Joint Beam Hopping and Precoding for Dense LEO Satellite Communication Systems

Beam hopping (BH) is a widely adopted technique in multi-beam satellite communication systems, and it can effectively improve the system capacity. However, conventional BH with full frequency reuse requires spatial isolation to avoid inter-beam interference, and it will impose restrictions on the flexibility of BH and achievable system capacity. By combining the BH and multi-beam precoding, it is beneficial to satisfy the uneven traffic demands and keep the flexibility of beam management. Different from the existing works that focus on the joint BH and precoding for a single satellite, we investigate the joint multi-satellite cell association, BH pattern design and multi-beam precoding problem for dense low earth orbit (LEO) satellite communication systems. To tackle the complex problem, we decompose it into two subproblems. First, a many-to-one matching based multi-satellite cell association algorithm is proposed, which balances the load among satellites and mitigates interference among activated cells. Second, many-to-many matching based BH pattern design and quadratic transform based precoding algorithms are proposed and alternately optimized to solve the joint BH and precoding problem. Lastly, a multi-satellite joint BH and precoding algorithm based on alternating optimization (MJBHPAO) is proposed to solve the entire problem. The effectiveness of the proposed algorithm is verified with various parameters, and simulation results show that the proposed algorithm performs better than the referred schemes.