  Multi-beam low earth orbit (LEO) satellites are emerging as key components in
beyond 5G and 6G to provide global coverage and high data rate. To fully
unleash the potential of LEO satellite communication, resource management plays
a key role. However, the uneven distribution of users, the coupling of
multi-dimensional resources, complex inter-beam interference, and time-varying
network topologies all impose significant challenges on effective communication
resource management. In this paper, we study the joint optimization of beam
direction and the allocation of spectrum, time, and power resource in a dynamic
multi-beam LEO satellite network. The objective is to improve long-term user
sum data rate while taking user fairness into account. Since the concerned
resource management problem is mixed-integer non-convex programming, the
problem is decomposed into three subproblems, namely beam direction control and
time slot allocation, user subchannel assignment, and beam power allocation.
Then, these subproblems are solved iteratively by leveraging matching with
externalities and successive convex approximation, and the proposed algorithms
are analyzed in terms of stability, convergence, and complexity. Extensive
simulations are conducted, and the results demonstrate that our proposal can
improve the number of served users by up to two times and the sum user data
rate by up to 68%, compared to baseline schemes.
