Synthesis of folded, pipelined architectures for multi-dimensional multirate systems

Motivated by the need for designing efficient architectures for two-dimensional discrete wavelet transforms (DWTs), this paper presents a novel multi-dimensional (MD) folding transformation technique which can be used to synthesize control circuits for pipelined architectures for a specific class of multirate MD digital signal processing (DSP) algorithms. Although a multirate MD DSP algorithm contains decimeters and expanders which change the effective sample rate of a MD discrete time signal, MD folding time-multiplexes the algorithm to hardware in such a manner that the resulting synchronous architecture requires only a single clock signal for the clocking of the datapath. Feasibility constraints are derived for folding a 2-D data-flow graph (DFG) onto a given set of hardware functional units according to a specified schedule. Area/power efficient architectures are derived for 1-4 level 2-D discrete wavelet transforms (DWT) with 18.5-23.3% savings in storage area.