A New Receiver Architecture for Smart Antenna with Digital Beamforming

Abstract

Smart antennas are regarded as the key solution to increasing the spectral efficiency and improving the system performance in wireless communications. The high speed analog to digital converter (ADC) and digital signal processor (DSP) make the smart antenna with digital beamforming (DBF) a reality. In conventional N-element array receiving system, each element has its own RF/IF channel and ADC. In this paper, a novel smart antenna receiver with digital beamforming is proposed The essential idea is to realize the digital beamforming receiver based on bandpass sampling of multiple IF signals. The proposed system reduced receiver hardware from N IF channels and N ADCs to one IF channel and one ADC using a heterodyne RF circuitry and a multiple bandpass sampling receiver. In this scheme, the sampling rate of the ADC is much higher than the summation of the N times of the signal bandwidth. The local oscillator produces different local frequency for each RF channel. The receiver architecture is presented and the simulation of bandpass sampling of multiple signals is given