Unit Groups of Some Group Rings

Let $RG$ be the gruop ring of the group $G$ over ring $R$ and $\mathscr{U}(RG)$ be its unit group. Finding the structure of the unit group of a finite group ring is an old topic in ring theory. In, G. Tang et al: Unit Groups of Group Algebras of Some Small Groups. Czech. Math. J. 64 (2014), 149--157, the structure of the unit group of the group ring of the non abelian group $G$ with order $21$ over any finite field of characteristic 3 was established. In this paper, we are going to generalize their result to any non abelian group $G=T_{3m}$, where $T_{3m} = \langle x,y\,|\,x^m=y^3=1,\,x^y=x^t\rangle$.