US-12621051-B2 - Leo satellite congestion control routing method

Abstract

A Low Earth orbit (LEO) satellite congestion control routing method is disclosed, including: Step 1: A LEO satellite periodically detecting queue lengths of a plurality of ports and informing a Geostationary Earth Orbit (GEO) satellite of queue lengths of congested ports in the plurality of ports; Step 2: The GEO satellite sending the queue lengths of congested ports to a ground station, and a computing center of the ground station calculating link status weights according to the queue lengths of congested ports; Step 3: According to the link status weights, the computing center of the ground station determining a congestion area; Step 4: The computing center of the ground station calculating a routing table of satellites in the congestion area, and the ground station sending the routing table to a LEO satellite inside the congestion area; Step 5: The LEO satellite in the congestion area receiving the routing table, and performing end-to-end transmission of data packets to a destination LEO satellite according to the routing table.

Inventors

• Jiaxin Zhang
• Kaiwei Wang
• Xing Zhang
• Rui Li
• Zhaoyang Chang
• Yilong Zhang
• Hang Lu

Assignees

• BEIJING UNIVERSITY OF POSTS AND TELECOMMUNICATIONS

Dates

Publication Date

20260505

Application Date

20240308

Priority Date

20230309

Claims (6)

1. 1 . A Low Earth orbit (LEO) satellite congestion control routing method, comprising: Step 1: A LEO satellite periodically detecting queue lengths of a plurality of ports and informing a Geostationary Earth Orbit (GEO) satellite of queue lengths of congested ports in the plurality of ports; Step 2: The GEO satellite sending the queue lengths of congested ports to a ground station, and a computing center of the ground station calculating link status weights according to the queue lengths of congested ports; Step 3: According to the link status weights, the computing center of the ground station determining a congestion area; Step 4: The computing center of the ground station calculating a routing table of satellites in the congestion area, and the ground station sending the routing table to a LEO satellite inside the congestion area; Step 5: The LEO satellite in the congestion area receiving the routing table, and performing end-to-end transmission of data packets to a destination LEO satellite according to the routing table.
2. 2 . The method according to claim 1 , wherein in step 2, the link status weights are expressed by the following formula (1): w n , m , t = { - ( L n , m , t v + D n , m , t c ) , if ⁢ m ⁢ denoting ⁢ congested ⁢ ports - D n , m , t c , if ⁢ m ⁢ denoting ⁢ non - congested ⁢ ports ( 1 ) wherein w n,m,t is a link status weight of the m th port of the n th LEO satellite s n at time t, L n,m,t is amount of data occupied by a queue of the m th port of the n th LEO satellite s n at time t, ν is a packet processing rate, D n,m,t is a queue length of the m th port of the n th LEO satellite s n at time t, c is the speed of light, m and n are positive integers.
3. 3 . The method according to claim 2 , wherein the number of LEO satellites is N, n=1, . . . , N, and the number of the plurality of ports is 4, m=1, . . . , 4, the method further comprises: the computing center of the ground station performing normalization processing on w n,m,t to obtain a normalized link status weight w n , m , t ′ , using the following formula (2): w n , m , t ′ = w n , m , t - min ⁡ ( w 1 , 1 , t , w 1 , 2 , t , … , w N , 4 , t ) max ⁡ ( w 1 , 1 , t , w 1 , 2 , t 1 , … , w N , 4 , t ) - min ⁡ ( w 1 , 1 , t , w 1 , 2 , t , … , w N , 4 , t ) ( 2 ) wherein max( ) denotes a function to find a maximum, and min( ) denotes a function to find a minimum; and the computing center of the ground station determining a satellite network status s t at time t, using the following formula (3): s t = { w 1 , 1 , t ′ , w 1 , 2 , t ′ , … , w N , 4 , t ′ } . ( 3 )
4. 4 . The method according to claim 3 , wherein a range of the congestion area is determined by a flooding hop a t at time t, a t is a positive integer, a maximum value of a t is A, and a t is calculated by using a ε-greedy strategy, given by the following formula (4): a t = { arg a ∈ { 1 , 2 , … , A } ⁢ max ⁢ Q ⁡ ( s t , a ) if ⁢ p = ε random ⁢ { 1 , 2 , … , A } if ⁢ p = 1 - ε ( 4 ) wherein ε is an exploration rate, and 0<=ε<=1, p is a probability, Q(s t , a) denotes an output of a full-connection neutral network when inputting s t and a.
5. 5 . The method according to claim 1 , wherein in step 5, the performing comprising: based on a destination address of a data packet and the routing table, selecting a set of candidate destination satellites from LEO satellites inside the congestion area using a distributed routing method, wherein next hop of each candidate destination satellite is out of the congestion area; reading link status weights of the candidate destination satellites for the routing table, and selecting a satellite with a smallest weight as the destination LEO satellite.
6. 6 . The method according to claim 5 , wherein the distributed routing method comprising: according to a set of candidate satellites determined based on a destination address of a data packet, performing one of the following: if there is only one candidate satellite in the set, selecting the only one candidate satellite as the destination LEO satellite of next hop; if there are a plurality of candidate satellites in the set, and only one candidate satellite is out of the congestion area, selecting the only one candidate satellite as the destination LEO satellite of next hop; if there are a plurality of candidate satellites in the set, and more than one candidate satellite is out of the congestion area, selecting a candidate satellite with the smallest weight from the more than one candidate satellite as the destination LEO satellite of next hop; if there are a plurality of candidate satellites in the set, and the plurality of candidate satellites are out of the congestion area, selecting a candidate satellite with the smallest weight from the plurality of candidate satellites as the destination LEO satellite of next hop.

Description

CROSS REFERENCE This application claims priority to Chinese Patent Application No. 202310223892.0, entitled “an Area-Segmentation Enabled Congestion Control Routing Method in a LEO Satellite Network” filed on Mar. 9, 2023, which is incorporated by reference in its entirety. TECHNICAL FIELD The present application relates to the field of the satellite communication systems, and in particular to a congestion control routing method in mega-constellation. BACKGROUND In mega-constellation networks, considering issues such as large signaling overhead and limited on-board resources, it is very difficult to design a reliable routing method that takes into account user service quality. Especially in scenarios where the business volume is large and unevenly distributed, routing transmission may also face the problems of load imbalance and network congestion. The traditional method to solve this problem is the global update routing method. The method simplifies the routing mechanism, floods fault information to all nodes with routing calculation functions, implements centralized management and control of the satellite network, calculates routing tables, and completes rerouting. The inventor X. Haitao et al. disclosed in the invention patent application number CN202210681267.6 and the invention title “A Method and System for Optimal Routing of Multiple LEO Satellites” that the method includes: S1. The terminal equipment establishes a data connection with the ground base station, and the terminal equipment sends a first communication request to the ground base station; S2. After receiving the first communication request, the ground base station performs ephemeris calculation; The ground base station sends a second communication request to a LEO satellite that is within the beam coverage area and can provide business services; S3. After receiving the second communication request, the LEO satellite performs inter-satellite measurement through the ranging communication integrated module, perform topology update and route calculation based on the ranging results, and obtain the updated constellation topology information and route calculation results; S4. The LEO satellite sends the updated constellation topology information and route calculation results back to the ground base station; S5. The ground base station evaluates the congestion probability of the LEO satellite based on the real-time tracking of traffic in the LEO satellite; S6. The ground base station evaluates the congestion probability of the LEO satellite based on the calculated congestion probability of the LEO satellite. The constellation topology information and routing calculation results sent back by the satellite select a LEO satellite communication path with a small congestion probability and a short path length; S7. The terminal device communicates with the LEO satellite selected by the ground base station for communication. It is proposed to use ground base stations to complete the assessment of congested links and the calculation of communication paths. In an article titled “Research on Dynamic Topology Analysis and Routing Mechanism of LEO Satellite Networks”, W. Yinggang proposed using the ground control center to macro-control heavily congested satellites and reroute to calculate a new multi-path routing table. In an article titled “An Adaptive Routing Algorithm for Integrated Information Networks”, F. Wang et al. proposed a software-defined network architecture based on a three-layer satellite network, in which high-orbit satellites and medium-orbit satellites serve as control nodes, and LEO satellites serve as control nodes. The satellite is responsible for receiving commands and forwarding data packets. In order to deal with the above problems, the method of partially updating routing is proposed, that is, collecting part of the satellite status information to complete routing. The method relies on the satellite's own capabilities to complete routing forwarding, reducing the signaling overhead in the communication process. Inventor J. Xiaoyong and others disclosed the invention in patent application number CN202110478573.3, titled “A distributed routing management method for ultra-large-scale LEO satellite constellations”. Step S1. Build a satellite scenario; calculate the satellite network based on the Walker constellation configuration. Topological structure, use a quantitative method to divide the length interval of the inter-satellite link, and establish a lateral forwarding priority comparison table according to the variation pattern of the lateral length, Step S2. use a two-dimensional grid transmission path to find out from the minimum hop count path set The path with the shortest transmission distance; determine the forwarding direction of the data packet based on the destination address and source node address; when the data packet runs to any satellite node, the forwarding direction is determined based on the lateral forwarding priorit