cancellation methods in the digital domain (e.g., signal processing for interference cancellation performed through transmission information).

[0049] Regardless of which of the three implementable frame structures mentioned above is used, no interference occurs between any two UEs within a set of UEs using the same frame structure. Below, we will analyze in more detail the "UE-to-UE co-channel cross-link interference" that may exist between UEs applying the first TDD frame structure and UEs applying the second TDD frame structure.

[0050] 1. When using the first frame structure design method exemplified in FIG. 2(b), the second frame structure design method exemplified in FIG. 3(b), and the third frame structure design method exemplified in FIG. 4(b), and when applying a silence processing method to cases where up-down collisions occur in some slots on the network side (collision slots),

[0051] In the case of a terrestrial network, there will be no co-channel cross-link interference between UEs using the first TDD frame structure and UEs using the second TDD frame structure within the cell. Meanwhile, FIG. 6 is a schematic diagram disclosing the occurrence of co-channel cross-link interference between UEs according to the present application. As shown in FIG. 6, due to an excessively long propagation distance on the satellite-terrestrial link, there is a possibility that a situation may occur in which one UE among "a set of UEs using the first TDD frame structure (i.e., the first set of terminals)" and "a set of UEs using the second TDD frame structure (i.e., the second set of terminals)" are performing downlink reception while the other UE is performing uplink transmission. If the distance between the two UEs is close at this time, co-channel cross-link interference between UEs will occur.

[0052] 2. When the third frame structure design method exemplified in FIG. 4(b) is used and an implementable method to prevent interference from being introduced to the second network side in the event that uplink-downlink collisions occur in some slots on the network side (collision slots), for example, when applying a subband full-duplex processing method,

[0053] In both terrestrial and LEO satellite networks, co-channel cross-link interference exists between UEs using the first TDD frame structure and UEs using the second TDD frame structure within a cell. In such cases, since collisions occur in the upstream and downstream directions in a small number of slots on the network side, these collisions can be resolved through subband full-duplex technology.

[0054] Regarding co-channel cross-link interference between UEs within a cell that may occur between "any one UE among the set of UEs using the first TDD frame structure (i.e., the first terminal set)" and "any one UE among the set of UEs using the second TDD frame structure (i.e., the second terminal set)," interference avoidance countermeasures are designed for each of the two cases: co-channel cross-link interference that may exist between "UEs after initial random access is initiated" and co-channel cross-link interference that may exist between "a UE that is initiating initial random access" and "UE after initial random access is initiated" within the cell.

[0055] FIG. 7 is a schematic diagram of an exemplary embodiment of a satellite communication method based on a time-division duplex (TDD) frame structure design according to the present application. In this embodiment, a method for avoiding co-channel cross-link interference that may exist between "UEs after initiating initial random access" is introduced, primarily by a subband-level frequency division scheduling scheme. As illustrated in FIG. 7, the satellite communication method based on the time-division duplex (TDD) frame structure design comprises the following steps.

[0056] In S701, a preset time division duplex (TDD) frame structure group corresponding to a base station is determined, wherein the preset TDD frame structure group includes a first TDD frame structure and a second TDD frame structure generated by performing a frame header offset on the first TDD frame structure.

[0057] In S702, in response to receiving a first message transmitted from a terminal, the set of terminals to which the terminal belongs is determined, wherein the set of terminals is the first set of terminals or the second set of terminals.

[0058] In S703, if a terminal belongs to the first set of terminals, scheduling is performed on the terminal based on the first TDD frame structure.

[0059] In S704, if the terminal belongs to the second set of terminals, scheduling is performed on the terminal based on the second TDD frame structure.

[0060] Regarding the specific implementation method of steps S701 to S704, since the specific description of the part related to steps S101 to S104 in the above embodiment can be referred to, a redundant description will be omitted.

[0061] In S705, if there is inter-terminal same-channel cross-link interference between any one first terminal belonging to the first terminal set and any one second terminal belonging to the second terminal set, interference avoidance is performed through a subband-level frequency division scheduling method.

[0062] Below, we introduce two cases regarding interference avoidance through subband-level frequency division scheduling.

[0063] 1. When using the first frame structure design method, the second frame structure design method, and when using the third frame structure design method and applying a silence processing method to cases where uplink and downlink collisions occur on the network side in some slots,

[0064] Since no collisions occur in the upstream and downstream directions on the network side, subband-level frequency division scheduling was performed; however, the transmit and receive operations at any given point in time at the base station are not equivalent to "subband full-duplex," and there is no "base station self-interference" or "cross-link interference between base stations within the same channel subband" on the base station side.

[0065] When "UE-to-UE co-channel inter-subband cross-link interference" remains between terminals after sub-band level frequency division isolation is performed on the UE side, as a specific interference avoidance method, a method capable of implementing a good interference avoidance effect, such as the "sub-band full-duplex" reviewed in Re1-18, may be used, and interference cancellation may be performed through one or more methods among a spatial domain interference cancellation method (e.g., separation of transmitting and receiving antennas and addition of antenna isolation design), an analog domain interference cancellation method (e.g., addition of an analog high-rectangular coefficient filter to improve filtering function), and a digital domain interference cancellation method (e.g., signal processing for interference cancellation performed through transmission information). FIG. 8 is a schematic diagram illustrating the occurrence of co-channel inter-subband cross-link interference between UEs according to the present application.

[0066] 2. When using the third frame structure design method and applying the subband full-duplex processing method to cases where uplink and downlink collisions occur in some slots on the network side,

[0067] In this case, some of the collision slots where uplink and downlink collisions occur on the network side have already naturally implemented subband-level frequency division scheduling because they themselves use the "subband full-duplex" method. For other slots, subband-level frequency division scheduling can be specifically performed again. At the base station, the transmit / receive operation at any point in time among the aforementioned other slots is not equivalent to "subband full-duplex."

[0068] If "UE-to-UE co-channel inter-subband cross-link interference" remains between terminals after subband-level frequency division isolation is performed on the UE side, a specific interference avoidance method capable of achieving good interference avoidance effects, such as the "subband full-duplex" method examined in Re1-18, may be used. Furthermore, interference cancellation may be performed through one or more of the following methods: a spatial domain interference cancellation method (e.g., separation of transmit and receive antennas and addition of antenna isolation design), an analog domain interference cancellation method (e.g., addition of an analog high-rectangular coefficient filter to enhance filtering capabilities), and a digital domain interference cancellation method (e.g., signal processing for interference cancellation performed through transmission information).

[0069] FIG. 9 is a schematic diagram illustrating an exemplary embodiment of a satellite communication method based on a time-division duplex (TDD) frame structure design according to the present application. In this embodiment, a method for avoiding co-channel cross-link interference that may exist between "UEs after initiating initial random access" is introduced primarily through geographical isolation. As illustrated in FIG. 9, the satellite communication method based on the time-division duplex (TDD) frame structure design comprises the following steps.

[0070] In S901, a preset time division duplex (TDD) frame structure group corresponding to a base station is determined, wherein the preset TDD frame structure group includes a first TDD frame structure and a second TDD frame structure generated by performing a frame header offset on the first TDD frame structure.

[0071] Regarding the specific implementation method of Step S901, there are a total of three pre-set design methods for TDD frame structure groups. Since the specific description of the relevant part of Step S101 according to the above embodiment can be referenced, redundant descriptions will be omitted.

[0072] In S902, in response to receiving a first message transmitted from a terminal, a first set of location information corresponding to each first terminal among a first set of terminals is obtained, and the first terminal and the base station are in a connected state.

[0073] Here, the first set of terminals may be a set of terminals scheduled to use the first TDD frame structure.

[0074] Each terminal within the first set of terminals is referred to as the first terminal. The location information of each first terminal is designated as the first location information, and a first set of location information is created based on all of the first location information.

[0075] Optionally, when the first terminal reports a conventional measurement report message, it may also report its own location information, so that the base station stores the last reported location information from the first terminal and, if necessary, the base station can retrieve it from its own memory.

[0076] Optionally, the base station can explicitly and in real-time query the location information of the first terminal through a "terminal information request message".

[0077] Optionally, the first terminal may specifically report its own location information periodically or in a manner based on an event trigger (e.g., detecting that a change in distance due to its own change in location has exceeded a threshold), and the base station may store at least the last reported location information from the first terminal and, if necessary, retrieve it from its own memory.

[0078] In S903, a second set of location information corresponding to each second terminal among the second set of terminals is obtained, and the second terminal and the base station are in a connected state.

[0079] Here, the second set of terminals may be a set of terminals scheduled to use the second TDD frame structure.

[0080] Each terminal within the second set of terminals is designated as a second terminal. Location information of each second terminal is obtained as second location information, and a second set of location information is generated based on all second location information.

[0081] In S904, terminal location information corresponding to the terminal is obtained.

[0082] Terminal location information corresponding to the terminal transmitting the first message is obtained, that is, terminal location information corresponding to the terminal scheduled by determining whether it is a first TDD frame structure or a second TDD frame structure by the base station is obtained.

[0083] In S905, the set of terminals to which the terminal belongs is determined based on the first set of location information, the second set of location information, and the terminal location information.

[0084] In the LEO satellite system, each UE can report its own geographical location information to a satellite-based base station via GNSS ("BeiDou system").

[0085] Since the cell of each LEO satellite system has a considerably large ground coverage area (reaching hundreds of thousands to over a million square kilometers), there is a sufficiently large geographical space in each cell, and the distance between any two UEs within the cell is large enough to effectively avoid mutual interference between UEs.

[0086] For easy understanding, the base station scheduling some UEs within a cell using two frame structures can be said to correspond to dividing the UEs within that cell into two sets of users.

[0087] Therefore, in order to avoid "co-channel cross-link interference between UEs" within a cell, when a base station performs scheduling, it may be considered to ensure that the geographical distance between "any one UE in a set of UEs using a first TDD frame structure" and "any one UE in a set of UEs using a second TDD frame structure" is greater than a first predetermined distance threshold.

[0088] Specifically, for any UE after initiating initial random access, when the base station determines whether the UE uses a first TDD frame structure or a second TDD frame structure, it first obtains the minimum distance among the distances between each first terminal in the first set of terminals and the first set of terminals as the first distance based on the first set of location information and terminal location information.

[0089] Based on the second set of location information and terminal location information, the minimum distance among the distances between each second terminal in the second set of terminals is obtained as the second distance.

[0090] The first distance and the second distance are compared with the first predetermined distance threshold to determine the set of terminals to which the terminal belongs. As a result of the determination, several situations as follows may occur.

[0091] If both the first distance and the second distance are greater than or equal to the first predetermined distance threshold, the base station allows the corresponding UE to use either the first TDD frame structure or the second TDD frame structure. That is, in such a case, interference between UEs can be avoided solely by geographical isolation. This allows it to be determined that a terminal belongs to the first set of terminals or that a terminal belongs to the second set of terminals.

[0092] If the first distance is greater than or equal to the first predetermined distance threshold and the second distance is less than the first predetermined distance threshold, it can be determined that the terminal belongs to the first set of terminals. That is, in such a case, interference between UEs can be avoided solely by geographical isolation.

[0093] If the first distance is less than the first predetermined distance threshold and the second distance is greater than or equal to the first predetermined distance threshold, it can be determined that the terminal belongs to the second set of terminals. That is, in such a case, interference between UEs can be avoided solely by geographical isolation.

[0094] If both the first distance and the second distance are less than the first predetermined distance threshold, that is, if interference between UEs cannot be avoided by geographical isolation alone, the terminal set to which the terminal belongs can be determined based on a predetermined terminal set determination criterion. When determining the terminal set to which the terminal belongs based on the predetermined terminal set determination criterion, the terminal set to which the terminal belongs is determined based on a criterion for balancing the number of terminals within the first terminal set and the second terminal set, or the terminal set to which the terminal belongs is determined based on a criterion for randomly selecting one of them, but is not limited thereto.

[0095] In S906, if a terminal belongs to the first set of terminals, scheduling is performed on the terminal based on the first TDD frame structure.

[0096] In S907, if the terminal belongs to the second set of terminals, scheduling is performed on the terminal based on the second TDD frame structure.

[0097] In an embodiment of the present application, based on classification and scheduling of UEs by a satellite-based base station within a cell, some terrestrial UEs use a first TTD frame structure, and the TDD frame structure of other terrestrial UEs uses a frame header offset version of the first TTD frame structure, i.e., a second TDD frame structure. In addition, all (or some) of the DL and UL slots in the second TDD frame structure correspond to the GP slots in the first TDD frame structure (i.e., occur at the same time), and naturally, all (or some) of the DL and UL slots in the first TDD frame structure correspond to the GP slots in the second TDD frame structure. Thus, when communication with some UEs enters a waiting period (i.e., the GP period of the corresponding frame structure), the satellite-based base station can communicate with other UEs, thereby improving the air interface resource utilization rate of the entire system.

[0098] Furthermore, if both the first distance and the second distance are less than the first predetermined distance threshold, after determining the terminal set to which the terminal belongs based on the predetermined terminal set judgment criteria,

[0099] When the terminal set to which the terminal belongs is a second terminal set, based on a first set of location information and terminal location information, a first terminal subset is obtained in which the distance value from the terminal in the first terminal set is less than a first predetermined distance threshold, and a step of avoiding same-channel cross-link interference between the terminal and each terminal in the first terminal subset through a subband-level frequency division scheduling method; and

[0100] When the terminal set to which the terminal belongs is the first terminal set, the method further includes the step of obtaining a second terminal subset in which the distance value from the terminal in the second terminal set is less than the first predetermined distance threshold based on the second location information set and terminal location information, and avoiding same-channel cross-link interference between the terminal and each terminal in the second terminal subset through a sub-band level frequency division scheduling method.

[0101] Furthermore, since the UE has mobility, the geographical distance between UEs may change. When location update information reported by any one of the first terminals in the first terminal set or any one of the second terminals in the second terminal set is received, the terminal set corresponding to the terminal reporting the location update information is determined again based on the location update information and in accordance with steps S902 to S905.

[0102] In addition, a more optimized processing as follows can be performed. That is, depending on changes in the distance between UEs, the base station can switch the frame structure used by one of the UEs between the first TDD frame structure and the second TDD frame structure at an appropriate timing. This makes it possible to avoid interference between UEs as much as possible solely through geographical isolation.

[0103] When redetermining the set of terminals corresponding to the terminal reporting the location update information based on the location update information, by changing the set of terminals to which at least one terminal among the first set of terminals and the second set of terminals that did not report the location update information belongs, the number of terminals that must avoid cross-link interference between terminals via a subband-level frequency division scheduling method among the first set of terminals and the second set of terminals after the update can be minimized.

[0104] Meanwhile, it should be noted that when using the first frame structure design method, the second frame structure design method, and the third frame structure design method, and when applying a silence processing method to cases where uplink and downlink collisions occur on the network side in some slots, "interference between UEs in the same channel cross-link" does not occur even when two UEs using different frame structures are in a situation where "one UE is performing downlink reception while the other UE is performing uplink transmission," provided that the distance between the two UEs is not close. Therefore, when using the first frame structure design method, the second frame structure design method, and the third frame structure design method, and when applying a silence processing method to cases where uplink and downlink collisions occur on the network side in some slots, "interference between UEs in the same channel cross-link" can be avoided through the geographical isolation method described in this embodiment.

[0105] Meanwhile, it should be noted that when the third frame structure design method is used and the network side applies a subband full-duplex processing method in cases where uplink and downlink collisions occur in some slots, since it was decided to perform subband full-duplex processing during scheduling for a small number of slots, "co-channel cross-link interference between UEs" inevitably exists between UEs using different frame structures at the point corresponding to some slots, regardless of whether they are geographically far or close. Therefore, when such a specific frame structure design is applied, avoiding "co-channel cross-link interference between UEs" through the geographical isolation method described in this embodiment is not appropriate and is not recommended. "Co-channel cross-link interference between UEs" can be avoided through the subband-level frequency division scheduling method described in the above embodiment.

[0106] Below, three feasible methods are introduced for avoiding co-channel cross-link interference that may exist between a "UE initiating initial random access" and a "UE after initiating initial random access" within a cell.

[0107] The reason such interference occurs is that, before a UE in an idle state initiates initial random access to a satellite-based base station, the base station cannot accurately determine the geographical location information of that UE, nor can it accurately determine which of the two frame structures the UE is using to transmit the first random access message (Msgl or MsgA) containing the PRACH preamble sequence (Physical Random Access Channel preamble sequence). Therefore, special countermeasures must be designed to avoid co-channel cross-link interference between UEs that occurs to the "UE after initiating initial random access" due to the first random access message from the "UE initiating initial random access."

[0108] First plan:

[0109] If the first message is a message that reports the location measurement result corresponding to the terminal for the first time after the terminal has completed initial random access, the TDD frame structure configuration information carried by the first system message broadcast by the base station is configuration information corresponding to the first TDD frame structure, and if the terminal is not currently assigned to the first terminal set or the second terminal set after the first message among all messages transmitted by the terminal before transmitting the first message is received by the base station, it is determined that the terminal belongs to the first terminal set. Here, the reporting time of the message for reporting the location measurement result corresponding to the terminal for the first time is after the terminal has completed initial random access, completed identity identification, authentication, and encryption with the core network through the Non-Access Layer (NAS), and completed the safe mode control process with the base station through air interface interaction.

[0110] When the first message is the first message transmitted to the base station when the terminal initiates initial random access, the first report regarding the location measurement result corresponding to the terminal is transmitted to the base station together with the first message using a preset time frequency resource among system messages, and the TDD frame structure configuration information carried in the first system message broadcast by the base station is configuration information corresponding to the first TDD frame structure, and the terminal transmits the first message using the timing sequence of the first TDD frame structure.

[0111] Regardless of whether the first message corresponds to either of the two messages above, when the base station in the present application performs downlink time-frequency resource scheduling for any one terminal belonging to the second set of terminals, it determines the slot index of a UL slot configured to transmit a random access preamble sequence in the first TDD frame structure, obtains the slot index of a plurality of consecutive DL slots in the second TDD frame structure whose distance from the UL slot configured to transmit a random access preamble sequence in the first TDD frame structure is within a preset slot range, and when performing frequency domain resource scheduling for each DL slot among the plurality of consecutive DL slots in the second TDD frame structure within the preset slot range, it implements subband-level frequency division scheduling together with an air interface resource configured for initial random access to the terminal in the first set of terminals. Specifically, each UE in an idle state selects a timing sequence using the first TDD frame structure to initiate initial random access (i.e., transmits Msgl of the 4th stage random access or MsgA of the 2nd stage random access using the timing sequence of the first TDD frame structure). At the same time, when the base station performs DL scheduling for UE(s) among the “set of UEs using the second TDD frame structure,” it minimizes the subband in the frequency domain for consecutive DL slots in the second TDD frame structure that are closest to the “UL slot capable of transmitting the random access preamble sequence in the first TDD frame structure,” thereby avoiding frequency domain resources corresponding to the PRACH occasion.If there is a UE in an idle state that starts initial random access, and there is a "UE(s) using a second TDD frame structure" that simultaneously performs DL reception at a location where the distance from the UE is less than the threshold of geographical isolation, then interference between subbands remaining in these "UE(s) using a second TDD frame structure" can be addressed by organically combining interference cancellation methods among the spatial domain, analog domain, and digital domains reviewed in Rel-18.

[0112] Theoretically, even if all UEs in the idle state select a timing sequence using the first TDD frame structure to initiate initial random access, it cannot be said that UEs in the connected state must necessarily use the timing sequence of the first TDD frame structure to initiate initial random access (there are cases where it is necessary to initiate initial random access even in the connected state, such as during a handover). Therefore, as a more reasonable approach, one can cite an example where the initial random access is initiated using the timing sequence of the frame structure currently in use (which then creates the possibility of initiating initial random access using the timing sequence of the second TDD frame structure). Accordingly, it is configured to broadcast the PRACH occasion in the second TDD frame structure as well. Then, theoretically, the PRACH occasions broadcast in the first TDD frame structure and the second TDD frame structure could be configured with different configurations, but a simpler and more efficient method is to cite an example where the PRACH occasions broadcast in both the first TDD frame structure and the second TDD frame structure are configured with the same configuration. Therefore, based on the assumption that they are "set with completely identical configurations," the above description did not distinguish between the PRACH occasion set in the "set of UEs using the first TDD frame structure" and the PRACH occasion set in the "set of UEs using the second TDD frame structure" when referring to the PRACH occasion.

[0113] Since there are many PRACH formats in which the transmission period of PRACH is 1 frame (i.e., in each wireless frame, a PRACH occasion exists during the UL slot period), "avoiding frequency domain resources corresponding to the PRACH occasion by making the subband in the frequency domain the smallest possible for the consecutive DL slots in the second TDD frame structure that are closest to the distance of the 'UL slot capable of transmitting a random access preamble sequence in the first TDD frame structure' as described above" is equivalent to performing frequency domain isolation at the subband level with respect to each group of consecutive DL slots in the first TDD frame structure with respect to the PRACH occasion.

[0114] In these avoidance measures, a terminal that is in an idle state and has not initiated initial random access to a base station does not belong to the first set of terminals, nor does it belong to the second set of terminals.

[0115] Second plan:

[0116] In the present application, when the first message is the first message transmitted to a base station when the terminal initiates initial random access, the first report of the location measurement result corresponding to the terminal is transmitted to the base station together with the first message using a preset time frequency resource among system messages, and the TDD frame structure setting information carried in the first system message broadcast by the base station is setting information corresponding to the first TDD frame structure.

[0117] At this time, as an implementable method, in a method for determining whether to transmit a first message and a frame structure corresponding when the first message is transmitted,

[0118] The TDD frame structure configuration information carried in the first system message broadcast by the base station is configuration information corresponding to the first TDD frame structure, and

[0119] The second system message broadcast by the base station carries location information of a terminal belonging to the second set of terminals among the current beam positions covered by the beam transmitting the second system message, and location information of a terminal belonging to the second set of terminals whose distance from the boundary of the current beam position among each adjacent beam position is less than or equal to the first predetermined distance threshold, and

[0120] The first system message and the second system message are used to determine whether inter-terminal co-channel cross-link interference occurs for terminals belonging to an adjacent second set of terminals as the terminal starts an initial random access based on the first system message and the second system message broadcast by the base station, the location measurement result of the terminal itself, and the first predetermined distance threshold.

[0121] As a result of the judgment, if it is determined that no inter-terminal interference occurs with respect to adjacent terminals among the second set of terminals, the terminal transmits a first message using the timing sequence of the first TDD frame structure, and

[0122] As a result of the judgment, if it is determined that inter-terminal interference occurs with respect to at least one adjacent terminal among the second set of terminals, the terminal does not temporarily transmit the first message, and

[0123] When the first message is transmitted, the first report of the location measurement result corresponding to the terminal includes the step of transmitting it to the base station together with the first message using a preset time frequency resource among system messages.

[0124] In such cases, as another implementable method, a method for determining whether to transmit a first message and a corresponding frame structure when the first message is transmitted,

[0125] The TDD frame structure configuration information carried in a first system message broadcast by a base station includes configuration information corresponding to a first TDD frame structure and configuration information for a frame header offset required to generate a second TDD frame structure, and

[0126] A second system message broadcast by a base station carries location information of terminals belonging to a first set of terminals and a second set of terminals at a current beam position covered by a beam including the second system message, and location information of terminals belonging to a first set of terminals and a second set of terminals at each adjacent beam position such that the distance closest to the boundary of the current beam position is less than or equal to a first predetermined distance threshold.

[0127] The first system message and the second system message are used to determine whether inter-terminal co-channel cross-link interference occurs for terminals belonging to an adjacent first set of terminals or second set of terminals as the terminal starts an initial random access, based on the first system message and the second system message broadcast by the base station, the location measurement result of the terminal itself, and a first predetermined distance threshold.

[0128] As a result of the judgment, if it is determined that no interference occurs between terminals with respect to adjacent terminals among the first set of terminals and the second set of terminals, the terminal transmits a first message using the timing sequence of the first TDD frame structure or the second TDD frame structure, and

[0129] As a result of the judgment, if it is determined that inter-terminal interference occurs with respect to adjacent terminals in the first set of terminals but not with respect to adjacent terminals in the second set of terminals, the terminal transmits the first message using the timing sequence of the first TDD frame structure, and

[0130] As a result of the judgment, if it is determined that inter-terminal interference occurs with respect to adjacent terminals in the second set of terminals but not with respect to adjacent terminals in the first set of terminals, the terminal transmits the first message using the timing sequence of the second TDD frame structure, and

[0131] As a result of the judgment, if it is determined that inter-terminal interference occurs between at least one adjacent terminal in the first set of terminals and at least one adjacent terminal in the second set of terminals, the terminal does not temporarily transmit the first message, and

[0132] When the first message is transmitted, when reporting the location measurement result corresponding to the terminal for the first time, the method includes the step of transmitting to the base station together with the first message using a preset time frequency resource among system messages.

[0133] In actual implementation, regarding the geographical location information of a terminal that needs to be broadcast by a base station, compression processing can be performed from different angles and / or through different methods before broadcasting to reduce the amount of data. For example, for each dimension of the three-dimensional geographical coordinates, the number of bytes for displaying information can be appropriately reduced, or two-dimensional geographical coordinates other than three-dimensional geographical coordinates can be used, or any suitable information compression algorithm can be specifically used.

[0134] In this plan, a terminal that is in an idle state and has not initiated initial random access to a base station does not belong to the first set of terminals, nor does it belong to the second set of terminals.

[0135] Third plan:

[0136] In the case where the first message is a message in which the terminal first reports a location measurement result corresponding to the terminal after completing an initial random access, the TDD frame structure configuration information carried in the first system message broadcast by the base station is configuration information corresponding to the first TDD frame structure, and before transmitting the first message, the terminal performs the transmission and reception of messages based on a timing sequence defined by the first TDD frame structure.

[0137] When the first message is the first message transmitted to the base station when the terminal initiates initial random access, or when the location measurement result corresponding to the terminal is reported for the first time, it utilizes a preset time frequency resource among system messages and transmits it to the base station together with the first message, and the TDD frame structure configuration information carried in the first system message broadcast by the base station is configuration information corresponding to the first TDD frame structure.

[0138] Regardless of whether the first message corresponds to either of the two types of messages mentioned above, if, after a past terminal that accessed the base station and entered a connection state in the present application is changed to an idle state, the base station discovers that the terminal is still in a beam position covered by the base station based on the location information of the ground beam position currently covered by itself and the location information stored on the base station side for the terminal, the terminal is assigned to the first set of terminals.

[0139] For any past terminal to which a base station belongs, which has completed registration in the low-orbit satellite communication system and whose registration has not been cancelled, the core network transmits the terminal's identifier and past location information to the satellite-based base station covering the terminal based on the stored past location information of the terminal, and the satellite-based base station covering the terminal assigns the terminal to the first set of terminals.

[0140] When the base station performs scheduling for a terminal that initiates initial random access to itself, if it discovers that the terminal belongs to a second set of terminals based on the terminal set determination criteria, it obtains a fifth distance between the terminal and each past terminal in an idle state belonging to the first set of terminals.

[0141] If any one of the fifth distances is greater than or equal to the first predetermined distance threshold, the terminal is changed to belong to the first set of terminals, and scheduling is performed based on the first TDD frame structure.

[0142] Furthermore, the base station needs to receive the location measurement result corresponding to the terminal that the terminal reported to the base station before the terminal randomly accesses the base station. Here, before the terminal initiates random access to a satellite-based base station, if the terminal can access a terrestrial network, the terminal automatically transmits the current location measurement result to an accessible wireless access node in the terrestrial network, transmits it through the wireless access node to a satellite-earth cooperative network element capable of exchanging information with a satellite in the terrestrial network, and then transmits the terminal's current location measurement result through the satellite-earth cooperative network element to a satellite-based base station capable of currently covering the terminal.

[0143] As with interference within a cell, regardless of whether any of the aforementioned specific frame structure designs are used, no interference occurs between any two UEs within a set of UEs using the same frame structure.

[0144] However, there exist cases where one UE is performing downlink reception while the other UE is performing uplink transmission, involving "a cell edge UE within a set of UEs using the first TDD frame structure" and "an edge UE within a set of UEs using the second TDD frame structure in adjacent cells." If the distance between the edge UEs located in these two different cells is short, co-channel cross-link interference between the UEs may occur.

[0145] FIG. 10 is a schematic diagram illustrating an exemplary embodiment of a satellite communication method based on a time-division duplex (TDD) frame structure design according to the present application. This embodiment introduces a method for avoiding co-channel cross-link interference between UEs, primarily through a geographical area fence, between "a cell edge UE of any one set of UEs using a first TDD frame structure" and "an edge UE of any one set of UEs using a second TDD frame structure among adjacent cells." As illustrated in FIG. 10, the satellite communication method based on the time-division duplex (TDD) frame structure design comprises the following steps.

[0146] In S1001, a preset time division duplex (TDD) frame structure group corresponding to a base station is determined, wherein the preset TDD frame structure group includes a first TDD frame structure and a second TDD frame structure generated by performing a frame header offset on the first TDD frame structure.

[0147] Regarding the specific implementation method of Step S1001, there are a total of three pre-set design methods for TDD frame structure groups. Since the specific description of the relevant part of Step S101 in the above embodiment can be referenced, redundant descriptions will be omitted.

[0148] In S1002, in response to receiving a first message transmitted from a terminal, the coverage area of ​​a base station is divided into an outer circle and an inner circle based on the boundary of the base station's coverage area and a first predetermined distance threshold, and the minimum distance between the boundary line of the outer circle and the inner circle and the boundary of the base station's coverage area is at least greater than the first predetermined distance threshold.

[0149] Centered on the point directly below the satellite, the coverage area of ​​the cell is theoretically divided into an outer circle and an inner circle based on the distance between the points directly below the satellite, and the outer circle corresponds to an area extending inward from the boundary line of the cell's coverage area by a distance equal to a first predetermined distance threshold. FIG. 11 is a schematic diagram of the coverage area of ​​a base station according to the present application divided into an outer circle and an inner circle.

[0150] In S1003, based on the terminal location information of the terminal, it is determined whether the terminal is located within the outer circle of the base station's coverage area.

[0151] In S1004, if the terminal is located within the outer circle of the base station's coverage area, it is determined that the terminal belongs to the first set of terminals, thereby avoiding same-channel cross-link interference between terminals in adjacent cells.

[0152] In S1005, if the terminal is located within the inner circle of the base station's coverage area, the terminal set to which the terminal belongs is further determined, wherein the terminal set is the first terminal set or the second terminal set.

[0153] In S1006, if the terminal belongs to the first set of terminals, scheduling is performed on the terminal based on the first TDD frame structure.

[0154] In S1007, if the terminal belongs to the second set of terminals, scheduling is performed on the terminal based on the second TDD frame structure.

[0155] In an embodiment of the present application, for "UES after initiating initial random access," when each satellite-based base station performs scheduling based on geographic location information reported by these UEs, the air interface resource utilization can be improved by allowing UEs located within the outer circle of the cell to use only the first TDD frame structure and UEs located within the inner circle of the cell to use both frame structures. If all UEs in an idle state select a timing sequence using the first TDD frame structure to start initial random access, any "UE initiating initial random access" located at the edge of a cell naturally does not cause interference between UEs with respect to "UES after initiating initial random access" located at the edge of an adjacent cell.

[0156] Furthermore, there are three types of cells projected onto the ground by LEO satellites: Earth-moving cells, Earth-fixed cells (also referred to as Starling cells in various literatures), and QuaSi-Earth-fixed cells. An Earth-moving cell refers to a cell projected onto the ground that moves along with the satellite (in this case, the satellite's antenna is generally perpendicular to the ground). An Earth-fixed cell refers to a cell projected onto the ground that is fixed relative to the ground (the satellite needs to adjust the antenna's pointing angle during movement to complete coverage of a pre-set area). A QuaSi-Earth-fixed cell refers to a state where the satellite can perform fixed pointing coverage over a pre-set area on the ground within a certain period (i.e., achieving the state of an Earth-fixed cell), but after this period has elapsed, the cell projected onto the ground moves along with the satellite (i.e., achieving the state of an Earth-moving cell).

[0157] If a target cell projected by a base station corresponds to a mobile Earth cell mode or a similar fixed Earth cell mode, for each second terminal in a second set of terminals, if it is detected that the location has changed from within the inner circle of the base station's coverage area to within the outer circle of the base station's coverage area based on the location information of the second terminal, the set of terminals to which the second terminal belongs is changed to a first set of terminals.

[0158] Furthermore, in this application, adjacent base stations can cooperate with each other through a satellite link. The specific implementation method is as follows.

[0159] Receive adjacent cell terminal location information transmitted from an adjacent base station, wherein the adjacent cell terminal location information is location information corresponding to a terminal classified as a first terminal set or a second terminal set by the adjacent base station, or location information corresponding to a terminal classified as a first terminal set or a second terminal set by the adjacent base station and located at the edge beam position of the corresponding adjacent cell.

[0160] Based on location information of a terminal classified as a first terminal set or a second terminal set by a base station and location information of an adjacent cell terminal, at least one terminal device group to which subband-level frequency division scheduling is to be performed is determined, and the terminal device group includes at least one terminal classified as a first or second terminal set by a base station and at least one adjacent terminal classified as a first or second terminal set by an adjacent base station.

[0161] Herein, a specific method for determining at least one group of terminal devices to which subband-level frequency division scheduling is to be performed is as follows. Based on location information of terminals classified as a first terminal set or a second terminal set by a base station and location information of adjacent cell terminals, a fourth distance is calculated between each terminal classified as a first terminal set or a second terminal set by a base station and each terminal classified as a first terminal set or a second terminal set by an adjacent base station, or a fourth distance is calculated between each terminal located at the edge beam position of its own cell classified as a first terminal set or a second terminal set by a base station and each terminal located at the edge beam position of the corresponding adjacent cell classified as a first terminal set or a second terminal set by an adjacent base station. For any terminal classified as a first terminal set or a second terminal set by a base station, if the fourth distance between any adjacent terminal classified as a first terminal set or a second terminal set by an adjacent base station and the said terminal is less than the first predetermined distance threshold, the said terminal and the said adjacent terminal become members of a terminal device group, or for any terminal located at the edge beam position of its own cell classified as a first terminal set or a second terminal set by a base station, if the fourth distance between any adjacent terminal located at the edge beam position of the said adjacent cell classified as a first terminal set or a second terminal set by an adjacent base station and the said terminal is less than the first predetermined distance threshold, the said terminal and the said adjacent terminal become members of a terminal device group.

[0162] In cooperation with adjacent base stations, scheduling is performed for terminals included in a terminal device group through a subband-level frequency division scheduling method.

[0163] Furthermore, in the present application, when the designed frame structure method is used, an adaptive design for the SSB transmission method is required.

[0164] The first design method is a method of designing without changing the conventional 3GPP NR protocol.

[0165] All UEs in the idle state receive a CD-SSB (Cell-defining SSB, i.e., an SSB used to define a cell, which is the default SSB available for accessing the cell) at a preset SSB transmission timing before initiating initial random access.

[0166] After the UE initiates initial random access, for any UE scheduled to use the second TDD frame structure, the NCD-SSB (Non-cell-defining SSB, i.e., an SSB that cannot be used to define a cell) is monitored to complete the necessary RRM, RLM, and BFD measurements.

[0167] The base station performs the same frame header offset for the transmission of NCD-SSB. Here, the frame header offset value corresponding to NCD-SSB is the same as the frame header offset value corresponding to the second TDD frame structure, and each terminal in the second set of terminals receives NCD-SSB and completes the necessary wireless link measurement.

[0168] The period of NCD-SSB is set to be longer than the period of CD-SSB (this is in accordance with the provisions of the 3GPP NR protocol).

[0169] In addition, the reason NCD-SSB is referred to as an "SSB that cannot be used to define a cell" is that the MIB message within NCD-SSB does not contain information regarding SIB1 (specifically, the MIB message within NCD-SSB does not include CORESET#0 and Type 0-PDCCH CSS for the UE to receive / decode the SIB1 message).

[0170] The second design method is a method designed by modifying the conventional 3GPP NR protocol, and is specifically as follows.

[0171] In the design of the TDD frame structure in this application, the frame header offset value is the sum of the number of DL slots and the number of UL slots in the first TDD frame structure. If the "sum of the number of DL slots and the number of UL slots in the first TDD frame structure" is denoted by M, the designed modification is described as follows. The frame header of the first TDD frame structure is counted with the time starting point, and the satellite-based base station performs CD-SSB transmission in the first slot, the second slot, the M+1th slot, and the M+2th slot. FIG. 12 is a schematic diagram for determining the transmission slot of CD-SSB using the first frame structure group design method as an example, and M is equal to the number of GP slots N. Based on the example of a specific frame structure shown in FIG. 12 (frame period is 10ms, N=10), the designed modification for the SSB transmission method is as follows. In the case where the design is based on the SSB transmission method designated as case C of the 3GPP 5G protocol, according to the provisions of the 3GPP 5G protocol, CD-SSB is configured to perform transmission in the first four slots of every 20ms time length (i.e., every two wireless frames). Here, in accordance with the "base station performs scheduling for some UEs within the cell using the first TDD frame structure and the second TDD frame structure, respectively" proposed in this application, it can be modified so that CD-SSB performs transmission in the first two slots of every 20ms time length, the M+1th slot (11th slot), and the M+2th slot (12th slot).

[0172] Furthermore, the present application proposes optimizing the "time to first report GNSS measurement results." Specifically, it is as follows.

[0173] Based on the definition of the current version of the 3GPP protocol, after the initial random access is completed, the UE completes identity identification, authentication, and encryption by communicating with the core network via NAS messages, and then completes authentication of safe mode and query and reporting of GNSS measurement results via air interface interaction, followed by query and reporting of UE capabilities. In other words, a UE in an idle state can only report its GNSS measurement results (i.e., its own geographic location information) for the first time after the processing of the initial random access is completed (i.e., after the transmission of Msg5 is completed) and some other messages are transmitted.

[0174] In order to obtain a better interference avoidance effect through geographic isolation (in particular, through geographic isolation, the first random access message by the “UE initiating initial random access” avoids interference between UEs occurring with respect to the “UE after initiating initial random access”), in an exemplary embodiment, the terminal’s GNSS measurement result is included in the first message (i.e., Msg1 / MsgA) transmitted when the UE in the idle state performs initial random access (in other words, the “time of first reporting the GNSS measurement result” is advanced to the “time of first message transmission in the initial random access process)).

[0175] When the first message of the initial random access process is Msg1 (i.e., 4th stage random access is used as the initial random access), the method in which the GNSS measurement result is carried by Msg1 and transmitted to the base station along with the PRACH preamble sequence can be referenced from the "method in which PUSCH is carried by MsgA and transmitted to the base station along with the PRACH preamble sequence" of the 2nd stage random access. In other words, the GNSS measurement result is carried by Msg1 and transmitted to the base station along with the PRACH preamble sequence according to a pre-set time frequency resource (i.e., Grant Free Scheduling) that is broadcast among system messages.

[0176] If the first message of the initial random access process is MsgA (i.e., 2-stage random access was used in the initial random access), the GNSS measurement result is used as a new addition to part of PUSCH in MsgA.

[0177] FIG. 13 is a schematic diagram of an exemplary embodiment of a satellite communication method based on a time-division duplex (TDD) frame structure design according to the present application. The satellite communication method based on the time-division duplex (TDD) frame structure design used in a user terminal (UE) comprises the following steps.

[0178] In S1301, a first message corresponding to the terminal is transmitted to the base station.

[0179] Optionally, the first message may be a message that reports the location measurement result corresponding to the terminal for the first time after the terminal has completed initial random access.

[0180] Optionally, the first message may be the first message transmitted to the base station when the terminal initiates initial random access.

[0181] A user terminal (UE) transmits a first message corresponding to the terminal to a base station. In response, the base station receives the first message transmitted from the terminal and determines the set of terminals to which the terminal belongs based on a predetermined first criterion.

[0182] In S1302, scheduling for a terminal based on a first TDD frame structure or a second TDD frame structure is received from a base station, wherein the second TDD frame structure is generated by performing a frame header offset on the first TDD frame structure.

[0183] If the terminal belongs to the first set of terminals, it receives scheduling for the terminal based on the first TDD frame structure by the base station.

[0184] If the terminal belongs to the second set of terminals, it receives scheduling for the terminal based on the second TDD frame structure by the base station.

[0185] Here, the first set of terminals may be a set composed of terminals using the first TDD frame structure.

[0186] Here, the second set of terminals may be a set composed of terminals using the second TDD frame structure.

[0187] In an embodiment of the present application, based on classification and scheduling of UEs by a satellite-based base station within a cell, some terrestrial UEs use a first TTD frame structure, and the TDD frame structure of other terrestrial UEs uses a frame header offset version of the first TTD frame structure, i.e., a second TDD frame structure. In addition, all (or some) of the DL and UL slots in the second TDD frame structure correspond to the GP slots in the first TDD frame structure (i.e., occur at the same time), and naturally, all (or some) of the DL and UL slots in the first TDD frame structure correspond to the GP slots in the second TDD frame structure. Thus, when communication with some UEs enters a waiting period (i.e., the GP period of the corresponding frame structure), the satellite-based base station can communicate with other UEs, thereby improving the air interface resource utilization rate of the entire system.

[0188] Optionally, the first message is a message that first reports the location measurement result corresponding to the terminal after the terminal has completed initial random access, and the TDD frame structure configuration information carried by the first system message broadcast by the base station is configuration information corresponding to the first TDD frame structure, and if the terminal is not currently assigned to the first terminal set or the second terminal set after the first message among all messages transmitted by the terminal before transmitting the first message is received by the base station, the terminal is determined to belong to the first terminal set, provided that the reporting time of the message for first reporting the location measurement result corresponding to the terminal is after the terminal has completed initial random access, completed identity identification, authentication, and encryption with the core network by the Non-Access Layer (NAS), and completed the safe mode control process through air interface interaction with the base station.

[0189] Optionally, the first message is the first message transmitted to the base station when the terminal initiates initial random access, and the first report of the location measurement result corresponding to the terminal is transmitted to the base station together with the first message using a preset time frequency resource among system messages, and the TDD frame structure configuration information carried in the first system message broadcast by the base station is configuration information corresponding to the first TDD frame structure, and the terminal transmits the first message using the timing sequence of the first TDD frame structure.

[0190] In a method for determining whether to transmit a first message and a frame structure corresponding to the transmission of the first message when the first message is transmitted, wherein the first message is the first message transmitted to a base station when the terminal starts initial random access, the method comprises receiving a first system message broadcast by the base station, wherein the TDD frame structure setting information carried by the first system message broadcast by the base station is setting 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 location information of a terminal belonging to a second set of terminals among current beam positions covered by the beam transmitting the second system message, and location information of a terminal belonging to a second set of terminals whose distance from the boundary of the current beam position among each adjacent beam position is less than or equal to a first predetermined distance threshold, and based on the first system message broadcast by the base station, the second system message, the terminal's own location measurement result, and the first predetermined distance threshold, the same channel between terminals for terminals belonging to an adjacent second set of terminals as the terminal starts initial random access. The method includes the step of determining whether cross-link interference occurs, and if, as a result of the determination, it is determined that no inter-terminal interference occurs with respect to adjacent terminals in the second set of terminals, the terminal transmits the first message using the timing sequence of the first TDD frame structure; and if, as a result of the determination, it is determined that inter-terminal interference occurs with respect to at least one adjacent terminal in the second set of terminals, the terminal temporarily does not transmit the first message, and when the first message is transmitted, the first report of the location measurement result corresponding to the terminal is transmitted to the base station together with the first message using a preset time frequency resource among system messages.

[0191] In a method for determining whether to transmit a first message and a frame structure corresponding to the transmission of the first message when the first message is transmitted, wherein the first message is the first message transmitted to a base station when the terminal initiates initial random access, the method comprises receiving a first system message broadcast by a base station, wherein the TDD frame structure setting information carried by the first system message broadcast by the base station includes setting information corresponding to the first TDD frame structure and setting information for a frame header offset necessary to generate a second TDD frame structure, and receiving a second system message broadcast by a base station, wherein the second system message broadcast by the base station carries location information of a terminal belonging to a first set of terminals and a second set of terminals among current beam positions covered by a beam transmitting the second system message, and location information of a terminal belonging to a first set of terminals and a second set of terminals such that the distance closest to the boundary of the current beam position at each adjacent beam position is less than or equal to a first predetermined distance threshold, and wherein the terminal [is in relation to] the first system message broadcast by the base station, the second system message, the location measurement result of the terminal itself, and the first predetermined distance threshold Based on this, determining whether inter-terminal same-channel cross-link interference occurs for terminals belonging to an adjacent first terminal set or second terminal set as initial random access is initiated, and if, as a result of the determination, it is determined that no inter-terminal interference occurs for any adjacent terminal in either the first terminal set or the second terminal set, the terminal transmits a first message using a timing sequence of a first TDD frame structure or a second TDD frame structure, and if, as a result of the determination, it is determined that inter-terminal interference occurs for an adjacent terminal in the first terminal set but no inter-terminal interference occurs for an adjacent terminal in the second terminal set, the terminal transmits the first message using a timing sequence of a first TDD frame structure, and if, as a result of the determination, inter-terminal interference occurs for an adjacent terminal in the second terminal set but,If it is determined that no inter-terminal interference occurs with respect to adjacent terminals in the first set of terminals, the terminal transmits a first message using a timing sequence of a second TDD frame structure; and if it is determined as a result of the determination that inter-terminal interference occurs with respect to at least one adjacent terminal in the first set of terminals and at least one adjacent terminal in the second set of terminals, the terminal temporarily does not transmit the first message, and when the first message is transmitted, the first report of the location measurement result corresponding to the terminal includes the step of transmitting it to a base station together with the first message using a preset time frequency resource among system messages.

[0192] Furthermore, after avoiding possible inter-terminal co-channel cross-link interference by using a subband-level frequency division scheduling method between some terminals using different frame structures, if inter-terminal co-channel cross-link interference definitely occurs between said some terminals, interference cancellation is performed on the inter-terminal co-channel subband cross-link interference remaining on the terminal side where subband-level frequency division scheduling was performed, using one or more of a spatial domain interference cancellation method, an analog domain interference cancellation method, and a digital domain interference cancellation method.

[0193] FIG. 14 is a schematic diagram of the structure of a satellite communication device based on a time division duplex (TDD) frame structure design according to an embodiment of the present application.

[0194] As illustrated in FIG. 14, a satellite communication device (1400) based on the corresponding time division duplex (TDD) frame structure design is applied to a network device and includes a decision module (1401), a judgment module (1402), a first scheduling module (1403), and a second scheduling module (1404).

[0195] Here, the determination module (1401) is configured to determine a preset time division duplex (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 performing a frame header offset on the first TDD frame structure.

[0196] The judgment module (1402) is configured to determine the set of terminals to which the terminal belongs in response to receiving a first message transmitted from the terminal, wherein the set of terminals may be a first set of terminals or a second set of terminals.

[0197] The first scheduling module (1403) is configured to perform scheduling for a terminal based on the first TDD frame structure when the terminal belongs to the first set of terminals.

[0198] The second scheduling module (1404) is configured to perform scheduling on a terminal based on the second TDD frame structure when the terminal belongs to the second set of terminals.

[0199] FIG. 15 is a schematic diagram of the structure of a satellite communication device based on another time division duplex (TDD) frame structure design according to an embodiment of the present application.

[0200] As illustrated in FIG. 15, a satellite communication device (1500) based on the corresponding time division duplex (TDD) frame structure design is applied to a user terminal (UE) and includes a transmission module (1501) and a scheduling reception module (1502).

[0201] The transmission module (1501) is configured to transmit a first message corresponding to the terminal to the base station.

[0202] A scheduling receiving module (1502) is used in the module and is configured to receive scheduling for a terminal based on a first TDD frame structure or a second TDD frame structure from a base station, wherein the second TDD frame structure is generated by performing a frame header offset on the first TDD frame structure.

[0203] According to an embodiment of the present application, the present application further provides a communication device and a readable storage medium.

[0204] As illustrated in FIG. 16, the communication device includes one or more processors (1601), memory (1602), and an interface including a high-speed interface and a low-speed interface for connecting each component. Each component is connected to each other by different buses and may be mounted on a common main board or, if necessary, mounted via other methods. The processor processes instructions executed within the communication device and includes instructions stored in memory as such instructions, or instructions stored in memory to display graphic information of the GUI on an external input / output device (e.g., a display device coupled to the interface). In other embodiments, if necessary, multiple processors and / or multiple buses may be used together with multiple memories. Likewise, they may be connected to multiple communication devices, and each device may provide some necessary operations (e.g., functioning as a server array, a blade server group, or a multi-processor system). FIG. 16 illustrates a single processor (1601).

[0205] The memory (1602) is a non-transient computer-readable storage medium according to the present application. Here, instructions executable by at least one processor are stored in the memory so that a satellite communication method based on a time-division duplex (TDD) frame structure design according to the present application is executed by at least one processor. Computer instructions for executing a satellite communication method based on a time-division duplex (TDD) frame structure design according to the present application on a computer are stored in the non-transient computer-readable storage medium of the present application.

[0206] The memory (1602) is a non-transient computer-readable storage medium and can be used to store non-transient software programs, non-transient computer-executable programs and modules, for example, program instructions / modules corresponding to a satellite communication method based on a time-division duplex (TDD) frame structure design according to an embodiment of the present application. The processor (1601) performs various functional applications and data processing of the processor by executing the non-transient software programs, instructions and modules stored in the memory (1602), that is, implements a satellite communication method based on a time-division duplex (TDD) frame structure design according to the method embodiment.

[0207] The memory (1602) may include a program storage area for storing application programs required for at least one function of the operating system, and a data storage area for storing data generated in response to the use of the location measurement communication device. Additionally, the memory (1602) may include high-speed random access memory and may further include non-transient memory, such as, for example, at least one disk storage device, a flash storage device, or other non-transient solid-state storage device. Optionally, as the memory (1200), a memory remotely installed for the processor (1601) may be used. Such remote memory may be connected to the location measurement communication device via a network. Examples of the network may include, but are not limited to, the Internet, an enterprise intranet, a local area network, a mobile communication network, and combinations thereof.

[0208] 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) may be connected by a bus or other means. FIG. 16 illustrates a connection by a bus.

[0209] The input device (1603) can receive numeric or character information and also generate key signal inputs for user settings and function control of the positioning communication device, and may be an input device such as, for example, a touch screen, keypad, mouse, trackpad, touchpad, indicator stick, one or more mouse buttons, trackball, joystick, etc. The output device (1604) may include a display device, an auxiliary lighting device (e.g., LED), and a tactile feedback device (e.g., a vibration motor), etc. The display device may include, but is not limited to, a liquid crystal display (LCD), a light-emitting diode (LED) display, and a plasma display. In a plurality of embodiments, the display device may be a touch screen.

[0210] The systems and various embodiments described herein may be implemented by digital electronic circuit systems, integrated circuit systems, dedicated ASICs (Application-Specific Integrated Circuits), computer hardware, firmware, software, and / or combinations thereof. Each of these embodiments may be implemented by one or more computer programs. Such one or more computer programs may be executed and / or interpreted by a programmable system comprising at least one programmable processor. Such programmable processor may be a dedicated or general-purpose programmable processor and may receive data and instructions from a storage system, at least one input device, and at least one output device, and may also transmit data and instructions to said storage system, said at least one input device, and said at least one output device.

[0211] Such computer programs (which may be called programs, software, software applications, or code) include machine instructions for a programmable processor and may also be executed using a high-level processor and / or an object-oriented programming language and / or assembly / machine language. As used herein, the terms “machine-readable medium” and “computer-readable medium” refer to a machine-readable medium that receives machine instructions as machine-read signals, and is intended to provide machine instructions and / or data to any computer program product, device and / or device (e.g., magnetic disk, optical disk, programmable logic device (PLD)) of a programmable processor. The term “machine-read signal” refers to a machine-read signal that provides machine instructions and / or data to any signal of a programmable processor.

[0212] To provide interaction with a user, the systems and technologies described herein may be implemented on a computer. The computer may include a display device for displaying information to the user (e.g., a CRT (Cathode Ray Tube) or LCD (Liquid Crystal Display) monitor), a keyboard and a pointing device (e.g., a mouse or a trackball), and the user may provide input to the computer via the keyboard and the pointing device. Other types of devices may also be used to provide interaction with the user. For example, the feedback provided to the user may be sensor feedback of any form (e.g., visual feedback, auditory feedback, or tactile feedback), and input may also be received from the user in any form (audio input, voice input, or tactile input).

[0213] The systems and technologies described herein may be executed by a computing system including backend components (e.g., a system as a data server), a computing system including middleware components (e.g., an application server), a computing system including frontend components (e.g., a user computer including a graphical user interface or a Web browser, the user may interact with the systems described herein and the embodiments described herein through said graphical user interface or Web browser), or any combination of such backend components, middleware components, and frontends. Components of the systems may be connected to one another by communication of digital data in any format or medium (e.g., a communication network). Examples of communication networks include a Local Area Network (LAN), a Wide Area Network (WAN), and the Internet.

[0214] A computer system may include a user terminal and a server. The user terminal and the server are generally separated from each other and typically interact through a communication network. A relationship between the user terminal and the server is established by executing a computer program on a corresponding computer that has a user terminal-server relationship with each other.

[0215] Steps according to a new order may be executed, increased, or deleted by the various types of processors described above. For example, each step described in this application may be executed in parallel, sequentially, or according to different priorities. It should be understood that this application is not particularly limited thereto, as long as the expected results according to the technical design disclosed in this application can be realized.

Claims

Claim 1 A method comprising: a step of transmitting a first message to a base station through a user terminal (UE); and a step of receiving scheduling information transmitted from the base station through the user terminal (UE) based on a first TDD frame structure or a second TDD frame structure, wherein the second TDD frame structure is generated by performing a frame header offset on the first TDD frame structure. Claim 2 A method according to claim 1, wherein the first TDD frame structure comprises a plurality of protection section (GP) slots, a plurality of downlink (DL) slots, and a plurality of uplink (UL) slots, wherein the number of the plurality of protection section (GP) slots is equal to the sum of the plurality of downlink (DL) slots and the plurality of uplink (UL) slots, and wherein the plurality of downlink (DL) slots and the plurality of uplink (UL) slots in the second TDD frame structure correspond to the plurality of protection section (GP) slots in the first TDD frame structure. Claim 3 A method according to claim 1, wherein the first TDD frame structure comprises a plurality of protection section (GP) slots, a plurality of downlink (DL) slots, and a plurality of uplink (UL) slots, wherein the number of the plurality of protection section (GP) slots is greater than the sum of the plurality of downlink (DL) slots and the plurality of uplink (UL) slots, and wherein the plurality of downlink (DL) slots and the plurality of uplink (UL) slots in the second TDD frame structure correspond to a portion of the plurality of protection section (GP) slots in the first TDD frame structure. Claim 4 A method according to claim 1, wherein the first TDD frame structure comprises a plurality of protection section (GP) slots, a plurality of downlink (DL) slots, and a plurality of uplink (UL) slots, wherein the number of the plurality of protection section (GP) slots is less than the sum of the plurality of downlink (DL) slots and the plurality of uplink (UL) slots, and a portion of the plurality of downlink (DL) slots and the plurality of uplink (UL) slots in the second TDD frame structure corresponds to the plurality of protection section (GP) slots in the first TDD frame structure, and a collision slot exists between the first TDD frame structure and the second TDD frame structure. Claim 5 A method according to claim 1, wherein the first TDD frame structure comprises a plurality of protection section (GP) slots, a plurality of downlink (DL) slots, and a plurality of uplink (UL) slots, and the second TDD frame structure is generated by offsetting the frame header of the first TDD frame structure by a number of slots equal to the sum of the number of downlink (DL) slots and the number of uplink (UL) slots. Claim 6 The method according to claim 1 further comprises the steps of: the first message being a message that first reports a location measurement result corresponding to the user terminal (UE) terminal after the user terminal (UE) has completed initial random access; the method receiving a first system message broadcast by the base station through the user terminal (UE), wherein the first system message includes TDD frame structure setting information corresponding to the first TDD frame structure; the base station determining that the user terminal (UE) belongs to the first terminal set if, after the first message among all messages transmitted before the user terminal (UE) transmits the first message is received, the user terminal (UE) is not affiliated with the first terminal set or the second terminal set at the present time; and the reporting time of the first message being after the user terminal (UE) has completed initial random access, completed identity identification, authentication, and encryption with the core network through the non-access layer (NAS), and completed the safe mode control process through air interface interaction with the base station. Claim 7 In claim 1, the first message is the first message transmitted to the base station when the user terminal (UE) initiates initial random access, and the method further comprises the steps of: receiving a first system message broadcast by the base station through the user terminal (UE), wherein the first system message includes TDD frame structure setting information corresponding to the first TDD frame structure; transmitting a report of a location measurement result corresponding to the user terminal (UE) to the base station together with the first message using a preset time frequency resource among the system messages through the user terminal (UE); and transmitting the first message using the first TDD frame structure through the user terminal (UE). Claim 8 In claim 1, the first message is the first message transmitted to the base station when the user terminal (UE) initiates initial random access, and the transmission of the first message is based on a first system message and a second system message broadcast by the base station, the location measurement result of the user terminal (UE) itself, and a first predetermined distance threshold, determining whether inter-terminal cross-link interference occurs for terminals belonging to an adjacent second set of terminals as the initial random access is initiated; if, as a result of the determination, it is determined that inter-terminal interference does not occur for adjacent terminals within the second set of terminals, the first message is transmitted using the first TDD frame structure; if, as a result of the determination, it is determined that inter-terminal interference occurs for at least one adjacent terminal within the second set of terminals, the first message is not transmitted temporarily; and if, as a result of the determination, the first message is transmitted, the first report of the location measurement result corresponding to the user terminal (UE) is transmitted to the base station together with the first message using a preset time frequency resource among the system messages. A method comprising, wherein the base station broadcasts a first system message, and the first system message includes TDD frame structure setting information corresponding to the first TDD frame structure, and the base station broadcasts a second system message, and the second system message carries location information of a terminal belonging to a second set of terminals at a current beam position covered by a beam transmitting the second system message, and location information of a terminal belonging to a second set of terminals at each adjacent beam position such that the distance closest to the boundary of the current beam position is less than or equal to a first predetermined distance threshold. Claim 9 In claim 1, the first message is the first message transmitted to the base station when the user terminal (UE) initiates initial random access, and the transmission of the first message is based on a first system message and a second system message broadcast by the base station, the location measurement result of the user terminal (UE) itself, and a first predetermined distance threshold, determining whether inter-terminal cross-link interference occurs for terminals belonging to an adjacent first set of terminals or a second set of terminals as the initial random access is initiated; and as a result of the determination, if inter-terminal interference does not occur for adjacent terminals in either the first set of terminals or the second set of terminals, the first message is transmitted using a first TDD frame structure or a second TDD frame structure; and as a result of the determination, if it is determined that inter-terminal interference occurs for adjacent terminals in the first set of terminals but not for adjacent terminals in the second set of terminals, the first message is transmitted using a first TDD frame structure; and as a result of the determination, among the second set of terminals If it is determined that inter-terminal interference occurs with respect to adjacent terminals but no inter-terminal interference occurs with respect to adjacent terminals in the first set of terminals, the first message is transmitted using a second TDD frame structure; if, as a result of the determination, it is determined that inter-terminal interference occurs with respect to at least one adjacent terminal in the first set of terminals and at least one adjacent terminal in the second set of terminals, the first message is not transmitted temporarily; and if, as a result of the determination, the first message is transmitted, the first report of the location measurement result corresponding to the user terminal (UE) includes the step of transmitting to the base station together with the first message using a preset time frequency resource among system messages.A method characterized in that the base station broadcasts a first system message, and the first system message includes setting information for a TDD frame structure corresponding to the first TDD frame structure and setting information for a frame header offset necessary to generate the second TDD frame structure, and the base station broadcasts a second system message, and the second system message carries location information of a terminal belonging to a first set of terminals and a second set of terminals at a current beam position covered by a beam transmitting the second system message, and location information of a terminal belonging to a first set of terminals and a second set of terminals at each adjacent beam position such that the distance closest to the boundary of the current beam position is less than or equal to a first predetermined distance threshold. Claim 10 The method according to claim 1 further comprises the step of, after the base station avoids possible inter-terminal co-channel cross-link interference between some terminals using a subband-level frequency division scheduling method between some terminals using different frame structures, and when inter-terminal co-channel subband cross-link interference definitely occurs between said some terminals, performing interference cancellation on the inter-terminal co-channel subband cross-link interference remaining on the terminal side after the subband-level frequency division scheduling is performed, using one or more of a spatial domain interference cancellation method, an analog domain interference cancellation method, and a digital domain interference cancellation method. Claim 11 A user terminal (UE) comprising: one or more processors; and memory storing machine-readable instructions; wherein, when the one or more processors execute the machine-readable instructions alone or jointly, the user terminal (UE) performs any one of the methods of claims 1 through 10. Claim 12 A method comprising: determining a first TDD frame structure and a second TDD frame structure generated by performing a frame header offset on the first TDD frame structure; determining a set of terminals to which the user terminal (UE) belongs in response to receiving a first message transmitted from the user terminal (UE); performing scheduling for the user terminal (UE) based on the first TDD frame structure when the user terminal (UE) belongs to the first set of terminals; and performing scheduling for the user terminal (UE) based on the second TDD frame structure when the user terminal (UE) belongs to the second set of terminals. Claim 13 In claim 12, receiving adjacent cell terminal location information transmitted from an adjacent base station, wherein the adjacent cell terminal location information is location information corresponding to a user terminal (UE) classified as a first terminal set or a second terminal set by the adjacent base station, or location information corresponding to a user terminal (UE) classified as a first terminal set or a second terminal set by the adjacent base station and located at the edge beam position of the corresponding adjacent cell; and determining at least one terminal device group to which subband level frequency division scheduling is to be performed based on the location information of the user terminal (UE) classified as a first terminal set or a second terminal set by the base station and the adjacent cell terminal location information, wherein the terminal device group comprises at least one terminal classified as a first terminal set or a second terminal set by the base station and a first terminal set by the adjacent base station A method further comprising: a step of including at least one adjacent terminal classified as a second set of terminals; and a step of performing scheduling for a user terminal (UE) included in the terminal device group through a subband-level frequency division scheduling method in cooperation with the adjacent base station. Claim 14 In claim 13, the step of determining at least one terminal device group comprises: determining based on whether the location information of a user terminal (UE) classified as a first terminal set or a second terminal set by the base station is the adjacent cell terminal location information; calculating the distance between each terminal classified as a first terminal set or a second terminal set by the base station and each terminal classified as a first terminal set or a second terminal set by the adjacent base station, based on the location information of each terminal classified as a first terminal set or a second terminal set by the base station and the adjacent cell terminal location information; for any one terminal classified as a first terminal set or a second terminal set by the base station, if the calculated distance between the user terminal (UE) and the adjacent terminal is less than a first predetermined distance threshold, classifying the user terminal (UE) and the adjacent terminal classified as a second terminal set by the adjacent base station as members of the terminal device group; and the adjacent cell terminal location information classified as a first terminal set or a second terminal set by the base station A method characterized by comprising: a step of determining whether the location information is of a user terminal (UE) at the edge beam location of the corresponding adjacent cell; a step of calculating the distance between each terminal at the current cell edge beam location classified as a second terminal set by the base station and each terminal at the corresponding adjacent cell edge beam location classified as a first terminal set or a second terminal set by the adjacent base station, based on the location information of each terminal classified as a first terminal set or a second terminal set by the base station and the location information of the adjacent cell terminal; and a step of classifying the user terminal (UE) and the adjacent terminal at the edge beam location of the corresponding adjacent cell classified as a first terminal set or a second terminal set by the adjacent base station as members of a terminal device group, if the calculated distance between the user terminal (UE) and the adjacent terminal is less than a first distance threshold for any one terminal at the current cell edge beam location classified as a first terminal set or a second terminal set by the base station. Claim 15 In claim 12, the first TDD frame structure comprises a plurality of downlink (DL) slots and a plurality of uplink (UL) slots, and the method further comprises the step of performing transmission of CD-SSB in the first slot, the second slot, the M+1th slot, and the M+2nd slot when the sum of the number of the plurality of downlink (DL) slots and the plurality of uplink (UL) slots is denoted as M. Claim 16 In claim 12, the first message is the first message transmitted to the base station when the user terminal (UE) initiates initial random access, and the method further comprises: a step of broadcasting a first system message, wherein the first system message includes TDD frame structure setting information corresponding to the first TDD frame structure; a step of broadcasting a second system message, wherein the second system message carries location information of a terminal belonging to the second set of terminals at a current beam position covered by the beam transmitting the second system message, and location information of a terminal belonging to the second set of terminals at each adjacent beam position such that the distance closest to the boundary of the current beam position is less than or equal to a first predetermined distance threshold; and the user terminal (UE) determines whether, based on the first system message, the second system message, the location measurement result of the user terminal (UE) itself, and the first predetermined distance threshold, whether inter-terminal co-channel cross-link interference occurs for terminals belonging to the adjacent first set of terminals or second set of terminals as it initiates initial random access. A method characterized by determining, and as a result of the determination, if no inter-terminal interference occurs with respect to adjacent terminals of the second set of terminals, transmitting the first message using a first TDD frame structure; and as a result of the determination, if it is determined that inter-terminal interference occurs with respect to adjacent terminals of the second set of terminals, temporarily not transmitting the first message, and as a result of the determination, if the first message is transmitted, transmitting the first report of the location measurement result corresponding to the user terminal (UE) together with the first message using a preset time frequency resource among system messages. Claim 17 In claim 12, the first message is the first message transmitted to the base station when the user terminal (UE) initiates initial random access, and the method comprises: broadcasting a first system message, wherein the first system message includes setting information for a TDD frame structure corresponding to the first TDD frame structure and setting information for a frame header offset required to generate the second TDD frame structure; broadcasting a second system message, wherein the second system message carries location information of a terminal belonging to a first set of terminals and a second set of terminals at a current beam position covered by a beam transmitting the second system message, and location information of a terminal belonging to a first set of terminals and a second set of terminals at each adjacent beam position such that the distance closest to the boundary of the current beam position is less than or equal to a first predetermined distance threshold.The method further includes, and the user terminal (UE) determines whether inter-terminal co-channel cross-link interference occurs for terminals belonging to an adjacent first terminal set or second terminal set upon initiating an initial random access, based on the first system message, the second system message, the location measurement result of the user terminal (UE) itself, and a first predetermined distance threshold; and as a result of the determination, if inter-terminal interference does not occur for adjacent terminals of the first terminal set and the second terminal set, the first message is transmitted using a first TDD frame structure or a second TDD frame structure; and as a result of the determination, if it is determined that inter-terminal interference occurs for adjacent terminals in the first terminal set but not for adjacent terminals in the second terminal set, the first message is transmitted using the first TDD frame structure; and as a result of the determination, if it is determined that inter-terminal interference occurs for adjacent terminals in the second terminal set but not for adjacent terminals in the first terminal set A method characterized by transmitting the first message using a second TDD frame structure when determined, and, as a result of the determination, when it is determined that inter-terminal interference occurs between at least one adjacent terminal in the first set of terminals and at least one adjacent terminal in the second set of terminals, temporarily not transmitting the first message, and when the first message is transmitted, transmitting the first report of the location measurement result corresponding to the user terminal (UE) together with the first message to the base station using a preset time frequency resource among system messages. Claim 18 In claim 12, the step of determining the set of terminals to which the user terminal (UE) belongs is characterized by classifying the user terminal (UE) that does not belong to the first set of terminals and does not belong to the second set of terminals, without initiating initial random access to the base station that is in an idle state. Claim 19 In claim 12, the step of determining the set of terminals to which the above user terminal (UE) belongs comprises: a step of associating the terminal to the first set of terminals when, after a past terminal that accessed the base station and entered a connection state has entered an idle state, the base station discovers that the terminal is still in a beam position covered by the base station based on the location information of the ground beam position currently covered by itself and the location information stored on the base station side regarding the terminal; a step of, for a past terminal to which the base station belongs that has completed registration in the low-orbit satellite communication system and whose registration has not been released, the core network transmits the identifier of the terminal and the past location information to the satellite-based base station covering the terminal based on the past location information of the terminal stored therein, and the satellite-based base station covering the terminal assigns the terminal to the first set of terminals; and when the base station performs scheduling for a terminal that has started initial random access to itself, if it discovers that the terminal will be assigned to the second set of terminals based on the terminal set determination criteria, the terminal and the terminal assigned to the first set of terminals A method characterized by including the step of changing the terminal to belong to the first set of terminals when the distance between past terminals of each child state is greater than or equal to a first distance threshold. Claim 20 A method according to claim 12, characterized in that, before the user terminal (UE) initiates random access to any one of the satellite-based base stations from the satellite-ground cooperative network element, the user terminal receives a location measurement result transmitted to a wireless access node in the ground network and transmitted to the satellite-ground cooperative network element by the wireless access node. Claim 21 A base station comprising: one or more processors; and memory in which machine-readable instructions are stored; wherein, when the one or more processors execute the machine-readable instructions alone or jointly, the base station performs any one of the methods of claims 1 to 10.

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