Concept for an all-digital satellite communications earth terminal

Current DoD requirements call for a single enterprise terminal supporting up to 48/96 (threshold/objective) transmit and 56/112 (threshold/objective) receive communications carriers, not considering future expansion. The number of links supported by an enterprise terminal dictates aggregate servicing capacity. A single teleport/standardized tactical entry point (STEP) site can consist of five or more terminals operating in several frequency bands. Each carrier requires individual converter and modem chains, which are linked to the antennas with a complex switch matrix subsystem. This architecture results in severe size, weight, and power (SWAP) constraints that limit expansion to support objective capacity and connectivity requirements within available facility space and infrastructure. By moving the digital conversion as close to the antenna as possible, a number of efficiencies in SWAP and performance can be achieved. The individual converters can be replaced with wideband, multi-carrier digital up and down converters co-located with the antenna. The complex switch matrix can be eliminated and replaced with a lightweight digital distribution system. The modem functions can be consolidated into a multi-card enclosure, where several carriers can be implemented on a single programmable processor card. In addition to reducing terminal complexity and SWAP, this approach also enables concepts such as hybrid mesh networks, decentralized power monitoring and control, and remote terminal control. This has the potential to dramatically increase satellite network efficiency and improve utilization of expensive satellite assets. This paper expands upon preliminary work performed to date at CERDEC.