The Algebra of a $q$-Analogue of Multiple Harmonic Series

We introduce an algebra which describes the multiplication structure of a family of $q$-series containing a $q$-analogue of multiple zeta values. The double shuffle relations are formulated in our framework. They contain a $q$-analogue of Hoffman's identity for multiple zeta values. We also discuss the dimension of the space spanned by the linear relations realized in our algebra.