Mixed Analog/Digital Beamforming for 60 GHz MIMO Frequency Selective Channels

Multi-antenna architectures, where beamforming processing is shared between analog and digital, are of great interest for future multi-Gbps wireless systems operating at 60 GHz. In this spectrum band, wireless systems can integrate large antenna arrays in a very small volume thanks to a wavelength of about 5 mm and thus provide the required gain to meet the severe link budget. However, the cost and power consumption of an analog front-end (AFE) chain, that carries out translation between radio frequency (RF) and digital baseband, are too high at 60 GHz to afford one AFE for each antenna. In this paper, we consider low cost multi-antenna architectures with a lower number of AFE chains than antenna elements. We propose a joint design of transmit-receive mixed analog/digital beamformers that aim at maximizing the received average signal-to-noise-ratio (SNR). The proposed scheme shows better performance than state-of-art solutions, which combine antenna selection techniques and digital beamforming.