The SpaceMux will enable satellite-based Internet broadband applications to be deployed over large geographical areas for both point-to-point and point-to-multi-point communications.

The system will use DVB-RCS (Digital Video Broadcast - Return Channel via Satellite) open-standard user terminals. The SpaceMux will enable individual users to communicate at 2Mbit data rates between themselves in a mesh configuration, without having to pass through a gateway.

Although intended to be a demonstration payload, SpaceMux has been designed to meet the same standards as a fully operational commercial system. The efficient bandwidth utilization is based on Multi-Frequency Time Division Multiple Access (MF-TDMA) on the uplink and Time Division Multiplexing on the downlink.

Asynchronous Transfer Mode (ATM) cells on the return link and Digital Video Broadcast (DVB) MPEG Transport Stream packets on the forward link carry traffic and signaling data.

The SpaceMux is a self-contained unit, including the Local Oscillator, the RF modules for up and down conversion, and the Electronic Power Supply. The on-board digital signal processing required to recover the ATM traffic cells, as well as the associated overhead signaling information transmitted on the uplink, is performed by the Multi-Carrier Demodulator (MCD) modules, which are Application Specific Integrated Circuit (ASIC)-based, real time, digital signal processors.

Due to the high level of complexity of the ASICs (some of which feature over 1 million gates) and Field Programmable Gate Arrays (FPGA), several new processes have been developed and qualified at EMS. EMS is now poised to manufacture the next generation of flight hardware with advanced digital packaging.

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