In this letter we present a method for low-complexity simulation of multi-channel room impulse responses (RIRs). Low-complexity RIR methods will become inevitable in next generation communication systems having massive amounts of microphones/loudspeakers. For a room with rigid boundaries, we show that proper sampling of the free-field plenacoustic spectrum results in the solution of the wave equation at any position in the room. We show that the spatial aliasing introduced by spectral sampling represents the wall reflections. These wall reflections are usually modelled, at least in low-complexity simulation algorithms, by the creation of virtual free-field sources outside the room, an image source model commonly referred to as the image method. The image method requires O(N3) operations per receiver position, whereas the newly proposed method requires only O(N logN) operations per receiver position.
- free-field plenacoustic spectrum;image source model;low-complexity RIR method;low-complexity simulation algorithm;multi-input multi-output system;multichannel room impulse response;next generation communication system;rigid boundaries;spatial aliasing;spectral sampling;virtual free-field sources;wall reflection;wave equation;MIMO communication;acoustic signal processing;architectural acoustics;image sampling;transient response;wave equations;wireless channels