Sergio Benedetto , Roberto Garello , and Guido Montorsi , Politecnico Di Torino

This article presents the novel FPGA-based 1 Gb/s near-Shannon-limit ACM modem developed within the MHOMS program with particular focus on the advanced modem algorithm solutions devised. A number of powerful FEC schemes have been analyzed as possible candidates for the MHOMS modem, and the final selection is justified in terms of the best tradeoff between complexity and performance. Stateof-the-art modulation and demodulation algorithms are also presented, including nonlinearity dynamic precompensation techniques and innovative syncrhonization strategies required by the selected powerful modulation and coding schemes. Overall modem performances are also shown for a variety of spectral efficiencies. MHOMS: HIGH-SPEED ACM MODEM FOR SATELLITE APPLICATIONS The present contribution describes the achievements obtained within the ESA Technology Research Program Modems for High-Order Modulation Schemes (MHOMS), Contract No. 16593/02/NL/EC, led by Alenia Spazio (a FINMECCANICA Company) as prime contractor. 1 The phase noise used for the design and throughout the performance simulations is the commercial user equipment mask defined in the DVB-S2 standard [2]. The MHOMS