Satellite communication method in time division duplex (TDD) mode, and wireless communication device

Abstract

Provided in the present disclosure is a satellite communication method in a TDD mode. The method comprises: a user equipment determining first information, wherein the first information includes at least one of the following: NSSS frame-structure pattern information and NPBCH frame-structure pattern information, the NSSS frame-structure pattern information is pattern information of an NSSS in the time division duplex (TDD) mode, the NPBCH frame-structure pattern information is pattern information of an NPBCH in the TDD mode, a first period of a first TDD frame structure in the TDD mode is a first value or a second value, and a configuration mode for the NPBCH frame-structure pattern information includes at least one of the following: an NPBCH original sequence repeatedly being transmitted between subframes and / or between radio frames, or the number of repetitions of the NPBCH original sequence being reduced on the basis of the bit value of the most significant bit (MSB) of a narrowband master information block (MIB-NB); and on the basis of the first information, the user equipment receiving a first signal transmitted by a base station, wherein the first signal is a downlink synchronization signal, and the first signal includes at least one of the following: the NSSS, the NPBCH, or an NPSS.

Description

A satellite communication method and wireless communication device in Time Division Duplex (TDD) mode Technical Field

[0001] This disclosure relates to the field of wireless communication, and in particular to a satellite communication method and wireless communication device in time division duplex (TDD) mode. Background Technology

[0002] To apply NB-IoT to satellite communication systems, energy consumption must be considered. Solar panels on satellites are designed to convert solar energy into electricity, and the satellite needs to carry batteries to store the energy converted during sunlight exposure. However, the size of the solar panels (and batteries) is limited by the satellite's surface area. LEO satellites have smaller solar panels due to their compact design. GEO satellites have larger panels and convert more power compared to LEO satellites. Medium Earth Orbit (MEO) satellites can accommodate slightly larger panels, but they still face limitations. Furthermore, due to orbital dynamics, LEO / MEO satellites have significantly different levels of solar exposure. A LEO satellite takes 90-120 minutes to orbit the Earth, spending more than half of that time in the Earth's shadow, meaning it will not receive sunlight during this period. To improve satellite lifespan, network energy-saving strategies are needed to reduce satellite power consumption. In addition, several other unresolved issues exist in satellite communication. Therefore, a time-division duplex (TDD) satellite communication method and wireless communication equipment are needed to improve existing technologies. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a satellite communication method in time division duplex (TDD) mode, which addresses the above-mentioned deficiencies of the prior art and aims to solve the problems existing in the prior art.

[0004] According to one aspect of this disclosure, a satellite communication method in time division duplex (TDD) mode is provided, executed on a user equipment, comprising:

[0005] The first information is determined; wherein the first information includes at least one of the following: narrowband secondary synchronization signal (NSSS) frame structure pattern information and narrowband physical broadcast channel (NPBCH) frame structure pattern information; wherein the NSSS frame structure pattern information is the pattern information of NSSS in time division duplex (TDD) mode, the NPBCH frame structure pattern information is the pattern information of NPBCH in TDD mode, the first period of the first TDD frame structure in TDD mode is a first value or a second value, and the configuration method of the NPBCH frame structure pattern information includes at least one of the following: the original NPBCH sequence is repeatedly transmitted between subframes and / or between radio frames, or the number of repetitions of the original NPBCH sequence is reduced based on the bit value of the most significant bit (MSB) in the narrowband main information block (MIB-NB);

[0006] Based on the first information, a first signal is received, wherein the first signal is a downlink synchronization signal, and the first signal includes at least one of the following: the NSSS, the NPBCH, or the narrowband primary synchronization signal NPSS.

[0007] According to one aspect of this disclosure, a satellite communication method in time division duplex (TDD) mode is provided, executed at a base station, comprising:

[0008] The first information is determined; wherein the first information includes at least one of the following: narrowband secondary synchronization signal (NSSS) frame structure pattern information and narrowband physical broadcast channel (NPBCH) frame structure pattern information; wherein the NSSS frame structure pattern information is the pattern information of NSSS in time division duplex (TDD) mode, the NPBCH frame structure pattern information is the pattern information of NPBCH in TDD mode, the first period of the first TDD frame structure in TDD mode is a first value or a second value, and the configuration method of the NPBCH frame structure pattern information includes at least one of the following: the original NPBCH sequence is repeatedly transmitted between subframes and / or between radio frames, or the number of repetitions of the original NPBCH sequence is reduced based on the bit value of the most significant bit (MSB) in the narrowband main information block (MIB-NB);

[0009] Based on the first information, a first signal is sent, wherein the first signal is a downlink synchronization signal, and the first signal includes at least one of the following: the NSSS, the NPBCH, or the narrowband primary synchronization signal NPSS.

[0010] According to one aspect of this disclosure, a wireless communication device is provided, including a processor and a memory for storing a computer program, the processor for calling and running the computer program stored in the memory to perform steps in the data processing method as described in any of the preceding claims.

[0011] According to one aspect of this disclosure, a readable storage medium is provided for storing a computer program that is invoked and executed by a processor to perform any of the methods described above. Attached Figure Description

[0012] To more clearly illustrate the embodiments of this disclosure or related technologies, the following figures will be briefly described in the embodiments. Obviously, the figures are merely some embodiments of this disclosure, and those skilled in the art can obtain other figures based on these figures without creative effort.

[0013] Figure 1 illustrates a schematic diagram of the wireless communication system architecture provided in this disclosure.

[0014] Figure 2 illustrates one of the schematic diagrams of a satellite communication method in Time Division Duplex (TDD) mode provided in this disclosure.

[0015] Figures 3-20 illustrate the NSSS frame structure pattern information provided in this disclosure.

[0016] Figures 21-32 illustrate the NPBCH frame structure pattern information provided in this disclosure.

[0017] Figure 33 illustrates the second schematic diagram of the satellite communication method in Time Division Duplex (TDD) mode provided in this disclosure.

[0018] Figure 34 illustrates a schematic diagram of the activated uplink and downlink frame structure provided in this disclosure.

[0019] Figure 35 illustrates a schematic diagram of the RAR window design provided in this disclosure.

[0020] Figure 36 illustrates a schematic diagram of the NPRACH transmission rules provided in this disclosure.

[0021] Figure 37 illustrates an exemplary block diagram of a wireless communication system provided in this disclosure. Detailed Implementation

[0022] The embodiments of this disclosure have been described in detail with reference to the accompanying drawings, outlining technical aspects, structural features, objectives, and effects, as described below. Specifically, the terminology used in the embodiments of this disclosure is for the purpose of describing particular embodiments only and is not intended to limit the disclosure.

[0023] In this disclosure, “A or B” may mean “A only”, “B only”, or “both A and B”.

[0024] In other words, in this disclosure, “A or B” can be interpreted as “A and / or B”. For example, in this disclosure, “A, B or C” can mean “A only”, “B only”, “C only” or “any combination of A, B, and C”.

[0025] The forward slash ( / ) or comma used in this disclosure can mean "and / or". For example, "A / B" can mean "A and / or B". Therefore, "A / B" can mean "A only", "B only", or "both A and B". For example, "A, B, C" can mean "A, B, or C".

[0026] In this disclosure, "at least one of A and B" may mean "only A", "only B" or "both A and B". Furthermore, in this disclosure, the expression "at least one of A or B" or "at least one of A and / or B" may be interpreted as "at least one of A and B".

[0027] Additionally, in this disclosure, "at least one of A, B, and C" may mean "A only", "B only", "C only" or "any combination of A, B, and C". Furthermore, "at least one of A, B, or C" or "at least one of A, B, and / or C" may mean "at least one of A, B, and C".

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0029] Those skilled in the art will recognize and understand that the details of the described examples are merely illustrative of some embodiments, and that the teachings set forth herein are applicable to various alternative settings.

[0030] The technical solutions disclosed herein can be applied to various wireless communication systems, such as: Long Term Evolution (LTE) systems, LTE Frequency Division Duplex (FDD) systems, LTE Time Division Duplex (TDD) systems, 5G communication systems, or future wireless communication systems, etc.

[0031] For example, the wireless communication system 100 of this disclosure is shown in FIG1. ​​The wireless communication system 100 may include a base station 110, which may be a device communicating with user equipment (UE) 120. The base station 110 can provide communication coverage for a specific geographical area and can communicate with user equipment located within that coverage area. Optionally, the base station 110 may be an evolved Node B (eNB or eNodeB) in an LTE system, or it may be a mobile switching center, relay station, access point, vehicle-mounted equipment, wearable device, hub, switch, bridge, router, network-side equipment in a 5G network, or a base station in a future communication system, etc.

[0032] The wireless communication system 100 also includes at least one user equipment 120 located within the coverage area of ​​the base station 110. "User equipment" as used herein includes, but is not limited to, devices configured to receive / transmit communication signals via wired connections, such as via Public Switched Telephone Networks (PSTN), Digital Subscriber Line (DSL), digital cable, direct cable connection; and / or another data connection / network; and / or via a wireless interface, such as for cellular networks, Wireless Local Area Networks (WLAN), digital television networks such as DVB-H networks, satellite networks, AM-FM broadcast transmitters; and / or other user equipment. User equipment configured to communicate via a wireless interface may be referred to as a "wireless communication terminal," "wireless terminal," or "mobile terminal." Examples of mobile terminals include, but are not limited to, satellite or cellular phones; personal communications system (PCS) terminals that can combine cellular radiotelephone with data processing, fax, and data communication capabilities; PDAs that may include radiotelephones, pagers, Internet / intranet access, web browsers, notebooks, calendars, and / or Global Positioning System (GPS) receivers; and conventional laptop and / or handheld receivers or other electronic devices that include radiotelephone transceivers. User equipment can refer to access terminals, user units, user stations, mobile stations, mobile stations, remote stations, remote user equipment, mobile devices, wireless communication equipment, or user agents. Access terminals can be cellular phones, cordless phones, Session Initiation Protocol (SIP) phones, Wireless Local Loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, in-vehicle equipment, wearable devices, user equipment in 5G networks, or user equipment in future PLMN evolutions, etc.

[0033] Optionally, user equipment 120 can perform device-to-device (D2D) communication with each other.

[0034] Alternatively, 5G communication systems or 5G networks may also be referred to as New Radio (NR) systems or NR networks.

[0035] The wireless communication system 100 also includes a core network 130. The core network 130 may be an IP mobile communication network operated by a mobile communication operator. For example, the core network 130 may be the core network used by the mobile communication operator that operates and manages the wireless communication system 100, or it may be the core network used by a virtual mobile communication operator such as an MVNO (Mobile Virtual Network Operator).

[0036] The core network 130 can connect to the base station 110, serving as a relay device for transmitting user data. User equipment 120 transmits and receives user data via the core network 130. It should be noted that user data communication is not limited to IP communication; it can also be non-IP communication.

[0037] Figure 1 illustrates an exemplary base station 110, two user equipment 120, and a core network 130. Optionally, the wireless communication system 100 may include multiple base stations, and each base station may include other numbers of user equipment within its coverage area. This disclosure does not limit this.

[0038] Optionally, the wireless communication system 100 may also include other network entities such as a network controller, a mobility management entity, and network elements, and this disclosure does not limit this. For example, the core network 130 may include other network entities such as a network controller, a mobility management entity, and network elements, and this disclosure does not limit this.

[0039] It should be understood that devices with wireless communication capabilities in the network / system described in this disclosure may be referred to as wireless communication devices. Taking the wireless communication system 100 shown in Figure 1 as an example, the wireless communication devices may include a base station 110, a user equipment 120, and a core network 130 with communication capabilities. The base station 110 and the user equipment 120 may be the specific devices described above, which will not be repeated here. The wireless communication devices may also include other devices in the wireless communication system 100 (core network 130). For example, the core network 130 may include other network entities such as network controllers and mobility management entities, which are not limited in this disclosure.

[0040] The information sending method provided in this application will be described in detail below with reference to the accompanying drawings and through some embodiments and application scenarios.

[0041] Based on the current state of technology, a certain number of radio frames are activated for downlink transmission within every N radio frames. If the activated radio frames do not contain NSSS, it will directly affect downlink synchronization. Furthermore, transmitting a complete NPBCH will consume a significant amount of access time. Therefore, this disclosure proposes a satellite communication method in Time Division Duplex (TDD) mode to address these issues.

[0042] Figure 2 illustrates one of the flowcharts of a satellite communication method in Time Division Duplex (TDD) mode provided in this disclosure. As shown in Figure 2, this method can be applied to a user equipment (UE120). The satellite communication method includes:

[0043] Step S100, UE120 determines the first information; wherein, the first information includes at least one of the following: narrowband secondary synchronization signal NSSS frame structure pattern information, narrowband physical broadcast channel NPBCH frame structure pattern information; wherein, the NSSS frame structure pattern information is the pattern information of NSSS in time division duplex (TDD) mode, the NPBCH frame structure pattern information is the pattern information of NPBCH in TDD mode, the first period of the first TDD frame structure in TDD mode is a first value or a second value, and the configuration method of the NPBCH frame structure pattern information includes at least one of the following: the original NPBCH sequence is repeatedly transmitted between subframes and / or between radio frames, or the number of repetitions of the original NPBCH sequence is reduced based on the bit value of the most significant bit (MSB) in the narrowband main information block (MIB-NB);

[0044] In step S200, UE120 receives a first signal sent by base station 110 based on the first information. The first signal is a downlink synchronization signal, which includes at least one of the following: the NSSS, the NPBCH, or the narrowband primary synchronization signal NPSS.

[0045] Specifically, the UE120 can predefine first information. Since the first information includes the frame structure pattern information of the Narrowband Secondary Synchronization Signal (NSSS) and / or the frame structure pattern information of the Narrowband Physical Broadcast Channel (NPBCH), the UE120 can correctly receive at least one downlink synchronization signal from the base station 110, including the NSSS, the NPBCH, or the Narrowband Primary Synchronization Signal (NPSS), based on the determined NSSS frame structure pattern information and / or NPBCH frame structure pattern information, so as to achieve synchronization with the base station 110. More specifically, the UE120 receives the NPSS signal for time-frequency synchronization, receives the NSSS signal for frame synchronization and obtains the cell PCID. After receiving the NPBCH message, the UE120 can obtain the system's frame information and the scheduling information of the SIB1-NB. It is worth noting that base station 110 can also predefine the first information; the first TDD frame structure in Time Division Duplexing (TDD) mode is the traditional (legacy) TDD frame structure. As an example, the first value is 90ms, and the second value is 80ms. Furthermore, the NPBCH frame structure pattern information is configured in at least one of the following ways: the original NPBCH sequence is repeatedly transmitted between subframes and / or between radio frames, or the number of repetitions of the original NPBCH sequence is reduced based on the bit value of the most significant bit (MSB) in the narrowband master information block MIB-NB, which can reduce the downlink synchronization delay.

[0046] In embodiments of this disclosure, the original NSSS sequence in the NSSS frame structure pattern information is repeatedly transmitted between subframes.

[0047] It is worth noting that the original NSSS sequence can be repeated between multiple subframes within a single radio frame, or between multiple subframes across multiple radio frames.

[0048] In embodiments of this disclosure, a period of the first TDD frame structure in step S100 contains M or N radio frames, and a period of the first TDD frame structure contains only one radio frame for downlink transmission.

[0049] Specifically, M is 9 for example, and N is 8 for example. That is to say, the first TDD frame structure has two periods: one period is 90ms, in which the first TDD frame structure contains 9 radio frames, only one of which is used for downlink transmission; the other period is 80ms, in which the first TDD frame structure contains 8 radio frames, only one of which is used for downlink transmission.

[0050] For example, when M is 9, the period of the first TDD frame structure is 90ms. That is, the first TDD frame structure contains 9 radio frames, each with a duration of 10ms. Within one period of each TDD frame structure, only one 10ms radio frame is used for downlink transmission. In this case, the configuration method of the NSSS frame structure pattern information includes at least one of the following:

[0051] Pattern 1: Four different NSSS sequences are sequentially mapped between radio frames used for downlink transmission, and one NSSS sequence is mapped in a preset subframe position of each radio frame used for downlink transmission.

[0052] Specifically, the four different NSSS sequences are obtained by applying four different cyclic shift values ​​to the original NSSS sequences. These four different NSSS sequences can include NSSS sequence 1, NSSS sequence 2, NSSS sequence 3, and NSSS sequence 4. During the mapping process, if only one NSSS sequence is mapped at a time, then one of NSSS sequence 1, NSSS sequence 2, NSSS sequence 3, or NSSS sequence 4 is mapped each time, and the mapping is performed cyclically in the order of NSSS sequence 1, NSSS sequence 2, NSSS sequence 3, and NSSS sequence 4. If two different NSSS sequences are mapped each time, then NSSS sequence 1 and NSSS sequence 2 are mapped first, followed by NSSS sequence 3 and NSSS sequence 4, and so on. If four different NSSS sequences are mapped each time, then NSSS sequence 1, NSSS sequence 2, NSSS sequence 3, and NSSS sequence 4 are mapped each time, and so on. Further details will not be elaborated upon here. Additionally, the preset subframe position can be subframe #6, subframe #7, or subframe #9.

[0053] For example, for pattern 1, there are two configuration options:

[0054] Configuration Method 1: As shown in Figure 3, four different NSSS sequences are cyclically mapped at position #6 or #7 of subframes in each radio frame used for downlink transmission. The original NSSS sequences transmitted on the radio frame are the same within a 90ms period, and are cyclically shifted once in the next 90ms period, and so on, for a total of 4 cyclic shifts. Thus, the period of the entire NSSS sequence is extended to 90*4ms, and the cyclic shift values ​​of the four NSSS sequences are different within this period. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0055] Where, θ f Represents a circular shift term, n f This indicates the frame number. By configuring it as described above, downlink synchronization latency can be reduced.

[0056] Configuration Method 2: Four different NSSS sequences are cyclically mapped at position #9 of subframes in each radio frame used for downlink transmission. The original NSSS sequences transmitted on radio frames are the same within a 90ms period. They are cyclically shifted once in the next 90ms period, and so on, for a total of four cyclic shifts. This extends the period of the entire NSSS sequence to 90*4, and the cyclic shift values ​​of the four NSSS sequences within this period are different. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift values. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0057] Where, θ f Represents a circular shift term, n f Indicates the frame number.

[0058] Pattern 2: Maps two different NSSS sequences in each radio frame used for downlink transmission.

[0059] It is worth noting that the two different NSSS sequences are obtained by applying two different cyclic shifts to the original NSSS sequence. Specifically, as shown in Figure 4, in order to ensure that NSSS can be detected in the radio frames used for downlink transmission within each 90ms period, and to shorten the NSSS transmission period compared to Pattern 1, two different NSSS sequences (e.g., NSSS sequence 1 and NSSS sequence 2) are mapped to two preset subframe positions (available subframe positions) on a radio frame used for downlink transmission in one TDD period. In the next TDD period, two preset subframe positions (available subframe positions) on a radio frame used for downlink transmission are mapped to two NSSS sequences (e.g., NSSS sequence 3 and NSSS sequence 4). The period of the entire NSSS sequence is extended to 90*4ms. For example, the two preset subframe positions are #8 and #9. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0060] Where, θ f Represents a circular shift term, n f Indicates the wireless frame number, n p This indicates the subframe number, with values ​​of 8 and 9. The above settings can further reduce synchronization time and improve timing accuracy.

[0061] Pattern 3: Four different NSSS sequences are mapped in each radio frame used for downlink transmission, and four different NSSS sequences are mapped at four preset subframe positions in each radio frame used for downlink transmission.

[0062] Specifically, as shown in Figure 5, to ensure that NSSS can be detected within each 90ms period of the radio frame used for downlink transmission and to shorten the NSSS transmission period, four different NSSS sequences are cyclically mapped at four preset subframe positions (available subframe positions) of each radio frame used for downlink transmission. In other words, four identical original NSSS sequences are mapped at the four preset subframe positions (available subframe positions) of each radio frame used for downlink transmission, and different cyclic shift values ​​are applied to the four identical original NSSS sequences. Thus, the NSSS period is 90*1. For example, four NSSS sequences are mapped at subframes #6, #7, #8, and #9 of each radio frame used for downlink transmission. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0063] Where θ f Represents a circular shift term, n p This indicates the subframe number, with values ​​ranging from 6 to 9.

[0064] In the embodiments of this disclosure, the first information in step S100 further includes a second TDD frame structure in TDD mode, wherein the second period of the second TDD frame structure is a first value, the second period is the time interval between the start subframes of two activated downlink transmissions, the activated downlink transmission includes N subframes, and the configuration method for activating downlink transmission includes:

[0065] Taking two consecutive radio frames in the preset first TDD frame structure as a reference, the subframe K position of the first radio frame in the two consecutive radio frames is taken as the starting subframe of the radio frame used for downlink transmission.

[0066] The subframe L position of the second radio frame in two consecutive radio frames is used as the terminating subframe of the radio frame used for downlink transmission.

[0067] Specifically, the second TDD frame structure in TDD mode is a frame structure different from the traditional TDD frame structure. The second TDD frame structure includes activating downlink transmission across two radio frames, starting from a designated subframe of a radio frame in the traditional TDD frame structure. The length of the activated subframe for downlink transmission is 8. For example, the first value can be 90ms. That is, as an example, the second period of the second TDD frame structure can be 90ms, meaning that the interval between the starting subframes of two activated radio frames for downlink transmission is 90ms. For example, the value of K can be at least one of the following: 3, 4, 8, and / or 9; the value of L can be at least one of the following: 0, 1, 5, and / or 6. That is, the position of the activated subframe for downlink transmission can be at least one of the following: [34567890] or [45678901] or [89012345] or [90123456].

[0068] Taking the second TDD frame structure as an example, as shown in Figure 6, the subframe structure in the upper row of Figure 6 is the legacy subframe structure, and the subframe structure in the upper row of Figure 6 is the subframe structure to be used in this embodiment. K is 4 and L is 1. In the second TDD frame structure, 8 subframes for downlink transmission are activated. The SIB-NB at position #4 of the radio frame becomes the first subframe to activate downlink, the NPSS mapped at position #5 becomes the second subframe to activate downlink, the NSSS mapped at position #9 becomes the sixth subframe to activate downlink, and the NPBCH mapped at position #0 of the next radio frame becomes the seventh subframe to activate downlink. The NPBCH period is extended to 640ms*9. In the prior art, the period of the original NSSS sequence is 20ms, and only in even-numbered frames, 4 NSSS sequences are generated by cyclic shifting every 80ms. In this disclosure, in order to ensure that the NSSS sequence can be detected in each downlink frame activated in a 90ms period, the configuration method of the NSSS frame structure pattern information adopts at least one of the following patterns:

[0069] Pattern 1: Four different NSSS sequences are sequentially mapped between each active downlink transmission used for downlink transmission, and an NSSS sequence is mapped at a preset subframe position of each active downlink transmission used for downlink transmission.

[0070] Specifically, NSSS sequences are mapped at one preset subframe position (available subframe position) on each active downlink transmission used for downlink transmission. The original NSSS sequences transmitted on the active downlink transmission are the same within a 90ms period, with a cyclic shift value applied once. A different cyclic shift value is applied in the next 90ms period. That is, four different NSSS sequences are cyclically mapped sequentially in each active downlink transmission used for downlink transmission. Thus, the entire NSSS period is extended to 90*4, with different cyclic shift values ​​for the four NSSS sequences within each NSSS period. For example, the original NSSS sequence is mapped at position #6, #7, #8, or #9 of each active downlink transmission used for downlink transmission, with different cyclic shift values ​​applied to each position. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0071] Where, θ f Represents a circular shift term, n f This indicates the frame number. The benefit of this is that it reduces downlink synchronization latency.

[0072] Pattern 2: Maps two different NSSS sequences in each active downlink transmission used for downlink transmission.

[0073] Specifically, in each active downlink transmission used for downlink transmission, two NSSS raw sequences are mapped to two preset subframe positions (available subframe positions). The two NSSS raw sequences apply different cyclic shift values. The entire NSSS period is extended to 90*2ms. Within the NSSS period, four identical NSSS raw sequences apply different cyclic shift values. For example, the two preset subframe positions can be subframes #8 and #9. Thus, two NSSS sequences can be mapped to subframes #8 and #9 in each active downlink transmission used for downlink transmission. The generation of the NSSS sequence is related to the NSSS raw sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0074] Where, θ f Represents a circular shift term, n f Indicates the wireless frame number, n p This indicates the subframe number, with values ​​of 8 and 9. The benefit of this is that it further reduces synchronization time and improves timing accuracy.

[0075] It is worth noting that, in the second frame structure, the configuration method of the NSSS frame structure pattern information also adopts the following pattern: four different NSSS sequences are mapped in each active downlink transmission used for downlink transmission, and four different NSSS sequences are mapped at the four preset subframe positions of each active downlink transmission used for downlink transmission. The specific pattern configuration method can be modified according to other embodiments of this disclosure, and is not limited here.

[0076] In embodiments of this disclosure, a period of the first TDD frame structure includes M, and a period of the first TDD frame structure includes only two radio frames for downlink transmission, the two radio frames for downlink transmission including a first radio frame for downlink transmission and a second radio frame for downlink transmission.

[0077] Specifically, as stated above, the first TDD frame structure is a traditional TDD frame structure, and M can be 9. That is, one period of the first TDD frame structure is 90ms, and 90ms contains 9 radio frames. The 9 radio frames include two radio frames used for downlink transmission. The configuration method of the NSSS frame structure pattern information includes at least one of the following:

[0078] Pattern 1: Four different NSSS sequences are sequentially mapped during each first TDD cycle, and an NSSS sequence is mapped in a preset subframe position in the first or second radio frame used for downlink transmission, wherein the first TDD cycle is the first cycle of the first TDD frame structure.

[0079] For example, as shown in Figure 7, two consecutive radio frames used for downlink transmission in each first TDD cycle are used for downlink transmission. The original NSSS sequences transmitted at a preset subframe position in the first or second radio frame (even-numbered frame position) used for downlink transmission within a 90ms cycle are identical. A cyclic shift value is applied, and another cyclic shift value is applied in the next 90ms cycle, and so on. The entire NSSS cycle is extended to have four different cyclic shifts for the original NSSS sequences within a 90*4ms cycle. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0080] Where θ f Represents a circular shift term, n f Indicates the frame number.

[0081] Pattern 2: Four different NSSS sequences are sequentially mapped between each radio frame used for downlink transmission.

[0082] For example, as shown in Figure 8, to reduce the timing period of the NSSS frame, two original NSSS sequences are mapped to preset subframe positions (available subframe positions) in each radio frame used for downlink transmission. The two original NSSS sequences are applied with different cyclic shift values ​​(e.g., NSSS sequence 1 and NSSS sequence 2, or NSSS sequence 3 and NSSS sequence 4). This shortens the timing period of the NSSS frame to 90ms*2. For example, the NSSS sequence is mapped to position #9 of subframe in each radio frame used for downlink transmission in each TDD frame structure. Thus, two radio frames used for downlink transmission transmit two different NSSS sequences. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on at least one of the following formulas:

[0083] Case 1: If two radio frames for downlink transmission are transmitted starting from an odd-numbered offset frame within the period, the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0084] Where, θf Represents a circular shift term, n f Indicates the frame number.

[0085] Case 2: If two radio frames for downlink transmission are transmitted starting from an even-numbered offset frame within the period, the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0086] Where, θ f Represents a circular shift term, n f Indicates the frame number.

[0087] Pattern 3: Two different NSSS sequences are mapped in each radio frame used for downlink transmission, and different NSSS sequences are mapped at two preset subframe positions in the first radio frame and at two preset subframe positions in the second radio frame.

[0088] For example, as shown in Figure 9, four different NSSS sequences are generated through cyclic shifting. In TDD mode, the NSS period is extended to 90ms*4. To reduce the NSSS frame timing period, four identical original NSSS sequences are mapped to four available subframe positions in two radio frames, applying different cyclic shift values. This shortens the NSSS frame timing period to 90ms. For example, four different NSSS sequences can be mapped to subframes #8 and #9 in the two radio frames of the first TDD frame period. For instance, NSSS sequence 1 and NSSS sequence 2 can be mapped in the first radio frame, and NSSS sequence 3 and NSSS sequence 4 can be mapped in the second radio frame. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on at least one of the following formulas:

[0089] Case 1: If two radio frames are transmitted starting from an odd-numbered offset frame within the period, then the formula is:

[0090] Where θ f Represents a circular shift term, n f Indicates the frame number, n p Indicates the subframe number.

[0091] Case 2: If two radio frames are transmitted starting from an even-numbered offset frame within the period, then the formula is:

[0092] Where θ f Represents a circular shift term, nf Indicates the frame number, n p Indicates the subframe number.

[0093] Pattern 4: Two different NSSS sequences are mapped in each first TDD cycle, and different NSSS sequences are mapped in two preset subframe positions of the first or second radio frame used for downlink transmission.

[0094] For example, as shown in Figure 10, four different NSSS sequences are generated through cyclic shifting. In TDD mode, the NSSS period is extended to 90ms*4. To reduce the NSSS frame timing period, subframes #8 and #9 of the first or second radio frame (i.e., even-numbered radio frames) used for downlink transmission map the two original NSSS sequences and apply different cyclic shift values. Therefore, the NSSS frame timing period is shortened to 90ms*2. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0095] Where θ f Represents a circular shift term, n f Indicates the frame number, n p Indicates the subframe number.

[0096] Pattern 5: Four different NSSS sequences are mapped in each first TDD cycle; different NSSS sequences are mapped in four preset subframe positions in each of the first or second radio frames.

[0097] For example, as shown in Figure 11, subframes #6, #7, 8, and #9 of the even-numbered radio frames activated in each first TDD cycle map to the same four original NSSS sequences, applying different cyclic shift values. Therefore, the timing period of the NSSS frames is shortened to 90ms*1. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0098] Where, θ f Represents a circular shift term, n f Indicates the frame number, n p Indicates the subframe number.

[0099] In the embodiments of this disclosure, the first period of the first TDD frame structure is a first value, one period of the first TDD frame structure contains M radio frames, and one period of the first TDD frame structure contains only three radio frames for downlink transmission.

[0100] Specifically, as stated above, the first TDD frame structure is a traditional TDD frame structure, where M can be 9. This means that one period of the first TDD frame structure is 90ms, and the 90ms period contains 9 radio frames, three of which are used for downlink transmission. The configuration method of the NSSS frame structure pattern information includes at least one of the following:

[0101] Pattern 1: Four different NSSS sequences are mapped in three first TDD cycles; four different NSSS sequences are sequentially mapped in a cyclic manner between each even-numbered radio frame, wherein the even-numbered radio frame is the radio frame used for downlink transmission located at an even position in the first TDD frame structure, and only one available subframe in each even-numbered radio frame is used to map the NSSS sequence.

[0102] For example, three consecutive radio frames within a 90ms period are used for downlink transmission. The NSSS transmitted on subframe #9 of even-numbered radio frames within a 90ms period is the same, but different cyclic shifts are applied. It is worth noting that the even-numbered radio frames here are included in the three consecutive radio frames used for downlink transmission within a 90ms period, thus extending the entire NSSS period to 90*3. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on at least one of the following formulas:

[0103] Case 1: When transmitting three consecutive radio frames starting from an odd-numbered frame, two radio frames in the first 90ms are mapped to the NSSS sequence, one radio frame in the second 90ms is mapped to the NSSS sequence, and two radio frames in the third radio frame are mapped to the NSSS sequence. The cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0104] Where θ f Represents a circular shift term, n f Indicates the frame number.

[0105] Case 2: When three radio frames are transmitted consecutively starting from an even-numbered frame, one radio frame in the first 90ms maps to the NSSS sequence, two radio frames in the second 90ms map to the NSSS sequence, and one radio frame in the third radio frame maps to the NSSS sequence. The cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0106] Where θ f Represents a circular shift term, n f Indicates the frame number.

[0107] Pattern 2: Four different NSSS sequences are mapped in two first TDD cycles; the four different NSSS sequences are cyclically mapped between radio frames used for downlink transmission, wherein only one subframe in each radio frame used for downlink transmission maps the NSSS sequence.

[0108] For example, as shown in Figure 12, three consecutive radio frames within a 90ms period are used for downlink transmission. An NSSS is transmitted in subframe #9 of each of the three radio frames, applying different cyclic shift values. The entire NSSS period is extended to 2*90ms. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0109] Where, θ f Represents a circular shift term, n f Indicates the frame number.

[0110] In the embodiments of this disclosure, the first period of the first TDD frame structure is a second value, one period of the first TDD frame structure contains N radio frames, and one period of the first TDD frame structure contains only one radio frame for downlink transmission.

[0111] Specifically, as stated above, the first TDD frame structure is a traditional TDD frame structure, where N can be 8 and the second value can be 80ms. This means that one period of the first TDD frame structure is 80ms, and this 80ms period includes one radio frame used for downlink transmission. The configuration method of the NSSS frame structure pattern information includes at least one of the following:

[0112] Pattern 1: Four different NSSS sequences are sequentially mapped between radio frames used for downlink transmission, and an NSSS sequence is mapped at a preset subframe position in each radio frame used for downlink transmission.

[0113] For example, in order to ensure that the NSSS sequence can be detected in the downlink frame activated in each 80ms period, at least one of the following methods is proposed:

[0114] Method 1: Map the NSSS sequence to a preset subframe position (available subframe position) on each radio frame used for downlink transmission. The original NSSS sequence transmitted on each radio frame is cyclically shifted once within an 80ms period; it is then cyclically shifted again within the next 80ms period, extending the entire NSSS period to 80*4ms. The cyclic shift values ​​for the four NSSS sequences within this period are different. For example, an NSSS sequence is mapped to subframe position #6 or #7. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0115] Where, θ f Represents a circular shift term, n f This indicates the frame number. The benefit of this is that it reduces downlink synchronization latency.

[0116] Method 2: As shown in Figure 13, an NSSS sequence is mapped at position #9 of subframe in each radio frame used for downlink transmission. The original NSSS sequence transmitted in a radio frame is cyclically shifted once within an 80ms period, and then cyclically shifted again within the next 80ms period. The entire NSSS period is extended to 80*4ms, and the cyclic shift values ​​of the four original NSSS sequences within the period are different. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0117] Where θ f Represents a circular shift term, n f Indicates the frame number.

[0118] Pattern 2: Maps two different NSSS sequences in each radio frame used for downlink transmission.

[0119] For example, as shown in Figure 14, to ensure that NSSS can be detected in each downlink frame active in every 80ms period, two different original NSSS sequences are mapped at preset subframe positions (two available subframe positions) in each radio frame used for downlink transmission. These two original NSSS sequences have different cyclic shift values. In the next 80ms period, two more different original NSSS sequences are mapped, with different cyclic shift values. The entire NSSS period is extended to 90*2, with four different cyclic shift values ​​for the four NSSS sequences within the period. For example, two NSSS sequences are mapped at subframes #8 and #9. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0120] Where, θ f Represents a circular shift term, n f Indicates the frame number, n p This indicates the subframe number. The benefit of doing this is that it further reduces synchronization time and improves timing accuracy.

[0121] Pattern 3: Four different NSSS sequences are mapped in each radio frame used for downlink transmission, and four different NSSS sequences are mapped at each radio frame used for downlink transmission or at the four preset subframe positions that activate downlink transmission.

[0122] For example, as shown in Figure 15, to ensure that the NSSS sequence can be detected in each downlink frame active in an 80ms period, four NSSS sequences are mapped to four preset subframe positions (available subframe positions) in each radio frame used for downlink transmission. The entire NSSS period is extended to 80ms, and the cyclic shift values ​​of the four NSSS sequences are different within the period. For example, four NSSS sequences are mapped to subframes #6, #7, #8, and #9. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0123] Where, θ f Represents a circular shift term, n p This indicates the subframe number. The benefit of doing this is that it further reduces synchronization time and improves timing accuracy.

[0124] In the embodiments of this disclosure, the first period of the first TDD frame structure in TDD mode is a second value, one period of the first TDD frame structure contains N radio frames, and one period of the first TDD frame structure contains only two radio frames for downlink transmission, the two radio frames for downlink transmission including a first radio frame for downlink transmission and a second radio frame for downlink transmission.

[0125] Specifically, as stated above, the first TDD frame structure is a traditional TDD frame structure, where N can be 8 and the second value can be 80ms. This means that one period of the first TDD frame structure is 80ms, and the 80ms period contains two radio frames used for downlink transmission. The configuration method of the NSSS frame structure pattern information includes at least one of the following:

[0126] Pattern 1: Four different NSSS sequences are sequentially mapped during each first TDD cycle, and an NSSS sequence is mapped in a preset subframe position in a second radio frame used for downlink transmission, wherein the first TDD cycle is the first cycle of the first TDD frame structure.

[0127] For example, as shown in Figure 16, the original NSSS sequence is transmitted on the first or second radio frame (even-numbered radio frame) for downlink transmission within an 80ms period, and then cyclically shifted once. This cyclic shift occurs again in the next 80ms period, extending the entire NSSS period to 80*4ms. The cyclic shift values ​​of the four original NSSS sequences within the period are different. The generation of the NSSS sequence is related to both the original NSSS sequence and the cyclic shift values. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0128] Where, θ f Represents a circular shift term, n f Indicates the frame number.

[0129] Pattern 2: Four different NSSS sequences are sequentially mapped between each radio frame used for downlink transmission.

[0130] For example, as shown in Figure 17, to reduce the timing period of the NSSS frame, subframe #9 of each of the two active radio frames used for downlink transmission is mapped to an original NSSS sequence, with different cyclic shift values ​​applied. Therefore, the timing period of the NSSS frame is shortened to 80ms*2. The generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on at least one of the following formulas:

[0131] Case 1: When two consecutive radio frames for downlink transmission are activated starting from an odd-numbered frame, the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0132] Where, θ f Represents a circular shift term, n f Indicates the frame number, n p Indicates the subframe number.

[0133] Case 2: When two consecutive radio frames for downlink transmission are activated starting from an even-numbered frame, the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0134] Where θ f Represents a circular shift term, n f Indicates the frame number, n p Indicates the subframe number.

[0135] Pattern 3: Two different NSSS sequences are mapped in each radio frame used for downlink transmission, and different NSSS sequences are mapped at two preset subframe positions in the first radio frame and at two preset subframe positions in the second radio frame.

[0136] For example, to reduce the timing period of the NSSS frame, two original NSSS sequences are mapped to subframes #8 and #9 or #6 and #9 in each of the two active radio frames used for downlink transmission. A total of four original NSSS sequences are mapped between the two downlink radio frames. Each original NSSS sequence applies a different cyclic shift value, thus shortening the timing period of the NSSS frame to 80ms. As shown in Figure 18, taking subframes #8 and #9 mapped to the radio frames used for downlink transmission as an example, the generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on at least one of the following formulas:

[0137] Case 1: When two consecutive radio frames are activated starting from an odd-numbered frame, the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0138] Where, θ f Represents a circular shift term, n f Indicates the frame number, n p Indicates the subframe number.

[0139] Case 2: When two consecutive radio frames are activated starting from an even-numbered frame, the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0140] Where, θ f Represents a circular shift term, n f Indicates the frame number, n p Indicates the subframe number.

[0141] Pattern 4: Two different NSSS sequences are mapped in each first TDD cycle, and different NSSS sequences are mapped in the two preset subframe positions of the second radio frame used for downlink transmission.

[0142] For example, to reduce the timing period of the NSSS frame, two original NSSS sequences are mapped to subframes #8 and #9 or #6 and #9 of the active second radio frame (even-numbered radio frame) used for downlink transmission. Each original NSSS sequence applies a different cyclic shift value, thus shortening the timing period of the NSSS frame to 80ms*2. As shown in Figure 19, taking subframes #8 and #9 of the radio frame used for downlink transmission as an example, the generation of the NSSS sequence is related to the original NSSS sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0143] Where, θ f Represents a circular shift term, n f Indicates the frame number, n p Indicates the subframe number.

[0144] Pattern 5: Four different NSSS sequences are mapped in each first TDD cycle; different NSSS sequences are mapped in the four preset subframe positions of each second radio frame.

[0145] For example, as shown in Figure 20, subframes #6, #7, 8, and #9, which are active for downlink transmission of the second radio frame (even-numbered radio frame), map four NSSS raw sequences. Each NSSS raw sequence applies a different cyclic shift value, thus shortening the NSSS frame timing period to 80ms*1. The generation of the NSSS sequence is related to the NSSS raw sequence and the cyclic shift value. The generation method of the NSSS sequence refers to protocol TS 36.211, where the cyclic shift value (i.e., the cyclic shift term) is determined based on the following formula:

[0146] Where, θ f Represents a circular shift term, n f Indicates the frame number, np Indicates the subframe number.

[0147] In the satellite communication method described above, the first information in step S100 includes several frame structure pattern information in TDD mode. One period of the first TDD frame structure in TDD mode includes M radio frames, and one period of the first TDD frame structure includes only one radio frame for downlink transmission. Furthermore, the first signal in step S200 includes an NPBCH, which carries a narrowband main information block (MIB-NB). The MIB-NB contains bit values ​​indicating the number of high-order bits of the frame information. The satellite communication method further includes: when the bit value is a first bit value, transmitting each NPBCH original sequence eight times; when the bit value is a second bit value, transmitting each NPBCH original sequence four times; when the bit value is a third bit value, transmitting each NPBCH original sequence twice; and when the bit value is a fourth bit value, transmitting each NPBCH original sequence once.

[0148] Specifically, if M is 9, the period of the first TDD frame structure is 90ms, and the first TDD frame structure contains 9 radio frames, only one of which is used for downlink transmission. Furthermore, in the NPBCH legacy design, the system frame number ranges from 0 to 1023, typically indicated by 10 bits. UE120 can directly decode the MIB-NB in ​​the NPBCH to obtain the 4-bit system frame number information of the high-order MSB. Additionally, the 6-bit frame information is implicitly indicated by decoding the NPBCH. Specifically, the cell's NPBCH needs to be transmitted through 8 NPBCH blocks, implicitly indicating 3 bits. Each NPBCH block is repeatedly transmitted and applies 8 different scrambling sequences, implicitly indicating 3 bits. Therefore, a total of 6 bits are implicitly indicated. From the above information, it can be concluded that the high-order bit value of the frame information is the first bit value (e.g., 4 bits). In this case, each original NPBCH sequence is repeatedly transmitted eight times. In TDD mode, to reduce the transmission cycle of NPBCH, the number of bits for direct decoding of MSB can be increased to N (N>4). This reduces the number of bits required for frame information to 10-N. If the number of NPBCH blocks remains unchanged, the number of times each NPBCH block needs to be retransmitted is implicitly specified, with 7-N bits implicitly specified. Therefore, each NPBCH block needs to be transmitted 2^(7-N) times. This can be achieved by retransmitting on subframes within the radio frame, starting from a preset subframe position, such as subframe #0, and mapping 2^(5-N), 2^(6-N), or 2^(7-N) times respectively. Transmitting one block requires 2^(7-N), 2^(6-N), or 2^(5-N) 90ms cycles. In other words, if the high-order bits of the frame information are the second bit value (5 bits), then each NPBCH original sequence is transmitted four times; if the high-order bits of the frame information are the third bit value (6 bits), then each NPBCH original sequence is transmitted twice; if the high-order bits of the frame information are the fourth bit value (7 bits), then each NPBCH original sequence is transmitted once.

[0149] In embodiments of this disclosure, as shown in FIG21, each radio frame for downlink transmission includes a preset subframe for transmitting an NPBCH sequence, and the configuration method of the NPBCH frame structure pattern information includes at least one of the following:

[0150] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0151] For example, an NPBCH sequence is transmitted at a preset subframe position in each radio frame used for downlink transmission. Since each original NPBCH sequence is transmitted eight times, each time with a different scrambling sequence, it takes 8*90ms to transmit one original NPBCH sequence (NPBCH block), and 8*8*90ms to transmit eight NPBCH blocks. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0152] Where, n f Indicates the wireless frame number. Indicates the physical ID of the community.

[0153] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0154] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the other 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits of indication, and each NPBCH block is transmitted four times to provide the final 2 bits of frame information. An NPBCH sequence is mapped starting at position #0 of the radio intraframe used for downlink transmission within 90ms. Transmitting one NPBCH block four times takes 4 * 90ms, with a different scrambling sequence applied each time. Transmitting all eight NPBCH blocks takes 8 * 4 * 90ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0155] Where, n f Indicates the wireless frame number. Community physical ID.

[0156] MasterInformationBlock-NB::=SEQUENCE{

[0157] systemFrameNumber-MSB-r13 BIT STRING(SIZE(5)),

[0158] hyperSFN-LSB-r13 BIT STRING(SIZE(2)),

[0159] schedulingInfoSIB1-r13 INTEGER(0..15),

[0160] systemInfoValueTag-r13 INTEGER(0..31),

[0161] ab-Enabled-r13 BOOLEAN,

[0162] operationModeInfo-r13 CHOICE{

[0163] inband-SamePCI-r13 Inband-SamePCI-NB-r13,

[0164] inband-DifferentPCI-r13 Inband-DifferentPCI-NB-r13,

[0165] guardband-r13 Guardband-NB-r13,

[0166] standalone-r13 Standalone-NB-r13

[0167] },

[0168] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0169] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 6 bits, the remaining 4 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted twice to provide the final 1 bit. An NPBCH sequence is mapped starting at position #0 of the radio intraframe subframe used for downlink transmission within 90ms. Transmitting one NPBCH block twice takes 2 * 90ms, with a different scrambling sequence applied each time. Transmitting all eight NPBCH blocks takes 8 * 2 * 90ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0170] Where, n f Indicates a wireless frame. Community physical ID.

[0171] MasterInformationBlock-NB::=SEQUENCE{

[0172] systemFrameNumber-MSB-r13 BIT STRING(SIZE(6)),

[0173] hyperSFN-LSB-r13 BIT STRING(SIZE(2)),

[0174] schedulingInfoSIB1-r13 INTEGER(0..15),

[0175] systemInfoValueTag-r13 INTEGER(0..31),

[0176] ab-Enabled-r13 BOOLEAN,

[0177] operationModeInfo-r13 CHOICE{

[0178] inband-SamePCI-r13 Inband-SamePCI-NB-r13,

[0179] inband-DifferentPCI-r13 Inband-DifferentPCI-NB-r13,

[0180] guardband-r13 Guardband-NB-r13,

[0181] standalone-r13 Standalone-NB-r13

[0182] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0183] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 7 bits, the other 3 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted once. One NPBCH sequence is mapped starting from position #0 of the radio intraframe subframe used for downlink transmission within 90ms. Transmitting all eight NPBCH blocks takes 8 * 1 * 90ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0184] in, Community physical ID.

[0185] MasterInformationBlock-NB::=SEQUENCE{

[0186] systemFrameNumber-MSB-r13 BIT STRING(SIZE(7)),

[0187] hyperSFN-LSB-r13 BIT STRING(SIZE(2)),

[0188] schedulingInfoSIB1-r13 INTEGER(0..15),

[0189] systemInfoValueTag-r13 INTEGER(0..31),

[0190] ab-Enabled-r13 BOOLEAN,

[0191] operationModeInfo-r13 CHOICE{

[0192] inband-SamePCI-r13 Inband-SamePCI-NB-r13,

[0193] inband-DifferentPCI-r13 Inband-DifferentPCI-NB-r13,

[0194] guardband-r13 Guardband-NB-r13,

[0195] standalone-r13 Standalone-NB-r13

[0196] },

[0197] In embodiments of this disclosure, as shown in FIG22, each radio frame for downlink transmission includes two preset subframes for transmitting NPBCH sequences, and the configuration of the NPBCH frame structure pattern information includes at least one of the following:

[0198] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0199] For example, the same NPBCH block is repeatedly transmitted twice at two preset subframe positions (available subframe positions) in a radio frame, each time applying a different scrambling sequence. Transmitting one NPBCH block takes a period of 4*90ms. Therefore, transmitting 8 NPBCH blocks takes 8*4*90ms. For instance, two NPBCH sequences are mapped to subframes #0 and #1 of each radio frame used for downlink transmission. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0200] Where, n f Indicates the wireless frame number, n p The subframe number can be 0-1. Indicates the physical ID of the community.

[0201] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0202] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the remaining 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted four times to provide the final 2 bits. Two NPBCH sequences are mapped at two preset subframe positions (available subframe positions) within the radio frame used for downlink transmission within 90ms. Transmitting one NPBCH block four times requires 2 * 90ms, and transmitting all eight NPBCH blocks requires 8 * 2 * 90ms. For example, mapping two NPBCH sequences at subframes #0 and #1. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0203] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Community physical ID.

[0204] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0205] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 6 bits, the remaining 4 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted twice to provide the final 1 bit. Within 90ms, subframe positions #0 and #1 of the radio frame used for downlink transmission map two NPBCH sequences. Transmitting one NPBCH block twice takes 1*90ms, and transmitting all eight NPBCH blocks takes 8*1*90ms. For example, mapping two NPBCH sequences at subframe positions #0 and #1, the generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0206] Where n p Indicates the subframe number. Community physical ID.

[0207] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0208] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 7 bits, the remaining 3 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted once. Two NPBCH sequences are mapped starting at two preset subframe positions (available subframe positions) within the radio frame used for downlink transmission within 90ms. Transmitting all eight NPBCH blocks takes 4*1*90ms. For example, two NPBCH sequences are mapped at subframes #0 and #1. The generation of the NPBCH sequences is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequences refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0209] in Indicates the community ID.

[0210] In embodiments of this disclosure, as shown in FIG23, each radio frame for downlink transmission includes four preset subframes for transmitting NPBCH sequences, and the configuration of the NPBCH frame structure pattern information includes at least one of the following:

[0211] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0212] For example, the same NPBCH block is repeatedly transmitted four times at four preset subframe positions (available subframe positions) in a radio frame. Transmitting one NPBCH block takes a period of 2*90ms. If an NPBCH block is repeatedly transmitted within this period but with different scrambling sequences, transmitting eight NPBCH blocks takes 8*2*90ms. For instance, four NPBCH sequences are mapped at subframes #0, #1, #2, and #3. The generation of the NPBCH sequences is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequences refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0213] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Community physical ID.

[0214] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0215] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the remaining 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted four times to provide the final 2 bits. Four NPBCH sequences are mapped at four preset subframe positions (available subframe positions) within the radio frame used for downlink transmission within 90ms. Transmitting one NPBCH block four times requires 1*90ms, and transmitting all eight NPBCH blocks requires 8*1*90ms. For example, four NPBCH sequences are mapped at subframes #0, #1, #2, and #3. The generation of the NPBCH sequences is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequences refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0216] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Community physical ID.

[0217] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0218] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 6 bits, the remaining 4 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted twice to provide the final 1 bit. Four NPBCH sequences are mapped at four preset subframe positions (available subframe positions) within the radio frame used for downlink transmission within 90ms. Transmitting all eight NPBCH blocks takes 4 * 1 * 90ms. For example, four NPBCH sequences are mapped at subframes #0, #1, #2, and #3. The generation of the NPBCH sequences is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequences refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0219] Where n fIndicates the wireless frame number, n p Indicates the subframe number. Community physical ID.

[0220] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0221] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 7 bits, the remaining 3 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted once. Four NPBCH sequences are mapped to four preset subframe positions (available subframe positions) within the radio frame used for downlink transmission within 90ms. Transmitting all eight NPBCH blocks takes 2*1*90ms. For example, four NPBCH sequences are mapped to subframes #0, #1, #2, and #3. The generation of the NPBCH sequences is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequences refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0222] in Indicates the community ID.

[0223] Furthermore, as discussed earlier in the embodiments of this disclosure, the first information in step S100 also includes a second TDD frame structure in TDD mode, a second period of the second TDD frame structure, the number of subframes included in the activation of downlink transmission, and the configuration method for activating downlink transmission, etc., which will not be repeated here.

[0224] In embodiments of this disclosure, each active downlink transmission includes a preset subframe for transmitting an NPBCH sequence, and the configuration of the NPBCH frame structure pattern information includes at least one of the following:

[0225] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0226] For example, the NPBCH of a cell is divided into 8 blocks, and each NPBCH block is transmitted repeatedly 8 times. Transmitting one NPBCH block for each active downlink transmission takes 8*90ms. Each 90ms period involves transmitting the same NPBCH block 8 times with different scrambling sequences. Transmitting all 8 NPBCH blocks takes 8*8*90ms. For example, at subframe #0, the generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0227] Where n f Indicates the wireless frame number. Indicates the community ID.

[0228] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0229] For example, transmitting one NPBCH block for each active downlink transmission takes 4*90ms. Each NPBCH block is transmitted four times, using different scrambling sequences. Two bits are used to implicitly indicate system frame information. The high-order bits used to indicate frame information in the configured MIB-NB are 5 bits. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0230] Where n f Indicates the wireless frame number. Indicates the community ID.

[0231] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0232] For example, transmitting one NPBCH block for each active downlink transmission takes 2*90ms. Each NPBCH block is transmitted twice, applying different scrambling sequences. One bit is used to implicitly indicate system frame information. The configured MIB-NB has 6 bits for indicating frame information, plus the 3 bits for the 8 NPBCH blocks, for a total of 10 bits for indicating system frame information. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0233] Where n f Indicates the wireless frame number. Indicates the community ID.

[0234] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0235] For example, transmitting one NPBCH block for each active downlink transmission takes 1*90ms. Each NPBCH block is transmitted once. The configured MIB-NB has 7 high-order bits used to indicate frame information, plus 3 bits for the 8 NPBCH blocks, for a total of 10 bits used to indicate system frame information. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0236] in Indicates the community ID.

[0237] In embodiments of this disclosure, each active downlink transmission includes two preset subframes for transmitting NPBCH sequences, and the configuration of the NPBCH frame structure pattern information includes at least one of the following:

[0238] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0239] For example, in each active downlink transmission, the two NPBCH sequences belong to the same NPBCH block. Transmitting one NPBCH block takes 4*90ms. Repeating the transmission of the NPBCH block eight times with different scrambling sequences, it takes 8*4*90ms to transmit all eight NPBCH blocks. For instance, two NPBCH sequences are mapped at positions #0 and #1 in subframes. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0240] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the community ID.

[0241] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0242] For example, in each active downlink transmission, the two NPBCH sequences belong to the same NPBCH block. Each NPBCH block is transmitted four times. Transmitting one NPBCH block takes 2*90ms, and transmitting eight NPBCH blocks takes 8*2*90ms. When the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the remaining 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and the final 2 bits are provided by transmitting each NPBCH block four times. For example, two NPBCH sequences are mapped at positions #0 and #1 in subframes. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0243] Where, n f Indicates the wireless frame number, n p Indicates the subframe number. Community physical ID.

[0244] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0245] For example, in each active downlink transmission, the two NPBCH sequences belong to the same NPBCH block. Each NPBCH block is transmitted twice, and transmitting one NPBCH block takes 1*90ms. One bit is used to indicate system frame information. Transmitting all eight NPBCH blocks takes 8*90ms. The high-order bits used to indicate frame information in the MIB-NB configuration are 6 bits, plus the 3 bits used to indicate the eight NPBCH blocks, for a total of 10 bits used to indicate system frame information. For example, two NPBCH sequences are mapped at positions #0 and #1 in subframes. The generation of the NPBCH sequences is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequences refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0246] Where n p Indicates the subframe number. Community physical ID.

[0247] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0248] For example, the two NPBCH sequences in each active downlink transmission belong to two different NPBCH blocks. Each NPBCH block is transmitted repeatedly once, and it takes 4 * 90 ms to transmit all 8 NPBCH blocks. The high-order bits used to indicate frame information in the MIB-NB configuration are 7 bits, plus the 3 bits indicating the 8 NPBCH blocks, for a total of 10 bits used to indicate system frame information. For example, two NPBCH sequences are mapped at positions #0 and #1 in subframes. The generation of the NPBCH sequences is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequences refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0249] in Community physical ID.

[0250] In the satellite communication method described above, the first information in step S100 includes several frame structure pattern information in TDD mode. One period of the first TDD frame structure in TDD mode includes M (e.g., 9) radio frames, and one period of the first TDD frame structure includes two radio frames for downlink transmission. Furthermore, the first signal in step S200 includes NPBCH, the content of which is as described above and will not be repeated here.

[0251] In embodiments of this disclosure, as shown in FIG24, each radio frame for downlink transmission includes a preset subframe for transmitting an NPBCH sequence, and the configuration method of the NPBCH frame structure pattern information includes at least one of the following:

[0252] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0253] For example, the NPBCH sequence is mapped to subframe #0 of each radio frame used for downlink transmission. The NPBCH of a cell is divided into 8 NPBCH blocks, and each NPBCH block is repeated 8 times in the 8 radio frames. Therefore, it takes 8 * 4 * 90 ms to transmit 64 NPBCH sequences. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on at least one of the following formulas:

[0254] Case 1: Two radio frames are transmitted starting from an odd-numbered offset frame within the period. The mask sequence initialization is determined based on the following formula:

[0255] Where, n f Indicates the wireless frame number. Indicates the cell ID.

[0256] Case 2: Two radio frames are transmitted starting from an even-numbered offset frame within the period. The mask sequence initialization is determined based on the following formula:

[0257] Where, n f Indicates the wireless frame number. Indicates the cell ID.

[0258] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0259] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the remaining 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted four times to provide the final 2 bits. Within two radio frames used for downlink transmission, one NPBCH sequence is mapped starting from subframe position #0. Transmitting the same NPBCH block four times takes 2*90ms, and transmitting all eight NPBCH blocks takes 8*2*90ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on at least one of the following formulas:

[0260] Case 1: Two radio frames are transmitted starting from an odd-numbered offset frame within the period. The mask sequence initialization is determined based on the following formula:

[0261] Where n f Indicates the wireless frame number. Indicates the cell ID.

[0262] Case 2: Two radio frames are transmitted starting from an even-numbered offset frame within the period. The mask sequence initialization is determined based on the following formula:

[0263] Where, n f Indicates the wireless frame number. Indicates the cell ID.

[0264] MasterInformationBlock-NB::=SEQUENCE{

[0265] systemFrameNumber-MSB-r13 BIT STRING(SIZE(5)),

[0266] hyperSFN-LSB-r13 BIT STRING(SIZE(2)),

[0267] schedulingInfoSIB1-r13 INTEGER(0..15),

[0268] systemInfoValueTag-r13 INTEGER(0..31),

[0269] ab-Enabled-r13 BOOLEAN,

[0270] operationModeInfo-r13 CHOICE{

[0271] inband-SamePCI-r13 Inband-SamePCI-NB-r13,

[0272] inband-DifferentPCI-r13 Inband-DifferentPCI-NB-r13,

[0273] guardband-r13 Guardband-NB-r13,

[0274] standalone-r13 Standalone-NB-r13

[0275] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0276] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 6 bits, the remaining 4 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted twice to provide the final 1 bit. One NPBCH sequence is mapped at subframe position #0 within two radio frames used for downlink transmission. Transmitting the same NPBCH block twice takes 90ms, and transmitting all eight NPBCH blocks takes 8 * 1 * 90ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on at least one of the following formulas:

[0277] Case 1: Starting from the odd-numbered offset frame within the period, two consecutive radio frames are activated. The mask sequence initialization is determined based on the following formula:

[0278] Where n f Indicates the wireless frame number. Indicates the cell ID.

[0279] Case 2: Starting from an even-numbered offset frame within the period, two consecutive radio frames are activated. The mask sequence initialization is determined based on the following formula:

[0280] Where n f Indicates the wireless frame number. Indicates the cell ID.

[0281] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0282] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 7 bits, the remaining 3 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted once. One NPBCH sequence is mapped at subframe position #0 within two radio frames used for downlink transmission. Transmitting all eight NPBCH blocks takes 4 * 1 * 90 ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0283] in Indicates the community ID.

[0284] In embodiments of this disclosure, as shown in FIG25, each radio frame for downlink transmission includes two preset subframes for transmitting NPBCH sequences, and the configuration of the NPBCH frame structure pattern information includes at least one of the following:

[0285] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0286] For example, in two radio frames used for downlink transmission, the same NPBCH block is repeatedly transmitted twice on subframes #0 and #1 of each radio frame, with a different scrambling sequence applied each time. Transmitting one NPBCH block takes 2*90ms, and transmitting 8 NPBCH blocks takes 8*2*90ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on at least one of the following formulas:

[0287] Case 1: Starting from the odd-numbered offset frame within the period, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0288] Where nf Indicates the wireless frame number, n p Indicates the subframe number. Indicates the cell ID.

[0289] Case 2: Starting from an even-numbered offset frame within the period, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0290] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the cell ID.

[0291] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0292] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the remaining 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted four times to provide the final 2 bits. Two NPBCH sequences are mapped at subframe positions #0 and #1 within two radio frames used for downlink transmission. Transmitting the same NPBCH block four times takes 90ms, and transmitting all eight NPBCH blocks takes 8*1*90ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on at least one of the following formulas:

[0293] Case 1: Starting from the odd-numbered offset frame within the period, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0294] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the cell ID.

[0295] Case 2: Starting from an even-numbered offset frame within the period, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0296] Where n fIndicates the wireless frame number, n p Indicates the subframe number. Indicates the cell ID.

[0297] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0298] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 6 bits, the remaining 4 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted twice to provide the final 1 bit. Two NPBCH sequences are mapped at subframe positions #0 and #1 within two radio frames used for downlink transmission. Two NPBCH blocks are transmitted within a 90ms period, and transmitting all eight NPBCH blocks takes 4 * 90ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0299] Where n p Indicates the subframe number. Indicates the community ID.

[0300] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0301] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 7 bits, the remaining 3 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits each, and each NPBCH block is transmitted once. Transmitting all eight NPBCH blocks takes 2 * 90 ms, using a middle mask sequence:

[0302] in Indicates the community ID.

[0303] In embodiments of this disclosure, as shown in FIG26, each radio frame for downlink transmission includes four preset subframes for transmitting NPBCH sequences, and the configuration of the NPBCH frame structure pattern information includes at least one of the following:

[0304] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0305] For example, the same NPBCH block is repeatedly transmitted four times on a subframe of a radio frame used for downlink transmission, with a different scrambling sequence applied each time. Transmitting one NPBCH block takes 90ms, and transmitting eight NPBCH blocks takes 8*1*90ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, wherein the mask sequence initialization is determined based on at least one of the following formulas:

[0306] Case 1: Starting from the odd-numbered offset frame within the period, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0307] Where, n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the cell ID.

[0308] Case 2: Starting from an even-numbered offset frame within the period, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0309] Where, n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the cell ID.

[0310] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0311] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the remaining 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted four times to provide the final 2 bits. Four NPBCH sequences are mapped at subframe positions #0, #1, #2, and #3 within two radio frames used for downlink transmission. One NPBCH block is transmitted repeatedly within a radio frame used for downlink transmission. Transmitting all eight NPBCH blocks takes 4 * 90 ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0312] Where, n p Indicates the subframe number. Indicates the community ID.

[0313] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0314] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 6 bits, the remaining 4 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted twice to provide the final 1 bit. Four NPBCH sequences are mapped at subframe positions #0, #1, #2, and #3 within two radio frames used for downlink transmission. Transmitting all eight NPBCH blocks takes 2 * 90 ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0315] Where n p Indicates the subframe number. Indicates the community ID.

[0316] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0317] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 7 bits, the remaining 3 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted once. Four NPBCH sequences are mapped at subframe positions #0, #1, #2, and #3 within two radio frames used for downlink transmission. Transmitting all eight NPBCH blocks takes 1*90ms. For the method of generating NPBCH sequences, refer to the LTE method in TS 36.311, where the mask sequence initialization is based on the following form:

[0318] in Indicates the community ID.

[0319] In the satellite communication method described above, the first information in step S100 includes several frame structure pattern information in TDD mode. One period of the first TDD frame structure in TDD mode includes M (e.g., 9) radio frames, and one period of the first TDD frame structure includes three radio frames for downlink transmission. Furthermore, the first signal in step S200 includes NPBCH, the content of which is as described above and will not be repeated here.

[0320] In embodiments of this disclosure, as shown in FIG27, each radio frame for downlink transmission includes a preset subframe for transmitting an NPBCH sequence, and the configuration method of the NPBCH frame structure pattern information includes at least one of the following:

[0321] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0322] For example, the NPBCH sequence is mapped to subframe #0 of each radio frame used for downlink transmission. A cell's NPBCH is divided into 8 NPBCH blocks, and each NPBCH block is repeated 8 times in the 8 radio frames. Therefore, it takes 8 * 3 * 90 ms to transmit the entire NPBCH sequence. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0323] Case 1: Starting from the odd-numbered offset frames within the period, three consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0324] Where, n f Indicates the wireless frame number, np Indicates the subframe number. Indicates the cell ID.

[0325] Case 2: Starting from an even-numbered offset frame within the period, three consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0326] Where, n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the cell ID.

[0327] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0328] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the remaining 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted four times to provide the final 2 bits. Within three radio frames used for downlink transmission, one NPBCH sequence is mapped starting from subframe position #0. Transmitting the same NPBCH block four times takes 2 * 90 ms, and transmitting all eight NPBCH blocks takes 8 * 2 * 90 ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0329] Case 1: Starting from the odd-numbered offset frames within the period, activate three consecutive radio frames for downlink transmission.

[0330] Where n f Indicates the wireless frame number. Indicates the cell ID.

[0331] Case 2: Starting from an even-numbered offset frame within the period, activate three consecutive radio frames for downlink transmission.

[0332] Where n f Indicates the wireless frame number. Indicates the community ID.

[0333] MasterInformationBlock-NB::=SEQUENCE{

[0334] systemFrameNumber-MSB-r13 BIT STRING(SIZE(5)),

[0335] hyperSFN-LSB-r13 BIT STRING(SIZE(2)),

[0336] schedulingInfoSIB1-r13 INTEGER(0..15),

[0337] systemInfoValueTag-r13 INTEGER(0..31),

[0338] ab-Enabled-r13 BOOLEAN,

[0339] operationModeInfo-r13 CHOICE{

[0340] inband-SamePCI-r13 Inband-SamePCI-NB-r13,

[0341] inband-DifferentPCI-r13 Inband-DifferentPCI-NB-r13,

[0342] guardband-r13 Guardband-NB-r13,

[0343] standalone-r13 Standalone-NB-r13

[0344] },

[0345] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0346] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 6 bits, the remaining 4 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted twice to provide the final 1 bit. One NPBCH sequence is mapped at subframe position #0 within three radio frames used for downlink transmission. Transmitting the same NPBCH block twice takes 90ms, and transmitting all eight NPBCH blocks takes 8 * 1 * 90ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0347] Case 1: Starting from the odd-numbered offset frames within the period, activate three consecutive radio frames for downlink transmission.

[0348] Where n f Indicates the wireless frame number. Indicates the cell ID.

[0349] Case 2: Starting from an even-numbered offset frame within the period, activate three consecutive radio frames for downlink transmission.

[0350] Where n f Indicates the wireless frame number. Indicates the community ID.

[0351] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0352] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 7 bits, the remaining 3 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted once. One NPBCH sequence is mapped at subframe position #0 within three radio frames used for downlink transmission. Transmitting all eight NPBCH blocks takes 3 * 1 * 90 ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0353] in Indicates the community ID.

[0354] In embodiments of this disclosure, as shown in FIG28, each radio frame for downlink transmission includes two preset subframes for transmitting NPBCH sequences, and the configuration of the NPBCH frame structure pattern information includes at least one of the following:

[0355] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0356] For example, the same NPBCH block is repeatedly transmitted twice on subframes #0 and #1 of a radio frame used for downlink transmission, with a different scrambling sequence applied each time. Transmitting one NPBCH block takes 2*90ms, and transmitting 8 NPBCH blocks takes 11*90ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, wherein the initialization of the mask sequence is determined based on at least one of the following formulas:

[0357] Case 1: Starting from the odd-numbered offset frames within the period, three consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0358] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the cell ID.

[0359] Case 2: Starting from an even-numbered offset frame within the period, three consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0360] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the cell ID.

[0361] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0362] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the remaining 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted four times to provide the final 2 bits. Two NPBCH sequences are mapped at subframe positions #0 and #1 in the three radio frames used for downlink transmission. Transmitting the same NPBCH block four times takes 90ms, and transmitting all eight NPBCH blocks takes 8*1*90ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on at least one of the following formulas:

[0363] Case 1: Starting from the odd-numbered offset frames within the period, three consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0364] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the cell ID.

[0365] Case 2: Starting from an even-numbered offset frame within the period, three consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0366] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the cell ID.

[0367] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0368] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 6 bits, the remaining 4 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted twice to provide the final 1 bit. Two NPBCH sequences are mapped at subframe positions #0 and #1 within the three radio frames used for downlink transmission. Two NPBCH blocks are transmitted within a 90ms period, and transmitting all eight NPBCH blocks takes 4 * 90ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0369] Where n p Indicates the subframe number. Indicates the community ID.

[0370] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0371] For example, when the high-order bits used to indicate frame information in the configured MIB-NB are 7 bits, the remaining 3 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, each NPBCH block is transmitted once, and transmitting all eight NPBCH blocks takes 2 * 90 ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0372] in Indicates the community ID.

[0373] In embodiments of this disclosure, as shown in FIG29, each radio frame for downlink transmission includes four preset subframes for transmitting NPBCH sequences, and the configuration of the NPBCH frame structure pattern information includes at least one of the following:

[0374] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0375] For example, the same NPBCH block is repeatedly transmitted four times in each subframe of a radio frame used for downlink transmission, with a different scrambling sequence applied each time. Transmitting one NPBCH block takes 90ms, and transmitting eight NPBCH blocks takes 6*1*90ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, wherein the mask sequence initialization is determined based on at least one of the following formulas:

[0376] Case 1: Starting from the odd-numbered offset frames within the period, three consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0377] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the cell ID.

[0378] Case 2: Starting from an even-numbered offset frame within the period, three consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0379] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the cell ID.

[0380] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0381] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the remaining 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted four times to provide the final 2 bits. Four NPBCH sequences are mapped at subframe positions #0, #1, #2, and #3 within three radio frames used for downlink transmission. One NPBCH block is transmitted repeatedly within a radio frame used for downlink transmission. Transmitting all eight NPBCH blocks takes 3 * 90 ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0382] Where n p Indicates the subframe number. Indicates the community ID.

[0383] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0384] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 6 bits, the remaining 4 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted twice to provide the final 1 bit. Four NPBCH sequences are mapped at subframe positions #0, #1, #2, and #3 within the three radio frames used for downlink transmission. Transmitting all eight NPBCH blocks takes 2 * 90 ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0385] Where n p Indicates the subframe number. Indicates the community ID.

[0386] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0387] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 7 bits, the remaining 3 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted once. Four NPBCH sequences are mapped at subframe positions #0, #1, #2, and #3 within the three radio frames used for downlink transmission. Transmitting all eight NPBCH blocks takes 1*90ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0388] in Indicates the community ID.

[0389] In the satellite communication method described above, the first information in step S100 includes several frame structure pattern information in TDD mode. One period of the first TDD frame structure in TDD mode includes N (e.g., 8) radio frames, meaning the period of the first TDD frame structure is 80ms. One period of the first TDD frame structure includes only one radio frame used for downlink transmission. Furthermore, the first signal in step S200 includes NPBCH, which has been discussed previously and will not be repeated here.

[0390] In embodiments of this disclosure, each radio frame for downlink transmission includes a preset subframe for transmitting an NPBCH sequence, and the configuration of the NPBCH frame structure pattern information includes at least one of the following:

[0391] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0392] For example, the same NPBCH block is transmitted once on subframe #0 of a radio frame used for downlink transmission. Transmitting one NPBCH block takes an 8*80ms period. Each NPBCH block transmitted within this period contains the same content but is equipped with a different scrambling sequence. Transmitting eight NPBCH blocks takes 8*8*80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0393] Where n f Indicates the wireless frame number. Indicates the physical ID of the community.

[0394] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0395] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the remaining 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted four times to provide the final 2 bits. One NPBCH sequence is mapped starting from position #0 of the radio intraframe used for downlink transmission within 80ms. Transmitting one NPBCH block four times requires 4 * 80ms, and transmitting all eight NPBCH blocks requires 8 * 4 * 80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0396] Where n f Indicates the wireless frame number. Community physical ID.

[0397] MasterInformationBlock-NB::=SEQUENCE{

[0398] systemFrameNumber-MSB-r13 BIT STRING(SIZE(5)),

[0399] hyperSFN-LSB-r13 BIT STRING(SIZE(2)),

[0400] schedulingInfoSIB1-r13 INTEGER(0..15),

[0401] systemInfoValueTag-r13 INTEGER(0..31),

[0402] ab-Enabled-r13 BOOLEAN,

[0403] operationModeInfo-r13 CHOICE{

[0404] inband-SamePCI-r13 Inband-SamePCI-NB-r13,

[0405] inband-DifferentPCI-r13 Inband-DifferentPCI-NB-r13,

[0406] guardband-r13 Guardband-NB-r13,

[0407] standalone-r13 Standalone-NB-r13

[0408] },

[0409] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0410] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 6 bits, the remaining 4 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted twice to provide the final 1 bit. An NPBCH sequence is mapped starting at position #0 of the radio intraframe used for downlink transmission within 80ms. Transmitting one NPBCH block twice requires 2 * 80ms, and transmitting all eight NPBCH blocks requires 8 * 2 * 80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0411] Where n f Indicates the wireless frame number. Community physical ID.

[0412] MasterInformationBlock-NB::=SEQUENCE{

[0413] systemFrameNumber-MSB-r13 BIT STRING(SIZE(6)),

[0414] hyperSFN-LSB-r13 BIT STRING(SIZE(2)),

[0415] schedulingInfoSIB1-r13 INTEGER(0..15),

[0416] systemInfoValueTag-r13 INTEGER(0..31),

[0417] ab-Enabled-r13 BOOLEAN,

[0418] operationModeInfo-r13 CHOICE{

[0419] inband-SamePCI-r13 Inband-SamePCI-NB-r13,

[0420] inband-DifferentPCI-r13 Inband-DifferentPCI-NB-r13,

[0421] guardband-r13 Guardband-NB-r13,

[0422] standalone-r13 Standalone-NB-r13

[0423] },

[0424] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0425] For example, when the high-order bits used to indicate frame information in the configured MIB-NB are 7 bits, the remaining 3 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted once. Within an 80ms radio frame used for downlink transmission, one NPBCH sequence is mapped starting from subframe position #0. Retransmitting all eight NPBCH blocks takes 8 * 1 * 80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0426] in, Community physical ID.

[0427] MasterInformationBlock-NB::=SEQUENCE{

[0428] systemFrameNumber-MSB-r13 BIT STRING(SIZE(7)),

[0429] hyperSFN-LSB-r13 BIT STRING(SIZE(2)),

[0430] schedulingInfoSIB1-r13 INTEGER(0..15),

[0431] systemInfoValueTag-r13 INTEGER(0..31),

[0432] ab-Enabled-r13 BOOLEAN,

[0433] operationModeInfo-r13 CHOICE{

[0434] inband-SamePCI-r13 Inband-SamePCI-NB-r13,

[0435] inband-DifferentPCI-r13 Inband-DifferentPCI-NB-r13,

[0436] guardband-r13 Guardband-NB-r13,

[0437] standalone-r13 Standalone-NB-r13

[0438] },

[0439] In embodiments of this disclosure, each radio frame for downlink transmission includes two preset subframes for transmitting NPBCH sequences, and the configuration of the NPBCH frame structure pattern information includes at least one of the following:

[0440] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0441] For example, the same NPBCH block is repeatedly transmitted twice on subframes #0 and #1 of a radio frame used for downlink transmission. Transmitting one NPBCH block takes a period of 4 * 80 ms. Each NPBCH block transmitted within this period contains the same content but is equipped with a different scrambling sequence. Transmitting eight NPBCH blocks takes 8 * 4 * 80 ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0442] Where, n f Indicates the wireless frame number, n p Indicates the subframe number. Community physical ID.

[0443] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0444] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the remaining 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted four times to provide the final 2 bits. Two NPBCH sequences are mapped starting from subframe positions #0 and #1 within an 80ms radio frame used for downlink transmission. Transmitting one NPBCH block four times requires 2 * 80ms, and transmitting all eight NPBCH blocks requires 8 * 2 * 80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0445] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Community physical ID.

[0446] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0447] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 6 bits, the remaining 4 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted twice to provide the final 1 bit. Two NPBCH sequences are mapped starting from subframe positions #0 and #1 within an 80ms radio frame used for downlink transmission. Transmitting one NPBCH block twice requires 1*80ms, and transmitting all eight NPBCH blocks requires 8*1*80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0448] Where n p Indicates the subframe number. Community physical ID.

[0449] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0450] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 7 bits, the remaining 3 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted once. Within 80ms, the subframe positions #0 and #1 of the radio frame used for downlink transmission are mapped to two NPBCH sequences. Retransmitting all eight NPBCH blocks takes 4 * 1 * 80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0451] in Indicates the community ID.

[0452] MasterInformationBlock-NB::=SEQUENCE{

[0453] systemFrameNumber-MSB-r13 BIT STRING(SIZE(7)),

[0454] hyperSFN-LSB-r13 BIT STRING(SIZE(2)),

[0455] schedulingInfoSIB1-r13 INTEGER(0..15),

[0456] systemInfoValueTag-r13 INTEGER(0..31),

[0457] ab-Enabled-r13 BOOLEAN,

[0458] operationModeInfo-r13 CHOICE{

[0459] inband-SamePCI-r13 Inband-SamePCI-NB-r13,

[0460] inband-DifferentPCI-r13 Inband-DifferentPCI-NB-r13,

[0461] guardband-r13 Guardband-NB-r13,

[0462] standalone-r13 Standalone-NB-r13

[0463] },

[0464] In embodiments of this disclosure, each radio frame for downlink transmission includes four preset subframes for transmitting NPBCH sequences, and the configuration of the NPBCH frame structure pattern information includes at least one of the following:

[0465] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0466] For example, the same NPBCH block is repeatedly transmitted four times on subframes #0, #1, #2, and #3 of a radio frame used for downlink transmission. Transmitting one NPBCH block takes a period of 2 * 80 ms. Each NPBCH block transmitted within this period contains the same content but is equipped with a different scrambling sequence. Transmitting eight NPBCH blocks takes 8 * 2 * 80 ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The method for generating the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0467] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Community physical ID.

[0468] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0469] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the remaining 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted four times to provide the final 2 bits. Four NPBCH sequences are mapped to subframe positions #0, #1, #2, and #3 of the radio frame used for downlink transmission within 80ms. Transmitting one NPBCH block four times requires 1*80ms, and transmitting all eight NPBCH blocks requires 8*1*80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0470] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Community physical ID.

[0471] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0472] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 6 bits, the remaining 4 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block needs to be transmitted twice to provide 1 bit. The subframe positions #0, #1, #2, and #3 of the radio frames used for downlink transmission within 80ms are mapped to four NPBCH sequences. Transmitting all eight NPBCH blocks takes 4 * 1 * 80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0473] Where n p Indicates the subframe number. Community physical ID.

[0474] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0475] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 7 bits, the remaining 3 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block needs to be transmitted once. The subframe positions #0, #1, #2, and #3 of the radio frames used for downlink transmission within 80ms are mapped to four NPBCH sequences. Transmitting all eight NPBCH blocks takes 2 * 80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0476] in Indicates the community ID.

[0477] In the satellite communication method described above, the first information in step S100 includes several frame structure pattern information in TDD mode. One period of the first TDD frame structure in TDD mode includes N (e.g., 8) radio frames, meaning the period of the first TDD frame structure is 80ms. One period of the first TDD frame structure includes two radio frames used for downlink transmission. Furthermore, the first signal in step S200 includes NPBCH, the content of which is as described above and will not be repeated here.

[0478] In embodiments of this disclosure, as shown in FIG30, each radio frame for downlink transmission includes a preset subframe for transmitting an NPBCH sequence, and the configuration method of the NPBCH frame structure pattern information includes at least one of the following:

[0479] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0480] For example, the same NPBCH block is transmitted once on subframe #0 of two radio frames used for downlink transmission. Each retransmission applies a different scrambling sequence. Transmitting one NPBCH block takes 4*80ms, and transmitting 8 NPBCH blocks takes 8*4*80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, wherein the initialization of the mask sequence is determined based on at least one of the following formulas:

[0481] Case 1: Starting with an odd-numbered frame, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0482] Where, n f Indicates the wireless frame number. Indicates the community ID.

[0483] Case 2: Starting from an even-numbered frame, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0484] Where, n f Indicates the wireless frame number. Indicates the community ID.

[0485] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0486] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the remaining 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted four times to provide the final 2 bits. An NPBCH sequence is mapped starting at subframe position #0 of two radio frames used for downlink transmission. Transmitting the same NPBCH block four times takes 2 * 80 ms, and transmitting all eight NPBCH blocks takes 8 * 2 * 80 ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on at least one of the following formulas:

[0487] Case 1: Starting with an odd-numbered frame, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0488] Where n f Indicates the wireless frame number. Indicates the community ID.

[0489] Case 2: Starting from an even-numbered frame, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0490] Where n f Indicates the wireless frame number. Indicates the community ID.

[0491] MasterInformationBlock-NB::=SEQUENCE{

[0492] systemFrameNumber-MSB-r13 BIT STRING(SIZE(5)),

[0493] hyperSFN-LSB-r13 BIT STRING(SIZE(2)),

[0494] schedulingInfoSIB1-r13 INTEGER(0..15),

[0495] systemInfoValueTag-r13 INTEGER(0..31),

[0496] ab-Enabled-r13 BOOLEAN,

[0497] operationModeInfo-r13 CHOICE{

[0498] inband-SamePCI-r13 Inband-SamePCI-NB-r13,

[0499] inband-DifferentPCI-r13 Inband-DifferentPCI-NB-r13,

[0500] guardband-r13 Guardband-NB-r13,

[0501] standalone-r13 Standalone-NB-r13

[0502] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0503] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 6 bits, the remaining 4 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted twice to provide the final 1 bit. One NPBCH sequence is mapped at subframe position #0 of two radio frames used for downlink transmission. Transmitting the same NPBCH block twice takes 80ms, and transmitting all eight NPBCH blocks takes 8 * 1 * 80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on at least one of the following formulas:

[0504] Case 1: Starting with an odd-numbered frame, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0505] Where n f Indicates the wireless frame number. Indicates the community ID.

[0506] Case 2: Starting from an even-numbered frame, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0507] Where n f Indicates the wireless frame number. Indicates the community ID.

[0508] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0509] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 7 bits, the remaining 3 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted once. One NPBCH sequence is mapped at subframe position #0 of two radio frames used for downlink transmission. Transmitting all eight NPBCH blocks takes 4 * 1 * 80 ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0510] in, Indicates the community ID.

[0511] In embodiments of this disclosure, as shown in FIG31, each radio frame for downlink transmission includes two preset subframes for transmitting NPBCH sequences, and the configuration of the NPBCH frame structure pattern information includes at least one of the following:

[0512] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0513] For example, the same NPBCH block is repeatedly transmitted twice on subframes #0 and #1 of a radio frame used for downlink transmission, with a different scrambling sequence applied each time. Transmitting one NPBCH block takes 2*80ms, and transmitting 8 NPBCH blocks takes 8*2*80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, wherein the mask sequence initialization is determined based on at least one of the following formulas:

[0514] Case 1: Starting with an odd-numbered frame, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0515] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the community ID.

[0516] Case 2: Starting from an even-numbered frame, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0517] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the community ID.

[0518] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0519] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the remaining 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted four times to provide the final 2 bits. Two NPBCH sequences are mapped at subframe positions #0 and #1 of two radio frames used for downlink transmission. Transmitting the same NPBCH block four times takes 80ms, and transmitting all eight NPBCH blocks takes 8*1*80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on at least one of the following formulas:

[0520] Case 1: Starting with an odd-numbered frame, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0521] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the community ID.

[0522] Case 2: Starting from an even-numbered frame, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0523] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the community ID.

[0524] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0525] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 6 bits, the remaining 4 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted twice to provide the final 1 bit. Two NPBCH sequences are mapped at subframe positions #0 and #1 of two radio frames used for downlink transmission. Two NPBCH blocks are transmitted within an 80ms period, and transmitting all eight NPBCH blocks takes 4 * 80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0526] Where n p Indicates the subframe number. Community physical ID.

[0527] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0528] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 7 bits, the remaining 3 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted once. Two NPBCH sequences are mapped at subframe positions #0 and #1 of two radio frames used for downlink transmission. Four NPBCH blocks are transmitted within an 80ms period, and transmitting all eight NPBCH blocks takes 2 * 80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0529] in, Indicates the community ID.

[0530] In embodiments of this disclosure, as shown in FIG32, each radio frame for downlink transmission includes four preset subframes for transmitting NPBCH sequences, and the configuration of the NPBCH frame structure pattern information includes at least one of the following:

[0531] Method 1: The bit value is the first bit value (4 bits), which means that each NPBCH original sequence is transmitted repeatedly eight times; 64 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0532] For example, the same NPBCH block is repeatedly transmitted four times on subframes #0, #1, #2, and #3 of a radio frame used for downlink transmission. Transmitting one NPBCH block takes a period of 1*80ms. Each NPBCH block transmitted within this period contains the same content but is equipped with a different scrambling sequence. Transmitting eight NPBCH blocks takes 8*1*80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on at least one of the following formulas:

[0533] Case 1: Starting with an odd-numbered frame, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0534] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the community ID.

[0535] Case 2: Starting from an even-numbered frame, two consecutive radio frames for downlink transmission are activated. The mask sequence initialization is determined based on the following formula:

[0536] Where n f Indicates the wireless frame number, n p Indicates the subframe number. Indicates the community ID.

[0537] Method 2: The bit value is the second bit value (5 bits), that is, each NPBCH original sequence is transmitted four times; 32 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0538] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 5 bits, the remaining 5 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted four times to provide the final 2 bits. Four NPBCH sequences are mapped at subframe positions #0, #1, #2, and #3 of the radio frame used for downlink transmission. Two NPBCH blocks can be mapped within an 80ms period. Transmitting all eight NPBCH blocks takes 4 * 1 * 80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0539] Where n p Indicates the subframe number. Indicates the community ID.

[0540] Method 3: The bit value is the third bit value (6 bits), which means that each NPBCH original sequence is transmitted twice; 16 different NPBCH sequences are sequentially mapped between the preset subframe positions used to transmit NPBCH sequences.

[0541] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 6 bits, the remaining 4 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted twice to provide the final 1 bit. Four NPBCH sequences are mapped at subframe positions #0, #1, #2, and #3 of the radio frame used for downlink transmission. Four NPBCH blocks can be mapped within an 80ms period. Transmitting all eight NPBCH blocks takes 2 * 1 * 80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0542] Where, n p Indicates the subframe number. Indicates the community ID.

[0543] Method 4: The bit value is the fourth bit value (7 bits), that is, each NPBCH original sequence is transmitted once; 8 different NPBCH sequences are sequentially and cyclically mapped between the preset subframe positions used to transmit NPBCH sequences.

[0544] For example, when the high-order bits used to indicate frame information in the MIB-NB are configured to be 7 bits, the remaining 3 bits of frame information are implicitly indicated by decoding the NPBCH. Eight NPBCH blocks require 3 bits, and each NPBCH block is transmitted once. Four NPBCH sequences are mapped at subframe positions #0, #1, #2, and #3 of the radio frame used for downlink transmission. Eight NPBCH blocks can be mapped within an 80ms period, and transmitting all eight NPBCH blocks takes 1*80ms. The generation of the NPBCH sequence is related to the original NPBCH sequence and the mask sequence. The generation method of the NPBCH sequence refers to protocol TS 36.211, where the mask sequence initialization is determined based on the following formula:

[0545] in, Indicates the community ID.

[0546] Figure 33 illustrates one of the flowcharts of a satellite communication method in Time Division Duplex (TDD) mode provided in this disclosure. As shown in Figure 33, the satellite communication method further includes step S300: UE120 receives second information sent by base station 110. The second information includes at least one of the following: system message or frame configuration information. The frame configuration information includes at least one of the following: radio frame number and frame pattern corresponding to different frame numbers, activated uplink / downlink frame structure, activated reference point information, downlink to uplink guard interval, activated uplink / downlink duration, random access response (RAR) window and contention resolution window. The frame configuration information can be sent through at least one of system message, RRC, DCI, or MAC CE, and is used for frame structure update in initial access or RRC connection state. For example, the system message can be at least one of MIB-NB, System Information Block 1 (SIB1), or other system messages besides SIB1 (e.g., System Information Block 31 (SIB31)). The frame pattern corresponding to different frame numbers can be the frame pattern information corresponding to different radio frame numbers. The activation reference point information is based on the acquired frame information and can be aligned with frame #0 or offset from frame #0 by a fixed frame or subframe. The offset value can be indicated by predefined methods, RRC, Downlink Control Information (DCI), or MAC CE. The unit of the offset value can be a radio frame, a subframe, or milliseconds (ms). The activation duration of uplink and downlink is the activation duration of uplink and downlink. After receiving the first signal, UE120 can decode the NPBCH narrowband master information block (MIB-NB) contained in the first signal and / or the system message can obtain the subsequently updated TDD frame structure. Base station 110 sends frame configuration information to UE 120, so that base station 110 can configure flexible frame structure for UE 120 according to actual service requirements.

[0547] In embodiments of this disclosure, the satellite communication method further includes: determining an update frame structure based on at least one of the system message, RRC, MAC CE, and / or DCI. The configuration of the update frame structure includes at least one of the following:

[0548] The number of radio frames is configured in at least one of the system messages, RRC, MAC CE and / or DCI, and the number of radio frames corresponds to a fixed frame pattern;

[0549] The number of radio frames is configured in at least one of the system messages, RRC, MAC CE and / or DCI, and there is a mapping relationship between the number of radio frames and the frame pattern;

[0550] A predefined number of wireless frames is configured with an index in at least one of the system messages, RRC, MAC CE, and / or DCI, wherein the index is used to indicate the frame pattern;

[0551] or,

[0552] Configure at least one of the following parameters in at least one of the system messages, RRC, MAC CE and / or DCI: number of radio frames, number of downlink transmission frames or subframes, number of guard interval frames or subframes, and number of uplink transmission frames or subframes.

[0553] Specifically, after receiving the synchronization signal and completing downlink synchronization of NPSS and NSSS, UE120 can flexibly configure the frame structure according to its needs.

[0554] For example, at least one of the following methods can be used:

[0555] Method 1: Configure the number of radio frames (frameNumber) in MIB-NB, SIB1, RRC, DCI, or MAC CE. Each radio frame number is associated with a fixed pattern type. For example, as shown in Table 1, the number of radio frames can be configured to 8 or 9. For example, in the TDD-based frame structure design (D+G+U), D represents the number of downlink subframes, G represents the number of guard interval subframes, and U represents the number of uplink subframes. When the number of radio frames is configured to 9, the associated frame structure is (10, 70, 10); when the number of radio frames is configured to 8, the associated frame structure is (20, 40, 20).

[0556] Table 1: Frame Structure of Wireless Frames

[0557] Method 2: A TDD-based frame structure design (D+G+U) is used, where D represents the number of downlink subframes, G represents the number of guard interval subframes, and U represents the number of uplink subframes. The `frameNumber` parameter is configured in the MIB-NB, SIB1, RRC, DCI, or MAC CE to indicate the number of radio frames. There is a mapping relationship between the number of radio frames and the frame pattern. For example, the number of radio frames can be configured to 8 or 9. Each radio frame number corresponds to a frame pattern (such as a frame structure table). A frame index `frameindex` is configured to indicate the corresponding frame structure type. When the number of radio frames is 9, as shown in Table 2, the configurable types include (8, 74, 8), (10, 70, 10), (20, 50, 20), (30, 30, 30), (40, 30, 20), (45, 30, 15), (50, 30, 10), and (34, 22, 24), corresponding to frame indices 0-7 when the number of radio frames is 8. When the number of wireless frames is 8, as shown in Table 3, the configurable types include (8, 64, 8), (10, 60, 10), (15, 50, 15), (20, 40, 20), (25, 30, 25), (30, 30, 20), (40, 30, 10), and (29, 22, 29), which correspond to the frame indices 0-7 when the number of wireless frames is 8.

[0558] Table 2. Frame-configurable structure when the number of wireless frames is 9.

[0559] Table 3. Frame-configurable structure when the number of wireless frames is 8.

[0560] Method 3: Predefine the number of wireless frames, that is, the number of wireless frames is fixed. Configure the frame information index frameindex in MIB-NB, SIB1, RRC, DCI, or MAC CE. The frame information index frameindex is used to indicate the specific frame structure type. For the mapping relationship between frame structure field indices, refer to Method 2 above.

[0561] Method 4: TDD-based frame structure design (D+G+U), where D represents the number of downlink subframes, G represents the number of guard interval subframes, and U represents the number of uplink subframes. Configure at least one of the following parameters in the MIB-NB, system message, RRC, DCI, or MAC CE: number of radio frames, number of downlink transmission frames or subframes, number of guard interval frames or subframes, and number of uplink transmission frames or subframes. Specifically, configure the parameter `frameNumber` in the MIB-NB or SIB1 to indicate the number of radio frames, which can be configured as 8 or 9. Alternatively, the parameters `framedownlink` and `frameguard` can be configured to indicate the number of downlink and guard interval subframes, respectively. The uplink subframes can be implicitly calculated since the total number of radio frames is known.

[0562] As previously stated, step S300 involves receiving second information, which may include frame configuration information. The configuration information may include activating the uplink and downlink frame structure. The activation of the uplink and downlink frame structure will now be further explained.

[0563] In embodiments of this disclosure, the configuration method for activating the uplink and downlink frame structure includes at least one of the following:

[0564] Configure and activate downlink start position information, downlink duration, protection interval duration, and uplink duration;

[0565] Configure and activate downlink start position information, protection interval start position information, protection interval duration, and uplink duration;

[0566] Configure the activation start position information for downlink, the activation end position information for uplink, the duration of downlink, and the duration of the protection interval;

[0567] Configure the activation of uplink start position information, activation of downlink start position information, uplink duration, downlink duration, and protection interval duration;

[0568] Configure the activation of downlink start position information, downlink duration, and protection interval duration;

[0569] or,

[0570] Configure the start position of the activation cycle, as well as the activation uplink start position information, the uplink duration, and the downlink duration.

[0571] Specifically, after completing downlink synchronization, UE120 continues to decode the NPBCH to obtain system frame information and obtains other system messages by decoding the SIB1-NB. Therefore, relevant parameters can be configured in the MIB-NB, SIB1-NB, SIBX-NB, RRC, DCI, or MAC CE to activate the uplink / downlink structure, as shown in Figure 34. The configuration method for activating the uplink / downlink structure adopts at least one of the following:

[0572] Method 1: The configuration parameter `framenumber` indicates the entire active uplink and downlink transmission period, using the start position of radio frame X as a reference point. The configuration offset value `active_downlink_offsett` indicates the offset between the active downlink start position and the reference point to determine the start position of the active downlink; the unit can be ms or subframes. The configuration length parameters `active_downlinksize`, `guardsize`, and `active_uplinksize` indicate the duration of the active downlink, the duration of the guard interval, and the duration of the active uplink, in ms or subframes. For example: When the radio frame number is 9, the number of active downlink subframes is 8, and mapping starts from subframe #4 of frame 0, the number of active uplink subframes is also 8, then the number of guard interval subframes is 74. Therefore, `framenumber` is 9, occupying 4 bits; `active_downlink_offsett` is 4, occupying 2 bits; and the parameters `active_downlinksize`, `guardsize`, and `active_uplinksize` are 8, 74, and 8 respectively, occupying 3, 7, and 3 bits respectively, for a total of 19 bits.

[0573] Method 2: The configuration parameter `framenumber` indicates the entire active uplink and downlink transmission period. Using the start position of radio frame X as a reference point, the configuration offset values ​​`active_downlink_offsett` and `guard_offset` indicate the offset between the active downlink start position and the reference point to determine the start position of the active downlink and guard interval. The configuration length parameters `guardsize` and `active_uplinksize` indicate the duration of the guard interval and active uplink, in milliseconds or subframes. For example: When the radio frame number is 9, the number of active downlink subframes is 8, and mapping starts from subframe #4 of frame 0, the number of active uplink subframes is also 8, then the number of guard interval subframes is 74. Therefore, `framenumber` is 9, occupying 4 bits; `active_downlink_offsett` and `guard_offset` are 4 and 12 respectively, occupying 2 and 4 bits respectively; and the parameters `guardsize` and `active_uplinksize` are 74 and 8 respectively, occupying 7 and 3 bits respectively, for a total of 20 bits.

[0574] Method 3: The configuration parameter `framenumber` indicates the entire active uplink and downlink transmission period, using the start position of radio frame X as a reference point. The configuration offset value `active_downlink_offsett` indicates the offset between the start position of the active downlink and the reference point to determine the start position of the active downlink. The unit can be ms or subframes. The configuration length parameters `active_downlinksize` and `guardsize` indicate the duration of the active downlink and guard intervals, and the configuration parameter `active_uplink_offsett` indicates the end time of the active uplink, in ms or subframes. For example: when the number of radio frames is 9, the number of active downlink subframes is 8, and mapping starts from subframe #4 of frame 0, the number of active uplink subframes is also 8, then the number of guard interval subframes is 74. Therefore, `framenumber` is 9, occupying 4 bits; `active_downlink_offsett` is 4, occupying 2 bits; `active_downlinksize` and `guardsize` are 8 and 74 respectively, occupying 3 and 7 bits respectively; and `active_uplink_offsett` is 94, occupying 7 bits, for a total of 23 bits.

[0575] Method 4: The configuration parameter `framenumber` indicates the entire active uplink and downlink transmission period. Using the start position of radio frame X as a reference point, the configuration offset values ​​`active_downlink_offset` and `active_uplink_offset` indicate the offset values ​​between the active downlink and active uplink and the start position and reference point, respectively, to determine the start position of the active downlink and active uplink. The unit can be milliseconds (ms) or subframes. The configuration length parameters `active_downlinksize`, `guardsize`, and `active_uplinksize` indicate the duration of the active downlink, guard interval, and active uplink, respectively, in milliseconds or subframes. For example: when the radio frame number is 9, the number of active downlink subframes is 8, and mapping starts from subframe #4 of frame 0, the number of active uplink subframes is also 8, then the number of guard interval subframes is 74. Therefore, the framenumber is 9, occupying 4 bits; the active_downlink_offsett and active_uplink_offset values ​​are 4 and 86, occupying 2 and 8 bits respectively; the parameters active_downlinksize and guardsize are 8 and 74, occupying 3 and 7 bits respectively; and the active_downlink_offsett value is 86, occupying 7 bits, for a total of 31 bits.

[0576] Method 5: When the duration of active uplink and downlink is the same, the configuration parameter `framenumber` indicates the entire period of active uplink and downlink transmission. Using the start position of radio frame X as a reference point, the configuration offset value `active_downlink_offsett` indicates the offset between the start position of active downlink and the reference point to determine the start position of active downlink. The unit can be ms or subframes. The configuration length parameters `active_downlinksize` and `guardsize` indicate the active downlink and guard interval, in ms or subframes. For example: When the number of radio frames is 9, the number of active downlink subframes is 8, and mapping starts from subframe #4 of frame 0, the number of active uplink subframes is also 8, then the number of guard interval subframes is 74. Therefore, `framenumber` is 9, occupying 4 bits; `active_downlink_offsett` is 4, occupying 2 bits; and the parameters `active_downlinksize`, `guardsize`, and `guardsize` are 8, 72, and 8 respectively, occupying 3 and 7 bits respectively, for a total of 16 bits.

[0577] Method Six: When the duration of active uplink and downlink is the same, the configuration parameter `framenumber` indicates the entire period of active uplink and downlink transmission, using the starting position of radio frame X as the reference point. The configuration offset value `active_downlink_offsett` indicates the position relative to the reference point within the entire 90ms period, in milliseconds or subframes. The configuration offset value `active_uplink_offset` indicates the position of active uplink within the 90ms period. The configuration length parameters `active_downlinksize` and `active_downlinksize` indicate the duration of active uplink and downlink, in milliseconds or subframes. For example: When the number of radio frames is 9, the number of active downlink subframes is 8, and mapping starts from subframe #4 of frame 0, the number of active uplink subframes is also 8, then the number of subframes in the guard interval is 74. Therefore, `framenumber` is 9, occupying 4 bits; `active_downlink_offsett` is 4, occupying 2 bits; `active_active_offsett` is 82, occupying 7 bits; and the parameters `active_downlinksize` and `active_downlinksize` are 8 and 8 respectively, occupying 3 and 3 bits respectively, for a total of 19 bits.

[0578] As previously stated, step S300 involves receiving second information, which may include frame configuration information, and the configuration information may include a RAR window. The RAR window will now be further explained.

[0579] In embodiments of this disclosure, as shown in FIG35, the configuration of the RAR window includes:

[0580] Based on the first TDD frame structure, an offset value based on a first reference time point is configured, wherein the first reference time point is the time point when the RAR window opens or the time point when the RAR window closes.

[0581] or,

[0582] In TDD mode, the RAR window starts at the subframe where the last NRPACH repetition occurs, and the length of the RAR window is X subframes plus the round-trip communication delay between the two nodes, where X is associated with the structure of the first TDD frame.

[0583] Specifically, to prevent the RAR window from falling within the guard interval or uplink subframe range, at least one of the following methods is adopted:

[0584] Method 1: Configure offset values ​​to determine the starting point or window size of the RAR window;

[0585] The RAR window size remains unchanged: Based on the determined first TDD frame structure (legacy TDD frame structure), an offset value ra-window_offset is configured to indicate either the offset value indicating the opening time of the RAR window or the offset value indicating the ending time of the RAR window. The ra-window_offset value is determined based on the number of cycles and uplink subframes of the TDD frame structure pattern. For example, for a (D, G, U) frame structure, where D represents the number of downlink subframes, G represents the guard interval, and U represents the number of uplink subframes, under a (10, 70, 10) configuration, at LEO-600, the maximum RTT is 25.77ms. The offset value should be configured to be at least 96 - RTT - RAR - ra_ResponseWindowSize to indicate the ending time of the RAR window, or at least 86 - RTT to indicate the ending time of the RAR window. The offset value can be indicated using one of the following methods:

[0586] 1. Configure the offset parameter ra-window_offset in SIB2. The unit can be ms, s, subframes, or radio frames;

[0587] RACH-Info-NB-r13::=SEQUENCE{

[0588] ra-ResponseWindowSize-r13 ENUMERATED{pp2,pp3,pp4,pp5,pp6,pp7,pp8,pp10},

[0589] ra-window_offset INTER{0...N}

[0590] mac-ContentionResolutionTimer-r13 ENUMERATED{pp1,pp2,pp3,pp4,pp8,pp16,pp32,pp64}

[0591] }

[0592] 2. If the offset value N is configured via DCI or MAC-CE, the bit size occupied is ceil(log2(N));

[0593] Method 2: Define the rules;

[0594] In TDD mode, the random access response window (RAR) starts from the subframe containing the last preamble sequence repetition. That is, the RAR starts from the subframe containing the last NPRACH repetition, then adds X subframes and the round-trip time (RTT) of two nodes (e.g., UE-base station 110). The value of X is associated with the first TDD frame structure. X = 90 - RTT to satisfy one cycle, ensuring the RAR window starts on an available radio frame for downlink transmission, or X = 90 + U - ra_ResponseWindowSize, where U represents the number of uplink subframes, ensuring the RAR window ends within a downlink frame. For example, in a TDD-based frame structure design (D+G+U), D represents the number of downlink subframes, G represents the number of guard interval subframes, and U represents the number of uplink subframes. For LEO-600, the maximum RTT is 25.77ms. Given a defined frame structure type (10, 70, 10), RTT + X needs to cover the next cycle to ensure the RAR start window falls within available downlink resources. X is 64, representing a unit subframe.

[0595] Alternatively, in TDD mode, the start time of the RAR window can be postponed to the nearest available downlink frame. This could be the first subframe after the start of the downlink frame, the last subframe after the last uplink frame before the downlink frame, or the last subframe after the last guard interval after the downlink frame.

[0596] As previously stated, step S300 involves receiving second information, which may include frame configuration information, and the frame configuration information may include a contention resolution window. The contention resolution window will now be further explained.

[0597] In embodiments of this disclosure, the configuration of the contention resolution window includes:

[0598] Based on the first TDD frame structure, an offset value based on a second reference time point is configured, wherein the second reference time point is the time point when the contention resolution window opens or the time point when the contention resolution window closes;

[0599] or,

[0600] In TDD mode, the start time of the contention resolution timer is delayed until the next available downlink frame.

[0601] Specifically, the configuration of the contention resolution window includes at least one of the following:

[0602] Method 1: Configure offset values ​​to determine the starting point or size of the window;

[0603] Based on the determined first TDD frame structure, an offset value `con-window_offset` is configured to indicate either the offset value at the start time of the contention resolution window or the offset value at the end time of the contention resolution window. The `con-window_offset` value is determined based on the number of cycles and the number of uplink subframes in the TDD frame structure pattern. For example, for a (D, G, U) frame structure, where D represents the number of downlink subframes, G represents the guard interval, and U represents the number of uplink subframes, under a (10, 70, 10) configuration, at LEO-600, the maximum RTT is 25.77 ms. The offset value should be configured with at least 100 `mac-ContentionResolutionTimer` to indicate the end time of the contention resolution timer, or at least 90 `RTT` to indicate the end time of the RAR window. The offset value can be indicated using at least one of the following methods:

[0604] Method 1: Configure the offset parameter con-window_offset in SIB2. The unit can be ms, s, subframes, or radio frames.

[0605] RACH-Info-NB-r13::=SEQUENCE{

[0606] ra-ResponseWindowSize-r13 ENUMERATED{pp2,pp3,pp4,pp5,pp6,pp7,pp8,pp10},

[0607] Con-window_offset INTER{0...N}

[0608] mac-ContentionResolutionTimer-r13 ENUMERATED{pp1,pp2,pp3,pp4,pp8,pp16,pp32,pp64}

[0609] }

[0610] Method 2: Configure the offset value N via DCI or MAC-CE, then the bit size occupied is ceil(log2(N)).

[0611] Method 2: Define Rules

[0612] In TDD mode, the start time of the contention resolution timer is delayed until the next available downlink frame. This can be the first subframe of the downlink frame, the last subframe of the uplink frame before the downlink frame, or the last subframe of the guard interval after the downlink frame.

[0613] Alternatively, in TDD mode, after sending Msg3-NPUSCH, add X subframes to enable the contention resolution window. The X value is associated with the uplink and downlink position information in the first TDD frame structure to ensure that the contention resolution timer starts on an available downlink frame.

[0614] As shown in Figure 33, the satellite communication method further includes step S400: determining at least one of the following configurations: Narrowband Physical Random Access Channel (NPRACH) configuration or transmission rules, Random Access Response (RAR) window configuration, or Contention Resolution Window configuration.

[0615] It is worth noting that the RAR window configuration is the same as the RAR window configuration method described above, and the contention resolution window configuration is the same as the contention resolution window configuration method described above. If base station 110 configures RAR window configuration and / or contention resolution window configuration for UE 120, then UE 120 does not need to predefine RAR window configuration and / or contention resolution window configuration. If base station 110 does not configure RAR window configuration and / or contention resolution window configuration for UE 120, then a possible approach is to predefine RAR window configuration and / or contention resolution window configuration on both base station 110 and UE 120, so that base station 110 and UE 120 can reach a consensus.

[0616] In addition to sending the aforementioned RAR window configuration and / or contention resolution window configuration to UE120, base station 110 can also send Narrowband Physical Random Access Channel (NPRACH) configuration or transmission rules.

[0617] In embodiments of this disclosure, the NPRACH configuration or transmission rules include:

[0618] Configure the NPRACH period in the system information, and the period is associated with the period parameter of the radio frame;

[0619] or,

[0620] The NPRACH transmission timing is located within the guard interval or downlink frame, and the NPRACH is transmitted starting from the first subframe of the uplink resource closest to the random access channel timing RO;

[0621] or,

[0622] NPRACH is sent only when the RO is in an available uplink resource.

[0623] Specifically, to ensure sufficient access opportunities for NPRACH, at least one of the following methods is adopted:

[0624] Method 1: Configure the NPRACH period in the system information (such as SIB2) and associate the NPRACH period with the period parameters of the radio frame. For example, when the period of the frame structure is 90ms, add period parameters ms90 and ms180 to the parameter nprach-Periodicity-r13; when the period of the frame structure is 80ms, add period parameters ms80 and ms160 to the parameter nprach-Periodicity-r13.

[0625] NPRACH-Parameters-NB-r13::=SEQUENCE{

[0626] nprach-Periodicity-r13 ENUMERATED{ms40,ms80,ms160,ms240,ms320,ms640,ms1280,ms2560,ms90,ms180},

[0627] nprach-StartTime-r13 ENUMERATED{ms8,ms16,ms32,ms64,ms128,ms256,ms512,ms1024},

[0628] nprach-SubcarrierOffset-r13 ENUMERATED{n0,n12,n24,n36,n2,n18,n34,spare1},

[0629] ...

[0630] }

[0631] Method 2: When UE120 sends NPRACH, it can do so within the guard interval or downlink frame. UE120 can start sending NPRACH from the first subframe of the uplink resource closest to RO, as shown in Figure 36.

[0632] Method 3: If the RO falls on a non-uplink subframe, discard the current RO and do not send NPRACH.

[0633] Method 4: Determine the location of overlapping uplink resources based on the frame structure period and NPRACH period, and only send NPACH on the overlapping uplink resources. The period of the overlapping resources is determined based on the least common multiple of the NPRACH and frame periods. For example, when the NPACH period is configured to be 40ms and the frame structure period is 90ms, an overlap occurs every 360ms. UE120 is limited to sending NPRACH only at these overlapping locations.

[0634] As shown in Figure 33, the satellite communication method further includes the following steps:

[0635] S500: UE120 sends third information to base station 110, wherein the third information includes a preamble;

[0636] S600: UE120 starts listening to RAR based on the available downlink resource location information in the first TDD frame structure. The available downlink resource location information includes at least one of the following: TDD frame structure pattern information, the length of the RAR window, or the offset value.

[0637] As shown in Figure 33, the satellite communication method further includes the following steps:

[0638] S700: UE120 receives RAR, also known as MSG2, from base station 110.

[0639] As shown in Figure 33, the satellite communication method further includes the following steps:

[0640] S800: UE120 sends a fourth message to base station 110. The fourth message is used to request connection establishment. The fourth message is also known as MSG3.

[0641] S900: UE120 starts listening for contention resolution based on the available downlink resource location information in the first TDD frame structure. The available downlink resource location information includes at least one of the following: TDD frame structure pattern information, the length of the contention resolution window, or an offset value.

[0642] As shown in Figure 33, the satellite communication method further includes the following steps:

[0643] S1000: Contention resolution for UE120 receiving data from base station 110, also known as MSG4.

[0644] S1100: UE120 sends an acknowledgment (ACK) message to base station 110.

[0645] It is worth noting that the satellite communication method can perform at least one of the steps in Figure 33, and the order of execution of the steps in Figure 33 is not limited.

[0646] This document describes satellite communication methods applicable to communication between a UE and a base station, as well as communication between the core network and the base station. However, these inventive concepts, methods, apparatuses, devices, computer-readable storage media, chips, and computer program products are not limited and can be extended to other communication scenarios to achieve the same technical benefits and effects.

[0647] In these scalable communication scenarios, a User Equipment (UE) refers to a device used for communication at the user end, such as a mobile phone, and can also be called a terminal, mobile station, or mobile terminal. A UE can be a variety of devices, including but not limited to mobile phones, tablets, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals for industrial control, wireless terminals for autonomous driving, wireless terminals for remote medical surgery, wireless terminals for smart grids, wireless terminals for environmental monitoring, wireless terminals for smart cities, and wireless terminals for smart homes, etc.

[0648] Furthermore, UEs and base stations can be deployed in various environments, including but not limited to indoor, outdoor, handheld devices, vehicle-mounted devices, or even on water, in the air, on airplanes, drones, or on satellites.

[0649] Therefore, although this document describes methods and devices for satellite communication, the inventive concepts and techniques contained herein can be extended to other communication scenarios and are expected to achieve the same technical benefits and effects. It is readily apparent that these inventive concepts have broad applicability and scalability, whether for communication between different types of base stations and user equipment, or for communication in different deployment environments.

[0650] It should be noted that the above steps are merely examples and do not limit the scope of the invention. Various modifications and variations can be made to the steps without departing from the spirit and scope of the invention.

[0651] The order of the described steps (signaling / boxes) is not intended to be construed as a limitation, and any number of the described steps (signaling / boxes) can be skipped or combined in any order to implement the method or an alternative method.

[0652] This disclosure describes examples of communication between terminals and network element components in the network architecture described in the above embodiments, which are primarily for illustrative purposes and not for limitation.

[0653] The order of the described steps (signaling / blocks) is not intended to be construed as limiting, and any number of the described steps (signaling / blocks) can be skipped or combined in any order to implement the method or alternative methods. Generally, any of the components, modules, methods, and operations described herein can be implemented using software, firmware, hardware (e.g., fixed logic circuitry), manual processing, or any combination thereof. Some operations of the example methods can be described in the general context of executable instructions stored on computer-readable storage located locally and / or remotely on a computer processing system, and implementations can include software applications, programs, functions, etc. Alternatively or additionally, any functionality described herein can be performed at least in part by one or more hardware logic components, such as, but not limited to, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), system-on-a-chip (SoCs), complex programmable logic devices (CPLDs), etc.

[0654] Furthermore, the signaling transmission described in the embodiments of this disclosure can be implemented in any manner known in the art. For example, signaling transmission can be explicit and / or implicit. Moreover, the illustrated steps (signaling / blocks) are for illustrative purposes only and are not intended to limit this application.

[0655] Figure 37 is a schematic structural diagram of a wireless communication device 900 provided in this disclosure. The wireless communication device includes a processor and a memory, the memory for storing computer programs, and the processor for calling and running the computer programs stored in the memory to execute the instructions described above.

[0656] The wireless communication device can be a user equipment, a base station, or a network element. The wireless communication device 900 shown in Figure 37 includes a processor 910, which can call and run computer programs from memory to implement the methods in the embodiments of this application.

[0657] Optionally, as shown in FIG37, the wireless communication device 900 may further include a memory 920. The processor 910 can call and run computer programs from the memory 920 to implement the methods in the embodiments of this application. The memory 920 may be a separate device independent of the processor 910, or it may be integrated into the processor 910.

[0658] Optionally, as shown in FIG37, the wireless communication device 900 may further include a transceiver 930, which the processor 910 may control to communicate with other devices. Specifically, it may send information or data to other devices or receive information or data sent by other devices. The transceiver 930 may include a transmitter and a receiver. The transceiver 930 may further include an antenna, and the number of antennas may be one or more.

[0659] Optionally, the wireless communication device 900 may specifically be a base station in the embodiments of this application, and the wireless communication device 900 may implement the corresponding processes implemented by the base station in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0660] Optionally, the wireless communication device 900 may specifically be a mobile user equipment / user equipment in the embodiments of this application, and the wireless communication device 900 may implement the corresponding processes implemented by the mobile user equipment / user equipment in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0661] Optionally, the wireless communication device 900 may specifically be a network element in the embodiments of this application, and the wireless communication device 900 may implement the corresponding processes implemented by the network element in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0662] According to an example embodiment, a chip is provided, the chip including: a processor for calling and running a computer program from a memory, causing a device on which the chip is installed to perform the method according to any one of the above embodiments, examples, or example embodiments.

[0663] According to an example embodiment, a computer-readable storage medium is provided for storing a computer program that causes a computer to perform a method according to any one of the above embodiments, examples, or example embodiments.

[0664] According to an example embodiment, a computer program product is provided, including a computer program / instructions that, when executed by a processor (e.g., by the processor or an apparatus, device, computer, or machine including the processor), implement the method according to any one of the above embodiments, examples, or example embodiments.

[0665] Embodiments of this disclosure are combinations of technologies / processes that can be employed in 3GPP specifications to create a final product.

[0666] While this disclosure has been described in conjunction with what are considered to be the most practical and preferred embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments, but is intended to cover various arrangements made without departing from the broadest interpretation of the appended claims.

Claims

1. A satellite communication method in Time Division Duplex (TDD) mode, executed on a user equipment, the satellite communication method comprising: The first information is determined; wherein the first information includes at least one of the following: narrowband secondary synchronization signal (NSSS) frame structure pattern information and narrowband physical broadcast channel (NPBCH) frame structure pattern information; wherein the NSSS frame structure pattern information is the pattern information of NSSS in time division duplex (TDD) mode, the NPBCH frame structure pattern information is the pattern information of NPBCH in TDD mode, the first period of the first TDD frame structure in TDD mode is a first value or a second value, and the configuration method of the NPBCH frame structure pattern information includes at least one of the following: the original NPBCH sequence is repeatedly transmitted between subframes and / or between radio frames, or the number of repetitions of the original NPBCH sequence is reduced based on the bit value of the most significant bit (MSB) in the narrowband main information block (MIB-NB); Based on the first information, a first signal is received, wherein the first signal is a downlink synchronization signal, and the first signal includes at least one of the following: the NSSS, the NPBCH, or the narrowband primary synchronization signal NPSS.

2. The method according to claim 1, wherein, The satellite communication method also includes: Receive second information, the second information including at least one of the following: system message, or frame configuration information, wherein the frame configuration information includes at least one of the following: wireless frame number and frame pattern corresponding to different frame numbers, activated uplink and downlink frame structure, activated reference point information, protection interval for downlink to uplink handover, duration of activated uplink and downlink, random access response (RAR) window and contention resolution window.

3. The method according to claim 1, wherein, The satellite communication method also includes: Determine at least one of the following configurations: Narrowband Physical Random Access Channel (NPRACH) configuration or transmission rules, Random Access Response (RAR) window configuration or enabling rules, or Contention Resolution Window configuration or enabling rules.

4. The method according to claim 1, wherein, The satellite communication method also includes: Send a third message, wherein the third message includes a preamble; Based on the available downlink resource location information in the first TDD frame structure, monitoring of the RAR is started. The available downlink resource location information includes at least one of the following: TDD frame structure pattern information, the length of the RAR window, or the offset value.

5. The method according to claim 1, wherein, The satellite communication method also includes: Send a fourth message, which is used to request connection establishment; Based on the available downlink resource location information in the first TDD frame structure, monitoring for contention resolution is enabled. The available downlink resource location information includes at least one of the following: TDD frame structure pattern information, the length of the contention resolution window, or an offset value.

6. The method according to claim 1, wherein, The original NSSS sequence in the NSSS frame structure pattern information is repeatedly transmitted between subframes.

7. The method of claim 6, wherein a period of the first TDD frame structure contains M or N radio frames, and a period of the first TDD frame structure contains only one radio frame for downlink transmission.

8. The method according to claim 1 or 6, wherein, The second period of the second TDD frame structure is the first value, and the second period is the time interval between the start subframes of two activated downlink transmissions. The activated downlink transmission includes N subframes, and the configuration methods for activating the downlink transmission include: Taking two consecutive radio frames in the preset first TDD frame structure as a reference, the subframe K position of the first radio frame in the two consecutive radio frames is taken as the starting subframe of the radio frame used for downlink transmission. The subframe L position of the second radio frame in two consecutive radio frames is used as the terminating subframe of the radio frame used for downlink transmission.

9. The method according to claim 7 or 8, wherein, The configuration methods for the NSSS frame structure pattern information include: Four different NSSS sequences are sequentially mapped between each radio frame used for downlink transmission or active downlink transmission, and an NSSS sequence is mapped at a preset subframe position in each radio frame used for downlink transmission or active downlink transmission.

10. The method according to claim 7 or 8, wherein, The configuration methods for the NSSS frame structure pattern information include: Two different NSSS sequences are mapped in each radio frame used for downlink transmission or in each active downlink transmission.

11. The method according to claim 7 or 8, wherein, The configuration methods for the NSSS frame structure pattern information include: Four different NSSS sequences are mapped in each radio frame used for downlink transmission or in active downlink transmission, and four different NSSS sequences are mapped at four preset subframe positions in each radio frame used for downlink transmission or in active downlink transmission.

12. The method of claim 6, wherein a period of the first TDD frame structure comprises M or N radio frames, and a period of the first TDD frame structure comprises only two radio frames for downlink transmission, the two radio frames for downlink transmission comprising a first radio frame for downlink transmission and a second radio frame for downlink transmission.

13. The method according to claim 12, wherein, The configuration methods for the NSSS frame structure pattern information include: Four different NSSS sequences are sequentially mapped during each first TDD cycle, and an NSSS sequence is mapped in a preset subframe position in the first or second radio frame used for downlink transmission, wherein the first TDD cycle is the first cycle of the first TDD frame structure.

14. The method according to claim 12, wherein, The configuration methods for the NSSS frame structure pattern information include: Four different NSSS sequences are cyclically mapped between each radio frame used for downlink transmission.

15. The method according to claim 12, wherein, The configuration methods for the NSSS frame structure pattern information include: Two different NSSS sequences are mapped in each radio frame used for downlink transmission, with different NSSS sequences mapped at two preset subframe positions in the first radio frame and different NSSS sequences mapped at two preset subframe positions in the second radio frame.

16. The method according to claim 12, wherein, The configuration methods for the NSSS frame structure pattern information include: Two different NSSS sequences are mapped in each first TDD cycle, and different NSSS sequences are mapped in two preset subframe positions of the first or second radio frame used for downlink transmission.

17. The method according to claim 12, wherein, The configuration methods for the NSSS frame structure pattern information include: Four different NSSS sequences are mapped in each first TDD cycle; Different NSSS sequences are mapped at four preset subframe positions in each of the first or second radio frames.

18. The method according to claim 6, wherein, The first period of the first TDD frame structure is a first value. One period of the first TDD frame structure contains M radio frames. One period of the first TDD frame structure contains only three radio frames used for downlink transmission.

19. The method according to claim 18, wherein, The configuration methods for the NSSS frame structure pattern information include: Four different NSSS sequences were mapped in the three first TDD cycles; Four different NSSS sequences are sequentially mapped between each even-numbered radio frame. The even-numbered radio frames are radio frames used for downlink transmission located at even positions in the first TDD frame structure. Only one subframe in each even-numbered radio frame is available to map the NSSS sequence.

20. The method according to claim 18, wherein, The configuration methods for the NSSS frame structure pattern information include: Four different NSSS sequences were mapped in the two first TDD cycles; Four different NSSS sequences are cyclically mapped between each radio frame used for downlink transmission, wherein only one subframe in each radio frame used for downlink transmission maps the NSSS sequence.

21. The method according to claim 1, wherein, The NPBCH carries the narrowband main information block MIB-NB, and the MIB-NB contains bit values ​​for indicating the number of high-order bits of frame information. The satellite communication method further includes: When the bit value is the first bit value, each NPBCH original sequence is transmitted repeatedly eight times; When the bit value is the second bit value, each NPBCH original sequence is transmitted four times repeatedly; When the bit value is the third bit value, each NPBCH original sequence is transmitted twice; When the bit value is the fourth bit value, each NPBCH original sequence is transmitted repeatedly once.

22. The method of claim 21, wherein one period of the first TDD frame structure contains only one, two, or three radio frames for downlink transmission.

23. The method according to claim 8 or 22, wherein, Each radio frame used for downlink transmission or activating downlink transmission includes one, two, or four preset subframes for transmitting NPBCH sequences, wherein the bit value is the first bit value, and the configuration method of the NPBCH frame structure pattern information includes: Sixty-four different NPBCH sequences are sequentially and cyclically mapped between preset subframe positions used for transmitting NPBCH sequences.

24. The method according to claim 8 or 22, wherein, Each radio frame used for downlink transmission or activating downlink transmission includes one, two, or four preset subframes for transmitting NPBCH sequences, wherein the bit value is the second bit value, and the configuration method of the NPBCH frame structure pattern information includes: 32 different NPBCH sequences are sequentially and cyclically mapped between preset subframe positions used for transmitting NPBCH sequences.

25. The method according to claim 8 or 22, wherein, Each radio frame used for downlink transmission or activating downlink transmission includes one, two, or four preset subframes for transmitting NPBCH sequences, wherein the bit value is the third bit value, and the configuration method of the NPBCH frame structure pattern information includes: Sixteen different NPBCH sequences are sequentially mapped cyclically between preset subframe positions used for transmitting NPBCH sequences.

26. The method according to claim 8 or 22, wherein, Each radio frame used for downlink transmission or activating downlink transmission includes one, two, or four preset subframes for transmitting NPBCH sequences, wherein the bit value is the fourth bit value, and the configuration method of the NPBCH frame structure pattern information includes: Eight different NPBCH sequences are sequentially and cyclically mapped between each preset subframe position used for transmitting NPBCH sequences.

27. The method according to claim 2, wherein, The satellite communication method also includes: The update frame structure is determined based on at least one of the system message, RRC, MAC CE, and / or DCI.

28. The method according to claim 27, wherein, The configuration method of the update frame structure includes at least one of the following: The number of radio frames is configured in at least one of the system messages, RRC, MAC CE and / or DCI, and the number of radio frames corresponds to a fixed frame pattern; The number of radio frames is configured in at least one of the system messages, RRC, MAC CE and / or DCI, and there is a mapping relationship between the number of radio frames and the frame pattern; A predefined number of wireless frames is configured with an index in at least one of the system messages, RRC, MAC CE, and / or DCI, wherein the index is used to indicate the frame pattern; or, Configure at least one of the following parameters in at least one of the system messages, RRC, MAC CE and / or DCI: number of radio frames, number of downlink transmission frames or subframes, number of guard interval frames or subframes, and number of uplink transmission frames or subframes.

29. The method according to claim 2, wherein, The configuration method for activating the uplink and downlink frame structure includes at least one of the following: Configure and activate downlink start position information, downlink duration, protection interval duration, and uplink duration; Configure and activate downlink start position information and protection interval start position information. And the duration of the protection interval and the duration of the uplink; Configure the activation start position information for downlink, the activation end position information for uplink, the duration of downlink, and the duration of the protection interval; Configure the activation of uplink start position information, activation of downlink start position information, uplink duration, downlink duration, and protection interval duration; Configure the activation of downlink start position information, downlink duration, and protection interval duration; or, Configure the start position of the activation cycle, as well as the activation uplink start position information, the uplink duration, and the downlink duration.

30. The method according to claim 2, wherein, The configuration methods for the RAR window include: Based on the first TDD frame structure, an offset value based on a first reference time point is configured, wherein the first reference time point is the time point when the RAR window opens or the time point when the RAR window closes. or, In TDD mode, the RAR window starts at the subframe where the last NRPACH repetition occurs, and the length of the RAR window is X subframes plus the round-trip communication delay between the two nodes, where X is associated with the structure of the first TDD frame.

31. The method according to claim 2, wherein, The configuration methods for the contention resolution window include: Based on the first TDD frame structure, an offset value based on a second reference time point is configured, wherein the second reference time point is the time point when the contention resolution window opens or the time point when the contention resolution window closes; or, In TDD mode, the start time of the contention resolution timer is delayed until the next available downlink frame.

32. The method according to claim 3, wherein, The NPRACH configuration or transmission rules include: Configure the NPRACH period in the system information, and the period is associated with the period parameter of the radio frame; or, The NPRACH transmission timing is located within the guard interval or downlink frame, and the NPRACH is transmitted starting from the first subframe of the uplink resource closest to the random access channel timing RO; or, NPRACH is sent only when the RO is in an available uplink resource.

33. A satellite communication method in Time Division Duplex (TDD) mode, executed at a base station, the satellite communication method comprising: The first information is determined; wherein the first information includes at least one of the following: narrowband secondary synchronization signal (NSSS) frame structure pattern information and narrowband physical broadcast channel (NPBCH) frame structure pattern information; wherein the NSSS frame structure pattern information is the pattern information of NSSS in time division duplex (TDD) mode, the NPBCH frame structure pattern information is the pattern information of NPBCH in TDD mode, the first period of the first TDD frame structure in TDD mode is a first value or a second value, and the configuration method of the NPBCH frame structure pattern information includes at least one of the following: the original NPBCH sequence is repeatedly transmitted between subframes and / or between radio frames, or the number of repetitions of the original NPBCH sequence is reduced based on the bit value of the most significant bit (MSB) in the narrowband main information block (MIB-NB); Based on the first information, a first signal is sent, wherein the first signal is a downlink synchronization signal, and the first signal includes at least one of the following: the NSSS, the NPBCH, or the narrowband primary synchronization signal NPSS.

34. The method according to claim 33, wherein, The satellite communication method also includes: Send a second message, which includes at least one of the following: system message or frame configuration information, wherein the frame configuration information includes at least one of the following: wireless frame number and frame pattern corresponding to different frame numbers, activated uplink / downlink frame structure, activated reference point information, protection interval for downlink to uplink handover, duration of activated uplink / downlink, random access response (RAR) window and contention resolution window.

35. The method according to claim 33, wherein, The satellite communication method also includes: Determine at least one of the following configurations: Narrowband Physical Random Access Channel (NPRACH) configuration or transmission rules, Random Access Response (RAR) window configuration or enabling rules, or Contention Resolution Window configuration or enabling rules.

36. The method according to claim 33, wherein, The satellite communication method also includes: Receive third information, wherein the third information includes a preamble; Based on the available downlink resource location information in the first TDD frame structure, monitoring of the RAR is started. The available downlink resource location information includes at least one of the following: TDD frame structure pattern information, the length of the RAR window, or the offset value.

37. The method according to claim 33, wherein, The satellite communication method also includes: Receive fourth information, which is used to request connection establishment; Based on the available downlink resource location information in the first TDD frame structure, monitoring for contention resolution is enabled. The available downlink resource location information includes at least one of the following: TDD frame structure pattern information, the length of the contention resolution window, or an offset value.

38. The method according to claim 33, wherein, The original NSSS sequence in the NSSS frame structure pattern information is repeatedly transmitted between subframes.

39. The method of claim 38, wherein a period of the first TDD frame structure comprises M or N radio frames, and a period of the first TDD frame structure comprises only one radio frame for downlink transmission.

40. The method according to claim 33 or 38, wherein, The second period of the second TDD frame structure is the first value, and the second period is the time interval between the start subframes of two activated downlink transmissions. The activated downlink transmission includes N subframes, and the configuration methods for activating the downlink transmission include: Taking two consecutive radio frames in the preset first TDD frame structure as a reference, the subframe K position of the first radio frame in the two consecutive radio frames is taken as the starting subframe of the radio frame used for downlink transmission. The subframe L position of the second radio frame in two consecutive radio frames is used as the terminating subframe of the radio frame used for downlink transmission.

41. The method according to claim 39 or 40, wherein, The configuration methods for the NSSS frame structure pattern information include: Four different NSSS sequences are sequentially mapped between each radio frame used for downlink transmission or active downlink transmission, and an NSSS sequence is mapped at a preset subframe position in each radio frame used for downlink transmission or active downlink transmission.

42. The method according to claim 39 or 40, wherein, The configuration methods for the NSSS frame structure pattern information include: Two different NSSS sequences are mapped in each radio frame used for downlink transmission or in each active downlink transmission.

43. The method according to claim 39 or 40, wherein, The configuration methods for the NSSS frame structure pattern information include: Four different NSSS sequences are mapped in each radio frame used for downlink transmission or in active downlink transmission, and four different NSSS sequences are mapped at four preset subframe positions in each radio frame used for downlink transmission or in active downlink transmission.

44. The method of claim 38, wherein a period of the first TDD frame structure comprises M or N radio frames, and a period of the first TDD frame structure comprises only two radio frames for downlink transmission, the two radio frames for downlink transmission comprising a first radio frame for downlink transmission and a second radio frame for downlink transmission.

45. The method according to claim 44, wherein, The configuration methods for the NSSS frame structure pattern information include: Four different NSSS sequences are sequentially mapped during each first TDD cycle, and an NSSS sequence is mapped in a preset subframe position in the first or second radio frame used for downlink transmission, wherein the first TDD cycle is the first cycle of the first TDD frame structure.

46. ​​The method of claim 44, wherein, The configuration methods for the NSSS frame structure pattern information include: Four different NSSS sequences are cyclically mapped between each radio frame used for downlink transmission.

47. The method of claim 44, wherein, The configuration methods for the NSSS frame structure pattern information include: Two different NSSS sequences are mapped in each radio frame used for downlink transmission, with different NSSS sequences mapped at two preset subframe positions in the first radio frame and different NSSS sequences mapped at two preset subframe positions in the second radio frame.

48. The method according to claim 44, wherein, The configuration methods for the NSSS frame structure pattern information include: Two different NSSS sequences are mapped in each first TDD cycle, and different NSSS sequences are mapped in two preset subframe positions of the first or second radio frame used for downlink transmission.

49. The method according to claim 44, wherein, The configuration methods for the NSSS frame structure pattern information include: Four different NSSS sequences are mapped in each first TDD cycle; Different NSSS sequences are mapped at four preset subframe positions in each of the first or second radio frames.

50. The method according to claim 38, wherein, The first period of the first TDD frame structure is a first value. One period of the first TDD frame structure contains M radio frames. One period of the first TDD frame structure contains only three radio frames used for downlink transmission.

51. The method according to claim 50, wherein, The configuration methods for the NSSS frame structure pattern information include: Four different NSSS sequences were mapped in the three first TDD cycles; Four different NSSS sequences are sequentially mapped between each even-numbered radio frame. The even-numbered radio frames are radio frames used for downlink transmission located at even positions in the first TDD frame structure. Only one subframe in each even-numbered radio frame is available to map the NSSS sequence.

52. The method according to claim 50, wherein, The configuration methods for the NSSS frame structure pattern information include: Four different NSSS sequences were mapped in the two first TDD cycles; Four different NSSS sequences are cyclically mapped between each radio frame used for downlink transmission, wherein only one subframe in each radio frame used for downlink transmission maps the NSSS sequence.

53. The method according to claim 33, wherein, The NPBCH carries the narrowband main information block MIB-NB, and the MIB-NB contains bit values ​​for indicating the number of high-order bits of frame information. The satellite communication method further includes: When the bit value is the first bit value, each NPBCH original sequence is transmitted repeatedly eight times; When the bit value is the second bit value, each NPBCH original sequence is transmitted four times repeatedly; When the bit value is the third bit value, each NPBCH original sequence is transmitted twice; When the bit value is the fourth bit value, each NPBCH original sequence is transmitted repeatedly once.

54. The method of claim 53, wherein one period of the first TDD frame structure contains only one, two, or three radio frames for downlink transmission.

55. The method according to claim 40 or 54, wherein, Each radio frame used for downlink transmission or activating downlink transmission includes one, two, or four preset subframes for transmitting NPBCH sequences, wherein the bit value is the first bit value, and the configuration method of the NPBCH frame structure pattern information includes: Sixty-four different NPBCH sequences are sequentially and cyclically mapped between preset subframe positions used for transmitting NPBCH sequences.

56. The method according to claim 40 or 54, wherein, Each radio frame used for downlink transmission or activating downlink transmission includes one, two, or four preset subframes for transmitting NPBCH sequences, wherein the bit value is the second bit value, and the configuration method of the NPBCH frame structure pattern information includes: 32 different NPBCH sequences are sequentially and cyclically mapped between preset subframe positions used for transmitting NPBCH sequences.

57. The method according to claim 40 or 54, wherein, Each radio frame used for downlink transmission or activating downlink transmission includes one, two, or four preset subframes for transmitting NPBCH sequences, wherein the bit value is the third bit value, and the configuration method of the NPBCH frame structure pattern information includes: Sixteen different NPBCH sequences are sequentially mapped cyclically between preset subframe positions used for transmitting NPBCH sequences.

58. The method according to claim 40 or 54, wherein, Each radio frame used for downlink transmission or activating downlink transmission includes one, two, or four preset subframes for transmitting NPBCH sequences, wherein the bit value is the fourth bit value, and the configuration method of the NPBCH frame structure pattern information includes: Eight different NPBCH sequences are sequentially and cyclically mapped between each preset subframe position used for transmitting NPBCH sequences.

59. The method according to claim 34, wherein, The satellite communication method also includes: The update frame structure is determined based on at least one of the system message, RRC, MAC CE, and / or DCI.

60. The method according to claim 59, wherein, The configuration method of the update frame structure includes at least one of the following: The number of radio frames is configured in at least one of the system messages, RRC, MAC CE and / or DCI, and the number of radio frames corresponds to a fixed frame pattern; The number of radio frames is configured in at least one of the system messages, RRC, MAC CE and / or DCI, and there is a mapping relationship between the number of radio frames and the frame pattern; A predefined number of wireless frames is configured with an index in at least one of the system messages, RRC, MAC CE, and / or DCI, wherein the index is used to indicate the frame pattern; or, Configure at least one of the following parameters in at least one of the system messages, RRC, MAC CE and / or DCI: number of radio frames, number of downlink transmission frames or subframes, number of guard interval frames or subframes, and number of uplink transmission frames or subframes.

61. The method according to claim 34, wherein, The configuration method for activating the uplink and downlink frame structure includes at least one of the following: Configure and activate downlink start position information, downlink duration, protection interval duration, and uplink duration; Configure and activate downlink start position information and protection interval start position information. And the duration of the protection interval and the duration of the uplink; Configure the activation start position information for downlink, the activation end position information for uplink, the duration of downlink, and the duration of the protection interval; Configure the activation of uplink start position information, activation of downlink start position information, uplink duration, downlink duration, and protection interval duration; Configure the activation of downlink start position information, downlink duration, and protection interval duration; or, Configure the start position of the activation cycle, as well as the activation uplink start position information, the uplink duration, and the downlink duration.

62. The method according to claim 34, wherein, The configuration methods for the RAR window include: Based on the first TDD frame structure, an offset value based on a first reference time point is configured, wherein the first reference time point is the time point when the RAR window opens or the time point when the RAR window closes. or, In TDD mode, the RAR window starts at the subframe where the last NRPACH repetition occurs, and the length of the RAR window is X subframes plus the round-trip communication delay between the two nodes, where X is associated with the structure of the first TDD frame.

63. The method according to claim 34, wherein, The configuration methods for the contention resolution window include: Based on the first TDD frame structure, an offset value based on a second reference time point is configured, wherein the second reference time point is the time point when the contention resolution window opens or the time point when the contention resolution window closes; or, In TDD mode, the start time of the contention resolution timer is delayed until the next available downlink frame.

64. The method according to claim 35, wherein, The NPRACH configuration or transmission rules include: Configure the NPRACH period in the system information, and the period is associated with the period parameter of the radio frame; or, The NPRACH transmission timing is located within the guard interval or downlink frame. The user equipment starts transmitting NPRACH in the first subframe of the uplink resource closest to the random access channel timing RO. or, The user equipment sends NPRACH only when the RO is in an available uplink resource.

65. A wireless communication device, wherein, The satellite communication device in Time Division Duplex (TDD) mode includes a processor and a memory, the memory being used to store computer programs, and the processor being used to call and run the computer programs stored in the memory to execute the satellite communication method as described in any one of claims 1 to 64.

66. A readable storage medium for storing a computer program that is invoked and executed by a processor to perform the method as described in any one of 1-64.

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