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This paper deals with the feasibility of the new receiver scheme for telecommand space links, based on the adoption of short low-density parity-check codes recently introduced in the standard. Being able to reduce significantly the required signal-to-noise ratio, these codes have an impact on the acquisition, tracking and synchronization issues. All these aspects have been faced, both theoretically and practically through the realization of a breadboard that implements the core elements of the on-board receiver, and is able to demodulate and decode uplink signals employing the new codes. The breadboard incorporates innovative solutions to cope with the acquisition and synchronization problems, and a pioneering implementation of non-iterative decoders based on the most reliable basis algorithm.

The Consultative Committee for Space Data Systems has recently updated its recommendation for uplink communication systems, to cope with new requirements for telecommand and modern profiles and applications. Two short Low-Density Parity-Check (LDPC) codes have been added to the Coding and Synchronization sublayer options, to improve the link performance. In this paper we focus on the real-time implementation of the transmitter for the Ground Station segment. We analyze the critical modules, in particular LDPC encoding, for which two efficient solutions based on a Shift Register Adder Accumulator and on Winograd convolution are considered. We then discuss the selection of a proper hardware or software platform, and we show that a Central Processing Unit-based solution is able to achieve the high data-rates required by the new uplink applications.