  Pairing symmetries of iron-based superconductors are investigated
systematically in a five-orbital model within the different regions of
interaction parameters by functional renormalization group(FRG). Even for a
fixed Fermi surface with both hole and electron pockets, it is found that
depending on interaction parameters, a variety of pairing symmetries, including
two types of $d$-wave and two types of $s$-wave pairing symmetries, can emerge.
Only the $d_{x^2-y^2}$ and the $s\pm$ waves are robustly supported by the
nearest-neighbor(NN) intra-orbital $J_1$ and the next-nearest-neighbor(NNN)
intra-orbital $J_2$ antiferromagnetic(AFM) exchange couplings respectively.
This study suggests that the accurate initial input of interaction parameters
are essential to make FRG an useful method to determine the leading channel of
superconducting instability.
