Antenna-array 2D-IIR digital filters for carrier-modulated frequency-agile and cognitive wireless systems

The application of a 2D IIR digital filter, having a broadband beam-shaped 2D passband, is investigated for beamforming in narrowband wireless communication systems. Specifically, their use for interference rejection in a carrier-modulated communication system is proposed. Monte-Carlo simulations of the bit-error-rate, as a function of the antenna-side signal-to-interference ratio for a 1 GHz BPSK-modulated source operating at 25 Mbps over a 32 element array, confirm a signal-to-noise-plus-interference ratio (SINR) system gain of 10 to 15 dB relative to the non-beamformed case. The proposed method allows a single broadband beamformer to operate over a wide frequency bandwidth containing multiple frequency-agile channels. This particular application is potentially well-suited for cognition-enabled base stations.