Truncation error analysis in computing of SEP and SEP floor for partially coherent receiver of MPSK signals over composite fading channels.

•We present expressions for evaluation of SEP and SEP floor in the form of Fourier series.•Novel analytical expressions for Fourier coefficients are derived.•Novel expressions of upper bounds for truncation error are derived in terms of elementary mathematical functions.•Novel analytical expressions can be used in determining the numerical values of SEP and SEP floor under given accuracy.