  Permutation polynomials have many applications in finite fields theory,
coding theory, cryptography, combinatorial design, communication theory, and so
on. Permutation binomials of the form $x^{r}(x^{q-1}+a)$ over
$\mathbb{F}_{q^2}$ have been studied before, K. Li, L. Qu and X. Chen proved
that they are permutation polynomials if and only if $r=1$ and $a^{q+1}\not=1$.
In this paper, we consider the same binomial, but over finite fields
$\mathbb{F}_{q^3}$ and $\mathbb{F}_{q^e}$. Two different kinds of methods are
employed, and some partial results are obtained for them.
