CN-116471239-B - End-to-end transmission method, system, equipment and medium for long-delay high-error code communication environment

Abstract

An end-to-end transmission method, a system, equipment and a medium for a long-delay high-error code communication environment, wherein the method comprises the steps of firstly establishing connection between a source end and a destination end, sending a low-priority NIL packet to detect available resources of a network for quick start, disconnecting the connection and reestablishing the connection between the source end and the destination end when the start is successful, carrying out congestion window adjustment on congestion which occurs when the start is successful, disconnecting the connection and reestablishing the connection between the source end and the destination end when the adjustment is overtime, carrying out quick retransmission on lost packets, sending the lost packets again, carrying out quick recovery on the NIL packet, continuing to adjust a congestion window when the recovery is successful, disconnecting the connection and reestablishing the connection when the recovery is overtime; the invention improves the throughput of the network and shortens the end-to-end transmission time delay by quick start, congestion adjustment, quick retransmission and quick recovery.

Inventors

• ZHU YAN
• SHENG MIN
• XIE ZEHUI
• LI JIANDONG

Assignees

• 西安电子科技大学

Dates

Publication Date

20260512

Application Date

20230420

Claims (6)

1. 1. The end-to-end transmission method for the long-delay high-error code communication environment is characterized by comprising the following steps of: step 1, establishing connection between a source terminal and a destination terminal, and sending a low-priority NIL packet to detect available resources of a network, performing quick start, if the start is successful, executing step 2, if the start is overtime, disconnecting and reestablishing connection between the source terminal and the destination terminal, wherein the specific steps are as follows: Step 1.1, when a source end establishes connection by sending SYN packets, NIL packets are in a packet format regulated by a TCP protocol, an NIL flag bit is set by utilizing an undefined extension bit, NIL packets without data are sent, and the number of the sent NIL packets is see for oneself (1): (1) In the formula (1), num is the number of NIL packets, ssthresh is a slow start gate, and seg_size is the size of the NIL packets; Step 1.2, setting NIL packets to be low priority, analyzing after receiving the packets in the middle ground forwarding node and satellite node, checking whether NIL flag bit in the packets is 1, and discarding the NIL packets > NIL ACK packets > non-NIL packets when congestion occurs; Step 1.3, after the destination end receives the NIL packet, feeding back an NIL ACK packet to the source end, increasing a packet size in a congestion window every time the source end receives an NIL packet, increasing a packet before the third handshake connection is established, and after the connection is established and the packet is started to be sent, directly destroying the NIL packet by the source end, wherein the congestion window does not increase a packet size any more, and the starting is successful at the moment; step 1.4, after the source end sends connection establishment request information to the destination end, if the destination end does not feed back response information in time within a set time, the connection is disconnected and the connection between the source end and the destination end is reestablished; Step 2, when congestion occurs in the step 1, congestion window adjustment is carried out, if the adjustment is successful, the step 3 is executed, if the adjustment is overtime, the connection is disconnected, and the connection between the source end and the destination end is reestablished; step 3, when the lost packet appears in the step 1 and the step 2, the quick retransmission is carried out; and step 4, sending lost packets, quickly recovering the NIL packets, returning to the step 2 to continuously adjust the congestion window, and after the recovery is overtime, disconnecting and re-establishing the connection, wherein the specific steps are as follows: step 4.1, after receiving NIL grouping, a router of a satellite node in the satellite network increases a congestion window according to the quantity of the received NIL ACK grouping, and increases the congestion window by one data grouping size when receiving one NIL ACK grouping; Step 4.2, if the data packet loss is caused by congestion, the router preferentially discards the transmitted NIL packet; Step 4.3, the source end determines whether the packet loss is caused by congestion according to the step 4.2, if congestion exists, the congestion window is kept to meet the maximum window size without congestion, if the congestion exists, the NIL packet without error code can receive the NIL ACK packet, the NIL packet with error code can not receive the NIL ACK packet, the congestion window can be restored to the size before the window is halved due to congestion, when the congestion occurs in the retransmission stage, the SACK option can be adopted in the NIL packet, the NIL ACK packet informs the source end of the packet received by the destination end, so as to finish quick recovery and return to the step 2; and 4.4, after the source end sends connection establishment request information to the destination end, if the destination end does not feed back response information in time within a set time, disconnecting and reestablishing connection between the source end and the destination end.
2. 2. The end-to-end transmission method for a long-delay high-error communication environment according to claim 1, wherein the step 2 specifically comprises the following steps: step 2.1, when congestion occurs in step 1, calculating an ideal throughput under the current network condition through a formula (2): (2) In the formula (2), the amino acid sequence of the compound, For ideal throughput in the current network scenario, For the value of the congestion window at the previous time, Is the minimum round trip delay; step 2.2, calculating by the formula (3), wherein the actual throughput under the current network condition is as follows: (3) In the formula (3), the amino acid sequence of the compound, For the actual throughput under the current network conditions, For the value of the congestion window at the previous time, Is the current round trip delay; Step 2.3, calculating the difference between the ideal throughput and the actual throughput by the formula (4), and estimating the buffer memory in the router: (4) In equation (4), diff is the estimated amount of cache in the router; Step 2.4, comparing the router cache size Diff estimated in step 2.3 with a threshold α and a threshold β, and adjusting the size of the congestion window cwnd according to formula (5): (5) And 2.5, when the slow start threshold is reduced to half of the current window and the congestion window is changed to be 1 packet size, disconnecting and reestablishing the connection between the source terminal and the destination terminal.
3. 3. The end-to-end transmission method for a long-delay high-error communication environment according to claim 1, wherein the step 3 specifically comprises the following steps: Step 3.1, selecting retransmission through SACK option of TCP protocol, retransmitting lost packet only, the destination feeds back the received and buffered discontinuous data packet information to the source, the source checks which packet is lost according to the information, and sends corresponding data packet to the destination; step 3.2, the destination terminal sends a feedback response through a reverse link to tell the source terminal of the number of the data packet which is not received correctly; And 3.3, the source end resends the data packet which is not successfully transmitted according to the number of the data packet which is not correctly received and provided by the destination end.
4. 4. An end-to-end transmission system for a long-delay high-error communication environment, comprising: The fast starting module is used for accelerating the sending rate of the packet during starting and improving the starting throughput; The congestion avoidance module is used for detecting whether the packet is lost due to error code or congestion when the fast starting module is in the condition of packet loss, and realizing congestion avoidance according to different conditions; the fast retransmission module is used for retransmitting lost packets which occur in the fast starting module and the congestion avoiding module, so that the retransmission rate is accelerated, and the network throughput is improved; and the fast recovery module is used for enabling the congestion window to be fast recovered to the level before congestion avoidance when the fast starting module, the congestion avoidance module and the fast retransmission module carry out window congestion during packet transmission, so that the network throughput is accelerated and improved.
5. 5. An end-to-end transmission device for a long-delay high-error communication environment, comprising: a memory for storing a computer program implementing an end-to-end transmission method for a long latency high error communication environment according to any of claims 1-3; A processor for implementing an end-to-end transmission method for a long latency high error communication environment according to any of claims 1-3 when executing said computer program.
6. 6. A computer readable storage medium, characterized in that the computer readable storage medium stores a computer program, which when executed by a processor implements the end-to-end transmission method for a long latency high error communication environment according to any of claims 1-3.

Description

End-to-end transmission method, system, equipment and medium for long-delay high-error code communication environment Technical Field The invention relates to the technical field of spatial information, in particular to an end-to-end transmission method, system, equipment and medium for a long-delay high-error code communication environment. Background The satellite network can provide communication service for areas which cannot be covered by the ground mobile communication network such as desert areas, ocean areas and the like, can realize global broadband service access, meets the transmission requirement of future diversified services, and becomes an important component in the next generation mobile network. The existing satellite network transport layer protocol TCP (Transmission Control Protocol) completes end-to-end transmission through slow start, congestion avoidance, fast retransmission and fast recovery, firstly starts to increase with a double index from 1 through a congestion window of a source end, once the network is congested, a receiving response feedback of a destination end is overtime, a slow start threshold becomes half of a current sending window, the congestion window is reduced to zero, and increases slowly with a linear increasing speed from zero to the slow start threshold, when the source end receives three retransmission requests with the same number from the destination end, the source end does not wait for overtime any more, the packets with the number are retransmitted immediately, and the slow start threshold is set to the current congestion window size, the congestion window becomes half of the original, and increases slowly with the linear increasing speed, but has the following disadvantages: (1) The initial value of the congestion window is increased from 1 by a double index, so that the initial data sending rate of a source end is influenced, the throughput of the system is reduced, and the end-to-end transmission delay is increased; (2) The congestion avoiding stage is that after each time a successfully transmitted feedback information is received, the congestion window is only increased linearly by one unit length, so that the source end transmission rate is slowly improved, the throughput of the system is reduced, and the end-to-end transmission delay is increased; (3) And in the fast retransmission stage, the source end performs retransmission operation after receiving 3 repeated feedback information, so that the retransmission interval is increased, the time for the source end to successfully send the retransmission packet is prolonged, the throughput of the system is reduced, and the end-to-end transmission delay is increased. The problem (An Enhanced TCP Vegas Algorithm Based on Route Surveillance and Bandwidth Estimation over GEO Satellite Networks,"2010International Conference on Measuring Technology and Mechatronics Automation,2010,pp.464-467,doi:10.1109/ICMTMA.2010.663.), of satellite network congestion avoidance is studied by Qu and the like, but the problem of long time delay in a large-scale satellite network is not considered, in a practical scene, the satellite network has higher satellite-to-ground height, larger propagation delay, LEO-to-ground round trip delay of about 50ms, MEO-to-ground round trip delay of about 250ms and high orbit satellite-to-ground round trip delay of about 239-280ms, and the time delay of the magnitude can inevitably influence the whole congestion control result. Similarly, j.wang and k.shim, et al, optimize congestion control in a satellite network by optimizing queue management, consider queuing problems caused by long delay and high-error packet loss (Design of Nonlinear Control for Active Queue Management in TCP Satellite Communication Networks,"2020IEEE Aerospace Conference,2020,pp.1-9,doi:10.1109/AERO47225.2020.9172560.),, but the method for marking report and distinguishing packet loss based on main queue management is imperfect, and changes the TCP frame, and controls the TCP in two layers, which only gives a low-layer control design, is imperfect for the high-layer design, is incompatible with the existing protocol frame, and cannot be practically applied in the existing satellite network system. Disclosure of Invention In order to overcome the disadvantages of the prior art, the present invention aims to provide an end-to-end transmission method, system, device and medium for a long-delay high-error communication environment, which are characterized in that network throughput is improved and end-to-end transmission delay is shortened by transmitting NIL packets to detect network resources through a connection establishment stage, and by adjusting congestion windows and fast retransmission of lost packets after congestion occurs. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: An end-to-end transmission method facing to a long-delay high-error code communication envir