Since future systems will also be characterized by the on-board availability of a set of coding and modulation schemes at several spectral efficiencies and different SNR thresholds, the usage of Variable Coding Modulation (VCM) techniques can improve the system performance, by adapting case-by-case the coding/modulation scheme to the actual local atmospheric conditions. In the frame of the “Advanced Techniques for High Data Rate Links for Earth Exploration Satellites" study, ESA Contract n. 22455/09/NL/JK, a set of SW modules was developed to allow the system designer computing the achievable end-to-end performance of the data downlink architecture of Earth Observation satellite in LEO orbit when using VCM techniques and comparing it versus the achievable figure when Constant Coding Modulation (CCM) is used. In particular, the SW implements modulation and coding described in the CCSDS standard, pre-distortion techniques, and on-ground algorithms for mitigation of channel contribution to dual-polarization transmission. Moreover, the SW allow the user selecting the main mission parameters (e.g. orbit, ground station, link availability, non-linear amplifier, on-board RF filters, EIRP etc..) according to its customized scenario.