Satellite multibeam allocation and congestion control with delay constraints

A data satellite network would have to support a broad spectrum of bursty unscheduled users with different delay constraints over time-varying atmospheric satellite channels. Since onboard resources are expensive and a broadband satellite will have many spotbeam-coverage cells within its service area, it is desirable to use agile scanning beam systems, adaptive to service requirements and channel conditions, and time-share a small number of active downlink beams. In addition, a congestion control mechanism of incoming traffic into the satellite service queues is required to provide a reasonable queueing delay within delay deadlines. In this paper, a jointly optimized scheme of multibeam allocation and congestion control based on incoming traffic and channel conditions over fading satellite downlinks with beam-sharing and delay constraints is developed. With the assumptions of quasistatic channel conditions and predictable incoming traffic rates (at least in the short term), an analytical solution for joint beam allocation and congestion control is considered. Numerical examples will be given to show that the joint scheme outperforms uniform allocation by serving, with fairness, more accepted traffic (e.g., a factor of 2 in the case of linearly distributed traffic across cells) and/or a smaller queueing delay.