Comtech EF Data's CDM-625 modem, rear panel view Comtech EF Data Corporation has made immediately available VersaFEC®, the nexgen Forward Error Correction (FEC).

VersaFEC provides maximum coding gain with the lowest possible latency to support cellular backhaul and other latency-sensitive voice, video and data applications. VersaFEC is available as a plug-in module for the CDM-625 Advanced Satellite Modem. VersaFEC is a system of short-block, low latency Low Density Parity Check (LDPC) codes designed to support latency-sensitive applications. 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.

This nexgen FEC provides an expanded choice of modulation and code combinations (ModCods). The 12 ModCod combinations offer equivalent coding gains to Comtech EF Data’s existing LDPC offering, and significantly reduce latency. VersaFEC also supports a patent-pending Adaptive Modulation and Coding (ACM) system. The ModCods were chosen to provide a continuous progression in terms of Eb/No and spectral efficiency, while reducing latency to near-theoretical minimums. For all ModCods, VersaFEC performance is within 0.7 to 1.0 dB of the Shannon Bound. This puts the performance of VersaFEC at or near the DVB-S2 performance with 16 kbit blocks. Compared to Turbo Product Codes, VersaFEC generally provides 1.0 dB or more reduction in EB/No. By using smaller block sizes and non-interleaved systematic LDPC codes, VersaFEC can also reduce latency by as much as a factor of 10 compared to alternate FECs.