# Traffic-Predictive Routing Strategy for Satellite Networks
## 2 Related Research
The results show that the AODV routing protocol can be effectively applied to satellite networks. [PERSON] et al. proposed a routing policy AODV-LD based on link duration [14]. This strategy estimates the link duration according to the satellite's position and speed. Simulation results show that this strategy can achieve the same packet delivery rate as AODV in all scenarios. [PERSON] et al. proposed a routing algorithm based on the delivery success rate [15]. This algorithm obtains the historical delivery success rate of the channel through mathematical statistics and selects the path with the highest delivery success rate for forwarding. However, this strategy has a large transmission delay. The common feature of the routing discovery mechanism in the on-demand routing protocols is that the route is maintained only when the node has data to send. The source node sends the routing request packet, and the intermediate node receiving the routing request packet will continue to forward the packet, namely the RREQ packet, regardless of the current load intensity. After receiving a routing request packet, the destination node returns a response packet (RREP packet) along the shortest path of the request packet. Compared with the table-driven routing protocol, this on-demand routing mechanism can greatly reduce the control groups in the network and reduce the network burden when there is less demand for routing request grouping and routing maintenance grouping. However, when the traffic volume of network communication reaches a certain number, the reliability of network transmission still cannot be guaranteed. In addition, when the communication traffic is heavy, the number of node connection pairs in the network will also increase, resulting in an increasing traffic load. Additional overhead becomes difficult to control, and network performance deteriorates dramatically. The root cause of the above problems is that the routing mechanism of the above protocols does not consider the problem of node load balancing. The essence of load balancing is to avoid congested nodes in route selection and distribute load reasonably in the presence of multipath routes. Forward packets through nodes with sufficient spare capacity to reduce existing and potential local congestion. Some intermediate nodes ignore their load status and directly forward packets after receiving them, which makes the load of heavier intermediate nodes not alleviated. This causes a large number of data packets to be discarded, increasing the average end-to-end delay and packet loss rate. Therefore, the unbalanced flow distribution will cause the heavy load node to run out of power quickly and die. With the increasing number of dead nodes, the connectivity of the network will rapidly decline and network fragmentation will occur, eventually leading to the failure of routing requests and data transmission. To solve the problem of network congestion in AODV routing, many scholars have studied load-balancing routing based on the on-demand routing protocol. Existing load-balancing routing protocols are divided into multi-path routing protocols and alternative path routing protocols according to routing and traffic distribution methods [16]. Multipath routing protocols take certain measures to allocate network traffic to multiple routes for transmission and distribute data traffic through multiple paths to ensure that all paths are fully utilized to achieve load balancing and improve network performance. [PERSON] et al. proposed a substream routing algorithm with load and shared bottleneck awareness [17], which selects routes for new substreams according to the available bandwidth of each route and avoids bottlenecks of other substreams. Experiments show that the proposed scheme can achieve higher system throughput. [PERSON] et al. used multipath TCP (MPTCP) in the low-orbit satellite system and proposed a routing design framework based on MPTCP [18].