Based on the work of Ringel and Green, one can define the (Drinfeld) double Ringel--Hall algebra
${\mathscr D}(Q)$ of a quiver $Q$ as well as its highest weight modules. The main purpose of the present paper is to show that
the basic representation $L(\Lambda_0)$ of ${\mathscr D}(\Delta_n)$ of the cyclic quiver $\Delta_n$ provides a realization
of the $q$-deformed Fock space $\bigwedge^\infty$ defined by Hayashi. This is worked out by extending a
construction of Varagnolo and Vasserot. By analysing the structure of nilpotent representations of $\Delta_n$,
we obtain a decomposition of the basic representation $L(\Lambda_0)$ which induces the Kashiwara--Miwa--Stern
decomposition of $\bigwedge^\infty$ and a construction of the canonical basis of $\bigwedge^\infty$ defined by
Leclerc and Thibon in terms of certain monomial basis elements in ${\mathscr D}(\Delta_n)$.