A backward-compatible time slot for a maritime all-digital broadband communication system and its compatibility method

Abstract

The present invention provides a time slot of a backward - compatible all - digital broadband communication system for the sea and its compatibility method. The time slot of the present invention includes a ramp - up time, a synchronization time, a link ID time, a valid data time, a ramp - down time, and a protection time; wherein: the time - slot structure composed of the ramp - up time, the synchronization time, the link ID time, the valid data time, the ramp - down time, and the protection time is adaptively adjusted according to the equipment and rate transmission requirements of the communication node. The compatibility method of the present invention includes: when the communication node is an AIS device, setting K = 1 and S = 1, and adjusting it to the AIS time - slot structure; when the communication node is a VDES device, setting K = 1 and S = 1, and adjusting it to the ASM time - slot structure; when the communication node is a VDES device, setting K = 1, S = 2 or S = 4 or S = 8, and adjusting it to the terrestrial VDE time - slot structure; The present invention can adaptively adjust the time - slot structure according to the communication rate, greatly improving the number of nodes and the communication rate of the marine communication network. At the same time, it is compatible with the second - generation AIS and the third - generation VDES communication networks, solving the problem of backward compatibility in marine communication.

Description

Technical Field

[0001] The present invention relates to the field of maritime communication technologies, and more particularly, to a time slot of a backward-compatible all-digital broadband maritime communication system and a compatibility method therefor. Background Art

[0002] Maritime communication systems have gone through the first-generation analog voice communication, the second-generation Automatic Identification System (AIS for short), and the third-generation VHF Data Exchange System (VDES for short), and are currently evolving towards the fourth-generation all-digital broadband communication system. The third-generation VDES, while fully compatible with AIS, added ASM and VDE channels, effectively improving the rate of maritime communication and realizing the expansion of maritime communication services.

[0003] However, compared with terrestrial mobile communication, the rate of maritime communication is still low. The communication rate of AIS is only 9.6 kbps, the communication rate of ASM is 19.2 kbps, and the communication rate of VDE reaches 307.2 kbps. Compared with the communication rate of terrestrial mobile communication, which can reach several Mbps, the gap is large, and it still cannot meet the transmission of high-speed data. At the same time, in recent years, the number of maritime vessels has been increasing, and the number of offshore engineering equipment such as offshore operation platforms and aquaculture platforms has also been increasing rapidly, with a continuous growth trend, which has also led to a rapid increase in the number of nodes in the maritime communication network. Summary of the Invention

[0004] In view of the above-mentioned technical problems, a time slot of a backward-compatible all-digital broadband maritime communication system and a compatibility method therefor are provided. The present invention can adaptively adjust the time slot structure according to the communication object and rate transmission requirements, greatly improving the number of nodes and communication rate of the maritime communication network, and being compatible with the second-generation AIS and third-generation VDES communication networks, thus solving the backward compatibility problem of maritime communication.

[0005] The technical means adopted by the present invention are as follows:

[0006] A time slot of a backward-compatible all-digital broadband maritime communication system includes: a ramp-up time, a synchronization time, a link ID time, a valid data time, a ramp-down time, and a protection time; wherein:

[0007] The time slot structure composed of the ramp-up time, the synchronization time, the link ID time, the valid data time, the ramp-down time, and the protection time is adaptively adjusted according to the equipment and rate transmission requirements of the communication node.

[0008] Further, in the all-digital broadband maritime communication system:

[0009] The number of time slots per unit time of the maritime all-digital broadband communication system is N digital , and the number of time slots per unit time of the AIS system is N AIS . For the VDES system, the number of time slots per unit time of the ASM channel and the VDE channel are N ASM and N VDE respectively. Then, according to the standard, N AIS = N ASM = N VDE = 2250 slot / min;

[0010] Design N digital to be K times of N AIS and N VDES , and K ≥ 1, that is, N digital = N AIS × K = N VDES × K = 2250 × K slot / min;

[0011] The time of one time slot of the maritime all-digital broadband communication system is t digital , the time of one time slot of the AIS system is t AIS , and the time of one time slot of the ASM channel and the VDE channel of the VDES system are t ASM and t VDE respectively. According to the standard, Then

[0012] The symbol rate of the maritime all-digital broadband communication system is R digital , the symbol rate of the AIS system is R AIS , the symbol rate of ASM in the VDES system is R ASM , and the symbol rate of VDE is R VDE ; then according to the standard, R AIS = R ASM = 9600 symbol / s. Design R digital to be S times of R AIS , that is, R digital = R AIS × S = R ASM × S.

[0013] Furthermore, the VDE has three symbol rates, which are R VDE = R ASM × 2 = 19200 symbol / s, R VDE = R ASM × 4 = 38400 symbol / s, R VDE = R ASM × 8 = 76800 symbol / s.

[0014] Furthermore, in the time slot structure:

[0015] The ramp-up time is set to t1 digital , where M1 is the number of ramp-up symbols;

[0016] The synchronization time is set to t2 digital , where M2 is the number of synchronization symbols;

[0017] The link ID time is set to t3 digital , where M3 is the number of link ID symbols;

[0018] The valid data time is set to t4 digital , where M4 is the number of valid data symbols;

[0019] The ramp-down time is set to t5 digital , where M5 is the number of ramp-down symbols;

[0020] The protection time is set to t6 digital , where M6 is the number of protection time symbols.

[0021] Furthermore, in the time slot structure:

[0022] If the communication networks are all nodes of the maritime all-digital broadband communication system, then the nodes of the maritime all-digital broadband communication system all take the same K value and S value. At the same time, the maritime all-digital broadband communication system can work in a single time slot or in multiple time slots spliced together;

[0023] When multiple time slots are spliced, let the splicing number be n digital , then in the time slot structure, except for the valid data time, other times remain unchanged, and the valid data time is set as follows:

[0024]

[0025] Furthermore, in the valid data time, the modulation methods that the valid data can adopt include but are not limited to BPSK, QPSK, π / 4QPSK, 8PSK, 16QAM, 64QAM, 256QAM.

[0026] Furthermore, the time slot structure is adaptively adjusted to the AIS time slot structure, the ASM time slot structure, and the terrestrial VDE time slot structure according to the equipment and rate transmission requirements of the communication nodes.

[0027] The present invention also provides a compatibility method for time slots of the above-mentioned backward-compatible all-digital broadband communication system at sea, including: when the communication node is an AIS device, set K = 1 and S = 1, and the time slot structure of the all-digital broadband communication system at sea is adjusted to the AIS time slot structure. In the AIS time slot structure:

[0028] Ramp-up time: When M1 = 8, t1 AIS = 0.833 ms;

[0029] Synchronization time: When M2 = 24, t2 AIS = 2.500 ms;

[0030] Link ID time becomes start time: When M3 = 8, t3 AIS = 0.833 ms;

[0031] Valid data time: When M4 = 184, t4 AIS = 19.168 ms;

[0032] Ramp-down time: When M5 = 8, t5 AIS = 0.833 ms;

[0033] Guard time: When M6 = 24, t6 AIS = 2.500 ms;

[0034] The AIS time slot structure is a standard AIS single time slot structure, and the single time slot structure can be combined into a multi-time slot structure according to the standard specification.

[0035] Furthermore, when the communication node is a VDES device, set K = 1 and S = 1, and the time slot structure of the all-digital broadband communication system at sea is adjusted to the ASM time slot structure. In the ASM time slot structure:

[0036] Ramp-up time: When M1 = 4, t1 ASM = 0.417 ms;

[0037] Synchronization time: When M2 = 27, t2 ASM = 2.812 ms;

[0038] Link ID time: When M3 = 16, t3 ASM = 1.667 ms;

[0039] Valid data time: When M4 = 197, t4 ASM = 20.521 ms;

[0040] Descending time: When M5 = 4, t5 ASM = 0.417 ms;

[0041] Protection time: When M6 = 8, t6 ASM = 0.833 ms;

[0042] The ASM time slot structure is a standard ASM single time slot structure, and the single time slot structure can be combined into a multi - time slot structure according to the standard specification.

[0043] Furthermore, when the communication node is a VDES device, let K = 1, S = 2 or S = 4 or S = 8, the time slot structure of the maritime all - digital broadband communication system is adjusted to the ground VDE time slot structure, in the ground VDE time slot structure:

[0044] Rise - time: When M1 = 8 or M1 = 16 or M1 = 32, corresponding to R VDE = 19200, R VDE = 38400, R VDE = 76800, then the rise - time is t1 VDE = 0.417 ms;

[0045] Synchronization time: When M2 = 27, corresponding to R VDE = 19200, R VDE = 38400, R VDE = 76800, the synchronization times are t2 VDE = 1.406 ms, t2 VDE = 0.703 ms, t2 VDE = 0.351 ms;

[0046] Link ID time: When M3 = 16, corresponding to R VDE = 19200, R VDE = 38400, R VDE = 76800, the Link ID times respectively correspond to t3 VDE = 0.833 ms, t3 VDE = 0.417 ms, t3 VDE = 0.208 ms;

[0047] Valid data time: When M4 = 437 or M4 = 917 or M4 = 1877, the valid data times are t4 VDE = 22.761 ms, t4 VDE = 23.880 ms, t4 VDE = 24.441 ms;

[0048] Descending time: When M5 = 8 or M5 = 16 or M5 = 32, they respectively correspond to R VDE = 19200, R VDE = 38400, R VDE = 76800, then the ascending time is t5 ASM = 0.417 ms;

[0049] Protection time: When M6 = 16 or M6 = 32 or M6 = 64, t6 ASM = 0.833 ms:

[0050] The ground VDE time slot structure is a standard ground VDE single time slot structure, and the single time slot structure can be combined into a multi-time slot structure according to the standard specifications.

[0051] Compared with the prior art, the present invention has the following advantages:

[0052] 1. The time slot and its compatibility method of the backward compatible maritime all-digital broadband communication system provided by the present invention can adaptively adjust the time slot structure according to the communication rate, be backward compatible with the time slot structures of AIS, ASM, and VDE, and greatly increase the number of nodes and communication rate of the maritime communication network.

[0053] 2. The time slot and its compatibility method of the backward compatible maritime all-digital broadband communication system provided by the present invention can be compatible with the second-generation AIS and third-generation VDES communication networks, and solve the backward compatibility problem of maritime communication.

[0054] Based on the above reasons, the present invention can be widely promoted in the fields of maritime communication and the like. Brief Description of the Drawings

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0056] Figure 1 It is a schematic diagram of the number of time slots of the maritime all-digital broadband communication system of the present invention.

[0057] Figure 2 This is a schematic diagram of the single time slot structure of the all-digital broadband communication system for the present invention at sea.

[0058] Figure 3 This is a schematic diagram of the multi-time slot structure of the all-digital broadband communication system for the present invention at sea.

[0059] Figure 4 This is a schematic diagram of the AIS time slot structure with backward compatibility configuration for the present invention.

[0060] Figure 5 This is a schematic diagram of the ASM time slot structure with backward compatibility configuration for the present invention.

[0061] Figure 6 This is a schematic diagram of the VDE time slot structure with backward compatibility configuration for the present invention. Detailed implementation manners

[0062] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0063] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part rather than all of the embodiments of the present invention. The description of at least one exemplary embodiment below is actually only illustrative and in no way limits the present invention and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0064] It should be noted that the terms used here are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used here, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations.

[0065] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific values should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0066] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by orientation terms such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom", etc. are usually based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description. Without contrary description, these orientation terms do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus cannot be construed as limiting the protection scope of the present invention: the orientation terms "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0067] For the convenience of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above", etc. can be used here to describe the spatial positional relationships of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation described in the drawings for the device. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned as "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above..." can include both the orientations of "above..." and "below...". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations should be made for the spatial relative descriptions used here.

[0068] In addition, it should be noted that the use of words such as "first", "second", etc. to limit components is only for the convenience of differentiating the corresponding components. Without otherwise stating, the above words have no special meanings, and thus cannot be construed as limiting the protection scope of the present invention.

[0069] The present invention provides a time slot for a backward - compatible maritime all - digital broadband communication system, including: a ramp - up time, a synchronization time, a link ID time, a valid data time, a ramp - down time, and a protection time; wherein: the time - slot structure composed of the ramp - up time, the synchronization time, the link ID time, the valid data time, the ramp - down time, and the protection time is adaptively adjusted according to the device and rate transmission requirements of the communication node.

[0070] In specific implementation, as a preferred implementation manner of the present invention, as Figure 1 shown, in the maritime all - digital broadband communication system:

[0071] The number of time slots per unit time in the maritime all - digital broadband communication system is N digital , the number of time slots per unit time in the AIS system is N AIS , and the number of time slots per unit time in the ASM channel and the VDE channel of the VDES system are N ASM , N VDE respectively. Then, according to the standard, N AIS = N ASM = N VDE = 2250 slot / min;

[0072] Design N digital as K times of N AIS and N VDES , and K≥1, that is, N digital = N AIS ×K = N VDES ×K = 2250×K slot / min; in this embodiment, design N digital as K = 2 times of N AIS and N VDES , that is, N digital = N AIS ×K = N VDES ×K = 2250×K = 4500 slot / min.

[0073] The time of one time slot in the maritime all - digital broadband communication system is t digital , the time of one time slot in the AIS system is t AIS , and the time of one time slot in the ASM channel and the VDE channel of the VDES system are t ASM and t VDE respectively. According to the standard, Then In this embodiment,

[0074] The symbol rate of the maritime all - digital broadband communication system is R digital , the symbol rate of the AIS system is R AIS, the symbol rate of ASM in the VDES system is R ASM , the symbol rate of VDE is R VDE ; then according to the standard, R AIS = R ASM = 9600 symbol / s, and R digital is designed to be S times of R AIS , that is, R digital = R AIS × S = R ASM × S. In this embodiment, R digital is designed to be S = 32 times of R AIS , that is, R digital = R AIS × 32 = R ASM × 32 = 307.2 ksymbol / s. There are three symbol rates for VDE, which are R VDE = R ASM × 2 = 19200 symbol / s, R VDE = R ASM × 4 = 38400 symbol / s, R VDE = R ASM × 8 = 76800 symbol / s.

[0075] When specifically implemented, as a preferred implementation manner of the present invention, in the time slot structure:

[0076] The ramp-up time is set to t1 digital , where M1 is the number of ramp-up symbols, generally taking values of 4, 8, 16, 32, 64 or other values; in this embodiment, M1 takes the value of 64, then t1 digital = 0.208 ms;

[0077] The synchronization time is set to t2 digital , where M2 is the number of synchronization symbols, generally taking values of 24, 27, 54 or other values; in this embodiment, M2 takes the value of 54, then t2 digital = 0.176 ms;

[0078] The link ID time is set to t3 digital , where M3 is the number of link ID symbols, generally taking values of 8, 16, 32 or other values; in this embodiment, M3 takes the value of 32, then t3 digital = 0.104 ms;

[0079] The valid data time is set to t4 digital , Where M4 is the number of valid data symbols, and generally takes values of 184, 197, 3754 or other values; in this embodiment, M4 takes the value of 3754, then t4 digital = 12.220 ms;

[0080] The slow descent time is set to t5 digital , Where M5 is the number of slow descent symbols, and generally takes values of 4, 8, 16, 32, 64 or other values; in this embodiment, M5 takes the value of 64, then t5 digital = 0.208 ms;

[0081] The protection time is set to t6 digital , Where M6 is the number of protection time symbols, and generally takes values of 8, 16, 24, 32, 64, 128 or other values. In this embodiment, M6 takes the value of 128, then t6 digital = 0.417 ms.

[0082] In specific implementation, as a preferred implementation manner of the present invention, as Figure 3 shown, in the time slot structure: if the communication networks are all nodes of the maritime all-digital broadband communication system, then the nodes of the maritime all-digital broadband communication system all take the same K value and S value, and at the same time, the maritime all-digital broadband communication system can work in a single time slot or work after multi-time slot splicing;

[0083] When multi-time slot splicing is performed, let the splicing number be n digital , then in the time slot structure, except for the valid data time, other times remain unchanged, and the valid data time is set as follows:

[0084]

[0085] In this embodiment, let the splicing number be n digital = 2, then the valid data time is set as follows:

[0086]

[0087] In specific implementation, as a preferred implementation manner of the present invention, in the valid data time, the modulation methods that the valid data can adopt include but are not limited to BPSK, QPSK, π / 4QPSK, 8PSK, 16QAM, 64QAM, 256QAM. By adopting high-order modulation, the system communication rate will be greatly improved. In this embodiment, the valid data can adopt 16QAM or 64QAM. When 16QAM is adopted, the system communication rate will reach 1.2288 Mbps, and when 64QAM is adopted, the system communication rate will reach 1.8432 Mbps. Compared with the previous AIS system and VDES system, the communication rate has been greatly improved.

[0088] In specific implementation, as a preferred implementation manner of the present invention, the time slot structure is adaptively adjusted to an AIS time slot structure, an ASM time slot structure, and a terrestrial VDE time slot structure according to the device and rate transmission requirements of the communication node.

[0089] The present invention provides a compatibility method for the time slots of the above-mentioned backward-compatible all-digital broadband communication system at sea, including:

[0090] As Figure 4 shown, when the communication node is an AIS device, let K = 1 and S = 1, and the time slot structure of the all-digital broadband communication system at sea is adjusted to the AIS time slot structure. In the AIS time slot structure:

[0091] Ramp-up time: When M1 = 8, t1 AIS = 0.833 ms;

[0092] Synchronization time: When M2 = 24, t2 AIS = 2.500 ms;

[0093] Link ID time becomes start time: When M3 = 8, t3 AIS = 0.833 ms;

[0094] Valid data time: When M4 = 184, t4 AIS = 19.168 ms;

[0095] Ramp-down time: When M5 = 8, t5 AIS = 0.833 ms;

[0096] Guard time: When M6 = 24, t6 AIS = 2.500 ms;

[0097] The AIS time slot structure is a standard AIS single time slot structure, and the single time slot structure can be combined into a multi-time slot structure according to the standard specification.

[0098] As Figure 5 shown, when the communication node is a VDES device, let K = 1 and S = 1, and the time slot structure of the all-digital broadband communication system at sea is adjusted to the ASM time slot structure. In the ASM time slot structure:

[0099] Ramp-up time: When M1 = 4, t1 ASM = 0.417 ms;

[0100] Synchronization time: When M2 = 27, t2 ASM = 2.812 ms;

[0101] Link ID time: When M3 = 16, t3 ASM = 1.667 ms;

[0102] Valid data time: When M4 = 197, t4 ASM = 20.521 ms;

[0103] Descending time: When M5 = 4, t5 ASM = 0.417 ms;

[0104] Protection time: When M6 = 8, t6 ASM = 0.833 ms;

[0105] The ASM time slot structure is a standard ASM single time slot structure, and the single time slot structure can be combined into a multi - time slot structure according to the standard specification.

[0106] As Figure 6 shown, when the communication node is a VDES device, let K = 1, S = 2 or S = 4 or S = 8, the time slot structure of the maritime all - digital broadband communication system is adjusted to the ground VDE time slot structure. In the ground VDE time slot structure:

[0107] Ascending time: When M1 = 8 or M1 = 16 or M1 = 32, corresponding to R VDE = 19200, R VDE = 38400, R VDE = 76800, then the ascending time is t1 VDE = 0.417 ms;

[0108] Synchronization time: When M2 = 27, corresponding to R VDE = 19200, R VDE = 38400, R VDE = 76800, the synchronization times are t2 VDE = 1.406 ms, t2 VDE = 0.703 ms, t2 VDE = 0.351 ms;

[0109] Link ID time: When M3 = 16, corresponding to R VDE = 19200, RVDE = 38400, R VDE = 76800, and the link ID times correspond to t3 respectively VDE = 0.833 ms, t3 VDE = 0.417 ms, t3 VDE = 0.208 ms;

[0110] Valid data time: When M4 = 437 or M4 = 917 or M4 = 1877, the valid data times are t4 respectively VDE = 22.761 ms, t4 VDE = 23.880 ms, t4 VDE = 24.441 ms;

[0111] Descending time: When M5 = 8 or M5 = 16 or M5 = 32, they correspond to R respectively VDE = 19200, R VDE = 38400, R VDE = 76800, then the ascending time is t5 ASM = 0.417 ms;

[0112] Protection time: When M6 = 16 or M6 = 32 or M6 = 64, t6 ASM = 0.833 ms:

[0113] The ground VDE time slot structure is a standard ground VDE single time slot structure, and the single time slot structures can be combined into multi - time slot structures according to the standard specifications.

[0114] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A time slot of a backward - compatible maritime all - digital broadband communication system, characterized in that, Including: Ramp-up time, synchronization time, link ID time, valid data time, ramp-down time, and protection time; among which: The time slot structure composed of ramp-up time, synchronization time, link ID time, valid data time, ramp-down time, and protection time is adaptively adjusted according to the device and rate transmission requirements of the communication node. In the maritime all-digital broadband communication system: The number of time slots per unit time of the all-digital broadband communication system at sea is N digital , and the number of time slots per unit time of the AIS system is N AIS , and the number of time slots per unit time of the ASM channel and the VDE channel of the VDES system are N ASM and N VDE . Then, according to the standard, N AIS = N ASM = N VDE = 2250 slot / min; Design N digital For N AIS And N VDES Is K times that of N, and K ≥ 1, that is, N digital = N AIS × K = N VDES × K = 2250 × K slot / min; The time of one time slot in the maritime all-digital broadband communication system is t digital , and the time of one time slot in the AIS system is t AIS , and the times of one time slot in the ASM channel and the VDE channel of the VDES system are t ASM and t VDE , as can be seen from the standard, then The symbol rate of the all-digital broadband communication system at sea is R digital , the symbol rate of the AIS system is R AIS , the symbol rate of the ASM in the VDES system is R ASM , the symbol rate of the VDE is R VDE ; then according to the standard, R AIS = R ASM = 9600 symbol / s. Design R digital to be S times of R AIS , that is, R digital = R AIS × S = R ASM × S; In the time slot structure: The ramp-up time is set to t1 digital , where M1 is the number of ramp-up symbols; The synchronization time is set to t2 digital , where M2 is the number of synchronization symbols; The link ID time is set to t3 digital , where M3 is the number of link ID symbols; The valid data time is set to t4 digital , where M4 is the number of valid data symbols; The descent time is set to t5 digital , where M5 is the number of descent symbols; The protection time is set to t6 digital , where M6 is the number of protection time symbols; In the time slot structure: If the communication networks are all nodes of the maritime all-digital broadband communication system, then the nodes of the maritime all-digital broadband communication system all take the same K value and S value. At the same time, the maritime all-digital broadband communication system can work in a single time slot or after splicing multiple time slots. When performing multi-slot splicing, let the splicing number be n digital , then in the time slot structure, except for the valid data time, other times remain unchanged, and the valid data time is set as follows: The time slot structure is adaptively adjusted to the AIS time slot structure, ASM time slot structure, and terrestrial VDE time slot structure according to the device and rate transmission requirements of the communication node. When the communication node is an AIS device, let K = 1 and S = 1, and the time slot structure of the maritime all-digital broadband communication system is adjusted to the AIS time slot structure. In the AIS time slot structure: Rise time: When M1 = 8, t1 AIS = 0.833 ms; Synchronization time: When M2 = 24, t2 AIS = 2.500 ms; Link ID time becomes start time: When M3 = 8, t3 AIS = 0.833 ms; Valid data time: When M4 = 184, t4 AIS = 19.168 ms; Descent time: When M5 = 8, t5 AIS = 0.833 ms; Protection time: When M6 = 24, t6 AIS = 2.500 ms; The AIS time slot structure is a standard AIS single time slot structure, and the single time slot structure can be combined into a multi-time slot structure according to the standard specification. When the communication node is a VDES device, let K = 1 and S = 1, and the time slot structure of the maritime all-digital broadband communication system is adjusted to the ASM time slot structure. In the ASM time slot structure: Rise time: When M1 = 4, t1 ASM = 0.417 ms; Synchronization time: When M2 = 27, t2 ASM = 2.812 ms; Link ID Time: When M3 = 16, t3 ASM = 1.667 ms; Valid data time: When M4 = 197, t4 ASM = 20.521 ms; Descending time: When M5 = 4, t5 ASM = 0.417 ms; Protection time: When M6 = 8, t6 ASM = 0.833 ms; The ASM time slot structure is a standard ASM single time slot structure, and the single time slot structure can be combined into a multi-time slot structure according to the standard specification. When the communication node is a VDES device, let K = 1, S = 2 or S = 4 or S = 8, and the time slot structure of the maritime all-digital broadband communication system is adjusted to the terrestrial VDE time slot structure. In the terrestrial VDE time slot structure: Rise time: When M1 = 8 or M1 = 16 or M1 = 32, they respectively correspond to R VDE = 19200, R VDE = 38400, R VDE = 76800, then the rise time is t1 VDE = 0.417 ms; Synchronization time: When M2 = 27, corresponding to R VDE = 19200, R VDE = 38400, R VDE = 76800, and the synchronization times are t2 VDE = 1.406 ms, t2 VDE = 0.703 ms, t2 VDE = 0.351 ms; Link ID Time: When M3 = 16, corresponding to R VDE = 19200, R VDE = 38400, R VDE = 76800, and the link ID times respectively correspond to t3 VDE = 0.833 ms, t3 VDE = 0.417 ms, t3 VDE = 0.208 ms; Valid data time: When M4 = 437 or M4 = 917 or M4 = 1877, the valid data times are t4 VDE = 22.761 ms, t4 VDE = 23.880 ms, t4 VDE = 24.441 ms; Descending time: When M5 = 8 or M5 = 16 or M5 = 32, they respectively correspond to R VDE = 19200, R VDE = 38400, R VDE = 76800, then the ascending time is t5 ASM = 0.417ms; Protection time: When M6 = 16 or M6 = 32 or M6 = 64, t6 ASM = 0.833 ms: The terrestrial VDE time slot structure is a standard terrestrial VDE single time slot structure, and the single time slot structure can be combined into a multi-time slot structure according to the standard specification.

2. The time slot of the backward compatible all-digital broadband communication system at sea according to claim 1, wherein The VDE has three symbol rates, namely R VDE = R ASM × 2 = 19200 symbol / s, R VDE = R ASM × 4 = 38400 symbol / s, R VDE = R ASM × 8 = 76800 symbol / s.

3. The backward-compatible maritime all-digital broadband communication system time slot according to claim 1, characterized in that In the valid data time, the modulation methods that the valid data can adopt include but are not limited to BPSK, QPSK, π / 4QPSK, 8PSK, 16QAM, 64QAM, 256QAM.

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