Convolutional Beamspace Using IIR Filters

Abstract

The recently introduced convolutional beamspace (CBS) method has some advantages over traditional beamspace methods in array processing. This paper introduces a variant which uses IIR instead of FIR filters in the convolutional layer. In CBS, the sources falling in the stopband are assumed to be sufficiently attenuated so that we can identify the pass-band DOAs. An IIR filter often requires a much lower order for the same set of magnitude response specifications. Hence, the computational complexity of IIR-CBS can be smaller than FIR-CBS. Moreover, IIR-CBS can even give smaller DOA estimation errors than FIR-CBS because the longer FIR filter length means shorter steady-state filter output length, which leads to larger estimation errors. The advantages of IIR-CBS are verified by numerical examples.