In this paper, an approximation of the average bit error rate (ABER) probability expression, standard performance measure of wireless transmission over fading channels using linear spline functions with corresponding number of segments has been provided. Further, possible approximation improvement obtained by appliance of composite piecewise spline (combination of linear and quadratic) functions has also been analyzed. For the generality purpose multipath fading that occurs through the propagation was modeled with alpha-kappa-mu distribution model, which includes as special cases other fading models, so this analysis obtains a high level of generality. It has been shown that this approximation provides a high level of accuracy in the wide range of observed conditions so this model can be applied for high-accuracy prediction of the performance measures for various wireless services.

Keywords: Spline approximations, Quadratic spline, Fading channels, Average bit error rate