Heuristics Multiphysical Channel Switching and Dual-Hamming Distance-Based RWA in Satellite–Terrestrial Integrated Networks

Satellite-terrestrial integrated network (STIN) plays a crucial role in achieving 3-dimensional full-area coverage. STIN enables the Internet of Things (IoT) industry to realize the integrated space-air-ground communication. The stability of satellite-terrestrial communication and the quality of service (QoS) in low earth orbit optical satellite networks (LEO-OSNs) need to be improved, especially for satellite-based IoT (SIoT) services. To address these challenges, we propose the heuristics multi-physical channel switching and dual Hamming distance-based routing and wavelength assignment (RWA) scheme (HMPS-DHR). Based on dual HAPs deployment architecture and link conditions-aware signal-to-noise ratio (SNR) thresholds model, the multi-physical channels can be flexibly switched among free-space optical (FSO) laser links, Ka-band and S-band microwave links to ensure the stability of the satellite-terrestrial feedback links (FLs). Meanwhile, the traffic conflict gain-adaptive and load-aware dual Hamming distance RWA (TCG-LDHR) algorithm is proposed to optimize the routing, address the RWA problem, and enhance QoS. Simulation results demonstrate that the proposed HMPS-DHR effectively guarantees the communication success rates between satellite and ground at approximately 98.9% to 99.2%, and improves the QoS metrics involving total delay, average throughput, packet loss rate, and blocking rate, by 15.6% to 56.4% compared with the Dijkstra-FF and the ant colony optimization with adaptive load balance small window strategy under hop number loose constraint (ACO-ALB-SWS-HNLC), respectively. HMPS-DHR shows acceptable robustness to synchronization deviations despite unavoidable millisecond-level timing mismatches. Although the QoS performance of the proposed HMPS-DHR is slightly lower than that of the integrated multipath network coding (IMPNC) scheme, its computational complexity is significantly reduced.