High Throughput Fully Processed Payload for Broadband Access Networks

In order to compete with terrestrial services, satellite systems for broadband access networks must maximise the useful capacity provided by each satellite. The High Throughput system has been carefully optimised in terms of capacity as part of an ESA R&D contract. This system provides Kaband links between approximately one hundred user beams and a network of gateway stations over a regional European coverage from geostationary orbit. On-board digital processing is essential in providing the routing and frequency plan flexibility needed to use the resources efficiently across so many spot beams. Despite the large bandwidths involved, recent advances in ASIC, mixed signal conversion and digital interconnect technologies, make a fully processed payload handling up to 50 GHz of processed bandwidth feasible in the relatively near term. As well as fine channel demultiplexing, fully flexible routing and gain control, the digital processor also supports digital beamforming across a 500 MHz band, allowing for flexible frequency reuse and coverage that can be reconfigured in orbit. All these functions can be demonstrated at speed for a reduced number of processing chains using currently available commercial off-the-shelf FPGA-based processing cards.