Development of an adaptive array based on subband signal processing

Adaptive arrays are recognized as a solution to multipath fading environments that can be a serious problem in high-speed mobile communication systems. However, huge computational loads are required due to its spatio-temporal signal processing. Subband signal processing has been known as a parallel signal processing scheme on the frequency domain. It allows us to allocate heavy computational loads to several processors when it is implemented in digital signal processors (DSPs) or field programmable gate arrays (FPGAs) and so on. Basically, the performance of adaptive arrays based on subband signal processing is identical to that based on time domain signal processing. However, several types of configurations are possible. As a result, there is a configuration that is very advantageous in terms of the computational reduction even though its performance is slightly degraded compared to one configured in the time domain. In this paper, an adaptive array based on subband signal processing that can intensively reduce computational loads is implemented by using DSPs and its performance is verified through experiments in an anechoic chamber. Finally, the computational loads of adaptive arrays are examined and the implemented adaptive array is shown to realize very efficient signal processing.