Combining Time-Flexible Satellite Payload with Precoding: The Cluster Hopping Approach

High throughput geostationary (GEO) satellite systems are characterized by a multi-beam wide coverage. However,
developing efficient resource management mechanisms to meet
the heterogeneous user traffic demands remains an open challenge for satellite operators. Furthermore, the spectrum shortage
and the ever increasing demands claim for more aggressive
frequency reuse. In this paper, we combine the time-flexible
payload capabilities known as beam hopping (BH) with precoding
techniques in order to satisfy user traffic requests in areas of high
demand (i.e. hot-spot areas). The proposed framework considers
a flexible beam-cluster hopping where adjacent beams can be
activated if needed, forming clusters with various shapes and
sizes. In this context, we present three strategies to design the
beam illumination patterns. First, a max-min user demand fairness satisfaction problem; second, a penalty-based optimization
is considered to penalize the occurrence of adjacent beams in an
attempt to avoid precoding whenever possible. Third, seeking a
low-complexity design, we propose a queuing-based approach
to solve the problem in a time-slot by time-slot basis trying
to provide service to users based on the requested demands.
The three methods are discussed in detailed and evaluated
via numerical simulations, confirming their effectiveness versus
benchmark schemes and identifying the pros and cons of each
proposed design.