Beam Hopping for Multi-Beam LEO Satellite Systems with Integrated Sensing and Communications

The urgent need for efficient utilization of spectral and hardware resources has led to the emergence of integrated sensing and communications (ISAC). Some research is trying to introduce ISAC into low earth orbit (LEO) satellite systems, which adopt multi-beam techniques and a full frequency reuse (FFR) scheme. To ensure efficient communication and sensing quality during the forward link, we propose a two-stage beam hopping method based on multi-agent actor-critic. The beam pattern and power allocation are optimized separately. Agents representing directions and allocated powers generate dispersed beam patterns to avoid interference between beams, and optimally allocate the limited onboard resources. Experimental results verified the effectiveness of our proposed method in avoiding inter-beam interference, improving system throughput, reducing latency, and allocating resources on demand.