Time synchronization is an important issue in ad-hoc networks for reliable information exchange. The algorithms for time synchronization in ad-hoc networks are largely categorized into two types. One is based on a selection of a reference node, and the other is based on a consensus among neighbor nodes. These two types of methods are targeting static environments. However, synchronization errors among nodes increase sharply when nodes move or when incorrect synchronization information is exchanged due to the failure of some nodes. In this paper, we propose a synchronization technique for mobile ad-hoc networks, which considers both the mobility of nodes and the abnormal behaviors of malicious or failed nodes. Specifically, synchronization information extracted from a median of the time information of the neighbor nodes is quickly disseminated. This information effectively excludes the outliers, which adversely affect the synchronization of the networks. In addition, Kalman filtering is applied to reduce the synchronization error occurring in the transmission and reception of time information. The simulation results confirm that the proposed scheme has a fast synchronization convergence speed and low synchronization error compared to conventional algorithms.

This paper proposes a novel network architecture integrating a non-terrestrial network (NTN) with low-earth orbit (LEO) satellites and high-altitude platforms (HAPs) and terrestrial network (TN) with ground base stations under rate-splitting multiple access (RSMA) to enhance spectral efficiency (SE). A new resource allocation strategy is developed for efficient resource utilization across all layers. A joint resource block and power control framework (JRPS) is formulated to maximize sum-rate under quality-of-service (QoS) constraints. The non-convex JRPS problem is reformulated as a linear program and solved using an iterative successive convex approximation algorithm that ensures local optimality. Additionally, a heuristic resource allocation and power control method is also proposed to provide an effective initialization for JRPS and to serve as a performance baseline. Simulations confirm the superior performance of the proposed JRPS framework over existing benchmarks. Specifically, the proposed scheme achieves an average sum-rate improvement of up to 80% compared to conventional baselines without RSMA and up to 60% compared to RSMA combined with other allocation methods. Moreover, it ensures that approximately 90% of ground stations achieve an SE above 0.5 bps/Hz, significantly outperforming alternative strategies. Notably, integrating both LEO satellites and HAPs yields better performance than using either one alone.