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Forward Error Correction

Forward Error Correction is a powerful technique for improving the performance of error-prone channels found in communication systems. The performance of FECs can be evaluated based on their distance from Shannon limit. We offer traditional and advanced methods of forward error correction to improve performance of error-prone channels.

Spectral Efficiency and EbNo (dB)
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Examples of our modems’ advanced FECs are:


The high performance LDPC FEC is specifically design to optimize performance at low and mid-tier symbol rates. VersaFEC-2 long-block provides 38 ModCods (BPSK to 32-ARY) with performance generally better than DVB-S2 at significantly lower latency and short-block provides 36 ModCods (BPSK to 32-ARY) with higher coding gain than first generation VersaFEC and similar latency. All higher order constellations are quasi-circular for optimal peak-to-average performance. Both CCM and ACM operation is support for long block and short block.

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A system of short-block, low latency Low Density Parity Check (LDPC) codes designed to support latency-sensitive applications, such as cellular backhaul over satellite. Designed to provide maximum coding gain while minimizing the end-to-end latency, VersaFEC provides an excellent alternative to existing LDPC and DVB-S2 codes.

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Low-Density Parity-Check Codes (LDPCs)

When used in networks with lower FEC coding rates and higher data rates, the power and bandwidth savings offered by LDPC are most apparent. In conjunction with LDPC is 8-QAM modulation, which exhibits far superior performance compared with conventional 8-PSK. When LDPC and 8-QAM are combined, satellite transponder utilization can be maximized, resulting in minimized operating expenses.

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Digital Video Broadcasting-Satellite (DVB-S) has been successfully deployed globally with outstanding results. DVB-S2 (the 2nd generation of DVB-S), as specified by ETSI EN 302 307, provides an increase in spectral efficiency and advanced operational features. With a broad range of modulation and coding formats, DVB-S2 permits users to tailor a link for the available bandwidth and power to optimize link performance. Whether a link is for Direct-to-Home (DTH) or Digital Satellite News Gathering (DSNG), contribution or distribution, we offer a format available to suit each application.

2nd Generation Turbo Product Codes (TPC)

Allows our modems to maintain a prescribed bit error rate at a lower signal to noise ratio than most other FEC techniques. It delivers significant performance improvement when compared to Viterbi with concatenated Reed-Solomon. TPC simultaneously offers increased coding gain, lower decoding delay and significant bandwidth savings.

VersaFEC® is a Registered Trademark of Comtech EF Data