Cross-Layer Routing And Load Balancing Algorithms For MEO/LEO Satellite Networks

In satellite network systems,due to the unbalanced distribution of satellite users on the Earth's surface,the satellite load in different regions may be very different.This will lead to higher satellite network load in some satellites,and some satellites may be quite idle,which in turn may be a waste of satellite system.The waste of resources may not even meet the requirements of network QoS services.In response to the above problems,many domestic and foreign researchers have tried to use multi-layer satellite network systems for data cooperative transmission and load balancing.However,most of these solutions are based on the SOS(Satellite Over Satellite)multi-layer satellite network architecture and directly transfer the link load of low-level satellites through their high-level managers,which will further lead to network congestion in high-level satellite managers,and thus lead to unbalanced loads of high-level satellite networks.So these solutions have not fundamentally solved the problem.This paper proposes an optimized network topology for the MEO/LEO two-layer satellite network architecture and improves the satellite system utilization from the perspective of optimizing the satellite network model.In addition,this paper proposes a load balancing OTLB(Optimized Topology based Load Balancing)algorithm for the optimized topology and proposes corresponding network load balancing and congestion control mechanisms for the LEO layer and the MEO layer respectively,so as to guarantee the QoS network service..The main contributions of this paper are as follows:· This paper constructs an optimized network topology structure based on MEO/LEO.MEO layer satellites are assigned two roles: MEO managers and relay MEO satellites.On the one hand,the MEO layer satellites serve as a group of LEO satellite managersand are responsible for the collection and routing calculation of the link state reports of agroup of LEO satellites.On the other hand,each LEO satellites will choose a best relayMEO for data cooperation transmission and network load balancing.· This paper proposes the selection mode of relaying MEO satellites.According to thelink status report of all satellite nodes and the relative position relationship betweenMEO and LEO satellite nodes,a relay MEO satellite is selected for each LEO satellitenode.In the process of implementing the scheme,this paper adds the corresponding datastructure in the design of LEO layer and MEO layer satellites,so as to store the networktopology information and then realize the network routing scheme in this paper.· This paper proposes a routing scheme for the current optimized network model.Therouting scheme includes three aspects: route calculation,topology control,and satellitenode failure.In this paper,a cross-layer routing algorithm is proposed for optimizing thenetwork model,and corresponding topology control and satellite node failure handlingstrategies are proposed for the relayed MEO satellite.· This paper proposes an OTLB load balancing algorithm,including an OTLB algorithmbased on relaying MEO satellites,and an OTLB algorithm based on relaying MEO satel-lites and MEO managers.Both of the above algorithms can achieve load balancing be-tween the LEO layer and the MEO layer.This paper proposes corresponding thresholdjudgment criteria for link load,and uses different data forwarding logic under differentlink load conditions to achieve network load balancing of LEO layer and MEO layer.This paper expands the corresponding lib library of NS2.Based on this,it implements a MEO/LEO cross-layer routing and load balancing algorithm and carries out corresponding comparative experiments.Experimental results show that the proposed routing protocol and load balancing mechanism have better performance and can provide QoS network services.