An onboard digital transparent processor for a multi-beam satellite

This paper describes an efficient design of digital transparent processor payload subsystem, developed at Space Applications Centre (ISRO) for a multi-beam, high throughput communication satellite. The digital transparent processor, also called digital mesh processor, onboard a multi-beam communication satellite performs the functions of slicing the uplink bandwidth into fine granules, switching it as per user requirements and combining the bandwidth-granules for downlink transmission. It effectively serves as exchange-in-the-sky providing inter-beam and intra-beam connectivity among users in various spot beams; the connectivity may be unicast, multicast or broadcast. The digital transparent processor has four main subsystems namely Frequency Demultiplexer, Channel Switch, Frequency Multiplexer and Mesh Network Manager. A design verification model of the digital transparent processor has been implemented and its design, hardware and software implementation details, simulation and hardware performance results are presented.