The Tunka Radio Extension (Tunka-Rex) is a radio detector at TAIGA facility located in Siberia nearby the southern tip of Lake Baikal. Tunka-Rex measures air-showers created by high-energy cosmic rays, in particular the lateral distribution of the radio pulses produced during the development of the air-shower. The depth of the air-shower maximum, which statistically depends on the mass of the primary particle, is determined as function of the slope of the lateral distribution. Starting from 2015, Tunka-Rex acquires data jointly with Tunka-Grande, which adds a measurement of the muonic shower component to the calorimetric radio measurements, and gives complementary information about air-shower. To interpret these measurements, one has to take into account systematic uncertainties given by hadronic models. Furthermore, it is important to investigate different shower geometries, since the received signal depends on the inclination and dimensions of cascade. In the frame of this study we perform simulations using the CONEX and CoREAS software packages of the recently released CORSIKA v7.5 including the modern high-energy hadronic models QGSJet-II.04, EPOS-LHC, and SIBYLL 2.3. We report the last results on this study, and discuss the prospects of future improvements based on these simulations.