A method for processing low resource consumption satellite-to-ground frame disassembly and assembly on-board a forwarding satellite communication

Abstract

The present invention belongs to the field of satellite communication technology, and relates to a method for processing and forwarding satellite communication satellite-to-ground frame disassembly and assembly with low resource consumption, including: (1) when the ground terminal on the sending side splits the link layer frame, the link layer frame is split according to the physical channel burst length, frame type, priority and allocated time slot resources, and the link layer frame header is added and filled in the burst in sequence; (2) the satellite identifies the frame type in the link layer frame header, reassembles the control frame, and forwards the service frame; (3) the receiving side terminal reassembles the received link layer frame according to the splitting identifier, source address and priority. The present invention splits the link layer frame to adapt to the physical layer burst length, effectively reduces the burst idle space, and significantly improves the link transmission efficiency; at the same time, the service frame adopts an end-to-end processing mode, which is split and reassembled by the ground without the participation of the satellite, which can greatly reduce the complexity of on-board processing and is suitable for on-board processing of satellite communication systems.

Description

Technical Field

[0001] The invention relates to a link layer frame disassembly technology in the field of satellite communication technology, and is particularly suitable for an on-board processing and forwarding satellite communication system. Background Art

[0002] Deframing technology is an indispensable work of the link layer of the satellite communication system, especially for continuous long frame services, which need to be reframed and transmitted according to the frame structure that conforms to the link layer. At present, the current deframing scenario mostly occurs in satellite communication systems based on transparent transponders, and usually adopts a segmented end-to-end deframing method, that is, between two satellite communication earth stations that can be reached by one hop satellite. There are two common splitting and reassembling methods, one is to deframe at the network layer, and the other is to deframe at the physical layer. Network layer deframing is to organize link layer frames according to burst length at the network layer, which has the problem of low bandwidth utilization and inability to adapt to burst length changes caused by link changes; physical layer deframing is to split and reassemble link layer frames at the physical layer (modem), and the modulator splits the link layer frames and the demodulator reassembles the link layer frames. When used for on-board processing and forwarding systems, satellites need to reassemble all split link layer frames, which has the problem of complex on-board processing and high resource consumption. Summary of the invention

[0003] The technical problem to be solved by the present invention is to avoid the shortcomings of the above-mentioned background technology and provide a satellite-ground integrated link layer de-framing method. The present invention adopts an end-to-end de-framing method, and both de-framing and re-framing are performed at the ground terminal, the link layer is unpacked at the ground sending end, and the link layer is reassembled at the ground receiving end, and the air interface transmission is a complete link layer frame.

[0004] The technical solution adopted by the present invention is:

[0005] A method for processing low resource consumption satellite-to-ground frame disassembly and assembly on a forwarding satellite communication satellite comprises the following steps:

[0006] (1) The ground terminal on the sending side splits the link layer frame. When splitting, the number of bursts to be filled and the length of each burst are calculated according to the allocated time slot resources, and the link layer frame to be sent is filled into the burst. If the link layer frame length is greater than the remaining length of the burst during filling, the link layer frame is intercepted according to the remaining length of the burst, the split flag in the link layer frame header is modified, and the frame header of the link layer frame is copied to the front of the remaining link layer frames; wherein the link layer frame header contains the split flag, priority flag, source address, destination address and frame type information;

[0007] (2) The onboard demodulator receives the burst sent by the ground terminal, extracts the link layer frame from the burst, and sends it to the onboard switch. The onboard switch processes the frame according to the frame type in the link layer frame header. If it is a control frame, the onboard switch determines whether it needs to be reassembled according to the split flag in the link layer frame header. If it is a complete link layer frame, it is directly sent to the onboard network control for processing. If it is an incomplete link layer frame, the onboard switch reassembles it according to the source address, priority flag and split flag in the link layer frame header, and then sends it to the onboard network control for processing after reassembly. If it is a service frame, the onboard switch sends it to the corresponding onboard modulator according to the forwarding flag, and the onboard modulator forwards the link layer frame on the satellite downlink;

[0008] (3) The ground terminal on the receiving side receives the satellite downlink data, parses the link layer frame, and determines whether it is split according to the split flag in the link layer frame header. If it is a complete link layer frame, the link layer frame is directly processed. If it is an incomplete link layer frame, it is reassembled according to the source address, priority flag and split flag in the link layer frame header, and then the link layer frame is processed after reassembly.

[0009] Furthermore, in step (1), when filling the link layer frame into the burst, the high priority link layer frame is filled first.

[0010] Furthermore, in step (1), the link layer frame of the same priority level needs to be filled after the previous link layer frame is fully filled before the next link layer frame can be filled.

[0011] Furthermore, in step (1), the split identifier may identify the corresponding link layer frame as a complete frame, a first segment, a middle segment, and a tail.

[0012] Furthermore, in step (1), when the destination address of the link layer frame is a satellite, the frame type is defined as a control frame, and the control frame is defined as the highest priority and is filled first. At the same time, the control frames of authentication, entry and exit signaling, and resource application are less than a minimum burst length.

[0013] Furthermore, in step (2), the onboard switch reassembles the frame according to the source address, priority identifier and split identifier in the link layer frame header. The specific processing process is as follows:

[0014] The onboard switch performs classification processing according to the split identifier. If the split identifier is the first segment, a local cache is requested according to the source address and priority identifier in the frame header. If it is the middle segment or the tail end, the link layer frame's payload is stored in the requested local cache in order according to the source address and priority identifier in the frame header. After receiving the tail end, the link layer frame is read from the cache for reassembly processing and the requested cache is released.

[0015] Furthermore, in step (3), after receiving the link layer frame, the receiving ground terminal first parses the destination address in the link layer frame header, and discards it if the destination address is not that of the terminal.

[0016] Furthermore, in step (3), the reassembly is performed according to the source address, priority flag and split flag in the link layer frame header. The specific processing process is as follows:

[0017] Classification processing is performed according to the split identifier. If the split identifier is the first segment, local cache is applied for according to the source address and priority identifier in the frame header. If it is the middle segment or the tail end, the payload of the link layer frame is stored in the applied local cache in order according to the source address and priority identifier in the frame header. At the same time, after receiving the tail end, the link layer frame is read from the cache for reassembly processing, and the applied cache is released.

[0018] Furthermore, it is characterized in that when the ground terminal receives the link layer frame splitting mark as the first segment, it first searches whether the local cache has been applied for according to the source address and priority in the frame header. If the local cache has been applied for, the applied cache is released and the cache application is made again.

[0019] Compared with the background technology, the present invention has the following advantages:

[0020] 1) The present invention performs both the splitting and reassembly of link layer frames at the ground terminal, and does not require satellite-borne equipment to perform special processing on the link layer frames, so the satellite processing complexity is low;

[0021] 2) When splitting link layer frames, the present invention supports high-priority link layer frames interrupting the transmission of low-priority link layer frames, and supports priority-based integrated service transmission;

[0022] 3) The present invention can fill the next link layer frame when the remaining burst length is greater than the link layer frame header, and the transmission efficiency is high;

[0023] 4) The present invention performs the splitting and reassembly of link layer frames at the link layer, the inter-layer interface is clear, the link layer and the physical layer are complete link layer frames, and the air interface transmission data are complete link layer frames;

[0024] 5) The present invention has the advantages of clear inter-layer interface and support for priority-based integrated service transmission. When used in an on-board processing and forwarding system, it has the advantage of simple on-board processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the satellite-ground integrated link layer de-framing method of the present invention.

[0026] Figure 2 This is a schematic diagram of the link layer frame header of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0028] like Figure 1 As shown, ground terminal 1 is a sending side ground terminal, ground terminal 2 is a receiving side ground terminal, and the onboard processing load includes a satellite demodulator, a satellite switch, a satellite modulator and a satellite network control.

[0029] A method for processing low resource consumption satellite-to-ground frame disassembly and assembly on a forwarding satellite communication satellite, the specific steps comprising:

[0030] (1) The ground terminal splits the link layer frame: The ground terminal on the sending side splits the link layer frame. When splitting, it calculates the number of bursts to be filled and the length of each burst based on the allocated time slot resources, and fills the link layer frame to be sent into the burst. If the link layer frame length is greater than the remaining length of the burst during filling, the link layer frame is intercepted according to the remaining length of the burst, the split flag in the link layer frame header is modified, and the frame header of the link layer frame is copied to the front of the remaining link layer frames to ensure that the burst is filled with complete link layer frames.

[0031] like Figure 2 As shown, the link layer frame header includes a split flag, a priority flag, a source address, a destination address and frame type information; wherein the split flag can identify the corresponding link layer frame as a complete frame, a first segment, a middle segment and a tail end.

[0032] Furthermore, when burst filling of link layer frames is performed, high priority link layer frames are filled first, and link layer frames of the same priority can only be filled in the next link layer frame after the previous link layer frame is fully filled.

[0033] Furthermore, when the destination address of the link layer frame is satellite, the frame type is defined as a control frame. The control frame is defined as the highest priority and is filled first. At the same time, the frame length of the control frame is strictly controlled. Control frames such as authentication, entry and exit signaling, and resource application must be less than a minimum burst length and do not need to be split. The splitting method of variable-length control frames such as routing tables is the same as that of business frames.

[0034] (2) Satellite classification performs different frame disassembly and processing: The onboard demodulator receives the burst sent by the ground terminal, extracts the link layer frame from the burst, and sends it to the onboard switch. The onboard switch processes the frame according to the frame type in the link layer frame header. If it is a control frame, the onboard switch determines whether it needs to be reassembled based on the split flag in the link layer frame header. If it is a complete link layer frame, it is directly sent to the onboard network control for processing. If it is an incomplete link layer frame, the onboard switch reassembles it based on the source address, priority flag and split flag in the link layer frame header, and then sends it to the onboard network control for processing after reassembly. If it is a service frame, the onboard switch sends it to the corresponding onboard modulation based on the forwarding flag, and the onboard modulation forwards the link layer frame on the satellite downlink.

[0035] Among them, the reorganization is performed according to the source address, priority identifier and split identifier in the link layer frame header. The specific processing process is as follows:

[0036] Classification processing is performed according to the split identifier. If the split identifier is the first segment, local cache is applied for according to the source address and priority identifier in the frame header. If it is the middle segment or the tail end, the payload of the link layer frame is stored in the applied local cache in order according to the source address and priority identifier in the frame header. At the same time, after receiving the tail end, the link layer frame is read from the cache for reassembly processing, and the applied cache is released.

[0037] (3) The ground terminal reassembles the link layer data: When the ground terminal receives the satellite downlink data, it first parses the destination address in the link layer frame header. If the destination address is not that of the terminal, it is discarded. If the destination address is that of the terminal, it parses the link layer frame and determines whether the frame is split according to the split flag in the link layer frame header. If it is a complete link layer frame, it directly processes the link layer frame. If it is an incomplete link layer frame, it reassembles the frame according to the source address, priority flag and split flag in the link layer frame header. After reassembly, it processes the link layer frame.

[0038] Among them, the reorganization is performed according to the source address, priority identifier and split identifier in the link layer frame header. The specific processing process is as follows:

[0039] Classification processing is performed according to the split identifier. If the split identifier is the first segment, local cache is applied for according to the source address and priority identifier in the frame header. If it is the middle segment or the tail end, the payload of the link layer frame is stored in the applied local cache in order according to the source address and priority identifier in the frame header. At the same time, after receiving the tail end, the link layer frame is read from the cache for reassembly processing, and the applied cache is released.

[0040] Furthermore, when the ground terminal receives the link layer frame splitting mark as the first segment, it first searches whether the local cache has been applied for based on the source address and priority in the frame header. If the local cache has been applied for, the applied cache is released and the cache is applied for again to prevent cache leakage due to the loss of the tail end of the previous split link layer frame.

[0041] Finally, it should be noted that the above is only a preferred example of the present invention. Although the present invention has been described in detail with reference to the above embodiments, it is still possible for those skilled in the art to modify the technical solutions of the aforementioned embodiments or to make equivalent substitutions for other parts of the technical features. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for processing low resource consumption satellite-to-ground frame disassembly and assembly on a satellite for forwarding satellite communication, characterized in that: The following steps are involved: (1) The ground terminal on the sending side splits the link layer frame. When splitting, the number of bursts to be filled and the length of each burst are calculated according to the allocated time slot resources, and the link layer frame to be sent is filled into the burst. If the link layer frame length is greater than the remaining length of the burst during filling, the link layer frame is intercepted according to the remaining length of the burst, the split flag in the link layer frame header is modified, and the frame header of the link layer frame is copied to the front of the remaining link layer frames; wherein the link layer frame header contains the split flag, priority flag, source address, destination address and frame type information; (2) The onboard demodulator receives the burst sent by the ground terminal, extracts the link layer frame from the burst, and sends it to the onboard switch. The onboard switch processes the frame according to the frame type in the link layer frame header. If it is a control frame, the onboard switch determines whether it needs to be reassembled according to the split flag in the link layer frame header. If it is a complete link layer frame, it is directly sent to the onboard network control for processing. If it is an incomplete link layer frame, the onboard switch reassembles it according to the source address, priority flag and split flag in the link layer frame header, and then sends it to the onboard network control for processing after reassembly. If it is a service frame, the onboard switch sends it to the corresponding onboard modulator according to the forwarding flag, and the onboard modulator forwards the link layer frame on the satellite downlink; (3) The ground terminal on the receiving side receives the satellite downlink data, parses the link layer frame, and determines whether it is split according to the split flag in the link layer frame header. If it is a complete link layer frame, the link layer frame is directly processed. If it is an incomplete link layer frame, it is reassembled according to the source address, priority flag and split flag in the link layer frame header, and then the link layer frame is processed after reassembly.

2. A method for processing and forwarding satellite communication on-board low resource consumption satellite-to-ground frame disassembly and assembly according to claim 1, characterized in that: In step (1), when filling the link layer frame to the burst, the high priority link layer frame is filled first.

3. The method for processing and forwarding satellite communication on-board low resource consumption satellite-to-ground frame disassembly and assembly according to claim 1, characterized in that: In step (1), the link layer frame of the same priority level must be filled after the previous link layer frame is fully filled before the next link layer frame can be filled.

4. The method for processing and forwarding satellite communication on-board low resource consumption satellite-to-ground frame disassembly and assembly according to claim 1, characterized in that: In step (1), the split identifier can identify the corresponding link layer frame as a complete frame, a first segment, a middle segment and a tail end.

5. The method for processing and forwarding satellite communication on-board low resource consumption satellite-to-ground frame disassembly and assembly according to claim 1, characterized in that: In step (1), when the destination address of the link layer frame is a satellite, the frame type is defined as a control frame, and the control frame is defined as the highest priority and is filled first. At the same time, the control frames of authentication, entry and exit signaling, and resource application are less than a minimum burst length.

6. A method for processing and forwarding satellite communication on-board low resource consumption satellite-to-ground frame disassembly and assembly according to claim 4, characterized in that: In step (2), the onboard switch reassembles the frames according to the source address, priority identifier and split identifier in the link layer frame header. The specific processing process is as follows: The onboard switch performs classification processing according to the split identifier. If the split identifier is the first segment, a local cache is requested according to the source address and priority identifier in the frame header. If it is the middle segment or the tail end, the link layer frame's payload is stored in the requested local cache in order according to the source address and priority identifier in the frame header. After receiving the tail end, the link layer frame is read from the cache for reassembly processing and the requested cache is released.

7. A method for processing and forwarding satellite communication on-board low resource consumption satellite-to-ground frame disassembly and assembly according to claim 1, characterized in that: In step (3), after receiving the link layer frame, the receiving ground terminal first parses the destination address in the link layer frame header. If the destination address is not that of the terminal, it is discarded.

8. The method for processing and forwarding satellite communication on-board low resource consumption satellite-to-ground frame disassembly and assembly according to claim 4, characterized in that: In step (3), the reassembly is performed according to the source address, priority flag and split flag in the link layer frame header. The specific processing process is as follows: Classification processing is performed according to the split identifier. If the split identifier is the first segment, local cache is applied for according to the source address and priority identifier in the frame header. If it is the middle segment or the tail end, the payload of the link layer frame is stored in the applied local cache in order according to the source address and priority identifier in the frame header. At the same time, after receiving the tail end, the link layer frame is read from the cache for reassembly processing, and the applied cache is released.

9. A method for processing and forwarding satellite communication on-board low resource consumption satellite-to-ground frame disassembly and assembly according to claim 8, characterized in that: When the ground terminal receives the link layer frame splitting mark as the first segment, it first searches whether the local cache has been applied for based on the source address and priority in the frame header. If the local cache has been applied for, the applied cache will be released and the cache will be applied for again.

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