We show that if the Hardy-Littlewood maximal operator is bounded on a reflexive Banach function space X(R) and on its associate space X ′ (R), then the space X(R) has an unconditional wavelet basis. As a consequence of the existence of a Schauder basis in X(R), we prove that the ideal of compact operators K(X(R)) on the space X(R) is contained in the Banach algebra generated by all operators of multiplication aI by functions a ∈ C(Ṙ), wherė R = R ∪ {∞}, and by all Fourier convolution operators W 0 (b) with symbols b ∈ CX(Ṙ), the Fourier multiplier analogue of C(Ṙ).2010 Mathematics Subject Classification: Primary 47G10; Secondary 46E30, 42C40. Key words and phrases: Banach function space, wavelet basis, multiplication operator, Fourier convolution operator, compact operator, Hardy-Littlewood maximal operator. The paper is in final form and no version of it will be published elsewhere.[1]